JP5304000B2 - Steel plate for containers with excellent weldability, appearance, and can manufacturing process adhesion - Google Patents

Description

  The present invention relates to a steel plate for containers excellent in drawing ironing, weldability, corrosion resistance, paint adhesion, and film adhesion as a material for can manufacturing.

  Metal containers used for beverages and foods are roughly classified into two-piece cans and three-piece cans. A two-piece can represented by a DI can is squeezed and ironed, then painted on the inner surface of the can and painted and printed on the outer surface of the can. The three-piece can is coated on the surface corresponding to the inner surface of the can and printed on the surface corresponding to the outer surface of the can, and then the can body is welded.

  In any type of can, a coating process is indispensable before and after making the can. For painting, solvent-based or water-based paints are used, followed by baking. In this painting process, wastes (waste solvents, etc.) resulting from the paints are discharged as industrial wastes and exhaust gases (mainly carbon dioxide). Gas) is released to the atmosphere. In recent years, efforts have been made to reduce these industrial waste and exhaust gas for the purpose of protecting the global environment. Among these, the technique of laminating films as an alternative to painting has attracted attention and has spread rapidly.

  So far, in the two-piece can, there have been provided a large number of methods for producing a can in which a film is laminated and made, and related inventions. For example, a method for producing a squeezed iron cake (see Patent Document 1), a squeezed iron cake (see Patent Document 2), a method for producing a thinned deep-drawn can (see Patent Document 3), a coated steel plate for a drawn iron cake (Patent Document 4) Reference).

  In a three-piece can, a three-piece can film laminated steel strip and a manufacturing method thereof (see Patent Document 5), a steel sheet for a three-piece can (see Patent Document 6) having a multilayer organic film on the outer surface of the can, and "a striped multilayer" Examples include a steel plate for a three-piece can having an organic film (see Patent Document 7) and a method for producing a three-piece can striped laminated steel sheet (see Patent Document 8).

Japanese Patent No. 1571783 Japanese Patent No. 1670957 JP-A-2-263523 Japanese Patent No. 1601937 Japanese Patent Laid-Open No. 3-236554 JP-A-3-113494 JP-A-5-111979 JP-A-5-147181

  On the other hand, in many cases, a steel plate having a chromate film subjected to electrolytic chromate treatment is used as a steel plate used for the base of the laminate film. The chromate film has a two-layer structure, and a hydrated Cr oxide layer is present on the metal Cr layer. Therefore, the laminate film (adhesive layer in the case of a film with an adhesive) ensures adhesion to the steel sheet through the hydrated Cr oxide layer of the chromate film. Although the details of the mechanism of this adhesion development are not clarified, it is said to be a hydrogen bond between a hydroxyl group of hydrated Cr oxide and a functional group such as a carbonyl group or an ester group of a laminate film.

  From the viewpoint of reducing industrial waste and exhaust gas, the above-mentioned invention can certainly have the effect of greatly advancing the conservation of the global environment. On the other hand, in the beverage container market in recent years, PET bottles, bottles, Costs and quality competition with materials such as paper are intensifying, and for the above-mentioned laminated container steel sheets, with excellent adhesion and corrosion resistance for conventional coating applications, more Excellent can-making processability, in particular, film adhesion, processed film adhesion, corrosion resistance, and the like have been demanded.

  However, when the chromate treatment is not performed, it is expected that the corrosion resistance, paint adhesion, film adhesion, etc. will be significantly reduced. For this reason, it has been demanded that the surface of the steel plate for containers is subjected to a rust prevention treatment instead of the chromate treatment to form a rust prevention layer having good corrosion resistance, coating adhesion, film adhesion and the like.

  Therefore, the present invention has been devised in view of the above-mentioned problems, and the object of the present invention is to ensure excellent adhesion, corrosion resistance, weldability, and more excellent can manufacturing processability. It is providing the steel plate for containers excellent in the weldability, can manufacturing process, and external appearance provided with.

  As a result of intensive studies on the use of a Zr film as a new film that replaces the chromate film, the present inventors have applied a Zr film or a Zr-containing film in which a phosphate film or a phenol resin film is combined with a Zr film or a laminated film. And formed a very strong covalent bond, ensuring excellent adhesion, corrosion resistance, and weldability, and found that excellent can processability over conventional chromate films was obtained, leading to the present invention. Is.

  In addition, since tinplate having a chemical conversion treatment layer containing tin oxide and tin phosphate on the Sn plating layer is superior in paint adhesion, etc., compared to Sn plating without a chemical conversion treatment layer, it is practically limited to milk powder can applications. However, secondary adhesion and the like are insufficient, and a wide range of uses is not possible.

