JP2002180011A - Water-borne coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water-borne coating composition capable of forming a film having excellent hot water, weather and alkali resistances, etc. SOLUTION: This water-borne coating composition comprises the following components. (I) an aqueous resin having hydrolyzable silyl groups in the molecule and (II) a cagelike ammonium silicate compound obtained by reacting (a) 0.5-1.5 mol of an organosilane compound comprising an organoslilane represented by formula (1): Si(OR1)4 [wherein, R1 is a 1-5C alkyl group] and an organosilane represented by formula (2): R2Si(OR3)3 [wherein, R2 is a 1-8C organic group; and R3 is a 1-5C alkyl group] in [(0.3-1.0):(0.7-0)] molar ratio of both with (b) 1.0 mol of a quaternary ammonium compound in the presence of water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous coating composition capable of forming a coating film having excellent hot water resistance, weather resistance, stain resistance, solvent resistance, alkali resistance and the like.

[0002]

2. Description of the Related Art A coating film comprising, as a binder, a mixture of an organic-inorganic composite resin and a curing agent obtained by subjecting an organosilane and / or a partially hydrolyzed condensate thereof to a hydrolysis-condensation reaction of a silyl group-containing vinyl resin is used. Excellent in weather resistance, stain resistance, etc.,
Also, as compared with a coating film using an organopolysiloxane-based inorganic resin as a binder, cracks are less likely to occur, and therefore, a paint composition using a mixture of the above-mentioned organic-inorganic composite resin and a curing agent as a binder has attracted attention. It is becoming. However, many of such coating compositions are organic solvent-based coatings using an organic solvent as a solvent, which is not preferable from the viewpoint of air pollution and resource saving. Accordingly, water-based paints using a mixture of an organic-inorganic composite resin and a curing agent as a binder have been developed, but the resulting coating film has a problem in that hot water resistance and alkali resistance are poor.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems in the prior art, and is directed to an aqueous resin having a hydrolyzable silyl group and a curing agent comprising a cornified ammonium silicate compound. It is an object of the present invention to provide an aqueous coating composition capable of forming a coating film having excellent hot water resistance, alkali resistance, weather resistance, stain resistance, and the like by using the same.

[0004]

That is, the present invention provides the following invention, (I) an aqueous resin having a hydrolyzable silyl group in a molecule, and (II) (a) a compound represented by the formula (1), Si (OR) ¹ ) _{4 wherein} R ¹ is an alkyl group having 1 to 5 carbon atoms. And an organosilane represented by the formula (2): R ² Si (OR ³ )
₃ [wherein R ² is an organic group having 1 to 8 carbon atoms;
³ is an alkyl group having 1 to 5 carbon atoms. And an organosilane represented by the formula:
0.5 to 1.5 mol of an organosilane compound ([0.3 to 1.0) :( 0.7 to 0)] and 1.0 mol of a (b) quaternary ammonium compound are combined with water. A cage-like ammonium silicate compound obtained by reacting in the presence of an aqueous solution.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (I) Component The component (I) of the coating composition of the present invention is an aqueous resin having a hydrolyzable silyl group in the molecule and being dissolved or stably dispersed in water. As long as the resin has such characteristics, various known organopolysiloxane-based inorganic resins and vinyl resins, or organic-inorganic composite resins or mixed resins that are the reactants of these resins can be used without particular limitation. It is possible. Particularly, in the present invention, the resin (A) and the resin (B) described below are preferable.

[0006] Resin (A) The resin (A), (c) Equation _{^{(3), R 4 n Si}} (OR 5) 4-n wherein, R ⁴ is an organic group having 1 to 8 carbon atoms , R ⁵ is
It is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2. And (d) (i) a polymerizable unsaturated group having a polymerizable unsaturated group and a hydrolyzable group directly bonded to a silicon atom in the molecule. 1 to 50% by mass of a monomer;
(i) polymerizable unsaturated monomer other than the component 99 to 50% by mass
And 10 to 2000 parts by mass of a monomer component consisting of
1, an aqueous resin obtained by emulsion polymerization in water in the presence of a condensation reaction accelerator such as a Ti or Zr-based metal chelate compound.

In the above formula (3), examples of the organic group as R ⁴ include an alkyl group, a cycloalkyl group and an aryl group. Here, the alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and s.
-Butyl group, t-butyl group, pentyl group, hexyl group,
Examples include an alkyl group such as a heptyl group and an octyl group.
Preferred alkyl groups have 1 to 4 carbon atoms. Preferred examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Examples of the aryl group include a phenyl group.

Each of the above functional groups may optionally have a substituent. Examples of such a substituent include a halogen atom (for example, a chlorine atom, a bromine atom, a fluorine atom, etc.)
And (meth) acryloyl group, mercapto group, alicyclic group and the like. The alkyl group as R ⁵ may be linear or branched. Examples of such an alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and s.
-Butyl group, t-butyl group, pentyl group and the like,
Preferred alkyl groups have 1 to 2 carbon atoms.

