Resin composition and base plate for drilling PCB (Printed Circuit Board) by adopting same

Abstract

The invention discloses a resin composition and a base plate for PCB drilling using the same, the resin composition comprises the following components by weight: 20-40 parts of main resin, 20-30 parts of water-soluble starch, 4-18 parts of a pigment, 10-80 parts of a filler, 0.2-1 part of an auxiliary agent, and 0.5-1 part of a leveling agent, and the curing temperature of the resin composition is 5-40 DEG C. According to the base plate, the resin composition is adopted as a coating layer, the advantages of high hardness, high binding power and capability of being cured at normal temperature are utilized, the prepared base plate can remarkably inhibit burrs during drilling, and the base plate is simple and convenient in production process, low in energy consumption and capable of being widely applied.

Description

Technical Field

[0001] The invention relates to the field of printed circuit board drilling processing, in particular to a resin composition and a PCB drilling backing plate using the composition. Background Art

[0002] During the drilling process, the copper foil on the surface and bottom of the circuit board may produce flowers and burrs due to the friction and extrusion of the drill bit. The use of the pad can effectively prevent this phenomenon, make the drilling surface smooth, and thus improve the quality of the PCB printed circuit board. Due to the characteristics of flat board surface, high hardness, wear resistance and scratch resistance, the UV pad can accurately position the drill bit during the PCB drilling process, protect the PCB board from damage during the drilling process, reduce the burrs and flash generated during the drilling process, improve the drilling quality, and resist the wear of the drill bit and extend the service life of the drill bit. Therefore, it is currently a commonly used pad for PCB drilling. However, since the coating applied to the wood fiber board during the production process of the UV pad needs to be photocured to achieve a hardness of H or above, and the UV coating contains organic solvents, it is easy to volatilize light components that are harmful to the human body during the photocuring and production process. In addition, during the photocuring process, due to the high temperature, the thin plate is also prone to warping problems. For example, uneven coating and curing can easily form a rough granular feeling on the surface of the plate, affecting the drilling performance, especially having a great impact on suppressing flash. UV coatings also require the use of equipment with high energy consumption, such as mercury lamps and LED energy lamps, during curing, and the production process is complicated.

[0003] Therefore, it is urgent to find a product with matching performance, simple production process and lower energy consumption. Summary of the invention

[0004] In view of the defects in the prior art, the present invention provides a resin composition and a PCB drilling pad using the composition.

[0005] The invention provides a resin composition, which comprises the following components in parts by weight: 20-40 parts of a main resin, such as 20, 25, 30, 35, and 40 parts; 20-30 parts of a water-soluble starch, such as 20, 22, 24, 26, 28, and 30 parts; 4-18 parts of a pigment, such as 4, 6, 8, 10, 12, 14, 16, and 18 parts; 10-80 parts of a filler, such as 10, 20, 30, 40, 50, 60, 70, and 80 parts; 0.2-1 part of an auxiliary agent, such as 0.2, 0.4, 0.6, 0.8, and 1 part; and 0.5-1 part of a leveling agent, such as 0.5, 0.6, 0.7, 0.8, 0.9, and 1 part.

[0006] The curing temperature of the resin composition is 5-40°C.

[0007] Adding water-soluble starch to the resin composition is beneficial to improving the initial adhesion of the resin composition, that is, providing the initial surface adhesion between the resin and the wood fiberboard surface paper, so as to be more conducive to rolling and flattening after pasting.

[0008] Furthermore, the main resin is any one of urea-formaldehyde resin or its modified resin, melamine-formaldehyde resin or its modified resin, phenol-formaldehyde resin or its modified resin, silicone-acrylic emulsion, styrene-acrylic emulsion, acrylic emulsion, EVA emulsion, and pure acrylic emulsion; selecting a specific main resin can significantly improve the surface hardness of the coated resin layer, enhance the hardness or supporting force of the pad to achieve the effect of suppressing flashing, and at the same time enhance the bonding strength between the facing paper and the wood fiberboard; in this system, if the main resin is compounded with two or more resins, the bonding strength of the resin composition will deteriorate and lead to stratification.

[0009] Furthermore, the filler is any one or more of silicon micropowder, spherical silica powder, calcium carbonate, bentonite, kaolin, talcum powder, alumina powder, mica powder, and quartz powder.

[0010] Furthermore, the auxiliary agent is any one or more of formic acid, acetic acid, formic acid, hydrochloric acid, sulfuric acid, ammonium sulfate, ammonium persulfate, urotropine, monoethanolamine, diethanolamine, triethanolamine, and ethylenediamine hydrochloride; the inventors found that adding specific auxiliary agents to the resin composition can significantly improve the degree of curing of the resin composition and reduce the time for the resin composition to cure at room temperature. If too little auxiliary agent is added, the room temperature curing time of the resin is prolonged, which is not conducive to improving production efficiency. However, if too much auxiliary agent is added, the curing time of the glue layer is short, and the adaptation period of the production resin is short, which is also not conducive to production.

[0011] Furthermore, the leveling agent is one or more of natural plant castor oil, poly-alpha olefin, water-soluble olive oil, water-soluble almond oil, water-soluble coconut oil, water-soluble palm oil ester, alkylphenol polyoxyethylene ether, and octylphenol polyoxyethylene ether.

