High-thermal-conductivity hydrolysis-resistant flame-retardant polyurethane pouring sealant and preparation method thereof

Abstract

The invention discloses a high-thermal-conductivity hydrolysis-resistant flame-retardant polyurethane pouring sealant and a preparation method thereof, and belongs to the technical field of polyurethane adhesives. According to the technical scheme, the paint is prepared by mixing a component A and a component B according to the mass ratio of 100: (15-20), the component A is prepared from 0 to 5 parts of polyether polyol, 10 to 25 parts of modified vegetable oil polyol, 5 to 10 parts of modified hydroxyl-terminated polybutadiene polyol, 0 to 5 parts of a micromolecule chain extender, 60 to 70 parts of modified talcum powder, 3 to 5 parts of a flame retardant, 0.3 to 0.5 part of a coupling agent, 0 to 0.05 part of a catalyst, 0.5 to 2 parts of an anti-hydrolysis agent, 1 to 2 parts of a water absorbent, 0.1 to 0.5 part of a de-foaming agent and 0.05 to 0.1 part of an anti-settling agent; and the component B comprises the following components in parts by weight: 0-10 parts of polyether polyol, 80-97 parts of diisocyanate and 0-10 parts of a viscosity reducer. The pouring sealant disclosed by the invention has the characteristics of high high-temperature hardness, high heat conductivity coefficient, low viscosity and excellent operation performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyurethane adhesives, and particularly relates to a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive and a preparation method thereof. Background Art

[0002] With the rapid development of the new energy vehicle industry and the electrical potting industry, and the continuous upgrading of supporting power batteries, charging piles, conductive busbars, etc., the heat generation of related accessories also increases accordingly. If the heat cannot be conducted in time, it is extremely easy to form local high temperature, which will further cause short circuits in the lines and endanger the safety of personnel and the environment. At the same time, the presence of vibration, external moisture, hot and cold environments, and toxic and harmful substances places higher and higher requirements on the mechanical properties, thermal conductivity, high temperature resistance, weather resistance, and flame retardancy of the potting adhesive. Based on this, it is crucial to develop a high-hardness, high-thermal-conductivity and flame-retardant potting adhesive.

[0003] Potting adhesives are mainly divided into three categories: epoxy, silicone, and polyurethane. Epoxy potting adhesives have poor toughness, are easy to crack, and are not resistant to thermal shock. Silicone potting adhesives have low hardness, low bonding strength, and high costs. Polyurethane potting adhesives have characteristics such as adjustable soft hardness, moderate bonding strength, high elasticity, high impact resistance, high wear resistance, and excellent low-temperature performance. Compared with epoxy and silicone potting adhesives, polyurethane potting adhesives are more suitable for potting in various different fields.

[0004] At present, there are generally some problems in the domestic research on polyurethane thermal-conductivity potting adhesives. For high-thermal-conductivity potting adhesives, there is a problem that the addition amount of thermal-conductivity powder alumina is large, which leads to a large viscosity of the material mixture. A low addition amount of thermal-conductivity powder will lead to low thermal conductivity and poor flame retardancy. Although increasing the particle size of the thermal-conductivity powder and selecting spherical alumina powder can improve the thermal conductivity, there are problems of easy sedimentation and easy wear of the equipment at the same time. Adding nitrides to improve the thermal conductivity also has problems such as large material viscosity and high price. In the prior art, polyurethane potting adhesives generally have problems such as poor high-temperature resistance, long-term high-temperature resistance, and poor hydrolysis resistance. Summary of the Invention

[0005] The present invention provides a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive and a preparation method thereof. The potting adhesive has the characteristics of high hardness at high temperature, high thermal conductivity, and good hydrolysis resistance, and at the same time has low viscosity, low cost, and excellent operability. The present invention also provides a scientific and reasonable preparation method, which is easy for large-scale industrial production.

