JP2018024937A - Surface treated metal plate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treated metal plate excellent in black discoloration resistance and capable of sufficiently suppressing the occurrence of stain and dirt.SOLUTION: The surface treated metal plate comprises a galvanized steel sheet and a surface treated film laminated on at least one surface of the galvanized steel sheet. The surface treated film is constituted of a surface treated composition including: a polyolefin based resin without including ammonia; and colloidal silica having the average particle size of 4-6 nm. The content of the colloidal silica is 10 pts.mass or more and less than 30 pts.mass to 100 pts.mass of the surface treated composition; the coating weight of the surface treated film is 0.4-1.2 g/m; and the amount of sodium ions eluted from the surface treated film is 4 mg/mor less when immersed in deionized water of 70-80°C for 10 minutes.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a surface-treated metal plate and a method for producing the surface-treated metal plate.

It is known that a blackening phenomenon occurs on the surface of a zinc-based plated steel sheet. This blackening phenomenon is a phenomenon in which at least a part of the surface changes to blackish color such as black or brownish brown. Further, this blackening phenomenon is specifically a corrosion phenomenon observed in an initial stage in a corrosive environment before white rust occurs, and is said to occur in a relatively mild corrosive environment. In addition, due to the blackening phenomenon, the surface of the galvanized steel sheet looks blackish because of the stoichiometric composition of Zn _x O _1-x during the oxidation reaction (corrosion reaction) of zinc (Zn) present on the surface. This is believed to be due to the formation of detached amorphous oxide.

  The blackening phenomenon is also said to be a phenomenon that occurs when the oxidation reaction of Zn is halfway. In order to prevent blackening, it is considered that the oxidation reaction should be promoted to some extent. Therefore, it is conceivable to add elements such as Ni, Co, and In to the galvanized layer as elements that moderately promote the oxidation reaction. Examples of such a method include the techniques described in Patent Documents 1 to 4.

  Patent Document 1 contains Ni ions in an amount within the range of 100 to 300 ppm, the content of Pb ions contained as impurities is 0.5 ppm or less, and the ratio of Ni ions to Pb ions in the plating bath It is described that the steel sheet is electrogalvanized in an electrogalvanizing bath in which (Ni ion / Pb ion) exceeds 500, and then a predetermined chromate treatment is performed.

  Patent Document 2 discloses that Ni ions in a galvanizing bath are in a range of 5 to 500 times the amount of Pb ions contained as impurities, 1/25 or less of the amount of Zn ions and 10 g / l or less. It is described that the steel sheet is electrogalvanized in a quantity of electrogalvanizing bath and then given chromate treatment.

  Further, as another method for suppressing the blackening phenomenon, for example, a method of providing a layer containing an element such as Ni or Co on a steel plate can be considered. As such a method, for example, a technique described in Patent Document 3 can be cited.

  Patent Document 3 discloses a steel plate, an electrogalvanized layer formed on the steel plate, a metal layer formed by depositing at least one of Ni and Co on the surface of the electrogalvanized layer, and A chromate-treated electrogalvanized steel sheet comprising a chromate film formed on a metal layer is described.

  Moreover, as a method for improving blackening resistance without deteriorating the corrosion resistance of the chromate-free steel sheet, for example, a technique described in Patent Document 4 can be cited.

  Patent Document 4 includes at least one first element selected from Si, P, As, S, Fe, Co, B, Ge, Mn, Cu, and Zn, and Mo, W, V, and Nb. A zinc-based plated steel sheet containing at least one selected second element and having the second element as a heteropolyacid in the chemical conversion coating is described.

  Moreover, as a chromate-free steel plate excellent in corrosion resistance etc., the technique of patent document 5 and patent document 6 is mentioned, for example.

  Patent Document 5 describes a surface-treated steel material in which a film is formed on a steel sheet using a water-based surface treatment agent containing a water-based resin, colloidal silica, and ammonium vanadate in a predetermined content.

  Further, Patent Document 6 has a base treatment layer containing an organic resin and a silane coupling agent in a predetermined content on a galvanized steel sheet or a zinc alloy plated steel sheet, and further, an organic resin and A surface-treated steel material having an upper film containing a thiocarbonyl group-containing compound at a predetermined content is described.

Japanese Patent Laid-Open No. 2-8374 Japanese Unexamined Patent Publication No. 60-77788 JP-A-10-219494 JP 2012-167326 A JP-A-11-310757 JP 2000-248383 A

  According to Patent Document 1 and Patent Document 2, it is disclosed that the occurrence of the blackening phenomenon of the chromate-treated electrogalvanized steel sheet can be suppressed. However, as described in Patent Document 1 and Patent Document 2, chromate-treated electrogalvanized steel sheets in which elements such as Ni, Co, and In are added to the galvanized layer are present as impurities in the galvanized layer. It is necessary to consider the balance with elements that degrade the corrosion resistance such as Pb, Cu, and Ag. In addition, even if such a chromate-treated electrogalvanized steel sheet is adjusted, the occurrence of uneven discoloration or a decrease in whiteness occurs due to changes in the valence of metal elements and metal elution in a corrosive environment. As a result, poor appearance may occur. Also, chromate-treated electrogalvanized steel sheets, when elements such as Ni, Co, and In are added to the galvanized layer and the oxidation reaction is promoted too much, the corrosion resistance is remarkably reduced and white rust is generated, In some cases, black-brown or grayish-brown unevenness (hereinafter referred to as stain stain) is likely to occur.

  Patent Document 3 discloses that an electrogalvanized steel sheet excellent in blackening resistance can be obtained. According to Patent Document 4, blackening resistance can be improved without deteriorating the corrosion resistance of the chromate-free steel sheet. However, the galvanized steel sheets described in Patent Document 3 and Patent Document 4 are also similar to the chromate-treated electrogalvanized steel sheets described in Patent Document 1 and Patent Document 2, and the valence change of metal elements and metal elution in a corrosive environment. Occurrence of discoloration unevenness or a decrease in whiteness due to, for example, may occur, resulting in poor appearance.

  Moreover, in consideration of the balance of corrosion resistance, blackening resistance, adhesion to the galvanized surface, conductivity of the steel plate, etc., the zinc-based plated steel plate, for example, the zinc-based plated steel plate described in Patent Documents 1 to 4 Furthermore, it is also conceivable to form an inorganic-rich film or an organic-rich film with a thin film of about 0.5 to 1 μm as the surface treatment film. Specifically, it is conceivable to provide the films described in Patent Document 5 and Patent Document 6 as surface treatment films. According to Patent Document 5 and Patent Document 6, it is disclosed that a surface-treated steel sheet having excellent corrosion resistance can be obtained.

  However, there are cases where the blackening phenomenon cannot be sufficiently suppressed only by providing such a surface treatment film. Further, not only the blackening phenomenon cannot be sufficiently suppressed, but also stain stains are likely to occur. .

  In particular, stain stains that are likely to occur in a hot and humid environment significantly impair the appearance of the product and reduce the value of the product. For this reason, it is more demanded to suppress not only the blackening phenomenon but also the occurrence of stains.

  This invention is made | formed in view of this situation, Comprising: It aims at providing the surface treatment metal plate which was excellent in blackening-proof property, and fully suppressed generation | occurrence | production of a stain stain.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below.

A surface-treated metal plate according to an aspect of the present invention includes a zinc-based plated steel sheet and a surface-treated film laminated on at least one surface of the zinc-based plated steel sheet, and the surface-treated film contains ammonia. The surface treatment composition comprises a non-polyolefin resin and colloidal silica having an average particle diameter of 4 to 6 nm, and the content of the colloidal silica is 10 parts by mass with respect to 100 parts by mass of the surface treatment composition. It is less than 30 parts by mass, the adhesion amount of the surface treatment film is 0.4 to 1.2 g / m ² , and is eluted from the surface treatment film when immersed in deionized water at 70 to 80 ° C. for 10 minutes. The amount of sodium ions to be produced is 4 mg / m ² or less.

  According to such a configuration, a surface-treated metal plate excellent in blackening resistance and sufficiently suppressing the occurrence of stain stains, that is, a surface-treated metal plate excellent in blackening resistance and stain stain resistance is provided. be able to.

  In the surface-treated metal plate, it is preferable that the surface treatment composition further includes a crosslinking agent and a lubricant.

  According to such a configuration, a surface-treated metal plate that is more excellent in blackening resistance and stain stain resistance can be obtained.

  Moreover, in the said surface treatment metal plate, it is preferable that content of the said crosslinking agent is 5-8.5 mass parts with respect to 100 mass parts of the said surface treatment compositions.

  According to such a configuration, a surface-treated metal plate that is more excellent in blackening resistance and stain stain resistance can be obtained.

  Moreover, in the said surface treatment metal plate, it is preferable that content of the said lubricant is 2-5 mass parts with respect to 100 mass parts of said surface treatment compositions.

  According to such a configuration, a surface-treated metal plate that is more excellent in blackening resistance and stain stain resistance can be obtained.

  In the surface-treated metal plate, the colloidal silica is preferably colloidal silica containing ammonia as a dispersant.

  According to such a configuration, a surface-treated metal plate that is more excellent in blackening resistance and stain stain resistance can be obtained.

  In the surface-treated metal plate, the polyolefin resin preferably contains a copolymer of an α, β-unsaturated carboxylic acid and an olefin.

  According to such a configuration, a surface-treated metal plate that is more excellent in blackening resistance and stain stain resistance can be obtained.

  The method for producing a surface-treated metal sheet according to another aspect of the present invention is a method for producing a surface-treated metal sheet for producing the surface-treated metal sheet, the step of preparing the surface treatment composition, and the surface Applying the treatment composition onto at least one surface of the zinc-based plated steel sheet; and drying the surface treatment composition to form the surface treatment film on at least one surface of the zinc-based plated steel sheet. Forming.

  According to such a configuration, a surface-treated metal plate that is excellent in blackening resistance and sufficiently suppresses the occurrence of stain stains, that is, a surface-treated metal plate that is excellent in blackening resistance and stain stain resistance is produced. be able to.

  According to the present invention, it is possible to provide a surface-treated metal plate that is excellent in blackening resistance and sufficiently suppresses the occurrence of stains and a method for producing the surface-treated metal plate.

