JP2014101562A - Composition for spray-coating surface treatment, method for producing surface treated galvanized steel sheet, and surface treated galvanized steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environmentally-adapted type composition for spray-coating surface treatment containing no hexavalent chromium that may provide a sufficient corrosion resistance and excellent appearance (finishing state) of a film on forming a surface treatment film on a surface of a galvanized steel sheet which is a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet by applying using a spray coating process.SOLUTION: The composition for spray-coating surface treatment according to the present invention comprises specified quantities of: a particular titanium-containing aqueous liquid (A); a nickel compound (B); a fluorine-containing compound (C); an organic phosphorous compound (D); a vanadate compound (E); an ether-based organic solvent having 4 to 6 carbon atoms (F) containing no resin component and zirconium carbonate compound, which is used by applying at least on side of galvanized steel sheet which is a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet to form a surface treatment film.

Description

  The present invention relates to a spray-coated surface treatment composition, a method for producing a surface-treated galvanized steel sheet, and a surface-treated galvanized steel sheet. In particular, the present invention is an environmentally-applicable surface treatment composition that does not contain hexavalent chromium, and is suitable for being applied to the surface of a galvanized steel sheet that is a galvanized steel sheet or an alloyed galvanized steel sheet by a spray coating method. About.

  For the purpose of improving corrosion resistance (white rust resistance, red rust resistance) on the surface of hot-dip galvanized steel sheets or alloyed hot-dip galvanized steel sheets, steel plates for home appliances, building steels, and automobiles are conventionally used. Steel plates that have been subjected to chromate treatment with a treatment liquid mainly composed of dichromic acid or salts thereof are widely used. This chromate treatment is often performed by a spray coating method in a production line of a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet, and is economical. The spray coating method is a relatively simple method in which a chromate treatment solution is applied by spraying or is poured by a shower. Thereafter, the amount of coating (liquid film) is adjusted with a roll or an air squeezer and dried in an oven or the like.

  However, the chromate treatment uses hexavalent chromium, which is a pollution-controlling substance, and because of the environmental considerations and the waste liquid treatment of the chromate treatment liquid requires a great deal of labor and expense, the treatment liquid does not contain chromium. Chromate-free technology is being studied.

Here, when a treatment liquid not containing hexavalent chromium is applied to a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet, the coating amount after drying is 1 g / m in order to develop corrosion resistance equivalent to or better than chromate. ^Although about ^{2 is} required, it is difficult to obtain such a coating amount by the spray coating method. That is, in the spray coating method in which the liquid film is strongly squeezed with a roll or air after spraying, it is difficult to obtain a coating amount necessary for developing corrosion resistance. For this reason, in this case, it has been common to apply a treatment liquid to the surface of the steel sheet using a roll coating method and dry it to form a surface treatment film. This is because the roll coating method makes it relatively easy to adjust the coating amount by adjusting the rotational speed of the applicator roll and the pressing pressure between the rolls.

  Patent Document 1 discloses a surface treatment composition in which a specific titanium-containing aqueous liquid, a nickel compound or / and a cobalt compound, and a fluorine-containing compound are blended in a predetermined ratio as a treatment liquid that does not contain hexavalent chromium. Using this, it is applied to a molten Zn-Al alloy-plated steel sheet by a roll coating method and dried to form a surface treatment film, thereby having excellent corrosion resistance and blackening resistance, and excellent plating appearance. A technique for obtaining a chromium-free surface-treated molten Zn-Al alloy-plated steel sheet is described.

JP 2008-291350 A

  The roll coating method is suitable for accurately controlling the film thickness immediately after coating to several microns, but requires large-scale equipment such as a two-stage or three-stage backup roll, and requires capital investment. It becomes. Therefore, the inventors of the present invention used a spray coating method that is a conventional facility and that can be applied with a simpler facility, and applied the same composition as that of Patent Document 1 to the surface of the galvanized steel sheet and the galvannealed steel sheet. Each surface was coated and dried to form a surface treatment film, and an attempt was made to obtain the same characteristics as in Patent Document 1. However, when a surface treatment film was formed by spray coating for various compositions similar to Patent Document 1, foaming was observed in the liquid film immediately after coating when a part of the composition was coated, and then the film was dried. There was a problem that the appearance (finished state) of the formed surface treatment film was greatly impaired. Moreover, even when any of the above various compositions is applied, there is a problem that the spray coating method does not provide sufficient corrosion resistance to the steel sheet.

  Therefore, in view of the above problems, the object of the present invention is to provide sufficient corrosion resistance and good coating appearance even when a surface-treated coating is formed by spray coating on the surface of a hot dip galvanized steel plate or an alloyed hot dip galvanized steel plate. The present invention provides an environmentally-applicable surface treatment composition that does not contain hexavalent chromium and can exhibit a (finished state), surface-treated galvanized steel sheet or alloyed galvanized steel using this composition It is providing the manufacturing method of the surface treatment galvanization steel plate which is a steel plate, and providing the surface treatment galvanization steel plate obtained by this method.

  As a result of further investigation by the present inventors to achieve this object, the composition described in Patent Document 1 containing a resin component is applied to the surface of a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by spray coating. In all cases, it was found that foaming was observed in the liquid film immediately after application. This is presumably because the resin component having a hydrophilic part and a hydrophobic part in the molecule is oriented at the liquid-gas interface, and the interfacial tension is lowered to stabilize the foam.

  In addition, the reason why the present inventors cannot obtain sufficient corrosion resistance when a surface treatment film is formed on a hot dip galvanizing by a spray coating method is that after spraying by a spray coating method, it is squeezed by a ringer or the like. In the meantime, the inventor came up with the idea that a thicker liquid film is formed compared to the roll coating method. That is, in the spray coating method, a thick liquid film is formed. Therefore, when a highly reactive treatment liquid such as the composition described in Patent Document 1 is used, etching on the surface of the hot dip galvanized steel sheet proceeds excessively. Many cracks that reach the base material are formed, and sufficient corrosion resistance cannot be ensured.

