High thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive and preparation method thereof

Abstract

The present invention discloses a high-thermal-conductivity, hydrolysis-resistant, and flame-retardant polyurethane potting adhesive and its preparation method, belonging to the technical field of polyurethane adhesives. The technical solution is as follows: Component A and Component B are mixed in a mass ratio of 100:(15-20); Component A includes 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 a small molecule chain extender, 60-70 parts of modified talc, 3-5 parts of a flame retardant, 0.3-0.5 parts of a coupling agent, 0-0.05 parts of a catalyst, 0.5-2 parts of an anti-hydrolysis agent, 1-2 parts of a water absorbent, 0.1-0.5 parts of a defoaming agent, and 0.05-0.1 parts of an anti-settling agent; Component B includes 0-10 parts of a polyether polyol, 80-97 parts of a diisocyanate, and 0-10 parts of a viscosity reducer. The potting glue of the present invention has the characteristics of high hardness at high temperature and high thermal conductivity, low viscosity and excellent operating performance.

Description

Technical Field

[0001] The 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 and electrical potting industries, and the continuous upgrading of supporting power batteries, charging stations, and conductive busbars, the heat generated by these components is also increasing. If heat cannot be transferred in a timely manner, it can easily lead to localized high temperatures, causing short circuits and endangering personnel and environmental safety. At the same time, the presence of vibration, external moisture, cold and hot environments, and toxic and hazardous substances are placing increasingly stringent demands on the potting compound's mechanical properties, thermal conductivity, high temperature resistance, weather resistance, and flame retardancy. Therefore, the development of a high-hardness, high-thermal-conductivity, and flame-retardant potting compound is crucial.

[0003] Potting compounds are primarily categorized into three main types: epoxy, silicone, and polyurethane. Epoxy potting compounds suffer from poor toughness, cracking, and poor thermal shock resistance. Silicone potting compounds suffer from low hardness, low bond strength, and high cost. Polyurethane potting compounds, on the other hand, offer adjustable hardness, moderate bond strength, high elasticity, high impact and wear resistance, and excellent low-temperature resistance. Compared to epoxy and silicone potting compounds, polyurethane potting compounds are more suitable for potting in a variety of applications.

[0004] Currently, there are some common problems in the research of polyurethane thermal conductive potting compounds in China. High thermal conductivity potting compounds suffer from the problem of large amounts of thermal conductive powder alumina added, which leads to high material viscosity. Low thermal conductivity powder additions lead to low thermal conductivity and poor flame retardancy. Increasing the particle size of thermal conductive powder and selecting spherical alumina powder can improve thermal conductivity, but they also cause problems such as sedimentation and equipment wear. Adding nitrides to increase thermal conductivity also leads to high material viscosity and high prices. Existing polyurethane potting compounds generally suffer from poor high temperature resistance, long-term high temperature resistance, and poor hydrolysis resistance. Summary of the Invention

[0005] The present invention provides a highly thermally conductive, hydrolysis-resistant, flame-retardant polyurethane potting compound and a preparation method thereof. The potting compound exhibits high high-temperature hardness, high thermal conductivity, and good hydrolysis resistance, while also exhibiting low viscosity, low cost, and excellent operability. The present invention also provides a scientific and rational preparation method, making it amenable to large-scale industrial production.

[0006] The technical solution of the present invention is:

[0007] In the first aspect, a highly thermally conductive, hydrolysis-resistant, and flame-retardant polyurethane potting compound is disclosed, which is prepared by mixing component A and component B in a mass ratio of 100:(15-20);

[0008] Component A includes the following raw materials in 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 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;

[0009] 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.

[0010] 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 cashew nut shell liquid modified polyol, and the functionality is 3.8.

[0011] Preferably, the number average molecular weight of the modified hydroxyl-terminated polybutadiene polyol is 2800 and the functionality is 2.5.

[0012] Preferably, 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.

[0013] Preferably, 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.

[0014] Preferably, the flame retardant is isopropylated triphenyl phosphate or diphenoxyphosphorus oxide.

[0015] Preferably, the coupling agent is a zinc ricinoleate coupling agent; and the catalyst is a delayed environmentally friendly tin catalyst.

[0016] Preferably, the water absorbent is Dibaa 30X; the anti-settling agent is BYK-410; and the anti-hydrolysis agent is trimethoxy(3-(glycidylether)propyl)silane.

[0017] Preferably, 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.

