JPH10316903A - Stainproofing agent for water-based coating material and water-based coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a stainproofing agent which, when added to a water-based coating composition, can give a composition having a long pot life and excellent stability by heating a hydrophilic organic solvent solution containing a hydroxy polymer, a specified amount of a specified atkoxysilane and water in an acidic atmosphere until a solution having an at most specified content of a specified primary alcohol is formed. SOLUTION: This agent comprises a solution obtained by heating a hydrophilic organic solvent solution containing a hydroxy polymer (e.g. methyl methacrylate/butyl methacrylate/2-hydroxyethyl methacrylate copolymer) or both this polymer and a polyalkylene glycol, an alkoxysilane having at least two 2-4 C alkoxyl groups and water in an acidic atmosphere. This solution should have a content of Si derived from the alkoxysilane of 50-600 pts.wt. (in terms of the SiO2 ), per 100 pts.wt. solid matter derived from the hydroxiy polymer or both this polymer and the alkylene glycol, and a content of a 1-4 C primary alcohol content of at most 5 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stain resistance imparting agent for water-based paint and an aqueous paint composition comprising the stain resistance-imparting agent.

[0002]

2. Description of the Related Art At present, as a paint for outdoor exterior,
Paints such as acrylic urethane paints and fluorine paints are used because of their excellent weather resistance. However, these paints lose their appearance due to accumulation of contaminants or rain streak-like dirt on the coating film surface due to automobile exhaust gas, dust, iron powder, acid rain, sun rays and the like. Had the problem that The present inventors, as a means to improve this problem of stain resistance, in a coating prepared from a hydroxyl group-containing fluororesin, a partially hydrolyzed condensate of alkoxysilane or an alkoxysilane partially bonded to a hydroxyl group-containing fluororesin. A method of adding a stain resistance-imparting agent comprising a partially hydrolyzed condensate has been proposed (JP-A-8-26).
No. 9385, hereinafter referred to as the prior invention). On the other hand, in recent years, from the viewpoints of environmental pollution and safety and health, water-based paints have been increasingly used, and water-based emulsions have been frequently used in place of conventional organic solvent-based paints. Many studies have been made on improving the water resistance and chemical resistance of emulsion paints, but they are still insufficient with respect to stain resistance. However, the stain resistance-imparting agent proposed in the previous invention by the present inventor was invented on the premise of using an organic solvent-based paint. There were problems such as a short pot life and aggregation of the emulsion depending on the type. The present inventors have found that when incorporated into an aqueous coating composition, the coating composition has a sufficient pot life, the resulting composition has excellent stability, and the coating film has excellent stain resistance. The inventor has conducted intensive studies to find a water-based coating composition containing the imparting agent and the stain resistance-imparting agent.

[0003]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that when the stain resistance-imparting agent of the above invention is blended with an aqueous paint, the cause of the extremely short pot life is as follows. In the production of the stain resistance imparting agent, a lower alcohol component generated when the alkoxysilane is condensed, in particular, having 4 carbon atoms
The following primary alcohols were found out, and after further investigation with the idea that reducing this would result in a stain resistance imparting agent applicable to aqueous paints, the present invention was completed. is there. Hereinafter, the present invention will be described in detail.
In this specification, acrylic acid or methacrylic acid is referred to as (meth) acrylic acid, and acrylate or methacrylate is referred to as (meth) acrylate,
Acrylamide or methacrylamide is called (meth) acrylamide.

[0004]

BEST MODE FOR CARRYING OUT THE INVENTION

1. Stain resistance-imparting agent for water-based paint The stain resistance-imparting agent for water-based paint of the present invention (hereinafter sometimes simply referred to as stain resistance-imparting agent) is a hydroxyl-containing polymer or the hydroxyl-containing polymer and polyalkylene glycol,
A solution obtained by heating a hydrophilic organic solvent solution containing an alkoxysilane having two or more alkoxy groups having 2 to 4 carbon atoms and water under an acidic atmosphere, and containing Si derived from the alkoxysilane. The amount is 50 to 600 parts by weight in terms of SiO ₂ with respect to 100 parts by weight of the total amount of the hydroxyl group-containing polymer or the solid content derived from the hydroxyl group-containing polymer and the polyalkylene glycol, and further has 4 or less carbon atoms. In which the content of the primary alcohol is 0 to 5% by weight. Hereinafter, each component will be described.

[0005] 1-1. Hydroxyl-containing polymer The hydroxyl-containing polymer used in the present invention may be any of various polymers as long as it has a hydroxyl-containing monomer as an essential component. Is 10
It is preferably 30 mol% to 30 mol%. This ratio is 10
When the amount is less than mol%, the polymer may precipitate in the obtained stain resistance imparting agent and the solution may become turbid. On the other hand, when the amount exceeds 30 mol%, the coating of the composition containing the stain resistance imparting agent may be performed. The water resistance of the film may decrease. The number-average molecular weight of the hydroxyl group-containing polymer is preferably from 2,000 to 50,000 in terms of polystyrene by gel permeation chromatography (hereinafter referred to as GPC), and more preferably from -20 to 60 ° C. in glass transition temperature.

