A kind of hot melt epoxy adhesive oil and preparation method thereof

Abstract

The invention provides a hot-melt epoxy adhesive layer oil and a preparation method thereof. The hot-melt epoxy adhesive layer oil comprises a main agent A component and a curing agent B component. The main agent A component comprises, by weight, 80 to 95 parts of bisphenol A epoxy resin and 5 to 20 parts of a flexible epoxy diluent. The curing agent B component comprises, by weight, 10.5 to 16.7 parts of a monoalcohol primary amine, 33.1 to 53 parts of a toughening curing agent and 34.4 to 56.4 parts of a high-temperature crosslinking agent. The toughening curing agent is prepared by reacting a monoalcohol primary amine, a bisphenol A epoxy resin, a terminal hydroxyl fatty diol and a catalyst in a molar ratio of 2:2:1:(0.1 to 0.5). The high-temperature crosslinking agent is prepared by reacting a monobasic fatty primary amine, a flexible epoxy diluent, a terminal hydroxyl fatty diol and a catalyst in a molar ratio of (3 to 5):(3 to 5):1:(0.1 to 0.5). The invention also provides a preparation method for the hot-melt epoxy adhesive layer oil. The hot-melt epoxy adhesive layer oil prepared by the invention has the advantages of high-temperature hot melting, second-order curing, high tensile strength, high elasticity and strong bonding, and can significantly enhance the bonding force between the base layer and the paving layer.

Description

Technical Field

[0001] The invention relates to the technical field of adhesives for steel bridge deck paving, in particular to a hot-melt epoxy adhesive layer oil and a preparation method thereof. Background Art

[0002] In recent years, the rapid development of my country's economy has driven the rapid development of steel box girder bridge construction. However, the increasing traffic volume and vehicle load have aggravated the damage to the steel bridge deck, resulting in more and more traffic accidents, personal injuries and property losses. How to improve the quality of steel bridge decks has attracted more and more attention.

[0003] The quality of steel bridge decks depends largely on the quality of the tack coat, because the tack coat is the middle layer that bonds the lower steel structure and the upper asphalt mixture pavement. Once the tack coat is damaged on a large scale, the upper and lower layers will be seriously separated, and the bridge will not be able to be opened to traffic normally. The rapidly developing reality requires that the tack coat used for steel bridge decks must have excellent construction performance, tensile strength, elasticity and bonding properties. my country generally uses epoxy asphalt as the tack coat, but its performance can no longer meet the new requirements. At present, the new generation of second-stage curing hot-melt epoxy tack coat can meet the new requirements, but the material and technology are now monopolized by Japan's Modernization Corporation. Domestic related research is still in the experimental stage and there are no finished products. The second-stage curing hot-melt epoxy tack coat oil undergoes a first-stage curing at room temperature after paving to form a thermoplastic polymer with a certain strength. This prevents the subsequent paving of asphalt mixture from being damaged by the rolling of paving vehicles and sticking to the wheels. At the same time, it can be co-melted and mixed with the hot asphalt mixture during pouring and undergo a second-stage curing to form a cross-linked network structure, which not only greatly improves the bonding performance of the tack coat oil and the upper and lower layers, but also overcomes the technical difficulties of paving.

[0004] The second-stage curing hot-melt epoxy tack coat oil successfully solved the problems of poor adhesion between the upper and lower layers, damage caused by paving vehicles and wheel sticking in the paving of steel bridge decks. Therefore, the research and development of second-stage curing hot-melt epoxy tack coat oil for steel bridge decks is of great significance to improving the quality of steel bridge decks and breaking the foreign monopoly.

[0005] In view of this, the inventor specially designed a hot-melt epoxy adhesive oil and a preparation method thereof, and this case was thus generated. Summary of the invention

[0006] In order to solve the above problems, the technical solution of the present invention is as follows: A hot melt epoxy adhesive layer oil, comprising a main agent A component and a curing agent B component, wherein the main agent A component comprises: 80-95 parts of bisphenol A epoxy resin, 5-20 parts of flexible epoxy diluent, and the curing agent B component comprises: 10.5-16.7 parts of monoalcohol primary amine, 33.1-53 parts of toughening curing agent, and 34.4-56.4 parts of high temperature crosslinking agent. The mass ratio of the main agent component A to the curing agent component B is 1:1; The toughening curing agent is prepared according to the following raw material ratio: the molar ratio of monoalcohol primary amine, bisphenol A type epoxy resin, terminal hydroxy fatty diol, and catalyst is 2:2:1:(0.1~0.5); The high temperature crosslinking agent is prepared according to the following raw material ratio: the molar ratio of monobasic fatty primary amine, flexible epoxy diluent, terminal hydroxy fatty diol, and catalyst is (3-5):(3-5):1:(0.1-0.5).

