CN116285226A - Epoxy resin composition with low-temperature conductivity activation energy, preparation method and application - Google Patents
Epoxy resin composition with low-temperature conductivity activation energy, preparation method and application Download PDFInfo
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- CN116285226A CN116285226A CN202310039803.7A CN202310039803A CN116285226A CN 116285226 A CN116285226 A CN 116285226A CN 202310039803 A CN202310039803 A CN 202310039803A CN 116285226 A CN116285226 A CN 116285226A
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- 239000003822 epoxy resin Substances 0.000 title claims abstract description 145
- 229920000647 polyepoxide Polymers 0.000 title claims abstract description 145
- 239000000203 mixture Substances 0.000 title claims abstract description 88
- 230000004913 activation Effects 0.000 title claims abstract description 39
- 238000002360 preparation method Methods 0.000 title abstract description 8
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 22
- 238000009826 distribution Methods 0.000 claims abstract description 20
- 230000005684 electric field Effects 0.000 claims abstract description 17
- 239000003607 modifier Substances 0.000 claims abstract description 11
- 238000005266 casting Methods 0.000 claims abstract description 8
- 238000007598 dipping method Methods 0.000 claims abstract description 5
- 239000011159 matrix material Substances 0.000 claims abstract description 4
- 239000012212 insulator Substances 0.000 claims abstract 4
- 239000004593 Epoxy Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 17
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- MWSKJDNQKGCKPA-UHFFFAOYSA-N 6-methyl-3a,4,5,7a-tetrahydro-2-benzofuran-1,3-dione Chemical compound C1CC(C)=CC2C(=O)OC(=O)C12 MWSKJDNQKGCKPA-UHFFFAOYSA-N 0.000 claims description 8
- 150000001412 amines Chemical class 0.000 claims description 7
- IISBACLAFKSPIT-UHFFFAOYSA-N bisphenol A Chemical compound C=1C=C(O)C=CC=1C(C)(C)C1=CC=C(O)C=C1 IISBACLAFKSPIT-UHFFFAOYSA-N 0.000 claims description 7
- 125000003700 epoxy group Chemical group 0.000 claims description 7
- YBRVSVVVWCFQMG-UHFFFAOYSA-N 4,4'-diaminodiphenylmethane Chemical compound C1=CC(N)=CC=C1CC1=CC=C(N)C=C1 YBRVSVVVWCFQMG-UHFFFAOYSA-N 0.000 claims description 6
- PLIKAWJENQZMHA-UHFFFAOYSA-N 4-aminophenol Chemical compound NC1=CC=C(O)C=C1 PLIKAWJENQZMHA-UHFFFAOYSA-N 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
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- 238000002156 mixing Methods 0.000 claims description 6
- MUTGBJKUEZFXGO-OLQVQODUSA-N (3as,7ar)-3a,4,5,6,7,7a-hexahydro-2-benzofuran-1,3-dione Chemical compound C1CCC[C@@H]2C(=O)OC(=O)[C@@H]21 MUTGBJKUEZFXGO-OLQVQODUSA-N 0.000 claims description 5
- 150000008064 anhydrides Chemical group 0.000 claims description 5
- -1 boron acyl halide amine Chemical class 0.000 claims description 5
- LTVUCOSIZFEASK-MPXCPUAZSA-N (3ar,4s,7r,7as)-3a-methyl-3a,4,7,7a-tetrahydro-4,7-methano-2-benzofuran-1,3-dione Chemical compound C([C@H]1C=C2)[C@H]2[C@H]2[C@]1(C)C(=O)OC2=O LTVUCOSIZFEASK-MPXCPUAZSA-N 0.000 claims description 4
- PXKLMJQFEQBVLD-UHFFFAOYSA-N bisphenol F Chemical compound C1=CC(O)=CC=C1CC1=CC=C(O)C=C1 PXKLMJQFEQBVLD-UHFFFAOYSA-N 0.000 claims description 4
- 229920005989 resin Polymers 0.000 claims description 4
- 239000011347 resin Substances 0.000 claims description 4
- MEVBAGCIOOTPLF-UHFFFAOYSA-N 2-[[5-(oxiran-2-ylmethoxy)naphthalen-2-yl]oxymethyl]oxirane Chemical compound C1OC1COC(C=C1C=CC=2)=CC=C1C=2OCC1CO1 MEVBAGCIOOTPLF-UHFFFAOYSA-N 0.000 claims description 3
- YXALYBMHAYZKAP-UHFFFAOYSA-N 7-oxabicyclo[4.1.0]heptan-4-ylmethyl 7-oxabicyclo[4.1.0]heptane-4-carboxylate Chemical compound C1CC2OC2CC1C(=O)OCC1CC2OC2CC1 YXALYBMHAYZKAP-UHFFFAOYSA-N 0.000 claims description 3
- 125000002723 alicyclic group Chemical group 0.000 claims description 3
- 125000003118 aryl group Chemical group 0.000 claims description 3
- 229910052796 boron Inorganic materials 0.000 claims description 3
- 150000003512 tertiary amines Chemical class 0.000 claims description 3
- 238000009849 vacuum degassing Methods 0.000 claims description 3
- 238000010907 mechanical stirring Methods 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 claims 1
- 238000010292 electrical insulation Methods 0.000 abstract description 3
- 238000009413 insulation Methods 0.000 description 18
- XXBDWLFCJWSEKW-UHFFFAOYSA-N dimethylbenzylamine Chemical compound CN(C)CC1=CC=CC=C1 XXBDWLFCJWSEKW-UHFFFAOYSA-N 0.000 description 17
- VYKXQOYUCMREIS-UHFFFAOYSA-N methylhexahydrophthalic anhydride Chemical compound C1CCCC2C(=O)OC(=O)C21C VYKXQOYUCMREIS-UHFFFAOYSA-N 0.000 description 15
- 239000000463 material Substances 0.000 description 12
- 239000004841 bisphenol A epoxy resin Substances 0.000 description 10
- 239000000306 component Substances 0.000 description 7
