Metal decorative plate, preparation method thereof and refrigerator

Abstract

The invention discloses a metal decorative plate, a preparation method thereof and a refrigerator, and belongs to the field of household appliance decorative panels. According to the technical scheme, the method comprises an ultra-matte skin feeling layer curing step, and the ultra-matte skin feeling layer curing step comprises the steps that leveling treatment is carried out on a coating coated on the surface of a base plate, surface deoxidization is carried out after leveling treatment, surface pre-curing is carried out by adopting ultraviolet rays of a first wavelength after surface deoxidization, and the ultra-matte skin feeling layer is obtained. After the surface is pre-cured, ultraviolet rays with a second wavelength are adopted for complete curing, and an ultra-matte skin feeling layer with micro lines is obtained; the first wavelength is 172 + / -3nm; the second wavelength is not less than 340nm; the coating comprises polyester acrylic resin, epoxy acrylic resin, gas-phase silicon and an auxiliary agent. The metal decoration plate is applied to the aspect of household appliance decoration panels, and the problems that an existing metal decoration plate is high in surface glossiness and poor in surface skin feeling are solved.

Description

Technical Field

[0001] This invention belongs to the field of decorative panels for household appliances, and particularly relates to a metal decorative panel, its preparation method, and a refrigerator. Background Technology

[0002] As people's consumption levels and concepts improve, home appliances are no longer simple tools but have been given a decorative function. Therefore, consumers have increasingly higher demands for the appearance of home appliances. Metal decorative panels, with their metallic texture and rich appearance, meet users' aesthetic needs and are the preferred material for home appliance casings. However, currently available ultra-matte finish panels suffer from high surface gloss, poor chemical resistance, and low surface hardness.

[0003] Products with a skin-like finish are made by applying a UV-cured PET decorative film to the surface of steel plates. Currently, only LG in South Korea can produce ultra-low gloss skin-like decorative films with UV treatment, and these products are very expensive. Products with a skin-like finish made by coating the surface of steel plates with polyester coatings are prone to discoloration and delamination under alkaline conditions, failing to meet the requirements for use in home appliances. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the technical problem to be solved by the present invention is that the surface gloss of existing metal decorative panels is high but the surface feel is poor. The present invention proposes a metal decorative panel with low surface gloss and a skin-friendly surface, its preparation method and a refrigerator.

[0005] To solve the aforementioned technical problem, the technical solution adopted by the present invention is as follows:

[0006] This invention provides a method for preparing a metal decorative panel, including a super matte skin-feel layer curing step, the super matte skin-feel layer curing step comprising:

[0007] The coating on the substrate surface is leveled, and then the surface is deoxygenated. After the surface is deoxygenated, the surface is pre-cured using ultraviolet light of the first wavelength. After the surface is pre-cured, the surface is fully cured using ultraviolet light of the second wavelength to obtain an ultra-matte skin-feel layer with micro-texture.

[0008] The first wavelength is 172±3nm; the second wavelength is not less than 340nm;

[0009] Coatings include polyester acrylic resins, epoxy acrylic resins, fumed silicone, and additives.

[0010] In some embodiments, the first wavelength is 172 nm; the second wavelength is 550 nm.

[0011] In some embodiments, the amount of polyester acrylate resin is selected from any value of 25-45% by mass percentage, the amount of epoxy acrylate resin is selected from any value of 10-30%, the amount of fumed silica is selected from any value of 1-3%, and the amount of additives is selected from any value of 1-2%.

[0012] In some embodiments, the amount of epoxy acrylate resin is selected from any value of 25-30% by mass percentage, the amount of fumed silica is selected from any value of 1.5-3%, and the amount of additives is selected from any value of 1-2%.

[0013] In some embodiments, the coating further includes reactive monomers and pigments, wherein the amount of reactive monomers is any value of 20-30% by mass percentage, and the amount of pigments is any value of 3-7%.

