Cover plate coating for PCB drilling and preparation method and application thereof

Abstract

The invention provides a cover plate coating for PCB drilling as well as a preparation method and application of the cover plate coating. The cover plate coating for PCB drilling comprises the following components: polymer resin, powder filler, a plasticizer compound additive and a coating additive. According to the cover plate coating for drilling, provided by the invention, the plasticizer compound additive is added, the characteristic of compatibility of the plasticizer compound additive and a resin system is utilized, the proportion of an amorphous region in the coating is improved, and relatively low coating hardness is kept under the condition of high filler proportion in the coating, so that the coating has good mechanical property and drilling property, is not easy to crack, and has the advantages of low cost and good application prospect. And the coating thickness is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of circuit manufacturing, and relates to a PCB cover plate, and in particular to a cover plate coating for PCB drilling, and a preparation method and application thereof. Background Art

[0002] PCB (Printed Circuit Board) is an important electronic component. With the advent of the AI ​​wave, the demand for high-order HDI (High-Density Interconnect) boards is becoming increasingly significant. High-order HDI boards have higher circuit density and smaller guide holes, which can meet the downstream applications' requirements for small size, low loss, high frequency and high speed.

[0003] The production and processing of PCB involves multiple process steps such as circuit production and drilling. Among them, drilling is a key step in PCB processing, the purpose of which is to achieve the connection between circuits on different layers and the installation of components. The cover plate for PCB drilling (referred to as the cover plate) is an auxiliary material placed on the surface of the PCB to be processed during mechanical drilling of the PCB to meet the requirements of the processing technology. The performance of the cover plate greatly affects the effect of the drilling process. For example, if the hardness of the cover plate is too high, it will lead to a decrease in hole position accuracy, an increase in the maximum offset, an increase in drill needle wear, an increase in the needle breakage rate, and an increase in hole roughness. Due to the increasing requirements for high-precision PCBs, higher requirements are also placed on the performance of the cover plate, such as hole position accuracy, hole quality, and chip removal.

[0004] At present, the cover plate commonly used in the drilling process is an aluminum foil as a substrate, and a polymer resin coating is coated on the aluminum foil.

[0005] CN114456678A discloses a PCB cover plate with improved hole position accuracy, and a preparation method and application thereof. The polymer resin coating provided on the aluminum sheet includes a thermosetting resin, a curing agent, ultrafine powder, ethylene glycol polymer, a defoaming agent, a leveling agent and a dispersant. The polymer resin coating has a low hardness, thereby improving the hole position accuracy, buffering the drill bit, absorbing the heat of the drill bit, lubricating the drill bit, and reducing wire entanglement.

[0006] CN114773980A discloses a PCB coated aluminum substrate and a preparation method thereof. The raw materials of the coating layer of the aluminum foil layer include fat, glycerol, hydroxymethyl cellulose, dimethylsiloxane, triethanolamine, ethylenediamine, auxiliary agent A and auxiliary agent B. The auxiliary agent A includes powder filler, and the auxiliary agent B includes rhamnolipid and sodium dodecyl sulfate. Through the resin and auxiliary agent components, a coating with appropriate hardness and toughness is obtained, so that the cover plate has good hole position accuracy and hole wall quality, and there is no entanglement.

[0007] The use of fillers in PCB drilling cover plate coatings can help mechanical drilling chips and extend the life of the drill bit, which plays an important role in the stability of the drilling process. However, the proportion of fillers in existing PCB drilling cover plate coatings is relatively low, and increasing the proportion of fillers easily leads to increased hardness of the film layer, severe cracking tendency, and limited coating thickness. Therefore, it is necessary to provide a coating formula with lower hardness to solve the problems existing in existing PCB drilling cover plate coatings. Summary of the invention

[0008] The purpose of the present invention is to provide a cover plate coating for PCB drilling, and a preparation method and application thereof, by adding and synergistically proportioning powder fillers and plasticizer compounds in the coating, while ensuring good mechanical processing properties of the coating, reducing the hardness of the coating and improving the drilling effect.

[0009] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a cover plate coating for PCB drilling, wherein the components of the cover plate coating for PCB drilling include: a polymer resin, a powder filler, a plasticizer compound additive and a coating additive.