Specific examples of the organosilane represented by the above formula (3) include, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, and n-propyltrimethoxysilane. -Propyltriethoxysilane, i-
Propyltrimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ
-Chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-
Trifluoropropyltriethoxysilane, cyclohexyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, phenyltrimethoxysilane ,

Phenyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane,
Methylphenyldimethoxysilane, dimethyldipropoxysilane and the like can be mentioned, and preferred are methyltrimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane and dimethyldimethoxysilane.

The component (c) comprises one of these organosilanes.
Species alone, or a mixture of two or more, or
These are partially hydrolyzed condensates obtained by subjecting these to hydrolysis and condensation reactions. The molecular weight of the partially hydrolyzed condensate is a weight average molecular weight in terms of polystyrene, for example, 300 to 500.
0, preferably 500 to 3000, and by using a condensate having such a molecular weight, a coating film having good adhesion can be obtained without deteriorating polymerization stability and storage stability. Furthermore, partial hydrolysis condensate of organosilane, a -OH group or -OR ⁵ group bonded to the silicon atom, for example, 1 or more, and preferably those having 3 to 30.

Specific examples of such a condensate include commercially available products such as SH6018 manufactured by Dow Corning Toray Co., Ltd.,
DC6-2230, SR2402, DC3037, DC
3074; KR-211 manufactured by Shin-Etsu Chemical Co., Ltd., KR-
212, KR-213, KR-214, KR-215,
KR-216, KR-218; T made by Toshiba Silicone Co., Ltd.
SR-145, TSR-160, TSR-165, Y
R-3187 and the like. In the present invention, (c)
Component has the formula, -OR ⁵ (R ⁵ is an alkyl group having 1 to 5 carbon atoms.) Hydrolyzable groups directly attached to a silicon atom, all hydrolyzed, -O
It is particularly preferable to use a partially hydrolyzed condensate containing only H, because the production of alcohols as volatile organic compounds is reduced during the emulsion polymerization and the emulsion polymerization can be stably completed.

The organosilane which has not been condensed with the partially hydrolyzed condensate of the organosilane represented by the above formula (3) is 1 to 30 parts by mass, preferably 1 to 30 parts by mass, per 100 parts by mass of the former. When 10 parts by mass are used in combination, the component (c) and the component (d) described later tend to undergo a grafting reaction efficiently during emulsion polymerization, and the hardness of the coating film obtained is adjusted by the ratio of both components. It is desirable because it becomes possible. The component (d) is a polymerizable unsaturated monomer component composed of the components (i) and (ii) described below.

[0014] The component (i) is subjected to emulsion polymerization to form the component (ii) described below.
A condensation reaction with a polymerizable unsaturated group for forming a vinyl copolymer with the component and the organosilane represented by the above formula (3) and / or a partially hydrolyzed condensate thereof is carried out. It is a polymerizable unsaturated monomer having a hydrolyzable group directly bonded to a silicon atom for grafting to a polymer. Specific examples of such a polymerizable unsaturated monomer include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, β- (meth) acryloxyethyltrimethoxysilane, β- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (Meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropylmethyldipropoxysilane,
Examples include γ- (meth) acryloxybutylphenyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropyldiethylmethoxysilane, and the like.

The component (ii) is a component which forms a vinyl copolymer by radical polymerization with the component (i), and various polymerizable polymers conventionally used in the production of vinyl copolymers. Saturated monomers can be used. Specifically, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic acid (Meth) acrylic acid ester monomers such as stearyl and cyclohexyl (meth) acrylate; (meth) acrylic acid, crotonic acid, itaconic acid, itaconic acid half ester,

Maleic acid, maleic acid half ester,
Carboxyl group-containing monomers such as maleic anhydride and fumaric acid or anhydrides thereof; hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, hydroxybutyl (meth) acrylate, monohydric alcohols ( Hydroxyl-containing monomers such as (meth) acrylates; epoxy-containing monomers such as glycidyl (meth) acrylate and allyl glycidyl ether; styrene-based monomers such as styrene, methylstyrene, and methoxystyrene; Examples include methylol acrylamide, vinyl acetate, vinyl propionate, vinyl chloride, (meth) acrylonitrile, and the like.

The component (d) comprises the components (i) and (ii) described above.
Components, and the compounding mass ratio of both is (1 to 5
0): (99-50), preferably (1.5-30):
(98.5 to 70), and the amount of the component (d) is suitably from 10 to 2,000 parts by mass, preferably from 50 to 1,000 parts by mass, per 100 parts by mass of the component (c).

