JP2610085C - - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating and finishing method, and more particularly to a coating and finishing method capable of forming a multilayer coating film having a good finished appearance and high durability. It relates to a suitable paint finishing method. 2. Description of the Related Art Conventionally, a multi-layer finish coating for finishing a decorative uneven pattern using a coating material such as an undercoat material, a main material, and a topcoat material is generally used for painting a building wall or the like. It is being done. Examples of such a finish coating method include a synthetic resin emulsion-based multilayer finishing method and a cement-based or polymer cement-based multilayer finishing method, depending on the type of the main material for pattern formation. The former usually comprises a four-layer coating film using a sealer, an undercoat material, a main material, and a topcoat material. The sealer improves the adhesion between the base material and the undercoat layer. The main material is to form a three-dimensional pattern on the finished surface, and the top coating material is to be coated for the purpose of providing aesthetics and durability. Such a method has an advantage that a highly designable pattern having a large change in unevenness can be formed. However, there are many coating steps, and there are problems in terms of cost and construction period. [0003] On the other hand, the latter method is usually used to form a three-layer coating film using a sealer, a cement-based main material, and a topcoat material, and is advantageous because it requires one step less than the former method. However, since ordinary cement-based coating materials are hard and have poor elasticity, the coating film cannot follow cracks generated on a base material surface such as a building wall surface, and thus, a crack occurs in a top coating film. was there. If such cracks are left, rainwater or carbon dioxide gas will enter from the cracks, causing corrosion of the reinforcing steel of the building and accompanying concrete peeling. In addition, since it is a coating material using cement as a binder, a mixture of water / cement and a synthetic resin emulsion / cement hardens in 1 to 4 hours, so it is necessary to prepare a necessary amount each time, which is very difficult in terms of material management. It takes time and effort. Further, when mixing the liquid / powder, the cement is easily scattered and "as powder" is liable to appear in the mixture, so that there are many problems in operation. Further, in the coating material, the skin of the coating film formed due to the presence of large particles in the cement powder is rough, and even when the top coat is applied on the surface, the rough surface is not spread and the pattern does not have a smooth pattern, There is a problem that the final finished appearance is inferior. SUMMARY OF THE INVENTION [0004] The present invention further simplifies the conventional coating process to form a two-layer structure, has a good finished appearance, and follows cracks on the substrate surface. It is an object of the present invention to provide a paint finishing method capable of forming a highly durable coating film. Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, after applying a paint having a specific composition and a fine elasticity, a top coat is applied. As a result, it was found that a highly durable coating film having a good finished appearance was obtained, and the present invention was completed. That is, the present invention provides an aqueous dispersion of a carbonyl group-containing copolymer (A), a hydrazide compound (B) containing at least two or more hydrazide groups per molecule as a crosslinking agent, and a pigment ( C), and the pigment has a volume concentration of 4 in the mixture.
After applying a coating material for an elastic base having an elongation percentage of 0 to 55% and a formed coating film having an elongation percentage of 30 to 150% in a 20 ° C atmosphere, the elongation percentage of the formed coating film is set to 20 ° C atmosphere The present invention provides a paint finishing method for applying a top coat of not more than 150%. The method of the present invention can use a one-pack type aqueous emulsion paint having a specific pigment concentration and microelasticity as a base paint, so that it can follow cracks and the like on the base material surface, Conventional sealer coating + primer coating (+ pattern coating) because it can form a coating layer with excellent adhesion to old coatings, etc., and toughness and elastic lasting power.
The functions of each step can be integrated into one, and by applying a top coat on the base coating film, a good finished appearance can be obtained and the coating step can be simplified. Hereinafter, the present invention will be described in detail. The coating material for elastic base used in the method of the present invention comprises an aqueous dispersion of a carbonyl group-containing copolymer (A), a hydrazide compound having at least two or more hydrazide groups per molecule as a crosslinking agent (B), and a pigment. An aqueous emulsion paint containing (C). The aqueous carbonyl group-containing copolymer aqueous dispersion (A) comprises (a) a polymerizable carbonyl group-containing monomer having at least one carbonyl group in one molecule.
