JP2008246340A - External facing material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an external facing material the surface of which has a clear coating film that is free from whitening or foaming and has a thin and uniform film thickness and is excellent in weather resistance. <P>SOLUTION: The external facing material is formed to have a sealer coating film 2, an enamel coating film 3, and the clear coating film 4 in sequence on a base material 1. The clear coating material used to form the clear coating film 4 is an acrylic emulsion coating material. A resin solid component is 20-33 mass% and the viscosity of the coating material is 5-80 mPa s when coated with the clear coating material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to exterior materials such as outer wall materials used in buildings.

  In order to provide weather resistance, a clear coating film is provided on the surface of a conventional exterior material by applying and drying a clear paint (see, for example, Patent Document 1).

However, in order to form a thin clear coating on the surface, it is necessary to reduce the amount of the clear coating applied. However, if a pattern with unevenness is formed on the surface of the exterior material, the film thickness of the clear coating It was difficult to make the film thin and uniform. Although it is possible to form a thin film without diluting the coating amount by diluting the clear paint with water, etc., the large amount of water used for dilution facilitates foaming during drying and the clear coating film becomes white. Or it takes a long time to dry.
JP 2005-47967 A

  The present invention has been made in view of the above points, and it is an object of the present invention to provide an exterior material having a clear coating film formed on the surface thereof, which is free from whitening and foaming, has a thin and uniform film thickness, and is excellent in weather resistance. It is what.

  An exterior material according to claim 1 of the present invention is an exterior material formed by providing a base material 1 with a sealer coating 2, an enamel coating 3, and a clear coating 4 in this order, and the clear coating 4 The clear paint used for forming is an acrylic emulsion paint, the resin solid content at the time of application of the clear paint is 20 to 33% by mass, and the viscosity of the paint is 5 to 80 mPa · s. It is.

  According to the exterior material according to claim 1 of the present invention, it is possible to form on the surface a clear coating film which is free from whitening and foaming, has a thin and uniform film thickness and is excellent in weather resistance.

  Embodiments of the present invention will be described below.

  FIG. 1 shows an example of an embodiment of the present invention, and this exterior material is formed by providing a baser 1 with a sealer coating 2, an enamel coating 3, and a clear coating 4 in this order.

  The base material 1 may be either an inorganic material such as a ceramic base material or a metal base material, or an organic material such as a resin base material. The exterior material of the ceramic base material is used for applications such as tiles and outer wall materials. The ceramic base material is prepared by blending an inorganic filler, a fibrous material, etc. into a hydraulic glue used as a raw material for an inorganic hardened body, and curing and curing it. As a hydraulic glue, Although not particularly limited, for example, one or more selected from Portland cement, blast furnace cement, blast furnace slag, calcium silicate, gypsum and the like can be used. In addition, as the inorganic filler, fly ash, microsilica, silica sand, etc., and as the fibrous material, inorganic fibers such as pulp and synthetic fibers, and metal fibers such as steel fibers are used alone or in combination. Can be used. Molding can be performed by methods such as extrusion molding, cast molding, papermaking molding, press molding, etc., and after molding, autoclave curing, steam curing, room temperature curing as necessary, and ceramics used as exterior materials A system substrate can be produced. In addition, as the base material 1, for example, an inorganic board such as a flexible board, a calcium silicate board, a gypsum slag perlite board, a wood piece cement board, a precast concrete board, an ALC board, or a gypsum board can be used.

  In addition, as the sealer coating used to form the sealer coating film 2, a permeable type undercoat made of a low molecular weight resin or a small particle size emulsion can be used. Specifically, for example, an acrylic emulsion resin was prepared by adding a pigment such as titanium oxide, an iron oxide pigment, carbon black, calcium carbonate, an additive such as butyl cellosolve or an antifoaming agent, water, and the like to stir and disperse. Things can be used as sealer paints.

  In addition, as the enamel paint used to form the enamel coating film 3, it is possible to use a colored paint that has a high background concealing power, is excellent in durability, has a wide variety of colors, and can contribute to improvement in appearance design. it can. Specifically, for example, pigments such as titanium oxide, iron oxide pigments, carbon black, barium sulfate, additives such as butyl cellosolve, antifoaming agents, thickeners, water, etc. are added to acrylic emulsion resin, and dispersed by stirring. What was prepared in this way can be used as an enamel paint.

