Epoxy resin composition and preparation method thereof as well as electrical insulation part and preparation method thereof

Abstract

The invention provides an epoxy resin composition and a preparation method thereof, and an electrical insulating part and a preparation method thereof, and relates to the technical field of epoxy resin. According to the epoxy resin composition provided by the invention, the aromatic amine curing agent is used, the conventional imidazole accelerant is added, and the flexible epoxy resin is added to be matched with the imidazole accelerant, so that the tank storage time and the high-temperature reactivity of the epoxy resin composition can be controlled, and the material performance of the obtained epoxy resin composition is equivalent to that of a formula in which an anhydride curing agent is added; the prepared gel has good toughness and long gelation time, and does not need to add an expensive cage-shaped imidazole accelerant, so that the cost is saved.

Description

Technical Field

[0001] The present application relates to the technical field of epoxy resins, and in particular to an epoxy resin composition and a preparation method thereof, an electrical insulating component and a preparation method thereof. Background Art

[0002] At present, most epoxy resin compositions used for electrical insulation protection use anhydrides as curing agents. Due to the increasingly stringent regulatory framework for chemicals, some anhydrides have been listed on the SVHC (Substances of Very High Concern) candidate list stipulated in the EU Regulation "Registration, Evaluation, Authorization and Restriction of Chemicals" (REACH). It is very likely that these anhydride substances will be banned in the coming years, so the demand for non-anhydride curing agents will become more and more urgent.

[0003] Amine curing agents can also be used to cure epoxy resins, but amine curing agents are too reactive to be used well in electrical casting or packaging applications. There are two reasons for this: first, epoxy resins and amine curing agents generally react quickly, which cannot meet the requirements of automatic pressure gel injection technology (APG) for tank storage time; second, amine curing agents release a large amount of heat, which can cause the mechanical properties of thermosetting materials to deteriorate, or even cause thermal decomposition of thermosetting materials.

[0004] The prior art with patent publication number CN107636039A solves the problems of storage and reactivity by adding caged imidazole accelerators. The insulating products prepared with such materials show good mechanical, electronic and dielectric properties. However, caged imidazole accelerators are currently only produced by Nippon Soda Japan, and are expensive and difficult to obtain in the market. Summary of the invention

[0005] The purpose of the present application is to provide an epoxy resin composition and a preparation method thereof, an electrical insulating component and a preparation method thereof, in order to solve the problem that the existing epoxy resin composition requires a caged imidazole accelerator when using an amine curing agent.

[0006] To achieve the above objectives, the present application provides an epoxy resin composition, the raw materials of which, by mass, include: 92-99 parts of epoxy resin, 1-8 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1-1.25 parts of imidazole accelerator and 190-236 parts of filler.

[0007] In some embodiments, the raw materials include, by weight, 93-96 parts of epoxy resin, 4-7 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1-1.25 parts of imidazole accelerator and 196-216 parts of filler.

[0008] In some embodiments, the epoxy resin includes any one of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, alicyclic epoxy resins, multi-functional special epoxy resins, and hydrogenated bisphenol A epoxy resins.

[0009] In some embodiments, the flexible epoxy resin includes any one of polyurethane-modified epoxy resins and carboxyl-terminated nitrile rubber-modified epoxy resins.

[0010] In some embodiments, the aromatic amine curing agent includes diethyltoluenediamine.

[0011] In some embodiments, the imidazole accelerator includes any one of 1-alkylimidazoles and 2-ethyl-4-methylimidazole;

[0012] Optionally, the 1-alkylimidazole includes any one of 1-methylimidazole, 1-ethylimidazole, 1-propylimidazole, 1-butylimidazole, 1-pentylimidazole, 1-hexylimidazole, 1-octylimidazole, 1-decylimidazole, 1-dodecylimidazole, 1-tetradecylimidazole, 1-hexadecylimidazole, and 1-octadecylimidazole.

[0013] In some embodiments, the filler includes silica powder;

[0014] Optionally, the D50 of the silica powder is 20 - 30 μm.

[0015] The present application also provides a method for preparing the above epoxy resin composition, including:

[0016] Weigh the epoxy resin, flexible epoxy resin, aromatic amine curing agent, and imidazole accelerator in proportion, put them into a stirrer for mixing, then add the corresponding proportion of filler, disperse evenly, evacuate, and cure and mold at 120 - 180 °C to obtain the epoxy resin composition.

