TW201631176A - Steel sheet for container and method of manufacturing the same - Google Patents

Abstract

A steel sheet for a container includes a steel sheet, a composite plating layer which contains Ni of 2.0 to 200 mg/m2 in terms of Ni metal and Sn of 0.10 to 10.0 g/m2 in terms of Sn metal as an upper layer of the steel sheet, a metal Ni-plated layer which contains 1.0 to 2000 mg/m2 in terms of Ni metal as an upper layer of the composite plating layer, and a chemical conversion coating layer which contains a Zr compound of 0.01 to 150 mg/m2 in terms of Zr metal and a phosphoric acid compound of 0.01 to 80 mg/m2 in terms of P as an upper layer of the metal Ni-plated layer.

Description

Steel sheet for container and method for producing steel sheet for container Field of invention

The present invention relates to a method for producing a steel sheet for a container and a steel sheet for a container.

The present application claims priority based on Japanese Patent Application No. 2015-3597, filed on Jan. 9, 2015, to Japan, and its content is hereby incorporated herein.

Background of the invention

As a container for beverages or foods, a metal container in which a Sn-plated steel sheet or a Sn-based alloy-plated steel sheet is used for canning is often used. In the case of the metal container, the surface of the metal container must be applied before or after the can making. However, in recent years, in order to reduce wastes such as waste materials such as waste solvents and carbon dioxide and the like from the viewpoint of global environmental protection, a laminated film is often used instead of coating. Moreover, the steel plate used for the metal container is called "steel plate for containers".

In the steel sheet for containers used for the coating or the film (hereinafter referred to as "coating agent"), in order to ensure adhesion to the coating agent and corrosion resistance, hexavalent chromate or the like is often used. The anti-rust treatment of chromate (hereinafter referred to as "chromate treatment") (for example, refer to Patent Document 1 below).

However, recently, since hexavalent chromium used for chromate treatment is environmentally harmful, it has been conventionally reviewed that chromate treatment applied to steel sheets for containers is replaced with other surface treatments. That is, a surface treatment applied to the surface of a steel sheet for a container which is excellent in adhesion to a coating agent and corrosion resistance is sought. For example, in the following Patent Document 2, a chemical conversion treatment using a chemical conversion treatment bath containing Zr and phosphoric acid is disclosed as a surface treatment instead of chromate treatment.

Advanced technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2000-239855

Patent Document 2: Japanese Laid-Open Patent Publication No. 2007-284789

Summary of invention

As a material for a metal container which is required to have corrosion resistance as a three-piece can for storing an acidic beverage, it has been conventionally used to form a composite plating layer having an island-shaped Sn layer on an Fe-Ni-Sn alloy layer. The chromate treated steel plate was applied. However, according to the results of the review by the inventors of the present invention, the following matters have become clear: the chemical conversion treatment using the chemical conversion treatment bath containing Zr and phosphoric acid disclosed in the above Patent Document 2 is used instead of the chromate treatment. When a film is deposited on the film layer formed by the chemical conversion treatment (hereinafter referred to as "chemical conversion treatment film layer"), the adhesion between the steel sheet for the container and the film is lowered.

The present invention has been made in view of the foregoing circumstances, and aims to provide A method for producing a steel sheet for a container and a steel sheet for a container having excellent film adhesion.

The inventors of the present invention have conducted a review on the adhesion of the chemical conversion treatment film layer to the film laminated on the chemical conversion treatment film layer. As a result, it was found that an Sn-containing oxide layer containing Sn was formed at the interface between the chemical conversion treatment film layer and the composite plating layer due to oxygen permeation into the inside of the chemical conversion treatment film layer. Further, the inventors of the present invention have found that since the Sn oxide layer is weak, once the Sn oxide layer is formed thick, it is peeled off together with the Sn oxide layer, and there is a possibility that the film adhesion property is deteriorated.

In order to solve the above problems and achieve the object, the present invention employs the following means.

(1) A steel sheet for a container according to one aspect of the present invention, comprising: a steel sheet; and a composite plating layer, which is an upper layer of the steel sheet, and contains Ni in an amount of 2.0 to 200 mg/m ^{2 in terms} of metal Ni The amount of metal Sn is 0.10 to 10.0 g/m ² of Sn, and an island-shaped Sn layer is formed on the Fe-Ni-Sn alloy layer; the metal Ni plating layer is used as the upper layer of the composite plating layer, and Ni containing 1.0 to 2000 mg/m ^{2 in terms} of the amount of metal Ni; and a chemical conversion coating layer as the upper layer of the metal Ni plating layer, and containing 0.010 to 150 mg/m ^{2 in} terms of the amount of metal Zr. The Zr compound is a phosphate compound in an amount of 0.010 to 80 mg/m ^{2 in terms} of P.

(2) The steel sheet for a container according to the above item (1), wherein the composite plating layer may have a configuration in which Ni is contained in an amount of 5.0 to 150 mg/m ^{2 in terms} of the amount of metal Ni, and the amount of metal Sn is converted. It is calculated as Sn of 0.5 to 7.0 g/m ² .

(3) The steel sheet for a container according to the above (1) or (2), wherein the metal Ni plating layer may have a composition containing Ni in an amount of 5.0 to 1500 mg/m ^{2 in terms} of the amount of metal Ni.

(4) The steel sheet for a container according to any one of the items (1) to (3) above, wherein the chemical conversion treatment film layer may have a constitution in which the content of the metal-containing Zr is 0.050 to 120 mg/inclusive. The aforementioned Zr compound of m ² .

(5) The steel sheet for a container according to any one of the items (1) to (4) above, wherein the chemical conversion treatment film layer may have a constitution in which the content is 0.05 to 60 mg/m in terms of P. ² phosphoric acid compounds.

(6) The steel sheet for a container according to any one of the above items (1) to (5), wherein a Sn oxide layer is further used between the composite plating layer and the metal Ni plating layer. And the Sn oxide layer contains oxidized Sn having a power amount required for reduction of 3.0 mC/cm ² or less.

