1. A polyimide containing a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component, characterized by satisfying the following conditions a, b1 and c or a, b2 and c;

a) diamine residues derived from a dimer diamine composition comprising a dimer diamine in which primary aminomethyl groups or amino groups have been substituted for both terminal carboxylic acid groups of a dimer acid, the diamine residues being contained in an amount of 60 mol% or more based on the total diamine residues;

b1) a content ratio of a carbon atom derived from a 6-membered aromatic ring excluding a carbon atom derived from a 6-membered aromatic ring of the dimer diamine composition to a total content of all atoms in the polyimide is in a range of 12 to 40% by weight;

b2) a diamine residue derived from a diamine compound represented by the following general formula (a1) in an amount of 5 to 40 mol% based on the total diamine residues;

in the general formula (A1), Y and Z independently represent an alkyl group, alkoxy group, alkenyl group or alkynyl group having 1 to 6 carbon atoms, and the linking group X represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-CH₂-O-、-C(CH₃)₂A divalent group of-NH-or-CONH-, wherein m represents an integer of 1 to 4; wherein, when a plurality of linking groups X are contained in the molecule, they may be the same or different;

c) the weight average molecular weight is in the range of 5,000 to 200,000.

2. The polyimide according to claim 1, wherein when the condition a, the condition b1, and the condition c are satisfied, the following condition d is also satisfied;

d) a CM value, which is an index indicating the amount of a 6-membered aromatic ring contained in the polyimide, calculated on the basis of the following formula (i), is within a range of 3 to 38;

CM value (C/Mw) × 10⁴…(i)

Wherein C is a weight content of a carbon atom derived from a 6-membered aromatic ring excluding a carbon atom derived from a 6-membered aromatic ring of the dimer diamine composition with respect to a total content of all atoms in the polyimide, and Mw is a weight average molecular weight of the polyimide.

3. The polyimide according to claim 1, wherein when the condition a, the condition b1, and the condition c are satisfied, the following condition e is also satisfied;

e) the content ratio of the carbon atoms derived from the 6-membered aromatic ring excluding the carbon atoms derived from the 6-membered aromatic ring of the dimer diamine composition to the total content of all atoms in the total diamine components of the raw material is in the range of more than 0 and 32% by weight or less.

4. The polyimide according to claim 1, wherein when the condition a, the condition b1, and the condition c are satisfied, the following condition f is also satisfied;

f) a DM value, which is an index indicating the amount of a 6-membered aromatic ring derived from a diamine component contained in the polyimide, calculated on the basis of the following formula (ii), is in a range of more than 0 and 32 or less;

DM value (D/Mw) × 10⁴…(ii)

Wherein D is a weight content ratio of a carbon atom derived from a 6-membered aromatic ring excluding carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition with respect to a total content of all atoms in all diamine residues, and Mw is a weight average molecular weight of the polyimide.

5. The polyimide according to claim 1, wherein when the conditions a, b1, and c are satisfied, the total amount of diamine residues,

a diamine residue derived from the dimer diamine composition is contained in a range of 60 to 99 mol%,

a diamine residue derived from at least one diamine compound selected from diamine compounds represented by general formulae (B1) to (B7) in an amount of 1 to 40 mol%;

in the formulae (B1) to (B7), R₁Independently represents a C1-6 monovalent hydrocarbon group or an alkoxy group, and the linking group A independently represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-C(CH₃)₂A divalent radical of-NH-or-CONH-, n₁Independently represent an integer of 0 to 4; wherein a portion that overlaps with formula (B2) is removed from formula (B3), and a portion that overlaps with formula (B4) is removed from formula (B5).

6. The polyimide according to claim 1,

containing a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride represented by the following general formula (2) and/or general formula (3) in a total amount of 90 mol% or more based on the total amount of the acid anhydride residues;

in the general formula (2), X₁Represents a single bond or a divalent group selected from the group consisting of the following formula (3), Y₁The cyclic moiety represented represents a cyclic saturated hydrocarbon group forming a ring selected from a 4-membered ring, a 5-membered ring, a 6-membered ring, a 7-membered ring or an 8-membered ring;

-CO-，-SO₂-，-O-，

-C(CF₃)₂-，

-COO-or-COO-Z₁-OCO-

In the formula, Z₁represents-C₆H₄-、-(CH₂)_m1-or-CH₂-CH(-O-C(＝O)-CH₃)-CH₂-, m1 represents an integer of 1 to 20.

7. The polyimide according to claim 6, wherein the group X represented by the general formula (2) is contained in an amount of 10 to 90 mol% based on the total tetracarboxylic acid residues when the conditions a, b2 and c are satisfied₁A tetracarboxylic acid residue derived from a benzophenone tetracarboxylic dianhydride which is-CO-, containing 10 mol% or more of at least one tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride represented by the general formula (2) and/or the general formula (3), wherein the tetracarboxylic acid anhydride represented by the general formula (2) and/or the general formula (3) does not include the benzophenone tetracarboxylic dianhydride.

8. A crosslinked polyimide according to claim 1, wherein the polyimide contains a ketone group in a molecule,

the ketone group forms a crosslinked structure with an amino group of an amino compound having at least two primary amino groups as functional groups through a C ═ N bond.

9. An adhesive film comprising the polyimide according to claim 1 or the crosslinked polyimide according to claim 8.

10. The adhesive film according to claim 9, wherein when the polyimide satisfies the conditions a, b1, and c, the polyimide film has a dielectric loss tangent (Tan δ) at 10GHz measured by separating a dielectric resonator after humidity conditioning for 24 hours under constant temperature and humidity conditions of 23 ℃ and 50% RH₁) Has a relative dielectric constant (E) of 0.005 or less₁) Is 3.0 or less.

11. The adhesive film according to claim 9, wherein when the polyimide satisfies the conditions a, b1, and c, the polyimide is subjected to humidity conditioning under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH for 24 hours, and then the polyimide is separated from the dielectric resonator and measured for 20 hoursDielectric loss tangent (Tan. delta.) at GHz₂) Has a relative dielectric constant (E) of 0.005 or less₂) Is 3.0 or less.

12. The adhesive film according to claim 9, wherein when the polyimide satisfies the conditions a, b1, and c, the polyimide film has a dielectric loss tangent (Tan δ) at 10GHz measured by separating a dielectric resonator after humidity conditioning for 24 hours under constant temperature and humidity conditions of 23 ℃ and 50% RH₁) Dielectric loss tangent (Tan. delta.) at 20GHz₂) Difference of (Tan delta)₂-Tanδ₁) Is 0 or less.

13. The adhesive film according to claim 9, wherein when the polyimide satisfies the conditions a, b2, and c, the polyimide film has a dielectric loss tangent (Tan δ) at 10GHz measured by separating a dielectric resonator after humidity conditioning for 24 hours under constant temperature and humidity conditions of 23 ℃ and 50% RH₁) Less than 0.002, relative dielectric constant (E)₁) Is 3.0 or less.

14. The adhesive film according to claim 9, wherein when the polyimide satisfies the conditions a, b2, and c, the polyimide film has a dielectric loss tangent (Tan δ) at 20GHz, measured by separating a dielectric resonator after humidity conditioning for 24 hours under constant temperature and humidity conditions of 23 ℃ and 50% RH₂) Less than 0.002, relative dielectric constant (E)₂) Is 3.0 or less.

15. A laminate comprising a base material and an adhesive layer laminated on at least one surface of the base material, wherein the laminate is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

16. A cover film comprising a covering film layer and an adhesive layer laminated on the covering film layer, characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

17. A copper foil with resin, which is obtained by laminating an adhesive layer and a copper foil, and which is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

18. A metal-clad laminate having an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, characterized in that,

at least one layer of the insulating resin layer comprises the adhesive film according to claim 9.

19. A metal clad laminate having: an insulating resin layer; an adhesive layer laminated on at least one surface of the insulating resin layer; and a metal layer laminated on the insulating resin layer with the adhesive layer interposed therebetween, wherein the metal-clad laminated sheet is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

20. A metal clad laminate comprising:

a first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one side of the first metal layer;

a second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one side of the second metal layer; and

an adhesive layer disposed in contact with the first insulating resin layer and the second insulating resin layer, and laminated between the first single-sided metal clad laminate and the second single-sided metal clad laminate, wherein the metal clad laminate is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

21. A metal clad laminate comprising: a single-sided metal-clad laminate having an insulating resin layer and a metal layer laminated on one surface of the insulating resin layer; and an adhesive layer laminated on the other surface of the insulating resin layer, the adhesive layer including the adhesive film according to claim 9.

22. A circuit board obtained by wiring the metal layer of the metal-clad laminate according to claim 18.

23. A circuit substrate, comprising: a first substrate; a wiring layer laminated on at least one surface of the first base material; and an adhesive layer laminated on a surface of the first base material on the wiring layer side so as to cover the wiring layer, and the circuit board is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

24. A circuit substrate, comprising: a first substrate; a wiring layer laminated on at least one surface of the first base material; an adhesive layer laminated on the surface of the first base material on the wiring layer side so as to cover the wiring layer; and a second base material laminated on a surface of the adhesive layer opposite to the first base material, wherein the circuit board is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

25. A circuit substrate, comprising: a first substrate; an adhesive layer laminated on at least one surface of the first base material; a second base material laminated on a surface of the adhesive layer opposite to the first base material; and wiring layers laminated on surfaces of the first base material and the second base material opposite to the adhesive layer, respectively, and the circuit board is characterized in that,

the adhesive layer comprises the adhesive film according to claim 9.

26. A multilayer circuit substrate comprising: a laminate including a plurality of laminated insulating resin layers; and at least one or more wiring layers embedded in the laminated body, and is characterized in that,

at least one of the plurality of insulating resin layers is formed of an adhesive layer having adhesiveness and covering the wiring layer,

the adhesive layer comprises the adhesive film according to claim 9.

Background

In recent years, with the progress of downsizing, weight saving, and space saving of electronic devices, there has been an increasing demand for a Flexible Printed circuit board (FPC) that is thin and lightweight, has flexibility, and has excellent durability even when repeatedly bent. Since FPCs can be mounted in a limited space in a three-dimensional and high-density manner, their applications are expanding in parts such as a Hard Disk Drive (HDD), a Digital Video Disk (DVD), and a wiring, a cable, and a connector of a movable portion of an electronic device such as a smartphone.

As an embodiment of the FPC, an FPC having the following structure can be mentioned: a circuit pattern is formed on a polyimide film having excellent heat resistance and flexibility, and a cover film having an adhesive layer is bonded to the surface of the circuit pattern. Polyimide was used as a material for the adhesive layer of the cover film having such a structure. For example, it has been proposed to apply a crosslinked polyimide obtained by reacting a polyimide obtained from a diamine compound derived from a dimer acid as a raw material with an amino compound having at least two primary amino groups as functional groups to an adhesive layer of a coverlay film (for example, patent document 1).

Further, there are proposed: in a three-layer metal-clad laminate in which a metal-clad laminate serving as a material of a circuit board such as an FPC and the like is bonded with a wiring-processed metal layer and an insulating resin layer with an adhesive layer interposed therebetween, a polyimide containing a predetermined amount or more of diamine residues derived from dimer diamine in which both terminal carboxylic acid groups of dimer acid are substituted with primary aminomethyl groups or amino groups is applied to the adhesive layer (for example, patent document 2).

In addition to the above-described increase in density, the performance of the device is also increasing, and therefore, it is also necessary to cope with the increase in frequency of the transmission signal. When a high-frequency signal is transmitted, if transmission loss in a transmission path is large, problems such as loss of an electric signal and a long delay time of the signal occur. Therefore, in FPC, reduction of transmission loss is also important in the future. Therefore, there are proposed: in a circuit board including a polyimide insulating layer, a circuit wiring layer laminated on at least one surface of the polyimide insulating layer, and a coverlay laminated on the circuit wiring layer, the relationship between the thickness, dielectric constant, and dielectric loss tangent of the polyimide insulating layer and the coverlay is considered (for example, patent document 3).

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. 2013-1730

[ patent document 2] Japanese patent laid-open No. 2018-140544

[ patent document 3] Japanese patent laid-open No. 2016-192531

Disclosure of Invention

[ problems to be solved by the invention ]

As in patent documents 1 and 2, an adhesive layer using polyimide made from dimer diamine exhibits excellent adhesiveness, a low dielectric constant, and a low dielectric loss tangent, but further improvement in dielectric characteristics is required in order to cope with higher frequencies of transmission signals.

Accordingly, an object of the present invention is to further improve dielectric characteristics and more effectively reduce transmission loss of high-frequency signals in an adhesive layer using polyimide made of dimer diamine as a raw material.

[ means for solving problems ]

The present inventors have made extensive studies and as a result, have found that the dielectric characteristics of a polyimide can be improved by controlling the amount of aromatic rings contained in the polyimide using a dimer diamine as a raw material or by using a copolymerization composition of a dimer diamine and a diamine having a specific structure, and have completed the present invention.

The polyimide of the present invention is a polyimide containing a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component. The polyimide of the present invention satisfies the following conditions a, b1, and c, or a, b2, and c.

a) The dimer diamine composition contains 60 mol% or more of diamine residues derived from a dimer diamine composition comprising a dimer diamine in which primary aminomethyl groups or amino groups have been substituted for both terminal carboxylic acid groups of a dimer acid, relative to the total diamine residues.

b1) The content ratio of carbon atoms derived from the 6-membered aromatic ring (excluding carbon atoms derived from the 6-membered aromatic ring of the dimer diamine composition) to the total content of all atoms in the polyimide is in the range of 12 to 40% by weight.

b2) The diamine residue derived from a diamine compound represented by the following general formula (a1) is contained in a range of 5 to 40 mol% based on the total diamine residues.

[ solution 1]

In the general formula (A1), Y and Z independently represent an alkyl group, alkoxy group, alkenyl group or alkynyl group having 1 to 6 carbon atoms, and the linking group X represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-CH₂-O-、-C(CH₃)₂A divalent group of-NH-or-CONH-, and m represents an integer of 1 to 4. When a plurality of linking groups X are contained in the molecule, they may be the same or different.

c) The weight average molecular weight is in the range of 5,000 to 200,000.

The polyimide of the present invention may satisfy the following condition d when the above-mentioned conditions a, b1, and c are satisfied.

d) The CM value, which is an index indicating the amount of a 6-membered aromatic ring contained in the polyimide, is calculated on the basis of the following formula (i) and is within a range of 3 to 38.

CM value (C/Mw) × 10⁴…(i)

[ wherein C represents the weight content of carbon atoms derived from a 6-membered aromatic ring (excluding the carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) relative to the total content of all atoms in the polyimide, and Mw represents the weight average molecular weight of the polyimide ]

The polyimide of the present invention may satisfy the following condition e when the above conditions a, b1, and c are satisfied.

e) The content ratio of carbon atoms derived from the 6-membered aromatic ring (excluding carbon atoms derived from the 6-membered aromatic ring of the dimer diamine composition) to the total content of all atoms in all diamine components in the raw material is in the range of more than 0 and 32% by weight or less.

The polyimide of the present invention may satisfy the following condition f when the above-described conditions a, b1, and c are satisfied.

f) The DM value, which is an index indicating the amount of the 6-membered aromatic ring derived from the diamine component contained in the polyimide, calculated based on the following formula (ii), is in a range of more than 0 and 32 or less.

DM value (D/Mw) × 10⁴…(ii)

[ wherein D represents the weight content of carbon atoms derived from a 6-membered aromatic ring (excluding carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) relative to the total content of all atoms in all diamine residues, and Mw represents the weight average molecular weight of polyimide ]

The polyimide of the present invention may contain diamine residues derived from the dimer diamine composition in a range of 60 to 99 mol% based on the total amount of the diamine residues when the conditions a, b1, and c are satisfied. In this case, the diamine residue derived from at least one diamine compound selected from the group consisting of diamine compounds represented by the following general formula (B1) to general formula (B7) may be contained in the range of 1 mol% to 40 mol%.

[ solution 2]

In the formulae (B1) to (B7), R₁Independently represents a C1-6 monovalent hydrocarbon group or an alkoxy group, and the linking group A independently represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-C(CH₃)₂A divalent radical of-NH-or-CONH-, n₁Independently represent an integer of 0 to 4. Wherein a portion that overlaps with formula (B2) is removed from formula (B3), and a portion that overlaps with formula (B4) is removed from formula (B5).

