Insulation composite material containing carbon fiber skeleton and preparation method and application thereof

Abstract

The present invention relates to the technical field of insulating composite materials, and specifically to an insulating composite material containing a carbon fiber skeleton, a preparation method and an application thereof, wherein the composite material comprises a carbon fiber skeleton layer, and a water-resistant adhesive layer, an anti-permeation film layer, an oil-resistant adhesive layer and an insulating paper layer are sequentially arranged on both sides of the carbon fiber skeleton layer outward; in terms of weight parts, the carbon fiber skeleton layer comprises 1 part of carbon fiber chopped fibers, 1.5-2 parts of fillers, and 3-3.5 parts of adhesives. The insulating composite material of the present invention has both water resistance and oil resistance, and has extremely strong electrical insulation, thermal conductivity, flame retardancy and mechanical strength. The insulating composite material is particularly suitable for the interface composite material between electronic components and radiators, and has the functions of filling interface gaps, reducing interface thermal resistance, improving chip heat dissipation capacity, and maintaining a relatively high resistivity, so as to achieve efficient heat dissipation of the chip while reducing the risk of leakage.

Description

Technical Field

[0001] The invention relates to an insulating composite material containing a carbon fiber skeleton, a preparation method and an application thereof, and belongs to the technical field of insulating composite materials. Background Art

[0002] At present, as the key basic materials of the equipment industry, insulating materials are widely used in many fields such as electricity, motors, electronic information, rail transportation, aerospace, and military industry. The main function of insulating materials is to isolate charged conductors of different potentials in electrical equipment so that the current can flow along a certain path. It can also play the role of mechanical support and fixation, as well as arc extinguishing, heat dissipation, energy storage, moisture-proof, mildew-proof or improve the potential distribution of the electric field and protect the conductor. Therefore, the insulating material is required to have the highest possible insulation resistance, heat resistance, and moisture resistance, and also requires a certain mechanical strength. Aramid paper and some insulating films such as polyimide film and polyethylene film, when used alone, cannot meet the current equipment industry requirements for heat resistance, oil resistance, water resistance and mechanical strength of insulating materials. The preparation of aramid paper and insulating film into composite materials can better meet the needs of downstream applications. As an important component of aramid paper insulating materials, the performance of adhesives also largely determines the performance and application of composite insulating materials.

[0003] As one of the five major polymer materials, adhesives have become an indispensable new material in the development of high-tech with the development of national economy and science and technology. They have been widely used in various sectors of the national economy and related fields of daily life. Especially in recent years, through continuous technological innovation and material optimization, adhesives have gradually become one of the core elements to improve the stability and reliability of power systems. According to the demand for insulation materials for motors, insulation materials are required to have good mechanical strength, electrical properties, thermal stability and chemical compatibility. Adhesives for insulation materials with better high temperature, oil resistance, and moisture and heat aging resistance can improve the performance and quality of insulation materials and promote the upgrading of insulation materials such as aramid paper composite materials. However, there are few high-end adhesive products in China.

[0004] Usually, elastic materials with high thermal conductivity in the vertical direction are introduced into the interface between electronic components and heat sinks to fill the interface gaps, reduce the interface thermal resistance, and improve the heat dissipation capacity of the chip. Such materials are called thermal interface materials. In modern electronic devices, chip-level thermal management requires that the thermal interface material have both high out-of-plane thermal conductivity and high resistivity to achieve efficient heat dissipation of the chip while reducing the risk of leakage.

[0005] Chinese patent application CN116968405A discloses an insulating composite material, which includes a film layer, an insulating paper layer and an adhesive layer, wherein the adhesive layer is located between the film layer and the insulating paper layer, and the insulating composite material has both high stiffness and high temperature resistance. Chinese patent CN109109407B discloses an insulating material prepared by a vacuum induction method, including an insulating unit, each insulating unit including a first drainage fabric layer, a first fiber fabric layer, an insulating film, a second fiber fabric layer and a second drainage fabric layer stacked in sequence, and an insulating material with epoxy resin as a reinforcing matrix, which improves the insulation resistance of the insulating composite material. However, the above-mentioned material has poor thermal conductivity and cannot simultaneously meet the oil resistance and water resistance of the insulating material.

[0006] Based on the above-mentioned prior art, there are technical problems in the prior art that need to be solved urgently, such as the inability of insulating composite materials to take into account both water resistance and oil resistance, poor electrical insulation performance, and low mechanical strength. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides an insulating composite material containing a carbon fiber skeleton, a preparation method and an application thereof. The prepared composite material has a lower curing temperature and can also have good high temperature resistance, water resistance and oil resistance. Its thermal conductivity, flame retardancy and mechanical strength meet the application requirements of electrical components for insulating materials.

[0008] The technical solution of the present invention to solve the above technical problems is as follows: an insulating composite material containing a carbon fiber skeleton, the composite material comprising a carbon fiber skeleton layer, and a water-resistant adhesive layer, an anti-permeation film layer, an oil-resistant adhesive layer and an insulating paper layer are sequentially arranged on both sides of the carbon fiber skeleton layer outward;

[0009] In terms of weight, the carbon fiber skeleton layer includes 1 part of carbon fiber chopped fibers, 1.5-2 parts of fillers, and 3-3.5 parts of adhesives;

[0010] The water-resistant adhesive layer is prepared by coating a water-resistant adhesive composed of an acrylate-modified phenolic epoxy resin adhesive and a curing agent, wherein the acrylate-modified phenolic epoxy resin adhesive comprises 20-30 parts of bisphenol A epoxy resin, 15-25 parts of phenolic resin, 30-40 parts of an organic solvent, 10-15 parts of benzyl methacrylate monomers, 0.3-3 parts of an initiator, 10-15 parts of a polysiloxane compound, and 5-10 parts of silicon dioxide;

[0011] The oil-resistant adhesive layer is prepared by coating an oil-resistant adhesive composed of an acrylate-modified epoxy resin adhesive, a modified acid anhydride curing agent, a polysiloxane compound, a metal oxide, and an organic solvent; the modified acid anhydride curing agent includes a phthalic anhydride compound and an imidazole accelerator, and in the modified acid anhydride curing agent, the mass ratio of the phthalic anhydride compound to the imidazole accelerator is (89-97%):(3-11%).

[0012] Furthermore, the anti-permeation film layer is selected from any one of a polyimide film, a polyethylene naphthalate film, a polyphenylene sulfide film, and a polyetheretherketone film;

[0013] The insulating paper layer is selected from meta-aramid staple fiber paper with a thickness of 0.04 mm, 0.05 mm, 0.1 mm, 0.250 mm or 0.300 mm.

[0014] Furthermore, in the carbon fiber skeleton layer, the filler is aluminum oxide nanoparticles or calcium oxide nanoparticles; the adhesive is an organic silicone resin AB component, the A component of the organic silicone resin AB component includes methyl methacrylate, formaldehyde and pyridine, and the B component of the organic silicone resin AB component includes aniline, modified polyamine, amino polyammonium acid and methylphenyl polysiloxane; the carbon fiber chopped fibers have a length of 1-3 mm and a diameter of 20-100 μm;

[0015] The preparation method of the carbon fiber skeleton layer is: after the carbon fiber chopped fibers and the filler are evenly dispersed in the adhesive, the carbon fiber skeleton layer is formed by coating and heat curing, the coating thickness is 0.1-0.2mm, the heating curing temperature is 115-125°C, and the heating curing time is 3-5h.

[0016] Furthermore, the preparation method of the acrylate modified phenolic epoxy resin adhesive is:

[0017] The bisphenol A epoxy resin, the phenolic resin and the organic solvent are uniformly mixed to obtain a first mixture; the benzyl methacrylate monomer, the initiator and the polysiloxane compound are uniformly mixed to obtain a second mixture; the second mixture is added dropwise to the first mixture at 110-130° C., the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and then silicon dioxide is added, the reaction is continued for 0.5-1 hour, and after the reaction is completed, the temperature is cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive;

[0018] The benzyl methacrylate monomer is any one of butyl acrylate, ethyl acrylate and methyl acrylate;

[0019] The organic solvent is ethyl acetate, butyl acetate or xylene;

[0020] The initiator is azobisisobutyronitrile, dibenzoyl peroxide or benzoyl peroxide.