  Moreover, when the composition of patent document 1 was apply | coated to the galvannealed steel plate, it turned out that an external appearance is hard to be obtained especially and corrosion resistance is hard to express. This is because the surface of the alloyed hot-dip galvanized steel sheet is less reactive than the hot-dip galvanized steel sheet, and many irregularities are formed on the surface due to alloying. This is thought to be because thinning occurs in the concave portions, and many cracks are formed in the thick film portions of the concave portions so as to reach the base material. Therefore, as a result of reviewing the components of the composition, it was newly found that the cracks generated in the hot dip galvanized steel sheet and the alloyed hot dip galvanized steel sheet are caused by the zirconium carbonate compound in the composition. In addition, in order to reduce the excess etching on the surface of the hot dip galvanized steel sheet while ensuring the reactivity on the surface of the galvannealed steel sheet, it is necessary to set the ratio of the fluorine-containing compound and the ratio of the organophosphate compound within a specific range. Newly found that there is.

  As a result, a specific titanium-containing aqueous liquid, nickel compound, fluorine-containing compound, organophosphate compound, vanadic acid compound, and a specific ether system are formed on the surface of a galvanized steel sheet that is a galvanized steel sheet or an alloyed galvanized steel sheet. Using an organic solvent, in particular a fluorine-containing compound ratio and an organophosphate compound ratio in a certain range, and using a composition that does not contain a resin component and a zirconium carbonate compound, it can be manufactured with simple equipment such as a spray coating method and has excellent corrosion resistance. And it discovered that the galvanized steel plate which has a film | membrane external appearance (finished state) was obtained, and came to complete this invention.

This invention is made | formed based on such knowledge, The summary structure is as follows.
(1) Mixing at least one titanium compound selected from hydrolyzable titanium compounds, low-condensates of hydrolyzable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide with hydrogen peroxide water The obtained titanium-containing aqueous liquid (A) is 10 to 45% by mass in terms of solid content, the nickel compound (B) is 0.01 to 1% by mass in terms of solid content, and the fluorine-containing compound (C) is solid. 10 to 20% by mass, 40 to 60% by mass of the organic phosphoric acid compound (D) and 0.1 to 30% by mass of the vanadic acid compound (E) in terms of the solid content. And 5 to 30 parts by mass of the ether-based organic solvent (F) having 4 to 6 carbon atoms with respect to the total of 100 parts by mass of (A), (B), (C), (D) and (E). Containing,
A composition containing no resin component and zirconium carbonate compound,
A composition for spray coating surface treatment, which is used for forming a surface treatment film by applying at least one surface of a galvanized steel plate which is a hot dip galvanized steel plate or an alloyed hot dip galvanized steel plate by a spray coating method.

  (2) The composition for surface treatment by spray application according to the above (1), wherein the fluorine-containing compound (C) is at least one selected from zircon ammonium fluoride and zircon hydrofluoric acid.

  (3) The spray coating surface treatment composition described in (1) or (2) above is applied to at least one surface of a galvanized steel sheet which is a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet by a spray coating method. A method for producing a surface-treated galvanized steel sheet, characterized in that a surface-treated film is formed by squeezing the coating amount with a ringer roll or air and drying.

  (4) A surface-treated galvanized steel sheet produced by the production method described in (3) above.

  According to the present invention, since the resin component is not contained in the surface treatment composition, it is difficult to foam when applied to the surface of a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet by a spray coating method, and then dried. The appearance (finished state) of the surface-treated film thus obtained is not impaired. Further, by adding an ether-based organic solvent having 4 to 6 carbon atoms, it is possible to prevent repelling on the surface of the galvannealed steel sheet, which also contributes to a good appearance of the surface-treated film. Furthermore, since no zirconium carbonate compound is contained, the occurrence of film cracks in the recesses on the galvannealed steel sheet can be suppressed, and as a result, sufficient corrosion resistance can be obtained. Moreover, the reactivity with the steel plate surface in the case of using a spray coating method becomes an appropriate composition by setting the fluorine-containing compound that greatly affects the reactivity to a solid content ratio of 10 to 20% by mass. Even a surface-treated film formed by coating with can provide sufficient corrosion resistance. Moreover, the reactivity with an alloyed hot-dip galvanized steel plate surface becomes a suitable composition by making an organic phosphoric acid compound into 40-60 mass% in the ratio of solid content, and especially outstanding corrosion resistance can be expressed. In this way, sufficient corrosion resistance and good coating appearance (finished state) can be exhibited when a surface-treated film is formed by spray coating on the surface of a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet. It was possible to provide an environmentally applicable surface treatment composition that does not contain any hexavalent chromium.

  Hereinafter, the present invention will be described in more detail.

(Hot-dip galvanized steel sheet and galvannealed steel sheet)
The hot dip galvanized steel sheet and the alloyed hot dip galvanized steel sheet to which the surface treatment composition of the present invention is applied are steel sheets that have been subjected to hot dip galvanization and galvannealed hot dip galvanization as defined in JIS G 3302: 2010, respectively. The steel sheet subjected to hot dip galvanizing and alloying hot dip galvanizing (hot dip galvanized steel sheet and galvannealed steel sheet, respectively) has the thickness of the oxide layer and the etching property according to the present invention. The surface-treated hot-dip galvanized steel sheet and the surface-treated galvannealed steel sheet on which the surface-treated film is formed by spray-coating the surface-treating composition of the present invention have excellent corrosion resistance. The steel type of the base steel plate is not particularly limited, and various steel plates such as low carbon steel, extremely low carbon steel, IF steel, and high tensile steel plates to which various alloy elements are added can be used.

  In order to prevent film defects and unevenness when the surface treatment film is formed on the surface of the plating film, alkali degreasing, solvent degreasing, surface adjustment treatment (alkaline surface adjustment treatment or Treatment such as acidic surface conditioning treatment can be performed.

  In addition, for the purpose of preventing blackening in the usage environment (a kind of oxidation phenomenon on the plating surface), an iron group metal ion (one or more kinds of Ni ion, Co ion, Fe ion) is previously applied to the plating surface as necessary. Surface conditioning treatment with an acidic or alkaline aqueous solution containing can also be performed.