Further, the hydroxyl group-containing polymer may be a blend of two or more kinds of hydroxyl group-containing polymers in any ratio in which their compatibility is good.

In the present invention, since the coating film of the composition containing the stain resistance imparting agent can be made to have excellent weather resistance, the hydroxyl group-containing polymer may be a hydroxyl group-containing acrylic polymer or a hydroxyl group-containing fluorine polymer. It is preferred to use coalescence.

The hydroxyl group-containing acrylic polymer has a hydroxyl group at a terminal or a side chain, and can be copolymerized with a hydroxyl group-containing monomer, a (meth) acrylic acid ester and, if necessary, with these monomers. Copolymers with other monomers and the like can be mentioned.

The hydroxyl group-containing monomers include 2-hydroxyethyl (meth) acrylate and 3-hydroxy (meth) acrylate.
Hydroxyalkyl acrylates such as hydroxypropyl and 4-hydroxybutyl (meth) acrylate; hydroxyl-containing (meta) such as N-methylol (meth) acrylamide, 2-hydroxyethyl (meth) acrylamide and 4-hydroxyethyl (meth) acrylamide ) Acrylamide; 2-hydroxyethyl vinyl ether, 2-
Hydroxyalkyl vinyl ethers such as hydroxypropyl vinyl ether and 4-hydroxybutyl vinyl ether; allyl alcohol; cinnamon alcohol; hydroxyalkyl crotonates such as 2-hydroxyethyl crotonate, 2-hydroxypropyl crotonate and 4-hydroxybutyl crotonate; Compounds obtained by further ring-opening addition of ε-caprolactam and ethylene oxide to these monomers; and unsaturated carboxylic acids such as (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid and itaconic acid, and ethylene glycol. , Ethylene oxide,
Reaction products with polyhydric alcohols such as propylene glycol, propylene oxide, butylene glycol, cyclohexane dimethanol, glycerin, and trimethylolpropane are exemplified. Two or more hydroxyl group-containing monomers can be used in combination.

The (meth) acrylic acid ester is other than the above-mentioned hydroxyl group-containing (meth) acrylic acid ester, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylate. ) Butyl acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, tri (meth) acrylate Fluoroethyl, pentafluoropropyl (meth) acrylate, glycidyl (meth) acrylate, diethylaminoethyl (meth) acrylate, 3-ethoxysilylpropyl (meth) acrylate, and the like.

Other monomers copolymerizable with these monomers include (meth) acrylonitrile, (meth) acrylamide, styrene, α-methylstyrene, (meth) acrylic acid, maleic acid, fumaric acid, Itaconic acid,
Examples include vinyl acetate and vinyl propionate.

The hydroxyl group-containing acrylic polymer is preferably produced by a solution polymerization method using the above-mentioned monomer and using a peroxide radical initiator or an azo radical initiator. In this case, aromatic, ketone, ester and alcoholic organic solvents can be used as the polymerization solvent.

Examples of the hydroxyl group-containing fluorine-containing polymer include a hydroxyl group-containing monomer, a fluoroolefin monomer and, if necessary, a copolymer of such a monomer with another monomer which can be copolymerized with the monomer. And a solvent-soluble polymer is preferable.

As the hydroxyl group-containing monomer, those having excellent copolymerizability with a fluoroolefin monomer described later can be preferably used. Specifically, the (meth) acrylic acid mentioned above for the hydroxyl group-containing acrylic polymer can be used. Hydroxyalkyl,
In addition to hydroxyl group-containing (meth) acrylamide, hydroxyalkyl vinyl ether and hydroxyalkyl crotonate, there may be mentioned hydroxyl group-containing allyl ethers such as 2-hydroxyethyl allyl ether, 4-hydroxyethyl allyl ether and diethylene glycol monoallyl ether. Further, compounds obtained by ring-opening addition of ε-caprolactam and ethylene oxide to these hydroxyl group-containing monomers can also be used.

Examples of the fluoroolefin monomer include monofluoroethylene, difluoroethylene, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene, among which chlorotrifluoroethylene is used. Is preferable in terms of excellent copolymerizability and handleability. The copolymerization ratio of the fluoroolefin monomer is preferably 30 to 60 mol% of all monomers. When the amount is less than 30 mol%, the weather resistance of the coating film of the composition containing the stain resistance-imparting agent decreases, and when the amount is 60 mol% or more, the solubility in a solvent may decrease. A more preferred amount is 4
0 to 60 mol%.

