JP2002235030A - Aqueous coating agent composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous coating agent composition having excellent stability of emulsion when allowed to stand, excellent weather resistance, stain resistance, water resistance, alkali resistance and frostproof of a coating film. SOLUTION: This aqueous coating agent composition is obtained by polymerizing an ethylenic unsaturated monomer (B) and a hydrolyzable silyl group- containing monomer (C) in an aqueous emulsion of an acrylic resin (A) having a crosslinking structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the stability of emulsions on standing, the weather resistance, stain resistance and water resistance of coating films, as well as alkali resistance and frost damage resistance. The present invention relates to a water-based coating composition which is excellent in the presence of an aqueous coating composition, and particularly to a water-based coating composition useful as a coating material for building materials, adhesives and paper.

[0002]

2. Description of the Related Art Resins containing polyalkoxypolysiloxanes, tetraalkoxysilanes, and monomers containing alkoxysilyl groups (hydrolyzable silyl groups), especially acryl-silicone resins, have room temperature curability, It has been used as an adhesive, a binder for paints, and a paper coating agent since it forms a coating film of hardness and has excellent properties such as weather resistance and stain resistance. However, in recent years, in the field of paints and adhesives, attempts have been made to convert resins using organic solvents to water-soluble or water-dispersible types from the viewpoint of pollution control and resource saving.

As such an aqueous resin, for example, Japanese Unexamined Patent Publication No.
No. 73543 discloses a so-called core-shell in which the resin composition of a core and an outer shell is changed in particles forming an emulsion for the purpose of improving long-term storage stability, film-forming properties and water resistance. Type emulsions have been proposed. According to the publication, (a) an alkyl (meth) acrylate, (b) a formula R ¹ SiX ₃ (R ¹ : a monovalent organic group having a polymerizable double bond, X: a C1-4 alkoxyl group). And (c) a copolymerizable component (I) comprising a monomer copolymerizable with the above (a) and (b).
(A) alkyl (meth) acrylate, (B) Formula R ² R ³ _{(3- n)} SiY _n
(R ² : a monovalent organic group having a polymerizable double bond, R ³ : C1
To 4 alkyl groups, Y: a C1 to 4 alkoxyl group,
n: 1 or 2) and (C) a component (II) composed of a monomer copolymerizable with (A) and (B) in a specific ratio in the presence of a reactive surfactant. Discloses an acrylic emulsion formed by emulsion polymerization to form a shell on the surface of a core.

Further, Japanese Patent Application Laid-Open No. 11-80651 discloses that (a) (meth) acrylate, (b) carboxylic acid is used for the purpose of obtaining waterproofness without lowering weather resistance, stain resistance and initial drying property. A copolymer obtained by emulsion polymerization of a monomer mixture containing a group-containing monomer, (c) a polyvinyl compound having at least two or more polymerizable unsaturated groups in one molecule, and (d) another polymerizable unsaturated monomer. Combined (I) is used as a core component, and (e) is added to an aqueous dispersion containing the core component.
A copolymer containing (meth) acrylic acid ester, (f) a carbonyl group-containing monomer, and (g) a monomer mixture containing another polymerizable unsaturated monomer and emulsion-polymerizing the mixture to form a shell component. An aqueous coating composition comprising a polymer dispersion (A) and a hydrazine derivative (B) having at least two or more hydrazide groups or semicarbazide groups in one molecule, and a copolymer (I) and / or Alternatively, there is disclosed a resin characterized by including a specific polysiloxane group-containing monomer in a monomer mixture for producing (II).

The present applicant also discloses Japanese Patent Application Laid-Open No. 2000-53919.
In the publication, the storage stability of the emulsion, the weather resistance of the coating film,
For the purpose of improving stain resistance, water resistance and solvent resistance, polyalkoxypolysiloxane (A), unsaturated monomer (B),
In an aqueous medium containing the emulsifier (C), the oil droplet diameter is 100
A silicon-containing aqueous coating agent has been proposed in which an aqueous emulsion previously emulsified so as to have a thickness of 0 nm or less is polymerized in the presence of a polymerization initiator (D).

[0006]

However, the technique disclosed in Japanese Patent Application Laid-Open No. 8-73543 and Japanese Patent Application Laid-Open No. 11-80665 are not disclosed.
According to JP-A No. 1, although storage stability, weather resistance, and water resistance are improved, alkali resistance is not satisfactory. There is a problem that the alkali component erodes the coating film, swells the coating film, and causes whitening, gloss reduction, cracks and the like. Further, the contamination resistance is not sufficient, and further improvement is desired.

On the other hand, in the technology disclosed in Japanese Patent Application Laid-Open No. 2000-53919, although the storage stability of the emulsion, the weather resistance, stain resistance, water resistance and solvent resistance of the coating film are improved,
As above, the alkali resistance was not sufficient.
Further, in any of the above disclosed technologies, when the coating film hardness is increased in order to impart weather resistance and stain resistance, there is also a problem that frost damage resistance such as generation of cracks due to repeated heating and cooling conditions is impaired. .

Under such circumstances, the present invention provides an aqueous coating agent having excellent storage stability of the emulsion, excellent weather resistance, stain resistance, and water resistance of the coating film, and excellent alkali resistance and frost damage resistance. It is intended to provide a composition.

[0009]

Means for Solving the Problems However, the inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, have found that an aqueous ethylenically unsaturated monomer (A) having an acrylic resin (A) having a crosslinked structure can be obtained. The aqueous coating composition obtained by polymerizing the monomer (B) and the hydrolyzable silyl group-containing monomer (C) was found to meet the above-mentioned object, and thus completed the present invention. In the present invention, the hydrolyzable silyl group-containing monomer (C) is particularly preferably a trialkoxysilyl group-containing monomer.

According to the present invention, an aqueous emulsion of an acrylic resin (A) having a crosslinked structure is obtained by polymerizing an acrylic monomer (D) and a crosslinkable monomer (E). It is preferable that the gel fraction of the aqueous emulsion of the acrylic resin (A) having a crosslinked structure is 30% or more, and in particular, the acrylic resin (A) having a crosslinked structure
It is preferred that the aqueous emulsion of (1) further contains tetraalkoxysilane and / or a partially hydrolyzed condensate (F) thereof.

Further, in the present invention, the aqueous emulsion of the acrylic resin (A) having a crosslinked structure may be an acrylic monomer (D) and a crosslinkable monomer (E) or an acrylic monomer (D). ), A crosslinkable monomer (E) and a tetraalkoxysilane and / or a partially hydrolyzed condensate thereof (F)
In an aqueous medium, in the presence of an emulsifier (G), an aqueous emulsion obtained by previously emulsifying the oil droplets to have a diameter of 1000 nm or less in the presence of a polymerization initiator (H). Sometimes, the effect of the present invention is remarkably exhibited. In addition, it is preferable that a hydrolysis inhibitor (I) is further added during the polymerization.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The aqueous emulsion of the acrylic resin (A) having a crosslinked structure used in the present invention is not particularly limited as long as it contains the acrylic resin (A) having a crosslinked structure. Examples thereof include those obtained by polymerizing an acrylic monomer (D) and a crosslinkable monomer (E).

The acrylic monomer (D) includes:
Although not particularly limited, for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate,
Isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate,
Cyclohexyl (meth) acrylate, octyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, acryl chloride, etc., among which methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) acrylate are preferably used.

The crosslinkable monomer (E) is not particularly restricted but includes, for example, polyfunctional monomers containing two or more ethylenically unsaturated groups per molecule, monomers containing hydrolyzable silyl groups, Carboxyl group-containing monomer, hydroxyl group-containing monomer, epoxy group-containing monomer, amide group or methylol group,
Monomers having a functional group such as a monomer containing a carbonyl group and an acetoacetyl group are exemplified.

