JPH10314596A - Corrosionproof film and corrosionproof coating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corrosionproof film and a corrosionproof coating method of superior weather resistance, corrosionproofness and bonding properties and also superior NO removing properties and stainproofness. SOLUTION: A corrosionproof film is formed of a zink-rich paint film layer and a prime layer formed successively in the order on a material to be coated, an intermediate coated layer formed by curing a hydrolytic silicon compound and a pigment and formed on the prime layer and an overlay formed by curing a blend of a hydrolytic silicon compound or a solvent soluble fluorine resin and titanium oxide provided with photocatalyst activities all together at the PWC of 45-85. In the process of the coating method, a zink-rich paint is applied on a material to be coated, and a prime coating material is applied thereon, and then an intermediate coating material in which a hydrolytic decomposing silicon compound is used as a bonding agent is applied, and also a coating material composed of the hydrolytic compound or a solvent soluble fluorine resin in which titanium oxide provided with photocatalyst activities is blended at the PWC of 45-85.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anticorrosion coating and a method for forming an anticorrosion coating for forming a coating layer having a long-term NOx removal property and antifouling property and having excellent weather resistance, corrosion resistance and adhesion. .

[0002]

2. Description of the Related Art Heretofore, the mainstream of anticorrosive coatings on steel structures has long been dominated by oil-based rust preventive coatings. Oil-based rust preventive paint shows good anticorrosion performance in mild corrosive environment,
It has a wide range of application fields due to its wide workability and relatively low cost.

On the other hand, with the development of the polymer chemical industry, various synthetic resins have been developed and applied to anticorrosion paints and the like. For example, some oil-based rust preventive paints, which dry relatively slowly and have poor weather resistance, have been modified with alkyd resin, or long-oil alkyd resin paints have been used in place of oil-based formulated paints. Resin paints are being used.

Further, as a shop primer, a zinc-rich paint containing a large amount of zinc powder in a vehicle for the purpose of protecting iron base by electrochemical action has been developed and used in combination with a synthetic resin paint. It was started.

Particularly in recent years, heavy corrosion-resistant coating systems having high performance and long-term durability have been adopted by using zinc-rich paint or a combination of metal spraying and a thick film type synthetic resin paint in a severe corrosive environment. It has become. As mentioned above,
Rust prevention coating for steel structures is a general coating system using an oil-based primer or zinc-rich primer and a synthetic resin paint, and heavy corrosion protection by metal spraying or coating a thick-film zinc-rich primer and a thick-film synthetic resin paint. The coating system is used in parallel, and is selected according to conditions such as the corrosive environment of the installation location of the structure and the construction conditions.

However, in the conventional coating system as described above, a general coating system using an oil-based primer or a zinc-rich primer and a synthetic resin-based paint is used for 3 to 5 years, and a thick-film type zinc-rich primer and a thick-film type Even in the heavy-duty anticorrosion coating system by applying a resin paint, it was necessary to partially or completely change the coating in 5 to 10 years. This is due to deterioration of gloss due to chalking and discoloration due to deterioration of resin and pigment due to ultraviolet rays, rainwater, etc., and generation of rust, blisters, brushes etc. due to transmission of corrosive substances such as water, oxygen, chlorine ions etc. It is a thing.

On the other hand, as the size of steel structures such as bridges and tanks increases, the cost and man-hours for repainting tend to increase, so that a paint film having corrosion resistance and weather resistance for a long period of time, ie, repainting The demand for long cycle paints has become very strong.

In general, in a corrosion reaction in a painted steel structure in a neutral environment such as in the air, since the oxygen reduction reaction controls the cathode reaction in the corrosion, the oxygen permeation amount of the coating film is a problem. It is believed to be.

In consideration of the dominance of the cathodic reaction in the corrosion due to the oxygen reduction reaction, the critical current density (Imax) corresponding to the corrosion rate of the steel under the coating film is expressed by the following equation.

Imax = Mmax · n · F · = K · Co · nF / d [Mmax: diffusion dissolved oxygen amount, K: oxygen diffusion coefficient d: thickness of the diffusion layer (coating film thickness), n: number of reactive electrons , F: Faraday constant, Co: oxygen concentration]

Therefore, in order to reduce the corrosion rate of steel under the coating film, the film thickness must be made very large or, if the film thickness is constant, the amount of diffused dissolved oxygen or oxygen diffusion coefficient, that is, the amount of oxygen permeation, is reduced. It is necessary to reduce it. It is also necessary to suppress a decrease in film thickness due to chalking or the like for a long time.
If the oxygen permeability of the coating is reduced by half, the corrosion rate of the steel under the coating is also reduced by half, so the oxygen permeability of the coating is a very important factor for the long-term corrosion protection of painted steel structures .

However, alkyd resins and chlorinated rubbers as a vehicle used in the above-mentioned topcoat paint have relatively high oxygen permeability, so that the corrosion of steel under the coating film is accelerated and the coating film is defective. In addition to the above, the resin and pigment are liable to be deteriorated by ultraviolet rays or the like in the above-mentioned top coat, and the gloss and the fading are caused by discoloration, chalking, cracks and the like. Therefore, no long-term anticorrosion property or weather resistance could be expected.

Recently, a silicone resin has been developed as a resin having good weather resistance, and its application to a top coating has been attempted.

