JPH11228256A - Painted cement board - Google Patents

Abstract

(57) [Problem] To provide a coated cement board capable of preventing peeling of a base material while improving appearance quality and weather resistance. SOLUTION: A synthetic resin latex-based sealer 14a is applied to a surface 13a of a hard wood chip cement plate 13 containing finely divided wood material 12 to form a peel preventing layer 14, and a top of the peel preventing layer 14 is formed. Paints 15a and 16
a and undercoat film layers 15, 1 formed by applying a
6 are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a painted cement board which is mainly used for an outer wall of a building and has both decorativeness and weather resistance.

[0002]

2. Description of the Related Art As a conventional coated cement plate of this type, as shown in FIG. 3, a ceramic substrate 1a such as a hard cement plate 1 is protected from erosion by wind, rain, light and heat.
In order to give a desired color or luster to decorate the appearance, there is known a method in which a coating material 2a is applied to form a coating film 2 (see Japanese Patent Application Laid-Open No. 4-104868).

[0003] In such a case, a plurality of coating films having different functions are formed. In general, the coating layer in contact with the hard cement board 1 as the base material is a coating film having a property of enhancing adhesion to the base material surface 1a, and the intermediate layer is formed by giving the coating film thickness. The uppermost layer is a decorative layer that enhances the flatness of the coating film and imparts water resistance, and the uppermost layer is a decorative layer that imparts color and gloss, and resists erosion by sunlight, wind, rain, steam, and the like. Further, in the hard cement board 1, a screw 4 screwed into a steel frame 3 disposed on the back side is inserted into a screw hole 5.

[0004]

However, in such a conventional apparatus, the hard cement plate 1 is made of a ceramic-type base material having a slightly fragile base material surface 1a, such as hard wood chip cement composed of wood powder. When the coating film is formed in multiple layers by the method described above, the adhesion between the hard cement plate 1 and the coating film 2 is certainly improved, but the surface of the substrate 1a is reduced by the amount of the wood powder contained in the substrate.
However, when an adhesion test such as peeling of the joint tape is performed, there is a problem that not only the coating film 2 but also the substrate surface 1a of the hard cement board 1 itself peels.

Accordingly, an object of the present invention is to provide a coated cement board capable of preventing peeling of a substrate while improving the appearance quality and weather resistance.

[0006]

According to the first aspect of the present invention, there is provided a hard wood chip cement board coated with a synthetic resin latex sealer to form a peel prevention layer. It is characterized by a coated cement board provided with a coating layer formed by applying a paint on the anti-peeling layer while being formed.

According to the above-mentioned structure, even if, for example, the joint sealing material stuck on the surface of the coating layer is peeled off, the coating layer remains on the surface of the peel preventing layer. The peel-preventing layer stays on the surface of the hard wood chip cement board only by peeling from the hard wood chip cement board.

[0008] For this reason, even in the case of a hard wood chip cement board containing finely divided wood material, the hard wood chip cement board itself is not likely to be peeled or broken.

Accordingly, the peeling prevention layer prevents peeling of the substrate while improving the appearance quality and weather resistance by the coating layer.

[0010] According to the second aspect of the present invention, the synthetic resin latex sealer has a particle diameter of 0.01 to 0.01.
The coated cement board according to claim 1, which is 0.3 µm.

According to the above-mentioned construction, the synthetic resin latex-based sealer of the coated cement board has a particle size of 0.01 to 0.3 μm, so that the hard wood chip cement board has a high density. And a good affinity range with the surface layer of the above.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

[0013]

Embodiment 1 Hereinafter, a specific embodiment 1 of the present invention will be described.
Will be described with reference to the drawings.

FIGS. 1 and 2 show a first embodiment of the present invention.
It shows. Note that the same or equivalent components as those of the conventional example are denoted by the same reference numerals and described.

First, the structure will be described. In the first embodiment, as shown in FIG.
Both members 11, 1 are provided on the back surfaces 11b, 11b of the members 1, 11, respectively.
A steel frame 3 is provided so as to straddle the space.

The painted cement board 11 is mainly composed of a cement board 1 as a base material including the finely divided wood materials 12.
3, a peel preventing layer 14 formed by a synthetic resin latex sealer 14a applied to the surface 13a of the cement board 13, and a coating 15a, 16a formed by applying on the surface 14b of the peel preventing layer 14 Undercoat layer 15 and overcoat layer 16.

[0017] Of these, the overcoat layers 16, 16
On the surfaces 16b, 16b of the butting portions 16c, 16c, the joint tape 17 attached by the adhesive layer 17a is provided.
Is provided between the two members 11, 11.

The cement plate 13 is composed of 50 to 96 parts by weight of Portland cement and 2 to 2 parts of alumina cement.
5 parts by weight, gypsum comprising one or both of anhydrous gypsum and hemihydrate gypsum 1.5 to 15 parts by weight, slaked lime of 10 parts by weight or less, and alkali metal salt of organic carboxylic acid 0.2 to
A mixture obtained by mixing 2.0 parts by weight is kneaded with finely divided wood material 12 and water, and the mixture is heated and pressed to produce a mixture. The organic carboxylic acid is preferably citric acid, malic acid, gluconic acid, glutaric acid, or glycolic acid, and the alkali metal salt is preferably a sodium salt or potassium salt.

The synthetic resin latex sealer 14a of the first embodiment includes acrylic resins such as polyacrylates and polymethacrylates and copolymers thereof, acrylic-styrene copolymers, acrylic-vinyl acetate copolymers. Vinyl acetate such as coalesce, acrylic-vinyl chloride copolymer, acrylic-ethylene copolymer, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-styrene copolymer Resin, polyvinyl chloride, vinyl chloride resin such as vinyl chloride-acryl copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-styrene copolymer, and vinylidene chloride resin such as polyvinylidene chloride and its copolymer And the like,
It is preferable to use an acrylic resin such as a polyacrylic acid ester or a polymethacrylic acid ester and a copolymer thereof in view of the denseness of the base material, the adhesion to the upper layer, and the resistance to strong alkali eluted from the base material.

The above synthetic resin latex sealer 14a
If the particle diameter is less than 0.01 μm, the viscosity of the paint increases and application and handling become difficult, and if it is 0.3 μm or more, the impregnating property on the surface 13 a of the cement plate 13 decreases, and the compactness and adhesion to the base material are reduced. The thickness is preferably 0.01 to 0.3 μm because the property is lowered.

The synthetic resin latex sealer 14a may use a synthetic resin component alone or may contain a pigment and other additives. Other additives include film forming aids, plasticizers, thickeners, denaturants, dispersants, wetting agents, defoamers, preservatives, antifungal agents, antifreeze agents,
Rust inhibitors and the like.

The synthetic resin-based latex sealer 14a
Is applied to the surface 13a of the cement plate 13 by spray coating such as air spray, cold spray, hot spray, airless spray, or aerosol spray, roller coating, rolling coating such as tumbling,
Flow coating, shower coating, etc., coating using electrical properties such as electrostatic coating, electrodeposition coating, powder coating, dipping, vacuum press coating, ironing, powder spray coating, brush coating, spatula coating However, as a coating method for forming a uniform coating film on an uneven cement substrate, spray coating, electrostatic coating, flow coating, and shower coating are preferable.

