JP2001123074A - Aqueous resin composition and aqueous coating composition using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous resin composition improved in water resistance, weather resistance and stain resistance, and especially stain resistance, and an aqueous coating composition using the same. SOLUTION: The aqueous resin composition is prepared by solution polymerizing 0.5-50 wt.% polymerizable unsaturated monomer (A) having hydrolyzable silyl groups, 1-20 wt.% polymerizable unsaturated monomer (B) having at least one kind of ion-forming groups, and [100-A-B] wt.% other polymerizable unsaturated monomer in the presence of 5-100 wt.%, based on the total polymerizable unsaturated monomers, colloidal silica (D) dispersed in a non-aqueous solvent in terms of SiO2 amount and 0.1-5 wt.%, based on the total polymerizable unsaturated monomers, compound (E) having at least one hydrolyzable silyl group and one mercapto group in one molecule, and emulsifying the obtained resin solution by adding water to the solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water-based paint composition applied to undercoats, overcoats, linings and the like of various materials such as woody materials, plastics, papers, metals, and ceramic inorganic materials. The present invention relates to a water-based dispersible resin composition used and a water-based coating composition using the same.

[0002]

2. Description of the Related Art In recent years, in the field of coating agents,
From the viewpoint of environmental problems, conversion from an organic solvent system to an aqueous system is being performed. However, conventional water-based coating agents do not have a crosslinkable functional group, and therefore have the disadvantage that the water resistance, solvent resistance, adhesion, and weather resistance of the coating film are inferior to organic solvent-based coating agents. . In addition, a water-based coating agent has been required to have stain resistance from the viewpoint of maintenance-free.

[0003] Therefore, as a water-based coating agent having a crosslinkable functional group, a water-based coating agent using a resin composition obtained by emulsifying a resin having an alkoxysilyl group, which is a kind of hydrolyzable silyl group, has been proposed (for example, And JP-A-3-21610). By using such a water-based coating agent, a water-based coating composition having improved water resistance, solvent resistance, and adhesion has been obtained, but the stain resistance has not been sufficient yet.

As a method for improving the stain resistance of a coating film,
There is known a method of imparting a so-called “self-cleaning” function of hydrophilizing a coating film and removing contaminants with rainwater. So far, (1) a method of blending a water-dispersible colloidal silica known as a compound imparting a `` self-cleaning '' function into a highly weatherable water-based acrylic silicone emulsion or the like, and (2) a water-dispersible method in the presence of an emulsifier A method is known in which colloidal silica, an acrylic monomer, and a monomer having a hydrolyzable silyl group are emulsion-polymerized to obtain an aqueous resin composition.
However, in the method (1), since the colloidal silica and the emulsion are physically blended, if the amount of the water-dispersible colloidal silica is increased to increase the stain resistance, the film forming property of the coating film rapidly increases. There is a problem that the water resistance and the weather resistance are deteriorated. In the method (2), since the reactivity between the water-dispersible colloidal silica and the monomer is low, a chemical bond between the colloidal silica and the monomer is not sufficiently formed, and when the amount of the water-dispersible colloidal silica is increased, As in the case of (2), the film forming property of the coating film deteriorates. Further, there is a problem that the water resistance of the coating film is reduced by the emulsifier used for stably proceeding the emulsion polymerization.

[0005]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to use colloidal silica capable of imparting a function of "self-cleaning" to provide water resistance, weather resistance and stain resistance. It is an object of the present invention to provide a water-based resin composition having improved properties, especially stain resistance, and a water-based coating composition using the same.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a polymerizable unsaturated monomer having a hydrolyzable silyl group and a polymerizable unsaturated monomer having at least one kind of ion-forming group. Monomer and another polymerizable unsaturated monomer,
An emulsion is obtained by performing solution polymerization in the presence of colloidal silica dispersed in a non-aqueous solvent and a compound having at least one hydrolyzable silyl group and a mercapto group in one molecule, and adding water to the obtained resin solution. Thus, the present inventors have found that an aqueous resin composition having improved water resistance, weather resistance, and stain resistance, particularly, stain resistance, can be obtained, thereby completing the present invention.

That is, the present invention relates to a polymerizable unsaturated monomer having a hydrolyzable silyl group (A) of 0.5 to 50% by weight.
And 1 to 20% by weight of a polymerizable unsaturated monomer (B) having at least one ion-forming group, and another polymerizable unsaturated monomer (C) [100- (A)-(B )〕weight%
Is expressed in terms of SiO ₂ , and is colloidal silica dispersed in a non-aqueous solvent in an amount of 5 to 100% by weight based on the total polymerizable unsaturated monomers ((A) + (B) + (C)). (D)
And a total polymerizable unsaturated monomer ((A) + (B) + (C))
Solution polymerization in the presence of 0.1 to 5% by weight of a compound (E) having at least one hydrolyzable silyl group and mercapto group in one molecule, and adding water to the obtained resin solution It is an aqueous resin composition obtained by emulsifying by doing.

The above aqueous resin composition is preferably obtained by removing the polymerization solvent after emulsification. Further, the present invention is an aqueous coating composition using the above aqueous resin composition.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, each component for copolymerization of a resin in the present invention will be described. In the present invention, a polymerizable unsaturated monomer (A) having a hydrolyzable silyl group is used as one of the components for copolymerization. By using this monomer (A) as a component for polymerization, a hydrolyzable silyl group acts as a crosslinkable functional group at the time of coating film formation, thereby improving the water resistance, solvent resistance and adhesion of the coating film. Becomes possible.

