JPH10212454A - Hydrophilic hardenable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that has excellent surface hardness and retains hydrophilicity by incorporating a specific alkoxysilyl group-bearing acrylic copolymer with a tetraalkyl silicate, a hardening catalyst and an epoxy resin. SOLUTION: This composition comprises (A) 100 pts.wt. of an acrylic copolymer having an alkoxysilyl group of the formula (R<1> is a 1-10C alkyl; R<2> is a monovalent hydrocarbon selected from the group consisting of H, a 1-10C alkyl, an aryl, an aralkyl; a is 0, 1, 2) and hydroxyl groups, (B) 2-60 pts.wt. of tetraalkyl silicate and/or its condensate, (C) a hardening catalyst, (preferably an acidic hardening catalyst) and (D) an epoxy resin. The component C is preferably used in an amount of 0.1-20 pts.wt. per 100 pts.wt. of the resin solid components of the components A and B. In addition, a dehydrating agent and an alkyl alcohol is preferably used so that the resin composition may be repeatedly used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrophilic curable composition, and mainly relates to metals, ceramics, glass, cement, ceramic moldings, plastics, wood, paper, fibers, and the like.
The present invention relates to a curable composition for a top coat used for building exteriors, home appliances, industrial equipment, and the like.

[0002]

2. Description of the Related Art Conventionally, the surface of industrial products such as ceramic materials, iron and steel, buildings and building materials has been coated with a composition containing acrylic silicone resin.
Thereby, it is possible to impart a design effect to the industrial product, but also a high hardness film is formed on the surface, thereby improving the physical properties such as weather resistance and corrosion resistance of the industrial product. Was.

[0003] At present, there is a social demand for imparting hydrophilicity to the film surface for the following reasons. That is, for example, the pollution of buildings has become a problem mainly in urban areas. However, by improving the wettability of the surface, contaminants attached to the surface can be washed away by rainwater or the like, and the pollution resistance of the building can be improved.

[0004] Hydrophilicity can be imparted by adding a surfactant to the composition, but there is a problem in that it causes a decrease in surface hardness and a problem in maintaining hydrophilicity in long-term outdoor exposure. It was not the way.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydrophilic curable composition which has excellent surface hardness and can maintain hydrophilicity even when exposed to outdoors for a long period of time. To provide.

[0006]

Means for Solving the Problems The hydrophilic curable composition of the present invention is represented by the following general formula (A):

Embedded image (Wherein, R ¹ is an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group, and an aralkyl group; a represents 0, 1 or 2) an acrylic copolymer 1 containing an alkoxysilyl group and a hydroxyl group represented by
00 parts by weight (hereinafter simply referred to as "parts"), (B) tetraalkyl silicate and / or a condensate thereof from 2 to 60 parts by weight.
Part, (C) a curing catalyst, and (D) an epoxy resin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An alkoxysilyl group-containing acrylic copolymer (hereinafter referred to as "alkoxysilyl group-containing acrylic copolymer (A)"), which is one component of the composition of the present invention, is one of the components (A). (Also referred to as "(A) component")
Is a general formula;

Embedded image Is a polymer having at least one, and preferably two or more, alkoxysilyl groups represented by the following formula: This alkoxysilyl group may be contained at the terminal of the main chain of the component (A), may be contained in a side chain, or may be contained in both.

When the number of alkoxysilyl groups in one molecule of the component (A) is less than 1, the solvent resistance of a cured product (for example, a coating film) obtained from the composition of the present invention tends to decrease.

In the above formula, R ¹ is an alkyl group having 1 to 10, preferably 1 to 4 carbon atoms. When the number of carbon atoms exceeds 10, the reactivity of the alkoxysilyl group decreases, and the reactivity also decreases when R ¹ is other than an alkyl group, for example, a phenyl group or a benzyl group.

Specific examples of R ¹ include, for example, a methyl group,
Examples include an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, and an isobutyl group.

In the above formula, R ² is a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of alkyl, aryl and aralkyl groups having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms. .

Specific examples of the alkyl group as R ² include:
The same groups as those of R ¹ can be mentioned, and specific examples of the aryl group include, for example, a phenyl group, and specific examples of the aralkyl group include, for example, a benzyl group.

Specific examples of the alkoxysilyl group represented by the general formula [Formula 4] include, for example, groups contained in an alkoxysilyl group-containing monomer described below.

