High-temperature-resistant epoxy resin composite material as well as preparation method and application thereof

Abstract

The invention provides a high-temperature-resistant epoxy resin composite material as well as a preparation method and application thereof, and belongs to the technical field of composite materials. Flaky hexagonal boron nitride, boron nitride whiskers and silane coupling agent modified montmorillonite are adopted as filler, the flaky hexagonal boron nitride is of a two-dimensional flaky structure, a physical isolation layer can be formed after the flaky hexagonal boron nitride is dispersed into an epoxy resin matrix, the diffusion path of small-molecule decomposition products, oxygen and heat at high temperature is prolonged, and the thermal conductivity of the epoxy resin is improved; the boron nitride crystal whiskers have one-dimensional crystal whisker structures and can be inserted between the flaky hexagonal boron nitride lamellas and the epoxy resin matrix to play a pinning role, the lamellar structures and the matrix are firmly connected together, the lamellar structures are prevented from slipping under thermal stress, and the thermal oxidation degradation process of the epoxy resin is delayed; flaky montmorillonite in silane coupling agent modified montmorillonite has an excellent isolation effect and can fill lamellar gaps, and the three components have a synergistic effect, so that the high temperature resistance of the composite material is further improved.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, specifically relating to a high-temperature resistant epoxy resin composite material, its preparation method, and its application. Background Technology

[0002] With the increasing demand for electricity, higher and higher requirements are being placed on the transmission capacity, stability, and safety of power transmission systems. In high-voltage direct current (HVDC) transmission systems, bushings are key components connecting the inside and outside of substations, and their performance directly affects the stability and safety of the entire transmission system. Epoxy resin, due to its excellent insulation properties, mechanical strength, and chemical corrosion resistance, is increasingly widely used in power equipment, especially in HVDC transmission systems, where encapsulating bushings with epoxy materials can effectively improve system stability and reliability. Current epoxy resin encapsulation materials for bushings mainly consist of epoxy resin, curing agent, accelerator, and filler. Commonly used fillers include montmorillonite and mica powder, but the high-temperature resistance of existing epoxy resin materials still needs further improvement. Summary of the Invention

[0003] The purpose of this invention is to provide a high-temperature resistant epoxy resin composite material, its preparation method, and its application. The epoxy resin composite material provided by this invention has higher high-temperature resistance.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a high-temperature resistant epoxy resin composite material, which is prepared from the following raw materials in parts by weight: 80-100 parts epoxy resin, 100-120 parts curing agent, 1-10 parts accelerator, 1-5 parts filler and 0-1 parts additive; the filler includes plate-like hexagonal boron nitride, boron nitride whiskers and silane coupling agent modified montmorillonite.

[0005] Preferably, the epoxy resin comprises one or more of bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarbamate, and bis(7-oxabicyclo[4.1.0]3-heptylmethyl)adipate.

[0006] Preferably, the accelerator comprises N,N-dimethylbenzylamine and / or 2,4,6-tris(dimethylaminomethyl)phenol.

[0007] Preferably, the mass ratio of plate-like hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite in the filler is (1~3):(0.5~1):1.

[0008] Preferably, the sheet diameter of the plate-shaped hexagonal boron nitride is 1~5μm; the sheet thickness of the plate-shaped hexagonal boron nitride is ≤50nm.

[0009] Preferably, the diameter of the boron nitride whisker is 0.2~1μm; the length of the boron nitride whisker is 10~50μm.

[0010] Preferably, the montmorillonite sheets in the silane coupling agent modified montmorillonite have a thickness of 1~10 nm and a sheet diameter of 100~500 nm.

[0011] Preferably, the additives include defoamers.

[0012] The present invention also provides a method for preparing the high-temperature resistant epoxy resin composite material described above, comprising: mixing epoxy resin, curing agent, accelerator, filler and additives, and curing to obtain the high-temperature resistant epoxy resin composite material.

[0013] The present invention also provides the application of the high-temperature resistant epoxy resin composite material described in the above technical solution or the high-temperature resistant epoxy resin composite material prepared by the preparation method described in the above technical solution in epoxy resin impregnated synthetic fiber sleeves.