[0021] Furthermore, the curing agent used in the water-resistant adhesive layer is polyamide 650;

[0022] When the water-resistant adhesive is used, the acrylate-modified phenolic epoxy resin adhesive and the curing agent are mixed evenly in a weight ratio of (5-10):1 and then coated.

[0023] Furthermore, the preparation method of the acrylate modified epoxy resin adhesive is as follows: according to the weight parts, 30-60 parts of epoxy resin and 30-60 parts of solvent are mixed evenly to obtain a first mixture; 3-7 parts of acrylate monomer, 1-5 parts of acrylic acid, 10-30 parts of styrene, and 0.1-1 parts of initiator are mixed evenly to obtain a second mixture; under the condition of 110-140° C., the second mixture is added dropwise to the first mixture, and the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and the temperature is lowered to room temperature to obtain the acrylate modified epoxy resin adhesive;

[0024] The solvent is ethyl acetate, butyl acetate or xylene;

[0025] The initiator is benzoyl peroxide or tert-butyl hydroperoxide. Furthermore, when the oil-resistant adhesive is used, the acrylate-modified epoxy resin, modified acid anhydride curing agent, vinyl silicone oil, metal oxide, and organic solvent are mixed evenly in a weight ratio of (5-10): 1: (0.2-0.5): (1-2): (1-4) and then coated;

[0026] The metal oxide is any one of aluminum oxide, calcium oxide, sodium oxide, and iron oxide;

[0027] The organic solvent is ethyl acetate, butyl acetate or xylene.

[0028] The present invention also discloses a method for preparing an insulating composite material containing a carbon fiber skeleton, the preparation method comprising:

[0029] S1. Apply oil-resistant adhesive on one side of the insulating paper layer, bake it in the tunnel, and then hot-press and bond it with the anti-permeation film layer;

[0030] S2, coating a water-resistant adhesive on the other side of the anti-permeation film layer in step S1, and after baking in the tunnel, evenly coating a mixture of carbon fiber staple fibers, adhesive and filler on the water-resistant adhesive layer, and then heating and curing at 115-125° C. for 3-5 hours to form a carbon fiber skeleton layer;

[0031] S3, evenly coating the surface of the carbon fiber skeleton layer with a water-resistant adhesive, baking it in a tunnel, and then hot-pressing and laminating it with the anti-permeation film layer;

[0032] S4, coating the other side of the anti-permeation film layer in step S3 with an oil-resistant adhesive, baking it in a tunnel, and then hot-pressing and laminating it with the insulating paper layer;

[0033] S5, performing a aging treatment to obtain the insulating composite material.

[0034] Furthermore, in steps S1-S4, the tunnel baking conditions are: baking temperature 60-80°C, baking time 20-40min;

[0035] In steps S1-S4, the hot pressing bonding conditions are: hot pressing bonding temperature 80-110°C, composite pressure 0.5-1.2MPa, and bonding time 10-15s;

[0036] In step S5, the aging treatment conditions are: aging temperature is 75-85°C, and aging time is 10-12h.

[0037] The invention also discloses an application of an insulating composite material containing a carbon fiber skeleton, wherein the insulating composite material is applied as an interface insulating heat-conducting and filling material between electronic components and a heat sink.

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

[0039] The insulating composite material of the present invention uses carbon fiber as a skeleton support material, which improves the mechanical strength and thermal conductivity of the insulating composite material. The tensile strength of the insulating composite material is not less than 164 N / cm, and can even reach 190 N / cm. The out-of-plane thermal conductivity can reach not less than 14.1 W / (m K), and can reach 18.7 W / (m K). The volume resistivity is not less than 5.4*10 9 Ω·cm, even up to 8.6*10 9 The insulating composite material has a high temperature resistance of 220-300°C.

[0040] The insulating composite material of the present invention uses an oil-resistant adhesive and a water-resistant adhesive at different levels, so that the insulating composite material has both water resistance and oil resistance.

[0041] The insulating composite material described in the present invention has an additional reverse osmosis film layer, which can effectively prevent the adhesive from penetrating through the insulating composite material during the preparation process, and can also prevent water and oil from penetrating through the insulating composite material during use, causing electrical operation failures. At the same time, the anti-permeability film itself has good insulation properties, and the prepared insulating composite material can be applied to the field of insulating materials.

[0042] The insulating composite material of the present invention is both water-resistant and oil-resistant, and has extremely strong electrical insulation, thermal conductivity, flame retardancy and mechanical strength. It makes up for the shortcomings of the existing insulating materials, which have insufficient thermal conductivity and mechanical strength. The insulating composite material is particularly suitable for the interface composite material between electronic components and radiators, and has the functions of filling interface gaps, reducing interface thermal resistance, improving chip heat dissipation capacity, and maintaining a relatively high resistivity, so as to achieve efficient heat dissipation of the chip while reducing the risk of leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a structural model diagram of the insulating composite material of the present invention;

[0044] Figure 2 is a scanning electron microscope image of the carbon fiber chopped fibers in Example 1;

[0045] Figure 3 This is a scanning electron microscope image of the carbon fiber skeleton layer in Example 1;

[0046] In the figure, 1. Carbon fiber skeleton layer; 2. Water-resistant adhesive layer; 3. Anti-penetration film layer; 4. Oil-resistant adhesive layer; 5. Insulation paper layer. DETAILED DESCRIPTION

[0047] The specific implementation of the present invention is described in detail below. The present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used are only for describing specific embodiments and are not intended to limit the present invention.

[0049] like Figure 1 As shown, an insulating composite material containing a carbon fiber skeleton, the composite material comprises a carbon fiber skeleton layer 1, and the two sides of the carbon fiber skeleton layer 1 are sequentially provided with a water-resistant adhesive layer 2, an anti-permeation film layer 3, an oil-resistant adhesive layer 4 and an insulating paper layer 5 outwardly;

[0050] In terms of weight, the carbon fiber skeleton layer 1 includes 1 part of carbon fiber chopped fibers, 1.5-2 parts of fillers, and 3-3.5 parts of adhesives;

[0051] The water-resistant adhesive layer 2 is made by coating a water-resistant adhesive composed of an acrylate-modified phenolic epoxy resin adhesive and a curing agent, wherein the acrylate-modified phenolic epoxy resin adhesive comprises 20-30 parts of bisphenol A epoxy resin, 15-25 parts of phenolic resin, 30-40 parts of an organic solvent, 10-15 parts of benzyl methacrylate monomers, 0.3-3 parts of an initiator, 10-15 parts of a polysiloxane compound, and 5-10 parts of silicon dioxide;

[0052] The oil-resistant adhesive layer 4 is prepared by coating an oil-resistant adhesive composed of an acrylate-modified epoxy resin adhesive, a modified acid anhydride curing agent, a polysiloxane compound, a metal oxide, and an organic solvent; the modified acid anhydride curing agent includes a phthalic anhydride compound and an imidazole accelerator, and in the modified acid anhydride curing agent, the mass ratio of the phthalic anhydride compound and the imidazole accelerator is (89-97%):(3-11%).

[0053] Specifically, the anti-permeation film layer 3 is selected from any one of polyimide film (Upilex), polyethylene naphthalate film (PEN), polyphenylene sulfide film (PPS), polyetheretherketone film (solvent-resistant PEEK film) (the film thickness is maintained at 50-75 μm);

[0054] The insulating paper layer 5 is selected from meta-aramid staple fiber paper with a thickness of 0.04 mm, 0.05 mm, 0.1 mm, 0.250 mm or 0.300 mm. In the embodiment of the present invention, the meta-aramid staple fiber paper manufactured by Minshida Company is selected, which has excellent fire retardant properties.

