Environment-friendly thermal stress resistant metal water-based paint as well as preparation method and application thereof

Abstract

The invention discloses environment-friendly thermal-stress-resistant metal water-based paint as well as a preparation method and application thereof, and belongs to the technical field of material corrosion prevention. The environment-friendly thermal stress resistant metal water-based paint is prepared from the following components in percentage by mass: 2 to 3 percent of zinc oxide, 4 to 5 percent of zinc phosphate, 8 to 10 percent of ferric oxide, 7 to 9 percent of titanium dioxide, 40 to 45 percent of styrene-acrylic emulsion, 4 to 5 percent of sodium silicate, 4 to 5 percent of glass fiber, 0.1 to 0.4 percent of polydimethylsiloxane, 0.1 to 0.4 percent of triethanolamine and 20 to 25 percent of water. The novel metal water-based paint is designed by combining the characteristics of emulsion type water-based paint and inorganic water-based paint, not only can be tightly adhered to the metal surface to form a tough protective film, prevent corrosion medium permeation and prolong the service life of a metal component, but also can keep good mechanical property and chemical stability in a high-temperature environment, and has a good application prospect. And stress cracks and peeling caused by temperature change are effectively resisted, and the metal surface is protected from thermal damage.

Description

Technical Field

[0001] The present invention belongs to the technical field of material anti-corrosion, and particularly relates to an environment-friendly heat stress-resistant metal water-based paint, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of technology, water-based paint products are becoming more and more suitable for market use in terms of product performance. They have been recognized by the market in many fields. The water-based raw material technology and formulation technology are gradually improving, and there are more and more varieties of water-based coatings. Some of their performances have gradually caught up with and even surpassed solvent-based products. Among them, water-based architectural decorative coatings (latex paints), water-based wood coatings, water-based metal coatings, water-based glass coatings, water-based plastic coatings, water-based anti-corrosion coatings, water-based automotive coatings, etc. are all booming.

[0003] One-component water-based polyurethane paint is one of the earliest applied water-based polyurethane paints. It occupies a place in the coating industry by virtue of its environmental protection characteristics and excellent physical properties. One-component water-based polyurethane paint is a kind of paint with water as the solvent. It does not need to add additional curing agents, is easy to use, and reduces the construction difficulty and cost. This kind of paint has good flexibility and elasticity, can adapt to the deformation of the substrate to a certain extent, and reduces the risk of cracking. One-component water-based polyurethane paint is famous for its high elongation at break and appropriate strength, and can dry quickly at room temperature, which makes it more convenient and efficient in the construction process. However, one-component water-based polyurethane paint is slightly insufficient in terms of chemical resistance and solvent resistance, and its hardness, surface gloss and vividness are also relatively low.

[0004] In order to overcome the above limitations, scientific research personnel have developed a new type of water-based paint - emulsion-type and inorganic soluble silicate characteristic water-based paint. This water-based paint combines the resin of emulsion-type paint as the base, and uses soluble silicate, inorganic salts, metal oxides, silica powder, etc. as fillers and additives, greatly improving the comprehensive performance of the paint film. In addition, a prominent feature of this water-based paint is its extremely fast curing speed, which can form a stable paint film in a short time, greatly shortening the construction period. In addition, due to the use of water as the dispersion medium, the VOC emissions of this paint are extremely low, which is friendly to the human body and the environment and meets the requirements of environmental protection in modern society.

[0005] Considering these remarkable advantages, emulsion-type and inorganic soluble silicate characteristic waterborne paints have extremely broad market prospects. They can not only meet the painting requirements of multiple industries such as construction, automotive, shipbuilding, and machinery manufacturing, but also find applications in high-tech fields such as new energy and aerospace, for example, in the field of improving the thermal stress resistance of metals. Metals having thermal stress resistance can ensure the structural integrity and performance stability of metal materials in high-temperature or temperature-changing environments. Structural components working in high-temperature environments, such as engine parts, heat exchangers, and turbine blades, must have sufficient thermal stress resistance to prevent cracks and failures caused by thermal stress due to temperature changes. Metal materials with good thermal stress resistance can reduce early failures caused by thermal fatigue, thereby extending the service life of metal components. In addition, in energy production, improving the thermal stress resistance of metal materials helps to improve thermal efficiency. For example, increasing the operating temperature of turbines can improve power generation efficiency, while reducing faults and damages caused by thermal stress and lowering the costs of maintenance and component replacement.