(Method for forming surface treatment film)
In the present invention, the method of applying the surface treatment composition to the surface of the hot dip galvanized steel sheet or alloyed hot dip galvanized steel sheet is a spray coating method. Here, the “spray coating method” in the present specification means a method of spraying the surface treatment composition (treatment liquid) on the steel plate surface or a method of pouring it with a shower. Thereafter, the coating amount is squeezed with a ringer roll or air and dried to form a film on the surface of the steel sheet. Detailed conditions for coating will be described later.

(Composition for spray coating surface treatment)
In the composition for spray coating surface treatment of the present invention, the specific titanium-containing aqueous liquid (A) is 10 to 45% by mass in terms of the solid content, and the nickel compound (B) is 0.01 to 1 in terms of the solid content. 10% to 20% by mass of the fluorine-containing compound (C) in a proportion of the solid content, 40 to 60% by mass of the organophosphate compound (D) in the proportion of the solid content, and the vanadic acid compound (E). 0.1 to 30% by mass in terms of the solid content, and the ether organic solvent (F) having 4 to 6 carbon atoms is a total of 100 of (A), (B), (C), (D) and (E) The composition contains 5 to 30 parts by mass with respect to parts by mass and does not contain a resin component and a zirconium carbonate compound, and this composition does not contain hexavalent chromium. By adopting such a composition, even if it is applied to the surface of a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet by a spray coating method, sufficient corrosion resistance and good film appearance (finished state) are exhibited. A surface-treated film can be obtained. This will be described in more detail below.

  The titanium-containing aqueous liquid (A) contains at least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low condensates, titanium hydroxide and titanium hydroxide low condensates. It is an aqueous liquid containing titanium obtained by mixing with hydrogen oxide water.

  The hydrolyzable titanium compound is a titanium compound having a hydrolyzable group directly bonded to titanium, and generates titanium hydroxide by reacting with water such as water or water vapor. The hydrolyzable titanium compound may be one in which all of the groups bonded to titanium are hydrolyzable groups, or a part of the groups bonded to titanium may be hydrolyzable groups. The hydrolyzable group is not particularly limited as long as it generates titanium hydroxide by reacting with moisture as described above. For example, a lower alkoxyl group or a group that forms a salt with titanium (for example, Halogen atoms such as chlorine, hydrogen atoms, sulfate ions, etc.).

As the hydrolyzable titanium compound containing a lower alkoxyl group as a hydrolyzable group, in particular, represented by the general formula Ti (OR) ₄ (wherein R represents the same or different alkyl group having 1 to 5 carbon atoms) Tetraalkoxy titanium is preferred. Examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, and a tert-butyl group. Can be mentioned. Typical examples of the hydrolyzable titanium compound having a group capable of forming a salt with titanium as a hydrolyzable group include titanium chloride and titanium sulfate.

  The low condensate of the hydrolyzable titanium compound is a low condensate of the above hydrolyzable titanium compounds. The low condensate may be one in which all of the groups bonded to titanium are hydrolyzable groups, or a part of the groups bonded to titanium may be hydrolyzable. For hydrolyzable titanium compounds whose hydrolyzable group forms a salt with titanium (for example, titanium chloride, titanium sulfate, etc.), an aqueous solution of the hydrolyzable titanium compound and an alkaline solution such as ammonia or caustic soda are used. Orthotitanic acid (titanium hydroxide gel) obtained by the reaction can also be used as a low condensate.

  As the low condensate of the hydrolyzable titanium compound and the low condensate of titanium hydroxide, a compound having a condensation degree of 2 to 30 can be used, and a compound having a condensation degree of 2 to 10 is particularly preferable. This is because if the degree of condensation is 30 or less, a stable titanium-containing aqueous liquid can be obtained without causing white precipitation when mixed with hydrogen peroxide.

  The hydrolyzable titanium compounds listed above, low-condensates of hydrolyzable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide can be used alone or in combination of two or more thereof. Tetraalkoxytitanium, which is a hydrolyzable titanium compound represented by the formula, is more preferred because precipitation hardly occurs when mixed with hydrogen peroxide.

  As the titanium-containing aqueous liquid (A), any conventionally known liquid can be used without particular limitation as long as it is an aqueous liquid containing titanium obtained by mixing the above-described titanium compound and hydrogen peroxide solution. . Specifically, the following can be mentioned.

  (I) A titanyl ion hydrogen peroxide complex or an aqueous solution of titanic acid (peroxotitanium hydrate) obtained by adding hydrogen peroxide to a hydrous titanium oxide gel or sol (JP-A 63-35419, JP 1-2224220 gazette).

  (Ii) A liquid for forming a titania film obtained by synthesizing a titanium hydroxide gel produced from an aqueous solution of titanium chloride or titanium sulfate and a basic solution with a hydrogen peroxide solution (Japanese Patent Laid-Open No. 9-71418, (See Kaihei 10-67516).

  When obtaining this titania film-forming liquid, titanium hydroxide gel called orthotitanic acid is precipitated by reacting an aqueous solution of titanium chloride or titanium sulfate having a salt-forming group with titanium and an alkaline solution such as ammonia or caustic soda. Let Next, the titanium hydroxide gel is separated by decantation with water, washed thoroughly with water, further added with hydrogen peroxide water, and excess hydrogen peroxide is decomposed and removed, whereby a yellow transparent viscous liquid can be obtained.

  The ortho-titanic acid thus precipitated is in a gel state polymerized by polymerization of OH or hydrogen bonds, and as such cannot be used as an aqueous liquid containing titanium. When hydrogen peroxide solution is added to this gel, a part of OH is in a peroxidized state, dissolved as a peroxotitanate ion or in a kind of sol state in which the polymer chain is divided into low molecules, and excess hydrogen peroxide Is decomposed into water and oxygen, and can be used as an aqueous liquid containing titanium for forming an inorganic film. Since this sol contains only oxygen and hydrogen atoms in addition to titanium atoms, when it is changed to titanium oxide by drying or firing, only water and oxygen are generated, so carbon components necessary for thermal decomposition such as sol-gel method and sulfate Further, it is not necessary to remove the halogen component, and a titanium oxide film having a relatively high density can be formed even at a low temperature.

