A kind of anti-dust polyurethane coating, preparation method and application thereof

Abstract

The present invention provides an anti-dust polyurethane coating, which is prepared from component A and component B, wherein the mass ratio of component A to component B is 1:1; component A is prepared from polyol, chain extender, leveling agent, wetting agent, light stabilizer, antioxidant, ultraviolet absorber, slip agent and catalyst; component B is prepared from polyurethane prepolymer, aliphatic diisocyanate and aliphatic triisocyanate. The present application also provides a preparation method of the anti-dust polyurethane coating, a polyurethane coating and its application. The polyurethane coating provided by the present application is prepared by a two-step method, and by introducing a slip agent, the obtained polyurethane coating has good wear resistance, high light transmittance, strong adhesion and anti-dust performance.

Description

Technical Field

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

[0002] Polymethyl methacrylate, a transparent polymer material commonly known as plexiglass, is an important thermoplastic that was developed earlier. Due to its high stability, low price and easy processing, plexiglass has been widely used. After the 1950s, this type of material was used in cockpit covers, windshields and other parts of civil and military aircraft. In response to the needs of military aircraft, the cockpit cover has a low emissivity in the 8-14μm atmospheric window, which can reduce the probability of the aircraft being tracked by missiles and significantly improve the aircraft's survivability.

[0003] Generally speaking, the emissivity of the canopy can be reduced by sputtering a semiconductor film on the surface. However, due to the poor wear resistance of the canopy substrate, the semiconductor film layer and the canopy are easily worn in complex flight environments, such as deserts, Gobi and other sandy areas, which is not conducive to flight safety. Under current technical conditions, in order to ensure excellent low emissivity and wear resistance, it is often necessary to reduce the hard segment content of the polyurethane coating, which will result in low hardness, low smoothness, and poor anti-dust effect. During the application process, excessive dust adsorption will lead to a decrease in transmittance and an increase in haze, which will seriously affect the optical properties of the coating and threaten flight safety. Therefore, in order to solve the problem of poor anti-dust performance, it is of great significance to develop a transparent protective coating with simple process, anti-dust and strong wear resistance, and no effect on the function of the semiconductor film layer to achieve the protection of the semiconductor film on the surface of the canopy.

[0004] The Chinese patent with publication number CN110229610A discloses a method for preparing an anti-ash liquid and an anti-ash coating, wherein the anti-ash liquid and the anti-ash coating include the following raw materials by weight: 20 parts of triethylethoxysilane, 5 parts of butyl titanate, 6 parts of ethyl orthosilicate, 3 parts of organic bismuth catalyst, 5 parts of glacial acetic acid and 61 parts of isopropanol. The technical scheme tested the anti-ash performance of the coating, and the obtained coating had excellent anti-ash performance, with the amount of ash per unit area less than 0.01 mg / cm 2 .

[0005] The Chinese patent with publication number CN109161290A discloses a method for preparing an organic glass anti-fouling coating, wherein the organic glass anti-fouling coating is composed of the following components in weight percentage: 2% to 10% of methacrylate copolymer, 2% to 8% of modified silicon dioxide, 1% to 5% of polypeptide amino acid surfactant, and the balance is ethyl acetate. The organic glass anti-fouling coating prepared by this technical solution can make the organic glass maintain the light transmittance of the original material and effectively improve the wear resistance. At the same time, the hydrophilicity and oleophobicity of the coating surface enhance the anti-fouling performance of the coating. However, the anti-fouling performance is not equivalent to the anti-dust performance, and the adhesion performance of the coating is not reflected.

[0006] The Chinese patent with publication number CN115820106A discloses a method for preparing an anti-fouling and wear-resistant coating stock solution, wherein the anti-fouling and wear-resistant coating and coating stock solution are composed of the following components in weight percentage: 50% polyurethane modified acrylate, 45% butyl acetate, 3% photoinitiator, 1.5% slip agent, and 0.5% leveling agent. The anti-fouling and wear-resistant coating prepared by this technical solution has high light transmittance and good wear resistance, and improves the surface hardness of organic glass; however, the anti-fouling performance is not equivalent to the anti-dust performance.

[0007] In summary, the protective coatings prepared by the existing technology can hardly have important properties such as high light transmittance, high wear resistance, high adhesion and strong anti-dust ability. There is currently no industry standard for the anti-dust performance of thin film coatings for researchers to refer to, and most anti-fouling coating patents do not systematically test the important performance of anti-dust coatings. Therefore, it is of great significance to develop a transparent polyurethane coating that is anti-dust and has strong comprehensive performance and can be applied to the surface of organic glass. Summary of the invention

[0008] The technical problem solved by the present invention is to provide a polyurethane coating with high light transmittance, high wear resistance, high adhesion, strong anti-fouling ability and not easy to be stained with dust.