However, since the room temperature drying type silicon alkyd resin and silicon acrylic resin have relatively high oxygen permeability, even if the weather resistance of the top coat is slightly improved, the effect of suppressing corrosion of steel under the coat is improved. Was not expected, and the overcoat film was soft, easily stained and scratched, and had the disadvantage that the resin was whitened. In addition, even if the above resin does not deteriorate for a long period of time and has a gloss, the pigment on the surface layer of the coating film fades and changes greatly from the initial color tone, so that it cannot endure long-term use. Furthermore, since the old coating film undergoes crosslinking and the like within the coating film as time passes after coating, the adhesiveness with the repaint is poor, and a defect of peeling between layers may occur. In particular, such defects were often observed when recoating a top coat such as a urethane resin, epoxy resin or tar epoxy resin.

[0015]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and is excellent in weather resistance, corrosion resistance, adhesion, and NOx.
An object of the present invention is to provide an anticorrosion coating and an anticorrosion coating method which are excellent in removability and stain resistance.

[0016]

Means for Solving the Problems The present inventors have conducted research to solve the above-mentioned problems. As a result, the present inventors applied zinc-rich paint on the object to be coated, applied an undercoat paint, and then applied hydrolyzable silicon. By applying an intermediate coating having a compound as a binder, and further applying a coating in which titanium oxide having photocatalytic activity is specifically blended with a hydrolyzable silicon compound or a solvent-soluble fluororesin, No _X removal properties, antifouling properties ,Weatherability,
The knowledge that it is excellent in anticorrosion property and adhesiveness was obtained. The present invention
It has been completed based on such knowledge.

That is, the present invention has a coating layer made of zinc-rich paint on a coating, and has an undercoat layer made of a synthetic resin on the zinc-rich paint coating layer. Above, at least one selected from a hydrolyzable silyl group-containing vinyl copolymer, a hydrolyzate of an organosilane and a partial condensate of a hydrolyzate of an organosilane
Having an intermediate coating layer obtained by curing various kinds of hydrolyzable silicon compounds and pigments, and having a hydrolyzable silyl group-containing vinyl copolymer and a hydrolyzate of an organosilane on the intermediate coating layer And at least one hydrolyzable silicon compound selected from partial condensates of a hydrolyzate of an organosilane or a solvent-soluble fluororesin, and titanium oxide having photocatalytic activity were blended such that the PWC was 45 to 85. An anticorrosion coating having an overcoat layer obtained by curing the product.

Further, the present invention provides (A) a step of applying a zinc-rich paint on an object to be coated and drying at room temperature to form a zinc-rich paint coating; (B) a step of: Apply synthetic resin paint as undercoat paint,
Drying at room temperature to form an undercoat film, (C) a hydrolyzable silyl group-containing vinyl copolymer, a hydrolyzate of organosilane and a hydrolyzate of organosilane on the undercoat film A step of applying, as an intermediate coating, a coating having at least one hydrolyzable silicon compound selected from condensates as a binder, and drying at room temperature to form an intermediate coating, and (D) the intermediate coating. A hydrolyzable silyl group-containing vinyl copolymer, at least one hydrolyzable silicon compound selected from hydrolysates of organosilanes and partial condensates of hydrolysates of organosilanes, or
A solvent-soluble fluororesin and titanium oxide having photocatalytic activity are blended, and the titanium oxide has a PWC of 45 to 8
5 is a process for applying the paint of No. 5 as a top coat and drying at room temperature to form a top coat.

In the present invention, the deterioration of the surrounding environment can be prevented due to the high NOx removal property, and the adhesion of dirt can be suppressed due to the high photoactivity. Has been prevented.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The zinc-rich paint used as a primer in the anticorrosion coating and the coating method of the present invention is 75 to 95% by weight, preferably 8% by weight, in a dry coating.
An organic or inorganic paint containing 0 to 90% by weight of zinc dust.

Examples of the vehicle of the organic zinc-rich paint include a combination of an epoxy resin and a polyamide resin, chlorinated rubber, polystyrene resin, and silicone resin. Examples of the vehicle of the inorganic zinc-rich paint include ethyl silicate and sodium silicate. , Lithium silicate, potassium silicate, ammonium silicate and the like. Particularly preferred vehicles for purposes such as the present invention are epoxy resin-polyamide resin combinations, ethyl silicate, potassium silicate, and lithium silicate.

The synthetic resin paint used in the present invention is preferably, as a color developing agent, an epoxy resin (including tar-modified and urethane-modified), a vinyl resin (including tar-modified and acrylic resin), a chlorinated rubber, At least one kind of synthetic resin selected from polyurethane resins and phenolic resins, commonly used coloring pigments, extenders, sedimentation inhibitors,
It is a paint obtained by kneading a dispersant, a curing agent, a curing accelerator, a diluent, a solvent and the like.

The epoxy resin is a resin having two or more epoxy groups in a molecule and usually used for paint.

The epoxy resin is, for example, a bisphenol type epoxy resin which is generally commercially available under the trade name of Epikote 828, 834, 836, 1001, 1004, DX-255 manufactured by Shell Chemical Co .; Araldite CY-260 manufactured by Dow Chemical Co., Ltd. DER330, 331, and 337 manufactured by Dow Chemical Company; Epicron 800 manufactured by Dainippon Ink and Chemicals, etc .; commercially available as a phenol novolak type epoxy resin. Product name DE manufactured by Dow Chemical Company
N431, 438; Araldite CT-508, a commercial product of Ciba-Geigy as a polyglycol type epoxy resin; DE, a commercial name of Dow Chemical Company
R-732 and 736; as ester type epoxy resins, for example, Epicron 2 (trade name, manufactured by Dainippon Ink Industries, Ltd.)
Examples of the linear aliphatic epoxy resin include epoxidized polybutadiene such as BF-1000 (trade name, manufactured by Nippon Soda Co., Ltd.).

