Skin-friendly UV coating and preparation method thereof

Abstract

According to the skin-friendly UV coating provided by the embodiment of the invention, multi-section UV curing is carried out by using multi-section UV curing equipment, and the multi-section UV curing equipment comprises a first-section curing area, a second-section curing area and a third-section curing area; a UVA-LED curing lamp is arranged in the first-section curing area to form a high-wavelength part curing area; a UVC excimer curing lamp is arranged in the second-section curing area to form a low-wavelength part curing area; a UVA mercury lamp curing lamp is arranged in the third-section curing area, the wavelength of the UVA mercury lamp curing lamp is higher than that of the UVC excimer curing lamp in the second-section curing area and smaller than that of the UVA-LED curing lamp in the first-section curing area, and a curing effect shaping area with the middle wavelength is formed. According to the invention, a plurality of functional connecting materials are matched, and then special multi-section curing equipment is used for curing, so that the smooth and elastic skin-friendly UV coating is provided.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, and particularly relates to a skin-friendly UV coating and its preparation method. Background Technology

[0002] With the continuous development of social production and life, people's requirements for industrial products such as electronic products and automobiles are also increasing, such as the ever-increasing demands on the surface of electronic products and automotive interiors. The traditional method is ultraviolet (UV) curing. However, the current UV curing method involves passing the product surface through a UV lamp with a fixed wavelength for curing. When high surface finish requirements are needed, traditional curing methods cannot meet the requirements, or require multiple curing processes, resulting in low product yield, low production efficiency, high production costs, and difficulty in achieving the desired surface finish.

[0003] Therefore, it is necessary to provide a skin-friendly UV coating suitable for multi-stage curing and its preparation method to solve the above problems. Summary of the Invention

[0004] In order to address at least one of the aforementioned problems and defects in the prior art, embodiments of the present invention provide a skin-friendly UV coating suitable for multi-stage curing and a method for preparing the same.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] In a first aspect of the invention, a skin-friendly UV coating is provided, comprising a base agent and a diluent.

[0007] The main agent is composed of the following components in parts by weight:

[0008]

[0009]

[0010] The diluent consists of the following components in parts by weight:

[0011] Ethyl acetate 50-100;

[0012] Butyl acetate 0-50.

[0013] Preferably, the α-hydroxyalkyl phenyl ketone cleavage-type free radical photoinitiator is selected from, for example, IGM's Omnirad 184 and / or Omnirad 1173.

[0014] Preferably, the acylphosphine oxide pyrolysis type free radical photoinitiator is selected from, for example, IGM's Omnirad TPO and / or Omnirad 819.

[0015] Preferably, the hydrogen-abstracting free radical photoinitiator is, for example, IGM's Omnirad MBF.

[0016] Preferably, the elastic polyurethane acrylate UV resin is, for example, LUXYDIRZHU-1966 with 2-3 functionality of DIC.

[0017] Preferably, the silicone-modified polyurethane acrylate UV resin is, for example, commercially available 5-functionality B-828.

[0018] Preferably, the amine-modified polyester acrylate UV resin is, for example, U-CURE9230, a dual-functional polymer from Castel Polymer.

[0019] Preferably, the excimer UV resin is selected from, for example, commercially available 3-functionality L-6367-2 and L-6367-3, or commercially available 4-functionality W4480L and W4485S, or any combination thereof.

[0020] Preferably, the pure acrylic resin is, for example, commercially available WJ-468.

[0021] Preferably, the matting agent is, for example, commercially available E-1011.

[0022] Preferably, the wetting agent is, for example, commercially available TEGO Rad 2200N.

[0023] Preferably, the leveling agent is, for example, commercially available TEGO FlowATF2.

[0024] In a second aspect of the present invention, a method for preparing a skin-friendly UV coating suitable for multi-stage curing is provided, comprising the following steps:

[0025] 1) Preparation of photoinitiator dispersion

[0026] S1. In a dispersion container, ethyl acetate and butyl acetate solvents are mixed in a preset ratio and stirred to obtain a dispersion.

[0027] S2. Photoinitiator 184 / 1173, photoinitiator TPO / 819, and photoinitiator MBF are added slowly and sequentially to the dispersion obtained in step S1 during stirring. The mixture is dispersed until it is uniform. After the addition is complete, the stirring speed is increased and the mixture is dispersed for a certain period of time. The mixture is then filtered to obtain the photoinitiator dispersion.

