A method for preparing a uv-cured touch coating

Abstract

This invention relates to a method for preparing a UV-curable tactile coating. The invention achieves a balance between film flexibility and scratch resistance through a microphase separation structure design. The physicochemical synergy of adding elastic polyurethane microspheres and crosslinkable organosilicon tactile agents constructs a long-lasting tactile system. Furthermore, the synergy between the film-forming resin and the silane coupling agent ensures high adhesion of the coating to various substrates. Ultimately, this invention achieves an environmentally friendly tactile paint and its preparation method that can be UV-cured rapidly within 30 seconds, possessing both extreme elasticity and high mechanical properties, thus meeting the multiple requirements of environmental protection, efficient production, and tactile quality in the automotive interior and consumer electronics industries.

Description

Technical Field

[0001] This invention relates to a method for preparing a UV-curable tactile paint with excellent elasticity, high abrasion resistance, and rapid curing, belonging to the field of polymer materials and coatings technology. Background Technology

[0002] Soft-touch paint, also known as elastic paint or rubber paint, is widely used in automotive interiors, consumer electronics, packaging, and daily necessities because its cured film has a soft, smooth feel, similar to human skin or rubber. It can significantly improve the comfort and high-end texture of products.

[0003] Currently, the mainstream soft-feel paints on the market are mainly two-component solvent-based polyurethane systems or baking-type systems. However, these traditional technologies have a series of prominent drawbacks: slow curing speed, high energy consumption, serious volatile organic compound (VOC) emissions, and poor overall coating performance (in pursuit of a soft feel, the wear resistance and scratch resistance of the paint film are often sacrificed, resulting in easy scratches and wear during product use; conversely, although increasing the crosslinking density can enhance wear resistance, the feel will become hard and brittle, losing the core advantage of "soft-feel paint").

[0004] With increasing environmental protection requirements, the development of a UV-curable, solvent-free or low-solvent paint that perfectly balances ultimate feel and high performance has become an urgent need in the industry. Although some UV-cured coatings have attempted to introduce a flexible feel, they generally suffer from problems such as the inability to balance feel and abrasion resistance, and poor adhesion. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for preparing a UV-curable tactile coating. By designing a microphase separation structure, a balance between film flexibility and scratch resistance is achieved. The physicochemical synergy of adding elastic polyurethane microspheres and crosslinkable organosilicon tactile agents constructs a long-lasting tactile system. Furthermore, the synergy between the film-forming resin and the silane coupling agent ensures high adhesion of the coating to various substrates. Ultimately, this invention achieves an environmentally friendly tactile coating and its preparation method that can be UV-cured rapidly within 30 seconds, possessing both extreme elasticity and high mechanical properties, thus meeting the multiple requirements of environmental protection, efficient production, and tactile quality in fields such as automotive interiors and consumer electronics.

[0006] The technical solution adopted in this invention is:

[0007] A method for preparing a UV-curable tactile coating includes the following steps:

[0008] (1) Synthesis of polyol (I): A certain amount of amine and catalyst were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction temperature was maintained at 20~40℃. A certain amount of ester compound was added. After heating to a certain temperature, the temperature was kept for a period of time. The amine compound content was measured to be less than 0.1%, and the reaction was stopped to obtain polyol (I).

[0009] (2) Synthesis of high-toughness aliphatic polyurethane acrylate oligomers: Add a certain amount of polyol, a certain amount of polyol (I) prepared in step (1), polymerization inhibitor and antioxidant to a three-necked flask. Add a mixture of diisocyanate and catalyst dropwise using a constant pressure funnel. Keep the reaction temperature at 40~55℃ and the dropwise addition time at 1~2 h. After all the dropwise addition is completed, raise the temperature to 80~100℃ and keep it at 1~4 h. Continue to add a certain amount of monomer containing -OH and -C=C groups dropwise using a constant pressure dropping funnel. Keep it at 1~8 h until the isocyanate absorption peak in the infrared absorption peak completely disappears. Stop the reaction and obtain high-toughness aliphatic polyurethane acrylate oligomers.

