Degradable epoxy resin composite material with adjustable curing speed as well as preparation method and mild total recycling method thereof

Abstract

The invention relates to a degradable epoxy resin composite material with an adjustable curing speed, and a preparation method and a mild total recycling method thereof. Existing degradable epoxy resin has the problems of high cost, harsh degradation conditions and the like, and is difficult to meet the requirements of different application scenes on curing speed and temperature at the same time. The invention provides an epoxy resin composite material which comprises curing agent components (an epoxy resin amine curing agent and an ester-containing polythiol curing agent) and epoxy resin components (glycidyl ether epoxy resin, glycidyl amine epoxy resin and glycidyl ester epoxy resin). The cured composite material can be fully recycled through catalytic degradation under mild conditions by using a lewis acid and an amino group breaking ester bond mechanism, and the degradation product can be directly used as a curing agent, a toughening agent and a chain extender. The epoxy resin composite material disclosed by the invention not only has adjustable curing speed and high use performance, but also realizes environmental friendliness and resource recycling, and provides a new solution for sustainable development of epoxy resin.

Description

Technical Field

[0001] The present invention belongs to the technical field of degradable epoxy resins, and particularly relates to a degradable epoxy resin composite with adjustable curing speed, its preparation method, and a mild full recycling method. Background Art

[0002] Traditional epoxy resins are widely used in many fields due to their excellent mechanical properties and chemical stability. However, these properties also make them difficult to degrade in the natural environment, thus causing long-term pollution and burden to the environment. With the continuous improvement of environmental awareness and the deepening of the concept of sustainable development, the degradability of epoxy resins has become particularly important. Therefore, the development of degradable epoxy resin composites has become an important topic in the current research field of polymer materials. At present, although there have been studies dedicated to developing degradable epoxy resin materials, there are still many problems in the existing technologies. For example, although dynamic bond epoxy resins have certain degradability, they are expensive and have poor processability, making it difficult to be applied on a large scale. In addition, although epoxy resins containing ester groups can theoretically be degraded through alkaline hydrolysis, alcoholysis, and aminolysis, in actual operation, their fracture conditions are extremely harsh, usually requiring an environment of strong acids, strong bases, and high temperatures (usually above 120°C). For example, CN115536615B discloses a bio-based epoxy resin, and a series of compounds containing both multi-carboxyl and double-bond structures are obtained through esterification reaction, and based on this, a series of bio-based epoxy resin precursors containing ester groups and double-bond structures are obtained, and the degradation is achieved by the hydrolysis reaction of the ester bond under strong base conditions. This not only increases the cost of degradation and recycling but also inevitably forms secondary pollution, limiting its feasibility in practical applications. Although there have been studies attempting to solve the above problems through the formulation design and degradation methods of composites, there are still many technical challenges and no widespread application breakthroughs have been achieved.

[0003] Meanwhile, for different application fields, there are strict requirements for the curing speed and curing temperature of epoxy resins. For example, in the vacuum infusion process, a relatively long gel time (100 - 200 minutes) is usually required to ensure the uniform filling and curing effect of the material; while for application scenarios such as maintenance resins or adhesives, rapid curing at room temperature is required to improve construction efficiency and usability. However, the current epoxy resin composites still have great limitations in the regulation of curing speed and curing temperature, and it is difficult to meet the requirements of multiple application scenarios simultaneously. Therefore, it is urgent to optimize the composition design of epoxy resin composites to achieve flexible regulation of curing speed and curing temperature, while taking into account the degradability and environmental friendliness of the materials. Summary of the Invention

[0004] The object of the present invention is to solve the problems that existing epoxy resins are difficult to degrade, and there are still great limitations in the regulation of the curing speed and curing temperature of composite materials. A degradable epoxy resin composite material with adjustable curing speed and its preparation and mild full recycling method are provided, which can meet the requirements of low viscosity, adjustable curing speed and high service performance of epoxy resins, and the recycling reaction conditions are mild, and the full recycling of epoxy resins and reinforcements can be realized.

