JPH0931401A - Nonstaining coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonstaining coating composition capable of giving a coating having no coating cracks and high surface hardness and capable of obtaining surface hydrophilicity just after coating formation by allowing to contain each of a specific acrylsilicone resin, an alkoxysilane compound and an organosilicate. SOLUTION: This composition is obtained by blending (B) 0.1-20 pts.wt. alkyleneoxide chain-containing alkoxysilane compound based on the solid and (C) 1-30 pts.wt. alkylsilicate of formula II (R3 is a 1-10C alkyl, preferably tetramethylsilicate, etc.) and/or its condensate based on the solid with (A) 100 pts.wt. alkoxysilyl-containing acrylic copolymer resin having a group of formula I [R1 is a 1-10C alkyl; R2 is H, a 1-10C alkyl, aryl, etc.; (a) is 0-2] based on the solid. The component B, e.g. can be obtained by reacting the polyalkyleneoxide chain-containing compound such as polyethylene glycol, etc., with the alkoxysilyl-containing compound such as γ- methacryloxypropyltrimethoxysilane, etc.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is mainly applied to metal, glass, porcelain tile, concrete, siding board,
The present invention relates to a non-contaminating paint composition used for surface finishing of various materials such as extruded plates and plastics.

[0002]

2. Description of the Related Art Conventionally, coating finish has been carried out for the purpose of protecting the skeleton of buildings, civil engineering structures, etc., imparting design characteristics, and improving aesthetics. In particular, with the advent of highly durable paints such as fluorine resin paints, acrylic silicone resin paints or acrylic urethane resin paints in recent years, great progress has been made in the protection of the body. However, with these highly durable paints, in urban areas and urban areas adjacent to factories and main roads, these are caused by air pollution such as exhaust gas,
Contamination resistance against remarkable soot-like or streak-like contamination (rain streak dirt) is further required.

Generally, the stain resistance of a coating film is considered to be a factor in tackiness, surface electrical resistivity, and surface roughness, and various attempts have been made to improve these factors. For example, in Japanese Unexamined Patent Publication No. 6-179790, a hydrophilic agent such as an alkali metal sulfonium salt is mixed with a coating material to reduce the surface resistivity of the coating film, thereby suppressing adhesion of contaminants due to static electricity. Although a method is shown, since sulfonium salts are easily dissolved in water, it elutes from the coating film due to contact with water such as rainfall, forming micro pinholes in the coating film, weather resistance and adhesion of the coating film. It was supposed to deteriorate the general physical properties of the coating film.

Further, Japanese Patent Laid-Open No. 4-370176 discloses that a coating material contains a segmented polymer containing a hydrophilic segment such as a polyalkylene oxide segment and a hydrophobic segment such as a polysiloxane so that the surface of the coating film is hydrophobic. Some of them are expected to have the effect of suppressing the adhesion of pollutants and the effect of cleaning by rainfall, by imparting both hydrophilicity and hydrophilicity at the same time. The hydrophilicity of the coating film surface is represented by, for example, the contact angle of the coating film surface to water as shown in FIG. 1, and the smaller this value is, the more hydrophilic the coating film is. Due to the hydrophilicity of the surface of the coating film, precipitation has the effect of permeating and flowing into the interface between the coating film and the pollutant, and washing away the pollutant with the rain (soil release effect).

