Preparation method of flexible PCB aluminum substrate material capable of being bent and shaped at will

Abstract

The invention relates to the field of circuit boards, in particular to a preparation method of a flexible PCB aluminum substrate material capable of being bent and shaped at will. The prepared flexible PCB aluminum substrate is ingenious and reasonable in structural design, the aluminum plate and the copper foil are combined through the heat-conducting glue, so that the flexible PCB aluminum substrate has good flexibility, is not prone to breakage, can be bent at will, and can meet the requirements for diversified modeling and all-dimensional lighting of LED lamps, heat generated by the LED lamps can be rapidly conducted to the aluminum substrate through the heat-conducting glue, and the service life of the LED lamps is prolonged. Therefore, the purpose of rapid heat dissipation is achieved, and the heat dissipation effect is good.

Description

Technical Field

[0001] The present invention relates to the field of circuit boards, and in particular to a method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped. Background Art

[0002] In recent years, LED light sources have been widely used in many fields due to their significant advantages such as long life, high luminous efficiency, low radiation and low power consumption.

[0003] LED light sources generate a lot of heat while providing high brightness output. Therefore, in a high temperature working environment, LEDs may suffer from color deviation, reduced brightness, shortened service life, and even immediate failure. To avoid the above problems, LED light sources are required to be able to promptly and fully conduct the heat generated when the light source is working. In current technology, printed circuit boards (PCBs) are commonly used to carry LED light sources to meet the requirements for thermal conductivity.

[0004] Printed circuit boards (PCBs) are the support for electronic components and realize electrical connections between electronic components. The quality of their manufacturing and processing is very important and directly related to the cost and quality of the entire electronic product, and even affects the success or failure of the entire business competition. However, the heat dissipation performance of existing PCB aluminum substrate materials is still insufficient, and they cannot be bent or curved. The thermal conductive adhesive is not flexible and is easy to break. Therefore, it is difficult to solve the problem of LED light sources achieving all-round lighting and designing various shapes. At the same time, there are certain limitations on improving their heat dissipation efficiency. Summary of the invention

[0005] In view of the problems existing in the prior art, the object of the present invention is to provide a flexible aluminum substrate material which can be bent arbitrarily and has good heat dissipation effect.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped, comprising the following steps:

[0008] Step 1: Prepare suitable aluminum plates and copper foils in advance and keep the surfaces clean;

[0009] Step 2, preparing a thermal conductive adhesive, the components of the thermal conductive adhesive are calculated by weight and include:

[0010] 22-35 parts of carboxyl-terminated nitrile rubber, 45-56 parts of epoxy resin, 8-12 parts of acrylic resin, 4-6.2 parts of polyvinyl butyral resin, 8.4-16.8 parts of thermally conductive modified filler, 1.5-2.6 parts of curing agent and 16-45 parts of solvent;

[0011] Step 3, evenly coating the thermal conductive adhesive on the surface of the aluminum plate, and baking to form a thermal conductive adhesive layer;

[0012] Step 4, pressing the rolled copper foil onto the thermal conductive adhesive layer, and then subjecting it to aging treatment, to obtain a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily.

[0013] Preferably, in step 1, the aluminum plate is a full series aluminum plate, among which O-state aluminum has better flexibility.

[0014] Preferably, in step 2, the weight average molecular weight of the carboxyl-terminated nitrile rubber is 100,000-120,000, the carboxyl content is 2-6wt%, and the acrylonitrile content is 30-40wt%.

[0015] Preferably, in step 2, the thermally conductive modified filler includes modified tungsten diboride powder, alumina powder (spherical, rhombic) and aluminum nitride powder, and the mass ratio of the modified tungsten diboride powder, alumina powder and aluminum nitride powder is 5:0.1-1:0.1-1.

[0016] Preferably, in step 2, the epoxy resin type is one or more combinations of E-42, E-44, and E-51.

[0017] Preferably, in step 2, the density of the acrylic resin is 0.94 g / cm 3 , acid value is 3mg KOH / g, solid content is 55%±1%, viscosity is 5×10 4 mpa·s(25℃).

