Leveling agent suitable for high-optical parts and preparation method and application thereof

Abstract

The invention provides a preparation method of a flatting agent applicable to high-optical parts, which comprises the following step: carrying out esterification reaction in the presence of mono-or dihydroxy-terminated organic silicon resin, functional ionic liquid, a catalyst and a solvent to obtain the flatting agent. The novel flatting agent is obtained by carrying out esterification reaction on double-terminal hydroxyl organic silicon and functional ionic liquid according to the molecular molar ratio of 1: 1 to generate monohydroxyl organic silicon ionic liquid, one end of the flatting agent has relatively large surface tension, the other end of the flatting agent has relatively low surface tension, the flatting agent is not completely mixed and dissolved with polyurethane resin, and the flatting agent is not easy to dissolve. A monomolecular layer can be rapidly formed on the surface of a wet film, and the surface flowing capacity is improved; the monohydroxyl group of the leveling agent can also anchor the organic silicon to the surface of the polyurethane coating, so that the surface is smooth and is not sticky with dust.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a leveling agent suitable for high-optical parts, a preparation method thereof, and an application thereof. Background Art

[0002] Transparent parts of modern aircraft are mostly made of optical plastic integral molding. The coating on multi-angle curved hatches is usually prepared by curtain coating. Under the action of gravity, it is difficult for conventional coatings on the market to have a good leveling effect. Even if the coating is visually smooth and transparent, optical defects such as orange peel, ripples, and flow marks will still exist under slide projection.

[0003] Aircraft transparent components are crucial for pilot safety. Optical parameters such as high light transmittance, low haze, and low optical distortion are essential for ensuring quick and accurate judgment. Modern aircraft transparent components are often manufactured from integrally molded optical plastics. While these components offer numerous advantages over glass, such as light weight, strong impact resistance, and low production costs, they suffer from low surface hardness, susceptibility to scratching, and difficulty withstanding high-speed erosion from wind, sand, and ice crystals. Applying a wear-resistant polyurethane protective coating to the optical plastics overcomes these drawbacks.

[0004] As with optical components, protective coatings for transparent parts have extremely high requirements for optical defects such as craters, flow marks, and orange peel. Furthermore, they must exhibit zero optical distortion at 30 degrees, ensuring accurate pilot judgment during takeoff and landing, as well as during aircraft operation. Good optical leveling is essential for protective coatings applied to transparent parts. Common wood paints, car paints, and varnishes, which have lower optical requirements, are difficult to apply to transparent parts with complex curvatures.

[0005] For curved optical coatings, the current problem is not only the mismatch between the coating reaction rate and the solvent evaporation rate, but the more important reason is that during the coating flow process, the high-viscosity wet film has insufficient leveling power, and the required leveling time is greater than the flow time, thus forming optical problems such as flow marks.

[0006] Currently, there is no optical coating specifically prepared for large-scale optical parts. Existing coatings applied on optical organic glass, especially on the surface of large-scale transparent parts with complex curvature, are very likely to produce optical defects such as flow marks and ripples. More serious optical problems may also exist, such as shrinkage holes, orange peel, and sagging. After passing through the optical defect coating, light deviates and causes light distortion, thereby deforming the image and hindering the pilot's accurate judgment.

[0007] Selecting existing leveling agents, silicone leveling agents reduce surface tension and have a good wetting effect, but cannot provide sufficient leveling power for high-viscosity wet films; while acrylic leveling agents have higher compatibility due to their higher surface tension, and cannot migrate quickly to the wet film surface. Acrylic leveling agents that can migrate quickly have relatively low surface tension and cannot achieve a good leveling effect.

[0008] Therefore, it is very important to provide a leveling agent that can quickly level the coating on the surface of a transparent part with complex curvature, and the prepared coating has no optical defects when projected at an angle greater than 30° and does not produce light distortion. Summary of the Invention

[0009] In view of this, the technical problem to be solved by the present invention is to provide a leveling agent for high optical parts. The leveling agent provided by the present invention can quickly level the surface of transparent parts with complex curvatures. The prepared coating has no optical defects when projected at an angle greater than 30° and does not produce light distortion.