(7) A method for producing a steel sheet for a container according to an aspect of the present invention, comprising the step of forming a first Ni plating layer on a steel sheet to form a content of 0.1% in terms of a metal to be converted into a metal. a first Ni plating layer of 200 mg/m ² of Ni; a Sn plating layer forming step of forming a Sn containing 0.10 to 10 g/m ^{2 in terms} of a metal Sn amount on the first Ni plating layer a Sn plating layer; a molten tin treatment step of forming a composite plating layer having an island-like Sn layer on the Fe-Ni-Sn alloy layer by performing a molten tin treatment; and a second Ni plating layer forming step After the molten tin treatment step, a second Ni plating layer is formed on the composite plating layer by using a Ni plating bath containing 10 g/L or more of sulfate ions and 30 g/L or more of Ni ions; And a chemical conversion treatment film formation step, after the second Ni plating layer formation step, using the following chemical conversion treatment bath, and performing a current density of 0.5 to 20 A/dm ² and 0.05 to 10 seconds Cathodic electrolysis treatment of the cathode electrolysis treatment time of the clock, or the immersion treatment time of 0.2 to 100 seconds The immersion treatment forms a chemical conversion treatment film layer on the second Ni plating layer; the chemical conversion treatment bath contains 10 to 20000 ppm of Zr ions, 10 to 20000 ppm of F ions, 10 to 3000 ppm of phosphate ions, and a total of 100 ~30000ppm of nitrate and sulfate ions, and the temperature is 5~90 °C.

According to the above aspects, it is possible to provide a steel sheet for a container having excellent film adhesion and a method for producing a steel sheet for a container.

10‧‧‧Steel plates for containers

101‧‧‧ plated steel plate

103‧‧‧ steel plate

105‧‧‧Composite plating

105a‧‧‧Fe-Ni-Sn alloy layer

105b‧‧‧ island-like Sn layer

107‧‧‧Second Ni plating layer (metal Ni plating layer)

109‧‧‧Chemical conversion treatment of the film layer

121‧‧‧Sn oxide layer

151‧‧‧covered layer

153‧‧‧Ni-Sn alloy layer

160‧‧‧PET film

S101, S103, S105, S107, S109, S111, S113‧‧

Fig. 1A is an explanatory view showing a layer structure of a steel sheet for a container according to the embodiment.

Fig. 1B is an explanatory view showing a layer structure of a steel sheet for a container according to the embodiment.

Fig. 2 is an explanatory view showing a configuration of a composite plating layer of a steel sheet for a container according to the present embodiment.

Fig. 3 is an explanatory view showing the formation of a Sn oxide layer when a conventional technique is used.

4A is an explanatory view for explaining a method of measuring the amount of formation of Sn oxide.

4B is a view for explaining a method of measuring the amount of formation of Sn oxide. Figure.

Fig. 5 is an explanatory view showing a case where a coating agent is applied to the surface of the steel sheet for a container according to the embodiment.

Fig. 6 is an explanatory view for explaining a method of measuring the amount of Ni attached.

Fig. 7 is a flow chart showing an example of the flow of a method for producing a steel sheet for a container according to the present embodiment.

Figure 8 is an explanatory diagram for explaining an embodiment.

Form for implementing the invention

Hereinafter, the method for producing a steel sheet for a container and a steel sheet for a container according to the embodiment will be described in detail with reference to the additional drawings. In the present embodiment, constituent elements that have substantially the same functional configuration are denoted by the same reference numerals and will not be described.

<Construction of steel plate 10 for containers>

Hereinafter, the configuration of the steel sheet 10 for a container according to the present embodiment will be described in detail with reference to FIGS. 1A to 5 .

1A and 1B are explanatory views showing a layer structure when the steel sheet 10 for a container according to the present embodiment is viewed from the side. Fig. 2 is an explanatory view showing a configuration of a composite plating layer of the steel sheet 10 for a container according to the embodiment. Fig. 3 is an explanatory view for explaining the formation of a Sn oxide layer when a conventional technique is used. 4A and 4B are explanatory views for explaining a method of measuring the amount of formation of Sn oxide. Fig. 5 is an explanatory view showing a case where a coating agent is applied to the surface of the steel sheet 10 for a container according to the embodiment. Fig. 6 is an explanatory view for explaining a method of measuring the amount of Ni attached.

The steel sheet 10 for a container according to the present embodiment has a plated steel sheet 101 and a chemical conversion treated film layer 109 as shown in Figs. 1A and 1B. Here, the plated steel sheet 101 has a steel sheet 103 as a base material, a composite plating layer 105 formed on the steel sheet 103, and a second Ni plating layer (metal Ni plating) formed on the composite plating layer 105. Layer) 107. Further, the composite plating layer 105, the second Ni plating layer (metal Ni plating layer) 107, and the chemical conversion treatment film layer 109 may be formed only on one surface of the steel sheet 103 as shown in FIG. 1A. Alternatively, as shown in Fig. 1B, the steel sheets 103 may be formed on opposite surfaces of each other.

Further, the composite plating layer 105 is connected to the surface of the steel sheet 103, the second Ni plating layer (metal Ni plating layer) 107 is connected to the surface of the composite plating layer 105, and the chemical conversion treatment film layer 109 is bonded to the metal. The surface of the Ni plating layer (second Ni plating layer) 107 is connected.

Further, in the present embodiment, the Ni plating layer formed on the steel sheet 103 to form the composite plating layer 105 is referred to as a "first Ni plating layer" (not shown), and is formed on the composite plating layer. The Ni plating layer on the cladding layer 105 is referred to as "second Ni plating layer (metal Ni plating layer) 107".

[About steel plate 103]

The steel sheet 103 is used as a base material of the steel sheet 10 for a container according to the present embodiment. The steel plate 103 used in the present embodiment is not particularly limited, and a known steel plate 103 which is generally used as a container material can be used. The manufacturing methods and materials of these well-known steel sheets are also not particularly limited. It can be manufactured by the usual steel sheet manufacturing steps, such as hot rolling, pickling, cold rolling, annealing and quenching and tempering. Steel plate 103.

[About composite plating layer 105]

A barrier plating type composite plating layer 105 containing at least Sn is formed on the surface of the steel sheet 103 as an upper layer of the steel sheet 103. Here, the "barrier type plating layer" is a metal which is more precious than the electrochemically more precious Fe of the steel sheet 103 constituting the base material, and the metal film of Sn is formed on the surface of the steel sheet 103 so that the corrosion factor is not A plating layer that acts on the base material and suppresses corrosion of the steel sheet 103.

Hereinafter, an example of the composite plating layer 105 according to the present embodiment will be specifically described with reference to Fig. 2 . In addition, in FIG. 2, the case where the composite plating layer 105, the second Ni plating layer 107, and the chemical conversion processing film layer 109 are formed only on one surface of the steel plate 103 is illustrated.

The composite plating layer 105 is formed on at least one side of the steel sheet 103. The composite plating layer 105 is composed of an Fe-Ni-Sn alloy layer 105a and an island-shaped Sn layer 105b formed on the Fe-Ni-Sn alloy layer 105a. The Fe-Ni-Sn alloy layer 105a and the island-shaped Sn layer 105b are formed by forming a first Ni plating layer (not shown) to be a base on the surface of the steel sheet 103, and Further, after the Sn plating layer (not shown) is formed on the first Ni plating layer (not shown), molten tin treatment (reflow processing) is performed. That is, the Fe-Ni alloy is formed by alloying the Fe of the steel sheet 103 with the Ni of the first Ni plating layer (not shown) and Sn of a part of the Sn plating layer (not shown) to form an Fe-Ni-Sn alloy. The layer 105a, and at the same time, a residual Sn plating layer (not shown) becomes an island shape, and an island-shaped Sn layer 105b is formed.

