High-stability epoxy impregnating insulating paint and preparation method thereof

Abstract

The application provides a high-stability epoxy impregnated insulating paint, characterized in that the high-stability epoxy impregnated insulating paint is composed of the following raw materials: epoxy resin, diluent, curing agent, modified fumed silica, accelerator and auxiliary agent; wherein the modified fumed silica is a product of partially grafted carboxymethyl cellulose and hydroxylated fumed silica; and the preparation method of the high-stability epoxy impregnated insulating paint comprises the following steps: S1, hydroxylating fumed silica to obtain hydroxylated fumed silica; S2, mixing the hydroxylated fumed silica and carboxymethyl cellulose, and heating and ultrasonically reacting to obtain modified fumed silica; and S3, blending the modified fumed silica with the remaining components and stirring to obtain the high-stability epoxy impregnated insulating paint. The high-stability epoxy impregnated insulating paint has the characteristics of good stability and excellent insulating performance, and has a good application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite materials, and mainly relates to a high-stability epoxy impregnated insulating paint and a preparation method thereof. BACKGROUND

[0002] Epoxy paint is an industrial coating that has developed rapidly in recent years, has good physical and chemical properties, and its development can be traced back to the 20th century. With the progress of chemical technology, the performance of epoxy paint is continuously optimized, and the application field is continuously expanded. Early epoxy paint was mainly used for anticorrosive coating, and later gradually developed to the fields of building, automobile, ship, aerospace, electrical equipment, instruments and meters, etc. Generally speaking, coatings containing a large number of epoxy groups in the components are collectively referred to as epoxy paint. Epoxy paint is generally composed of epoxy resin, curing agent, additives and other components, among which, epoxy resin is the main component of epoxy paint.

[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 and other properties, some defects may occur during use and construction, such as: (1) insufficient stability: the adhesion between the coating and the substrate is insufficient, resulting in peeling of the coating; poor stain resistance, easy to be attached by dirt; poor weather resistance, easy to fade or blister; poor impact resistance, easy to appear cracks or peeling; unstable viscosity, easy to appear obvious viscosity increase after long-term storage at room temperature or short-term storage at high temperature; (2) insufficient insulation: epoxy paint applied to electrical equipment, instruments and meters requires good insulation, and new equipment requires higher insulation, so it is necessary to further improve its insulation performance.

[0004] In view of the above, it is necessary to develop a new technical scheme to solve the defects and deficiencies in the prior art. SUMMARY

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

[0006] An object of the present application is to provide a high-stability epoxy impregnated insulating paint, which is composed of the following raw materials in mass fraction:

[0007]

[0008]

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

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

[0011] Further, the auxiliary agent is selected from one or more of a leveling agent, a defoaming agent, an ultraviolet absorber, a dispersing agent, and an antioxidant.

[0012] Further, the leveling agent is selected from one or more of a silicone leveling agent, a polyether leveling agent, a polyester leveling agent, and a fluorinated leveling agent.

[0013] Further, the defoaming agent is selected from one or more of a silicone defoaming agent, a polyether defoaming agent, and a fatty acid defoaming agent.

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

[0015] Further, the dispersing agent is selected from one or more of a polyether dispersing agent, a polyacrylate dispersing agent, and an inorganic salt dispersing agent.

[0016] Further, the antioxidant is selected from one or more of a phenolic antioxidant, a phosphate ester antioxidant, a sulfite antioxidant, a metal complex, and a sulfurized alcohol antioxidant.

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

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

[0019] Another object of the present application is to provide a preparation method of the high-stability epoxy impregnation insulating paint, which comprises the following steps:

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

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

[0022] S3, blending the modified fumed silica with the remaining components and stirring to obtain the high-stability epoxy impregnation insulating paint.

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

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

[0025] Further, in step S2, the heating ultrasonic reaction temperature is 50-90℃, and the time is 2-6h.

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

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

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

[0029] The high-stability epoxy impregnating insulating paint provided by the present application takes epoxy resin as a matrix and optimizes the related performance 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 blended and reacted with carboxymethyl cellulose to make the hydroxylated fumed silica partially graft carboxymethyl cellulose, so that the modified fumed silica has a more regular surface and the compatibility of the modified fumed silica with the remaining components is enhanced, so that the modified fumed silica is uniformly distributed in the matrix, which is conducive to the formation of a uniform and dense coating, and the surface of the modified fumed silica has a large number of hydroxyl groups, which can produce intermolecular forces with the remaining components, improve the dispersibility of the modified fumed silica, and ultimately improve the performance of the product; and the modified fumed silica is easy to chemically crosslink with the epoxy resin, so that 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 solutions of the present application, the following examples are listed. The raw materials, reactions and post-treatment methods appearing in the examples are all common raw materials on the market and technical means well known to those skilled in the art, unless otherwise stated.

[0031] The words "preferred", "preferably", "more preferred" and the like in the present application refer to the embodiments of the present application which can provide certain beneficial effects in certain cases. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present application.

[0032] It should be understood, that, except in any operating example, or otherwise indicated herein, such as amounts of ingredients employed in the specification and claims, or all numbers such as amount, weight, percentage, are stated in their approximation and terminology of the art, and should be understood to be modified in all instances by the term "about". Numerical parameters set forth in the specification and associated claims are approximations that can vary depending upon the desired properties sought to be obtained by the present application.