Specific examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and propylene glycol di (meth) acrylate. (Meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth)
Acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane tetra (meth) acrylate, glycerin methacrylate acrylate, glycerin di (meth) acrylate, tris (Meth) acryloyloxyphosphate, diallyl terephthalate,
Examples include tetraallyloxyethane, divinylbenzene, tri (meth) allyl isocyanurate, diallyl maleate, and pentaerythritol triallyl ether.

The hydrolyzable silyl group-containing monomer includes:
There is no particular limitation as long as the silyl group has at least one alkoxy group. For example, γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (Meth) acryloxypropyltrimethoxysilane, γ- (meth)
Acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ
-(Meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropyldimethylethoxysilane, γ- (meth) acryloxypropyltripropoxysilane, γ -(Meth) acryloxypropylmethyldipropoxysilane, γ- (meth) acryloxypropyltributoxysilane, γ- (meth) acryloxybutyltrimethoxysilane, γ- (meth) acryloxypentyltrimethoxysilane, γ -(Meth) acryloxyhexyltrimethoxysilane, γ- (meth)
Acryloxyhexyltriethoxysilane, γ- (meth) acryloxyoctyltrimethoxysilane, γ-
(Meth) acryloxydecyltrimethoxysilane, γ-
(Meth) acryloxydodecyltrimethoxysilane, γ
-(Meth) acryloxyoctadecyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldipropoxysilane, vinyltri (2-methoxyethoxy) Examples include silane and the like, and one or more kinds are used. Among them, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltri (2-methoxyethoxy) silane and the like are preferable.

Examples of the carboxyl group-containing monomer include acrylic acid, acrylic acid dimer, methacrylic acid, crotonic acid, itaconic acid or its monoester, fumaric acid or its monoester, (anhydride) maleic acid or its monoester, and citraconic acid. Acid, ricinoleic acid, or a salt thereof (amine salt, sodium salt, potassium salt) and the like.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, ethyl carbitol acrylate, tripropylene glycol (meth) acrylate, and 1,4-butylene glycol mono ( Meth) acrylate, 2-hydroxy-3-chloropropyl (meth) acrylate, glycerol mono (meth) acrylate,
2-hydroxyethyl acryloyl phosphate, 4
-Butylhydroxy acrylate, caprolactone-modified 2-hydroxyethyl acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3
-Phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, allyl alcohol and the like.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, allyl glycidyl ether,
N- (4 (2,3-epoxypropoxy) -3,5-dimethylbenzyl) acrylamide, bisphenol A diglycidyl ether mono (meth) acrylate, and the like.

Amide group, methylol group, carbonyl group,
Examples of the monomer containing an acetoacetyl group include acrylamide, methacrylamide, N-methylol (meth) acrylamide, butoxy N-methylolacrylamide, diacetone acrylamide, 2- (acetoacetoxy) ethyl (meth) acrylate, allyl acetoacetate And the like.

In the present invention, if necessary, other monomers such as styrene, α-styrene, vinyl acetate, vinyl propionate, vinyl chloride, ethylene, alkyl vinyl ether, (meth) acrylonitrile, dialkyl itaconate, A dialkyl fumarate, a dialkyl maleate and the like can be used in combination.
These can be used alone or in combination of two or more.

The aqueous emulsion of the acrylic resin (A) having a crosslinked structure of the present invention is obtained by polymerizing the acrylic monomer (D) and the crosslinkable monomer (E).
Further, it is preferable to include a tetraalkoxysilane and / or a partially hydrolyzed condensate (F) thereof from the viewpoint of improving stain resistance and weather resistance.

Preferred examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and the like. Among them, from the viewpoint of easily increasing the hydrolysis rate after polymerization,
Tetramethoxysilane and tetraethoxysilane are preferred.

The partially hydrolyzed condensate of tetraalkoxysilane is obtained by hydrolyzing and condensing the above tetraalkoxysilane, and the degree of condensation can be adjusted by controlling the degree of hydrolysis. The degree of condensation is not particularly limited as long as the condensate maintains a liquid state. Further, it may have a branched structure or a micro gel structure.

The hydrolysis and condensation can be carried out by a known method. For example, a conventional method is carried out by adding a predetermined amount of water to the above tetraalkoxysilane and distilling off by-product alcohol in the presence of an acid or alkali catalyst. And at about room temperature to 100 ° C. By this reaction, the alkoxysilane is hydrolyzed to obtain a further condensed partially hydrolyzed condensate. With respect to such a partially hydrolyzed condensate of tetraalkoxysilane, the use of a partially hydrolyzed condensate having an average degree of condensation of 4 or more has a low odor in the emulsion and a small change over time in the properties of the film when the film is formed. Is preferred.

In producing the aqueous emulsion of the acrylic resin (A) having a crosslinked structure of the present invention, the method is not particularly limited, but the following method is preferable for stably proceeding the polymerization.

That is, the acrylic monomer (D) and the crosslinkable monomer (E), or the acrylic monomer (D), the crosslinkable monomer (E) and the tetraalkoxysilane and / or a part thereof An aqueous emulsion obtained by previously emulsifying the hydrolyzed condensate (F) in an aqueous medium in the presence of the emulsifier (G) so that the diameter of the oil droplets becomes 1000 nm or less, It is a method of polymerizing in the presence.

The emulsifier (G) used above includes:
It has a function of emulsifying a mixture of each component of an acrylic monomer (D), a crosslinkable monomer (E), a tetraalkoxysilane and / or a partially hydrolyzed condensate (F) thereof in an aqueous medium. It is not particularly limited as long as it is a reactive (ionic, non-ionic) surfactant and a non-reactive (ionic, non-ionic) surfactant. Reactive surfactants are preferred in terms of improvement.

The reactive surfactant may be any ionic or nonionic surfactant having radical reactivity with the acrylic monomer (D) and the crosslinkable monomer (E). As the reactive surfactant, for example, the following general formulas (1) to
Those having the structure as in (7) are mentioned.

[0030]

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[0031]

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[0032]

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[0033]

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[0034]

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[0035]

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[0036]

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[Wherein, in the general formulas (1) to (7), R ₁ is an alkyl group, R ₂ is a hydrogen or methyl group, R ₃ is an alkylene group, n is an integer of 1 or more, and m and l are 1 Integer (m + 1 = 3) or more, X is hydrogen, SO ₃ NH ₄ , SO ₃ Na
Is one of ]

Specific examples of the above-mentioned surfactant include Adecaria Soap SE-20N (anionic), Adecaria Soap SE-10N (anionic), and Adecaria Soap N
E-10 (nonionic), Adecaria soap NE-20
(Nonionic), Adecaria soap NE-30 (nonionic), Adecaria soap NE-40 (nonionic),
Adecaria Soap PP-70 (anionic), Adecaria Soap PP-710 (anionic) (all manufactured by Asahi Denka Kogyo KK), Eleminor JS-2 (anionic),
Eleminol RS-30 (anionic) [all, manufactured by Sanyo Chemical Industries, Ltd.], Latemul S-180A (anionic), latemul S-180 (anionic) [all, manufactured by Kao Corporation], Aqualon BC- 05 (anionic), Aqualon BC-10 (anionic), Aqualon BC-
20 (anionic), Aqualon HS-05 (anionic), Aqualon HS-10 (anionic), Aqualon HS-20 (anionic), Aqualon RN-10
(Nonionic), Aqualon RN-20 (nonionic), Aqualon RN-30 (nonionic), Aqualon RN-50 (nonionic), New Frontier S-
510 (anion) (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.),
Commercial products such as Phosphinol TX (anionic) (manufactured by Toho Chemical Industry Co., Ltd.) are exemplified.

