Polyurethane coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of coatings, in particular to a polyurethane coating as well as a preparation method and application thereof. According to the invention, modified organic-inorganic composite cross-linking agents which are obtained through chemical modification and have different modification group substitution rates are grafted to polyurethane molecules, and the organic-inorganic composite cross-linking agents are prepared into the coating according to the formula, so that the haze of a formed polyurethane protective coating is not increased; and on the contrary, the haze after the coating is worn is reduced, the wear resistance of the polyurethane protective coating is improved, the polyurethane protective coating with high transparency and excellent wear resistance is realized, and the situation that the organic glass cannot resist the impact of particles such as sand wind, ice crystals or raindrops in the flying process due to poor wear resistance of the organic glass can be effectively prevented, so that the service life of the organic glass is prolonged, and the service life of the organic glass is prolonged. The surface of the organic glass is damaged, so that the visual field of a pilot is influenced, and even the life safety of the pilot is threatened.

Description

Technical Field

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

[0002] The polyurethane protective coating used on aircraft operates in harsh environments. To ensure flight safety, it must possess high light transmittance, high wear resistance, and high adhesion. Currently, the most common protective coatings applied to plexiglass are mainly silica-based. Although this type of coating has good wear resistance, it is relatively thin (usually less than 5 microns) and is prone to cracking or falling off directly after being subjected to harsh environments, making it difficult to meet actual usage requirements.

[0003] Polyhedral oligomeric silsesquioxane (POSS) is a nanoscale organic-inorganic composite material. In the mid-1990s, the U.S. Air Force Research Laboratory developed a series of POSS nanostructured hybrid systems to develop low-density, high-strength materials. POSS has irregular shapes, incomplete closed structures such as missing corners, and trapezoids, as well as completely closed cage structures such as regular hexahedrons, triangular prisms, pentagonal prisms, and hexagonal prisms. Its general chemical formula is (SiO3 / 2). n , among which the most studied is the regular hexahedral cage silsesquioxane. The structure of the POSS molecule, the eight R groups connected to the eight vertices can be fully modified or singly modified. The modified groups can still be reactive groups that are incorporated into the polymer molecular segments through chemical reactions; or they can be inert groups without reactive activity that dissolve in the polymer. POSS molecules modified with active groups can serve as crosslinking points. The structure formed by chemical bonding and size effects can hinder the segmental movement of polymer molecules and improve the material properties. Studies have confirmed that POSS molecules can form nano-scale crystals in polyurethane systems, enhancing the microphase separation between soft and hard segments; POSS modified with active groups increases chemical crosslinking in the polymer, improves the storage modulus and glass transition temperature of the material, and enhances the heat resistance and other properties of polyurethane.

[0004] However, existing protective coatings rarely combine high light transmittance, high wear resistance, and strong adhesion. Therefore, to meet the increasingly stringent engineering application requirements, it is urgent to develop a transparent, wear-resistant polyurethane protective coating for organic glass. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a polyurethane coating and a preparation method and application thereof. The coating obtained by the polyurethane coating provided by the present invention has high transparency and wear resistance.

[0006] The present invention provides a polyurethane coating, which is prepared from component A and component B in a mass fraction ratio of (0.95-1.05):1;

[0007] The component A comprises: 10-20 parts by weight of a polyol, 1-5 parts by weight of an organic-inorganic composite crosslinking agent, 0.05-0.2 parts by weight of a leveling agent, 0.05-0.2 parts by weight of a wetting agent, 0.5-2 parts by weight of a light stabilizer, 0.5-2 parts by weight of an antioxidant, 0.1-0.15 parts by weight of a slip agent, 0.03-0.05 parts by weight of a catalyst, and 45-70 parts by weight of a solvent;

[0008] The B component comprises: 3 to 15 parts by weight of diisocyanate, 3 to 15 parts by weight of polyisocyanate and 8 to 20 parts by weight of solvent;

[0009] In the component A of the present invention, the organic-inorganic composite crosslinking agent has a structure of Formula 1;

[0010] Formula 1;

[0011] Wherein, the R is a group having a structure represented by formula R-1;

[0012] Formula R-1;

[0013] And the R is substituted with a group of the structure represented by formula R-2 at a substitution rate of 15% to 20%;

[0014] Formula R-2.

