JP3023392B2 - Painted article and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated article of a metal base material and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, as a coated article of a steel sheet such as stainless steel or a non-ferrous metal such as aluminum, an article formed with an organic coating or a sheet formed with a water glass coating is known. However, most have a colored layer. Recently, there has been a demand for a coated article that retains the metal texture and overcomes the disadvantage of metal corrosion, which is a disadvantage. Reflecting those needs, some are coated with a fluorine-based clear-coated stainless steel base material or a water glass-based coating material, but they are not sufficient in terms of long-term durability.

[0003]

Therefore, when a coating material having sufficient long-term durability was examined, it was found that the first and second coating materials having transparency as described later in detail are preferable. I found it. However, it is difficult to directly adhere a coating made of such a coating material to a metal-based substrate such as stainless steel or aluminum for a long time. The use of a normal primer to coat the coating material was also examined, but in the case of leaving the feel of the material of the base material, there was a problem that the primer was exposed to ultraviolet rays and the primer was deteriorated.

Accordingly, the present invention is to provide a maintenance-free coated article which retains the texture of the metal base material, secures corrosion resistance, weather resistance, stain resistance and the like for a long period of time, and provides such a maintenance-free coated article. It is an object to provide a method for manufacturing an article.

[0005]

Means for Solving the Problems The inventors of the present invention have intensively studied a method for solving the problems of the above-mentioned conventional coated articles, and as a result, after degreasing and cleaning the metal base material, cleaning the surface and performing a chemical conversion treatment. In the presence of water and colloidal silica (colloidal silica) dispersed in an organic solvent or water, or in the presence of an organic solvent and water, a coating material obtained by hydrolysis and condensation polymerization of alkoxysilane (hereinafter, referred to as " A coating comprising a silica-dispersed oligomer in which alkoxysilane is partially hydrolyzed in colloidal silica dispersed in an organic solvent or water, a silanol group-containing organopolysiloxane, and a catalyst. It was found that coating and curing the material (hereinafter referred to as "second coating material") solved all the problems. It has led to the completion of the invention.

That is, in the coated article of the present invention, a chemical conversion coating is formed as a first layer on a metal substrate, and a second layer is formed on the first layer by the following general formula: R ′ _m Si (OR ") _4-m ... [where R 'is a methyl group, an ethyl group or a phenyl group, R" is an alkyl group having 1 to 4 carbon atoms, and m is 0, 1 or 2. " Of the compound I and the colloidal silica represented by the formula (I) are hydrolyzed, polycondensed, and polymerized with a silanol-terminated prepolymer to form a film. The coating comprises a first coating of the prepolymer.
And is transparent.

In the coated article of the present invention, a chemical conversion coating film is formed as a first layer on a metal substrate, and a second layer formed on the first layer has a transparency comprising a silicon compound shown below. Is formed. That is,
This silicon compound is composed of a second coating material containing the following components A, B and C as essential components. (A) General Formula R ¹ _n SiX _{4-n wherein} R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and n is an integer of 0 to 3 , X represents a hydrolyzable group. ] An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane represented by the formula (1) in colloidal silica dispersed in an organic solvent or water. (B) Average composition formula R ² _a Si (OH) _b O _{(4-ab) / 2} ... wherein R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. And a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. And a polyorganosiloxane containing a silanol group in the molecule. (C) a catalyst.

According to the method for producing a coated article of the present invention, a chemical conversion coating is formed as a first layer on a metal substrate, and then a second chemical conversion coating is formed.
As the layer, the first coating material is applied and cured to form a transparent film. The method for producing a coated article of the present invention further comprises:
After forming the chemical conversion coating as the first layer, the second coating material is applied and cured as the second layer to form a transparent coating.

The chemical conversion coating used in the present invention is:
Refers to a film obtained by ordinary chromate treatment and phosphate conversion treatment. Chemical conversion coating, chromate chromate,
There are chromate phosphate, zinc phosphate, calcium phosphate, iron phosphate and the like. In particular, for stainless steel and aluminum substrates,
Chromate treatment is preferred, and in particular, chromate treatment containing silica powder or colloidal silica is preferred to ensure long-term adhesion to the silicon compound film used in the present invention.
In addition, trivalent chromium ions may be contained in all chromium components, but it is preferable that Cr ³⁺ / Cr ⁶⁺ ≦ 1. Although some water-soluble organic resins may be contained, the amount of the organic resin added is 5
% Or less is good. If the amount exceeds 5%, the stability of the chromate solution is deteriorated, and in terms of performance, the adhesion is lowered and the long-term durability is adversely affected. The chemical conversion coating preferably has a total chromium content of 5 mg / m ² or more. If less than 5 mg / m ² ,
It adversely affects the adhesion to the silicon compound film and the corrosion resistance. The treatment method is not particularly limited, such as immersion treatment and coating treatment. However, if the treatment amount is excessively large, coloring occurs, and the silicon compound serving as the second layer becomes noticeable even when applied. Therefore, the treatment amount is preferably 30 mg / m ² or less. The temperature at that time may be, for example, room temperature. Drying of the treated film after application may be performed at room temperature, but is preferably performed at 50 ° C. or higher from the viewpoint of workability. Preferably, 80 ° C to 120 ° C is good.