[0011] The coating for PCB drilling provided by the present invention is based on a polymer resin, and powder fillers and plasticizer compound additives are added. The powder fillers make the coating have good mechanical properties such as stability and wear resistance, which is helpful to promote chip removal in mechanical drilling and extend the life of the drill bit. By virtue of the compatibility of the plasticizer compound additive with the resin system, the crystalline region or amorphous region of the polymer resin is inserted into the polymer, the chain segments of the resin are separated, the intermolecular force is weakened, the existence of the crystalline region in the coating system is greatly reduced, and the proportion of the amorphous region is increased, thereby reducing the increase in the coating hardness caused by the increase in the filler ratio, making the coating softer, and the system has a lower Tg (glass transition temperature) point, is not easy to crack during the coating production process, and effectively increases the coating thickness, which can reach more than 100 microns.

[0012] Preferably, the plasticizer compound auxiliary agent includes a first plasticizer auxiliary agent and / or a second plasticizer auxiliary agent.

[0013] Preferably, the first plasticizer auxiliary comprises C 20 -C 26 Epoxides, C 18 -C 28 Fatty acid ester compounds, C8-C 16 Polyol ester compounds, C8-C 14 Phthalate esters, C 22 -C 26 Aliphatic dibasic acid ester compounds or C 33 -C50 Any one or a combination of at least two of the trimellitic acid ester compounds.

[0014] Exemplarily, the epoxy compound includes epoxidized soybean oil and / or epoxidized octyl oleate.

[0015] Exemplarily, the fatty acid ester compound includes butyl oleate and / or butyl stearate.

[0016] Exemplarily, the polyol ester compound includes tributyrin and / or triacetin.

[0017] Exemplarily, the phthalate compound includes dimethyl phthalate and / or di-n-octyl phthalate.

[0018] Exemplarily, the aliphatic dibasic acid ester compound includes dibutyl sebacate and / or di(2-ethylhexyl) adipate.

[0019] Exemplarily, the trimellitic acid ester compound includes tri-isooctyl trimellitate and / or tetraoctyl pyromellitate.

[0020] Preferably, the second plasticizer auxiliary comprises C 12 -C 30 Chlorinated plasticizers and / or C8-C 14 of phosphate compounds.

[0021] Exemplarily, the chlorine-containing plasticizer includes dichloroethyl phthalate and / or chlorinated paraffin.

[0022] Exemplarily, the phosphate ester compound includes tributyl phosphate and / or triphenyl phosphate.

[0023] Preferably, the mass compatibility ratio of the first plasticizer auxiliary to the polymer resin is (0.8-1.2):1, for example, it can be 0.8:1, 0.9:1, 1:1, 1.1:1 or 1.2:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the mass compatibility ratio of the second plasticizer auxiliary to the resin is (0.1-0.4):1, for example, it can be 0.1:1, 0.2:1, 0.3:1, 0.33:1 or 0.4:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] The mass compatibility ratio is the mass ratio of the plasticizer to the resin polymer when the plasticizer and the resin polymer are mixed and no phase separation occurs.

[0026] The first plasticizer additive has good compatibility with the resin system and can be inserted into the amorphous region of the polymer as well as the crystalline region, which ensures that the resin chain segments are separated, weakens the intermolecular forces, makes it easier to move, and thus reduces the hardness of the system; the second plasticizer additive has slightly worse compatibility with the resin system than the first plasticizer compound additive and can be inserted into the amorphous region or crystalline region of the polymer.

[0027] Preferably, the plasticizer compound auxiliary agent includes a first plasticizer auxiliary agent and a second plasticizer auxiliary agent.

[0028] When the first plasticizer auxiliary and the second plasticizer auxiliary are used in combination, through the synergistic cooperation of the two, the auxiliary is not easy to be separated or seeped out due to changes in the environment, working conditions, etc., causing fluctuations in product hardness, and the product stability is good.

