JPS5914428B2 - Manufacturing method of colored cement tiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 30. The present invention relates to a method for manufacturing colored cement roof tiles with excellent weather resistance and other properties.

In recent years, with the trend toward prefabricated housing and lower costs, the use of cement tiles has rapidly increased in place of traditional Japanese and Western tiles due to their ease of construction and manufacturing cost advantages35, and demand is expected to continue to grow in the future. It is expected that

Cement roof tiles are manufactured by mixing cement, hard fine aggregate, water, etc., forming the mixture under pressure, and curing it for a long period of time to harden it. Although such cement tiles are sometimes used as they are, in recent years they have been mostly colored to give them a more luxurious appearance. A common coloring method is to apply a colored paint made of one-component acrylic or two-component acrylic urethane resin to the surface of a hardened cement tile. However, such polymeric materials have the drawback of high raw material costs, and furthermore, they often cause discoloration and peeling phenomena, and are therefore not satisfactory. On the other hand, a colored cement with water or a white cement with colored pigments and water is applied to form a colored layer and cured, and then, if necessary, a transparent paint made of a polymeric material is applied on top of it. However, methods to create a sense of luxury are also being considered. However, these methods also have drawbacks such as discoloration such as efflorescence, insufficient adhesion with the colored layer on the cement tile, and problems such as crack peeling. Furthermore, in order to prevent efflorescence and discoloration of the colored cement tiles mentioned above and to impart durability, a top coat such as a solvent-based paint or a water-based paint may be applied. It is difficult to prevent efflorescence unless the time after application of the colored layer and the application of the topcoat is not properly selected.Furthermore, if a long period of time has passed after the topcoat is applied, distortion may occur between the colored layer and the topcoat. The adhesion of the adhesive deteriorates, often causing problems such as blistering, cracking, and peeling. Furthermore, water-based emulsion paint containing cement is deposited on the inner wall of the cup due to the centrifugal force of the electrostatic force, making it difficult to atomize the paint, making it impossible to use electrostatic painting.

Therefore, conventionally, air spray or airless spray painting methods have been used, but it is not possible to paint complex areas such as flat tiles and decorative tiles, and areas that are difficult to spray, and the number of spray guns required is significantly reduced. It was necessary to add more parts or make some adjustments later. As mentioned above, there are various defects in the performance and application of conventional cement tile coating methods and coating materials used, and there are also defects in coating.

SUMMARY OF THE INVENTION In view of the prior art as described above, it is an object of the present invention to provide an excellent method for applying a colored coating to cement roof tiles. In particular, in the present invention, a cement-containing emulsion paint is electrostatically applied to a hardened cement tile, and an emulsion paint is applied as a top coat electrostatically, thereby achieving a relatively thick film thickness and excellent adhesion to the hardened cement tile. The objective is to form a coating with excellent coating properties.

These purposes are (a) (1) acrylic acid or methacrylic acid ester copolymer emulsion resin (ester is an alkyl group having 1 to 8 carbon atoms) or copolymerization emulsion resin of the acrylic acid or methacrylic ester and styrene ( Styrene content: 30% by weight or less) Solid content: 20-80% by weight (J
i) Bisphenol type epoxy emulsion resin solid content
...0.5 to 4% by weight (IlI
) Filler: 20 to 80% by weight (
V) Cement (20μ blue residue 10% or less)...
...4 to 20% by weight (V) colored pigment ...
...0.1 to 15% by weight and 0.8 to 1.2 equivalent of the epoxy emulsion resin of a polyamide resin curing agent,
Furthermore, if necessary, it consists of small amounts of various additives, and [(i
}I-(Ii)]/0'S7) weight ratio is 2.0 to 9.
100 parts by weight of the mixture in the range of 0 and (b)
Paint composition A with a viscosity of 10 to 30 seconds (measured with a food cup 464: 200C) obtained by kneading 70 to 300 parts by weight of water is applied to the surface of a hardened cement tile that has been preheated to a surface temperature of 40 to 70°C to a dry film thickness. Electrostatically coated to a thickness of 40 to 300μ, after drying to the touch,
Further, if necessary, after heating at a low temperature, (c) (1) acrylic acid or methacrylic acid ester copolymer emulsion resin (ester is an alkyl group having 1 to 8 carbon atoms) or copolymerization of the acrylic acid or methacrylic ester and styrene. Emulsion resin (styrene content is 30% by weight or less) Solid content: 55-95% by weight (I
i) Filler: 0 to 15% by weight
(Jii) Colored pigment...0.1-1
5% by weight, and 100 parts by weight of a mixture consisting of small amounts of various additives as necessary, and (d) 60 to 200 parts by weight of water, to obtain Acrylic Noleage Resin Paint Composition B, with a dry film thickness of 10 to 100 parts by weight. This is achieved by a method for manufacturing colored cement tiles, which is characterized by electrostatically coating the tiles to a thickness of 50μ and drying.