FIG. 1A is a schematic view showing a surface-treated metal plate in which a surface-treated film is provided on a zinc-based plated steel sheet. FIG. 1B is a schematic diagram illustrating a state in which an amorphous oxide is generated on the surface-treated metal plate illustrated in FIG. 1A. FIG. 2 is a schematic view showing the state of colloidal silica. FIG. 3A is a schematic view showing a state in which stain stain has started to occur in a surface-treated metal plate in which a surface-treated film is provided on a zinc-based plated steel sheet. FIG. 3B is a schematic view showing a state in which stain stain is diffused in a surface-treated metal plate in which a surface-treated film is provided on a zinc-based plated steel sheet. FIG. 4 is a schematic view showing a state in which the occurrence of stains is suppressed in a surface-treated metal plate in which a surface-treated film is provided on a zinc-based plated steel sheet. FIG. 5 is a schematic view showing a friction coefficient measuring apparatus for evaluating lubricity. FIG. 6 is a graph showing the change over time in the white rust occurrence rate in the evaluation of the SST flat plate. FIG. 7 is a graph showing the transition of the white rust occurrence rate with respect to the number of cycles in the evaluation of the SST cycle. FIG. 8 is a graph showing the relationship between the Na ⁺ elution amount from the surface treatment film and the stain stain.

  According to the study of the present inventor, the reason why the blackening phenomenon may not be sufficiently suppressed even if a surface treatment film is formed on a zinc-based plated steel sheet is presumed to be as follows.

  First, as shown in FIG. 1A, even when the surface treatment film 11 is provided on the zinc-based plated steel sheet 12, the barrier properties such as oxygen permeability and water vapor permeability may be improved halfway. In such a case, as shown in FIG. 1B, an oxidation reaction occurs in a state where oxygen is insufficiently supplied to the surface of the zinc-based plated steel sheet 12, and as described above, the amorphous oxide is formed on the zinc-based plated steel sheet 12. 13 will be generated. That is, the blackening phenomenon occurs in the surface-treated metal plate 10 in which the surface-treated film 11 is provided on the zinc-based plated steel plate 12. FIG. 1A is a schematic view showing a surface-treated metal plate 10 in which a surface-treated film 11 is provided on a zinc-based plated steel plate 12. FIG. 1B is a schematic view showing a state in which the amorphous oxide 13 is generated on the surface-treated metal plate 10 shown in FIG. 1A.

  In addition, the surface-treated metal plate provided with a surface-treated film on a zinc-based plated steel sheet may not be able to sufficiently suppress not only the blackening phenomenon but also stain stains. It has been considered that the stain stain is caused by acceleration of the corrosion reaction that causes the blackening phenomenon due to the deterioration of the barrier property due to the surface treatment film in a high-temperature and high-humidity environment. In the study leading to the present invention, it has been found that the occurrence of stains is not limited to such a case, and can be generated by different mechanisms. Specifically, it is as follows.

  First, the inventors focused on the fact that when colloidal silica is included in the surface treatment film, the occurrence of stain stains may not be sufficiently suppressed. The surface-treated metal plate provided with such a surface-treated film was allowed to stand for 168 hours in a constant temperature and humidity tester set to an environment of, for example, a temperature of 65 ° C. and a humidity of 95%, and stains were generated. The surface-treated metal plate on which the stain was generated is marked with a marking on the surface-treated film, and an electron beam microanalyzer (EPMA, JXA-8100 manufactured by JEOL Ltd.) is used to create a surface. Analysis (mapping / field of view 8 × 8 mm) was performed. As a result of this analysis, it was found that the Na element was concentrated in the spot where the stain was generated. From this, the inventor inferred that the cause of the stain stain was due to the presence of Na element. When the cause of the concentration of Na element was further examined, the present inventor paid attention to colloidal silica contained in the surface treatment film, and presumed that the mechanism for causing stain stain was as follows. did.

First, in a high-temperature and high-humidity environment, a local battery is formed by extremely early corrosion on the surface of the galvanized layer provided with the surface treatment film. As shown in FIG. 2, the colloidal silica contained in the surface treatment film generally contains sodium containing sodium as a dispersant, that is, colloidal silica stabilized with Na ions. This means that colloidal silica is generally produced from sodium silicate as the raw material, and most of the sodium is removed by cation exchange, but sodium is used to form a stable sol of SiO _2. This is because it is difficult to remove completely. FIG. 2 is a schematic view showing the state of colloidal silica. When such colloidal silica is contained in the surface treatment film, the surface treatment film contains Na element derived from the colloidal silica. And the Na element derived from the colloidal silica contained in this surface treatment film is concentrated in the cathode part of the battery, and the initial corrosion is gradually promoted to form an amorphous oxide (amorphous zinc oxide) on the galvanized layer. Produces. That is, as shown in FIG. 3A, in the surface-treated metal plate 10 in which the surface treatment film 11 including the colloidal silica 14 is provided on the zinc-based plated steel plate 12, Na ions contained in the colloidal silica 14 are contained in the zinc-based plated steel plate 12. It moves to the surface of the galvanized layer, and the amorphous oxide 13 is partially formed. When the amorphous oxide 13 is the starting point and corrosion progresses, the irregular oxide 13 diffuses unevenly at the interface between the galvanized steel sheet 12 and the surface treatment film 11 as shown in FIG. 3B. To do. The irregularly shaped amorphous oxide 13 diffuses and looks like stains. Based on such a mechanism, it was speculated that stains were generated on the surface-treated metal plate provided with the surface-treated film containing colloidal silica as described above. FIG. 3A is a schematic diagram showing a state in which stain stain has started to occur in the surface-treated metal plate 10 in which the surface-treated film 11 is provided on the zinc-based plated steel sheet 12. FIG. 3B is a schematic view showing a state in which stain stain is diffused in the surface-treated metal plate 10 in which the surface-treated film 11 is provided on the zinc-based plated steel plate 12.

  Therefore, when the amount of Na element contained in the surface treatment film is reduced, the inventor reduces the amorphous oxide 13 that is partially formed as shown in FIG. We thought that we could suppress effectively. FIG. 4 is a schematic view showing a state in which the occurrence of stains is suppressed in the surface-treated metal plate 10 in which the surface-treated film 11 is provided on the zinc-based plated steel sheet 12.

Moreover, when the aqueous emulsion contained as a base in the surface treatment composition uses ammonia as a neutralizing agent when the emulsion is formed, this ammonia is contained in the surface treatment composition. This ammonia reacts with the galvanized layer to partially produce zinc oxide (ZnO), zinc hydroxide (Zn (OH) ₂ ), etc., resulting in deterioration of corrosion resistance, blackening, and occurrence of stains. I found it to promote more.

  Therefore, the present inventor uses less ammonia as the resin contained in the surface treatment composition used when forming the surface treatment film, and the amount of ammonia contained in the surface treatment composition is reduced. It was thought that corrosion resistance, blackening resistance, and stain stain resistance could be improved.

  The present inventor has arrived at the present invention as described below based on the above-described studies.

As shown in FIGS. 1A and 3A, the surface-treated metal plate according to one embodiment of the present invention is a surface treatment laminated on a zinc-based plated steel plate 12 and at least one surface of the zinc-based plated steel plate 12. And a coating 11. The surface treatment film 11 is composed of a surface treatment composition containing a polyolefin-based resin not containing ammonia and colloidal silica having an average particle diameter of 4 to 6 nm. And content of the said colloidal silica is 10 mass parts or more and less than 30 mass parts with respect to 100 mass parts of said surface treatment compositions. Moreover, the adhesion amount of the said surface treatment film | membrane is 0.4-1.2 g / m < ² >. Moreover, the amount of sodium ions eluted from the surface treatment film when immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m ² or less.

  Such a surface-treated metal plate is excellent in blackening resistance and can sufficiently suppress the occurrence of stain stains. Moreover, it is excellent also in adhesiveness with a zinc plating layer. This is considered to be due to the following.

First, since such a surface treatment film 11 contains a polyolefin resin not containing ammonia, the amount of ammonia contained in the surface treatment composition is reduced. Therefore, it is thought that generation | occurrence | production of the fall of corrosion resistance by the reaction of ammonia and a zinc plating layer, blackening, and a stain stain can be suppressed. Furthermore, since the average particle diameter of the colloidal silica to be contained is as small as 4 to 6 nm, the dispersibility and activity of the colloidal silica are increased, the barrier property of the surface treatment film is increased, the corrosion resistance can be increased, and the galvanized layer It is thought that the adhesiveness can be improved. Such colloidal silica is contained so as to be 10 parts by mass or more and less than 30 parts by mass with respect to 100 parts by mass of the surface treatment composition, and the adhesion amount is 0.4 to 1.2 g / m ² . Thus, it is thought that the effect containing colloidal silica, such as improving corrosion resistance and adhesiveness with a zinc plating layer, can be suitably exhibited by forming a surface treatment film. Furthermore, the amount of sodium ions eluted from the surface treatment film when the surface treatment film is immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m ² or less. Thus, when there is little quantity of sodium ion eluted from a surface treatment membrane | film | coat, as mentioned above, it is thought that generation | occurrence | production of a stain | pollution | contamination dirt can be suppressed. For these reasons, the surface-treated metal plate according to the present embodiment is excellent in blackening resistance and can sufficiently suppress the occurrence of stain stains. Moreover, it is excellent also in adhesiveness (tape peeling resistance) with a zinc plating layer.

  The zinc-based plated steel sheet is not particularly limited, and may be a zinc-only plated steel sheet or a zinc-based alloy-plated steel sheet such as zinc-Ni, zinc-Fe, and zinc-Al. The plating method is not particularly limited, and may be a galvanized steel sheet obtained by any of a hot dipping method, an electroplating method, a vapor deposition method and the like. Specific examples of the zinc-based plated steel sheet include a hot-dip galvanized steel sheet (GI), an alloyed hot-dip Zn-Fe-plated steel sheet (GA), an alloyed hot-dip Zn-5% Al-plated steel sheet (GF), and electrogalvanizing. A steel plate (EG), an electric Zn-Ni alloy plating steel plate, etc. are mentioned. Among these, an electrogalvanized steel sheet (EG) is preferable.

  As described above, the surface treatment film is composed of a surface treatment composition containing a polyolefin-based resin not containing ammonia and colloidal silica having an average particle diameter of 4 to 6 nm.

