KR20190046950A - Surface-treated metal plate, and method of manufacturing surface-treated metal plate - Google Patents

Abstract

An aspect of the present invention provides a surface treated coating film laminated on the surface of a zinc-based plated steel sheet, wherein the surface treated film comprises 60 to 80 parts by mass of colloidal silica having an average particle diameter of 4 to 6 nm, Treating composition containing 10 to 20 parts by mass of a silane coupling agent based on 100 parts by mass of a total of 20 to 40 parts by mass of a mixed resin of ethylene resin (PU) and ethylene-unsaturated carboxylic acid copolymer resin (EC) Wherein the content ratio of PU and EC is 1: 1 to 9: 1 by mass ratio, the amount of deposition of the surface treated film is 0.4 to 0.8 g / m ² , and when immersed in deionized water at 70 to 80 캜 for 10 minutes, And the amount of Na ⁺ eluted is 4 mg / m ² or less.

Description

Surface-treated metal plate, and method of manufacturing surface-treated metal plate

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

As steel sheets to be applied to household appliances, building materials, automobiles, etc., zinc-based galvanized steel sheets are generally used from the standpoint of corrosion resistance and the like. For the purpose of further improving the corrosion resistance and the like, a surface-treated metal plate on which a surface-treated film is formed on a zinc plated steel sheet has attracted attention. The surface-treated metal sheet is provided with the surface-treated coating on a zinc-plated layer provided on a zinc-based coated steel sheet.

Such a surface-treated metal plate is also required to have excellent conductivity in order to improve antistatic property and electromagnetic shielding property, for example, in the case of being used for electric equipment or the like in conjunction with high performance of electric equipment.

Further, it is known that the surface-treated metal plate is frictionally scratched by friction with corrugated paper or the like during transportation of a truck, called abrasion. Therefore, it is also demanded that the surface-treated metal plate is less prone to occurrence of friction scratches called abrasion.

Further, in the surface-treated metal sheet, severe sliding friction occurs between the surface-treated metal sheet and the metal mold during press forming such as deep drawing. It is known that the surface-treated metal sheet is subject to blackening phenomenon in which the surface-treated film is damaged or the zinc of the zinc-plated layer is mixed into the surface-treated film and is discolored due to this sliding. Thus, the surface-treated metal plate is required to have excellent press formability without causing such a problem.

As a surface-treated metal sheet for the purpose of solving the above-mentioned problems, the present inventor has proposed, for example, a surface-treated metal sheet described in Patent Document 1 or the like. Patent Document 1 discloses a surface treatment comprising a resin film obtained from an aqueous resin solution containing a carboxyl group-containing polyurethane resin, an ethylene-unsaturated carboxylic acid copolymer aqueous dispersion and a resin aqueous solution containing silica particles and a silane coupling agent at a specified ratio A metal plate is described. The surface-treated metal sheet described in Patent Document 1 is excellent in corrosion resistance, durability and conductivity, and is also excellent in paintability and alkali resistance to rust.

In the surface treated metal sheet described in Patent Document 1, the resin coating provided as the surface treated coating contains 55 to 95 parts by mass of silica particles and 5 to 45 parts by mass of the resin component and a large amount of silica particles as inorganic components . This surface-treated metal plate is a surface-treated metal plate having a so-called inorganic film having a relatively large inorganic component. In the surface-treated metal sheet described in Patent Document 1, since the silica particles have a specific gravity of about 2.2, a resin film having a sufficient film adhesion amount is formed even with a comparatively small film thickness. For this reason, the surface-treated metal sheet described in Patent Document 1 has excellent conductivity. Moreover, the surface-treated metal sheet described in Patent Document 1 hardens because it contains a large amount of silica in the resin film, and is excellent in braking resistance and blackening resistance.

On the other hand, it has been well known that zinc-based plated steel sheets which are substrates of the above-mentioned surface-treated metal sheets have conventionally suffered a blackening phenomenon on their surfaces. This blackening phenomenon is a phenomenon in which at least a part of the surface is discolored gently such as black or dark brown. In addition, this blackening phenomenon is concretely a corrosion phenomenon occurring at an early stage in a corrosive environment before white rust is generated, and is said to occur under a relatively mild corrosive environment. In addition, the appearance of the zinc-plated steel sheet due to the blackening phenomenon is glarent when the oxidation reaction (corrosion reaction) of zinc (Zn) present on the surface is carried out in a state of being deviated from the stoichiometric composition of Zn _x O _1-x It is thought that amorphous oxide is generated.

It is also said that the phenomenon of blackening occurs when the oxidation reaction of Zn is in a midst state. To prevent the 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 as an element promoting the oxidation reaction to the zinc plating layer. Examples of such a method include the techniques described in Patent Document 2 and Patent Document 3.

Patent Document 2 discloses that Ni ions are contained in an amount within a 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 (Ni ion / Pb ion ) Is more than 500, electroplating the steel sheet in the electroplating bath and then performing a predetermined chromate treatment.

Patent Document 3 discloses that a Ni ion in a zinc plating bath is contained in an amount of 5 to 500 times the amount of Pb ions contained as an impurity and in an amount of not more than 1/25 of the amount of Zn ions and not more than 10 g / The steel sheet is subjected to electro-galvanization in an electro-galvanizing bath containing zinc oxide and then subjected to a predetermined chromate treatment.

Patent Document 2 and Patent Document 3 disclose that it is possible to suppress the occurrence of a black phenomenon of a zinc plated steel sheet.

In recent years, it has become more demanded that the appearance of the product is excellent. In order to satisfy this requirement, a surface-treated metal plate having a more excellent appearance and further suppressing the occurrence of blackening and stain contamination is required. Thus, the surface-treated metal plate having an inorganic-rich coating as described above is required to further suppress occurrence of blackening or uneven staining.

Japanese Patent Application Laid-Open No. 2006-43913 Japanese Patent Application Laid-Open No. 2-8374 Japanese Patent Laid-Open No. 60-77988

It is an object of the present invention to provide a surface-treated metal plate having an excellent coating film having excellent corrosion resistance, resistance to breakage and conductivity, excellent in weathering resistance and sufficiently suppressing occurrence of stain contamination .

One aspect of the present invention is a method of manufacturing a surface-treated coating film comprising a zinc plated steel sheet and a surface treated coating laminated on at least one surface of the zinc plated steel sheet, wherein the surface treated coating is a colloidal silica 60 having an average particle diameter of 4 to 6 nm And 20 to 40 parts by mass of a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin, wherein the total amount of the colloidal silica and the mixed resin is 100 parts by mass, Wherein the content ratio of the carboxyl group-containing polyurethane resin to the ethylene-unsaturated carboxylic acid copolymer resin is from 1: 1 to 9: 1 by mass, 1, and an adhesion amount of the surface treated film 0.4~0.8g / ² m, the amount of sodium ions eluted from the surface treated film when immersed for 10 minutes in deionized water 70~80 ℃ 4mg / m ² or less is a surface-treated metal sheet.

The above and other objects, features and advantages of the present invention will be apparent from the following detailed description.

1 is a schematic view showing a surface resistance measuring apparatus for evaluating conductivity.
Fig. 2 is a schematic view showing a processing shape in press molding when evaluating press formability. Fig.
Fig. 3 is a schematic view showing a mold shape in press molding when evaluating press formability. Fig.
Fig. 4 is a schematic view showing an evaluation device (a steel sheet stirrup-up device) for evaluating the strength of the steel sheet abrasion resistance.