The method of drying the coated film after application of the synthetic resin-based latex sealer 14a includes natural drying in which the coated object is left to stand naturally in the air to dry, the coated object or the coated surface. Is dried by heating. In the baking drying, a hot air drying oven, an infrared drying oven, a jet drying oven, a convection drying oven, or the like is used for heating.

The undercoat 15a is used to form an undercoat 15 which is an intermediate layer between the synthetic resin latex sealer 14 and the overcoat 16, and its main purpose is to provide a thick coat. To improve the flatness of the coating film and to prevent water permeability to the cement plate 13. Here, the difference between the undercoat paint 15a and the synthetic resin latex-based sealer 14a can be distinguished also by the blending amount of the extender pigment.
The amount of impregnation into the layer increases, and the peeling prevention layer 14 can be formed.
When the amount of the extender pigment is large, the impregnation amount on the surface 13a is small as in the case of the usual undercoat paint 15a, and it is difficult to form a sealer and a peel-prevention layer. It should be noted that the amount of the compounding amount of the coloring pigment has a small contribution to the amount of impregnation on the surface 13a like the amount of the extender pigment.

Undercoat 1 used in the first embodiment
5a includes a drying oil paint, a natural resin paint, a synthetic resin paint, a cellulose derivative, etc. In order to form a uniform and excellent functional coating film, it is most preferable to use a synthetic resin paint. However, it is desirable to use a water-based paint having a good value, that is, a paint in which the dispersion medium is water.

Examples of the resin component of the synthetic resin paint include a resin synthesized by a condensation reaction and a resin synthesized by addition polymerization. As a resin synthesized by a condensation reaction,
Epoxy resin, phenolic resin, urea resin, urea melamine resin, amino resin, alkyd resin, phthalic acid resin, fatty acid modified phthalic resin, phenol modified phthalic resin,
Examples include an unsaturated polyester resin, a polyurethane resin, an aldehyde resin, and a ketone resin.

Examples of the resin synthesized by addition polymerization include acrylic resins such as polyacrylates and polymethacrylates and copolymers thereof, acrylic-styrene copolymers, acrylic-vinyl acetate copolymers, and acrylic resins. -Vinyl acetate resins such as vinyl chloride copolymer, acrylic-ethylene copolymer, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-styrene copolymer; PVC,
Examples thereof include vinyl chloride resins such as vinyl chloride-acrylic copolymer, vinyl chloride-ethylene copolymer and vinyl chloride-styrene copolymer, and vinylidene chloride resins such as polyvinylidene chloride and copolymers thereof.

In particular, epoxy resin, phenolic resin, urethane resin, acrylic resin, and vinyl acetate resin are used to improve the flatness of the coating film and prevent water permeability to the substrate. preferable.

The undercoat 15a may use a synthetic resin component alone or may contain a pigment and other additives. Other additives include a film-forming aid, a plasticizer, a thickener, a modifier, a dispersant, a wetting agent, an antifoaming agent, a preservative, a fungicide, an antifreezing agent, and a rust inhibitor.

The top coat 16a constitutes the top coat layer 16 in which the coat is in contact with the outside world.
The hard wood chip cement board 11 is required to have a decorative effect of giving color, luster, and the like, and a performance of resisting the aging action or erosion action of the coating film due to sunlight, wind, rain, or various kinds of steam.

The overcoat 16a used in the first embodiment
Examples thereof include a drying oil paint, a natural resin paint, a synthetic resin paint, a cellulose derivative, and the like. However, it is most preferable to use a synthetic resin paint to form the overcoating film layer 16 having an excellent decorative effect and durability. Like the undercoat paint 15a, it is desirable to use a water-based paint having good coating workability.

Examples of the resin component of the synthetic resin paint include a resin synthesized by a condensation reaction and a resin synthesized by addition polymerization. Examples of the resin synthesized by the condensation reaction include epoxy resin, phenol resin, urea resin, urea melamine resin, amino resin, alkyd resin, phthalic resin, fatty acid modified phthalic resin, phenol modified phthalic resin, unsaturated polyester resin, and polyurethane. Resins, aldehyde resins and ketone resins.

The resins synthesized by addition polymerization include acrylic resins such as polyacrylates and polymethacrylates and copolymers thereof, acryl-styrene copolymers, acryl-vinyl acetate copolymers, and acrylic resins. -Vinyl acetate resins such as vinyl chloride copolymer, acrylic-ethylene copolymer, polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, vinyl acetate-ethylene copolymer, vinyl acetate-styrene copolymer; PVC,
Vinyl chloride resin such as vinyl chloride-acryl copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-styrene copolymer, polyvinylidene chloride resin such as polyvinylidene chloride and its copolymer, polyethylene, polypropylene,
Hydrocarbon resins such as polystyrene, polyisobutylene, fluororesin, and silicone resin are exemplified. In addition, synthetic resins obtained by modifying inorganic components such as ceramic-modified fluororesin, ceramic-modified urethane resin, and ceramic-modified acrylic resin, urethane / acrylic, epoxy / acrylic, silicone / acrylic, polyester / acrylic,
Fluororesin / acryl, colloidal silica / acryl,
A composite emulsion containing two or more kinds of different polymers such as nitrocellulose / acryl and melamine resin / acryl in a particle is exemplified.

The top coating 16a may use a synthetic resin component alone or may contain a pigment and other additives. Other additives include a film-forming aid, a plasticizer, a thickener, a modifier, a dispersant, a wetting agent, an antifoaming agent, a preservative, a fungicide, an antifreezing agent, and a rust inhibitor.

The undercoat and topcoat paints 15a, 16a
Is applied to the surface 14b of the synthetic resin-based latex sealer 14 by spray coating such as air spray, cold spray, hot spray, airless spray, aerosol spray, rolling coating such as roller coater or tumbling, flow coating, shower coating, etc. Such as flow coating, electrostatic coating, electrodeposition coating, powder coating, dipping, vacuum press coating, ironing, powder spray coating, brush coating, spatula coating, tampo coating, etc. As a coating method for forming a uniform coating film on an uneven cement substrate, spray coating, electrostatic coating, flow coating, and shower coating are preferable.

The undercoat and overcoat 15a, 16a
After the application of the coating film, the drying method of the coated object is naturally dried in the air naturally and dried, and the applied object or the coated surface is heated and dried by baking drying. In baking drying, a hot air drying oven, an infrared drying oven, a jet drying oven, a convection drying oven, or the like is used for heating.

Next, the operation of the first embodiment will be described.
This will be described with reference to FIG.

In the first embodiment, the cement board 13 is obtained by kneading the wood material 12 and the water which have been finely divided in advance and hot pressing.

The synthetic resin latex sealer 14a is obtained mainly by emulsion polymerization.

The surface 13a of the cement plate 13
The cement plate 13 is coated with a synthetic resin latex-based sealer 14a having excellent impregnating properties, so that the cavities 13c formed by the air bubbles 13b existing in the cement plate 13 are filled. The denseness of the surface 13a increases, and the cement board 13 itself is strengthened.

This synthetic resin latex sealer 14a
The surface 14b has good flatness, and can maintain the surface 16b substantially flat even when the undercoating and overcoating film layers 15, 16 which are thin films are formed, so that the appearance quality can be improved. .

