JP2001158969A - Metal surface treatment composition - Google Patents

Abstract

[Problem] To provide a metal such as a zinc-plated steel sheet with excellent corrosion resistance, scratch resistance and fingerprint resistance, and to prevent a change in color tone and a decrease in gloss, and a metal containing no chromium. Provide a surface treatment composition. An aqueous composition containing a water-soluble organic resin, a water-dispersible organic resin, a metal ion, an acid and an aqueous medium but not containing chromium, preferably further contains a polyhydric phenol carboxylic acid, a coupling agent, and an organic compound. An aqueous composition containing an acid or the like, which is applied to, for example, a black steel sheet to obtain a steel sheet that is excellent in corrosion resistance and the like, and has no color tone change and gloss reduction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal surface treating agent, and more particularly, to a metal surface treating agent which is particularly excellent in corrosion resistance and yellowish / greenish even though it does not contain chromium.
The present invention relates to a metal surface treatment composition capable of providing a surface treatment metal material having excellent scratch resistance and fingerprint resistance without causing a change in color tone such as whitening and low gloss.

[0002]

2. Description of the Related Art Conventionally, galvanized steel sheets such as galvanized steel sheets and zinc-aluminized steel sheets have been widely used in the fields of home appliances, automobiles and construction. In order to improve the corrosion resistance of the steel sheet, these steel sheets are subjected to a chromate coating treatment on the plating or after a chromate coating treatment.
Furthermore, it is used after applying an organic film. When applying an organic film, the chromate film also plays a role of improving the adhesion to the organic film. Also, in some cases,
So-called resin / mixed organic resin and chromate chemical
In some cases, a chromate solution is applied and used.

However, a chromate film or a film obtained by applying a resin / chromate chemical solution has excellent corrosion resistance and coating adhesion, but contains hexavalent chromium. , It is necessary to perform a special wastewater treatment, which has a disadvantage of increasing the cost. Furthermore, it was impossible to prevent the color tone of the steel sheet surface from changing to yellow or green due to chromium ions. For this reason, in order to prevent the generation of white rust on steel sheets, particularly zinc-based plated steel sheets, surface treatment techniques that do not use chromium are required. For example, a number of the following surface treatment techniques have been proposed.

[0004] JP-A-5-195244 discloses that
(A) an anionic component composed of at least four fluorine atoms and at least one element such as titanium and zirconium (for example, fluorotitanic acid represented by (TiF ₆ ^2- )); (b) cobalt and magnesium A metal surface treatment method comprising a composition containing (c) a free acid for controlling pH and (d) an organic resin but not containing chromium, such as a cationic component, has been proposed.

[0005] JP-A-9-241856 discloses that
(A) a hydroxyl group-containing copolymer, (b) phosphoric acid and (c)
A surface treatment agent containing a phosphate of a metal such as copper, cobalt, iron, and manganese, that is, a chromium-free surface treatment composition has been proposed.

[0006] JP-A-11-50010 discloses that
(A) a resin having a polyhydroxyether segment and a copolymer segment of an unsaturated monomer, (b) phosphoric acid and (c) a phosphate of a metal such as calcium, cobalt, iron, manganese, or zinc. Surface treatment agent, that is,
Chromium-free surface treatment compositions have been proposed.

[0007] JP-A-11-106945 discloses that
(A) polyvalent metal ions such as manganese, cobalt and zinc;
There has been proposed a water-soluble surface treating agent in which (b) an acid such as fluoroacid, phosphoric acid, and acetic acid, (c) a silane coupling agent, and (d) a water-soluble polymer having 2 to 50 polymerized units are dissolved in an aqueous medium. I have.

