Ultraviolet-cured waterborne polyurethane acrylate resin, light-cured composition and wear-resistant ethanol-wiping-resistant coating

Abstract

The invention discloses ultraviolet curing waterborne polyurethane acrylate resin, a photocuring composition and a wear-resistant and ethanol-wiping-resistant coating. The preparation method comprises the following steps: mixing macromolecular dihydric alcohol and an organic silicon modifier, carrying out vacuum dehydration, respectively adding diisocyanate and a hydrophilic chain extender for reaction, then adding a hydroxyl-containing micromolecular chain extender for chain extension, then adding hydroxyl acrylate for end capping, adding triethylamine for neutralization to obtain a prepolymer, pouring the prepolymer into deionized water, and carrying out vacuum drying to obtain the waterborne polyurethane coating. The preparation method comprises the following steps: adding a water-based polyurethane acrylate resin into a solvent, dropwise adding a sulfydryl-containing micromolecule chain extender and an amino-containing micromolecule chain extender at the same time, stirring at a high speed to obtain ultraviolet-cured water-based polyurethane acrylate resin, preparing a light-cured composition from the ultraviolet-cured water-based polyurethane acrylate resin, coating a PET (Polyethylene Terephthalate) base material with the light-cured composition, and drying and photocuring to obtain the wear-resistant ethanol-wiping-resistant coating. The coating obtained by the invention has excellent ethanol wiping resistance and wear resistance.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to an ultraviolet light-cured waterborne polyurethane acrylate resin and a wear-resistant and ethanol-resistant wiping coating. Background Art

[0002] In recent years, with the continuous development of raw materials and processing technology, various optical parts based on polyester film (PET) have been widely used in many fields. PET material is favored for its excellent performance. It has excellent mechanical properties, heat resistance, high transmittance, low haze and high temperature resistance, making it superior to other materials in many aspects. Especially in the field of LCD production, such as liquid crystal display screens, a variety of PET optical films with different functions (light diffusion film, anti-glare film, brightening film, shielding conductive film) can be used. These functional PET optical films are made by coating various functional coatings on the surface of polyester film. Therefore, the preparation technology of various functional coatings is the key technology of optical films.

[0003] The most mature functional coating technology at present is solvent-based polyurethane coating, but its biggest disadvantage is that a large amount of organic solvents are used in the production process, resulting in large VOC (volatile organic compound) emissions and environmental pollution. Waterborne polyurethane uses water as a solvent, has low VOC emissions, and meets environmental protection requirements. However, in order to be better emulsified and dispersed in water, the molecular weight and cross-linking degree of waterborne polyurethane are relatively small, and most of them are mainly linear polymer materials, resulting in many defects in the use of waterborne polyurethane as a coating. Especially in the field of PET optical film, it is difficult to achieve the performance of solvent-based polyurethane in terms of wear resistance and ethanol wiping resistance, so it is necessary to improve the various properties of waterborne polyurethane materials through modification.

[0004] The organic combination of UV curing technology and waterborne polyurethane can not only solve the problem of adding a large amount of organic solvents in UV coatings to reduce viscosity, but also further improve the crosslinking degree and molecular weight of the coating on the basis of the original waterborne polyurethane. Yuan Nan et al. used IPDI and polypropylene glycol as raw materials, added DMPA, TMP and different proportions of hydroxyethyl acrylate and pentaerythritol triacrylate to prepare hyperbranched WPU emulsion. After photocuring, its water resistance and thermal stability were greatly improved; Zheng Chunsen et al. used self-made dihydroxy fluorinated polysiloxane and epoxy acrylate to modify waterborne polyurethane. Compared with the unmodified waterborne polyurethane coating, the coating had better thermal stability, higher mechanical strength and lower water absorption; Ou Wei et al. used KH-550, KH-560 and KH-792 to modify and prepare silicone-modified waterborne polyurethane emulsion. Comparing the performance of the coating before and after modification, the heat resistance of the modified coating was improved, the water absorption rate was reduced to varying degrees, and the water contact angle was increased.

[0005] However, the wear resistance and ethanol wiping resistance of the existing waterborne polyurethane coatings are still difficult to meet the application requirements. Therefore, how to design a waterborne polyurethane coating with both excellent wear resistance and excellent ethanol wiping resistance is an urgent problem to be solved. Summary of the invention

[0006] In view of the problems that the waterborne polyurethane coating in the prior art has poor wear resistance and ethanol wiping resistance, the object of the present invention is to provide a UV-curable waterborne polyurethane acrylate resin, a photocurable composition and a wear-resistant and ethanol-resistant wiping coating.

