1. The cover plate for PCB drilling is characterized by comprising a carrier layer and a high polymer material layer arranged on the surface of the carrier layer; the carrier layer is a cold punching plate or a phenolic paper cover plate; the polymer material layer comprises the following components in parts by weight: 50-85 parts of epoxy resin, 5-10 parts of curing agent, 3-5 parts of filler, 4-8 parts of pigment and 0.5-2.5 parts of auxiliary agent.

2. The cover plate for drilling the PCB according to claim 1, wherein the epoxy resin comprises the following components in parts by weight: 40-70 parts of bisphenol A type epoxy resin and 20-50 parts of polypropylene glycol diglycidyl ether.

3. The PCB drilling cover plate according to claim 1, wherein the curing agent is an organic polyamine compound.

4. The cover plate for drilling the PCB according to claim 1, wherein the auxiliary agent comprises the following components in parts by weight: 0.2-1 part of defoaming agent, 0.2-1 part of flatting agent and 0.2-0.8 part of dispersing agent.

5. The cover plate for drilling PCB according to claim 1, wherein the thickness of the polymer material layer is 30-100 μm.

6. The PCB drilling cover plate of claim 1, wherein the carrier layer has a thickness of 0.05-0.2 mm.

7. A method for preparing a cover plate for PCB drilling according to any one of claims 1-6, comprising:

uniformly mixing 50-85 parts by weight of epoxy resin, 3-5 parts by weight of filler, 4-8 parts by weight of pigment and 0.5-2.5 parts by weight of auxiliary agent to prepare epoxy resin coating;

uniformly mixing 0-20 parts by weight of diluent, 5-10 parts by weight of curing agent and 60-90 parts by weight of epoxy resin coating to prepare diluted epoxy resin coating;

coating the diluted epoxy resin paint on the surface of the carrier layer;

and drying the carrier layer coated with the diluted epoxy resin coating to form the high polymer material layer on the surface of the carrier layer by the diluted epoxy resin coating, so as to prepare the PCB drilling cover plate.

8. The method of claim 7, wherein the step of applying the diluted epoxy resin paint to the surface of the carrier layer comprises:

and coating the diluted epoxy resin coating on the surface of the carrier layer by a roll coater at a roll coating speed of 18-30 m/min.

9. The method of claim 7, wherein the step of drying the carrier layer coated with the diluted epoxy resin paint comprises:

the carrier layer coated with the diluted epoxy coating was subjected to a drying process at 150-235 deg.c.

10. Use of a cover plate for PCB drilling according to any of claims 1-6, comprising: and using the PCB drilling cover plate for drilling the PCB.

Background

A cover plate (short for cover plate) for drilling a Printed Circuit Board (PCB) is an auxiliary material which is placed on the surface of a PCB to be processed when the PCB is mechanically drilled so as to meet the requirements of a processing process. Because a large number of cover plates are required in the mechanical drilling processing production of the PCB, and along with the rapid development of the PCB drilling technology in recent years, the cover plate industry becomes an important component with a considerable scale in the PCB raw and auxiliary material industry.

Depending on the material, the cover plates are generally classified on the market into the following categories: phenolic paper cover plates (including phenolic paper cover plates and cold punching plates), common aluminum sheets (namely aluminum foil cover plates) and epoxy glass cloth cover plates. The phenolic paper cover plate and the cold punching plate are mainly used for drilling holes in an FPC (Flexible Printed Circuit); the common aluminum sheet is made of alloy aluminum foil and is used for drilling common and fine circuit boards; the epoxy glass fiber cloth cover plate is composed of epoxy resin and glass fiber cloth, and the amount of the epoxy glass fiber cloth cover plate on the market is very small at present.

With continuous forward progress and development of society, the requirement on high precision of electronic products is higher and higher, and the high precision development of electronic products directly puts forward the high precision requirement to circuit board processing, also makes the drilling hole site precision and the downthehole quality requirement on PCB drilling higher and higher simultaneously. Especially, the drilling requirements of micro-holes with the diameters of 0.075mm and 0.10mm have appeared on a high-end FPC, and the quality problems that the defective rate of broken pins and deviated holes is high, the abrasion of the tool face of a drill bit is serious, the hole wall quality cannot meet the requirements of customers and the like can appear when the existing cover plate is used for drilling. Therefore, a new cover plate is urgently needed to meet the quality requirement of drilling holes with micro apertures.