[0010] (3) Preparation of elastic polyurethane microsphere powder: Polyester diol (Mn=2000), isophorone diisocyanate, trimethylolpropane and catalyst are added to butanone and reacted at a certain temperature to obtain a polyurethane prepolymer solution containing hydroxyl groups. The solution is emulsified by high-speed shearing in an aqueous phase containing polyvinyl alcohol to form an O / W emulsion. The butanone is removed by heating and depressurization. Then a certain amount of amino silicone oil is added, stirred, filtered and dried to obtain the elastic polyurethane microsphere powder with organosilicon surface treatment.

[0011] (4) Preparation of UV-cured tactile coating:

[0012] Take the high-toughness aliphatic polyurethane acrylate oligomer obtained in step (2), special acrylate monomer, elastic polyurethane microsphere powder obtained in step (3), adhesion promoting resin, photoinitiator, and matting powder, grind them in a grinder to a fineness of ≤20 microns, add adhesion promoter, leveling agent, hand feel modifier, and defoamer under low-speed stirring, put them into a dispersion tank, disperse them at high speed until a uniform slurry is formed, filter them with a filter screen, and obtain the UV-cured hand feel coating.

[0013] As a preferred embodiment, in step (1), the amine is at least one or a mixture of diethanolamine and diethylamine; the catalyst is at least one or a mixture of diethylenetriamine and triethylenetetramine, and the amount added is 1000~3000 ppm of the total mass.

[0014] The ester compounds are at least one or a mixture of several of the following: ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, ethyleneene carbonate, and thioethylene carbonate.

[0015] The molar ratio of ester to amine is (1~1.08):1; the reaction temperature is 80~110℃; and the reaction time is 4~8 hours.

[0016] As a preferred embodiment, in step (2), the diisocyanate is at least one or a mixture of several of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), and the molar ratio of -NCO:OH is 2.1~2.5:1;

[0017] The antioxidant is at least one or a mixture of several of the following: di-dodecyl thiodipropionate (DLTDP), [2,4-di-tert-butylphenyl] phosphite, and di-octadecyl pentaerythritol diphosphite, with an addition amount of 0.1-0.5%.

[0018] The polyol is: at least one or a mixture of several polyester polyols and polyether polyols, Mn=2000, vacuum dehydrated to a water content ≤0.08% (determined by Karl Fischer method).

[0019] The polymerization inhibitor is one or a mixture of several of the following: hydroquinone, p-hydroxyanisole, phenothiazine, copper chloride, cuprous oxide, and copper sulfate;

[0020] The catalyst is: at least one or a mixture of several of the following: dibutyltin dilaurate, stannous octoate, or organotin compounds;

[0021] Monomers containing both -OH and -C=C groups include: hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), glyceryl diacrylate, trimethylolpropane diacrylate, polyethylene glycol (400) monoacrylate, pentaerythritol triacrylate (PETA), and dipentaerythritol pentaacrylate, or a mixture of at least one of these.

[0022] As a preferred embodiment, in the preparation method of the UV-curable tactile coating, in step (2), the amount of polyol (I) added accounts for 10-30% of the total polyol mass, the amount of polymerization inhibitor accounts for 1-3‰ of the total mass, the amount of antioxidant accounts for 1-3‰ of the total mass, the amount of diisocyanate added is such that the molar ratio of -NCO:OH is (2.1-2.5):1, the amount of monomers containing -OH and -C=C groups is controlled to have a molar equivalent ratio of hydroxyl to polyisocyanate of (1.2-2):1, and the amount of catalyst accounts for 3-5% of the total amount.

[0023] As a preferred embodiment, the preparation method of the UV-cured tactile coating includes step (3): taking 60-75 parts of polyester diol, 20-35 parts of isophorone diisocyanate, 3-10 parts of trimethylolpropane, and 1-2 parts of catalyst by weight, adding them to butanone, reacting at 70-90°C for 1-5 hours to obtain a hydroxyl-containing polyurethane prepolymer solution, emulsifying the solution at high speed in an aqueous phase containing 0.5-1% polyvinyl alcohol to form an O / W emulsion, heating to 70-90°C and removing butanone under reduced pressure, then adding 1-20% of total mass of amino silicone oil, stirring at 40-60°C for 1-4 hours, filtering, and drying to obtain silicone-surface-treated elastic polyurethane microsphere powder.

[0024] The catalyst is at least one or a mixture of several of dibutyltin dilaurate, stannous octoate, or organotin compounds.