The alkoxysilyl group-containing acrylic copolymer (A) is excellent in weather resistance, chemical resistance, water resistance, etc. of the cured product since the main chain is substantially composed of an acrylic copolymer chain. Furthermore, in the component (A), if the alkoxysilyl group is bonded to a carbon atom, the obtained cured product will have even more excellent water resistance, and will have excellent alkali resistance, acid resistance and the like.

The number average molecular weight of the alkoxysilyl group-containing acrylic copolymer (A) is from 1,000 to 30, from the viewpoint of physical properties such as durability of a cured product obtained from the composition of the present invention.
000 is preferable, and 3,000 to 25,000 is more preferable.

The component (A) includes, for example, an acrylic monomer such as acrylic acid, methacrylic acid, or a derivative thereof;
It can be obtained by copolymerization with an alkoxysilyl group-containing monomer.

The acrylic monomer is not particularly limited.
Specific examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, cyclohexyl (meth) acrylate, Trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate, (meth) acrylonitrile,
Glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, (meth) acrylamide, α-ethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N, N-dimethylacrylamide, N-methylacrylamide, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-
Hydroxypropyl (meth) acrylate, N-methylol (meth) acrylamide, Toa Gosei Chemical Industry Co., Ltd.
Alonix M-5700, manufactured by Toa Gosei Chemical Industry Co., Ltd.
AS-6, AN-6, AA-
6, AB-6, AK-5, Placel FA-1, Placel FA- manufactured by Daicel Chemical Industries, Ltd.
4, Placel FM-1, Placel FM
-4, a phosphate ester group-containing vinyl that is a condensation product of a hydroxyalkyl ester of an α, β-ethylenically unsaturated carboxylic acid such as a hydroxyalkyl ester of (meth) acrylic acid and a phosphoric acid or a phosphoric ester. And a (meth) acrylate containing a urethane bond or a siloxane bond.

The alkoxysilyl group-containing monomer is not particularly limited except that it has a polymerizable double bond. Specific examples thereof include, for example,

Embedded image

Embedded image And a (meth) acrylate having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond.

The proportion of the alkoxysilyl group-containing monomer in the component (A) is preferably from 5 to 90%, more preferably from 10 to 70%, in view of the curability of the composition and the durability of the coating film.

The component (A) may contain a segment formed by a urethane bond or a siloxane bond in the main chain within a range not exceeding 50%, and may be derived from a monomer other than the (meth) acrylic acid derivative. May be included. The monomer is not limited, and specific examples thereof include aromatic hydrocarbon vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene, and vinyltoluene; Acids, unsaturated carboxylic acids such as itaconic acid, salts thereof (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.), or those having 1 to 20 carbon atoms. Esters of unsaturated carboxylic acids such as diesters or halfesters with chain or branched alcohols; vinyl acetate,
Vinyl esters and allyl compounds such as vinyl propionate and diallyl phthalate; vinyl compounds containing amino groups such as vinyl pyridine and aminoethyl vinyl ether;
Amide group-containing vinyl compounds such as itaconic acid diamide, crotonamide, maleic acid diamide, fumaric acid diamide, N-vinylpyrrolidone; 2-hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, Other vinyl compounds such as butadiene, isoprene, fluoroolefin maleimide, N-vinylimidazole, and vinyl sulfonic acid are included.

The alkoxysilyl group-containing acrylic copolymer (A) can be produced by a method described in, for example, JP-A-54-36395, JP-A-57-36109, and JP-A-58-157810. Although it can be produced, it is most preferable to produce it by a solution polymerization method using an azo radical initiator such as azobisisobutyronitrile from the viewpoint of ease of synthesis.

In this case, n-dodecyl mercaptan, t-dodecyl mercaptan, n-butyl mercaptan, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-mercaptopropylmethyldimethoxysilane may be used, if necessary. ,
γ-mercaptopropylmethyldiethoxysilane, (C
_{H 3 O) 3 Si-S} -S-Si (OCH 3) 3, using a chain transfer agent such as, can be adjusted molecular weight. A chain transfer agent having an alkoxysilyl group in the molecule,
For example, it is preferable to use γ-mercaptopropyltrimethoxysilane because an alkoxysilyl group can be introduced into a terminal of the silyl group-containing acrylic copolymer.

The polymerization solvent used in the solution polymerization method includes hydrocarbons (toluene, xylene, n-hexane, cyclohexane, etc.), acetates (ethyl acetate, butyl acetate, etc.), and ethers (ethyl cellosolve, Butyl cellosolve, cellosolve acetate, etc.),
There is no particular limitation as long as it is a non-reactive solvent such as ketones (methyl ethyl ketone, ethyl acetoacetate, acetylacetone, methyl isobutyl ketone, acetone, etc.).

