An excimer coating and its preparation process

Abstract

This invention provides an excimer coating and its preparation process. The raw materials of the excimer coating, by mass percentage, include the following components: 30-60% film-forming substance; 3-10% elastic microparticles; 2-5% photoinitiator; 0.5-2.0% wetting agent; 0.5-1.5% dispersant; 0.5-5% matting agent; and 20-40% solvent. The film-forming substance is a polyurethane acrylate resin with a multifunctional microphase structure regulated. This invention improves the crosslinking density and structural compactness of the system by using polyurethane acrylate resin modified with multifunctional microparticles. Simultaneously, it introduces elastic microspheres of specific particle size and synergistic additives to achieve a balanced optimization of coating feel, matting effect, and mechanical properties. This coating maintains excellent tactile feel while significantly improving adhesion, hardness, and abrasion resistance, and retains good interfacial stability under thermal shock and high temperature and humidity conditions, thus meeting the application requirements of high-end surface coating fields.

Description

Technical Field

[0001] This invention relates to the field of UV coating technology, and in particular to an excimer coating and its preparation process. Background Technology

[0002] In the fields of electronic devices, decorative materials, and functional films, ultraviolet (UV) curing coatings are widely used due to their fast curing speed, low energy consumption, and low VOC emissions. Among them, UV curing technology based on excimer light sources (such as 172 nm wavelength excimer lamps) is gradually becoming an important development direction for high-end surface treatment due to its higher energy, shallower penetration depth, and excellent surface curing ability. It is especially suitable for substrates with extremely high surface performance requirements, such as plastic films, engineering plastics, and composite materials.

[0003] However, existing excimer UV coating systems still face numerous technical bottlenecks in practical applications. On the one hand, traditional UV coatings often use low-functionality or linear acrylic resins with limited crosslinking density, resulting in insufficient hardness and abrasion resistance of the cured coating. This leads to problems such as wear and chipping, especially at the edges, making it difficult to meet the demands for high durability. On the other hand, with the increasing complexity of application environments, the adhesion stability of coatings under harsh conditions such as thermal shock and temperature and humidity cycling has become a key indicator. However, existing systems, due to insufficient interfacial compatibility and high internal stress, are prone to failure phenomena such as decreased adhesion, cracking, and even peeling.

[0004] Furthermore, to improve the tactile properties of the coating, some technical solutions introduce silicone or polyurethane-based feel-enhancing agents. However, their dispersion stability in the system and compatibility with the base resin are poor, often sacrificing the mechanical properties and surface uniformity of the coating while improving the feel. Meanwhile, although the introduction of matting agents can reduce surface gloss, the particle size and distribution of conventional inorganic matting fillers are not well controlled, easily leading to increased coating roughness, which further affects abrasion resistance and adhesion.

[0005] Therefore, achieving a synergistic optimization of high hardness, high adhesion, excellent abrasion resistance, and good feel in excimer UV curing systems, especially maintaining stable performance under complex environmental conditions, has become a pressing technical problem in this field. To address these issues, developing a novel excimer UV coating system that combines high crosslinking density, good interfacial compatibility, and the synergistic effect of multifunctional additives is of great significance for improving the overall performance of coatings and expanding their application range. Summary of the Invention

[0006] Objective of the Invention: The objective of this invention is to address the problems of insufficient hardness, poor abrasion resistance, easy edge wear, and poor adhesion stability under thermal shock and high temperature and humidity conditions in existing excimer UV coatings, by providing an excimer coating and its preparation process. By employing polyurethane acrylate resin modified with multifunctional microparticles, the crosslinking density and structural compactness of the system are improved; simultaneously, elastic microspheres of specific particle size and synergistic additives are introduced to achieve a balanced optimization of coating feel, matte finish, and mechanical properties. This coating significantly improves adhesion, hardness, and abrasion resistance while maintaining excellent tactile feel, and retains good interfacial stability under thermal shock and high temperature and humidity conditions, thus meeting the application requirements of high-end surface coating fields.

[0007] The technical solution of this invention: In a first aspect, the present invention provides an excimer coating; the raw materials of the excimer coating, by weight percentage, comprise the following components: Film-forming substances: 30-60%; Elastic microparticles 3-10%; Photoinitiator 2-5%; Wetting agent 0.5-2.0%; Dispersant 0.5-1.5%; Matting agent 0.5-5%; Solvent 20-40%; The film-forming substance is a polyurethane acrylate resin with a multifunctional microphase structure.