[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A degradable epoxy resin composite material with adjustable curing speed, the composite material includes a curing agent component, an epoxy resin component, a curing accelerator and a toughening agent; the molar ratio of epoxy groups to active hydrogen in the curing agent is 1:1 - 1.2; the curing accelerator accounts for 0wt% - 5wt% of the epoxy resin composite material, and the toughening agent accounts for 0wt% - 20wt% of the epoxy resin composite material; The curing agent component is an epoxy resin amine curing agent and an ester group-containing polythiol curing agent, and the ester group-containing polythiol curing agent accounts for 0.1wt% - 70wt% of the curing agent component; the epoxy resin amine curing agent accounts for 30wt% - 99.9wt% of the curing agent component; The ester group-containing polythiol curing agent is selected from one or more of the following, and has the following general structural formula:

[0006] R 1 and R 2 are one or more of an aliphatic carbon chain of C1 - C18, a benzene ring and its derivatives, and a heterocyclic structure containing oxygen, nitrogen, sulfur, phosphorus or silicon elements and its derivatives; The epoxy resin amine curing agent is one or more of isophorone diamine, 4,4 - diamino dicyclohexylmethane, 3,3'-dimethyl - 4,4 - diamino dicyclohexylmethane, menthane diamine, hydrogenated diaminodiphenylmethane, N - aminoethyl piperazine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diaminodiphenylmethane, diaminodiphenyl sulfone, m - xylylenediamine, polyetheramine D230, polyetheramine T403, dicyandiamide; The epoxy resin component includes glycidyl ether epoxy resins, glycidyl amine epoxy resins, glycidyl ester epoxy resins. Among them, glycidyl ether epoxy resins and glycidyl amine epoxy resins account for 12wt% - 78wt% of the epoxy resin component; glycidyl ester epoxy resins account for 22wt% - 88wt% of the epoxy resin component.

[0007] Further, the glycidyl ether epoxy resin is one or more of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, tetrabromobisphenol A diglycidyl ether, hydrogenated bisphenol A epoxy resin, linear phenolic epoxy resin, o-cresol novolac epoxy resin, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, resorcinol diglycidyl ether, naphthol novolac epoxy resin, biphenyl diglycidyl ether, alicyclic glycidyl ether, cyclohexanedimethanol diglycidyl ether, C12-C14 fatty alcohol glycidyl ether; The glycidylamine epoxy resin is one or more of 4,4'-diaminodiphenylmethane epoxy resin, triglycidyl p-aminophenol, tetraglycidyl m-xylenediamine, triglycidyl carbamate, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, triglycidyl isocyanurate; The glycidyl ester epoxy resin is one or more of diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl tetrahydrophthalate, diglycidyl methyltetrahydrophthalate, diglycidyl endomethylenetetrahydrophthalate, diglycidyl adipate, triglycidyl trimellitate, tetraglycidyl pyromellitate, soybean oil-based glycidyl ester;

[0008] Further, the curing accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)benzene, 1,8-diazabicyclo[5.4.0]-7-undecene, benzyldimethylamine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-mercaptobenzothiazole, metal acetylacetonate; The toughening agent is one or several of inorganic nanoparticles, polyether polyol, polysulfide rubber, PU prepolymer.

[0009] Further, the ester group-containing polythiol curing agent is one or more of pentaerythritol tetra(3-mercaptopropionate), dipentaerythritol hexa(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), ethylene glycol bis(3-mercaptopropionate), polyethylene glycol bis(3-mercaptopropionate), polypropylene glycol bis(3-mercaptopropionate), terephthalic acid bis(2-mercaptoethyl ester), glycerol tri(3-mercaptopropionate), adipic acid bis(2-mercaptoethyl ester);

[0010] Further, the composite material further includes a reinforcing body and auxiliary materials; The reinforcing agent is at least one of carbon fiber, glass fiber, natural fiber, chemical fiber, fabric made of fiber material, nano-carbon material, boron nitride nano-material, metal nano-particle, metal oxide nano-particle, and organic nano-particle, accounting for 50wt% - 65wt% of the total mass of the composite material; The auxiliary material is at least one of accelerator, diluent, plasticizer, toughening agent, thickening agent, coupling agent, defoamer, leveling agent, ultraviolet absorber, antioxidant, brightening agent, fluorescent reagent, pigment, and filler, accounting for 0.1wt% - 2wt% of the total mass of the composite material.

[0011] A preparation method of the above-mentioned degradable and curable speed-adjustable epoxy resin composite material is to take various raw materials according to the raw material contents and mix them, and cure at 25 - 100 °C for 1 - 24 h.

