Excimer uv coating and method of making and using same

Abstract

The application provides an excimer UV coating and a preparation method and application thereof, relates to the technical field of excimer UV coatings, and the water-based excimer UV coating comprises the following components in mass ratio: 2-functional water-based polyurethane acrylate resin 20%-30%, multi-functional water-based polyurethane acrylate resin 25%-35%, UV monomer 35%-40%, photoinitiator 3%-6%, and auxiliary agent 0.5%-1%. The excimer UV coating has excellent matte skin effect and adhesion.

Description

Technical Field

[0001] This invention relates to the field of excimer UV coating technology, specifically to excimer UV coatings, their preparation methods, and applications. Background Technology

[0002] Excimer UV coating is a new type of environmentally friendly coating based on 254nm excimer ultraviolet lamp curing. It uses deep ultraviolet light with an extremely short wavelength of 254nm and extremely weak penetration to first cure the outermost layer of the coating, causing it to shrink instantly to form an extremely thin, wrinkled cured film. Then, a UV lamp such as a mercury lamp or LED lamp is used to thoroughly cure the lower layer, ultimately forming a smooth coating with nanoscale micro-wrinkles on the surface, thus achieving an ultimate matte finish and excellent tactile feel.

[0003] However, existing excimer UV coatings require the addition of organic and inorganic fillers in conjunction with the aforementioned curing process to achieve an ultimate matte finish. The added filler particles themselves lack adhesive properties. When fillers are added to the coating, some of the resin that should directly contact the substrate surface is replaced by the filler. Furthermore, the presence of fillers consumes polar groups in the coating resin that should form chemical bonds with the substrate surface. As a result, while the coating with filler particles has a good matte finish, its adhesion to the substrate is poor, affecting the coating's lifespan. In addition, the addition of fillers negatively impacts the UV coating's curing speed and surface abrasion resistance. Therefore, providing an excimer UV coating with superior matte finish, adhesion, and abrasion resistance has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides an excimer UV coating, its preparation method, and its application, solving the technical problem that existing excimer UV coatings cannot simultaneously achieve a matte finish, adhesion, and abrasion resistance.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] The first aspect of this invention provides an aqueous excimer UV coating comprising the following components in the following mass ratio:

[0007] 20%-30% of waterborne polyurethane acrylate resin

[0008] Multifunctional waterborne polyurethane acrylate resin 25%-35%,

[0009] UV monomers 35%-40%,

[0010] Photoinitiator 3%-6%,

[0011] Additives: 0.5%-1%.

[0012] Secondly, a method for preparing the aforementioned waterborne excimer UV coating is provided, wherein the difunctional waterborne polyurethane acrylate resin, the polyfunctional waterborne polyurethane acrylate resin, the UV monomer, the photoinitiator, and the additives are weighed and mixed according to the mass ratio, and then stirred and dispersed at 35-45°C for 1-2 hours to obtain the waterborne excimer UV coating.

[0013] Thirdly, an article is provided, comprising a substrate and a coating applied to the substrate, wherein the coating is formed by applying and curing the water-based excimer UV coating.

[0014] Compared with existing technologies, it has the following beneficial effects:

[0015] This invention provides a waterborne excimer UV coating comprising a difunctional waterborne polyurethane acrylate resin and a polyfunctional waterborne polyurethane acrylate resin. In this invention, the ratio of the difunctional and polyfunctional waterborne polyurethane acrylate resins is crucial. During UV curing, an appropriate amount of difunctional resin can effectively reduce internal stress and improve adhesion, while an appropriate amount of polyfunctional resin can promote coating shrinkage and the formation of nanoscale wrinkles, thus affecting the matte finish and surface abrasion resistance. Specifically, a higher proportion of polyfunctional resin results in a stronger matte finish and better abrasion resistance, but poorer adhesion. Therefore, to balance the gloss and adhesion of the final coating, the preferred mass ratio of the difunctional and polyfunctional waterborne polyurethane acrylate resins is (4-6):(5-7). Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] The first aspect of this invention provides an aqueous excimer UV coating comprising the following components in the following mass ratio:

[0018] 20%-30% of waterborne polyurethane acrylate resin

[0019] Multifunctional waterborne polyurethane acrylate resin 25%-35%,

[0020] UV monomers 35%-40%,

[0021] Photoinitiator 3%-6%,

[0022] Additives: 0.5%-1%.

