JPH0684484B2 - Paint composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coating composition having remarkably improved pigment dispersibility,
In particular, it relates to a mixed color coating composition.

[Prior Art] Conventionally, paints using an acrylic resin are excellent in various coating film performances, and are therefore widely used as paints for various building materials including mortar paints.

However, acrylic paints generally have poor pigment dispersibility, and various proposals have been made to improve the dispersibility. For example, JP-A-56-127671 attempts to improve pigment dispersibility by using a copolymer in which a phosphoric acid ester monomer represented by a specific formula and a dialkylaminoalkyl (meth) acrylate are used in combination. It is a thing.

[Problems to be Solved by the Invention] However, such a proposal merely proposes a method of improving good dispersibility only in a single pigment, for example, a white monochromatic system, a blue monochromatic system, and a black monochromatic system. That is, the inventors of the present invention further studied after that, even if the above resin is used as a mixed color paint by mixing a single color paint such as white paint, blue paint, black paint, so-called paint The dispersibility of the pigment decreases during storage and color separation occurs, and the desired coating film cannot be obtained, or the obtained dry coating film shows a mottled and inferior glossy surface due to reaggregation of pigment particles. It turns out that there are problems that result. That is, in the case of a monochromatic pigment, the resin to be used is preferably used as a paint if it has excellent pigment dispersibility, but it is not always sufficient in a mixed color paint, and the miscibility of the pigments, that is, It is an indispensable condition that two or more different pigments are uniformly dispersed at the same time, and it is necessary for the resin to be able to maintain the state for a long period of time. The current demand is that various subtly different colors are used in many cases, and in this sense, a resin having excellent dispersibility is required for mixed color paints.

[Means for Solving the Problems] However, as a result of further studies to improve the above-mentioned drawbacks, the present inventors have found that (However, in the formula, R ₁ is a hydrogen atom or a methyl group, and R ₂ is a carbon atom 1
~ 5 alkylene group, R ₃ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a hydroxy-substituted alkyl group. ) 0.01 to 0.5% by weight of a phosphoric acid ester-based monomer represented by the formula (b), (b) 5 to 30% by weight of a hydroxyl group-containing (meth) acrylic acid ester-based monomer (c) a (meth) acryl having an alkyl group having 5 to 18 carbon atoms. Acid ester monomer 5-40% by weight (d) Other monomer 89.99-29.5% by weight It was found that a coating material composed of a copolymer and two or more kinds of pigments meets the purpose, and the present invention is completed. Arrived

Although the object of the present invention is to try to improve the pigment miscibility with respect to the mixed color paint system as described above, it goes without saying that good pigment dispersibility can be obtained even with a single pigment.

Each of the components (a) to (c) of the copolymer used in the present invention is a monomer described in JP-A-56-127671, but in the present invention, a specific type of monomer is selected from these. The initial purpose can be achieved only by using a specific amount and by combining these, and the effect obtained and the resin composition cannot be inferred from the known literature.

Hereinafter, each of the components (a) to (d) of the copolymer will be described.

Examples of the phosphoric acid ester-based monomer used as the component (a) include acid phosphoroxyalkyl (meth) acrylic acid esters or their alkylene oxide adducts, dialkyl phosphate alkyl (meth) acrylic acid esters or dialkyl phosphite alkyl (meth). Acrylic ester, etc.
It is 0.01 to 0.5% by weight. Outside this range, that is, when less than 0.01% by weight, the effect of use is not observed, especially the pigment dispersibility is deteriorated, and when it exceeds 0.5% by weight (b), which will be described later.
Since the balance with (c) becomes unbalanced, even if the dispersibility of the pigment is maintained to some extent, the deterioration of the viscosity stability of the above-mentioned color-mixed coating material with time is recognized, which is unsuitable as a coating material. The particularly preferred amount of component (a) used is 0.05 to 0.3% by weight.

Examples of the hydroxyl group-containing (meth) acrylic acid ester-based monomer used as the component (b) include 2-hydroxyethyl (meth) acrylic acid ester, 2-hydroxypropyl (meth) acrylic acid ester, and 2-hydroxy1-methylethyl ( (Meth) acrylic acid ester, 4-hydroxybutyl (meth) acrylic acid ester, 3-hydroxypropyl (meth) acrylic acid ester, 3-hydroxybutyl (meth) acrylic acid ester, 3-chloro-2-
Examples thereof include hydroxypropyl (meth) acrylic acid ester, and 2-hydroxyethyl (meth) acrylic acid ester is particularly preferable. The amount of the component used is 5 to 30% by weight. If it is less than 5% by weight, the effect of the combined use with the components (a) and (c) is not recognized, and if it exceeds 30% by weight, the water resistance is reversed. It is not preferable because the deterioration of performance is observed.
The particularly preferred amount of component (b) used is 10 to 20% by weight.