The polymerization initiator (H) is not particularly limited, and any of water-soluble and oil-soluble ones can be used. Specifically, alkyl peroxide, t-butyl hydroperoxide, cumene Hydroperoxide,
p-methane hydroperoxide, isobutyl peroxide, lauryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, t-butylcumyl peroxide, benzoyl peroxide, dichlorobenzoyl peroxide, Dicumyl peroxide, di-t-butyl peroxide, 1,1-bis (t-butylperoxy) -3,
3,5-trimethylcyclohexane, 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, di-isobutylperoxydicarbonate, di-2-ethylhexylperoxydicarbonate, t-butylperoxyisobutyrate, etc. Organic peroxides of 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azobisisobutyrate,
2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 4,4 ′ Ammonium (amine) salt of azobis-4-cyanovaleric acid,
2,2′-azobis (2-methylamidooxime) dihydrochloride, 2,2′-azobis (2-methylbutanamidooxime) dihydrochloride tetrahydrate, 2,2′-azobis {2-methyl-N- [ 1,1-
Bis (hydroxymethyl) -2-hydroxyethyl]-
Propionamide {, 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) -propionamide}, various redox catalysts (in this case, oxidizing agents include ammonium persulfate, potassium persulfate, hydrogen peroxide , T-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, p-
Menthane hydroperoxide and the like are used, and as a reducing agent, sodium sulfite, sodium acid sulfite, Rongalit, ascorbic acid and the like are used. ) And the like,
Among them, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2, 2'-azobisisobutyrate and the like.

The polymerization initiator (H) may be added to the polymerization vessel in advance, may be added immediately before the start of the polymerization, or may be added during the polymerization as needed. ,
Further, it may be added in advance to the mixture of (D) and (E) before emulsification, or to the mixture of (D), (E) and (F), or may be added to the emulsion after emulsification. . Upon addition, the polymerization initiator (H) may be separately dissolved in a solvent and added, or the dissolved polymerization initiator (H) may be further added in an emulsified state.

Further, in the production of the aqueous emulsion of the acrylic resin (A), in order to stably carry out the polymerization, a hydrolysis inhibitor (I) is added at the time of the polymerization, and the emulsion may be used as a pre-emulsified liquid. Preferably, the hydrolysis inhibitor (I) is not particularly limited, but is preferably a compound containing an acid functional group and / or an amine imide group neutralized with a base. Examples of the compound include a polymer compound having a dispersing function, a compound having a pH buffering function, a compound having an unsaturated group, and a polymerization initiator, and a polymer compound having a dispersing function is particularly preferable.

First, a polymer compound having a dispersing function will be described. The polymer compound has an acid functional group such as a sulfonic acid group, a carboxyl group, and a phosphoric acid group, and includes a polymer compound in which the functional group is neutralized with a base. A polymer compound obtained by summing is particularly preferred.

The carboxyl group-containing polymer includes (meth) acrylic acid, crotonic acid, fumaric acid, (anhydride) maleic acid, itaconic acid, citraconic acid, and ricinoleic acid (preferably (meth) acrylic acid and fumaric acid). And the like, or obtained by homopolymerizing a monomer having a carboxyl group or copolymerizing with another unsaturated monomer.

The polymer compound preferably contains an amine imide group. The polymer compound is obtained by homopolymerizing an amine imide group-containing monomer or copolymerizing it with another unsaturated monomer. .

The amine imide group-containing monomer includes:
1,1,1-trimethylamine methacrylimide, 1,
1-dimethyl-1-ethylamine methacrylimide,
1,1-dimethyl-1- (2-hydroxypropyl) amine methacrylimide, 1,1-dimethyl-1- (2 ′
-Phenyl-2'-hydroxyethyl) amine methacrylimide, 1,1-dimethyl-1- (2'-hydroxy-3'-phenoxypropyl) amine methacrylimide, 1,1,1-trimethylamine acrylimide, or the following general Examples include monomers represented by the formula (8) and the general formula (9).

[0046]

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[0047]

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Other unsaturated monomers used in the copolymerization include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate and isobutyl (meth) acrylate. Acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, isobornyl (Meth) acrylate, dicyclopentanyl (meth) acrylate, acryl chloride, styrene, α-styrene, vinyl acetate, vinyl propionate, vinyl chloride, ethylene, alkyl vinyl ether,
(Meth) acrylonitrile, dialkyl itaconate, dialkyl fumarate, dialkyl maleate and the like can be used alone or in combination of two or more.

Regarding the molecular weight of the above polymer compound,
Although not particularly limited, a number average molecular weight of 500 to
500,000 is preferred, and more preferably 700-3.
If the molecular weight is less than 000 and the molecular weight is less than 500, the efficiency in the production of the high molecular compound is deteriorated. In addition, the resin composition has a problem that a large amount of coarse particles are generated, which is not preferable.

When the above carboxyl group-containing copolymer is further neutralized with a basic compound, examples of the basic compound include ammonia, N, N-dimethylethanolamine, diethylamine, triethylamine, morpholine, 2-dimethylamino -2-methyl-1-propanol, monoisopropanolamine, monoethanolamine, N, N-diethylethanolamine, 2-amino-
2-methyl-1-propanol, N-methyldiethanol, diisopropanolamine, N-ethyl-diethanolamine, triisopropanolamine, triethanolamine, sodium hydroxide, potassium hydroxide and the like, preferably ammonia, N, N Dimethylethanolamine, diethylamine are used.

In the case where the hydrolysis inhibitor (I) is a compound having a pH buffering function, the compound includes:
There is no particular limitation as long as the reaction system can be maintained at pH 6 to 10. Specifically, sodium hydrogen carbonate, potassium hydrogen carbonate, monosodium phosphate, monopotassium phosphate, disodium phosphate, trisodium phosphate , Sodium acetate, ammonium acetate, sodium formate, ammonium formate and the like. Further, as the above-mentioned hydrolysis inhibitor (I), two or more compounds of the same kind and different kinds can be used in combination.

The method of charging each of the above components is not particularly limited, but a method of dissolving the emulsifier (G) in water and then charging the other components, or a method of charging the acrylic monomer (D) and the crosslinkable monomer The emulsifier (G) was dissolved in the mixture (E) or a mixture of the acrylic monomer (D), the crosslinkable monomer (E), and the tetraalkoxysilane and / or a partially hydrolyzed condensate (F) thereof. After that, a method of charging other components is preferable.

The blending amounts of the acrylic monomer (D) and the crosslinkable monomer (E) are based on the total amount of the acrylic monomer (D) and the crosslinkable monomer (E). The crosslinkable monomer (E) is preferably 0.01 to 10% by weight,
It is more preferably 0.05 to 5% by weight, particularly preferably 0.1 to 3% by weight. If the amount of the crosslinkable monomer (E) is less than 0.01% by weight, it is difficult to achieve both alkali resistance and frost damage resistance of the coating film, and if it exceeds 10% by weight, frost damage resistance is undesirably reduced.

When the tetraalkoxysilane and / or its partially hydrolyzed condensate (F) is used in combination, the amounts of the acrylic monomer (D) and the crosslinkable monomer (E)
Is preferably 1 to 200 parts by weight, more preferably 5 to 100 parts by weight, with respect to 100 parts by weight of the total amount of
Particularly preferred is 10 to 80 parts by weight. If the amount is less than 1 part by weight, no improvement in the stain resistance and weather resistance of the coating film can be expected, and if it exceeds 200 parts by weight, polymerization stability is undesirably reduced.

The mixing amount of the emulsifier (G) may be the total amount of the acrylic monomer (D) and the crosslinkable monomer (E), or the acrylic monomer (D) and the crosslinkable monomer. (E) and a tetraalkoxypolysiloxane and / or a partial hydrolysis condensate thereof (F) in a total amount of 100 parts by weight,
It is preferable that the amount be 1 part by weight, more preferably 1 to 5 parts by weight. If the amount of the emulsifier (G) is less than 0.5 part by weight, sufficient emulsifying performance cannot be maintained and it is difficult to reduce the emulsion to 1 μm or less, making it difficult to carry out polymerization stably. Is undesirably reduced in water resistance.

