JP2000140751A - Inorganic decorative sheet finished with photo-curable clear coating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorg. decorative sheet finished with a photo-curable clear coating with excellent thickness feeling, high lustor durability for a long term weatherability for a long term, adhesiveness for a long term, and peeling resistance for a long term and being suitably usable as an exterior material such as an exterior wall and a roofing. SOLUTION: At least one face of an inorg. decorative sheet 10 primer-treated with an acrylic emulsion enamel coating material is coated with a photo-curable clear coating compsn. contg. a photo-curable (meth)acrylate compd. and a photo- polymn. initiator. At least one face of an inorg. decorative sheet 10 is primer- treated with an acrylic emulsion enamel coating material and the surface of this primer-treated inorg. decorative sheet 10 is coated with a photo-curable clear coating compsn. contg. a photo-curable (meth)acrylate compd. and a photo- polymn. initiator, and then, the coated face of the photo-curable clear coating compsn. is cured by irradiating it with light. The compd. is pref. a photo-curable urethane (meth)acrylate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inorganic decorative board finished with a photocurable clear coating and a method for producing the same, and more particularly, to a feeling of firmness, long-term high gloss persistence, long-term weatherability, long-term adhesion, and long-term durability. The present invention relates to a light-curable clear-painted inorganic decorative plate excellent in peelability and suitable for use as an exterior material such as an outer wall or a roof, and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION As a decorative veneer for exterior use, an inorganic decorative veneer coated with an acrylic enamel paint is widely used at present.

[0003] Such a decorative board is stretched as an outer wall material, a roofing material or the like, and after more than five years, chalking (chalking) becomes conspicuous, so that the paint must be repainted.

[0004] In order to prevent the choking, recently, acrylic enamel-coated inorganic decorative boards have been further coated with an acrylic clear paint on the surface thereof.

[0005] However, these paints require a long time for drying, and the resulting dried coating film is easily damaged.
Since blocking is apt to occur, extra care must be taken in transporting and handling operations, such as inserting interleaving paper between decorative boards during stacking and packing.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, which can be cured instantly after coating with a paint, and the cured coated surface is hardly damaged and has a blocking property. It is an object of the present invention to provide an inorganic decorative board having high weather resistance that can be used for exterior without fear of occurrence.

Another object of the present invention is to provide a method for producing an inorganic decorative board as described above.

[0008]

SUMMARY OF THE INVENTION The inorganic decorative board finished with a photocurable clear coating according to the present invention has a photocurable (meth) acrylate compound (a) in which at least one surface of the inorganic decorative board that has been ground-treated with an acrylic emulsion enamel paint. ) And a photocurable clear coating film formed from a photocurable clear coating composition containing a photopolymerization initiator (b).

In a preferred embodiment of the present invention, the photocurable (meth) acrylate compound (a) is preferably a photocurable urethane (meth) acrylate compound. In the method for producing a light-curable clear-painted inorganic decorative board according to the present invention, at least one surface of the inorganic decorative board is subjected to a base treatment with an acrylic emulsion enamel paint,
A photocurable clear coating composition containing a photocurable (meth) acrylate compound (a) and a photopolymerization initiator (b) is applied to the surface of the inorganic decorative plate that has been subjected to the base treatment with the acrylic emulsion enamel paint. Then, the coated surface of the photocurable clear coating composition is irradiated with light to be cured.

In a preferred embodiment of the present invention, the photocurable (meth) acrylate compound (a) is preferably a photocurable urethane (meth) acrylate compound. According to the present invention, it can be cured instantly after coating with a paint, and the obtained cured coated surface is hardly damaged, has no fear of blocking, and has high weather resistance such that it can be used for exterior use. An inorganic decorative board is provided.

Further, according to the present invention, there is provided an efficient method for producing an inorganic decorative board as described above.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The photocurable clear-painted inorganic decorative board and the method for producing the same according to the present invention will be specifically described below with reference to the drawings. <Inorganic decorative board> FIG. 1 is a longitudinal sectional view showing a preferred embodiment of an inorganic decorative board finished with a photocurable clear coating according to the present invention.

