1. A laminate comprising a base, a release layer, and a resin substrate laminated in this order,

the releasability of the release layer from the base is smaller than the releasability of the release layer from the resin substrate,

the release layer is formed from a release layer-forming composition containing: a polyamic acid obtained by reacting an aromatic diamine with an aromatic tetracarboxylic dianhydride, and an organic solvent,

the aromatic tetracarboxylic dianhydride includes an aromatic tetracarboxylic dianhydride containing an ester bond.

2. The laminate according to claim 1, wherein the aromatic tetracarboxylic dianhydride containing an ester bond is at least 1 selected from the group consisting of formulae (B1) to (B14),

3. the laminate according to claim 1 or 2, wherein the aromatic diamine further comprises an aromatic diamine containing an ester bond.

4. The laminate according to claim 3, wherein the aromatic diamine having an ester bond is at least 1 member selected from the group consisting of formulae (A4) to (A6), (A13) to (A24) and (A34) to (A39),

5. the laminate according to claim 1 or 2, wherein the aromatic tetracarboxylic dianhydride further comprises an aromatic tetracarboxylic dianhydride which does not contain any one of an ester bond and an ether bond.

6. The laminate according to claim 5, wherein the aromatic tetracarboxylic dianhydride which does not contain any of an ester bond and an ether bond contains a benzene skeleton, a naphthyl skeleton or a biphenyl skeleton.

7. The laminate according to claim 6, wherein the aromatic tetracarboxylic dianhydride not containing any one of an ester bond and an ether bond is at least 1 selected from the group consisting of formulae (C1) to (C12),

8. the laminate according to claim 1 or 2, wherein the organic solvent comprises at least one selected from the group consisting of an amide represented by formula (S1), an amide represented by formula (S2), and an amide represented by formula (S3),

in the formula, R¹And R²Independently represent an alkyl group having 1 to 10 carbon atoms, R³Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and h represents a natural number.

9. A method for manufacturing a flexible electronic device having a resin substrate, characterized by using the laminate according to any one of claims 1 to 8.

10. A method for manufacturing a touch panel sensor having a resin substrate, characterized by using the laminate according to any one of claims 1 to 8.

11. The manufacturing method according to claim 8 or 9, wherein the resin substrate is a substrate made of polyimide.

Background

In recent years, electronic devices are required to have a function of bending, and performance of thinning and weight reduction. Therefore, it is required to use a lightweight flexible plastic substrate instead of a conventional heavy, fragile, and inflexible glass substrate. In addition, in the case of new-generation displays, development of active full-color (active full-color) TFT display panels using a lightweight flexible plastic substrate is required. Therefore, various methods for manufacturing electronic devices using a resin film as a substrate have been studied, and in the case of a new-generation display, a process capable of using an existing TFT device has been studied.

Patent documents 1,2, and 3 disclose the following methods: after an amorphous silicon thin film layer is formed on a glass substrate and a plastic substrate is formed on the thin film layer, the plastic substrate is peeled from the glass substrate by hydrogen gas generated by crystallization of amorphous silicon by irradiation with laser light from the glass surface side. Further, patent document 4 discloses a method of: a layer to be peeled (described as a "layer to be transferred" in patent document 4) is attached to a plastic film by using the techniques disclosed in patent documents 1 to 3, thereby completing a liquid crystal display device.

However, the methods disclosed in patent documents 1 to 4, particularly the method disclosed in patent document 4, require the use of a substrate having high light transmittance, and give sufficient energy for releasing hydrogen contained in amorphous silicon through the substrate, and therefore require relatively large irradiation of laser light, which causes a problem of damaging the layer to be peeled. Further, since the laser processing requires a long time, it is difficult to peel off a layer to be peeled having a large area, and thus there is also a problem that it is difficult to improve the productivity of device fabrication.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 10-125929

Patent document 2: japanese laid-open patent publication No. 10-125931

Patent document 3: international publication No. 2005/050754

Patent document 4: japanese laid-open patent publication No. 10-125930

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a composition for forming a release layer that can be peeled off without damaging a resin substrate of a flexible electronic device.

Means for solving the problems

The present inventors have made extensive studies to solve the above problems, and as a result, have found that: in the case of a composition comprising a polyamic acid obtained by reacting an aromatic diamine with an aromatic tetracarboxylic dianhydride, and an organic solvent, wherein the aromatic diamine comprises an aromatic diamine containing at least one of an ester bond and an ether bond, and/or the aromatic tetracarboxylic dianhydride comprises an aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond, a composition capable of forming a release layer having excellent adhesion to a substrate, appropriate adhesion to a resin substrate used as a flexible electronic device, and appropriate releasability is obtained, and the present invention has been completed.

Namely, the present invention provides:

1. a composition for forming a release layer, comprising: a polyamic acid obtained by reacting an aromatic diamine with an aromatic tetracarboxylic dianhydride, and an organic solvent, wherein the aromatic diamine comprises an aromatic diamine containing at least one of an ester bond and an ether bond, and/or the aromatic tetracarboxylic dianhydride comprises an aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond,

2.1 the composition for forming a release layer, wherein the aromatic diamine containing at least one of an ester bond and an ether bond is at least 1 member selected from the group consisting of formulae (A1) to (A42),

[ solution 1]

[ solution 2]

[ solution 3]

[ solution 4]

[ solution 5]

[ solution 6]

[ solution 7]

3.1 or 2, wherein the aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond is at least 1 selected from the group consisting of formulae (B1) to (B14),

[ solution 8]

4.1 to 3, wherein the aromatic tetracarboxylic dianhydride further comprises an aromatic tetracarboxylic dianhydride not containing any one of an ester bond and an ether bond,

5.4 the composition for forming a release layer, wherein the aromatic tetracarboxylic dianhydride not containing any of an ester bond and an ether bond contains a benzene skeleton, a naphthyl skeleton or a biphenyl skeleton,

6.5 the release layer-forming composition, wherein the aromatic tetracarboxylic dianhydride not containing any of an ester bond and an ether bond is at least 1 selected from the group consisting of formulae (C1) to (C12),