As described in Patent Documents 2 and 3, a zinc plated steel sheet to which an element such as Ni, Co, and In is added to a zinc plated layer is made of an element such as Ni, Co, and In added to the zinc plated layer , And balance of elements which deteriorate corrosion resistance such as Pb, Cu, and Ag present as impurities in the zinc plated layer must be considered. Further, even if the balance of the zinc-based plated steel sheet is adjusted, occurrence of discoloration unevenness or whiteness is caused by change in the water content of the metal element in the corrosive environment and elution of the metal, etc., . In addition, zinc-based galvanized steel sheets are produced by adding elements such as Ni, Co, and In to the zinc plated layer to excessively accelerate the oxidation reaction, resulting in remarkable decrease in corrosion resistance and generation of white rust or formation of spots (blackish brown or grayish brown) Unevenness (hereinafter referred to as " stain contamination ") is likely to occur.

Therefore, it is required to suppress the occurrence of blackening and uneven staining by a method other than the method of adding an element such as Ni, Co, and In to the zinc plated layer.

When the surface treated film is provided on a zinc plated steel sheet, barrier properties such as oxygen permeability and water vapor permeability may be improved in some cases. In such a case, an oxidation reaction occurs in a state where the supply of oxygen to the surface of the zinc-based plated steel sheet is insufficient, and as described above, the amorphous oxide is generated on the zinc-based plated steel sheet, .

Thus, the inventor of the present invention has found that it is effective to reduce the particle diameter of the colloidal silica to be contained in the surface treated coating, in order to improve the barrier property of the surface treated coating.

In addition, the surface-treated metal sheet provided with the surface-treated coating film on the zinc plated steel sheet may not sufficiently suppress the occurrence of black stain as well as stain staining. The inventor of the present invention has noted that, in the examination leading to the present invention, when colloidal silica is contained in the surface treated film, the occurrence of stain contamination can not be sufficiently suppressed. The surface-treated metal plate having such a surface-treated coating film was allowed to stand in a constant-temperature and constant humidity testing machine set at, for example, a temperature of 65 ° C and a humidity of 95% for 168 hours to cause stain contamination. A ruled line is placed on the surface treated film of the portion where stain contamination of the surface treated metal sheet causing the stain contamination is generated and the surface analysis is performed by using the electron beam microanalyzer (EPMA, JXA-8100 manufactured by Nippon Electronics Co., Ltd.) / Field of view 8 x 8 mm). As a result of this analysis, it was found that the Na element was concentrated in the area where stain contamination occurred. Thus, the present inventor has contemplated that the cause of stain contamination is caused by the presence of Na element. The present inventors further examined the cause of the concentration of the Na element, and the inventor of the present invention paid attention to the colloidal silica contained in the surface-treated coating film, and estimated that the mechanism for causing stain contamination is as follows.

First, in an environment of high temperature and high humidity, a local cell is formed by early erosion on the surface of a zinc plated layer provided with a surface treated film. When general colloidal silica (colloidal silica containing sodium as a dispersant) is contained in the surface treated film, Na element derived from colloidal silica is included in the surface treated film. Then, the Na element derived from the colloidal silica contained in the surface treated coating is concentrated in the cathode portion of the battery, and the initial corrosion is gently promoted, so that the amorphous oxide (amorphous zinc oxide) is formed on the zinc plating layer. Namely, in the surface-treated metal sheet provided with the surface treated film containing colloidal silica on the zinc plated steel sheet, Na ions contained in the colloidal silica migrate to the zinc plated layer surface of the zinc plated steel sheet, . When this amorphous oxide becomes a starting point and corrosion proceeds, the amorphous oxide diffuses into the nonuniformity at the interface between the zinc plated steel sheet and the surface treated film. And the amorphous oxide diffused into the heterogeneous phase appears as a stain-contaminated image. On the basis of such a mechanism, it was presumed that stain contamination occurred in the surface-treated metal plate provided with the surface treatment film containing the colloidal silica as described above. On the other hand, the colloidal silica contained in the surface treated coating was conventionally a colloidal silica containing sodium as a dispersing agent, that is, stabilized with Na ions.

Therefore, the inventors of the present invention thought that when the amount of Na ions to be eluted from the surface treated film is reduced, the amount of amorphous oxide partially formed is reduced, and as a result, stain contamination can be effectively suppressed.

On the basis of the above-described examination, the present inventor has succeeded in the present invention as described below. The object of the present invention is to provide a surface-treated metal plate having an excellent coating film having excellent corrosion resistance, out-braking resistance, and conductivity while exhibiting excellent black weather resistance and sufficiently suppressing occurrence of stain contamination , Which is achieved by the present invention as follows.

A surface-treated metal sheet according to one aspect of the present invention comprises a zinc plated steel sheet and a surface treated coating laminated on at least one surface of the zinc plated steel sheet. The surface-treated film contains 60 to 80 parts by mass of colloidal silica having an average particle size of 4 to 6 nm and 20 to 40 parts by mass of a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin, And 10 to 20 parts by mass of a silane coupling agent based on 100 parts by mass of the total of the colloidal silica and the mixed resin. (PU: EC) of the carboxyl group-containing polyurethane resin (PU) and the ethylene-unsaturated carboxylic acid copolymer resin (EC) contained in the surface treatment composition is 1: 1 to 9: 1. The adhesion amount of the surface treated film is 0.4 to 0.8 g / m ² . In addition, the amount of sodium ions eluted from the surface-treated film, 4mg / m ² or less when immersed for 10 minutes in deionized water 70~80 ℃.

Such a surface-treated metal sheet is excellent in black-black degeneration and can sufficiently suppress the occurrence of stain contamination. In addition, adhesion with the zinc plated layer is also excellent. This is considered to be due to the following.

First, since the average particle size of the colloidal silica contained in such a surface-treated coating film is as small as 4 to 6 nm, the dispersibility and the activity of the colloidal silica are increased, the barrier property of the surface-treated coating is enhanced, I think. It is also considered that the effect of containing the colloidal silica, such as increasing the corrosion resistance, can be suitably exhibited by forming the surface treated film so that the adhesion amount of the surface treated film is 0.4 to 0.8 g / m ² . In addition, the colo parts by weight colloidal silica 60 to 80, when the surface treated film containing the colloidal silica, a relatively large amount, is increased, the density of the surface treatment film, an adhesion amount of the surface treated film 0.4~0.8g / ² m Even so, it becomes relatively thin. Therefore, it is considered that excellent conductivity can be maintained. The content ratio (PU: EC) of the carboxyl group-containing polyurethane resin (PU) and the ethylene-unsaturated carboxylic acid copolymer resin (EC) is 1: 1 to 9: 1 by mass. When such a mixed resin is contained in an amount of 20 to 40 parts by mass, it is considered to be excellent in workability such as corrosion resistance, black marking, press formability, and outbreaking resistance. In such a surface-treated metal plate, a surface-treated film having an amount of sodium ions eluted from the surface-treated film when immersed in deionized water of 70 to 80 ° C for 10 minutes is 4 mg / m ² or less. When the amount of sodium ions eluted from the surface treated coating is small in this manner, it is considered that the occurrence of stain contamination can be suppressed as described above. Thus, the surface-treated metal sheet according to the present embodiment is excellent in corrosion resistance, breaking resistance, conductivity, and the like, and is excellent in black weather resistance and can sufficiently suppress the occurrence of stain contamination.

The zinc plated steel sheet is not particularly limited and may be a zinc-plated steel sheet, or a zinc-based alloy-coated 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-dip plating method, an electroplating method, and an evaporation plating method. Specifically, the galvanized steel sheet may be a galvanized steel sheet (GI), a galvannealed Zn-Fe plated steel sheet (GA), a galvannealed Zn-5% Al coated steel sheet (GF), an electrogalvanized steel sheet (EG) , An electric Zn-Ni alloy plated steel sheet, and the like. Among them, it is preferable to be an electrogalvanized steel sheet (EG).