The mechanism for making the surface of the coating film hydrophilic is described in the magazine "Surface" Vol. 32 No. 6 (199
4) Introduced by the inventor himself of the above-mentioned Japanese Patent Application Laid-Open No. 4-370176 on page 55 to 61 as "Surface characteristics of silicone polymer as coating material".
It is described as follows that the conversion of hydrophilicity / hydrophobicity of the coating film surface is caused by a morphological change. A silicone macromonomer having a structure in which an acyl urethane bond that is a hydrophilic segment and a siloxane bond that is a hydrophobic segment are adjacent to each other is synthesized, and the hydrophilicity / hydrophobicity of the copolymer (20% by weight of silicone macromonomer) on the film surface is synthesized. The relationship between the orientation of each segment and the atmosphere on the surface of the coating film was examined. As a result, the initial contact angle of water on the surface of the copolymer film was 90 °, but it was 74 ° after the coating film was immersed in water at room temperature for 2 weeks, which was lower than that of the system containing no silicone and the surface was hydrophilic. When it was left to dry for 1 week, the contact angle with water was recovered and it tended to become hydrophobic. The acrylic copolymer film containing no silicone macromonomer as a comparative sample does not exhibit such a phenomenon and can be presumed to be due to the structure of the silicone macromonomer. Also, the surface after drying (DR
ESCA of Y) and surface (WET) immediately after immersion in water for 2 weeks
As a result of the analysis in the depth direction by using N as an element showing the concentration on the surface of the hydrophilic segment and Si as the element of the hydrophobic segment, considering the state of the coating surface layer by the concentration ratio of both, the coating surface It was speculated that when the environment was hydrophobic, the silicone segment was concentrated on the surface, and conversely, when the environment was hydrophilic, the acyl urethane segment was concentrated, resulting in a morphological change. This phenomenon is caused by the localization of the hydrophobic segment with low surface free energy to the surface of the coating film. Thus, when water is present, the morphology changes such that it migrates to the surface of the coating film and is localized. However, as described in the above literature, the morphological change of the coating film surface from hydrophobicity to hydrophilicity is not actually carried out immediately, and rainfall on the coating film surface for a long time to some extent It can gradually become hydrophilic when the contact time with water is long. Furthermore, when there is no rainfall for a certain period of time, that is, when fine weather continues, the surface of the coating film goes backwards to become hydrophobic. Must come in contact with water. As one of the measures to prevent this, there is a method of setting the glass transition point of the coating film forming polymer to be low in order to easily cause the morphology change. This results in the physical attachment of dust that cannot be washed off, which in turn leads to permanent contamination.

On the other hand, Japanese Patent Application No. 6-506632 (International Publication No. WO94 / 06870) discloses that a coating composition is mixed with an organosilicate, and a crosslinking reaction between them causes both hydrophilicity and improvement of hardness of the coating film surface. A method for achieving the above is shown. Generally, in organosilicate, the reaction shown in Chemical formula 3 proceeds, and the silanol group or siloxane bond generated by such reaction becomes a factor of the hydrophilicity of the coating film surface. Therefore, in order to make the surface of the coating film hydrophilic and improve the hardness, the hydrolysis reaction due to the presence of the acid catalyst in the first step is rate-determining.
For these reasons, the above coating requires surface treatment with an acid or the like in order to promote the reaction of the organosilicate. Considering the actual painting on the outer wall of the building, the reaction is thought to proceed due to acid rain, etc., but as before, it is necessary to form a hydrophilic surface, which is necessary to fully exert the soil release effect, after the coating film is formed. Need a long period of time.

[0007]

Embedded image

Further, Japanese Unexamined Patent Publication No. 6-145453 discloses a method in which an acrylic silicon resin is mixed with an organosilicate to obtain a hydrophilic coating film. Acrylic silicone resin has a similar functional group that contributes to curing because it has a hydrolyzable silyl group similar to organosilicate, and therefore has the same curing mechanism.In order to form a coating film, an acid or base is usually mixed as a curing catalyst. It Since these catalysts also allow the reaction of the organosilicate to proceed at the same time, the hydrophilicity of the coating film surface can be obtained relatively quickly. However, as described in JP-A-6-145453, there are many cross-linking sites as compared with an acrylic silicone resin that originally contains a hydrolyzable silyl group in a part of the molecule to adjust the degree of cross-linking of a coating film. If you mix a large amount of organosilicate,
The crosslink density of the coating film becomes too high, the coating film becomes brittle, and a large number of siloxane bonds with strong ionic bond and hydrolyzable by acid or base are introduced.As a result, the chemical resistance of the coating film decreases. As a result, the weather resistance of the coating film decreases. Therefore, in order to improve hydrophilicity, a large amount of organosilicate needs to be blended, but there is a contradiction that the physical properties of the coating film are impaired if a large amount is added.

[0009]

Among the coating films formed by the conventional non-staining type paints, those which require a long period of time to make the surface hydrophilic are those which have a low non-staining property in the early stage after the formation of the coating film. From the low level, rain streaks and the like are generated in a very short time after the completion of the painting work. Originally, the effect of not contaminating non-contamination type paint is to make the effect, and the user who uses it and the client who requests the painting work are expecting the effect. Therefore, even in the early stage after the formation of the coating film, the occurrence of stains, even if temporarily, betrays the expectations of these users and owners, and gives anxiety to the long-term non-staining effect. It will be. Therefore, the problem to be solved by the present invention is that the coating film does not become hydrophilic for the first time by the action that occurs after coating film formation such as rainfall, but immediately after the coating film formation, its surface exhibits hydrophilicity and stains. A composition for a non-contaminating paint that has a soil release effect of washing away a substance, provides a non-contaminating coating film that is strong but does not become brittle due to a specific cross-linking structure, and has good weather resistance and other physical properties of the coating film. To get things.