Examples of the (meth) acrylic acid ester-based monomer having an alkyl group having 5 to 18 carbon atoms used as the component (c) include n-amyl (meth) acrylic acid ester, n-hexyl (meth) acrylic acid ester, and n-heptyl. (Meta)
Acrylic acid ester, n-octyl (meth) acrylic acid ester, 2-ethylhexyl (meth) acrylic acid ester, dodecyl (meth) acrylic acid ester, octadecyl (meth) acrylic acid ester and the like can be mentioned, but especially 2-ethylhexyl ( (Meth) acrylic acid ester is preferred. The amount of the component used is 5 to 40% by weight, and if it is outside this range, for example, less than 5% by weight, water resistance, particularly warm water resistance, and if it exceeds 40% by weight, deterioration of performance such as stain resistance is recognized. . The particularly preferred range of the component (c) is 10 to
30% by weight.

Most preferably, the other monomer used as the component (d) is a (meth) alkyl group having 1 to 4 carbon atoms.
Acrylic esters, especially methyl (meth) acrylate,
Ethyl (meth) acrylate, styrene, and vinyltoluene. These are mainly vinyl acetate, vinyl propionate, vinyl ester monomers such as vinyl versatate, (meth) acrylonitrile, (meth) acrylamide, (anhydrous) maleic acid, mono (or di) alkyl maleate, and fumaric acid mono ( Or di) alkyl,
(Anhydrous) itaconic acid, mono (or di) alkyl itaconic acid, (anhydrous) citraconic acid, acrylic acid, methacrylic acid, crotonic acid and other carboxyl group-containing monomers, dimethylaminoethyl (meth) acrylic acid ester, diethylaminoethyl (meth ) Acrylic acid ester, butylamino (meth) acrylic acid ester, 2-vinylpyridine, 4-vinylpyridine, 2-methyl-5-vinylpyridine, N-vinylimidazole, 2-methyl-N-vinylimidazole, dimethylallylamine, Monomers having a basic group such as diallylamine, vinylpyrroline, vinylquinoline and N, N-dimethylaminoethyl vinyl ether can also be used. The amount of the component used is 89.99 to 29.5% by weight, and if it exceeds 89.99% by weight, as a result (a) to
The balance of (c) is upset, and the object of the present invention can be achieved. Also, when the content is less than 29.5% by weight, various performances, especially even basic performance as a paint, cannot be satisfied. Become. The particularly preferred range of the component (d) is
50 to 85% by weight, and the most preferable combination among them is styrene / methyl methacrylate, styrene / ethyl methacrylate in the component (d) of 90% by weight or more, and a copolymerization ratio of 30/70 to 70/30 ( Weight ratio).

The copolymer of the present invention can be produced by ordinary solution polymerization. As the solvent to be used, aromatic solvents such as toluene, xylene and benzene, ester solvents such as methyl acetate, ethyl acetate and butyl acetate, alcohol solvents such as isopropyl alcohol and n-butyl alcohol, and ketone solvents such as methyl ethyl ketone are optional. Can be used for As the polymerization initiator, azobisisobutyronitrile, benzoyl peroxide, t-butyl perbenzoate, di-t-butyl peroxide, t-butyl hydroperoxide,
Cumene hydroperoxide or the like is used.

Various pigments are used in the coating material of the present invention. Such pigments include titanium oxide, calcium carbonate, talc, lithopone, red iron oxide, alumina, clay, barium sulfate, calcium sulfate, chromium oxide, phthalocyanine blue, phthalocyanine green, lake red, lake yellow, yellow lead, chrome vermilion, navy blue, Ultramarine blue, oak yellow, hansa yellow, various carbon blacks, etc. are mixed in an arbitrary ratio.

The combination of monochromatic paints in which the effects of the present invention are particularly remarkable are white paint and black paint, white paint and blue paint, white paint and yellow paint, and yellow paint and blue paint.

The coating material of the present invention is prepared by blending a pigment in the organic solvent solution of the above copolymer, and optionally blending additives such as a plasticizer, an anti-sagging agent, an anti-settling agent and an antifoaming agent. . As the organic solvent, for example, toluene, xylene,
Aromatic hydrocarbons such as benzene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, ester systems such as ethyl acetate, butyl acetate and cellosolve acetate, and alcohol systems such as isopropyl alcohol, n-butanol, isobutanol and butyl cellosolve are used. It

The paint of the present invention is suitable as a top coat paint for concrete, mortar buildings, floors, roof tiles, etc., and can be used as a paint for any other substrate.

As the coating method, iron coating, brush coating, roller coating,
A method such as spraying is adopted. The coating amount is not particularly limited, but is often 10 to ²⁰⁰ g / m ^{2 in} terms of solid content deposition amount. After coating, known means such as room temperature drying, baking drying, and heat drying are used.

[Examples] Hereinafter, the coating material of the present invention will be described in more detail with reference to Examples. In the examples, "part" or "%" is based on weight unless otherwise specified.

