JP3527568B2 - How to paint building boards - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating method for forming a pattern on the surface of a building board such as an outer wall material and a roof material made of an inorganic material.

[0002]

2. Description of the Related Art This type of building board is a finished product by applying an undercoating and then an overcoating, but in order to improve the design, the topcoating has conventionally been used as the primary coating. A coating method of forming a pattern by performing a secondary coating of a color different from that of the primary coating was also provided as one of the finish coating methods.

[0003]

In the above coating method, mixing occurs between the coating film of the primary coating and the coating film of the secondary coating, and the pattern of the secondary coating bleeds or the surface of the secondary coating film There was a problem that the primary coating film was raised. In particular, in the case of a high-density building board such as a roofing material having a bulk specific gravity of 1.3 or more, since the surface of the building board is dense, the paint is difficult to permeate, and such a problem remarkably appears. Therefore, conventionally, in order to prevent mixing between the primary coating film and the secondary coating film, the secondary coating film is applied after the coating film of the primary coating film is almost completely cured. However, such a method has a problem that the coating process is lengthened and the productivity is lowered.

[0004]

As a means for solving the above-mentioned conventional problems, the present invention provides an emuljo on the surface of a building material.
Facilities strainer primary coating by emission coating, primary coating according to the primary coating is in the coating method of straining facilities secondary coating by emulsion paint uncured state, glass transition of the secondary coating
The transition point is set at 3 ° C or more lower than the glass transition point of the primary coating.
All SANYO are constant, and the primary coating and the secondary coating to provide a method of coating a unique building board, the coating method of the present invention is particularly paint bulk density 1.3 or more dense building board Useful for.

Examples of building boards to which the present invention is applied include inorganic boards such as calcium silicate board, slag cement perlite board, wood chip cement board, precast concrete board, ALC board, gypsum board, and slate roof tile. It is not limited to these, as long as it is a building board that is normally used for building, the building board is particularly preferably applied to a ceramic-based exterior material or an inorganic roof tile, but the application is to these It is not limited. The building board may have a smooth flat surface, but it is more preferable that the unevenness is formed on the surface thereof by means of embossing or the like.

The building board to which the present invention is advantageously applied has a bulk specific gravity (according to the test method of JIS A 5418) of 1.3.
There are high-density building boards above. Since the surface of the high-density building board is dense, as described above, it is difficult for the paint to penetrate, and the primary coating film dries slowly. For example, when an acrylic resin emulsion paint is applied to the surface of a building board having various bulk specific gravities at a rate of 100 g / m ² , the drying time is as shown in the table below. That is, when the bulk specific gravity of the building board is 1.3 or more, the drying property becomes significantly slow. Therefore, in the prior art, the coating process is very long in such a high-density building board because the secondary coating is performed after the primary coating is seen to be almost completely dried.
Therefore, by applying the present invention, the coating process can be shortened regardless of the density of the building board.

On the other hand, the slow drying of the coating film on the high density building board is also an advantage. In the case of low-density building boards, the coating film easily penetrates, but due to slight variations in surface density,
The penetrability of the coating film, that is, the drying property varies. Therefore, especially when the surface of the building board is embossed, the flow rate of the coating film into the embossed recesses increases at a place where the coating film dries slowly, and to the embossed recesses of the coating film at a place where the coating film dries quickly. Flow into the building board is reduced, causing uneven painting on the surface of the building board. However, since the coating film on the high-density building board dries slowly, it becomes substantially uniform over the entire surface, and therefore the amount of flow into the embossed recesses becomes substantially uniform, so that uneven coating is unlikely to occur on the building board surface. Therefore, when the present invention is applied to such a high-density building board, the coating process can be shortened and uniform coating can be performed.