Disclosure of Invention

In view of the above problems, the present application is proposed to provide a cover plate for PCB drilling, a method for preparing the same and applications thereof, which overcome or at least partially solve the problems, including:

a PCB drilling cover plate comprises a carrier layer and a high polymer material layer arranged on the surface of the carrier layer; the carrier layer is a cold punching plate or a phenolic paper cover plate; the polymer material layer comprises the following components in parts by weight: 50-85 parts of epoxy resin, 5-10 parts of curing agent, 3-5 parts of filler, 4-8 parts of pigment and 0.5-2.5 parts of auxiliary agent.

Preferably, the epoxy resin comprises the following components in parts by weight: 40-70 parts of bisphenol A type epoxy resin and 20-50 parts of polypropylene glycol diglycidyl ether.

Preferably, the curing agent is an organic polyamine compound.

Preferably, the auxiliary agent comprises the following components in parts by weight: 0.2-1 part of defoaming agent, 0.2-1 part of flatting agent and 0.2-0.8 part of dispersing agent.

Preferably, the thickness of the polymer material layer is 30-100 μm.

Preferably, the support layer has a thickness of 0.05-0.2 mm.

A preparation method of the cover plate for PCB drilling comprises the following steps:

uniformly mixing 50-85 parts by weight of epoxy resin, 3-5 parts by weight of filler, 4-8 parts by weight of pigment and 0.5-2.5 parts by weight of auxiliary agent to prepare epoxy resin coating;

uniformly mixing 0-20 parts by weight of diluent, 5-10 parts by weight of curing agent and 60-90 parts by weight of epoxy resin coating to prepare diluted epoxy resin coating;

coating the diluted epoxy resin paint on the surface of the carrier layer;

and drying the carrier layer coated with the diluted epoxy resin coating to form the high polymer material layer on the surface of the carrier layer by the diluted epoxy resin coating, so as to prepare the PCB drilling cover plate.

Preferably, the step of applying the diluted epoxy resin paint on the surface of the carrier layer includes:

and coating the diluted epoxy resin coating on the surface of the carrier layer by a roll coater at a roll coating speed of 18-30 m/min.

Preferably, the step of drying the carrier layer coated with the diluted epoxy resin paint includes:

the carrier layer coated with the diluted epoxy coating was subjected to a drying process at 150-235 deg.c.

Use of a cover plate for PCB drilling as described above, comprising: and using the PCB drilling cover plate for drilling the PCB.

The application has the following advantages:

in the embodiment of the application, the carrier layer and the polymer material layer arranged on the surface of the carrier layer are used for forming the carrier layer; the carrier layer is a cold punching plate or a phenolic paper cover plate; the polymer material layer comprises the following components in parts by weight: 50-85 parts of epoxy resin, 5-10 parts of curing agent, 3-5 parts of filler, 4-8 parts of pigment and 0.5-2.5 parts of auxiliary agent, wherein the high polymer material layer has low hardness, so that the deviation of the drill bit during drilling can be effectively avoided, and the hole site precision of the drill bit is improved; meanwhile, the Tg (Glass Transition Temperature) of the polymer material layer is low, so that the heat of the drill bit can be absorbed, the Temperature of the drill bit is reduced, and the abrasion and the loss of the drill bit are reduced, so that the service life of the drill bit is effectively prolonged, the drill bit has a good cutting effect on the FPC board after the Temperature of the drill bit is reduced, the surface of the hole is smooth, the wall of the hole is smooth, and the yield of products is effectively improved; in addition, the softened polymer material layer can effectively clean the dust attached to the drill bit, and is favorable for rapid chip removal.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings needed to be used in the description of the present application will be briefly introduced below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor.

Fig. 1 is a schematic structural diagram of a cover plate for PCB drilling according to an embodiment of the present disclosure;

fig. 2 is a flowchart illustrating steps of a method for manufacturing a cover plate for PCB drilling according to an embodiment of the present disclosure;

fig. 3 is a flowchart illustrating steps of an application of a PCB drilling cover plate according to an embodiment of the present application.