[0014] In some embodiments, the coating is composed of polyester acrylate, epoxy acrylate, reactive monomer, fumed silica, pigment, and additives.

[0015] In some embodiments, the ultra-matte skin-feel layer curing step includes:

[0016] The ultra-matte skin-feel layer is coated with polyurethane acrylic resin, with a coating amount of 20-30 g / m². 2 After entering the flow channel for leveling, the surface undergoes deoxygenation through a closed-loop air knife system. Once the residual oxygen on the surface is zero, it is pre-cured using a 172nm excimer lamp. After pre-curing, it is cured with a mercury lamp at full wavelength with an energy of 500-700 mJ / cm². 2 This allows the surface coating to fully cure.

[0017] In another aspect, the present invention provides a method for preparing a metal decorative panel according to any of the above technical solutions. The metal decorative panel is prepared by coating an ultra-matte skin-feel layer on its surface. The ultra-matte skin-feel layer has an uneven surface with a wavelength of 5-10 μm and a wavelength of 1-3 μm.

[0018] In some embodiments, the substrate includes a substrate, the front side of which is sequentially provided with a first chromium-free passivation layer, a primer anti-corrosion layer, a high salt spray performance layer, a first ink printing layer, a second ink printing layer, a third ink printing layer and an ultra-matte skin-feel layer; the back side of the substrate is sequentially provided with a second chromium-free passivation layer and an epoxy back coating layer.

[0019] The thickness of the first and second chromium-free passivation layers is any value between 1 and 5 μm; the substrate is any one of galvanized steel, stainless steel, cold-rolled steel, or aluminum-magnesium-zinc coated steel; the thickness of the substrate is any value between 0.3 and 1.0 mm; the high salt spray performance layer is a chlorinated polypropylene resin coating or an α-methylstyrene layer, with a thickness of any value between 10 and 30 μm; the thickness of the first, second, and third ink printing layers is any value between 1 and 10 μm.

[0020] The present invention also provides a refrigerator, the outer shell of which includes a metal decorative panel of any of the above-described technical solutions.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] This invention provides a method for preparing a metal decorative panel, which uses a coating comprising polyester acrylate resin, epoxy acrylate resin, fumed silica, and additives. The coating is irradiated with ultraviolet light of a specific wavelength, and is first pre-cured with ultraviolet light of wavelength 172±3nm, and then fully cured with ultraviolet light of a second wavelength. This results in different curing rates for the surface and the bottom layer of the UV coating, thereby forming micro-textures on the coating surface and achieving an ultra-low gloss and skin-feel effect.

[0023] This invention provides a metal decorative panel with low surface gloss and a skin-friendly texture. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the layer structure of the metal decorative panel provided in an embodiment of the present invention;

[0025] Figure 2 This is a diagram showing the surface effect of the paint layer in Embodiment 1 of the present invention;

[0026] Figure 3 This is another surface effect diagram of the paint layer in Embodiment 1 of the present invention;

[0027] In the above figures: 1. Substrate; 2. First chromium-free passivation layer; 3. Primer anti-corrosion layer; 4. High salt spray performance layer; 5. First ink printing layer; 6. Second ink printing layer; 7. Third ink printing layer; 8. Ultra-matte skin-feel layer; 9. Second chromium-free passivation layer; 10. Epoxy back coating layer. Detailed Implementation

[0028] The technical solutions in specific embodiments of the present invention will be described in detail and completely below. Obviously, the described embodiments are only some specific implementations of the overall technical solution of the present invention, and not all implementations. Based on the overall concept of the present invention, all other embodiments obtained by those skilled in the art fall within the protection scope of the present invention.

[0029] A method for preparing a metal decorative panel includes a curing step for an ultra-matte skin-feel layer.

[0030] In some embodiments, the curing step of the ultra-matte skin-feel layer 8 includes: leveling the coating applied to the surface of the substrate 1.

