JP2003268295A - Method for preventing corrosion of weather-resistant steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing corrosion of a weather-resistant steel. <P>SOLUTION: A colored coating film having a dry film thickness of 50-90 μm which comprises (1) an inorganic resin or an organic/inorganic composite resin, (2) 0.5-30 pts.mass, based on the solids of the inorganic resin or the organic/inorganic composite resin, of a first compound selected from the group consisting of NiSO<SB>4</SB>, NiCO<SB>3</SB>, Ni<SB>3</SB>(PO<SB>4</SB>)<SB>2</SB>, Ni(NO<SB>3</SB>)<SB>2</SB>, CuO, Cu<SB>3</SB>(PO<SB>4</SB>)<SB>2</SB>, AlPO<SB>4</SB>, Al<SB>2</SB>(MoO<SB>4</SB>)<SB>3</SB>and CuCO<SB>3</SB>Cu(OH)<SB>2</SB>, (3) 0.5-25 pts.mass, based on the solids of the inorganic resin or the organic/inorganic composite resin, of a second compound selected from the group consisting of H<SB>3</SB>[PW<SB>12</SB>O<SB>40</SB>]nH<SB>2</SB>O, H<SB>4</SB>[SiW<SB>12</SB>O<SB>40</SB>]nH<SB>2</SB>O, H<SB>3</SB>[PMo<SB>12</SB>O<SB>40</SB>]nH<SB>2</SB>O, Na<SB>3</SB>[PMo<SB>12</SB>O<SB>40</SB>]nH<SB>2</SB>O, H<SB>3</SB>[PW<SB>12-x</SB>Mo<SB>x</SB>O<SB>40</SB>]nH<SB>2</SB>O (0<x<12), H<SB>4</SB>[SiMo<SB>12</SB>O<SB>40</SB>]nH<SB>2</SB>O, phosphoric acid, nitric acid, molybdic acid, tungstic acid and boric acid and (4) a coloring agent is formed on the surface of a weather- resistant steel. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel coating method for weather resistant steel, and more specifically, it prevents flow rust (red rust) of weather resistant steel and forms protective rust stable against corrosion. The present invention relates to an anticorrosion method for weather-resistant steel, which can impart various colors in harmony with the environment and can also provide long-term weather resistance and rust resistance in a process-saving manner.

[0002]

2. Description of the Related Art Generally, carbon steel is often used for steel structures because of its low cost. However, in carbon steel, moisture in the air (rainfall, humidity, etc.) and oxygen come into contact with the surface of the steel material, and red rust occurs in a short period of time. As a method for preventing the generation of red rust, a method of applying a paint is generally used. In this method, it is common to apply a coating having good durability in order to reduce repainting as much as possible. For example, inorganic zinc rich paint coating → epoxy resin paint mist coat → epoxy resin paint base coat (2
→ Epoxy resin paint intermediate coating → Polyurethane resin paint Top coating is a typical steel coating system that has a durability of 15 years or more. This coating system has the advantage that it can maintain the aesthetic appearance with a color that is in harmony with the environment and maintain long-term rust prevention, but on the other hand, this coating system has a large film thickness and requires 6 additional coatings, so it is completed. It takes time and cost. Therefore, in recent years, cases of using weather resistant steel having good corrosion resistance for steel structures have been increasing.

Weather-resistant steels are generally P, Cu, Cr, N.
It is a low alloy steel to which elements such as i have been added. This steel material has the property of forming rust that has a protective effect against corrosion in the outdoors for more than a dozen years (hereinafter referred to as "protection rust"), and eliminating the need for rust-proofing work thereafter, so-called maintenance-free. is doing. The protective action against this corrosion is to control rust with so-called rust, and this protective rust is
Amorphous iron oxyhydroxide containing a large amount of water of crystallization is the main component, and it is believed that this contributes to the formation of protective rust that is dense and has good adhesion. At the time of repainting existing steel structures, a lot of red rust is usually generated on the surface of steel, and even if paint is repainted on such a surface, swelling or peeling will occur in the coating film and Cannot protect from rust for a period of time.

[0004]

However, if the weather-resistant steel material is used without any treatment, floating rust such as red rust or yellow rust or flow rust occurs during the period until protective rust is formed. Not only is it unfavorable in appearance, but it is also a cause of pollution of the surrounding environment. Further, in the conventional example, there is a surface treatment method by painting to obtain protective rust on the surface of weather resistant steel, but it still takes a long period of several years until protective rust is formed, during which the coating film itself It causes problems such as whitening, blistering, and peeling. Further, in order to make the generated rust inconspicuous, the color tone is unified to the rust color, and no consideration has been given to impart various colors in harmony with the environment like painting on carbon steel. Existing weather-resistant steel in which the occurrence of red rust or yellow rust has become noticeable is left as it is, or if it is left to stand until protective rust is formed, or when repairing it, usually after removing rust completely, organic zinc rich It was general to apply the paint → epoxy resin paint undercoating → epoxy resin paint intermediate coating → topcoating 4 to 5 times, but there was a problem that the coating process was many and took time and cost.