That is, the present invention
(1) A base Ni layer containing 5 to 150 mg / m ^{2 of} Ni formed on the steel plate surface and subjected to Ni plating or Fe—Ni alloy plating, and 300 to 3000 mg / m ² of Sn plating on the base Ni layer The island-shaped Sn formed from the unalloyed portion of the Sn plating layer by alloying a part or the whole of the base Ni layer and a part of the Sn plating layer by the molten tin treatment a plating layer, the formed above the Sn plating layer, phosphoric acid 0.5 to 5.0 / ^{m 2} as tin oxide and P of 0.3~5.0mC / cm ² as the quantity of electricity required for reduction a chemical conversion layer comprising tin, is formed on an upper layer of the chemical conversion treatment layer, Zr film of 1-500 mg / ^{m 2} of metal Zr content, the phosphate coating of 0.1-100 mg / ^{m 2} in the amount of P, C 0.1-100 mg / m ² of pheno in an amount Of Lumpur resin film has a peel film layer composed of two or more, a container for steel.
(2) Prior Symbol skin layer, Zr coating of 1-15 mg / ^{m 2} of metal Zr content, the phosphate coating of 0.1 to 15 mg / ^{m 2} in the amount of P, 0.1 to 15 mg / m in C content ^The steel plate for containers according to (1), comprising two or more of the two phenolic resin films.
(3) before Symbol skin layer, Zr coating 1~9mg / ^{m 2} of metal Zr content, the phosphate coating 0.1~8mg / ^{m 2} in the amount of P, 0.1~8mg / m in C content ^The steel plate for containers according to (2), comprising two or more of the two phenolic resin films.
(4) Sn plating of 560 to 5600 mg / m ² is applied to the surface of the steel sheet, and a Sn plating layer formed by alloying a part of the Sn plating layer by molten molten tin treatment and formed on the upper layer of the Sn plating And a chemical conversion treatment layer containing tin oxide of 0.3 to 5.0 mC / cm ² as the amount of electricity required for reduction and 0.5 to 5.0 mg / m ² of tin phosphate as the amount of P, and the chemical conversion treatment 1 to 500 mg / m ² of Zr film in the amount of metal Zr, 0.1 to 100 mg / m ² of phosphoric acid film in the amount of P, 0.1 to 100 mg / m ^{2 of} phenolic resin in the amount of C among the film has a skin layer composed of two or more, a container for steel.
(5) The Zr-containing coating layer has a metal Zr content of 1 to 15 mg / m ² , a P content of 0.1 to 15 mg / m ² , and a C content of 0.1 to 15 mg / m 2. ^The steel plate for containers according to (4), comprising two or more of the two phenolic resin films.
(6) before Symbol skin layer, Zr coating 1~9mg / ^{m 2} of metal Zr content, the phosphate coating 0.1~8mg / ^{m 2} in the amount of P, 0.1~8mg / m in C content ^The steel plate for containers according to (5), comprising two or more of the two phenolic resin films.
(7) before Symbol skin layer, characterized by being formed by a cathodic electrolysis treatment, (1) a container for steel according to any one of one to (6).
(8) before Symbol skin layer, Zr coating, the phosphoric acid coating, characterized in that it consists of three phenolic resin coating (7) for containers steel sheet according.
(9) The container steel plate according to (7) or (8), wherein the cathodic electrolysis treatment is performed in an acidic solution or an acidic solution containing tannic acid.
(10) A method for producing a container steel plate according to any one of (1) to (9), wherein the steel plate is electrolytically degreased and pickled, and then electroplated and heated and melted with tin. Then, in a phosphate aqueous solution, 1 to 20 A / dm ² , 0.1 to ² seconds of cathodic electrolysis, and then 0.2 to 5 A / dm ² and 0.1 to ² seconds of anodic electrolysis The manufacturing method of the steel plate for containers characterized by including the process of forming and forming the chemical conversion treatment layer containing a tin oxide and a tin phosphate.
It is.

  The steel sheet for laminated containers produced by the present invention has excellent can processability such as drawing and ironing, weldability, corrosion resistance, paint adhesion, film adhesion, and appearance.

  Hereinafter, the steel plate for containers excellent in weldability, can manufacturing processability, and appearance as the best mode for carrying out the present invention will be described in detail.

  The original plate used in the present invention is not particularly restricted, and usually a steel plate used as a container material is used. There are no particular restrictions on the manufacturing method and material of the original plate, and the steel plate surface is manufactured from the normal steel slab manufacturing process through hot rolling, pickling, cold rolling, annealing, temper rolling, and the like. Is provided with a metal surface treatment layer. There is no particular restriction on the method of granting. For example, a known technique such as an electroplating method, a vacuum deposition method, or a sputtering method may be used, or a heat treatment for providing a diffusion layer may be combined.

As one embodiment of the metal surface treatment layer of the present invention, a Ni plating layer containing 5 to 150 mg / m ^{2 of} Ni or a base Ni layer plated with Fe—Ni alloy is formed on the steel sheet surface, and 300 to 300 is formed thereon. 3000 mg / m ² of Sn plating is performed, and a part or all of the underlying Ni layer and part of the Sn plating layer are alloyed by a molten tin treatment to form an island-shaped Sn plating layer.

