KR20040012513A - Metallic surface-treating composition, metallic surface-treating method and galvanized steel sheet - Google Patents

Abstract

PURPOSE: A chemical conversion treatment agent and a chemical conversion treatment method by which a galvanized steel sheet can satisfactorily be subjected to chemical conversion treatment without requiring a load on treatment for a used solution, and a galvanized steel sheet which is obtained by the chemical conversion method, and has excellent rust preventability and excellent adhesion are provided. CONSTITUTION: The metal surface treatment composition comprises niobium oxide colloidal particles, wherein the metal surface treatment composition further comprises water dispersible silica, wherein the metal surface treatment composition further comprises at least one kind of compound selected from the group consisting of vanadium compounds, zirconium compounds and titanium compounds, wherein the metal surface treatment composition further comprises a water base resin, and wherein the metal surface treatment composition contains 10 to 30 wt.% of solid content. The metal surface treatment method is characterized in that a galvanized steel sheet is surface-treated with the metal surface treatment composition to form a film. The coated galvanized steel sheet is characterized in that it is obtained by the metal surface treatment method.

Description

METALLIC SURFACE-TREATING COMPOSITION, METALLIC SURFACE-TREATING METHOD AND GALVANIZED STEEL SHEET}

The present invention relates to a metal surface treatment composition, a metal surface treatment method and a galvanized steel sheet.

As a steel material excellent in corrosion resistance, the galvanized steel plate which performed zinc plating, zinc alloy plating, etc. is used. Such a galvanized steel sheet is oxidized when the zinc plated layer is in contact with air, and white rust is generated. For this reason, it is necessary to apply a surface treatment to prevent oxidation. In addition, depending on the application, the galvanized steel sheet may be used without being coated. In such a case, it is important to have anti-rust (rust prevention) capability in an unpainted state.

As such treatment, a chromate treatment using a chromium compound is known. When the chromate treatment is performed, white rust is prevented and a fairly good galvanized steel sheet can be obtained. However, waste liquid containing a chromium compound can be disposed of for disposal. Since enormous burden is required, the method of carrying out the chemical process by the non-chromate process which does not use chromium is examined.

Japanese Patent Laid-Open Nos. 9-241856, 2001-172771 and 2001-247977 disclose metal surface treatment agents for galvanized steel sheets containing metal salt compounds. However, surface treatment by such a treatment agent is performed. The galvanized steel sheet did not have sufficient properties such as rust resistance and coating adhesion.

Japanese Patent Laid-Open No. 2002-105659 discloses a chemical treatment solution for galvanized steel sheet containing oxyacid salts, manganese compounds, titanium compounds and phosphoric acid or phosphates of metals selected from molybdenum, vanadium, tungsten, niobium and tantalum. However, manganese compounds should be used as the chemical treatment liquid for galvanized steel. Since manganese compounds also require a huge burden for the disposal of the waste liquid, it is preferable not to use them.

In addition, water-dispersible silica is used as an anti-corrosive component used in the metal surface treatment composition. However, when water-dispersible silica is used alone, anti-corrosion property is not sufficient, and the galvanized steel sheet cannot provide anti-rust capability. In addition, it was impossible to obtain sufficient rust resistance.

In view of the present state as described above, the present invention does not have to be burdened with the treatment of the waste liquid, and a chemical treatment agent and a chemical treatment method capable of satisfactory chemical treatment of a galvanized steel sheet and also obtained by such a chemical method. An object of the present invention is to provide a galvanized steel sheet excellent in rust resistance and adhesion.

The present invention is a metal surface treatment composition comprising niobium oxide colloidal particles.

It is preferable that the said metal surface treatment composition further contains water dispersible silica. Moreover, it is preferable that it contains at least 1 sort (s) of compound chosen from the group which consists of a vanadium compound, a zirconium compound, and a titanium compound.

It is preferable that the said metal surface treatment composition also contains an aqueous resin.

This invention relates to the metal surface treatment method characterized by surface-treating a galvanized steel plate with the above-mentioned metal surface treatment product, and forming a film.

The invention also relates to a coated galvanized steel sheet obtained by the above metal surface treatment method.

