JPH06299093A - Preparation of aqueous rust-proofing coating dispersion - Google Patents

Abstract

PURPOSE:To provide a coating dispersion problem-free in respect of storage stability, safety and hygiene, and excellent in coating film properties such as rust-proofing properties, water resistance and adhesion. CONSTITUTION:A condensation reaction of (II) at least one silicon-contg. compd. selected from among alkoxysilanes and cyclosiloxanes is allowed to proceed in the presence of (I) 100 pts.wt. (as solid) aq. dispersion obtd. by emulsion polymn. of a monomer component comprising (a) 40-99.5wt.% alkyl (meth) acrylate and/or arom. vinyl monomer, (b) 0.5-50wt.% ethylenically unsatd. carboxylic acid, and (c) other ethylenically unsatd. monomer copolymerizable with the components (a) and (b).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rust preventive paint having excellent rust preventive properties, water resistance, adhesion and storage stability, which can be used for metal paints such as pre-coated metal, aluminum sash, can and metal parts. The present invention relates to a method for producing a water dispersion.

[0002]

2. Description of the Related Art Conventional solvent-based or organic solvent-containing water-based paints have been used for rust prevention of metals, but from the viewpoint of solvent pollution, safety and hygiene, resource saving, etc. Alternatively, it is desired to shift to an aqueous system that uses a solvent as little as possible, and various methods for making an aqueous system have been proposed. For example, in JP-A-3-131370, a surface treatment method and surface of a galvanized steel material using an ethylenically unsaturated carboxylic acid copolymer dispersion to which a water-dispersible silica, a water-dispersible chromium compound and an alkoxysilane compound are added. Treatment compositions have been proposed. However, in the conventional technology, the acrylic copolymer alone is still insufficient in anticorrosion properties, and heavy metals such as chromium compounds added to improve anticorrosion properties are problematic in terms of environment and hygiene. There is. Furthermore, the addition of water-dispersible silica, alkoxysilane compounds, phosphoric acid, etc., has poor compatibility, and there is a problem in storage stability.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and is excellent in rust prevention, water resistance, adhesion, and storage stability without any problems in environmental hygiene. It is an object of the present invention to provide a method for producing an aqueous dispersion for rust preventive paint.

[0004]

The present invention provides (I) (a)
Alkyl (meth) acrylate and / or aromatic vinyl monomer 40 to 99.5% by weight, (b) ethylenically unsaturated carboxylic acid 0.5 to 50% by weight, and (c)
0 to 59.5% by weight of other ethylenically unsaturated monomer copolymerizable with the components (a) and (b) [provided that (a) +
(B) + (c) = 100% by weight] 100 parts by weight (solid content) of an aqueous dispersion obtained by emulsion polymerization of a monomer component
The present invention provides a method for producing an aqueous dispersion for anticorrosion paints, which comprises allowing a condensation reaction of at least one silicon compound selected from (II) alkoxysilane and cyclic siloxane to proceed in the presence of

The aqueous dispersion for anticorrosion paint of the present invention is an alkoxysilane and / or a cyclic siloxane in the presence of an aqueous dispersion obtained by polymerizing a monomer component containing the components (a) to (c). It can be produced by subjecting a silicon compound consisting of The component (a) used in the monomer component of the present invention is an alkyl (meth) acrylate and / or an aromatic vinyl monomer.

As the alkyl (meth) acrylate,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate,
Examples thereof include t-butyl (meth) acrylate, amyl (meth) acrylate, i-amyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and n-octyl (meth) acrylate, and preferably. An alkyl group having 1 to 8 carbon atoms, more preferably methyl methacrylate, ethyl (meth) acrylate or butyl (meth) acrylate.

As the aromatic vinyl monomer, for example, styrene, α-methylstyrene, 4-methylstyrene, 2
-Methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, 4-ethylstyrene, 4-ethoxystyrene, 3,4-dimethylstyrene, 2-chlorostyrene, 3-chlorostyrene, 4
-Chloro-3-methylstyrene, 4-t-butylstyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, 1-vinylnaphthalene, divinylbenzene and the like can be mentioned, with preference given to styrene.

The content of the component (a) is 40 to 99.5% by weight, preferably 50 to 95% by weight, more preferably 60 to 90% by weight, based on the total monomer components. When it is less than 40% by weight, the amount of coagulated product generated during emulsion polymerization increases, which is not preferable. On the other hand, if it exceeds 99.5% by weight, the anticorrosion property becomes poor.