The purpose of performing Ni-based plating of Ni or Fe—Ni alloy plating on the steel sheet to provide a base Ni layer is to ensure corrosion resistance. Since Ni is a highly corrosion-resistant metal, the corrosion resistance of the alloy layer formed during the molten tin treatment can be improved by plating Ni on the surface of the steel sheet. The effect of improving the corrosion resistance of the alloy layer by Ni starts to appear when the amount of Ni to be plated starts from 5 mg / m ² or more, so the Ni amount needs to be 5 mg / m ² or more. As the amount of Ni increases, the effect of improving the corrosion resistance of the alloy layer increases. However, when the amount of Ni exceeds 150 mg / m ² , the improvement effect is saturated. Moreover, since Ni is an expensive metal, it is economically disadvantageous to plate 150 mg / m ² or more of Ni. Therefore, the amount of Ni needs to be ⁵ to 150 mg / m ² .

  In addition, when Ni diffusion plating is performed, after Ni plating, diffusion treatment is performed in an annealing furnace to form a Ni diffusion layer. However, the present invention can be performed even before or after or simultaneously with the Ni diffusion treatment. The effect of Ni as the Ni-based plating layer and the effect of the nitriding layer can be obtained. About the method of Ni plating and Fe-Ni alloy plating, you may make it use the well-known method generally performed by the electroplating method.

Sn plating is performed after the Ni-based plating. Sn plating here is plating using metal Sn, but inevitable impurities may be mixed, and trace elements may be added. The Sn plating method is not particularly limited, and a known electroplating method, a method of plating by immersing in molten Sn, or the like may be used. The purpose of Sn plating is to ensure corrosion resistance and weldability. Since Sn itself has high corrosion resistance, it exhibits excellent corrosion resistance both as metal Sn and as an alloy Sn formed by the molten tin treatment described below. The excellent corrosion resistance of Sn is remarkably improved from 300 mg / m ² or more, and the corrosion resistance is improved as the Sn plating amount is increased, but the effect is saturated when it is 3000 mg / m ² or more. Therefore, the Sn plating amount is desirably 3000 mg / m ² or less from an economical viewpoint.

In addition, Sn with low electric resistance is soft and spreads by pressurizing Sn between the electrodes during welding, so that a stable energization region can be secured, and thus particularly excellent weldability is exhibited. This excellent weldability is exhibited if the amount of metal Sn is 100 mg / m ² or more. Moreover, if it is the range of Sn plating amount of this invention, it is not necessary to prescribe | regulate the upper limit of metal Sn amount. Therefore, from the above two points, the Sn plating amount is limited to the range of 300 to 3000 mg / m ² .

  After Sn plating, molten tin treatment is performed. The purpose of the molten tin treatment is to melt Sn and alloy it with an underlying steel plate or an underlying metal to form an Sn—Fe or Sn—Fe—Ni alloy layer to improve the corrosion resistance of the alloy layer and to form island-shaped Sn. Is to form. A steel plate having a plating structure in which island-shaped Sn is formed by controlling the molten tin treatment, and a coating layer in which metal Sn is not present and an Fe—Ni or Fe—Ni—Sn alloy plating layer having excellent film adhesion is exposed; can do.

Moreover, as another form in the metal surface treatment layer of this invention, Sn plating of 560-5600 mg / m < ² > is given to the steel plate surface, and a part of Sn plating layer is alloyed by a molten tin process. . Sn has excellent workability, excellent weldability, and corrosion resistance, but Sn plating alone requires 560 mg / m ² or more from the viewpoint of corrosion resistance. The corrosion resistance improves as the Sn plating amount increases, but the effect is saturated when the Sn plating amount is 5600 mg / m ² or more. Therefore, the Sn plating amount is desirably 5600 mg / m ² or less from an economical viewpoint. Further, by performing molten tin treatment after Sn plating, an Sn alloy layer is formed and the corrosion resistance is further improved.

  Here, the amount of metallic Ni and the amount of metallic Sn in the base Ni layer and Sn plating layer can be measured, for example, by the fluorescent X-ray method. In this case, a calibration curve related to the amount of metal Ni is specified in advance using a sample of the amount of deposited Ni that has a known amount of metal Ni, and the amount of metal Ni is relatively specified using this calibration curve. Similarly, in the case of the amount of metal Sn, a calibration curve related to the amount of metal Sn is specified in advance using a sample of the amount of Sn deposited with a known amount of metal Sn, and the amount of metal Sn is specified relatively using this calibration curve. To do.

An upper layer of Sn treated with molten tin is charged with 0.3 to 5.0 mC / cm ² of tin oxide as an amount of electricity required for reduction and 0.5 to 5.0 mg / m ² of tin phosphate as an amount of P. Zr-containing film containing two or more of Zr film, phosphoric acid film, and phenolic resin film, which is the essence of the present invention, on the chemical conversion treatment layer, and further on the metal surface chemical conversion treatment layer. Is granted.

  The chemical conversion treatment film will be described in detail below.

