Coating, preparation method and application

Abstract

The invention discloses a coating as well as a preparation method and application thereof, and relates to the technical field of coating preparation. The coating is prepared from nano particle sol and a waterborne polyurethane resin prepolymer, the nano-particle sol is prepared from the following raw materials: nano-silica particles, a silane coupling agent composition and a solvent; wherein the silane coupling agent composition is prepared from fluorosilane and long-chain alkyl silane. The prepared coating is environmentally friendly and harmless to human bodies, a coating formed by the coating has high hydrophobic and oleophobic performance and an easy-to-clean effect, meanwhile, the coating is simple in preparation method and good in constructability and has good binding force with the surface of a panel of a household appliance, and both the mechanical performance and weather resistance of the coating can meet daily use requirements.

Description

Technical Field

[0001] The present invention relates to the technical field of coating preparation, and in particular to a coating, a preparation method and application thereof. Background Art

[0002] With the development of the economy and society and the improvement of people's living standards, consumers have increasingly higher requirements for the cleaning resistance of electrical appliances for daily use. For example, when consumers use air conditioners, the panels of the air conditioners and the inner surfaces of the air conditioners that can be opened and touched by consumers are easily stained with oil and other stains. The oleophobicity of traditional air conditioner panels and inner surface coatings of air conditioners is poor, resulting in conventional cleaning methods that cannot easily remove oil and other stains on the air conditioner panels or inner surfaces. Cleaning with strong alkaline detergents or high-hardness cleaning products such as steel wool can easily cause scratches, corrosion and other phenomena, which affects the appearance of the air conditioner and causes great trouble to consumers. Summary of the invention

[0003] The main purpose of the present invention is to develop an environmentally friendly and harmless coating. The coating formed by the coating has strong hydrophobic and oleophobic properties and is easy to clean. At the same time, the coating has a simple preparation method, good construction performance, and good bonding strength with the panel surface of household appliances. The mechanical properties and weather resistance of the coating can meet daily use requirements.

[0004] To achieve the above-mentioned purpose, the present invention provides a coating, which includes a nanoparticle sol and an aqueous polyurethane resin prepolymer; the nanoparticle sol includes the following raw materials in parts by weight: nano silicon dioxide particles: 1 to 3.5 parts; a silane coupling agent composition: 5 to 10 parts; a solvent: 70 to 240 parts; wherein the silane coupling agent composition includes fluorosilane and long-chain alkyl silane.

[0005] In one embodiment, the fluorosilane includes at least one of perfluoroalkyltrimethoxysilane and perfluoroalkyltriethoxysilane.

[0006] In one embodiment, the perfluoroalkyltrimethoxysilane includes at least one of perfluorooctyltrimethoxysilane, perfluorodecyltrimethoxysilane, perfluorotetradecyltrimethoxysilane, and perfluoroheptadecantrimethoxysilane.

[0007] In one embodiment, the perfluoroalkyltriethoxysilane includes at least one of perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, perfluorotetradecyltriethoxysilane, and perfluoroheptadecantriethoxysilane.

[0008] In one embodiment, the long-chain alkyl silane includes at least one of long-chain alkyl trimethoxy silane and long-chain alkyl triethoxy silane.

[0009] In one embodiment, the long-chain alkyltrimethoxysilane includes at least one of n-octyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, and docosyltrimethoxysilane.

[0010] In one embodiment, the long-chain alkyltriethoxysilane includes at least one of n-octyltriethoxysilane, dodecyltriethoxysilane, hexadecyltriethoxysilane, octadecyltriethoxysilane, and docosyltriethoxysilane.

[0011] In one embodiment, the silane coupling agent composition further includes alkenyl silane.

[0012] In one embodiment, the alkenyl silane includes at least one of vinyltrimethoxysilane, vinyltriethoxysilane, acryltrimethoxysilane, acryltriethoxysilane, 5-hexenyltrimethoxysilane, 5-hexenyltriethoxysilane, 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, 10-dodecenyltrimethoxysilane, 10-dodecenyltriethoxysilane, 18-octadecenyltrimethoxysilane, 18-octadecenyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane.

[0013] In one embodiment, in the silane coupling agent composition, the weight ratio of the fluorosilane, the long-chain alkylsilane and the alkenylsilane is (3-5): (1-3): (1-2).

[0014] In one embodiment, the nano-silicon dioxide particles include at least one of nano-aluminum oxide, nano-zinc oxide, nano-titanium dioxide, nano-calcium carbonate, nano-silicon dioxide, nano-graphene, carbon nanotubes, nano-boron nitride, nano-titanium nitride, and nano-silicon nitride.

[0015] In one embodiment, in the nanoparticle sol, the weight ratio of the fluorosilane to the nano-silica particles is (3-5):1.

[0016] In one embodiment, the waterborne polyurethane resin prepolymer includes the following raw materials in parts by weight: bio-based polyether diol: 20 to 40 parts; isocyanate: 20 to 40 parts; catalyst: 0.6 to 0.9 parts; end-capping agent: 2 to 5 parts; functional additive 2 to 5 parts; organic acid: 0.02 to 0.04 parts; inorganic acid: 0.01 to 0.03 parts; antioxidant: 0.01 to 0.04 parts; deionized water: 10 to 20 parts.

[0017] In one embodiment, in the waterborne polyurethane resin prepolymer, the functional additive includes at least one of 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, and dihydroxybenzoic acid.

[0018] In one embodiment, the coating further includes an auxiliary component; the auxiliary component includes the following raw materials in parts by weight: defoamer: 0.5 to 10 parts; light stabilizer: 1 to 10 parts; leveling agent: 0.5 to 5 parts; matting agent: 10 to 50 parts; acrylate compound: 3 to 5 parts; organic solvent: 30 to 60 parts; deionized water: 20 to 50 parts.

[0019] In one embodiment, in the coating, the weight ratio of the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary component is (50-70): (20-30): (10-20).

[0020] The present invention also provides a method for preparing a coating, which comprises the following steps:

[0021] S10, dispersing nano-silica particles in a solvent, adjusting the pH to alkaline, adding a silane coupling agent composition to react, adjusting the pH to neutral or weakly acidic, allowing the solvent to stand, filtering and collecting the filtrate to obtain a nano-particle sol;

[0022] S20, mixing the waterborne polyurethane resin prepolymer and the nanoparticle sol prepared in step S10 according to a proportion to prepare the coating.

[0023] In one embodiment, between step S10 and step S20, the following steps are further included:

[0024] S11: vacuum dehydrating the bio-based polyether diol at 35-65° C., then adding deionized water, isocyanate, functional additives, catalysts, organic acids and inorganic acids, stirring and reacting at 65-75° C. to obtain a polyurethane prepolymer, then adding a capping agent and stirring and reacting, adjusting the pH to neutral, and obtaining a waterborne polyurethane resin prepolymer;

[0025] S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, an acrylate compound, an organic solvent and deionized water, and filtering the filtrate to obtain an auxiliary agent component.

[0026] In one embodiment, in the step S20, the nanoparticle sol prepared in the step S10, the waterborne polyurethane resin prepolymer prepared in the step S11, and the auxiliary component prepared in the step S12 are mixed according to a proportion to prepare the coating.

[0027] The present invention also provides a household appliance, wherein the coating is applied to the household appliance.

