Quick-curing polyurethane structural adhesive and preparation method thereof

Abstract

The invention relates to the field of polyurethane sealants, and discloses a fast-curing polyurethane structural adhesive and a preparation method thereof. The rapid curing polyurethane structural adhesive is composed of a component A and a component B, wherein the component A is composed of the following raw materials in parts by weight: 40-50 parts of an isocyanate-terminated polyurethane prepolymer, 0-400 parts of a heat-conducting filler, 6-10 parts of a stabilizer, 0.5-1.5 parts of a dewatering agent and 1-3 parts of an antioxidant; the component B is prepared from the following raw materials in parts by weight: 10 to 15 parts of polycaprolactone polyol, 8 to 12 parts of polyether polyol, 0 to 400 parts of heat-conducting filler, 1 to 2 parts of dispersing agent and 0.1 to 2 parts of catalyst. The preparation method comprises the following steps: respectively heating the raw materials of the component A and the raw materials of the component B, vacuumizing and mixing. The polyurethane structural adhesive provided by the invention has good curing efficiency, adhesion and thermal conductivity, provides enough assembling time and adhesion for the power battery pack, can be rapidly cured after being assembled, and is high in assembling efficiency.

Description

Technical Field

[0001] The present invention relates to the field of polyurethane sealants, and more specifically, to a fast-curing polyurethane structural adhesive and a preparation method thereof. Background Art

[0002] As the power source of new energy vehicles, the stability of the performance of power battery packs directly affects the driving state of new energy vehicles. The power battery pack is assembled by several batteries in parallel. In the packaging process of power battery packs, polyurethane structural adhesive plays a vital role. It not only needs to have good thermal conductivity to ensure that the heat generated by the battery during operation can be effectively transferred and dissipated, but also requires fast curing and excellent bonding properties to improve assembly quality and production efficiency.

[0003] Polyurethane structural adhesive is a type of block copolymer made from isocyanate, polyester polyol, polyether polyol and catalyst. It has adjustable hardness and has excellent wear resistance, elasticity, chemical corrosion resistance, adhesion and shock absorption, etc. However, the thermal conductivity of pure polyurethane resin is low, only 0.18~0.20W / (mk), which does not meet the thermal conductivity requirements of power battery pack packaging.

[0004] In order to improve the thermal conductivity of polyurethane structural adhesive, it is usually necessary to add thermal conductive fillers to polyurethane structural adhesive. Although the addition of thermal conductive fillers improves the thermal conductivity of polyurethane structural adhesive, it is difficult to meet the requirements of the battery pack assembly process for operation time and curing speed. If the curing speed is fast, the operation time of polyurethane structural adhesive during assembly is short; if the operation time can be met, the curing speed is slow, and when the power battery pack is assembled on the production line, it cannot be cured in time to reach a certain initial adhesion to meet the requirements of the next process, thereby reducing the assembly efficiency of the power battery pack. Summary of the invention

[0005] In order to solve the problem that polyurethane structural adhesive cannot well balance thermal conductivity and meet the requirements of the power battery pack assembly process on operation time and curing speed, thereby reducing the assembly efficiency of the power battery pack, the present application provides a fast-curing polyurethane structural adhesive and a preparation method thereof.

[0006] In a first aspect, the present application provides a fast curing polyurethane structural adhesive, which adopts the following technical solution: A fast-curing polyurethane structural adhesive consists of a component A and a component B. The component A consists of the following raw materials in parts by weight: 40-50 parts of isocyanate-terminated polyurethane prepolymer, 0-400 parts of thermal conductive filler, 6-10 parts of stabilizer, 0.5-1.5 parts of water remover, and 1-3 parts of antioxidant; the component B consists of the following raw materials in parts by weight: 10-15 parts of polycaprolactone polyol, 8-12 parts of polyether polyol, 0-400 parts of thermal conductive filler, 1-2 parts of dispersant, and 0.1-2 parts of catalyst.