The adhesion between the cement board 13 and the synthetic resin latex sealer 14a or between the synthetic resin latex sealer 14a and the undercoating layer 15 is good.

For this reason, as shown in FIG. 2, even if the joint sealing material 17 and the like affixed to the top coat layer surface 16b are peeled off, as shown by a two-dot chain line in FIG. The abutting portions 15c, 16c of the overcoat layer remain on the surface 14b, or
only c and 16c are synthetic resin latex sealers 14a
The synthetic resin latex sealer 14a remains on the cement board surface 13a only by peeling off from the surface 14b of the cement board.

Therefore, even if the painted cement board 11 includes a large number of the finely divided wood materials 12, there is no possibility that the cement board 13 itself of the painted cement board 11 is peeled or broken.

Therefore, the undercoat and topcoat layers 1
The synthetic resin latex sealer 14a prevents exfoliation or total destruction of the cement board surface 13a while improving the appearance quality and the weather resistance by the means 5 and 16.

In the first embodiment, since the particle size of the synthetic resin latex sealer 14a applied to the painted cement board 11 is 0.01 to 0.3 μm, the density of the hard wood chip is reduced. Surface layer 13a of cement board
And a good affinity range, and the adhesion is even better.

The first embodiment is characterized in that a water-based paint is applied to the upper layer after the sealer coating to form two or more coating layers 15 and 16, but the coating of each layer has a thickness forming function and It has different functions such as appearance quality and weather resistance improving function.

[0048]

【Example】

[0049]

[Experimental example 1] Early strength Portland cement: alumina cement: calcined gypsum: slaked lime = 80: 10: 6: 4 (weight ratio)
Using a cement composition obtained by adding 0.2 parts by weight of sodium citrate to 100 parts by weight of the mixture obtained in the above, the mixture was kneaded at a cement composition: wood material: water = 10: 3.5: 6 (weight ratio). The mixture was evenly spread on a template with a decorative pattern, and a wire net was placed thereon. 90-97
After being heated and pressed at 30 kgf / cm ² with a heating plate at a temperature of 30 ° C., it was released from the mold to obtain the cement plate 13.

The cement plate 13 was left in a dryer at 100 ° C. for 10 minutes and then taken out.
At the time, the surface 13a had a particle diameter of 0.1 μm and a coating viscosity of 8 seconds (Ford Cup No.4 method: JIS-K5400 4.
Acrylic latex sealer (butyl acrylate / methyl methacrylate copolymer, solid content concentration: 30%) was applied at 100 g / m ² with an air gun to perform sealer treatment. Then, after drying at 100 ° C. for 10 minutes, it was cooled at room temperature for 3 hours or more.

Next, the base material is kept warm in the same manner as described above, and an epoxy latex paint (solid content: 40%) is coated at 200 g / m ² to form the undercoat layer 15 at a plate temperature of 60 ° C. It was applied and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint (butyl acrylate / methyl methacrylate copolymer, solid concentration: 40%) was applied as a top coat by the same operation at 150 g / m ^2.
It was applied, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test of the coating film (JIS)
-K5400 8.5.1), adhesion strength (JIS-
A69095-5), water permeability test (JIS-K54)
008.16). The particle diameter is measured by a laser diffraction scattering particle size distribution analyzer (LA manufactured by HORIBA).
−910), the median diameter of the particles was measured.

[0054]

EXPERIMENTAL EXAMPLE 2 An acrylic latex sealer having a latex particle diameter of 0.18 μm was used as the synthetic resin latex sealer 14a in the same manner as in Experimental Example 1.

[0055]

Experimental Example 3 Experimental Example 3 corresponds to claims 2 and 3.
Using an acrylic latex sealer having a latex particle diameter of 0.35 μm, the silicate addition amount is set to 15 parts by weight. Otherwise, the coating was performed in the same manner as in Experimental Example 1.

[0056]

Experimental Example 4 Experimental example 4 is a comparative example with respect to claim 1. The cement board 13 was kept warm according to Experimental Examples 1 to 3, and an epoxy-based latex paint (solid content: 40%) was applied as an undercoat at a board temperature of 60 ° C. at 200 g / m ^{2 and} dried at 100 ° C. for 10 minutes. .

Further, an acrylic latex paint (solid content: 40%) was applied as a top coat by the same operation at 150 g / m ^2.
It was applied, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test, an adhesion strength and a water permeability test of the coating film were carried out in the same manner as in Experimental Examples 1 and 2.

Table 1 below summarizes the comparison results of Experimental Examples 1 to 4.

[0060]

[Table 1] As can be seen from Table 1 above, the painted cement boards according to Experimental Examples 1 to 3 having the synthetic resin latex-based sealer 14a and the painted cement boards according to Experimental Examples 1 to 3 having the same did not have the cross section. It is excellent in all of adhesiveness, adhesive strength, and water permeability.
Within the range of 3 μm, no separation between the cement plate 13 and the synthetic resin latex sealer 14a was observed, indicating that the adhesion was good.

[0061]

Embodiment 2 In Embodiment 2, a synthetic resin latex-based sealer 14a to which an alkyl silicate (reference: JP-A-63-168470) is added is used.

The alkyl silicate is represented by the following formula 1.

[0063]

Embedded image The amount of the alkyl silicate to be added is 30 to 150 parts by weight based on 100 parts by weight of the solid content of the synthetic resin latex sealer 14a.

The above-mentioned alkyl silicate is hydrolyzed by contact with water in the presence of an acid or a base to form a silanol group (S
i-OH) and condenses with silanol groups in the cement substrate to form siloxane chains. The fragile cement plate 13 surface 13a becomes stronger due to the siloxane bond between the base material and the coating film, and the cement plate 13 and the undercoat film layer 1
5 is improved.

The above-mentioned alkyl silicate is oil-soluble and incompatible with water, so that it is dispersed in water by adding a dispersant. Examples of the dispersant include anionic, cationic, and nonionic surfactants, and polymer dispersants such as polyvinyl alcohol and cellulose.

If the addition amount of the alkyl silicate is small, the effect of strengthening the fragile cement board surface 13a is small, and if the addition amount is too large, the film-forming property and adhesion of the coating film are reduced. ~ 150 parts by weight are preferred.

The synthetic resin latex sealer 14a may contain a pigment and other additives. Other additives include a film-forming aid, a plasticizer, a thickener, a modifier, a dispersant, a wetting agent, an antifoaming agent, a preservative, a fungicide, an antifreezing agent, and a rust inhibitor.

[0068]

【Example】

[0069]

Experimental Example 5 Experimental Example 5 corresponds to claims 3 and 4. The cement plate 13 was left in a drier at 100 ° C. for 10 minutes and then taken out. When the temperature of the cement plate was 60 ° C., 100 parts by weight of an acrylic resin having a particle diameter of 0.1 μm and tetraethyl silicate 5 as an alkyl silicate were added.
An acrylic latex sealer (butyl acrylate / methyl methacrylate copolymer) containing 0 parts by weight was applied by an air gun. Then, after drying at 100 ° C. for 10 minutes, it was cooled at room temperature for 3 hours or more.