[0028] In one embodiment, the household appliance includes an air conditioner, and the coating forms a hydrophobic and oleophobic coating on a panel surface of the air conditioner through a thermal cross-linking and curing process.

[0029] The technical scheme of the present invention designs a coating, which uses a water-based polyurethane resin prepolymer as a base material, reduces the environmental pollution and construction toxicity caused by organic coatings, and uses nano-silica particles modified by long-chain alkyl silane coupling agents, fluorosilane coupling agents and silane coupling agents containing carbon-carbon double bonds to form a stable silica sol. The sol-gel method is used, and the production cost is lower, the preparation process is simple, and it is easy to operate; the silica sol is used as the main filler of the coating, so that the prepared coating has good hydrophobicity and oleophobicity, and is more convenient to clean. At the same time, the coating also has good wear resistance and weather resistance and high hardness; and the water contact angle and oil contact angle of the coating surface are The adjustment can be made by adjusting the amount of nanoparticle sol added, and the adjustment flexibility is relatively high. During the curing process of the coating made of the coating, the nano-silica particles modified by the silane coupling agent composition are strongly combined in the cross-linked network structure of the polymer formed by the curing of the polyurethane in a chemically bonded manner. The bonding force between the polyurethane coating and the plastic panel of the air conditioner or other household appliances is strengthened by hydrogen bonding, mechanical anchoring, and bonding between the silane coupling agent and the plastic panel. During the preparation and application of the coating, the curing process and the corresponding additives ensure that the mechanical properties and weather resistance of the coating can meet its daily use requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0031] Figure 1 This is a comparison test diagram of the water contact angle and the oil contact angle of the air conditioner ABS panel before and after coating with the coating in Example 1;

[0032] Figure 2 This is a weather resistance test result diagram of an air conditioner ABS panel after being coated with the coating in Example 1;

[0033] Figure 3 This is a diagram showing the cleaning test results of an air conditioner ABS panel after being coated with the coating in Example 1;

[0034] Figure 4 The test result diagram of each test in Table 2 after the air conditioner ABS panel was coated with the coating in Example 1;

[0035] Figure 5 is a process flow chart of the preparation of the nanoparticle sol in Example 1;

[0036] Figure 6 is a process flow chart for preparing the waterborne polyurethane resin prepolymer in Example 1;

[0037] Figure 7 This is a flow chart of the preparation process of the auxiliary agent component in Example 1.

[0038] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0041] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] The technical problem to be solved by the present application is: At present, the panel surfaces and interiors of air conditioners and other household appliances are easily stained with oil and other stains, and the oil and the panel have a strong adhesion. The oleophobicity of the coating on the traditional panel or inner surface is poor, resulting in the inability to easily remove the stained oil and other stains using conventional cleaning methods. Cleaning with strong alkaline detergents or high-hardness cleaning products such as steel wool can easily cause scratches, corrosion, etc., which affects the appearance of the air conditioner and causes great trouble to consumers.

[0043] In order to solve the above technical problems, a special coating is designed for the panels and inner surfaces of air conditioners and other household appliances that are easily contaminated with oil. The coating can form an easy-to-clean coating, effectively preventing stains such as oil from adhering to the surface of household appliances, making daily cleaning of household appliances such as air conditioners simpler and more convenient for consumers.

[0044] The invention provides a coating, which comprises a nano-particle sol and an aqueous polyurethane resin prepolymer; the nano-particle sol comprises the following raw materials in parts by weight: 1 to 3.5 parts of nano-silicon dioxide particles; 5 to 10 parts of a silane coupling agent composition; and 70 to 240 parts of a solvent; wherein the silane coupling agent composition comprises fluorosilane and a long-chain alkyl silane.

[0045] Specifically, the amount of nano-silica particles in the nano-particle sol of the present invention can be 1 part, 1.2 parts, 1.5 parts, 2 parts, 2.5 parts, 2.8 parts, 3 parts or 3.5 parts, whichever is within the above range.

[0046] Specifically, the amount of the silane coupling agent composition in the nanoparticle sol of the present invention can be 5 parts, 5.5 parts, 5.8 parts, 6 parts, 7 parts, 9 parts, 10 parts, and any amount within the above range can be used.

[0047] It should be noted that, compared with the modification of nano-silica particles by conventional silane coupling agents, the present invention uses multiple silane coupling agents in a silane coupling agent composition to jointly graft and modify nano-silica particles, and the silane coupling agent composition includes fluorosilane, long-chain alkyl silane, and alkenyl silane. The effects of the silane coupling agent composition are mainly reflected as follows:

[0048] First, the fluorosilane coupling agent enables the nano-silica particles to be grafted with fluorine-containing long-chain silane groups so that they have strong hydrophobic and oleophobic properties. Under the action of the water-based polyurethane resin prepolymer base material, the nano-silica particles grafted with fluorine-containing long-chain silane groups tend to diffuse to the surface of the coating, so that the coating has strong hydrophobic and oleophobic properties and easy-to-clean effects; in addition, the fluorine-containing long-chain silane groups in the present invention are perfluoroalkyl chains, which have excellent chemical stability and thermal stability, and enhance the corrosion resistance and thermal stability of the coating.

[0049] Second, the long-chain alkyl silane coupling agent can promote the dispersion of nano-silica particles in the waterborne polyurethane resin prepolymer base material; the long-chain alkyl group of the long-chain alkyl silane coupling agent also has strong hydrophobicity and oleophobicity, and also has a strengthening effect on the hydrophobicity and oleophobicity of the coating surface.

[0050] Third, the silane coupling agent composition also includes alkenyl long-chain silane, which has higher activity. The double bonds of the alkenyl long-chain silane can participate in free radical polymerization when the coating is cross-linked and cured, and react with the active groups in the waterborne polyurethane resin prepolymer base material or the plastic panel to form bonds, which can enhance the interfacial bonding force between the nano-silica particles and the waterborne polyurethane resin prepolymer base material, and can also increase the interfacial bonding force between the coating and the plastic panel of the household appliance, thereby improving the mechanical strength of the coating.

[0051] It should also be noted that the inventors have concluded through long-term research in the process of preparing the coating that the amount of the silane coupling agent composition in the nanoparticle sol has a great influence on the performance of the prepared coating. When the amount of the silane coupling agent composition is too small, the silane coupling agent grafted on the surface of the nano-silica particles is insufficient, and agglomeration effect is likely to occur, resulting in poor uniformity and stability of the silica sol, which affects the uniformity and stability of the coating, and easily leads to pinholes, bubbles or other defects in the coating, and also weakens the adhesion of the coating on the surface of the substrate. When the silane coupling agent composition is excessive, the excessive coupling agent will form a thicker organic layer at the interface between the nano-silica particles and the resin matrix, which will reduce the mechanical strength of the coating; at the same time, the excessive coupling agent contains more active groups, which will cause more hydrolysis reactions to occur, thereby accelerating the aging of the coating, and will also reduce the elasticity of the coating, causing the coating to crack; in addition, the use of excessive coupling agents will significantly increase production costs.

