JPH1121514A - Water-based flat coating material and process for finish coating therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a water-based flat coating material useful for coating the inner and outer walls of a building and to provide a process for finish coating whereby a double layer having a good flat finish appearance and high durability can be formed by using the same. SOLUTION: This material is prepared by adding a pigment component containing a flatting agent to a resin dispersion containing an emulsion of a carbonyl-containing copolymer having a Tg of -30 to 15 deg.C and a polyhydrazide compound having at least two hydrazide groups in the molecule in an amount to give 0.02-3.0 equivalents, per carboxyl group of the emulsion particles, hydrazide groups so that the formed mixture may have a pigment volume concentration of 25-40 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous matting paint which is particularly useful for coating the inside and outside walls of a building, and to form a multi-layer having a good matte finish appearance and high durability using the same. The present invention relates to a paint finishing method capable of performing the following.

[0002]

2. Description of the Related Art A water-based matting paint conventionally used in architectural painting has a high pigment concentration of generally 50 to 70%.
Therefore, elongation and breaking strength are small.

In general, in interior / exterior finishing, a multi-layer finish coating for finishing a decorative uneven pattern using a coating material such as a (base coating material) main material and a top coating material is generally performed. The main material is usually an organic filler having an intermediate coating function, and a coating film of the coating material expands and contracts due to heat and moisture in an outdoor environment. Therefore, when a paint having a high pigment concentration and a low elongation or breaking strength is applied thereon, the formed overcoat film cannot follow the deformation of the undercoat film, resulting in cracks and peeling. Yes, such conventional water-based matte paints could not be used outdoors.

[0004]

Means for Solving the Problems The inventors of the present invention have intensively studied to solve the above-mentioned problems and to cope with outdoor multi-layer finishing, and as a result, by using a specific emulsion, limiting the pigment concentration, The inventors have found that a matte coating film having sufficient hiding properties and excellent durability can be formed even at a low pigment concentration, and the present invention has been completed.

That is, according to the present invention, the Tg is -30 to 15 ° C.
And the polyhydrazide compound having at least two hydrazide groups in one molecule (B) are prepared by mixing the hydrazide group with the carbonyl group in the emulsion particles. Is contained in a resin dispersion containing 0.02 to 3.0 equivalents of a pigment (C) containing a matting agent so that the pigment volume concentration in the coating composition becomes 25 to 40%. And a coating finish method comprising applying an undercoat on a surface to be coated and applying the aqueous matte paint as a top coat thereon.

Hereinafter, the present invention will be described in detail.

In the present invention, the carbonyl group-containing copolymer emulsion (A) preferably contains 0.1 to 30% by weight of the carbonyl group-containing monomer (a) in the monomer composition. a) 0.1 to 30% by weight of a carbonyl group-containing monomer, (b) 0 to 10% by weight of a water-soluble monomer copolymerizable with the monomer (a), and (c) other monomers A monomer mixture containing 60 to 99.9% by weight of
A copolymer emulsion obtained by emulsion polymerization in the presence of a dispersant can be suitably used.

The above monomer (a) is a monomer having at least one carbonyl group in one molecule, and specific examples thereof include acrolein, diacetone acrylamide, diacetone methacrylamide, formylstyro-
And vinyl alkyl ketones having 4 to 7 carbon atoms (eg, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone) and the like. Of these, diacetone acrylamide and diacetone methacrylamide are particularly preferred.

Examples of the monomer (b) include unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid and crotonic acid; styrenesulfonic acid sodium salt, sulfoethyl methacrylate and its sodium salt and ammonium. Salts; unsaturated carboxylic acid amides such as (meth) acrylamide and dimethylaminopropyl (meth) acrylamide; and dimethylaminoethyl (meth) acrylate.

Examples of the monomer (c) include vinyl aromatic compounds such as styrene and vinyltoluene; methyl (meth) acrylate, ethyl (meth) acrylate,
Alkyl having 1 to 24 carbon atoms of (meth) acrylic acid such as propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and lauryl (meth) acrylate; Cycloalkyl esters; hydroxyalkyl esters of (meth) acrylic acid having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth) acrylate; N-vinylpyrrolidone, ethylene, butadiene, chloroprene, vinyl acetate, (meth) Acrylonitrile and the like.

The above copolymer has a Tg (glass transition temperature).
Is in the range of -30 to 15 ° C, preferably -15 to 0 ° C. The Tg of the copolymer can be calculated from the following equation using the glass transition temperature of a homopolymer of a monomer as each copolymer component.

