A high temperature resistant epoxy system, its preparation method and use

Abstract

The application provides a high-temperature-resistant epoxy system, a preparation method and application thereof, and belongs to the field of advanced materials. The high-temperature-resistant epoxy system comprises the following raw materials in parts by weight: bisphenol F epoxy resin 5-35 parts, trifunctional epoxy resin 5-25 parts, tetrafunctional epoxy resin 5-25 parts, curing agent 40-80 parts, and accelerator 0.2-10 parts. The epoxy system of the application adopts epoxy resins with different functionalities, adjusts the crosslinking density of the epoxy system through formula design, realizes the purpose of simultaneously improving the glass transition temperature (T g ) and thermal stability of the epoxy system, and the prepared epoxy system has excellent flowability, processability and long-term temperature resistance, so that the epoxy system has a wide application prospect in the field of high-temperature-resistant sealing materials.

Description

Technical Field

[0001] This invention relates to the field of advanced materials, and in particular to a high-temperature resistant epoxy system, its preparation method, and its applications. Background Technology

[0002] Carbon-graphite materials are layered or network structures composed of carbon elements. They possess characteristics such as high temperature resistance, good chemical stability, and excellent self-lubrication, and are commonly used as sealing materials in household appliances, automotive, and aerospace industries. However, their inherent structural characteristic of porosity imposes certain limitations on practical applications: for example, it may lead to media leakage in high-pressure sealing, affecting equipment operating efficiency; and high porosity, as an internal defect, results in reduced material mechanical strength and insufficient wear and impact resistance.

[0003] Epoxy resins are widely used due to their excellent chemical resistance, superior mechanical properties, and low cost. When used to modify carbon graphite materials, low-viscosity epoxy resin liquids can penetrate the micropores and cracks of carbon graphite, forming a network structure within the material after curing. This network structure can act as a filler to fill pores and improve the overall strength of the material. Given the application scenarios, epoxy resin-modified carbon graphite materials need to withstand high temperatures over long periods. However, bisphenol F epoxy resins, with their excellent flowability, exhibit high thermal stability and a low glass transition temperature (T0). g It is difficult to meet the standards, so it is necessary to improve its thermal properties to meet the long-term temperature resistance requirements in practical applications.

[0004] By using two high-temperature resistant epoxy resins with different functionalities and good flowability, and adjusting the proportions of epoxy resins with different functionalities, it is beneficial to control the crosslinking density of the epoxy system, thereby achieving T... g The improvement is significant. For example, Chinese patent application CN119842350B uses trifunctional epoxy resin, tetrafunctional epoxy resin, and silicone-modified epoxy resin as component A of a high-temperature resistant epoxy resin adhesive, supplemented by a curing agent as component B, to prepare a high-temperature resistant electronic component bonding material; however, the silicone-modified epoxy resin and core-shell toughening agent in this patent are expensive, limiting its economic viability, and its glass transition temperature only reaches a maximum of 182℃. Summary of the Invention

[0005] To address the aforementioned problems in the existing technology, the present invention aims to provide a high-temperature resistant epoxy system, its preparation method, and its applications, which can simultaneously improve the TT of the epoxy system. g And thermal stability.

[0006] This invention provides a high-temperature resistant epoxy system comprising the following raw materials by weight: 5-35 parts of bisphenol F epoxy resin, 5-25 parts of trifunctional epoxy resin, 5-25 parts of tetrafunctional epoxy resin, 40-80 parts of curing agent, and 0.2-10 parts of accelerator.

[0007] Preferably, the high-temperature resistant epoxy system comprises the following raw materials by weight: 10-30 parts of bisphenol F epoxy resin, 10-20 parts of trifunctional epoxy resin, 10-20 parts of tetrafunctional epoxy resin, 50-70 parts of curing agent, and 0.5-2 parts of accelerator.

[0008] Preferably, the high-temperature resistant epoxy system comprises the following raw materials by weight: 20 parts of bisphenol F epoxy resin, 20 parts of trifunctional epoxy resin, 20 parts of tetrafunctional epoxy resin, 60 parts of curing agent, and 1 part of accelerator.

[0009] Furthermore, the high-temperature resistant epoxy system also includes the following raw materials by weight: 10-15 parts of naphthol-type epoxy resin.