[0007] By adopting the above technical scheme, the polyurethane structural adhesive of the present application is a two-component adhesive, wherein component A is composed of an isocyanate-terminated polyurethane prepolymer, a stabilizer, a water scavenger and an antioxidant, and under the action of the stabilizer and the isocyanate-terminated polyurethane prepolymer, when a thermally conductive filler is added, the thermally conductive filler can be dispersed; component B is composed of polycaprolactone polyol, polyether polyol, a dispersant and a catalyst, and under the action of the dispersant, polycaprolactone polyol and polyether polyol, when a thermally conductive filler is added, the thermally conductive filler and the catalyst can be uniformly dispersed; component A and component B After the components are mixed, under the action of the catalyst and the antioxidant, each component can slowly and stably cross-link the reaction for a long time, providing sufficient operating time for the assembly of the power battery pack. After a certain amount of heat is accumulated after a period of reaction, the catalytic ability of the catalyst is rapidly improved, and the isocyanate-terminated polyurethane prepolymer is further coordinated to accelerate the cross-linking reaction of each component to achieve a certain bonding strength. After the power battery pack is assembled, it can be quickly cured, so that the fast-curing polyurethane structural adhesive has a curing efficiency of first slow and then fast, and the polyurethane structural adhesive prepared in this way has a stable curing rate and bonding stability. Further preferably, the amount of the thermally conductive filler of component A is 25-35 parts, and the amount of the thermally conductive filler of component B is 15-25 parts. Adding a better amount of thermally conductive filler can improve the thermal conductivity of the polyurethane structural adhesive while also having good tensile shear strength, which can effectively improve the heat dissipation effect and assembly efficiency of the power battery pack.

[0008] Preferably, the isocyanate-terminated polyurethane prepolymer is prepared from the following raw materials in parts by weight: 50-60 parts of diisocyanate Polyether polyol 10-20 parts 5-8 parts of hydroxyl-terminated polybutadiene 4-6 parts of diethylene glycol 1-3 parts of 3-aminopropyltrihydroxysilane Catalyst 0.2-0.4 parts.

[0009] By adopting the above technical scheme, diisocyanate provides isocyanate group, polyether polyol provides alcohol hydroxyl group, and polymerization reaction is carried out under the action of catalyst, terminal hydroxyl polybutadiene, diethylene glycol and 3-aminopropyltrihydroxysilane in a preferred dosage ratio are added to the reaction system, and vinyl, long-chain ether group and siloxy chain segment are introduced into the reaction system. The obtained isocyanate-terminated polyurethane can significantly improve the dispersion performance of thermal conductive filler in polyurethane structural adhesive, improve the problem that the addition of thermal conductive filler reduces the curing efficiency of polyurethane structural adhesive, and at the same time can stably carry out further cross-linking reaction with other components, thereby improving the heat dissipation performance, rapid curing performance and bonding performance of the obtained polyurethane structural adhesive, thereby improving the assembly stability and production efficiency of power battery packs.

[0010] Preferably, the isocyanate-terminated polyurethane prepolymer is prepared by the following steps: adding diisocyanate, polyether polyol and catalyst into a reaction device, vacuumizing to react, and then adding terminal hydroxyl polybutadiene, diethylene glycol and 3-aminopropyltrihydroxysilane to react to prepare the isocyanate-terminated polyurethane prepolymer.

[0011] By adopting the above technical scheme, diisocyanate and polyether polyol are first reacted under the action of a catalyst to introduce a polyether segment on the isocyanate segment, and then terminal hydroxyl polybutadiene, diethylene glycol and 3-aminopropyltrihydroxysilane are added to extend the isocyanate chain, and vinyl, long-chain ether and siloxy segments are introduced to prepare an isocyanate-terminated polyurethane prepolymer, thereby improving the reaction efficiency and quality of the isocyanate polyurethane prepolymer, thereby improving the bonding performance and curing efficiency of the polyurethane structural adhesive.

[0012] Preferably, the thermally conductive fillers of the component A and the component B are both composed of aluminum oxide, boron nitride and magnesium oxide in a weight ratio of 1:(2-3):(0.2-0.4).

[0013] By adopting the above technical solution, using aluminum oxide, boron nitride and magnesium oxide in an optimal dosage ratio as thermally conductive fillers, the three thermally conductive fillers can produce a good synergistic effect and be evenly dispersed in the polyurethane structural adhesive system, thereby improving the rapid curing performance and excellent bonding performance of the polyurethane structural adhesive while improving the thermal conductivity.

[0014] Preferably, the stabilizer is composed of trimethylolpropane trimethacrylate and 3-isocyanatepropyltriethoxysilane in a weight ratio of 1:(0.5-1.5).