[0006] The technical solution of the present invention is as follows: In the first aspect, a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is disclosed, which is formed by mixing component A and component B in a mass ratio of 100: (15 - 20); Component A comprises raw materials in the following parts by mass: 0-5 parts of polyether polyol, 10-25 parts of modified vegetable oil polyol, 5-10 parts of modified hydroxyl-terminated polybutadiene polyol, 0-5 parts of small molecule chain extender, 60-70 parts of modified talcum powder, 3-5 parts of flame retardant, 0.3-0.5 parts of coupling agent, 0-0.05 parts of catalyst, 0.5-2 parts of hydrolysis inhibitor, 1-2 parts of water absorbent, 0.1-0.5 parts of defoamer, 0.05-0.1 parts of anti-settling agent; Component B comprises raw materials in the following parts by mass: calculated by mass percentage of Component B, 0-10 parts of polyether polyol, 80-97 parts of diisocyanate, 0-10 parts of viscosity reducer.

[0007] Preferably, the number average molecular weight of the polyether polyol in Component A is 375-400, and the functionality is 2 or 3; the modified vegetable oil polyol is a polyol modified with cashew shell oil, and the functionality is 3.8.

[0008] Preferably, the number average molecular weight of the modified hydroxyl-terminated polybutadiene polyol is 2800, and the functionality is 2.5.

[0009] Preferably, the small molecule chain extender is TMPD, DPG or TMP, the number average molecular weight is 134-150, and the functionality is 2 or 3.

[0010] Preferably, the modified talcum powder is prepared from talcum powder of 200 mesh, 400 mesh and 600 mesh in a ratio of 2:1:0.5.

[0011] Preferably, the flame retardant is isopropyltriphenyl phosphate or diphenoxyphosphine oxide.

[0012] Preferably, the coupling agent is a zinc ricinoleate coupling agent; the catalyst is a delayed environmentally friendly tin catalyst.

[0013] Preferably, the water absorbent is Dibaa 30X; the anti-settling agent is BYK-410; the hydrolysis inhibitor is trimethoxy(3-(glycidylether)propyl)silane.

[0014] Preferably, the polyether polyol in Component B is a polyether polyol synthesized from propylene glycol and propylene oxide, the number average molecular weight is 375-1000, and the functionality is 2-3; the diisocyanate is one of polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate or carbodiimide-uretonimine modified diphenylmethane diisocyanate.

[0015] Second, a preparation method of the high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is disclosed, comprising the following steps: (1) Preparation of Component A: Polyether polyol, modified vegetable oil polyol, modified hydroxyl-terminated polybutadiene polyol, small molecule chain extender, modified talc powder and flame retardant are mixed and dehydrated until the water content is less than 0.05%. Subsequently, the temperature is lowered to 50 - 60 °C, and a coupling agent, a catalyst, an anti-hydrolysis agent, a water absorbent, an antifoaming agent and an anti-settling agent are added in sequence. After thorough grinding and stirring evenly, mechanical bubbles are removed by vacuum and then encapsulated to obtain the potting adhesive Component A; (2) Preparation of Component B: Polyether polyol, diisocyanate and viscosity reducer with a water content controlled below 0.05% are reacted at a temperature of 75 - 85 °C for 2 - 4 h to obtain a prepolymer with an isocyanate group content of 25% - 29%. Mechanical bubbles are removed by vacuum and then encapsulated to obtain the potting adhesive Component B; (3) Components A and B are mixed and stirred evenly at room temperature according to a ratio, and then cured at room temperature for 3 - 7 days to obtain a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In the present invention, modified talc powder with different particle sizes is used to replace the thermal conductive powder, which greatly reduces the production cost. At the same time, it makes the powder easier to infiltrate with polyether polyol, so as to achieve the purpose of increasing the powder addition amount and reducing the system viscosity. The prepared potting adhesive product has a high thermal conductivity and a low viscosity. Its thermal conductivity is above 0.8 W / (m·K), and the mixing viscosity is not higher than 2500 mPa·s (25 °C). This makes its operating performance excellent and easy to pot different structural parts. Moreover, the process of the present invention is simple and easy for large-scale industrial production.