[0006] Chinese Patent with Publication No. CN103289455A and Application Date of July 8, 2013 discloses a formaldehyde-free and VOC-free inorganic functional coating and its preparation method. The inorganic functional coating is compounded with inorganic materials of different particle sizes, greatly enhancing the crosslinking density and increasing the density of the coating. At the same time, the raw materials of different particle sizes are mixed, filling the gaps between large-particle raw materials. The small-particle raw materials absorb and buffer the thermal stress dispersion between large particles, while the large-particle raw materials resist and isolate the thermal stress concentration of small-particle raw materials. However, this invention cannot overcome the common problems of traditional inorganic functional coatings, such as relatively high requirements for the construction environment, limited color selection, and relatively poor storage stability. Chinese Patent with Publication No. CN103695827A and Application Date of January 6, 2014 provides a method for eliminating high-temperature quenching cracks in superalloy materials. First, the surface of the superalloy is subjected to sandblasting or shot peening treatment, and then a coating of a certain thickness is brushed or sprayed. The coating composition contains an inorganic polymer and metal oxide powder. The mixing ratio of the coating to water is 1:1 - 1:2. After brushing or spraying, a film of a certain thickness is formed on the surface of the superalloy workpiece. The film bears the maximum thermal stress on the surface of the superalloy during quenching and falls off, reducing the thermal stress on the surface of the workpiece during quenching and eliminating the cracking problem. However, the technical effect of overcoming thermal stress will disappear after the film falls off, and there is a technical problem of cleaning the fallen film.

[0007] Metallic materials with the ability to resist thermal stress are crucial for ensuring the safety and reliability of industrial products in high-temperature or temperature-changing environments. Therefore, by adopting appropriate design and material selection strategies, and combining the characteristics of emulsion-based waterborne paints and inorganic waterborne coatings to design a new type of metallic waterborne paint, thereby improving the thermal stress resistance of metallic materials, extending their service life and reducing maintenance costs, it is of great significance to meet the growing demand for thermal stress-resistant metallic materials. Summary of the Invention

[0008] To solve the problems existing in the prior art, the present invention provides an environmentally friendly thermal stress-resistant metallic waterborne paint, its preparation method and application. It can not only adhere tightly to the metal surface to form a tough protective film, prevent the penetration of corrosive media, and extend the service life of metal components, but also maintain good mechanical properties and chemical stability in high-temperature environments, effectively resist stress cracks and peeling caused by temperature changes, and protect the metal surface from heat damage.

[0009] The technical solution of the present invention is as follows:

[0010] One of the purposes of the present invention is to provide an environmentally friendly thermal stress-resistant metallic waterborne paint, and the metallic waterborne paint comprises the following components in mass percentage: zinc oxide 2-3%, zinc phosphate 4-5%, iron(III) oxide 8-10%, titanium dioxide 7-9%, styrene-acrylic emulsion 40-45%, sodium silicate 4-5%, glass fiber 4-5%, polydimethylsiloxane 0.1-0.4%, triethanolamine 0.1-0.4%, water 20-25%.

[0011] Further, the metallic waterborne paint comprises the following components in mass percentage: zinc oxide 2%, zinc phosphate 4%, iron(III) oxide 8%, titanium dioxide 8%, styrene-acrylic emulsion 45%, sodium silicate 4%, glass fiber 4%, polydimethylsiloxane 0.2%, triethanolamine 0.2%, water 24.6%.

[0012] Further, the solid content of the styrene-acrylic emulsion is 46±1%, the viscosity is 400-1500 mPa·S, the pH value is 7.0-9.0, the monomer residue is 0.5%, and the lower limit of the film-forming temperature is 24°C.

[0013] Further, the density of the glass fiber is 2.54 g / cm 3 , the tensile stress is 2000 MPa, the flexural stress is 200 MPa, the shrinkage rate is 0.9%, and the Rockwell hardness is HRC70.