In the above methods (1) and (2), when a metal plate is coated with a sufficient amount of a surface treating agent, that is, when a film having a sufficient film thickness is applied, a reasonable corrosion resistance can be obtained. When a coating such that a part of a metal plate such as a convex portion was exposed was provided, or when the film thickness was too thin, the corrosion resistance was extremely insufficient. In other words, the metal plate had corrosion resistance only when the coverage of the surface treatment agent was 100%, but when the coverage was less than 100%, the corrosion resistance was insufficient. Conversely, when this is entirely coated thick, there is a problem that the appearance after press molding becomes white.

Further, the above prior arts each contain a phosphate, but when the phosphoric acid compound remains as a solid in the dried film, the color tone, particularly glossiness and whiteness, of the steel sheet surface is remarkably high. It has the problem of changing.

In recent years, particularly in office machines such as personal computers and copiers, home electric appliances such as air conditioners, automobile parts, and interior building materials, steel sheets having a blackened surface are widely used. A black steel sheet may be manufactured by applying a black paint on the surface of a zinc-based plated steel sheet, or by blackening the plated surface of a Zn-Ni plated steel sheet. However, the former is not conductive, and if the coating film is damaged during press molding, it is inferior in corrosion resistance, and in the latter case, there is no gloss until blackening treatment, and it is inferior in corrosion resistance, so after chromate treatment, It was necessary to apply a clear coating or a resin / chromate mixed paint.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and does not require a special wastewater treatment in the step of coating a surface treatment agent and the use of the obtained surface treatment metal material. Surface treatment of metal materials, especially zinc-coated steel sheets, improves defects, has excellent corrosion resistance, has little change in color after application, does not reduce gloss, and has excellent scratch resistance and fingerprint resistance Metal material having a coating,
In particular, it is an object of the present invention to provide a metal surface treatment composition that can be used as a zinc-based plated steel sheet.

[0012]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, even if the surface of a metal material typified by a galvanized steel sheet is coated very thinly, the corrosion resistance is impaired. Aqueous surface treatment composition containing no chromium-containing metal ions, water-soluble organic resin, water-dispersible organic resin and acid, which can form a film with little color tone change and no reduction in gloss, The present invention has been completed.

That is, the present invention provides (a) a metal ion,
(B) a water-soluble organic resin, (c) a water-dispersible organic resin,
In a metal surface treatment composition comprising (d) an acid and (e) an aqueous medium, (c) / [(a) + (b) + (c) +
(D)] is 50 to 98% by weight.

The preferred present invention is a metal surface treatment composition characterized in that the (a) metal ion is Al ion, Mg ion or Mn ion.

In a preferred aspect of the present invention, the water-soluble organic resin (b) is a polymer of a carboxyl group-containing monomer and / or a copolymer of a carboxyl group-containing monomer and another polymerizable monomer. A metal surface treatment composition comprising at least one polymer.

Further, the present invention is preferably a metal surface treatment composition, wherein the acid (d) is at least one selected from the group consisting of phosphoric acid, acetic acid, nitric acid and hydrofluoric acid.

Further, the present invention is a metal surface treatment composition characterized in that the metal surface treatment composition contains a polyhydric phenol carboxylic acid.

Further, the present invention preferably provides, in addition to the above three kinds of metal ions, Zn, Co, T
i, Sn, Ni, Fe, Zr, Sr, Y, Nb, Cu,
A metal surface treatment composition comprising ions of at least one metal selected from the group consisting of Ca, V and Ba.

The present invention is also a metal surface treatment composition characterized by further comprising an organic acid capable of coordinating to a divalent or higher-valent metal, in addition to the above four kinds of acids.

Further, the present invention is a metal surface treatment composition characterized in that the metal surface treatment composition further contains a coupling agent.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The chromium-free metal surface treatment composition of the present invention will be described in detail below. The metal ion of the present invention, a water-soluble organic resin, an aqueous metal surface treatment composition containing a water-dispersible organic resin and an acid, for example,
When applied to galvanized steel sheet, it has corrosion resistance on the plating layer, no change in color tone and luster on the steel sheet surface, and it is dense and chemically stable, and has scratch resistance and fingerprint resistance. Is formed.

