A degradation reagent, degradation method and application of degradation products of anhydride-cured epoxy resin composite material

Abstract

The present invention discloses a degradation reagent, a degradation method and an application of the degradation product of an anhydride-cured epoxy resin composite material, and relates to the field of solid waste material recovery. The degradation reagent includes a catalyst and a solvent, and the solvent is a strong alkaline aqueous solution; the structure of the catalyst is p-hydroxybiphenyl with a hydrogen group or a cyano group connected to the benzene ring; the degradation method is to heat the anhydride-cured epoxy resin composite material and the degradation reagent to react, neutralize and concentrate under reduced pressure, precipitate and dry to obtain a degradation product. The present application deprotonates the phenolic hydroxyl group of the catalyst under alkaline conditions to form phenol oxide anions, which react with the anhydride groups in the anhydride-cured epoxy resin composite material to break the anhydride groups, thereby achieving high-efficiency degradation. The degradation method is simple to operate and environmentally friendly, and the degradation product has good comprehensive performance after curing and regeneration with the anhydride curing agent, thereby improving its recycling value.

Description

Technical Field

[0001] The present invention relates to the field of solid waste material recovery, and in particular to a degradation reagent and a degradation method of an anhydride-cured epoxy resin composite material, and applications of degradation products. Background Art

[0002] With the rapid development of new energy, smart grids, and power electronics, equipment is moving toward miniaturization, high frequency, and high power. This has led to a sharp increase in the heat generated per unit volume of electronic and power equipment, placing higher demands on the high-temperature resistance of packaging materials for these devices. Epoxy resin composites, due to their excellent insulation, corrosion resistance, high-temperature resistance, and sealing properties, are widely used in the insulation and packaging of components such as transformers, insulating rods, and substations.

[0003] However, due to the excellent thermal stability and solvent resistance of epoxy resin composites, it is difficult to degrade epoxy resin composites in discarded electronic and electrical equipment. The degradation rate is low and the degradation time is long. Even if the epoxy resin composites are degraded and recycled, the performance of the recycled materials is difficult to meet the requirements for reuse in electronic and electrical equipment. Therefore, the degradation, recycling, and regeneration of epoxy resin composites have become urgent issues to be addressed in the power industry. Summary of the Invention

[0004] The present invention provides a degradation reagent, a degradation method and application of degradation products of an anhydride-cured epoxy resin composite material, so as to achieve degradation of the anhydride-cured epoxy resin composite material under relatively low temperature conditions, thereby improving degradation efficiency and the recycling value of the degradation products.

[0005] In order to solve the above technical problems, one of the purposes of the present invention is to provide a degradation agent for anhydride-cured epoxy resin composite materials, comprising the following components by weight: 20-40 parts of a catalyst; 40-80 parts of a solvent, wherein the solvent is a strong alkaline aqueous solution;

[0006] The general structural formula of the catalyst is: ;

[0007] wherein R1, R2, R3, R4, and R5 are each independently a hydrogen group or a cyano group, and R1, R2, R3, R4, and R5 are not hydrogen groups at the same time.

[0008] As a preferred embodiment, at least one of R1, R2, R3, R4, and R5 is a hydrogen group.

[0009] As a preferred embodiment, the strong base in the strong base aqueous solution is at least one of sodium hydroxide, potassium hydroxide, sodium tert-butoxide, and potassium tert-butoxide.

[0010] As a preferred solution, the solvent is a strong alkali aqueous solution with a mass fraction of 4%-8%.

[0011] As a preferred embodiment, the catalyst is 、 、 、 and At least one of .

[0012] In order to solve the above technical problems, the second object of the present invention is to provide a degradation method of an anhydride-cured epoxy resin composite material, using the degradation reagent of the anhydride-cured epoxy resin composite material, comprising the following steps:

[0013] (1) adding an anhydride-cured epoxy resin composite material and a degradation agent of the anhydride-cured epoxy resin composite material into a reaction device, heating the reaction for more than 4 hours, and naturally cooling the reaction to room temperature after the reaction is completed;

[0014] (2) Acid is added to neutralize the excess strong base, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain the degradation product of the anhydride-cured epoxy resin composite material.