[0012] A mild full recycling method of the above-mentioned degradable and curable speed-adjustable epoxy resin composite material, the method is: soaking the degradable and curable speed-adjustable epoxy resin composite material in a catalytic degradation solution, and carrying out a catalytic bond-breaking reaction at 40 - 100 °C for 1 - 100 h to obtain a homogeneous degradation mixed solution; the reinforcing material can be recovered without damage after filtration, washing, and drying; the homogeneous degradation mixed solution can be directly used as a curing agent, toughening agent, or chain extender for epoxy resin or polyurethane without purification and separation.

[0013] Furthermore, the catalytic degradation solution includes a mixture of Lewis acid catalyst, amine compound, alcohol compound, and alkanolamine compound; the mass ratio of the Lewis acid catalyst is 0.1% - 30%, the mass ratio of the amine compound is 0% - 99%, the mass ratio of the alcohol compound is 0% - 99%, and the mass ratio of the alkanolamine compound is 0% - 99%.

[0014] Furthermore, the Lewis acid catalyst is one or more of aluminum trichloride, iron trichloride, titanium tetrachloride, boron trifluoride, boron trichloride, zinc chloride, trimethylaluminum, diethylzinc, triphenylboron, scandium trifluoromethanesulfonate, ytterbium trifluoromethanesulfonate, and aluminum chloride-imidazolium salt; The amine compound is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, butanediamine, hexanediamine, isophoronediamine, oleylamine, isopropylamine, tert-butylamine, benzylamine, cyclohexylamine, allylamine, and pyrrolidinemine; The alcohol compound is one or more of methanol, ethanol, isopropanol, butanol, cyclohexanol, glycerol, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, pentaerythritol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, polytetrahydrofuran diol, polypropylene glycol, castor oil-based diol, and polycarbonate diol; The alkanolamine compound is one or more of ethanolamine, diethanolamine, isopropanolamine, aminomethyl propanol, hydroxyethyl ethylenediamine, diethylene glycol amine, 1-amino-2-propanol, 1-amino-2-butanol, phenylethanolamine, 2-amino-2-methyl-1-propanol, and 2-amino-1-butanol.

[0015] The beneficial effects of the present invention compared with the prior art are as follows: (1) The present invention uses an ester group-containing polythiol curing agent as a functional curing agent with degradability and adjustable curing speed. After reacting with epoxy resin, the introduced ester group can be dissociated under the action of amine compounds, alcohol compounds, and alkanolamine compounds, endowing degradation and recycling performance.

[0016] (2) The mercapto group of the ester group-containing polythiol curing agent has high activity and can cure epoxy resin at room temperature. By adjusting the proportion of the ester group-containing polythiol curing agent, the curing speed of the epoxy resin composite can be controlled. The epoxy resin composite obtained by compounding with commercial epoxy resin and curing agent has low viscosity, adjustable reaction speed, and high glass transition temperature of the cured product, and can meet the process performance and service performance requirements for the production and use of existing wind turbine blades and maintenance resins.

[0017] (3) The supporting mild full recycling method provided by the present invention, through the synergistic effect of Lewis acid-catalyzed C-N bond cleavage and ester group dissociation reaction, reduces the catalytic degradation temperature to below 100 °C under normal pressure. The degradation conditions are mild, and the degradation process is green without any waste discharge. The recovered reinforcing material can be reused after separation, washing, and drying, and the resin degradation product can be directly used as a curing agent, toughening agent, or chain extender for epoxy resin or polyurethane without any purification and separation. Specific Embodiments

[0018] The technical solutions of the present invention will be further described below in conjunction with the embodiments, but are not limited thereto. Any modification or equivalent replacement of the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention shall be covered by the protection scope of the present invention. Example 1

[0019] Degradable and adjustable curing speed epoxy resin composite 1: Among them, the epoxy resin components are 70 parts by mass of bisphenol A diglycidyl ether epoxy resin and 30 parts by mass of diethyl adipate diglycidyl ester, and the curing agent components are 29 parts by mass of pentaerythritol tetra(3-mercaptopropionate), 1 part by mass of 2,4,6-tris(dimethylaminomethyl)benzene, and 70 parts by mass of 4,4-diaminodicyclohexylmethane.