An alkyl ester monomer having 1 to 8 carbon atoms of acrylic acid, an alkyl ester monomer having 1 to 8 carbon atoms of acrylic acid, which is a component constituting the acrylic acid or methacrylic ester copolymer emulsion resin used in coating composition A. Alkyl esters include methyl, ethyl, n-butyl, isobutyl, tert-butyl 2-
Ethylhexyl, benzyl, propyl, isopropyl,
Sec-butyl etc. are typically used. Esters having 9 or more carbon atoms are unsuitable for the synthesis of emulsion resins for cement admixture because gels are generated during emulsion polymerization and emulsion particles become highly hydrophobic. or,
Copolymer emulsion resins of these acrylic acid (or methacrylic acid) esters and styrene are also used, but
If styrene is used in an amount of 30% by weight or more, the weather resistance of the resulting emulsion coating film will be significantly reduced, making it undesirable for use as an outdoor emulsion resin that requires durability. Particularly preferred acrylic acid or methacrylic acid esters are methyl methacrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and when styrene is used, it is particularly preferably 20% by weight or less.
Furthermore, if necessary, it is also possible to copolymerize several weight percent of a functional monomer such as acrylic acid or 2-hydroxyethyl methacrylate. Since the acrylic acid (or methacrylic acid) ester copolymer emulsion resin or the copolymerization emulsion resin of acrylic acid (or methacrylic acid) ester and styrene used in the present invention is mixed with cement,
It is best to use materials that have alkali resistance and excellent cement mixing stability. For this purpose, alkylphenol polyethylene ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyethylene glycol oleyl ether, etc. are recommended as emulsifiers during emulsion polymerization. ethers; esters such as sorbitan alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyglycol fatty acid ester; nonionic surfactants such as polypropylene glycol polyethylene glycol polymer, polyoxyethylene alkylamide, polyoxyethylene alkylamine, etc. Even when used alone or in combination with an anionic surfactant, it is necessary to use a large amount of nonionic surfactant and anionic surfactant in a small amount. Advantageously, the molecular weight of these acrylic emulsion resins is from 50,000 to 300,000, preferably from 100,000 to 200,000. Further, the film forming temperature is preferably 0 to 30 DEG C. If it exceeds 30 DEG C., the cured coating film becomes too hard and tends to cause cracks, which is not preferred. These resins are blended in the mixture a at a solid content of 20 to 80% by weight. If the resin content is less than 20% by weight, the concentration in the coating composition will be too low and the coating film surface formed by the resin floating up due to the difference in specific gravity with the filler, cement, and coloring pigment will become porous and dense. Due to the lack of properties, efflorescence is likely to occur.Furthermore, since the resin component is small, the coating lacks flexibility and tends to cause cracks and peeling phenomena in the coating film after a long period of time. On the other hand, if the resin content exceeds 80% by weight, the hardening of the cement and the resin will be delayed and sufficient strength of the coating film will not be obtained, resulting in a decrease in the water resistance of the coating film. The preferred blending ratio of the resin is 30 to 60% by weight. The bisphenol type epoxy emulsion resin used in coating composition A is an aromatic diglycidyl ether obtained from bisphenol A and epichlorohydrin, and has an average molecular weight of 350.
~1000 resin is made into a water-dispersed type using an emulsifier, and the resin solid content is 0.5% in the mixture A.
~4% by weight is used.

If the resin content is less than 0.5% by weight, the adhesion with the substrate will be reduced, and if it exceeds 4% by weight, the weather resistance of the formed coating film will be significantly reduced. The preferred blending ratio of the resin is 1 to 3% by weight. Examples of fillers used in coating composition A include inorganic particulate materials such as calcium carbonate, barium sulfate, magnesium carbonate, talc, and clay.