[0007] To achieve the above object, according to one aspect of the present invention, there is provided a method for preparing a UV-curable waterborne polyurethane acrylate resin, comprising the following steps: S1. Dehydrate the macromolecular diol and the organosilicon modifier under vacuum at 100-110°C; S2, after cooling to 68-72°C, add diisocyanate and hydrophilic chain extender to react until the isocyanate content reaches the theoretical value; S3, adding a hydroxyl-containing small molecule chain extender to react to a theoretical isocyanate value; S4, after cooling to 63-67°C, add hydroxy acrylate for end-capping and react to the theoretical isocyanate value; S5, after cooling to 55-60°C, triethylamine is added to neutralize the hydroxyl group to obtain a polyurethane prepolymer; S6, emulsifying and dispersing the prepolymer obtained in S5 in water, and simultaneously dropping a thiol-containing small molecule chain extender and an amino-containing small molecule chain extender, stirring and reacting to obtain the UV-curable waterborne polyurethane acrylate resin.

[0008] Furthermore, the macromolecular diol in S1 is a combination of one or more of polypropylene glycol, polyadipate-neopentyl glycol, polycaprolactone diol, and polycarbonate diol.

[0009] Furthermore, the organosilicon modifier in S1 is a polyether-modified polysiloxane compound.

[0010] Furthermore, the mass ratio of the macromolecular diol to the organosilicon modifier in S1 is (4-19):1.

[0011] Furthermore, the diisocyanate in S2 is a combination of one or more of diphenylmethane diisocyanate, isophorone diisocyanate, and toluene diisocyanate.

[0012] Furthermore, the hydrophilic chain extender in S2 is one of dimethylol propionic acid or dimethylol butyric acid.

[0013] Furthermore, the hydroxyl-containing small molecule chain extender in S3 is a combination of one or more of trimethylolpropane, trimethylolethane, hydroxyethylated bisphenol A, and bisphenol A diisopropyl alcohol ether.

[0014] Furthermore, the hydroxy acrylate in S4 is a combination of one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and pentaerythritol triacrylate.

[0015] Furthermore, the thiol-containing small molecule chain extender in S6 is pentaerythritol tetrakis(3-mercaptopropionic acid), pentaerythritol tetrakismercaptoacetic acid, trihydroxypropane tris(3-mercaptopropionic acid), and ethylene glycol dimercaptoacetate.

[0016] Furthermore, the amino-containing small molecule chain extender in S6 is a combination of one or more of ethylenediamine, diethylenetriamine, 3.3'-dimethyl-4.4'-diaminodicyclohexylmethane, and 4.4'-diaminodicyclohexylmethane.

[0017] According to another aspect of the present invention, provided is a UV-curable waterborne polyurethane acrylate resin obtained by the above method.

[0018] According to another aspect of the present invention, a photocurable composition is provided, comprising the above-mentioned UV-curable waterborne polyurethane acrylate resin, an active monomer containing hydroxyl acrylate, and a photoinitiator.

[0019] Furthermore, the active monomer containing hydroxyl acrylate is one or more mixtures of ethoxylated trimethylolpropane triacrylate, polyethylene glycol (600) diacrylate, ethoxylated trimethylolpropane trimethacrylate, and ethoxylated trimethylolpropane trimethacrylate.

[0020] Further, the photoinitiator is a combination of one or more of 2.4.6-trimethylbenzoyl-diphenylphosphine oxide, 2.4.6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, and bis(2.4.6-trimethylbenzoyl)phenylphosphine oxide.

[0021] Furthermore, by mass percentage, the ratio of the UV-curable waterborne polyurethane acrylate resin, the active monomer containing hydroxyl acrylate and the photoinitiator is (70%~94%): (5%~25%): (1%~5%).

[0022] According to another aspect of the present invention, provided is the use of the photocurable composition in preparing a wear-resistant and ethanol-resistant wipe coating.

[0023] According to another aspect of the present invention, a wear-resistant and ethanol-resistant wipe coating is provided. The photocurable composition described above is coated on a PET substrate using a wire rod, dried at 60-70°C, and then irradiated under a UV curing machine for 20-30s to obtain the wear-resistant and ethanol-resistant wipe coating.

[0024] Furthermore, the coating thickness is 4 μm.