[0020] Preparation of the cured product of the degradable and curable rate - adjustable epoxy resin 1: Take the above - mentioned epoxy resin components and curing agent components and mix them evenly according to a mass ratio of 100:37. After degassing under vacuum, pour them into a metal mold, and cure at room temperature for 24 h or at 60 °C for 8 h to obtain the epoxy resin casting body.

[0021] Degradation and recycling: Prepare the degradation solution by dissolving 1.5 g of zinc chloride and 6.5 g of ethanolamine in 100 mL of tetrahydrofuran. Take 5 g of the above - prepared epoxy resin, completely immerse it in the degradation solution, seal the system and heat it to 80 °C, and continuously stir for 12 h. The resin is completely degraded and dissolved in the degradation solution.

[0022] Table 1 Basic properties of the degradable and curable rate - adjustable epoxy resin casting body

[0023] Preparation of the degradable and curable rate - adjustable epoxy resin 1 composite material: Prepare the composite material by the vacuum infusion method. Prepare an appropriate amount of the above - prepared epoxy resin composite material, keep it at 30 °C for heat preservation, degas under vacuum and then pour it into a prepared vacuum bag with carbon fiber fabric, so that the resin is fully infiltrated. Stop the infusion after ensuring that there are no bubbles in the system, and cure at 60 °C for 8 h to obtain the fiber - reinforced composite material.

[0024] Degradation and recycling of the composite material: Prepare the degradation solution by dissolving 1.5 g of zinc chloride and 6.5 g of ethanolamine in 100 mL of tetrahydrofuran. Take about 8 g of the above - prepared composite material, completely immerse it in the degradation solution, seal the system and heat it to 80 °C, and continuously stir for 12 h. The resin is completely degraded and dissolved in the degradation solution. Take out the carbon fiber fabric and ultrasonically clean it with dichloromethane and ethanol respectively to obtain the carbon fiber fabric recovered without damage. Example 2

[0025] Degradable and curable rate - adjustable epoxy resin composite material 2: Among them, the epoxy resin components are 50 parts by mass of 4,4'-diaminodiphenylmethane epoxy resin and 50 parts by mass of bis - glycidyl - tetrahydrophthalate respectively, and the curing agent components are 15 parts by mass of pentaerythritol tetra(3 - mercaptopropionate) and 85 parts by mass of m - xylylenediamine respectively.

[0026] Preparation of the degradable and curable rate - adjustable epoxy resin 2: Take the above - mentioned epoxy resin components and curing agent components and mix them evenly according to a mass ratio of 100:28. After degassing under vacuum, pour them into a metal mold, and cure at 80 °C for 12 h to obtain the epoxy resin casting body.

[0027] Table 2 Basic properties of the degradable and curable rate - adjustable epoxy resin 2

[0028] Degradation and recycling of degradable and adjustable-curing-rate epoxy resin 2: Prepare a degradation solution by mixing 1 g of ferric chloride and 8 g of ethylenediamine. Take 5 g of the above-prepared epoxy resin, completely immerse it in the degradation solution, seal the system and heat it to 100 °C, and continuously stir for 8 h. The resin is completely degraded and dissolved in the degradation solution.

[0029] Preparation of degradable and adjustable-curing-rate epoxy resin 2 composite material: The composite material is prepared by the vacuum infusion method. Prepare an appropriate amount of the above-prepared epoxy resin composite, keep it at 30 °C, vacuum degas it, and then introduce it into a prepared vacuum bag with carbon fiber fabric, allowing the resin to fully infiltrate. Stop the infusion after ensuring that there are no bubbles in the system, heat it to 80 °C and cure for 12 h to obtain the fiber-reinforced composite material.

[0030] Degradation and recycling of the composite material: Prepare a degradation solution by mixing 1 g of ferric chloride and 8 g of ethylenediamine. Take about 8 g of the above-prepared composite material, completely immerse it in the degradation solution, seal the system and heat it to 100 °C, and continuously stir for 8 h. The resin is completely degraded and dissolved in the degradation solution. Take out the carbon fiber fabric and ultrasonically clean it with dichloromethane and ethanol respectively to obtain the carbon fiber fabric recovered without damage.

[0031] Comparative example 1: Epoxy resin composite material for comparative example: Among them, the epoxy resin component is 100 parts by mass of E51 epoxy resin, and the curing agent component is 100 parts by mass of m-xylenediamine.