[0005]

Means for Solving the Problems
As a result of diligent study to solve the problem, protection on the weather resistant steel surface
Form rust to maintain rust resistance for a long time, and also have good weather resistance
By applying a colored paint containing a different resin and colorant,
Maintains weather resistance for a long time and enables arbitrary coloring,
The corrosion-resistant method for weatherproof steel, which is a process-saving process, has been completed. Immediately
The present invention has the following components (1)
Machine resin or organic-inorganic composite resin, (2) the inorganic resin or
0.5 to 30 parts by mass based on the solid content of the organic-inorganic composite resin
Of NiSO_Four, NiCO₃, Ni₃(PO_Four)₂, Ni (N
O₃)₂, CuO, Cu₃(PO_Four)₂, AlPO_Four, Al₂
(M_oO_Four)₃And CuCO₃Cu (OH)₂A group of
A first compound selected from (3) the inorganic resin or
0.5 to 25 parts by weight based on the solid content of the inorganic composite resin
Of H₃[PW₁₂O₄₀] ・ NH₂O, H_Four[SiW₁₂O₄₀]
・ NH₂O, H₃[PMo ₁₂O₄₀] ・ NH₂O, Na₃[P
Mo₁₂O₄₀] ・ NH₂O, H₃[PW_12-xMo_xO_{Four 0}] ・
nH₂O (0 <x <12), H_Four[SiMo₁₂O₄₀] ・ N
H₂O, phosphoric acid, nitric acid, molybdic acid, tungstic acid
And a second compound selected from the group consisting of boric acid, and
(4) For the solid content of the inorganic resin or organic-inorganic composite resin
And contains 2 to 40 parts by weight of a coloring agent, and has accelerated weather resistance.
Test sunshine weather meter 300 hours after irradiation
Water vapor transmission at 25 ° C with gloss retention of 80% or more
Degree 3 to 100g / m²/ Day / 50 μm
Mostly, a colored coating film having a dry film thickness of 50 to 90 μm is formed.
It relates to the anticorrosion method for weather-resistant steel characterized by
is there.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The weather resistant steel used in the present invention is called SPA material or SMA material, and is specified in JIS G3141, and if rust or the like adheres, it is blasted or pickled as pretreatment. However, it is also preferable to remove only floating rust.

Next, the paint used in the present invention will be described. The colored coating used to form the colored coating film of the present invention is preferably a one-coat finish type because it is a process-saving process, and it forms a protective rust stable against corrosion at an early stage, and has a long-term rust prevention property. And that it has weather resistance, and can be arbitrarily colored in accordance with the desire. Therefore, the colored coating material used in the present invention is an inorganic resin or an organic-inorganic composite resin, a second compound of a specific first compound, a colorant, and a curing agent for the inorganic resin and the organic-inorganic composite resin that are optionally blended. Agent, a curing accelerator, a silane coupling agent, a pollution-free rust preventive pigment, a solvent, a neutralizing agent, and further various additives such as a dispersant, an ultraviolet absorber and an antibacterial agent. The form of the colored paint used may be solvent-based, water-based, or solvent-free.

The inorganic resin or organic-inorganic composite resin used as a binder in the colored coating material has a water vapor permeability of 3 to 100 in the formed colored coating film in order to form early protective rust.
It is necessary to fall within the range of g / m ² / day / 50 μm. When the water vapor permeability is less than 3 g / m ² / day / 50 μm, the amount of water that penetrates under the colored coating film is extremely small and does not contribute to the formation of protective rust. On the other hand, when the water vapor permeability exceeds 100 g / m ² / day / 50 μm, on the contrary, excessive water permeates under the coating film and protective rust is not formed, which may cause swelling of the coating film or generation of rust. The water vapor transmission rate referred to in the present specification is the water vapor transmission rate measured by the method defined in JIS K7129. That is, the water vapor permeability is calculated by sensing the amount of water vapor permeating from the front surface to the back surface of the isolated coating film per unit area, unit time, and film thickness by a humidity sensor.

Generally, there is a correlation between the water vapor permeability and the anticorrosion property, and a large value of the water vapor permeability means that the barrier property by the coating film is poor (the anticorrosion property is poor). In order to form protective rust early like the invention,
It is necessary to allow water vapor to permeate within a certain range.
As the inorganic resin or organic-inorganic composite resin used in the colored paint, it is necessary to use a resin having good weather resistance.
That is, the accelerated weathering test of the obtained colored coating film has a gloss retention of 80 after 300 hours of sunshine weather meter irradiation.
% Or more, preferably 90% or more (eg, maximum, 95
% Is appropriate) resin to maintain. Gloss retention rate is 8
If it is less than 0%, whitening, blistering, peeling and the like are likely to occur in the coating film, which is not preferable. The accelerated weather resistance test sunshine weather meter referred to herein is JI
It is an accelerated weather resistance tester that correlates with the actual outdoor exposure of the sunshine carbon arc lamp type specified by S K5400, and the gloss retention rate is calculated from the 60 degree specular gloss specified by JIS K5400 by the following formula. It refers to the degree of residual gloss calculated.

