A method for preparing a water-vapor-resistant polyurethane coating

Abstract

The application relates to a preparation method of a water-vapor-resistant polyurethane coating and relates to the technical field of polyurethane coating compositions. The preparation method comprises the following steps: (1) uniformly mixing hydroxyl vinyl ether, a filler, four-arm-polyethylene glycol-hydroxyl (4arm-PEG-OH), an auxiliary agent and a solvent to obtain component A; (2) mixing isocyanate and a catalyst to obtain component B; and (3) the component A and the component B constitute the polyurethane coating. The filler comprises nano silicon dioxide, nano talcum powder and / or nano montmorillonite. The prepared polyurethane coating is crosslinked and cured through the hydroxyl group of 4arm-PEG-OH and isocyanate solidification reaction to form a four-dimensional stereoscopic network, the four-dimensional stereoscopic network is filled with micro-nano-level hydrophobic fillers, a low-surface-energy interface is constructed on the coating surface, the heat conduction efficiency is significantly reduced, and heat exchange in the condensation process is synergistically inhibited, so that excellent water-vapor-resistant performance is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane coating compositions, in particular to a preparation method of water-vapor-resistant polyurethane coating. BACKGROUND

[0002] Polyurethane waterproof coating has been widely used in various industrial scenarios, and has excellent performance. For example, some polyurethane waterproof coatings used to coat hot wastewater storage tanks and heat preservation pipelines can withstand 60℃ hot water immersion without easy blistering and peeling. However, when encountering more severe working conditions, such as water vapor with a temperature higher than 100℃ contacting the coating with a temperature lower than the dew point of water vapor, the water vapor will quickly liquefy and release a large amount of latent heat of vaporization. The large amount of heat absorption of the polyurethane waterproof coating can easily cause the distance between polymer chain segments to increase, resulting in swelling, volume expansion and density reduction of the coating, which greatly reduces the actual service life of the coating. SUMMARY

[0003] The present application aims to disclose a preparation method of water-vapor-resistant polyurethane coating to solve one or more technical problems existing in the prior art and provide at least one beneficial option or create conditions.

[0004] The first aspect of the present application provides a preparation method of water-vapor-resistant polyurethane coating.

[0005] The preparation method of the first aspect of the present application comprises the following steps:

[0006] (1) uniformly mixing hydroxy vinyl ether, filler, four-arm-polyethylene glycol-hydroxyl (4arm-PEG-OH), auxiliary agent and solvent to obtain component A;

[0007] (2) mixing isocyanate and catalyst to obtain component B;

[0008] (3) the component A and the component B constitute the polyurethane coating;

[0009] The filler includes nano-silicon dioxide, nano-talc powder and / or nano-montmorillonite.

[0010] 4arm-PEG-OH is a functional polymer integrating star topology and multi-reactivity hydroxyl groups. Compared with linear PEG, 4arm-PEG-OH has higher steric hindrance and lower solution viscosity. When the hydroxyl groups of 4arm-PEG-OH react with isocyanate curing and crosslinking, a four-dimensional network is formed, and the crosslinking density is very high, which can greatly improve the tensile strength. At the same time, nano-silicon dioxide, nano-talc powder and nano-montmorillonite all have hydrophobicity, so the filler uniformly dispersed in component A can fill the pores of the four-dimensional network formed by crosslinking, further improve the compactness, and make it difficult for water vapor to invade into the coating.

[0011] Meanwhile, the polyurethane coating provided by the present application discards the silane coupling agent, avoids the reaction between the amino (-NH2) or epoxy group part of the silane coupling agent and the isocyanate (-NCO) in the polyurethane prepolymer, and causes the reduction of -NCO groups available for the main reaction, thereby affecting the crosslinking density of the coating.

[0012] The prepared polyurethane coating presents a highly dense crosslinking network structure after curing, and forms a composite protection system with physical barrier and heat conduction inhibition functions under the synergistic modification of high-mesh hydrophobic fillers. Specifically:

[0013] (I) The nanoscale hydrophobic fillers are uniformly dispersed and construct a low-surface-energy interface on the surface of the coating, which significantly improves the repellency of water vapor and effectively inhibits its penetration and invasion;

[0014] (II) The low thermal conductivity of the fillers and the micro-nano level heat insulation pore network formed in the coating can significantly reduce the heat conduction efficiency and block the transfer path of latent heat to the inside of the coating during condensation of water vapor;

[0015] (III) The above synergistic effect enables the coating to resist the physical penetration of water vapor while inhibiting the heat exchange in the condensation process, thereby ultimately endowing the polyurethane coating with excellent water vapor erosion resistance and condensation latent heat transfer resistance.

