JP5994960B1 - Steel plate for container and method for producing steel plate for container - Google Patents

Abstract

As this steel plate for containers, as an upper layer of the steel plate, an Sn plating layer containing 0.1 to 15 g / m 2 of Sn or Fe—Sn alloy in terms of the amount of metal Sn, and an upper layer of the Sn plating layer A metal Ni plating layer containing 1 to 2000 mg / m2 of Ni in terms of metal Ni, and an upper layer of the metal Ni plating layer, 0.01 to 150 mg / m2 of Zr compound in terms of metal Zr, And a chemical conversion film layer containing 0.01 to 80 mg / m 2 of a phosphoric acid compound in terms of P amount.

Description

The present invention relates to a steel plate for containers and a method for producing a steel plate for containers.
This application claims priority on January 9, 2015 based on Japanese Patent Application No. 2015-3596 for which it applied to Japan, and uses the content for it here.

As containers for beverages or foods, metal containers made of Sn-plated steel sheets or Sn-based alloy-plated steel sheets are often used. In such a metal container, it is necessary to coat the surface of the metal container before or after canning. However, in recent years, from the viewpoint of global environmental conservation, in order to reduce waste caused by paints such as waste solvents and exhaust gases such as carbon dioxide, films are often laminated instead of coating. In addition, the steel plate used for a metal container is called a steel plate for containers.
Rust prevention by chromate using hexavalent chromate, etc. to ensure adhesion and corrosion resistance to the coating agent on the steel plate for containers used for the base of paint or film (hereinafter referred to as coating agent) A treatment (hereinafter referred to as a chromate treatment) is often performed (see, for example, Patent Document 1 below).

  However, recently, hexavalent chromium used for chromate treatment is harmful to the environment. Therefore, it has been studied to replace chromate treatment conventionally applied to steel plates for containers with other surface treatments. That is, there is a need for a surface treatment that is applied to the surface of the steel plate for containers and that has excellent adhesion to the coating agent and excellent corrosion resistance. 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 a chromate treatment.

Japanese Unexamined Patent Publication No. 2000-239855 Japanese Unexamined Patent Publication No. 2007-284789

  Conventionally, steel plates that have been subjected to chromate treatment after forming an Sn plating layer have been used as a material for metal containers that require corrosion resistance such as a three-piece can used for storage of acidic beverages. However, as a result of the study by the present inventors, in place of the chromate treatment, a chemical conversion treatment using a chemical conversion treatment bath containing Zr and phosphoric acid as disclosed in Patent Document 2 is carried out, and formed by chemical conversion treatment. It has become clear that when a film is laminated on a coating layer (hereinafter referred to as a chemical conversion coating layer), the adhesion between the steel plate for containers and the film is lowered.

  This invention is made | formed in view of said situation, and it aims at providing the manufacturing method of the steel plate for containers which has the outstanding film adhesiveness, and the steel plate for containers.

The present inventors diligently studied the adhesion between the chemical conversion coating layer and the film laminated on the chemical conversion coating layer. As a result, it was found that an Sn oxide layer containing Sn oxide was formed at the interface between the chemical conversion treatment film layer and the Sn plating layer because oxygen penetrated into the chemical conversion treatment film layer. Further, the present inventors have found that since the Sn oxide layer is fragile, when the Sn oxide layer is formed thick, the Sn oxide layer may be peeled off and the film adhesion may be deteriorated. did.
The present invention employs the following means in order to solve the above problems and achieve the object.

(1) The steel plate for containers which concerns on 1 aspect of this invention is Sn plating containing 0.1-15 g / m < ² > of Sn or a Fe-Sn alloy in conversion to the amount of metal Sn as an upper layer of a steel plate and the said steel plate. As an upper layer of the Sn plating layer, a metal Ni plating layer containing 1 to 2000 mg / m ² of Ni in terms of metal Ni, and 0 as a metal Zr amount as the upper layer of the Ni plating layer A chemical conversion coating layer containing 0.01 to 150 mg / m ² of a Zr compound and 0.01 to 80 mg / m ² of a phosphoric acid compound in terms of P amount.

(2) In the steel plate for containers described in (1) above, the Sn plating layer adopts a configuration containing 0.3 to 11 g / m ² of Sn or Fe—Sn alloy in terms of the amount of metal Sn. May be.

(3) In the steel plate for containers described in the above (1) or (2), the Ni plating layer may adopt a configuration containing 5 to 1500 mg / m ² Ni in terms of the amount of metal Ni. .

(4) In the steel plate for containers according to any one of the above (1) to (3), the chemical conversion coating layer is 0.05 to 120 mg / m ² of the Zr in terms of the amount of metal Zr. You may employ | adopt the structure containing a compound.

(5) In the steel plate for containers according to any one of the above (1) to (4), the chemical conversion treatment film layer is 0.05 to 60 mg / m ² phosphoric acid compound in terms of P amount. You may employ | adopt the structure containing this.

(6) In the steel plate for containers according to any one of the above aspects (1) to (5), the amount of electricity required for reduction is 8 mC / cm ² or less between the Sn plating layer and the metal Ni plating layer. A configuration further comprising a Sn oxide layer containing Sn oxide Sn may be adopted.