[0010]

In order to solve such a problem, the inventors of the present invention have earnestly studied to introduce a polyalkylene oxide, which is a hydrophilicity-imparting component, onto the surface of a coating film. The present invention has been completed by finding that it is possible to form a coating film whose surface is hydrophilic from the initial stage by crosslinking a specific alkylene oxide in a specific ratio to the crosslinking of the organosilicate. That is, the non-contaminating coating composition of the present invention,
(A) General formula

Embedded image (B) relative to 100 parts by weight of the solid content of the alkoxysilyl group-containing acrylic copolymer resin containing the group represented by
The alkoxysilane compound containing an alkylene oxide chain has a solid content of 0.1 to 20 parts by weight, and (C) a general formula.

Embedded image 1 to 30 parts by weight of a solid content of an alkyl silicate represented by and / or a condensate thereof, and optionally a catalyst for hydrolysis / condensation of the above alkoxysilyl group. is there.

The alkoxysilyl group-containing acrylic copolymer of component (A) (hereinafter referred to as component (A)), which is one component in the non-contaminating coating composition of the present invention, has the general formula

[Chemical 6] It is a polymer having at least one, preferably two or more alkoxysilyl groups represented by in one molecule. This alkoxysilyl group is the end of the main chain of the component (A) or
It may be contained in the side chain or both. When the number of alkoxysilyl groups in one molecule of the component (A) is less than 1, the solvent resistance of the cured product obtained from the composition of the present invention, that is, the coating film, tends to decrease. In the formula, in the formula, R1 is an alkyl group having 1 to 10 carbon atoms, preferably 1 to 4 carbon atoms, but when the carbon number of R1 exceeds 10,
The reactivity of the alkoxysilyl group decreases, and the reaction also decreases when R1 is other than an alkyl group, for example, a phenyl group or a benzyl group. Specific examples of the alkyl group represented by R 1 include a methyl group, an ethyl group, an n-propyl group,
Examples thereof include isopropyl group, n-butyl group and isobutyl group. R 2 in the above formula is a hydrogen atom or a monovalent hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 4 alkyl groups, aryl groups and aralkyl groups. In the hydrocarbon group represented by R2,
Specific examples of the alkyl group include the same groups as R1, specific examples of the aryl group include a phenyl group, and specific examples of the aralkyl group include a benzyl group. Specific examples of the alkoxysilyl group represented by Chemical Formula 6 include groups contained in the alkoxysil group-containing monomer described later.

The component (A) is excellent in weather resistance, chemical resistance, water resistance and the like because its 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 component (A) is 100 in terms of physical properties such as durability of the cured product obtained from the composition of the present invention.
0-30000 is preferable and 3000-25000 is more preferable.

The component (A) is 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, and 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, acryloylmorpholine, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N-methylol (meth) acrylamide , A phosphoric ester group-containing vinyl compound which is a condensation product of a hydroxyalkyl ester of α, β-ethylenically unsaturated carboxylic acid such as hydroxyalkyl ester of acrylic acid and phosphoric acid or phosphoric ester, urethane Examples thereof include (meth) acrylate containing a bond or a siloxane bond. In addition, the alkoxysilyl group-containing monomer is not particularly limited except that it has a polymerizable double bond, and specific examples thereof include
For example,

[Chemical 7]

Embedded image And the like, and acrylates or methacrylates having an alkoxysilyl group at the terminal via a urethane bond or a siloxane bond are also included. The proportion of the alkoxysilyl group-containing monomer in the component (A) is 5 to 9 from the viewpoint of the curability of the composition and the durability of the coating film.
0% is preferable and 10-70% is more preferable.

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 is derived from a monomer other than the (meth) acryl derivative. It may include a segment. 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, maleic acid, and fumaric acid. Acids, unsaturated carboxylic acids such as itaconic acid, their salts (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.), or those and C1-C20 direct Esters of unsaturated carboxylic acids such as diesters or half-esters with chain or branched alcohols, vinyl acetate,
Vinyl propionate, vinyl ester and allyl compounds such as diallyl phthalate, amino group-containing vinyl compounds 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, butadiene , Other vinyl compounds such as isoprene, fluoroolefin maleimide, N-vinylimidazole, and vinylsulfonic acid.

