Special chromium-free fingerprint-resistant coating with self-repairing function for high aluminum, zinc, aluminum and magnesium

Abstract

The invention relates to a special chromium-free fingerprint-resistant coating with a self-repairing function for high aluminum, zinc, aluminum and magnesium, which comprises epoxy silane, zirconium carbonate, a waterborne polyurethane dispersion, a photoinitiator TPO, waterborne UV-cured resin, triethanolamine, a coalescing agent isopropanol and deionized water, and is prepared by the following steps: cleaning a stirring kettle, adding the deionized water, controlling the temperature to be less than or equal to 35 DEG C, and uniformly stirring; triethanolamine and zirconium carbonate are added; through the synergistic effect of the epoxy silane, the zirconium carbonate and the waterborne polyurethane dispersion, the purpose of providing excellent protection performance under the extremely low dry film thickness can still be achieved, by introducing a light activation system of the photoinitiator TPO and the waterborne UV curing resin, the coating has the ultraviolet-triggered self-repairing function, microcracks and damage can be automatically repaired, and the coating has the good application prospect. The service life of the coating is prolonged, energy consumption and carbon emission are remarkably reduced, and the coating is not prone to cracking during processing deformation by controlling the molecular weight and the solid content of the waterborne polyurethane dispersion and optimizing the flexibility and the adhesive force of the coating.

Description

Technical Field

[0001] The invention relates to the technical field of chrome-free fingerprint-resistant coatings, in particular to a chrome-free fingerprint-resistant coating with a self-repairing function, which is specially used for high-aluminum-zinc-aluminum-magnesium coatings. Background Art

[0002] High-aluminum zinc-aluminum-magnesium (Zn-Al-Mg, 55% aluminum content) is a new type of steel coil coating material. Due to its excellent corrosion resistance, workability, and edge rust resistance, it is widely used in outdoor construction, solar panels, greenhouses, power transmission and distribution equipment, and other fields. However, high-aluminum zinc-aluminum-magnesium is prone to surface corrosion and aging due to long-term exposure to harsh outdoor conditions such as ultraviolet light, humidity, heat, and salt spray, necessitating a protective coating.

[0003] Currently, the industry generally uses non-Cr Thin Organic Coating (non-CrTOC) as a surface protective layer for high-aluminum, zinc, aluminum, and magnesium materials. The main problems with traditional non-Cr thin organic coatings include:

[0004] 1. High curing temperature: Traditional coatings need to be cured at a high temperature of 130-150°C (PMT temperature), which results in high energy consumption and carbon emissions on the production line, which is not in line with the development trend of green manufacturing.

[0005] 2. High film thickness requirements: The wet film thickness of traditional coatings is usually 7-10 microns, and the dry film thickness is 1.0-1.2 g / m 2 , which not only increases the coating consumption (1.0-1.5 kg / ton steel), but also increases the production cost.

[0006] 3. Performance limitations: Traditional coatings have limited corrosion resistance and aging resistance, especially in long-term hot and humid environments and salt spray environments, which are prone to rust and color difference problems, making it difficult to meet the use requirements of harsh outdoor environments.

[0007] To address these issues, existing technologies have attempted to improve performance by optimizing coating formulations or introducing novel resin materials. However, these efforts have failed to simultaneously achieve the goals of low-temperature curing, low film thickness, and high performance. Furthermore, traditional coatings lack self-healing properties, and their protective performance rapidly deteriorates once microcracks or damage develop in the coating.

[0008] Therefore, there is an urgent need to develop a new type of chromium-free fingerprint-resistant coating with self-repairing function specifically for high-aluminum-zinc-aluminum-magnesium to solve the above problems. Summary of the Invention

[0009] In response to the shortcomings of the existing technology, the present invention provides a chromium-free fingerprint-resistant coating with self-repairing function specifically for high-aluminum-zinc-aluminum-magnesium, which can achieve excellent corrosion resistance and aging resistance under low film thickness and low-temperature curing conditions, and at the same time has self-repairing function to extend the service life of the coating and reduce production costs.

