TW201529892A - Steel sheet for containers - Google Patents

Abstract

Provided is a steel sheet for containers, which has excellent adhesion to resins and corrosion resistance. This steel sheet for containers comprises: a tin-plated steel sheet wherein at least a part of the surface of a steel sheet is covered by a tin plating layer; and a coating film that is arranged on the tin plating layer-side surface of the tin-plated steel sheet. The coating film contains P, Zr, Ti and silica. With respect to the coating film, the amount of adhered P in terms of elemental metal per one surface of the tin-plated steel sheet is 1-10 mg/m2; the amount of adhered Zr in terms of elemental metal per one surface of the tin-plated steel sheet is 1-40 mg/m2; the amount of adhered Ti in terms of elemental metal per one surface of the tin-plated steel sheet is more than 0.5 mg/m2 but less than 10 mg/m2; and the amount of adhered Si in terms of elemental metal per one surface of the tin-plated steel sheet is 1-40 mg/m2.

Description

Steel plate for containers

The present invention relates to a steel sheet for containers.

As a steel sheet for containers (a surface-treated steel sheet for cans), a tin-plated steel sheet called "tinplate" has been widely used. Such a tin-plated steel sheet is usually formed by immersing the steel sheet in an aqueous solution containing a hexavalent chromium compound such as dichromic acid or by chromate treatment such as electrolytic treatment in the solution to form a tin-plated surface. Chromate film.

However, based on recent environmental problems, the action of restricting the use of Cr has been circulated in various fields, and there have been several proposals for the treatment of steel sheets for containers instead of chromate treatment.

For example, Patent Document 1 discloses that "the resin is excellent in adhesion without using Cr" ([0013]), and "a surface-treated metal sheet having at least one surface of the metal sheet. A film containing Zr and O, the amount of F of the film is less than 0.1 mg/m ² on each side ("Patent scope item 1]), and the "metal plate" referred to herein is "plated Sn plate" ( Apply for patent scope item 3)).

[Advanced technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2008-184630

In recent years, consumers have increasingly demanded aesthetics, so the various characteristics required for steel sheets for containers are becoming increasingly strict.

The inventors of the present invention have further studied the steel sheet for containers (surface-treated metal sheets) disclosed in Patent Document 1. As a result, it has been found that when the resin such as a PET film is laminated and then subjected to high-temperature sterilization treatment, the film adhesion (hereinafter referred to as "resin adhesion") of the resin is insufficient.

Further, the present inventors have found that when a coating film of an epoxy phenol-based paint is formed on a steel sheet for a container and then immersed in tomato juice under specific conditions, corrosion resistance such as peeling of the coating film or occurrence of corrosion may occur. Poor situation.

The present invention has been developed in view of the above points, and an object thereof is to provide a steel sheet for a container which is excellent in resin adhesion and corrosion resistance.

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, it has been found that by containing a specific amount of a specific component in the coating film for a steel sheet for a container, the resin adhesion and the corrosion resistance are both good and the finish is completed. this invention.

That is, the present invention provides the following (1) to (5).

(1) A steel sheet for a container, comprising: a tin-plated steel sheet coated with a tin-plated layer on at least a part of a surface of the steel sheet; and a film disposed on a surface of the tin-plated steel sheet on a side of the tin-plated layer; the film contains P, Zr And Ti and cerium oxide, the coating amount of the film on the surface of the tin-plated steel sheet in the range of 1 to 10 mg/m ² , and the amount of Zr conversion on each side of the tin-plated steel sheet is 1 to 40 mg / m ² , the adhesion amount in terms of Ti per one surface of the tin-plated steel sheet is more than 0.5 mg/m ² and less than 10 mg/m ² , and the adhesion amount per Si of the tin-plated steel sheet is 1 to 40 mg/m. ² .

(2) The steel sheet for a container according to the above (1), wherein the coating film has a Ti loading amount of more than 3 mg/m ² and less than 10 mg/m ² on each surface of the tin-plated steel sheet.

