Method for regulating and controlling degradation rate of epoxy resin material

Abstract

The invention discloses a method for regulating and controlling the degradation rate of an epoxy resin material, and belongs to the technical field of epoxy resin materials.The method comprises the steps that raw materials of the epoxy resin material are regulated and controlled, so that the epoxy resin material comprises bisphenol epoxy resin, an anhydride curing agent and a curing accelerator; wherein the anhydride curing agent comprises hydrogenated phthalic anhydride and an alkylated derivative thereof; the curing accelerator comprises 1, 5, 7-triazabicyclo [4.4. 0] dec-5-ene (TBD), and the curing accelerator comprises 1, 5, 7-triazabicyclo [4.4. 0] dec-5-ene The epoxy resin material is degraded by adopting an alcohol degradation solution containing a TBD catalyst after being decommissioned. According to the degradation regulation and control method, the epoxy resin material has good mechanical properties and thermal stability in the service period, the performance requirements of electrical equipment for insulating materials are met, and efficient and controllable degradation can be achieved according to needs after decommissioning.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin materials, and in particular to a method for regulating the degradation rate of epoxy resin materials. Background Art

[0002] Epoxy resins, due to their excellent physical and chemical properties, are widely used as electrical insulation materials for high-voltage electrical equipment. Among common epoxy resin curing systems, anhydride curing agents, due to their high reactivity, low volatility, and excellent heat resistance, are the preferred curing agents for electrical insulation materials and high-performance composite materials. Typical anhydride curing agents include tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (Me-THPA), and methylhexahydrophthalic anhydride (Me-HHPA).

[0003] When designing traditional anhydride-cured epoxy resin systems, they often only focus on the mechanical properties and thermal stability required during their service phase, but lack a systematic design for their controllable degradation behavior after retirement. This makes it difficult for epoxy resin materials to achieve the high performance required for service while taking into account their degradability after retirement, resulting in waste of resources and environmental burden.

[0004] Existing research on the degradation of retired epoxy resin materials has largely focused on optimizing degradation solvents and catalysts, while neglecting the intrinsic regulatory effect of anhydride functional groups in the curing system on the cross-linked network. This results in poor universality of existing degradation processes, as well as widespread problems such as low degradation efficiency and high energy consumption. These shortcomings have severely restricted the widespread application of epoxy resin materials in the field of electrical equipment.

[0005] Therefore, there is an urgent need in this field to provide a degradation regulation method for epoxy resin materials, so that the epoxy resin materials have good mechanical properties and thermal stability during service, meet the performance requirements of electrical equipment for insulating materials, and can achieve efficient and controllable degradation on demand after retirement. Summary of the Invention

[0006] In response to the above-mentioned problems existing in the prior art, the present invention provides a method for regulating the degradation rate of an epoxy resin material, the method comprising: regulating the raw materials of the epoxy resin material so that it includes: a bisphenol epoxy resin, an acid anhydride curing agent and a curing accelerator; wherein the acid anhydride curing agent includes hydrogenated phthalic anhydride and its alkylated derivatives; and the curing accelerator includes 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).

[0007] In some embodiments of the present invention, the raw materials of the epoxy resin material include: 100 parts by mass of bisphenol epoxy resin; 75-90 parts by mass of anhydride curing agent; and 1-3 parts by mass of curing accelerator.

[0008] In some embodiments of the present invention, the anhydride curing agent is selected from one or more of the following anhydrides: tetrahydrophthalic anhydride THPA, hexahydrophthalic anhydride HHPA, methyltetrahydrophthalic anhydride Me-THPA and methylhexahydrophthalic anhydride Me-HHPA.

[0009] In some embodiments of the present invention, the epoxy resin material is degraded by alcoholysis after being retired.

[0010] In some embodiments of the present invention, the alcoholysis uses an alcohol degradation solvent and an organic base catalyst.

[0011] In some embodiments of the present invention, the alcohol degradation solvent includes an ethylene glycol solution, and the organic base catalyst includes 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0012] In some embodiments of the present invention, the ethylene glycol solution contains 5 to 15 wt % of 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0013] In some embodiments of the present invention, the bisphenol epoxy resin includes bisphenol A epoxy resin.

[0014] In some embodiments of the present invention, the alcoholysis temperature ranges from 157.45 to 197°C.

[0015] In some embodiments of the present invention, the crosslinking density of the epoxy resin material formed by curing is 12000~19000 mol / m 3 or 12000~16000mol / m 3 .

