A method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily

Abstract

The present invention relates to the field of circuit boards, and more specifically, to a method for preparing a flexible aluminum PCB substrate material that can be arbitrarily bent and shaped. The flexible aluminum PCB substrate prepared by the present invention has an ingenious and rational structural design. The aluminum plate and copper foil are combined using a thermally conductive adhesive, resulting in excellent flexibility, resistance to breakage, and the ability to bend arbitrarily, meeting the diverse shapes and all-round lighting requirements of LED lamps. Furthermore, heat generated by the LED lamp is rapidly transferred to the aluminum substrate via the thermally conductive adhesive and then dissipated from the aluminum substrate, thereby achieving rapid heat dissipation and achieving excellent heat dissipation effects.

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 of long life, high luminous efficiency, low radiation and low power consumption.

[0003] While LED light sources offer high brightness output, they also generate significant heat. Consequently, operating in high-temperature environments can lead to color shift, reduced brightness, shortened lifespan, and even immediate failure. To prevent these issues, LED light sources must be able to promptly and adequately dissipate the heat generated during operation. Currently, printed circuit boards (PCBs) are commonly used to support LED light sources, meeting these thermal conductivity requirements.

[0004] Printed circuit boards (PCBs) support electronic components and provide electrical connections between them. Their manufacturing quality is crucial, directly impacting the cost and quality of electronic products and even the success of commercial competition. However, existing aluminum PCB substrates lack sufficient heat dissipation performance and are difficult to bend or flex. The thermally conductive adhesive is inflexible and easily breaks, making it difficult to achieve omnidirectional lighting with LED light sources and design various shapes. Furthermore, there are certain limitations on improving heat dissipation efficiency. Summary of the Invention

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

[0006] The purpose of the present invention is achieved by adopting 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: Prepare 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 it to form a thermal conductive adhesive layer;

[0012] In step 4, the rolled copper foil is pressed onto the thermal conductive adhesive layer, and then subjected 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 range of aluminum plates, among which O-state aluminum has better flexibility.

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

[0015] Preferably, in step 2, the thermally conductive modified filler includes modified tungsten diboride powder, alumina powder (spherical, diamond-shaped) 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 is a combination of one or more 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 16-20 wt%.

[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 preparation method of 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 thorough stirring, introduce inert gas to replace the air, then dropwise add the acidic catalyst, raise the temperature to 95-115°C, and stir at this temperature for 12-36 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, and wash the product with alcohol at least three times. After drying, obtain the modifier VBA-TZ.

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

[0024] S3. Mix the modifier VBA-TZ and N,N-dimethylformamide DMF, stir and disperse them evenly, 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 amount added 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 UV 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] Carboxyl-terminated nitrile rubber, epoxy resin and acrylic resin are weighed and mixed in a solvent, and after being completely dissolved, a mixed solution is obtained; a curing agent, a thermally conductive modified filler and polyvinyl butyral are added to the mixed solution, and then dispersed and stirred evenly to obtain a thermal 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 an operating 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 using 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 copper foil are combined by thermal conductive adhesive, so that it has good flexibility, is not easy to break, and can be bent arbitrarily, which can meet the diversified shapes and all-round lighting needs of LED lamps. 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 good heat dissipation effect.

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

[0041] 3. In addition, since rolled copper foil has excellent conductivity and high ductility, it further improves its overall flexibility, good flexibility, and long service life in meeting the needs of electrical conductivity. In addition, the overall structure is simple and easy to implement, which is conducive to widespread promotion and application. The method provided by the present invention has a simple process and can quickly produce arbitrarily bendable aluminum materials, greatly shortening the production cycle and improving production efficiency. 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 presence 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 define the scope of the present invention. Changes or adjustments in their relative relationships, without substantially changing the technical content, should also be regarded as the scope of the present invention.

[0043] In order to better understand the above technical solutions, 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 to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0044] The present invention will be further described below with reference to 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 via the thermally conductive adhesive. The components of the thermally conductive adhesive, calculated by weight, include:

[0047] 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 modified tungsten diboride powder, 1 part of aluminum oxide powder, 0.9 part of aluminum nitride powder, 1.8 parts of isophorone diamine and 32 parts of methyl ethyl ketone.

