Recyclable epoxy resin, system material and composite material thereof, and recovery methods therefor

Abstract

The present invention relates to the technical field of epoxy resin recovery. Provided are a recyclable epoxy resin, a system material and composite material thereof, and recovery methods therefor. Said recyclable epoxy resin system material comprises an epoxy resin portion and a curing agent portion, the weight ratio of the epoxy resin portion to the curing agent portion being 100:(20-105). A swelling additive is added to the epoxy resin portion, the content of the swelling additive being 0.0001-15 wt% calculated on the basis of the weight percentage in the epoxy resin portion. The swelling additive is micron-sized solid particles, is always present in a powdery state in the recyclable epoxy resin system material and a cured product thereof, and undergoes a swelling reaction upon encountering a degradation solvent. The present invention overcomes the challenges in the prior art of the high operation difficulty, high costs, solvent control, and environmentally-friendly treatment of dissolved small-molecule compounds due to the need to synthesize a novel epoxy structure during preparation of recyclable epoxy resins and epoxy resin composite materials thereof, and achieving the degradation and recycling of thermosetting epoxy resin materials and composite materials thereof.

Description

Recyclable epoxy resin and its system material, composite material and recycling method

[0001] Cross-references

[0002] This application claims priority to Chinese application No. 2023107185421, filed on June 16, 2023. The contents of the above application are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of recyclable epoxy resins, in particular to a recyclable epoxy resin and a system material, a composite material and a recycling method thereof. Background Art

[0004] Epoxy resin is a thermosetting polymer material with excellent performance. It has good mechanical properties, bonding properties, dimensional stability, chemical corrosion resistance and electrical insulation. It is used to make adhesives, corrosion-resistant coatings, electrical insulation materials and fiber-reinforced composite materials. It has a wide range of applications in aerospace, automobiles and ships, wind turbine blades, sporting goods, electronic appliances and other fields.

[0005] The epoxy resin system material includes an epoxy resin part and a curing agent part. When used, the resin part and the curing agent part are mixed and cured to obtain an epoxy resin product. Epoxy resin composite materials are composite materials composed of epoxy resin as a matrix and fibers and the like as reinforcing materials. After curing, epoxy resin forms a three-dimensional cross-linked network, in which the carbon-carbon bonds and carbon-oxygen bonds are irreversible covalent chemical bonds, which makes the cured epoxy resin insoluble and infusible, and difficult to degrade or reprocess and recycle. Therefore, when large-scale epoxy resin products and epoxy resin and fiber composite materials (such as wind turbine blades) are updated, efficiently degrading, recycling and reusing the basic materials in waste products and ensuring their performance has become a major technical difficulty.

[0006] At present, the recycling methods for waste thermosetting fiber reinforced composite materials mainly include mechanical recycling, thermal energy recovery and chemical recycling. Among them, mechanical recycling refers to crushing waste composite materials and directly using them as fillers. Although this method is simple to operate and has a high recovery rate, it is only applicable to uncontaminated materials and cannot recover long fibers in the composite materials. Thermal energy recovery refers to directly burning waste composite materials to obtain heat energy. Although this method has also been industrialized, it is inefficient and not suitable for materials with a high fiber content. Chemical recycling refers to decomposing the resin in waste composite materials into small molecules by heating or using solvents, thereby separating the resin and the fibers. Although this method is expected to simultaneously recover the resin and long fibers (carbon fibers) in the composite materials, the solvents often used are highly corrosive, unsafe to operate, and have high equipment requirements and are expensive. In addition, the collection and treatment of small molecules dissolved in the solution is also a major problem.

[0007] Various methods for recycling waste epoxy resin composites using solvents have been developed, but most require synthesizing new epoxy structures, which is difficult and costly. They also lack detailed information on how to dispose of used solvents and effectively collect and process the small molecules dissolved in them. Furthermore, most chemical recycling methods use controlled solvents, such as concentrated hydrochloric acid, which are difficult to manage and store.

[0008] Therefore, it is necessary to provide a novel recyclable epoxy resin and its system material, composite material and recycling method to solve the above-mentioned problems existing in the prior art.

[0009] Summary of the Invention

[0010] The purpose of the present invention is to provide a recyclable epoxy resin and its system material, composite material and recycling method, so as to solve the difficulties in the prior art in preparing recyclable epoxy resin and its composite material, such as the need to synthesize a new epoxy structure, the high difficulty and high cost of operation, the difficulty in controlling the degradation solvent, and the green treatment of dissolved small molecule compounds, so as to realize the degradation and recycling of thermosetting material epoxy resin and its composite material.

[0011] In a first aspect, the present invention provides a recyclable epoxy resin system material, which adopts the following technical solution:

[0012] A recyclable epoxy resin system material comprises an epoxy resin portion and a curing agent portion, wherein the weight ratio of the epoxy resin portion to the curing agent portion is 100:(20-105); a swelling additive is added to the epoxy resin portion, and the content of the swelling additive is 0.0001-15 wt% in terms of weight percentage of the epoxy resin portion; the swelling additive is micron-sized solid particles, is always present in the recyclable epoxy resin system material and its cured product in a powdered state, and undergoes a swelling reaction upon encountering a degradation solvent.