- 230000008569 process Effects 0.000 description 6
- 230000001105 regulatory effect Effects 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- FAUAZXVRLVIARB-UHFFFAOYSA-N 4-[[4-[bis(oxiran-2-ylmethyl)amino]phenyl]methyl]-n,n-bis(oxiran-2-ylmethyl)aniline Chemical compound C1OC1CN(C=1C=CC(CC=2C=CC(=CC=2)N(CC2OC2)CC2OC2)=CC=1)CC1CO1 FAUAZXVRLVIARB-UHFFFAOYSA-N 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 230000009477 glass transition Effects 0.000 description 4
- 239000004842 bisphenol F epoxy resin Substances 0.000 description 3
- 230000015556 catabolic process Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002105 nanoparticle Substances 0.000 description 3
- 238000003756 stirring Methods 0.000 description 3
- AHDSRXYHVZECER-UHFFFAOYSA-N 2,4,6-tris[(dimethylamino)methyl]phenol Chemical compound CN(C)CC1=CC(CN(C)C)=C(O)C(CN(C)C)=C1 AHDSRXYHVZECER-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000003949 trap density measurement Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- 229930185605 Bisphenol Natural products 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 150000008065 acid anhydrides Chemical group 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
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- 238000004132 cross linking Methods 0.000 description 1
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- 238000000113 differential scanning calorimetry Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- 238000009472 formulation Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 150000002460 imidazoles Chemical class 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000006082 mold release agent Substances 0.000 description 1
- 239000002114 nanocomposite Substances 0.000 description 1
- 150000007524 organic acids Chemical class 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 238000010125 resin casting Methods 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- KKEYFWRCBNTPAC-UHFFFAOYSA-L terephthalate(2-) Chemical compound [O-]C(=O)C1=CC=C(C([O-])=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-L 0.000 description 1
- 150000003751 zinc Chemical class 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B19/00—Apparatus or processes specially adapted for manufacturing insulators or insulating bodies
- H01B19/02—Drying; Impregnating
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/40—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the curing agents used
- C08G59/42—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof
- C08G59/4215—Polycarboxylic acids; Anhydrides, halides or low molecular weight esters thereof cycloaliphatic
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G59/00—Polycondensates containing more than one epoxy group per molecule; Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups
- C08G59/18—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing
- C08G59/68—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the catalysts used
- C08G59/686—Macromolecules obtained by polymerising compounds containing more than one epoxy group per molecule using curing agents or catalysts which react with the epoxy groups ; e.g. general methods of curing characterised by the catalysts used containing nitrogen
-
- C—CHEMISTRY; METALLURGY
- 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
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/20—Applications use in electrical or conductive gadgets
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
- C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
The invention relates to a low-temperature conductive activation energy epoxy resin composition, a preparation method and application thereof, wherein the epoxy resin composition comprises the following components in parts by weight: 100 parts of epoxy resin blend, 85-110 parts of curing agent and 0.01-1 part of accelerator; the epoxy resin blend uses difunctional epoxy resin as a matrix and high functionality epoxy resin as a modifier. The epoxy resin composition with low temperature conductivity activation energy is applied to casting and dipping of the high-voltage direct current dry sleeve insulator core, and the electric field distribution inside the insulator core under the condition of large temperature gradient is improved through reduced conductivity temperature dependence. The cured epoxy resin composition prepared by the invention has excellent electrical insulation, mechanical and heat resistance, and particularly, the low-temperature conductivity activation energy of the cured product can improve the electric field distribution in the high-voltage direct current sleeve insulating core under the temperature gradient distribution, so that the cured epoxy resin composition can be widely applied to high-voltage or ultra-high voltage direct current sleeves.
