CN112266574A - Epoxy resin composite material and preparation method thereof - Google Patents
Epoxy resin composite material and preparation method thereof Download PDFInfo
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- CN112266574A CN112266574A CN202011018883.0A CN202011018883A CN112266574A CN 112266574 A CN112266574 A CN 112266574A CN 202011018883 A CN202011018883 A CN 202011018883A CN 112266574 A CN112266574 A CN 112266574A
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L63/00—Compositions of epoxy resins; Compositions of derivatives of epoxy resins
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Abstract
The invention provides an epoxy resin composite material and a preparation method thereof, wherein the epoxy resin composite material comprises 2.5-10 parts of monohydroxy polyether alcohol grafted epoxy resin, 100 parts of epoxy resin, 60-100 parts of curing agent and 1 part of accelerator by mass, the tensile strength of the epoxy resin composite material prepared by the method is up to 85MPa, the bending strength of the epoxy resin composite material is up to 135MPa, the epoxy resin composite material does not crack when the temperature is reduced to minus 60 ℃, and the packaging requirements of electrical equipment such as high-frequency transformers and the like are greatly met.
Description
Technical Field
The invention relates to an insulating packaging material, in particular to an epoxy resin composite material and a preparation method thereof.
Background
With the wide access of direct-current power supplies such as distributed power supplies, novel energy storage devices, fuel cells and micro-grids and the wide application of direct-current loads such as electric automobiles, data centers, computers and urban rail transit, the traditional power distribution network needs to have the capacity of both alternating-current power supply access and direct-current power supply access and alternating-current and direct-current load power supply; on the other hand, due to the popularization of the distributed power generation technology, the traditional power distribution system expands the power generation function from a single power supply form, energy flows from the traditional source, network and load in a one-way mode to the two-way flow mode, and the power distribution network is required to have the regional energy coordination control capability.
The high-capacity high-frequency transformer is a key component in an alternating current-direct current hybrid power distribution network and plays key roles in electrical isolation, voltage transformation, power transmission and the like. In order to meet the overall requirements of system floor space, energy conservation, environmental protection, safety, reliability, convenience in maintenance and the like, the high-frequency transformer serving as indoor equipment not only needs to undertake the task of high-voltage electrical isolation between high-voltage and low-voltage systems, but also has the advantages of small volume, high power density and efficiency and convenience in maintenance and repair. The high-frequency transformer adopts the insulating mode of full epoxy solid seal, can effectively reduce the insulating distance between the high-low pressure of transformer, further reduces the volume of transformer, can avoid the big problem of the fire prevention design degree of difficulty that conventional oil insulation brought simultaneously.
At present, the popularization and application of the full epoxy sealing technology in the high-frequency transformer have the following problems: the high-frequency transformer has complex operation working conditions, needs an insulating material to meet various requirements such as tolerance performance, heat resistance performance, mechanical performance and the like, and particularly has higher cracking resistance. In the prior art, chinese patent with application number CN 102070873a proposes a toughened epoxy resin grouting material, which mainly comprises epoxy resin, reactive diluent, curing agent, accelerator and coupling agent. The toughness of the grouting material is improved to a certain extent by the aid of the diluent and the like, but the modification effect is limited due to physical blending mostly, and the toughness of the prepared epoxy material cannot meet the engineering requirement of slightly high tensile strength. The Chinese patent of CN 102924692A provides a polyurethane graft modified epoxy resin interpenetrating network polymer material, which adopts chemical bond connection to thoroughly solve the technical bottlenecks of poor toughening effect and the like caused by the conventional physical blending toughening agent. However, the polyurethane grafted epoxy resin material needs to be added with a diluent in the processing process, so that the dielectric loss is increased, and the polyurethane grafted epoxy resin material is not suitable for electrical casting epoxy materials. Chinese patent application No. CN 110144035a proposes a polyethylene glycol grafted epoxy resin composite material, MDI and PEG are prepared into a diblock copolymer, which is then grafted into epoxy resin to form a triblock copolymer. It has been found that the isocyanates of the two segments of the diblock copolymer react with the hydroxyl groups of the two epoxy molecules to form crosslinks, which leads to an increase in viscosity and creates great difficulties in the casting process.