The polyolefin resin is not particularly limited as long as it is a polyolefin resin not containing ammonia. As the polyolefin resin, specifically, a polyolefin resin emulsified without containing ammonia, that is, a polyolefin resin emulsified without using ammonia as a neutralizing agent at the time of emulsion production, etc. It is done. Moreover, as such polyolefin resin, the polyolefin resin emulsified including at least one of an organic basic amine and a metal ion is mentioned, for example. That is, examples of the polyolefin resin include a polyolefin resin that has been emulsified using at least one of an organic basic amine and a metal ion as a neutralizing agent at the time of producing the emulsion. If the polyolefin resin does not contain ammonia such as the polyolefin resin emulsified without containing ammonia, the zinc oxide produced when the polyolefin resin emulsified with ammonia is used ( Generation of ZnO) or zinc hydroxide (Zn (OH) ₂ ) can be suppressed. Accordingly, it is possible to promote the deterioration of corrosion resistance, blackening, and the occurrence of stains.

The polyolefin resin is not particularly limited as long as it is a polyolefin resin that does not contain ammonia, but the water vapor permeability when formed into a film is preferably 100 g / m ² / day or less, and 50 g / m. More preferably, it is ² / day or less. The water vapor permeability is, for example, the water vapor permeability defined by JIS K 7129. Examples of the measuring method include a method of preparing a film of about 18 μm and measuring the water vapor permeability of the film by a cup method in accordance with JIS Z 0208. If the water vapor permeability is too high, adding the colloidal silica to increase the corrosion resistance and the like will increase the water vapor permeability of the obtained surface treatment film, and the effect of improving the corrosion resistance cannot be obtained. There is.

  The polyolefin resin is not particularly limited as long as it is a polyolefin resin not containing ammonia, but is a copolymer of an α, β-unsaturated carboxylic acid and an olefin (olefin-α, β-unsaturated carboxylic acid). A copolymer). Further, in the olefin-α, β-unsaturated carboxylic acid copolymer, it is considered that the structural unit derived from α, β-unsaturated carboxylic acid improves the adhesion between the zinc plating and the surface treatment film. It is done. Therefore, by including the olefin-α, β-unsaturated carboxylic acid copolymer, the barrier property of the surface treatment film is improved without impairing the dispersion stability of the colloidal silica in the surface treatment composition. Can do. For this reason, the penetration of water and oxygen into the surface treatment film is reduced, and the corrosion resistance and blackening resistance can be further improved.

  The olefin-α, β-unsaturated carboxylic acid copolymer (hereinafter also simply referred to as “olefin-acid copolymer”) is a copolymer of an α, β-unsaturated carboxylic acid and an olefin. And as for the olefin-acid copolymer here, it is preferable that the structural unit derived from an olefin is 50 mass% or more in the said olefin-acid copolymer. That is, in the olefin-acid copolymer, the structural unit derived from α, β-unsaturated carboxylic acid is preferably 50% by mass or less in the olefin-acid copolymer.

  The olefin-acid copolymer only needs to be copolymerized with an olefin and an α, β-unsaturated carboxylic acid. By copolymerizing the olefin and the α, β-unsaturated carboxylic acid by a known method. Can be manufactured. The olefin-acid copolymer is commercially available.

  It does not specifically limit as an olefin which can be used for manufacture of the said olefin-acid copolymer, Ethylene, propylene, etc. are preferable and ethylene is more preferable. In the olefin-acid copolymer, the structural unit derived from the olefin may be derived from only one olefin, or may be derived from two or more olefins.

  The α, β-unsaturated carboxylic acid that can be used for the production of the olefin-acid copolymer is not particularly limited, and examples thereof include ethylenic α, β-unsaturated carboxylic acid. Specific examples of the α, β-unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, and isocrotonic acid, and dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid. Can be mentioned. As the α, β-unsaturated carboxylic acid, one kind may be used alone, or two or more kinds may be used in combination. As the α, β-unsaturated carboxylic acid, among the compounds exemplified above, acrylic acid and methacrylic acid are preferable, and acrylic acid is more preferable. In the olefin-acid copolymer, the structural unit derived from the α, β-unsaturated carboxylic acid may be derived from only one type of α, β-unsaturated carboxylic acid, or two or more types. The α, β-unsaturated carboxylic acid may be used.

  The structural unit derived from the α, β-unsaturated carboxylic acid in the olefin-acid copolymer is considered to have an effect of improving the adhesion between the galvanizing and the surface treatment film as described above. In order to effectively exhibit this action, the olefin-acid copolymer has a structural unit derived from the α, β-unsaturated carboxylic acid in an amount of 5% by mass or more in the olefin-acid copolymer. It is preferably 10% by mass or more. Moreover, as above-mentioned, it is preferable that the upper limit of content of the structural unit derived from the said (alpha), (beta)-unsaturated carboxylic acid is 50 mass% or less, and it is 30 mass% or less from a corrosion-resistant viewpoint. More preferably, it is more preferably 25% by mass or less.

  The olefin-acid copolymer is within the range where the effects of the present invention are achieved, specifically, within a range where the corrosion resistance and blackening resistance are excessively lowered and the effects of the present invention are not sufficiently exhibited. And a structural unit derived from a monomer (other monomer) other than the olefin and the α, β-unsaturated carboxylic acid. The structural unit derived from the other monomer is preferably 10% by mass or less, more preferably 5% by mass or less, and most preferably 0% by mass in the olefin-acid copolymer. preferable. That is, the most preferable one is a copolymer composed of only the structural unit derived from the olefin and the structural unit derived from the α, β-unsaturated carboxylic acid. As the olefin-acid copolymer, specifically, an ethylene-acrylic acid copolymer is preferable.

  Moreover, the said olefin-acid copolymer may be used individually by 1 type in the olefin-acid copolymer mentioned above, and may be used in combination of 2 or more type.

  Since the olefin-acid copolymer has a carboxyl group in the molecule, the polyolefin resin is emulsified (water dispersion) by neutralization with the organic basic amine or metal ion. be able to.

  Although it does not specifically limit as an organic basic amine used as a neutralizing agent at the time of this emulsion manufacture, It is preferable that a boiling point is 100 degrees C or less, and it is more preferable that it is 90 degrees C or less. If the boiling point is within the above range, the organic basic amine is reduced in corrosion resistance and black resistance because it is volatilized in drying when forming the surface treatment film and hardly remains in the formed surface treatment film. Less likely to cause stains. Therefore, the surface-treated metal plate excellent in corrosion resistance, black resistance, and stain stain resistance can be obtained. The boiling point of the organic basic amine is preferably 70 ° C. or higher, more preferably 80 ° C. or higher, from the viewpoint of workability.

  Specific examples of the organic basic amine include triethylamine, N, N-dimethylbutylamine, N, N-dimethylallylamine, N-methylpyrrolidine, tetramethyldiaminomethane, and tertiary amines such as trimethylamine, N-methyl Secondary amines such as ethylamine, diisopropylamine, and diethylamine, and primary amines such as propylamine, t-butylamine, sec-butylamine, isobutylamine, 1,2-dibutylpropylamine, and 3-pentylamine. As the organic basic amine, among the amines exemplified above, a tertiary amine is preferable, and triethylamine is more preferable. Moreover, the said organic basic amine may be used individually by 1 type, and may be used in combination of 2 or more type.

  The amount of the organic basic amine used is not particularly limited as long as the polyolefin resin is suitably emulsified. As the usage-amount of the said organic basic amine, it is 0.2-0.8 mol with respect to 1 mol of carboxyl groups in the said olefin-acid copolymer (20-80 mol% with respect to the said carboxyl group), for example. ) Is preferable. Moreover, as a minimum of the usage-amount of the said organic basic amine, it is preferable that it is 0.2 mol or more with respect to 1 mol of said carboxyl groups, and it is more preferable that it is 0.3 mol or more. Moreover, as an upper limit of the usage-amount of the said organic basic amine, it is preferable that it is 0.8 mol or less with respect to 1 mol of said carboxyl groups, It is more preferable that it is 0.6 mol or less, 0.5 More preferably, it is less than or equal to mol. If the usage-amount of the said organic basic amine is in the said range, there exists an effect that it is excellent in the corrosion resistance of a surface-treated steel plate, blackening resistance, and adhesiveness (tape peeling resistance) with a galvanization layer. Moreover, when there is too little usage-amount of the said organic basic amine, there exists a tendency for the particle | grains of the polyolefin resin in an emulsion to become large, and to become difficult to show | play such an effect. Moreover, when there is too much usage-amount of the said organic basic amine, there exists a possibility that an emulsion may thicken and gelatinize.

  Moreover, it does not specifically limit as a metal ion used as a neutralizing agent at the time of the said emulsion manufacture, From a viewpoint of the hardness improvement of a surface treatment film | membrane, it is preferable that it is a monovalent metal ion. Specifically, the metal ion preferably contains at least one selected from sodium ions, potassium ions, and lithium ions. As a compound which produces | generates this metal ion in the said surface treatment composition, the hydroxide, carbonate, oxide, etc. containing these metal ions are mentioned. Specific examples of such a compound include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and among these, sodium hydroxide is preferable.

  The usage-amount of the compound which produces | generates the said metal ion in the said surface treatment composition will not be specifically limited if the said polyolefin resin is emulsified suitably. As the usage-amount of the said compound, it is 0.02-0.4 mol (2-40 mol% with respect to the said carboxyl group) with respect to 1 mol of carboxyl groups in the said olefin-acid copolymer, for example. It is preferable. Moreover, as a minimum of the usage-amount of the said compound, it is preferable that it is 0.02 mol or more with respect to 1 mol of said carboxyl groups, It is more preferable that it is 0.03 mol or more, 0.1 mol or more More preferably it is. Moreover, as an upper limit of the usage-amount of the said compound, it is preferable that it is 0.4 mol or less with respect to 1 mol of said carboxyl groups, and it is more preferable that it is 0.2 mol or less. If the amount of the compound used is too small, the emulsion stability tends to be insufficient. Moreover, when there is too much usage-amount of the said compound, there exists a tendency for corrosion resistance to fall.