[ solution 9]

7.1 to 6, wherein the organic solvent contains at least 1 selected from the group consisting of an amide represented by the formula (S1), an amide represented by the formula (S2), and an amide represented by the formula (S3),

[ solution 10]

(in the formula, R¹And R²Independently represent an alkyl group having 1 to 10 carbon atoms. R³Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. h represents a natural number. )

8. A release layer formed using the release layer-forming composition of any one of 1 to 7,

9. a method for manufacturing a flexible electronic device having a resin substrate, characterized in that a release layer of 8 is used,

10. a method for manufacturing a touch panel sensor having a resin substrate, characterized in that a 8-layer release sheet is used,

11.9 or 10, wherein the resin substrate is a substrate made of polyimide.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the composition for forming a release layer of the present invention, a film having excellent adhesion to a base, appropriate adhesion to a resin substrate, and appropriate releasability can be obtained with good reproducibility. By using the composition of the present invention, in the production process of a flexible electronic device, the resin substrate formed on a base body and further a circuit or the like provided thereon can be separated from the base body together with the circuit or the like without causing damage to the resin substrate. Therefore, the composition for forming a release layer of the present invention can contribute to simplification of the manufacturing process of a flexible electronic device having a resin substrate, improvement of the yield thereof, and the like.

Drawings

Fig. 1 is a graph showing the transmittance measured in example 4.

Detailed Description

The present invention is described in more detail below.

The composition for forming a release layer of the present invention comprises a polyamic acid obtained by reacting an aromatic diamine and an aromatic tetracarboxylic dianhydride, and an organic solvent, wherein the aromatic diamine comprises an aromatic diamine containing at least one of an ester bond and an ether bond, and/or the aromatic tetracarboxylic dianhydride comprises an aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond. Among them, the peeling layer in the present invention is a layer provided for a predetermined purpose directly above a glass substrate, and typical examples thereof include: in a manufacturing process of a flexible electronic device, a layer is provided between a base and a resin substrate of the flexible electronic device made of a resin such as polyimide in order to fix the resin substrate in a predetermined process and in order to easily peel the resin substrate from the base after forming an electronic circuit or the like on the resin substrate.

The aromatic diamine containing at least one of an ester bond and an ether bond contains one of an ester bond and an ether bond or both of them in its molecule.

Examples of the aromatic diamine include diamines having a structure in which a plurality of aromatic rings having 6 to 20 carbon atoms are connected by an ester bond or an ether bond. Specific examples of the aromatic ring include benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, and the like. Among them, from the viewpoint of ensuring the solubility of polyamic acid in an organic solvent, a diamine having a structure in which 2 or 3 aromatic rings are linked by an ester bond or an ether bond is preferable.

In the present invention, preferred specific examples of the aromatic diamine containing at least one of an ester bond and an ether bond include the aromatic diamines shown below.

[ solution 11]

[ solution 12]

[ solution 13]

[ solution 14]

[ solution 15]

[ solution 16]

[ solution 17]

The aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond is an aromatic tetracarboxylic dianhydride containing one of an ester bond and an ether bond in a molecule thereof or an aromatic tetracarboxylic dianhydride containing both an ester bond and an ether bond.

Examples of the aromatic tetracarboxylic dianhydride include tetracarboxylic dianhydrides having a structure in which a plurality of aromatic rings having 6 to 20 carbon atoms are connected by ester bonds or ether bonds. Specific examples of the aromatic ring include the same aromatic rings as described above. Among them, tetracarboxylic dianhydrides having a structure in which 3 or 4 aromatic rings are linked by an ester bond or an ether bond are preferable from the viewpoint of ensuring the solubility of polyamic acid in an organic solvent.

In the present invention, preferred specific examples of the aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond include the following specific examples.

[ solution 18]

In the present invention, other diamines may be used together with the above aromatic diamine containing at least one of an ester bond and an ether bond.

The diamine may be either an aliphatic diamine or an aromatic diamine, but from the viewpoint of ensuring the strength and heat resistance of the resulting film, an aromatic diamine containing no ester bond or ether bond is preferred.