[0017] The present application also provides a method for preparing an electrical insulation part, using the epoxy resin composition as described above.

[0018] The present application also provides an electrical insulation part, which is prepared by the above method for preparing an electrical insulation part.

[0019] Compared with the prior art, the beneficial effects of the present application include:

[0020] The epoxy resin composition provided by the present application uses an aromatic amine curing agent and adds a conventional imidazole accelerator. By adding a flexible epoxy resin and matching it with an imidazole accelerator, the pot life and high-temperature reactivity of the epoxy resin composition can be controlled. The material properties of the obtained epoxy resin composition are comparable to those of the formulation with an acid anhydride curing agent, with good toughness, long gel time, and no need to add expensive cage-shaped imidazole accelerators, saving costs. Detailed implementation manners

[0021] As used herein, the terms:

[0022] "Prepared from" is synonymous with "comprising". As used herein, the terms "comprising", "including", "having", "containing", or any other variation thereof, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus containing the listed elements need not be limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0023] The conjunctive "consisting of" excludes any unstated element, step, or component. If used in a claim, this phrase will render the claim closed, excluding materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the claim body rather than immediately following the subject, it only limits the elements described in that clause; other elements are not excluded from the claim as a whole.

[0024] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any range upper limit or preferred value with any range lower limit or preferred value, whether or not the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted to include the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described herein, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range.

[0025] In these examples, unless otherwise specified, the parts and percentages are by mass.

[0026] "Parts by mass" refers to the basic measurement unit representing the mass ratio relationship of multiple components. 1 part can represent any unit mass, such as 1 g or 2.689 g, etc. If we say that the mass part of component A is a parts and the mass part of component B is b parts, it means the mass ratio of component A to component B is a:b. Or, it means the mass of component A is aK and the mass of component B is bK (K is any number representing a multiple factor). It should not be misunderstood that, different from the number of mass parts, the sum of the mass parts of all components is not limited to 100 parts.

[0027] "And / or" is used to indicate that either or both of the stated circumstances may occur. For example, A and / or B includes (A and B) and (A or B).

[0028] The present application provides an epoxy resin composition. In terms of parts by mass, its raw materials include: 92 - 99 parts of epoxy resin, 1 - 8 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1 - 1.25 parts of imidazole accelerator, and 190 - 236 parts of filler.

[0029] The epoxy resin composition provided by the present application uses an aromatic amine curing agent and adds a conventional imidazole accelerator. By adding a flexible epoxy resin in combination with the imidazole accelerator, the pot life and high - temperature reactivity of the epoxy resin composition can be controlled. The material properties of the obtained epoxy resin composition are comparable to those of the formulation with an acid anhydride curing agent, with good toughness, long gel time, and do not require adding expensive cage - type imidazole accelerators, thus saving costs.

[0030] Among them, the epoxy resin can be, for example, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, 97 parts, 98 parts, 99 parts, or any value between 92 - 99 parts; the flexible epoxy resin can be, for example, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, or any value between 1 - 8 parts; the filler can be, for example, 190 parts, 191 parts, 192 parts, 193 parts, 194 parts, 195 parts, 196 parts, 200 parts, 205 parts, 210 parts, 215 parts, 220 parts, 225 parts, 230 parts, 236 parts, or any value between 190 - 236 parts.

[0031] In some embodiments, in terms of parts by mass, its raw materials include: 93 - 96 parts of epoxy resin, 4 - 7 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1 - 1.25 parts of imidazole accelerator, and 196 - 216 parts of filler.

[0032] In some embodiments, the epoxy resin includes any one of glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, alicyclic epoxy resins, multi - functional special epoxy resins, and hydrogenated bisphenol A epoxy resins.

[0033] Among them, glycidyl ether epoxy resins are the most common type, usually prepared by reacting polyphenols (such as bisphenol A, bisphenol F, or bisphenol S) with epichlorohydrin. Glycidyl ether epoxy resins contain a glycidyl ether structure, and the most representative one is bisphenol A - type epoxy resin. Other main varieties include tetrabromobisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, etc.