[0014] This invention provides a high-temperature resistant epoxy resin composite material, which is prepared from the following raw materials in parts by weight: 80-100 parts epoxy resin, 100-120 parts curing agent, 1-10 parts accelerator, 1-5 parts filler and 0-1 parts additive; the filler includes plate-like hexagonal boron nitride, boron nitride whiskers and silane coupling agent modified montmorillonite. This invention uses lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent-modified montmorillonite as fillers to improve the high-temperature resistance of epoxy resin. The lamellar hexagonal boron nitride has a two-dimensional lamellar structure, which, after being dispersed in the epoxy resin matrix, forms a physical isolation layer, prolonging the diffusion path of small molecule decomposition products, oxygen, and heat at high temperatures, and delaying the thermal oxidative degradation process of the epoxy resin. The boron nitride whiskers have a one-dimensional whisker structure, which can intersect between the lamellar hexagonal boron nitride sheets and the epoxy resin matrix, acting as a pinning agent to firmly connect the sheet structure to the matrix and prevent the sheets from slipping under thermal stress. The lamellar montmorillonite in the silane coupling agent-modified montmorillonite has excellent isolation properties, and its sheet diameter is smaller than that of the lamellar hexagonal boron nitride, which can fill the gaps in the sheets to form a denser isolation layer. The three components have a synergistic effect, further improving the high-temperature resistance of the composite material. Detailed Implementation

[0015] This invention provides a high-temperature resistant epoxy resin composite material, which is prepared from the following raw materials in parts by weight: 80-100 parts epoxy resin, 100-120 parts curing agent, 1-10 parts accelerator, 1-5 parts filler and 0-1 parts additive; the filler includes plate-like hexagonal boron nitride, boron nitride whiskers and silane coupling agent modified montmorillonite.

[0016] Unless otherwise specified, the present invention does not impose any special restrictions on the source of the raw materials, and commercially available products well known to those skilled in the art can be used.

[0017] The raw materials for preparing the high-temperature resistant epoxy resin composite material of the present invention, by weight, include 80-100 parts of epoxy resin. As one embodiment, the amount of epoxy resin used can be specifically 80 parts, 82 parts, 85 parts, 88 parts, 90 parts, 92 parts, 95 parts, 98 parts, or 100 parts.

[0018] In this invention, the epoxy resin preferably includes one or more of bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarbamate, and bis(7-oxabicyclo[4.1.0]3-heptylmethyl)adipate.

[0019] The raw materials for preparing the high-temperature resistant epoxy resin composite material of the present invention further include 100-120 parts of curing agent, based on 80-100 parts by weight of epoxy resin. As one embodiment, the amount of curing agent can be specifically 100 parts, 102 parts, 105 parts, 108 parts, 110 parts, 112 parts, 115 parts, 118 parts, or 120 parts.

[0020] In this invention, the curing agent is preferably prepared from an acid anhydride curing agent and a diamine compound.

[0021] In an embodiment of the present invention, the curing agent is prepared as follows: (1) 1,4-diaminobutane and 4,4′-biphenyl ether dianhydride are placed in a drying oven and dried at 80°C for 5 hours to obtain dried 1,4-diaminobutane and 4,4′-biphenyl ether dianhydride; (2) 30g of 1,4-diaminobutane and 150mL of N,N-dimethylformamide are stirred at a rate of 250r / min for 30 minutes to obtain a diamine compound solution; 70g of 4,4′-biphenyl ether dianhydride and 150mL of N,N-dimethylformamide are stirred at a rate of 250r / min for 30 minutes to obtain a diamine compound solution; N,N-dimethylformamide was stirred at a rate of 250 r / min for 30 min to obtain an anhydride curing agent solution; (3) anhydrous magnesium sulfate desiccant was added to the anhydride curing agent solution, and the mixture was placed in a four-necked flask and heated and stirred at 65°C at a stirring rate of 250 r / min. The diamine compound solution was added dropwise to the anhydride curing agent solution at a rate of 10 mL / min, and the crosslinking reaction time was controlled to be 2 h; (4) after the reaction was completed, the anhydrous magnesium sulfate was filtered by vacuum filtration to obtain a solution containing the curing agent after the reaction. The solution was placed in a drying oven and dried at 120°C for 12 h to obtain the curing agent. The curing agent used in this invention has a rigid-flexible-rigid structure, which can further improve the high temperature resistance of epoxy resin composite materials.

[0022] The raw materials for preparing the high-temperature resistant epoxy resin composite material of the present invention further include 1 to 10 parts of accelerator, based on 80 to 100 parts by weight of epoxy resin. As one embodiment, the amount of accelerator may specifically be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts.

[0023] In this invention, the accelerator preferably includes N,N-dimethylbenzylamine and / or 2,4,6-tris(dimethylaminomethyl)phenol.

[0024] The raw materials for preparing the high-temperature resistant epoxy resin composite material of the present invention further include 1 to 5 parts of filler, based on an epoxy resin weight of 80 to 100 parts. As one embodiment, the amount of filler may specifically be 1 part, 2 parts, 3 parts, 4 parts, or 5 parts.

[0025] In this invention, the filler comprises plate-like hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite.