If necessary, other monomers copolymerizable with the above-mentioned monomers can be introduced into the hydroxyl group-containing fluoropolymer in an amount of up to 60 mol%. Examples of other monomers include carboxylic acid vinyl esters, vinyl ethers, unsaturated carboxylic acids, and anhydrides thereof. As vinyl carboxylates,
Vinyl acetate, vinyl propionate, vinyl caproate,
Vinyl pivalate, veova-9 and veova-10
(Manufactured by Shell Chemical), such as aliphatic vinyl esters, vinyl cyclohexanecarboxylates such as vinyl cyclohexanecarboxylate and vinyl 4-t-butylcyclohexanecarboxylate, and vinyl benzoate and pt-butylbenzoic acid. And vinyl aromatic carboxylate. Specific examples of vinyl ethers include alkyl vinyl ethers such as ethyl vinyl ether and butyl vinyl ether, and cycloalkyl vinyl ethers such as cyclohexyl vinyl ether. As unsaturated carboxylic acids, acrylic acid, crotonic acid, maleic acid,
Examples include itaconic acid and vinyl acetic acid. If the proportion of the unsaturated carboxylic acid in the polymer is too large, the water resistance of the coating film of the composition containing the stain resistance-imparting agent may be reduced.

In addition to these, olefins such as ethylene, propylene and 1-butene; hydrolyzable silyl group-containing monomers such as vinyltriethoxysilane and 3-triethoxysilylpropyl (meth) acrylate; Vinyl and vinylidene chloride may be used.

The hydroxyl group-containing fluoropolymer is produced by copolymerizing the monomers by a known polymerization method, for example, a solution polymerization method described in JP-A-3-231906. Good.

1-2. An alkoxy group having 2 to 4 carbon atoms
Alkoxysilanes having 2 or more alkoxysilanes having 2 or more alkoxy groups having 2 to 4 carbon atoms (hereinafter simply referred to as alkoxysilanes) used in the present invention include monomers, oligomers, and polymers having alkoxysilyl groups. Specifically, tetraethoxysilane (hereinafter abbreviated as TEOS), tetrapropoxysilane, tetrabutoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, vinyltriethoxysilane, methyltriethoxysilane, phenyltriethoxysilane, γ- Examples thereof include chloropropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, and the like, and oligomers that are multimers of these alkoxysilanes. Oligomers of alkoxysilanes are commercially available, for example TEOS oligomers silicate 40 (average pentamer) and silicate 48 from Tama Chemical Co., Ltd., and ethyl silicate 4 TEOS oligomers from Colcoat Co., Ltd.
0 (average pentamer) and the like. Examples of the polymer having an alkoxysilyl group include one obtained by reacting one or both terminals of polyethylene glycol with an isocyanate group-containing silane coupling agent such as isocyanate group-containing trimethoxysilane and isocyanate group-containing triethoxysilane. . It is preferable to use a monomer or an oligomer as the alkoxysilane.

1-3. Method for producing stain resistance imparting agent for water-based paint The stain resistance imparting agent for a water-based paint of the present invention comprises a hydroxyl group-containing polymer or the hydroxyl group-containing polymer and a polyalkylene glycol, and an alkoxy group having 2 to 4 carbon atoms. This is a solution obtained by heating a hydrophilic organic solvent solution containing at least one alkoxysilane and water under an acidic atmosphere. Acids used to bring the solution to an acidic atmosphere include inorganic acids such as hydrochloric acid, and organic acids such as acetic acid and p-toluenesulfonic acid. As the mixing ratio of the acid, a ratio at which the pH of the solution is about 1 to 4 is preferable. Water is blended to promote the hydrolysis-condensation reaction of the alkoxysilane. In the present invention, the proportion of water is two alkoxyalkoxysilanes in the alkoxysilane in order to aim at a linear alkoxysilane condensate. 0.0
Preferably, 5 to 1 equivalent of water is added. For example, TEO having four alkoxy groups as alkoxysilane
When S is used, 2 mol of water is added to 1 mol of TEOS.
1 equals 1 equivalent. The reaction temperature and reaction time in the hydrolysis reaction may be appropriately set according to the purpose, but preferably include 30 to 80 ° C. for 1 to 8 hours. The end point of the reaction is usually such that the amount of unreacted alkoxysilane in the reaction solution is traced by gas chromatography or the like, and the amount of unreacted alkoxysilane almost disappears or the amount of unreacted alkoxysilane does not change.
The stain resistance imparting agent obtained by the reaction was obtained by adding a partially hydrolyzed condensate of an alkoxysilane to a hydroxyl group in a hydroxyl group-containing polymer or a hydroxyl group-containing polymer and a polyalkylene glycol, and using an alcohol as a hydrophilic organic solvent. In this case, the solution is a solution obtained by adding a partially hydrolyzed condensate of an alkoxysilane to a hydroxyl group of an alcohol, a partially hydrolyzed condensate of an alkoxysilane, a partially hydrolyzed product of an alkoxysilane, and an unreacted alkoxysilane.

Since the condensation reaction can be preferably accelerated, an alkoxide of a metal consisting of a Group 3 element or a Group 4 element such as aluminum, titanium and zirconium can be added before or after heating.