[0010] Preferably, the high-temperature resistant epoxy system comprises the following raw materials by weight: 10 parts of bisphenol F epoxy resin, 20 parts of trifunctional epoxy resin, 10 parts of tetrafunctional epoxy resin, 10 parts of naphthol-type epoxy resin, 60 parts of curing agent, and 1 part of accelerator.

[0011] Furthermore, the trifunctional epoxy resin is selected from at least one of 4,5-epoxyhexane-1,2-dicarboxylic acid diglycidyl ester, N,N-diglycidyl-p-glycidyloxyaniline, and N,N-diglycidyl-4-glycidyloxyaniline; the tetrafunctional epoxy resin is selected from at least one of 4,4'-diaminodiphenylmethane tetraglycidylamine, 4,4'-diaminodiphenylsulfone tetraglycidylamine, m-phenylenediamine tetraglycidylamine, and pyromellitic tetraglycidyl ester; the curing agent is a cyclic anhydride compound; and the accelerator is an imidazole compound.

[0012] Furthermore, the cyclic anhydride compounds are selected from at least one of methylnadic anhydride, nadic anhydride, and methylbicyclo-2,2,1-heptane-2,3-dicarboxylic anhydride; the imidazole compounds are selected from at least one of 2-ethyl-4-methylimidazolium, 2-isopropyl-4-methylimidazolium, 2-butyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, and 2-phenyl-4-methylimidazolium.

[0013] This invention also provides a method for preparing a high-temperature resistant epoxy system, characterized by comprising the following steps: (1) Weigh the raw materials according to their weight components, and then melt and blend them together to obtain a molten liquid; (2) After stirring the molten liquid evenly, remove the air bubbles under vacuum, then pour it into a preheated mold, and heat it up to solidify according to the set program to obtain the solidified product.

[0014] Furthermore, the temperature for melt blending is 70~90℃; the temperature for vacuum degassing is 70~90℃; and the temperature curing program is set sequentially as 90~110℃ / 1~3h, 120~160℃ / 1~3h, and 170~200℃ / 2~5h.

[0015] This invention also provides the use of high-temperature resistant epoxy systems in sealing materials.

[0016] This invention utilizes epoxy resins with different functionalities to adjust the crosslinking density of the epoxy system through formulation design, and also introduces a high-temperature resistant naphthalene ring structure into the network, thereby simultaneously increasing the glass transition temperature (Tg) of the epoxy system. g The prepared epoxy system exhibits excellent flowability and processability, as well as long-term temperature resistance, due to its good thermal stability, making it more suitable for use in sealing materials.

[0017] Compared to epoxy resins without different functionalities, the bisphenol F epoxy / TDE-85 / AG-80 and bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy systems of the present invention exhibit significantly improved thermal stability. Compared to the bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy system, the bisphenol F epoxy / TDE-85 / AG-80 epoxy system exhibits significantly improved thermal stability. Among them, the bisphenol F epoxy / TDE-85 / AG-80 epoxy system obtained in Example 3 has the best thermal stability and an extremely low mass loss rate (0.04 wt% at 250°C for 2 hours).

[0018] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0019] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Detailed Implementation

[0020] In the following examples and experimental cases, reagents and raw materials not specifically described are all commercially available products.

[0021] The samples of the embodiments and comparative examples of the present invention were prepared by the following method, and the specific component ratios are shown in Table 1: (1) Weigh out bisphenol F epoxy resin, trifunctional epoxy resin, tetrafunctional epoxy resin, naphthol type epoxy resin, cyclic acid anhydride compound and imidazole compound according to the weight ratio shown in Table 1, and then place them in a beaker and melt-blend them in an oven at 80°C to obtain a melt. (2) After stirring the melt evenly, remove the air bubbles in a vacuum oven at 80°C, and then quickly and evenly pour it into a preheated mold. Heat and cure according to the set program to obtain the cured product. The heating and curing program is set to 100°C / 2h, 140°C / 2h, and 180°C / 3h respectively.

