A heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling and its preparation method

Abstract

The present invention relates to the technical field of coated aluminum sheets, and discloses a heat-dissipating coated aluminum sheet for drilling holes in high-frequency, high-speed, and high-layer boards, and a preparation method thereof. The heat-dissipating coated aluminum sheet for drilling holes in high-frequency, high-speed, and high-layer boards comprises an aluminum foil substrate and a composite water-soluble polymer resin layer coated on the upper surface of the aluminum foil substrate. The materials used to prepare the composite water-soluble polymer resin layer include thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, solid-solid phase change material, solid-gas phase change material, solid-liquid phase change material, filler, lubricating material, and additives. The heat-dissipating coated aluminum sheet for drilling holes in high-frequency, high-speed, and high-layer boards provided by the present invention can significantly reduce the drilling temperature, is conducive to the improvement of CPK, reduces the risks of hole plugging, debris, wire entanglement, and needle breakage, and the film layer can be completely soluble in water, which is convenient for cleaning drill cuttings in the hole in the later stage, and is suitable for drilling holes in high-frequency, high-speed, and high-layer boards.

Description

Technical Field

[0001] The present invention relates to the technical field of film-coated aluminum sheets, and in particular to a heat-dissipating film-coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of 5G communications, artificial intelligence, automotive anti-collision systems and other fields, PCB boards have also been driven towards high frequency, high speed, and high multi-layer development. When mechanically drilling high-frequency, high-speed, and high-layer printed circuit boards, problems such as high heat generation, low hole position accuracy (CPK), short drill bit life, low drilling efficiency, and difficulty in removing drill chips are often encountered. There is an urgent need to develop a coated aluminum sheet with rapid heat dissipation, improved CPK, extended drill bit life, and no risks of wire entanglement, hole plugging, or debris.

[0003] The heat dissipation principle of ordinary heat-dissipating coated aluminum sheets is mainly to utilize the surface resin component to absorb heat by solid-liquid phase change under the local high temperature environment of drilling. However, when it melts, it will form a melt with high viscosity. Drill cuttings are very easy to adhere to the drill bit, aluminum sheet, and substrate, thereby causing problems such as wire entanglement, hole plugging, debris, and dust accumulation. This problem will cause abnormalities such as drill bit breakage and single hole deviation, seriously affecting the quality and efficiency of drilling. In addition, the surface film layer of ordinary coated aluminum sheets is non-water-soluble or poorly water-soluble, which is not conducive to the cleaning of drill cuttings in the hole in the later stage, bringing quality risks to customers.

[0004] Therefore, the existing technology still needs to be improved and developed. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a heat-dissipating coated aluminum sheet for drilling high-frequency, high-speed, and high-layer boards and a preparation method thereof, aiming to solve the problem that the existing coated aluminum sheet has poor heat dissipation performance, resulting in poor drilling quality of high-frequency, high-speed, and high-layer boards.

[0006] The technical solutions of the present invention are as follows:

[0007] A heat-dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, comprising an aluminum foil substrate and a composite water-soluble polymer resin layer coated on the upper surface of the aluminum foil substrate. The materials used to prepare the composite water-soluble polymer resin layer include thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, solid-solid phase change material, solid-gas phase change material, solid-liquid phase change material, filler, lubricating material, and additives.

[0008] The heat dissipation coated aluminum sheet for high-frequency, high-speed and high-layer board drilling, wherein the solid-solid phase change material is (C n H 2n+1 NH3)2MX4 layered perovskite material, wherein n=8-18, M is a divalent metal, and X is a halogen atom.

[0009] The heat dissipation coated aluminum sheet for high-frequency, high-speed and high-layer board drilling, wherein the solid-gas phase change material is one or both of sublimated salicylic acid and 2,4,6-triisopropyl-1,3,5-trioxane.

[0010] In the heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, the solid-liquid phase change material is one or both of polyvinyl pyrrolidone and low-molecular-weight polyethylene glycol.

[0011] The heat dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, wherein the filler is one or more of talc, calcium carbonate, barium sulfate, calcined kaolin, mica powder, bentonite, and silicon dioxide.

