JP2023024372A - Coating formation method and laminated coating - Google Patents

Abstract

To provide a coating formation method capable of forming a coating excellent in coating film physical properties such as whitening resistance.SOLUTION: In the coating formation method for coating a colored pattern surface with an aqueous clear coating material, the aqueous clear coating material contains a resin component (A) and a crosslinking agent (B). The resin component (A) contains an acrylic resin (A1) in which the content of a carboxy group-containing monomer in a resin-constituting component is 5 wt.% or less. The crosslinking agent (B) is a carbodiimide compound. The carbodiimide compound is contained in an amount of 0.1-10 pts.wt. in terms of solid content based on 100 pts.wt. of the solid content of the resin component (A).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a novel film forming method and a laminated film.

In recent years, environmental concerns such as the reduction of volatile organic compounds (VOC) have been increasing, and in the coating field, there is a shift from solvent-based coating materials using organic solvents to water-based coating materials.

One of the problems with water-based coating materials such as those described above is the improvement of physical properties of coating films such as stain resistance and water resistance. Techniques related to introduction of a cross-linking agent have been proposed to address such problems (for example, Patent Document 1). However, by simply introducing a cross-linking agent, whitening resistance may not be obtained, or a rigid coating film may be formed, resulting in poor conformability to the substrate. In particular, when the clear coating material (topcoat) is insufficient in whitening resistance and conformability to the substrate, there is a risk of impairing the design properties such as the colored pattern of the substrate, and there is room for improvement.

WO2017/006950

The present invention has been made in view of the above-mentioned problems, and by applying a specific water-based clear coating material to a colored pattern surface, a coating excellent in physical properties such as whitening resistance can be obtained. It is an object of the present invention to provide a method for forming a film that can be formed.

In order to solve the above-mentioned problems, the present inventors, as a result of intensive studies, applied a water-based clear coating material containing a specific acrylic resin as a resin component and a carbodiimide compound as a cross-linking agent in a specific weight ratio to the colored pattern surface. The present invention has been completed by conceiving a method for forming a coating film and a laminated coating film thereof.

That is, the present invention has the following features.
1. A method for forming a film by applying a water-based clear coating material to a colored patterned surface,
The water-based clear coating material contains a resin component (A) and a cross-linking agent (B),
The resin component (A) contains an acrylic resin (A1) in which the content of the carboxy group-containing monomer in the resin component is 5% by weight or less,
The cross-linking agent (B) is a carbodiimide compound,
A method for forming a film, wherein the resin component (A) contains 0.1 to 10 parts by weight of a carbodiimide compound in terms of solid content with respect to 100 parts by weight of the solid content of the resin component (A).
2. The resin component (A) includes an acrylic resin (A1) in which the content of the carboxy group-containing monomer in the resin component is 5% by weight or less, and the acrylic resin in which the content of the carboxy group-containing monomer in the resin component is the acrylic resin 1. Characterized by containing more acrylic resin (A2) than (A1). The film forming method according to .
3. 1. The solid content of the resin component (A) contains 55% by weight or more of the acrylic resin (A1) in terms of solid content. or 2. The film forming method according to .
4. 1. Further, the organic amine compound is included as the basic organic compound (C). or 2. The film forming method according to .
5.1. or 2. A laminated coating formed by the method for forming a coating according to 1.

According to the film forming method of the present invention, by applying a specific water-based clear coating material to a colored pattern surface, a laminated film having excellent physical properties such as whitening resistance can be formed. Thereby, the designability of the colored pattern surface can be maintained for a long period of time.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated.

In the film forming method of the present invention, by applying a specific water-based clear coating material to the colored pattern surface, whitening resistance and the like are enhanced, and the design (colored pattern) of the colored pattern surface is maintained for a long period of time. can be done.

<Colored pattern side>
The colored pattern surface of the present invention has a colored pattern on a substrate. Examples of the substrate include concrete, mortar, and plate-like substrates. Among these, plate-like substrates include, for example, cement boards, extruded boards, slate boards, PC boards, ALC boards, fiber-reinforced cement boards, metal siding boards, ceramic siding boards, ceramic boards, calcium silicate boards, Examples include plastic boards, hardwood cement boards, PVC extruded siding boards, and plywood. The surface of these substrates may have been subjected to some surface treatment (for example, sealer, surfacer, filler, etc.), or may have a coating film already formed, or may have wallpaper attached. .