[0028] 2) Preparation of skin-friendly UV coatings

[0029] S3. In a dispersion container, add elastic polyurethane acrylate UV resin, silicone-modified polyurethane acrylate UV resin, amine-modified polyester acrylate UV resin, excimer UV resin, and pure acrylic resin in sequence according to the proportion, and stir and disperse until uniform to obtain the first mixture.

[0030] S4. Slowly add the matting powder to the first mixture obtained in step S3 during the stirring process, disperse it until it is uniform, increase the stirring speed after the addition is complete, and continue to disperse for a certain period of time to obtain the second mixture.

[0031] S5. Wetting agent and leveling agent are slowly added to the second mixture in step S4 during the stirring process, and dispersed until uniform to obtain the third mixture;

[0032] S6. UV monomers HEMA, HDDA, and DPHA are slowly added to the third mixture in step S5 in sequence during stirring, and dispersed until uniform to obtain the fourth mixture.

[0033] S7. Slowly add propylene glycol methyl ether acetate solvent to the fourth mixture in step S6 and disperse until uniform to obtain the fifth mixture;

[0034] S8. Slowly add the photoinitiator dispersion obtained in step 1) to the fifth mixture in step S5. After the addition is complete, increase the stirring speed to disperse until uniform. Filter to obtain the skin-friendly UV coating.

[0035] The skin-friendly UV coating and its preparation method provided by the embodiments of the present invention have at least one or a portion of the following advantages:

[0036] 1) This skin-friendly UV coating uses a variety of different functional resins as the main binders, resulting in a soft, smooth, and delicate surface effect;

[0037] 2) By combining various functional modified UV resins, compared with conventional polyurethane acrylate UV resins, it also has the functions of scratch resistance, fingerprint resistance, wear resistance, yellowing resistance, and excellent adhesion to substrates or base coatings.

[0038] 3) Using specialized multi-stage curing equipment, UVA-LED quickly dries the product while effectively controlling the surface temperature; UVC excimer makes the product surface wrinkle-free and matte, increasing the smooth and silky feel; UVA conventional mercury lamp quickly cures the product, achieving the skin-feel effect of a coating.

[0039] 4) By using a variety of main connecting materials with different functions in combination with special equipment, a skin-like feel is achieved, making the product surface smooth, improving the touch experience, and enhancing the visual texture of the product surface.

[0040] 5) Elastic polyurethane acrylate UV resin provides excellent self-healing properties, soft touch, and scratch resistance. Silicone-modified polyurethane acrylate UV resin provides good stain and graffiti resistance, excellent wear resistance and fingerprint resistance, and excellent surface smoothness. Amine-modified polyester acrylate UV resin provides extremely high reactivity and curing speed, making it suitable for high-speed production lines, and has excellent weather resistance and yellowing resistance. Attached Figure Description

[0041] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0042] Figure 1 This is a physical illustration of the product obtained according to Embodiment 1 of the present invention;

[0043] Figures 2a-2c This is a flow chart of the curing process of the product obtained according to Embodiment 1 of the present invention;

[0044] Figure 3 A scanning electron microscope image of the surface of the product obtained according to Embodiment 1 of the present invention;

[0045] Figure 4 This is a scanning electron microscope image of the surface of the product prepared according to Comparative Example 8 of the present invention. Detailed Implementation

[0046] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.

[0047] Skin-friendliness refers to the sensory experience people get when their skin comes into contact with the outside world. It is mainly a combination of tactile and visual sensations. Therefore, skin-friendliness is mainly generated by surfaces with special structures (three-dimensional textures, unevenness) as well as surface friction, elasticity, and flexibility. When in contact with the skin, it feels smooth and soft, such as the silk-like feel. Skin-friendly coatings provide a skin-friendly touch, making products smoother, improving the tactile experience, and enhancing the visual texture of the product surface.

[0048] Example 1

[0049] This embodiment provides a skin-friendly UV coating, which mainly includes a base agent and a diluent.

[0050] The main agent is composed of the following components in parts by weight:

[0051]

[0052] Preferably, the diluent consists of the following components in parts by weight:

[0053] Ethyl acetate 75;

[0054] Butyl acetate 25.

[0055] The following is a detailed description of the function of each component in the above formula:

[0056] Photoinitiator 184 / 1173: The selected α-hydroxyalkyl phenyl ketone pyrolysis type free radical photoinitiator has excellent thermal stability and good resistance to yellowing. It is the main initiator for UV-cured varnishes with high requirements for yellowing resistance, and can also be used in combination with other photoinitiators in UV-cured paints.

