JP5300119B2 - Surface-treated steel sheets for seamless cans, resin-coated steel sheets, and seamless cans - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated steel sheet which is superior in adhesiveness to a resin and corrosion resistance though using no chromium and can be used as an alternative material to a tin-free steel sheet, a resin-coated steel sheet which is the surface-treated steel sheet coated with an organic resin, and a can and a can lid using the same. <P>SOLUTION: The surface-treated steel sheet has an Fe-Ni alloy layer on at least one surface of the steel sheet and has a coating film containing Ti and O on the Fe-Ni alloy layer. The coating film containing Ti and O formed on the surface-treated steel sheet preferably contains Ti in an amount of 3 to 200 mg/m<SP>2</SP>per single surface, and the Fe-Ni alloy layer preferably contains Ni in an amount of 5 to 1,000 mg/m<SP>2</SP>per single surface. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention is a steel sheet mainly processed into a container such as a can, and in particular, a surface-treated steel sheet excellent in adhesion with an organic resin such as a plastic film (hereinafter referred to as resin adhesion) and corrosion resistance, and the surface treatment. The present invention relates to a resin-coated steel sheet in which an organic resin is coated on a steel sheet, a can using the same, and a can lid.

  For various metal cans such as beverage cans, food cans, pail cans and 18 liter cans, electrolytic chromic acid treated steel plates such as tin-plated steel plates and tin-free steel plates are used. Among these, tin-free steel sheets are produced by electrolytic treatment of steel sheets in a plating bath containing hexavalent chromium, and are characterized by having excellent adhesion to resins such as paints.

  In recent years, due to the growing awareness of the environment, there is an increasing trend in the industry to regulate the use of toxic hexavalent chromium, and even for tin-free steel plates manufactured using a hexavalent chromium plating bath. Alternative materials are needed. For example, Patent Document 1 discloses a steel plate for containers that has been subjected to electrolytic treatment in a tungstic acid solution. Patent Document 2 discloses a surface-treated steel sheet for containers having a phosphate layer formed on the surface. Furthermore, Patent Document 3 has a phenol structure containing one or more of tannic acid or acetic acid and one or more of Ti or Zr or a compound thereof on a surface treatment layer containing one or more of Sn and Ni. A steel plate for containers in which a resin film is formed has been proposed. Furthermore, Patent Document 4 proposes a surface-treated metal material that does not contain phosphate ions and has an inorganic surface treatment layer and an organic surface treatment layer mainly composed of Ti, O, and F.

On the other hand, various metal cans were conventionally manufactured by coating tin plates such as tin-free steel plates and then processing them into cans. Instead, a method of processing a laminated steel plate (resin-coated steel plate) laminated with a resin such as a plastic film into a can body is frequently used. In this laminated steel plate, it is necessary that the resin and the steel plate are strongly adhered, and particularly in the laminated steel plate used as a beverage can or food can, a retort sterilization process may be performed after filling the contents, Strong resin adhesion is required so that the resin does not peel even in a high temperature and humid environment. In addition, the laminated steel sheet needs to have corrosion resistance so that even if the resin film is partially lost due to scratching or the like, the contents of the can are not eroded and a hole is not formed.
JP 2004-285380 A Japanese Patent Laid-Open No. 2001-220685 JP 2002-355921 A JP 2006-009046 A

  However, a laminated steel sheet using a container steel sheet subjected to electrolytic treatment in the tungstic acid solution described in Patent Document 1 and a container surface-treated steel sheet in which a phosphate layer is formed on the surface described in Patent Document 2, Both of the steel sheets for containers on which the resin film having a phenol structure described in Patent Document 3 is formed have insufficient resin adhesion in a retort atmosphere. Moreover, in the surface-treated metal material in which the inorganic surface treatment layer mainly composed of Ti, O, and F described in Patent Document 4 and the organic surface treatment layer are formed, the corrosion resistance when the resin film is missing is insufficient. is there.

  The present invention is a surface-treated steel sheet that does not use chromium, has excellent resin adhesion and corrosion resistance, and can be used as a substitute for a tin-free steel sheet, a resin-coated steel sheet in which an organic resin is coated on the surface-treated steel sheet, a can using the same, and The object is to provide a can lid.