When the hydrolysis inhibitor (I) is blended, the blending amount is the total amount of the acrylic monomer (D) and the crosslinkable monomer (E) or the acrylic monomer (D). The total amount of the crosslinkable monomer (E) and the tetraalkoxysilane and / or the partially hydrolyzed condensate (F) is preferably 100 parts by weight, more preferably 0.05 to 5 parts by weight. Is 0.1 to 3 parts by weight. If the amount is less than 0.05 part by weight, the polymerization cannot be carried out stably. If the amount exceeds 5 parts by weight, the polymerization stability is lowered, and the water resistance of the coating film is also lowered.

The amount of water used depends on the total amount of the acrylic monomer (D) and the crosslinkable monomer (E), or the acrylic monomer (D), the crosslinkable monomer (E) and Total amount of alkoxysilane and / or partial hydrolysis condensate (F) 1
50 to 400 parts by weight is preferable with respect to 00 parts by weight,
Further, it is preferably 70 to 200 parts by weight, and 50
If the amount is less than part by weight, the emulsion has a high viscosity, and the polymerization stability also decreases.If the amount exceeds 400 parts by weight, the concentration of the obtained coating agent composition decreases and the drying property when forming a coating film decreases. Not preferred.

For emulsification, it is important to use an emulsifying device such as a high-pressure homogenizer or an ultrasonic treatment device.
It is preferably set to 00 kg / cm ² , more preferably 30 to 1000 kg / cm ² .

The temperature at the time of emulsification is not problematic as long as the acrylic monomer (D) and the crosslinkable monomer (E) do not react during emulsification, and usually about 5 to 60 ° C. is appropriate. If heat is generated during emulsification, cool as necessary. When a high-pressure homogenizer is used, treatment of the emulsion (Pas
s) The number of times is preferably about 1 to 5 times. In addition, it is preferable to carry out preliminary emulsification by stirring, shaking or the like before the above emulsification.

The acrylic monomer (D) and the crosslinkable monomer (E), or the acrylic monomer (D), the crosslinkable monomer (E) and the tetraalkoxysilane, And / or emulsifying the partially hydrolyzed condensate (F) in an aqueous medium in the presence of an emulsifier (G).

The particle size of the oil droplet component in the aqueous emulsion is preferably 1000 nm or less, more preferably 50 to 700 nm, and still more preferably 100 to 50 nm.
0 nm. If the particle size of the oil droplet component exceeds 1000 nm, the polymerization stability of the resin composition is undesirably reduced.

After the completion of the above pre-emulsification, the temperature of the aqueous emulsion is raised to initiate the polymerization. For example, (a) the entire amount of the aqueous emulsion is heated as it is to carry out the polymerization; A) A part of the aqueous emulsion is heated to initiate polymerization,
The remaining aqueous emulsion is added dropwise or dividedly to continue the polymerization. (C) Water (a part of emulsifier and, if necessary, a part or all of a hydrolysis inhibitor, a polymerization initiator is charged into a reaction vessel) And then the temperature is raised, and then the aqueous emulsion is added dropwise or added in portions to carry out polymerization. Among them, the method (a) or (c) is most preferable in that the polymerization temperature is easily controlled and the polymerization stability is good, though it depends on the amount of the aqueous emulsion of the acrylic resin (A).

The polymerization initiator (H) is preferably used in an amount of 0.05 to 5 parts by weight based on 100 parts by weight of the total amount of the acrylic monomer (D) and the crosslinkable monomer (E). And more preferably 0.1 to 3 parts by weight. When the amount is less than the above range, the polymerization rate becomes slow and the polymerization tends to be unstable. When the amount exceeds the above range, a crosslinkable polymer is hardly generated, which is not preferable.

The methods (A) to (C) are as follows. As the polymerization condition (a), a range of usually about 40 to 90 ° C. is appropriate, and the reaction is completed in about 1 to 8 hours after the start of the temperature rise. The polymerization conditions in (a) are as follows: 1 to 50% by weight of the reaction solution is polymerized at 40 to 90 ° C. for 0.1 to 4 hours, and the remaining reaction solution is dropped or divided over about 0.5 to 5 hours. Add
If necessary, it is then aged at the same temperature for about 0.5 to 3 hours. As the polymerization conditions for (c), water was charged to 5 to 100% by weight of the reaction solution, the temperature was raised to 40 to 90 ° C., and the reaction solution was added dropwise or dividedly over 0.5 to 5 hours. Then, if necessary, aging at the same temperature for about 0.5 to 3 hours.

The particle size of the resin component of the obtained aqueous emulsion of acrylic resin (A) is 50 to 500 n.
It is preferable that the particles have a particle size of m. The resin concentration of the aqueous emulsion of the acrylic resin (A) is preferably 10 to 65% by weight, and particularly preferably 20 to 55% by weight.

Thus, the aqueous emulsion of the acrylic resin (A) having a crosslinked structure used in the present invention can be obtained. In the present invention, the gel fraction of the aqueous emulsion of the acrylic resin (A) is particularly preferable. Is preferably 30% or more, more preferably 40 to 90%,
Particularly preferably, it is 50 to 80%. If the gel fraction is less than 30%, the alkali resistance and the frost damage resistance of the coating film cannot be achieved at the same time, which is not preferable.

The method for adjusting the gel fraction of the aqueous emulsion of the acrylic resin (A) to 30% or more is not particularly limited, but may be a polyfunctional monomer or a monomer having a self-crosslinkable functional group (hydrolyzable silyl). A group-containing monomer or a methylol group-containing monomer) or a method of copolymerizing a monomer having a functional group such as a carboxyl group, a hydroxyl group, an epoxy group, an amide group, a carbonyl group, or an acetoacetyl group, A method of adding a cross-linking agent that can react with the functional group during and / or after the polymerization may be used.

The gel fraction was measured at 60 ° C., although the film-forming aid was added to the aqueous emulsion of the acrylic resin (A).
Is determined as the ratio (%) of the weight of the remaining coating film after immersion to the weight of the coating film before immersion when the coating film of 30 μm dried for 1 hour at 20 ° C. for 24 hours and dried.

The above acrylic monomer (D), crosslinkable monomer (E), tetraalkoxysilane and / or its partial hydrolyzed condensate (F), emulsifier (G), polymerization initiator (H ), In addition to the hydrolysis inhibitor (I), known chain transfer agents, defoamers, preservatives, rust inhibitors, ultraviolet absorbers, antioxidants, and film-forming agents as long as the effects of the present invention are not impaired. Auxiliaries and the like may be added.

Next, a method for obtaining the aqueous coating composition of the present invention will be described. In the present invention, the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C) are polymerized in the aqueous emulsion of the acrylic resin (A) having a crosslinked structure obtained above. However, the ethylenically unsaturated monomer (B) is not particularly limited, and may be the same as the acrylic monomer (D), for example, methyl (meth) acrylate, Ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-hexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (Meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) Acrylic monomers such as acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and acryl chloride; styrene, α-styrene, vinyl acetate, vinyl propionate, vinyl chloride, ethylene, alkyl vinyl ether, (Meth) acrylonitrile, dialkyl itaconate, dialkyl fumarate, dialkyl maleate, etc., further, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an epoxy group-containing monomer, an amide group, a methylol group, a carbonyl group And a monomer having a functional group such as a monomer having an acetoacetyl group. These can be used alone or in combination of two or more.

Monomers having a functional group such as a carboxyl group-containing monomer, a hydroxyl group-containing monomer, an epoxy group-containing monomer, and a monomer containing an amide group, a methylol group, a carbonyl group, and an acetoacetyl group. And the same as those described above.

Among the above, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and cyclohexyl (meth) are the ethylenically unsaturated monomers (B). ) Acrylates are preferably used.