In the present invention, after the condensation reaction, the reaction solution is neutralized, and when the obtained stain resistance-imparting agent is mixed with the aqueous dispersion of the polymer, the resin component does not precipitate. It is preferable because of its excellent pot life. Examples of the method of neutralization include a method in which a basic compound such as ammonia and ethylenediamine is mixed in the reaction solution, a method in which a basic ion exchange resin is mixed in the reaction solution, or a method in which the reaction solution is passed through the basic ion exchange resin. The method of passing the reaction solution through a basic ion exchange resin is preferred because the operation is simple.

The reaction solution is preferably concentrated for the purpose of adjusting the amount of the hydrophilic organic solvent in the stain resistance imparting agent and for reducing the primary alcohol having 4 or less carbon atoms to 0 to 5% by weight.
As a method for concentration, heating under reduced pressure or the like is available.

Examples of the hydrophilic organic solvent used in the above-mentioned production method include alcohol-based, ketone-based, ester-based and aromatic-based organic solvents. Among them, a hydroxyl group-containing polymer is excellent in solubility and is obtained. It is preferable to use an alcoholic organic solvent because the stain resistance imparting agent is excellent in the compoundability with the aqueous dispersion of the polymer. Alcohol-based organic solvents include methanol, ethanol,
In addition to alcohols such as isopropanol, propanol, butanol and diacetone alcohol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, ethylene glycol monobutyl ether,
Glycol ethers such as isoprene glycol monomethyl ether and isoprene glycol monoethyl ether can also be used. Among the alcohol-based organic solvents, it is possible to use an alcohol having 5 or more carbon atoms, when the obtained stain resistance-imparting agent is blended in the aqueous dispersion of the polymer,
This is preferable because the resin component does not precipitate. Two or more hydrophilic organic solvents can be used in combination.

It is preferable that the content of the hydrophilic organic solvent in the stain resistance imparting agent is 10% by weight or more from the viewpoint of excellent stability of the solution. However, the proportion of the primary alcohol having 4 or less carbon atoms, that is, methanol, ethanol, 1-propanol and 1-butanol in the stain resistance-imparting agent is determined when the stain resistance-imparting agent is incorporated into the aqueous dispersion of the polymer. To
Since the resin component precipitates to deteriorate the pot life and makes it difficult to emulsify the water-based coating composition, the content needs to be 0 to 5% by weight. The primary alcohol having 4 or less carbon atoms is
This is due to alcohol generated in the condensation reaction of alkoxysilane and alcohol when a primary alcohol having 4 or less carbon atoms is used as the hydrophilic organic solvent.

In the stain resistance-imparting agent, the content of Si derived from the charged alkoxysilane is calculated as SiO _{2 based on} 100 parts by weight of the solid content derived from the hydroxyl group-containing polymer or the hydroxyl group-containing polymer and the polyalkylene glycol. And it is necessary to be 50 to 600 parts by weight. This ratio can be adjusted by the amount of the hydroxyl group-containing polymer or the hydroxyl group-containing polymer and the charged amounts of the polyalkylene glycol and the alkoxysilane during the production of the stain resistance imparting agent. When the proportion is less than 50 parts by weight, the coating film of the obtained composition has poor stain resistance. On the other hand, when the proportion exceeds 600 parts by weight, the stain resistance imparting agent is added to the aqueous dispersion of the polymer. As a result, a resin component precipitates and the pot life is shortened.

In the present invention, it is preferable that the hydrolysis-condensation reaction is carried out in the presence of a polyalkylene glycol in addition to the hydroxyl group-containing polymer, since the stability of the obtained solution can be improved. In this case, as the polyalkylene glycol, a water-soluble polyalkylene glycol represented by polyethylene glycol and polypropylene glycol is preferably used, and polyethylene glycol is more preferable. The molecular weight of the polyalkylene glycol is preferably from 200 to 2,000 in terms of number average molecular weight from the viewpoint of solubility in the solvent used in the hydrolysis condensation reaction and compatibility with the hydroxyl group-containing polymer. In this case, the preferable blending ratio of the polyalkylene glycol is 200 parts by weight or less per 100 parts by weight of the hydroxyl group-containing polymer. If the amount exceeds 200 parts by weight, the weather resistance of the coating film of the composition containing the stain resistance imparting agent may decrease.

The solid content of the stain resistance imparting agent is preferably not more than 60% by weight in view of excellent stability of the partially hydrolyzed condensate of alkoxysilane. The stain resistance imparting agent obtained by the above reaction can be diluted with an organic solvent, if necessary. As the organic solvent, those similar to the above-mentioned hydrophilic organic solvents can be used. However, even in this case, the content of the primary alcohol having 4 or less carbon atoms in the solution needs to be 5% by weight or less.

2. Aqueous paint composition The second invention of the present invention is an aqueous paint composition containing the stain resistance-imparting agent, and specifically, the stain resistance imparting agent of the first invention is added to an aqueous dispersion of a polymer. And the like. Hereinafter, the aqueous dispersion of the polymer will be described.