[0012] The present invention also provides a PCB drilling pad, comprising a wood fiber board, the resin composition layer coated on the upper and lower surfaces of the wood fiber board, and a surface paper layer attached to the surface of the resin composition layer. The present invention achieves the effects of reducing energy consumption, simplifying the process, and inhibiting the generation of drilling burrs by coating the resin composition layer on the wood fiber board and utilizing the high hardness and strong bonding properties of the resin composition cured at room temperature; attaching a piece of surface paper on the surface of the resin composition layer can utilize its bonding force to strongly bond the surface paper to form a whole; and the resin composition layer with high hardness after curing can achieve the effect of inhibiting burrs when drilling, thereby improving the quality of PCB drilling processing.

[0013] Furthermore, the thickness of the resin composition layer is 10-200 μm; the test method for the thickness of the coated resin composition layer is: cut a cross section of the coated wood fiberboard, polish it with 400 mesh, 800 mesh, and 2000 mesh sandpaper in turn, and observe and measure the thickness of the coated resin layer (referring to the single-layer film thickness) under a digital microscope; if the thickness of the resin composition layer is too thin, the adhesion between the resin composition and the surface paper will be reduced, and the burrs will increase, and the effect of suppressing the flash will not be achieved; if the resin composition layer is too thick, the surface hardness will be reduced, the cost of the product and the difficulty of the coating and bonding process will increase, and the effect of suppressing the flash will not be achieved.

[0014] Furthermore, the thickness of the resin composition layer is 50-100 μm.

[0015] Furthermore, the facial paper is any one of gorgeous paper, Polaroid paper or glassine paper, preferably single silicon glassine paper with one side subjected to release treatment and the other side untreated, with a release force of 20-300gf / 25mm; the square grammage of the facial paper is 20-120g / m 2 ; Select facial paper with a thickness of 20-200 μm, the facial paper can be selected from different colors (such as white, yellow, blue, green, etc.), and more preferably glassine paper with a surface pencil hardness of more than 2H.

[0016] Furthermore, the wood fiber board includes but is not limited to any one of medium density fiberboard, high density fiberboard or ultra-high density fiberboard, and the thickness of the wood fiber board is preferably 1.0-20 mm.

[0017] The present invention also provides a production process of the PCB drilling pad, comprising the following steps:

[0018] S1. Deashing the A side of the fiberboard, coating the fiberboard with a resin composition layer, and pre-baking the resin composition layer to obtain a laminated fiberboard, evaporating part of the water by pre-baking, and pre-baking can be beneficial for production under low temperature conditions, and the baking temperature is 25-90°C; then rolling the upper resin composition and laminating the surface paper to obtain a sticker fiberboard, and cutting the surface paper after heavy rolling, and grinding the edge paper;

[0019] S2. Using the same processing technology as that used to produce the A side, the B side of the wood fiber board is produced to obtain the PCB drilling pad.

[0020] The present invention does not require a high-temperature curing step when producing a pad for PCB drilling, which not only has the advantages of simple process and low energy consumption, but also can stabilize the moisture in the plate during the production process, reduce the warping deformation rate of the plate, and improve the quality of the pad.

[0021] Furthermore, the coating is roller coating, spray coating or flow coating.

[0022] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0023] (1) The resin composition provided by the present invention can be cured at room temperature, and the cured resin composition has high hardness and strong bonding force;

[0024] (2) The resin composition provided by the present invention uses a water-based resin, and no ventilation equipment is required to remove harmful substances during the curing process, and no substances harmful to the human body are volatilized;

[0025] (3) The PCB drilling pad provided by the present invention can suppress the generation of burrs during drilling and improve the drilling processing quality;

[0026] (4) The PCB drilling pad provided by the present invention has a simple production process and low energy consumption, and is produced at low temperature. During the preparation process, the pad can be prevented from warping and deformation, thereby improving the quality of the pad. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a schematic structural diagram of a PCB drilling pad of the present invention;

[0029] Figure 2 It is a schematic diagram of the production process of the PCB drilling pad of the present invention.

[0030] Reference numerals: 1 - surface paper layer; 2 - resin composition layer; 3 - wood fiber board. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0032] Example

[0033] The present invention is further described below in conjunction with specific examples and comparative examples. The following specific examples are all preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and are particularly not limited to the types of the various component raw materials used in the following specific examples.

[0034] 1. The sources of raw materials for the embodiments and comparative examples are as follows:

[0035] Unless otherwise specified, the raw materials used in the examples and comparative examples of the present invention are commercially available.

[0036] The preparation method of the resin composition is as follows: weighing each component of the formula by weight, mixing and dispersing at a high speed of 1000-2000 rpm, and controlling the viscosity at 8000-20000 mPa·S to obtain the resin composition.

[0037] 2. Various performance test methods

[0038] (1) Test on gel time of resin composition: Test was conducted in accordance with GB 12007.7-1989 “Test method for gel time of epoxy resin”.

[0039] (2) Pad drilling flash test: Tested according to IPC-A-600CN-2016 standard.