Gloss retention rate = (Gloss after 300 hours of sunshine weather meter irradiation) × 100 / Initial gloss (%) Specific examples of such an inorganic resin having good weather resistance include:
For example, the general formula R ¹ _n Si (OR ² ) _4-n [wherein, R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is
It is an alkyl group having 1 to 5 carbon atoms, and n is 0 or 1. ] The hydrolysis-condensation product of the alkyl silicate shown by these is mentioned suitably. In the above formula, examples of the organic group as R ¹ include an alkyl group, a cycloalkyl group, an aryl group, a vinyl group and the like. Here, the alkyl group may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, and n.
Examples thereof include alkyl groups such as -propyl group, i-propyl group, n-butyl group, i-butyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, heptyl group, and octyl group. Preferred alkyl groups have 1 to 4 carbon atoms.

Preferable examples of the cycloalkyl group include a cyclohexyl group, a cycloheptyl group, a cyclooctyl group and the like. As the aryl group, for example,
Examples thereof include a phenyl group and a naphthyl group. Each of the above functional groups may optionally have a substituent. Examples of such a substituent include a halogen atom (eg, chlorine atom, bromine atom, fluorine atom, etc.), (meth) acryloyl group, amino group, mercapto group, glycidoxy group, epoxy group, alicyclic group, etc. Is mentioned. The alkyl group as R ² may be linear or branched. Examples of such an alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i
-Butyl group, s-butyl group, t-butyl group, pentyl group and the like can be mentioned, and preferable alkyl group has 1 to 2 carbon atoms.
It belongs to an individual.

Specific examples of such alkyl silicates include tetramethyl silicate, tetraethyl silicate, tetra-n-propyl silicate, tetra-i-
Alkyl silicates such as propyl silicate and tetra-n-butyl silicate when n is 0; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyl Triethoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryl Oxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-
N such as mercaptopropyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, γ-aminopropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane, and 3,4-epoxycyclohexylethyltriethoxysilane.
Examples thereof include alkyl silicates in which 1 is 1. From the viewpoint of coating workability, the degree of condensation of these partially hydrolyzed condensates of alkyl silicates is preferably 30 or less, more preferably 10 or less.

The catalyst used in the partial hydrolysis and condensation reaction of the above alkyl silicate is, for example, dibutyltin dilaurate, dibutyltin dimaleate,
Organotin compounds such as dioctyl tin dilaurate, dioctyl tin dimaleate, dioctyl tin maleate, tin octylate; phosphoric acid, monomethyl phosphate,
Phosphoric acid or phosphoric acid ester such as monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; diisopropoxybis (acetylacetate) titanium, Organic titanate compounds such as diisopropoxybis (ethylacetoacetate) titanium; organic aluminum compounds such as tris (ethylacetoacetate) aluminum, tris (acetylacetonato) aluminum; tetrabutylzirconate, tetrakis (acetylacetonato) zirconium, Tetraisobutyl zirconate,
Representative examples include organic zirconium compounds such as butoxytris (acetylacetonato) zirconium.

On the other hand, examples of the organic-inorganic composite resin having good weather resistance include, for example, fluororesin which is generally used as a coating material for top coating, epoxy resin, acrylic resin and the like, in which a hydrolyzable silyl group is introduced. Furthermore, the general formula R ¹ _n Si (OR ² ) _4-n [in the formula, the definitions of R ¹ , R ² and n are as described above. ] It can be easily prepared by subjecting the organosilane or the partial hydrolysis condensate thereof represented by Examples of the fluororesin include, for example, vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, bromotrifluoroethylene,
Typical examples include chlorotrifluoroethylene, pentafluoropropylene, hexafluoropropylene, and (per) fluoroalkyl trifluorovinyl ether [where the (per) fluoroalkyl group has 1 to 18 carbon atoms]. .

Of these, vinyl fluoride, a group consisting of vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene and (per) fluoro (C ₃ -C ₄ ) alkyltrifluorovinyl ether. It is preferable to use at least one selected from Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, alkyl ether type epoxy resin, and hydrogenated bisphenol A type epoxy resin.
As the epoxy resin, one kind of the above epoxy resins may be used alone, or two or more kinds of epoxy resins may be used.

Examples of the acrylic resin include (meth)
(Meth) acrylic acid ester such as methyl acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate; (meth) acrylic acid, itacone Acids, carboxylic acids such as fumaric acid, and acid anhydrides such as maleic anhydride; epoxy compounds such as glycidyl (meth) acrylate; acrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, etc. Although it is a copolymer of vinyl monomers,
By radically copolymerizing allyl (meth) acrylate, diallyl phthalate or the like during the production of the copolymer,
It is possible to introduce a carbon-carbon double bond into the vinyl resin for the hydrosilylation reaction.