[0057] Photoinitiator TPO / 819: This selected acylphosphine oxide pyrolysis type free radical photoinitiator exhibits high initiation activity, good overall performance, excellent thermal stability, and good storage stability, making it suitable for photocuring thick coatings. This type of photoinitiator is sensitive to sunlight or other short-wavelength visible light; therefore, care should be taken to avoid light during formulation preparation and storage.

[0058] Photoinitiator MBF: The selected hydrogen-abstracting free radical photoinitiator is a highly efficient liquid ultraviolet photoinitiator used to initiate the UV polymerization reaction of unsaturated prepolymer systems. Its resistance to yellowing is superior to most photoinitiators. It is used in ultraviolet curing systems that require good surface curing effect (stain resistance) and low color change after curing or aging.

[0059] Elastic polyurethane acrylate UV resin: The selected DIC elastic polyurethane acrylate UV resin is LUXYDIRZHU-1966. This example uses LUXYDIR ZHU-1966 with 2-3 functionality, which has excellent self-healing properties, soft touch, scratch resistance and other characteristics, and provides an excellent soft touch.

[0060] The structural formula of the dual-functionality polyurethane acrylate UV resin is as follows:

[0061]

[0062] The elastic polyurethane acrylate UV resin incorporates a large amount of polyether polyols (such as PTMG, molecular formula: HO-(CH2)4-O-(CH2)3-O-) into the existing conventional UV resin, providing long-chain flexibility and lowering the glass transition temperature (Tg). Compared with conventional polyurethane acrylate UV resins, it has a better soft touch. Here, the carbon-carbon double bond CH2=CH- represents the functionality involved in UV curing, and -CONH- represents the urethane segment. Of course, those skilled in the art will understand that this example is merely illustrative, and those skilled in the art can also use the 3-functional LUXYDIRZHU-1966.

[0063] Silicone-modified polyurethane acrylate UV resin: The selected silicone-modified polyurethane acrylate UV resin B-828 from Guangdong Boxin New Material Technology Co., Ltd. is preferred in this example. This resin has 5 functionalities, exhibiting good stain and graffiti resistance, excellent wear and fingerprint resistance, and a very smooth surface. The structural formula of commercially available polyurethane acrylate UV resins is as follows:

[0064]

[0065] As can be seen from the above, compared with conventional commercially available polyurethane acrylate UV resins, silicone-modified polyurethane acrylate UV resins introduce siloxanes (such as polydimethylsiloxane, -Si(CH3)2-O-) into the main chain or side chain of existing conventional UV resins, thereby improving weather resistance, hydrophobicity, and low surface energy. They also possess better stain and graffiti resistance, and excellent wear resistance and fingerprint resistance. Here, the carbon-carbon double bond CH2=CH- represents the functionality involved in UV curing, and -CONH- represents the urethane segment. The preferred 5-functionality polyurethane acrylate UV resin B-828 has a faster curing speed, and due to the formation of an ultra-dense cross-linked network by multiple (e.g., 5) acrylate double bonds, it significantly improves rigidity and deformation resistance, thereby increasing flexibility and adhesion.

[0066] Amine-modified polyester acrylate UV resin: The selected Castel polymer's dual-functional amine-modified polyester acrylate UV resin U-CURE9230 has the characteristics of low viscosity, high curing speed, and excellent flexibility, and is suitable for high solids content, low energy curing and other characteristics.

[0067] The structural formula of polyester acrylate UV resin is as follows:

[0068]

[0069] Amine-modified polyester acrylate UV resins are developed based on conventional UV resins by introducing amine groups (-NH2 or -NH-). Amine chain extenders (such as ethylenediamine EDA and isophorone diamine IPDA) introduce amino groups (-NH-), forming urea bonds (-NH-CO-). Amine-terminated polyols (such as amino polyethers) directly provide amine groups, enhancing reactivity, hardness, and weather resistance. Compared to conventional polyurethane acrylate UV resins, they possess extremely high reactivity and curing speed, making them suitable for rapid production lines (such as electronic packaging materials), and exhibiting excellent weather resistance and resistance to yellowing. R1-COO-R2 represents the polyester structure formed by the reaction of carboxyl and hydroxyl groups, while the carbon-carbon double bond CH2=CH- represents the functionality involved in UV curing.