[0007] Furthermore, the bisphenol A epoxy resin is one of E54, E51, E44, or a mixture of any two or more thereof.

[0008] Furthermore, the flexible epoxy diluent is one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, or a mixture of any two or more thereof.

[0009] Furthermore, the monoalcohol primary amine is one of ethanolamine, n-propanolamine, isopropanolamine, 4-amino-1-butanol, 2-amino-1-butanol, 3-amino-1-butanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-2-propanol, and diglycolamine, or a mixture of any two or more thereof.

[0010] Furthermore, the terminal hydroxy fatty diol is one of 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,18-octadecanediol, or a mixture of any two or more thereof.

[0011] Furthermore, the monovalent fatty primary amine is one of hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, octadecylamine and oleylamine, or a mixture of any two or more thereof.

[0012] Furthermore, the catalyst is one of pyridine, triethylamine, N,N-dimethylbenzylamine, triphenylphosphine, or a mixture of any two or more thereof.

[0013] The present invention also provides a method for preparing a hot-melt epoxy adhesive layer oil, comprising the following steps: S1. Preparation of toughening curing agent: under nitrogen protection, bisphenol A epoxy resin, terminal hydroxy fatty diol and catalyst are mixed and heated to 90-120°C, kept under reflux and reacted for 3-6 hours until the ring-opening rate of epoxy group reaches 50%, the reaction is stopped and the material is kept at 60-100°C to form a spare material, and the ring-opening rate of epoxy group is tested according to GB / T 1677-2008 "Determination of Epoxy Value of Plasticizer"; under nitrogen protection, monoalcohol primary amine is heated to 60-100°C, and the spare material in the previous step is slowly added thereto, and the addition is completed within 4-8 hours, and the reaction is stopped after the constant temperature reaction for 1 hour to obtain a toughening curing agent; S2. Preparation of high-temperature crosslinking agent: under nitrogen protection, a flexible epoxy diluent, a terminal hydroxyl fatty diol and a catalyst are mixed and heated to 100-140°C, and reflux is maintained for 4-8 hours until the ring-opening rate of the epoxy group reaches 50%, the reaction is stopped and the material is maintained at 80-120°C to form a standby material, and the ring-opening rate of the epoxy group is tested in accordance with GB / T 1677-2008 "Determination of Epoxy Value of Plasticizers"; under nitrogen protection, a monobasic fatty primary amine is heated to 80-120°C, and the standby material in the previous step is slowly added thereto, and the addition is completed within 6-10 hours, and the reaction is stopped after the constant temperature reaction for 1 hour to obtain a high-temperature crosslinking agent; S3. Preparation of hot-melt epoxy adhesive oil: Stir bisphenol A epoxy resin and flexible epoxy diluent at 80°C for 1 hour and mix them evenly to obtain main agent component A; stir monoalcohol primary amine, toughening curing agent and high-temperature cross-linking agent at 80°C for 1 hour and mix them evenly to obtain curing agent component B; stir and mix main agent component A and curing agent component B evenly to obtain hot-melt epoxy adhesive oil.

[0014] The beneficial effects of the present invention are as follows: 1. The monoalcohol primary amine in component B has a small molecular weight and contains hydroxyl groups. The nitrogen has only two active hydrogens that can react with epoxy. Therefore, it can rapidly undergo a first-order curing reaction with epoxy resin at room temperature and under the promotion of hydroxyl groups to form a thermoplastic polymer, which quickly reaches surface dryness and has a certain strength, making it convenient for subsequent paving of the upper layer of asphalt mixture.

[0015] 2. The toughening curing agent in component B contains epoxy resin components, monoalcohol primary amine components and terminal hydroxy fatty diol components. It contains only two active hydrogens on nitrogen that can react with epoxy. Therefore, it has good compatibility with epoxy resin and can undergo a first-order curing reaction with epoxy resin at room temperature to form a thermoplastic polymer. It also has a certain flexibility and can lower the melting point to facilitate full co-melting and mixing when paving asphalt mixtures, thereby enhancing the bonding performance of the tack coat oil to the upper and lower layers.