[0052] It should also be noted that the inventors have concluded through long-term research in the process of preparing the coating that the amount of nano-silica particles in the nano-particle sol also has a significant effect on the performance of the prepared coating. When the amount of nano-silica particles is too small, the proportion of fillers in the coating is significantly reduced, which seriously affects the functionality of the coating, significantly reduces its hydrophobic and oleophobic properties and mechanical properties, so that the silane coupling agent composition cannot exert the corresponding modification effect; when the nano-silica particles are excessive, agglomeration effects are prone to occur, and the nano-silica particles are prone to aggregation, thereby affecting the uniformity and stability of the coating, and easily causing pinholes, bubbles or other defects in the coating, which will also weaken the adhesion of the coating on the surface of the substrate and affect the service life of the coating.

[0053] In one embodiment, the fluorosilane includes at least one of perfluoroalkyl trimethoxysilane and perfluoroalkyl triethoxysilane. It should be noted that perfluoroalkyl trimethoxysilane is an important type of silane coupling agent, and its general chemical formula is (CF 3 (CF2 )n)Si(OCH 3 ) 3 , where n represents the length of the perfluoroalkyl chain. The perfluoroalkyl chain in perfluoroalkyltrimethoxysilane has extremely low surface energy, which can give the material surface excellent hydrophobicity and oleophobicity, and is suitable for oil-proof and antifouling applications; perfluoroalkyltrimethoxysilane has excellent chemical stability, can resist corrosion by most acids, alkalis and organic solvents, and is suitable for harsh chemical environments; perfluoroalkyltrimethoxysilane also has high thermal stability and can maintain its performance at high temperatures. As above, perfluoroalkyltriethoxysilane is also an important type of silane coupling agent, which has similar chemical properties to perfluoroalkyltrimethoxysilane, and the general chemical formula is (CF 3 (CF 2 ) n )Si(OC 2 H 5 ) 3 , where n represents the length of the perfluoroalkyl chain.

[0054] In one embodiment, the perfluoroalkyl trimethoxysilane comprises perfluorooctyl trimethoxysilane (1H,1H,2H,2H-Perfluorooctyl trimethoxysilane, chemical formula: 8 F 13 )-Si(OCH 3 ) 3 ), perfluorodecyltrimethoxysilane (1H,1H,2H,2H-Perfluorodecyltrimethoxysilane, chemical formula (C 10 F 17 )-Si(OCH 3 ) 3 ), perfluorotetradecyltrimethoxysilane (1H,1H,2H,2H-Perfluorotetradecyltrimethoxysilane, chemical formula (C 14 F 25 )-Si(OCH 3 ) 3 ), 1H,1H,2H,2H-Perfluorodecyltrimethoxysilane (C 17 F 31 )-Si(OCH 3 ) 3 ) at least one.

[0055] In one embodiment, the perfluoroalkyl triethoxysilane comprises perfluorooctyl triethoxysilane (1H,1H,2H,2H-Perfluorooctyltriethoxysilane, chemical formula: 8 F 13 )-Si(OC 2 H 5 ) 3 ), perfluorodecyltriethoxysilane (1H,1H,2H,2H-Perfluorodecyltriethoxysilane, chemical formula (C 10 F 17 )-Si(OC 2 H 5 ) 3 ), perfluorotetradecyltriethoxysilane (1H,1H,2H,2H-Perfluorotetradecyltriethoxysilane, chemical formula (C 14 F 25 )-Si(OC 2 H 5 ) 3 ), 1H,1H,2H,2H-Heptadecafluorodecyltriethoxysilane (C 17 F 31 )-Si(OC 2 H 5 ) 3 ) at least one.

[0056] In one embodiment, the long-chain alkyl silane includes at least one of long-chain alkyl trimethoxy silane and long-chain alkyl triethoxy silane. It should be noted that long-chain alkyl trimethoxy silane is a common silane coupling agent, and its general chemical formula is R-Si(OCH 3 ) 3 , wherein R represents a long-chain alkyl group; the carbon chain of the long-chain alkyl group of the long-chain alkylsilane in the present invention includes at least 8 carbon atoms. Long-chain alkyltrimethoxysilane is widely used in the fields of surface treatment, coatings, composite materials, etc., including hexadecyltrimethoxysilane (C 16 H 33 Si(OCH 3 ) 3 ), octadecyltrimethoxysilane (C 18 H 37 Si(OCH 3 ) 3) etc. Its long-chain alkyl group has the characteristics of low surface energy, hydrophobicity, oleophobicity, and excellent chemical stability. As mentioned above, long-chain alkyl triethoxysilane is also a common silane coupling agent, which has similar chemical properties to long-chain alkyl trimethoxysilane. The general chemical formula is R-Si(OC 2 H 5 ) 3 , wherein R represents a long-chain alkyl group; the long-chain alkyl group of the long-chain alkylsilane in the present invention has at least 8 carbon atoms in its carbon chain.

[0057] In one embodiment, the long-chain alkyl trimethoxysilane includes n-octyl trimethoxysilane (Octyltrimethoxysilane, chemical formula: 8 H 17 )-Si(OCH 3 ) 3 ), dodecyltrimethoxysilane (Dodecyltrimethoxysilane, chemical formula is (C 12 H 25 )-Si(OCH 3 ) 3 ), hexadecyltrimethoxysilane (Hexadecyltrimethoxysilane, chemical formula (C 16 H 33 )-Si(OCH 3 ) 3 ), Octadecyltrimethoxysilane (Octadecyltrimethoxysilane, chemical formula (C 18 H 37 )-Si(OCH 3 ) 3 ), docosyltrimethoxysilane (Docosyltrimethoxysilane, chemical formula is (C 22 H 45 )-Si(OCH 3 ) 3 ) at least one.

[0058] In one embodiment, the long-chain alkyl triethoxysilane includes n-octyl triethoxysilane (Triethoxyoctylsilane, chemical formula: 8 H 17 )-Si(OC 2 H 5 ) 3 ), dodecyltriethoxysilane (Dodecyltriethoxysilane, chemical formula (C 12 H 25 )-Si(OC2 H 5 ) 3 ), hexadecyltriethoxysilane (Hexadecyltriethoxysilane, chemical formula (C 16 H 33 )-Si(OC 2 H 5 ) 3 ), Octadecyltriethoxysilane (Octadecyltriethoxysilane, chemical formula (C 18 H 37 )-Si(OC 2 H 5 ) 3 ), docosyltriethoxysilane (Docosyltriethoxysilane, chemical formula is (C 22 H 45 )-Si(OC 2 H 5 ) 3 ) at least one.

[0059] In one embodiment, the silane coupling agent composition further comprises alkenyl silane. It should be noted that alkenyl silane is an organic silicon compound containing a carbon-carbon double bond structure, and in a free radical polymerization reaction, alkenyl silane can participate in the reaction as a functional monomer, thereby introducing a siloxane group into a polymer chain, giving the polymer corresponding physical or chemical properties.

[0060] It should also be noted that in the present invention, the nano-silica particles are modified by using alkenyl silanes, and the alkenyl silane groups are grafted onto the surface of the nano-silica particles. The alkenyl silane groups disperse the nano-silica particles and strongly bind them in the cross-linked network structure of the polymer formed by curing of the polyurethane in a chemically bonded manner, which is beneficial to improving the mechanical strength and hydrophobic and oleophobic properties of the coating.

