WO2023227107A1

WO2023227107A1 - Coating composition

Info

Publication number: WO2023227107A1
Application number: PCT/CN2023/096522
Authority: WO
Inventors: Qiangqiang Mao; Qiang Chen
Original assignee: Ppg Coatings (Tianjin) Co., Ltd.
Priority date: 2022-05-26
Filing date: 2023-05-26
Publication date: 2023-11-30
Also published as: TW202346494A; CN114836114A

Abstract

Provided is a coating composition, comprising a silicon-modified polyether resin, a silane prepolymer sol and inorganic oxide nanoparticles. Also provided is a coated substrate, comprising a substrate and the coating composition coated on at least part of the substrate. Further provided is a use of the coating composition in the formation of a single layer for providing anti-fingerprint property, high adhesion, and/or excellent matte effect to a glass substrate.

Description

COATING COMPOSITION

TECHNICAL FIELD

The present invention relates to the field of coatings, in particular to an anti-fingerprint coating for glass substrates.

BACKGROUND

Electronic products, such as, mobile phones, computers, and televisions become more and more indispensable in daily work and life. The electronic products, including glass surfaces such as touch screens and display panels, are easily stained by fingerprints due to frequent touching, which affect the appearance of the products. Moreover, to some customers, an electronic product with matte effect surface is more attractive.

At present, dual-layer coating systems are widely used in the market to coat the glass surface of electronic products, that is, a first layer producing a matte effect and a second layer coated on the first layer and providing an anti-fingerprint effect. Although the dual-layer coating system meets the requirements of performance and appearance, it is complicated to operate, time-consuming, and labor-consuming during application, leading to high cost. However, the anti-fingerprint effect of the dual-layer coating system basically comes from fluorine-containing components, which are difficult to be compatible with conventional solvents so that it is impossible to achieve both the matte effect and the anti-fingerprint effect in a single-layer coating system.

Thus, it would be desirable to develop a single-layer coating composition which can meet various requirements of performance and appearance at the same time for the application on glass substrate of an electronic product.

SUMMARY

The present inventor has done a lot of research and developed a coating composition which is suitable for application onto a glass substrate as a single layer, and has superior performance and appearance including anti-fingerprint property, high adhesion, and excellent matte effect, etc.

The present invention provides a coating composition, comprising a silicon-modified polyether resin, a silane prepolymer sol and inorganic oxide nanoparticles.

The present invention provides a coated substrate, comprising a substrate and the coating composition coated on at least part of the substrate.

The present invention further provides a use of the coating composition in the formation of a single layer for providing anti-fingerprint property, high adhesion, and/or excellent matte effect to a glass substrate.

The characteristics and advantages of the present invention will be particularly presented in the detailed description of the following embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Effects of fingerprints on glass substrate coated with double-layer coating compositions of AG203 and EC303 from PPG (a) or single-layer anti-fingerprint matte coating composition of the invention (b) .

DETAILED DESCRIPTION

In the present application, unless expressly stated otherwise, the use of a singular includes a plural and the use of a plural includes a singular. For example, even though “a” resin is mentioned herein, one or more resins can be used.

In the present application, the terms such as “comprise/comprising” , “contain/containing” and “include/including” are not intended to limit the present invention to exclude any variation or addition. Furthermore, even though the present invention has described the coating compositions, preparation methods and the like with “comprising” or similar terms, those coating compositions, preparation methods and the like can also be described as “consisting essentially of” or “consisting of” . In this case, “consisting essentially of” means that any additional component will not produce any substantive effect on the properties of the coating layer formed by the coating composition.

In the present application, unless expressly stated otherwise, the use of “or” means “and/or” , even though “and/or” can be expressly used in some cases. In addition, it is to be understood that any numerical range listed herein is intended to encompass all the sub-ranges included therein. For example, a range of “1 to 10” is intended to include all the sub-ranges between the listed minimum value of 1 and the listed maximum value of 10 (including the end values) , namely, all the sub-ranges with a minimum value of equal to or greater than 1 and a maximum value of equal to or less than 10.