This optical filler is blended to improve brittleness and increase the amount, and is preferably kneaded to a particle size of 50 μm or less. If it exceeds 50 μm, it is not preferable because during electrostatic coating, deposits due to centrifugal force on the inner wall of the electrostatic force drop become significant and atomization becomes poor.

The optical filler is blended in the above mixture a in a proportion of 20 to 80% by weight. This is because within this range, the effect of improving the density, brittleness, durability, etc. of the coating film is large, and more preferably the content is 30 to 60% by weight. Cement used in paint composition A includes portland cement, blast furnace cement, silica cement,
An example is alumina cement, but it is necessary to use fine particle cement with a particle size of 20 μ and a blue residue of 10% or less. If the 20μ blue residue exceeds 10%, the centrifugal force causes a significant accumulation on the inner wall of the electrostatic tube during electrostatic coating, and atomization becomes extremely poor.

In the method of the present invention, cement is blended in the above-mentioned mixture a in a proportion of 4 to 20% by weight. 4 cement
If it is less than % by weight, the hardness of the coating film will not be improved sufficiently and the adhesion to the base will decrease. On the other hand, if the cement content exceeds 20% by weight, the moisture required for cement hardening will not be sufficiently supplied and the hydration reaction will not proceed sufficiently, making it impossible to obtain a dense and hard coating film and causing efflorescence. Becomes easily brittle.
The coloring pigment used in the coating composition A is typically a general inorganic pigment, but depending on the color 3, an organic pigment having alkali resistance and weather resistance may be used. For example, when coloring black, use carbon black, iron oxide, etc., for red color, use Bengara, etc., for green color, use chromium oxide, etc.
In the case of blue, examples include cyanine blue and the like, and in the case of white, titanium dioxide and the like can be cited. The colored pigment is preferably kneaded to a particle size of 50 μm or less. If it exceeds 50μ, deposits due to centrifugal force on the inner wall of the electrostatic force drop during electrostatic coating will be significant, resulting in poor atomization, which is not preferable.

In the method of the present invention, the coloring pigment is blended in the mixture A at a ratio of 0.1 to 15% by weight, and by blending within this range, sufficient coloring can be achieved. Examples of additives used in the coating composition A include dispersants, antifoaming agents, thickeners, preservatives, and antifungal agents to improve pigment dispersibility, painting workability, storage stability, etc. Examples include film-forming aids for improving the film-forming properties of dovetail coatings.

As the curing agent for epoxy resins used in coating composition A, polyamide resins obtained by polycondensation of diamines or diamine derivatives and dibasic acids or dibasic acid derivatives are used. It is necessary to use the polyamide resin in an amount of 0.8 to 1.2 equivalents based on the epoxy group of the epoxy resin. If the amount is less than 0.8 equivalents or more than 1.2 equivalents, the original properties of the epoxy resin, such as adhesion and flexibility, will be significantly reduced, and other performances such as durability will also be deteriorated, which is not preferable.

Furthermore, in coating composition A, the solid content of (1) acrylic acid (or methacrylic acid) ester copolymerized emulsion resin or copolymerized emulsion resin of acrylic acid or (methacrylic acid) ester and styrene in mixture a;
i) The sum of the solid content of the epoxy emulsion resin and (V
) The weight ratio with cement is [(:)+(11)]AV)1.

If this ratio is less than 2.0, the weather resistance of the coating film,
Adhesion deteriorates and efflorescence occurs, making it impossible to form a thick film with good paint film performance.On the other hand, if this ratio is greater than 9.0, the adhesion of the paint film is poor. , hardness is insufficient and thick films cannot be formed. Coating composition A used in the present invention is prepared by blending 70 to 300 parts by weight of water to 100 parts by weight of the above mixture (a) and having a coating viscosity of 10.
~30 seconds (measured at Foudkap Falls 4: 20°C).

This is because within this range, cement hardening and painting workability are good. Next, as the emulsion resin used in the acrylic resin emulsion coating composition B used as the top coating in the present invention, the acrylic acid or methacrylic ester copolymer emulsion resin used in the coating composition A (ester has 1 to 8 carbon atoms)
or a copolymer emulsion resin of acrylic acid or methacrylic acid ester and styrene (styrene content is 30% by weight or less).