[0026] In this invention, the sheet diameter of the plate-shaped hexagonal boron nitride is preferably 1~5μm; the sheet thickness of the plate-shaped hexagonal boron nitride is preferably ≤50nm.

[0027] In this invention, the diameter of the boron nitride whisker is preferably 0.2~1μm; the length of the boron nitride whisker is preferably 10~50μm.

[0028] In this invention, the thickness of the montmorillonite sheets in the silane coupling agent modified montmorillonite is preferably 1~10 nm; the diameter of the montmorillonite sheets in the silane coupling agent modified montmorillonite is preferably 100~500 nm.

[0029] As one implementation method, the silane coupling agent in the silane coupling agent modified montmorillonite may specifically be KH560.

[0030] The present invention does not impose any special limitations on the preparation method of the silane coupling agent modified montmorillonite; any technical solution known to those skilled in the art can be used.

[0031] In an embodiment of the present invention, the preparation method of the silane coupling agent modified montmorillonite is as follows: ethanol and water are mixed at a volume ratio of 7:3, the pH is adjusted to 5 using acetic acid, silane coupling agent KH560 is added, and the mixture is stirred for 1.5 h to obtain a silane coupling agent solution (the mass concentration of the silane coupling agent in the silane coupling agent solution is 1%); the silane coupling agent solution is mixed with montmorillonite (the mass ratio of the silane coupling agent to montmorillonite in the silane coupling agent solution is 0.2:1), and the mixture is stirred at 75°C for 5 h. After the reaction is completed, the mixture is cooled to room temperature, filtered, washed with an ethanol-water solution (the volume ratio of ethanol to water is 7:3), and dried to obtain the silane coupling agent modified montmorillonite.

[0032] In this invention, the preferred mass ratio of the lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent-modified montmorillonite is (1~3):(0.5~1):1. As one embodiment, the mass ratio of the lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent-modified montmorillonite can be specifically 1:1:1, 2:1:1, or 3:1:1. By controlling the mass ratio of the lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent-modified montmorillonite within the above range, this invention can further improve the high-temperature resistance of the composite material.

[0033] The raw materials for preparing the high-temperature resistant epoxy resin composite material of the present invention further include 0-1 parts of additives, based on an epoxy resin weight of 80-100 parts.

[0034] In this invention, the additives preferably include defoamers. This invention does not impose any particular limitation on the type of defoamer; any defoamer well-known to those skilled in the art can be used.

[0035] This invention uses lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent-modified montmorillonite as fillers to improve the high-temperature resistance of epoxy resin. The lamellar hexagonal boron nitride has a two-dimensional lamellar structure, which, after being dispersed in the epoxy resin matrix, forms a physical isolation layer, prolonging the diffusion path of small molecule decomposition products, oxygen, and heat at high temperatures, and delaying the thermal oxidative degradation process of the epoxy resin. The boron nitride whiskers have a one-dimensional whisker structure, which can intersect between the lamellar hexagonal boron nitride sheets and the epoxy resin matrix, acting as a pinning agent to firmly connect the sheet structure to the matrix and prevent the sheets from slipping under thermal stress. The lamellar montmorillonite in the silane coupling agent-modified montmorillonite has excellent isolation properties, and its sheet diameter is smaller than that of the lamellar hexagonal boron nitride, which can fill the gaps in the sheets to form a denser isolation layer. The three components have a synergistic effect, and compared to adding one or two of them alone, they can further improve the high-temperature resistance of the composite material.

[0036] The present invention also provides a method for preparing the high-temperature resistant epoxy resin composite material described above, comprising: mixing epoxy resin, curing agent, accelerator, filler and additives, and curing to obtain the high-temperature resistant epoxy resin composite material.

[0037] The present invention does not impose any special limitations on the mixing method of the epoxy resin, curing agent, accelerator, filler and additives, as long as the raw materials are mixed evenly.

[0038] In this invention, the curing preferably includes a first curing and a second curing performed sequentially; the temperature of the first curing is preferably 100~120℃; the time of the first curing is preferably 4~6h; the temperature of the second curing is preferably 150~170℃; and the time of the second curing is preferably 12~15h. By controlling the curing parameters within the above ranges, this invention ensures sufficient curing and further improves the high-temperature resistance of the composite material.

[0039] Because the amount of filler used in this invention is relatively small, and some of it is modified by silane coupling agent, high-temperature resistant epoxy resin composite material can be prepared without adding organic solvent.

[0040] The present invention also provides the application of the high-temperature resistant epoxy resin composite material described in the above technical solution or the high-temperature resistant epoxy resin composite material prepared by the preparation method described in the above technical solution in epoxy resin impregnated synthetic fiber sleeves.