Examples of the (b) ethylenically unsaturated carboxylic acid include, for example, itaconic acid, (meth) acrylic acid,
Examples thereof include fumaric acid, maleic acid, crotonic acid and derivatives thereof, and (meth) acrylic acid is preferably used. These (b) ethylenically unsaturated carboxylic acids may be used alone or in combination of two or more.

The content of the component (b) is 0.5 to 50% by weight, preferably 1 to 30% by weight, based on the total monomer components.
More preferably, it is 1 to 20% by weight. 0.5% by weight
If it is less than 50% by weight, the rust preventive property is deteriorated. On the other hand, if it exceeds 50% by weight, the amount of coagulated substances generated during emulsion polymerization increases, which is not preferable.

Further, the component (c) is the component (a) or (b) described above.
It is an ethylenically unsaturated monomer copolymerizable with the components, and examples thereof include hydroxymethyl (meth) acrylate, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, and hydroxyamyl (meth). ) Acrylate, hydroxyalkyl (meth) acrylate such as hydroxyhexyl (meth) acrylate; Epoxy compound such as allyl glycidyl ether, glycidyl (meth) acrylate, methylglycidyl (meth) acrylate; Ethylene glycol di (meth) acrylate, diethylene glycol di ( (Meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate , Dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetrapropylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, trimethylolpropane tri ( Polyfunctional monomers such as (meth) acrylate and pentaerythritol tetra (meth) acrylate;

(Meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth)
Acid amide compounds such as acrylamide, N-butoxymethyl (meth) acrylamide, N, N'-methylenebisacrylamide, thai acetone acrylamide, maleic acid amide, maleimide; vinyl compounds such as vinyl chloride, vinylidene chloride, fatty acid vinyl ester; tri Fluorine atom-containing monomers such as fluoroethyl (meth) acrylate and pentadecafluorooctyl (meth) acrylate; γ-methacryloylpropane trimethoxysilane, silicone compounds such as reactive silicone such as silaplane FM0711 manufactured by Chisso Corporation And the like. These can be used alone or in combination of two or more. Preferred examples of the component (c) include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylamide, and N-methylol (meth) acrylamide.

The content of the component (c) is 0 to 59.5% by weight, preferably 5 to 40% by weight, based on the total monomer components.
More preferably, it is 10 to 20% by weight. When the amount of the component (c) exceeds 59.5% by weight, the water resistance is deteriorated or the amount of coagulated substances generated during emulsion polymerization increases, which is not preferable.

The emulsion polymerization in the present invention can be carried out under ordinary emulsion polymerization conditions. For example, a monomer component in an aqueous medium, a crosslinking agent used as necessary, an emulsifier,
A polymerization initiator, a chain transfer agent, a chelating agent, a pH adjusting agent and the like are added, and a polymerization reaction is performed at a temperature of 30 to 100 ° C. for about 1 to 30 hours. Here, as the emulsifier used as necessary, anionic, nonionic, or anionic-nonionic combinations are used, and in some cases amphoteric surfactants and cationic surfactants are used. Can be used.

Examples of the anionic emulsifier include higher alcohol sulfuric acid ester sodium salt, alkylbenzene sulfonic acid sodium salt, succinic acid dialkyl ester sulfonic acid sodium salt, alkyl diphenyl ether disulfonic acid sodium salt and the like. Among these, dodecylbenzene sulfonic acid sodium salt, lauryl sulfate sodium salt, polyoxyethylene alkyl (or alkylphenyl) ether sulfate and the like are preferably used. As a nonionic emulsifier,
For example, polyoxyethylene alkyl allyl ether and the like can be mentioned. Generally, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, etc. are used as the nonionic emulsifier.

Lauryl bentine is suitable as the amphoteric emulsifier. As the cationic surfactant, alkylpyridinyl chloride, alkylammonium chloride and the like can be used. Furthermore, so-called reactive emulsifiers that are copolymerizable with the above-mentioned monomer components, such as sodium styrene sulfonate and sodium allylalkyl sulfonate, may also be used as emulsifiers. The amount of the emulsifier used is usually 0 to 5 parts by weight per 100 parts by weight of the monomer component, but a soap-free system and a system using a reactive emulsifier are preferable from the viewpoint of water resistance.