[0034] Glycidyl ester epoxy resins are obtained by reacting dibasic or polybasic carboxylic acids with epichlorohydrin and removing hydrogen chloride. Such resins usually have good weather resistance. The reaction activity of such epoxy resins is relatively high, and the gel time is only about half that of bisphenol A epoxy resins. Such resins have high bonding strength, and the cured materials have excellent mechanical properties.

[0035] Glycidyl amine epoxy resins are the products of the reaction of polyamines with epichlorohydrin. Such resins perform excellently in terms of heat resistance and mechanical properties. Such epoxy resins have multiple functional groups, which increases the crosslinking density. Due to the high crosslinking and the presence of aromatic rings in their molecular structure, the heat resistance of such epoxy resins is better than that of general epoxy resins.

[0036] Alicyclic epoxy resins are synthesized from alicyclic compounds, have good stability, high safety performance, and excellent properties at high temperatures. The epoxy groups of alicyclic epoxy resins are directly connected to the alicyclic ring. After curing, they have a large crosslinking density and a tight rigid structure, so they have a high heat resistance temperature. Since there is no benzene ring in the molecular structure, alicyclic epoxy resins have good weather resistance and anti-yellowing properties. Epichlorohydrin is not used in the synthesis process, so there are no by-products such as chloride ions and sodium ions, and they have better dielectric properties. The viscosity of alicyclic epoxy resins is relatively small, which is convenient for casting and potting operations, and they have good processability.

[0037] Multi-functional group special epoxy resins are a type of epoxy resins with multiple reactive functional groups, which are usually used to improve the performance and adaptability of materials. Multi-functional group special epoxy resins have a high crosslinking density after curing, which enables them to maintain excellent mechanical properties and insulation properties at high temperatures.

[0038] Hydrogenated bisphenol A epoxy resin is a special epoxy resin, which can be obtained by the addition reaction of bisphenol A epoxy resin with hydrogen under the action of a catalyst. Hydrogenated bisphenol A epoxy resin has good weather resistance, chemical resistance, electrical insulation properties and other characteristics.

[0039] In some embodiments, the flexible epoxy resin includes any one of polyurethane-modified epoxy resin and carboxyl-terminated nitrile rubber-modified epoxy resin.

[0040] Among them, polyurethane-modified epoxy resin is a high-performance material obtained by combining polyurethane and epoxy resin. It combines the advantages of both and enhances the performance of the material. Polyurethane-modified epoxy resin has good wear resistance, chemical corrosion resistance and impact resistance. It has high strength and stiffness, can withstand large loads and deformations, and at the same time has excellent durability and anti-aging properties.

[0041] Carboxyl-terminated butadiene acrylonitrile rubber modified epoxy resin (CTBN modified epoxy resin) is a material obtained by adding carboxyl-terminated butadiene acrylonitrile rubber (CTBN) as a toughening agent to epoxy resin to improve the toughness of epoxy resin. CTBN has a good toughening effect on epoxy resin. As the content of CTBN increases, the tensile strength of the blend and prepolymer decreases, the elongation at break first increases and then decreases, and the impact strength gradually increases, indicating that CTBN has a toughening effect on epoxy resin.

[0042] In some embodiments, the aromatic amine curing agent includes diethyltoluenediamine.

[0043] Among them, diethyltoluenediamine is a liquid, low-viscosity, low-toxic aromatic amine curing agent with a fast reaction rate, hydrolysis resistance, and heat resistance, which can improve the strength and hydrolysis resistance of products.

[0044] In some embodiments, the imidazole accelerator includes any one of 1-alkylimidazole and 2,4-dimethylimidazole.

[0045] Optionally, the 1-alkylimidazole includes any one of 1-methylimidazole, 1-ethylimidazole, 1-propylimidazole, 1-butylimidazole, 1-pentylimidazole, 1-hexylimidazole, 1-octylimidazole, 1-decylimidazole, 1-dodecylimidazole, 1-tetradecylimidazole, 1-hexadecylimidazole, and 1-octadecylimidazole

[0046] In some embodiments, the filler includes silica powder; optionally, the D50 of the silica powder is 20-30 um.

[0047] Silica powder is a silica powder material obtained by subjecting natural quartz (SiO2) or fused quartz (non-crystalline SiO2 obtained by high-temperature melting and cooling of natural quartz) to a series of processing treatments. It has the characteristics of being non-toxic, odorless, and pollution-free, as well as excellent properties such as high heat resistance, high insulation, low linear expansion coefficient, and good thermal conductivity. The classification of silica powder includes fused silica powder, crystalline silica powder, active silica powder, cristobalite silica powder, etc.

