Epoxy resin and preparation method thereof

Abstract

The invention relates to the technical field of epoxy resin, and particularly discloses epoxy resin and a preparation method thereof.The epoxy resin is prepared from, by weight, 95-133 parts of functional epoxy resin component, 16-32 parts of curing enhancer, 3.6-7.4 parts of curing accelerator, 0.9-1.3 parts of photoinitiator and 420-560 parts of solvent; the functional epoxy resin component and the curing enhancer are added, and the functional epoxy resin component comprises a benzene ring, a flexible long-chain alkane structure, a carbon-nitrogen double bond, a flexible long-chain alkane structure, an ester group and an epoxy group. The functional epoxy resin component can be entangled with the molecular chain structure of the curing enhancer to form an intertwined molecular interpenetrating network structure and has reversible dynamic chemical bonds, and meanwhile, the curing enhancer has sulfydryl and amino which can generate chemical crosslinking with the functional epoxy resin component and form hydrogen-bond interaction with the functional epoxy resin component. The strength, the self-repairing property and the degradability of the epoxy resin are improved.

Description

Technical Field

[0001] The present application relates to the technical field of epoxy resins, and more specifically, to an epoxy resin and a preparation method thereof. Background Art

[0002] Epoxy resin is a thermosetting polymer with two or more epoxy groups. It is widely used in packaging materials due to its small curing shrinkage and thermal expansion coefficient, good dimensional stability, good processability, low cost and excellent comprehensive performance.

[0003] However, since epoxy resin forms an insoluble and infusible three-dimensional network structure after being cured by a curing agent, it degrades slowly in the natural environment after use and becomes solid waste. At the same time, epoxy resin is inevitably exposed to external stimuli such as heat, mechanical, chemical and ultraviolet radiation during use, which can cause local damage or microcracks inside the epoxy resin. The expansion of microcracks eventually leads to the rupture of the epoxy resin, greatly reducing its use value and safety.

[0004] Therefore, in order to make better use of epoxy resin, it is urgent to develop an epoxy resin with high strength, biodegradability and self-healing properties. Summary of the invention In order to solve the problems mentioned in the above background technology, the present application provides an epoxy resin and a preparation method thereof.

[0005] An epoxy resin comprises the following raw materials in parts by weight: 95-133 parts of a functionalized epoxy resin component, 16-32 parts of a curing enhancer, 3.6-7.4 parts of a curing accelerator and 0.9-1.3 parts of a photoinitiator; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and photoinitiator are stirred evenly, heated to 42-46°C, irradiated with ultraviolet light for 14-18 minutes while stirring, and then a curing accelerator is added, heated to 54-62°C, stirred for 32-46 minutes, and rotary evaporated to obtain epoxy resin.

[0006] The functionalized epoxy resin component, the curing enhancer and the photoinitiator are stirred uniformly, specifically, the functionalized epoxy resin component, the curing enhancer and the photoinitiator are added into 420-560 parts of the solvent, and stirred for 22-30 minutes.

[0007] Preferably, the solvent is at least one of anhydrous methanol, ethyl acetate and tetrahydrofuran.

[0008] Preferably, the curing accelerator is at least one of 1-benzylbenzene-2-ethylimidazole, 2-ethyl-4-methylimidazole and 1-aminoethyl-2-methylimidazole.

[0009] Preferably, the photoinitiator is 1-hydroxycyclohexyl phenyl ketone.

[0010] Preferably, the functionalized epoxy resin component is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring evenly, then adding glacial acetic acid, heating to reflux, stirring to react for 5-7h, rotary evaporation, washing, and drying to obtain a Schiff base monomer, wherein the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is (4-6): (2.6-3.4): (42-56): (0.06-0.1). In the above reaction process, anhydrous ethanol is used as solvent and glacial acetic acid is used as catalyst, and the aldehyde group on 2,4-dihydroxybenzaldehyde and the amino group on ethanolamine undergo Schiff condensation reaction to obtain a Schiff base monomer; The equation for this reaction is shown below: ; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid to anhydrous ethanol, heating to 35-45°C, stirring evenly, then heating to reflux, continuing stirring to react for 2-4h, rotary evaporation, washing, and drying to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is (4.2-5.6): (0.12-0.24): (3.8-5.0): (54-66). In the above reaction process, using anhydrous ethanol as solvent, the active hydroxyl group on the Schiff base monomer undergoes esterification reaction with the carboxyl group on the p-hydroxycinnamic acid to obtain a modified monomer. The reaction equation is as follows: ; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, raise the temperature to 86-92°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, and control the dripping to be completed within 10 minutes. After the dripping is completed, stir and react for 3.6-4.2 hours. After the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, and control the dripping to be completed within 30 minutes. Continue stirring for 0.6-0.8 hours, add alkali solution dropwise again, and control the dripping to be completed within 30 minutes. Continue stirring for 1.8-2.2 hours, filter under reduced pressure, wash, and dry to obtain a functionalized epoxy resin component. The reaction equation is as follows:

[0011] The mass ratio of the modified monomer, methyl isobutyl ketone, tetrabutyl ammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution is (5.4-6.6): (56-64): (0.04-0.06): (6-10): (2.4-3.0): (22-26). The alkali solution added for the first time is a sodium hydroxide aqueous solution with a mass fraction of 40-50%, and the alkali solution added for the second time is a sodium hydroxide aqueous solution with a mass fraction of 32-36%. The masses of the alkali solutions added twice are the same. In the above reaction process, methyl isobutyl ketone is used as a solvent, tetrabutyl ammonium bromide is used as a catalyst, and toluene is used as a dehydrating agent. The phenolic hydroxyl group on the modified monomer first undergoes an addition reaction with epichlorohydrin, and then under the action of the base, the hydrogen chloride is removed by ring closing to obtain a functionalized epoxy resin component.

[0012] Preferably, the curing enhancer is prepared by the following steps: Step B1, add L-cysteine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid to anhydrous DMF, heat to 35-45°C, stir evenly, then heat to 72-84°C, continue stirring to react for 3.4-4.6h, rotary evaporate, wash, and dry to obtain a disulfide monomer, wherein the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is (3.6-4.4): (0.03-0.05) : (2.1-2.7): (50-60), in the above reaction process, with anhydrous DMF as solvent, the active amino group on L-cysteine ​​and the carboxyl group on 3,3'-dithiodipropionic acid undergo esterification reaction to obtain a modified monomer. During the reaction, the amount of L-cysteine ​​is controlled to be slightly higher than two times the equivalent of 3,3'-dithiodipropionic acid, so that the carboxyl group on 3,3'-dithiodipropionic acid can be fully consumed. The reaction equation is as follows: ; Step B2, add diethylenetriamine and disulfide monomer to anhydrous DMF, stir evenly, and drop a mixture of N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF while stirring. After dropping, heat to 72-78°C, stir and react for 3-5 hours. After the reaction is completed, filter, wash and dry to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixture a is (6-8): (20-26): (80-90) : (30-40), in the mixed solution a, the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF is (5.6-7.2): (3.6-4.6): (23-27), in the above reaction process, anhydrous DMF is used as solvent, N, N-dicyclohexylcarbodiimide is used as dehydrating agent, 4-dimethylaminopyridine is used as acylating agent, diethylenetriamine and disulfide monomer undergo amidation reaction to obtain a curing enhancer, and the reaction equation is shown below: .

[0013] Compared with the prior art, the present invention has the following beneficial effects: (1) In order to improve the strength of epoxy resin and prepare epoxy resin materials with self-healing properties, the present invention starts from two aspects. First, a functionalized epoxy resin component is added to the raw material. The functionalized epoxy resin component contains a benzene ring, a flexible long-chain alkane structure, a carbon-nitrogen double bond, a flexible long-chain alkane structure, an ester group and an epoxy group. Based on the presence of the benzene ring and the flexible long-chain alkane structure, the toughness and impact resistance of the epoxy resin are improved. In addition, the flexible long-chain alkane structure can be entangled with the molecular chain structure of the curing enhancer to form a mutually entangled molecular interpenetrating network structure, so that it has good compatibility with the curing enhancer, thereby improving the toughness of the epoxy resin. The carbon-nitrogen double bond has Reversible dynamic chemical bonds, and at the same time, the ester group can form multiple hydrogen bonds with the ester group and amino group in the curing enhancer. Through the above joint action, micron-scale cracks can be repaired and the self-healing properties of epoxy resin can be improved. The presence of epoxy groups can chemically bond with the amino groups in the curing enhancer to further improve the toughness of epoxy resin; second, the curing enhancer is added. On the one hand, the curing enhancer contains thiol groups that can chemically cross-link with functionalized epoxy resin components. On the other hand, the surface of the modified reinforcer is grafted with disulfide bonds with low bond energy and dynamic effects. Introducing it into the epoxy resin can synergize with the functionalized epoxy resin components to jointly improve the strength and self-healing properties of the epoxy resin.

[0014] (2) The epoxy resin prepared in the present application contains degradable structural units such as ester groups, disulfide bonds, and Schiff base structures, which can be degraded under mild conditions to achieve resource recycling and reuse, thus meeting the needs of sustainable social development. DETAILED DESCRIPTION

[0015] In order to make the implementation methods of the present application easier to understand, the present application will be described in detail below in conjunction with specific examples. These examples are only for illustration and are not limited to the scope of application of the present application.

[0016] The present application is further described in detail below in conjunction with embodiments and comparative examples.

[0017] Preparation Examples 1-3 and Comparative Preparation Examples 1-2 provide methods for preparing functionalized epoxy resin components.