[0015] By adopting the above technical scheme, with trimethylolpropane trimethacrylate and 3-isocyanatepropyltriethoxysilane in an optimal dosage ratio as stabilizers, the cross-linking stability of components A and B can be improved, forming a uniform macromolecular network system, so that the thermal conductive filler is evenly interwoven and dispersed, thereby improving the thermal conductivity and curing stability of the polyurethane structural adhesive, ensuring the stability and reliability of the polyurethane structural adhesive during use.

[0016] Preferably, the dispersant is composed of dibutyl itaconate and cocoglyceryl in a weight ratio of (3-4):1.

[0017] By adopting the above technical scheme, using dibutyl itaconate and glyceryl cocoate in an optimal dosage ratio as dispersants, the dispersion uniformity of each component can be improved, the fluidity of the polyurethane structural adhesive system can be improved, and then the curing efficiency of the polyurethane structural adhesive can be improved, so that the polyurethane structural adhesive has good thermal conductivity and good bonding performance.

[0018] Preferably, the catalyst is an organotin catalyst, one or a combination of organotin catalysts.

[0019] By adopting the above technical solution, the above catalyst can effectively control the curing rate of the polyurethane structural adhesive, so that the polyurethane structural adhesive has uniform curing performance, providing suitable operation time and fitting performance for the assembly of the power battery pack, and can further quickly cure after the assembly is completed, thereby shortening the assembly time of the power battery pack on the production line and improving the assembly stability and production efficiency of the power battery pack.

[0020] Preferably, the dehydrating agent is any one of molecular sieve and anhydrous calcium chloride, and the antioxidant is one of antioxidant 1010, antioxidant 168, antioxidant 1076 and antioxidant 1098 or a combination thereof.

[0021] By adopting the above technical scheme, preferably the above dehydrating agent, not only can the moisture in the polyurethane structural adhesive be effectively removed, but also the system stability of the polyurethane structural adhesive can be maintained; preferably the above antioxidant can enhance the antioxidant performance of the polyurethane structural adhesive, thereby extending the service life of the polyurethane structural adhesive.

[0022] Preferably, the dosage ratio of the component A to the component B is (0.9-1.1):1.

[0023] By adopting the above technical solution, the usage ratio of component A and component B is controlled within the range of (0.9-1.1):1, so that the polyurethane structural adhesive can stably cross-link components A and B while ensuring good thermal conductivity, thereby providing operation time and assembly adhesion for the assembly of the power battery pack. After the assembly is completed, it can be quickly cured, thereby improving the assembly stability and production efficiency of the power battery pack.

[0024] In a second aspect, the present application provides a method for preparing a fast-curing polyurethane structural adhesive, using the following technical solution: A method for preparing a fast-curing polyurethane structural adhesive comprises the following steps: heating and vacuumizing isocyanate-terminated polyurethane prepolymer, thermal conductive filler, stabilizer, dehumidifier and antioxidant to uniformly mix and obtain component A; The polycaprolactone polyol, polyether polyol, thermal conductive filler, dispersant and catalyst are heated and vacuumed to mix uniformly to obtain component B.

[0025] By adopting the above technical solution, the preparation method of the fast-curing polyurethane structural adhesive can ensure that component A and component B are fully and evenly mixed, thereby improving the comprehensive performance of the polyurethane structural adhesive. By heating and vacuuming to evenly mix and prepare component A and component B, it is not only possible to effectively remove moisture from the raw materials to avoid affecting the curing effect, but also to ensure that the thermal conductive filler is evenly dispersed, thereby improving the thermal conductivity and curing efficiency of the polyurethane structural adhesive, and having good storage stability.

[0026] In summary, this application has the following beneficial effects: 1. The fast-curing polyurethane structural adhesive of the present application uses isocyanate-terminated polyurethane prepolymer, thermally conductive filler, stabilizer, desiccant and antioxidant as component A, and polycaprolactone polyol, polyether polyol, thermally conductive filler, dispersant and catalyst as component B. The prepared polyurethane structural adhesive is used in power battery pack packaging, providing sufficient operating time and good initial adhesion performance for the assembly of power battery packs. It can be quickly cured after assembly, and while having good thermal conductivity, it also has good curing rate and bonding stability, which can effectively improve the heat dissipation effect and assembly efficiency of the power battery pack.

[0027] 2. The use of isocyanate-terminated polyurethane prepolymers prepared from diisocyanate, polyether polyol, terminal hydroxyl polybutadiene, diethylene glycol, 3-aminopropyltrihydroxysilane and a catalyst can significantly improve the dispersion performance of thermally conductive fillers in polyurethane structural adhesives, and can stably undergo further cross-linking reactions with other components, thereby improving the rapid curing performance and bonding performance of the prepared polyurethane structural adhesive.