Further, a hydrolyzable silyl group-containing monomer (C)
Is not particularly limited as long as it has at least one alkoxy group in the silyl group. For example, γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxy Ethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethyl Methoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropyldimethylethoxysilane, γ- (meth) acryloxypropyltripropoxysilane, γ- (meth) acryloxypropylmethyl Dipropoxyoxysilane, γ- (meth) acryloxy Cypropyltributoxysilane, γ- (meth) acryloxybutyltrimethoxysilane, γ- (meth) acryloxypentyltrimethoxysilane, γ- (meth) acryloxyhexyltrimethoxysilane, γ- (meth) acryloxyhexyl Triethoxysilane, γ- (meth) acryloxyoctyltrimethoxysilane, γ- (meth) acryloxydecyltrimethoxysilane, γ- (meth) acryloxydodecyltrimethoxysilane, γ- (meth) acryloxyoctadecyltrimethoxysilane Silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinylmethyldipropoxysilane, vinyltri (2-methoxyethoxy) silane, and the like,
One or more kinds are used.

Among these, preferred are γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane,
(Meth) acryloxypropyltriethoxysilane, γ
-(Meth) acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropyldimethylmethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropyldimethylethoxysilane, γ- (Meth) acryloxybutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, vinyltri (2-
Methoxyethoxy) silane, and particularly preferred are γ- (meth) acryloxyethyltrimethoxysilane, γ- (meth) acryloxyethyltriethoxysilane, γ- (meth) acryloxypropyltrimethoxysilane , Γ- (meth) acryloxypropyltriethoxysilane, γ- (meth) acryloxybutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, etc. trialkoxysilyl groups having three alkoxy groups in the silyl group Contained monomers.

The polymerization of the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C) in the aqueous emulsion of the acrylic resin (A) is not particularly limited. The polymerization of an aqueous emulsion obtained by pre-emulsifying the unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C) in an aqueous emulsion of the acrylic resin (A) can improve the polymerization stability. Preferred from the point.

In obtaining a pre-emulsified aqueous emulsion, it is preferable to use an emulsifier (G ′). Examples of the emulsifier (G ′) include those similar to the above-mentioned emulsifier (G). These are used alone or in combination of two or more.

Further, when polymerizing an aqueous emulsion obtained by pre-emulsifying the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C), a polymerization initiator (H ) Is used. Incidentally, the polymerization initiator (H) may be added in advance in the polymerization vessel, may be added immediately before the start of the polymerization, or may be added during the polymerization as needed. It may be added beforehand to the mixture of (B) and (C) before emulsification, or may be added to the emulsion after emulsification. Upon addition, the polymerization initiator (H) may be separately dissolved in a solvent and added, or the dissolved polymerization initiator (H) may be further added in an emulsified state.

The method of charging each of the above components is not particularly limited, but may be a method of dissolving the emulsifier (G ') in water and then charging the other components, or a method of dissolving the ethylenically unsaturated monomer (B) with water. It is preferable to dissolve the emulsifier (G ') in the mixture of the decomposable silyl group-containing monomer (C) and then charge other components.

The amounts of the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C) are determined based on the amounts of the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer. The amount of the hydrolyzable silyl group-containing monomer (C) is preferably 0.05 to 20% by weight, more preferably 0.1 to 15% by weight, and particularly preferably, based on the total amount of the monomer (C). Is 0.2 to 10% by weight. If the content of the hydrolyzable silyl group-containing monomer (C) is less than 0.05% by weight, the water resistance of the coating film,
Alkali resistance and weather resistance become insufficient, and if it exceeds 20% by weight, polymerization stability decreases and frost damage resistance decreases, which is not preferable.

The amount of the emulsifier (G ′) is 0.3 parts by weight based on 100 parts by weight of the total amount of the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C). The amount is preferably from 7 to 7 parts by weight, more preferably from 0.5 to 5 parts by weight. If the amount is less than 0.3 part by weight, sufficient emulsification performance cannot be maintained, resulting in a decrease in polymerization stability. If the amount exceeds 7 parts by weight, when a coating composition is formed into a coating film, water resistance deteriorates, which is not preferable.

The amount of water used is preferably 30 to 400 parts by weight based on 100 parts by weight of the total amount of the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C).
Further, it is preferably 70 to 200 parts by weight,
If the amount is less than parts by weight, the aqueous emulsion will have a high viscosity, and the polymerization stability will also decrease.If the amount exceeds 400 parts by weight, the concentration of the aqueous coating composition to be formed will be low, and the drying property when forming a coating film will be reduced. Is undesirably reduced.

Next, the polymerization is started by raising the temperature of the aqueous emulsion in the aqueous emulsion of the acrylic resin (A). The amount of the polymerization initiator (H) used depends on the amount of the ethylenically unsaturated polymer. It is preferably 0.03 to 5 parts by weight, particularly preferably 0.05 to 3 parts by weight, based on 100 parts by weight of the total amount of the monomer (B) and the hydrolyzable silyl group-containing monomer (C). .
If the amount is less than the above range, the polymerization rate becomes slow. If the amount exceeds the above range, the solvent resistance and weather resistance may decrease when a coating composition is formed into a coating film, which is not preferable.

In the polymerization, for example, after mixing an aqueous emulsion of the acrylic resin (A) and an aqueous emulsion,
Acrylic resin (A), a method of polymerizing by heating as it is
A part of the aqueous emulsion was mixed into the aqueous emulsion of the above, and the temperature was raised to initiate polymerization, or the remaining aqueous emulsion was dropped or added in its entirety,
Examples thereof include a method in which the polymerization is continued by dividing and continuously dropping, and a method in which the aqueous emulsion is dropped or divided in the presence of the aqueous emulsion of the acrylic resin (A), and the polymerization is performed by continuously dropping, and the like. Not something. Although the polymerization conditions are not particularly limited, it is usually preferable to carry out the polymerization in the range of about 40 to 90 ° C.

After completion of the polymerization, an alkaline solution such as aqueous ammonia is added to adjust the pH to 6 to 8, preferably 7 to 8, to obtain an emulsion useful as an aqueous coating composition. The emulsion preferably has a particle size of 50 to 1000 nm, particularly 100 to 500 nm.

In the aqueous coating composition obtained as described above, the content of the aqueous emulsion of the acrylic resin (A) was 10 to 10% in terms of solid content with respect to the total solid content.
It is preferably 80% by weight, more preferably 20% by weight.
７５75% by weight, particularly preferably 30-70% by weight. When the content is less than 10% by weight, the stain resistance of the coating film becomes insufficient, and when it exceeds 80% by weight, alkali resistance and frost damage resistance decrease, which is not preferable.

The aqueous coating composition of the present invention comprises
Known chain transfer agents, defoamers, preservatives, rust inhibitors, ultraviolet absorbers, antioxidants, film-forming auxiliaries, and the like may be added as long as the effects of the present invention are not impaired. Further, in order to accelerate the curing of the coating film, a curing agent such as an organotin compound such as an organotin compound or an organoaluminum compound may be added, and the curing agent may be added in the form of an emulsion.

Thus, an aqueous coating agent obtained by polymerizing an acrylic monomer (B) and a hydrolyzable silyl group-containing monomer (C) in an aqueous emulsion of an acrylic resin (A) having a crosslinked structure. A composition is obtained, and the aqueous coating agent composition has excellent shelf stability of the emulsion and excellent weather resistance, stain resistance, and water resistance of the coating film, as well as alkali resistance and frost damage resistance (during repeated heating and cooling conditions). And no cracks), and is particularly useful for applications such as building material paints, adhesives, and paper coating agents.

[0088]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below.
In the examples, “%” and “parts” mean on a weight basis unless otherwise specified.

