Fingerprint-resistant treating agent for back paint of color-coated sheet and preparation method of fingerprint-resistant treating agent

Abstract

The invention discloses a fingerprint-resistant treating agent for back paint of a color-coated sheet. The fingerprint-resistant treating agent comprises the following raw materials in percentage by mass: 3-5% of a chelating zirconium-titanium compound, 1-2% of a silane coupling agent, 15-25% of thermosetting acrylic resin, 1-2% of water-based wax and the balance of water. The invention further discloses a preparation method of the fingerprint-resistant treating agent, and the problems that an existing color-coated plate back paint treating agent is poor in adhesive force, and the protective performance of a plate is affected are solved. The fingerprint-resistant treating agent disclosed by the invention is high in adhesive force and can be tightly attached to polystyrene foam, so that the protection performance of the color-coated sheet is improved, and the service life of the color-coated sheet is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of anti-fingerprint treating agents, in particular to an anti-fingerprint treating agent for back paint of color-coated plates. Background Art

[0002] PCM panels are widely used in industry and daily life, including automobiles, refrigerators, washing machines, and industrial and residential buildings. Most existing PCM panels require a protective and decorative coating before they can be used as a full-scale product. The backcoat of PCM steel sheets for common home appliances is a polyester oil-based paint, with a thickness of 5-8μm after application and curing. For use in the home appliance industry, after stamping the metal sheet, the back is typically coated with a fingerprint-resistant treatment agent, then glued with foam glue and then filled with plastic sheeting.

[0003] However, the existing back-paint treatment method for color-coated boards requires the steps of passivation agent-paint primer-paint topcoat, and performs poorly in terms of adhesion between the treatment agent and the substrate and the back-paint. Especially in some scenarios where high performance of the board is required, such as the manufacture of home appliance housings, the board needs to withstand various complex environmental factors, such as temperature changes, humidity fluctuations, mechanical stress, etc. Due to insufficient adhesion, the back-paint is prone to peeling and other phenomena, which not only seriously affects the appearance quality of the color-coated board and makes it lose its original aesthetics, but also reduces the protective performance of the board, causing the substrate to be exposed, accelerating corrosion and aging, shortening the service life of the color-coated board, and increasing the cost of subsequent maintenance and replacement. In addition, some existing treatment agents may contain harmful substances, such as heavy metals, volatile organic compounds, etc. These substances may cause potential harm to the environment and human health during production and use. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing color-coated plate back paint treatment agent has poor adhesion, which affects the protective performance of the plate. The purpose is to provide an anti-fingerprint treatment agent for color-coated plate back paint and a preparation method.

[0005] The present invention is achieved through the following technical solutions: The invention discloses an anti-fingerprint treating agent for the back paint of color-coated plates, which comprises, by mass percentage, 3-5% of a chelated zirconium-titanium compound, 1-2% of a silane coupling agent, 15-25% of a thermosetting acrylic resin, 1-2% of a water-based wax, and the balance being water.

[0006] As one of the preferred technical solutions, the chelated zirconium-titanium compound is a citrate zirconium-titanium compound.

[0007] As one of the preferred technical solutions, the silane coupling agent is epoxy silane.

[0008] As one of the preferred technical solutions, the thermosetting acrylic resin is an epoxy acrylic resin.

[0009] As one of the preferred technical solutions, the water-based wax is water-based acrylic wax.

[0010] In a second aspect, the present invention further provides a preparation method, characterized in that it comprises the following steps: Add pure water to tank A, then add acetic acid to adjust the pH value; Then, slowly add epoxy silane into tank A while stirring until it is completely dissolved and set aside to obtain liquid A; Add pure water to tank B, then slowly add the titanium zirconium citrate compound while stirring until it is completely dissolved; In tank B, slowly add the epoxy acrylic resin while stirring again until it is completely dissolved; In tank B, slowly add the water-washable acrylic wax while stirring until it is completely dissolved to obtain liquid B. Slowly add liquid A into tank B and mix with liquid B, stirring until completely dissolved; Finally, add the remaining pure water into tank B and stir to obtain the finished product.

[0011] As one of the preferred technical solutions, the adjusted pH value is 3.0.

[0012] As one of the preferred technical solutions, when the remaining pure water is finally added, the pure water can be washed in tank A and then completely poured into tank B.

[0013] As one of the preferred technical solutions, the remaining pure water is finally added to tank B and stirred for 20 minutes to obtain the finished product.

[0014] In a third aspect, the anti-fingerprint treating agent of the present invention is used in the back paint of PCM steel plates for household appliances.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The anti-fingerprint treatment agent of the present invention has strong adhesion and can achieve close adhesion with the foam glue, thereby improving the protective performance of the color-coated plate and extending the service life of the color-coated plate.

