JP6590651B2 - Surface-treated steel sheet, method for producing the same, and container using the surface-treated steel sheet - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a surface-treated steel sheet obtained by coating an organic resin layer on nickel plating and tin plating, and in particular, an organic resin-coated steel sheet excellent in corrosion resistance while suppressing elution of nickel even in an acidic aqueous solution, and a method for producing the same. The present invention relates to a container such as a metal can using a resin-coated steel plate.

In containers for food and beverage cans such as beverages and foods, tinplate has been conventionally used as a base material. Today, tincture is widely used in various food cans including tuna cans because of its excellent corrosion resistance.
When manufacturing a container using this tinplate, the corrosion resistance improves as the coating amount of tin (hereinafter also referred to as “Sn”) increases. LTS (Lightly Tin Steel), which has been reduced and replaced with metallic chrome, etc. is on the market.

However, since this LTS has a relatively small amount of Sn, the corrosion resistance is generally worse than that of tinplate. On the other hand, a technique has been proposed in which corrosion resistance is improved by combining nickel (Ni) plating and Sn plating, and further, adhesion to an organic resin coated thereon is improved. .
For example, according to Patent Document 1, in order to improve the adhesion and corrosion resistance of a nickel-plated steel sheet, a surface-treated steel sheet in which tin plating is performed after non-uniform island-shaped nickel plating is proposed.
Furthermore, according to Patent Document 2, in order to overcome the problem that the conventional nickel-plated steel sheet does not have sufficient adhesion to the organic coating resin layer, fine particles having an uneven shape made of nickel are formed by a dilute nickel plating bath. Thus, a technique for realizing a surface-treated steel sheet excellent in work adhesion with an organic coating resin has been proposed.

Japanese Patent Publication No. 2-14438 JP 2013-245394 A

In patent document 1 and patent document 2 mentioned above, adhesiveness with coating resin improves to some extent by exhibiting an anchor effect using island-like nickel plating or fine granular nickel plating.
However, when the surface-treated steel sheet with Ni plating as described above is immersed in an acidic aqueous solution, Ni may be eluted. For example, fruit cans and jam cans are acidic in nature, and sweet corn and other foods contain antioxidants and pH adjusters, so many food can containers contain an acidic liquid. I can say that.
In recent years, attention to metal allergy has been particularly increased, and therefore, there has been a demand for the appearance of a material that reduces the main elution amount of Ni as a cause of this metal allergy.

  The present invention has been made in view of solving such problems, and is a surface-treated steel sheet and organic resin-coated steel sheet that have improved corrosion resistance while suppressing the elution amount of Ni, a method for producing these, and this organic An object is to provide a container using a resin-coated steel sheet.

In order to solve the above problems, a surface-treated steel sheet according to an embodiment of the present invention is (1) a surface-treated steel sheet on which Ni plating and Sn plating are formed, and is formed on the steel sheet and the steel sheet. It has a Ni plating layer, an alloy layer formed on the Ni plating layer, and a Sn plating layer formed on the alloy layer, and the alloy layer includes a Ni—Sn alloy layer and a Ni—Sn—Fe alloy layer. The Sn alloying rate is 20% or more and 90% or less with respect to the plating amount of the Sn plating layer, and the total Ni plating amount in the film of the surface-treated steel sheet is 0.01 g / m ² to 2.0 g / m ² , the total Sn plating amount is 0.4 g / m ² to 2.0 g / m ² , and the atomic ratio Ni / Sn between Ni and Sn after tin removal is 0.05 or more. It is 5.0 or less.

Here, the “film of the surface-treated steel sheet” refers to a film formed on the surface-treated steel sheet before the coating layer or organic resin layer described later, and includes, for example, the above-described Ni plated layer, Sn plated layer, and alloy layer. It is. The “total Ni plating amount” refers to the total amount of Ni contained in the film of the surface-treated steel sheet. The “total Sn plating amount” refers to the total amount of Sn contained in the film of the surface-treated steel sheet.
Furthermore, in the surface-treated steel sheet having the feature (1) described above, (2) a Ni—Fe alloy layer is further included, and from the steel sheet side, the Ni—Fe alloy layer, the Ni plating layer, the Ni— It is preferable that the Sn—Fe alloy layer or the Ni—Sn layer and the Sn plating layer are laminated in this order.

In the surface-treated steel sheet having the above-described feature (1) or (2) , ( 3 ) the Ni plating layer is preferably granular Ni particles.
Further, in the surface-treated steel sheet having any one of the features (1) to ( 3 ) described above, ( 4 ) at least one oxide of Zr, Ti, and Al is formed on at least one surface of the surface-treated steel sheet. It is preferable that a coating layer containing be formed.
In the surface-treated steel sheet having the characteristics described in ( 4 ), ( 5 ) it is preferable that the coating layer contains an oxide of P (phosphorus).
Moreover, in order to solve the said subject, the organic resin layer coat | covers the organic resin coated steel plate concerning one Embodiment of this invention on the surface-treated steel plate in any one of above-mentioned (1)-( 5 ). It is characterized by.
Moreover, in order to solve the said subject, the container concerning one Embodiment of this invention consists of an above described organic resin coating steel plate. Examples of the container include a metal can, a lid, or a metal case that stores beverages, food, medicines, and the like.