[0015] The present application uses a degradation reagent to degrade anhydride-cured epoxy resin composite materials. Under alkaline conditions, the phenolic hydroxyl groups of the catalyst are deprotonated to form phenolic oxide anions, which can react with the anhydride groups in the anhydride-cured epoxy resin, causing the anhydride groups in the composite material to break. Heating is used to promote the reaction rate and achieve high-efficiency degradation. The degradation reagent of the present application can be used to degrade and recycle anhydride-cured epoxy resins in waste transformers, insulating rods, insulating components used in substations, or electronic components. The degradation method is simple to operate, environmentally friendly, and the degradation temperature is not high, which reduces energy consumption and enables the recycling and reuse of anhydride-cured epoxy resins.

[0016] As a preferred embodiment, in step (1), the mass ratio of the anhydride-cured epoxy resin composite material to the degradation agent of the anhydride-cured epoxy resin composite material is 1:(6-12).

[0017] As a preferred embodiment, in step (1), the heating reaction temperature is 60-80°C.

[0018] As a preferred embodiment, in step (1), the heating reaction time is 4-12 h.

[0019] As a preferred embodiment, in step (2), the acid is at least one of acetic acid, nitric acid, sulfuric acid, and hydrochloric acid.

[0020] In order to solve the above technical problems, the third object of the present invention is to provide an application of an anhydride-cured epoxy resin composite material degradation product in the preparation of an anhydride-cured epoxy resin composite material.

[0021] In order to solve the above technical problems, the fourth object of the present invention is to provide an anhydride-cured epoxy resin composite material, comprising an anhydride-cured epoxy resin composite material degradation product and an anhydride curing agent in a mass ratio of (0.8-1.2): (0.8-1.2).

[0022] As a preferred embodiment, the acid anhydride curing agent is at least one of 4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride, and hexahydrophthalic anhydride.

[0023] In this application, the recycled degradation products of the anhydride-cured epoxy resin composite material are regenerated by a curing reaction with an anhydride curing agent. The regenerated anhydride-cured epoxy resin composite material has a smaller reduction in bending strength, and the hardness can meet the application requirements. At the same time, the tensile strength of the material is improved, and the toughness of the material is better, thereby increasing its recycling and reuse value.

[0024] In order to solve the above technical problems, the fifth object of the present invention is to provide a method for preparing an anhydride-cured epoxy resin composite material, comprising the following steps: adding the degradation product of the anhydride-cured epoxy resin composite material and an anhydride curing agent into a reaction device, heating to carry out a curing reaction, the heating temperature being 100-130°C, and the curing reaction time being 15-30 minutes, to obtain the anhydride-cured epoxy resin composite material.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Under alkaline conditions, the degradation reagent of the present application deprotonates the phenolic hydroxyl groups of the catalyst to form phenolic oxide anions, which can react with the anhydride groups in the anhydride-cured epoxy resin composite material to break the anhydride groups in the composite material, thereby achieving high-efficiency degradation. The degradation method is simple to operate, environmentally friendly, and has a low degradation temperature, which reduces energy consumption and enables the recycling and reuse of the anhydride-cured epoxy resin.

[0027] 2. In this application, the recycled degradation products of the anhydride-cured epoxy resin composite material are regenerated by a curing reaction with an anhydride curing agent. The bending strength of the regenerated anhydride-cured epoxy resin composite material is reduced slightly, and the hardness can meet the application requirements. At the same time, the tensile strength of the material is improved, and the toughness of the material is better, thereby increasing its recycling and reuse value. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only 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 any creative efforts are within the scope of protection of the present invention.

[0029] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0030] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0031] In these examples, parts and percentages are by mass unless otherwise indicated.