As described above, the above-mentioned surface treated film is prepared by mixing 60 to 80 parts by mass of colloidal silica having an average particle size of 4 to 6 nm, 20 to 40 parts by mass of a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin And 10 to 20 parts by mass of a silane coupling agent based on 100 parts by mass of the total of the colloidal silica and the mixed resin.

The colloidal silica has an average particle diameter of 4 to 6 nm. Furthermore, based on the above consideration, the colloidal silica is required to have a small amount of sodium ions eluted from the surface treated film. Concretely, the colloidal silica is a colloidal silica having an amount (amount of elution) of sodium ions eluted from the surface-treated film when immersed in deionized water at 70 to 80 캜 for 10 minutes is not more than 4 mg / m ² . The colloidal silica is not particularly limited as long as the colloidal silica is such a colloidal silica.

As the colloidal silica, specifically, it is preferable to include colloidal silica containing ammonia as a dispersing agent. Colloidal silica containing ammonia as such a dispersant, that is, colloidal silica stabilized with NH ₄ ⁺ ions (ammonia stabilization type) is commercially available. By using the colloidal silica containing ammonia as the dispersing agent as described above, as compared with the case where only the colloidal silica (sodium stabilized type) containing sodium is used as the dispersing agent which is the general colloidal silica as described above, The amount of sodium can be reduced. Therefore, a surface treated coating film with reduced elution amount can be obtained.

As described above, the colloidal silica has an average particle size of 4 to 6 nm. If the colloidal silica is too large, the corrosion resistance tends to deteriorate, and further, the workability such as breakage resistance and press formability tends to deteriorate. This is presumably because the dispersibility and the activity of the colloidal silica in the surface treated film are lowered, so that the barrier property of the surface treated film is lowered and the elution amount of the colloidal silica in the corrosive environment is lowered. On the other hand, the smaller the amount of the colloidal silica, the better the corrosion resistance. However, if the colloidal silica is too small, the activity of the surface of the colloidal silica becomes excessively high and the stability of the solution in which the colloidal silica is dispersed tends to decrease. For this reason, the lower limit of the average particle size of the colloidal silica is 4 nm. Thus, by using the colloidal silica having the above-mentioned particle diameter, a surface-treated metal plate excellent in workability such as corrosion resistance, breaking resistance, and press formability can be obtained while maintaining excellent ductility, stain resistance, stain resistance and conductivity . Specific examples of the colloidal silica having an average particle size of 4 to 6 nm include SNOWTEX NXS (ST-NXS, ammonia stabilized type) and SNOWTEX XS (ST-XS, sodium stabilized type) manufactured by Nissan Chemical Industries, . When sodium-stabilized ST-XS is used, it is preferably used in combination with ammonia-stabilized ST-NXS. On the other hand, as the average particle diameter of the colloidal silica herein, for example, when the average particle diameter is about 1 to 10 nm, the Siaz method is used. When the average particle diameter is about 10 to 100 nm, the value measured by the BET method And the like. When the notarized value is described in the pamphlet of the manufacturer, this notarized value is taken as the average particle size of the colloidal silica.

In addition, it is preferable that the amount (amount of elution) of sodium ions to be eluted from the surface-treated film when immersed in deionized water of 70 to 80 ° C for 10 minutes is as small as described above. However, m < ² >, it was found that stain contamination can be suppressed suitably. The elution amount is more preferably 3.8mg / m ² or less, more preferably 3.5mg / m ² or less. Within such a range, it is possible to appropriately suppress black marking and stain resistance. The amount of the elution is preferably as small as possible, but it is limited to about 1 mg / m ² in character of colloidal silica, and the lower limit of the elution amount is preferably 1 mg / m ² or more. On the other hand, the elution amount here is, for example, a value measured as follows. The surface treated metal plate is immersed in deionized water at 70 to 80 占 폚 for 10 minutes. The amount of sodium ions contained in the liquid immersed in the surface-treated metal plate is measured by ion chromatography. The elution amount is calculated from the measured amount of sodium ions and the area of the surface-treated metal plate. On the other hand, as the ion chromatography, for example, ICS-5000 + available from Thermo Fisher Scientific Co., Ltd. can be used.

The mixed resin is a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin. In order to prepare a water-based composition by mixing with colloidal silica, in this embodiment, it is preferable that each of the carboxyl group-containing polyurethane resin and the ethylene-unsaturated carboxylic acid copolymer resin is an emulsion.

The carboxyl group-containing polyurethane resin is not particularly limited as long as it is a polyurethane resin having a carboxyl group in the molecule. Examples of the carboxyl group-containing polyurethane resin include resins obtained by subjecting a urethane prepolymer to chain extension reaction with a chain extender. Examples of the urethane prepolymer include those obtained by reacting a polyisocyanate component and a polyol component, which will be described later, and the like.

The polyisocyanate component constituting the urethane prepolymer includes, for example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), dicyclohexylmethane dianhydride Isocyanate (hydrogenated MDI), tetramethylene diisocyanate, hexamethylene diisocyanate, dodecane methylene diisocyanate, isophorone diisocyanate, xylene diisocyanate , And phenylene diisocyanate. As the polyisocyanate component, among them, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and dicyclohexylmethane diisocyanate (hydrogenated MDI) is preferable. As the polyisocyanate component, the above-exemplified compounds may be used alone, or two or more of them may be used in combination.

Examples of the polyol component constituting the urethane prepolymer include polyol components including all three polyols such as 1,4-cyclohexane dimethanol, polyether polyol and polyol having a carboxyl group, .

The polyether polyol is not particularly limited as long as it has at least two hydroxyl groups in the molecular chain and the main skeleton is composed of alkylene oxide units. Examples of the polyether polyols include polyoxyethylene glycols (polyethylene glycols), polyoxypropylene glycols (polypropylene glycols), polyoxytetramethylene glycols (polytetramethylene glycols) Lactose, polytetramethylene ether glycol), and the like. As the polyether polyol, polyoxypropylene glycol or polytetramethylene ether glycol is preferable. As the polyether polyol, the above-exemplified compounds may be used alone, or two or more of them may be used in combination.

The polyol having a carboxyl group is not particularly limited as long as it has at least one carboxyl group and at least two hydroxyl groups. Examples of the polyol having a carboxyl group include dimethylolpropionic acid, dimethylolbutanoic acid, dihydroxypropionic acid, dihydroxysuccinic acid, and the like. As the polyol having a carboxyl group, dimethylol propionic acid is particularly preferable. As the above-mentioned polyol having a carboxyl group, the above-exemplified compounds may be used alone, or two or more kinds may be used in combination.

The polyol component may also include polyols other than the three kinds of polyols such as 1,4-cyclohexane dimethanol, polyether polyol, and polyol having a carboxyl group.

The chain extender for chain extension reaction of the above-mentioned urethane prepolymer is not particularly limited as long as it is used as a chain extender. Examples of the chain extender include low molecular weight polyols, polyamines, and alkanolamines. Examples of the low molecular weight polyol include the same polyol component as described above. Examples of the polyamines include aliphatic polyamines such as ethylene diamine, propylene diamine, and hexamethylene diamine; Aromatic polyamines such as tolylene diamine, xylylenediamine, and diaminodiphenylmethane; Alicyclic polyamines such as diaminocyclohexyl methane, piperazine and isophoronediamine; And hydrazine such as hydrazine, succinic acid dihydrazide, adipic acid dihydrazide, and phthalic acid dihydrazide. Examples of the alkanolamine include diethanolamine, monoethanolamine, and the like. As the chain extender, ethylenediamine is particularly preferable. As the chain extender, the above exemplified compounds may be used alone, or two or more of them may be used in combination.