[0016] 2. In the existing process, the back paint needs to go through the passivation agent-paint primer-paint topcoat when applying the back paint, while the present invention only needs to apply the anti-fingerprint treatment agent instead of the existing three steps. The process flow is simpler, and the investment cost is reduced while ensuring high performance.

[0017] 3. The anti-fingerprint treatment agent of the present invention is green and environmentally friendly and does not contain toxic heavy metal components.

[0018] 4. The anti-fingerprint treating agent of the present invention also has the property of high temperature resistance, thereby ensuring that it can adapt to multiple environments during the process steps. DETAILED DESCRIPTION

[0019] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0020] Example 1 This embodiment 1 provides an anti-fingerprint treatment agent for color-coated plate back paint, which includes the following raw materials in percentage by mass: Epoxy silane 3%, citrate complex chelating agent 5%, epoxy acrylic resin 20% and water-based acrylic wax 2%.

[0021] The preparation method comprises the following steps: Add 10 kg of pure water to tank A, then add acetic acid to adjust the pH to 3.0; Then slowly add 3 kg of epoxy silane into tank A and stir until completely dissolved to obtain liquid A; Add 50 kg of pure water to tank B and slowly add 5 kg of citrate zirconium titanium compound while stirring until it is completely dissolved; In tank B, slowly add 20 kg of epoxy acrylic resin again while stirring until it is completely dissolved; In tank B, slowly add 2 kg of water-washed acrylic wax while stirring until it is completely dissolved to obtain liquid B. Slowly add liquid A into tank B and mix with liquid B, stirring until completely dissolved; Finally, add the remaining pure water into tank B and stir for 20 minutes to obtain the finished product.

[0022] In the above process, tank A and tank B are two different liquid mixing tanks, which have corrosion resistance and high temperature resistance, and are equipped with stirring devices to ensure that the reagents can be fully mixed evenly.

[0023] Example 2 This embodiment 1 provides an anti-fingerprint treatment agent for the back paint of a color-coated plate, which includes the following raw materials in percentage by mass: 1% epoxy silane, 3% citrate composite chelating agent, 25% epoxy acrylic resin and 1% water-based acrylic wax.

[0024] The preparation method comprises the following steps: Add 10 kg of pure water to tank A, then add acetic acid to adjust the pH to 2.8; Then slowly add 1 kg of epoxy silane into tank A and stir until completely dissolved to obtain liquid A; Add 40 kg of pure water to tank B and slowly add 3 kg of titanium zirconium citrate compound while stirring until it is completely dissolved; In tank B, slowly add 25 kg of epoxy acrylic resin again while stirring until it is completely dissolved; In tank B, slowly add 1 kg of water-washed acrylic wax while stirring until it is completely dissolved to obtain liquid B. Slowly add liquid A into tank B and mix with liquid B, stirring until completely dissolved; Finally, add the remaining pure water into tank B and stir for 25 minutes to obtain the finished product.

[0025] In the above process, tank A and tank B are two different liquid mixing tanks, which have corrosion resistance and high temperature resistance, and are equipped with stirring devices to ensure that the reagents can be fully mixed evenly.

[0026] Example 3 This embodiment 1 provides an anti-fingerprint treatment agent for the back paint of a color-coated plate, which includes, by mass percentage, 2% epoxy silane, 4% citrate composite chelating agent, 15% epoxy acrylic resin, and 1.5% water-based acrylic wax.

[0027] The preparation method comprises the following steps: Add 10 kg of pure water to tank A, then add acetic acid to adjust the pH to 3.5; Then slowly add 2 kg of epoxy silane into tank A and stir until completely dissolved to obtain liquid A; Add 50 kg of pure water to tank B and slowly add 4 kg of titanium zirconium citrate compound while stirring until it is completely dissolved; In tank B, slowly add 15 kg of epoxy acrylic resin again while stirring until it is completely dissolved; In tank B, slowly add 1.5 kg of water-washed acrylic wax while stirring until it is completely dissolved to obtain liquid B. Slowly add liquid A into tank B and mix with liquid B, stirring until completely dissolved; Finally, add the remaining pure water into tank B and stir for 17 minutes to obtain the finished product.

[0028] In the above process, tank A and tank B are two different liquid mixing tanks, which have corrosion resistance and high temperature resistance, and are equipped with stirring devices to ensure that the reagents can be fully mixed evenly.

[0029] Example 4 Confirmation of the components of the treatment agent Currently, the back paint of PCM steel plates used in ordinary household appliances mostly adopts polyester oil-based paint, which is adhered to the PCM back plate by coating and curing, with a thickness in the range of 5-8μm.

[0030] However, the production of polyester oil-based paint requires multiple steps, including raw material mixing, reactor reaction, filtration, and paint adjustment. During the production and use of oil-based paint, harmful substances such as volatile organic compounds (VOCs) are produced, which harm the environment and human health. Companies need to invest in the construction of waste gas treatment systems, wastewater treatment facilities, etc., which increases environmental protection costs.