[0031] Leveling is the key to ensuring the appearance of the obtained ultra-matte skin-feel layer 8. It may affect the smoothness and flatness of the ultra-matte skin-feel layer 8. Through leveling, the wet coating that has just been applied to the substrate 1 and has construction marks (such as brush marks, roller marks, spray dots) can be naturally flowed and become flat and smooth under the drive of surface tension.

[0032] In some embodiments, the curing step of the ultra-matte skin-feel layer 8 includes: surface deoxygenation after leveling treatment.

[0033] Traditional curing processes result in incomplete curing (sticky surface) of the coating due to oxygen inhibition on the coating surface, requiring nitrogen protection or highly active amine additives, which increases manufacturing costs and VOC emissions. The ultra-matte skin-feel layer provided by this invention only requires reducing the oxygen content of the coating area, reducing oxygen inhibition on the coating surface, eliminating the need for inert gas protection, and improving production efficiency by more than 30%.

[0034] In some embodiments, the curing step of the ultra-matte skin-feel layer 8 includes: surface pre-curing with ultraviolet light of a first wavelength after surface deoxygenation, wherein the first wavelength is 172±3nm.

[0035] As mentioned above, in traditional curing processes, the coating surface is affected by oxygen inhibition, resulting in incomplete curing (sticky surface). This requires nitrogen protection or highly active amine additives, increasing manufacturing costs and VOC emissions. The ultra-matte skin-feel layer provided by this invention only requires reducing the oxygen content in the coating area, thus reducing the oxygen inhibition phenomenon on the coating surface. During pre-curing, 172±3nm light wave energy (7.2eV) is used, which is greater than the O2 bond energy (5.1eV). This can directly dissociate oxygen to generate ozone and atomic oxygen, which in turn promotes surface cross-linking. As a result, the surface hardness of the coating is increased by more than 20%, and no inert gas protection is required, increasing production efficiency by more than 30%.

[0036] Furthermore, traditional UVC light sources rely on photoinitiators to generate free radicals. Residual initiators may reduce yellowing resistance and have an oxygen inhibition effect. The 172±3nm light wave generates high-energy ultraviolet photons that directly break the CC / CH bonds of acrylate, achieving "photoinitiator-free" curing. Its advantages include eliminating small molecule migration problems and improving coating purity and weather resistance. The coating crosslinking network is more uniform, hardness is increased by 15-20% (pencil hardness can reach 4H), and the long-term yellowing index ΔE < 1 (compared to ΔE > 3 for traditional processes).

[0037] Traditional UV curing equipment operates at temperatures above 120°C. Prolonged exposure to high temperatures can prevent the release of internal stress in the metal substrate 11, leading to bending and deformation, which in turn affects the appearance quality of the color-coated steel sheet. Curing with 172±3nm light waves keeps the substrate surface temperature below 80°C, effectively preventing thermal deformation of the steel sheet and reducing thermal stress on the surface coating. This also effectively prevents micro-cracking of the coating and improves the physical and chemical properties of the color-coated steel sheet. In some embodiments, the first wavelength is 172nm.

[0038] In some embodiments, the curing step of the ultra-matte skin-feel layer 8 includes: after surface pre-curing, it is fully cured by ultraviolet light of a second wavelength to obtain an ultra-matte skin-feel layer 8 with micro-textures, wherein the second wavelength is not less than 340nm.

[0039] The ultra-matte skin-feel layer curing step provided by this invention involves irradiation with ultraviolet light of a specific wavelength. First, a 172nm wavelength ultraviolet light is used for pre-curing, followed by a second wavelength ultraviolet light for complete curing. This results in different curing rates for the surface and the underlying layer of the UV coating, creating micro-textures on the coating surface and achieving an ultra-low gloss and skin-feel effect. In some embodiments, the second wavelength is 550nm.

[0040] In some embodiments, the coating comprises a polyester acrylate resin, the amount of which, by weight percentage, is selected from any value between 25% and 45%. It is understood that the amount of polyester acrylate resin may also be any point value within the range of 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, and so on.