Moreover, in order to solve the said subject, the manufacturing method of the surface treatment steel plate concerning one Embodiment of this invention is a manufacturing method of the surface treatment steel plate in which the Ni plating layer and the Sn plating layer were formed, Comprising: A step of forming a Ni plating layer, a step of forming a Sn plating layer on the Ni plating layer by performing Sn plating on the steel sheet on which the Ni plating layer is formed, and a formation of the Sn plating layer Then, the steel sheet is heated so that the ultimate temperature of the steel sheet is 180 to 240 ° C., whereby a Ni—Sn alloy layer , a Ni—Fe alloy layer , and a Ni—Sn—Fe layer are formed on the steel sheet. A step of forming at least one of the alloy layers , and a Sn alloying rate in the surface-treated steel sheet is 20% or more and 90% or less with respect to a plating amount of the Sn-plated layer, and the film of the surface-treated steel sheet In Total Ni plating weight of ^{0.01g / m 2 ~ 2.0g / m} 2, the total Sn plating weight of ^{0.4g / m 2 ~ 2.0g / m} 2, and a Ni after Datsusuzu that The atomic ratio Ni / Sn of Sn is 0.05 or more and 5.0 or less.
In the manufacturing method of the surface-treated steel sheet , the particle density is 500 particles / μm ^{2 to} 1000 particles / μm ² and the average particle diameter is 0.01 μm to 0.05 μm by the step of forming the Ni plating layer. granular Ni particles composed is formed it is preferable.

  According to the present invention, since the Ni plating layer, the Sn plating layer, and the alloy layer containing Ni and Sn are formed in an optimal state and ratio, it is excellent while reducing the amount of Ni elution even in an acidic aqueous solution. A surface-treated steel sheet having corrosion resistance can be realized.

It is sectional drawing which showed typically the structure of the surface treatment steel plate which concerns on this embodiment. It is process drawing which showed the manufacturing flow which manufactures the surface treatment steel plate, organic resin coated steel plate, and container which concern on this embodiment. It is sectional drawing which showed the steel plate in which the Ni plating layer 2 which concerns on this embodiment was formed. It is sectional drawing which showed the steel plate with which the Sn plating layer 4 was formed on the Ni plating layer 2 which concerns on this embodiment. It is sectional drawing which showed typically the structure of the surface treatment steel plate after reflow based on this embodiment. It is sectional drawing which showed typically the structure of the surface treatment steel plate in which the coating layer concerning this embodiment was formed. It is sectional drawing which showed typically the structure of the organic resin coating steel plate which concerns on this embodiment. It is sectional drawing regarding the container (seamless can) which concerns on this embodiment.

<Embodiment>
Hereinafter, an embodiment for carrying out the present invention will be described.
The surface-treated steel sheet according to the present embodiment includes at least a steel sheet as a base material and a surface treatment layer formed on the steel sheet. The surface treatment layer includes at least a Ni plating layer, an alloy layer on the Ni plating layer, and an Sn plating layer on the alloy layer.
Hereinafter, the individual elements of the surface-treated steel sheet according to the present embodiment will be described in detail with reference to the drawings as appropriate.

<Steel plate>
As the steel sheet as the base material of the surface-treated steel sheet, a metal plate such as iron or various alloys of about 0.1 mm to 0.5 mm is used. Examples of the metal plate include those subjected to various surface treatments such as tinplate, TFS, and nickel-plated steel plate.
As a steel plate suitable for the present embodiment, for example, a low carbon aluminum killed steel having a carbon content of 0.01 to 0.15% by mass generally used for cans can be used. Furthermore, non-aging ultra-low carbon aluminum killed steel having a carbon content of less than 0.01% by mass with addition of niobium or titanium is also applicable. These aluminum killed steel hot-rolled sheets are pickled with electrolytic pickling, etc. to remove surface scales, then cold-rolled, and then subjected to electrolytic cleaning, annealing, rolling, etc. It may be used as

<Surface treatment layer>
FIG. 1 is a cross-sectional view schematically showing the structure of the surface-treated steel sheet ST according to this embodiment, and more specifically, the above-described steel sheet 1 and the surface-treated layer are schematically shown. Among these, the surface treatment layer includes the Ni plating layer 2, the first alloy layer 3, and the Sn plating layer 4.

The Ni plating layer 2 is interposed between the steel plate 1 and the first alloy layer 3. In FIG. 1, the Ni plating layer 2 covers the entire upper surface of the steel plate 1, but is not particularly limited to this aspect, and at least a part of the upper surface of the Ni plating layer 2 is covered with the Ni plating layer 2. It does not have to be broken.
The first alloy layer 3 is interposed between the Ni plating layer 2 and the Sn plating layer 4. In the first alloy layer 3, part of Fe that is a component of the steel plate 1 is thermally diffused during heat treatment (for example, melt heat treatment described later), or a boundary portion between the Ni plating layer 2 and the Sn plating layer 4 is formed. It is formed by alloying. In the present embodiment, the first alloy layer 3 includes at least one of a Ni—Sn alloy and a Ni—Sn—Fe alloy. Further, when the first alloy layer 3 includes a Ni—Sn alloy, the Ni—Sn alloy preferably includes Ni ₃ Sn ₄ .
The Sn plating layer 4 is formed so as to cover the first alloy layer 3. In FIG. 1, the Sn plating layer 4 covers the entire upper surface of the first alloy layer 3, but is not particularly limited to this mode, and at least a part of the upper surface of the first alloy layer 3 is an Sn plating layer. 4 may not be covered.