The first Ni plating layer (not shown) is made of Ni or Fe-Ni alloy The formation is formed to ensure corrosion resistance. Since Ni has excellent corrosion resistance, the corrosion resistance of the composite plating layer 105 can be improved by forming a first Ni plating layer (not shown) on the surface of the steel sheet 103.

The corrosion-improving effect by Ni depends on the amount of Ni plated. When the amount of Ni in the composite plating layer 105 is 2.0 mg/m ² or more in terms of the amount of metal Ni, the effect of improving the corrosion resistance is exhibited. On the other hand, although the amount of Ni in the first Ni plating layer is increased, the corrosion improving effect is enhanced. However, once the amount of Ni in the composite plating layer 105 is converted into a metal Ni amount exceeding 200 mg/m ² , corrosion resistance is obtained. The lifting effect will be saturated. In addition, when the amount of Ni in the composite plating layer 105 is more than 200 mg/m ² in terms of the amount of metal Ni, since Ni is a high-priced metal, it is not economically preferable. Therefore, the amount of Ni in the composite plating layer 105 is 2.0 to 200 mg/m ^{2 in} terms of the amount of metal Ni.

The content of Ni in the composite plating layer 105 is preferably 5.0 to 150 mg/m ^{2 in} terms of the amount of metal Ni. When the composite plating layer 105 contains Ni in an amount of 5.0 mg/m ² or more in terms of metal Ni, the above effects can be more reliably achieved. In addition, when the composite plating layer 105 contains Ni in an amount of 150 mg/m ² or less in terms of metal Ni, the manufacturing cost can be further reduced.

On the first Ni plating layer described above, a Sn plating layer (not shown) is formed. In addition, the "Sn plating" in the present embodiment does not mean that it is composed only of the metal Sn, and may contain impurities in addition to the metal Sn, and may contain a trace element in addition to the metal Sn.

The Sn plating layer (not shown) is formed to ensure corrosion resistance and weldability of the steel sheet 10 for a container. Since Sn has high corrosion resistance itself, even if it is used as the metal Sn, it is shaped by the treatment of molten tin as described below. The alloy Sn can also exhibit excellent corrosion resistance and weldability.

When the coating agent is applied to the surface of the steel sheet 10 for a container and the coating material is subjected to heat treatment, the steel sheet 10 for a container may be heated to a melting point (232 ° C) or higher of Sn. Therefore, when the entire surface of the first Ni plating layer (not shown) is covered with Sn, the coating agent cannot be properly adhered due to the melting of Sn or the oxidation of Sn.

On the other hand, in the composite plating layer 105 of the present embodiment, the island-shaped Sn layer 105b is formed on the Fe-Ni-Sn alloy layer 105a. By this means, even when the steel sheet 10 for a container is heated to a temperature equal to or higher than the melting point of Sn, the Fe-Ni-Sn alloy layer in the Fe-Ni-Sn alloy layer 105a corresponding to the sea portion is not melted. By this, the appropriate adhesion of the steel sheet 10 for a container to the coating material can be obtained.

Sn has excellent processability, weldability, and corrosion resistance. However, by performing tin-plating treatment after Sn plating, corrosion resistance can be further improved, and the surface appearance (mirror appearance) can be made appropriate.

In order to make the above effect appear, the Sn content of the entire composite plating layer 105 is required to be 0.10 g/m ² or more in terms of the amount of metal Sn. Further, although the Sn content is increased, the corrosion resistance is increased. However, when the amount of the metal Sn is more than 10 g/m ² , the corrosion resistance improving effect tends to be saturated. Therefore, from the viewpoint of economy, the Sn content of the entire composite plating layer 105 is set to 10 g/m ² or less in terms of the amount of metal Sn.

The content of Sn in the entire composite plating layer 105 is preferably 0.5 to 7.0 g/m ^{2 in} terms of the amount of metal Sn. The above effect can be more reliably exhibited by containing Sn in an amount of 0.5 g/m ² or more in terms of the amount of metal Sn. In addition, by setting the Sn content of the entire composite plating layer 105 to 7.0 g/m ² or less in terms of the amount of metal Sn, the manufacturing cost of the composite plating layer 105 can be further reduced.

[About the second Ni plating layer 107]

On the surface of the composite plating layer 105, as shown schematically in FIG. 1A and FIG. 1B, a second Ni plating layer 107 mainly composed of Ni is formed. The second Ni plating layer 107 is formed to cover the composite plating layer 105 along the surface shape of the composite plating layer 105. Therefore, the surface shape of the formed second Ni plating layer 107 reflects the surface shape of the composite plating layer 105.

As shown in FIG. 3, when the second Ni plating layer 107 is not disposed on the composite plating layer 105, oxygen present in the atmosphere may penetrate into the chemical conversion treatment film layer 109 in a layer of several hours, and oxygen will be present. The interface between the composite plating layer 105 and the chemical conversion treatment film layer 109 is reached. As a result, oxygen reacts with Sn in the composite plating layer 105, and the Sn oxide layer 121 composed of oxidized Sn (SnOx) is formed in the interface between the composite plating layer 105 and the chemical conversion coating layer 109. . Since the Sn oxide layer 121 is weak, once the Sn oxide layer 121 is formed thick, it is peeled off along with the Sn oxide layer 121, so that the film adhesion is deteriorated.

On the other hand, as shown in FIG. 1A to FIG. 2, in the same manner as the steel sheet 10 for a container according to the present embodiment, the second Ni plating layer 107 can be formed on the composite plating layer 105 to prevent oxygen permeation to the composite plating. The surface of layer 105. Thereby, since oxygen can be prevented from coming into contact with Sn in the composite plating layer 105, generation of oxidized Sn can be suppressed. As a result, in the steel sheet 10 for a container according to the present embodiment, the film adhesion can be improved.

Moreover, the Ni constituting the second Ni plating layer 107 not only enhances the adhesion but also It is also excellent in weldability. Therefore, by forming the second Ni plating layer 107, the weldability of the steel sheet 10 for a container can be improved.