The polymerizable unsaturated monomer having a hydrolyzable silyl group (A) includes, for example, a polymerizable unsaturated monomer having a silyl group represented by the following general formula (1).

[0011]

Embedded image

(Wherein R ¹ , R ² , and R ³ are the same or different and are each a halogen atom, an alkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, an acyloxy group, a hydroxyl group, an amino group, an amino group) Represents an oxy group or an alkylthio group, provided that at least one of R ^{1 to} R ³ is a halogen atom, an alkoxy group or a hydroxyl group.) The hydrolyzable silyl group is usually at least one of R ^{1 to} R ^3. One has a halogen atom, an alkoxy group, and a hydroxyl group.

The halogen atom of the silyl group represented by the formula (1) includes, for example, fluorine, chlorine, bromine, iodine and the like, and is usually a chlorine atom. Examples of the alkyl group include a C _1-10 alkyl group such as a methyl, ethyl, propyl, butyl, pentyl, and hexyl group. Here, C _1-10 means “having 1 to 10 carbon atoms”, and the same applies hereinafter. The aryl group includes, for example, a C _6-10 aryl group such as a phenyl group, and the aralkyl group includes, for example, a C _7-10 aralkyl group such as a benzyl group.

Examples of the alkoxy group include C _1-16 alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, t-butoxy, pentyloxy, hexyloxy, octyloxy, decyloxy, dodecyloxy and the like. Is included. Preferred alkoxy groups are C _1-4 alkoxy groups, especially methoxy groups and ethoxy groups. The alkoxy group also includes, for example, an alkoxy-substituted alkoxy group such as a methoxyethoxy group.

The aryloxy group includes, for example, a C _6-10 aryloxy group such as a phenoxy group. Acyloxy groups include, for example, C _2-8 acyloxy groups such as acetyloxy, propionyloxy and butyryloxy groups.

The amino group includes, for example, an amino group which may have a substituent such as a dimethylamino group. The aminooxy group has a substituent such as a dimethylaminooxy group. And an optionally substituted aminooxy group. Examples of the alkylthio group include a C _1-8 alkylthio group such as a methylthio and ethylthio group.

The polymerizable unsaturated monomer (A) having a hydrolyzable silyl group includes, for example, compounds represented by the following general formulas (2) to (13).

[0018]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group is shown, and R ⁵ is a hydrogen atom or a methyl group. X represents a fluorine, chlorine, bromine or iodine atom. a shows the integer of 0-2. )

Such compounds include, for example, vinyltrichlorosilane, vinylmethyldichlorosilane, vinyldimethylchlorosilane, vinylmethylphenylchlorosilane, isopropenyltrichlorosilane, isopropenylmethyldichlorosilane, isopropenyldimethylchlorosilane, isopropenylmethylphenyl Chlorosilane and the like can be mentioned.

[0021]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group is shown, and R ⁵ is a hydrogen atom or a methyl group. X represents a fluorine, chlorine, bromine or iodine atom. a represents an integer of 0 to 2;
Indicates an integer of 12. Examples of such compounds include allyltrichlorosilane, allylmethyldichlorosilane, allyldimethylchlorosilane and the like.

[0023]

Embedded image

Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group is shown, and R ⁵ is a hydrogen atom or a methyl group. X represents a fluorine, chlorine, bromine or iodine atom. a represents an integer of 0 to 2;
Indicates an integer of 12. Examples of such a compound include 2- (meth) acryloxyethyltrichlorosilane, 3- (meth) acryloxypropyltrichlorosilane, 2- (meth) acryloxyethylmethyldichlorosilane, and 3- (meth) Acryloxypropylmethyldichlorosilane, 2- (meth) acryloxyethyldimethylchlorosilane, 3- (meth)
Acryloxypropyldimethylchlorosilane and the like can be mentioned.

[0025]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group. a shows the integer of 0-2. )

Examples of such compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, vinyltri (hexyloxy) silane, vinyltri (octyloxy) silane, vinyltri (decyloxy) silane, and vinyltri (dodecyl). Oxy) silane, vinyldimethoxymethylsilane, vinyldiethoxymethylsilane, vinylmethoxydimethylsilane, vinylethoxydimethylsilane, vinylbutoxydimethylsilane, vinyldiphenylethoxysilane,
Isopropenyl trimethoxy silane, isopropenyl triethoxy silane isopropenyl tributoxy silane,
Isopropenyltri (hexyloxy) silane, isopropenyltri (octyloxy) silane, isopropenyltri (decyloxy) silane, isopropenyltri (dodecyloxy) silane, isopropenyldimethoxymethylsilane, isopropenyldiethoxymethylsilane, isopropenyl Examples include methoxydimethylsilane, isopropenylethoxydimethylsilane, isopropenylbutoxydimethylsilane, vinyltris (2-methoxyethoxy) silane, and the like.

[0028]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group, R ⁷ represents a C _1-12 alkylene group or a phenylene group. a shows the integer of 0-2. )

Examples of such compounds include allyltrimethoxysilane, vinyldecyltrimethoxysilane, vinyloctyltrimethoxysilane, vinylphenyltrimethoxysilane, vinylphenyldimethoxymethylsilane, vinylphenyldimethoxydimethylsilane,
Examples include isopropenylphenyltrimethoxysilane, isopropenylphenyldimethoxymethylsilane, and isopropenylphenylmethoxydimethylsilane.