However, since the emulsion resin is used for top coating, it is particularly preferable that the minimum film forming temperature (MFT) is 30 to 60°C. If the MFT is lower than 30°C, contamination such as adhesion of dust during the summer season will be significant, whereas if it is higher than 60°C, film forming properties will be insufficient and cracks will easily occur, which is not appropriate. In addition, the present inventors have used vinyl acetate emulsion resins such as vinyl acetate resin, vinyl acetate-acrylic resin, ethylene monovinyl acetate resin, or styrene-butadiene emulsion resin, which are typically used in the coating industry. We also investigated emulsion resins that are used in
It was found that the alkali resistance was poor, the long-term durability was poor, and the latter had poor weather resistance, all of which were found to be unsuitable for the present invention.

The emulsion resin is blended in the above mixture (c) at a solid content of 55 to 95% by weight. Examples of fillers used in acrylic resin emulsion coating composition B include extender pigments such as calcium carbonate, barium sulfate, magnesium carbonate, talc, and clay. This filler is preferably kneaded to a particle size of 50 μm or less;
If it exceeds μ, deposits due to centrifugal force will be significant on the inner wall of the electrostatic tube during electrostatic coating, and atomization will be poor, which is not preferable. The filler is blended in the above mixture (c) in a proportion of 0 to 15% by weight. Further, as the coloring pigment, inorganic pigments and organic pigments similar to those used in the above-mentioned coating composition A can be used.

The coloring pigment is blended in the mixing sacrifice c) in a proportion of 0.1 to 15% by weight. If the amount of fillers and color pigments exceeds the above range, the gloss of the finished coating film will decrease and the efflorescence prevention effect of the coating film will also decrease, which is not preferred.

The acrylic resin emulsion coating composition B may further contain additives such as a dispersant, a preservative, a fungicide, and an ultraviolet absorber, if necessary.

The acrylic resin emulsion coating composition B used in the present invention is made of 6 parts by weight of water per 100 parts by weight of the above mixture (e).
It is blended in an amount of 0 to 200 parts by weight.

The coating composition A as described above is coated with a surface temperature of 4.
It is applied to the surface of cement tiles that have been preheated to 0-70°C.

As an electrostatic coating method, an electrostatic coating machine with a rotating electrostatic force is suitable, with a voltage of 60 to 90 KV and a rotation speed of 2,000.
~5,000R. P. M:C', preferably equipped with a sweeping air device. In addition, during electrostatic coating, water or water and a water-soluble solvent (for example, butyl cellosolve) or a water-soluble solvent can be supplied (sprayed) to the inside or outside of the rotating electrostatic force spout continuously or intermittently. Accumulation and drying of paint on the outer wall can be prevented, and long-term continuous electrostatic painting performance can be improved. In addition, a disc-type electrostatic coating machine can also be used. The film thickness is 40 to 300 in dry film thickness.
μ is preferably 80 to 150 μ. In the method of the present invention, by using the above-mentioned specific paint composition, it is possible to perform electrostatic painting with good electrostatic spray characteristics without causing the accumulation of paint components on the inner wall of the electrostatic force tube. .
Coating composition A is applied, and after drying, acrylic resin emulsion coating composition B is overcoated. The coating method is the same as in the case of coating composition A. Furthermore, if the surface temperature of the tile is preheated to 30 to 60°C before applying the acrylic resin emulsion coating composition B, the drying of the coating film of the acrylic resin emulsion coating composition B can be accelerated and the armpits may be This is preferable because it can be prevented. In the method of the present invention, the applied coating film is dried naturally or by heating.

In the method of the present invention as described above, since the coating composition contains an epoxy resin and cement as components, it is possible to obtain a dense and hard coating film with excellent adhesion to the cement tile to be coated.
The coating film does not flow even under summer sunlight conditions and has good adhesion to the top coat.

Furthermore, in the method of the present invention, the resin component of the coating composition A is sufficiently dispersed in the filler to densify the coating film, prevent efflorescence, and improve durability against water, heat and ultraviolet rays. Discoloration and peeling of the paint film can be prevented, and the top coat B can be applied satisfactorily. The present invention will be explained below with reference to Examples.

In the Examples, parts and % are parts by weight and % by weight, respectively. , Example [Undercoat paint composition] 1) Acrylic emulsion resin Solid content...40 parts Bisphenol type epoxy emulsion resin Solid content (average molecular weight 600)...2 Talc (average particle Diameter 30μ) ・・・・・・20 Calcium carbonate (
Average particle size 10μ)...21 parts carbon black
...Titanium oxide (average particle size 10μ) ...2 Cement (20μ blue residue 5% or less) ...10 Polyamide resin curing agent ...22
) Additive ゛゜゜゛゜゜2 Water ・・・・・・１
501) Methyl methacrylate, butyl acrylate, 2-ethylhexyl acrylate and styrene (20:8:
8:4), average molecular weight 150,000, minimum film formation temperature 20
°C copolymer.