As the alkoxysilyl group-containing polymer (A), one kind may be used alone, or two or more kinds may be used in combination.

Further, from the viewpoint of compatibility with the tetraalkyl silicate of the component (B) and / or its condensate,
It is desirable to introduce 20 to 50 parts of n-butyl methacrylate as a comonomer in the component (A).

The tetraalkyl silicate and / or condensate thereof as the component (B) used in the present invention can improve the hydrophilicity and hardness of a cured coating film obtained by coating the composition, or can improve Improve the adhesion of materials.

Examples of the tetraalkyl silicate include tetramethyl silicate, tetraethyl silicate, tetra-n-propyl silicate, tetra-i-propyl silicate, tetra-n-butyl silicate and the like.

The condensate of the tetraalkyl silicate can be produced by a known production method in which the above tetraalkyl silicate is condensed under hydrolysis conditions. That is, it can be carried out by adding water to the tetraalkyl silicate and condensing it. As the tetraalkyl silicate condensate, a commercially available product can also be used. Examples of such a condensate include, for example,
MSI51, ESI28, ESI40 (all manufactured by Colcoat Co., Ltd.) and the like.

The above tetraalkyl silicate and / or condensate thereof may be mixed with the component (A),
When synthesizing the component (A), that is, when copolymerizing the alkoxysilyl group-containing monomer and the acrylic monomer, the component (B) may be previously present in the reaction vessel. If the latter method is adopted, compatibility and hydrophilicity are improved.

The mixing ratio of the tetraalkyl silicate is 2 to 60 parts, preferably 5 to 40 parts, per 100 parts of the resin component of the component (A). If the amount is less than 2 parts, the resulting cured product is not sufficiently hydrophilic, and if it exceeds 60 parts, there is a problem that the appearance of the cured product is deteriorated and cracks are easily generated.

Specific examples of the curing catalyst (hereinafter, also referred to as “curing catalyst (C)” or simply “component (C)”) as the component (C) used in the present invention include dibutyltin dilaurate, dibutyltin malate, dioctyl Organotin compounds such as tin laurate, dioctyltin malate, tin octylate, phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl Phosphates, phosphate esters such as didecyl phosphate; propylene oxide,
Butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acrylic glycidyl ether, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane,

Embedded image Cardura E manufactured by Yuka Shell Epoxy Co., Ltd., Epicoat 828, Epicoat 1 manufactured by Yuka Shell Epoxy Co., Ltd.
An addition reaction product of an epoxy compound such as 001 with phosphoric acid and / or a monoacid phosphate, maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, succinic acid, phthalic acid, trimellitic acid, Acidic compounds such as pyromellitic acid, acid anhydrides thereof, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid are exemplified. Also included are mixtures or reactants of these acidic catalysts with amines. For example, hexylamine,
Examples include amines such as N, N-dimethyldodecylamine and dodecylamine.

Of these curing catalysts (C), acidic curing catalysts are desirable, and in particular, acidic phosphoric acid esters, and mixtures or reactants of acidic phosphoric acid esters and amines have high activity and hydrophilicity. The curing catalyst (C) may be used alone or in combination of two or more.

The amount of the component (C) is not particularly limited, but is usually preferably 0.1 to 20 parts, more preferably 0.1 to 20 parts, per 100 parts of the resin solids of the components (A) and (B). ~ 1
0 parts is more preferred. If the amount of the component (C) is less than 0.1 part, the curability tends to decrease, and if it exceeds 20 parts, the appearance of the coating film tends to decrease.

As the epoxy resin of the component (D), a very common epoxy resin can be used. For example, flame-retardant epoxy resins such as epichlorohydrin-bisphenol A type epoxy resin, epichlorohydrin-bisphenol F type epoxy resin, glycidyl ether of tetrabromobisphenol A, novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, and bisphenol A propylene oxide addition Glycidyl ether type epoxy resin, p-
Glycidyl oxybenzoate ether type epoxy resin, m-aminophenol epoxy resin, diaminodiphenylmethane epoxy resin, urethane-modified epoxy resin, various alicyclic epoxy resins, N, N-diglycidylaniline, N, N-diglycidyl- o-toluidine,
Examples include glycidyl ethers of polyhydric alcohols such as triglycidyl isocyanurate, polyalkylene glycol diglycidyl ether and glycerin, and epoxidized products of unsaturated polymers such as hydantoin type epoxy resins and petroleum resins.