[0010] The present invention provides a method for preparing a leveling agent suitable for high optical components, comprising the following steps:

[0011] The product is obtained by carrying out esterification reaction in the presence of mono- or di-terminal hydroxyl organic silicone resin, functional ionic liquid, catalyst and solvent.

[0012] In some specific embodiments, the double-terminated hydroxyl silicone resin is Silok8802F.

[0013] In some specific embodiments, the cation in the functional ionic liquid comprises one or more of a hydroxyl group, an amino group, and a carboxyl group; and the functional ionic liquid is 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0014] In some specific embodiments, the catalyst is concentrated sulfuric acid or tetrabutyl titanate;

[0015] The solvent includes toluene or xylene.

[0016] In some specific embodiments, the molar ratio of the mono- or di-terminated hydroxyl silicone resin and the functional ionic liquid is 1:1;

[0017] The mass of the solvent is 1% to 100% of the total mass of the mono- or di-terminated hydroxyl organic silicone resin, the functional ionic liquid, the catalyst and the solvent;

[0018] The mass of the catalyst is 0.01% to 1% of the total mass of the mono- or di-terminated hydroxyl organic silicon resin, the functional ionic liquid, the catalyst and the solvent.

[0019] In some specific embodiments, the esterification reaction temperature is 70-100° C. and the time is 2-10 h;

[0020] During the esterification reaction, nitrogen was purged and water was removed by condensation.

[0021] The present invention provides a leveling agent suitable for high optical components, which is prepared by the preparation method described in any one of the above technical solutions.

[0022] The present invention provides an optical leveling polyurethane protective coating, comprising a coating component A and a coating component B, wherein the coating component A comprises a polyol, a chain extender, a catalyst, a solvent, a leveling agent prepared by the preparation method according to any one of claims 1 to 7, and a light stabilizer; and the coating component B is an aliphatic diisocyanate or trimer.

[0023] The aliphatic diisocyanates of the present invention include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, HDI trimer, and IPDI trimer.

[0024] In some specific embodiments, the mass of the leveling agent is 0.1-0.5% of the mass percentage of the optical leveling polyurethane protective coating.

[0025] The present invention provides a method for preparing the optical leveling polyurethane protective coating described in the above technical solution, comprising the following steps:

[0026] Mix the coating component A and the coating component B, stir and react, filter, let stand to remove bubbles, apply the coating to the organic glass by vertical spray coating, and solidify after leveling and surface drying.

[0027] Compared to the prior art, the present invention provides a method for preparing a leveling agent suitable for transparent coatings with high optical requirements, comprising the following steps: conducting an esterification reaction in the presence of a mono- or di-hydroxyl-terminated organosilicon resin, a functional ionic liquid, a catalyst, and a solvent. The present invention generates a monohydroxyl organosilicon ionic liquid by esterifying the di-hydroxyl-terminated organosilicon with the functional ionic liquid in a molecular molar ratio of 1:1. This novel leveling agent has a high surface tension at one end and a low surface tension at the other end. It is incompletely miscible with the polyurethane resin and can quickly form a monolayer on the surface of a wet film, improving surface flowability. The monohydroxyl group in the leveling agent also anchors the organosilicon to the polyurethane coating surface, achieving smooth and dust-resistant surface properties.

[0028] The present invention can not only be applied to protective coatings for transparent parts, but can also be expanded to be applied to lens, automobile or high-speed rail glass protection, etc., which have high requirements on optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart for preparing the leveling agent of the present invention;

[0030] Figure 2This is the NMR comparison diagram of Example 1;

[0031] Figure 3 This is the NMR integral image of the reaction results of Example 1;

[0032] Figure 4 The leveling effect of the coating prepared in the examples (photos projected at a 30° angle on a slide); (a) Example 1; (b) Example 2; (c) Example 3;

[0033] Figure 5 Leveling effects of coatings prepared for comparative examples (slide projection photos at a 30° angle) (d) Comparative Example 1; (e) Comparative Example 2; (f) Comparative Example 3; (g) Comparative Example 4. DETAILED DESCRIPTION

[0034] The present invention provides a leveling agent suitable for high-optical components, as well as its preparation method and application. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve the desired effect. It is particularly important to note that all similar substitutions and modifications are obvious to those skilled in the art and fall within the scope of protection of 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.