<Surface treated steel plate>
The surface-treated steel sheet ST shown in FIG. 1 is manufactured, for example, in the following manner. That is, in the present embodiment, a surface-treated steel sheet ST is manufactured in which Ni plating is first deposited, Sn plating is further deposited thereon, and then the elution amount of Ni is reduced through the subsequent melt heat treatment. .
In addition, in this embodiment, the precipitation form of Ni plating is not specifically limited, However, The thing which precipitated Ni plating in a granular form is especially preferable. As conditions for depositing Ni plating in a granular form, for example, the components of the plating solution are nickel sulfate 10 to 100 g / L, more preferably 40 to 80 g / L, ammonium sulfate 10 to 100 g / L, more preferably 20 to 80 g / L. Citric acid is 5 to 100 g / L, more preferably 10 to 20 g / L. The pH is 2.0 to 5.0, more preferably 3.5 to 4.5. Moreover, as conditions in cathode electrolysis, it is preferable that the current density is 30 to 100 A / dm ² , more preferably 30 to 50 A / dm ² . In addition to the above deposition conditions, a Ni plating layer obtained from a Watt bath can be applied to this embodiment. As a component of such a watt bath, nickel sulfate 200 g / L to 1000 g / L, more preferably 200 g / L to 300 g / L, nickel chloride 10 g / L to 100 g / L, more preferably 30 g / L to 80 g / L. L, boric acid is 10 g / L to 100 g / L, more preferably 20 g / L to 60 g / L. Moreover, as a value of pH, it is pH2.0-pH5.0, More preferably, it is pH3.5-pH4.5. The conditions for cathodic electrolysis are a current density of 1 A / dm ^{2 to} 10 A / dm ² , more preferably 2 A / dm ^{2 to} 8 A / dm ² .
Hereinafter, a specific manufacturing process of the surface-treated steel sheet ST will be described in order with reference to FIG. In the following description, an example in which the surface treatment layer of the present embodiment is formed on at least one surface side of the steel plate 1 is shown, but the present invention is not limited to this aspect, and may be formed on the other surface of the steel plate 1. .

First, the Ni plating layer 2 described above is formed on the steel plate 1 by a plating process (step 1).
In the present embodiment, as shown in FIG. 3, the Ni plating layer 2 has a granular appearance on the steel plate 1. It is not essential that the Ni plating layer 2 is granular, but the surface area is increased by precipitating Ni as granular, thereby promoting the formation of a Ni—Sn alloy during reflow (melting and heating) treatment described later. It is preferable at the point which can do. Moreover, if the Ni plating layer 2 is granular, the formation of an alloy layer of Fe and Ni that is a component of the steel plate 1 is suppressed.
At this time, the Ni plating amount (total Ni plating amount in the film of the surface-treated steel sheet) is 0.01 g / m ^{2 to} 2.0 g / m ² , preferably 0.01 g / m ^{2 to} 1.0 g / m ^2. , more preferably plated as ^{0.01g / m 2 ~0.5g / m 2} , and more preferably a 0.01g ^{/ m 2} ~0.1g ^/ m 2 processing is performed. When the Ni plating amount is less than 0.01 g / m ² , the deposited Ni plating amount is not sufficient, and for example, sufficient adhesion cannot be ensured. On the other hand, when the amount of Ni plating exceeds 2.0 g / m ² , the adhesion due to the expression of the anchor effect is sufficient, but it is not preferable because the cost increases.

Here, the fact that the Ni plating layer 2 is “granular” means that the Ni plating layer 2 has the following characteristic values at the same time.
[Particle density]
First, as the first characteristic value, a value of particle density is given.
That is, the particle density of the granular Ni plating layer 2 in the present embodiment is 500 / μm ^{2 to} 1000 / μm ² . When the particle density is less than 500 particles / μm ² , the nickel particles are too fine, the plating surface shape is too flat, and for example, sufficient adhesion with the organic resin layer cannot be obtained. On the other hand, when the particle density exceeds 1000 particles / μm ² , the plating surface shape is too smooth and sufficient adhesion to the organic resin layer cannot be obtained.
As will be described later, elution of Ni in the acidic solution can be suppressed by performing heat treatment by combining the granular Ni plating layer 2 and the Sn plating layer 3. Furthermore, since a surface-treated steel sheet having irregularities on the surface can be obtained, excellent adhesion can be obtained even when an organic resin-coated steel sheet is processed.

The “particle density” refers to the range of 1 × 1 μm (that is, 1 μm ² ) when the surface of the surface treatment film 2 is observed with a scanning electron microscope (SEM) and the average particle diameter of the particles is about 0.5 μm or less. The number of nickel particles per unit area is measured and obtained by counting the number of particles present in the range. In this case, 1 particle was completely included in the 1 × 1 μm frame, and 0.5 particles were counted for only a part of the particles contained in the frame. And this operation is performed about five places on the surface of a nickel plating layer, and particle density can be calculated | required by averaging two measurement results except two of the maximum value and the minimum value.

[Particle size]
Examples of the second characteristic value include a value of particle diameter (average particle diameter).
That is, the average particle diameter of the granular Ni plating layer 2 in this embodiment is 0.01 μm to 0.05 μm. If this average particle diameter is less than 0.01 μm, the nickel plating becomes too fine and smooth, and sufficient adhesion to the organic resin layer cannot be obtained. On the other hand, if it exceeds 0.05 μm, the plating surface shape becomes too smooth, and sufficient adhesion to the organic resin layer cannot be obtained.
The average particle diameter is calculated by calculating the average occupied area per particle from the particle density per unit area of 1 × 1 μm obtained by observing the surface of the surface treatment film 2 with a scanning electron microscope (SEM). The diameter of a circle corresponding to the average occupied area can be calculated and obtained.