Description
Technical Field
The invention belongs to the technical field of high-voltage equipment, and relates to a high-voltage direct-current sleeve, in particular to an epoxy resin composition with low-temperature conductivity activation energy, a preparation method and application.
Background
The high-voltage direct current dry sleeve is core equipment in an ultra-high voltage converter station, plays a role in insulation and isolation and mechanical support, and the performance of the high-voltage direct current dry sleeve directly influences the safe and stable operation of a high-voltage transmission project. In order to respond to the requirement of 'valve hall oilless' of high-voltage direct current engineering in China, the high-voltage direct current bushings in the converter stations all adopt dry structures, wherein an epoxy impregnated paper (Resin-impregnated paper, RIP) insulating core body is a bushing core component. Epoxy resin is a key basic material of an RIP insulating core body, in the process of processing the sleeve core body, crepe paper or fiber cloth (containing a voltage-equalizing shielding layer) is wound on a current-carrying conductor, then the sleeve insulating core body is prepared by casting and impregnating the sleeve core body with the epoxy resin in a vacuum environment, curing and forming the sleeve core body under the condition of temperature gradient, and finally turning the sleeve core body.
At present, the high-voltage direct current bushing still adopts the design structure of the alternating current bushing, and the insulation in the bushing adopts a capacitor core structure with aluminum foil shielding to perform electric field homogenization, however, the electric field distribution and influencing factors of the direct current bushing and the alternating current bushing are different. The electric field distribution inside the ac bushing is determined by the dielectric constant of the insulating material, which changes less with temperature, and the electric field distribution inside the bushing is relatively fixed when the operating voltage is determined. Unlike ac bushings, the distribution of the electric field in the insulation under dc conditions depends on the medium dc conductivity, which is significantly affected by temperature. Because of the high bearing voltage, the bushing insulation thickness is large, and the epoxy insulation is a 'hot bad conductor', so that the bushing insulation core forms a significant temperature gradient from inside to outside under a high load current. The insulation conductivity is affected by temperature and is in strong nonlinear distribution, so that the electric field distribution in the bushing insulation is deviated, and the field intensity at key parts is concentrated. Meanwhile, the high-voltage direct-current sleeve has a complex running environment, and the change of external factors such as valve hall temperature, current carrying capacity, transformer oil temperature and the like can lead to the change of the temperature inside the sleeve, so that the electric field distribution is influenced, and the effect of a single insulating structure optimization method is limited when the electric field distribution inside the direct-current sleeve is regulated and controlled. Thus, the "shape control" is also required in the design of the sleeve. The method for regulating the direct current conductivity of the epoxy resin material for the high-voltage direct current sleeve mainly comprises the steps of adding inorganic nano particles, so that the temperature activation energy of the insulating conductivity of the composite material can be reduced due to the interface region effect and the intrinsic low-temperature conductivity of the nano particles, but the key problems of high formula viscosity, easy agglomeration of the nano particles, reduced insulating property and the like exist in the application of the nano composite material to the high-voltage direct current sleeve, and the application of the technical route is still in a theoretical exploration stage.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an epoxy resin composition with low temperature conductivity activation energy, a preparation method and application thereof, and the epoxy resin composition can reduce the problem of high conductivity temperature activation energy of an epoxy resin formula system for a traditional high-voltage dry bushing by utilizing the characteristics of high intrinsic conductivity of a high-functional epoxy resin network modifier and increased trap density of a cured product, and realize the optimized regulation function of electric field distribution in the insulation of a high-voltage direct current bushing under a large temperature gradient.
