Epoxy resin composition with low-temperature conductivity activation energy, preparation method and application

Abstract

The present invention relates to an epoxy resin composition with a low temperature conductivity activation energy, a preparation method and an application thereof. The constituent components of the epoxy resin composition and the weight parts of the components are as follows: 100 parts of an epoxy resin blend, 85 - 110 parts of a curing agent, and 0.01 - 1 part of an accelerator; the epoxy resin blend uses a bifunctional epoxy resin as a matrix and a high-functional epoxy resin as a modifier. The epoxy resin composition with a low temperature conductivity activation energy is applied to the casting and impregnation of the insulation core of a high-voltage DC dry bushing, and the internal electric field distribution of the insulation core under large temperature gradient conditions is improved by reducing the temperature dependence of conductivity. The cured epoxy resin composition prepared by the present invention has excellent electrical insulation, mechanical and heat resistance properties. In particular, the cured product has a low temperature conductivity activation energy, which can improve the internal electric field distribution of the insulation core of a high-voltage DC bushing under a temperature gradient distribution, and thus can be widely applied in high-voltage or extra-high-voltage DC bushings.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage equipment, relates to high-voltage DC bushings, and in particular to an epoxy resin composition with low temperature conductivity activation energy, a preparation method and an application thereof. Background Art

[0002] High-voltage DC dry bushings are core equipment in ultra-high voltage converter stations, playing roles of insulation isolation and mechanical support, and their performance directly affects the safe and stable operation of high-voltage power transmission projects. To meet the requirement of "oil-free in valve halls" for high-voltage DC projects in China, all high-voltage DC bushings in converter stations adopt dry structures, and among them, the epoxy resin-impregnated paper (RIP) insulation core is the core component of the bushing. Epoxy resin is a key basic material for the RIP insulation core. During the processing of the bushing core, first, crimped paper or fiber cloth (containing grading shielding layers) is wound around the current-carrying conductor, and then it is cast and impregnated with epoxy resin in a vacuum environment, cured and formed under temperature gradient conditions, and finally processed by turning to make the bushing insulation core.

[0003] Currently, the design structure of high-voltage DC bushings still follows that of AC bushings. The internal insulation of the bushing uses a capacitor core structure with aluminum foil shielding for electric field homogenization. However, the electric field distributions and influencing factors of DC bushings and AC bushings are different. The electric field distribution inside an AC bushing is determined by the relative permittivity of the insulating material, and the relative permittivity changes little with temperature. When the operating voltage is determined, the electric field distribution inside the bushing is relatively fixed. Different from AC bushings, under DC conditions, the internal electric field distribution of the insulation depends on the DC conductivity of the medium, which is significantly affected by temperature. Due to the high load voltage and large insulation thickness of the bushing, and the epoxy resin insulation being a "poor conductor of heat", a significant temperature gradient is formed from the inside to the outside of the bushing insulation core under large load currents. The insulation conductivity shows a strong non-linear distribution with temperature, resulting in the offset of the internal electric field distribution of the bushing and field strength concentration at key positions. At the same time, the operating environment of high-voltage DC bushings is complex, and changes in external factors such as the valve hall temperature, current-carrying capacity, and transformer oil temperature will all cause changes in the internal temperature of the bushing, thereby affecting the electric field distribution, making the effect of a single insulation structure optimization method limited in regulating the internal electric field distribution of DC bushings. Therefore, in the design of bushings, it is necessary to "control the shape" while also "controlling the properties". The method for regulating the DC conductivity characteristics of epoxy resin materials for high-voltage DC bushings mainly involves adding inorganic nanoparticles. Due to the interfacial region effect and intrinsic low-temperature conductivity characteristics of the nanoparticles, the temperature activation energy of the composite material insulation conductivity can be reduced to a certain extent. However, there are key problems such as high formulation viscosity, easy agglomeration of nanoparticles, and degradation of insulation performance when applying nanocomposites to high-voltage DC bushings, making the application of this technical route still in the theoretical exploration stage. Summary of the Invention

[0004] The object of the present invention is to overcome the deficiencies of the prior art and provide an epoxy resin composition, a preparation method and an application thereof with a low temperature conductivity activation energy. By utilizing the characteristics of high intrinsic conductivity of the high-functional epoxy resin network modifier and the increase in the trap density of the cured product, the problem of high conductivity temperature activation energy of the traditional epoxy resin formulation system for high-voltage dry bushings is reduced, and the optimized regulation function of the internal electric field distribution of the insulation of high-voltage DC bushings under a large temperature gradient is realized.