The chemical conversion coating alone has no water resistance for a long period of time (for example, Cr ⁶⁺ flows out) and has insufficient corrosion resistance. After forming the chemical conversion coating, a silicon compound coating is applied as the second layer. Materials for obtaining the silicon compound coating used in the present invention will be described below. The first coating material is an essential component of a silanol-terminated prepolymer obtained by hydrolyzing and condensing a raw material comprising at least the compound I of the compound I and colloidal silica represented by the above general formula. is there. This coating material is, for example, the following component a,
A mixture containing b and c as main components undergoes hydrolysis and polycondensation reaction, the weight average molecular weight Mw is 500 to 3000 in terms of polystyrene, and the molecular weight distribution Mw / Mn is 1.1 to 3.0 (Mn is It is a coating material containing a prepolymer of terminal silanol having a number average molecular weight) as an essential component. This coating material has a pH value of 3.8 to
The stability is better when adjusted to 6.0. (A) 20 to 200 parts by weight of a silicon compound and / or colloidal silica represented by n = 0 in the above general formula. (B) 100 parts by weight of a silicon compound represented by n = 1 in the above general formula. (C) 0 to 80 parts by weight of a silicon compound represented by n = 2 in the above general formula.

The first coating material (inorganic coating material composition) used in the present invention is prepared by, for example, diluting the above-mentioned raw material silicon compound components a, b and c with an appropriate solvent, and adding a curing agent and a catalyst thereto. It is prepared by adding a necessary amount to carry out hydrolysis and polycondensation to form a prepolymer. The molecular weight of the prepolymer is
The weight average molecular weight Mw is 500 to 30 in terms of polystyrene.
And the molecular weight distribution Mw / Mn (Mn is the number average molecular weight) must be 1.0 to 3.0, and preferably,
Mw = 600-3000, and Mw / Mn = 1.2-
1.8. When the weight average molecular weight and the molecular weight distribution of the prepolymer are smaller than the above ranges, the curing shrinkage at the time of polycondensation tends to increase, and the coating film tends to crack after baking. Further, when the value is larger than the above range, the reaction is too slow to be hardened, or becomes a soft film even when hardened,
The leveling property of the coating film tends to be very poor.

The colloidal silica is obtained by dispersing a particulate silica component in an organic solvent such as water or methanol, or a mixed solvent thereof, but the particle size, solvent type and the like are not particularly limited. When colloidal silica is used as the component a, the mixing ratio is a part by weight including a dispersion medium. As the curing agent used in the present invention, for example, water is used, and the amount is not particularly limited, but is preferably not more than 45%, more preferably not more than 25% by weight in the coating material composition. Is good.

The catalyst used in the present invention is not particularly limited. For example, acidic catalysts such as an inorganic acid such as hydrochloric acid, phosphoric acid and sulfuric acid and a dilute solution of an organic acid such as formic acid, acetic acid and chloroacetic acid will be described later. A basic catalyst or the like can be used alone or in combination of two or more. When silica sol is used as the component a, the silica sol exhibits acidity, which serves as a catalyst, so that nothing needs to be added as a catalyst.

The inorganic coating material composition used in the present invention can be used stably within the above-mentioned molecular weight range by adjusting the pH value to 3.8 to 6.0. If the pH value is outside the above range, the stability of the coating material composition is poor, so that the usable period from the time of preparing the paint may be limited. Here, the method of adjusting the pH value is not particularly limited. For example, when the pH value becomes less than 3.8 at the time of mixing the raw materials of the coating material, the pH value is adjusted using a basic reagent such as ammonia. The pH may be adjusted to a value within the range, and the pH is adjusted to 6.0.
In the case where the temperature exceeds the limit, it may be adjusted using, for example, an acidic reagent such as hydrochloric acid. In addition, depending on the pH, if the reaction does not proceed with a low molecular weight and it takes time to reach the above molecular weight range, the coating material may be heated to accelerate the reaction, or the pH value may be adjusted with an acidic reagent. After the reaction is advanced by lowering the pH value, the pH value may be returned to a predetermined value with a basic reagent.