[0016] In some embodiments of the present invention, the epoxy resin material formed by curing has a glass transition temperature Tg of 110-160° C. and a storage modulus E′ of 26-40 MPa.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] The epoxy resin material degradation rate control method of the present invention breaks through the limitations of the existing technology of relying solely on a single optimization path dominated by degradation solvents or catalysts. Starting from the epoxy resin material design level, the present invention studies the coordinated control of the cross-linking network construction and degradation behavior by the anhydride curing agent and the curing accelerator TBD, so that the epoxy resin material has good mechanical properties and thermal stability during service, meets the performance requirements of electrical equipment for insulating materials, and can achieve efficient and controllable degradation on demand after retirement, providing an effective control path for epoxy resin materials in terms of balancing high performance and sustainable recycling design.

[0019] On the one hand, the regulation method of the present invention performs degradation regulation during the design stage of the epoxy resin material. Specifically, by selecting an anhydride curing agent with a specific functional group and adding a curing accelerator to the curing system, the crosslinking density of the epoxy resin material is regulated. While meeting the mechanical properties and thermal stability required by the epoxy resin material during the service stage, the controllable degradation behavior after retirement is taken into account, thereby regulating the degradation rate of the epoxy resin material after retirement.

[0020] On the other hand, the present invention organically combines the degradation control in the design stage of epoxy resin materials with the degradation control after retirement, selects an ethylene glycol degradation solution containing a degradation catalyst TBD to degrade retired epoxy resin materials, and further controls its degradation rate to a desired range. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are photos of the degradation systems of the epoxy resin material samples of Example 1 (THPA), Example 3 (HHPA), Example 5 (Me-THPA), and Example 7 (Me-HHPA) at the beginning of degradation (0 h), degradation 1 h, degradation 2 h, and degradation 4 h.

[0022] Figure 2 These are photographs of the appearance of the epoxy resin material samples of Example 1 (THPA), Example 3 (HHPA), Example 5 (Me-THPA), and Example 7 (Me-HHPA) at the beginning of degradation (0 h), 1 h, 2 h, 3 h, 3 h 20 min, and 5 h of degradation.

[0023] Figure 3 These are photos of the degradation systems of the epoxy resin material samples of Example 2 (THPA), Example 4 (HHPA), Example 6 (Me-THPA), and Example 8 (Me-HHPA) at the beginning of degradation (0 h), degradation 1 h, degradation 2 h, and degradation 4 h.

[0024] Figure 4 The results of Fourier transform infrared spectrometer (FTIR) analysis of the degradation products of the epoxy resin material sample of Example 3 after 2 hours of degradation are compared with those of the corresponding undegraded epoxy resin material.

[0025] Figure 5 The results of Fourier transform infrared spectrometer (FTIR) analysis of the degradation products of the epoxy resin material sample of Example 5 after degradation for 2 hours are compared with those of the corresponding undegraded epoxy resin material.

[0026] Figure 6 The results of Fourier transform infrared spectrometer (FTIR) analysis of the degradation products of the epoxy resin material sample of Example 7 after 2 hours of degradation are compared with those of the corresponding undegraded epoxy resin material. DETAILED DESCRIPTION

[0027] Various aspects of the present invention will be described in detail below in conjunction with specific implementation methods and exemplary embodiments. These specific descriptions and exemplary embodiments are only used to illustrate the present invention and do not constitute any limitation on the scope of protection of the present invention.

[0028] The present invention combines the control of material design and degradation conditions for the control of the degradation rate of epoxy resin materials.

[0029] The epoxy resin material of the present invention includes an anhydride-cured epoxy resin, which forms a crosslinked network through the reaction of an anhydride curing agent with epoxy groups. The anhydride-cured epoxy resin material of the present invention comprises a bisphenol epoxy resin as the epoxy resin matrix, such as bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, etc. In an exemplary embodiment of the present invention, bisphenol A epoxy resin DER 331 is selected.

[0030] Among the raw materials of the epoxy resin material of the present invention, an acid anhydride curing system is selected, wherein the acid anhydride curing agent includes phthalic anhydride and its hydrogenated or alkylated derivatives, such as tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (Me-THPA) and methylhexahydrophthalic anhydride (Me-HHPA).

[0031] Among the raw materials of the epoxy resin material of the present invention, 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) is selected as a curing accelerator to promote the reaction of anhydride with epoxy groups through a ring-opening reaction to form a cross-linked network.