[0018] Preferably, in step 2, the number average molecular weight of the polyvinyl butyral resin is 160,000-200,000, the degree of acetalization is 72%-86%, and the content of vinyl alcohol groups is 16-20wt%.

[0019] Preferably, in step 2, the curing agent is one or more combinations of ethylenediamine, isophoronediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0020] Preferably, in step 2, the solvent is one or more combinations of ethyl acetate, propyl acetate, butyl acetate, toluene, methyl ethyl ketone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0021] Preferably, in step 2, the method for preparing the modified tungsten diboride powder comprises:

[0022] S1. Weigh 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 4-vinylbenzaldehyde and add them to 1,4-dioxane. After stirring evenly, introduce inert gas to replace the air, then dropwise add an acidic catalyst, heat to 95-115°C, keep stirring for 12-36h, after the reaction is completed, cool to room temperature, then remove the solvent under reduced pressure, wash the product with alcohol for at least three times, and dry to obtain a modifier VBA-TZ;

[0023] S2, mix the tungsten diboride powder WB2 and the ethanol solution, and after uniform dispersion, add γ-mercaptopropyltriethoxysilane, and reflux and stir for 6-12 hours at 60-80°C. After the treatment, filter and extract the residue, wash it with alcohol three times, and dry it to obtain the mercaptolated tungsten diboride powder HS-WB2;

[0024] S3. Mix the modifier VBA-TZ and N,N-dimethylformamide DMF, stir and disperse them evenly, then add HS-WB2 powder, introduce inert gas to replace the air, stir and react under the conditions of photosensitizer and ultraviolet light irradiation, the reaction time is 1.2-2.4h, after the reaction is completed, remove the solvent under reduced pressure, wash with alcohol three times, and dry to obtain modified tungsten diboride powder.

[0025] Preferably, in S1, the mass volume ratio of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine, 4-vinylbenzaldehyde and 1,4-dioxane is (2.1-4.2) g:(0.3-0.6) g:(20-60) mL.

[0026] Preferably, in S1, the acidic catalyst is glacial acetic acid, and the added amount is 1%-5% of the mass of 4-vinylbenzaldehyde.

[0027] Preferably, in S2, the particle size of the tungsten diboride powder is 5-10 μm, and the mass fraction of the ethanol solution is 30%-60%.

[0028] Preferably, in S2, the mass volume ratio of tungsten diboride powder, γ-mercaptopropyltriethoxysilane and ethanol solution is 1 g: (0.23-0.46) g: (15-35) mL.

[0029] Preferably, in S3, the mass volume ratio of the mercaptolated tungsten diboride powder, the modifier VBA-TZ and N,N-dimethylformamide is 1 g: (0.16-0.32) g: (20-40) mL.

[0030] Preferably, in S3, the ultraviolet light intensity is 280-560 mW / cm 2 The photosensitizer is benzoin dimethyl ether, and the added amount is 2.5%-7.5% of the mass of the modifier VBA-TZ.

[0031] Preferably, in step 2, the preparation process of the thermal conductive adhesive includes:

[0032] Weigh terminal carboxyl nitrile rubber, epoxy resin and acrylic resin, mix them in a solvent, and obtain a mixed solution after they are completely dissolved; add a curing agent, a thermally conductive modified filler and polyvinyl butyral into the mixed solution, and then disperse and stir them evenly to obtain a thermally conductive adhesive.

[0033] Preferably, in step 3, the thickness of the thermal conductive adhesive layer is 30-100 μm.

[0034] Preferably, in step 3, the baking temperature is 50-110° C., and the baking speed is 10-50 m / min.

[0035] Preferably, in step 4, the rolled copper foil is pressed onto the thermally conductive adhesive layer by a laminating machine, and the laminating operating temperature of the laminating machine is set to 100-130°C.

[0036] Preferably, in step 4, the aging process includes: performing an aging process in an oven with a working temperature set at 110-130° C. for 15-50 minutes, and then controlling the oven temperature to rise to 180-200° C. for aging for 15-50 minutes.

[0037] In a second aspect, the present invention provides a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily, which is prepared by the above-mentioned preparation method.