[0035] The present invention provides a method for preparing a leveling agent suitable for high optical components, comprising the following steps:

[0036] The product is obtained by carrying out esterification reaction in the presence of mono- or di-terminal hydroxyl organic silicone resin, functional ionic liquid, catalyst and solvent.

[0037] The present invention provides a method for preparing a leveling agent suitable for coatings with high optical requirements. The method comprises the following steps: pouring a mono- or di-terminated hydroxyl silicone resin, a functional ionic liquid, a catalyst, and a solvent into a stirred reaction vessel in proportion, controlling the temperature for reaction, purging with nitrogen during the reaction, and removing water by condensation to obtain the leveling agent.

[0038] The raw materials of the present invention include mono- or di-terminal hydroxyl organosilicon resins, preferably di-terminal hydroxyl organosilicon resins.

[0039] In some specific embodiments, the dual-terminated hydroxyl silicone resin is preferably Silok8802F.

[0040]

[0041] In some specific embodiments, the cation in the functionalized ionic liquid comprises one or more of a hydroxyl group, an amino group, and a carboxyl group; the anion of the functionalized ionic liquid is preferably bis(trifluoromethanesulfonyl)imide; and the functionalized ionic liquid of the present invention is particularly preferably 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

[0042] In some specific embodiments, the catalyst is concentrated sulfuric acid or tetrabutyl titanate; the present invention preferably uses concentrated sulfuric acid as the catalyst.

[0043] According to the present invention, the solvent is any organic solvent well known to those skilled in the art without any particular limitation. In the present invention, the solvent preferably includes but is not limited to toluene and other solvents that do not participate in the esterification reaction.

[0044] In some specific embodiments, the molar ratio of the mono- or di-terminated hydroxyl silicone resin to the functional ionic liquid is 1:(0.5-1); specifically, it can be: 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, or 1:1.

[0045] The mass of the solvent is 1%-100% of the total mass of the mono- or di-terminated hydroxyl silicone resin, the functional ionic liquid, the catalyst and the solvent; specifically, it can be 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%.

[0046] The mass of the catalyst is 0.01% to 1% of the total mass of the mono- or di-terminated hydroxyl organosilicon resin, the functional ionic liquid, the catalyst, and the solvent, and specifically can be 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%.

[0047] In some specific schemes, the esterification reaction temperature is 70-100°C, specifically 70°C, 80°C, 90°C, 100°C; the time is 2-10h, specifically 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h; or a range between any two of the above.

[0048] The protective atmosphere during the esterification reaction can be any protective atmosphere well known to those skilled in the art without any particular limitation. In the present invention, nitrogen is preferably used; that is, nitrogen is purged and water is removed by condensation.

[0049] The present invention has no particular limitation on the sources of all raw materials, and any commercially available raw materials may be used.

[0050] The present invention conducts an esterification reaction between a double-terminal hydroxyl group organic silicon and 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt at a molecular molar ratio of 1:1 to generate a monohydroxyl organic silicon ionic liquid, thereby obtaining a novel leveling agent. The leveling agent has a large surface tension at one end and a low surface tension at the other end, is incompletely miscible with the polyurethane resin, can quickly form a monomolecular layer on the surface of a wet film, and improves the surface flowability. The monohydroxyl group of the leveling agent can also anchor the organic silicon to the surface of the polyurethane coating, thereby achieving surface smoothness and dust-proof properties.

[0051] The present invention provides a leveling agent suitable for coatings with high optical requirements, which is prepared by the preparation method described in any one of the above technical solutions.

[0052] The present invention has clearly described the preparation method of the leveling agent for the coating with high optical requirements, and no limitation is given here.

[0053] The present invention provides an optical leveling polyurethane protective coating, comprising a coating component A and a coating component B, wherein the coating component A comprises a polyol, a chain extender, a catalyst, a solvent, an antioxidant, an ultraviolet absorber, a light stabilizer, and a leveling agent prepared by the preparation method described in any one of the above technical solutions; and the coating component B is an aliphatic diisocyanate or trimer.