2-1. Aqueous Dispersion of Polymer As the aqueous dispersion of the polymer used in the present invention, those generally used as aqueous coatings can be used. Examples of the polymer include an acrylic polymer, an acrylic silicone polymer, a polyurethane, a fluorinated polymer, an epoxy resin, and a polyester resin. The glass transition temperature of the polymer is preferably from 0 ° C to 80 ° C, more preferably from 20 ° C to 80 ° C. If the glass transition temperature of the polymer is less than 0 ° C., the adhesiveness remains in the dried coating film, so that even if a stain resistance imparting agent is added, the stain resistance effect may be hardly exhibited.
If the temperature exceeds ℃, cracks may easily occur in the coating film. The molecular weight of the polymer is preferably 10,000 to 5,000,000, more preferably 100,000 to 1,000, as a number average molecular weight in terms of polystyrene by GPC.
000. When the number average molecular weight is less than 10,000, the coating film of the obtained composition may become brittle, while when it exceeds 5,000,000, the film forming property of the coating film of the obtained composition is reduced.

The aqueous dispersion of the polymer in the present invention may be any one obtained by emulsion-polymerizing a monomer in an aqueous medium in the presence of an emulsifier by a known method. The polymer component concentration in the polymer aqueous dispersion is 30 to 6
0% by weight is preferred.

Since the stain resistance is a performance greatly required for a water-resistant paint having weather resistance, the polymer used in the present invention is an acrylic polymer, an acrylic silicon polymer, a fluorine-containing polymer or the like. Aqueous dispersions of polymers having are preferred. Hereinafter, these polymers will be described.

Examples of the acrylic polymer include those in which (meth) acrylic acid ester is an essential component and other monomers are polymerized as necessary. In this case, as the (meth) acrylate, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylate
Examples include propyl acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, benzyl (meth) acrylate, and cyclohexyl (meth) acrylate. Other monomers include aromatic-containing monomers such as styrene, α-methylstyrene and vinyltoluene;
(Meth) acrylic acid, maleic acid, maleic anhydride, crotonic acid, itaconic acid, fumaric acid, citraconic acid and other carboxyl group-containing monomers, carboxylic anhydride-containing monomers and salts thereof; (meth) acrylic Amino group-containing monomers such as dimethylaminoethyl methacrylate, dimethylaminopropyl (meth) acrylate and diethylaminoethyl (meth) acrylate; (meth) acrylamides such as (meth) acrylamide, N, N-dimethylacrylamide and N-methylacrylamide ) Acrylamides; vinyl esters such as vinyl acetate, vinyl propionate and vinyl caproate; vinyl ethers such as ethyl vinyl ether, butyl vinyl ether and cyclohexyl vinyl ether;
Epoxy group-containing monomers such as glycidyl acrylate; hydroxyl-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl vinyl ether; trifluoro (meth) acrylate (Meth) acrylic esters having a fluorinated alkyl group such as methyl and pentafluoropentyl (meth) acrylate; vinylidene chloride, propylene and the like. Other than these, polyether poly (meth) acrylate [commercially available include Blenmer manufactured by NOF Corporation], polyester poly (meth) acrylate [commercially available Alonix and Toagosei Co., Ltd. And a macromonomer having a (meth) acryloyloxy group at a terminal [a commercially available product such as a macromonomer manufactured by Toagosei Co., Ltd.] can also be used.

As the acrylic silicone polymer, a monomer having an ethylenically unsaturated group and a hydrolyzable silyl group (hereinafter referred to as a hydrolyzable silyl group-containing monomer) in the above acrylic polymer is an essential component. And the like, and the like. In the monomer, the ethylenically unsaturated group includes (meth) acrylic group, vinyl group, vinyloxy group, allyl group and the like, and the hydrolyzable silyl group includes trimethylsilyl group, triethylsilyl group, methyltrimethylsilyl group. Examples include a methoxysilyl group and a methyltriethoxysilyl group. Specific examples of the hydrolyzable silyl group-containing monomer include trimethoxyvinylsilane, triethoxyvinylsilane, tripropoxyvinylsilane, methyldimethoxyvinylsilane, 3-trimethoxysilylpropyl (meth) acrylate, and 3-triethoxysilylpropyl (meth). ) Acrylate, 3-methyldimethoxypropyl (meth) acrylate, 3-methyldiethoxypropyl (meth) acrylate, 6-trimethoxysilyl-
Examples include 1-heptene and 6-triethoxysilyl-1-heptene. The copolymerization ratio of these hydrolyzable silyl group-containing monomers should be 1 to 20 mol% from the balance of the stability of the aqueous dispersion of the obtained polymer, the storage stability and the physical properties of the obtained coating film. Is preferred.

The fluorinated polymer is obtained by copolymerizing a fluoroolefin as an essential component and other monomers as required. Examples of the fluoroolefin include vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and chlorotrifluoroethylene. As the other monomer, those similar to those exemplified as the other monomer in the above-mentioned hydroxyl group-containing fluoropolymer can be used.