[0061] In one embodiment, the alkenyl silane includes vinyltrimethoxysilane (vinyltrimethoxysilane, chemical formula: 2 H 3 )-Si(OCH 3 ) 3 ), Vinyltriethoxysilane (Vinyltriethoxysilane, chemical formula (C 2 H 3 )-Si(OC 2 H 5 ) 3 ), Propyltrimethoxysilane (Propyltrimethoxysilane, chemical formula (C3 H 5 )-Si(OCH 3 ) 3 )), Triethoxyvinylsilane (Triethoxyvinylsilane, chemical formula (C 3 H 5 )-Si(OC 2 H 5 ) 3 ), 5-Hexenyltrimethoxysilane (5-Hexenyltrimethoxysilane, chemical formula (C 6 H 11 )-Si(OCH 3 ) 3 ), 5-Hexenyltriethoxysilane (5-Hexenyltriethoxysilane, chemical formula (C 6 H 11 )-Si(OC 2 H 5 ) 3 ), 7-octenyltrimethoxysilane (7-Octenyltrimethoxysilane, chemical formula (C 8 H 15 )-Si(OCH 3 ) 3 ), 7-octenyltriethoxysilane (7-Octenyltriethoxysilane, chemical formula (C 8 H 15 )-Si(OC 2 H 5 ) 3 ), 10-dodecenyltrimethoxysilane (10-Dodecenyltrimethoxysilane, chemical formula (C 12 H 23 )-Si(OCH 3 ) 3 ), 10-dodecenyltriethoxysilane (10-Dodecenyltriethoxysilane, chemical formula (C 12 H 23 )-Si(OC 2 H 5 ) 3 ), 18-octadecenyltrimethoxysilane (18-Octadecenyltrimethoxysilane, chemical formula (C 18 H 35 )-Si(OCH 3 ) 3), 18-octadecenyltriethoxysilane (18-Octadecenyltriethoxysilane, chemical formula (C 18 H 35 )-Si(OC 2 H 5 ) 3 ), 3-Methacryloxypropyltrimethoxysilane (3-Methacryloxypropyltrimethoxysilane, chemical formula (C 7 H 11 O 2 )-Si(OCH 3 ) 3 ), 3-Methacryloxypropyltriethoxysilane (3-Methacryloxypropyltriethoxysilane, chemical formula (C 7 H 11 O 2 )-Si(OC 2 H 5 ) 3 ) at least one.

[0062] In one embodiment, in the silane coupling agent composition, the weight ratio of the fluorosilane, long-chain alkyl silane and alkenyl silane is (3-5): (1-3): (1-2). Preferably, in the silane coupling agent composition, the weight ratio of the fluorosilane, long-chain alkyl silane and alkenyl silane is 3:2:1.

[0063] It should be noted that the inventors prepared different coatings and formed coatings by controlling the ratio of multiple silane coupling agents in the silane coupling agent composition, and measured various properties of the coatings such as the hydrophobic angle and the oleophobic angle, and obtained that the above ratio is a reasonable numerical range for the weight ratio of fluorosilane, long-chain alkyl silane and alkenyl silane in the silane coupling agent composition.

[0064] It should be noted that the nano-silica particles, as fillers of the coating of the present invention, play an important role in the mechanical strength of the coating formed by the coating. The type and particle size of the nano-silica particles have a significant effect on the mechanical strength, dispersion and flatness of the coating formed by the coating.

[0065] Optionally, the particle size of the nano-silicon dioxide particles is 1 nm to 100 nm; it is understandable that the particle size of the nano-silicon dioxide particles may be 20 to 50 nm, or 50 to 80 nm; preferably, the particle size of the nano-silicon dioxide particles is 20 to 50 nm.

[0066] It should be noted that the nano-silica particles are the main filler of the coating of the present invention, and the particle size has an important influence on the performance of the coating. If the particle size of the nano-silica particles is too small, the specific surface area will be too large, and it is easy to agglomerate. Even if a silane coupling agent is used to improve its dispersibility, it is still difficult to avoid agglomeration with a small particle size; if the particle size is too small, the mechanical properties of the coating will decrease, and particles with too small a particle size cannot effectively enhance the network structure of the matrix resin; in addition, if the specific surface area is too large, there will be more active sites exposed to the outside, making it more susceptible to hydrolysis, accelerating the aging speed of the coating, and significantly reducing weather resistance and water resistance. If the particle size of the nano-silica particles is too large, the specific surface area will be too small, so that the grafting rate of the silane coupling agent on the surface of the nano-silica particles is too low, so that the silane coupling agent composition cannot play a corresponding modification effect, so that its hydrophobic and oleophobic properties and mechanical properties cannot achieve the expected technical effects; if the particle size is too large, the viscosity of the coating will be weakened, causing the coating to become thinner, difficult to apply evenly or have a significant sense of grain, and the occurrence of coating defects such as sagging and shrinkage. Therefore, within the above-mentioned particle size range, the nano-silicon dioxide particles can be dispersed in the preparation raw materials more evenly, and the surface of the prepared coating is smooth without affecting other properties.

[0067] In one embodiment, in the nanoparticle sol, the weight ratio of the fluorosilane to the nano-silica particles is (3-5):1. It is understandable that in the nanoparticle sol, the weight ratio of the fluorosilane to the nano-silica particles can be 3:1, 3.1:1, 3.5:1, 4:1, or 5:1, whichever is in line with the above ratio range. By reasonably controlling the weight ratio of the fluorine modifier to the base filler to adjust the hydrophobic angle and oleophobic angle of the coating surface, the coating can effectively prevent pollutants such as oil from adhering to the surface of household appliances such as air conditioners, and is easy to clean. Among them, excessive fluorosilane will affect the adhesion of nano-silica particles to the matrix resin, thereby affecting the adhesion of the coating to the surface of the substrate; excessive fluorinated silane coupling agent will also cause the coating to become too rigid, reduce its flexibility and impact resistance, and easily cause brittle cracking, peeling and other problems.

[0068] In one embodiment, the waterborne polyurethane resin prepolymer includes the following raw materials in parts by weight: 20 to 40 parts of bio-based polyether diol, 20 to 40 parts of isocyanate, 0.6 to 0.9 parts of catalyst, 2 to 5 parts of end-capping agent, 2 to 5 parts of functional additive, 0.02 to 0.04 parts of organic acid, 0.01 to 0.03 parts of inorganic acid, 0.01 to 0.04 parts of antioxidant, and 10 to 20 parts of deionized water.

[0069] It should be noted that the waterborne polyurethane resin prepolymer in the present invention, as the base material of the coating, directly determines many basic performance indicators of the coating, such as mechanical strength and weather resistance; the bio-based polyether diol is selected as the main raw material to make the coating have better affinity with human skin; optionally, the number average molecular weight of the bio-based polyether diol in the present invention is 1500-3000; preferably, the number average molecular weight of the bio-based polyether diol in the present invention is 2000; the present invention does not impose specific restrictions on the specific type of the catalyst.

[0070] It should also be noted that the end-capping agent in the present invention is mainly used to terminate the polymerization reaction and control the molecular weight during the synthesis of the waterborne polyurethane resin prepolymer; preferably, the end-capping agent in the present invention has a carbon-carbon double bond or other active groups, which can undergo other reactions such as cross-linking polymerization during subsequent processing.

