A UV-resistant water-based coating, its preparation method and its application in air filters

Abstract

The invention relates to the technical field of air filter elements, and in particular to an anti-ultraviolet water-based coating, a preparation method thereof and an application thereof in an air filter element. The anti-ultraviolet water-based coating comprises raw materials: water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH regulator and water, and constructs a water-based photocuring system coating. After being coated on a polyester fiber support layer and cured, the coating has good adhesion to the polyester fiber support layer, and the anti-ultraviolet effect is improved by synergistic effect of aluminum silver paste, carbon nanotubes and photocatalyst, and effective ultraviolet blocking is formed on the polyester fiber support layer. At the same time, the anti-ultraviolet water-based coating avoids the addition of an existing oily anti-ultraviolet agent, which leads to a weakened electrostatic adsorption effect of a melt-blown PP layer after the coated polyester fiber support layer is combined with a melt-blown PP layer after being subjected to an electret treatment, and is conducive to maintaining the filtration efficiency of the air filter element.

Description

Technical Field

[0001] The invention relates to the technical field of air filter elements, and in particular to an anti-ultraviolet water-based coating, a preparation method thereof and application thereof in an air filter element. Background Art

[0002] The air filter element is a kind of filter, also called air filter cartridge, air filter, style, etc. It is mainly used for air filtration in engineering locomotives, automobiles, agricultural locomotives, laboratories, sterile operating rooms and various precision operating rooms.

[0003] Existing air filter elements mostly use a polyester fiber support layer bonded to a meltblown PP layer with the help of hot melt adhesive resin. However, the weather resistance of the meltblown PP layer is poor, and the light transmittance of the polyester fiber support layer is good, so the meltblown PP layer cannot be effectively protected from ultraviolet rays. In actual use, when light passes through the polyester fiber support layer under light, it is affected by ultraviolet rays, which easily causes the filaments of the meltblown PP layer to break, resulting in a decrease in the electrostatic adsorption effect of the meltblown PP layer, and the overall filtering effect is greatly weakened. If a coating containing an anti-ultraviolet agent is coated on the polyester fiber support layer, since the current anti-ultraviolet agents are mostly oily ultraviolet absorbers, the coated polyester fiber support layer is easily combined with the meltblown PP layer, which easily leads to a weakening of the electrostatic adsorption effect of the meltblown PP layer after the electret treatment. Summary of the invention

[0004] In order to overcome the shortcomings and deficiencies in the prior art, one of the purposes of the present invention is to provide an anti-ultraviolet water-based coating, which takes water-based polyurethane acrylate prepolymer as the main resin, and is added with aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH regulator and water to construct a water-based photocurable system coating. After being coated on a polyester fiber support layer and cured, the coating has good adhesion to the polyester fiber support layer, and the synergistic effect of aluminum silver paste, carbon nanotubes and photocatalyst is utilized to improve the anti-ultraviolet effect, and an effective ultraviolet barrier is formed on the polyester fiber support layer. At the same time, the addition of the existing oily ultraviolet protection agent causes the electrostatic adsorption effect of the melt-blown PP layer to be weakened after the coated polyester fiber support layer is combined with the melt-blown PP layer after the electret treatment.

[0005] The second object of the present invention is to provide a method for preparing an anti-ultraviolet water-based coating, which is simple to operate, convenient to control, high in production efficiency, and can be used for large-scale production.

[0006] The third purpose of the present invention is to provide an application of an anti-ultraviolet water-based coating in an air filter element. After the anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element and cured, an anti-ultraviolet water-based breathable membrane is formed, which effectively blocks ultraviolet rays.