Next, the substrate was kept warm in the same manner as described above, and an epoxy latex paint was applied as an undercoat when the plate temperature was 60 ° C., and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint (butyl acrylate / methyl methacrylate copolymer) was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test of the coating film (JIS)
-K5400 8.5.1), adhesion strength (JIS-
A69095-5), water permeability test (JIS-K54)
008.16). The particle diameter is measured by a laser diffraction scattering particle size distribution analyzer (LA manufactured by HORIBA).
−910), the median diameter of the particles was measured.

[0073]

EXPERIMENTAL EXAMPLE 6 An acrylic latex paint containing 100 parts by weight of tetraethyl silicate was applied in the same manner as in Experimental Example 3 based on 100 parts by weight of a solid content of an acrylic latex sealer having a particle diameter of 0.1 μm.

[0074]

EXPERIMENTAL EXAMPLE 7 The cement board 13 was kept warm according to the experimental example described above, and an epoxy latex paint was applied as an undercoat when the board temperature was 60 ° C. and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test, adhesion strength and water permeability test of the coating film were carried out in the same manner as in the experimental example.

[0077]

Experimental Example 8 Tetraethyl silicate 1 was added to an acrylic latex sealer having a particle diameter of latex of 0.1 μm.
It was coated in the same manner as in Experimental Example 3 as 0 parts by weight.

[0078]

[Experimental example 9] Tetraethyl silicate 2 was added to an acrylic latex sealer having a particle size of latex particles of 0.1 µm.
The coating was performed in the same manner as in Experimental Example 3 as 00 parts by weight.

Table 2 below summarizes the comparison results of Experimental Examples 5 to 9.

[0080]

[Table 2] As can be seen from Table 2 above, when the synthetic resin latex sealer 14a containing alkyl silicate was applied to the surface 13a of the cement plate 13,
A siloxane bond occurs between the resin and the synthetic resin latex-based sealer 14a, so that the surface 13a becomes stronger and the cement plate 13 itself is less likely to peel and break. In particular, 30 to 15 alkyl silicates per 100 parts by weight of the solid content of the synthetic resin latex sealer 14a.
It can be seen that the painted cement boards 11 of Experimental Examples 5 and 6 containing 0 parts by weight had good cross-cut adhesion and adhesion strength.

The other configuration, operation, and effects are the same as or equivalent to those of the first embodiment, and thus description thereof is omitted.

[0082]

Third Embodiment A third embodiment corresponds to claims 5 and 6. The coated cement board of the present embodiment is characterized in that an inorganic silicate is added to the synthetic resin latex sealer 14a. This inorganic silicate is represented by the following chemical formula 2.

[0083]

Embedded image The addition amount of the inorganic silicate is 10 to 15 parts by weight based on 100 parts by weight of the solid content of the synthetic resin latex sealer.
0 parts by weight.

The metal oxide represented by M in Chemical Formula 1 includes Na ₂ O, K ₂ O, Li ₂ O, MgO,
CaO, PbO, ZnO, SrO, BaO, Al ₂ O _{3 and the} like can be mentioned.

When the inorganic silicate comes into contact with water, a hydrated compound is produced by a chemical reaction, and condenses with a silanol group in the cement base to form a siloxane chain. Due to the siloxane bond between the substrate and the coating film, the surface of the fragile substrate becomes stronger, and the adhesion between the cement plate 13 and the synthetic resin latex sealer 14a is improved.

When the particle size of the inorganic silicate is small, it is difficult to uniformly disperse it in a latex sealer, and the viscosity of the sealer increases. When the particle size is large, the inorganic silicate tends to precipitate and the impregnating property on the substrate surface is reduced. .01 to 10 μm
Is preferred.

If the amount of the inorganic silicate is small, the effect of strengthening the surface of the fragile cement base is small. If the amount is too large, the film formability and adhesion of the coating film are reduced. ~ 150 parts by weight are preferred.

The sealer may contain a pigment and other additives. Other additives include
Film forming aid, plasticizer, thickener, modifier, dispersant, wetting agent,
Examples include an antifoaming agent, a preservative, a fungicide, an antifreezing agent, and a rust inhibitor.

[0089]

【Example】

[0090]

[Experimental example 10] The above substrate was left in a drier at 100 ° C for 10 minutes and then taken out. When the substrate temperature was 60 ° C, the surface of the acrylic resin having a particle size of 0.1 µm was reduced to 100 parts by weight on the surface. An acrylic latex sealer (butyl acrylate / methyl methacrylate copolymer) containing 50 parts by weight of calcium silicate, which is a 0.5 μm inorganic silicate, was applied by an air gun. Then, after drying at 100 ° C. for 10 minutes, it was cooled at room temperature for 3 hours or more.

Next, the substrate was kept warm by the same method as described above, and an epoxy latex paint was applied as an undercoat at a plate temperature of 60 ° C. and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test of the coating film (JIS)
-K5400 8.5.1), adhesion strength (JIS-
A69095-5), water permeability test (JIS-K54)
008.16). The particle diameter is measured by a laser diffraction scattering particle size distribution analyzer (LA manufactured by HORIBA).
−910), the median diameter of the particles was measured.

[0094]

[Experimental Example 11] A particle diameter of 2 μm was used for 100 parts by weight of a solid content of an acrylic latex sealer having a particle diameter of 0.1 μm.
Acrylic latex paint containing 100 parts by weight of aluminum silicate was applied in the same manner as in Experimental Example 6.

[0095]

Experimental Example 12 The cement plate 13 was kept warm according to the experimental example described above. At a plate temperature of 60 ° C., an epoxy latex paint was applied as an undercoat and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test, adhesion strength and water permeability test of the coating film were carried out in the same manner as in the above-mentioned experimental examples.

[0098]

[Experimental example 13] The same method as in Experimental example 10 was applied using tetraethyl silicate as an alkyl silicate.

[0099]

EXPERIMENTAL EXAMPLE 14 A coating was performed in the same manner as in Experimental Example 10 using calcium silicate (particle size 0.5) as an inorganic silicate.

[0100]

EXPERIMENTAL EXAMPLE 15 An acrylic latex sealer having a particle diameter of 0.1 μm of latex particles was coated in the same manner as in Experimental Example 10 with 10 parts by weight of calcium silicate having a particle diameter of 0.5 μm.

[0101]

EXPERIMENTAL EXAMPLE 16 An acrylic latex sealer having a particle diameter of 0.1 μm of latex particles was coated in the same manner as in Experimental Example 10 with 200 parts by weight of calcium silicate having a particle diameter of 0.5 μm.

[0102]

EXPERIMENTAL EXAMPLE 17 An acrylic latex sealer having a particle diameter of 0.1 μm of latex particles was coated in the same manner as in Experimental Example 10 with 50 parts by weight of calcium silicate having a particle diameter of 20 μm.

Table 3 below shows the comparison results of Experimental Examples 10 to 17.
Put together.

[0104]

[Table 3] As can be seen from Table 3, in the case where the synthetic resin latex-based sealer 14a containing inorganic silicate is applied to the surface 13a of the cement plate 13, a siloxane bond occurs between the cement plate 13 and the synthetic resin latex-based sealer 14a. In addition, the surface 13a becomes stronger, and the cement board 13 itself is less likely to peel and break. In particular, the painted cement boards 11 of Experimental Examples 10 and 11 in which 30 to 150 parts by weight of the inorganic silicate is contained with respect to 100 parts by weight of the solid content of the synthetic resin latex-based sealer 14a have good cross-cut adhesion and adhesion strength. It turns out that. Although the inorganic silicate was in the range of 30 to 150 parts by weight in Experimental Example 17, good results as in Experimental Examples 10 and 11 were not obtained because the particle diameter was too large.