The aqueous solution of the carboxyl group-containing polyurethane resin can be produced by a known method. Examples of the production method include a method in which a carboxyl group of a carboxyl group-containing urethane prepolymer is neutralized with a base and subjected to chain extension reaction by emulsification and dispersion in an aqueous medium, and a method in which a carboxyl group-containing polyurethane resin is reacted in the presence of an emulsifier , And a method in which a chain extension reaction is carried out by emulsifying and dispersing in a high shear force.

The ethylene-unsaturated carboxylic acid copolymer resin is a copolymer of ethylene and an ethylenically unsaturated carboxylic acid. And, in the ethylene-unsaturated carboxylic acid copolymer resin here, it is preferable that the constituent unit derived from ethylene is 50 mass% or more in the ethylene-unsaturated carboxylic acid copolymer resin. That is, in the ethylene-unsaturated carboxylic acid copolymer resin, it is preferable that the constitutional unit derived from the ethylenically unsaturated carboxylic acid is 50 mass% or less in the ethylene-unsaturated carboxylic acid copolymer resin.

The ethylene-unsaturated carboxylic acid copolymer resin may be prepared by copolymerizing ethylene and an ethylenically unsaturated carboxylic acid, and copolymerizing ethylene and an ethylenically unsaturated carboxylic acid by a known method. In addition, the ethylene-unsaturated carboxylic acid copolymer resin is commercially available.

The ethylenically unsaturated carboxylic acid is not particularly limited. Examples of the ethylenically 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. As the ethylenically unsaturated carboxylic acid, one type may be used alone, or two or more types may be used in combination. As the ethylenically unsaturated carboxylic acid, among the above-exemplified compounds, acrylic acid and methacrylic acid are preferable, and acrylic acid is more preferable.

The ethylene-unsaturated carboxylic acid copolymer resin may contain an olefin-based monomer such as propylene or 1-butene in place of a part of ethylene. Further, as long as the object of the present invention is not impaired, Some of the monomers may be copolymerized (about 10% by mass or less).

Since the ethylene-unsaturated carboxylic acid copolymer resin has a carboxyl group in the molecule, the ethylene-unsaturated carboxylic acid copolymer resin can be emulsified (water dispersion) by neutralizing with an organic base or a metal ion.

The method of preparing the aqueous dispersion of the ethylene-unsaturated carboxylic acid copolymer is not particularly limited and, for example, an ethylene-unsaturated carboxylic acid copolymer may be added to a homogenizer or the like together with an aqueous medium, The amine and the monovalent metal having a boiling point of 100 占 폚 or less are suitably added in the form of an aqueous solution or the like (firstly, an amine having a boiling point of 100 占 폚 or less is added first, or an amine having a boiling point of 100 占 폚 or less and a compound Are added at about the same time), and a method of stirring with a high shear force.

In the mixed resin, the content ratio (PU: EC) of the carboxyl group-containing polyurethane resin (PU) and the ethylene-unsaturated carboxylic acid copolymer resin (EC) is 1: 1 to 9: 1 , 2: 1 to 9: 1, and more preferably 3.3: 1 to 6.5: 1. If the ratio of EC is too low, the corrosion resistance and black pigmentation tend to decrease. In addition, if the ratio of PU is too low, workability such as press formability tends to decrease. Therefore, when the content ratio is within the above range, a surface-treated metal plate excellent in corrosion resistance, black marking, and workability can be obtained. On the other hand, the content ratio here is a solid content ratio.

The lower limit of the content of the colloidal silica in the total 100 parts by mass of the colloidal silica and the mixed resin is 60 parts by mass or more and preferably 65 parts by mass or more. The upper limit of the content of the colloidal silica is preferably 80 parts by mass or less, and more preferably 75 parts by mass or less. The lower limit of the content of the mixed resin in the total 100 parts by mass of the colloidal silica and the mixed resin is preferably 20 parts by mass or more and more preferably 25 parts by mass or more. The upper limit of the content of the mixed resin is preferably 40 parts by mass or less, and more preferably 35 parts by mass or less. If the colloidal silica is excessively large or excessively large, the corrosion resistance tends to deteriorate. Therefore, it is considered that there is a peak where the content of the colloidal silica is 70 parts by mass and the content of the mixed resin is near 30 parts by mass and the corrosion resistance becomes good. If the amount of the colloidal silica is too small, the density of the surface treated film is lowered, and even if the amount of the surface treated film is the same, the film thickness of the surface treated film becomes thick. In such a case, there is a fear that the conductivity is lowered. In addition, if the amount of the colloidal silica is excessively large, there is a tendency that the stain resistance of the inside stains is lowered. This is presumably because the mixed resin is too small to cause a resin component necessary for forming a film to be insufficient, and cracks and the like in the surface treated film are likely to occur. On the other hand, the content here is a solid content ratio.

The silane coupling agent is a component that improves the adhesion between the metal sheet surface and the surface treated film. The silane coupling agent is not particularly limited. The silane coupling agent includes, for example, a silane coupling agent having a glycidoxy group at the terminal and includes, for example, a silane coupling agent represented by the following formula (1).

[Chemical Formula 1]

In the above formula (1), R1 represents a glycidoxin period, R2 and R3 represent a lower alkoxy group, R4 represents a lower alkoxy group or a lower alkyl group, and X represents a lower alkylene group. Here, the term "lower" means that the number of carbon atoms is 1 to 5, more preferably 1 to 3 carbon atoms.

The lower limit of the content of the silane coupling agent is preferably 10 parts by mass or more, and more preferably 12.5 parts by mass or more based on 100 parts by mass of the total of the colloidal silica and the mixed resin. The upper limit of the content of the silane coupling agent is 20 parts by mass or less based on 100 parts by mass of the total amount of the colloidal silica and the mixed resin. If the amount of the silane coupling agent is too small, there is a tendency that the corrosion resistance, the weathering resistance, the stain resistance, the processability such as press formability, and the braking resistance are lowered. This is considered to be due to the fact that the effect of the silane coupling agent which improves the adhesion between the metal sheet surface and the surface treated film can not be sufficiently exhibited. If the amount of the silane coupling agent is too large, workability such as corrosion resistance, press formability and tear resistance tends to be lowered. It is considered that this is because the liquid stability of the surface treatment composition is lowered and the unreacted silane coupling agent is increased. On the other hand, the content here is a solid content ratio.

The surface-treated film may contain other components in addition to the colloidal silica, the mixed resin, and the silane coupling agent. Other components include, for example, a cross-linking agent for cross-linking the surface treated film, and a lubricant.