Unless described in the examples or otherwise explicitly stated, it is to be understood that all numerical values representing the quantities of components or the like as used in the description and claims can vary in all substances as is modified with the term “about” . Thus, unless indicated to the contrary, the numerical parameters listed in the following description and the accompanying claims are all approximations, and can be varied depending upon the properties to be obtained by the present invention. At the least, and not to limit the application of the doctrine of equivalents to the scope of claims, each numerical parameter should at least be interpreted based on significant figures and ordinary rules of rounding.

Although the numerical ranges and parameters describing the broad scope of the present invention are approximations, the numerical values recorded in the particular examples should be reported as precisely as possible. However, any one value inherently has a certain error, which is an inevitable consequence of standard deviation found in its corresponding measurement method.

The coating composition according to the present invention may be a single-layer coating composition. As used herein, the term “single-layer” refers to a single coating layer, i.e., a coating layer formed by one single application. Herein, the film thickness of the single coating layer may be in the nanometer range, i.e., not greater than 1 μm.

The coating composition according to the present invention may be a single-component coating composition. The “single-component coating” refers to a single-package coating, which has advantages of ready-to-use, convenient storage and application.

The coating composition according to the present invention may be a thermoset coating composition, i.e., the coating composition irreversibly forms a coating film by curing, which cannot be molten upon reheating and cannot be dissolved in a solvent. Herein, the term “curing” means that at least some component (s) of the coating composition is/are polymerized and/or crosslinked, or dried to form a hardened coating film. The coating composition according to the present invention can be cured by heating.

The coating composition according to the present invention may be a non-crosslinking composition. That is, the coating composition does not comprise any crosslinking agent and will not undergo a crosslinking reaction between resins.

The coating composition according to the present invention may be a composition with low solid content. Suitably, the coating composition according to the present invention may have a solid content of not greater than 10 wt. %, e.g., 6-8 wt. %. Herein, the term “solid content” refers to a ratio of the residual mass of a coating composition after drying for cure to the mass of the coating composition prior to drying for cure.

The coating composition according to the present invention can form a matte coating. Herein, the term “matte” means that the cured coating can have a gloss at 60 degree angle of not greater than 40. Herein, the gloss value can be measured by commercially available gloss meter. Suitably, the coating formed by the cured coating composition according to the present invention can have a gloss at 60 degree angle of not greater than 30. The gloss value can be determined by reference to the ASTM D523-14 (2018) standard using a BYK Gardner BYK4586-Micro-Tri-Gloss.

The coating formed by the coating composition according to the present invention may have an anti-fingerprint property. Herein, the “anti-fingerprint property” refers to the ability of the coating surface to resist fingerprint and on which fingerprint can be easily wiped. The single coating formed by the coating composition according to the present invention can have an anti-fingerprint comparable to that of a dual-layer coating system of AG203 and EC303 from PPG, as shown in FIG. 1.

The coating formed by the coating composition according to the present invention may have good glass substrate adhesion. Herein, the “substrate adhesion” is measured by reference to the ASTM D3359 standard. Suitably, the coating composition according to the present invention can have a glass substrate adhesion of 4B or greater.

As used herein, the polyether resin refers to a polymer comprising an ether linkage. Herein, the term “polymer” refers to prepolymers, oligomers, as well as homopolymers and copolymers as well as mixtures thereof.

The silicon-modified polyether resin used in the coating composition according to the present invention refers to a polyether resin comprising a silane group and/or a siloxane group. The silane/siloxane group can be attached to the backbone of the polyether resin. Suitably, the silane/siloxane group can be attached to an end/ends of the backbone of the polyether resin. The silane group can comprise a silicon-alkyl linkage. The siloxane group can comprise a silicon-alkoxy linkage.

Suitably, the silicon-modified polyether resin can comprise a terminal group comprising at least one silicon-alkoxy linkage. For example, the silicon-modified polyether resin can comprise a terminal group comprising one silicon-alkoxy linkage and two silicon-alkyl linkages. For example, the silicon-modified polyether resin can comprise a terminal group comprising two silicon-alkoxy linkages and one silicon-alkyl linkage. For example, the silicon-modified polyether resin can comprise a terminal group comprising three silicon-alkoxy linkages.