The other configuration, operation, and effects are the same as or equivalent to those of the first and second embodiments, and thus the description thereof is omitted.

[0106]

Fourth Embodiment A fourth embodiment corresponds to claims 7 and 8. In the painted cement board of the present embodiment, the synthetic resin latex sealer 14a is formed of a copolymer obtained by copolymerizing an acrylate, a methacrylate, and an aromatic vinyl compound.

The copolymer is an acrylic ester 15
-80% by weight, 10-75% by weight of a methacrylic acid ester, and 10-75% by weight of an aromatic vinyl compound constitute a weight ratio.

Examples of the acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate. And lauryl acrylate. One or more of these are used.

When the proportion of the acrylate is small, the film-forming temperature of the coating film increases, and the elongation of the coating film decreases. When the proportion is large, the mechanical strength of the coating film decreases.

Examples of the above methacrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate. And lauryl methacrylate. One or more of these are used.

When the proportion of the methacrylic acid ester is small, the mechanical strength of the coating film decreases, and when it is large, the film forming temperature of the coating film increases, and the elongation decreases.

Examples of the aromatic vinyl compound include styrene, methylstyrene, α-methylstyrene,
Dimethyl styrene, methoxy styrene, isopropyl styrene, bromo styrene, cyclohexyl styrene, pentafluoro styrene, chloro styrene, dichloro styrene, iodo styrene and the like are used, and one or more of these are used.

When the proportion of the aromatic vinyl compound is small, the waterproofness and alkali resistance of the coating film decrease, and when it is large, the film forming temperature of the coating film increases and the elongation decreases.
Is preferred.

If the particle size of the copolymer (synthetic resin latex sealer) is less than 0.01 μm, the viscosity of the coating material increases, making application and handling difficult. Therefore, the thickness is preferably 0.01 to 0.3 μm because the density is reduced and the denseness and the adhesion to the substrate are reduced.

The above copolymer is obtained by emulsion polymerization.

The sealer may use a synthetic resin component alone or may contain a pigment and other additives. Other additives include a film-forming aid, a plasticizer, a thickener, a modifier, a dispersant, a wetting agent, an antifoaming agent, a preservative, a fungicide, an antifreezing agent, and a rust inhibitor.

[0117]

【Example】

[0118]

EXPERIMENTAL EXAMPLE 18 The cement plate 13 was left in a dryer at 100 ° C. for 10 minutes and then taken out. When the substrate temperature was 60 ° C., the surface had a particle diameter of 0.1 μm and a paint viscosity of 8 seconds (Ford Cup No. Method 4: Acrylic / styrene-based latex sealer (butyl acrylate / methyl methacrylate / styrene copolymer = 40/30/30% by weight) based on JIS-K5400 4.5.4) is applied with an air gun to perform sealer treatment. I did it. Then, after drying at 100 ° C. for 10 minutes, it was cooled at room temperature for 3 hours or more.

Next, the substrate was kept warm by the same method as described above, and an epoxy latex paint was applied as an undercoat at a plate temperature of 60 ° C., and dried at 100 ° C. for 10 minutes.

Further, an acrylic latex paint (butyl acrylate / methyl methacrylate copolymer) was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, the grid adhesion test of the coating film (JIS)
-K5400 8.5.1), adhesion strength (JIS-
A69095-5), water permeability test (JIS-K54)
008.16). The particle diameter is measured by a laser diffraction scattering particle size distribution analyzer (LA manufactured by HORIBA).
−910), the median diameter of the particles was measured.

[0122]

[Experimental Example 19] An acrylic / styrene-based latex sealer having a particle size of latex particles of 0.1 μm (butyl acrylate / methyl methacrylate / styrene copolymer = 60 /
(30/10% by weight) in the same manner as in Experimental Example 18.

[0123]

[Experimental example 20] An acrylic / styrene-based latex sealer (acrylic acid 2) having a latex particle diameter of 0.1 μm
(Ethylhexyl / methyl methacrylate / methylstyrene copolymer = 30/40/30% by weight) was applied in the same manner as in Experimental Example 18.

[0124]

[Experimental Example 21] The substrate was kept warm according to the above example, and an epoxy latex paint was applied as an undercoat at a plate temperature of 60 ° C and dried at 100 ° C for 10 minutes.

Further, an acrylic latex paint was applied as a top coat by the same operation, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, a cross-cut adhesion test, adhesion strength and water permeability test of the coating film were carried out in the same manner as in Experimental Example 18.

[0127]

EXPERIMENTAL EXAMPLE 22 A coating was performed in the same manner as in Experimental Example 18 using an acrylic latex sealer (butyl acrylate / methyl methacrylate = 50/50% by weight) having a particle diameter of latex particles of 0.1 μm.

[0128]

EXPERIMENTAL EXAMPLE 23 An acrylic / styrene-based latex sealer having a particle diameter of latex particles of 0.1 μm (butyl acrylate / methyl methacrylate / styrene copolymer = 10 /
(0/90% by weight) in the same manner as in Experimental Example 18.

[0129]

EXPERIMENTAL EXAMPLE 24 A coating was performed in the same manner as in Experimental Example 18 using an acrylic / styrene-based latex sealer having a particle diameter of latex particles of 0.35 μm.

Table 4 below shows the comparison results of Experimental Examples 18 to 24.
Put together.

[0131]

[Table 4] As can be seen from Table 4 above, in the painted cement plate 11 according to Experimental Examples 18 to 20, the surface 13
Since a is coated with a synthetic resin latex sealer obtained by copolymerizing an acrylate, a methacrylate, and an aromatic vinyl compound at a suitable weight ratio,
It is densified and the adhesiveness between the cement board 13 and the synthetic resin latex-based sealer 14a is increased, the surface 13a becomes stronger, and the cement board 13 itself is hardly peeled or broken, and has excellent water permeability. . In Example 24, a synthetic resin latex-based sealer having the same composition and weight ratio was applied, but the particle size was too large to obtain good results as in Experimental Examples 18 to 20.

The other configurations, functions, and effects are the same as or equivalent to those of the first to third embodiments, and thus description thereof is omitted.

[0133]

Embodiment 5 In Embodiment 5, the synthetic resin latex sealer 14a is composed of an acrylic copolymer and a water-soluble polymer or a water-soluble copolymer containing an ethylenically unsaturated carboxylic acid.

Here, the acrylic copolymer includes an alkyl acrylate having 1 to 18 carbon atoms in an alkyl group and / or a methacrylic acid alkyl ester having 1 to 18 carbon atoms in an alkyl group, and a monomer thereof. It is obtained by emulsion polymerization of the polymer and a copolymerizable monomer. This acrylic copolymer is insoluble in water.

Examples of the alkyl acrylate having an alkyl group having 1 to 18 carbon atoms include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, amyl acrylate, and acrylic acid. Examples include isoamyl, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and the like. In particular, an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferably used.