Disclosure of Invention
In order to make up for the defects of the prior art, the invention discloses an epoxy resin composite material with high tensile strength, small viscosity, excellent anti-cracking performance and high toughness and a preparation method thereof, and the invention is realized by adopting the following technical scheme:
the epoxy resin composite material comprises the following components in parts by mass: 2.5-10 parts of monohydroxy polyether alcohol grafted epoxy resin, 100 parts of epoxy resin, 60-100 parts of curing agent and 1 part of accelerator;
the tensile strength of the composite material is 78-85MPa, the bending strength is 121-135MPa, and the cracking resistance temperature is less than-60 ℃.
Further, the monohydroxy polyether alcohol grafted epoxy resin comprises the following components in parts by mass: 10-15 parts of monohydroxy polyether alcohol, 10-20 parts of bifunctional isocyanate, 10-30 parts of bisphenol A epoxy resin, 450-500 parts of solvent and 0.01-0.05 part of catalyst.
Further, the monohydroxy polyether alcohol comprises polyethylene glycol monomethyl ether, polyethylene glycol monobutyl ether or polyethylene glycol monoallyl ether;
the weight average molecular weight of the monohydroxy polyether alcohol is 300-5000.
Further, the difunctional isocyanate includes toluene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, trimethylhexamethylene diisocyanate, 4' -diphenylmethane diisocyanate or hexamethylene diisocyanate.
Further, the catalyst comprises: an organic bismuth-based catalyst or an organic tin-based catalyst.
Further, the solvent includes tetrahydrofuran, toluene, or N, N-dimethylformamide.
Further, the epoxy resin comprises the following components: bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, or epoxy resin having a hydroxyl group in a side chain; the curing agent comprises phthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or pyromellitic anhydride; the accelerator comprises benzyldimethylamine, imidazole or imidazole derivatives.
Further, the epoxy resin is preferably bisphenol a type epoxy resin; the curing agent is preferably hexahydrophthalic anhydride; the promoter is preferably benzyldimethylamine.
The preparation method of the epoxy resin composite material comprises the following steps:
1) preheating the die and mixing the curing agent and the epoxy resin;
2) at 50-120 deg.C, -5.5X 104～-1.1×104Stirring the mixture obtained in the step 1) under Pa for 10-180 min;
3) at-5.5X 104～-1.1×104And Pa lower casting a mold, and solidifying the mixture obtained in the step 2) in a segmented manner at 50-180 ℃ to obtain the epoxy composite material.
Further, the step 3) of segmented curing comprises the following steps: heating the mixture obtained in the step 2) at the temperature of 100 ℃ and 120 ℃ for 3-5h, and then heating at the temperature of 140 ℃ and 170 ℃ for 12-16 h.
Compared with the closest prior art, the technical scheme provided by the invention has the following beneficial effects:
1) according to the technical scheme provided by the invention, the flexible monohydroxy polyether chain is connected to the epoxy resin branched chain through the isocyanate, so that the toughness of the epoxy composite material is greatly improved, the tensile strength of the epoxy composite material can reach 85MPa at most, the bending strength of the epoxy composite material can reach 135MPa, the epoxy composite material is not cracked when being cooled to minus 60 ℃, and the packaging requirements of electrical equipment such as a high-frequency transformer and the like are greatly met.
2) According to the technical scheme provided by the invention, the molecular weight of the monohydroxy ether chain is 500-5000, the toughness of the composite material can be effectively changed by adjusting the molecular weight of the branched chain, and meanwhile, as the polyether alcohol chain is a single functional group, the cross-linking with an epoxy resin body is avoided, and the viscosity of the material is greatly reduced.
3) The technical scheme provided by the invention has the advantages that the compatibility of the single-hydroxy ether chain grafted epoxy resin and the basic epoxy resin is better, the phase separation phenomenon caused by physical blending is effectively avoided, and the resistivity of the epoxy resin composite material provided by the invention at 30 ℃ is 1.9 multiplied by 1017-4.0×1017Omega cm, dielectric loss of only 3 x 10-3。
Detailed Description
The following further description of the present invention is provided for a better understanding of the present invention.