[0018] Preparation Example 1 This preparation example provides a functionalized epoxy resin component, which is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring at a speed of 500 rpm for 18 minutes until uniform, then adding glacial acetic acid, heating to reflux, maintaining the speed unchanged, continuing to stir and react for 5 hours, controlling the rotary evaporation temperature to 64°C, rotary evaporating to remove anhydrous ethanol, washing with deionized water for 3 times, and drying at 55°C to constant weight to obtain a Schiff base monomer, wherein the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is 4:2.6:42:0.06; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid to anhydrous ethanol, heating to 35°C, stirring at a rotation speed of 550 rpm for 24 minutes until uniform, then heating to reflux, continuing to stir and react for 2 hours, controlling the rotary evaporation temperature to 66°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water for 3 times, and drying at 62°C to constant weight to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is 4.2:0.12:3.8:54; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, control the ultrasonic frequency to 35kHz, the ultrasonic power to 550w, the ultrasonic for 24min, control the speed to 600rpm, raise the temperature to 86°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, control the dripping to be completed within 10min, after the dripping is completed, stir and react for 3.6h, after the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, control the dripping to be completed within 30min, continue stirring for 0.6h, add alkali solution dropwise again, control the dripping to be completed within 30min After completion, stirring was continued for 1.8 hours, and the mixture was filtered under reduced pressure. The mixture was washed three times with anhydrous ethanol and deionized water in sequence, and dried at 68°C to constant weight to obtain a functionalized epoxy resin component, wherein the mass ratio of the modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution was 5.4:56:0.04:6:2.4:22, the alkali solution added for the first time was a sodium hydroxide aqueous solution with a mass fraction of 40%, and the alkali solution added for the second time was a sodium hydroxide aqueous solution with a mass fraction of 32%, and the masses of the alkali solution added twice were the same.

[0019] Preparation Example 2 This preparation example provides a functionalized epoxy resin component, which is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring at a rotation speed of 600 rpm for 22 minutes until uniform, then adding glacial acetic acid, heating to reflux, stirring and reacting for 6 hours, controlling the rotary evaporation temperature to 68° C., rotary evaporation to remove anhydrous ethanol, washing with deionized water for 4 times, and drying at 60° C. to constant weight to obtain a Schiff base monomer, wherein the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is 5:3.0:49:0.08; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid to anhydrous ethanol, heating to 40°C, stirring at a rotation speed of 580 rpm for 26 minutes until uniform, then heating to reflux, continuing to stir and react for 3 hours, controlling the rotary evaporation temperature to 72°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water 4 times, and drying at 64°C to constant weight to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is 4.9:0.18:4.4:60; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, control the ultrasonic frequency to 40kHz, the ultrasonic power to 600w, the ultrasonic for 26min, control the speed to 650rpm, and heat to 89°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, and control the dripping to be completed within 10min. After the dripping is completed, stir and react for 3.9h. After the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, and control the dripping to be completed within 30min. Continue stirring for 0.7h, add alkali solution dropwise again, and control the dripping to be completed within 30min. After completion, stirring was continued for 2.0 h, filtered under reduced pressure, washed with anhydrous ethanol and deionized water for 4 times in sequence, and dried at 72°C to constant weight to obtain a functionalized epoxy resin component, wherein the mass ratio of modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution was 6.0:60:0.05:8:2.7:24, the alkali solution added for the first time was a sodium hydroxide aqueous solution with a mass fraction of 45%, and the alkali solution added for the second time was a sodium hydroxide aqueous solution with a mass fraction of 34%, and the masses of the alkali solutions added twice were the same.

[0020] Preparation Example 3 This preparation example provides a functionalized epoxy resin component, which is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring at a rotation speed of 700 rpm for 26 minutes until uniform, then adding glacial acetic acid, heating to reflux, stirring and reacting for 7 hours, controlling the rotary evaporation temperature to 74°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water for 5 times, and drying at 65°C to constant weight to obtain a Schiff base monomer, wherein the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is 6:3.4:56:0.1; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid to anhydrous ethanol, heating to 45°C, stirring at a rotation speed of 610 rpm for 30 minutes until uniform, then heating to reflux, continuing to stir and react for 4 hours, controlling the rotary evaporation temperature to 78°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water 5 times, and drying at 66°C to constant weight to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is 5.6:0.24:5.0:66; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, control the ultrasonic frequency to 46kHz, the ultrasonic power to 650w, ultrasonic for 28min, control the speed to 700rpm, stir while heating to 92°C, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, control the dripping to be completed within 10min, stir and react for 4.2h, after the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, control the dripping to be completed within 30min, continue stirring for 0.8h, add alkali solution dropwise again, control the dripping to be completed within 30min , continue stirring for 2.2h, filter under reduced pressure, wash with anhydrous ethanol and deionized water for 5 times in sequence, and dry at 76°C to constant weight to obtain a functionalized epoxy resin component, wherein the mass ratio of modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution is 6.6:64:0.06:10:3.0:26, the alkali solution added for the first time is a sodium hydroxide aqueous solution with a mass fraction of 50%, and the alkali solution added for the second time is a sodium hydroxide aqueous solution with a mass fraction of 36%, and the masses of the alkali solutions added twice are the same.