[0017] 2. Through the selection of vegetable oil-modified polyol and hydroxyl-terminated polybutadiene raw materials and formula optimization, and the selection and matching of raw materials with different functionalities, the hydrophobicity of the product is improved. Through the design of crosslinking density and the addition of silane-based anti-hydrolysis agents, the water resistance and high temperature resistance at 150 °C of the colloid are further improved.

[0018] Through three anti-hydrolysis barriers, they work together: ① Vegetable oil polyol is incompatible with water due to the presence of its oil-like substances, which will first prevent the entry of water molecules; ② Due to the presence of ester bonds, the carboxyl groups generated after hydrolysis gradually enter the system and react with the epoxy groups of the silane-based anti-hydrolysis agent to generate hydroxyl groups, thus inhibiting the catalytic effect of carboxyl groups on hydrolysis. At the same time, the further reaction between hydroxyl groups and epoxy groups reconnects the broken bonds caused by hydrolysis, resulting in better hydrolysis stability; ③ Further, due to the presence of the weakly polar substance of hydroxyl-terminated polybutadiene, which is completely incompatible with water, the destructive effect of water molecules is greatly weakened. The three work together to make the prepared potting adhesive have excellent hydrolysis resistance.

[0019] 3. In the present invention, the zinc ricinoleate substance not only functions as a coupling agent, but also the metal zinc can act as a catalyst, reducing the amount of catalyst used. Additionally, the zinc ricinoleate substance has better compatibility with the system, and the zinc ions can enhance the binding ability with the polar surface, resulting in better bonding effect of the potting adhesive. Detailed implementation manners

[0020] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments.

[0021] All raw materials used in the embodiments are commercially available unless otherwise specified.

[0022] The indexes of some raw materials used in the embodiments are as follows: PPG400: number average molecular weight 400, functionality 2, hydroxyl value: 280 ± 15 mgKOH / g, polyoxypropylene glycol; PPG125: number average molecular weight 375, functionality 3, hydroxyl value: 450 ± 15 mgKOH / g, polyether polyol synthesized from propylene glycol and propylene oxide; PPG1000: number average molecular weight 1000, functionality 2, hydroxyl value: 112 ± 15 mgKOH / g, polyoxypropylene glycol; MN500: number average molecular weight 500, functionality 3, hydroxyl value: 340 ± 10 mgKOH / g, polyether polyol synthesized from propylene glycol and propylene oxide; TMP: number average molecular weight 135, functionality 3, trimethylolpropane; DPG: number average molecular weight 134, functionality 2, dipropylene glycol; TMPD: number average molecular weight 146, functionality 2, 2,2,3 - trimethyl - 1,3 - pentanediol; YGK - 9001: hydroxyl value 175 mgKOH / g, functionality 3.8; modified cashew shell oil polyol; HTPB: hydroxyl - terminated polybutadiene polyol, number average molecular weight 2800, functionality 2.5; MDI - 50: diphenylmethane diisocyanate; PM200: polymethylene polyphenyl isocyanate; TXIB: 2,2,4 - trimethyl - 1,3 - pentanediol diisobutyrate; 103C: carbodiimide - uretonimine modified diphenylmethane diisocyanate; T - 120: delayed environmentally friendly tin - based catalyst; Defoamer: BYK - 066; Liquid anti - settling agent: BYK - 410; Water absorbent: Dibaa 30X; Flame retardants: isopropyltriphenyl phosphate (IPPP50), diphenoxyphosphine oxide (DOPO); Hydrolysis inhibitor: trimethoxy(3-(glycidoxy)propyl)silane; Coupling agent: zinc ricinoleate type AKT-632; Modified talc powder HS-335: prepared by the following steps: a. Dissolve zinc ricinoleate as a surface treatment agent in isopropanol according to a mass ratio of 1:8 to obtain a mixed solution. Add talc powder according to a mass ratio of 3:1 of talc powder to the mixed solution. Stir with a high-speed mixer at 2000 r / min for 90 min, then use a vacuum pump for filtration, and wash with ethyl acetate to remove the excess surface treatment agent to obtain wet modified talc powder; b. Dry the wet modified talc powder at 120 °C for 5 h, crush the lumps with a pulverizer, and sieve to obtain the original modified talc powder. The maximum particle size of the obtained original modified talc powder is 100 μm; c. Classify the original modified talc powder into 200 mesh, 400 mesh, and 600 mesh according to the mesh number and prepare the required modified talc powder HS-335 according to a ratio of 2:1:0.5.