[0023] In the above-mentioned waterborne excimer UV coating, the mass ratio of difunctional waterborne polyurethane acrylate resin to polyfunctional waterborne polyurethane acrylate resin is 20%-30%: 25%-35%. After the waterborne excimer UV coating is applied to the substrate, under the curing conditions of this application, the gloss and adhesion of the cured coating are well balanced.

[0024] In some examples, the synthesis steps of the 2-functional waterborne PUA resin are as follows: 50-60 parts of polyester diol / polyether diol (molecular weight 500-2000), 25-35 parts of isocyanate (IPDI, HDI, TDI), 5-10 parts of hydrophilic reactive monomer (dimethylolpropionic acid, dimethylolbutyric acid, polyethylene glycol), and 5-10 parts of catalyst (organotin, organobismuth catalyst) are mixed and reacted at 60-70℃ for 2-3 hours. Then, 15-20 parts of end-capped UV monomer (HEA / HEMA / HPA, etc.) and 0.1-0.5 parts of polymerization inhibitor are added, and the reaction continues at 65℃ for 2-3 hours. The temperature is then lowered to 45-50℃, and 5-8 parts of neutralizing agent (triethylamine, DMEA, etc.) are added and stirred for 0.5 hours to neutralize. Finally, 70-80 parts of water are added and dispersed by high-speed stirring. The synthesis steps of multifunctional waterborne PUA resin are as follows: 20-30 parts of polyester / polyether polyol (molecular weight 300-1000), 40-50 parts of isocyanate, 5-8 parts of hydrophilic reactive monomer, and catalyst are added together and reacted at 70℃ for 2-3 hours. Then, 15-20 parts of the first end-capping UV monomer (HEA, HEMA, HPA, etc.), 20-25 parts of the second end-capping monomer (PETA, TMPDE, etc.), and 0.1-0.5 parts of polymerization inhibitor are added. The reaction is continued at 65℃ for 2-3 hours. The temperature is then lowered to 45-50℃, and 5-8 parts of neutralizing agent are added and stirred for 0.5 hours to neutralize. Finally, 60-90 parts of water are added and dispersed by high-speed stirring.

[0025] In some examples, the functionality of the multifunctional waterborne polyurethane acrylate resin is ≥4, for example, it can be 4, 6, 10, 12, 16 or any value between them, to ensure that the coating produces severe and uniform surface shrinkage under 254nm excimer lamp irradiation, forming nanoscale wrinkles and achieving self-masking.

[0026] In some examples, the UV monomer includes trifunctional or difunctional monomers, or trifunctional and difunctional monomers in a mass ratio of 1-2:1. The UV monomer adjusts the viscosity of the coating and participates in the curing and crosslinking reaction.

[0027] Preferably, the photoinitiator is a free radical photoinitiator, which is selected from pyrolysis-type photoinitiators or hydrogen-abstraction-type photoinitiators. The photoinitiator absorbs ultraviolet light energy of specific wavelengths, such as 365nm, 395nm, 172nm, and 254nm, and undergoes photolysis or hydrogen ablation reaction to generate highly active free radicals. These free radicals attack the carbon-carbon double bonds (C=C) in the resin or monomer, initiating a chain polymerization reaction, causing the liquid oligomer to crosslink into a solid, dense coating within seconds.

[0028] In this application, the additives include leveling agents, which drive the coating to spontaneously flow and spread into a smooth, flat film before curing by reducing and homogenizing the surface tension of the coating.

[0029] The second aspect of this application provides a method for preparing the waterborne excimer UV coating, wherein the difunctional waterborne polyurethane acrylate resin, the polyfunctional waterborne polyurethane acrylate resin, the UV monomer, the photoinitiator, and the additives are weighed and mixed according to the mass ratio, and then stirred and dispersed at 35-45°C for 1-2 hours to obtain the waterborne excimer UV coating.