[0010] To achieve the above object, the present invention provides the following technical solution: a chromium-free, fingerprint-resistant coating with self-repairing function specifically for high-aluminum, zinc, aluminum and magnesium, comprising the following components by weight percentage:

[0011] Epoxy silane 3-5%;

[0012] Zirconium carbonate 2-4%;

[0013] Waterborne polyurethane dispersion 45-55%;

[0014] Photoinitiator TPO 2-3%;

[0015] Water-based UV curing resin 8-12%;

[0016] Triethanolamine 4-6%;

[0017] Coal-forming aid isopropyl alcohol 4-6%;

[0018] Deionized water 7-22%.

[0019] Furthermore, in order to limit its solid content and molecular weight to ensure the film-forming property and mechanical properties of the coating, the solid content of the aqueous polyurethane dispersion is 30-40% and the molecular weight is 5000-10000.

[0020] Furthermore, in order to clarify its chemical structure and ultraviolet absorption characteristics and ensure that it can effectively trigger the self-repair reaction, the photoinitiator TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and its ultraviolet absorption wavelength is 300-400 nm.

[0021] Furthermore, in order to limit its functional groups and curing mode and ensure synergistic effect with the photoinitiator, the water-based UV curable resin is a water-based resin containing acrylate functional groups, and its curing mode is ultraviolet light-induced free radical polymerization.

[0022] Furthermore, in order to limit the dry film thickness and curing temperature and reflect the low temperature and low film thickness advantages of the present invention, the dry film thickness of the coating is 0.2-0.5 g / m² and the curing temperature is 50-80°C.

[0023] Furthermore, in order to clarify the repair mechanism of the coating, the coating has a light-activated self-repair function. Under ultraviolet irradiation, the photoinitiator TPO triggers the cross-linking reaction of the water-based UV-curable resin to repair micro-damage to the coating.

[0024] A method for preparing the chromium-free fingerprint-resistant coating comprises the following steps:

[0025] Step 1: Clean the stirring tank, add deionized water, and control the temperature to ≤35°C;

[0026] Step 2: Add triethanolamine and zirconium carbonate, stir for 1-2 hours, and control the temperature ≤35°C;

[0027] Step 3: Add epoxy silane, stir for 4-6 hours, and control the temperature ≤35°C;

[0028] Step 4: Add waterborne polyurethane dispersion, waterborne UV curable resin and isopropyl alcohol, stir for 0.5-1 hour, and control the temperature ≤35°C;

[0029] Step 5: Add photoinitiator TPO, stir for 1-1.5 hours, and control the temperature ≤35°C;

[0030] Step 6: Store in a light-proof container after quality inspection.

[0031] Furthermore, in order to limit the stirring speed and temperature control method and ensure the controllability of the preparation process, the stirring speed in steps 2 to 5 is 300-500 rpm, and condensed water is passed throughout the stirring process for temperature control.

[0032] Compared with the existing technology, the technical solution of this application has the following beneficial effects:

[0033] 1. The present invention achieves the purpose of providing excellent protective performance at extremely low dry film thickness through the synergistic effect of epoxy silane, zirconium carbonate, and waterborne polyurethane dispersion components, reducing the film thickness compared to traditional coatings. By introducing a light-activated system of photoinitiator TPO and waterborne UV-curing resin, the coating is endowed with ultraviolet-triggered self-repairing function, which can automatically repair microcracks and damage and extend the service life of the coating. By adopting a low-temperature curing formula, the curing temperature is reduced to less than 50% of that of traditional processes, significantly reducing energy consumption and carbon emissions. By controlling the molecular weight and solid content of the waterborne polyurethane dispersion, the flexibility and adhesion of the coating are optimized, making the coating less likely to crack during processing deformation.

