JPH09169933A - Designed coating film, its formation and decorative laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the design on the coating film having the top-coating layer resistant to damage. SOLUTION: The designed coating film 1 comprises the designed coating substrate layer 2 and the top coating layer 3 arranged on the substrate layer. The top coating layer 3 is formed by using a water-based cold-curable resin composition containing an acrylic emulsion containing groups reactive with isocyanate group and prepared by emulsion polymerization and a self- emulsification type polyisocyanate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative coating film, a method for forming the same, and a decorative plate, and more particularly to a decorative coating film having an overcoat layer, a method for forming the same, and a decorative plate.

[0002]

2. Description of the Related Art A decorative coating film may be formed on the outer wall of a building or the wall surface of a room in order to enhance the texture or impart design characteristics. The design coating is
Generally, stone, sandstone, porcelain, ceramics, porcelain,
It is mainly provided with a design coating film base layer formed in a design finish such as a enamel or cast finish, and an overcoat layer formed thereon for protecting the design coating film base layer. In addition, such a design coating film, by applying a decorative plate formed on a substrate having shape retention properties such as an aluminum plate using cement or an adhesive, It may be attached to the wall.

The overcoat layer used in the above-mentioned decorative coating film is generally formed by using an acrylic, acrylic-urethane or silicone resin paint (for example, Japanese Patent Laid-Open No. 57-27177). ). However, such an overcoat layer is not good in weather resistance and water resistance,
It is easy to bleach when exposed to sunlight and rainwater. For this reason, in the above-mentioned designable coating film, the whitening of the overcoat layer progresses over time, and the designability expressed by the designable coating film base layer is likely to be impaired.

An object of the present invention is to prevent the designability of a design coating film having an overcoat layer from being impaired.

[0005]

The designable coating film according to the present invention comprises a designable coating film base layer and an overcoat layer disposed on the designable coating film base layer. The overcoat layer is formed by using an aqueous room temperature curable resin composition containing an acrylic emulsion having a group capable of reacting with an isocyanate group and obtained by emulsion polymerization, and a self-emulsifying polyisocyanate.

Here, the hydroxyl value of the resin solid content of the acrylic emulsion used for the overcoat layer is, for example, 20 to 20.
0. The acrylic emulsion has a resin solid content acid value of 5 or less, for example. Furthermore, the acrylic emulsion is, for example, emulsion-polymerized using an emulsifier having a radically polymerizable unsaturated group.

The above-mentioned emulsifier has, for example, a hydrophilic group and a hydrophobic group in addition to the radically polymerizable unsaturated group. Here, the radically polymerizable unsaturated group is, for example, at least one selected from the group consisting of an allyl group, a propenyl group, an acryloyl group, a methacryloyl group and a maleoyl group. The hydrophilic group is, for example, at least one selected from the group consisting of a sulfuric acid group, a sulfonic acid group, a phosphoric acid group, a carboxyl group, and a polyoxyethylene group. Furthermore, the hydrophobic group is, for example, at least one selected from the group consisting of an alkyl group having 6 to 60 carbon atoms, an alkenyl group, an aralkyl group, an alkylaryl group, an aryl group, and a hydrocarbon group having these as side chains. .

Further, the self-emulsifying polyisocyanate used in the overcoat layer is, for example, an aqueous dispersion obtained by reacting a part of the isocyanate groups of an aliphatic or alicyclic polyisocyanate and its derivative with polyethylene oxide monoalkyl ether. It is a polyisocyanate having properties.

The method for forming a decorative coating film according to the present invention includes the steps of forming a decorative coating film base layer on a substrate and forming an overcoat layer on the decorative coating film base layer. The topcoat layer is formed by using an aqueous room temperature curable resin composition containing an acrylic emulsion having a group capable of reacting with an isocyanate group and obtained by emulsion polymerization, and a self-emulsifying polyisocyanate.

The decorative board according to the present invention comprises a substrate having a shape-retaining property, a decorative coating film base layer provided on the substrate, and an overcoat layer arranged on the decorative coating film base layer. The overcoat layer is formed by using an aqueous room temperature curable resin composition containing an acrylic emulsion having a group capable of reacting with an isocyanate group and obtained by emulsion polymerization, and a self-emulsifying polyisocyanate.