The invention solves the technical problems in the prior art by adopting the following technical scheme:
the epoxy resin composition with low temperature conductivity and activation energy comprises the following components in parts by weight: 100 parts of epoxy resin blend, 85-110 parts of curing agent and 0.01-1 part of accelerator; the epoxy resin blend takes difunctional epoxy resin as a matrix and high-functionality epoxy resin as a modifier.
Further, the difunctional epoxy resin is aromatic or alicyclic epoxy resin, and the molecular chain of the difunctional epoxy resin contains two epoxy groups, and the weight part of the difunctional epoxy resin is 85-97 parts; the molecular chain of the Gao Guanneng epoxy resin contains more than two epoxy groups, and the weight part is 3-15.
Further, the difunctional epoxy resin is one or a combination of at least two of bisphenol a epoxy resin, bisphenol F epoxy resin, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexylformate, 1, 6-bis (2, 3-epoxypropoxy) naphthalene; the Gao Guanneng epoxy resin is one or a combination of at least two of triglycidyl meta-aminophenol, triglycidyl para-aminophenol and 4, 4-diaminodiphenylmethane tetraglycidyl amine.
Further, the epoxy resin blend has a room temperature viscosity of less than 10000 mPa.s and an epoxy value of 4 to 6.5eq/kg.
Further, the epoxy resin blend has a room temperature viscosity in the range of 4000-6000 mPas and an epoxy value in the range of 5.6-6.2eq/kg.
Further, the curing agent is an anhydride curing agent, and the anhydride curing agent is one or a combination of at least two of hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methyl nadic anhydride.
Further, the accelerator is one or a combination of at least two of tertiary amine accelerator, imidazole, boron acyl halide amine complex and organic acid zinc salt.
A method for preparing an epoxy resin composition with low temperature conductivity and activation energy, comprising the following steps: mixing difunctional epoxy resin and high-functionality epoxy resin in proportion to obtain an epoxy resin blend; mixing the epoxy resin blend, the curing agent and the accelerator in proportion; vacuum degassing is carried out after mechanical stirring, so that no obvious bubbles are generated in the cured resin; pouring into a mould, and curing under the condition of gradient temperature; finally, demolding is carried out to obtain the cured epoxy resin composition.
Further, the temperature range of the gradient temperature condition is 60-180 ℃, and continuous heating curing or multistage gradient curing is adopted.
The application of the epoxy resin composition with low temperature conductivity activation energy is that the epoxy resin composition with low temperature conductivity activation energy is applied to casting and dipping of a high-voltage direct current dry sleeve insulation core, and the electric field distribution inside the insulation core under the condition of large temperature gradient is improved through reduced conductivity temperature dependence.
The invention has the advantages and positive effects that:
1. the epoxy resin composition with low temperature conductivity activation energy is prepared by optimizing the types and the proportions of the epoxy resin blend, the curing agent and the accelerator, and can meet the processing technology and the performance requirements of the high-voltage direct current dry sleeve. Particularly, the network structure of the epoxy resin cured product is regulated and controlled by the high-functional epoxy resin modifier, so that the microscopic crosslinking density of the cured product is increased, the trap density is increased, and further, the improvement of the glass transition temperature and the improvement of the dielectric property at high temperature are obtained; meanwhile, the energy gap of the intrinsic material of the high-functional epoxy resin is lower than that of the difunctional epoxy resin, and more unreacted epoxy groups are introduced into the high-functional epoxy resin, so that the carrier concentration of the intrinsic material at low temperature is increased. Therefore, compared with the traditional bisphenol A-anhydride resin casting system, the epoxy resin condensate provided by the invention has higher low-temperature conductivity and lower high-temperature conductivity, namely the temperature dependence and the temperature activation energy of the direct-current conductivity of the material are reduced, and the epoxy resin condensate has important significance for improving the electric field distribution in the direct-current sleeve under a large temperature gradient.