The silicon-modified polyether resin can comprise an ester linkage and a carbamate linkage. Suitably, both the ester linkage and the carbamate linkage are attached to the backbone of the polyether resin.

The silicon-modified polyether resin can have a weight average molecular weight of at least 500 g/mol, suitably a weight average molecular weight of at least 1000 g/mol, such as a weight average molecular weight of at least 2000 g/mol. The weight average molecular weight (M_w) is measured by gel permeation chromatography using a suitable standard (e.g., a polystyrene standard) .

The silicon-modified polyether resin can comprise at least 0.1 wt. %, suitably at least 0.2 wt. %, such as at least 0.3 wt. %, and/or at most 4.0 wt. %, suitably at most 3.0 wt. %, e.g., at most about 2.0 wt. %based on the total weight of the coating composition. The silicon-modified polyether resin can comprise 0.1-4.0 wt. %, suitably 0.2-3.0 wt. %, such as 0.3-2.0 wt. %, or a range of any combination of the above endpoints, based on the total weight of the coating composition.

The silane prepolymer sol used in the coating composition according to the present invention may be a short chain silica sol. Herein, the term “prepolymer” can be used interchangeably with polymer. Herein, the term “sol” refers to a system in which solid particles are suspended in a liquid. Herein, the “short chain silica sol” refers a sol in which the solid particles have a particle size of no more than 1000 nm, determined by BET method. Suitably, the solid particles have a particle size of 1-100 nm, determined by BET method. The short chain silica sol can be formed by hydrolysis and polycondensation of ethyl orthosilicate under acidic condition (pH<4) . Suitably, the silane prepolymer sol can be prepared from a mixture including ethyl orthosilicate and an alcohol. Suitably, the alcohol comprises ethanol and/or iso-propanol. For example, the silane prepolymer sol can be prepared by dispersing ethyl orthosilicate uniformly in ethanol at a mass ratio of ethyl orthosilicate to ethanol of about 1: 1-3, e.g., 1: 1.5-2.5; followed by adding an aqueous nitric acid; and then reacting at room temperature (about 23℃) for 1-2 hours.

Suitably, the ethyl orthosilicate for preparing the silane prepolymer sol has a SiO₂ content of at least about 25 wt. %, e.g., about 28-30 wt. %.

The silane prepolymer sol can comprise at least about 40 wt. %, suitably at least about 45 wt. %, e.g., at least 50 wt. %, and/or at most about 80 wt. %, suitably at most about 70 wt.%, e.g., at most 60 wt. %, based on the total weight of the coating composition. The silane prepolymer sol can comprise 40-80 wt. %, suitably 45-70 wt. %, such as 50-60 wt. %, or a range of any combination of the above endpoints, based on the total weight of the coating composition.

The above-described silicone-modified polyether resin and the silane prepolymer sol have good adhesion therebetween and will form some chemical bonds after curing. Moreover, the above-described silicon-modified polyether resin and the silane prepolymer sol form good cooperation therebetween, providing superior anti-fingerprint performance and adhesion to a substrate (such as, glass) at the same time.

Suitably, the weight ratio of the silicon-modified polyether resin to the silane prepolymer sol can be 1: 20-140, such as 1: 30-130.

The inorganic oxide nanoparticles used in the coating composition according to the present invention refer to particles having nano-scaled particle size (i.e., less than 1000 nm) and comprising inorganic oxide as the primary component. The “primary component” means that the particles comprise at least 70 wt. %, such as at least 80 wt. %, suitably at least 90 wt. %, or even at least 96 wt. %of inorganic oxide based on the total weight of the particles. Suitably, the inorganic oxide nanoparticles have an average particle size of not greater than 100 nm, suitably an average particle size of not greater than 80 nm, such as an average particle size of not greater than 50 nm. The “average particle size” can be measured by BET method.

Suitably, the inorganic oxide nanoparticles can comprise silica particles, alumina particles and/or titania particles.

Suitably, the silica particles can be in a form of silica sol dispersed in an alcohol. Suitably, the alcohol can be iso-propanol. The silica sol can comprise 20-40 wt. %of the silica particles, based on the total weight thereof. The silica particles can have an average particle size of 20-50 nm.