[0013] By adopting the above technical solution, micron-sized solid particles that are always present in a powdery state in the recyclable epoxy resin system material are selected as a swelling additive and added to the system material. The swelling additive does not react with the epoxy resin portion and the curing agent portion of the system material and remains in a powdery state in the epoxy resin cross-linking system after curing (that is, in the cured product of the recyclable epoxy resin system material). Epoxy resin is a thermosetting material. The epoxy resin after curing has the characteristics of being insoluble and infusible. The degradation solvent has little effect on the cured epoxy resin cross-linking system, but has a greater effect on the swelling additive dispersed therein. During degradation, the swelling additive encounters the degradation solvent, absorbs the solvent, and swells due to the different degrees of solvent absorption by the recyclable epoxy resin and the swelling additive. This causes cracks in the cured recyclable epoxy resin, thereby causing the cured product to rupture and decompose into lumps with a diameter of less than 1 mm. The decomposed lumps are extremely easy to separate and can be directly sieved out, thereby realizing the recovery of the recyclable epoxy resin. The entire process does not require the synthesis of new epoxy structures, and the degraded solvent can be reused, so the operation is relatively easy and the cost is low. At the same time, by controlling the amount of swelling additives, the prepared recyclable epoxy resin has no obvious defects or impurities, and its mechanical properties remain largely unchanged compared to traditional epoxy resins and composite materials, and some properties are even improved.

[0014] Preferably, the swelling additive is selected from one or more of amino acid additives, powder solids containing reversible covalent bonds and inorganic compounds.

[0015] Preferably, the swelling additive is selected from L-cystine, glyoxal bis(o-aminophenol), benzyl-2-naphthylamine, dibenzylhydrazine, N,N'-bis(2-aminobenzylidene)ethylenediamine, polyanilinehydrazine, N,N'-bis(5-hydroxysalicylidene)ethylenediamine, N,N'-diphenylformamidine, N,N'-bis(salicylidene)-1,2-propylenediamine, salicylaldehyde azine, N,N'-bis(salicylidene)ethylenediamine, benzyldioxime, At least one of glyoxime, salicylaldehyde oxime, salicylaldehyde semicarbazone, N-phenylbenzamidine, 4'-ethoxybenzylidene-4-butylaniline, N-benzylidene aniline, calcium carbonate, DL-methionine, S-benzyl-L-cysteine, N-(4-methoxybenzylidene)-4-butylaniline, N-(4-methoxybenzylidene)aniline, N-benzylidene-p-toluidine, N-benzylidenemethylamine and trans-N-(2-pyridylmethylene)aniline.

[0016] Preferably, the swelling additive is one or a mixture of L-cystine, calcium carbonate, DL-methionine, S-benzyl-L-cysteine, glyoxal bis(o-aminophenol) and benzildioxime.

[0017] In a second aspect, the present invention provides a recyclable epoxy resin prepared using the above-mentioned system material, using the following technical solution:

[0018] A recyclable epoxy resin is prepared using the recyclable epoxy resin system material by the following steps: S1, adding the swelling additive to the epoxy resin part and mixing them evenly; S2, mixing the epoxy resin part and the curing agent part obtained in step S1 in proportion, and curing them to obtain the recyclable epoxy resin.

[0019] By adopting the above technical solution, the system materials are designed, the amount of swelling additives is selected and controlled, and no new structure is synthesized. The use and curing of the system materials are not difficult. The recyclable epoxy resin prepared has no obvious defects or impurities, and the mechanical properties remain largely unchanged, and some properties are even improved.

[0020] In a third aspect, the present application provides a method for recycling the above-mentioned recyclable epoxy resin, which adopts the following technical solution:

[0021] A method for recovering the recyclable epoxy resin comprises the following steps:

[0022] T1, immersing the recyclable epoxy resin in a degradation solvent for degradation;

[0023] The degradation solvent is at least one of water, dilute acid, alkaline solution, benzene, halogenated hydrocarbons, ethers and alcohols.

[0024] By adopting the above technical solution, the degradation conditions are low and easy to achieve. When the recycling method of the present application is adopted, the recyclable epoxy resin is cracked to form small pieces or powders of epoxy resin with a diameter of less than 1 mm, which are easy to separate. At the same time, the separated epoxy resin powder can be recycled and used as filler, and the degradation solvent can also be reused without affecting the decomposition efficiency of subsequent use, thereby overcoming the difficulties of solvent control and how to dissolve small molecule compounds in a green way.

[0025] Preferably, the degradation solvent is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide and dimethyl sulfoxide.

[0026] Preferably, the degradation solvent is 0.1 mol / L-1 mol / L glacial acetic acid or 0.1 mol / L-1 mol / L Bu3P / DMF.

[0027] By adopting the above technical solution, glacial acetic acid and Bu3P / DMF are non-regulated solutions, which are relatively safe, have little harm, have little impact on equipment, and can be reused. They do not affect the decomposition efficiency of recyclable epoxy resin in the subsequent recycling process. Using a concentration of 0.1 mol / L-1 mol / L, the degradation conditions are milder.

[0028] In a fourth aspect, the present application provides a recyclable epoxy resin composite material, which adopts the following technical solution:

[0029] A recyclable epoxy resin composite material includes reinforcing fibers and the aforementioned recyclable epoxy resin system. The prepared recyclable epoxy resin composite material containing additives has no obvious defects or impurities, and its mechanical properties remain largely unchanged, with some properties even being improved.

[0030] By adopting the above technical solution, the selected swelling additive is always present in the recyclable epoxy resin system material and its cured product in a powder state. The swelling additive does not react with the reinforcing fiber and only exists in the recyclable epoxy resin composite material in a powder state. The particle size of the swelling additive is controlled to be at the micron level while its content is controlled. This enables the obtained recyclable epoxy resin composite material to be degraded and recycled while ensuring that the mechanical properties of the material are not affected.