[0015] The present invention in the above formula Indicates the substitution sites of Si and R groups in the structure of Formula 1.

[0016] The organic-inorganic composite crosslinking agent having the structure of formula 1 described in the present invention is an organic-inorganic composite crosslinking agent with different substitution rates of groups of the structure represented by formula R-2, wherein the R is substituted with a group of the structure represented by formula R-2 at a substitution rate of 15% to 20%. Specifically, based on the total amount of R being 100%, the proportion of the group of R represented by the structure represented by formula R-2 is 15% to 20%, and the proportion of the group of R represented by the structure represented by formula R-1 is 80% to 85%.

[0017] The inventors of the present application creatively discovered that by grafting an organic-inorganic composite crosslinking agent with different group substitution rates of the structure represented by formula R-2 obtained after chemical modification onto a polyurethane molecule, the wear resistance of the polyurethane protective coating is effectively improved while maintaining high transmittance. Specifically, the organic-inorganic composite crosslinking agent is formulated into a coating according to the formulation of the present invention. In addition to having good wear resistance, the polyurethane coating formed by the coating also has other properties such as adhesion level, transmittance and haze that are at a relatively high level within the test standards, making it a polyurethane coating with relatively strong comprehensive performance.

[0018] The polyurethane coating provided by the present invention is prepared from component A and component B in a mass fraction ratio of (0.95~1.05):1, preferably prepared from component A and component B in a mass fraction ratio of 1:1. In the component A of the present invention, the polyol is selected from one or more of polycaprolactone diol, polycaprolactone triol, polycarbonate diol, and polyether diol. The molecular weight of the polyol is 500 g / mol~2000 g / mol. Preferably, the polyol is selected from at least two polyols with different molecular weights. In certain embodiments of the present invention, the polyol is selected from polycaprolactone diol with a molecular weight of 500 g / mol~1000 g / mol and polycaprolactone triol with a molecular weight of 500 g / mol~1000 g / mol.

[0019] In component A of the present invention, the leveling agent is selected from one or more of a short-chain fluorocarbon-modified polymer leveling agent, a short-chain fluorocarbon-modified polyacrylate leveling agent, and a modified silane leveling agent; the wetting agent is selected from one or more of a polyether-modified siloxane wetting agent, a silicone wetting agent, an anionic wetting agent, and a nonionic wetting agent; the light stabilizer is selected from one or more of a 770 light stabilizer, a 944 light stabilizer, and a 292 light stabilizer; the antioxidant is selected from one or more of a 168 antioxidant, a 1010 antioxidant, a 1076 antioxidant, and a 1098 antioxidant; the lubricant is selected from one or more of a silicone lubricant, an amide lubricant, and an alkane lubricant; and the catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, and polyethyleneimine.

[0020] In the component B of the present invention, the diisocyanate is selected from one or more of 4,4'-dicyclohexylmethane diisocyanate or isophorone diisocyanate; the polyisocyanate is selected from one or more of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and toluene diisocyanate trimer.

[0021] In some embodiments of the present invention, the polyurethane coating provided by the present invention is prepared from component A and component B in a mass fraction ratio of (0.95~1.05):1, wherein component A comprises: 10~12.8 parts by weight of polycaprolactone diol, 4~7.4 parts by weight of polycaprolactone triol, 2~4 parts by weight of an organic-inorganic composite crosslinking agent, 0.05~0.15 parts by weight of a short-chain fluorocarbon modified polymer leveling agent, 0.05~0.1 parts by weight of a polyether modified siloxane wetting agent, 0.5~1 parts by weight of a 770 light stabilizer, 0.5~1 parts by weight of a 168 antioxidant, 0.1~0.15 parts by weight of an organosilicon slip agent, 0.03~0.04 parts by weight of dibutyltin dilaurate, and 50~60 parts by weight of a solvent; and component B comprises: 3~10 parts by weight of a diisocyanate, 3~8 parts by weight of a hexamethylene diisocyanate trimer, and 8~15 parts by weight of a solvent.