In order to confirm the effect as described above, the content of Ni is required to be 1.0 mg/m ² or more in terms of metal Ni. In addition, the more the Ni content is increased, the more the adhesion and the weldability are improved. However, when the Ni content is converted into a metal Ni amount exceeding 2000 mg/m ² , the adhesion and the weldability tend to be saturated. Therefore, the Ni content is based on an economic point of view, and is calculated to be 2000 mg/m ² or less in terms of the amount of metal Ni.

The Ni content in the second Ni plating layer 107 is preferably 5.0 mg/m ² or more, and more preferably 80 mg/m ² or more, in terms of the amount of metal Ni. By containing Ni in the above range, the adhesion and the weldability can be more reliably improved. Further, the Ni content in the second Ni plating layer 107 is preferably 1500 mg/m ² or less, more preferably 500 mg/m ² or less, in terms of the amount of metal Ni. By limiting the upper limit of the Ni content to the above range, it is possible to improve the adhesion and the weldability while suppressing the cost.

The amount of generation of the Sn oxide layer 121 shown in Fig. 3 can be specified by a well-known method. However, by using the method shown in FIGS. 4A and 4B, the amount of generation of the Sn oxide layer 121 can be easily specified.

The method shown in FIGS. 4A and 4B is a method of specifying the amount of generation of the Sn oxide layer 121 by electrolytic treatment. In this method, the steel sheet 10 for a container in which the composite plating layer 105, the second Ni plating layer 107, and the chemical conversion treatment film layer 109 described later are formed on the steel sheet 103 is used as a test piece.

In more detail, as shown in FIG. 4A, a glass is used. The filter is divided into two zones of electrolytic cells, and a predetermined electrolyte (for example, 0.01% by mass of an aqueous solution of HBr) is injected into the electrolytic cell. Then, a Pt electrode is disposed as an anode in one region of the electrolytic cell, and a reference electrode (for example, an AgCl reference electrode) and a test piece electrode serving as a cathode are disposed in the other region.

Thereafter, a cathodic electrolysis treatment is performed using a potentiostat at a predetermined electrolysis voltage (for example, 1 V) and a constant current (for example, about -1.55 mA). By this cathodic electrolysis treatment, only the Sn oxide layer 121 of the test piece is reduced and electrolyzed. In the cathodic electrolysis treatment, as shown in Fig. 4B, the electrolysis time and the potential were measured. After the two measurement results are patterned, the amount of the Sn oxide layer 121 is specified as the amount of electricity per unit area required for reduction (electrolysis) using the value obtained from the graph (unit: mC/cm). ² ).

When the amount of generation of the Sn oxide layer 121 is X (mC/cm ² ), the amount of production X can be calculated by the following formula (1).

Moreover, the time T required for completely removing the Sn oxide layer 121 can be, for example, a graph of the time-potential curve schematically shown in FIG. 4B, and It is calculated according to the following formula (2).

Here, the chart length L can be obtained in the following manner.

That is, as shown in FIG. 4B, in the time-potential curve when the recovery potential is the horizontal axis and the extraction time is the 緃 axis, the tangent extending in the direction of the potential axis and the tangent extending in the direction of the time axis are specified, and the specific Wait for the intersection of 2 tangent lines. Thereafter, the length from the intersection of the obtained intersection to the vertical line of the potential axis was measured. The length of the vertical line obtained by the above processing becomes the chart length L.

Therefore, the time T required for completely removing the Sn oxide layer 121 can be calculated from the above formula (2) by using the electrolysis conditions and the graph length L obtained from the electrolysis, and the obtained time T and electrolysis conditions can be used according to the above formula ( 1) The amount X of formation of the Sn oxide layer 121 is calculated.

In the steel sheet 10 for a container according to the present embodiment, when the amount of the Sn oxide layer 121 is expressed as the amount of electric power required for reduction, it is preferably 3.0 mC/cm ² or less. When the amount of generation of the Sn oxide layer 121 is expressed as the amount of electric power required for reduction, when it is 3.0 mC/cm ² or less, since the Sn oxide layer 121 does not peel off, the steel sheet 10 for a container has a suitable film. Adhesiveness.

Further, the lower limit of the amount of formation of the Sn oxide layer 121 is not particularly limited, and it is clear from the above description that the amount of generation of the Sn oxide layer 121 is as small as possible.

[About chemical conversion treatment film layer 109]

On the second Ni plating layer 107, as shown schematically in FIGS. 1A and 1B, a chemical conversion treatment film layer 109 is formed. The chemical conversion treatment film layer 109 is a composite film layer mainly composed of a Zr compound, and contains at least a Zr compound of 0.010 to 150 mg/m ² in terms of a metal Zr amount, and is 0.010 to 80 mg/m ² in terms of a P amount. Phosphoric acid compound.

In the present embodiment, the "composite film layer" is a film layer in which a Zr compound and a phosphoric acid compound are not completely mixed and are partially mixed.

When a phosphoric acid film layer having a phosphoric acid compound is formed on a Zr film having a Zr compound, a certain degree of effect can be obtained with respect to corrosion resistance and adhesion, but it is not sufficient in practical use. However, as in the case of the chemical conversion treatment film layer 109 according to the present embodiment, the Zr compound and the phosphoric acid compound in the film layer 109 can be partially mixed by chemical conversion treatment, and excellent corrosion resistance and adhesion can be obtained.

The Zr compound contained in the chemical conversion treatment film layer 109 according to the present embodiment has a function of improving corrosion resistance, adhesion, and process adhesion. Examples of the Zr compound according to the present embodiment include oxidized Zr, phosphoric acid Zr, hydrogenated Zr, and fluorinated Zr. Layer 109 contains several of the foregoing Zr compounds. Since the Zr compound is excellent in corrosion resistance and adhesion, the amount of the Zr compound contained in the chemical conversion treatment film layer 109 increases, and the corrosion resistance and adhesion of the steel sheet 10 for a container increase.

Specifically, when the content of the Zr compound in the chemical conversion treatment film layer 109 is 0.010 mg/m ² or more, when the coating agent is applied onto the chemical conversion treatment film layer 109, it is practically suitable. Adhesion and corrosion resistance to the coating agent. On the other hand, as the content of the Zr compound increases, the adhesion to the coating material and the corrosion resistance are also improved. However, when the content of the Zr compound is converted to a Zr amount exceeding 150 mg/m ² , the adhesion to the coating agent is adhered. Sex and corrosion resistance will be saturated. Therefore, in the steel sheet 10 for a container according to the present embodiment, the content of the Zr compound (that is, the content of Zr) is set to be 0.010 mg/m ² to 150 mg in terms of Zr amount in terms of economy. /m ² .

The appropriate amount of the Zr compound is: in terms of metal Zr content meter ² or less 0.050mg / m ² or more and 120mg / m. By setting the content of the Zr compound to be in the range of 0.050 to 120 mg/m ² in terms of the amount of the metal Zr, it is economically preferable to obtain more suitable corrosion resistance and adhesion such as coating.