[0018] In a second aspect, a method for preparing the highly thermally conductive, hydrolysis-resistant, flame-retardant polyurethane potting compound is disclosed, comprising the following steps:

[0019] (1) Preparation of component A: After mixing polyether polyol, modified vegetable oil polyol, modified hydroxyl-terminated polybutadiene polyol, small molecule chain extender, modified talc and flame retardant, dehydrate to a moisture content of less than 0.05%, then cool to 50-60°C, add coupling agent, catalyst, anti-hydrolysis agent, water absorbent, defoaming agent and anti-settling agent in sequence, grind and stir thoroughly, vacuum to remove mechanical bubbles and then encapsulate to obtain component A of the potting compound;

[0020] Preparation of component B: Polyether polyol, diisocyanate, and viscosity reducer with a moisture content of less than 0.05% are reacted at 75-85°C for 2-4 hours to obtain a prepolymer with an isocyanate content of 25-29%. The prepolymer is then vacuumed to remove mechanical bubbles and packaged to obtain component B of the potting compound.

[0021] (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 high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention replaces thermal conductive powder with modified talc powder of different particle sizes, which greatly reduces production costs and makes the powder easier to be infiltrated with polyether polyol, thereby achieving the purpose of increasing the amount of powder added and reducing the viscosity of the system. The prepared potting glue product has high thermal conductivity and low viscosity, its thermal conductivity is above 0.8W / (m·K), and the mixed viscosity is not higher than 2500mPa·s (25°C), which makes it have excellent operating performance and easy to pot different structural parts. In addition, the process of the present invention is simple and easy to large-scale industrial production.

[0024] 2. The present invention improves the hydrophobicity of the product by selecting and optimizing the raw materials of vegetable oil-modified polyol and terminal hydroxyl polybutadiene, and selecting raw materials with different functionalities. The water resistance and high temperature resistance of the colloid at 150°C are further improved by designing the cross-linking density and adding a silane anti-hydrolysis agent.

[0025] Through the triple anti-hydrolysis barrier, they work together: ① Vegetable oil polyols are incompatible with water due to the presence of oily 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 silane anti-hydrolysis agents to generate hydroxyl groups, thereby inhibiting the catalytic effect of the carboxyl groups on hydrolysis. At the same time, the hydroxyl groups further react with the epoxy groups to reconnect the broken bonds caused by hydrolysis, and the hydrolysis stability is better; ③ Furthermore, the presence of the weak polar substance of terminal hydroxyl polybutadiene is completely incompatible with water, which greatly reduces the destructiveness of water molecules. The three work together to make the prepared potting compound have excellent hydrolysis resistance.

[0026] 3. The zinc ricinoleate used in the present invention not only acts as a coupling agent, but also has the function of a catalyst, thereby reducing the amount of catalyst used. In addition, the zinc ricinoleate has excellent compatibility with the system, and the zinc ions can enhance the binding ability with polar surfaces, thereby improving the bonding effect of the potting adhesive. DETAILED DESCRIPTION

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0028] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0029] Some of the raw material indicators used in the examples are as follows:

[0030] PPG400: number average molecular weight 400, functionality 2, hydroxyl value: 280±15mgKOH / g, polyoxypropylene glycol;

[0031] PPG125: number average molecular weight 375, functionality 3, hydroxyl value: 450±15mgKOH / g, polyether polyol synthesized from propylene glycol and propylene oxide;

[0032] PPG1000: number average molecular weight 1000, functionality 2, hydroxyl value: 112±15mgKOH / g, polyoxypropylene glycol;

[0033] MN500: number average molecular weight 500, functionality 3, hydroxyl value: 340±10mgKOH / g, polyether polyol synthesized from propylene glycol and propylene oxide;

[0034] TMP: number average molecular weight 135, functionality 3, trimethylolpropane;

[0035] DPG: number average molecular weight 134, functionality 2, dipropylene glycol;

[0036] TMPD: number average molecular weight 146, functionality 2,2,2,3-trimethyl-1,3-pentanediol;

[0037] YGK-9001: hydroxyl value 175 mgKOH / g, functionality 3.8; modified cashew nut shell liquid polyol;

[0038] HTPB: hydroxy-terminated polybutadiene polyol, number average molecular weight 2800, functionality 2.5;

[0039] MDI-50: diphenylmethane diisocyanate;

[0040] PM200: polymethylene polyphenyl isocyanate;

[0041] TXIB: 2,2,4-trimethylpentanediol diisobutyrate;

[0042] 103C: carbodiimide-uretonimine modified diphenylmethane diisocyanate;

[0043] T-120: Delayed environmentally friendly tin catalyst;

[0044] Defoamer: BYK-066;

[0045] Liquid anti-settling agent: BYK-410;

[0046] Water absorbent: Dibaa 30X;