Specific examples thereof include 1, 4-diaminobenzene (p-phenylenediamine), 1, 3-diaminobenzene (m-phenylenediamine), 1, 2-diaminobenzene (o-phenylenediamine), 2, 4-diaminotoluene, 2, 5-diaminotoluene, 2, 6-diaminotoluene, 4, 6-dimethyl-m-phenylenediamine, 2, 5-dimethyl-p-phenylenediamine, 2, 6-dimethyl-p-phenylenediamine, 2,4, 6-trimethyl-1, 3-phenylenediamine, 2,3,5, 6-tetramethyl-p-phenylenediamine, m-xylylenediamine, p-xylylenediamine, 5-trifluoromethylbenzene-1, 3-diamine, 5-trifluoromethylbenzene-1, 2-diamine, m-xylylenediamine, p-xylylenediamine, and the like, Diamines having 1 benzene nucleus such as 3, 5-bis (trifluoromethyl) benzene-1, 2-diamine; 1, 2-naphthalenediamine, 1, 3-naphthalenediamine, 1, 4-naphthalenediamine, 1, 5-naphthalenediamine, 1, 6-naphthalenediamine, 1, 7-naphthalenediamine, 1, 8-naphthalenediamine, 2, 3-naphthalenediamine, 2, 6-naphthalenediamine, 4' -biphenyldiamine, 2' -bis (trifluoromethyl) -4,4' -diaminobiphenyl, 3' -dimethyl-4, 4' -diaminodiphenylmethane, 3' -dicarboxyl-4, 4' -diaminodiphenylmethane, 3',5,5' -tetramethyl-4, 4' -diaminodiphenylmethane, 4' -diaminobenzanilide, 3' -dichlorobenzidine, 3' -dimethylbenzidine, 2,2' -dimethylbenzidine, 3,3' -diaminodiphenylmethane, 3,4' -diaminodiphenylmethane, 4' -diaminodiphenylmethane, 2-bis (3-aminophenyl) propane, 2-bis (4-aminophenyl) propane, 2-bis (3-aminophenyl) -1,1,1,3,3, 3-hexafluoropropane, 2-bis (4-aminophenyl) -1,1,1,3,3, 3-hexafluoropropane, 3,3' -diaminodiphenylsulfoxide, 3,4' -diaminodiphenylsulfoxide, 4' -diaminodiphenylsulfoxide, 3,3' -bis (trifluoromethyl) biphenyl-4, 4' -diamine, Diamines having 2 benzene nuclei, such as 3,3',5,5' -tetrafluorobiphenyl-4, 4 '-diamine and 4,4' -diaminooctafluorobiphenyl; 1, 5-diaminoanthracene, 2, 6-diaminoanthracene, 9, 10-diaminoanthracene, 1, 8-diaminophenanthrene, 2, 7-diaminophenanthrene, 3, 6-diaminophenanthrene, 9, 10-diaminophenanthrene, 1, 3-bis (3-aminophenyl) benzene, 1, 3-bis (4-aminophenyl) benzene, 1, 4-bis (3-aminophenyl) benzene, 1, 4-bis (4-aminophenyl) benzene, 1, 3-bis (3-aminophenyl sulfide) benzene, 1, 3-bis (4-aminophenyl sulfide) benzene, 1, 4-bis (4-aminophenyl sulfide) benzene, 1, 3-bis (3-aminophenyl sulfone) benzene, 1, 3-bis (4-aminophenyl sulfone) benzene, 1, diamines having 3 benzene nuclei such as 4-bis (4-aminophenylsulfone) benzene, 1, 3-bis [2- (4-aminophenyl) isopropyl ] benzene, 1, 4-bis [2- (3-aminophenyl) isopropyl ] benzene, and 1, 4-bis [2- (4-aminophenyl) isopropyl ] benzene, but the present invention is not limited thereto. These can be used alone in 1 kind, also can be more than 2 kinds of combination use.

In the present invention, when a diamine other than the aromatic diamine is used together with the aromatic diamine having at least one of an ester bond and an ether bond, the amount of the aromatic diamine having at least one of an ester bond and an ether bond is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and further preferably 95 mol% or more of the total diamines. By using such an amount, a film having excellent adhesion to a base, appropriate adhesion to a resin substrate, and appropriate peelability can be obtained with good reproducibility.

In the present invention, tetracarboxylic dianhydrides other than the above-described aromatic tetracarboxylic dianhydrides containing at least one of an ester bond and an ether bond can be used together.

As such tetracarboxylic dianhydrides, aliphatic tetracarboxylic dianhydrides and aromatic tetracarboxylic dianhydrides may be used, but aromatic tetracarboxylic dianhydrides not containing both ester bonds and ether bonds are preferred from the viewpoint of ensuring the strength and heat resistance of the resulting film.

Specific examples thereof include pyromellitic dianhydride, benzene-1, 2,3, 4-tetracarboxylic dianhydride, naphthalene-1, 2,5, 6-tetracarboxylic dianhydride, naphthalene-1, 2,6, 7-tetracarboxylic dianhydride, naphthalene-1, 2,7, 8-tetracarboxylic dianhydride, naphthalene-2, 3,5, 6-tetracarboxylic dianhydride, naphthalene-2, 3,6, 7-tetracarboxylic dianhydride, naphthalene-1, 4,5, 8-tetracarboxylic dianhydride, biphenyl-2, 2',3,3' -tetracarboxylic dianhydride, biphenyl-2, 3,3',4' -tetracarboxylic dianhydride, biphenyl-3, 3',4,4' -tetracarboxylic dianhydride, anthracene-1, 2,3, 4-tetracarboxylic acid dianhydride, anthracene-1, 2,5, 6-tetracarboxylic acid dianhydride, anthracene-1, 2,6, 7-tetracarboxylic acid dianhydride, anthracene-1, 2,7, 8-tetracarboxylic acid dianhydride, anthracene-2, 3,6, 7-tetracarboxylic acid dianhydride, phenanthrene-1, 2,3, 4-tetracarboxylic acid dianhydride, phenanthrene-1, 2,5, 6-tetracarboxylic acid dianhydride, phenanthrene-1, 2,6, 7-tetracarboxylic acid dianhydride, phenanthrene-1, 2,7, 8-tetracarboxylic acid dianhydride, phenanthrene-1, 2,9, 10-tetracarboxylic acid dianhydride, phenanthrene-2, 3,5, 6-tetracarboxylic acid dianhydride, phenanthrene-2, 3,6, 7-tetracarboxylic acid dianhydride, phenanthrene-2, 3,9, 10-tetracarboxylic acid dianhydride, phenanthrene-3, 4,5, 6-tetracarboxylic dianhydride, phenanthrene-3, 4,9, 10-tetracarboxylic dianhydride, and the like, but is not limited thereto. These can be used alone in 1 kind, also can be used in more than 2 kinds combination.

In particular, the aromatic tetracarboxylic dianhydride not containing any of an ester bond and an ether bond is preferably at least 1 selected from the group consisting of formulae (C1) to (C12), and more preferably at least 1 selected from the group consisting of formulae (C1) and (C9), from the viewpoint of ensuring heat resistance.

[ solution 19]

In the present invention, when a tetracarboxylic dianhydride other than the aromatic tetracarboxylic dianhydride is used together with the aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond, the amount of the aromatic tetracarboxylic dianhydride containing at least one of an ester bond and an ether bond is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and still further preferably 95 mol% or more of the total tetracarboxylic dianhydride. By using such an amount, a film having sufficient adhesion to a base, appropriate adhesion to a resin substrate, and appropriate peelability can be obtained with good reproducibility.

The polyamic acid contained in the release layer-forming composition according to the present invention can be obtained by reacting the diamine described above with a tetracarboxylic dianhydride.