  The clear paint used to form the clear coating film 4 is an acrylic emulsion paint. As the acrylic emulsion paint, it is preferable to use an aqueous paint such as an acrylic resin paint based on an acrylic emulsion or an acrylic silicone resin paint based on an acrylic silicone emulsion in order to reduce environmental burden. The acrylic emulsion paint preferably contains aggregates such as acrylic beads and mica. Thereby, the designability can be improved.

  Furthermore, the resin solid content at the time of painting a clear paint is 20 to 33% by mass, and the paint viscosity is 5 to 80 mPa · s. When the resin solid content at the time of applying the clear paint is less than 20% by mass, the film thickness of the clear paint film 4 becomes non-uniform, the clear paint film 4 is whitened, and the weather resistance of the clear paint film 4 is lowered. On the contrary, when the resin solid content exceeds 33% by mass, the film thickness of the clear coating film 4 becomes non-uniform, and the clear paint is liable to foam, and the clear coating film 4 has foam. It is what happens. The resin solid content means the solid content of the acrylic emulsion resin contained in the clear paint. On the other hand, when the viscosity of the clear coating is less than 5 mPa · s, the film thickness of the clear coating 4 becomes non-uniform, the clear coating 4 is whitened, and the weather resistance of the clear coating 4 is further improved. On the contrary, when the viscosity of the paint exceeds 80 mPa · s, the film thickness of the clear coating film 4 becomes non-uniform, and the clear paint tends to foam, and the clear coating film 4 has foam. It is what happens.

In manufacturing an exterior material as shown in FIG. 1, first, a sealer coating is applied to the surface of the substrate 1 and dried to form a sealer coating 2 for sealing the substrate 1 and ensuring adhesion. Form. At this time, the sealer coating is preferably applied to the surface of the substrate 1 at an application amount of 32 to 76 g / m ² . And it is preferable to perform baking drying on 80-140 degreeC and the conditions for 1-3 minutes, for example using a jet dryer. The sealer coating can be applied using a spray gun, roll coater, flow coater, curtain coater, or the like.

Next, an enamel coating is applied to the surface of the sealer coating 2 and dried to form an enamel coating 3 for coloring or the like. At this time, the enamel paint is preferably applied to the surface of the sealer coating 2 at a coating amount of 76 to 140 g / m ² . And it is preferable to perform baking drying on 80-120 degreeC and the conditions for 1-3 minutes, for example using a jet dryer. The enamel coating can be applied using a spray gun, roll coater, flow coater, curtain coater or the like.

Thereafter, a clear coating is applied to the surface of the enamel coating 3 and dried to form a clear coating 4. At this time, the clear paint is preferably applied to the surface of the enamel coating film 3 at an application amount of 32 to 76 g / m ² . And it is preferable to perform baking drying on 80-140 degreeC and the conditions for 1-3 minutes, for example using a jet dryer. If the baking and drying are not performed sufficiently, the durability of the exterior material may be easily lowered depending on environmental conditions such as temperature and humidity. The clear paint can be applied using a spray gun, roll coater, flow coater, curtain coater, or the like.

  In the exterior material manufactured as described above, the resin solid content at the time of painting of the clear paint forming the clear coating film 4 is 20 to 33% by mass, and the paint viscosity is 5 to 80 mPa · s. Even if a pattern with unevenness is formed on the surface of the substrate 1, the clear coating film 4 is formed on the surface with no whitening / foaming, uniform film thickness, and excellent weather resistance. It is something that can be done. Moreover, the clear coating film 4 can be formed as thin as about 10 to 15 μm.

  Hereinafter, the present invention will be specifically described by way of examples.

(Base material)
As the base material, a ceramic base material prepared as follows was used. That is, first, 40 parts by mass of ordinary Portland cement, 40 parts by mass of fly ash, 6 parts by mass of pulp, and 14 parts by mass of pulverized cement board waste material are mixed, and water is mixed so that the solid content concentration becomes 20% by mass. A cement slurry was prepared by dispersing the mixture. Next, after making this cement slurry, press forming was performed to form a pattern, and a papermaking plate having a concavo-convex pattern was produced. The papermaking plate was steam-cured at 60 ° C. for 10 hours, and further autoclaved at 170 ° C. for 5 hours to produce a ceramic base material.

(Sealer paint)
As the sealer paint, 25 parts by mass of acrylic emulsion resin, 20 parts by mass of pigment (consisting of titanium oxide, iron oxide pigment, carbon black, calcium carbonate), 1 part by mass of additives (consisting of butyl cellosolve and antifoaming agent), What was prepared by adding 54 parts by mass of water and stirring and dispersing it was used.