The chemical conversion treatment film layer 109 further contains one or more kinds of phosphoric acid compounds in addition to the Zr compound.

The phosphoric acid compound according to the present embodiment has a function of improving corrosion resistance, adhesion, and process adhesion. Examples of the phosphoric acid compound according to the present embodiment include a phosphate ion, a steel sheet 103, and a composite plating layer 105. Phosphoric acid Fe, phosphoric acid Sn, phosphoric acid Ni, and phosphoric acid Zr formed by the reaction of the second Ni plating layer 107 and the compound contained in the chemical conversion treatment film layer 109. The chemical conversion treatment film layer 109 contains at least one of the aforementioned phosphoric acid compounds.

Since the phosphoric acid compound is excellent in corrosion resistance and adhesion, the more the amount of the phosphoric acid compound, the higher the corrosion resistance and the adhesion of the steel sheet 10 for a container.

Specifically, in consideration of the content of the Zr compound, if the content of the phosphoric acid compound in the chemical conversion treatment film layer 109 is converted to a P content of 0.010 mg/m ² or more, practically suitable adhesion to the coating agent can be obtained. Corrosion resistance. On the other hand, with the increase in the content of the phosphoric acid compound, the adhesion to the coating material and the corrosion resistance are also improved. However, when the content of the phosphoric acid compound is more than 80 mg/m ² , the adhesion to the coating agent is increased. And the corrosion resistance will be saturated. Thus, the container related to the present embodiment, the steel sheet 10, the content of phosphoric acid compound in terms of P content is set in terms of ^{0.010mg / m 2 ~ 80mg / m} 2.

The content of the compound is suitably phosphoric acid: in terms of the amount of ² or less in terms of P 0.050mg / m ² or more and 60mg / m. When the content of the phosphoric acid compound is in the above range, more excellent adhesion to the coating agent and corrosion resistance can be obtained, which is economically preferable.

As described above, the configuration of the steel sheet 10 for a container according to the present embodiment will be described in detail with reference to Figs. 1A to 4B.

As shown in Fig. 5, the coating material for the application can be applied to the container on the outermost surface of the steel sheet 10 for a container (i.e., the surface of the chemical conversion treatment coating layer 109) according to the present embodiment. A coating layer 151 is formed on the outermost surface of the steel sheet 10. The cover layer 151 is subjected to the following addition It is formed by heat treatment. After the treatment liquid is applied to the chemical conversion treatment film layer 109, the temperature is about 210 ° C when the coating film is formed, and the temperature is about 160 ° C when the film is laminated. .

At least a part of the composite plating layer 105 is melted when heat treatment is to be carried out to reach the above-mentioned reaching temperature. As a result, Sn contained in the composite plating layer 105 reacts with Ni contained in the second Ni plating layer 107 to be alloyed, and as shown in FIG. 5, the composite plating layer 105 and the second Ni plating are performed. The Ni-Sn alloy layer 153 is formed at the interface of the cladding layer 107. Since the Ni-Sn alloy layer 153 is excellent in corrosion resistance, the coating layer 151 is further formed by the upper layer of the chemical conversion treatment film layer 109, and the corrosion resistance of the steel sheet 10 for a container is further improved.

<Method for measuring the content of ingredients>

Here, the amount of metal Sn and the amount of metal Ni in the composite plating layer 105 and the amount of metal Ni in the second Ni plating layer 107 can be measured by, for example, X-ray fluorescence. At this time, using a Sn adhesion amount sample of a known metal Sn amount, a calibration curve regarding the amount of metal Sn is specified in advance, and the amount of metal Sn is relatively specified by the same amount of measurement curve. Similarly, using a Ni adhesion amount sample of a known metal Ni amount, a calibration curve regarding the amount of metal Ni is specified in advance, and the amount of metal Ni is relatively specified by the same amount of measurement curve.

Further, the amount of metal Zr and the amount of P in the chemical conversion treatment film layer 109 can be measured by a quantitative analysis method such as fluorescent X-ray analysis. Further, what kind of compound is present in the chemical conversion treatment film layer 109 can be specified by analysis by X-ray photoelectron spectroscopy (XPS).

In addition, the method of measuring each component amount is not limited to the above method, and Other well-known assay methods are applicable.

Further, in the steel sheet 10 for a container according to the present embodiment, as described above, Ni is present in both of the composite plating layer 105 and the second Ni plating layer 107. However, the adhesion amount of Ni in each layer is exemplified. In other words, it can be specified in the following ways. In other words, after measuring the total amount of Ni of the steel sheet 10 for a container by the X-ray fluorescence method, X-ray diffraction analysis (XRD) and Glow Discharge Spectroscopy (GDS) were carried out. Determination. According to the GDS, the measurement results as shown in Fig. 6 can be obtained.

First, the interface between the second Ni plating layer 107 and the composite plating layer 105 is determined by analyzing the Fe-Ni-Sn alloy by XRD. Specifically, first, a sample having a thickness of about 10 μm was produced using Focused Ion Beam. For the sample obtained in the above manner, the Fe-Ni-Sn alloy was analyzed by XRD. The depth position on the outermost surface side of the depth position of the Fe-Ni-Sn alloy was detected as the interface between the second Ni plating layer 107 and the composite plating layer 105. Further, the depth position on the side of the steel sheet 103 among the depth positions of the Fe-Ni-Sn alloy was detected as the interface between the composite plating layer 105 and the steel sheet 103.

Further, the interface between the composite plating layer 105 and the steel sheet 103 can be determined based on the XRD result of the metal Fe. The composite plating layer 105 does not contain metal Fe, and the steel sheet 103 contains metal Fe. Therefore, compared with the interface between the second Ni plating layer 107 and the composite plating layer 105, the XRD of the metal Fe can be performed at the depth position on the side of the steel sheet 103, and the depth position at which the metal Fe is initially detected is determined as The interface between the composite plating layer 105 and the steel sheet 103.

Interface between the second Ni plating layer 107 and the composite plating layer 105 and composite plating The method of determining the interface between the layer 105 and the steel sheet 103 is not limited to the above method, and a well-known method can be used. For example, the interface between the second Ni plating layer 107 and the composite plating layer 105 and the interface between the composite plating layer 105 and the steel sheet 103 may be determined using an analysis method other than XRD for the sample obtained by FIB.