At least one of these alkoxysilyl group-containing monomers and at least one radically polymerizable monomer are mixed in a suitable non-reactive solvent and copolymerized with a radical polymerization initiator to give an alkoxy compound. A silyl group-containing acrylic copolymer can be obtained. Examples of the radical polymerization initiator include benzoyl peroxide, dichlorobenzoyl peroxide,
2,5-di (peroxybenzoate) hexyne-3,
Examples include perester compounds such as 1,3-bis (t-butylperoxyisopropyl) benzene and t-butylperbenzoate, azo compounds such as azobisisobutyronitrile and dimethylazobutyrate, and organic peroxides. .

Next, the (B) alkylene oxide chain-containing alkoxysilane compound (hereinafter referred to as the (B) component) used in the present invention is a repeating unit of an alkylene oxide group and at least one or more alkoxysilyl groups. Is a compound having The alkylene oxide group repeating unit of the component (B) has 2 to 4 carbon atoms in its alkylene portion, and has 2 to 40 repeating atoms, preferably 2 carbon atoms.
-20. Both ends of the component (B) may be alkoxysilyl groups, one end may be an alkoxysilyl group, and the other end may be another functional group. Examples of such a functional group that can be provided at one terminal include a vinyl group, a hydroxyl group, an epoxy group, an amino group, an isocyanate group, and a mercapto group. The functional group may be bonded to an alkoxysilyl group via a urethane bond, a urea bond, a siloxane bond, an amide bond, or the like.

As the component (B), for example, a compound synthesized by reacting a polyalkylene oxide chain-containing compound with an alkoxysilyl group-containing compound (hereinafter referred to as a coupling agent) can be used. The polyalkylene oxide chain-containing compound preferably has a molecular weight of 150 to 3500, more preferably 200 to 1500. If the molecular weight is less than 150, the hydrophilicity of the cured product will be poor, and the effect of cleaning contaminants due to rainfall will not be obtained. If the molecular weight exceeds 3500, the water resistance and hardness of the cured product will significantly decrease.
Examples of such polyalkylene oxide chain-containing compounds include polyethylene glycol, polyethylene-propylene glycol, polyethylene-tetramethylene glycol, polyethylene glycol diglycidyl ether,
Examples thereof include polypropylene glycol diglycidyl ether, polyoxyethylene diglycolic acid, polyethylene glycol vinyl ether, polyethylene glycol divinyl ether, polyethylene glycol allyl ether, polyethylene glycol diallyl ether and the like. The polyalkylene oxide chain-containing compound can be selected from one kind or a combination of two or more kinds. On the other hand, the coupling agent is, for example, a compound having at least one alkoxysilyl group and other substituents in one molecule. Specific examples of the coupling agent include β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, and N-β. (Aminoethyl) γ-aminopropylmethyldimethoxysilane, N-
β (aminoethyl) γ-aminopropylmethyltrimethoxysilane, γ-aminopropyltrimethoxysilane,
γ-aminopropyltriethoxysilane, isocyanate-functional silane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, and the like.

The synthesis of the component (B) is not particularly limited, but the polyalkylene oxide chain-containing compound and the coupling agent are prepared separately, and for example, for each compound having a polymerizable double bond, a radical polymerization initiator is used. In addition to copolymerization by using, it can be synthesized by a known method such as addition reaction of amino group / epoxy group, isocyanate group / hydroxyl group, or isocyanate group / amino group. It can also be synthesized by a method of ring-opening addition of ethylene oxide to an alkoxysilyl compound having an active hydrogen group such as a primary or secondary amino group. When using a radical polymerization initiator for copolymerization, at least one or more polyalkylene oxide chain-containing compounds having a polymerizable double bond and at least one or more coupling agents are used in a non-reactive suitable solvent. It can be obtained by reacting with. At this time, the radical polymerization initiator used is, for example, benzoyl peroxide, dichlorobenzoyl peroxide, or 2,5-di (peroxybenzoate).
Perester compounds such as hexyne-3,1,3-bis (t-butylperoxyisopropyl) benzene and t-butylperbenzoate, azo compounds such as azobisisobutyronitrile and dimethylazobutyrate, and organic peroxides The thing etc. are mentioned. As the polyalkylene oxide chain-containing compound having a polymerizable double bond,
For example, polyoxyethylene diglycolic acid can be used, and the coupling agent includes γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, etc. Alternatively, they can be used in combination of two or more kinds. In the case of synthesizing by an isocyanate / hydroxyl addition reaction, for example, the polyalkylene oxide chain-containing compound has a compound having a hydroxyl group at the terminal such as polyethylene glycol, and the coupling agent has an isocyanate group such as an isocyanate-containing coupling agent. Compounds are mixed and synthesized. In this synthesis method, it is also possible to use a reaction catalyst such as dibutyltin dilaurate, dibutyltin dimaleate or dioctyltin dimaleate.