Suitably, the alumina particles can be in a form of alumina sol dispersed in an alcohol. Suitably, the alcohol can be iso-propanol. The alumina sol can comprise 10-20 wt. %of the alumina particles, based on the total weight thereof. The alumina particles can have an average particle size of 20-30 nm.

The inorganic oxide nanoparticles can comprise 0.5 wt. %, suitably at least 1 wt. %, such as at least 2 wt. %, and/or at most 14 wt. %, suitably at most 12 wt. %, e.g., at most about 10 wt. %, based on the total weight of the coating composition. The inorganic oxide nanoparticles can comprise 0.5-14 wt. %, suitably 1-12 wt. %, such as 2-10 wt. %, or a range of any combination of the above endpoints based on the total weight of the coating composition.

In the present invention, specific inorganic oxide nanoparticles can be highly compatible with the above-described silicon-modified polyether resin, imparting a matte effect to the coating layer, while keeping the dry film surface smooth, and avoiding the problems of roughness and particle shedding. Moreover, the inorganic oxide nanoparticles do not adversely affect the anti-fingerprint performance and adhesion of the coating layer.

Suitably, the weight ratio of the silicon-modified polyether resin to the inorganic oxide nanoparticles can be 1: 0.5-10, such as 1: 1-8, e.g., 1: 1.5-6.

The coating composition according to the present invention can further comprise 20-60 wt. %of a solvent based on the total weight of the coating composition. Suitable solvent comprises, but is not limited to, benzene, toluene, xylene, methyl acetate, ethyl acetate, n-propyl acetate, ethanol, and mixtures thereof. Suitably, the solvent comprises ethanol.

The coating composition according to the present invention can further comprise one or more other additives including, but not limited to, a silane coupling agent assisting in the interaction between the coating layer and the substrate; a film-forming aid improving the coalescence and storage stability of the composition; a dispersing agent facilitating the compatibility of components in the coating composition; a foam suppressor and a defoaming agent inhibiting the bubble formation and allowing the generated bubbles to escape or break during the production; a leveling agent improving the coating workability to provide a smooth coating; a perfume providing the coating with a pleasing odor; a rheology modifier improving the flowability and levelling property and reducing the defects; a preservative protecting the coating layer from mildew; a pH regulator controlling the pH and stabilizing the coating; a wax improving the scratch resistance and the touch; a thickening agent increasing the coating viscosity and improving the wet film thickness and protecting the coating from sedimentation and layer separation; and so on. In use, the type and amount of other additives are determined in accordance with the desired performance of the coating composition.

The coating composition according to the present invention can be substantially free of other surfactants. Herein, the “other surfactants” refers to components capable of affecting the surface energy of the coating composition in addition to the silicon-modified polyether resin, the silane prepolymer sol, and the inorganic oxide nanoparticles. By “substantially free of” is meant that the amount present in the coating composition is less than 1000 ppm based on the total weight of the coating composition.

The coating composition according to the present invention can be substantially free of fluorine. By “substantially free of” is meant that the amount present in the coating composition is less than 1000 ppm based on the total weight of the coating composition.

The coating composition according to the present invention can consist essentially of the silicon-modified polyether resin, the silane prepolymer sol, the inorganic oxide nanoparticles and a solvent. In this case, by “consist essentially of” is meant that any additional component will not substantively affect the properties of the coating, e.g., gloss, anti-fingerprint effect and adhesion to glass substrate of the formed coating layer. In other words, the gloss, the anti-fingerprint effect and the adhesion to glass substrate are not obtained by adjustment of added amount of the additional components into the coating composition according to the present invention. In the present invention, the silicone-modified polyether resin, the silane prepolymer sol and the inorganic oxide nanoparticles are selected to generate a synergistic effect so that the coating composition can generate a strong attachment (e.g., an attachment of Si-OH) to the surface of substrate (such as, glass substrate) after coating and curing, thereby providing good adhesion to the substrate and an anti-fingerprint property and a matte effect.

The coating composition according to the present invention can be prepared by a method comprising:

adding a silane prepolymer sol, silica particles and a silicon-modified polyether resin in sequence, stirring the mixture at room temperature so that the components are uniformly dispersed to a state of transparent and clear solution. Suitably, the stirring is carried out at 300-500 rpm for 0.5 hours. Then, the mixture is diluted with a solvent.