Production Example of Copolymer 0.1 part of acid phosphooxyethyl methacrylate as component (a), 15 parts of 2-hydroxyethyl methacrylate as component (b), 22 parts of 2-ethylhexyl acrylate as component (c), component (d) As a raw material, 20 parts of styrene and 42.9 parts of methyl methacrylate were charged, and 1.2 parts of t-butyl perbenzoate was added to this to obtain toluene / butyl acetate = 8.
The mixture was added dropwise to 0 part / 20 parts of the mixed solution in 4 hours, and further maintained at the same temperature for 7 hours. The obtained copolymer is referred to as "resin-1".

Hereinafter, Resins 2 to 10 were produced according to the above.

Resin-2 Acid phosphooxyethyl methacrylate / 2-hydroxyethyl methacrylate / n-hexyl acrylate /
Styrene / methyl methacrylate = 0.1 / 17 / 22.9 / 30/30
(Weight ratio, the same applies hereinafter) Resin-3 Acid phosphooxyethyl acrylate / 2-hydroxyethyl acrylate / 2-ethylhexyl acrylate / styrene / methyl methacrylate / ethyl methacrylate = 0.1 / 15/22/20/20 / 22.9 Resin-4 acid phosphooxyethyl methacrylate / 2-hydroxyethyl acrylate / n-hexyl acrylate / styrene / methyl methacrylate = 0.1 / 15 / 24.9 / 25/35 Resin-5 acid phosphooxyethyl methacrylate / acrylic acid 2- Hydroxyethyl / n-hexyl acrylate / styrene / methyl methacrylate / ethyl methacrylate = 0.
2/15/25/20/30 / 19.8 Resin-6 (control example) 2-hydroxyethyl acrylate / 2-ethylhexyl acrylate / styrene / methyl methacrylate = 15/22 /
20/43 Resin 7 (control example) Acid phosphooxyethyl methacrylate / 2-ethylhexyl acrylate / styrene / methyl methacrylate = 0.1 / 25/30 / 44.9 Resin-8 (control example) Acid phosphooxyethyl methacrylate / acrylic acid 2 -Hydroxyethyl / styrene / methyl methacrylate = 0.2 / 20/40 / 37.8 Resin-9 (control example) Acid phosphooxyethyl methacrylate / 2-hydroxyethyl methacrylate / 2-ethylhexyl acrylate / styrene / methyl methacrylate = 1 / 15/22/20/42 Resin-10 (control example) Acid phosphooxyethyl methacrylate / 2-hydroxyethyl acrylate / 2-ethylhexyl acrylate / styrene / methyl methacrylate = 1/50/10/20/18 Implementation Example Copolymer "Resin 1-10" 100 parts by weight of various pigments and thinner (xylene) After 20 parts and 250 parts of glass beads were added and kneaded in a sand mill for 1 to 3 hours, the glass beads were passed to obtain white enamel, black enamel and blue enamel.

Mix the obtained enamel in equal amounts with a disper,
White / black, white / blue mixed enamel was prepared.

Put this mixed enamel in a container and seal it at 20 ℃, 60
After leaving it at a temperature of ℃ for 18 days and 30 days, it was taken out and spray-coated on a tin plate to a thickness of about 50μ. Thirty seconds after the spray application, ethyl acetate was added dropwise and a rubbing test was performed to observe the color-separated state. After spray coating, the color difference (ΔE) was measured after drying at room temperature for 1 day.

The results are shown below.

The enamel of each color mixture of "Resin-6" and "Resin-8" was obviously inferior in pigment dispersibility as compared with other enamel, and the tendency of reaggregation of the pigment was observed in the paint after being left for 18 days. .

Further, each enamel using "Resin-9" and "Resin-10" had a thickening with time and was not suitable for practical use.

[Effect] As described above, since the coating composition of the present invention has very good miscibility with a mixed pigment system in particular, it does not cause color separation or mottled pattern on the coating film even after a long time after coating, and thus it is aesthetically pleasing. It is possible to obtain an excellent coating film. Further, it is of course also excellent in other properties such as weather resistance and water resistance, and can be a very useful coating material in industry.

Claims (1)

[Claims] 1. (However, in the formula, R ₁ is a hydrogen atom or a methyl group, and R ₂ is a carbon atom 1
~ 5 alkylene group, R ₃ represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a hydroxy-substituted alkyl group. ) 0.01 to 0.5% by weight of a phosphoric acid ester-based monomer represented by the formula (b), (b) 5 to 30% by weight of a hydroxyl group-containing (meth) acrylic acid ester-based monomer (c) a (meth) acryl having an alkyl group having 5 to 18 carbon atoms. Acid ester monomer 5 to 40% by weight (d) A coating composition comprising a copolymer of 89.99 to 29.5% by weight of other monomer and two or more kinds of pigments.