Eucommia ulmoides gum modified second-order reaction epoxy adhesive and preparation method thereof

Abstract

The invention discloses a gutta-percha modified second-order reaction epoxy adhesive and a preparation method thereof, the epoxy adhesive is composed of a component A and a component B. The component A comprises epoxidized gutta-percha, liquid epoxy resin, a reactive diluent, an auxiliary agent and the like, and the component B comprises a cardanol modified phenolic aldehyde amine curing agent, a modified polyamide curing agent, vegetable oleic acid, an auxiliary agent and the like. The gutta-percha modified second-order reaction epoxy adhesive disclosed by the invention has the characteristics of second-order reaction characteristic, high flexibility, high bonding strength, greenness, environment friendliness, reproducibility and the like, and is suitable for waterproof bonding between steel and concrete base planes of roads, bridges and the like and asphalt pavement layers.

Description

Technical Field

[0001] This invention belongs to the field of bio-based adhesive materials and their application technology, specifically relating to a second-order reactive epoxy adhesive modified with Eucommia ulmoides gum and its preparation method. Background Technology

[0002] Epoxy adhesives, due to their excellent mechanical properties and chemical stability, are widely used in road and bridge paving projects for waterproof bonding between steel and concrete substrates and asphalt pavement layers. They are key functional materials for achieving the integrity and long-term service performance of pavement structures. Although staged curing epoxy adhesive systems have been developed, allowing for gradual strength development within different temperature ranges to adapt to on-site construction requirements, issues remain regarding excessively high post-curing strength and insufficient flexibility. This leads to stress concentration under alternating temperatures and dynamic load coupling, causing interfacial delamination or pavement cracking. Furthermore, traditional epoxy adhesives largely rely on petroleum-based raw materials; in the context of green and low-carbon development, their sustainability and environmental friendliness urgently need improvement. Summary of the Invention

[0003] In view of the above-mentioned shortcomings, the present invention provides a two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum and its preparation method. The epoxy adhesive has the characteristics of two-stage reaction, high flexibility, high bonding strength, green environmental protection and recyclability, and is suitable for waterproof bonding between steel and concrete base surfaces and asphalt pavement layers in roads, bridges and other projects.

[0004] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: Epoxidized Eucommia ulmoides gum 20-45 parts; 20-50 parts of liquid epoxy resin; 10-40 parts of monofunctional active diluent; 10-40 parts of bifunctional active diluent; 0.5 to 2 parts of coupling agent; Thixotropic agent 0.1~1 part; Defoamer 0.05~0.5 parts; Component B comprises the following components in parts by weight: 10-30 parts of cashew phenol-modified phenolic amine curing agent; 10-30 parts of modified polyamide curing agent; 40-80 parts of vegetable oleic acid; 0.5 to 3 parts of anhydrous citric acid; 0.5 to 4 parts of 2-ethyl-4-methylimidazole; The epoxy value of the epoxidized Eucommia ulmoides gum is 0.7~2.1 mmol / g, and its preparation process includes the following steps: S1. Add Eucommia gum to the mixed solvent and heat to 70°C with stirring until completely dissolved; S2. Introduce nitrogen gas and slowly add a mixed solution of tetraalkylammonium molybdate and tert-butyl hydrogen peroxide dropwise until the epoxy value reaches the required level, then stop the reaction. S3. After cooling to room temperature, add sodium sulfite aqueous solution and stir for 30 minutes. Then add ethanol and continue stirring for 10 minutes. After filtration, washing and drying, epoxidized Eucommia gum is obtained. The mass ratio of component A to component B is 100:60~100.

[0005] According to one aspect of the present invention, in step S1, the Eucommia gum is Eucommia gum with a natural Eucommia gum content of ≥98%, which can be purchased from Shaanxi Mufan Biotechnology Co., Ltd.

[0006] According to one aspect of the present invention, in step S1, the mixed solvent is a mixed solvent of toluene and petroleum ether in a volume ratio of 1:1.