[0034] 2. The present invention achieves the purpose of improving the corrosion resistance of the coating through the pH adjustment and cross-linking effect of triethanolamine and zirconium carbonate. The preparation process of staged temperature control is used to ensure that the components fully react without agglomeration or degradation, thereby ensuring the storage stability of the coating. By adding isopropyl alcohol as a film-forming aid, the purpose of improving the leveling and wettability of the coating is achieved, so that it can form a uniform and dense protective film on the surface of high aluminum, zinc, aluminum and magnesium.

[0035] 3. The present invention achieves rapid curing through a curing method that combines ultraviolet curing with thermal curing, improves production line efficiency, reduces coating consumption per ton of steel, and significantly reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a flow chart for preparing a chromium-free, fingerprint-resistant coating with self-repairing function specifically for high-aluminum-zinc-aluminum-magnesium coatings of the present invention;

[0037] Figure 2 Schematic diagram of each component embodiment of the present invention. DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0039] Example 1

[0040] A chrome-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium materials, comprising the following components by weight percentage:

[0041] Epoxy silane 3%;

[0042] Zirconium carbonate 2%;

[0043] Waterborne polyurethane dispersion 55%;

[0044] Photoinitiator TPO 2%;

[0045] Water-based UV curing resin 8%;

[0046] Triethanolamine 4%;

[0047] Coal-forming aid isopropyl alcohol 4%;

[0048] Deionized water 7%.

[0049] Specifically, the waterborne polyurethane dispersion has a solid content of 30% and a molecular weight of 5000. The photoinitiator TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and its ultraviolet absorption wavelength is 300 nm. The curing temperature is 50°C.

[0050] A method for preparing the chromium-free fingerprint-resistant coating comprises the following steps:

[0051] Step 1: Clean the stirring tank, add deionized water, and control the temperature at 30°C;

[0052] Step 2: Add triethanolamine and zirconium carbonate, stir for 1.5 hours, and control the temperature at 28°C;

[0053] Step 3: Add epoxy silane, stir for 4.5 hours, and control the temperature at 25°C;

[0054] Step 4: Add waterborne polyurethane dispersion, waterborne UV curable resin and isopropyl alcohol, stir for 1 hour, and control the temperature at 32°C;

[0055] Step 5: Add photoinitiator TPO, stir for 1 hour, and control the temperature at 35°C;

[0056] Step 6: Store in a light-proof container after quality inspection.

[0057] Specifically, the stirring speed is 400 rpm, and condensed water is passed through the stirring process for temperature control.

[0058] Example 2

[0059] A chrome-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium materials, comprising the following components by weight percentage:

[0060] Epoxy silane 4%;

[0061] Zirconium carbonate 3%;

[0062] Waterborne polyurethane dispersion 50%;

[0063] Photoinitiator TPO 2.5%;

[0064] Water-based UV curing resin 10%;

[0065] Triethanolamine 5%;

[0066] Coal-forming aid isopropyl alcohol 5%;

[0067] Deionized water 20.5%.

[0068] Specifically, the waterborne polyurethane dispersion has a solid content of 35% and a molecular weight of 6000. The photoinitiator TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, which has an ultraviolet absorption wavelength of 350 nm. The curing temperature is 55°C.

[0069] A method for preparing the chromium-free fingerprint-resistant coating comprises the following steps:

[0070] Step 1: Clean the stirring tank, add deionized water, and control the temperature at 25°C;

[0071] Step 2: Add triethanolamine and zirconium carbonate, stir for 1.5 hours, and control the temperature at 32°C;

[0072] Step 3: Add epoxy silane, stir for 5 hours, and control the temperature at 25°C;

[0073] Step 4: Add waterborne polyurethane dispersion, waterborne UV curable resin and isopropyl alcohol, stir for 1 hour, and control the temperature at 30°C;

[0074] Step 5: Add photoinitiator TPO, stir for 1 hour, and control the temperature at 28°C;

[0075] Step 6: Store in a light-proof container after quality inspection.

[0076] Specifically, the stirring speed is 300 rpm, and condensed water is passed through the entire stirring process for temperature control.

