JPH01141959A - Antifogging coating composition - Google Patents

Abstract

PURPOSE:To obtain a coating composition which can give a film having antifogging performance of excellent durability, abrasion resistance, flexibility, transparency and dyeability, by mixing two specified organosilicon compounds with a polycarboxylic acid and a curing agent. CONSTITUTION:This coating composition comprises the following components A-D and components A and B are each present in the form of a hydrolyzate: (A) is an organosilicon compound having an epoxy group-containing nonhydrolyzable organic group and at least two hydrolyzable groups introduced thereinto, (B) is 30-150pts.wt., per 100pts.wt. component A, at least one organosilicon compound having an ethylene oxide polymer unit introduced thereinto of formula I (wherein R<1> is a 1-4C alkyl group or an epoxy group- containing organic group, R<2> is a 1-4C alkyl group, and n is an integer of 3-30) or formula II (wherein R<1> and R<2> are each a 1-4C alkyl group and n is an integer of 3-30), (C) is 0.1-1 equivalent (in terms of carboxylic acid) per equivalent of the epoxy groups in components A and B, at least one member selected from an unsaturated or saturated polycarboxylic acid or its anhydride and 0.3-5.0pts.wt., per 100pts.wt. component A, curing agent (D).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides an anti-fog coating composition having excellent durability, anti-fog performance, abrasion resistance, flexibility, transparency, and dyeability. Regarding.

<Prior art> In recent years, transparent materials such as transparent plastics and inorganic glasses have been used to make use of their properties to produce architectural, vehicle or aircraft window glass, greenhouse glass or film, mirrors, optical lenses, eyeglass lenses, etc. It is widely used in however,
These transparent materials can be Condensation forms on the surface of the article, causing the inconvenience of clouding the surface and loss of transparency. Furthermore, in the case of plastic materials, there are problems in that the surface is easily scratched and has poor abrasion resistance, and transparency is easily reduced due to scratches.

Therefore, there has been a desire to solve these problems, and various attempts have been made to provide anti-fog performance and abrasion resistance, and although a number of proposals have been made, none have yet been found that are fully satisfactory. Not yet. For example, methods for imparting antifogging properties include surfactants, glycerin, and polyalkylene glycols for the purpose of making the surface hydrophilic and improving water wettability.

A method of applying a hydrophilic substance such as polyethyleneimine has been proposed. However, although these methods can temporarily impart antifogging performance, the antifogging performance deteriorates over time due to the outflow of the antifogging agent and tends to disappear.

In addition, the method of applying wood-loving polymers such as polyvinyl alcohol and polyhydroxyalkyl methacrylate is
There is a problem in that the abrasion resistance of the coating film is insufficient and it is easily scratched especially when moisture is absorbed.

On the other hand, as a method of hardening the surface of a plastic base material and making it less likely to be scratched, a coating with a melamine or silicone thermosetting paint, or an ultraviolet curing acrylic paint is used. Although these are effective in increasing the surface hardness of plastic substrates, they cannot impart antifogging performance.

Further, a silicone coating composition containing an epoxy group that imparts wear resistance and dyeability to the surface of a plastic substrate is proposed in Japanese Patent Publication No. 57-42665, but the coating composition is Anti-fog performance cannot be imparted to the surface of the plastic base material.

In order to solve these problems, the present applicant has proposed a coating composition comprising an organosilicon compound containing an epoxy group and polyethylene glycol (see Japanese Patent Laid-Open No. 62-201974).

<Problems to be Solved by the Invention> Although a coating film formed on a substrate using a coating composition consisting of an organosilicon compound containing an epoxy group and polyethylene glycol has excellent abrasion resistance,
Durability of anti-fog performance is insufficient (retention period is short)
When a cycle test is performed at high and low temperatures, the polyethylene glycol in the coating composition precipitates, causing problems such as the coating surface becoming white and cloudy and the anti-fog performance decreasing. I understand.

<Means for Solving the Problems> Therefore, the inventors of the present invention have made extensive efforts in development to solve these problems, and as a result, have achieved the following highly durable anti-fog performance and abrasion resistance. Flexible.

