JP4886811B2 - Steel plate for containers excellent in organic film performance and method for producing the same - Google Patents

Description

  In particular, 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, and a method for producing the same.

  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 canning. Solvent-based or water-based paints are used for painting, followed by baking. In this painting process, waste (such as waste solvents) resulting from the paint is discharged as industrial waste, and exhaust gas (mainly Carbon dioxide) 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 drawn iron cake (Patent Document 1)”, “a drawn iron cake (Patent Document 2)”, “a method for producing a thinned deep drawn can (Patent Document 3)”, “coated steel sheet for drawn iron cake” (Patent Document 4) ".

  Further, in the three-piece can, “film laminated steel strip for three-piece can and manufacturing method thereof (Patent Document 5)”, “for three-piece can having a multilayer organic film on the outer surface of the can (Patent Document 6)”, “stripe-shaped can And “three-piece can steel sheet having a multilayer organic coating (Patent Document 7)” and “three-piece can striped laminated steel sheet manufacturing method (Patent Document 8)”.

  On the other hand, in many cases, a chromate film subjected to electrolytic chromate treatment is used for a steel sheet used as a base of a 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.

Japanese Patent No. 1571783 Japanese Patent No. 1670957 JP-A-2-263523 Japanese Patent No. 1601937 Japanese Patent Laid-Open No. 3-236554 Japanese Patent Laid-Open No. 05-124648 JP-A-5-111979 JP-A-5-147181

  Although the above-mentioned invention certainly has the effect of greatly advancing the conservation of the global environment, on the other hand, in the beverage container market, cost and quality competition with materials such as PET bottles, bottles and paper have intensified in recent years. In addition, for the above-mentioned steel sheet for laminated containers, it is possible to achieve superior can-making processability, especially film adhesion, while ensuring excellent adhesion and corrosion resistance for the conventional coating application. , Processed film adhesion, corrosion resistance, etc. have come to be required.

  In recent years, mainly in Europe and the United States, restrictions on the use of hazardous substances such as lead and cadmium and consideration of the working environment of manufacturing plants have begun to be sought, and there is a demand for a film that does not use chromate and does not impair can manufacturing. It came to be able to.

  Therefore, the present invention has been made in view of such problems, and its purpose is to have excellent canning processability and excellent drawing ironing, weldability, corrosion resistance, paint adhesion, and film adhesion. It is providing the steel plate for containers which has these, and its manufacturing method.

  As a result of intensive studies on the use of a Zr compound film as a new film to replace the chromate film, the present inventors have applied a Zr compound film or a Zr film obtained by combining a Zr compound film with a phosphate film or a phenol resin film. Forms a very strong covalent bond with the laminate film, resulting in superior can processability over conventional chromate coatings, as well as excellent drawing and ironing, weldability, corrosion resistance, paint adhesion, and film adhesion It has been found that it is obtained, and the present invention has been achieved.

That is, the present invention
(1) It has a Zr compound film formed on a steel plate by performing immersion or electrolytic treatment in a solution containing Zr ions, F ions, ammonium ions, and nitrate ions, and the adhesion amount of the Zr compound film is A steel plate for containers, characterized in that the amount of metal Zr is 1 to 100 mg / m ² and the amount of F is 0.1 mg / m ² or less.
(2) The container according to (1), wherein the solution further contains phosphate ions, and the adhesion amount of the Zr compound film is 0.1 to 50 mg / m ² in terms of P amount. Steel plate.
(3) The solution further contains a phenol resin,
The Zr compound film further has a phenol resin film,
The steel plate for containers according to (2), wherein the adhesion amount of the phenol resin film is 0.1 to 50 mg / m ² in terms of C amount.
(4) The steel sheet is a surface-treated steel sheet having a surface treatment layer containing Ni of 10 to 1000 mg / m ² or Sn of 100 to 15000 mg / m ² on at least one side. The steel plate for containers according to any one of (3).
(5) After forming the Zr compound film in the solution according to any one of (1) to (3) , washing with warm water at 40 ° C. or higher for 0.5 seconds or longer is performed by immersion treatment or spray treatment. The manufacturing method of the steel plate for containers characterized by performing a process.
It is.