[0032] Modifying agents, such as toughening agents, fillers, flame retardants, etc., may be added to the raw materials of the epoxy resin material of the present invention according to application requirements.

[0033] In the raw material composition of the anhydride-cured epoxy resin of the present invention, the mass of the epoxy resin is used as the basis (100 parts), and other components are expressed in parts per hundred resin (phr).

[0034] In the anhydride-cured bisphenol epoxy resin system of the present invention, the cross-linking density of the cross-linked network of the curing system is regulated by selecting the functional groups of the anhydride curing agent and adding 1 to 3 parts by mass of TBD as a curing accelerator, so that the cross-linked network formed by curing can not only meet the mechanical properties and thermal stability required for the service of the epoxy resin material, but also meet the controllable degradation requirements of the material after retirement.

[0035] The epoxy resin material regulated according to the exemplary embodiment of the present invention has a tensile strength of 72.64-81.4 MPa, a flexural strength of 119.25-133.46 MPa, and an impact strength of 15.85-22.10 KJ / m 2 between.

[0036] In the anhydride-cured bisphenol epoxy resin system of the present invention, the molar ratio of anhydride to epoxy group can be proportioned according to the reaction equivalent. In an exemplary embodiment of the present invention, the molar ratio of anhydride to epoxy group is 0.8-1.1:1 (equivalent to 75-90 parts by mass of anhydride).

[0037] The anhydride-cured epoxy resin material of the present invention can be prepared by referring to conventional curing processes of anhydride-cured epoxy resins known in the art, or can be prepared by using the exemplary embodiments of the present invention.

[0038] In the epoxy resin material degradation control method of the present invention, in order to combine with the degradation control measures in the material design stage, the degradation conditions of the epoxy resin material of the present invention after decommissioning can be further controlled, for example, by degradation via alcoholysis under catalytic conditions. Specifically, an alcohol is selected as the degradation solvent, and an organic base is selected as the degradation catalyst. In an exemplary embodiment of the present invention, ethylene glycol is used as the degradation solvent, and TBD is used as the degradation catalyst. The TBD content in the ethylene glycol solution ranges from 5 to 15 wt%, preferably from 8 to 12 wt%.

[0039] In the degradation control of retired epoxy resin materials, the alcoholysis reaction temperature should be higher than the glass transition temperature threshold Tg of the degradation material, but lower than the boiling point of the degradation solvent ethylene glycol, 197°C. For example, the degradation temperature range can be 157.45-197°C. In an exemplary embodiment of the present invention, the degradation temperature is set to 160°C.

[0040] The present invention will be further described in detail below with reference to exemplary embodiments of the present invention.

[0041] Example 1 In the degradation control method of this embodiment, in terms of the design of the epoxy resin material, tetrahydrophthalic anhydride (THPA) is selected as the anhydride curing agent, bisphenol A epoxy resin DER331 is selected as the epoxy resin matrix, and a curing accelerator TBD is added to the curing system at a ratio of 1 part by mass to the epoxy resin. The preparation steps of the THPA anhydride curing system epoxy resin material are as follows: Step 1: Preparation and blending of curing mixture Solid anhydride curing agent tetrahydrophthalic anhydride (THPA), epoxy resin DER331, and accelerator 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) were weighed at a mass ratio of DER331:THPA:TBD of 100:77.60:1 and placed in a three-necked flask. The flask was placed in an oil bath at 100°C and in-situ melt blending was carried out at a speed of 300 rad / min for 1 hour to ensure that the curing agent THPA was fully melted and evenly dispersed, and to achieve pre-dispersion interface optimization.

[0042] Step 2: Formation of epoxy resin cured sample The uniformly blended casting material obtained in step 1 is poured into a preheated mold, and then the mold is placed in a blast oven for curing. The pre-curing temperature is 80°C for 4 hours; the post-curing temperature is 140°C for 12 hours. After demolding, the epoxy resin test sample is obtained.

[0043] Step 3: Cutting, cleaning and drying of samples The cured epoxy resin samples were cut into standard test specimens, measuring 10 mm × 20 mm × 4 mm. After cutting, the specimens were placed in anhydrous ethanol and ultrasonically cleaned for 15 minutes to remove surface impurities. After cleaning, the specimens were transferred to a vacuum drying oven at 60°C and dried for 24 hours to constant weight for subsequent mechanical property and degradation control testing.