[0031]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group; R ⁵ represents a hydrogen atom or a methyl group; R ⁶ represents a C _1-16 alkoxy group; a represents an integer of 0 to 2; Indicates an integer. )

Such compounds include, for example, 2-
(Meth) acryloxyethyltrimethoxysilane, 2-
(Meth) acryloxyethyltriethoxysilane, 3-
(Meth) acryloxypropyltrimethoxysilane, 3
-(Meth) acryloxypropyltriethoxysilane,
Examples thereof include 3- (meth) acryloxypropylmethyldimethoxysilane, 3- (meth) acryloxypropyldiethoxymethylsilane, and 3- (meth) acryloxypropyltris (2-methoxyethoxy) silane.

[0034]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group. a represents an integer of 0 to 2; n represents an integer of 1 to 12; )

Examples of such a compound include, for example, 3-
(Allyloxycarbonyl-o-phenylene-carboxy) propyltrimethoxysilane, 3- (allyloxycarbonyl-o-phenylene-carboxy) propyldimethoxymethylsilane, 3- (allyloxycarbonyl-o-phenylene-carboxy) propylmethoxydimethyl Silane, 3- (isopropenylmethyleneoxycarbonyl-o-phenylene-carboxy) propyltrimethoxysilane, 3- (isopropenylmethyleneoxycarbonyl-o-phenylene-carboxy) propyldimethoxymethylsilane, 3- (isopropenylmethyleneoxycarbonyl —O-phenylene-carboxy) propylmethoxydimethylsilane and the like.

[0037]

Embedded image

Such compounds include, for example, 3-
(Vinylphenylamino) propyltrimethoxysilane, 3- (vinylphenylamino) propyltriethoxysilane, 3- (vinylbenzylamino) propyltrimethoxysilane, 3- (vinylbenzylamino) propyltriethoxysilane and the like.

[0039]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group. a shows the integer of 0-2. )

Such compounds include, for example, 3-
[Vinylphenylenemethylene (ethylenediamino)] propyltrimethoxysilane, 3- [isopropenylphenylenemethylene (ethylenediamino)] propyltrimethoxysilane and the like can be mentioned.

[0042]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group. a represents an integer of 0 to 2; n represents an integer of 1 to 12; )

Such compounds include, for example, 2-
Examples thereof include (vinyloxy) ethyltrimethoxysilane, 3- (vinyloxy) propyltrimethoxysilane, 4- (vinyloxy) butyltriethoxysilane, and 2- (isopropenyloxy) ethyltrimethoxysilane.

[0045]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group, R ⁹ is -CH ₂ O-or -CH ₂ OCO- Show. a represents an integer of 0 to 2; n represents an integer of 1 to 12; )

Such compounds include, for example, 3-
(Allyloxy) propyltrimethoxysilane, 10-
(Allyloxycarbonyl) decyltrimethoxysilane, 3- (isopropenylmethyleneoxy) propyltrimethoxysilane, 10- (isopropenylmethyleneoxycarbonyl) decyltrimethoxysilane and the like.

[0048]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ⁶ represents a C _1-16 alkoxy group. a represents an integer of 0 to 2, n represents an integer of 1 to 12, and m represents an integer of 1 to 12. )

Such compounds include, for example, 3-
[(Meth) acryloxyethyleneoxy] propyltrimethoxysilane, 3-[(meth) acryloxyethyleneoxy] propyldimethoxymethylsilane, and the like.

The polymerizable unsaturated monomer (A) having a hydrolyzable silyl group is, for example, a divinyl group-containing compound such as divinyldimethoxysilane, divinyldiethoxysilane, divinyldi (β-methoxyethoxy) silane. There may be.

The polymerizable unsaturated monomers (A) having a hydrolyzable silyl group can be used alone or in combination of two or more. Preferred silyl group-containing monomers include
In terms of handling, economy and suppression of side reactions,
For example, a vinyl monomer containing an alkoxysilyl group may be mentioned.

In the present invention, a polymerizable unsaturated monomer (B) having at least one kind of ion-forming group is used as one of the components for copolymerizing a resin. This monomer (B)
By using as a component for polymerization, the obtained polymer has an ion-forming group, and the polymer can be easily emulsified. Examples of the ion-forming group include a cation-forming group such as an amino group and an imide group, and an anion-forming group such as a carboxyl group.

Accordingly, examples of the monomer (B) having a cation-forming group include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, and diethylaminopropyl (meth). Acrylate, dimethylaminoethyl (meth) acrylamide, (meth)
Acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyltrimethylammonium methosulfate and the like can be mentioned. Such monomers (B) having a cation-forming group can be used alone or in combination of two or more.

Examples of the monomer (B) having an anion-forming group include carboxyethyl (meth) acrylate, carboxypropyl (meth) acrylate, vinyl carboxylic acid [(meth) acrylic acid, ethacrylic acid, crotonic acid , Sorbic acid, maleic acid, itaconic acid, cinnamic acid, etc.], vinyl sulfonic acid [vinyl sulfonic acid, allyl sulfonic acid, vinyl toluene sulfonic acid, styrene sulfonic acid, etc.], (meth) acryl sulfonic acid [(meth) acrylic] Sulfoethyl acid, sulfopropyl (meth) acrylate], (meth) acrylamidosulfonic acid [such as 2-acrylamido-2-methylpropanesulfonic acid] and the like. The monomers (B) having such an anion-forming group can be used alone or in combination of two or more.

In the present invention, in addition to the polymerizable unsaturated monomer having a hydrolyzable silyl group (A) and the polymerizable unsaturated monomer having an ion-forming group (B), other The polymerizable unsaturated monomer (C) is copolymerized. The type of the polymerizable unsaturated monomer (C) is appropriately selected from various known polymerizable unsaturated monomers according to the application to which the aqueous resin composition is applied.