[0048] 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 epoxy resin model 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 degree of acetalization 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 into 40 mL of 1,4-dioxane, stir 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, and stir at this temperature for 24 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, and wash the product with alcohol at least three times. After drying, obtain the modifier VBA-TZ.

[0051] S2. 1 g of tungsten diboride powder (WB2, Φ = 5-10 μm) was mixed with 25 mL of 40 wt% ethanol solution. After uniform dispersion, 0.35 g of γ-mercaptopropyltriethoxysilane was added. The mixture was refluxed and stirred at 70° C. for 10 h. After the treatment, the residue was filtered and extracted, washed three times with alcohol, 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 and stirred to disperse 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 the light intensity of 420mW / cm 2The reaction was stirred under ultraviolet light irradiation for 1.8 hours. 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 aluminum substrate material that can be bent and shaped arbitrarily comprises the following steps:

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

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

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

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

[0058] (2.3) Mixing: Add isophorone diamine, modified tungsten diboride powder, aluminum oxide powder, aluminum nitride powder, and polyvinyl butyral to the mixed solution, and then disperse and stir uniformly for 1.5 hours at 30°C to prepare a thermal conductive adhesive;

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

[0060] (3.1) Coating: Using a coating machine, evenly coat the thermal conductive adhesive on one surface of the aluminum plate. 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) Use a laminating machine to laminate the rolled copper foil onto the thermal conductive adhesive layer. The laminating operating temperature of the laminating machine is set to 115 degrees.

[0064] (4.2) Push the product 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 arbitrarily bent and shaped 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 copper foil of O-state aluminum;

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

[0070] (2.1) Prepare the raw materials: The raw materials by weight are: 22 parts carboxyl-terminated nitrile rubber, 45 parts epoxy resin E-42, 8 parts acrylic resin, 1.8 parts diethylenetriamine, 7 parts modified tungsten diboride powder, 0.7 parts alumina powder, 0.7 parts aluminum nitride powder, 4 parts polyvinyl butyral, and 16 parts ethyl acetate;

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

[0072] (2.3) Mixing: Add diethylenetriamine, modified tungsten diboride powder, aluminum oxide powder, aluminum nitride powder, and polyvinyl butyral to the mixed solution, and then disperse and stir them uniformly for 1 hour at 20°C to prepare a thermal conductive adhesive;

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

[0074] (3.1) Coating: Using a coating machine, evenly coat the thermal conductive adhesive on one surface of the aluminum plate. 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) Use a laminating machine to laminate the rolled copper foil onto the thermal conductive adhesive layer. The laminating operating temperature of the laminating machine is set to 100 degrees.

[0078] (4.2) Push the product 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 arbitrarily bent and shaped 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 copper foil of O-state aluminum;

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

[0084] (2.1) Prepare the raw materials: The raw materials are as follows by weight: 35 parts of carboxyl-terminated nitrile rubber, 6 parts of epoxy resin E-515, 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) Dissolution: Completely dissolve the carboxyl-terminated nitrile rubber, epoxy resin E-51, and acrylic resin in toluene to obtain a mixed solution;

[0086] (2.3) Mixing: Add ethylenediamine, modified tungsten diboride powder, aluminum oxide powder, aluminum nitride powder, and polyvinyl butyral to the mixed solution, and then disperse and stir them uniformly for 2 hours at 40°C to prepare a thermal conductive adhesive;

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

[0088] (3.1) Coating: Use a coating machine to evenly coat the thermal conductive adhesive on one surface of the aluminum plate. 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) Use a laminating machine to laminate the rolled copper foil onto the thermal conductive adhesive layer. The laminating operating temperature of the laminating machine is set to 130 degrees.

[0092] (4.2) Push the product 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 includes:

[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 into 20 mL of 1,4-dioxane, stir thoroughly, introduce inert gas to replace the air, then dropwise add glacial acetic acid in an amount of 1% by mass of 4-vinylbenzaldehyde, heat to 95°C, and stir at this temperature for 12 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, and wash the product with alcohol at least three times. After drying, obtain the modifier VBA-TZ.