[0044] Step 4: Mechanical properties, thermal stability testing and crosslink density calculation Dynamic mechanical properties of the THPA-cured epoxy resin were tested using a dynamic mechanical analyzer (DMA). The test results showed that the storage modulus (E′) of the epoxy resin material was 27.06 MPa and the glass transition temperature (Tg) was 146.21°C.

[0045] The crosslinking density is calculated based on the equation derived from rubber elasticity theory:

[0046] in: v eis the cross-link density (mol / m³); Tg is the glass transition temperature (K); E′ is the storage modulus at Tg+40°C (Pa); R is the gas constant, which is 8.314.

[0047] The crosslinking density of the epoxy resin material of Example 1 was calculated according to the above formula to be 12935.39 mol / m³.

[0048] In addition, the mechanical properties of the sample of this embodiment were tested, and the bending strength was measured to be 119.25 MPa, the tensile strength was 72.64 MPa, and the impact strength was 15.85 KJ / m 2 .

[0049] Step 5: Degradation Condition Control of THPA Curing System Epoxy Resin Materials In order to further regulate the degradation behavior of epoxy resin materials, this embodiment uses an ethylene glycol solution containing 10wt% TBD as the degradation medium. The degradation temperature must meet the following two conditions: on the one hand, the degradation temperature must be higher than the glass transition temperature threshold of the sample (Tg = 146.21°C) to promote the penetration and diffusion of the degradation solution in the epoxy resin material; on the other hand, in order to prevent the volatilization of the degradation solvent, the degradation temperature must be controlled below the boiling point of ethylene glycol (197°C). Taking these two factors into consideration, the degradation temperature range is 146.21°C to 197°C. In this embodiment, the degradation temperature is 160°C. The degradation test is as follows: First, the initial mass m0 of the epoxy resin material sample is measured.

[0050] The weighed epoxy resin material sample was immersed in 10 mL of ethylene glycol solution containing 10 wt% TBD.

[0051] The degradation test uses a glass container sealed with aluminum foil to encapsulate the degradation reaction system and place it in a constant temperature oven at 160°C. The mass loss of the sample is measured at the preset time points and the degradation solution is observed and analyzed. Figure 1 The color changes of the degradation solution of the epoxy resin material sample of Example 1 at the beginning of degradation (0 h), degradation 1 h, degradation 2 h and degradation 4 h are shown. Figure 2 The graph shows the changes in sample size of the epoxy resin material sample of this example at the beginning of degradation (0h), 1h, 2h, 3h, 3h 20min, and 5h of degradation, from which we can see the evolution of sample size with degradation time.

[0052] In addition, this embodiment measures the mass loss of the samples taken at the preset time points and calculates the degradation rate. Specifically, the samples were ultrasonically cleaned with anhydrous ethanol and vacuum dried at 60°C to a constant weight. The mass of the epoxy samples at each time point was measured using a precision analytical balance and recorded. m i To degrade i After each degradation node measurement is completed, the sample is returned to the original degradation solution to continue the degradation reaction.

[0053] Degradation rate calculation and degradation control performance analysis: In order to evaluate the degradation behavior of epoxy resin material samples under different curing systems, the degradation rate of the epoxy resin material at the preset time point was calculated based on the mass measurement results at the preset time point. The degradation rate was calculated according to the following formula:

[0054] in: m0 is the initial mass of the sample before degradation (g); m i is the remaining mass of sample i at degradation time point (g); In this embodiment, according to experimental data, a THPA epoxy system containing 1 part by mass of TBD is completely degraded after 2 hours, and the corresponding degradation rate is 100%.

[0055] Example 2 The degradation control method of Example 2 differs from that of Example 1 only in that the mass fraction of TBD in the curing system is 3, and the raw material composition is based on a mass ratio of DER331:THPA:TBD of 100:77.60:3. The other conditions are the same as those of the degradation control method of Example 1.

[0056] The dynamic mechanical properties of the epoxy resin material of Example 2 were tested using a dynamic mechanical analyzer (DMA) as in Example 1. The storage modulus (E′) was measured to be 26.27 MPa and the glass transition temperature (Tg) was 115.14°C. The crosslink density of the THPA curing system of Example 2 was calculated to be 13564.03 mol / m 3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 125.42 MPa, the tensile strength was 75.36 MPa, and the impact strength was 17.60 KJ / m 2 .