[0025] As a preferred embodiment, in the preparation method of the UV-curable tactile coating, in step (4), 40-75 parts of the high-toughness aliphatic polyurethane acrylate oligomer obtained in step (2), 13-28 parts of the special acrylate monomer, 5-15 parts of the elastic polyurethane microsphere powder obtained in step (3), 2-5 parts of the adhesion promoting resin, 3-6 parts of the photoinitiator, and 3-8 parts of the matting agent are ground to a fineness ≤20 micrometers. Under low-speed stirring, 0.5-1.5 parts of the adhesion promoting agent, 0.3-1 parts of the leveling agent, 0.5-2 parts of the tactile modification agent, and 0.1-0.5 parts of the defoamer are added to the dispersion tank and dispersed at high speed at 800-1500 rpm for 20-40 minutes until a uniform slurry is formed. The slurry is then filtered using a 200-400 mesh filter to obtain the UV-curable tactile coating.

[0026] As a preferred embodiment, the high-toughness aliphatic polyurethane acrylate oligomers in step (3) have a number-average molecular weight between 3000 and 10000, and their elongation at break is ≥150% and their glass transition temperature Tg is ≤-20℃.

[0027] As a preferred embodiment, the special acrylate monomer is: benzyl alcohol acrylate, trihydroxyethyl isocyanurate triacrylate, PO3-TMPTA propoxylated trimethylolpropane triacrylate, 2-(2-biphenylethanol) acrylate, bis(trimethylolpropane)tetraacrylate (Di-TMPT4A), tetrahydrofurfuryl acrylate (THFA), triethylene glycol dimethacrylate (TEGDMA), 1,6-hexanediol dimethacrylate (HDDMA), 1,4-butanediol dimethacrylate (BDDMA), dipentaerythritol hexaacrylate (DPHA), triethoxylated trimethylolpropane triacrylate (EO3-TMPTA), isobornyl acrylate, isobornyl methacrylate, cyclotrimethylolpropane methyl acetal acrylate, and dipentaerythritol hexaacrylate, or a mixture of at least one or more of these.

[0028] In step (3) of the preferred embodiment, 60-75 parts of polyester diol, 20-35 parts of isophorone diisocyanate, 3-10 parts of trimethylolpropane, and 1-2 parts of catalyst are added to butanone and reacted at 70-90°C for 1-5 hours to obtain a hydroxyl-containing polyurethane prepolymer solution. The solution is then emulsified at high speed in an aqueous phase containing 0.5-1% polyvinyl alcohol to form an O / W emulsion. The temperature is raised to 70-90°C and the butanone is removed under reduced pressure. Then, 1-20% of the total mass of amino silicone oil is added, and the mixture is stirred at 40-60°C for 1-4 hours. After filtration and drying, the silicone-surface-treated elastic polyurethane microsphere powder is obtained.

[0029] The hand feel modifier is: a reactive silicone hand feel agent is at least one or a mixture of several of TEGO Rad 2500 or BYK-UV 3500; the polyethylene wax dispersion is at least one or a mixture of several of BYK-Ceraflour 996 and Ceridust 3620, and the mass ratio of the reactive silicone hand feel agent to the polyethylene wax dispersion is 1:(0.5~2).

[0030] The adhesion-promoting resin is: at least one or a mixture of several of chlorinated polypropylene or phosphate-modified acrylate;

[0031] The adhesion promoter is at least one or a mixture of several of the following: methacryloyloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, and vinyltriethoxysilane;

[0032] The photoinitiator is at least one or a mixture of several of the following: 1173, ITX, 2959, 369, 814, TPO, diphenyl ethyl ketone, and 2,4-dihydroxybenzophenone;

[0033] The matting agent is one or a mixture of at least one of ES400L, ES450L, and ES25L;

[0034] The defoamer is: at least one or a mixture of several types of silicone-modified acrylate and polyether types;

[0035] The leveling agent is at least one or a mixture of several of BYK-333, BYK-358N, and Anjikang 7358.