The paint used in the coating of the present invention is mainly a paint using an acrylic resin emulsion as a vehicle, and the acrylic resin emulsion is a carbon of acrylic acid or methacrylic acid (both of which are referred to as (meth) acrylic acid). Number 1 to 8 alkyl ester, for example, methyl (meth) acrylate, ethyl (meth) acrylate,
Homopolymers of (meth) acrylic acid ester monomers such as propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and octyl (meth) acrylate, or these One or two of these copolymers or these (meth) acrylic acid ester monomers and other copolymerizable monomers, for example, styrene, vinyltoluene, (meth) acrylonitrile, vinyl chloride, vinyl acetate, butadiene, and other vinyl monomers. Or more, and if desired, (meth) acrylic acid, itaconic acid, fumaric acid, (meth)
2-hydroxyethyl acrylate, (meth) acrylic acid 2
Hydroxypropyl, glycidyl (meth) acrylate,
It is a copolymer emulsion with one or more functional monomers such as (meth) acrylamide and N-methylol (meth) acrylamide, and the acrylic resin emulsion usually contains the above monomers alone or a mixture of two or more of the above monomers. For example, higher alcohol sulfate (Na salt or amine salt), alkylallyl sulfonate (Na salt or amine salt), alkyl naphthalene sulfonate (Na salt or amine salt), alkyl naphthalene sulfonate salt condensate, alkyl phosphate , Rosin soap, anionic surfactant such as fatty acid salt (Na salt or amine salt), polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl Min, polyoxyethylene alkylol amine, polyoxyethylene alkyl amide,
Nonionic surfactants such as sorbitan alkyl ester, polyoxyethylene sorbitan alkyl ester, octadecyl amine acetate, imidazoline derivative acetate, polyalkylene polyamine derivative or salt thereof, octadecyl trimethyl ammonium chloride,
Surfactants such as cationic surfactants such as trimethylaminoethyl alkylamide halogenide, alkylpyridinium sulfate, and alkyltrimethylammonium halogenide, and ammonium persulfate, potassium persulfate, sodium perborate, hydrogen peroxide, permanganate Potassium or a redox polymerization catalyst in which sodium sulfite, sodium bisulfite, sodium hyposulfite, ferric chloride, sodium ascorbate, etc. are combined with potassium, 2,2'-azobis [2- (N-phenylamidino) propane ] Water-soluble such as dihydrochloride, 2,2'-azobis {2- [N- (4-chlorophenyl) -amidino] propane} dihydrochloride or water-soluble azo polymerization initiator, etc. It is produced by emulsion polymerization using a polymerization initiator. The molecular weight of the acrylic resin of the acrylic resin emulsion is usually 50,000 to 300,000, preferably 100,000 to 200,000, and the film tensile strength is 60 kg / cm ² or more.
For that purpose, it is desirable that the minimum film forming temperature is 30 ° C. or higher.

The acrylic resin emulsion may be a room temperature dry type, a thermosetting type, or a room temperature curing type. The acrylic resin emulsion may be ultramarine blue, dark blue, red iron oxide, iron oxide yellow, carbon black, titanium oxide, iron powder, carbonic acid. Calcium, magnesium carbonate,
Barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, zinc oxide, alumina, silica, diatomaceous earth, dolomite, gypsum,
Pigments and fillers such as talc and clay, and, if desired, silica sand with an average particle diameter of about 0.1 mm to 1.5 mm, cold water sand, glaze fired particles, glass beads, quartz powder, aggregates such as plastic powder, ethylene Wetting agents such as glycol, propylene glycol and glycerin, thickening agents such as sodium polyacrylate and carboxymethyl cellulose, curing agents such as urea resins, melamine resins, phenol resins, epoxy resins, zinc oxide, metal complex salts and hydrazide compounds, or crosslinking. Agents, other leveling agents, viscosity improvers, defoamers, ultraviolet absorbers, anti-aging agents, etc. are appropriately added and kneaded to obtain a paint. The pigment and / or aggregate is usually added in an amount of 25 to 100 parts by weight based on 100 parts by weight of the solid content of the acrylic resin emulsion.

In the present invention, first, the above paint is sprayed on a building board surface by a spray gun, a roll coater, a flow coater,
Apply the primary coating using a coating machine such as a knife coater. Prior to the primary coating, an undercoat coating may be applied to the surface of the building board. For the undercoat coating, the same one as the synthetic resin emulsion used for the primary coating is used.
At this time, the thickness of the coating film is usually 5 to 200 μm in a dry state.

If desired, after the above-mentioned primary coating, a secondary coating is carried out through a heating process in the same manner by using one or two or more coatings different in color from the coating of the primary coating.
In this case, the secondary coating is applied in a state in which the coating film formed by the primary coating is uncured (undried in the case of a room temperature drying type, uncured and / or undried in the case of a curing type). The uncured state referred to in the present invention means from immediately after coating to touch-drying. The glass transition point Tg (2) of the synthetic resin of the coating material used in the secondary coating film, that is, the secondary coating material by the above-mentioned secondary coating is the glass transition point Tg (2) of the synthetic resin material of the coating material used in the primary coating material, that is, the primary coating material. Set lower than 3 ) by 3 ℃ or more. It goes without saying that when the coating film is curable, Tg (1) and Tg (2) are the Tg of the coating film in the uncured state.