[0025] Traditional waterborne polyurethane generally adopts small molecule polyol chain extension before emulsification and polyamine chain extension after emulsification. The balance between the two must have a relatively harsh relationship with the hydrophilic group and the salt ratio, but the yellowing and reaction of amine chain extenders are too fast, and the production conditions require to be completed at low temperature as much as possible. On the basis of the existing, the present invention improves the hardness of the film by introducing a variety of polycyclic chain extenders with strong rigidity, and at the same time introduces sulfhydryl groups during the post-chain extension, using CS bonds to balance hardness and toughness, and improves wear resistance; introduces chain extenders containing multiple functional groups to increase the branching degree of the waterborne polyurethane chain, improve the crosslinking degree of the coating, form a dense network structure, and the system reacts mildly, which solves this problem well. After that, it is further photocured to further improve the crosslinking degree and density of the coating, and prepare a UV-curable waterborne polyurethane acrylate coating with excellent wear resistance and outstanding ethanol wiping resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the preparation process of the UV-curable waterborne polyurethane acrylate resin wear-resistant and ethanol-resistant wipe coating in Example 1. DETAILED DESCRIPTION Example 1

[0027] 90.0g of polycaprolactone diol and 10.0g of polyether-modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum-dehydrated at 100°C and a vacuum condition of not less than 600 mmHg for 1 hour. The mixture was cooled to 70°C and 18.6g of dimethylolpropionic acid and 69.6g of toluene diisocyanate were added to react until the theoretical isocyanate value reached 7.3%. 3.4g of trimethylolpropane and 11.8g of hydroxyethylated bisphenol A were added to react until the theoretical isocyanate value reached 4.5%. When the mixture was cooled to 65°C, 7.5g of Pentaerythritol triacrylate and 3.3g of hydroxyethyl methacrylate were reacted to a theoretical isocyanate value of about 3.6%. When the temperature was lowered to 60°C, 11.9g of triethylamine was added to neutralize the carboxyl group in the reaction product. The reaction was carried out for 10min to obtain a polyurethane prepolymer. The prepolymer was poured into deionized water, and 3.7g of pentaerythritol tetrakis(3-mercaptopropionic acid) ester and 21.4g of 3.3-dimethyl-4.4-diaminodicyclohexylmethane were added dropwise. The mixture was stirred at high speed for 2h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0028] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific mass percentage ratio is 94% UV-curable waterborne polyurethane acrylate resin, 5% ethoxylated trimethylolpropane triacrylate, and 1% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain the photocurable composition.

[0029] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 60° C. for 0.5 h, and irradiated under a UV curing machine for 20 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm. Example 2

[0030] 80.0g of polypropylene glycol and 20.0g of polyether-modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum-dehydrated at 110°C and a vacuum condition of not less than 600mmHg for 2h. The mixture was cooled to 68°C and 20.3g of dimethylolbutyric acid and 88.8g of isophorone diisocyanate were added to react until the theoretical isocyanate value reached 7.1%. 3.4g of trimethylolpropane and 12.8g of bisphenol A diisopropyl ether were added to react until the theoretical isocyanate value reached 4.4%. When the temperature is lowered to 63°C, 7.5g of pentaerythritol triacrylate and 2.9g of hydroxyethyl acrylate are added to react until the theoretical isocyanate value is around 3.6%. When the temperature is lowered to 55°C, 11.9g of triethylamine is added to neutralize the carboxyl group in the reaction product. The reaction is carried out for 15min to obtain a polyurethane prepolymer. The prepolymer is poured into deionized water, and 3.3g of pentaerythritol tetrathioglycolate and 5.4g of ethylenediamine are added dropwise. The mixture is stirred at high speed for 3h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0031] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific weight percentage ratio is 88% of UV-curable waterborne polyurethane acrylate resin, 10% of polyethylene glycol (600) diacrylate, and 2% of 2,4.6-trimethylbenzoyl-ethoxy-phenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain a photocurable composition.