As the polymerization initiator, for example, water-soluble persulfate, hydrogen peroxide and the like can be used, and in some cases, they can be used in combination with a reducing agent. Examples of the reducing agent include sodium pyrobisulfite, sodium hydrogen sulfite, sodium thiosulfate, L-ascorbic acid and salts thereof, sodium formaldehyde sulfoxylate, and the like.

Further, an oil-soluble polymerization initiator such as 2,
2'-azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis-2,4-dimethylvaleronitrile, 1,1'- Azobis-cyclohexane-1-carbonitrile, benzoyl peroxide, dibutyl peroxide, cumene hydroperoxide and the like can be used by dissolving them in a monomer or a solvent. Preferred oil-soluble polymerization initiators include cumene hydroperoxide, isopropylbenzene hydroperoxide, paramenthane hydroperoxide, azobisisobutyronitrile, benzoyl peroxide, t-butyl hydroperoxide, 3,5,5- Examples thereof include trimethylhexanol peroxide and t-butylperoxy (2-ethylhexanoate). The amount of these polymerization initiators used is 0.1 to 100 parts by weight of the monomer component.
It is about 3 parts by weight.

As the chain transfer agent, halogenated hydrocarbons (eg chloroform, bromoform), mercaptans (eg n-dodecyl mercaptan, t-dodecyl mercaptan, n-octyl mercaptan), xanthogens (eg dimethylxanthogendiene). Sulfide, diisopropyl xanthogen disulfide), terpenes (eg, dipentene, terpinolene), α
-Methylstyrene dimer [2,4-diphenyl-4-
Methyl-1-pentene (a ₁ ), 2,4-diphenyl-
4-methyl-1-pentene (a _2), and 1-1-3
- trimethyl-3 consists of at least one phenylindane (a _3), preferably (a ₁₎ / (a ₂₎ and / or (a ₃₎ (weight ratio) = 40 to 100 / 0-6
0], unsaturated cyclic hydrocarbon compounds (for example, 9,10-
Dihydroanthracene, 1,4-dihydronaphthalene,
Indene, 1,4-cyclohexadiene), an unsaturated heterocyclic compound (eg, xanthene, 2,5-dihydrofuran) and the like can be mentioned. The amount of the chain transfer agent used is about 0 to 5 parts by weight per 100 parts by weight of the monomer component.

Examples of chelating agents include glycine, alanine, ethylenediaminetetraacetic acid, and p
Examples of the H adjuster include sodium carbonate, potassium carbonate, sodium hydrogen carbonate, ammonia and the like. The amount of the chelating agent and the pH adjusting agent used is 0 to 0.
It is about 1 part by weight and 0 to 3 parts by weight.

As a solvent used as necessary during emulsion polymerization, a small amount of methyl ethyl ketone, acetone, tetrahydrofuran, etc. may be used as long as the workability, disaster prevention safety, environmental safety and production safety are not impaired. Trichlorotrifluoroethane, methyl isobutyl ketone, dimethyl sulfoxide, toluene, dibutyl phthalate,
Methylpyrrolidone, ethyl acetate, alcohols, cellosolves, carbinols and the like are used. The amount of this solvent used is about 0 to 10 parts by weight per 100 parts by weight of the monomer component.

The emulsion polymerization in the present invention is carried out by a known method,
For example, a method of charging all the monomer components in a batch to the reaction system, a method of charging a part of the monomer components and reacting, and a method of charging the remaining monomer components continuously or dividedly, monomer It can be carried out by a method of continuously charging the components. The glass transition temperature (Tg) of the copolymer in the aqueous dispersion (I) thus obtained is -40 to 90.
° C, preferably -20 to 70 ° C, more preferably 0 to
It is 50 ° C. If the temperature is less than -40 ° C, the hardness is poor, while 9
If it exceeds 0 ° C, the anticorrosion property becomes poor. The toluene insoluble content of the copolymer in the obtained aqueous dispersion (I) is 98% by weight or less, preferably 40 to 98% by weight, more preferably 60 to 95% by weight, particularly preferably 70% by weight.
~ 95% by weight. If it exceeds 98% by weight, the water resistance will be poor. Furthermore, the acid value of the copolymer in the obtained aqueous dispersion (I) is preferably 3 to 330,
More preferably 7 to 200, particularly preferably 7 to 13
It is 0. If it is less than 3, the rust resistance may be poor, while
If it exceeds 330, the amount of coagulated product generated during emulsion polymerization increases, which is not preferable. Furthermore, the weight average molecular weight of the copolymer in the aqueous dispersion (I) obtained by emulsion polymerization is preferably 200,000 or more, more preferably 300,000 or more, and particularly preferably 400,000 or more. If it is less than 200,000, the water resistance may not be sufficient.