2. The cured epoxy resin composition prepared by the invention has excellent electrical insulation, mechanical and heat resistance, particularly, the low-temperature conductivity activation energy, namely the dependence of conductivity on temperature under direct current condition is reduced, the electric field distribution in the high-voltage direct current sleeve insulation core under temperature gradient distribution can be improved, and the cured epoxy resin composition can be widely applied to high-voltage or ultra-high voltage direct current sleeves.
Drawings
FIG. 1 is a process flow of the epoxy resin cured product preparation process of the present invention;
FIG. 2 is a graph showing a temperature conductance fit of the epoxy resin cured product prepared according to the present invention.
Detailed Description
Embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
The design idea of the invention is as follows: the epoxy resin performance regulating and controlling method based on the network modifier is adopted, and the insulation, heat resistance and mechanical properties of the epoxy resin system can be cooperatively improved through formula optimization. By introducing the epoxy modifier with high functionality into the traditional bisphenol A type epoxy resin-anhydride formula system, the internal microstructure and trap level distribution of the cured product are regulated and controlled, the temperature dependence of the direct current conduction of epoxy insulation can be effectively reduced, and the internal electric field distribution of the direct current bushing insulation under a large temperature gradient is regulated and controlled.
Based on the design concept, the invention provides a low-temperature conductive activation energy epoxy resin composition which consists of, by weight, 100 parts of an epoxy resin blend, 85-110 parts of a curing agent and 0.01-1 part of an accelerator, wherein the epoxy resin blend comprises 85-97 parts of a difunctional epoxy resin serving as a matrix and 3-15 parts of a high-functionality epoxy resin serving as a modifier. The cured product of the epoxy resin composition has excellent electrical insulation, mechanical and heat resistance, and in particular, the cured product has low-temperature conductivity activation energy, namely, the dependence of the conductivity on temperature under direct current conditions is low. The specific components are shown in the following table:
in the present invention, the difunctional epoxy resin in the epoxy resin blend may be an aromatic or alicyclic epoxy resin having two epoxy groups in the molecular chain thereof in an amount of 85 to 97 parts by weight, for example, 85 parts, 90 parts, 95 parts or 97 parts, etc. may be selected.
The difunctional epoxy resin may be selected from any one or a combination of the following materials: bisphenol a epoxy resin, bisphenol F epoxy resin, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexylformate, 1, 6-bis (2, 3-epoxypropoxy) naphthalene, or a combination of at least two thereof. For example, bisphenol a type epoxy resin, a blend of bisphenol a and bisphenol F resin, or the like may be used.
In the invention, the molecular chain of the high-functional epoxy resin in the epoxy resin blend contains more than two epoxy groups, the weight parts are 3-15 parts, and the sum of the parts is 100 parts after the high-functional epoxy resin and the difunctional epoxy resin are blended. For example, when 85 parts of the difunctional epoxy resin is selected, 15 parts of the high functional epoxy resin modifier should be used; when 95 parts of the difunctional epoxy resin is selected, the high-functional epoxy resin modifier should be 5 parts.
The Gao Guanneng epoxy resin can be any one or a combination of the following materials: triglycidyl meta-aminophenol, triglycidyl para-aminophenol, 4-diaminodiphenylmethane tetraglycidyl amine. For example, triglycidyl meta-aminophenol alone or a blend of triglycidyl meta-aminophenol and 4, 4-diaminodiphenylmethane tetraglycidyl amine may be used as the modifier.
In the invention, in order to meet the high-voltage direct-current sleeve casting and dipping process, the room temperature viscosity of the epoxy resin blend is less than 10000 mPa.s, and the epoxy value is 4-6.5eq/kg. As a preferred embodiment, the epoxy resin blend has a room temperature viscosity of 4000-6000 mPas and an epoxy value of 5.6-6.2eq/kg.
In the present invention, the curing agent is an acid anhydride-based curing agent. The anhydride curing agent can be any one or a combination of the following materials: hexahydrophthalic anhydride (HHPA), methyl hexahydrophthalic anhydride (MHHPA), methyl tetrahydrophthalic anhydride (MTHPA) and Methyl Nadic Anhydride (MNA). The curing agent is used in an amount of 85-110 parts by weight, for example, 90 parts of MHHPA may be used as the curing agent, or a blend of 95 parts of MHHPA and HHPA may be used as the curing agent.