In the ratio of component (i) to component (ii), (i)
If the component is more than the above range, the appearance and crack resistance of the obtained coating film tend to be deteriorated, and if it is too small, the storage stability of the coating material and the hot water resistance and resistance of the obtained coating film are reduced. Alkalinity and the like tend to decrease. On the other hand, if the amount of the component (d) is too large, the weather resistance and stain resistance of the resulting coating film tend to decrease. Conversely, if the amount is too small, the resistance of the resulting coating film tends to decrease. Cracking properties, alkali resistance, and the like tend to decrease. As the condensation reaction accelerator,
Although various known accelerators can be used, in particular, Al, T
The i or Zr-based metal chelate compound is formed by the above-mentioned component (c) of the organosilane and / or its partially hydrolyzed condensate and the aforementioned component (i) of the polymerizable unsaturated monomer in the polymerizable unsaturated monomer. In addition to accelerating the condensation reaction, the component (c) is grafted to the vinyl copolymer formed from the components (i) and (ii), and the resulting coating film has a hot water resistance, an alkali resistance and the like. It is preferable to improve

As the Al, Ti or Zr-based metal chelate compounds, those conventionally used for condensing organosilanes can be used as they are.
Specifically, for example, zirconium chelate compounds such as tetraacetyl acetate zirconium, tetraethyl acetoacetate zirconium, tri-n-butoxyethyl acetoacetate zirconium, and di-n-butoxydi (ethylacetoacetate) zirconium; diisopropoxybis ( Acetyl acetate) titanium,
Titanium chelate compounds such as diisopropoxybis (ethylacetoacetate) titanium; organometallic compounds such as aluminum chelate compounds such as monoacetylacetatebis (ethylacetoacetate) aluminum, diisopropoxyethylacetoacetatealuminum, and trisacetylacetatealuminum Is mentioned.

The compounding amount of the Al, Ti or Zr-based metal chelate compound is, for example, based on 100 parts by mass of the component (c).
0.3 to 10 parts by mass, preferably 0.5 to 5 parts by mass is suitable. In the method for producing the resin (A), for example, the above-mentioned component (c) and the component (d) are stirred and mixed until a uniform solution is obtained, and the above-mentioned metal chelate compound is further mixed therein. Prepare. Next, the solution is stirred in water in the presence of an emulsifier, and after pre-emulsification or without pre-emulsification, in water, an emulsifier, a polymerization initiator, and, if necessary, a chain transfer agent or In the presence of an emulsion stabilizer or the like, usually at a temperature of 60 to 90 ° C, 2
Resin (A) by emulsion polymerization reaction for 10 to 10 hours,
That is, an aqueous dispersion of the aqueous organic-inorganic composite resin is produced.

As the above-mentioned emulsifier, various types of conventionally known anionic, cationic and nonionic surfactants and reactive emulsifiers having a radically polymerizable functional group can be appropriately used. Specifically, for example, sulfuric acid ester salts of higher alcohols, polyoxyethylene alkyl sulfate salts, alkylbenzene sulfone salts, polyoxypropylene alkyl sulfate salts, polyoxyethylene alkylphenol ether sulfate salts, polyoxypropylene alkylphenol ether sulfate salts and the like Anionic surfactants; cationic surfactants such as alkyltrimethylammonium chloride and alkylbenzylammonium chloride; polyoxyethylene alkyl ethers;

A polyoxypropylene alkyl ether,
Polyoxyethylene alkylphenol ether, polyoxypropylene alkylphenol ether, ethylene oxide propylene oxide block polymer,
Nonionic surfactants such as sorbitan derivatives; and reactive emulsifiers such as trimethylolpropane acrylate and alkenyl succinate monoallyl ester salts. Further, as the polymerization initiator, for example, ammonium persulfate, potassium persulfate, hydrogen peroxide, t-
Water-soluble polymerization initiators such as butyl hydroperoxide;
Oil-soluble polymerizable initiators such as azoisobutyronitrile, benzoyl peroxide and cumylperoxy octoate; and redox type using a reducing agent such as Rongalit and ascorbic acid in combination.

Examples of the chain transfer agent include, for example, n-
Examples thereof include long-chain alkyl mercaptans such as dodecyl mercaptan, aromatic mercaptans, and halogenated hydrocarbons. In addition, as an emulsion stabilizer,
Polyvinyl alcohol, hydroxyethyl cellulose, polyvinyl pyrrolidone and the like can be mentioned. As an emulsion polymerization method for producing an aqueous dispersion of an aqueous organic-inorganic composite resin, a batch charging method has been exemplified. However, the above-mentioned solution or a dropping method in which the pre-emulsified liquid is continuously dropped into water while emulsion polymerization is performed. The aforementioned solution or
A seed polymerization method in which a part of the pre-emulsified liquid is subjected to emulsion polymerization in water, and then the remaining part is added dropwise to carry out emulsion polymerization; further, the composition of the polymerizable unsaturated monomer, which is the component (d) of the core-shell, was changed. A core / shell polymerization method or the like can be appropriately adopted.