Example 1 [Production of hydrolysis inhibitor (I)] 100 parts of isopropyl alcohol was charged into a flask equipped with a condenser, a thermometer and a stirring blade, and the temperature was raised to 80 ° C. Subsequently, 20 parts of acrylic acid, 33 parts of methyl methacrylate, 47 parts of 2-ethylhexyl acrylate, 1-dodecanethiol 3
Of a azobisisobutyronitrile was added dropwise to the mixture at 80 ° C. for 4 hours.
Polymerized for hours. Next, aqueous ammonia was added with stirring to adjust the pH to 7.5 to obtain a 27% water-isopropyl alcohol solution of the hydrolysis inhibitor (I).

[First-stage polymerization (production of aqueous emulsion of acrylic resin (A))] 74.5 parts of water, emulsifier (G)
(Made by Asahi Denka Co., Ltd., “Adekaria Soap SE-10”
N ") of 1.8 parts and 2.6 parts of the above-mentioned hydrolysis inhibitor (I) (resin content 27%), then 20.5 parts of methyl methacrylate (D) and n-butyl acrylate (D) 1
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 parts, ethyl silicate (F) (Colcoat Co., Ltd.)
, "ES-48"), 24.2 parts of a mixture was added, and the mixture was stirred and mixed to perform preliminary emulsification. The pre-emulsion was subjected to a pressure of 300 kg / c with a high-pressure homogenizer (manufactured by GAULIN).
The mixture was subjected to a ² Pass treatment at m ² and ordinary temperature to prepare 153.4 parts of an emulsion having oil droplets having a diameter of 170 nm.

On the other hand, an emulsifier (G) (Adecaria Soap SE-10N, manufactured by Asahi Denka Co., Ltd.) was added to 2 parts of water.
5 parts were dissolved. Separately, 0.5 part of 2,2′-azobis 2,4-dimethylvaleronitrile was dissolved in 3.0 parts of a film-forming aid (“Dowanol DPNB” manufactured by Dow Chemical Company),
The two liquids were mixed and stirred to prepare 5.7 parts of an emulsion of a polymerization initiator.

Then, 24.3 parts of water, 61.78 parts of a mixture of 36.8 parts of the above-mentioned monomer emulsion and 0.68 part of polymerization initiator emulsion were charged into the polymerization vessel, and the inside of the polymerization vessel was stirred while stirring. It was replaced with nitrogen. Next, after the temperature was raised to 60 ° C., polymerization was performed for 0.5 hour, and the remaining emulsion (monomer emulsion 116.
6 parts and 2.15 parts of a polymerization initiator emulsion)
The polymerization was carried out by dropping over a period of time. After completion of the dropwise addition, polymerization was continued at 60 ° C. for 1 hour to obtain 183.4 parts of an aqueous emulsion of an acrylic resin (A) (resin content: 40%). To the obtained aqueous emulsion of acrylic resin (A), 5% of a film-forming aid (“Dowanol DPNB”, manufactured by Dow Chemical Company) was added.
It was added and the gel fraction was measured, and it was 70%.

[Second Stage Polymerization (Production of Aqueous Coating Composition)] Next, "Adecaria Soap SE-10N" and "Adekaria Soap SE-10N" manufactured by Asahi Denka Co., Ltd. were used as emulsifiers (G ') in 24.2 parts of water. Adecaria Soap NE-10 "was dissolved in 0.2 parts each, and then methyl methacrylate (B) 25.6 was dissolved.
Parts, n-butyl acrylate (B) 12.9 parts, cyclohexyl methacrylate (B) 10.0 parts, γ-methacryloxypropyl trimethoxysilane (C) 1.5 parts,
A mixture of 0.03 parts of 1-dodecanethiol was added, stirred and mixed to carry out preliminary emulsification, and then mixed with 2.83 parts of a polymerization initiator emulsion prepared in the same manner as described above. The mixed solution was mixed with the above-mentioned aqueous emulsion of acrylic resin (A) 183.4.
The polymerization was carried out by dropping at 60 ° C. over 1.5 hours while dripping into the part. After the completion of the dropwise addition, the polymerization was further continued for 2 hours. After cooling, the pH was adjusted to 8.0 with 5% aqueous ammonia to obtain an emulsion (aqueous coating agent composition). The following evaluation was performed on the emulsion.

(Particle size and average particle size of oil droplet component of aqueous emulsion of acrylic resin (A)) The particle size of the oil droplet component after emulsification and the average particle size of the emulsion after emulsion polymerization were determined by laser light It was measured with a scattering particle size analyzer DLS-700.

(Non-volatile content) The non-volatile content was measured under the conditions in accordance with JIS K6828.

(Viscosity) The viscosity was measured at 25 ° C. using a rotational viscometer and conditions according to JIS K7117.

(Amount of coarse particles)
The mixture was filtered through a 0-mesh wire gauze, and the residue was dried at 105 ° C. for 1 hour.
Indicated by weight to g.

(Stability during Storage) The obtained emulsion was allowed to stand at room temperature for 3 months, and the state was visually observed, and evaluated as follows. ○ ・ ・ ・ No change △ ・ ・ ・ Slight viscosity increase × ・ ・ ・ Viscosity increase or gelation

(Hardness) The pencil hardness according to JIS K 5400 was measured.

(Weather resistance) A film-forming aid (“Dowanol DPNB”, manufactured by Dow Chemical Co., Ltd.) was added to the emulsion at a concentration of 7% with respect to the emulsion, and allowed to stand for 1 day. 30 μm dry film thickness on slate plate
Apply with an applicator so that
After drying for 1 minute, the film was exposed outdoors for 9 months, and the state of the coating film was visually observed and evaluated as follows. A: It was a glossy transparent film.・ ・ ・: The degree of gloss was slightly reduced, and the coating state was good. Δ: A decrease in gloss and destruction of the coating film were observed. ×: Significant decrease in gloss and destruction of coating (whitening,
Cracks) were seen.

(Stain resistance) A film-forming aid ("Dowanol DPNB", manufactured by Dow Chemical Co., Ltd.) was added to the obtained emulsion in an amount of 7% with respect to the emulsion, and allowed to stand for 1 day. 30μ dry film thickness on the slate plate
m with an applicator so that the
After drying for 0 minutes, outdoor exposure was performed for 9 months, and the rain streaks of the coating film were visually observed and evaluated as follows. A: Almost no rain streak was observed. ○: Rain lines were slightly observed in some areas. Δ: Rain lines were observed in some places. X: Rain streaks were clearly observed on the entire surface.

(Water resistance) A film forming aid ("Dowanol DPNB", manufactured by Dow Chemical Co., Ltd.) was added to the obtained emulsion at a concentration of 7% with respect to the emulsion. 30 μm dry film thickness on slate plate
Apply with an applicator so that
After drying for minutes, the surface condition after immersion in distilled water for 24 hours was visually observed and evaluated as follows. A: No whitening or swelling was observed.・ ・ ・: Slight whitening was observed, but no swelling was observed. Δ: Whitening and swelling were observed. ×: Whitening and swelling progressed and eluted in some places.

(Alkali resistance) A film forming aid ("Dowanol DPN", manufactured by Dow Chemical Company) was added to the obtained emulsion.
B ") was added to the emulsion in an amount of 7%, and the mixture was allowed to stand for 1 day. Then, the solution was applied to a slate plate previously coated with a sealer using an applicator so as to have a dry film thickness of 30 µm.
After drying at 0 ° C. for 10 minutes, pH 12 alkaline warm water (50
C) for 7 days, the surface condition was visually observed and evaluated as follows. A: No whitening or swelling was observed.・ ・ ・: Slight whitening was observed, but no swelling was observed. Δ: Whitening and swelling were observed. X: Whitening and swelling proceeded, and cracks were observed after drying.