[0036] The beneficial effects of this invention are:

[0037] This invention creatively synthesizes aliphatic polyurethane acrylate with high toughness and low Tg as a continuous "soft segment" matrix, providing elasticity and flexibility. Self-made elastic polyurethane microsphere powder forms controllable physical micro-protrusions on the coating surface, producing an extremely smooth feel and avoiding the dryness caused by traditional inorganic fillers. At the same time, a crosslinkable organosilicon feel agent is used to form an extremely thin, low surface energy lubricating layer on the coating surface, giving it a delicate, dry and smooth feel similar to the skin surface and providing long-lasting stain resistance. In addition, the synergistic use of film-forming resin and reactive coupling agent ensures adhesion to a variety of substrates. Detailed Implementation

[0038] The present invention will be further described below with reference to embodiments, but the embodiments do not constitute a limitation on the scope of protection of the present invention:

[0039] Example 1

[0040] A method for preparing a UV-curable tactile coating includes the following steps:

[0041] (1) Synthesis of polyols: 107g of diethanolamine and 0.2g of triethylenediamine were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction temperature was kept at 20℃. 88g of ethylene carbonate was added. The temperature was raised to 80℃ and kept at that temperature for 5h. A sample was taken and measured by gas chromatography (GC). The reaction was stopped when the content of amine compounds was less than 0.1%, and the self-made triol was obtained.

[0042] (2) Synthesis of high-toughness aliphatic polyurethane acrylate oligomers: 400g polyester diol (Mn=2000), 38.6g of the self-made triol from step (1), 1.1g of p-hydroxyanisole, and 1.2g of di-dodecyl thiopropionate (DLTDP) were added to a three-necked flask. A mixture of 196g isophorone diisocyanate and 20g dibutyltin dilaurate was added dropwise using a constant pressure funnel. The reaction temperature was maintained at 40℃, and the addition time was 2 h. After all the addition was completed, the temperature was raised to 100℃ and kept at that temperature for 4 h. Then, 396g of pentaerythritol triacrylate was added dropwise using a constant pressure dropping funnel and kept at that temperature for 5 h until the infrared radiation reached 2270 cm⁻¹. -1 The characteristic absorption peaks disappeared, the reaction stopped, and a high-toughness aliphatic polyurethane acrylate oligomer was obtained.

[0043] (3) Preparation of elastic polyurethane microsphere powder: 75g of polyester diol (Mn=2000), 20g of isophorone diisocyanate, 4g of trimethylolpropane, and 1g of dibutyltin dilaurate were reacted in butanone at 75°C for 3 hours to obtain a polyurethane prepolymer solution containing hydroxyl groups. The solution was emulsified by high-speed shearing in an aqueous phase containing 0.5% polyvinyl alcohol to form an O / W emulsion. The temperature was raised to 80°C and the butanone was removed under reduced pressure. Then, 5g of amino silicone oil was added, and the mixture was stirred at 60°C for 1 hour. After filtration and drying, cross-linked polyurethane elastic microspheres with organosilicon surface treatment were obtained.

[0044] (4) Preparation of UV-cured hand-feel coating: The following components by weight are added to a dispersion tank and dispersed at a high speed of 800~1500 rpm for 20~40 minutes until a uniform slurry is formed: Take 57 parts of high-toughness aliphatic polyurethane acrylate oligomer, 20 parts of cyclotrimethylolpropane methyl acetal acrylate, 10 parts of elastic polyurethane microsphere powder, 2 parts of chlorinated polypropylene resin, 2 parts each of photoinitiator 1173 and 184, and 5 parts of ES400L matting powder. Grind them to a fineness of ≤20 microns. Add 0.5 parts of methacryloyloxypropyltrimethoxysilane, 0.5 parts of BYK-333 leveling agent, 0.5 parts of hand-feel modification agent (BYK-UV 3500 and Ceridust 3620 mass ratio 1:1), and 0.5 parts of defoamer under low-speed stirring. Filter with a 200~400 mesh filter to obtain UV-cured hand-feel coating.

[0045] Example 2

[0046] A method for preparing a UV-curable tactile coating includes the following steps:

[0047] (1) Synthesis of polyols: 107g of diethanolamine and 0.22g of triethylenediamine were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction temperature was kept at 40℃. 96g of fluoroethylene carbonate was added. The temperature was raised to 100℃ and kept at that temperature for 6 hours. A sample was taken and measured by gas chromatography (GC). The reaction was stopped when the content of amine compounds was less than 0.1%, and the self-made triol was obtained.