The aqueous dispersion of the aqueous organic-inorganic composite resin thus obtained may be used in order to improve the freeze-thaw stability and the storage stability by using ammonia, amines such as trimethylamine, triethylamine and dimethylethanolamine. It is preferable that the pH is adjusted to 6 to 9 by the above-mentioned methods. Resin (B) The resin (B) was bonded to (e) 100 parts by mass of the organosilane represented by the above formula (3) and / or its partially hydrolyzed condensate, and (f) a hydrolyzable silyl group or a hydroxyl group. It has a silyl group having a silicon atom, and has an acid value of 20 to 1.
50 mg KOH / g silyl group-containing vinyl resin 5-2
This is an aqueous resin obtained by neutralizing a hydrolysis-condensation reaction product with 00 parts by mass with a neutralizing agent. The component (e) is the same as the component (c) described above.

The component (f) contains at least one silyl group having a silicon atom bonded to a hydrolyzable silyl group or a hydroxyl group at the terminal or side chain of the vinyl resin in one molecule of the resin.
, Preferably two or more, and an acid value of 20 to 15
0 mgKOH / g, preferably a vinyl resin having a molecular weight of, for example, about 1,000 to 50,000. The silyl groups of the formula _{(4), -SiX P (R} 6) (3-P) wherein, X is, or alkoxy group, an acyloxy group, a halogen group, a ketoximate group, a mercapto group, an alkenyloxy group, phenoxy R ⁶ is hydrogen or a monovalent hydrocarbon group such as an alkyl group having 1 to 10 carbon atoms, an aryl group, an aralkyl group,
P is an integer of 1 to 3. ].

The vinyl resin having a silyl group is, for example, a compound represented by the formula (5), (X) _P (R ⁶ ) _{(3 - P)} Si—H wherein X, R ⁶ and P are represented by the above formula (4) ) Has the same meaning as ] And a vinyl resin having a carbon-carbon double bond according to a conventional method. In addition, as the hydrosilane compound, for example, methyldichlorohydrosilane, methyldiethoxyhydrosilane, methyldiacetoxyhydrosilane, and the like are typical examples. The amount of the hydrosilane compound used is suitably, for example, 0.5 to 2 times the molar amount of the carbon-carbon double bond contained in the vinyl resin.

The vinyl resin contains (meth) acrylic acid, a carboxylic acid such as itaconic acid and fumaric acid, or an acid anhydride such as maleic anhydride as an essential vinyl monomer, and further comprises methyl (meth) acrylate. And (meth) acrylates such as ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) acrylic acid; 2-hydroxyethyl (meth) acrylate, 2 -Hydroxy group-containing vinyl monomers such as -hydroxypropyl (meth) acrylate and 2-hydroxyvinyl ether; copolymers with other vinyl monomers selected from the group consisting of acrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, etc. Are preferred, and (meth) acrylic By radical copolymerization of allyl or diallyl phthalate, carbon in order to hydrosilylation reaction in the vinyl resin - allows the introduction of carbon double bonds.

The above-mentioned carboxylic acid or acid anhydride is
In the constituent monomers of the copolymer, the acid value of the obtained vinyl resin is 20 to 150 mgKOH / g, preferably 50 to 50 mgKOH / g.
It is preferred that the content be contained so as to be 120 mgKOH / g. When the acid value is smaller than the above range, the storage stability of the obtained paint tends to decrease, and when it is larger, the water resistance, hot water resistance and the like of the obtained coating film tend to decrease. Further, as the other method for producing the silyl group-containing vinyl resin, a vinyl monomer containing the carboxylic acid or acid anhydride and a silyl group-containing vinyl compound composed of the component (i) are contained as essential monomers. Further, there is a method in which one or more of the above-mentioned other vinyl monomers are subjected to radical polymerization, if necessary.

Specific examples of these silyl group-containing vinyl resins include commercially available products such as Kanekazemurakku manufactured by Kanegafuchi Chemical Industry Co., Ltd. As the neutralizer, various nitrogen-containing basic compounds conventionally known as neutralizers can be used without particular limitation. Specifically, for example, trimethylamine, triethylamine, alkylamines such as tributylamine, triethanolamine, dimethylethanolamine, diethanolamine, monoethanolamine,
Representative examples include alcohol amines such as N-methyldiethanolamine, N, N-dimethylethanolamine and ethylpropanolamine, and volatile nitrogen-containing basic compounds such as morpholine and ammonia.

Further, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-
(Β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldiethoxysilane, N
-Cyclohexyl-γ-aminopropyltrimethoxysilane, N-cyclohexyl-γ-aminopropyltriethoxysilane, γ- (2-aminoethyl) -aminopropyltrimethoxysilane, γ- (2-aminoethyl)-
Amino group-containing alkoxysilanes such as aminopropylmethyldimethoxysilane and γ-anilinopropyltrimethoxysilane can also be used as a part of the neutralizing agent.