The interface between the second Ni plating layer 107 and the composite plating layer 105 and the interface between the composite plating layer 105 and the steel sheet 103 are determined by the above method. Then GDS is performed to analyze the Ni distribution in the depth direction. Specifically, the area of the Ni detected signal intensity (the area of B in FIG. 6) existing in the depth position of the composite plating layer 105 and the Ni detected in the depth position of the second Ni plating layer 107 are determined. The ratio of the area of the signal intensity (area of A in Figure 6). The amount of Ni attached to each layer can be specified by using the area ratio obtained by the above method and allocating the total amount of Ni obtained by the X-ray fluorescence method.

<Method of Manufacturing Steel Sheet 10 for Container>

Next, a method of manufacturing the steel sheet 10 for a container according to the present embodiment will be described in detail with reference to Fig. 6 . Fig. 6 is a flow chart for explaining an example of a flow of a method of manufacturing the steel sheet 10 for a container according to the present embodiment.

[Pre-Processing Steps]

In the method of manufacturing the steel sheet 10 for a container according to the present embodiment, first, the steel sheet 103 is subjected to a well-known pretreatment as required (step S101).

[First Ni plating layer forming step]

Thereafter, a first Ni plating layer (not shown) is formed on the surface of the steel sheet 103 (step S103). As a method of forming the first Ni plating layer, for example, A well-known method (e.g., cathodic electrolysis) generally performed in electroplating can be utilized.

When the first Ni plating layer (not shown) is formed by a diffusion plating method, diffusion treatment is performed on the surface of the steel sheet 103 after Ni plating is applied to form a diffusion layer in the annealing furnace. The nitriding treatment may also be performed before or after the diffusion treatment. Even if the nitriding treatment is performed, the corrosion improving effect of Ni is not eliminated by the nitriding treatment layer.

[Sn plating layer forming step]

After the first Ni plating layer (not shown) is formed, a Sn plating layer (not shown) is formed (step S105). The method of forming the Sn plating layer (not shown) is not particularly limited, but for example, it is preferable to use, for example, a well-known plating method, or a first Ni plating layer (not shown) may be used. The method in which the steel sheet 103 is immersed in the molten Sn or the like.

[Molten tin treatment (reflow processing) step]

After the Sn plating layer (not shown) is formed, molten tin treatment (reflow processing) is performed (step S107). The purpose of the molten tin treatment is to melt the Sn and alloy it with the steel sheet 103 and the Ni plating of the base, and form the Fe-Ni-Sn alloy layer 105a to improve the corrosion resistance of the alloy layer. An island-shaped Sn layer 105b composed of an island-shaped Sn alloy is formed. The island-shaped Sn alloy can be formed by appropriately controlling the molten tin treatment.

[Second Ni plating layer forming step]

After the composite plating layer 105 is formed, the second Ni plating layer 107 is formed (step S109).

The second Ni plating layer 107 can be utilized by using a Ni plating bath containing Ni ions. It is known to be formed by a plating process. The Ni plating bath of the present embodiment contains 10 g/L or more of sulfate ions and 30 g/L or more of Ni ions.

When the Ni plating bath does not contain Cl ions, it is preferable to contain 75 to 90 g/L of sulfate ions and 40 to 55 g/L of Ni ions. By setting the concentration of the sulfate ion to 75 g/L or more and the concentration of the Ni ion to 40 g/L or more, the Ni content in the second Ni plating layer 107 can be set to an appropriate range.

Further, by setting the concentration of the sulfate ion to 90 g/L or less and the concentration of the Ni ion to 55 g/L or less, the Ni content in the second Ni plating layer 107 can be set to an appropriate range, which is economical. It is also ideal.

The Ni plating bath may also contain Cl ions. When the Ni plating bath contains Cl ions, the Ni plating bath preferably contains 20 to 40 g/L of sulfuric acid ions, 40 to 55 g/L of Ni ions, and 35 to 45 g/L of Cl ions. By setting the concentration of the sulfate ion to 20 g/L or more, setting the concentration of the Ni ion to 40 g/L or more, and setting the concentration of the Cl ion to 35 g/L or more, the second Ni plating layer 107 can be used. The Ni content is set in a suitable range.

Further, by setting the concentration of the sulfate ion to 40 g/L or less, setting the concentration of the Ni ion to 55 g/L or less, and setting the concentration of the hydrochloric acid ion to 45 g/L or less, the second Ni plating layer 107 can be provided. The Ni content in the range is suitable and economically desirable.

The Ni plating bath may further contain 30 g/L or more of boric acid ions. By adding boric acid ions to the Ni plating bath, it is possible to suppress the pH rise of the Ni plating bath accompanying the plating treatment. Further, the content of the boric acid ion is preferably 40 g/L or more and 50 g/L or less. By setting the content of the boric acid ions to 40 g/L or more, the pH rise of the Ni plating bath can be more reliably suppressed. Again, by boric acid The content of the sub-component is set to 50 g/L or less, and the pH rise of the Ni plating bath can be suppressed, which is economically preferable.

[Chemical conversion treatment film layer formation step]

Then, the chemical conversion treatment film layer 109 is formed on the second Ni plating layer 107 by performing cathodic electrolysis treatment or immersion treatment (step S111).

The chemical conversion treatment bath used for the cathodic electrolysis treatment or the immersion treatment contains Zr ions of 10 ppm or more and 20,000 ppm or less, F ions of 10 ppm or more and 20000 ppm or less, phosphate ions of 10 ppm or more and 3000 ppm or less, and a total of 100 ppm or more and 30000 ppm or less. Nitric acid ions and sulfate ions.

When the amount of F ions added is less than 10 ppm, F which forms a complex compound with Zr ions becomes small, and Zr does not adhere, which is not preferable. Further, when the amount of F ions added exceeds 20,000 ppm, Zr is excessively adhered, which is not preferable.

When the amount of the nitrate ions added is less than 100 ppm, the amount of nitric acid which increases the adhesion efficiency of the Zr ions is reduced, and the amount of adhesion of Zr is lowered, which is not preferable. Further, when the amount of the nitrate ions added exceeds 30,000 ppm, Zr is excessively adhered, which is not preferable.

When the amount of the sulfate ion added is less than 100 ppm, the amount of sulfuric acid which increases the adhesion efficiency of Zr ions is reduced, and the amount of adhesion of Zr is lowered, which is not preferable. Further, when the amount of the sulfate ion added exceeds 30,000 ppm, Zr is excessively adhered, which is not preferable.

In addition, the nitrate ion and the sulfate ion may be 100 ppm or more and 30,000 ppm or less in total in the chemical conversion treatment bath, and nitric acid may be used. Both the ion and the sulfate ion are contained in the chemical conversion treatment bath, and the sulfuric acid ion and the sulfate ion may be contained in the chemical conversion treatment bath.