The polyimide of the present invention may contain 90 mol% or more of tetracarboxylic acid residues derived from tetracarboxylic acid anhydrides represented by the following general formula (2) and/or general formula (3) in total based on the total amount of the acid anhydride residues.

[ solution 3]

In the general formula (2), X₁Represents a single bond or a divalent group selected from the group consisting of the following formula (3), Y₁The cyclic moiety represented represents a cyclic saturated hydrocarbon group forming a ring selected from a 4-membered ring, a 5-membered ring, a 6-membered ring, a 7-membered ring or an 8-membered ring.

[ solution 4]

In the formula, Z₁represents-C₆H₄-、-(CH₂)_m1-or-CH₂-CH(-O-C(＝O)-CH₃)-CH₂-, m1 represents an integer of 1 to 20.

The polyimide of the present invention may contain the group X in the general formula (2) in an amount of 10 to 90 mol% based on the total tetracarboxylic acid residues when the conditions a, b2, and c are satisfied₁The tetracarboxylic acid residue derived from benzophenone tetracarboxylic dianhydride which is-CO-may contain 10 mol% or more of at least one tetracarboxylic acid residue derived from tetracarboxylic acid anhydride represented by the general formula (2) and/or the general formula (3) except the benzophenone tetracarboxylic dianhydride.

The crosslinked polyimide of the present invention contains a ketone group in the molecule,

the ketone group forms a crosslinked structure with an amino group of an amino compound having at least two primary amino groups as functional groups through a C ═ N bond.

The adhesive film of the present invention contains the polyimide or the crosslinked polyimide.

When the polyimide satisfies the conditions a, b1, and c, the adhesive film of the present invention is subjected to humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH, and then passed through a separation medium resonator (Sp)Dielectric loss tangent (Tan. delta. delta.) at 10GHz as determined by the litpost Dielectric Resonator, SPDR₁) Can be 0.005 or less, and has a relative dielectric constant (E)₁) May be 3.0 or less.

When the polyimide satisfies the conditions a, b1, and c, the adhesive film of the present invention has a dielectric loss tangent (Tan δ) at 20GHz measured by separating a dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₂) Can be 0.005 or less, and has a relative dielectric constant (E)₂) May be 3.0 or less.

When the polyimide satisfies the conditions a, b1, and c, the adhesive film of the present invention has a dielectric loss tangent (Tan δ) at 10GHz measured by separating a dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₁) Dielectric loss tangent (Tan. delta.) at 20GHz₂) Difference of (Tan delta)₂-Tanδ₁) May be 0 or less.

When the polyimide satisfies the conditions a, b2, and c, the adhesive film of the present invention has a dielectric loss tangent (Tan δ) at 10GHz measured by separating a dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₁) Less than 0.002, relative dielectric constant (E)₁) May be 3.0 or less.

When the polyimide satisfies the conditions a, b2, and c, the adhesive film of the present invention has a dielectric loss tangent (Tan δ) at 20GHz measured by separating a dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₂) Less than 0.002, relative dielectric constant (E)₂) May be 3.0 or less.

The laminate of the present invention comprises a base material and an adhesive layer laminated on at least one surface of the base material, wherein in the laminate,

the adhesive layer includes any of the adhesive films.

The cover film of the present invention has a covering film layer and an adhesive layer laminated on the covering film layer, and in the cover film,

the adhesive layer includes any of the adhesive films.

The resin-coated copper foil of the present invention is obtained by laminating an adhesive layer and a copper foil, wherein in the resin-coated copper foil,

the adhesive layer includes any of the adhesive films.

The metal-clad laminate of the present invention has an insulating resin layer and a metal layer laminated on at least one surface of the insulating resin layer, and in the metal-clad laminate,

at least one of the insulating resin layers includes any one of the adhesive films.

Another aspect of the present invention provides a metal-clad laminate comprising: an insulating resin layer; an adhesive layer laminated on at least one surface of the insulating resin layer; and a metal layer laminated on the insulating resin layer with the adhesive layer interposed therebetween, wherein the metal-clad laminated sheet,

the adhesive layer includes any of the adhesive films.

A metal-clad laminate according to still another aspect of the present invention includes:

a first single-sided metal-clad laminate having a first metal layer and a first insulating resin layer laminated on at least one side of the first metal layer;

a second single-sided metal-clad laminate having a second metal layer and a second insulating resin layer laminated on at least one side of the second metal layer; and

and an adhesive layer that is disposed in contact with the first insulating resin layer and the second insulating resin layer, and that is laminated between the first single-sided metal-clad laminate and the second single-sided metal-clad laminate. In the metal-clad laminate of the present invention, the adhesive layer includes any of the adhesive films.

A metal-clad laminate according to still another aspect of the present invention includes: a single-sided metal-clad laminate having an insulating resin layer and a metal layer laminated on one surface of the insulating resin layer; and an adhesive layer laminated on the other surface of the insulating resin layer, the adhesive layer including any of the adhesive films.

The circuit board of the present invention is obtained by wiring the metal layer of the metal-clad laminate.

A circuit board according to another aspect of the present invention includes: a first substrate; a wiring layer laminated on at least one surface of the first base material; and an adhesive layer laminated on a surface of the first base material on the wiring layer side so as to cover the wiring layer, wherein the circuit board has a first surface and a second surface,

the adhesive layer includes any of the adhesive films.

A circuit board according to still another aspect of the present invention includes: a first substrate; a wiring layer laminated on at least one surface of the first base material; an adhesive layer laminated on the surface of the first base material on the wiring layer side so as to cover the wiring layer; and a second base material laminated on a surface of the adhesive layer opposite to the first base material, wherein the circuit board is provided with a first adhesive layer,

the adhesive layer includes any of the adhesive films.

A circuit board according to still another aspect of the present invention includes: a first substrate; an adhesive layer laminated on at least one surface of the first base material; a second base material laminated on a surface of the adhesive layer opposite to the first base material; and wiring layers laminated on surfaces of the first base material and the second base material opposite to the adhesive layer, respectively, wherein the circuit board includes a first wiring layer and a second wiring layer,

the adhesive layer includes any of the adhesive films.

The multilayer circuit board of the present invention includes: a laminate including a plurality of laminated insulating resin layers; and at least one or more wiring layers embedded in the laminated body, wherein the multilayer circuit board has a plurality of layers,

at least one of the plurality of insulating resin layers is formed of an adhesive layer having adhesiveness and covering the wiring layer,

the adhesive layer includes any of the adhesive films.

[ Effect of the invention ]

The polyimide of the present invention has excellent adhesiveness, a low dielectric constant and a low dielectric loss tangent, and can effectively suppress transmission loss in high-frequency signal transmission by controlling the amount of aromatic rings contained in a polyimide prepared from a dimer diamine or by using a copolymer composition of a dimer diamine and a diamine having a specific structure. Therefore, the polyimide of the present invention can effectively reduce transmission loss when applied to a circuit board or the like for transmitting a high-frequency signal having a GHz band (for example, 1GHz to 20 GHz).

Drawings

Fig. 1 is a schematic diagram showing a structure of a cross section of a laminate according to an embodiment of the present invention.

Fig. 2 is a schematic diagram showing a structure of a cross section of a metal-clad laminate according to an embodiment of the present invention.

Fig. 3 is a schematic diagram showing a structure of a cross section of a metal-clad laminate according to another embodiment of the present invention.

Fig. 4 is a schematic diagram showing a cross-sectional structure of a metal-clad laminate according to still another embodiment of the present invention.

Fig. 5 is a schematic diagram showing a cross-sectional structure of a circuit board according to an embodiment of the present invention.

Fig. 6 is a schematic diagram showing a cross-sectional structure of a circuit board according to another embodiment of the present invention.

Fig. 7 is a schematic diagram showing a cross-sectional structure of a circuit board according to still another embodiment of the present invention.

Fig. 8 is a schematic diagram showing a cross-sectional structure of a multilayer circuit board according to an embodiment of the present invention.

FIG. 9 is a drawing schematically showing the relationship between the aromatic ring concentration and the dielectric loss tangent of an adhesive polyimide.

[ description of symbols ]

10: base material

11: a first substrate

12: second base material

20: adhesive layer

30. 33, 34: insulating resin layer

31: a first insulating resin layer

32: second insulating resin layer

41: a first single-side metal-clad laminate

42: second single-side metal-clad laminate

50: wiring layer

M: metal layer

M1: a first metal layer

M2: second metal layer

100: laminated body

101: three-layer metal-clad laminated plate

102: laminated metal-clad laminate

103: metal-clad laminate with adhesive layer

200. 201, 202: circuit board

203: multilayer circuit board

Detailed Description

Embodiments of the present invention will be described with reference to the accompanying drawings.

The polyimide according to an embodiment of the present invention is an adhesive polyimide. Hereinafter, the polyimide of the present embodiment may be referred to as "adhesive polyimide". The adhesive polyimide contains a tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride component and a diamine residue derived from a diamine component. In the present invention, "tetracarboxylic acid residue" represents a tetravalent group derived from tetracarboxylic dianhydride, and "diamine residue" represents a divalent group derived from a diamine compound. When the tetracarboxylic anhydride and the diamine compound as raw materials are reacted in substantially equimolar amounts, the kinds and molar ratios of the tetracarboxylic acid residue and the diamine residue contained in the polyimide and the kinds and molar ratios of the raw materials can be made to substantially correspond to each other.

In the present invention, the term "polyimide" refers to resins containing a polymer having an imide group in its molecular structure, such as polyamideimide, polyetherimide, polyesterimide, polysiloxane imide and polybenzimidazole imide, in addition to polyimide.

The adhesive polyimide of the present embodiment satisfies the following condition a, condition b1, and condition c, or condition a, condition b2, and condition c. The raw material monomers, tetracarboxylic acid residues and diamine residues of the adhesive polyimide will be described in detail below.

Condition a)

Diamine residues derived from a dimer diamine composition comprising a dimer diamine in which primary aminomethyl groups or amino groups have been substituted for both terminal carboxylic acid groups of a dimer acid are contained in an amount of 60 mol% or more based on the total diamine residues:

the relative dielectric constant and dielectric loss tangent of the polyimide can be reduced by setting the content of diamine residues derived from the dimer diamine composition to 60 mol% or more, preferably in the range of 60 to 99 mol%, more preferably in the range of 60 to 95 mol%, even more preferably in the range of 65 to 95 mol%, and most preferably in the range of 70 to 90 mol%, based on the total diamine residues. When the content of the diamine residue derived from the dimer diamine composition is less than 60 mol%, the relative permittivity and dielectric loss tangent are likely to increase due to the relative increase in the polar groups contained in the polyimide. When the content of diamine residues derived from the dimer diamine composition exceeds 99 mol% based on the total diamine residues, the mobility of the molecular chain of the polyimide is excessively increased, and the dielectric loss tangent may be increased. In addition, by containing the dimer diamine in the above amount, the dielectric characteristics of the polyimide can be improved, and at the same time, the thermocompression bonding characteristics can be improved by lowering the glass transition temperature (lowering Tg) of the polyimide and the internal stress can be relaxed by lowering the elastic modulus.

Condition b1)

The content ratio of carbon atoms derived from a 6-membered aromatic ring (excluding carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) to the total content of all atoms in the polyimide is in the range of 12 to 40% by weight:

the content of carbon atoms derived from a 6-membered aromatic ring means the content of aromatic rings (aromatic ring concentration) contained in the adhesive polyimide. When the content of carbon atoms derived from the 6-membered aromatic ring is in the range of 12 to 40 wt%, the interaction between the aromatic rings in the polyimide restricts the movement of molecules, and the effect of reducing the dielectric loss tangent is exhibited. If the content of the carbon atom derived from the 6-membered aromatic ring is less than 12% by weight, the movement of the molecular chain of the polyimide cannot be suppressed, and thus the dielectric loss tangent becomes high. When the content of the carbon atom derived from the 6-membered aromatic ring exceeds 40% by weight, the polarity of the molecule becomes large and the dielectric loss tangent becomes high. The content of carbon atoms derived from the 6-membered aromatic ring is preferably in the range of 17 to 38% by weight, more preferably in the range of 20 to 30% by weight.

Condition b2)

A diamine residue derived from a diamine compound represented by the general formula (a1) is contained in a range of 5 mol% or more and 40 mol% or less with respect to the total diamine residues:

the relative dielectric constant and the dielectric loss tangent of the polyimide can be reduced by setting the content of the diamine residue derived from the diamine compound represented by the general formula (a1) to be in the range of 5 to 40 mol%, preferably in the range of 10 to 30 mol%, based on the total diamine residues. When the content of the diamine residue derived from the diamine compound represented by the general formula (a1) is less than 5 mol%, the mobility of the molecular chain of the polyimide is excessively increased, and the dielectric loss tangent may be increased. When the content of the diamine residue derived from the diamine compound represented by the general formula (a1) is more than 40 mol% based on the total diamine residues, the polarity of the molecular chain of the polyimide may be excessively increased, and the dielectric loss tangent may be increased.

Condition c)

The weight average molecular weight is in the range of 5,000-200,000:

when the weight average molecular weight of the adhesive polyimide is less than 5,000, embrittlement is likely to occur at the time of film formation. On the other hand, when the weight average molecular weight exceeds 200,000, the viscosity becomes high when varnish is prepared, and thickness unevenness is likely to occur when coating.

The weight average molecular weight of the adhesive polyimide is preferably within a range of 10,000 to 100,000, more preferably within a range of 10,000 to 60,000, and still more preferably within a range of 20,000 to 55,000. When the weight average molecular weight is less than 10,000, the highly polar terminals in the polyimide molecular chain increase, and the relative dielectric constant and the dielectric loss tangent may easily increase. When the weight average molecular weight exceeds 100,000, the molecular chain length becomes long and it becomes difficult to obtain an ordered structure, and therefore the relative dielectric constant and the dielectric loss tangent may easily increase.

The polyimide of the present embodiment preferably satisfies one or more of the following conditions d, e, and f when the conditions a, b1, and c are satisfied.

Condition d)

The CM value, which is an index indicating the amount of a 6-membered aromatic ring contained in the polyimide, is calculated on the basis of the following equation (i) and is within a range of 3 to 38:

CM value (C/Mw) × 10⁴…(i)

[ wherein C represents the weight content of carbon atoms derived from a 6-membered aromatic ring (excluding the carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) relative to the total content of all atoms in the polyimide, and Mw represents the weight average molecular weight of the polyimide ]

When the CM value is less than 3, the aromatic ring concentration is low, so that the molecular mobility is high and the dielectric loss tangent is high. On the other hand, if the CM value exceeds 38, the aromatic ring concentration becomes excessive, and the polarity increases, and the dielectric loss tangent increases.

Condition e)

The weight content ratio of carbon atoms derived from the 6-membered aromatic ring (excluding carbon atoms derived from the 6-membered aromatic ring of the dimer diamine composition) to the total content of all atoms in all diamine components of the raw material is in the range of more than 0 and 32% by weight or less:

in the adhesive polyimide, the content of the aromatic ring is controlled within an appropriate range, so that the interaction between the aromatic rings in the polyimide restricts the movement of the molecule, thereby exhibiting the effect of reducing the dielectric loss tangent. In order to achieve the above object, it is effective that the content of the carbon atoms derived from the 6-membered aromatic ring with respect to the total content of carbon atoms is also within the above range with respect to the diamine component of the raw material. When the content of carbon atoms derived from a 6-membered aromatic ring in the total diamine components in the raw materials exceeds 32% by weight, the polarity of the obtained polyimide molecule becomes large and the dielectric loss tangent becomes high.

Condition f)

The DM value, which is an index indicating the amount of the 6-membered aromatic ring derived from the diamine component contained in the polyimide, calculated based on the following formula (ii), is in the range of more than 0 and 32 or less:

DM value (D/Mw) × 10⁴…(ii)

[ wherein D represents the weight content of carbon atoms derived from a 6-membered aromatic ring (excluding carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) relative to the total content of all atoms in all diamine residues, and Mw represents the weight average molecular weight of polyimide ]

For the same reason as in condition e, it is effective to set the content of the carbon atom derived from the 6-membered aromatic ring in the diamine residue in the above range with respect to the total content of all atoms in the polyimide.