In the method for producing the resin (B), for example, a mixture of the above-mentioned components (e) and (f) is subjected to a hydrolytic condensation reaction in the presence of water and a catalyst. The mixing ratio of the component (e) to the component (f) is 5 parts per 100 parts by mass of the former.
It is suitably from 200 to 200 parts by mass, preferably from 10 to 150 parts by mass. Incidentally, if the latter is less than the above range, the appearance and crack resistance of the obtained coating film, frost damage resistance, alkali resistance and the like tend to decrease, and conversely, if too large,
The weather resistance, stain resistance and the like of the obtained coating film tend to decrease. The amount of water is 45 to 100 of the hydrolyzable group initially present in the mixture of the component (e) and the component (f).
%, Preferably 50 to 90%, which is sufficient to hydrolyze, specifically 0.4 to 1.0 times the total number of hydrolysable groups in the mixture, preferably 0.5 to 90%. It is appropriate that the amount is 0.9 times the number of moles.

Examples of the catalyst include inorganic acids such as nitric acid and hydrochloric acid, and organic acids such as acetic acid, formic acid and propionic acid. The amount of the catalyst added is such that the pH of the mixture is 3
An amount of up to 6 is appropriate. The hydrolysis condensation reaction is
Mixing the mixture of component (e) with component (f) in the presence of water and a catalyst at 40-80 ° C, preferably 45-65 ° C;
A method of reacting while stirring for 2 to 10 hours is suitable. The amount of water is set to 45% or more of the hydrolyzable group initially present in the mixture of the component (e) and the component (f) with the resin (B), that is, the organic-inorganic composite resin. When it becomes an aqueous dispersion (emulsion), storage stability is good,
This is because a highly transparent film can be formed.

Although the hydrolysis-condensation reaction between the component (e) and the component (f) can be carried out in one step as described above, from the viewpoint of storage stability of the product, More preferably, the reaction is performed in two steps. That is, as a first step, in the presence of water and an acid catalyst, 40-80%, preferably 45%, of the hydrolyzable groups initially present in the mixture of component (e) and component (f). 40 to 80 ° C., preferably so that about 70% undergoes a hydrolytic condensation reaction.
The reaction is carried out at 45 to 65 ° C. for 1 to 8 hours with stirring.

As a second step, after the first step, water and a trialkoxy borane such as trimethoxy borane or triethoxy borane or the above-mentioned metal chelate compound are further added, and a hydrolysis condensation reaction is carried out. The amount of water added in the second stage is such that 45-100%, preferably 50-90% of the hydrolyzable groups initially present in the mixture of component (f) and component (g) are hydrolyzed. It is an amount sufficient for decomposition and condensation reactions. The trialkoxy borane or metal chelate compound used in the second step can accelerate the condensation reaction and improve the appearance, weather resistance, stain resistance, hot water resistance and the like of the coating film. These catalysts are used in an amount of 0.001 to 5 parts by mass based on 100 parts by mass of the total of the components (e) and (f) remaining unreacted with the reactant obtained in the first stage. Preferably, 0.005 to 2 parts by mass is appropriate.
The hydrolysis-condensation reaction in the second step is suitably carried out at 40 to 80 ° C. for 2 to 5 hours as in the first step.

The hydrolysis-condensation reaction product is in a solution state by the alcohol generated by the reaction, or by the alcohol and an organic solvent to be described later added as necessary. To the solution of the organic-inorganic composite resin thus obtained, add a neutralizing agent, uniformly disperse and neutralize, and then add water or simultaneously add the neutralizing agent and water and stir. To obtain an aqueous dispersion (emulsion) of the resin (B).

Component (II) The component (II) of the coating composition of the present invention is a cage-like ammonium silicate compound serving as a curing agent for the component (I).
The compound is represented by the formula (a): Si (OR ¹ ) ₄ [wherein:
R ¹ is an alkyl group having 1 to 5 carbon atoms. And an organosilane represented by the formula (2): R ² Si (OR ³ )
₃ [wherein R ² is an organic group having 1 to 8 carbon atoms;
³ is an alkyl group having 1 to 5 carbon atoms. The organosilane represented by the formula, and the molar ratio of both,
[(0.3 to 1.0): (0.7 to 0)], preferably, [(0.8 to 1.0): an organosilane compound of (0.2 to 0) 0.5 to 1.5 mol, preferably
It is obtained by reacting 0.8 to 1.1 mol with 1.0 mol of the (b) quaternary ammonium compound in the presence of water. If the ratio of the component (a) to the component (b) exceeds the above range, the unreacted remaining component (a) adversely affects the curability and stain resistance of the resulting coating film. When the latter is excessive, the unreacted remaining component (b) tends to adversely affect the storage stability of the paint.

In the above formula (1), examples of the alkyl group for R ¹ include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group,
Examples thereof include an S-butyl group, a t-butyl group, and a pentyl group. Preferred alkyl groups have 1 to 2 carbon atoms. Specific examples of the organosilane represented by the above formula (1) include, for example, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. The organosilane of the above formula (2) is obtained by converting n of the organosilane represented by the above formula (3).
This is the same as when the value is 1.