The silane prepolymer sol can be prepared by:

dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid, and reacting at room temperature for 1.5 hours.

Also disclosed is a coated substrate, comprising a substrate and the coating composition coated on at least part of the substrate. The coating composition according to the present invention can be applied on to the substrate by a well-established conventional technology, such as, brush coating, spraying, and dipping.

The coating composition developed by the present inventor can form a coating layer with nano-scaled thickness, that is, the coating layer formed from the coating composition has a thickness of not greater than 1 micron. Suitably, the coating layer formed from the coating composition according to the present invention can have a dry film thickness of 100-200 nm. Thus, the present invention has made obvious progress in comparison with current commercially available coatings with micron-scaled thickness. The coating layer with nano-scaled thickness formed from the single-layer coating composition in accordance with the present invention avoids phenomena such as poor spraying, orange peel, and shrinkage cavity, and provides good leveling property. The coating composition according to the present invention can be thermally cured after application onto the substrate. Suitably, the coating composition according to the present invention can be baked at 150-180℃ for 60-90 minutes.

The coating composition according to the present invention is suitable for application onto numerous substrates, such as, glass substrates. The coating composition according to the present invention can be applied onto substrates of electronic products. The glass substrates can comprise, but are not limited to, quartz glass, silicate glass, soda-lime glass, high-temperature glass, high pressure-resistant glass, UV resistant glass, and/or explosion-proof glass, etc. The glass substrate can be subject to a pretreatment, such as, plasma treatment, to activate the substrate surface.

The coating composition according to the present invention can also be used to coat an anodic aluminum substrate.

The coating composition according to the present invention can form a single coating layer on the glass substrate. Namely, there is only the one coating layer formed by the coating composition of the present invention on the glass substrate. The coating composition can be used for providing anti-fingerprint property, high adhesion, and/or excellent matte effect even when applied as a single layer to a glass substrate. The single layer may have a thickness of not greater than 1 micron.

The coated substrate can comprise a coating layer with a dry film thickness of not greater than 1 micron. The surface of the coated substrate may have a gloss at 60 degree angle of not greater than 40. The surface of the coated substrate can be a coating layer formed by the coating composition of the present invention. The surface of the coated substrate further has a good anti-fingerprint effect. As shown in FIG. 1, the single coating layer formed by the coating composition according to the present invention can have a matte effect and an anti-fingerprint effect comparable to that of a dual-layer coating system, as shown in FIG. 1. The coating layer of the coated substrate is substantially free of fluorine. By “substantially free of” is meant that the amount present in the coating layer is less than 1000 ppm.

In another aspect, the present invention further provides use of the coating composition for coating a substrate. The substrate may comprise a glass substrate. The substrate can be a substrate of electronic product.

EXAMPLES

The following examples are provided to further illustrate the present invention, but should not be construed to limit the present invention to the details of the examples. All parts and percentages in the following examples are by weight, unless otherwise stated.

Example 1. Preparation of Coating Composition 1

Coating composition 1 was prepared in accordance with the components and amounts as listed in Table 1 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence silica sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 1. Coating Composition 1

Example 2. Preparation of Coating Composition 2

Coating composition 2 was prepared in accordance with the components and amounts as listed in Table 2 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence silica sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 2. Coating Composition 2

Example 3. Preparation of Coating Composition 3

Coating composition 3 was prepared in accordance with the components and amounts as listed in Table 3 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence silica sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 3. Coating Composition 3

Example 4. Preparation of Coating Composition 4

Coating composition 4 was prepared in accordance with the components and amounts as listed in Table 4 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence silica sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 4. Coating Composition 4

Example 5. Preparation of Coating Composition 5

Coating composition 5 was prepared in accordance with the components and amounts as listed in Table 5 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence alumina sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 5. Coating Composition 5

Example 6. Preparation of Coating Composition 6

Coating composition 6 was prepared in line with the components and amounts as listed in Table 6 below: uniformly dispersing ethyl orthosilicate in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding in sequence alumina sol and silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 6. Coating Composition 6