Examples of the alkyl methacrylate having an alkyl group having 1 to 18 carbon atoms include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, amyl methacrylate, and the like. Isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate,
Lauryl methacrylate and the like can be mentioned. Especially,
Alkyl methacrylates having 1 to 8 carbon atoms in the alkyl group are preferably used.

The monomers copolymerizable with these alkyl acrylates and alkyl methacrylates include, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, Crotonic acid, acotinic acid, ethylenically unsaturated carboxylic acids including unsaturated carboxylic acids such as citraconic acid, vinyl acetate, butadiene, isoprene, styrene,
vinyl compounds such as α-methylstyrene, halogenated styrene, divinylbenzene, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-
Methylacrylamide, N-methylmethacrylamide,
Amide compounds such as N-methylol acrylamide and N-methylol methacrylamide are exemplified.

On the other hand, as the ethylenically unsaturated carboxylic acid contained in the water-soluble polymer (homopolymer) or the water-soluble copolymer, for example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, Unsaturated carboxylic acids such as fumaric acid, fumaric anhydride, crotonic acid, acotinic acid, citraconic acid and the like can be mentioned. Examples of the monomer copolymerizable with the ethylenically unsaturated carboxylic acid include the above-mentioned alkyl acrylate, alkyl methacrylate, vinyl compound, amide compound and the like.

When the ratio of the water-soluble polymer or water-soluble copolymer in the synthetic resin latex sealer 14a is small, the impregnating property and adhesion to the hard wood chip cement board are reduced, and when it is large, the waterproof property is reduced. 5-30% by weight
Is preferred.

The particle size of the synthetic resin latex sealer 14a in Embodiment 5, pigments and other additives contained therein, the undercoat 15a, the topcoat 1
6a, the method of applying each paint and the method of drying the coating film are the same as those in the first embodiment, and a description thereof will be omitted.

[0141]

【Example】

[0142]

[Experiment 25] This experiment 25 and an experiment 26 described later.
In Nos. To 30, a cement plate 13 was obtained by the same heat and pressure molding as in the first embodiment.

The cement plate 13 was left in a drier at 100 ° C. for 10 minutes and then taken out.
At the time, the surface 13a had a particle diameter of 0.1 μm and a coating viscosity of 8 seconds (Ford Cup No.4 method: JIS-K5400 4.
5.4) aqueous dispersion (acrylic copolymer (butyl acrylate / methyl methacrylate copolymer) 80% by weight, water-soluble polymer (acrylic acid polymer) 20% by weight, solid content concentration 30% ) Was applied at 100 g / m ² with an air gun and subjected to a sealer treatment. Then, it dried at 100 degreeC for 10 minutes.

Next, the cement board 13 was kept warm by the same method as described above, and when the board temperature was 60 ° C., 200 g / m ² of an epoxy-based latex paint (solid content concentration: 40%) was applied as the undercoat paint 15a. Dried for 10 minutes.

Further, by the same operation, an acrylic latex paint (butyl acrylate /
(Methyl methacrylate copolymer, solid content concentration 40%)
50 g / m ^{2 was} applied, dried at 100 ° C. for 10 minutes, and cooled at room temperature for 3 hours or more.

Thereafter, the grid adhesion test of the coating film (JIS)
-K5400 8.5.1), adhesion strength (JIS-
A69095-5), water permeability test (JIS-K54)
008.16). The median diameter of the particles was measured with a laser diffraction / scattering particle size distribution analyzer (LA-910, manufactured by HORIBA).

[0147]

EXPERIMENTAL EXAMPLE 26 A water-soluble polymer in an aqueous dispersion was used as a water-soluble copolymer (styrene / maleic acid copolymer) in the same manner as in Experimental Example 25, and each test was conducted.

[0148]

[Experimental Example 27] An acrylic copolymer (butyl acrylate / methyl methacrylate copolymer) in an aqueous dispersion was mixed with 95
5% by weight of water-soluble polymer (acrylic acid polymer)
, And each test was performed in the same manner as in Experimental Example 25.

[0149]

[Experimental example 28] An acrylic copolymer (butyl acrylate / methyl methacrylate copolymer) in an aqueous dispersion was mixed with 10
Coating was carried out in the same manner as in Experimental Example 25, except that 0% by weight, water-soluble polymer and water-soluble copolymer were not added, and each test was performed.

[0150]

Experimental Example 29 An acrylic copolymer (butyl acrylate / methyl methacrylate copolymer) in an aqueous dispersion was mixed with 60
The coating was carried out in the same manner as in Experimental Example 25, with the water-soluble polymer (acrylic acid polymer) being 40% by weight, and each test was carried out.

[0151]

[Experimental Example 30] Coating and various tests were performed in the same manner as in Experimental Example 25, except that the sealer treatment was not performed (the peeling preventing layer 14 was not formed).

Table 5 below summarizes the comparison results of Experimental Examples 25 to 30.

[0153]

[Table 5] As can be seen from Table 5, the coated cement boards of Experimental Examples 25 to 27 according to Claims 9 and 10 obtained good results in each of the grid adhesion strength, the adhesion strength, and the water permeability test. I have. On the other hand, in the adhesion strength test for the painted cement board of Experimental Example 28 in which the water-soluble polymer and the water-soluble copolymer were not contained in the sealer, all the test items were obtained for the painted cement board of Example 30 in which no sealer treatment was performed. , The results were inferior to those of Experimental Examples 25 to 27, respectively. In addition, the coated cement board according to Experimental Example 29 contained a water-soluble polymer in an amount exceeding the above-mentioned preferable addition amount (5 to 30% by weight), and thus resulted in poor waterproofness.

[0154]

Embodiment 6 The painted cement boards 11 are generally stacked when they are stored. When the painted surfaces of the painted cement board 11 are in direct contact with each other during this lamination, if the Tg (glass transition temperature) of the applied synthetic resin latex sealer 14a is low and the formed peel prevention layer 14 is soft, So-called blocking may occur, in which the coating film of one painted cement plate 11 sticks to and peels off the coated film of another painted cement plate 11 that is stacked directly above it.

As a method for preventing such blocking, there is a method of laying paper between the painted cement plates 11 to be stacked. However, this method has a disadvantage that the number of steps, man-hours, costs and the like increase. Further, such a blocking can be prevented by using a sealer having a high Tg, but the film forming temperature is increased due to the high Tg,
There is a disadvantage that the drying temperature and the drying time after coating must be increased.

In the sixth embodiment, in consideration of such a problem, T
g of a methacrylic acid alkyl ester-based polymer particle as a core and dispersed in an aqueous medium, and the methacrylic acid alkyl ester-based polymer particle and an alkyl acrylate ester as a shell component that gives a polymer having a low Tg. Emulsion polymerization produces core / shell type particles, and a synthetic resin latex sealer 14a containing the core / shell type latex particles as a main component.
Is applied to the cement plate 13. The Tg of the alkyl acrylate polymer is preferably lower than the Tg of the alkyl methacrylate-based polymer particles,
The former is desirably 10 ° C or lower, and the latter is desirably 10 ° C or higher.