[0016] This system realizes the functional upgrade from "physical barrier" to "heat-mass transfer synergistic inhibition" through material interface design and microstructure regulation, and provides a new technical path for the design of protective coatings that need to periodically face water vapor working conditions.

[0017] In a further application embodiment, the 4arm-PEG-OH has a degree of polymerization of 20-40 kDa; preferably, the 4arm-PEG-OH has a degree of polymerization of 25-38 kDa; more preferably, the 4arm-PEG-OH has a degree of polymerization of 30-35 kDa.

[0018] In a further application embodiment, the hydroxyvinyl ether includes 4-hydroxybutyl vinyl ether and / or triethylene glycol divinyl ether.

[0019] In a further application embodiment, the isocyanate comprises at least one of hydrogenated phenylmethane diisocyanate (hydrogenated MDI), toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), hexamethylene diisocyanate (HDI); further preferably hydrogenated phenylmethane diisocyanate, toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI). The use of isocyanates containing benzene rings for cross-linking and curing helps to improve the density of the coating layer. Hydrogenated phenylmethane diisocyanate also makes the coating have better yellowing resistance.

[0020] In a further application embodiment, the catalyst comprises organotin, such as dibutyltin dilaurate, di(dodecylthio) dibutyltin.

[0021] In a further application embodiment, the auxiliary agent comprises at least one of defoaming agent, sodium lauryl sulfate, nonylphenol polyethylene glycol.

[0022] In a further application embodiment, the defoaming agent is polydimethylsiloxane.

[0023] In a further application embodiment, the solvent comprises ethanol and water. For example, the solvent is composed of ethanol and water in a mass ratio of 1: (0.5-3).

[0024] In a further application embodiment, the mass ratio of hydroxy vinyl ether, filler, 4arm-PEG-OH is 1: (0.5-1.5): (1-3); preferably, the mass ratio of the three is 1: (0.8-1.4): (1.5-2).

[0025] In a further application embodiment, the mass ratio of hydroxy vinyl ether, auxiliary agent and solvent is 1: (1-5): (8-50); preferably, the mass ratio of the three is 1: (2-5): (10-40).

[0026] In a further application embodiment, in component B, the mass ratio of isocyanate to catalyst is 1: (0.1-0.5); preferably, the mass ratio of isocyanate to catalyst is 1: (0.1-0.3).

[0027] In a further application embodiment, the mass ratio of component A to component B is 10: (0.1-2); preferably, the further mass ratio is 10: (0.5-1.8).

[0028] In a further application embodiment, the specific steps of the preparation method comprise:

[0029] (1) mixing hydroxy vinyl ether, filler, 4arm-PEG-OH, auxiliary agent, solvent uniformly to obtain component A, the mass ratio of the hydroxy vinyl ether, filler, 4arm-PEG-OH is 1:(0.5~1.5):(1~3);

[0030] (2) mixing isocyanate, catalyst to obtain component B, the mass ratio of the isocyanate and catalyst is 1:(0.1~0.5);

[0031] (3) the component A and component B constitute the polyurethane coating, the mass ratio of the component A and component B is 10:(0.1~2);

[0032] The filler includes nanosilica, nanotalc and / or nanomontmorillonite.

[0033] The water vapor resistant polyurethane coating prepared by the preparation method is mixed with component A and component B during use, and then cured to obtain a polyurethane coating.