In the present invention, the accelerator may be selected from any one or a combination of the following materials: tertiary amine accelerators, imidazoles, boron acyl halide amine complexes and zinc salts of organic acids. The weight portion of the accelerator is between 0.01 and 1 part, for example, the accelerator can be 0.05 part, 0.1 part, 0.5 part, 1 part and the like. As a preferred embodiment, the accelerators include 2,4, 6-tris (dimethylaminomethyl) phenol (DMP-30) and Benzyl Dimethylamine (BDMA).
Based on the epoxy resin composition with low temperature conductivity and activation energy, the invention also provides a preparation method of the epoxy resin composition with low temperature conductivity and activation energy, as shown in figure 1, comprising the following steps:
step 1, mixing difunctional epoxy resin and high-functionality epoxy resin in proportion to obtain an epoxy resin blend;
step 2, mixing the epoxy resin blend, the curing agent and the accelerator in proportion to obtain an epoxy resin composition;
step 3, mechanically stirring the epoxy resin composition obtained in the step 2, and carrying out degassing treatment in a vacuum environment, wherein the degassing time can be adjusted according to the weight of the composition, so that no obvious bubbles are generated in the cured resin;
and 4, pouring the epoxy resin composition obtained in the step 3 into a preheated mold, and curing under the gradient temperature condition.
In the step, the temperature range of the gradient temperature condition is 60-180 ℃, the continuous heating curing can be adopted, the multistage gradient curing can be adopted, for example, the linear heating from 80 degrees to 160 degrees can be adopted for 24 hours of curing, and the combined curing system of 100 degrees for 12 hours and 140 degrees for 24 hours can be adopted
And 5, naturally cooling the solidified grinding tool to room temperature, and performing demolding treatment to obtain a solidified epoxy resin composition finished product.
The cured epoxy resin composition with low temperature conductivity activation energy can be prepared through the steps, the direct current conductivity activation energy of the cured epoxy resin composition is less than 0.85eV, the glass transition temperature is 110-135 ℃, the power frequency dielectric constant is less than 3.5, the breakdown strength is more than 30kV/mm, and the tensile strength is 60-80MPa.
Based on the epoxy resin composition with low temperature conductivity activation energy, the invention also provides application of the epoxy resin composition with low temperature conductivity activation energy, the epoxy resin composition with low temperature conductivity activation energy is applied to casting and dipping of a high-voltage direct current dry type sleeve insulation core, and the reduced conductivity temperature dependence can improve the electric field distribution inside the insulation core under the condition of large temperature gradient.
To verify the effect of the present invention, the applicant carried out performance tests using the following examples and comparative examples:
example 1:
the epoxy resin composition with low temperature conductivity and activation energy of the embodiment comprises the following components: comprises 93 parts of bisphenol A epoxy resin (epoxy value 5.0-5.6 eq/kg), 7 parts of tetrafunctional epoxy resin 4, 4-diaminodiphenyl methane tetraglycidyl amine (TGDDM), 90 parts of methyl hexahydrophthalic anhydride (MHHPA) and 0.1 part of accelerator Benzyl Dimethylamine (BDMA) in parts by weight.
In this example, a cured epoxy resin composition was prepared using the following method:
firstly, weighing bisphenol A epoxy resin and TGDDM (polyethylene glycol terephthalate) in corresponding parts by weight by using an electronic balance, heating in a 60-DEG water bath, and mechanically stirring for 30 minutes to ensure that the TGDDM can be uniformly mixed with the bisphenol A to obtain an epoxy resin blend 1;
then, weighing the corresponding parts by weight of the MHHPA curing agent and BDMA accelerator and compounding the mixture 1, heating in a water bath at 60 ℃ and mechanically stirring for 1 hour to ensure that the epoxy resin, the curing agent and the accelerator can be uniformly mixed to obtain an epoxy resin composition 1;
then, the composition was subjected to vacuum degassing treatment under 80 ℃ for 1 hour to sufficiently remove bubbles possibly contained in the formulation; meanwhile, the epoxy resin mold was pre-heat treated for 1 hour in an environment of 100 degrees, in which the mold had been treated with a mold release agent.
Then, the epoxy resin composition was poured into a preheated mold under vacuum, put into an oven for curing, cured for 15 hours under 100 degrees by using a two-stage curing process, and then cured for 20 hours by increasing the temperature to 140 degrees.
Finally, after the mold is naturally cooled to room temperature, demolding is carried out, and a solidified epoxy resin product is obtained.