[0029] In the present invention, the preparation method of the phthalate compound of the first plasticizer auxiliary comprises:

[0030] (1) Esterification: Phthalic anhydride and 1,6-hexanediol are added to a reactor at a molar ratio of 1:2.5 for esterification reaction, and a required amount of p-toluenesulfonic acid catalyst is added to the reactor at the same time, the catalyst amount is 3-4% of the total mass of the reaction materials, and then slowly heated and stirred, maintaining the reflux temperature at 170-180° C., and the reaction is stopped when the acid ester in the reaction system drops to 0.8 mgKOH / g;

[0031] (2) Primary dealcoholization: The dihexyl phthalate esterified material after the reaction is completed is transferred from the reactor to the primary dealcoholization reactor. During the primary dealcoholization process, the reactor must be kept under negative pressure, with the vacuum degree maintained at 0.1-0.15 MPa, and the temperature is slowly increased to 140-150°C to complete the initial removal of 1,6-hexanediol.

[0032] (3) Re-dealcoholization: The pressure in the reactor is controlled at -0.08 MPa to -0.09 MPa, and then the materials in the dealcoholization reactor are heated by steam. After the materials in the reactor reach 160° C., 0.13-0.18 MPa steam is introduced into the dealcoholization reactor to strip the materials in the reactor, and the time is controlled to be 15-20 min;

[0033] (4) Filtration: After the material has passed the inspection, it is filtered by extrusion filtration, and the finished product is pumped from the dealcoholization kettle into the finished product tank for standby use.

[0034] Preferably, the components of the PCB drilling cover plate coating include, by weight: 20-45 parts of polymer resin, 0.1-85 parts of powder filler, 0.2-3 parts of plasticizer compound additives, and 0.5-1 parts of coating additives.

[0035] The weight portion of the polymer resin is 20-45 parts, for example, it can be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts or 45 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0036] The weight proportion of the powder filler is 0.1-85 parts, for example, it can be 0.1 parts, 0.5 parts, 1 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts or 85 parts, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0037] The weight portion of the plasticizer compound auxiliary agent is 0.2-3 parts, for example, it can be 0.2 parts, 0.5 parts, 1 parts, 1.5 parts, 2 parts, 2.5 parts or 3 parts, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0038] The weight portion of the coating additive is 0.5-1 part, for example, it can be 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part or 1 part, but it is not limited to the listed values, and other values ​​not listed in the numerical range are also applicable.

[0039] Preferably, the components of the cover plate coating for PCB drilling include, by weight: 20-45 parts of polymer resin, 0.1-85 parts of powder filler, 0.5-2 parts of a first plasticizer additive, 0.2-1 parts of a second plasticizer additive, and 0.5-1 parts of a coating additive.

[0040] The weight portion of the first plasticizer auxiliary is 0.5-2 parts, for example, it can be 0.5 parts, 0.6 parts, 0.8 parts, 1 parts, 1.2 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.8 parts or 2 parts, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0041] The weight portion of the second plasticizer auxiliary is 0.2-1 part, for example, it can be 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part or 1 part, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0042] Preferably, the powder filler includes an organic powder filler and / or an inorganic powder filler.

[0043] Preferably, the organic powder filler comprises polytetrafluoroethylene.

[0044] Adding organic filler polytetrafluoroethylene to the coating system can make the coating have excellent chemical stability and low friction coefficient, which can significantly improve the anti-fouling and wear resistance of the coating, reduce the accumulation of stains and wear on the coating surface, and can also increase the hole limit, extend the service life of the drill bit and improve the hole position accuracy.

[0045] Preferably, the inorganic powder filler comprises any one of kaolin, wollastonite, calcium carbonate, talc, mica powder, barium hydroxide or aluminum hydroxide, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of calcium carbonate and kaolin, a combination of wollastonite and barium hydroxide, a combination of calcium carbonate and talc, a combination of calcium carbonate and mica powder, a combination of calcium carbonate and aluminum hydroxide, a combination of calcium carbonate, kaolin and talc, a combination of calcium carbonate, wollastonite and mica powder, and a combination of calcium carbonate, kaolin, talc, mica powder and aluminum hydroxide.