[0021] Comparative Preparation Example 1 This comparative preparation example provides a functionalized epoxy resin component, which is prepared by the following steps: Step A1, adding hydroxycitronellal and ethanolamine to anhydrous ethanol, stirring at a rotation speed of 500 rpm for 18 minutes until uniform, then adding glacial acetic acid, heating to reflux, maintaining the rotation speed unchanged, continuing to stir and react for 5 hours, controlling the rotary evaporation temperature to 64°C, rotary evaporating until the anhydrous ethanol is removed, washing with deionized water for 3 times, and drying at 55°C to constant weight to obtain a Schiff base monomer, wherein the mass ratio of hydroxycitronellal, ethanolamine, anhydrous ethanol and glacial acetic acid is 4:2.6:42:0.06; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid to anhydrous ethanol, heating to 35°C, stirring at a rotation speed of 550 rpm for 24 minutes until uniform, then heating to reflux, continuing to stir and react for 2 hours, controlling the rotary evaporation temperature to 66°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water for 3 times, and drying at 62°C to constant weight to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is 4.2:0.12:3.8:54; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, control the ultrasonic frequency to 35kHz, the ultrasonic power to 550w, the ultrasonic for 24min, control the speed to 600rpm, raise the temperature to 86°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, control the dripping to be completed within 10min, after the dripping is completed, stir and react for 3.6h, after the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, control the dripping to be completed within 30min, continue stirring for 0.6h, add alkali solution dropwise again, control the dripping to be completed within 30min After completion, stirring was continued for 1.8 hours, and the mixture was filtered under reduced pressure. The mixture was washed three times with anhydrous ethanol and deionized water in sequence, and dried at 68°C to constant weight to obtain a functionalized epoxy resin component, wherein the mass ratio of the modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution was 5.4:56:0.04:6:2.4:22, the alkali solution added for the first time was a sodium hydroxide aqueous solution with a mass fraction of 40%, and the alkali solution added for the second time was a sodium hydroxide aqueous solution with a mass fraction of 32%, and the masses of the alkali solution added twice were the same.

[0022] Comparative Preparation Example 2 This comparative preparation example provides a functionalized epoxy resin component, which is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring at a speed of 500 rpm for 18 minutes until uniform, then adding glacial acetic acid, heating to reflux, maintaining the speed unchanged, continuing to stir and react for 5 hours, controlling the rotary evaporation temperature to 64°C, rotary evaporating to remove anhydrous ethanol, washing with deionized water for 3 times, and drying at 55°C to constant weight to obtain a Schiff base monomer, wherein the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is 4:2.6:42:0.06; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and 2,2-dimethyl-3-hydroxypropionic acid to anhydrous ethanol, heating to 35°C, stirring at a rotation speed of 550 rpm for 24 minutes until uniform, then heating to reflux, continuing to stir and react for 2 hours, controlling the rotary evaporation temperature to 66°C, rotary evaporation to remove anhydrous ethanol, washing with deionized water for 3 times, and drying at 62°C to constant weight to obtain a modified monomer, wherein the mass ratio of Schiff base monomer, p-toluenesulfonic acid, 2,2-dimethyl-3-hydroxypropionic acid and anhydrous ethanol is 4.2:0.12:3.8:54; Step A3, ultrasonically disperse the modified monomer in methyl isobutyl ketone, control the ultrasonic frequency to 35kHz, the ultrasonic power to 550w, the ultrasonic for 24min, control the speed to 600rpm, raise the temperature to 86°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, control the dripping to be completed within 10min, after the dripping is completed, stir and react for 3.6h, after the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, control the dripping to be completed within 30min, continue stirring for 0.6h, add alkali solution dropwise again, control the dripping to be completed within 30min After completion, stirring was continued for 1.8 hours, and the mixture was filtered under reduced pressure. The mixture was washed three times with anhydrous ethanol and deionized water in sequence, and dried at 68°C to constant weight to obtain a functionalized epoxy resin component, wherein the mass ratio of the modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution was 5.4:56:0.04:6:2.4:22, the alkali solution added for the first time was a sodium hydroxide aqueous solution with a mass fraction of 40%, and the alkali solution added for the second time was a sodium hydroxide aqueous solution with a mass fraction of 32%, and the masses of the alkali solution added twice were the same.

[0023] Preparation Examples 4-6 and Comparative Preparation Examples 3-4 provide a curing enhancer.