[0071] In a preferred embodiment, the waterborne polyurethane resin prepolymer comprises the following raw materials in parts by weight: 20 to 40 parts of bio-based polyether diol, 30 to 60 parts of isocyanate, 0.002 to 0.006 parts of catalyst, 0.02 to 0.04 parts of end-capping agent, 5 to 10 parts of functional additive, 0.02 to 0.04 parts of organic acid, 0.01 to 0.02 parts of inorganic acid, 0.01 to 0.04 parts of antioxidant, and 200 to 300 parts of deionized water.

[0072] It should be noted that, by adopting the above ratio, the mechanical strength, weather resistance and other basic performance indicators of the coating have better performance. In one embodiment, in the waterborne polyurethane resin prepolymer, the functional additive includes at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid and dihydroxybenzoic acid. It should be noted that the functional additive in the present invention can be used as a chain terminator in the synthesis process of the waterborne polyurethane resin prepolymer to accurately control the molecular weight of the waterborne polyurethane resin prepolymer, so that the uniformity, mechanical strength and other properties of the coating have better performance.

[0073] In one embodiment, the coating further includes an auxiliary component; the auxiliary component includes the following raw materials in parts by weight: 0.5 to 10 parts of defoaming agent, 1 to 10 parts of light stabilizer, 0.5 to 5 parts of leveling agent, 10 to 50 parts of matting agent, 3 to 5 parts of acrylate compound, 30 to 60 parts of organic solvent, and 20 to 50 parts of deionized water.

[0074] It should be noted that, in the present invention, the synergistic effect of the light stabilizer and the ultraviolet absorber is used to significantly improve the anti-ultraviolet aging performance of the coating, and prevent the coating from fading, cracking, etc. when exposed to sunlight for a long time; the surface flatness of the coating is improved by the leveling agent, and the defoaming agent eliminates bubbles in the coating, thereby enhancing the spreadability and uniformity of the coating, thereby obtaining a high-quality coating surface; the present invention does not make specific restrictions on defoaming agents, light stabilizers, leveling agents, and matting agents; preferably, the acrylate compounds include butyl acrylate and methyl methacrylate, and the addition of butyl acrylate to the auxiliary component is beneficial to enhancing the weather resistance and corrosion resistance of the coating.

[0075] In one embodiment, in the coating, the weight ratio of the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary component is (50-70): (20-30): (10-20). Preferably, the weight ratio of the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary component is 7:2:1.

[0076] It should be noted that by controlling the amount of nanoparticle sol, water-based polyurethane resin prepolymer and auxiliary components within the above range, the prepared coating has good hydrophobicity and oleophobicity, is easier to clean, and the coating also has good wear resistance and weather resistance as well as high hardness; when the nanoparticle sol is excessive, the proportion of filler in the coating is too high, and the adhesion of the base resin is insufficient, which will affect the adhesion between the coating and the substrate surface; when the amount of nanoparticle sol is insufficient, the hydrophobic and oleophobic properties of the coating cannot achieve the expected technical effect.

[0077] The present invention also provides a method for preparing the coating, which specifically comprises the following steps:

[0078] S10, dispersing nano-silica particles in a solvent, adjusting the pH to alkaline, adding a silane coupling agent composition to react, adjusting the pH to neutral or weakly acidic, allowing the solvent to stand, filtering and collecting the filtrate to obtain a nano-particle sol;

[0079] S20, mixing the waterborne polyurethane resin prepolymer and the nanoparticle sol prepared in step S10 according to a proportion to prepare the coating.

[0080] It should be noted that, in step S10 of the present invention, an alkaline catalyst is used to adjust the pH to alkaline, so that the silane coupling agent composition undergoes a hydrolysis reaction, and then an acid is used for neutralization to obtain a modified nano-silica particle sol.

[0081] In one embodiment, between step S10 and step S20, the following steps are further included:

[0082] S11: vacuum dehydrating the bio-based polyether diol at 35-65° C., then adding deionized water, isocyanate, functional additives, catalysts, organic acids and inorganic acids, stirring and reacting at 65-75° C. to obtain a polyurethane prepolymer, then adding a capping agent and stirring and reacting, adjusting the pH to neutral, and obtaining a waterborne polyurethane resin prepolymer;

[0083] S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, an acrylate compound, an organic solvent and deionized water, and filtering the filtrate to obtain an auxiliary agent component.

[0084] In one embodiment, in the step S20, the nanoparticle sol prepared in the step S10, the waterborne polyurethane resin prepolymer prepared in the step S11 and the auxiliary component prepared in the step S12 are mixed according to a proportion to prepare the coating.

[0085] It can be understood that in the preparation process of the coating of the present invention, the preparation processes of the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary agent component are all independent preparation processes, and the order of the three is not distinguished.

[0086] It can be understood that in step S20, the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary component are only blended in a physical sense.

[0087] The present invention also provides a household appliance, wherein the household appliance uses the coating.

[0088] In a specific embodiment, the household appliance includes an air conditioner, and the coating forms a hydrophobic and oleophobic coating on the panel surface of the air conditioner through a thermal cross-linking and curing process.

[0089] In a specific embodiment, the household appliance can also be a microwave oven, an induction cooker, an oven, a bread maker, a noodle maker, a range hood, an air blast cooker, a pancake rack, a humidifier, an electric kettle, a hair dryer, a juicer, a pressure cooker, an electric rice cooker, a water heater, a computer, an electric fan, an electric frying pan, a soy milk maker, a speaker, a stove, or a refrigerator, etc.

[0090] In a specific embodiment, the coating is applied to a housing panel of the above-mentioned household appliance.

[0091] It can be understood that the raw materials used to prepare the coating are not substances restricted or prohibited by domestic and international laws and regulations, and no harmful substances are generated during the preparation process of the coating, so that the coating and household appliances are both safe and environmentally friendly.

[0092] The present invention is further described below by means of specific embodiments:

[0093] The present invention does not impose any specific restrictions on the source of raw materials. The sources of raw materials in each embodiment of the present invention are as follows:

[0094] 1H,1H,2H,2H-Perfluorotetradecyl)tri(ethoxy)silane, CAS No.: 885275-56-9;

[0095] 1H,1H,2H,2H-Perfluorooctyltriethoxysilane, CAS No.: 51851-37-7;

[0096] 1H,1H,2H,2H-Perfluoroheptadecantrimethyloxysilane, CAS No.: 101947-16-4;

[0097] n-Octyltriethoxysilane, CAS No.: 2943-75-1;

[0098] Dodecyltriethoxysilane, CAS No.: 18536-91-9;

[0099] Octadecyltriethoxysilane, CAS number: 7399-00-0;

[0100] 5-Hexenyltriethoxysilane, CAS No.: 52034-14-7;

[0101] Behenyltriethoxysilane, CAS number: 330457-44-8;

[0102] Hydroxyethyl acrylate, CAS No.: 818-61-1;

[0103] Hydroxyethyl methacrylate, CAS No.: 868-77-9;

[0104] Hydroxypropyl methacrylate, CAS No.: 27813-02-1;

[0105] Butyl acrylate, CAS number: 141-32-2;

[0106] Methyl methacrylate, CAS number: 80-62-6;

[0107] Polytrimethylene ether glycol (PO3G) (number average molecular weight 2000), CAS number: 345260-48-2;