Further, epoxy compounds easily deduced from these resins, and derivatives of the above-mentioned epoxy resins, can also be used, and are included in the technical scope of the present invention.

For example, polyol-type epoxy resins, alicyclic epoxy resins, halogen-containing epoxy resins and the like are included.

The epoxy resin includes natural asphalt,
Asphaltite, asphalt-based pyrobitumen,
Bituminous substances such as tar, coal tar, artificial asphalt and pitch can be mixed.

Further, as the curing agent for the epoxy resin,
Those usually used for paints, such as amine adducts and polyamide resins, can be used.

Examples of the curing agent include Toamide Y-25, 245, 2400, and 2500 manufactured by Fuji Kasei Kogyo Co., Ltd., which are generally commercially available as polyamide resins;
Zenamide 2000, Versamide 115, 125, manufactured by Daiichi General Co., Ltd .; Sunmide 32, manufactured by Sanwa Chemical Co., Ltd.
0, 330, X2000; Epicure 3255, 4255 manufactured by Shell Chemical Co .; Tomide 238, manufactured by Fuji Chemical Co., Ltd. as amine adduct resin; Fuji Cure 202: Adeka Hardener E, manufactured by Asahi Denka Co.
H-531; trade names Sunmide T-100, D-100, and P-10 manufactured by Sanwa Chemical Co., Ltd. as aliphatic polyamines
0; Examples of the heterocyclic diamine derivative include Epomate B-002, C-002, and S-005 manufactured by Ajinomoto Co.

The amount of the curing agent added to the epoxy resin is around the equivalent, that is, 0.7 to the equivalent of the epoxy resin.
It is in the range of about 1.3 equivalents.

Further, a polyisocyanate can be used as a curing agent for the epoxy resin.

The above-mentioned polyisocyanate contains 2 per molecule.
Polyisocyanate having at least two isocyanate groups, for example, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate,
Hexamethylene diisocyanate, decamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene-diisocyanate, 2,6-tolylene-diisocyanate,
1,5-naphthylene-diisocyanate, 4,4 ',
4 "-triphenylmethane-triisocyanate, 4,
4'-diphenylmethane-diisocyanate, 3,3 '
-Dimethyl-4,4'-diphenylene-diisocyanate, m-xylylene-diisocyanate, p-xylylene-diisocyanate, isophorone diisocyanate,
Excess of polyisocyanate such as lysine isocyanate and the above isocyanate compound, for example, ethylene glycol, propylene glycol, 1,3-butylene glycol, neopentyl glycol, 2,2,4-trimethyl-1,3-pentanediol, hexamethylene glycol Diisocyanates having a bifunctional or higher functionality, polyisocyanates having a burette structure, polyisocyanates having an allophanate bond, etc., obtained by an addition reaction with a low molecular polyol such as cyclohexanedimethanol, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, etc. Is mentioned. The mixing ratio of the epoxy resin and the polyisocyanate is preferably in the range of (hydroxyl group in epoxy resin) / (isocyanate group in polyisocyanate) = 1 / 1.3 to 1 / 0.5 (equivalent ratio).

The vinyl resin used in the present invention includes vinyl chloride, vinylidene chloride, vinyl acetate, vinyl propionate, styrene, vinyl toluene, vinyl alcohol, acrylic acid, methacrylic acid, maleic anhydride, and alkyl acrylate. And one or more copolymers of monomers such as methacrylic acid alkyl esters, and examples thereof include vinyl chloride resins, vinyl chloride-vinyl acetate copolymer resins, and acrylic resins.

The chlorinated rubber resin used in the present invention is a chlorinated product of natural rubber and is usually a compound having a chlorine content of 65 to 68%.

The chlorinated rubber can be used by mixing with rosin, coumarone-indene resin, phenol resin, vinyl chloride resin, petroleum resin, nitrile rubber, chloroprene rubber, and alkyd resin.

Further, it is used by mixing with a plasticizer such as paraffin chloride, diphenyl chloride, dioctyl phthalate, tricresyl phosphate and the like.

Further, the polyurethane resin used in the present invention refers to a compound having two or more active hydrogens in a molecule, for example, a polyester polyol, polyether polyol, polyoxypolyol obtained from a polybasic acid and a polyhydric alcohol. This is a composition using alkylene glycol, acrylic polyol, or the like as a main component, and using a polyisocyanate having two or more isocyanate groups in the molecule described above as a curing agent.

The hydrolyzable silicon compound used in the present invention is selected from the group consisting of a hydrolyzable silyl group-containing vinyl copolymer, an organosilane hydrolyzate and a partial condensate of an organosilane hydrolyzate. These are selected and can be used alone or in combination of two or more.

The silyl group-containing vinyl copolymer comprises at least one ethylenically unsaturated monomer having at least one group of the general formula (I):> C = C <;
And at least one silyl group-containing polymer of the formula (I).

RSiX _n R ¹ _(3-n) (II) (wherein, R is a monovalent organic group containing a vinyl group, R ¹ is an alkyl group, an aryl group or an aralkyl group having 1 to 10 carbon atoms) , X is a hydrolyzable group selected from the group consisting of halogen, alkoxy, alkoxyalkoxy, acyloxy, ketoxime, amino, acid amide, aminooxy, mercapto, and alkenyloxy groups, and n is an integer of 1 to 3.)