[0038] The beneficial effects of the present invention are:

[0039] 1. The structural design of the flexible PCB aluminum substrate prepared by the present invention is ingenious and reasonable. The aluminum plate and the copper foil are combined by thermal conductive adhesive, so that it has better flexibility, is not easy to break, can be bent arbitrarily, and can meet the diversified shapes of LED lamps and all-round lighting needs. In addition, the heat generated by the LED lamp can be quickly transferred to the aluminum substrate through the thermal conductive adhesive and quickly dissipated by the aluminum substrate, thereby achieving the purpose of rapid heat dissipation and having a good heat dissipation effect.

[0040] 2. Among the raw materials of the thermally conductive adhesive used in the present invention, a composite of terminal carboxyl nitrile rubber, epoxy resin and acrylic resin is used as the main material, polyvinyl butyral resin is used as a reinforcing agent, and the thermally conductive modified filler is a modified tungsten diboride and a small amount of aluminum compound. Among them, the purpose of the small amount of aluminum compound is to provide a certain stability and thermal conductivity. The modified tungsten diboride powder is prepared by using tungsten diboride powder as the base material, and after thiol modification, it undergoes a thiol-olefin click chemistry reaction with the modifier VBA-TZ containing an olefin group; the modifier VBA-TZ is prepared by using 4,4',4"-(1,3,5-triazine-2,4,6-triyl) triphenylamine and 4-vinylbenzaldehyde through an amine-aldehyde condensation reaction. The thermally conductive modified filler prepared by the present invention is an organic-inorganic composite material, which not only has good compatibility with the resin, but also has good thermal conductivity, and excellent strength and flexibility.

[0041] 3. In addition, since the rolled copper foil has good conductivity and high ductility, it can further improve the overall flexibility, good flexibility and long service life in terms of meeting the purpose of conductivity. In addition, the overall structure is simple and easy to implement, which is conducive to wide promotion and application. The method provided by the present invention has a simple process, can quickly produce aluminum materials that can be bent arbitrarily, greatly shortens the production cycle, improves production efficiency, and the entire production process is simple, easy to implement and effectively guarantees product quality. DETAILED DESCRIPTION

[0042] The technical solution of the present invention is described below through specific examples. It should be understood that the one or more method steps mentioned in the present invention do not exclude the existence of other method steps before and after the combination step or the insertion of other method steps between these explicitly mentioned steps; it should also be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. Moreover, unless otherwise specified, the numbering of each method step is only a convenient tool for identifying each method step, and is not intended to limit the order of arrangement of each method step or to limit the scope of the present invention. The change or adjustment of the relative relationship thereof shall also be regarded as the scope of the present invention without substantially changing the technical content.

[0043] In order to better understand the above technical scheme, the exemplary embodiments of the present invention are described in more detail below. Although exemplary embodiments of the present invention are shown, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to enable the scope of the present invention to be fully communicated to those skilled in the art.

[0044] The present invention will be further described below in conjunction with the following examples.

[0045] Example 1

[0046] An aluminum substrate material that can be bent and shaped arbitrarily includes an aluminum plate, a thermally conductive adhesive and a rolled copper foil, wherein the rolled copper foil is bonded to the aluminum plate through the thermally conductive adhesive. The components of the thermally conductive adhesive are calculated by weight and include:

[0047] 28 parts of terminal carboxyl nitrile rubber, 55 parts of epoxy resin, 9 parts of acrylic resin, 4.7 parts of polyvinyl butyral resin, 9.5 parts of modified tungsten diboride powder, 1 part of alumina powder, 0.9 parts of aluminum nitride powder, 1.8 parts of isophorone diamine and 32 parts of methyl ethyl ketone.

[0048] Among them, the weight average molecular weight of the carboxyl-terminated nitrile rubber is 110,000, the carboxyl content is 4wt%, and the acrylonitrile content is 35wt%; the model of the epoxy resin is E-44; the density of the acrylic resin is 0.94g / cm 3 , acid value is 3mg KOH / g, solid content is 55%±1%, viscosity is 5×10 4 mpa·s (25°C); the number average molecular weight of the polyvinyl butyral resin is 180,000, the acetal degree is 78%, and the content of vinyl alcohol groups is 18wt%.