(7) The manufacturing method of the steel plate for containers which concerns on 1 aspect of this invention, Sn plating layer formation process which forms Sn plating layer which contains 0.1-15 g / m < ² > of Sn by the amount of metal Sn on a steel plate, A metal Ni plating layer that forms a metal Ni plating layer on the Sn plating layer using a Ni plating bath containing 10 g / L or more of sulfate ions and 30 g / L or more of Ni ions after the Sn plating layer forming step. After the forming step and the metal Ni plating layer forming step, the temperature contains 10 to 20000 ppm of Zr ions, 10 to 20000 ppm of F ions, 10 to 3000 ppm of phosphate ions, and 100 to 30000 ppm of nitrate ions and sulfate ions in total. shade but with the chemical treatment bath is 5 to 90 ° C., it is carried out by cathodic electrolytic treatment time of the current density 0.5~20A / dm ² and 0.05 to 10 seconds By performing the immersion process performed by immersion treatment time of electrolytic treatment or 0.2 to 100 seconds, with a, a chemical conversion coating layer-forming step of forming a chemical conversion coating layer on the metal Ni plating layer.

  According to each said aspect, it is possible to provide the manufacturing method of the steel plate for containers which has the outstanding film adhesiveness, and the steel plate for containers.

It is explanatory drawing which showed typically the layer structure of the steel plate for containers which concerns on this embodiment. It is explanatory drawing which showed typically the layer structure of the steel plate for containers which concerns on this embodiment. It is explanatory drawing which showed typically the structure of the Sn plating layer of the steel plate for containers which concerns on this embodiment. It is explanatory drawing which showed typically the structure of the Sn plating layer of the steel plate for containers which concerns on this embodiment. It is explanatory drawing regarding formation of Sn oxide layer at the time of using a prior art. It is explanatory drawing for demonstrating the measuring method of the production amount of Sn oxide. It is explanatory drawing for demonstrating the measuring method of the production amount of Sn oxide. It is explanatory drawing regarding the case where a coating agent is apply | coated to the surface of the steel plate for containers which concerns on this embodiment. It is the flowchart which showed an example of the flow of the manufacturing method of the steel plate for containers which concerns on this embodiment. It is explanatory drawing for demonstrating an Example.

  Hereinafter, a steel plate for containers and a method for manufacturing a steel plate for containers according to embodiments will be described in detail with reference to the accompanying drawings. In the present embodiment, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<About the structure of the steel plate 10 for containers>
Below, the structure of the steel plate 10 for containers which concerns on this embodiment is demonstrated in detail, referring FIG. 1A-FIG.
Drawing 1A and Drawing 1B are explanatory views showing typically a layer structure at the time of seeing steel plate 10 for containers concerning this embodiment from the side. 2A and 2B are explanatory views schematically showing the configuration of the Sn plating layer of the steel plate for containers 10 according to the present embodiment. FIG. 3 is an explanatory diagram for explaining the formation of the Sn oxide layer when the conventional technique is used. 4A and 4B are explanatory diagrams for explaining a method for measuring the amount of Sn oxide produced. Drawing 5 is an explanatory view about the case where a coating agent is applied to the surface of steel plate 10 for containers concerning this embodiment.

As shown in FIGS. 1A and 1B, the steel plate 10 for containers according to the present embodiment includes a plated steel plate 101 and a chemical conversion treatment film layer 109. Here, the plated steel plate 101 includes a steel plate 103 as a base material, an Sn plating layer 105 formed on the steel plate 103, and a metal Ni plating layer 107 formed on the Sn plating layer 105. . In addition, the Sn plating layer 105, the metal Ni plating layer 107, and the chemical conversion treatment film layer 109 may be formed only on one surface of the steel plate 103 as shown in FIG. 1A, or as shown in FIG. 1B. In addition, it may be formed on two surfaces of the steel plate 103 facing each other.
The Sn plating layer 105 is in contact with the surface of the steel plate 103, the metal Ni plating layer 107 is in contact with the surface of the Sn plating layer 105, and the chemical conversion coating layer 109 is in contact with the surface of the metal Ni plating layer 107. .

[About steel plate 103]
The steel plate 103 is used as a base material of the container steel plate 10 according to the present embodiment. The steel plate 103 used in the present embodiment is not particularly limited, and it is possible to use a known steel plate 103 that is usually used as a container material. There is no particular limitation on the manufacturing method and material of these known steel plates. The steel plate 103 manufactured through known steps such as hot rolling, pickling, cold rolling, annealing, and temper rolling can be used from the normal billet manufacturing process.

[Sn plating layer 105]
On the surface of the steel plate 103, a barrier-type Sn plating layer 105 containing at least Sn is formed as an upper layer of the steel plate 103. Here, the barrier-type plating layer is formed by forming Sn metal film on the surface of the steel plate 103 using Sn that is electrochemically noble than Fe constituting the base material steel plate 103. It is a plating layer that prevents corrosion of the steel sheet 103 by preventing the corrosion factor from acting on the base material.

  Hereinafter, an example of the Sn plating layer 105 according to the present embodiment will be specifically described with reference to FIGS. 2A and 2B. 2A and 2B, the case where the Sn plating layer 105, the metal Ni plating layer 107, and the chemical conversion treatment film layer 109 are formed only on one surface of the steel plate 103 is illustrated for convenience.

  The Sn plating layer 105 is formed on at least one surface of the steel plate 103. As schematically illustrated in FIG. 2A, the Sn plating layer 105 may be configured by only the Sn layer 105 a containing metal Sn as a main component. As schematically shown in FIG. 2B, the Sn plating layer 105 includes an Fe—Sn alloy layer 105b made of an Fe—Sn alloy and an Sn layer 105a formed on the Fe—Sn alloy layer 105b. May be.

