High-stability epoxy impregnating insulating paint and preparation method thereof

Abstract

The invention provides high-stability epoxy impregnating insulating paint, which is characterized in that the high-stability epoxy impregnating insulating paint is prepared from the following raw materials: epoxy resin, a diluent, a curing agent, modified fumed silica, an accelerant and an auxiliary agent, wherein the modified fumed silica is a product of hydroxylated fumed silica and partially grafted carboxymethyl cellulose. The preparation method of the high-stability epoxy impregnating insulating paint comprises the following steps: S1, carrying out hydroxylation treatment on fumed silica to obtain hydroxylated fumed silica; s2, mixing the hydroxylated fumed silica and carboxymethyl cellulose, heating and carrying out an ultrasonic reaction to obtain modified fumed silica; s3, blending and stirring the modified fumed silica and other components to obtain the high-stability epoxy impregnating insulating paint. The high-stability epoxy impregnating insulating paint has the characteristics of good stability and excellent insulating property, and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of composite materials, and mainly relates to a high-stability epoxy impregnated insulating varnish and a preparation method thereof. Background Art

[0002] Epoxy paint is a type of industrial coating that has developed rapidly in recent years. It has good physical and chemical properties. Its development can be traced back to the 20th century. With the advancement of chemical technology, the performance of epoxy paint has been continuously optimized and its application areas have been continuously expanded. Early epoxy paint was mainly used for anti-corrosion coatings, and later gradually developed into the fields of construction, automobiles, ships, aerospace, electrical equipment, instrumentation, etc. Generally speaking, coatings containing more epoxy groups in the components are collectively referred to as epoxy paints. Epoxy paints are generally composed of epoxy resins, curing agents, additives and other components, among which epoxy resins are the main components of epoxy paints.

[0003] Epoxy resin is a thermosetting resin with good mechanical properties and chemical stability. As the main component of epoxy paint, it determines the performance of epoxy paint. Although epoxy paint has good corrosion resistance, wear resistance, heat resistance, environmental protection, etc., some defects may occur during use and construction, such as: (1) Insufficient stability: Insufficient adhesion between the coating and the substrate, resulting in coating peeling; poor stain resistance, easy to be attached by dirt; poor weather resistance, easy to fade or bubble; poor impact resistance, easy to crack or peel; unstable viscosity, long-term storage at room temperature or short-term storage at high temperature is prone to a significant increase in viscosity; (2) Insufficient insulation: Epoxy paint is used in electrical equipment, instrumentation and other fields, which requires good insulation. New equipment has higher requirements for insulation, and it is necessary to further improve its insulation performance.

[0004] In summary, it is necessary to develop a new technical solution to solve the defects and shortcomings in the existing technology. Summary of the invention

[0005] The present invention provides a high-stability epoxy impregnated insulating varnish, which is prepared from epoxy resin, epoxy diluent, epoxy curing agent, modified fumed silica, additives and other components. The high-stability epoxy impregnated insulating varnish has good stability, including good viscosity stability, adhesion, stain resistance, weather resistance, impact resistance, etc., and also has excellent insulation and good application prospects.

[0006] One object of the present invention is to provide a high-stability epoxy impregnated insulating varnish, wherein the high-stability epoxy impregnated insulating varnish is composed of the following raw materials in parts by mass:

[0007]

[0008]

[0009] The modified fumed silica is a product of hydroxylated fumed silica partially grafted with carboxymethyl cellulose.

[0010] Furthermore, the particle size of the fumed silica is 5-80 nm.

[0011] Furthermore, the auxiliary agent is selected from one or more of a leveling agent, a defoaming agent, a UV absorber, a dispersant, and an antioxidant.

[0012] Furthermore, the leveling agent is selected from one or more of an organic silicon leveling agent, a polyether leveling agent, a polyester leveling agent, and a fluorinated leveling agent.

[0013] Furthermore, the defoamer is selected from one or more of an organosilicon defoamer, a polyether defoamer, and a fatty acid defoamer.

[0014] Furthermore, the ultraviolet absorber is selected from one or more of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, and benzophenone ultraviolet absorbers.

[0015] Furthermore, the dispersant is selected from one or more of polyether dispersants, polyacrylate dispersants, and inorganic salt dispersants.

[0016] Furthermore, the antioxidant is selected from one or more of phenolic antioxidants, phosphate antioxidants, sulfite antioxidants, metal complexes, and sulfide alcohol antioxidants.

[0017] Furthermore, the curing agent is a dicyandiamide complex.

[0018] Furthermore, the accelerator is a substituted urea accelerator.

[0019] Another object of the present invention is to provide a method for preparing the above-mentioned high-stability epoxy impregnated insulating varnish, the method for preparing the high-stability epoxy impregnated insulating varnish comprising the following steps:

[0020] S1, hydroxylating the fumed silica to obtain hydroxylated fumed silica;

[0021] S2, mixing hydroxylated fumed silica and carboxymethyl cellulose, heating and ultrasonically reacting the mixture to obtain modified fumed silica;

[0022] S3. Blending and stirring the modified fumed silica with other components to obtain a high-stability epoxy impregnated insulating varnish.