[0012] The heat dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, wherein the lubricating material is one or both of wax emulsion and nonylphenol polyoxyethylene ether.

[0013] The heat dissipating film-coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, wherein the auxiliary agent is one or more of a leveling agent, a film auxiliary agent, a dispersant, and a defoaming agent.

[0014] The heat dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling has a thickness of 70-250 μm for the aluminum foil substrate and a thickness of 20-100 μm for the composite water-soluble polymer resin layer.

[0015] A method for preparing a heat dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to the present invention comprises the following steps:

[0016] Preparing thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol in advance;

[0017] Adding the thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol into hot water to dissolve it, then adding the solid-liquid phase change material and stirring to obtain a solid-liquid phase change mixed material solution;

[0018] After adding the dispersant into water and stirring evenly, the solid-solid phase change material and filler are added, stirred evenly, and then ground to obtain a solid-solid phase change mixed material solution;

[0019] dissolving a solid-gas phase change material into an ethanol solution to obtain a solid-gas phase change mixed material solution;

[0020] Gradually adding the solid-gas phase change mixed material solution and the solid-solid phase change mixed material solution into the solid-liquid phase change mixed material solution, and adding a lubricating material, a leveling agent, a defoaming agent and a membrane aid, stirring evenly, filtering and vacuuming to defoam, to obtain a mixed glue solution;

[0021] The mixed adhesive solution is coated on the surface of an aluminum foil substrate, and after drying, the heat dissipation coated aluminum sheet for drilling high-frequency, high-speed, and high-layer boards is obtained.

[0022] The method for preparing the heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, wherein the step of preparing the thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol comprises:

[0023] Methanol and vinyl acetate were added to a reaction vessel and stirred evenly under a nitrogen atmosphere. The temperature of the reaction vessel was raised to 60-70°C, and AIBN was added to initiate the reaction. Acrylic acid (1%-5% of the amount of vinyl acetate) was then added dropwise. The reaction was continued for 5-8 hours. After the reaction was completed, the copolymer solution was precipitated, filtered, and dried.

[0024] The copolymer is prepared into a methanol solution and a NaOH methanol solution is added to perform alcoholysis at 50-70° C. After the reaction is completed for 1-2 hours, the carboxyl-containing PVA is obtained by removing impurities, filtering, and drying;

[0025] The carboxyl-containing PVA and glycerol are added into a twin-screw extruder in a certain proportion, and thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, namely TCPVA resin, is obtained through plasticization and shearing.

[0026] Beneficial effects: The heat dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling provided by the present invention adopts thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol (TCPVA) instead of traditional resin emulsion and ordinary PVA and other materials as the main bonding resin, which has better water solubility, storage stability, and melt fluidity, and the melt viscosity decreases with the increase of the drill bit shear rate, reducing the adhesion of drill cuttings to the drill bit, aluminum sheet, holes, etc., and also plays a certain lubricating role on the drill bit, extending the life of the drill bit, and is fully water-soluble after film formation, which is convenient for the client to remove the drill cuttings in the holes in the later water washing process; the present invention adopts three types of phase change materials to achieve the reduction of the drill bit temperature, among which TCPVA and solid-liquid phase change material undergo solid-liquid phase change and absorb heat, and the melt viscosity is low, and the drill cuttings are not easy to adhere; solid-gas Phase change materials absorb heat during solid-gas phase change, and no melt is produced, thus avoiding the adhesion of drill cuttings. The phase change temperature of mono- and binary-type layered perovskite solid-solid phase change materials is 60-105°C, and the phase change enthalpy is 67-115 J / g. There is no phase change during the phase change endothermic process, and the volume change is small, thus ensuring the flatness of the membrane surface and no melt is produced, thus avoiding the adhesion of drill cuttings. The above three types of phase change materials are reasonably matched, which not only achieves a better heat dissipation effect, but also reduces the risks of plugging, wire winding, and debris. The present invention adopts TCPVA to replace traditional resin emulsion to play the role of bonding and film formation. The brittleness of the film after formation is greater than that of traditional resin emulsion. When it is properly matched with soft fillers, the brittleness of the film layer is further increased. When the drill bit is cutting, the drill cuttings are discharged in the form of powder, which is beneficial to the prevention of wire winding and plugging. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The present invention is a flow chart of a method for preparing a heat dissipation coated aluminum sheet for drilling high-frequency, high-speed, and high-layer boards.