(3) The steel sheet for a container according to the above (1) or (2), wherein an atomic ratio (Ti/Zr) of Ti to Zr on the outermost surface of the film opposite to the side of the tin-plated steel sheet is 0.05 to 2.0, Si and The atomic ratio (Si/Zr) of Zr is 0.1 to 3.0.

(4) The steel sheet for a container according to any one of the above aspects, wherein the atomic ratio of P to Zr (P/Zr) of the surface of the film opposite to the side of the tin-plated steel sheet is 0.10 or more. And less than 0.50.

(5) The steel sheet for a container according to any one of the above-mentioned (1), wherein the tin-plated steel sheet is formed using a steel sheet having a nickel-containing layer on its surface.

According to the invention, it is possible to provide a steel sheet for a container which is excellent in resin adhesion and corrosion resistance.

1‧‧‧Steel plates for containers

2‧‧‧film

3‧‧‧ cut parts of steel plate

4‧‧‧ weights

5‧‧‧ peeling long

Figure 1 is a schematic view showing a 180 degree peel test.

[Steel plate for containers]

The steel sheet for a container of the present invention has a tin-plated steel sheet and a film disposed on the surface of the tin-plated steel sheet on the side of the tin-plated layer. Moreover, since this film contains P, Zr, and Ti in a specific amount, and contains cerium oxide in a specific amount, it is excellent in resin adhesiveness and corrosion resistance.

The details of tin-plated steel sheets and coatings are detailed below. First of all, the details of the tinplate are detailed.

<tinned steel plate>

The tin-plated steel sheet has a tin-plated layer of at least a part of the surface of the steel sheet and the coated steel sheet. The details of the steel plate and the tin plating layer are detailed below.

(steel plate)

The type of the steel plate in the tin-plated steel sheet is not particularly limited. Steel plates are generally available for use as container materials (eg, low carbon steel, very low carbon steel) board). The manufacturing method and material of the steel sheet are also not particularly limited. It can be produced by a general steel sheet manufacturing step by hot rolling, pickling, cold rolling, annealing, quenching and tempering, and the like.

The steel sheet may be formed by using a nickel-containing layer (Ni-containing layer) on the surface thereof, and a tin-plated layer may be formed on the Ni-containing layer. A tin-plated layer containing island-shaped Sn can be formed by applying tin to a steel sheet having a Ni-containing layer. As a result, the weldability is improved.

Nickel may be contained as the Ni containing layer. For example, a Ni plating layer (Ni layer), a Ni-Fe alloy layer, or the like can be given.

There is no particular limitation on the method of imparting a Ni-containing layer to the steel sheet. For example, a known method such as electroplating can be mentioned. Further, when the Ni-containing alloy layer is provided as a Ni-containing alloy layer, the Ni-Fe alloy layer can be formed by alloying Ni on the surface of the steel sheet by electroplating and then coordinating the Ni diffusion layer by annealing.

The amount of Ni in the Ni-containing layer is not particularly limited, and the amount of Ni per side is preferably from 50 to 2,000 mg/m ² . If it is within the above range, it is also advantageous in terms of cost.

(tin plating)

The tin-plated steel sheet has a tin-plated layer on the surface of the steel sheet. The tin plating layer may be provided on at least one surface of the steel sheet, or may be provided on both sides.

The Sn adhesion amount on each side of the steel plate in the tin plating layer is preferably 0.1 to 15.0 g/m ² . When the Sn adhesion amount is within the above range, the steel sheet for a container is more excellent in corrosion resistance. In particular, 0.2 to 15.0 g/m ^{2 is} more preferable. Based on the viewpoint of excellent workability, 1.0 to 15.0 g/m ^{2 is} more preferable.

In addition, the Sn adhesion amount can be measured by surface analysis by a coulometric method or a fluorescent X-ray. In the case of the fluorescent X-ray, a known amount of Sn adhesion amount is used, and a calibration curve relating to the amount of Sn is specified in advance, and the amount of Sn is relatively specified using the calibration line.