[0030] A third aspect of this application provides an article comprising a substrate and a coating applied to the substrate, wherein the coating is formed by applying and curing the water-based excimer UV coating. Preferably, the water-based excimer UV coating is sprayed onto the substrate to a thickness of 30-50 μm, dried and leveled at 50-70°C for 7-10 minutes, and then photocured to obtain a sample. The photocuring process involves first applying a 395nm LED light source at 600-800 mJ / cm². 2 Curing time is 3-5 seconds, followed by excimer lamp treatment at 800-1200 mJ / cm². 2 Curing for 5-10 seconds, followed by a mercury lamp light source of 300-800 mJ / cm². 2 Curing time is 5-10 seconds.

[0031] Preferably, the substrate is a wood substrate, a plastic substrate, such as PC, a glass substrate, a ceramic substrate, or a metal substrate.

[0032] To better understand the above technical solutions, the following will provide a detailed explanation of the specific implementation methods described in the specification.

[0033] I. Preparation Method

[0034] Example 1

[0035] This embodiment provides a method for preparing a water-based excimer UV coating, comprising the following steps:

[0036] Weigh each raw material according to the following mass percentages:

[0037] 20% waterborne polyurethane acrylate resin;

[0038] 4-functional waterborne polyurethane acrylate resin 35%;

[0039] The UV monomers comprise 40%, of which the UV monomers are trifunctional monomer ethoxylated (3)trimethylolpropane triacrylate (3EOTMPTA, CAS No. 28961-43-5) and difunctional monomer 1,6-hexanediol diacrylate (HDDA, CAS No. 13048-33-4), with a mass ratio of trifunctional monomers to difunctional monomers of 1:1.

[0040] Photoinitiator 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173, CAS No. 7473-98-5) 4.5%,

[0041] Dow Corning DC-57 leveling agent 0.5%;

[0042] Then, the raw materials are mixed and rapidly stirred and dispersed at 35°C for 2 hours to obtain a water-based excimer UV coating.

[0043] The synthesis steps of the 2-functional waterborne PUA resin are as follows:

[0044] Add 300g of polyester diol (Asahi Kasei Chemical XCP-2200NH) to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃, add 100g of Wanhua isophorone diisocyanate, 20g of hydrophilic reactive monomer dimethylolbutyric acid, and 0.1g of catalyst bismuth neodecanoate, react for 2 hours, and after the NCO content reaches the set value, add 40g of end-capping monomer hydroxyethyl acrylate and 0.15g of polymerization inhibitor p-hydroxyanisole, and continue to react at 70℃ for 2-3 hours. After the NCO% content is <0.1%, cool to 50℃, add 12g of neutralizing agent triethylamine, and stir to neutralize for 0.5 hours. Finally, add 450g of deionized water and stir at high speed to disperse.

[0045] The synthesis steps of 4-functional water-based PUA resin are as follows:

[0046] Add 200g of polyether polyol (Lanxing Dongda polyether 1000) to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃, add 135g of Wanhua IPDI, 15g of hydrophilic reactive monomer dimethylolbutyric acid, and 0.1g of catalyst dibutyltin laurate. React for 2 hours. After the NCO content reaches the set value, add 0.2g of polymerization inhibitor p-hydroxyanisole, then add 40g of the first end-capping monomer hydroxyethyl acrylate and 150g of the second end-capping monomer PETA. Continue the reaction at 70℃ for 3 hours. After the NCO% content is <0.1%, cool to 45℃, add 10g of neutralizing agent triethylamine, and stir to neutralize for 0.5 hours. Finally, add 550g of deionized water and stir at high speed to disperse.

[0047] Examples 2-4

[0048] The difference between this embodiment and Embodiment 1 is that the mass ratio of the 2-functional waterborne polyurethane acrylate resin and the 4-functional waterborne polyurethane acrylate resin is different, as detailed in Table 1. Otherwise, it is the same as Embodiment 1.