[0032] In the description of the present invention, it should be understood that the terms "up", "down", "left", "right", "top", "bottom", etc., indicating directions or positional relationships, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0033] To further illustrate the present invention, the present invention is described in detail below with reference to the following examples, but they should not be construed as limiting the scope of the present invention. Unless otherwise specified, the sources of the raw materials used in the following examples and comparative examples of the present application are commercially available, and the same raw materials were used in parallel experiments.

[0034] Example 1

[0035] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0036] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0037] (2) 10 kg of anhydride-cured epoxy resin composite material, 20 kg of catalyst and 80 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 4% and the structural formula of the catalyst was (CAS No.: 2492-28-6), heated to 70 ° C, heated to react, during which the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 6 h, with a degradation rate of 100% within 6 h. After naturally cooling to room temperature;

[0038] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0039] Example 2

[0040] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0041] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0042] (2) 10 kg of anhydride-cured epoxy resin composite material, 40 kg of catalyst and 40 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 8% and the structural formula of the catalyst was (CAS No.: 2492-28-6), heated to 80 ° C, heated to react, during which the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 6 h, with a degradation rate of 100% within 6 h. After naturally cooling to room temperature;

[0043] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0044] Example 3

[0045] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0046] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0047] (2) 10 kg of anhydride-cured epoxy resin composite material, 30 kg of catalyst and 60 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 6% and the structural formula of the catalyst was (CAS No.: 2492-28-6), heated to 60 ° C, heated to react, during which the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 6 h, with a degradation rate of 100% within 6 h. After naturally cooling to room temperature;

[0048] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0049] Example 4

[0050] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0051] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0052] (2) 10 kg of anhydride-cured epoxy resin composite material, 30 kg of catalyst and 60 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 6% and the structural formula of the catalyst was , the temperature was raised to 60 ℃, and the reaction was heated. During the reaction, the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 6 h, and the degradation rate within 6 h was 100%. After cooling naturally to room temperature;

[0053] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0054] Example 5

[0055] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0056] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0057] (2) 10 kg of anhydride-cured epoxy resin composite material, 30 kg of catalyst and 60 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 6% and the structural formula of the catalyst was , the temperature was raised to 60 ℃, and the reaction was heated. During the reaction, the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material no longer continued to degrade after 5 h, and the degradation rates within 5 h and 6 h were both 89%. After cooling naturally to room temperature;

[0058] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0059] Example 6

[0060] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0061] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0062] (2) 10 kg of anhydride-cured epoxy resin composite material, 30 kg of catalyst and 60 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 6% and the structural formula of the catalyst was (CAS No.: 154848-44-9), heated to 60 ° C, heated to react, during which the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 5 h, with a degradation rate of 100% within 5 h. After naturally cooling to room temperature;

[0063] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0064] Example 7

[0065] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0066] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0067] (2) 10 kg of anhydride-cured epoxy resin composite material, 30 kg of catalyst and 60 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 6% and the structural formula of the catalyst was (CAS No.: 19812-93-2), heated to 60 ° C, heated to react, during which the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, and 6 h. It was found that the anhydride-cured epoxy resin composite material was completely degraded at 4 h, with a degradation rate of 100% within 4 h. After naturally cooling to room temperature;

[0068] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0069] Comparative Example 1

[0070] A method for degrading anhydride-cured epoxy resin composite material comprises the following steps:

[0071] (1) Tear up the waste transformer and remove the copper metal from it, and collect the anhydride-cured epoxy resin composite material;

[0072] (2) 10 kg of anhydride-cured epoxy resin composite material and 90 kg of sodium hydroxide aqueous solution were added into the reactor, wherein the solute mass fraction concentration of the sodium hydroxide aqueous solution was 4 wt %. The temperature was raised to 60 °C for heating reaction. During the reaction, the degradation of the anhydride-cured epoxy resin composite material was observed and recorded at 0 h, 1 h, 2 h, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, and 12 h. It was found that the anhydride-cured epoxy resin composite material could not be completely degraded after 12 h, and the degradation rate within 12 h was 46%. After natural cooling to room temperature;

[0073] (3) Acetic acid is added to neutralize the excess sodium hydroxide, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain an anhydride-cured epoxy resin composite degradation product.