  The Fe—Sn alloy layer 105b shown in FIG. 2B is formed by forming a Sn layer 105a on the steel plate 103 by Sn plating, and then forming a part of the Sn layer 105a by alloying with Fe of the steel plate 103 by molten tin treatment (reflow treatment). By forming, it can be formed in the lower layer of the Sn layer 105a. After the Sn layer 105a is formed on the steel plate 103 by the Sn plating process, when the molten tin process is not performed, the Sn plating layer 105 is composed only of the Sn layer 105a as shown in FIG. 2A. .

The ratio of the thicknesses of the Sn layer 105a and the Fe—Sn alloy layer 105b is not particularly limited, and it is sufficient that an adhesion amount described later is ensured in the entire Sn plating layer 105.
The “Sn plating” in the present embodiment is not limited to the case of being composed of only metal Sn, but may include impurities in addition to metal Sn, and may include trace elements in addition to metal Sn.

  The Sn plating layer 105 is formed to ensure the corrosion resistance and weldability of the steel plate 10 for containers. Since Sn itself has high corrosion resistance, it exhibits excellent corrosion resistance and weldability both as metal Sn and as an alloy Sn formed by the molten tin treatment described below.

The Sn plating layer 105 contains 0.1 to 15 g / m ² of Sn or Fe—Sn alloy in terms of the amount of metal Sn.
That is, as shown to FIG. 2A, when Sn plating layer 105 is comprised only by Sn layer 105a, Sn content of Sn layer 105a is 0.1-15 g / m < ² > converted into metal Sn amount. It is. In addition, as shown in FIG. 2B, when the Sn plating layer 105 is composed of the Sn layer 105a and the Fe—Sn alloy layer 105b, the total Sn content of the Sn layer 105a and the Fe—Sn alloy layer 105b is It is 0.1 to 15 g / m ² in terms of the amount of metal Sn.

Sn has excellent workability, weldability and corrosion resistance, but it can be further improved in corrosion resistance by performing molten tin treatment after Sn plating, and also has a suitable surface appearance (mirror appearance) Can be.
In order to express the above-mentioned effect reliably, it is necessary that the Sn content of the entire Sn plating layer 105 is 0.1 g / m ² or more in terms of the amount of metal Sn. Moreover, although corrosion resistance improves, so that Sn content increases, if the amount of metal Sn exceeds 15 g / m < ² >, the corrosion-resistance improvement effect will be saturated. Therefore, from an economical viewpoint, the Sn content of the entire Sn plating layer 105 is set to 15 g / m ² or less in terms of the amount of metal Sn.
Sn content in the whole of the Sn-plated layer 105, more preferably, in terms of metal amount of Sn is 0.3 g / ^{m 2} or more 11g / ^{m 2} or less. By containing Sn of 0.3 g / m ² or more in terms of the amount of metal Sn, the above effect can be realized more reliably. Moreover, it becomes possible to further reduce the manufacturing cost of the Sn plating layer 105 by converting the Sn content of the entire Sn plating layer 105 to 11 g / m ² or less in terms of the amount of metal Sn.

[About the metal Ni plating layer 107]
On the surface of the Sn plating layer 105, as schematically shown in FIGS. 1A and 1B, a metal Ni plating layer 107 containing Ni as a main component is formed. The metallic Ni plating layer 107 is formed so as to cover the Sn plating layer 105 along the surface shape of the Sn plating layer 105. Therefore, the surface shape of the formed metal Ni plating layer 107 reflects the surface shape of the Sn plating layer 105.

  As shown in FIG. 3, when the metal Ni plating layer 107 is not provided on the Sn plating layer 105, oxygen present in the atmosphere permeates the chemical conversion treatment film layer 109 on the order of several hours, and oxygen Reaches the interface between the Sn plating layer 105 and the chemical conversion coating layer 109. As a result, oxygen and Sn in the Sn plating layer 105 react to form an Sn oxide layer 121 made of Sn oxide (SnOx) at the interface between the Sn plating layer 105 and the chemical conversion treatment film layer 109. Since the Sn oxide layer 121 is fragile, when the Sn oxide layer 121 is formed thick, the Sn oxide layer 121 is peeled off and the film adhesion is deteriorated.

On the other hand, oxygen penetrates to the surface of the Sn plating layer 105 by forming the metal Ni plating layer 107 on the Sn plating layer 105 as in the container steel plate 10 according to the present embodiment shown in FIGS. 1A to 2B. This can be prevented. As a result, contact between oxygen and Sn in the Sn plating layer 105 can be prevented, so that generation of oxidized Sn can be suppressed. As a result, in the steel plate for containers 10 according to the present embodiment, film adhesion can be improved.
Moreover, Ni which comprises the metal Ni plating layer 107 not only improves adhesiveness but is also excellent in weldability. Therefore, by forming the metal Ni plating layer 107, the weldability of the container steel plate 10 can be improved.

In order to ensure the above effects, the Ni content needs to be 1 mg / m ² or more in terms of the amount of metallic Ni. In addition, as the Ni content increases, the adhesion and weldability improve. However, when the Ni content exceeds 2000 mg / m ² in terms of metal Ni, the adhesion and weldability are saturated. Therefore, the Ni content is set to 2000 mg / m ² or less in terms of metal Ni from an economical viewpoint.
The Ni content in the metal Ni plating layer 107 is more preferably 5 mg / m ² or more, and still more preferably 80 mg / m ² or more, in terms of the amount of metal Ni. By containing Ni in the above range, it becomes possible to improve the adhesion and weldability more reliably. Further, the Ni content in the metal Ni plating layer 107 is more preferably 1500 mg / m ² or less, still 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 adhesion and weldability while suppressing costs.