[0028] Figure 2 Result diagram of comparative test on drilling performance of adhesive-coated aluminum-based cover plates prepared in Examples 1 and 2 and prior art. DETAILED DESCRIPTION

[0029] The present invention provides a heat-dissipating coated aluminum sheet for high-frequency, high-speed, and multi-layer board drilling, and a method for preparing the same. To clarify the objectives, technical solutions, and effects of the present invention, the present invention is described in further detail below. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention.

[0030] The present invention provides a heat-dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, which includes an aluminum foil substrate and a composite water-soluble polymer resin layer coated on the upper surface of the aluminum foil substrate. The materials for preparing the composite water-soluble polymer resin layer include thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, solid-solid phase change material, solid-gas phase change material, solid-liquid phase change material, filler, lubricating material and additives.

[0031] Specifically, the heat-dissipating coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling provided by the present invention adopts thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol (TCPVA) instead of traditional resin emulsions and ordinary PVA and other materials as the main bonding resin. It has better water solubility, storage stability, and melt fluidity, and the melt viscosity decreases with the increase of the drill bit shear rate, and has typical shear thinning behavior. During the drilling process, as the temperature of the drilling area increases, the component undergoes solid-liquid phase change and absorbs heat, and the viscosity of the melted resin decreases with the increase of the drill bit shear rate, reducing the adhesion of drill cuttings to the drill bit, aluminum sheet, holes, etc., and also plays a certain lubricating role on the drill bit, extending the life of the drill bit. After film formation, it is fully water-soluble, which is convenient for the removal of drill cuttings in the holes in the client's later water washing process.

[0032] The present invention uses a combination of three types of phase change materials to achieve drill bit temperature reduction. Among them, TCPVA and solid-liquid phase change materials undergo solid-liquid phase change and absorb heat, and the melt viscosity is low, so drill cuttings are not easy to adhere. The solid-gas phase change material undergoes solid-gas phase change and absorbs heat, but does not produce melt, thus avoiding the adhesion of drill cuttings. The mono- and binary layered perovskite solid-solid phase change materials have a phase change temperature of 60-105°C and a phase change enthalpy of 67-115 J / g. There is no phase change during the phase change endothermic process, and the volume change is small, which ensures the flatness of the film surface and does not produce melt, thus avoiding the adhesion of drill cuttings. The above three types of phase change materials are reasonably matched, which not only achieves a good heat dissipation effect, but also reduces the risks of hole plugging, wire winding, and debris. The present invention uses TCPVA to replace traditional resin emulsions to play a bonding and film-forming role. The brittleness of the film after formation is greater than that of traditional resin emulsions. When appropriately matched with soft fillers, the brittleness of the film layer is further increased. When the drill bit cuts, the drill cuttings are discharged in the form of powder, which is beneficial to prevent wire winding and hole plugging.

[0033] The reasonable combination of the above materials in the composite water-soluble polymer resin layer of the present invention can significantly reduce the drilling temperature, which is beneficial to the improvement of CPK, reduces the risks of hole plugging, debris, wire entanglement, and needle breakage, and the film layer can be completely soluble in water, which is convenient for the removal of drill chips in the hole in the later stage, and is suitable for drilling high-frequency and high-speed boards.

[0034] In some embodiments, the solid-liquid phase change material is one or both of polyvinyl pyrrolidone and low molecular weight polyethylene glycol. Polyvinyl pyrrolidone is preferred as the solid-liquid phase change material. Polyvinyl pyrrolidone has excellent water solubility, adhesion, and film-forming properties, can improve the brittleness of the film system, reduce the risk of plugging, absorb heat during hot melting, and provide a certain lubrication effect on the drill bit.