[0057] In addition, the sample of Example 2 was degraded under the same degradation conditions as Example 1. The color changes of the degradation solution of the sample at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 3 shown.

[0058] The epoxy resin sample prepared in Example 2 degraded for 2 hours, and its mass decreased from 1.52 g to 0.45 g. The degradation rate was about 70%, which was 30% lower than that of the system with 1 part by mass of TBD in Example 1.

[0059] Example 3 The degradation control method of Example 3 differs from that of Example 1 only in that the anhydride curing agent in the curing system is replaced with hexahydrophthalic anhydride (HHPA), and the raw material composition is based on a mass ratio of DER331:HHPA:TBD of 100:78.62:1. The remaining conditions are the same as those of the degradation control method of Example 1.

[0060] As in Example 1, the dynamic mechanical properties of the epoxy resin material sample of Example 3 were tested using a dynamic mechanical analyzer (DMA). The storage modulus (E′) was measured to be 27.32 MPa and the glass transition temperature (Tg) was 148.01°C. The crosslink density of the HHPA curing system of Example 3 was calculated to be 13003.86 mol / m 3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 122.16 MPa, the tensile strength was 73.06 MPa, and the impact strength was 16.03 KJ / m 2 .

[0061] In addition, the sample of Example 3 was subjected to degradation test under the same degradation conditions. The color changes of the degradation solution at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 1 shown.

[0062] The appearance photos of the sample in this example at the beginning of degradation (0h), degradation 1h, 2h, 3h, 3h 20min and 5h are as follows: Figure 2 As shown, the evolution of the specimen size with degradation time can be seen.

[0063] The epoxy resin sample prepared in Example 3 degraded for 2 hours, and its mass decreased from 1.0 g to 0.11 g, with a degradation rate of about 89%.

[0064] Example 4 The degradation control method of Example 4 differs from that of Example 3 only in that the mass fraction of TBD in the curing system is 3, and the raw material composition is based on a mass ratio of DER331:HHPA:TBD of 100:78.62:3. The other conditions are the same as those of the degradation control method of Example 1.

[0065] The dynamic mechanical properties of the epoxy resin material of Example 4 were tested using a dynamic mechanical analyzer (DMA) as in Example 1. The storage modulus (E′) was measured to be 29.91 MPa and the glass transition temperature (Tg) was 154.66°C. The crosslink density of the HHPA curing system of Example 4 was calculated to be 14016.90 mol / m 3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 127.59 MPa, the tensile strength was 76.98 MPa, and the impact strength was 18.53 KJ / m 2 .

[0066] In addition, the sample of Example 4 was degraded under the same degradation conditions. The color changes of the degradation solution of the sample at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 3 shown.

[0067] The epoxy resin sample prepared in Example 4 degraded for 2 hours, and its mass decreased from 1.42 g to 0.86 g, with a degradation rate of about 39.16%. The degradation rate was 48.84% lower than that of the system with 1 part by mass of TBD in Example 3.

[0068] Example 5 The degradation control method of Example 5 differs from that of Example 1 in that the anhydride curing agent in the curing system is replaced with methyltetrahydrophthalic anhydride (Me-THPA). During the preparation and blending of the curing mixture, the liquid anhydride curing agent Me-THPA is prepared with the epoxy resin DER331 and TBD in a mass ratio of DER331: Me-THPA:TBD of 100:84.66:1. The raw material composition is placed in a three-necked flask, stirred at a rate of 300 rad / min, at a temperature of 80°C, with a vacuum degree of ≤100 Pa, and for 30 minutes to obtain a uniformly dispersed castable. The remaining conditions are the same as those for the degradation control in Example 1.

[0069] The dynamic mechanical properties of the epoxy resin material sample of Example 5 were tested using a dynamic mechanical analyzer (DMA) as in Example 1. The storage modulus (E′) was measured to be 39.59 MPa and the glass transition temperature (Tg) was 157.45°C. The crosslink density of the Me-THPA curing system of Example 5 was calculated to be 18431.06 mol / m 3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 130.97 MPa, the tensile strength was 79.41 MPa, and the impact strength was 21.29 KJ / m 2 .

[0070] In addition, the sample of Example 5 was subjected to degradation test under the same degradation conditions. The color changes of the degradation solution at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 1 shown.

[0071] The appearance photos of the sample in this example at the beginning of degradation (0h), degradation 1h, 2h, 3h, 3h 20min and 5h are as follows: Figure 2 As shown, the evolution of the specimen size with degradation time can be seen.