[0008] Furthermore, the multifunctional groups of the polyurethane acrylate resin with multifunctional microphase structure regulation refer to 5-6 functional groups.

[0009] In some embodiments, the method for preparing the film-forming substance includes the following steps: S1: Add polyester polyol and polyether polyol to the reactor, then add diisocyanate and catalyst, heat to react, and obtain prepolymer; S2: Add a polyhydroxy compound and continue heating to react, resulting in a branched structure; S3: Add microparticles, and then perform high-speed shearing under heating conditions to form a microphase structure; S4: After cooling, add hydroxy acrylate and polymerization inhibitor, and continue the reaction. After the reaction is completed, a polyurethane acrylate resin with a multifunctional microphase structure is obtained.

[0010] In some embodiments, the mass ratio of the added polyester polyol, polyether polyol, diisocyanate, polyhydroxy compound, and microparticles is 30-50:10-20:20-35:5-15:1-8.

[0011] In some embodiments, the polyhydroxy compound is selected from one or more combinations of trimethylolpropane or pentaerythritol.

[0012] In some embodiments, the microparticles are selected from one or more combinations of nano-SiO2 or organosilicon microparticles.

[0013] In some embodiments, the elastic microparticles are selected from one or a combination of two of silicone elastomer microspheres or polyurethane elastic microspheres.

[0014] In some embodiments, the photoinitiator is selected from one or more combinations of α-hydroxy ketones, acylphosphine oxides, and amino ketones; further, the photoinitiator is selected from one or more combinations of 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methylphenylacetone, BAPO, and 2-methyl-1-(4-methylthiophenyl)-2-morpholinoacetone.

[0015] In some embodiments, the wetting agent is selected from one or more combinations of silicone wetting agents, fluorocarbon wetting agents, or polyether modified surfactants.

[0016] In some embodiments, the dispersant is selected from one or more combinations of polyacrylate, polyester, or block copolymer dispersants.

[0017] In some embodiments, the matting agent is selected from one or more combinations of silica, wax powder, or polymeric matting particles; further, the matting agent is selected from one or more combinations of amorphous SiO2, fumed SiO2, polyamide wax powder, polyethylene wax micropowder, and PMMA microspheres.

[0018] In some embodiments, the solvent is selected from one or more combinations of ethyl acetate, butyl acetate, methyl isobutyl ketone, acetone, diacetone alcohol, and isopropanol.

[0019] In a second aspect, the present invention provides a method for preparing the excimer coating, specifically comprising the following steps: (1) The film-forming substance, dispersant and part of the solvent are added to a mixing container and pre-dispersed under medium-speed stirring to obtain the first mixed system; (2) Add elastic microparticles, wetting agent and part of solvent to the first mixture system, and disperse it under high-speed dispersion conditions to obtain the second mixture system; (3) After the photoinitiator is dissolved in the solvent to form a transparent solution, it is added to the second mixing system and dispersed under medium-speed stirring. The viscosity of the system is adjusted by adding the remaining solvent to obtain the finished excimer coating.

[0020] In some embodiments, the medium-speed stirring speed in step (1) is 400-800 rpm, and the dispersion time is 5-15 minutes.

[0021] In some implementations, the high-speed dispersion rotation speed in step (2) is 800-1500 rpm and the dispersion time is 15-40 minutes.

[0022] In some implementations, the dispersion speed in step (3) is 400-800 rpm and the dispersion time is 15-40 minutes.

[0023] In some embodiments, the viscosity of the finished excimer coating product described in step (3) is 50-70 KU.

[0024] Beneficial effects: The excimer coating provided by this invention, through the synergistic design of a polyurethane acrylate film-forming system with multifunctional microphase structure regulation and elastomer microparticle tactile materials, significantly improves the overall mechanical properties of the coating while maintaining excellent tactile feel and low gloss. Test results show that the coating of this invention exhibits a relatively uniform film thickness distribution in both large areas and edge regions, effectively reducing wear problems caused by stress concentration at corners. In abrasion resistance tests, the number of cycles is significantly increased, demonstrating superior abrasion resistance. Simultaneously, adhesion test results show that high levels are achieved in different areas (large areas and high-gloss edges), and the coating remains stable after thermal shock and temperature and humidity environments, indicating that its interfacial bonding strength and structural stability are significantly better than existing technologies. Furthermore, by optimizing the matting system and wetting and dispersion system, this invention achieves a uniform and delicate coating surface without obvious defects, achieving low gloss without sacrificing mechanical properties. In summary, this invention effectively solves the technical problem of the difficulty in simultaneously achieving hardness, abrasion resistance, adhesion, and tactile feel in existing excimer UV coatings, and has promising application prospects. Detailed Implementation

[0025] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0026] Unless otherwise specified, all chemical reagents used in this invention are commercially available analytical grade reagents.