[0022] The present invention also provides a method for preparing the polyurethane coating according to any of the above technical solutions, comprising the following steps:

[0023] Stirring the component A and the component B under controlled temperature to obtain a polyurethane coating;

[0024] The temperature of the temperature-controlled stirring is 19°C to 23°C;

[0025] The temperature-controlled stirring time is 1.5 h to 2.5 h.

[0026] Specifically, the present invention involves temperature-controlled stirring of component A and component B, followed by quiescent stirring, to produce a polyurethane coating. More specifically, the present invention involves first preparing component A and component B, wherein component A is obtained by uniformly mixing and stirring the raw materials of component A, and component B is obtained by uniformly mixing and stirring the raw materials of component B. Component A and component B are then temperature-controlled stirring and then allowed to stand, to produce the polyurethane coating. The quiescent stirring temperature is preferably between 19°C and 23°C, and the quiescent stirring time is between 1.5 and 2.5 hours.

[0027] The present invention also provides a polyurethane coating, which is obtained by coating the polyurethane coating described in any of the above technical solutions and then curing it. The curing temperature of the present invention is 60°C to 80°C, and the curing time is 10 hours to 15 hours. Preferably, the curing temperature of the present invention is 65°C to 75°C, and the curing time is 11 hours to 13 hours.

[0028] The present invention also provides a product containing a polyurethane coating, comprising a substrate and a polyurethane coating disposed on the substrate. The polyurethane coating is obtained by coating the polyurethane coating described in any of the above technical solutions and then curing it. The curing process described in the present invention is the same as described above and will not be further described. The substrate described in the present invention is selected from organic glass, a PC substrate, or a metal substrate. The products containing the polyurethane coating described in the present invention include, but are not limited to, aircraft canopies, windshields, aircraft window glass, automobile window glass, and automobile bodies.

[0029] The present invention provides a polyurethane coating, a preparation method thereof, and an application thereof. The present invention grafts a modified organic-inorganic composite crosslinking agent with different substitution rates of modified groups obtained after chemical modification onto a polyurethane molecule, and formulates the organic-inorganic composite crosslinking agent into a coating according to the formula of the present invention. This not only does not lead to an increase in the haze of the formed polyurethane protective coating itself, but on the contrary reduces the haze after the coating is worn, improves the wear resistance of the polyurethane protective coating, and realizes a polyurethane protective coating with both high transparency and excellent wear resistance. The coating of the present invention can be applied to the surface of organic glass to effectively improve its wear resistance, and can still maintain a high light transmittance after being worn by sand and gravel, etc., and can effectively prevent the organic glass from being unable to resist the impact of particles such as wind, sand, ice crystals or raindrops during flight due to its own poor wear resistance, causing damage to the surface of the organic glass, thereby affecting the pilot's field of vision and even threatening his life safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of the organic-inorganic composite crosslinking agent of the present invention;

[0031] Figure 2 Graph showing the wear resistance of the polyurethane coatings of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0032] The present invention discloses a polyurethane coating, a preparation method thereof, and an application thereof. Those skilled in the art may refer to the contents of this invention and appropriately improve the process parameters to achieve the desired effect. It should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications herein without departing from the content, spirit, and scope of the present invention to implement and apply the technology of the present invention.

[0033] The polyhedral oligomeric silsesquioxane crosslinker (organic-inorganic composite crosslinker with different R group substitution rates) of the present invention is obtained by chemically modifying a polyhedral oligomeric silsesquioxane (POSS) having a structure of formula 1 with eight identical functional groups having a structure represented by formula R by adding functional groups having a structure represented by formula R-1 in different proportions.

[0034] The organic-inorganic composite crosslinking agents with a substitution rate of 18% used in Examples 1 to 3 of the present invention were prepared by the following steps:

[0035] Weigh 1.388 g of polyhedral oligomeric silsesquioxane (POSS), 32.29 g of di-n-butanol, and 50 g of tetrahydrofuran, heat under reflux at 60°C for 3 h, cool to room temperature, and remove tetrahydrofuran by vacuum distillation to obtain a viscous light yellow liquid, which is an organic-inorganic composite crosslinker with a substitution rate of 18%.

[0036] Formula 1; wherein, R is .

[0037] Formula R-1.