The silicon compound (II) in the present invention has the general formula R _n Si (OR ') _4-n [wherein R is an organic group having 1 to 8 carbon atoms and R'is an organic group having 1 to 5 carbon atoms]. Alkyl group or carbon number 1
~ 4 acyl group, n represents an integer of 0-3. ] Alkoxysilane represented by R _m SiO _{(4-m) / 2} [wherein R is
Is the same as above, and m is a number from 0 to 3. ] It is at least 1 sort (s) chosen from the cyclic siloxane represented by these. In the formula, R is an organic group having 1 to 8 carbon atoms, and examples thereof include an alkyl group such as a methyl group, an ethyl group, an n-propyl group, and an i-propyl group, and a γ-chloropropyl group, a vinyl group, 3, 3,3-trichloropropyl group, γ-glycidoxypropyl group, γ-methacryloxypropyl group, γ
Examples thereof include a mercaptopropyl group, a phenyl group, a 3,4-epoxycyclohexylethyl group, and a γ-aminopropyl group. Further, in the formula, R ′ is an alkyl group having 1 to 5 carbon atoms or an acyl group having 1 to 4 carbon atoms, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an n-butyl group and a sec-butyl group. Group, t-butyl group, acetyl group and the like.

When the carbon number of R or R'in the formula increases, the water solubility decreases, and the aqueous dispersion (I) as a seed is reduced.
It is not preferable because the absorption rate of organosilane with respect to is decreased. Specific examples of these organosilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilanene, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and n-propyl. Trimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane , 3,
3,3-trifluoropropyltrimethoxysilane, 3,
3,3-trifluoropropyltriethoxysilane, γ-
Glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxy Silane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-aminopropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane , Diethyldimethoxysilane and the like, preferably tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane. Emissions, dimethyldimethoxysilane, dimethyl diethoxy silane.

As the cyclic siloxane, hexaphenylcyclotrisiloxane, octaphenylcyclotetrasiloxane, tetravinyltetramethylcyclotetrasiloxane, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, pentamethylcyclotetrasiloxane, hexamethyl In addition to cyclic compounds such as cyclotetrasiloxane, tetramethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and trimethyltriphenylcyclotrisiloxane, linear or branched organosiloxanes can be mentioned. . These organosiloxanes may be used alone or in combination of two or more, and other metal alkoxides such as titanium and aluminum may be used in combination. Also,
If necessary, a known silane coupling agent can be used in combination. Furthermore, these organosilanes can be used after being dissolved in an organic solvent, if necessary.

The amount of the silicon compound (II) used in the present invention is 0.1 to 500 parts by weight, preferably 0.5 to 250, per 100 parts by weight (solid content) of the aqueous dispersion (I) component.
Parts by weight, more preferably 1.0 to 100 parts by weight. If the amount is less than 0.1 part by weight, the rust resistance is poor, while 50
If it exceeds 0 parts by weight, the adhesion and storage stability will be poor.

In the present invention, the method of absorbing the silicon compound in the aqueous dispersion (I) can be easily achieved by adding the silicon compound to the aqueous dispersion (I) and stirring it well. In order to efficiently absorb the silicon compound into the aqueous dispersion (I) serving as a seed, a solvent having a solubility in water of 10 ⁻³ wt% or less may be absorbed into the aqueous dispersion (I) in advance, if necessary. It is also possible to set it. Further, in order to prevent the reaction from proceeding in a state where the absorption of the silicon compound is not sufficient, the aqueous dispersion (I) is adjusted to pH 4 to 10, preferably pH 5 to 9, and more preferably pH 6 to 8, and the temperature is 90. ℃ or less, preferably 70 ℃ or less, more preferably 50 ℃ or less, particularly preferably 30 ℃ or less,
It is desirable to add and absorb a silicon compound.