[0032] Preparation of epoxy resin for comparative example: Take the above epoxy resin component and curing agent component and mix them evenly according to a mass ratio of 100:15, vacuum degas it, and then pour it into a metal mold, and cure it at 80 °C for 12 h to obtain an epoxy resin casting.

[0033] Table 3 Properties of epoxy resin for comparative example

[0034] Degradation and recycling of epoxy resin for comparative example: Prepare a degradation solution by mixing 1 g of ferric chloride and 8 g of ethylenediamine. Take 5 g of the above-prepared epoxy resin, completely immerse it in the degradation solution, seal the system and heat it to 100 °C, and continuously stir for 8 h. The resin only shows an obvious swelling phenomenon and fails to degrade and dissolve in the degradation solution.

[0035] By comparing Table 1, Table 2 and Table 3, it can be seen that the mechanical properties and thermal stability of the resin provided in the embodiments of the present invention are comparable to those of currently commercial epoxy resins, which can meet most application requirements. However, in terms of degradability, the resin provided in the embodiments of the present invention can be rapidly degraded under mild conditions below 100 °C and completely dissolved in the solution, which helps to recover the carbon fiber in the composite material without damage and realize the recycling and reuse of the recycled product. However, due to its stable three-dimensional structure, the resin in the comparative example fails to degrade under comparable conditions. It is proved that the epoxy resin system prepared by the method provided by the present invention has excellent thermodynamic properties and degradability.

Claims

1. A degradable epoxy resin composite with adjustable curing speed, characterized in that: The composite material comprises a curing agent component, an epoxy resin component, a curing accelerator and a toughening agent; the molar ratio of the epoxy group to the active hydrogen in the curing agent is 1:1-1.2; the curing accelerator accounts for 0wt%-5wt% of the epoxy resin composite material, and the toughening agent accounts for 0wt%-20wt% of the epoxy resin composite material; The curing agent component comprises an epoxy resin amine curing agent and an ester-containing polythiol curing agent, wherein the ester-containing polythiol curing agent accounts for 0.1wt%-70wt% of the curing agent component; the epoxy resin amine curing agent accounts for 30wt%-99.9wt% of the curing agent component; The ester-containing polythiol curing agent is selected from one or more and has the following general structural formula: R1 and R2 are one or more structures selected from a C1-C18 aliphatic carbon chain, a benzene ring and its derivatives, and a heterocyclic structure containing oxygen, nitrogen, sulfur, phosphorus or silicon and its derivatives; The epoxy resin amine curing agent is one or more of isophoronediamine, 4,4-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4-diaminodicyclohexylmethane, methylparaben, hydrogenated diaminodiphenylmethane, N-aminoethylpiperazine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diaminodiphenylmethane, diaminodiphenylsulfone, meta-xylylenediamine, polyetheramine D230, polyetheramine T403, and dicyandiamide; The epoxy resin component includes glycidyl ether epoxy resin, glycidyl amine epoxy resin and glycidyl ester epoxy resin, wherein glycidyl ether epoxy resin and glycidyl amine epoxy resin account for 12wt%-78wt% of the epoxy resin component; glycidyl ester epoxy resin accounts for 22wt%-88wt% of the epoxy resin component.

2. The degradable epoxy resin composite material with adjustable curing speed according to claim 1, characterized in that: The glycidyl ether epoxy resin is one or more of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, tetrabromobisphenol A diglycidyl ether, hydrogenated bisphenol A epoxy resin, novolac epoxy resin, o-cresol formaldehyde epoxy resin, neopentyl glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, resorcinol diglycidyl ether, naphthol formaldehyde epoxy resin, biphenyl diglycidyl ether, alicyclic glycidyl ether, cyclohexanedimethanol diglycidyl ether, and C12-C14 fatty alcohol glycidyl ether; The glycidylamine epoxy resin is one or more of 4,4'-diaminodiphenylmethane epoxy resin, triglycidyl p-aminophenol, tetraglycidyl m-phenylenediamine, triglycidyl carbamate, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, and triglycidyl triisocyanate; The glycidyl ester epoxy resin is one or more of diglycidyl phthalate, diglycidyl hexahydrophthalate, diglycidyl terephthalate, diglycidyl isophthalate, diglycidyl tetrahydrophthalate, diglycidyl methyltetrahydrophthalate, diglycidyl endometriyltetrahydrophthalate, diglycidyl adipate, triglycidyl trimellitate, tetraglycidyl pyromellitate, and soybean oil-based glycidyl ester.