2) A mixture consisting of a preservative, a dispersant, an antifreeze agent, a film forming aid, and an antifoaming agent.

The viscosity of this undercoat paint composition was 18 seconds (measured using a food cup rotor 4: 2'C).

<Top coating composition> 3) Acrylic emulsion resin Solid content...90 parts Carbon black...0.5 titanium oxide (average particle size 10μ)...1.5 calcium carbonate ( Average particle size 10μ) ・・・・・・2 additives
...6 water
...1003) Methyl methacrylate,
Butyl acrylate and styrene (50:30:10)
A copolymer with an average molecular weight of 150,000 and a minimum film formation temperature of 40°C.

The undercoat composition was kneaded and dispersed to a thickness of 40 μm or less, and electrostatically applied (cup type; 3000 μm) to a hardened cement tile preheated to a surface temperature of 60° C. to a dry film thickness of approximately 100 μm.
RPM; 80KV; Shaping air pressure 1.5kg/
d) did. After drying to the touch, the surface temperature of the tile was heated to 40 ° C., and the above-mentioned top coat composition was kneaded and dispersed to a thickness of 20 μm or less, and electrostatically coated (under the same conditions as the above-mentioned undercoating) to a dry film thickness of about 30 μm. Then, it was dried by heating at 880° C. for 15 minutes. The obtained electrical film is smooth, has good adhesion, weather resistance,
Durability etc. were good. Furthermore, the coating properties of the electrostatic coating were good, and the coating properties of hidden areas were also good.

In addition, in the above-mentioned undercoat paint composition, 2
When using 40% 0 μ blue residue, in Seiden painting, the electrostatic force builds up on the inner wall of the paint, which causes poor atomization, makes continuous painting impossible, and makes it impossible to obtain a uniform film thickness, and also causes paint loss. It was a lot.

Claims (1)

[Scope of Claims] 1 (a) (i) Acrylic acid or methacrylic acid ester copolymer emulsion resin (ester is an alkyl group having 1 to 8 carbon atoms) or a copolymerization emulsion of the acrylic acid or methacrylic acid ester and styrene. Resin (styrene content is 30% by weight or less) Solid content: 20 to 80% by weight (ii) Bisphenol type epoxy emulsion resin solid content: 0.5 to 4% by weight (iii) Filler... ...20-80% by weight (iv) cement (20
10% or less of sieve residue)...4 to 20% by weight (v) Coloring pigment...0.1 to 15% by weight and 0.8 to 1.2% of the epoxy emulsion resin 100 weight of a mixture consisting of an equivalent amount of a polyamide resin curing agent and a small amount of various additives as necessary, and the weight ratio of [(i)+(ii)]/(iv) is in the range of 2.0 to 9.0. and (b) Coating composition A having a viscosity of 10 to 30 seconds (measured with food cup No. 4: 20°C) obtained by kneading 70 to 300 parts by weight of water was preheated to a surface temperature of 40 to 70°C. Electrostatically coat the hardened cement tile surface to a dry film thickness of 40 to 300 μm, dry to the touch, and if necessary, heat at a low temperature.
ester is an alkyl group having 1 to 8 carbon atoms) or a copolymer emulsion resin of the above acrylic acid or methacrylic ester and styrene (styrene content is 30% by weight or less)
Solid content: 55-95% by weight (ii) Filler: 0-15% by weight (iii)
Coloring pigment: Acrylic resin emulsion paint obtained by kneading 100 parts by weight of a mixture consisting of 0.1 to 15% by weight and small amounts of various additives as necessary, and (d) 60 to 200 parts by weight of water. A method for producing a colored cement tile, which comprises electrostatically coating Composition B to a dry film thickness of 10 to 50 microns and drying. 2. The minimum film forming temperature of the copolymerized emulsion resin constituting acrylic resin emulsion coating composition B is 30 to 6.
The manufacturing method according to item 1, characterized in that the temperature is 0°C. 3. The manufacturing method according to item 1, which comprises applying coating composition A, drying to the touch, heating the surface temperature of the tile to 30 to 60°C, and then overcoating acrylic resin emulsion coating composition B. .