The production amount of the Sn oxide layer 121 shown in FIG. 3 can be specified by a known method. However, by using the method shown in FIGS. 4A and 4B, the amount of Sn oxide layer 121 generated can be easily specified.
The method illustrated in FIGS. 4A and 4B is a method of specifying the amount of Sn oxide layer 121 generated using electrolytic treatment. In this method, the steel plate for containers 10 in a state where the Sn plating layer 105, the metallic Ni plating layer 107, and the chemical conversion treatment film layer 109 described later are formed on the steel plate 103 is used as a test piece.

More specifically, as shown in FIG. 4A, a predetermined electrolytic solution (for example, 0.01% by mass HBr aqueous solution) is injected into the electrolytic cell using an electrolytic cell divided into two regions by a glass filter. To do. In addition, a Pt electrode is provided as an anode in one area of the electrolytic cell, and a reference electrode (for example, AgCl reference electrode) and a test piece electrode as a cathode are provided in the other area. .
Thereafter, cathodic electrolysis is performed using a potentiostat under 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 this cathodic electrolysis treatment, as shown in FIG. 4B, electrolysis time and potential are measured. After charting these two measurement results, using the value obtained from the chart, the amount of Sn oxide layer 121 produced is determined by the amount of electricity per unit area required for reduction (electrolysis) (unit: mC / cm ² ).

Now, assuming that the production amount of the Sn oxide layer 121 is X (mC / cm ² ), the production amount X can be calculated by the following equation (1).

  Further, the time T required to completely remove the Sn oxide layer 121 can be calculated based on the following formula (2) using, for example, a time-potential curve chart schematically shown in FIG. 4B. it can.

Here, the chart length L can be obtained as follows.
That is, as shown in FIG. 4B, in the time-potential curve when the potential is taken on the horizontal axis and the time is taken on the vertical axis, the tangent line extending in the direction of the potential axis and the time axis extending in the direction of the time axis are drawn. And the intersection of these two tangents. Thereafter, the length of the perpendicular drawn from the obtained intersection to the potential axis is measured. The length of the perpendicular obtained by such processing is the chart length L.
Therefore, the time T required to completely remove the Sn oxide layer 121 is calculated from the above equation (2) using the electrolysis conditions and the chart length L obtained from the electrolysis results. Using the time T and the electrolysis conditions, the generation amount X of the Sn oxide layer 121 can be calculated based on the above formula (1).

In the container steel plate 10 according to the present embodiment, when the amount of Sn oxide layer 121 generated is expressed as the amount of electricity required for reduction, it is preferably 8 mC / cm ² or less. When the production amount of the Sn oxide layer 121 is expressed as the amount of electricity required for the reduction, in the case where it is 8 mC / cm ² or less, the Sn steel layer 121 is not peeled off. Have
In addition, the lower limit of the production amount of the Sn oxide layer 121 is not particularly limited, and as is clear from the above description, the production amount of the Sn oxide layer 121 is preferably as small as possible.

[Chemical conversion treatment film layer 109]
On the metal Ni plating layer 107, a chemical conversion treatment film layer 109 is formed as schematically shown in FIGS. 1A and 1B. Chemical conversion coating layer 109 contains at least a Zr compound of 0.01~150mg / ^{m 2} of metal Zr content, the phosphate compound of 0.01~80mg / ^{m 2} in the amount of P, and mainly Zr compound And a composite coating layer.
In the present embodiment, the composite coating layer represents a coating layer that is present in a partially mixed state without completely mixing the Zr compound and the phosphate compound.
When a phosphoric acid film having a phosphoric acid compound is formed on a Zr film having a Zr compound, some effects can be obtained with respect to corrosion resistance and adhesion, but this is not sufficient in practice. However, since the Zr compound and the phosphoric acid compound are present in a partially mixed state in the chemical conversion coating layer 109 as in the chemical conversion coating layer 109 according to the present embodiment, excellent corrosion resistance and adhesion Sex can be obtained.

  The Zr compound contained in the chemical conversion coating layer 109 according to this embodiment has a function of improving corrosion resistance, adhesion, and processing adhesion. Examples of the Zr compound according to this embodiment include Zr oxide, Zr phosphate, Zr hydroxide, Zr fluoride, and the like, and the chemical conversion film layer 109 contains a plurality of the above Zr compounds. Since such a Zr compound is excellent in corrosion resistance and adhesion, the corrosion resistance and adhesion of the steel plate 10 for containers improve as the amount of the Zr compound contained in the chemical conversion coating layer 109 increases.

Specifically, when the content of the Zr compound in the chemical conversion coating layer 109 is 0.01 mg / m ² or more in terms of the amount of metal Zr, a coating agent is applied on the chemical conversion coating layer 109. Adhesiveness and corrosion resistance with a practically suitable coating agent are ensured. On the other hand, as the Zr compound content increases, the adhesion with the coating agent and the corrosion resistance also improve. However, when the Zr compound content exceeds 150 mg / m ² in terms of metal Zr content, Adhesion and corrosion resistance are saturated. Therefore, in the steel plate for containers 10 according to the present embodiment, from an economical viewpoint, the content of the Zr compound (that is, the content of Zr) is 0.01 mg / m ^{2 to} 150 mg in terms of the amount of metal Zr. / M ² .