[0038] The calculation method of the substitution rate is as follows:

[0039] like Figure 1 As shown, Figure 1 It is the hydrogen nuclear magnetic resonance spectrum of the organic-inorganic composite crosslinking agent of the present invention. From the hydrogen nuclear magnetic resonance spectrum of the organic-inorganic composite crosslinking agent, it can be clearly seen that since the electronegativity of the silicon atom is less than that of the carbon atom, the signals of the methylene hydrogen atoms j1 and j2 connected to the silicon atom appear in the highest field position of the spectrum, and the positions i1, i2, h1, and h2 away from the reactive group have basically not changed; the hydrogen atoms a, b, c, and d of the di-n-butylamine part that participated in the substitution reaction all appear separately in the spectrum; the hydrogen atom e formed by epoxy ring opening overlaps with other signal peaks, and the hydrogen atom f appears in the lowest field of the spectrum and the integral area corresponds to a, b, c, and d. The signal peak of the hydrogen atom k unique to the unreacted glycidyl ether propyl group corresponds to the proportion of the group that did not participate in the reaction with the signal area of l2. By analyzing the nuclear magnetic spectrum and comparing the area of the hydrogen atom a of the di-n-butylamine part with the area of the methylene hydrogen atoms j1 and j2 connected to the silicon atom, the substitution rate is calculated = (S a / 6) / [(Sj1+Sj2) / 2].

[0040] The present invention will be further described below with reference to the embodiments:

[0041] Example 1

[0042] An organic-inorganic composite wear-resistant transparent polyurethane coating is composed of coating components A and B. The specific preparation method is as follows, and the parts involved are all parts by weight:

[0043] S1: Weigh 12.6 parts of polycaprolactone diol (molecular weight 1000 g / mol), 7.4 parts of polycaprolactone triol (molecular weight 500 g / mol), 4 parts of an organic-inorganic composite crosslinker with a substitution rate of 18%, 0.10 parts of a short-chain fluorocarbon-modified polymer leveling agent, 0.05 parts of a polyether-modified siloxane wetting agent, 0.5 parts of a 770 light stabilizer, 0.6 parts of a 168 antioxidant, 0.12 parts of an organosilicon slip agent, 0.035 parts of dibutyltin dilaurate, 26 parts of butyl acetate, 14.8 parts of propylene glycol methyl ether propionate, and 14 parts of cyclohexanone, mix and stir evenly to obtain component A of the coating.

[0044] S2: Weigh 7 parts of 4,4'-dicyclohexylmethane diisocyanate, 4.7 parts of hexamethylene diisocyanate trimer, 4.5 parts of butyl acetate, and 3.6 parts of propylene glycol methyl ether propionate, mix and stir evenly to obtain coating component B.

[0045] The above-mentioned component A and the component B are mixed in a mass fraction of 1:1, stirred at a controlled temperature of 22°C for 2 hours, and allowed to stand for 2 hours to defoam to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating. The coating is applied to the surface of a PMMA substrate and then cured at 70°C for 12 hours to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating.

[0046] Example 2

[0047] An organic-inorganic composite wear-resistant transparent polyurethane coating is composed of coating components A and B. The specific preparation method is as follows, and the parts involved are all parts by weight:

[0048] S1: Weigh 12.8 parts of polycaprolactone diol (molecular weight 1000 g / mol), 4.4 parts of polycaprolactone triol (molecular weight 500 g / mol), 3 parts of an organic-inorganic composite crosslinker with a substitution rate of 18%, 0.10 parts of a short-chain fluorocarbon-modified polymer leveling agent, 0.08 parts of a polyether-modified siloxane wetting agent, 0.5 parts of a 770 light stabilizer, 0.6 parts of a 168 antioxidant, 0.12 parts of an organosilicon slip agent, 0.035 parts of dibutyltin dilaurate, 25 parts of butyl acetate, 29 parts of propylene glycol methyl ether propionate, and 6 parts of cyclohexanone, mix and stir evenly to obtain component A of the coating.

[0049] S2: Weigh 4.2 parts of isophorone diisocyanate, 3.9 parts of hexamethylene diisocyanate trimer, 5 parts of butyl acetate, 3.6 parts of propylene glycol methyl ether propionate, and 1.4 parts of xylene, mix and stir evenly to obtain coating component B.