[0034] Preferably, the curing temperature is 40~100℃, and the curing time is 60~150 minutes; further preferably, the curing temperature is 50~90℃, and the curing time is 70~120 minutes.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] The polyurethane coating is a two-component coating, which utilizes hydroxy vinyl ether, filler, 4arm-PEG-OH, auxiliary agent and solvent to form component A, and isocyanate and catalyst to form component B. During use, component A and component B are mixed and cured to form a polyurethane coating layer. The hydroxyl group of 4arm-PEG-OH and isocyanate curing crosslinking reaction will form a four-dimensional network, and the micro-nano level hydrophobic filler fills the four-dimensional network, which not only constructs a low surface energy interface on the surface of the coating, but also significantly reduces the heat conduction efficiency, and can also synergistically inhibit the heat exchange in the condensation process, thereby obtaining excellent water vapor resistance. DETAILED DESCRIPTION

[0037] In the description of the present application, if the first, second, etc. are described, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0038] The words "preferably," "more preferably," and the like, where used herein, mean that in certain situations, one embodiment of the application can provide certain benefits, however, other embodiments can also provide such benefits and, therefore, the words are not intended to narrow the scope of the claims and are not intended to dictate an order of significance of the recited features. Moreover, the recitation of one or more preferred embodiments does not imply that other embodiments are less preferred.

[0039] When a numerical range is disclosed herein, the range is continuous and includes the minimum and maximum values, as well as each integer within the range. Further, where a range is provided, any intervening range is also contemplated. In other words, a range of "1 to 5" is intended to capture a range of "1 to 5," a range of "3 to 4," a range of "2 to 4," a range of "2 to 3," a range of "3 to 5," a range of "1 to 3," a range of "1 to 2," a range of "4 to 5," and the like.

[0040] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0041] The reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the technical field unless otherwise specified.

[0042] Example 1, preparation of polyurethane coating No. 1

[0043] The preparation method comprises the following steps:

[0044] (1) 10 parts of 4-hydroxybutyl vinyl ether, 6 parts of nano-talc powder, 6 parts of nano-silicon dioxide, 18 parts of 4arm-PEG-OH with a polymerization degree of about 30 kDa, 10 parts of polydimethylsiloxane and 10 parts of sodium lauryl sulfate are added into 200 parts of 55% ethanol solution, the stirring speed during mixing is 1000 rpm, and the stirring is continued for 20 minutes to obtain component A;

[0045] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate are mixed, the stirring speed during mixing is 200 rpm, and the stirring is continued for 10 minutes to obtain component B;

[0046] (3) Component A and component B constitute the polyurethane coating, and the mass ratio is 10:1.03.

[0047] Example 2, preparation of polyurethane coating No. 2

[0048] The preparation method comprises the following steps:

[0049] (1) 10 parts of triethylene glycol divinyl ether, 7 parts of nano-montmorillonite, 15 parts of 4arm-PEG-OH with a polymerization degree of about 20 kDa, 9 parts of polydimethylsiloxane and 9 parts of sodium lauryl sulfate are added into 250 parts of 60% ethanol solution, the stirring speed is 800 rpm during mixing, and stirring is continuously performed for 30 minutes to obtain component A;

[0050] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate are mixed, the stirring speed is 200 rpm during mixing, and stirring is continuously performed for 10 minutes to obtain component B;

[0051] (3) Component A and component B constitute a polyurethane coating, and the mass ratio is 10:0.89.

[0052] Example 3, preparation of No. 3 polyurethane coating

[0053] The preparation method comprises the following steps:

[0054] (1) 10 parts of 4-hydroxybutyl vinyl ether, 14 parts of nano-silicon dioxide, 20 parts of 4arm-PEG-OH with a polymerization degree of about 40 kDa, 6 parts of polydimethylsiloxane and 14 parts of sodium lauryl sulfate are added into 300 parts of 50% ethanol solution, the stirring speed is 1000 rpm during mixing, and stirring is continuously performed for 30 minutes to obtain component A;

[0055] (2) 38.5 parts of TDI and 3.85 parts of dibutyltin dilaurate are mixed, the stirring speed is 200 rpm during mixing, and stirring is continuously performed for 10 minutes to obtain component B;

[0056] (3) Component A and component B constitute a polyurethane coating, and the mass ratio is 10:1.16.

[0057] Example 4, preparation of No. 4 polyurethane coating

[0058] The preparation method comprises the following steps:

[0059] (1) 5 parts of 4-hydroxybutyl vinyl ether, 5 parts of triethylene glycol divinyl ether, 12 parts of nano-montmorillonite, 13 parts of 4arm-PEG-OH with a polymerization degree of about 35 kDa, 10 parts of polydimethylsiloxane and 8 parts of sodium lauryl sulfate are added into 220 parts of 55% ethanol solution, the stirring speed is 700 rpm during mixing, and stirring is continuously performed for 30 minutes to obtain component A;

[0060] (2) 23.5 parts of hydrogenated MDI and 3.53 parts of dibutyltin dilaurate are mixed, the stirring speed during mixing is 200 rpm, and stirring is continued for 10 minutes to obtain component B;

[0061] (3) Component A and component B constitute the polyurethane coating, and the mass ratio of component A to component B is 10:0.99.