The lower limit of the adhesion amount of the surface treatment coating, and 0.4g / m ² or more, preferably not less than 0.5g / m ^2. In addition, the upper limit of the adhesion amount of the surface treated film is, is less than 0.8g / m ^2, more preferably 0.7g / m ² or less. If the adhesion amount of the surface treated film is too small, the barrier property due to the surface treated film is lowered, and the corrosion resistance and the black pigment are lowered, and the spread of the unevenness is promoted. If the amount of the surface-treated coating adhered is too small, workability such as press formability and tear resistance tends to decrease. These tendencies are believed to be attributed to the fact that if the amount of the surface-treated coating adhered is too small, the formed surface-treated coating film becomes too thin, which makes it difficult to coat the coating film on a roll coater or the like, do. In addition, if the amount of the surface-treated coating is excessively large, workability such as conductivity, press formability, and tear resistance tends to be lowered. This is because if the amount of the surface-treated coating adhered excessively, the thickness of the formed surface-treated coating becomes excessively thick, and consequently the conductivity is lowered by the thick coating, furthermore the film residue is generated at the time of press- It is thought that it is easy to occur. On the other hand, the adhesion amount of the surface treated film can be measured, for example, as follows. The Si element of the colloidal silica (SiO ₂ ) in the surface treated film can be quantitatively measured by a fluorescent X-ray analyzer and can be calculated from the measured amount of Si element. On the other hand, the specific gravity of SiO ₂ is 2.2 and the specific gravity of the resin is 1.0.

The surface-treated metal sheet may be provided with the zinc-plated steel sheet and the surface-treated coat, or may have another layer. For example, a ground treatment layer may be provided between the zinc plated steel sheet and the surface treated coating film. Specifically, in order to improve the interfacial adhesion between the surface of the zinc-plated steel sheet and the surface treated film, a reaction type undercoating process comprising a composition of aluminum aluminum, acidic colloidal silica, and polyacrylic acid is performed A base treatment layer may be provided. However, since unreacted phosphoric acid or the like deteriorates the weathering resistance and corrosion resistance and promotes the occurrence of stain contamination, it is preferable to wash and remove.

The method for producing the surface-treated metal sheet is not particularly limited as long as the surface-treated metal sheet according to the present embodiment can be produced. Specifically, the surface-treated metal sheet may be produced by a process (preparation process) of preparing the surface-treating composition, a step (coating process) of applying the surface-treating composition onto at least one surface of the zinc- And a production process comprising drying the surface treatment composition to form the surface treatment film on at least one surface of the zinc plated steel sheet (drying step), and the like.

The preparation process is not particularly limited as long as the surface treatment composition can be prepared. For example, a process for preparing a surface treatment composition comprising the colloidal silica, the mixed resin, and the silane coupling agent . In this preparation step, first, the colloidal silica and the mixed resin are mixed so as to be 60 to 80 parts by mass and 20 to 40 parts by mass with respect to 100 parts by mass of the total of the colloidal silica and the mixed resin, And further mixing the silane coupling agent in an amount of 10 to 20 parts by mass based on the total 100 parts by mass of the colloidal silica and the mixed resin. In addition, the preparation step is a when immersed for 10 minutes in deionized water 70~80 ℃ step for the amount of sodium ions eluted from the surface-treated film, to prepare a surface treatment composition which is 4mg / m ² or less. Specifically, as the colloidal silica, a method using colloidal silica containing ammonia as the dispersant as described above can be given.

The coating step is not particularly limited as long as the surface treatment composition can be coated on at least one surface of the zinc plated steel sheet. For example, application using a bar coater can be mentioned. The coating step is a step of applying the surface treatment composition so that the adhesion amount of the surface treatment coating is 0.4 to 0.8 g / m ² .

The drying step is not particularly limited as long as the surface treated coating can be formed on at least one surface of the zinc plated steel sheet by drying the surface treating composition. Examples of the drying step include drying at 90 to 130 占 폚.

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

Although the present specification discloses various techniques of the present invention as described above, a main technique among them is summarized below.

One aspect of the present invention is a method of manufacturing a surface-treated coating film comprising a zinc plated steel sheet and a surface treated coating laminated on at least one surface of the zinc plated steel sheet, wherein the surface treated coating is a colloidal silica 60 having an average particle diameter of 4 to 6 nm And 20 to 40 parts by mass of a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin, wherein the total amount of the colloidal silica and the mixed resin is 100 parts by mass, Wherein the content ratio of the carboxyl group-containing polyurethane resin to the ethylene-unsaturated carboxylic acid copolymer resin is from 1: 1 to 9: 1 by mass, 1, and an adhesion amount of the surface treated film 0.4~0.8g / ² m, the amount of sodium ions eluted from the surface treated film when immersed for 10 minutes in deionized water 70~80 ℃ 4mg / m ² or less is a surface-treated metal sheet.

According to such a constitution, it is possible to provide a surface-treated metal plate which is excellent in the weathering resistance and in which the occurrence of stain contamination is sufficiently suppressed while maintaining the excellent corrosion resistance, outbreaking resistance and conductivity of the inorganic rich film, And a surface-treated metal sheet excellent in stain resistance.

In the above surface-treated metal plate, it is preferable that the colloidal silica is colloidal silica containing ammonia as a dispersant.

According to such a constitution, a surface-treated metal plate having better black degeneration and stain resistance is obtained.

According to another aspect of the present invention, there is provided a process for producing a surface-treated metal sheet for manufacturing the surface-treated metal sheet, comprising the steps of: preparing the surface-treating composition; And a step of drying the surface treatment composition to form the surface treated coating on at least one surface of the zinc plated steel sheet.

According to such a constitution, it is possible to provide a surface-treated metal plate which is excellent in the weathering resistance and in which the occurrence of stain contamination is sufficiently suppressed while maintaining the excellent corrosion resistance, outbreaking resistance and conductivity of the inorganic rich film, And a surface-treated metal sheet excellent in stain resistance can be produced.

According to the present invention, it is possible to provide a surface-treated metal plate which is excellent in the weathering resistance and in which the occurrence of stain contamination is sufficiently suppressed while maintaining the excellent corrosion resistance, outbreaking resistance and conductivity of the inorganic- A manufacturing method can be provided.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited thereto.

Example

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

[Corrosion resistance]

1. Salt spray test (SST flat plate)

The back side and the edge sealing (flat plate) subjected to the edge sealing were sprayed with a salt water (5% NaCl aqueous solution) in an atmosphere at 35 캜 according to JIS Z 2371, and then subjected to a salt spray test. The time until the incidence of white rust on the disclosure material reached 5 area% was measured.

As the evaluation standard of the SST flat plate, "⊚" is evaluated when the incidence rate of white streaks to the flat plate is equal to or more than 240 hours, and when the incidence rate is equal to or more than 168 hours and less than 240 hours, , And when it was less than 168 hours, it was evaluated as " DELTA ", and when it was less than 120 hours, it was evaluated as "

2. Salt spray cycle test (SST cycle)

A seal water spraying cycle test was conducted in which an edge sealant (flat plate) was sprayed with salt water (5% NaCl aqueous solution) in an atmosphere at 35 ° C in accordance with JIS Z 2371. In one cycle, salt water spraying is carried out for 8 hours, and then the treatment is stopped for 16 hours. And the number of cycles in which the incidence of white rust on the disclosure material reached 5 area% was measured. As the evaluation criteria of the SST cycle, it is evaluated as "? &Quot; when the number of cycles is 10 or more, and evaluated as " , And when it was less than 5 cycles, it was evaluated as " x ".

3. Neutral salt water spray cycle test (JASO)

A neutral salt spray cycle test was conducted on the edge sealing material (flat plate) in accordance with JIS H 8502. The wetting (temperature 50 ° C, humidity 95% or more) is performed for 2 hours in one cycle, followed by spraying with salt water for 2 hours and then drying (temperature 60 ° C, humidity 30% or more) for 4 hours. And the number of cycles in which the incidence of white rust on the disclosure material reached 5 area% was measured. As the evaluation criteria of JASO, it is evaluated as "? &Quot; if the number of cycles is 21 or more, and is evaluated as " , And when it was less than 9 cycles, it was evaluated as " x ".