Examples of the silyl group-containing monomer include:
γ-methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, vinyl-tris (2-methoxyethoxy) silane and the like.

Examples of ethylenically unsaturated monomers suitable for producing the silyl group-containing vinyl copolymer include:
Alkyl acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, butyl methacrylate, 2-methylhexyl methacrylate and lauryl methacrylate; styrene,
Vinyl aromatic hydrocarbons such as vinyltoluene and α-methylstyrene; vinyl halides such as vinyl chloride; vinylidene halides such as vinylidene chloride; conjugated dienes such as butadiene and isoprene; and saturated fatty acids having 1 to 12 carbon atoms. There are vinyl ester, vinyl acetate, vinyl propionate and the like, and these can be used alone or in combination of two or more.

When the silyl group-containing vinyl copolymer of the present invention is produced, the ethylenically unsaturated monomer and the silyl group-containing monomer can be used in any ratio.
The silyl group-containing monomer is preferably used in a ratio of 0.5 to 25 mol%, and the ethylenically unsaturated monomer is preferably used in a ratio of 99.5 to 75 mol%. When producing this copolymer, a conventionally known method can be used. The molecular weight of the silyl group-containing vinyl copolymer is from 3,000 to 1,000,000.
It is preferably set to 0, especially 10,000 to 300,000.

The hydrolyzate of the organosilane used in the present invention is a compound represented by the following formula (III-A), (III-B) or (IV).

[0045] _{^{R 2 Si (OR 3) 3}} (III-A) Si (OR 3) 4 (III-B) R 2 2 Si (OR 3) 2 (IV) ( wherein, R ² is C 1 -C ~ 8 organic groups, R
³ is an alkyl group having 1 to 4 carbon atoms, each R ² ,
R ³ may be the same or different. )

In the present invention, the compounds represented by the general formulas (III-A) and (III-A)
A partially condensed compound of the compound represented by B) or (IV) can be used. In the present invention, the hydrolyzate of the organosilane or a partial condensate thereof is one component that functions as a binder. The polycondensed molecular weight of the partially condensed compound is from 1,000 to 5,000, preferably from 1,500 to 3,000.

When this hydrolyzate or its partial condensate is used, it is preferable to use a solvent solution containing a solid content of 10 to 80% by weight.

Formula (III-A), (III-B) or (IV)
Specific examples of the organic group R ² include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an alkyl group such as an i-butyl group, a γ-chloropropyl group, a vinyl group,
Examples include 3,3,3-trifluoropropyl group, γ-glycidoxypropyl group, γ-methacryloxypropyl group, γ-mercaptopropyl group, phenyl group, and 3,4-epoxycyclohexylethyl group. Further, Specific examples of the alkyl group R ^3, a methyl group, an ethyl group, n- propyl group, i- propyl, n- butyl group, sec- butyl group, and the like tert- butyl group.

Specific examples of the organosilane represented by the general formula (III-A) are as follows: methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n -Propyltrimethoxysilane, n-propyltriethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane Ethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane,
3,3,3-tolufluoropropyltriethoxysilane,
γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyl Triethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane, i-butyltrimethoxysilane, i-butyltriethoxysilane, etc. And particularly preferred are methyltrimethoxysilane and methyltriethoxysilane.

Specific examples of the organosilane (alkyl silicate) represented by the general formula (III-B) include tetramethyl silicate, tetraethyl silicate, tetra-n-propyl silicate, tetra-i-propyl silicate and tetra-silicate. n-butyl silicate, tetra-i-
Butyl silicate, tetra-sec-butyl silicate, and the like. Specific examples of the organosilane (IV) include dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, di-i-propyldimethoxysilane, and di-i-propyldiethoxysilane. , Di-i-propyldimethoxysilane, di-i-propyldiethoxysilane,
Examples include diphenyldimethoxysilane and diphenyldiethoxysilane, and dimethyldimethoxysilane and diethyldiethoxysilane are particularly preferred. In the present invention, these hydrolyzable silicon compounds can be used alone or in combination of two or more.

When the organosilanes of the general formulas (III-A), (III-B) and (IV) are used in combination, the mixing ratio of (III-A) to (III-B) in terms of organosilane ( Weight ratio)
00: 0 to 30 (that is, (III-B) may not be contained in some cases), (III-A) and (III-A) in terms of organosilane.
B) and the mixing ratio (weight ratio) of (IV) to 100:
It is preferably 5 to 150, especially 100: 10 to 120. When the mixing ratio of the organosilane of the general formula (IV) is larger than the above range, the formed coating film is liable to crack, and conversely, when the mixing ratio is smaller than the above range, the curability is reduced and the coating property is reduced. Film hardness tends to decrease.

In the present invention, a hydrolyzate of the organosilane or a partial condensate thereof is used, and water is added to perform the hydrolysis and the partial condensation. The amount of water to be added is generally 0.1 to 1.0 mol, especially 0.15 to 0 mol, per equivalent of the alkoxy group of the organosilane of the general formulas (III-A), (III-B) and (IV). It is preferable to use 0.7 mol. If the number of moles of water is smaller than the above range, the storage stability tends to deteriorate, and if the number of moles of water is larger than the above range, curing and drying tend to be slow. Further, a production accelerator may be used to produce such a condensate of organosilane.

As such an accelerator, a compound represented by the general formula (V): M (OR) _x or a mineral acid can be used. In the general formula (V), M is Ti,
A metal such as Al, B, Zr, etc., wherein R has 2 to 5 carbon atoms
And x is an integer of 2 to 4.