The content of the Zr compound is preferably 0.05 mg / m ² or more and 120 mg / m ² or less in terms of metal Zr content. By converting the content of the Zr compound to 0.05 mg / m ² or more and 120 mg / m ² or less in terms of the amount of metal Zr, more suitable corrosion resistance and adhesion such as coating can be obtained, and also economically preferable.

The chemical conversion treatment film layer 109 further includes one or more phosphate compounds in addition to the Zr compound described above.
The phosphoric acid compound according to the present embodiment has a function of improving corrosion resistance, adhesion, and processing adhesion. As an example of the phosphoric acid compound according to the present embodiment, phosphoric acid formed by a reaction between a phosphoric acid ion and a compound contained in the steel plate 103, the Sn plating layer 105, the metal Ni plating layer 107, and the chemical conversion coating layer 109. Fe, phosphoric acid Sn, phosphoric acid Ni, phosphoric acid Zr, etc. are mentioned. The chemical conversion film layer 109 contains at least one phosphoric acid compound described above.
Since the phosphoric acid compound is excellent in corrosion resistance and adhesion, the corrosion resistance and adhesion of the steel plate 10 for containers improve as the amount of the phosphoric acid compound increases.

Specifically, in consideration of the content of the Zr compound, if the content of the phosphate compound in the chemical conversion coating layer 109 is 0.01 mg / m ² or more in terms of P amount, a practically suitable coating agent Adhesion and corrosion resistance can be obtained. On the other hand, as the content of the phosphoric acid compound increases, the adhesion with the coating agent and the corrosion resistance also improve, but when the content of the phosphoric acid compound exceeds 80 mg / m ² in terms of P amount, The adhesion and corrosion resistance are saturated. Accordingly, the container steel sheet 10 according to this embodiment, the content of the phosphate compound, and 0.01mg ^{/ m 2} ~80mg ^/ m 2 in terms of P content.
The content of the phosphoric acid compound is preferably 0.05 mg / m ² or more and 60 mg / m ² or less in terms of P amount. By making content of a phosphoric acid compound into said range, adhesiveness and corrosion resistance with a more excellent coating agent can be obtained, and it is economically preferable.

  The configuration of the container steel plate 10 according to the present embodiment has been described in detail above with reference to FIGS. 1A to 4B.

As shown in FIG. 5, the container according to the present embodiment is obtained by applying a coating agent according to the application to the outermost surface of the container steel plate 10 according to the present embodiment (that is, the surface of the chemical conversion coating layer 109). The coating layer 151 can be formed on the outermost surface of the steel plate 10 for use. The coating layer 151 is applied with a treatment liquid on the chemical conversion coating layer 109, and then is subjected to heat treatment to reach a temperature of about 210 ° C. when a coating film is formed and about 160 ° C. when a film is laminated. Is formed.
When the heat treatment is performed so as to reach the above reached temperature, at least a part of the Sn plating layer 105 is melted. As a result, Sn forming the Sn plating layer 105 and Ni forming the metal Ni plating layer 107 react to form an alloy, and the interface between the Sn plating layer 105 and the metal Ni plating layer 107 as shown in FIG. Thus, the Ni—Sn alloy layer 153 is formed. Since the Ni—Sn alloy layer 153 is excellent in corrosion resistance, the corrosion resistance of the steel plate 10 for containers is further improved by further forming the coating layer 151 on the chemical conversion treatment film layer 109.

<About measuring method of component content>
Here, the amount of metallic Sn in the Sn plating layer 105 and the amount of metallic Ni in the metal Ni plating layer 107 can be measured by, for example, a fluorescent X-ray method. In this case, a calibration curve related to the amount of metal Sn is specified in advance using an Sn adhesion amount sample with a known amount of metal Sn, and the amount of metal Sn is specified relatively using the calibration curve. Similarly, a calibration curve related to the amount of metal Ni is specified in advance using a sample of the amount of deposited nickel with a known amount of metal Ni, and the amount of metal Ni is relatively specified using the calibration curve.
Further, the amount of metal Zr and the amount of P in the chemical conversion coating layer 109 can be measured by a quantitative analysis method such as fluorescent X-ray analysis, for example. Further, what kind of compound is present in the chemical conversion treatment film layer 109 can be specified by performing analysis by X-ray photoelectron spectroscopy (XPS). .
In addition, the measuring method of each component amount is not limited to said method, It is possible to apply another well-known measuring method.

<About the manufacturing method of the steel plate 10 for containers>
Next, the manufacturing method of the steel plate 10 for containers which concerns on this embodiment is demonstrated in detail, referring FIG. FIG. 6 is a flowchart for explaining an example of the flow of the manufacturing method of the container steel plate 10 according to this embodiment.

  In the method for manufacturing the container steel plate 10 according to the present embodiment, first, a known pretreatment is performed on the steel plate 103 as necessary (step S101).