Examples of such a polymerizable unsaturated monomer (C) include (meth) acrylic monomers, aromatic vinyls, vinyl esters, halogen-containing vinyls, vinyl ethers (for example, vinyl Ethyl ether),
Vinyl ketones (for example, methyl vinyl ketone, etc.),
Vinyl heterocyclic compounds (eg, N-vinylpyrrolidone,
Examples thereof include N-vinyl compounds such as N-vinylimidazole, vinyl pyridine and the like, olefin monomers (eg, eletin, propylene and the like), allyl compounds (eg, allyl ester such as allyl acetate).
This polymerizable unsaturated monomer (C) can be used alone or in combination of two or more.

The (meth) acrylic monomer of the polymerizable unsaturated monomer (C) includes, for example, (meth) acrylate,
(Meth) acrylamides, (meth) acrylonitrile and the like are included.

The (meth) acrylate includes, for example, alkyl (meth) acrylate [eg, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate,
Hexyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate,
C _1-18 alkyl (meth) acrylates such as lauryl (meth) acrylate, etc.], cycloalkyl (meth)
Acrylates (eg, cyclohexyl (meth) acrylate, etc.), aryl (meth) acrylates (eg, phenyl (meth) acrylate, etc.), aralkyl (meth) acrylates (eg, benzyl (meth) acrylate, etc.), hydroxyalkyl (meth) acrylates [For example, hydroxy-C such as 2-hydroxyethyl and 2-hydroxypropyl ((meth) acrylate)
_2-4 alkyl (meth) acrylate, etc.], glycidyl (meth) acrylate, dialkylamino-alkyl (meth) acrylate [for example, 2- (dimethylamino) ethyl (meth) acrylate, 2- (diethylamino) ethyl (meth) acrylate Di C _1-4 alkylamino-C _2-4 alkyl (meth) acrylate, etc.]
And so on.

(Meth) acrylamides include, for example,
(Meth) acrylamide, hydroxyalkyl (meth)
Acrylamide [for example, N-hydroxy-C _1-4 alkyl (meth) acrylamide such as N-methylol (meth) acrylamide], alkoxyalkyl (meth) acrylamide [for example N-methoxymethyl (meth) acrylamide or other N- C _1-4 alkoxy-C
_1-4 alkyl (meth) acrylamide, etc.], diacetone (meth) acrylamide, etc.

Preferred (meth) acrylic monomers include, for example, (meth) acrylates [eg, C _1-18 alkyl (meth) acrylate, hydroxy-C _2-4 alkyl (meth) acrylate, glycidyl (meth) acrylate (Meth) acrylamides, and the like. (Acrylates, di C _1-4 alkylamino-C _2-4 alkyl (meth) acrylates).

Further preferred (meth) acrylic monomers include C _2-10 alkyl acrylate, C _1-6 alkyl methacrylate, hydroxy-C _2-3 alkyl (meth) acrylate, glycidyl (meth) acrylate,
And di C _1-3 alkylamino -C _2-3 alkyl (meth) acrylate.

The aromatic vinyls include, for example, styrene,
α-methylstyrene, vinyltoluene, etc.
Styrene is often used. Vinyl esters include
For example, vinyl acetate, vinyl propionate, vinyl versatate (such as VeoVa) and the like are included. Halogen-containing vinyls include, for example, vinyl chloride, vinylidene chloride, and the like. Further, as the other polymerizable unsaturated monomer (C), a compound containing a silyl group represented by the following general formulas (14) to (16) may be used.

[0064]

Embedded image

(Wherein R^FourIs C_1-10Alkyl group, C_6-10
Aryl group or C_7-10An aralkyl group;^FiveIs hydrogen
An atom or a methyl group;^TenAnd R¹¹Are the same or different
C _1-10Shows an alkyl group. a represents an integer of 0 to 2
You. Examples of such a compound include vinyl bis (dimene).
Tylamino) methylsilane and the like.

[0066]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group is shown, R ⁵ is a hydrogen atom or a methyl group, and R ¹² is a C _2-6 acyl group. a shows the integer of 0-2. Examples of such compounds include vinyl tri (acetyloxy) silane, vinyl di (acetyloxy) methyl silane, and the like.

[0068]

Embedded image

(Wherein R ⁴ is a C _1-10 alkyl group, C _6-10
An aryl group or a C _7-10 aralkyl group, R ⁵ represents a hydrogen atom or a methyl group, R ¹³ represents a C _6-10 aryl group. a shows the integer of 0-2. As such a compound, for example, vinyltriphenoxysilane and the like can be mentioned.

As such a polymerizable unsaturated monomer (C), usually, a hard monomer [for example, a glass transition temperature of 80 to 120 of methyl (meth) acrylate, styrene or the like] is used.
° C. (in particular 90 to 105 ° C.) and about homopolymer monomer components for forming the, soft monomer [e.g., a glass transition temperature -85 ° C., such as acrylic acid C _2-10 alkyl ester
-10 ° C (especially -85 ° C to -20 ° C) to form a homopolymer] in many cases.

As described above, when a hard monomer and a soft monomer are usually used as the polymerizable unsaturated monomer (C), the compounding ratio thereof is not particularly limited. For example, 10 to 90% by weight of the hard monomer (for example, 15-85% by weight, preferably 20-80% by weight, more preferably 2%
5 to 75% by weight, especially 30 to 70% by weight, soft monomer 10 to 90% by weight (for example 15 to 85% by weight, preferably 20 to 80% by weight, more preferably 25 to 75% by weight).
%, Especially 30 to 70% by weight).