(Frozen damage resistance) A film forming aid ("Dowanol DPNB", manufactured by Dow Chemical Co., Ltd.) was added to the obtained emulsion in an amount of 7% with respect to the emulsion. 30μ dry film thickness on the slate plate
m with an applicator so that the
After drying for 0 minutes, immersing in water (20 ° C.) for 1 hour,
It was left in the air (−20 ° C.) for 2 hours. Thereafter, and were repeated again for a total of 200 cycles. The surface state of the coating film after 200 cycles was observed with a magnifying glass of 20 times and evaluated as follows.・ ・ ・: No crack was generated at all, and no change in the coating film was observed before the test.・ ・ ・: Slight cracks occurred. Δ: Cracks occurred in some places. C: Cracks occurred on the entire coating film.

Example 2 In Example 1, 25.6 parts of methyl methacrylate (B), n-butyl acrylate (B) 1
2.9 parts, cyclohexyl methacrylate (B)
0 parts, 1.5 parts of γ-methacryloxypropyltrimethoxysilane (C), methyl methacrylate (B)
5 parts, 12.5 parts of n-butyl acrylate (B), 10.0 parts of cyclohexyl methacrylate (B), and 3.0 parts of γ-methacryloxypropyltrimethoxysilane (C) (Aqueous coating agent composition) was obtained, and the same evaluation as in Example 1 was performed.

Example 3 In Example 1, 20.5 parts of methyl methacrylate (D), n-butyl acrylate (D) 1
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 part, 20.8 parts of methyl methacrylate (D),
Emulsion (aqueous coating agent composition) except that 19.2 parts of n-butyl acrylate (D), 10.0 parts of cyclohexyl methacrylate (D) and 0.25 part of tripropylene glycol diacrylate (E) were used. ) Was obtained, and the same evaluation as in Example 1 was performed. The aqueous emulsion of the acrylic resin (A) had a gel fraction of 6
It was 0%.

Example 4 In Example 1, 20.5 parts of methyl methacrylate (D), n-butyl acrylate (D) 1
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 part of methyl methacrylate (D) 20.0 parts,
Emulsion (aqueous coating agent composition) except that 18.5 parts of n-butyl acrylate (D), 10.0 parts of cyclohexyl methacrylate (D) and 1.5 parts of tripropylene glycol diacrylate (E) were used. ) Was obtained, and the same evaluation as in Example 1 was performed. The aqueous emulsion of the acrylic resin (A) had a gel fraction of 80.
%Met.

Example 5 In Example 1, 20.5 parts of methyl methacrylate (D), n-butyl acrylate (D) 1
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 part of methyl methacrylate (D) 20.0 parts,
Emulsion (aqueous coating) except that 18.5 parts of n-butyl acrylate (D), 10.0 parts of cyclohexyl methacrylate (D) and 1.5 parts of γ-methacryloxypropyltrimethoxysilane (E) were used. Agent composition) and evaluated in the same manner as in Example 1.
The aqueous emulsion of the acrylic resin (A) had a gel fraction of 75%.

Example 6 In Example 1, ethyl silicate (F) used in the first-stage polymerization (“ES-4” manufactured by Colcoat Co., Ltd.)
8 ") with methyl silicate (F) (manufactured by Mitsubishi Chemical Corporation,
An emulsion (aqueous coating agent composition) was obtained in the same manner as in Example 1, except that “MS-56” was used. The gel fraction of the aqueous emulsion of the acrylic resin (A) was 70%.

Example 7 [First Stage Polymerization (Production of Aqueous Emulsion of Acrylic Resin (A))] In Example 1, 44.06 parts of water and emulsifier (G) (manufactured by Asahi Denka Co., Ltd., “ADEKA Rear soap SE-
10N ") 1.06 parts, the hydrolysis inhibitor (I) (resin content 27%) 2.6 parts, methyl methacrylate (D)
8.3 parts, n-butyl acrylate (D) 7.5 parts, cyclohexyl methacrylate (D) 4.0 parts, tripropylene glycol diacrylate (E) 0.2 parts, ethyl silicate (F) (Colcoat Co., Ltd.) "ES-4
8 ") An emulsion was prepared in the same manner except that the amount was changed to 24.19 parts. Then, 42.0 parts of water and 91.91 parts of the above-mentioned monomer emulsion were charged into the polymerization can, and the polymerization initiator emulsion 1.
Acrylic resin (A) polymerized for 1 hour in the presence of 14 parts
135.05 parts of an aqueous emulsion of
%). The gel fraction of the aqueous emulsion of the acrylic resin (A) was 70%.

[Second Stage Polymerization (Production of Aqueous Coating Composition)] Next, in Example 1, 37.9 parts of water and "Adecaria Soap SE" manufactured by Asahi Denka Co., Ltd. as an emulsifier (G ') were used. -10N "and" Adecaria Soap NE-10 "
In 0.25 parts each of methyl methacrylate (B) 4
0.9 parts, 20.7 parts of n-butyl acrylate (B),
16.0 parts of cyclohexyl methacrylate (B), γ-
1. Methacryloxypropyltrimethoxysilane (C)
Polymerization was carried out in the same manner except that the amount was changed to 4 parts and 0.04 part of 1-dodecanethiol. After the completion of the addition, polymerization was continued for another 2.5 hours. After cooling, the pH was adjusted to 8.0 with 5% aqueous ammonia. , An emulsion (aqueous coating composition) was obtained. The same evaluation as in Example 1 was performed for the obtained emulsion (aqueous coating agent composition).

Example 8 [First Stage Polymerization (Production of Aqueous Emulsion of Acrylic Resin (A))] In Example 1, 94.68 parts of water and emulsifier (G) (manufactured by Asahi Denka Co., Ltd., “ADEKA Rear soap SE-
10N ") 1.68 parts, 2.6 parts of the above-mentioned hydrolysis inhibitor (I) (resin content 27%), methyl methacrylate (D) 2
9.06 parts, n-butyl acrylate (D) 26.59
Parts, cyclohexyl methacrylate (D) 14.0 parts,
Tripropylene glycol diacrylate (E) 0.3
5 parts, ethyl silicate (F) (Colcoat Co., Ltd.
"ES-48") was carried out in the same manner except that 24.19 parts was used to prepare an emulsion. Then, 13.8 water was added to the polymerization can.
, 33.1 parts of the above-mentioned monomer emulsion, and polymerization was carried out for 30 minutes in the presence of 3.9 parts of a polymerization initiator emulsion, and then the remaining monomer emulsion was dropped and polymerized over 2 hours to obtain an acrylic resin ( 190.6 parts of the aqueous emulsion of A) were obtained (resin content 40%). The gel fraction of the aqueous emulsion of the acrylic resin (A) was 70%.

[Second-stage polymerization (production of aqueous coating composition)] Next, in Example 1, 14.24 parts of water,
As an emulsifier (G '), "Adekaria Soap SE-10N" and "Adekaria Soap NE-1" manufactured by Asahi Denka Co., Ltd.
0.10 part, methyl methacrylate (B) 15.3 parts, n-butyl acrylate (B) 7.
8 parts, 6.0 parts of cyclohexyl methacrylate (B),
γ-methacryloxypropyltrimethoxysilane (C)
Except that 0.9 parts and 1-dodecanethiol were changed to 0.02 parts, the polymerization was carried out in the same manner over 1 hour. After the completion of the dropwise addition, the polymerization was continued for another 2 hours. To obtain an emulsion (aqueous coating composition). The same evaluation as in Example 1 was performed for the obtained emulsion (aqueous coating agent composition).

Example 9 In Example 1, 20.5 parts of methyl methacrylate (D) and n-butyl acrylate (D) 1 in the first stage polymerization were used.
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 part of methyl methacrylate (D) 14.9 parts,
An emulsion (aqueous coating composition) was prepared in the same manner except that 24.6 parts of n-butyl acrylate (D), 10.0 parts of cyclohexyl methacrylate (D), and 0.5 part of tripropylene glycol diacrylate (E) were used. ) Was obtained, and the same evaluation as in Example 1 was performed. The gel fraction of the aqueous emulsion of the acrylic resin (A) was 70%.
%Met.