[0049] Example 5

[0050] The difference between this embodiment and Embodiment 1 is that the functionality of the multifunctional waterborne polyurethane acrylate resin is 6, while the rest is the same as in Embodiment 1.

[0051] The preparation method of the 6-functional waterborne polyurethane acrylate resin is as follows:

[0052] Add 100g of polyether polyol (Dexin Federal DL400) to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃, add 155g of Wanhua IPDI, 15g of hydrophilic reactive monomer dimethylolbutyric acid, and 0.1g of catalyst dibutyltin laurate, react for 2.5h, and after the NCO content reaches the set value, add 0.3g of polymerization inhibitor p-hydroxyanisole, then add 350g of end-capping monomer PETA, and continue reacting at 70℃ for 2h. After the NCO% content is <0.1%, cool to 50℃, add 10g of neutralizing agent triethylamine, and stir to neutralize for 0.5h, finally add 600g of deionized water and stir at high speed to disperse.

[0053] Example 6

[0054] The difference between this embodiment and Embodiment 1 is that the functionality of the multifunctional waterborne polyurethane acrylate resin is 10, while the rest is the same as in Embodiment 1.

[0055] The preparation method of 10-functional waterborne polyurethane acrylate resin is as follows:

[0056] Add 100g of polyester triol (PCL550) to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃, add 170g of Wanhua isocyanate IPDI, 16g of hydrophilic reactive monomer dimethylolpropionic acid, and 0.1g of catalyst dibutyltin laurate. React for 2.5h, and after the NCO content reaches the set value, add 0.4g of polymerization inhibitor p-hydroxyanisole, then add 23g of the first end-capping monomer hydroxyethyl methacrylate and 300g of the second end-capping monomer PETA. Continue the reaction at 70℃ for 3h, and after the NCO% content is <0.1%, cool to 50℃, add 12g of neutralizing agent DMEA, and stir to neutralize for 0.5h. Finally, add 600g of deionized water and stir at high speed to disperse.

[0057] Example 7

[0058] The difference between this embodiment and Embodiment 1 is that the functionality of the multifunctional waterborne polyurethane acrylate resin is 12, while the rest is the same as in Embodiment 1.

[0059] The preparation method of 12-functional waterborne polyurethane acrylate resin is as follows:

[0060] Add 100g of polyester triol (Juren Chemical PCL550) to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃. Add 100g of Wanhua IPDI, 50g of HDI, 15g of hydrophilic reactive monomer dimethylolpropionic acid, and 30g of PEG800. Add 25g of acetone to adjust the viscosity. Add 0.1g of dibutyltin laurate catalyst. React for 2.5h. After the NCO content reaches the set value, add 0.4g of polymerization inhibitor p-hydroxyanisole, then add 400g of end-capping monomer PETA. Continue the reaction at 70℃ for 3h. When the NCO% content is <0.1%, cool to 50℃, add 15g of neutralizing agent DMEA, and stir to neutralize for 0.5h. Finally, add 670g of deionized water and stir at high speed to disperse.

[0061] Example 8

[0062] The difference between this embodiment and Embodiment 1 is that the functionality of the multifunctional waterborne polyurethane acrylate resin is 16, while the rest is the same as in Embodiment 1.

[0063] The preparation method of 16-functional waterborne polyurethane acrylate resin is as follows:

[0064] Add 200g of Pastor polyether tetraol CAPA4101 to a flask, dehydrate under vacuum at 105℃ for 0.5h, then cool to 65℃, add 220g of Covestro IPDI, 20g of hydrophilic reactive monomer dimethylolpropionic acid, and 0.1g of catalyst dibutyltin laurate. React for 2.5h, and after the NCO content reaches the set value, add 0.4g of polymerization inhibitor p-hydroxyanisole, add 50g of acetone to adjust the viscosity, then add 375g of end-capping monomer PETA and 50g of second end-capping monomer TMPDE. Continue the reaction at 70℃ for 3h, and after the NCO% content is <0.1%, cool to 50℃, add 15g of neutralizing agent DMEA and stir to neutralize for 0.5h, and finally add 700g of deionized water and stir at high speed to disperse.