A colored pattern is a multicolored pattern in which at least two or more colors are visible in a mixed state. Scattered patterns, patterns that are painted in two or more colors (e.g., island pattern, line pattern, tile pattern, brick pattern, stone pattern, rock pattern, wood pattern, geometric pattern, striped pattern, grid pattern, random pattern, etc.). According to the film forming method of the present invention, even in such a multicolor pattern having at least two colors, the contrast can be maintained, and the design (colored pattern) can be maintained for a long period of time. can be done.

The colored pattern may be formed by various printing methods (inkjet printing, etc.), or may be formed by various coating materials. In the present invention, it is preferable to use a covering material (in particular, a decorative covering material). Specific examples of such a decorative coating material include a stone-like finish coating material and a multicolored pattern paint of JIS K5667. According to such a decorative covering material, a colored (multicolored) pattern can be formed with a single material.

[Stone finish finish]
The stone-like finishing coating material in the present invention is a coating material capable of forming a colored (multicolor) pattern by coloring the aggregate, and is a coating material containing a synthetic resin emulsion and an aggregate as essential components. Among these, synthetic resin emulsions include, for example, vinyl acetate resin, epoxy resin, silicone resin, acrylic resin, urethane resin, acrylic urethane resin, acrylic silicone resin, fluororesin, or composites thereof. In the present invention, the synthetic resin emulsion preferably contains a functional group (for example, a carboxyl group) reactive with the carbodiimide compound (B) described below as a constituent component. Thereby, the effect of the present invention can be enhanced.

As the aggregate, at least one selected from natural aggregate such as natural stone, pulverized natural stone, and artificial aggregate such as colored aggregate can be preferably used. Specifically, for example, marble, granite, serpentinite, granite, fluorite, cold water stone, feldspar, limestone, silica, silica sand, crushed stone, mica, siliceous shale, and pulverized products thereof, pulverized ceramics, and pulverized ceramics materials, glass pulverized materials, glass beads, resin pulverized materials, resin beads, rubber grains, metal grains, and the like. Crushed materials such as shells, coral, wood, charcoal and activated carbon can also be used. Furthermore, the surface of these materials may be colored and coated by surface treatment with a pigment, dye, glaze, or the like. By using two or more of such aggregates in appropriate combination, various multicolor patterns can be produced.

The particle size of the aggregate is preferably 0.01 mm to 5 mm (more preferably 0.03 mm to 4.5 mm). The mixing ratio of the aggregate is preferably 100 to 4000 parts by weight (more preferably 150 to 3000 parts by weight, still more preferably 200 to 2000 parts by weight) per 100 parts by weight of the solid content of the synthetic resin emulsion.

In addition, components other than those described above can be mixed in the stone-like finish coating material. Examples of such components include coloring pigments, extender pigments, fibers, film-forming aids, plasticizers, antifreeze agents, preservatives, antifungal agents, antibacterial agents, antifoaming agents, pigment dispersants, and thickeners. , leveling agents, wetting agents, pH adjusters, matting agents, catalysts, cross-linking agents, ultraviolet absorbers, light stabilizers and the like.

The stone-like finish coating material can be applied by, for example, spray coating, roller coating, trowel coating, brush coating, or the like, and one or more coating materials may be applied in layers. In such a stone-like finish coating material, it is possible to impart various uneven patterns by appropriately selecting and adjusting coating tools, coating conditions, and the like. Moreover, it is also possible to cut the convex portions with a sander or the like after drying the coating film. Tile patterns, geometric patterns and the like can also be formed by the use of joint bars, joint forms and the like.

The coating amount of the stone-like finish coating material is preferably 1 to 10 kg/m ² . At the time of application, a diluent such as water can be mixed to appropriately adjust the viscosity of the coating material. The dilution ratio is preferably about 0 to 10% by weight. Drying of the stone-like finish coating material is preferably carried out at room temperature.

[Colorful pattern paint]
Multicolor paints are obtained by suspending two or more liquid or gel color particles in a dispersion medium. These are (1) oil-in-water type (O / W type), (2) water-in-oil type (W / O type), (3) oil-in-oil type (O / O type), (4) water-in-water type (W /W type).

Color particles in the multicolored paint are obtained by dispersing a colored paint containing a resin, a coloring pigment, and various additives as necessary in a dispersion medium in a granular form. Examples of the resin in the colored paint include acrylic, urethane, vinyl acetate, acrylic vinyl acetate, acrylic urethane, acrylic silicon, fluorine, polyvinyl alcohol, biogum, galactomannan derivatives, alginic acid derivatives, cellulose derivatives and the like. These resins may be in the form of solvent-soluble resins, non-water-dispersible resins, water-soluble resins, water-dispersible resins, or the like. Moreover, these resins may have functional groups that can be crosslinked by a curing agent or a curing catalyst.