  (Iii) Hydrogen peroxide is added to an aqueous solution of an inorganic titanium compound such as titanium chloride or titanium sulfate to form a peroxotitanium hydrate, and then the solution obtained by adding a basic substance is allowed to stand or be heated. A titanium oxide forming solution obtained by forming a precipitate of a titanium hydrate polymer, and then removing hydrogen and other dissolved components derived from at least a titanium-containing raw material solution (Japanese Patent Application Laid-Open 2000-247638, JP-A-2000-247639).

  The titanium-containing aqueous liquid (A) using a hydrolyzable titanium compound and / or a low condensate thereof (hereinafter simply referred to as “hydrolyzable titanium compound a”) as the titanium compound is obtained by converting hydrolyzable titanium compound a to hydrogen peroxide. It can be obtained by reacting with water at a reaction temperature of 1 to 70 ° C. for about 10 minutes to 20 hours. In the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a, the hydrolyzable titanium compound a is hydrolyzed with water by reacting the hydrolyzable titanium compound a with hydrogen peroxide. A product obtained by producing a hydroxyl group-containing titanium compound and then coordinating hydrogen peroxide to the hydroxyl group-containing titanium compound, and this hydrolysis reaction and coordination by hydrogen peroxide occur simultaneously. It produces a chelate solution that is extremely stable at room temperature and can withstand long-term storage. The titanium hydroxide gel used in the conventional production method is partially three-dimensional by Ti—O—Ti bond, and the titanium-containing aqueous liquid (A) obtained by reacting this gel with hydrogen peroxide solution is composition and stable. Sex is essentially different.

  Further, when the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a is heated or autoclaved at 80 ° C. or higher, a titanium oxide dispersion liquid containing ultrafine particles of crystallized titanium oxide is obtained. When the heat treatment or autoclave treatment is less than 80 ° C., crystallization of titanium oxide does not proceed sufficiently. The average particle diameter of the titanium oxide ultrafine particles contained in the titanium oxide dispersion thus produced is preferably 10 nm or less, more preferably about 1 to 6 nm. When the average particle diameter of the titanium oxide ultrafine particles is larger than 10 nm, the film forming property is deteriorated (when the film is dried after coating to form a film, cracking occurs at a film thickness of 1 μm or more), which is not preferable. The appearance of this titanium oxide dispersion is translucent. Such a titanium oxide dispersion can also be used as the titanium-containing aqueous liquid (A).

  By applying and drying the surface treatment composition (G) containing the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a on the surface of the plated steel sheet (for example, heat drying at a low temperature), A dense titanium oxide-containing film (surface treatment film) having excellent adhesion can be formed.

  The heating temperature after applying the surface treatment composition (G) is, for example, preferably 200 ° C. or less, particularly preferably 150 ° C. or less. ) Of titanium oxide-containing film can be formed. Moreover, when the titanium oxide dispersion obtained through the heat treatment or autoclave treatment as described above at 80 ° C. or more is used as the titanium-containing aqueous liquid (A), only the surface treatment composition (G) is applied. Since a crystalline titanium oxide-containing film can be formed, it is useful as a coating material for materials that cannot be heat-treated.

  Further, as the titanium-containing aqueous liquid (A), a titanium-containing aqueous liquid (A1) obtained by reacting the hydrolyzable titanium compound a with hydrogen peroxide in the presence of a titanium oxide sol can also be used. .

  The titanium oxide sol is a sol in which amorphous titania fine particles and / or anatase type titania fine particles are dispersed in water (for example, an aqueous organic solvent such as an alcohol or alcohol ether may be added if necessary). As this titanium oxide sol, conventionally known ones can be used. For example, (i) a titanium oxide aggregate obtained by hydrolyzing a titanium-containing solution such as titanium sulfate or titanyl sulfate, (ii) titanium alkoxide, etc. Titanium oxide aggregates obtained by hydrolyzing organic titanium compounds of (ii), (iii) Titanium oxide aggregates obtained by hydrolyzing or neutralizing titanium halide solutions such as titanium tetrachloride, etc. Amorphous titania sol dispersed in water or a sol in which the titanium oxide aggregate is fired to form anatase titanium fine particles and dispersed in water can be used.

  In the firing of the amorphous titania, the amorphous titania can be converted into anatase titania by firing at a temperature of at least the crystallization temperature of anatase, for example, a temperature of 400 ° C. to 500 ° C. or more. Examples of the aqueous sol of titanium oxide include, for example, TKS-201 (trade name, manufactured by TEIKA CORPORATION, anatase crystal form, average particle diameter 6 nm), TA-15 (trade name, manufactured by NISSAN CHEMICAL CO., LTD., Anatase crystal form). STS-11 (trade name, manufactured by Ishihara Sangyo Co., Ltd., anatase type crystal form) and the like.

  In the titanium-containing aqueous liquid (A1), the mass ratio x / y between the titanium oxide sol x and the titanium hydrogen peroxide reactant y (reaction product of the hydrolyzable titanium compound a and hydrogen peroxide solution) is 1 / A range of 99 to 99/1, preferably about 10/90 to 90/10 is suitable. If the mass ratio x / y is less than 1/99, the effect of adding the titanium oxide sol cannot be sufficiently obtained in terms of stability, photoreactivity, etc. Absent.

  The titanium-containing aqueous liquid (A1) can be obtained by reacting the hydrolyzable titanium compound a with hydrogen peroxide at a reaction temperature of 1 to 70 ° C. for about 10 minutes to 20 hours in the presence of a titanium oxide sol. The production form and characteristics of the titanium-containing aqueous liquid (A1) are the same as those of the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, but in particular, by using a titanium oxide sol. , It is possible to suppress a partial condensation reaction during the synthesis to increase the viscosity. The reason is considered to be that the condensation reaction product is adsorbed on the surface of the titanium oxide sol, and polymerization in a solution state is suppressed.