[0041] The ultra-matte skin-feel layer 8 of the present invention is a polyurethane acrylic resin. By irradiating with ultraviolet light of a specific wavelength, the curing rate of the UV coating surface and the bottom layer are different, thereby forming micro-textures on the coating surface, thus achieving ultra-low gloss and skin-feel effect.

[0042] In some embodiments, the coating comprises an epoxy acrylate resin, the amount of which, by weight percentage, is selected from any value between 10% and 30%. It is understood that the amount of epoxy acrylate resin may also be any point value within the range of 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and so on.

[0043] The amount of epoxy acrylate resin used affects the surface microtexture effect of the material, which in turn affects the gloss and skin-friendly texture of the ultra-matte skin-feel layer 8. In some embodiments, the amount of epoxy acrylate resin used, by weight percentage, is selected from any value between 25% and 30%.

[0044] In some embodiments, the coating comprises fumed silica, the amount of which, by weight percentage, is selected from any value between 1% and 3%. It is understood that the amount of fumed silica can also be any point value within the range of 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%.

[0045] The amount of fumed silica affects the hardness of the ultra-matte skin-feel layer 8. In some embodiments, the amount of fumed silica is selected from any value between 1.5% and 3% by mass percentage.

[0046] In some embodiments, the coating includes an additive, the amount of which, by weight percentage, is selected from any value between 1% and 2%. It is understood that the amount of the additive may also be any point value within the range of 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%.

[0047] The amount of additives used affects the leveling properties and surface smoothness of the product during the production process. In some embodiments, the amount of additives used is selected from any value between 1% and 2% by mass percentage.

[0048] It should be noted that this invention uses a specific 172nm wavelength ultraviolet light to pre-cur the surface coating. The penetration depth of this specific wavelength ultraviolet light is only 100-600nm. Therefore, only a very thin layer of coating on the surface is cured. After the complete curing process, due to the different reaction conditions on the surface and inside, the surface and inside of the coating shrink at different degrees. As a result, micro-textures are formed on the surface of the cured coating. When the human body comes into contact with the coating, it will have a soft and skin-friendly feeling. Moreover, because of the different distribution of micro-textures, the surface gloss of the coating will also change.

[0049] This invention provides a method for preparing an ultra-matte, skin-feeling metal decorative panel. By adjusting the formula and improving the processing technology, the surface gloss of the color steel plate is less than 10°, the surface has a skin-friendly texture, and the material has excellent chemical resistance, which can meet the performance requirements of home appliance surface decoration. In addition, ultra-matte and skin-friendly textures can be made according to consumer needs, satisfying consumers' demand for differentiated appearance of home appliances.

[0050] In some embodiments, the coating further includes an active monomer, wherein the amount of the active monomer is any value between 20% and 30% by mass percentage. It is understood that the amount of the active monomer can also be any point value within the range of 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%.

[0051] In some embodiments, the coating also includes pigments, with the pigments used in any amount from 3% to 7% by weight. The pigments are used to color ultra-matte metallic decorative panels, and it is understood that the amount of pigment used can also be any point value within the range of 4%, 5%, 6%, 7%, 8%, 9%.

[0052] The above preparation method is simple and easy to operate, with low production cost. The prepared colored super matte decorative panel with three-dimensional texture has vibrant colors and no initiator residue on the surface; there is no cracking, and the surface texture of the decorative panel is very fine; it has low gloss and a super matte effect and skin-feel effect at a 60° incident angle of 5-10°. This invention is applied to the decorative panels of household appliance shells, solving the problems of high surface gloss and poor chemical resistance of existing metal decorative panels, achieving the ultra-low gloss appearance requirement of household appliance decorative panels, and improving the insufficient chemical resistance of color steel plates in skin-feel treatment.

[0053] In some embodiments, the coating is composed of polyester acrylate, epoxy acrylate, reactive monomer, fumed silica, pigment, and additives.