[0007] One of the purposes of the present invention is achieved by the following technical solution: an anti-ultraviolet water-based coating, comprising the following raw materials in parts by weight:

[0008]

[0009] The anti-ultraviolet water-based coating of the invention uses water-based polyurethane acrylate prepolymer as a main resin, and is added with aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH regulator and water to construct a water-based photocuring system coating. After being coated on a polyester fiber support layer and cured, the coating has good adhesion to the polyester fiber support layer, and the anti-ultraviolet effect is improved by the synergistic effect of the aluminum silver paste, carbon nanotubes and photocatalyst, so that effective ultraviolet blocking is formed on the polyester fiber support layer, and at the same time, it is avoided that the electrostatic adsorption effect of the melt-blown PP layer after being subjected to electret treatment is weakened after the coated polyester fiber support layer is combined with the melt-blown PP layer due to the addition of an existing oily anti-ultraviolet agent.

[0010] Among them, the water-based polyurethane acrylate prepolymer used has good flexibility, bending resistance, chemical resistance, and strong adhesion. The added aluminum silver paste makes the surface of the membrane layer obtain a local reflection effect. Part of the light is reflected to the outside, and the remaining part enters the UV-resistant water-based coating. After photocuring, the UV-resistant water-permeable membrane absorbs ultraviolet light by the synergistic effect of carbon nanotubes and photocatalysts. The carbon nanotubes themselves are dark black and have better light absorption. In addition, the photocatalyst absorbs ultraviolet light and purifies the air, and can also play a bactericidal role to avoid bacterial growth and extend the service life. The carbon nanotubes and photocatalysts absorb light synergistically to prevent ultraviolet light from penetrating the polyester fiber support layer as much as possible to irradiate the meltblown PP layer of the air filter element, effectively avoiding the meltblown PP layer of the air filter element being irradiated by ultraviolet light, resulting in the breakage of the filaments of the meltblown PP layer, and causing the electrostatic adsorption effect of the meltblown PP layer to be reduced, thereby ensuring the continued high filtration effect of the air filter element. The added wetting agent is conducive to the uniform dispersion of aluminum paste, carbon nanotubes and photocatalyst in the system, and the synergistic effect with the coupling agent is conducive to promoting the binding of the anti-ultraviolet water-based coating after being dipped into the polyester fiber support layer, and promoting the adhesion of the anti-ultraviolet water-based coating to the polyester fiber support layer after curing. The added thixotropic agent is conducive to preventing the precipitation of aluminum paste, carbon nanotubes and photocatalysts and affecting the overall performance. The photoinitiator of the anti-ultraviolet water-based coating initiates polymerization under the action of ultraviolet light to cure the anti-ultraviolet water-based coating, thereby improving the stability of the anti-ultraviolet water-based coating. The added pH adjuster adjusts the pH value of the system to 7.5-8.5, so as to improve the light curing speed of the waterborne polyurethane acrylate prepolymer and the performance of the film layer after curing, which is more suitable for air filter elements.

[0011] In this embodiment, the aluminum-silver paste is selected from CW8103 or KC1801; and the particle size of the photocatalyst is 5-10 nm.

[0012] The above technical scheme is adopted, and the aluminum-silver paste selected is a water-based aluminum-silver paste whose surface has been treated with a hydrophilic surfactant and a low molecular weight corrosion inhibitor. It has good compatibility with the water-based polyurethane acrylate prepolymer system, good chemical stability and weather resistance, and good metallic effect, so that the surface of the film layer obtains a local reflection effect, so that part of the light is reflected to the outside world.

[0013] In this embodiment, the wetting agent is at least one of wet 270, CF-10 or Dynol 604, and the thixotropic agent is water-based thixotropic agent ECO-6520.

[0014] By adopting the above technical solution, the above water-based wetting agent is conducive to the uniform dispersion of aluminum paste, carbon nanotubes and photocatalyst in the system, and the synergistic effect with the coupling agent is conducive to promoting the binding of the anti-ultraviolet water-based coating after being dipped on the polyester fiber support layer, and promoting the adhesion of the anti-ultraviolet water-based coating on the polyester fiber support layer after curing; preferably, the wetting agent is a mixture of wet270, CF-10 and Dynol 604 in a weight ratio of 3:1:1-2. The above water-based thixotropic agent is conducive to preventing the precipitation of aluminum paste, carbon nanotubes and photocatalysts and affecting the overall performance.