  The steel sheet for laminated containers excellent in can manufacturing process produced by the present invention has excellent drawing ironing, weldability, corrosion resistance, paint adhesion, and film adhesion.

  Hereinafter, a steel plate for containers excellent in can manufacturing processability 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 original plate is manufactured through normal steel slab manufacturing processes such as hot rolling, pickling, cold rolling, annealing, and temper rolling. A surface treatment layer containing one or more of Ni and Sn is applied to the original plate, but the method of applying is not particularly limited. For example, a known technique such as an electroplating method, a vacuum deposition method, or a sputtering method may be used, and a heat treatment may be combined after plating in order to provide a diffusion layer. Further, even if Ni is plated with Fe—Ni alloy, the essence of the present invention is not changed.

In the surface treatment layer containing one or more of Ni and Sn thus applied, Ni is preferably in the range of 10 to 1000 mg / m ² as metal Ni and Sn is in the range of 100 to 15000 mg / m ² as metal Sn. .

Sn exhibits excellent workability, weldability, and corrosion resistance, and it is necessary that 100 mg / m ² or more of metal Sn is exhibited as the effect. In order to ensure sufficient weldability, it is desirable to apply 200 mg / m ² or more, and in order to ensure sufficient workability, it is desirable to apply 1000 mg / m ² or more. As the Sn adhesion amount increases, the excellent workability and weldability improvement effects of Sn increase, but at 15000 mg / m ² or more, the corrosion resistance improvement effect is saturated, which is economically disadvantageous. Therefore, it is preferable that the adhesion amount of Sn is 15000 mg / m ² or less as metal Sn. Moreover, a Sn alloy layer is formed by performing a reflow process after Sn plating, and corrosion resistance further improves.

Ni exerts its effects on paint adhesion, film adhesion, corrosion resistance, and weldability. For this purpose, Ni of 10 mg / m ² or more is necessary as metal Ni. With an increase in the amount of Ni deposited, the improvement effect of excellent film adhesion, corrosion resistance, and weldability of Ni increases. However, if it is 1000 mg / m ² or more, the improvement effect is saturated, which is economically disadvantageous. Therefore, the adhesion amount of Ni is preferably 10 mg / m ² or more and 1000 mg / m ² or less as metal Ni.

  Here, the amount of metallic Ni and the amount of metallic Sn in the surface treatment layer can be measured by, for example, a 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.

  A Zr compound film or a composite film of a Zr compound and a phenol resin, which is the essence of the present invention, is applied to the upper layer of the surface treatment layer containing one or more of these Ni and Sn. Methods for applying these films include a method of immersing a steel sheet in an acidic solution in which Zr ions, phosphate ions, F ions, and low molecular phenol resins are dissolved, and a method of performing cathodic electrolysis. However, the immersion treatment is disadvantageous in industrial production because the base is etched to form various films, resulting in non-uniform adhesion and a longer treatment time. On the other hand, in the cathodic electrolysis treatment, a uniform film can be obtained in combination with forced charge transfer, surface cleaning by hydrogen generation at the steel plate interface, and adhesion promoting effect by pH increase. Further, in this cathodic electrolysis treatment, a Zr oxide, Zr excellent in the effect of improving the corrosion resistance and adhesion for a short time of about several seconds to several tens of seconds due to the coexistence of nitrate ions and ammonium ions in the treatment liquid. Since it is possible to promote the precipitation of the Zr compound film containing phosphorus oxide, it is extremely advantageous industrially. Therefore, cathodic electrolysis is desirable for applying the Zr film of the present invention, and in particular, cathodic electrolysis with a treatment liquid in which nitrate ions and ammonium ions coexist is necessary.