[0033] The raw materials used in the embodiments of the present application are as follows:

[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] The fumed silica has a particle size of 5-80 nm;

[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 impregnation insulating paint is composed of raw materials in the following mass fractions:

[0042]

[0043]

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

[0045] S1, the fumed silica is added into a mixture of concentrated sulfuric acid and hydrogen peroxide in a mass ratio of 70:30, heated to 80℃, and reacted for 2h, filtered, washed, and dried to obtain hydroxylated fumed silica;

[0046] S2, the hydroxylated fumed silica and carboxymethyl cellulose in a mass ratio of 1:5 are blended with ethanol as a solvent, heated to 85℃, and ultrasonically reacted for 3h, filtered, washed, and dried to obtain modified fumed silica;

[0047] S3, the modified fumed silica is blended with the epoxy resin, the diluent, the curing agent, the accelerator, and the auxiliary agent in the above-mentioned mass fractions, and stirred uniformly to obtain the high-stability epoxy impregnation insulating paint.

[0048] Example 2

[0049] A high-stability epoxy impregnating insulating paint is prepared from the following raw materials in mass fractions:

[0050]

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

[0052] S1, adding fumed silica into a mixed solution of concentrated sulfuric acid and hydrogen peroxide with a mass ratio of 70:30, heating to 80°C, reacting for 2h, filtering, washing, and drying to obtain hydroxylated fumed silica;

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

[0054] S3, blending the modified fumed silica with epoxy resin, diluent, curing agent, accelerator, and auxiliary agent in the above mass fractions, stirring uniformly to obtain the high-stability epoxy impregnating insulating paint.

[0055] Example 3

[0056] A high-stability epoxy impregnating insulating paint is prepared from the following raw materials in mass fractions:

[0057]

[0058]

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

[0060] S1, adding fumed silica into a mixed solution of concentrated sulfuric acid and hydrogen peroxide with a mass ratio of 70:30, heating to 80°C, reacting for 2h, filtering, washing, and drying to obtain hydroxylated fumed silica;

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

[0062] S3, blending the modified fumed silica with epoxy resin, diluent, curing agent, accelerator, and auxiliary agent in the above mass fractions, stirring uniformly to obtain the high-stability epoxy impregnating insulating paint.

[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 other components and preparation methods are the same as those of Example 1.

[0065] Test Example

[0066] The stability and insulation of the samples prepared in Test Examples 1-3 and Comparative Examples after curing into a coating layer were tested.

[0067] Test Method

[0068] Stability: The test conditions for viscosity were that the paint was stored at room temperature for half a year and at 60°C for 48h, and the viscosity growth rate before and after the two conditions was compared; the surface of a tin plate was polished and cleaned, and then the paint of the samples prepared in Test Examples 1-3 and Comparative Examples was coated thereon, and heat curing was performed at 150°C to obtain a coating layer; the viscosity growth rate, surface dryness, thick layer curing, gel time, bonding strength, adhesion, impact resistance, and artificial climate resistance were tested in accordance with the standards of GB / T 15022.2, GB / T 9286, GB / T 20624.1, and GB / T 14522.

[0069] Insulation: The samples prepared in Test Examples 1-3 and Comparative Examples were tested for volume resistivity and electrical strength in accordance with the standards of GB / T 15022.2 Electrical Insulating Resin-Based Active Compound Part 2: Test Method, etc., to evaluate their insulation.

[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 Test Examples 1-3 and Comparative Examples

[0072]

[0073]

[0074] Table 2 Insulation Test Results of Samples Prepared in Test Examples 1-3 and Comparative Examples

[0075]

[0076] As can be seen from Tables 1 and 2, the performance of Test Examples 1-3 is significantly better than that of Comparative Examples, because the carboxymethyl cellulose in step S2 of Comparative Examples is replaced by lauric acid of the same mass, and lauric acid cannot provide as many hydroxyl groups as carboxymethyl cellulose in Test Examples, has weaker intermolecular forces with the remaining components, and cannot crosslink with the epoxy resin, so the synergistic effect between the components is reduced, and finally the stability and strength of the coating layer are reduced.

[0077] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other embodiments without departing from the spirit or essential characteristics of the application. The embodiments should, therefore, be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

[0078] Furthermore, it should be understood that although the description is made on embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and a person skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be combined appropriately to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A highly stable epoxy impregnated insulating varnish, characterized in that, The high-stability epoxy impregnated insulating varnish is composed of the following raw materials in parts by weight: 55-70 parts epoxy resin 10-30 parts of diluent 5-15 parts of curing agent 3-5 parts of modified fumed silica 1-3 parts of accelerator 1-2 parts of auxiliary agent; The modified fumed silica is a product of hydroxylated fumed silica partially grafted with carboxymethyl cellulose. The preparation method of the high-stability epoxy impregnated insulating varnish includes the following steps: S1. Hydroxylated fumed silica is obtained by hydroxylating fumed silica. S2. Hydroxylated fumed silica and carboxymethyl cellulose are mixed and heated under ultrasonication to obtain modified fumed silica. S3. Mix and stir the modified fumed silica with the remaining components to obtain a highly stable epoxy impregnated insulating varnish. The hydroxylation treatment involves activating fumed silica with a mixture of concentrated sulfuric acid and hydrogen peroxide to obtain hydroxylated fumed silica; the activation temperature is 70-80℃ and the time is 0.5-2h. In step S2, the mass ratio of the hydroxylated fumed silica to carboxymethyl cellulose is 1:(4-10); In step S2, the temperature of the heating ultrasonic reaction is 50-90℃, and the time is 2-6h.

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 additives are selected from one or more of leveling agents, defoamers, ultraviolet absorbers, dispersants, and antioxidants.

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 high-stability epoxy impregnated insulating varnish according to claim 1, characterized in that, The mass ratio of concentrated sulfuric acid to hydrogen peroxide is (60-80):(20-40).

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