The reference numbers in the drawings of the specification are as follows:

1. a carrier layer; 2. a polymer material layer.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, the present application is described in further detail with reference to the accompanying drawings and the detailed description. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, a cover plate for PCB drilling provided by an embodiment of the present application is shown, including a carrier layer 1 and a polymer material layer 2 disposed on a surface of the carrier layer 1; the carrier layer 1 is a cold punching plate or a phenolic paper cover plate; the polymer material layer 2 comprises the following components in parts by weight: 50-85 parts of epoxy resin, 5-10 parts of curing agent, 3-5 parts of filler, 4-8 parts of pigment and 0.5-2.5 parts of auxiliary agent.

The high polymer material layer 2 is a net-shaped three-dimensional polymer formed by the crosslinking reaction of the components, the hardness of the high polymer material layer 2 is 1-2H (Mitsubishi hardness Pencil test method), and the Tg is 250 ℃.

In the embodiment of the application, the carrier layer 1 and the high polymer material layer 2 arranged on the surface of the carrier layer 1 are used for preparing the high polymer material; the carrier layer 1 is a cold punching plate or a phenolic paper cover plate; the polymer material layer 2 comprises the following components in parts by weight: 50-85 parts of epoxy resin, 5-10 parts of curing agent, 3-5 parts of filler, 4-8 parts of pigment and 0.5-2.5 parts of auxiliary agent, wherein the high polymer material layer 2 has low hardness, so that the deviation of the drill bit during drilling can be effectively avoided, and the hole site precision of the drill bit is improved; meanwhile, the Tg of the polymer material layer 2 is low, so that the heat of the drill bit can be absorbed, the temperature of the drill bit is reduced, and the abrasion and the loss of the drill bit are reduced, so that the service life of the drill bit is effectively prolonged, the drill bit has a good cutting effect on the FPC board after the temperature of the drill bit is reduced, the surface of a hole is flat, the wall of the hole is smooth, and the yield of products is effectively improved; in addition, the softened polymer material layer 2 can effectively clean the dust attached to the drill bit, and is favorable for rapid chip removal.

Hereinafter, a PCB drilling cover plate in the present exemplary embodiment will be further described.

In this embodiment, the epoxy resin comprises the following components in parts by weight: 40-70 parts of bisphenol A type epoxy resin and 20-50 parts of polypropylene glycol diglycidyl ether.

As an example, the bisphenol A type epoxy resin may be at least one of E-44 epoxy resin (E-44 for short, epoxy value is 0.41-0.47mo1/100g), E-51 epoxy resin (E-51 for short, epoxy value is 0.48-0.54mo1/100g), E-55 epoxy resin (E-55 for short, epoxy value is 0.55-0.56mo1/100g), and is preferably an epoxy resin with a trade name of NPEL 128. The bisphenol A type epoxy resin is prepared by polycondensation of bisphenol A and epichlorohydrin under the action of an alkaline catalyst, can form a cured product with excellent performance with a plurality of curing agents, catalysts and additives, basically does not generate small-molecule volatile matters during curing, and has high bonding strength, high corrosion resistance and electrical performance, and certain toughness and heat resistance. The polypropylene glycol diglycidyl ether is preferably polypropylene glycol diglycidyl ether available under the trade name DER 732. The polypropylene glycol diglycidyl ether is prepared by reacting epichlorohydrin with polypropylene glycol, is an epoxy resin with flexibility, low viscosity and light color, can reduce the viscosity of the bisphenol A epoxy resin, and endows a system with excellent flexibility, extensibility and impact resistance.

In this embodiment, the curing agent is an organic polyamine compound. The curing agent can react with epoxy resin to form a reticular three-dimensional polymer, and the composite material aggregate is enveloped in a reticular body, so that the linear resin becomes a tough body-type solid.

In this embodiment, the filler is at least one of silicate and calcium carbonate, and preferably calcium carbonate. Calcium carbonate is a non-toxic, tasteless, non-irritating white powder that is neutral, substantially insoluble in water, and soluble in acid.

In the embodiment, the auxiliary agent comprises the following components in parts by weight: 0.5-1 part of defoaming agent, 0.3-0.8 part of flatting agent and 0.3-0.8 part of dispersing agent. As an example, the defoamer may be a foam breaking polymer and polysiloxane solution, preferably a defoamer under the trade name BYK 530; the defoaming agent can effectively prevent bubbles from occurring in a system in the production and application processes. The leveling agent can be polyether modified organic siloxane, and is preferably a leveling agent with the trade name of BYK 354; the leveling agent can improve the leveling and gloss of a system, generate a long-wave effect and prevent shrinkage cavity. The dispersant may be fumed silica, preferably fumed silica under the trade name R972; the dispersant can uniformly disperse solid and liquid particles in a system, and can prevent the particles from settling and coagulating to form a stable suspension.