The inventors have come up with a coating composition that provides a coating film with transparency and dyeability. That is, the present invention provides (A) an organosilicon compound into which a non-hydrolyzable organic group having an epoxy group and at least two hydrolyzable groups have been introduced, (8) the general formula %) (However, R1 is an alkyl group having 1 to 4 carbon atoms or an organic group having an epoxy group, R2 is an alkyl group having 1 to 4 carbon atoms, and n is an integer of 3 to 30.) The introduced organosilicon compound and the general formula (where nl, R2 is an alkyl group having 1 to 4 carbon atoms, n
is an integer from 3 to 30); and (C) unsaturated or saturated polycarboxylic acids, or at least some of their acid anhydrides. Components (A) and (B) are present as hydrolysis reaction products.

Specific Explanation of Means for Solving> Hereinafter, means for solving the above problems will be explained in detail. Here, "1 part" indicating a compounding unit means "part by weight" unless otherwise specified.

(1) Component (^) of the present invention, that is, an organosilicon compound into which a non-hydrolyzable organic group having an epoxy group and at least two hydrolyzable organic groups are introduced, is generally prepared by silane coupling. It is called a carbon functional silane or a carbon functional silane, and among these, it has an epoxy group as an organic functional group. This component is the main component of the film-forming element of this coating composition, and it causes a condensation reaction between hydrolyzed silanol groups and epoxy groups.
The curing reaction with the acid or acid anhydride as component (C) provides a highly hard cured coating film having a crosslinked structure with a high degree of polymerization and excellent wear resistance.

The non-hydrolyzable organic group having an epoxy group in this component is:
Examples include glycidoxyalkyl group and epoxycyclohexylalkyl group. In addition, as a hydrolyzable group,
Halogen 9 acyloxy group.

Examples include an alkoxy group, an alkoxyalkoxy group, an amino group, etc., but an alkoxy group or an alkoxyalkoxy group is particularly preferable, since it is not preferable that the free product after hydrolysis has high reactivity with an epoxy group. Specific examples of these include: β-glycidoxyethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane δ-glycidoxybutyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycid Xypropyltriethoxysilane δ-glycidoxybutyltriethoxysilane, γ-glycidoxypropyltris(methoxyethoxy)silane, β-glycidoxyethyl(methyl)dimethoxysilane, γ-glycidoxypropyl(methyl) Dimethoxysilane, γ-glycidoxypropyl(vinyl)dimethoxysilane, γ-glycidoxypropyl(methyl)jethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4 -Epoxycyclohexyl)ethyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyl(methyl)jethoxysilane, [2-(3,4-epoxy-4-methylcyclohexyl)propylcomethyljethoxysilane, etc. can be mentioned.

These compounds can be used not only alone, but also in a mixture of two or more types.

These organosilicon compounds are used after being hydrolyzed. Hydrolysis is performed at room temperature of 0.5~
This is carried out by adding 1.5 equimole of water, preferably a dilute aqueous acidic solution of 0.1 to 0.001 normal (N) such as hydrochloric acid, sulfuric acid, perchloric acid, etc. It is also possible to perform hydrolysis after mixing the organosilicon compound with a solvent. As the solvent, alcohol (ex, methanol, IPA), ketone (ex, MI BK), ester, ether, glycol ether (ex, Cellosolve), cyclic ether, etc. can be used as appropriate. Furthermore, if hydrolysis and initial condensation are to be carried out in a short time depending on the purpose, 50 to 8
The hydrolysis reaction can also be carried out in a state heated to 0°C.

(2) Component (B) of the present invention is: ■ General formula % formula %) (However, R1 is an organic group having an alkyl group having 1 to 4 carbon atoms or an epoxy group, R2 is an alkyl group having 1 to 4 carbon atoms, n is an integer of 3 to 30);
is an integer from 3 to 30).