[0009] In view of this, the present application provides an anti-dust polyurethane coating, which is prepared from component A and component B, wherein the mass ratio of component A to component B is 1:1;

[0010] The component A is prepared from the following raw materials: 4 to 12 parts by weight of polyol, 0.1 to 1.5 parts by weight of chain extender, 0.1 to 0.2 parts by weight of leveling agent, 0.05 to 0.2 parts by weight of wetting agent, 0.1 to 0.5 parts by weight of light stabilizer, 0.1 to 0.5 parts by weight of antioxidant, 0.1 to 0.5 parts by weight of ultraviolet absorber, 0.1 to 0.15 parts by weight of lubricant, and 0.01 to 0.3 parts by weight of catalyst;

[0011] The component B is prepared from the following raw materials: 25 to 35 parts by weight of polyurethane prepolymer, 0.5 to 2 parts by weight of aliphatic diisocyanate, and 0 to 7 parts by weight of aliphatic triisocyanate.

[0012] Preferably, in the component A, the polyol is a combination of polyolefin polyols of different molecular weights, and the molecular weight range is 1000-3000 g / mol; the chain extender is selected from one or two of N,N"-di-tert-butylethylenediamine and triethanolamine; the leveling agent is 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 one or more of a polyether-modified siloxane wetting agent; the light stabilizer is a 770 light stabilizer; the antioxidant is a 1010 antioxidant; the ultraviolet absorber is a 531 ultraviolet absorber; the lubricant is a silicone lubricant; and the catalyst is dibutyltin dilaurate;

[0013] In the component B, the aliphatic diisocyanate is selected from one or two of 4,4'-dicyclohexylmethane diisocyanate and hexamethylene diisocyanate trimer; the aliphatic triisocyanate is isophorone diisocyanate trimer;

[0014] The preparation method of the polyurethane prepolymer is specifically as follows:

[0015] The polybutadiene polyol is dehydrated and dissolved in a solvent, and then isocyanate and a catalyst are added to react to obtain a polyurethane prepolymer.

[0016] Preferably, the content of the lubricant is 0.12 to 0.14 parts by weight.

[0017] The present application also provides a method for preparing the anti-dust polyurethane coating, comprising the following steps:

[0018] Mix 4-12 parts by weight of a polyol, 0.1-1.5 parts by weight of a chain extender, 0.1-0.2 parts by weight of a leveling agent, 0.05-0.2 parts by weight of a wetting agent, 0.1-0.5 parts by weight of a light stabilizer, 0.1-0.5 parts by weight of an antioxidant, 0.1-0.5 parts by weight of an ultraviolet absorber, 0.1-0.15 parts by weight of a lubricant, and 0.01-0.3 parts by weight of a catalyst in a solvent to obtain component A;

[0019] Mixing 25 to 35 parts by weight of a polyurethane prepolymer, 0.5 to 2 parts by weight of an aliphatic diisocyanate, and 0 to 7 parts by weight of an aliphatic triisocyanate in a solvent to obtain component B;

[0020] Component A and component B are mixed in a mass ratio of 1:1, reacted, and allowed to stand to obtain an anti-dust polyurethane coating.

[0021] Preferably, the preparation method of the polyurethane prepolymer is specifically as follows:

[0022] The polybutadiene polyol is dehydrated and dissolved in a solvent, and then isocyanate and a catalyst are added to react to obtain a polyurethane prepolymer.

[0023] Preferably, in the preparation process of the polyurethane prepolymer, the isocyanate is selected from isophorone diisocyanate trimer, the catalyst is selected from dibutyltin dilaurate; and the molar ratio of the OH group in the polybutadiene polyol to the NCO group in the isophorone diisocyanate trimer is 1:3; the reaction temperature is 60-70°C, and the reaction time is 4-5h.

[0024] Preferably, in the step of obtaining the anti-dust polyurethane coating, the reaction temperature is 18 to 30° C., the reaction time is 2 to 4 hours, and the standing time is 2 to 4 hours.

[0025] The present application also provides a polyurethane coating, wherein the polyurethane coating is an anti-dust polyurethane coating obtained by coating and film-forming and curing; the anti-dust polyurethane coating is the anti-dust polyurethane coating or the anti-dust polyurethane coating prepared by the preparation method.

[0026] The present application also provides an organic composite material, comprising a modified substrate and a polyurethane coating compounded on the surface of the modified substrate; the polyurethane coating is the polyurethane coating, and the modified substrate is a substrate modified by a silane coupling agent.

[0027] Preferably, the substrate is a semiconductor film / PMMA substrate.

[0028] The present application provides an anti-dust polyurethane coating, which is prepared from component A and component B, wherein the polyurethane prepolymer in component B is prepared in advance and then introduced, which can make the reaction exotherm low and the reaction process smooth during the preparation of the polyurethane coating, promote the hydrogen bonding between the polyurethane chain segments, effectively improve the hardness and anti-dust performance of the coating, and the prepared polyurethane coating has good wear resistance, high light transmittance and strong adhesion; at the same time, the introduction of the lubricant in component A is combined with the method of preparing the polyurethane prepolymer first, which is more conducive to improving the anti-dust property of the polyurethane coating; further, the introduction of the ternary component in the anti-dust polyurethane coating provided by the present application constructs a cross-linked structure between the polyurethane chain segments, inhibits the crystallization of the polyurethane chain segments, avoids the increase of haze due to refraction of the crystallization area, and at the same time improves the cross-linking density of the polyurethane, enhances the wear resistance of the polyurethane coating, and realizes the simultaneous optimization of the optical properties and wear resistance of the coating.