As mentioned above, the basic catalyst is added to the coating material which has been adjusted in pH or not adjusted in pH at least at the time of use, that is, before or at the time of use. By doing so, the condensation reaction can be promoted and the number of crosslinking points in the coating film can be increased, so that a coating film having good crack resistance can be obtained stably. In addition, since the curing reaction can be shortened or the curing temperature can be reduced by promoting the crosslinking reaction, there is an effect that it is economical and can be applied to a substrate that can only be baked at a low temperature. Examples of the basic catalyst include amines (for example, triethanolamine and the like),
Aminosilanes (for example, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, etc.)
And inorganic acids (eg, hydrochloric acid, nitric acid, phosphoric acid, etc.) and organic acids (eg, formic acid, acetic acid, propionic acid, etc.)
Of ammonia, trimethylamine, triethylamine,
Salts such as n-butylamine and the like, and metathesis salts of salts of inorganic acids and organic acids with quaternary ammonium salts, etc., are not particularly limited in type and amount.

In addition to the above-mentioned components, the inorganic coating material composition prepared by the above-described method may contain various coloring agents and fillers other than the above-mentioned silica sol (for example, alumina sol, fumed silica, etc.). One or more kinds of various additives such as an inorganic filler), a diluting solvent, a thickener, a surfactant, and an ultraviolet absorber may be added. Examples of the diluting solvent include alcohols such as methanol, ethanol, and isopropanol (also referred to as IPA); ethyl cellosolve, butyl cellosolve, ethylene glycol, ethylene glycol monomethyl ether, and the like. These may be used alone or in combination.

In the present invention, the coating method of the inorganic coating material composition includes, for example, spray coating, roll coating, flow coater coating, and dip coating.
There is no particular limitation. The conditions for drying and baking after the coating are not particularly limited, but it is preferable to perform the drying at about 60 to 200 ° C. On the other hand, when the proportion of the component a is less than 20 parts by weight or more than 200 parts by weight, there is a problem that crack resistance is poor. When the amount of the component c exceeds 80 parts by weight, the coating film is too soft to be practical.

Next, the second coating material will be described. This coating material contains the following components A, B and C as essential components. (A) General Formula R ¹ _n SiX _{4-n wherein} R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and n is an integer of 0 to 3 , X represents a hydrolyzable group. ] An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane represented by the formula (1) in colloidal silica dispersed in an organic solvent or water. (B) Average composition formula R ² _a Si (OH) _b O _{(4-ab) / 2} ... wherein R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. And a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. And a polyorganosiloxane containing a silanol group in the molecule. (C) a catalyst.

The silica-dispersed oligomer of the component A used in the present invention is a main component of a base polymer having a hydrolyzable group (X) as a functional group which is subjected to a curing reaction when forming a film. This is achieved by adding one or more hydrolyzable organosilanes represented by the general formula to colloidal silica dispersed in an organic solvent or water (including a mixed solvent of an organic solvent and water), and adding the colloidal silica to the colloidal silica. The hydrolyzable organosilane is obtained by partially hydrolyzing the hydrolyzable organosilane with water or separately added water.

R ¹ in the hydrolyzable organosilane represented by the general formula represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, such as a methyl group, an ethyl group, a propyl group and a butyl group. Alkyl groups such as a group, a pentyl group, a hexyl group, a heptyl group, and an octyl group; cycloalkyl groups such as a cyclopentyl group and a cyclohexyl group; aralkyl groups such as a 2-phenylethyl group, 2-phenylpropyl group, and 3-phenylpropyl group Aryl groups such as phenyl group and tolyl group; alkenyl groups such as vinyl group and allyl group; halogens such as chloromethyl group, γ-chloropropyl group, 3,3,3-trifluoropropyl group and the like; Substituted hydrocarbon group; and γ-methacryloxypropyl group, γ-glycidoxypropyl group, 3,4
And substituted hydrocarbon groups such as an epoxycyclohexylethyl group and a γ-mercaptopropyl group. Among these, an alkyl group having 1 to 4 carbon atoms and a phenyl group are preferable in terms of ease of synthesis or availability.

