JPH10273608A - Coating of porous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roll coating method of a water-based coating to a porous material as timber, particularly improve the smoothness of the coated layer. SOLUTION: When a porous material is roll-coated with a water-based coating, a composition containing a polymerizable unsaturated monomer with a molecular weight of <=3,000, colorants, a photosensitizer and water as main components is used as a water-based coating material to effect roll coating, the coated layer is cured by irradiation with ultraviolet rays and the cured layer is coated with a clear coating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for roll-coating a water-based paint on a porous material such as wood, and more particularly to improving the smoothness of a paint film.

[0002]

2. Description of the Related Art Conventionally, in order to make use of a wood grain pattern of a wood, a pipe portion (wood grain, perforated portion) is filled with a coloring agent and further coated with a transparent paint.

[0003] However, a colorant containing an organic solvent as a solvent or a dispersion medium is used as the colorant, which is not preferable from the viewpoints of pollution prevention, resource saving and danger prevention. It takes a long time (generally several hours or more at room temperature), and further has a defect that the colorant migrates to the upper transparent coating film and bleeding is easily generated.

An aqueous colorant has been proposed to solve these defects. Specific examples include a polymerizable unsaturated resin, a monomer having a polymerizable unsaturated double bond, a photosensitizer, and an aqueous colorant obtained by dispersing or dissolving a color pigment or dye in water. Is suitable from the viewpoints of pollution prevention, resource saving and danger prevention, and has the effect of shortening the drying time and preventing bleeding even when a transparent paint is applied. However, when this aqueous colorant is roll-coated on a porous material, there is a defect that the filling of the conduit portion is insufficient, a streak-like pattern is easily generated, and the smoothness is poor.

[0005]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned deficiencies in the roller coating of a porous material with an aqueous colorant. The feature of the present invention is that the polymerizable unsaturated resin is used as an aqueous colorant. The above defects are all eliminated by using a polymerizable unsaturated monomer having a molecular weight of 3000 or less, a colorant, a photosensitizer, and an aqueous paint containing water as a main component. Cleaning of the roll coating machine at the time became easier.

[0006] That is, the present invention relates to: 1) roll coating an aqueous paint on a porous material;
A coating method for a porous material, characterized by using a composition containing a polymerizable unsaturated monomer having a molecular weight of 3000 or less, a colorant, a photosensitizer, and water as main components,
And 2: Roll-coating a porous material with a water-based coating mainly composed of a polymerizable unsaturated monomer having a molecular weight of 3000 or less, a colorant, a photosensitizer and water, and curing by irradiation with ultraviolet rays. Thereafter, the present invention relates to a method for coating a porous material, which further comprises applying a clear paint.

The porous material (substrate to be coated) applicable in the present invention only needs to have a porous surface at least, and it does not matter whether the interior is porous. The diameter of the pores in the porous part is about 5 mm or less, especially about 1 mm or less. As such a porous material, besides a wooden material,
And inorganic materials such as concrete blocks and cement products, and foamed plastic materials.
The shape of the porous material is not particularly limited as long as roll coating is possible. For example, a plate shape and a sheet shape are preferable.
There may be no irregularities such as grooves on the surface. It is preferable that the surfaces of these materials are polished or surface-treated before painting. In particular, the method of the present invention is preferably applied to wood used for building materials, furniture furniture and decorative articles.

The water-based paint used in the present invention has a molecular weight of 3
A colored liquid composition having a polymerizable unsaturated monomer of 000 or less, a colorant, a photosensitizer and water as main components, and a polymerizable unsaturated resin having a molecular weight of 3000 or more is substantially not contained. .