[0029] The present application also provides a method for preparing an anti-dust polyurethane coating, which first prepares a polyurethane prepolymer and then prepares component A and component B. This two-step method has low reaction exotherm and a smooth reaction process, promotes hydrogen bonding between polyurethane chain segments, effectively improves the hardness of the coating and the anti-dust performance, and the prepared polyurethane coating has good wear resistance, high light transmittance and strong adhesion; at the same time, the prepolymer method and the introduction of a lubricant can be more conducive to improving the anti-dust performance of the polyurethane coating.

[0030] On the other hand, the present application uses a silane coupling agent solution to modify the substrate, constructs a chemical bond between the substrate and the polyurethane chain segment, and effectively enhances the adhesion of the coating during the coating process of the anti-dust and wear-resistant coating; the coating process of the polyurethane coating is preferably carried out using a curtain coating process, which does not require other coating equipment to achieve excellent surface leveling, reduces the cost of use, and is simple to operate, thereby realizing the preparation of a transparent polyurethane protective coating that is anti-dust and wear-resistant and has strong comprehensiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figures are dust staining photos of the dust-resistant and wear-resistant coatings prepared in the examples and comparative examples, wherein (1), (2) and (3) are dust staining photos of the dust-resistant and wear-resistant coatings of example 1, comparative example 1 and comparative example 3, respectively. DETAILED DESCRIPTION

[0032] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0033] In view of the problem that polyurethane coatings in the prior art cannot have important properties such as high light transmittance, high wear resistance, high adhesion and strong anti-dust ability, the present application provides an anti-dust polyurethane coating, and the polyurethane coating prepared by the coating can achieve the performance advantages of anti-dust and wear resistance and strong comprehensiveness. Specifically, the embodiment of the present invention discloses an anti-dust polyurethane coating, which is prepared from component A and component B, and the mass ratio of component A to component B is 1:1;

[0034] The component A is prepared from the following raw materials: 4 to 12 parts by weight of polyol, 0.1 to 1.5 parts by weight of chain extender, 0.1 to 0.2 parts by weight of leveling agent, 0.05 to 0.2 parts by weight of wetting agent, 0.1 to 0.5 parts by weight of light stabilizer, 0.1 to 0.5 parts by weight of antioxidant, 0.1 to 0.5 parts by weight of ultraviolet absorber, 0.1 to 0.15 parts by weight of lubricant, and 0.01 to 0.3 parts by weight of catalyst;

[0035] The component B is prepared from the following raw materials: 25 to 35 parts by weight of polyurethane prepolymer, 0.5 to 2 parts by weight of aliphatic diisocyanate, and 0 to 7 parts by weight of aliphatic triisocyanate.

[0036] For the anti-dust polyurethane coating provided in the present application, a polyurethane prepolymer is first prepared, specifically:

[0037] The polybutadiene polyol is vacuum-dried and dissolved in an organic solvent, and then isocyanate and a catalyst are added to react to obtain an isocyanate-terminated polyurethane prepolymer.

[0038] In the preparation process of the polyurethane prepolymer, the molecular weight of the polybutadiene polyol is 3000g / mol, the isocyanate is specifically selected from isophorone diisocyanate trimer, the catalyst is selected from an organic tin catalyst, more specifically dibutyltin dilaurate, and the molar ratio of OH in the polybutadiene polyol to NCO in the isocyanate is 1:3, so as to ensure a reasonable ratio of the polyol and the isocyanate and prevent problems such as product gelation. The reaction temperature is 50-100°C and the time is 2-5h; more specifically, the reaction temperature is 70-90°C and the time is 3-4h.

[0039] Component A provided in the present application is prepared from the following raw materials: 4 to 12 parts by weight of polyol, 0.1 to 1.5 parts by weight of chain extender, 0.1 to 0.2 parts by weight of leveling agent, 0.05 to 0.2 parts by weight of wetting agent, 0.1 to 0.5 parts by weight of light stabilizer, 0.1 to 0.5 parts by weight of antioxidant, 0.1 to 0.5 parts by weight of ultraviolet absorber, 0.1 to 0.5 parts by weight of lubricant, and 0.01 to 0.3 parts by weight of catalyst. Wherein, the polyol is a combination of polyolefin polyols of different molecular weights, with a molecular weight range of 1000 to 3000 g / mol. Specifically, the content of the polyol is 6 to 11 parts by weight. The chain extender is selected from one or two of N, N"-di-tert-butylethylenediamine and triethanolamine. In a specific embodiment, the chain extender is selected from N, N"-di-tert-butylethylenediamine and triethanolamine; specifically, the content of the chain extender is 0.4 to 1.1 parts by weight. The leveling agent is 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. In a specific embodiment, the leveling agent is selected from a short-chain fluorocarbon modified polymer leveling agent; specifically, the content of the leveling agent is 0.15 to 0.18 parts by weight. The wetting agent is one or more of a polyether modified siloxane wetting agent, specifically, the content of the wetting agent is 0.06 to 0.15 parts by weight. The light stabilizer is a 770 light stabilizer, specifically, the content of the light stabilizer is 0.2 to 0.4 parts by weight. The antioxidant is a 1010 antioxidant, specifically, the content of the antioxidant is 0.2 to 0.4 parts by weight. The ultraviolet absorber is a 531 ultraviolet absorber, specifically, the content of the ultraviolet absorber is 0.2 to 0.4 parts by weight. The lubricant is an organosilicon lubricant. In a specific embodiment, the organosilicon lubricant is EL-2550. Specifically, the content of the lubricant is 0.12 to 0.14 parts by weight. The catalyst is dibutyltin dilaurate. Specifically, the content of the catalyst is 0.1 to 0.2 parts by weight.