[0024] Preparation Example 4 This preparation example provides a curing enhancer, which is prepared by the following steps: Step B1, L-cysteine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid are added to anhydrous DMF, the temperature is raised to 35°C, and the mixture is stirred at a speed of 620 rpm for 20 min until uniform, and then the temperature is raised to 72°C, the speed is maintained unchanged, and the stirring reaction is continued for 3.4 hours, and the rotary evaporation temperature is controlled to be 81°C, and the anhydrous DMF is removed by rotary evaporation, and then the mixture is washed with anhydrous ethanol and deionized water for 3 times in sequence, and dried at 66°C to constant weight to obtain a disulfide monomer, wherein the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is 3.6:0.03:2.1:50; Step B2, add diethylenetriamine and disulfide monomer to anhydrous DMF, stir at a speed of 720rpm for 18min until uniform, and add N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and a mixed solution a of anhydrous DMF while stirring. After the addition, heat to 72°C, maintain the speed unchanged, and continue stirring to react for 3h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and deionized water three times in sequence, and dry at 70°C to constant weight to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is 6:20:80:30, and the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF in the mixed solution a is 5.6:3.6:23.

[0025] Preparation Example 5 This preparation example provides a curing enhancer, which is prepared by the following steps: Step B1, L-cysteine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid are added to anhydrous DMF, the temperature is raised to 40°C, and the mixture is stirred at a speed of 660 rpm for 24 min until uniform, the mixture is stirred uniformly, the temperature is raised to 78°C, the speed is maintained unchanged, and the stirring reaction is continued for 4.0 h. The rotary evaporation temperature is controlled to 85°C, and the anhydrous DMF is removed by rotary evaporation. The mixture is then washed with anhydrous ethanol and deionized water for 4 times in sequence, and dried at 70°C to constant weight to obtain a disulfide monomer, wherein the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is 4.0:0.04:2.4:55; Step B2, add diethylenetriamine and disulfide monomer to anhydrous DMF, stir at a speed of 760rpm for 22min until uniform, and add N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and a mixed solution a of anhydrous DMF while stirring. After the addition is completed, the temperature is raised to 75°C, the speed is maintained unchanged, and the stirring reaction is continued for 4h. After the reaction is completed, the filter is filtered, and the filter cake is washed with anhydrous ethanol and deionized water for 4 times in sequence, and dried at 74°C to constant weight to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is 7:23:85:35, and the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF in the mixed solution a is 6.4:4.1:25.

[0026] Preparation Example 6 This preparation example provides a curing enhancer, which is prepared by the following steps: Step B1, L-cysteine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid are added to anhydrous DMF, the temperature is raised to 45°C, and the mixture is stirred at a speed of 700 rpm for 28 minutes until uniform, and then the temperature is raised to 84°C, the speed is maintained unchanged, and the stirring reaction is continued for 4.6 hours, and the rotary evaporation temperature is controlled to 89°C, and the anhydrous DMF is removed by rotary evaporation, and then the mixture is washed with anhydrous ethanol and deionized water for 5 times in sequence, and dried at 74°C to constant weight to obtain a disulfide monomer, wherein the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is 4.4:0.05:2.7:60; Step B2, diethylenetriamine and disulfide monomer are added to anhydrous DMF, stirred at a speed of 800 rpm for 26 minutes until uniform, and a mixed solution a of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF is added while stirring. After the addition is completed, the temperature is raised to 78°C, the speed is maintained unchanged, and the stirring reaction is continued for 5 hours. After the reaction is completed, the filter is filtered, and the filter cake is washed with anhydrous ethanol and deionized water for 5 times in sequence, and dried at 78°C to constant weight to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is 8:26:90:40, and the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF in the mixed solution a is 7.2:4.6:27.

[0027] Comparative Preparation Example 3 This comparative preparation example provides a curing enhancer, which is prepared by the following steps: Step B1, add L-cysteine, trifluoromethanesulfonic acid and 3,3'-thiodipropionic acid to anhydrous DMF, heat to 35°C, stir at a speed of 620rpm for 20min until uniform, then heat to 72°C, maintain the speed unchanged, continue stirring to react for 3.4h, control the rotary evaporation temperature to 81°C, rotary evaporation to remove anhydrous DMF, then wash with anhydrous ethanol and deionized water for 3 times in sequence, and dry at 66°C to constant weight to obtain a disulfide monomer, wherein the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-thiodipropionic acid and anhydrous DMF is 3.6:0.03:2.1:50; Step B2, add diethylenetriamine and disulfide monomer to anhydrous DMF, stir at a speed of 720rpm for 18min until uniform, and add N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and a mixed solution a of anhydrous DMF while stirring. After the addition, heat to 72°C, maintain the speed unchanged, and continue stirring to react for 3h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and deionized water three times in sequence, and dry at 70°C to constant weight to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is 6:20:80:30, and the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF in the mixed solution a is 5.6:3.6:23.