[0077] Example 3

[0078] A chrome-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium materials, comprising the following components by weight percentage:

[0079] Epoxy silane 5%;

[0080] Zirconium carbonate 4%;

[0081] Waterborne polyurethane dispersion 55%;

[0082] Photoinitiator TPO 3%;

[0083] Water-based UV curing resin 8%;

[0084] triethanolamine 6%;

[0085] Coal-forming aid isopropyl alcohol 4%;

[0086] Deionized water 15%.

[0087] Specifically, the waterborne polyurethane dispersion has a solid content of 40% and a molecular weight of 8000. The photoinitiator TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, which has an ultraviolet absorption wavelength of 350 nm. The curing temperature is 55°C.

[0088] A method for preparing the chromium-free fingerprint-resistant coating comprises the following steps:

[0089] Step 1: Clean the stirring tank, add deionized water, and control the temperature at 35°C;

[0090] Step 2: Add triethanolamine and zirconium carbonate, stir for 2 hours, and control the temperature at 35°C;

[0091] Step 3: Add epoxy silane, stir for 6 hours, and control the temperature at 35°C;

[0092] Step 4: Add waterborne polyurethane dispersion, waterborne UV curable resin and isopropyl alcohol, stir for 1 hour, and control the temperature at 35°C;

[0093] Step 5: Add photoinitiator TPO, stir for 1.5 hours, and control the temperature at 35°C;

[0094] Step 6: Store in a light-proof container after quality inspection.

[0095] Specifically, the stirring speed in steps 2 to 5 is 500 rpm, and condensed water is used to control the temperature during the stirring process.

[0096] Comparative Example

[0097] UNICHEMCOAT 8800, which is commonly used in the market, was used as a comparative example.

[0098] Experimental examples, coating performance test data

[0099] Examples 1-3 and the comparative example were coated on a high-aluminum-zinc-aluminum-magnesium substrate (aluminum content 55%). The test conditions and results are as follows:

[0100] 1. Basic performance test

[0101]

[0102] 2. Corrosion resistance test

[0103]

[0104] 3. Self-repair function verification

[0105]

[0106] 4. Economic comparison

[0107]

[0108] The present invention provides a chromium-free, fingerprint-resistant coating with self-repairing function specifically for high-aluminum zinc-aluminum-magnesium (ZAM) steel coils. Through innovative formula design and preparation process, the coating solves the problems of high curing temperature, large film thickness, and insufficient corrosion resistance of traditional coatings.

[0109] Specifically, a synergistic combination of photoinitiator TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide) and water-based UV-curable resin is used to trigger a cross-linking reaction under ultraviolet light to automatically repair micro-damage to the coating (such as scratches and cracks).

[0110] Repair efficiency: 50μm wide scratches are completely repaired after 1 hour of UV exposure

[0111] Specifically, through the synergistic cross-linking effect of epoxy silane and zirconium carbonate, low-temperature curing at 50-80°C is achieved, the dry film thickness is reduced to 0.2-0.5g / m² (20-30% of traditional coatings), and the curing time is shortened to 6-10 minutes (traditional processes require more than 15 minutes).

[0112] High-performance compound formula

[0113]

[0114] Comparison of technical effects

[0115]

[0116] Technical solution advantages

[0117] Environmental friendliness: Lower curing temperature reduces production line energy consumption by more than 40%, and the chromium-free formula complies with RoHS / REACH regulations.

[0118] Economical: Reducing the amount of coating reduces the cost per ton of steel by 150-200 yuan, and reduces equipment loss (low temperature operation extends the life of the oven).

[0119] Long-lasting protection: The self-repair function extends the coating life by 3-5 years, as verified by QUV accelerated aging tests: performance degradation is less than 10% after 3000 hours.

[0120] This invention is the first to apply light-activated self-healing technology to a chrome-free, fingerprint-resistant coating, addressing the high energy consumption and cost of traditional coatings. It has passed salt spray and damp heat tests and is suitable for industrial production. Its unique composition and process design significantly outperform commercially available products.