As the hydrolyzable group X, an alkoxy group,
Acetoxy group, oxime group [-ON = C (-R ')-
R], an enoxy group [-OC (-R) = C (-R ")-
R ′], an amino group, an aminoxy group [—O—N (—R) —
R '], an amide group [-N (-R')-CO-R] [where R, R 'and R "each independently represent, for example, hydrogen or a monovalent hydrocarbon group] Alkoxy groups are preferred because they are easily available and easy to prepare a silica-dispersed oligomer solution.

Examples of such hydrolyzable organosilanes include mono-, di-, tri-, and tetra-functional alkoxysilanes and acetoxysilanes in which n in the general formula is an integer of 0 to 3. , Oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, amidosilanes and the like. Alkoxysilanes are preferred because they are easily available and easy to prepare a silica-dispersed organosilane oligomer solution.

Particularly, tetramethoxysilane, tetraethoxysilane and the like can be exemplified as n = 0 tetraalkoxysilane, and methyltrimethoxysilane, methyltriethoxysilane, methyltriisosilane can be exemplified as n = 1 organotrialkoxysilane. Propoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,
3,3,3-trifluoropropyltrimethoxysilane and the like can be exemplified. Examples of the diorganodialkoxysilane having n = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane,
Examples include diphenyldiethoxysilane and methylphenyldimethoxysilane. Examples of the triorganoalkoxysilane having n = 3 include trimethylmethoxysilane, trimethylethoxysilane, trimethylisopropoxysilane, and dimethylisobutylmethoxysilane. Further, an organosilane compound generally called a silane coupling agent is also included in the alkoxysilanes.

It is preferable that 50 mol% or more of the hydrolyzable organosilane represented by these general formulas is a trifunctional one represented by n = 1, more preferably 60 mol% or more. , Most preferably at least 70 mol%. If the content is less than 50 mol%, a sufficient coating film hardness cannot be obtained, and the drying curability may be inferior. A
The colloidal silica in the component is essential for increasing the hardness of the cured film of the second coating material (coating composition) used in the present invention. As such colloidal silica, water-dispersible or non-aqueous organic solvent dispersible colloidal silica such as alcohol can be used. Generally, such colloidal silica contains 20 to 50% by weight of silica as a solid content, and the amount of silica can be determined from this value. When water-dispersible colloidal silica is used, water present as a component other than the solid content can be used for hydrolyzing the component A organosilicon compound. These are usually made from water glass, but such colloidal silica is readily available commercially. Further, the organic solvent-dispersed colloidal silica can be easily prepared by replacing water of the water-dispersible colloidal silica with an organic solvent. Such an organic solvent-dispersed colloidal silica can be easily obtained as a commercial product similarly to the water-dispersed colloidal silica. The type of the organic solvent in which the colloidal silica is dispersed is, for example, methanol, ethanol, isopropanol, n
Lower aliphatic alcohols such as butanol and isobutanol; ethylene glycol derivatives such as ethylene glycol, ethylene glycol monobutyl ether and ethylene glycol monoethyl ether; derivatives of diethylene glycol such as diethylene glycol and diethylene glycol monobutyl ether; and diacetone alcohol. And one or more selected from the group consisting of these can be used. Toluene in combination with these hydrophilic organic solvents,
Xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can also be used.

In the component A, colloidal silica is contained in a range of 5 to 95% by weight as a silica component. More preferably from 10 to 90% by weight, most preferably from 20 to 85% by weight.
% By weight. If the content is less than 5% by weight, a desired coating hardness cannot be obtained, and if it exceeds 95% by weight, it is difficult to uniformly disperse the silica, which may cause inconvenience such as gelling of the component A.

The silica-dispersed oligomer of the component A can be usually obtained by partially hydrolyzing a hydrolyzable organosilane in water-dispersed colloidal silica or organic solvent-dispersed colloidal silica. The amount of water used relative to the hydrolyzable organosilane is preferably 0.001 to 0.5 mol of water per 1 mol of the hydrolyzable group (X). If the amount is less than 0.001 mol, a sufficient partial hydrolyzate cannot be obtained, and if it exceeds 0.5 mol, the stability of the partial hydrolyzate may deteriorate. The method for performing the partial hydrolysis is not particularly limited, and the hydrolyzable organosilane and colloidal silica may be mixed and a necessary amount of water may be added and blended. At this time, the partial hydrolysis reaction proceeds at room temperature. You may heat to 60-100 degreeC in order to accelerate a partial hydrolysis reaction. In order to further promote the partial hydrolysis reaction, hydrochloric acid, acetic acid, halogenated silane, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluene Organic acids such as sulfonic acid and oxalic acid and inorganic acids may be used as the catalyst.