[0055] Specifically, in the carbon fiber skeleton layer 1, the filler is aluminum oxide nanoparticles or calcium oxide nanoparticles; the adhesive is silicone resin AB component; the carbon fiber chopped fibers have a length of 1-3 mm and a diameter of 20-100 μm;

[0056] The preparation method of the carbon fiber skeleton layer 1 is: after the carbon fiber chopped fibers and the filler are evenly dispersed in the adhesive, the carbon fiber skeleton layer 1 is formed by coating and heat curing, the coating thickness is 0.1-0.2mm, the heating curing temperature is 115-125°C, and the heating curing time is 3-5h.

[0057] Specifically, the preparation method of the acrylate modified phenolic epoxy resin adhesive is:

[0058] The bisphenol A epoxy resin, the phenolic resin and the organic solvent are uniformly mixed to obtain a first mixture; the benzyl methacrylate monomer, the initiator and the polysiloxane compound are uniformly mixed to obtain a second mixture; the second mixture is added dropwise to the first mixture at 110-130° C., the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and then silicon dioxide (particle size 1-100 nm) is added, the reaction is continued for 0.5-1 hour, and after the reaction is completed, the temperature is cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive;

[0059] The benzyl methacrylate monomer is any one of butyl acrylate, ethyl acrylate and methyl acrylate.

[0060] Specifically, the curing agent used in the water-resistant adhesive is polyamide 650;

[0061] When the water-resistant adhesive is used, the acrylate-modified phenolic epoxy resin adhesive and the curing agent are mixed at a weight ratio of (5-10):1 at room temperature for 0.5-1h to be evenly mixed before coating.

[0062] Specifically, the preparation method of the acrylate-modified epoxy resin adhesive is as follows: according to the weight parts, 30-60 parts of epoxy resin and 30-60 parts of solvent are mixed evenly to obtain a first mixture; 3-7 parts of acrylate monomer, 1-5 parts of acrylic acid, 10-30 parts of styrene, and 0.1-1 parts of initiator are mixed evenly to obtain a second mixture; under the condition of 110-140° C., the second mixture is added dropwise to the first mixture, and the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and the temperature is cooled to room temperature to obtain the acrylate-modified epoxy resin adhesive.

[0063] Specifically, the preparation process of the modified anhydride curing agent is as follows: a phthalic anhydride compound and an imidazole accelerator are added into a reaction bottle according to the mass percentage (89-97%): (3-11%), a stirring rate is set to 1600-2600 r / min, and high-speed stirring is performed at room temperature for 0.5-1h to obtain a modified anhydride curing agent.

[0064] Specifically, when the oil-resistant adhesive is used, the acrylate-modified epoxy resin, the modified acid anhydride curing agent, the polysiloxane compound, the metal oxide, and the organic solvent are mixed evenly in a weight ratio of (5-10): 1: (0.2-0.5): (1-2): (1-4) and then applied;

[0065] The metal oxide is any one of aluminum oxide, calcium oxide, sodium oxide, and iron oxide (particle size 10-100 μm). Adding metal oxide can significantly improve its thermal conductivity.

[0066] A method for preparing an insulating composite material containing a carbon fiber skeleton, the preparation method comprising:

[0067] S1, applying an oil-resistant adhesive to one side of the insulating paper layer 5, baking it in a tunnel, and then hot-pressing it with the anti-permeation film layer 3;

[0068] S2, coating a water-resistant adhesive on the other side of the anti-permeation film layer 3 of step S1, and after baking in the tunnel, evenly coating a mixture of carbon fiber staple fibers, adhesive and filler on the water-resistant adhesive layer, and then heating and curing at 115-125° C. for 3-5 hours to form a carbon fiber skeleton layer 1;

[0069] S3, evenly coating the surface of the carbon fiber skeleton layer 1 with a water-resistant adhesive, baking it in a tunnel, and then hot-pressing it with the anti-permeation film layer 3;

[0070] S4, coating the other side of the anti-permeation film layer 3 in step S3 with an oil-resistant adhesive, baking it in a tunnel, and then hot-pressing and laminating it with the insulating paper layer 5;

[0071] S5. Performing a curing treatment so that each adhesive is cured into a corresponding adhesive layer to obtain the insulating composite material.

[0072] Specifically, the insulating composite material comprises, from bottom to top, an insulating paper layer 5, an oil-resistant adhesive layer 4, an anti-permeation film layer 3, a water-resistant adhesive layer 2, a carbon fiber skeleton layer 1, a water-resistant adhesive layer 2, an anti-permeation film layer 3, an oil-resistant adhesive layer 4, and an insulating paper layer 5. The thickness of the insulating composite material is 0.4-0.8 mm.

[0073] Specifically, in steps S1-S4, the tunnel baking conditions are: baking temperature 60-80°C, baking time 20-40min;

[0074] In steps S1-S4, the hot pressing bonding conditions are: hot pressing bonding temperature 80-110°C, composite pressure 0.5-1.2MPa, and bonding time 10-15s;

[0075] In step S5, the aging treatment conditions are: aging temperature is 75-85°C, and aging time is 10-12h.

[0076] An application of an insulating composite material containing a carbon fiber skeleton, wherein the insulating composite material is used as an interface insulating, heat-conducting and filling material between electronic components and a heat sink.

[0077] The types and model information of chemical substances involved in the embodiments of the present invention are as follows:

[0078] 1. Raw material information involved in preparing carbon fiber skeleton layer 1:

[0079] Silicone resin AB components: Component A: 150 parts of methyl methacrylate, 95 parts of formaldehyde (aqueous solution of formaldehyde) with a mass concentration of 38% and 0.25 parts of pyridine; Component B: 60 parts of aniline, 30 parts of denatured polyamine (LSC-51, number average molecular weight 3000-5000), 25 parts of amino polyammonium acid (γ-PGA, number average molecular weight 500-5000) and 5 parts of methylphenyl polysiloxane (Bh012, viscosity 125×10 -6 Pa·s). The amount of each raw material used may fluctuate, which is not a limitation of the present invention.

[0080] 2. The raw material information involved in preparing the water-resistant adhesive layer 2 is:

[0081] Bisphenol A epoxy resin: E44 or E51;

[0082] Phenolic resin: methyl phenolic resin (molecular weight 800-1000);

[0083] Organic solvent: ethyl acetate, butyl acetate or xylene;

[0084] Initiator: azobisisobutyronitrile, dibenzoyl peroxide or benzoyl peroxide;

[0085] Polysiloxane compound: methylphenyl polysiloxane (SH-3047 purchased from Hubei Longsheng Sihai New Materials Co., Ltd.).

[0086] 3. The raw material information involved in preparing the oil-resistant adhesive layer 4 is:

[0087] Epoxy resin: E44 or E51;

[0088] Solvent: ethyl acetate, butyl acetate or xylene;

[0089] Initiator: benzoyl peroxide or tert-butyl hydroperoxide;

[0090] Phthalic anhydride compounds: methyltetrahydrophthalic anhydride;

[0091] Imidazole accelerator: 2-methylimidazole, 2-ethylimidazole or 2-phenylimidazole;

[0092] Polysiloxane compound: methylphenyl polysiloxane (SH-3047 purchased from Hubei Longsheng Sihai New Materials Co., Ltd.);

[0093] Organic solvent: ethyl acetate or butyl acetate.

[0094] Example 1

[0095] 1. Preparation of oil-resistant adhesive:

[0096] (1) According to the weight ratio, 30 parts of epoxy resin (E44) and 30 parts of xylene are added to a reaction bottle according to a set ratio, the temperature is set to 120°C, and the temperature is raised while stirring to obtain a first mixture. In addition, 5 parts of butyl acrylate, 3 parts of acrylic acid, 15 parts of styrene, and 0.2 parts of benzoyl peroxide are mixed according to a certain ratio to obtain a second mixture. When the reaction temperature rises to the target temperature, the second mixture is added dropwise to the first mixture system, and stirring is maintained at the target temperature while adding dropwise. The addition is controlled to be complete within 3 hours, and the reaction is continued for 2 hours. The temperature is lowered to room temperature to obtain an acrylate-modified epoxy resin adhesive;

[0097] (2) Methyltetrahydrophthalic anhydride and 2-methylimidazole were weighed in a mass percentage of 89:11, placed in a reaction bottle, and stirred at room temperature for 30 minutes using a high-speed disperser at a stirring speed of 2000 r / min to obtain a modified anhydride curing agent.