1 / Tg = W ₁ / T ₁ + W ₂ / T ₂ +...
+ Wn / Tn where Tg is the glass transition temperature (absolute temperature) of the copolymer, W ₁ , W ₂ ,..., Wn are the weight fractions of the monomers,
T ₁ , T ₂ ,..., Tn are glass transition temperatures (absolute temperatures) of the respective homopolymers. When the Tg is lower than −30 ° C., the coating film becomes tacky and the stain resistance is reduced, while it exceeds 15 ° C. In such a case, a large shrinkage stress acts on the coating film in a low-temperature environment, and cracks and peeling occur, which is not preferable.

In the present invention, the polyhydrazide compound (B) having at least two hydrazide groups in one molecule includes, for example, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide,
Saturated aliphatic carboxylic acid dihydrazides having 2 to 18 carbon atoms such as adipic acid dihydrazide, sebacic acid dihydrazide; monoolefinically unsaturated dicarboxylic acid dihydrazide such as maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide; carbonic acid dihydrazide; Bisemicarbazide; a polyfunctional semicarbazide obtained by excessively reacting hydrazine or the above-mentioned dihydrazide with a polyisocyanate compound (Japanese Patent Application Laid-Open No. Hei 8-1513)
No. 58, and JP-A-8-283377).

The content of the polyhydrazide compound (B) is such that the amount of the hydrazide group is 0.02 to 3.0 equivalents, preferably 0.1 to 2.0 equivalents to 1 equivalent of the carbonyl group in the emulsion particles. It is an equivalent amount.

As the vehicle component of the present invention, a resin dispersion containing the emulsion (A) and the polyhydrazide compound (B) alone may be used. For example, a vinyl acetate emulsion, an acrylic resin emulsion, a vinyl acetate-acryl emulsion, an ethylene-vinyl acetate emulsion, or the like may be blended in such an amount that the solid content in the total vehicle component is 50% by weight or less.

In the present invention, the pigment (C) includes, for example, coloring pigments such as titanium oxide, carbon black and red iron oxide; calcium carbonate (tancar), talc, mica, and the like.
Examples include extenders such as clay, diatomaceous earth, silica sand, and pearlite, and aggregates, which can be appropriately selected and used. In particular, diatomaceous earth can be used as a matting agent.

The pigment (C) has a pigment volume concentration (hereinafter sometimes abbreviated as "PVC") of 2 in the paint.
It must be blended so as to be 5 to 40%, preferably 30 to 35%. Here, “pigment volume concentration (PVC)” is a volume ratio of the pigment to the solid content of the mixture of the resin and the pigment, and is obtained from the following equation.

[0018]

(Equation 1)

If the PVC is less than 25%, the matte effect and hiding power of the coating film become insufficient, while if the PVC exceeds 40%, the elongation and the breaking strength of the coating film become small, and It is not preferable because it cannot follow the deformation and cracks or peels off the coating film.

The paint of the present invention may further contain, if necessary, a surfactant, a dispersant, an antifoaming agent, a thickener, a film-forming aid, a preservative,
Additives for paints such as antifreezing agents and organic solvents can be blended.

In the method of finishing the coating of the present invention, the surface to be coated is undercoated, and the above-mentioned water-based matting paint of the present invention is applied thereon as a topcoat.

The surface to be coated is, for example, a material surface such as a concrete surface, a mortar surface, a slate plate, a pearlite plate, a stone material, wood, paper, plastic, metal, etc. One coated with a primer for improving the adhesion may be used. As the primer, conventionally known water-based or organic solvent-based paints containing a resin as a main component such as acrylic, styrene-acryl, vinyl chloride, vinyl chloride-vinyl acetate, and ethylene-vinyl acetate can be used. .

As the undercoating, a conventionally known elastic material which forms a smooth surface or a three-dimensional texture and is used for the purpose of following cracks or the like on the substrate surface can be applied without any particular limitation. Examples of the elastic material include a main material for multi-layer finishing such as a synthetic resin emulsion system, a cement system, and a polymer-cement system, and a base adjustment coating material. In particular, a carbonyl group-containing copolymer emulsion (D) and a pigment ( A paint containing E) having a pigment volume concentration of 3
0-70% and the elongation of the formed coating film is 3
A coating for an elastic base having a content of 0% or more, preferably 30 to 150%, is desirable from the viewpoints of following cracks and the like on the substrate surface and cracking resistance and finish of a matte coating film as an overcoat. .