Specific examples of the general formula (V) include tetra-i-propoxytitanium, tetra-n-butoxytitanium, tri-i-propoxyaluminum, and mono-sec.
-Butoxy-di-i-propoxyaluminum, diethoxyboron, di-n-propoxyboron, tetra-n-
Butoxyzirconium and the like, and mineral acids such as hydrochloric acid and sulfuric acid. The addition amount is preferably in the range of 0.05 to 2.0 parts by weight based on 100 parts by weight of the organosilane.

The solvent-soluble fluororesin used in the present invention is not particularly limited as long as it can be dissolved in an organic solvent usually used for paints, and conventionally known fluorocopolymers can be used. Can be used without any particular limitation, such as a lacquer type that cures without using a curing agent, a self-crosslinking type, a room temperature curing type that is used in combination with a curing agent, and a baking type.

Specifically, for example, Japanese Patent Application Laid-Open No. 57-3410
7, JP-A-57-78270, JP-A-59-102
No. 961, JP-A-59-120661, JP-A-59-12061
197471, JP-A-60-28458 and JP-A-6-28
1-112760, JP-A-61-43667, JP-A-61-57609, JP-A-61-111567, JP-A-61-210045, JP-A-61-247727
JP-A-61-258852, JP-A-62-841
No. 37, such as a fluorine-containing copolymer, modified copolymers and the like are exemplified as typical fluorine-containing copolymers,
It is not limited to these.

Specific examples of the copolymer include a fluoroolefin, a vinyl ether having a functional group, a vinyl ether having no functional group, and / or a copolymer containing vinyl ester carboxylate and other comonomer as essential components; Fluoroolefin, cycloalkyl vinyl ether, alkyl vinyl ether, copolymer containing hydroxyalkyl vinyl ether as an essential component; fluoroolefin,
A copolymer obtained by reacting a copolymer of an alkyl vinyl ether and a hydroxy vinyl ether with a dibasic acid anhydride and partially carboxylating the copolymer; at least one perhaloolefin selected from tetrafluoroethylene and chlorotrifluoroethylene; A hydroxyl group-containing copolymer obtained by hydrolyzing a copolymer of vinylidene fluoride, a vinyl ester and another monomer; at least one perhaloolefin selected from tetrafluoroethylene and chlorotrifluoroethylene, an α-olefin, A copolymer comprising hydroxyalkyl vinyl ether and another comonomer; a copolymer comprising one or more of chlorotrifluoroethylene, tetrafluoropropyl vinyl ether and a vinyl ether having a hydroxyl group, glycidyl group or amino group as a functional group Coalescence; Fluoroethylene and hydroxyl groups, a copolymer of a monomer and tetrafluoroethylene or chlorotrifluoroethylene having a functional group such as glycidyl group or carboxyl group and the like, Lumiflon LF100 as such commercially available products, Lumiflon LF200,
LUMIFLON LF210, LUMIFLON LF300, LUMIFLON LF400, LUMIFLON LF500, LUMIFLON L
F554, Lumiflon LF916 (trade names of Asahi Glass Co., Ltd.); Fluonate JZ-111-60, Fluonate HZ-1148-60, Fluonate K-700, Fluonate K-702, Fluonate K-703, Fluonate K-704 (Dainippon) Cefral coat manufactured by Central Glass Co., Ltd .; Dianal LR-2504, Dianar AR manufactured by Mitsubishi Rayon Co., Ltd.
-1262: Cotax FX-68, Cotax FX-96, Cotax FX-145, etc., manufactured by Toray Industries, Inc., are typical examples.

The solvent-soluble resin of the present invention comprises xylene,
Although it is soluble alone in toluene or the like and in a low-polarity organic solvent, it is also possible to mix and use another organic solvent if necessary. Other organic solvents include tetrahydrofuran, cyclic ethers such as dioxane, benzene,
Aromatic hydrocarbons such as toluene and xylene; ethyl acetate;
Esters such as butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; nitrogen-containing solvents such as dimethylformamide, dimethylacetamide, pyridine; halogen-containing solvents such as 1,1,1-trichloroethane and trichloroethylene. No.

The solvent-soluble fluororesin of the present invention can be produced by solution polymerization in the presence of a usual radical initiator.

The titanium oxide having photocatalytic activity used in the present invention means that a TiO ₂ sol is applied to a substrate material to form a thin film, and the thin film is dispersed in an aqueous solution of a metal salt having a catalytic function or a basic aqueous solution of a metal. Particle size 0.01-0.05 μm
About anatase-type TiO ₂ is in the sol state from several% to several tens%
It exists. Examples of the metal having a catalytic function include Cu, Ag, Fe, Pd, and Pt, and the salts may be nitrates, sulfates, acetates, and the like.

Further, it is possible to replace 10 to 50% by weight of the titanium oxide having photocatalytic activity of the present invention with at least one selected from the group consisting of activated carbon, silica gel, zeolite and calcium phosphate. Examples of the calcium phosphate include α-tricalcium phosphate, β-tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, and hydroxyapatite, with hydroxyapatite being particularly preferred.

If the replacement ratio is less than 10% by weight, no replacement effect is observed. Conversely, if it exceeds 50% by weight, the photocatalytic effect will be reduced, which is not preferable.

The intermediate coating composition of the present invention comprises at least one selected from the group consisting of a hydrolyzable silyl group-containing vinyl copolymer, a hydrolyzate of an organosilane and a partial condensate of a hydrolyzate of an organosilane. A hydrolyzable silicon compound is used as a binder.