[0005] The technical problems existing in the present invention are solved by adopting the following technical solutions:

[0006] An epoxy resin composition with a low temperature conductivity activation energy, the components thereof and the weight parts of the components are as follows: 100 parts of an epoxy resin blend, 85 - 110 parts of a curing agent, and 0.01 - 1 part of an accelerator; the epoxy resin blend uses a bifunctional epoxy resin as the matrix and a high-functional epoxy resin as the modifier.

[0007] Further, the bifunctional epoxy resin is an aromatic or alicyclic epoxy resin, which contains two epoxy groups in its molecular chain, and the weight part is 85 - 97 parts; the high-functional epoxy resin contains more than two epoxy groups in its molecular chain, and the weight part is 3 - 15 parts.

[0008] Further, the bifunctional epoxy resin is one or at least two combinations of bisphenol A epoxy resin, bisphenol F epoxy resin, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1,6-bis(2,3-epoxypropoxy)naphthalene; the high-functional epoxy resin is one or at least two combinations of triglycidyl m-aminophenol, triglycidyl p-aminophenol, and tetraglycidyl-4,4'-diaminodiphenylmethane.

[0009] Further, the room temperature viscosity of the epoxy resin blend is less than 10000 mPa·s, and the epoxy value is 4 - 6.5 eq / kg.

[0010] Further, the room temperature viscosity range of the epoxy resin blend is 4000 - 6000 mPa·s, and the epoxy value range is 5.6 - 6.2 eq / kg.

[0011] Further, the curing agent is an acid anhydride curing agent, and the acid anhydride curing agent is one or at least two combinations of hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride.

[0012] Further, the accelerator is one or at least two combinations of a tertiary amine accelerator, imidazole, a boron halide amine complex, and an organic acid zinc salt.

[0013] A preparation method of an epoxy resin composition with low temperature conductivity activation energy, comprising the following steps: blending a bifunctional epoxy resin and a high-functional epoxy resin in proportion to obtain an epoxy resin blend; blending the epoxy resin blend, a curing agent and an accelerator in proportion; performing mechanical stirring and then vacuum degassing to ensure that there are no obvious bubbles inside the resin after curing; then pouring it into a mold and curing it under gradient temperature conditions; finally demolding to obtain a cured epoxy resin composition.

[0014] Further, the temperature range of the gradient temperature conditions is 60-180°C, and continuous heating curing or multi-stage gradient curing is adopted.

[0015] An application of an epoxy resin composition with low temperature conductivity activation energy, applying the epoxy resin composition with low temperature conductivity activation energy to the casting and impregnation of the insulation core of a high-voltage DC dry bushing, and improving the internal electric field distribution of the insulation core under large temperature gradient conditions by reducing the temperature dependence of conductivity.

[0016] The advantages and positive effects of the present invention are:

[0017] 1. The present invention prepares an epoxy resin composition with low temperature conductivity activation energy by optimizing the types and ratios of the epoxy resin blend, curing agent and accelerator, which can meet the processing technology and performance requirements of high-voltage DC dry bushings. In particular, by regulating the network structure of the epoxy resin cured product using a high-functional epoxy resin modifier, the crosslinking density and trap density of the cured product increase microscopically, thereby obtaining an increase in the glass transition temperature and an improvement in the dielectric properties at high temperatures; at the same time, the intrinsic material bandgap width of the high-functional epoxy resin is lower than that of the bifunctional epoxy resin, and the more unreacted epoxy groups introduced by it increase the carrier concentration of the intrinsic material at low temperatures. Therefore, compared with the traditional bisphenol A-anhydride resin casting system, the epoxy resin cured product of the present invention has a higher low-temperature conductivity and a lower high-temperature conductivity, that is, the temperature dependence and temperature activation energy of the direct current conductivity of the material are reduced, which is of great significance for improving the internal electric field distribution of DC bushings under large temperature gradients.