[0040] Component B is prepared from the following raw materials: 25 to 35 parts by weight of polyurethane prepolymer, 0.5 to 2 parts by weight of aliphatic diisocyanate, and 0 to 7 parts by weight of aliphatic triisocyanate. The aliphatic diisocyanate is selected from one or two of 4,4'-dicyclohexylmethane diisocyanate and hexamethylene diisocyanate trimer. In a specific embodiment, the aliphatic diisocyanate is selected from 4,4'-dicyclohexylmethane diisocyanate and hexamethylene diisocyanate trimer; specifically, the content of the aliphatic diisocyanate is 0.7 to 1.8 parts by weight. The aliphatic triisocyanate is isophorone diisocyanate trimer, and specifically, the content of the aliphatic triisocyanate is 0 to 1 part by weight.

[0041] The present application also provides a method for preparing an anti-dust polyester coating, comprising the following steps:

[0042] Mix 4-12 parts by weight of a polyol, 0.1-1.5 parts by weight of a chain extender, 0.1-0.2 parts by weight of a leveling agent, 0.05-0.2 parts by weight of a wetting agent, 0.1-0.5 parts by weight of a light stabilizer, 0.1-0.5 parts by weight of an antioxidant, 0.1-0.5 parts by weight of an ultraviolet absorber, 0.1-0.15 parts by weight of a lubricant, and 0.01-0.3 parts by weight of a catalyst in a solvent to obtain component A;

[0043] Mixing 25 to 35 parts by weight of a polyurethane prepolymer, 0.5 to 2 parts by weight of an aliphatic diisocyanate, and 0 to 7 parts by weight of an aliphatic triisocyanate in a solvent to obtain component B;

[0044] Component A and component B are mixed in a mass ratio of 1:1, reacted, and allowed to stand to obtain an anti-dust polyurethane coating.

[0045] In the preparation method of the anti-dust polyester, a polyurethane prepolymer is first prepared, and the preparation method thereof has been described in detail above and will not be repeated here.

[0046] After preparing the polyurethane prepolymer, the present application prepares component A and component B respectively. In the step of preparing component A, the solvent is selected from one or more of cyclohexanone, propylene glycol methyl ether propionate, dioxane and toluene; in the step of preparing component B, the solvent is one or more of cyclohexanone, propylene glycol methyl ether propionate, dioxane and toluene. The solvents in component A and component B can be the same or different, and the present application does not impose any special restrictions on this.

[0047] After obtaining component A and component B, component A and component B are mixed, reacted, and allowed to stand according to a mass ratio to obtain an anti-dust polyurethane coating. The reaction temperature is 18 to 30° C., the time is 2 to 4 hours, and the standing time is 2 to 4 hours; specifically, the reaction temperature is 18 to 25° C., the time is 2 hours, and the standing time is 3 hours.

[0048] The anti-dust polyurethane coating provided in the present application first prepares a polyurethane prepolymer, and then prepares component A and component B separately, and the polyurethane prepolymer is introduced into component B; the two-step method can make the heat release during the reaction low and the process smooth, and promote the hydrogen bonding effect between the polyurethane chain segments.

[0049] The present application also provides a polyurethane coating, which is obtained by coating the polyurethane coating to form a film and then curing it.

[0050] The polyurethane coating provided by the present application is obtained by coating the polyurethane coating to form a film and curing the film. The curing temperature is 50-100° C. and the time is 5-10 hours. The hard segment content of the polyurethane coating is 20-30%.

[0051] Furthermore, the present application also provides an organic composite material, comprising a modified substrate and a polyurethane coating compounded on the surface of the modified substrate; the polyurethane coating is the polyurethane coating described in the above scheme, and the modified substrate is a substrate modified by a silane coupling agent.

[0052] In the organic composite material, the matrix can specifically be a semiconductor film / PMMA substrate; the modified matrix specifically uses a solution containing a silane coupling agent to perform surface modification on the semiconductor film / PMMA substrate, thereby constructing a chemical bond between the semiconductor film / PMMA surface and the polyurethane chain segment, and then compounding the polyurethane coating. Specifically, the polyurethane coating is compounded on the surface of the modified matrix by coating, which can effectively enhance the adhesion of the coating.