The component (B) synthesized in these reactions is obtained by adding a coupling agent to both ends or one end of a polyalkylene oxide chain-containing compound, and these can be used alone or as a mixture of both. .
The blending ratio of the component (B) is such that the resin solid content of the component (A) is 10
The solid content is 0.1 to 20 parts by weight, preferably 0.2 to 10 parts by weight, based on 0 parts by weight. If it is less than 0.1 part by weight, the hydrophilicity of the obtained cured product is not sufficient, and if it exceeds 20 parts by weight, the compatibility with the resin and the water resistance of the cured product are poor.

The general formula (C) used in the present invention,

Embedded image Examples of the alkyl silicate represented by and / or a condensate thereof (hereinafter referred to as the component (C)) include tetramethyl silicate, tetraethyl silicate, tetra-
One or more selected from n-propyl silicate and tetra-i-propyl silicate, and as a condensate,
One or more kinds selected from those obtained by condensing the above tetraalkyl silicate under hydrolysis conditions can be mentioned. In particular, it is preferable to use at least one of tetramethyl silicate and tetraethyl silicate, or a condensate thereof, in terms of the balance between flexibility and denseness of the formed coating film. The degree of condensation of the condensate is preferably 2 to 20, and when the degree of condensation is 20 or more, the viscosity of the condensate rises, the handling becomes inconvenient, and the compatibility with the alkoxysilyl group-containing acrylic resin deteriorates. This results in cloudiness. The component (C) may be mixed with the component (A), or the component (C) may be present in the reaction vessel in advance when the component (A) is synthesized. The latter method is more desirable because it improves compatibility and hydrophilicity.

The mixing ratio of the component (C) is 1 to 30 in terms of solid content based on 100 parts by weight of the resin solid content of the component (A).
Suitable is parts by weight, preferably 10 to 25 parts by weight. If it is less than 1 part by weight, the surface hardness of the cured coating film is not sufficient, causing physical attachment of contaminants and causing permanent contamination. If it exceeds 30 parts by weight, the compatibility with the resin and the cured product. This is because there is a problem that the external appearance is deteriorated and cracks occur.

A catalyst for hydrolysis / condensation of (D) an alkoxysilyl group, which is optionally used in the present invention (hereinafter (D))
Specific examples of the component), dibutyltin dilaurate, dibutyltin dimalate, dioctyltin dilaurate, dioctyltin dimalate, organotin compounds such as tin octylate, phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl. Phosphates such as phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate, propylene oxide, butylene oxide, cyclohexene oxide, glycidyl methacrylate, glycidol, acryl glycidyl ether, γ-glycidoxy Propyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane,
γ-glycidoxypropylmethyldimethoxysilane, an addition reaction product of an epoxy compound with phosphoric acid and / or a monoacidic phosphoric acid ester, maleic acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, citric acid, succinic acid, Examples of the acid compound include phthalic acid, trimetic acid, pyrometic acid, acid anhydrides thereof, and p-toluenesulfonic acid. Also included are mixtures or reactants of these acidic catalysts and amines. For example, hexylamine, N.I. Examples thereof include amines such as N-dimethyldodecylamine and dodecylamine, but organic tin compounds are preferable, and maleate type organic tin compounds are more preferably used because they are particularly excellent in hydrophilicity of the coating film surface at the initial stage of coating film formation. .

The amount of the component (D) used is not particularly limited, but is usually 0.1 to 20 parts by weight per 100 parts by weight of the resin solid content of the components (A), (B) and (C). Parts are suitable, and 0.1 to 10 parts by weight is more preferred. This is because if the amount of component (D) used is less than 0.1 parts by weight, the curability tends to decrease, and if it exceeds 20 parts by weight, the appearance of the coating film tends to decrease.

A dehydrating agent and / or an alkyl alcohol can be added to the non-contaminating paint composition of the present invention, and the long-term storage stability of the non-contaminating paint composition of the present invention can be ensured. It is more preferable to add. Specific examples of the dehydrating agent include, for example, hydrolyzable esters such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthoacetate, methyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and vinyltrimethoxysilane. Compounds. On the other hand, examples of the alkyl alcohol include low molecular weight alcohols such as methanol and ethanol. These dehydrating agents and / or alkyl alcohols are preferably added to the alkoxysilyl group-containing copolymer (A), but they can be added during the polymerization of the component (A) before, after or after the polymerization. . The amount of the dehydrating agent and / or the alkyl alcohol used is not particularly limited, but is preferably 0.5 to 20 parts by weight, more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the resin solid content of the component (A). The combined use of a dehydrating agent and an alkyl alcohol is preferable because a remarkable effect on storage stability can be seen.