[0040] (3) Pencil hardness test: The test is carried out in accordance with GB / T 6739-2022 "Determination of film hardness of paints and varnishes by pencil hardness test".

[0041] (4) Pad warping test: The test is carried out according to the standard of GB / T 11718-2009 “Test method for warpage of printed circuit boards”.

[0042] Table 1. Resin composition formulations and effects of examples and comparative examples (in parts by weight)

[0043]

[0044] The resin compositions of Examples 1-3 prepared in Table 1 were coated on wood fiber boards with different thicknesses (20, 50, 100, 120 μm) and then laminated with surface paper to prepare PCB drilling pads. The prepared pads were subjected to drilling tests, and the results were as follows:

[0045] Table 2. PCB drilling pad drilling test results

[0046]

[0047]

[0048] The PCB drilling pads 1-3 with a coating thickness of 50 μm prepared in Table 2 of the present invention were subjected to a warpage deformation test with a UV pad with the same film thickness (UV coating thickness of 50 μm), and the results are as follows:

[0049] Table 3. PCB drilling pad warpage test results

[0050] Pad type 1d 2d 3d 4d 5d UV backing plate 1mm 2mm 2mm 3mm 3.5mm PCB drilling pad 1 0 mm 0mm 1mm 1mm 1.5mm PCB drilling pad 2 1mm 0.5mm 1mm 1.5mm 2mm PCB drilling pad 3 1mm 1.5mm 1mm 1.5mm 2.5mm

[0051] The resin composition of Examples 1-5 simultaneously contains a main resin, a water-soluble starch, a pigment, a filler and an auxiliary agent. The obtained resin composition can be cured at room temperature and has high hardness and strong bonding force. The PCB drilling pad prepared by using the resin composition of Examples 1-3 has a high pencil hardness and can significantly suppress the generation of flash during drilling. The prepared pad is not significantly warped and deformed compared to the UV pad, indicating that the PCB drilling pad prepared in the present application can replace the existing UV pad. The PCB drilling pad of the present invention adopts a specific resin composition as a coating layer, and utilizes its advantages of high hardness, strong bonding force and the ability to cure at room temperature. The prepared pad can significantly suppress the generation of flash during drilling, and the production process of the pad is simple, energy consumption is low, and it has broad application prospects.

[0052] Based on the tests on the hardness, adhesion and room temperature curing time of the resin composition in Table 1, and the test data on the pencil hardness, drilling flash and warping deformation of the pad in Tables 2-3, the resin composition prepared by Examples 1-5 and the PCB drilling pad prepared based on the resin composition have obvious advantages over the comparative example and can effectively meet the high standards of customers and the market.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A resin composition, characterized in that By weight, it includes the following components: The curing temperature of the resin composition is 5-40°C.

2. The resin composition according to claim 1, characterized in that The main resin is any one of urea-formaldehyde resin or its modified resin, melamine-formaldehyde resin or its modified resin, phenol-formaldehyde resin or its modified resin, silicone-acrylic emulsion, styrene-acrylic emulsion, acrylic emulsion, EVA emulsion and pure acrylic emulsion.

3. The resin composition according to claim 1, characterized in that The filler is any one or more of silicon micropowder, spherical silica powder, calcium carbonate, bentonite, kaolin, talcum powder, alumina powder, mica powder, and quartz powder.

4. The resin composition according to claim 1, characterized in that The auxiliary agent is any one or more of formic acid, acetic acid, formic acid, hydrochloric acid, sulfuric acid, ammonium sulfate, ammonium persulfate, urotropine, monoethanolamine, diethanolamine, triethanolamine, and ethylenediamine hydrochloride.

5. The resin composition according to claim 1, characterized in that: The leveling agent is one or more of natural plant castor oil, poly-alpha olefin, water-soluble olive oil, water-soluble almond oil, water-soluble coconut oil, water-soluble palm oil ester, alkylphenol polyoxyethylene ether, and octylphenol polyoxyethylene ether.

6. A PCB drilling pad, characterized in that: The invention comprises a wood fiber board, a resin composition layer according to any one of claims 1 to 5 coated on the upper and lower surfaces of the wood fiber board, and a surface paper layer attached to the surface of the resin composition layer.

7. The PCB drilling pad according to claim 6, characterized in that: The thickness of the resin composition layer is 10-200 μm, preferably 50-100 μm.

8. The PCB drilling pad according to claim 6, characterized in that: The facial paper is any one of gorgeous paper, Polaroid paper or glassine paper.

9. The production process of the PCB drilling backing plate according to any one of claims 6 to 8, characterized in that: The steps include: S1. The A side of the fiberboard is deashed, a resin composition layer is coated on the fiberboard, the resin composition layer is pre-baked to obtain a coated fiberboard, and then the upper layer of the resin composition is rolled and laminated with a face paper to obtain a sticker fiberboard, and the face paper is cut after heavy roller lamination, and the edge paper is sharpened; S2. Produce and process the wood fiber board surface B in the same manner as surface A to obtain the PCB drilling pad.

10. The production process according to claim 9, characterized in that: The coating is performed by roller coating, spray coating or flow coating.

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