[0062] Comparative Example 1, preparation of No. 1 control polyurethane coating

[0063] The prior art has prepared a polyurethane waterproof coating that can resist hot water immersion at 60℃ without being prone to blistering and peeling, and the water-resistant polyurethane coating prepared according to the disclosed technical solution is used to conduct a control experiment with the water-vapor-resistant polyurethane coating described in the present application.

[0064] The preparation method comprises the following steps:

[0065] (1) 4-hydroxybutyl vinyl ether, composite alcohol, silane coupling agent KH570, polyether triol and hydroxymethyl cellulose are mixed, the stirring speed during mixing is 800 rpm, and stirring is continued for 30 minutes, then the filler (the filler is composed of nano silicon dioxide and nano calcium silicate at a mass ratio of 1:2), hydroxyl-terminated polybutadiene, the auxiliary agent (the auxiliary agent is composed of polydimethylsiloxane and sodium lauryl sulfate at a mass ratio of 1:1), and the solvent (ethanol and water are mixed at a mass ratio of 1:0.8 to form the solvent) are mixed, the stirring speed during mixing is 1000 rpm, and stirring is continued for 20 minutes to obtain component A;

[0066] The mass ratio of 4-hydroxybutyl vinyl ether, composite alcohol, silane coupling agent, filler and hydroxyl-terminated polybutadiene is 1:0.8:2:1.5:1; the mass ratio of 4-hydroxybutyl vinyl ether, auxiliary agent and solvent is 1:2:20;

[0067] The composite alcohol is composed of the following components by mass fraction: 1 part of glycerol, and 3 parts of xylitol, 2 parts of sorbitol and 3 parts of pentaerythritol;

[0068] The mass ratio of 4-hydroxybutyl vinyl ether, polyether triol and hydroxymethyl cellulose is 1:0.3:0.4;

[0069] (2) Isocyanate (TDI) and catalyst (dibutyltin dilaurate) are mixed, the stirring speed during mixing is 200 rpm, and stirring is continued for 10 minutes to obtain component B, and the mass ratio of isocyanate to catalyst is 1:0.1;

[0070] (3) Component A and component B constitute the polyurethane coating, and the mass ratio of component A to component B is 10:0.8.

[0071] The difference between Comparative Example 1 and Example 1 is that: I. In Example 1, no specific polyol and hydroxyl-terminated polybutadiene is used, but the hydroxyl group provided by 4arm-PEG-OH is used to react with the isocyanate group by nucleophilic addition reaction; II. The total proportion of the filler used in Example 1 in component A is about 4.62%, and is limited to nano-talc and nano-silicon dioxide, and the total proportion of the filler used in Comparative Example 1 in component A is about 5.30%, and is limited to nano-silicon dioxide and nano-calcium silicate; III. Example 1 does not use silane coupling agent KH570 and hydroxymethyl cellulose.

[0072] Preparation of Comparative Example 2, No. 2 control polyurethane coating

[0073] Comparative Example 2 is only different from Example 1 in that an equal amount of pentaerythritol is used instead of 4arm-PEG-OH in Example 1, and the rest of the process is the same as Example 1.

[0074] The preparation method comprises the following steps:

[0075] (1) 10 parts of 4-hydroxybutyl vinyl ether, 6 parts of nano-talc, 6 parts of nano-silicon dioxide, 18 parts of pentaerythritol, 10 parts of polydimethylsiloxane and 10 parts of sodium lauryl sulfate are added to 200 parts of 55% ethanol solution, the stirring speed during mixing is 1000 rpm, and the stirring is continued for 20 minutes to obtain component A;

[0076] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate are mixed, the stirring speed during mixing is 200 rpm, and the stirring is continued for 10 minutes to obtain component B;

[0077] (3) Component A and component B constitute a polyurethane coating.

[0078] Preparation of Comparative Example 3, No. 3 control polyurethane coating

[0079] Comparative Example 3 is only different from Example 1 in that the degree of polymerization of 4arm-PEG-OH used is about 15kDa, and the rest of the process is the same as Example 1.