[Black weathering]

The specimen was stored in a constant temperature and humidity tester at a temperature of 50 캜 and a humidity of 98% or more for 168 hours, and then the color difference (? L) before and after the test was measured using a colorimeter. ? "Is evaluated as"? "When? L is not less than 1 and less than 2, and when? L is not less than 2 and less than 3,? Is evaluated as? If? L was 3 or more, it was evaluated as " x ".

[Contamination of my stain]

The specimens were stored for 168 hours in a constant temperature and humidity tester having a temperature of 65 DEG C and a humidity of 95% or more, and the appearance changes before and after the test were visually confirmed. When the occurrence of stain contamination can not be confirmed as an evaluation standard for the stain stain resistance, it is evaluated as " ", and when it is confirmed that the occurrence of an extremely small stain stain has been confirmed, it is evaluated as "Quot;, and when it is confirmed that the occurrence of stain contamination is observed all over, it is evaluated as " x ", and when it is confirmed that stain stain is remarkably generated on the whole surface, X ".

[Conductivity]

The surface resistance value (conductivity) of a specimen is measured by a surface resistance measuring apparatus 10 as shown in Fig. 1 in which two terminals 12 with a resistor 11 are directly brought into contact with the surface of the specimen 13 did. On the other hand, Fig. 1 is a schematic view showing a surface resistance measuring apparatus for evaluating conductivity. As the surface resistance measuring device 10, LorestaEP of Diamond Instruments Co., Ltd. was used. The measurement was carried out by a 2-probe method using a 2-probe AP probe (type A) (pin interval: 10 mm, pin tip: diameter 2 mm, spring pressure: 240 g / piece, no copper plate). When the measured surface resistance value is less than 0.05?, It is evaluated as "? &Quot;, and when it is less than 0.5?, It is evaluated as " , And when it is 1? Or more, it was evaluated as " x ".

[Press formability (Cylindrical deep drawing test)]

(Single press press) was performed using a 80-ton crank press (NCL-80TS manufactured by AIDA ENGINEERING CO., LTD.). The sealing material was press-molded by using a mold shape as shown in Fig. 3 so as to have a processing shape as shown in Fig. That is, as shown in Fig. 3, the die 33 and the punch 32 press the die 33 to form the die 33 as shown in Fig. On the other hand, Fig. 2 is a schematic view showing a processing shape in press molding when evaluating press formability. 3 is a schematic view showing a mold shape in press molding when evaluating press formability.

The processed shape is as shown in Fig. 2, and the height A is 46 mm and the diameter B is 50 mm. As a press condition, a cylindrical mold for a plate thickness of 0.8 mm was used and press molded at a forming speed of 40 spm, a wrinkle pressing pressure of 1 kgf / cm ² , a drawing ratio of 2.2, and no lubrication (no pressurized oil). The mold shape is as shown in Fig. The die has a blank diameter D of 110 mm in diameter, a punch outer diameter d1 of 50 mm in diameter, a die outer diameter d2 of 51.64 mm in diameter, a radius of curvature R1 of 5 mm in radius of curvature R1 of the die, a radius R2 of 3 mm and a clearance of 20 mm.

As a criterion for evaluation, frictional scratches on the sliding surface of the obtained molded article, mold shrinkage, and blackness were visually evaluated. As a result, it was evaluated as " good " when it was evaluated that friction rubbing of the sliding surface and the generation rate of mold-breaking or blackening phenomenon (part of the coating and plating were peeled off and deposited black) was low and the press formability was extremely good. Quot; was evaluated as " bad ", and " x "

[My steel plate Abre test]

Two sheets of the test specimens were superimposed on each other, and were vibrated using the inner steel plate stirrer apparatus 40 as shown in Fig. 4, and visual evaluation of braking performance was carried out. On the other hand, Fig. 4 is a schematic view showing an evaluation device (a steel sheet abrasion reel device) for evaluating the steel sheet abrasion resistance.

Specifically, in the steel sheet abrasion test, two specimens were cut at a 100 mm angle. Then, a vibration generating device (BF50UC manufactured by Idex Co., Ltd.) was passed through the four corners of the specimen cut at a 100 mm square through the pin 42 provided in the vibration generating device 41 of the steel plate abrading device 40, A hole having a diameter of 6 mm was drilled so as to be installed on the base 41. Was cut into 100 mm square, and a hole with four corners was used for the inner steel sheet abr test. Next, on the vibration generating device 41, a steel plate abrasion jig 43 having a surface 3R semicircular protrusion, two feeds having a length of 100 mm, a cutting surface of 100 mm square, and a hole with four corners Two pieces of ash 44, and a weight of 1 kg. In this state, the vibration generator 41 was vibrated at an amplitude of 5 mm and a frequency of 35 Hz for 5 minutes. The appearance of the test sample after this test was visually confirmed. When it is not possible to confirm the occurrence of the abrasion as an evaluation standard of the inner steel abrasion test, it is evaluated as " ", and when it is confirmed that the occurrence of a slight abrasion has been confirmed, it is evaluated as " When a lot of occurrence of breeding was confirmed, it was evaluated as "? &Quot;, and it was evaluated as " x " when abrasion occurred and metal luster was confirmed.

[Test Example 1: Content of colloidal silica and mixed resin]

As the resin constituting the surface treated film, the following resins were used.

(Carboxyl group-containing polyurethane resin: PU)

60 parts by mass of polytetramethylene ether glycol (average molecular weight 1000: manufactured by Hodogaya Chemical Co., Ltd.) as a polyol component was added to a synthesizer equipped with a stirrer, a thermometer, and a temperature controller, and 1,4-cyclohexane dimethanol And 20 parts by mass of dimethylolpropionic acid were added to the reaction mixture, and 30 parts by mass of N-methylpyrrolidone was further added as a reaction solvent. 104 parts by mass of tolylene diisocyanate (TDI) as an isocyanate component was added, the temperature was raised to 80 to 85 캜, and the reaction was carried out for 5 hours. The NCO content of the obtained prepolymer was 8.9% by mass. Further, 16 parts by mass of triethylamine was added to neutralize, and a mixed aqueous solution of 16 parts by mass of ethylenediamine and 480 parts by mass of water was added, followed by chain extension reaction while being emulsified at 50 ° C for 4 hours. Thus, a polyurethane resin aqueous dispersion (carboxyl group-containing polyurethane resin aqueous dispersion) (nonvolatile resin component 29.1 mass%, acid value 41.4) was obtained. We made this a PU.

(Ethylene-unsaturated carboxylic acid copolymer resin: EC)

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) were added to an autoclave having an emulsification apparatus equipped with a stirrer, a thermometer and a temperature controller, 40 mol% of triethylamine and 15 mol% of sodium hydroxide were added to 1 mol of the carboxyl group of the ethylene-acrylic acid copolymer. Then, the mixture was stirred at 150 ° C and 5 Pa at high speed, and cooled to 40 ° C. To 100 parts of the solid content of the ethylene-acrylic acid copolymer was added 4,4'-bis (ethyleneiminocarbonylamino) diphenylmethane (Chemitate (registered trademark) DZ-22E, manufactured by Nippon Shokubai Co., , And 5 copies. By doing so, an emulsified ethylene-acrylic acid copolymer (ethylene-unsaturated carboxylic acid copolymer aqueous dispersion) was obtained. This is called EC. The water vapor permeability of this resin was 50 g / m ² / day.

Hereinafter, the content of the colloidal silica and the mixed resin was examined.

(Surface-treated metal plate No. 1)

First, the content ratio (PU: EC) of the carboxyl group-containing polyurethane resin (PU) and the ethylene-unsaturated carboxylic acid copolymer resin (EC) To prepare a dispersion.