[0108] Antioxidant (1010), the main component is pentaerythritol tetra(3,5-di-tert-butyl-4-hydroxyhydrocinnamate), CAS number: 6683-19-8;

[0109] Defoamer PS-613, composed of polyorganosiloxane, modified polysiloxane, silicon dioxide, special polyether hydroxyl compound, synergist, etc.;

[0110] Light stabilizer (ultraviolet absorber UVP-327), the main component is 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, CAS No.: 3864-99-1;

[0111] Leveling agent( Glide 450) is a polyether siloxane copolymer;

[0112] Matting agent (OK-520) is medium-sized precipitated silica treated with wax;

[0113] 4,4'-Dicyclohexylmethane diisocyanate, CAS No.: 5124-30-1;

[0114] Dibutyltin dilaurate, CAS number: 77-58-7;

[0115] Dimethylolpropionic acid, CAS number: 4767-03-7;

[0116] Triethylamine, CAS number: 121-44-8;

[0117] Phosphoric acid, CAS number: 7664-38-2;

[0118] Malic acid, CAS number: 617-48-1.

[0119] Example 1

[0120] The invention provides preparation raw materials, which include, by weight, 1.5 parts of nano-silica powder, 20 parts of ethanol, 40 parts of ethylene glycol, 5 parts of isopropanol, 5 parts of water, 5 parts of (1H, 1H, 2H, 2H-perfluorotetradecyl) tri(ethoxy) silane, 1.5 parts of n-octyltriethoxysilane, 1 part of 5-hexenyltriethoxysilane, an appropriate amount of a mixed alkaline catalyst of sodium hydroxide, concentrated ammonia water and sodium ethoxide in a mass ratio of 1:1:1, and an appropriate amount of ammonium chloride solution.

[0121] The preparation raw materials are provided. The preparation raw materials of the waterborne polyurethane resin prepolymer include, by weight: 30 parts of polytrimethylene ether glycol (PO3G, number average molecular weight is 2000), 15 parts of deionized water, 40 parts of 4,4'-dicyclohexylmethane diisocyanate (HMDI), 4.5 parts of 2-(hydroxymethyl)propionic acid (DMPA), 0.7 parts of dibutyltin dilaurate (DBTDL), 0.01 parts of phosphoric acid, 0.02 parts of malic acid, 3 parts of hydroxyethyl acrylate, and an appropriate amount of triethylamine.

[0122] Provide preparation raw materials, by weight, the preparation raw materials of the auxiliary component include: 5 parts of defoamer (PS-613), 5 parts of light stabilizer (UVP-327), 5 parts of leveling agent ( Glide 450) 2 parts, matting agent (OK-520) 10 parts, methyl methacrylate (MMA) 3 parts, ethanol 40 parts, deionized water 30 parts.

[0123] The preparation process of the coating in Example 1 comprises the following steps:

[0124] S10, mixing the ground nano-silica (average particle size of 20-80 nm) with ethanol, ethylene glycol, isopropanol and water, stirring at 800 rpm at 45°C for 1 hour until the solution is evenly mixed; adding an appropriate amount of alkaline catalyst to adjust the pH to 10, stirring at 800 rpm at 45°C for 2 hours; then adding (1H, 1H, 2H, 2H-perfluorotetradecyl) tri(ethoxy)silane, n-octyltriethoxysilane and 5-hexenyltriethoxysilane, stirring at 800 rpm at 50°C for 3 hours, adding an appropriate amount of ammonium chloride to adjust the pH to 6, standing for 0.5 hours, filtering with a 200-mesh filter to remove insoluble impurities, and obtaining a nanoparticle sol;

[0125] S11, dehydrating polytrimethylene ether glycol at 110° C. for 1 h in vacuum, cooling to 70° C., adding deionized water, 4,4'-dicyclohexylmethane diisocyanate, 2-(hydroxymethyl)propionic acid, dibutyltin dilaurate, phosphoric acid, and malic acid to the polytrimethylene ether glycol, stirring at 800 rpm for 2 h at 70° C. to obtain a polyurethane prepolymer; adding hydroxyethyl acrylate to the polyurethane prepolymer, stirring at 800 rpm for 1 h, neutralizing with triethylamine to pH 7, and obtaining a waterborne polyurethane resin prepolymer;

[0126] S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, methyl methacrylate and ethanol, stirring at a speed of 200 rpm for 1 hour, adding deionized water, stirring at a speed of 100 rpm for 1 hour, and filtering with a 200-mesh filter to obtain an auxiliary agent component;

[0127] S20, mixing the nanoparticle sol, waterborne polyurethane resin prepolymer and auxiliary component prepared in the above step in a weight ratio of 7:2:1 at a speed of 500 rpm for 10 minutes to obtain a coating.

[0128] Example 2

[0129] The invention provides preparation raw materials, which include, by weight, 3.5 parts of nano silicon dioxide powder, 90 parts of ethanol, 90 parts of ethylene glycol, 50 parts of isopropanol, 10 parts of water, 4.5 parts of 1H,1H,2H,2H-perfluorooctyltriethoxysilane, 3 parts of dodecyltriethoxysilane, 2.5 parts of docosyltriethoxysilane, an appropriate amount of a mixed alkaline catalyst of sodium hydroxide, concentrated ammonia water and sodium ethoxide in a mass ratio of 1:1:1, and an appropriate amount of ammonium chloride.

[0130] Providing preparation raw materials, the preparation raw materials of the waterborne polyurethane resin prepolymer include, by weight: 20 parts of polytrimethylene ether glycol (PO3G, number average molecular weight is 2000), 15 parts of deionized water, 25 parts of 4,4'-dicyclohexylmethane diisocyanate (HMDI), 3 parts of 2-(hydroxymethyl)propionic acid (DMPA), 0.7 parts of dibutyltin dilaurate (DBTDL), 0.01 parts of phosphoric acid, 0.02 parts of malic acid, 3 parts of hydroxyethyl methacrylate, and an appropriate amount of triethylamine.

[0131] Provide preparation raw materials, by weight, the preparation raw materials of the auxiliary component include: 2 parts of defoamer (PS-613), 5 parts of light stabilizer (UVP-327), leveling agent ( Glide 450) 3 parts, matting agent (OK-520) 3 parts, butyl acrylate (BA) 2 parts, ethanol 40 parts, deionized water 30 parts.