As other production methods, the above-mentioned vinyl-based monomers, hydroxyl group-containing monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 2-hydroxyvinyl ether, and γ- ( (Meth) acryloxypropyltrimethoxysilane, γ- (meth) acryloxypropyltriethoxysilane, β- (meth) acryloxyethyltrimethoxysilane, β- (meth) acryloxyethyltriethoxysilane, γ- (meth ) Acryloxypropylmethyldimethoxysilane, γ- (meth) acryloxypropylmethyldiethoxysilane, γ- (meth) acryloxypropylmethyldipropoxysilane, γ- (meth) acryloxybutylphenyldimethoxysilane, γ- (meth ) Acryloxypropyl Method of the silyl group-containing vinyl compounds such as ethyl silane radical polymerization are preferably exemplified.

Specific examples of these silyl group-containing vinyl resins include Kaneka Zemulac manufactured by Kanegafuchi Chemical Industry as a commercial product. Examples of the organosiloxane used for introducing a hydrolyzable silyl group into a fluororesin, an epoxy resin, or an acrylic resin include general formulas R ¹ _n Si (OR ² ) _4-n [wherein R ¹ , R ² and n are as defined above. ]
The organosilane represented by or a partially hydrolyzed condensate of the organosilane is preferably used.

Next, a fluororesin, an epoxy resin or an acrylic resin having a hydrolyzable silyl group is added to a compound represented by the general formula R ¹ _n Si (OR ² ) _4-n [wherein R ¹ , R ² and n are as described above]. As defined. ]
Is hydrolyzed and condensed with the organosilane or a partial hydrolyzed condensate thereof. The organosilanes may be used alone or in a mixture. The hydrolysis-condensation product of organosilane has a polystyrene-reduced weight average molecular weight of, for example, 300 to 5,000, preferably 500 to
4200 is suitable. By using such a condensate, a coating film having good storage stability and good adhesion can be obtained. Specific examples of such condensates include SR2402 manufactured by Toray Dow Corning Co., Ltd. as a commercial product,
DC3037, DC3074; KR manufactured by Shin-Etsu Chemical Co., Ltd.
-211, KR-212, KR-213, KR-21
4, KR-216, KR-218; TSR-145, TSR-160, TSR-16 manufactured by Toshiba Silicone Co., Ltd.
5, YR-3187 and the like are preferable.

The hydrolytic condensation reaction with the organosilane or its hydrolytic condensate is carried out by treating the mixture of the above components in the presence of water, optionally a catalyst, for example at 40-80 ° C., preferably 45-65 ° C. A method of reacting while stirring for 2 to 10 hours is suitable, but not limited to this method. Examples of the hydrolysis-condensation reaction catalyst include trimethoxyborane, trialkoxyborane such as triethoxyborane, tri-n-butoxyethylacetoacetate zirconium, di-n-butoxydi (ethylacetoacetate) zirconium, and tetrakis (ethylacetoacetate). Acetate) zirconium chelate compounds such as zirconium, diisopropoxybis (acetylacetate) titanium, diisopropoxybis (ethylacetoacetate) titanium chelate compounds, monoacetylacetatebis (ethylacetoacetate) aluminum, diisopropoxyethyl Examples thereof include organometallic compounds such as aluminum chelate compounds such as acetoacetate aluminum. The hydrolysis-condensation reaction product is a polyorganosiloxane resin solution having a mercapto group in a solution state due to an alcohol content produced in the reaction, or the alcohol content and an organic solvent described later, which is added as necessary. Can be synthesized.

NiSO used in the present invention for coloring paints_Four, N
iCO₃, Ni₃(PO_Four)₂, Ni (NO₃)₂, CuO, C
u₃(PO_Four)₂, AlPO_Four, Al₂(M_oO_Four)₃And Cu
CO ₃Cu (OH)₂A first choice selected from the group consisting of
The compound densifies the generated rust and improves the barrier property of the rust layer.
The effect of increasing the weather resistance and corrosion resistance of steel through
Have fruit. Especially NiSO_Four, NiCO₃, Ni₃(P
O_Four)₂, Ni (NO₃)₂Is a coast with a large amount of incoming salt particles
It is effective in forming fine rust in the zone. First combination
The product is based on the solid content of the inorganic resin or the organic-inorganic composite resin.
0.5 to 30 parts by mass, preferably 8 to 25
Can be used in. If the amount is less than 0.5 part by mass, the above effect
If there is no fruit, while it exceeds 30% by mass, the stability of the paint
Causes a problem.