[0031] Preferably, the reinforcing fiber is glass fiber or carbon fiber.

[0032] Preferably, the reinforcing fibers and the recyclable epoxy resin system material are prepared by a vacuum infusion method to obtain the recyclable epoxy resin composite material.

[0033] In a fifth aspect, the present application provides a method for recycling the above-mentioned recyclable epoxy resin composite material, which adopts the following technical solution:

[0034] A method for recycling a recyclable epoxy resin composite material comprises the following steps:

[0035] P1, cutting the recyclable epoxy resin composite material into blocks;

[0036] P2, immersing the recyclable epoxy resin composite material cut into blocks in step P1 in a degradation solvent for degradation;

[0037] The degradation solvent is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide and dimethyl sulfoxide.

[0038] By adopting the above technical solution, the swelling additive does not react with the epoxy resin part, the curing agent part, or the reinforcing fiber. When cutting and soaking for degradation, the swelling additive absorbs the solvent and swells, causing cracks in the epoxy resin system of the recyclable epoxy resin composite material, thereby realizing the recovery of the resin in the recyclable epoxy resin composite material; the epoxy resin system of the recyclable epoxy resin composite material can be broken into small pieces and powder to a large extent, thereby separating the resin and the fiber, but a small part will be attached to the long fiber (although it cannot be completely recovered, it is expected that the resin and fiber in the composite material will be recovered at the same time); further, the degradation conditions of the present application are mild, and the degradation solvent used can be physically separated and reused, which is green and environmentally friendly.

[0039] Preferably, the degradation solvent is 0.1 mol / L-1 mol / L glacial acetic acid or 0.1 mol / L-1 mol / L Bu3P / DMF.

[0040] In summary, this application includes at least one of the following beneficial technical effects:

[0041] 1. Micron-sized solid particles that are always present in a powdered state in a recyclable epoxy resin system material are selected as a swelling additive and added to the system material. The swelling additive does not react with the epoxy resin portion and the curing agent portion of the system material and remains in a powdered state in the cross-linked epoxy resin system after curing. During degradation, the swelling additive encounters the degradation solvent, absorbs the solvent, and swells, taking advantage of the different degrees of solvent absorption by the recyclable epoxy resin and the swelling additive. This causes cracks in the cured recyclable epoxy resin, thereby causing the cured product to rupture and decompose. The lumps after rupture and decomposition are extremely easy to separate and can be directly sieved out, and the degradation solvent can continue to be used, thereby achieving the recycling of the thermosetting material - the recyclable epoxy resin, without the need to synthesize a new epoxy structure, with low operation difficulty and low cost.

[0042] 2. By selecting and controlling the amount of swelling additives, the prepared recyclable epoxy resin and composite materials have no obvious defects or impurities, and the mechanical properties remain largely unchanged, and some properties are even improved.

[0043] 3. Through the coordinated design of the degradation solvent and the swelling additive, the recycling method provided in this application has mild degradation conditions, and breaks and decomposes to form recyclable epoxy resin powder with a diameter of less than 1 mm, which can be directly sieved out. The degradation solvent can be reused, which is green and environmentally friendly, simple to operate, and cost-controllable, and has strong practical significance. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the technical terms or scientific terms used herein should be the common meanings understood by people with ordinary skills in the field to which the invention belongs. The words "including" and similar words used in this article mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0045] In order to overcome the problems existing in the prior art, the embodiments of the present invention provide a recyclable epoxy resin and its system material, composite material and recycling method, so as to solve the problems in the prior art of preparing recyclable epoxy resin and its composite material, which require the synthesis of new epoxy structures, the high difficulty and high cost of operation, the difficulty in controlling degradation solvents, and the green treatment of dissolved small molecule compounds, thereby realizing the degradation and recycling of epoxy resin and its composite material as a thermosetting material.

[0046] In some embodiments of the present invention, the recyclable epoxy resin system material includes an epoxy resin part and a curing agent part, and the weight ratio of the epoxy resin part to the curing agent part is 100:(20-105); a swelling additive is added to the epoxy resin part, and the content of the swelling additive is 0.0001-15wt% as a percentage of the weight of the epoxy resin part; the swelling additive is a micron-sized solid particle, and the swelling additive is always present in a powder state in the recyclable epoxy resin system material and its cured product, and undergoes a swelling reaction after encountering a degradation solvent.

[0047] In some embodiments of the present invention, the particle size of the swelling additive is 600-1000 mesh.

[0048] In some embodiments of the present invention, the swelling additive is selected from one or more of amino acid additives, powdered solids containing reversible covalent bonds and inorganic compounds.

[0049] In some specific embodiments of the present invention, the amino acid additives include L-cystine, DL-methionine and S-benzyl-L-cysteine.

[0050] In some specific embodiments of the present invention, the swelling additives include swelling additives containing reversible covalent bonds and swelling additives without reversible covalent bonds. Swelling additives containing reversible covalent bonds include disulfide bond additives and imine bond additives.

[0051] In some specific embodiments of the present invention, the disulfide bond additives include L-cystine and cysteine.

