Room temperature recyclable epoxy resin and method of making the same

Abstract

The application discloses a room-temperature recyclable epoxy resin and a preparation method thereof. Specifically, the room-temperature recyclable epoxy resin of the application is composed of a base epoxy resin and amino phenylboronic acid; wherein the mass ratio of the base epoxy resin to the amino phenylboronic acid is 100:(1-50). The epoxy resin of the application has excellent mechanical properties and room-temperature alcoholysis recyclable performance, and the preparation process is simple.

Description

Technical Field

[0001] This invention relates to the field of epoxy resin technology, specifically, to a room-temperature recyclable epoxy resin and its preparation method. Background Technology

[0002] Epoxy resin is an important type of thermosetting polymer material. Due to its excellent mechanical properties, thermal stability, chemical corrosion resistance and good molding and processing performance, it is widely used in many fields such as wind power generation, electronics and electrical engineering, automobile manufacturing and construction.

[0003] However, the crosslinking network of traditional thermosetting epoxy resins is mainly composed of irreversible covalent bonds. Once cured, the material cannot be reprocessed or reshaped, making effective recycling difficult and resulting in resource waste and significant environmental pollution. To address the epoxy resin recycling challenge, dynamic covalent bonds have been introduced into the epoxy crosslinking network to develop recyclable epoxy resins. Existing dynamic covalent bonds include disulfide bonds, imine bonds, and ester bonds, but these resins suffer from insufficient mechanical strength, stringent recycling conditions, and environmental pollution caused by the use of large amounts of organic solvents. Furthermore, the recycling process can easily damage the resin structure, making regeneration difficult.

[0004] Dynamic borate ester bonds (BOCs) are considered ideal dynamic crosslinking units for constructing recyclable epoxy resins due to their rapid alcoholysis kinetics and mild triggering conditions. However, existing borate ester bond-based epoxy resin systems still face numerous challenges in their preparation, such as catalyst residue, difficulty in precisely controlling crosslinking density, and limited introduction of borate ester bonds, resulting in a trade-off between the material's mechanical properties and recyclability. Furthermore, existing processes are typically complex, and a simple, efficient, catalyst-free, and scalable technical solution has yet to be developed.

[0005] Therefore, there is an urgent need in the field for borate ester bond epoxy resin systems that do not require solvents, have simple preparation processes, and possess both high mechanical properties and room-temperature recyclability. Summary of the Invention

[0006] In view of the problems that traditional epoxy resins are not recyclable in the prior art, and that existing recyclable epoxy resins have problems such as harsh recycling conditions and difficulty in balancing mechanical properties and recyclability, the present invention provides a room temperature recyclable epoxy resin and its preparation method, namely, a dynamically crosslinked epoxy prepolymer of organoboron compounds and its preparation method.

[0007] In a first aspect of the invention, a room-temperature recyclable epoxy resin is provided, the epoxy resin being composed of a matrix epoxy resin and aminophenylboronic acid; The mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100:(1~50).

[0008] In a preferred embodiment, the mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100:(20~40).

[0009] In a preferred embodiment, the matrix epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, bisphenol S type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, phenoxy resin, or combinations thereof.

[0010] In a preferred embodiment, the aminophenylboronic acid is 2-aminophenylboronic acid, 3-aminophenylboronic acid, or 4-aminophenylboronic acid.

[0011] In another preferred embodiment, the aminophenylboronic acid is .

[0012] A second aspect of the present invention provides a method for preparing a room-temperature recyclable epoxy resin as described in the first aspect of the present invention, comprising the following steps: (1) Under the protection of an inert gas, the matrix epoxy resin and aminophenylboronic acid are mixed and stirred at 50~100℃ for 10~60 min to obtain an epoxy prepolymer containing borate ester bonds. (2) The epoxy prepolymer obtained in step (1) is cured at 120~200°C for 2~10 h to obtain the room temperature recyclable epoxy resin as described in the first aspect of the present invention.

[0013] In another preferred embodiment, the inert gas is selected from the group consisting of nitrogen, argon, or combinations thereof.