  The preferred range of the amount of each of the compounds that produce the organic basic amine and the metal ion in the surface treatment composition is as described above, and these are all carboxyl groups in the olefin-acid copolymer. It is used to neutralize the group and emulsify the polyolefin resin. Accordingly, if the total amount (neutralization amount) of these is too large, the viscosity of the emulsion may rapidly increase and solidify. Furthermore, since excessive alkali content causes corrosion resistance and blackening resistance deterioration, a large amount of energy is required for volatilization. On the other hand, if the total amount (neutralization amount) is too small, the emulsifiability may be insufficient. From these things, the total amount of the compound which produces | generates the said organic basic amine and the said metal ion in the said surface treatment composition is 0.3 ~ with respect to 1 mol of carboxyl groups in the said olefin-acid copolymer. It is preferable that it is 1.0 mol (30-100 mol% with respect to the said carboxyl group).

  Polyolefin resins emulsified containing at least one of organic basic amines and metal ions form intermolecular associations by ion clusters, and are resistant to corrosion, blackening, and adhesion to galvanized layers (tape resistance) A surface treatment film excellent in properties). In order to form a tougher surface treatment film, the surface treatment composition may contain a cross-linking agent capable of cross-linking polyolefin resins by chemical bonding utilizing a reaction between functional groups. This cross-linking agent is a cross-linking agent for cross-linking polyolefin resins, that is, the internal cross-linking agent is a cross-linking agent that cross-links the resin constituting the emulsion at the time of preparing the emulsion, and is also referred to herein as an internal cross-linking agent.

  The internal cross-linking agent is not particularly limited as long as it can cross-link polyolefin resins, and examples thereof include a cross-linking agent having two or more functional groups capable of reacting with a carboxyl group in the molecule. Specific examples of the internal crosslinking agent include a glycidyl group-containing crosslinking agent having two or more glycidyl groups in the molecule and an aziridinyl group-containing crosslinking agent having two or more aziridinyl groups in the molecule. Examples of the glycidyl group-containing crosslinking agent include sorbitol polyglycidyl ether, (poly) glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, (poly) ethylene glycol di- Examples thereof include polyglycidyl ethers such as glycidyl ether, polyglycidyl amines and the like. Examples of the aziridinyl group-containing crosslinking agent include 4,4′-bis (ethyleneiminocarbonylamino) diphenylmethane, N, N′-hexamethylene-1,6-bis (1-aziridinecarboxyamide), N, N. Bifunctional aziridine compounds such as' -diphenylmethane-4,4'-bis (1-aziridinecarboxamide) and toluenebisaziridinecarboxyamide, tri-1-aziridinylphosphine oxide, tris [1- (2- Methyl) aziridinyl] phosphine oxide, trimethylolpropane tris (β-aziridinylpropionate), tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, and tetramethylpropanetetraazi Tri- or higher functional aziridine compounds such as lysinyl propionate And derivatives of the aziridine compounds. As the internal crosslinking agent, among the exemplified crosslinking agents, a bifunctional or higher-functional aziridine compound is preferable, a bifunctional aziridine compound is more preferable, and 4,4′-bis (ethyleneiminocarbonylamino) diphenylmethane is further preferable. Moreover, the said internal crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  The amount of the internal cross-linking agent used is preferably 1 to 20% by mass and more preferably 5 to 10% by mass with respect to the polyolefin resin. In addition, the usage-amount here is a ratio with respect to 100 mass% of solid content of the said polyolefin resin. If the amount of the internal cross-linking agent is too small, the effect of adding the internal cross-linking agent tends to be insufficient. That is, the cross-linking effect due to chemical bonding becomes insufficient, and the effect of improving the corrosion resistance and tape peel resistance tends to be hardly exhibited. On the other hand, if the amount of the internal cross-linking agent is too large, the cross-linking density of the surface-treated film becomes too high and the hardness is increased, and cracks are generated because it becomes impossible to follow the deformation during the press working of the surface-treated metal plate. There is a risk of reducing the corrosion resistance.

  The amount of the olefin-based resin is preferably such that the olefin-based resin constitutes the balance other than colloidal silica, a cross-linking agent that cross-links the surface-treated film, and a lubricant, which will be described later, in the surface treatment composition. If it is such an addition amount, it will not specifically limit. The amount of the olefin resin added is preferably, for example, 56.5 to 90 parts by mass with respect to 100 parts by mass of the surface treatment composition. In addition, the addition amount here is solid content ratio.

First, the colloidal silica has an average particle diameter of 4 to 6 nm. Further, the colloidal silica is required to have a small amount of sodium ions eluted from the surface treatment film based on the above-described consideration. Specifically, the colloidal silica is such that the amount (elution amount) of sodium ions eluted from the surface treatment film when immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m ² or less. Is colloidal silica. The colloidal silica is not particularly limited as long as it is such colloidal silica.

Specifically, the colloidal silica preferably includes colloidal silica containing ammonia as a dispersant. Colloidal silica containing ammonia as such a dispersant, that is, colloidal silica stabilized with NH ₄ ⁺ ions (ammonia stabilized type) is commercially available. By using colloidal silica containing ammonia as such a dispersant, as described above, it is a general colloidal silica, as compared with the case where only colloidal silica containing sodium as a dispersant (sodium-stabilized type) is used. The amount of sodium in the surface treatment film can be reduced. Therefore, a surface-treated film with a reduced amount of elution can be obtained.

  First, the colloidal silica has an average particle diameter of 4 to 6 nm as described above. If the colloidal silica is too large, the corrosion resistance, tape peel resistance and the like are lowered, and the adhesion (paintability) with the coating film to be coated on the surface-treated metal plate tends to be lowered. This is presumably because the dispersibility and activity of the colloidal silica in the surface treatment film are lowered, the barrier property of the surface treatment film is lowered, and the elution amount of the colloidal silica in a corrosive environment is lowered. Therefore, by using the colloidal silica having the particle diameter as described above, a surface-treated metal plate excellent in corrosion resistance, paintability, tape peel resistance, film hardness, and workability of the surface-treated film can be obtained. Specific examples of colloidal silica having an average particle size of 4 to 6 nm include Snowtech NXS (ST-NXS, ammonia stabilized type) and Snowtech XS (ST-XS, sodium) manufactured by Nissan Chemical Industries, Ltd. Stabilization type). When sodium-stabilized ST-XS is used, it is preferably used in combination with ammonia-stabilized ST-NXS. The average particle size of the colloidal silica here is, for example, measured by the Sears method when the average particle size is about 1 to 10 nm, and measured by the BET method when the average particle size is about 10 to 100 nm. Value and the like. Moreover, when a notarized value is described in the manufacturer's pamphlet, the notarized value is used as the average particle diameter of the colloidal silica here.

Further, as described above, the amount of sodium ions eluted from the surface treatment film (elution amount) when immersed in deionized water at 70 to 80 ° C. for 10 minutes is preferably small. It has been found that if it is 4 mg / m ² or less, stain stain can be suitably suppressed. The elution amount is more preferably 3.8 mg / m ² or less, and further preferably 3.5 mg / m ² or less. If it is in such a range, not only can stain | pollution | contamination stain | pollution | contamination be suppressed suitably, but corrosion resistance, blackening-proof property, tape peeling resistance, etc. can be improved further. The smaller the elution amount, the better. However, due to the characteristics of colloidal silica, the limit is about 1 mg / m ² , and the lower limit of the elution amount is preferably 1 mg / m ² or more. In addition, as for the elution amount here, the value measured as follows is mentioned, for example. The surface-treated metal plate is immersed in deionized water at 70 to 80 ° C. for 10 minutes. The amount of sodium ions contained in the liquid in which the surface-treated metal plate is immersed is measured using ion chromatography. The elution amount is calculated from the measured amount of sodium ions and the area of the surface-treated metal plate. As ion chromatography, for example, ICS-5000 + manufactured by Thermo Fisher Scientific Co., Ltd. can be used.

  Moreover, the minimum of the addition amount of the said colloidal silica is 10 mass parts or more with respect to 100 mass parts of the said surface treatment composition, It is preferable that it is 15 mass parts or more, It is more preferable that it is 20 mass parts or more. preferable. Moreover, the upper limit of the addition amount of the said colloidal silica is less than 30 mass parts with respect to 100 mass parts of said surface treatment compositions, and it is preferable that it is 28 mass parts or less. In addition, the addition amount here is solid content ratio. The reason why the corrosion resistance and blackening resistance are improved by adding colloidal silica to the surface treatment film is that the colloidal silica dissolves and elutes in a corrosive environment, resulting in pH buffering and passive film formation. It is assumed that For this reason, when there is too little addition amount of colloidal silica, this effect | action cannot fully be exhibited, corrosion resistance falls, and there exists a tendency for adhesiveness with the galvanization surface to also fall. On the other hand, when the amount of colloidal silica added is too large, the amount of resin added decreases, so that the surface-treated film becomes brittle and cracks tend to occur. For this reason, reduction in blackening resistance, adhesion to the galvanized surface, and paintability can also be reduced. Therefore, when the addition amount of the colloidal silica is within the above range, a surface-treated metal plate excellent in corrosion resistance and adhesion to the galvanized surface can be obtained.

  In addition to the resin and the colloidal silica, the surface treatment film preferably contains a crosslinking agent and a lubricant for crosslinking the surface treatment film.

  By including the cross-linking agent, the corrosion resistance, tape peel resistance, and lubricity of the surface treatment film can be improved. This cross-linking agent is a cross-linking agent that cross-links the surface-treated film, that is, a cross-linking agent that cross-links the resin that constitutes the surface-treated film when the surface-treated film is formed.