Coloring pigments in colored paints include, for example, titanium oxide, zinc oxide, carbon black, lamp black, bone black, graphite, black iron oxide, copper chromium black, cobalt black, copper manganese iron black, red iron oxide, molybdate orange, Permanent red, permanent carmine, anthraquinone red, perylene red, quinacridone red, yellow iron oxide, titanium yellow, fast yellow, benzimidazolone yellow, chrome green, cobalt green, phthalocyanine green, ultramarine blue, dark blue, cobalt blue, phthalocyanine blue, quinacridone Violet, dioxazine violet, aluminum pigments, pearl pigments and the like can be mentioned, and one or more of these can be used.

Known additives can be appropriately used in the colored paint. Such additives include, for example, extender pigments, viscosity modifiers, cross-linking agents, catalysts, fillers, fibers, pigment dispersants, film-forming aids, antifreeze agents, drying modifiers, plasticizers, matting agents, antifoaming agents, antifungal agents, preservatives, ultraviolet absorbers, light stabilizers and the like.

The method for dispersing the colored paint into particles is not particularly limited, and any known method can be employed. Specifically, a method of dispersing a colored paint in a dispersion medium containing a dispersion stabilizer or the like can be employed. The dispersion medium can also contain a resin, and for example, those mentioned in the above colored paint can be used. The resin in the dispersion medium preferably contains a functional group (for example, a carboxyl group) reactive with the carbodiimide compound (B) described below. Thereby, the effect of the present invention can be enhanced. Although the particle size of the color grains is not particularly limited, it is preferably 0.01 to 10 mm (more preferably 0.1 to 5 mm).

As a method for applying the multicolored pattern paint, for example, spray coating, roller coating, brush coating and the like can be employed. The application amount of the multicolor paint is preferably 0.2 to 1 kg/m ² . At the time of application, a diluent such as water can be mixed to appropriately adjust the viscosity. The dilution ratio is preferably about 0 to 10% by weight. Drying of the multicolored pattern paint is preferably carried out at room temperature.

In the present invention, it is also possible to form a colored pattern (multicolored pattern) by combining two or more kinds of colored coating materials having different colors. As a coloring coating material, a synthetic resin emulsion is used as a binder, a coloring pigment is added to this, and if necessary, an extender pigment, an aggregate, other admixtures (dispersant, thickener, antifoaming agent, preservative, etc.), etc. is obtained by uniformly mixing

Among these, as the synthetic resin emulsion, it is possible to use the same one as the above-mentioned stone finish topcoat material, preferably a functional group (for example, a carboxyl group) having reactivity with the carbodiimide compound (B) described later. You can use anything that contains As the color pigment, the same ones as those of the multicolor paint described above can be used, and a desired color can be expressed by using one or a combination of two or more thereof. The mixing ratio of the color pigment is preferably about 1 to 300 parts by weight (more preferably 2 to 200 parts by weight) per 100 parts by weight of the solid content of the synthetic resin emulsion.

In the coating of such a coating material, various patterns can be formed by appropriately selecting the type of coating tool and the method of using it. Examples of coating tools that can be used include sprays, rollers, and trowels. At this time, by treating the coated surface with a design roller, a trowel, a brush, a comb, a spatula, etc. until the coating material dries, various uneven patterns can be formed. In addition, tile patterns, geometric patterns, and the like can be formed by using joint bars, joint forms, and the like.

The coating amount is preferably about 0.03 to 10 kg/m ² although it depends on the type of pattern to be formed. At the time of application, a diluent such as water can be mixed to appropriately adjust the viscosity of the coating material. The dilution ratio is preferably about 0 to 10% by weight. Drying is preferably carried out at room temperature.

<Aqueous clear coating material>
The aqueous clear coating material of the present invention (hereinafter also simply referred to as "coating material") is characterized by containing a resin component (A) and a cross-linking agent (B).

The resin component (A) (hereinafter also referred to as "(A) component") of the present invention is an acrylic resin (A1) (hereinafter referred to as " (Also referred to as "component (A1)"). By including such a component (A1), it is possible to exhibit excellent effects in terms of whitening resistance and the like.