[0049] The preparation method of modified tungsten diboride powder includes:

[0050] S1. Weigh 3.1 g of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 0.4 g of 4-vinylbenzaldehyde and add them into 40 mL of 1,4-dioxane. After stirring thoroughly, introduce inert gas to replace the air, then dropwise add glacial acetic acid in an amount of 3% of the mass of 4-vinylbenzaldehyde, heat to 105°C, keep stirring for 24 hours, cool to room temperature after the reaction is completed, remove the solvent under reduced pressure, wash the product with alcohol for at least three times, and dry to obtain the modifier VBA-TZ;

[0051] S2, 1g of tungsten diboride powder (WB2, Φ = 5-10μm) and 25mL of 40wt% ethanol solution were mixed, and after being evenly dispersed, 0.35g of γ-mercaptopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 70°C for 10h. After the treatment, the residue was filtered and extracted, washed with alcohol three times, and dried to obtain mercaptolated tungsten diboride powder HS-WB2;

[0052] S3, 0.24g modifier VBA-TZ and 30mL N,N-dimethylformamide DMF were mixed, stirred and dispersed evenly, 1g HS-WB2 powder was added, inert gas was introduced to replace the air, and photosensitizer benzoin dimethyl ether was added in an amount of 5.5% of the mass of the modifier VBA-TZ. Under a light intensity of 420mW / cm 2The reaction was stirred for 1.8 hours under ultraviolet light irradiation. After the reaction was completed, the solvent was removed under reduced pressure, and the product was washed with alcohol three times and dried to obtain modified tungsten diboride powder.

[0053] The preparation of the above-mentioned aluminum substrate material that can be bent and shaped arbitrarily comprises the following steps:

[0054] Step (1), preparing an aluminum plate and a copper foil of O-state aluminum;

[0055] Step (2), preparing thermal conductive adhesive:

[0056] (2.1) Prepare raw materials: The weight proportions of raw materials are: 28 parts of carboxyl-terminated nitrile rubber, 55 parts of epoxy resin, 9 parts of acrylic resin, 1.8 parts of isophorone diamine, 9.5 parts of modified tungsten diboride powder, 1 part of alumina powder, 0.9 parts of aluminum nitride powder, 4.7 parts of polyvinyl butyral, and 32 parts of methyl ethyl ketone;

[0057] (2.2) Dissolving: using methyl ethyl ketone to completely dissolve the carboxyl-terminated nitrile rubber, epoxy resin, and acrylic resin to obtain a mixed solution;

[0058] (2.3) Mixing: adding isophorone diamine, modified tungsten diboride powder, alumina powder, aluminum nitride powder and polyvinyl butyral to the mixed solution, and then dispersing and stirring the mixture to obtain a thermally conductive adhesive. The dispersing and stirring time is 1.5 hours at a temperature of 30° C.

[0059] Step (3), preparing a thermally conductive adhesive layer:

[0060] (3.1) Coating: The thermal conductive adhesive is evenly coated on one surface of the aluminum plate by a coating machine, and the thickness of the thermal conductive adhesive layer is 75 μm;

[0061] (3.2) Baking: The thermal conductive adhesive layer is then baked at a temperature of 85° C. and a baking speed of 25 m / min to form a thermal conductive adhesive layer.

[0062] Step (4), preparing an aluminum substrate material that can be bent arbitrarily:

[0063] (4.1) The rolled copper foil is laminated and pressed onto the thermal conductive adhesive layer by a laminating machine, and the laminating working temperature of the laminating machine is set to 115 degrees;

[0064] (4.2) Push the sample into an oven set at 120°C for aging for 25 minutes, then control the oven temperature to 200°C for aging for 30 minutes.

[0065] There is no order of precedence for steps (1) and (2).