[0054] Traditional UVC light sources rely on photoinitiators to generate free radicals. Residual initiators may reduce yellowing resistance and have an oxygen-inhibiting effect. This invention uses 172nm ultraviolet light for pre-curing. The 172nm light generates high-energy ultraviolet photons that directly break the CC / CH bonds of acrylate, achieving "photoinitiator-free" curing. The coating used in this invention does not contain photoinitiators, which helps eliminate small molecule migration problems and improves coating purity and weather resistance. Simultaneously, the coating crosslinking network is more uniform, hardness is increased by 15-20% (pencil hardness can reach 4H), and the long-term yellowing index ΔE < 1 (compared to ΔE > 3 in traditional processes).

[0055] In some embodiments, the curing step of the ultra-matte skin-feel layer 8 includes: the ultra-matte skin-feel layer 8 is coated with polyurethane acrylic resin, with a coating amount of 20-30 g / m². 2 After entering the flow channel for leveling, the surface undergoes deoxygenation through a closed-loop air knife system. Once the residual oxygen on the surface is zero, it is pre-cured using a 172nm excimer lamp. After pre-curing, it is cured with a mercury lamp at full wavelength with an energy of 500-700 mJ / cm². 2 This allows the surface coating to fully cure.

[0056] Understandably, the coating amount could still be 21 g / m².2 22g / m 2 23g / m 2 24g / m 2 25g / m 2 26g / m 2 27g / m 2 28g / m 2 29g / m 2 and any point value within its range.

[0057] In another aspect, the present invention provides a method for preparing a metal decorative panel according to any of the above-mentioned technical solutions. The metal decorative panel obtained is coated with an ultra-matte skin-feel layer 8, which has an uneven surface with a wavelength of 5-10 μm and a wavelength of 1-3 μm. The uneven surface with a wavelength of 5-10 μm and a wavelength of 1-3 μm gives the metal decorative panel the characteristics of low gloss and a skin-friendly texture.

[0058] Understandably, the wavelength can be any value within the range of 6μm, 7μm, 8μm, 9μm, and 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2.0μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, and 1.2μm.

[0059] like Figure 1 As shown, the metal decorative panel includes a substrate 1. The front side of the substrate 1 is sequentially provided with a first chromium-free passivation layer 2, a primer anti-corrosion layer 3, a high salt spray performance layer 4, a first ink printing layer 5, a second ink printing layer 6, a third ink printing layer 7, and an ultra-matte skin-feel layer 8. The back side of the substrate 1 is sequentially provided with a second chromium-free passivation layer 9 and an epoxy back coating layer 10. The ultra-matte skin-feel layer 8 is attached to the third ink printing layer.

[0060] This invention uses UV resin condensation to form a matte micro-surface, creating an ultra-low matte skin-feel topcoat layer that serves a decorative and aesthetic purpose while improving the surface properties of the coating.

[0061] In some embodiments, the thickness of the first chromium-free passivation layer 2 is any value between 1 and 5 μm. It is understood that the thickness of the first chromium-free passivation layer 2 can also be any value within the range of 2 μm, 3 μm, 4 μm, etc.

[0062] In some embodiments, the thickness of the second chromium-free passivation layer 9 is any value between 1 and 5 μm. It is understood that the thickness of the second chromium-free passivation layer 9 can also be any value within the range of 2 μm, 3 μm, 4 μm, etc.

[0063] In some embodiments, the substrate 1 is any one of galvanized sheet, stainless steel, cold-rolled steel, and aluminized magnesium zinc sheet; the thickness of the substrate 1 is any value between 0.3 and 1.0 mm. It is understood that the thickness of the substrate 1 can also be any value within the range of 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, etc.

[0064] In some embodiments, the high salt spray performance layer 4 is a chlorinated polypropylene resin coating or an α-methylstyrene layer, with a thickness of any value between 10 and 30 μm. It is understood that the thickness of the high salt spray performance layer 4 can also be any value within the range of 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, and above.