[0070] Excimer UV resin: The selected excimer UV resin is irradiated with 254nm excimer light on the coating surface, causing it to shrink and form a microfolded structure. Due to the diffuse reflection generated by its folded structure, a matte effect is formed. The resulting coating film has a delicate, soft, elastic matte skin feel and excellent scratch resistance.

[0071] Pure acrylic resin: The selected pure acrylic resin oligomers possess good flexibility, excellent resistance to yellowing and solvents, and good adhesion to various substrates. However, their mechanical strength and hardness are very low, and due to the presence of ester bonds in the molecule, their acid and alkali resistance is poor. Therefore, in practical applications, pure acrylic resin is not used as the main resin, but rather as a co-reaction to improve the performance of UV-curable coatings, enhancing yellowing resistance, adhesion to substrates, and inter-coating adhesion.

[0072] The pure acrylic resin oligomer used in UV-curable coatings refers to acrylated polyacrylic resin, which is prepared by reacting a functionalized polyacrylate copolymer with glycidyl acrylate or hydroxyl acrylate to attach acryloyloxy groups to the side chains. For example, acrylated polyacrylate resin can be prepared by reacting a copolymer containing carboxyl groups in the side chains prepared by copolymerizing methyl acrylate, n-butyl acrylate, styrene, and acrylic acid under benzoyl peroxide initiation with glycidyl acrylate.

[0073] Due to its double-bonded structure, it can participate in the photocuring reaction, absorb excess energy to control the reaction activity, and prevent the paint film surface from becoming shiny due to excessive LED light exposure.

[0074] Due to its oligomer properties, it helps release stress during the UV curing process of the coating, forming uniform wrinkles and resulting in good gloss uniformity of the paint film. During the UV curing process, the molecular chains of the coating grow and cross-link rapidly, resulting in significant volume shrinkage in a short period of time. The molecular chains do not have enough time to relax and adjust, but the oligomers of pure acrylic resin help to slow down the shrinkage and release some of the stress, producing a uniform surface effect.

[0075]

[0076] Matting powder: It creates the desired roughness on the surface of the coating film, causing some refraction and diffuse reflection, thereby reducing the gloss of the coating film surface;

[0077] Wetting agents reduce the surface tension of the coating, reduce the coating's sensitivity to substrate contaminants, allow the coating to spread better on the substrate, and reduce the probability of paint film defects such as pinholes and craters.

[0078] Leveling agents: can effectively reduce the surface tension of the coating, improve leveling and uniformity, and promote the formation of a smooth, uniform coating film during the drying process.

[0079] The UV monomer HEMA (2-hydroxyethyl methacrylate) has the advantages of being soft and comfortable, and is an important class of soft monomers that can improve the flexibility of the coating film of UV-cured products.

[0080] The UV monomer HDDA: 1,6-hexanediol diacrylate is an important acrylate compound with good chemical stability and heat resistance. It can improve the hardness, abrasion resistance and chemical resistance of the coating film of UV-cured products, so that the final product has good performance.

[0081] UV monomer DPHA: dipentaerythritol hexaacrylate has good abrasion resistance, chemical resistance and excellent optical properties, and can be used to prepare coatings with high durability and high transparency.

[0082] The skin-friendly UV coatings described in the above embodiments were prepared by the following method:

[0083] 1) Preparation of photoinitiator dispersion

[0084] S1. In a dispersion container, ethyl acetate and butyl acetate are mixed in proportion and stirred to obtain a dispersion.

[0085] S2. Photoinitiator 184 / 1173, photoinitiator TPO / 819, and photoinitiator MBF are added slowly and sequentially to the dispersion obtained in step S1 during stirring. The mixture is dispersed until it is uniform. After the addition is complete, the stirring speed is increased and the mixture is dispersed for a certain period of time. The mixture is then filtered to obtain the photoinitiator dispersion.

[0086] 2) Preparation of skin-friendly UV coatings

[0087] S3. In a dispersion container, add elastic polyurethane acrylate UV resin, silicone-modified polyurethane acrylate UV resin, amine-modified polyester acrylate UV resin, excimer UV resin, and pure acrylic resin in sequence according to the proportion, and stir and disperse until uniform to obtain the first mixture.

[0088] S4. Slowly add the matting powder to the first mixture obtained in step S3 during the stirring process, disperse it until it is uniform, increase the stirring speed after the addition is complete, and continue to disperse for a certain period of time to obtain the second mixture.