The chemical conversion treatment bath preferably contains 50 ppm or more and 17,000 ppm or less of Zr ions, 50 ppm or more and 17,000 ppm or less of F ions, 50 ppm or more and 2500 ppm or less of phosphate ions, and a total of 300 ppm or more and 27,000 ppm or less of nitrate ions and sulfate ions.

By setting the addition amount of Zr ions to 50 ppm or more, it is possible to more reliably prevent the adhesion amount of Zr ions from being lowered. Moreover, by setting the addition amount of F ions to 50 ppm or more, it is possible to more reliably prevent the white turbidity of the chemical conversion treatment film accompanying the precipitation of phosphate. Similarly, by setting the addition amount of the phosphate ion to 50 ppm or more, the white turbidity of the chemical conversion treatment film accompanying the precipitation of phosphate can be more reliably prevented. In addition, by setting the total addition amount of the nitrate ion and the sulfate ion to 300 ppm or more, it is possible to more reliably prevent a decrease in the adhesion efficiency of the chemical conversion treatment film. Further, by setting the upper limit of each additive component to the value as described above, the manufacturing cost of the chemical conversion treatment film layer 109 can be more reliably reduced.

Further, a phenol resin or the like may be further added to the chemical conversion treatment bath. When a phenol resin is added to the chemical conversion treatment bath, the phenol resin can be denatured to make it water-soluble.

Further, tannic acid may be further added to the chemical conversion treatment bath. By adding tannic acid to the chemical conversion treatment bath, tannic acid reacts with Fe in the steel sheet 103 to form a film of tannic acid Fe on the surface of the steel sheet 103. The film of tannic acid Fe is desirable for improving rust resistance and adhesion.

The pH of the chemical conversion treatment bath is preferably from 3.1 to 3.7, preferably at 3.5. about. In order to adjust the pH, nitric acid or ammonia or the like may be added to the chemical conversion treatment bath.

Further, the temperature of the chemical conversion treatment bath is preferably set to 5 ° C or more and less than 90 ° C. When the temperature of the chemical conversion treatment bath is less than 5 ° C, the formation efficiency of the chemical conversion treatment coating layer 109 is uneconomical, which is not preferable. Further, when the temperature of the chemical conversion treatment bath is 90 ° C or more, the structure of the coating layer 109 due to the chemical conversion treatment is uneven, and bismuth, cracking, microcracks, and the like may occur, and this portion may become a starting point for corrosion or the like, which is not preferable. .

When the chemical conversion treatment film layer 109 is formed by electrolytic treatment (cathode electrolytic treatment), it is preferable to have a current density of 0.5 A/dm ² or more and 20 A/dm ² or less and 0.05 second or more and 10 seconds or less. The cathode electrolysis treatment time is implemented.

When the current density is less than 0.5 A/dm ² , the amount of adhesion of the chemical conversion treatment film layer 109 is lowered, and the cathodic electrolysis treatment time is prolonged to lower the productivity, which is not preferable. Further, when the current density exceeds 20 A/dm ² , the adhesion amount of the chemical conversion treatment film layer 109 becomes excessive, and depending on the case, the chemical conversion treatment film layer 109 which is insufficiently adhered in the cleaning step after the chemical conversion treatment is used. It will be washed away (peeled), so it is not ideal.

When the cathode electrolysis treatment time is less than 0.05 seconds, the adhesion amount of the coating layer 109 due to the chemical conversion treatment is lowered, and the adhesion resistance and the adhesion such as coating are lowered, which is not preferable. When the cathodic electrolysis treatment time exceeds 10 seconds, the adhesion amount of the film layer 109 due to the chemical conversion treatment becomes excessive, and the chemical conversion treatment film layer 109 which is insufficiently adhered in the washing step after the chemical conversion treatment is washed away ( Stripping), it is not ideal.

When the chemical conversion treatment film layer 109 is formed by the immersion treatment using the chemical conversion treatment bath, the immersion treatment time of immersing the plated steel sheet 101 in the chemical conversion treatment bath is preferably 0.2 to 100 seconds. When the immersion treatment time is less than 0.2 second, the amount of adhesion of the chemical conversion treatment film layer 109 is lowered, and the immersion treatment time is prolonged to lower the productivity, which is not preferable. Further, when the immersion treatment time exceeds 100 seconds, the adhesion amount of the chemical conversion treatment film layer 109 becomes excessive, and depending on the case, the chemical conversion treatment film layer 109 which is insufficiently adhered in the washing step after the immersion treatment may It is washed away (peeled), so it is not ideal.

Further, as the solvent for the chemical conversion treatment bath for forming the chemical conversion treatment coating layer 109 according to the present embodiment, for example, deionized water, distilled water or the like can be used. Further, when the chemical conversion treatment film layer 109 is formed by cathodic electrolysis treatment, the conductivity of the solvent is preferably considered, and the desired conductivity of the solvent is preferably 10 μS/cm or less, more preferably 5 μS/cm or less. It is below 3 μS/cm. The solvent of the chemical conversion treatment bath is not limited thereto, and may be appropriately selected depending on the material to be melted, the formation method, and the formation conditions of the chemical conversion treatment coating layer 109. Deionized water and distilled water should be used from the viewpoint of industrial productivity, cost and environment based on stability of the stability of each component.

In the chemical conversion treatment bath used for the formation of the chemical conversion treatment coating layer 109 according to the present embodiment, a Zr complex such as H ₂ ZrF ₆ can be used as a supply source of Zr. The Zr in the Zr complex is present in the chemical conversion solution due to the hydrolysis reaction to Zr ⁴⁺ . The Zr ions are rapidly reacted in the chemical conversion treatment bath, and a compound such as ZrO ₂ and Zr ₃ (PO ₄ ) ₄ is formed, and becomes dehydratable with a hydroxyl group (-OH) present on the surface of the metal. A Zr film is formed by a condensation reaction or the like.

[post-processing steps]

Thereafter, the steel sheet 103 on which the composite plating layer 105, the second Ni plating layer 107, and the chemical conversion coating layer 109 have been formed is subjected to a well-known post-processing (step S113).

The steel sheet for a container 10 according to the present embodiment can be produced by the above-described process.

Example

Hereinafter, a method for producing a steel sheet for a container and a steel sheet for a container according to the present embodiment will be specifically described with reference to the embodiments. In addition, the embodiment shown below is an example of the manufacturing method of the steel plate for containers and the steel plate for containers according to the present embodiment, and the method for producing the steel sheet for containers and the steel sheet for containers according to the present embodiment is not limited. The following examples.