[0098] (3) The acrylate-modified epoxy resin adhesive, the modified acid anhydride curing agent, the methylphenyl polysiloxane, the aluminum oxide, and the ethyl acetate were mixed at a weight ratio of 7:1:0.2:1:4 at room temperature for 0.5 h to obtain an oil-resistant adhesive for later use.

[0099] 2. Preparation of water-resistant adhesive:

[0100] (1) According to the weight percentage, 20 parts of bisphenol A epoxy resin (E44), 17 parts of phenolic resin and 30 parts of butyl acetate were added to the reaction bottle according to the set ratio, the temperature was set to 125°C, and the temperature was raised while stirring to obtain a first mixture. In addition, 10 parts of benzyl methacrylate, 0.3 parts of azobisisobutyronitrile and 10 parts of methylphenyl polysiloxane were mixed according to the ratio to obtain a second mixture. When the temperature in the system was raised to the target temperature, the second mixture was added dropwise to the first mixture system in the reaction bottle, and the stirring was maintained at the target temperature while adding dropwise. The addition was controlled to be complete within 3 hours, and the reaction was carried out at the target temperature for 2 hours. Then, 5 parts of silica were added, and the reaction was continued for 1 hour. After the reaction was completed, the temperature was cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive.

[0101] (2) Low molecular weight polyamide 650 is used as curing agent.

[0102] (3) The acrylate-modified phenolic epoxy resin adhesive and the polyamide 650 curing agent were mixed at a weight ratio of 8:1 at room temperature for 0.5 h to obtain a water-resistant adhesive for later use.

[0103] 3. The preparation method of the carbon fiber skeleton layer is:

[0104] According to the weight percentage, 1 part of carbon fiber chopped fiber and 2 parts of aluminum oxide nanoparticles are evenly dispersed in 3 parts of silicone resin AB component, stirred and mixed evenly, and evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.1mm. Then, it is heated at 120℃ for 5 hours to cure it and form a carbon fiber skeleton layer.

[0105] 4. Preparation process of insulating composite materials:

[0106] The oil-resistant adhesive is applied to one side of the insulating paper layer (thickness of 0.1 mm), and after being slightly dried in the tunnel, it is hot-pressed with the polyimide film, and then the water-resistant adhesive is applied to the other side of the polyimide film layer. After being slightly dried in the tunnel, the carbon fiber layer is carbon fiber short fiber, adhesive, and filler. After stirring and mixing, it is evenly applied on the surface of the water-resistant adhesive layer with a thickness of 0.1 mm. Then heat it at 120 ° C for 5 hours to solidify it to form a carbon fiber skeleton layer. The surface of the carbon fiber skeleton layer is evenly coated on the water-resistant adhesive layer, and after being slightly dried in the tunnel, it is hot-pressed with the polyimide film. The oil-resistant adhesive is applied to the other side of the polyimide film. After being slightly dried in the tunnel, it is hot-pressed with the insulating paper layer, and finally enters the 80 ° C curing room for 12 hours to solidify the adhesive into an adhesive layer. The composite material after bonding is an insulating composite material with a structure of insulating paper layer-oil-resistant adhesive layer-polyimide film layer-water-resistant adhesive layer-carbon fiber skeleton layer-water-resistant adhesive layer-polyimide film layer-oil-resistant adhesive layer-insulating paper layer from bottom to top.

[0107] The conditions for the drying operation in the tunnel are as follows: the baking temperature is 70°C and the baking time is 30 minutes;

[0108] The hot pressing bonding conditions are as follows: hot pressing bonding temperature of 100° C., composite pressure of 1.0 MPa, and bonding time of 15 s.

[0109] Example 2

[0110] 1. Preparation of oil-resistant adhesive:

[0111] (1) According to the weight ratio, 40 parts of epoxy resin (E51) and 40 parts of butyl acetate were added to a reaction bottle according to the set ratio, and the temperature was set to 120°C. The temperature was raised while stirring to obtain a first mixture. 7 parts of butyl acrylate, 3 parts of acrylic acid, 20 parts of styrene, and 0.5 parts of tert-butyl hydroperoxide were mixed according to the ratio. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system. The stirring was maintained at the target temperature while adding dropwise. The addition was controlled to be complete within 3 hours. The reaction was continued for 3 hours, and the temperature was lowered to room temperature to obtain an acrylate-modified epoxy resin adhesive.

[0112] (2) Methyltetrahydrophthalic anhydride and 2-methylimidazole were weighed in a mass percentage of 93:7, placed in a reaction bottle, and stirred at room temperature for 30 minutes using a high-speed disperser at a stirring speed of 2000 r / min to obtain a modified anhydride curing agent.

[0113] (3) The acrylate modified epoxy resin adhesive, modified anhydride curing agent, methyl vinyl polysiloxane, calcium oxide, and ethyl acetate were mixed at a weight ratio of 9:1:0.3:1.5:4 at room temperature for 0.5 h to obtain an oil-resistant adhesive for later use.

[0114] 2. Preparation of water-resistant adhesive:

[0115] (1) According to the weight percentage, 23 parts of bisphenol A epoxy resin (E51), 20 parts of phenolic resin and 35 parts of xylene are added to the reaction bottle according to the set ratio, the temperature is set to 130°C, and the first mixture is obtained while stirring. In addition, 14 parts of benzyl methacrylate, 1 part of dibenzoyl peroxide and 13 parts of methylphenyl polysiloxane are mixed according to the ratio. When the reaction temperature rises to the target temperature, the second mixture is added dropwise to the first mixture system in the reaction bottle, and the stirring is maintained at the target temperature while adding dropwise. The addition is controlled to be complete within 3 hours, and the reaction is carried out at the target temperature for 2 hours, and then 7 parts of silicon dioxide are added. The reaction is continued for 1 hour. After the reaction is completed, the temperature is cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive.

[0116] (2) Low molecular weight polyamide 650 is used as curing agent.

[0117] (3) Mix the acrylate-modified phenolic epoxy resin and the polyamide 650 curing agent in a weight ratio of 7:1 at room temperature for 0.5 h to obtain a water-resistant adhesive for later use.

[0118] 3. The preparation method of the carbon fiber skeleton layer is:

[0119] According to the weight percentage, 1 part of carbon fiber chopped fiber and 1.5 parts of calcium oxide nanoparticles are evenly dispersed in 3 parts of silicone resin AB components, stirred and mixed evenly, and then evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.1mm. Then, it is heated at 125℃ for 3h to cure it and form a carbon fiber skeleton layer.

[0120] 4. Preparation process of insulating composite materials:

[0121] The oil-resistant adhesive is applied to one side of the insulating paper layer (thickness of 0.1 mm), and after being dried in the tunnel, it is hot-pressed with the polyetheretherketone film, and then the water-resistant adhesive is applied to the other side of the polyetheretherketone film layer. After being dried in the tunnel, the carbon fiber layer is carbon fiber short fiber, adhesive, and filler. After being stirred and mixed evenly, it is evenly applied on the surface of the water-resistant adhesive layer with a thickness of 0.1 mm. Then heat it at 125 ° C for 3 hours to solidify it to form a carbon fiber skeleton layer. The surface of the carbon fiber skeleton layer is evenly coated on the water-resistant adhesive layer, and after being dried in the tunnel, it is hot-pressed with the polyetheretherketone film. The oil-resistant adhesive is applied to the other side of the polyetheretherketone film. After being dried in the tunnel, it is hot-pressed with the insulating paper layer, and finally enters the 80 ° C curing room for 12 hours to solidify the adhesive into an adhesive layer. The composite material after bonding is an insulating composite material with a structure of insulating paper layer-oil-resistant adhesive layer-polyetheretherketone film layer-water-resistant adhesive layer-carbon fiber skeleton layer-water-resistant adhesive layer-polyetheretherketone film layer-oil-resistant adhesive layer-insulating paper layer from bottom to top.

[0122] The conditions for the drying operation in the tunnel are as follows: the baking temperature is 60°C and the baking time is 40 minutes.