[0048] (2) Synthesis of high-toughness aliphatic polyurethane acrylate oligomers: Add 400g of polyether diol (Mn=2000), 40.6g of the triol prepared in step (1), 1.2g of p-hydroxyanisole, and 1.5g of di-dodecyl thiopropionate (DLTDP) to a three-necked flask. Add 205g of a mixture of isophorone diisocyanate and 25g of dibutyltin dilaurate dropwise using a constant pressure funnel. Maintain the reaction temperature at 50℃ and the dropwise addition time at 1 h. After all the dropwise addition is completed, raise the temperature to 90℃ and keep it at that temperature for 5 h. Continue to add 400g of pentaerythritol triacrylate dropwise using a constant pressure dropping funnel and keep it at that temperature for 5 h until the infrared light reaches 2270 cm⁻¹. -1The characteristic absorption peaks disappeared, the reaction stopped, and a high-toughness aliphatic polyurethane acrylate oligomer was obtained.

[0049] (3) Preparation of elastic polyurethane microsphere powder: 70g of polyester diol (Mn=2000), 25g of isophorone diisocyanate, 4g of trimethylolpropane, and 1g of dibutyltin dilaurate were reacted in butanone at 75°C for 3 hours to obtain a polyurethane prepolymer solution containing hydroxyl groups. The solution was emulsified by high-speed shearing in an aqueous phase containing 0.5% polyvinyl alcohol to form an O / W emulsion. The temperature was raised to 80°C and the butanone was removed under reduced pressure. Then, 5g of amino silicone oil was added, and the mixture was stirred at 60°C for 1 hour. After filtration and drying, cross-linked polyurethane elastic microspheres with organosilicon surface treatment were obtained.

[0050] (4) Preparation of UV-cured tactile coating: The following components by weight are added to a dispersion tank and dispersed at a high speed of 800-1500 rpm for 20-40 minutes until a uniform slurry is formed: Take 57 parts of high-toughness aliphatic polyurethane acrylate oligomer, 10 parts of isobornyl acrylate, 10 parts of isobornyl methacrylate, 10 parts of elastic polyurethane microsphere powder, 2 parts of chlorinated polypropylene resin, 2 parts each of photoinitiator 1173 and ITX, and 5 parts of ES400L matting agent. Grind them to a fineness of ≤20 microns. Under low-speed stirring, add 0.5 parts of methacryloyloxypropyltrimethoxysilane, 0.5 parts of BYK-333 leveling agent, and tactile modification additives (BYK-UV 3500 and BYK-Ceraflour). 0.5 parts of 996 (mass ratio 1:1) and 0.5 parts of defoamer, filtered through a 200-400 mesh filter, yields a UV-cured tactile coating.

[0051] Comparative Example 1 (lacking elastic microsphere powder)

[0052] Similar to Example 1, step (4) does not involve the addition of elastic polyurethane microsphere powder.

[0053] Comparative Example 2 (without tactile modifier)

[0054] Same as Example 2, but without the addition of feel-modifying additives.

[0055] Comparative Example 3 (without adhesion promoter)

[0056] Same as Example 2, but without adding adhesion promoter.

[0057] Comparative Example 4 (Two-component solvent-based tactile paint)

[0058] Use Musashi Coatings (NEORABASANSOFT NS781) commercially available two-component aliphatic polyurethane elastic feel paint (mixed according to the product TDS recommended ratio and process), mix evenly and spray onto ABS substrate, force dry at 60℃ for 40 minutes, dry film thickness 25~35 microns.

[0059] Performance testing

[0060] The paints obtained in Examples 1-2 and Comparative Examples 1-4 were sprayed onto pretreated ABS plastic sheets, with the paint film thickness controlled at 25 micrometers. The UV curing group used a high-pressure mercury lamp with an energy of 800 mJ / cm² and a curing time of 30 seconds. Comparative Example 4 was cured using a thermosetting process. After the paint film was left to stand for 24 hours, the following performance tests were conducted, and the results are shown in the table below:

[0061] Table 1. Coating performance testing and comparison

[0062] .

[0063] As can be seen from Table 1 above, through unique formulation design, Embodiments 1 and 2 of the present invention successfully integrate the high efficiency of UV curing with the ultimate feel and excellent wear resistance, achieving a performance balance that traditional thermosetting feel paints cannot achieve. Compared with the comparative example, it can solve the core pain points in this field.