The carbonyl group-containing copolymer emulsion (D) is appropriately selected from the monomers containing a carbonyl group-containing monomer described in the description of the emulsion (A) used in the paint of the present invention. A copolymer emulsion obtained by subjecting the monomer mixture to emulsion polymerization in the presence of a dispersant can be used. In the emulsion,
If necessary, the dihydrazides described in the description of the polyhydrazide compound (B) may be appropriately added. The pigment (E) can be appropriately selected from the pigments described in the description of the pigment (C) used in the paint of the present invention. In the above-mentioned elastic base coating material, if the pigment volume concentration is less than 30%, the resulting coating film has a poor feeling of holding and the base adjustment ability decreases, while if it exceeds 70%, the denseness and physical properties of the coating film decrease. This is not desirable because unevenness in suction of the top coating material occurs. Also, the elongation of the formed coating film is 20 ° C.
If the content is less than 30% in the atmosphere, the ability to follow the surface to be coated becomes insufficient, which is not desirable.

In the method of the present invention, the undercoat paint and the paint of the present invention can be applied using known coating equipment such as a roller, an air spray, an airless spray, a ricin gun, a universal gun, and a brush, respectively. The coating amount of the undercoat is 0.2 to 1.5 kg / m ² , preferably 0.3 to 1.5 kg / m ² .
1.3 kg / m ² , 0.1 to 0.5 kg / top coat
m ² , preferably in the range of 0.2 to 0.4 kg / m ² .

[0026]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. “Parts” and “%” are “parts by weight” respectively.
And "% by weight".

Preparation of Aqueous Emulsion Production Example 1 312 parts of deionized water, N
ewcol707SF (manufactured by Nippon Emulsifier Co., Ltd., surfactant,
2.3 parts (solid content 30%) was added, and after the replacement with nitrogen, the temperature was maintained at 80 ° C. Immediately before the dropwise addition of the pre-emulsion having the following composition, 0.7 part of ammonium persulfate was added, and the pre-emulsion was added dropwise over 3 hours. .

Deionized water 338 parts Diacetone acrylamide 32 parts Acrylic acid 6 parts Styrene 97 parts Methyl methacrylate 149 parts 2-ethylhexyl acrylate 100 parts n-butyl acrylate 258 parts Newcol 707SF 62 parts Ammonium persulfate 1 .2 parts 30 minutes after the completion of the dropwise addition, a solution prepared by dissolving 0.7 parts of ammonium persulfate in 7 parts of deionized water was added dropwise for 30 minutes.
After maintaining the temperature at 80 ° C. for further 2 hours and then lowering the temperature to about 40 to 60 ° C., the pH was adjusted to 8 to 9 with aqueous ammonia to obtain Emulsion A. Emulsion A has a solid content of 50.2
%, PH 8.2.

Production Examples 2 to 5 Emulsions B to E were obtained in the same manner as in Production Example 1 except that the composition of the pre-emulsion to be dropped was as shown in Table 1. The solid content and pH of each emulsion are also shown in Table 1.

[0030]

[Table 1]

Example 1 Preparation of water-based matting paint Example 1 The following composition was blended in a stainless steel container having a capacity of 0.5 liter and stirred with a stirrer for 20 to 40 minutes to prepare a pigment paste.

Tap water 50 parts “Nopco Sperse 44C” (manufactured by San Nopco, a pigment dispersant) 2.1 parts “SN Deformer-364” (manufactured by San Nopco, an antifoaming agent) 5 parts 2.5% Hydroxyethyl cellulose (thickener) 40 parts Titanium white (specific gravity: 3.9) 111 parts Diatomaceous earth (specific gravity: 2.3) 33 parts Based on 241.1 parts of the obtained pigment paste, Production Example 1 described above. Emulsion A having a solid content of 50.2% obtained in
Parts, adipic dihydrazide 2 parts, and isobutyric acid (2,
10 parts of 2,4-trimethyl-3-hydroxypentyl) ester were mixed and stirred for 10 to 20 minutes to obtain a paint.