60 parts by mass of colloidal silica having an average particle size of 4 to 6 nm (ST-NXS: ammonia-stabilized type, manufactured by Nissan Chemical Industries, Ltd.) and 40 parts by mass of a mixed resin of PU: EC = 5: 1 And 15 parts by mass of a silane coupling agent (3-glycidoxypropyltrimethoxysilane, KBM403, Shin-Etsu Chemical Co., Ltd.) was further added to 100 parts by mass of the composition.

As a metal sheet, using the net electric galvanized steel sheet (zinc coating weight 20g / m ^2, thickness 0.8mm), and the surface treatment composition on the one surface, coating adhesion amount 0.6g / m ² so that, in the squeeze rolls with a bar coater Respectively. Then, the metal sheet coated with the surface treatment composition was heated and dried at a temperature of 100 캜. By doing so, a surface-treated metal plate on which a surface-coated film having a coating adhesion amount of 0.6 g / m ² was formed was obtained. The film adhesion amount was calculated by quantitatively measuring the Si element of the colloidal silica (SiO ₂ ) in the film with a fluorescent X-ray analyzer as described above. The surface treated steel sheet was immersed in deionized water at 70 to 80 캜 for 10 minutes and the amount of eluted sodium (Na ⁺ ) was measured by ion chromatography (ICS-5000 + manufactured by Thermo Scientific Co., Ltd.) , And the amount of Na ⁺ eluted was 3.0 mg / m ² .

(Surface-treated metal plates No. 2 to 9)

Surface treated metal plate No. 2 to 9 were the same as the surface treated metal plate No. 1 except that the surface treatment composition prepared so as to have the composition shown in Table 1 was used. 1. The coating adhesion amount was also measured in the surface treated metal plate No. 1. And 0.6 g / m < ² > The amount of Na ⁺ eluted was the value shown in Table 1.

These surface-treated metal plates No. 1 to 9, the results of the above evaluation are shown in Table 1 below.

From Table 1, it can be seen that when the colloidal silica is contained in an amount of 60 to 80 parts by mass and the mixed resin is contained in an amount of 20 to 40 parts by mass (surface-treated metal sheets Nos. 1 to 5) Excellent in corrosion resistance and conductivity as compared with the case where the colloidal silica is contained in an amount of 50 to 55 parts by mass and the mixed resin is contained in an amount of 45 to 50 parts by mass (surface-treated metal plates Nos. 6 and 7) And it was found.

Further, the surface-treated metal plate No. 1 was used. 1 to 5 are excellent in staining resistance to stain and the like. Further, when the colloidal silica is contained in an amount of 85 to 90 parts by mass and the mixed resin is contained in an amount of 10 to 15 parts by mass (surface treated metal plates No. 8 and 9 ), It was found that the corrosion resistance and stain resistance were excellent.

Furthermore, it can be seen from Table 1 that when the content of the colloidal silica is 65 to 75 parts by mass and the content of the mixed resin is 25 to 35 parts by mass (surface-treated metal plates Nos. 2 to 4) Excellent, and the surface treated metal plate No. 1 was excellent. 1, it was found that corrosion resistance, black marking, press formability, and resistance to steel sheet abrasion were excellent.

From Table 1, it can be seen that when the content of the colloidal silica is 65 to 75 parts by mass and the content of the mixed resin is 25 to 35 parts by mass (surface-treated metal plates Nos. 2 to 4). 5, it was found that the corrosion resistance, the black degeneration, and the stain resistance were excellent.

[Test Example 2: PU: EC in mixed resin]

Hereinafter, the content ratio of PU and EC (PU: EC) in the mixed resin was examined.

(Surface-treated metal plates Nos. 10 to 17)

Surface treated metal plate No. 10 to 17 show the results of evaluation of the surface treated metal sheet No. 1 except that the mixed resin shown in Table 2 was used as the content ratio (PU: EC) of PU and EC in the mixed resin. 3. The coating adhesion amount was also measured in the surface treated metal plate No. 1. 3 was 0.6 g / m ² . The amount of Na ⁺ eluted was the value shown in Table 2.

These surface-treated metal plates No. 10 to 17, the results of the above evaluation are shown in Table 2 below.

It can be seen from Table 2 that when the PU: EC has a PU greater than 9: 1 (the surface treated metal sheet No. 10 to 15) when the mixed resin used has a PU: EC of 1: 1 to 9: 16), it was found that corrosion resistance and black degeneration were excellent. Further, the surface-treated metal plate No. 1 was used. 10 to 15 were found to be superior in weathering resistance, press formability and resistance to steel plate abrasion resistance in comparison with the case where the PU was less than 1: 1 (surface treated metal plate No. 17).

It can be seen from Table 2 that when the mixed resin used had a PU: EC ratio of 2: 1 to 6.5: 1 (surface-treated metal sheets Nos. 11 to 14), it exhibited excellent weather resistance, stain resistance, Treated metal plate No. 10, it was found that corrosion resistance and press formability were excellent. From Table 2, it can be seen that when the mixed resin used has a PU: EC of 3.3: 1 to 6.5: 1 (surface-treated metal sheets Nos. 12 to 15). 11, it was found that the steel sheet abrasion resistance was excellent.

From Table 2, it can be seen from Table 2 that when the mixed resin used had a PU: EC of 2: 1 to 6.5: 1 (surface-treated metal sheets Nos. 11 to 14), it exhibited excellent weather resistance, stain resistance, Treated metal plate No. 15, it was found that the corrosion resistance and the steel plate abrasion resistance were excellent. Therefore, it is understood that the content of PU is preferably less than PU: EC of less than 6.5: 1.

Test Example 3 (content of silane coupling agent)

Hereinafter, the content of the silane coupling agent was examined.

(Surface-treated metal plates Nos. 18 to 24)

Surface treated metal plate No. 18 to 24 were the same as the surface treated metal sheet No. 1 except that the content of the silane coupling agent was the content shown in Table 3. 3. The coating adhesion amount was also measured in the surface treated metal plate No. 1. 3, it was 0.6 g / m ² . The amount of Na ⁺ elution was the value shown in Table 3.

These surface-treated metal plates No. 18 to 24, the results of the above evaluation are shown in Table 3 below.

From Table 3 it can be seen that when the content of the silane coupling agent is 10 to 20 parts by mass (surface-treated metal plates No. 18 to 22) relative to 100 parts by mass of the total of the colloidal silica and the mixed resin, Compared with the case where the content of the coupling agent was less than 10 parts by mass (surface-treated metal plate No. 23), it was found that the corrosion resistance, the black degeneration, the stain resistance to the inside, the press formability and the steel sheet abrasion resistance were excellent. Further, the surface-treated metal plate No. 1 was used. 18 to 22 were found to be superior in corrosion resistance, press formability, and resistance to steel sheet abrasion resistance when the content of the silane coupling agent was more than 20 parts by mass (surface-treated metal sheet No. 24).

Furthermore, it can be seen from Table 3 that when the content of the silane coupling agent is 12.5 to 20 parts by mass (surface-treated metal sheets Nos. 19 to 23) relative to 100 parts by mass of the total amount, , And the surface treated metal plate No. 1 was excellent. 18, it was found that corrosion resistance, press formability, and resistance to steel sheet abrasion were excellent.

[Test Example 4 (colloidal silica)]

Hereinafter, colloidal silica was examined.

As the colloidal silica constituting the surface treated coating film, the following ones manufactured by Nissan Chemical Industries, Ltd. were used.