  As a result of intensive research on surface-treated steel sheets that do not use chromium, have excellent resin adhesion and corrosion resistance, and can be used as substitutes for tin-free steel sheets, Fe-Ni alloy layers in order, It has been found that extremely excellent resin adhesion and corrosion resistance can be achieved by forming a film containing Ti and O.

  The present invention has been made based on such knowledge, and has a Fe—Ni alloy layer on at least one surface of a steel sheet, and a coating containing Ti and O on the Fe—Ni alloy layer. A surface-treated steel sheet is provided.

In the surface-treated steel sheet of the present invention, the Ti content of the coating containing Ti and O is preferably ³ to 200 mg / m ² per side. Further, the Ni content of the Fe—Ni alloy layer is preferably 5 to 1000 mg / m ² per side.

  The present invention also provides a resin-coated steel sheet in which the surface-treated steel sheet of the present invention is coated with an organic resin, a can using the same, and a can lid.

  According to the present invention, it is possible to produce a surface-treated steel sheet that is excellent in resin adhesion and corrosion resistance without using chromium. The surface-treated steel sheet of the present invention has no problem as an alternative to conventional tin-free steel sheets, and is coated with an organic resin to form a resin-coated steel sheet. Even if it is processed into a can or can lid and exposed to a retort atmosphere, No peeling occurs. In addition, even in resin missing portions such as scratches, the dissolution of the base steel is remarkably small and the corrosion resistance is extremely excellent.

1) Surface-treated steel sheet In the surface-treated steel sheet of the present invention, a film containing Ti and O is formed after forming a Fe—Ni alloy layer on at least one surface of the steel sheet. Needless to say, the Fe—Ni alloy layer and the coating containing Ti and O do not contain chromium.

  As the material steel plate, a general steel plate for cans using low carbon steel, extremely low carbon steel, or the like can be used.

  The Fe—Ni alloy layer formed on the steel plate surface imparts corrosion resistance to the steel plate.

If the amount of Ni in the Fe-Ni alloy layer is less than 5 mg / m ² per side, the effect of improving corrosion resistance may not be fully obtained, and if it exceeds 1000 mg / m ² , further improvement in corrosion resistance cannot be expected, resulting in cost reduction. Since it becomes high, it is preferable that it is 5-1000 mg / m < ² >. Note that the amount of Ni in the Fe—Ni alloy layer can be measured by surface analysis using fluorescent X-rays.

  In addition, as a method for forming an Fe-Ni alloy layer, Ni is plated on a steel sheet by a known plating method using a watt bath or the like, and then Ni and Fe in the steel sheet are interdiffused by performing an appropriate heat treatment. Is appropriate. In this method, the Fe-Ni alloy layer is not formed on the outermost surface when the amount of heat is small, but the presence of Fe on the surface can be confirmed by surface analysis using XPS (photoelectron spectrometer). Heat treatment conditions for forming the alloy layer can be determined.

  By forming a film containing Ti and O on the Fe—Ni alloy layer, good resin adhesion can be obtained. The cause of this is not clear at present, but it is assumed that a strong intermolecular force is generated between the high molecular weight film mainly composed of Ti oxide and the resin.

If the amount of Ti in the coating containing Ti and O is less than 3 mg / m ² per side, the effect of improving resin adhesion may not be obtained sufficiently, and if it exceeds 200 mg / m ² , the resin adhesion will be further improved. However, it is preferable to be 3 to 200 mg / m ² . Note that the amount of Ti in the film can be measured by surface analysis using fluorescent X-rays. The amount of O is not particularly defined, but its presence can be confirmed by surface analysis using XPS.

  As a method of forming a film containing Ti and O, a method of cathodic electrolytic treatment or immersion treatment of a steel sheet on which an Fe-Ni alloy layer is formed in an aqueous solution containing fluorotitanate ions, or fluorotitanate ions and fluorine salts are used. A method of cathodic electrolytic treatment or immersion treatment of a steel sheet on which an Fe—Ni alloy layer has been formed in an aqueous solution containing it is suitable. As the compound that gives fluorotitanate ions, fluorinated titanate, ammonium fluoride titanate, potassium fluoride titanate, and the like can be used. As the fluorine salt, sodium fluoride, potassium fluoride, silver fluoride, tin fluoride, or the like can be used. In particular, the method of cathodic electrolysis of a steel sheet with an Fe-Ni alloy layer in an aqueous solution containing potassium fluorinated titanate or an aqueous solution containing potassium fluorinated titanate and sodium fluoride is efficient and homogeneous. It is possible and preferable to form a thin film. What is necessary is just to determine suitably the current density and electrolysis time in cathodic electrolysis processing, and the immersion time in immersion treatment according to required Ti amount.