[0023] Example 1 The preparation method of the high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive includes the following steps: (1) Preparation of component A: By mass, mix 10 parts of YGK-9001 (modified vegetable oil polyol), 10 parts of HTPB (modified hydroxyl-terminated polybutadiene polyol), 2.6 parts of TMP (small molecule chain extender), 70 parts of modified talc powder HS-335, and 3 parts of IPPP50 (flame retardant). Dehydrate at 105 °C under a vacuum of less than -0.095 MPa until the water content is less than 0.05%. Then cool down to 50 °C and sequentially add 0.5 part of AKT-632 (coupling agent), 0.03 part of T-120 (catalyst), 2 parts of trimethoxy(3-(glycidoxy)propyl)silane (hydrolysis inhibitor), 1.3 parts of Dibaa 30X (water absorbent), 0.07 part of BYK-410 (anti-settling agent), and 0.5 part of BYK-066 (defoaming agent). Grind and stir evenly with a high-speed disperser at 2500 r / min, evacuate to remove mechanical bubbles and then encapsulate to obtain potting adhesive component A; (2) Preparation of component B: By mass, mix 3 parts of PPG125 (polyether polyol) and 97 parts of PM200 (diisocyanate), react at 80 °C for 3 h to obtain a prepolymer with an isocyanate group content of 28%, evacuate to remove mechanical bubbles and then encapsulate to obtain potting adhesive component B; (3) Mix components A and B at room temperature in a mass ratio of 100:15 and stir evenly. After aging at room temperature for 5 days, a highly thermally conductive, hydrolysis-resistant, and flame-retardant polyurethane potting adhesive is obtained.

[0024] Example 2 The preparation method of the highly thermally conductive, hydrolysis-resistant, and flame-retardant polyurethane potting adhesive includes the following steps: (1) Preparation of component A: By mass, mix 15.3 parts of YGK-9001 (modified vegetable oil polyol), 5 parts of TMPD (small molecule chain extender), 5 parts of HTPB (modified hydroxyl-terminated polybutadiene polyol), 1.2 parts of PPG125 (polyether polyol), 67 parts of modified talc powder HS-335, and 4.3 parts of DOPO (flame retardant). Dehydrate at 105°C under a vacuum of less than -0.095 MPa until the water content is less than 0.05%. Then cool down to 60°C and sequentially add 0.3 parts of AKT-632 (coupling agent), 0.01 parts of T-120 (catalyst), 0.5 parts of trimethoxy(3-(glycidylethoxy)propyl)silane (hydrolysis inhibitor), 1 part of Dibaa 30X (water absorbent), 0.1 part of BYK-410 (anti-settling agent), and 0.3 parts of BYK-066 (defoaming agent). Stir and grind evenly with a high-speed disperser at 2500 r / min, and then evacuate to remove mechanical bubbles and encapsulate to obtain component A of the potting adhesive; (2) Component B: By mass, mix 2.9 parts of PPG1000 (polyether polyol), 22.5 parts of MDI-50 (diisocyanate), 71.6 parts of PM200 (diisocyanate), and 3 parts of viscosity reducer TXIB. React at 75°C for 4 h to obtain a prepolymer with an isocyanate group content of 29%. Evacuate to remove mechanical bubbles and then encapsulate to obtain component B of the potting adhesive; (3) Mix components A and B at room temperature in a mass ratio of 100:20 and stir evenly. After aging at room temperature for 3 days, a highly thermally conductive, hydrolysis-resistant, and flame-retardant polyurethane potting adhesive is obtained.