Such a film is formed by mixing a metal ion and an acid with a water-soluble organic resin and a water-dispersible organic resin, and the metal ion reacts with the water-soluble organic resin and the metal material base layer. It is a thing. A water-dispersible organic resin layer and a clear film containing a water-soluble organic resin are present on the steel sheet surface, and function to improve corrosion resistance, prevent color change, and prevent low gloss. The coating is formed for the first time by applying the metal surface treatment composition of the present invention, and is different from a conventional zinc-based plated steel sheet coated with an organic resin.

The water-soluble organic resin contained in the metal surface treatment composition of the present invention is a polymer of a carboxyl group-containing monomer, or a copolymer of a carboxyl group-containing monomer and another polymerizable monomer. Preferably, at least one member selected from the group consisting of That is, it is at least one kind of polymer, at least one kind of copolymer, and a mixture of at least one kind of polymer and at least one kind of copolymer.

The carboxyl group-containing monomer includes, for example, ethylenically unsaturated carboxylic acids and derivatives thereof. The ethylenically unsaturated carboxylic acid is, for example, a monocarboxylic acid such as acrylic acid, methacrylic acid, crotonic acid and the like, and a dicarboxylic acid such as itaconic acid, maleic acid and fumaric acid. Derivatives include alkali metal salts, ammonium salts, organic amine salts and the like. Preferred are derivatives of acrylic acid and methacrylic acid.

The monomers copolymerized with the carboxyl group-containing polymer include hydroxyl group-containing monomers, various acrylates, methacrylates, aromatic vinyl compounds,
Examples thereof include vinyl ester compounds and other vinyl compounds, and sulfonic acid group-containing vinyl compounds and phosphoric acid group-containing vinyl compounds can also be used. Suitable monomers include styrene, butyl methacrylate, methacrylates such as methyl methacrylate, and the like.

In addition, a compound obtained by copolymerizing or adding a carboxyl group-containing monomer to a (meth) acrylate (co) polymer, an epoxy resin, an ester-modified epoxy resin, a urethane-modified epoxy resin, or the like is blended. Can be. Further, it is preferable to blend a polyhydric phenol carboxylic acid in addition to the water-soluble organic resin. Thereby, the corrosion resistance can be further improved. As the polyhydric phenol carboxylic acid, tannic acid, gallic acid and the like are suitable, and it is preferable to mix them at a ratio of 0.1 to 20% by weight of the solid content of the metal surface treatment composition. Furthermore, various additives for resins can be blended as long as the object of the present invention is not impaired.

In the case of a copolymer of a carboxyl group-containing monomer and another polymerizable monomer, the content of the carboxyl group-containing monomer should be 0.5% by weight or more of the total copolymer. preferable. When the content of the carboxyl group-containing monomer is 0.5% by weight or more, the denseness of the film is increased, so that the corrosion resistance is improved. The weight average molecular weight of the copolymer is not particularly limited, but is about 10,000 to several hundred thousand.

The metal ions contained in the metal surface treatment composition of the present invention react with the water-soluble organic resin and the metal material underlayer to form a film having excellent corrosion resistance. Metal ions are Al, Mg, Mn, Zn, Co, Ti, Sn, N
It is at least one metal ion selected from the group consisting of i, Fe, Zr, Sr, Y, Nb, Cu, Ca, V and Ba, but metal ions of Al, Mg and Mn are particularly preferred. The three types of metal ions are preferable because a pseudo-crosslinking reaction can be caused in a wide pH range at the time of forming a film, and a dense film can be obtained. This is because the anti-fingerprint property and the like are obtained, and the corrosion resistance is remarkably improved as compared with the case where the three kinds are not included as metal ions. In particular, this effect is further enhanced by combination with a carboxyl group-containing organic resin.