In the following, the present invention is described in more detail.

The metal surface treatment composition of the present invention is obtained by dispersing niobium oxide colloidal particles in an aqueous medium. The niobium oxide colloidal particles having a smaller particle diameter form a more stable and denser niobium oxide treated film, and therefore It is more preferable because it can provide stability and antirust property. Moreover, it does not need to contain the component which burdens the disposal of waste liquids, such as chromium and a manganese.

The niobium oxide colloidal particles used in the present invention are those in which niobium oxide is dispersed in water in a particulate state. For example, niobium oxide is not strictly formed, and amorphous in the intermediate state of niobium hydroxide and niobium oxide. ) May be in a state.

The metal surface treatment composition of this invention can be prepared by using niobium oxide sol manufactured by the well-known method. The said niobium oxide sol is not specifically limited, For example, Unexamined-Japanese-Patent No. 6-321543, Unexamined-Japanese-Patent 8-. And those produced by known methods described in Japanese Patent Application Laid-Open No. 143314 and Japanese Patent Application Laid-Open No. Hei 8-325018. The niobium oxide sol commercially available from Taki Chemical Co., Ltd. can be used.

In the known method for producing niobium oxide sol, for example, niobium oxide is dissolved in hydrofluoric acid, added to ammonia water, filtered and washed to obtain a slurry of niobium hydroxide, followed by addition of hydroxide dihydrate and subsequent addition of water. The reaction is carried out under reflux conditions under stirring to obtain a uniform niobium oxide colloidal particle solution. The end of the reaction, that is, whether or not a uniform niobium oxide colloidal particle solution can be obtained or not is obtained. It can be judged by the color, and it can be judged as a uniform state if it is blue.

The metal surface treatment composition of this invention can be prepared by diluting the said niobium oxide sol to the required concentration or mixing other components as needed.

It is preferable that the niobium oxide colloidal particles contained in the metal surface treatment composition of the present invention have an average particle diameter of 1000 nm or less. The particle size is more preferably 2 to 600 nm, and more preferably 2 to 100 nm. The smaller the average particle diameter described above is, the more stable and dense niobium oxide treated film is formed, thus making it stable and rustproof to the object. It is more preferable because it can provide. Here, particle size measurement was performed by the particle size distribution measuring apparatus (NICOMP model-370 type by Pacific Scientific) by the dynamic scattering method.

In the metal surface treatment composition of the present invention, when the niobium oxide colloidal particles convert Nb in the colloidal particles into Nb ₂ O ₅ , the content rate of the metal surface treatment composition with respect to the total solid content is preferably 1% by mass or more. If it is less than 1 mass%, since sufficient rust prevention property cannot be obtained, it is not preferable. Further, if the value is converted to Nb in the niobium oxide colloidal particles as Nb ₂ O ₅ content of the entire solids content of the metal surface treatment composition, and the content by percentage is more preferably 2 to 30% by weight.

In order to improve the rust resistance of the surface treatment film, the metal surface treatment composition of the present invention preferably further contains water dispersible silica. The water dispersible silica can not be sufficiently rust preventive when used alone, but is used in combination with the niobium oxide colloid particles. By improving the rust prevention ability.

The water-dispersible silica is not particularly limited, and examples thereof include spherical silica, chain silica, aluminum modified silica, and the like having few impurities such as sodium.

Although the said spherical silica is not specifically limited, For example, colloidal silica, such as "Snotex N", "Snotex O", "Snotex OXS", "Snotex UP" (all are the Nissan Chemical Co., Ltd. product), or Fumed silica, such as "Aerosol" (made by Nippon Aerosol Co., Ltd.), etc. are mentioned. Although it does not specifically limit as said chain silica, For example, "Snotex PS-M" and "Snotex PS- Silica gel, such as M0 "(all made by Nissan Chemical Co., Ltd.), etc. The commercially available silica gel, such as" Athelite AT-20A "(made by Asahi Telephone Co., Ltd.), etc. are mentioned as said aluminum modified silica. Can be.