(acid anhydride)

The adhesive polyimide may be a tetracarboxylic anhydride generally used for thermoplastic polyimides, but is preferably a tetracarboxylic anhydride containing not less than 90 mol% of the total of tetracarboxylic anhydrides represented by the following general formula (2) and/or (3) based on the total amount of all tetracarboxylic anhydride components. In other words, the adhesive polyimide preferably contains 90 mol% or more of tetracarboxylic acid residues derived from tetracarboxylic acid anhydrides represented by the following general formula (2) and/or general formula (3) in total based on the total tetracarboxylic acid residues. It is preferable that the flexibility and heat resistance of the adhesive polyimide be compatible with each other by containing 90 mol% or more of a tetracarboxylic acid residue derived from a tetracarboxylic anhydride represented by the following general formula (2) and/or general formula (3) in total based on the total tetracarboxylic acid residues. If the total amount of tetracarboxylic acid residues derived from the tetracarboxylic acid anhydride represented by the following general formula (2) and/or general formula (3) is less than 90 mol%, the solvent solubility of the adhesive polyimide tends to decrease.

[ solution 5]

In the general formula (2), X₁Represents a single bond or a divalent group selected from the group consisting of the following formula (3), Y₁The cyclic moiety represented represents a cyclic saturated hydrocarbon group forming a ring selected from a 4-membered ring, a 5-membered ring, a 6-membered ring, a 7-membered ring or an 8-membered ring.

[ solution 6]

In the formula, Z₁represents-C₆H₄-、-(CH₂)_m1-or-CH₂-CH(-O-C(＝O)-CH₃)-CH₂-, m1 represents an integer of 1 to 20.

Examples of the tetracarboxylic anhydride represented by the general formula (2) include: 3,3',4,4' -biphenyltetracarboxylic dianhydride (3,3',4,4' -biphenyltetracarboxylic dianhydride, BPDA), 3,3',4,4' -benzophenonetetracarboxylic dianhydride (3,3',4,4' -benzophenonetetracarboxylic dianhydride, BTDA), 2,3',3,4' -benzophenonetetracarboxylic dianhydride, 2',3,3' -benzophenonetetracarboxylic dianhydride, 2,3, 4' -benzophenonetetracarboxylic dianhydride, 2,3,3',4' -benzophenonetetracarboxylic dianhydride, 3,3',4,4' -diphenylsulfonetetracarboxylic dianhydride (3,3',4,4' -diphenylsulfonatetracarboxylic dianhydride, DSDA), 4,4' -oxydiphthalic anhydride (4,4' -oxydiphthalic dianhydride, ODPA), 4,4' - (hexafluoroisopropylidene) diphthalic acid anhydride (4,4' - (phthalic anhydride) phthalic anhydride, 6FDA), 2-bis [4- (3,4-dicarboxyphenoxy) phenyl ] propane dianhydride (2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl ] propane dianhydride, BPADA), p-phenylene bis (trimellitic acid monoester) anhydride (TAHQ), ethylene glycol bis trimellitic anhydride (TMEG), and the like. Among these, 3',4,4' -Benzophenone Tetracarboxylic Dianhydride (BTDA) is particularly preferable. In the case of using BTDA, the carbonyl group (ketone group) present in the molecular skeleton contributes to the adhesiveness, and thus the adhesiveness of the adhesive polyimide can be improved. BTDA has a problem that a ketone group present in a molecular skeleton reacts with an amino group of an amino compound to be crosslinked, which will be described later, to form a C ═ N bond, and thus an effect of improving heat resistance is easily exhibited. From this viewpoint, it is preferable that the BTDA-derived tetracarboxylic acid residue is contained in an amount of preferably 50 mol% or more, more preferably 60 mol% or more, based on the total tetracarboxylic acid residues.

Examples of the tetracarboxylic anhydride represented by the general formula (3) include: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride, 1,2,3, 4-cyclopentanetetracarboxylic dianhydride, 1,2,4, 5-cyclohexanetetracarboxylic dianhydride, 1,2,4, 5-cycloheptanetetracarboxylic dianhydride, 1,2,5, 6-cyclooctanetetracarboxylic dianhydride, etc.

Here, the adhesive polyimide preferably satisfies the following condition g for the acid anhydride when the conditions a, b2, and c are satisfied.

Condition g)

The group X represented by the general formula (2) is contained in an amount of 10 to 90 mol% based on the total tetracarboxylic acid residues₁A tetracarboxylic acid residue derived from a benzophenone tetracarboxylic dianhydride which is-CO-, and which contains 10 mol% or more of at least one tetracarboxylic acid residue derived from a tetracarboxylic acid anhydride represented by the general formula (2) and/or the general formula (3) excluding the benzophenone tetracarboxylic dianhydride:

by containing a tetracarboxylic acid residue derived from benzophenone tetracarboxylic dianhydride in a total amount of 10 to 90 mol% based on the total tetracarboxylic acid residues, both flexibility and heat resistance of the adhesive polyimide can be easily achieved, and the ketone group contributes to the adhesiveness, so that the adhesiveness of the adhesive polyimide can be improved. If the amount of the tetracarboxylic acid residue derived from benzophenone tetracarboxylic dianhydride is less than 10 mol% based on the total amount of the tetracarboxylic acid residues, the amount of the ketone group as a crosslinking point decreases, and solder heat resistance may not be exhibited. Further, when the content of the tetracarboxylic acid residue derived from benzophenone tetracarboxylic dianhydride exceeds 90 mol% with respect to the total tetracarboxylic acid residues, the diamine residue derived from the diamine compound reacts with the ketone group derived from benzophenone tetracarboxylic dianhydride, whereby the solubility is significantly reduced. That is, the upper limit value is set to 90 mol% or less because a ketone group present in a molecular skeleton of benzophenone tetracarboxylic dianhydride reacts with an amino group derived from a diamine compound to form a C ═ N bond, and the resulting polymer is increased in molecular weight and gelled. Further, as the benzophenonetetracarboxylic dianhydride, any of 3,3',4,4' -benzophenonetetracarboxylic dianhydride, 2,3',3,4' -benzophenonetetracarboxylic dianhydride, 2',3,3' -benzophenonetetracarboxylic dianhydride and 2,3,3',4' -benzophenonetetracarboxylic dianhydride can be used.

On the other hand, the tetracarboxylic anhydride represented by the general formula (2) and/or the general formula (3) (excluding the benzophenone tetracarboxylic dianhydride) does not have a functional group that reacts with a diamine residue derived from a diamine compound, and therefore, when used in combination with the benzophenone tetracarboxylic dianhydride, the effect of suppressing a decrease in solvent solubility and improving solder heat resistance can be obtained.

Therefore, when the conditions a, b2, and c are satisfied, the storage stability can be improved by setting the content of the tetracarboxylic acid residue derived from benzophenone tetracarboxylic dianhydride to a range of 10 mol% or more and 90 mol% or less, preferably 10 mol% or more and 50 mol% or less, relative to the total tetracarboxylic acid residues, and setting the content of at least one of the tetracarboxylic acid residues derived from tetracarboxylic acid anhydrides represented by the general formula (2) and/or the general formula (3) (excluding benzophenone tetracarboxylic dianhydride) to a range of 10 mol% or more, preferably 10 mol% or more and 50 mol% or less.

The adhesive polyimide may contain a tetracarboxylic acid residue derived from an acid anhydride other than the tetracarboxylic acid anhydrides represented by the general formulae (2) and (3) in a range not to impair the effects of the present invention. Examples of such tetracarboxylic acid residues include, but are not particularly limited to, pyromellitic dianhydride, 2,3',3,4' -biphenyltetracarboxylic acid dianhydride, 2,3',3,4' -diphenyl ether tetracarboxylic acid dianhydride, bis (2, 3-dicarboxyphenyl) ether dianhydride, 3,3',4,4' -p-terphenyltetracarboxylic acid dianhydride, 2,3,3',4' -p-terphenyltetracarboxylic acid dianhydride or 2,2',3,3' -p-terphenyltetracarboxylic acid dianhydride, 2-bis (2, 3-dicarboxyphenyl) -propane dianhydride or 2,2-bis (3, 4-dicarboxyphenyl) -propane dianhydride, bis (2, 3-dicarboxyphenyl) methane dianhydride or bis (3, 4-dicarboxyphenyl) methane dianhydride, bis (2, 3-dicarboxyphenyl) sulfone dianhydride or bis (3, 4-dicarboxyphenyl) sulfone dianhydride, 1-bis (2, 3-dicarboxyphenyl) ethane dianhydride or 1, 1-bis (3, 4-dicarboxyphenyl) ethane dianhydride, 1,2,7, 8-phenanthrene-tetracarboxylic dianhydride, 1,2,6, 7-phenanthrene-tetracarboxylic dianhydride or 1,2,9, 10-phenanthrene-tetracarboxylic dianhydride, 2,3,6, 7-anthracenetetracarboxylic dianhydride, 2-bis (3, 4-dicarboxyphenyl) tetrafluoropropane dianhydride, 1,2,5, 6-naphthalenetetracarboxylic dianhydride, 1,4,5, 8-naphthalenetetracarboxylic dianhydride, 2,3,6, 7-naphthalenetetracarboxylic dianhydride, 4, 8-dimethyl-1, 2,3,5,6, 7-hexahydronaphthalene-1, 2,5, 6-tetracarboxylic dianhydride, 2, 6-dichloronaphthalene-1, 4,5, 8-tetracarboxylic dianhydride or 2, 7-dichloronaphthalene-1, 4,5, 8-tetracarboxylic dianhydride, 2,3,6,7- (or 1,4,5,8-) tetrachloronaphthalene-1, 4,5,8- (or 2,3,6,7-) tetracarboxylic dianhydride, 2,3,8, 9-perylene-tetracarboxylic dianhydride, 3,4,9, 10-perylene-tetracarboxylic dianhydride, 4,5,10, 11-perylene-tetracarboxylic dianhydride or 5,6,11, 12-perylene-tetracarboxylic dianhydride, pyrazine-2, 3,5, 6-tetracarboxylic dianhydride, pyrrolidine-2, 3,4, 5-tetracarboxylic dianhydride, thiophene-2, 3,4, tetracarboxylic acid residues derived from aromatic tetracarboxylic acid dianhydrides such as 5-tetracarboxylic acid dianhydride and 4,4' -bis (2, 3-dicarboxyphenoxy) diphenylmethane dianhydride.

(diamine)

The adhesive polyimide may be produced from a diamine compound, which is generally used for thermoplastic polyimides, without any particular limitation, but may be produced from a dimer diamine composition containing 60 mol% or more of a dimer diamine in which both terminal carboxylic acid groups of the dimer acid are substituted with primary aminomethyl groups or amino groups, as a main component, based on the total diamine components. In other words, as described in condition a, the adhesive polyimide contains 60 mol% or more of diamine residues derived from a dimer diamine composition containing, as a main component, a dimer diamine in which both terminal carboxylic acid groups of a dimer acid are substituted with primary aminomethyl groups or amino groups, relative to the total diamine residues.

The dimer diamine composition is a purified product containing the following component (a) as a main component and having controlled amounts of the component (b) and the component (c).

(a) A dimer diamine;

the dimer diamine as component (a) means that the two terminal carboxylic acid groups (-COOH) of the dimer acid are substituted with primary aminomethyl (-CH)₂-NH₂) Or amino (-NH)₂) Substituted diamines. Dimer acid is a known dibasic acid obtained by intermolecular polymerization of unsaturated fatty acids, and its industrial production process is generally standardized in the industry, and is obtained by dimerizing an unsaturated fatty acid having 11 to 22 carbon atoms using a clay catalyst or the like. The commercially available dimer acid contains a dibasic acid having 36 carbon atoms obtained by dimerizing an unsaturated fatty acid having 18 carbon atoms such as oleic acid, linoleic acid, linolenic acid, etc., as a main component, and contains a monomer acid (having 18 carbon atoms), a trimer acid (having 54 carbon atoms), and other polymerized fatty acids having 20 to 54 carbon atoms in an arbitrary amount depending on the degree of purification. In addition, although a double bond remains after the dimerization reaction, in the present invention, a compound which further undergoes a hydrogenation reaction to reduce the degree of unsaturation is also included in the dimer acid. The dimer diamine as the component (a) can be defined as a diamine compound obtained by substituting a terminal carboxylic acid group of a dibasic acid compound having 18 to 54 carbon atoms, preferably 22 to 44 carbon atoms, with a primary aminomethyl group or an amino group.

As a feature of dimer diamine, a property derived from the skeleton of dimer acid can be imparted. That is, the dimer diamine is an aliphatic group of a macromolecule having a molecular weight of about 560 to 620, and thus can increase the molar volume of the macromolecule and relatively reduce the polar group of the polyimide. It is considered that such dimer acid-based diamine is characterized to contribute to suppression of lowering of heat resistance of polyimide and to reduction of dielectric constant and dielectric loss tangent to improve dielectric characteristics. Further, since the polyimide contains two freely movable hydrophobic chains having 7 to 9 carbon atoms and two chain aliphatic amino groups having a length close to 18 carbon atoms, not only flexibility can be imparted to the polyimide, but also the polyimide can have an asymmetric chemical structure or a non-planar chemical structure, and thus it is considered that the low dielectric constant of the polyimide can be achieved.

The dimer diamine composition is preferably a dimer diamine composition comprising: the dimer diamine content as component (a) is increased to 96% by weight or more, preferably 97% by weight or more, and more preferably 98% by weight or more by a purification method such as molecular distillation. By setting the content of dimer diamine as the component (a) to 96% by weight or more, the spread of the molecular weight distribution of polyimide can be suppressed. Further, it is preferable that the dimer diamine as the component (a) is contained in the whole dimer diamine composition (100% by weight) if the technology is feasible. Further, the dimer diamine composition may contain a dimer diamine having a 6-membered aromatic ring as a molecular skeleton. In the polyimide of the present embodiment, the ratio of the aromatic monomer directly bonded to the imide bond site is focused on and is controlled, but in the dimer diamine having a 6-membered aromatic ring, the 6-membered aromatic ring is an imide bond with an aliphatic chain having a length of 7 or more carbon atoms interposed therebetween, and therefore, the 6-membered aromatic ring in the polyimide of the present embodiment is not controlled. Therefore, the conditions b1, d, e, and f for the adhesive polyimide are exclusive of the 6-membered aromatic ring derived from the dimer diamine. Further, the ratio of the aromatic ring derived from the dimer diamine is preferably 20 mol or less based on 1mol of the amino group by quantification by 1H-Nuclear Magnetic Resonance (NMR).

(b) A monoamine compound obtained by substituting a terminal carboxylic acid group of a monoacid compound having a carbon number within a range of 10 to 40 with a primary aminomethyl group or an amino group;

the monoacid compound having a carbon number within a range of 10 to 40 is a mixture of a monoacid unsaturated fatty acid having a carbon number within a range of 10 to 20 derived from a raw material of a dimer acid and a monoacid compound having a carbon number within a range of 21 to 40, which is a byproduct in the production of the dimer acid. The monoamine compound is obtained by substituting a terminal carboxylic acid group of these monoacid compounds with a primary aminomethyl group or an amino group.

The monoamine compound as the component (b) is a component for suppressing an increase in the molecular weight of the polyimide. At the time of polymerization of polyamic acid or polyimide, the monofunctional amino group of the monoamine compound reacts with the terminal acid anhydride group of polyamic acid or polyimide, thereby capping the terminal acid anhydride group, thereby suppressing increase in molecular weight of polyamic acid or polyimide.

(c) An amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group with a carbon number in the range of 41 to 80 with a primary aminomethyl group or an amino group (excluding the dimer diamine);

the polybasic acid compound having a hydrocarbon group with a carbon number in the range of 41 to 80 is a polybasic acid compound mainly composed of a ternary acid compound having a carbon number in the range of 41 to 80, which is a by-product in the production of a dimer acid. Further, polymerized fatty acid other than the dimer acid having 41 to 80 carbon atoms may be contained. The amine compound is obtained by substituting a terminal carboxylic acid group of these polybasic acid compounds with a primary aminomethyl group or an amino group.

The amine compound as the component (c) is a component which promotes the increase in the molecular weight of the polyimide. The molecular weight of polyimide is drastically increased by reacting a trifunctional or higher amino group mainly composed of a triamine derived from a trimer acid with a terminal acid anhydride group of polyamic acid or polyimide. Further, the amine compound derived from a polymerized fatty acid other than the dimer acid having 41 to 80 carbon atoms also increases the molecular weight of the polyimide, which causes gelation of the polyamic acid or polyimide.

In the case of quantifying each component by measurement using Gel Permeation Chromatography (GPC), in order to easily confirm the peak start (peak start), peak top (peak top) and peak end (peak end) of each component of the dimer diamine composition, a sample obtained by treating the dimer diamine composition with acetic anhydride and pyridine was used, and cyclohexanone was used as an internal standard substance. Using the samples prepared as described above, each component was quantified by area percentage of the GPC chromatogram. The peak start and peak end of each component are minimum values of each peak curve, and the area percentage of the chromatogram can be calculated based on the minimum values.

