Two-component polyurethane heat-conducting structural adhesive and preparation method thereof

Abstract

The invention discloses a two-component polyurethane heat-conducting structural adhesive and a preparation method thereof, and relates to the technical field of polyurethane heat-conducting structural adhesives. The coating comprises a component A and a component B, the component A is prepared from the following components in parts by mass: 40 to 50 parts of modified polycarbonate polyol, 30 to 40 parts of modified polyether polyol, 15 to 25 parts of modified aluminum oxide filler and 1 to 3 parts of silane coupling agent; the modified polycarbonate polyol is obtained by adding 2-sulfonic terephthalic acid and a first catalyst into polycarbonate polyol; the modified polyether polyol is obtained by adding 3-phenylpropionic acid p-nitrophenyl ester and a second catalyst into polyether polyol; the modified aluminum oxide filler is obtained by adding an aluminum oxide filler into potassium perfluorooctane sulfonate; the component B is prepared from the following components in parts by mass: 20 to 30 parts of diphenylmethane diisocyanate, 40 to 50 parts of modified polycarbonate polyol, 1 to 3 parts of a dewatering agent and 20 to 30 parts of modified aluminum oxide filler. The two-component polyurethane heat-conducting structural adhesive prepared by the invention has better flexibility and impact resistance, and the stability of the two-component polyurethane heat-conducting structural adhesive is improved.

Description

Technical Field

[0001] The invention relates to the technical field of polyurethane thermal conductive structural adhesive, in particular to a two-component polyurethane thermal conductive structural adhesive and a preparation method thereof. Background Art

[0002] Soft-pack batteries are currently widely used in new energy vehicles due to their safety, light weight, high capacity, low internal resistance, adaptable shape, and flexible design. The assembly process for soft-pack batteries primarily involves attaching the battery to an aluminum plate using structural adhesive. Commonly used thermally conductive structural adhesives for soft-pack batteries include two-component polyurethane thermally conductive structural adhesives, one-component silicone, and two-component silicone. One-component silicone offers the advantages of easy application and excellent adhesion, but its maximum cure depth is limited to approximately 6mm. When applied to large areas, it can experience slow internal curing or even no cure, leading to safety hazards such as poor adhesion and detachment. While two-component silicone can address this internal curing issue, it is more expensive and requires specialized adhesive application equipment. Furthermore, silicone itself has a relatively low bond strength, typically around 1-3 MPa. This can create significant impact forces during vehicle operation, potentially causing collisions. The two-component polyurethane thermal conductive structural adhesive used for bonding power battery cells generally has a strength of more than 7MPa, and the polyurethane thermal conductive structural adhesive has good toughness. It can effectively absorb and buffer the impact force during collisions and impacts, thereby effectively protecting the battery and improving safety performance.

[0003] Power batteries release a large amount of heat during charging and discharging. While battery boxes typically have heat dissipation devices, the normal operating temperature of the battery still reaches around 40-60°C. For conventional polyurethane thermally conductive structural adhesives, prolonged exposure to heat can degrade their stability, resulting in lower tensile strength and elongation at break. Therefore, there is an urgent need for a two-component polyurethane thermally conductive structural adhesive to improve its stability. Summary of the Invention

[0004] The object of the present invention is to provide a two-component polyurethane thermal conductive structural adhesive and a preparation method thereof, so as to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a two-component polyurethane thermal conductive structural adhesive, comprising component A and component B, wherein component A comprises, by mass: 40-50 parts of modified polycarbonate polyol, 30-40 parts of modified polyether polyol, 15-25 parts of modified alumina filler, and 1-3 parts of silane coupling agent; The modified polycarbonate polyol is obtained by adding 2-sulfonated terephthalic acid and a first catalyst to the polycarbonate polyol; the modified polyether polyol is obtained by adding 3-nitrophenyl phenylpropionate and a second catalyst to the polyether polyol; the modified alumina filler is obtained by adding an alumina filler to potassium perfluorooctane sulfonate; The component B comprises, by mass, 20-30 parts of diphenylmethane diisocyanate, 40-50 parts of modified polycarbonate polyol, 1-3 parts of a water remover and 20-30 parts of a modified alumina filler.

[0006] Furthermore, the particle size of the alumina filler is 5-10 microns.