In the present invention, colloidal silica (D) dispersed in a non-aqueous solvent is used as one of the components for resin copolymerization. Colloidal silica is a colloid of silicon dioxide or a hydrate thereof, and in the present invention, any type of colloidal silica can be used as long as it is dispersed in a non-aqueous solvent. Further, the method for producing colloidal silica is not limited.

By using colloidal silica (D) dispersed in the non-aqueous solvent as a polymerization component, a polymer in which an organic component and an inorganic component are hybridized is obtained.
The hydrophilicity and water resistance of the polymer can be improved. That is, a hydrolyzable silyl group in the monomer (A),
By reacting with Si-OH on the surface of the colloidal silica (D), an organic / inorganic hybrid polymer is obtained.

Examples of the colloidal silica (D) dispersed in a non-aqueous solvent include colloidal silica dispersed in alcohol, for example, colloidal silica dispersed in methyl alcohol, colloidal silica dispersed in ethyl alcohol,
Colloidal silica dispersed in isopropyl alcohol (for example, IPA-ST, manufactured by Nissan Chemical Industries, Ltd.) and the like. The amount of the non-aqueous solvent based on SiO ₂ is not particularly limited, but is, for example, about 100 to 1000% by weight based on SiO ₂ .

In the present invention, the compound (E) having at least one hydrolyzable silyl group and mercapto group in one molecule is used as a chain transfer agent during polymerization. Examples of such compound (E) include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyldimethoxymethylsilane, 3-mercaptopropylmethoxydimethylsilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldiethoxysilane Examples include methylsilane and 3-mercaptopropylethoxydimethylsilane. By using the compound (E) as a chain transfer agent, a hydrolyzable silyl group derived from the monomer (A) easily reacts with Si—OH on the surface of the colloidal silica (D) in a polymerization process, A resin in which an organic component and an inorganic component are hybridized can be obtained.

The amounts of the polymerizable unsaturated monomers (A), (B) and (C), the colloidal silica (D) and the compound (E) used in the present invention will be described.

The hydrolyzable silyl group-containing polymerizable unsaturated monomer (A) comprises 0.5 to 5 of the total polymerizable unsaturated monomers.
Although 0% by weight is used, 0.5 to 30% by weight is particularly preferable. When the proportion of the monomer (A) is less than 0.5% by weight,
There may be a problem that the water resistance, solvent resistance and adhesion of the cured coating film are deteriorated. On the other hand, if it exceeds 50% by weight, there may be a problem that the polymerization stability and the storage stability of the aqueous resin composition decrease.

The polymerizable unsaturated monomer containing an ion-forming group (B) is used in an amount of 1 to 20% by weight, preferably 2 to 10% by weight, based on the total amount of the polymerizable unsaturated monomers. Monomer (B)
Is less than 1% by weight, agglomerates are formed at the time of emulsification, while if it exceeds 20% by weight, the water resistance of the formed coating film is deteriorated. Other polymerizable unsaturated monomers (C) account for the balance of the monomers (A) and (B).

The colloidal silica (D) dispersed in the non-aqueous solvent is represented by the amount as SiO _{2 and} is 5 to the total polymerizable unsaturated monomer ((A) + (B) + (C)). -10
Although 0% by weight is used, 10 to 80% by weight is preferable. If the amount of colloidal silica (D) is less than 5% by weight, the hydrophilicity of the formed coating film is insufficient, and the expected effect of stain resistance cannot be obtained. On the other hand, if it exceeds 100% by weight, the water resistance of the formed coating film deteriorates.

The compound (E) having a hydrolyzable silyl group and a mercapto group can be obtained by reacting a fully polymerizable unsaturated monomer ((A) +
(B) + (C)) is used in an amount of 0.1 to 5% by weight,
It is preferably from 0.5 to 5% by weight, more preferably from 1 to 3% by weight. When the amount of the compound (E) is less than 0.1% by weight, the reaction between the copolymer obtained by solution polymerization and Si-OH on the surface of the colloidal silica (D) is insufficient, and the resulting coating film The film forming property deteriorates. On the other hand, if it exceeds 5% by weight,
The molecular weight of the copolymer obtained by solution polymerization decreases, and the weather resistance and adhesion of the formed coating film deteriorate.

In the present invention, each of the polymerizable unsaturated monomers (A), (B) and (C) is subjected to solution polymerization in the presence of the colloidal silica (D) and the compound (E), The resulting resin solution is emulsified by adding water to obtain an aqueous resin composition.

That is, the above-mentioned polymerizable unsaturated monomer components ((A), (B) and (C)), the above-mentioned colloidal silica (D) and compound (E) are mixed, and an appropriate organic solvent is used. The polymer is copolymerized under the following conditions, and the polymer is converted into an alkali (eg, an alkylamine such as triethylamine, a cyclic amine such as morpholine, an alkanolamine such as triethanolamine, pyridine, ammonia, etc.) and an acid [eg,
Inorganic acids (eg, hydrochloric acid, sulfuric acid, etc.), organic acids (eg,
Carboxylic acid such as acetic acid and propionic acid, and sulfonic acid). The polymerization operation may be of a batch type or a continuous type.