Comparative Example 1: Preparation of Comparative Coating Composition 1

Comparative coating composition 1 was prepared in accordance with the components and amounts as listed in Table 7 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding silicon-modified polyether resin, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 7. Comparative Coating Composition 1

Comparative Example 2: Preparation of Comparative Coating Composition 2

Comparative coating composition 2 was prepared in accordance with the components and amounts as listed in Table 8 below: dispersing ethyl orthosilicate uniformly in an amount of ethanol (with a mass ratio of ethyl orthosilicate to ethanol of about 1: 2) , following by adding an aqueous nitric acid solution, and reacting at room temperature for 1.5 hours; adding silica sol, and stirring at room temperature at 300-500 rpm for 0.5 hours; and finally diluting the mixture with ethanol.

Table 8. Comparative Coating Composition 2

Test for Performance:

Coating compositions 1-6 and Comparative coating compositions 1-2 were sprayed onto the surface of a glass substrate via air spraying to a thickness of less than 1 μm, followed by baking at 150-180℃ for 60-90 minutes. Then, the substrates comprising coating layers formed from Coating compositions 1-6 and Comparative coating compositions 1-2 were subject to the following tests, respectively, and the results are listed in Table 9 below.

1. Gloss

At room temperature, the formed coating layer was subject to gloss test. The test was carried out by reference to the ASTM D523-14 (2018) standard using a BYK Gardner BYK4586-Micro-Tri-Gloss.

2. Anti-Fingerprint Effect

The substrate surface was observed after pressing by fingers, and then rated for its anti-fingerprint effect as follows:

1-2: Fingerprint impressions were clearly shiny after pressed on the surface; the whole fingermarks were black and glossy on the substrate surface upon wiping with finger, and can hardly be wiped off; Rate 2 was slightly better than Rate 1;

3:Fingerprint impressions were not shiny after pressed on the surface; the fingermarks were slightly black upon wiping with finger, and can substantially wiped off;

4-5: Fingerprint impressions were not clearly visible after pressed on the surface, can be easily removed by wiping with finger, and showed substantially the same color as other sites of the substrate surface; Rate 4 was slightly poorer than Rate 5.

3. Adhesion

At room temperature, the coating layer was subject to adhesion test. The test steps were as follows:

Referring to ASTM D3359: Cross-Cut Tape Test, using a 3M610 Adhesive Tape;

(1) Allowing the edge angle of blade between 15 and 30 degrees;

(2) Cutting the film every 1 mm (atotal of 11 cuts) for those with film thickness within 50 μm; and every 2 mm (atotal 6 cuts) for those with film thickness between 50 μm and 125 μm;

(3) Removing flocks with a soft brush and visually examining the surface of the plate; polishing with a very fine oilstone if there were any bumps or sharp metallic objects, and marking; and then re-cutting vertically at the initial position;

(4) Taking an adhesive tape with a length of 75mm (3 in) and a width of 25 mm (1 in) , covering the grid with the central region of the tape, and then flattening the tape with an eraser at the back end of pencil to ensure a full contact; pulling the tail end of the tape within 90 ± 30sec, and quickly pulling it back at around 180 degrees at 0.6-1.0 m/s. Each plate was tested at two positions.

The rating criteria are as follows:

5B: Cut edges are fully smooth, and there is no peeling at the edges of grids;

4B: There are small peelings at the intersects of cuts, and actual damage is less than or equal to 5%in the grids area;

3B: There are peelings at the edges or intersects of cuts, and the peeled area is greater than 5%and less than or equal to 15%;

2B: There are partial or large peelings along the edges of cuts, or whole peelings in some grids, and the peeled area is greater than 15%and less than or equal to 35%;

1B: There are large peelings at the edges of cuts or partial or whole peelings in some grids, and the peeled area is greater than 35%and less than or equal to 65%; and

0B: There are pieces of paints peeling at the edges of and intersects of cuts, and the total peeled area is greater than 65%.