[0014] In another preferred embodiment, in step (1), the stirring temperature is 50~90℃, preferably 50~80℃, and more preferably 55~75℃.

[0015] In another preferred embodiment, in step (1), the stirring temperature is 60~80°C.

[0016] In another preferred embodiment, in step (1), the stirring time is 10 to 40 minutes, preferably 20 to 40 minutes, and more preferably 30 to 40 minutes.

[0017] In a preferred embodiment, the matrix epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, bisphenol S type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, phenoxy resin, or combinations thereof.

[0018] In another preferred embodiment, the aminophenylboronic acid is 2-aminophenylboronic acid, 3-aminophenylboronic acid, or 4-aminophenylboronic acid.

[0019] In another preferred embodiment, the aminophenylboronic acid is .

[0020] In a preferred embodiment, in step (1), the mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100: (1~50), preferably 100: (20~40).

[0021] In a preferred embodiment, in step (2), the curing is performed at 120~200°C for 4~8 h, preferably at 140~180°C for 4~8 h.

[0022] In another preferred embodiment, the curing is a gradient curing comprising the following steps: first curing at 120~160℃ for 1~4 h, and then curing at 140~180℃ for 1~6 h, provided that the second curing temperature is 5~25℃ higher than the first curing temperature; Preferably, the curing process involves first curing at 130-150℃ for 1-3 hours, and then curing at 150-170℃ for 2-6 hours, provided that the second curing temperature is 10-20℃ higher than the first curing temperature.

[0023] In another preferred embodiment, the second curing temperature is 10-20°C higher than the first curing temperature.

[0024] In another preferred embodiment, the curing is a gradient curing process including the following steps: first curing at 130~150℃ for 1~3 h, and then curing at 155~175℃ for 3~5 h; More preferably, the curing is first carried out at 135~145℃ for 1~3 h, and then at 155~165℃ for 3~5 h.

[0025] A third aspect of the present invention provides a method for recycling room-temperature recyclable epoxy resin as described in the first aspect of the present invention, the method comprising the following steps: adding a composite material obtained from room-temperature recyclable epoxy resin to an alcohol-based organic solvent, stirring at room temperature for 1 to 10 h to obtain a degraded resin, and vacuum drying the degraded resin at 30 to 80 °C for 1 to 10 h to obtain a recycled room-temperature recyclable epoxy resin. The room-temperature recyclable epoxy resin is either the room-temperature recyclable epoxy resin described in the first aspect of the present invention or the room-temperature recyclable epoxy resin prepared by the preparation method described in the second aspect of the present invention.

[0026] In another preferred embodiment, the mass-to-volume ratio of the room-temperature recyclable epoxy resin to the organic solvent is 1: (1~50), preferably 1: (1~20), more preferably 1: (1~10), and most preferably 1: (2~6).

[0027] In another preferred embodiment, the stirring time is 1 to 8 hours, preferably 1 to 5 hours, and more preferably 1 to 3 hours.

[0028] In another preferred embodiment, the vacuum drying is performed at 40-70 °C for 1-8 h, preferably at 50-70 °C for 1-5 h.

[0029] In a preferred embodiment, the alcoholic organic solvent is selected from the group consisting of methanol, ethanol, propanol, or combinations thereof.

[0030] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Detailed Implementation

[0031] Through long-term and in-depth research and extensive screening, the inventors have developed for the first time a borate ester bond-containing epoxy resin system that requires no solvent, has a simple preparation process, and possesses both high mechanical properties and room-temperature recyclability. By utilizing the ring-opening reaction between the amino and epoxy groups in the aminophenylboronic acid molecule, the hydroxyl content in the system is increased, thereby promoting the formation of borate ester bonds and increasing their crosslinking density, ultimately achieving a synergistic improvement in the material's mechanical properties and recyclability. The resin of this invention, after curing, can be completely depolymerized in an alcohol solvent at room temperature within several hours; the depolymerized resin can be recycled, and the regenerated resin retains the main properties of the original resin. Based on this, the inventors completed this invention.