When the surface treatment composition used in the metal surface treatment method of the present invention contains the water-dispersible silica, the SiO ₂ content in the surface treatment composition is preferably 80% by mass or less based on the total solids of the surface treatment composition. If it exceeds, there is a problem that the coating becomes soft and the rust resistance is lowered. The upper limit is more preferably 60% by mass and even more preferably 30% by mass.

When the metal surface treatment composition of the present invention containing the water-dispersible silica Nb ₂ O ₅ / SiO ₂ ratio of the total solids of the surface treatment composition is preferably in the range of 1 / 99~99 / 1 .Nb ₂ If the content of O ₅ is less than 1/99, the anti-corrosion property by Nb ₂ O ₅ is not sufficiently exhibited. The ratio is more preferably 2/98 to 30/70.

The metal surface treatment composition of the present invention preferably further contains at least one compound selected from the group consisting of a vanadium compound, a zirconium compound and a titanium compound in order to improve the rust resistance of the surface treatment film. The vanadium compound, the zirconium compound and the titanium By using at least one compound selected from the group consisting of the compound together with niobium oxide colloidal particles, it is possible to further improve the rust resistance. It is more preferable to use together three to four or five components of at least one compound selected from the group consisting of niobium colloid particles, the water dispersible silica and the vanadium compound, zirconium compound and titanium compound.

The vanadium compound is not particularly limited, and examples thereof include a vanadil compound, a vanadium pentoxide, a vanadate salt, a plastic condensate of vanadate, a heterocondensate of vanadate and a mixture thereof. Vanadium (II) compounds such as vanadium (II) oxide and vanadium (II) hydroxide; Vanadium (III) compounds such as vanadium (III) oxide (V ₂ O ₃ ); Vanadium (IV) compounds such as vanadium (IV) oxide (V ₂ O ₄ ) and vanadium halide (VOX ₂ ); Vanadium (V) compounds such as vanadium oxide (V) (V ₂ O ₅ ); Vanadate salts such as various ortho vanadate salts, meta vanadate salts or pyro vanadate salts, and halogenated vanadil (VOX ₃ ); Or mixtures thereof. The vanadate is not particularly limited, and examples thereof include ammonium salts, alkali metal salts, alkali earth metal salts (for example, magnesium and calcium) and metal salts of other typical elements (for example, For example, aluminum, tin, etc., and transition metal salts (for example, manganese, cobalt, iron, nickel), etc. can be mentioned. Among them, alkaline earth metal salts, zinc salts, manganese salts, and cobalt salts are preferable. These may be obtained by calcining oxides of vanadium, oxides of various metals, hydroxides, carbonates and the like at 600 ° C or higher.

Examples of the zirconium compound is not particularly limited, for example, zirconium hydrofluoric acid (H ₂ ZrF _6); Salts of zirconic hydrofluoric acid such as ammonium, lithium, sodium, potassium of zirconic hydrofluoric acid; ammonium zirconate oxycarbonate ((NH ₄ ) ₂ ZrO (CO ₃ ) ₂ ); Zirconium salt compounds such as zirconium hydroxide, zirconium carbonate, zirconium borate, zirconium hydroxide, zirconium sulfate, zirconium nitrate, zirconyl nitrate, and zirconium fluoride; Organic zirconium compounds such as dibutyl zirconium dilauryl, dibutyl zirconium dioctate, zirconium naphthenate, zirconium octylate and acetylacetone zirconium; Or such a mixture.

The titanium compound is not particularly limited and includes, for example, titanium hydrofluoric acid, titanium ammonium fluoride, titanium titanium fluoride, titanium titanium fluoride, fluoro titanic acid and alkali metal fluoro titanate; Fluorine-titanium compounds such as titanium fluoride; Potassium titanium hydroxide, titanium isopropoxide, isopropyl titanate, titanium ethoxide, titanium 2-ethyl 1-hexanolite, tetraisopropyl titanate, tetra n-butyl titanate, butyl titanate dimer, titanium laurate, titanium triethanol Titanium organic compounds such as laminate; Or mixtures thereof.