Usually, the primary coating is applied to the entire surface of the building board, and the secondary coating is partially applied to the surface of the building board, for example, in a predetermined pattern. In this case, it is possible to partially protect the surface of the building board that has been subjected to the primary coating with a masking sheet, etc., and then apply the secondary coating. It is also possible to apply a secondary coating of a desired pattern by controlling the operation pattern and spray time of one or more spray guns by a computer.

After secondary coating, it is at room temperature or usually 100 to 1
The primary coating film and the secondary coating film are dried and / or cured by performing heat treatment at 50 ° C. for about 10 to 15 minutes. In this way, a pattern is formed on the primary coating film by one or two or more secondary coating films having different colors.

[0014]

In the present invention, the surface of the building board is coated with emulsion paint.
The primary coating by the primary coating order to painting since straining facilities secondary coating in the uncured state (undried) I, shortens an interval between the primary coating and secondary coating, it is shortened coating process time . Then, the Tg (2) of the secondary coating is set to the Tg of the primary coating.
Since lower set 3 ° C. or higher than g (1), the secondary coating becomes softer than the primary coating, in the coating of small dense building board bulk specific gravity of 1.3 or more water permeability even , It becomes difficult to mix with the primary coating film during the secondary coating, and the phenomenon that the pattern due to the secondary coating film is bleeding or the primary coating film is not projected on the surface of the secondary coating film is eliminated.

[0015]

EXAMPLE An acrylic resin emulsion was used as an undercoat on the surface of an inorganic flat roof tile having a thickness of 6 mm and a bulk specific gravity of 1.3 (according to the test method of JIS A 5418) whose surface has been embossed, and dried. The original plate for painting. A top coat paint A is applied to the above-mentioned base plate for coating with a flow coater at a coating amount of 100 g / m ² to perform a primary coat. Secondary coating is performed by partially spray-applying the top-coat paint B of the same color with an air spray. The amount of secondary coating applied is 30 g / m ² . Then, it dried at 120 degreeC for 12 minutes, and obtained the final product. Table 1 shows the physical properties of the obtained product such as finished appearance and adhesion.

The composition of the above-mentioned top coating composition is as follows.

[0017]

[Table 1]

Referring to Table 1, in the case of Comparative Example 1 in which Tg (1) and Tg (2) are equal and Comparative Example 2 in which Tg (2) is higher than Tg (1), the bleeding of the secondary coating film is caused. Mixing of the primary coating and the secondary coating,
Leaching of the primary coating occurs on the surface of the secondary coating, but Tg (2)
It is clear that in the case of Examples 1, 2 and 3 in which is lower than Tg (1), there is no mixing of the primary coating film and the secondary coating film and a clear pattern can be obtained by the secondary coating film.

[0019]

EFFECTS OF THE INVENTION According to the present invention, it is possible to apply a coating having an extremely high designability in which a picture is formed clearly on the primary coating film by the secondary coating film in a short time.

─────────────────────────────────────────────────── --- Continuation of the front page (56) Reference JP-A-55-159875 (JP, A) JP-A-5-123639 (JP, A) JP-A-6-345563 (JP, A) JP-A-56- 14492 (JP, A) JP 56-28679 (JP, A) JP 53-141369 (JP, A) JP 57-56393 (JP, A) JP 62-79875 (JP, A) Japanese Patent Publication 47-27769 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B05D 1/00-7/26 C09D 1/00-10/00 C09D 101/00-201 / Ten

Claims (2)

(57) [Claims] 1. A facilities strainer an <br/> following painting by an emulsion paint building material surface, the primary coating according to the primary coating is in the coating method of straining facilities secondary coating by emulsion paint uncured state, the The glass transition point of the secondary coating is the primary coating
Is set at 3 ° C or more lower than the glass transition point of the above, and the primary coating and the secondary coating are different colors, which is a coating method for building boards. 2. The building board is a high-density building board with a specific gravity of 1.3 or more.
A method for coating a building board according to claim 1.