[0028] Comparative Preparation Example 4 This comparative preparation example provides a curing enhancer, which is prepared by the following steps: Step B1, adding glycine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid to anhydrous DMF, heating to 35°C, stirring at a speed of 620rpm for 20min until uniform, then heating to 72°C, maintaining the speed unchanged, continuing to stir and react for 3.4h, controlling the rotary evaporation temperature to 81°C, rotary evaporation to remove anhydrous DMF, then washing with anhydrous ethanol and deionized water for 3 times in sequence, and drying at 66°C to constant weight to obtain a disulfide monomer, wherein the mass ratio of glycine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is 3.6:0.03:2.1:50; Step B2, add diethylenetriamine and disulfide monomer to anhydrous DMF, stir at a speed of 720rpm for 18min until uniform, and add N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and a mixed solution a of anhydrous DMF while stirring. After the addition, heat to 72°C, maintain the speed unchanged, and continue stirring to react for 3h. After the reaction is completed, filter, wash the filter cake with anhydrous ethanol and deionized water three times in sequence, and dry at 70°C to constant weight to obtain a curing enhancer, wherein the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is 6:20:80:30, and the mass ratio of N, N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF in the mixed solution a is 5.6:3.6:23.

[0029] Examples 1-3 and Comparative Examples 1-4 provide an epoxy resin and a preparation method thereof.

[0030] Example 1 This embodiment provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 95 parts of the functionalized epoxy resin component prepared in Preparation Example 1, 16 parts of the curing enhancer prepared in Preparation Example 4, 3.6 parts of 1-benzylbenzene-2-ethylimidazole, 0.9 parts of 1-hydroxycyclohexyl phenone, and 420 parts of anhydrous methanol; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenone were added to anhydrous methanol, stirred at 660 rpm for 22 min until uniform, heated to 42 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 14 minutes, and 1-benzylbenzene-2-ethylimidazole was added. The temperature was raised to 54°C, the rotation speed was reduced to 500 rpm, and stirring was continued for 32 minutes. The rotary evaporation temperature was controlled at 62°C, and the anhydrous methanol was removed by rotary evaporation to obtain the epoxy resin.

[0031] Example 2 This embodiment provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 114 parts of the functionalized epoxy resin component prepared in Preparation Example 2, 24 parts of the curing enhancer prepared in Preparation Example 5, 5.5 parts of 2-ethyl-4-methylimidazole, 1.1 parts of 1-hydroxycyclohexyl phenyl ketone and 490 parts of ethyl acetate; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenyl ketone were added to ethyl acetate, stirred at 700 rpm for 26 min until uniform, heated to 44 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 16 min, and 2-ethyl-4-methylimidazole was added. The temperature was raised to 58°C, the rotation speed was reduced to 520 rpm, and stirring was continued for 39 min. The rotary evaporation temperature was controlled at 74°C, and the ethyl acetate was removed by rotary evaporation to obtain epoxy resin.

[0032] Example 3 This embodiment provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 133 parts of the functionalized epoxy resin component prepared in Preparation Example 3, 32 parts of the curing enhancer prepared in Preparation Example 6, 7.4 parts of 1-aminoethyl-2-methylimidazole, 1.3 parts of 1-hydroxycyclohexyl phenyl ketone, and 560 parts of tetrahydrofuran; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenone were added to tetrahydrofuran, stirred at 740 rpm for 30 min until uniform, heated to 46 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 18 minutes, and then 1-aminoethyl-2-methylimidazole was added. The temperature was raised to 62°C, the rotation speed was reduced to 540 rpm, and stirring was continued for 46 minutes. The rotary evaporation temperature was controlled at 78°C, and the tetrahydrofuran was removed by rotary evaporation to obtain epoxy resin.

[0033] Comparative Example 1 This comparative example provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 95 parts of the functionalized epoxy resin component prepared in comparative preparation example 1, 16 parts of the curing enhancer prepared in preparation example 4, 3.6 parts of 1-benzylbenzene-2-ethylimidazole, 0.9 parts of 1-hydroxycyclohexyl phenone and 420 parts of anhydrous methanol; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenyl ketone were added to anhydrous methanol and stirred at a speed of 660 rpm for 22 min until uniform. The temperature was raised to 42 °C and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 14 minutes, and 1-benzylbenzene-2-ethylimidazole was added. The temperature was raised to 54°C, the rotation speed was reduced to 500 rpm, and stirring was continued for 32 minutes. The rotary evaporation temperature was controlled at 62°C, and the anhydrous methanol was removed by rotary evaporation to obtain the epoxy resin.

[0034] Comparative Example 2 This comparative example provides an epoxy resin, which includes the following raw materials in parts by weight: 95 parts of the functionalized epoxy resin component prepared in comparative preparation example 2, 16 parts of the curing enhancer prepared in preparation example 4, 3.6 parts of 1-benzylbenzene-2-ethylimidazole, 0.9 parts of 1-hydroxycyclohexyl phenyl ketone, and 420 parts of anhydrous methanol; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenone were added to anhydrous methanol, stirred at 660 rpm for 22 min until uniform, heated to 42 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 14 minutes, and 1-benzylbenzene-2-ethylimidazole was added. The temperature was raised to 54°C, the rotation speed was reduced to 500 rpm, and stirring was continued for 32 minutes. The rotary evaporation temperature was controlled at 62°C, and the anhydrous methanol was removed by rotary evaporation to obtain the epoxy resin.