The tin-plated layer is a layer in which at least a part of the surface of the steel sheet is coated, and may be a continuous layer or a discontinuous island shape.

The tin plating layer includes, in addition to the tin plating layer, which is a plating layer of a tin monomer obtained by plating tin, and the lowermost layer of the plating layer of the tin monomer obtained by heating and melting the tin after the tin plating. A tin plating layer of an Fe-Sn alloy layer is partially formed by a plating/steel plate interface of a tin monomer.

In addition, the tin-plated layer also includes tin plating on a steel sheet having a Ni-containing layer on the surface, and heating and melting the tin by electric heating or the like in the lowermost layer of the plating layer of the tin monomer (tin plating/steel plate interface) A tin-plated layer of an Fe-Sn-Ni alloy layer, an Fe-Sn alloy layer or the like is partially formed.

As a method of producing the tin-plated layer, a well-known method (for example, a plating method or a plating method immersed in molten Sn) may be mentioned.

For example, a phenolsulfonic acid tin plating bath, a methanesulfonic acid tin plating bath, or a halogen-based tin plating bath may be used to plate the surface of the steel sheet in such a manner that the adhesion amount per surface becomes a specific amount (for example, 2.8 g/m ² ). After Sn, heat-melting treatment is performed at a temperature equal to or higher than the melting point of Sn (231.9 ° C) to produce a tin-plated layer in which an Fe-Sn alloy layer is formed in the lowermost layer of the plating layer of the tin monomer. When the heat-melting treatment is omitted, a plating layer of a tin monomer can be produced.

Further, when the steel sheet has a Ni-containing layer on the surface thereof, a plating layer of a tin monomer can be formed on the Ni-containing layer, and heat-melting treatment is performed. At the lowermost layer (tin plating/steel plate interface) of the tin monomer plating layer, an Fe-Sn-Ni alloy layer, an Fe-Sn alloy layer, or the like is formed.

<film>

The film system is disposed on the surface of the tin plating layer side of the tin-plated steel sheet.

The film contains, as a component thereof, Si of P, Zr, Ti, and cerium oxide. First, the components will be described in detail below, and then the method for forming the film will be described in detail.

(P, Zr, Ti, and Si)

The film contains P (phosphorus), and the amount of adhesion (in the following or "P adhesion amount") of each side of the tin-plated steel sheet is 1 to 10 mg/m ² . When the P adhesion amount is within the above range, the steel sheet for a container is excellent in corrosion resistance.

If the P adhesion amount is less than 1 mg/m ² , the corrosion resistance is not good. In addition, when it is more than 10.0 mg/m ² , the P deposition amount is extremely difficult from the viewpoint of the stability of the treatment liquid, and even if it is ensured, aggregation failure occurs in the film to lower the resin adhesion.

The film contains Zr (zirconium element), and the amount of Zr conversion (hereinafter referred to as "Zr adhesion amount") on each side of the tin-plated steel sheet is 1 to 40 g/m ² . When the Zr adhesion amount is within the above range, the steel sheet for a container is excellent in resin adhesion and corrosion resistance. In particular, from the viewpoint of excellent cost performance, 1 to 25 mg/m ^{2 is} particularly preferable.

When the Zr adhesion amount is less than 1 mg/m ² , the resin adhesion and the corrosion resistance are not good. Further, when the Zr adhesion amount is more than 40.0 mg/m ^{2 ,} there is no problem in performance. However, in order to secure the amount of adhesion, the cost of the treatment liquid increases and the cost of high current density increases.

The film contains Ti (titanium element), and the adhesion amount (hereinafter referred to as "Ti adhesion amount") in terms of Ti on each side of the tin-plated steel sheet is more than 0.5 mg/m ² and less than 10 mg/m ² . When the Ti adhesion amount is within the above range, the steel sheet for a container is excellent in resin adhesion. Further, insofar as the resin adhesion is more excellent, the Ti adhesion amount is preferably more than 3 mg/m ² and less than 10 mg/m ² .