[0132] The preparation process of the coating in Example 2 comprises the following steps:

[0133] S10, mixing the ground nano-silica (average particle size of 20-80 nm) with ethanol, ethylene glycol, isopropanol and water, stirring at 800 rpm at 50°C for 2 h until the solution is uniformly mixed; adding an appropriate amount of alkaline catalyst to adjust the pH to 9, stirring at 800 rpm at 45°C for 2 h; then adding 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane, dodecyltriethoxysilane and docosyltriethoxysilane, stirring at 800 rpm at 50°C for 3 h, adding an appropriate amount of ammonium chloride to adjust the pH to 6, standing for 0.5 h, filtering with a 200-mesh filter to remove insoluble impurities, and obtaining a nanoparticle sol;

[0134] S11, dehydrating polytrimethylene ether glycol at 110° C. for 1 h in vacuum, cooling to 70° C., adding deionized water, 4,4'-dicyclohexylmethane diisocyanate, 2-(hydroxymethyl)propionic acid, dibutyltin dilaurate, phosphoric acid and malic acid to polytrimethylene ether glycol, stirring and reacting at 800 rpm at 70° C. for 2 h to obtain a polyurethane prepolymer; adding hydroxyethyl methacrylate to the polyurethane prepolymer, stirring and reacting at 800 rpm for 1 h, neutralizing with triethylamine to pH 7, and obtaining a waterborne polyurethane resin prepolymer;

[0135] S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, butyl acrylate and ethanol, stirring at a speed of 200 rpm for 1 hour, adding deionized water, stirring at a speed of 100 rpm for 1 hour, and filtering with a 200-mesh filter to obtain an auxiliary agent component;

[0136] S20, mixing the nanoparticle sol, waterborne polyurethane resin prepolymer and auxiliary component prepared in the above step in a weight ratio of 5:2:1 at a speed of 500 rpm for 10 minutes to obtain a coating.

[0137] Example 3

[0138] The invention provides preparation raw materials, which include, by weight, 1 part of nano-silica powder, 60 parts of ethanol, 60 parts of ethylene glycol, 20 parts of isopropanol, 7 parts of water, 3 parts of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, 1 part of octadecyltriethoxysilane, 1 part of 5-hexenyltriethoxysilane, an appropriate amount of a mixed alkaline catalyst of sodium hydroxide, concentrated ammonia water and sodium ethoxide in a mass ratio of 1:1:1, and an appropriate amount of ammonium chloride.

[0139] Providing preparation raw materials, the preparation raw materials of the waterborne polyurethane resin prepolymer include, by weight: 40 parts of polytrimethylene ether glycol (PO3G, number average molecular weight is 2000), 15 parts of deionized water, 20 parts of 4,4'-dicyclohexylmethane diisocyanate (HMDI), 2 parts of 2-(hydroxymethyl)propionic acid (DMPA), 0.7 parts of dibutyltin dilaurate (DBTDL), 0.01 parts of phosphoric acid, 0.02 parts of malic acid, 3 parts of hydroxypropyl methacrylate, and an appropriate amount of triethylamine.

[0140] Provide preparation raw materials, by weight, the preparation raw materials of the auxiliary component include: defoamer (PS-613) 10 parts, light stabilizer (UVP-327) 10 parts, leveling agent ( Glide 450) 5 parts, matting agent (OK-520) 5 parts, butyl acrylate (BA) 3 parts, ethanol 40 parts, deionized water 30 parts.

[0141] The preparation process of the coating in Example 3 comprises the following steps:

[0142] S10, mixing the ground nano-silicon dioxide (average particle size of 20-80 nm) with ethanol, ethylene glycol, isopropanol and water, stirring at 800 rpm at 45°C for 1 hour until the solution is evenly mixed; adding an appropriate amount of alkaline catalyst to adjust the pH to 12, stirring at 800 rpm at 45°C for 2 hours; then adding 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane, octadecyltriethoxysilane and 5-hexenyltriethoxysilane, stirring at 800 rpm at 50°C for 6 hours, adding an appropriate amount of ammonium chloride to adjust the pH to 6.5, standing for 1 hour, filtering with a 200-mesh filter to remove insoluble impurities, and obtaining a nanoparticle sol;

[0143] S11, dehydrating polytrimethylene ether glycol at 110° C. for 1 h in vacuum, cooling to 70° C., adding deionized water, 4,4'-dicyclohexylmethane diisocyanate, 2-(hydroxymethyl)propionic acid, dibutyltin dilaurate, phosphoric acid, and malic acid to the polytrimethylene ether glycol, stirring at 800 rpm for 2 h at 70° C. to obtain a polyurethane prepolymer; adding hydroxypropyl methacrylate to the polyurethane prepolymer, stirring at 800 rpm for 1 h, neutralizing with triethylamine to a pH of 7, and obtaining a waterborne polyurethane resin prepolymer;

[0144] S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, butyl acrylate and ethanol, stirring at a speed of 200 rpm for 1 hour, adding deionized water, stirring at a speed of 100 rpm for 1 hour, and filtering with a 200-mesh filter to obtain an auxiliary agent component;

[0145] S20, mixing the nanoparticle sol, waterborne polyurethane resin prepolymer and auxiliary component prepared in the above step in a weight ratio of 7:3:2 at a speed of 500 rpm for 10 minutes to obtain a coating.

[0146] Performance testing:

[0147] The coatings prepared in Example 1 and Example 2 were sprayed onto the surface of the ABS plastic panel respectively, the spraying pressure was controlled to be 4-5 bar, the spraying distance was controlled to be 50 cm, the paint mist was ensured to be evenly distributed during the spraying process, sagging and orange peel phenomenon were avoided, and the coating thickness was controlled to be about 100 microns; after spraying, it was dried at room temperature for about 2 hours until the surface was dry, and thermally cross-linked and cured at about 65°C for 2 hours to obtain the coatings corresponding to the coatings in Example 1 and Example 2 respectively.

[0148] (1) Hydrophobic and oleophobic performance test: The water contact angle and oil contact angle of the coating obtained in Example 1 and the ABS plastic panel were measured respectively. The measurement results are shown in Figure 1 ;

[0149] (2) Weather resistance test: The test was conducted in accordance with the provisions of the national standard GB / T14522, and the rating was conducted in accordance with the national standard GB / T1766. The QUV test lasted for 200 hours, using a UV-B light source with a wavelength of 280 to 315 nm, ultraviolet exposure for 8 hours, a temperature of 60°C ± 3°C, condensation for 4 hours, and a black mark temperature of 50°C ± 3°C. One cycle lasted for 12 hours. The coating prepared in Example 1 was coated on matte and high-gloss air-conditioning ABS plastic panels to form a coating, and then an aging test was conducted for 408 hours in total for 34 cycles in accordance with the above test standards. The color difference and gloss loss rate before and after were measured. At the same time, the uncoated air-conditioning ABS plastic panel was used as a control group. The measurement results are shown in Table 1. Figure 2 ;

[0150] (3) Cleanability test: Select an area of ​​about 4 cm in length and width at any position of the corresponding coating of the coating prepared in Example 1. Use an oil-based marker to fill the drawn area. Let the writing stand for 20 seconds, wipe it clean with a dust-free cloth moistened with water, and after the surface is dry, check the wiped area; at the same time, use an uncoated air conditioner ABS plastic windshield as a control group, and the test results are shown in Figure 2. Figure 3 ( Figure 3 1, 2, 3, 4, and 5 represent different types of marker pens);

[0151] (4) The various properties of the coatings prepared from the coatings in Example 1 and Example 2 were measured by referring to the measuring methods in Table 1; the coatings prepared from the coating in Example 1 were tested for water resistance, thermal shock resistance (i.e., thermal cycling test in Table 1), humidity and heat resistance, hot water immersion resistance, and resistance to wiping with neutral detergent. Figure 4 .

[0152] Depend on Figure 1 It can be seen that the water contact angle of the uncoated air conditioner ABS panel is 80.405°, and the oil contact angle is 34.169°; after the coating prepared in Example 1 is used to form a coating on the ABS panel, the water contact angle is 105.814°, and the oil contact angle is 83.183°. Comparing the above results, it can be seen that after the coating of the present invention is used to form a coating on the air conditioner panel, the hydrophobic and oleophobic properties are greatly improved.