The dimer diamine composition preferably contains the component (b) and the component (c) in a total amount of 4% or less, preferably less than 4%, in terms of area percentage of a chromatogram obtained by GPC measurement. By setting the total of the component (b) and the component (c) to 4% or less, the spread of the molecular weight distribution of the polyimide can be suppressed.

The area percentage of the chromatogram of component (b) is preferably 3% or less, more preferably 2% or less, and still more preferably 1% or less. By setting the molar ratio in this range, the molecular weight of the polyimide can be suppressed from decreasing, and the molar ratio of the tetracarboxylic anhydride component to the diamine component can be expanded. The component (b) may not be contained in the dimer diamine composition.

The area percentage of the chromatogram of component (c) is preferably 2% or less, and more preferably 1.8% or less, and still more preferably 1.5% or less. By setting the molecular weight in such a range, a sharp increase in the molecular weight of the polyimide can be suppressed, and an increase in the dielectric loss tangent at a wide range of frequencies of the resin film can be suppressed. The component (c) may not be contained in the dimer diamine composition.

When the ratio (b/c) of the area percentages of the chromatograms of the component (b) and the component (c) is 1 or more, the molar ratio of the tetracarboxylic anhydride component and the diamine component (tetracarboxylic anhydride component/diamine component) is preferably 0.97 or more and less than 1.0, and by setting such a molar ratio, it is easier to control the molecular weight of the polyimide.

When the ratio (b/c) of the area percentages of the chromatograms of the component (b) and the component (c) is less than 1, the molar ratio of the tetracarboxylic anhydride component and the diamine component (tetracarboxylic anhydride component/diamine component) is preferably 0.97 to 1.1, and by setting such a molar ratio, the molecular weight of the polyimide can be controlled more easily.

The dimer diamine composition may be a commercially available product, and is preferably purified for the purpose of reducing components other than the dimer diamine as the component (a), and is preferably, for example, 96% by weight or more of the component (a). The purification method is not particularly limited, but conventional methods such as distillation and precipitation purification are suitable. Examples of commercially available dimer diamine compositions include: priiramine (praiamine) 1073 (trade name) manufactured by Croda japonica (Croda Japan), priiramine (praiamine) 1074 (trade name) manufactured by Croda japonica (Croda Japan), priiramine (praiamine) 1075 (trade name) manufactured by Croda japonica (Croda Japan), and the like.

As described under condition b2, the adhesive polyimide may contain a diamine residue derived from a diamine compound represented by the general formula (a 1). In the diamine represented by the general formula (a1), since aromatic rings are bonded to each other at a para position with respect to amino groups, molecular chains are easily oriented, and thus, the diamine can be advantageously used for the purpose of reducing the dielectric loss tangent.

[ solution 7]

In the formula (A1), Y and Z independently represent a C1-6 monovalent alkyl group, alkoxy group, alkenyl group or alkynyl group, and the linking group X represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-CH₂-O-、-C(CH₃)₂A divalent group in- (O-X-O) -, - (Y-H) -, - (Y-O) -, or- (Y-O) -CONH) -, and m independently represents an integer of 1 to 4. When a plurality of linking groups X are contained in the molecule, they may be the same or different. Furthermore, in the formula (A1), the hydrogen atoms in the terminal two amino groups may be substituted, and may be, for example, -NR₂R₃(Here, R is₂、R₃Independently, an optional substituent such as an alkyl group).

Diamine represented by the formula (A1) [ hereinafter, sometimes referred to as "diamine (A1 ]"]Is an aromatic diamine having two or more benzene rings. The diamine (a1) is believed to contribute to the improvement of the orientation of the polyimide molecular chain by having the amino group directly bonded to at least one benzene ring and the divalent linking group X in the para-position. Therefore, the use of the diamine (a1) improves the low dielectric characteristics of the polyimide. Here, the linking group X is preferably-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-CH₂-O-、-C(CH₃)₂-、-NH-、-CONH-。

Examples of the diamine (a1) include: 2,2-bis [4- (4-aminophenoxy) phenyl ] propane, 2,4,4' -triaminodiphenyl ether, 4,4' -bis (4-aminophenyl sulfide), 4,4' -diaminodiphenyl sulfone, 2' -bis (4-aminobenzyloxyphenyl) propane, bis [4- (4-aminophenoxy) phenyl ] sulfone, 4,4' -diaminobenzanilide, 4,4' -methylenedianiline, 4,4' -diaminobenzophenone, and the like. Of these, 2-bis [4- (4-aminophenoxy) phenyl ] propane is particularly preferable.

The adhesive polyimide preferably contains a diamine residue derived from at least one diamine compound selected from the group consisting of diamines (a1) in an amount of 5 to 40 mol%, preferably 10 to 30 mol%, based on the total diamine residues. Since the diamine (a1) has a structure with high linearity, the use of at least one diamine compound selected from the diamines (a1) in an amount within the above range can improve the orientation of the polyimide molecular chain and impart low dielectric characteristics. When the diamine residue derived from at least one diamine compound selected from the group consisting of diamines (a1) exceeds 40 mol%, the polarity of the polyimide molecule becomes high and the dielectric loss tangent increases. In addition, the solubility of polyimide decreases, which causes gelation. On the other hand, if the amount is less than 5 mol%, the movement of the molecular chains cannot be suppressed, and the dielectric loss tangent increases.

The adhesive polyimide may contain diamine residues as listed below when the conditions a, b1, and c are satisfied. As such a diamine residue, for example, a diamine residue derived from bisaniline fluorene (BAFL), 9-bis (3-methyl-4-aminophenyl) fluorene, 9-bis (3-fluoro-4-aminophenyl) fluorene, 9-bis [4- (aminophenoxy) phenyl ] fluorene, or a diamine compound represented by general formula (B1) to general formula (B7) is preferable. Particularly, the diamine having a fluorene skeleton represented by BAFL contains four aromatic rings, and thus can be advantageously used for the purpose of adjusting the aromatic ring concentration.

[ solution 8]

In the formulae (B1) to (B7), R₁Independently represents a C1-6 monovalent hydrocarbon group or an alkoxy group, and the linking group A independently represents a group selected from-O-, -S-, -CO-, -SO-, -SO₂-、-COO-、-CH₂-、-C(CH₃)₂A divalent radical of-NH-or-CONH-, n₁Independently represent an integer of 0 to 4. Wherein a portion that overlaps with formula (B2) is removed from formula (B3), and a portion that overlaps with formula (B4) is removed from formula (B5). Here, "independently" means that a plurality of linking groups A and a plurality of R are present in one or two or more of the formulae (B1) to (B7)₁Or a plurality of n₁May be the same or different. Further, in the formulae (B1) to (B7), the hydrogen atoms in the terminal two amino groups may be substituted, and for example, may be-NR₂R₃(Here, R is₂、R₃Independently, an optional substituent such as an alkyl group).

The diamine represented by the formula (B1) (hereinafter, sometimes referred to as "diamine (B1)") is an aromatic diamine having two benzene rings. The diamine (B1) is considered to have an increased degree of freedom and high flexibility in the polyimide molecular chain due to the meta position between the amino group directly bonded to at least one benzene ring and the divalent linking group a, and to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, by using the diamine (B1), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-, -CH₂-、-C(CH₃)₂-、-CO-、-SO₂-、-S-。

Examples of the diamine (B1) include: 3,3 '-diaminodiphenylmethane, 3' -diaminodiphenylpropane, 3 '-diaminodiphenylsulfide, 3' -diaminodiphenylsulfone, 3 '-diaminodiphenylether, 3,4' -diaminodiphenylmethane, 3,4 '-diaminodiphenylpropane, 3,4' -diaminodiphenylsulfide, 3 '-diaminobenzophenone, (3,3' -diamino) diphenylamine and the like.

The diamine represented by the formula (B2) (hereinafter, sometimes referred to as "diamine (B2)") is an aromatic diamine having three benzene rings. The diamine (B2) is considered to have an increased degree of freedom and high flexibility in the polyimide molecular chain due to the meta position between the amino group directly bonded to at least one benzene ring and the divalent linking group a, and to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, by using the diamine (B2), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-.

Examples of the diamine (B2) include: 1, 4-bis (3-aminophenoxy) benzene, 3- [4- (4-aminophenoxy) phenoxy ] aniline, 3- [3- (4-aminophenoxy) phenoxy ] aniline, and the like.

The diamine represented by the formula (B3) (hereinafter, sometimes referred to as "diamine (B3)") is an aromatic diamine having three benzene rings. The diamine (B3) is believed to have an increased degree of freedom and high flexibility in the polyimide molecular chain due to the fact that the two divalent linking groups a directly bonded to one benzene ring are in a meta position with respect to each other, and thus contributes to the improvement of flexibility of the polyimide molecular chain. Therefore, by using the diamine (B3), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-.

Examples of the diamine (B3) include: 1,3-bis (4-aminophenoxy) benzene (1,3-bis (4-aminophenoxy) bezene, TPE-R), 1,3-bis (3-aminophenoxy) benzene (1,3-bis (3-aminophenoxy) bezene, APB), 4' - [ 2-methyl- (1, 3-phenylene) dioxy ] dianiline, 4' - [ 4-methyl- (1, 3-phenylene) dioxy ] dianiline, 4' - [ 5-methyl- (1, 3-phenylene) dioxy ] dianiline, and the like.

The diamine represented by the formula (B4) (hereinafter, sometimes referred to as "diamine (B4)") is an aromatic diamine having four benzene rings. The diamine (B4) is considered to have high flexibility by the amino group directly bonded to at least one benzene ring being in the meta position to the divalent linking group a, and to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, by using the diamine (B4), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-, -CH₂-、-C(CH₃)₂-、-SO₂-、-CO-、-CONH-。

Examples of the diamine (B4) include: bis [4- (3-aminophenoxy) phenyl ] methane, bis [4- (3-aminophenoxy) phenyl ] propane, bis [4- (3-aminophenoxy) phenyl ] ether, bis [4- (3-aminophenoxy) phenyl ] sulfone, bis [4- (3-aminophenoxy) ] benzophenone, bis [4,4' - (3-aminophenoxy) ] benzanilide, and the like.

The diamine represented by the formula (B5) (hereinafter, sometimes referred to as "diamine (B5)") is an aromatic diamine having four benzene rings. The diamine (B5) is believed to have an increased degree of freedom and high flexibility in the polyimide molecular chain due to the fact that the two divalent linking groups a directly bonded to at least one benzene ring are in a meta position with respect to each other, and thus contributes to the improvement of flexibility of the polyimide molecular chain. Therefore, by using the diamine (B5), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-.

Examples of the diamine (B5) include 4- [3- [4- (4-aminophenoxy) phenoxy ] aniline and 4,4' - [ oxybis (3, 1-phenylene) ] dianiline.

The diamine represented by the formula (B6) (hereinafter, sometimes referred to as "diamine (B6)") is an aromatic diamine having four benzene rings. The diamine (B6) is considered to have high flexibility by having at least two ether bonds, and to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, by using the diamine (B6), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-C (CH)₃)₂-、-O-、-SO₂-、-CO-。

Examples of the diamine (B6) include: 2,2-bis [4- (4-aminophenoxy) phenyl ] propane (2,2-bis [4- (4-aminophenoxy) phenyl ] propane, BAPP), bis [4- (4-aminophenoxy) phenyl ] ether (bis [4- (4-aminophenoxy) phenyl ] ether, BAPE), bis [4- (4-aminophenoxy) phenyl ] sulfone (bis [4- (4-aminophenoxy) phenyl ] sulfone, BAPS), bis [4- (4-aminophenoxy) phenyl ] ketone (bis [4- (4-aminophenoxy) phenyl ] ketone, BAPK), and the like.

The diamine represented by the formula (B7) (hereinafter, sometimes referred to as "diamine (B7)") is an aromatic diamine having four benzene rings. The diamine (B7) has a divalent linking group a having high flexibility on each side of the diphenyl skeleton, and therefore is considered to contribute to improvement in flexibility of the polyimide molecular chain. Therefore, by using the diamine (B7), the thermoplasticity of the polyimide is improved. Here, the linking group A is preferably-O-.

Examples of the diamine (B7) include bis [4- (3-aminophenoxy) ] biphenyl and bis [4- (4-aminophenoxy) ] biphenyl.

The adhesive polyimide preferably contains a diamine residue derived from at least one diamine compound selected from the group consisting of diamines (B1) to diamines (B7) in an amount of preferably 1 to 40 mol%, more preferably 5 to 35 mol%, based on the total diamine residues. Since the diamines (B1) to (B7) have a molecular structure having flexibility, the flexibility of the polyimide molecular chain can be improved and thermoplasticity can be imparted by using at least one diamine compound selected from these in an amount within the above range.

The adhesive polyimide may further contain a diamine residue other than the above-described diamine residue within a range not impairing the effects of the present invention.

The adhesive polyimide can be produced by: the acid anhydride component and the diamine component are reacted in a solvent to produce a polyamic acid, and then the polyamic acid is heated to be closed. For example, a polyamic acid as a precursor of a polyimide can be obtained by dissolving an acid anhydride component and a diamine component in an organic solvent in approximately equimolar amounts, and stirring the solution at a temperature in the range of 0 to 100 ℃ for 30 minutes to 24 hours to perform a polymerization reaction. During the reaction, the reaction components are dissolved so that the produced precursor is in the range of 5 to 50 wt%, preferably 10 to 40 wt% in the organic solvent. Examples of the organic solvent used in the polymerization reaction include: n, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, Dimethylsulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), methanol, ethanol, benzyl alcohol, cresol, and the like. Two or more of these solvents may be used in combination, and an aromatic hydrocarbon such as xylene or toluene may be used in combination. The amount of the organic solvent used is not particularly limited, but is preferably adjusted so that the concentration of the polyamic acid solution obtained by the polymerization reaction is about 5 to 50 wt%.

The polyamic acid synthesized is advantageously used as a reaction solvent solution, and may be concentrated, diluted or replaced with another organic solvent as necessary. In addition, polyamic acid is generally excellent in solvent solubility and is therefore advantageously used. The viscosity of the solution of the polyamic acid is preferably in the range of 500 mPas to 100000 mPas. If the amount is outside the above range, defects such as uneven thickness and streaks are likely to occur in the film during coating work using a coater or the like.

The method for imidizing the polyamic acid to form the polyimide is not particularly limited, and for example, heat treatment such as heating at a temperature in the range of 80 to 400 ℃ for 1 to 24 hours in the solvent can be suitably employed. The temperature may be changed during the heating process, or may be changed under a constant temperature condition.

By selecting the types of the acid anhydride component and the diamine component or by selecting the molar ratio of two or more types of the acid anhydride component and the diamine component in the adhesive polyimide, physical properties such as dielectric properties, thermal expansion coefficient, tensile elastic modulus, and glass transition temperature can be controlled. When the adhesive polyimide has a plurality of structural units, the structural units may be present in the form of blocks or may be present randomly, but preferably are present randomly.

The imide group concentration of the adhesive polyimide is preferably 22 wt% or less, and more preferably 20 wt% or less. Here, the "imide group concentration" refers to the imide group (- (CO) in the polyimide₂A value obtained by dividing the molecular weight of-N-) by the molecular weight of the entire structure of the polyimide. When the imide group concentration exceeds 22% by weight, the molecular weight of the resin itself becomes small, and low hygroscopicity is also deteriorated due to the increase of polar groups, and Tg and elastic modulus are increased。

The adhesive polyimide is most preferably a completely imidized structure. However, a part of the polyimide may be amic acid. The imidization ratio can be measured by measuring the infrared absorption spectrum of the polyimide film by using a Fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by Japanese Spectroscopy) and by the Attenuated Total Reflection (ATR) method at 1015cm^-1Based on the near benzene ring absorber, according to 1780cm^-1The absorbance of C ═ O stretching derived from the imide group (b) was calculated.

The adhesive polyimide can be prepared as an adhesive polyimide composition by appropriately mixing other hardening resin components such as plasticizers and epoxy resins, a curing agent, a curing accelerator, an organic filler, an inorganic filler, a coupling agent, a solvent, a flame retardant, and the like as optional components.