The organic solvent used in the solution polymerization includes, for example, alcohols (eg, ethanol, isopropanol, n-butanol, etc.), aromatic hydrocarbons (eg,
Benzene, toluene, xylene, etc.), aliphatic hydrocarbons (eg, pentane, hexane, heptane, etc.), alicyclic hydrocarbons (eg, cyclohexane, etc.), esters (eg, ethyl acetate, n-butyl acetate, etc.), ketones (Eg, acetone, methyl ethyl ketone, etc.), ether (eg, diethyl ether, dioxane, tetrahydrofuran, etc.) and the like can be used. These organic solvents may be used alone or in combination of two or more. As the organic solvent, usually, alcohols such as isopropyl alcohol, aromatic hydrocarbons such as toluene, ketones such as methyl ethyl ketone, and the like are used.

The amount of the organic solvent used is not particularly limited. For example, the amount of the organic solvent based on the total amount of the polymerizable unsaturated monomers is (0.1 / 1 to 5/1) by weight, preferably (0/1). .5
/ 1 to 2/1).

In the solution polymerization, the polymerization may be started by irradiation with an electron beam or ultraviolet rays, but the polymerization is often started using a polymerization initiator. Examples of the polymerization initiator include, for example, azo compounds [eg, azobisisobutyronitrile, 2,2-azobis (2,4-dimethylvaleronitrile), azobiscyanovaleric acid, 2,2-azobis (2-
Amidinopropane) hydrochloride, 2,2-azobis (2-amidinopropane) acetate, etc.], inorganic peroxides (for example, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide), organic Peroxides [eg benzoyl peroxide, di-
t-butyl peroxide, cumene hydroperoxide, di (2-ethoxyethyl) peroxydicarbonate] and redox catalyst [for example, sulfite or bisulfite (for example, alkali metal salt, ammonium salt, etc.), L-ascorbic acid] , A catalyst system comprising a combination of a reducing agent such as erythorbic acid and an oxidizing agent such as a persulfate (eg, an alkali metal salt or an ammonium salt) or a peroxide]. The polymerization initiators can be used alone or in combination of two or more.

The amount of the polymerization initiator to be used is, for example, 0.001 to 20% by weight based on the total weight of the polymerizable unsaturated monomer,
Preferably 0.01 to 10% by weight (for example, 0.1 to 1%)
0% by weight).

The reaction temperature in the solution polymerization is, for example, 5
The temperature is 0 to 150 ° C, preferably about 70 to 130 ° C.
The reaction time is, for example, about 1 to 10 hours, preferably about 2 to 7 hours. The end point of the polymerization is determined by the absorption of a double bond (1648 cm ^-1 ) in the infrared absorption spectrum.
Can be confirmed by disappearance of unreacted monomers or disappearance of unreacted monomers using gas chromatography.

When the polymer contains a cationic group such as an amino group, an imide group or a cation-forming group,
When an acid is used, hydrophilicity is improved, and the polymer can be easily dissolved or emulsified. Such acids include, for example, inorganic acids (eg, hydrochloric acid, phosphoric acid, sulfuric acid, nitric acid, etc.) and organic acids [eg, saturated aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid; oxalic acid, adipic acid Unsaturated aliphatic monocarboxylic acids such as (meth) acrylic acid; unsaturated aliphatic polycarboxylic acids such as maleic acid and itaconic acid; aliphatic oxycarboxylic acids such as lactic acid and citric acid Etc.].

When the polymer has an acidic group such as a carboxyl group, the use of a base can easily dissolve or emulsify the polymer. Such bases include, for example, organic bases (eg, alkylamines such as triethylamine, cyclic amines such as morpholine, alkanolamines such as triethanolamine, pyridine, etc.), and inorganic bases (eg, ammonia, alkali metal hydroxides) Such)
And so on. The amount of the acid used is, for example, base / acid group = 0.3 / 1 to 1.5 / 1 based on the total mol of the acid group.
(Molar ratio).

The emulsification of the polymer obtained by the solution polymerization is as follows:
It can be carried out in the presence or absence of an organic solvent. When dissolving or emulsifying and dispersing a polymer in the presence of an organic solvent,
As the organic solvent, a water-soluble organic solvent (for example, an alcohol such as isopropanol) is often used. When the polymer is emulsified in the presence of an organic solvent, the organic solvent may be removed after the emulsification by evaporation or the like, and the emulsion may contain an organic solvent. When the organic solvent is removed before emulsifying the polymer, a low-boiling organic solvent (for example, a ketone such as methyl ethyl ketone) is often used.

When the polymer obtained by solution polymerization is emulsified in the presence of an organic solvent, an additive (eg, an emulsifier, a pH adjuster, an acid, etc.) is added to an organic solution containing the polymer, and then added to water. Can be added to emulsify. In this case, it is preferable that water is gradually added by dropping or the like. The temperature at the time of emulsification is preferably lower, for example, 70 ° C. or lower (eg, 5 to 70 ° C.), and more preferably 50 ° C. or lower (eg, 10 to 50 ° C.).

The removal of the organic solvent after emulsification by adding water is performed, for example, at a temperature of 80 ° C. or lower (eg, about 5 to 80 ° C.) at normal pressure or reduced pressure (eg, 0.0001 to 1 atm). Degree) in many cases.

The average particle size of the polymer particles in the aqueous emulsion thus obtained is in a range that does not impair the dispersion stability, adhesion, etc., for example, 0.01 to 2 μm.
Preferably 0.01-1 μm, more preferably 0.01
To 0.5 μm, still more preferably 0.01 to 0.3
It can be selected from a range of about μm.

The aqueous resin composition of the present invention may be a water-soluble or aqueous emulsion (aqueous polymer emulsion). Such an aqueous resin composition is an aqueous resin composition formed without using a special cross-linking resin such as a cross-linked product of an acrylic silicone oligomer containing a hydrolyzable alkoxysilyl group. Is high. Also, by using this aqueous resin composition,
It is possible to obtain a water-based coating composition which has a low risk of air pollution, poisoning, fire and the like and has good workability.