[0050] The above-mentioned component A and the component B are mixed in a mass fraction of 1:1, stirred at a controlled temperature of 22°C for 2 hours, and allowed to stand for 2 hours to defoam to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating. The coating is applied to the surface of a PMMA substrate and then cured at 70°C for 12 hours to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating.

[0051] Example 3

[0052] An organic-inorganic composite wear-resistant transparent polyurethane coating is composed of coating components A and B. The specific preparation method is as follows, and the parts involved are all parts by weight:

[0053] S1: Weigh 11.4 parts of polycaprolactone diol (molecular weight 500 g / mol), 6.5 parts of polycaprolactone triol (molecular weight 900 g / mol), 2 parts of an organic-inorganic composite crosslinker with a substitution rate of 18%, 0.10 parts of a short-chain fluorocarbon-modified polymer leveling agent, 0.08 parts of a polyether-modified siloxane wetting agent, 0.5 parts of a 770 light stabilizer, 0.6 parts of a 168 antioxidant, 0.12 parts of an organosilicon slip agent, 0.03 parts of dibutyltin dilaurate, 28 parts of butyl acetate, 6.2 parts of propylene glycol methyl ether propionate, and 18.2 parts of cyclohexanone, mix and stir evenly to obtain component A of the coating.

[0054] S2: Weigh 4.87 parts of 4,4'-dicyclohexylmethane diisocyanate, 4.2 parts of isophorone diisocyanate, 6.7 parts of hexamethylene diisocyanate trimer, 3.5 parts of butyl acetate, 5.6 parts of propylene glycol methyl ether propionate, and 1.4 parts of xylene, mix and stir evenly to obtain coating component B.

[0055] The above-mentioned component A and the component B are mixed in a mass fraction of 1:1, stirred at a controlled temperature of 22°C for 2 hours, and allowed to stand for 2 hours to defoam to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating. The coating is applied to the surface of a PMMA substrate and then cured at 70°C for 12 hours to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating.

[0056] Comparative Example 1

[0057] This comparative example provides a wear-resistant transparent polyurethane coating and its preparation method. The difference between this comparative example and Example 1 is that Example 1 uses an organic-inorganic composite crosslinker with an 18% substitution rate to prepare the coating, while this comparative example uses a chain extender 1,4-butanediol. The specific preparation method is as follows, and the parts involved are all parts by weight:

[0058] S1: Weigh 12.6 parts of polycaprolactone diol (molecular weight 1000 g / mol), 7.4 parts of polycaprolactone triol (molecular weight 500 g / mol), 1.1 parts of 1,4-butanediol, 0.10 parts of short-chain fluorocarbon modified polymer leveling agent, 0.05 parts of polyether modified siloxane wetting agent, 0.5 parts of 770 light stabilizer, 0.6 parts of 168 antioxidant, 0.12 parts of silicone slip agent, 0.035 parts of dibutyltin dilaurate, 19.6 parts of butyl acetate, 18.7 parts of propylene glycol methyl ether propionate, and 10 parts of cyclohexanone, mix and stir evenly to obtain coating component A.

[0059] S2: Weigh 7.93 parts of 4,4'-dicyclohexylmethane diisocyanate, 11.8 parts of hexamethylene diisocyanate trimer, 4.5 parts of butyl acetate, 3.6 parts of propylene glycol methyl ether propionate, and 1.4 parts of xylene, mix and stir evenly to obtain coating component B.

[0060] The above-mentioned component A and the component B are mixed in a mass fraction of 1:1, stirred at a controlled temperature of 22°C for 2 hours, and allowed to stand for 2 hours to defoam to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating. The coating is applied to the surface of a PMMA substrate and then cured at 70°C for 12 hours to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating.