[0153] Depend on Figure 2 It can be seen that Figure 2 There are 3 air-conditioning panels, the upper air-conditioning panel has no coating. After testing, the color difference ΔE is 36.9 compared with the case without aging test; the lower left air-conditioning panel is a matte air-conditioning panel with a coating formed by the coating prepared in Example 1. Compared with the case without aging test, the color difference ΔE is 1.83 and the light loss rate is 4.1%; the lower left air-conditioning panel is a high-gloss air-conditioning panel with a coating formed by the coating prepared in Example 1. Compared with the case without aging test, the color difference ΔE is 1.75 and the light loss rate is 6.3%. Comparing the above results, it can be obtained that after the coating of the present invention is used to form a coating on the air-conditioning panel, the weather resistance of the air-conditioning panel is greatly improved.

[0154] Depend on Figure 3 It can be seen that Figure 3There are 6 panels from left to right in the figure, one panel on the left is uncoated, and the 5 panels on the right are all panels coated with the coating prepared in Example 1. After being applied and wiped with 5 different types of oil-based pens, the handwriting on the coated panels can be wiped clean, while only a few handwriting on the uncoated panels can be wiped clean. By comparing the above results, it can be obtained that after the coating of the present invention is used to form a coating on the air-conditioning panel, the oleophobic performance of the air-conditioning panel is greatly improved, and the cleaning effect is significantly better.

[0155] Table 1

[0156]

[0157]

[0158] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A coating, characterized in that: The coating comprises nanoparticle sol and waterborne polyurethane resin prepolymer; The nanoparticle sol comprises the following raw materials in parts by weight: Nano silicon dioxide particles: 1 to 3.5 parts; Silane coupling agent composition: 5 to 10 parts; Solvent: 70-240 parts; Wherein, the silane coupling agent composition comprises fluorosilane and long-chain alkyl silane.

2. The coating according to claim 1, characterized in that The fluorosilane includes at least one of perfluoroalkyltrimethoxysilane and perfluoroalkyltriethoxysilane.

3. The coating according to claim 2, characterized in that The perfluoroalkyltrimethoxysilane includes at least one of perfluorooctyltrimethoxysilane, perfluorodecyltrimethoxysilane, perfluorotetradecyltrimethoxysilane and perfluoroheptadecanyltrimethoxysilane; And / or, the perfluoroalkyltriethoxysilane includes at least one of perfluorooctyltriethoxysilane, perfluorodecyltriethoxysilane, perfluorotetradecyltriethoxysilane and perfluoroheptadecantriethoxysilane.

4. The coating according to claim 1, characterized in that The long-chain alkylsilane includes at least one of long-chain alkyltrimethoxysilane and long-chain alkyltriethoxysilane.

5. The coating according to claim 4, characterized in that The long-chain alkyltrimethoxysilane includes at least one of n-octyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane and behenyltrimethoxysilane; And / or, the long-chain alkyltriethoxysilane includes at least one of n-octyltriethoxysilane, dodecyltriethoxysilane, hexadecyltriethoxysilane, octadecyltriethoxysilane and docosyltriethoxysilane.

6. The coating according to claim 1, characterized in that The silane coupling agent composition further comprises alkenyl silane.

7. The coating according to claim 6, characterized in that The alkenyl silane includes at least one of vinyltrimethoxysilane, vinyltriethoxysilane, acryltrimethoxysilane, acryltriethoxysilane, 5-hexenyltrimethoxysilane, 5-hexenyltriethoxysilane, 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, 10-dodecenyltrimethoxysilane, 10-dodecenyltriethoxysilane, 18-octadecenyltrimethoxysilane, 18-octadecenyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, and 3-methacryloxypropyltriethoxysilane.

8. The coating according to claim 6, characterized in that In the silane coupling agent composition, the weight ratio of the fluorosilane, the long-chain alkyl silane and the alkenyl silane is (3-5): (1-3): (1-2).

9. The coating according to claim 1, characterized in that In the nanoparticle sol, the weight ratio of the fluorosilane to the nano-silica particles is (3-5):

1.

10. The coating according to claim 1, characterized in that The waterborne polyurethane resin prepolymer comprises the following raw materials in parts by weight: Bio-based polyether diol: 20-40 parts; Isocyanate: 20-40 parts; Catalyst: 0.6-0.9 parts; Capping agent: 2-5 parts; 2 to 5 parts of functional additives; Organic acid: 0.02-0.04 parts; Inorganic acid: 0.01-0.03 parts; Antioxidant: 0.01-0.04 parts; Deionized water: 10-20 parts.

11. The coating material according to claim 10, characterized in that In the waterborne polyurethane resin prepolymer, the functional additive includes at least one of 2,2-dimethylol propionic acid, 2,2-dimethylol butyric acid, and dihydroxybenzoic acid.

12. The coating according to claim 1, characterized in that The coating also includes an auxiliary component; The auxiliary component comprises the following raw materials in parts by weight: Defoaming agent: 0.5-10 parts; Light stabilizer: 1-10 parts; Leveling agent: 0.5-5 parts; Matting agent: 10-50 parts; Acrylate compound: 3-5 parts; Organic solvent: 30-60 parts; Deionized water: 20-50 parts.

13. The coating according to claim 1, characterized in that In the coating, the weight ratio of the nanoparticle sol, the waterborne polyurethane resin prepolymer and the auxiliary component is (50-70): (20-30): (10-20).

14. A method for preparing a coating according to any one of claims 1 to 13, characterized in that: The preparation method of the coating comprises the following steps: S10, dispersing nano-silica particles in a solvent, adjusting the pH to alkaline, adding a silane coupling agent composition to react, adjusting the pH to neutral or weakly acidic, allowing the solvent to stand, filtering and collecting the filtrate to obtain a nano-particle sol; S20, mixing the waterborne polyurethane resin prepolymer and the nanoparticle sol prepared in step S10 according to a proportion to prepare the coating.

15. The method for preparing a coating according to claim 14, characterized in that: The steps S10 and S20 also include: S11: vacuum dehydrating the bio-based polyether diol at 35-65° C., then adding deionized water, isocyanate, functional additives, catalysts, organic acids and inorganic acids, stirring and reacting at 65-75° C. to obtain a polyurethane prepolymer, then adding a capping agent and stirring and reacting, adjusting the pH to neutral, and obtaining a waterborne polyurethane resin prepolymer; S12, mixing a defoamer, a light stabilizer, a leveling agent, a matting agent, an acrylate compound, an organic solvent and deionized water, and filtering the filtrate to obtain an auxiliary agent component.

16. The method for preparing a coating according to claim 15, characterized in that: In the step S20, the nanoparticle sol prepared in the step S10, the waterborne polyurethane resin prepolymer prepared in the step S11 and the auxiliary component prepared in the step S12 are mixed according to a proportion to prepare the coating.

17. A household appliance, characterized in that: The household appliance uses the coating according to any one of claims 1 to 13.

18. The household appliance according to claim 17, characterized in that: The household appliance comprises an air conditioner, and the coating forms a hydrophobic and oleophobic coating on the panel surface of the air conditioner through a thermal cross-linking and curing process.

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