The condensation reaction of the silicon compound added to the aqueous dispersion (I) can be easily controlled by changing the reaction temperature and the hydrogen ion concentration, and the polymerization degree of polysiloxane can be adjusted. The condensation reaction of the silicon compound can be carried out at a temperature of 30 ° C. or higher, preferably 50 ° C. or higher, more preferably 70 ° C. or higher. The silicon compound absorbed in the aqueous dispersion (I) is 5% by weight or more, preferably 10% by weight or more, and more preferably 30% by weight or more of the total silicon compounds used.

The aqueous dispersion for rust preventive coating composition of the present invention may exhibit further excellent rust preventive property, adhesion and water resistance by adding a crosslinking agent. Here, as the cross-linking agent,
Amino resin, phenol resin, epoxy resin, alkyd resin, thermosetting resin such as unsaturated polyester, isocyanate compound, blocked isocyanate compound, polyhydric alcohol, aziridine compound, organic crosslinking agent such as oxazoline compound, metal or metal compound, etc. Inorganic cross-linking agents may be mentioned. These crosslinkers are
Usually, it can be used at a curing temperature of 0 to 280 ° C., but amino resins, phenol resins, block isocyanate compounds and the like are preferably used at a curing temperature of 100 ° C. or higher.

Examples of the amino resin include a completely alkyl-type methylated melamine resin such as a hexamethoxymethylated melamine resin, a partially alkylated methylated melamine resin, a benzoguanamine resin, and an alkyl etherified urea resin. Examples of the isocyanates and blocked isocyanates include tolylene diisocyanate and its hydrogenated products and adducts, diphenylmethane diisocyanate and its hydrogenated products, triphenylmethane triisocyanate and its hydrogenated products, hexamethylene diisocyanate, xylylene diisocyanate and its hydrogenated products. , Isophorone diisocyanate, dianisidine diisocyanate, tolidine diisocyanate, blocked polyisocyanate having an isocyanate group blocked, and any mixture thereof.

Examples of the phenol resin include dimethylol resin, polymethylolphenol resin, phenolformamide resin, methylolphenolformamide resin, dimethylolphenolformamide resin and the like. Epoxy resins include eletin glycol, diglycidyl ether, hexanediol, diglycidyl ether, neopentyl glycol diglycidyl ether, glycerin diglycidyl ether, glycerin polyglycidyl ether, glycerin polyglycidyl ether, sorbitol polyglycidyl ether. Polyglycidyl ether of polyhydric alcohol such as ether, hydrogenated bisphenol A / diglycidyl ether or bisphenol A / diglycidyl ether, or p-
Oxybenzoic acid glycidyl ether, phthalic acid glycidyl ester or hexahydrophthalic acid, glycidyl ester, and further hydantoin ring-containing epoxy resin,
And a vinyl-based polymer having an epoxy group in its side chain may be used.

As the metal compound, oxides or salts of metals such as zinc, zirconium, magnesium, copper, iron, cobalt, nickel, aluminum, cadmium and titanium are carbonic acid, acetic acid, formic acid, glutaric acid, benzoic acid, and oxalic acid. It is obtained by dissolving it in an acid such as an acid, or by adjusting the pH of an aqueous solution of these acid and a polyvalent metal compound to 7 to 11 with ammonia, amine, etc., and in the form of a metal ion. Things can also be included. This polyvalent metal compound is zinc ammonium carbonate, ammonium carbonate zirconate, zinc,
It is an oxide or salt of zirconium. Examples of the amine capable of forming a complex are morpholine, monoethanolamine, ethylenediamine, diethylaminoethanol and the like. In addition, general complexing agents such as complexanes such as diethyldiaminetetraacetic acid, glycine, and alanine can be used.

The aziridine compound is tris-
2,4,6- (1-aziridinyl) -1,3,5-triazine, tris [1- (2-methyl) aziridinyl] phosphine oxide, hexa [1- (2-methyl) aziridinyl] triphosphatriazine, etc. Can be mentioned. Examples of the oxazoline-based crosslinking agent include K-1000 and 2000 series manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd.

The amount of the cross-linking agent used is the water dispersion 1 for anticorrosion paint.
The amount is 100 parts by weight or less, preferably 1 to 70 parts by weight, and more preferably 3 to 50 parts by weight with respect to 00 parts by weight (solid content). If it exceeds 100 parts by weight, rust resistance and storage stability may be poor. The cross-linking agent may be added in the process for producing the aqueous dispersion for rust-preventive paint, or may be added in the step of polymerizing the aqueous dispersion for rust-preventive paint, and the rest may be added after production.