The (A1) component of the present invention contains a (meth)acrylic acid alkyl ester as a main component of the resin component, and as other monomer components, the content of a carboxy group-containing monomer is 5% by weight or less (more preferably 0 to 4.8% by weight, more preferably 0.05 to 4.5% by weight, particularly preferably 0.1 to 3% by weight). In such a range, good physical properties of the film can be obtained. When the component (A1) has a carboxyl group-containing monomer, the whitening resistance can be further enhanced by cross-linking the component (B), which will be described later. In the present invention, alkyl acrylate and alkyl methacrylate are collectively referred to as alkyl (meth)acrylate. Moreover, a monomer is a general term for compounds having a polymerizable unsaturated double bond. In the present invention, "α to β" has the same meaning as "more than or equal to α and less than or equal to β".

Examples of (meth)acrylic acid alkyl esters include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) Acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, cyclohexyl (meth)acrylate and the like can be mentioned, and one or more of these can be used.

Examples of carboxyl group-containing monomers include
Carboxy group-containing monomers such as (meth)acrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, isocrotonic acid, salicylic acid and the like can be mentioned, and one or more of these can be used.

Specific examples of other monomers include, for example,
aromatic monomers such as styrene, 2-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene, vinylanisole, vinylnaphthalene, divinylbenzene, phenyl (meth)acrylate, benzyl (meth)acrylate;
Nitrile group-containing monomers such as (meth)acrylonitrile, vinylidene cyanide, α-cyanoethyl (meth)acrylate;
Maleic acid amide, (meth)acrylamide, N-monoalkyl (meth)acrylamide, N,N-dialkyl (meth)acrylamide, 2-(dimethylamino)ethyl (methacrylate), N-[3-(dimethylamino)propyl] Amide group-containing monomers such as (meth)acrylamide and vinylamide;
Carbonyl group-containing monomers such as acrolein, diacetone (meth)acrylamide, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone;

aminomethyl acrylate, aminoethyl acrylate, aminopropyl (meth)acrylate, amino-n-butyl (meth)acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N-methylaminoethyl (meth)acrylate, N - amino group-containing monomers such as t-butylaminoethyl (meth)acrylate;
glycidyl (meth) acrylate, diglycidyl fumarate, 3,4-epoxycyclohexyl (meth) acrylate, 3,4-epoxyvinylcyclohexane, allyl glycidyl ether, ε-caprolactone-modified glycidyl (meth) acrylate, β-methylglycidyl (meth) ) epoxy group-containing monomers such as acrylates;
hydroxyl group-containing monomers such as hydroxypropyl (meth)acrylate, ethylene glycol mono (meth) acrylate, glycerol mono (meth) acrylate;
vinylidene halide-based monomers such as vinylidene fluoride;
Alkoxysilyl groups such as vinyltrimethoxysilane, vinyltriethoxysilane, γ-(meth)acryloyloxypropyltrimethoxysilane, γ-(meth)acryloyloxypropyltriethoxysilane, γ-(meth)acryloyloxypropylmethyldimethoxysilane, etc. contained monomers;
ethylene, propylene, isoprene, butadiene, vinyl ether, vinyl ketone; and the like. These can be used singly or in combination of two or more.

In the present invention, the other monomer component is preferably an acrylic silicone resin containing an alkoxysilyl group-containing monomer. In such a case, film physical properties such as weather resistance, stain resistance and water resistance can be enhanced.

Examples of the form of the component (A1) include water-soluble resins, water-dispersible resins, and composites thereof. In the present invention, a water-dispersible resin (resin emulsion) is preferred.

Component (A1) can be produced by a single-stage or multi-stage (two-stage, or three-stage or more) emulsion polymerization method or the like from a group of monomers obtained by appropriately mixing the above-mentioned monomers. As the polymerization method, a known method may be adopted, and in addition to ordinary emulsion polymerization, soap-free emulsion polymerization, feed emulsion polymerization, seed emulsion polymerization, and the like can also be adopted. At the time of polymerization, emulsifiers, initiators, dispersants, polymerization inhibitors, polymerization inhibitors, buffers, chain transfer agents and the like can be used.

As the emulsifier, various surfactants that can be used for emulsion polymerization can be used, and these may be reactive type having a polymerizable unsaturated double bond (reactive surfactant). As emulsifiers, anionic surfactants and nonionic surfactants are preferably used alone or in combination.

The glass transition temperature (hereinafter simply referred to as “Tg”) of the component (A1) is preferably set to −5° C. to 80° C. (more preferably 0 to 60° C.). If Tg is within such a range, the effects of the present invention can be stably obtained. In addition, Tg in the present invention is a value obtained by the Fox equation.

The average particle size of the acrylic resin of component (A1) is preferably 300 nm or less (more preferably 20 to 200 nm). If the average particle size is within such a range, the water resistance, weather resistance, chemical resistance, etc. of the coating can be improved. The average particle size referred to here is a value measured by a dynamic light scattering method.