[0007] Furthermore, the first catalyst includes tetrabutyl titanate, p-toluenesulfonic acid or stannous octoate.

[0008] Furthermore, the second catalyst includes p-toluenesulfonic acid or stannous octoate.

[0009] Furthermore, the mass ratio of component A to component B is (0.8-1.2):1.

[0010] Furthermore, a method for preparing a two-component polyurethane thermal conductive structural adhesive includes the following preparation steps: (1) First, heat the polycarbonate polyol to 100-120°C, vacuum dehydrate for 1-2 hours, then cool to 80-90°C, add 2-sulfonate terephthalic acid at a mass ratio of polycarbonate polyol to 2-sulfonate terephthalic acid of 100:(5-10), and then add a first catalyst of 0.1%-0.5% of the total mass of the polycarbonate polyol and 2-sulfonate terephthalic acid, stir at 300-400 r / min for 3-5 hours under the protection of nitrogen, and then cool to room temperature to obtain a modified polycarbonate polyol; (2) heating the polyether polyol to 110-130°C, vacuum dehydrating for 1-3 hours, then cooling to 90-100°C, adding 3-nitrophenyl propionate at a mass ratio of polyether polyol to 3-nitrophenyl propionate of 100:(8-15), and then adding a second catalyst in an amount of 0.1%-0.5% of the total mass of the polyether polyol and 3-nitrophenyl propionate, stirring at 300-400 r / min for 4-6 hours under nitrogen protection, and then cooling to room temperature to obtain a modified polyether polyol; (3) N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride and toluene are mixed in a mass ratio of 1:(20-50), and then appropriate amounts of deionized water and acetic acid are added, the pH value is adjusted to 4-5, and stirred at 200-300 r / min for 0.5-1 hour to obtain N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution; alumina filler and N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution are mixed in a mass ratio of 1:(10 -20) and stirred at 300-500 r / min for 2-4 hours at 50-80°C, then washed with an organic solvent 2-3 times and dried at 80-100°C for 4-6 hours to obtain a hydrophobized alumina filler; adding a potassium perfluorooctane sulfonate solution at a mass ratio of alumina filler to potassium perfluorooctane sulfonate of 100:(2-5), stirring at 300-400 r / min for 2-3 hours, and then drying at 120-150°C for 3-5 hours to obtain a modified alumina filler; (4) The modified polycarbonate polyol obtained in step (1), the modified polyether polyol obtained in step (2), the modified alumina filler obtained in step (3) and the silane coupling agent are mixed in a mass ratio of (40-50): (30-40): (15-25): (1-3), and the modified polycarbonate polyol and the modified polyether polyol are stirred at 300-400 r / min for 1-2 hours at 60-80°C, and then the modified alumina filler is added and the stirring is continued for 1-2 hours, and finally the silane coupling agent is added and stirred for 0.5-1 hour to obtain component A; diphenylmethane diisocyanate, the modified polyether polyol obtained in step (1) and the modified alumina filler are mixed and stirred at 300-400 r / min for 1-2 hours. The mass ratio of the polycarbonate polyol, the water scavenger and the modified alumina filler is (20-30): (40-50): (1-3): (20-30). The modified polycarbonate polyol is first heated to 60-80°C and vacuum dehydrated for 1-2 hours. Subsequently, diphenylmethane diisocyanate is added and reacted at 70-90°C for 2-3 hours. The water scavenger is then added and stirred at 300-400 r / min for 0.5-1 hour. Finally, the modified alumina filler is added and stirred for 1-2 hours to obtain component B. The components A and B are mixed in a mass ratio of (0.8-1.2): 1 to obtain a two-component polyurethane thermal conductive structural adhesive.

[0011] Furthermore, in the step (3), the preparation process of the potassium perfluorooctane sulfonate solution is: mixing potassium perfluorooctane sulfonate and tetrahydrofuran in a mass ratio of 1:10.

[0012] Furthermore, in the step (4), the mass ratio of the modified polycarbonate polyol, the modified polyether polyol, the modified alumina filler and the silane coupling agent is preferably 45:35:20:2.

[0013] Furthermore, in the step (4), the mass ratio of diphenylmethane diisocyanate, modified polycarbonate polyol, water scavenger and modified alumina filler is preferably 25:45:2:25.