[0032] The epoxy resin of the present invention The epoxy resin prepared in this invention uses dynamic borate ester (BOC) bonds as the core crosslinking structural unit. Through the ring-opening reaction of amino groups on epoxy groups, the hydroxyl content in the system is increased, thereby increasing the crosslinking sites in which boron hydroxyl groups participate in the formation.

[0033] The epoxy resin prepared by this invention possesses both excellent mechanical properties and room-temperature alcoholysis recyclability, and the preparation process is simple. The resin of this invention can achieve rapid depolymerization in alcohol solvents, and the depolymerized resin can be efficiently regenerated and reused, thereby realizing the closed-loop recycling of epoxy resin.

[0034] The materials obtained by this invention can be widely used in high-tech fields such as wind power generation, electronic packaging, and transportation.

[0035] The preparation method of epoxy resin of the present invention The preparation method of the present invention uses epoxy resin and aminophenylboronic acid as reaction raw materials. Under inert gas protection conditions and without the addition of an external catalyst, the reaction system is uniformly mixed and stirred for 10-40 min at 50-100°C to prepare an epoxy prepolymer rich in boronic acid ester dynamic covalent bonds. Subsequently, the prepolymer is cured by a stepped heating process to finally obtain a boronic acid ester bond-containing epoxy resin material with room temperature recyclability.

[0036] In a preferred embodiment, a method for preparing a room-temperature recyclable epoxy resin according to the present invention includes the following steps: (1) Add aminophenylboronic acid and epoxy resin to a four-necked flask, mix them uniformly in the system at 50~100℃ under nitrogen protection, and stir for 10~60min to obtain a boron ester bond epoxy prepolymer. (2) The epoxy prepolymer from step (1) is cured at 120℃~200℃ for 2~10h in a step-heating process to obtain a room-temperature recyclable epoxy resin containing borate ester bonds.

[0037] In a preferred embodiment, the matrix epoxy resin used is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, bisphenol S type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, phenoxy resin, or combinations thereof.

[0038] In a preferred embodiment, the aminophenylboronic acid has the following structural formula: In a preferred embodiment, in step (1), the mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100: (1~50), preferably 100: (20~40).

[0039] In a preferred embodiment, in step (2), the curing temperature rise process is curing at 100℃~200℃ for 2~10h, preferably at 140℃~180℃ for 4~8h.

[0040] The main advantages of this invention are: 1. The present invention provides a novel room-temperature recyclable epoxy resin preparation method. The preparation process is simple, with no catalyst involved throughout, thus avoiding the impact of catalyst residue on the performance of the epoxy resin. Furthermore, the reaction conditions are convenient and mild, requiring no complex monomer synthesis process, high-temperature and high-pressure equipment, making it easy to scale up for industrial production.

[0041] 2. The resin prepared by this invention is soluble in a variety of low-boiling-point solvents, which is beneficial for preparing various high-performance composite materials. The composite materials have both excellent mechanical properties and room-temperature recyclability, solving the problem of difficult recycling of traditional epoxy resins, realizing closed-loop recycling of epoxy resins, and reducing resource waste and environmental pollution.

[0042] 3. This invention uses aminophenylboronic acid as a functionalized crosslinking agent, fully leveraging the synergistic effect of its amino and boron hydroxyl groups. The amino group increases the hydroxyl content of the system through a low-temperature prepolymerization ring-opening reaction, while the boron hydroxyl group further forms dynamic borate ester bonds with the hydroxyl group. This allows hydroxyl generation and dynamic crosslinking to occur simultaneously, significantly increasing the borate ester bond density without the need for additional chain extenders or crosslinking agents. The resulting resin possesses high crosslinking density, excellent mechanical properties, and rapid room-temperature recyclability.

[0043] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, were generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, percentages and parts are weight percentages and parts by weight.

[0044] Comparative Example 1 1. Preparation of epoxy resin (1) Add 3g of 4,4'-diaminodiphenylmethane (DDM) and 10g of bisphenol A epoxy resin to a dry four-necked flask, and stir and react at 140°C for 1h under nitrogen protection to obtain resin prepolymer. (2) Pour the resin prepolymer obtained in step (1) into a polytetrafluoroethylene mold, cure at 140℃ / 2h+160℃ / 4h for 4h, cool and demold to obtain the cured resin.