First, the chemical conversion treatment layer composed of tin oxide and tin phosphate formed in the upper layer of Sn subjected to the molten tin treatment will be described. The amount of tin oxide in this layer needs to be 0.3 to 5.0 mC / cm ² as the amount of electricity required for reduction. The amount of electricity required for the reduction of the tin oxide layer is a constant value of 0.05 mA / cm ² in a 0.001 mol / L hydrobromic acid aqueous solution obtained by removing dissolved oxygen from a tin-plated steel sheet by means such as bubbling of nitrogen gas. Cathodic electrolysis with current can be obtained from the obtained potential-time curve. When the amount of electricity required for the reduction of the tin oxide layer is less than 0.3 mC / cm ^{2 or} more than 5.0 mC / cm ² , the secondary adhesion of the organic film is lowered. From the viewpoint of securing the secondary adhesion of the organic film, a more preferable range of the tin oxide layer amount is 0.5 to 5.0 mC / cm ² . A more preferable range is 1.0 to 5.0 mC / cm ² , and within this range, a thin tin-plated steel sheet having extremely good corrosion resistance after coating and corrosion resistance after lamination is obtained.

The tin phosphate in the chemical conversion treatment layer composed of tin oxide and tin phosphate needs to be 0.5 to 5.0 mg / m ² as the amount of P. Even if the amount of P is less than 0.5 mg / m ² , the primary adhesion of the organic film can be secured, but the secondary adhesion cannot be secured. On the other hand, tin phosphate exceeding 5.0 mg / m ² as the amount of P is likely to cohesively break, and thus cannot secure primary adhesion and secondary adhesion of the organic film.

  Next, a film composed of two or more of Zr film, phosphoric acid film and phenol resin film formed on the upper layer will be described.

The role of the Zr film is to ensure corrosion resistance and adhesion. The Zr coating is composed of a Zr compound such as Zr oxide, hydroxide Zr, Zr fluoride, Zr phosphate, or a composite coating thereof, and these Zr compounds have excellent corrosion resistance and adhesion. Therefore, when the Zr film increases, the corrosion resistance and adhesion start to improve, and when the amount of metal Zr is 1 mg / m ² or more, practically satisfactory levels of corrosion resistance and adhesion are secured. Furthermore, when the amount of Zr film increases, the effect of improving corrosion resistance and adhesion also increases. However, when the amount of Zr film exceeds 500 mg / m ^{2 in} terms of metal Zr, the Zr film becomes too thick and the adhesion of the Zr film itself deteriorates. In addition, the electrical resistance increases and the weldability deteriorates. Therefore, the amount of Zr film needs to be ¹ to 500 mg / m ² in terms of metal Zr.

Further, if the amount of Zr film exceeds 15 mg / m ² in terms of metal Zr, uneven adhesion of the film may appear as appearance unevenness. Therefore, the amount of Zr film is more preferably ¹ to 15 mg / m in terms of metal Zr. a m ^2. Furthermore, in order to better stabilize the appearance unevenness, the Zr film amount is preferably 1 to 9 mg / m ² in terms of metal Zr amount.

The role of the phosphate film is to ensure corrosion resistance and adhesion. The phosphate film is composed of a film such as Fe phosphate, Sn phosphate, Ni phosphate, Zr phosphate, phosphate-phenol resin film or a composite film of these formed by reacting with the base. The phosphoric acid film has excellent corrosion resistance and adhesion. Therefore, when the phosphoric acid film increases, the corrosion resistance and adhesion begin to improve, and when the P amount is 0.1 mg / m ² or more, a practically satisfactory level of corrosion resistance and adhesion are secured. Furthermore, when the amount of phosphoric acid film increases, the effect of improving corrosion resistance and adhesion also increases, but when the amount of phosphoric acid film exceeds 100 mg / m ² in terms of P amount, the phosphoric acid film becomes too thick and adhesion of the phosphoric acid film itself is increased. As a result, the electrical resistance increases and the weldability deteriorates. Therefore, the amount of phosphoric acid film needs to be 0.1 to 100 mg / m ² in terms of P amount.

Further, if the amount of phosphoric acid film exceeds 15 mg / m ² in terms of P, uneven adhesion of the film may appear as appearance unevenness. Therefore, the amount of phosphoric acid film is more preferably 0.1 to 15 mg in terms of P amount. / M ² . Furthermore, in order to better stabilize the appearance unevenness, the phosphoric acid film amount is preferably 0.1 to 8 mg / m ² in terms of P amount.

The role of the phenolic resin film is to ensure adhesion. Since the phenol resin itself is an organic substance, it has excellent adhesion to paints and laminate films. Therefore, when the phenol resin film increases, the adhesion begins to improve, and when the C amount is 0.1 mg / m ² or more, a practically satisfactory level of adhesion is secured. Furthermore, when the amount of the phenol resin film increases, the effect of improving the adhesion also increases. However, when the amount of the phenol resin film exceeds 100 mg / m ² in terms of the C amount, the electrical resistance increases and the weldability deteriorates. Therefore, the phenol resin film amount needs to be 0.1 to 100 mg / m ² in terms of C amount.