[Sn plating layer forming step]
Thereafter, the Sn plating layer 105 is formed on the surface of the steel plate 103 (step S103).
The method for forming the Sn plating layer 105 is not particularly limited, but for example, a known electroplating method is preferably used, and a method of immersing and plating the steel plate 103 in molten Sn may be used.
In addition, after forming Sn plating layer 105, in order to form Fe-Sn alloy layer 105b, you may perform a molten tin process. The molten tin treatment can be performed by performing a Sn plating process on the steel sheet 103, setting the ultimate temperature to 200 ° C. or higher, performing a heat treatment, once melting the formed Sn plating, and then rapidly cooling it. it can. By this molten tin treatment, Sn in the Sn plating layer 105 located on the steel plate 103 side is alloyed with Fe in the steel plate to form the Fe—Sn alloy layer 105b.

[Metal Ni plating layer forming process]
After forming the Sn plating layer 105, the metal Ni plating layer 107 is formed (step S105).
The metal Ni plating layer 107 can be formed by a known plating process using a Ni plating bath containing Ni ions. The Ni plating bath of this embodiment contains 10 g / L or more of sulfate ions and 30 g / L or more of Ni ions.

In the case where the Ni plating bath does not contain Cl ions, it is more 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 sulfate ions to 75 g / L or more and the concentration of Ni ions to 40 g / L or more, the Ni content in the metal Ni plating layer 107 can be set within a suitable range.
In addition, by setting the concentration of sulfate ions to 90 g / L or less and the concentration of Ni ions to 55 g / L or less, the Ni content in the metal Ni plating layer 107 can be in a suitable range, economically. Is also preferable.

The Ni plating bath may further contain Cl ions. When the Ni plating bath contains Cl ions, the Ni plating bath preferably contains 20 to 40 g / L of sulfate ions, 40 to 55 g / L of Ni ions, and 35 to 45 g / L of Cl ions. By setting the concentration of sulfate ions to 20 g / L or more, the concentration of Ni ions to 40 g / L or more, and the concentration of Cl ions to 35 g / L or more, the Ni content in the metal Ni plating layer 107 is in a suitable range. Is possible.
In addition, the Ni content in the metal Ni plating layer 107 is preferable by setting the sulfate ion concentration to 40 g / L or less, the Ni ion concentration to 55 g / L or less, and the hydrochloric acid ion concentration to 45 g / L or less. Therefore, it is economically preferable.

  The Ni plating bath may further contain 30 g / L or more of borate ions. By adding borate ions to the Ni plating bath, it is possible to suppress an increase in pH of the Ni plating bath accompanying the plating treatment. The borate ion content is more preferably 40 g / L or more and 50 g / L or less. By setting the borate ion content to 40 g / L or more, it is possible to more reliably suppress the pH increase of the Ni plating bath. Moreover, by setting the borate ion content to 50 g / L or less, an increase in pH of the Ni plating bath can be suppressed, which is also economically preferable.

[Chemical conversion coating layer formation process]
Subsequently, a chemical conversion treatment film layer 109 is formed on the metal Ni plating layer 107 by performing cathodic electrolysis treatment or immersion treatment (step S107).

The chemical conversion bath used for cathodic electrolysis treatment or immersion treatment is 10 ppm to 20000 ppm of Zr ions, 10 ppm to 20000 ppm of F ions, 10 ppm to 3000 ppm of phosphate ions, and a total of 100 ppm to 30000 ppm of nitrate ions. And sulfate ions.
When the addition amount of F ions is less than 10 ppm, F that forms a complex with Zr ions decreases, and Zr does not adhere, which is not preferable. In addition, when the amount of F ions added exceeds 20000 ppm, Zr adheres excessively, which is not preferable.

If the amount of nitrate ion added is less than 100 ppm, the amount of nitric acid that increases the deposition efficiency of Zr ions decreases, and the amount of Zr deposition decreases, which is not preferable. Further, when the amount of nitrate ion added is more than 30000 ppm, Zr adheres excessively, which is not preferable.
If the amount of sulfate ion added is less than 100 ppm, the amount of sulfuric acid that increases the adhesion efficiency of Zr ions decreases, and the amount of Zr adhesion decreases, which is not preferable. Further, when the amount of sulfate ion added is more than 30000 ppm, Zr adheres excessively, which is not preferable.
The nitrate ions and sulfate ions may be contained in the chemical conversion bath in a total amount of both 100 ppm and 30000 ppm, and both ions of nitrate ions and sulfate ions may be contained in the chemical conversion bath. Only one of sulfate ion and sulfate ion may be contained in the chemical conversion bath.

The chemical conversion bath is preferably 50 ppm or more and 17000 ppm or less of Zr ions, 50 ppm or more and 17000 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 27000 ppm or less of nitrate ions and sulfate ions, It is preferable to contain.
By making the addition amount of Zr ions 50 ppm or more, it becomes possible to more reliably prevent a decrease in the adhesion amount of Zr. Moreover, the cloudiness of the chemical conversion treatment film accompanying precipitation of a phosphate can be prevented more reliably by making the addition amount of F ion 50 ppm or more. Similarly, by making the addition amount of phosphate ions 50 ppm or more, the cloudiness of the chemical conversion film accompanying precipitation of phosphate can be more reliably prevented. Moreover, the fall of the adhesion efficiency of a chemical conversion treatment film can be prevented more reliably by making the total addition amount of a nitrate ion and a sulfate ion into 300 ppm or more. In addition, the manufacturing cost of the chemical conversion treatment film layer 109 can be more reliably reduced by setting the upper limit value of each additive component as described above.