Returning to FIG. 2, after the Ni plating layer 2 is formed on the steel plate 1, the Sn plating layer 3 is formed on the Ni plating layer 2 (step 2).
At this time, the Sn plating amount (total Sn plating amount in the film of the surface-treated steel sheet) is 0.4 g / m ^{2 to} 2.0 g / m ² , preferably 1.0 g / m ^{2 to} 2.0 g / m ^2. The plating process is performed so that When the amount of Sn plating is less than 0.4 g / m ² , a sufficient Ni—Sn alloy layer or Ni—Sn—Fe alloy layer is not formed during heat treatment, and the effect of suppressing Ni elution in an acidic solution is insufficient. is there. On the other hand, when the Sn plating amount exceeds 2.0 g / m ² , the effect of suppressing the elution of Ni in the acidic solution is sufficient, but the surface of the surface-treated steel plate becomes smooth. When this is processed, the anchor effect is not sufficient and the adhesion is deteriorated.
FIG. 4 shows a state in which the Ni plating layer 2 and the Sn plating layer 3 are formed on the steel plate 1 through step 2. In the drawing, the upper surface of the Sn plating layer 3 is schematically horizontal, but the upper surface of the actual Sn plating layer 3 is formed with some undulations (unevenness) following the granular Ni plating layer 2.

After step 2, a reflow process (melt heat treatment) is performed on the steel plate 1 on which the Ni plating layer 2 and the Sn plating layer 4 are formed (step 3).
Through this reflow process, as shown in FIG. 5, the first alloy layer 3 (Ni—Sn alloy or Ni—Sn—Fe alloy) is formed near the interface between the Ni plating layer 2 and the Sn plating layer 3. The
Furthermore, as shown in FIG. 5, in the present embodiment, a second alloy layer 5 is formed between the steel plate 1 and the Ni plating layer 2. The second alloy layer includes a Ni—Fe alloy because Fe as a component of the steel plate 1 is alloyed with Ni of the Ni plating layer 2 by thermal diffusion.
As described above, in the present embodiment, the surface treatment layer on the steel plate 1 includes at least one of the first alloy layer 3 and the second alloy layer 5 described above.
That is, as is apparent from FIG. 5, the surface-treated steel sheet ST of the present embodiment has a Ni—Fe alloy layer, a Ni plating layer, a Ni—Sn—Fe alloy layer, or a Ni—Sn layer from the steel plate (base material) side. It can also be seen that a form in which the Sn plating layer is laminated in this order can also be taken.

And the surface treatment layer of this embodiment formed on the steel plate 1 through steps 1 to 3 has the following characteristics.
That is, the first feature is that the Sn alloying ratio is 20% or more and 90% or less with respect to the Sn plating amount. Here, the “Sn alloying rate” is an index indicating how much Sn is alloyed in the surface treatment layer with respect to the amount of Sn plated on the steel sheet 1, for example, the following formula ( It can be calculated in 1).

  The second feature is that the atomic ratio (Ni / Sn) of Ni and Sn after tin removal is 0.05 or more and 5.0 or less. A known technique can be applied to the “tin removal” method. Examples of the method include dissolving the metal tin formed on the surface by anodic electrolysis in an alkaline aqueous solution.

Since the surface-treated steel sheet ST has the above-described characteristics, the heating temperature during the reflow process of the present embodiment is characterized in that the reached temperature of the steel sheet 1 (base material) is 180 to 240 ° C.
By setting the heating temperature in this reflow process to an ultimate temperature based on the steel sheet 1, and further setting this ultimate temperature to 180 to 240 ° C., the alloying rate of Sn is 20% or more and 90% or less with respect to the plating amount. In addition, a surface-treated steel sheet ST having a Ni / Sn atomic ratio (Ni / Sn) of 0.05 or more and 5.0 or less after tin removal can be obtained. In general, the reflow treatment is performed at a temperature higher than the melting point of tin (232 ° C.), but Ni and Sn diffuse and alloy even at temperatures lower than that, and can be applied. This indicates that, in the step of thermocompression bonding the organic resin film on the surface-treated steel plate ST that has not been subjected to the reflow treatment, the method can be applied to the case where the surface-treated steel plate is heated below the melting point of tin.

Note that when the Sn alloying ratio is less than 20% of the plating amount, Ni is likely to be eluted in the acidic aqueous solution.
On the other hand, when the alloying ratio of Sn exceeds 90% with respect to the plating amount, the effect of suppressing the dissolution of Ni by metallic tin is reduced and Ni is likely to be eluted. Further, Ni that is not alloyed during reflow treatment (also referred to as unalloyed Ni) is likely to occur, and as a result, Ni is likely to be eluted.
Further, if the atomic ratio of Ni and Sn is less than 0.05, the corrosion resistance becomes insufficient when the Sn plating amount is less than 2.0 g / m ² .
On the other hand, when the atomic ratio of Ni and Sn exceeds 5.0, Ni is likely to elute. This is probably because unalloyed Ni is likely to occur during the reflow process.
The atomic ratio (Ni / Sn) between Ni and Sn after this tin removal is preferably 0.05 to 1.0, particularly preferably 0.05 to 0.5.
The surface-treated steel sheet ST of the present embodiment is manufactured through the processing of Step 1 to Step 3 described above.

<Coating layer as chromium-free treatment>
As shown in Step 4 and FIG. 5 of FIG. 2, for the steel plate 1 on which the surface treatment layer described above is formed, Zr is further provided on the surface treatment layer or on the surface of the steel plate 1 opposite to the surface treatment layer. The coating layer 6 as a film of at least one oxide of Ti, Ti, and Al (for example, ZrO ₂ , TiO ₂ , Al ₂ O _3, etc.) may be formed. That is, in the present embodiment, the coating layer 6 is not essential, but it is more preferable if the coating layer 6 is provided on the surface treatment layer.
In addition, the coating layer 6 of this embodiment may contain not only the above oxide but also a hydroxide. Therefore, the “oxide” in the present embodiment is used as a concept that may contain a hydroxide at least in part.