[0080] The preparation method comprises the following steps:

[0081] (1) 10 parts of 4-hydroxybutyl vinyl ether, 6 parts of nano-talc, 6 parts of nano-silicon dioxide, 18 parts of pentaerythritol, 10 parts of polydimethylsiloxane and 10 parts of sodium lauryl sulfate are added to 200 parts of 55% ethanol solution, the stirring speed during mixing is 1000 rpm, and the stirring is continued for 20 minutes to obtain component A;

[0082] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate were mixed, the stirring speed during mixing was 200 rpm, and stirring was continued for 10 minutes to obtain component B;

[0083] (3) Component A and component B constituted the polyurethane coating.

[0084] Comparative Example 4, preparation of No. 4 control polyurethane coating

[0085] Comparative Example 4 differs from Example 1 only in that the 4arm-PEG-OH used has a degree of polymerization of about 60 kDa, and the rest of the process is the same as in Example 1.

[0086] The preparation method comprises the following steps:

[0087] (1) 10 parts of 4-hydroxybutyl vinyl ether, 6 parts of nano-talc, 6 parts of nano-silicon dioxide, 18 parts of 4arm-PEG-OH with a degree of polymerization of about 60 kDa, 10 parts of polydimethylsiloxane and 10 parts of sodium lauryl sulfate were added to 200 parts of 55% ethanol solution, the stirring speed during mixing was 1000 rpm, and stirring was continued for 20 minutes to obtain component A;

[0088] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate were mixed, the stirring speed during mixing was 200 rpm, and stirring was continued for 10 minutes to obtain component B;

[0089] (3) Component A and component B constituted the polyurethane coating.

[0090] Comparative Example 5, preparation of No. 5 control polyurethane coating

[0091] Comparative Example 5 differs from Example 1 in that silane coupling agent KH570 was added on the basis of Example 1, and the rest of the process is the same as in Example 1.

[0092] The preparation method comprises the following steps:

[0093] (1) 10 parts of 4-hydroxybutyl vinyl ether, 6 parts of nano-talc, 6 parts of nano-silicon dioxide, 18 parts of 4arm-PEG-OH, 20 parts of silane coupling agent KH570, 10 parts of polydimethylsiloxane and 10 parts of sodium lauryl sulfate were added to 200 parts of 55% ethanol solution, the stirring speed during mixing was 1000 rpm, and stirring was continued for 20 minutes to obtain component A;

[0094] (2) 22.3 parts of MDI and 4.45 parts of dibutyltin dilaurate were mixed, the stirring speed during mixing was 200 rpm, and stirring was continued for 10 minutes to obtain component B;

[0095] (3) Component A and Component B form a polyurethane coating.

[0096] Example 5, Polyurethane Coating Control Test

[0097] The polyurethane resin coatings prepared in the above Examples 1-4 and Comparative Examples 1-5 were coated (coating amount: 0.5 mg / cm 2 ) on glass substrates and cured to obtain samples. Three parallel samples were prepared for each group, and were fixed in a pipeline for water vapor circulation treatment, each cycle including continuous water vapor input into the pipeline for 5 minutes, and then ventilation cooling for 10 minutes. The average number of times (the decimal part was discarded) that each group of samples could withstand water vapor circulation treatment without bubbling within 72 hours was recorded.

[0098] The equipment in the actual use scenario that needs to apply a polyurethane waterproof coating is located near the water vapor exhaust port, and needs to withstand the influence of 3 times of water vapor exhaust every day and cannot be avoided, and the rest of the time is in a free cooling state to the ambient temperature. The above water vapor circulation treatment is an accelerated simulation of the actual use scenario, and the 5-minute water vapor input time is consistent with the actual use scenario, and the ventilation cooling is to accelerate the simulation of the natural cooling of the equipment. The 72-hour experiment is equivalent to 96 days of working conditions in the actual use scenario. The results are shown in Table 1.

[0099] Table 1, Water Vapor Circulation Treatment Resistance Test Results

[0100]

[0101] As can be seen from Table 1, the water vapor resistant polyurethane coating provided by the present application can remain for more than 90 days in the above working conditions, meeting the equipment maintenance interval period. The service life of the No. 2 polyurethane coating is slightly shorter, which is inferred to be due to the lower proportion of fillers in Component A, which causes water vapor to gradually invade some micropores, and finally the corner area of the sample first appears bubbles.