(crosslinking formation of adhesive polyimide)

When the adhesive polyimide has a ketone group, the ketone group and an amino group of an amino compound having at least two primary amino groups as functional groups (hereinafter, sometimes referred to as "crosslinking amino compound") are reacted with each other to form a C ═ N bond, whereby a crosslinked structure can be formed. Such a polyimide having a crosslinked structure (hereinafter, sometimes referred to as "crosslinked polyimide") is an example of an application of the adhesive polyimide, and is a preferred embodiment. Since the weight average molecular weight greatly varies due to the crosslinking formation, the condition c may be satisfied with the adhesive polyimide before the crosslinking formation, and the condition c may not be satisfied with the crosslinked polyimide. An adhesive resin composition obtained by blending a crosslinking agent with an adhesive polyimide having a ketone group is another application example of the adhesive polyimide, and is a preferred embodiment. The heat resistance of the adhesive polyimide can be improved by forming a crosslinked structure. Examples of the tetracarboxylic anhydride preferable for forming the adhesive polyimide having a ketone group include 3,3',4,4' -benzophenonetetracarboxylic dianhydride (BTDA), and examples of the diamine compound include aromatic diamines such as 4,4'-bis (3-aminophenoxy) benzophenone (4,4' -bis (3-aminophenoxy) benzophenone, BABP), and 1,3-bis [4- (3-aminophenoxy) benzoyl ] benzene (1,3-bis [4- (3-aminophenoxy) benzoyl ] benzene, BABB).

In particular, for the purpose of forming a crosslinked structure, it is preferable that the crosslinking-forming amino compound is allowed to act on the adhesive polyimide containing preferably 50 mol% or more, more preferably 60 mol% or more of BTDA residues derived from BTDA with respect to all tetracarboxylic acid residues. In the present invention, the term "BTDA residue" refers to a tetravalent group derived from BTDA.

Examples of the amino compound for forming a crosslink include: (I) dihydrazide compounds, (II) aromatic diamines, (III) aliphatic amines, and the like. Among these, dihydrazide compounds are preferred. Aliphatic amines other than dihydrazide compounds tend to form a crosslinked structure even at room temperature, and thus the storage stability of varnish may be concerned. As described above, when the dihydrazide compound is used, both the storage stability of the varnish and the curing time can be reduced. The dihydrazide compounds include, for example, dihydrazide compounds such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide, dodecane acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, diethylene glycol dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2, 6-naphthalene carboxylic acid dihydrazide, 4-bis-benzene dihydrazide, 1, 4-naphthalene carboxylic acid dihydrazide, 2, 6-pyridine dicarboxylic acid dihydrazide, and itaconic acid dihydrazide. The dihydrazide compounds may be used alone or in combination of two or more.

The amino compound such as the dihydrazide compound (I), the aromatic diamine (II), and the aliphatic amine (III) may be used in combination of two or more kinds, for example, in a super-range such as a combination of (I) and (II), a combination of (I) and (III), and a combination of (I) and (II) and (III).

In addition, from the viewpoint of making the network structure formed by crosslinking with the crosslinking-forming amino compound denser, the molecular weight (weight average molecular weight in the case where the crosslinking-forming amino compound is an oligomer) of the crosslinking-forming amino compound used in the present invention is preferably 5,000 or less, more preferably 90 to 2,000, and even more preferably 100 to 1,500. Among them, particularly preferred is an amino compound for forming a crosslink, which has a molecular weight of 100 to 1,000. When the molecular weight of the amino compound for forming crosslinks is less than 90, one amino group of the amino compound for forming crosslinks forms a C ═ N bond with the ketone group of the adhesive polyimide, and the volume around the remaining amino group increases three-dimensionally, so that the remaining amino group tends to be less likely to form a C ═ N bond.

In the case where the ketone group in the adhesive polyimide and the amino compound for crosslinking are crosslinked, the amino compound for crosslinking is added to a resin solution containing the adhesive polyimide, and the ketone group in the adhesive polyimide and the primary amino group of the amino compound for crosslinking are subjected to a condensation reaction. The condensation reaction hardens the resin solution to form a hardened material. In this case, the amount of the amino compound for forming crosslinks may be 0.004 to 1.5 moles, preferably 0.005 to 1.2 moles, more preferably 0.03 to 0.9 moles, and most preferably 0.04 to 0.6 moles, in total, of the primary amino groups with respect to 1 mole of the ketone groups. If the amount of the amino compound for forming a crosslink is less than 0.004 mole in total based on 1 mole of the ketone group, the crosslinking by the amino compound for forming a crosslink tends to be insufficient, and thus the heat resistance after curing tends to be hard to develop, whereas if the amount of the amino compound for forming a crosslink exceeds 1.5 mole, the unreacted amino compound for forming a crosslink acts as a thermoplastic agent, and the heat resistance of the adhesive layer tends to be lowered.

The conditions for the condensation reaction by crosslinking are not particularly limited as long as the ketone group in the adhesive polyimide reacts with the primary amino group of the amino compound for crosslinking to form an imine bond (C ═ N bond). Closing deviceThe temperature for the heat condensation is preferably in the range of 120 to 220 ℃, and more preferably in the range of 140 to 200 ℃ for the reasons of discharging water produced by condensation to the outside of the system, or simplifying the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the adhesive polyimide. The reaction time is preferably about 30 minutes to 24 hours. The end point of the reaction can be determined by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercially available product: FT/IR620 manufactured by Nippon spectral Co., Ltd.) and using 1670cm^-1Decrease or disappearance of absorption peak derived from ketone group in polyimide resin in the vicinity thereof, and 1635cm^-1The appearance of nearby absorption peaks originating from imine groups.

The thermal condensation of the ketone group of the adhesive polyimide and the primary amino group of the amino compound for crosslinking formation can be carried out, for example, by the following method:

(1) a method in which an amino compound for crosslinking formation is added immediately after the synthesis (imidization) of an adhesive polyimide and the resultant mixture is heated;

(2) a method in which an excess amount of an amino compound is previously charged as a diamine component, and the remaining amino compound not involved in imidization or amidation is used as an amino compound for crosslinking formation and heated together with the adhesive polyimide immediately after the synthesis of the adhesive polyimide (imidization);

or

(3) A method of heating after processing the composition of the adhesive polyimide to which the amino compound for crosslinking formation is added into a predetermined shape (for example, after applying the composition to an arbitrary substrate or after forming the composition into a film).

In order to impart heat resistance to the adhesive polyimide, an example of a crosslinked polyimide having a crosslinked structure formed by forming a imide bond is described, but the present invention is not limited thereto, and as a method for curing the polyimide, for example, a compound having an unsaturated bond such as an epoxy resin, an epoxy resin curing agent, maleimide, an activated ester resin, or a resin having a styrene skeleton may be blended and cured.

[ adhesive resin composition ]

Since the adhesive polyimide is soluble in a solvent, it can be used in the form of a composition containing a solvent. That is, the adhesive resin composition contains an adhesive polyimide and a solvent capable of dissolving the adhesive polyimide. The adhesive resin composition may contain an amino compound for forming a crosslink as an optional component. The adhesive resin composition contains an adhesive polyimide as a main component of a resin component, preferably 70% by weight or more of the resin component, more preferably 90% by weight or more of the resin component, and most preferably the entire resin component. The main component of the resin component is a component contained in an amount of more than 50% by weight based on the total resin component.

The solvent is not particularly limited as long as it is a solvent that can dissolve the adhesive polyimide, and examples thereof include: n, N-Dimethylformamide (DMF), N-dimethylacetamide (DMAc), N-diethylacetamide, N-methyl-2-pyrrolidone (NMP), 2-butanone, dimethyl sulfoxide (DMSO), hexamethylphosphoramide, N-methylcaprolactam, dimethyl sulfate, cyclohexanone, methylcyclohexane, dioxane, tetrahydrofuran, diglyme (diglyme), triglyme (triglyme), methanol, ethanol, benzyl alcohol, cresol, acetone, and the like. Two or more of these solvents may be used in combination, and an aromatic hydrocarbon such as xylene or toluene may be used in combination.

The blending ratio of the adhesive polyimide and the solvent in the adhesive resin composition is not particularly limited as long as the viscosity of the adhesive resin composition can be maintained to such an extent that the composition can be applied. The viscosity of the adhesive resin composition is preferably in the range of, for example, 500 to 100000 mPas. If the amount is outside the above range, defects such as thickness unevenness and streaks are likely to occur in the resin film during the coating operation.

The adhesive resin composition may contain, as optional components, other hardening resin components such as plasticizers and epoxy resins, a hardening agent, a hardening accelerator, an organic filler, an inorganic filler, a coupling agent, and a flame retardant, as long as the effects of the invention are not impaired.

[ adhesive film ]

The adhesive film according to an embodiment of the present invention is a film obtained by processing the adhesive polyimide or the crosslinked polyimide into a film form. The adhesive film is not particularly limited as long as it contains the adhesive polyimide or crosslinked polyimide as a main component of the resin component, preferably 70% by weight or more of the resin component, more preferably 90% by weight or more of the resin component, and most preferably all of the resin component. The main component of the resin component is a component contained in an amount of more than 50% by weight based on the total resin component. The adhesive film may be a film (sheet) containing an adhesive polyimide or a crosslinked polyimide, and may be, for example, a film laminated on a base material of an inorganic material such as a copper foil or a glass plate or a resin base material such as a polyimide film, a polyamide film, or a polyester film. The adhesive film may be suitably formulated with, for example, other hardening resin components such as plasticizers and epoxy resins, a hardening agent, a hardening accelerator, an organic filler, an inorganic filler, a coupling agent, a flame retardant, and the like as optional components.

The adhesive film made of the adhesive polyimide satisfying the conditions a, b1, and c is preferably a dielectric loss tangent (Tan δ) at 10GHz measured by separating the dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₁) Has a relative dielectric constant (E) of 0.005 or less₁) Is 3.0 or less. Dielectric loss tangent (Tan. delta.)₁) And relative dielectric constant (E)₁) If the amount exceeds the above value, the dielectric loss is increased when the dielectric ceramic is applied to a circuit board, and a problem such as loss of an electric signal is likely to occur in a transmission path of a high-frequency signal.

The adhesive film made of the adhesive polyimide satisfying the conditions a, b1, and c is preferably a dielectric loss tangent (Tan δ) at 20GHz measured by separating the dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₂) Has a relative dielectric constant (E) of 0.005 or less₂) Is 3.0 or less. Dielectric loss tangent (Tan. delta.)₂) And relative dielectric constant (E)₂) If the value exceeds the above range, the composition is applied to a circuit boardThis leads to an increase in dielectric loss, and tends to cause problems such as loss of electric signals in a transmission path of high-frequency signals.

Further, the adhesive film formed of the adhesive polyimide satisfying the conditions a, b1, and c is preferably a dielectric loss tangent (Tan δ) at 10GHz measured by separating the dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₁) Dielectric loss tangent (Tan. delta.) at 20GHz₂) Difference of (Tan delta)₂-Tanδ₁) Is 0 or less. Difference (Tan. delta.)₂-Tanδ₁) The case of 0 or less means that even if the frequency is increased from 10GHz to 20GHz, the transmission loss does not increase but is the same or decreases.

On the other hand, the adhesive film formed of the adhesive polyimide satisfying the conditions a, b2, and c is preferably a dielectric loss tangent (Tan δ) at 10GHz measured by separating the dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₁) Less than 0.002, relative dielectric constant (E)₁) Is 3.0 or less. Dielectric loss tangent (Tan. delta.)₁) And relative dielectric constant (E)₁) If the amount exceeds the above value, the dielectric loss is increased when the dielectric ceramic is applied to a circuit board, and a problem such as loss of an electric signal is likely to occur in a transmission path of a high-frequency signal.

The adhesive film made of the adhesive polyimide satisfying the conditions a, b2, and c is preferably a dielectric loss tangent (Tan δ) at 20GHz measured by separating the dielectric resonator (SPDR) after humidity conditioning for 24 hours under constant temperature and humidity conditions (normal state) of 23 ℃ and 50% RH₂) Less than 0.002, relative dielectric constant (E)₂) Is 3.0 or less. Dielectric loss tangent (Tan. delta.)₂) And relative dielectric constant (E)₂) If the amount exceeds the above value, the dielectric loss is increased when the dielectric ceramic is applied to a circuit board, and a problem such as loss of an electric signal is likely to occur in a transmission path of a high-frequency signal.

The tensile elastic modulus of the adhesive film is preferably 3000MPa or less, preferably 100MPa or more and 2500MPa or less, and more preferably 200MPa or more and 2000MPa or less. When the tensile elastic modulus is less than 100MPa, the film is likely to have wrinkles, and handling properties such as occurrence of air inclusion during lamination are deteriorated. When the tensile elastic modulus exceeds 3000MPa, warpage occurs and dimensional stability is lowered when the substrate and the adhesive film are laminated. By setting the tensile elastic modulus, a laminate having excellent handleability, suppressed warpage, and excellent dimensional stability can be obtained.

The method for producing the adhesive film of the present embodiment is not particularly limited, but the following methods [1] to [3] can be exemplified.

[1] A method in which an adhesive polyimide is applied to an arbitrary substrate in a solution state (for example, in the state of an adhesive resin composition) to form a coating film, and the coating film is dried and formed into a film at a temperature of, for example, 80 to 180 ℃, and then peeled from the substrate as necessary.

[2] A method in which a solution of polyamic acid as a precursor of an adhesive polyimide is applied to an arbitrary substrate, dried, imidized, formed into a film, and then peeled off from the substrate as necessary.

[3] A method of coating a solution of polyamic acid as a precursor of an adhesive polyimide on an arbitrary substrate, drying the solution, and then peeling the gel film of polyamic acid from the substrate to perform imidization to obtain an adhesive film.

The method for applying the solution of the adhesive polyimide (or the polyamic acid solution) to the substrate is not particularly limited, and the solution can be applied by a coater such as a die wheel, a die, a knife, or a die lip.

Next, specific examples of the laminate, the metal-clad laminate, the circuit board, and the multilayer circuit board, which are preferred embodiments to which the adhesive film is applied, will be described.

[ laminate ]

For example, as shown in fig. 1, a laminate 100 according to an embodiment of the present invention includes a base 10 and an adhesive layer 20 laminated on at least one surface of the base 10, and the adhesive layer 20 includes the adhesive film. The laminate 100 may include any layer other than the above layers. Examples of the substrate 10 in the laminate 100 include: inorganic substrates such as copper foil and glass plate, and resin substrates such as polyimide film, polyamide film and polyester film. The laminate 100 can be produced according to any one of [1] to [3] of the above-described adhesive film production methods, except that it is not peeled from the substrate 10. Alternatively, the laminate 100 may be produced by preparing and bonding the substrate 10 and the adhesive film separately.

Preferred embodiments of the laminate 100 include a coverlay film and a resin-coated copper foil.

(cover film)

The cover film as one embodiment of the laminate 100 includes a covering film layer as the base 10 and an adhesive layer 20 laminated on one surface of the covering film layer, although not shown, and the adhesive layer 20 includes the adhesive film. The cover film may include any other layer than the above layers.

The material of the covering film layer is not particularly limited, and for example, a polyimide film such as a polyimide resin, a polyetherimide resin, or a polyamideimide resin, a polyamide film, a polyester film, or the like can be used. Among these, polyimide-based films having excellent heat resistance are preferably used. In addition, in order to effectively exhibit light-shielding properties, concealing properties, design properties, and the like, the covering film material layer may contain a black pigment, and may contain an optional component such as a matte pigment for suppressing surface gloss within a range not impairing the effect of improving the dielectric characteristics.

The thickness of the covering film layer is not particularly limited, and is preferably in the range of, for example, 5 μm to 100 μm.

The thickness of the adhesive layer 20 is not particularly limited, and is preferably in the range of 10 μm to 75 μm, for example.

The cover film of the present embodiment can be produced by the following method.

First, as a first method, a cover film having a covering film layer and an adhesive layer 20 can be formed by applying a polyimide to be the adhesive layer 20 in a solution state (for example, preferably in a varnish state containing a solvent, preferably an adhesive resin composition) to one surface of the covering film layer, and then drying the coating at a temperature of, for example, 80 to 180 ℃.

As a second method, a polyimide for the adhesive layer 20 is applied in a solution state (for example, preferably in a varnish state containing a solvent, preferably an adhesive resin composition) to an arbitrary substrate, dried at a temperature of, for example, 80 to 180 ℃, and then peeled off to form an adhesive film for the adhesive layer 20, and the adhesive film and the covering film material layer are thermally pressed at a temperature of, for example, 60 to 220 ℃ to form a cover film.