[0007] According to one aspect of the present invention, the amount of tetraalkylammonium molybdate used in step S2 is 0.05 to 0.50% of the mass of Eucommia ulmoides gum.

[0008] According to one aspect of the present invention, the amount of tert-butyl hydroperoxide used in step S2 is 5 to 25% of the mass of Eucommia ulmoides gum.

[0009] According to one aspect of the present invention, the liquid epoxy resin is a liquid bisphenol A type epoxy resin with an epoxy value of 4.2 to 5.3 mmol / g, such as E51 epoxy resin from Sinopec Baling Branch.

[0010] According to one aspect of the present invention, the monofunctional active diluent is one of C8-decyl glycidyl ether, C12-tetradecyl glycidyl ether, C12-tweldedecyl glycidyl ether, or C12-decyl glycidyl ether.

[0011] According to one aspect of the present invention, the bifunctional active diluent is one of neopentyl glycol diglycidyl ether and 1,6-hexanediol diglycidyl ether.

[0012] According to one aspect of the present invention, the plant oleic acid is one of myristic acid, palmitic acid, palmitoleic acid, tung oil acid, and ricinoleic acid.

[0013] According to one aspect of the present invention, the coupling agent is KH560, the thixotropic agent is Evonik Silica AEROSILA200, the defoamer is Anjeka-5680A defoamer from Ezhou Anjikang Technology Co., Ltd., the cashew nut shell modified phenolic amine curing agent is XY-3209 cashew nut shell modified phenolic amine curing agent from Shanghai Xuanyuan New Material Technology Co., Ltd., and the modified polyamide curing agent is TY5324 modified polyamide curing agent from Jining Fangde Chemical Co., Ltd.

[0014] This invention also provides a method for preparing the above-mentioned Eucommia ulmoides gum-modified second-order reactive epoxy adhesive, comprising the following steps: S1. Add epoxidized Eucommia ulmoides gum to monofunctional reactive diluent and difunctional reactive diluent, and heat to 70°C while stirring. After the epoxidized Eucommia ulmoides gum is completely dissolved, add liquid epoxy resin, defoamer and coupling agent, and disperse at high speed for 1 to 2 minutes. Then add thixotropic agent and disperse at high speed for 3 to 5 minutes to obtain component A. S2. Add anhydrous citric acid to cashew phenol-modified phenolic amine curing agent and modified polyamide curing agent, and heat to 70°C while stirring. After the anhydrous citric acid is completely dissolved, cool to room temperature, then add vegetable oleic acid and 2-ethyl-4-methylimidazole, and disperse at high speed for 1-2 minutes to obtain component B. S3. Seal components A and B separately. When using, mix them thoroughly according to the specified ratio.

[0015] The eucommia gum-modified two-stage reactive epoxy adhesive of the present invention is first cured at 5~40℃ for 1~3 days to complete the first stage of curing, and then cured at 80~120℃ for 10~45 minutes to complete the second stage of curing.

[0016] The beneficial effects of this invention are: The Eucommia ulmoides gum-modified two-stage reactive epoxy adhesive of the present invention has two-stage reaction characteristics. First, at room temperature, the cashew phenol-modified phenolic amine curing agent and the modified polyamide curing agent can undergo a primary curing reaction with component A to achieve surface drying. Second, at high temperature, due to the softening caused by heat, it exhibits a flowable state. At the same time, under the action of 2-ethyl-4-methylimidazole, the carboxyl groups of vegetable oleic acid and anhydrous citric acid can undergo a secondary curing reaction with component A to achieve final curing.

[0017] The eucommia gum-modified two-stage reactive epoxy adhesive of the present invention uses epoxidized eucommia gum rich in cis-butadiene rubber segments, and vegetable oleic acid containing a large number of long-chain aliphatic hydrocarbon segments, monofunctional reactive diluent, bifunctional reactive diluent, cashew phenol-modified phenolic amine curing agent, etc., combined with moderate crosslinking of two-stage curing, to synergistically give the epoxy adhesive excellent flexibility.