[0046] Adding calcium carbonate to inorganic powder fillers can increase the thickness of the film layer and have good dispersibility; using kaolin and / or wollastonite can improve the suspension stability and thixotropy of the coating, ensure the stability of the system and enhance the adhesion of the film; utilizing the layered structure of talcum powder can improve the flatness of the film; mica powder can improve the oxidation resistance of the film; barium hydroxide and / or aluminum hydroxide have excellent chemical stability and low friction coefficient, which can significantly improve the anti-fouling and wear resistance of the coating and reduce stain accumulation and wear on the coating surface.

[0047] Preferably, the polymer resin includes any one of polyurethane resin, amino resin, epoxy resin, acrylic resin, phenolic resin or polyester resin, or a combination of at least two of them. Typical but non-limiting combinations include a combination of polyurethane resin and amino resin, a combination of epoxy resin and acrylic resin, a combination of phenolic resin and polyester resin, a combination of polyurethane resin, amino resin and epoxy resin, or a combination of acrylic resin, phenolic resin and polyester resin.

[0048] Preferably, the coating additive includes any one of a wetting agent, a defoamer, a film-forming aid or a cross-linking agent, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of a wetting agent and a defoamer, a combination of a film-forming aid and a cross-linking agent, a combination of a wetting agent, a defoamer and a film-forming aid, a combination of a defoamer, a film-forming aid and a cross-linking agent, or a combination of a wetting agent, a defoamer, a film-forming aid and a cross-linking agent.

[0049] In a second aspect, the present invention provides a method for preparing the cover plate coating for PCB drilling according to the first aspect, the preparation method comprising:

[0050] According to the components of the cover plate coating for PCB drilling, raw materials and solvents are mixed and dispersed to form a homogeneous coating, the homogeneous coating is coated on a substrate, and then cured to obtain the cover plate coating for PCB drilling.

[0051] Preferably, the solvent comprises water, C2-C 20 Alcohol compounds, C2-C 20 Ketone compounds, C2-C 20 Ester compounds or C4-C 20 A combination of at least two of any one of the hydrocarbon compounds.

[0052] Preferably, the amount of the solvent used is 5-15 parts by weight of the components of the cover plate coating for PCB drilling, for example, 5 parts, 8 parts, 10 parts, 12 parts or 15 parts, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0053] Preferably, the curing temperature is 100-150°C, for example, 100°C, 110°C, 120°C, 130°C, 140°C or 150°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0054] Preferably, the dispersing process further includes sand grinding.

[0055] In a third aspect, the present invention provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling comprises an aluminum foil substrate and the cover plate coating for PCB drilling according to the first aspect disposed on the aluminum foil substrate.

[0056] Preferably, the thickness of the cover plate coating for PCB drilling is 30-120 μm, for example, it can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm or 120 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0057] Preferably, the thickness of the aluminum foil substrate is 0.08-0.2 mm, for example, 0.08 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.18 mm or 0.2 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The drilling cover plate coating provided by the present invention adds a plasticizer compound additive, utilizes its compatibility with the resin system, improves the proportion of amorphous areas in the coating, maintains a low coating hardness under the condition of a high filler ratio in the coating, and the coating hardness is below 4B, so that the coating has good mechanical properties and drilling performance, is not easy to crack, and effectively improves the coating thickness. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0061] Example 1

[0062] This embodiment provides a cover plate coating for PCB drilling.

[0063] The components of the PCB drilling cover plate coating include, by weight: 30 parts of polymer resin, 60 parts of powder filler, 1 part of a first plasticizer additive, 0.5 parts of a second plasticizer additive, and 0.8 parts of a coating additive.

[0064] Wherein, the polymer resin is polyurethane resin.

[0065] The powder filler is polytetrafluoroethylene, wollastonite, talcum powder, mica powder and calcium carbonate added in equal amounts.

[0066] The first plasticizer auxiliary is dihexyl phthalate, and the second plasticizer auxiliary is chlorinated paraffin.

[0067] The coating additives are a wetting agent (polyoxyethylene ether wetting agent), a defoaming agent (organic silicon defoaming agent), a film-forming aid (propylene glycol methyl ether acetate) and a crosslinking agent (amine crosslinking agent) added in equal amounts.