(copper foil with resin)

Although not shown, a resin-coated copper foil as another embodiment of the laminate 100 is formed by laminating an adhesive layer 20 on at least one side of a copper foil as a base material 10, and the adhesive layer 20 includes the adhesive film. The resin-coated copper foil of the present embodiment may include any layer other than the above layers.

The thickness of the adhesive layer 20 in the resin-coated copper foil is, for example, preferably in the range of 0.1 to 125 μm, and more preferably in the range of 0.3 to 100 μm. If the thickness of the adhesive layer 20 is less than the lower limit, a problem may occur in that sufficient adhesiveness cannot be ensured. On the other hand, if the thickness of the adhesive layer 20 exceeds the above upper limit, a problem such as a decrease in dimensional stability occurs. In addition, from the viewpoint of reducing the dielectric constant and the dielectric loss tangent, the thickness of the adhesive layer 20 is preferably 3 μm or more.

The material of the copper foil in the resin-coated copper foil is preferably copper or a copper alloy as a main component. The thickness of the copper foil is preferably 35 μm or less, and more preferably in the range of 5 to 25 μm. From the viewpoint of production stability and handling property, the lower limit of the thickness of the copper foil is preferably set to 5 μm. The copper foil may be a rolled copper foil or an electrolytic copper foil. As the copper foil, a commercially available copper foil can be used.

The resin-attached copper foil can be prepared, for example, by forming a seed layer by sputtering a metal on an adhesive film and then forming a copper layer by, for example, copper plating, or by laminating an adhesive film and a copper foil by a method such as thermocompression bonding. Further, in order to form the adhesive layer 20 on the copper foil, the resin-coated copper foil may be prepared by casting a coating solution of an adhesive polyimide or a precursor thereof, drying the casting solution to form a coating film, and then performing a desired heat treatment.

[ Metal-clad laminate ]

(first embodiment)

The metal-clad laminate according to one embodiment of the present invention includes an insulating resin layer, and a metal layer laminated on at least one surface of the insulating resin layer, and at least one layer of the insulating resin layer includes the adhesive film. The metal-clad laminate of the present embodiment may include any layer other than the above layers.

(second embodiment)

For example, as shown in fig. 2, a metal-clad laminate according to another embodiment of the present invention is a so-called three-layer metal-clad laminate 101 including an insulating resin layer 30, an adhesive layer 20 laminated on at least one surface of the insulating resin layer 30, and a metal layer M laminated on the insulating resin layer 30 via the adhesive layer 20, wherein the adhesive layer 20 includes the adhesive film. The three-layer metal-clad laminate 101 may include any layer other than the above layers. In the three-layer metal-clad laminate 101, the adhesive layer 20 may be provided on one surface or both surfaces of the insulating resin layer 30, and the metal layer M may be provided on one surface or both surfaces of the insulating resin layer 30 through the adhesive layer 20. That is, the three-layer metal-clad laminate 101 may be a single-side metal-clad laminate or a double-side metal-clad laminate. The metal layer M of the three-layer metal-clad laminate 101 is etched and subjected to wiring circuit processing to manufacture a single-sided FPC or a double-sided FPC.

The insulating resin layer 30 in the three-layer metal-clad laminate 101 is not particularly limited as long as it contains a resin having electrical insulation properties, and examples thereof include polyimide, epoxy resin, phenol resin, polyethylene, polypropylene, polytetrafluoroethylene, silicone, Ethylene Tetrafluoroethylene (ETFE), and the like, and preferably polyimide. The polyimide layer constituting the insulating resin layer 30 may be a single layer or a plurality of layers, but preferably includes a non-thermoplastic polyimide layer.

The thickness of the insulating resin layer 30 in the three-layer metal-clad laminate 101 is, for example, preferably in the range of 1 μm to 125 μm, and more preferably in the range of 5 μm to 100 μm. If the thickness of the insulating resin layer 30 is less than the lower limit value, a problem may occur in that sufficient electrical insulation cannot be ensured. On the other hand, if the thickness of the insulating resin layer 30 exceeds the above upper limit, a defect such as warpage of the metal-clad laminate is likely to occur.

The thickness of adhesive layer 20 in three-layer metal-clad laminate 101 is preferably in the range of 0.1 to 125 μm, and more preferably in the range of 0.3 to 100 μm, for example. In the three-layer metal-clad laminate 101 of the present embodiment, if the thickness of the adhesive layer 20 is less than the lower limit, a problem may occur in that sufficient adhesiveness cannot be ensured. On the other hand, if the thickness of the adhesive layer 20 exceeds the above upper limit, a problem such as a decrease in dimensional stability occurs. In addition, from the viewpoint of reducing the dielectric constant and the dielectric loss tangent of the entire insulating layer as a laminate of the insulating resin layer 30 and the adhesive layer 20, the thickness of the adhesive layer 20 is preferably 3 μm or more.

The ratio of the thickness of the insulating resin layer 30 to the thickness of the adhesive layer 20 (thickness of the insulating resin layer 30/thickness of the adhesive layer 20) is, for example, preferably in the range of 0.1 to 3.0, and more preferably in the range of 0.15 to 2.0. By setting such a ratio, warpage of the three-layer metal-clad laminate 101 can be suppressed. In addition, the insulating resin layer 30 may contain a filler, if necessary. Examples of the filler include: silicon dioxide, aluminum oxide, magnesium oxide, beryllium oxide, boron nitride, aluminum nitride, silicon nitride, aluminum fluoride, calcium fluoride, metal salts of organic phosphinic acids, and the like. These may be used singly or in combination of two or more.

(third embodiment)

For example, as shown in fig. 3, a metal-clad laminate according to still another embodiment of the present invention is a bonded metal-clad laminate 102 in which at least two single-sided metal-clad laminates are bonded to each other with an adhesive layer 20 interposed therebetween. The bonded metal clad laminate 102 includes: a first single-sided metal-clad laminate 41; a second single-sided metal-clad laminate 42; and an adhesive layer 20 laminated between the first single-sided metal-clad laminate 41 and the second single-sided metal-clad laminate 42, the adhesive layer 20 including the adhesive film.

Here, the first single-sided metal-clad laminate 41 includes the first metal layer M1 and the first insulating resin layer 31 laminated on at least one side of the first metal layer M1. The second single-sided metal-clad laminate 42 includes a second metal layer M2 and a second insulating resin layer 32 laminated on at least one side of the second metal layer M2. The adhesive layer 20 is disposed so as to be in contact with the first insulating resin layer 31 and the second insulating resin layer 32. The laminated metal-clad laminate 102 may include any layer other than the above layers.

The first insulating resin layer 31 and the second insulating resin layer 32 in the conformable metal-clad laminate 102 may have the same structure as the insulating resin layer 30 of the second form of the three-layer metal-clad laminate 101.

The bonded metal clad laminate 102 may be manufactured by: a first single-sided metal-clad laminate 41 and a second single-sided metal-clad laminate 42 are prepared, and an adhesive film is disposed between the first insulating resin layer 31 and the second insulating resin layer 32 and bonded thereto.

(fourth embodiment)

For example, as shown in fig. 4, a metal-clad laminate according to still another embodiment of the present invention is an adhesive layer-equipped metal-clad laminate 103 including a single-sided metal-clad laminate having an insulating resin layer 33 and a metal layer M laminated on one surface of the insulating resin layer 33, and an adhesive layer 20 laminated on the other surface of the insulating resin layer 33, wherein the adhesive layer 20 includes the adhesive film. The metal-clad laminate 103 with an adhesive layer may include any layer other than the above.

The insulating resin layer 33 in the metal-clad laminate 103 with an adhesive layer may be the same structure as the insulating resin layer 30 of the three-layer metal-clad laminate 101 in the second form.

The metal-clad laminate 103 with an adhesive layer can be manufactured as follows: a single-sided metal-clad laminate having an insulating resin layer 33 and a metal layer M is prepared, and an adhesive film is bonded to the insulating resin layer 33 side.

In any of the exemplary first to fourth embodiments, the material of the metal layer M (including the first metal layer M1 and the second metal layer M2; the same applies hereinafter) is not particularly limited, and examples thereof include: copper, stainless steel, iron, nickel, beryllium, aluminum, zinc, indium, silver, gold, tin, zirconium, tantalum, titanium, lead, magnesium, manganese, alloys thereof, and the like. Among them, copper or a copper alloy is particularly preferable. The material of the wiring layer in the circuit board to be described later is also the same as that of the metal layer M1.

The thickness of the metal layer M is not particularly limited, but when a metal foil such as copper foil is used, it is preferably 35 μ M or less, and more preferably in the range of 5 to 25 μ M. From the viewpoint of production stability and handling property, the lower limit of the thickness of the metal foil is preferably set to 5 μm. When a copper foil is used, the copper foil may be a rolled copper foil or an electrolytic copper foil. As the copper foil, a commercially available copper foil can be used. For example, the metal foil may be subjected to surface treatment with a wall board (fixing), an aluminum alcoholate, an aluminum chelate compound, a silane coupling agent, or the like for the purpose of, for example, rust prevention treatment or improvement of adhesion.

[ Circuit Board ]

(first embodiment)

The circuit board according to the embodiment of the present invention is obtained by wiring the metal layer of the metal-clad laminate according to any of the above-described embodiments. A circuit board such as an FPC can be manufactured by patterning one or more metal layers of a metal-clad laminate by a conventional method to form wiring layers (conductor circuit layers). Further, the circuit substrate may include a cover film covering the wiring layer.

(second embodiment)

For example, as shown in fig. 5, a circuit board 200 according to another embodiment of the present invention includes: a first substrate 11; a wiring layer 50 laminated on at least one surface of the first base material 11; and an adhesive layer 20 laminated on the surface of the first base material 11 on the wiring layer 50 side so as to cover the wiring layer 50, the adhesive layer 20 including the adhesive film. The circuit board 200 may include any layer other than the above layers.

The first base material 11 in the circuit substrate 200 may have the same structure as the insulating resin layer of the metal clad laminate. The circuit substrate 200 may be manufactured as follows: an adhesive film is bonded to a wiring layer 50 side of a circuit board including a first base material 11 and a wiring layer 50 laminated on at least one surface of the first base material 11.

(third embodiment)

As shown in fig. 6, for example, a circuit board 201 according to still another embodiment of the present invention includes: a first substrate 11; a wiring layer 50 laminated on at least one surface of the first base material 11; an adhesive layer 20 laminated on the surface of the first base material 11 on the wiring layer 50 side so as to cover the wiring layer 50; and a second base material 12 laminated on the surface of the adhesive layer 20 opposite to the first base material 11, wherein the adhesive layer 20 includes the adhesive film. The circuit board 201 may include any layer other than the above layers. The first base material 11 and the second base material 12 in the circuit board 201 may have the same structure as the insulating resin layer of the metal-clad laminate.

The circuit substrate 201 can be manufactured as follows: the second base material 12 is bonded to the wiring layer 50 side of the circuit board including the first base material 11 and the wiring layer 50 laminated on at least one surface of the first base material 11 with an adhesive film interposed therebetween.

(fourth embodiment)

For example, as shown in fig. 7, a circuit board 202 according to still another embodiment of the present invention includes: a first substrate 11; an adhesive layer 20 laminated on at least one surface of the first base material 11; a second base material 12 laminated on a surface of the adhesive layer 20 opposite to the first base material 11; and wiring layers 50, 50 laminated on the surfaces of the first base material 11 and the second base material 12 opposite to the adhesive layer 20, respectively, and the adhesive layer 20 including the adhesive film. The circuit board 202 may include any layer other than the above layers. The first base material 11 and the second base material 12 in the circuit substrate 202 may have the same structure as the insulating resin layer of the metal-clad laminate.

The circuit substrate 202 may be manufactured as follows: a first circuit board including a first base material 11 and a wiring layer 50 laminated on at least one surface of the first base material 11 and a second circuit board including a second base material 12 and a wiring layer 50 laminated on at least one surface of the second base material 12 are prepared, and an adhesive film is disposed between the first base material 11 of the first circuit board and the second base material 12 of the second circuit board and bonded thereto.

[ multilayer Circuit Board ]

The multilayer circuit board according to an embodiment of the present invention includes a laminate in which a plurality of insulating resin layers are laminated, and one or more wiring layers embedded in the laminate, wherein at least one or more of the plurality of insulating resin layers is formed of an adhesive layer 20 having adhesiveness and covering the wiring layers, and the adhesive layer 20 includes the adhesive film. The multilayer circuit board of the present embodiment may include any layer other than the above layers.

For example, as shown in fig. 8, the multilayer circuit board 203 of the present embodiment includes at least two or more insulating resin layers 34 and at least two or more wiring layers 50, and at least one of the wiring layers 50 is covered with an adhesive layer 20. The adhesive layer 20 covering the wiring layer 50 may partially cover the surface of the wiring layer 50 or may cover the entire surface of the wiring layer 50. The multilayer circuit board 203 may optionally have a wiring layer 50 exposed to the surface of the multilayer circuit board 203. Further, an interlayer connection electrode (via electrode) may be provided in contact with the wiring layer 50. The wiring layer 50 is a layer in which a conductor circuit is formed in a predetermined pattern on one surface or both surfaces of the insulating resin layer 34. The conductor circuit may be a circuit formed by patterning the surface of the insulating resin layer 34, or may be a circuit formed by patterning in a damascene (embedded) manner. The insulating resin layer 34 in the multilayer circuit substrate 203 may be the same structure as that of the metal clad laminate.

Since the circuit board and the multilayer circuit board according to each of the above embodiments include the adhesive layer 20 containing the adhesive polyimide having a controlled aromatic ring concentration, the transmission loss can be reduced even in high-frequency transmission.

[ Effect ]

Fig. 9 is a graph schematically showing the relationship between the aromatic ring concentration and the dielectric loss tangent when the adhesive polyimide of the present invention satisfies the above conditions a, b1, and c. The ordinate of fig. 9 represents the dielectric loss tangent at 10GHz measured by the same method as in the example described later, and the abscissa represents the weight content (aromatic ring concentration) of carbon atoms derived from a 6-membered aromatic ring relative to the total content of all atoms in the polyimide. Aromatic rings such as benzene rings vibrate at high frequency, which increases heat loss. Therefore, as a general tendency, the dielectric loss tangent increases as the concentration of the aromatic ring contained in the polyimide increases. However, it was found that when the aromatic ring concentration of the adhesive polyimide is in the range of 12 to 40% by weight, the dielectric loss tangent does not increase even if the aromatic ring concentration increases, but rather the dielectric loss tangent tends to decrease up to a certain aromatic ring concentration. Although the reason for showing such behavior is not clear, it can be reasonably explained if considered as follows.

The adhesive polyimide is produced from a dimer diamine composition, and has a relatively low aromatic ring concentration as compared with a polyimide produced from an aromatic diamine. Presume that: when the concentration of the aromatic rings is gradually increased from a state where the concentration of the aromatic rings is low as described above, the interaction between the aromatic rings restricts the movement of molecules, and the dielectric loss tangent is suppressed to be lower. Further, it is considered that: the low dielectric loss tangent was sufficiently exhibited until the aromatic ring concentration reached 40 wt%.

[ examples ]

The following examples are provided to more specifically explain the features of the present invention. The scope of the present invention is not limited to the examples. In the following examples, unless otherwise specified, various measurements and evaluations were made as follows.

[ method for measuring amine number ]

About 2g of the dimer diamine composition was weighed into a 200-250 mL Erlenmeyer flask, and 0.1mol/L ethanolic potassium hydroxide solution was added dropwise using phenolphthalein as an indicator until the solution became pale pink, and the solution was dissolved in about 100mL of neutralized butanol. Adding 3-7 drops of phenolphthalein solution, and titrating with 0.1mol/L ethanolic potassium hydroxide solution while stirring until the solution of the sample becomes light pink. 5 drops of bromophenol blue solution were added thereto, and titration was performed with 0.2mol/L hydrochloric acid/isopropyl alcohol solution while stirring until the sample solution became yellow.

The amine value is calculated by the following formula (1).

Amine value { (V)₂×C₂)-(V₁×C₁)}×M_KOH/m…(1)

Here, the amine value is the value expressed in mg-KOH/g, M_KOHIs the molecular weight of 56.1 for potassium hydroxide. V, C denotes the volume and concentration of the solution used for the titration, and subscripts 1 and 2 denote 0.1mol/L ethanolic potassium hydroxide solution and 0.2mol/L hydrochloric acid/isopropyl alcohol solution, respectively. Further, m is a sample weight expressed in grams (gram).