[0018] The second-stage reactive epoxy adhesive modified with Eucommia ulmoides gum of the present invention uses epoxidized Eucommia ulmoides gum similar to cis-butadiene rubber, and monofunctional reactive diluents, bifunctional reactive diluents, vegetable oleic acid, etc. containing a large number of long-chain aliphatic hydrocarbon segments. When paving high-temperature asphalt mixtures, the heated epoxy adhesive exhibits a fluid dynamic. The large number of long-chain aliphatic hydrocarbons have strong compatibility with non-polar asphalt and can penetrate and entangle with each other at the interface, thereby improving the bonding strength between the epoxy adhesive and the asphalt mixture.

[0019] The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum of the present invention uses bio-based raw materials such as Eucommia ulmoides gum, vegetable oleic acid, cashew phenol, and citric acid directly or indirectly, which reduces the consumption of petroleum-based raw materials and improves the green environmental protection and renewability of epoxy adhesives.

[0020] The Eucommia ulmoides-modified epoxy adhesive provided by this invention achieves synergistic effects among its components through optimized selection and scientific formulation, thereby possessing advantages such as second-order reaction characteristics, high flexibility, high bonding strength, and green environmental protection and recyclability. It is especially suitable for waterproof bonding between steel or concrete base surfaces and asphalt pavement layers in roads, bridges, etc. Detailed Implementation

[0021] To make the present invention easier to understand, specific embodiments are described below to further illustrate the invention. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical terms used below have the same meaning as understood by those skilled in the art; unless otherwise specified, the raw materials and reagents involved herein can be purchased commercially or obtained by known methods.

[0022] The following detailed explanation is further illustrated with specific examples.

[0023] Example 1

[0024] A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 20 parts; 20 parts of modified polyamide curing agent TY5324; Palmitic acid 57.5 parts; 1 part anhydrous citric acid; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75; The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g, and its preparation process includes the following steps: S1. Add the eucommia gum to a mixed solvent of toluene and petroleum ether in a volume ratio of 1:1, and heat to 70°C with stirring until completely dissolved; S2. Introduce nitrogen gas and slowly add a mixed solution of tetraalkylammonium molybdate (0.2% of the mass of Eucommia ulmoides gum) and tert-butyl hydroperoxide (15% of the mass of Eucommia ulmoides gum) until the epoxy value reaches the required level, then stop the reaction. S3. After cooling to room temperature, add sodium sulfite aqueous solution and stir for 30 minutes. Then add ethanol and continue stirring for 10 minutes. Filter to obtain precipitate, wash with ethanol, and dry to obtain epoxidized Eucommia gum.

[0025] A method for preparing a second-order reactive epoxy adhesive modified with Eucommia ulmoides gum includes the following steps: S1. Add epoxidized Eucommia gum to C12-13-decyl glycidyl ether and neopentyl glycol diglycidyl ether, and heat to 70°C while stirring. After the epoxidized Eucommia gum is completely dissolved, add E51 epoxy resin, Anjeka-5680A, and KH560, and disperse at high speed for 1-2 min. Then add AEROSIL A200 and disperse at high speed for 3-5 min to obtain component A. S2. Add anhydrous citric acid to XY-3209 and TY5324, heat to 70°C while stirring, and after the anhydrous citric acid is completely dissolved, cool to room temperature, then add palmitic acid and 2-ethyl-4-methylimidazole, and disperse at high speed for 1 to 2 minutes to obtain component B. S3. Seal components A and B separately. When using, mix them evenly according to the ratio. First, cure at 23℃ for 1 day to complete the first stage of curing, and then cure at 100℃ for 30 minutes to complete the second stage of curing.