In the inorganic decorative plate 10 shown in FIG. 1, a first base coat 30 made of a sealer or the like is applied on the entire surface 21 of the inorganic porous base material 20 including the concave portions 20a and the convex portions 20b. A second base (colored) coating 40 formed by applying an acrylic emulsion enamel paint is applied on the entire surface 31 of the first base coating 30. On the convex surface 40b of the substrate on which the first and second base coats 30 and 40 are sequentially applied in this manner, a first convex coat 50 made by applying an acrylic emulsion enamel paint is applied. Have been.

Further, the surface 50b of the first convex coating film 50
A photocurable clear coating film 60 formed by applying and curing a photocurable clear coating composition containing a photocurable (meth) acrylate compound (a) and a photopolymerization initiator (b).

Hereinafter, each layer constituting the inorganic decorative plate 10 will be described in order. <Substrate> The substrate 20 may be a flat plate, or a concavo-convex plate 20 having a concave surface 20a as a joint and a flat convex surface 20b on its surface as shown in FIG. Various shapes such as those having a small uneven pattern (not shown) are used, and examples of the material include resin, wood, metal, slate, calcium silicate board, and wood chip cement board. Inorganic porous plates such as slate plates, calcium silicate plates, and wood chip cement plates are preferred. In addition, the dimensions are not particularly limited, but are usually about 1 to 4 m in length, 0.3 to 1 m in width, and about 0.01 to 0.05 m in thickness from the viewpoint of factory productivity, handling convenience, and the like. There are many. <First undercoat> When the base material 20 is an alkaline inorganic porous base material, as shown by reference numeral 30 in FIG. 1, prevention of alkali bleeding to the base material surface and prevention of base material surface By subjecting the base material to a sealer treatment for solidifying or strengthening the powdered brittle part, the first base coat 30
Is desirably formed.

For these sealer treatments, urethane-based, epoxy-based, and water-glass-modified acrylic emulsion-based sealers can be mainly used. However, in consideration of the impregnating property to the substrate and the effect of reinforcing the surface of the substrate. Then, a urethane-based sealer is preferable.

As a urethane sealer, MDI
(4,4'-diphenylmethane diisocyanate) prepolymer, HDI (hexamethylene diisocyanate)
An isocyanate-based prepolymer such as a prepolymer is mentioned, and as an epoxy-based sealer, an ordinary epoxy resin / amine curing agent compounding type is used. As a water glass-modified acrylic emulsion-based sealer, Na is used.
Water-glass-containing acrylic emulsions such as water-based, K-based, and Li-based. <Second Undercoating Film> The second undercoating (coloring) coating film 40 is applied on the entire surface 31 of the first undercoating film 30 and includes, for example,
It is coated with an enamel paint to conceal the first base coat 30 and is used for the purpose of coloring.

The enamel paint mainly contains various color pigments, a resin varnish as a vehicle, and a solvent as a diluent. Examples of the resin varnish include acrylic, acrylic urethane, and acrylic emulsion resin varnishes. For the overcoating of the second base coat 40,
As described later, since a photocurable clear coating composition capable of obtaining a high-hardness coating film is applied, an acrylic emulsion-based resin varnish capable of obtaining a high-strength, high-molecular weight coating film is preferable.

The acrylic emulsion has a monomer composition (MMA / BA) of 90/10 to 50/50,
Preferably, the ratio is 80/20 to 60/40 (weight ratio). It is desirable that the weight average molecular weight is usually 100,000 to 1,500,000, preferably 300,000 to 1,000,000.

The pigment volume concentration (PVC), which is the volume percentage of the pigment contained in the dried coating film, is usually from 10 to 25.
%, Preferably 15 to 20%. The film thickness of the second base colored coating film is, for example, 20 to 5
It is about 0 μm. <First convex portion coating film> As the first convex portion (colored) coating film 50,
Except that the hue is different from that of the second base coat 40,
The same thing as the base coat 40 is applied. The first convex coating film 50 is applied only to the convex portions 40b of the second base coating film. As described above, the first base film which is different only in the hue from the second base coating film is used.
When the convex coating is applied to the convex portion 40b on the surface of the second base coating film, the hue is different between the concave portion A and the convex portion B, and the second base coating film 40 and the first convex coating are coated. An inorganic decorative plate 10 having excellent adhesion to the film 50 is obtained.

The thickness of the first convex coating film is, for example, about 10 to 20 μm. Further, in order to provide designability, a printed pattern using exterior ink or a sputter pattern using colored paint can be provided on the first convex coating film 50. On the other hand, the first convex coating film 50 is for imparting a design property and may be omitted. <Light-curing clear coating film> A light-curing clear coating film 60 is applied on the surface of the first convex coating film 50. A photocurable clear coating composition containing a (meth) acrylate compound (a) and a photopolymerization initiator (b) is used.