[0047] Flame retardants: isopropylated triphenyl phosphate (IPPP50), diphenoxyphosphorus oxide (DOPO);

[0048] Anti-hydrolysis agent: trimethoxy (3-(glycidyl ether) propyl) silane;

[0049] Coupling agent: zinc ricinoleate AKT-632;

[0050] Modified talc HS-335: prepared by the following steps:

[0051] a. Dissolve the surface treatment agent zinc ricinoleate in isopropyl alcohol at a mass ratio of 1:8 to obtain a mixed solution; add talcum powder at a mass ratio of talcum powder to the mixed solution of 3:1; stir the mixture at 2000 rpm for 90 min with a high-speed stirrer; then filter the mixture with a vacuum pump and wash with ethyl acetate to remove excess surface treatment agent to obtain a modified talcum powder wet material;

[0052] b. Drying the modified talc wet material at 120° C. for 5 h, crushing the lumps with a grinder, and sieving to obtain a modified talc raw material. The maximum particle size of the obtained modified talc raw material is 100 μm;

[0053] c. The modified talc raw material is divided into 200 mesh, 400 mesh, and 600 mesh according to the mesh size and prepared in a ratio of 2:1:0.5 to obtain the required modified talc HS-335.

[0054] Example 1

[0055] The method for preparing the highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive comprises the following steps:

[0056] (1) Preparation of component A: 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 HS-335 and 3 parts of IPPP50 (flame retardant) were mixed by weight, and dehydrated at 105 ° C and vacuum degree below -0.095 MPa to less than 0.05% of moisture, then cooled to 50 ° C, and 0.5 parts of AKT-632 (coupling agent), 0.03 parts of T-120 (catalyst), 2 parts of trimethoxy (3- (glycidyl ether) propyl) silane (anti-hydrolysis agent), 1.3 parts of Dibaa 30X (water absorbent), 0.07 parts BYK-410 (anti-settling agent) and 0.5 parts BYK-066 (defoaming agent) were fully ground and stirred at 2500 r / min in a high-speed disperser. After vacuuming to remove mechanical bubbles, the mixture was packaged to obtain component A of the potting compound.

[0057] (2) Preparation of component B: 3 parts by mass of PPG125 (polyether polyol) and 97 parts by mass of PM200 (diisocyanate) were mixed and reacted at 80°C for 3 h to obtain a prepolymer with an isocyanate content of 28%. The mixture was vacuumed to remove mechanical bubbles and then packaged to obtain component B of the potting compound.

[0058] (3) Components A and B are mixed and stirred evenly at a mass ratio of 100:15 at room temperature. After aging at room temperature for 5 days, a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

[0059] Example 2

[0060] The method for preparing the highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive comprises the following steps:

[0061] (1) Preparation of component A: 15.3 parts of YGK-9001 (modified vegetable oil polyol), 5 parts of TMPD (small molecule chain extender), 5 parts of HTPB (modified terminal hydroxyl polybutadiene polyol), 1.2 parts of PPG125 (polyether polyol), 67 parts of modified talc HS-335 and 4.3 parts of DOPO (flame retardant) were mixed, and dehydrated at 105 ° C and vacuum degree below -0.095 MPa to less than 0.05% of moisture, then cooled to 60 ° C, and 0.3 parts of AKT-632 (coupling agent), 0.01 parts of T-120 (catalyst), 0.5 parts of trimethoxy (3- (glycidyl ether) propyl) silane (anti-hydrolysis agent), 1 part of Dibaa 30X (water absorbent), 0.1 part BYK-410 (anti-settling agent) and 0.3 part BYK-066 (defoaming agent) were fully ground and stirred at 2500 r / min in a high-speed disperser. After vacuuming to remove mechanical bubbles, the mixture was packaged to obtain the potting compound component A.

[0062] (2) Component B: 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 were mixed by weight and reacted at 75°C for 4 hours to obtain a prepolymer with an isocyanate content of 29%. The mixture was vacuumed to remove mechanical bubbles and then packaged to obtain component B of the potting compound.

[0063] (3) Components A and B are mixed and stirred evenly at a mass ratio of 100:20 at room temperature. After aging at room temperature for 3 days, a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

[0064] Example 3

[0065] The method for preparing the highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive comprises the following steps:

[0066] (1) Preparation of component A: 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 HS-335 and 5 parts of IPPP50 (flame retardant) were mixed by weight, and dehydrated at 110 ° C and vacuum degree below -0.095 MPa to a moisture content of less than 0.05%. Then, the temperature was lowered to 55 ° C, and 0.5 parts of AKT-632 (coupling agent), 1 part of trimethoxy (3- (glycidyl ether) propyl) silane (anti-hydrolysis agent), 2 parts of Dibaa 30X (water absorbent), 0.1 parts of BYK-410 (anti-settling agent) and 0.1 parts of BYK-066 (defoaming agent) were added in sequence. The mixture was fully ground and stirred at 2500 r / min in a high-speed disperser. After vacuum removal of mechanical bubbles, the mixture was encapsulated to obtain component A of the potting compound.

