JPS62169868A - Elastic paint composition - Google Patents

Abstract

PURPOSE:To improve blend stability during the production of paint and to improve the flexibility of a coating film at a low temp., by using an acrylate latex obtd. by copolymerizing a specified monomer as a constituent ingredient of a polymer as a binder for elastic paint. CONSTITUTION:An elastic paint compsn. is formed by using the following polymer latex as a binder and an inorg. filler. As the polymer constituent components of the latex, 97-60wt% ethylenically unsaturated carboxylic acid ester mononmer (1) other than the following component (3), 0.5-10wt% ethylenically unsaturated acid monomer (2), 0.1-10wt% monomer (3) of the formula (wherein R1 and R2 are each H or methyl; R3 is H, methyl or CH2= CR1-CO- group; n is an integer of 1-25) and 0-20wt% monomer (4) copolymerizable with the above monomers are used. As the monomer (1), alkyl acrylates are particularly preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an elastic coating composition that has excellent formulation stability, which is suitable for coating production, and has excellent coating film flexibility at low temperatures.

(Prior Art) Examples of binders conventionally used in the elastic paint include:
Special Publication No. 49-16352, Special Publication No. 60-3842
As seen in Publication No. 4, etc., an acrylic latex mainly composed of (meth)acrylic acid ester monomers has been used.

(Problems to be Solved by the Invention) However, in the polymer latex, when inorganic fillers such as calcium carbonate, titanium oxide, and talc are added and mixed at high speed during paint production, coagulation tends to occur. That is, they have the disadvantages of poor blending stability, the tendency for cracks to occur in the coating film when it dries, and furthermore, the flexibility of the coating film is extremely poor, especially at low temperatures.

As a result of intensive research in order to solve the above-mentioned drawbacks, the present inventors have discovered that by using acrylate latex, which is copolymerized with a specific monomer as a polymer constituent, as a binder for elastic paints, p. The present invention was completed based on the discovery that the above objects were achieved.

(Means for Solving the Problems) An object of the present invention is to provide an elastic coating composition comprising an inorganic brightening agent and a polymer latex as a binder. In the polymer as a binder, (1) 97 to 60% by weight of an ethylenically unsaturated carboxylic acid ester monomer other than the following (3) (2) 0.5 to 10% by weight of an ethylenically unsaturated acid monomer 0.1-
(4) Achieved by using an elastic coating composition characterized by using a polymer latex consisting of 0 to 20% by weight of a monomer copolymerizable with each of the above monomers. be done.

The elastic coating composition of the present invention is used in coating applications that require a coating film to have conformability to cracks on the surface of structures such as concrete, mortar, and flexible boards, waterproof properties, and cosmetic properties.

The contents will be explained below.

The monomer (3) represented by the above general formula is polyethylene glycol mono(meth)acrylate.

Polyprolene glycol di(meth)acrylate.

polypropylene glycol mono(meth)acrylate,
Examples include methoxypolyethylene glycol mono(meth)acrylate, which can be used alone or in a mixture of two or more. The content of this monomer in the polymer is 0.
It's 5-10ffi'Achi.

If it is less than 0.1% by weight, it is undesirable because the formulation stability during paint production and the flexibility of the coating film at low temperatures will be extremely reduced, and if it exceeds 10% by weight, the above performance will hardly change and it is not economical. Kototo.

This is not preferable because water resistance decreases. Preferably 0, 5
-8% by weight, more preferably 0.5-6% by weight.

Ethylenically unsaturated cargenic acid ester monomers other than monomer (3) include acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, octyl acrylate, and 2-ethylhexyl acrylate, methyl methacrylate, f Methacrylic acid alkyl esters such as robyl methacrylate and dithyl methacrylate, unsaturated radicals such as dimethyl maleate, diethyl maleate, dibutyl maleate, dimethyl fumarate, and butyl fumarate? Examples include dialkyl esters of phosphoric acid, and one or more of these may be used.

Particularly preferred are acrylic acid alkyl esters.

The content of the monomer in the polymer is 97 to 60, and
If the weight is less than 60%, the flexibility will decrease. Preferably 95
~70% by weight, more preferably 95-80% by weight.

Examples of ethylenically unsaturated acid monomers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, etc.; unsaturated radicals such as itaconic acid monoethyl ester and maleic acid mottyl ester; monoalkyl esters of phosphoric acid; examples include unsaturated cargenic acids such as sulfonityl acrylate Na salt, sulfoglopyru methacrylate Na salt, acrylamide-propanesulfonic acid, unsaturated sulfonic acids, and salts thereof; one or two of these; More than one species is used. The content of the ethylenically unsaturated acid monomer in the polymer should be 0.5 to 10% by weight, and if it is less than 0.5% by weight, the formulation stability during paint preparation will be poor, and if it exceeds 10% by weight. and the flexibility of the paint film decreases. Preferably 0.5 to 8% by weight,
More preferably, it is 0.5 to 6% by weight.

In the present invention, a polymerizable monomer may be included in the polymer to increase the toughness, flexibility, etc. of the coating film. Such monomers include conjugated dienes such as 1,3-butadiene, isoprene, 1#3-hentadiene, and chloroprene; aromatic vinyl monomers such as styrene and α-methylstyrene; acrylonitrile, methacrylonitrile, etc. unsaturated nitrile monomers; N-alkylolamides of ethylenically unsaturated acids such as N-methylolacrylamide; glycidyl group-containing monomers such as glycidyl acrylate; hydroxyl group-containing monomers such as allyl alcohol and 2-hydroxyethyl acrylate; Examples include amine group-containing monomers such as NsN'-dimethylaminoethyl acrylate; and amide group-containing monomers such as maleamide. One or more of these may be used, but the content of t in the polymer is 20
s or less.