In this decorative plate, the substrate is, for example, an aluminum plate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Designed Coating A form of the designed coating according to the present invention is shown in FIG. In the figure, the designable coating film 1 is provided, for example, on an outer wall surface or an inner wall surface W of a building, and mainly includes a designable coating film base layer 2 and an overcoat layer 3 arranged thereon. ing.

(Designable Coating Base Layer 2) The above-mentioned designable coating base layer 2 is formed by using a designable coating material. The decorative coating material for forming the decorative coating film base layer 2 mainly contains a base resin and an aggregate.

As the base resin, various base resins usually used for paints can be used, but an acrylic resin emulsion is preferable from the viewpoint of manufacturability and coating film performance. The nonvolatile concentration of the acrylic resin emulsion is usually 40 to 6 in terms of workability and coating film performance.
0% by weight is preferred. The glass transition temperature of the acrylic resin emulsion is preferably 20 ° C or lower. When the glass transition temperature is higher than 20 ° C., the flexibility of the decorative coating base layer 2 is lowered, the followability to a curved surface is deteriorated, cracks are easily generated in the base layer, and there is a problem in workability.

As the acrylic resin emulsion, various ones can be used without particular limitation. For example, it is obtained by copolymerizing 43 parts by weight of methyl methacrylate, 42 parts by weight of 2-ethylhexyl acrylate and 15 parts by weight of styrene. Those having a nonvolatile concentration of 49% by weight and a glass transition temperature of 9 ° C. are preferably used.

The above-mentioned base resin is usually contained in the design paint in an amount of 8 to 25% by weight in terms of solid content.

The aggregate contained in the designable paint is a component for imparting a designability such as a desired pattern to the designable coating base layer 2. As this aggregate, in addition to general various extender pigments and coloring pigments, for example, natural stones such as marble, granite and limestone are crushed into granules, colored silica sand and ceramics fired with pigments are crushed into granules and colored. Ceramic powder is used.

Such an aggregate is usually contained in the design paint in an amount of 40 to 80% by weight.

A balloon may be included in the designable paint as required. This balloon is a hollow, fine-grained weight-reducing material, and is a component for reducing the weight of the decorative coating film base layer 2. The specific gravity of the balloon used here is 0.
02 to 0.5 is preferred. When the specific gravity is less than 0.02, the strength of the designable coating film base layer 2 decreases. On the contrary, when the specific gravity exceeds 0.5, it is difficult to obtain the effect of adding the balloon.

Preferred balloons include shirasu balloons, ceramic balloons, glass balloons, perlite and resin balloons. Shirasu balloons and ceramic balloons are obtained by heating and expanding volcanic glass particles containing silica, alumina or the like as a main component, and are usually spherical. On the other hand, a glass balloon is a glass material that is heated and foamed, and is usually spherical. Preferred shirasu balloons, ceramic balloons and glass balloons have a specific gravity of 0.07 to 0.5 and a particle size of 10 to 100 μm. Perlite is made by crushing and burning pearlite and has a specific gravity of 0.4 to 0.6.
Are preferred. As the resin balloon, a spherical micro hollow body made of a vinylidene chloride-acrylonitrile copolymer resin is preferable. Particularly, those having a specific gravity of 0.025 and a particle size peak of 32 to 80 μm are preferable.
Of these various balloons, it is preferable to use a resin balloon that is the most excellent as a lightweight material.

[0021] Balloons usually have a content of 0.2 in the design paint.
It is preferable to add about 0.8% by weight. 0.2 added
If it is less than wt%, it is difficult to sufficiently reduce the weight of the decorative coating film base layer 2. Conversely, if it exceeds 0.8% by weight,
The number of voids in the design coating film base layer 2 increases, and it becomes difficult to maintain the strength of the coating film.

The design coating film base layer 2 is prepared by appropriately selecting the particle size and the compounding ratio of the aggregate contained in the above-mentioned design coating material, or by appropriately selecting the viscosity and coating method of the design coating material. It is formed in a desired design tone, for example, stone tone such as granite or marble, sandstone tone, porcelain tone plate, pottery tone, porcelain tone, enamel tone or casting tone. If desired, a cut portion may be formed in the decorative coating film base layer 2 by using a sander or the like in order to impart three-dimensionality. The design paint can be applied by a coating method such as spray coating.

The thickness of the design coating film base layer 2 is the same as the design coating film 1
Can be appropriately set according to the part to which is applied,
Usually, it is 3 to 5 mm.