Furthermore, the pH of the emulsion solution of component (A1) is preferably 7.0 or higher (more preferably 7.5 to 12, and still more preferably 8.0 to 11). In such a range, the stability of the covering material can be ensured.

The content of the component (A1) is preferably 55% by weight or more (more preferably 60 to 99.99% by weight, more preferably 60 to 99.99% by weight, more preferably 80 to 99.98% by weight, particularly preferably 90 to 99.95% by weight). The component (A1) is a main binder component in the component (A), and when the component (A1) satisfies the above range, it is advantageous for whitening resistance. In addition, it is possible to sufficiently secure film physical properties such as substrate followability, weather resistance, stain resistance, and water resistance.

In the present invention, it is preferable to include an acrylic resin (A2) (hereinafter also referred to as "(A2) component") having a higher content of carboxyl group-containing monomers than (A1) in the resin component. By including the component (A1) and the component (A2) in combination, it is possible to exhibit a more excellent effect in terms of whitening resistance.

The (A2) component of the present invention contains a (meth)acrylic acid alkyl ester as a main component of the resin component, and has a higher content of carboxy group-containing monomers in the resin component than the (A1) component ( preferably 3 to 80% by weight, more preferably 6 to 70% by weight, still more preferably 10 to 60% by weight). Within such a range, whitening resistance can be improved by a cross-linking reaction with a cross-linking agent (B) described later.

Examples of the form of the component (A2) include water-soluble resins, water-dispersible resins, and composites thereof. In the present invention, a water-dispersible resin (resin emulsion) is preferred. In addition, the (A2) component can be produced by the same method as for the (A1) component. The average particle size of the acrylic resin of component (A2) is preferably 300 nm or less (more preferably 20 to 200 nm). The average particle size referred to here is a value measured by a dynamic light scattering method.

Further, the component (A2) is preferably a resin (alkali-soluble or alkali-swellable resin) that dissolves or swells with alkali (neutralization). Thereby, the whitening resistance can be further improved. This mechanism of action is not limited to the following, but in the embodiment containing the (A1) component and the (A2) component having different contents of the carboxy group-containing monomer, the dissolved or swollen (A2) component is the above (A1 ), it is considered that the crosslinked structure of the film becomes partially dense when crosslinked with the crosslinking agent (B), which will be described later. This makes it possible to improve the whitening resistance without impairing the physical properties of the film such as the conformability to the substrate imparted by the component (A1).

The pH of the emulsion solution before neutralization of the component (A2) is preferably less than 7 (more preferably 6 or less, more preferably 1 to 4), and by mixing with the component (A1), dissolution or It swells and the above effect can be obtained. The average particle size of the acrylic resin of the component (A2) is a measured value before being dissolved or swollen by alkali (neutralization).

The content of the component (A2) is 45 wt% or less (more preferably 0.01 to 40 wt%, preferably 0.02 ~20% by weight, more preferably 0.05 to 10% by weight). The above component (A2) is a binder component that acts auxiliary to the above component (A1). When the above range is satisfied, it is advantageous for whitening resistance, and whitening resistance is achieved by crosslinking of the component (B) described later. can be further enhanced.

In the present invention, a carbodiimide compound is included as the cross-linking agent (B), and the carbodiimide compound is added in an amount of 0.1 to 10 parts by weight (preferably 0.1 to 10 parts by weight in terms of solid content) per 100 parts by weight of the solid content of the resin component (A). 2 to 5 parts by weight). In such a case, a coating excellent in whitening resistance and the like can be formed by cross-linking reaction with the resin component (A) (the (A1) component and the (A2) component).

Examples of such carbodiimide compounds include carbodiimide group-containing resins, N,N-dicyclohexylcarbodiimide, and N,N-diisopropylcarbodiimide. Examples of the carbodiimide group-containing resin include those described in JP-A-10-60272, JP-A-10-316930, JP-A-11-60667, WO2017/006950, and the like. The form of the carbodiimide compound is preferably water-soluble or water-dispersible, and the water-dispersible form is particularly advantageous in terms of storage stability.

The carbodiimide equivalent of the carbodiimide compound is preferably 100-500 (more preferably 150-400). Within such a range, the effect of the present invention can be sufficiently obtained.