This photocurable (meth) acrylate compound
(a) is a photocurable clear coating composition in 100 parts by weight,
Usually 20 to 90 parts by weight, preferably 30 to 70 parts by weight,
More preferably, it is contained in an amount of 40 to 60 parts by weight. The photopolymerization initiator (b) is used in an amount of usually 1 to 10 parts by weight, preferably 3 to 7 parts by weight, more preferably 4 to 10 parts by weight, based on 100 parts by weight of the photocurable clear coating composition.
Desirably, it is contained in an amount of 6 parts by weight.

Photocurable (meth) acrylate compound (a)
Examples thereof include epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) acrylate. Urethane (meth) acrylate is preferably used for exteriors because of its excellent light resistance.

This urethane (meth) acrylate is obtained, for example, by reacting a diisocyanate, a polyol and a hydroxyacrylate, and has an acryloyl group (CH ₂ ＣＨCH—CO ₂₎ as a functional group in the molecule.
-) or a methacryloyl group _{(CH 2 = C (CH 3} ) -
CO-) and a urethane bond (-NH-COO-).

Examples of the diisocyanates include hexamethylene diisocyanate [HDI], isophorone diisocyanate [IPDI], methylene bis (4-cyclohexyl isocyanate) [HMDI], and trimethylhexamethylene diisocyanate [TMHMD].
I] and the like.

Specific examples of the polyols include poly (propylene oxide) diol, poly (propylene oxide) triol, and poly (tetramethylene oxide) diol.

Specific examples of hydroxy acrylates include 2-hydroxyethyl acrylate [HEA],
2-hydroxyethyl methacrylate [HEMA], 2-hydroxypropyl acrylate [HPA], glycidol dimethacrylate [GDMA], pentaerythritol triacrylate [PETA] and the like.

On the other hand, as the photopolymerization initiator (b), benzophenone-based benzophenone, thioxanthone-based 2-chlorothioxanthone, benzoin-based benzyldimethylketal, acetophenone-based 1-hydroxydimethylphenylketone, 1-hydroxycyclohexylphenyl Ketone, 2-methyl-4'-methylthio-2-
Morifolino propiophenone and the like.

The photocurable clear coating composition may contain a reactive diluent, a polymerization inhibitor, a non-reactive diluent, a matting agent, an antifoaming agent, an anti-settling agent, a leveling agent, etc., if necessary. It can be blended within a range not contrary to the purpose.

The thickness of such a photocurable clear coating film is, for example, about 10 to 50 μm. <Coating Method> Next, a method for producing the inorganic decorative plate finished with photocurable clear coating according to the present invention will be described. <Undercoat treatment by sealer (first undercoating)> For example,
A urethane sealer diluted with a diluent to an appropriate viscosity (eg, M
DI, HDI isocyanate prepolymer) and the like are applied using a roll coater, a flow coater, a spray coater or the like, and dried to form a first undercoat film 30 reinforced with resin impregnated on the surface of the base material. I do. That is, the first undercoat film is formed by impregnating and absorbing a sealer into porous and highly absorbent pores on the substrate surface.
Although schematically shown as an independent layer in the above, usually, the substrate surface portion and the base treatment portion are continuously integrated.

The diluent addition rate is usually 100 to 10
It is desirably 00%, preferably 200 to 500%, and more preferably 300 to 400%. Further, such a sealer is applied in an amount of about 50 to 200 g / m ² , though it varies depending on the type of the base material. <Second base colored coating> An acrylic emulsion enamel paint (i) diluted with water to an appropriate viscosity was applied to the entire surface of the base material treated with the sealer by a roll coater, a flow coater,
The second base coat 40 is formed by painting using a spray coater or the like. The dilution rate at this time is 0 to 30%, preferably 10 to 20% in the case of roll coater coating,
For flow coater and spray coating, 10 to 50
%, Preferably 20 to 30%.

The coating amount is determined by the hiding power of the coloring paint used,
Although it depends on the coloring property and is not determined unconditionally, usually 50
To 200 g / m ^2, it is desirable that preferably is 100 to 150 g / m ^2.