The organic solvent used in such a reaction is not particularly limited as long as it does not adversely affect the reaction, and specific examples thereof include m-cresol, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, N-dimethylacetamide, N-dimethylformamide, 3-methoxy-N, N-dimethylpropionamide, 3-ethoxy-N, N-dimethylpropionamide, 3-propoxy-N, N-dimethylpropionamide, 3-isopropoxy-N, N-dimethylpropionamide, 3-butoxy-N, N-dimethylpropionamide, 3-sec-butoxy-N, n-dimethylpropionamide, 3-tert-butoxy-N, N-dimethylpropionamide, γ -butyrolactone, etc. Further, 1 kind of the organic solvent may be used alone or 2 or more kinds may be used in combination.

In particular, the organic solvent used in the reaction is preferably at least 1 selected from the group consisting of amides represented by the formula (S1), amides represented by the formula (S2), and amides represented by the formula (S3), from the viewpoint of sufficiently dissolving the diamine, the tetracarboxylic dianhydride, and the polyamic acid.

[ solution 20]

In the formula, R¹And R²Independently represent an alkyl group having 1 to 10 carbon atoms. R³Represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. h represents a natural number, preferably 1 to 3, and more preferably 1 or 2.

Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group and the like. Among these, an alkyl group having 1 to 3 carbon atoms is preferable, and an alkyl group having 1 or 2 carbon atoms is more preferable.

The reaction temperature is suitably set in a range from the melting point to the boiling point of the solvent used, and is usually about 0 to 100 ℃, and the content of the polyamic acid unit is maintained at a high level in order to prevent imidization of the solution of the polyamic acid obtained, preferably about 0 to 70 ℃, more preferably about 0 to 60 ℃, and still more preferably about 0 to 50 ℃.

The reaction time is not generally specified because it depends on the reaction temperature and the reactivity of the raw material, but is usually about 1 to 100 hours.

The reaction solution containing the target polyamic acid can be obtained by the method described above.

The weight average molecular weight of the polyamic acid is preferably 5,000 to 1,000,000, more preferably 10,000 to 500,000, and further preferably 15,000 to 200,000 from the viewpoint of handling property. In the present invention, the weight average molecular weight is an average molecular weight obtained by analyzing the weight average molecular weight in terms of standard polystyrene by Gel Permeation Chromatography (GPC).

In the present invention, the reaction solution is usually filtered, and the filtrate as it is, or a solution obtained by dilution or concentration can be used as the composition for forming a release layer of the present invention. In this way, not only can the contamination of impurities, which can cause deterioration of the adhesiveness, the peelability, and the like of the obtained peeling layer, be reduced, but also the composition for forming the peeling layer can be obtained efficiently. Further, the polyamic acid may be isolated from the reaction solution, and then dissolved in a solvent again to prepare a composition for forming a release layer. Examples of the solvent in this case include organic solvents used in the above-mentioned reaction.

The solvent used for the dilution is not particularly limited, and specific examples thereof include those similar to those of the reaction solvent of the above reaction. The solvent used for dilution may be used alone in 1 kind or in combination of 2 or more kinds. Among them, from the viewpoint of sufficiently dissolving the polyamic acid, N-dimethylformamide, N-dimethylacetamide, N-methyl-2-pyrrolidone, 1, 3-dimethyl-2-imidazolidinone, N-ethyl-2-pyrrolidone, and γ -butyrolactone are preferable, and N-methyl-2-pyrrolidone is more preferable.

The solvent that does not dissolve the polyamic acid alone can be mixed with the composition for forming a release layer of the present invention as long as the polyamic acid does not precipitate. In particular, solvents having a low surface tension such as ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 1-butoxy-2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol-1-monoethyl ether-2-acetate, dipropylene glycol, 2- (2-ethoxypropoxy) propanol, methyl lactate, ethyl lactate, n-propyl lactate, n-butyl lactate, and isoamyl lactate can be suitably mixed. It is known that the coating film uniformity is improved when the composition is applied to a substrate, and the composition is suitably used for forming a release layer of the present invention.

The concentration of the polyamic acid in the composition for forming a release layer of the present invention is suitably set in consideration of the thickness of the release layer to be produced, the viscosity of the composition, and the like, and is usually about 1 to 30 mass%, and preferably about 1 to 20 mass%. By setting the concentration to this level, a release layer having a thickness of about 0.05 to 5 μm can be obtained with good reproducibility. The concentration of the polyamic acid can be adjusted by adjusting the amounts of diamine and tetracarboxylic dianhydride used as raw materials of the polyamic acid, by diluting or concentrating the filtrate after filtering the reaction solution, or by adjusting the amounts of the isolated polyamic acid when dissolved in a solvent.

The viscosity of the composition for forming a release layer is suitably set in consideration of the thickness of the release layer to be produced, and in particular, when a film having a thickness of about 0.05 to 5 μm is to be obtained with good reproducibility, the viscosity is usually about 10 to 10,000 mPas, preferably about 20 to 5,000 mPas at 25 ℃. The viscosity can be measured using a commercially available viscometer for measuring the viscosity of a liquid, for example, under the condition of a composition temperature of 25 ℃ in accordance with the procedure described in JIS K7117-2. Preferably, a cone plate type (cone plate type) rotational viscometer can be used as the viscometer, preferably in a homotypic viscometer using 1 ° 34' × R24 as a standard cone spindle, at a temperature of 25 ℃ of the composition. An example of such a rotational viscometer is TVE-25L manufactured by Toyobo industries, Ltd.

The release layer forming composition according to the present invention may contain a component such as a crosslinking agent in addition to the polyamic acid and the organic solvent, for example, in order to improve the film strength.

By applying the release layer-forming composition of the present invention described above to a substrate and heating the obtained coating film to thermally imidize the polyamic acid, a release layer composed of a polyimide film having excellent adhesion to the substrate, and appropriate adhesion and peeling properties to a resin substrate can be obtained.