1 to 30% by weight, (b) monoolefinically unsaturated carboxylic acid having 3 to 5 carbon atoms, unsaturated carboxylic acid amide, N-alkyl and / or N-alkylol of the same unsaturated carboxylic acid amide 0 to 10% by weight of a monomer selected from the group consisting of a derivative and a monoolefinically unsaturated carboxylic acid, and (c) a vinyl aromatic compound, an n-alkyl ester of acrylic acid having 1 to 8 carbon atoms, Methacrylic acid n-alkyl esters having 1 to 8 carbon atoms, vinyl esters of saturated carboxylic acids, 1,3
A monomer mixture containing 60 to 99.9% by weight of a monomer selected from the group consisting of diene, tertiary butyl acrylate, vinyl halide, ethylene, acrylonitrile and methacrylonitrile, Those easily obtained by emulsion copolymerization in the presence can be suitably used. As the monomer (a), a monomer having a polymerizable double bond having at least one carbonyl group in one molecule is used. Specific examples of the monomer (a) include agrolein, diacetone acrylamide, diacetone methacrylamide, formylstyrene, and vinyl alkyl ketone having 4 to 7 carbon atoms (
Examples thereof include vinyl methyl ketone, vinyl ethyl ketone, and vinyl butyl ketone). Particularly preferred are diacetone acrylamide and diacetone methacrylamide. The hydrazide compound (B) having at least two or more hydrazine residues per molecule used as the crosslinking agent includes (d) a dihydrazide compound represented by the following general formula, H ₂ N—NH—CO— It is produced by reacting a polymer having (CH ₂ ) _n —CO—NH—NH ₂ (n ≦ 8) and / or (e) a carboxylic acid ester group with hydrazine or hydrazine hydrate (that is, hydrazine hydroxide). (See Japanese Patent Publication No. 52-22878). The polymer having a carboxylic acid ester group is obtained by adding an unsaturated monomer such as styrene, divinylbenzene or isobutylene to an ester of an unsaturated carboxylic acid such as acrylic acid, methacrylic acid or itaconic acid with a lower alcohol. Those obtained by copolymerization are suitable. The use ratio of the carbonyl group-containing aqueous copolymer dispersion (A) and the hydrazide compound (B) is based on 1 mol of the carbonyl group of the copolymer contained in the aqueous copolymer dispersion (A). On the other hand, the proportion of the hydrazide residue in the hydrazide compound is preferably 0.02 to 3 mol, preferably 0.1 to 2 mol. Further, as the pigment (C) used in the coating material for the elastic base, for example, coloring pigments such as titanium oxide, carbon black and red iron oxide, calcium carbonate, talc, mica, clay, diatomaceous earth, silica sand, pearlite, etc. Extender pigments and aggregates, etc.,
It can be appropriately selected and used. The pigment (C) is blended so as to have a pigment volume concentration (hereinafter may be abbreviated as “PVC”) in a mixture of the components (A) and (B) of 40 to 55%. Need to be Here, “pigment volume concentration (PVC)” is a volume ratio of the pigment to the solid content of the mixture, and is obtained from the following equation. ☆ [Equation 1] If the above PVC is less than 40%, the resulting elastic base coating film has a poor feeling of holding, resulting in poor base adjustment ability, while if the PVC content exceeds 55%, the resulting elastic base coating film has a high density. When the top coat is overcoated, unevenness of the top coat paint is likely to occur and a good finished appearance is not obtained, and the physical properties of the base coating film itself are also deteriorated. In the present invention, the elongation of the coating film formed by the above-mentioned coating material for elastic base is 20%.
It is necessary to be 30 to 150%, preferably 40 to 140% in an atmosphere of ° C. Here, the elongation percentage of the coating film is a value measured at a stretching speed of 200 mm / min at 20 ° C. using a universal tensile tester with a thermostat (manufactured by Shimadzu Corporation, Autograph AG2000B type). The sample was prepared according to JIS-A-6910. If the elongation percentage is less than 30%, the resulting coating film for the elastic base cannot sufficiently follow cracks on the substrate surface, while if it exceeds 150%, the type of topcoat paint to be applied over the coating film In some cases, cracks may occur in the overcoat film, which is not preferable. The above-mentioned paint for an elastic base may further contain a surfactant, a dispersant, an antifoaming agent, a thickener, a film-forming aid, a preservative, an antifreezing agent, an organic solvent, etc., if necessary. An agent can be compounded. The top coat used in the method of the present invention has an elongation percentage of a formed coating film of 150 ° C. in a 20 ° C. atmosphere.