[0053] In order to further understand the present invention, the anti-dust polyurethane coating provided by the present invention, its preparation method and application are described in detail below in conjunction with embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0054] Example 1

[0055] A dust-resistant transparent polyurethane coating is composed of a coating component A and a coating component B. The specific preparation method is as follows:

[0056] S1: Add polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, and remove water under vacuum at 120° C. for 2 h; Take 31.99 parts of the above dehydrated polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, add 50.00 parts of cyclohexanone, 18.00 parts of isophorone diisocyanate trimer, and 0.0074 parts of dibutyltin dilaurate, and react at 70° C. for 4 h under nitrogen protection to obtain a polyurethane prepolymer;

[0057] S2: Weigh 5.2 parts of polybutadiene polyol (molecular weight 3000 g / mol), 4.8 parts of polybutadiene polyol (molecular weight 1000 g / mol), 0.21 parts of N,N"-di-tert-butylethylenediamine, 0.22 parts of triethanolamine, 0.16 parts of short-chain fluorocarbon modified polymer leveling agent, 0.06 parts of polyether modified siloxane wetting agent, 0.3 parts of 531 ultraviolet absorber, 0.3 parts of 770 light stabilizer, 0.2 parts of 1010 antioxidant, 0.12 parts of silicone slip agent, 0.1 parts of dibutyltin dilaurate, 25.0 parts of propylene glycol methyl ether propionate, and 13.5 parts of cyclohexanone, mix and stir to obtain coating component A;

[0058] S3: Weigh 29.7 parts of polyurethane prepolymer, 0.52 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.18 parts of hexamethylene diisocyanate trimer, 13.0 parts of propylene glycol methyl ether propionate, and 6.6 parts of cyclohexanone, mix and stir evenly to obtain coating component B;

[0059] The above component A and the above component B are mixed at a mass fraction of 1:1, stirred at 25°C for 2 hours, and allowed to stand for 3 hours to eliminate bubbles, to obtain a dust-resistant transparent polyurethane coating;

[0060] Semiconductor film / PMMA substrate surface modification method: Take 0.2g KH550 silane coupling agent and dissolve it in 6g distilled water, mix well to obtain a modified solution, and apply it on the surface of the substrate for modification;

[0061] The anti-dust transparent polyurethane coating was applied to the surface of the modified semiconductor film / PMMA substrate, and after being dried at room temperature, it was cured at 60° C. for 8 hours to obtain an anti-dust transparent polyurethane coating with a hard segment content of 20%.

[0062] Example 2

[0063] A dust-resistant transparent polyurethane coating is composed of a coating component A and a coating component B. The specific preparation method is as follows:

[0064] S1: Add polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, and remove water under vacuum at 120° C. for 2 h; Take 31.99 parts of the above dehydrated polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, add 50.00 parts of cyclohexanone, 18.00 parts of isophorone diisocyanate trimer, and 0.0074 parts of dibutyltin dilaurate, and react at 70° C. for 4 h under nitrogen protection to obtain a polyurethane prepolymer;

[0065] S2: Weigh 6.65 parts of polybutadiene polyol (molecular weight 3000 g / mol), 4.8 parts of polybutadiene polyol (molecular weight 1000 g / mol), 0.28 parts of N,N"-di-tert-butylethylenediamine, 0.18 parts of triethanolamine, 0.16 parts of short-chain fluorocarbon modified polymer leveling agent, 0.15 parts of polyether modified siloxane wetting agent, 0.3 parts of 531 ultraviolet absorber, 0.3 parts of 770 light stabilizer, 0.2 parts of 1010 antioxidant, 0.12 parts of silicone slip agent, 0.1 parts of dibutyltin dilaurate, 12.3 parts of toluene, and 24.5 parts of cyclohexanone, mix and stir to obtain coating component A;

[0066] S3: Weigh 25.0 parts of polyurethane prepolymer, 0.54 parts of 4,4'-dicyclohexylmethane diisocyanate, 1.0 parts of isophorone diisocyanate trimer, 0.18 parts of hexamethylene diisocyanate trimer, and 23.3 parts of cyclohexanone, mix and stir evenly to obtain coating component B;

[0067] The above component A and the above component B are mixed at a mass fraction of 1:1, stirred at 25°C for 2 hours, and allowed to stand for 3 hours to eliminate bubbles, to obtain a dust-resistant transparent polyurethane coating;

[0068] Semiconductor film / PMMA substrate surface modification method: Take 0.2g KH550 silane coupling agent and dissolve it in 6g distilled water, mix well to obtain a modified solution, and apply it on the surface of the substrate for modification;

[0069] The anti-dust transparent polyurethane coating was applied to the surface of the modified semiconductor film / PMMA substrate, and after being dried at room temperature, it was cured at 60° C. for 8 hours to obtain an anti-dust transparent polyurethane coating with a hard segment content of 20%.