[0018] 2. The cured epoxy resin composition prepared by the present invention has excellent electrical insulation, mechanical and heat resistance properties. In particular, the low temperature conductivity activation energy, that is, the temperature dependence of conductivity under direct current conditions is reduced, which can improve the internal electric field distribution of the insulation core of high-voltage DC bushings under temperature gradient distribution, and thus can be widely applied in high-voltage or extra-high-voltage DC bushings. Description of the Drawings

[0019] Figure 1 is the preparation process flow of the epoxy resin cured product of the present invention;

[0020] Figure 2It is the temperature-conductance fitting curve of the cured epoxy resin prepared by the present invention. Detailed Embodiments

[0021] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0022] The design concept of the present invention is: adopting a method for regulating the properties of epoxy resin based on network modifiers, and through formula optimization, the insulation, heat resistance and mechanical properties of the epoxy resin system can be synergistically improved. By introducing highly functional epoxy modifiers into the traditional bisphenol A type epoxy resin-anhydride formula system, the internal microstructure and trap energy level distribution of the cured product can be regulated, which can effectively reduce the temperature dependence of the DC conductance of epoxy insulation, and then regulate the internal electric field distribution of DC bushing insulation under a large temperature gradient.

[0023] Based on the above design concept, the present invention proposes an epoxy resin composition with a low temperature-conductance activation energy. The epoxy resin composition is composed of 100 parts by weight of an epoxy resin blend, 85-110 parts by weight of a curing agent, and 0.01-1 part by weight of an accelerator. Among them, the epoxy resin blend includes 85-97 parts by weight of a bifunctional epoxy resin as the matrix and 3-15 parts by weight of a highly functional epoxy resin as the modifier. The cured product of the epoxy resin composition has excellent electrical insulation, mechanical and heat resistance properties. In particular, the cured product has a low temperature-conductance activation energy, that is, its conductance has a low temperature dependence under DC conditions. Its specific components are shown in the following table:

[0024]

[0025] In the present invention, the bifunctional epoxy resin in the epoxy resin blend can be an aromatic or alicyclic epoxy resin, which contains two epoxy groups in its molecular chain and the weight fraction is between 85 and 97, such as 85 parts, 90 parts, 95 parts or 97 parts, etc.

[0026] Any one of the following materials or a combination thereof can be selected as the above bifunctional epoxy resin: bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 1,6-bis(2,3-epoxypropoxy)naphthalene, or a combination of at least two of them. For example, bisphenol A type epoxy resin can be used, or a blend of bisphenol A and bisphenol F resins can also be used, etc.

[0027] In the present invention, the highly functional epoxy resin in the epoxy resin blend contains more than two epoxy groups in its molecular chain, and the weight fraction is 3-15 parts. After blending with the bifunctional epoxy resin, the sum of their parts is 100 parts. For example, when the bifunctional epoxy resin is selected as 85 parts, the highly functional epoxy resin modifier should be 15 parts; when the bifunctional epoxy resin is selected as 95 parts, the highly functional epoxy resin modifier should be 5 parts.

[0028] The above high-functional epoxy resin can be selected from any one of the following materials or their combinations: triglycidyl m-aminophenol, triglycidyl p-aminophenol, 4,4-diaminodiphenylmethane tetraglycidylamine. For example, triglycidyl m-aminophenol can be used alone as a modifier, or a blend of triglycidyl m-aminophenol and 4,4-diaminodiphenylmethane tetraglycidylamine can be used as a modifier.

[0029] In the present invention, to meet the casting and impregnation process of high-voltage DC bushings, the room temperature viscosity of the epoxy resin blend should be less than 10,000 mPa·s, and the epoxy value should be 4 - 6.5 eq / kg. As a preferred embodiment, the room temperature viscosity of the epoxy resin blend is 4,000 - 6,000 mPa·s, and the epoxy value is 5.6 - 6.2 eq / kg.