[0035] Comparative Example 3 This comparative example provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 95 parts of the functionalized epoxy resin component prepared in Preparation Example 1, 16 parts of the curing enhancer prepared in Comparative Preparation Example 3, 3.6 parts of 1-benzylbenzene-2-ethylimidazole, 0.9 parts of 1-hydroxycyclohexyl phenone, and 420 parts of anhydrous methanol; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenone were added to anhydrous methanol, stirred at 660 rpm for 22 min until uniform, heated to 42 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 14 minutes, and 1-benzylbenzene-2-ethylimidazole was added. The temperature was raised to 54°C, the rotation speed was reduced to 500 rpm, and stirring was continued for 32 minutes. The rotary evaporation temperature was controlled at 62°C, and the anhydrous methanol was removed by rotary evaporation to obtain the epoxy resin.

[0036] Comparative Example 4 This comparative example provides an epoxy resin and a preparation method thereof. The epoxy resin comprises the following raw materials in parts by weight: 95 parts of the functionalized epoxy resin component prepared in Preparation Example 1, 16 parts of the curing enhancer prepared in Comparative Preparation Example 4, 3.6 parts of 1-benzylbenzene-2-ethylimidazole, 0.9 parts of 1-hydroxycyclohexyl phenone and 420 parts of anhydrous methanol; The preparation method of the epoxy resin comprises the following steps: The functionalized epoxy resin component, curing enhancer and 1-hydroxycyclohexyl phenone were added to anhydrous methanol, stirred at 660 rpm for 22 min until uniform, heated to 42 °C, and placed under a wavelength peak of 365 nm and an intensity of 80 mw / cm 2 The mixture was irradiated under ultraviolet light for 14 minutes, and 1-benzylbenzene-2-ethylimidazole was added. The temperature was raised to 54°C, the rotation speed was reduced to 500 rpm, and stirring was continued for 32 minutes. The rotary evaporation temperature was controlled at 62°C, and the anhydrous methanol was removed by rotary evaporation to obtain the epoxy resin.

[0037] Performance Testing Pour the epoxy resin prepared in Examples 1-3 and Comparative Examples 1-4 onto a clean tetrafluoroethylene plate, and apply it in sequence from 12 μm, 24 μm, 36 μm to 48 μm using a four-sided applicator, pre-cure at 90°C for 2 h, post-cure at 140°C for 4 h, then hot-press at 0.4 MPa and 140°C for 4 h, and separate the film from the tetrafluoroethylene plate with a scraper to obtain a sample.

[0038] 1. Mechanical properties The mechanical properties of the test samples, namely tensile modulus, tensile strength and elongation at break, were measured using the ASTM D882-12 material testing system; Impact resistance: According to GB / T13525-1992, the impact resistance of the samples was tested; Self-repairing property: Make a scratch of about 1mm in length on the surface of the sample, heat it at 90℃ for 2h, observe whether it is repaired, and then use tensile strength as the evaluation parameter of self-repairing rate. According to the calculation formula of self-repairing rate, calculate the self-repairing rate ɑ; make the sample into a dumbbell shape, cut it with a blade, the scratch depth is 2mm, heat it at 90℃ for 2h, and use a universal testing machine to perform tensile test on the system, the tensile rate is 2mm / min, the test condition is room temperature, and the experimental results are recorded. The calculation of repair efficiency is shown in formula (1): (1) In formula (1), ɑ repairde is the tensile strength after scratch repair, virgin is the initial tensile strength; The judgment criteria for whether to repair: if the self-repair rate is greater than 30%, it is yes; if it is less than or equal to 30%, it is no; Degradability: The epoxy resins provided in the above Examples 1-3 and Comparative Examples 1-4 were prepared into samples with a size of 50 mm×50 mm×5 mm, and each sample was immersed in 300 mL of ethanol at 110° C. for 2 h. The undissolved samples were collected by filtration and weighed after drying. The degradation rate was calculated. The calculation formula of the degradation rate is shown in Formula (2): (2) In formula (2), W a is the mass of epoxy resin sample before degradation (g), W b is the mass of the epoxy resin sample after degradation (g), and the above specific test results are shown in Table 1 below: Table 1 Performance test of epoxy resins obtained in Examples 1-3 and Comparative Examples 1-4

[0039] It can be seen from Table 1 that, compared with Comparative Examples 1-4, the epoxy resin prepared in Examples 1-3 not only has more excellent mechanical properties, but also has good self-healing properties and degradation rate.