[0016] 3. The high-temperature cross-linking agent in component B contains a monovalent fatty primary amine component, a flexible epoxy diluent component and a terminal hydroxy fatty diol component. It contains 3 to 5 active hydrogens on the nitrogen that can react with epoxy. It has more flexibility and fat components, so its reaction activity is low. It can only undergo a second-order curing reaction with the epoxy resin at high temperature to form a thermosetting polymer. It has excellent elasticity and can enhance the tensile properties of the tack coat oil. In addition, it can also lower the melting point to facilitate full eutectic and mixing when paving asphalt mixtures, thereby enhancing the bonding performance of the tack coat oil to the upper and lower layers. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] in: Figure 1 This is a graph showing the experimental data of the surface drying time at 25°C of each embodiment of the present invention; Figure 2 This is a graph of experimental data of the curing time at 160° C. of various embodiments of the present invention; Figure 3 28d tensile strength experimental data diagram of various embodiments of the present invention; Figure 4 28d elongation at break experimental data diagram of various embodiments of the present invention; Figure 5 It is a graph of experimental data of bonding strength to steel plate at 28d for various embodiments of the present invention. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer and more understandable, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example

[0020] (1) Under nitrogen protection, 2 mol of E54, 1 mol of 1,6-hexanediol, and 0.2 mol of triethylamine were mixed and heated to 90°C. After reflux and reaction for 3 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 60°C to form a spare material; under nitrogen protection, 2 mol of ethanolamine was heated to 60°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 4 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a toughening curing agent; (2) Under nitrogen protection, 3 mol of ethylene glycol diglycidyl ether, 1 mol of 1,6-hexanediol, and 0.3 mol of triethylamine were mixed and heated to 100°C. After reflux and reaction for 4 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 80°C to form a standby material; under nitrogen protection, 3 mol of hexylamine was heated to 80°C, and the standby material in the previous step was slowly added thereto. The addition was completed within 6 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a high-temperature crosslinking agent; (3) Stir 80g of E54 and 20g of ethylene glycol diglycidyl ether at 80℃ for 1h and mix them evenly to obtain the main agent component A; stir 11.7g of ethanolamine, 39.7g of toughening curing agent and 48.6g of high temperature cross-linking agent at 80℃ for 1h and mix them evenly to obtain the curing agent component B; stir and mix 100g of the main agent component A and 100g of the curing agent component B evenly to obtain the hot melt epoxy adhesive. Example

[0021] 95g of E54 and 5g of ethylene glycol diglycidyl ether were stirred at 80°C for 1h and mixed evenly to obtain the main agent component A; 10.5g of ethanolamine, 33.1g of the toughening curing agent prepared in Example 1, and 56.4g of the high-temperature cross-linking agent prepared in Example 1 were stirred at 80°C for 1h and mixed evenly to obtain the curing agent component B; 100g of the main agent component A and 100g of the curing agent component B were stirred and mixed evenly to obtain a hot-melt epoxy adhesive. Example

[0022] (1) Under nitrogen protection, 5 mol of ethylene glycol diglycidyl ether, 1 mol of 1,6-hexanediol, and 0.5 mol of triethylamine were mixed and heated to 110°C. After reflux and reaction for 6 hours, the epoxy group ring opening rate reached 50%, and the reaction was stopped and the material was kept at 110°C to form a spare material; under nitrogen protection, 5 mol of octadecylamine was heated to 80°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 8 hours, and the reaction was kept at a constant temperature for 1 hour, and then the reaction was stopped to obtain a high-temperature crosslinking agent; (2) 12.6 g of ethanolamine, 53.0 g of the toughening curing agent prepared in Example 1, and 34.4 g of a high-temperature crosslinking agent were stirred at 80°C for 1 h and mixed evenly to obtain a curing agent component B; 100 g of the main agent component A prepared in Example 1 and 100 g of the curing agent component B were stirred and mixed evenly to obtain a hot-melt epoxy adhesive. Example