[0030] In the present invention, the curing agent is an acid anhydride curing agent. The acid anhydride curing agent can be selected from any one of the following materials or their combinations: hexahydrophthalic anhydride (HHPA), methylhexahydrophthalic anhydride (MHHPA), methyltetrahydrophthalic anhydride (MTHPA), and methylnadic anhydride (MNA). The weight parts of the curing agent are between 85 - 110 parts. For example, 90 parts of MHHPA can be used as the curing agent, or a blend of 95 parts of MHHPA and HHPA can be used as the curing agent.

[0031] In the present invention, the accelerator can be selected from any one of the following materials or their combinations: tertiary amine accelerators, imidazoles, boroxine halide amine complexes, and organic zinc salts. The weight parts of the accelerator are between 0.01 - 1 part. For example, the accelerator can be 0.05 part, 0.1 part, 0.5 part, 1 part, etc. As a preferred embodiment, the accelerator includes 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) and benzyldimethylamine (BDMA).

[0032] Based on the above epoxy resin composition with low temperature conductivity activation energy, the present invention also provides a preparation method of an epoxy resin composition with low temperature conductivity activation energy, as Figure 1 shown, including the following steps:

[0033] Step 1: Blend the bifunctional epoxy resin and the high-functional epoxy resin in proportion to obtain an epoxy resin blend;

[0034] Step 2: Blend the epoxy resin blend, the curing agent, and the accelerator in proportion to obtain an epoxy resin composition;

[0035] Step 3: Mechanically stir the epoxy resin composition obtained in Step 2 and perform degassing treatment under a vacuum environment. The degassing time can be adjusted according to the weight of the composition to ensure that there are no obvious bubbles inside after the resin is cured.

[0036] Step 4: Pour the epoxy resin composition obtained in Step 3 into the preheated mold and cure it under gradient temperature conditions.

[0037] In this step, the temperature range of the gradient temperature conditions is 60 - 180°C. It can be continuous heating and curing, or multi-stage gradient curing. For example, it can be cured by linearly heating from 80°C to 160°C for 24 hours, or a combined curing system of curing at 100°C for 12 hours + curing at 140°C for 24 hours can be selected.

[0038] Step 5: Naturally cool the cured mold to room temperature, perform demolding treatment to obtain the finished product of the cured epoxy resin composition.

[0039] Through the above steps, a cured epoxy resin composition with a low temperature conductivity activation energy can be prepared. The direct current conductivity temperature activation energy of this cured epoxy resin composition is <0.85 eV, the glass transition temperature is 110 - 135°C, the power frequency dielectric constant is <3.5, the breakdown strength is >30 kV / mm, and the tensile strength is 60 - 80 MPa.

[0040] Based on the above epoxy resin composition with a low temperature conductivity activation energy, the present invention also proposes an application of the epoxy resin composition with a low temperature conductivity activation energy. The epoxy resin composition with a low temperature conductivity activation energy is applied to the casting and impregnation of the insulation core of a high-voltage DC dry bushing, and its reduced conductivity temperature dependence can improve the internal electric field distribution of the insulation core under large temperature gradient conditions.

[0041] In order to verify the effects of the present invention, the applicant uses the following examples and comparative examples for performance testing:

[0042] Example 1:

[0043] The components of the epoxy resin composition with a low temperature conductivity activation energy in this example are as follows: by weight, it includes 93 parts of bisphenol A epoxy resin (epoxy value 5.0 - 5.6 eq / kg), 7 parts of tetrafunctional epoxy resin 4,4-diaminodiphenylmethane tetraglycidylamine (TGDDM), 90 parts of methylhexahydrophthalic anhydride (MHHPA), and 0.1 part of accelerator benzyldimethylamine (BDMA).