[0026] Example 2

[0027] A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 22 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 27 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 22 parts; 22 parts of modified polyamide curing agent TY5324; 53 parts of ricinoleic acid; 1.2 parts anhydrous citric acid; 1.8 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75; The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0028] Example 3

[0029] A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: Epoxidized Eucommia ulmoides gum, 30 parts; 25 parts of liquid bisphenol A type epoxy resin E51; 22 parts of C12-13-alkyl glycidyl ether; 22 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 25 parts; 18 parts of modified polyamide curing agent TY5324; Palmitic acid 54 parts; 1.5 parts anhydrous citric acid; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75.

[0030] The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0031] Comparative Example 1 A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 20 parts; 20 parts of modified polyamide curing agent TY5324; Palmitic acid 57.5 parts; 1 part anhydrous citric acid; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75.

[0032] The preparation method of the second-order reactive epoxy adhesive modified with Eucommia ulmoides gum is the same as in Example 1.

[0033] Comparative Example 2 A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: 20 parts of modified phenolic amine curing agent SF-PAA-4525S; 20 parts of modified polyamide curing agent TY5324; Palmitic acid 57.5 parts; 1 part anhydrous citric acid; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75.

[0034] The modified phenolic amine curing agent SF-PAA-4525S can be purchased from Changzhou Shanfeng Chemical Co., Ltd.; the epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0035] Comparative Example 3 A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 48.5 parts; 49 parts of modified polyamide curing agent TY5324; 1 part anhydrous citric acid; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:65.

[0036] The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0037] Comparative Example 4 A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 20 parts; 20 parts of modified polyamide curing agent TY5324; Palmitic acid 58.5 parts; 1.5 parts of 2-ethyl-4-methylimidazole; The mass ratio of component A to component B is 100:75.

[0038] The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0039] Comparative Example 5 A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, comprising component A and component B: Component A comprises the following components in parts by weight: 25 parts of epoxidized Eucommia ulmoides gum; 25 parts of liquid bisphenol A type epoxy resin E51; 25 parts of C12-13-alkyl glycidyl ether; 24 parts of neopentyl glycol diglycidyl ether; KH560 0.7 copies; AEROSIL A200 0.2 copies; Anjeka-5680A 0.1 copy; Component B comprises the following components in parts by weight: Cashew phenol-modified phenolic amine curing agent XY-3209, 20 parts; 20 parts of modified polyamide curing agent TY5324; Palmitic acid 59 parts; 1 part anhydrous citric acid; The mass ratio of component A to component B is 100:75.

[0040] The epoxy value of the epoxidized Eucommia ulmoides gum is 0.93 mmol / g; the preparation methods of the epoxidized Eucommia ulmoides gum and the Eucommia ulmoides gum-modified second-order reactive epoxy adhesive are the same as in Example 1.

[0041] The second-order reaction characteristic test of the epoxy adhesives in Examples 1-3 and Comparative Examples 1-5 included three process tests. Passing all three process tests indicates the presence of second-order reaction characteristics. Specifically: after curing at 23℃ for 1 day, it is considered primary curing and should be surface dry; after primary curing, heating to 150℃ should result in a viscous consistency with slight flow; after curing at 100℃ for 30 minutes, it is considered secondary curing and should be non-flowable after heating to 150℃. The tensile strength, elongation at break, bond strength (with steel plate, 25℃), bond strength (with C45 concrete, 25℃), bond strength (with epoxy asphalt mixture, 25℃), and bond strength (with modified asphalt mixture, 25℃) of the epoxy adhesives in Examples 1-3 and Comparative Examples 1-5 were all tested according to the "Technical Specification for Design and Construction of Highway Steel Bridge Deck Pavement" JTG / T3364-02-2019. The bio-based content of the epoxy adhesives in Examples 1-3 and Comparative Examples 1-5 is the percentage of the total mass of bio-based raw materials. The relevant results are shown in Table 1. Table 1 Performance test results of epoxy adhesives in Examples 1-3 and Comparative Examples 1-5

[0042] As can be seen from Examples 1-3 in Table 1, the epoxy adhesive of the present invention has the characteristics of second-order reaction, high flexibility, high bonding strength, green environmental protection and renewable (high bio-based content), and is very suitable for waterproof bonding between steel and concrete base surfaces and asphalt pavement layers in roads, bridges and other projects.