When the metal surface treatment composition of the present invention comprises at least one compound selected from the group consisting of the vanadium compound, the zirconium compound and the titanium compound, the compound is added to the total solids of the surface treatment composition in terms of V, Zr and Ti metals. It is preferable that it is 30 mass% or less. It is not preferable to exceed 30 mass% because the additive effect is saturated and uneconomical. In addition, the vanadium compound, zirconium compound, and titanium compound have a surface in terms of V, Zr, and Ti metal. It is preferable that it is 0.5 mass% or more with respect to the total solid of a processing composition. Since the said vanadium compound, a zirconium compound, and a titanium compound are less than 0.5 mass%, antirust property may fall, and the said lower limit is 1 mass%. It is more preferable and it is still more preferable that it is 2.5 mass%. The value is more preferably 15% by mass and even more preferably 7.5% by mass.

Furthermore, the metal surface treatment composition of the present invention preferably contains an aqueous resin. The aqueous resin is not particularly limited, but for example, an acrylic resin, a polyolefin resin, a polyurethane resin, an epoxy clock resin, and an ethylene acrylic acid copolymer. Resins, phenolic resins, polyester resins, alkyd resins, melamine resins, polycarbonate resins, polyacrylic acids and other thermal crosslinkable and thermoplastic resins.

These aqueous resins may be used singly or in combination of two or more thereof, or may be used in combination. In addition, when the aqueous resins are used, the film forming properties are improved, and a leveling agent and a wetting agent are used to form a more uniform and smooth coating film. Enhancers and antifoams may also be used.

When the metal surface treatment composition of this invention contains the said aqueous resin, it is preferable that aqueous resin is 90 mass% or less with respect to the total solid of a surface treatment composition. When it exceeds 90 mass%, an addition effect is saturated and it is uneconomical. Moreover, it is preferable that the said aqueous resin is 5 mass% or more with respect to a total solid. It is not preferable because the rust prevention property may fall when the said aqueous resin is less than 5 mass%. The said lower limit is 10 mass It is more preferable that it is% and it is still more preferable that it is 20 mass%. It is more preferable that the said upper limit is 80 mass%, and it is still more preferable that it is 70 mass%.

It is preferable that the metal surface treatment composition of this invention contains a phosphate compound. The phosphoric acid compound contained in the metal surface treatment composition of this invention elutes the metal which is a to-be-processed material, and forms a metal phosphate salt on the surface of a to-be-processed material, and surface-treats. The rust resistance of the membrane can be further improved.

The phosphoric acid compound is not particularly limited as long as it is a compound capable of forming phosphate ions in water, and examples thereof include: phosphoric acid; phosphates such as Na ₃ PO ₄ , Na ₂ HPO _4, and NaH ₂ PO ₄ ; Condensed phosphoric acid or salts thereof such as condensed phosphoric acid, polyphosphoric acid, metaphosphoric acid, pyrophosphoric acid and ultraphosphoric acid.

When the metal surface treatment composition of this invention contains the said phosphate compound, it is preferable that the phosphoric acid compound content rate in a surface treatment composition exists in the range of the lower limit 0.1 mass% and the upper limit 20 mass% with respect to the total solid of a surface treatment composition. If the content is less than 0.1% by mass, the effect of improving the corrosion resistance may not be sufficient. If the content is more than 20% by mass, excessive etching may be caused on the galvanized steel sheet or gelation of the composition containing the aqueous resin may occur. It is not preferable. It is 0.5 mass% more preferable at the said lower limit, and 10 mass% is more preferable than the said upper limit.

It is preferable that the metal surface treatment composition of this invention also contains a silane coupling agent. By containing a silane coupling agent, adhesiveness with respect to the metal surface of a film can be improved, and it acts as a crosslinking agent of aqueous resin, and corrosion resistance is improved. The silane coupling agent is not particularly limited, and examples thereof include vinyl methoxysilane, vinyl trimethoxysilane, vinyl ethoxysilane, vinyl triethoxysilane, 3-amino propyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, N- (1,3-dimethylbutylidene) -3- (trie Methoxysilyl) -1-propanamine, N, N'-bis [3- (trimethoxysilyl) propyl] ethylene diamine, N- (β-amino ethyl) -γ-aminopropylmethyl dimethoxysilane, N- ( β-aminoethyl) -γ-aminopropyl Trimethoxysilane, γ-aminopropyl trimethoxysilane, γ-aminopropyl triethoxysilane, γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane, γ-glycidoxy Propylmethyl dimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, γ-methacryloxypropyl triethoxysilane, γ-mercaptopropyl Trimethoxysilane, γ-mercaptopropyl triethoxysilane, N- [2- (vinyl benzyl amino) ethyl] -3-aminopropyl trimethoxysilane, and the like.