The metal ions are supplied by dissolving a salt such as a phosphate, a nitrate, a carbonate, a sulfate, an acetate, a hydrofluoride, or an oxide, a hydroxide, or a metal. Preferred are solutions of phosphates, nitrates, carbonates, sulfates, acetates and hydroxides of Al, Mg and Mn. The acid constituting these metal salts can also be a source of the acid (d), which is one of the components of the metal surface treatment composition of the present invention.

Al, Mg and Mn as metal ions
At least one metal ion selected from the group consisting of Zn, Co, Ti, Sn, Ni, Fe, Zr, S
At least one metal ion selected from the group consisting of r, Y, Nb, Cu, Ca, V and Ba is converted to an inorganic salt such as phosphoric acid, nitric acid, carbonic acid, sulfuric acid, an organic salt such as acetic acid, or a hydroxide. It is particularly preferable to use them together in a dissolved state. More preferred are aqueous solutions of Zn phosphate, acetate and the like.

The content of each metal ion in the solid content of the metal surface treatment composition is 0.1 to 5% by weight, preferably 0.1 to 5% by weight.
1 to 2% by weight. If it is less than 0.1% by weight, the corrosion resistance tends to be poor, and if it exceeds 5% by weight, the weldability tends to deteriorate. The above A in the solid content of the metal surface treatment composition
It is preferable that the total content of the three metal ions of 1, Mg and Mn is adjusted to 0.3 to 10% by weight.

The acid contained in the metal surface treatment composition of the present invention etches the surface of the galvanized steel sheet and further improves the adhesion of the film formed by the surface treatment composition to the galvanized steel sheet. In addition to preventing the peeling of the film and increasing the corrosion resistance, the pH of the metal surface treatment composition is set to 1.
It acts to adjust to 0 to 3.0. The acid is preferably at least one selected from phosphoric acid, acetic acid, nitric acid and hydrofluoric acid. The acid may be supplied as a metal salt as described above.

As the acid, an organic acid capable of coordinating to a divalent or higher valent metal is also used. In particular, when at least one of the organic acids is further blended with the above four exemplified acids, the corrosion resistance is further improved. The organic acid promotes etching of the plating surface and coordinates with metal ions to make the film more dense. Examples of the organic acid include oxalacetic acid, tricarballylic acid, citric acid, isocitric acid, succinic acid, malic acid, glutaric acid and the like. The content of the organic acid is not particularly limited, but is preferably 1 to 10% by weight based on the solid content of the metal surface treatment composition. If the amount is less than 1% by weight, the effect is not sufficient, the number of uncrosslinked points increases, and there is a possibility that the densification of the film may be hindered. Conversely, if it exceeds 10% by weight, the stability as a metal surface treatment composition cannot be maintained.

The content of the acid in the solid content of the metal surface treatment composition is not particularly limited, but is 1 to 20% by weight, preferably 5 to 15% by weight. If it is less than 1% by weight, p
Since H cannot be adjusted to the above range, the etching of zinc plating becomes insufficient and the corrosion resistance decreases. Conversely, if it exceeds 20% by weight, the dissolution of the zinc plating is too fast, and the plated surface tends to have uneven appearance.

Since the metal surface treatment composition of the present invention contains a predetermined amount of a water-dispersible organic resin, it is possible to prevent a change in color tone and a decrease in gloss of the steel sheet surface after coating. The water-dispersible organic resin includes a polymer or copolymer of a known unsaturated monomer other than a carboxyl group and a hydroxyl group-containing monomer, or a copolymer of the unsaturated monomer and the carboxyl group-containing monomer. Coalescing is preferably used. Suitable monomers include alkyl esters of methacrylic acid such as styrene, butyl methacrylate, and methyl methacrylate.

As the water-dispersible organic resin, those which can be stably and uniformly dispersed in an acidic aqueous solution (pH 1 to 3) can be used. For example, those used for the surface treatment of conventional metallic materials of polyester type, acrylic type and urethane type can be mentioned. These may be used in combination of two or more.