[0015] In this embodiment, the photoinitiator is at least one of the aqueous photoinitiator 2959 , the aqueous photoinitiator 500 , or the aqueous photoinitiator 1173 .

[0016] By adopting the above technical solution, the above water-based photoinitiator is conducive to efficiently initiating the curing of the UV-resistant water-based coating under the action of ultraviolet light. More preferably, the photoinitiator is a mixture of water-based photoinitiator 2959 and water-based photoinitiator 500 in a weight ratio of 3:1-2.

[0017] In this embodiment, the coupling agent is selected from KH-460 or KH-450; the defoaming agent is at least one of aqueous defoaming agents BYK-019, BYK-065, BYK-037, BYK-028, BYK-024 or BYK-018.

[0018] By adopting the above technical solution, the synergistic effect of the above water-based coupling agent and the water-based wetting agent is conducive to promoting the binding of the anti-ultraviolet water-based coating after being dipped into the polyester fiber support layer, and promoting the adhesion of the anti-ultraviolet water-based coating to the polyester fiber support layer after curing. By adopting the above water-based defoaming agent, it is avoided that the coating foams and is affected by the foam after being applied to the polyester fiber support layer, thereby reducing its anti-ultraviolet performance after film formation.

[0019] In this embodiment, the co-solvent is at least one of propylene glycol methyl ether, propylene glycol butyl ether, diethylene glycol monobutyl ether or dipropylene glycol butyl ether; and the pH adjuster is a sodium hydroxide-water solution.

[0020] By adopting the above technical scheme, the added cosolvent promotes the dispersion of the coating; the sodium hydroxide-water solution is added to adjust the pH value of the system to 7.5-8.5, so as to improve the light curing speed of the waterborne polyurethane acrylate prepolymer and the performance of the film layer after curing, which is more suitable for air filter elements. Preferably, the concentration of the sodium hydroxide-water solution is 15-30wt%.

[0021] In this embodiment, the preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps:

[0022] Take 20-30 parts of diphenylmethane diisocyanate, 32-45 parts of polycaprolactone diol, 0.5-2 parts of catalyst, 1-3 parts of dimethylol propionic acid, 1-2 parts of acetone, 10-15 parts of reactive diluent, 0.01-0.03 parts of polymerization inhibitor and 30-50 parts of water by weight for later use;

[0023] After uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 38-45° C. to obtain a pre-reactant;

[0024] The pre-reactant is kept warm at 38-45°C and reacted until its isocyanate value is less than 8%, then dimethylol propionic acid and acetone are added and mixed, and the temperature is raised to 50-60°C and reacted until its isocyanate value is less than 2% to obtain a semi-finished product;

[0025] Add active diluent and polymerization inhibitor to the semi-finished product, mix, heat to 70-80°C, react until the isocyanate value is less than 0.01%, then remove acetone, cool, add water and stir evenly at high speed to obtain waterborne polyurethane acrylate prepolymer.

[0026] By adopting the above technical scheme, the obtained waterborne polyurethane acrylate prepolymer has good flexibility, bending resistance, chemical resistance and strong adhesion after curing, and is suitable for air filter elements.

[0027] Furthermore, the catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

[0028] The second object of the present invention is achieved by the following technical solution: The preparation method of the above-mentioned anti-ultraviolet water-based coating comprises the following steps:

[0029] Take waterborne polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts and set aside;

[0030] The aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water are stirred and dispersed uniformly to obtain a mixed dispersion;

[0031] Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 7.5-8.5, and then a mixed dispersion, a defoamer, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed for 1-3 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0032] Among them, preparing the mixed dispersion first is beneficial to the uniform dispersion of aluminum silver paste, carbon nanotubes and photocatalyst in the system, and the synergistic effect of the wetting agent and the coupling agent is beneficial to promoting the bonding of the anti-ultraviolet water-based coating after it is dipped into the polyester fiber support layer, and promoting the adhesion of the anti-ultraviolet water-based coating to the polyester fiber support layer after curing.