  The Zr film has excellent practical characteristics even when used alone, but the phenol resin film does not have sufficient practical performance because only a certain effect is recognized even when used alone. However, when the Zr compound and the phenol resin are combined, a further excellent practical performance is exhibited.

The role of the Zr compound is to ensure corrosion resistance and adhesion. Zr compounds are thought to be Zr hydrated oxides and Zr phosphorous oxides composed of Zr oxide and Zr hydroxide, 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, but when the amount of Zr film exceeds 100 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 Zr film adhesion amount is preferably 1 to 100 mg / m ² in terms of metal Zr amount.

Moreover, although the corrosion resistance and adhesiveness which were excellent when Zr phosphorus oxide increased are exhibited, it is 0.1 mg / m < ² > or more by P amount that can recognize the effect clearly. Furthermore, when the amount of phosphoric acid film increases, the effect of improving corrosion resistance and adhesion also increases. However, if the amount of phosphoric acid film exceeds 50 mg / m ² in terms of P amount, the phosphoric acid film becomes too thick and the adhesion of the phosphoric acid film itself is increased. As a result, the electrical resistance increases and the weldability deteriorates. Therefore, the phosphoric acid film adhesion amount is preferably 0.1 to 50 mg / m ² in terms of P amount.

The role of the phenolic resin 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 50 mg / m ² in terms of the C amount, the electrical resistance increases and the weldability deteriorates. Therefore, the phenol resin film adhesion amount is preferably 0.1 to 50 mg / m ² in terms of C amount.

Since F is contained in the solution, it is taken into the film together with the Zr compound. F in the film does not affect the normal adhesion (primary adhesion) of paints and films, but it does not affect adhesion (secondary adhesion), rust resistance or coating during high temperature sterilization treatment such as retort treatment. It causes deterioration of subfilm corrosion. It is considered that this is because F in the film is eluted into water vapor or a corrosive liquid, and the bond with the organic film is decomposed or the base steel sheet is corroded. When the amount of F in the film exceeds 0.1 mg / m ² , the deterioration of these characteristics starts to become obvious, so the amount of F is preferably 0.1 mg / m ² or less. In order to reduce the F amount to 0.1 mg / m ² or less, after forming the Zr compound film, it may be washed by immersion treatment or spray treatment in warm water. The F amount can be reduced by increasing the length. Therefore, in order to reduce the F content in the film to 0.1 mg / m ² or less, it is only necessary to perform immersion treatment or spray treatment for 0.5 seconds or more with warm water of 40 ° C. or more. If the water temperature is lower than 40 ° C. or the processing time is lower than 0.5 seconds, the F amount in the film cannot be reduced to 0.1 mg / m ² or less, and the above-described various characteristics cannot be exhibited.

  The amount of metal Zr, the amount of P, and the amount of F contained in the Zr compound film according to the present invention can be measured by a quantitative analysis method such as fluorescent X-ray analysis. On the other hand, the amount of C contained in the phenol resin film can be measured by subtracting the amount of C existing in the steel sheet using TOC (total organic carbon meter).

  Further, the concentration of ammonium ions in the treatment solution for the cathodic electrolysis treatment may be adjusted as appropriate depending on the production equipment and production rate (capacity) within the range of about 100 to 10000 ppm and the concentration of nitrate ions of about 1000 to 20000 ppm. .