% Or less, preferably 5 to 100%, without any particular limitation, water-based or organic solvent-based coatings which can impart coloring and gloss to the finished surface, weather resistance, waterproofness and the like can be applied without any particular limitation. Examples of such a top coat include those mainly containing acrylic resin, acrylic / urethane resin, polyurethane resin, fluorine resin, silicon / acrylic resin, and the like. [0022] If the elongation exceeds 150% in the top coat, the stain resistance of the top coat surface is reduced, and the aesthetic appearance is impaired, which is not preferable. [0023] In the coating finishing method of the present invention, an appropriate base material surface is coated with the elastic base coating material using a known coating tool such as a roller, an air spray, an airless spray, a ricin gun, a universal gun, and a brush. A base coat layer is formed, and then the top coat is coated on the coated surface with the same coating equipment as above to form a top coat layer. The substrate that can be used is not particularly limited, and examples thereof include a concrete surface, a mortar surface, a straight plate, a PC plate, an ALC plate, a concrete block surface, wood, stone, plastic, and metal. It is preferable that the bases of these are appropriately adjusted. [0025] In the present invention method, coating thickness of the elastic base paints, 0.3~1.5kg / m ² based on the coating amount, preferably is 0.5~1.3kg / m ² suitably . It is preferable that the coating is applied so as to form a smooth surface or a smooth uneven surface (a pattern such as citron skin or crater) over the entire surface of the substrate. The amount of the top coat applied is suitably about 0.1 to 0.5 kg / m ² . According to the coating finishing method of the present invention, the coating material for the elastic base applied in the first step has excellent adhesion to the substrate surface, and the formed microelastic coating film itself is very small. It is tough enough to follow the cracks on the substrate surface, so that the conventional coating process can be simplified, and since the base coating has a function as a buffer between the substrate and the top coating, it has low elongation. Even if a hard type top coat is used, a coat having a good finished appearance can be obtained without cracking of the top coat. EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples. Unless otherwise noted,
All parts are parts by weight. Preparation Example of Aqueous Emulsion Preparation Example 1 312 parts of deionized water and Newcol 707S were placed in a two-liter four-necked flask.
2.3 parts of F (manufactured by Nippon Emulsifier, solid content 30%) was added, and the mixture was replaced with nitrogen and kept at 80 ° C. Immediately before dropping the pre-emulsion having the following composition, 0.7 parts of ammonium persulfate was added, and the pre-emulsion was dropped over 3 hours. Deionized water 338 parts Diacetone acrylamide 32 parts Acrylic acid 3.2 parts Styrene 97 parts Methyl methacrylate 260 parts 2-ethylhexyl acrylate 100 parts n-butyl acrylate 150 parts Newcol 707SF 62 parts Ammonium persulfate 1.2 parts After dropping, From 30 minutes, a solution prepared by dissolving 0.7 part of ammonium persulfate in 7 parts of deionized water for 30 minutes is added dropwise, and the temperature is maintained at 80 ° C. for further 2 hours, and then the temperature is reduced to about 40 to 60 ° C. And adjust the pH to 8-9 with emulsion (A).
) -1 was obtained. Production Example 2 Emulsion (A) -2 was obtained in the same manner as in Production Example 1 except that the pre-emulsion to be dropped had the following composition. Deionized water 315 parts Diacetone acrylamide 74 parts Acrylic acid 3.9 parts Styrene 105 parts Methyl methacrylate 269 parts 2-ethylhexyl acrylate 105 parts n-butyl acrylate 176 parts Hydroxyethyl acrylate 15 parts Newcol 707SF 49 parts Ammonium persulfate 1.5 parts The ammonium persulfate added after the completion of the reaction was a solution in which 0.8 part was dissolved in 8 parts of deionized water. The properties of the emulsions (A) -1 and (A) -2 obtained in Production Examples 1 and 2 are shown in Table 1. [Table 1] (Note 1) The solid content was calculated by heating a sample at 150 ° C. for 30 minutes and measuring the remaining amount. Preparation of Paint for Elastic Base Ingredients such as adipic dihydrazide were added to the emulsion obtained in the above Production Example.