[0066] Example 2

[0067] An aluminum substrate material that can be bent and shaped arbitrarily is different from Example 1 in that the preparation method is slightly different. Specifically, the preparation method includes the following steps:

[0068] Step (1), preparing an aluminum plate and a copper foil of O-state aluminum;

[0069] Step (2), preparing thermal conductive adhesive:

[0070] (2.1) Prepare raw materials: The weight proportions of raw materials are: 22 parts of carboxyl-terminated nitrile rubber, 45 parts of epoxy resin E-424, 8 parts of acrylic resin, 1.8 parts of diethylenetriamine, 7 parts of modified tungsten diboride powder, 0.7 parts of alumina powder, 0.7 parts of aluminum nitride powder, 4 parts of polyvinyl butyral, and 16 parts of ethyl acetate;

[0071] (2.2) Dissolving: using ethyl acetate to completely dissolve the carboxyl-terminated nitrile rubber, epoxy resin E-42, and acrylic resin to obtain a mixed solution;

[0072] (2.3) Mixing: adding diethylenetriamine, modified tungsten diboride powder, alumina powder, aluminum nitride powder and polyvinyl butyral to the mixed solution, and then dispersing and stirring the mixture to obtain a thermal conductive adhesive. The dispersing and stirring time is 1 hour at a temperature of 20° C.

[0073] Step (3), preparing a thermally conductive adhesive layer:

[0074] (3.1) Coating: The thermal conductive adhesive is evenly coated on one surface of the aluminum plate by a coating machine, and the thickness of the thermal conductive adhesive layer is 30 μm;

[0075] (3.2) Baking: The thermal conductive adhesive layer is then baked at a temperature of 50° C. and a baking speed of 10 m / min to form a thermal conductive adhesive layer.

[0076] Step (4), preparing an aluminum substrate material that can be bent arbitrarily:

[0077] (4.1) Laminating the rolled copper foil onto the thermal conductive adhesive layer using a laminating machine, and setting the laminating working temperature of the laminating machine to 100 degrees;

[0078] (4.2) Push the sample into an oven set at 110°C for aging for 15 minutes, then control the oven temperature to 180°C for aging for 15 minutes.

[0079] There is no order of precedence for steps (1) and (2).

[0080] Example 3

[0081] An aluminum substrate material that can be bent and shaped arbitrarily is different from Example 1 in that the preparation method is slightly different. Specifically, the preparation method includes the following steps:

[0082] Step (1), preparing an aluminum plate and a copper foil of O-state aluminum;

[0083] Step (2), preparing thermal conductive adhesive:

[0084] (2.1) Prepare raw materials: The weight proportions of raw materials are: 35 parts of carboxyl-terminated nitrile rubber, 56 parts of epoxy resin E-51, 12 parts of acrylic resin, 2.6 parts of ethylenediamine, 14 parts of modified tungsten diboride powder, 1.6 parts of alumina powder, 1.2 parts of aluminum nitride powder, 6.2 parts of polyvinyl butyral, and 45 parts of toluene;

[0085] (2.2) Dissolving: using toluene to completely dissolve the carboxyl-terminated nitrile rubber, epoxy resin E-51, and acrylic resin to obtain a mixed solution;

[0086] (2.3) Mixing: Add ethylenediamine, modified tungsten diboride powder, alumina powder, aluminum nitride powder and polyvinyl butyral into the mixed solution, and then disperse and stir them evenly. The dispersion and stirring time is 2 hours at a temperature of 40° C. to obtain a thermal conductive adhesive.

[0087] Step (3), preparing a thermally conductive adhesive layer:

[0088] (3.1) Coating: The thermal conductive adhesive is evenly coated on one surface of the aluminum plate by a coating machine, and the thickness of the thermal conductive adhesive layer is 100 μm;

[0089] (3.2) Baking: The thermal conductive adhesive layer is then baked at a temperature of 110° C. and a baking speed of 50 m / min to form a thermal conductive adhesive layer.

[0090] Step (4), preparing an aluminum substrate material that can be bent arbitrarily:

[0091] (4.1) The rolled copper foil is laminated and pressed onto the thermal conductive adhesive layer by a laminating machine, and the laminating working temperature of the laminating machine is set to 130 degrees;

[0092] (4.2) Push the sample into an oven set at 130°C for aging for 50 minutes, then control the oven temperature to 200°C for aging for 50 minutes.

[0093] There is no order of precedence for steps (1) and (2).

[0094] Example 4

[0095] An aluminum substrate material that can be bent and shaped arbitrarily is different from Example 1 only in that the preparation method of the modified tungsten diboride powder in the thermal conductive adhesive raw material is slightly different.