[0089] S5. Wetting agent and leveling agent are slowly added to the second mixture in step S4 during the stirring process, and dispersed until uniform to obtain the third mixture;

[0090] S6. UV monomers HEMA, HDDA, and DPHA are slowly added to the third mixture in step S5 in sequence during stirring, and dispersed until uniform to obtain the fourth mixture.

[0091] S7. Slowly add propylene glycol methyl ether acetate solvent to the fourth mixture in step S6 and disperse until uniform to obtain the fifth mixture;

[0092] S8. Slowly add the photoinitiator dispersion obtained in step 1) to the fifth mixture in step S5. After the addition is complete, increase the stirring speed to disperse until uniform. Filter to obtain the skin-friendly UV coating.

[0093] The skin-friendly UV coating obtained in Example 1 was subjected to multi-stage UV curing using a multi-stage UV curing equipment. See [link to example]. Figures 2a-2c The multi-stage UV curing equipment includes a first-stage curing zone 10, a second-stage curing zone 20, and a third-stage curing zone 30. The first-stage curing zone 10 is equipped with a UVA-LED curing lamp 11, forming a high-wavelength curing zone 12. The second-stage curing zone 20 is equipped with a UVC excimer curing lamp 21, forming a low-wavelength curing zone 22. The third-stage curing zone 30 is equipped with a UVA mercury lamp curing lamp 31, whose wavelength is higher than that of the UVC excimer curing lamp 21 in the second-stage curing zone 20 but lower than that of the UVA-LED curing lamp 11 in the first-stage curing zone 10, forming a mid-wavelength curing effect shaping zone. This invention, through the combination of various functional binders and the use of specialized multi-stage curing equipment, provides a silk-like UV coating that is smooth, elastic, warm, soft, and extremely comfortable, like a baby's skin.

[0094] Specifically, see [link to relevant documentation] Figure 1 and Figures 2a-2c The skin-friendly UV coating 40 from Example 1 above is diluted to a suitable viscosity using a thinner and mixed evenly. It is then sprayed onto the paint 50 of the product workpiece and baked at 50°C for 6-10 minutes. Afterward, it undergoes multi-stage curing using a dedicated UV curing equipment for the skin-friendly UV coating 40. The curing energy of the UVA-LED curing lamp 11 in the first curing zone 10 is 4000-7000 mJ / cm². 2The curing energy of the UVC excimer curing lamp 21 in the second curing zone 20 is 170-270 mJ / cm². 2 The curing energy of the UVA mercury lamp curing lamp 31 in the three-stage curing zone 30 is 500-800 mJ / cm². 2 Light intensity is 80-150 mW / cm² 2 After cooling, physical property tests were conducted, and the results are shown in Table 1.

[0095] Figure 1 A physical image of the product obtained in Example 1 is shown; Figure 3 This is a scanning electron microscope (SEM) image of the surface of the product obtained in Example 1. Combined with... Figure 1 and Figure 3 As can be seen, the product obtained in Example 1 of the present invention is a skin-friendly UV coating. Figures 2a-2c After the curing process, the product surface has a soft, smooth, and delicate surface effect.

[0096] Comparative Example 1

[0097] The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, the elastic polyurethane acrylate UV resin LUXYDIR ZHU-1966 of DIC is replaced with an equal amount of conventional polyurethane acrylate UV resin LUXYDIR ZHU-2197.

[0098] All other conditions and ingredients are the same as in Example 1.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 replaces the organosilicon-modified polyurethane acrylate UV resin B-828 from Guangdong Boxin New Material Technology Co., Ltd. with an equal amount of conventional polyurethane acrylate UV resin B-328M.

[0101] All other conditions and ingredients are the same as in Example 1.

[0102] Comparative Example 3

[0103] The difference between Comparative Example 3 and Example 1 is that in Comparative Example 3, the amine-modified polyester acrylate UV resin U-CURE9230 of Castel Polymer was replaced with an equal amount of conventional polyester acrylate UV resin U-CURE9211.

[0104] All other conditions and ingredients are the same as in Example 1.

[0105] Comparative Example 4

[0106] The difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, all of the formulated amount of elastic polyurethane acrylate UV resin LUXYDIR ZHU-1966 was replaced with an equal amount of ethyl acetate solvent.

[0107] All other conditions and ingredients are the same as in Example 1.

