Aqueous single-component high-temperature-resistant strippable coating and preparation method thereof

Abstract

The application discloses a water-based single-component high-temperature-resistant peelable coating and a preparation method thereof. The coating comprises 1-8 parts of silicate, 1-8 parts of silane coupling agent, 1-6 parts of ceramic powder, 1-6 parts of low-melting-point glass powder, 0.1-1 parts of silica sol and 0.1-0.5 parts of auxiliary agent in terms of weight fraction. The single-component inorganic coating has a higher use working temperature than general organic coatings, and through stress effect, the coating can be peeled off by itself, thereby providing temporary protection for the substrate at a higher temperature or providing favorable conditions for repairing the coating after the coating is damaged.

Description

Technical Field

[0001] This invention belongs to the field of inorganic coating technology, and particularly relates to a water-based single-component high-temperature resistant peelable coating and its preparation method. Background Technology

[0002] Thermal spraying technology is a method that uses a heat source to heat the coating material to a molten or semi-molten state, and then sprays it onto the surface of a pre-treated substrate at a certain speed to form a coating. Because the heat source temperature range is very wide, the coating materials that can be sprayed include almost all solid engineering materials, such as metals, alloys, ceramics, plastics, and composite materials composed of them. It can impart various functional surfaces to the substrate, such as wear resistance, corrosion resistance, high temperature resistance, oxidation resistance, insulation, heat insulation, biocompatibility, and infrared absorption.

[0003] In actual spraying processes, the substrate surface usually contains both surfaces requiring coating and surfaces that do not require coating. Surfaces that do not require coating need to be masked to prevent contamination by the coating material during spraying. The masking material is removed after spraying. Common methods include applying adhesive tape and applying peelable coatings. Adhesive tape and peelable coatings are typically made of organic polymers, which limits their high-temperature resistance. During thermal spraying, the masking material fails under high temperatures, resulting in peeling, burning, carbonization, and other contamination. Summary of the Invention

[0004] In view of this, the present invention discloses a water-based single-component high-temperature resistant peelable coating and its preparation method, so as to improve the high-temperature adaptability of thermal spraying substrates and improve thermal spraying efficiency.

[0005] The technical solution of the present invention is specifically a water-based single-component high-temperature resistant peelable coating, which, by weight, comprises 1-8 parts of silicate ester, 1-8 parts of silane coupling agent, 1-6 parts of ceramic powder, 1-6 parts of low-melting-point glass powder, 0.1-1 parts of silica sol, and 0.1-0.5 parts of additives.

[0006] Preferably, the silicate ester is one or a mixture of tetramethyl orthosilicate, tetraethyl orthosilicate, and silicon-40.

[0007] Preferably, the silane coupling agent is one or a mixture of several of methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane.

[0008] 4. The water-based single-component high-temperature resistant peelable coating according to claim 1, characterized in that the ceramic powder is one or a mixture of several of ceramic powder, alumina powder, zirconium oxide powder, and silicon oxide powder.

[0009] Preferably, the low-melting-point glass powder has a glass transition temperature of 300–600°C and a low coefficient of thermal expansion.

[0010] Preferably, the silica sol is an acidic silica sol with a pH value of 2 to 4.

[0011] Preferably, the additive is one or a mixture of sodium dodecyl sulfate, sodium tripolyphosphate, sodium pyrophosphate, and polyethylene glycol.

[0012] The present invention also provides a method for preparing the aforementioned water-based single-component high-temperature resistant peelable coating, comprising:

[0013] Step 1: Mix the silicate ester, silane coupling agent and silica sol thoroughly according to the weight proportions. Stir at a speed of 200-400 r / min for 30-60 min to obtain a mixed solution.

[0014] Step 2: According to the weight proportions, the ceramic powder, low melting point glass powder, additives and the mixed solution are mixed and dispersed evenly by ball milling at a speed of 30-80 r / min for 120-240 min to obtain the high temperature resistant peelable coating.