[0014] Another purpose of the present invention is to provide a preparation method of an environmentally friendly thermal stress-resistant metallic waterborne paint, comprising the following steps:

[0015] (1) Measure deionized water as required, weigh zinc oxide, zinc phosphate, glass fiber, iron(III) oxide, titanium dioxide and sodium silicate, and add them to the paint mixing tank in sequence. After fully stirring, add polydimethylsiloxane, and after stirring evenly, grind at high speed in a grinder for 60 - 70 min;

[0016] (2) Add styrene-acrylic emulsion and the mixed raw materials ground evenly in step (1) to the paint mixing tank, regulate the pH value with triethanolamine, and after mixing evenly, continue to grind in a sand mill for 20 - 30 min;

[0017] (3) Filter the ground mixed raw materials with a wire mesh and package them to obtain the environmentally friendly heat-resistant stress metal waterborne paint.

[0018] Further, in step (2), the pH value is 8 - 9, and grind until the fineness reaches 20 - 30 μm.

[0019] Further, in step (3), grind until the fineness reaches 20 - 30 μm, and the wire mesh is 100 - 150 mesh.

[0020] The third object of the present invention is to provide an application of the environmentally friendly heat-resistant stress metal waterborne paint in improving the heat-resistant stress of phosphated iron sheets.

[0021] Further, evenly apply the metal waterborne paint on the phosphated iron sheet, dry it at 60 °C, then bake it at 180 - 200 °C for 3 min, and then quickly cool the temperature to room temperature with cold water to obtain a paint film with improved heat-resistant stress.

[0022] Further, the thickness of the paint film is 20 - 30 μm.

[0023] Further, the adhesion of the paint film is grade 1.

[0024] Further, the pencil hardness of the paint film is 8H.

[0025] Further, after the paint film is subjected to heat aging treatment at 80 °C for 24 h, the paint film does not blister, delaminate, wrinkle or crack.

[0026] Further, after the paint film is subjected to salt spray corrosion in 0.1 mol / L acidic iron nitrate solution for 24 h, no blistering, wrinkling or paint film peeling and other phenomena occur.

[0027] Further, paint films are prepared by coating the metal waterborne paint on iron wires with diameters of 1.0 mm and 2.0 mm respectively. After folding in half 3 times, no wrinkles, reticulations, cracks or even paint film peeling and other phenomena occur near the folding points.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] 1. The present invention designs a new type of metal waterborne paint by combining the characteristics of emulsion-type waterborne paint and inorganic waterborne coating. The metal waterborne paint can not only adhere tightly to the metal surface to form a tough protective film, prevent the penetration of corrosive media, and extend the service life of metal components, but also maintain good mechanical properties and chemical stability in high-temperature environments, effectively resist stress cracks and peeling caused by temperature changes, protect the metal surface from heat damage. In addition, the metal waterborne paint uses water as a dispersion medium, greatly reducing the emission of volatile organic compounds (VOCs), and is friendly to the environment and organisms.

[0030] 2. The present invention first discloses a metal waterborne paint composed of zinc oxide, zinc phosphate, iron(III) oxide, titanium dioxide, styrene-acrylic emulsion, sodium silicate, glass fiber, polydimethylsiloxane, triethanolamine and water, and proposes a preferred component ratio. Among them, due to the characteristics of polydimethylsiloxane such as low surface tension, easy spreading, and appropriate viscosity, it can improve the lubricity, anti-adhesion and uniformity of the paint film. On this basis, the phosphate ions of zinc phosphate react with metal iron ions to form a stable complex, forming a dense water-insoluble composite protective film on the metal surface, promoting the passivation of the metal surface, and having good rust prevention effect and mechanical strength, which helps to prevent mechanical damage; at the same time, the ultraviolet light shielding ability of zinc oxide can protect zinc phosphate and the coating from ultraviolet damage. By combining the weather resistance of zinc phosphate and the ultraviolet light shielding effect of zinc oxide, the overall weather resistance of the coating can be improved.