[0033] The third object of the present invention is achieved by the following technical solution: the application of the above-mentioned anti-ultraviolet water-based coating on the air filter element, the anti-ultraviolet water-based coating is dipped on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes, 800-1000mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

[0034] Furthermore, a polyester fiber support layer dipped and cured with an anti-ultraviolet water-based coating is combined with a melt-blown PP layer and then subjected to an electret process to form an air filter element.

[0035] The beneficial effects of the present invention are as follows: the anti-ultraviolet water-based coating of the present invention uses water-based polyurethane acrylate prepolymer as the main resin, and is added with aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH regulator and water to construct a water-based photocurable system coating. After being coated on a polyester fiber support layer and cured, the coating has good adhesion to the polyester fiber support layer, and the synergistic effect of aluminum silver paste, carbon nanotubes and photocatalyst is utilized to improve the anti-ultraviolet effect, and an effective ultraviolet barrier is formed on the polyester fiber support layer. At the same time, the addition of an existing oily anti-ultraviolet agent causes the electrostatic adsorption effect of the melt-blown PP layer to be weakened after the coated polyester fiber support layer is combined with the melt-blown PP layer after being subjected to an electret treatment.

[0036] The preparation method of the invention has the advantages of simple operation, convenient control and high production efficiency, and can be used for large-scale production.

[0037] The application of anti-ultraviolet water-based coating in air filter element is to dip the anti-ultraviolet water-based coating into the polyester fiber support layer of the air filter element and solidify it to form an anti-ultraviolet water-based breathable membrane, which can effectively block ultraviolet rays. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0039] Example 1

[0040] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0041]

[0042] The aluminum-silver paste is selected from CW8103; and the particle size of the photocatalyst is 7 nm.

[0043] The wetting agent is a mixture of wet 270, CF-10 and Dynol 604 in a weight ratio of 3:1:1.5, and the thixotropic agent is a water-based thixotropic agent ECO-6520.

[0044] The photoinitiator is a mixture of water-based photoinitiator 2959 and water-based photoinitiator 500 in a weight ratio of 3:1.5.

[0045] The coupling agent is selected from KH-460; the defoamer is aqueous defoamer BYK-019.

[0046] The auxiliary solvent is propylene glycol methyl ether; the pH regulator is a sodium hydroxide-water solution with a concentration of 23 wt%.

[0047] The preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps:

[0048] (R1), take 25 parts of diphenylmethane diisocyanate, 38 parts of polycaprolactone diol, 1.2 parts of catalyst, 2 parts of dimethylol propionic acid, 1.5 parts of acetone, 12 parts of reactive diluent, 0.02 parts of inhibitor and 40 parts of water by weight, and set aside;

[0049] (R2), after uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 42° C. to obtain a pre-reactant;

[0050] (R3), keeping the pre-reactant at 42° C., reacting until its isocyanate value is less than 8%, then adding dimethylolpropionic acid and acetone, mixing, raising the temperature to 55° C., reacting until its isocyanate value is less than 2%, to obtain a semi-finished product;

[0051] (R4), adding an active diluent and an inhibitor to the semi-finished product, heating to 75°C, reacting until the isocyanate value is less than 0.01%, then removing acetone, cooling, adding water, and stirring at a high speed of 1000 rpm to obtain a waterborne polyurethane acrylate prepolymer.

[0052] The catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

[0053] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0054] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0055] (S2), stirring and dispersing aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0056] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0057] The anti-ultraviolet water-based coating is applied to the air filter element. The anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes and 900mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

[0058] The polyester fiber support layer dipped and cured with the anti-ultraviolet water-based coating is combined with the melt-blown PP layer and then subjected to electret processing to form an air filter element.