[Example 1]

The steel sheet for containers in which the composite plating layer, the second Ni plating layer, and the chemical conversion treatment film layer were formed on the steel sheet was used as a test material, and the film adhesion was investigated. The content of Sn and the content of Ni in the composite plating layer of each of the examples and the comparative examples, the content of Ni in the second Ni plating layer, the content of the Zr compound in the chemical conversion treatment coating layer, and the content of the phosphoric acid compound are shown in the table. 1. Moreover, the adhesion amount of each plating layer was measured by X-ray fluorescence method, XRD, and GDS.

[Measurement of film adhesion]

For one side of each test material, a PET film 160 having a thickness of 20 μm was laminated on The steel plate 10 for containers is used. Thereafter, it was press-formed into a can bottom type as shown in Fig. 7, and subjected to a autoclave treatment at a temperature of 125 ° C for 30 minutes using a high pressure steam sterilizer.

The peeling condition of the PET film 160 was observed, and the ratio of the area of the peeling portion in the entire surface area of the inner side of the bottom of the PET film 160 (the side in contact with the contents of the can) was evaluated in four stages. The evaluation criteria of the film adhesion are as follows.

Further, each of the test materials after the autoclave treatment was observed by XRD (X-ray diffraction), and it was confirmed that a Ni-Sn alloy layer was formed.

[Evaluation criteria for film adhesion]

Very good: peeling area ratio: 0%~10%

Good: peeling area ratio: more than 10% and less than 20%

Bad: peeling area ratio: more than 20% and less than 50%

Inferior: peeling area ratio: more than 50%

It is clear from Table 1 that the examples have excellent film adhesion. Further, in the comparative examples, the film adhesion was poor.

[Embodiment 2]

The plated steel sheet on which the composite plating layer was formed was subjected to Ni plating using a Ni plating bath containing the components shown in Table 2. The Ni content of the formed second Ni plating layer is shown in Table 2.

For the plated steel sheet on which the composite plating layer and the second Ni plating layer have been formed, a chemical conversion treatment bath having the components shown in Table 3 is used, and a chemical conversion treatment film layer is formed through immersion treatment or cathodic electrolysis treatment. .

The content of the Zr compound and the content of the phosphoric acid compound in the chemical conversion coating layer formed were shown in Table 4. Further, the amount of formation of the Sn oxide layer was measured by the method shown in Figs. 4A and 4B. The measurement results are shown in Table 4.

The steel sheet for a container in which the composite plating layer, the second Ni plating layer, and the chemical conversion treatment film layer were formed on the steel sheet was used as a test piece, and the film adhesion was evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

As is apparent from Table 4, it is clear that the examples relating to the present embodiment have suitable film adhesion. On the other hand, it is clear that the comparative example has poor film adhesion.

Although the preferred embodiments of the present invention have been described above with reference to the drawings, the invention is not limited to the examples. As long as there is a general knowledge in the technical field to which the present invention pertains, various modifications and modifications can be conceived within the scope of the technical scope of the invention as set forth in the appended claims. The technical scope of the invention.

Industrial availability

According to the above embodiment, a steel sheet for a container having excellent film adhesion and a method for producing a steel sheet for a container can be provided.

10‧‧‧Steel plates for containers

101‧‧‧ plated steel plate

103‧‧‧ steel plate

105‧‧‧Composite plating

107‧‧‧Second Ni plating layer (metal Ni plating layer)

109‧‧‧Chemical conversion treatment of the film layer

Claims (7)

A steel sheet for a container, comprising: a steel sheet; and a composite plating layer, which is an upper layer of the steel sheet, and contains Ni in an amount of 2.0 to 200 mg/m ^{2 in terms} of a metal Ni content, and 0.10 in terms of a metal Sn amount. ~10.0g/m ² of Sn, and an island-shaped Sn layer is formed on the Fe-Ni-Sn alloy layer; the metal Ni plating layer is used as the upper layer of the composite plating layer, and is contained in the amount of metal Ni Ni of 1.0 to 2000 mg/m ² ; and a chemical conversion treatment film layer, which is an upper layer of the metal Ni plating layer, and contains a Zr compound in an amount of 0.010 to 150 mg/m ^{2 in terms} of a metal Zr amount, and is converted into a P amount. It is a phosphate compound of 0.010 to 80 mg/m ² . The steel sheet for containers according to claim 1, wherein the composite plating layer contains Ni in an amount of 5.0 to 150 mg/m ^{2 in terms} of metal Ni, and Sn in an amount of 0.5 to 7.0 g/m ^{2 in terms} of metal Sn. The steel sheet for containers according to claim 1 or 2, wherein the metal Ni plating layer contains Ni in an amount of 5.0 to 1500 mg/m ^{2 in terms} of metal Ni. The steel sheet for containers according to any one of claims 1 to 3, wherein the chemical conversion treatment film layer contains the Zr compound in an amount of from 0.050 to 120 mg/m ^{2 in terms} of metal Zr. The steel sheet for containers according to any one of claims 1 to 4, wherein the chemical conversion treatment film layer contains the phosphoric acid compound in an amount of 0.050 to 60 mg/m ^{2 in terms} of P. The steel sheet for containers according to any one of claims 1 to 5, further comprising a Sn oxide layer between the composite plating layer and the metal Ni plating layer, wherein the Sn oxide layer contains a reduction oxide layer The amount of electricity is 3.0 mC/cm ² or less of oxidized Sn. A method for producing a steel sheet for a container, comprising the steps of: forming a first Ni plating layer on a steel sheet to form a Ni containing 2.0 to 200 mg/m ^{2 in terms} of a metal Ni content; a Ni plating layer; a Sn plating layer forming step of forming a Sn plating layer containing Sn in an amount of 0.10 to 10.0 g/m ^{2 in terms} of a metal Sn amount on the first Ni plating layer; a tin treatment step of forming a composite plating layer having an island-shaped Sn layer on the Fe-Ni-Sn alloy layer by performing a molten tin treatment; and a second Ni plating layer forming step of the molten tin After the treatment step, a Ni plating bath containing 10 g/L or more of sulfate ions and 30 g/L or more of Ni ions is used to form a second Ni plating layer on the composite plating layer; and a chemical conversion treatment film layer is formed. After the second Ni plating layer forming step, the following chemical conversion treatment bath is used, and the cathode electrolysis treatment time is performed at a current density of 0.5 to 20 A/dm ² and 0.05 to 10 seconds. Cathodic electrolysis treatment, or impregnation with 0.2 to 100 seconds of immersion treatment time And forming a chemical conversion treatment coating layer on the second Ni plating layer; the chemical conversion treatment bath contains 10 to 20000 ppm of Zr ions, 10 to 20000 ppm of F ions, 10 to 3000 ppm of phosphoric acid ions, and a total of 100~ 30000ppm of nitrate ions and sulfate ions, and the temperature is 5~90 °C.