[0054] The polyol polymer of the present invention can be any polyol polymer well known to those skilled in the art without any special limitation. In a specific embodiment provided by the present invention, the polyol polymer preferably includes but is not limited to one or more of polycaprolactone polyol, polycarbonate and polyether polyol, more preferably polycaprolactone diol PCL210N.

[0055] The aliphatic diisocyanates of the present invention include hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, HDI trimer, and IPDI trimer.

[0056] In a specific embodiment provided by the present invention, the mass of the polyol is preferably 20-40% of the optical leveling polyurethane protective coating.

[0057] The chain extender can be any chain extender well known to those skilled in the art without any particular limitation. In a specific embodiment provided by the present invention, the chain extender is preferably 1,2,4-butanetriol.

[0058] In a specific embodiment provided by the present invention, the mass of the chain extender is preferably 1-5% of the optical leveling polyurethane protective coating, specifically 1%, 2%, 3%, 4% or 5%.

[0059] The present invention does not limit the catalyst, which may be an organic tin catalyst. The organic tin catalyst is preferably one or more of dibutyltin dilaurate, stannous octoate and triethylenediamine.

[0060] In a specific embodiment provided by the present invention, the mass of the catalyst is preferably 0.01%-1% of the optical leveling polyurethane protective coating, specifically 0.01%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%.

[0061] The light stabilizer of the present invention is any light stabilizer well known to those skilled in the art and is not particularly limited. In the present invention, UV770 is preferred. The mass of the light stabilizer is preferably 0.1%-0.5% of the optical leveling polyurethane protective coating.

[0062] The solvent of the present invention is any organic solvent well known to those skilled in the art and is not particularly limited. In the present invention, butyl acetate and N,N-dimethylformamide are preferred. The mass ratio of butyl acetate to N,N-dimethylformamide is preferably 1: (1-2).

[0063] The above-mentioned leveling agent of the present invention is the leveling agent described in the above technical solution, and the present invention will not repeat it any more.

[0064] In some specific solutions, the mass of the leveling agent is 0.1%-0.5% of the mass percentage of the optical leveling polyurethane protective coating; specifically, it can be 0.1%, 0.2%, 0.3%, 0.4%, or 0.5%.

[0065] The aliphatic diisocyanate or trimer of the present invention is any aliphatic diisocyanate or trimer known to those skilled in the art without any particular limitation. In the present invention, the aliphatic diisocyanate or trimer preferably includes but is not limited to one or more of a trimer of hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0066] In some specific embodiments, the mass of the aliphatic diisocyanate or trimer is 10%-20% by mass of the optical leveling polyurethane protective coating; specifically, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0067] The present invention provides a method for preparing the optical leveling polyurethane protective coating described in the above technical solution, comprising the following steps:

[0068] Mix the coating component A and the coating component B, stir and react, filter, let stand to remove bubbles, apply the coating to the organic glass by vertical spray coating, and solidify after leveling and surface drying.

[0069] In the present invention, the coating component A and the coating component B are first mixed and stirred for reaction; the mixing method is a method well known to those skilled in the art and is not particularly limited. In the present invention, stirring is preferred; the mixing time is preferably 10 to 60 minutes, more preferably 20 to 50 minutes, further preferably 25 to 40 minutes, and most preferably 30 minutes.

[0070] After mixing and stirring, the mixture is filtered, and the filtration is positive pressure filtration; the standing time is preferably 20 to 40 minutes, preferably 30 minutes. The function of the standing time in the present invention is to remove bubbles.

[0071] The coating is applied to the organic glass by vertical flow coating. After leveling and surface drying, the product is transferred to a forced air drying oven for curing.

[0072] The present invention synthesizes a leveling agent with an amphiphilic structure and applies it to optical polyurethane coatings, significantly improving the leveling performance of polyurethane optical coatings. The present invention can achieve high leveling of the coating without extending the coating's surface drying time or affecting the coating's thickness.

[0073] The present invention also provides the use of the optical leveling polyurethane protective coating in preparing a protective coating for a transparent part.