(Overcoat layer 3) The overcoat layer 3 is for protecting the above-mentioned decorative coating film base layer 2 and enhancing the durability of the decorative coating film 1. The overcoat layer 3 is formed using an aqueous room temperature curable resin composition containing an acrylic emulsion and a self-emulsifying polyisocyanate.

The acrylic emulsion used in the water-based room temperature curable resin composition for forming the overcoat layer 3 is obtained by emulsion-polymerizing an unsaturated monomer mainly containing an acrylic monomer as a raw material with an emulsifier. is there.

As a preferable unsaturated monomer used as a raw material for producing the above-mentioned acrylic emulsion, a monomer containing a hydroxyl group-containing unsaturated monomer as an essential component and, if necessary, an acid group-containing unsaturated monomer and other monomers A mixture may be mentioned. Examples of various monomers used in this monomer mixture include the following.

Unsaturated monomer containing hydroxyl group: hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, Praxel FM-1 (ε-caprolactone modified hydroxyethyl methacrylate manufactured by Daicel Chemical Industries, Ltd.), polyethylene glycol monoacrylate Or alcohols such as monomethacrylate, polypropylene glycol monoacrylate or monomethacrylate.

Acidic Group-Containing Unsaturated Monomers-Carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid and maleic acid. -Sulfonic acids such as 2-acrylamido-2-methylpropanesulfonic acid, sulfoethylmethacrylate, and styrenesulfonic acid, and salts thereof.

Other monomers: Esters of acrylic acid or methacrylic acid such as methyl, ethyl, propyl, butyl, hexyl, ethylhexyl and lauryl. -Esters of vinyl alcohol and carboxylic acids such as acetic acid and propionic acid.・ Styrene, α-methylstyrene, vinylnaphthalene,
Unsaturated hydrocarbons such as butadiene and isoprene. -Nitriles such as acrylonitrile and methacrylonitrile. -Amids such as acrylamide, methacrylamide, N-methylol acrylamide, N, N-dimethyl acrylamide, diacetone acrylamide. -Polyoxyalkylene derivatives such as polyethylene glycol methyl ether acrylate or methacrylate. * N, N-dimethyl-N-methacryloxyethyl-N-
Amphoteric compounds such as (3-sulfopropyl) -ammonium betaine. -Ethylene glycol, 1,4-butanediol, 1,
Diacrylates and dimethacrylates of glycols such as 6-hexanediol diethylene glycol. -Polyacrylates and polymethacrylates of polyols such as glycerin, trimethylolpropane and pentaerythritol. -Acrylate and methacrylates such as allyl alcohol and methallyl alcohol.

The emulsifier used when emulsion-polymerizing the above-mentioned unsaturated monomer is a general anionic or nonionic one. Among such emulsifiers, preferred are emulsifiers having a radically polymerizable unsaturated group (hereinafter referred to as "radical polymerizable emulsifiers"). The radical-polymerizable emulsifier used here usually has a radical-polymerizable unsaturated group, an anionic or nonionic hydrophilic group and a hydrophobic group. Examples of the radically polymerizable unsaturated group include an allyl group, a propenyl group, an acryloyl group, a methacryloyl group and a maleoyl group. Examples of the anionic hydrophilic group include a sulfuric acid group, a sulfonic acid group, a phosphoric acid group, and a carboxyl group,
Examples of the nonionic hydrophilic group include a polyoxyethylene group. Further, the hydrophobic group has 6 to 6 carbon atoms.
Examples thereof include an alkyl group of 0, an alkenyl group, an aralkyl group, an alkylaryl group and an aryl group.

Specific examples of such radically polymerizable emulsifiers include the following.

The one represented by the following general formula.

[0033]

Embedded image

(In the general formula, R ¹ is a hydrogen atom or a methyl group, R ² is an optionally substituted hydrocarbon group or an organic group having an oxyalkylene group, and A is a carbon atom having 2 to 2 carbon atoms. 4 represents an alkylene group, n represents an integer of 0 or more, and M represents an alkali metal, an alkaline earth metal, ammonium, an organic amine base or an organic quaternary ammonium base.) As such a radical polymerizable emulsifier, For example, "Eleminol JS-2" (trade name) manufactured by Sanyo Kasei Co., Ltd. may be mentioned.

Those represented by the following general formula.