Example 2:
the epoxy resin composition with low temperature conductivity and activation energy of the embodiment comprises the following components: 90 parts of bisphenol A epoxy resin (epoxy value 5.0-5.6 eq/kg), 10 parts of triglycidyl meta-aminophenol (TGAP), 90 parts of methyl hexahydrophthalic anhydride (MHHPA) and 0.1 part of accelerator Benzyl Dimethylamine (BDMA).
The procedure of the cured epoxy resin composition prepared in this example was the same as in example 1.
Example 3:
the epoxy resin composition with low temperature conductivity and activation energy of the embodiment comprises the following components: comprises 70 parts of bisphenol A epoxy resin (epoxy value 5.0-5.6 eq/kg), 20 parts of bisphenol F epoxy resin (epoxy value 5.4-5.8 eq/kg), 10 parts of triglycidyl meta-aminophenol (TGAP), 90 parts of methyl hexahydrophthalic anhydride (MHHPA) and 0.1 part of promoter Benzyl Dimethylamine (BDMA) in parts by weight.
The procedure of the cured epoxy resin composition prepared in this example was the same as in example 1.
Example 4:
the epoxy resin composition with low temperature conductivity and activation energy of the embodiment comprises the following components: 90 parts of bisphenol A epoxy resin (epoxy value 5.0-5.6 eq/kg), 5 parts of tetrafunctional epoxy resin 4, 4-diaminodiphenylmethane tetraglycidyl amine (TGDDM), 5 parts of triglycidyl meta-aminophenol (TGAP), 90 parts of methyl hexahydrophthalic anhydride (MHHPA) and 0.1 part of accelerator Benzyl Dimethylamine (BDMA).
The procedure of the cured epoxy resin composition prepared in this example was the same as in example 1.
Example 5:
the epoxy resin composition with low temperature conductivity and activation energy of the embodiment comprises the following components: 90 parts of bisphenol A epoxy resin (epoxy value 5.0-5.6 eq/kg), 10 parts of tetrafunctional epoxy resin 4, 4-diaminodiphenyl methane tetraglycidyl amine (TGDDM), 85 parts of methyltetrahydrophthalic anhydride (MTHPA) and 0.1 part of accelerator Benzyl Dimethylamine (BDMA) in parts by weight.
The process for curing the epoxy resin composition prepared in this example was similar to that of example 1, except that the curing system was changed, the epoxy resin mold was pre-heat treated for 1 hour in an 80 degree environment, and cured for 12 hours in an 80 degree environment using a two-stage curing process, and then the temperature was raised to 130 degrees for 24 hours.
Comparative example 1:
a traditional casting formula system of a high-pressure dry sleeve comprises 100 parts by weight of bisphenol A epoxy resin (with an epoxy value of 5.4-5.6 eq/kg), 90 parts by weight of methyl hexahydrophthalic anhydride (MHHPA) and 0.2 part by weight of promoter Benzyl Dimethylamine (BDMA). The cured product of comparative example 1 was prepared by a conventional method.
Comparative example 2:
a traditional casting formula system of a high-pressure dry sleeve comprises 100 parts by weight of bisphenol A epoxy resin (with an epoxy value of 5.4-5.6 eq/kg), 85 parts by weight of methyltetrahydrophthalic anhydride (MTHPA) and 0.2 part by weight of promoter Benzyl Dimethylamine (BDMA). The cured product of comparative example 2 was prepared by a conventional method.
After the test, the direct current conductivity test and the activation energy calculation are respectively carried out:
the direct current conductivity of the condensate at different temperatures is measured by adopting a three-electrode method, the temperature dependence of the conductance is linearly fitted by adopting an Arrhenius public expression, and the temperature activation energy of the conductance is obtained by calculation, wherein the calculation public expression is as follows:
wherein, gamma is conductivity (S/m), gamma 0 Is a constant (S/m) related to the material properties, E a Is the conductivity activation energy (eV) of the material, q is the charge quantity of the charge unit (1.6X10) -19 )，k b Is Boltzmann constant 1.38X10 -23 (J/K), T is the temperature (K).
Breakdown strength: testing in transformer oil by adopting a ball-ball electrode, and executing according to national standard GB/T1408.1;
tensile strength: the test is carried out by adopting a universal electronic tensile machine and referring to national standard GB/T2567.
