Epoxy resin interface fusion method based on ethylene glycol induction

Abstract

The epoxy resin interface fusion method based on ethylene glycol induction comprises the following steps: pretreating epoxy resin; ethylene glycol is added into the pretreated epoxy resin for a degradation reaction, and a degradation solution is generated; dropwise adding the degradation solution to the surface of epoxy resin to be bonded, and uniformly spreading; and putting the bonded epoxy resin into a heating environment for reaction to complete interface fusion. According to the method, the degradation solution of the epoxy resin is utilized, interface fusion is achieved under pressure-free treatment, thermal remodeling regeneration of the epoxy resin is achieved, an environment-friendly and sustainable recovery mode is provided, the risks of stress concentration and assembly connection in the interface fusion process are avoided, the limitation of a traditional interface fusion method is overcome, the connection efficiency is improved, and the production cost is reduced. The production cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy resin recovery, and in particular to an epoxy resin interface fusion method based on ethylene glycol induction. Background Art

[0002] Traditional epoxy resins are widely used in various electrical insulation materials due to their excellent insulation properties, thermal and mechanical stability, but due to their stable three-dimensional cross-linked chemical network structure, epoxy resins are difficult to degrade and recycle. In response to the recycling problem of epoxy resins, scholars have proposed anhydride-cured epoxy resins based on a dynamic cross-linked network structure. The thermal rearrangement characteristics and chemical degradation activity of the dynamic cross-linked network of epoxy resins give the material dual functions of thermal remodeling and chemical degradation regeneration.

[0003] Thermal reshaping recycling is a traditional physical recycling method, especially the physical recycling of waste electrical equipment. It faces the problems of high pressure required for interface fusion and solidification between powders during the recycling process, low recycling efficiency and high cost. In addition, traditional interface fusion may cause stress concentration and increase the risk of fracture.

[0004] In view of this, it is necessary to develop a method for epoxy resin interface fusion to overcome the limitations of traditional interface fusion methods and realize thermal reshaping and regeneration of epoxy resin powder to improve connection efficiency and reduce production costs, and avoid the risks of stress concentration and component connection during interface fusion. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes an epoxy resin interface fusion method based on ethylene glycol induction, and the specific technical scheme is as follows: A method for epoxy resin interface fusion based on ethylene glycol induction comprises the following steps: Pre-treating the epoxy resin; adding ethylene glycol into the pretreated epoxy resin to perform a degradation reaction to generate a degradation solution; Add the degradation solution dropwise onto the epoxy resin surface to be bonded and spread it evenly; The bonded epoxy resin is placed in a heated environment for reaction to complete interface fusion.

[0006] Furthermore, the pretreatment process is as follows: the epoxy resin is crushed into powder, and powder particles with a particle size less than 0.1 mm are screened.

[0007] Furthermore, the mass fraction of the ethylene glycol is 99% to 99.5%.

[0008] Furthermore, during the degradation reaction, the mass ratio of the epoxy resin powder to the ethylene glycol is 1:5-20.

[0009] Furthermore, the reaction temperature of the degradation reaction is 160° C. and the reaction time is 24 hours.

[0010] Furthermore, the amount of the degradation solution added to the epoxy resin to be bonded is 0.05 ml / cm 2 .

[0011] Furthermore, the reaction temperature in the heating environment during the interface fusion is 180° C., and the reaction time is 2 h.

[0012] Furthermore, the epoxy resin is an anhydride-cured epoxy resin, which is prepared with a bisphenol A epoxy resin matrix, methyltetrahydrophthalic anhydride as a curing agent and 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst.

[0013] Furthermore, the bisphenol A type epoxy resin matrix is ​​bisphenol A diglycidyl ether, wherein the molar ratio of bisphenol A diglycidyl ether, methyltetrahydrophthalic anhydride and 1,5,7-triazabicyclo[4.4.0]dec-5-ene is 1:1:0.04.

[0014] Furthermore, the thermal curing process of the synthesized epoxy resin is curing at 110° C. for 2 h, curing at 130° C. for 2 h, and curing at 150° C. for 3 h.