In this embodiment, the thickness of the polymer material layer 2 is 20 to 100 μm, preferably 30 μm and 50 μm.

In the present embodiment, the thickness of the carrier layer 1 is 0.1 to 0.2mm, preferably 0.12mm and 0.16 mm.

In this embodiment, the polymer material layer 2 has a hardness of 1 to 2H, preferably 1.2H, 1.5H, and 1.8H.

In this embodiment, the Tg of the polymer material layer 2 is 250 ℃.

Referring to fig. 2, there is shown a method for preparing a cover plate for PCB drilling according to any one of the above embodiments, including:

s210, uniformly mixing 50-85 parts by weight of epoxy resin, 3-5 parts by weight of filler, 4-8 parts by weight of pigment and 0.5-2.5 parts by weight of auxiliary agent to prepare epoxy resin paint;

s220, uniformly mixing 0-20 parts by weight of the diluent, 5-10 parts by weight of the curing agent and 50-90 parts by weight of the epoxy resin coating to prepare a diluted epoxy resin coating;

s230, coating the diluted epoxy resin paint on the surface of the carrier layer 1;

s240, drying the carrier layer 1 coated with the diluted epoxy resin coating, so that the diluted epoxy resin coating forms the high polymer material layer 2 on the surface of the carrier layer 1, and thus the PCB drilling cover plate is obtained.

In an embodiment of the present application, the specific process of "uniformly mixing 50 to 85 parts by weight of epoxy resin, 3 to 5 parts by weight of filler, 4 to 8 parts by weight of pigment and 0.5 to 2.5 parts by weight of auxiliary agent to obtain epoxy resin coating" in step S210 can be further described with reference to the following description.

And (5) cleaning the container. Specifically, the container is washed with ethyl acetate or ethanol.

And sequentially adding 40-70 parts by weight of the bisphenol A epoxy resin, 20-50 parts by weight of the polypropylene glycol diglycidyl ether, 0.3-0.8 part by weight of the defoaming agent and 0.2-0.8 part by weight of the leveling agent into the container, and uniformly dispersing for 5 min.

3-5 parts by weight of the filler, 0.3-0.8 part by weight of the dispersant and 4-8 parts by weight of the pigment are sequentially added into the container while stirring, and are dispersed for 5min at a constant speed.

Dispersing the above materials at high speed for 15-20 min.

And cleaning the grinding equipment. Specifically, the milling apparatus is cleaned with ethyl acetate or ethanol.

And grinding the materials by adopting the grinding equipment. Specifically, the material is repeatedly ground for 8 times by the grinding equipment, the fineness of the material is irregularly detected by a fineness device, and the fineness is determined to be qualified (namely the scraping fineness is below 15 mu m).

And filtering the materials to obtain the epoxy resin coating. Specifically, the materials are filtered by adopting 300-mesh filter cloth.

The viscosity of the epoxy coating was tested. Specifically, the viscosity of the diluted epoxy resin coating is tested by using a four-coating viscometer for 40-45 s.

The epoxy coating was packaged as required and the final weight was recorded. Specifically, the epoxy resin coating is filled into a barrel No. one and the barrel cover is sealed to prevent transport leakage.

In an embodiment of the present application, the specific process of "uniformly mixing 0 to 20 parts by weight of the diluent, 5 to 10 parts by weight of the curing agent and 60 to 90 parts by weight of the epoxy resin coating to obtain a diluted epoxy resin coating" in step S220 can be further described with reference to the following description.

And (5) cleaning the container. Specifically, the container is washed with ethyl acetate or ethanol.

And sequentially adding 60-90 parts by weight of the epoxy resin coating, 0-20 parts by weight of the diluent and 5-10 parts by weight of the curing agent into the container, and dispersing at a constant speed for 20-30min to obtain the diluted epoxy resin coating. The diluent is an inactive diluent, does not participate in the reaction between the epoxy resin and the curing agent, and volatilizes along with the curing reaction; the diluent can reduce the viscosity of the epoxy resin, improve the process performance of the epoxy resin and facilitate the construction of the epoxy resin coating; the curing agent may be a blocked curing agent.