The aqueous dispersion of the polymer may be one obtained by emulsion polymerization using the above-mentioned monomers by a known method. As a polymerization method, batch polymerization, emulsion monomer addition polymerization, or the like can be employed. It is also possible to employ a polymerization method in which the composition of the added monomer is changed with time during polymerization, or a polymerization method in which the charged composition is changed so as to obtain a core / shell structure.

As the emulsifier to be used, a commonly used nonionic emulsifier and anionic emulsifier can be used. Examples of anionic emulsifiers include ammonium and potassium perfluorooctanoic acids and fluorinated anionic emulsifiers such as sodium perfluorooctanesulfonate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium alkylnaphthalenesulfonate, dialkyl Examples include hydrocarbon-based anionic emulsifiers such as sodium sulfosuccinate, sodium polyoxyethylene alkyl ether sulfate and sodium alkane sulfonate. Nonionic emulsifiers include polyoxyethylene alkyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester And hydrocarbon nonionic emulsifiers such as polyoxyethylene fatty acid esters, and fluorine nonionic emulsifiers such as perfluoroalkylethylene oxide adducts and monohydropolyfluoroalkylethylene oxide adducts. Also, a reactive emulsifier can be used. These emulsifiers may be used alone or in combination of two or more.

When a radical polymerization initiator is used,
Organic peroxides such as diisopropylperoxydicarbonate, tert-butylperoxypivalate, benzoyl peroxide, lauroyl peroxide and succinic acid peroxide, azobisisobutyronitrile, azobisisovaleronitrile and azobisamidino Azo compounds such as propane hydrochloride ammonium persulfate, and inorganic peroxides such as potassium persulfate can be used. When performing Redox polymerization, a reducing agent such as sodium bisulfite, Rongalit, and ascorbic acid may be used.

In the aqueous dispersion of the polymer, the T
When g is 10 ° C or less, a coating film can be formed at room temperature as it is, but when Tg is 10 ° C or more, an organic solvent should be blended as a film-forming aid. Is preferred. The amount of the organic solvent to be added depends on the storage stability of the aqueous coating composition to be obtained,
0.1 to 30 parts by weight per part by weight is preferred. As the organic solvent as the film-forming aid, those usually used in aqueous paints can be used. For example, straight-chain, branched or cyclic aliphatic alcohols having 5 to 10 carbon atoms, containing an aromatic group alcohols; formula HO- (CH ₂ CHXO) _n -R
(R: a linear or branched alkyl group having 1 to 10 carbon atoms,
X: hydrogen or a methyl group, an integer of n ≦ 5, monoethers such as (poly) ethylene glycol or (poly) propylene glycol; a general formula R ¹ COO— (CH ₂
CHXO) _n -R ² (R ¹ , R ² : linear or branched alkyl group having 1 to 10 carbon atoms, X: hydrogen or methyl group, n
(Integer of ≦ 5) (poly) ethylene glycol ether ester or (poly) propylene glycol ether ester; sorbites; and aromatic organic solvents such as toluene and xylene.

2-2. Production method of aqueous coating composition The aqueous coating composition of the present invention can be obtained by mixing a stain resistance imparting agent and an aqueous dispersion of a polymer according to a conventional method. The mixing ratio of the stain resistance imparting agent to the aqueous dispersion of the polymer is preferably 2 to 50 parts by weight of the solid content of the stain resistance imparting agent per 100 parts by weight of the polymer in the dispersion. If this value is less than 2 parts by weight, the stain resistance of the coating film of the obtained composition may not be exhibited, while if it exceeds 50 parts by weight, the stain resistance imparting agent and the aqueous dispersion of the polymer may not be obtained. In some cases, the resin component is precipitated and the pot life is shortened. When the aqueous dispersion of the polymer is blended with a film-forming auxiliary, it is preferable to add the aqueous dispersion to the aqueous dispersion in advance. As for the mixing of the aqueous dispersion of the polymer and the stain resistance imparting agent, it is preferable to add the partially hydrolyzed composition while stirring the aqueous dispersion of the polymer immediately before coating.

In the aqueous coating composition of the present invention, the gloss of the formed coating film may be insufficient depending on the type and amount of the stain resistance imparting agent. In this case, it can be prevented by adding a nonionic surfactant and using an emulsified agent as a stain resistance imparting agent. As the nonionic surfactant, the same ones as described above can be used. As a method of adding the nonionic surfactant, a method of adding a nonionic surfactant when mixing the aqueous dispersion of the polymer and the stain resistance imparting agent, or a method of adding the nonionic surfactant to the nonionic surfactant is used. A method in which the compound is previously blended in the stain imparting agent can be used. The addition amount of the nonionic surfactant is preferably used within a range that does not impair the water resistance of the obtained coating film, and the amount is 5 parts by weight or less per 100 parts by weight of the polymer in the aqueous dispersion of the polymer. It is preferred that When using an emulsified stain resistance imparting agent, a method for producing an emulsion of the stain resistance imparting agent uses a nonionic surfactant, an anionic surfactant or a surfactant in which both are used in combination. And emulsifying the stain resistance imparting agent in water. in this case,
The amount of the surfactant used is determined based on the stability of the emulsion of the stain resistance-imparting agent and the water resistance of the coating film of the aqueous coating composition finally obtained, based on 100 parts by weight of the active ingredient of the stain resistance-imparting agent. ,
It is preferably 0.5 to 30 parts by weight. As the types of these surfactants, those usually used in emulsification of a polymer may be used.