  The formation of the coating layer 6 is not limited to the above. For example, (1) a film having a form utilizing a passivating action such as molybdic acid (including a form added with a predetermined ratio of phosphoric acid) or tungstic acid, (2) Reactive coatings based on fluorides, phosphates, nitrates and sulfates of transition metals such as Ti, Zr, V, Mn, Ni and Co, and polypinylphenol derivatives and polyacrylic acid Coated coating type coatings, (3) reactive type coatings based on chlorides and nitrates of rare elements such as Y, La, and Ce, or oxyacid salts thereof with molybdic acid, tungstic acid, etc. Coatings in the form of coatings blended with (4) coatings based on chelating agents such as polyphenolic carboxylic acids such as tannic acid and thiourea containing sulfur and nitrogen It may be used a film of various forms.

  The coating layer 6 may contain an oxide of phosphorus in addition to the above oxide. Before forming the coating layer 6, a phosphate compound layer made of Fe or Sn may be formed, or may be formed in the form of a phosphate compound such as Zr phosphate or Al phosphate. By containing phosphoric acid, the adhesion with the organic resin layer can be improved and plating defects such as pinholes can be reduced.

The coating amount of the coating layer 6 is preferably ¹ to 30 mg / m ² for all of Zr oxide, Al oxide, and Ti oxide, and 0.1 to 5 mg / m ² for phosphorus oxide.
Among these, regarding the oxide of phosphorus, when forming a coating layer mainly composed of oxides of P (phosphorus) and Al (aluminum), the coating amount of Al is preferably 1 to 15 mg / m ² . Yes, the preferable coating amount of P for Al is 0.5 to 3 mg / m ² .

<Organic resin layer>
As shown in Step 5 of FIG. 2 and FIG. 6, the organic resin layer 7 may be formed on the surface-treated steel plate ST described above. More specifically, after the above-described surface-treated steel plate ST is manufactured, or when the above-described coating layer 6 is formed, after the formation of the coating layer 6, an organic resin layer 7 is formed thereon to form an organic layer. A resin-coated steel sheet RT is manufactured.
Various known paints can be applied to the organic resin layer 7. For example, as the thermoplastic resin, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, olefin resin film such as ionomer, polyethylene terephthalate, polybutylene terephthalate, etc. An unstretched film or a biaxially stretched film such as a polyester film, a polyvinyl chloride film, or a polyvinylidene chloride film, or a polyamide film such as nylon 6, nylon 6, 6, nylon 11, or nylon 12 can be used. Among these, non-oriented polyethylene terephthalate obtained by copolymerizing isophthalic acid is particularly preferable. Moreover, the organic material for comprising such an organic resin layer 7 may be used independently, and different organic materials may be blended and used. Moreover, the multilayer structure which consists of a some organic resin layer may be sufficient. As the thermosetting resin, an epoxy-phenol resin, a polyester resin, or the like can be used.

Of these, polyester resins are preferred because they are easy to paint and bake, have excellent workability, adhesion to metals, and retort resistance, and do not generate toxic or corrosive gases during incineration. Examples of such a polyester resin include any one of ethylene terephthalate, butylene terephthalate, 1,4-cyclohexanedimethyl terephthalate, ethylene isophthalate, butylene isophthalate, ethylene adipate, butylene adipate, ethylene naphthalate, and butylene naphthalate. Examples include polyester resins containing the above esters.
Furthermore, the organic resin layer 7 of the present embodiment may be a multilayer film composed of a plurality of layers, and may preferably be composed of two or three layers.

<Container>
As shown in Step 6 and FIG. 7 of FIG. 2, the above-described surface-treated steel plate ST and organic resin-coated steel plate RT of the present embodiment can be applied to various containers C. FIG. 7 shows a seamless can using the surface-treated steel sheet ST and the organic resin-coated steel sheet RT of the present embodiment. FIG. 7 shows an example in which the surface treatment layer, the coating layer 6 and the organic resin layer 7 described above are coated on the inner surface side of the seamless can. May be formed. Alternatively, the surface treatment layer, the coating layer 6, and the organic resin layer 7 described above may be coated on the outer surface side of the seamless can.

<Example>
Hereinafter, the present invention will be described more specifically with reference to examples.
<Example 1>
A cold rolled steel sheet of low carbon aluminum killed steel having a thickness of 0.225 mm was used as a base material. First, this steel sheet is electrolytically degreased in an alkaline aqueous solution, washed with water, further washed with sulfuric acid and washed with water, and then the Ni plating film amount is set to 0.4 g / m ² in a nickel plating bath. Formed. Then, the Sn plating layer was formed by setting the coating amount of Sn plating to 1.5 g / m ^{2 in} a tin plating bath.
In this example, the particle density in the Ni plating layer was 800 particles / μm ² and the average particle size was 0.03 μm.
The surface-treated steel sheet ST obtained under the above conditions is subjected to reflow treatment (melting heat treatment), and the above alloy layer (Ni—Sn alloy layer, Ni—Fe alloy layer or Ni—Sn—Fe alloy layer). Formed. In addition, as reflow conditions at this time, the melt heat treatment was performed for 4.2 seconds at a temperature of 210 ° C. below the melting point of Sn.
As described above, the heating temperature of the reflow conditions can be selected as appropriate when the steel sheet reaches 180 to 240 ° C. In addition, regarding the reflow conditions, the heating time can be appropriately selected from 0.1 second to 8 seconds. In general, the reflow treatment is performed at a temperature higher than the melting point of tin (232 ° C.), but Ni and Sn diffuse and alloy even at temperatures lower than that, and can be applied.