  The external crosslinking agent is not particularly limited as long as it can crosslink the surface treatment film, but an epoxy crosslinking agent is preferably used from the viewpoint of reactivity. Examples of the epoxy-based crosslinking agent include sorbitol polyglycidyl ether, (poly) glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, and (poly) ethylene glycol diester. And polyglycidyl ethers such as glycidyl ether; polyglycidyl amines and the like. As such an epoxy-type crosslinking agent, for example, Epicron CR5L and Epicron CR75 manufactured by DIC Corporation are available. Moreover, the said external crosslinking agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  The amount of the external cross-linking agent added is not particularly limited, but the lower limit thereof is preferably 5 parts by mass or more, for example, 6.5 parts by mass or more with respect to 100 parts by mass of the surface treatment composition. It is more preferable that Moreover, it is preferable that the upper limit of the addition amount of the said external crosslinking agent is 8.5 mass parts or less with respect to 100 mass parts of said surface treatment compositions. In addition, the addition amount here is solid content ratio. If the amount of the external cross-linking agent added is too small, the corrosion resistance, blackening resistance, tape peel resistance, and lubricity tend to decrease. Moreover, when there is too much addition amount of the said external crosslinking agent, there exists a tendency for a coating property to fall. Further, if the external cross-linking agent is added too much, self-crosslinking of the external cross-linking agent may occur, but if the addition amount of the external cross-linking agent is within the above range, it is preferably suppressed while suppressing it. The crosslinking reaction can be allowed to proceed. That is, when the addition amount of the external cross-linking agent is within the above range, the cross-linking reaction proceeds sufficiently, and the corrosion resistance and blackening resistance of the surface treatment film can be improved. Furthermore, since the hardness of the surface treatment film is increased, lubricity and workability are also improved.

  When the lubricant is contained, the dynamic friction coefficient of the surface treatment film is reduced, the workability is improved, and wrinkles are less likely to occur.

  The lubricant is not particularly limited. For example, polyolefin wax such as polyethylene, polyethylene oxide, and polypropylene; fluorine resin such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and tetrafluoroethylene; organic Modified polysiloxane; paraffin wax and the like. Among the above examples, the lubricant is preferably a polyolefin wax, and more preferably a polyethylene wax. Moreover, the said lubricant may be used individually by 1 type, and may be used in combination of 2 or more type.

  In addition, the polyethylene wax is preferably in the form of particles, for example, spherical, and the average particle diameter is preferably 0.1 to 3 μm, more preferably 0.3 to 1 μm. If the polyethylene wax particles (spherical polyethylene wax) are too large, it becomes difficult to uniformly disperse in the surface treatment composition, and the film-forming property is inhibited, so that the corrosion resistance tends to be lowered. On the other hand, if the polyethylene wax particles are too small, there is a tendency that the lubricity cannot be sufficiently improved. The average particle diameter of the polyethylene wax particles can be measured by a Coulter counter method. By using the polyethylene wax particles having the particle diameter as described above, the surface-treated film exists in a spherical shape, and the friction on the surface of the surface-treated film can be effectively reduced, and the occurrence of wrinkles is suppressed. It is effective for. Examples of the polyethylene wax particles include Chemipearl W640, Chemipearl W700, Chemipearl W950, and Chemipearl W900 manufactured by Mitsui Chemicals.

  Moreover, the addition amount of the lubricant is not particularly limited, but the lower limit thereof is preferably 2 parts by mass or more, for example, 2.5 parts by mass or more with respect to 100 parts by mass of the surface treatment composition. More preferably. Moreover, the upper limit of the addition amount of the lubricant is preferably 5 parts by mass or less and more preferably 4 parts by mass or less with respect to 100 parts by mass of the surface treatment composition. In addition, the addition amount here is solid content ratio. If the amount of the lubricant added is too small, the lubricity becomes insufficient, and the bending workability of the surface-treated metal plate tends to decrease. In addition, if the amount of the lubricant added is too large, the lubricant is hydrolyzed in a corrosive environment, and the corrosion resistance, blackening resistance, stain resistance, tape peel resistance, and paintability tend to decrease. is there. Therefore, when the addition amount of the lubricant is within the above range, a surface-treated metal plate excellent in corrosion resistance, blackening resistance, stain resistance and the like can be obtained.

The lower limit of the adhesion amount of the surface treatment film is a 0.4 g / ^{m 2} or more, preferably 0.45 g / ^{m 2} or more, more preferably 0.5 g / ^{m 2} or more. Moreover, the upper limit of the adhesion amount of the surface treatment film is 1.2 g / m ² or less, preferably 0.8 g / m ² or less, and more preferably 0.7 g / m ² or less. When the amount of the surface treatment film attached is too small, the barrier property is deteriorated and the spread of the stain is promoted, so that the stain stain resistance tends to be deteriorated. Moreover, when there is too little adhesion amount of the said surface treatment film | membrane, there exists a tendency which cannot fully improve the corrosion resistance, blackening resistance, tape peeling resistance, etc. of a surface treatment metal plate. In addition, if the surface treatment film is attached too much, the tape peel resistance decreases, and for example, the surface treatment film tends to peel off when bending or pressing the surface-treated metal plate. . Moreover, since there exists a tendency for paintability and electroconductivity to fall, it is not preferable. Therefore, when the adhesion amount of the surface treatment film is within the above range, a surface-treated metal plate excellent in corrosion resistance and blackening resistance can be obtained. In addition, the adhesion amount of a surface treatment film | membrane can be measured as follows, for example. The Si element of colloidal silica (SiO ₂ ) in the surface treatment film can be quantitatively measured with a fluorescent X-ray analyzer and calculated from the measured amount of Si element. Note that the specific gravity of SiO ₂ at this time is 2.2, and the specific gravity of the resin is 1.0.

  The said surface treatment metal plate should just be equipped with the said galvanized steel plate and the said surface treatment film | membrane, and may be provided with the other layer. For example, a ground treatment layer may be provided between the zinc-based plated steel sheet and the surface treatment film. Specifically, in order to improve the interfacial adhesion between the surface of the galvanized steel sheet and the surface treatment film, a reactive base treatment comprising a composition of aluminum biphosphate, acidic colloidal silica, and polyacrylic acid. You may provide the base-treatment layer obtained by implementing. However, unreacted phosphoric acid and the like are preferably removed by washing with water in order to deteriorate blackening resistance and corrosion resistance and promote the occurrence of stains. As a composition used when forming the said base treatment layer, the content ratio of a heavy aluminum phosphate and acidic colloidal silica is 5: 95-35: 65 by mass ratio (aluminum heavy phosphate: colloidal silica), for example. It is preferable that Moreover, it is preferable that 1-10 mass parts of polyacrylic acid is contained with respect to a total of 100 mass parts of aluminum biphosphate and acidic colloidal silica.

  The method for producing the surface-treated metal plate is not particularly limited as long as the surface-treated metal plate according to this embodiment can be produced. Specifically as a manufacturing method of the said surface treatment metal plate, the process (preparation process) of preparing the said surface treatment composition, and apply | coating the said surface treatment composition on the at least one surface of the said zinc-based plated steel plate A manufacturing method comprising a step of performing (coating step) and a step of forming the surface treatment film (drying step) on at least one surface of the galvanized steel sheet by drying the surface treatment composition Is mentioned.

The preparation step is not particularly limited as long as the surface treatment composition can be prepared, and includes, for example, a polyolefin resin emulsified without containing ammonia and colloidal silica having an average particle diameter of 4 to 6 nm. Examples include a step of preparing the surface treatment composition. In this preparation step, the polyolefin resin and the colloidal silica are used so that the content of the colloidal silica is 10 parts by mass or more and less than 30 parts by mass with respect to 100 parts by mass of the surface treatment composition. The process etc. of mixing are mentioned. In addition, this preparation step prepares a surface treatment composition in which the amount of sodium ions eluted from the surface treatment film when immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m ² or less. It is a process to do. Specifically, examples of the colloidal silica include a method using colloidal silica containing ammonia as a dispersant as described above.

The application step is not particularly limited as long as the surface treatment composition can be applied onto at least one surface of the zinc-based plated steel sheet, and examples thereof include application using a bar coater. Moreover, the said application | coating process is a process of apply | coating the said surface treatment composition so that the adhesion amount of the said surface treatment film | membrane may be 0.4-1.2 g / m < ² >.

  The drying step is not particularly limited as long as the surface treatment film can be formed on at least one surface of the galvanized steel sheet by drying the surface treatment composition. Examples of the drying step include drying at 90 to 130 ° C.

  According to such a manufacturing method, the surface-treated metal plate according to the present embodiment can be preferably manufactured.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

  First, each evaluation method used in the following examples will be described.

[Corrosion resistance]
1. Salt spray test (SST flat plate, SST cross cut)
About the test material which gave the back surface and the edge seal | sticker, the thing with a flat cut and what put the crosscut with the cutter knife were produced. Each was sprayed with salt water (5% NaCl aqueous solution) in an atmosphere of 35 ° C. according to JIS Z 2371, and a salt spray test was performed. The time until the occurrence rate of white rust on the test material reached 5 area% was measured.

(SST flat plate)
As an evaluation standard of the SST flat plate, if the time until the white rust occurrence rate for the flat plate reaches 5 area% is 240 hours or more, it is evaluated as “◎”, and it is 168 hours or more and less than 240 hours. If there was, it was evaluated as “◯”, and if it was 120 hours or more and less than 168 hours, it was evaluated as “Δ”, and if it was less than 120 hours, it was evaluated as “x”.

(SST cross cut)
As an evaluation standard for SST crosscuts, if the time until the white rust occurrence rate for crosscuts reaches 5 area% is 120 hours or more, it is evaluated as “◎”, and 96 hours or more and 120 hours When less than, it was evaluated as “◯”, when it was 72 hours or more and less than 96 hours, it was evaluated as “Δ”, and when it was less than 96 hours, it was evaluated as “x”.

2. Salt spray cycle test (SST cycle)
The edge-sealed specimen (flat plate) was subjected to a salt spray cycle test in which salt water (5% NaCl aqueous solution) was sprayed in an atmosphere of 35 ° C. according to JIS Z 2371. In one cycle, salt spray is performed for 8 hours, and then rests for 16 hours. The number of cycles at which the incidence of white rust on the test material reached 5% by area was measured. As an evaluation standard of the SST cycle, if the number of cycles is 10 cycles or more, it is evaluated as “◎”, and if it is 7 cycles or more and less than 10 cycles, it is evaluated as “◯”, and 5 cycles or more and less than 7 cycles. If there was, it was evaluated as “Δ”, and if it was less than 5 cycles, it was evaluated as “x”.

3. Neutral salt spray cycle test (JASO)
About the test material (flat plate) which carried out edge sealing, the neutral salt spray cycle test was implemented according to JISH8502. In one cycle, spraying with salt water is performed for 2 hours, followed by drying (temperature 60 ° C., humidity 30% or more) for 4 hours and wetting (temperature 50 ° C., humidity 95% or more) for 2 hours. The number of cycles at which the incidence of white rust on the test material reached 5% by area was measured. As the evaluation criteria of JASO, if the number of cycles is 21 cycles or more, it is evaluated as “◎”. If it was less than 9 cycles, it was evaluated as “x”.