[0048] This application also provides a preparation method of the above epoxy resin composition, including:

[0049] Weigh epoxy resin, flexible epoxy resin, aromatic amine curing agent, and imidazole accelerator according to the ratio, put them into a stirrer for mixing, then add the corresponding proportion of filler, disperse evenly, evacuate, and cure and mold at 120-180 °C to obtain the epoxy resin composition.

[0050] Among them, the curing temperature can be, for example, 120 °C, 130 °C, 140 °C, 150 °C, 160 °C, 170 °C, 180 °C, or any value between 120-180 °C.

[0051] The present application also provides a method for preparing an electrical insulating component, using the epoxy resin composition as described above.

[0052] The present application also provides an electrical insulating component, which is prepared by the above-mentioned method for preparing the electrical insulating component.

[0053] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0054] The materials used in the following examples and comparative examples are described as follows:

[0055] CYD-127E: bisphenol A epoxy resin, epoxy equivalent 180-186, purchased from: China Petrochemical Group Baling Petrochemical Co., Ltd.

[0056] JEF0240: flexible epoxy resin, epoxy value 0.25-035, purchased from: Hangmo New Materials Group Co., Ltd.

[0057] DETDA: diethyltoluenediamine, purchased from: Zhangjiagang Yarui Chemical Co., Ltd.

[0058] 2E4MZ: 2-ethyl-4-methylimidazole, purchased from Nanjing Chemical Reagent Co., Ltd.

[0059] DC1265: Silica powder, purchased from Jiangsu Lianrui New Materials Co., Ltd.

[0060] Example 1

[0061] Example 1 provides an epoxy resin composition, the raw materials of which, by mass, include: 95 parts of epoxy resin CYD-127E, 5 parts of flexible epoxy resin JEF0240, 24 parts of aromatic amine curing agent DETDA, 1.25 parts of imidazole accelerator 2E4MZ and 196 parts of filler DC1265.

[0062] Example 1 also provides a method for preparing an epoxy resin composition, comprising: at room temperature, weighing CYD-127E, JEF0240, DETDA, and 2E4MZ in proportion and placing them in a stirrer, stirring for 10 minutes, then adding a corresponding proportion of filler DC1265, dispersing and stirring for 1 hour, vacuuming for 1 hour, and then curing and molding at 140°C to obtain the epoxy resin composition of Example 1.

[0063] Example 2

[0064] Example 2 provides an epoxy resin composition, whose raw materials, measured by mass, include: 95 parts of epoxy resin CYD-127E, 5 parts of flexible epoxy resin JEF0240, 24 parts of aromatic amine curing agent DETDA, 1 part of imidazole accelerator 2E4MZ and 196 parts of filler DC1265.

[0065] The preparation method of the epoxy resin composition of Example 2 is the same as that of Example 1, which will not be repeated here.

[0066] Example 3

[0067] Example 3 provides an epoxy resin composition, whose raw materials, measured by mass, include: 93 parts of epoxy resin CYD-127E, 7 parts of flexible epoxy resin JEF0240, 24 parts of aromatic amine curing agent DETDA, 1 part of imidazole accelerator 2E4MZ and 196 parts of filler DC1265.

[0068] The preparation method of the epoxy resin composition of Example 3 is the same as that of Example 1, which will not be repeated here.

[0069] Comparative Example 1

[0070] The epoxy resin composition of Comparative Example 1 is the solution of Example 1b in the prior art CN107636039A.

[0071] Comparative Example 2

[0072] The epoxy resin composition of Comparative Example 2 is the solution of Comparative Example 5b in the prior art CN107636039A.

[0073] Comparative Example 3

[0074] Comparative Example 3 provides an epoxy resin composition, whose raw materials, measured by mass, include: 90 parts of epoxy resin CYD-127E, 10 parts of flexible epoxy resin JEF0240, 24 parts of aromatic amine curing agent DETDA, 1 part of imidazole accelerator 2E4MZ and 196 parts of filler DC1265.

[0075] The preparation method of the epoxy resin composition of Comparative Example 3 is the same as that of Example 1, which will not be repeated here.