When the Ti adhesion amount is 0.5 mg/m ² or less, the resin adhesion is poor. Further, even if the Ti adhesion amount is 10 mg/m ² or more, there is no problem in performance. However, in order to secure the adhesion amount, the cost of the treatment liquid increases and the cost due to high current density increases.

Further, the film contains cerium oxide. When the film contains cerium oxide, the film has an appropriate uneven shape, and the inventors believe that the steel sheet for a container is excellent in resin adhesion.

Further, in the cerium oxide represented by the composition formula SiO _{2 ,} those having an amorphous shape and a spherical shape are present, and the cerium oxide contained in the film is preferably spherical cerium oxide. As a Si component in the treatment liquid to be described later, the inventors thought that the spherical cerium oxide can be contained in the coating film while maintaining its shape by using colloidal cerium oxide in which spherical cerium oxide is dispersed. At this time, the cerium oxide contained in the film is spherical, for example, by exposing the cross section of the film to a focused ion beam (FIB), and observing it by a transmission electron microscope (TEM). confirm.

In addition, the adhesion amount (hereinafter referred to as "Si adhesion amount") of the cerium oxide on the surface of the tin-plated steel sheet is 1 to 40 mg/m ² . When the Si adhesion amount is within the above range, the resin adhesion is excellent. Further, for reasons of excellent cost performance, the Si adhesion amount is preferably 1 to 25 mg/m ² .

When the Si adhesion amount is less than 1 mg/m ² , the resin adhesion is poor. Further, when the Si adhesion amount is more than 40 mg/m ² , aggregation failure occurs in the film to lower the resin adhesion.

The P adhesion amount, the Zr adhesion amount, the Ti adhesion amount, and the Si adhesion amount described above can be measured by surface analysis using fluorescent X-rays.

Further, P in the film may be contained in the form of a phosphoric acid compound such as iron phosphate, nickel phosphate, tin phosphate, zirconium phosphate or a composite compound thereof, which is formed by a reaction between a substrate (a steel sheet or a tin-plated layer). The above P adhesion amount means the P conversion amount of these phosphate compounds.

The Zr in the film may be contained in the form of a zirconium compound such as zirconium oxide, zirconium hydroxide, zirconium fluoride, zirconium phosphate or a composite compound thereof. The above Zr adhesion amount means the Zr equivalent amount of these zirconium compounds.

Ti in the film may be contained, for example, in the form of a titanium compound such as a titanium phosphate, a titanium hydrated oxide, or a composite compound thereof. The Ti adhesion amount refers to the amount of Ti in terms of these titanium compounds.

(the preferred aspect of the film)

As a preferred aspect of the film, the atomic ratio of Ti to Zr (Ti/Zr) in the outermost surface of the film (the outermost surface opposite to the side of the tin-plated steel sheet) is 0.05 to 2.0, and Si and Zr are used. The atomic ratio (Si/Zr) is 0.1~3.0 The situation.

Further, the atomic ratio (P/Zr) of P to Zr in the outermost surface of the film (the outermost surface on the side opposite to the side of the tin-plated steel sheet) is preferably 0.10 or more and less than 0.50. If this is the case, the resin adhesion of the steel sheet for containers will be more excellent.

Further, the above atomic ratio is obtained by analyzing the peaks of Zr3d, Ti2p, P2p and Si2p by XPS (X-ray photoelectron spectroscopy) analysis.

As the XPS analysis, for example, the following conditions can be mentioned.

Device: AXIS-HS manufactured by Shimadzu / KRATOS

X-ray source: Monochromatic AlKα line (hv=1486.6eV)

Measurement area: Mixed mode 250 × 500 (μm)

[Method for Producing Steel Sheet for Container, Treatment Liquid]

The method for producing the steel sheet for a container according to the present invention is not particularly limited, and a method of forming at least a film forming step to be described later is preferred: immersion plating in a treatment liquid (hereinafter referred to as "treatment liquid of the present invention") The tin steel sheet or the tin-plated steel sheet immersed in the treatment liquid of the present invention is subjected to cathodic electrolysis to form the film (hereinafter, referred to as "the production method of the present invention").