The monohydroxy polyether alcohol provided by the invention comprises polyethylene glycol monomethyl ether, polyethylene glycol monobutyl ether or polyethylene glycol monoallyl ether; wherein the weight average molecular weight of the monohydroxy polyether alcohol is 300-5000; the difunctional isocyanate comprises toluene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, trimethylhexamethylene diisocyanate, 4' -diphenylmethane diisocyanate or hexamethylene diisocyanate; the catalyst comprises: an organic bismuth-based catalyst or an organic tin-based catalyst; the solvent comprises tetrahydrofuran, toluene or N, N-dimethylformamide; the epoxy resin comprises the following components: bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, or epoxy resin having a hydroxyl group in a side chain; the curing agent comprises phthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or pyromellitic anhydride; the accelerator comprises benzyldimethylamine, imidazole or imidazole derivatives.
Example 1
The preparation method of the epoxy resin composite material provided by the embodiment comprises the following steps:
1) preparation of monohydroxy polyether alcohol grafted epoxy resin
Adding 10 parts by mass of Toluene Diisocyanate (TDI), 0.01 part by mass of dibutyltin dilaurate and 10 parts by mass of polyethylene glycol monomethyl ether-550 into 450 parts by mass of Tetrahydrofuran (THF), uniformly mixing, reacting at 60 ℃ for 4 hours, then adding 10 parts by mass of bisphenol A type epoxy resin (epoxy value is 0.54), uniformly mixing, continuously reacting for 4 hours, and removing the solvent to obtain the monohydroxy polyether alcohol grafted epoxy resin.
2) Preparation of epoxy resin composite
2.5 parts by mass of monohydroxy polyether alcohol grafted epoxy resin, 100 parts by mass of bisphenol A epoxy resin, 100 parts by mass of hexahydrophthalic anhydride curing agent and 1 part by mass of promoter Benzyl Dimethylamine (BDMA) are added into a preheated mold, and the mixed solution is heated to 50 ℃ and heated to-5.5 multiplied by 104Stirring for 180min under Pa environment, pouring into a mold under the same pressure, and heating and curing at 100 deg.C and 140 deg.C for 3h and 12h respectively. And obtaining the epoxy resin composite material.
Example 2
The preparation method of the epoxy resin composite material provided by the embodiment comprises the following steps:
1) preparation of monohydroxy polyether alcohol grafted epoxy resin
Adding 15 parts by mass of Toluene Diisocyanate (TDI), 0.02 part by mass of dibutyltin dilaurate and 12 parts by mass of polyethylene glycol monomethyl ether-550 into 460 parts by mass of Tetrahydrofuran (THF), uniformly mixing, reacting at 60 ℃ for 4 hours, then adding 15 parts by mass of bisphenol A type epoxy resin (epoxy value is 0.54), uniformly mixing, continuously reacting for 4 hours, and removing the solvent to obtain the monohydroxy polyether alcohol grafted epoxy resin.
2) Preparation of epoxy resin composite
Adding 5 parts by mass of monohydroxy polyether alcohol grafted epoxy resin, 100 parts by mass of bisphenol A epoxy resin, 60 parts by mass of hexahydrophthalic anhydride curing agent and 1 part by mass of promoter Benzyl Dimethylamine (BDMA) into a preheated mold, and heating the mixed solution to 70 ℃ at the temperature of-1.8 multiplied by 104Stirring for 2h under Pa environment, pouring into a mold under the same pressure, and heating and curing at 110 deg.C and 150 deg.C for 4h and 14h respectively. And obtaining the epoxy resin composite material.
Example 3
The preparation method of the epoxy resin composite material provided by the embodiment comprises the following steps:
1) preparation of monohydroxy polyether alcohol grafted epoxy resin
Adding 15 parts by mass of Toluene Diisocyanate (TDI), 0.03 part by mass of dibutyltin dilaurate and 14 parts by mass of polyethylene glycol monomethyl ether-550 into 480 parts by mass of Tetrahydrofuran (THF), uniformly mixing, reacting at 60 ℃ for 4 hours, then adding 25 parts by mass of bisphenol A type epoxy resin (epoxy value is 0.54), uniformly mixing, continuously reacting for 4 hours, and removing the solvent to obtain the monohydroxy polyether alcohol grafted epoxy resin.