[0022] The components used were sourced as follows: bisphenol F epoxy resin NPEF-170 with an epoxy equivalent of 160-180 g / eq, a product of Nan Ya Plastics Industry Co., Ltd.; trifunctional epoxy resin TDE-85 with an epoxy equivalent of 105-125 g / eq, purchased from Chuzhou Huisheng Electronic Materials Co., Ltd.; tetrafunctional epoxy resin AG-80 with an epoxy equivalent of 125 g / eq, purchased from Jining Benok Biotechnology Co., Ltd.; naphthol-type epoxy resin ZLN-140S with an epoxy equivalent of 137-145 g / eq, purchased from Zhilun New Materials Technology (Xi'an) Co., Ltd.; cyclic anhydride compounds methylnadic anhydride and imidazole compounds 2-ethyl-4-methylimidazolium (2E4MZ), both purchased from Adamas.

[0023] Table 1. Specific formulations of the examples and comparative examples. The epoxy system samples prepared in the examples and comparative examples were characterized by the following test methods: (1) Dynamic thermomechanical analysis: DMA measurements were performed using a TA Q800 DMA instrument (TA, USA) in three-point bend mode; the heating rate was 5℃ / min, and the frequency was 1Hz; the sample size was a rectangular specimen of 25mm×4mm×2mm; the measurement temperature range was 30~250℃; T was determined based on the peak temperature of the tanδ curve. g ; (2) Thermal stability test: Thermal stability test was conducted using a TG 209 thermogravimetric analyzer (NETZSCH, Germany); the sample weight was kept within 5~10 mg; the first batch of samples was weighed, the test atmosphere was air, the heating rate was 10℃ / min, the measurement temperature range was 30-800℃, and the test temperature was T d5% / ℃ and T d30% / ℃; Weigh the second batch of samples, raise the temperature to 250℃ at the fastest heating rate, and then keep it at 250℃ for 2 hours. The test atmosphere is air, and the mass loss rate after 2 hours is / .

[0024] The dynamic mechanical properties of the epoxy system samples prepared in the examples and comparative examples are shown in Table 2. The storage modulus (40℃) and T0 of the samples were also tested using DMA. g This study aimed to reveal the relationship between the crosslinking structure and macroscopic properties of materials. Compared to the storage modulus of the unmodified epoxy system, the storage modulus of Comparative Example 1 was 2515 MPa. The storage modulus of the bisphenol F epoxy / TDE-85 / AG-80 epoxy system decreased to a minimum of 1615 MPa with changes in the content of each component, while the storage modulus of the bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy system decreased to a minimum of 1614 MPa with changes in the content of each component, showing an overall downward trend. Notably, the storage modulus of each formulation system decreased significantly after the addition of TDE-85, AG-80, and naphthol-type epoxy resins. g The energy storage modulus was significantly improved, reaching a maximum of 213°C, representing an increase of 54%. Among Examples 1-6, the bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy system obtained in Example 5 had the lowest storage modulus. g Highest.

[0025] Dynamic mechanical property experiments showed that, compared with the unmodified epoxy system in Comparative Example 1, modification of bisphenol F epoxy resin with TDE-85 / AG-80 or TDE-85 / AG-80 / naphthol type epoxy resins not only significantly improved its flowability, but also significantly suppressed chain slippage and relaxation behavior under high temperature conditions, significantly improving the TT of the epoxy system. g The temperature can reach as high as 213℃.

[0026] Table 2. Dynamic mechanical property test results of epoxy system samples prepared in the examples and comparative examples. The thermal stability test results of the epoxy system samples prepared in the examples and comparative examples are shown in Table 3. To further investigate the effects of epoxy resins with different functionalities and naphthol-type epoxy resins on the thermal stability of the bisphenol F epoxy system, TGA data for different epoxy systems were tested, and TGA was used to analyze the thermal stability of the bisphenol F epoxy system. d5% T d30% The thermal stability of the system was assessed by the 2-hour mass loss rate. The results showed that the epoxy system modified with TDE-85 / AG-80 or TDE-85 / AG-80 / naphthol-type epoxy resin exhibited good thermal stability at 2 hours. d5% Both showed better thermal stability than the unmodified system. Experimental results showed that the prepared bisphenol F epoxy / TDE-85 / AG-80 and bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy systems both have good thermal stability.

[0027] The mass loss rate was measured after maintaining a constant temperature of 250℃ for 2 hours. It was found that the mass loss rate of Examples 1-6 was significantly lower than that of Comparative Examples 1-2. Both the bisphenol F epoxy / TDE-85 / AG-80 and bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy systems have good thermal stability.