[0059] Example 2

[0060] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0061]

[0062] The aluminum-silver paste is selected from CW8103; and the particle size of the photocatalyst is 5 nm.

[0063] The wetting agent is a mixture of wet 270, CF-10 and Dynol 604 in a weight ratio of 3:1:1, and the thixotropic agent is a water-based thixotropic agent ECO-6520.

[0064] The photoinitiator is a mixture of water-based photoinitiator 2959 and water-based photoinitiator 500 in a weight ratio of 3:1.

[0065] The coupling agent is selected from KH-450; the defoamer is aqueous defoamer BYK-065.

[0066] The auxiliary solvent is propylene glycol butyl ether; the pH regulator is a sodium hydroxide-water solution with a concentration of 15 wt%.

[0067] The preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps:

[0068] (R1), take 20 parts of diphenylmethane diisocyanate, 32 parts of polycaprolactone diol, 0.5 parts of catalyst, 1 part of dimethylol propionic acid, 1 part of acetone, 10 parts of reactive diluent, 0.01 parts of inhibitor and 30 parts of water by weight, and set aside;

[0069] (R2), after uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 38° C. to obtain a pre-reactant;

[0070] (R3), keeping the pre-reactant at 38° C., reacting until its isocyanate value is less than 8%, then adding dimethylolpropionic acid and acetone, mixing, raising the temperature to 50° C., reacting until its isocyanate value is less than 2%, to obtain a semi-finished product;

[0071] (R4), adding an active diluent and an inhibitor to the semi-finished product, heating to 70°C, reacting until the isocyanate value is less than 0.01%, then removing acetone, cooling, adding water, and stirring at a high speed of 1000 rpm to obtain a waterborne polyurethane acrylate prepolymer.

[0072] The catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

[0073] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0074] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0075] (S2), stirring and dispersing aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0076] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 7.5, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 1 min and then packaged to obtain an anti-ultraviolet waterborne coating.

[0077] The anti-ultraviolet water-based coating is applied to the air filter element. The anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes and 800mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

[0078] The polyester fiber support layer dipped and cured with the anti-ultraviolet water-based coating is combined with the melt-blown PP layer and then subjected to electret processing to form an air filter element.

[0079] Example 3

[0080] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0081]

[0082] The aluminum-silver paste is selected from CW8103; and the particle size of the photocatalyst is 10 nm.

[0083] The wetting agent is a mixture of wet 270, CF-10 and Dynol 604 in a weight ratio of 3:1:2, and the thixotropic agent is a water-based thixotropic agent ECO-6520.

[0084] The photoinitiator is a mixture of water-based photoinitiator 2959 and water-based photoinitiator 500 in a weight ratio of 3:2.

[0085] The coupling agent is selected from KH-450; the defoamer is aqueous defoamer BYK-018.

[0086] The auxiliary solvent is dipropylene glycol butyl ether; the pH regulator is a sodium hydroxide-water solution with a concentration of 30wt%.

[0087] The preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps:

[0088] (R1), take 30 parts of diphenylmethane diisocyanate, 45 parts of polycaprolactone diol, 2 parts of catalyst, 3 parts of dimethylol propionic acid, 2 parts of acetone, 15 parts of reactive diluent, 0.03 parts of inhibitor and 50 parts of water by weight, and set aside;

[0089] (R2), after uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 45° C. to obtain a pre-reactant;

[0090] (R3), keeping the pre-reactant at 45°C, reacting until its isocyanate value is less than 8%, then adding dimethylolpropionic acid and acetone, mixing, raising the temperature to 60°C, and reacting until its isocyanate value is less than 2%, to obtain a semi-finished product;

[0091] (R4), adding an active diluent and an inhibitor to the semi-finished product, heating to 80° C., reacting until the isocyanate value is less than 0.01%, then removing acetone, cooling, adding water, and stirring at a high speed of 1000 rpm to obtain a waterborne polyurethane acrylate prepolymer.