[0032] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 70° C. for 1 h, and irradiated under a UV curing machine for 25 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm. Example 3

[0033] 95.0 g of polyadipate-neopentyl glycol ester and 5.0 g of polyether-modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum-dehydrated at 105°C and a vacuum condition of not less than 600 mmHg for 1.5 h. The mixture was cooled to 72°C and 18.6 g of dimethylolpropionic acid and 48.8 g of diphenylmethane diisocyanate were added to react until the theoretical isocyanate value reached 5.9%. 11.8 g of hydroxyethylated bisphenol A and 3.1 g of trimethylolethane were added to react until the theoretical isocyanate value reached 3.7%. When the temperature drops to 67°C, 7.5g of pentaerythritol triacrylate and 3.3g of hydroxypropyl acrylate are added to react until the theoretical isocyanate value is around 2.9%. When the temperature drops to 58°C, 11.9g of triethylamine is added to neutralize the carboxyl group in the reaction product. The reaction takes 13min to obtain a polyurethane prepolymer. The prepolymer is poured into deionized water, and 3.9g of trihydroxypropane tris(3-mercaptopropionic acid) and 6.2g of diethylenetriamine are added dropwise. The mixture is stirred at high speed for 2.5h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0034] The UV-curable waterborne polyurethane acrylate resin obtained above is added with an active monomer and a photoinitiator to prepare a photocurable composition, wherein the specific weight percentage ratio is 82% of UV-curable waterborne polyurethane acrylate resin, 15% of ethoxylated trimethylolpropane trimethacrylate, and 3% of bis(2.4.6-trimethylbenzoyl)phenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain a photocurable composition.

[0035] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 65° C. for 0.8 h, and irradiated under a UV curing machine for 30 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm. Example 4

[0036] 85.0 g of polycarbonate diol and 15.0 g of polyether-modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum-dehydrated at 108 ° C and a vacuum condition of not less than 600 mmHg for 1.8 h. The mixture was cooled to 71 ° C and 18.6 g of dimethylol propionic acid and 69.6 g of toluene diisocyanate were added to react until the theoretical isocyanate value was about 7.8%. 3.1 g of trimethylolethane and 12.8 g of bisphenol A diisopropyl ether were added to react until the theoretical isocyanate value was about 4.8%. The mixture was cooled to 66 At ℃, 7.5g of pentaerythritol triacrylate and 3.6g of hydroxypropyl methacrylate were added to react until the theoretical isocyanate value reached about 3.9%. When the temperature was lowered to 58℃, 11.9g of triethylamine was added to neutralize the carboxyl group in the reaction product. The reaction lasted for 12min to obtain a polyurethane prepolymer. The prepolymer was poured into deionized water, and 3.2g of ethylene glycol dimercaptoacetate, 2.7g of ethylenediamine and 3.1g of diethylenetriamine were added dropwise. The mixture was stirred at high speed for 2.8h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0037] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific weight percentage ratio is 76% UV-curable waterborne polyurethane acrylate resin, 20% ethoxylated trihydroxypropane trimethacrylate, and 4% 2,4.6-trimethylbenzoyl-diphenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain a photocurable composition.

[0038] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 60° C. for 0.5 h, and irradiated under a UV curing machine for 20 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm. Example 5

[0039] 90.0 g of polycarbonate diol and 10.0 g of polyether modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum dehydrated at 103 ° C and a vacuum condition of not less than 600 mmHg for 1.3 h. The mixture was cooled to 69 ° C and 20.3 g of dimethylolbutyric acid and 88.8 g of isophorone diisocyanate were added to react until the theoretical isocyanate value was around 9.1%. 3.4 g of trimethylolpropane and 11.8 g of hydroxyethylated bisphenol A were added to react until the theoretical isocyanate value was around 5.6%. The mixture was cooled to 64 ° C and 10.0 g of polyether modified polysiloxane compound was added to react until the theoretical isocyanate value was around 5.6%. 7.5 g of pentaerythritol triacrylate and 3.3 g of hydroxyethyl methacrylate were added to react until the theoretical isocyanate value was about 4.6%. When the temperature was lowered to 56°C, 11.9 g of triethylamine was added to neutralize the carboxyl group in the reaction product. The reaction lasted for 14 min to obtain a polyurethane prepolymer. The prepolymer was poured into deionized water, and 3.7 g of pentaerythritol tetrakis(3-mercaptopropionic acid) and 6.2 g of 4.4'-diaminodicyclohexylmethane were added dropwise. The mixture was stirred at high speed for 2.3 h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0040] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific weight percentage ratio is 70% of UV-curable waterborne polyurethane acrylate resin, 25% of ethoxylated trimethylolpropane triacrylate, and 5% of bis(2.4.6-trimethylbenzoyl)phenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain a photocurable composition.

[0041] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 70° C. for 1 h, and irradiated under a UV curing machine for 25 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm.