[0023] (1) Under nitrogen protection, 2 mol of E44, 1 mol of 1,18-octadecanediol, and 0.3 mol of N,N-dimethylbenzylamine were mixed and heated to 120°C. After reflux and reaction for 6 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 100°C to form a spare material; under nitrogen protection, 2 mol of diglycolamine was heated to 100°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 8 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a toughening curing agent; (2) Under nitrogen protection, 5 mol of polypropylene glycol diglycidyl ether, 1 mol of 1,18-octadecanediol, and 0.5 mol of N,N-dimethylbenzylamine were mixed and heated to 140°C. After reflux and reaction for 8 hours, the epoxy group ring opening rate reached 50%, and the reaction was stopped and the material was kept at 120°C to form a spare material; under nitrogen protection, 5 mol of octadecylamine was heated to 120°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 10 hours, and the reaction was kept at a constant temperature for 1 hour, and then the reaction was stopped to obtain a high-temperature crosslinking agent; (3) Stir 80g of E44 and 20g of polypropylene glycol diglycidyl ether at 80℃ for 1h and mix them evenly to obtain the main agent component A; stir 16.4g of diglycolamine, 46.4g of toughening curing agent and 37.2g of high temperature cross-linking agent at 80℃ for 1h and mix them evenly to obtain the curing agent component B; stir and mix 100g of the main agent component A and 100g of the curing agent component B evenly to obtain the hot melt epoxy adhesive. Example

[0024] (1) Under nitrogen protection, 2 mol of E51, 1 mol of 1,12-dodecanediol, and 0.3 mol of N,N-dimethylbenzylamine were mixed and heated to 100°C. After reflux and reaction for 5 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 80°C to form a spare material; under nitrogen protection, 2 mol of n-propanolamine was heated to 80°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 6 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a toughening curing agent; (2) Under nitrogen protection, 4 mol of hexanediol diglycidyl ether, 1 mol of 1,12-dodecanediol, and 0.4 mol of N,N-dimethylbenzylamine were mixed and heated to 120°C. After reflux and reaction for 6 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 100°C to form a spare material; under nitrogen protection, 4 mol of dodecylamine was heated to 100°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 8 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a high-temperature crosslinking agent; (3) Stir 90g of E51 and 10g of hexanediol diglycidyl ether at 80°C for 1h and mix them evenly to obtain the main agent component A; stir 13.9g of n-propanolamine, 43.5g of toughening curing agent and 42.6g of high-temperature cross-linking agent at 80°C for 1h and mix them evenly to obtain the curing agent component B; stir and mix 100g of the main agent component A and 100g of the curing agent component B evenly to obtain the hot-melt epoxy adhesive. Example

[0025] (1) Under nitrogen protection, 2 mol of E51, 1 mol of 1,8-octanediol, and 0.2 mol of triphenylphosphine were mixed and heated to 100°C. After reflux and reaction for 4 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 80°C to form a spare material; under nitrogen protection, 2 mol of 4-amino-1-butanol was heated to 80°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 6 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a toughening curing agent; (2) Under nitrogen protection, 4 mol of butanediol diglycidyl ether, 1 mol of 1,8-octanediol, and 0.2 mol of triphenylphosphine were mixed and heated to 110°C. After reflux and reaction for 5 hours, the epoxy group ring opening rate reached 50%. The reaction was stopped and the material was kept at 90°C to form a spare material; under nitrogen protection, 4 mol of octylamine was heated to 90°C, and the spare material in the previous step was slowly added thereto. The addition was completed within 7 hours. The reaction was kept at a constant temperature for 1 hour and then the reaction was stopped to obtain a high-temperature crosslinking agent; (3) Stir 85g of E51 and 15g of butanediol diglycidyl ether at 80°C for 1h and mix them evenly to obtain the main agent component A; stir 16.7g of 4-amino-1-butanol, 42.4g of toughening curing agent and 42.6g of high-temperature cross-linking agent at 80°C for 1h and mix them evenly to obtain the curing agent component B; stir 100g of the main agent component A and 100g of the curing agent component B to obtain a hot-melt epoxy adhesive.

[0026] Comparative Example 1 70g of E54 and 30g of ethylene glycol diglycidyl ether were stirred at 80°C for 1h and mixed evenly to obtain the main agent component A; 100g of the main agent component A and 100g of the curing agent component B prepared in Example 1 were stirred and mixed evenly to obtain a hot-melt epoxy adhesive layer oil.