When an acrylic silicone polymer is used as the aqueous dispersion of the polymer, an organic titanate compound, an organic aluminum compound, an organic tin compound, a metal salt of a carboxylic acid, or the like can be added as a curing catalyst. .

The aqueous coating composition of the present invention may contain a pigment, an antifoaming agent, a thickener, an antifungal agent, an antiseptic, an antibacterial agent, an ultraviolet absorber, a light stabilizer, a leveling agent, a slip agent, if necessary. Additives that are commonly used in aqueous paints, such as anti-sag agents, anti-separation agents, antioxidants and heat stabilizers, may be added.
When the pigment is dispersed in the composition, a pigment dispersant may be added. These can be previously blended in the aqueous dispersion of the polymer.

The application of the aqueous coating composition of the present invention may be carried out in accordance with a method generally used for aqueous coatings, for example, by spray coating, brushing or the like. In this case, the thickness of the paint may be selected according to the purpose.
It is preferably from 50 μm to 50 μm.

[0045]

The present invention will now be described more specifically with reference to examples and comparative examples. In the following,% means weight%.
Means

Example 1-1 Synthesis of Stain Resistance-Proof Agent As a hydroxyl group-containing acrylic polymer, methyl methacrylate / butyl methacrylate / 2-hydroxyethyl methacrylate = 29/58/13 (mol%) The polymer (A-1) having a number average molecular weight of 8000 was used. 50 g of a 50% xylene solution of A-1 and tetraethoxysilane 260
g, propylene glycol monomethyl ether 150
g, 150 g of isopropanol and 0.6 g of p-toluenesulfonic acid in a 1-liter three-necked flask,
The temperature was raised to 60 ° C. in a nitrogen stream. Next, ion-exchanged water 2
A mixture of 2.5 g and 22.5 g of isopropanol was added to 30
The mixture was added dropwise over a period of 1 minute, and further stirred at 60 ° C. for 1 hour to conduct a condensation reaction. The obtained reaction solution is neutralized by passing through a basic ion exchange resin, and then concentrated under reduced pressure to 60 g at 60 ° C. using an evaporator, and then isoprene glycol monoethyl ether [Solfit, Inc.]
100 g of Kuraray). The obtained stain resistance imparting agent (S-1) is a polymer / SiO ₂ = 100/290 [weight ratio (calculated value)], takes about 2 g of the stain resistance imparting agent, and is heated at 220 ° C. for 10 minutes. The residual ratio when evaporated to dryness, that is, the solid content was 44%. The amount of ethanol as a primary alcohol having 4 or less carbon atoms in the solution was 0.5% by gas chromatography.

Example 1-2 Synthesis of Stain Resistance-Proofing Agent 50 g of a 50% xylene solution of A-1; 25 g of polyethylene glycol (PEG1000, manufactured by NOF Corporation, number average molecular weight 1000); tetraethoxysilane 350
g, propylene glycol monomethyl ether 180
g, 150 g of Solfit and 0.6 g of p-toluenesulfonic acid were charged into a 1-liter three-necked flask, and heated to 60 ° C. in a nitrogen stream. Next, 30. ion-exchanged water.
A mixture of 3 g and 30.3 g of isopropanol was added dropwise over 30 minutes, and the mixture was further stirred at 60 ° C. for 1 hour to perform a condensation reaction. The obtained reaction solution was neutralized and concentrated to 420 g in the same manner as in Example 1-1, and 150 g of Solfit was added thereto. The obtained stain resistance imparting agent (S-2)
Is (total amount of polymer and PEG 1000) / SiO ₂ =
100/200 [weight ratio (calculated value)], solid content 48%,
Ethanol was 0.3%.

Comparative Example 1-1 40 g of ethanol was added to the stain resistance imparting agent S-1 obtained in Example 1-1 to obtain a solution having an ethanol content of 9.5% (S-3, Solids 40%).

Comparative Example 1-2 30 g of a 50% xylene solution of A-1, 600 g of tetraethoxysilane, 250 g of propylene glycol monomethyl ether, 250 g of isopropanol and 0.6 g of p-toluenesulfonic acid were placed in a 2 liter three-necked flask. It was charged and heated to 60 ° C. in a nitrogen stream. Next, a mixture of 62.3 g of ion-exchanged water and 62.3 g of isopropanol was added dropwise over 30 minutes, and the mixture was further stirred at 60 ° C. for 1 hour to perform a condensation reaction. The obtained reaction solution was prepared in Example 1
Neutralization / concentration was performed in the same manner as in Example 1 to 700 g, and 100 g of Solfit was added. The obtained stain resistance imparting agent (S-4) is a polymer / SiO ₂ = 100/1120
[Weight ratio (calculated value)] Under the same conditions as in Synthesis Example 1, the solid content was 45%, and the amount of ethanol was 2.7%.