Further, quaternary ammonium compound which is component (b), the formula _{^{(6), NR 7 3 R}} 8 OH wherein, R ⁷ is an alkyl group having 1 to 8 carbon atoms, R ⁸ is , Carbon number 1-8
Is an organic group. ] The compound shown by these. R in the formula
The alkyl group of ⁷ may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group,
Examples thereof include an i-butyl group, an s-butyl group, a t-butyl group, a pentyl group, a hexyl group, and an octyl group. Preferred alkyl groups have 1 to 2 carbon atoms. Examples of the organic group for R ⁸ include an alkyl group, a cycloalkyl group, and an aryl group. Here, the alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group,
Examples thereof include alkyl groups such as s-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, octyl group and the like. Preferred alkyl groups have 1 to 4 carbon atoms.

Examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group and a cyclooctyl group. Examples of the aryl group include a phenyl group. Specific examples of such a quaternary ammonium compound include tetramethylammonium hydroxide, benzyltrimethylammonium hydroxide, and trimethylethylammonium hydroxide. The cage compound of the component (ii) is, for example, based on 1.0 mole of the component (b),
Component (a) is 0.5 to 1.5 moles, preferably 0.8 to 1.5 moles.
1.1 mol, water is 4.0 mol or more, preferably 5.0 to
It is manufactured by reacting a solution in which 10.0 mol is mixed while stirring at a temperature of 10 to 30 ° C. for 5 to 10 hours. The structure of the cage compound is represented by, for example, the formula (1)
The components obtained from the components (a) and (b) consisting only of the organosilane represented by the formula (1) are those represented by the formula (7).

Equation (7)

Embedded image[In the formula (7), X is NR⁷ _ThreeR⁸And R⁷And R
⁸Is the same as that of the above formula (6). Further, an organosilane compound represented by the formula (2)
The reaction in which the organosilane is used together has the formula
(7) [≡SiO^-X⁺] Is part of [≡SiR ^Two]
In the structure. Component (I) molecule
An aqueous resin having a hydrolyzable silyl group therein, and a component (II)
Mixing with basket-like ammonium silicate compound
And the hydrolyzable silyl group in component (I) and the component (II)
≡Si-O^-To form a cross-linked network
Then, the coating is cured.

The mixing ratio of the component (I) and the component (II) is such that the molar ratio of the hydrolyzable silyl group in the component (I) to ≡SiO ^- X ⁺ in the component (II) is (1: 0.5-1.5),
Preferably, (1: 0.7 to 1.3) is appropriate. The aqueous coating composition of the present invention is the main component described above.
The aqueous dispersion of the component (I) and the component (II) serving as a curing agent as the main components, and further, if necessary, dilution water for improving the storage stability and coating workability of the paint, It is composed of a mixture of an organic solvent, a filler, a dye, and various additives such as a thickener and a pigment dispersant.

Examples of the organic solvent include alcohols such as methanol, ethanol, propanol and butanol, alcohol ethers such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether, and ketones such as acetone and methyl ethyl ketone. It is possible to use a solvent or a mixed organic solvent thereof with various hydrophobic organic solvents for coating such as toluene, xylene, ethyl acetate and butyl acetate. These organic solvents can be previously blended with either component (I) or component (II). The amount of the organic solvent is 0 to 20% by mass, preferably 0 to 10% by mass in the coating composition.
Is appropriate.

As the filler, extenders and coloring pigments for various coatings such as talc, barium carbonate, calcium carbonate, bentonite, titanium oxide, carbon black, red iron, lithopone and the like can be used. The amount of the filler is suitably from 0 to 70% by mass, and preferably from 0 to 50% by mass, based on the solid content of the coating composition. The coating composition of the present invention is applied to the surface of the object to be coated by a coating means such as brush, spray, roller, dipping, etc.
It is possible to form a cured coating film by baking at a temperature of not more than ℃. Examples of the substrate include inorganic ceramic substrates, various metal substrates such as stainless steel and aluminum, glass substrates, plastic substrates, and paper substrates.

[0044]

The present invention will be described in more detail with reference to the following examples. In the examples, “parts” and “%” are shown on a mass basis unless otherwise specified. <Preparation of Aqueous Resin Dispersion A> In a glass beaker, a partially hydrolyzed condensate of phenyltrialkoxysilane and methyltrialkylalkoxysilane [“DC6-223”
0 "(manufactured by Dow Corning Toray Co., Ltd .; solid content 100)
%)], 0.5 part of γ-methacryloxypropyltrimethoxysilane, 15 parts of methyl methacrylate,
A monomer mixture consisting of 9 parts of n-butyl acrylate and 0.5 part of methacrylic acid was charged and stirred until a uniform solution was obtained. After homogenous mixing, 0.1 part of triacetylacetate aluminum, 1.0 part of methyltrimethoxysilane and 1.0 part of dimethyldimethoxysilane are added and mixed. -1025N "(manufactured by Asahi Denka Kogyo KK)] 0.75
And a mixture of 18 parts of ion-exchanged water and stirring with a high-speed stirrer to form a pre-emulsion to produce an emulsion solution.