[0092] The catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

[0093] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0094] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0095] (S2), stirring and dispersing aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0096] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8.5, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 3 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0097] The anti-ultraviolet water-based coating is applied to the air filter element. The anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes and 1000mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

[0098] The polyester fiber support layer dipped and cured with the anti-ultraviolet water-based coating is combined with the melt-blown PP layer and then subjected to electret processing to form an air filter element.

[0099] Example 4

[0100] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0101]

[0102] The aluminum-silver paste is selected from KC1801; and the particle size of the photocatalyst is 8 nm.

[0103] The wetting agent is a mixture of wet 270, CF-10 and Dynol 604 in a weight ratio of 3:1:1.5, and the thixotropic agent is a water-based thixotropic agent ECO-6520.

[0104] The photoinitiator is a mixture of water-based photoinitiator 2959 and water-based photoinitiator 500 in a weight ratio of 3:1.2.

[0105] The coupling agent is selected from KH-450; the defoaming agent is a mixture of aqueous defoaming agents BYK-019 and BYK-018 in a weight ratio of 1:1.

[0106] The auxiliary solvent is a mixture of propylene glycol methyl ether and dipropylene glycol butyl ether in a weight ratio of 1:1; the pH regulator is a sodium hydroxide-water solution with a concentration of 25wt%.

[0107] The preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps:

[0108] (R1), take 28 parts of diphenylmethane diisocyanate, 38 parts of polycaprolactone diol, 0.8 parts of catalyst, 1.5 parts of dimethylol propionic acid, 1.2 parts of acetone, 13 parts of reactive diluent, 0.018 parts of inhibitor and 38 parts of water by weight, and set aside;

[0109] (R2), after uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 40° C. to obtain a pre-reactant;

[0110] (R3), keeping the pre-reactant at 40° C., reacting until its isocyanate value is less than 8%, then adding dimethylolpropionic acid and acetone, mixing, raising the temperature to 58° C., reacting until its isocyanate value is less than 2%, to obtain a semi-finished product;

[0111] (R4), adding an active diluent and an inhibitor to the semi-finished product, heating to 72° C., reacting until the isocyanate value is less than 0.01%, then removing acetone, cooling, adding water, and stirring at a high speed of 1000 rpm to obtain a waterborne polyurethane acrylate prepolymer.

[0112] The catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

[0113] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0114] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0115] (S2), stirring and dispersing aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0116] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0117] The anti-ultraviolet water-based coating is applied to the air filter element. The anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes and 1000mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

[0118] The polyester fiber support layer dipped and cured with the anti-ultraviolet water-based coating is combined with the melt-blown PP layer and then subjected to electret processing to form an air filter element.

[0119] Comparative Example 1

[0120] The difference between this comparative example and Example 1 is:

[0121] The anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0122]

[0123] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0124] (S1), taking water-based polyurethane acrylate prepolymer, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0125] (S2), stirring and dispersing the carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0126] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0127] Comparative Example 2

[0128] The difference between this comparative example and Example 1 is:

[0129] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0130]

[0131] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0132] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0133] (S2), stirring and dispersing aluminum silver paste, photocatalyst, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0134] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0135] Comparative Example 3

[0136] The difference between this comparative example and Example 1 is:

[0137] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0138]

[0139] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0140] (S1), taking water-based polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0141] (S2), stirring and dispersing the aluminum-silver paste, carbon nanotubes, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0142] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0143] Comparative Example 4

[0144] The difference between this comparative example and Example 1 is:

[0145] An anti-ultraviolet water-based coating comprises the following raw materials in parts by weight:

[0146]

[0147]

[0148] The anti-ultraviolet agent is a mixture of 2,4-dihydroxybenzophenone and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole in a weight ratio of 1:1.