In the present invention, in addition to the above components, it is preferable to include a basic organic compound (C) (hereinafter also referred to as “component (C)”). Component (C) includes, for example, alkylamines [e.g., monomethylamine, dimethylamine, trimethylamine, monoethylamine, triethylamine, monoisopropylamine, diisopropylamine, butylamine, diethylenetriamine, triethylenetriamine, triethylenetetramine, etc.], alcohol Amines (aminoalcohols) [e.g., monoethanolamine, methylethanolamine, ethylethanolamine, mono-n-butylethanolamine, aminoethylpropanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, dimethylethanolamine, 2-aminomethylpropanol, etc.], heterocycle-containing amines [eg, morpholine, methylmorpholine, piperazine, hydroxyethylpiperazine, etc.]. These can be used singly or in combination of two or more. The component (C) may be added as a neutralizing agent during the production of the component (A). In the present invention, alcoholamines (aminoalcohols) are preferred, and 2-aminomethylpropanol, diethanolamine, monoethanolamine and the like are particularly preferred.

The boiling point of the organic amine compound is preferably 80° C. or higher (more preferably 100° C. or higher, more preferably 150° C. or higher). When the above range is satisfied, the rate of volatilization during film formation becomes moderate, so a film with excellent whitening resistance can be formed.

By containing the component (C), a dense coating can be formed. Although this action mechanism is not limited to the following, the cross-linking reaction of the carbodiimide compound (B) tends to speed up as the pH decreases. On the other hand, when a basic organic compound is added, its volatilization rate is moderate, so the cross-linking reaction (curing rate) due to a rapid decrease in pH is suppressed. A cross-linking reaction occurs. As a result, a dense coating can be formed, and whitening resistance can be further improved.

The content of component (C) is 0.01 to 5 parts by weight (0.02 to 3 parts by weight) per 100 parts by weight of the solid content of component (A). In the case of such a range, the above effects can be sufficiently exhibited.

The coating material of the present invention can be produced by uniformly mixing the above components by a known method, but if necessary, other components that are commonly used in coating materials can also be mixed. Examples of such components include coloring pigments, extender pigments, fibers, film-forming aids, thickeners, leveling agents, coupling agents, plasticizers, antifreeze agents, pH adjusters, preservatives, and antifungal agents. , anti-algae agents, antibacterial agents, dispersants, antifoaming agents, ultraviolet absorbers, light stabilizers, antioxidants, water, and the like.

The coating material of the present invention is a water-based clear coating material that forms a transparent coating, that is, a coating that transmits visible light. As a result, it is possible to form a laminated film having transparency, and to obtain a finish that takes advantage of the design of the base. The transparency may be such that the color and pattern of the base can be visually recognized, and the coating may be either colorless and transparent, or colored and transparent. (including split gloss etc.). A colored transparent film can be formed from a coating material containing, for example, a coloring pigment, a dye, or the like. A matte coating can be formed by a coating material containing, for example, an extender, a matting agent, or the like.

The degree of visible light transmission can be indicated by visible light transmittance. Visible light transmittance is preferably 30% or more, more preferably 35 to 100%, still more preferably 40 to 95%. The visible light transmittance is a value obtained by measuring the transmittance of light with a wavelength of 580 nm for a film with a thickness of 30 μm using a spectrophotometer (transmittance is 100% when there is no film (air)). be.

In order to obtain such visible light transmittance, for example, the coloring pigment ratio in the covering material should be set low. The coloring pigment ratio in the coating material is preferably 10% by weight or less, more preferably 5% by weight or less, and still more preferably 0 to 3% by weight. Embodiments in which the coating material does not contain a coloring pigment are also suitable.

In applying the water-based clear coating material of the present invention, a known coating tool can be used. Examples of coating tools that can be used include sprays, rollers, and brushes. The coating amount of the aqueous clear coating material is preferably 0.05-0.8 kg/m ² (more preferably 0.08-0.5 kg/m ² ). The number of times the water-based clear coating material is recoated is preferably 1 to 3 times. At the time of coating, the water-based clear coating material can be diluted as needed. Drying after application of the water-based clear coating material may be carried out at room temperature (preferably 0 to 50°C, more preferably 5 to 45°C), and heating can be performed if necessary.

<Laminate coating>
The laminated film of the present invention is formed by applying the water-based clear coating material to the colored pattern surface. In the present invention, by applying the water-based clear coating material to the colored patterned surface, whitening resistance and the like are enhanced, and the design (colored pattern) of the colored patterned surface can be maintained for a long period of time. In particular, when the colored pattern surface has two or more colors, the contrast can be maintained, and the design (colored pattern) can be maintained for a longer period of time.

Examples are shown below to further clarify the features of the present invention.