(Enamel paint)
As for the enamel paint, 28 parts by mass of acrylic emulsion resin, 23 parts by mass of pigment (made of titanium oxide, iron oxide pigment, carbon black, barium sulfate), additive (made of butyl cellosolve, antifoaming agent, thickener) A product prepared by adding 6.5 parts by mass and 42.5 parts by mass of water and stirring and dispersing it was used.

(Clear paint)
As clear paint, 34 parts by mass of acrylic emulsion resin, 1.7 parts by mass of additives (consisting of butyl cellosolve, benzotriazole UV absorber, antifoaming agent, thickener, hindered amine antioxidant), 64.3 water An aqueous acrylic emulsion paint prepared by adding parts by mass and stirring and dispersing was used. And by changing the water in this water-based acrylic emulsion paint appropriately, water-based acrylic emulsion paints of specifications 1 to 7 having different resin solid content and paint viscosity were prepared as shown in [Table 1] below.

(Exterior material)
The packaging materials of Examples 1 to 3 and Comparative Examples 1 to 4 were manufactured as follows.

First, a sealer coating was applied to the surface of the substrate and dried to form a sealer coating. At this time, the sealer coating was applied to the surface of the substrate at an application amount of 54 g / m ² . The baking drying was performed using a jet dryer at 120 ° C. for 1.5 minutes. Next, an enamel coating was applied to the surface of the sealer coating and dried to form an enamel coating. At this time, the enamel coating was applied to the surface of the sealer coating at a coating amount of 98 g / m ² . The baking drying was performed using a jet dryer at 120 ° C. for 2 minutes. Then, the exterior material as shown in FIG. 1 was manufactured by apply | coating and drying a clear paint on the surface of an enamel coating film, and forming a clear coating film. At this time, the clear paint was applied to the surface of the enamel coating film at an application amount of 54 g / m ² . The baking drying was performed using a jet dryer under the conditions of 130 ° C. and 60 seconds. In addition, application | coating of each coating material was performed using the spray gun.

  Moreover, the exterior material of Comparative Example 5 was produced in the same manner as described above except that a clear coating film was not formed.

  And the following characteristics were evaluated about the exterior material obtained as mentioned above.

(Uniformity of clear coating film thickness)
The film thickness of the clear coating film was measured, “◯”: the film thickness was within the range of 8 to 20 μm, “Δ”: the film thickness was within the range of 5 to 30 μm, “× ": Uniformity of the film thickness of the clear coating film was evaluated based on the criteria that the film thickness is less than 5 μm or the film thickness is more than 30 μm.

(Clear coating whitening)
The surface of the exterior material is visually observed. “○”: No cloudiness or swelling can be confirmed at all. “△”: Slight cloudiness or swelling is observed. “×”: Clearly cloudy or swelling is observed. The whitening of the clear coating film was evaluated based on the criteria.

(Clear film foam / foam)
Observe the surface of the exterior material using a magnifying glass with a magnification of 20 times. “○”: No foaming or foaming can be confirmed, “△”: Independent foaming / foaming, “×”: Continuous foaming・ Evaluation of foaming / foaming of clear coating film based on the standard of foaming.

(Weatherability)
In Okinawa Prefecture, the exterior material was installed at an inclination of 20 ° to the south, and an exposure test was conducted for 3.5 years. The color difference (ΔE) was measured using a color difference meter “CR-400” manufactured by Konica Minolta Holdings. And, “◯”: the color difference within 2 years after exposure for 3 years, “△”: the color difference between 2 and 4 within 3 years exposure, “×”: the exposure for 3 years The weather resistance was evaluated by determining that the color difference exceeded 4. The results are shown in [Table 2] below and FIG.

It is sectional drawing which shows an example of embodiment of this invention. It is a graph which shows the result of an exposure test.

Explanation of symbols

1 Base material 2 Sealer coating 3 Enamel coating 4 Clear coating

Claims (1)

  It is an exterior material formed by providing a sealer coating, an enamel coating, and a clear coating in this order on a substrate, and the clear coating used to form the clear coating is an acrylic emulsion coating, An exterior material having a resin solid content of 20 to 33% by mass and a coating viscosity of 5 to 80 mPa · s when a clear paint is applied.

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