[0052] In some specific embodiments of the present invention, imine bond additives include glyoxal bis(o-aminophenol), benzylene-2-naphthylamine, dibenzylhydrazine, N,N'-bis(2-aminobenzylidene)ethylenediamine, polyaniline hydrazine, N,N'-bis(5-hydroxysalicylidene)ethylenediamine, N,N'-diphenylformamidine, N,N'-bis(salicylidene)-1,2-propylenediamine, salicylaldehyde azine, N,N'-bis (Salicylidene)ethylenediamine, benzildioxime, glyoxime, salicylidenealdehyde oxime, salicylidenealdehyde semicarbazone, N-phenylbenzamidine, 4'-ethoxybenzylidene-4-butylaniline, N-benzylidene aniline, N-(4-methoxybenzylidene)-4-butylaniline, N-(4-methoxybenzylidene)aniline, N-benzylidene-p-toluidine, N-benzylidenemethylamine, and trans-N-(2-pyridylmethylene)aniline. Among them, the CAS number of polyaniline hydrazine is 2299-73-2.

[0053] In some embodiments of the present invention, the swelling additive is calcium carbonate, and the particle size of the calcium carbonate is 600-1000 mesh.

[0054] In some embodiments of the present invention, the swelling additive is one or a mixture of L-cystine, calcium carbonate, DL-methionine, S-benzyl-L-cysteine, glyoxal bis(o-aminophenol) and benzildioxime.

[0055] In some embodiments of the present invention, the weight ratio of the epoxy resin portion to the curing agent portion is any value within 100:(20-105). This weight ratio relationship is determined based on the appropriate ratio of the epoxy resin and the curing agent in the two-component system material in actual applications. Within this range, the effect of the addition of the swelling additive is controllable, does not affect the process, and has negligible effects on the properties of the cured product and the composite material. Any selection within the range is preferred.

[0056] In some embodiments of the present invention, the recyclable epoxy resin is prepared using a recyclable epoxy resin system material by the following steps: S1: adding a swelling additive to the epoxy resin portion and mixing uniformly; S2: mixing the epoxy resin portion obtained in step S1 with a curing agent portion in appropriate proportions and curing to obtain the recyclable epoxy resin. The preparation steps for the recyclable epoxy resin are simple and the industrial conditions are mature. The prepared recyclable epoxy resin has no obvious defects and exhibits excellent mechanical properties.

[0057] In some embodiments of the present invention, step S2 further includes: mixing the epoxy resin portion and the curing agent portion, heating the mixture at 30°C for 4 hours, then raising the temperature to 70°C and continuing heating for 10 hours to produce a recyclable epoxy resin. Specifically, the composition of the curing agent portion and the curing reaction between the epoxy resin portion and the curing agent portion are conventional methods in the art and will not be further described here.

[0058] The excellence of the technical solution of this application is that the existing epoxy resin system materials on the market can be modified by adding a range of swelling additives to the epoxy resin part to achieve the degradation and recycling requirements of the cured products of the system materials and the composite materials.

[0059] In some embodiments of the present invention, a method for recovering recyclable epoxy resin comprises the following steps:

[0060] T1, immersing the recyclable epoxy resin in a degradation solvent for degradation;

[0061] The degradation solvent is at least one of water, dilute acid, alkaline solution, benzene, halogenated hydrocarbons, ethers and alcohols.

[0062] In some embodiments of the present invention, before step T1, the process further includes: cutting the recyclable epoxy resin into recyclable epoxy resin blocks, so as to facilitate immersing the larger recyclable epoxy resin in the degradation solvent for degradation.

[0063] In some embodiments of the present invention, the degradation solvent used in step T1 is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropyl alcohol, butanol, isobutyl alcohol, tert-butyl alcohol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide, and dimethyl sulfoxide. Bu3P / DMF is a dimethylformamide solution of tributylphosphine.

[0064] In some embodiments of the present invention, the degradation solvent used in step T1 is 0.1 mol / L-1 mol / L glacial acetic acid or 0.1 mol / L-1 mol / L Bu3P / DMF.

[0065] Specifically, glacial acetic acid can be used undiluted, but it is more volatile. A diluted solution is relatively safe, has a low flash point, is less volatile, and has minimal impact on equipment. Using a 0.1-1 mol / L glacial acetic acid solution not only provides mild degradation conditions but also improves decomposition efficiency.

[0066] In some embodiments of the present invention, step T1 further comprises: immersing the recyclable epoxy resin in a degradation solvent at a temperature of 25-150° C. for degradation. Mild degradation conditions and low recycling temperatures save energy. The higher the heating temperature, the faster the decomposition.

[0067] In some embodiments of the present invention, step T1 further comprises: immersing the recyclable epoxy resin in a degradation solvent and heating and stirring. Both heating and stirring can accelerate the degradation of the recyclable epoxy resin.

[0068] In some specific embodiments of the present invention, the recyclable epoxy resin is degraded into lumps with a diameter of less than 1 mm. The decomposed lumps can be directly sieved out with a sieve, and the separated epoxy resin can be recycled and used as a filler, which is easy to handle.

[0069] In some embodiments of the present invention, the recyclable epoxy resin composite material includes reinforcing fibers and a recyclable epoxy resin system material.

[0070] In some embodiments of the present invention, the reinforcing fibers are glass fibers or carbon fibers.

[0071] In some embodiments of the present invention, the reinforcing fibers and the recyclable epoxy resin system material are prepared by vacuum infusion to obtain a recyclable epoxy resin composite material.

[0072] Specifically, vacuum infusion is one of the existing mainstream processes. The swelling additive added in the technical solution of this application is always in the form of powdered micron-sized solid particles in the recyclable epoxy resin system material and its cured product, which has little impact on the subsequent manufacturing process and meets the requirements of the vacuum infusion process.