[0065] Comparative Examples 1-2

[0066] The difference between this comparative example and Example 1 is that the mass ratio of the difunctional waterborne polyurethane acrylate resin and the polyfunctional waterborne polyurethane acrylate resin is different, as detailed in Table 1. Otherwise, they are the same as in Example 1.

[0067] Table 1 Preparation processes of examples and comparative examples

[0068]

[0069] The performance of the waterborne excimer UV coatings prepared in the examples and comparative examples was tested using the following methods:

[0070] First, the water-based excimer UV coatings prepared in the examples and comparative examples were sprayed onto PC substrates with a coating thickness of 40 μm. After drying and leveling at 60°C for 8 min, the coatings were photocured to obtain sample pieces. The photocuring process was as follows: first, a 395nm LED light source with a 700mJ / cm² intensity was applied. 2 Curing for 4 seconds, followed by excimer lamp treatment at 800 mJ / cm². 2 Curing for 8 seconds, followed by a mercury lamp light source at 500 mJ / cm². 2 Curing time: 8 seconds.

[0071] The following tests were performed on the sample:

[0072] 1. Adhesion test: Cross-cut adhesion test;

[0073] 2. Gloss test: The surface gloss was determined under 60° conditions according to GB / T9754-2007;

[0074] 3. Abrasion resistance test: RCA paper tape abrasion resistance ASTM F2357-04 175g load;

[0075] 4. Weather resistance test: Place the sample at 90℃ and 95% humidity for 96 hours and observe whether the coating blister or peels off;

[0076] 5. Aging resistance test: The aging resistance test shall be conducted in accordance with GB / T14522-2008;

[0077] The test results are shown in Table 2.

[0078] Table 2 Performance test results of coatings in the examples and comparative examples

[0079]

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0082] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A water-based excimer UV coating, characterized in that, The components include the following components in the following mass ratios: 20%-30% of waterborne polyurethane acrylate resin Multifunctional waterborne polyurethane acrylate resin 25%-35%, UV monomers 35%-40%, Photoinitiator 3%-6%, Additives: 0.5%-1%.

2. The water-based excimer UV coating as described in claim 1, characterized in that, The functionality of the multifunctional waterborne polyurethane acrylate resin is ≥4.

3. The water-based excimer UV coating as described in claim 1, characterized in that, The functionality of the multifunctional waterborne polyurethane acrylate resin is 4-16.

4. The water-based excimer UV coating as described in claim 1, characterized in that, The functionality of the multifunctional waterborne polyurethane acrylate resin is 4, 6, 10, 12 or 16.

5. The waterborne excimer UV coating as described in claim 1, characterized in that, The UV monomer satisfies at least one of the following conditions: UV monomers include trifunctional or difunctional monomers; UV monomers include trifunctional and difunctional monomers with a mass ratio of 1-2:

1.

6. The waterborne excimer UV coating as described in claim 1, characterized in that, The photoinitiator is a free radical photoinitiator, which is selected from pyrolysis-type photoinitiators or hydrogen abstraction-type photoinitiators.

7. The water-based excimer UV coating as described in claim 1, characterized in that, The additives include leveling agents.

8. A method for preparing a waterborne excimer UV coating according to any one of claims 1-7, characterized in that, Weigh out the difunctional waterborne polyurethane acrylate resin, multifunctional waterborne polyurethane acrylate resin, UV monomer, photoinitiator, and additives according to the mass ratio, mix them, and then stir and disperse them at 35-45℃ for 1-2 hours to obtain a waterborne excimer UV coating.

9. An article, characterized in that, It includes a substrate and a coating applied to the substrate, wherein the coating is formed by applying and curing the water-based excimer UV coating as described in any one of claims 1-7.

10. The article of claim 9, characterized in that, The substrate can be any one of wood substrate, plastic substrate, glass substrate, ceramic substrate, or metal substrate.

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