In the above, the organosilicon compound in which three hydrolyzable groups have been introduced into the silicon present only at one end of the chain shown in formula (■) can be synthesized by various known methods. . Here, if one or two hydrolyzable groups are introduced into silicon, the crosslinking density of the cured coating film formed from the coating composition will be coarse, and the abrasion resistance will be reduced, which is not preferable.

An organosilicon compound in which two hydrolyzable groups are introduced into each silicon at both ends of a chain represented by the formula (1) can be synthesized by various known methods (Japanese Patent Publication No. 58-198-1). (See Publication No. 41291, etc.). If three hydrolyzable groups are introduced into the silicon at both ends, the reactivity of the organosilicon compound will be too high and the coating composition will begin to cure in a short period of time, causing problems in the stability of the coating composition. Occur. Furthermore, if only one hydrolyzable group is introduced into the silicon at both ends, problems tend to occur in the abrasion resistance of the cured coating film formed from the coating composition.

This component (8) is added to the coating composition to impart antifogging performance, and is the component (A) of the component (B).
The blending ratio for component (A) is preferably 30 to 150 parts per 100 parts of component (A); if it is less than this, sufficient antifogging performance cannot be obtained, and if it is more than this, abrasion resistance is insufficient.

(3) Component (C) of the present invention, that is, at least one unsaturated or saturated polyhydric carboxylic acid or its acid anhydride, reacts with the epoxy group of component (A) to increase the crosslinking density,
It provides a highly hard coating film with excellent abrasion resistance, and at the same time, it also provides dyeing properties and other functions to the coating film.

All of the acid anhydrides listed as curing agents for epoxy resins can be used as component (C). In addition, similar carboxylic acids (eg, phthalic acid for phthalic anhydride) can also be used. In addition, succinic acid, glutaric acid, adipic acid, malic acid, citric acid, tartaric acid, itaconic acid, which is not often used as a curing agent for epoxy resins,
Citraconic acid, maleic acid, fumaric acid, etc. and their acid anhydrides, as well as pyromellitic dianhydride, benzophenonetetracarboxylic dianhydride, etc., can be used by dissolving them in a solvent, making it effective because the optimum blending ratio can be created. It becomes a component.

The blending ratio of component (C) is 0.1 to 1.0 as carboxylic acid to the epoxy group in component (^) and (B).
Equivalent. If it is less than 0.1 equivalent, the effect of adding component (C) will not be apparent, and if it is more than 1.0 equivalent, free carboxyl groups will remain, which tends to cause problems in adhesion and water resistance.

(4) Component (D) of the present invention, that is, a curing agent; D-1)
Dicyandiamide, D-2) Aluminum trialkoxide or an aluminum chelate compound obtained by substituting its alkoxide with β-diketone or β-ketoester, 0-3) Imidazole or all or one of its 1, 2, 4° 5-positions. The part is an alkyl group.

It is a compound selected from the group consisting of substituted imidazoles substituted with an aryl group, a hydroxyalkyl group, an alkoxyalkyl group, a cyanoalkyl group, etc.

D-2) Specific examples of compounds include: aluminum isopropoxide, aluminum isobutoxide, aluminum-Sec-butoxide, aluminum di(isopropoxide) methyl acetoacetate, aluminum di(Sec-butoxide) ethyl acetoacetate, aluminum bis (ethyl acetoacetate) acetylacetonate, aluminum ethyl acetoacetate bis(acetylacetonate), aluminum acetylacetonate, etc. Further, specific examples of the substituted imidazole in D-3) include 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-isopropylimidazole, 2-phenylimidazole, 1-benzyl-2- Methylimidazole, 1-cyanoethylimidazole, ! -cyanoethyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-cyanoethyl-2-phenyl-4,5-bis(cyanoethoxymethyl)imidazole, and the like. Two or more of these compounds within the same group may be used in combination. Although the optimum amount of these additives differs depending on each component, it is generally 0.3 to 5.0 parts per 100 parts of component (A).

In addition to the above-mentioned essential components, the composition of the present invention can also contain solvents, additives, etc. in order to improve its performance as a paint.