[0096] The preparation method of modified tungsten diboride powder comprises:

[0097] S1. Weigh 2.1 g of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 0.3 g of 4-vinylbenzaldehyde and add them into 20 mL of 1,4-dioxane. After stirring thoroughly, introduce inert gas to replace the air, then dropwise add glacial acetic acid in an amount of 1% of the mass of 4-vinylbenzaldehyde, heat to 95°C, keep stirring for 12 hours, cool to room temperature after the reaction is completed, remove the solvent under reduced pressure, wash the product with alcohol for at least three times, and dry to obtain the modifier VBA-TZ;

[0098] S2, 1g of tungsten diboride powder (WB2, Φ = 5-10μm) and 15mL of 30wt% ethanol solution were mixed and dispersed evenly, and then 0.23g of γ-mercaptopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 60°C for 6h. After the treatment, the residue was filtered and extracted, washed with alcohol three times, and dried to obtain mercaptolated tungsten diboride powder HS-WB2;

[0099] S3, 0.16g modifier VBA-TZ and 20mL DMF were mixed, stirred and dispersed evenly, 1g HS-WB2 powder was added, inert gas was introduced to replace the air, and photosensitizer benzoin dimethyl ether was added in an amount of 2.5% of the mass of modifier VBA-TZ. Under a light intensity of 280mW / cm 2 The reaction was stirred for 1.2 hours under ultraviolet light irradiation. After the reaction was completed, the solvent was removed under reduced pressure, and the product was washed with alcohol three times and dried to obtain modified tungsten diboride powder.

[0100] Example 5

[0101] An aluminum substrate material that can be bent and shaped arbitrarily is different from Example 1 only in that the preparation method of the modified tungsten diboride powder in the thermal conductive adhesive raw material is slightly different.

[0102] The preparation method of modified tungsten diboride powder comprises:

[0103] S1. Weigh 4.2 g of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 0.6 g of 4-vinylbenzaldehyde and add them into 60 mL of 1,4-dioxane. After stirring evenly, introduce inert gas to replace the air, then dropwise add glacial acetic acid in an amount of 5% of the mass of 4-vinylbenzaldehyde, heat to 115°C, keep stirring for 36 hours, cool to room temperature after the reaction is completed, remove the solvent under reduced pressure, wash the product with alcohol for at least three times, and dry to obtain the modifier VBA-TZ;

[0104] S2, 1g of tungsten diboride powder (WB2, Φ = 5-10μm) and 35mL of 60wt% ethanol solution were mixed and dispersed evenly, and then 0.46g of γ-mercaptopropyltriethoxysilane was added, and the mixture was refluxed and stirred at 80°C for 12h. After the treatment, the residue was filtered and extracted, washed with alcohol three times, and dried to obtain mercaptolated tungsten diboride powder HS-WB2;

[0105] S3, 0.32g modifier VBA-TZ and 40mL N,N-dimethylformamide DMF were mixed, stirred and dispersed evenly, 1g HS-WB2 powder was added, inert gas was introduced to replace the air, and photosensitizer benzoin dimethyl ether was added in an amount of 7.5% of the mass of the modifier VBA-TZ. Under a light intensity of 560mW / cm 2 The reaction was stirred for 2.4 hours under ultraviolet light irradiation. After the reaction was completed, the solvent was removed under reduced pressure, and the product was washed with alcohol three times and dried to obtain modified tungsten diboride powder.

[0106] Comparative Example 1

[0107] An aluminum substrate material, the preparation method of which is different from that of Example 1 only in that the composition of the thermal conductive adhesive is slightly different, and the modified tungsten diboride powder in the thermal conductive adhesive composition of Example 1 is replaced with ordinary tungsten diboride powder. The composition of the thermal conductive adhesive of this comparative example, calculated by weight, includes:

[0108] 28 parts of terminal carboxyl nitrile rubber, 55 parts of epoxy resin, 9 parts of acrylic resin, 4.7 parts of polyvinyl butyral resin, 9.5 parts of tungsten diboride powder, 1 part of aluminum oxide powder, 0.9 parts of aluminum nitride powder, 1.8 parts of isophorone diamine and 32 parts of methyl ethyl ketone.