[Blackening resistance]
The specimen was stored in a constant temperature and humidity tester at a temperature of 50 ° C. and a humidity of 98% or more for 168 hours, and then the color difference (ΔL) before and after the test was measured using a color difference meter. As an evaluation standard for blackening resistance, if ΔL is less than 1, it is evaluated as “◎”, if ΔL is 1 or more and less than 2, it is evaluated as “◯”, and if ΔL is 2 or more and less than 3, When “Δ” was evaluated and ΔL was 3 or more, “×” was evaluated.

[Stain stain resistance]
The specimen was stored in a constant temperature and humidity tester at a temperature of 65 ° C. and a humidity of 95% or more for 168 hours, and then the appearance change before and after the test was visually confirmed. If the occurrence of stains is not confirmed as an evaluation standard for stain resistance, it is evaluated as “◎”. If the occurrence of very slight stains is confirmed, it is evaluated as “○”, and the stains are slightly stained. If it is confirmed that there is a stain, it will be evaluated as “△”. If it is confirmed that stains have occurred on the entire surface, it will be evaluated as “x” and if the surface will be markedly stained. Was evaluated as “XX”.

[Tape resistance]
The adhesion between the surface of the galvanized steel sheet and the surface treatment film under high temperature and high humidity conditions was evaluated. That is, after sticking an adhesive tape (filament tape No. 9510 manufactured by Sliontec Co., Ltd .: rubber adhesive) to the test material and storing it in a constant temperature and humidity test device for 120 hours in an atmosphere of a temperature of 40 ° C. and a humidity of 98%. In accordance with JIS K 5400, a tape peeling test was performed. And the residual rate of the surface treatment film | membrane after implementing a tape peeling test was measured. As an evaluation standard for tape peel resistance, when the residual ratio is 95 area% or more, it is evaluated as “◎”, and when it is 90 area% or more and less than 95 area%, it is evaluated as “◯”, and 80 area. % Or more and less than 90 area% was evaluated as “Δ”, and if it was less than 80 area%, it was evaluated as “x”.

[Coating properties (secondary coating adhesion)]
The specimen was bar-coated with an acrylic paint (Magicron # 1000, manufactured by Kansai Paint Co., Ltd.) so that the coating thickness was 20 μm, and baked at a temperature of 160 ° C. for 20 minutes for post-coating. . Next, after the post-coated test material was immersed in boiling water for 1 hour, taken out and left for 1 hour, the above-mentioned tape peel-off resistance A similar tape peel test was performed. And the number of wrinkles of the coating film which remained without peeling was measured. If the number of remaining wrinkles is 100 as an evaluation standard of paintability (coating film secondary adhesion), it is evaluated as “◎”, and if it is 90 or more and 99 or less, it is evaluated as “◯”. If it was 80 or more and 89 or less, it was evaluated as “Δ”, and if it was 79 or less, it was evaluated as “x”.

[Lubricity (dynamic friction coefficient)]
The dynamic friction coefficient of the test material was measured using a friction coefficient measuring apparatus as shown in FIG. Specifically, as shown in FIG. 5, the test material 51 was sandwiched between flat plate dies 52 and 53, and the flat plate die 53 was pressed toward the test material 51 with a pressure P. In this state, the test material 51 was pulled out between the flat plate die 52 and the flat plate die 53. The pull-out load F at that time was measured, and the dynamic friction coefficient μ (= F / 2P) of each test material was calculated from the measured F. The measurement conditions are as follows. FIG. 5 is a schematic diagram showing a friction coefficient measuring apparatus for evaluating lubricity.

Sample size: 40x300mm
Applied pressure P: 5.4 MPa
Drawing speed: 300 mm / min Flat plate die material: SKD11
As an evaluation standard for oil-free lubrication, when the dynamic friction coefficient μ is less than 0.09, it is evaluated as “◎”, and when it is 0.09 or more and less than 0.15, it is evaluated as “◯”. If it was .15 or more and less than 0.2, it was evaluated as “Δ”, and if it was 0.2 or more, it was evaluated as “x”.

[Test Example 1 (Resin)]
The following resins were used as the resin constituting the surface treatment film.

(Resin A: Polyolefin resin emulsified without ammonia)
In an autoclave having an emulsification facility equipped with a stirrer, a thermometer, and a temperature controller, 626 parts by mass of water and 160 parts by mass of an ethylene-acrylic acid copolymer (acrylic acid unit: 20% by mass, melt index MI: 300). In addition, triethylamine was added at 40 mol% and sodium hydroxide at 15 mol% with respect to 1 mol of the carboxyl group of the ethylene-acrylic acid copolymer. And after performing high-speed stirring at 150 degreeC and 5 Pa, it cooled to 40 degreeC. Here, 4,4′-bis (ethyleneiminocarbonylamino) diphenylmethane (Chemite DZ-22E manufactured by Nippon Shokubai Co., Ltd.) as a cross-linking agent was added to 5 parts by mass of 100 parts by mass of the ethylene-acrylic acid copolymer. Part by mass was added. By doing so, the emulsified ethylene-acrylic acid copolymer (ethylene-unsaturated carboxylic acid copolymer aqueous dispersion) was obtained. This was designated as Resin A. This resin A had an average molecular weight of 60000 and an average particle diameter of 55 nm. Moreover, it was 50 g / m < ² > / day when the water-vapor-permeability was measured by this method using this resin A.

(Resin B: Polyolefin resin emulsified with ammonia)
An ethylene-acrylic acid copolymer (ethylene-unsaturated carboxylic acid copolymer aqueous dispersion) emulsified with ammonia (Hitech S-7024 manufactured by Toho Chemical Industry Co., Ltd.) was used as the resin B. Unlike the case of the resin A, the resin B is produced using emulsified aqueous ammonia during emulsification. This resin B had an average molecular weight of 30,000 and an average particle diameter of 40 nm. Moreover, it was 115 g / m < ² > / day when the water-vapor permeability was measured by this method using this resin B.

(Resin C: A carboxyl group-containing polyurethane resin aqueous dispersion)
In a synthesis apparatus equipped with a stirrer, a thermometer, and a temperature controller, 60 parts by mass of polytetramethylene ether glycol (average molecular weight 1000: manufactured by Hodogaya Chemical Co., Ltd.) as a polyol component, 1,4-cyclohexanedimethanol 14 Part by mass, 20 parts by mass of dimethylolpropionic acid were charged, and 30 parts by mass of N-methylpyrrolidone was added as a reaction solvent. 104 parts by mass of tolylene diisocyanate (TDI) was charged as an isocyanate component, heated to 80 ° C. to 85 ° C., and reacted for 5 hours. The obtained prepolymer had an NCO content of 8.9% by mass. Furthermore, neutralization was performed by adding 16 parts by mass of triethylamine, a mixed aqueous solution of 16 parts by mass of ethylenediamine and 480 parts by mass of water was added, and a chain extension reaction was carried out while emulsifying at 50 ° C. for 4 hours. By doing so, the carboxyl group-containing polyurethane resin aqueous dispersion (polyurethane resin aqueous dispersion) (nonvolatile resin component: 29.1 mass%, acid value: 41.4) was obtained. This was designated as Resin C. Using this resin C, the water vapor transmission rate was measured by the method described above, and it was 1500 g / m ² / day.

(Resin D: Modified epoxy resin aqueous dispersion)
As the resin D, a modified epoxy resin aqueous dispersion (MODEPICS 302 manufactured by Arakawa Chemical Industries, Ltd.) was used.

(Resin E: Polyester resin aqueous dispersion)
As the resin E, an aqueous polyester resin dispersion (Bional MD1200 manufactured by Toyobo Co., Ltd.) was used.

(Surface treatment metal plate No. 1)
In a solid content ratio, 72 parts by mass of resin A and 28 parts by mass of colloidal silica (ST-NXS: ammonia-stabilized type manufactured by Nissan Chemical Industries, Ltd.) having an average particle diameter of 4 to 6 nm are added to the surface treatment composition. Was prepared.

As the metal plate, an electrogalvanized steel plate (zinc adhesion amount 20 g / m ² , plate thickness 0.8 mm) was used. Then, the following base treatment was performed on this metal plate. As the ground treatment, first, the solid content ratio of 50% by mass of an aqueous solution of aluminum phosphate (made by Nippon Chemical Industry Co., Ltd.) and acidic colloidal silica (Snowtex O produced by Nissan Chemical Industries, Ltd.) (Aluminum Biphosphate: Colloidal Silica) is 12:88 and mixed so that the concentration thereof is 1.5% by mass, and polyacrylic acid powder (AC-manufactured by Toa Gosei Co., Ltd.) 10LP) was added to a concentration of 0.1 g / L to prepare a ground treatment solution. This surface treatment liquid was sprayed on the surface of the electrogalvanized steel sheet, which is a metal plate, using a spray ringer apparatus, and then washed with water and dried. By doing so, the metal plate was subjected to a ground treatment, and a ground treatment layer was formed on the metal plate.

A surface treatment in which the surface treatment composition is applied to one side of a metal plate on which a base treatment layer is formed with a bar coater and dried at a plate temperature of 100 ° C. to form a surface treatment film with a film adhesion amount of 0.7 g / m ^2. A steel plate was obtained. As described above, the film adhesion amount was calculated by quantitatively measuring the Si element of colloidal silica (SiO ₂ ) in the film with a fluorescent X-ray analyzer. Further, this surface-treated steel sheet was immersed in deionized water at 70 to 80 ° C. for 10 minutes, and the amount of sodium (Na ⁺ ) eluted was measured by ion chromatography (ICS-5000 + manufactured by Thermo Fisher Scientific Co., Ltd.). As a result, the Na ⁺ elution amount was 2.0 mg / m ² .

(Surface treatment metal plate No. 2-5)
Surface-treated metal plate No. Nos. 2 to 5 are surface-treated metal plates No. 2 except that resins B to E were used instead of resin A, respectively. 1 was produced. The coating amount was also the surface treated metal plate No. As in 1, it was 0.7 g / m ² , and the Na ⁺ elution amount was 2.0 mg / m ² , respectively.