It is preferable to use a dehydrating agent and an alkyl alcohol in order to ensure storage stability that does not cause a problem even when used repeatedly over a long period of time.

Specific examples of the dehydrating agent include, for example, methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, methyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, vinyltrimethoxysilane, methylsilicate, Hydrolysable ester compounds such as ethyl silicate are exemplified. Examples of the alkyl alcohol include low molecular weight alcohols such as methanol and ethanol. The dehydrating agent and the alkyl alcohol may be added before the polymerization of the alkoxysilyl group-containing polymer (A), may be added after the polymerization, or may be added during the polymerization.

The amounts of the dehydrating agent and the alkyl alcohol are not particularly limited, but are more preferably 0.5 to 20 parts and 2 to 10 parts based on 100 parts of the resin solids of the components (A) and (B). .

When a dehydrating agent and an alkyl alcohol are used in combination, a remarkable effect on storage stability can be seen.

The composition of the present invention may contain additives such as diluents, pigments (including extender pigments), ultraviolet absorbers, light stabilizers, anti-settling agents, leveling agents, etc., depending on the intended use; nitrocellulose, cellulose acetate Cellulose such as butyrate; resins such as melamine resin, vinyl chloride resin, chlorinated polypropylene, chlorinated rubber, and polyvinyl butyral; and fillers may be added.

After the above composition is applied to the object to be coated by a conventional method such as various coatings, particularly dipping, spraying, and brushing, the composition is usually cured at 30 ° C. or higher to obtain the adhesiveness to the surface of the object to be coated. A coating film having excellent durability and the like can be formed.

[0041]

EXAMPLES Hereinafter, the hydrophilic curable composition of the present invention will be described more specifically based on examples.

Synthesis Example 1 40.4 parts of xylene was charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, nitrogen gas inlet tube and dropping funnel, and the temperature was raised to 110 ° C. while introducing nitrogen gas. rear,
A mixture (a) having the composition shown in the following [Table 1] was dropped at a constant speed over 5 hours by a dropping funnel.

Mixture (a)

[Table 1]

After the addition of the mixture (a) was completed, 0.5 parts of 2,2-azobisisobutyronitrile and 8.1 parts of toluene were added dropwise at a constant speed over 1 hour. After completion of dropping, 2 at 110 ° C
After aging for a period of time, the mixture was cooled, and xylene was added to the resin solution to adjust the solid content to 50%. The number average molecular weight of the obtained resin was 15,200.

Examples 1 and 2 and Comparative Examples 1 and 2 As shown in Table 2 below, the components (B) and (D) were mixed with 100 parts of the resin (A) shown in Synthesis Example 1. did. Using this resin solution, titanium oxide (CR-90 manufactured by Ishihara Sangyo Co., Ltd.) was dispersed so that PWC (the ratio of the pigment to the total solid content) was 40% and the coating solid concentration was 60%, and white enamel was adjusted. . Dispersion was performed for 2 hours with a paint conditioner using glass beads. Dioctyl phosphate and dodecylamine were used as curing catalysts in the white enamel in amounts of 0.1 parts per 100 parts of resin solids.
25 parts were added, and the mixture was diluted with a thinner to a solid concentration of 45%.

[0046]

[Table 2]

This paint was applied to an aluminum plate (A5052P) by air spray so that the dry film thickness was about 30 μm. Thereafter, the coated plate was cured at 23 ° C. for 7 days to form a coating film on the surface of the aluminum plate. The glossiness, Perozos hardness, contact angle with water, and contact angle with water after three months of exposure of the coating film were measured. The results are shown in [Table 3].

[0048]

[Table 3]

[0049]

Industrial Applicability The hydrophilic curable composition of the present invention can form a coating film having excellent surface hardness and maintaining hydrophilicity even when exposed outdoors for a long period of time.

Claims (1)

[Claims] (A) a general formula: (Wherein, R ¹ is an alkyl group having 1 to 10 carbon atoms, R ² is a hydrogen atom or a monovalent hydrocarbon group selected from the group consisting of an alkyl group having 1 to 10 carbon atoms, an aryl group, and an aralkyl group; a represents 0, 1 or 2) an acrylic copolymer 1 containing an alkoxysilyl group and a hydroxyl group represented by
00 parts by weight, (B) tetraalkyl silicate and / or
Or 2 to 60 parts by weight of a condensate thereof, (C) a curing catalyst,
(D) A hydrophilic curable composition comprising an epoxy resin.