[0068] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0069] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0070] The preparation method of the cover plate for PCB drilling is as follows:

[0071] According to the components of the cover plate coating for PCB drilling, the raw materials and the solvent are mixed for dispersion and sand grinding, wherein the amount of the solvent is 10 parts by weight of the components of the cover plate coating for PCB drilling, and the solvent is water and propanol of equal mass to form a homogeneous coating, and the homogeneous coating is coated on an aluminum foil substrate, and then baked to obtain the cover plate for PCB drilling.

[0072] Example 2

[0073] This embodiment provides a cover plate coating for PCB drilling.

[0074] The components of the PCB drilling cover plate coating include, by weight: 45 parts of polymer resin, 30 parts of powder filler, 0.5 parts of a first plasticizer additive, 0.2 parts of a second plasticizer additive, and 0.5 parts of a coating additive.

[0075] Wherein, the polymer resin is polyurethane resin.

[0076] The powder filler is polytetrafluoroethylene, wollastonite, talcum powder, mica powder and calcium carbonate added in equal amounts.

[0077] The first plasticizer auxiliary is dihexyl phthalate, and the second plasticizer auxiliary is chlorinated paraffin.

[0078] The coating additives are a wetting agent (polyoxyethylene ether wetting agent), a defoaming agent (organic silicon defoaming agent), a film-forming aid (propylene glycol methyl ether acetate) and a crosslinking agent (amine crosslinking agent) added in equal amounts.

[0079] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0080] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0081] The preparation method of the cover plate for PCB drilling is as follows:

[0082] According to the components of the cover plate coating for PCB drilling, the raw materials and the solvent are mixed for dispersion and sand grinding, wherein the amount of the solvent is 5 parts by weight of the components of the cover plate coating for PCB drilling, and the solvent is equal in mass of water and propanol to form a homogeneous coating, which is coated on an aluminum foil substrate and then baked to obtain the cover plate for PCB drilling.

[0083] Example 3

[0084] This embodiment provides a cover plate coating for PCB drilling.

[0085] The components of the PCB drilling cover plate coating include, by weight: 20 parts of polymer resin, 85 parts of powder filler, 2 parts of a first plasticizer additive, 1 part of a second plasticizer additive, and 1 part of a coating additive.

[0086] Wherein, the polymer resin is polyurethane resin.

[0087] The powder filler is polytetrafluoroethylene, wollastonite, talcum powder, mica powder and calcium carbonate added in equal amounts.

[0088] The first plasticizer auxiliary is dihexyl phthalate, and the second plasticizer auxiliary is chlorinated paraffin.

[0089] The coating additives are a wetting agent (polyoxyethylene ether wetting agent), a defoaming agent (organic silicon defoaming agent), a film-forming aid (propylene glycol methyl ether acetate) and a crosslinking agent (amine crosslinking agent) added in equal amounts.

[0090] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0091] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0092] The preparation method of the cover plate for PCB drilling is as follows:

[0093] According to the components of the cover plate coating for PCB drilling, the raw materials and the solvent are mixed for dispersion and sand grinding, wherein the amount of the solvent is 15 parts by weight of the components of the cover plate coating for PCB drilling, and the solvent is water and propanol of equal mass to form a homogeneous coating, which is coated on an aluminum foil substrate and then baked to obtain the cover plate for PCB drilling.

[0094] Example 4

[0095] This embodiment provides a cover plate coating for PCB drilling.

[0096] Compared with Example 1, the components of the cover plate coating for PCB drilling are as follows: the first plasticizer auxiliary agent is replaced by dioctyl adipate, the second plasticizer auxiliary agent is replaced by trioctyl phosphate, and the rest are the same as Example 1.

[0097] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0098] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0099] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0100] Example 5

[0101] This embodiment provides a cover plate coating for PCB drilling.

[0102] Compared with Example 1, the components of the cover plate coating for PCB drilling are the same as those in Example 1, except that the first plasticizer auxiliary agent is replaced by epoxidized oil.

[0103] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0104] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0105] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0106] Example 6

[0107] This embodiment provides a cover plate coating for PCB drilling.

[0108] Compared with Example 1, the components of the cover plate coating for PCB drilling do not include the first plasticizer auxiliary, and the rest are the same as those in Example 1.

[0109] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0110] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0111] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0112] Example 7

[0113] This embodiment provides a cover plate coating for PCB drilling.