H ₃ [P
W ₁₂ O ₄₀ ] · nH ₂ O, H ₄ [SiW ₁₂ O ₄₀ ] · nH ₂ O,
H ₃ [PMo ₁₂ O ₄₀ ] ・ nH ₂ O, Na ₃ [PMo
₁₂ O ₄₀ ] ・ nH ₂ O, H ₃ [PW _12-x Mo _x O ₄₀ ] ・ nH ₂
O (0 <x <12), H ₄ [SiMo ₁₂ O ₄₀ ] ・ nH
The second compound selected from the group consisting of ₂ O, phosphoric acid, nitric acid, molybdic acid, tungstic acid, and boric acid reaches the steel material interface and ^converts Fe ²⁺ generated by the corrosion reaction there into Fe ³⁺ . Oxidize. Fe ²⁺ is involved in the formation of Fe ₃ O ₄ , which becomes harmful rust that deteriorates the weather resistance and corrosion resistance of steel materials,
On the other hand, Fe ³⁺ is involved in the formation of α-FeOOH which becomes stable rust which improves the weather resistance and corrosion resistance of the steel material. Therefore, in order to form stable rust at an early stage, it is important to oxidize Fe ²⁺ generated by the corrosion reaction to Fe ³⁺ as ^quickly as possible, and the second compound promotes this oxidation.
Further, the second compound imparts cation selectivity to the formed rust layer, and is therefore effective in preventing chlorine ions, which are harmful to rust stabilization, from permeating the steel material interface. Such action and effect are appropriately added in an amount of 0.5 to 25 parts by mass, preferably 3 to 21 parts by mass, based on the solid content of the inorganic resin or the organic-inorganic composite resin. If the compounding amount is less than 0.5 part by mass, the above-mentioned effect is not obtained, while 25
If it exceeds the amount by mass, there is a problem in the stability of the paint.

Specific examples of the color pigments used in the color coating composition of the present invention for coloring in accordance with the demand include white pigments such as titanium dioxide and zinc oxide, carbon black and graphite. Used for normal paints such as black pigments, molybdate orange, red pigments such as permanent carmine and quinacridone red, quinophthalene yellow, yellow pigments such as permanent yellow, phthalocyanine green, green such as phthalocyanine blue, and blue pigments. Representative pigments of each color are listed. Furthermore, an extender pigment may be used in combination with the coloring pigment in the colored coating material of the present invention. The color pigment varies depending on its type, but it is suitable to use in an amount of 2 to 40 parts by mass, preferably 10 to 30 parts by mass, based on the solid content of the inorganic resin or the organic-inorganic composite resin.

The colored coating material used in the present invention preferably further contains a silane coupling agent in order to improve the adhesion to the weather resistant steel material. Examples of the silane coupling agent include γ-chloropropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-methacryloxypropyltrimethoxysilane, and the like. β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β- (aminoethyl) amino Propyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethylmethoxysilane, γ-glycidoxypropyldimethylethoxysilane, etc. It is cited as typical. The silane coupling agent is an inorganic resin or organic-inorganic composite resin solid content 1
It is suitable to use it in an amount of, for example, 0.1 to 8 parts by mass, preferably 1 to 5 parts by mass with respect to 00 parts by mass. If the amount is less than 0.1 part by mass, the adhesion to the weather resistant steel tends to deteriorate, while if it exceeds 8 parts by mass, the stability of the coating tends to decrease.

The coloring paint used in the present invention may contain a pollution-free rust preventive pigment. As such a pollution-free rust-preventive pigment, for example, a chrome-free or lead-free rust-preventive pigment can be used. Specific examples of such rust-preventive pigment include aluminum powder, zinc powder, and phosphorus. Aluminum phosphate, zinc phosphate, zinc phosphite, potassium phosphite, calcium phosphite, aluminum phosphite, zinc calcium phosphate, zinc aluminum phosphate, aluminum tripolyphosphate, cyanamide zinc, zinc molybdate, phosphomolybdic acid Typical examples are rust preventive pigments such as zinc, aluminum phosphomolybdate, calcium molybdate, and hydrocalumite, and these are used as one kind or as a mixture of two or more kinds. The rust preventive pigment is, for example, 1 to 80 parts by mass, preferably 5 parts by mass with respect to 100 parts by mass of the solid content of the inorganic resin and the organic-inorganic composite resin.
It is suitable to use in an amount of -60 parts by weight. If the amount of the rust preventive pigment is less than 1 part by mass, the rust preventive property tends to be insufficient, while if it exceeds 80 parts by mass, the stability of the coating tends to deteriorate. In the colored paint used in the present invention, it is possible to use an organic rust preventive together with the rust preventive pigment.

Specific examples of the organic rust preventive agent include conductive polyaniline which has a function to passivate the surface of the steel material and make the potential uniform, and strengthens the adhesion between the colored coating film and the weather resistant steel.
Typical examples include benzothiazothiosuccinic acid, diphenylthiocarbazone, N, N-diphenylethylenediamine, S-diphenylcarbazide, and phenociazoline. The organic rust preventive is, for example, 0% with respect to 100 parts by mass of the inorganic resin and the organic-inorganic composite resin solid content.
It is suitable to use in an amount of ˜40 parts by mass, preferably 2 to 30 parts by mass.