[0044] In this example, the following method is used to prepare the cured epoxy resin composition:

[0045] First, weigh the corresponding mass parts of bisphenol A epoxy resin and TGDDM for blending, heat in a 60-degree water bath and mechanically stir for 30 minutes to ensure that TGDDM can be evenly mixed with bisphenol A, obtaining epoxy resin blend 1;

[0046] Then, weigh the corresponding mass parts of MHHPA curing agent and BDMA accelerator and compound them with blend 1, heat in a 60-degree water bath and mechanically stir for 1 hour to ensure that the epoxy resin, curing agent and accelerator can be evenly mixed, obtaining epoxy resin composition 1;

[0047] Next, subject the above composition to vacuum degassing treatment at 80 degrees for 1 hour to fully remove the possible bubbles in the formulation; meanwhile, preheat the epoxy resin mold at 100 degrees for 1 hour, where the mold has been treated with a mold release agent.

[0048] Then, pour the epoxy resin composition into the preheated mold under vacuum, place it in an oven for curing, adopt a two-stage curing process, cure at 100 degrees for 15 hours, and then raise the temperature to 140 degrees and cure for 20 hours.

[0049] Finally, after allowing the mold to cool naturally to room temperature, demold to obtain the cured epoxy resin product.

[0050] Example 2:

[0051] The components of the epoxy resin composition with low-temperature conductivity activation energy in this example are as follows: 90 parts by weight of bisphenol A epoxy resin (epoxy value 5.0 - 5.6 eq / kg), 10 parts of triglycidyl m-aminophenol (TGAP), 90 parts of methylhexahydrophthalic anhydride (MHHPA), and 0.1 part of accelerator benzyl dimethylamine (BDMA).

[0052] The process for preparing the cured epoxy resin composition in this example is the same as that in Example 1.

[0053] Example 3:

[0054] The components of the epoxy resin composition with low-temperature conductivity activation energy in this example are as follows: 70 parts by weight 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 m-aminophenol (TGAP), 90 parts of methylhexahydrophthalic anhydride (MHHPA), and 0.1 part of accelerator benzyl dimethylamine (BDMA).

[0055] The process for preparing the cured epoxy resin composition in this example is the same as that in Example 1.

[0056] Example 4:

[0057] The components of the epoxy resin composition with low-temperature conductivity activation energy in this example are as follows: by weight, it contains 90 parts of bisphenol A epoxy resin (epoxy value 5.0 - 5.6 eq / kg), 5 parts of tetrafunctional epoxy resin 4,4-diaminodiphenylmethane tetraglycidylamine (TGDDM), 5 parts of triglycidyl m-aminophenol (TGAP), 90 parts of methylhexahydrophthalic anhydride (MHHPA), and 0.1 part of accelerator benzyldimethylamine (BDMA).

[0058] The process for preparing the cured epoxy resin composition in this example is the same as that in Example 1.

[0059] Example 5:

[0060] The components of the epoxy resin composition with low-temperature conductivity activation energy in this example are as follows: by weight, it contains 90 parts of bisphenol A epoxy resin (epoxy value 5.0 - 5.6 eq / kg), 10 parts of tetrafunctional epoxy resin 4,4-diaminodiphenylmethane tetraglycidylamine (TGDDM), 85 parts of methyltetrahydrophthalic anhydride (MTHPA), and 0.1 part of accelerator benzyldimethylamine (BDMA).

[0061] The process for preparing the cured epoxy resin composition in this example is similar to that in Example 1, except that the curing regime is changed. The epoxy resin mold is preheated at 80 °C for 1 hour, and a two-stage curing process is adopted. It is cured at 80 °C for 12 hours, and then the temperature is raised to 130 °C for 24 hours.

[0062] Comparative Example 1:

[0063] A traditional casting formulation system for high-voltage dry-type bushings contains, by weight, 100 parts of bisphenol A epoxy resin (epoxy value 5.4 - 5.6 eq / kg), 90 parts of methylhexahydrophthalic anhydride (MHHPA), and 0.2 part of accelerator benzyldimethylamine (BDMA). The cured product of Comparative Example 1 is prepared by a traditional method.

[0064] Comparative Example 2:

[0065] A traditional casting formulation system for high-voltage dry-type bushings contains, by weight, 100 parts of bisphenol A epoxy resin (epoxy value 5.4 - 5.6 eq / kg), 85 parts of methyltetrahydrophthalic anhydride (MTHPA), and 0.2 part of accelerator benzyldimethylamine (BDMA). The cured product of Comparative Example 2 is prepared by a traditional method.