[ measurement of weight average molecular weight (Mw) of polyimide ]

The weight average molecular weight was measured by Gel Permeation chromatography (Gel Permeation chromatography) (HLC-8220 GPC manufactured by Tosoh (TOSOH) Co., Ltd.). Polystyrene was used as a standard substance, and Tetrahydrofuran (THF) was used as a developing solvent.

[ method for calculating CM value ]

The weight content (C) is determined by the weight average molecular weight (Mw) of the polyimide and the weight content of carbon atoms derived from a 6-membered aromatic ring (excluding carbon atoms derived from a 6-membered aromatic ring of the dimer diamine composition) relative to the total content of all atoms in the polyimide_p) And calculating the CM value based on the following expression.

CM＝(C_p/Mw)×10⁴…(i)

[ method for calculating DM value ]

According to the weight average molecular weight (Mw) of the polyimide in combination with carbon atoms derived from a 6-membered aromatic ring (derived from dimer diamineCarbon atom of 6-membered aromatic ring of the compound) relative to the total content of all atoms in all diamine components (C)_d) And calculating the DM value based on the following expression.

DM＝(C_d/Mw)×10⁴…(ii)

[ calculation of aromatic Ring ratio of dimer diamine composition ]

The aromatic ring ratio of the dimer diamine composition was calculated according to the following procedure. First, about 50. mu.l of the dimer diamine composition was dissolved in THF-d 8550. mu.l to prepare a sample. For the prepared sample, liquid 1H-NMR measurement was performed at room temperature using an FT-NMR apparatus (JNM-ECA 400 manufactured by JEOL). An integrated value based on 1H peaks observed at 6.6ppm to 7.2ppm derived from aromatic rings relative to 1H peaks observed at 2.6ppm to 2.9ppm derived from direct bonding to NH₂Basic CH₂The ratio of the integrated values of the 1H peak values of the radicals was calculated as follows.

Aromatic ring ratio [ mol% ] ═ Z/Y). times.100

Here, Y is an integrated value of 1H peak at 2.6ppm to 2.9ppm, and Z is an integrated value of 1H peak (derived from aromatic ring) at 6.6ppm to 7.2 ppm.

[ calculation of GPC and area percentage of chromatogram ]

(a) Dimer diamines

(b) Monoamine compound obtained by substituting terminal carboxylic acid group of monoacid compound having carbon number within the range of 10-40 with primary aminomethyl or amino group

(c) An amine compound obtained by substituting a terminal carboxylic acid group of a polybasic acid compound having a hydrocarbon group with a carbon number in the range of 41 to 80 with a primary aminomethyl group or an amino group (wherein the dimer diamine is excluded)

Regarding GPC, a100 mg solution obtained by pretreating 20mg of a dimer diamine composition with 200 μ L of acetic anhydride, 200 μ L of pyridine, and 2mL of THF was diluted with 10mL of THF (containing 1000ppm of cyclohexanone) to prepare a sample. For the prepared samples, trade names manufactured by Tosoh (TOSOH) GmbH were used: HLC-8220GPC on column: TSK-gel G2000HXL, G1000HXL, flow: 1mL/min, column (oven) temperature: 40 ℃, injection amount: the measurement was carried out under the condition of 50. mu.L. Furthermore, cyclohexanone was treated as a standard substance for correcting the outflow time.

In this case, the components (a) to (c) were detected under conditions that the peak top retention time (retention time) of the main peak of cyclohexanone was adjusted so as to be 31 minutes from 27 minutes and the peak start to peak end of the main peak of cyclohexanone was adjusted so as to be 2 minutes, and the peak tops of the main peaks other than the peak of cyclohexanone were adjusted so as to be 19 minutes from 18 minutes and the peak start to peak end of the main peaks other than the peak of cyclohexanone were adjusted so as to be 4 minutes to 30 seconds from 2 minutes,

(a) the component represented by the main peak;

(b) a component represented by a GPC peak detected at a later time than the minimum value on the time side where the retention time of the main peak is later;

(c) a component represented by a GPC peak detected at a time earlier than the minimum value on the time side where the retention time is earlier in the main peak.

[ measurement of viscosity ]

Using a viscometer of type E (model DV-II + ProCP), the ratio between the temperature: 25 ℃ and rotation speed: 100RPM, measurement time: the viscosity (cP) immediately after polymerization was measured under the condition of 2 minutes.

[ measurement of relative dielectric constant and dielectric loss tangent ]

Using a Vector Network Analyzer (Vector Network Analyzer) (manufactured by Agilent, trade name: Vector Network Analyzer E8363C) and SPDR, a resin sheet was subjected to a temperature of 23 ℃, humidity: after 50% of the solution was left to stand for 24 hours, the relative dielectric constant (. epsilon.) at a frequency of 10GHz was measured₁) And dielectric loss tangent (Tan. delta.)₁) And the relative dielectric constant (. epsilon.) at a frequency of 20GHz₂) And dielectric loss tangent (Tan. delta.)₂). Further, the R value which is an index of the frequency dependence of the dielectric loss tangent is calculated by the following formula.

R value is Tan delta₂-Tanδ₁

[ glass transition temperature (Tg) ]

The glass transition temperature (Tg) was measured at a temperature rise rate of 5 ℃/min from 0 ℃ to 300 ℃ with respect to a resin sheet having a size of 5mm × 20mm using a thermomechanical analyzer (TMA (thermal Mechanical analyzer): product of Nachi (NETZSCH) Inc., trade name: TMA4000 SA). The temperature at the inflection point of the elongation at the time of temperature increase was defined as the glass transition temperature.

[ tensile elastic modulus ]

The tensile modulus was measured according to the following procedure. First, a test piece (width 12.7 mm. times. length 127mm) was produced from a resin sheet using a tensile tester (trade name: Tencilon, manufactured by Orien Tak (ORIENTEC)). Using the test piece, a tensile test was conducted at 50mm/min to determine the tensile elastic modulus at 25 ℃.

[ evaluation method of warpage ]

The warpage was evaluated in the following manner. The polyimide solution was applied to a polyimide film (trade name: Kapton (Kapton)100EN, manufactured by Toray Dupont) having a thickness of 25 μm or a copper foil having a thickness of 12 μm so that the thickness of the polyimide solution after drying became 25 μm, to prepare a test piece. In this state, the test piece was placed so that the polyimide film or the copper foil became the lower surface, and the average height of the warpage of the four corners of the test piece was measured, and it was assumed that 5mm or less was "good" and that it was "impossible" when it exceeded 5 mm.

The abbreviations used in the examples represent the following compounds.

BTDA: 3,3',4,4' -benzophenone tetracarboxylic dianhydride

BPDA: 3,3',4,4' -biphenyltetracarboxylic dianhydride

ODPA: 4,4' -oxydiphthalic anhydride

BPADA: 2,2-bis [4- (3,4-dicarboxyphenoxy) phenyl ] propane dianhydride

DDA: a mixture of dimer diamine having 36 carbon atoms (a compound obtained by distilling and purifying Polypri allergy (PRIAMINE)1074, a trade name of which is manufactured by Croda Japan, Ltd., amine value: 210mgKOH/g, cyclic structure and chain structure), component (a) 97.9 area%, component (b) 0.3 area%, component (c) 1.8 area%, and aromatic ring ratio: 8.2 mol%)

BAFL: dianiline fluorenes

APB: 1,3-bis (3-aminophenoxy) benzene

BAPP: 2,2-bis [4- (4-aminophenoxy) phenyl ] propane

N-12: dodecanedioic acid dihydrazide

NMP: n-methyl-2-pyrrolidone

OP 935: aluminum salt of phosphinic acid (trade name: Exxolite (Exolit) OP935, manufactured by Clariant corporation, aluminum diethylphosphinate, phosphorus content: 23%, average particle diameter D₅₀：2μm)

SR-3000: phosphoric ester (trade name: SR-3000, non-halogenated aromatic condensed phosphoric ester, phosphorus content: 7.0%, manufactured by Daba chemical industries, Ltd.)

The molecular weight of DDA is calculated by the following formula.

Molecular weight 56.1X 2X 1000/amine number

Example A1

A1000 ml separable flask was charged with 46.43g of BTDA (0.1441 mol), 68.60g of DDA (0.1284 mol), 4.97g of BAFL (0.0143 mol), 168g of NMP and 112g of xylene, and thoroughly mixed at 40 ℃ for 1 hour to prepare a polyamic acid solution. The polyamic acid solution was heated to 190 ℃ and stirred for 5 hours, and 98g of xylene was added to prepare an imidized polyimide solution A1 (solid content: 30% by weight, weight-average molecular weight: 28,850, 6-membered aromatic ring content C)_d：5.59％、C_p: 21.57%, DM value: 1.9, CM value: 7.5).

Example A2 to example A18

Polyimide solutions a2 to a18 were prepared in the same manner as in example a1, except that the raw material compositions shown in table 1 and table 2 were used.

[ Table 1]

[ Table 2]

Example A19

The polyimide solution a1 was applied to one surface of a release polyethylene terephthalate (PET) film 1 (product name: HY-S05, vertical x horizontal x thickness of 200mm x 300mm x 25 μm, manufactured by east mountain film corporation), and dried at 120 ℃ for 10 minutes to peel the adhesive layer from the release PET film 1, thereby obtaining an adhesive film a19 having a thickness of 25 μm. The evaluation results of the adhesive film a19 are as follows.

ε₁：2.6、Tanδ₁：0.0017、ε₂：2.6、Tanδ₂: 0.0014, R value: -0.0003, Tg: tensile modulus at 45 ℃: 630MPa

Example A20 to example A36

Adhesive film a20 to adhesive film a36 were obtained in the same manner as in example a19, except that polyimide solution a2 to polyimide solution a18 were used. The results of evaluation of various properties are shown in table 3.

[ Table 3]

Example A37

An adhesive composition A37 was prepared by adding 1.1g of N-12(0.004 mol) to 100g of polyimide solution A1 (30 g in terms of solid content), adding 7.5g of OP935, 2.0g of NMP and 12.0g of xylene to dilute the mixture, and further stirring the mixture for 1 hour.

Example A38 to example A54

Adhesive compositions a38 to a54 were prepared in the same manner as in example a37, except that the polyimide solutions a2 to a18 were used.

Example A55

An adhesive composition A55 was prepared by adding 0.6g of N-12(0.002 mol) to 100g of a polyimide solution A17 (30 g in terms of solid content), adding 7.5g of OP935, 1.5g of NMP and 11.4g of xylene to dilute the mixture, and further stirring the mixture for 1 hour.

Example A56

An adhesive composition A56 was prepared by adding 1.1g of N-12(0.004 mol) to 100g of polyimide solution A11 (30 g in terms of solid content), adding 6.0g of SR-3000, 0.3g of NMP and 10.3g of xylene to dilute the mixture, and further stirring the mixture for 1 hour.

Example A57

Adhesive composition a37 was applied to one surface of release PET film 1, and dried at 80 ℃ for 15 minutes to obtain resin sheet a57 with an adhesive layer thickness of 25 μm, and the adhesive layer was peeled from release PET film 1 to obtain adhesive film a57 with a thickness of 25 μm.

Example A58 to example A76

Resin sheets a58 to a76, and adhesive films a58 to a76 were obtained in the same manner as in example a57, except that the adhesive compositions a38 to a56 were used.

Example A77

The adhesive composition A37 was applied to a polyimide film 1 (manufactured by Toray Dupont, Inc.; trade name: Kapton (Kapton)50EN, ε₁＝3.6、tanδ₁0.0084, 200mm × 300mm × 12 μm in length × width), and dried at 80 ℃ for 15 minutes to obtain a cover film a77 having an adhesive layer thickness of 25 μm. The warp state of the obtained cover film a77 was "good".

Example A78 to example A81

Coverlay films a78 to a81 were obtained in the same manner as in example a77, except that adhesive composition a40, adhesive composition a54, adhesive composition a55, and adhesive composition a56 were used. The warp states of the obtained cover films a78 to a81 were all "good".

Example A82

The release PET film 1 was laminated so as to be in contact with the adhesive layer side of the cover film a77, and was pressed for 2 minutes at a temperature of 160 ℃ and a pressure of 0.8MPa using a vacuum laminator. Then, the adhesive composition a37 was applied to the polyimide film 1 side of the coverlay a77 in which the release PET film 1 was laminated on the adhesive layer side so that the dried thickness became 25 μm, and dried at 80 ℃ for 15 minutes. Then, the release PET film 1 was laminated so as to be in contact with the surface to which the adhesive composition a37 was applied and dried, and was pressure-bonded for 2 minutes at 160 ℃ and 0.8MPa using a vacuum laminator, to obtain a laminate a82 with a polyimide adhesive layer, in which adhesive layers were provided on both surfaces of the polyimide film.

Example A83 to example A86

A polyimide adhesive layer-attached laminate a83 to a polyimide adhesive layer-attached laminate a86 were obtained in the same manner as in example a82, except that the coverlay a78, the coverlay a79, the coverlay a80, or the coverlay a81 was used, and the adhesive composition a40, the adhesive composition a54, the adhesive composition a55, or the adhesive composition a56 was applied.

Example A87

The adhesive composition A37 was applied to one surface of an electrolytic copper foil having a thickness of 12 μm, and dried at 80 ℃ for 15 minutes to obtain a resin-attached copper foil A87 having an adhesive layer thickness of 25 μm. The warp state of the obtained resin-attached copper foil a87 was "good".

Example A88 to example A91

Resin-attached copper foils a88 to a resin-attached copper foil a91 were obtained in the same manner as in example a87, except that the adhesive composition a40, the adhesive composition a54, the adhesive composition a55, or the adhesive composition a56 was used. The warpage states of the obtained resin-attached copper foils a88 to a91 were all "good".

Example A92

The adhesive composition A37 was applied to one surface of an electrolytic copper foil having a thickness of 12 μm, and dried at 80 ℃ for 30 minutes to obtain a resin-attached copper foil A92 having an adhesive layer thickness of 50 μm. The warp state of the obtained resin-attached copper foil a92 was "good".

Example A93

The surface of the adhesive layer of the resin-attached copper foil a92 was further coated with an adhesive composition a37, and dried at 80 ℃ for 30 minutes to obtain a resin-attached copper foil a93 having a total adhesive layer thickness of 100 μm. The warp state of the obtained resin-attached copper foil a93 was "good".

Example A94

Adhesive composition a37 was applied to one surface of release PET film 1, and dried at 80 ℃ for 30 minutes to peel the adhesive layer from release PET film 1, thereby obtaining adhesive film a94 having a thickness of 50 μm.

An adhesive film A94 and a polyimide film 2 (trade name: Kapton (Kapton)100-EN, thickness 25 μm,. epsilon.) were laminated in this order on an electrodeposited copper foil with a thickness of 12 μm₁＝3.6、tanδ₁0.0084), an adhesive film a94, and an electrodeposited copper foil with a thickness of 12 μm, were pressed for 2 minutes at a temperature of 160 ℃ and a pressure of 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 ℃ and heat-treated at 160 ℃ for 4 hours to obtain a copper-clad laminate a 94.

Example A95 to example A98

Copper-clad laminates a95 to a copper-clad laminate a98 were obtained in the same manner as in example a94, except that the adhesive composition a40, the adhesive composition a54, the adhesive composition a55, and the adhesive composition a56 were used.

Example A99

An electrolytic copper foil having a thickness of 12 μm was laminated so that the adhesive layer side of the coverlay film a77 was in contact with the copper foil, and the resultant was pressed for 2 minutes at 160 ℃ and 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 ℃ and heat-treated at 160 ℃ for 2 hours to obtain a copper-clad laminate a 99.

Example A100 to example A103

Copper-clad laminates a100 to a103 were obtained in the same manner as in example a99, except that the coverlay films a78, a79, a80, and a81 were used.

Example A104

An adhesive film a57 was laminated on a rolled copper foil having a thickness of 12 μm, the rolled copper foil having a thickness of 12 μm was laminated so that the polyimide film 1 side of the coverlay a77 was in contact with the adhesive film a57, and further a rolled copper foil having a thickness of 12 μm was laminated in order on the adhesive layer side of the coverlay a77, and was pressed and bonded at a temperature of 160 ℃ and a pressure of 0.8MPa for 2 minutes using a vacuum laminator, followed by heating from room temperature to 160 ℃ and heat treatment at 160 ℃ for 2 hours, to obtain a copper-clad laminate a 104.