[0073] In some embodiments of the present invention, a method for recycling a recyclable epoxy resin composite material comprises the following steps:

[0074] P1, cutting the recyclable epoxy resin composite material into blocks;

[0075] P2, immersing the recyclable epoxy resin composite material cut into blocks in step P1 in a degradation solvent for degradation;

[0076] The degradation solvent is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide and dimethyl sulfoxide.

[0077] Considering that composite materials are generally large in size, they need to be cut before being immersed and degraded using the recycling method of the present application.

[0078] In other embodiments of the present invention, the method for recycling recyclable epoxy resin includes a pretreatment step of cutting the recyclable epoxy resin into blocks before step T1.

[0079] In some embodiments of the present invention, the degradation solvent used in step P2 is 0.1 mol / L-1 mol / L glacial acetic acid or 0.1 mol / L-1 mol / L Bu3P / DMF.

[0080] In some embodiments of the present invention, step P2 further comprises immersing the recyclable epoxy resin composite material cut into blocks in step P1 in a degradation solvent at a temperature of 25-150°C. After immersion for 16 hours to one week, the recycled epoxy resin composite material decomposes into epoxy resin blocks with a diameter of less than 1 cm. Mild degradation conditions and low recycling temperatures save energy. Higher heating temperatures result in faster decomposition.

[0081] In some specific embodiments of the present invention, the recyclable epoxy resin composite material is degraded into blocks with a diameter of less than 1 cm. The decomposed blocks can be directly sieved out with a sieve, and the separated epoxy resin can be recycled and used as a filler, which is easy to handle.

[0082] In some embodiments of the present invention, step P2 includes: immersing the recyclable epoxy resin composite material cut into blocks in step P1 in a degradation solvent and heating and stirring.

[0083] Example

[0084] Taking the epoxy resin system material currently used in large quantities on the market as an example, it is purchased from Daosheng Tianhe Materials Technology (Shanghai) Co., Ltd., with the brand name TECHSTORM190 / 195, a two-component material, TS190 as epoxy resin and TS195 as curing agent.

[0085] The glass fiber takes E7-UD1250 produced by Zhejiang Hengshi Fiber Industry Co., Ltd. as an example; the carbon fiber takes UD carbon fabric produced by Saertex as an example.

[0086] Example 1

[0087] Preparation of recyclable epoxy resin: 0.05g of L-cystine was added to 100g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The L-cystine content was 0.05% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent (i.e., TS195 curing agent) was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then raised to 70°C and heated for an additional 10 hours to cure, yielding the recyclable epoxy resin.

[0088] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm×5 cm×3 mm. The small pieces were then completely immersed in 0.5 mol / L glacial acetic acid and heated at 70° C. to partially degrade within 23 hours.

[0089] Preparation of a recyclable epoxy resin composite: 0.05g of L-cystine was added to 100g of TS190 epoxy resin and mixed evenly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed evenly to prepare an epoxy resin mixture. The L-cystine content was 0.05% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed. The epoxy resin mixture was introduced into the vacuum infusion platform and impregnated the glass fibers. The mixture was then heated at 70°C for 10 hours to obtain the recyclable epoxy resin composite.

[0090] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0091] In the context of this application, "epoxy resin system" means an epoxy resin cross-linked system formed by curing a recyclable epoxy resin system material.

[0092] Example 2

[0093] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in Example 1 was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 21 hours.

[0094] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in Example 1 was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. Most of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0095] Example 3

[0096] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in Example 1 was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 60°C. The recyclable epoxy resin was partially degraded within 20 hours.

[0097] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in Example 1 was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 1 mol / L glacial acetic acid and heated at 60°C. Most of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0098] Example 4

[0099] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in Example 1 was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 0.05 mol / L Bu3P / DMF (tributylphosphine / dimethylformamide solution) and left at room temperature. The recyclable epoxy resin was completely degraded within 1 week.

[0100] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in Example 1 was cut into small pieces of 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 0.05 mol / L Bu3P / DMF and left at room temperature. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within one week.

[0101] Example 5

[0102] Preparation of a recyclable epoxy resin composite: 0.05g of L-cystine was added to 100g of TS190 epoxy resin and mixed evenly. 28g of TS195 curing agent was then added to the epoxy resin and mixed evenly. This epoxy resin mixture contained 0.05% L-cystine by weight of the epoxy resin, and the weight ratio of epoxy resin to curing agent was 100:28. A four-layer carbon fiber vacuum infusion platform was constructed, and the epoxy resin mixture was introduced into the platform to impregnate the carbon fibers. The recyclable epoxy resin composite was then heated at 70°C for 10 hours.

[0103] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0104] Example 6

[0105] Preparation of recyclable epoxy resin: 0.03g of DL-methionine was added to 100g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The DL-methionine content was 0.03% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and continued to heat for 10 hours to produce the recyclable epoxy resin.

[0106] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours.

[0107] Preparation of a recyclable epoxy resin composite: 0.03g of DL-methionine was added to 100g of TS190 epoxy resin and mixed uniformly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed uniformly to prepare an epoxy resin mixture. The DL-methionine content was 0.03% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed. The epoxy resin mixture was introduced into the vacuum infusion platform and impregnated the glass fibers. The epoxy resin composite was then heated at 70°C for 10 hours to obtain the recyclable epoxy resin composite.

[0108] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0109] Example 7

[0110] Preparation of recyclable epoxy resin: 0.3g DL-methionine was added to 100g TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The DL-methionine content was 0.3% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and continued to heat for 10 hours to produce the recyclable epoxy resin.