3. The biodegradable epoxy resin composite with adjustable curing speed according to claim 1, characterized in that: The curing accelerator is one or more of 2,4,6-tris(dimethylaminomethyl)benzene, 1,8-diazabicyclo(5,4,0)-7-undecene, benzyldimethylamine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 2-mercaptobenzothiazole, and acetylacetone metal salt; The toughening agent is one or more of inorganic nanoparticles, polyether polyols, polysulfide rubber, and PU prepolymer.

4. The degradable epoxy resin composite material with adjustable curing speed according to claim 1, characterized in that: The ester-containing polythiol curing agent is one or more of pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexa (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate), bis (3-mercaptopropionic acid) ethylene glycol, polyethylene glycol di (3-mercaptopropionate), polypropylene glycol di (3-mercaptopropionate), terephthalic acid di (2-mercaptoethyl ester), glycerol tris (3-mercaptopropionate), and adipate di (2-mercaptoethyl ester).

5. The biodegradable epoxy resin composite with adjustable curing speed according to claim 1, characterized in that: The composite material also includes reinforcement and auxiliary materials; The reinforcement is at least one of carbon fiber, glass fiber, natural fiber, chemical fiber and fabric made of fiber material, nano carbon material, boron nitride nano material, metal nano particles, metal oxide nano particles and organic nano particles, accounting for 50wt%-65wt% of the total weight of the composite material; The auxiliary material is at least one of accelerator, diluent, plasticizer, toughener, thickener, coupling agent, defoamer, leveling agent, UV absorber, antioxidant, brightener, fluorescent agent, pigment and filler, accounting for 0.1wt%-2wt% of the total mass of the composite material.

6. A method for preparing the degradable epoxy resin composite with adjustable curing speed according to any one of claims 1 to 5, characterized in that: Take various raw materials according to their content and mix them, and cure them at 25~100℃ for 1~24 hours.

7. A method for gentle full recycling of the degradable epoxy resin composite material with adjustable curing speed according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: immersing a degradable epoxy resin composite material with adjustable curing speed in a catalytic degradation liquid, carrying out a catalytic bond breaking reaction at 40-100° C. for 1-100 h, and obtaining a homogeneous degradation mixed solution; the reinforcing material can be recovered losslessly after filtering, cleaning, and drying; and the homogeneous degradation mixed solution can be directly used as a curing agent, toughening agent, and chain extender for epoxy resin or polyurethane without purification and separation.

8. The method for gentle full recycling of a degradable epoxy resin composite with adjustable curing speed according to claim 7, characterized in that: The catalytic degradation liquid comprises a mixture of Lewis acid catalyst, amine compounds, alcohol compounds and alcohol amine compounds; the mass proportion of the Lewis acid catalyst is 0.1%-30%, the mass proportion of the amine compound is 0%-99%, the mass proportion of the alcohol compound is 0%-99%, and the mass proportion of the alcohol amine compound is 0%-99%.

9. The method for gentle full recycling of a degradable epoxy resin composite with adjustable curing speed according to claim 8, characterized in that: The Lewis acid catalyst is one or more of aluminum trichloride, ferric trichloride, titanium tetrachloride, boron trifluoride, boron trichloride, zinc chloride, trimethylaluminum, diethylzinc, triphenylboron, scandium trifluoromethanesulfonate, ytterbium trifluoromethanesulfonate, and aluminum chloride-imidazole salt; The amine compound is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, butanediamine, hexamethylenediamine, isophoronediamine, oleylamine, isopropylamine, tert-butylamine, benzylamine, cyclohexylamine, acrylamine and pyrrolidineamine; The alcohol compound is one or more of methanol, ethanol, isopropanol, butanol, cyclohexanol, glycerol, ethylene glycol, propylene glycol, butanediol, pentanediol, pentaerythritol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, polytetrahydrofuran diol, polypropylene glycol, castor oil-based diol, and polycarbonate diol; The alcoholamine compound is one or more of ethanolamine, diethanolamine, isopropanolamine, aminomethylpropanol, hydroxyethylethylenediamine, diglycolamine, 1-amino-2-propanol, 1-amino-2-butanol, phenylethanolamine, 2-amino-2-methyl-1-propanol, and 2-amino-1-butanol.

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