[0031] 3. The metal waterborne paint of the present invention adds styrene-acrylic emulsion, sodium silicate, glass fiber to its composition, and uses triethanolamine to adjust the pH value. The styrene-acrylic emulsion can combine with the continuous film formed by iron(III) oxide and titanium dioxide, making the paint film have good adhesion and aging resistance. At the same time, the combination of the film-forming performance of the styrene-acrylic emulsion and the bonding performance of sodium silicate further enhances the dispersion stability and adhesion of each component in the paint. Triethanolamine neutralizes the acidic substances in the paint to form salt crystals, improving the adhesion between the paint film and the substrate, ensuring that the paint film can adhere evenly and tightly to the metal substrate, thereby blocking the penetration of corrosive media into the interior of the coating, reducing the erosion of salts and moisture on the metal substrate, and effectively improving the strength and salt spray corrosion resistance of the paint. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the appearance structure diagram of the environmentally friendly heat stress-resistant metal waterborne paint described in the present invention;

[0033] Figure 2 It is the comparison diagram of the heat aging resistance test of the environmentally friendly heat stress-resistant metal waterborne paint described in the performance test of the present invention;

[0034] Figure 3This is a comparison chart of the adhesion test of the environmentally friendly heat stress resistant metal water-based paint film described in the performance test of the present invention;

[0035] Figure 4 This is a comparison chart of the salt spray corrosion resistance test of the environmentally friendly heat stress resistant metal water-based paint described in the performance test of the present invention;

[0036] Figure 5 This is a sample diagram of pencil hardness test of environmentally friendly heat stress resistant metal water-based paint described in the performance test of the present invention;

[0037] Figure 6 This is a diagram of the flexibility test sample of the environmentally friendly heat stress resistant metallic water-based paint described in the performance test of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with preferred embodiments. The endpoints of the ranges disclosed in the present invention and any values ​​are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be deemed to be specifically disclosed herein.

[0039] The experimental methods in the following examples, unless otherwise specified, are conventional methods and are performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0040] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0041] Example 1

[0042] This embodiment provides an environmentally friendly thermal stress-resistant metallic water-based paint, and the preparation method thereof is as follows:

[0043] S1. Prepare metallic water-based paint according to the following ingredients: 2% zinc oxide, 4% zinc phosphate, 8% ferric oxide, 8% titanium dioxide, 45% styrene acrylic emulsion, 4% sodium silicate, 4% glass fiber, 0.2% polydimethylsiloxane, 0.2% triethanolamine, and 24.6% water;

[0044] S2, add deionized water, zinc oxide, zinc phosphate, glass fiber, ferric oxide, titanium dioxide and sodium silicate to the paint mixing tank in sequence, stir thoroughly and then add polydimethylsiloxane, stir evenly and grind at high speed in a grinder for 60 minutes;

[0045] S3, adding styrene acrylic emulsion and the mixed raw materials ground evenly in step (1) into a paint mixing tank, adjusting the pH value to 8 with triethanolamine, and continuing to grind in a sand mill for 20 minutes until the fineness reaches 20 μm after mixing evenly;

[0046] S4, filtering the ground and mixed raw materials with a 100-mesh gauze and packaging them to obtain the environmentally friendly heat-resistant metal water-based paint.

[0047] S5. Apply the metallic water-based paint on a 50 mm × 25 mm × 2 mm iron phosphide sheet, dry it at 60 ° C, and then bake it at 180 ° C for 3 minutes;

[0048] S6. Use cold water to suddenly reduce the temperature to room temperature to obtain an environmentally friendly, heat-resistant, and stress-resistant metallic water-based paint film with a thickness of 20 μm.

[0049] The environmentally friendly heat stress resistant metallic water-based paint film prepared in this embodiment has uniform color and texture and a smooth surface.