[0027] Comparative Example 2 11.7 g of ethanolamine, 70 g of the toughening curing agent prepared in Example 1, and 18.3 g of the high-temperature cross-linking agent prepared in Example 1 were stirred at 80° C. for 1 hour and mixed evenly to obtain the curing agent B component; 100 g of the main agent A component prepared in Example 1 and 100 g of the curing agent B component were stirred and mixed evenly to obtain a hot-melt epoxy adhesive oil.

[0028] Comparative Example 3 11.7 g of ethanolamine, 18.3 g of the toughening curing agent prepared in Example 1, and 70 g of the high-temperature cross-linking agent prepared in Example 1 were stirred at 80° C. for 1 hour and mixed evenly to obtain the curing agent B component; 100 g of the main agent A component prepared in Example 1 and 100 g of the curing agent B component were stirred and mixed evenly to obtain a hot-melt epoxy adhesive oil.

[0029] Comparative Example 4 9 g of ethanolamine, 42.4 g of the toughening curing agent prepared in Example 1, and 48.6 g of the high-temperature cross-linking agent prepared in Example 1 were stirred at 80° C. for 1 hour and mixed evenly to obtain the curing agent B component; 100 g of the main agent A component prepared in Example 1 and 100 g of the curing agent B component were stirred and mixed evenly to obtain a hot-melt epoxy adhesive.

[0030] Comparative Example 5 (1) Under nitrogen protection, 2 mol of ethylene glycol diglycidyl ether, 1 mol of 1,6-hexanediol, and 0.3 mol of triethylamine were mixed and heated to 100°C. After reflux and reaction for 3 hours, the epoxy group ring opening rate reached 50%, and the reaction was stopped and the material was kept at 80°C to form a standby material; under nitrogen protection, 2 mol of hexylamine was heated to 80°C, and the standby material in the previous step was slowly added thereto. The addition was completed within 5 hours, and the reaction was kept at a constant temperature for 1 hour, and then the reaction was stopped to obtain a high-temperature crosslinking agent; (2) 11.7 g of ethanolamine, 39.7 g of the toughening curing agent prepared in Example 1, and 48.6 g of the high-temperature cross-linking agent were stirred at 80°C for 1 h and mixed evenly to obtain the curing agent B component; 100 g of the main agent A component prepared in Example 1 and 100 g of the curing agent B component were stirred and mixed evenly to obtain a hot-melt epoxy adhesive.

[0031] Comparative Example 6 (1) Under nitrogen protection, 6 mol of ethylene glycol diglycidyl ether, 1 mol of 1,6-hexanediol, and 0.3 mol of triethylamine were mixed and heated to 100°C. After reflux and reaction for 8 hours, the epoxy group ring opening rate reached 50%, and the reaction was stopped and the material was kept at 80°C to form a standby material; under nitrogen protection, 6 mol of hexylamine was heated to 80°C, and the standby material in the previous step was slowly added thereto. The addition was completed within 12 hours, and the reaction was kept at a constant temperature for 1 hour, and then the reaction was stopped to obtain a high-temperature crosslinking agent; (2) 11.7 g of ethanolamine, 39.7 g of the toughening curing agent prepared in Example 1, and 48.6 g of the high-temperature cross-linking agent were stirred at 80°C for 1 h and mixed evenly to obtain the curing agent B component; 100 g of the main agent A component prepared in Example 1 and 100 g of the curing agent B component were stirred and mixed evenly to obtain a hot-melt epoxy adhesive.

[0032] Comparative Example 7 100 g of the main agent component A prepared in Example 1 and 80 g of the curing agent component B prepared in Example 1 were stirred and mixed uniformly to prepare a hot melt epoxy adhesive layer oil.

[0033] Comparative Example 8 100 g of the main agent component A prepared in Example 1 and 120 g of the curing agent component B prepared in Example 1 were stirred and mixed uniformly to prepare a hot melt epoxy adhesive layer oil.

[0034] Comparative Example 9 100 g of KD-HYP main agent A component of the second-stage curing hot-melt epoxy adhesive oil produced by Japan Modern Chemical Industry Co., Ltd. and 100 g of KD-HYP curing agent B component were stirred and mixed uniformly to prepare a hot-melt epoxy adhesive oil.