[0014] Furthermore, the mass ratio of component A to component B is preferably 1:1.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: In the present invention, component A is composed of modified polyether polyol, modified polycarbonate polyol, modified alumina filler, and silane coupling agent; component B is prepared from diphenylmethane diisocyanate, modified polycarbonate polyol, a water scavenger, and modified alumina filler; components A and B are compounded to obtain a two-component thermally conductive structural adhesive with high stability and heat resistance.

[0016] (1) 2-sulfonated terephthalic acid and a first catalyst are added to polycarbonate polyol to obtain a modified polycarbonate polyol. The introduction of 2-sulfonated terephthalic acid increases the rigidity of the molecular chain, making the thermal conductive structural adhesive less prone to deformation and softening, while also improving heat resistance. In addition, the sulfonic acid group can increase affinity and adhesion, significantly improving the bonding performance of the two-component polyurethane thermal conductive structural adhesive and enabling reliable bonding between different materials.

[0017] Adding p-nitrophenyl 3-phenylpropionate and a second catalyst to a polyether polyol produces a modified polyether polyol. The rigidity of the benzene ring structure in p-nitrophenyl 3-phenylpropionate, combined with the flexibility of its ester group and alkyl chain, enhances the strength of the modified polyether polyol while also providing improved flexibility and impact resistance, thereby enhancing the stability of the two-component thermally conductive structural adhesive.

[0018] (2) The modified alumina filler is obtained by adding potassium perfluorooctane sulfonate to the alumina filler, which allows the sulfonate group to be adsorbed on the surface of the alumina filler, with the perfluorooctane group facing the surrounding medium, thereby reducing the surface energy of the alumina filler and reducing the attraction between particles. At the same time, a protective film is formed on the surface of the particles to prevent the particles from agglomerating, thereby improving the dispersion performance and enhancing the thermal conductivity. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0020] In order to more clearly illustrate the method provided by the present invention, the following examples are described in detail: Example 1 (1) Polycarbonate diol with a molecular weight of 3000 was first heated to 120°C, vacuum dehydrated for 1 hour, and then cooled to 80°C. 2-sulfonated terephthalic acid was added at a mass ratio of polycarbonate diol to 2-sulfonated terephthalic acid of 100:8, and then 0.2% of p-toluenesulfonic acid based on the total mass of polycarbonate diol and 2-sulfonated terephthalic acid was added. The mixture was stirred at 400 r / min for 3 hours under the protection of nitrogen, and then cooled to room temperature to obtain modified polycarbonate diol. (2) Trimethylolpropane polyether with a molecular weight of 4000 was heated to 110°C, vacuum dehydrated for 3 hours, and then cooled to 90°C. 3-nitrophenyl phenylpropionate was added at a mass ratio of 100:10 between trimethylolpropane polyether and 3-nitrophenyl phenylpropionate, and then 0.2% of p-toluenesulfonic acid based on the total mass of trimethylolpropane polyether and 3-nitrophenyl phenylpropionate was added. The mixture was stirred at 300 r / min for 6 hours under the protection of nitrogen and then cooled to room temperature to obtain modified trimethylolpropane polyether. (3) mixing potassium perfluorooctane sulfonate and tetrahydrofuran in a mass ratio of 1:10 to obtain a potassium perfluorooctane sulfonate solution; (4) N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride and toluene were mixed in a mass ratio of 1:40, and then appropriate amounts of deionized water and acetic acid were added, the pH value was adjusted to 5, and the mixture was stirred at 300 r / min for 1 hour to obtain N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution; alumina filler with a particle size of 5 mm was mixed with N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution in a mass ratio of 1:20, stirred at 500 r / min at 80°C for 3 hours, then washed with acetone three times, and dried at 100°C for 6 hours to obtain a hydrophobized alumina filler; potassium perfluorooctane sulfonate solution was added at a mass ratio of alumina filler to potassium perfluorooctane sulfonate of 100:3, stirred at 300 r / min for 3 hours, and then dried at 120°C for 5 hours to obtain a modified alumina filler; (5) The modified polycarbonate diol obtained in step (1), the modified trimethylolpropane polyether obtained in step (2), the modified alumina filler obtained in step (4) and γ-aminopropyltriethoxysilane are mixed in a mass ratio of 40:30:15:2, stirred at 400 r / min at 60°C for 2 hours, then the modified alumina filler is added, and the stirring is continued for 2 hours, and finally γ-aminopropyltriethoxysilane is added and stirred for 1 hour to obtain component A; diphenylmethane diisocyanate is used as the raw material for the preparation of the raw material. The mass ratio of ester, modified polycarbonate diol obtained in step (1), anhydrous magnesium sulfate and modified alumina filler is 20:40:1:20. The modified polycarbonate diol is first heated to 80°C and vacuum dehydrated for 2 hours. Then, diphenylmethane diisocyanate is added and reacted at 70°C for 3 hours. Anhydrous magnesium sulfate is then added and stirred at 400 r / min for 1 hour. Finally, the modified alumina filler is added and stirred for 2 hours to obtain component B. Component A and component B are mixed in a mass ratio of 0.8:1 to obtain a two-component polyurethane thermal conductive structural adhesive.