  Further, when the titanium-containing aqueous liquid (A1) is subjected to a heat treatment or autoclave treatment at 80 ° C. or higher, a titanium oxide dispersion containing ultrafine particles of crystallized titanium oxide is obtained. The titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above also describes the temperature conditions for obtaining this titanium oxide dispersion, the particle diameter of the crystallized titanium oxide ultrafine particles, the appearance of the dispersion, etc. It is the same. Such a titanium oxide dispersion can also be used as the titanium-containing aqueous liquid (A1).

  Similar to the titanium-containing aqueous liquid (A) using the hydrolyzable titanium compound a described above, the surface treatment composition (H) containing the titanium-containing aqueous liquid (A1) is applied to the surface of the plated steel sheet and dried ( For example, by performing heat drying at a low temperature, a dense titanium oxide-containing film (surface treatment film) having excellent adhesion can be formed.

  The heating temperature after applying the surface treatment composition (H) is satisfactory if it is dried. For example, the steel sheet temperature is preferably 200 ° C. or lower, particularly preferably 150 ° C. or lower. An anatase-type titanium oxide-containing film containing a small amount of can be formed.

  As described above, of the titanium-containing aqueous liquid (A), the titanium-containing aqueous liquid (A) and the titanium-containing aqueous liquid (A1) using the hydrolyzable titanium compound a are excellent in storage stability, corrosion resistance, and the like. It is particularly preferable to use these in the present invention.

  The compounding ratio of hydrogen peroxide water to at least one titanium compound selected from hydrolyzable titanium compounds, hydrolyzable titanium compound low condensates, titanium hydroxide, titanium hydroxide low condensates is titanium compounds It is preferable to set it as 0.1-100 mass parts in conversion of hydrogen peroxide with respect to 10 mass parts, and it is more preferable to set it as 1-20 mass parts. If the blending ratio is 0.1 parts by mass or more, chelate formation is sufficient and cloudy precipitation does not occur. On the other hand, if it is 100 parts by mass or less, unreacted hydrogen peroxide hardly remains and is stored. It is preferable because it is difficult to release dangerous active oxygen.

  The hydrogen peroxide concentration of the hydrogen peroxide solution is not particularly limited, but it is preferably about 3 to 30% by mass from the viewpoint of ease of handling and the solid content of the product liquid related to coating workability.

  Other sols and pigments can be added and dispersed in the titanium-containing aqueous liquid (A) as necessary. Examples of the additive include commercially available titanium oxide sol, titanium oxide powder, mica, talc, silica, barita, clay, and the like, and one or more of these can be added.

  In order to ensure the stability of the treatment liquid, the content of the titanium-containing aqueous liquid (A) in the surface treatment compositions (G) and (H) is 10% by mass to 45% by mass in terms of solid content. And

  The nickel compound (B) is blended for improving blackening resistance, and examples of the nickel compound (B) include inorganic nickel compounds such as nickel acetate, nickel nitrate, and nickel sulfate. 1 type (s) or 2 or more types can be used. Of these, nickel acetate is preferred from the viewpoint of improving blackening resistance. The compounding quantity of a nickel compound (B) is 0.01 mass%-1 mass% in the ratio of the solid content of a composition. If the content is 0.01% by mass or more, sufficient blackening resistance can be improved, while if the content is 1% by mass or less, the corrosion resistance is not deteriorated.

  The fluorine-containing compound (C) is blended to improve corrosion resistance. Examples of the fluorine-containing compound (C) include zircon ammonium fluoride, zircon potassium fluoride, zircon hydrofluoric acid, titanium fluoride. Inorganic fluorine-containing compounds such as ammonium fluoride, hydrofluoric acid, and ammonium hydrofluoride can be used, and one or more of these can be used. Of these, it is preferable from the viewpoint of corrosion resistance to use at least one selected from zircon ammonium fluoride and zircon hydrofluoric acid.

  The compounding quantity of a fluorine-containing compound (C) is 10 mass%-20 mass% in the ratio of the solid content of a composition. If it is 10 mass% or more, the reactivity at the time of a spray process can be obtained appropriately, and sufficient corrosion resistance can be obtained. On the other hand, if the content is 20% by mass or less, the reactivity does not become too high, and the etching amount on the plating surface can be suppressed to obtain sufficient corrosion resistance.

  Examples of the organic phosphate compound (D) include 1-hydroxymethane-1,1-diphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid, 1-hydroxypropane-1,1-diphosphonic acid, and the like. Suitable examples include hydroxyl group-containing organic phosphorous acid; carboxyl group-containing organic phosphorous acid such as 2-hydroxyphosphonoacetic acid, 2-phosphonobutane-1,2,4-tricarboxylic acid, and salts thereof. These 1 type (s) or 2 or more types can be used. The organic phosphoric acid compound (D) has an effect of improving the storage stability of the titanium-containing aqueous liquid (A). Among them, 1-hydroxyethane-1,1-diphosphonic acid has a particularly large effect. It is particularly preferred to use this.

  The compounding quantity of an organic phosphoric acid compound (D) is 40 mass%-60 mass% in the ratio of the solid content of a composition. If the compounding amount of the organic phosphate compound (D) is 40% by mass or more, sufficient storage stability can be obtained, and appropriate reactivity can be obtained with the galvannealed steel sheet. If it is 60 mass% or less, sufficient water resistance can be obtained.

  Examples of the vanadate compound (E) include lithium metavanadate, potassium metavanadate, sodium metavanadate, ammonium metavanadate, and anhydrous vanadate, and one or more of these can be used. In order to ensure sufficient corrosion resistance, the compounding amount of the vanadic acid compound (E) is 0.1% by mass to 30% by mass in terms of the solid content of the composition. Of these, ammonium metavanadate is preferable from the viewpoint of water adhesion resistance.

  Examples of the ether organic solvent (F) having 4 to 6 carbon atoms include glycol ether organics such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol isobutyl ether, and ethylene glycol tert-butyl ether. A solvent is mentioned, These 1 type (s) or 2 or more types can be used. If the carbon number is 4 or more, it is possible to obtain a finished state of a good film, and if the carbon number is 6 or less, it is excellent in compatibility in the processing agent, so that a processing agent having excellent stability can be obtained. it can.