In the case where the release layer of the present invention is formed over a base, the release layer may be formed over a part of the surface of the base or may be formed over the entire surface of the base. As a method of forming a release layer on a part of the surface of the base, there is a method of forming a release layer only in a predetermined range on the surface of the base; and a method of forming a peeling layer in a pattern such as a dot pattern or a line/space pattern on the entire surface of the substrate. In the present invention, the substrate means a substrate to which the composition for forming a release layer according to the present invention is applied and which is used for the production of a flexible electronic device or the like.

Examples of the substrate (base material) include glass, plastics (polycarbonate, polymethacrylate, polystyrene, polyester, polyolefin, epoxy, melamine, triacetyl cellulose, ABS, AS, norbornene-based resin, etc.), metals (silicon wafer, etc.), wood, paper, slate, etc., and particularly, glass is preferable since the release layer obtained from the release layer-forming composition of the present invention has sufficient adhesion to the release layer. The surface of the substrate may be made of a single material, or may be made of 2 or more materials. As a method of forming the substrate surface with 2 or more kinds of materials, there is a method of forming a certain range of the substrate surface with a certain material and forming the remaining surface with another material; and a method in which a material existing in a pattern such as a dot pattern, a line pattern, and a space pattern on the entire surface of the substrate is present in another material.

The method of coating is not particularly limited, and examples thereof include a casting method, a spin coating method, a doctor blade coating method, a dip coating method, a roll coating method, a bar coating method, a die coating method, an inkjet method, and a printing method (relief printing, gravure printing, offset printing, screen printing, etc.).

The heating temperature for imidization is suitably determined in the range of usually 50 to 550 ℃, preferably 200 ℃ or higher, and preferably 500 ℃ or lower. By setting the heating temperature to such a temperature, the imidization reaction can be sufficiently performed while preventing the resultant film from becoming brittle. The heating time varies depending on the heating temperature, and therefore cannot be generally specified, but is usually 5 minutes to 5 hours. The imidization ratio may be in the range of 50 to 100%.

As a preferred example of the heating method in the present invention, the following method can be mentioned: after heating at 50 to 100 ℃ for 5 minutes to 2 hours, the heating temperature is raised in stages, and finally, the mixture is heated at a temperature of more than 375 ℃ to 450 ℃ for 30 minutes to 4 hours. Particularly preferably, the heating is carried out at 50 to 100 ℃ for 5 minutes to 2 hours, at a temperature of more than 100 ℃ to 375 ℃ or less for 5 minutes to 2 hours, and finally at a temperature of more than 375 ℃ to 450 ℃ or less for 30 minutes to 4 hours.

Examples of the heating device include a hot plate and an oven. The heating atmosphere may be air or an inert gas, or may be normal pressure or reduced pressure.

The thickness of the release layer is usually about 0.01 to 50 μm, preferably about 0.05 to 20 μm, more preferably about 0.05 to 5 μm from the viewpoint of productivity, and the thickness of the coating film before heating is adjusted to achieve a desired thickness.

The release layer described above has excellent adhesion to a substrate, particularly a glass substrate, appropriate adhesion to a resin substrate, and appropriate releasability. Therefore, the release layer according to the present invention can be suitably used in a manufacturing process of a flexible electronic device for: the resin substrate of the device is peeled from the base body together with a circuit and the like formed on the resin substrate without damaging the resin substrate.

An example of a method for manufacturing a flexible electronic device using the release layer of the present invention will be described below.

The composition for forming a peeling layer according to the present invention is used to form a peeling layer on a glass substrate by the above-described method. A resin solution for forming a resin substrate is applied to the release layer, and the coating film is heated, whereby a resin substrate fixed to a glass substrate is formed via the release layer according to the present invention. At this time, the release layer is entirely covered, and the resin substrate is formed to have an area larger than the area of the release layer. The resin substrate may be a resin substrate made of polyimide, which is a typical resin substrate for flexible electronic devices, and the resin solution used for forming the resin substrate may be a polyimide solution or a polyamic acid solution. The resin substrate can be formed by a conventional method.

Next, a desired circuit is formed on the resin substrate fixed to the base via the release layer according to the present invention, and then, for example, the resin substrate is cut along the release layer, and the resin substrate is peeled from the release layer together with the circuit, thereby separating the resin substrate and the base. At this time, a part of the base body may be cut together with the peeling layer.

On the other hand, in the manufacture of flexible displays, it has been reported that a polymer substrate can be suitably peeled from a glass carrier by using a laser lift-off method (LLO method) used in the manufacture of high-luminance LEDs, three-dimensional semiconductor packages, and the like (japanese patent laid-open publication No. 2013-147599). In the manufacture of a flexible display, it is necessary to provide a polymer substrate made of polyimide or the like on a glass carrier, then form a circuit or the like including an electrode or the like on the substrate, and finally peel the substrate from the glass carrier together with the circuit or the like. When the LLO method is used in this peeling step, that is, light having a wavelength of 308nm is irradiated to the glass support from the side opposite to the side on which the circuit or the like is formed, the light having the wavelength is transmitted through the glass support, and only the polymer (polyimide) in the vicinity of the glass support absorbs the light and evaporates (sublimes). As a result, it has been reported that the substrate can be selectively peeled from the glass carrier without affecting a circuit or the like provided on the substrate, which determines the performance of the display.

A desired circuit is formed on the resin substrate fixed to the base body via the peeling layer according to the present invention, and then, if the LLO method is employed, only the peeling layer absorbs the light and evaporates (sublimes). That is, the release layer is sacrificial (functions as a sacrificial layer), and the substrate can be selectively released from the glass carrier. The composition for forming a release layer of the present invention has a characteristic of sufficiently absorbing light having a specific wavelength (for example, 308nm) that is possible to apply the LLO method, and therefore can be used as a sacrificial layer in the LLO method.

Examples

The present invention will be described in more detail below by way of examples, comparative examples, examples and comparative examples, but the present invention is not limited to these examples. The abbreviations of the compounds used in the following examples and the methods for measuring the number average molecular weight and the weight average molecular weight are as follows.