The specific plating bath conditions were as follows.
<Nickel plating bath and plating conditions for granular Ni plating layer>
Nickel sulfate 40g / L
Ammonium sulfate 20g / L
Citric acid 15g / L
pH 4.0
Bath temperature 45 ° C
Current density 50A / dm ²
In addition, you may adjust the quantity of nickel sulfate suitably if it is 40-60 g / L. Further, the amount of ammonium sulfate may be appropriately adjusted as long as it is 20 to 100 g / L.
Further, those using this nickel plating bath are described as “particulate” in Table 1.

<Tin plating bath and plating conditions>
Stannous sulfate 80g / L
Phenolsulfonic acid 60g / L
Additive A (ethoxylated α-naphthol) 3 g / L
Additive B (Ethoxynaphtholsulfonic acid) 3g / L
pH 1 or less Bath temperature 40 ° C
Current density 10A / dm ²
In addition, you may adjust suitably the quantity of stannous sulfate if it is 10-200 g / L. Further, the amount of phenolsulfonic acid sulfuric acid may be appropriately adjusted as long as it is 5 to 100 g / L.

<Example 2>
The same procedure as in Example 1 was conducted except that the coating amount of Ni plating (before tin removal) was 0.5 g / m ² and the coating amount of Sn plating (before tin removal) was 0.8 g / m ² .

<Example 3>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 0.9 g / m ² and the coating amount of Sn plating (before tin removal) was 1.4 g / m ² .

<Example 4>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 0.9 g / m ² and the coating amount of Sn plating (before tin removal) was 0.7 g / m ² .

<Example 5>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.02 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same procedure as in Example 1 was conducted except that the amount was 0.0 g / m ² .

<Example 6>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.02 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same operation as in Example 1 was conducted except that the amount was set to 8 g / m ² .

<Example 7>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.05 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same procedure as in Example 1 was conducted except that the amount was 0.0 g / m ² .

<Example 8>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.05 g / m ² , and the Sn plating film amount (before tin removal) is 1. It was carried out in the same manner as in Example 1 except that it was set to 0.9 g / m ² .

<Example 9>
The heating temperature during the reflow process is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.1 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same procedure as in Example 1 was conducted except that the amount was 0.0 g / m ² .

<Example 10>
The heating temperature during the reflow process is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.1 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same operation as in Example 1 was conducted except that the amount was set to 8 g / m ² .

<Example 11>
The heating temperature during reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.4 g / m ² , and the Sn plating film amount (before tin removal) is 1. It carried out like Example 1 except having set it as .3g / m < ² >.

<Example 12>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.9 g / m ² , and the Sn plating film amount (before tin removal) is 1. The same operation as in Example 1 was conducted except that the amount was 0.6 g / m ² .

<Example 13>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 1.0 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 0.7 g / m ² .

<Example 14>
As a Ni plating bath, a Watt bath shown under the following conditions was used.
In forming the Ni plating layer, the coating amount of the Ni plating was set to 0.07 g / m ² so that the shape of the coating was not granular. Further, in the formation of the Sn plating layer, the coating amount of Sn plating was set to 0.83 g / m ² . Furthermore, the temperature in the reflow treatment was 240 ° C., and the heating time was 5.6 seconds.

In addition, the specific conditions of the Watt bath in this Example 14 and Examples 15-17 mentioned later are as follows.
<Nickel plating bath and plating conditions in Watt bath>
Nickel sulfate 240g / L
Nickel chloride 45g / L
Boric acid 30g / L
Additives (saccharin, etc.) 2g / L
pH 4.0
Bath temperature 45 ° C
Current density 5A / dm ²
In addition, those using a Watt bath are described as “uniform” in Table 1.

<Example 15>
The same operation as in Example 14 was performed except that the coating amount of Sn plating was 1.5 g / m ² .

<Example 16>
The same operation as in Example 14 was performed except that the coating amount of Ni plating was 0.14 g / m ² .

<Example 17>
The same operation as in Example 14 was performed except that the coating amount of Ni plating was 0.14 g / m ² and the coating amount of Sn plating was 1.5 g / m ² .

<Example 18>
As a post-treatment, the surface-treated steel sheet ST of Example 5 was subjected to anodic electrolysis in a treatment solution having a pH of 2.4 containing phosphoric acid and sodium dihydrogen phosphate as main components, followed by washing with water. Furthermore, by performing cathodic electrolysis in a pH 3.0 treatment bath containing aluminum nitrate as a main component, followed by washing with water and drying, P (phosphorus) and Al (aluminum) on the surface-treated steel sheet ST. A coating layer mainly composed of oxide was formed.

<Example 19>
For the surface-treated steel sheet ST of Example 5, as a post-treatment, by performing a cathodic electrolysis treatment in a treatment bath having a pH of 3.0 containing aluminum nitrate and phosphoric acid as main components, followed by washing with water and drying, A coating layer mainly composed of oxides of P (phosphorus) and Al (aluminum) was formed on the surface-treated steel plate ST.

<Comparative Example 1>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 0.5 g / m ² and the coating amount of Sn plating (before tin removal) was 0.4 g / m ² .

<Comparative Example 2>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 1.0 g / m ² and the coating amount of Sn plating (before tin removal) was 0.4 g / m ² .

<Comparative Example 3>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 1.8 g / m ² and the coating amount of Sn plating (before tin removal) was 0.4 g / m ² .

<Comparative Example 4>
The same procedure as in Example 1 was performed except that the coating amount of Ni plating (before tin removal) was 1.8 g / m ² and the coating amount of Sn plating (before tin removal) was 0.7 g / m ² .

<Comparative Example 5>
The heating temperature during the reflow process is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.5 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 4 g / m ² .

<Comparative Example 6>
The heating temperature during the reflow process is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.5 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 0.7 g / m ² .

<Comparative Example 7>
The heating temperature during reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 0.9 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 0.7 g / m ² .

<Comparative Example 8>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 1.0 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 4 g / m ² .