  The blending amount of the ether-based organic solvent (F) having 4 to 6 carbon atoms is 5 to 30 parts by mass with respect to 100 parts by mass in total of (A), (B), (C), (D) and (E). It is. If this blending amount is 5 parts by mass or more, appearance defects due to repelling when coated on an alloyed hot-dip galvanized steel sheet can be prevented, while if it is 30 parts by mass or less, corrosion resistance may deteriorate. Absent. In particular, ethylene glycol monobutyl ether is preferably 5 to 25 parts by mass in terms of improving the finish of the film and not reducing the drying property of the film.

  One of the characteristics of the composition of the present invention is that it does not contain a resin component. By not including the resin component in the surface treatment composition, foaming hardly occurs when applied by a spray coating method, and the appearance (finished state) of the surface treatment film obtained by subsequent drying is not impaired.

  Another feature of the composition of the present invention is that it does not contain a zirconium carbonate compound. By not containing a zirconium carbonate compound in the surface treatment composition, cracks in the recesses can be suppressed and excellent corrosion resistance can be achieved even on plated surfaces with rugged surfaces such as galvannealed steel sheets. It becomes.

  In the composition of the present invention, if necessary, for example, etching agents such as silane coupling agents and inorganic phosphate compounds, heavy metal compounds other than the components defined by the present invention, thickeners, surfactants, dyes Etc. can be contained. Moreover, the composition of this invention can be diluted with hydrophilic solvents, such as methanol, ethanol, isopropyl alcohol, an ethylene glycol type solvent, a propylene glycol type solvent, for example as needed, and can be used.

(Surface-treated galvanized steel sheet and manufacturing method thereof)
The method for producing a surface-treated galvanized steel sheet according to the present invention comprises applying the composition described so far to at least one surface of a galvanized steel sheet which is a hot dip galvanized steel sheet or an alloyed hot dip galvanized steel sheet by a spray coating method. It can be obtained by forming the surface treatment film by squeezing the coating amount with a roll or air and drying it. As described above, the surface-treated galvanized steel sheet thus obtained does not contain hexavalent chromium in the film, and exhibits sufficient corrosion resistance and good film appearance (finished state).

Next, the conditions of the spray coating method suitable for the present invention will be described. In the spray coating method, there is no problem if the spray pressure is such that the entire surface of the steel sheet is in contact with the liquid, and it is preferably 0.2 kgf / cm ² or more. This is because if it is 0.2 kgf / cm ² or more, it is considered that an appearance defect due to insufficient liquid does not occur. After spraying, squeeze the liquid with a ringer roll or air. The squeezing pressure of the ringer roll or the air pressure may be adjusted within a range in which a target adhesion amount can be obtained.

The adhesion amount per one side of the surface treatment film formed according to the present invention is preferably 0.05 to 0.5 g / m ² . By long film coating weight of 0.05 g / m ² or more, the corrosion resistance can be obtained more reliably, if 0.5 g / m ² or less, because there is less possibility that corrosion resistance decreases cracked film is there.

  EXAMPLES Hereinafter, although this invention is demonstrated further in detail using an Example, this invention is not limited to a following example at all.

(Plated steel sheet)
As the base steel plate of the surface-treated steel plate, the plated steel plate shown in Table 1 was used. No. Reference numerals 2 and 3 are galvanized steel sheets used in the examples of the present invention, and the rest are galvanized steel sheets used in the comparative examples.

(Surface treatment composition)
Below, each component (A)-(F), (Y), (Z) used for the composition of this Example is shown.
[Production of titanium-containing aqueous solution (A)]
<Production Example 1 (Titanium-containing aqueous liquid T1)>
Ammonia water (1: 9) was added dropwise to a solution in which 5 cc of a titanium tetrachloride 60 mass% solution was made 500 cc with distilled water to precipitate titanium hydroxide. After washing with distilled water, 10 cc of a 30% by mass hydrogen peroxide solution was added and stirred to obtain a yellow translucent viscous titanium-containing aqueous liquid T1 containing titanium.
<Production Example 2 (Titanium-containing aqueous liquid T2)>
A mixture of 10 parts of tetraiso-propoxytitanium and 10 parts of iso-propanol was dropped into a mixture of 10 parts by weight of 30% by weight hydrogen peroxide and 100 parts by weight of deionized water with stirring at 20 ° C. over 1 hour. Thereafter, aging was carried out at 25 ° C. for 2 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid T2.
<Production Example 3 (Titanium-containing aqueous liquid T3)>
A titanium-containing aqueous liquid T3 was obtained under the same production conditions as in Production Example 2 except that tetra-n-butoxy titanium was used instead of tetraiso-propoxy titanium used in Production Example 2.
<Production Example 4 (Titanium-containing aqueous liquid T4)>
A titanium-containing aqueous liquid T4 was obtained under the same production conditions as in Production Example 2 except that tetramer of tetraiso-propoxytitanium used in Production Example 2 was used instead of tetraiso-propoxytitanium.
<Production Example 5 (Titanium-containing aqueous liquid T5)>
A titanium-containing aqueous liquid was produced under the same production conditions as in Production Example 2, except that hydrogen peroxide was used in 3 times the amount of Production Example 2, dropped at 50 ° C over 1 hour, and further aged at 60 ° C for 3 hours. T5 was obtained.
<Production Example 6 (Titanium-containing aqueous liquid T6)>
The titanium-containing aqueous liquid T3 produced in Production Example 3 was further heat-treated at 95 ° C. for 6 hours to obtain a white yellow translucent titanium-containing aqueous liquid T6.
<Production Example 7 (Titanium-containing aqueous liquid T7)>
A mixture of 10 parts by mass of tetraiso-propoxytitanium and 10 parts by mass of iso-propanol, 5 parts by mass (solid content) of “TKS-203” (trade name, manufactured by Teika Co., Ltd.), 30% by mass hydrogen peroxide solution The mixture was added dropwise to a mixture of 10 parts by mass and 100 parts by mass of deionized water with stirring at 10 ° C. over 1 hour. Thereafter, the mixture was aged at 10 ° C. for 24 hours to obtain a yellow transparent, slightly viscous titanium-containing aqueous liquid T7.