The water-dispersible organic resin preferably has a particle size of 1 μm or less. When the particle size exceeds 1 μm, the water-dispersible organic resin is dried, and even after the film is formed, unevenness remains on the surface of the film, and the glossiness is reduced. The glass transition temperature (Tg) of the water-dispersible organic resin is preferably from 20 to 100C. When the Tg is less than 20 ° C., the blocking resistance is poor even after the film is dried, and the Tg is 100%.
If the temperature exceeds ℃, the coating does not follow the deformation of the steel sheet during processing, and the coating is destroyed, and the corrosion resistance after processing is deteriorated.

The mixing ratio of the water-dispersible organic resin in the metal surface treating agent composition [(c) water-dispersible organic resin /
{Solid weight ratio represented by (a) metal ion + (b) water-soluble organic resin + (c) water-dispersible organic resin + (d) acid]
Should be 50-98% by weight. If the mixing ratio of the water-dispersible organic resin is less than 50% by weight, the color tone changes due to the application of the metal surface treating agent composition, and conversely, 9%.
If it exceeds 8% by weight, the corrosion resistance decreases. The mixing ratio is 6
0-95% by weight, preferably 75-95% by weight
Is particularly preferred.

When the metal surface treating composition of the present invention contains a coupling agent, the fingerprint resistance of the steel sheet surface can be improved. The coupling agent is preferably a coupling agent having at least one reactive functional group selected from an active hydrogen-containing amino group, an epoxy group, a vinyl group, a mercapto group and a methacryloxy group.
Particularly preferred are a silane coupling agent, a titanium coupling agent, and a zirconium coupling agent, and at least one selected from these. The content of the coupling agent is sufficient as long as it is substantially the same as the amount added to the surface treatment agent (composition) and the paint when the surface treatment is conventionally performed on the metal material.

As the silane coupling agent, for example, γ
-Aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β-aminoethyl-γ-
Aminopropyltrimethoxysilane, N-β-aminoethyl-γ-aminopropylmethyldimethoxysilane, γ
-Glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, β-3,4-epoxycyclohexylethyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltris (2-methoxyethoxy) silane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane , Vinyltriacetoxysilane, N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like.

Examples of the titanium coupling agent include di-isopropoxybis (acetylacetonatotitanium, dihydroxybis (lactato) titanium, diisopropoxy-bis- (2,4-pentadionate) titanium, isopropyltri (dioctyl) (Phosphate) titanate and the like.

Examples of the zirconium coupling agent include acetylacetone zirconium butyrate, zirconium lactate, zirconium acetate and the like.

In order to increase the denseness of the film of the metal surface treatment composition, the composition may contain a metal oxide. Metal oxides include silica (SiO ₂ ), MgO, Zr
O ₂ , Al ₂ O ₃ , SnO ₂ , Sb ₂ O ₃ , Fe ₂ O ₃
And at least one selected from the group consisting of Fe ₃ O ₄
Is a seed. A sufficient effect can also be exerted by using a metal oxide in the same amount as that of a surface treatment agent (composition) and a coating material which have been conventionally used for surface treatment of a metal material.

The metal surface treatment composition of the present invention is used after being dissolved or dispersed in an aqueous medium. The solution or dispersion is adjusted to have a solid concentration of 5 to 40% by weight, preferably 10 to 30% by weight. The aqueous medium is a mixed medium with water or an organic solvent or an inorganic solvent miscible with water. As the organic solvent, butyl cellosolve is exemplified. The mixing ratio is not particularly limited.

The metal surface treatment composition of the present invention can be applied to metal materials in general, but when applied to galvanized steel sheets, a remarkable effect can be exhibited. Galvanized steel sheets are electro-galvanized steel sheets, electro-galvanized nickel-plated steel sheets, hot-dip galvanized steel sheets, zinc-aluminum (Zn-
Al) Hot-dip coated steel sheet and the like are not particularly limited as long as they are zinc-plated steel sheets.