<Comparative Example 9>
The heating temperature during the reflow process is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 1.7 g / m ² , and the Sn plating film amount (before tin removal) is 1. It carried out like Example 1 except having set it as .3g / m < ² >.

<Comparative Example 10>
The heating temperature during the reflow treatment is 240 ° C., the heating time is 5.6 seconds, the Ni plating film amount (before tin removal) is 1.8 g / m ² , and the Sn plating film amount (before tin removal) is 0. The same operation as in Example 1 was conducted except that the amount was 4 g / m ² .

<Comparative Example 11>
The heating temperature during the reflow treatment is 160 ° C., the heating time is 3.0 seconds, the Ni plating film amount (before tin removal) is 0.4 g / m ² , and the Sn plating film amount (before tin removal) is 1. It carried out like Example 1 except having set it as .3g / m < ² >.

<Comparative Example 12>
The heating temperature during the reflow treatment is 260 ° C., the heating time is 6.2 seconds, the Ni plating film amount (before tin removal) is 0.4 g / m ² , and the Sn plating film amount (before tin removal) is 1. It carried out like Example 1 except having set it as .3g / m < ² >.

<Reference Example 1>
Ni plating was performed under the same plating bath and plating conditions as those of the above-described examples. The coating amount of Ni plating was 0.5 g / m ² .

<Reference Example 2>
The same procedure as in Reference Example 1 was performed except that the coating amount of Ni plating was 1.0 g / m ² .

<Reference Example 3>
It carried out similarly to the reference example 1 except the film quantity of Ni plating having been 2.0 g / m < ² >.

In each of the above Examples and Comparative Examples, the film amount and Ni elution amount were measured by the following methods.
<Measurement of coating amount of Ni and Sn>
The coating amount of each of Ni and Sn on the obtained surface-treated steel sheet ST was measured with a fluorescent X-ray apparatus (ZSX100e, manufactured by Rigaku Corporation). In addition, the surface treated steel plate ST was subjected to anodic electrolysis in an alkaline aqueous solution to dissolve the metal Sn formed on the surface, thereby measuring the coating amounts of Ni and Sn when only the alloy layer was used.

<Measurement of Ni elution amount>
The obtained surface-treated steel sheet ST was cut out into a disk having a diameter of 49 mm, sealed at the end face, and then placed in a glass container and immersed in a 1.5% aqueous acetic acid solution. The container was retorted at 125 ° C. for 30 minutes, and the Ni concentration in the acetic acid aqueous solution after retorting was measured by a known ICP analysis method. Further, with respect to some samples (Example 13 and Reference Example), the same evaluation was performed with a model solution (mixed aqueous solution of 0.5% citric acid and 0.5% NaCl).
[Evaluation index for Ni elution amount]
A: Ni concentration is less than 0.005 ppm B: Ni concentration is less than 0.01 ppm.
X: Ni concentration is 0.01 ppm or more. In the evaluation, it was judged that there was practical aptitude when the Ni concentration (Ni elution amount) was less than 0.01 ppm.

  Table 1 shows the evaluation results of various specification values and Ni elution amounts regarding the examples and comparative examples described above.

An organic resin-coated steel sheet RT was produced for a part of the above-described Examples and Reference Examples, and corrosion resistance and adhesion were evaluated for the produced organic resin-coated steel sheet RT.
The surface-treated steel sheets ST produced in Examples 3, 9 to 11 and 12 were subjected to cathodic electrolysis as a post-treatment in a pH 3.0 treatment bath mainly composed of ammonium zirconium fluoride. By washing with water and drying, a coating layer composed mainly of an oxide of Zr (zirconium) was formed on the surface-treated steel sheet ST.
Further, as a post-treatment, the surface-treated steel plate ST produced in Examples 5 and 6 is subjected to cathodic electrolysis in a pH 3.0 treatment bath mainly composed of aluminum nitrate, and then washed with water and dried. As a result, a coating layer mainly composed of an oxide of Al (aluminum) was formed on the surface-treated steel sheet ST.

As Reference Example 4, only Sn plating was performed on the same substrate as in Example 1, and the coating amount of Sn plating was 2.8 g / m ² . The surface-treated steel sheet ST thus produced is subjected to cathode electrolysis in a treatment liquid containing chromium as a main component as post-treatment, and then washed with water and dried, so that Cr (chromium) is formed on the surface-treated steel sheet ST. A coating layer mainly composed of the oxide was formed.
A surface-treated steel sheet on which a coating layer of an oxide of Zr, Al, Al and P, or Cr is formed is heat-treated at a temperature of 190 ° C. for 10 minutes, and the coating thickness after baking and drying is 70 mg / dm ^2. After coating the epoxy phenol-based paint so as to become, an organic resin-coated steel sheet obtained by coating an organic resin layer on the surface-treated steel sheet by baking at a temperature of 200 ° C. for 10 minutes was obtained. The obtained organic resin-coated steel sheet was subjected to evaluation of paint adhesion or corrosion resistance.

<Evaluation of paint adhesion>
The obtained organic resin-coated steel sheet was subjected to a retort treatment at a temperature of 125 ° C. for 30 minutes, and cuts having depths reaching the steel sheet at intervals of 5 mm were put in a grid pattern. Thereafter, the tape was applied to the grid-like cuts and then peeled off. As a paint adhesion evaluation method, the degree of peeling was visually observed and evaluated according to the following criteria. In addition, paint adhesion evaluation was performed about all the Examples and the comparative examples.
[Evaluation index for paint adhesion]
3 points: As a result of visual judgment, peeling of the paint was not recognized.
2 points: As a result of visual judgment, peeling of the paint was recognized at an area ratio of 1/5 or less.
1 point: As a result of visual determination, peeling of the paint was recognized at an area ratio exceeding 1/5.
In addition, in the evaluation of paint adhesion, when the evaluation is 3 points or more according to the above criteria, the surface-treated steel sheet (or organic resin-coated steel sheet) has sufficient paint adhesion when used as a food can application. Judged that it was.