[0025] Example 3 The preparation method of the highly thermally conductive, hydrolysis-resistant, and flame-retardant polyurethane potting adhesive includes the following steps: (1) Preparation of Component A: By mass fraction, 25 parts of YGK-9001 (modified vegetable oil polyol), 5 parts of HTPB (modified hydroxyl-terminated polybutadiene polyol), 1.3 parts of DPG (small molecule chain extender), 60 parts of modified talc powder HS-335 and 5 parts of IPPP50 (flame retardant) are mixed. Dehydration is carried out at 110 °C under a vacuum of less than -0.095 MPa until the water content is less than 0.05%. Subsequently, the temperature is lowered to 55 °C, and 0.5 part of AKT-632 (coupling agent), 1 part of trimethoxy(3-(glycidylether)propyl)silane (hydrolysis inhibitor), 2 parts of Dibaa 30X (water absorbent), 0.1 part of BYK-410 (anti-settling agent) and 0.1 part of BYK-066 (defoaming agent) are added in sequence. The mixture is thoroughly ground and stirred evenly by a high-speed disperser at 2500 r / min. After removing mechanical bubbles by vacuum pumping, Component A of the potting adhesive is obtained by encapsulation; (2) Preparation of Component B: By mass fraction, 3 parts of MN500 (polyether polyol), 29 parts of MDI-50 (diisocyanate) and 68 parts of 103C (diisocyanate) are mixed and reacted at 85 °C for 2 h to obtain a prepolymer with an isocyanate group content of 28.5%. After removing mechanical bubbles by vacuum pumping, Component B of the potting adhesive is obtained by encapsulation; (3) Components A and B are mixed and stirred evenly at room temperature according to a mass ratio of 100:16. After curing at room temperature for 7 days, a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

[0026] Example 4 The preparation method of the high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive includes the following steps: (1) Preparation of Component A: By mass fraction, 20 parts of YGK-9001 (modified vegetable oil polyol), 5 parts of PPG400 (polyether polyol), 7 parts of HTPB (modified hydroxyl-terminated polybutadiene polyol), 60 parts of modified talc powder HS-335 and 5 parts of IPPP50 (flame retardant) are mixed. Dehydration is carried out at 110 °C under a vacuum of less than -0.095 MPa until the water content is less than 0.05%. Subsequently, the temperature is lowered to 55 °C, and 0.4 part of AKT-632 (coupling agent), 0.05 part of T-120 (catalyst), 1 part of trimethoxy(3-(glycidylether)propyl)silane (hydrolysis inhibitor), 1 part of Dibaa 30X (water absorbent), 0.05 part of BYK-410 (anti-settling agent) and 0.5 part of BYK-066 (defoaming agent) are added in sequence. The mixture is thoroughly ground and stirred evenly by a high-speed disperser at 2500 r / min. After removing mechanical bubbles by vacuum pumping, Component A of the potting adhesive is obtained by encapsulation; (2)Preparation of Component B: 10 parts of PPG1000 (polyether polyol), 64 parts of MDI-50 (diisocyanate), 16 parts of PM200 (diisocyanate), and 10 parts of viscosity reducer TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate) were mixed evenly and reacted at 80 °C for 4 h to obtain a prepolymer with an isocyanate group content of 25%. After vacuum degassing to remove mechanical bubbles, it was encapsulated to obtain Component B of the potting adhesive; (3)Components A and B were mixed and stirred evenly at room temperature in a mass ratio of 100:16. After curing at room temperature for 4 days, a low-density and high-thermal-conductivity polyurethane potting adhesive was obtained.