[0023] Furthermore, in step S1, the hydroxylation treatment is to activate the fumed silica with a mixed solution of concentrated sulfuric acid and hydrogen peroxide to obtain hydroxylated fumed silica.

[0024] Furthermore, the mass ratio of concentrated sulfuric acid to hydrogen peroxide is (60-80):(20-40), the activation treatment temperature is 70-80°C, and the time is 0.5-2h.

[0025] Furthermore, in step S2, the temperature of the heating ultrasonic reaction is 50-90°C and the time is 2-6h.

[0026] Furthermore, in step S2, the mass ratio of the hydroxylated fumed silica to the carboxymethyl cellulose is 1:(4-10).

[0027] Furthermore, in step S3, the stirring time is 0.5-1h.

[0028] The present invention has the following beneficial effects:

[0029] The high-stability epoxy impregnated insulating varnish provided by the present invention uses epoxy resin as a matrix and optimizes relevant properties by introducing modified fumed silica. The fumed silica is first hydroxylated to introduce a large number of hydroxyl groups on the surface of the fumed silica, and then the hydroxylated fumed silica is mixed with carboxymethyl cellulose to partially graft the carboxymethyl cellulose to obtain a modified fumed silica with a more regular surface. The compatibility of the modified fumed silica with the remaining components is also enhanced, so that it is evenly distributed in the matrix, which is conducive to forming a uniform and dense coating. The surface of the modified fumed silica has a large number of hydroxyl groups, which can generate intermolecular forces with the remaining components, improve its own dispersibility, and ultimately improve the performance of the product; and because the modified fumed silica is easily chemically cross-linked with the epoxy resin, the components are integrated to form a more stable structure, thereby further improving the stability and insulation of the product. DETAILED DESCRIPTION

[0030] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0031] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0032] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0033] The following raw materials are used in the embodiments of the present invention:

[0034] The epoxy resin is E44 epoxy resin;

[0035] The diluent is HK-66;

[0036] The curing agent is Dyhard 100S;

[0037] The accelerator is GLOC-300;

[0038] Fumed silica, particle size 5-80nm;

[0039] The auxiliary agent is sodium dodecyl sulfate and defoamer 2410AC in a mass ratio of 1:1.

[0040] Example 1

[0041] A high-stability epoxy impregnated insulating varnish, composed of the following raw materials in parts by mass:

[0042]

[0043]

[0044] The preparation method of the high-stability epoxy impregnated insulating varnish comprises the following steps:

[0045] S1, adding fumed silica to a mixture of concentrated sulfuric acid and hydrogen peroxide in a mass ratio of 70:30, heating to 80° C., reacting for 2 hours, filtering, washing, and drying to obtain hydroxylated fumed silica;

[0046] S2, using ethanol as solvent, blending hydroxylated fumed silica and carboxymethyl cellulose in a mass ratio of 1:5, heating to 85°C for ultrasonic reaction for 3 hours, filtering, washing, and drying to obtain modified fumed silica;

[0047] S3. According to the above mass fractions, the modified fumed silica is mixed with epoxy resin, diluent, curing agent, accelerator and auxiliary agent, and stirred evenly to obtain high-stability epoxy impregnated insulating varnish.

[0048] Example 2

[0049] A high-stability epoxy impregnated insulating varnish, composed of the following raw materials in parts by mass:

[0050]

[0051] The preparation method of the high-stability epoxy impregnated insulating varnish comprises the following steps:

[0052] S1, adding fumed silica to a mixture of concentrated sulfuric acid and hydrogen peroxide in a mass ratio of 70:30, heating to 80° C., reacting for 2 hours, filtering, washing, and drying to obtain hydroxylated fumed silica;

[0053] S2, using ethanol as solvent, blending hydroxylated fumed silica and carboxymethyl cellulose in a mass ratio of 1:5, heating to 85°C for ultrasonic reaction for 3 hours, filtering, washing, and drying to obtain modified fumed silica;

[0054] S3. According to the above mass fractions, the modified fumed silica is mixed with epoxy resin, diluent, curing agent, accelerator and auxiliary agent, and stirred evenly to obtain high-stability epoxy impregnated insulating varnish.

[0055] Example 3

[0056] A high-stability epoxy impregnated insulating varnish, composed of the following raw materials in parts by mass:

[0057]

[0058]

[0059] The preparation method of the high-stability epoxy impregnated insulating varnish comprises the following steps:

[0060] S1, adding fumed silica to a mixture of concentrated sulfuric acid and hydrogen peroxide in a mass ratio of 70:30, heating to 80° C., reacting for 2 hours, filtering, washing, and drying to obtain hydroxylated fumed silica;

[0061] S2, using ethanol as solvent, blending hydroxylated fumed silica and carboxymethyl cellulose in a mass ratio of 1:5, heating to 85°C for ultrasonic reaction for 3 hours, filtering, washing, and drying to obtain modified fumed silica;

[0062] S3. According to the above mass fractions, the modified fumed silica is mixed with epoxy resin, diluent, curing agent, accelerator and auxiliary agent, and stirred evenly to obtain high-stability epoxy impregnated insulating varnish.