[0027] Sodium polyacrylate was purchased from Qingdao Shouke New Materials Co., Ltd. The preparation method of organosilicon elastic microspheres is as follows: (1) 20g of vinyl-terminated dimethyl silicone oil (Mw = 1.9 ± 0.1 × 10⁻⁶) 4(Vinyl content 0.4±0.1%wt, commercially available) and 80g of hydrogen-containing silicone oil (Mw=2.1±0.1×10) 4 Mix the following ingredients (containing 0.07±0.01%wt hydrogen, commercially available) and then add the calculated amount of chloroplatinic acid (based on Pt accounting for 10ppm of the mixture), and mix thoroughly. (2) Add 4g of polyoxyethylene sorbitan fatty acid ester (purchased from Sinopharm, Tween 20) to 200g of water to prepare a solution; (3) The mixture obtained in step (1) is mixed with the solution in step (2) and homogenized to form an emulsion. The mixture is reacted at 50°C for 4 hours. After drying the emulsion, it is ground to obtain organosilicon elastic microspheres with a particle size of about 5 μm.

[0028] Example 1 (1) Add 45 parts of film-forming material, 1 part of dispersant (sodium polyacrylate, Dow Chemical, brand ACUSOL 445NPolymer), 1 part of matting agent (amorphous silica with a particle size of 1.5 μm) and 6 parts of solvent (EA / BA / MIBK volume ratio 1:1:1) into a mixing container, stir at 600 rpm for 6 minutes to pre-disperse and obtain the first mixed system; (2) Add 6 parts of elastic microparticles (organosilicon elastic microspheres), 1 part of wetting agent (OT-75) and 4 parts of solvent (EA / BA / MIBK volume ratio 1:1:1) to the first mixed system, and disperse at 1000 rpm for 20 min to obtain the second mixed system; (3) Dissolve 3.5 parts of photoinitiator (1173 / TPO mass ratio 1:1) in 4 parts of solvent (EA / BA / MIBK volume ratio 1:1:1) to form a transparent solution, then add it to the second mixing system. Continue to disperse at 600 rpm for 30 minutes until clear and transparent. Adjust the viscosity of the system to 60±2KU by adding 27 parts of solvent to obtain the finished excimer coating.

[0029] The preparation steps of the film-forming substance are as follows: S1: Add 30 parts by weight of polyester polyol (Steppen Chemical, PC-1011-55) and 10 parts by weight of polyether polyol (purchased from Dow Chemical, brand name VORANOL) to the reactor. TM Add 2000 LM), then add 25 parts of diisocyanate and 0.1 parts of catalyst dibutyltin dilaurate, heat at 75°C for 2 hours to obtain the prepolymer; S2: Add 10 parts of pentaerythritol, and continue heating the reaction at 75°C for 2 hours to obtain the branched structure; S3: Add 5 parts of nano-SiO2, and after adding, heat at 70℃ and shear at 3000 rpm for 60 min to form a microphase structure; S4: After cooling to 50℃, add 20 parts HEMA and 0.05 parts hydroquinone, and continue the reaction for 2 hours. After the reaction is completed, a polyurethane acrylate resin with a multifunctional microphase structure is obtained, which is the film-forming substance.

[0030] Example 2 The preparation steps of Example 2 are basically the same as those of Example 1, except that the mass fractions of the film-forming substance added are 55 parts, the mass fractions of the elastic microparticles added are 4 parts, and the mass fractions of the photoinitiator added are 4 parts. All other steps and amounts are the same.

[0031] Example 3 The preparation steps of Example 3 are basically the same as those of Example 1, except that the mass fractions of the film-forming substance added are 40 parts, the mass fractions of the elastic microparticles added are 9 parts, and the mass fractions of the matting agent added are 4 parts. All other steps and amounts are the same.