[0028] 3. Using trimethylolpropane trimethacrylate and 3-isocyanatepropyltriethoxysilane in an optimal dosage ratio as stabilizers can improve the cross-linking stability of components A and B, form a uniform macromolecular network system, and make the thermal conductive filler evenly interwoven and dispersed, thereby improving the thermal conductivity and curing stability of the polyurethane structural adhesive, ensuring the stability and reliability of the polyurethane structural adhesive during use. DETAILED DESCRIPTION

[0029] The present application is further described in detail below with reference to the embodiments.

[0030] The following are the sources and specifications of some raw materials of this application. The raw materials used in the preparation examples and embodiments of this application can be obtained from the market, including but not limited to the raw materials of the following models and manufacturers. Raw materials with equivalent performance can be used: 1. Hydroxyl-terminated polybutadiene: KMIKE, CAS No. 69102-90-5, hydroxyl value 0.47-0.53 mgKOH / g, content 99%; 2. Alumina: purity 99.99%, spherical alumina, particle size 30-70nm; 3. Boron nitride: purity 99.9%, particle size 100-150nm; 4. Magnesium oxide: purity 99.9%, particle size 30-50nm; 5. Trimethylolpropane trimethacrylate: Lana White, content 99%, CAS No. 3290-92-4; 6. 3-isocyanatepropyltriethoxysilane: Shin-Etsu KBE-9007; 7. Dibutyl itaconate: CAS No. 2155-60-4, content 98%; 8. Molecular sieve: particle size 2-6 microns, model JZ-AZ3, Jiuzhou Chemical.

[0031] Preparation Example of Isocyanate-Terminated Polyurethane Prepolymer Preparation Example 1 Preparation Example 1 discloses an isocyanate-terminated polyurethane prepolymer, which is prepared by the following steps: 5kg of isophorone diisocyanate, 1kg of polytetramethylene ether glycol as a polyether polyol and 0.02kg of a catalyst (stannous octoate) are added to a reactor, the vacuum degree is controlled to be -0.08MPa, the temperature is raised to 75°C, and the reaction is carried out for 1h, and then 0.5kg of terminal hydroxyl polybutadiene, 0.4kg of diethylene glycol and 0.1kg of 3-aminopropyltrihydroxysilane are added, the vacuum degree is continued to be controlled to be -0.08MPa, and the reaction is continued for 30min at a temperature of 75°C to obtain an isocyanate-terminated polyurethane prepolymer; the molecular weight of the polytetramethylene ether glycol is 2000, and the hydroxyl value is 54.7-57.5mg KOH / g.

[0032] Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 1 below for details.

[0033] Table 1 Raw material dosage and preparation conditions of Preparation Examples 1-3 Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that diethylene glycol is replaced by 1,4-butanediol in an equal amount, and the rest is the same as Preparation Example 1.

[0034] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that 3-aminopropyltrihydroxysilane is replaced by an equal amount of vinyltrimethoxysilane, and the rest is the same as Preparation Example 1.

[0035] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that the terminal hydroxyl polybutadiene is replaced by diethylene glycol in an equal amount, and the rest is the same as Preparation Example 1.

[0036] Preparation Example 7 The difference between Preparation Example 7 and Preparation Example 1 is that 3-aminopropyltrihydroxysilane is replaced by diethylene glycol in an equal amount, and the rest is the same as Preparation Example 1. Example

[0037] Example 1 Example 1 discloses a fast curing polyurethane structural adhesive, which is prepared by the following steps: 4 kg of commercially available isocyanate-terminated polyurethane prepolymer, 2.5 kg of thermal conductive filler (composed of aluminum oxide, boron nitride and magnesium oxide in a weight ratio of 1:3:0.2), 0.6 kg of 3-isocyanate propyl triethoxysilane as a stabilizer, 0.1 kg of molecular sieve as a dehydrating agent and 0.1 kg of antioxidant (composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1) were heated to 55°C and the vacuum degree was controlled to -0.08 MPa. 60min to obtain component A; 1kg of polycaprolactone diol as polycaprolactone polyol, 0.8kg of polytetramethylene ether glycol as polyether polyol, 1.5kg of thermal conductive filler (composed of aluminum oxide, boron nitride and magnesium oxide in a weight ratio of 1:3:0.2), 0.1kg of dioctyl phthalate as dispersant and 0.1kg of catalyst (stannous octoate), heated to 55°C, controlled the vacuum degree to -0.08MPa, mixed for 50min to obtain component B; The isocyanate-terminated polyurethane prepolymer is a commercially available MDI type polyurethane prepolymer with an isocyanate content of 7-9%; the molecular weight of the polycaprolactone diol is 2000 and the hydroxyl value is 54-58 mg KOH / g; the molecular weight of the polytetramethylene ether glycol is 2000 and the hydroxyl value is 54.7-57.5 mg KOH / g.