[0074] The present invention also provides an aircraft transparent part coating, which is prepared from an optical leveling polyurethane protective coating.

[0075] The present invention can not only be applied to protective coatings for transparent parts, but can also be expanded to be applied to lens, automobile or high-speed rail glass protection, etc., which have high requirements on optical properties.

[0076] The present invention provides a method for preparing a leveling agent suitable for high-optical components, comprising the following steps: conducting an esterification reaction in the presence of a mono- or di-hydroxyl-terminated organosilicon resin, a functional ionic liquid, a catalyst, and a solvent. The present invention generates a monohydroxyl organosilicon ionic liquid by esterifying the di-hydroxyl-terminated organosilicon with a functional ionic liquid in a molecular molar ratio of 1:1. This novel leveling agent has a high surface tension at one end and a low surface tension at the other end. The leveling agent is incompletely miscible with the polyurethane resin and can quickly form a monolayer on the surface of a wet film, improving surface flowability. The monohydroxyl group in the leveling agent also anchors the organosilicon to the surface of the polyurethane coating, achieving smooth and dust-resistant surface properties.

[0077] This invention prepares a leveling agent for polyurethane coatings. The amphiphilic structure and organosilicon structure enable the leveling agent to migrate more quickly to the surface of wet films, forming a monolayer on the film's surface. The high surface tension of the ionic liquid effectively increases the surface tension of the polyurethane coating, providing the driving force for leveling the high-viscosity wet film. This reduces the coating's leveling time, bringing it close to or less than the flow time. The resulting coating exhibits excellent leveling performance and produces no optical distortion.

[0078] It should be understood that the expression "one or more of" includes individually each of the items recited after the expression and various combinations of two or more of the recited items, unless otherwise apparent from the context and usage. The expression "and / or" in conjunction with three or more recited items should be understood to have the same meaning, unless otherwise apparent from the context.

[0079] The terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, e.g., not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0080] In this application, the term "and / or" describes the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0081] Optical leveling: A beam of light passes through without causing optical distortion. On an optically flat or curved surface, after application and before the coating has dried into a film, the coating gradually shrinks to its smallest area due to surface tension. A coating with good leveling is free of optical defects and light distortion. Leveling is difficult to discern visually and requires a slide projection for observation.

[0082] Distortion: refers to the degree of distortion of the image formed by the optical system of an object relative to the object itself. Optical distortion refers to the degree of deformation calculated based on optical theory.

[0083] Optical distortion: It is an important optical indicator of aviation transparent parts. It refers to the optical defect that causes distortion of the image of the observed object when observing the object through aviation plexiglass.

[0084] It should be understood that the order of steps or the order in which certain actions are performed are not important as long as the present invention remains operable. Additionally, two or more steps or actions may be performed simultaneously.

[0085] The use of any and all examples or exemplary language, such as "such as" or "including," herein is intended merely to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0086] In addition, the numerical ranges and parameters used to define the present invention are approximate values. The relevant numerical values ​​in the specific examples have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual testing methods. Therefore, unless otherwise expressly stated, all ranges, amounts, values, and percentages used in this disclosure should be understood to be modified by the word "about." As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specified value or range.

[0087] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0088] Some cases are described in the embodiments and comparative examples of the present invention, wherein the embodiments illustrate certain implementations of the present invention. However, this does not mean that the effects of the present invention can only be achieved in these cases.

[0089] In order to further illustrate the present invention, a leveling agent suitable for high optical components provided by the present invention, a preparation method thereof, and applications thereof are described in detail below with reference to examples.

[0090] Example 1

[0091] The preparation method of the above-mentioned optical leveling polyurethane protective coating comprises:

[0092] Step 1: Prepare a leveling agent. The raw materials, calculated by weight, include: 50.42% of Silok 8802F, 24.38% of 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.07% of concentrated sulfuric acid, and 25.13% of toluene. The above raw materials are placed in a stirred reaction vessel and the temperature is controlled at 85°C for 2-10 hours. During the reaction, nitrogen is purged and water is condensed to obtain a leveling agent.