< abbreviation of Compound >

p-PDA: p-phenylenediamine

m-PDA: m-phenylenediamine

DATP: 4,4' -diamino-p-terphenyl

DBA: 3, 5-diaminobenzoic acid

HAB: 3,3' -dihydroxybenzidine

DDE: 4,4' -oxydianiline

BAPB: 4,4' -bis (4-aminophenoxy) biphenyl

FAPB: 4,4' -bis (4-amino-2-trifluoromethylphenoxy) biphenyl

APAB: 5-amino-2- (4-aminophenyl) -1H-benzimidazole

APAB-E: 4-aminophenyl-4' -aminobenzoic acid ester

6 FAP: 2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane

TFMB: 2,2 '-bis (trifluoromethyl) biphenyl-4, 4' -diamine

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

TAHQ: p-phenylene bis (trimellitic acid monoester anhydride)

And (3) PMDA: pyromellitic dianhydride

BPTME: p-biphenylene bis (trimellitic acid monoester anhydride)

BPODA: 4,4'- (biphenyl-4, 4' -diylbis) diphthalic dianhydride

CF 3-BP-TMA: n, N ' - [2,2' -bis (trifluoromethyl) biphenyl-4, 4' -diyl ] bis (1, 3-dioxo-1, 3-dihydroisobenzofuran-5-carboxamide)

6 FDA: 4,4' - (Hexafluoroisopropylidene) diphthalic anhydrides

CBDA: 1,2,3, 4-cyclobutanetetracarboxylic dianhydride

IPBBT: n, N' -isophthaloyl bis (benzoxazoline-2-thione)

NMP: n-methyl-2-pyrrolidone

BCS: butyl cellosolve

< determination of weight average molecular weight and molecular weight distribution >

The weight average molecular weight (Mw) and the molecular weight distribution (Mw/Mn) of the polymer were measured using GPC apparatus (column: Ohapak SB803-HQ and Ohapak SB804-HQ, manufactured by Showa Denko K.K.; eluent: dimethylformamide/LiBr. H)₂O(29.6mM)/H₃PO₄(29.6mM)/THF (0.1 mass%); flow rate: 1.0 mL/min; column temperature: 40 ℃; mw: standard polystyrene equivalent) was performed (same in the following examples and comparative examples).

[1] Synthesis of polymers

Polyamic acid and polybenzoxazole precursors were synthesized by the following methods.

The polymer is not isolated from the obtained reaction solution containing the polymer, and the reaction solution is diluted as described later to prepare a composition for forming a resin substrate or a composition for forming a release layer.

Synthesis example S1 Synthesis of Polyamic acid S1

p-PDA20.261g (187mmol) and DATP12.206g (47mmol) were dissolved in NMP617.4g. The resulting solution was cooled to 15 ℃ and 50.112g (230mmol) of PMDA was added thereto, and the mixture was heated to 50 ℃ under a nitrogen atmosphere and reacted for 48 hours to obtain polyamic acid S1. Polyamic acid S1 had an Mw of 82,100 and an Mw/Mn of 2.7.

Synthesis example S2 Synthesis of Polyamic acid S2

p-PDA3.218g (30mmol) was dissolved in NMP88.2g. BPDA8.581g (29mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid S2. Polyamic acid S2 had an Mw of 107,300 and an Mw/Mn of 4.6.

Synthesis example S3 Synthesis of Polyamic acid S3

TFMB17.8g (56mmol), BAPB0.4g (1mmol) and p-PDA2.5g (23mmol) were dissolved in NMP430 g. 6FDA6.3g (14mmol) and CF3-BP-TMA42.8g (64mmol) were added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid S3. Polyamic acid S3 had an Mw of 38,700 and an Mw/Mn of 2.1.

Synthesis example S4 Synthesis of Polyamic acid S4

DDE30.6g (153mmol) was dissolved in NMP440 g. To the resulting solution, CBDA29.4g (150mmol) was added, and the reaction was carried out at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid S4. Polyamic acid S4 had an Mw of 29,800 and an Mw/Mn of 2.2.

Synthesis example L1 Synthesis of Polyamic acid L1

p-PDA2.054g (19mmol) was dissolved in NMP88 g. BPTME9.946g (19mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L1. Polyamic acid L1 had an Mw of 57,500 and an Mw/Mn of 3.0.

Synthesis example L2 Synthesis of Polyamic acid L2

p-PDA1.836g (17mmol) and DBA0.287g (1.9mmol) were dissolved in NMP88 g. BPTME9.878g (18mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L2. Polyamic acid L2 had an Mw of 65,100 and an Mw/Mn of 3.0.

Synthesis example L3 Synthesis of Polyamic acid L3

p-PDA1.367g (13mmol) and HAB1.172g (5.4mmol) were dissolved in NMP88 g. BPTME9.461g (18mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L3. Polyamic acid L3 had an Mw of 43,600 and an Mw/Mn of 2.6.

Synthesis example L4 Synthesis of Polyamic acid L4

DATP3.984g (15mmol) was dissolved in NMP88 g. To the resulting solution, BPTME8.016g (15mmol) was added and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L4. Polyamic acid L4 had an Mw of 42,600 and an Mw/Mn of 3.9.

Synthesis example L5 Synthesis of Polyamic acid L5

BAPB5.17g (14mmol) was dissolved in NMP88 g. BPTME6.83g (13mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L5. Polyamic acid L5 had an Mw of 52,100 and an Mw/Mn of 2.7.

Synthesis example L6 Synthesis of Polyamic acid L6

FAPB5.89g (12mmol) was dissolved in NMP88 g. BPTME6.11g (11mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L6. Polyamic acid L6 had an Mw of 87,700 and an Mw/Mn of 3.3.

Synthesis example L7 Synthesis of Polyamic acid L7

APAB3.60g (16mmol) was dissolved in NMP88 g. BPTME8.40g (16mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L7. Polyamic acid L7 had an Mw of 58,300 and an Mw/Mn of 2.8.