[0040] 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. An epoxy resin, characterized in that The method comprises the following raw materials in parts by weight: 95-133 parts of a functionalized epoxy resin component, 16-32 parts of a curing enhancer, 3.6-7.4 parts of a curing accelerator and 0.9-1.3 parts of a photoinitiator; The structural formula of the functionalized epoxy resin component is as follows: The functionalized epoxy resin component is firstly prepared by a Schiff condensation reaction between 2,4-dihydroxybenzaldehyde and ethanolamine to obtain a Schiff base monomer, then an esterification reaction with p-hydroxycinnamic acid to obtain a modified monomer, and finally a nucleophilic substitution reaction with epichlorohydrin to obtain the functionalized epoxy resin component. The structural formula of the curing enhancer is as follows: 。 2. An epoxy resin according to claim 1, characterized in that: The functionalized epoxy resin component is prepared by the following steps: Step A1, adding 2,4-dihydroxybenzaldehyde and ethanolamine to anhydrous ethanol, stirring evenly, then adding glacial acetic acid, heating to reflux, stirring to react for 5-7h, rotary evaporation, washing, and drying to obtain a Schiff base monomer; Step A2, adding Schiff base monomer, p-toluenesulfonic acid and p-hydroxycinnamic acid into anhydrous ethanol, heating to 35-45° C., stirring evenly, then heating to reflux, stirring and reacting for 2-4 hours, rotary evaporation, washing, and drying to obtain a modified monomer; Step A3, ultrasonically disperse the modified monomer in anhydrous DMF, raise the temperature to 86-92°C while stirring, then add tetrabutylammonium bromide and toluene, add epichlorohydrin dropwise, control the dripping to be completed within 10 minutes, complete the dripping, stir and react for 3.6-4.2 hours, after the reaction is completed, cool to room temperature, add alkali solution dropwise while stirring, control the dripping to be completed within 30 minutes, continue stirring for 0.6-0.8 hours, add alkali solution dropwise again, control the dripping to be completed within 30 minutes, continue stirring for 1.8-2.2 hours, filter under reduced pressure, wash, and dry to obtain a functionalized epoxy resin component.

3. An epoxy resin according to claim 2, characterized in that: In the step A1, the mass ratio of 2,4-dihydroxybenzaldehyde, ethanolamine, anhydrous ethanol and glacial acetic acid is (4-6): (2.6-3.4): (42-56): (0.06-0.1).

4. An epoxy resin according to claim 2, characterized in that: In the step A2, the mass ratio of Schiff base monomer, p-toluenesulfonic acid, p-hydroxycinnamic acid and anhydrous ethanol is (4.2-5.6): (0.12-0.24): (3.8-5.0): (54-66).

5. An epoxy resin according to claim 2, characterized in that: In the step A3, the mass ratio of the modified monomer, methyl isobutyl ketone, tetrabutylammonium bromide, toluene, epichlorohydrin and the total amount of alkali solution is (5.4-6.6): (56-64): (0.04-0.06): (6-10): (2.4-3.0): (22-26), the alkali solution added dropwise for the first time is a sodium hydroxide aqueous solution with a mass fraction of 40-50%, and the alkali solution added dropwise for the second time is a sodium hydroxide aqueous solution with a mass fraction of 32-36%, and the masses of the alkali solutions added dropwise for the two times are the same.

6. An epoxy resin according to claim 1, characterized in that: The curing enhancer is prepared by the following steps: Step B1, add L-cysteine, trifluoromethanesulfonic acid and 3,3'-dithiodipropionic acid to anhydrous DMF, heat to 35-45°C, stir evenly, then heat to 72-84°C, continue stirring to react for 3.4-4.6h, rotary evaporate, wash, and dry to obtain a modified monomer; Step B2, add diethylenetriamine and modified monomer to anhydrous DMF, stir evenly, and drop a mixture of N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF while stirring. After the dropwise addition, heat to 72-78°C, stir to react for 3-5h, and after the reaction is completed, filter, wash and dry to obtain a curing enhancer.

7. An epoxy resin according to claim 6, characterized in that: In the step B1, the mass ratio of L-cysteine, trifluoromethanesulfonic acid, 3,3'-dithiodipropionic acid and anhydrous DMF is (3.6-4.4): (0.03-0.05): (2.1-2.7): (50-60).

8. An epoxy resin according to claim 6, characterized in that: In the step B2, the mass ratio of diethylenetriamine, disulfide monomer, anhydrous DMF and mixed solution a is (6-8): (20-26): (80-90): (30-40).

9. An epoxy resin according to claim 6, characterized in that: In the step B2, in the mixed solution a, the mass ratio of N,N-dicyclohexylcarbodiimide, 4-dimethylaminopyridine and anhydrous DMF is (5.6-7.2):(3.6-4.6):(23-27).

10. A method for preparing the epoxy resin according to any one of claims 1 to 9, characterized in that: The following steps are involved: The functionalized epoxy resin component, curing enhancer and photoinitiator are stirred evenly, heated to 42-46°C, irradiated with ultraviolet light for 14-18 minutes while stirring, and then a curing accelerator is added, heated to 54-62°C, and stirred for 32-46 minutes to obtain epoxy resin.

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