Further, if the amount of the phenol resin film exceeds 15 mg / m ² in terms of C, uneven adhesion of the film may appear as appearance unevenness, and therefore the amount of phenol resin film is more preferably 0.1 to 15 mg in terms of C. / M ² . Furthermore, in order to better stabilize the appearance unevenness, the amount of the phenol resin film is preferably 0.1 to 8 mg / m ² in terms of C.

  Even if the Zr film, the phosphoric acid film, and the phenol resin film as described above are used alone, only a certain degree of effect is recognized and they do not have sufficient practical performance. However, a film obtained by combining two or more of a Zr film, a phosphoric acid film, and a phenol resin film exhibits excellent practical performance. In addition, when the Zr film is combined with one or more of a phosphoric acid film or a phenol film, a further excellent practical performance is exhibited. Furthermore, in a range where the amount of the film is small, a film composed of three kinds of Zr film, phosphoric acid film, and phenol resin film is more stable in practical performance in order to complement each characteristic.

  Further, the amount of metal Zr and the amount of P contained in the Zr-containing coating layer according to the present embodiment can be measured by a quantitative analysis method such as fluorescent X-ray analysis, for example. On the other hand, the amount of C can be measured by subtracting the amount of C existing in the steel sheet using a TOC (total organic carbon meter).

  Furthermore, the structure of the Zr-containing coating layer according to the present embodiment is specified from the result of the composition state analysis including the depth direction analysis of the Zr-containing coating layer by, for example, X-ray photoelectron spectroscopy (XPS). can do.

  Next, a method for forming a film will be described.

  First, a method of applying a chemical conversion treatment film composed of tin oxide and tin phosphate formed on the upper layer of Sn that has been subjected to molten tin treatment will be described. The most suitable method for applying the coating is a method of cathodic electrolysis in an aqueous phosphate solution and then an anodic electrolysis in the same solution. The treatment solution has good results at pH 2 to 3 (good primary adhesion and secondary adhesion of the organic film). In this pH range, the chemical species of phosphoric acid in the phosphate aqueous solution is mainly Among phosphoric acid and dihydrogen phosphate ions, Na, Sn, Al, Mg, and Ca are preferred as counter cations of dihydrogen phosphate ions without affecting the electrolytic treatment. Na, Sn, Al, Mg, and Ca cations may be present alone or in combination of two or more. The total concentration of phosphoric acid is suitably in the range of 5 to 80 g / L in terms of phosphoric acid and a liquid temperature of 25 to 60 ° C.

Cathodic electrolysis is a step of reducing tin oxide that inhibits the adhesion of the organic film, which occurs on the surface of the tin-plated steel sheet by molten tin treatment, and the cathode current density of the cathodic electrolysis is 1 to 20 A / dm ^2. The electrolysis time is preferably 0.1 to 2 seconds. When the cathode current density is lower than 1 A / dm ^2, tin oxide generated by the molten tin treatment cannot be sufficiently reduced, and it is difficult to obtain good organic film adhesion. On the other hand, even if the cathode current density is higher than 20 A / dm ² , only the amount of hydrogen gas generated on the cathode surface increases, and no improvement in the adhesion of the organic film is observed. When the cathodic electrolysis time is shorter than 0.1 seconds, tin oxide generated by the molten tin treatment cannot be sufficiently reduced, and good organic film adhesion is difficult to obtain. On the other hand, tin oxide generated by the molten tin treatment is almost reduced by the cathodic electrolysis treatment within 2 seconds. Therefore, even if the tin oxide is made longer than this, no improvement in performance such as adhesion of the organic film is observed.

Anodic electrolytic treatment produces tin oxide on the surface of metallic tin that appears as a result of reduction by cathodic electrolytic treatment. At the same time, tin is dissolved slowly and bonded to phosphate ions in the treatment solution to give tin phosphate. It is a process to do. The tin oxide produced by the anodic electrolytic treatment is considered to have a qualitative difference from the tin oxide produced by the molten tin treatment, and does not inhibit the adhesion of the organic film. The anode current density of the anodic electrolysis treatment is suitably 0.2 to 5 A / dm ² , and the electrolysis time is suitably 0.1 to ² seconds. If the anode current density is lower than 0.2 A / dm ² , the dissolution of surface tin is insufficient, and it takes time to obtain a sufficient amount of tin phosphate to ensure the secondary adhesion of the organic film. Not practical. On the other hand, when the anode current density exceeds 5 A / dm ² , the dissolution of surface tin is too fast and sparse and brittle tin phosphate is generated, and the cohesive failure of this layer significantly deteriorates the adhesion of the organic film. When the electrolysis time is shorter than 0.1 seconds, the adhesion amount of P is insufficient, and sufficient secondary paint adhesion and corrosion resistance cannot be obtained. On the other hand, if the electrolysis time is longer than 2 seconds, the tin oxide layer becomes thick, and the primary paint adhesion, the secondary paint adhesion and the corrosion resistance deteriorate.