[0043] As can be seen from Examples 1-3 and Comparative Example 1, Comparative Example 1 used unepoxidized Eucommia ulmoides gum, resulting in poor tensile strength, low bond strength (with steel plate, 25°C), and low bond strength (with C45 concrete, 25°C) of the epoxy adhesive prepared in Comparative Example 1. Consequently, it was unsuitable for waterproof bonding between steel and concrete substrates and asphalt pavement layers in roads, bridges, etc. Therefore, it can be demonstrated that epoxidized Eucommia ulmoides gum is crucial to the flexibility and bond strength of epoxy adhesives.

[0044] As can be seen from Examples 1-3 and Comparative Example 2, Comparative Example 2 uses a cashew nut shell modified phenolic amine curing agent, resulting in low elongation at break, low bond strength (with epoxy asphalt mixture, 25°C), and low bond strength (with modified asphalt mixture, 25°C) of the epoxy adhesive prepared in Comparative Example 2. Therefore, it is unsuitable for waterproof bonding between steel and concrete substrates and asphalt pavement layers in roads, bridges, etc. Simultaneously, the bio-based content is also reduced, resulting in poor environmental friendliness and renewability. Therefore, it can be proven that a cashew nut shell modified phenolic amine curing agent is a necessary condition for ensuring the flexibility, bond strength, and renewability of epoxy adhesives.

[0045] As can be seen from Examples 1-3 and Comparative Example 3, Comparative Example 3 did not introduce vegetable oleic acid, resulting in the epoxy adhesive prepared in Comparative Example 3 failing to meet the requirements for second-order reaction characteristics after initial curing and heating, as well as exhibiting low elongation at break, low bond strength (with epoxy asphalt mixture, 25℃), and low bond strength (with modified asphalt mixture, 25℃). Consequently, it is unsuitable for waterproof bonding between steel and concrete substrates and asphalt pavement layers in roads, bridges, etc. Simultaneously, the bio-based content is also reduced, leading to poor environmental friendliness and renewability. Therefore, it can be demonstrated that vegetable oleic acid is a necessary condition for ensuring the second-order reaction characteristics, flexibility, bond strength, and renewability of epoxy adhesives.

[0046] As can be seen from Examples 1-3 and Comparative Example 4, Comparative Example 4 did not introduce anhydrous citric acid, resulting in poor tensile strength, low bond strength (with steel plate, 25°C), and low bond strength (with C45 concrete, 25°C) of the epoxy adhesive prepared in Comparative Example 4. Consequently, it was unsuitable for waterproof bonding between steel and concrete substrates and asphalt pavement layers in roads, bridges, etc. Therefore, it can be proven that anhydrous citric acid is a necessary condition to ensure the flexibility and bond strength of epoxy adhesives.

[0047] As can be seen from Examples 1-3 and Comparative Example 5, Comparative Example 5 did not introduce 2-ethyl-4-methylimidazole, resulting in the epoxy adhesive prepared in Comparative Example 5 failing to meet the requirements for the second-order reaction characteristics after secondary curing and heating. Furthermore, it exhibited low tensile strength, low elongation at break, low bond strength (with steel plate, 25°C), low bond strength (with C45 concrete, 25°C), low bond strength (with epoxy asphalt mixture, 25°C), and low bond strength (with modified asphalt mixture, 25°C). Consequently, it was unsuitable for waterproof bonding between steel and concrete substrates and asphalt pavement layers in roads, bridges, etc. Therefore, it can be demonstrated that 2-ethyl-4-methylimidazole is a necessary condition for ensuring the second-order reaction characteristics, flexibility, and bond strength of epoxy adhesives.

[0048] In order to achieve the best synergistic effect and optimal performance, the components of the two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum of this invention must reach a scientific balance.