[0031] We have developed an environmentally friendly water-based polyurethane colorless coating to replace back paint. Under the same construction conditions, the thickness after curing is 0.8-1.2μm. At the same time, it meets the same stamping lubricity, corrosion resistance, expansion and contraction follow-up of the film under metal rheology, adhesion to foam glue and other coatings, and resistance to degreasing and phosphating as back paint, while the overall cost is less than 20% of that of ordinary back paint.

[0032] Experimental reagent: The zirconium-titanium compound components are selected as shown in Table 1 below: Table 1 Selection of zirconium and titanium compound components

[0033] The selection of silane coupling agent components is shown in Table 2: Table 2 Silane coupling agent composition selection

[0034] The selection of thermosetting acrylic resin components is shown in Table 3: Table 3 Selection of thermosetting acrylic resin components

[0035] The selection of water-based wax ingredients is shown in Table 4: Table 4 Water-based wax composition selection

[0036] The detection indicators are:

[0037] Among them, the flat plate salt spray test is an environmental test that uses salt spray test equipment to create artificial simulated salt spray environment conditions to evaluate the corrosion resistance of flat plate samples.

[0038] The cupping salt spray test is based on the cupping test and combines the salt spray test to test the salt spray corrosion resistance of the sample after the cupping test.

[0039] Adhesion testing examines coating peeling, cracking, or blistering. Good resistance to degreasing and phosphating is the foundation of a high-quality phosphate film. If the material is easily damaged during these two processes, defects in the phosphate film, such as an incomplete film layer and poor adhesion, can occur, affecting subsequent coating processes and reducing overall product quality.

[0040] Based on the above detection indicators: first, the water-insoluble silane coupling agent is hydrolyzed in advance; the specific preparation process is: add acetic acid to 100g of pure water and adjust the pH value to 3.0, and slowly add 10g of silane coupling agent while stirring until it is completely dissolved.

[0041] The zirconium-titanium compound was then added and stirred until completely dissolved. The above mixture accounted for approximately 30%, the zirconium-titanium compound accounted for approximately 5%, and the remainder was pure water. Since there were five types of silane coupling agents and four types of zirconium-titanium compounds, there were a total of 20 possible combinations. These 20 combinations were observed for 7 days, and the results are shown in Table 5.

[0042] Table 5 Dissolution of the combination of zirconium-titanium compounds and silane coupling agents

[0043] Conclusion: Among the 20 combinations mentioned above, 8 of them were completely dissolved or did not precipitate, that is, they were in a stable state.

[0044] Among them, the eight combinations are: citrate zirconium titanium compound + aminosilane, citrate zirconium titanium compound + mercaptosilane, citrate zirconium titanium compound + epoxysilane, citrate zirconium titanium compound + vinylsilane, citrate zirconium titanium compound + methacryloxysilane, alkoxy zirconium titanium compound + aminosilane, alkoxy zirconium titanium compound + vinylsilane and pyrophosphate zirconium titanium compound + epoxysilane.

[0045] The completely dissolved mixtures of the above eight combinations were then compounded with 20% of thermosetting acrylic resin (a total of four different components) to obtain 32 combination ratios; the stability was observed after standing for 7 days: the results are shown in Table 6.

[0046] Table 6 Dissolution of zirconium-titanium compound, silane coupling agent and thermosetting acrylic resin combination

[0047] Conclusion: Among the 32 combinations mentioned above, 8 of them were completely dissolved or did not precipitate, that is, they were in a stable state.

[0048] They are: citrate zirconium titanium compound + aminosilane + carboxyl acrylic resin, citrate zirconium titanium compound + aminosilane + epoxy acrylic resin, citrate zirconium titanium compound + epoxysilane + carboxyl acrylic resin, citrate zirconium titanium compound + epoxysilane + epoxy acrylic resin, citrate zirconium titanium compound + epoxysilane + amide acrylic resin, citrate zirconium titanium compound + vinylsilane + amide acrylic resin, citrate zirconium titanium compound + methacryloxysilane + epoxy acrylic resin and alkoxy zirconium titanium compound + aminosilane + carboxyl acrylic resin.

[0049] The eight selected combinations were then applied to a galvanized substrate without spangles. A scraper was used to verify the corrosion performance after 96 hours of flat salt spray and 48 hours of cupping salt spray. The corrosion area was less than 5%, meeting the standard. This is shown in Table 7.

[0050] Table 7 Detection performance comparison

[0051] Conclusion: Among the above 8 combination ratios, 4 of them meet the standards.