[0123] The hot pressing bonding conditions are as follows: hot pressing bonding temperature of 80° C., composite pressure of 0.5 MPa, and bonding time of 15 s.

[0124] Example 3

[0125] 1. Preparation of oil-resistant adhesive:

[0126] (1) According to the weight ratio, 40 parts of epoxy resin (E51) and 35 parts of butyl acetate were added to a reaction bottle according to a set ratio, and the temperature was set to 130°C. The mixture was heated and stirred to obtain a first mixture. 4.8 parts of butyl acrylate, 1.8 parts of acrylic acid, 18 parts of styrene, and 0.4 parts of benzoyl peroxide were mixed according to a ratio to obtain a second mixture. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system while stirring at the target temperature. The addition was completed within 3 hours. The reaction was continued for 4 hours, and the temperature was lowered to room temperature to obtain an acrylate-modified epoxy resin adhesive.

[0127] (2) Methyltetrahydrophthalic anhydride and 2-methylimidazole were weighed in a mass percentage of 97:3, placed in a reaction bottle, and stirred at room temperature for 30 minutes using a high-speed disperser at a stirring speed of 2000 r / min to obtain a modified anhydride curing agent.

[0128] (3) The acrylate modified epoxy resin adhesive, modified anhydride curing agent, methyl vinyl polysiloxane, iron oxide, and ethyl acetate were mixed at a weight ratio of 5:1:0.5:1:1 at room temperature for 0.5 h to obtain an oil-resistant adhesive for later use.

[0129] 2. Preparation of water-resistant adhesive:

[0130] (1) According to the weight percentage, 23 parts of bisphenol A epoxy resin (E51), 20 parts of phenolic resin and 35 parts of ethyl acetate were added to the reaction bottle according to the set ratio, the temperature was set to 130°C, and the temperature was raised while stirring to obtain a first mixture. In addition, 14 parts of benzyl methacrylate, 1 part of azobisisobutyronitrile and 13 parts of methylphenyl polysiloxane were mixed according to the ratio to obtain a second mixture. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system in the reaction bottle, and the stirring was maintained at the target temperature while adding dropwise. The addition was controlled to be complete within 3 hours, and the reaction was carried out at the target temperature for 2 hours. Then, 10 parts of silicon dioxide were added, and the reaction was continued for 1 hour. After the reaction was completed, the temperature was cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive.

[0131] (2) Low molecular weight polyamide 650 is used as curing agent.

[0132] (3) The acrylate-modified phenolic epoxy resin and the polyamide 650 curing agent were mixed at a weight ratio of 10:1 at room temperature for 0.5 h to obtain a water-resistant adhesive for later use.

[0133] 3. The preparation method of the carbon fiber skeleton layer is:

[0134] According to the weight percentage, 1 part of carbon fiber chopped fiber and 2 parts of aluminum oxide nanoparticles are evenly dispersed in 3 parts of silicone resin AB component, stirred and mixed evenly, and then evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.2mm. Then, it is heated at 115℃ for 5h to cure it and form a carbon fiber skeleton layer.

[0135] 4. Preparation process of insulating composite materials:

[0136] The oil-resistant adhesive is applied to one side of the insulating paper layer (thickness of 0.05mm), and after being dried in the tunnel, it is hot-pressed with the polyphenylene sulfide film, and then the water-resistant adhesive is applied to the other side of the polyphenylene sulfide film layer. After being dried in the tunnel, the carbon fiber layer is carbon fiber short fiber, adhesive, and filler. After being stirred and mixed evenly, it is evenly applied on the surface of the water-resistant adhesive layer with a thickness of 0.2mm. Then it is heated at 115℃ for 5h to solidify it to form a carbon fiber skeleton layer. The surface of the carbon fiber skeleton layer is evenly coated on the water-resistant adhesive layer, and after being dried in the tunnel, it is hot-pressed with the polyphenylene sulfide film. The oil-resistant adhesive is applied to the other side of the polyphenylene sulfide film. After being dried in the tunnel, it is hot-pressed with the insulating paper layer, and finally enters the 80℃ curing room for 12h to solidify the adhesive into an adhesive layer. The composite material after bonding is an insulating composite material with a structure of insulating paper layer - oil-resistant adhesive layer - polyphenylene sulfide film layer - water-resistant adhesive - carbon fiber skeleton layer - water-resistant adhesive layer - polyphenylene sulfide film layer - oil-resistant adhesive layer - insulating paper layer from bottom to top.

[0137] The conditions for the drying operation in the tunnel are as follows: the baking temperature is 80°C and the baking time is 20 minutes.

[0138] The hot pressing bonding conditions are as follows: hot pressing bonding temperature of 110° C., composite pressure of 1.2 MPa, and bonding time of 10 s.

[0139] Example 4

[0140] 1. Preparation of oil-resistant adhesive:

[0141] (1) According to the weight ratio, 50 parts of epoxy resin and 45 parts of xylene were added to a reaction bottle according to a set ratio, and the temperature was set to 125°C. The temperature was raised while stirring to obtain a first mixture. In addition, 7 parts of butyl acrylate, 4 parts of acrylic acid, 25 parts of styrene, and 0.8 parts of tert-butyl hydroperoxide were mixed according to a ratio to obtain a second mixture. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system while stirring was maintained at the target temperature. The addition was completed within 3 hours. The reaction was continued for 4 hours, and the temperature was lowered to room temperature to obtain an acrylate-modified epoxy resin adhesive.

[0142] (2) Methyltetrahydrophthalic anhydride and 2-methylimidazole were weighed in a mass percentage of 95:5, placed in a reaction bottle, and stirred at room temperature for 30 minutes using a high-speed disperser at a stirring speed of 2000 r / min to obtain a modified anhydride curing agent.

[0143] (3) The acrylate-modified epoxy resin adhesive, modified anhydride curing agent, methyl vinyl polysiloxane, sodium oxide, and ethyl acetate were mixed at a weight ratio of 10:1:0.5:2:4 at room temperature for 0.5 h to obtain an oil-resistant adhesive for later use.

[0144] 2. Preparation of water-resistant adhesive:

[0145] (1) According to the weight percentage, 23 parts of bisphenol A epoxy resin, 20 parts of phenolic resin and 35 parts of butyl acetate were added to the reaction bottle according to the set ratio, the temperature was set to 130°C, and the temperature was raised while stirring to obtain a first mixture. In addition, 10 parts of benzyl methacrylate, 1 part of benzoyl peroxide and 15 parts of methylphenyl polysiloxane were mixed according to the ratio to obtain a second mixture. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system in the reaction bottle, and the stirring was maintained at the target temperature while adding dropwise. The addition was controlled to be complete within 3 hours, and the reaction was carried out at the target temperature for 2 hours. Then, 6 parts of silica were added and the reaction was continued for 1 hour. After the reaction was completed, the temperature was cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive.

[0146] (2) Low molecular weight polyamide 650 is used as curing agent.

[0147] (3) The acrylate-modified phenolic epoxy resin adhesive and the polyamide 650 curing agent were mixed at a weight ratio of 5:1 at room temperature for 0.5 h to obtain a water-resistant adhesive for later use.

[0148] 3. The preparation method of the carbon fiber skeleton layer is:

[0149] According to the weight percentage, 1 part of carbon fiber chopped fiber and 1.5 parts of calcium oxide nanoparticles are evenly dispersed in 3 parts of silicone resin AB components, stirred and mixed evenly, and then evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.15mm. Then, it is heated at 120℃ for 5h to cure it and form a carbon fiber skeleton layer.