[0093] Step 2: Applying a leveling agent to the polyurethane protective coating, the raw materials of which include, by weight: 28.67% of polycaprolactone diol (PCL210N), 2.25% of 1,2,4-butanetriol, 0.09% of catalyst dibutyltin dilaurate, 0.18% of the leveling agent of the present invention, 0.23% of antioxidant, 0.23% of ultraviolet absorber, 0.23% of light stabilizer, 27.01% of butyl acetate, 27.01% of N,N-dimethylformamide, and 14.10% of isophorone diisocyanate.

[0094] Step 3: Pour the mixture from step 2 and aliphatic diisocyanate into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical flow coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours. Figure 2 is the NMR comparison diagram of Example 1; Figure 2 1 H NMR spectrum analysis showed that the chemical signals of the hydrogen atoms at positions 5 and 7 of 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt shifted to the high field, confirming that the carboxyl group had undergone esterification reaction.

[0095] Figure 3 This is the nuclear magnetic integral diagram of the reaction results of Example 1, Figure 3 It can be seen that the conversion rate of the esterification reaction is 91%.

[0096] Example 2

[0097] Step 1: Prepare a leveling agent. The raw materials, calculated by weight, include: 50.42% of Silok 8802F, 24.38% of 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.07% of concentrated sulfuric acid, and 25.13% of toluene. The above raw materials are placed in a stirred reaction vessel and the temperature is controlled at 85°C for 2-10 hours. During the reaction, nitrogen is purged and water is condensed to obtain a leveling agent.

[0098] Step 2: 49.8% of Nobi 101 varnish A, 24.9% of Nobi 101 varnish B, 0.4% of the leveling agent of the present invention, and 24.9% of the diluent.

[0099] Step 3: Pour the mixture from step 2 into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical flow coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours.

[0100] Example 3

[0101] Step 1: Prepare a leveling agent. The raw materials, calculated by weight, include: 50.42% of Silok 8802F, 24.38% of 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.07% of concentrated sulfuric acid, and 25.13% of toluene. The above raw materials are placed in a stirred reaction vessel and the temperature is controlled at 85°C for 2-10 hours. During the reaction, nitrogen is purged and water is condensed to obtain a leveling agent.

[0102] Step 2: 49.8% of Nobin 102 varnish A, 24.9% of Nobin 102 varnish B, 0.4% of the leveling agent of the present invention, and 24.9% of Nobin standard diluent.

[0103] Step 3: Pour the mixture from step 2 into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical flow coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours.

[0104] Comparative Example 1

[0105] Step 1: 50% of Nobi 101 Clear Coat A, 25% of Nobi 101 Clear Coat B, and 25% of thinner.

[0106] Step 2: Pour the mixture from step 2 into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical spray coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours.

[0107] Comparative Example 2

[0108] Step 1: 50% of Nobi 102 Clear Coat A, 25% of Nobi 102 Clear Coat B, and 25% of thinner.

[0109] Step 2: Pour the mixture from step 2 into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical spray coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours.

[0110] Comparative Example 3

[0111] This comparative example provides a coating composition, which differs from Example 2 only in that the leveling agent is replaced with a structure of Formula 3; the composition comprises, by mass, 49.8 parts of Nobin 101 Varnish A, 24.9 parts of Nobin 101 Varnish B, 0.4 parts of the polymer provided in this example as a leveling agent (structure of Formula 3), and 24.9 parts of a diluent.

[0112] The preparation method of the coating composition comprises:

[0113] Pour NOBIN 101 Varnish A, NOBIN 101 Varnish B, a leveling agent, and a diluent into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to organic glass by vertical flow coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours to obtain a coating composition.

[0114]

[0115] Comparative Example 4

[0116] Step 1: Use single-end hydroxyl silicone to prepare a leveling agent. The raw materials include, by weight: 1.52% of Silok 88616, 18.89% of 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.06% of concentrated sulfuric acid, and 19.53% of toluene. The above raw materials are placed in a stirred reaction vessel and the temperature is controlled at 85°C for 2-10 hours. During the reaction, nitrogen is purged and water is condensed to obtain a product polymer.