Example A105 to example A108

Copper-clad laminates a105 to a108 were produced in the same manner as in example a104, except that the adhesive film a60, the adhesive film a74, the adhesive film a75, and the adhesive film a76 were used instead of the adhesive film a57, and the coverlay films a78, a79, a80, and a81 were used instead of the coverlay film a 77.

[ example A109]

Two resin-coated copper foils A93 were prepared, and a polyimide film 3 (manufactured by DuPont, Inc., trade name: Kapton (Kapton)200-EN, thickness 50 μm,. epsilon.)₁＝3.6、tanδ₁0.0084) was laminated so as to contact the adhesive layer side of the two resin-coated copper foils a93, and the resultant was pressed for 5 minutes at 160 ℃ and a pressure of 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 ℃ and heat-treated at 160 ℃ for 4 hours to obtain a copper-clad laminate a 109.

[ example A110]

The adhesive composition a55 was applied to the resin layer (polyimide layer) side of a single-sided copper-clad laminate 1 (available from Chemical & materials corporation under the trade name: Espanex MC12-25-00UEM, 200mm × 300mm × 25 μm in vertical × horizontal × thickness) and dried at 80 ℃ for 30 minutes to obtain an adhesive layer-attached copper-clad laminate a110 having an adhesive layer thickness of 50 μm. The other single-sided copper-clad laminate 1 was laminated so that the resin layer side was in contact with the adhesive layer side of the copper-clad laminate with adhesive layer a110, and was pressure-bonded using a small precision press at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a copper-clad laminate a 110.

Example A111

The adhesive layer-side surface was laminated so as to be in contact with two adhesive layer-attached copper-clad laminates a110, and the laminated sheets were pressed together by a small precision press at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain copper-clad laminates a 111.

Example A112

An adhesive film a73 was laminated on the resin layer side of the single-sided copper-clad laminate 1, and further laminated thereon so that the resin layer side of the single-sided copper-clad laminate 1 was in contact with the adhesive film a73, and the resultant was pressure-bonded for 120 minutes at a temperature of 160 ℃ and a pressure of 4.0MPa using a small precision press to obtain a copper-clad laminate a 112.

Example A113

Adhesive composition a37 was applied to one surface of release PET film 1, and dried at 80 ℃ for 15 minutes to peel the adhesive layer from release PET film 1, thereby obtaining adhesive film a113 having a thickness of 15 μm.

The adhesive film a113 was laminated on the resin layer side of the single-sided copper-clad laminate 1, and further laminated thereon so that the adhesive film a113 was in contact with the resin layer side of the single-sided copper-clad laminate 1, and the resulting laminate was pressure-bonded using a small precision press at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a copper-clad laminate a 113.

Example A114

A double-sided copper-clad laminate 2 (product name: Espanex MB12-25-00UEG, manufactured by Chemical & materials) was prepared, and the copper foil on one side was subjected to circuit processing by etching to obtain a wiring board a114A on which a conductor circuit layer was formed.

The copper foil on one side of the double-sided copper-clad laminate 2 was etched away to obtain a copper-clad laminate a 114B.

An adhesive film a73 was interposed between the surface of the wiring board a114A on the conductor circuit layer side and the surface of the copper-clad laminate a114B on the resin layer side, and the resultant laminate was thermocompression bonded at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a multilayer circuit board a 114.

[ example A115]

Prepare a liquid crystal polymer film (Coly (K))uaray) company, trade name: CT-Z, thickness: 50 μm, Coefficient Of Thermal Expansion (CTE): 18ppm/K, Heat distortion temperature: 300 ℃ and epsilon₁＝3.40、tanδ₁0.0022) as an insulating base material, a copper-clad laminate a115 in which electrolytic copper foils having a thickness of 18 μm were provided on both surfaces thereof, and the copper foil on one surface was subjected to circuit processing by etching to obtain a wiring board a115A on which a conductor circuit layer was formed.

The copper foil on one surface of the copper-clad laminate a115 was etched away to obtain a copper-clad laminate a 115B.

An adhesive film a73 was interposed between the surface of the wiring board a115A on the conductive circuit layer side and the surface of the copper-clad laminate a115B on the insulating base layer side, and the resultant laminate was thermocompression bonded at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a multilayer circuit board a 115.

Example B1

A500 ml separable flask was charged with 27.90g of BTDA (0.08642 moles), 6.702g of ODPA (0.02161 moles), 46.50g of DDA (0.08703 moles), 8.932g of BAPP (0.02176 moles), 126g of NMP and 84g of xylene, and thoroughly mixed at 40 ℃ for 1 hour to prepare a polyamic acid solution. The polyamic acid solution was heated to 190 ℃ and stirred for 5 hours, and 60g of xylene was added to prepare an imidized polyimide solution B1 (solid content: 30% by weight, weight-average molecular weight: 35,332, viscosity: 2,627 cP).

Example B2 to example B11

Polyimide solutions B2 to B11 were prepared in the same manner as in example B1, except that the raw material compositions shown in table 4 were used.

[ Table 4]

Example B12

Polyimide solution B1 was applied to one surface of release PET film 1 (product name: HY-S05, product name: 200mm × 300mm × 25 μm in vertical × horizontal × thickness manufactured by east mountain film corporation), dried at 100 ℃ for 5 minutes, then dried at 120 ℃ for 5 minutes, and the adhesive layer was peeled off from release PET film 1, thereby obtaining resin sheet B12 having a thickness of 25 μm. The results of various evaluations of the resin sheet B12 are as follows.

ε₁：2.6、Tanδ₁：0.0017、ε₂：2.6、Tanδ₂: 0.0015, R value: -0.0002, Tg: tensile modulus at 47 ℃: 1230MPa

Example B13 to example B22

Resin sheets B13 to B22 were obtained in the same manner as in example B12, except that the polyimide solutions B2 to B11 were used. The results of evaluation of various properties are shown in table 5.

[ Table 5]

Example B23

An adhesive composition B23 was prepared by adding 1.1g of N-12(0.004 mol) to 100g of the polyimide solution B1 (30 g in terms of solid content), adding 7.5g of OP935, 0.5g of NMP and 10.5g of xylene to dilute the mixture, and further stirring the mixture for 1 hour.

Example B24 to example B33

Adhesive compositions B24 to B33 were prepared in the same manner as in example B23, except that the polyimide solutions B2 to B11 were used.

Example B34

An adhesive composition B34 was prepared by adding 0.6g of N-12(0.002 mol) to 100g of the polyimide solution B9 (30 g in terms of solid content), adding 7.4g of OP935, 1.8g of NMP and 11.7g of xylene to dilute the mixture, and further stirring the mixture for 1 hour.

Example B35

Adhesive composition B23 was applied to one surface of release PET film 1, and dried at 80 ℃ for 15 minutes to obtain resin sheet B35 with an adhesive layer thickness of 25 μm, and the adhesive layer was peeled from release PET film 1 to obtain adhesive film B35 with a thickness of 25 μm.

Example B36 to example B46

Adhesive films B36 to B46 were obtained in the same manner as in example B35, except that the adhesive compositions B24 to B34 were used.

Example B47

The adhesive composition B31 was applied to a polyimide film 1 (manufactured by Toray Dupont, Inc.; trade name: Kapton (Kapton)50EN, ε₁＝3.6、tanδ₁0.0084, 200mm × 300mm × 12 μm in length × width), and dried at 80 ℃ for 15 minutes to obtain a cover film B47 having an adhesive layer thickness of 25 μm. The warp state of the obtained cover film B47 was "good".

Example B48, example B49

A coverlay film B48 and a coverlay film B49 were obtained in the same manner as in example B47, except that the adhesive composition B24 and the adhesive composition B25 were used. The warp states of the obtained cover films B48 and B49 were all "good".

Example B50

The release PET film 1 was laminated so as to be in contact with the adhesive layer side of the cover film B47, and was pressed for 2 minutes at a temperature of 160 ℃ and a pressure of 0.8MPa using a vacuum laminator. Then, the adhesive composition B31 was applied to the polyimide film 1 side of the cover film B47 in which the release PET film 1 was laminated on the adhesive layer side so that the dried thickness became 25 μm, and dried at 80 ℃ for 15 minutes. Then, the release PET film 1 was laminated so as to be in contact with the surface to which the adhesive composition B31 was applied and dried, and was pressure-bonded for 2 minutes at 160 ℃ and 0.8MPa using a vacuum laminator, to obtain a laminate B50 with a polyimide adhesive layer, in which adhesive layers were provided on both surfaces of the polyimide film.

Example B51, example B52

A laminate B51 with a polyimide adhesive layer and a laminate B52 with a polyimide adhesive layer were obtained in the same manner as in example B50, except that the coverlay films B48 and B49 were used and the adhesive compositions B24 and B25 were applied.

Example B53

The adhesive composition B31 was applied to one surface of an electrolytic copper foil having a thickness of 12 μm, and dried at 80 ℃ for 15 minutes to obtain a resin-attached copper foil B53 having an adhesive layer thickness of 25 μm. The warp state of the obtained resin-attached copper foil B53 was "good".

Example B54 to example B56

Resin-attached copper foils B54 to B56 were obtained in the same manner as in example B53, except that adhesive composition B24, adhesive composition B25, and adhesive composition B26 were used. The warpage states of the obtained resin-attached copper foils B54 to B56 were all "good".

Example B57

The adhesive composition B31 was applied to one surface of an electrolytic copper foil having a thickness of 12 μm, and dried at 80 ℃ for 30 minutes to obtain a resin-attached copper foil B57 having an adhesive layer thickness of 50 μm. The warp state of the obtained resin-attached copper foil B57 was "good".

Example B58

Further, an adhesive composition B31 was applied to the surface of the adhesive layer of the resin-attached copper foil B57, and the adhesive layer was dried at 80 ℃ for 30 minutes to obtain a resin-attached copper foil B58 having a total adhesive layer thickness of 100. mu.m. The warp state of the obtained resin-attached copper foil B58 was "good".

Example B59

Adhesive composition B31 was applied to one surface of release PET film 1, and dried at 80 ℃ for 30 minutes to peel the adhesive layer from release PET film 1, thereby obtaining adhesive film B59 having a thickness of 50 μm.

Example B60

An adhesive film B59 and a polyimide film 2 (trade name: Kapton (Kapton)100-EN, thickness: 25 μm,. epsilon.) were laminated in this order on an electrodeposited copper foil having a thickness of 12 μm₁＝3.6、tanδ₁0.0084), an adhesive film B44 and an electrodeposited copper foil with a thickness of 12 μm, press-bonded for 2 minutes at a temperature of 160 ℃ and a pressure of 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 DEGThe resultant was heat-treated at 160 ℃ for 4 hours to obtain a copper-clad laminate B60.

Example B61 to example B63

Copper-clad laminates B61 to B63 were obtained in the same manner as in example B60, except that the adhesive film B36, the adhesive film B37, and the adhesive film B38 were used.

Example B64

An electrolytic copper foil having a thickness of 12 μm was laminated so that the adhesive layer side of the coverlay film B47 was in contact with the copper foil, and the resultant was pressed for 2 minutes at 160 ℃ and 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 ℃ and heat-treated at 160 ℃ for 2 hours to obtain a copper-clad laminate B64.

Example B65, example B66

A copper-clad laminate B65 and a copper-clad laminate B66 were obtained in the same manner as in example B64, except that the coverlay films B48 and B49 were used.

Example B67

An adhesive film B44 was laminated on a rolled copper foil having a thickness of 12 μm, and the rolled copper foil having a thickness of 12 μm was laminated so that the polyimide film side of the coverlay film B47 was in contact with the adhesive film B44, and further, a rolled copper foil having a thickness of 12 μm was laminated in this order on the adhesive layer side of the coverlay film B47, and the resultant was pressed for 2 minutes at a temperature of 160 ℃ and a pressure of 0.8MPa using a vacuum laminator, and then heated from room temperature to 160 ℃ and heat-treated at 160 ℃ for 2 hours, to obtain a copper-clad laminate B67.

Example B68, example B69

A copper-clad laminate B68 and a copper-clad laminate B69 were produced in the same manner as in example B67, except that the adhesive film B35 and the adhesive film B36 were used instead of the adhesive film B44, and the coverlay film B48 and the coverlay film B49 were used instead of the coverlay film B47.

Example B70

Two resin-coated copper foils B57 were prepared, and a polyimide film 3 (manufactured by DuPont, Inc., trade name: Kapton (Kapton)200-EN, thickness 50 μm,. epsilon.)₁＝3.6、tanδ₁0.0084) was laminated so as to contact the adhesive layer side of the two resin-coated copper foils B57, and a vacuum laminator was used at 160 ℃ and a pressureAnd (3) pressing at 0.8MPa for 5 minutes, then heating from room temperature to 160 ℃, and carrying out heat treatment at 160 ℃ for 4 hours to obtain the copper-clad laminate B70.

Example B71

The adhesive composition B31 was applied to the resin layer (polyimide layer) side of a single-sided copper-clad laminate 1 (manufactured by ferrite Chemical (Chemical & Material)) with a trade name of Espanex MC12-25-00UEM and a longitudinal x transverse x thickness of 200mm x 300mm x 25 μm, and dried at 80 ℃ for 30 minutes to obtain an adhesive layer-attached copper-clad laminate B71 with an adhesive layer thickness of 50 μm. The other single-sided copper-clad laminate 1 was laminated so that the resin layer side was in contact with the adhesive layer side of the copper-clad laminate B71 with an adhesive layer, and was pressure-bonded using a small precision press at 160 ℃ and 4.0MPa for 120 minutes to obtain a copper-clad laminate B71.

Example B72

The adhesive layer-side surface was laminated so as to be in contact with two adhesive layer-attached copper-clad laminates B71, and the laminated sheets were pressure-bonded for 120 minutes at 160 ℃ and 4.0MPa using a small precision press to obtain a copper-clad laminate B72.

Example B73

An adhesive film B44 was laminated on the resin layer side of the single-sided copper-clad laminate 1, and further laminated thereon so that the resin layer side of the single-sided copper-clad laminate 1 was in contact with the adhesive film B44, and the resultant was pressure-bonded for 120 minutes at a temperature of 160 ℃ and a pressure of 4.0MPa using a small precision press, to obtain a copper-clad laminate B73.

Example B74

Adhesive composition B31 was applied to one surface of release PET film 1, dried at 80 ℃ for 15 minutes, and the adhesive layer was peeled from release PET film 1, thereby obtaining adhesive film B74 having a thickness of 15 μm.

Example B75

An adhesive film B74 was laminated on the resin layer side of the single-sided copper-clad laminate 1, and further laminated thereon so that the resin layer side of the single-sided copper-clad laminate 1 was in contact with the adhesive film B74, and the resultant was pressure-bonded for 120 minutes at a temperature of 160 ℃ and a pressure of 4.0MPa using a small precision press, to obtain a copper-clad laminate B75.

Example B76

A double-sided copper-clad laminate 2 (product name: Espanex MB12-25-00UEG, manufactured by Chemical & materials) was prepared, and the copper foil on one side was subjected to circuit processing by etching to obtain a wiring board B76A on which a conductor circuit layer was formed.

The copper foil on one side of the double-sided copper-clad laminate 2 was etched away to obtain a copper-clad laminate B76B.

An adhesive film B44 was interposed between the surface of the wiring board B76A on the conductor circuit layer side and the surface of the copper-clad laminate B76B on the resin layer side, and the laminated layers were thermocompression bonded at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a multilayer circuit board B76.

Example B77

A liquid crystal polymer film (product name: CT-Z, thickness: 50 μm, CTE: 18ppm/K, heat distortion temperature: 300 ℃ C.,. epsilon.) (manufactured by Kuraray, Inc.) was prepared₁＝3.40、tanδ₁0.0022) as an insulating base material, a copper-clad laminate B77 was formed by providing electrolytic copper foils having a thickness of 18 μm on both sides thereof, and circuit processing was performed on the copper foil on one side by etching to obtain a wiring board B77A on which a conductor circuit layer was formed.

The copper foil on one surface of the copper-clad laminate B77 was etched away to obtain a copper-clad laminate B77B.

An adhesive film B44 was interposed between the surface of the wiring board B77A on the conductive circuit layer side and the surface of the copper-clad laminate B77B on the insulating base layer side, and the laminated layers were thermocompression bonded at a temperature of 160 ℃ and a pressure of 4.0MPa for 120 minutes to obtain a multilayer circuit board B77.

While the embodiments of the present invention have been described in detail for the purpose of illustration, the present invention is not limited to the embodiments and can be variously modified.