The viscosity of the diluted epoxy resin coating was tested. Specifically, the viscosity of the diluted epoxy resin coating was measured using a four-bar viscometer for a test time of 40-45 s.

In an embodiment of the present application, before the step S120 of uniformly mixing 0 to 20 parts by weight of the diluent, 5 to 10 parts by weight of the curing agent, and 60 to 90 parts by weight of the epoxy resin coating to obtain the diluted epoxy resin coating, the method further includes:

and (5) cleaning the container. Specifically, the container is washed with ethyl acetate or ethanol.

And sequentially adding 60 parts by weight of the ethylene glycol ethyl ether and 40 parts by weight of the acetone into the container, and uniformly dispersing for 5min to obtain the diluent.

Filtering the diluent and the curing agent. Specifically, the diluent and the curing agent are filtered by using a 300-mesh filter cloth.

The diluent was packaged as required and the final weight was recorded. Specifically, the diluent is loaded into a second barrel and the barrel lid is sealed to prevent shipping leakage.

In an embodiment of the present application, the specific process of "applying the diluted epoxy resin coating on the surface of the carrier layer 1" in step S230 can be further described with reference to the following description.

And cleaning the roller coater. Specifically, the roll coater was cleaned with a dust-free cloth.

And adjusting the roll coating speed of the roll coating machine. Specifically, the roll coating speed of the roll coating machine is adjusted to 18-30 m/min.

And coating the diluted epoxy resin paint on the surface of the carrier layer 1 by using the roll coating machine.

In an embodiment of the present application, a specific process of "performing a drying process on the carrier layer 1 coated with the diluted epoxy resin coating so that the diluted epoxy resin coating forms the polymer material layer 2 on the surface of the carrier layer 1 to obtain the PCB drilling cover plate" in step S240 may be further described with reference to the following description.

And cleaning and drying the machine. Specifically, the dryer is cleaned with a dust-free cloth.

And adjusting the baking temperature of the dryer. Specifically, the baking temperature of the dryer is adjusted to 150-.

And drying the carrier layer 1 coated with the diluted epoxy resin coating by using the dryer, so that the diluted epoxy resin coating forms the high polymer material layer 2 on the surface of the carrier layer 1, and thus the PCB drilling cover plate is obtained. Specifically, the surface of the carrier layer 1 coated with the diluted epoxy resin coating faces upwards, and drying treatment is carried out at the temperature of 150-235 ℃; or; the carrier layer 1 is dried at 220-230 ℃ with the surface coated with the diluted epoxy resin paint facing downwards.

And performing film thickness and surface drying tests on the PCB drilling cover plate. Specifically, the first PCB drilling cover plate after film formation was subjected to film thickness and surface drying tests, and thereafter tested every ten minutes and recorded.

Referring to fig. 3, there is shown an application of a cover plate for PCB drilling according to an embodiment of the present application, including:

s310, the PCB drilling cover plate is used for drilling of the PCB.

In an embodiment of the present application, a specific process of "using the PCB drilling cover plate for PCB drilling" in step S310 may be further described in conjunction with the following description.

The PCB to be drilled and the PCB drilling cover plate are sequentially placed on the machine table from bottom to top, so that the carrier layer 1 faces the PCB, and the high polymer material layer 2 faces the drill bit. Specifically, the backing plate can be a phenolic paper backing plate, and has the characteristics of high flatness, high temperature resistance, deformation resistance and the like; the PCB is an FPC (flexible printed circuit) or a rigid-flex board or a PCB with the thickness less than or equal to 0.6 mm; the drill bit is a UC type drill bit.

And controlling the drill bit to drill downwards from the upper part of the cover plate for PCB drilling. Specifically, the drill is controlled to drill downwards from the upper part of the PCB drilling cover plate at the rotating speed of 100KRMP, the feed speed of 2.7m/min and the withdrawal speed of 22.05 m/min.

And controlling the drill bit to stop drilling after the drill bit sequentially drills through the cover plate for drilling the PCB and contacts with the base plate.

While preferred embodiments of the present application have been described, additional variations and modifications of these embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the true scope of the embodiments of the application.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or terminal that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or terminal. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or terminal that comprises the element.

The above detailed description is given to the cover plate for PCB drilling and the preparation method and application thereof, and the specific examples are applied herein to explain the principle and the implementation of the present application, and the description of the above examples is only used to help understand the method and the core idea of the present application; meanwhile, for a person skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.