[0045] 2. Preparation of epoxy resin composite materials Epoxy resin glass fiber prepreg with a resin content of 35% was prepared by solution impregnation. The prepreg was then stacked and placed in a vulcanizing machine, and molded at 120℃ / 2h + 140℃ / 2h + 160℃ / 2h to obtain an epoxy resin composite material.

[0046] The composite material does not contain reversible bonds and cannot be recycled at room temperature.

[0047] Comparative Example 2 1. Preparation of epoxy resin (1) Add 1g of 4,4'-diaminophenyl sulfone (DDS) and 10g of bisphenol A epoxy resin to a dry four-necked flask and stir at 150°C for 2h under nitrogen protection. (2) After the resin system in step (1) has cooled down, add 50g of tetrahydrofuran and 1.4g of phenylboronic acid, heat to 70℃ and stir for 3h to obtain epoxy resin prepolymer solution. Then remove the solvent by vacuum rotary evaporation to obtain resin prepolymer. (3) Pour the resin prepolymer obtained in step (2) into a polytetrafluoroethylene mold, cure at 140℃ / 2h+160℃ / 4h, cool and demold to obtain the cured resin.

[0048] 2. Preparation of epoxy resin composite materials (1) Epoxy resin glass fiber prepreg was prepared by solution impregnation, with a resin content of 35%. The prepreg was stacked and placed in a vulcanizing machine, and molded at 120℃ / 2h+140℃ / 2h+160℃ / 2h to obtain epoxy resin composite material.

[0049] 3. Recycling and Recompression of Epoxy Resin Composite Materials The composite material was placed in methanol and stirred at room temperature for 12 hours to obtain a methanol-degraded and stratified composite material. The stratified composite material was then soaked and rinsed with tetrahydrofuran to completely dissolve the degrading resin, thereby cleanly separating the resin from the glass fiber. The separated resin solution and glass fiber were vacuum dried in a vacuum oven at 60°C for 2 hours to obtain the recovered resin and recovered glass fiber.

[0050] 1g of phenylboronic acid needs to be added to the recycled resin to prepare glass fiber prepreg through solution impregnation before heavy-duty epoxy resin composite material can be obtained by compression molding using the same process.

[0051] Example 1 1. Preparation of room temperature recyclable epoxy resin (1) Add 2.4g of aminophenylboronic acid and 10g of bisphenol A epoxy resin to a dry four-necked flask and stir at 70°C for 40min under nitrogen protection to obtain a boron ester bond epoxy prepolymer. (2) Pour the resin obtained in step (1) into a polytetrafluoroethylene mold, cure at 140℃ / 2h+160℃ / 4h, cool and demold to obtain a room temperature recyclable epoxy resin curing material containing borate ester bonds.

[0052] 2. Recycling of room temperature recyclable epoxy resin 3g of the borate ester bond-containing room temperature recyclable epoxy resin cured product obtained in step (2) was placed in 10ml of methanol and stirred at room temperature for 2h to obtain a yellow soft degradable resin that swells in methanol. The degradable resin was then placed in a vacuum oven at 50℃ and vacuum dried for 2h to obtain the recycled resin.

[0053] 3. Preparation of epoxy resin composite materials A borate ester bond epoxy resin glass fiber prepreg with a resin content of 35% was prepared by solution impregnation. The prepreg was then stacked and placed in a vulcanizing machine, and molded at 120℃ / 2h+140℃ / 2h+160℃ / 2h to obtain a borate ester bond epoxy resin composite material.

[0054] 4. Recycling and Recompression of Epoxy Resin Composite Materials The boron ester bond epoxy resin composite material was placed in methanol and stirred at room temperature for 4 hours to obtain a methanol-degraded and layered composite material. The layered composite material was soaked and rinsed with tetrahydrofuran to completely dissolve the degraded resin, thereby cleanly separating the resin from the glass fiber. The separated resin solution and glass fiber were vacuum dried in a vacuum oven at 60°C for 2 hours to obtain the recovered resin and recovered glass fiber.