The overcoat paint of the present invention is at least one selected from the group consisting of the hydrolyzable silyl group-containing vinyl copolymer, the hydrolyzate of organosilane and the partial condensate of the hydrolyzate of organosilane. A hydrolyzable silicon compound or a mixture of the solvent-soluble fluororesin and titanium oxide having photocatalytic activity;
Is 45 to 85, preferably 50 to 80.

Here, PWC stands for Pigment Wen.
It is light concentration (pigment weight concentration) and is calculated by the following formula.

[0066]

When the PWC is less than 45, the photocatalytic effect is not sufficiently exhibited. Conversely, if it exceeds 85, the film-forming properties decrease,
Undesirably, cracks and peeling occur.

The coating composition of the present invention can be used as a coating by mixing the above-described coating composition with various pigments, organic solvents or additives as required.

As the pigment, pigments that are usually used for paints can be used as they are. Specifically, titanium oxide, zinc oxide, iron oxide, colored inorganic pigments such as graphite, phthalocyanine blue, colored organic pigments such as benzidine yellow, quartz powder, alumina oxide, extender pigments such as precipitated barium sulfate, stainless powder, Representative examples include metal powders such as zinc powder, aluminum powder, bronze powder, and mica powder.

Examples of the organic solvent include hydrocarbon solvents such as toluene and xylene; ester solvents such as ethyl acetate and butyl acetate; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone; Representative examples include alcohol solvents such as butanol.

Examples of the additives include additives known as ordinary paint additives such as a surface conditioner, a dispersant, an ultraviolet absorber, a thickener, and a reaction control catalyst.

In the anticorrosion coating method of the present invention, first, the zinc rich paint is applied by spraying, brushing or the like on the steel surface which has been sufficiently rusted off by sand blasting or shot blasting.

In the present invention, the thickness of the dried coating film of the zinc rich paint is about 10 to 150 μm, preferably 15 to 75 μm.

If the film thickness is less than 10 μm, the desired anticorrosion property is hardly obtained, while if the film thickness exceeds 150 μm, cohesive failure is apt to occur in the dried coating layer of zinc-rich paint. There is a drawback that the coating layer is easily peeled off due to a strong impact, a mechanical stress, a thermal shock or the like.

The synthetic resin paint was applied on a zinc rich paint coating film obtained by drying the zinc rich paint at room temperature using a brush, a spray coater, a roller, or the like so as to have a dry film thickness of about 25 to 300 μm. Then, it is dried at room temperature. Usually, a synthetic resin coating film is formed in about 1 to 7 days.

Then, the intermediate coating is applied on the synthetic resin coating film by a brush, a spray coater, a roller or the like so that the dry film thickness becomes about 10 to 100 μm, and dried at normal temperature. Further, the top coat is dried on the intermediate coat by a brush, a spray coater, a roller or the like to have a dry film thickness of 10 to 100.
Apply to a thickness of about μm and dry at room temperature to finish. Thus, the coating film obtained by the method of the present invention has long-term NOx removal properties and antifouling properties, and has long-term weather resistance, long-term corrosion resistance, and excellent adhesion.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0078]

EXAMPLES In the examples, "part" or "%" indicates "part by weight" or "% by weight". First, prior to the examples, each paint was prepared according to the following composition.

Preparation of Zinc Rich Paint [Formulation 1] Potassium silicate aqueous solution (solid content 40%) 30 parts Zinc powder 70 parts

[Formulation 2] Ethyl silicate solution 25 parts Zinc powder 75 parts Ethyl silicate solution is trade name Colcoat 40 (manufactured by Nippon Colcoat Co., Ltd .; alcohol solution of 40% solid content; chain or branched having an average degree of condensation of about 4 to 5). Condensate mixture of tetraethyl orthosilicate].

[Formulation 3] (Main ingredient) Epoxy resin 6 parts Xylol 10 parts Methyl isobutyl ketone 9 parts Zinc dust 65 parts (Curing agent) Polyamide resin 4 parts Xylol 4 parts Isobutanol 2 parts The epoxy resin is a product manufactured by Shell Chemical Company. Name epicort #
1001 [epoxy equivalent of 450 to 520], and polyamide resin used was Tomide # 210 [trade name: 95 ± 5] manufactured by Fuji Kasei Co., Ltd.

The above Formulations 1 to 3 are zinc rich paint compositions, and zinc powder or a hardener is mixed with zinc powder at the time of use.

Preparation of Synthetic Resin Paint [Formulation 4] (Main agent) Bisphenol-type epoxy resin [trade name: Epicoat 828, manufactured by Shell Chemical Co., Ltd .: Epoxy equivalent: 184-194] 25 parts Titanium oxide pigment 20 parts Talc 15 parts Precipitable barium sulfate 15 parts Anti-settling agent (organic bentonite) 2 parts Methyl isobutyl ketone 13 parts Xylol 10 parts The composition was kneaded with a roller to obtain a main ingredient.

(Curing Agent) Polyamide resin [trade name: Tomide # 245, manufactured by Fuji Kasei Kogyo Co., Ltd .; active hydrogen equivalent: 90] 60 parts Isobutanol 40 parts The mixture was stirred with a disper to prepare a curing agent.

Immediately before use, the curing agent 20 was added to 80 parts of the main agent.
Were mixed to obtain a coating composition of Formulation 4.