Synthesis example L8 Synthesis of Polyamic acid L8

DDE2.322g (12mmol) was dissolved in NMP35.2g. To the resulting solution, PMDA2.478g (11mmol) was added, and the reaction was carried out at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L8. Polyamic acid L8 had an Mw of 22,600 and an Mw/Mn of 2.1.

Synthesis example L9 Synthesis of Polyamic acid L9

DATP1.762g (7mmol) was dissolved in NMP35.2g. TAHQ3.038g (7mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L9. Polyamic acid L9 had an Mw of 61,300 and an Mw/Mn of 3.3.

Synthesis example L10 Synthesis of Polyamic acid L10

P-PDA0.899g (8mmol) was dissolved in NMP35.2g. BPODA3.900g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L10. Polyamic acid L10 had an Mw of 17,300 and an Mw/Mn of 2.4.

Synthesis example L11 Synthesis of Polyamic acid L11

DATP1.713g (7mmol) was dissolved in NMP35.2g. BPODA3.086g (6mmol) was added to the resulting solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L11. Polyamic acid L11 had an Mw of 27,000 and an Mw/Mn of 2.4.

Synthesis example L12 Synthesis of Polyamic acid L12

p-PDA0.931g (9mmol) was dissolved in NMP35.2g. TAHQ3.868g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L12. Polyamic acid L12 had an Mw of 45,000 and an Mw/Mn of 2.7.

Synthesis example L13 Synthesis of Polyamic acid L13

p-PDA0.839g (8mmol) and m-PDA0.093g (1mmol) were dissolved in NMP35.2g. TAHQ3.868g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L13. Polyamic acid L13 had an Mw of 39,100 and an Mw/Mn of 2.6.

Synthesis example L14 Synthesis of Polyamic acid L14

p-PDA0.652g (6mmol) and m-PDA0.280g (3mmol) were dissolved in NMP35.2g. TAHQ3.868g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L14. Polyamic acid L14 had an Mw of 42,700 and an Mw/Mn of 2.6.

Synthesis example L15 Synthesis of Polyamic acid L15

m-PDA0.931g (9mmol) was dissolved in NMP35.2g. TAHQ3.868g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L15. Polyamic acid L15 had an Mw of 36,100 and an Mw/Mn of 2.5.

< Synthesis example L16 Synthesis of Polyamic acid L16

p-PDA0.816g (8mmol) and DATP0.218g (1mmol) were dissolved in NMP35.2g. TAHQ3.765g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L16. Polyamic acid L16 had an Mw of 43,800 and an Mw/Mn of 2.5.

Synthesis example L17 Synthesis of Polyamic acid L17

p-PDA0.603g (6mmol) and DATP0.622g (2mmol) were dissolved in NMP35.2g. TAHQ3.575g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L17. Polyamic acid L17 had an Mw of 46,000 and an Mw/Mn of 2.6.

Synthesis example L18 Synthesis of Polyamic acid L18

p-PDA0.832g (8mmol) and DBA0.130g (1mmol) were dissolved in NMP35.2g. TAHQ3.838g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L18. Polyamic acid L18 had an Mw of 57,000 and an Mw/Mn of 3.0.

Synthesis example L19 Synthesis of Polyamic acid L19

p-PDA0.822g (8mmol) and HAB0.183g (1mmol) were dissolved in NMP35.2g. TAHQ3.794g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L19. Polyamic acid L19 had an Mw of 54,200 and an Mw/Mn of 2.7.

Synthesis example L20 Synthesis of Polyamic acid L20

p-PDA0.616g (6mmol) and HAB0.528g (2mmol) were dissolved in NMP35.2g. TAHQ3.655g (8mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L20. Polyamic acid L20 had an Mw of 55,900 and an Mw/Mn of 2.6.

Synthesis example L21 Synthesis of Polyamic acid L21

APAB-E1.239g (5mmol) was dissolved in NMP17.6g. To the resulting solution, 1.160g (5mmol) of PMDA was added, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L21. Polyamic acid L21 had an Mw of 20,900 and an Mw/Mn of 2.1.

Synthesis example L22 Synthesis of Polyamic acid L22

APAB-E1.060g (5mmol) was dissolved in NMP17.6 g. BPDA1.339g (5mmol) was added to the obtained solution, and the mixture was reacted at 23 ℃ for 24 hours under a nitrogen atmosphere to obtain polyamic acid L22. Polyamic acid L22 had an Mw of 26,600 and an Mw/Mn of 2.3.

Comparative Synthesis example 1 Synthesis of polybenzoxazole precursor B1

6FAP5.49g (0.015mol) was dissolved in NMP27 g. To the resulting solution was added IPBBT6.48g (0.015mol), and the mixture was reacted at 23 ℃ for 3 hours under a nitrogen atmosphere. Then, the solution was poured into 300g of pure water, stirred for 24 hours, and then the precipitate was filtered. Then, drying was performed under reduced pressure to obtain polybenzoxazole precursor B1. The Mw of the polybenzoxazole precursor B1 was 2,1000 and the Mw/Mn was 3.9.

[2] Preparation of composition for Forming resin substrate

The reaction liquids obtained in synthesis examples S1 to S4 were used as they were as resin substrate-forming compositions W, X, Y and Z, respectively.

[3] Preparation of composition for Forming Release layer

[ example 1-1]

BCS was added to the reaction solution obtained in synthesis example L1, and the mixture was diluted with NMP so that the polymer concentration became 5 mass% and the BCS became 20 mass%, to obtain a composition for forming a release layer.

Examples 1-2 to 1-22

A release layer-forming composition was obtained in the same manner as in example 1-1, except that the reaction liquids obtained in Synthesis examples L2 to L22 were used instead of the reaction liquid obtained in Synthesis example L1.

Comparative example 1

The reaction solution obtained in comparative synthesis example 1 was diluted with NMP so that the polymer concentration became 5 mass%, to obtain a composition.