In order to dry the colored coating thus applied, hot air at 80 to 100 ° C. may be applied for 5 to 10 minutes. <First convex portion colored coating> Next, in the present invention, as shown in FIG.
The first convex part coating film 50 may be formed by applying an acrylic emulsion paint (ii) having only a hue different from that of the acrylic emulsion enamel paint (i) on b.

A sponge roll coater or the like is used to apply the acrylic emulsion enamel paint (ii) only on the projecting surface of the second base coat 40 as described above.
The dilution ratio at this time is 0 to 20%, preferably 0 to 10%.
It is desirable that

The coating amount is determined by the hiding power of the coloring paint used,
Although it depends on coloring properties and is not determined unconditionally, it is usually 10
-100 g / m ² , preferably 30-70 g / m ² .

In order to dry the colored coating applied in this way, the same as in the case of the second undercoating, 8
Hot air of 0 to 100 ° C. may be applied for 5 to 10 minutes. Note that decoration such as printing for patterning may be further performed. <Photocurable Clear Coating> Next, in the present invention, the second base dried film surface 41, preferably, as shown in FIG.
The photocurable clear coating composition is applied by a (sponge) roll coater onto the surface of the first convex colored coating film 50 formed on the convex surface 40b of the base dried coating film, and is cured by light irradiation. A cured coating film 60 is formed.

The photocurable clear coating composition may be diluted with a non-reactive diluent, if necessary, to lower the coating viscosity.
It can also be applied to the entire surface of the uneven portion by spraying and then irradiated with light to obtain a photocured coating film.

When the photocurable clear coating composition is used after being diluted with a non-reactive diluent at the time of application of the photocurable clear coating composition, the diluent is heated from the surface to be coated with hot air or the like before light irradiation. Need to be scattered.

The hot air is heated at a temperature of 40 to 60 ° C. for 3 to 1
The application may be performed for 5 minutes, preferably 5 to 10 minutes. When the photocurable clear coating composition is used without being diluted with a non-reactive diluent, the hot air step is not required.

A cured coating film is obtained by irradiating the surface of the photocurable clear coating composition coated with light as described above. The irradiation light may be, for example, ultraviolet light, and a conventionally known irradiation method is employed. For example, a high-pressure mercury lamp 80 to 120 W / cm · 1 lamp, belt speed 2-1
Curing is possible at 0 m / min, preferably 3 to 7 m / min once.

The belt speed can be increased by increasing the number of lights. The coated plate cured by the light irradiation has good blocking resistance, and thus can be stacked and transported / stored without interposing an interleaving paper.

Further, in the present invention, the photocurable clear coating composition is overcoated on the surface of the undercoated acrylic emulsion enamel coating by applying a second undercoating or further a first convex coloring coating. As a result, a coating film having weather resistance for exterior use, high gloss, and high feeling of holding can be obtained.

[0043]

The inorganic decorative board finished with the photocurable clear coating according to the present invention is excellent in the stickiness of the coating film, long-term high gloss persistence, long-term weatherability, long-term adhesion, and long-term peeling resistance,
Excellent as an exterior material for outer walls and roofs.

Further, in the present invention, since the photocurable clear paint is overcoated on the surface of the acrylic emulsion enamel paint which has been undercoated, the topcoat paint can be instantaneously photocured and excellent in coating workability. In addition, a space such as a drying oven is not required, and a compact painting line is provided. No interleaving paper is required at the time of stacking, and industrial waste is reduced.

Since the obtained coated plate is hardly damaged, workability in on-site construction is also good.

[0046]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0047]

Example 1 <Step 1> Tile-patterned heavy calcium silicate plate (specific gravity: 1.2) having grooves (recesses) was heated to a plate surface temperature of 45 to 55 ° C. by a hot air dryer (hot air temperature: 100 ° C.). The temperature was raised, and an HDI isocyanate prepolymer (DC-371 manufactured by Nippon Polyurethane Co., Ltd.) was used as a sealer.
0): A mixture obtained by mixing and stirring water at a ratio of 100: 400 was applied to the surface by spraying at an amount of 100 g / m ² and dried with hot air (100 ° C.) for 2 minutes. <Step 2> Spray an acrylic emulsion enamel paint (manufactured by Chugoku Paint Co., Ltd./Hivisol L overcoat light gray) on the sealer coated plate obtained in the above step 1 by spraying.
It was applied in an amount of 50 g / m ² and dried with hot air (100 ° C.) for 5 minutes. <Step 3> An acrylic emulsion enamel paint (manufactured by Chugoku Paint Co., Ltd./Hivisol L overcoat beige) was passed through the protruding portion (except for the groove portion) of the coated plate obtained in the above step 2 with a sponge roll coater twice to obtain 50 g / m ² . And dried with hot air (100 ° C.) for 5 minutes.