In the composition of the present invention, (A), (B),
In addition to the transparent (clear) coating film of the components (C) and (D), a color pigment may be blended to form a colored (enamel) coating film. Examples of such a color pigment include titanium oxide, zinc oxide, Carbon black, ferric oxide,
Inorganic pigments such as lead chromate, molybdate orange, yellow lead, yellow iron oxide, ocher, ultramarine, cobalt green, azo, naphthol, pyrazolone, anthraquinone, perylene, quinacridone, disazo, isoindo Organic pigments such as linone type, benzimidazole type, phthalocyanine type and quinophthalone type can be used.

It is also possible to use extender pigments such as heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, white carbon and diatomaceous earth. In particular, when forming a matte coating, it is optimal to use white carbon or diatomaceous earth, which has the least loss of the non-contaminating effect on the coating surface.
When these inorganic substances are added to the paint, it is preferable to treat the powder surface with a coupling agent or to add the coupling agent to the paint.

Further, additives such as diluents, ultraviolet absorbers, light stabilizers, antioxidants, anti-settling agents, leveling agents, etc., nitrocellulose, cellulose acetate butyrate and other fibrous materials, epoxy resins, etc. There is no problem even if a resin such as a melamine resin, a vinyl chloride resin, a chlorinated polypropylene, a chlorinated rubber, polyvinyl butyral or the like, a filler and the like are added, and known additives for coating materials can be used.

Further, various coatings, in particular, dipping, spraying, brush coating and the like are used to apply the coating composition of the present invention to an object to be coated, and the composition is cured to give an adhesive property to the surface of the object to be coated, It is possible to form a coating film having excellent durability.

[0029]

The hydrophilicity of the surface of the coating film, which occurs in the present invention from the initial stage of coating film formation, is considered to be due to the hydrophilic sites of the constituents. However, when only the surface free energy of the molecule is considered, It is unlikely that hydrophilic sites with large free energy will be distributed on the surface of the coating film from the beginning.
Therefore, although the mechanism of hydrophilicity from the initial stage in the present invention is not clear, it is presumed that hydrophilic sites are extruded on the surface of the coating film due to some peculiarity that occurs only in the constitution of the present invention. Due to these effects, the non-staining effect (soil release effect) of the coating film is exhibited from the initial stage, and further, the entanglement with the crosslinked structure of other components forms a coating film with excellent flexibility and weather resistance. It seems that there is.

[0030]

【Example】

(Synthesis example 1) Polyalkylene oxide chain-containing coupling agent synthesis example (1) In a reaction tank equipped with a heating device, a stirrer, a reflux device, a dehydrator, and a thermometer, polyethylene glycol 200 (average molecular weight 200; Wako Pure Chemical Industries, Ltd.) (Manufactured by Co., Ltd.), 20 parts by weight, and 54.3 parts by weight of Y-9030 (manufactured by Nippon Unicar Co., Ltd.), which is an isocyanate-containing silane, and 0.05 parts by weight of dibutyltin dilaurate are charged, and the mixture is heated to 50 ° C. And reacted for 8 hours to obtain a pale yellow polyethylene oxide chain-containing coupling agent (1). The average molecular weight of the polyethylene oxide chain-containing coupling agent was 800 as measured by gel permeation chromatography (hereinafter referred to as GPC) in terms of polystyrene. (Synthesis example 2) Polyalkylene oxide chain-containing coupling agent synthesis example (2) In a reaction tank equipped with a heating device, a stirrer, a reflux device, a dehydration device, and a thermometer, polyethylene glycol glycidyl ether Epolite 40E (average molecular weight) 170: 100 parts by weight of Kyoeisha Chemical Co., Ltd. and amino group-containing silane A-1100 (manufactured by Nippon Unicar Co., Ltd.) 63.
0 parts by weight and reacted at 50 ° C. for 8 hours to obtain a pale yellow polyethylene oxide chain-containing coupling agent (2). The polyethylene oxide chain-containing coupling agent had an average molecular weight of 980 as measured by GPC in terms of polystyrene.