In the present invention, the method for producing the polymer lacax of the present invention is not particularly limited, and it is produced by a known emulsion polymerization method. Usually, as a polymerization initiator, an organic peroxide, a redox catalyst system, a persulfate such as potassium persulfate, ammonium persulfate, etc. are used. As the emulsifier, anionic surfactants, nonionic surfactants, etc. may be used alone or in combination of two or more. The polymerization temperature is 0 to 100°C, and the polymerization methods include continuous polymerization and patch polymerization.

The amount of the polymer latex used in the elastic coating composition of the present invention is usually 25 to 250 parts by weight in terms of solid content per 100 parts by weight of the inorganic filler.

If it is less than 25 parts by weight, the coating film is likely to crack.

If it exceeds 250 parts by weight, the strength of the coating film will decrease.

It becomes difficult to prevent the paint film from blistering after immersion in water.

Preferably it is 30 to 200 parts by weight.

The inorganic fillers used in the present invention include calcium carbonate,
Examples include barium sulfate, barium carbonate, clay, Merck, alumina, aluminum hydroxide, titanium oxide, asbestos, mica, etc., but are not limited to these as long as they are commonly used for elastic paints.

In the composition of the invention, tripolyphosphoric acid.

One or more dispersants such as sodium salts or ammonium salts such as hexametaphosphoric acid, nonionic surfactants, and anionic surfactants, methylcellulose, cal?
oxymethylcellulose? One or more thickeners such as lipinyl alcohol and polyacrylic acid salts, desiccant agents, antiseptics, antifungal agents, antifreeze agents, and the like can be used as necessary.

The present invention will be specifically explained below using Examples.

In addition, the test method in the examples is as follows.

(1) Compound stability test Using a mechanical stability tester (Marlon stability tester), under the following conditions, the generated coagulum (the amount that did not pass through the fish mesh wire mesh) was expressed as a percentage by weight relative to the solid content of the paint. This was an evaluation of formulation stability. The smaller the number, the better the formulation stability.

Solid concentration: 25 tirrotor rotation speed: 1100 orp Load: 10 kg/crn” Rotation time
10 minutes (2) Crack resistance test by initial drying JIS A
5403, a flexible board with a thickness of 4 m is coated with the specified paint at a rate of 1.5 kp/-, and a wind speed of 3 m/- is applied.
After 6 hours, the test plate was taken out and visually observed to see if any cracks had occurred on the surface.

(3) Low-temperature elongation test A test piece with a distance between gauge lines of 20 m1 and a chuck distance of 60 ta
The test piece was installed in a tensile testing machine so that the temperature in the tank was -10°C, and after leaving it for 4 hours, a force was applied at a tensile speed of about 200 m/min until the test piece broke. The elongation for a distance between chucks of 60 m at the time of breakage is determined. The preparation of the sample is
A glass plate with a 2M thick frame attached to the periphery is leveled,
The composition was poured into this, the surface was made uniform with a percoater, and the composition was dried in a constant temperature room in the following order: 20°C x 1 day → 30°C x 1 day → 20°C x 14 days.

Example 1 The composition shown in Table 1 (wt%) was obtained by ordinary emulsion polymerization.
A polymer latex having the following properties was prepared.

The fillers and other compounds shown in Table 2 were gradually added to these four types of polymer latex while stirring with a TK Homodisno (stirrer manufactured by Tokushu Kika Kogyo Co., Ltd.) (dry pigment method), and the viscosity was determined. is approximately 2,000 cps (room temperature,
Bfi viscosity needle, 60 rpm) and a pH of 8 to 9 were prepared.

Table 3 shows the evaluation results of the formulation stability and cracking property during initial drying of these paints, and the elongation of the paint film at low temperatures.

Table 2 Filler (1) st, a Dispersant (sodium tritetraphosphate) 0.2 Thickener (2)
0.2 Antifoaming agent (3) 0.
1 Note) (1) Sankyo Seifun Co., Ltd. product special grade calcium carbonate (2) Shin-Etsu Chemical Co. I Metrose 908H15,
000 (3) Asahi Denka I Adekane) B18
7 Example 2 Polymer latexes having the nine compositions (weight 1) shown in Table 4 were prepared in the same manner as in Example 1.

Table 4 In the same manner as in Example 1, each paint was prepared, and after that, each coating material and coating film were evaluated, and the results are shown in Table 5.

From the above results, it can be seen that even if the type of monomer is changed, each performance is very excellent in this example with respect to the composition of the pace.

Claims (1)

[Scope of Claims] In an elastic coating composition comprising an inorganic filler and a polymer latex as a binder, the binder contains (1) an ethylenically unsaturated carboxylic acid ester monomer other than the following (3) in the polymer; (2) Ethylenically unsaturated acid monomer 0.5-10% by weight, (3) General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 and R_2 are hydrogen or methyl The group is R_
3 represents hydrogen, a methyl group, or a ▲ group that has a mathematical formula, chemical formula, table, etc., and n represents an integer from 1 to 25.)
An elastic paint characterized by using a polymer latex consisting of 0.1 to 10% by weight of a monomer represented by (4) 0 to 20% by weight of a monomer copolymerizable with each of the above monomers. Composition.