[0114] Compared with Example 1, the components of the cover plate coating for PCB drilling are set to 3 parts by weight of the first plasticizer auxiliary agent, and the rest are the same as Example 1.

[0115] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0116] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0117] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0118] Example 8

[0119] This embodiment provides a cover plate coating for PCB drilling.

[0120] Compared with Example 1, the components of the cover plate coating for PCB drilling do not include the second plasticizer auxiliary, and the rest are the same as those in Example 1.

[0121] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0122] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0123] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0124] Example 9

[0125] This embodiment provides a cover plate coating for PCB drilling.

[0126] Compared with Example 1, the components of the cover plate coating for PCB drilling are set to 2 parts by weight of the second plasticizer auxiliary.

[0127] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0128] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0129] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0130] Example 10

[0131] This embodiment provides a cover plate coating for PCB drilling.

[0132] Compared with Example 1, the components of the cover plate coating for PCB drilling are the same as those of Example 1, except that the mass of polytetrafluoroethylene in the powder filler is replaced by aluminum hydroxide.

[0133] This embodiment also provides a cover plate for PCB drilling, wherein the cover plate for PCB drilling includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling disposed on the aluminum foil substrate.

[0134] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0135] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0136] Comparative Example 1

[0137] This comparative example provides a cover plate coating for PCB drilling.

[0138] The components of the PCB drilling cover plate coating include, by weight: 30 parts of polymer resin, 60 parts of powder filler, and 0.8 parts of coating additive.

[0139] Wherein, the polymer resin is polyurethane resin.

[0140] The powder filler is polytetrafluoroethylene, wollastonite, talcum powder, mica powder and calcium carbonate added in equal amounts.

[0141] The coating additives are a wetting agent (polyoxyethylene ether wetting agent), a defoamer (organic silicon defoamer), a film-forming aid (propylene glycol methyl ether acetate) and a crosslinking agent (amine crosslinking agent) added in equal amounts.

[0142] That is, compared with Example 1, the first auxiliary plasticizer and the second auxiliary plasticizer are not added to the coating.

[0143] This comparative example also provides a cover plate for PCB drilling, which includes an aluminum foil substrate and the above-mentioned cover plate coating for PCB drilling arranged on the aluminum foil substrate.

[0144] The thickness of the aluminum foil substrate is 120 μm, and the thickness of the PCB drilling cover plate coating is 70 μm.

[0145] The preparation method of the cover plate for PCB drilling is the same as that of Example 1.

[0146] Performance Testing

[0147] The PCB drilling cover plates provided in the embodiments and comparative examples were subjected to drilling tests.

[0148] The test conditions of the drilling test are: drilling machine: HANS-F6M; drill bit: Φ0.2mm*4.5cm; drilling parameters: S180krpm, F2.5m / min, R25m / min; substrate: HTG0.8*L8*3PNL; pad: phenolic board 1.5mm. The test results are listed in Table 1.

[0149] Table 1

[0150]

[0151]

[0152] It can be seen from Table 1 that the coating formula provided by the present invention introduces a plasticizer under the condition of a high filler ratio, which can significantly reduce the hardness of the coating and simultaneously improve the hole position accuracy of the coating, reduce the maximum offset and hole coarseness, and effectively improve the mechanical processing performance of the coating.

[0153] Compared with Example 1, in Examples 6 and 8, only one plasticizer additive is used, and the hardness of the coating is relatively high, which is not conducive to mechanical processing; in Example 7, further increasing the amount of the first plasticizer additive does not significantly improve the coating performance; in Example 8, further increasing the amount of the second plasticizer additive causes the coating performance to be unstable, and the hardness increases; in Example 10, compared with polytetrafluoroethylene, the use of aluminum hydroxide reduces the hole position accuracy. It can be seen that the use of polytetrafluoroethylene as a filler significantly improves the hole position accuracy.

[0154] In Comparative Example 1, no plasticizer additive is used. Under the condition of high filler ratio, the hardness of the coating is significantly larger, resulting in a significant increase in drilling offset and hole roughness. The processing conditions are not conducive to drilling and the performance is poor.