[0076] Comparative Example 4

[0077] Comparative Example 4 provides an epoxy resin composition, the raw materials of which, in parts by mass, include: 100 parts of epoxy resin CYD-127E, 24 parts of aromatic amine curing agent DETDA, 1 part of imidazole accelerator 2E4MZ and 196 parts of filler DC1265.

[0078] The preparation method of the epoxy resin composition of Comparative Example 4 is the same as that of Example 1, and will not be elaborated here.

[0079] The performance test results of the epoxy resin compositions of Examples 1 to 3 and Comparative Examples 3 to 4 are shown in Table 1.

[0080] Table 1 Performance test results of the epoxy resin compositions of each example and comparative example

[0081]

[0082] According to Table 1, the solution of the present application adopts the method of adding flexible epoxy resin, and the pot life and high-temperature reactivity of the formulation can be controlled by adding imidazole accelerators. The material properties obtained are comparable to those of the anhydride-based epoxy resin composition formulation of Comparative Example 2.

[0083] Referring to the anhydride-based epoxy resin composition formulation of Comparative Example 2, the gel time at 140 °C of the present application is within a reasonable range (suitable for the high-temperature reactivity of the APG process), and the pot life at a certain temperature is also close to that of the anhydride-based epoxy resin composition formulation (the gel time at 80 °C is close to 120 min). The gel time at 140 °C of Comparative Example 3 is too long and the reaction activity is insufficient. The reactivity of Comparative Example 4 at 140 °C is acceptable, but the gel time at 80 °C is too short, indicating that the pot life of its composition is insufficient.

[0084] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

[0085] In addition, those skilled in the art can understand that although some embodiments herein include certain features included in other embodiments but not other features, the combination of the features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims above, any one of the claimed embodiments can be used in any combination. The information disclosed in this background art section is only intended to deepen the understanding of the overall background art of the present application, and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those skilled in the art.

Claims

1. An epoxy resin composition, characterized in that The raw materials include, by weight, 92-99 parts of epoxy resin, 1-8 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1-1.25 parts of imidazole accelerator and 190-236 parts of filler.

2. The epoxy resin composition according to claim 1, characterized in that The raw materials include, by weight, 93-96 parts of epoxy resin, 4-7 parts of flexible epoxy resin, 24 parts of aromatic amine curing agent, 1-1.25 parts of imidazole accelerator and 196-216 parts of filler.

3. The epoxy resin composition according to claim 1 or 2, characterized in that The epoxy resin includes any one of glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, alicyclic epoxy resin, multifunctional special epoxy resin, and hydrogenated bisphenol A epoxy resin.

4. The epoxy resin composition according to claim 1 or 2, characterized in that The flexible epoxy resin includes any one of polyurethane modified epoxy resin and carboxyl-terminated nitrile rubber modified epoxy resin.

5. The epoxy resin composition according to claim 1 or 2, characterized in that: The aromatic amine curing agent includes diethyltoluenediamine.

6. The epoxy resin composition according to claim 1 or 2, characterized in that: The imidazole accelerator includes any one of 1-alkylimidazole and 2-ethyl-4-methylimidazole; Optionally, the 1-alkyl imidazole includes any one of 1-methyl imidazole, 1-ethyl imidazole, 1-propyl imidazole, 1-butyl imidazole, 1-pentyl imidazole, 1-hexyl imidazole, 1-octyl imidazole, 1-decyl imidazole, 1-dodecyl imidazole, 1-tetradecyl imidazole, 1-hexadecyl imidazole, and 1-octadecyl imidazole.

7. The epoxy resin composition according to claim 1 or 2, characterized in that: The filler includes silicon powder; Optionally, the D50 of the silicon micropowder is 20-30 um.

8. A method for preparing the epoxy resin composition according to any one of claims 1 to 7, characterized in that: include: Epoxy resin, flexible epoxy resin, aromatic amine curing agent and imidazole accelerator are weighed in proportion and put into a stirrer for mixing, and then fillers in corresponding proportion are added and dispersed evenly, vacuumized, and cured at 120-180° C. to obtain the epoxy resin composition.

9. A method for preparing an electrical insulating component, characterized in that: Use of the epoxy resin composition according to any one of claims 1 to 7.

10. An electrical insulating member, characterized in that: The electrical insulating component is prepared by the method for preparing the electrical insulating component according to claim 9.

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