The latex particles 18 of the synthetic resin latex sealer 14a have a structure in which the core 18a has a high Tg (ie, is hard) and the shell 18b has a low Tg (ie, is soft) as schematically shown in FIG. . On the other hand, the film forming property of the latex particles 18 largely depends on the Tg of the shell 18b. The lower the Tg, the lower the film forming temperature. Therefore, the drying temperature of the latex particles 18 is relatively low, and the drying time is relatively short. Is also easily formed. Also, the core 18a is Tg
Is high, the coating film of the synthetic resin latex sealer 14a containing the latex particles 18 as a main component is less likely to be blocked than a conventional coating film having a low Tg.

Examples of the alkyl methacrylate polymer particles used as the core 18a include polymers mainly containing an alkyl methacrylate having an alkyl group having 1 to 18 carbon atoms, such as methyl methacrylate and ethyl methacrylate. , Propyl methacrylate, methacrylic acid n
-Butyl, isobutyl methacrylate, amyl methacrylate, isoamyl methacrylate, hexyl methacrylate,
Examples include homopolymers such as 2-ethylhexyl methacrylate and lauryl methacrylate, and particles of a copolymer with another monomer.

The alkyl acrylate used as a component constituting the shell 18b is one having an alkyl group having 1 to 18 carbon atoms, for example, methyl acrylate, ethyl acrylate, propyl acrylate, n-acrylate. -Butyl, isobutyl acrylate, amyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, and the like. In particular, the alkyl group has 1 to 8 carbon atoms.
Is preferably used.

The alkyl methacrylate-based polymer or alkyl acrylate may be copolymerized with a monomer copolymerizable with the monomer. For example, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, acotinic acid,
Ethylenically unsaturated carboxylic acids including unsaturated carboxylic acids such as citraconic acid, vinyl acetate, vinyl compounds such as butadiene, isoprene, styrene, α-methylstyrene, halogenated styrene, divinylbenzene, acrylonitrile, methacrylonitrile, and acrylamide , Methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-
Amide compounds such as methylol methacrylamide are exemplified.

When the amount of the alkyl acrylate added to the methacrylic acid alkyl ester-based polymer is small, the film forming temperature of the resulting synthetic resin latex sealer 14a becomes high, and when it is large, the blocking occurs when the painted cement boards 11 are stacked. Is caused, 10 to 15 parts by weight per 100 parts by weight of the alkyl methacrylate polymer.
It is required to be 0 parts by weight, and more preferably 20 to 120 parts by weight.

The above emulsion polymerization can be performed under ordinary emulsion polymerization conditions. For example, emulsifiers in aqueous media,
A polymerization initiator, a pH adjuster, a solvent and the like are added, and a temperature of 30 to
The reaction may be performed at about 100 ° C. for about 1 to 30 hours.

As the emulsifier, anionic, nonionic or anionic-nonionic combinations are used.
Examples of the anionic emulsifier include higher alcohol sulfate sodium salt, alkylbenzene sulfonate sodium salt, succinic acid dialkyl ester sulfonate sodium salt, and alkyl diphenyl ether disulfonate sodium salt. Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether and the like. Further, so-called reactive emulsifiers which can be copolymerized with the above-mentioned monomers, for example, sodium styrenesulfonate, sodium allylalkylsulfonate and the like may be used.

The amount of the emulsifier used is usually 0.1 part by weight based on 100 parts by weight of the total of the core alkyl methacrylate polymer particles and the monomer mixture emulsion-polymerized therewith.
It is about 0.5 to 5 parts by weight.

As the polymerization initiator, a water-soluble polymerization initiator is suitable, and examples thereof include persulfates such as potassium persulfate and ammonium persulfate, and hydrogen peroxide. The amount of the polymerization initiator to be added is about 0.05 to 3 parts by weight based on 100 parts by weight of the monomer mixture.

Emulsion polymerization using the above-mentioned alkyl methacrylate polymer particles as a core is carried out by a known method, for example,
A method in which the total amount of monomers is charged to the reaction system in the presence of alkyl methacrylate polymer particles in a batch, and the remaining monomers are continuously or divided after charging and reacting a part of the monomers. It can be carried out by a method of charging, a method of continuously charging the total amount of monomers, or the like.

The particle size of the synthetic resin latex sealer 14a in the sixth embodiment, the pigments and other additives that can be contained therein, the coating method, and the method of drying the coating film are the same as those in the first embodiment. Therefore, the description is omitted. Although the undercoat layer 15 and the overcoat layer 16 are finally formed on the produced coated cement board 11, the blocking property evaluation test described later is based on the coating layer (the anti-peeling layer) formed by the synthetic resin sealer 14a. ) At the stage when the formation of 14 was completed.

[0168]

【Example】

[0169]

Experimental Example 31 Experimental Example 31 and Experimental Example 32 to be described later.
In Nos. To 36, the cement plate 13 was obtained by the same heating and pressing as in the first embodiment.

On the other hand, the synthetic resin latex sealer 14
a was produced as follows. That is, first, a heater and a nitrogen gas introducing device were attached to a stainless steel autoclave equipped with a stirrer, a thermometer, and an addition pump, and an aqueous dispersion (solid content of 10%) of methyl methacrylate polymer particles was added thereto.
0 parts by weight, 333 parts by weight of a particle diameter of 0.1 μm) and 0.1 part by weight of ammonium persulfate as a polymerization initiator were added,
The mixture was stirred at 80 ° C. under a nitrogen gas atmosphere. Next, 0.3 parts by weight of sodium alkylbenzenesulfonate as an emulsifier, 30 parts by weight of n-butyl acrylate, 70 parts of ionic water
The emulsified liquid obtained by stirring parts by weight at a high speed was added to the emulsion by an addition pump.
It was added continuously over time. After the addition is completed, another 85
Aged at 1 ° C. for 1 hour, cooled and adjusted to pH 8 with aqueous ammonia. This was filtered through a 100 mesh wire mesh to obtain an aqueous dispersion (solid content: 30%, particle size: 0.12 μm).
m) was obtained and 3 parts by weight of butyl cellosolve and 0.5 part by weight of a silicone-based antifoaming agent were added to 100 parts by weight of this aqueous dispersion as a film-forming aid to obtain a synthetic resin latex-based sealer 14a.

The cement plate 13 was left in a dryer at 100 ° C. for 10 minutes and then taken out.
At the time, the synthetic resin latex sealer 14 is applied to the surface 13a.
a at 100 g / m ² with an air gun,
Dried for minutes. The same procedure was applied to the back surface of the cement plate 13.

Thereafter, a blocking evaluation test and a cross-cut adhesion test (JIS-K5400) of the coating film were conducted by the following methods.
8.5.1). The median diameter of the particles was measured with a laser diffraction / scattering particle size distribution analyzer (LA-910, manufactured by HORIBA).

[Testing Method for Evaluation of Blocking Property] 45, 6
In an atmosphere of 0 ° C., the synthetic resin latex sealer 1
2 kg of cement board 13 coated with 4a and 3 kgf
/ M ² for 2 hours. Surface 13 after pressing
The peeling (blocking state) of the coating film (a) was observed and judged according to the following criteria.

○: The coating film was not peeled off at both 45 ° C. and 60 ° C. atmosphere (blocking hardly occurred).

Δ: not peeled at 45 ° C., but at 60 ° C.
In this case, the coating films of the two cement plates 13 adhere to each other, and the coating films are peeled off at the interface with the cement plate 13.