[Nickel compound (B)]
B1: Nickel acetate B2: Nickel nitrate B3: Nickel sulfate

[Fluorine-containing compound (C)]
C1: Zircon ammonium fluoride C2: Zircon hydrofluoric acid C3: Zircon sodium fluoride C4: Zircon potassium fluoride

[Organic Phosphate Compound (D)]
D1: 1-hydroxyethane-1,1-diphosphonic acid D2: 1-hydroxymethane-1,1-diphosphonic acid

[Vanadate compound (E)]
E1: Ammonium metavanadate E2: Sodium metavanadate

[Ether-based organic solvent (F)]
F1: Ethylene glycol monobutyl ether (C6)
F2: Propylene glycol monomethyl ether (4 carbon atoms)
F3: Diethylene glycol monoethyl ether (carbon number 6)
F4: Ethylene glycol monomethyl ether (3 carbon atoms)
F5: Propylene glycol monobutyl ether (carbon number 7)

[Zirconium carbonate compound (Y)]
Y1: Ammonium zirconium carbonate Y2: Sodium zirconium carbonate

[Resin component (Z)]
Z1: Superflex E-2500 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., aqueous polyurethane resin, Tg: 42 ° C.)
Z2: Bayronal MD-1100 (trade name, manufactured by Toyobo Co., Ltd., water-based polyester resin)
Z3: Adeka Resin EM-0718 (trade name, ADEKA Co., Ltd., aqueous epoxy resin)
Z4: Hydran AP-10 (trade name, manufactured by Dainippon Ink & Chemicals, water-based polyurethane resin, Tg: 27 ° C.)
Z5: Hydran AP-30 (trade name, manufactured by Dainippon Ink and Chemicals, water-based polyurethane resin, Tg: 61 ° C.)
Z6: Hydran HW-340 (trade name, manufactured by Dainippon Ink & Chemicals, water-based polyurethane resin, Tg: 7 ° C.)
Z7: Hydran HW-350 (trade name, manufactured by Dainippon Ink & Chemicals, water-based polyurethane resin, Tg: 57 ° C.)
Z8: Superflex 110 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin, Tg: 46 ° C.)
Z9: Superflex 130 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin, Tg: 96 ° C.)
Z10: Superflex 600 (trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., water-based polyurethane resin, Tg: 70 ° C.)

A predetermined amount of these components was blended to prepare a plurality of types of surface treatment compositions. Table 2 shows the composition of each composition. In Table 2, * 1 to * 10 indicate the following contents.
* 1 Titanium-containing aqueous solution T1 to T7 described in the specification text
* 2 Nickel compounds B1 to B3 described in the specification text
* 3 Fluorine-containing compounds C1 to C4 described in the main text of the specification
* 4 Organophosphate compounds D1 and D2 described in the specification text
* 5 Vanadic acid compounds E1, E2 described in the main text of the specification
* 6 Ether-based organic solvents F1 to F5 described in the main text of the specification
* 7 Zirconium carbonate compounds Y1 and Y2 described in the specification text
* 8 Resin components Z1 to Z10 described in the main text of the specification
* 9 Solid content ratio (mass%) in the composition for surface treatment (aqueous treatment liquid)
* 10 Mixing ratio (mass part) with respect to 100 parts by mass in total of components (A) to (E) described in the specification

(Application method)
The composition described in Table 2 was applied to the surface (one side) of any of the plated steel sheets described in Table 1 and dried at 30 to 100 ° C. to obtain test materials (surface-treated plated steel sheets). The coating was performed by the method shown below, and the coating amount per side was 0.2 g / m ² .
Application method 1: After the composition is applied by spraying at a spray pressure of 1 kgf / cm ² , excess liquid is squeezed out so that the liquid film thickness after squeezing with a Ringer roll is 2 μm.
Application method 2: The composition was applied by a roll coater, and each roll load was adjusted so that the liquid film thickness was 5 μm, and the composition was transferred to the steel sheet side.

(Evaluation criteria)
About each test material, the finishing state of the film | membrane and corrosion resistance were evaluated with the following test methods. In addition, blackening resistance, water resistance, and storage stability were also evaluated. The results are shown in Tables 3 and 4 together with the type of composition applied to each test material and the application conditions. In Tables 3 and 4, * 11 and * 12 indicate the following contents.
* 11 Coating method described in the text of the specification * 12 No. of the coated steel sheet described in Table 1 1-8

(1) Finished state of film The finished state of the film was determined according to the following criteria.
○ (good): Unevenness such as dry marks of bubbles is not visually confirmed, and the film is smooth and uniform with no film missing when rubbed with a finger.
Δ (slightly defective): Either unevenness is visually confirmed or the film is missing when rubbed with a finger.
X (defect): Concavities and convexities are confirmed visually, and a film is missing when rubbed with a finger.

(2) Corrosion resistance A salt spray test based on JIS-Z-2371-2000 was performed on the specimens whose end portions and back surface were tape-sealed, and the test time at which the white rust generation area ratio was 5% was measured. The evaluation criteria are as follows.
◎ +: 96 hours or more ◎: 72 hours or more, less than 96 hours ○: 48 hours or more, less than 72 hours Δ: 24 hours or more, less than 48 hours ×: less than 24 hours

(3) Blackening resistance The change in whiteness (L value) when the test material was allowed to stand for 24 hours in a thermo-hygrostat controlled at a temperature of 80 ° C. and a relative humidity of 95% was ΔL (L value after the test). -L value before test). The calculation standard is as follows.
○: ΔL ≧ −10
Δ: −10> ΔL ≧ −15
×: −15> ΔL

(4) Water resistance After adding 100 μL of ion-exchanged water to the test material and leaving it to stand at room temperature for 15 minutes, the water dropped in a furnace set at 100 ° C. is dried and the appearance change before and after the test is visually observed. And evaluated. The evaluation criteria are as follows.
○: No change △: Color tone change only at the edge of water drop ×: Color tone change inside water drop

(5) Storage stability The composition adjusted to a concentration of 12% by mass was left in a constant temperature bath at 40 ° C. for 30 days, and the state of the composition was visually evaluated.
○: No change in the state of the composition is observed.
(Triangle | delta): The viscosity rise of a composition is seen.
X: The composition has a viscosity increase and a gel insoluble matter is generated in the composition.