[0032] Comparative Example 1 The preparation steps of Comparative Example 1 are basically the same as those of Example 1, except that the preparation steps of the film-forming substance are as follows: S1: By mass, add 30 parts of polyester polyol and 10 parts of polyether polyol to the reactor, then add 25 parts of diisocyanate and 0.1 parts of catalyst dibutyltin dilaurate, heat at 75°C for 2 hours to obtain the prepolymer; S2: After cooling to 50℃, add 20 parts HEMA and 0.05 parts hydroquinone, and continue the reaction for 2 hours. After the reaction is completed, a polyurethane acrylate resin with a multifunctional microphase structure is obtained, which is the film-forming substance.

[0033] Comparative Example 2 The preparation steps of Comparative Example 2 are basically the same as those of Example 1, except that the preparation steps of the film-forming substance are as follows: S1: By mass, add 30 parts of polyester polyol and 10 parts of polyether polyol to the reactor, then add 25 parts of diisocyanate and 0.1 parts of catalyst dibutyltin dilaurate, heat at 75°C for 2 hours to obtain the prepolymer; S2: Add 10 parts of pentaerythritol, and continue heating the reaction at 75°C for 2 hours to obtain the branched structure; S3: Microphase structure was formed by high-speed shearing at 3000 rpm for 60 minutes under heating conditions at 70℃; S4: After cooling to 50℃, add 20 parts HEMA and 0.05 parts hydroquinone, and continue the reaction for 2 hours. After the reaction is completed, a polyurethane acrylate resin with a multifunctional microphase structure is obtained, which is the film-forming substance.

[0034] Comparative Example 3 The preparation steps of Comparative Example 3 are basically the same as those of Example 1, except that the number of elastic microparticles added in step (2) is 0.

[0035] Comparative Example 4 The preparation steps of Comparative Example 4 are basically the same as those of Example 1, except that the number of dispersants added in step (1) is 0 and the number of wetting agents added in step (2) is 0.

[0036] Performance testing The excimer coating prepared above was applied to the surface of a PET film substrate to form a single-layer wet film coating with a thickness of approximately 50 μm. A 172 nm excimer lamp was then used at 1500 mJ / cm². 2 Irradiate for 15 seconds under the given conditions, then apply 3000 mJ / cm 2 Irradiate for 15 seconds under the given conditions, then let stand for 24 hours to obtain the layer.

[0037] The above materials were subjected to the following tests: 1. Adhesion test: Using a 1.0mm intersecting grid, with a blade angle between 15-30°, cut through the coating to the substrate, making 11 horizontal and 11 vertical cuts to form 100 grids. Cut at the four corners, faces, and sidewalls. Use 3M 600 tape, placing the center of the tape on the grid. Rub the tape vigorously with an eraser for 90±10 seconds, then quickly pull it up parallel to the grid at a 180° angle. Inspect the grid using a magnifying glass. Evaluation criteria: 0 is the best, 5 is the worst.

[0038] 2. Hardness test: Reference standard: ASTM D3363; Pencil type: Mitsubishi (6B-5B-4B-3B-2B-B-HB-FH-2H-3H-4H-5H-6H). First, hold the pencil at a 90-degree angle and sand it on 400-grit sandpaper until the lead has a smooth, flat, round cross-section when viewed from the front. Place the product on a horizontal and stable surface and start testing with the hardest pencil. Fix the pencil on a 750g hardness tester, making it at a 45-degree angle to the paint surface, with a lead length of 5-6mm and a sliding length of 6.5cm. Repeat this process until it can no longer scratch the surface. Record the pencil type.

[0039] 3. Edge wear test Using a Ф2.0 steel rod, a 500g weight was applied at a speed of 30 cycles / minute, a test distance of 50mm, and the test sample was set at 45°. A total of 15 cycles were performed, with observation every 5 cycles, repeating until the paint at the edge and corner was damaged. The number of cycles required for noticeable edge and corner damage was recorded; a negative number indicates no wear.

[0040] 4. Thermal shock test Place the sample at the lowest temperature (-40℃) for 1 hour, then place it at a high temperature of 60℃ for 1 hour. Repeat this low-temperature and high-temperature environmental treatment for 48 hours per cycle, and then perform an adhesion test.

[0041] The test results are shown in Table 1.