[0042] Comparative Example 1 100.0 g of polybutylene adipate with a molecular weight of 2000 was vacuum dehydrated at 100° C. and a vacuum condition of not less than 600 mmHg for 2 h, cooled to 70° C., 20.3 g of dimethylolbutyric acid and 88.8 g of isophorone diisocyanate were added to react until the theoretical isocyanate value reached 9.2%, 3.4 g of trimethylolpropane and 11.8 g of hydroxyethylated bisphenol A were added to react until the theoretical isocyanate value reached 5.7%, 7.5 g of pentaerythritol triacrylate and 3.3 g of hydroxyethyl methacrylate were added when the temperature was cooled to 65° C., the theoretical isocyanate value reached 4.6%, 11.9 g of triethylamine was added to neutralize the carboxyl group in the reaction product when the temperature was cooled to 60° C., the polyurethane prepolymer was reacted for 10 min, the prepolymer was poured into deionized water, 3.2 g of ethylenediamine and 3.6 g of diethylenetriamine were added dropwise, and the mixture was stirred at high speed for 2 h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0043] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific weight percentage ratio is 85% of UV-curable waterborne polyurethane acrylate resin, 14% of ethoxylated trimethylolpropane triacrylate, and 1% of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain a photocurable composition.

[0044] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 60° C. for 0.5 h, and irradiated under a UV curing machine for 25 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm.

[0045] Comparative Example 2 90.0 g of polycaprolactone diol and 10.0 g of polyether-modified polysiloxane compound, both with a molecular weight of 2000, were mixed and vacuum-dehydrated at 100 ° C and a vacuum condition of not less than 600 mmHg for 1 h, cooled to 70 ° C, 18.6 g of dimethylol propionic acid and 69.6 g of toluene diisocyanate were added to react until the theoretical isocyanate value was about 7.3%, 3.4 g of trimethylolpropane and 11.8 g of hydroxyethylated bisphenol A were added to react until the theoretical isocyanate value was about 4.5%, and cooled to 50 ° C. At 65°C, 7.5 g of pentaerythritol triacrylate and 3.3 g of hydroxyethyl methacrylate were added to react until the theoretical isocyanate value was around 3.6%. When the temperature was lowered to 60°C, 11.9 g of triethylamine was added to neutralize the carboxyl group in the reaction product. The reaction was carried out for 10 min to obtain a polyurethane prepolymer. The prepolymer was poured into deionized water, and 25.0 g of 3.3-dimethyl-4.4-diaminodicyclohexylmethane was added dropwise. The mixture was stirred at high speed for 2 h to obtain a UV-curable waterborne polyurethane acrylate resin.

[0046] The UV-curable waterborne polyurethane acrylate resin obtained above is added with active monomers and photoinitiators to prepare a photocurable composition, wherein the specific mass percentage ratio is 94% UV-curable waterborne polyurethane acrylate resin, 5% ethoxylated trimethylolpropane triacrylate, and 1% 2,4,6-trimethylbenzoyl-diphenylphosphine oxide; the above raw materials are stirred and mixed evenly to obtain the photocurable composition.

[0047] The photocurable composition obtained above was coated on a PET substrate using a wire rod, dried in an oven at 60° C. for 0.5 h, and irradiated under a UV curing machine for 20 s to obtain a UV-curable waterborne polyurethane acrylate coating with a thickness of 4 μm.

[0048] The performance of the UV-curable waterborne polyurethane acrylate wear-resistant and ethanol-resistant wiping coatings described in Examples 1 to 5 and the comparative example was tested, and the test results are shown in Table 1.

[0049] Table 1 Test items Test Method Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Ethanol wiping resistance GB / T23989-2009 50 times 70 times 350 times 340 times 344 times 349 times 352 times hardness GB / T2411-2008 50.0HD 53.0HD 80.5HD 80.4HD 80.0HD 79.9HD 80.0HD Wear weight loss rate Use steel wool to rub the coating surface. The steel wool model is GRADE#0000, with a load of 500g. Test 500 times to see the weight loss rate after wear. 0.100% 0.110% 0.005% 0.005% 0.005% 0.005% 0.005% The scope of protection claimed by the present invention is not limited to the above specific embodiments. For those skilled in the art, the present invention may have various deformations and changes. Any modifications, improvements and equivalent substitutions made within the concept and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a UV-curable waterborne polyurethane acrylate resin, characterized in that: The following steps are involved: S1. Dehydrate the macromolecular diol and the organosilicon modifier under vacuum at 100-110°C; S2, after cooling to 68-72°C, add diisocyanate and hydrophilic chain extender to react until the isocyanate content reaches the theoretical value; S3, adding a hydroxyl-containing small molecule chain extender to react to a theoretical isocyanate value; S4, after cooling to 63-67°C, add hydroxy acrylate for end-capping and react to the theoretical isocyanate value; S5, after cooling to 55-60°C, triethylamine is added to neutralize the hydroxyl group to obtain a polyurethane prepolymer; S6, emulsifying and dispersing the prepolymer obtained in S5 in water, and simultaneously dropping a thiol-containing small molecule chain extender and an amino-containing small molecule chain extender, stirring and reacting to obtain the UV-curable waterborne polyurethane acrylate resin.