[0035] In some embodiments, the solid-solid phase change material is (C n H 2n+1 NH3)2MX4 layered perovskite material, wherein n=8-18, M is a divalent metal, and X is a halogen atom. In this embodiment, the solid-solid phase change material is (C 12 H 25 NH3)2ZnCl4、(C 10 H 21 NH3)2ZnCl4、(C 10 H 21 NH3)2CoCl4、(C 12 H 25 NH3)2CoCl4、(C 10 H 21 NH3)2CoCl4-(C 16 H 33 NH3)2CoCl4、(C 12 H25 NH3)2CoCl4-(C 16 H 33 NH3)2CoCl4、(C 10 H 21 NH3)2ZnCl4-(C 16 H 33 NH3)2ZnCl4、(C 12 H 25 NH3)2ZnCl4-(C 16 H 33 Mono- and binary layered perovskite materials such as NH3)2ZnCl4 have a phase change temperature of 60-105°C and a phase change enthalpy of 67-115 J / g. During the phase change, they absorb the heat generated during the drilling process by transforming the crystal structure. There is no phase change during the transformation process, and the volume change is small, which ensures the flatness of the membrane surface and does not have the disadvantage of solid-liquid phase change materials that are prone to adherence to drill cuttings, reducing the risks of wire entanglement and debris.

[0036] In some embodiments, the solid-gas phase change material is one or both of sublimed salicylic acid and 2,4,6-triisopropyl-1,3,5-trioxane. In this embodiment, the solid-gas phase change material does not readily sublime during storage at room temperature, but rapidly sublimates under local high-temperature conditions within the drilling process, effectively reducing drilling temperature while preventing the formation of a high-viscosity melt and avoiding risks such as entanglement and debris.

[0037] In some embodiments, the filler is one or more of talc, calcium carbonate, barium sulfate, calcined kaolin, mica powder, bentonite, and silica. In this embodiment, a slightly softer material is preferred as the filler, as it can increase the brittleness of the membrane layer and reduce its hardness, thereby improving CPK and preventing plugging.

[0038] In some embodiments, the lubricating material is one or both of a wax emulsion and nonylphenol polyoxyethylene ether. In this embodiment, the lubricating material not only provides lubrication for the drill bit but also floats to the surface of the film during film formation and drying, providing a good anti-sticking effect and reducing the risk of debris.

[0039] In some embodiments, the auxiliary agent is one or more of a leveling agent, a film auxiliary agent, a dispersant, and a defoaming agent, but is not limited thereto.

[0040] In some embodiments, the thickness of the aluminum foil substrate is 70-250 μm, and the thickness of the composite water-soluble polymer resin layer is 20-100 μm, but is not limited thereto.

[0041] In some embodiments, a method for preparing a heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to the present invention is also provided. Figure 1 As shown, it includes the steps of:

[0042] S10, pre-preparing thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol;

[0043] S20, adding the thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol into hot water for dissolution, and then adding a solid-liquid phase change material and stirring to obtain a solid-liquid phase change mixed material solution;

[0044] 30. Add the dispersant to water and stir evenly, then add the solid-solid phase change material and filler, stir evenly and grind to obtain a solid-solid phase change mixed material solution;

[0045] S40, dissolving the solid-gas phase change material into the ethanol solution to obtain a solid-gas phase change mixed material solution;

[0046] S50, gradually adding the solid-gas phase change mixed material solution and the solid-solid phase change mixed material solution to the solid-liquid phase change mixed material solution, and adding a lubricating material, a leveling agent, a defoaming agent, and a membrane auxiliary agent, stirring evenly, filtering, and vacuuming to defoam, to obtain a mixed glue solution;

[0047] S60, coating the mixed adhesive on the surface of the aluminum foil substrate, and drying to obtain the heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling.