[0036]

Embedded image

(In the general formula, R ¹ is a hydrocarbon group which may have a substituent, R ² is a hydrogen atom or a methyl group,
A is an alkylene group having 2 to 4 carbon atoms, and n is 0 to 100
And M represents a monovalent or divalent cation group. As such a radical-polymerizable emulsifier, for example, "Latemul S-180" (trade name) manufactured by Kao Co., Ltd. may be mentioned.

Those represented by the following general formula.

[0039]

Embedded image

(In the general formula, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrocarbon group having 8 to 24 carbon atoms or an acyl group, A is an alkylene group having 2 to 4 carbon atoms, and n is n. Is 0
˜100, m is an integer of 0 to 50, and M is a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine base. As such a radical-polymerizable emulsifier, for example, "Adekaria Soap SE-10" manufactured by Asahi Denka Co., Ltd.
“N” (trade name) is included.

Those represented by the following general formula.

[0042]

Embedded image

(In the general formula, R ¹ is an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ² is hydrogen or an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, R ³ is hydrogen or a propenyl group, A is an alkylene group having 2 to 4 carbon atoms, and n is 1
˜200, M represents an alkali metal, ammonium or alkanolamine residue, respectively. ) As such a radically polymerizable emulsifier, for example, "Aqualon HS-10" (trade name) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. may be mentioned.

Those represented by the following general formula.

[0045]

Embedded image

(In the general formula, R ¹ and R ² represent a hydrogen atom or an alkyl group having 1 to 25 carbon atoms, and R ³ and R ⁴ represent an alkyl group having 1 to 25 carbon atoms, a benzyl group or a styrene group. , M is an integer of 0 to 2, R ⁵ is a hydrogen atom or a methyl group, A is an alkylene group having 2 or 3 carbon atoms, n is an integer of 1 or more, and M is an alkali metal or an alkaline earth metal. , Ammonium or amine cation group.) Examples of such a radically polymerizable emulsifier include “Antox MS-60” (trade name) manufactured by Nippon Emulsifier Co., Ltd.

Those represented by the following general formula.

[0048]

[Chemical 6]

(In the general formula, R is a hydrocarbon group, A is an alkylene group having 2 or 3 carbon atoms, n is an integer of 1 or more, and M is an alkali metal, alkaline earth metal, ammonium or amine cation. Examples of such radically polymerizable emulsifiers include “RA-1120” (trade name) manufactured by Nippon Emulsifier Co., Ltd.

Those represented by the following general formula.

[0051]

Embedded image

(In the general formula, R ¹ is a hydrogen atom or a methyl group, R ² is a hydrocarbon group or an acyl group having 8 to 24 carbon atoms, A is an alkylene group having 2 to 4 carbon atoms, and n is n. Is 0
˜100, m represents an integer of 0 to 50, respectively. ) As such a radically polymerizable emulsifier, for example, "Adekaria Soap NE-30" manufactured by Asahi Denka Co., Ltd.
(Product name).

Those represented by the following general formula.

[0054]

Embedded image

(In the general formula, R ¹ is an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms, and R ² is a hydrogen atom or an alkyl group, alkenyl group or aralkyl group having 6 to 18 carbon atoms. , R ³ is hydrogen or a propenyl group, A is an alkylene group having 2 to 4 carbon atoms, n
Represents an integer of 1 to 200, respectively. ) Examples of such radically polymerizable emulsifiers include "Aqualon RN-50" and "Aqualon RN-30" (both are trade names) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

Those represented by the following general formula.

[0057]

Embedded image

(In the general formula, R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrocarbon group, A represents an alkylene group having 2 or 3 carbon atoms, and n represents an integer of 1 to 100. ) Examples of such a radical-polymerizable emulsifier include "RMA-506" (trade name) manufactured by Nippon Emulsifier Co., Ltd.

When emulsion-polymerizing the above-mentioned unsaturated monomer using the above-mentioned emulsifier, it is preferable to use 0.1-10% by weight of the emulsifier with respect to the total amount of the unsaturated monomers.
If the amount of the emulsifier used is less than 0.1% by weight, the polymerization may not proceed or a large amount of aggregate may be generated after the polymerization. On the other hand, if it exceeds 10% by weight, the hardness and water resistance of the overcoat layer 3 may deteriorate, and the overcoat layer 3 may be easily whitened.

A polymerization initiator is usually used in the emulsion polymerization. Examples of the polymerization initiator that can be used here include persulfate-based initiators, redox-based initiators, and water-soluble azo compounds. The amount of the polymerization initiator used is usually 0.1 to the total amount of unsaturated monomers.
It is preferably set to 3% by weight.