[0061] Comparative Example 2

[0062] This comparative example provides a wear-resistant transparent polyurethane coating and its preparation method. The difference between this comparative example and Example 1 is that Example 1 uses an organic-inorganic composite crosslinker with a substitution rate of 18% to prepare the coating, while this comparative example uses an organic-inorganic composite crosslinker with a substitution rate of 6%. The specific preparation method is as follows, and the parts involved are all parts by weight:

[0063] S1: Weigh 12.6 parts of polycaprolactone diol (molecular weight 1000 g / mol), 7.4 parts of polycaprolactone triol (molecular weight 500 g / mol), 4 parts of an organic-inorganic composite crosslinker with a substitution rate of 6%, 0.10 parts of a short-chain fluorocarbon-modified polymer leveling agent, 0.05 parts of a polyether-modified siloxane wetting agent, 0.5 parts of a 770 light stabilizer, 0.6 parts of a 168 antioxidant, 0.12 parts of an organosilicon slip agent, 0.035 parts of dibutyltin dilaurate, 26 parts of butyl acetate, 14.8 parts of propylene glycol methyl ether propionate, and 14 parts of cyclohexanone, mix and stir evenly to obtain component A of the coating.

[0064] S2: Weigh 7 parts of 4,4'-dicyclohexylmethane diisocyanate, 4.7 parts of hexamethylene diisocyanate trimer, 4.5 parts of butyl acetate, and 3.6 parts of propylene glycol methyl ether propionate, mix and stir evenly to obtain coating component B.

[0065] The above-mentioned component A and the component B are mixed in a mass fraction of 1:1, stirred at a controlled temperature of 22°C for 2 hours, and allowed to stand for 2 hours to defoam to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating. The coating is applied to the surface of a PMMA substrate and then cured at 70°C for 12 hours to obtain an organic-inorganic composite wear-resistant transparent polyurethane coating.

[0066] Performance testing:

[0067] The organic-inorganic composite wear-resistant transparent polyurethane coatings obtained in Examples 1-3 and Comparative Examples 1-2 were subjected to the following tests:

[0068] Coating adhesion test: The coating adhesion was tested according to ASTM D3359-02.

[0069] Light transmittance and haze test: in accordance with GB / T 2410-2008 “Transparent plastics - Determination of light transmittance and haze”.

[0070] Wear resistance:

[0071] Method 1: Testing was conducted in accordance with ASTM F735-11 using a reciprocating sand abrasion tester (Taber 6160) at a cycle rate of 150 cycles / minute and 100 strokes. The degree of wear was measured by the change in the coating's transmittance and haze before and after the test, expressed as Δ transmittance / Δ haze in Table 1 below.

[0072] Method 2: According to ASTM-D3884, the coating was abraded 1000 times with a 500g CS-10 grinding wheel using a rotating platform double-head abrader. The degree of wear was measured by the change in coating haze before and after the test, represented by Δhaze in Table 1 below.

[0073] The test results are shown in Table 1:

[0074] Table 1

[0075]

[0076] The test results in Table 1 show that the organic-inorganic composite wear-resistant transparent polyurethane coatings prepared in Examples 1 to 3 all have an adhesion grade of 5B, a transmittance greater than 91%, and a haze less than 0.5. After a Taber 100 stroke friction test, the increase in transmittance of the coatings was basically within 1.0%, and the increase in haze was less than 0.2, indicating good wear resistance.

[0077] Compared with Example 1, the wear-resistant polyurethane coating prepared in Comparative Example 1 does not contain an organic-inorganic composite crosslinking agent. The coatings prepared by the two methods have obvious differences after the wear resistance test of Method 2, such as Figure 2 As shown, Figure 2The wear resistance diagram of the polyurethane coating of Example 1 and Comparative Example 1 is shown. Figure 2 The left side a shows the wear resistance of the polyurethane coating of Example 1. Figure 2 The b on the right side of the figure shows the wear resistance of the polyurethane coating of Comparative Example 1. Figure 2 It can be seen that the haze of the wear-resistant transparent polyurethane coating prepared in Comparative Example 1 is greatly increased after being polished with a grinding wheel, scratches are obvious, and the wear resistance of the coating is poor.

[0078] Compared with Example 1, although the wear-resistant polyurethane coating prepared in Comparative Example 2 contains an organic-inorganic composite crosslinker, the substitution rate of the organic-inorganic composite crosslinker added therein is low, resulting in a significant increase in the haze of the coating after the wear resistance test, and the wear resistance of the coating is poor.