The metal surface treatment composition of the present invention is, for example,
To apply the composition to a galvanized steel sheet and form a film on the steel sheet, apply the composition to the surface of a galvanized steel sheet, press with a ringer roll, and dry to form a film. -The method of curing is common. To apply the composition to a metal material, a method such as roll coating, spray coating, brush coating, dip coating, curtain flow, or the like is used.

The thickness of the coating is preferably from 0.1 to 3.0 μm, more preferably from 0.5 to 1.5 μm. If the thickness is less than 0.1 μm, the coating cannot completely cover the plating layer, and the corrosion resistance deteriorates. Conversely, if the thickness exceeds 3.0 μm, there is a problem that the appearance after press molding is whitened and a coating film crack occurs in a bent portion.

[0048]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on embodiments. [Examples 1-33, 35-38: Comparative Examples 34, 39] The following metal materials AI were replaced by the following water-soluble organic resins AE, polyhydric phenolcarboxylic acids FG, metal ions (patterns AE). F), acids A to D, organic acids A to C, water-dispersible organic resins A to D, coupling agents A to C, and an aqueous medium
The surface treating agent composition obtained by mixing at the ratios shown in the table was roll-coated, and the metal material temperature was 170 in 15 seconds.
The film was heated and dried and cured at a temperature of ℃ to form a film having a predetermined thickness, thereby preparing a test piece.

Metal materials A to I: Sheet A: Electrogalvanized steel sheet (sheet thickness: 1.0 mm, Z
n: 20 g / m ² ) Sheet B: Electric zinc-nickel plated steel sheet (sheet thickness: 1.0
mm, Zn-Ni: 20 g / m ² , Ni: 12% by weight) Plate C: Electrolytic zinc-nickel plated anodized steel plate (blackened steel plate, thickness: 1.0 mm, Zn-Ni: 10)
g / m ² , Ni: 12% by weight) Sheet D: hot-dip galvanized steel sheet (sheet thickness: 1.0 mm, Z
n: 60 g / m ² ) Sheet E: alloyed hot-dip galvanized steel sheet (sheet thickness: 1.0 m)
m, Zn: 60 g / m ² , Fe: 10 wt%) Plate F: zinc-aluminum steel plate (“Galphan”, plate thickness: 1.0 mm, 60 g / m ² , Al: 5 wt%) Plate G: zinc- Aluminum steel sheet ("Galvalume",
Sheet thickness: 1.0 mm, 60 g / m ² , Al: 55% by weight) Sheet H: Cold rolled steel sheet (sheet thickness: 0.7 mm) Sheet I: aluminum sheet (sheet thickness: 1.0 mm)

Water-soluble organic resins A to E: The numerical values of the resins A to E are the weight ratio of the polymerized units of the copolymer. Resin A: acrylic acid / maleic acid = 90/10 (molecular weight 20,000) Resin B: acrylic acid / itaconic acid = 70/30 (molecular weight 15,000) Resin C: methacrylic acid / itaconic acid = 60/40
(Molecular weight 25,000) Resin D: butyl methacrylate / acrylic acid / 2HB
A = 20/40/40 (molecular weight: 30,000) 2HBA is 2-hydroxybutyl acrylate. Resin E: styrene / butyl methacrylate / acrylic acid = 40/30/30 (molecular weight: 30,000)

Polyhydric phenol carboxylic acids FG: resin F: water-soluble organic resin A / tannic acid = 95/5 resin G: water-soluble organic resin A / gallic acid = 90/10