[0070] Example 3

[0071] A dust-resistant transparent polyurethane coating is composed of a coating component A and a coating component B. The specific preparation method is as follows:

[0072] S1: Add polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, and remove water under vacuum at 120° C. for 2 h; Take 31.99 parts of the above dehydrated polybutadiene polyol (molecular weight 3000 g / mol) into a reactor, add 50.00 parts of cyclohexanone, 18.00 parts of isophorone diisocyanate trimer, and 0.0074 parts of dibutyltin dilaurate, and react at 70° C. for 4 h under nitrogen protection to obtain a polyurethane prepolymer;

[0073] S2: Weigh 5.06 parts of polybutadiene polyol (molecular weight 3000 g / mol), 4.8 parts of polybutadiene polyol (molecular weight 1000 g / mol), 0.53 parts of N,N"-di-tert-butylethylenediamine, 0.50 parts of triethanolamine, 0.16 parts of short-chain fluorocarbon modified polymer leveling agent, 0.15 parts of polyether modified siloxane wetting agent, 0.3 parts of 531 ultraviolet absorber, 0.3 parts of 770 light stabilizer, 0.2 parts of 1010 antioxidant, 0.12 parts of silicone slip agent, 0.1 parts of dibutyltin dilaurate, 16.3 parts of toluene, and 21.5 parts of cyclohexanone, mix and stir to obtain coating component A;

[0074] S3: Weigh 30.0 parts of polyurethane prepolymer, 0.9 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.7 parts of hexamethylene diisocyanate trimer, 0.746 parts of isophorone diisocyanate trimer, and 17.7 parts of cyclohexanone, mix and stir to obtain coating component B;

[0075] The above component A and the above component B are mixed at a mass fraction of 1:1, stirred at 25°C for 2 hours, and allowed to stand for 3 hours to eliminate bubbles, to obtain a dust-resistant transparent polyurethane coating;

[0076] Semiconductor film / PMMA substrate surface modification method: Take 0.2g KH550 silane coupling agent and dissolve it in 6g distilled water and mix well to obtain a modified solution, which is then applied to the substrate surface for modification;

[0077] The anti-dust transparent polyurethane coating was coated on the surface of the modified semiconductor film / PMMA substrate, and after being dried at room temperature, it was cured at 60° C. for 8 hours to obtain an anti-dust transparent polyurethane coating with a hard segment content of 30%.

[0078] Comparative Example 1

[0079] This comparative example provides a dust-resistant transparent polyurethane coating and a preparation method thereof. The difference between this comparative example and Example 1 is that Example 1 adopts a prepolymer method (two-step method) to prepare the coating, while the preparation method of this comparative example is a one-step method, and the preparation raw materials are the same as those in Example 1, specifically consisting of a coating component A and a coating component B:

[0080] Component A of the coating: 14.6 parts of polybutadiene polyol (molecular weight 3000 g / mol) after dehydration, 4.8 parts of polybutadiene polyol (molecular weight 1000 g / mol), 0.21 parts of N,N"-di-tert-butylethylenediamine, 0.22 parts of triethanolamine, 0.16 parts of short-chain fluorocarbon modified polymer leveling agent, 0.06 parts of polyether modified siloxane wetting agent, 0.3 parts of 531 ultraviolet absorber, 0.3 parts of 770 light stabilizer, 0.2 parts of 1010 antioxidant, 0.12 parts of silicone slip agent, 0.2 parts of dibutyltin dilaurate, 28.5 parts of propylene glycol methyl ether propionate, and 9.5 parts of cyclohexanone, mixed and stirred to obtain component A of the coating;

[0081] Coating component B: 5.4 parts of isophorone diisocyanate trimer, 0.52 parts of 4,4'-dicyclohexylmethane diisocyanate, 0.18 parts of hexamethylene diisocyanate trimer, 28.0 parts of propylene glycol methyl ether propionate, and 6.8 parts of cyclohexanone, mixed and stirred to obtain coating component B;

[0082] The above component A and the above component B are mixed at a mass fraction of 1:1, stirred at 25°C for 2 hours, and allowed to stand for 3 hours to eliminate bubbles, to obtain a dust-resistant transparent polyurethane coating;

[0083] Semiconductor film / PMMA substrate surface modification method: Take 0.2g KH550 silane coupling agent and dissolve it in 6g distilled water and mix well to obtain a modified solution, which is then applied to the substrate surface for modification;

[0084] The anti-dust transparent polyurethane coating is applied to the surface of the modified semiconductor film / PMMA substrate, and after being dried at room temperature, it is cured at 60° C. for 8 hours to obtain an anti-dust transparent polyurethane coating with a hard segment content of 20%.

[0085] Comparative Example 2

[0086] This comparative example provides a dust-resistant transparent polyurethane coating and a preparation method thereof, which is different from Example 1 in that no lubricant is added to the preparation raw materials, and other components, amounts and preparation methods are the same as those in Example 1.

[0087] Comparative Example 3

[0088] This comparative example provides an anti-dust transparent polyurethane coating and a preparation method thereof, which is different from comparative example 1 in that no lubricant is added to the preparation raw materials, and other components, dosages and preparation methods are the same as those in comparative example 1.

[0089] Comparative Example 4

[0090] This comparative example provides a dust-resistant transparent polyurethane coating and a preparation method thereof, which differs from Example 1 in that the amount of lubricant added to the preparation raw materials is 0.06 parts, and the other components, amounts and preparation methods are the same as those in Example 1.