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

<Surface treatment layer on steel plate>
A surface treatment layer was applied on a steel plate having a thickness of 0.17 to 0.23 mm by using the following treatment methods (0) to (6).
(Treatment method 0) After cold rolling, a steel sheet was prepared by degreasing and pickling the annealed and pressure-adjusted original sheet.
(Treatment method 1) After cold rolling, the annealed and pressure-regulated original sheet was degreased and pickled, and then Sn was plated using a ferrostan bath to prepare an Sn-plated steel sheet.
(Treatment method 2) After cold rolling, the annealed and regulated original sheet was degreased and pickled, and then Ni-plated using a Watt bath to prepare a Ni-plated steel sheet.
(Treatment method 3) After cold rolling, Ni plating was performed using a Watt bath, a Ni diffusion layer was formed during annealing, and a Ni plated steel sheet was produced.
(Treatment method 4) After cold rolling, the annealed and pressure-regulated original sheet is degreased, pickled, plated with Sn using a ferrostan bath, and then subjected to reflow treatment to obtain an Sn-plated steel sheet having an Sn alloy layer Produced.
(Treatment method 5) After cold rolling, the annealed and pressure-regulated original sheet is degreased, pickled, and then subjected to Fe-Ni alloy plating using a sulfuric acid-hydrochloric acid bath, followed by Sn plating using a ferrostan bath. , Ni and Sn plated steel sheets were prepared.
(Treatment method 6) After cold rolling, the annealed and regulated original sheet was degreased, pickled, and then subjected to Sn-Ni alloy plating using a sulfuric acid-hydrochloric acid bath to prepare Ni and Sn plated steel sheets.

<Film formation>
After providing the surface treatment layer by the above treatment, a Zr compound film or a Zr compound-phenol resin film was formed by the following treatment methods (7) to (12).
(Treatment method 7) The steel sheet was immersed in a treatment solution in which 1000 ppm of fluoride Zr and 1000 ppm of ammonium nitrate were dissolved, and was subjected to cathodic electrolysis to form a Zr compound film.
(Treatment Method 8) The steel sheet was immersed in a treatment solution in which 1500 ppm of Zr fluoride, 500 ppm of phosphoric acid, and 5000 ppm of ammonium nitrate were dissolved, and was subjected to cathodic electrolysis to form a Zr compound film.
(Treatment method 9) The steel sheet was immersed in a treatment solution in which 4000 ppm of Zr fluoride, 300 ppm of phosphoric acid, 700 ppm of phenol resin, and 10,000 ppm of ammonium nitrate were dissolved, and cathode electrolysis was performed to form a Zr compound-phenol resin film.
(Treatment method 10) The steel sheet was immersed in a treatment solution in which 8000 ppm of Zr fluoride and 1000 ppm of ammonium nitrate were dissolved to form a Zr compound film.
(Treatment method 11) The steel sheet was immersed in a treatment solution in which fluorinated Zr 2000 ppm, phosphoric acid 500 ppm, and ammonium nitrate 10000 ppm were dissolved, and a Zr compound film was formed by cathodic electrolysis.
(Treatment method 12) The steel sheet was immersed in a treatment solution in which 1500 ppm of fluoride Zr, 1500 ppm of phosphoric acid, 500 ppm of phenol resin, and 5000 ppm of ammonium nitrate were dissolved, and a Zr compound-phenol resin film was applied by cathodic electrolysis.

<Washing treatment>
After the Zr compound film was formed by the above treatment, a water washing treatment was performed by the following treatment methods (13) to (14) to control the amount of F in the film.
(Treatment method 13) It was immersed in warm water of 40 ° C or higher.
(Treatment method 14) It was immersed in water at room temperature of about 15 ° C.

  In this example, the amount of metallic Ni and the amount of metallic Sn in the surface treatment layer were measured by a fluorescent X-ray method and specified using a calibration curve. Further, the amount of metal Zr, the amount of P, and the amount of F contained in the Zr compound film were measured by a quantitative analysis method such as fluorescent X-ray analysis. Further, the amount of C contained in the phenol resin film was measured by subtracting the amount of C existing in the steel sheet using TOC (total organic carbon meter).

<Performance evaluation>
About the test material which performed said process, performance evaluation was performed about each item of (A)-(F) shown below.