As the solvent, those exemplified above can be used as appropriate. Further, as additives, silicone surfactants, fluorine surfactants, etc. can be used for the purpose of improving surface smoothness, that is, as leveling agents. Furthermore, it is also possible to add an ultraviolet absorber to block ultraviolet rays or to prevent deterioration caused by ultraviolet rays at the interface between the base material and the coating film. In addition, the composition of the present invention may contain dyes within a range that does not impair transparency.
It is also possible to color the coating film by adding pigments, and the antifogging coating composition of the present invention can be applied to various substrates, and is applied to the substrate and cured by heating. It is used by forming a film.

In this case, there are no particular restrictions on the base material as long as it does not impair the characteristics of the present invention, but in general, base materials that can effectively exhibit the characteristics include transparent plastic, inorganic glass, transparent ceramic, metal, etc. There is. Examples of transparent plastic materials include polycarbonate, polymethyl methacrylate, polydiethylene glycol bisallyl carbonate (rCR-39), cellulose propinate, polyvinyl chloride, polystyrene, and the like.

Practical examples include various lenses, goggles, and window glasses made of transparent plastic and inorganic glass.

The present invention is preferably used for glass and films for greenhouses, cover glasses for various instruments, etc.

As a method for applying the composition of the present invention to a substrate, commonly known methods such as brush coating, spray coating, dipping, spin coating, flow coach ink, etc. can be used.

Further, in order to improve the adhesion to the base material, it is also possible to pre-treat the base material by various types of brimer treatment, activated gas treatment, corona treatment, or chemical treatment with acids, bases, etc.

<Effects of the Invention> As is clear from the Examples and Comparative Examples described below, the coating composition of the present invention can be used to coat transparent plastics, inorganic glass, etc. with coating films that exhibit good antifogging properties and abrasion resistance over a long period of time. It can be obtained by coating and curing on a base material.

<Examples> The present invention will be explained in more detail below using examples. Comparative examples conducted for the purpose of confirming the curing of the examples are also described.

(1) The coating compositions of each Example and Comparative Example were prepared as follows. Note that each component and its usage amount are shown in Table 1.

Take both components (A) and (B) to a beaker, add an aqueous hydrochloric acid solution while stirring, stir for 30 minutes, and then leave at room temperature for 2 hours.
Leave it for 4 hours. In the thus obtained prepared solution, component (C),
Component (D) and a solvent were added and stirred to form a homogeneous solution, and then a silicone-based interfacial lubricant was added as a leveling agent to prepare a coating composition.

In addition, in Example 3 and Comparative Example 2, the (B) component was (A)
The components were added in the latter step, not in the earlier step of hydrolyzing the components, and in Example 4, Tol and B-3 were added separately in the earlier and later steps, respectively.

In addition, the compounds with the respective symbols indicating the components (^) and (B) in Table 1 were the following compound names or indicated formulas.

(8) Components: A1...γ-glycidoxypropyltrimethoxysilane, A2...β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, A3...γ-glycidoxypropyl(methyl ) dimethoxysilane, (B) component: B-1... (:, HsO(C)lac)Izol m (Ch)3
sI (OCIh) s8-2...B-3... (2) Formation of a cured coating film on a plastic substrate using each of the coating compositions prepared above was performed as follows.

The substrates of Examples 1 to 5 and Comparative Examples 1 to 4 were made of CR-39, which had been immersed in a 10% caustic soda aqueous solution heated to 50°C for 3 minutes, thoroughly washed with water, and then completely wiped of moisture. A lens (70 mmφ) was used.

The above substrate was immersed in each coating composition and coated at a pulling rate of 10 cm/min, followed by heat treatment under the conditions shown in Table 2 to form a cured coating film.

In Examples 3-1 to 3-5, the base materials were those shown in Table 3, the coating composition used was that of Example 3, and the curing conditions for the coating film were as shown. did. The coating conditions are the same as above.

(3) Next, physical property tests described separately were conducted on each of the cured coating films formed as described above.

The test results are shown in Tables 2-3. The cured coating films formed with the compositions of each example had excellent physical properties, namely:
It can be seen that it has good antifogging performance over a long period of time while having sufficient surface hardness and wear resistance. On the other hand, each comparative example had a problem in one of the physical properties.