Example 1 Zemlac (Kanefuchi Chemical Co., Ltd .; average molecular weight 15,000, Tg 30 ° C., resin solid content 50%), which is an alkoxy silyl group-containing acrylic copolymer resin, has a resin solid content of 100. With respect to parts by weight, 6.0 parts by weight of the polyethylene oxide chain-containing coupling agent (1) and methyl silicate 51 (Mitsubishi Chemical Corporation)
(Manufactured; solid content 100%) was mixed in an amount of 1.0 part by weight, and 2.0 parts by weight of dibutyltin dilaurylate was mixed as a curing catalyst to obtain a composition. With respect to this composition, a test body was prepared as follows, and an evaluation test was conducted on the formed coating film. <Test sample preparation method> (a) Applicator coating was applied to three 150 mm × 200 mm × 3 mm transparent glass plates so that the dry film thickness was about 15 μm, and the temperature was 20 ° C. and the humidity was 65%. The test body (1) was cured at 7% for 7 days. (B) SK # 1000 primer (epoxy resin-based primer, manufactured by SK Kaken Co., Ltd.) was spray-coated on three 150 mm × 70 mm × 0.8 mm aluminum plates so that the dry film thickness was about 25 μm, After drying at room temperature of 20 ° C and humidity of 65% for 8 hours, Fussolone enamel [white] (fluorine resin-based enamel coating, manufactured by SK Kaken Co., Ltd.) is sprayed to a dry film thickness of about 20 μm. What was painted and dried at a temperature of 20 ° C. and a humidity of 65% for 16 hours was used as a test material substrate. Next, a test body (2) was prepared by spray-coating the composition on a test body base material so that the dry film thickness was about 15 μm.

<Test Method> (1) Evaluation of Appearance after Curing of Coating Film Using the test body (1), the appearance of the coating film was evaluated according to JIS K5400 7.1 Appearance test of coating film. Evaluation ◯: No abnormalities such as cracks, glossiness and whitening on the coating film ×: Abnormalities such as cracking, glossiness and whitening on the coating film (2) Water resistance evaluation JIS K5400 8.19 using one test body (1) According to the water resistance test, the film was immersed in water at 20 ° C. for 1 week, shaken off the water, and dried for 2 hours at a temperature of 20 ° C. and a humidity of 65% to evaluate the appearance of the coating film. Evaluation ◯: No abnormalities such as cracks, glossiness, and whitening on the coating film ×: Abnormalities such as cracks, glossiness, and whitening on the coating film (3) Acid resistance evaluation Using another test specimen (1), JIS According to the K5400 8.22 acid resistance test, the coating film surface was washed by immersing it in a 5 wt% sulfuric acid aqueous solution at 20 ° C. for 1 week, then dried at 20 ° C. for 2 hours, and the appearance of the coating film was evaluated. Evaluation ○: No abnormalities such as cracks, glossiness, and whitening on the coating film ×: Abnormalities such as cracking, glossiness, and whitening on the coating film (4) Alkali resistance evaluation Using the remaining 1 sheet of the test body (1), According to JIS K5400 8.21 Alkali resistance test, after dipping in 5wt% sodium hydroxide solution at 20 ℃ for 1 week, wash the coated surface with water and
The appearance of the coating film after drying at 0 ° C. for 2 hours was evaluated. Evaluation ◯: No abnormalities such as cracks, glossiness, and whitening on the coating film x: Abnormalities such as cracks, glossiness, and whitening on the coating film (5) Contact angle measurement with water Test using one test piece (2) After making the body, the temperature is 20 ℃,
0.2 cc of deionized water was dropped on the surface of the coating film after drying at a humidity of 65% for 24 hours, 72 hours and 14 days,
Immediately after dropping at 20 ° C., the contact angle after 1 minute was measured with a CA-A type contact angle measuring device manufactured by Kyowa Interface Science Co., Ltd. (6) Contamination resistance Using the remaining one piece of the test body (2), the temperature is 20 ° C and the humidity is 6
5% dried for 1 week facing south in Ibaraki City, Osaka Prefecture 4
Outdoor exposure was carried out at a 5 degree inclination, and the difference in lightness (ΔL value) between the initial and 6 months was measured using a TC-1800 color difference meter manufactured by Tokyo Denshoku Co., Ltd. (7) Resistance to soaking in dirt Using the remaining one piece of the test body (2), the temperature was 20 ° C and the humidity was 6
According to JIS K5400 8.10 Contamination resistance test, 15% by weight carbon black water dispersion paste liquid was dripped on the coating surface to a diameter of 20 mm and a height of 5 mm. Leave for 2 hours in a constant temperature room at ℃. Then, it was washed in running water and the degree of contamination on the surface of the coating film was visually evaluated.