[0021] Example 2 (1) Polycarbonate diol with a molecular weight of 3000 was first heated to 120°C, vacuum dehydrated for 1 hour, and then cooled to 80°C. 2-sulfonated terephthalic acid was added at a mass ratio of polycarbonate diol to 2-sulfonated terephthalic acid of 100:8, and then 0.2% of p-toluenesulfonic acid based on the total mass of polycarbonate diol and 2-sulfonated terephthalic acid was added. The mixture was stirred at 400 r / min for 3 hours under the protection of nitrogen, and then cooled to room temperature to obtain modified polycarbonate diol. (2) Trimethylolpropane polyether with a molecular weight of 4000 was heated to 110°C, vacuum dehydrated for 3 hours, and then cooled to 90°C. 3-nitrophenyl phenylpropionate was added at a mass ratio of 100:10 between trimethylolpropane polyether and 3-nitrophenyl phenylpropionate, and then 0.2% of p-toluenesulfonic acid based on the total mass of trimethylolpropane polyether and 3-nitrophenyl phenylpropionate was added. The mixture was stirred at 300 r / min for 6 hours under the protection of nitrogen and then cooled to room temperature to obtain modified trimethylolpropane polyether. (3) mixing potassium perfluorooctane sulfonate and tetrahydrofuran in a mass ratio of 1:10 to obtain a potassium perfluorooctane sulfonate solution; (4) N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride and toluene were mixed in a mass ratio of 1:40, and then appropriate amounts of deionized water and acetic acid were added, the pH value was adjusted to 5, and the mixture was stirred at 300 r / min for 1 hour to obtain N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution; alumina filler with a particle size of 5 mm was mixed with N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution in a mass ratio of 1:20, stirred at 500 r / min at 80°C for 3 hours, then washed with acetone three times, and dried at 100°C for 6 hours to obtain a hydrophobized alumina filler; potassium perfluorooctane sulfonate solution was added at a mass ratio of alumina filler to potassium perfluorooctane sulfonate of 100:3, stirred at 300 r / min for 3 hours, and then dried at 120°C for 5 hours to obtain a modified alumina filler; (5) The modified polycarbonate diol obtained in step (1), the modified trimethylolpropane polyether obtained in step (2), the modified alumina filler obtained in step (4) and γ-aminopropyltriethoxysilane are mixed in a mass ratio of 45:35:15:2, and stirred at 400 r / min at 60°C for 2 hours, then the modified alumina filler is added, and the stirring is continued for 2 hours, and finally γ-aminopropyltriethoxysilane is added and stirred for 1 hour to obtain component A; diphenylmethane diisocyanate is added to obtain component A; The mass ratio of cyanate, modified polycarbonate diol obtained in step (1), anhydrous magnesium sulfate and modified alumina filler is 25:45:2:20. The modified polycarbonate diol is first heated to 80°C and vacuum dehydrated for 2 hours. Then, diphenylmethane diisocyanate is added and reacted at 70°C for 3 hours. Anhydrous magnesium sulfate is then added and stirred at 400 r / min for 1 hour. Finally, the modified alumina filler is added and stirred for 2 hours to obtain component B. Component A and component B are mixed in a mass ratio of 1:1 to obtain a two-component polyurethane thermal conductive structural adhesive.