2) Preparation of epoxy resin composite
Mixing 8 parts by mass of monohydroxy polyether alcohol grafted epoxy resin, 100 parts by mass of bisphenol A type epoxy resin, 80 parts by mass of hexahydrophthalic anhydride curing agent and 1 part by mass of promoter Benzyl Dimethylamine (BDMA), heating to 100 ℃, and carrying out heating at-3.2 x 104Stirring for 2h in a Pa environment, pouring into a mold under the same pressure, and heating and curing at 110 ℃ and 160 ℃ for 4h and 15h respectively. And obtaining the epoxy resin composite material.
Example 4
The preparation method of the epoxy resin composite material provided by the embodiment comprises the following steps:
1) preparation of monohydroxy polyether alcohol grafted epoxy resin
Adding 20 parts by mass of Hexamethylene Diisocyanate (HDI), 0.05 part by mass of dibutyltin dilaurate and 15 parts by mass of polyethylene glycol monomethyl ether-550 into 500 parts by mass of Tetrahydrofuran (THF), uniformly mixing, reacting at 60 ℃ for 4 hours, then adding 30 parts by mass of bisphenol A type epoxy resin (epoxy value is 0.54), uniformly mixing, continuously reacting for 4 hours, and removing the solvent to obtain the monohydroxy polyether alcohol grafted epoxy resin.
2) Preparation of high-toughness epoxy resin composite material
Taking 10 parts by mass of monohydroxy polyether alcohol grafted epoxy resin, 100 parts by mass of bisphenol A type epoxy resin, 100 parts by mass of hexahydrophthalic anhydride curing agent and 1 part by mass of promoter Benzyl Dimethylamine (BDMA), heating the mixed solution to 120 ℃, and controlling the temperature at-1.1 multiplied by 104Stirring for 10min under Pa, pouring into a mold under the same pressure, and heating and curing at 120 ℃ and 170 ℃ for 5h and 16h respectively.And obtaining the epoxy resin composite material.
Comparative example 1
The preparation method of the cured base epoxy resin provided by the comparative example comprises the following steps:
100 parts by mass of bisphenol A epoxy matrix, 100 parts by mass of hexahydrophthalic anhydride curing agent and 1 part by mass of accelerator BDMA are mixed and heated to 70 ℃ and the pressure is 1.8 multiplied by 104Stirring under vacuum for 2h in Pa environment, pouring into a mold under the same negative pressure, and heating and curing at 80 deg.C and 130 deg.C for 4h and 12h respectively.
Performance testing
The performance test method of the epoxy resin material of the embodiment and the comparative example comprises the following steps:
the Direct Current (DC) volume resistivity (ρ v) of the epoxy samples was measured using a Keithley 6517B high resistivity meter and a Keithley 8009 sample holder, using a 1mm thick circular disc. The test voltage was 1000V.
The thermal conductivity of the epoxy samples was measured using a C-Therm TCi thermal conductivity analyzer using a transient planar heat source (MTPS) method. The samples used were discs with a thickness of 3 mm.
The epoxy samples were tested for tensile and flexural strength using a CMT6104 universal tester. The samples used were dumbbell-shaped and strip-shaped samples in accordance with the respective test standards, with a thickness of 4 mm.
The viscosity of the epoxy resin, curing agent system was tested using an HAAKETM MARSTM III rotational rheometer. The samples were tested for viscosity change at 30 ℃ using a parallel plate construction rotor.
The performance test results of the embodiment and the comparative example of the invention are shown in Table 1, the obtained epoxy resin material has the tensile strength of 78-85MPa, the bending strength of 121-135MPa, the cracking resistance temperature of less than-60 ℃, the insulating property is good, the dielectric loss is only 0.00215 at the lowest, and the encapsulating requirements of electrical equipment such as high-frequency transformers and the like can be met.
TABLE 1 results of property test of insulating materials obtained in examples of the present invention and comparative examples
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the scope of the claims of the present invention which are filed as the application.