[0015] This invention provides a water-based, single-component, high-temperature resistant, peelable coating and its preparation method. The coating protects areas on a metal substrate that are prohibited from being sprayed during thermal spraying, preventing contamination by the thermally sprayed coating. After spraying, the coating can be peeled off automatically. It has advantages such as high temperature resistance, no pollution, and a simple coating preparation process, and can greatly solve the problem of shielding and protecting the substrate in high-temperature environments during metal thermal spraying.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the present invention. Detailed Implementation

[0017] Exemplary embodiments will now be described in detail. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of systems consistent with some aspects of the invention as detailed in the appended claims.

[0018] This implementation plan addresses the issue of masking and protecting metal substrates during selective thermal spraying. It proposes a high-temperature resistant, peelable coating, specifically a water-based, single-component, high-temperature resistant, peelable coating, with the following specific raw materials and formulation:

[0019] 1-8 parts silicate ester, 1-8 parts silane coupling agent, 1-6 parts ceramic powder, 1-6 parts low melting point glass powder, 0.1-1 part silica sol, and 0.1-0.5 parts additives.

[0020] The silicate ester is tetramethyl orthosilicate, tetraethyl orthosilicate, silicon-40, etc., including one or a mixture of several of them.

[0021] The silane coupling agent is methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane, etc., including one or a mixture of several of them.

[0022] The ceramic powder is ceramic powder, alumina powder, zirconia powder, silica powder, etc., including one or a mixture of several of them. The ceramic powder is a natural mineral ceramic powder, such as quartz powder, feldspar powder, etc.

[0023] The low-melting-point glass powder has a glass transition temperature of 300-600℃ and a low coefficient of expansion, wherein the low coefficient of expansion is less than 5*10^-6 / ℃; the silica sol is an acidic silica sol with a pH value of 2-4.

[0024] The additives are sodium dodecyl sulfate, sodium tripolyphosphate, sodium pyrophosphate, polyethylene glycol, etc., including one or a mixture of several of them.

[0025] A method for preparing a water-based, single-component, high-temperature resistant, peelable coating includes:

[0026] 1. According to the above-mentioned parts by weight, thoroughly mix the silicate ester, silane coupling agent, and silica sol at a stirring speed of 200-400 r / min for 30-60 min to obtain a mixed solution.

[0027] 2. According to the above-mentioned parts by weight, the ceramic powder, low-melting-point glass powder, additives, and mixture are ball-milled and dispersed evenly. The ball-milling speed is 30-80 r / min, and the time is 120-240 min to obtain a high-temperature resistant peelable coating.

[0028] 3. The prepared coating should be sealed and stored. When using it, apply it to the substrate surface as needed and allow it to dry and cure at room temperature.

[0029] This embodiment presents a water-based, single-component, high-temperature resistant, peelable coating. The coating uses a silicate ester and silane coupling agent, catalyzed by an acidic silica sol, to prepare a coating binder. This binder can adhere the encapsulated filler to the substrate surface, providing the coating with good adhesion at low temperatures. Furthermore, the three components—acid ester, silane coupling agent, and silica sol—have structures similar to the filler. The functional groups of these three components can react with the surface functional groups of the filler powder, allowing the mixed solution to better encapsulate the filler in the coating. The ceramic powder, acting as a high-temperature filler, provides protective properties for the coating at high temperatures. The acidic silica sol not only acts as a catalyst in the preparation of the binder but also in the coating curing stage, catalyzing the reaction between the coating and moisture in the air. Low-melting-point glass powder acts as a filler in the low-temperature stage of coatings, filling the interior of the coating. When the operating temperature exceeds its glass transition temperature, the glass powder softens and becomes sticky, providing adhesion for the coating at high temperatures. As the temperature drops, the glass powder cools, hardens, and becomes brittle. However, due to the significant difference between its coefficient of thermal expansion and that of the substrate, extreme stress is generated between the coating and the substrate, leading to delamination. Coating additives can ensure that the filler powder is fully and uniformly dispersed in the coating and improve the coating's application properties.