[Formulation 5] Soybean oil-modified medium oil type alkyd resin (oil length 50%, acid value 5) 15 parts Chloride rubber 15 parts Chlorinated paraffin 40% 7 parts Titanium oxide 15 parts Metal dryer 2 parts Anti-skinning agent 0 .5 parts Anti-settling agent 1 part Xylol 44.5 parts

[Formulation 6] Acrylic resin [manufactured by Dainippon Ink and Chemicals, Inc., trade name Acridic A-169, nonvolatile content 50%] 40 parts Titanium oxide 20 parts Anti-settling agent 1 part Xylol 39 parts

[Formulation 7] Vinyl chloride resin (trade name: VYHH, manufactured by Union Carbide) 20 parts Dibutyl phthalate (DBP) 9 parts Titanium oxide 10 parts Anti-settling agent 1 part Methyl isobutyl ketone 30 parts Xylol 20 parts butyl acetate 10 parts

[Formulation 8] Phenol resin [Hitanol 1131 manufactured by Hitachi Chemical Co., Ltd.] 20 parts Soybean oil-modified medium oil type alkyd resin (identical to Formulation 5) 15 parts Toluol 20 parts Ethyl acetate 15 parts Titanium oxide 30 parts

[Formulation 9] (Main ingredient) Polyester resin (trade name: Desmophen 1100, manufactured by Bayer) 14.1 parts Polyester resin (trade name: Desmophen 800, manufactured by Bayer) 14.1 parts Titanium oxide 10 parts Xylol 6 parts Acetic acid Ethyl 6 parts Butyl acetate 6 parts Cellosolve acetate 4.8 parts A polyvalent isocyanate as a curing agent [trade name: Mitec GP101A manufactured by Mitsubishi Kasei Kogyo Co., Ltd .: nonvolatile content 7]
5%] at the time of coating 39 parts.

Preparation of Intermediate Coating [Formulation 10] 45 parts of xylene and 40 parts of isobutanol were added and mixed, and then heated to 85 ° C. with stirring. Next, a mixed solution of 50 parts of isobutyl methacrylate, 35 parts of 2-ethylhexyl methacrylate, 15 parts of γ-methacryloxypropylmethoxysilane, and 1.5 parts of azobisisovaleronitrile was added dropwise at 85 ° C. over 3 hours. The temperature was raised to 0 ° C. and maintained for 2 hours to terminate the reaction to obtain a silyl group-containing vinyl resin solution having a nonvolatile content of 55%. The vinyl resin has a weight average molecular weight of 14,000 and has an average of about 7 silyl groups per polymer molecule. 25 parts of titanium oxide, 15 parts of calcium carbonate, and precipitated barium sulfate 1 were added to 100 parts of the silyl group-containing vinyl resin solution.
0 parts were added and the mixture was kneaded with a pot mill for 24 hours to obtain a base material for an intermediate coating material. Immediately before use, a hardening accelerator (dibutyltin laurate) is used as the main agent: a hardening accelerator in a ratio of 100: 0.
It is added at a ratio of 1 to give an intermediate coating.

Preparation of Top Coating [Formulation 11] 40 parts of methyltriethoxysilicate and isopropyl
54 parts of alcohol are stirred at 40 ° C. and then
A mixture consisting of 0.3 parts of N-hydrochloric acid and 5.7 parts of water is mixed for 90 minutes
Dropped over time. Stir at 40 ° C for 4 hours after dropping
And a non-volatile content of methyltriethoxysilicate of 40%.
Hydrolysis condensate solution “hereinafter referred to as hydrolysis condensate A-1
U ". The polystyrene equivalent weight of the condensate is
The average molecular weight was 10,000. This hydrolysis condensation
Material A-1 100 parts of photocatalytic titanium oxide SSP-25
(Sakai Chemical Industry Co., Ltd., average particle size 9nm, specific surface area
270m ^Two / G) 160 parts, xylol 10 parts, isop
10 parts of propyl alcohol was added to make a paint. Cured to this
Add 0.1 part of accelerator (dibutyltin laurate) and add
Use paint. The PWC was 80.

[Formulation 12] 35 parts of tetraethoxysilicate [“ethyl silicate 40” (trade name, manufactured by Nippon Colcoat)] and 61 parts of isopropyl alcohol at 40 ° C.
Then, a mixture consisting of 1 part of 1-N-hydrochloric acid and 3 parts of water was added dropwise thereto over 90 minutes. 40 after dripping
The mixture was further stirred at 4 ° C. for 4 hours to obtain a hydrolytic condensate solution of tetraethoxysilicate having a nonvolatile content of 35% [hereinafter referred to as hydrolytic condensate A-2]. The polystyrene equivalent weight average molecular weight of the condensate was 13,000. To 100 parts of this hydrolysis condensate A-2, 120 parts of photocatalytic titanium oxide SSP-25, 40 parts of molecular sieve 4A (trade name, manufactured by Union Showa Co., Ltd., zeolite), 10 parts of xylol, and 10 parts of isopropyl alcohol were added to form a paint. . In addition, a curing accelerator (dibutyltin laurate)
Add 0.1 part to make a top coat. The PWC was 80.

[Formulation 13] Solvent-soluble fluororesin [“Lumiflon LF200” (trade name, manufactured by Asahi Glass Co., Ltd .; nonvolatile content 6)
0 ± 1%)] 50 parts, photocatalytic titanium oxide SSP-25
62 parts, 20 parts of molecular sieve 4A and 20 parts of xylol were added to form a coating. To this was added 5.4 parts of a curing agent [“Coronate HX” (trade name, manufactured by Nippon Polyurethane Industry Co., Ltd .; non-yellowing type isocyanate, nonvolatile content: 100%) to give a top coat.