[0067] (2) Preparation of component B: 3 parts by mass of MN500 (polyether polyol), 29 parts of MDI-50 (diisocyanate) and 68 parts of 103C (diisocyanate) were mixed and reacted at 85°C for 2 h to obtain a prepolymer with an isocyanate content of 28.5%. The mixture was vacuumed to remove mechanical bubbles and then packaged to obtain component B of the potting compound.

[0068] (3) Components A and B are mixed and stirred evenly at a mass ratio of 100:16 at room temperature. After aging at room temperature for 7 days, a high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

[0069] Example 4

[0070] The method for preparing the highly thermally conductive, hydrolysis-resistant and flame-retardant polyurethane potting adhesive comprises the following steps:

[0071] (1) Preparation of component A: 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 HS-335 and 5 parts of IPPP50 (flame retardant) were mixed by weight, and dehydrated at 110 ° C and vacuum degree below -0.095 MPa to less than 0.05% of moisture, then cooled to 55 ° C, and 0.4 parts of AKT-632 (coupling agent), 0.05 parts of T-120 (catalyst), 1 part of trimethoxy (3- (glycidyl ether) propyl) silane (anti-hydrolysis agent), 1 part of Dibaa 30X (water absorbent), 0.05 parts BYK-410 (anti-settling agent) and 0.5 parts BYK-066 (defoaming agent) were fully ground and stirred at 2500 r / min in a high-speed disperser. After vacuuming to remove mechanical bubbles, the mixture was packaged to obtain potting compound component A.

[0072] (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 hours to obtain a prepolymer with an isocyanate content of 25%. The mixture was vacuumed to remove mechanical bubbles and then packaged to obtain component B of the potting compound.

[0073] (3) Components A and B are mixed and stirred evenly at a mass ratio of 100:16 at room temperature. After aging at room temperature for 4 days, a low-density, high-thermal-conductivity polyurethane potting adhesive is obtained.

[0074] Comparative Example 1

[0075] The difference from Example 1 is that the "modified vegetable oil polyol" in this comparative example is replaced by an equal amount of "polyether polyol in component A", and the rest of the preparation methods and steps are the same as those in Example 1.

[0076] Comparative Example 2

[0077] The difference from Example 1 is that the "modified terminal hydroxyl polybutadiene polyol" in this comparative example is replaced by an equal amount of "modified vegetable oil polyol", and the remaining preparation methods and steps are the same as those in Example 1.

[0078] Comparative Example 3

[0079] The difference from Example 1 is that no anti-hydrolysis agent is added in this comparative example, and the remaining preparation methods and steps are the same as those in Example 1.

[0080] Comparative Example 4

[0081] The difference from Example 1 is that in this comparative example, "zinc ricinoleate" is replaced by an equal amount of "commercially available conventional coupling agent KH560", and the remaining preparation methods and steps are the same as those in Example 1.

[0082] Comparative Example 5

[0083] The difference from Example 1 is that the "modified talc powder" in this comparative example is replaced by an equal amount of "commercially available thermal conductive powder purchased from Shandong Aluminum Co., Ltd. Al(OH)3 powder, model HW-95", and the rest of the preparation methods and steps are the same as in Example 1.

[0084] Comparative Example 6

[0085] The difference from Example 1 is that the "modified talc powder" in this comparative example is replaced by an equal amount of "200-mesh talc powder", and the remaining preparation methods and steps are the same as those in Example 1.

[0086] Performance Testing

[0087] The performance of the products of the embodiment and the comparative example was tested according to the following standards. The obtained performance test results are shown in Table 1:

[0088] Viscosity: GB / T2794-2013 Determination of viscosity of adhesives;

[0089] Hardness: GB / T531.1-2008 Test method for indentation hardness of vulcanized rubber or thermoplastic rubber;

[0090] Thermal conductivity: ASTM D5470 Standard Test Method for Thermal Conductivity of Thermally Conductive Insulating Materials;

[0091] Tensile strength: GB / T528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber;

[0092] Water absorption: ISO 20393:2007 Thermal insulation materials - Diffusion method - Long-term water absorption;

[0093] Flame retardant (UL-94): "ANSI / UL94 Flammability Tests for Plastic Materials for Equipment and Appliance Components";

[0094] The 150℃ high temperature resistance test is as follows: place the product in a 150℃ oven for 72 hours and then observe the surface cracks.