[0048] In the present invention, the steps of preparing thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol include: adding methanol and vinyl acetate into a reaction container, stirring evenly under a nitrogen atmosphere, heating the reaction container to 60-70°C, adding AIBN to initiate a reaction, then dropwise adding acrylic acid in an amount of 1%-5% of the amount of vinyl acetate, continuing the reaction for 5-8 hours, and after the reaction is completed, precipitating, filtering, and drying the copolymer solution; preparing the copolymer into a methanol solution, adding a NaOH methanol solution, and performing an alcoholysis reaction at 50-70°C. After the reaction is completed for 1-2 hours, the copolymer is subjected to impurity removal, filtering, and drying to obtain carboxyl-containing PVA; and adding the carboxyl-containing PVA and glycerol in a proportioned manner into a twin-screw extruder, and plasticizing and shearing to obtain thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, i.e., TCPVA resin. The preparation method of the heat dissipation coated aluminum sheet for drilling high-frequency, high-speed and high-layer boards provided by the present invention is simple and easy to operate, and the prepared coated aluminum sheet can significantly reduce the drilling temperature, which is beneficial to the improvement of CPK, reduces the risks of hole plugging, debris, wire entanglement and needle breakage, and the film layer can be completely soluble in water, which is convenient for cleaning the drill chips in the hole in the later stage, and is suitable for drilling high-frequency, high-speed and high-layer boards.

[0049] The present invention will be further explained below by means of specific embodiments:

[0050] Example 1

[0051] A method for preparing a heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, comprising the following steps:

[0052] (1) A certain amount of methanol and 30% vinyl acetate were added to a reaction vessel, and the mixture was stirred evenly under a nitrogen atmosphere. The temperature of the reaction vessel was raised to about 60°C, and 0.1% molar fraction of AIBN was added to initiate the reaction. Acrylic acid at 1% molar fraction of the vinyl acetate was then added dropwise. The reaction was continued for 5 hours. After the reaction was completed, the copolymer solution was precipitated, filtered, and dried to obtain poly(vinyl acetate-co-acrylic acid).

[0053] (2) The copolymer obtained above was prepared into a 30% by mass methanol solution, and a 0.03% by mole fraction of vinyl acetate NaOH methanol solution was added to carry out alcoholysis reaction at a temperature of about 60°C. After the reaction was completed for 1 hour, the carboxyl-containing PVA (CPVA) was obtained by impurity removal, filtration, and drying.

[0054] (3) CPVA and GL were added into a twin-screw extruder at a mass ratio of 75:25, and TCPVA resin was obtained through plasticization and shearing.

[0055] (4) Take 20 parts of TCPVA resin and dissolve it in 60 parts of 70°C hot water in advance.

[0056] (5) Add 5 parts of polyvinyl pyrrolidone to (4) and stir until completely dissolved.

[0057] (6) Take another 20 parts of water, add 0.6 parts of dispersant, stir evenly, and add 1 part of (C 12 H 25 NH3)2ZnCl4, 1 part (C 12 H 25 NH3)2CoCl4, 1 part C 10 H 21 NH3)2CoCl4-(C 16 H 33 NH3)2CoCl4, 1 part (C 10 H 21 NH3)2ZnCl4-(C 16 H 33 NH3)2ZnCl4, 6 parts of talc, 4 parts of calcium carbonate, 3 parts of barium sulfate, 1 part of calcined kaolin, 1 part of mica powder, 0.2 parts of bentonite, and 0.3g of silicon dioxide were dispersed and stirred at high speed for 1 hour, and then ground with a sand mill until the scraper fineness was less than 30μm.

[0058] (7) Take 2 parts of ethanol solution and dissolve 1 part of sublimed salicylic acid.

[0059] (8) Gradually add the solutions in (6) and (7) to the solution in (5), and add 0.5 parts of polyethylene wax emulsion, 0.6 parts of leveling agent, 0.3 parts of defoaming agent, and 1 part of film-forming aid. After high-speed dispersion and stirring for 2 hours, pass through a homogenizer and a disperser once each, continue stirring for 2 hours, filter, vacuum and defoam, and set aside.