[0150] 4. Preparation process of insulating composite materials:

[0151] The oil-resistant adhesive is applied to one side of the insulating paper layer (thickness of 0.250 mm), and after being slightly dried in the tunnel, it is hot-pressed with the polyethylene naphthalate film, and then the water-resistant adhesive is applied to the other side of the polyethylene naphthalate film layer. After being slightly dried in the tunnel, the carbon fiber layer is carbon fiber short fibers, adhesives, and fillers. After being stirred and mixed evenly, the carbon fiber layer is evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.15 mm. Then heat it at 120 ° C for 5 hours to solidify it to form a carbon fiber skeleton layer. The surface of the carbon fiber skeleton layer is evenly coated on the water-resistant adhesive layer, and after being slightly dried in the tunnel, it is hot-pressed with the polyethylene naphthalate film. The oil-resistant adhesive is applied to the other side of the polyethylene naphthalate film. After being dried in the tunnel, it is hot-pressed with the insulating paper layer and finally placed in an 80°C curing room for 12 hours to solidify the adhesive into an adhesive layer. The laminated composite material is an insulating composite material with the structure of insulating paper layer-oil-resistant adhesive layer-polymethyl naphthalate film layer-water-resistant adhesive layer-carbon fiber skeleton layer-water-resistant adhesive layer-polymethyl naphthalate film layer-oil-resistant adhesive layer-insulating paper layer from bottom to top.

[0152] The conditions for the drying operation in the tunnel are as follows: the baking temperature is 75°C and the baking time is 35 minutes;

[0153] The hot pressing bonding conditions are as follows: hot pressing bonding temperature of 100° C., composite pressure of 0.8 MPa, and bonding time of 12 s.

[0154] Example 5

[0155] 1. Preparation of oil-resistant adhesive:

[0156] (1) According to the weight ratio, 40 parts of epoxy resin and 35 parts of butyl acetate were added to a reaction bottle according to a set ratio, and the temperature was set to 130°C. The temperature was raised while stirring to obtain a first mixture. 4.8 parts of butyl acrylate, 1.8 parts of acrylic acid, 18 parts of styrene, and 0.4 parts of tert-butyl hydroperoxide were mixed according to a ratio to obtain a second mixture. When the reaction temperature was raised to the target temperature, the second mixture was added dropwise to the first mixture system while stirring was maintained at the target temperature. The addition was completed within 3 hours. The reaction was continued for 4 hours, and the temperature was lowered to room temperature to obtain an acrylate-modified epoxy resin adhesive.

[0157] (2) Methyltetrahydrophthalic anhydride and 2-methylimidazole were weighed in a mass percentage of 96.5:3.5, respectively, and the two raw materials were placed in a reaction bottle. The mixture was stirred at room temperature for 30 minutes using a high-speed disperser at a stirring speed of 2000 r / min to obtain a modified anhydride curing agent.

[0158] (3) The acrylate-modified epoxy resin adhesive, modified anhydride curing agent, methylphenyl polysiloxane, calcium oxide, and ethyl acetate were mixed at a weight ratio of 7:1:0.2:2:4 at room temperature for 0.5 h to obtain an oil-resistant adhesive for later use.

[0159] 2. Preparation of water-resistant adhesive:

[0160] (1) According to the weight percentage, 22 parts of bisphenol A epoxy resin, 20 parts of phenolic resin and 35 parts of ethyl acetate are added to the reaction bottle according to the set ratio, the temperature is set to 125°C, and the temperature is raised while stirring to obtain a first mixture. In addition, 11 parts of benzyl methacrylate, 0.3 parts of dibenzoyl peroxide and 10 parts of methylphenyl polysiloxane are mixed according to the ratio to obtain a second mixture. When the reaction temperature rises to the target temperature, the second mixture is added dropwise to the first mixture system in the reaction bottle, and the stirring is maintained at the target temperature while adding dropwise. The addition is controlled to be complete within 3 hours, and the reaction is carried out at the target temperature for 2 hours. Then, 5 parts of silicon dioxide are added, and the reaction is continued for 1 hour. After the reaction is completed, the temperature is cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive.

[0161] (2) Low molecular weight polyamide 650 is used as curing agent.

[0162] (3) The acrylate-modified phenolic epoxy resin and the polyamide 650 curing agent were mixed at a weight ratio of 5:1 at room temperature for 0.5 h to obtain a water-resistant adhesive for later use.

[0163] 3. The preparation method of the carbon fiber skeleton layer is:

[0164] According to the weight percentage, 1 part of carbon fiber chopped fiber and 2 parts of aluminum oxide nanoparticles are evenly dispersed in 3 parts of silicone resin AB component, stirred and mixed evenly, and then evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.15mm. Then, it is heated at 120℃ for 5h to solidify and form a carbon fiber skeleton layer.

[0165] 4. Preparation process of insulating composite materials:

[0166] The oil-resistant adhesive is applied to one side of the insulating paper layer (thickness of 0.300mm), and after being slightly dried in the tunnel, it is hot-pressed with the polyimide film, and then the water-resistant adhesive is applied to the other side of the polyimide film layer. After being slightly dried in the tunnel, the carbon fiber layer is carbon fiber short fiber, adhesive, and filler. After stirring and mixing, it is evenly coated on the surface of the water-resistant adhesive layer with a thickness of 0.15mm. Then heat it at 120℃ for 5h to cure it to form a carbon fiber skeleton layer. The surface of the carbon fiber skeleton layer is evenly coated on the water-resistant adhesive layer, and after being slightly dried in the tunnel, it is hot-pressed with the polyimide film. The oil-resistant adhesive is applied to the other side of the polyimide film. After being slightly dried in the tunnel, it is hot-pressed with the insulating paper layer, and finally enters the 80℃ curing room for 12h to cure the adhesive into an adhesive layer. The composite material after bonding is an insulating composite material with a structure of insulating paper layer-oil-resistant adhesive layer-polyimide film layer-water-resistant adhesive layer-carbon fiber skeleton layer-water-resistant adhesive layer-polyimide film layer-oil-resistant adhesive layer-insulating paper layer from bottom to top.

[0167] The conditions for the drying operation in the tunnel are as follows: the baking temperature is 70°C and the baking time is 30 minutes;

[0168] The hot pressing bonding conditions are as follows: hot pressing bonding temperature of 100° C., composite pressure of 1.0 MPa, and bonding time of 12 s.

[0169] Comparative Example 1

[0170] The process conditions of this comparative example 1 are consistent with those of Example 5, except that: in this comparative example 1, no carbon fiber skeleton layer is added, and a composite material with an insulating paper layer-oil-resistant adhesive layer-polyimide film layer-water-resistant adhesive layer-polyimide film layer-oil-resistant adhesive layer-insulating paper layer structure is prepared.

[0171] Comparative Example 2

[0172] The process conditions of this comparative example 2 are consistent with those of Example 5, except that: in this comparative example 2, an oil-resistant adhesive is used instead of a water-resistant adhesive to prepare a composite material having a structure of insulating paper layer-oil-resistant adhesive layer-polyimide film layer-oil-resistant adhesive layer-carbon fiber skeleton layer-oil-resistant adhesive layer-polyimide film layer-oil-resistant adhesive layer-insulating paper layer.

[0173] Comparative Example 3

[0174] The process conditions of this comparative example 3 are consistent with those of Example 5, except that: in this comparative example 3, a water-resistant adhesive is used instead of an oil-resistant adhesive to prepare a composite material having a structure of insulating paper layer-water-resistant adhesive layer-polyimide film layer-water-resistant adhesive layer-carbon fiber skeleton layer-water-resistant adhesive layer-polyimide film layer-water-resistant adhesive layer-insulating paper layer.

[0175] Comparative Example 4

[0176] The process conditions of this comparative example 4 are consistent with those of Example 5, except that the amount of carbon fiber chopped fibers in the carbon fiber skeleton layer of this comparative example 4 is increased, and the amount of carbon fiber chopped fibers added in this comparative example 4 is 2 parts.

[0177] Comparative Example 5

[0178] The process conditions of this comparative example 5 are consistent with those of Example 5, except that the amount of carbon fiber chopped fibers in the carbon fiber skeleton layer of this comparative example 5 is reduced, and the amount of carbon fiber chopped fibers added in this comparative example 5 is 0.5 parts.

[0179] Comparative Example 6

[0180] The process conditions of Comparative Example 6 are consistent with those of Example 5, except that no filler is added to the carbon fiber skeleton layer of Comparative Example 6.