In order to obtain a stable performance over a long period of time, the pH of the solution A should be 2.0 to 7.0, preferably pH 2.0.
The pH is preferably adjusted to 5 to 6.5, more preferably to 3.0 to 6.0. If the pH is out of this range, the long-term deterioration of the performance of the component A may be remarkable particularly when the amount of water used is 0.3 mol or more per 1 mol of X. When the pH of the component A is out of this range, if it is more acidic than this range, it may be adjusted by adding a basic reagent such as ammonia or ethylenediamine. It may be adjusted using an acidic reagent such as However, the adjustment method is not particularly limited.

The silanol group-containing polyorganosiloxane as the component B is an important component that characterizes the present invention.
Such a B component can be represented by the above average composition formula. In the formula, as R ² , the same as R ¹ in the above formula are exemplified, and preferably, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a vinyl group, a γ-glycidoxypropyl group, a γ- A substituted hydrocarbon group such as a methacryloxypropyl group, a γ-aminopropyl group and a 3,3,3-trifluoropropyl group, more preferably a methyl group and a phenyl group. Further, in the formula, a and b are numbers satisfying the above relationship, respectively, and if a is less than 0.2 or b exceeds 3, there is a problem that cracks occur in the cured film,
When a is more than 2 and 4 or less, or b is 0.000
If it is less than 1, curing does not proceed well.

Such a silanol group-containing polyorganosiloxane may be, for example, methyltrichlorosilane, dimethyldichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, or a mixture of one or more of alkoxysilanes corresponding thereto. It can be obtained by hydrolysis with a large amount of water by a known method. When a silanol group-containing polyorganosiloxane is hydrolyzed by a known method using alkoxysilane, a small amount of an unhydrolyzed alkoxy group may remain. That is, a polyorganosiloxane in which a silanol group and a trace amount of an alkoxy group coexist may be obtained, but in the present invention, such a polyorganosiloxane may be used.

The curing catalyst, which is the component C of the present invention, promotes the condensation reaction between the components A and B to cure the coating. Examples of such a catalyst include metal salts of carboxylic acids such as alkyl titanates, tin octylate and dibutyltin dilaurate and dioctyltin dimaleate; amines such as dibutylamine-2-hexoate, dimethylamine acetate and ethanolamine acetate; Salts; quaternary ammonium salts of carboxylic acids such as tetramethylammonium acetate; amines such as tetraethylpentamine; N-β-aminoethyl-γ-aminopropyltrimethoxysilane; N-β-aminoethyl-γ-amino Amine-based silane coupling agents such as propylmethyldimethoxysilane; p-toluenesulfonic acid, phthalic acid,
Acids such as hydrochloric acid; aluminum compounds such as aluminum alkoxide and aluminum chelate; alkali catalysts such as potassium hydroxide; titanium compounds such as tetraisopropyl titanate, tetrabutyl titanate and titanium tetraacetylacetonate; methyltrichlorosilane, dimethyldichlorosilane, trimethyl Although there are halogenated silanes such as monochlorosilane, etc., there is no particular limitation as long as it is effective for the condensation reaction with the component A and the component B in addition to the catalyst.

The mixing ratio of the component A and the component B is 99 to 1 part by weight of the component A to 99 to 1 part by weight of the component A,
More preferably, the B component is 9 to 5 to 95 parts by weight of the A component.
5 to 5 parts by weight, most preferably 10 to 90 parts by weight of component A and 90 to 10 parts by weight of component B. However, the total of the components A and B is 100 parts by weight. If the component A is less than 1 part by weight, the curability at room temperature is inferior, and sufficient film hardness cannot be obtained. On the other hand, if the component A exceeds 99 parts by weight, the curability is unstable and a good coating film is obtained. May not be possible.

The addition amount of the component C is preferably 0.0001 to 10 parts by weight, more preferably 0.0005, based on 100 parts by weight of the total of the components A and B.
-8 parts by weight, most preferably 0.0007-5 parts by weight. If the amount of the component C is less than 0.0001 part by weight, the composition may not be cured at room temperature, and if it exceeds 10 parts by weight, heat resistance and weather resistance may be deteriorated.

The hydrolyzable group contained in the silica-dispersed oligomer of the component A and the silanol group of the component B can be heated at room temperature or low temperature (for example, at a temperature of 100 ° C. or lower) in the presence of the curing catalyst of the component C. The condensation reaction forms a cured film. Therefore, like the moisture-curing type coating composition, the second coating material (coating composition) used in the present invention is hardly affected by humidity even when cured at room temperature. In addition, a heat treatment can promote a condensation reaction to form a cured film.