[0055] The obtained recycled resin and glass fiber are directly molded using the same process to obtain a recyclable epoxy resin composite material after heavy compression.

[0056] Example 2 1. Preparation of room temperature recyclable epoxy resin (1) Add 3.5g of aminophenylboronic acid and 10g of bisphenol S-type epoxy resin to a dry four-necked flask and stir at 60°C for 30min under nitrogen protection to obtain a boron ester bond epoxy prepolymer. (2) Pour the resin obtained in step (1) into a polytetrafluoroethylene mold, cure at 140℃ / 2h+160℃ / 4h, cool and demold to obtain a room temperature recyclable epoxy resin curing material containing borate ester bonds.

[0057] 2. Recycling of room temperature recyclable epoxy resin 3g of the borate ester bond-containing room temperature recyclable epoxy resin cured product obtained in step (2) was placed in 10ml of methanol and stirred at room temperature for 2h to obtain a yellow soft degradable resin that swells in methanol. The degradable resin was then placed in a vacuum oven at 50℃ and vacuum dried for 2h to obtain the recycled resin.

[0058] 3. Preparation of epoxy resin composite materials A borate ester bond epoxy resin glass fiber prepreg with a resin content of 35% was prepared by solution impregnation. The prepreg was then stacked and placed in a vulcanizing machine, and molded at 120℃ / 2h+140℃ / 2h+160℃ / 2h to obtain a borate ester bond epoxy resin composite material.

[0059] 4. Recycling and Recompression of Epoxy Resin Composite Materials The boron ester bond epoxy resin composite material was placed in methanol and stirred at room temperature for 2 hours to obtain a methanol-degraded and layered composite material. The layered composite material was soaked and rinsed with ethyl acetate to completely dissolve the degraded resin, thereby cleanly separating the resin from the glass fiber. The separated resin solution and glass fiber are vacuum dried in a vacuum oven at 70°C for 2 hours to obtain recycled resin and recycled glass fiber.

[0060] The obtained recycled resin and glass fiber are directly molded using the same process to obtain a recyclable epoxy resin composite material after heavy compression.

[0061] Example 3 1. Preparation of room temperature recyclable epoxy resin (1) Add 2.7g of aminophenylboronic acid and 10g of bisphenol F epoxy resin to a dry four-necked flask and stir at 70°C for 40min under nitrogen protection to obtain a boron ester bond epoxy prepolymer. (2) Pour the resin obtained in step (1) into a polytetrafluoroethylene mold, cure at 140℃ / 2h+160℃ / 4h, cool and demold to obtain a room temperature recyclable epoxy resin curing material containing borate ester bonds.

[0062] 2. Recycling of room temperature recyclable epoxy resin 3g of the borate ester bond-containing room temperature recyclable epoxy resin cured product obtained in step (2) was placed in 10ml of ethanol and stirred at room temperature for 2h to obtain a yellow soft degradable resin that swells in ethanol. The degradable resin was then placed in a vacuum oven at 60℃ and vacuum dried for 2h to obtain the recycled resin.

[0063] 3. Preparation of epoxy resin composite materials A borate ester bond epoxy resin glass fiber prepreg with a resin content of 35% was prepared by solution impregnation. The prepreg was then stacked and placed in a vulcanizing machine, and molded at 120℃ / 2h+140℃ / 2h+160℃ / 2h to obtain a borate ester bond epoxy resin composite material.

[0064] 4. Recycling and Recompression of Epoxy Resin Composite Materials The boron ester bond epoxy resin composite material was placed in methanol and stirred at room temperature for 6 hours to obtain the ethanol-degraded and layered composite material. The layered composite material was soaked and rinsed with methyl ethyl ketone to completely dissolve the degraded resin, thereby cleanly separating the resin from the glass fiber. The separated resin solution and glass fiber are vacuum dried in a vacuum oven at 65°C for 2 hours to obtain recycled resin and recycled glass fiber.

[0065] The obtained recycled resin and glass fiber are directly molded using the same process to obtain a recyclable epoxy resin composite material after heavy compression.