[0063] Comparative Example

[0064] The difference between this comparative example and Example 1 is that the carboxymethyl cellulose in step S2 is replaced by an equal mass of lauric acid, and the other ingredients and preparation method are the same as those in Example 1.

[0065] Test Case

[0066] The samples prepared in Examples 1-3 and the comparative example were tested for stability and insulation after being cured into coatings.

[0067] Test Method

[0068] Stability: The viscosity test conditions are as follows: the coating is stored at room temperature for half a year and at 60°C for 48 hours, and the viscosity growth rates before and after the two conditions are compared; after the surface of the tinplate sheet is polished and cleaned, the sample coatings prepared in Examples 1-3 and the comparative example are coated respectively, and heat-cured at 150°C to obtain a coating; the viscosity growth rate, surface drying, thick layer curing, gel time, bonding strength, adhesion, impact resistance, and resistance to artificial climate acceleration are tested with reference to GB / T 15022.2, GB / T 9286, GB / T20624.1, and GB / T 14522 standards.

[0069] Insulation: The insulation properties of the samples prepared in Examples 1-3 and the comparative example were evaluated by testing their volume resistivity and electrical strength in accordance with standards such as GB / T 15022.2 Resin-based active composites for electrical insulation Part 2: Test methods.

[0070] The stability test results are shown in Table 1, and the insulation test results are shown in Table 2.

[0071] Table 1 Stability test results of samples prepared in Examples 1-3 and Comparative Examples

[0072]

[0073]

[0074] Table 2 Insulation test results of samples prepared in Examples 1-3 and Comparative Examples

[0075]

[0076] It can be seen from Table 1 and Table 2 that the performance of Examples 1-3 is significantly better than that of the comparative example. This is because the carboxymethyl cellulose in step S2 is replaced by an equal mass of lauric acid in the comparative example. Lauric acid cannot provide a large number of hydroxyl groups like the carboxymethyl cellulose in the example, and the intermolecular force with the remaining components is weak, and it cannot be cross-linked with the epoxy resin. The synergistic effect between the various components is reduced, which ultimately leads to a decrease in the stability, strength and other properties of the coating.

[0077] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0078] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high stability epoxy impregnated insulating varnish, characterized in that: The high stability epoxy impregnated insulating varnish is composed of the following raw materials in parts by mass: The modified fumed silica is a product of hydroxylated fumed silica partially grafted with carboxymethyl cellulose.

2. The high stability epoxy impregnated insulating varnish according to claim 1, characterized in that: The particle size of the fumed silica is 5-80 nm.

3. The high stability epoxy impregnated insulating varnish according to claim 1, characterized in that: The auxiliary agent is selected from one or more of a leveling agent, a defoaming agent, a UV absorber, a dispersant, and an antioxidant.

4. The high stability epoxy impregnated insulating varnish according to claim 1, characterized in that: The curing agent is a dicyandiamide complex.

5. The high stability epoxy impregnated insulating varnish according to claim 1, characterized in that: The accelerator is a substituted urea accelerator.

6. The method for preparing the high-stability epoxy impregnated insulating varnish according to any one of claims 1 to 5, characterized in that: The preparation method of the high-stability epoxy impregnated insulating varnish comprises the following steps: S1, hydroxylating the fumed silica to obtain hydroxylated fumed silica; S2, mixing hydroxylated fumed silica and carboxymethyl cellulose, heating and ultrasonically reacting the mixture to obtain modified fumed silica; S3. Blending and stirring the modified fumed silica with other components to obtain a high-stability epoxy impregnated insulating varnish.

7. The method for preparing the high-stability epoxy impregnated insulating varnish according to claim 6, characterized in that: In step S1, the hydroxylation treatment is to activate the fumed silica with a mixed solution of concentrated sulfuric acid and hydrogen peroxide to obtain hydroxylated fumed silica.

8. The method for preparing the high-stability epoxy impregnated insulating varnish according to claim 7, characterized in that: The mass ratio of concentrated sulfuric acid to hydrogen peroxide is (60-80):(20-40), the activation treatment temperature is 70-80°C, and the time is 0.5-2h.

9. The method for preparing the high-stability epoxy impregnated insulating varnish according to claim 6, characterized in that: In step S2, the temperature of the heating ultrasonic reaction is 50-90°C and the time is 2-6h.

10. The method for preparing the high-stability epoxy impregnated insulating varnish according to claim 6, characterized in that: In step S2, the mass ratio of the hydroxylated fumed silica to the carboxymethyl cellulose is 1:(4-10).

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