[0102] Comparative Example 1 is the optimal example disclosed in the prior art, and its water absorption rate in distilled water at 60°C for 48 hours is only 0.2%. But in this resistance experiment, it only lasted for 135 cycles before it started to bubble. The possible reason is related to the hydroxymethyl cellulose therein. In hot water at 60°C, water molecules still maintain a state of aggregation and are not easy to enter the coating; water molecules in water vapor are in a dispersed state and are more likely to enter the micropores of the coating. Even though the proportion of hydrophobic fillers in Comparative Example 1 is higher, the water-soluble hydroxymethyl cellulose therein is still affected by water molecules, causing the coating structure to gradually develop leaks, so it cannot be tested by experiment.

[0103] Comparative Example 2 provides hydroxyl groups for the precursor of 4arm-PEG-OH, but the polyurethane coating prepared has poor performance. In combination with Comparative Examples 3 and 4, it is possible that the lack of PEG chains of suitable degree of polymerization makes it difficult for the filler to embed in the four-dimensional network, making it difficult to improve the compactness and hydrophobicity of the coating. Comparative Example 4 may be due to the PEG chain being too long, making the filling effect of the filler poor, or it may be due to the crystallization of the long PEG chain during polymerization, resulting in an increase in material rigidity.

[0104] Comparative Example 5 additionally adds silane coupling agent KH570, but instead results in poor performance in water vapor resistant working conditions. The reason may be that the amino or epoxy groups in the silane coupling agent may partially react with the isocyanate in the polyurethane prepolymer, resulting in a decrease in the -NCO groups available for the main reaction, thereby affecting the crosslinking density of the coating, and thus making it difficult to further improve the performance of the coating in resisting water vapor erosion.

[0105] It will be apparent to those skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A method for preparing a water vapor resistant polyurethane coating, characterized by, The method comprises the following steps: (1) mixing hydroxy vinyl ether, filler, four-arm-polyethylene glycol-hydroxyl, auxiliary agent, and solvent uniformly to obtain component A; (2) mixing isocyanate and catalyst to obtain component B; (3) the component A and the component B constitute the polyurethane coating. The filler comprises nanosilica, nanometer talcum powder and / or nanometer montmorillonite, the polymerization degree of the four-arm-polyethylene glycol-hydroxyl is 20-40 kDa, and the polyurethane coating does not comprise a silane coupling agent.

2. The method of claim 1, wherein, The hydroxy vinyl ether comprises 4-hydroxybutyl vinyl ether and / or triethylene glycol divinyl ether.

3. The preparation method according to claim 1, characterized in that, The isocyanate comprises at least one of hydrogenated phenylmethane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, and hexamethylene diisocyanate.

4. The preparation method according to claim 1, characterized in that, The auxiliary agent comprises at least one of defoaming agent, sodium lauryl sulfate, and nonylphenol polyethylene glycol.

5. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The mass ratio of the hydroxy vinyl ether, filler and four-arm-polyethylene glycol-hydroxyl is 1:(0.5-1.5):(0.15-1.5).

6. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The mass ratio of the hydroxy vinyl ether, auxiliary agent and solvent is 1:(1-5):(8-50).

7. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. In the component B, the mass ratio of the isocyanate and catalyst is 1:(0.1-0.5).

8. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The mass ratio of the component A and the component B is 10:(0.1-2).

9. The method of claim 1, wherein the step of forming the first and second layers is performed by a process selected from the group consisting of: sputtering, evaporation, and chemical vapor deposition. The method comprises the following steps: (1) mixing hydroxy vinyl ether, filler, four-arm-polyethylene glycol-hydroxyl, auxiliary agent, and solvent uniformly to obtain component A, and the mass ratio of the hydroxy vinyl ether, filler and four-arm-polyethylene glycol-hydroxyl is 1:(0.5-1.5):(1-3); (2) mixing isocyanate and catalyst to obtain component B, and the mass ratio of the isocyanate and catalyst is 1:(0.1-0.5); (3) the component A and the component B constitute the polyurethane coating, and the mass ratio of the component A and the component B is 10:(0.1-2); The filler comprises nanosilica, nanometer talcum powder and / or nanometer montmorillonite.

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