The inorganic coating material prepared by the above-mentioned method includes, as necessary, various coloring agents, fillers other than the above-mentioned silica sol (inorganic fillers such as alumina sol and fumed silica), in addition to the above-mentioned components. Diluent solvent, thickener,
One or more kinds of various additives such as a surfactant and an ultraviolet absorber may be added. Examples of the diluent include alcohols such as methanol, ethanol, and isopropanol; ethyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, and the like. These may be used alone or in combination. Further, in combination with these hydrophilic organic solvents, toluene, xylene, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl isobutyl ketone, methyl ethyl ketoxime and the like can also be used.

As a method for storing the coating material,
It is common to take three packing forms in which the A, B and C components are stored separately, but separate the mixed components of the A and C components and the B component into two packing forms and mix both at the time of use. Alternatively, all the components may be mixed and stored in a single container in one package. This coating material can be coated by an ordinary application method, and for example, various application methods such as brushing, spraying, dipping, and flow can be selected. Curing conditions are 5 ° C or higher,
It is preferably 200 ° C. or lower, more preferably 10 ° C. or higher and 150 ° C. or lower. If it is less than 5 ° C., it is difficult to cure,
If the temperature exceeds ℃, foaming may occur. The coating thickness of the second layer is preferably 3 microns or more after curing. If it is less than 3 microns, pinholes are easily formed and the anticorrosion property may be deteriorated.

The coated article of the present invention or the coated article obtained by the manufacturing method of the present invention retains the texture of a steel plate such as stainless steel or a non-ferrous metal such as aluminum.
It is maintenance-free with long-term corrosion protection, weather resistance, stain resistance, etc. For this reason, such a coated article is used, for example, as a member for an exterior wall material, a roof material, a rain gutter, or the like.

[0037]

According to the present invention, a chemical conversion coating is formed as a first layer on a surface of a metal base material, and a transparent coating made of the first or second coating material is formed thereon as a second layer, thereby preventing corrosion. , Weather resistance, stain resistance, etc. are ensured, and maintenance free. In addition, the underlying metal can be seen through the transparent film, so that a metallic feel can be obtained.

[0038]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples.
Hereinafter, "parts" means "parts by weight". First, the coating material used for painting and its components will be described. (C-1) 100 parts of methyltrimethoxysilane, 20 parts of tetraethoxysilane, 150 parts of IPA organosilica sol (trade name “OSCAL1432” manufactured by Catalyst Chemicals, Inc.),
40 parts of dimethyldimethoxysilane and 100 parts of isopropyl alcohol (IPA) were mixed, and 200 parts of H ₂ O was added and stirred. The molecular weight was adjusted to Mw = 1200 in a 60 ° C. thermostat. This solution is called C-1.
The molecular weight was measured by GPC (gel permeation chromatography) using a calibration model name HLC8020 (manufactured by Tosoh Corporation) to create a calibration curve with standard polystyrene.

The following molecular weights were also measured using this apparatus. (C-2) 3 parts of fumed silica (trade name "Aerosil 200" manufactured by Nippon Aerosil Co., Ltd.) as a filler is added to 100 parts of the liquid C-1 and dispersed with a Glenmill to prepare a coating liquid C-2. Obtained. (C-3) IPA-ST (isopropyl alcohol-dispersed colloidal silica sol: particle diameter of 10 to 20 mμ, solid content of 30%, H ₂ O of 0.5%, Nissan in a flask equipped with a stirrer, heating jacket, condenser and thermometer) 100 parts, methyltrimethoxysilane 6
8 parts, 18 parts of dimethyldimethoxysilane, 2.7 parts of water,
0.1 part of acetic anhydride was charged, and a partial hydrolysis reaction was carried out at a temperature of 80 ° C. for about 3 hours while stirring, followed by cooling to obtain an A component. This had a solid content of 36% when left at room temperature for 48 hours. Preparation conditions of component A: number of moles of water per mole of hydrolyzable group: 1 × 10 ^-1 · silica content of component A: 40.2% · mole% of n = 1 hydrolyzable organosilane: 77 mol% In a flask equipped with a stirrer, a heating jacket, a condenser, a dropping funnel and a thermometer, 220 parts (1 mol) of methyltriisopropoxysilane and toluene 15 were added.
The mixture with 0 parts was weighed, and 108 parts of a 1% aqueous hydrochloric acid solution was added dropwise to the mixture over 20 minutes to hydrolyze methyltriisopropoxysilane. Stop stirring 40 minutes after dropping,
A mixed solution of water and isopropyl alcohol in the lower layer containing a small amount of hydrochloric acid separated into two layers is separated, then the remaining hydrochloric acid of the resin solution of toluene is removed by washing with water, and toluene is further removed under reduced pressure. After dilution with alcohol, a component B was obtained as a 40% isopropyl alcohol solution of a silanol group-containing organopolysiloxane having an average molecular weight of about 2,000. (C-4) Fluorine clear (Lumiflon-based) (trade name “V Freon 2000 clear”) manufactured by Dainippon Paint Co., Ltd. is referred to as C-4. (C-5) Water glass ceramic coating agent (CR
M-700 (S) manufactured by Okuno Pharmaceutical Co., Ltd., undiluted solution pH =
12.0) is designated C-5. (C-6) Fluorine clear (Kyner system) (trade name “Precolor No. 8300 Clear”) manufactured by NOF Corporation is referred to as C-6.