Hereinafter, the production method of the present invention will be described. In the above description, the treatment liquid of the present invention will be described together.

<film formation step>

The film forming step is a step of forming the film on the surface of the tin-plated layer side of the tin-plated steel sheet, which is immersed in a tin-plated steel sheet (immersion treatment) in the treatment liquid of the present invention to be described later, or is applied to the impregnated steel sheet. The step of cathodic electrolysis treatment. Cathodic electrolysis treatment is more efficient than immersion treatment, and a uniform film can be obtained, which is satisfactory for this reason. Further, alternate electrolysis may be performed alternately between the cathodic electrolysis treatment and the anodic electrolysis treatment.

Hereinafter, the treatment liquid of the present invention used, the conditions of the cathodic electrolysis treatment, and the like will be described in detail.

(treatment liquid of the present invention)

The treatment liquid of the present invention contains a P component (P compound) as a P supply source for supplying the above-mentioned coating film P (phosphorus element).

The P compound contained in the treatment liquid of the present invention may, for example, be phosphoric acid such as phosphoric acid (orthophosphoric acid), sodium phosphate, sodium hydrogen phosphate, aluminum dihydrogen phosphate, magnesium dihydrogen phosphate or calcium dihydrogen phosphate and/or salt.

The content of the P compound in the treatment liquid of the present invention is preferably from 0.01 to 5.0 g/L in terms of obtaining the desired amount of phosphorus.

The treatment liquid of the present invention contains a Zr component (Zr compound) as a Zr supply source for supplying Zr (zirconium element) to the film.

The Zr compound contained in the treatment liquid of the present invention may, for example, be zirconium hexafluoride acid and/or a salt thereof (such as potassium or ammonium), zirconium oxyacetate or zirconium oxynitrate. In addition, zi Zirconium oxyacetate [ZrO(CH ₃ COO) ₂ ] may also be referred to as zirconyl acetate. Zirconium oxynitride [ZrO(NO ₃ ) ₂ ] may also be referred to as zirconyl nitrate.

The content of the Zr compound in the treatment liquid of the present invention is preferably from 0.3 to 10.0 g/L, more preferably from 0.5 to 4.0 g/L.

The treatment liquid of the present invention contains a Ti component (Ti compound) as a Ti supply source for supplying Ti (titanium element) to the film.

The Ti compound contained in the treatment liquid of the present invention may, for example, be titanium hexafluoride and/or a salt thereof (such as potassium or aluminum), titanium lactate, titanium oxyacetate or titanium oxynitrate. In addition, titanium hexafluoride may also be referred to as titanium hydrofluoric acid.

The content of the Ti compound in the treatment liquid of the present invention is preferably 0.1 to 10 g/L, more preferably 0.2 to 1.0 g/L.

The treatment liquid of the present invention further contains cerium oxide as a Si supply source for supplying Si (germanium element) to the film, and as the cerium oxide, it is preferable to contain colloidal bismuth based on the inclusion of cerium oxide in the film. Yttrium oxide.

Here, the colloidal cerium oxide refers to a dispersion system in which spherical cerium oxide having SiO ₂ as a basic unit is dispersed in a dispersion medium such as water. The amount of the dispersion medium is not particularly limited, and is usually, as a solid component in the colloidal cerium oxide, for example, 20 to 30% by mass.

The colloidal ceria used in the present invention preferably has an average particle diameter of 40 nm or less. When the average particle diameter of the colloidal ceria is within this range, the specific surface area of the Si compound precipitated in the film is further increased, and the resin adhesion is further improved.

On the other hand, the lower limit of the average particle diameter of the colloidal ceria is not particularly limited, and for example, it is preferably 5 nm or more in general flow.