Metal ions A to F: Numerical values of patterns are weight ratios of metal ions. Pattern A: Al ³⁺ / Mn ²⁺ / Mg ²⁺ / Men ⁺ = 1 /
1/1/0 Pattern B: Al ³⁺ / Mn ²⁺ / Mg ²⁺ / Men ⁺ = 1 /
1/1/1 (Me ^{n +} = Zn ²⁺ ) Pattern C: Al ³⁺ / Mn ²⁺ / Mg ²⁺ / Men ⁺ = 1 /
1/2 (Me ^{n +} = Ca ²⁺ ) Pattern D: Al ³⁺ / Mn ²⁺ / Mg ²⁺ / Me ₁ ^{n +} / M
e ₂ ^{n +} = ^2/1/1/2/1 (Me ₁ ^{n +} = Cu ²⁺ , Me
₂ ⁿ + = Sr ²⁺⁾ Pattern ^{E: Al 3+ / Mn 2+ /} Mg 2+ / Me n + = 1 /
0/0/0 Pattern F: Al ³⁺ / Mn ²⁺ / Mg ²⁺ / Men ⁺ = 2 /
1/0/0

Acids A to D: Acid A: phosphoric acid Acid B: acetic acid C: nitric acid D: hydrofluoric acid

Organic acids A to C: Organic acids A: Tricarballylic acid Organic acids B: Citric acid Organic acids C: Succinic acid

Water-dispersible organic resins AB: Emulsion A: Acrylic emulsion (solid content 40)
Emulsion B: Polyester emulsion (solid content 40% by weight) Emulsion C: Urethane-epoxy emulsion (solid content 40% by weight)

Silane coupling agents A to C: Silane A: γ-glycidoxypropyltrimethoxysilane (“KBM403”: manufactured by Shin-Etsu Chemical Co., Ltd.) Silane B: γ-glycidoxypropyltrimethoxysilane (“KBM402” : Shin-Etsu Chemical Co., Ltd.) Silane C: γ-glycidoxypropyltrimethoxysilane ("KBM603": Shin-Etsu Chemical Co., Ltd.)

The following characteristics (corrosion resistance of flat area, change in color tone, gloss value, blocking property, paint stability,
(Bending resistance and scratch resistance) were evaluated according to the following test methods. <Flat plate corrosion resistance> After shearing a test piece to a size of 50 mm x 100 mm, the end face was sealed, and a salt spray test (JIS)
Z-2371), and the area ratio of white rust after 48 hours was evaluated according to the following evaluation criteria. The results are shown in Table 2. ◎: 5% or less ○: More than 5% 10% or less △: More than 10% 20% or less ×: More than 20%

<Change in Color Tone> The change in color tone (L *) (ΔL *) before and after applying the surface treatment agent composition to the surface of the steel sheet was measured using a spectral color difference meter (“SQ2000”: manufactured by Nippon Denshoku Co., Ltd.). And evaluated according to the following evaluation criteria. The results are shown in Table 2. ◎: ΔL * is less than 5 Δ: ΔL * is 5 or more and less than 10 ×: ΔL * is 10 or more

<Gloss Value> The gloss (G value) after the surface treatment agent composition was applied to the steel sheet surface was measured using a spectral colorimeter (“SQ200”).
0 ": manufactured by Nippon Denshoku Co., Ltd.) and evaluated according to the following evaluation criteria. The results are shown in Table 2.: no gloss reduction less than 1 or gloss value increase △: gloss reduction of 1 or more Less than 5 ×: Gloss reduction of 5 or more

<Blocking property> Two test pieces superposed with the coating surfaces inside were 2.94 × 10 ⁵ N ·
While tightened with a torque of m, the sample was immersed in a thermostat at 40 ° C. for 6 hours. The test piece was peeled off, and the anti-blocking property was evaluated on a three-point scale according to the state of adhesion at the time of peeling. The results are shown in Table 2. ◎: No sticking (peeled off by the weight of the test piece) △: Slightly sticky (not peeled off by the weight of the test piece, but easily peelable) ×: Sticky (difficult to peel)

<Stability of treatment composition> After the surface treatment composition was left at 40 ° C. for 24 hours, the temperature of the composition was set to room temperature, and a test piece was prepared by the above-described method. In the same manner as described above, the change in color tone after aging was evaluated. The results are shown in Table 2. ◎: No color change (ΔL * is 0) Δ: Slight color change (ΔL * is 2 or less) ×: Color change (ΔL * exceeds 2)