Any known rust preventive pigment may be used in the present invention. For example, as lead-based pigments, red lead, lead suboxide, cyanamide lead, calcium leadate, etc., as chromate pigments, zinc chromate, basic chromate, barium chromate, etc., basic lead sulfate, strontium chromate, Graphite, zinc phosphate, calcium phosphate, zinc white, ferrite, scaly iron oxide, aluminum phosphomolybdate, zinc molybdate, lead phosphate, calcium molybdate, barium metaborate, metal salts of organic nitro compounds, lead cyanamide lead calcium , Lead silicate, barium molybdate, chromium phosphate and the like.

The following additives may be added to the aqueous dispersion for anticorrosion paint of the present invention depending on the purpose. The amount of this additive added is 50 parts by weight or less, preferably 40 parts by weight or less, based on 100 parts by weight (solid content) of the aqueous dispersion for anticorrosion paint. As the additive, first, in order to improve film-forming property and wettability, alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, amyl alcohol, and hexyl alcohol,
Organic solvents such as methyl cellosolve, ethyl cellosolve, propyl cellosolve, butyl cellosolve, hexyl cellosolve, methyl carbitol, ethyl carbitol, methyl cellosolve acetate, ethyl cellosolve acetate and tributoxymethyl phosphate can be used. The amount of the organic solvent used is 0 to 20% by weight, preferably 0 to 10% by weight, more preferably 0 to 5% by weight, of the aqueous dispersion for anticorrosive paint.

As additives other than the above-mentioned additives,
In addition to water-soluble polyester resins, water-soluble or water-dispersible epoxy resins, water-soluble or water-dispersible acrylic resins, carboxylated aromatic vinyl resins such as styrene-maleic acid resins, urethane resins, etc. Further, a swelling agent, a defoaming agent, a wetting agent, a leveling agent, a pigment and the like can be used. The solid content concentration of the aqueous dispersion for anticorrosion paint of the present invention is usually 10 to 6
It is 0% by weight. The rust preventive coating aqueous dispersion of the present invention forms a film excellent in rust resistance, water resistance, hardness, adhesion, etc., and therefore, rust prevention of metal such as pre-coated metal, aluminum sash, can and metal parts. Excellent effect as a paint.

[0038]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples as long as the gist thereof is not exceeded. In the examples, parts and percentages are by weight. Further, the measurement of various physical properties in Examples was based on the following methods.

[0039] The rust resistance JIS K5400 salt spray test method, were evaluated after 200 hours. After immersing the water resistant test piece in water at 25 ° C. for 5 days, the gloss retention of the coating film was measured. Pencil hardness: Measured using a pencil scratch tester according to JIS G3312. Adhesion In accordance with JIS G3312, 100 cross-cut tests of 1 mm square were performed, and the peeled state was confirmed with cellophane tape.
It is indicated by the number of adhesions in 100 pieces. Storage stability The state of the rust preventive paint aqueous dispersion after storage for 3 months was confirmed.

Example 1 A stainless steel autoclave equipped with a stirrer, a thermometer and a monomer addition pump was equipped with a heater and a nitrogen gas introducing device, and 120 parts of water and 1 part of sodium alkylbenzenesulfonate were attached to the autoclave. 0.3 part of ammonium persulfate was charged, the gas phase part was replaced with nitrogen gas for 15 minutes, and the temperature was raised to 75 ° C. Then, from another container n
A mixture of 38 parts of butyl acrylate, 30 parts of methylmethacrylate, 30 parts of threthin and 2 parts of methacrylic acid was continuously added over a required time of 3 hours. After the addition was completed, the mixture was further aged at 85 to 95 ° C for 2 hours, cooled to 25 ° C, and p
It was adjusted to H8 to obtain an aqueous dispersion (I).