[0060] (9) The above-mentioned glue solution is coated on the surface of aluminum foil with a thickness of 0.12 mm by a coating machine, and the coating thickness is 60 μm. The oven temperature is set to increase gradually from 90-150°C (PVA system is prone to blistering when baked at high temperature. After baking at medium and low temperature until the surface is dry, it is placed in the high temperature zone and baked until it is completely dry). The fully water-soluble heat-dissipating coated aluminum sheet 1 is obtained.

[0061] Example 2

[0062] A method for preparing a heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, comprising the following steps:

[0063] (1) A certain amount of methanol was added to a reaction vessel, and vinyl acetate (35% of the methanol) was added. The mixture was stirred evenly under a nitrogen atmosphere. The temperature of the reaction vessel was raised to about 70°C, and 0.1% of the monomer molar fraction of AIBN was added to initiate the reaction. Acrylic acid (1% of the vinyl acetate) was then added dropwise. The reaction was continued for 5 hours. After the reaction was completed, the copolymer solution was precipitated, filtered, and dried to obtain poly(vinyl acetate-co-acrylic acid).

[0064] (2) The copolymer obtained above was prepared into a 30% by mass methanol solution, and a 0.03% by mole fraction of vinyl acetate NaOH methanol solution was added to carry out alcoholysis reaction at a temperature of about 60°C. After the reaction was completed for 1 hour, the carboxyl-containing PVA (CPVA) was obtained by impurity removal, filtration, and drying.

[0065] (3) CPVA and GL were added into a twin-screw extruder at a mass ratio of 65:35, and TCPVA resin was obtained through plasticization and shearing.

[0066] (4) Take 18 parts of TCPVA resin and dissolve it in 60 parts of 70°C hot water in advance.

[0067] (5) Add 7 parts of polyvinyl pyrrolidone to (4) and stir until completely dissolved.

[0068] (6) Take another 20 parts of water, add 0.6 parts of dispersant, stir evenly, and add 1 part of (C 10 H 21 NH3)2ZnCl4, 1 part (C 10 H 21 NH3)2CoCl4, 1 part (C 12 H 25NH3)2CoCl4-(C 16 H 33 NH3)2CoCl4, 1 part (C 12 H 25 NH3)2ZnCl4-(C 16 H 33 NH3)2ZnCl4, 4 parts of talc, 6 parts of calcium carbonate, 2 parts of barium sulfate, 1 part of calcined kaolin, 1 part of mica powder, 0.2 parts of bentonite, and 0.3 parts of silicon dioxide, disperse and stir at high speed for 1 hour, and grind in a sand mill until the scraper fineness is less than 30μm.

[0069] (7) Take 2 parts of ethanol solution and dissolve 1 part of sublimed salicylic acid.

[0070] (8) Gradually add the solutions in (6) and (7) to the solution in (5), and add 0.5 parts of wax emulsion, 0.6 parts of leveling agent, 0.3 parts of defoaming agent, and 1 part of film-forming aid. After high-speed dispersion and stirring for 2 hours, pass through a homogenizer and a disperser once each, continue stirring for 2 hours, filter, vacuum and defoam, and set aside.

[0071] (9) The above-mentioned glue solution is coated on the surface of aluminum foil with a thickness of 0.12 mm by a coating machine, and the coating thickness is 60 μm. The oven temperature is set to increase gradually from 90-150°C (PVA system is prone to blistering when baked at high temperature. After baking at medium and low temperature until the surface is dry, it is placed in the high temperature zone and baked until it is completely dry). The fully water-soluble heat-dissipating coated aluminum sheet 2 is obtained.

[0072] The drilling performance comparison test of the adhesive coated aluminum base cover plate prepared in Examples 1 and 2 and the prior art was carried out. A high-layer board product of a well-known domestic copper clad laminate factory was selected as the research object. The drilling performance of 0.2mm hole diameter was tested and the temperature of the drilling area was measured using infrared temperature measuring equipment. The test results are as follows: Figure 2 As shown. Figure 2 The test results show that the fully water-soluble heat-dissipating coated aluminum sheet prepared in Examples 1 and 2 helps to dissipate heat from the substrate, improve drilling accuracy and hole wall quality, extend the life of the drill bit, and has no quality risks such as wire entanglement, hole plugging, and debris. The drill chips in the hole can be easily removed through the client water washing process, which can meet the drilling needs of high-frequency, high-speed, and high-layer boards.