Among them, particularly preferred silane coupling agents include vinyl methoxysilane, vinyl ethoxysilane, 3-aminopropyl triethoxysilane, 3-glycidoxypropyl trimethoxysilane, 3-methacryloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, N, N'-bis [3- (trimethoxy Silyl) propyl] ethylene diamine and the like. The said silane coupling agent may be used individually by 1 type, or may be used in combination of 2 or more types.

When the surface treatment composition of this invention contains the said silane coupling agent, it is preferable to contain the silane coupling agent in surface treatment composition within the range of 0.5 mass% of lower limits and 30 mass% of upper limits with respect to the total solid of a surface treatment composition. When the content of the silane coupling agent is less than 0.5% by mass, the effect of improving the corrosion resistance and adhesion with the chromium-free rust-preventing coating agent may be insufficient. When the content of the silane coupling agent exceeds 30% by mass, the additive effect may be saturated and uneconomical. It is more preferable that the lower limit is 1 mass%, and it is more preferable that the upper limit is 20 mass%.

The surface treatment composition of this invention is a value in the range of 3 mass% of lower limits and 50 mass% of upper limits as solid content mass. If the solid content is less than 3%, it is not preferable because a sufficient film thickness for maintaining the rust preventive ability cannot be obtained when the surface treatment composition is applied, and if the content exceeds 50 mass%, gelation of the composition may occur. As for a lower limit, 10 mass% is more preferable, and it is more preferable that the said upper limit is 30 mass%.

Since the metal surface treatment composition of this invention which consists of said each component is excellent also in stability, it can stably surface-treat a galvanized steel plate.

The method for producing the metal surface treatment composition of the present invention is not particularly limited, but for example, at least one compound selected from the group consisting of niobium oxide colloid particles, water dispersible silica, vanadium compounds, zirconium compounds, and titanium compounds, an aqueous resin It can be put in a container in order, and can be obtained by stirring to make it uniform.

The metal surface treatment method of this invention is a method of processing a galvanized steel plate with the said metal surface treatment composition. The galvanized steel plate which can be processed by the metal surface treatment method of this invention is not specifically limited, For example, zinc Zinc-based electroplating such as galvanized steel sheet, zinc-nickel plated steel sheet, zinc-iron plated steel sheet, zinc-chromium-plated steel sheet, zinc-aluminum-plated steel sheet, zinc-titanium plated steel sheet, zinc-magnesium-plated steel sheet, zinc-manganese-plated steel sheet And zinc or zinc-based alloy-coated steel sheets such as hot dip galvanized and deposited galvanized steel sheets.

The said metal surface treatment method performs the process by the said metal surface treatment composition to the said galvanized steel plate degreased as needed. The method of performing the process of the said metal surface treatment composition is not specifically limited, For example, generally Roll coats, shower coats, air sprays, airless sprays, curtain flow coats, brush coating, and dipping methods.

It is preferable to heat-dry after heat-processing with the said metal surface treatment composition. The said drying temperature is the range of the minimum of 50 degreeC, and the upper limit of 250 degreeC is preferable. If it is less than 50 degreeC, evaporation rate of moisture will be slow and drying efficiency will deteriorate. There is a case. When it exceeds 250 degreeC, the component in the film formed at high temperature may decompose. It is more preferable that the said lower limit is 60 degreeC, and it is more preferable that the said upper limit is 150 degreeC. Moreover, the drying time is a lower limit of 1 second, An upper limit of 300 seconds is preferable, and a lower limit of 3 seconds and an upper limit of 60 seconds are more preferable.