[0074] Application Example 1

[0075] A method for preparing an anhydride-cured epoxy resin composite material comprises the following steps:

[0076] 80 kg of the anhydride-cured epoxy resin composite degradation product of Example 1 and 120 kg of hexahydrophthalic anhydride were added to a reactor, the temperature was raised to 100° C., and heat-cured for 30 minutes to obtain an anhydride-cured epoxy resin composite.

[0077] Application Example 2

[0078] A method for preparing an anhydride-cured epoxy resin composite material comprises the following steps:

[0079] 120 kg of the anhydride-cured epoxy resin composite degradation product of Example 2 and 80 kg of hexahydrophthalic anhydride were added to a reactor, the temperature was raised to 130° C., and heat-cured for 15 minutes to obtain an anhydride-cured epoxy resin composite.

[0080] Application Examples 3-7

[0081] A method for preparing an anhydride-cured epoxy resin composite material comprises the following steps:

[0082] 100 kg of the anhydride-cured epoxy resin composite degradation product of Example 3-7 and 100 kg of hexahydrophthalic anhydride were added to a reactor, the temperature was raised to 115° C., and heat-cured for 20 minutes to obtain an anhydride-cured epoxy resin composite.

[0083] Comparative Application Example 1

[0084] A method for preparing an anhydride-cured epoxy resin composite material comprises the following steps:

[0085] The waste transformer is torn into pieces and the metallic copper is taken out, and the anhydride-cured epoxy resin composite material is collected.

[0086] Performance testing

[0087] 1. In step (2) of the embodiment and the comparative example, the degradation rate of the anhydride-cured epoxy resin composite material was observed and calculated. The degradation rate was calculated as follows: the anhydride-cured epoxy resin composite material before the reaction in step (1) was weighed to obtain V0, the solution after the heating reaction in step (2) until the anhydride-cured epoxy resin composite material no longer degraded was filtered and separated, and the collected solid was weighed to obtain V1. The degradation rate (%) = (V0-V1) / V0×100%.

[0088] 2. The flexural strength and flexural modulus of the anhydride-cured epoxy resin composite materials prepared according to the corresponding use case and comparative application example of ISO178-2019 were tested. The test results are shown in Table 1 below.

[0089] 3. According to the method of standard GB / T 1843-2008, the impact strength of the anhydride-cured epoxy resin composites prepared in the corresponding application example and the comparative application example was tested using a Sansi ZBC-50 single-arm pendulum impact tester. The test results are shown in Table 1 below.

[0090] 4. Using a TA-Q200 differential scanning calorimeter produced by TA Instruments, USA, the glass transition temperature of the anhydride-cured epoxy resin composite materials prepared in the corresponding application example and the comparative application example was tested.

[0091] 5. According to the method of standard ISO527-2019, the anhydride-cured epoxy resin composite materials prepared in the application example and the comparative application example were cast into a dumbbell-shaped mold. After curing, demolding and surface polishing, a 4 mm thick standard specimen was obtained. The tensile properties were tested at a tensile rate of 5 mm / min. The results of tensile strength, tensile modulus and elongation at break are shown in Table 1 below.

[0092] Table 1 - Performance test results of anhydride-cured epoxy resin composite materials of the present application example and the comparative application example.