[0042] Table 1 Test Data The embodiment maintained a hardness of 0 or near 0 on its large surfaces, corners, and sidewalls, and remained stable after thermal shock, while the comparative example showed a significant decrease in hardness at the corners and after impact, indicating that the interfacial bonding of the present invention is more stable under complex stress environments. The hardness of the embodiment was significantly higher than that of comparative example 1, proving that the high-functionality resin brings a higher crosslinking density. The embodiment showed no significant damage after 15 cycles, while the comparative examples generally showed damage within 10 cycles, indicating that the technical solution of combining microphase structure and elastic microparticles provided by the present invention can significantly improve edge resistance to damage.

[0043] Overall, it can be seen that the embodiments of the present invention are superior to the comparative examples in terms of adhesion, hardness and edge abrasion resistance. In particular, they maintain good performance after thermal shock, indicating that the synergistic effect of multifunctional resin, microphase structure and elastic microparticles significantly improves the structural stability and resistance to damage of the coating.

[0044] The present invention can also be implemented in various other ways. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. An excimer coating, characterized in that, The raw materials of the excimer coating, by weight percentage, include the following components: Film-forming substances: 30-60%; Elastic microparticles 3-10%; Photoinitiator 2-5%; Wetting agent 0.5-2.0%; Dispersant 0.5-1.5%; Matting agent 0.5-5%; Solvent 20-40%; The film-forming substance is a polyurethane acrylate resin with a multifunctional microphase structure.

2. The excimer coating according to claim 1, characterized in that, The polyurethane acrylate resin with multifunctional microphase structure regulated by the multifunctional group has 5-6 functional groups.

3. The excimer coating according to claim 1, characterized in that, The preparation method of the film-forming substance includes the following steps: S1: Add polyester polyol and polyether polyol to the reactor, then add diisocyanate and catalyst, heat to react, and obtain prepolymer; S2: Add a polyhydroxy compound and continue heating to react, resulting in a branched structure; S3: Add microparticles, and then perform high-speed shearing under heating conditions to form a microphase structure; S4: After cooling, add hydroxy acrylate and polymerization inhibitor, and continue the reaction. After the reaction is completed, a polyurethane acrylate resin with a multifunctional microphase structure is obtained.

4. The excimer coating according to claim 3, characterized in that, The mass ratio of the added polyester polyol, polyether polyol, diisocyanate, polyhydroxy compound, and microparticles is 30-50:10-20:20-35:5-15:1-8.

5. The excimer coating according to claim 3, characterized in that, The polyhydroxy compound is selected from one or more combinations of trimethylolpropane or pentaerythritol.

6. The excimer coating according to claim 3, characterized in that, The microparticles are selected from one or more combinations of nano-SiO2 or organosilicon microparticles.

7. The excimer coating according to claim 1, characterized in that, The elastic microparticles are selected from one or a combination of two of silicone elastomer microspheres or polyurethane elastic microspheres.

8. The excimer coating according to claim 1, characterized in that, The photoinitiator is selected from one or more combinations of α-hydroxy ketones, acylphosphine oxides, and amino ketones; the wetting agent is selected from one or more combinations of organosilicon wetting agents, fluorocarbon wetting agents, or polyether-modified surfactants; the dispersant is selected from one or more combinations of polyacrylates, polyesters, or block copolymer dispersants; the matting agent is selected from one or more combinations of silica, wax powder, or polymeric matting particles; and the solvent is selected from one or more combinations of ethyl acetate, butyl acetate, methyl isobutyl ketone, acetone, diacetone alcohol, and isopropanol.

9. The preparation process of the excimer coating according to any one of claims 1-8, characterized in that, Includes the following steps: (1) The film-forming substance, dispersant and part of the solvent are added to a mixing container and pre-dispersed under medium-speed stirring to obtain the first mixed system; (2) Add elastic microparticles, wetting agent and part of solvent to the first mixture system, and disperse it under high-speed dispersion conditions to obtain the second mixture system; (3) After the photoinitiator is dissolved in the solvent to form a transparent solution, it is added to the second mixing system and dispersed under medium-speed stirring. The viscosity of the system is adjusted by adding the remaining solvent to obtain the finished excimer coating.

10. The preparation process of the excimer coating according to claim 9, characterized in that, The medium-speed stirring speed in step (1) is 400-800 rpm, and the dispersion time is 5-15 minutes; the high-speed dispersion speed in step (2) is 800-1500 rpm, and the dispersion time is 15-40 minutes; the dispersion speed in step (3) is 400-800 rpm, and the dispersion time is 15-40 minutes.

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