That is, Comparative Example 1, which does not contain component (B), has excellent abrasion resistance but is inferior in antifogging performance. Comparative Example 2, which contains too much component (B), has excellent antifogging performance, but has a problem with abrasion resistance. Moreover, Comparative Examples 3 and 4, which do not contain component (A), have excellent antifogging performance, but are significantly inferior in abrasion resistance.

(Test items) ■Appearance Transparency 1 Coloring 1 The surface condition was examined by visual observation.

■ Use a knife to make 100 gongs on the coating surface of the adhesion test piece that reach the base material of 1 mm square, firmly stick cellophane adhesive tape (trade name "Cello Tape" manufactured by Nichiban ■), and make a right angle. The film was quickly peeled off in the direction of the film, and the presence or absence of peeling of the coating film was evaluated as good or bad.

■Surface hardness Measured using a pencil scratch hardness tester (load: 1 kg) according to JIS K-5400, and showed the highest pencil hardness without scratches.

(2) Scratch Resistance The surface was rubbed with #0OOOO Steel Cool and evaluated as follows.

A: Almost no damage.

B: Slight damage.

C: Severely damaged.

■Anti-fogging performance ■It is judged by the state of cloudiness when breath is blown onto a test piece placed in an atmosphere of 25° C. and 60-65% RH (hereinafter referred to as room temperature) for 3 seconds.

O: No clouding occurs at all.

Δ: Clouding occurs, but disappears within 5 seconds.

X:! It takes longer than 5 seconds for the paste to disappear. ■ Shine boiling water vapor on a coating film test piece kept at room temperature for 5 seconds, and judge based on the cloudiness. ○: No clouding occurs at all.

△: Water droplets are attached, but the particles are large and transparency is not lost.

X: Clouding occurs due to adhesion of minute water droplets.

(2) After being left at a temperature of -20°C for 30 minutes, it is taken out to room temperature and judged based on the cloudiness.

O: No fogging occurs at all, or fogging disappears within 30 seconds.

△: Clouding disappears within 2 minutes.

×：! It takes longer than 2 minutes for the glue to disappear. (2) Durability test of anti-fog performance After immersing the specimen in warm water at 80°C for 30 minutes, the anti-fog performance test described above is conducted.

■Dyeing property: Add 0.4 parts of dye (product name: "Dianics, Brown R-EJ, manufactured by Mitsubishi Chemical Industries ■) to 100 parts of warm water at 85°C. After stirring, immerse the test piece for 10 minutes, and judge by the density of the dyeing. did.

○: Quite darkly dyed.

△: Lightly dyed.

×: Hardly dyed.

Claims (1)

[Scope of Claims] Each of the following components (B), (C), and (D) is blended with the following component (A) in the following amounts, and the above-mentioned (A) and (B)
An antifogging coating composition characterized in that each component exists as a hydrolysis reaction product. (A) An organosilicon compound into which a non-hydrolyzable organic group having an epoxy group and at least two hydrolyzable groups are introduced. (B) General formula R^1O-(CH_2CH_2O)_n(CH_2)_
3-Si-(OR^2)_3 (However, R^1 is carbon number 1
an organic group having ~4 alkyl groups or epoxy groups, R
^2 is an alkyl group with 1 to 4 carbon atoms, n is an integer of 3 to 30) Organosilicon compounds into which an ethylene oxide polymer is introduced, or general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, R^1 and R^2 are alkyl groups having 1 to 4 carbon atoms,
At least one organosilicon compound into which an ethylene oxide polymer represented by n is an integer of 3 to 30 is introduced...30 to 30 parts by weight per 100 parts by weight of component (A) above.
150 parts by weight. (C) At least one unsaturated or saturated polyhydric carboxylic acid or anhydride thereof...the above (A) and (B)
0.0% as a carboxylic acid based on the epoxy group contained in the component.
1 to 1 equivalent. (D) Curing agent: 0.3 to 5.0 parts by weight per 100 parts by weight of component (A).