X: At 45 ° C., the coating films of the two cement plates 13 adhere to each other, and the coating films are peeled off at the interface with the cement plate 13 (blocking is likely to occur).

[0177]

Experimental Example 32 100 parts by weight of an alkyl methacrylate-based polymer (weight composition ratio: methyl methacrylate polymer / butyl acrylate = 90/10) in an aqueous dispersion,
The coating was carried out in the same manner as in Experimental Example 31 with the added monomer (weight composition ratio: 2-ethylhexyl acrylate / styrene = 80/20) being 100 parts by weight, and each test was carried out.

[0178]

EXPERIMENTAL EXAMPLE 33 An alkyl methacrylate-based polymer (methyl methacrylate polymer) in an aqueous dispersion was mixed with 100
The coating was performed in the same manner as in Experimental Example 31 without adding a monomer, and each test was performed.

[0179]

EXPERIMENTAL EXAMPLE 34 The aqueous dispersion does not contain an alkyl methacrylate polymer, and 30 parts by weight of a monomer (n-butyl acrylate) is added, followed by coating in the same manner as in Experimental Example 31. Each test was performed.

[0180]

EXPERIMENTAL EXAMPLE 35 An alkyl methacrylate-based polymer (methyl methacrylate polymer) in an aqueous dispersion was mixed with 100
5 parts by weight of the added monomer (n-butyl acrylate)
The coating was performed in the same manner as in Experimental Example 31 as a part by weight, and each test was performed.

[0181]

[Experimental Example 36] An alkyl methacrylate polymer (methyl methacrylate polymer) in an aqueous dispersion was 100
1 part by weight of the added monomer (n-butyl acrylate)
The coating and the respective tests were performed in the same manner as in Experimental Example 31 with 80 parts by weight.

Table 6 below summarizes the comparison results of Experimental Examples 32-36.

[0183]

[Table 6] As can be seen from Table 6, none of the coated cement boards of Experimental Examples 31 and 32 according to the present embodiment had any blocking, and no peeling with the grid tape. It was confirmed that the coating films of these coated cement boards were hard and had no sticky feeling, and there was no risk of blocking during loading. In addition, since the drying temperature can be lowered and the drying time can be shortened in the production of the coated cement board, the productivity can be improved.

On the other hand, each of the coated cement boards of Experimental Examples 33 and 35 containing no monomer which is emulsion-polymerized with the methacrylic acid alkyl ester-based polymer particles or having a relatively small amount does not exhibit blocking. Although not easily generated, the coating film is easy to peel off, and does not contain the core alkyl methacrylate polymer, or the amount thereof is relatively small. Is difficult to peel off, but tends to cause blocking.

Although the first to sixth embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the first to sixth embodiments, and the design is within a range not departing from the gist of the present invention. Modifications are included in the present invention.

For example, in the first to fifth embodiments, the coating layer on the surface is changed to the undercoating layer 15 and the overcoating layer 16.
However, the present invention is not limited to this. For example, a single layer or a plurality of layers of three or more layers may be used as long as they are formed by being applied from above the anti-peeling layer 14. .

[0187]

As described above, according to the first aspect of the present invention, even if the joint sealing material or the like attached to the surface of the coating film layer is peeled off, the coating film layer is prevented from peeling. Simply peeling from the surface of the layer, the anti-peeling layer remains on the surface of the hard wood cement board.

[0188] Therefore, even in the case of a hard wood chip cement board containing finely divided wood material, there is no possibility that the hard wood chip cement board itself is peeled or broken.

[0189] Therefore, the peeling prevention layer prevents peeling of the substrate while improving the appearance quality and weather resistance by the coating layer.

According to the second aspect of the present invention, since the synthetic resin latex sealer of the coated cement board has a particle size of 0.01 to 0.3 μm, the denseness of the hard cemented cement board is reduced. It has a practically useful effect of being in a range of good affinity with the layer and having better adhesion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a painted cement board according to the first embodiment.

FIG. 2 is a cross-sectional view illustrating a state in which a joint sealing material is peeled off on the painted cement board of the first embodiment.

FIG. 3 is an explanatory view schematically showing a synthetic resin latex sealer according to a sixth embodiment.

FIG. 4 is a sectional view of a conventional building exterior wall panel.

[Explanation of symbols]

 12 Woody material 13 Cement board 13a Surface 14 Anti-peeling layer 14a Synthetic resin latex sealer 15 Undercoat layer 15a Undercoat 16 Topcoat 16a Topcoat

Claims (14)

[Claims] 1. A synthetic resin latex-based sealer is applied to the surface of a cement plate to form an anti-peeling layer,
A coated cement plate, comprising a coating layer formed by applying a coating material on the anti-peeling layer. 2. The coated cement board according to claim 1, wherein said synthetic resin latex sealer has a particle size of 0.01 to 0.3 μm. 3. The synthetic resin latex-based sealer contains an alkyl silicate.
Or the coated cement board according to 2. 4. The alkyl silicate is used in an amount of 3 parts by weight based on 100 parts by weight of the solid content of the synthetic resin latex sealer.
The coated cement board according to claim 3, wherein the amount is 0 to 150 parts by weight. 5. The coated cement board according to claim 1, wherein the synthetic resin latex sealer contains an inorganic silicate. 6. The inorganic silicate is used in an amount of 30 to 100 parts by weight based on 100 parts by weight of the solid content of the synthetic resin latex sealer.
The coated cement board according to claim 5, wherein the amount is 150 parts by weight. 7. The synthetic resin latex-based sealer is made of a copolymer obtained by copolymerizing an acrylic ester, a methacrylic ester, and an aromatic vinyl compound. Painted cement board as described. 8. The acrylate ester 15
The coated cement board according to claim 7, wherein the weight ratio is constituted by -80% by weight, 10-75% by weight of a methacrylate, and 10-75% by weight of an aromatic vinyl compound. 9. The synthetic resin latex sealer comprises an acrylic copolymer and a water-soluble polymer or a water-soluble copolymer containing an ethylenically unsaturated carboxylic acid. 2. The coated cement board according to 2. 10. The acrylic copolymer comprises an alkyl acrylate having 1 to 18 carbon atoms in an alkyl group and / or a methacrylic acid alkyl ester having 1 to 18 carbon atoms in an alkyl group. The coated cement plate according to claim 9, which is obtained by emulsion polymerization of a possible monomer. 11. The coated cement board according to claim 1, wherein said synthetic resin latex-based sealer includes core / shell type particles, and said shell is softer than said core. 12. The polymer comprising the component constituting the shell, wherein the Tg of the polymer comprising the component constituting the shell is lower than the Tg of the core, the Tg of the core is not lower than 10 ° C. The coated cement board according to claim 11, wherein the temperature is 10 ° C or less. 13. The core has an alkyl group having 1 to 1 carbon atoms.
8, comprising a methacrylic acid alkyl ester-based polymer,
13. The coated cement board according to claim 11, wherein the shell comprises an alkyl acrylate polymer having 1 to 18 carbon atoms in an alkyl group. 14. The coated cement board according to claim 1, wherein the coating layer formed on the peel-preventing layer is two or more coating layers formed of a water-based paint.