[0065] In some embodiments, the thickness of the first ink printing layer 5 is any value between 1 and 10 μm. It is understood that the thickness of the first ink printing layer 5 can also be any value within the range of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and above.

[0066] In some embodiments, the thickness of the second ink printing layer 6 is any value between 1 and 10 μm. It is understood that the thickness of the second ink printing layer 6 can also be any value within the range of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, etc.

[0067] In some embodiments, the thickness of the third ink printing layer 7 is any value between 1 and 10 μm. It is understood that the thickness of the third ink printing layer 7 can also be any value within the range of 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, etc.

[0068] The present invention also provides a refrigerator, the outer shell of which includes a metal decorative panel of any of the above-described technical solutions.

[0069] To provide a clearer and more detailed description of the metal decorative panel, its preparation method, and the refrigerator provided in the embodiments of the present invention, the following description will be based on specific embodiments.

[0070] The raw material composition used in the following embodiments and comparative examples is shown in Table 1.

[0071] Table 1 Raw Materials

[0072] raw material factory Brand Polyurethane acrylic resin Bulin Chemicals, South Korea BA-9523 Epoxy Acrylic Resin Bulin Chemicals, South Korea TC-3395 active monomers Bulin Chemicals, South Korea MO-235 Vaporized silicon degusa OK500 pigment DK Chemicals, South Korea MR-107 Additives BYK BYK-1790

[0073] Unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods used by those skilled in the art.

[0074] The specific test items are as follows:

[0075] 1. Surface wave height and width: measured using a Dongguan Bosheng BC4K-3630 electron microscope;

[0076] 2. Surface gloss: Gloss was measured at a 60° angle using a Mitotoyo gloss meter (Japan).

[0077] 3. The chemical resistance test method is as follows:

[0078] GB / T 13448, the cut of the specimen (75mm×150mm) is completely sealed, and then immersed in a 5% HCl solution at room temperature (23±2℃). After 24h, the specimen is taken out, rinsed, and the coated side surface is inspected.

[0079] -GB / T 13448, the cut of the specimen (75mm×150mm) is completely sealed, and it is immersed in a 5% NaOH solution at room temperature (23±2℃). After 24h, it is taken out, rinsed and the surface of the coated side of the specimen is inspected.

[0080] 4. The surface hardness test method is as follows: the surface pencil hardness test is performed in accordance with GB / T 13448 standard.

[0081] Example 1

[0082] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0083] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0084] Example 2

[0085] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0086] The preparation steps for the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, then enters the curing stage, passing through a closed air knife for oxygen removal; after the surface residual oxygen is zero, it is pre-cured using a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage, cured with a mercury lamp at the full wavelength (wavelength of 340nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0087] Example 3

[0088] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0089] Preparation steps of the matte skin-feel layer: The coating containing the above components enters the channel for leveling, then enters the curing stage, passing through a closed air knife deoxygenation channel; after the surface residual oxygen is zero, it is pre-cured with a 169nm excimer lamp. After pre-curing, it enters the UV full curing stage, cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0090] Example 4

[0091] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0092] The preparation steps for the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, then enters the curing stage, passing through a closed air knife for oxygen removal; after the surface residual oxygen is zero, it is pre-cured using a 175nm excimer lamp. After pre-curing, it enters the UV full curing stage, cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0093] Example 5

[0094] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0095] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0096] Example 6

[0097] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0098] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0099] Example 7

[0100] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0101] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0102] Example 8

[0103] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0104] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0105] Example 9

[0106] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0107] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife deoxygenation channel. After the surface residual oxygen is zero, it is pre-cured with a 172nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0108] Comparative Example 1

[0109] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0110] The preparation steps of the matte skin-feel layer are as follows: The coating containing the above components enters the channel for leveling, and then enters the curing stage. It passes through a closed air knife for oxygen removal. After the surface residual oxygen is zero, it is pre-cured with a 254nm excimer lamp. After pre-curing, it enters the UV full curing stage and is cured with a mercury lamp at the full wavelength (wavelength of 550nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0111] Comparative Example 2

[0112] The formulation for the matte finish coating consists of: polyurethane acrylate resin, epoxy acrylate resin, reactive monomers, fumed silica, pigments, and additives. The amounts of each raw material are shown in Table 3.