Examples 2 and 3 and Comparative Examples 1 to 5 Example 1 was repeated except that the composition and amount of the pigment paste and the type of emulsion were as shown in Table 2.
Each coating was obtained in the same manner as described above. Table 2 also shows the elongation percentage and the like of the coating film by each paint. The specific gravities of the clay and tanker in the table are 2.6 and 2.7, respectively.

(Note 1) Elongation (%), breaking strength (kg / cm ² ), shrinkage stress (kg / cm ² ) of the formed coating film: JI
A test piece was prepared according to SA 6909, and the elongation percentage, breaking strength, and shrinkage stress of the dried coating film were measured using a tensile tester Autograph AG2000B (manufactured by Shimadzu Corporation). The elongation and breaking strength are 200 ° C and the tensile speed is 200.
Under the condition of mm / min, the shrinkage stress is from 20 ° C to -20 ° C.
And then measured.

[0035]

[Table 2]

Preparation of paint for elastic base The compositions shown in Table 3 were blended with the emulsion obtained in the above production example, and the mixture was stirred and mixed to obtain each paint for elastic base. Table 3 also shows the elongation percentage of the coating film by each paint.

[0037]

[Table 3]

Coating Examples 4 to 8 and Comparative Examples 6 to 12 Each of the elastic base paints obtained above was adjusted to an appropriate coating viscosity with water, and then sandblasted on a mortar plate (90 × 300 × 20 mm). The film was coated with a roller so that the coating amount was about 1.0 kg / m ^2, and dried at 20 ° C. and 75 RH% for one day. Next, various water-based matting paints were applied on each base coating film in a combination shown in Table 4 by an airless spray at an application amount of about 0.2 kg /
m ^2, and dried at 20 ° C. and 75 RH% for 7 days to obtain a painted plate. Table 4 shows the performance test results of these coated plates.

Test Method (Note 2) Finished appearance: The finished appearance of the coating film surface of each coated plate was visually evaluated. A sample that was uniformly and smoothly finished without any irregularities in the appearance of the coating film was rated as “A”, and a sample that had unevenness, poor concealing properties, or a matte finish was rated as “x”.

(Note 3) Resistance to repeated action of heating and cooling:
According to JIS A 6909, the coated plate is immersed in water at 20 ° C. for 18 hours, and then immediately immersed in a -20 ° C. constant temperature bath.
The coated surface was visually observed after repeating the operation of cooling for 24 hours and then heating in a constant temperature bath at 50 ° C. for 3 hours. This operation was repeated 10 times with 24 hours as one cycle, 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 4) Adhesion: The adhesion of the coating film surface of each coated plate was evaluated by touch with the following criteria.

：: No tackiness was observed at all, or slight tackiness was observed, but there was no practical problem.

X: Adhesion was recognized considerably, and there was a problem in practical use.

[0046]

According to the present invention, a water-based matting paint which can form a matte coating film having sufficient hiding properties and excellent durability even at a low pigment concentration can be obtained. Multi-layer paint finish with appearance and high durability is possible. It is particularly useful for painting the inner and outer walls of buildings.

[0047]

[Table 4]

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09D 7/12 C09D 7/12 Z

Claims (3)

[Claims] 1. An emulsion (A) of a carbonyl group-containing copolymer having a Tg of -30 to 15 ° C. and a polyhydrazide compound (B) having at least two hydrazide groups in one molecule are mixed with the emulsion particles. Carbonyl group 1
The amount of the hydrazide group is 0.02 to 3.0 equivalents relative to the equivalent, and the pigment dispersion (C) containing a matting agent is added to the resin dispersion containing 25 to 40% by volume of the pigment.
A water-based matting paint characterized in that it is contained so that 2. An undercoat is applied to a surface to be coated, and an emulsion (A) of a carbonyl group-containing copolymer having a Tg of -30 to 15 ° C., and a polymer having at least two hydrazide groups in one molecule. The resin dispersion containing the hydrazide compound (B) in such an amount that the amount of the hydrazide group is 0.02 to 3.0 equivalents to 1 equivalent of the carbonyl group in the emulsion particles is added to the pigment component containing the matting agent ( A paint finishing method comprising applying a water-based matting paint containing C) so as to have a pigment volume concentration of 25 to 40% in the paint as a top coat. 3. A coating containing a carbonyl group-containing copolymer emulsion (D) and a pigment (E) as an undercoat, wherein the pigment has a volume concentration of 30 to 70% and an elongation of the formed coating film of 20. Elastic base that is 30% or more
3. The method according to claim 2, wherein a coating material is applied.