[0149] The method for preparing the anti-ultraviolet water-based coating comprises the following steps:

[0150] (S1), taking water-based polyurethane acrylate prepolymer, UV protection agent, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts for later use;

[0151] (S2), stirring and dispersing the UV protection agent, coupling agent, wetting agent, cosolvent and water to obtain a mixed dispersion;

[0152] (S3) Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 8, and then a mixed dispersion, a defoaming agent, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed of 1000 rpm for 2 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

[0153] Comparative Example 5

[0154] The difference between this comparative example and Example 1 is:

[0155] The wetting agent is selected from the wetting agent with model HY-352.

[0156] Comparative Example 6

[0157] The difference between this comparative example and Example 1 is:

[0158] The waterborne polyurethane acrylate prepolymer is replaced by a waterborne UV resin (UV-77A).

[0159] Comparative Example 7

[0160] The difference between this comparative example and Example 1 is:

[0161] The carbon nanotubes are replaced by nanographene.

[0162] Comparative Example 8

[0163] The difference between this comparative example and Example 1 is:

[0164] This comparative example is a blank control example, that is, the polyester fiber support layer is not dipped in any coating, and is combined with the melt-blown PP layer and then subjected to electret processing to form an air filter element.

[0165] Performance Testing

[0166] Take the anti-ultraviolet water-based coatings of Examples 1-4 and Comparative Examples 1-7, and test their adhesion respectively;

[0167] The air filter elements of Examples 1-4 and Comparative Examples 1-8 were taken to test their filtration efficiency E1 and filtration efficiency E2 after UV aging treatment respectively;

[0168] The test method is as follows:

[0169] Adhesion: According to GB / T 1720-2020 paint film scratch test, test its adhesion level;

[0170] Filtration efficiency E1: According to GBT32085.1-2015 Automobile Air Conditioning Filter, the filtration efficiency is tested in a graded manner with a test area of ​​790cm 2 , Test dust standard: ISO12103-1, A2, for 0.3μm non-oily particles.

[0171] Filtration efficiency after UV aging treatment E2: The new air filter element was subjected to an accelerated aging test using UV lamp. The UV lamp model used in the test was UVB-313 and the test time was 168 hours. After the test, the graded filtration efficiency was tested according to GBT32085.1-2015 Automobile Air Conditioning Filter. The test area was 790 cm 2 , Test dust standard: ISO12103-1, A2, for 0.3μm non-oily particles.

[0172] The test results are shown in the following table:

[0173]

[0174]

[0175] As can be seen from the above table, the anti-ultraviolet water-based coating of the present invention uses water-based polyurethane acrylate prepolymer as the main resin, and adds aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoamer, cosolvent, pH regulator and water to construct a water-based photocurable system coating. After being coated on the polyester fiber support layer and cured, it has good adhesion to the polyester fiber support layer, and the anti-ultraviolet effect is improved by the synergistic effect of aluminum silver paste, carbon nanotubes and photocatalyst, and an effective ultraviolet barrier is formed on the polyester fiber support layer. At the same time, it is avoided that the electrostatic adsorption effect of the melt-blown PP layer after the electret treatment is weakened after the coated polyester fiber support layer is combined with the melt-blown PP layer by adding the existing oily anti-ultraviolet agent, which is beneficial to maintain the filtration efficiency of the air filter element. Among them, compared with comparative examples 1-3, the synergistic effect of aluminum silver paste, carbon nanotubes and photocatalyst used in Example 1 is significant for anti-ultraviolet light effect, which is beneficial to ensure that the air filter element still has a high filtration efficiency under light exposure and prolongs its service life. Compared with Comparative Example 4, the aluminum silver paste, carbon nanotubes and photocatalyst used in Example 1 can effectively avoid the adverse effects of the oily UV-blocking agent on the filtering effect of the air filter element. Compared with Comparative Examples 5-6, the special water-based polyurethane acrylate prepolymer and the specific proportion of wetting agent used in Example 1 have a significant promoting effect on the coating adhesion and filtering performance. Compared with Comparative Example 7, the carbon nanotubes used in Example 1 have a better overall anti-ultraviolet effect.