<Scratch resistance> Test piece (20 mm × 200
mm), a load of 9.8 MPa and a sliding speed of 20 mm
A sliding test was performed under the conditions of a sliding temperature of 25 ° C./sec and a stereoscopic microscope (magnification: 10 ×). The results are shown in Table 2. ：: No damage (scratch area less than 5% in width direction) △: More damage (scratch area in width direction 5% or more 20)
%) ×: Many scratches (20% or more of scratches in the width direction)

<Fingerprint Resistance> The change in color tone (L value, a value, b value) before and after application of petrolatum to the test piece was measured using a spectral colorimeter (“SQ2000”: manufactured by Nippon Denshoku Co., Ltd.). ,
It was evaluated by ΔE represented by the following equation. The results are shown in Table 2. ◎: ΔE is 1 or less ○: ΔE is more than 1 2 or less Δ: ΔE is more than 2 3 or less ×: ΔE is more than 3

[0064]

(Equation 1)

<Bending Resistance> A test piece was 100 mm × 20 m.
After shearing to m, OT bending was performed, the bent portion was observed with a stereoscopic microscope (magnification: 20 times), and the presence or absence of cracks in the film was evaluated. The results are shown in Table 2. ◎: No cracks △: Some cracks (crack area 20% in width direction)
×): Large crack occurrence (crack area 20% or more in width direction)

[0066]

[Table 1]

[0067]

[Table 2]

[0068]

[Table 3]

[0069]

[Table 4]

[0070]

[Table 5]

[0071]

[Table 6]

[0072]

The metal surface treatment composition of the present invention is a so-called non-polluting non-chromate treatment agent which does not contain chromium, has excellent paint stability, and is typified by zinc-coated steel sheet surface-treated with this. The material is particularly excellent in corrosion resistance, color tone change, gloss reduction prevention, scratch resistance, fingerprint resistance, blocking property, and bending resistance.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigeru Umino 1-term Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba F-term in Technical Research Institute, Kawasaki Steel Co., Ltd. 4D075 CA02 CA33 DA06 DB02 DB05 EA06 EB01 EC45 4K026 AA02 AA07 AA09 AA12 AA13 AA22 BA01 BA03 BB01 BB08 BB10 CA16 CA18 CA26 CA28 CA32 CA37 CA38 CA39

Claims (8)

[Claims] 1. A metal surface treatment composition comprising (a) a metal ion, (b) a water-soluble organic resin, (c) a water-dispersible organic resin, (d) an acid and (e) an aqueous medium, wherein (c) /
A metal surface treatment composition wherein [(a) + (b) + (c) + (d)] is 50 to 98% by weight. 2. The method according to claim 2, wherein (a) the metal ion is Al ion, Mg
The metal surface treatment composition according to claim 1, which is an ion or a Mn ion. (3) The water-soluble organic resin (b) is a copolymer of at least one carboxyl group-containing monomer polymer and / or a carboxyl group-containing monomer and another polymerizable monomer. The metal surface treatment composition according to claim 1, wherein the composition is at least one of the following. 4. The metal according to claim 1, wherein the acid (d) is at least one selected from the group consisting of phosphoric acid, acetic acid, nitric acid and hydrofluoric acid. Surface treatment composition. 5. The metal surface treatment composition according to claim 3, wherein the metal surface treatment composition contains a polyhydric phenol carboxylic acid. 6. In addition to the three kinds of metal ions, Zn, Co, Ti, Sn, Ni, Fe, Z
The metal surface according to any one of claims 2 to 5, comprising at least one metal ion selected from the group consisting of r, Sr, Y, Nb, Cu, Ca, V and Ba. Treatment composition. 7. The metal surface according to claim 4, further comprising an organic acid capable of coordinating to a divalent or higher valent metal, in addition to said four kinds of acids. Treatment composition. 8. The metal surface treatment composition according to claim 1, wherein said metal surface treatment composition further comprises a coupling agent.