[0181] Comparative Example 7

[0182] The process conditions of this comparative example 7 are consistent with those of Example 5, except that: when preparing the carbon fiber skeleton layer in this comparative example 7, the heating temperature is lowered, and the heating temperature when preparing the carbon fiber skeleton layer in this comparative example 7 is 100°C.

[0183] Comparative Example 8

[0184] The process conditions of this comparative example 8 are consistent with those of Example 5, except that: when preparing the carbon fiber skeleton layer in this comparative example 8, the heating temperature is increased, and the heating temperature when preparing the carbon fiber skeleton layer in this comparative example 8 is 140°C.

[0185] Comparative Example 9

[0186] The process conditions of this comparative example 9 are consistent with those of Example 5, except that: when preparing the water-resistant adhesive in this comparative example 9, the number of added bisphenol A epoxy resins is reduced, and the amount of bisphenol A epoxy resins added in this comparative example 9 is 15 parts (lower than the amount specified in the present invention).

[0187] Comparative Example 10

[0188] The process conditions of this comparative example 10 are consistent with those of Example 5, except that: in this comparative example 10, when preparing the water-resistant adhesive, no silicon dioxide is added.

[0189] Comparative Example 11

[0190] The process conditions of this comparative example 11 are consistent with those of Example 5, except that: when preparing the modified anhydride curing agent in this comparative example 11, the proportion of methyltetrahydrophthalic anhydride is reduced. In this comparative example 11, methyltetrahydrophthalic anhydride and 2-methylimidazole are mixed in a ratio of 80:20.

[0191] The insulating composite materials obtained in the above examples and comparative examples were subjected to performance tests, and the specific results are shown in Table 1 below, wherein the measurement methods involved are:

[0192] Tensile strength: GB / T 5591.2-2017;

[0193] Oil and water resistance test: GB / T 17948.7-2016;

[0194] Volume resistivity test: GB / T 1410-2006;

[0195] Out-of-plane thermal conductivity: GB / T 29313-2012;

[0196] Hot adhesion: GB / T 5591.2-2017.

[0197] Table 1 Test results of insulation composite materials performance

[0198]

[0199] From the above table data, it can be seen that the insulating composite materials prepared by the preparation method of the present invention in Examples 1 to 5 are both water-resistant and oil-resistant, and have extremely strong electrical insulation, thermal conductivity, flame retardancy and mechanical strength. This makes up for the shortcomings of the existing insulating materials in terms of insufficient thermal conductivity and mechanical strength. In addition, Figure 2 is a scanning electron microscope image of the carbon fiber chopped fibers of Example 1, Figure 3 This is a scanning electron microscope image of the carbon fiber skeleton layer. Figure 2 and Figure 3 It can be seen that carbon fiber short fibers are short-cut carbon fibers, and the short carbon fibers are used as raw materials to construct Figure 3 The carbon fiber skeleton layer, from Figure 3 It can be seen that the surface of the carbon fiber skeleton layer is smooth, with tiny cracks and rough surfaces, which are conducive to the adhesion of water-resistant adhesives. Short carbon fiber fibers can be observed in the cracks, which play a supporting role in the entire structure.

[0200] From the data comparison between Comparative Example 1 and Example 5, it can be seen that the difference is that: in this Comparative Example 1, no carbon fiber skeleton layer is added, resulting in a smaller tensile strength of Comparative Example 1, which is 130 N / cm, much less than 190 N / cm of Example 5. Because the carbon fiber layer plays a skeleton support role, the structural strength of the insulating composite material can be greatly improved. At the same time, the thermal conductivity of Comparative Example 1 is also much smaller than that of Example 5. Because carbon fiber has good thermal conductivity, Comparative Example 1 does not add carbon fiber, resulting in poor thermal conductivity.

[0201] From the comparison of the data of Comparative Example 2 and Example 5, it can be seen that the insulating composite material obtained by replacing the water-resistant adhesive layer with an oil-resistant adhesive layer still has good tensile strength and high temperature resistance, but performs poorly in the oil and water resistance test.

[0202] From the comparison of the data of Comparative Example 3 and Example 5, it can be seen that the insulating composite material obtained by replacing the oil-resistant adhesive layer with a water-resistant adhesive layer has a test result that is basically the same as that of Comparative Example 2. Although the insulating composite material with only a water-resistant coating still has good tensile strength and high temperature resistance, it performs poorly in the oil and water resistance test.

[0203] From the data comparison between Comparative Example 4 and Example 5, it can be seen that the amount of carbon fiber chopped fibers in the carbon fiber skeleton layer of Comparative Example 4 is increased. The amount of carbon fiber chopped fibers added in Comparative Example 4 is 2 parts. Comparative Example 4 increases the amount of carbon fiber, resulting in the adhesive not being able to completely cover the carbon fiber, leaving the carbon fiber material exposed, affecting the insulation performance of the insulating composite material. From the data, it can be seen that the volume resistivity of Example 5 is 8.6*10 9 Ω•cm, while the volume resistivity of Comparative Example 4 is 4.7*10 9 Ω•cm, the insulation performance of comparative example 4 is much lower than that of embodiment 5, and the carbon fiber in comparative example 4 is increased to 2 parts of the original, which also seriously affects the structural strength of the insulating composite material.

[0204] From the data comparison between Comparative Example 5 and Example 5, it can be seen that the amount of carbon fiber chopped fibers is reduced in the carbon fiber skeleton layer of Comparative Example 5, and the amount of carbon fiber chopped fibers added in Comparative Example 5 is 0.5 parts. The amount of carbon fiber is reduced in Comparative Example 5, resulting in poor structural strength and thermal conductivity of the insulating composite material of Comparative Example 5, which is much lower than that of Example 5.

[0205] From the data comparison between Comparative Example 6 and Example 5, it can be seen that no filler is added to the carbon fiber skeleton layer of Comparative Example 6, and the filler plays a role in increasing the structural strength of the carbon fiber skeleton layer, making the carbon fiber skeleton layer structure more stable. From the data analysis, the tensile strength of Comparative Example 6 is 130N / cm, which is much less than 190N / cm of Example 5.

[0206] From the data comparison between Comparative Example 7 and Example 5, it can be seen that when the carbon fiber skeleton layer is prepared in Comparative Example 7, the heating temperature is lowered. When the carbon fiber skeleton layer is prepared in Comparative Example 7, the heating temperature is 100°C. The reaction temperature is too low, resulting in the adhesive of the carbon fiber skeleton layer not being completely bonded and fixing the carbon fiber, resulting in poor structural strength of the carbon fiber skeleton layer, and affecting the insulation properties of the insulating composite material.

[0207] From the data comparison between Comparative Example 8 and Example 5, it can be seen that when the carbon fiber skeleton layer is prepared in Comparative Example 8, the heating temperature is increased, and the heating temperature when the carbon fiber skeleton layer is prepared in Comparative Example 8 is 140° C. The reaction temperature is too high, resulting in the volatilization of the low-boiling point volatile components in the adhesive component, reducing the bonding strength of the adhesive, resulting in poor structural strength of the carbon fiber skeleton layer, and affecting the insulation performance of the insulating composite material.

[0208] From the data comparison between Comparative Example 9 and Example 5, it can be seen that the insulating composite material prepared after reducing the epoxy resin content in the water-resistant adhesive has poor tensile strength and heat resistance test results. This is because the epoxy group content of the epoxy resin directly affects the cross-linking density of the modified phenolic resin. A low epoxy resin content will lead to a decrease in the cross-linking density, thereby affecting the mechanical strength and heat resistance of the material. Moreover, a decrease in the epoxy group content will also limit the subsequent curing reaction process. Therefore, the prepared insulating composite material water-resistant adhesive layer does not have good adhesion, is prone to stratification in the heat resistance test, and has a significantly reduced tensile strength.

[0209] From the comparison of the data of Comparative Example 10 and Example 5, it can be seen that when silica is not added in the process of preparing the water-resistant adhesive, the prepared insulating composite material exhibits poor heat resistance, thermal conductivity and mechanical properties, and a higher curing temperature is required in the preparation process. This is because silica has the characteristics of small particle size, large specific surface area and high surface activity, so it can form a high bonding force with acrylate-modified phenolic epoxy resin when used in water-resistant adhesives. At the same time, silica can also improve the heat resistance, fire resistance and waterproof performance of water-resistant adhesives to a certain extent.