[0176] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. An anti-ultraviolet water-based coating, characterized in that: The invention comprises the following raw materials in parts by weight: The wetting agent is a mixture of wet 270, CF-10 and Dynol 604 in a weight ratio of 3:1:1-2; The cosolvent is at least one of propylene glycol methyl ether, propylene glycol butyl ether, diethylene glycol monobutyl ether or dipropylene glycol butyl ether; the pH regulator is sodium hydroxide-water solution; The preparation method of each portion of the waterborne polyurethane acrylate prepolymer comprises the following steps: Take 20-30 parts of diphenylmethane diisocyanate, 32-45 parts of polycaprolactone diol, 0.5-2 parts of catalyst, 1-3 parts of dimethylol propionic acid, 1-2 parts of acetone, 10-15 parts of reactive diluent, 0.01-0.03 parts of polymerization inhibitor and 30-50 parts of water by weight for later use; After uniformly mixing diphenylmethane diisocyanate, polycaprolactone diol and a catalyst, heating to 38-45° C. to obtain a pre-reactant; The pre-reactant is kept warm at 38-45°C and reacted until its isocyanate value is less than 8%, then dimethylol propionic acid and acetone are added and mixed, and the temperature is raised to 50-60°C and reacted until its isocyanate value is less than 2% to obtain a semi-finished product; Add active diluent and polymerization inhibitor to the semi-finished product, mix, heat to 70-80°C, react until the isocyanate value is less than 0.01%, then remove acetone, cool, add water and stir evenly at high speed to obtain waterborne polyurethane acrylate prepolymer.

2. The anti-ultraviolet water-based coating according to claim 1, characterized in that: The aluminum-silver paste is selected from CW8103 or KC1801; the particle size of the photocatalyst is 5-10 nm.

3. The anti-ultraviolet water-based coating according to claim 1, characterized in that: The thixotropic agent is water-based thixotropic agent ECO-6520.

4. The anti-ultraviolet water-based coating according to claim 1, characterized in that: The photoinitiator is at least one of aqueous photoinitiator 2959, aqueous photoinitiator 500 or aqueous photoinitiator 1173.

5. The anti-ultraviolet water-based coating according to claim 1, characterized in that: The coupling agent is selected from KH-460 or KH-450; the defoamer is at least one of aqueous defoamers BYK-019, BYK-065, BYK-037, BYK-028, BYK-024 or BYK-018.

6. The anti-ultraviolet water-based coating according to claim 1, characterized in that: The catalyst is dimethylcyclohexylamine, the active diluent is hydroxypropyl acrylate, and the inhibitor is phosphoric acid.

7. A method for preparing an anti-ultraviolet water-based coating as claimed in any one of claims 1 to 6, characterized in that: The steps include: Take waterborne polyurethane acrylate prepolymer, aluminum silver paste, carbon nanotubes, photocatalyst, wetting agent, thixotropic agent, photoinitiator, coupling agent, defoaming agent, cosolvent, pH adjuster and water according to weight parts and set aside; The aluminum-silver paste, carbon nanotubes, photocatalyst, coupling agent, wetting agent, cosolvent and water are stirred and dispersed uniformly to obtain a mixed dispersion; Under stirring conditions, a pH regulator is added to the waterborne polyurethane acrylate prepolymer to adjust the pH value of the system to 7.5-8.5, and then a mixed dispersion, a defoamer, a thixotropic agent and a photoinitiator are added, and the mixture is stirred at a high speed for 1-3 minutes and then packaged to obtain an anti-ultraviolet waterborne coating.

8. An application of the anti-ultraviolet water-based coating as claimed in any one of claims 1 to 6 in an air filter element, characterized in that: The anti-ultraviolet water-based coating is dip-coated on the polyester fiber support layer of the air filter element, and then baked at 60°C for 10 minutes, 800-1000mj / cm 2 The film is cured under ultraviolet light of radiation energy to form an ultraviolet resistant water-permeable breathable film attached to the polyester fiber support layer.

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