Through the above-mentioned coating process, a coated plate having different hues in the grooves (concave portions) and the convex portions (other than the groove portions) was obtained. <Step 4> A urethane (meth) acrylate / photo-curable clear paint (manufactured by Chugoku Paint Co., Ltd./Aurex No. 280 Clear) on the convex portions (other than the groove portions) of the coated plate obtained in the above Step 3 Was applied in an amount of 30 g / m ^{2 by} one pass of a sponge roll coater. <Step 5> Apply the urethane (meth) acrylate / photocurable clear paint-coated plate obtained in the above step 4 to a UV irradiator (Western Trading Co., Ltd./
IST) High pressure mercury lamp 80w / cm, belt speed 5m / min.
A painted plate with a feeling of high flesh was obtained.

Various tests shown in Table 1 were performed on the coated plate 10 thus obtained. Table 1 shows the results.

[0050]

Comparative Example 1 Grooves (concave portions) and convex portions obtained in the same manner as in Example 1 except that only Steps 1 to 3 were carried out and Steps 4 to 5 were not carried out. The same test as in Example 1 was performed on the coated boards 100 having different hues (other than the groove portions).

Table 1 shows the results.

[0052]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of an inorganic decorative board having a photocurable clear coating finish according to the present invention, illustrating a process of manufacturing the inorganic decorative board shown in Example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of an inorganic decorative board according to a conventional example illustrating a process of manufacturing the inorganic decorative board shown in Comparative Example 1;

[Explanation of symbols]

10 ... Inorganic decorative board, 20 ... Inorganic porous base material 20a ... Surface recess of inorganic porous substrate, 20b ... Inorganic porous base material ,... The entire surface of the inorganic porous base material, 30... The first undercoat film composed of a sealer or the like, 31... The entire surface of the first undercoat film, 40... A second base (colored) coating film formed by applying an acrylic emulsion enamel paint, 40a..., Convex portions (projection surface) of the second base coating film, 40b. The concave portion (the concave portion surface) of the second base coating film, 50... The first convex portion coating film formed by applying an acrylic emulsion enamel paint, 50 b... The surface of the first convex portion coating film, 60. ····· Photocured clear coating film, 100 ··· Painted and finished inorganic decorative board according to Comparative Example 1.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Kenji Miyakawa 2306, Mikami, Yasu-cho, Yasu-gun, Shiga Prefecture Within China Paint Co., Ltd. (72) Koji Morimoto, inventor Koji Morimoto, Yasu-cho, Yasu-gun, Shiga 2306 Mikami 7 China Paint Co., Ltd. F term (reference) 4D075 AE03 BB46Z CA13 CA32 CB04 DA06 DB12 DC02 EA13 EA21 EB22 EB38 EB45 4J038 FA151 FA251 FA261 FA281 JA33 JC18 KA03 KA12 NA03 NA10 NA11 NA23 PA13 PC14 PC17 PC05 PC08

Claims (4)

[Claims] 1. A photocurable (meth) acrylate compound (a) and a photopolymerization initiator (b), wherein at least one surface of an inorganic decorative plate undercoated with an acrylic emulsion enamel paint is provided.
An inorganic decorative board coated with a photocurable clear coating film formed from a photocurable clear coating composition containing: 2. The photocurable (meth) acrylate compound
The inorganic decorative board according to claim 1, wherein (a) is a photocurable urethane (meth) acrylate compound. 3. A photo-curable (meth) acrylate compound is applied to at least one surface of an inorganic decorative board, which is undercoated with an acrylic emulsion enamel paint. (c) applying a photocurable clear coating composition containing (a) and a photopolymerization initiator (b), and then curing the coated surface of the photocurable clear coating composition by irradiating light. Of inorganic decorative board finished with transparent clear coating. 4. Photocurable (meth) acrylate compound (a)
Is a photocurable urethane (meth) acrylate compound. The method for producing an inorganic decorative board according to claim 3, wherein