[0028] Among them, the 2-hour mass loss rate of Examples 1-3 is lower than that of Examples 4-6. In particular, the 2-hour mass loss rate of Example 3 is the lowest, reaching 0.04wt%, which is extremely low. This indicates that the bisphenol F epoxy / TDE-85 / AG-80 epoxy system prepared in Example 3 has excellent thermal stability and strong molecular chain thermal stability.

[0029] Table 3. Test results of thermal stability of epoxy system samples prepared in the examples and comparative examples. The above results show that, compared with Comparative Examples 1 and 2, the bisphenol F epoxy / TDE-85 / AG-80 and bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy systems of the present invention have significantly improved thermal stability; compared with the bisphenol F epoxy / TDE-85 / AG-80 / naphthol epoxy system, the bisphenol F epoxy / TDE-85 / AG-80 epoxy system has significantly improved thermal stability, among which the epoxy system of Example 3 has the best thermal stability.

Claims

1. A high-temperature resistant epoxy system, characterized in that, The raw materials include the following components by weight: 5-35 parts of bisphenol F epoxy resin, 5-25 parts of trifunctional epoxy resin, 5-25 parts of tetrafunctional epoxy resin, 40-80 parts of curing agent, and 0.2-10 parts of accelerator.

2. The high-temperature resistant epoxy system according to claim 1, characterized in that, The raw materials include the following components by weight: 10-30 parts of bisphenol F epoxy resin, 10-20 parts of trifunctional epoxy resin, 10-20 parts of tetrafunctional epoxy resin, 50-70 parts of curing agent, and 0.5-2 parts of accelerator.

3. The high-temperature resistant epoxy system according to claim 2, characterized in that, The raw materials include the following components by weight: 20 parts bisphenol F epoxy resin, 20 parts trifunctional epoxy resin, 20 parts tetrafunctional epoxy resin, 60 parts curing agent, and 1 part accelerator.

4. The high-temperature resistant epoxy system according to claim 1, characterized in that, It also includes the following raw materials by weight: 10-15 parts of naphthol-type epoxy resin.

5. The high-temperature resistant epoxy system according to claim 4, characterized in that, The raw materials include the following components by weight: 10 parts bisphenol F epoxy resin, 20 parts trifunctional epoxy resin, 10 parts tetrafunctional epoxy resin, 10 parts naphthol-type epoxy resin, 60 parts curing agent, and 1 part accelerator.

6. The high-temperature resistant epoxy system according to any one of claims 1 to 5, characterized in that, The trifunctional epoxy resin is selected from at least one of 4,5-epoxyhexane-1,2-dicarboxylic acid diglycidyl ester, N,N-diglycidyl-p-glycidyloxyaniline, and N,N-diglycidyl-4-glycidyloxyaniline; the tetrafunctional epoxy resin is selected from at least one of 4,4'-diaminodiphenylmethane tetraglycidylamine, 4,4'-diaminodiphenylsulfone tetraglycidylamine, m-phenylenediamine tetraglycidylamine, and pyromellitic tetraglycidyl ester; the curing agent is a cyclic anhydride compound; and the accelerator is an imidazole compound.

7. The high-temperature resistant epoxy system according to claim 6, characterized in that, The cyclic anhydride compounds are selected from at least one of methylnadic anhydride, nadic anhydride, and methylbicyclo-2,2,1-heptane-2,3-dicarboxylic anhydride; the imidazole compounds are selected from at least one of 2-ethyl-4-methylimidazolium, 2-isopropyl-4-methylimidazolium, 2-butyl-4-methylimidazolium, 1-benzyl-2-methylimidazolium, and 2-phenyl-4-methylimidazolium.

8. A method for preparing the high-temperature resistant epoxy system according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Weigh the raw materials according to their weight components, and then melt and blend them together to obtain a molten liquid; (2) After stirring the molten liquid evenly, remove the air bubbles under vacuum, then pour it into a preheated mold, and heat it up to solidify according to the set program to obtain the solidified product.

9. The method for preparing the high-temperature resistant epoxy system according to claim 8, characterized in that, The temperature for melt blending is 70~90℃; the temperature for vacuum degassing is 70~90℃; the temperature for curing is set sequentially as 90~110℃ / 1~3h, 120~160℃ / 1~3h, and 170~200℃ / 2~5h.

10. Use of the high-temperature resistant epoxy system according to any one of claims 1 to 7 in sealing materials.

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