[0050] Example 2

[0051] This embodiment provides an environmentally friendly thermal stress-resistant metallic water-based paint, and the preparation method thereof is as follows:

[0052] S1. Prepare metallic water-based paint according to the following ingredients: 3% zinc oxide, 5% zinc phosphate, 9% ferric oxide, 7% titanium dioxide, 41.5% styrene acrylic emulsion, 5% sodium silicate, 5% glass fiber, 0.1% polydimethylsiloxane, 0.4% triethanolamine, and 24% water;

[0053] S2. Add deionized water, zinc oxide, zinc phosphate, glass fiber, ferric oxide, titanium dioxide and sodium silicate to the paint mixing tank in sequence, stir thoroughly and then add polydimethylsiloxane, stir evenly and grind at high speed in a grinder for 65 minutes;

[0054] S3, adding styrene acrylic emulsion and the mixed raw materials ground evenly in step (1) into a paint mixing tank, adjusting the pH value to 8.5 with triethanolamine, and continuing to grind in a sand mill for 25 minutes until the fineness reaches 25 μm after mixing evenly;

[0055] S4, filtering the ground and mixed raw materials with a 130-mesh gauze and packaging them to obtain the environmentally friendly heat-resistant metal water-based paint.

[0056] S5. Apply the metallic water-based paint on a 50 mm × 25 mm × 2 mm iron phosphide sheet, dry it at 60 ° C, and bake it at 190 ° C for 3 minutes;

[0057] S6. Use cold water to suddenly drop the temperature to room temperature to obtain an environmentally friendly, heat-resistant, and stress-resistant metallic water-based paint film with a thickness of 26 μm.

[0058] Example 3

[0059] This embodiment provides an environment-friendly heat-resistant stress metal water-based paint, and its preparation method is as follows:

[0060] S1. Configure the metal water-based paint according to the following components: zinc oxide 3%, zinc phosphate 5%, iron(III) oxide 10%, titanium dioxide 9%, styrene-acrylic emulsion 40%, sodium silicate 5%, glass fiber 5%, polydimethylsiloxane 0.4%, triethanolamine 0.1%, water 22.5%;

[0061] S2. Add deionized water, zinc oxide, zinc phosphate, glass fiber, iron(III) oxide, titanium dioxide and sodium silicate into the paint mixing tank in sequence. After fully stirring, add polydimethylsiloxane, and then stir evenly and grind at high speed in a grinder for 70 min;

[0062] S3. Add styrene-acrylic emulsion and the mixed raw materials ground evenly in step (1) into the paint mixing tank, adjust the pH value to 9 with triethanolamine, and continue to grind in a sand mill for 30 min until the fineness reaches 30 μm after mixing evenly;

[0063] S4. Filter the ground mixed raw materials with a 150-mesh screen and package them to obtain the environment-friendly heat-resistant stress metal water-based paint.

[0064] S5. Apply the metal water-based paint on a phosphated iron sheet of 50 mm × 25 mm × 2 mm, dry it at 60 °C, and then bake it at 200 °C for 3 min;

[0065] S6. Use cold water to rapidly cool the temperature to room temperature to obtain an environment-friendly heat-resistant stress metal water-based paint film with a thickness of 30 μm.

[0066] Performance Test

[0067] 1. Heat-resistant aging test

[0068] Suspend the environment-friendly heat-resistant stress metal water-based paint film prepared in Example 1 of the present invention with copper wire in a heat aging test chamber for heat-resistant aging test, set the temperature to 80 °C, and the time to 24 h.

[0069] The test results are as Figure 2 shown, and no fading, blistering, wrinkling, cracking or film peeling phenomenon occurs on the paint film.

[0070] 2. Paint film adhesion test

[0071] Place the environment-friendly heat-resistant stress metal water-based paint film prepared in Example 1 of the present invention at 80 °C for heat aging treatment for 24 h, and conduct paint film adhesion test.

[0072] The test results are as Figure 3As shown, no blistering, delamination, wrinkling or cracking occurred in the paint film, and its heat aging resistance was excellent.

[0073] 3. Salt spray corrosion resistance test

[0074] The paint film of the environment-friendly heat-resistant stress metal waterborne paint prepared in Example 1 of the present invention was subjected to salt spray corrosion with a 0.1 mol / L acidic ferric nitrate solution for 24 h for the salt spray corrosion resistance test.

[0075] The test results are as Figure 4 shown. No blistering, wrinkling or paint film peeling occurred in the paint film, and its salt spray corrosion resistance was excellent.