[0111] Degradation of Recyclable Epoxy Resin: The recyclable epoxy resin prepared in this example was cut into small pieces approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours. The volume of the resulting epoxy resin pieces after degradation was significantly smaller than that of the epoxy resin pieces after degradation in Example 6.

[0112] Preparation of a recyclable epoxy resin composite: 0.3g of DL-methionine was added to 100g of TS190 epoxy resin and mixed evenly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed evenly to prepare the epoxy resin mixture. The DL-methionine content was 0.3% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed. The epoxy resin mixture was introduced into the vacuum infusion platform and impregnated the glass fibers. The mixture was then heated at 70°C for 10 hours to obtain the recyclable epoxy resin composite.

[0113] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0114] Example 8

[0115] Preparation of recyclable epoxy resin: 0.15g of 800-mesh calcium carbonate was added to 100g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The calcium carbonate content was 0.15% by weight of the epoxy resin portion, and the weight ratio of epoxy resin to curing agent was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and continued to heat for 10 hours to produce the recyclable epoxy resin.

[0116] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours.

[0117] Preparation of a recyclable epoxy resin composite: 0.15g of 800-mesh calcium carbonate was added to 100g of TS190 epoxy resin and mixed evenly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed evenly to prepare the epoxy resin mixture. The calcium carbonate content was 0.15% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed. The epoxy resin mixture was introduced into the vacuum infusion platform and impregnated the glass fibers. The mixture was then heated at 70°C for 10 hours to obtain the recyclable epoxy resin composite.

[0118] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0119] Example 9

[0120] Preparation of recyclable epoxy resin: 2.5 g of S-benzyl-L-cysteine ​​was added to 97.5 g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28 g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The S-benzyl-L-cysteine ​​content was 2.5% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and continued to heat for 10 hours to produce the recyclable epoxy resin.

[0121] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours.

[0122] Preparation of a recyclable epoxy resin composite: 2.5g of S-benzyl-L-cysteine ​​was added to 97.5g of TS190 epoxy resin and mixed evenly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed evenly. The S-benzyl-L-cysteine ​​content was 2.5% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. This epoxy resin mixture was prepared. A four-layer glass fiber vacuum infusion platform was constructed, and the epoxy resin mixture was introduced into the vacuum infusion platform to impregnate the glass fibers. The recyclable epoxy resin composite was then heated at 70°C for 10 hours.

[0123] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0124] Example 10

[0125] Preparation of recyclable epoxy resin: 10g of glyoxal bis(o-aminophenol) acetal was added to 90g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly. The glyoxal bis(o-aminophenol) acetal content was 10% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. This yielded an epoxy resin mixture. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and heated for a further 10 hours to produce the recyclable epoxy resin.

[0126] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours.

[0127] Preparation of a recyclable epoxy resin composite: 10g of glyoxal bis(o-aminophenol) acetal was added to 90g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce the epoxy resin mixture. The glyoxal bis(o-aminophenol) acetal content was 10% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed, and the epoxy resin mixture was introduced into the vacuum infusion platform, impregnating the glass fibers. The mixture was then heated at 70°C for 10 hours to produce the recyclable epoxy resin composite.

[0128] Degradation of recyclable epoxy resin composite material: The recyclable epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the recyclable epoxy resin composite material was decomposed into powder within 24 hours.

[0129] Example 11

[0130] Preparation of recyclable epoxy resin: 5g of benzil dioxime was added to 95g of TS190 epoxy resin and mixed thoroughly to produce the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed thoroughly to produce an epoxy resin mixture. The benzil dioxime content was 5% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. The epoxy resin mixture was heated in an oven at 30°C for 4 hours, then the temperature was increased to 70°C and continued to heat for 10 hours to produce the recyclable epoxy resin.

[0131] Degradation of recyclable epoxy resin: The recyclable epoxy resin prepared in this example was cut into small pieces of approximately 5 cm × 5 cm × 3 mm. The small pieces were then completely immersed in 1 mol / L glacial acetic acid and heated at 70°C. The recyclable epoxy resin was completely degraded within 16 hours.

[0132] Preparation of an epoxy resin composite: 5g of benzildioxime was added to 95g of TS190 epoxy resin and mixed evenly to prepare the epoxy resin portion. 28g of TS195 curing agent was then added to the epoxy resin portion and mixed evenly to prepare an epoxy resin mixture. The benzildioxime content was 5% by weight of the epoxy resin portion, and the weight ratio of the epoxy resin portion to the curing agent portion was 100:28. A four-layer glass fiber vacuum infusion platform was constructed. The epoxy resin mixture was introduced into the vacuum infusion platform and impregnated the glass fibers. The epoxy resin composite was then heated at 70°C for 10 hours to obtain the epoxy resin composite.

[0133] Degradation of epoxy resin composite material: The epoxy resin composite material prepared in this example was cut into small pieces of 5 cm × 5 cm × 3 mm, and then the small pieces were completely immersed in 0.5 mol / L glacial acetic acid and heated at 70°C. Part of the epoxy resin system in the epoxy resin composite material was decomposed into powder within 24 hours.

[0134] Comparative Example 1

[0135] Prepare epoxy resin blocks: Mix 100g of TS190 epoxy resin and 28g of TS195 curing agent. Heat the mixture in an oven at 30°C for 4 hours, then increase the temperature to 70°C and continue heating for 10 hours to obtain epoxy resin blocks.