[0079] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A polyurethane coating, characterized in that: It is prepared from component A and component B with a mass fraction ratio of (0.95~1.05):1; The component A comprises: 10-20 parts by weight of a polyol, 1-5 parts by weight of an organic-inorganic composite crosslinking agent, 0.05-0.2 parts by weight of a leveling agent, 0.05-0.2 parts by weight of a wetting agent, 0.5-2 parts by weight of a light stabilizer, 0.5-2 parts by weight of an antioxidant, 0.1-0.15 parts by weight of a slip agent, 0.03-0.05 parts by weight of a catalyst, and 45-70 parts by weight of a solvent; The organic-inorganic composite crosslinking agent has a structure of formula 1; Formula 1; Wherein, the R is a group having a structure represented by formula R-1; Formula R-1; And the R is substituted with a group of the structure represented by formula R-2 at a substitution rate of 15% to 20%; Formula R-2; The B component comprises: 3 to 15 parts by weight of diisocyanate, 3 to 15 parts by weight of polyisocyanate and 8 to 20 parts by weight of solvent.

2. The polyurethane coating according to claim 1, characterized in that In the component A, the polyol is selected from one or more of polycaprolactone diol, polycaprolactone triol, polycarbonate diol, and polyether diol.

3. The polyurethane coating according to claim 1, characterized in that The molecular weight of the polyol is 500 g / mol to 2000 g / mol.

4. The polyurethane coating according to claim 3, characterized in that In the component A, the polyol is selected from at least two polyols with different molecular weights.

5. The polyurethane coating according to claim 4, characterized in that In the component A, the polyol is selected from polycaprolactone diol with a molecular weight of 500 g / mol to 1000 g / mol and polycaprolactone triol with a molecular weight of 500 g / mol to 1000 g / mol.

6. The polyurethane coating according to claim 1, characterized in that In the component A, the leveling agent is selected from one or more of a short-chain fluorocarbon modified polymer leveling agent, a short-chain fluorocarbon modified polyacrylate leveling agent, and a modified silane leveling agent; The wetting agent is selected from one or more of polyether modified siloxane wetting agents, silicone wetting agents, anionic wetting agents, and nonionic wetting agents; The light stabilizer is selected from one or more of 770 light stabilizer, 944 light stabilizer, and 292 light stabilizer; The antioxidant is selected from one or more of 168 antioxidants, 1010 antioxidants, 1076 antioxidants, and 1098 antioxidants; The lubricant is selected from one or more of silicone lubricants, amide lubricants, and alkane lubricants; The catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, and polyethyleneimine; In the B component, the diisocyanate is selected from one or more of 4,4'-dicyclohexylmethane diisocyanate and isophorone diisocyanate; The polyisocyanate is selected from one or more of hexamethylene diisocyanate trimer, isophorone diisocyanate trimer, and toluene diisocyanate trimer.

7. The polyurethane coating according to any one of claims 1 to 6, characterized in that: The component A comprises: 10-12.8 parts by weight of polycaprolactone diol, 4-7.4 parts by weight of polycaprolactone triol, 2-4 parts by weight of an organic-inorganic composite crosslinking agent, 0.05-0.15 parts by weight of a short-chain fluorocarbon modified polymer leveling agent, 0.05-0.1 parts by weight of a polyether modified siloxane wetting agent, 0.5-1 parts by weight of a 770 light stabilizer, 0.5-1 parts by weight of a 168 antioxidant, 0.1-0.15 parts by weight of an organosilicon slip agent, 0.03-0.04 parts by weight of dibutyltin dilaurate, and 50-60 parts by weight of a solvent; The component B comprises: 3 to 10 parts by weight of diisocyanate, 3 to 8 parts by weight of hexamethylene diisocyanate trimer and 8 to 15 parts by weight of solvent.

8. The method for preparing the polyurethane coating according to any one of claims 1 to 7, characterized in that: The following steps are involved: Stirring the component A and the component B under controlled temperature to obtain a polyurethane coating; The temperature of the temperature-controlled stirring is 19°C to 23°C; The temperature-controlled stirring time is 1.5 h to 2.5 h.

9. A polyurethane coating, characterized in that The polyurethane coating according to any one of claims 1 to 7 is obtained by coating to form a film and then curing it.

10. A product containing a polyurethane coating, characterized in that: The invention comprises a substrate and a polyurethane coating arranged on the substrate, wherein the polyurethane coating is obtained by coating the polyurethane coating according to any one of claims 1 to 7 and then curing the coating.

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