[0027] Comparative Example 1 Different from Example 1, in this comparative example, the "modified vegetable oil polyol" was replaced with an equal amount of "polyether polyol in Component A", and the remaining preparation methods and steps were the same as those in Example 1.

[0028] Comparative Example 2 Different from Example 1, in this comparative example, the "modified hydroxyl-terminated polybutadiene polyol" was replaced with an equal amount of "modified vegetable oil polyol", and the remaining preparation methods and steps were the same as those in Example 1.

[0029] Comparative Example 3 Different from Example 1, in this comparative example, no hydrolysis inhibitor was added, and the remaining preparation methods and steps were the same as those in Example 1.

[0030] Comparative Example 4 Different from Example 1, in this comparative example, the "zinc ricinoleate" was replaced with an equal amount of "commercially available conventional coupling agent KH560", and the remaining preparation methods and steps were the same as those in Example 1.

[0031] Comparative Example 5 Different from Example 1, in this comparative example, the "modified talc powder" was replaced with an equal amount of "thermal conductive powder purchased from Shandong Aluminum Industry Co., Ltd., Al(OH) 3 powder, model H-W-95", and the remaining preparation methods and steps were the same as those in Example 1.

[0032] Comparative Example 6 Different from Example 1, in this comparative example, the "modified talc powder" was replaced with an equal amount of "200-mesh talc powder", and the remaining preparation methods and steps were the same as those in Example 1.

[0033] Performance Test The products of the examples and comparative examples were subjected to performance detection according to the following standards, and the obtained performance test results are shown in Table 1: Viscosity: "Determination of Viscosity of Adhesives - GB / T2794-2013"; Hardness: "GB / T531.1-2008 Test Method for Indentation Hardness of Vulcanized Rubber or Thermoplastic Rubber"; Thermal Conductivity: "ASTM D5470 Standard Test Method for Thermal Conductivity of Thermal Insulation Materials"; Tensile Strength: "GB / T528-2009 Determination of Tensile Stress-Strain Properties of Vulcanized Rubber or Thermoplastic Rubber"; Water Absorption: "ISO 20393:2007 Thermal Insulation Materials - Determination of Long-Term Water Absorption by the Diffusion Method"; Flame Retardancy (UL-94): "ANSI / UL94 Flammability Tests for Plastic Materials for Parts in Devices and Appliances"; The 150°C high-temperature resistance test is specifically as follows: Observe the surface crack situation after placing it in an oven at 150°C for 72h.

[0034] Table 1 Performance Test Table of Examples and Comparative Examples

[0035] It can be seen from the data in the table that in Comparative Examples 1-3, ordinary polyether was used to replace vegetable oil polyol, modified vegetable oil was used to replace terminal hydroxyl polybutadiene ether in the system, and the anti-hydrolytic agent was not added. The triple anti-hydrolytic barriers were respectively damaged in different ways, and the entry of water molecules led to a significant increase in the water absorption rate of the system in 60 days. At the same time, the decrease in the performance retention rate after 1500h of testing at 85°C / 85% humidity also confirmed this point.

[0036] In Comparative Example 4, zinc ricinoleate was replaced with a conventional coupling agent, lacking the catalytic effect, resulting in a significantly lower strength increase rate of the system, and then resulting in a lower hardness of only 80D after curing at room temperature for 5 days. Moreover, the conventional coupling agent KH560 has a general compatibility with the system in terms of structure. Zinc ricinoleate-based coupling agents have a "similar solubility" with vegetable oil polyol due to their structure, making the powder dispersion in the system more uniform, and the thermal conduction network formed by it is better, having a higher thermal conductivity.