  Next, a method for applying a film composed of two or more of Zr film, phosphoric acid film and phenol resin film formed on the upper layer will be described.

  Methods for applying these films include a method of immersing a steel plate in an acidic solution in which Zr ions, phosphate ions, and low molecular weight phenolic resins are dissolved, and a method of performing cathodic electrolysis. Since various films are formed by etching, the adhesion becomes non-uniform, and the processing time becomes longer, which is disadvantageous for industrial production. On the other hand, in the cathode electrolysis treatment, a uniform film can be treated for a short time of several seconds to several tens of seconds, combined with forced charge transfer, surface cleaning by hydrogen generation at the steel plate interface, and adhesion promotion effect due to pH increase. Therefore, it is extremely advantageous industrially. Therefore, cathodic electrolytic treatment is desirable for providing the Zr film, phosphoric acid film, and phenol resin film of the present invention.

The bath composition of the cathodic electrolysis treatment is 0.3 to 60 g of low molecular weight phenol resin having a Zr ion of 0.3 to 6.0 g / L, a phosphate ion of 0.3 to 20 g / L, and a mass average molecular weight of about 5000. / L is desirable. Cathodic electrolytic treatment conditions are preferably a current density of 0.5 to 40 A / dm ² , a solution time of 0.1 to 5 seconds, and a bath temperature of 10 to 70 ° C., and further considering the industrial productivity, the current density of 1 to 5 A. / Dm ² , electrolysis time of 0.1 to ² , and bath temperature of 20 to 40 ° C. are preferable.

  In addition, when tannic acid is added to an acidic solution used for immersion treatment or cathodic electrolysis, tannic acid is combined with Fe, and a film of Fe tannic acid is formed on the surface, thereby improving rust resistance and adhesion. Therefore, depending on the application, the treatment may be performed in a solution to which tannic acid is added. A range in which 0.3 to 5.0 g / L of tannic acid is further included in the above-described cathode electrolytic treatment bath is desirable.

  Examples and Comparative Examples of the present invention are described below, and the conditions and results are shown in Tables 1 to 3.

A surface treatment layer was formed on a steel plate having a thickness of 0.17 to 0.23 mm using the following treatment methods (1) to (3).
(1) After cold rolling, the annealed and pressure-regulated original sheet is degreased, pickled, plated with Sn using a ferrostan bath, and then subjected to molten tin treatment to prepare an Sn-plated steel sheet having an Sn alloy layer Produced.
(2) After cold rolling, the annealed and pressure-adjusted original plate is degreased, pickled, then subjected to Fe-Ni alloy plating using a sulfuric acid-hydrochloric acid bath, and subsequently subjected to Sn plating using a ferrostan bath, Then, a molten tin treatment was performed to produce a Ni and Sn plated steel sheet having a Sn alloy layer.
(3) After cold rolling, Ni plating is performed using a watt bath, a Ni diffusion layer is formed during annealing, degreasing, pickling, Sn plating using a ferrostan bath, and then molten tin treatment. Then, a Ni and Sn plated steel sheet having a Sn alloy layer was produced.

After the surface treatment layer is formed by the above treatments (1) to (3), a chemical conversion treatment layer is formed thereon by the treatment method (4), and the treatments (5) to (13) are further formed thereon. A Zr film, a phosphoric acid film, and a phenol resin film were formed by the method.
(4) Cathodic electrolysis treatment in a treatment solution having a total phosphoric acid concentration of 35 g / L in terms of phosphoric acid, pH 2.5 containing a counter cation of 4 g / L, and a liquid temperature of 40 ° C., and then anodic electrolysis treatment in the same solution gave.
(5) The steel sheet was immersed in a treatment solution in which fluorinated Zr, phosphoric acid, and a phenol resin were dissolved, and after cathodic electrolysis, dried to form a Zr film, a phosphoric acid film, and a phenol resin film.
(6) The steel sheet was immersed in a treatment solution in which phosphoric acid and a phenol resin were dissolved, and after cathodic electrolysis, it was dried to form a phosphoric acid film and a phenol resin film.
(7) The steel sheet was immersed in a treatment solution in which Zr fluoride and phosphoric acid were dissolved, and after cathodic electrolysis, dried to form a Zr film and a phosphoric acid film.
(8) The steel sheet was immersed in a treatment solution in which Zr fluoride and a phenol resin were dissolved, and after cathodic electrolysis, dried to form a Zr film and a phenol resin film.
(9) The steel sheet was immersed in a treatment solution in which fluorinated Zr, phosphoric acid, and tannic acid were dissolved, and after cathodic electrolysis, dried to form a Zr film and a phosphoric acid film.
(10) The steel sheet was immersed in a treatment solution in which Zr fluoride, phosphoric acid, and phenol resin were dissolved, and dried to form a Zr film, a phosphoric acid film, and a phenol resin film.
(11) The steel sheet was immersed in a treatment solution in which phosphoric acid and a phenol resin were dissolved, and dried to form a phosphoric acid film and a phenol resin film.
(12) The steel sheet was immersed in a treatment solution in which Zr fluoride and phosphoric acid were dissolved, and dried to form a Zr film and a phosphoric acid film.
(13) The steel sheet was immersed in a treatment solution in which Zr fluoride and phenol resin were dissolved, and dried to form a Zr film and a phenol resin film.