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a UV-curable tactile coating, characterized in that, Includes the following steps: (1) Synthesis of polyol (I): A certain amount of amine and catalyst were added to a three-necked flask equipped with a stirrer and a thermometer. The reaction temperature was maintained at 20~40℃. A certain amount of ester compound was added. After heating to a certain temperature, the temperature was kept for a period of time. The amine compound content was measured to be less than 0.1%, and the reaction was stopped to obtain polyol (I). (2) Synthesis of high-toughness aliphatic polyurethane acrylate oligomers: Add a certain amount of polyol, a certain amount of polyol (I) prepared in step (1), polymerization inhibitor and antioxidant to a three-necked flask. Add a mixture of diisocyanate and catalyst dropwise using a constant pressure funnel. Keep the reaction temperature at 40~55℃ and the dropwise addition time at 1~2 h. After all the dropwise addition is completed, raise the temperature to 80~100℃ and keep it at 1~4 h. Continue to add a certain amount of monomer containing -OH and -C=C groups dropwise using a constant pressure dropping funnel. Keep it at 1~8 h until the isocyanate absorption peak in the infrared absorption peak completely disappears. Stop the reaction and obtain high-toughness aliphatic polyurethane acrylate oligomers. (3) Preparation of elastic polyurethane microsphere powder: Polyester diol (Mn=2000), isophorone diisocyanate, trimethylolpropane and catalyst are added to butanone and reacted at a certain temperature to obtain a polyurethane prepolymer solution containing hydroxyl groups. The solution is emulsified by high-speed shearing in an aqueous phase containing polyvinyl alcohol to form an O / W emulsion. The butanone is removed by heating and depressurization. Then a certain amount of amino silicone oil is added, stirred, filtered and dried to obtain the elastic polyurethane microsphere powder with organosilicon surface treatment. (4) Preparation of UV-cured tactile coating: Take the high-toughness aliphatic polyurethane acrylate oligomer obtained in step (2), special acrylate monomer, elastic polyurethane microsphere powder obtained in step (3), adhesion promoting resin, photoinitiator, and matting powder, grind them in a grinder to a fineness of ≤20 microns, add adhesion promoter, leveling agent, hand feel modifier, and defoamer under low-speed stirring, put them into a dispersion tank, disperse them at high speed until a uniform slurry is formed, filter them with a filter screen, and obtain the UV-cured hand feel coating.

2. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (1), the amine is at least one or a mixture of several of diethanolamine and diethylamine; The catalyst is at least one or a mixture of several of diethylenetriamine and triethylenetetramine, and the amount added is 1000~3000 ppm of the total mass. The ester compounds are at least one or a mixture of several of the following: ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, vinylene carbonate, and thioethylene carbonate; The molar ratio of ester to amine is (1~1.08):1; the reaction temperature is 80~110℃; and the reaction time is 4~8 hours.

3. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (2), the diisocyanate is at least one or a mixture of several of hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and diphenylmethane diisocyanate (MDI), and the molar ratio of -NCO:OH is 2.1~2.5:1; The antioxidant is at least one or a mixture of several of the following: di-dodecyl thiodipropionate (DLTDP), [2,4-di-tert-butylphenyl] phosphite, and di-octadecyl pentaerythritol diphosphite, with an addition amount of 0.1-0.5%. The polyol is: at least one or a mixture of several of polyester polyols and polyether polyols; The polymerization inhibitor is one or a mixture of several of the following: hydroquinone, p-hydroxyanisole, phenothiazine, copper chloride, cuprous oxide, and copper sulfate; The catalyst is: at least one or a mixture of several of the following: dibutyltin dilaurate, stannous octoate, or organotin compounds; Monomers containing both -OH and -C=C groups include: hydroxyethyl acrylate (HEA), hydroxyethyl methacrylate (HEMA), hydroxypropyl acrylate (HPA), glyceryl diacrylate, trimethylolpropane diacrylate, polyethylene glycol (400) monoacrylate, pentaerythritol triacrylate (PETA), and dipentaerythritol pentaacrylate, or a mixture of at least one of these.

4. The method for preparing the UV-curable tactile coating according to claim 3, characterized in that, In step (2), the amount of polyol (I) added accounts for 10-30% of the total polyol mass, the amount of polymerization inhibitor accounts for 1-3‰ of the total mass, the amount of antioxidant accounts for 1-3‰ of the total mass, the amount of diisocyanate added is the molar ratio of -NCO:OH is (2.1-2.5):1, the amount of monomers containing -OH and -C=C groups is controlled to have a molar equivalent ratio of hydroxyl to polyisocyanate of (1.2-2):1, and the amount of catalyst accounts for 3-5% of the total amount.

5. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, Step (3) is as follows: Take 60-75 parts by weight of polyester diol, 20-35 parts of isophorone diisocyanate, 3-10 parts of trimethylolpropane, and 1-2 parts of catalyst, and add them to butanone. React at 70-90℃ for 1-5 hours to obtain a hydroxyl-containing polyurethane prepolymer solution. Emulsify the solution at high speed in an aqueous phase containing 0.5-1% polyvinyl alcohol to form an O / W emulsion. Heat to 70-90℃ and remove butanone under reduced pressure. Then add 1-20% of total mass of amino silicone oil, stir at 40-60℃ for 1-4 hours, filter, and dry to obtain silicone-surface-treated elastic polyurethane microsphere powder.

6. The method for preparing the UV-curable tactile coating according to claim 5, characterized in that, The catalyst is at least one or a mixture of several of dibutyltin dilaurate, stannous octoate, or organotin compounds.

7. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (4), take 40-75 parts of the high-toughness aliphatic polyurethane acrylate oligomer obtained in step (2), 13-28 parts of the special acrylate monomer, 5-15 parts of the elastic polyurethane microsphere powder obtained in step (3), 2-5 parts of the adhesion promoting resin, 3-6 parts of the photoinitiator, and 3-8 parts of the matting agent. Grind them in a grinder until the fineness is ≤20 microns. Add 0.5-1.5 parts of the adhesion promoting agent, 0.3-1 parts of the leveling agent, 0.5-2 parts of the hand feel modifier, and 0.1-0.5 parts of the defoamer under low-speed stirring. Put them into a dispersion tank and disperse them at high speed at 800-1500 rpm for 20-40 minutes until a uniform slurry is formed. Filter it with a 200-400 mesh filter to obtain the UV-cured hand feel coating.

8. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (4), the high-toughness aliphatic polyurethane acrylate oligomers have a number-average molecular weight between 3000 and 10000, and their elongation at break is ≥150% and glass transition temperature Tg ≤-20℃. The special acrylate monomers are: benzyl alcohol acrylate, trihydroxyethyl isocyanurate triacrylate, PO3-TMPTA propoxylated trimethylolpropane triacrylate, 2-(2-biphenylethanol) acrylate, bis(trimethylolpropane)tetraacrylate (Di-TMPT4A), tetrahydrofurfuryl acrylate (THFA), triethylene glycol dimethacrylate (TEGDMA), 1,6-hexanediol dimethacrylate (HDDMA), 1,4-butanediol dimethacrylate (BDDMA), dipentaerythritol hexaacrylate (DPHA), triethoxylated trimethylolpropane triacrylate (EO3-TMPTA), isobornyl acrylate, isobornyl methacrylate, cyclotrimethylolpropane methyl acetal acrylate, and dipentaerythritol hexaacrylate, or a mixture of at least one of these.

9. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (4), the hand feel modifier is: the reactive silicone hand feel agent is at least one or a mixture of several of TEGO Rad 2500 or BYK-UV 3500; the polyethylene wax dispersion is at least one or a mixture of several of BYK-Ceraflour 996 and Ceridust 3620, and the mass ratio of the reactive silicone hand feel agent to the polyethylene wax dispersion is 1:(0.5~2). The adhesion promoting resin is: at least one or a mixture of several of chlorinated polypropylene or phosphate-modified acrylate; The adhesion promoter is at least one or a mixture of several of the following: methacryloyloxypropyltrimethoxysilane, vinyltrichlorosilane, vinyltris(β-methoxyethoxy)silane, and vinyltriethoxysilane.

10. The method for preparing the UV-curable tactile coating according to claim 1, characterized in that, In step (4), the photoinitiator is at least one or a mixture of several of the following: 1173, ITX, 2959, 369, 814, TPO, diphenyl ethyl ketone, and 2,4-dihydroxybenzophenone. The matting agent is one or a mixture of at least one of ES400L, ES450L, and ES25L; The defoamer is: at least one or a mixture of several types of silicone-modified acrylate and polyether types; The leveling agent is at least one or a mixture of several of BYK-333, BYK-358N, and Anjikang 7358.