[0093]

[0094] As can be seen from Table 1, after the degradation products of the anhydride-cured epoxy resin composite materials of Examples 1-7 are regenerated by curing reaction with hexahydrophthalic anhydride, the flexural modulus, flexural strength, and impact strength of the regenerated materials are lower than those of the original anhydride-cured epoxy resin composite materials, but the glass transition temperature, tensile strength, tensile modulus, and elongation at break are all improved to a certain extent. The comprehensive performance is not much different from that of the anhydride-cured epoxy resin composite material that has not been degraded and recycled. This shows that the anhydride-cured epoxy resin degradation products obtained by the degradation method of the present application have high recycling value, and the degradation method is simple to operate and environmentally friendly.

[0095] The specific embodiments described above further illustrate the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A degradation agent for anhydride-cured epoxy resin composite material, characterized in that: The method comprises the following components in parts by weight: 20-40 parts of a catalyst; 40-80 parts of a solvent, wherein the solvent is a strong alkaline aqueous solution; The general structural formula of the catalyst is: ; wherein R1, R2, R3, R4, and R5 are each independently a hydrogen group or a cyano group, and R1, R2, R3, R4, and R5 are not hydrogen groups at the same time.

2. The degradation reagent for anhydride-cured epoxy resin composite material according to claim 1, wherein At least one of R1, R2, R3, R4, and R5 is a hydrogen group.

3. The degradation reagent for anhydride-cured epoxy resin composite material according to claim 1, wherein The solvent is a strong alkali aqueous solution with a mass fraction of 4%-8%.

4. The degradation reagent for anhydride-cured epoxy resin composite material according to claim 1, wherein The catalyst is 、 、 、 and At least one of; And / or, the strong base in the strong base aqueous solution is at least one of sodium hydroxide, potassium hydroxide, sodium tert-butoxide, and potassium tert-butoxide.

5. A method for degrading anhydride-cured epoxy resin composite material, characterized in that: The following steps are involved: (1) adding an anhydride-cured epoxy resin composite material and a degradation agent for the anhydride-cured epoxy resin composite material according to any one of claims 1 to 4 into a reaction device, heating the reaction for more than 4 hours, and naturally cooling the reaction to room temperature after the reaction is completed; (2) Acid is added to neutralize the excess strong base, the mixed solution is concentrated under reduced pressure, the concentrated solution is added dropwise to n-hexane for precipitation, and the precipitate is dried to obtain the degradation product of the anhydride-cured epoxy resin composite material.

6. The method for degrading anhydride-cured epoxy resin composite material according to claim 5, wherein: In step (1), the mass ratio of the anhydride-cured epoxy resin composite material to the degradation agent of the anhydride-cured epoxy resin composite material is 1:(6-12); and / or, in step (1), the heating reaction temperature is 60-80°C; and / or, in step (1), the heating reaction time is 4-12 h; And / or, in step (2), the acid is at least one of acetic acid, nitric acid, sulfuric acid, and hydrochloric acid.

7. Use of an anhydride-cured epoxy resin composite material degradation product in the preparation of an anhydride-cured epoxy resin composite material, characterized in that: The anhydride-cured epoxy resin composite material degradation product is prepared by the degradation method of the anhydride-cured epoxy resin composite material according to claim 5 or 6.

8. An anhydride-cured epoxy resin composite material, characterized in that: The invention comprises an anhydride-cured epoxy resin composite material degradation product and an anhydride curing agent in a mass ratio of (0.8-1.2): (0.8-1.2). The anhydride-cured epoxy resin composite material degradation product is prepared by the anhydride-cured epoxy resin composite material degradation method according to claim 5 or 6.

9. The anhydride-cured epoxy resin composite material according to claim 8, wherein: The acid anhydride curing agent is at least one of 4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, 4-methylhexahydrophthalic anhydride and hexahydrophthalic anhydride.

10. A method for preparing anhydride-cured epoxy resin composite material according to claim 8 or 9, characterized in that: The following steps are involved: The anhydride-cured epoxy resin composite material degradation product and an anhydride curing agent are added to a reaction device, and heated to perform a curing reaction at a heating temperature of 100-130° C. and a curing reaction time of 15-30 minutes to obtain the anhydride-cured epoxy resin composite material.

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