The average particle diameter can be measured by the BET method (converted from the specific surface area by the adsorption method). Alternatively, it may be substituted by the average value measured by an electron microscope photograph.

The content of the Si compound in the treatment liquid of the present invention is preferably from 0.01 to 5.0 g/L, more preferably from 0.1 to 4.0 g/L, in the case of colloidal ceria.

Further, the treatment liquid of the present invention preferably contains a conductivity aid. Specifically, the conductivity promoter preferably contains an anion of a nitrate ion and at least one cation selected from the group consisting of a potassium ion, an ammonium ion, and a sodium ion.

When the treatment liquid of the present invention contains the above-mentioned electrically conductive auxiliary agent, the flow rate at which the above-mentioned coating film can be formed can be increased. That is, it is excellent in high-speed workability. This is because it is considered that the conductivity of the treatment liquid, that is, the liquid resistance is lowered by the inclusion of the conductivity aid, and the electric current is facilitated by the high-current current.

The above-mentioned conductivity aid is substantially contained in the treatment liquid of the present invention in which a salt (for example, ammonium nitrate, potassium nitrate, sodium nitrate or the like) is combined with the above-mentioned anion and the above-mentioned cationic ion, and as the content thereof, the high-speed workability is further improved. The reason for the superiority is preferably 0.1 to 10.0 g/L, more preferably 0.5 to 5.0 g/L.

Further, water is usually used as the solvent in the treatment liquid of the present invention, but an organic solvent may be used in combination.

The pH of the treatment liquid of the present invention is not particularly limited, and is preferably pH 2.0 to 5.0. If it is within this range, the treatment time can be shortened, and the stability of the treatment liquid is excellent.

The pH can be adjusted by using a known acid component (for example, phosphoric acid, sulfur Acid) ‧ alkali components (for example, sodium hydroxide, ammonia).

The treatment liquid of the present invention may contain a surfactant such as sodium lauryl sulfate or acetylene glycol as necessary. Further, the treatment liquid may contain a condensed phosphate such as pyrophosphate based on the viewpoint of the stability of adhesion behavior.

Return to the description of the film formation step again. In the film formation step, the liquid temperature of the treatment liquid at the time of the treatment is preferably 20 to 80 ° C, more preferably 40 to 60 ° C, based on the formation efficiency of the film, the uniformity of the structure, and the low cost. .

In the film formation step, the electrolytic current density at the time of performing the cathodic electrolysis treatment is preferably a low current density, more specifically, 0.05 to 7.0, for the reason that the resin adhesion and corrosion resistance of the formed film are more excellent. A/dm ² , more preferably 1.0~4.0A/dm ² . By using the treatment liquid of the present invention, a film can be formed at a low current density.

In this case, the energization time of the cathodic electrolysis treatment is stable in suppressing the decrease in the amount of adhesion, and the film can be stably formed, and the characteristics of the formed film can be further suppressed from decreasing, preferably from 0.1 to 5 seconds, preferably from 0.3 to 2. second.

Further, the electric density at the time of cathodic electrolysis treatment is preferably 0.20 to 15 C/dm ² , more preferably 0.40 to 10 C/dm ² .

After the cathodic electrolysis treatment or the like, the obtained steel sheet may be subjected to water washing treatment and/or drying in order to remove unreacted materials as necessary. The temperature and the manner of drying are not particularly limited, and for example, a general dryer or an electric furnace drying method can be applied.

The temperature during the drying treatment is preferably 100 ° C or less. The lower limit is not particularly limited, and is usually room temperature.

The steel sheet for containers of the present invention obtained by the production method of the present invention can be used for the production of various containers such as DI cans, food cans, and beverage cans.

[Examples]

Hereinafter, the present invention will be specifically described by way of examples. However, the invention is not limited thereto.

<Manufacture of tin plated steel>

A tin-plated steel sheet was produced by the following two methods [(K-1) and (K-2)].