[0037] When comparing Example 1 with Comparative Example 5, replacing an equal amount of "commercially available thermal conductive powder" with "modified talc powder", good thermal conductivity can still be achieved on the premise of significantly reducing the cost. This is mainly because the pretreatment of talc powder and the combination of different particle sizes form a relatively smooth thermal conduction path, and it has a better thermal conductivity compared with conventional untreated thermal conductive powder. In addition, the commercially available thermal conductive powder is prone to sedimentation problems due to lack of surface treatment, and thus is prone to cracking problems during the 150°C high-temperature resistance test.

[0038] In Comparative Example 6, ordinary talc powder was used, and the viscosity of the system was greatly reduced, but there were also sedimentation problems, resulting in poor uniformity of the prepared product, and cracking problems caused by local non-uniformity during the 150°C high-temperature resistance test.

Claims

1. High thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting glue, characterized in that: It is made by mixing component A and component B in a mass ratio of 100:(15~20); Component A includes the following raw materials in parts by weight: 0-5 parts of polyether polyol, 10-25 parts of modified vegetable oil polyol, 5-10 parts of modified hydroxyl-terminated polybutadiene polyol, 0-5 parts of small molecule chain extender, 60-70 parts of modified talc, 3-5 parts of flame retardant, 0.3-0.5 parts of coupling agent, 0-0.05 parts of catalyst, 0.5-2 parts of anti-hydrolysis agent, 1-2 parts of water absorbent, 0.1-0.5 parts of defoaming agent, and 0.05-0.1 parts of anti-settling agent; Component B includes the following raw materials in parts by mass: 0-10 parts of polyether polyol, 80-97 parts of diisocyanate, and 0-10 parts of viscosity reducer, calculated as a percentage of the mass of component B.

2. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The number average molecular weight of the polyether polyol in component A is 375-400, and the functionality is 2 or 3; the modified vegetable oil polyol is a polyol modified with cashew nut shell oil, and the functionality is 3.

8.

3. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The number average molecular weight of the modified hydroxyl-terminated polybutadiene polyol is 2800 and the functionality is 2.

5.

4. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The small molecule chain extender is TMPD, DPG or TMP, with a number average molecular weight of 134-150 and a functionality of 2 or 3.

5. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The modified talc powder is prepared by mixing 200 mesh, 400 mesh and 600 mesh talc powder in a ratio of 2:1:0.

5.

6. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The flame retardant is isopropylated triphenyl phosphate or diphenoxy phosphorus oxide.

7. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The coupling agent is a zinc ricinoleate coupling agent; the catalyst is a delayed environmentally friendly tin catalyst.

8. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The water absorbent is Dibaa30X; the anti-settling agent is BYK-410; and the anti-hydrolysis agent is trimethoxy (3-(glycidyl ether) propyl) silane.

9. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to claim 1, characterized in that: The polyether polyol in component B is a polyether polyol synthesized from propylene glycol and propylene oxide, with a number average molecular weight of 375-1000 and a functionality of 2-3; the diisocyanate is one of polymethylene polyphenyl isocyanate, diphenylmethane diisocyanate or carbodiimide-uretonimine modified diphenylmethane diisocyanate.

10. A method for preparing the highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Preparation of component A: polyether polyol, modified vegetable oil polyol, modified hydroxyl-terminated polybutadiene polyol, small molecule chain extender, modified talc and flame retardant are mixed, dehydrated to a moisture content of less than 0.05%, then cooled to 50-60°C, coupling agent, catalyst, anti-hydrolysis agent, water absorbent, defoaming agent and anti-settling agent are added in sequence, fully ground and stirred, vacuumed to remove mechanical bubbles and then packaged to obtain potting glue component A; (2) Preparation of component B: The polyether polyol, diisocyanate and viscosity reducer with a moisture content of less than 0.05% are reacted at a temperature of 75-85°C for 2-4 hours to obtain a prepolymer with an isocyanate content of 25%-29%. The prepolymer is vacuumed to remove mechanical bubbles and then packaged to obtain component B of the potting glue; (3) Mix components A and B in proportion and stir them evenly at room temperature. After aging at room temperature for 3 to 7 days, a highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

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