<Evaluation Results> No abnormality was observed in the coating film in the appearance evaluation, water resistance, acid resistance, and alkali resistance evaluation after curing, and the coating film was in a good state. Contact angle to water is 2
4 hours later, 70 ° immediately after dropping, 64 ° after 1 minute,
72 hours after measurement, 62 ° immediately after dropping and 54 after 1 minute
After 14 days, 60 ° immediately after dropping and 54 after 1 minute.
And the contact angles were lower than those of Comparative Examples at the initial time points such as 24 hours and 72 hours. Moreover, in the stain resistance evaluation, the ΔL value was −2.0, and good stain resistance was obtained.

(Examples 2 to 5) A composition was prepared according to Example 1 with the composition shown in Table 1 and evaluated in the same manner as in Example 1. The results shown in Table 2 were obtained. In each case, the contact angle was lower than that of the comparative example at the initial time point such as 24 hours or 72 hours. Also, good stain resistance was obtained in the stain resistance evaluation.

(Comparative Example 1) A composition was prepared by a combination of a usual alkoxysilyl group-containing acrylic resin and a catalyst as shown in Table 1, and the same evaluation as in Example 1 was carried out. The results are as shown in Table 2, and the contact angle was hardly reduced in the initial stage, and good results were not obtained in the stain resistance evaluation.

(Comparative Examples 2 to 3) As in the formulations shown in Table 1, ordinary polyethylene glycol was used in place of the polyethylene oxide chain-containing coupling agent in the Examples to prepare compositions, and the compositions were prepared. When the same evaluation as in Example 1 was carried out, the results shown in Table 2 were obtained, almost no decrease in the contact angle in the initial stage was observed, and no good result was obtained in the evaluation of stain resistance.

(Comparative Example 4) A composition was prepared by using a combination of a usual alkoxysilyl group-containing acrylic resin, a catalyst and methyl silicate as in the formulation shown in Table 1 and evaluated in the same manner as in Example 1. However, as shown in Table 2, the amount of methyl silicate was too large and cracks were generated on the entire surface of the coating film, and other coating film physical property tests could not be performed.

[Table 1]

[Table 2]

[0038]

As described above, the present invention does not make the coating film hydrophilic for the first time by the action that occurs after the coating film is formed, such as rainfall, but makes the surface hydrophilic immediately after the coating film is formed.
A non-contaminating paint composition that provides a non-contaminating type coating film that has the effect of washing away pollutants with rainwater, does not become brittle due to cross-linking, and has good weather resistance and other physical properties of the coating film. Therefore, after the completion of the painting work, the rain line is not soiled in a very short period of time, and the non-polluting type paint originally has an effect of excellent non-polluting property from the initial stage.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a contact angle of a coating film with water.

[Explanation of symbols]

 a Water droplet b Coating film θ Contact angle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hisashi Suzuki 1-25-10 Shimizu, Ibaraki City, Osaka Prefecture SK Kaken Co., Ltd.

Claims (8)

[Claims] (A) General formula (A) With respect to 100 parts by weight of the solid content of the alkoxysilyl group-containing acrylic copolymer resin containing the group represented by
(B) 0.1 to 20 parts by weight of an alkoxysilane compound containing an alkylene oxide chain as a solid content, (C) a general formula: A non-contaminating coating composition, characterized in that the alkyl silicate represented by and / or a condensate thereof is contained in a solid content of 1 to 30 parts by weight. 2. An alkyl silicate represented by Chemical formula 2 of (C) and / or a condensate thereof, wherein R3 is an alkyl group having 1 to 3 carbon atoms.
The composition for non-contaminating paints according to 1. 3. The non-contaminating paint composition according to claim 1 or 2, wherein the alkylene oxide chain of the alkoxysilane compound containing an alkylene oxide chain of (B) is a polyethylene oxide chain. Stuff. 4. The composition for non-contaminating paints according to claim 1, further comprising (D) a catalyst for hydrolysis / condensation of alkoxysilyl groups as a component. Stuff. 5. The non-contaminating paint composition according to claim 4, wherein the catalyst for hydrolysis / condensation of the alkoxysilyl group (D) is an organic tin compound. 6. The non-contaminating paint composition according to claim 4, wherein the catalyst for hydrolysis / condensation of the alkoxysilyl group (D) is a malate-based organotin compound. 7. The component according to claim 1, further comprising (E) a color pigment as a component.
The composition for non-staining paint according to any one of 1. 8. The composition according to claim 1, further comprising (F) an extender pigment as a component.
The composition for a matte non-staining paint according to any one of 1.