(K-1)

The steel plate (T4 original plate) having a thickness of 0.22 mm is subjected to electrolytic degreasing and pickling, and then tin plating is applied. Then, heat-melting treatment is performed at a temperature equal to or higher than the melting point of tin, and a tin-plated layer having a Sn adhesion amount on each surface shown in the second table is formed on both surfaces of the T4 original plate. Thus, a plating layer composed of an Fe-Sn alloy layer/Sn layer in this order from the lower layer side is formed.

(K-2)

The steel plate (T4 original plate) having a thickness of 0.22 mm was electrolytically degreased, and after forming a nickel plating layer on both sides using a Watt bath with the Ni adhesion amount on each side shown in Table 2, at 10 vol.% H ₂ + 90 vol.% N ₂ Annealing at 700 ° C in the atmosphere causes the nickel plating material to diffuse and penetrate, and a Ni-Fe alloy layer (Ni containing layer) is formed on both surfaces (Ni plating amount is shown in Table 2).

Then, the steel sheet having the Ni-containing layer on the surface layer is formed by using a tin plating bath to form a plating layer of tin monomer on both surfaces of Sn on the surface shown in the second table, and then heating and melting at a melting point of Sn or higher. A tin plating layer is formed on both sides of the original T4 board. Accordingly, a plating layer composed of a Ni—Fe alloy layer/Fe—Sn—Ni alloy layer/Sn layer in this order from the lower layer side was formed.

<Formation of film>

The treatment liquid (solvent: water) having the composition shown in Table 1 was used for the steel sheet, and the cathode electrolysis treatment was carried out by the bath temperature and the electrolysis conditions (current density, energization time) shown in Table 2. Then, the obtained steel sheet was washed with water, and dried at room temperature using a hair dryer to form a film on both sides.

In addition, as the colloidal cerium oxide shown in the first table, Snowtex OXS (average particle diameter: 6 nm), Snowtex OS (average particle diameter: 10 nm), and Snowtex O (average particle diameter: 15 nm) manufactured by Nissan Chemical Industries, Ltd., Snowtex O-40 (average particle diameter: 25 nm), Snowtex OL (average particle diameter: 45 nm).

Further, the orthophosphoric acid shown in the first table is a phosphoric acid concentration of 85% by mass.

For the steel sheets to be produced, the following methods were used to evaluate the resin adhesion and corrosion resistance. The amount of each component and the evaluation results are shown together in Table 2.

Further, the P adhesion amount, the Ti adhesion amount, the Zr adhesion amount, the Si adhesion amount, and the atomic ratio of the film were measured by the above method.

<Resin Adhesion>

On both sides of the produced steel sheet for containers, a polyethylene terephthalate film was laminated by using an isophthalic acid film having a thickness of 25 μm and a copolymerization ratio of 12 mol% to form a laminated steel sheet. In the laminate, the steel sheet and the film heated to 210 ° C were held by a pair of rubber rolls to fuse the film to the steel sheet, and water-cooled within 1 sec after passing through the rubber roller. At this time, the feed speed of the steel sheet was 40 m/min, and the grip length of the rubber roller was 17 mm. Here, the long length refers to the length in the conveying direction of the portion where the rubber roller and the steel plate are in contact with each other. Moreover, the following resin adhesion property was evaluated about the laminated steel plate produced.

The evaluation of the resin adhesion was carried out by a 180-degree peeling test under a high-temperature sterilization atmosphere at a temperature of 150 ° C and a relative humidity of 100%. The 180-degree peeling test is a test piece (size: 30 mm × 100 mm) obtained by cutting a portion 3 of the steel sheet 1 in which the film 2 remains as shown in Fig. 1 (a), as shown in Fig. 1 (b). As shown in the figure, a film peeling test was carried out by adding a weight of 4 (100 g) to one end of the test piece and making a 180-degree folding back toward the film 2 side and placing it for 30 minutes. Then, the peeling length 5 shown in Fig. 1(c) was measured, and the resin adhesion was evaluated as follows. ◎, ○ or Δ indicates that the resin adhesion was good.