The aqueous resin composition of the present invention may contain, if necessary, lubricating substances such as fluororesins, silicone resins, organic sulfonate compounds, organic phosphate compounds and organic carboxylate compounds. Antioxidants, UV absorbers,
Various known additives such as a stabilizer such as a heat stabilizer, a radical scavenger, a quencher, an antistatic agent, a plasticizer, a thickener, and a defoamer may be added. Thus, an aqueous coating composition using the aqueous resin composition is prepared.

[0096]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. Example 1 In a 2 liter reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a nitrogen inlet tube and a thermometer, 196.0 parts by weight of isopropyl alcohol (IPA) and IPA were added.
Colloidal silica (Nissan Chemical Industries, Ltd.)
120.0 parts by weight of IPA-ST, SiO ₂ 30% by weight) was added, and azobisisobutyronitrile (AIB) was added with stirring.
N) 0.62 parts by weight was added and dissolved, and the mixture was heated to 80 ° C. Methyl methacrylate (MMA) 131.
81 parts by weight, 58.22 parts by weight of n-butyl acrylate (BA), 9.31 parts by weight of acrylic acid (AA), 3-methacryloxypropyltrimethoxysilane (Nihon Unicar Co., Ltd.)
A-174) 4.67 parts by weight, and mercaptopropyltriethoxysilane (manufactured by Nippon Unicar Co., Ltd., A-1
89) 2.04 parts by weight were mixed, and about 4 parts were added using a dropping funnel.
It was dropped into the reaction vessel over time. After completion of the dropwise addition, 0.25 parts by weight of AIBN as an additional catalyst was dissolved in 25 parts by weight of IPA, and the solution was added dropwise to the reaction vessel, and the reaction was maintained for 2 hours. After completion of the polymerization, 25% aqueous ammonia was added to the reaction vessel in an equimolar amount with the amount of acrylic acid used in the polymerization while stirring, and 705 parts by weight of water was dropped into the reaction vessel over about 2 hours to form an emulsion. After emulsification, the IPA was evaporated using a rotary evaporator to obtain the desired aqueous dispersible resin composition. The nonvolatile content of this water-based dispersible resin composition was 40% by weight.

Example 2 The amount of IPA was 140 parts by weight,
The amount of PA-ST was 200.0 parts by weight.
116.30 parts by weight of MA, 51.37 parts by weight of BA, A
8.22 parts by weight of A, 4.12 parts by weight of A-174
A polymerization reaction and emulsion formation were carried out in the same manner as in Example 1 except that the amount of -189 was changed to 1.80 parts by weight, to obtain an aqueous dispersible resin composition.

Example 3 The amount of IPA was 0 parts by weight,
The amount of A-ST was 400.0 parts by weight, and MM was used as a copolymer component.
77.54 parts by weight of A, 34.24 parts by weight of BA, AA
5.48 parts by weight of A-174, 2.74 parts by weight of A-174,
A polymerization reaction and an emulsion were carried out in the same manner as in Example 1 except that the amount of 189 was changed to 1.20 parts by weight to obtain an aqueous dispersible resin composition.

Example 4 The amount of IPA was 140 parts by weight,
The amount of PA-ST was 200.0 parts by weight.
116.30 parts by weight of MA, 51.37 parts by weight of BA, A
8.22 parts by weight of A, 4.12 parts by weight of A-174
A polymerization reaction and an emulsion were carried out in the same manner as in Example 1 except that the amount of -189 was changed to 5.40 parts by weight, to obtain an aqueous dispersible resin composition.

Example 5 The amount of IPA was 140 parts by weight,
The amount of PA-ST was 200.0 parts by weight.
116.30 parts by weight of MA, 51.37 parts by weight of BA, A
8.22 parts by weight of A, 4.12 parts by weight of A-174
A polymerization reaction and an emulsion were carried out in the same manner as in Example 1 except that the amount of -189 was changed to 9.00 parts by weight to obtain an aqueous dispersible resin composition.

Comparative Example 1 A polymerization reaction and emulsion formation were carried out in the same manner as in Example 4 except that A-189 was not used, to obtain an aqueous resin composition.

Comparative Example 2 A polymerization reaction and an emulsion were carried out in the same manner as in Example 4 except that 1.80 parts by weight of tertiary decyl mercaptan (t-DM) was used in place of A-189. A composition was obtained.

Comparative Example 3 A polymerization reaction and an emulsion were carried out in the same manner as in Example 2 except that A-174 was not used, to obtain an aqueous resin composition.

Comparative Example 4 A polymerization reaction and emulsion formation were carried out in the same manner as in Example 2 except that 12.6 parts by weight of A-189 was used to obtain an aqueous resin composition.

Comparative Example 5 The amount of IPA was 254.8 parts by weight,
The amount of IPA-ST was 36.0 parts by weight.
The amount of MA is 148.09 parts by weight, the amount of BA is 65.41 parts by weight, A
The amount of A is 10.46 parts by weight, the amount of A-174 is 5.25 parts by weight,
A polymerization reaction and emulsion formation were carried out in the same manner as in Example 1 except that the amount of A-189 was changed to 2.29 parts by weight to obtain an aqueous dispersible resin composition.