[0095] Table 1 Performance test table of embodiments and comparative examples

[0096]

[0097] As can be seen from the data in the table, Comparative Examples 1-3 respectively use ordinary polyether instead of vegetable oil polyol, modify vegetable oil instead of terminal hydroxyl polybutadiene ether in the system, and do not add anti-hydrolysis agent, which destroys the triple barrier against hydrolysis in different ways. The entry of water molecules causes a significant increase in the water absorption rate of the system after 60 days. At the same time, the decrease in performance retention rate after 1500 hours of 85℃ / 85% humidity testing also confirms this point.

[0098] In Comparative Example 4, zinc ricinoleate was replaced with a conventional coupling agent, which lacked catalytic activity, resulting in a significantly lower strength and speed in the system. This in turn led to a low hardness of only 80D after aging at room temperature for 5 days. Furthermore, the conventional coupling agent KH560 had general structural compatibility with the system. Zinc ricinoleate coupling agents, due to their structure, exhibit "similar dissolvability" with vegetable oil polyols, making the powder more evenly dispersed in the system. The resulting thermal network was superior, resulting in a higher thermal conductivity coefficient.

[0099] Compared to Comparative Example 5, Example 1 replaces the modified talc with an equal amount of commercially available thermally conductive powder. While significantly reducing costs, it still achieves excellent thermal conductivity. This is primarily due to the talc's pretreatment and the combination of different particle sizes, which creates a smoother thermal conductivity path and exhibits superior thermal conductivity compared to conventional untreated thermally conductive powder. Furthermore, commercially available thermally conductive powders, lacking surface treatment, are prone to sedimentation, which in turn leads to cracking during high-temperature tests at 150°C.

[0100] In Comparative Example 6, ordinary talcum powder was used, and the viscosity of the system was greatly reduced, but there was also a sedimentation problem, resulting in poor uniformity of the prepared product. In the high temperature resistance test at 150°C, cracking problems caused by local unevenness occurred.

Claims

1. High thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting compound, characterized by: 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 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 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; The polyether polyol in component A has a number average molecular weight of 375-400 and a functionality of 2 or 3; Modified vegetable oil polyol is a cashew nut shell liquid modified polyol with a functionality of 3.8; The modified hydroxyl-terminated polybutadiene polyol is HTPB with a number average molecular weight of 2800 and a functionality of 2.5; The modified talc powder is modified talc powder HS-335, which is prepared by the following steps: a. Dissolve the surface treatment agent zinc ricinoleate in isopropyl alcohol at a mass ratio of 1:8 to obtain a mixed solution; add talcum powder at a mass ratio of talcum powder to the mixed solution of 3:1; stir the mixture at 2000 rpm for 90 min with a high-speed stirrer; then filter the mixture with a vacuum pump and wash with ethyl acetate to remove excess surface treatment agent to obtain a modified talcum powder wet material; b. Drying the modified talc wet material at 120° C. for 5 h, crushing the lumps with a grinder, and sieving to obtain a modified talc raw material. The maximum particle size of the obtained modified talc raw material is 100 μm; c. The modified talc raw material is divided into 200 mesh, 400 mesh, and 600 mesh according to the mesh size and prepared in a ratio of 2:1:0.5 to obtain the desired modified talc HS-335; The coupling agent is zinc ricinoleate coupling agent; the catalyst is delayed environmentally friendly tin catalyst; The anti-hydrolysis agent is trimethoxy(3-(glycidylether)propyl)silane.

2. 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.

3. 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 diphenoxyphosphorus oxide.

4. The high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting compound according to claim 1, wherein: The water absorbent is Dibaa30X; the anti-settling agent is BYK-410.

5. 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.

6. A method for preparing the high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Preparation of component A: After mixing polyether polyol, modified vegetable oil polyol, modified hydroxyl-terminated polybutadiene polyol, small molecule chain extender, modified talc and flame retardant, dehydrate to a moisture content of less than 0.05%, then cool to 50-60°C, add coupling agent, catalyst, anti-hydrolysis agent, water absorbent, defoaming agent and anti-settling agent in sequence, grind and stir thoroughly, vacuum to remove mechanical bubbles and then encapsulate to obtain component A of the potting compound; (2) Preparation of component B: 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 compound; (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 high thermal conductivity, hydrolysis-resistant and flame-retardant polyurethane potting adhesive is obtained.

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