[0022] Example 3 (1) Polycarbonate diol with a molecular weight of 3000 was first heated to 120°C, vacuum dehydrated for 1 hour, and then cooled to 80°C. 2-sulfonated terephthalic acid was added at a mass ratio of polycarbonate diol to 2-sulfonated terephthalic acid of 100:8, and then 0.2% of p-toluenesulfonic acid based on the total mass of polycarbonate diol and 2-sulfonated terephthalic acid was added. The mixture was stirred at 400 r / min for 3 hours under the protection of nitrogen, and then cooled to room temperature to obtain modified polycarbonate diol. (2) Trimethylolpropane polyether with a molecular weight of 4000 was heated to 110°C, vacuum dehydrated for 3 hours, and then cooled to 90°C. 3-nitrophenyl phenylpropionate was added at a mass ratio of 100:10 between trimethylolpropane polyether and 3-nitrophenyl phenylpropionate, and then 0.2% of p-toluenesulfonic acid based on the total mass of trimethylolpropane polyether and 3-nitrophenyl phenylpropionate was added. The mixture was stirred at 300 r / min for 6 hours under the protection of nitrogen and then cooled to room temperature to obtain modified trimethylolpropane polyether. (3) mixing potassium perfluorooctane sulfonate and tetrahydrofuran in a mass ratio of 1:10 to obtain a potassium perfluorooctane sulfonate solution; (4) N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride and toluene were mixed in a mass ratio of 1:40, and then appropriate amounts of deionized water and acetic acid were added, the pH value was adjusted to 5, and the mixture was stirred at 300 r / min for 1 hour to obtain N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution; alumina filler with a particle size of 5 mm was mixed with N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution in a mass ratio of 1:20, stirred at 500 r / min at 80°C for 3 hours, then washed with acetone three times, and dried at 100°C for 6 hours to obtain a hydrophobized alumina filler; potassium perfluorooctane sulfonate solution was added at a mass ratio of alumina filler to potassium perfluorooctane sulfonate of 100:3, stirred at 300 r / min for 3 hours, and then dried at 120°C for 5 hours to obtain a modified alumina filler; (5) The modified polycarbonate diol obtained in step (1), the modified trimethylolpropane polyether obtained in step (2), the modified alumina filler obtained in step (4) and γ-aminopropyltriethoxysilane are mixed in a mass ratio of 50:40:15:2, stirred at 400 r / min at 60°C for 2 hours, then the modified alumina filler is added, and the stirring is continued for 2 hours, and finally γ-aminopropyltriethoxysilane is added and stirred for 1 hour to obtain component A; diphenylmethane diisocyanate is prepared by mixing the modified polycarbonate diol and the modified trimethylolpropane polyether. The mass ratio of ester, modified polycarbonate diol obtained in step (1), anhydrous magnesium sulfate and modified alumina filler is 30:50:3:20. The modified polycarbonate diol is first heated to 80°C and vacuum dehydrated for 2 hours. Then, diphenylmethane diisocyanate is added and reacted at 70°C for 3 hours. Anhydrous magnesium sulfate is then added and stirred at 400 r / min for 1 hour. Finally, the modified alumina filler is added and stirred for 2 hours to obtain component B. Component A and component B are mixed in a mass ratio of 1.2:1 to obtain a two-component polyurethane thermal conductive structural adhesive.

[0023] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that 2-sulfonated terephthalic acid is not added, and step (5) is changed to: the mass ratio of polycarbonate diol with a molecular weight of 3000, the modified trimethylolpropane polyether obtained in step (2), the modified alumina filler obtained in step (4) and γ-aminopropyltriethoxysilane is 40:30:15:2, the polycarbonate diol and the modified trimethylolpropane polyether are first mixed, and stirred at 400r / min at 60°C for 2 hours, then the modified alumina filler is added, and stirring is continued for 2 hours, and finally γ-aminopropyltriethoxysilane is added and stirred for 1 hour to obtain A Components: diphenylmethane diisocyanate, polycarbonate diol with a molecular weight of 3000, anhydrous magnesium sulfate and modified alumina filler are mixed in a mass ratio of 20:40:1:20, the polycarbonate diol is first heated to 80°C and vacuum dehydrated for 2 hours, then diphenylmethane diisocyanate is added, and the mixture is reacted at 70°C for 3 hours, anhydrous magnesium sulfate is added, and stirred at 400r / min for 1 hour, and finally the modified alumina filler is added and stirred for 2 hours to obtain component B; component A and component B are mixed in a mass ratio of 0.8:1 to obtain a two-component polyurethane thermal conductive structural adhesive, and the other steps are the same as in Example 1.