The polymerizable unsaturated monomer has at least one polymerizable unsaturated double bond in one molecule and has a molecular weight of 300.
0 or less, for example, methyl acrylate
, Methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, hexyl acrylate, hexyl methacrylate
Octyl acrylate, octyl methacrylate,
Lauryl acrylate, lauryl methacrylate, 2-
(Meth) acrylic acid such as ethylhexyl acrylate, 2-ethylhexyl methacrylate and the like having 1 to 22 carbon atoms
A monoester of a monohydric alcohol with a glycol having 2 to 20 carbon atoms such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and hydroxybutyl (meth) acrylate; Monoesters of (meth) acrylic acid; (meth) acrylic acid such as methoxybutyl acrylate, methoxybutyl methacrylate, methoxyethyl acrylate, methoxyethyl methacrylate and C2-C2 Alkoxy ester with 18, N, N-dimethylaminoethyl acrylate,
N, N-dimethylaminoethyl methacrylate, N, N
-Diethylaminoethyl acrylate, N, N-diethylaminoethyl methacrylate, Nt-butylaminoethyl acrylate, Nt-butylaminoethyl methacrylate, N, N-dimethylaminopropyl Aminoacrylic monomers such as acrylate and N, N-dimethylaminopropyl methacrylate; acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-ethylacrylamide, N-ethylmethacryl Amide, N-butylacrylamide, N
-Acrylamide monomers such as -butylmethacrylamide, N-dimethylacrylamide, N-dimethylmethacrylamide; monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, itaconic acid, fumaric acid, mesaconic acid and anhydrides thereof Carboxyl group-containing monomers such as dicarboxylic acids and modified products thereof, such as glycidyl acrylate and glycidyl methacrylate; styrene,
α-methylstyrene, vinyltoluene, acrylonitrile, vinyl acetate, vinyl chloride and the like. Furthermore, a polyhydric alcohol such as ethylene glycol, polyethylene glycol, propylene glycol, or polypropylene glycol is reacted with (meth) acrylic acid or the like to obtain two or more polymerizable molecules in one molecule. A monomer having an unsaturated double bond can also be suitably used.

Further, an unsaturated polyester resin; a (meth) acrylic acid or a hydroxyalkyl (meth) acrylate or the like is added to a polyester resin or an acrylic resin directly or via a polyisocyanate to polymerize the terminal or side chain. Resin with unsaturated unsaturated double bond introduced; (meth) acrylic acid or hydroxyalkyl (meth) acrylate added to urethane-modified acrylic resin or polyester resin and polymerized to terminal or side chain An unsaturated resin having a polymerizable unsaturated double bond introduced into a terminal or a side chain of an epoxy resin;
Unsaturated resins of one or more kinds and having a molecular weight (number average molecular weight) of 3000 or less can also be used as the polymerizable unsaturated monomer.

If the molecular weight of the polymerizable unsaturated monomer is more than 3,000, the filling of the porous material into the conduit portion is insufficient, and streak-like patterns are liable to occur, which is not preferable.

The coloring agent imparts a color tone to the coating film of the water-based paint, and includes, for example, titanium oxide, iron oxide, zinc white,
Inorganic pigments such as carbon black, cadmium red, molybdenum red, chrome ero, chromium oxide, Prussian bull, and cobalt bull; organic such as azo pigments, phthalocyanine pigments, quinacridone pigments, isoindoline pigments, sulene pigments and perylene pigments Pigment; metallic pigments such as flaky aluminum, mica, mica surface-coated with a metal oxide, and mica-like iron oxide; and dyes.