A phenol resin or the like may be further added to the chemical conversion bath. When the phenol resin is added to the chemical conversion bath, the phenol resin may be modified with amino alcohol to make it water-soluble.
Further, tannic acid may be further added to the chemical conversion bath. By adding tannic acid to the chemical conversion treatment bath, the tannic acid reacts with Fe in the steel sheet 103 to form a film of Fe tannic acid on the surface of the steel sheet 103. This film of Fe tannate is preferable because it improves rust resistance and adhesion.

The pH of the chemical conversion bath is preferably 3.1 to 3.7, more preferably around 3.5. In order to adjust the pH, nitric acid or ammonia or the like may be added to the chemical conversion bath.
Moreover, it is preferable that the temperature of a chemical conversion treatment bath shall be 5 degreeC or more and less than 90 degreeC. When the temperature of the chemical conversion treatment bath is less than 5 ° C., the formation efficiency of the chemical conversion treatment film layer 109 is poor and not economical, which is not preferable. Further, when the temperature of the chemical conversion treatment bath is 90 ° C. or higher, the structure of the chemical conversion treatment film layer 109 is non-uniform, and defects, cracks, microcracks, etc. occur, and that part becomes a starting point for corrosion or the like. Therefore, it is not preferable.

When the chemical conversion treatment film layer 109 is formed by electric field treatment (cathodic electrolysis treatment) using a chemical conversion treatment bath, a current density of 0.5 A / dm ² or more and 20 A / dm ² or less is used for 0.05 seconds to 10 seconds. It is preferable to carry out the following cathodic electrolytic treatment time.
When the current density is less than 0.5 A / dm ² , the adhesion amount of the chemical conversion treatment film layer 109 is lowered, and the cathode electrolysis treatment time is lengthened and the productivity is lowered. In addition, when the current density exceeds 20 A / dm ² , the amount of the chemical conversion treatment film layer 109 is excessive, and in some cases, the chemical conversion treatment film layer 109 is insufficiently adhered in the cleaning step after the chemical conversion treatment. Is not preferred because it is washed away (peeled).
When the cathodic electrolysis time is less than 0.05 seconds, the amount of the chemical conversion treatment film layer 109 is decreased, and the corrosion resistance and adhesion such as coating are decreased. When the cathodic electrolysis time exceeds 10 seconds, the amount of the chemical conversion treatment film layer 109 is excessive, and the chemical conversion treatment layer 109 with insufficient adhesion is washed away (peeled) in the cleaning step after the chemical conversion treatment. Therefore, it is not preferable.

  When the chemical conversion treatment film layer 109 is formed by immersion treatment using the chemical conversion treatment bath, the immersion treatment time for 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 seconds, the adhesion amount of the chemical conversion treatment film layer 109 is reduced, and the immersion treatment time is increased and the productivity is lowered. In addition, when the immersion treatment time exceeds 100 seconds, the amount of the chemical conversion treatment film layer 109 is excessive, and in some cases, the chemical conversion treatment film layer 109 that is insufficiently adhered in the washing step after the immersion treatment is washed away. It is not preferable because it is peeled off (peeled).

  Moreover, as a solvent of the chemical conversion treatment bath used for formation of the chemical conversion treatment film layer 109 concerning this embodiment, deionized water, distilled water, etc. can be used, for example. Further, when the chemical conversion film layer 109 is formed by cathodic electrolysis, it is preferable to consider the electric conductivity of the solvent, but the preferable electric conductivity of the solvent is 10 μS / cm or less, more preferably 5 μS / cm. Hereinafter, it is more preferably 3 μS / cm or less. However, the solvent of the chemical conversion treatment bath is not limited thereto, and can be appropriately selected according to the material to be dissolved, the formation method, the formation conditions of the chemical conversion treatment film layer 109, and the like. However, it is preferable to use deionized water or distilled water from the viewpoints of industrial productivity, cost, and environment based on the stable adhesion amount of each component.

In the chemical conversion treatment bath used for forming the chemical conversion treatment film layer 109 according to the present embodiment, for example, a Zr complex such as H ₂ ZrF ₆ can be used as a Zr supply source. Zr in the Zr complex becomes Zr ^{4+ in the} hydrolysis reaction and exists in the chemical conversion solution. Such Zr ions react rapidly in the chemical conversion treatment bath to form compounds such as ZrO ₂ and Zr ₃ (PO ₄ ) ₄ , and by a dehydration condensation reaction with a hydroxyl group (—OH) present on the metal surface. A Zr film can be formed.

Thereafter, if necessary, a known post-treatment is performed on the steel plate 103 on which the Sn plating layer 105, the metal Ni plating layer 107, and the chemical conversion treatment film layer 109 are formed (step S109).
By performing the processing in such a flow, the container steel plate 10 according to the present embodiment is manufactured.

  Below, the manufacturing method of the steel plate for containers and the steel plate for containers concerning this embodiment is demonstrated concretely, showing an Example. In addition, the Example shown below is an example of the manufacturing method of the steel plate for containers and the steel plate for containers concerning this embodiment, Comprising: The manufacturing method of the steel plate for containers and the steel plate for containers concerning this embodiment is the following example. Not limited to

[Example 1]
Film adhesion was examined using a steel plate for containers in which a Sn plating layer, a metallic Ni plating layer and a chemical conversion coating layer were formed on a steel plate as a test material. Table 1 shows the Sn plating content, Ni plating content, Zr compound content, and phosphoric acid compound content of each Example and Comparative Example. As shown in Table 1, in some examples and comparative examples, the molten tin treatment was performed after the Sn plating layer was formed. In addition, the adhesion amount of each plating layer was measured by the fluorescent X-ray method.