[0024] Comparative Example 2: The difference between Comparative Example 2 and Example 1 is that ordinary trimethylolpropane polyether with a molecular weight of 4000 is used instead of the modified trimethylolpropane polyether, and the other steps are the same as Example 1.

[0025] Comparative Example 3: The difference between Comparative Example 3 and Example 3 is that ordinary alumina filler with a particle size of 5 mm is used instead of the modified alumina filler, and the other steps are the same as Example 1.

[0026] Performance Testing 1. Thermal conductivity test: The test was conducted in accordance with ISO 22007-2. Component A and component B of Examples 1-3 and Comparative Examples 1-3 were mixed at a mass ratio of 1:1. The uniformly mixed adhesive was formed into a test block having a side length of not less than 36 mm and a thickness of not less than 6 mm. The test block was cured for 7 days at a temperature of 23° C. and a humidity of 50%, and then tested using a Hot Disk thermal constant analyzer.

[0027] 2. Tensile strength and elongation at break test: The test was conducted in accordance with GB / T 528-2009. Component A and component B of Examples 1-3 and Comparative Examples 1-3 were mixed in a mass ratio of 1:1 and placed in a vulcanizer flat mold (20*20*0.2 cm). After curing for 7 days at 23°C and 50% humidity, standard specimens were cut out with a Type I cutter and tensile tested using a universal testing machine at a tensile speed of 10 mm / min.

[0028] 3. Rotational viscosity test: According to GB / T 2794-2013 standard, a No. 14 rotor was used at a speed of 50 RPM to test the polyurethane two-component thermal conductive structural adhesive samples obtained in Examples 1-3 and Comparative Examples 1-3.

[0029] Table 1 below shows the performance analysis results of Examples 1 to 3 of the present invention and Comparative Examples 1 to 3.

[0030] Table 1

[0031] As can be seen from Table 1, the addition of modified polycarbonate polyol, modified polyether polyol, and modified alumina filler significantly improves the bonding performance of the two-component polyurethane thermally conductive structural adhesive, enabling reliable bonding between different materials. It also provides better flexibility and impact resistance, and can improve the stability of the two-component thermally conductive structural adhesive.

[0032] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A two-component polyurethane thermal conductive structural adhesive, comprising component A and component B, characterized in that: The component A comprises, by mass, 40-50 parts of modified polycarbonate polyol, 30-40 parts of modified polyether polyol, 15-25 parts of modified alumina filler and 1-3 parts of silane coupling agent; The modified polycarbonate polyol is obtained by adding 2-sulfonated terephthalic acid and a first catalyst to the polycarbonate polyol; the modified polyether polyol is obtained by adding 3-nitrophenyl phenylpropionate and a second catalyst to the polyether polyol; the modified alumina filler is obtained by adding an alumina filler to potassium perfluorooctane sulfonate; The component B comprises, by mass, 20-30 parts of diphenylmethane diisocyanate, 40-50 parts of modified polycarbonate polyol, 1-3 parts of a water remover and 20-30 parts of a modified alumina filler.

2. The two-component polyurethane thermal conductive structural adhesive according to claim 1, characterized in that: The particle size of the alumina filler is 5-10 microns.

3. The two-component polyurethane thermal conductive structural adhesive according to claim 1, characterized in that: The first catalyst includes tetrabutyl titanate, p-toluenesulfonic acid or stannous octoate.

4. The two-component polyurethane thermal conductive structural adhesive according to claim 1, characterized in that: The second catalyst includes p-toluenesulfonic acid or stannous octoate.

5. The two-component polyurethane thermal conductive structural adhesive according to claim 4, characterized in that: The mass ratio of component A to component B is (0.8-1.2):

1.