[0121] The above examples prove that the present invention achieves the purpose of providing excellent protective performance at extremely low dry film thickness through the synergistic effect of epoxy silane, zirconium carbonate, and waterborne polyurethane dispersion components, reducing the film thickness compared to traditional coatings. By introducing a light-activated system of photoinitiator TPO and waterborne UV curable resin, the coating is given the purpose of ultraviolet-triggered self-repair function, which can automatically repair microcracks and damage and extend the service life of the coating. By adopting a low-temperature curing formula, the curing temperature is reduced to less than 50% of the traditional process, significantly reducing energy consumption and carbon emissions. By controlling the molecular weight and solid content of the waterborne polyurethane dispersion, the purpose of optimizing the flexibility and adhesion of the coating is achieved, making the coating less likely to crack during processing deformation. The present invention achieves the purpose of improving the corrosion resistance of the coating through pH adjustment and cross-linking of triethanolamine and zirconium carbonate. Through a staged temperature control preparation process, the purpose of ensuring that each component fully reacts without agglomeration or degradation is achieved, ensuring the storage stability of the coating. By adding isopropyl alcohol as a film-forming aid, the purpose of improving the leveling and wettability of the coating is achieved, so that it can form a uniform and dense protective film on high-aluminum zinc aluminum magnesium surfaces. The present invention realizes rapid curing through a curing method combining ultraviolet curing with thermal curing, improves production line efficiency, reduces coating consumption per ton of steel, and significantly reduces production costs.

[0122] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0123] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium materials, characterized in that: Calculated by weight percentage, it includes the following components: Epoxy silane 3-5%; Zirconium carbonate 2-4%; Waterborne polyurethane dispersion 45-55%; Photoinitiator TPO 2-3%; Water-based UV curing resin 8-12%; Triethanolamine 4-6%; Coal-forming aid isopropyl alcohol 4-6%; Deionized water 7-22%.

2. The chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium according to claim 1, characterized in that: The waterborne polyurethane dispersion has a solid content of 30-40% and a molecular weight of 5000-10000.

3. The chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium according to claim 1, characterized in that: The photoinitiator TPO is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and its ultraviolet absorption wavelength is 300-400 nm.

4. The chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium according to claim 1, characterized in that: The water-based UV curable resin is a water-based resin containing acrylate functional groups, and its curing method is ultraviolet light-induced free radical polymerization.

5. The chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium materials according to claim 1, characterized in that: The dry film thickness of the coating is 0.2-0.5 g / m² and the curing temperature is 50-80°C.

6. The chromium-free, fingerprint-resistant coating with self-repairing function specially used for high-aluminum-zinc-aluminum-magnesium according to claim 1, characterized in that: The coating has a light-activated self-repairing function. Under ultraviolet irradiation, the photoinitiator TPO triggers the cross-linking reaction of the water-based UV curing resin to repair micro-damage to the coating.

7. A method for preparing the chromium-free fingerprint-resistant coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Clean the stirring tank, add deionized water, and control the temperature to ≤35°C; Step 2: Add triethanolamine and zirconium carbonate, stir for 1-2 hours, and control the temperature ≤35°C; Step 3: Add epoxy silane, stir for 4-6 hours, and control the temperature ≤35°C; Step 4: Add waterborne polyurethane dispersion, waterborne UV curable resin and isopropyl alcohol, stir for 0.5-1 hour, and control the temperature ≤35°C; Step 5: Add photoinitiator TPO, stir for 1-1.5 hours, and control the temperature ≤35°C; Step 6: Store in a light-proof container after quality inspection.

8. The chromium-free, fingerprint-resistant coating with self-repairing function specifically for high-aluminum-zinc-aluminum-magnesium materials according to claim 7, characterized in that: The stirring speed in steps 2 to 5 is 300-500 rpm, and condensed water is passed throughout the stirring process to control the temperature.

9. An application of the chromium-free fingerprint-resistant coating according to any one of claims 1 to 6, characterized in that: The coating is used for surface protection of high-aluminum-zinc-aluminum-magnesium steel coils for outdoor buildings, solar energy supports, greenhouses or power transmission and distribution equipment.

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