Photosensitizers are useful for curing a coating film of the water-based paint by light irradiation, for example, 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 4-tert-butyl-trichloro. Acetophenone, diethoxyacetophenone, 2-hydroxy-
2-methyl-1-phenylpropan-1-one (manufactured by Merck, trade name, "Darocur-1173"), 1- (4
-Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl)-
2-hydroxy-2-methylpropan 1-one, 4-
Acetophenones such as (2-hydroxyethoxy) -phenyl (2-hydroxy-2-propyl) ketone and 1-hydroxycyclohexyl phenyl ketone (trade name, “Irgacure-184”, manufactured by Ciba-Geigy Co.); benzoin, benzoin methyle Benzoin compounds such as ter, benzoin ethyl ether, benzoin propyl ether, benzoin isobutyl ether, and benzyl dimethyl ketal (trade name, “Irgacure 651”, manufactured by Ciba-Geigy Corporation); benzophenone, benzoyl benzoic Acid, methyl benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-
Benzophenones such as 4'-methyldiphenyl sulfide and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone,
Thioxanthones such as methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, and 2,4-dichlorothioxanthone; α-acyloxime esters, acylphosphine oxides, methylphenylglyoxylate, benzyl , 9,10-phenanthrenequinone, camphor-quinone, dibenzosuberone,
2-ethylanthraquinone, 4 ', 4 "-diethylisophthalophenone, 3,3', 4,4'-tetra (t-
Special groups such as butyl peroxycarbonyl) benzophenone.

The aqueous paint used in the present invention can be prepared by dispersing or dissolving the above-mentioned polymerizable unsaturated monomer, colorant and photosensitizer in water.

The composition ratio of each of these components can be arbitrarily selected depending on the purpose of application, but the colorant is 5 to 200 parts by weight and the photosensitizer is 0.1 to 100 parts by weight of the polymerizable unsaturated monomer.
1 to 10 parts by weight is preferred. Further, a pigment dispersant, an extender, an antisettling agent, and the like can be added to the water-based paint as needed.

In the present invention, the aqueous paint is roll-coated on a porous material. The solid content at the time of painting is 40-6
0% by weight, viscosity: 5-20 seconds / Zerncup # 5/20
It is preferable that the temperature is included in the range of ° C.

Examples of the roll coating machine for applying the water-based paint include ordinary sponge, urethane rubber (non-foaming) or iron natural coater and iron reverse coater. Can be used.

Specifically, first, a water-based paint is applied to the surface of the porous material with a natural coater, and then the water-based paint is pressed into the pores of the material with a reverse coater while it is not yet cured. In this way, the water-based paint adhering to the material surface is wiped. As a result, the inside of the pores of the porous material is filled with the water-based paint, the portion is colored, and the other surface is hardly or not coated with the water-based paint, so that the pattern such as grain becomes clear. The amount of the water-based paint to be applied can be arbitrarily selected depending on the purpose, but usually, the range of 0.2 to 4 g per square meter of the paint is suitable.

As a wiping method, besides the above-mentioned reverse roll coater, brush wiping (wiping machine), manual wiping (wiping with a rag), cloth belt wiping, or the like can be used.

In order to cure the aqueous paint or the like filled in the pores of the porous material, the coated surface is irradiated with ultraviolet rays.
Specifically, a mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a xenon lamp, a carbon arc, a metal halide lamp, sunlight, or the like is used as an irradiation source, and it is usually 10 to 2000 mJ in air or an inert gas. When the irradiation is performed with an ultraviolet irradiation amount of / cm ² , the water-based paint filled in the pores is rapidly crosslinked and cured, and the object of the present invention can be achieved.

The method of the present invention is characterized in that the porous material is roll-coated with an aqueous paint as described above, filled in the pores, cured by irradiating ultraviolet rays, and then coated with a clear paint. And a method for coating a porous material.

[0022] The clear paint is an organic solvent and / or
Water is used as a solvent or a dispersion medium. For example, a room temperature-curable, heat-curable, or ultraviolet irradiation-curable paint containing acrylic resin, polyester resin or the like as a main component can be used. The coating amount of the clear paint is preferably 1 to 20 g, particularly preferably 4 to 10 g per square meter.

[0023]

【The invention's effect】

1. By applying a water-based paint to a porous material such as wood by roll coating, it has become possible to apply a smooth surface free of uneven streaks.

2. The water-based paint filled in the inside of the hole hardly oozes into the clear coating film applied on the surface.

3. Since the water-based paint used in the present invention uses water as a solvent or a dispersion medium, it is a non-hazardous substance with little danger, and is preferable from the viewpoint of preventing pollution and saving resources.