[0076] 4. Pencil hardness test

[0077] Pencils with different hardnesses were used to scratch the upper surface of the paint film of the environment-friendly heat-resistant stress metal waterborne paint prepared in Example 1 of the present invention, and the damage condition of the coating was observed to determine its hardness grade.

[0078] The test results are as Figure 5 shown. The pencil hardness of the paint film was 8H, indicating a high hardness.

[0079] 5. Flexibility test

[0080] According to the method described in Example 1 of the present invention, an environment-friendly heat-resistant stress metal waterborne paint was prepared. The metal waterborne paint was respectively coated on iron wires with diameters of 1.0 mm and 2.0 mm to obtain paint films, and then the iron wires were folded in half three times and the folding points were observed.

[0081] The test results are as Figure 6 shown. No wrinkles, reticulations, cracks or even paint film peeling occurred in the paint films near the folding points of the iron wires, indicating good flexibility of the paint films.

[0082] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. An environmentally friendly thermal stress resistant metallic water-based paint, characterized in that: The metallic water-based paint comprises the following components in percentage by weight: 2-3% zinc oxide, 4-5% zinc phosphate, 8-10% ferric oxide, 7-9% titanium dioxide, 40-45% styrene acrylic emulsion, 4-5% sodium silicate, 4-5% glass fiber, 0.1-0.4% polydimethylsiloxane, 0.1-0.4% triethanolamine and 20-25% water.

2. The environmentally friendly heat stress resistant metallic water-based paint according to claim 1, characterized in that: The metallic water-based paint comprises the following components in percentage by weight: 2% zinc oxide, 4% zinc phosphate, 8% ferric oxide, 8% titanium dioxide, 45% styrene acrylic emulsion, 4% sodium silicate, 4% glass fiber, 0.2% polydimethylsiloxane, 0.2% triethanolamine and 24.6% water.

3. The environmentally friendly heat stress resistant metallic water-based paint according to claim 1, characterized in that: The styrene-acrylic emulsion has a solid content of 46±1%, a viscosity of 400-1500 mPa·S, a pH value of 7.0-9.0, a monomer residue of 0.5%, and a lower limit of a film-forming temperature of 24°C.

4. The environmentally friendly heat stress resistant metallic water-based paint according to claim 1, characterized in that: The glass fiber density is 2.54 g / cm 3 , tensile stress is 2000MPa, bending stress is 200MPa, shrinkage rate is 0.9%, and Rockwell hardness is HRC70.

5. A method for preparing the environmentally friendly anti-thermal stress metallic water-based paint as claimed in any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Take deionized water as required, weigh zinc oxide, zinc phosphate, glass fiber, ferric oxide, titanium dioxide and sodium silicate and add them to the paint mixing tank in sequence, stir thoroughly and then add polydimethylsiloxane, stir evenly and grind at high speed in a grinder for 60-70 minutes; (2) adding styrene acrylic emulsion and the mixed raw materials ground uniformly in step (1) into a paint mixing tank, adjusting the pH value with triethanolamine, and continuing to grind in a sand mill for 20-30 minutes after mixing uniformly; (3) filtering the ground mixed raw materials with a gauze and packaging them to obtain the environmentally friendly heat-resistant metal water-based paint.

6. The method for preparing an environmentally friendly heat stress resistant metallic water-based paint according to claim 5, characterized in that: In the step (2), the pH value is 8-9, and the powder is ground to a fineness of 20-30 μm.

7. The method for preparing an environmentally friendly heat stress resistant metallic water-based paint according to claim 5, characterized in that: In the step (3), the gauze mesh is 100-150 meshes.

8. Use of the environmentally friendly anti-thermal stress metallic water-based paint as claimed in any one of claims 1 to 4 in improving the thermal stress resistance of iron phosphide sheets.

9. The use of an environmentally friendly heat stress resistant metallic water-based paint according to claim 8, characterized in that: The metallic water-based paint is evenly applied on the iron phosphide sheet, dried at 60°C, baked at 180-200°C for 3 minutes, and then cooled to room temperature with cold water to obtain a paint film with improved thermal stress resistance.

10. The use of an environmentally friendly anti-thermal stress metallic water-based paint according to claim 8, characterized in that: The paint film thickness is 20-30 μm.

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