Next, a method for coating weather resistant steel will be described.
The weather-resistant steel that has been blasted or not treated at all is coated with the above coating material by means of brushing, spraying, rollers or the like to give a dry film thickness of 50 to 90 μm, preferably 60 to 90 μm.
The colored coating film of the present invention can be formed by coating so as to have a thickness of 80 μm and naturally drying or forcibly drying at a temperature of, for example, 100 ° C. or less.

If floating rust is generated on the surface of the weather resistant steel, remove only the floating rust with a wire brush or the like,
Similarly, coating and drying can be performed to form the colored coating film of the present invention. In addition, in order to further improve durability after applying the above-mentioned colored paint, a pigmented top-coating paint that is usually used and has a gloss retention of 80% or more after 300 hours of accelerated weather resistance test sunshine weather meter irradiation, preferably Can be coated with a colored top coat which forms a colored top coat having 90% or more (maximum will be around 95%). As the resin used in the colored top coating, specifically, the inorganic resin or organic-inorganic composite resin used in the colored coating can be used as it is. The colored top coating film can be applied to a thickness of 10 to 60 μm, preferably 15 to 30 μm.

[0029]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, "part" and "%"
Is based on mass.

Synthesis Example 1 The following silicone intermediate was charged into a reactor equipped with a reflux condenser and a stirrer and stirred at 60 ° C. for 3 hours to obtain an alkoxysilicate hydrolyzate resin (resin 1). Shin-Etsu Silicon Co., Ltd. KBM13 45.0 parts Shin-Etsu Silicon Co., Ltd. KBM103 25.0 parts Toshiba Dow Corning Co., Ltd. SH6018 25.0 parts

Synthesis Example 2 A reactor equipped with a reflux condenser and a stirrer was charged with the following silicone intermediate and stirred at 60 ° C. for 3 hours to obtain an alkoxysilicate hydrolyzate resin (resin 2). Shin-Etsu Silicone KBE014 13.5 parts Shin-Etsu Silicone KBM103 11.5 parts Toshiba Dow Corning SR2402 75.0 parts

Synthesis Example 3 A reactor equipped with a reflux condenser and a stirrer was charged with the following silicone intermediate and stirred at 60 ° C. for 3 hours to obtain an alkoxysilicate hydrolyzate resin (resin 3). Shin-Etsu Silicon Co., Ltd. KBE04 5.0 parts Shin-Etsu Silicon Co., Ltd. KBM103 25.0 parts Toshiba Dow Corning SR2402 18.5 parts Toshiba Dow Corning DC3037 52.5 parts

Synthetic Example 4 In a reactor equipped with a reflux condenser and a stirrer, a hydroxyl group-containing fluororesin (manufactured by Daikin Industries, Ltd., trade name Zeffle G
K550, solid content 60%) 190 g was charged, γ-isocyanatopropylmethyldimethoxysilane 42 g and dibutyltin dilaurate 0.05 g were added with stirring, and the mixture was stirred at 40 ° C. for 4 hours to obtain a hydrolyzable silyl group having a solid content of 67%. A fluororesin (i) having was synthesized.

Synthesis Example 5 A reactor equipped with a reflux condenser and a stirrer was charged with 15 parts of propylene glycol mono-n-propyl ether and 10 parts of xylene, and an epoxy resin (Epicoat 828 manufactured by Yuka Shell Epoxy Co., epoxy equivalent 195) was charged. ) 100 copies,
Partially hydrolyzed cocondensate of phenyltrimethoxysilane (trade name: DC3074 manufactured by Toray Dow Corning, solid content 100%) 30 parts, aluminum trimethoxide 0.
Charge 15 parts and stir at 100 ° C. for 4 hours to obtain a solid content of 60.
An epoxy resin (ii) having a% hydrolyzable silyl group was synthesized.

Synthesis Example 6 Xylene 55 was added to a reactor equipped with a reflux condenser and a stirrer.
And 40 parts of isobutanol were added and mixed, and then heated to 85 ° C. with stirring. Next, 50 parts of isobutyl methacrylate, 35 parts of 2-ethylhexyl methacrylate,
A mixed solution of 15 parts of γ-methacryloxypropyltrimethoxysilane and 1.5 parts of azobisisovaleronitrile was added dropwise at 85 ° C. over 3 hours, then the temperature was raised to 90 ° C., and 2
The reaction was terminated by maintaining the time. An acrylic resin (iii) having a hydrolyzable silyl group having a solid content of 50% was synthesized.