[0091] Comparative Example 5

[0092] This comparative example provides an anti-dust transparent polyurethane coating and a preparation method thereof, which differs from Example 1 in that the prepared anti-dust transparent polyurethane coating is applied to the surface of an unmodified semiconductor film / PMMA substrate, and is cured at 60°C for 8h after being dried at room temperature to obtain an anti-dust transparent polyurethane coating. Other components, amounts and preparation methods are the same as those in Example 1.

[0093] Performance Testing

[0094] The anti-dust transparent polyurethane coatings obtained in Examples 1-3 and Comparative Examples 1-4 were tested as follows:

[0095] Coating adhesion test: According to ASTM D3359-02, the coating adhesion is measured;

[0096] Light transmittance and haze test: in accordance with GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics";

[0097] Coating surface hardness: Test the hardness of the coating surface in accordance with GB / T6739-1196 "Coating hardness pencil test method";

[0098] Wear resistance: According to ASTM F735-11, the test was carried out using a reciprocating sand oscillation abrasion tester (Taber 6160) at a cycle speed of 150 times / min and 100 strokes. The degree of wear was measured by the change in the transmittance and haze of the coating before and after the test, which is expressed in the following table as Δ transmittance / Δ haze;

[0099] Dust resistance: The test ash type is SiO2. The specific test method is: Place the sample to be tested horizontally, sprinkle a sufficiently thick layer of dust (SiO2 with a 500-mesh sieve) evenly on its surface, then slowly vertically shake the sample three times to allow excess dust to fall naturally, and the remaining dust adheres to the surface of the sample. Observe and weigh the weight of the dust remaining on the surface of the sample; the evaluation criteria for dust resistance are as follows:

[0100] Level 0: No dust, dust amount per unit area k≤0.01mg / cm 2 ;

[0101] Level 1: Slight dust, dust per unit area 0.01 <k≤0.05mg / cm 2 ;

[0102] Level 2: Slightly dusty, dust content per unit area 0.05 <k≤0.1mg / cm 2 ;

[0103] Level 3: Moderate dust, dust per unit area 0.1 <k≤0.5mg / cm 2 ;

[0104] Level 4: Severe dust, dust amount per unit area k>0.5mg / cm 2 .

[0105] The properties of the polyurethane coatings prepared in the examples and comparative examples were tested according to the above method, and the results are shown in Table 1;

[0106] Table 1 Performance data of polyurethane coatings prepared in Examples and Comparative Examples

[0107]

[0108] From the contents of Table 1, it can be seen that the adhesion grade of the anti-dust and wear-resistant coatings prepared in Examples 1 to 3 is 5B, the transmittance is greater than 92%, the haze is less than 0.9, and the hardness is 5H. After the Taber 100 stroke friction test, the increase in the transmittance of the coating is basically within 0.5%, the increase in the haze is less than 0.1, and the dust amount per unit area is less than 0.01 mg / cm 2 , with good anti-dust and wear resistance.

[0109] When the preparation method of the anti-dust and wear-resistant coating is adjusted to a one-step method (Comparative Example 1), the hardness of the anti-dust and wear-resistant coating is reduced to 4H, the light transmittance and haze of the coating are slightly increased, and the dust content per unit area is 0.05 mg / cm 2 The dust resistance level is level 1, and the coating surface is obviously stained with dust.

[0110] When the anti-dust and wear-resistant coating is prepared by the prepolymer method but without adding a lubricant (Comparative Example 2), the dust content per unit area of ​​the anti-dust and wear-resistant coating prepared is 0.03 mg / cm 2 The dust resistance level is also level 1, and the coating surface is obviously stained with dust.

[0111] Compared with Example 1, when the preparation method of the anti-dust and wear-resistant coating is a one-step method and no lubricant is added (Comparative Example 3), the hardness of the prepared anti-dust and wear-resistant coating is reduced to 4H, and the dust content per unit area is as high as 0.45 mg / cm 2 , the coating surface is seriously stained with dust.

[0112] Compared with Example 1, when the amount of organic silicon lubricant added in the prepolymer method is less (Comparative Example 4, the amount added is 0.06 parts), the dust amount per unit area of ​​the anti-dust and wear-resistant coating is 0.018 mg / cm 2 , the coating surface is slightly stained with dust.

[0113] When the anti-dust and wear-resistant coating is prepared by the prepolymer method and a silicone lubricant is added (Examples 1-3), the coating hardness is 5H and the dust content per unit area is 0.007 mg / cm 2 The dust resistance level is 0, and the coating surface is almost dust-free; combined Figure 1 It can be clearly seen that the dust-proofing of the anti-dust wear-resistant coating prepared in Example 1 is significantly better than that of the anti-dust wear-resistant coating prepared in Comparative Examples 1 and 3. Therefore, the introduction of the prepolymer method and the silicone lubricant in the present application has a synergistic effect on the anti-dust performance of the coating.