  These surface-treated metal plates No. The results of the above evaluation on 1 to 5 are shown in Table 1 below.

  Moreover, the transition of the white rust generation rate in the evaluation of the SST flat plate and the SST cycle is shown in FIGS. 6 and 7, respectively. In addition, FIG. 6 is a graph which shows a time-dependent change of the white rust generation rate in evaluation of a SST flat plate. In FIG. 6, lines 61 to 65 are respectively surface treated metal plate Nos. The results of 1-5 are shown. FIG. 7 is a graph showing the transition of the white rust occurrence rate with respect to the number of cycles in the evaluation of the SST cycle. In FIG. 7, lines 71 to 75 are respectively surface treated metal plate Nos. The results of 1-5 are shown.

  From these results, when a polyolefin resin emulsified without containing ammonia and colloidal silica having an average particle diameter of 4 to 6 nm (surface-treated metal plate No. 1) is a polyolefin resin. As compared with the case where the resin emulsified containing ammonia is used (surface-treated metal plate No. 2) and the case where other resins are used (surface-treated metal plate No. 3 to 5), It was found to be excellent in blackening, stain stain resistance, and tape peel resistance.

[Test Example 2 (Colloidal Silica)]
As the colloidal silica constituting the surface treatment film, the following products manufactured by Nissan Chemical Industries, Ltd. were used.

ST-NXS, ST-NS, ST-N, and ST-N40 are ammonia-stabilized types, and the average particle diameters are shown in Table 2. Note that the amounts of Na ₂ O contained in ST-NXS, ST-NS, ST-N, and ST-N40 are 300 ppm or less, 400 ppm or less, 400 ppm or less, and 2000 ppm or less, respectively.

ST-XS, ST-S, ST-30, and ST-50 are sodium-stabilized types, and the average particle diameters are shown in Table 2. The amounts of Na ₂ O contained in ST-XS, ST-S, ST-30, and ST-50 are 3000 to 6000 ppm, 6000 ppm or less, 6000 ppm or less, and 6000 ppm or less, respectively.

(Surface treatment metal plate No. 6-13)
In solid content ratio, resin A is 61 parts by mass, colloidal silica shown in Table 2 is 28 parts by mass, glycidyl group-containing cross-linking agent (Epiclon CR5L manufactured by DIC Corporation) is 7.5 parts by mass, lubricant As a result, 3.5 parts by mass of spherical polyethylene wax (Chemipearl W700 manufactured by Mitsui Chemicals, Inc.) was added to prepare a surface treatment composition.

Surface-treated metal plate No. 6-13 are surface treatment metal plate No. except using the said surface treatment composition. 1 was produced. The coating amount was also the surface treated metal plate No. Similar to 1, it was 0.7 g / m ² . The Na ⁺ elution amounts were the values shown in Table 2, respectively.

  These surface-treated metal plates No. The results of the above evaluation on 6 to 13 are shown in Table 2 below.

From Table 2, the average particle diameter is 4 to 6 nm, and the amount of sodium ions (Na ⁺ elution amount) eluted from the surface treatment film when immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m. It was found that the colloidal silica having ² or less is only ST-NXS among the colloidal silicas.

  And when ST-NXS is used (surface-treated metal plate No. 6), compared with the case where the average particle diameter is 8 nm or more (surface-treated metal plate No. 8 to 13), the corrosion resistance, It was found to be excellent in blackening resistance, tape peel resistance, lubricity, and paintability. This is because when colloidal silica is increased, the dispersibility and activity of the colloidal silica in the surface treatment film are lowered, so that the barrier property of the surface treatment film is lowered and the elution amount of colloidal silica in a corrosive environment is lowered. This is probably because of this.

Moreover, when using ST-NXS (surface treatment metal plate No. 6), when using colloidal silica whose Na ⁺ elution amount exceeds 4 mg / m ² (surface treatment metal plates No. 7, 9, 11 and 13), it was found to be excellent in blackening resistance, stain stain resistance and the like. For example, the surface-treated metal plate No. 7 is a surface-treated metal plate No. Although colloidal silica having an average particle diameter of about the same as 6 is used, if the Na ⁺ elution amount exceeds 4 mg / m ² , it is inferior in blackening resistance, stain stain resistance, tape peel resistance, and paintability. I understood.

Next, two kinds of colloidal silica were mixed as follows to adjust the Na ⁺ elution amount from the surface treatment film.

(Surface treatment metal plate No. 14-18)
Surface-treated metal plate No. Nos. 14 to 18 are surface treated metal plate Nos. Except that colloidal silica mixed so as to have a mixing ratio as shown in Table 3 was used. 6 was produced in the same manner. The coating amount was also the surface treated metal plate No. Similar to 6, it was 0.7 g / m ² . The Na ⁺ elution amounts were the values shown in Table 3, respectively.

Table 3 shows the results of adjusting the Na ⁺ elution amount from the surface treatment film by mixing ST-NXS and ST-XS. When ST-NXS was used alone (surface-treated metal plate No. 14), the Na ⁺ elution amount was 2.0 mg / m ² , and good stain resistance was exhibited. Even when the mixing ratio of ST-XS was increased and the Na ⁺ elution amount became 3.9 mg / m ² (surface-treated metal plate No. 17), the surface-treated metal plate No. Similar to 14-16, good stain resistance was exhibited. When ST-XS was used alone (surface-treated metal plate No. 18), the Na ⁺ elution amount was 5.0 mg / m ² , stains were generated, and stain resistance was reduced.

FIG. 8 is a graph showing the relationship between the Na ⁺ elution amount from the surface treatment film and the stain stain. In the stain stain rank in FIG. 8, “5” corresponds to “◎” of the above-mentioned stain stain resistance evaluation criteria, and “4” to “1” are “◯”, “Δ”, “×”, “ Corresponds to “XX”. From FIG. 8, Na ⁺ elution amount is, if 4.0 mg / ^{m 2} or less, but the occurrence of stains stain can be suppressed, Na ⁺ elution amount is more than 4.0 mg / ^{m 2,} stain stain It turns out that generation | occurrence | production of it becomes impossible to suppress.

Further, the surface-treated metal plate No. The tape peel resistance and paintability at 18 were also inferior compared to the other cases. This is presumably because Na ⁺ in the surface treatment film is eluted under conditions of high temperature and high humidity and immersion in boiling water to promote performance deterioration.

Moreover, from Table 3, when Na ^<+> elution amount is 4.0 mg / m < ² > or less (surface treatment metal plate No. 14-17), surface treatment metal plate No.1. Compared with No. 18, as mentioned above, it is not only excellent in stain resistance but also excellent in blackening resistance, tape peel resistance, and paintability.

Furthermore, from Table 3, when Na ^<+> elution amount is 3.7 mg / m < ² > or less (surface treatment metal plate No. 14-16), surface treatment metal plate No.1. Compared to 17, it was found to be excellent in blackening resistance and paintability. From Table 3, when the Na ⁺ elution amount is 3.2 mg / m ² or less (surface-treated metal plates No. 14 and 15), the surface-treated metal plate No. Even when compared with 16, it was found that the tape peel resistance was excellent.

[Test Example 3 (each added amount)]
(Surface treatment metal plate No. 19-25)
Resin A, colloidal silica having an average particle size of 4 to 6 nm (ST-NXS manufactured by Nissan Chemical Industries, Ltd .: ammonia stabilization type), glycidyl group-containing cross-linking agent as a cross-linking agent (Epiclon CR5L manufactured by DIC Corporation), lubrication Spherical polyethylene wax (Chemical Pearl W700 manufactured by Mitsui Chemicals, Inc.) as an agent was added in the composition shown in Table 4 to prepare a surface treatment composition.

Surface-treated metal plate No. Nos. 19 to 25 are surface treatment metal plate Nos. Other than using the surface treatment composition. 1 was produced. The coating amount was also the surface treated metal plate No. Similar to 1, it was 0.7 g / m ² . The Na ⁺ elution amounts were the values shown in Table 4, respectively.

  These surface-treated metal plates No. The results of the above evaluation on 19 to 25 are shown in Table 4 below.

  From Table 4, when the content of the colloidal silica is 10 parts by mass or more and less than 30 parts by mass with respect to 100 parts by mass of the surface treatment composition (surface-treated metal plate No. 19 to 23), this content It was found that the amount was less than 10 parts by mass (surface-treated metal plate No. 24) and was superior in corrosion resistance, blackening resistance, and tape peel resistance. Further, the surface-treated metal plate No. 19 to 23 were found to be excellent in blackening resistance, tape peel resistance, and paintability as compared with the case of 30 parts by mass or more (surface-treated metal plate No. 25). When the content of the colloidal silica is 10 parts by mass or more and less than 30 parts by mass, the colloidal silica is dissolved and eluted in a corrosive environment, and a pH buffering action or a passive film forming action occurs. This is considered to be due to the ability to suitably form a surface-treated film that can sufficiently exert its action.

  Furthermore, from Table 4, when the content of the colloidal silica is 15 parts by mass or more and 28 parts by mass or less with respect to 100 parts by mass of the surface treatment composition (surface treatment metal plate No. 20 to 23), In addition to being excellent in blackening resistance, stain resistance, etc., surface treatment metal plate No. Compared to 19, it was found to be excellent in tape peel resistance and lubricity.

  Moreover, from Table 4, when the content of the colloidal silica is 20 parts by mass or more and 28 parts by mass or less with respect to 100 parts by mass of the surface treatment composition (surface treatment metal plates No. 21 to 23), In addition to being excellent in blackening resistance, stain resistance, etc., surface treatment metal plate No. Even when compared with 19 and 20, it was found that the corrosion resistance was superior.

(Surface treatment metal plate No. 26-31)
Resin A, colloidal silica having an average particle size of 4 to 6 nm (ST-NXS manufactured by Nissan Chemical Industries, Ltd .: ammonia stabilization type), glycidyl group-containing cross-linking agent as a cross-linking agent (Epiclon CR5L manufactured by DIC Corporation), lubrication Spherical polyethylene wax (Chemical Pearl W700 manufactured by Mitsui Chemicals, Inc.) as an agent was added in the composition shown in Table 5 to prepare a surface treatment composition.