Specific examples of the polymerization initiator include potassium persulfate, potassium persulfate / sodium hydrogen sulfite, hydrogen peroxide / ascorbic acid, t-butyl hydroperoxide / Rongalit, ACVA manufactured by Otsuka Chemical Co., Ltd.
(4,4'-azobis- (4-cyanovaleric acid) neutralized with a tertiary amine and solubilized), VA-086 (2,2'-azobis [, manufactured by Wako Pure Chemical Industries, Ltd. 2-Methyl-N- (2-hydroxyethyl) propionamide]) and the like.

When it is necessary to adjust the degree of polymerization during emulsion polymerization, a chain transfer agent typified by mercaptans can be used. Examples of the chain transfer agent include lauryl mercaptan and octyl thioglycolate.

As the emulsion polymerization method, a general emulsion polymerization operation can be adopted. For example, the nonvolatile content is 40
It can be carried out by adopting a pre-emulsion dropping method or a monomer dropping method so that the weight percentage is not less than, and setting the polymerization temperature and the polymerization time to 40 to 100 ° C. and 1 to 8 hours, respectively.

The acrylic emulsion contained in the above-mentioned aqueous room-temperature-curable resin composition used for forming the overcoat layer 3 is an acrylic emulsion obtained by the above-mentioned emulsion polymerization and having a group capable of reacting with an isocyanate group. Is. As such an acrylic emulsion, those having an acid value of resin solid content of 5 or less are particularly preferable.
When the acid value is more than 5, the amount of base used for neutralizing the acrylic emulsion is increased, the pot life of the aqueous room temperature curable resin composition is shortened, and the hydrophilicity of the acrylic emulsion resin is increased. Therefore, whitening of the overcoat layer 3 may occur easily.

The above-mentioned resin solid content acid value is usually based on the acidic group introduced by the unsaturated monomer containing an acidic group used in the production of an acrylic emulsion.
This acidic group is preferably neutralized with an alkali metal, a quaternary ammonium hydroxide, a tertiary amine or the like.
Neutralization with ammonia is not preferable because ammonia reacts with isocyanate groups.

The hydroxyl value of the resin solid content of the acrylic emulsion is preferably 20 to 200, and 40 to 1
60 is more preferred. Incidentally, the hydroxyl group which becomes such a hydroxyl group is, for example, one introduced by the above-mentioned unsaturated monomer containing a hydroxyl group. When the hydroxyl value is less than 20, the degree of crosslinking of the overcoat layer 3 may be insufficient and the overcoat layer 3 may not exhibit the required coating film properties. On the other hand, when the hydroxyl value exceeds 200, emulsion polymerization, which is a production process of the acrylic emulsion, may be difficult, and an acrylic emulsion having a practical concentration may not be obtained.

The polyisocyanate used in the aqueous room temperature curable resin composition for forming the overcoat layer 3 is a self-emulsifying type polyisocyanate. Examples of such a polyisocyanate include those obtained by reacting a part of the isocyanate groups of an aliphatic or alicyclic polyisocyanate and its derivative with a polyethylene oxide monoalkyl ether to impart water dispersibility.

Here, as the aliphatic or alicyclic polyisocyanate, hexamethylene diisocyanate containing isocyanurate group, uretdione group, urethane group, allophanate group, biuret group and / or oxadian group or isophorone diisocyanate is used. To be A desired self-emulsifying polyisocyanate can be prepared by reacting a part of the isocyanate groups of these isocyanate compounds and their derivatives with a polyethylene glycol monoalkyl ether represented by the following formula.

[0069]

Embedded image

Specific examples of such a self-emulsifying polyisocyanate include trade name "DC-3900" (NCO group content = 17% by weight) manufactured by Nippon Polyurethane Co., Ltd. and trade name "DC-3901" manufactured by the same company. (NCO group content = 13% by weight) and trade name “Baihijuru TPLS-2032” manufactured by Sumitomo Bayer Urethane Co., Ltd.
(NCO group content = 17% by weight) and the like.

When the polyisocyanate used is not hydrophilized, the appearance of the topcoat layer 3 may be impaired in terms of transparency, etc., since it has a low affinity for the acrylic emulsion.