[0114] Furthermore, by introducing the ternary component isophorone diisocyanate trimer, a cross-linked structure is constructed between polyurethane segments, which inhibits the crystallization of polyurethane segments and avoids the increase of haze due to refraction of the crystallization area, while improving the cross-linking density of polyurethane, enhancing the wear resistance of the polyurethane coating, and realizing the simultaneous optimization of the optical properties and wear resistance of the coating. In addition, in this application, a silane coupling modified solution is used to modify the surface of the PMMA substrate, and a chemical bond between the PMMA surface and the polyurethane segments is constructed, which effectively enhances the adhesion of the coating during the coating process of the anti-dust wear-resistant coating, and its adhesion can reach 5B.

[0115] Compared with Example 1, when the prepared anti-dust transparent polyurethane coating is applied to the surface of the unmodified semiconductor film / PMMA substrate (Comparative Example 5), it is cured at 60°C for 8h after being dried at room temperature. The obtained anti-dust transparent polyurethane coating has an adhesion of only 3B.

[0116] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0117] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An anti-dust polyurethane coating, prepared from component A and component B, wherein the mass ratio of component A to component B is 1:1; The component A is prepared from the following raw materials: 4-12 parts by weight of polyol, 0.1-1.5 parts by weight of chain extender, 0.1-0.2 parts by weight of leveling agent, 0.05-0.2 parts by weight of wetting agent, 0.1-0.5 parts by weight of light stabilizer, 0.1-0.5 parts by weight of antioxidant, 0.1-0.5 parts by weight of ultraviolet absorber, 0.1-0.15 parts by weight of lubricant, and 0.01-0.3 parts by weight of catalyst; The component B is prepared from the following raw materials: 25-35 parts by weight of polyurethane prepolymer, 0.5-2 parts by weight of aliphatic diisocyanate, and 0-7 parts by weight of aliphatic triisocyanate; The lubricant is a silicone lubricant; The polyol is a combination of polyolefin polyols of different molecular weights, and the molecular weight range is 1000-3000 g / mol; The preparation method of the polyurethane prepolymer is specifically as follows: The polybutadiene polyol is dehydrated and dissolved in a solvent, and then isocyanate and a catalyst are added for reaction to obtain a polyurethane prepolymer; the isocyanate is selected from isophorone diisocyanate trimer, and the molar ratio of the OH group in the polybutadiene polyol to the NCO group in the isophorone diisocyanate trimer is 1:

3.

2. The anti-dust polyurethane coating according to claim 1, characterized in that: In the preparation process of the polyurethane prepolymer, the catalyst is selected from dibutyltin dilaurate; and the reaction temperature is 60-70° C. and the reaction time is 4-5 hours.

3. The anti-dust polyurethane coating according to claim 1, characterized in that: In the component A, the chain extender is selected from one or both of N,N"-di-tert-butylethylenediamine and triethanolamine; the leveling agent is one or more of a short-chain fluorocarbon modified polymer leveling agent and a modified silane leveling agent; the wetting agent is one or more of a polyether modified siloxane wetting agent; the light stabilizer is 770 light stabilizer; the antioxidant is 1010 antioxidant; the ultraviolet absorber is 531 ultraviolet absorber; and the catalyst is dibutyltin dilaurate.

4. The anti-dust polyurethane coating according to claim 1, characterized in that: The content of the lubricant is 0.12-0.14 parts by weight.

5. The method for preparing the anti-dust polyurethane coating according to claim 1 comprises the following steps: Mix 4-12 parts by weight of a polyol, 0.1-1.5 parts by weight of a chain extender, 0.1-0.2 parts by weight of a leveling agent, 0.05-0.2 parts by weight of a wetting agent, 0.1-0.5 parts by weight of a light stabilizer, 0.1-0.5 parts by weight of an antioxidant, 0.1-0.5 parts by weight of a UV absorber, 0.1-0.15 parts by weight of a lubricant, and 0.01-0.3 parts by weight of a catalyst in a solvent to obtain component A; Mixing 25-35 parts by weight of a polyurethane prepolymer, 0.5-2 parts by weight of an aliphatic diisocyanate, and 0-7 parts by weight of an aliphatic triisocyanate in a solvent to obtain component B; Component A and component B are mixed in a mass ratio of 1:1, reacted, and allowed to stand to obtain an anti-dust polyurethane coating.

6. The preparation method according to claim 5, characterized in that: In the step of obtaining the anti-dust polyurethane coating, the reaction temperature is 18-30° C., the reaction time is 2-4 hours, and the standing time is 2-4 hours.

7. A polyurethane coating, characterized in that: The polyurethane coating is an anti-dust polyurethane coating obtained by coating and film-forming and curing; the anti-dust polyurethane coating is the anti-dust polyurethane coating according to any one of claims 1 to 4 or the anti-dust polyurethane coating prepared by the preparation method according to any one of claims 5 to 6.

8. An organic composite material, comprising a modified substrate and a polyurethane coating composited on the surface of the modified substrate; the polyurethane coating is the polyurethane coating according to claim 7, and the modified substrate is a substrate modified by a silane coupling agent.

9. The organic composite material according to claim 8, characterized in that: The substrate is a semiconductor film / PMMA substrate.

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