◎: peeling length is less than 40mm

○: peeling length of 40 mm or more and less than 45 mm

△: peeling length of 45mm or more and less than 50mm

×: peeling length of 50mm or more

<Corrosion resistance>

The epoxy phenol-based coating material was applied to both surfaces of the steel sheet for container production so as to have an adhesion amount of 50 mg/dm ² , and then baked at 210 ° C for 10 minutes to form a coating film. Then, in a beaker containing commercially available tomato juice, it was immersed at 50 ° C for 20 days to visually observe the occurrence of peeling of the coating film and the occurrence of rust, and the following evaluation was made, and ○ indicates that the corrosion resistance was good.

○: peeling and rusting of the coating film did not occur (equivalent to the chromate treated material)

×: There is peeling of the coating film, and rust is remarkably generated.

[Table 1]

[Table 2]

[table 3]

[Table 4]

As is apparent from the results shown in the above Tables 1 to 2, the examples of the present invention are excellent in resin adhesion and corrosion resistance.

In the invention examples 13 to 16 in which the Ti adhesion amount is more than 3 mg/m ² , the resin adhesion is further excellent.

Further, in the inventive examples in which the atomic ratio (Si/Zr) is in the range of 0.1 to 3.0, it is found that the resin adhesion is superior to the inventive examples 6 and 7 in which the atomic ratio (Si/Zr) is more than 3.0.

Further, in the invention examples in which the atomic ratio (P/Zr) is 0.10 or more and less than 0.50, it is found that the resin adhesion is excellent as compared with the invention examples 10, 27, 30 and 31 in which the atomic ratio (P/Zr) is 0.50 or more. The tendency.

On the other hand, in Comparative Examples 1, 2, 8, and 9 in which the Zr adhesion amount was less than 1 mg/m ² , the resin adhesion and the corrosion resistance were inferior.

Further, in Comparative Examples 3, 4, 10, and 11 in which the Ti adhesion amount was 0.5 mg/m ² or less, the resin adhesion was inferior.

Further, in Comparative Examples 5 to 7 and 12 to 14 in which the Si adhesion amount was less than 1 mg/m ² or more than 40 mg/m ² , the resin adhesion was inferior.

Further, in Comparative Examples 15 and 16 in which the P adhesion amount was less than 1 mg/m ² , the corrosion resistance was poor.

Claims (5)

A steel sheet for a container, comprising: a tin-plated steel sheet coated with a tin-plated layer on at least a part of a surface of the steel sheet; and a film disposed on a surface of the tin-plated steel sheet on a side of the tin-plated layer; wherein the film contains P, Zr, Ti, and The cerium oxide; the adhesion amount of the film on the surface of the tin-plated steel sheet in the range of 1 to 10 mg/m ² , and the adhesion amount in the Zr conversion on each side of the tin-plated steel sheet is 1 to 40 mg/m ² , The adhesion amount in terms of Ti in each of the tin-plated steel sheets is more than 0.5 mg/m ² and less than 10 mg/m ² , and the adhesion amount in terms of Si per side of the tin-plated steel sheet is 1 to 40 mg/m ² . The steel sheet for containers according to the first aspect of the invention, wherein the coating film has an adhesion amount of more than 3 mg/m ² and less than 10 mg/m ² on each side of the tin-plated steel sheet. The steel sheet for containers according to claim 1 or 2, wherein an atomic ratio (Ti/Zr) of Ti to Zr on the outermost surface opposite to the side of the tin-plated steel sheet is 0.05 to 2.0, Si and The atomic ratio (Si/Zr) of Zr is 0.1 to 3.0. The steel sheet for containers according to any one of the first to third aspects of the present invention, wherein an atomic ratio (P/Zr) of P and Zr on the outermost surface opposite to the side of the tin-plated steel sheet is 0.10 or more and less than 0.50. The steel sheet for containers according to any one of claims 1 to 4, wherein the tin-plated steel sheet is formed using a steel sheet having a nickel-containing layer on its surface.