[0038] Example 2-3 The difference between Example 2-3 and Example 1 is that the amount of raw materials used and the preparation conditions are different, see Table 2 below for details.

[0039] Table 2 Raw material dosage and preparation conditions of Examples 1-3 Embodiment 4-10 The difference between Examples 4-10 and Example 1 is that the sources of the isocyanate-terminated polyurethane prepolymer are different, see Table 3 below for details.

[0040] Table 3 Sources of isocyanate-terminated polyurethane prepolymers of Examples 4-10 Embodiment 11 The difference between Example 11 and Example 4 is that the stabilizer is different. The stabilizer in Example 11 consists of trimethylolpropane trimethacrylate and 3-isocyanate propyl triethoxysilane. The amount of trimethylolpropane trimethacrylate is 0.4 kg, and the amount of 3-isocyanate propyl triethoxysilane is 0.2 kg. The rest is the same as Example 4.

[0041] Example 12 The difference between Example 12 and Example 4 is that the stabilizer in Example 12 consists of trimethylolpropane trimethacrylate and 3-isocyanate propyl triethoxysilane, the amount of trimethylolpropane trimethacrylate is 0.2 kg, the amount of 3-isocyanate propyl triethoxysilane is 0.4 kg, and the rest is the same as Example 4.

[0042] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the isocyanate-terminated polyurethane prepolymer is replaced by isophorone diisocyanate in an equal amount, and the other parts are the same as Example 1.

[0043] Performance Testing The following performance tests were conducted on the fast curing polyurethane structural adhesives prepared in Examples 1-12 and Comparative Example 1: 1. Thermal conductivity test: According to the test method in ASTM D 5470, the thermal conductivity (unit: W / (m·K)) of the fast curing polyurethane structural adhesive was tested and the test results were recorded; 2. Operation time detection: Place the fast-curing polyurethane structural adhesive in a constant temperature chamber at 25°C / 50% RH and mix for 10 minutes. After mixing evenly, use an extrusion glue gun to extrude a strip with a width of 2 cm and a thickness of 10 mm. Start timing and touch the strip lightly with your finger. Stop timing when no wire drawing occurs on the strip. Record it as the operable time (unit: min). Keep one decimal place, test and record the test results.

[0044] 3. Initial curing tensile shear strength test: Refer to the test method in GB / T7124-2008 "Determination of tensile shear strength of adhesives" to test the tensile shear strength (unit: MPa) of the fast-curing polyurethane structural adhesive at a curing temperature of 25°C and a curing time of 40 minutes, and test and record the test results; 4. Fully cured tensile shear strength test: Referring to the test method in GB / T7124-2008 "Determination of tensile shear strength of adhesives", the full tensile shear strength (unit: MPa) of the fast-curing polyurethane structural adhesive at a curing temperature of 25°C and a curing time of 7 days was tested, and the test results were recorded.

[0045] The following are the performance test data of the fast-curing polyurethane structural adhesive of Examples 1-12 and Comparative Example 1 of the present application, see Table 4 below for details.

[0046] Table 4 Performance test data of Examples 1-12 and Comparative Example 1 Combining Examples 1-3 and Examples 4-10, Comparative Example 1 and Table 4, it can be concluded that the polyurethane structural adhesive prepared using the isocyanate-terminated polyurethane prepolymer prepared in the present application has a high thermal conductivity, a moderate operating time, a moderate initial tensile shear strength, can quickly position the power battery pack, and can be quickly cured after heating; Compared with Examples 7-10, Example 4 has a thermal conductivity increase of 0.24 W / (m·K), an operating time extension of 2.7 min, and an initial curing tensile shear strength increase of 0.2 MPa. a, the fully cured tensile shear strength is increased by 2.1 MPa, which shows that the synergistic effect of the terminal hydroxybutadiene, diethylene glycol, and 3-aminopropyltrihydroxysilane of the present application can significantly improve the thermal conductivity and curing rate of the prepared polyurethane structural adhesive, and can also quickly cure while achieving rapid assembly, thereby improving the assembly efficiency of the product; in Comparative Example 1, the isocyanate-terminated polyurethane prepolymer is replaced with isophorone diisocyanate in equal amounts, and the prepared polyurethane structural adhesive has a longer operating time, and the initial cured tensile shear strength is significantly reduced.