[Measurement of film adhesion]
A PET film 160 having a thickness of 20 μm was laminated on the steel plate for containers 10 on one side of each test material. Then, it punched into the can bottom type | mold as shown in FIG. 7, and performed the retort process for 30 minutes at the temperature of 125 degreeC using the high pressure steam sterilizer.
The state of peeling of the PET film 160 was observed, and was evaluated in four stages based on the ratio of the area of the peeling portion to the entire surface area of the inside of the bottom of the PET film 160 (the side in contact with the can contents). The evaluation criteria for film adhesion are as shown below.
In addition, when each test material after a retort process was observed by XRD, it was confirmed that the Ni-Sn alloy layer is formed.

[Evaluation criteria for film adhesion]
Very Good: Peeling area ratio: 0% to 10%
Good: Peeling area ratio: more than 10% and not more than 20% Poor: Peeling area ratio: more than 20% and not more than 50% Bad: Peeling area ratio: more than 50%

  From Table 1, it was revealed that the examples have excellent film adhesion. Moreover, all the comparative examples were inferior in film adhesiveness.

[Example 2]
Ni plating was performed on the plated steel sheet on which the Sn plating layer was formed using a Ni plating bath containing the components shown in Table 2. Table 2 shows the Ni content of the formed metal Ni plating layer.
With respect to the plated steel sheet on which the Sn plating layer and the metal Ni plating layer were formed, a chemical conversion treatment film layer having each component shown in Table 3 was used, and a chemical conversion treatment film layer was formed by immersion treatment or cathodic electrolysis treatment.
Table 4 shows the contents of the Zr compound and the phosphate compound in the formed chemical conversion coating layer. Further, the amount of Sn oxide layer produced was measured by the method shown in FIGS. 4A and 4B. The measurement results are shown in Table 4.
Film adhesion was evaluated in the same manner as in Example 1, using a steel plate for containers in which a Sn plating layer, a metallic Ni plating layer, and a chemical conversion coating layer were formed on a steel plate as a test piece. The evaluation results are shown in Table 4.

  As is clear from Table 4, it was revealed that all of the examples according to the present embodiment have suitable film adhesion. On the other hand, it became clear that the comparative example was inferior in film adhesion.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention belongs can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  According to the said one embodiment, the manufacturing method of the steel plate for containers which has the outstanding film adhesiveness, and the steel plate for containers can be provided.

DESCRIPTION OF SYMBOLS 10 Steel plate for containers 101 Plated steel plate 103 Steel plate 105 Sn plating layer 105a Sn layer 105b Fe-Sn alloy layer 107 Metal Ni plating layer 109 Chemical conversion coating layer 121 Sn oxide layer 151 Coating layer 153 Ni-Sn alloy layer

Claims (7)

With steel plate;
As an upper layer of the steel sheet, an Sn plating layer containing 0.1 to 15 g / m ² of Sn or Fe—Sn alloy in terms of the amount of metal Sn;
As a top layer of the Sn plating layer, a metal Ni plating layer containing 1 to 2000 mg / m ² of Ni in terms of the amount of metal Ni;
As an upper layer of the metal Ni plating layer, 0.01 to 150 mg / m ² of Zr compound in terms of metal Zr amount, and 0.01 to 80 mg / m ² of phosphate compound in terms of P amount, Containing a chemical conversion coating layer;
A steel plate for containers, comprising: ^2. The steel plate for containers according to claim 1, wherein the Sn plating layer contains 0.3 to 11 g / m ² of Sn or Fe—Sn alloy in terms of the amount of metal Sn. 3. The steel plate for containers according to claim 1, wherein the metal Ni plating layer contains 5 to 1500 mg / m ² of Ni in terms of the amount of metal Ni. The said chemical conversion treatment film layer is 0.05-120 mg / m < ² > of said Zr compound in conversion to metal Zr amount, The container for any one of Claims 1-3 characterized by the above-mentioned. steel sheet. The said chemical conversion treatment film layer contains 0.05-60 mg / m < ² > of the said phosphoric acid compound in conversion of P amount, The container for any one of Claims 1-4 characterized by the above-mentioned. steel sheet. The Sn oxide layer containing the oxidation Sn whose electric quantity required for reduction | restoration is 8 mC / cm < ² > or less is further provided between the said Sn plating layer and the said metal Ni plating layer, The 1-5 characterized by the above-mentioned. The steel plate for containers according to any one of the above. An Sn plating layer forming step of forming an Sn plating layer containing 0.1 to 15 g / m ^{2 of} Sn in the amount of metal Sn on the steel sheet;
A metal Ni plating layer that forms a metal Ni plating layer on the Sn plating layer using a Ni plating bath containing 10 g / L or more of sulfate ions and 30 g / L or more of Ni ions after the Sn plating layer forming step. A forming step;
After the metal Ni plating layer forming step, it 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 to 30000 ppm of nitrate ions and sulfate ions, and the temperature is 5 to 90 Using a chemical conversion treatment bath at a temperature of 0.5 to 20 A / dm ² and a cathodic electrolysis treatment carried out at a cathodic electrolysis time of 0.05 to 10 seconds or an immersion treatment time of 0.2 to 100 seconds A chemical conversion treatment film layer forming step of forming a chemical conversion treatment film layer on the metal Ni plating layer by performing an immersion treatment;
The manufacturing method of the steel plate for containers characterized by having.

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