[0113] Preparation steps of the matte skin-feel layer: The coating containing the above components enters the channel for leveling, then enters the curing stage, passing through a closed air knife deoxygenation channel; after the surface residual oxygen is zero, it is pre-cured with a 254nm excimer lamp. After pre-curing, it enters the UV full curing stage, cured with a mercury lamp at the full wavelength (wavelength of 340nm) at an energy of 500mj / cm². 2 This allows the surface coating to fully cure.

[0114] Performance testing

[0115] Different wavelengths of ultraviolet light were selected for curing treatment (Examples 1, 2, 3, and 4; Comparative Examples 1 and 2). Through the combination of surface pre-curing and complete bottom-layer curing, micro-textures were achieved on the coating surface. The wave height and width of the micro-textures achieved ultra-low gloss and a skin-friendly texture. Ultraviolet light with wavelengths of 172nm and 254nm was selected for the pre-curing stage, and ultraviolet light with wavelengths of 340nm and 550nm was selected for the complete curing stage. The optimal method was determined using an experimental matrix. The test results for Examples 1, 2, 3, and 4, and Comparative Examples 1 and 2 are shown in Table 2.

[0116] Table 2 shows the test results of Examples 1, 2, 3, and 4 and Comparative Examples 1 and 2.

[0117]

[0118] Table 3 shows that when Comparative Example 1 and Comparative Example 2 were pre-cured using a conventional 254nm UVC wavelength, the pre-cured surface layer and the underlying resin did not form an effective tensile force, and no micro-textures were generated on the coating surface, making it impossible to achieve ultra-low gloss and skin-feel effects.

[0119] Examples 1 and 2 used a specific 172nm UV wavelength for pre-curing. The pre-cured surface layer and the underlying resin formed an effective stretching effect, creating micro-textures on the coating surface, achieving ultra-low gloss and a skin-like feel. In Example 1, the pre-cured surface layer and the underlying resin formed a strong stretching effect, resulting in clear and uniform micro-textures on the coating surface, and optimal surface gloss and skin-friendly texture. The surface effect of the paint layer in Example 1 is as follows: Figure 2 , 3 As shown.

[0120] Table 3. Formulation composition of the examples and comparative examples

[0121]

[0122]

[0123] The performance test results of the above embodiments are shown in Table 4.

[0124] Table 4 Performance Test Results

[0125] Test Project Example 1 Example 5 Example 6 Example 7 Example 8 Example 9 Wavewidth 8 6 3 6 4 8 wave height 2 4 2 2 4 6 Skin feel and texture powerful weak weak powerful weak powerful Chemical resistance qualified qualified qualified qualified qualified qualified Surface hardness 2H 2H 1H 1H 2H 2H Surface gloss 8° 17° 15° 13° 14° 13°

[0126] The test results show that, compared with Example 5, increasing the amount of epoxy acrylic resin added in Example 1 resulted in a more obvious surface micro-texture effect and a stronger skin-friendly texture. However, because the PV value of the surface micro-texture was reduced, the surface gloss was higher and it was impossible to achieve an ultra-matte effect below 10°.

[0127] Examples 6 and 7 reduced the amount of fumed silicon material added, resulting in a decrease in the surface hardness of the material, with the surface hardness decreasing from 2H to 1H. This increases the risk of scratch damage when used as a decorative material for household appliances.