[0210] From the comparison of the data of Comparative Example 11 and Example 5, it can be seen that when the content of the accelerator 2-methylimidazole is too high, the tensile strength and heat resistance of the prepared insulating composite material will deteriorate. This is because too much accelerator may cause the curing reaction to be too rapid, making it impossible for the epoxy groups in the epoxy resin to fully react, thereby affecting the bonding between the film and the aramid paper layer, resulting in stratification during the subsequent heat resistance test, which in turn affects the final performance of the insulating composite material.

[0211] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are exhaustively listed. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0212] For those skilled in the art, several modifications and improvements may be made without departing from the concept of the present invention, all of which belong to the protection scope of the present invention. The protection scope of the present invention shall be based on the attached claims.

Claims

1. An insulating composite material containing a carbon fiber skeleton, characterized in that: The composite material comprises a carbon fiber skeleton layer, and two sides of the carbon fiber skeleton layer are sequentially provided with a water-resistant adhesive layer, an anti-permeation film layer, an oil-resistant adhesive layer and an insulating paper layer outwardly; In terms of weight, the carbon fiber skeleton layer includes 1 part of carbon fiber chopped fibers, 1.5-2 parts of fillers, and 3-3.5 parts of adhesives; The preparation method of the carbon fiber skeleton layer is as follows: after the carbon fiber chopped fibers and the filler are uniformly dispersed in the adhesive, the carbon fiber skeleton layer is formed by coating and heating and curing, the coating thickness is 0.1-0.2 mm, the heating and curing temperature is 115-125° C., and the heating and curing time is 3-5 hours; The water-resistant adhesive layer is prepared by coating a water-resistant adhesive composed of an acrylate-modified phenolic epoxy resin adhesive and a curing agent, wherein the acrylate-modified phenolic epoxy resin adhesive comprises 20-30 parts of bisphenol A epoxy resin, 15-25 parts of phenolic resin, 30-40 parts of an organic solvent, 10-15 parts of a benzyl methacrylate monomer, 0.3-3 parts of an initiator, 10-15 parts of a polysiloxane compound, and 5-10 parts of silicon dioxide; the curing agent used in the water-resistant adhesive layer is polyamide 650; The oil-resistant adhesive layer is prepared by coating an oil-resistant adhesive composed of an acrylate-modified epoxy resin adhesive, a modified acid anhydride curing agent, a polysiloxane compound, a metal oxide, and an organic solvent; the modified acid anhydride curing agent includes a phthalic anhydride compound and an imidazole accelerator, and in the modified acid anhydride curing agent, the mass ratio of the phthalic anhydride compound to the imidazole accelerator is (89-97%):(3-11%); The preparation method of the acrylate modified phenolic epoxy resin adhesive is: The bisphenol A epoxy resin, the phenolic resin and the organic solvent are uniformly mixed to obtain a first mixture; the benzyl methacrylate monomer, the initiator and the polysiloxane compound are uniformly mixed to obtain a second mixture; the second mixture is added dropwise to the first mixture at 110-130° C., the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and then silicon dioxide is added, the reaction is continued for 0.5-1 hour, and after the reaction is completed, the temperature is cooled to room temperature to obtain an acrylate-modified phenolic epoxy resin adhesive; The benzyl methacrylate monomer is any one of butyl acrylate, ethyl acrylate and methyl acrylate; The organic solvent used in preparing the acrylate-modified phenolic epoxy resin adhesive is ethyl acetate, butyl acetate or xylene; The initiator used in preparing the acrylate-modified phenolic epoxy resin adhesive is azobisisobutyronitrile, dibenzoyl peroxide or benzoyl peroxide; The preparation method of the acrylate modified epoxy resin adhesive is as follows: according to weight parts, 30-60 parts of epoxy resin and 30-60 parts of solvent are mixed evenly to obtain a first mixture; 3-7 parts of acrylate monomer, 1-5 parts of acrylic acid, 10-30 parts of styrene, and 0.1-1 parts of initiator are mixed evenly to obtain a second mixture; under the condition of 110-140° C., the second mixture is added dropwise to the first mixture, the addition is controlled to be complete within 2-5 hours, the reaction is continued for 2-5 hours, and the temperature is lowered to room temperature to obtain the acrylate modified epoxy resin adhesive; The solvent used in preparing the acrylate-modified epoxy resin adhesive is ethyl acetate, butyl acetate or xylene; The initiator used in preparing the acrylate-modified epoxy resin adhesive is benzoyl peroxide or tert-butyl hydroperoxide.

2. The insulating composite material containing a carbon fiber skeleton according to claim 1, characterized in that: The anti-permeation film layer is selected from any one of a polyimide film, a polyethylene naphthalate film, a polyphenylene sulfide film, and a polyetheretherketone film; The insulating paper layer is selected from meta-aramid staple fiber paper with a thickness of 0.04 mm, 0.05 mm, 0.1 mm, 0.250 mm or 0.300 mm.

3. The insulating composite material containing a carbon fiber skeleton according to claim 1, characterized in that: In the carbon fiber skeleton layer, the filler is aluminum oxide nanoparticles or calcium oxide nanoparticles; the adhesive is an organic silicone resin AB component, component A in the organic silicone resin AB component includes methyl methacrylate, formaldehyde and pyridine, and component B in the organic silicone resin AB component includes aniline, modified polyamine, amino polyammonium acid and methylphenyl polysiloxane; the carbon fiber chopped fibers have a length of 1-3 mm and a diameter of 20-100 μm.

4. The insulating composite material containing a carbon fiber skeleton according to claim 1, characterized in that: When the water-resistant adhesive is used, the acrylate-modified phenolic epoxy resin adhesive and the curing agent are mixed evenly in a weight ratio of (5-10):1 and then coated.

5. The insulating composite material containing a carbon fiber skeleton according to claim 1, characterized in that: When the oil-resistant adhesive is used, the acrylate-modified epoxy resin, the modified acid anhydride curing agent, the vinyl silicone oil, the metal oxide, and the organic solvent are mixed evenly in a weight ratio of (5-10): 1: (0.2-0.5): (1-2): (1-4) and then applied; The metal oxide is any one of aluminum oxide, calcium oxide, sodium oxide, and iron oxide; The organic solvent is ethyl acetate, butyl acetate or xylene.

6. A method for preparing an insulating composite material containing a carbon fiber skeleton according to any one of claims 1 to 5, characterized in that: The preparation method is: S1. Apply oil-resistant adhesive on one side of the insulating paper layer, bake it in the tunnel, and then hot-press and bond it with the anti-permeation film layer; S2, coating a water-resistant adhesive on the other side of the anti-permeation film layer in step S1, and after baking in the tunnel, evenly coating a mixture of carbon fiber staple fibers, adhesive and filler on the water-resistant adhesive layer, and then heating and curing at 115-125° C. for 3-5 hours to form a carbon fiber skeleton layer; S3, evenly coating the surface of the carbon fiber skeleton layer with a water-resistant adhesive, baking it in a tunnel, and then hot-pressing and laminating it with the anti-permeation film layer; S4, coating the other side of the anti-permeation film layer in step S3 with an oil-resistant adhesive, baking it in a tunnel, and then hot-pressing and laminating it with the insulating paper layer; S5, performing a aging treatment to obtain the insulating composite material.

7. The method for preparing an insulating composite material containing a carbon fiber skeleton according to claim 6, characterized in that: In steps S1-S4, the tunnel baking conditions are: baking temperature 60-80°C, baking time 20-40min; In steps S1-S4, the hot pressing bonding conditions are: hot pressing bonding temperature 80-110°C, composite pressure 0.5-1.2MPa, and bonding time 10-15s; In step S5, the aging treatment conditions are: aging temperature is 75-85°C, and aging time is 10-12h.

8. An application of an insulating composite material containing a carbon fiber skeleton according to any one of claims 1 to 5, characterized in that: The insulating composite material is used as an interface insulating heat-conducting and filling material between electronic components and heat sinks.

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