[0030] The coating of this invention utilizes the properties of low-temperature glass powder, acting as a filler at low temperatures and a binder at high temperatures. Upon cooling, it self-peels due to stress effects. It provides protection to the substrate at high temperatures and self-peels upon returning to room temperature, restoring the substrate to its original appearance. It is easy to use, water-based and environmentally friendly, self-peeling, and has significantly higher temperature resistance than other organic peelable coatings. It can greatly solve the problem of substrate shielding and protection in high-temperature environments during metal thermal spraying. It improves the high-temperature adaptability of thermal spraying substrates and increases thermal spraying efficiency.

[0031] In this implementation plan, the role of glass powder is divided into three stages:

[0032] When the temperature is below the glass transition temperature, the glass powder is still solid and acts as a filler in the coating.

[0033] When the temperature reaches or exceeds the glass transition temperature, the glass melts, softens, and becomes viscous, changing from a filling function to a bonding function.

[0034] When the temperature changes from high to low, the glass solidifies, becoming hard and brittle. Due to the significant difference in their coefficients of thermal expansion, the glass experiences considerable stress. The brittle glass cannot withstand such stress, and under this stress, it breaks and flakes off.

[0035] Ceramic powder plays a filling role throughout the entire process;

[0036] The present invention will be further explained and described below with specific embodiments, but these are not intended to limit the scope of protection of the present invention.

[0037] Example 1

[0038] 1. Mix 1 part tetraethyl orthosilicate, 4 parts methyltrimethoxysilane, and 0.2 parts acidic silica sol by mass ratio, stirring thoroughly at 300 rpm for 40 minutes to obtain a mixed solution.

[0039] 2. Mix 2 parts alumina powder, 3 parts low-melting-point glass powder, 0.1 parts sodium dodecyl sulfate, 0.1 parts polyethylene glycol, and a mixture according to the following mass ratio. Ball mill the mixture at 40 r / min for 180 min to obtain a high-temperature resistant, peelable coating.

[0040] 3. Prepare the coating and store it in a sealed container. When using, apply it to the substrate surface as needed and allow it to dry and cure at room temperature.

[0041] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the claims.

Claims

1. A water-based, single-component, high-temperature resistant, peelable coating, characterized in that, The product comprises, by weight, 1-8 parts silicate ester, 1-8 parts silane coupling agent, 1-6 parts ceramic powder, 1-6 parts low melting point glass powder, 0.1-1 parts silica sol, and 0.1-0.5 parts additives; wherein the silica sol is an acidic silica sol with a pH value of 2-4. The low-melting-point glass powder has a glass transition temperature of 300-600℃ and a coefficient of thermal expansion of less than 5*10. -6 / ℃.

2. The water-based, single-component, high-temperature resistant, peelable coating according to claim 1, characterized in that, The silicate ester is one or a mixture of tetramethyl orthosilicate, tetraethyl orthosilicate, and silicon-40.

3. The water-based, single-component, high-temperature resistant, peelable coating according to claim 1, characterized in that, The silane coupling agent is one or a mixture of several of methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane.

4. The water-based, single-component, high-temperature resistant, peelable coating according to claim 1, characterized in that, The ceramic powder is one or a mixture of several of the following: alumina powder, zirconium oxide powder, and silicon oxide powder.

5. The water-based, single-component, high-temperature resistant, peelable coating according to claim 1, characterized in that, The additive is one or a mixture of sodium dodecyl sulfate, sodium tripolyphosphate, sodium pyrophosphate, and polyethylene glycol.

6. A method for preparing a water-based, single-component, high-temperature resistant, peelable coating as described in any one of claims 1-5, characterized in that, include: Step 1: Mix the silicate ester, silane coupling agent and silica sol thoroughly according to the weight proportions. Stir at a speed of 200~400 r / min for 30~60 min to obtain a mixed solution. Step 2: According to the weight proportions, the ceramic powder, low melting point glass powder, additives and the mixed solution are mixed and dispersed evenly by ball milling at a speed of 30~80 r / min for 120~240 min to obtain the high temperature resistant peelable coating.