[0066] After the above tests, direct current conductivity tests and activation energy calculations are carried out respectively:

[0067] The three - electrode method is used to measure the direct - current conductivity of the cured product at different temperatures. The Arrhenius formula is used to linearly fit the temperature dependence of the conductivity, and the activation energy of the conductivity with respect to temperature is calculated. The calculation formula is as follows:

[0068]

[0069] where γ is the conductivity (S / m), γ0 is a constant related to the material properties (S / m), E a is the activation energy of the material conductivity (eV), q is the elementary charge amount (1.6×10 -19 ), k b is the Boltzmann constant 1.38×10 -23 (J / K), and T is the temperature (K).

[0070] Breakdown strength: It is tested in transformer oil using a sphere - sphere electrode, and is carried out with reference to the national standard GB / T 1408.1;

[0071] Tensile strength: It is tested using a universal electronic tensile testing machine, and is carried out with reference to the national standard GB / T 2567.

[0072] Glass transition temperature: It is measured by differential scanning calorimetry.

[0073] Power - frequency dielectric constant: It is obtained by measurement using a broadband dielectric spectrometer, and is carried out with reference to the national standard GB / T 1410.

[0074] The performance indexes obtained from the above tests are as follows Figure 2 and as shown in the following table:

[0075]

[0076] It can be seen from the above comparative tests that the epoxy cured product obtained according to the epoxy resin composition formula and preparation process of the present invention has excellent insulation, heat - resistance and mechanical properties. Its activation energy of direct - current conductivity with respect to temperature is < 0.85 eV, the glass transition temperature is 110 - 135 °C, the power - frequency dielectric constant is < 3.5, the breakdown strength is > 30 kV / mm, and the tensile strength is 60 - 80 MPa, meeting the application requirements of high - voltage DC dry - type bushings for different voltage levels and occasions.

[0077] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manners. Any other implementation manners obtained by those skilled in the art according to the technical solutions of the present invention also belong to the scope protected by the present invention.

Claims

1. Application of an epoxy resin composition with low temperature conductivity activation energy, characterized in that: The epoxy resin composition with low temperature conductivity activation energy is applied to the casting and impregnation of the insulation core of a high-voltage DC dry bushing, and the internal electric field distribution of the insulation core under large temperature gradient conditions is improved by reducing the temperature dependence of conductivity. The components and their weight parts of the epoxy resin composition with low temperature conductivity activation energy are as follows: 100 parts of epoxy resin blend, 85 - 110 parts of curing agent, and 0.01 - 1 part of accelerator; the epoxy resin blend uses bifunctional epoxy resin as the matrix and high-functional epoxy resin as the modifier. The high-functional epoxy resin is one or a combination of at least two of triglycidyl-m-aminophenol, triglycidyl-p-aminophenol, and 4,4'-diaminodiphenylmethane tetraglycidylamine.

2. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 1, characterized in that: The bifunctional epoxy resin is an aromatic or alicyclic epoxy resin, which contains two epoxy groups in its molecular chain, and its weight part is 85 - 97 parts; the weight part of the high-functional epoxy resin is 3 - 15 parts.

3. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 2, characterized in that: The bifunctional 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-epoxycyclohexanecarboxylate, and 1,6-bis(2,3-epoxypropoxy)naphthalene.

4. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 1, characterized in that: The room temperature viscosity of the epoxy resin blend is less than 10000 mPa·s, and the epoxy value is 4 - 6.5 eq / kg.

5. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 4, characterized in that: The room temperature viscosity range of the epoxy resin blend is 4000 - 6000 mPa·s, and the epoxy value range is 5.6 - 6.2 eq / kg.

6. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 1, characterized in that: The curing agent is an acid anhydride curing agent, and this acid anhydride curing agent is one or a combination of at least two of hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and methylnadic anhydride.

7. Use of the epoxy resin composition with low temperature conductivity activation energy according to claim 1, characterized in that: The accelerator is one or a combination of at least two of tertiary amine accelerators, imidazole, boron halide amine complex, and organic zinc salt.

Images