In addition, when forming the chemical conversion treatment layer of the Example of this invention shown in Table 1-Table 2, and a comparative example, it is 1-20 A / dm < ² >, 0.1-2 second cathodic electrolysis process in the phosphate aqueous solution. Then, anodic electrolytic treatment of 0.2 to 5 A / dm ² and 0.1 to ² seconds was performed to form a chemical conversion treatment layer containing tin oxide and tin phosphate.

About the test material which performed said process, performance evaluation was performed about each item of (A)-(H) shown below.
(A) Workability A 20 μm thick PET film is laminated on both sides of the test material at 200 ° C., and the can making process by drawing and ironing is performed in stages, and the wrinkles, floats, and peeling of the film are observed. There are 4 stages of molding from the area ratio (◎: No film wrinkling, floating, peeling, ○: Area ratio of film wrinkling, floating, peeling is 0 to 0.5%, Δ: Film wrinkling, floating, peeling Area ratio of 0.5 to 15%, x: the area ratio of film wrinkles, floats, and peeling exceeds 15% or breaks and cannot be processed).
(B) Weldability Using a wire seam welder, the current is changed under the conditions of a welding wire speed of 80 m / min, and the test material is welded. Judging comprehensively from the width of the appropriate current range consisting of the maximum current value at which the welding defects of the steel become conspicuous, 4 stages (◎: secondary current current range: 1500 A or more, ○: secondary current proper current range : 800 A or more and less than 1500 A, Δ: secondary current appropriate current range: 100 A or more and less than 800 A, x: secondary current proper current range: less than 100 A), and the weldability was evaluated.
(C) Film adhesion A 20 μm thick PET film is laminated on both sides of the test material at 200 ° C., drawn and ironed to produce a can, and subjected to a retort treatment at 125 ° C. for 30 min. The peeled area ratio was observed in four stages (◎: peeled area ratio: 0%, ○: peeled area ratio of more than 0% to 2%, Δ: peeled area ratio: more than 2% to 10%, x: peeled Area ratio: more than 10%).
(D) Paint adhesion After applying epoxy-phenolic resin to the test material and baking it at 200 ° C for 30 minutes, put the grain of the depth reaching the iron core at intervals of 1 mm, peel it off with tape, and observe the peeling situation From the peeled area ratio, four stages (◎: peeled area ratio: 0%, ○: peeled area ratio over 0% to 5%, Δ: peeled area ratio: over 5% to 30%: x: peeled area ratio : More than 30%).
(E) Corrosion resistance After applying an epoxy-phenol resin to the test material and baking it at 200 ° C. for 30 minutes, a cross cut with a depth reaching the base iron is added, and a 1.5% citric acid-1.5% salt mixed solution Dipping in a test solution consisting of 72 ° C. for 72 hours, washing, drying, tape peeling, observing the corrosion condition under the coating film in the cross-cut portion and the corrosion condition in the flat plate portion, From both evaluations of the corrosion area rate of the flat part, 4 stages (◎: Under-coating corrosion width less than 0.2 mm and flat part corrosion area rate of 0%, ○: Under-coating corrosion width of 0.2 to less than 0.3 mm And the corrosion area ratio of the flat part is more than 0% to 1%, Δ: the corrosion width under the coating film is less than 0.3 to 0.45 mm, and the corrosion area ratio of the flat part is more than 1% to 5%, ×: the corrosion width under the coating film Evaluation was made based on a judgment of 0.45 mm or more than 5% of the corrosion area of the flat portion.
(F) Rust resistance The test material is left in an atmosphere of repeated dry and wet conditions (humidity 90%, 2hr⇔humidity 40%, 2hr) for 2 months, and the rust generation status is observed. A: Rust generation area ratio 0%, B: Rust generation area ratio 0% to 1%, Δ: Rust generation area ratio 1% to 5%, X: Rust generation area ratio 5%).
(G) Appearance Visual observation of test material, Zr film, phosphoric acid film, phenol resin film unevenness occurrence in 5 stages (◎: No unevenness, ◎: Very slight unevenness to the extent that there is no practical problem , ○: slight unevenness, Δ: unevenness, x: significant unevenness).
(H) Island-like Sn situation The surface of the island-like Sn situation when Sn plating was performed after Ni-based plating was observed with an optical microscope. △: there is a part where no island is formed, x: no island is formed).
The amount of coating was determined by quantitative analysis with X-ray fluorescence for the amounts of Zr and P, and the amount of C was determined by the total carbon content measurement method.