[0015] Beneficial effects: The present invention utilizes the degradation solution of epoxy resin to achieve interface fusion under pressure-free treatment, realizes thermal remodeling regeneration of epoxy resin, provides a green and sustainable recycling method, avoids the risks of stress concentration and component connection during interface fusion, overcomes the limitations of traditional interface fusion methods, improves connection efficiency, and reduces production costs. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0017] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0019] The raw materials used in the present invention are all commonly available in the market unless otherwise specified.

[0020] A method for epoxy resin interface fusion based on ethylene glycol induction comprises the following steps: (1) Pre-treat the epoxy resin.

[0021] The pretreatment process is as follows: the epoxy resin is crushed into powder by a molecular dynamic sieve, and powder particles with a particle size less than 0.1 mm are screened.

[0022] (2) Add ethylene glycol to the pretreated epoxy resin to carry out a degradation reaction to generate a degradation solution.

[0023] The mass fraction of the ethylene glycol is 99% to 99.5%. During the degradation reaction, the mass ratio of the epoxy resin powder to the ethylene glycol is 1:5 to 20. The reaction temperature of the degradation reaction is 160° C., and the reaction time is 24 hours.

[0024] (3) Add the degradation solution dropwise onto the epoxy resin surface to be bonded and spread it evenly.

[0025] The amount of degradation solution added to the epoxy resin to be bonded is 0.05 ml / cm 2 .

[0026] (4) The bonded epoxy resin is placed in a heated environment to react and complete the interface fusion.

[0027] The reaction temperature in the heating environment during interface fusion is 180°C, and the reaction time is 2h.

[0028] The mechanism of epoxy resin interface fusion induced by ethylene glycol is: When epoxy resin and ethylene glycol are mixed and heated to above the bond exchange activation temperature, the hydroxyl groups in the ethylene glycol will undergo a bond exchange reaction with the ester bonds in the epoxy resin network; this process causes the macromolecular chains in the molecular chain network containing ester bonds to break, thereby initiating the degradation of the epoxy resin. After degradation, the ethylene glycol small molecule solvent evaporates due to its strong diffusivity and evaporation ability, leaving the degraded monomers or oligomers as reaction precursors, which then repolymerize to form a solid polymer cross-linked network. When this degradation and re-cross-linking process occurs at the interface of the two resins to be connected, a pressure-free connection can be achieved.

[0029] The specific embodiments are as follows: Embodiment 1: (1) Preparation of epoxy resin The epoxy resin is an anhydride-cured epoxy resin, which is prepared with a bisphenol A epoxy resin matrix, methyltetrahydrophthalic anhydride as a curing agent and 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst.

[0030] Specifically, the bisphenol A type epoxy resin matrix is ​​bisphenol A diglycidyl ether, wherein the molar ratio of bisphenol A diglycidyl ether, methyltetrahydrophthalic anhydride and 1,5,7-triazabicyclo[4.4.0]dec-5-ene is 1:1:0.04.

[0031] Add bisphenol A diglycidyl ether to 1,5,7-triazabicyclo[4.4.0]dec-5-ene, stir at 90°C for 10 minutes using a magnetic stirrer, evacuate for 10 minutes, add methyltetrahydrophthalic anhydride, stir at 90°C for 10 minutes, evacuate for 10 minutes, pour into a mold, and cure at 110°C for 2 hours, 130°C for 2 hours, and 150°C for 3 hours in sequence to prepare an adaptive thermosetting resin.

[0032] (2) Interface fusion The anhydride-cured epoxy resin prepared above was crushed into particles, and a molecular dynamic sieve was used to vibrate for half an hour to screen out powders smaller than 0.1 mm; 1 g of the powder was weighed and mixed with 5 g of ethylene glycol, and degraded at 160° C. for 24 hours; and the particle size was adjusted to 0.05 ml / cm 2 Take the degradation solution and add it dropwise to the epoxy resin surface to be interfacially fused and bonded. Press and rub gently to spread it out better. Put the bonded sample into an oven at a temperature of 180°C for 2 hours.

[0033] (3) Sample test DMA was used to carry out uniaxial tensile test and T-tear test to test the effective elastic modulus and average tear force of the epoxy resin after interface fusion.

[0034] Embodiment 2: Based on step (2) of Example 1, the mass ratio of the anhydride-cured epoxy resin powder to the ethylene glycol is 1:10, and the interface fusion of the epoxy resin is carried out according to the above steps.