In the combinations and amounts shown in Table 1 and mixed by stirring to obtain each coating material for elastic bases. Table 2 shows the characteristic values of each paint. Note that (Note 2) to (Note 6) in Table 2 are as follows. (Note 2) Extender: using calcium carbonate with a specific gravity of 2.7 (Note 3) Thickener: 2.5% hydroxyethylcellulose (Note 4) Defoamer: "SN Deformer A63" (manufactured by San Nopco) 5) Dispersant: "Nopco Santo K" (manufactured by San Nopco) (Note 6) Elongation percentage (%) of formed coating film: A test piece was prepared according to JIS-A-6910, and the elongation of the dried coating film The rate was measured using a tensile tester Autograph AG2000B type (manufactured by Shimadzu Corporation) in a 20 ° C. atmosphere at a tensile speed of 200 mm / min. [Table 2] Examples and Comparative Examples Each of the elastic base paints prepared as described above was adjusted to an appropriate coating viscosity with water, and then applied to a mortar plate (90 × 300 × 20 mm) with an airless spray at an amount of about 0.9 kg /. m
² and dried at 20 ° C. and 75 RH% for 1 day. Next, various top coats were applied on each base coat in the combinations shown in Table 3, and the amount of coating was about 0 by airless spray.
. It was coated to ² kg / m ² and dried at 20 ° C. and 75 RH% for 7 days to obtain a painted plate. Table 3 shows the performance test results of these coated plates. The top coats (* 1) to (* 6) in Table 3 are as follows. (* 1) Alesletan white: polyurethane resin-based solvent-based topcoat, Kansai Paint Co., Ltd., elongation 40% (20 ° C.) (* 2) Alestyle Top S White: acrylic resin-based solvent-based topcoat, Kansai Paint Co., Ltd. , Elongation 15% (20 ° C.) (3) Alesflon White: Fluororesin-based solvent-type top coating, Kansai Paint Co., Ltd.
Elongation rate 50% (20 ° C) (* 4) Ares silicone white: Acrylic silicone resin-based solvent-based paint, a product of Kansai Paint Co., Ltd., elongation rate 15% (20 ° C) Acrylic resin-based water-based paint, product of Kansai Paint Co., Ltd., elongation 20% (20 ° C.) (* 6) Ares Rubber Tex White: Acrylic resin-based water-based paint, product of Kansai Paint Co., elongation 400% (20 ° C.) ☆ [Table 3] The performance tests in Table 3 are as follows. (Note 7) Finished appearance: The finished appearance of the surface of a coating film formed on a mortar plate of 300 × 300 × 50 mm by the methods of Examples and Comparative Examples was visually evaluated. A sample that was uniformly and smoothly finished without unevenness was rated as “O”, and a sample that was unfinished evenly due to spread of the ground surface or unevenness was evaluated as “X”. (Note 8) Resistance to repeated warming / cooling action: According to JIS-A-6910, the coated plate was immersed in water at 20 ° C for 18 hours, immediately cooled in a constant temperature bath at -20 ° C for 3 hours, Then, the mixture is heated in a thermostat at 50 ° C. for 3 hours. After repeating this operation for 24 hours as one cycle ten times, the coated surface was visually observed and evaluated according to the following criteria. ：: No peeling, cracks, blisters, etc., and no significant discoloration and gloss reduction. ×: There is at least one of the above defects (Note 9) Weather resistance: The coated surface was exposed to the outdoors for 12 months, the coated surface was washed with water, and the coating surface condition and stain resistance were visually observed and evaluated according to the following criteria. The test coated plate was installed so as to be perpendicular to the bottom surface. (Painted surface condition) ：: No peeling, cracks, blisters, etc., and no significant discoloration and gloss reduction. ×: There is at least one of the above defects. (Stain resistance) ○: Almost no stain is observed. Δ: Stain is observed but not conspicuous. X: Stain is remarkable.

Claims (1)

Claims: 1. A carbonyl group-containing copolymer aqueous dispersion (A) on a substrate surface, and a hydrazide compound (B) containing at least two or more hydrazide groups per molecule as a crosslinking agent. And the pigment (C), and the volume concentration of the pigment in the mixture is from 40 to
After applying an elastic base paint having an elongation percentage of 55% and an elongation percentage of the formed coating film of 30 to 150% in a 20 ° C atmosphere, the elongation percentage of the formed coating film is 150% in a 20 ° C atmosphere. %, Which is characterized by applying a top coat of not more than 10%.