  In this table, Examples 1-1 to 1-32, 2-1 to 2-30, and 3-1 to 3-69 satisfy the conditions defined in the present invention. On the other hand, Comparative Examples 1-1 to 1-12, 2-1 to 2-11, and 3-1 to 3-18 all deviate from the conditions defined in the present invention. In Examples 1-1 to 1-32, 2-1 to 2-30, and 3-1 to 3-69, good evaluation results were obtained in all the evaluation items (A) to (G). It was. On the other hand, Comparative Examples 1-1 to 1-12, 2-1 to 2-11, and 3-1 can obtain good evaluation results in all the evaluation items (A) to (G). could not. Further, from the above table, it can be seen that formation of island-shaped Sn is effective for the test material with a small amount of Sn adhesion in order to ensure weldability. In addition, the weldability is good in the test material having a large amount of Sn adhesion.

As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

Claims (10)

A base Ni layer containing 5 to 150 mg / m ^{2 of} Ni formed on a steel plate surface and subjected to Ni plating or Fe—Ni alloy plating;
300 to 3000 mg / m ² of Sn plating is applied on the base Ni layer, and a part or all of the base Ni layer and a part of the Sn plating layer are alloyed by molten tin treatment to form the Sn. An island-shaped Sn plating layer formed from the non-alloyed portion of the plating layer;
It is formed in the upper layer of the Sn plating layer, and contains 0.3 to 5.0 mC / cm ² of tin oxide as the amount of electricity required for reduction and 0.5 to 5.0 mg / m ² of tin phosphate as the amount of P. A chemical conversion treatment layer;
Formed in the upper layer of the chemical conversion treatment layer, 1 to 500 mg / m ² of Zr film in the amount of metal Zr, 0.1 to 100 mg / m ² of phosphoric acid film in the amount of P, 0.1 to 100 mg / m in the amount of C of the ^two phenolic resin film, a skin film layer composed of two or more,
A steel plate for containers. Prior Symbol skin layer, Zr coating of 1-15 mg / ^{m 2} of metal Zr content, the phosphate coating of 0.1 to 15 mg / ^{m 2} in the amount of P, phenol 0.1 to 15 mg / ^{m 2} in C content The steel plate for containers according to claim 1, comprising two or more types of resin films. Prior Symbol skin layer, Zr coating 1~9mg / ^{m 2} of metal Zr content, the phosphate coating 0.1~8mg / ^{m 2} in the amount of P, phenol 0.1~8mg / ^{m 2} in C content The steel plate for containers according to claim 2, comprising two or more kinds of resin films. A Sn plating layer formed by alloying a part of the Sn plating layer by subjecting the surface of the steel sheet to Sn plating of 560 to 5600 mg / m ² , and molten tin processing,
Chemical conversion formed on the upper layer of the Sn plating and containing 0.3 to 5.0 mC / cm ² of tin oxide as the amount of electricity required for reduction and 0.5 to 5.0 mg / m ² of tin phosphate as the amount of P Processing layer,
Formed in the upper layer of the chemical conversion treatment layer, 1 to 500 mg / m ² of Zr film in the amount of metal Zr, 0.1 to 100 mg / m ² of phosphoric acid film in the amount of P, 0.1 to 100 mg / m in the amount of C of the ^two phenolic resin film, a skin film layer composed of two or more,
A steel plate for containers. Prior Symbol skin layer, Zr coating of 1-15 mg / ^{m 2} of metal Zr content, the phosphate coating of 0.1 to 15 mg / ^{m 2} in the amount of P, phenol 0.1 to 15 mg / ^{m 2} in C content The steel plate for containers according to claim 4, comprising two or more of the resin films. Prior Symbol skin layer, Zr coating 1~9mg / ^{m 2} of metal Zr content, the phosphate coating 0.1~8mg / ^{m 2} in the amount of P, phenol 0.1~8mg / ^{m 2} in C content The steel plate for containers according to claim 5, comprising two or more kinds of resin films. Prior Symbol skin layer, characterized by being formed by a cathodic electrolysis treatment, container steel sheet according to any one of claims 1 to 6. Prior Symbol skin layer, Zr coating, the phosphoric acid coating, characterized in that it consists of three phenolic resin film, container steel sheet according to claim 7 wherein.   The steel plate for containers according to claim 7 or 8, wherein the cathodic electrolysis is performed in an acidic solution or an acidic solution containing tannic acid. A method for producing the steel plate for containers according to any one of claims 1 to 9,
After electrolytically degreasing and pickling the steel plate, electrotin plating, and heating and melting treatment of tin, in a phosphate aqueous solution, 1-20 A / dm ² , 0.1-2 seconds of cathodic electrolytic treatment, Next, a container comprising a step of forming a chemical conversion treatment layer containing tin oxide and tin phosphate by performing an anodic electrolytic treatment of 0.2 to 5 A / dm ² for 0.1 to ² seconds. Steel plate manufacturing method.