Examples 1 to 6 In this example, the first coating material is used. In carrying out, a stainless steel base material (SUS304) with a hairline finish manufactured by Nissin Steel Co., Ltd. was used. Degreasing of the substrate was performed by alkali degreasing. Thereafter, the substrate was subjected to a chemical conversion treatment shown in Table 1 after being washed with ion-exchanged water, washed with ion-exchanged water, and then heated at
And dried.

[0041]

After the chemical conversion treatment, a coating (inorganic coating) was applied to obtain a coated article. In Examples 1 to 3, the coating material (C-1) was applied by spraying, the applied film thickness was 8 μm, and after setting for 5 minutes, baking was performed at 180 ° C. for 20 minutes. In Examples 4 to 6, the same treatment was performed using the coating material (C-2). -Examples 7 to 9-The examples here are the cases where the second coating material is used.

Using component A and component B of C-3, component A
5 parts and 35 parts of the B component were mixed with 3 parts of N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane as a catalyst (component C) to prepare a second coating material. This second coating material was applied by spraying to a substrate treated in the same manner as in Examples 1 to 6, and the applied film thickness was 8 μm.
After setting for 5 minutes, baking was performed at 60 ° C. for 20 minutes to obtain a coated article.

Comparative Example 1 A coated article was obtained in the same manner as in Example 1 except that the chemical conversion treatment was not performed. -Comparative Example 2-Chromate treatment N shown in Table 1 was applied to a substrate in the same manner as in Example.
o. After applying K-3, spray the coating material of C-4 instead of performing inorganic coating to a thickness of 25 μm.
After setting for 5 minutes,
Baking was performed at 200 ° C. for 10 minutes to obtain a coated article.

Comparative Example 3 Chromate treatment N shown in Table 1 was applied to a substrate in the same manner as in Example.
o. After applying K-3, instead of performing inorganic coating, the substrate is subjected to a preliminary heat treatment (230 ° C. × 30 minutes),
The coating material of C-5 was applied by spraying so as to have a thickness of 20 μm, and then baked at 230 ° C. for 20 minutes to obtain a coated article.

Comparative Example 4 Chromate treatment N shown in Table 1 was applied to a substrate in the same manner as in Example.
o. After applying K-3, instead of performing inorganic coating, spray a C-6 coating material to a film thickness of 20 μm.
After setting for 5 minutes,
Baking was performed at 240 ° C. for 10 minutes to obtain a coated article.

The coated article thus obtained was examined for adhesion, corrosion resistance and weather resistance, and the results are shown in Table 2. The adhesion was immersed in boiling water for 7 hours, air-dried, and confirmed with an adhesive tape (cellophane tape) within 3 hours. The anticorrosion property was visually evaluated after 2,000 hours of the salt spray test.

The weather resistance was measured using an eye super UV tester.
The following table shows one cycle (8 hours + 4 hours = 12 hours as one cycle), and the situation after performing the UV irradiation time up to 1000 hours was evaluated. Test conditions Time 8 hours 4 hours UV irradiation Available (100 mW / cm ² ) None Temperature 63 ° C 35 ° C Humidity 50% 90% or more (with condensation)

[0049]

[Table 2]

As shown in Table 2, the formation of the chemical conversion layer as the first layer and the formation of the first or second coating material as the second layer on the metal base material enables the adhesion to be improved. A coated article excellent in all properties, corrosion resistance and weather resistance can be obtained, but if a chemical conversion treatment layer is not formed or if a film composed of the first and second coating materials is not formed, One or more of the three properties are inferior.