[0041] The present invention does not impose any special limitations on the operation of the application, and any technical solution known to those skilled in the art can be used.

[0042] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0043] Example 1 A high-temperature resistant epoxy resin composite material is prepared from the following raw materials in parts by weight: 100 parts of epoxy resin (3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarbamate), 100 parts of curing agent, 2 parts of accelerator (N,N-dimethylbenzylamine) and 3 parts of filler. The filler is composed of lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite; the mass ratio of the lamellar hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite is 2:1:1; the lamellar diameter of the lamellar hexagonal boron nitride is 1~5μm, and the lamellar thickness is ≤50nm; the diameter of the boron nitride whiskers is 0.2~1μm, and the length is 10~50μm; the montmorillonite in the silane coupling agent modified montmorillonite has a lamellar thickness of 1~10nm and a lamellar diameter of 100~500nm; The preparation method of the high temperature resistant epoxy resin composite material is as follows: (1) the epoxy resin, curing agent, accelerator and filler are dried at 80°C for 5 hours to obtain the dried epoxy resin, curing agent, accelerator and filler; (2) The dried epoxy resin and curing agent are stirred and mixed at 130°C for 30 min. Then, the accelerator is added and stirred and mixed at 130°C for 30 min under vacuum. Then, the filler is added and stirred evenly. Then, it is poured into a mold, cured at 100°C for 4 h, and then cured at 160°C for 12 h to obtain a high-temperature resistant epoxy resin composite material.

[0044] Example 2 The amount of filler used in Example 1 was replaced with 5 parts, and everything else was the same as in Example 1.

[0045] Comparative Example 1 The filler type in Example 2 was replaced with plate-shaped hexagonal boron nitride, and everything else was the same as in Example 2.

[0046] Comparative Example 2 The filler type in Example 2 was replaced with boron nitride whiskers, and everything else was the same as in Example 2.

[0047] Comparative Example 3 The filler type in Example 2 was replaced with silane coupling agent modified montmorillonite, and everything else was the same as in Example 2.

[0048] Comparative Example 4 The filler type in Example 2 was replaced with plate-shaped hexagonal boron nitride and silane coupling agent modified montmorillonite, with a mass ratio of plate-shaped hexagonal boron nitride to silane coupling agent modified montmorillonite of 3:1. All other aspects were the same as in Example 2.

[0049] The thermal decomposition temperature (T5%) of the composite materials in Examples 1-2 and Comparative Examples 1-4 was tested, and the results are shown in Table 1.

[0050] Table 1. Heat resistance properties of the composite materials in Examples 1-2 and Comparative Examples 1-4

[0051] As can be seen from the data in Table 1, the present invention uses plate-like hexagonal boron nitride, boron nitride whiskers and silane coupling agent modified montmorillonite as fillers, which can further improve the high temperature resistance of epoxy resin composite materials compared with adding one or two of them alone.

[0052] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature resistant epoxy resin composite material, prepared from raw materials comprising the following parts by weight: 80-100 parts epoxy resin, 100-120 parts curing agent, 1-10 parts accelerator, 1-5 parts filler, and 0-1 parts additive; wherein the filler comprises flake hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite.

2. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The epoxy resin includes one or more of bisphenol A diglycidyl ether, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarbamate, and bis(7-oxabicyclo[4.1.0]3-heptylmethyl)adipate.

3. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The accelerator includes N,N-dimethylbenzylamine and / or 2,4,6-tris(dimethylaminomethyl)phenol.

4. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The mass ratio of the filler material to the plate-like hexagonal boron nitride, boron nitride whiskers, and silane coupling agent modified montmorillonite is (1~3):(0.5~1):

1.

5. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The sheet diameter of the hexagonal boron nitride is 1~5μm; the sheet thickness of the hexagonal boron nitride is ≤50nm.

6. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The diameter of the boron nitride whiskers is 0.2~1μm; the length of the boron nitride whiskers is 10~50μm.

7. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The montmorillonite sheets modified with the silane coupling agent have a thickness of 1-10 nm and a diameter of 100-500 nm.

8. The high-temperature resistant epoxy resin composite material according to claim 1, characterized in that, The additives include defoamers.

9. The method for preparing the high-temperature resistant epoxy resin composite material according to any one of claims 1 to 8 comprises: Epoxy resin, curing agent, accelerator, filler and additives are mixed and cured to obtain a high-temperature resistant epoxy resin composite material.

10. The application of the high-temperature resistant epoxy resin composite material according to any one of claims 1 to 8 or the high-temperature resistant epoxy resin composite material prepared by the preparation method according to claim 9 in epoxy resin impregnated synthetic fiber sleeves.

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