[Formulation 14] In the above [Formulation 11],
160 parts of titanium oxide photocatalyst SSP-25 is changed to 26.7 parts of rutile type titanium oxide [“Taipaek CR-95” (trade name, manufactured by Ishihara Sangyo Co., Ltd.)] to give a top coat. PWC
Was 40.

[Formulation 15] In the above [Formulation 11],
160 parts of photocatalytic titanium oxide SSP-25 was changed to 26.7 parts to obtain a top coat. The PWC was 15.

[Formulation 16] In [Formulation 9], titanium oxide is changed to titanium oxide photocatalyst SSP-25.

[Formulation 17] Lumiflon LF-2005
0 parts, Taipaque CR95 23.6 parts, Xylol 1
Add 0 parts to make a top coat.

Examples 1 to 7 A steel plate of 150 × 70 × 3.2 mm (JIS G310
1, SS-400) by shot blasting,
After the rust and oil were completely removed, zinc rich paint was first applied by air spray to a dry film thickness of 35 ± 5 μm in accordance with the coating system shown in Table 1.
After drying at 5% RH for 3 days, a zinc rich paint coating was obtained.

Next, a synthetic resin paint was applied thereon by air spraying to a dry film thickness of 100 ± 10 μm, and dried at 20 ° C. and 65% RH for 1 day to obtain a synthetic resin coating film.

On top of this, an intermediate coating was applied by air spraying to a dry film thickness of 30 ± 5 μm.
% RH for 1 day to obtain an intermediate coating film. Further, a top coat was applied by air spray to a dry film thickness of 50 ± 10 μm, and dried at 20 ° C. and 65% RH for 7 days.

Each of the obtained test pieces was subjected to a comparative test described later.

Comparative Examples 1 to 6 Test pieces were obtained in the same manner as in the above examples based on the coating systems shown in Table 2, and then subjected to comparative tests.

[0104]

Table 2

The test pieces obtained in Examples 1 to 7 and Comparative Examples 1 to 6 were subjected to a 1000-hour salt water spray test, a 1000-hour salt water immersion test, a 1000-hour sunshine weatherro test, and a measurement of NOx removal. Provided. Table 3 shows the results.

<NOx removal rate> The test method and conditions are shown below and in FIG.

[Test Method] Exposure container 12 × 24 cm Exposure window Pyrex glass panel 10 × 10 cm ² Panel-exposure window interval 0.5 cm Light source Toshiba black light (15 W; 20 cmL; 2 wires) Irradiation distance 20 cm Principal wavelength 354 nm UV-A The amount 0.4 mW / cm ² inlet gas composition NOx 6 ppm + air gas velocity flow rate 3 l / min line speed 8.3 cm / sec NOx meter Shimadzu CLM-500 chemiluminescence sensitivity full-scale 10 ppm ± 0.2 ppm conditioned dark atmosphere Gas for 2 hours

Table 3

Note 1) Spraying for 1000 hours according to the method of JIS K 5400 Note 2) Immersion in 3% by weight aqueous sodium chloride solution at 20 ° C for 1000 hours Note 3) 1000 hours Note 4) 60 ° -60 ° mirror surface Gloss retention rate * 5) NOx removal rate (%) = (1-NOx concentration at exit / NOx concentration at entrance) x 100 Measured value 1 hour after UV irradiation

[0111]

The anti-corrosion coating method of the present invention is excellent in weather resistance, anti-corrosion, and adhesion, and is also excellent in NOx removal and anti-fouling properties.

[Brief description of the drawings]

FIG. 1 is a diagram showing a method for measuring a NOx removal rate.

Claims (2)

[Claims] 1. A coating material layer comprising a zinc-rich paint is provided on a coating, and an undercoat layer comprising a synthetic resin is provided on the zinc-rich paint coating layer. Curing at least one hydrolyzable silicon compound and a pigment selected from a silyl group-containing vinyl copolymer having decomposability, a hydrolyzate of an organosilane and a partial condensate of a hydrolyzate of an organosilane. Selected from a hydrolyzable silyl group-containing vinyl copolymer, an organosilane hydrolyzate and a partial condensate of an organosilane hydrolyzate. It has an overcoat layer obtained by curing at least one hydrolyzable silicon compound or a solvent-soluble fluororesin, and a titanium oxide having photocatalytic activity so as to have a PWC of 45 to 85. Corrosion protective coating according to claim. 2. (A) a step of applying a zinc-rich paint on an object to be coated and drying at room temperature to form a zinc-rich paint coating; (B) a step of applying a synthetic resin coating on the zinc-rich paint coating A step of applying as an undercoat paint and drying at room temperature to form an undercoat film; (C) a hydrolyzable silyl group-containing vinyl copolymer, a hydrolyzate of organosilane and an organosilane on the undercoat film (C) a step of applying a paint containing at least one hydrolyzable silicon compound selected from partial condensates of the hydrolyzate as a binder as an intermediate coating and drying it at room temperature to form an intermediate coating film; On the intermediate coating film, a hydrolyzable silyl group-containing vinyl copolymer, at least one hydrolyzate selected from hydrolysates of organosilanes and partial condensates of hydrolysates of organosilanes A paint containing a dissolvable silicon compound or a solvent-soluble fluororesin, and a titanium oxide having photocatalytic activity, wherein the titanium oxide has a PWC of 45 to 85 as a top coat, and is dried at room temperature to obtain a top coat. And a process for forming an anticorrosive coating.