Table 9. Test Results of Gloss, Anti-Fingerprint Effect and Adhesion

From the above, it can be seen that the coating composition according to the present invention has superior matte effect and anti-fingerprint effect and good adhesion to glass substrate, and its performance can be comparable with the current dual-layer coating anti-fingerprint product, as can be shown in FIG. 1. Moreover, the coating composition of the present invention is a single-layer coating product, which has advantages of cost savings and high application efficiency. At the same time, the coating composition according to the present invention meets the requirements of other mechanical performance and appearance of coatings for an electronic product.

Although particular aspects of the present invention have been illustrated and described, it is obvious to persons skilled in the art that many other variations and modifications can be made without departing the spirit and scope of the present invention. Thus, the accompanying claims are intended to encompass all of these variations and modifications falling within the scope of the present invention.

Claims

A coating composition, comprising a silicone-modified polyether resin, a silane prepolymer sol and inorganic oxide nanoparticles.
The coating composition of claim 1, wherein the coating composition is a one-component coating composition.
The coating composition of claim 1 or 2, wherein the weight ratio of the silicon-modified polyether resin to the silane prepolymer sol is 1: 20-140.
The coating composition of any one of claims 1-3, wherein the weight ratio of the silicon-modified polyether resin to the inorganic oxide nanoparticles is 1: 0.5-10.
The coating composition of any one of claims 1-4, wherein the silicon-modified polyether resin comprises an ester linkage and a carbamate linkage.
The coating composition of any one of claims 1-5, wherein the silicon-modified polyether resin comprises a terminal group, the terminal group comprises a silicon-alkyl linkage and/or a silicon-alkoxy linkage.
The coating composition of claim 6, wherein the terminal group comprises at least one silicon-alkoxy linkage.
The coating composition of any one of claims 1-7, wherein the silicon-modified polyether resin has a weight average molecular weight of at least 500 g/mol.
The coating composition of any one of claims 1-8, wherein the silane prepolymer sol comprises a short chain silica sol.
The coating composition of any one of claims 1-9, wherein the silane prepolymer sol is prepared from a mixture comprising ethyl orthosilicate and an alcohol, wherein the ethyl orthosilicate has a SiO₂ content of at least 25 wt. %.
The coating composition of any one of claims 1-10, wherein the inorganic oxide nanoparticles have an average particle size of not greater than 100 nm.
The coating composition of any one of claims 1-11, wherein the inorganic oxide nanoparticles comprise silica particles, alumina particles and/or titania particles.
The coating composition of claim 12, wherein the silica particles are provided in a form of silica sol dispersed in an alcohol, wherein the silica sol comprises 20-40 wt. %of silica particles based on the weight thereof, and the silica particles have an average particle size of 20-50 nm.
The coating composition of claim 12 or 13, wherein the alumina particles are provided in a form of alumina sol dispersed in an alcohol, wherein the alumina sol comprises 10-20 wt. %of alumina particles based on the weight thereof, and the alumina particles have an average particle size of 20-30 nm.
The coating composition of any one of claims 1-14, wherein the coating composition is substantially free of fluorine.
The coating composition of any one of claims 1-15, wherein the coating composition is a single-layer coating composition.
The coating composition of any one of claims 1-16, wherein the coating composition forms a nano-scaled coating.
The coating composition of any one of claims 1-17, wherein the coating composition forms a coating layer with a dry film thickness of not greater than 1 micron.
The coating composition of any one of claims 1-18, wherein the coating composition has a gloss at 60 degree angle of not greater than 40.
The coating composition of any one of claims 1-19, wherein the coating composition is used for coating a glass substrate.
A coated substrate, comprising a substrate and the coating composition of any one of claims 1-20 coated on at least part of the substrate.
The coated substrate of claim 21, wherein the substrate comprises glass.
The coated substrate of claim 21 or 22, wherein the substrate comprises a part of an electronic product.
The coated substrate of any one of claims 21-23, wherein the coating of the substrate has a dry film thickness of not greater than 1 micron.
The coated substrate of any one of claims 21-24, wherein the coating of the substrate has a gloss at 60 degree angle of not greater than 40.
The coated substrate of any one of claims 21-24, wherein the coating of the substrate is substantially free of fluorine.
Use of the coating composition of any one of claims 1-20 in the formation of a single layer for providing anti-fingerprint property, high adhesion, and/or excellent matte effect to a glass substrate.