・Production of stone finish coating material 200 parts by weight of carboxy group-containing acrylic resin emulsion (solid content: 50% by weight), 210 parts by weight of calcium carbonate, aggregates (yellow aggregate, black aggregate, brown aggregate, Kansui stone) mixture) 550 parts by weight, 10 parts by weight of film-forming aid, 4 parts by weight of viscosity modifier, 2 parts by weight of antifoaming agent, and 110 parts by weight of water were uniformly mixed by a conventional method to obtain a stone-like finish coating material. .

・Manufacturing multicolored paint Granules of colored paint containing as a main component, particle size about 1 mm) brown particles: black particles = 8: 2 (weight ratio), dispersed in an aqueous medium containing a carboxy group-containing acrylic resin emulsion Multicolor pattern paint (water-in-water type).

・Manufacturing of water-based clear coating materials
Based on the formulation shown in Table 1, each raw material was mixed by a conventional method to produce a water-based clear coating material.
In addition, each component used the following.

(A) Resin component Resin 1: Acrylic resin emulsion (cyclohexyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, emulsion polymer of acrylic acid, content of carboxy group-containing monomer: 0.5% by weight, average particle size: 120 nm , solid content: 50% by weight, medium: water, pH = 8.5)
・Resin 2: Acrylic resin emulsion (emulsion polymer of cyclohexyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, acrylic acid, γ-methacryloyloxypropyltrimethoxysilane, content of carboxy group-containing monomer: 0.5% by weight, average Particle diameter: 120 nm, solid content: 50% by weight, medium: water, pH = 8.5)
Resin 3: Acrylic resin emulsion (emulsion polymer of cyclohexyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, acrylic acid, γ-methacryloyloxypropyltrimethoxysilane, content of carboxy group-containing monomer: 0.1% by weight, average Particle diameter: 120 nm, solid content: 50% by weight, medium: water, pH = 8.5)
・ Resin 4: Acrylic resin emulsion (emulsion polymer of cyclohexyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, acrylic acid, γ-methacryloyloxypropyltrimethoxysilane, content of carboxy group-containing monomer: 1.5% by weight, average Particle diameter: 120 nm, solid content: 50% by weight, medium: water, pH = 8.5)
・ Resin 5: Acrylic resin emulsion (emulsion polymer of cyclohexyl methacrylate, 2-ethylhexyl acrylate and methyl methacrylate, content of carboxy group-containing monomer: 0% by weight, average particle size: 120 nm, solid content: 50% by weight, medium: water, pH=8.5)
・ Resin 6: Acrylic resin emulsion (cyclohexyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, emulsion polymer of acrylic acid, content of carboxy group-containing monomer: 6% by weight, average particle size: 120 nm, solid content: 50% by weight , medium: water, pH = 8.5)
Resin 7: Alkali-swellable acrylic resin emulsion (emulsion polymer of ethyl acrylate, ethyl methacrylate, methacrylic acid, content of carboxy group-containing monomer: 30% by weight, average particle size: 80 nm, solid content: 30% by weight, medium : water, pH = 3.0)

(B) Crosslinking Agent/Crosslinking Agent 1: Carbodiimide resin aqueous dispersion (solid content: 40% by weight, carbodiimide equivalent: 310)
· Cross-linking agent 2: carbodiimide resin aqueous dispersion (solid content: 40% by weight, carbodiimide equivalent: 230)
· Crosslinking agent 3: carbodiimide resin aqueous solution (solid content: 40% by weight, carbodiimide equivalent: 335)
· Crosslinking agent 4: carbodiimide resin aqueous dispersion (solid content: 40% by weight, carbodiimide equivalent: 450)
(C) basic organic compound/basic organic compound 1: 2-aminomethylpropanol (boiling point: 165°C)
・ Basic organic compound 2: 25% ammonia water (boiling point: 100 ° C.)
(others)
・Matting agent: acrylic bead powder (average particle size: 10 μm)
・Additives (urethane associative thickeners, defoaming agents, UV absorbers, etc.)
・Media: Water, hydrophilic solvent

(Colored pattern surface)
・On a base material (slate plate: 45 x 30 cm), a stone-like finish coating material is sprayed at a coating amount of 5.0 kg / m ² and dried at 23 ° C. for 24 hours. bottom.
A colored pattern surface 2 was obtained by spraying a multicolor pattern paint onto a substrate (slate plate: 45×30 cm) at a coating amount of 0.5 kg/m ² and drying at 23° C. for 24 hours.