  Table 3 and Table 4 show the following. First, as shown in Comparative Examples 40 to 44, when a surface treatment film was formed by spray coating using a composition containing a zirconium carbonate compound, the corrosion resistance of the galvannealed steel sheet was inferior.

  Next, as shown in Comparative Examples 15 to 27, when a surface treatment film is formed by a spray coating method using a composition containing a resin component, the finished state of the film of the hot dip galvanized steel sheet is deteriorated and the corrosion resistance is also improved. It was not enough. In addition, as shown in Comparative Example 45, the alloyed hot-dip galvanized steel sheet also had a poor coating finish and corrosion resistance was not sufficient.

  Furthermore, as shown in Comparative Examples 1 to 14 and 28 to 39, when any one of the components (A) to (F) of the composition falls outside the content range defined in the present invention, the hot dip galvanized steel sheet Alternatively, at least one of the finish of the alloyed galvanized steel sheet, corrosion resistance, blackening resistance, water resistance, and storage stability was inferior.

  Moreover, as shown in Comparative Examples 46 to 48, when an ether organic solvent having 3 or less carbon atoms or 7 or more carbon atoms is used, the finished state of the film of the hot dip galvanized steel sheet or the galvannealed steel sheet becomes worse. When the carbon number was 7 or more, the corrosion resistance and water resistance were inferior.

  On the other hand, as shown in Invention Examples 1 to 64, when the surface treatment film is formed by the spray coating method using the composition included in the scope of the present invention, both the hot-dip galvanized steel sheet and the alloyed hot-dip galvanized steel sheet The film finish, corrosion resistance, blackening resistance, water resistance, and storage stability were all good. In particular, the corrosion resistance was very good when applied to galvannealed steel sheets.

  Further, when Invention Examples 1 to 19, 22 to 51, 54 to 64 are compared with Invention Examples 20, 21, 52 and 53, the fluorine-containing compound (C) is obtained from zircon ammonium fluoride and zircon hydrofluoric acid. It has also been found that the corrosion resistance is particularly good when one or two are included.

  In addition, as shown in Comparative Examples 57 and 58 for reference, when applied to a hot-dip galvanized steel sheet by a roll coating method, the component (A) or (C) of the composition is not included in the scope of the present invention. However, the corrosion resistance was not inferior. Furthermore, as shown in Comparative Examples 59 and 60 for reference, when applied by the roll coating method, the finish of the film was not inferior even if the composition contained a resin. In addition, as shown in Reference in Comparative Example 61, when applied to the alloyed hot-dip galvanized steel sheet by a roll coating method, even if the composition does not contain at least one glycol ether organic solvent, The film finish did not decrease and the corrosion resistance of the film was good. From this, it was found that the problem that the corrosion resistance or the film finish is inferior is peculiar to the case of applying by the spray coating method.

  Moreover, as shown in Comparative Examples 49 to 54, even when a composition satisfying the component composition defined in the present invention is applied to a galvanized steel sheet other than the hot dip galvanized steel sheet or the galvannealed steel sheet by a spray coating method, Sufficient corrosion resistance could not be obtained. Therefore, it turned out that this invention is peculiar when forming a surface treatment film | membrane with respect to a hot-dip galvanized steel plate or an alloyed hot-dip galvanized steel plate with these compositions.

  In addition, as shown in Comparative Examples 55 and 56 for reference, when nothing is applied to a hot-dip galvanized steel sheet or an alloyed hot-dip galvanized steel sheet, all of corrosion resistance, blackening resistance, and water resistance are insufficient.

  According to the present invention, sufficient corrosion resistance and good coating appearance (finished state) are exhibited when a surface-treated coating is formed on a surface of a hot dip galvanized steel plate or an alloyed hot dip galvanized steel plate by a spray coating method. It was possible to provide an environmentally applicable surface treatment composition containing no hexavalent chromium.

Claims (4)

Titanium obtained by mixing at least one titanium compound selected from hydrolyzable titanium compounds, low-condensates of hydrolyzable titanium compounds, titanium hydroxide, and low-condensates of titanium hydroxide with hydrogen peroxide water 10 to 45% by mass of the aqueous solution (A) in solid content, 0.01 to 1% by mass of the nickel compound (B) in solid content, and the solid content of the fluorine-containing compound (C). 10 to 20% by mass, 40 to 60% by mass of the organic phosphoric acid compound (D) in the proportion of solids, 0.1 to 30% by mass of the vanadic acid compound (E) in the proportion of solids, carbon 5 to 30 parts by mass of the ether-based organic solvent (F) of formula 4 to 6 in a ratio to the total of 100 parts by mass of the above (A), (B), (C), (D) and (E) And
A composition containing no resin component and zirconium carbonate compound,
A composition for spray coating surface treatment, which is used for forming a surface treatment film by applying at least one surface of a galvanized steel plate which is a hot dip galvanized steel plate or an alloyed hot dip galvanized steel plate by a spray coating method.   2. The spray-coated surface treatment composition according to claim 1, wherein the fluorine-containing compound (C) is at least one selected from zircon ammonium fluoride and zircon hydrofluoric acid.   The spray coating surface treatment composition according to claim 1 or 2 is applied to at least one surface of a galvanized steel sheet or a galvanized steel sheet that is a galvannealed steel sheet or an alloyed hot dip galvanized steel sheet using a ringer roll or air. A method for producing a surface-treated galvanized steel sheet, characterized in that a surface-treated film is formed by reducing the amount applied and drying.   A surface-treated galvanized steel sheet produced by the production method according to claim 3.