[0108] Comparative Example 5

[0109] The difference between Comparative Example 5 and Example 1 is that in Comparative Example 5, all the formulated amounts of organosilicon-modified polyurethane acrylate UV resin B-828 were replaced with an equal amount of ethyl acetate solvent.

[0110] All other conditions and ingredients are the same as in Example 1.

[0111] Comparative Example 6

[0112] The difference between Comparative Example 6 and Example 1 is that in Comparative Example 6, all of the formulated amount of amine-modified polyester acrylate UV resin U-CURE 9230 was replaced with an equal amount of ethyl acetate solvent.

[0113] All other conditions and ingredients are the same as in Example 1.

[0114] Comparative Example 7

[0115] The difference between Comparative Example 7 and Example 1 is that in Comparative Example 7, all the pure acrylic resin WJ-468 in the formulation was replaced with an equal amount of ethyl acetate solvent.

[0116] All other conditions and ingredients are the same as in Example 1.

[0117] Comparative Example 8

[0118] The difference between Comparative Example 8 and Example 1 is that in Comparative Example 8, the exact amount of excimer UV resin L-6367-3 in the formulation is completely replaced with an equal amount of ethyl acetate solvent, which is a common traditional UV coating.

[0119] All other conditions and ingredients are the same as in Example 1.

[0120] Table 1: Physical and chemical performance test results of the product in Example 1 and commercially available conventional soft touch-coating products

[0121]

[0122]

[0123] As can be seen from Table 1, the product provided in Example 1 has a water contact angle of 108°, which is significantly higher than the 70° water contact angle of commercially available conventional products.

[0124] The product in Example 1 has significantly better oil resistance (stain resistance) than commercially available conventional products; its hardness (scratch resistance) is significantly higher than that of commercially available conventional products, and its scratch resistance is even better; its abrasion resistance is significantly better than that of commercially available conventional products in RCA paper tape friction, EF74 eraser friction, and CS-10F eraser friction tests; and its dynamic friction coefficient of 1.2 is significantly better than that of commercially available conventional products of 3.5, and its smoothness is better.

[0125] The anti-tack property ensures that the product remains tack-free even after long-term use, significantly outperforming commercially available conventional products. The coating provided by this invention exhibits superior resistance to stains, scratches, abrasion, and tack, while also providing a skin-like feel (e.g., a silk-like texture), resulting in a smooth surface, improved tactile experience, and enhanced visual texture.

[0126] Table 2: Physicochemical performance test results of Example 1 and Comparative Examples 1-3

[0127]

[0128]

[0129] Referring to Table 2, the skin-friendly UV coatings obtained in Example 1 and Comparative Example 1 were subjected to a scratch resistance test using a 318 hardness bar. Table 2 shows that the skin-friendly UV coating prepared in Example 1 showed no scratches, while the skin-friendly UV coating prepared in Comparative Example 1 showed slight scratches; this indicates that the elastic polyurethane acrylate UV resin used in Example 1 has superior flexibility and self-healing properties compared to conventional UV resins.

[0130] The skin-friendly UV coatings obtained in Example 1 and Comparative Example 2 were subjected to stain resistance tests using an oil-based pen. Table 2 shows that the skin-friendly UV coating prepared in Example 1 left no residue, while the skin-friendly UV coating prepared in Comparative Example 2 left residue. This indicates that the silicone-modified polyurethane acrylate UV resin used in Example 1 has better stain resistance and anti-graffiti effect than conventional UV resins.

[0131] The skin-friendly UV coatings obtained in Example 1 and Comparative Example 3 were tested using a pencil hardness tester and UV aging tests. Table 2 shows that the skin-friendly UV coating obtained in Example 1 showed no marks at hardness 2H and slight marks at hardness 3H, and the coating appearance remained unchanged after 300 hours of UV aging. In contrast, the skin-friendly UV coating obtained in Comparative Example 3 showed no marks at hardness 1H and slight marks at hardness 2H, and the coating appearance turned slightly yellow after UV aging. This indicates that the amine-modified polyester acrylate UV resin used in Example 1 has stronger reactivity and superior hardness and weather resistance compared to conventional UV resins.