Synthesis Example 7 A reactor equipped with a reflux condenser and a stirrer was charged with 15 parts of propylene glycol mono-n-propyl ether and 10 parts of xylene, and stirred at room temperature with 50 parts of γ-mercaptopropyltrimethoxysilane and phenyl. 20 parts of partially hydrolyzed cocondensate of trimethoxysilane (DC3074 by Toray Dow Corning; solid content 100%) and 30 parts of methyltrimethoxysilane were added and mixed, and then 9 parts of ion-exchanged water and 5 parts of isopropyl alcohol. In addition,
The reaction was carried out at 60 ° C for 3 hours. Next, 0.5 parts of triethoxyborane was added, and stirring was continued at 60 ° C. for 3 hours to obtain a polyorganosiloxane (iv) having a solid content of 60% and an active hydrogen equivalent of 510 (varnish value).

Synthesis Example 8 A reactor equipped with a reflux condenser and a stirrer was charged with 20 parts of propylene glycol mono-n-propyl ether and 10 parts of xylene, and 40 parts of γ-mercaptopropyltrimethoxysilane and phenyl while stirring at room temperature. 20 parts of trimethoxysilane partially hydrolyzed cocondensate (DC3074 manufactured by Toray Dow Corning; solid content 100%), partially hydrolyzed cocondensate of phenyltrimethoxysilane (Toray
Dow Corning DC3037; solid content 100%) 3
Add 0 parts and 10 parts of methyltrimethoxysilane,
After mixing, 7.2 parts of ion-exchanged water and 5 parts of isopropyl alcohol were added and reacted at 60 ° C. for 3 hours. Next, 0.5 part of triethoxyborane is added, and further, 60 ° C.
Stirring for 3 hours at 60% solid content, active hydrogen equivalent 68
A polyorganosiloxane (v) of 0 (varnish value) was obtained.

Preparation of Organic-Inorganic Composite Resin Components (i) to (v) obtained in the above Synthesis Examples 4 to 8 are shown in Table 1 below.
While mixing at 50 ° C. for 2 hours with each formulation, component (vi) is added at 20 ° C. and stirred until uniform to obtain organic-inorganic composite resins (4) to (6). It was

[0039]

[Table 1] Compounding of organic-inorganic composite resin 4-6

Examples 1 to 4 and Comparative Examples 1 and 2 Surface of weather-resistant steel (SMA400) defined by JIS x 3141 of 3 × 100 × 300 (mm) and having an average surface roughness of 30 μm, which has been subjected to an alumina blast treatment. Table 2 below
Each of the colored paints shown in 1 above was applied so as to have a dry film thickness of 60 μm, the back and side surfaces were sealed with an epoxy resin paint, and naturally dried for 7 days. Table 3 shows the evaluation results of the coated steel. For Example 1 and Comparative Example 2, the following colored top coating composition was further coated on the coating composition of the colored coating composition at a dry film thickness of 30 μm, dried in the same manner, and after sealing, the coated steel was evaluated.

(Colored Topcoat Paint Used in Example 1) Product name V Freon # 100H manufactured by Dainippon Paint Co., Ltd.
(Fluorine resin) White coating (colored top coating used in Comparative Example 2) 100 parts of polyvinyl butyral resin, 567 parts of isopropyl alcohol, and 23 parts of titanium dioxide were mixed and dispersed to obtain a colored top coating.

Examples 5 to 6 and Comparative Example 3 3 × 100 exposed to the outside for 5 years without treatment and having floating rust
The surface of the weather resistant steel (SMA400) specified in JIS G3141 of × 300 (mm) was lightly removed by floating brush with a wire brush, and then each of the colored paints shown in Table 2 below had a dry film thickness of 60 μm. After painting, the back and side surfaces were sealed with an epoxy resin paint and air-dried for 7 days. Table 3 shows the evaluation results of the coated steel.

Comparative Example 4 The same weather resistant steel (SMA40 as used in Example 1).
Table 3 shows the results of evaluation of the surface 0) without coating at all.

[0044]

[Table 2]

1) Polyvinyl butyral resin: manufactured by Hoechst, trade name Mobitar B60H (solid content 100%) 2) Epoxy resin (solid content 100%): epoxy equivalent 4
50 (Curing agent: Polyamide with amine value of 75 mgKOH / g 65
Part / epoxy resin 100 parts)

[0046]

[Table 3] Evaluation results

3) Unit is g / m ² / day / 50 μm 4) Gloss retention rate (%) after 300 hours of sunshine weather meter 5) Appearance of coating film 5 years after exposure to rural areas 6) Salt spray test 1000 hours 7 ) 1 mm cross-cut cellophane tape (registered trademark) peeling test (J
IS K5600-5-6) 8) Appearance of the coating film after 5 years exposure in the rural area (cross-cut portion) ○: Almost no flow rust △: There is a slight flow rust ×: Dark flow rust is conspicuous XX: Flow rust Is significantly
The coating film is not visible 9) Situation of rust under the coating film after 5 years exposure in the rural area (after peeling the coating film) ○: Dense and uniform rust △: Some pitting corrosion is observed ×: Layered rust or no rust XX: Lots of floating rust and easy to remove

By the method of the present invention, protective rust is formed at an early stage, corrosion resistance and weather resistance are maintained for a long period of time, and further, it is possible to prevent corrosion of weather-resistant steel, which is capable of arbitrary coloring and has a reduced number of steps. .