[0072] The epoxy resin sample prepared in Example 5 degraded for 2 hours, and its mass decreased from 1.0 g to 0.33 g, with a degradation rate of about 67%.

[0073] Example 6 The degradation control method of Example 6 differs from that of Example 5 only in that the mass fraction of TBD in the curing system is 3, and the raw material composition is prepared according to a mass ratio of DER331: Me-THPA: TBD of 100: 84.66:3. The other conditions are the same as those of the degradation control method of Example 5.

[0074] The dynamic mechanical properties of the epoxy resin material of Example 6 were tested using a dynamic mechanical analyzer (DMA) as in Example 1. The storage modulus (E′) was measured to be 36.21 MPa and the glass transition temperature (Tg) was 118.02°C. The crosslink density of the Me-THPA curing system of Example 6 was calculated to be 18556.74 mol / m 3 The mechanical properties of the sample of this embodiment were tested, and the bending strength was measured to be 133.46 MPa, the tensile strength was 81.40 MPa, and the impact strength was 22.10 KJ / m 2 .

[0075] In addition, the sample of Example 6 was degraded under the same degradation conditions. The color changes of the degradation solution of the sample at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 3 shown.

[0076] The epoxy resin sample prepared in Example 6 degraded for 2 hours, and its mass decreased from 1.71 g to 1.20 g. The degradation rate was about 30%, which was 37% lower than that of the system with 1 part by mass of TBD in Example 5.

[0077] Example 7 The degradation control method of Example 7 differs from that of Example 5 in that the anhydride curing agent in the curing system is replaced with methylhexahydrophthalic anhydride (Me-HHPA). During the preparation and blending of the curing mixture, the liquid anhydride curing agent Me-HHPA is mixed with the epoxy resin DER331 and TBD in a mass ratio of DER331:Me-HHPA:TBD of 100:85.78:1. The remaining conditions for the preparation of the epoxy resin material are the same as those in Example 5.

[0078] As in Example 1, the dynamic mechanical properties of the epoxy resin material sample of Example 7 were tested using a dynamic mechanical analyzer (DMA). The storage modulus (E′) was measured to be 27.84 MPa and the glass transition temperature (Tg) was 143.22°C. The crosslink density of the Me-HHPA curing system of Example 7 was calculated to be 13403.82 mol / m 3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 124.63 MPa, the tensile strength was 74.85 MPa, and the impact strength was 16.86 KJ / m 2 .

[0079] In addition, the sample of Example 7 was subjected to degradation test under the same degradation conditions. The color changes of the degradation solution at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 1 shown.

[0080] The appearance photos of the sample in this example at the beginning of degradation (0h), degradation 1h, 2h, 3h, 3h 20min and 5h are as follows: Figure 2 As shown, the evolution of the specimen size with degradation time can be seen.

[0081] The epoxy resin sample prepared in Example 7 degraded for 2 hours, and its mass decreased from 1.0 g to 0.12 g, with a degradation rate of about 88%.

[0082] Example 8 The degradation control method of Example 8 differs from that of Example 7 only in that the mass fraction of TBD in the curing system is 3, and the raw material composition is prepared according to a mass ratio of DER331: Me-HHPA: TBD of 100: 85.78:3. The other conditions are the same as those of the degradation control method of Example 7.

[0083] The dynamic mechanical properties of the epoxy resin material of Example 8 were tested using a dynamic mechanical analyzer (DMA) as in Example 1. The storage modulus (E′) was measured to be 32.40 MPa and the glass transition temperature (Tg) was 151.40°C. The crosslink density of the Me-HHPA curing system of Example 8 was calculated to be 15298.00 mol / m3 The mechanical properties of the sample in this embodiment were tested, and the bending strength was measured to be 129.68 MPa, the tensile strength was 78.52 MPa, and the impact strength was 19.71 KJ / m 2 .

[0084] In addition, the sample of Example 8 was degraded under the same degradation conditions. The color changes of the degradation solution of the sample at the beginning of degradation (0h), degradation 1h, degradation 2h and degradation 4h were as follows: Figure 3 shown.

[0085] The epoxy resin sample prepared in Example 8 degraded for 2 hours, and its mass decreased from 1.12 g to 0.73 g. The degradation rate was about 34.78%, which was 54.22% lower than that of the system with 1 part by mass of TBD in Example 7.