[Comparative Example 6] The amount of IPA was
The amount of A-ST was 433.0 parts by weight.
71.14 parts by weight of A, 31.42 parts by weight of BA, AA
5.02 parts by weight of A-174, 2.52 parts by weight of A-174,
A polymerization reaction and an emulsion were carried out in the same manner as in Example 1 except that the amount of 189 was changed to 1.10 parts by weight to obtain an aqueous dispersible resin composition. Examples 1 to 5 and Comparative Examples 1 to 6 above
Table 1 summarizes the composition (expressed in parts by weight) of the aqueous resin composition of Example 1.

[0107]

[Table 1]

A mill base was prepared according to the formulation shown in Table 2 below, and was formulated into a paint by blending it with each of the aqueous resin compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 4. Obtained.

[0109]

[Table 2]

(Test Example) The following performance evaluation was performed on the water-based coating composition obtained above. 1. Storage stability The obtained aqueous resin composition was diluted with water to a nonvolatile concentration of 20% by weight, left at room temperature for one week, and examined for the occurrence of sediment. ○: No sediment △: Some sediment ×: Sediment

[0111] 2. Warm water resistance An acrylic resin plate is coated with an aqueous resin composition adjusted to a nonvolatile content of 20% by weight, cured at 105 ° C. for 3 minutes, and dried.
It was immersed in warm water at 0 ° C. for 7 days, and the coating was examined for whitening. ：: no whitening △: partial whitening ×: full whitening

[0112] 3. Accelerated weather resistance A water-based coating composition is spray-coated on an alumite-treated aluminum plate so as to have a thickness of 50 μm, baked at 120 ° C. for 3 minutes, and 180 W with a super xenon weather meter (manufactured by Suga Test Instruments, SX2-75). 2000 hours accelerated weathering test with xenon lamp output of
The gloss retention (%) before and after the 60 ° specular gloss test was determined. The accelerated weather resistance was evaluated by the gloss retention (%).

4. Stain resistance test The above-mentioned test plate was held for one month at an angle of 30 ° southward in Aboshi Ward, Himeji City, Hyogo Prefecture, and evaluated by the brightness difference (ΔL) of the test surface. ：: 0 ≦ ΔL <1 Δ: 1 ≦ ΔL <3 ×: 3 ≦ ΔL Table 3 shows the test results.

[0114]

[Table 3]

From Table 3, all of Examples 1 to 5 are excellent in storage stability, hot water resistance and accelerated weather resistance, and also excellent in stain resistance. On the other hand, in Comparative Examples 1 and 2, although colloidal silica was used, A-189 (compound (E)) was not used, so that the storage stability was poor and the weather resistance was slightly poor. In Comparative Example 4, the amount of A-189 (compound (E)) was too large, and the weather resistance was poor. Comparative Example 5
In this case, the amount of colloidal silica was too small, and the stain resistance was poor. In Comparative Example 6, the amount of colloidal silica was too large,
Poor water resistance, poor storage stability and poor weather resistance. In Comparative Example 3, since A-174 (compound (A)) was not used, the water resistance was very poor, and the weather resistance was also poor.

[0116]

The water-based resin composition of the present invention is very excellent in water resistance, weather resistance and stain resistance, particularly, stain resistance. Therefore, an aqueous coating composition using this aqueous resin composition is suitable for undercoat, overcoat, clear coat, lining, etc. of various materials.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (reference) C08F 230/08 C08F 230/08 F term (reference) 4J002 BC04Y BC08Y BC09Y BC10W BD05Y BD10Y BE04W BF01W BF01Y BF02Y BF04W BG01X BG04Y BG05YX BG07Y BG13X BG13Y BH02X BQ00W BQ00X BQ00Y DJ016 GH00 HA07 4J011 HA03 HB14 NA25 NA36 NB04 PA13 PB40 PC02 PC08 4J038 CB001 CC021 CD001 CE001 PC011 CG141 CG161 CG171 CH03103 0204 PC10 4J100 AB02R AB03R AB04R AB07P AB07Q AC03R AC04R AE09P AE18P AE26P AG02R AG04R AG06R AG15P AG24P AJ01Q AJ02Q AJ08Q AJ09Q AL03R AL04R AL05R AL08P AL08Q AL08R AL09R AL10R AL11R AM15R AM21Q AM21R AP01Q AP16P AP16R AP17P BA02P BA03R BA04R BA05R BA14R BA15P BA16Q BA28P BA31Q BA31R BA32Q BA56Q BA58Q BA71R BA77P BA85P BA85R BB01P BC04R BC43P BC43R CA05 EA07 FA02 FA04 FA19 GC22 GD02

Claims (4)

[Claims] 1. A polymerizable unsaturated monomer having a hydrolyzable silyl group (A) in an amount of 0.5 to 50% by weight and a polymerizable unsaturated monomer having at least one ion-forming group (B) )
1 to 20% by weight and another polymerizable unsaturated monomer (C)
[100- (A)-(B)]% by weight is represented by the amount as SiO ₂ and is 5 to the total polymerizable unsaturated monomer ((A) + (B) + (C)). ~ 100% by weight
Of colloidal silica (D) dispersed in a non-aqueous solvent and 0.1 to 5% by weight of the total polymerizable unsaturated monomer ((A) + (B) + (C)) in one molecule. Compound (E) having at least one hydrolyzable silyl group and mercapto group
, A water-based resin composition obtained by emulsion polymerization by adding water to the obtained resin solution. 2. The aqueous resin composition according to claim 1, which is obtained by removing the polymerization solvent after the emulsion is formed. 3. The aqueous resin composition according to claim 1, wherein the colloidal silica (D) dispersed in the non-aqueous solvent is colloidal silica dispersed in an alcohol. 4. A water-based coating composition using the water-based resin composition according to claim 1.