<Evaluation of corrosion resistance to model liquid>
About the obtained organic resin coated steel plate, the corrosion resistance in the model liquid mentioned above was evaluated. As the model solution, an aqueous solution in which NaCl and citric acid were dissolved at 1.5% by weight was used.
More specifically, the obtained organic resin-coated steel sheet was cut into 40 mm square, and then the cut surface was protected with a 3 mm width tape to prepare a test piece. Next, an Erichsen tester (manufactured by Coating Tester Co., Ltd.) is used to make a cross-cut flaw that reaches the steel plate using a cutter on the prepared test piece so that the intersection of the cross-cut becomes the apex of the overhanging portion. 3 mm overhanging was performed. The test piece subjected to the overhang processing was put in a sealed container and filled with the above-described model solution, and then stored in an environment of 90 ° C. for 24 hours.
Then, this steel plate was taken out from the sealed container, the degree of corrosion was visually observed, and the following criteria were evaluated. In addition, corrosion resistance evaluation (model liquid) was performed about said Example and all the comparative examples.
[Evaluation index for corrosion resistance]
3 points: As a result of visual judgment, the degree of corrosion was clearly smaller than that of Reference Example 4.
2 points: As a result of visual judgment, the degree of corrosion was equivalent to that of Reference Example 4.
1 point: As a result of visual judgment, the degree of corrosion was clearly greater than that of Reference Example 4.
In addition, in the corrosion resistance evaluation (model solution), when the evaluation is 2 points or more according to the above criteria, the surface-treated steel plate (or organic resin-coated steel plate) has sufficient corrosion resistance when used as a food can application. It was judged that.

  Table 2 shows the evaluation results of paint adhesion and corrosion resistance regarding each of the examples and comparative examples described above.

  Each example was confirmed to have excellent corrosion resistance and paint adhesion at the same time while suppressing the amount of Ni elution. On the other hand, it was confirmed that none of the comparative examples had these characteristics at the same time.

  It should be noted that the above-described embodiment and each example can be variously modified without departing from the spirit of the present invention.

  As described above, the surface-treated steel sheet, the organic resin-coated steel sheet and the container using the same according to the present invention simultaneously have corrosion resistance and paint adhesion while suppressing elution of Ni, and can be applied to a wide range of industries. Is possible.

1 Steel plate (base material)
2 Ni plating layer 3 First alloy layer 4 Sn plating layer 5 Second alloy layer 6 Coating layer 7 Organic resin layer ST Surface-treated steel sheet RT Organic resin-coated steel sheet C Container

Claims (8)

A surface-treated steel sheet on which Ni plating and Sn plating are formed,
Steel sheet,
Ni plating layer formed on the steel plate, alloy layer formed on the Ni plating layer, and Sn plating layer formed on the alloy layer ,
The alloy layer includes at least one of a Ni—Sn alloy layer and a Ni—Sn—Fe alloy layer ,
Sn alloying rate is 20% or more and 90% or less with respect to the plating amount of the Sn plating layer,
The total Ni plating amount in the film of the surface-treated steel sheet is 0.01 g / m ² to 2.0 g / m ² , and the total Sn plating amount is 0.4 g / m ² to 2.0 g / m ² . ,
A surface-treated steel sheet having an atomic ratio Ni / Sn between Ni and Sn after detinning of 0.05 to 5.0. A Ni-Fe alloy layer;
The said Ni-Fe alloy layer, the said Ni plating layer, the said Ni-Sn-Fe alloy layer or the said Ni-Sn layer, and the said Sn plating layer are laminated | stacked in this order from the said steel plate side. Surface treated steel sheet. The surface-treated steel sheet according to claim 1 or 2 , wherein a coating layer containing at least one oxide of Zr, Ti, and Al is formed on at least one surface of the surface-treated steel sheet. The surface-treated steel sheet according to claim 3 , wherein the coating layer contains an oxide of P. An organic resin-coated steel sheet obtained by further coating an organic resin layer on the surface-treated steel sheet according to any one of claims 1 to 4 . A container comprising the organic resin-coated steel sheet according to claim 5 . A method for producing a surface-treated steel sheet in which a Ni plating layer and a Sn plating layer are formed,
Forming a Ni plating layer on the steel sheet;
Forming Sn plating layer on the Ni plating layer by performing Sn plating on the steel sheet on which the Ni plating layer is formed;
After the Sn plating layer is formed, the steel sheet is heat-treated so that the ultimate temperature of the steel sheet is 180 to 240 ° C., whereby a Ni—Sn alloy layer , a Ni—Fe alloy layer , And forming at least one of a Ni—Sn—Fe alloy layer ,
The Sn alloying rate in the surface-treated steel sheet is 20% or more and 90% or less with respect to the plating amount of the Sn plating layer, and the total Ni plating amount in the film of the surface-treated steel sheet is 0.01 g / m ² to 2. 0 g / m ² , the total Sn plating amount is 0.4 g / m ² to 2.0 g / m ² , and the atomic ratio Ni / Sn between Ni and Sn after detinning is 0.05 or more and 5.0 The manufacturing method of the surface treatment steel plate characterized by the following. The step of forming the Ni plating layer, claim particle density 500 / [mu] m ² to 1000 pieces / [mu] m ² a is granular Ni particles having an average particle diameter is 0.01μm~0.05μm is formed 7 A method for producing a surface-treated steel sheet according to claim 1.