[0117] Step 2: Apply the product of step 1 to a polyurethane protective coating, wherein the raw materials include, by weight: 28.67% of polycaprolactone diol (PCL210N), 2.25% of 1,2,4-butanetriol, 0.09% of catalyst dibutyltin dilaurate, 0.18% of the leveling agent of the present invention, 0.23% of antioxidant, 0.23% of ultraviolet absorber, 0.23% of light stabilizer, 27.01% of butyl acetate, 27.01% of N,N-dimethylformamide, and 14.10% of isophorone diisocyanate.

[0118] Step 3: Pour the mixture from step 2 and aliphatic diisocyanate into a stirred reactor, control the temperature at 21°C to react for 2 hours, let it stand for 30 minutes to remove bubbles, and apply the coating to the organic glass by vertical flow coating at 21°C. After leveling and surface drying for 2-6 hours, transfer the product to a forced air drying oven for curing at 70°C for 24 hours.

[0119] The coating compositions provided in Examples 1-4 and Comparative Examples 1-3 were subjected to performance tests using the following methods:

[0120] Light transmittance: GBT 2410-2008

[0121] Haze: GBT 2410-2008

[0122] Leveling status: Visual evaluation with 30° projection of a slide

[0123] Taber100 stroke haze increase after treatment: ASTM F735

[0124] The leveling effect of the coating prepared by the coating composition provided in Examples 1-3 and Comparative Examples 1-4 is as follows: Figure 4 and 5 As shown (the figure is a 30° slide projection photo, a is Example 1, b is Example 2, c is Example 3, d is Comparative Example 1, e is Comparative Example 2, f is Comparative Example 3, and g is Comparative Example 4).

[0125] The test results are shown in Table 1:

[0126] Table 1 Leveling state of the embodiment and the comparative example

[0127]

[0128]

[0129] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a leveling agent suitable for high optical parts, characterized in that: The steps include: The product is obtained by carrying out esterification reaction in the presence of mono- or di-terminal hydroxyl organic silicone resin, functional ionic liquid, catalyst and solvent.

2. The preparation method according to claim 1, characterized in that The double-terminated hydroxyl silicone resin is Silok8802F.

3. The preparation method according to claim 1, characterized in that The cation in the functional ionic liquid comprises one or more of a hydroxyl group, an amino group and a carboxyl group; and the functional ionic liquid is 1-carboxyethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt.

4. The preparation method according to claim 3, characterized in that The catalyst is concentrated sulfuric acid or tetrabutyl titanate; The solvent includes toluene or xylene.

5. The preparation method according to claim 1, characterized in that The molar ratio of the mono- or di-terminated hydroxyl organic silicone resin and the functional ionic liquid is 1:1; The mass of the solvent is 1% to 100% of the total mass of the mono- or di-terminated hydroxyl organic silicone resin, the functional ionic liquid, the catalyst and the solvent; The mass of the catalyst is 0.01% to 1% of the total mass of the mono- or di-terminated hydroxyl organic silicon resin, the functional ionic liquid, the catalyst and the solvent.

6. The preparation method according to claim 1, characterized in that The esterification reaction temperature is 70-100°C and the time is 2-10 hours; During the esterification reaction, nitrogen was purged and water was removed by condensation.

7. A leveling agent suitable for high optical parts, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 6.

8. An optical leveling polyurethane protective coating, characterized in that: The invention comprises a coating component A and a coating component B, wherein the coating component A comprises a polyol, a chain extender, a catalyst, a solvent, a leveling agent prepared by the preparation method according to any one of claims 1 to 7, and a light stabilizer; and the coating component B is an aliphatic diisocyanate or trimer.

9. The optical leveling polyurethane protective coating according to claim 8, characterized in that: The mass of the leveling agent is 0.1 to 0.5% of the mass percentage of the optical leveling polyurethane protective coating.

10. A method for preparing the optical leveling polyurethane protective coating according to claim 8 or 9, characterized in that: The steps include: Mix the coating component A and the coating component B, stir and react, filter, let stand to remove bubbles, apply the coating to the organic glass by vertical spray coating, and solidify after leveling and surface drying.

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