[0035] The tack coat oils prepared in the above embodiments and comparative examples were tested for their 25°C curing surface drying time, 20min hot melting condition and curing time at 160°C, 28d tensile strength (25°C), 28d elongation at break (25°C) (tested in accordance with GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"), and 28d bonding strength to steel plate (25°C) (tested in accordance with the "Guidelines for Design and Construction of Highway Steel Box Girder Bridge Deck Pavement"), and the results are as follows: Figures 1 to 5 shown.

Claims

1. A hot melt epoxy adhesive, characterized in that: The invention comprises a main agent component A and a curing agent component B. In parts by weight, the main agent component A comprises: 80-95 parts of bisphenol A epoxy resin and 5-20 parts of flexible epoxy diluent; the curing agent component B comprises: 10.5-16.7 parts of monoalcohol primary amine, 33.1-53 parts of toughening curing agent and 34.4-56.4 parts of high temperature crosslinking agent; in: The mass ratio of the main agent component A to the curing agent component B is 1:1; The toughening curing agent is prepared according to the following raw material ratio: the molar ratio of monoalcohol primary amine, bisphenol A type epoxy resin, terminal hydroxy fatty diol, and catalyst is 2:2:1:(0.1~0.5); The high temperature crosslinking agent is prepared according to the following raw material ratio: the molar ratio of monobasic fatty primary amine, flexible epoxy diluent, terminal hydroxy fatty diol, and catalyst is (3-5):(3-5):1:(0.1-0.5).

2. A hot melt epoxy adhesive according to claim 1, characterized in that: The bisphenol A epoxy resin is one of E54, E51, and E44, or a mixture of any two or more thereof.

3. A hot melt epoxy adhesive according to claim 1, characterized in that: The flexible epoxy diluent is one of ethylene glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, or a mixture of any two or more thereof.

4. A hot melt epoxy adhesive according to claim 1, characterized in that: The monoalcohol primary amine is one of ethanolamine, n-propanolamine, isopropanolamine, 4-amino-1-butanol, 2-amino-1-butanol, 3-amino-1-butanol, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-2-propanol, and diglycolamine, or a mixture of any two or more thereof.

5. A hot melt epoxy adhesive according to claim 1, characterized in that: The terminal hydroxy fatty diol is one of 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, and 1,18-octadecanediol, or a mixture of any two or more thereof.

6. A hot melt epoxy adhesive according to claim 1, characterized in that: The monovalent fatty primary amine is one of hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, octadecylamine and oleylamine, or a mixture of any two or more thereof.

7. A hot melt epoxy adhesive according to claim 1, characterized in that: The catalyst is one of pyridine, triethylamine, N,N-dimethylbenzylamine and triphenylphosphine or a mixture of any two or more thereof.

8. A method for preparing a hot melt epoxy adhesive according to any one of claims 1 to 7, characterized in that: The steps include: S1. Preparation of toughening curing agent: Mix bisphenol A epoxy resin, terminal hydroxy fatty diol and catalyst under nitrogen protection and heat to 90-120°C, keep reflux and react for 3-6 hours until the ring-opening rate of epoxy group reaches 50%, stop the reaction and keep the material at 60-100°C for standby; Heat monoalcohol primary amine to 60-100°C under nitrogen protection, slowly add the standby material in the previous step, add it for 4-8 hours, keep constant temperature reaction for 1 hour and then stop the reaction to obtain toughening curing agent; S2. Preparation of high-temperature crosslinking agent: under nitrogen protection, a flexible epoxy diluent, a terminal hydroxyl fatty diol and a catalyst are mixed and heated to 100-140°C, and reflux is maintained for 4-8 hours until the ring-opening rate of the epoxy group reaches 50%, the reaction is stopped and the material is maintained at 80-120°C for standby use; under nitrogen protection, a monobasic fatty primary amine is heated to 80-120°C, and the standby material in the previous step is slowly added thereto, and the addition is completed over 6-10 hours, and the reaction is maintained at a constant temperature for 1 hour and then the reaction is stopped to obtain a high-temperature crosslinking agent; S3. Prepare hot-melt epoxy adhesive oil: stir bisphenol A epoxy resin and flexible epoxy diluent at 80°C for 1 hour and mix them evenly to obtain main agent component A; stir monoalcohol primary amine, toughening curing agent and high-temperature cross-linking agent at 80°C for 1 hour and mix them evenly to obtain curing agent component B; stir and mix main agent component A and curing agent component B evenly to obtain hot-melt epoxy adhesive layer.

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