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09D 183/04 C09D 183/04 C23F 11/00 C23F 11/00 A (72) Inventor Hironori Tanabe Tochigi 8-15 F-term, Asahi-cho, Nishinasuno-machi, Nasu-gun (Reference) 4J038 CC021 CC071 CD091 CD101 CD111 CD121 CD131 CF021 CF031 CG001 CG011 CG141 CG171 CH031 CH041 CH071 DB001 DB061 DB071 DL021 DL031 GA15 HA216 HA246 HA08 HA03 HA05 HA476 HA476 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA376 HA336 PC02 4K062 AA01 BA14 BC12 BC16 BC21 FA12 GA01

Claims (9)

[Claims] 1. The following components, (1) none, on the surface of weather resistant steel:
Machine resin and / or organic-inorganic composite resin, (2) the inorganic resin
0.5 to 30 relative to fat or organic-inorganic composite resin solids
Parts by mass of NiSO_Four, NiCO₃, Ni₃(PO_Four)₂, Ni
(NO₃)₂, CuO, Cu₃(PO_Four)₂, AlPO_Four, A
l₂(M_oO_Four)₃And CuCO₃Cu (OH)₂A group of
A first compound selected from (3) the inorganic resin or
0.5 to 25 parts by mass based on the solid content of the organic-inorganic composite resin
Of H₃[PW₁₂O₄₀] ・ NH₂O, H_Four[SiW₁₂O₄₀]
・ NH₂O, H₃[PMo ₁₂O₄₀] ・ NH₂O, Na₃[P
Mo₁₂O₄₀] ・ NH₂O, H₃[PW_12-xMo_xO_{Four 0}] ・
nH₂O (0 <x <12), H_Four[SiMo₁₂O₄₀] ・ N
H₂O, phosphoric acid, nitric acid, molybdic acid, tungstic acid
And a second compound selected from the group consisting of boric acid, and
(4) For the solid content of the inorganic resin or organic-inorganic composite resin
And containing 2 to 40 parts by weight of a colorant,
Accelerated weathering test Sunshine weather meter irradiation 30
The gloss retention after 0 hours is 80% or more, and at 25 ° C
Water vapor transmission rate is 3-100g / m²/ Day / 50 μm
And a dry film thickness of 50 to 90 μm
A method for preventing corrosion of weather-resistant steel, which comprises forming a coating film. 2. The inorganic resin is represented by the general formula R ¹ _n Si (OR ² ) _4-n [wherein R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is
It is an alkyl group having 1 to 5 carbon atoms, and n is 0 or 1. ] The anticorrosion method according to claim 1, which is a hydrolysis-condensation product of an alkyl silicate represented by 3. The organic-inorganic composite resin comprises a hydrolyzed condensate of a fluororesin, an epoxy resin or an acrylic resin having a hydrolyzable silyl group, and a general formula R ¹ _n Si (OR ² ) _4-n [wherein , R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is
It is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2. ] The anticorrosion method according to claim 1, which is a mixture of the organosilane represented by the above formula or a partial hydrolysis-condensation product thereof, or a partial hydrolysis-condensation product of both. 4. The anticorrosion method according to claim 1, further comprising a silane coupling agent. 5. The anticorrosion method according to claim 1, further comprising a pollution-free rust preventive pigment. 6. The anticorrosion method according to claim 1, wherein the weather resistant steel is a weather resistant steel having rust obtained by removing only floating rust. 7. The weather resistant steel according to claim 1, further comprising a colored top coating film having a gloss retention of 80% or more after 300 hours of irradiation of the accelerated weather resistance test sunshine weather meter on the colored coating film. Anticorrosion method. 8. The colored top coating film has a general formula R ¹ _n Si (OR ² ) _4-n [wherein R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is
It is an alkyl group having 1 to 5 carbon atoms, and n is 0 or 1. ] The anticorrosion method of Claim 7 containing the inorganic resin which consists of the hydrolysis-condensation product of the alkyl silicate shown by these. 9. The colored top coating film comprises a hydrolyzate of a fluororesin, an epoxy resin or an acrylic resin having a hydrolyzable silyl group, and a general formula R ¹ _n Si (OR ² ) _4-n [wherein R ¹ is an organic group having 1 to 8 carbon atoms, and R ² is
It is an alkyl group having 1 to 5 carbon atoms, and n is 1 or 2. ] The organic-inorganic composite resin which consists of organosilane or its partial hydrolysis-condensation product shown by these is contained.
Anticorrosion method described.