[0128] Examples 8 and 9 reduced the amount of additives, which led to a decrease in the leveling properties of the product during the production process, making it prone to foaming problems, resulting in a decrease in surface smoothness and a gloss level that could not be achieved below 10°.

Claims

1. A method for preparing a metal decorative panel, characterized in that, The process includes a super matte skin-feel layer curing step, which includes: The coating on the substrate surface is leveled, and then the surface is deoxygenated. After the surface is deoxygenated, the surface is pre-cured using ultraviolet light of the first wavelength. After the surface is pre-cured, the surface is fully cured using ultraviolet light of the second wavelength to obtain an ultra-matte skin-feel layer with micro-texture. The first wavelength is 172±3nm; the second wavelength is not less than 340nm; The coating comprises polyester acrylate resin, epoxy acrylate resin, fumed silica, and additives.

2. The method for preparing the metal decorative panel according to claim 1, characterized in that, The first wavelength is 172nm; the second wavelength is 550nm.

3. The method for preparing the metal decorative panel according to claim 1, characterized in that, The amount of the polyester acrylate resin is selected from any value of 25-45% by mass percentage, the amount of the epoxy acrylate resin is selected from any value of 10-30%, the amount of the fumed silica is selected from any value of 1-3%, and the amount of the additives is selected from any value of 1-2%.

4. The method for preparing the metal decorative panel according to claim 3, characterized in that, The amount of epoxy acrylate resin is selected from any value of 25-30% by mass percentage, the amount of fumed silica is selected from any value of 1.5-3%, and the amount of additives is selected from any value of 1-2%.

5. The method for preparing a metal decorative panel according to claim 1, characterized in that, The coating also includes reactive monomers and pigments, wherein the amount of reactive monomers is any value between 20% and 30% by mass percentage, and the amount of pigments is any value between 3% and 7%.

6. The method for preparing a metal decorative panel according to claim 1, characterized in that, The coating is composed of polyester acrylate, epoxy acrylate, reactive monomers, fumed silica, pigments, and additives.

7. The method for preparing a metal decorative panel according to claim 1, characterized in that, The curing step of the ultra-matte skin-feel layer includes: The ultra-matte skin-feel layer is coated with polyurethane acrylic resin with a coating amount of 20-30 g / m². 2 After entering the flow channel for leveling, the surface undergoes deoxygenation through a closed-loop air knife system. Once the residual oxygen on the surface is zero, it is pre-cured using a 172nm excimer lamp. After pre-curing, it is cured with a mercury lamp at full wavelength with an energy of 500-700 mJ / cm². 2 This allows the surface coating to fully cure.

8. The metal decorative panel prepared by the method according to any one of claims 1-7, characterized in that, The surface of the metal decorative panel is covered with the ultra-matte skin-feel layer, which has an uneven surface with a wavelength of 5-10 μm and a wavelength of 1-3 μm.

9. The metal decorative panel according to claim 8, characterized in that, The substrate includes a first chromium-free passivation layer, a primer anti-corrosion layer, a high salt spray performance layer, a first ink printing layer, a second ink printing layer, a third ink printing layer, and the ultra-matte skin-feel layer, which are sequentially disposed on the front side of the substrate; and a second chromium-free passivation layer and an epoxy back coating layer are sequentially disposed on the back side of the substrate. The thickness of the first chromium-free passivation layer and the second chromium-free passivation layer is any value between 1 and 5 μm; the substrate is any one of galvanized steel, stainless steel, cold-rolled steel, and aluminum-magnesium-zinc coated steel; the thickness of the substrate is any value between 0.3 and 1.0 mm; the high salt spray performance layer is a chlorinated polypropylene resin coating or an α-methylstyrene layer, with a thickness of any value between 10 and 30 μm; the thickness of the first ink printing layer, the second ink printing layer, and the third ink printing layer is any value between 1 and 10 μm.

10. A refrigerator, characterized in that, The refrigerator's outer casing includes the metal decorative panel as described in claim 8 or 9.

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