Example 10 In Example 1, ethyl silicate (F) used at the time of the first-stage polymerization (“ES-4” manufactured by Colcoat Co., Ltd.)
8 ") was not used, an emulsion (aqueous coating composition) was obtained, and the same evaluation as in Example 1 was performed. The gel fraction of the aqueous emulsion of the acrylic resin (A) was 50%.

Comparative Example 1 A flask equipped with a condenser, a thermometer, and a stirring blade was charged with 105.8 parts of water and 1.8 parts of an emulsifier (G) (“Adekaria Soap SE-10N” manufactured by Asahi Denka Co., Ltd.). And 2.6 parts of the above-mentioned hydrolysis inhibitor (I) (resin content 27%), and then 51.2 parts of methyl methacrylate, 25.6 parts of n-butyl acrylate, and cyclohexyl methacrylate 2
0.0 parts, γ-methacryloxypropyltrimethoxysilane 3.0 parts, ethyl silicate (Colcoat Co., Ltd.)
A solution prepared by dissolving 0.5 part of azobisisobutyronitrile in a mixture of 24.2 parts and 0.05 part of 1-dodecanethiol) was added thereto, and the mixture was stirred and mixed to perform preliminary emulsification. Was. The pre-emulsified liquid is subjected to a high-pressure homogenizer (GA
(ULIN Co., Ltd.) at a pressure of 100 to 200 kg / cm ² at ordinary temperature for ² Pass to prepare 233.5 parts of an emulsion having oil droplets of 200 nm in diameter.

Next, 23.4 parts of water and the above-mentioned emulsion 2
After 8.02 parts were charged, the temperature was raised to 80 ° C., and initial polymerization was carried out for 30 minutes, and then the remaining emulsion was dropped over 3.5 hours to carry out polymerization. After completion of the dropwise addition, polymerization was further continued at 80 ° C. for 2 hours. After cooling, the pH was adjusted to 8.0 with 5% aqueous ammonia to obtain an emulsion (aqueous coating agent composition).
The same evaluation as in Example 1 was performed. The gel fraction of the emulsion was 90%.

Comparative Example 2 In Example 1, 20.5 parts of methyl methacrylate (D) and n-butyl acrylate (D) 1
9.0 parts, cyclohexyl methacrylate (D)
0 parts, tripropylene glycol diacrylate (E)
0.5 part of methyl methacrylate (D) without using tripropylene glycol diacrylate (E);
9 parts, 19.1 parts of n-butyl acrylate (D) and 10.0 parts of cyclohexyl methacrylate (D) were carried out in the same manner to obtain an emulsion (aqueous coating agent composition). An evaluation was performed. The aqueous emulsion of the acrylic resin (A) had a gel fraction of 2
5%.

Comparative Example 3 An emulsion (aqueous coating composition) was obtained in the same manner as in Example 1 except that γ-methacryloxypropyltrimethoxysilane (C) in the second stage polymerization was not used. The same evaluation as in Example 1 was performed. Tables 1 and 2 show the results of Examples and Comparative Examples.

[Table 1] (A) Oil droplet component Average particle size Non-volatile content Viscosity Particle size of coarse particles (nm) (nm) (%) (mPa · s) (mg / Em100g) Example 1 170 220 45.5 40.0 17 〃 2 170 210 46.4 130.0 20 〃 3 170 220 45.8 40.0 18 〃 4 170 220 45.5 40.0 20 〃 5 170 190 47.4 100.0 4 ６ 6 160 250 46.5 40.0 21 ７ 7 160 200 45.5 60.0 15 ８ 8 180 230 45.8 30.0 20 ９ 9 170 220 45.6 40.0 15 〃 10 250 300 45.5 20.0 15 Comparative Example 1 200 280 46.2 20.0 11 〃 2 170 220 46.0 40.0 15 ３ 3 170 210 45.5 50.0 5

[Table 2] Leaving Hardness Weather Resistance Stain Resistance Water Resistance Alkali Resistance Frost Damage Stability Example 1 ○ F ◎ ◎ ◎ ◎ ◎ ◎ ◎ 2 ○ F ◎ ◎ ◎ ◎ ○ ○ 〃 3 ○ F ◎ ◎ ◎ ◎ ◎ ４ 4 ○ F ◎ ◎ ◎ ◎ ◎ ５ 5 ○ F ◎ ◎ ◎ ◎ ○ ６ 6 ○ F ◎ ○ ○ ◎ ◎ 〃 ○ 7 ○ F ◎ ◎ ◎ ◎ ◎ ○ 〃 8 ○ F ◎ ◎ ◎ ○ ◎ 〃 9 ○ F ◎ ◎ ◎ ◎ ◎ 〃 ○ 10 ○ F ○ △ ◎ ◎ ◎ Comparative Example 1 ○ H ○ ◎ ○ × △ 〃 2 ○ F ○ ○ ○ △ ○ 〃 3 ○ F △ △ △ × ○

[0122]

The aqueous coating composition of the present invention comprises:
Since the ethylenically unsaturated monomer (B) and the hydrolyzable silyl group-containing monomer (C) are polymerized in an aqueous emulsion of an acrylic resin (A) having a cross-linked structure, the emulsion is left standing. It has excellent resistance, weather resistance, stain resistance and water resistance of the coating film, and also has excellent effects on alkali resistance and frost damage resistance (no cracks generated even under repeated heating and cooling conditions). It is useful for applications such as building material paints, adhesives, and paper coating agents.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J038 CC021 CC022 CC071 CC072 CE051 CE052 CF021 CF022 CF071 CF072 CG121 CG122 CG141 CG142 CH031 CH032 CH041 CH042 CH051 CH052 CH071 CH072 DL021 DL022 GA03 GA04 GA06 GA07 NA09 PB05 PC03 PC04 PC06 PC10

Claims (9)

[Claims] 1. An acrylic resin (A) having a crosslinked structure
An aqueous coating composition characterized by polymerizing an ethylenically unsaturated monomer (B) and a hydrolyzable silyl group-containing monomer (C) in an aqueous emulsion of (1). 2. A hydrolyzable silyl group-containing monomer (C).
Is a trialkoxysilyl group-containing monomer. 3. An acrylic resin (A) having a crosslinked structure
Is obtained by polymerizing an acrylic monomer (D) and a crosslinkable monomer (E). The aqueous coating composition according to claim 1, wherein 4. An acrylic resin (A) having a crosslinked structure
The aqueous coating composition according to claim 1 or 3, wherein the gel fraction of the aqueous emulsion is 30% or more. 5. An acrylic resin (A) having a crosslinked structure
5. The aqueous coating composition according to claim 1, wherein the aqueous emulsion further comprises tetraalkoxysilane and / or a partially hydrolyzed condensate thereof (F). 6. An acrylic resin (A) having a crosslinked structure
Is an acrylic monomer (D) and a crosslinkable monomer (E), or an acrylic monomer (D), a crosslinkable monomer (E), a tetraalkoxysilane and / or a part thereof. An aqueous emulsion obtained by previously emulsifying the hydrolyzed condensate (F) in an aqueous medium in the presence of the emulsifier (G) so that the diameter of the oil droplets becomes 1000 nm or less, 6. The aqueous coating composition according to claim 1, which is polymerized in the presence. 7. The method according to claim 1, wherein the polymerization inhibitor further comprises a hydrolysis inhibitor (I).
The coating composition according to claim 6, wherein the composition is added. 8. The coating composition according to claim 6, wherein the emulsifier (G) is a reactive surfactant. 9. An acrylic resin (A) having a crosslinked structure
The aqueous coating composition according to any one of claims 1 to 8, wherein the content of the aqueous emulsion is 10 to 80% by weight in terms of solid content based on the total solid content.