[0109] Comparative Example 2

[0110] An aluminum substrate material, the preparation method of which is different from that of Example 1 only in that the composition of the thermal conductive adhesive is slightly different, the modified tungsten diboride powder in the thermal conductive adhesive composition of Example 1 is replaced with mercaptolated tungsten diboride powder, the preparation of mercaptolated tungsten diboride powder is the same as that of Example 1, and the composition of the thermal conductive adhesive of this comparative example is calculated by weight, including:

[0111] 28 parts of carboxyl-terminated nitrile rubber, 55 parts of epoxy resin, 9 parts of acrylic resin, 4.7 parts of polyvinyl butyral resin, 9.5 parts of mercaptolated tungsten diboride powder, 1 part of alumina powder, 0.9 parts of aluminum nitride powder, 1.8 parts of isophorone diamine and 32 parts of methyl ethyl ketone.

[0112] Comparative Example 3

[0113] An aluminum substrate material, the preparation method of which is different from that of Example 1 only in that the composition of the thermal conductive adhesive is slightly different, the modified tungsten diboride powder in the thermal conductive adhesive composition of Example 1 is replaced by a mixture of tungsten diboride powder and modifier VBA-TZ, the preparation of the modifier VBA-TZ is the same as that of Example 1, and the composition of the thermal conductive adhesive of this comparative example is calculated by weight, including:

[0114] 28 parts of carboxyl-terminated nitrile rubber, 55 parts of epoxy resin, 9 parts of acrylic resin, 4.7 parts of polyvinyl butyral resin, 7.66 parts of tungsten diboride powder, 1.84 parts of modifier VBA-TZ, 1 part of alumina powder, 0.9 parts of aluminum nitride powder, 1.8 parts of isophorone diamine and 32 parts of methyl ethyl ketone.

[0115] In order to more clearly illustrate the content of the present invention, the performance of the thermal conductive adhesive of the aluminum substrate material prepared in Example 1 and Comparative Examples 1-3 was tested respectively, and the test standards were: peel strength refers to IPC TM-6502.4.9.1-1998, bending strength refers to GB / T 9341-2008, tensile strength refers to GB / T 1040-1992, and thermal conductivity refers to ASTM D5470. The test results are shown in Table 1:

[0116] Table 1 Performance test results of thermal conductive adhesives of different aluminum substrate materials

[0117] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Thickness(μm) 75 75 75 75 Peel strength (N / mm) 1.91 1.15 1.27 1.42 Bending strength(MPa) 158 121 129 137 Tensile strength(MPa) 90 78 82 85 Thermal conductivity (W / (m·K)) 2.73 2.81 2.80 2.32

[0118] It can be seen from the test results in Table 1 that the thermal conductive adhesive of the aluminum substrate material prepared in Example 1 of the present invention has better peel strength and tensile strength than the comparative example while maintaining a relatively high thermal conductivity, especially in terms of bending strength. This shows that as a thermal conductive adhesive for an aluminum substrate, it not only has good thermal conductivity, but also has excellent strength and flexibility. It can be bent and curved arbitrarily in combination with a flexible aluminum substrate and is not easy to break.

[0119] The above embodiments are only preferred embodiments of the present invention. The present invention cannot list all the embodiments one by one. Any technical solution adopting one of the above embodiments, or equivalent changes made according to the above embodiments, are within the protection scope of the present invention.

[0120] According to the disclosure and teaching of the above description, those skilled in the art to which the present invention belongs may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. In addition, although some specific terms are used in this specification, these terms are only for the convenience of description and do not constitute any limitation to the present invention. Other materials obtained by the same or similar methods and structures are all within the protection scope of the present invention.