The aqueous room temperature curable resin composition for forming the overcoat layer 3 can be prepared by mixing the above acrylic emulsion and the above polyisocyanate. Such an aqueous room temperature curable resin composition,
It may be used as a clear paint as it is, or may be used by adding a matting agent, a coloring powder, a glittering material and the like. In the latter case, the overcoat layer 3 can further enhance the designability of the designable coating film 1 together with the designable coating film base layer 2.
Examples of the glitter material include metal powder and mica.

The mixing method of both components is not particularly limited, but for example, an acrylic emulsion coating composition to which various additives such as an ultraviolet absorber, a light stabilizer and a thickener are added in advance if necessary. It is possible to employ a method of preparing and then adding a polyisocyanate that has been emulsified and dispersed in water in advance, a method of directly adding the polyisocyanate to an acrylic emulsion or an acrylic emulsion coating material, and stirring and dispersing.

The mixing ratio of the above acrylic emulsion and the above polyisocyanate is (groups capable of reacting with isocyanate groups contained in the acrylic emulsion):
The molar ratio of (NCO group in polyisocyanate) is 1:
It is preferable to set it to about 5 to 5: 1. When the number of the groups capable of reacting with the isocyanate group is less than this, the drying property and water resistance of the overcoat layer 3 may decrease. On the other hand, when the number of the groups capable of reacting with the isocyanate group is more than this, the degree of crosslinking of the overcoat layer 3 may be insufficient, and the desired properties of the overcoat layer 3 may not be obtained.

The overcoat layer 3 is prepared by adjusting the above-mentioned aqueous room temperature curable resin composition to a desired viscosity, and applying this to a brush coating, for example.
It can be formed by applying it on the decorative coating film base layer 2 by a general coating method such as spray coating or roll coater coating and drying at room temperature or forced drying.

The thickness of the overcoat layer 3 is usually 20 to 60 μm.
It is preferable to set If the thickness is less than 20 μm, the protective function of the decorative coating film base layer 2 may be lost. vice versa,
If it exceeds 60 μm, poor drying, sagging, flow, etc. may occur and the appearance may be impaired.

Method for Forming Decorative Coating Film In the case of forming the above-mentioned decorative coating film 1, the above-mentioned decorative coating base layer 2 is formed on a substrate, and the above-mentioned decorative coating base layer 2 is formed on the above-mentioned decorative coating base layer 2. The topcoat layer 3 is formed. The substrate to which this method is applied is, for example, concrete, mortar, ALC.
Materials used as general building materials such as, and materials having shape-retaining properties such as aluminum, aluminum alloys, stainless steel, and copper.

When the base material is concrete, mortar, ALC, or the like, a primer as a base treatment agent is applied beforehand as needed, and then the decorative coating base layer 2 is formed. The method for forming the decorative coating base layer 2 and the overcoat layer 3 is as follows.
As described above.

According to such a method for forming a decorative coating film, the decorative coating film can be directly formed on the outer wall or the inner wall of the building depending on the type of the substrate to be applied, or as will be described later. It is possible to manufacture a decorative board that does.

Decorative Plate FIG. 2 is a vertical sectional view of one form of the decorative plate according to the present invention. In the figure, a decorative plate 10 has a rectangular plate shape and mainly includes a substrate 11 and a design coating film 12 arranged on the substrate 11. The size of the decorative plate 10 is, for example, 9
It is set to 00 × 600 mm or 600 × 450 mm.

The substrate 11 is a plate-shaped member made of a material having a shape-retaining property such as aluminum, aluminum alloy, stainless steel, and copper, and usually has a thickness of 0.13 to 0.
It is set to 3 mm. When the thickness is less than 0.13 mm, the strength of the decorative plate 1 is lowered and the bending is increased, so that the workability may be lowered. On the other hand, if the thickness exceeds 0.3 mm, it becomes difficult to cut into a desired size during construction. A preferable material for the substrate 11 is aluminum, which has good workability such as cutting property during construction, adhesion, and durability.

The decorative coating film 12 has the same structure as that of the above-mentioned decorative coating film 1, and includes the same decorative coating film base layer 13 and the same top coat layer 14.

The decorative plate 10 as described above is provided with the substrate 11
A base coat layer may be further provided between and the design coating film 12. The base coat layer is for protecting the substrate 11, and is usually made of an epoxy resin. The thickness of such a base coat layer is preferably set to 5 to 15 μm.