Then, performance evaluation was performed about each item of (A)-(G) 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: 0-2%, Δ: peeled area ratio: 2-10% :, x: peeled area ratio: 10 More than%).
(D) Primary paint adhesion After applying epoxy-phenol resin to the test material and baking it at 200 ° C for 30 minutes, put a grid with a depth reaching the ground iron at intervals of 1 mm, peel off with tape, Observed, peeled area ratio, 4 stages (◎: peeled area ratio: 0%, ○: peeled area ratio 0-5%, Δ: peeled area ratio: 5-30%: x: peeled area ratio: 30% Super).
(E) Adhesion of secondary paint An epoxy-phenol resin was applied to the test material, baked at 200 ° C. for 30 minutes, and then a grid having a depth reaching the ground iron at intervals of 1 mm, and then 125 ° C. for 30 minutes. After performing retort treatment, drying, the coating film is peeled off with a tape, and the peeling situation is observed. From the peeled area rate, 4 steps (◎: peeled area rate: 0%, ○: peeled area rate 0-5%, Δ : Peeling area ratio: 5 to 30%: x: peeling area ratio: more than 30%).
(F) Under-coating corrosion resistance After applying an epoxy-phenol resin to the test material and baking at 200 ° C. for 30 minutes, a cross-cut with a depth reaching the ground iron is added, 1.5% citric acid—1.5% Immerse in a test solution consisting of a salt mixture at 45 ° C for 72 hours, wash, dry, and then peel off the tape. From the evaluation of both the width of the steel plate and the corrosion area ratio of the flat plate portion, four stages (◎: Under-coating corrosion width less than 0.2 mm and flat plate portion corrosion area ratio 0%, ○: Under-coating corrosion width 0.2-0 Less than 3 mm and the corrosion area ratio of the flat plate part is more than 0% to 1%, Δ: Corrosion width under the coating film is less than 0.3 to 0.45 mm and the corrosion area ratio of the flat plate part is more than 1% to 5%, x: coating film The lower corrosion width exceeds 0.45 mm or the corrosion area ratio of the flat plate portion exceeds 5%.
(G) Retort rust resistance Retort treatment of the test material at 125 ° C. for 30 minutes, observation of rust generation, 4 stages from rust generation area rate (◎: rust generation area rate 0%, ○: rust generation area rate More than 0% to 1%, Δ: rust generation area ratio over 1% to 5%, x: rust generation area ratio over 5%).

  Examples 1 to 17 belonging to the scope of the present invention are all excellent in workability, weldability, film adhesion, primary paint adhesion, secondary paint adhesion, undercoat corrosion resistance, and rust resistance. It was. On the other hand, Comparative Examples 1 to 5 that do not satisfy any of the requirements of the present invention are workability, weldability, film adhesion, primary paint adhesion, secondary paint adhesion, undercoat corrosion resistance, and rust resistance. It has been found that at least some properties are inferior.

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 (5)

In a solution containing Zr ions, F ions, ammonium ions, nitrate ions, having a Zr compound film formed on the steel sheet by dipping or electrolytic treatment,
A steel plate for containers, wherein the amount of Zr compound film deposited is 1 to 100 mg / m ^{2 in} terms of metal Zr and 0.1 mg / m ² or less in terms of F. The solution further contains phosphate ions,
The steel sheet for containers according to claim 1, wherein the adhesion amount of the Zr compound film is further 0.1 to 50 mg / m ² in terms of P amount. The solution further contains a phenolic resin,
The Zr compound film further has a phenol resin film,
The steel plate for containers according to claim 2, wherein the adhesion amount of the phenol resin film is 0.1 to 50 mg / m ² in terms of C amount. The said steel plate is a surface treatment steel plate which has a surface treatment layer containing 10 to 1000 mg / m < ² > of Ni or 100 to 15000 mg / m < ² > of Sn at least on one side. The container steel plate according to claim 1. In the solution according to any one of claims 1 to 3 , after forming the Zr compound film, performing a cleaning process by immersion process or spray process for 0.5 seconds or more with warm water of 40 ° C or higher. A method for producing a steel plate for containers.