(Examples 1 to 20, Comparative Examples 1 to 3)
A water-based clear coating material was spray-coated on the colored pattern surface with a spray gun at a coating amount of 0.3 kg/m ² , dried and cured at 23°C for 24 hours to form a test sample [I]. The following whitening resistance evaluation was performed on the produced test specimen [I]. Table 2 shows the combination of the colored pattern surface and the water-based clear coating material and the evaluation results.

<Whitening resistance evaluation 1>
Specimen [I] was immersed in water (23° C.) for 7 days, and the presence or absence of whitening immediately after pulling out was confirmed. As the evaluation criteria, a 4-grade evaluation (excellent: A>B>C>D: poor) was used, with "A" indicating no whitening and "D" indicating whitening of the entirety.

<Whitening resistance evaluation 2>
Specimen [I] was immersed in water (23°C) for 7 days, pulled out, dried for 24 hours (23°C), and then examined for whitening. The evaluation criteria are the same as those for whitening resistance evaluation 1.

In Examples 1 to 20, sufficient whitening resistance could be obtained, and the design (color contrast) of the colored patterned surface could be maintained. In particular, in Examples 7 to 13 and 17 to 19, whitening resistance evaluations 1 and 2 were both "A" evaluations.

Next, for Examples 1 to 20, film physical property evaluation (stain resistance evaluation) was performed. Results are shown in Table 2.
<Stain resistance evaluation 1>
A contaminant (15% by weight carbon aqueous solution) is spotted on the film surface of the test sample [I], dried for 24 hours (23 ° C.), washed with water for 10 minutes on the surface, and then washed for 6 hours (23 ° C.). After drying, the staining condition was evaluated. The evaluation criteria were as follows: "AA" for maintaining excellent aesthetics without surface contamination; "A" for maintaining excellent aesthetics with almost no surface contamination; A 5-grade evaluation (excellent: AA>A>B>C>D: inferior) was made with "D" indicating staining.

<Stain resistance evaluation 2>
A specimen [II] was used as the specimen after the whitening resistance evaluation 2, and the stain resistance evaluation was conducted. The evaluation method and evaluation criteria are the same as those of the contamination resistance evaluation 1.

<Stain resistance evaluation 3>
Specimen [III] was formed in the same manner as Specimen [I] except that an aqueous clear coating material stored at 50° C. for 30 days was used, and stain resistance evaluation was performed. The evaluation method and evaluation criteria are the same as those of the contamination resistance evaluation 1.

In Examples 1 to 15 and 17 to 19, sufficient stain resistance could be obtained, and the physical properties of the coating could be maintained even after being immersed in water. Moreover, in Examples 1 to 12, 14, and 17 to 19, the physical properties of the coating could be sufficiently maintained even after storage of the aqueous coating material.

<Follow-up evaluation>
<Preparation of test sample [IV]>
Two colored patterned surfaces were placed side by side, and a modified silicone-based sealing material (resin component: alkoxysilyl group-containing polyether polymer) was filled in the connecting portion (width 20 mm) between the plate materials as a base material to be painted.
A water-based clear coating material was spray-coated on the entire surface of the base material with a spray gun at a coating amount of 0.1 kg/m ² and dried for 3 days (5 ° C., humidity 30%). ]. With respect to the prepared test specimen [IV], the appearance of the film was confirmed, and the state of occurrence of defects (swelling, peeling, cracking, etc.) was evaluated. The evaluation was made into a four-grade evaluation (excellent: A>B>C>D: poor), with "A" indicating that no problem occurred and "D" indicating that a problem clearly occurred.

Claims (5)

A method for forming a film by applying a water-based clear coating material to a colored patterned surface,
The water-based clear coating material contains a resin component (A) and a cross-linking agent (B),
The resin component (A) contains an acrylic resin (A1) in which the content of the carboxy group-containing monomer in the resin component is 5% by weight or less,
The cross-linking agent (B) is a carbodiimide compound,
A method for forming a film, wherein the resin component (A) contains 0.1 to 10 parts by weight of a carbodiimide compound in terms of solid content with respect to 100 parts by weight of the solid content of the resin component (A). The resin component (A) includes an acrylic resin (A1) in which the content of the carboxy group-containing monomer in the resin component is 5% by weight or less, and the acrylic resin in which the content of the carboxy group-containing monomer in the resin component is the acrylic resin 2. The method of forming a film according to claim 1, wherein the acrylic resin (A2) is more than (A1). 3. The method of forming a film according to claim 1, wherein the solid content of the resin component (A) contains 55% by weight or more of the acrylic resin (A1) in terms of solid content. 3. The method of forming a film according to claim 1, further comprising an organic amine compound as the basic organic compound (C). A laminated film formed by the film forming method according to claim 1 or 2.