Such a decorative board 10 can be attached to the outer wall surface or the inner wall surface of a building by using cement, an adhesive, or the like, for example, to give the outer wall surface or the inner wall surface a design property.

The design coating film 1 and the decorative plate 10 described above are
Since the overcoat layers 3 and 14 are formed by using the above-mentioned aqueous room-temperature-curable resin composition, the overcoat layers 3 and 14 are unlikely to be whitened even when exposed to sunlight, rainwater, or the like. Therefore, the designable coating film 1 and the decorative board 10 can maintain good designability for a long period of time.

[0086]

EXAMPLES Production Example A glass 3 liter flask equipped with a stirrer, a temperature controller, a dropping funnel and a nitrogen introducing tube was charged with 3 g of "Antox MS-60" (90% of active ingredient) as a radical polymerizable emulsifier. "Aqualon RN-50" (Active ingredient 6
5%) 8 g and an aqueous emulsifier solution prepared by dissolving 343 g of deionized water were prepared and heated to 83 ° C. under a nitrogen atmosphere. To this, 300 g of styrene, 260 of methyl methacrylate
g, 240 g of 2-ethylhexyl acrylate and 200 g of 4-hydroxybutyl acrylate, and 50 g out of 1,000 g of a monomer mixture. Thereafter, 300 g of deionized water was added to 10 g of a polymerization initiator "ACVA" (active ingredient 80%) manufactured by Otsuka Chemical Co., Ltd., and 1/4 amount of the initiator aqueous solution neutralized and dissolved with 5 g of dimethylethanolamine was added. In addition, the polymerization was started.

After 10 minutes from the addition of the initiator, 19 g of "Antox MS-60" as a radically polymerizable emulsifier and 23 g of "Aqualon RN-50" were added to 600 ml of deionized water.
A monomer emulsion obtained by adding the remaining 950 g of the above-mentioned monomer mixture to an emulsifier aqueous solution dissolved in g with stirring and dropping the mixture is added dropwise over 120 minutes, and together with this, the remaining 3/4 amount of the aqueous initiator solution. 1
It dripped uniformly over 40 minutes. After completion of the dropwise addition, stirring was continued while maintaining the same temperature for 120 minutes to complete the reaction. After cooling, the acrylic emulsion obtained by filtering through a 400-mesh wire net had a hydroxyl value of 79, an acid value of 0, a resin solid content of 45%, and a pH of 6.3.

2% by weight of TINUVIN 1130 (UV absorber manufactured by Ciba-Geigy Co., Ltd.) and 1% by weight of SANOL LS2 were added to the acrylic emulsion thus obtained.
92 (light stabilizer made by Sankyo Co., Ltd.) was added.

Next, the hydrophilic polyisocyanate "DC-
To 30 g of "3900", 30 g of deionized water was added little by little with stirring to obtain an aqueous dispersion having a solid content of 50%. This aqueous dispersion is immediately added to the acrylic emulsion 222 described above.
By adding to g, an aqueous room temperature curable resin composition (clear coating) was obtained.

Example A rust-preventive aluminum plate was prepared, and a design paint (“Jiquitone” manufactured by Nippon Paint Co., Ltd.) was used so that the base coat layer and the design coating film base layer had a total thickness of 3 to 5 mm. ) Was coated and dried at room temperature for 24 hours.

Next, the clear coating material obtained in the Production Example was applied on the obtained design coating film base layer so as to have a content of 0.2 to 0.3 kg / m ² and dried at room temperature for 7 days to obtain a design characteristic. A decorative board having a design coating film having a coating film base layer and a clear layer was obtained.

[0092]Comparative Example 1  A commercially available silicone resin paint was used as a clear paint.
A decorative board was obtained in the same manner as in Example except for the above points.

Comparative Example 2 A decorative board was obtained in the same manner as in Example except that a commercially available acrylic urethane resin paint was used as the clear paint.

Regarding the decorative boards obtained in the evaluation examples and the comparative examples 1 and 2,
The initial coating property, secondary adhesion property, impact resistance, alkali resistance, water resistance, freeze-thaw property and accelerated weathering resistance of the design coating film were evaluated. The evaluation method is as follows. Table 1 shows the results.