4. After filling with the water-based paint, it can be immediately cured by irradiation with ultraviolet rays without being left at room temperature, so that the process is greatly shortened.

5. Since it contains little or no organic solvent, there is no organic solvent odor.

[0028]

【Example】

1. Preparation of water-based paint (1) Polyethylene glycol diacrylate (molecular weight 40
0) 100 parts by weight, 3.5 parts by weight of carbon black, 4 parts by weight of a red pigment [Fuji Fast Red 7R # 3300 (trade name, manufactured by Fuji Dye Co., Ltd.)], and a yellow pigment [Novata Muero-HR (Hoechst) 6 parts by weight) and 5 parts by weight of a photosensitizer [Darcure 1173 (trade name, manufactured by Ciba Geigy)] were mixed and dispersed in water to obtain a solid content of 50% by weight at the time of coating. The viscosity was adjusted to 10 seconds / Zancup # 5/20 ° C.

2. Preparation of water-based paint (2) (for comparison) 100 parts by weight of unsaturated polyester resin (molecular weight 4000), 3.5 parts by weight of carbon black, red pigment [Fuji Fast Red 7R # 3300 (trade name, manufactured by Fuji Dye Co., Ltd.) )], 6 parts by weight of a yellow pigment [Novata-Muelo-HR (trade name, manufactured by Hoechst)] and 5 parts by weight of a photosensitizer [Darcure 1173 (trade name, manufactured by Ciba Geigy)] are mixed with water. Disperse the solids content at coating
0% by weight, and the viscosity was adjusted to 10 seconds / Zerncup # 5/20 ° C.

2. Example 1 An aqueous coating material (1) was sprinkled with a natural roll coater made of sponge at a room temperature of 0.4 to 0.4 mm per square meter on a oak plywood flooring material polished with sand paper of # 200 to # 320 at room temperature. After coating with a coating amount of 0.6 g, the water-based paint (1) was filled into the holes of the material with a reverse coater while the material was not yet cured, and was filled while adhering to the surface. Wiping the water-based paint that is present. Then, it is immediately irradiated with a high-pressure mercury lamp at an irradiation amount of 170 to 210 mJ / cm ² to crosslink and cure the water-based paint filled in the inside of the hole. Then, an unsaturated polyester resin clear paint is applied at a coating amount of 2.5 to 3 g per square meter, and irradiated with a high-pressure mercury lamp at an irradiation amount of 260 to 320 mJ / cm ² to crosslink the clear coating film. It was cured.
The plywood painted in this way is the introduction pipe (wood grain part)
It is clear, has no uneven streaks, has excellent smoothness, and the water-based paint filled in the pores hardly oozes into the clear coating film, and it can be cured by ultraviolet irradiation immediately after filling the water-based paint. As a result, the process can be shortened.

3. Comparative Example 1 The coating was performed in the same manner as in Example 1 except that the water-based coating (1) in Example 1 was replaced with the water-based coating (2). As a result, the introduction pipe portion was unclear, uneven streaks were noticeable, the smoothness was not sufficient, and the water-based paint filled in the pores bleed into the clear coating film.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 5/00 C09D 5/00 C (72) Inventor Toyoichi Shimizu 33-1, Kanzakicho, Amagasaki-shi, Hyogo Kansai Paint Co., Ltd.

Claims (2)

[Claims] When a water-based paint is roll-coated on a porous material, the water-based paint mainly contains a polymerizable unsaturated monomer having a molecular weight of 3000 or less, a coloring agent, a photosensitizer and water. A coating method for a porous material, characterized by using a composition to be used. 2. A porous material is roll-coated with a water-based coating mainly composed of a polymerizable unsaturated monomer having a molecular weight of 3000 or less, a colorant, a photosensitizer and water, and irradiated with ultraviolet rays. A method of coating a porous material, which comprises curing and then applying a clear paint.