[0086] In addition, in order to further evaluate the degradation behavior, the degradation products extracted after 2 hours of degradation in Example 5 and the corresponding undegraded Me-THPA cured epoxy resin samples were analyzed using a Nicolet 67 Fourier transform infrared spectrometer (FTIR) produced by Thermo Nicolet. The FTIR analysis results are shown in Figure 2. Figure 5 The results showed that the recovered degradation products showed obvious hydroxyl vibration (3300~3500cm -1 ), indicating that alcohol decomposition releases hydroxyl groups; the ether group is located at 1243 cm -1 and 1182 cm -1 The -COC peak of the epoxy resin did not decrease, indicating that the main chain skeleton of the epoxy resin was not broken after degradation; the peak at 1735 cm -1 The C=O peak intensity of the ester bond has almost disappeared, indicating that the ester bond has been cleaved. This result shows that the alcoholysis reaction is complete and all esters have been cleaved and released.

[0087] The degradation products (degraded for 2 hours) and the corresponding undegraded products of the curing agent systems in Example 3 and Example 7 were analyzed by FTIR using the same method. The analysis results are as follows: Figure 4 and Figure 6 As shown, both show the same Figure 5 The same effect indicates that the alcoholysis reactions are complete.

[0088] For ease of comparison, the glass transition temperature Tg, storage modulus E', crosslinking density, flexural strength, tensile strength, impact strength and degradation rate data of the epoxy resin materials in Examples 1-8 are summarized in Table 1 below.

[0089] Table 1 Summary of test data of Examples 1-8

[0090]

[0091] As shown in Table 1, the degradation control methods of Examples 1-8 of the present invention, by adding the curing accelerator TBD to the anhydride curing agent system and using an ethylene glycol solution containing TBD as the degradation medium after decommissioning, effectively achieve both the required mechanical properties and thermal stability of the epoxy resin material in service and the controllable degradation requirements after decommissioning. Furthermore, the controllable degradation of the epoxy resin material can be further improved by selecting the anhydride curing agent system and controlling the content of the curing accelerator TBD.

[0092] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, the elements defined by the term "comprises" do not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the elements.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention and cannot be used to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field should understand that: without departing from the essence and scope of the present invention, the technical solutions described in the above embodiments can still be modified, or some of the technical features therein can be replaced by equivalents; and these modifications or equivalent replacements still fall within the scope covered by the present invention.

Claims

1. A method for regulating the degradation rate of epoxy resin material, characterized in that: The method includes: The raw materials of the epoxy resin material are regulated to include: bisphenol epoxy resin, anhydride curing agent and curing accelerator; wherein: The anhydride curing agent includes hydrogenated phthalic anhydride and its alkylated derivatives; The curing accelerator includes 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

2. The method according to claim 1, wherein The raw materials of the epoxy resin material include: 100 parts by mass of bisphenol epoxy resin; 75-90 parts by mass of anhydride curing agent; 1~3 parts by mass of curing accelerator.

3. The method according to claim 1 or 2, wherein The acid anhydride curing agent is selected from one or more of the following acid anhydrides: tetrahydrophthalic anhydride THPA, hexahydrophthalic anhydride HHPA, methyltetrahydrophthalic anhydride Me-THPA and methylhexahydrophthalic anhydride Me-HHPA.

4. The method of claim 3, further comprising: After the epoxy resin material is retired, it is degraded by alcoholysis.

5. The method according to claim 4, wherein the alcoholysis adopts an alcohol degradation solvent and an organic base catalyst.

6. The method according to claim 5, wherein the alcohol degradation solvent comprises an ethylene glycol solution, and the organic base catalyst comprises 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

7. The method according to claim 6, wherein: The ethylene glycol solution contains 5-15 wt % of 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

8. The method of claim 1, wherein: The bisphenol epoxy resin includes bisphenol A epoxy resin.

9. The method of claim 4, wherein: The alcoholysis temperature range is 157.45~197°C.

10. The method of claim 1, wherein: The crosslinking density of the cured epoxy resin material is 12000~19000 mol / m 3 .

11. The method according to claim 10, wherein: The crosslinking density of the cured epoxy resin material is 12000~16000 mol / m 3 .

12. The method of claim 3, wherein: The glass transition temperature Tg of the epoxy resin material formed by curing is 110~160℃ and the storage modulus E' is 26~40 MPa.

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