Synthesis Example 1 Aqueous dispersion of fluorine-containing polymer Zaflon EM-60 which is a fluorine-containing polymer emulsion
00 [copolymer with chlorotrifluoroethane, vinyl ester and other monomers, manufactured by Toagosei Co., Ltd., solid content 50%, F-1] 100.0 g, a film-forming auxiliary [2, 2,
4-trimethyl-1,3-pentanediol monoisobutyrate, Texanol CS12, Chisso Corporation] 5.
0 g and a thickener [SN thickener-612, San Nopco Co., Ltd.] 1.2 g were mixed with stirring, and an aqueous dispersion of a fluoropolymer as a clear paint (T-1, resin content 47%)
Was adjusted.

Synthesis Example 2 Preparation of Aqueous Dispersion of Acrylic Polymer Polytron F220 which is an acrylic polymer emulsion
0 [manufactured by Asahi Kasei Corporation, solid content 50%, A-2]
0 g, 2.5 g of a film-forming auxiliary (Texanol CS12) and a thickener [Adecanol UH-420, Asahi Denka Co., Ltd.]
An aqueous dispersion (T-2, resin content: 48.5%) of the clear coating acrylic polymer was prepared by mixing 0.5 g of the mixture with stirring.

Synthesis Example 3 Preparation of aqueous dispersion of fluoropolymer Titanium oxide [CR97, manufactured by Ishihara Sangyo Co., Ltd.] 100.0
g, a pigment dispersant [SN Dispersant 5027, manufactured by San Nopco Co., Ltd.] 5.0 g, an antifoaming agent [FS Antifoam 0
13B, Dow Corning Co., Ltd.] and 0.5 g of ion-exchanged water were dispersed with a homodisper to disperse the pigment. 300.0 g of F-1 as a fluorine-containing copolymer emulsion, 18.0 g of a film-forming aid (Texanol CS12) and 1.2 g of a thickener (SN thickener 612) were mixed with the above pigment dispersion under stirring. The liquid was added to prepare an aqueous dispersion of a fluoropolymer as a white paint (T-3, resin content: 31.7%).

Examples 2-1 to 2-5 20% of the stain resistance imparting agent, the aqueous polymer dispersion and the emulgen 930 (manufactured by Kao Corporation) as a nonionic surfactant in the proportions shown in Table 1. The aqueous solution was mixed with stirring to prepare an aqueous coating composition. The following test was performed about the obtained composition.

Pot life After mixing the stain resistance-imparting agent and the aqueous dispersion of the polymer, the time until gelation was measured.

Gloss value On a 5052P aluminum substrate, ureol 800, which is an acrylic urethane paint manufactured by Kawakami Paint Co., Ltd., was applied. The resulting composition was applied on the coating using a bar coater (dry film thickness: about 30 μm), dried at room temperature for one week, and measured for 60 ° gloss.

Stain resistance The obtained coating film was subjected to an exposure test at an angle of 45 degrees for 5 months in an industrial zone in the southern part of Nagoya City, and ΔL as a change in L value before and after the test was determined. The smaller the absolute value of ΔL, the better the stain resistance. Table 2 shows the results.

[0057]

[Table 1]

[0058]

[Table 2]

Comparative Examples 2-1 to 2-5 A stain resistance-imparting agent, an aqueous polymer dispersion and a 20% aqueous solution of Emulgen 930 were mixed with stirring at the ratios shown in Table 3 in the same manner as in the Examples. , An aqueous coating composition was prepared. The obtained composition was subjected to the same test as in the above example. Table 4 shows the results.

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

According to the stain resistance imparting agent for water-based paints of the present invention, the pot life after mixing the stain resistance imparting agent and the aqueous dispersion of the polymer is long, and the stain resistance imparting agent is improved. The aqueous coating composition containing is excellent in stain resistance of the coating film.

Claims (2)

[Claims] A hydrophilic organic solvent solution containing a hydroxyl group-containing polymer or the hydroxyl group-containing polymer, a polyalkylene glycol, an alkoxysilane having two or more alkoxy groups having 2 to 4 carbon atoms, and water is prepared in an acidic atmosphere. The solution obtained by heating under the above, the content of Si derived from the alkoxysilane, the total amount of solids derived from the hydroxyl group-containing polymer or the hydroxyl group-containing polymer and the polyalkylene glycol 100 wt. To 50 parts by weight in terms of SiO ₂ , and 0 to 5% by weight of a primary alcohol having 4 or less carbon atoms. 2. An aqueous coating composition containing the stain resistance imparting agent for aqueous coating composition according to claim 1.