[0051]

According to the present invention, it is possible to provide a maintenance-free coated article which retains the texture of a metal-based substrate, secures corrosion resistance, weather resistance, stain resistance, and the like for a long period of time.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI C09D 183/06 C09D 183/06 (72) Inventor Junichi Yoshimoto 1048 Ojidoma, Kadoma, Osaka Pref. Matsushita Electric Works, Ltd. (72) Inventor Hideaki Minagawa Matsushita Electric Works Co., Ltd., 1048, Kadoma, Kadoma, Osaka Prefecture (72) Inventor Eiji Honda Inventor, Matsushita Electric Works, 1048, Kadoma, Kadoma, Osaka, Japan (56) References JP-A-63-130170 (JP, A) JP-A-61-162563 (JP, A) JP-A-3-31380 (JP, A) JP-A-3-197548 (JP, A) JP-A-58-101153 (JP, A) JP-A-60-225672 ( JP, A) JP-A-3-275348 (JP, A) JP-A-3-31380 (JP, A) JP-B-53-5042 (JP, B2) European Patent Application 430156 (EP, A2) (58) ) Surveyed field (Int.Cl. ⁷ , DB name) B05D 7/14 B05D 1/36 B05D 3/10 B05D 5/00 B05D 7/24 302 C09D 183/06

Claims (4)

(57) [Claims] 1. A chemical conversion coating is formed as a first layer on a metal substrate, and a second layer is formed on the first layer by the following general formula: R ′ _m Si (OR ″) _4-m . Here, R ′ is a methyl group, an ethyl group or a phenyl group, R ″ is an alkyl group having 1 to 4 carbon atoms, and m is 0, 1 or 2. The raw material comprising at least the compound I of the compound I and colloidal silica represented by the formula is hydrolyzed and polycondensed, and the weight average molecular weight (in terms of polystyrene) Mw 500 to
3000, molecular weight distribution Mw / Mn (Mn is a number average molecule
A coated article having a transparency of 1.0 to 3.0 and a silicon compound obtained by polymerizing a silanol-terminated prepolymer. 2. A chemical conversion coating film is formed as a first layer on a metal substrate, and a second layer is formed on the first layer from a coating composition containing the following components A, B and C as essential components. A coated article having a transparent coating formed thereon. (A) General Formula R ¹ _n SiX _{4-n wherein} R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and n is an integer of 0 to 3 , X represents a hydrolyzable group. ] An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane represented by the following formula in colloidal silica dispersed in an organic solvent or water. (B) Average composition formula R ² _a Si (OH) _b O _{(4-ab) / 2} ... wherein R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. And a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. ] The polyorganosiloxane which contains a silanol group in a molecule represented by these. (C) a catalyst. 3. After forming a chemical conversion coating film as a first layer on a metal base material, as a second layer, the following general formula: R ′ _m Si (OR ″) _4-m . A methyl group, an ethyl group or a phenyl group, R ″ is an alkyl group having 1 to 4 carbon atoms, and m is 0, 1 or 2. The raw material comprising at least the compound I of the compound I and colloidal silica represented by the formula is hydrolyzed and polycondensed, and the weight average molecular weight (in terms of polystyrene) Mw 500 to
3000, molecular weight distribution Mw / Mn (Mn is a number average molecule
Amount) A method for producing a coated article which forms a transparent film made of a silicon compound obtained by polymerizing a prepolymer having a terminal of silanol at a ratio of 1.0 to 3.0 . 4. After forming a chemical conversion coating film as a first layer on a metal base material, the second layer has transparency composed of a coating composition comprising the following components A, B and C as essential components. A method for producing a coated article for forming a coating. (A) General Formula R ¹ _n SiX _{4-n wherein} R ¹ represents the same or different substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms, and n is an integer of 0 to 3 , X represents a hydrolyzable group. ] An organosilane silica-dispersed oligomer solution obtained by partially hydrolyzing the hydrolyzable organosilane represented by the following formula in colloidal silica dispersed in an organic solvent or water. (B) Average composition formula R ² _a Si (OH) _b O _{(4-ab) / 2} ... wherein R ² is the same or different and is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 8 carbon atoms. And a and b are 0.2 ≦ a ≦ 2, 0.0001 ≦ b ≦ 3, and a + b, respectively.
It is a number that satisfies the relationship of <4. ] The polyorganosiloxane which contains a silanol group in a molecule represented by these. (C) a catalyst.