The metal surface treatment composition of the present invention it is preferred that the application amount, when converted to a solid content mass of the coating, applied in a range of lower limit value O.lg / m ^2, the upper limit 10.0g / m ^2. The coating amount 0.lg / m ² If it is less than the thickness, the workability may be degraded or the rust resistance may not be sufficiently obtained. If the coating amount exceeds 10.0 g / m ² , it is economically disadvantageous or the thickness is increased because there is no improvement effect due to the increase of the film thickness. Therefore, the rolling may be difficult. The lower limit is more preferably 0.2 g / m ² , and more preferably 0.3 g / m ^2. The upper limit is more preferably 5.0 g / m ² and 3.0 g / m ^2. Is more preferable.

The present invention also relates to a galvanized steel sheet obtained by the above metal surface treatment method. The galvanized steel sheet of the present invention is excellent in rust prevention ability because a good surface treatment coating film is formed, and white blue or the like does not occur.

The metal surface treatment composition of the present invention is a chemical treatment agent containing niobium oxide colloidal particles, thereby providing good anti-corrosiveness and adhesiveness equivalent to chromate treatment for galvanized steel sheet by a component that does not require a burden upon the treatment of waste liquid.

Thus, the metal surface treatment method which can perform favorable metal surface treatment with respect to a galvanized steel plate is provided. In addition, the galvanized steel sheet excellent in rust prevention property and adhesiveness can be provided by the metal surface treatment method of this invention.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited only to these Examples.

Examples 1 to 8 and Comparative Examples 1 to 3

Niobium oxide colloidal particles, water dispersible silica, vanadium compound and zirconium compound are added to a container with stirring in this order, and water is added to prepare a solid content concentration within the range of 10 to 15%, and the surface treatment composition as shown in Table 1 below. Got.

Examples 9-21, Comparative Examples 4 and 5

Niobium oxide colloidal particles, water-dispersible silica, vanadium compound, zirconium compound, titanium compound, aqueous resin, phosphate compound and silane coupling agent were added to the container with stirring in this order, water was added to prepare a solid content concentration of 15%. The surface treatment composition as described in 2 was obtained.

Comparative Example 6

A commercially available coated chromate treatment agent (manufactured by Nippon Paint Co., Ltd .; subcoat S-100) was applied so that the chromium adhesion amount was 20 mg / m ² .

Spraying at 60 ° C. for 2 minutes using a sub cleaner 53S (manufactured by Nippon Paint Co., Ltd.), an alkali degreasing agent, commercially available commercially available galvanized steel sheet (manufactured by Nippon Test Panel Co., Ltd .; 70 mm × 150 mm × 0.4 mm) After drying, washing with water and coating the metal surface treatment agent used in Examples 1 to 21 and Comparative Examples 1 to 5 with a bar coater so as to have a dry adhesion amount of 0.2 to 1.0 g / m ² , a metal surface temperature of 80 Drying at 占 폚 gave a test plate. In addition, the coating type chromate treatment agent used in Comparative Example 6 was coated with a bar coater so as to have a chromium adhesion amount of 20 mg / m ² , and then dried at a metal surface temperature of 80 ° C. to obtain a test plate. The obtained test plate was evaluated in the following manner. The results are shown in Tables 1 and 2 below.

The niobium oxide colloidal particles, water dispersible silica, vanadium compound, zirconium compound, titanium compound, aqueous resin, phosphoric acid compound, and silane coupling agents used in Tables 1 and 2 below are as follows.

[Niobium Oxide Colloidal Particles]

A; Niobium oxide sol (Nb ₂ O ₅ ; 10%, particle diameter; 5 nm, manufactured by Taki Chemical Co., Ltd.)

B; Niobium Oxide Colloidal Particle Water Dispersion (Nb ₂ O ₅ ; 10%, Particle Size; 2000nm)

[Water Dispersible Silica]

A; Snowtex O (SiO ₂ ; 20%, manufactured by Nissan Chemical Co., Ltd.)

B; Aderite AT-20A (SiO ₂ ; 20%, manufactured by Asahi Teletech Co., Ltd.)

C; Snowtex N (SiO ₂ ; 20%, manufactured by Nissan Chemical Industries, Ltd.)