Claims

1. A method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily, characterized in that: The following steps are involved: Step 1: Prepare suitable aluminum plates and copper foils in advance and keep the surfaces clean; Step 2, preparing a thermally conductive adhesive, wherein the components of the thermally conductive adhesive are calculated by weight and include: 22-35 parts of carboxyl-terminated nitrile rubber, 45-56 parts of epoxy resin, 8-12 parts of acrylic resin, 4-6.2 parts of polyvinyl butyral resin, 8.4-16.8 parts of thermally conductive modified filler, 1.5-2.6 parts of curing agent and 16-45 parts of solvent; Step 3, evenly coating the thermal conductive adhesive on the surface of the aluminum plate, and baking to form a thermal conductive adhesive layer; Step 4, pressing the rolled copper foil onto the thermal conductive adhesive layer, and then subjecting the laminate to an aging treatment, to obtain a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily; Wherein, the thermally conductive modified filler in step 2 includes modified tungsten diboride powder, aluminum oxide powder and aluminum nitride powder, and the mass ratio of the modified tungsten diboride powder, aluminum oxide powder and aluminum nitride powder is 5:0.1-1:0.1-1.

2. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 1, characterized in that: In the step 2, the curing agent is one or more combinations of ethylenediamine, isophoronediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

3. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 1, characterized in that: In step 2, the solvent is one or more of ethyl acetate, propyl acetate, butyl acetate, toluene, methyl ethyl ketone, N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide.

4. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 1, characterized in that: In step 2, the preparation method of modified tungsten diboride powder includes: S1. Weigh 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine and 4-vinylbenzaldehyde and add them to 1,4-dioxane. After fully stirring, introduce inert gas to replace the air, then dropwise add an acid catalyst, heat to 95-115°C, keep stirring for 12-36h, after the reaction is completed, remove the solvent under reduced pressure, wash and dry to obtain a modifier VBA-TZ; S2, mix the tungsten diboride powder WB2 and the ethanol solution, and after uniform dispersion, add γ-mercaptopropyltriethoxysilane, and reflux and stir for 6-12 hours at 60-80°C. After the treatment, filter and extract the residue, wash and dry to obtain the mercaptolated tungsten diboride powder HS-WB2; S3. Mix the modifier VBA-TZ and N,N-dimethylformamide DMF, stir and disperse them evenly, then add HS-WB2 powder, introduce inert gas to replace the air, stir and react under the conditions of photosensitizer and ultraviolet light irradiation, the reaction time is 1.2-2.4h, after the reaction is completed, remove the solvent under reduced pressure, wash and dry to obtain modified tungsten diboride powder.

5. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 4, characterized in that: In S1, the mass volume ratio of 4,4',4"-(1,3,5-triazine-2,4,6-triyl)triphenylamine, 4-vinylbenzaldehyde and 1,4-dioxane is (2.1-4.2) g:(0.3-0.6) g:(20-60) mL; the acidic catalyst is glacial acetic acid, and the added amount is 1%-5% of the mass of 4-vinylbenzaldehyde.

6. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 4, characterized in that: In S2, the mass volume ratio of tungsten diboride powder, γ-mercaptopropyltriethoxysilane and ethanol solution is 1 g: (0.23-0.46) g: (15-35) mL.

7. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 4, characterized in that: In S3, the mass volume ratio of mercaptolated tungsten diboride powder, modifier VBA-TZ and N,N-dimethylformamide is 1 g: (0.16-0.32) g: (20-40) mL; the ultraviolet light intensity is 280-560 mW / cm 2 The photosensitizer is benzoin dimethyl ether, and the added amount is 2.5%-7.5% of the mass of the modifier VBA-TZ.

8. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 1, characterized in that: In step 3, the thickness of the thermal conductive adhesive layer is 30-100 μm; the baking temperature is 50-110° C., and the baking speed is 10-50 m / min.

9. The method for preparing a flexible PCB aluminum substrate material that can be arbitrarily bent and shaped according to claim 4, characterized in that: In the step 4, the rolled copper foil is pressed onto the thermal conductive adhesive layer by a laminating machine, and the laminating working temperature of the laminating machine is set to 100-130°C; the aging process includes: performing an aging process in an oven with a working temperature set to 110-130°C for 15-50 minutes, and then controlling the oven temperature to rise to 180-200°C for aging for 15-50 minutes.

10. A flexible PCB aluminum substrate material that can be bent and shaped arbitrarily, characterized in that: The flexible PCB aluminum substrate material is prepared by the preparation method described in claim 1.