[0136] Degradation of epoxy resin cured block: Cut the epoxy resin cured block into small pieces of about 5cm×5cm×3mm, then completely immerse the small piece in 0.5mol / L glacial acetic acid and heat at 70℃. After 24 hours, the small piece will crack into three parts with a length of 1-2cm.

[0137] Prepare the epoxy resin composite block: Mix 100g of TS190 epoxy resin and 28g of TS195 curing agent. Build a four-layer glass fiber vacuum infusion platform. The mixture is introduced into the vacuum infusion platform to impregnate the glass fibers. Heat at 70°C for 10 hours to obtain the 190 / 195 epoxy resin composite.

[0138] Degradation of epoxy resin composite cured block: Cut the epoxy resin composite cured block into small blocks of 5 cm × 5 cm × 3 mm, then completely immerse the small blocks in 0.5 mol / L glacial acetic acid and heat at 70°C. No powder will settle after 24 hours.

[0139] Specifically, the glacial acetic acid in the above-described embodiment is not diluted and can be used, but the effect of use is not promoted by glacial acetic acid after dilution, and volatility is larger, so it is necessary to note safety protection. At room temperature, solidified block is immersed in dilute acetic acid or Bu3P / DMF solution and can be degraded, but needs a long time (about one week) to be fully degraded. Heating can effectively accelerate degradation progress, and wherein 60-80 degrees Celsius is the preferred selection of the implementation conditions taking into account reaction rate and. In addition, the corresponding respective addition content of different types of swelling additives in the scope can reach identical degradation effect.

[0140] By standard ISO527-2, the maximum force, tensile strength, elastic modulus, elongation at break and tensile strength strain of the recyclable epoxy resin obtained by test embodiment one, embodiment six to embodiment eleven, and the epoxy resin cured block obtained by comparative example one are tested.Wherein the test speed is 2mm / min, and the average value, standard deviation and coefficient of variation of 6 valid data are taken.The maximum force, tensile strength, elastic modulus, elongation at break and tensile strength strain data of the recyclable epoxy resin obtained by embodiment six to embodiment eleven are close to the maximum force, tensile strength, elastic modulus, elongation at break and tensile strength strain data of the recyclable epoxy resin obtained by embodiment one respectively.The specific data of the maximum force, tensile strength, elastic modulus, elongation at break and tensile strength strain of the recyclable epoxy resin obtained by embodiment one are as shown in Table 1.

[0141] Table 1

[0142] The specific data of the maximum force, tensile strength, elastic modulus, elongation at break and tensile strength strain of the epoxy resin cured block in Comparative Example 1 are shown in Table 2.

[0143] Table 2

[0144] Comparing Table 1 and Table 2, it can be seen that the maximum force, tensile strength, and elastic modulus of the recyclable epoxy resin prepared in Example 1 are not much different from those of the epoxy resin cured block in Comparative Example 1. The elongation at break and tensile strength strain of the recyclable epoxy resin prepared in Example 1 are better than those of the epoxy resin cured block in Comparative Example 1. It can be seen that the swelling additive added in this application has no adverse effect on the main mechanical properties of the recyclable epoxy resin, and some properties are improved.

[0145] According to standard ISO178, the maximum bending force, flexural strength, flexural modulus and strain at maximum force of the recyclable epoxy resin obtained in Example 1, Example 6 to Example 11 and the epoxy resin cured block obtained in Comparative Example 1 are tested. Wherein the test speed is 2mm / min, the span is 64mm, and the average value, standard deviation and coefficient of variation of 6 valid data are taken. The maximum bending force, flexural strength, flexural modulus and strain at maximum force data of the recyclable epoxy resin obtained in Example 6 to Example 11 are respectively close to the maximum bending force, flexural strength, flexural modulus and strain at maximum force data of the recyclable epoxy resin obtained in Example 1. The specific data of the maximum bending force, flexural strength, flexural modulus and strain at maximum force of the recyclable epoxy resin obtained in Example 1 are as shown in Table 3.

[0146] Table 3

[0147] The specific data of the maximum bending force, bending strength and bending modulus of the epoxy resin cured block in Comparative Example 1 are shown in Table 4.

[0148] Table 4

[0149] By comparing Table 3 and Table 4, it can be seen that the maximum bending force, bending strength and bending modulus of the recyclable epoxy resin prepared in Example 1 are not much different from the maximum bending force, bending strength and bending modulus of the epoxy resin cured block in Comparative Example 1.

[0150] By standard ISO527-5:2009, the strength, modulus and strain of the recyclable epoxy resin composite material that test embodiment one, embodiment five to embodiment eleven make and the epoxy resin composite material cured block that comparative example one makes are tested.Wherein the test speed is 1.00mm / min, and the mean value, standard deviation and coefficient of variation of 6 valid data are taken.The strength, modulus and strain data of the recyclable epoxy resin composite material that embodiment five to embodiment eleven make are close to the strength, modulus and strain data of the recyclable epoxy resin composite material that embodiment one makes respectively.The specific data of the strength, modulus and strain of the recyclable epoxy resin composite material that embodiment one makes are as shown in Table 5.

[0151] Table 5

[0152] The specific data of strength, modulus and strain of the epoxy resin composite material cured block in Comparative Example 1 are shown in Table 6.

[0153] Table 6

[0154] Comparing Tables 5 and 6, it can be seen that the tensile strength of the recyclable epoxy resin composite material prepared in Example 1 is superior to that of the cured epoxy resin composite material block in Comparative Example 1. The modulus and strain of the recyclable epoxy resin composite material prepared in Example 1 are similar to those of the cured epoxy resin composite material block in Comparative Example 1. This shows that the swelling additive added in this application has no adverse effect on the main mechanical properties of the recyclable epoxy resin composite material and even improves some properties.