6. A method for preparing a two-component polyurethane thermal conductive structural adhesive, characterized in that: The method comprises the following preparation steps: (1) First, heat the polycarbonate polyol to 100-120°C, vacuum dehydrate for 1-2 hours, then cool to 80-90°C, add 2-sulfonate terephthalic acid at a mass ratio of polycarbonate polyol to 2-sulfonate terephthalic acid of 100:(5-10), and then add a first catalyst of 0.1%-0.5% of the total mass of the polycarbonate polyol and 2-sulfonate terephthalic acid, stir at 300-400 r / min for 3-5 hours under the protection of nitrogen, and then cool to room temperature to obtain a modified polycarbonate polyol; (2) heating the polyether polyol to 110-130°C, vacuum dehydrating for 1-3 hours, then cooling to 90-100°C, adding 3-nitrophenyl propionate at a mass ratio of polyether polyol to 3-nitrophenyl propionate of 100:(8-15), and then adding a second catalyst in an amount of 0.1%-0.5% of the total mass of the polyether polyol and 3-nitrophenyl propionate, stirring at 300-400 r / min for 4-6 hours under nitrogen protection, and then cooling to room temperature to obtain a modified polyether polyol; (3) N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride and toluene are mixed in a mass ratio of 1:(20-50), and then appropriate amounts of deionized water and acetic acid are added, the pH value is adjusted to 4-5, and stirred at 200-300 r / min for 0.5-1 hour to obtain N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution; alumina filler and N-trimethoxysilylpropyl-N,N,N-tri-n-butylammonium chloride solution are mixed in a mass ratio of 1:(10 -20) and stirred at 300-500 r / min for 2-4 hours at 50-80°C, then washed with an organic solvent 2-3 times and dried at 80-100°C for 4-6 hours to obtain a hydrophobized alumina filler; adding a potassium perfluorooctane sulfonate solution at a mass ratio of alumina filler to potassium perfluorooctane sulfonate of 100:(2-5), stirring at 300-400 r / min for 2-3 hours, and then drying at 120-150°C for 3-5 hours to obtain a modified alumina filler; (4) The modified polycarbonate polyol obtained in step (1), the modified polyether polyol obtained in step (2), the modified alumina filler obtained in step (3) and the silane coupling agent are mixed in a mass ratio of (40-50): (30-40): (15-25): (1-3), and the modified polycarbonate polyol and the modified polyether polyol are stirred at 300-400 r / min for 1-2 hours at 60-80°C, and then the modified alumina filler is added and the stirring is continued for 1-2 hours, and finally the silane coupling agent is added and stirred for 0.5-1 hour to obtain component A; diphenylmethane diisocyanate, the modified polyether polyol obtained in step (1) and the modified alumina filler are mixed and stirred at 300-400 r / min for 1-2 hours. The mass ratio of the polycarbonate polyol, the water scavenger and the modified alumina filler is (20-30): (40-50): (1-3): (20-30). The modified polycarbonate polyol is first heated to 60-80°C and vacuum dehydrated for 1-2 hours. Subsequently, diphenylmethane diisocyanate is added and reacted at 70-90°C for 2-3 hours. The water scavenger is then added and stirred at 300-400 r / min for 0.5-1 hour. Finally, the modified alumina filler is added and stirred for 1-2 hours to obtain component B. The components A and B are mixed in a mass ratio of (0.8-1.2): 1 to obtain a two-component polyurethane thermal conductive structural adhesive.

7. The method for preparing a two-component polyurethane thermal conductive structural adhesive according to claim 6, characterized in that: In step (3), the preparation process of the potassium perfluorooctane sulfonate solution is as follows: potassium perfluorooctane sulfonate and tetrahydrofuran are mixed in a mass ratio of 1:

10.

8. The method for preparing a two-component polyurethane thermal conductive structural adhesive according to claim 6, characterized in that: In the step (4), the mass ratio of the modified polycarbonate polyol, the modified polyether polyol, the modified alumina filler and the silane coupling agent is preferably 45:35:20:

2.

9. The method for preparing a two-component polyurethane thermal conductive structural adhesive according to claim 6, characterized in that: In the step (4), the mass ratio of diphenylmethane diisocyanate, modified polycarbonate polyol, water scavenger and modified alumina filler is preferably 25:45:2:

25.

10. The method for preparing a two-component polyurethane thermal conductive structural adhesive according to claim 6, characterized in that: The mass ratio of component A to component B is preferably 1:1.

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