[0052] They are: citrate zirconium titanium compound + epoxy silane + carboxyl acrylic resin, citrate zirconium titanium compound + epoxy silane + epoxy acrylic resin, citrate zirconium titanium compound + epoxy silane + amide acrylic resin and citrate zirconium titanium compound + vinyl silane + amide acrylic resin.

[0053] Then, 2% of the water-based wax component was added to each of the four combinations that met the standards to obtain 12 combination ratios; the stability was confirmed, and the results are shown in Table 8.

[0054] Table 8 Comparison of stability performance

[0055] Conclusion: Five of the combinations were completely dissolved or did not precipitate, that is, they were in a stable state.

[0056] The five combined solutions obtained above were mixed with pure water in specific proportions to produce a uniform, milky white, opaque liquid treatment agent. A galvanized substrate without spangles was cut to the size of an A4 sheet of paper. A coating was applied using a #3 metal scraper at a curing temperature of 224°C to a thickness of 0.8-1.2 μm. The film properties were then evaluated, as shown in Table 9.

[0057] Table 9 Comparison of flat panel performance and smoke performance of 5 combination ratios

[0058] Conclusion: There are two combination ratios that meet all performance requirements, namely citrate zirconium titanium compound + epoxy silane + epoxy acrylic resin + water-based acrylic wax and citrate zirconium titanium compound + epoxy silane + amide acrylic resin + water-based acrylic wax.

[0059] Based on the existing knowledge, epoxy acrylic acid has a higher unit price but good stability, while amide acrylic acid has a lower unit price but poor stability. After comprehensive consideration, epoxy acrylic acid with better performance was finally selected.

[0060] Finally, the initial formulation is coated online and the panels are taken for verification.

[0061] The functions of each component in the present invention are: Pure water: conductivity is less than 20ppm to prevent calcium and magnesium ions from affecting product stability.

[0062] Epoxysilane compounds: They can act as a bridge between inorganic and organic materials, tightly combining the two through chemical bonding. This greatly improves the compatibility between inorganic and organic materials and enhances the overall performance of the composite material.

[0063] Citrate complex chelating agent: a new type of synthetic material, mainly used as a polymer cross-linking agent to improve the adhesion and smooth appearance of the coating.

[0064] Epoxy acrylic resin: A thermosetting resin that, after cross-linking and curing, creates a film with excellent water resistance, corrosion resistance, drug resistance, adhesion, and toughness. It is also the primary structural material in this formulation.

[0065] Water-based acrylic wax: A water-based wax emulsion that provides lubricity to the film layer, improves the scratch and wear resistance of the sheet, and also provides secondary adhesion.

[0066] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fingerprint-resistant treatment agent for color-coated plate back paint, characterized in that: The following raw materials are included in the proportion by mass: Chelated zirconium-titanium compound 3-5%, silane coupling agent 1-3%, thermosetting acrylic resin 15-25%, water-based wax 1-2%, and the balance is pure water.

2. The anti-fingerprint treating agent for color-coated plate back paint according to claim 1, characterized in that: The chelated zirconium-titanium compound is a citrate zirconium-titanium compound.

3. The anti-fingerprint treating agent for color-coated plate back paint according to claim 1, characterized in that: The silane coupling agent is epoxy silane.

4. The anti-fingerprint treating agent for color-coated plate back paint according to claim 1, characterized in that: The thermosetting acrylic resin is an epoxy acrylic resin or an amide acrylic resin.

5. The anti-fingerprint treating agent for color-coated plate back paint according to claim 1, characterized in that: The water-based wax is water-based acrylic wax.

6. A method for preparing an anti-fingerprint treatment agent for color-coated plate back paint, characterized in that: The steps include: Add pure water to tank A, then add acetic acid to adjust the pH value; Then, slowly add epoxy silane into tank A while stirring until it is completely dissolved and set aside to obtain liquid A; Add pure water to tank B, then slowly add the titanium zirconium citrate compound while stirring until it is completely dissolved; In tank B, slowly add the epoxy acrylic resin while stirring again until it is completely dissolved; In tank B, slowly add the water-washable acrylic wax while stirring until it is completely dissolved to obtain liquid B. Slowly add liquid A into tank B and mix with liquid B, stirring until completely dissolved; Finally, add the remaining pure water into tank B and stir to obtain the finished product.

7. The preparation method according to claim 6, characterized in that The pH value adjusted after adding acetic acid is 2.5-3.5, wherein the conductivity of pure water is less than 20ppm.

8. The preparation method according to claim 6, characterized in that When the remaining pure water is finally added, the pure water is cleaned in tank A and then completely poured into tank B.

9. The anti-fingerprint treating agent for color-coated plate back paint according to claim 6, characterized in that: Finally, add the remaining pure water into tank B and stir for 15-25 minutes to obtain the finished product.

10. Use of the anti-fingerprint treatment agent according to any one of claims 1 to 5 on PCM boards of household appliances.

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