(Initial Adhesion) Evaluation was performed according to JIS A 6910. (Secondary Adhesion) A decorative board that was subjected to a water resistance test described below was evaluated according to JIS A 6910. (Impact resistance) According to JIS K 5400 8.3.2 DuPont type, 500 gl / 2i with respect to the design coating film
The impact was evaluated by applying an impact of n. (Alkali resistance) The state of the coating film surface after being immersed in a saturated aqueous solution of calcium hydroxide for 30 days was visually determined.
The criteria are as follows. ：: No abnormality. Δ: The clear coating layer is whitened.

(Water resistance) The state of the coating film surface after being immersed in water for 30 days was visually evaluated. The criterion is the same as in the case of alkali resistance. (Freeze-thaw) 3 according to ASTM C 666-75
A test of 00 cycles was performed, and the state of the coating film surface was visually determined. The criterion is the same as in the case of alkali resistance. (Accelerated weather resistance) A 1000-hour test was performed using a sunshine weatherometer, and the state of the coating film surface was visually determined. The criterion is the same as in the case of alkali resistance.

[0097]

[Table 1]

[0098]

EFFECTS OF THE INVENTION The designable coating film according to the present invention has the topcoat layer formed by using the above-mentioned aqueous room temperature curable resin composition. The designability expressed by the base layer is not easily impaired.

In the method for forming a decorative coating film according to the present invention,
Since the topcoat layer is formed using the above-mentioned aqueous room temperature curable resin composition, it is possible to realize a design coating film in which the designability expressed by the design coating film base layer is not easily impaired by whitening of the topcoat layer. it can.

Since the decorative board according to the present invention is provided with the above-mentioned decorative coating film, the overcoat layer is unlikely to cause whitening,
Designability The designability expressed by the base layer of the coating film is unlikely to be impaired.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a decorative coating film according to one embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a decorative plate according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Design coating film 2 Design coating film base layer 3 Topcoat layer 10 Decorative board 11 Substrate 12 Design coating film 13 Design coating film base layer 14 Top coating layer

Claims (9)

[Claims] 1. A design coating film base layer, and an overcoat layer disposed on the design coating film base layer, wherein the top coating layer has a group capable of reacting with an isocyanate group and is obtained by emulsion polymerization. A decorative coating film formed using an aqueous room temperature curable resin composition containing an acrylic emulsion and a self-emulsifying polyisocyanate. 2. The designable coating film according to claim 1, wherein the acrylic emulsion has a resin solid content hydroxyl value of 20 to 200. 3. The decorative coating film according to claim 1, wherein the acrylic emulsion has a resin solid content acid value of 5 or less. 4. The decorative coating film according to claim 1, wherein the acrylic emulsion is emulsion-polymerized by using an emulsifier having a radically polymerizable unsaturated group. 5. The emulsifier has a hydrophilic group and a hydrophobic group in addition to the radically polymerizable unsaturated group, and the radically polymerizable unsaturated group is an allyl group, a propenyl group, an acryloyl group, a methacryloyl group and a maleoyl group. The hydrophobic group is at least one selected from the group consisting of a sulfuric acid group, a sulfonic acid group, a phosphoric acid group, a carboxyl group and a polyoxyethylene group, and 5. The group is at least one selected from the group consisting of an alkyl group having 6 to 60 carbon atoms, an alkenyl group, an aralkyl group, an alkylaryl group, an aryl group and a hydrocarbon group having a side chain thereof.
Designed coating film described in. 6. A polyisocyanate in which the self-emulsifying polyisocyanate is water-dispersible by reacting a part of the isocyanate groups of an aliphatic or alicyclic polyisocyanate and its derivative with a polyethylene oxide monoalkyl ether. The design coating film according to claim 1, 2, 3, 4, or 5. 7. A step of forming a decorative coating film base layer on a substrate, and a step of forming an overcoat layer on the decorative coating film base layer, wherein the overcoat layer is a group capable of reacting with an isocyanate group. A method for forming a decorative coating film, which is formed by using an aqueous room-temperature-curable resin composition containing an acrylic emulsion obtained by emulsion polymerization and containing a self-emulsifying polyisocyanate. 8. A shape-retaining substrate, a design coating film base layer provided on the substrate, and an overcoat layer arranged on the design coating film base layer, wherein the top coating layer is an isocyanate. A decorative board formed using an aqueous room temperature curable resin composition containing an acrylic emulsion having a group capable of reacting with a group and obtained by emulsion polymerization, and a self-emulsifying polyisocyanate. 9. The decorative board according to claim 8, wherein the substrate is an aluminum plate.