[0066] Experimental Example 1 The cured resin was subjected to DSC and TGA tests in a nitrogen atmosphere at a heating rate of 10℃ / min to obtain the glass transition temperature and the thermal decomposition temperature with 5% mass loss (T). d5 The mass retention rates at 800℃ and 800℃ are shown in Table 1 below.

[0067] Table 1. Glass transition temperature, Tg of cured resins d5 and 800℃ mass retention rate Experimental results show that the epoxy resin of the present invention participates in curing only through aminophenylboronic acid, forming a dense three-dimensional cross-linked network, resulting in excellent curing quality, higher glass transition temperature, and high thermal stability.

[0068] Experiment Example 2 The mechanical properties of the above composite materials were tested, as shown in Table 2 below.

[0069] Table 2. Mechanical properties of composite materials Experimental results show that the composite material prepared by the epoxy resin of this invention is a structural material with high load-bearing capacity, resistance to deformation and fracture, stable interlayer structure, and excellent overall mechanical properties, exhibiting excellent mechanical properties and significantly improving the interfacial bonding ability between resin and fiber.

[0070] Furthermore, when phenylboronic acid is used as a curing agent (Comparative Example 2), additional phenylboronic acid needs to be added after recycling before it can be subjected to heavy compression. However, the resin using aminophenylboronic acid in this invention can be directly subjected to heavy compression after green recycling at room temperature to obtain composite materials, and the mechanical property retention rate exceeds 90%.

[0071] All documents mentioned in this invention are incorporated herein by reference as if each document were individually incorporated by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A room-temperature recyclable epoxy resin, characterized in that, The epoxy resin is composed of a matrix epoxy resin and aminophenylboronic acid; The mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100:(1~50).

2. The room-temperature recyclable epoxy resin as described in claim 1, characterized in that, The mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100:(20~40).

3. The room-temperature recyclable epoxy resin as described in claim 1, characterized in that, The matrix epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, bisphenol S type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, phenoxy resin, or combinations thereof.

4. The room-temperature recyclable epoxy resin as described in claim 1, characterized in that, The aminophenylboronic acid is 2-aminophenylboronic acid, 3-aminophenylboronic acid, or 4-aminophenylboronic acid.

5. A method for preparing a room-temperature recyclable epoxy resin as described in claim 1, characterized in that, Includes the following steps: (1) Under the protection of an inert gas, the matrix epoxy resin and aminophenylboronic acid are mixed and stirred at 50~100℃ for 10~60min to obtain an epoxy prepolymer containing borate ester bonds; (2) The epoxy prepolymer obtained in step (1) is cured at 120~200℃ for 2~10 h to obtain the room temperature recyclable epoxy resin as described in claim 1.

6. The preparation method according to claim 5, characterized in that, The matrix epoxy resin is selected from the group consisting of bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenolic type epoxy resin, bisphenol S type epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, phenoxy resin, or combinations thereof.

7. The preparation method according to claim 5, characterized in that, In step (1), the mass ratio of the matrix epoxy resin to aminophenylboronic acid is 100: (1~50), preferably 100: (20~40).

8. The preparation method according to claim 5, characterized in that, In step (2), the curing is performed at 120~200℃ for 4~8 h, preferably at 140~180℃ for 4~8 h.

9. A method for recycling the room-temperature recyclable epoxy resin as described in claim 1, characterized in that, The method includes the following steps: adding the composite material made from room temperature recyclable epoxy resin to an alcohol organic solvent, stirring at room temperature for 1 to 10 h to obtain a degraded resin, and vacuum drying the degraded resin at 30 to 80 °C for 1 to 10 h to obtain a recycled room temperature recyclable epoxy resin. Wherein, the room temperature recyclable epoxy resin is the room temperature recyclable epoxy resin as described in claim 1 or the room temperature recyclable epoxy resin prepared by the preparation method as described in claim 5.

10. The preparation method according to claim 9, characterized in that, The alcoholic organic solvent is selected from the group consisting of methanol, ethanol, propanol, or combinations thereof.

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