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

[0099] S3, 0.16g modifier VBA-TZ and 20mL DMF were mixed and stirred to disperse 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 the modifier VBA-TZ. Under the light intensity of 280mW / cm 2 The reaction was stirred under ultraviolet light irradiation for 1.2 hours. 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 includes:

[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 into 60 mL of 1,4-dioxane, stir thoroughly, introduce inert gas to replace the air, then dropwise add glacial acetic acid in an amount of 5% by mass of 4-vinylbenzaldehyde, heat to 115° C., and stir at this temperature for 36 hours. After the reaction is complete, cool to room temperature, remove the solvent under reduced pressure, and wash the product with alcohol at least three times. After drying, obtain the modifier VBA-TZ.

[0104] S2. 1 g of tungsten diboride powder (WB2, Φ = 5-10 μm) was mixed with 35 mL of 60 wt% ethanol solution. After uniform dispersion, 0.46 g of γ-mercaptopropyltriethoxysilane was added and the mixture was refluxed and stirred at 80° C. for 12 h. After the treatment, the residue was filtered and extracted, washed three times with alcohol, 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 and stirred to disperse 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 the light intensity of 560mW / cm 2 The reaction was stirred under ultraviolet light irradiation for 2.4 hours. 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 differs 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 of Example 1 is replaced with ordinary tungsten diboride powder. The composition of the thermal conductive adhesive of this comparative example, calculated by parts by weight, includes:

[0108] 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 tungsten diboride powder, 1 part of aluminum oxide powder, 0.9 part 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 differs 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. The components of the thermal conductive adhesive of this comparative example, calculated by parts by weight, include:

[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 aluminum oxide powder, 0.9 part 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 differs 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 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. The components of the thermal conductive adhesive of this comparative example, calculated by parts by weight, include:

[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] To more clearly illustrate the present invention, the properties of the thermally conductive adhesives prepared for aluminum substrates in Example 1 and Comparative Examples 1-3 were tested, respectively. The test standards were: peel strength according to IPC TM-6502.4.9.1-1998, flexural strength according to GB / T 9341-2008, tensile strength according to GB / T 1040-1992, and thermal conductivity according to ASTM D5470. The test results are shown in Table 1.

[0116] Table 1 Performance test results of thermal conductive adhesives for 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 Flexural 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 excellent strength and flexibility. It can be bent and curved arbitrarily when combined with a flexible aluminum substrate and is not easy to break.

[0119] The above embodiments are only preferred implementations of the present invention. The present invention cannot list all implementations one by one. Any technical solution that adopts one of the above embodiments, or equivalent changes made based on the above embodiments, are within the scope of protection of the present invention.

[0120] Based on the disclosure and teachings 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 scope of protection of the claims of the present invention. In addition, although some specific terms are used in this description, these terms are only for convenience of description and do not constitute any limitation to the present invention. Other materials obtained using the same or similar methods and structures are all within the scope of protection 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 rolled copper foil in advance and keep the surfaces clean; Step 2: Prepare thermal conductive adhesive. The components of the thermal 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 it to form a thermal conductive adhesive layer; Step 4: Laminating the rolled copper foil on 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; Wherein, the thermally conductive modified filler in step 2 comprises 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; In step 2, the preparation method of the 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 thorough stirring, introduce inert gas to replace the air, then dropwise add the acidic catalyst, raise the temperature to 95-115°C, and stir at this temperature for 12-36 hours. After the reaction is completed, remove the solvent under reduced pressure, wash, and dry to obtain the modifier VBA-TZ. S2. Mix tungsten diboride powder WB2 and ethanol solution, disperse them evenly, add γ-mercaptopropyltriethoxysilane, and reflux with stirring at 60-80°C for 6-12 hours. After the treatment, filter and extract the residue, wash and dry it to obtain mercaptolated tungsten diboride powder HS-WB2; S3. Mix the modifier VBA-TZ and N,N-dimethylformamide DMF, stir and disperse them evenly, 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.

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

3. The method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily 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 bent and shaped arbitrarily according to claim 1, 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.

5. The method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily according to claim 1, characterized in that: In the 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.

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

7. The method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily 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.

8. The method for preparing a flexible PCB aluminum substrate material that can be bent and shaped arbitrarily according to claim 1, characterized in that: In 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 set at a working temperature of 110-130°C for 15-50 minutes, and then controlling the oven temperature to 180-200°C for aging for 15-50 minutes.

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