A reactor equipped with a reflux condenser, a thermometer, and a stirrer was charged with 32 parts of deionized exchanged water, 0.1 part of sodium bicarbonate, and 0.65 part of "Adekaria Soap SE-1025N". The temperature was raised to 78 ° C. while stirring. While maintaining the same temperature, 0.15 parts of potassium persulfate was charged, and after 5 minutes from the introduction, the above-mentioned emulsion solution was uniformly dropped over 3 hours. 30 minutes after the completion of dropping, potassium persulfate 1
% Aqueous solution was added, and the mixture was further stirred at the same temperature for 2 hours, cooled to 50 ° C., and diluted with dimethylethanolamine 0.1%.
15 parts were added to complete the reaction. The resulting aqueous resin dispersion A had a solids concentration of 45% and a pH of 7.5.

<Preparation of Aqueous Resin Dispersion B> 100 parts of ethylene glycol monobutyl ether was added to a reactor equipped with a reflux condenser and a stirrer, and stirred at 100 ° C.
Was heated. Next, 50 parts of isobutyl methacrylate,
A mixed solution of 31.5 parts of 2-ethylhexyl methacrylate, 10 parts of γ-methacryloxypropyltrimethoxysilane, 8.5 parts of acrylic acid, and 2.5 parts of t-butylperoxy-2-ethylhexanoate was heated at 100 ° C. 3
The mixture was added dropwise over a period of time, then the temperature was raised to 105 ° C. and maintained for 2 hours to terminate the reaction, the solid content was 50%, and the acid value of the resin was 65.
mgKOH / g, a silyl group-containing vinyl resin solution (a) having a number average molecular weight of 10,000 was produced.

In a reactor equipped with a reflux condenser and a stirrer,
Partially hydrolyzed condensate of methyltrimethoxysilane [“S
R2402 "(manufactured by Dow Corning Toray Co., Ltd .; solid content 100%), and 8 parts of methyltrimethoxysilane.
Parts, 1.7 parts of dimethyldimethoxysilane, 25 parts of the above silyl group-containing vinyl resin solution (a), and 10 parts of isopropanol, and mixed.
And 0.05 part of 0.1 N hydrochloric acid, and reacted at 60 ° C. for 3 hours. Next, 0.3 parts of aluminum monoacetylacetate bis (ethylacetoacetate) and 0.8 parts of ion-exchanged water were added, and the mixture was further reacted at 60 ° C. for 3 hours. Subsequently, 0.6 parts of triethylamine and 37 parts of water were added, and the mixture was stirred at 50 ° C. for 1 hour, and then reduced in pressure [1.3 × 10 3
After removing the solvent under ⁴ Pa (100 Torr), dilution was adjusted with water to a solid content concentration of 35% to prepare an aqueous resin dispersion B.

<Preparation of curing agent C> In a reactor equipped with a reflux condenser and a stirrer, (a) tetraethoxysilane
0 part (72 mMol) and (b) 65.6 parts of tetramethylammonium hydroxide-10% methanol solution (7
2mMol), and (c) 13.0 parts of ion-exchanged water (7
22 mMol) and stirred at 20 ° C. for 6 hours to obtain a curing agent C composed of a cage-like ammonium silicate compound.

<Preparation of curing agent D> In a reactor equipped with a reflux condenser and a stirrer, (a) tetraethoxysilane
0 part (106 mMol) and 64.2 parts (106 m) of (b) tetramethylammonium hydroxide-15% aqueous solution
Mol) and stirred at 20 ° C. for 6 hours to obtain a curing agent D composed of a cage-like ammonium silicate compound.

Examples 1-4 and Comparative Examples 1-2 The aqueous dispersions A and B and the curing agents C and D were mixed in the proportions shown in Table 1 immediately before coating to prepare an aqueous coating composition. In Comparative Example 3, conventional curing agents shown in Table 1 were used as curing agents. For the obtained aqueous coating composition, a coated plate was prepared as described below, and the appearance and hardness of the obtained coating film, hardness, stain resistance, hot water resistance, weather resistance, and alkali resistance were tested. Are shown in the lower part of Table 1, respectively.

<Coating Film Performance Test> A gypsum slag perlite plate (thickness: 12 mm) was used as a material, and a polyisocyanate prepolymer solution sealer [“V-Seran.
100 sealer "(manufactured by Dainippon Paint Co., Ltd.)] (100% dilution with a solution of butyl acetate: xylene = 1: 1) by spray coating so that the coating amount is 90 to 100 g / m ² (wet mass). did. This was dried at 100 ° C. for 5 minutes. Next, as a base paint, an acrylic silicone resin-based paint [“V-Seran 500 Enamel” (Dainippon Paint Co., Ltd.)
(Butyl acetate: xylene = 1: 1 solution 40%)
(Dilution) was spray-coated such that the coating amount was 80 to 90 g / m ² (wet mass). This was dried at 120 ° C. for 15 minutes. Next, Examples 1 to 4 having the formulations shown in Table 1
And the coating amount of each coating composition of Comparative Examples 1-2 was (130 ±
10) Spray coating was performed so as to give g / m ² (wet mass). This was dried at 80 ° C. for 12 minutes, and further dried at room temperature for 3 days to prepare a coated plate. In addition, the test method and evaluation were performed based on the following.