ST-NXS, ST-NS, ST-N and ST-N40 are ammonia-stabilized types, and their average particle diameters are shown in Table 4. On the other hand, the amounts of Na ₂ O contained in ST-NXS, ST-NS, ST-N and ST-N40 are 300ppm or less, 400ppm or less, 400ppm or less or 2000ppm or less, respectively. The amounts of SiO ₂ contained in ST-NXS, ST-NS, ST-N and ST-N40 are 14 to 15 mass%, 20 to 21 mass%, 20 to 21 mass%, 39.5 to 41 mass %to be. The pH values of ST-NXS, ST-NS, ST-N and ST-N40 are all 9-10.

In addition, ST-XS and ST-S are sodium-stabilized type, and the average particle diameters of these are shown in Table 4. On the other hand, the amounts of Na ₂ O contained in ST-XS and ST-S are 3000 to 6000 ppm and 6000 ppm or less, respectively. The amounts of SiO ₂ contained in ST-XS and ST-S are 20 to 21 mass% and 30 to 31 mass%, respectively. The pH of ST-XS is 9 to 10, and the pH of ST-S is 9.5 to 10.5.

(Surface-treated metal sheets No. 25 to 30)

70 parts by mass of colloidal silica shown in Table 4 and 30 parts by mass of a mixed resin of PU: EC = 5: 1 were mixed with 100 parts by mass of a silane coupling agent (3-glycidyl (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.) was added in an amount of 15 parts by mass to prepare a surface-treating composition.

Surface treated metal plate No. 25 to 30 are examples of the surface-treated metal sheet No. 1 except for the use of the surface-treating composition. 3. The coating adhesion amount was also measured in the surface treated metal plate No. 1. 3, it was 0.6 g / m ² . The amounts of Na ⁺ eluted were values shown in Table 4, respectively.

These surface-treated metal plates No. 25 to 30, the results of the above evaluation are shown in Table 4 below.

From Table 4, the average particle size of 4~6nm, when immersed for 10 minutes in deionized water 70~80 ℃ amount of sodium ions eluted from the surface treated film (Na ⁺ elution) a colloidal that 4mg / m ² or less The silica was found to be only ST-NXS in the colloidal silica.

When ST-NXS was used (surface-treated metal plate No. 25), corrosion resistance, press formability, and internal resistance were improved in comparison with the case where the average particle diameter was 8 nm or more It was found that the steel plate abrasion resistance was excellent.

In addition, when ST-NXS was used (surface-treated metal plate No. 25), compared with the case where colloidal silica having a Na ⁺ elution amount exceeding 4 mg / m ² was used (surface treated metal plates No. 28 to No. 30) , And black stain and stain resistance. For example, the surface-treated metal plate No. 1 can be used. 30 denotes a surface-treated metal plate No. 1; Although colloidal silica having an average particle size of about 25 was used, when the amount of Na ⁺ elution exceeded 4 mg / m ² , it was found that the weathering resistance and the stain resistance to in-stain were inferior.

Also, if the colloidal silica is too large, the surface treated metal plate No. 1 can be obtained. As shown in Fig. 28, it was also found that the conductivity was lowered.

[Test Example 5 (Coating amount of film)]

(Surface-treated metal plates No. 31 to 37)

70 parts by mass of colloidal silica having an average particle size of 4 to 6 nm (ST-NXS: ammonia stabilized type, manufactured by Nissan Chemical Industries, Ltd.) and 30 parts by mass of a mixed resin having PU: EC = 5: 15 parts by mass of a silane coupling agent (3-glycidoxypropyltrimethoxysilane, KBM403, Shin-Etsu Chemical Co., Ltd.) was further added to 100 parts by mass of the composition to prepare a surface-treating composition.

Surface treated metal plate No. 31 to 37 were prepared in the same manner as in the surface-treated metal sheet No. 1 except that the above-mentioned surface treatment composition was used to adjust the coating adhesion amount to the values shown in Table 5. 3. The amounts of Na ⁺ eluted were the values shown in Table 5, respectively.

These surface-treated metal plates No. The results of the above evaluations are shown in Table 5 below.

It can be seen from Table 5 that when the adhesion amount of the surface treated film is 0.4 to 0.8 g / m ² (surface treated metal plates No. 31 to 35), the adhesion amount is less than 0.4 g / m ² (surface treated metal plate No. 36 , It was found that corrosion resistance, black degeneration, stain resistance to in-stain, press formability and resistance to steel sheet abrasion were superior. Further, the surface-treated metal plate No. 1 was used. 31 to 35 were found to be superior in conductivity, press formability, and resistance to steel sheet abrasion in comparison with the case of exceeding 0.8 g / m ² (surface-treated metal plate No. 37).

Furthermore, from Table 5, the adhesion amount of the surface treated film, 0.5~0.7g / m in ² cases (surface-treated metal sheet No. 32~34), the adhesion amount is 0.4g / m ² of a surface-treated metal sheet No. Compared with No. 31, it was found that corrosion resistance, press formability and resistance to steel sheet abrasion were excellent. Thus, it is understood that the adhesion amount of the surface treated film is preferably 0.5 g / m ² or more.

It can be seen from Table 5 that the surface-treated metal sheet No. 1 having the adhesion amount of 0.8 g / m ² when the adhesion amount of the surface-treated coat is 0.5 to 0.7 g / m ² (surface-treated metal sheets No. ³² to 34). 35, it was found that it was excellent in conductivity and press formability. Thus, it is understood that the adhesion amount of the surface treated film is preferably 0.7 g / m ² or less.

This application is based on Japanese Patent Application No. 2016-178480 filed on September 13, 2016, the contents of which are incorporated herein.

In order to express the present invention, the present invention has been appropriately and fully described in the foregoing for the embodiments of the present invention. However, it should be understood by those skilled in the art that modifications and / or improvements of the above-described embodiments can be made easily. It is therefore intended that such changes or modifications be construed to be within the scope of the appended claims unless the modifications or modalities to those skilled in the art are to fall within the scope of the claims of the claims .

According to the present invention, it is possible to provide a surface-treated metal plate which is excellent in the weathering resistance and in which the occurrence of stain contamination is sufficiently suppressed while maintaining the excellent corrosion resistance, outbreaking resistance and conductivity of the inorganic- A manufacturing method can be provided.

Claims (3)

A zinc plated steel sheet; and a surface treated film laminated on at least one surface of the zinc plated steel sheet,
The surface-treated film contains 60 to 80 parts by mass of colloidal silica having an average particle diameter of 4 to 6 nm and 20 to 40 parts by mass of a mixed resin of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer resin, A surface treating composition comprising 10 to 20 parts by mass of a silane coupling agent based on 100 parts by mass of the total of the colloidal silica and the mixed resin,
Wherein the content ratio of the carboxyl group-containing polyurethane resin to the ethylene-unsaturated carboxylic acid copolymer resin is 1: 1 to 9: 1 in mass ratio,
The adhesion amount of the surface treated film is 0.4 to 0.8 g / m ² ,
When immersed for 10 minutes in deionized water 70~80 ℃ surface-treated metal sheet according to the amount of sodium ions wherein 4mg / m ² or less is eluted from the surface treated film. The method according to claim 1,
Wherein the colloidal silica is colloidal silica containing ammonia as a dispersant. A method of producing a surface-treated metal sheet for producing the surface-treated metal sheet according to claim 1 or 2,
A step of preparing the surface treatment composition,
Applying the surface treatment composition onto at least one surface of the zinc plated steel sheet;
And a step of drying the surface treatment composition to form the surface treated coating on at least one surface of the zinc plated steel sheet.

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