JPS6036576A - Composition for water-dispersed paint - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of an emulsion obtained by the emulsion polymerization of a mixture of methylstyrene and a copolymerizable monomer, giving a coating film resistant to whitening and having excellent water-resistance, and useful for the coating of wood, metal, etc. CONSTITUTION:The objective composition is produced by using a copolymer emulsion obtained by the emulsion polymerization of a monomer mixture composed of (A) 10-90(wt)% p-methylstyrene, o-methylstyrene and/or m-methylstyrene of formula and (B) 90-10% copolymerizable monomer [e.g. methyl (meth) acrylate].

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-dispersible coating composition with excellent water resistance. More specifically, in the fields of metal coating, inorganic coating, wood coating, etc., the composition for water-dispersed coatings has excellent water resistance and does not cause abnormalities such as whitening of the coating film due to water on the coating. It is something that provides something.

Conventionally, in the fields of metal coatings, inorganic coatings, water conservancy coatings, etc., solvent-based coatings are commonly used. However, since solvent-based paints contain organic solvents, they pose problems such as the risk of ignition, hygiene, and pollution.Therefore, there has been a desire to develop a coating technology using water-dispersed paints.

Conventionally, when water-dispersed paints were used for metal painting, inorganic material painting, wood painting, etc., when these painted objects were immersed in water, the paint film became white due to the water, which is a significant problem in practical use. There were some flaws that detracted from its beauty.

As a result of intensive research to solve the above-mentioned problems, the present inventor has developed a composition for water-dispersible paints with water control 141- by emulsion polymerizing methylstyrene and a monomer capable of copolymerizing with it. The present invention was completed after discovering that it could be made into a product.

That is, the present invention provides p-methylstyrene, O-methylstyrene, m-methylstyrene (7) 1 type 1 talri, which is expressed by the general formula
A copolymer emulsion with excellent water distribution properties obtained by emulsion polymerization of a monomer mixture consisting of 10 to 90% by weight of a mixture of two or more types and 90 to 102j'fi% of a copolymerizable monomer. This is a composition for water-dispersed paint.

Examples of monomers copolymerizable with one or more mixtures of p-methylstyrene, 0-methylstyrene, and m-methylstyrene used in the present invention include methyl (meth)acrylate and ethyl (meth)acrylate. , butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, stearyl (meth)acrylate Kasa's (meth)acrylic acid alkyl ester, and glycidyl (meth)acrylate
(meth)acrylic acid glycidyl esters such as acrylate), and (meth)acrylic acid hydroxy esters such as 2-hydroxyethyl (meth)acrylate.
meth)acrylic acid esters, styrenes such as α-methylstyrene and styrene, unsaturated basic acids such as (meth)acrylic acid and crotonic acid, and their salts;
Unsaturated dibasic acids such as itaconic acid, fumaric acid, maleic acid and their half esters and salts, amides of unsaturated carbonic acids such as (meth)acrylamide and N-methylol (meth)acrylamide, divinylbenzene, Polyvalent vinyl compounds such as ethylene glycol di(meth)acrylate L/-1, tetraethylene glycol di(meth)acrylate, trinotylpropane I and methacrylate-1, and acrylonitrino There are acid-resistant vinyl, N-vinylpyrrolidone, and butadiene.

Note that the above (meth)acrylic means methacrylic or acrylic.

p- in the monomer mixture forming the copolymer emulsion.
If the concentration of one or more of methylstyrene, 0-methylstyrene, and m-methylstyrene is less than 10M, water resistance will be poor, while if it is more than 90%, fusion of emulsion particles will be prevented. , it is not practical because it does not form a uniform coating film and cracks occur, and therefore it is rated at 10-9.
0 weight section, the following are required, and 50 to 70 fi
It is preferable that the amount is within the range of

A copolymer emul/con is obtained from the monomer mixture by a known emulsion polymerization method. For example, as a surfactant, an anionic surfactant such as alkyl sodium sulfate or fatty acid soda, or polyoxyethylene alkyl ether,
Examples include nonionic surfactants such as polyquine ethylene alkyl phenyl ether, or a combination of both.
Examples of the polymerization initiator include peroxides such as potassium persulfate and cumenohydroboroxide, azo compounds such as azobisinobutyronitrile, and redox compounds.

However, there is no problem in using chain transfer agents such as dodecyl mercaptan, carbon tetrachloride, and inoflovir alcohol during emulsion polymerization.

In general, there is a method in which a surfactant, water, a polymerization initiator, and a monomer mixture are charged together in a reactor and the heated jQ polymerization reaction is carried out, and a method in which a monomer mixture is added later as the polymerization reaction progresses. Alternatively, a copolymer emulsion can be obtained by a method such as a polymerization method in which a surfactant, water, a polymerization initiator, a monomer mixture, etc. are added to the seed latex, and a polymerization reaction is carried out in which new particles are not generated. The copolymer emulsion thus obtained has a resin/water ratio of 30/70 to 60.
/40 is common.

The water-dispersed coating composition of the present invention can be prepared from the above-mentioned copolymer emulsion; Tsukasa9yj agent, /l″i (foaming agent, preservative,
There is no problem even if a mold release agent or the like is added.

7) How to apply the coating composition of the present invention:
Regular brushing, spraying, troweling, roll coater
, a flow coater, a knife coater, etc. 3.Although drying is usually carried out at room temperature, it is also possible to carry out heating drying using far infrared rays or the like.

The water-dispersed coating composition of the present invention is particularly suitable for coating metals such as cast metals, cement tiles, inorganic materials such as slate I and boards, plywood, veneer boards, etc., and is a coating with excellent water resistance. Forms a film.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. "Parts" shown in the following examples indicate parts by weight unless otherwise specified.

Examples 1 to 5 and Comparative Examples 1 to 3 Production of copolymer emulsions: Using a monomer mixture, a polymerization initiator, and a chain transfer agent in the proportions shown in Table 1, these were mixed with 150 parts of deionized water and sodium dodecyl sulfate. A copolymer emulsion was obtained by reacting in one part at 70°C for 8 hours.

Preparation of water-dispersed paint: 100 parts by weight of the above copolymer emulsion, 10 parts of butylcelonolb as a film-forming agent, and carbon black toner (manufactured by Inu Nisseika (silk), trade name: EP-510').
Black TR) 5 parts by weight were mixed, and the mixture was stirred and mixed in a disper to form a paint.

Paint test: Table 2 shows the test results of paint films created using these paints.

Painting is done with air spray, and the object to be painted is 0.8111
The polished mild steel plate was dried at 20°C for one week.

Table 1 Arrow 1 Shows the weight percent of the total amount of p-methylstyrene, 〇-methylstyrene, and m-methylstyrene in the monomer mixture.

≠2 Visual judgment.

The painted object was immersed in tap water at -325°C, taken out and the dried paint film was visually judged.

Claims (1)

[Claims] (1) 10 to 90% by weight of one type or a mixture of two or more of p-methylstyrene, o-methylstyrene, Iη-methylstyrene, which is represented by the general formula, and a monomer copolymerizable therewith. body 9
A water-dispersed coating composition having excellent water resistance and comprising a copolymer emulsion obtained by emulsion polymerization of a monomer mixture consisting of 0 to 10% by weight.