[0155] In summary, the drilling cover plate coating provided by the present invention adds a plasticizer compound additive, utilizes its compatibility with the resin system, improves the proportion of amorphous areas in the coating, maintains a low coating hardness under the condition of a high filler ratio in the coating, and the coating hardness is below 4B, so that the coating has good mechanical properties and drilling performance, is not easy to crack, and effectively increases the coating thickness.

[0156] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A cover plate coating for PCB drilling, characterized in that: The components of the cover plate coating for PCB drilling include: polymer resin, powder filler, plasticizer compound additive and coating additive.

2. The cover plate coating for PCB drilling according to claim 1, characterized in that: The plasticizer compound auxiliary agent includes a first plasticizer auxiliary agent and / or a second plasticizer auxiliary agent; Preferably, the mass compatibility ratio of the first plasticizer auxiliary to the polymer resin is (0.8-1.2):1; Preferably, the mass compatibility ratio of the second plasticizer auxiliary to the resin is (0.1-0.4):1; Preferably, the first plasticizer auxiliary comprises C 20 -C 26 Epoxides, C 18 -C 28 Fatty acid ester compounds, C8-C 16 Polyol ester compounds, C8-C 14 Phthalate esters, C 22 -C 26 Aliphatic dibasic acid ester compounds or C 33 -C 50 Any one or a combination of at least two of the trimellitic acid ester compounds; Preferably, the second plasticizer auxiliary comprises C 12 -C 30 Chlorinated plasticizers and / or C8-C 14 of phosphate compounds.

3. The cover plate coating for PCB drilling according to claim 1 or 2, characterized in that: The components of the PCB drilling cover plate coating include, by weight: 20-45 parts of polymer resin, 0.1-85 parts of powder filler, 0.2-3 parts of plasticizer compound additive, and 0.5-1 parts of coating additive; Preferably, the components of the cover plate coating for PCB drilling include, by weight: 20-45 parts of polymer resin, 0.1-85 parts of powder filler, 0.5-2 parts of a first plasticizer additive, 0.2-1 parts of a second plasticizer additive, and 0.5-1 parts of a coating additive.

4. The cover plate coating for PCB drilling according to any one of claims 1 to 3, characterized in that: The powder filler includes an organic powder filler and / or an inorganic powder filler; Preferably, the organic powder filler comprises polytetrafluoroethylene; Preferably, the inorganic powder filler includes any one of kaolin, wollastonite, calcium carbonate, talc, mica powder, barium hydroxide or aluminum hydroxide, or a combination of at least two thereof.

5. The cover plate coating for PCB drilling according to any one of claims 1 to 4, characterized in that: The polymer resin includes any one of polyurethane resin, amino resin, epoxy resin, acrylic resin, phenolic resin or polyester resin, or a combination of at least two of them.

6. The cover plate coating for PCB drilling according to any one of claims 1 to 5, characterized in that: The coating additives include any one of a wetting agent, a defoaming agent, a film-forming aid or a cross-linking agent, or a combination of at least two of them.

7. A method for preparing a cover plate coating for PCB drilling according to any one of claims 1 to 6, characterized in that: The preparation method comprises: According to the components of the cover plate coating for PCB drilling, raw materials and solvents are mixed and dispersed to form a homogeneous coating, the homogeneous coating is coated on a substrate, and then cured to obtain the cover plate coating for PCB drilling.

8. The preparation method according to claim 7, characterized in that: The solvent includes water, C2-C 20 Alcohol compounds, C2-C 20 Ketone compounds, C2-C 20 Ester compounds or C4-C 20 A combination of at least two of any one of the hydrocarbon compounds; Preferably, the amount of the solvent used is 5-15 parts by weight based on the components of the cover plate coating for PCB drilling; Preferably, the curing temperature is 100-150°C; Preferably, the dispersing process further includes sand grinding.

9. A cover plate for PCB drilling, characterized in that: The cover plate for PCB drilling comprises an aluminum foil substrate and a cover plate coating for PCB drilling according to any one of claims 1 to 6 disposed on the aluminum foil substrate.

10. The cover plate for PCB drilling according to claim 9, characterized in that: The thickness of the PCB drilling cover plate coating is 30-200 μm; Preferably, the thickness of the aluminum foil substrate is 0.08-0.2 mm.

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