[0035] Embodiment 3: Based on step (2) of Example 1, the mass ratio of the anhydride-cured epoxy resin powder to the ethylene glycol is 1:15, and the interface fusion of the epoxy resin is carried out according to the above steps.

[0036] Embodiment 4: Based on step (2) of Example 1, the mass ratio of the anhydride-cured epoxy resin powder to ethylene glycol is 1:20, and the interface fusion of the epoxy resin is carried out according to the above steps.

[0037] The data after the sample test of the above embodiment is as follows:

[0038] According to the above embodiments and test data, the mass ratio of epoxy resin powder to ethylene glycol is 1:10, which is more suitable. When the mass ratio is 1:10, the effective elastic modulus of the epoxy resin sample after interface fusion is 0.88, and the average tear force is 6.9N. It can achieve interface fusion under pressure-free treatment and realize thermal remodeling and regeneration of epoxy resin. This method has a wide range of application prospects. It does not require additional force to be applied during the physical recycling of discarded electrical equipment, simplifies the recycling operation, and has important application value and economic benefits.

[0039] It should be noted that the uniaxial tensile test of the interface fusion specimens was carried out on a DMA testing machine to study the stress-strain behavior of the interface fusion connected specimens at room temperature. A loading rate of 5% / min was selected to minimize the elastic effect. For each tension test, at least four specimens were tested and the average value was reported.

[0040] It should be noted that bisphenol A diglycidyl ether, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, methyltetrahydrophthalic anhydride and ethylene glycol were provided by Chengdu Cologne Chemical Co., Ltd.; the manufacturer of the oven was Shanghai Yiheng Scientific Instrument Co., Ltd., the manufacturer of the crusher was Deqing Xieda E-Commerce Co., Ltd., the manufacturer of the molecular dynamic sieve was Zibo Hengsen Building Installation Engineering Co., Ltd., and the manufacturer of the dynamic thermal mechanical analyzer (DMA) was TA Company of the United States, model Q800.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for epoxy resin interface fusion based on ethylene glycol induction, characterized in that: The following steps are involved: Pre-treating the epoxy resin; adding ethylene glycol into the pretreated epoxy resin to perform a degradation reaction to generate a degradation solution; Add the degradation solution dropwise onto the epoxy resin surface to be bonded and spread it evenly; The bonded epoxy resin is placed in a heated environment for reaction to complete interface fusion.

2. The interface fusion method according to claim 1, characterized in that: The pretreatment process is as follows: the epoxy resin is crushed into powder, and the powder particles with a particle size less than 0.1 mm are screened.

3. The interface fusion method according to claim 1, characterized in that: The mass fraction of the ethylene glycol is 99% to 99.5%.

4. The interface fusion method according to claim 2, characterized in that: During the degradation reaction, the mass ratio of the epoxy resin powder to the ethylene glycol is 1:5-20.

5. The interface fusion method according to claim 3, characterized in that: The reaction temperature of the degradation reaction is 160° C. and the reaction time is 24 h.

6. The interface fusion method according to claim 1, characterized in that: The amount of degradation solution added to the epoxy resin to be bonded is 0.05ml / cm 2 .

7. The interface fusion method according to claim 1, characterized in that: The reaction temperature in the heating environment during interface fusion is 180°C and the reaction time is 2h.

8. The interface fusion method according to any one of claims 1 to 7, characterized in that: The epoxy resin is an anhydride-cured epoxy resin, which is prepared with a bisphenol A epoxy resin matrix, methyltetrahydrophthalic anhydride as a curing agent and 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst.

9. The interface fusion method according to claim 8, characterized in that: The bisphenol A type epoxy resin matrix is ​​bisphenol A diglycidyl ether, wherein the molar ratio of bisphenol A diglycidyl ether, methyltetrahydrophthalic anhydride and 1,5,7-triazabicyclo[4.4.0]dec-5-ene is 1:1:0.

04.

10. The interface fusion method according to claim 9, characterized in that: The thermal curing process of the synthesized epoxy resin is curing at 110°C for 2h, curing at 130°C for 2h, and curing at 150°C for 3h.

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