Glass transition temperature: measured using differential scanning calorimetry.
Power frequency dielectric constant: obtained by measurement with a broadband dielectric spectrometer and executed by referring to national standard GB/T1410.
The performance indexes obtained by the above test are shown in fig. 2 and the following table:
as can be seen from the comparison test, the epoxy resin composition formula and the epoxy cured product obtained by the preparation process have excellent insulation, heat resistance and mechanical properties, the direct current conduction temperature activation energy is less than 0.85eV, the glass transition temperature is 110-135 ℃, the power frequency dielectric constant is less than 3.5, the breakdown strength is more than 30kV/mm, and the tensile strength is 60-80MPa, so that the application requirements of high-voltage direct current dry-type bushings in different voltage classes and occasions are met.
It should be emphasized that the examples described herein are illustrative rather than limiting, and therefore the invention includes, but is not limited to, the examples described in the detailed description, all other embodiments that may be derived by a person skilled in the art from the technical solutions of the invention are equally within the scope of the invention.
Claims (10)
1. An epoxy resin composition with low temperature conductivity activation energy, which is characterized in that: the components of the composition are as follows in parts by weight: 100 parts of epoxy resin blend, 85-110 parts of curing agent and 0.01-1 part of accelerator; the epoxy resin blend takes difunctional epoxy resin as a matrix and high-functionality epoxy resin as a modifier.
2. The low temperature, electrically conductive, activatable epoxy resin composition of claim 1, wherein: the difunctional epoxy resin is aromatic or alicyclic epoxy resin, and the molecular chain of the difunctional epoxy resin contains two epoxy groups, wherein the weight part of the difunctional epoxy resin is 85-97 parts; the molecular chain of the Gao Guanneng epoxy resin contains more than two epoxy groups, and the weight part is 3-15.
3. The low temperature, electrically conductive, activatable epoxy resin composition of claim 2, wherein: the difunctional epoxy resin is one or a combination of at least two of bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexylformate and 1, 6-bis (2, 3-epoxypropoxy) naphthalene; the Gao Guanneng epoxy resin is one or a combination of at least two of triglycidyl meta-aminophenol, triglycidyl para-aminophenol and 4, 4-diaminodiphenylmethane tetraglycidyl amine.
4. The low temperature, electrically conductive, activatable epoxy resin composition of claim 1, wherein: the epoxy resin blend has a room temperature viscosity of less than 10000 mPa.s and an epoxy value of 4-6.5eq/kg.
5. The low temperature, electrically conductive, activatable epoxy resin composition of claim 4, wherein: the epoxy resin blend has a room temperature viscosity in the range of 4000-6000 mPas and an epoxy value in the range of 5.6-6.2eq/kg.
6. The low temperature, electrically conductive, activatable epoxy resin composition of claim 1, wherein: the curing agent is an anhydride curing agent, and the anhydride curing agent is one or a combination of at least two of hexahydrophthalic anhydride, methyl tetrahydrophthalic anhydride and methyl nadic anhydride.
7. The low temperature, electrically conductive, activatable epoxy resin composition of claim 1, wherein: the accelerator is one or the combination of at least two of tertiary amine accelerator, imidazole, boron acyl halide amine complex and organic acid zinc salt.
8. A process for preparing a low temperature conductive activation energy epoxy resin composition as claimed in any one of claims 1 to 7, wherein: the method comprises the following steps: mixing difunctional epoxy resin and high-functionality epoxy resin in proportion to obtain an epoxy resin blend; mixing the epoxy resin blend, the curing agent and the accelerator in proportion; vacuum degassing is carried out after mechanical stirring, so that no obvious bubbles are generated in the cured resin; pouring into a mould, and curing under the condition of gradient temperature; finally, demolding is carried out to obtain the cured epoxy resin composition.
9. The method for preparing a low temperature conductive activation energy epoxy resin composition according to claim 8, wherein: the temperature range of the gradient temperature condition is 60-180 ℃, and continuous heating curing or multistage gradient curing is adopted.
10. Use of the low temperature conductive activation energy epoxy resin composition of any one of claims 1-7, characterized in that: the epoxy resin composition with low temperature conductivity activation energy is applied to casting and dipping of the high-voltage direct current dry sleeve insulator core, and the electric field distribution inside the insulator core under the condition of large temperature gradient is improved through reduced conductivity temperature dependence.
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