Next, 10 parts of methyltriethoxysilane was added to the aqueous dispersion (I) which serves as a seed, and the mixture was stirred for about 1 hour, further heated to 70 ° C. and subjected to a condensation reaction for 3 hours. Then, the mixture was cooled, the solid content concentration was adjusted to 45% with water, and then filtered through a 200-mesh wire net. The average particle size of the obtained water dispersion for anticorrosion paint was 0.14 μm. The average particle size was measured using a Nisizer manufactured by Coal Tar Co. The oxidation of the obtained water dispersion for anticorrosion paint was 11, and the conversion of organosilane was 99.
%Met. While stirring 100 parts (solid content) of this aqueous dispersion for anticorrosion paint, 50% of ethyl carbitol was added.
20 parts of the aqueous solution was added, and a plasticizer [Chisso Co.
Manufactured by Texanol CS-12] was added, and the mixture was stirred for 1 hour or more. In addition, rutile type titanium white [Death Perth White SD manufactured by Dainippon Ink and Chemicals, Inc.
-7021, non-volatile content 70%] was added and mixed in a boat mill for 2 hours to obtain a rust-preventive paint. This rust-preventive paint was applied to a zinc iron plate (0.8 mm thickness) using a bar coater so that the film thickness was about 50 μm, and baked at 150 ° C. for 10 minutes to give a test piece. Water resistance, pencil hardness, adhesion, and storage stability were evaluated. The results are shown in Table 1.

Example 2 An anticorrosive paint and a test piece were obtained in the same manner as in Example 1 except that the charged amount of the monomer was changed as shown in Table 1. The results are shown in Table 1.

Example 3 A rust preventive paint and a test piece were obtained in the same manner as in Example 1 except that the amount of methyltriethoxysilane charged was changed as shown in Table 1. The results are shown in Table 1.

Example 4 While stirring 100 parts (solid content) of the aqueous dispersion for rust preventive paint of Example 1, a melamine resin composition [20 parts of Cymel 303, manufactured by Mitsui Cyanamid Co., Ltd., 262 of Fujii Yoshitsusho Co., Ltd.] was stirred.
5A ammonia salt 0.2 parts and water 8 parts] were gradually added, and then a 50% aqueous solution of ethylcarbitol was added for 20 minutes, and the mixture was stirred for 1 hour or more. Then, rutile type titanium white was blended in the same manner as in Example 1 to obtain an anticorrosive paint and a test piece. The results are shown in Table 1.

Comparative Examples 1 and 2 Anticorrosion paints and test pieces were obtained in the same manner as in Example 1 except that the amount of methyltriethoxysilane charged was changed as shown in Table 1. The results are shown in Table 1.
From the results shown in Table 1, when the amount of the organosilane is less than 0.1 part, the antirust property is poor, while when it exceeds 500 parts, the antirust property is
It can be seen that the adhesiveness and storage stability are poor.

Comparative Examples 3 to 5 Anticorrosion paints and test pieces were obtained in the same manner as in Example 1 except that the kinds of monomers and the charged amount were changed as shown in Table 1. The results are shown in Table 1. From the results in Table 1, it can be seen that if the total amount of the acrylic acid alkyl ester and the aromatic vinyl monomer exceeds 99.5 parts, the rust preventive property is poor, and if the total is less than 40, the polymerization stability is poor. Further, it can be seen that if the amount of the ethylenically unsaturated carboxylic acid is less than 0.5 part, the rust prevention property is poor, and if it exceeds 50 parts, the polymerization stability is poor.

[0047]

[Table 1]

[0048]

EFFECT OF THE INVENTION The method for producing an aqueous dispersion for rust preventive paints of the present invention is a conventional solvent type, solvent-containing aqueous type rust preventive paint without impairing the original excellent properties, rust resistance, water resistance,
It has excellent adhesion and storage stability, and can significantly reduce the content of organic solvents, so it can be used for metal coatings that require rust prevention properties such as pre-coated metal, aluminum sashes, cans and metal parts. it can.

Front page continuation (72) Inventor Akio Hiraharu 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd.

Claims (1)

[Claims] 1. (I) (a) Alkyl (meth) acrylate and / or aromatic vinyl monomer 40-99.5
% By weight, (b) 0.5 to 5 ethylenically unsaturated carboxylic acid
0% by weight, and 0 to 59.5% by weight of other ethylenically unsaturated monomers copolymerizable with components (a) and (b) (where (a) + (b) + (c ) = 100% by weight]
Aqueous dispersion 1 obtained by emulsion polymerization of a monomer component consisting of
A method for producing an aqueous dispersion for anticorrosion paints, which comprises advancing a condensation reaction of at least one silicon compound selected from (II) alkoxysilane and cyclic siloxane in the presence of 100 parts by weight (solid content).