Surface-treated metal plate No. Nos. 26 to 31 are surface treatment metal plate Nos. Other than using the above surface treatment composition. 1 was produced. The coating amount was also the surface treated metal plate No. Similar to 1, it was 0.7 g / m ² . The Na ⁺ elution amounts were the values shown in Table 5, respectively.

  These surface-treated metal plates No. The results of the above evaluation for 26 to 31 are shown in Table 5 below.

  From Table 5, when content of the said crosslinking agent is 5-8.5 mass parts with respect to 100 mass parts of said surface treatment compositions (surface treatment metal plate No. 26-29), this content However, compared with the case where it is less than 5 mass parts (surface-treated metal plate No. 30), it turned out that it is excellent in corrosion resistance and blackening resistance. Further, the surface-treated metal plate No. Nos. 26 to 29 were excellent in blackening resistance, stain stain resistance, and the like, and more excellent in paintability than in the case of exceeding 8.5 parts by mass (surface-treated metal plate No. 31). These things are considered to be because a crosslinking reaction can be advanced suitably, suppressing self-crosslinking of an external crosslinking agent as content of the said crosslinking agent is 5-8.5 mass parts. .

  Furthermore, when content of the said crosslinking agent is 6.5-8.5 mass parts with respect to 100 mass parts of said surface treatment compositions (surface treatment metal plate No. 27-29), blackening resistance In addition to being excellent in stain resistance and stain resistance, the surface-treated metal plate No. Compared with No. 26, it was found to be excellent in corrosion resistance, tape peel resistance, and lubricity. This is presumably because the hardness of the surface-treated film increases as the crosslinking reaction proceeds.

(Surface treatment metal plate No. 32-38)
Resin A, colloidal silica having an average particle size of 4 to 6 nm (ST-NXS manufactured by Nissan Chemical Industries, Ltd .: ammonia stabilization type), glycidyl group-containing cross-linking agent as a cross-linking agent (Epiclon CR5L manufactured by DIC Corporation), lubrication Spherical polyethylene wax (Chemical Pearl W700 manufactured by Mitsui Chemicals, Inc.) as an agent was added in the composition shown in Table 6 to prepare a surface treatment composition.

Surface-treated metal plate No. Nos. 32-38 are surface treatment metal plate Nos. Other than using the above surface treatment composition. 1 was produced. The coating amount was also the surface treated metal plate No. Similar to 1, it was 0.7 g / m ² . The Na ⁺ elution amounts were the values shown in Table 6, respectively.

  These surface-treated metal plates No. The results of the above evaluation on 32-38 are shown in Table 6 below.

  From Table 6, when content of the said lubricant is 2-5 mass parts with respect to 100 mass parts of said surface treatment compositions (surface treatment metal plate No. 32-36), this content is As compared with the case of less than 2 parts by mass (surface-treated metal plate No. 37), it was found that the lubricity was excellent. Further, the surface-treated metal plate No. 32 to 36 were found to be excellent in corrosion resistance, blackening resistance, and stain resistance as compared with the case of exceeding 5 parts by mass (surface-treated metal plate No. 38). This is considered to be because the lubricity by the lubricant can be improved while suppressing the deterioration of the corrosion resistance and blackening resistance due to the hydrolysis of the lubricant in a corrosive environment.

  Furthermore, from Table 6, when the content of the lubricant is 2.5 to 5 parts by mass with respect to 100 parts by mass of the surface treatment composition (surface treatment metal plate No. 33 to 36), Not only is it excellent in blackening and stain resistance, but also surface treated metal plate No. Even when compared with 32, it was found to be excellent in lubricity. From this, it was found that the addition amount of the lubricant is more preferably 2.5 parts by mass or more with respect to 100 parts by mass of the surface treatment composition.

  Moreover, from Table 6, when content of the said lubricant is 2-4 mass parts with respect to 100 mass parts of said surface treatment compositions (surface treatment metal plate No. 32-35), blackening resistance In addition to being excellent in stain resistance and stain resistance, the surface-treated metal plate No. Compared to 36, it was found to be excellent in corrosion resistance, tape peel resistance and paintability. From this, it was found that the addition amount of the lubricant is more preferably 4 parts by mass or less with respect to 100 parts by mass of the surface treatment composition.

[Test Example 4 (Amount of coated film)]
(Surface treatment metal plate No. 39-46, 50, and 51)
The solid content ratio is 61 parts by mass of resin A, 28 parts by mass of colloidal silica (ST-NXS: ammonia stabilized type manufactured by Nissan Chemical Industries, Ltd.) having an average particle size of 4 to 6 nm, and contains a glycidyl group as a crosslinking agent. 7.5 parts by mass of a crosslinking agent (Epiclon CR5L manufactured by DIC Corporation) and 3.5 parts by mass of spherical polyethylene wax (Chemical Pearl W700 manufactured by Mitsui Chemicals, Inc.) as a lubricant are added to form a surface treatment composition. Prepared.

Surface-treated metal plate No. Nos. 39 to 46, 50, and 51 are the same as the surface-treated metal plate No. 1 except that the surface treatment composition was used and the coating amount was adjusted to the value shown in Table 7. 1 was produced. The Na ⁺ elution amounts were the values shown in Table 7, respectively.

(Surface treatment metal plate No. 47-49)
Surface-treated metal plate No. 47-49, instead of using ST-NXS manufactured by Nissan Chemical Industries, Ltd. as colloidal silica having an average particle diameter of 4-6 nm, a mixture of ST-NXS and ST-XS manufactured by Nissan Chemical Industries, Ltd. is used. The surface treatment metal plate No. 1 was used except that the surface treatment composition used was adjusted so that the amount of film adhesion was the value shown in Table 7. 1 was produced. The Na + elution amounts were the values shown in Table 7, respectively. Further, the surface-treated metal plate No. 47, the mixing ratio of ST-NXS and ST-XS (ST-NXS: ST-XS) was 2: 1 in terms of mass ratio. Further, the surface-treated metal plate No. 48, the mixing ratio of ST-NXS and ST-XS (ST-NXS: ST-XS) was 1: 1 by mass ratio. Surface-treated metal plate No. In No. 49, the mixing ratio of ST-NXS and ST-XS (ST-NXS: ST-XS) was 1: 2.

  These surface-treated metal plates No. The results of the above evaluation on 39 to 51 are shown in Table 7 below.

From Table 7, the adhesion amount of the surface treatment film, if a 0.4~1.2g / ^{m 2} (surface-treated metal sheet Nanba39～49), the adhesion amount, 0.4 g / ^{m 2} In the case of less than (surface-treated metal plate No. 50), it was found that the corrosion resistance, blackening resistance, tape peel resistance, and lubricity were excellent. Further, the surface-treated metal plate No. It turned out that 39-49 is excellent in the coating property compared with the case where it exceeds 1.2 g / m < ² > (surface treatment metal plate No. 51).

Furthermore, from Table 7, the adhesion amount of the surface treatment film is, if it is 0.45 g / ^{m 2} (surface-treated metal sheet No.40), the amount of adhesion of the surface treatment film is at 0.4 g / ^{m 2} Some surface-treated metal plate No. Compared to 39, it was found to be excellent in blackening resistance, stain stain resistance, tape peel resistance, and lubricity.

Moreover, when the adhesion amount of the said surface treatment film is 0.5 g / m < ² > (surface treatment metal plate No. 41), the surface treatment metal whose adhesion amount of the said surface treatment film is 0.4 g / m < ² > Plate No. Compared with 40, it was found that the corrosion resistance was excellent.

From the above, the adhesion amount of the surface treatment film is preferably at 0.45 g / ^{m 2} or more, it has been found more preferable is 0.5 g / ^{m 2} or more.

Moreover, from Table 7, when the adhesion amount of the surface treatment film is 0.8 g / m ² (surface treatment metal plate No. 44), the adhesion amount of the surface treatment film is 1 g / m ² . Surface-treated metal plate No. Compared to 45, it was found to be excellent in blackening resistance.

Moreover, when the adhesion amount of the said surface treatment film is 0.7 g / m < ² > (surface treatment metal plate No. 43), the surface treatment whose adhesion amount of the said surface treatment film is 0.8 g / m < ² > Metal plate No. Compared to 44, it was found to be excellent in paintability.

From the above, it was found that the adhesion amount of the surface treatment film is preferably 0.8 g / m ² or less, and more preferably 0.7 g / m ² or less.

DESCRIPTION OF SYMBOLS 10 Surface treatment metal plate 11 Surface treatment film 12 Zinc-based plated steel sheet 13 Amorphous oxide 14 Colloidal silica

Claims (7)

A zinc-based plated steel sheet, and a surface treatment film laminated on at least one surface of the zinc-based plated steel sheet,
The surface treatment film is composed of a surface treatment composition containing a polyolefin-based resin not containing ammonia and colloidal silica having an average particle diameter of 4 to 6 nm,
The colloidal silica content is 10 parts by mass or more and less than 30 parts by mass with respect to 100 parts by mass of the surface treatment composition,
The adhesion amount of the surface treatment film is 0.4 to 1.2 g / m ² ,
A surface-treated metal sheet, wherein the amount of sodium ions eluted from the surface-treated film when immersed in deionized water at 70 to 80 ° C. for 10 minutes is 4 mg / m ² or less.   The surface-treated metal sheet according to claim 1, wherein the surface treatment composition further comprises a crosslinking agent and a lubricant.   The surface-treated metal sheet according to claim 2, wherein the content of the cross-linking agent is 5 to 8.5 parts by mass with respect to 100 parts by mass of the surface treatment composition.   The surface-treated metal sheet according to claim 2 or 3, wherein a content of the lubricant is 2 to 5 parts by mass with respect to 100 parts by mass of the surface treatment composition.   The surface-treated metal plate according to any one of claims 1 to 4, wherein the colloidal silica is colloidal silica containing ammonia as a dispersant.   The surface-treated metal sheet according to any one of claims 1 to 5, wherein the polyolefin-based resin contains a copolymer of an α, β-unsaturated carboxylic acid and an olefin. It is a manufacturing method of the surface treatment metal plate which manufactures the surface treatment metal plate of any one of Claims 1-6,
Preparing the surface treatment composition;
Applying the surface treatment composition onto at least one surface of the zinc-based plated steel sheet;
Forming the surface treatment film on at least one surface of the galvanized steel sheet by drying the surface treatment composition.

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