[0047] Combining Example 1 and Example 4, Examples 11-12 and Table 4, it can be concluded that the use of trimethylolpropane trimethacrylate and 3-isocyanatepropyltriethoxysilane in the preferred dosage ratio of the present application as stabilizers and the isocyanate-terminated polyurethane prepolymer prepared in the present application can further enhance the synergistic effect, and can further enhance the thermal conductivity and curing efficiency of the prepared polyurethane structural adhesive.

[0048] The polyurethane structural adhesive of the present application can adjust the addition ratio of the thermally conductive filler, and the amount of the thermally conductive filler can be adjusted between 0 and 400 parts by weight, so that the thermal conductivity of the prepared fast-curing polyurethane structural adhesive can reach 0.1-3W / (m·K), and the operable time at room temperature is 22-32 minutes, and stable bonding performance can be maintained, and the initial bonding performance reaches above 0.7MPa, which can stabilize and position the product; after being fully cured, the product can be given a tensile shear strength of 13.2MPa, which has good assembly stability for the product and improves the assembly efficiency of the product.

[0049] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A fast curing polyurethane structural adhesive, characterized in that: The invention comprises component A and component B, wherein component A comprises the following raw materials in parts by weight: 40-50 parts of isocyanate-terminated polyurethane prepolymer, 0-400 parts of thermal conductive filler, 6-10 parts of stabilizer, 0.5-1.5 parts of dewatering agent and 1-3 parts of antioxidant; and component B comprises the following raw materials in parts by weight: 10-15 parts of polycaprolactone polyol, 8-12 parts of polyether polyol, 0-400 parts of thermal conductive filler, 1-2 parts of dispersant and 0.1-2 parts of catalyst.

2. A fast curing polyurethane structural adhesive according to claim 1, characterized in that: The isocyanate-terminated polyurethane prepolymer is prepared from the following raw materials in parts by weight: 50-60 parts of diisocyanate Polyether polyol 10-20 parts 5-8 parts of hydroxyl-terminated polybutadiene 4-6 parts of diethylene glycol 1-3 parts of 3-aminopropyltrihydroxysilane Catalyst 0.2-0.4 parts.

3. A fast curing polyurethane structural adhesive according to claim 2, characterized in that: The isocyanate-terminated polyurethane prepolymer is prepared by the following steps: adding diisocyanate, polyether polyol and a catalyst into a reaction device, vacuumizing to react, and then adding terminal hydroxyl polybutadiene, diethylene glycol and 3-aminopropyltrihydroxysilane to react to prepare the isocyanate-terminated polyurethane prepolymer.

4. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The thermal conductive fillers of the component A and the component B are both composed of aluminum oxide, boron nitride and magnesium oxide in a weight ratio of 1:(2-3):(0.2-0.4).

5. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The stabilizer is composed of trimethylolpropane trimethacrylate and 3-isocyanate propyl triethoxysilane in a weight ratio of 1:(0.5-1.5).

6. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The dispersant is composed of dibutyl itaconate and glyceryl cocoate in a weight ratio of (3-4):

1.

7. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The catalyst is one or a combination of an organic tin catalyst and an organic bismuth catalyst.

8. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The dehydrating agent is any one of molecular sieve and anhydrous calcium chloride, and the antioxidant is one of antioxidant 1010, antioxidant 168, antioxidant 1076 and antioxidant 1098 or a combination thereof.

9. The fast curing polyurethane structural adhesive according to claim 1, characterized in that: The dosage ratio of the component A to the component B is (0.9-1.1):

1.

10. A method for preparing a fast curing polyurethane structural adhesive according to any one of claims 1 to 9, characterized in that: The following steps are involved: The isocyanate-terminated polyurethane prepolymer, the thermal conductive filler, the stabilizer, the water scavenger and the antioxidant are heated and vacuumed to mix uniformly to prepare component A; The polycaprolactone polyol, polyether polyol, thermal conductive filler, dispersant and catalyst are heated and vacuumed to mix uniformly to obtain component B.

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