[4] Formation of Release layer and evaluation thereof

[ example 2-1]

The composition for forming a peeling layer obtained in example 1-1 was applied onto a 100mm × 100mm glass substrate (hereinafter the same shall apply) as a glass substrate by using a spin coater (conditions: about 30 seconds at 3000 rpm).

Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, then at 300 ℃ for 30 minutes using an oven, the heating temperature was raised (10 ℃/minute) to 400 ℃, and further at 400 ℃ for 30 minutes, and a release layer having a thickness of about 0.1 μm was formed on the glass substrate. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven.

[ examples 2-2 to 2-22]

A release layer was formed in the same manner as in example 2-1, except that the release layer-forming compositions obtained in examples 1-2 to 1-22 were used instead of the release layer-forming composition obtained in example 1-1.

[ examples 2 to 23]

The composition for forming a release layer obtained in examples 1 to 12 was applied on a glass substrate of 100mm × 100mm using a spin coater (condition: about 30 seconds at a rotation speed of 3000 rpm).

Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, then at 140 ℃ for 30 minutes using an oven, the heating temperature was raised (2 ℃/min) to 250 ℃, and further at 250 ℃ for 60 minutes, and a release layer having a thickness of about 0.1 μm was formed on the glass substrate. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven.

[ examples 2 to 24]

The composition for forming a peeling layer obtained in examples 1 to 8 was applied on a glass substrate of 100mm × 100mm as a glass base by using a spin coater (condition: about 30 seconds at a rotation speed of 3000 rpm).

Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, then heated at 300 ℃ for 30 minutes in a nitrogen atmosphere using an oven, the heating temperature was raised (10 ℃/minute) to 400 ℃, further heated at 400 ℃ for 60 minutes, and finally heated at 500 ℃ for 10 minutes, and a release layer having a thickness of about 0.1 μm was formed on the glass substrate. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven.

[ examples 2 to 25]

A resin film was formed in the same manner as in examples 2 to 24, except that the composition obtained in examples 1 to 12 was used in place of the release layer-forming composition obtained in examples 1 to 8.

Comparative example 2

A resin film was formed in the same manner as in example 2-1, except that the composition obtained in comparative example 1 was used in place of the composition for forming a release layer obtained in example 1-1.

[5] Evaluation of peelability

Examples 3-1 to 3-47 and comparative example 3

The releasability between the release layer obtained in examples 2-1 to 2-25 and the glass substrate and the releasability between the release layer (resin film) and the resin substrate were confirmed. As the resin substrate, a resin substrate made of polyimide was used.

First, 100 mesh cuts were performed by performing the cross cutting (1mm interval in vertical and horizontal directions, the same applies hereinafter) of the release layer on the glass substrate with a release layer obtained in examples 2-1 to 2-25 and the cross cutting of the resin substrate and the release layer on the resin substrate/the glass substrate with a release layer. That is, by this cross cutting, 100 meshes of 1mm squares are formed.

Then, a pressure-sensitive adhesive tape was applied to the 100 mesh cut portions, and the tape was peeled off, and the degree of peeling was evaluated based on the following criteria (5B to 0B, B, A, AA) (examples 3-1 to 3-47). In addition, the same test was performed using the glass substrate with a resin thin film obtained in comparative example 2 according to the above-described method (comparative example 3). The results are shown in table 1. The evaluation criteria for peelability in table 1 are as follows.

5B: 0% Peel off (No Peel off)

4B: peeling of less than 5%

3B: 5 to less than 15% peeling

2B: 15 to less than 35% peeling

1B: 35 to less than 65% peeling

0B: 65% to less than 80% peeling

B: 80% to less than 95% peeling

A: 95% to less than 100% peeling

AA: 100% peel (Total peel)

The resin substrates of examples 3-1 to 3-41, 3-44 to 3-47 and comparative example 3 were formed by the following method.

Either of the compositions W and X for forming a resin substrate was coated on a release layer (resin film) on a glass substrate using a bar coater (gap: 250 μm). Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, and then heated at 140 ℃ for 30 minutes using an oven, the heating temperature was raised to 210 ℃ for 30 minutes at 210 ℃, the heating temperature was raised to 300 ℃ for 30 minutes at 300 ℃, the heating temperature was raised to 400 ℃ for 60 minutes at 400 ℃, and a polyimide substrate having a thickness of about 20 μm was formed on the release layer. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven.

The resin substrates of examples 3-42 to 3-43 were formed by the following method.

Either of the compositions Y and Z for forming a resin substrate was applied to the release layer on the glass substrate using a bar coater (gap: 50 μm). Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, and then at 140 ℃ for 30 minutes using an oven, the heating temperature was raised (2 ℃/min) to 250 ℃ and at 250 ℃ for 60 minutes, and a polyimide substrate having a thickness of about 0.8 μm was formed on the release layer. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven.

[ Table 1]

[ Table 2]

As shown in tables 1 and 2, the release layer of the example was found to have excellent adhesion to the glass substrate and excellent releasability from the resin substrate. On the other hand, the release layer of the comparative example did not peel from the resin substrate and the glass substrate, and did not function as a release layer.

[6] Evaluation of transmittance

[ example 4]

The composition for forming a peeling layer obtained in examples 2 to 8 was applied to a 100mm × 100mm glass substrate (the same applies below) as a glass substrate by using a spin coater (conditions: about 30 seconds at 800 rpm).

Then, the obtained coating film was heated at 80 ℃ for 10 minutes using a hot plate, then at 300 ℃ for 30 minutes using an oven, the heating temperature was raised (10 ℃/minute) to 400 ℃, and further at 400 ℃ for 30 minutes, and a release layer having a thickness of about 0.4 μm was formed on the glass substrate. During the temperature rise, the substrate with the film was not taken out of the oven and heated in the oven. The transmittance of the obtained film was measured by using an ultraviolet-visible spectrophotometer (SIMADSU UV-2550, manufactured by Shimadzu corporation).

The results are shown in fig. 1. The transmittance of the obtained film was 1% or less at a wavelength of 308nm, and it showed a transmittance usable as a sacrificial layer.