[0049] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum, characterized in that, Includes component A and component B; Component A comprises the following components in parts by weight: Epoxidized Eucommia ulmoides gum 20-45 parts; 20-50 parts of liquid epoxy resin; 10-40 parts of monofunctional active diluent; 10-40 parts of bifunctional active diluent; 0.5 to 2 parts of coupling agent; Thixotropic agent 0.1~1 part; Defoamer 0.05~0.5 parts; Component B comprises the following components in parts by weight: 10-30 parts of cashew phenol-modified phenolic amine curing agent; 10-30 parts of modified polyamide curing agent; 40-80 parts of vegetable oleic acid; 0.5 to 3 parts of anhydrous citric acid; 0.5 to 4 parts of 2-ethyl-4-methylimidazole; The epoxy value of the epoxidized Eucommia ulmoides gum is 0.7~2.1 mmol / g, and its preparation process includes the following steps: S1. Add Eucommia gum to the mixed solvent and heat to 70°C with stirring until completely dissolved; S2. Introduce nitrogen gas and slowly add a mixed solution of tetraalkylammonium molybdate and tert-butyl hydrogen peroxide dropwise until the epoxy value reaches the required level, then stop the reaction. S3. After cooling to room temperature, add sodium sulfite aqueous solution and stir for 30 minutes. Then add ethanol and continue stirring for 10 minutes. After filtration, washing and drying, epoxidized Eucommia gum is obtained. The mass ratio of component A to component B is 100:60~100.

2. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, In step S1, the Eucommia gum is Eucommia gum with a natural Eucommia gum content of ≥98%; The mixed solvent is a mixture of toluene and petroleum ether in a volume ratio of 1:

1.

3. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, In step S2, the amount of tetraalkylammonium molybdate used is 0.05~0.50% of the mass of Eucommia ulmoides gum; The amount of tert-butyl hydroperoxide used is 5-25% of the mass of Eucommia ulmoides gum.

4. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, The liquid epoxy resin is a liquid bisphenol A type epoxy resin with an epoxy value of 4.2~5.3 mmol / g; The monofunctional active diluent is one of C8-decyl glycidyl ether, C12-tetradecyl glycidyl ether, C12-twelfthyl glycidyl ether, or C12-decyl glycidyl ether. The bifunctional active diluent is one of neopentyl glycol diglycidyl ether and 1,6-hexanediol diglycidyl ether.

5. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, The coupling agent is KH560; The thixotropic agent is Evonik AEROSIL A200 silica. The defoamer is Anjeka-5680A from Ezhou Anjikang Technology Co., Ltd.

6. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, The plant oleic acid is one of myristic acid, palmitic acid, palmitoleic acid, tung oil acid, and ricinoleic acid.

7. The two-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to claim 1, characterized in that, The cashew phenol-modified phenolic amine curing agent is Shanghai Xuanyuan New Material Technology Co., Ltd.'s cashew phenol-modified phenolic amine curing agent XY-3209. The modified polyamide curing agent is TY5324 modified polyamide curing agent from Jining Fangde Chemical Co., Ltd.

8. A method for preparing the second-stage reactive epoxy adhesive modified with Eucommia ulmoides gum according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Add epoxidized Eucommia ulmoides gum to monofunctional reactive diluent and difunctional reactive diluent, and heat to 70°C while stirring. After the epoxidized Eucommia ulmoides gum is completely dissolved, add liquid epoxy resin, defoamer and coupling agent, and disperse at high speed for 1-2 minutes. Then add thixotropic agent and disperse at high speed for 3-5 minutes to obtain component A. S2. Add anhydrous citric acid to cashew phenol-modified phenolic amine curing agent and modified polyamide curing agent, and heat to 70°C while stirring. After the anhydrous citric acid is completely dissolved, cool to room temperature, then add vegetable oleic acid and 2-ethyl-4-methylimidazole, and disperse at high speed for 1-2 minutes to obtain component B. S3. Seal components A and B separately. When using, mix them thoroughly according to the specified ratio.

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