Claims (10)
1. The epoxy resin composite material is characterized by comprising the following components in parts by mass: 2.5-10 parts of monohydroxy polyether alcohol grafted epoxy resin, 100 parts of epoxy resin, 60-100 parts of curing agent and 1 part of accelerator;
the tensile strength of the composite material is 78-85MPa, the bending strength is 121-135MPa, and the cracking resistance temperature is less than-60 ℃.
2. The epoxy resin composite material according to claim 1, wherein the monohydroxy polyether alcohol graft epoxy resin comprises the following components in parts by mass: 10-15 parts of monohydroxy polyether alcohol, 10-20 parts of bifunctional isocyanate, 10-30 parts of bisphenol A epoxy resin, 450-500 parts of solvent and 0.01-0.05 part of catalyst.
3. The epoxy resin composite of claim 2, wherein the monohydroxy polyether alcohol comprises polyethylene glycol monomethyl ether, polyethylene glycol monobutyl ether, or polyethylene glycol monoallyl ether;
the weight average molecular weight of the monohydroxy polyether alcohol is 300-5000.
4. The epoxy resin composite of claim 2, wherein the difunctional isocyanate comprises toluene diisocyanate, isophorone diisocyanate, p-phenylene diisocyanate, trimethylhexamethylene diisocyanate, 4' -diphenylmethane diisocyanate, or hexamethylene diisocyanate.
5. The epoxy composite of claim 2, wherein the catalyst comprises: an organic bismuth-based catalyst or an organic tin-based catalyst.
6. The epoxy composite of claim 2, wherein the solvent comprises tetrahydrofuran, toluene, or N, N-dimethylformamide.
7. The epoxy resin composite of claim 1, wherein the epoxy resin comprises: bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, or epoxy resin having a hydroxyl group in a side chain; the curing agent comprises phthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride or pyromellitic anhydride; the accelerator comprises benzyldimethylamine, imidazole or imidazole derivatives.
8. The epoxy resin composite according to claim 7, wherein the epoxy resin is preferably a bisphenol a type epoxy resin; the curing agent is preferably hexahydrophthalic anhydride; the promoter is preferably benzyldimethylamine.
9. A process for the preparation of an epoxy resin composite according to any one of claims 1 to 7, characterized in that it comprises the following steps:
1) preheating the die and mixing the curing agent and the epoxy resin;
2) at 50-120 deg.C, -5.5X 104～-1.1×104Stirring the mixture obtained in the step 1) under Pa for 10-180 min;
3) at-5.5X 104～-1.1×104And Pa lower casting a mold, and solidifying the mixture obtained in the step 2) in a segmented manner at 50-180 ℃ to obtain the epoxy composite material.
10. The method of preparing an epoxy resin composite material according to claim 9, wherein the step 3) of stepwise curing comprises: heating the mixture obtained in the step 2) at the temperature of 100 ℃ and 120 ℃ for 3-5h, and then heating at the temperature of 140 ℃ and 170 ℃ for 12-16 h.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011018883.0A CN112266574A (en) | 2020-09-24 | 2020-09-24 | Epoxy resin composite material and preparation method thereof |
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| CN202011018883.0A CN112266574A (en) | 2020-09-24 | 2020-09-24 | Epoxy resin composite material and preparation method thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114292498A (en) * | 2022-02-22 | 2022-04-08 | 陕西理工大学 | Preparation method of lycopodium clavatum powder-epoxy resin waterproof composite material |
-
2020
- 2020-09-24 CN CN202011018883.0A patent/CN112266574A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114292498A (en) * | 2022-02-22 | 2022-04-08 | 陕西理工大学 | Preparation method of lycopodium clavatum powder-epoxy resin waterproof composite material |
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Effective date of registration: 20211012 Address after: 102209 18 Riverside Avenue, Changping District science and Technology City, Beijing Applicant after: GLOBAL ENERGY INTERCONNECTION RESEARCH INSTITUTE Co.,Ltd. Applicant after: STATE GRID SHANGHAI MUNICIPAL ELECTRIC POWER Co. Address before: 102209 18 Riverside Avenue, Changping District science and Technology City, Beijing Applicant before: GLOBAL ENERGY INTERCONNECTION RESEARCH INSTITUTE Co.,Ltd. |
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