[0132] Table 3: Physical and chemical properties and workability test results of Example 1 and Comparative Examples 4-8

[0133]

[0134]

[0135] The skin-friendly UV coatings obtained from Example 1, Comparative Examples 4, and 8 were subjected to RPC value testing using a roughness meter. Table 3 shows that the RPC value of Comparative Example 4 (150) is much lower than that of Example 1, and the RPC value of Comparative Example 8 (80) is also much lower than that of Example 1. Because Comparative Example 4 did not add elastic polyurethane acrylate UV resin, the surface smoothness of the coating decreased, resulting in a lower RPC value. Comparative Example 8 did not add excimer UV resin, so the coating could not form wrinkles, and the surface was rough and uneven. Figure 4 The traditional coating product surface scanning electron microscope image shows a lower RPC value, which is a characterization of smoothness. However, in Example 1, the combination of elastic polyurethane acrylate UV resin and excimer UV resin increases the smoothness of the coating surface wrinkles, resulting in a significant improvement in the smoothness of the coating surface. The RPC value is much higher than the measured values ​​of Comparative Example 4 and Comparative Example 8.

[0136] The skin-friendly UV coatings obtained in Example 1, Comparative Examples 5 and 8 were subjected to RSK value measurement using a roughness meter. Table 3 shows that the RSK value of Comparative Example 5 (0.6) is much larger than that of Example 1, and the RSK value of Comparative Example 8 (0.8) is also much larger than that of Example 1. Because Comparative Example 5 did not contain silicone-modified polyurethane acrylate UV resin, the coating surface exhibited decreased stain and fingerprint resistance, resulting in an increased RSK value. In Comparative Example 8, the absence of excimer UV resin prevented the formation of wrinkles in the coating, resulting in a rough and uneven surface. Figure 4 The traditional coating products in the traditional SEM images show that their stain resistance and fingerprint resistance are worse, and stains are more likely to remain on the rough and irregular coating surface, resulting in a higher RSK value. However, in Example 1, the combination of silicone-modified polyurethane acrylate UV resin and excimer UV resin increases the stain resistance on the wrinkled surface of the coating, which greatly improves the stain resistance and fingerprint resistance of the coating surface, and the RSK value is much lower than the measured values ​​of Comparative Examples 5 and 8.

[0137] The skin-friendly UV coatings obtained in Example 1, Comparative Examples 6 and 8 were tested by large-area spraying. They were baked at 50°C for 6-10 minutes and then cured in multiple stages using a dedicated skin-friendly UV coating curing device. Table 3 shows that Comparative Example 6 exhibited ice-flower patterns during large-area spraying, while Example 1 showed no abnormalities. Comparative Example 8 showed no abnormalities in appearance but lacked a tactile feel. Because Comparative Example 6 did not contain amine-modified polyurethane acrylate UV resin, its reactivity and curing speed were reduced, resulting in poor pre-curing under the LED lamps and significant shrinkage and ice-flower patterns under the excimer lamps. In contrast, Example 1 combined amine-modified polyurethane acrylate UV resin with excimer UV resin, allowing for rapid pre-curing of the coating bottom under the LED lamps. After excimer lamp irradiation, the shrinkage produced uniform wrinkles, resulting in a uniform and normal appearance.

[0138] The skin-friendly UV coatings obtained in Example 1, Comparative Examples 7 and 8 were tested by large-area spraying, baked at 50℃ for 6-10 minutes, and then cured in multiple stages using a dedicated skin-friendly UV coating curing equipment. Table 3 shows that bright spots appeared in the large-area spraying of Comparative Example 7, while the spraying effect of Example 1 was normal. The large-area spraying of Comparative Example 8 showed no abnormalities in appearance but lacked a tactile feel. Because Comparative Example 7 did not contain pure acrylic resin, its high reactivity led to unstable LED pre-curing and excessive local irradiation, resulting in bright spots. In contrast, the combination of pure acrylic resin and excimer UV resin in Example 1 effectively controlled reactivity, resulting in uniform gloss and a smooth, normal appearance.

[0139] The skin-friendly UV coating and its preparation method provided by the embodiments of the present invention have at least one or a portion of the following advantages:

[0140] 1) This skin-friendly UV coating uses a variety of different functional resins as the main binders, resulting in a soft, smooth, and delicate surface effect;

[0141] 2) By combining various functional modified UV resins, compared with conventional polyurethane acrylate UV resins, it also has the functions of scratch resistance, fingerprint resistance, wear resistance, yellowing resistance, and excellent adhesion to substrates or base coatings.

[0142] 3) Using specialized multi-stage curing equipment, UVA-LED quickly dries the product while effectively controlling the surface temperature; UVC excimer makes the product surface wrinkle-free and matte, increasing the smooth and silky feel; UVA conventional mercury lamp quickly cures the product, achieving the skin-feel effect of a coating.