2. The method according to claim 1, characterized in that The macromolecular diol in S1 is a combination of one or more of polypropylene glycol, polyadipate-neopentyl glycol, polycaprolactone diol, and polycarbonate diol.

3. The method according to claim 1 or 2, characterized in that: The organosilicon modifier described in S1 is a polyether-modified polysiloxane compound.

4. The method according to claim 3, characterized in that: The mass ratio of the macromolecular diol to the organosilicon modifier described in S1 is (4~19):

1.

5. The method according to claim 1 or 4, characterized in that: The diisocyanate in S2 is a combination of one or more of diphenylmethane diisocyanate, isophorone diisocyanate and toluene diisocyanate.

6. The method according to claim 5, characterized in that: The hydrophilic chain extender in S2 is one of dimethylol propionic acid or dimethylol butyric acid.

7. The method according to claim 1 or 6, characterized in that: The hydroxyl-containing small molecule chain extender in S3 is a combination of one or more of trimethylolpropane, trimethylolethane, hydroxyethylated bisphenol A, and bisphenol A diisopropyl alcohol ether.

8. The method according to claim 7, characterized in that: The hydroxy acrylate in S4 is a combination of one or more of hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and pentaerythritol triacrylate.

9. The method according to claim 1 or 8, characterized in that: The thiol-containing small molecule chain extender in S6 is pentaerythritol tetrakis(3-mercaptopropionic acid), pentaerythritol tetrakismercaptoacetic acid, trihydroxypropane tris(3-mercaptopropionic acid), and ethylene glycol dimercaptoacetate.

10. The method according to claim 9, characterized in that: The amino-containing small molecule chain extender in S6 is a combination of one or more of ethylenediamine, diethylenetriamine, 3.3'-dimethyl-4.4'-diaminodicyclohexylmethane, and 4.4'-diaminodicyclohexylmethane.

11. The UV-curable waterborne polyurethane acrylate resin obtained by the method of any one of claims 1 to 10.

12. A photocurable composition, characterized in that: It comprises the UV-curable waterborne polyurethane acrylate resin as claimed in claim 11, and an active monomer containing hydroxyl acrylate and a photoinitiator.

13. The photocurable composition according to claim 12, characterized in that: The active monomer containing hydroxyl acrylate is one or more mixtures of ethoxylated trimethylolpropane triacrylate, polyethylene glycol (600) diacrylate, ethoxylated trimethylolpropane trimethacrylate, and ethoxylated trimethylolpropane trimethacrylate.

14. The photocurable composition according to claim 12 or 13, characterized in that: The photoinitiator is a combination of one or more of 2.4.6-trimethylbenzoyl-diphenylphosphine oxide, 2.4.6-trimethylbenzoyl-ethoxy-phenylphosphine oxide, and bis(2.4.6-trimethylbenzoyl)phenylphosphine oxide.

15. The photocurable composition according to claim 12, characterized in that: Calculated by mass percentage, the ratio of the UV-curable waterborne polyurethane acrylate resin, the active monomer containing hydroxyl acrylate and the photoinitiator is (70%~94%): (5%~25%): (1%~5%).

16. Use of the photocurable composition according to claims 12 to 15 in preparing a wear-resistant and ethanol-resistant wiping coating.

17. A wear-resistant and ethanol-resistant wiping coating, characterized in that: The photocurable composition according to claims 12 to 15 is coated on a PET substrate using a wire rod, dried at 60 to 70° C., and then irradiated under a UV curing machine for 20 to 30 seconds to obtain the wear-resistant and ethanol-resistant wiping coating.

18. The wear-resistant and ethanol-resistant wiping coating according to claim 17, characterized in that: The coating thickness is 4 μm.

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