[0073] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling, characterized in that: The invention comprises an aluminum foil substrate and a composite water-soluble polymer resin layer coated on the upper surface of the aluminum foil substrate, wherein the composite water-soluble polymer resin layer is prepared from materials including thermoplastic carboxyl monomer copolymerized modified polyvinyl alcohol, solid-solid phase change material, solid-gas phase change material, solid-liquid phase change material, filler, lubricant and additive; The solid-solid phase change material is (C n H 2n+1 NH3)2MX4 layered perovskite materials, wherein n=8-18, M is a divalent metal, and X is a halogen atom; The solid-gas phase change material is one or two of sublimed salicylic acid and 2,4,6-triisopropyl-1,3,5-trioxane; The solid-liquid phase change material is one or both of polyvinyl pyrrolidone and low molecular weight polyethylene glycol.

2. The heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to claim 1, characterized in that: The filler is one or more of talc, calcium carbonate, barium sulfate, calcined kaolin, mica powder, bentonite and silicon dioxide.

3. The heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to claim 1, characterized in that: The lubricating material is one or both of wax emulsion and nonylphenol polyoxyethylene ether.

4. The heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to claim 1, characterized in that: The auxiliary agent is one or more of a leveling agent, a film auxiliary agent, a dispersant and a defoaming agent.

5. The heat dissipation coated aluminum sheet for high frequency, high speed and high multilayer board drilling according to claim 1, characterized in that: The thickness of the aluminum foil substrate is 70-250 μm, and the thickness of the composite water-soluble polymer resin layer is 20-100 μm.

6. A method for preparing a heat dissipation coated aluminum sheet for high-frequency, high-speed, and high-layer board drilling according to any one of claims 1 to 5, characterized in that: Including steps: Preparing thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol in advance; Adding the thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol into hot water to dissolve it, then adding the solid-liquid phase change material and stirring to obtain a solid-liquid phase change mixed material solution; After adding the dispersant into water and stirring evenly, the solid-solid phase change material and filler are added, stirred evenly, and then ground to obtain a solid-solid phase change mixed material solution; dissolving a solid-gas phase change material into an ethanol solution to obtain a solid-gas phase change mixed material solution; Gradually adding the solid-gas phase change mixed material solution and the solid-solid phase change mixed material solution into the solid-liquid phase change mixed material solution, and adding a lubricating material, a leveling agent, a defoaming agent and a membrane aid, stirring evenly, filtering and vacuuming to defoam, to obtain a mixed glue solution; The mixed adhesive solution is coated on the surface of an aluminum foil substrate, and after drying, the heat dissipation coated aluminum sheet for drilling high-frequency, high-speed, and high-layer boards is obtained.

7. The method for preparing the heat dissipation coated aluminum sheet for high-frequency, high-speed and high-layer board drilling according to claim 6, characterized in that: The steps of preparing thermoplastic carboxyl monomer copolymer modified polyvinyl alcohol include: Methanol and vinyl acetate were added to a reaction vessel and stirred evenly under a nitrogen atmosphere. The temperature of the reaction vessel was raised to 60-70°C, and AIBN was added to initiate the reaction. Acrylic acid (1%-5% of the amount of vinyl acetate) was then added dropwise. The reaction was continued for 5-8 hours. After the reaction was completed, the copolymer solution was precipitated, filtered, and dried. The copolymer is prepared into a methanol solution and a NaOH methanol solution is added to perform alcoholysis at 50-70° C. After the reaction is completed for 1-2 hours, the carboxyl-containing PVA is obtained by removing impurities, filtering, and drying; The carboxyl-containing PVA and glycerol are added into a twin-screw extruder in a certain proportion, and thermoplastic carboxyl monomer copolymer-modified polyvinyl alcohol, namely TCPVA resin, is obtained through plasticization and shearing.

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