[0155] In summary, the present application adds micron-sized solid particles as swelling additives to the epoxy resin part to modify the existing epoxy resin system material. The swelling additive is always in powder state. The recyclable epoxy resin system material is friendly to the existing process and the production operation is simple. The mechanical properties of the prepared recyclable epoxy resin and composite materials remain largely unchanged. When encountering a degradation solvent, it swells and does not dissolve, causing cracks in the cured product. The solid powder and lumps generated by degradation are easy to separate, the degradation solvent can be reused, and the choice of swelling additives is also relatively wide.

[0156] While embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations of these embodiments are possible. However, it should be understood that such modifications and variations are within the scope and spirit of the invention as defined in the appended claims. Furthermore, the invention described herein is susceptible to other embodiments and may be practiced or implemented in a variety of ways.

Claims

1. A recyclable epoxy resin system material, characterized in that: Comprising an epoxy resin part and a curing agent part, wherein the weight ratio of the epoxy resin part to the curing agent part is 100:(20-105); The epoxy resin part is added with a swelling additive, and the content of the swelling additive is 0.0001-15wt% based on the weight percentage of the epoxy resin part. The swelling additive is micron-sized solid particles, and is always present in the recyclable epoxy resin system material and its cured product in a powder state, and undergoes a swelling reaction after encountering a degradation solvent.

2. The recyclable epoxy resin system material according to claim 1, characterized in that: The swelling additive is selected from one or more of amino acid, reversible covalent bond-containing and inorganic compound powder solids.

3. The recyclable epoxy resin system material according to claim 1, characterized in that: The swelling additive is selected from L-cystine, glyoxal bis(o-aminophenol), benzyl-2-naphthylamine, dibenzylhydrazine, N,N'-bis(2-aminobenzylidene)ethylenediamine, polyanilinehydrazine, N,N'-bis(5-hydroxysalicylidene)ethylenediamine, N,N'-diphenylformamidine, N,N'-bis(salicylidene)-1,2-propylenediamine, salicylaldehyde azine, N,N'-bis(salicylidene)ethylenediamine, benzyldioxime, ethylenediamine At least one of oxime, salicylaldehyde oxime, salicylaldehyde semicarbazone, N-phenylbenzamidine, 4'-ethoxybenzylidene-4-butylaniline, N-benzylidene aniline, calcium carbonate, DL-methionine, S-benzyl-L-cysteine, N-(4-methoxybenzylidene)-4-butylaniline, N-(4-methoxybenzylidene)aniline, N-benzylidene-p-toluidine, N-benzylidenemethylamine and trans-N-(2-pyridylmethylene)aniline.

4. The recyclable epoxy resin system material according to claim 3, characterized in that: The swelling additive is one or a mixture of L-cystine, calcium carbonate, DL-methionine, S-benzyl-L-cysteine, glyoxal bis(o-aminophenol) and benzil dioxime.

5. A recyclable epoxy resin, characterized in that: The recyclable epoxy resin system material according to any one of claims 1 to 4 is used and prepared by the following steps: S1, adding the swelling additive to the epoxy resin part and mixing them evenly; S2, mixing the epoxy resin part and the curing agent part obtained in the step S1 in proportion, and curing them to obtain the recyclable epoxy resin.

6. A method for recycling the recyclable epoxy resin as claimed in claim 5, characterized in that: The following steps are involved: T1, immersing the recyclable epoxy resin in a degradation solvent for degradation; The degradation solvent is at least one of water, diluted acid, alkaline solution, benzene, halogenated hydrocarbons, ethers and alcohols.

7. The method for recycling recyclable epoxy resin according to claim 6, characterized in that: The degradation solvent is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide and dimethyl sulfoxide.

8. The method for recycling recyclable epoxy resin according to claim 6, characterized in that: The degradation solvent is 0.1mol / L-1mol / L glacial acetic acid or 0.1mol / L-1mol / L Bu3P / DMF.

9. A recyclable epoxy resin composite material, characterized in that: The invention comprises reinforcing fibers and the recyclable epoxy resin system material as claimed in any one of claims 1 to 4.

10. The recyclable epoxy resin composite material according to claim 9, characterized in that: The reinforcing fibers are glass fibers or carbon fibers.

11. The recyclable epoxy resin composite material according to claim 9, characterized in that: The reinforcing fiber and the recyclable epoxy resin system material are prepared by a vacuum infusion method to obtain the recyclable epoxy resin composite material.

12. A method for recycling the recyclable epoxy resin composite material according to any one of claims 9 to 11, characterized in that: The following steps are involved: P1, cutting the recyclable epoxy resin composite material into blocks; P2, immersing the recyclable epoxy resin composite material cut into blocks in the step P1 in a degradation solvent for degradation; The degradation solvent is at least one of glacial acetic acid, Bu3P / DMF, water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, benzene, toluene, xylene, chlorobenzene, chloroform, dichloroethane, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, ethylene glycol, propanol, benzyl alcohol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, acetic anhydride, ethyl acetate, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, dimethylformamide, carbon disulfide and dimethyl sulfoxide.

13. The method for recycling the recyclable epoxy resin composite material according to claim 12, characterized in that: The degradation solvent is 0.1mol / L-1mol / L glacial acetic acid or 0.1mol / L-1mol / L Bu3P / DMF.

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