Appearance: The appearance of the coating film formed on the coated plate was visually judged. Hardness: Pencil hardness measured according to JIS K 5400 Hot water resistance: The coated plate was immersed in water at 80 ° C.
During the immersion and after the coating film was dried, it was visually judged. Evaluation ◎ ・ ・ ・ No change during immersion and after coating film drying ○ ・ ・ ・ Slight whitening during immersion, but no change after coating film drying △ ・ ・ ・ Whitening during immersion severe, after coating film drying There are slight changes such as decrease in gloss and whitening. × ・ ・ ・ Severe whitening during immersion, and large changes such as decrease in gloss and whitening after drying of the coating film.

Stain resistance: Twenty-four hours after the application of the red and black magic inks, they were wiped off with a cloth wetted with n-butanol, and decontamination properties were visually evaluated. Evaluation ◎ ・ ・ ・ Complete removal ○ ・ ・ ・ Extremely slight contamination △ ・ ・ ・ Slight contamination × ・ ・ ・ Remarkable contamination

Weather resistance: Sunshine weather-o-meter 3000 hours evaluation ○: no change in appearance of coating film, gloss retention of 95% or more △: slight change in appearance of coating film, gloss retention: 80 to 80%
94% ×: The change in the coating film is remarkable, the gloss retention is less than 80%.
After immersion at 0 ° C. for 10 days, the coating film surface was visually evaluated. Evaluation ○ ・ ・ ・ No change △ ・ ・ ・ Slight whitening of coating film × ・ ・ ・ Coating of coating film surface

[Table 1] Table 1

As is clear from Table 1, Examples 1 to 4, which are the aqueous coating compositions of the present invention, had excellent coating performance. On the other hand, Comparative Examples 1 and 2 containing no curing agent and Comparative Example 3 using a conventional curing agent were inferior in stain resistance, hot water resistance, alkali resistance and the like.

The aqueous coating composition of the present invention can form a coating film having excellent hot water resistance, weather resistance, stain resistance, solvent resistance, alkali resistance and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08G 77/442 C08G 77/442 C09D 157/00 C09D 157/00 183/02 183/02 183/04 183 / 04 183/07 183/07 (72) Inventor Hiroharu Sasaki 7-1414-46, Shimonagata, Nishinasuno-machi, Nasu-gun, Tochigi Prefecture (72) Inventor Kazuyoshi 1-981 Shimonagata, Nishinasuno-machi, Nasu-gun, Tochigi F-term (reference) 4J011 PA99 PC02 4J026 AB44 BA04 BA05 BA25 BA27 BA43 BB02 BB03 DB04 GA06 4J035 BA04 CA13M CA14M CA181 EB02 EB04 EB10 FB01 GA02 4J038 CC021 CD021 CG081 CG141 DL021 DL031 DL111 GA06 GA03 GA03 GA03 GA03 GA03 GA03 GA03 GA03 PC03

Claims (3)

[Claims] (I) an aqueous resin having a hydrolyzable silyl group in the molecule; and (II) (a) Formula (1), Si (OR ¹ ) _{4 wherein} R ¹ is carbon To 5 alkyl groups. ]
Organosilane represented in the formula ^{(2), R 2 Si (} OR 3) 3 wherein, R ² is an organic group having 1 to 8 carbon atoms, R ³ is
It is an alkyl group having 1 to 5 carbon atoms. ] And the molar ratio of the two is [(0.
3 to 1.0): 0.5 to 1.5 mol of the organosilane compound (0.7 to 0)] and 1.0 mol of the quaternary ammonium compound (b) in the presence of water An aqueous coating composition comprising a cage-like ammonium silicate compound obtained by the above method. Wherein said aqueous resin (I) is, (c) Equation _{^{(3), R 4 n Si}} (OR 5) 4-n wherein, R ⁴ is an organic group having 1 to 8 carbon atoms , R ⁵ is
It is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2. And (d) (i) a polymerizable unsaturated group having a polymerizable unsaturated group and a hydrolyzable group directly bonded to a silicon atom in the molecule. (Ii) 1 to 50% by mass of a monomer;
Polymerizable unsaturated monomer other than the component (i) 99 to 50
The aqueous coating composition according to claim 1, wherein the aqueous coating composition is an aqueous resin obtained by emulsion polymerization of 10% to 2000% by mass of a monomer component consisting of 3. The aqueous resin (I) comprises (e) 100 parts by mass of an organosilane represented by the formula (3) and / or a partially hydrolyzed condensate thereof, and (f) a hydrolyzable silyl group or a hydroxyl group. Neutralization of a hydrolysis-condensation reaction product of 5-200 parts by mass of a silyl group-containing vinyl resin having a silyl group having a silicon atom and an acid value of 20 to 150 mgKOH / g, with a neutralizing agent The aqueous coating composition according to claim 1, which is an aqueous resin obtained by the above method.