[0143] 4) By using a variety of main connecting materials with different functions in conjunction with specialized equipment, a skin-like feel is achieved, making the product surface smooth, improving the tactile experience, and enhancing the visual texture of the product surface (such as aesthetic appeal (e.g., a noble and elegant, visually warm and comfortable feeling)).

[0144] 5) Elastic polyurethane acrylate UV resin provides excellent self-healing properties, soft touch, and scratch resistance. Silicone-modified polyurethane acrylate UV resin provides good stain and graffiti resistance, excellent wear resistance and fingerprint resistance, and excellent surface smoothness. Amine-modified polyester acrylate UV resin provides extremely high reactivity and curing speed, making it suitable for high-speed production lines, and has excellent weather resistance and yellowing resistance.

[0145] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.

Claims

1. A skin-friendly UV coating, characterized in that, the skin-friendly UV coating comprises a main agent and a diluent, and the main agent is prepared from the following raw materials in parts by weight:

2. The skin-friendly UV coating according to claim 1, characterized in that, the α-hydroxy alkyl phenone type cleavage radical photoinitiator is selected from Omnirad 184 and / or Omnirad 1173 of IGM.

3. The skin-friendly UV coating according to claim 1, characterized in that, the acyl phosphine oxide cleavage radical photoinitiator is selected from Omnirad TPO and / or Omnirad 819.

4. The skin-friendly UV coating according to claim 1, characterized in that, the hydrogen abstraction type radical photoinitiator is selected from Omnirad MBF.

5. The skin-friendly UV coating according to claim 1, characterized in that, the elastic polyurethane acrylate UV resin is selected from LUXYDIR ZHU-1966 with a functionality of 2-3.

6. The skin-friendly UV coating according to claim 1, characterized in that, the silicone-modified polyurethane acrylate UV resin is selected from B-828 with a functionality of 5.

7. The skin-friendly UV coating according to claim 1, characterized in that, the amine-modified polyester acrylate UV resin is selected from U-CURE 9230 with a functionality of 2.

8. The skin-friendly UV coating according to claim 1, characterized in that, the excimer UV resin is selected from one or more of L-6367-2, L-6367-3, W4480L, and W4485S.

9. The skin-friendly UV coating according to claim 1, characterized in that, the pure acrylic resin is selected from WJ-468; the matting powder is selected from E-1011; the wetting agent is selected from TEGO Rad 2200N; the leveling agent is selected from TEGO Flow ATF2.

10. A preparation method of the skin-friendly UV coating according to any one of claims 1-9, comprising the following steps: 1) Preparation of a photoinitiator dispersion S1. In a dispersion container, mix the two solvents of ethyl acetate and butyl acetate in proportion, and stir and disperse to obtain a dispersion; S2. Slowly add the α-hydroxy alkyl phenone type cleavage radical photoinitiator 184 / 1173, the acyl phosphine oxide cleavage radical photoinitiator photoinitiator TPO / 819, and the hydrogen abstraction type radical photoinitiator MBF into the dispersion in turn during stirring until evenly dispersed. After adding, increase the stirring speed and continue to disperse for a predetermined time. Filter to obtain a photoinitiator dispersion; 2) Preparation of a skin-friendly UV coating S3. In a dispersion container, slowly add the elastic polyurethane acrylate UV resin, the silicone-modified polyurethane acrylate UV resin, the amine-modified polyester acrylate UV resin, the excimer UV resin, and the pure acrylic resin into the photoinitiator dispersion in turn in proportion, and stir and disperse until evenly dispersed to obtain a first mixture; S4, slowly add the matting powder to the first mixture during stirring, disperse to be uniform, increase the stirring speed after adding, continue to disperse to obtain a second mixture; S5, add the wetting agent and the leveling agent to the second mixture during stirring, disperse to be uniform to obtain a third mixture; S6, add the UV monomer HEMA, the UV monomer HDDA and the UV monomer DPHA to the third mixture during stirring, disperse to be uniform to obtain a fourth mixture; S7, slowly add the propylene glycol methyl ether acetate solvent to the fourth mixture, disperse to be uniform to obtain a fifth mixture; S8, slowly add the photoinitiator dispersion liquid prepared in the first step to the fifth mixture, increase the stirring speed after adding, disperse to be uniform, filter to obtain the skin-friendly UV coating.

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