[Vanadium compound]

A; Ammonium metavanadate (V; 43.6%, reagent)

B; Vanadium pentaoxide (V; 56.0%, reagent)

C; Vanadil Sulfate (Vanadil Sulfate ， V; 22.6% ， Emerging Chemical Industry Co., Ltd.)

Zirconium Compounds

A; Zircozol-7 (zirconium ammonium carbonate, Zr; 74.0%; Daiichi rare element industry company make)

B; Zirconium (IV) acetylacetonite (Zr; 18.7%, Reagent)

C; Zirconyl Nitrate Dihydrate (Zr; 33.0%, Reagent)

Titanium Compound

A; Organics TC-400 (Titanium Triethanol Aluminate; Ti; 10.4%, manufactured by Matsumoto Pharmaceutical Co., Ltd.)

[Aqueous resin]

A; PC 2200 (Ethylene Acrylic Acid Copolymer Resin, Solid Content Concentration; 30%, manufactured by Shoei Chemical Co., Ltd.)

B; Sparkle 420 (Polyurethane resin, solid content concentration: 32%, Daiichi Pharmaceutical Co., Ltd.)

C; Dulimer-AC-10L (polyacrylic acid, solid content concentration: 40%, product of Nippon Pure Chemical Co., Ltd.)

[Phosphate compound]

A; Diammonium hydrogen phosphate (solid concentration; 100%, reagent)

[Silane coupling agent]

A; Cyraes S-510 (γ-glycidoxypropyl trimethoxysilane, solid content concentration; 100%, manufactured by Thixo Corporation)

B; Cyraes S-210 (vinyl methoxy silane, solid content concentration; 100%, manufactured by Thixo Corporation)

(Assessment Methods)

Corrosion Resistance

The surface of the test plate and the cross-section and the back of the processed part extruded by 8 mm with a Ericsson Tester are tape-sealed, and 5% saline is sprayed onto the painted surface of the test plate at a temperature of 35 ° C., and then white or blue is generated after 24 or 72 hours. The area ratio was evaluated according to the following evaluation criteria.

◎: No white rust

O: White rust is less than 10%

?: The same area as above is 10% or more but less than 30%:

(Triangle | delta): The same area as the above is 30% or more and less than 50%

X: The same area as above is 50% or more

Table 1

* 1: mass as Nb ₂ O ₅

* 2: mass as SiO ₂

TABLE 2

* 1: mass as Nb ₂ O ₅

* 2: mass as SiO ₂

As is clear from the results of Tables 1 and 2, the metal surface treatment composition of the present invention containing niobium oxide colloidal particles is excellent in rust resistance and can suppress the occurrence of white rust. Further, in addition to the niobium oxide colloidal particles, water dispersibility When using a silica, an aqueous resin, a vanadium compound, etc., a metal surface treatment composition improves antirust ability by such a component. On the other hand, the metal surface treatment composition which does not contain niobium oxide colloid particle has a chemical film which is excellent in antirust property. It is not possible to obtain a good galvanized steel sheet because it cannot be provided. Furthermore, the metal treatment composition of the present invention also has excellent anti-rusting ability after processing.

Since the metal surface treatment composition of the present invention is made of the above niobium oxide colloidal particles, it is excellent in rust prevention and adhesiveness and can suppress the occurrence of white blue. The composition of the present invention is a chromium compound widely used in the art. Since it does not contain manganese compounds, a huge burden for treating these waste liquids is also unnecessary.

Claims (7)

A metal surface treatment composition comprising niobium oxide colloidal particles. The method of claim 1, A metal surface treatment composition further comprising water dispersible silica. The method according to claim 1 or 2, A metal surface treatment composition further comprising at least one compound selected from the group consisting of a vanadium compound, a zirconium compound, and a titanium compound. The method according to claim 1, 2 or 3, A metal surface treatment composition, further comprising an aqueous resin. The metal surface treatment method which surface-treats a galvanized steel plate with a metal surface treatment composition as described in any one of Claims 1-4, and forms a film. A coated galvanized steel sheet obtained by the method for treating metal surfaces according to claim 5. The method of claim 1, Metal surface treatment composition, characterized in that the content of the total solids contained in the composition is in the range of 10% to 30% by mass.