2) Resin coated steel sheet (laminated steel sheet)
The surface-treated steel sheet of the present invention can be coated with an organic resin to form a resin-coated steel sheet. As described above, since the surface-treated steel sheet of the present invention is excellent in resin adhesion, this resin-coated steel sheet has excellent corrosion resistance and workability.

  The organic resin coated on the surface-treated steel sheet of the present invention is not particularly limited, and various thermoplastic resins and thermosetting resins can be exemplified. For example, polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic ester copolymer, olefin resin film such as ionomer, or polyester film such as polybutylene terephthalate, or nylon 6 It may be a non-stretched or biaxially stretched thermoplastic resin film such as a polyamide film such as nylon 6,6, nylon 11, or nylon 12, a polyvinyl chloride film, or a polyvinylidene chloride film. When using an adhesive during lamination, urethane adhesive, epoxy adhesive, acid-modified olefin resin adhesive, copolyamide adhesive, copolyester adhesive (thickness: 0.1 to 5.0 μm), etc. Is preferably used. Furthermore, a thermosetting paint may be applied to the surface-treated steel plate side or film side in a thickness range of 0.05 to 2 μm, and this may be used as an adhesive.

  Furthermore, modified epoxy paint such as phenol epoxy, amino-epoxy, vinyl chloride-vinyl acetate copolymer, saponified vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, epoxy-modified- , Epoxyamino-modified, Epoxyphenol-modified Vinyl paint or Modified vinyl paint, Acrylic paint, Synthetic rubber paint such as styrene-butadiene copolymer, etc. It may be a combination.

  In the present invention, the thickness of the organic resin coating layer is desirably 3 to 50 μm, particularly 5 to 40 μm. When the thickness is below the above range, the corrosion resistance becomes insufficient, and when the thickness is above the above range, problems are likely to occur in terms of workability.

  In the present invention, the organic resin coating layer can be formed on the surface-treated steel sheet by any means, for example, by an extrusion coating method, a cast film thermal bonding method, a biaxially stretched film thermal bonding method, or the like. . In the case of the extrusion coating method, it can be produced by extrusion coating an organic resin in a molten state on a surface-treated steel plate and thermally bonding it. That is, after melt-kneading the organic resin with an extruder, it is extruded from a T-die into a thin film, and the extruded molten resin film is passed through a pair of laminating rolls together with a surface-treated steel plate, and is pressed and integrated under cooling, Cool quickly. When extrusion coating a multi-layered organic resin coating layer, use multiple extruders for each layer, merge the resin flow from each extruder in a multi-layer die, and thereafter, as in the case of a single layer resin Extrusion coating may be performed. Moreover, an organic resin coating layer can be formed on both surfaces of the surface-treated steel sheet by passing the surface-treated steel sheet vertically between a pair of laminate rolls and supplying a molten resin web to both sides thereof.

3) Can and can lid As long as the can of the present invention is formed from the above-mentioned resin-coated steel sheet, any can manufacturing method may be used. The can can be a three-piece can having a side seam, but is generally preferably a seamless can (two-piece can). This seamless can is subjected to conventionally known means such as drawing / redrawing, bending / stretching by drawing / redrawing (stretching), bending / stretching / drawing by drawing / redrawing, or drawing / ironing. Manufactured.

  Moreover, the can lid of this invention may be based on the conventionally well-known arbitrary lid-making method, as long as it is formed from the resin-coated steel plate mentioned above. In general, the present invention can be applied to a stay-on-tab type easy open can lid and a full open type easy open can lid.

  The above description is merely an example of an embodiment of the present invention, and various modifications can be made within the scope of the claims.

As a steel plate
A: Low carbon cold-rolled steel sheet with a thickness of 0.20mm and tempering grade T-4
B: Using an ultra-low carbon cold-rolled steel sheet with a thickness of 0.20mm and a tempering grade T-2, after alkaline degreasing and pickling, Watts bath (composition: nickel sulfate 240g / L, nickel chloride 45g / L Cathodic electrolysis was carried out in cathodic electrolysis conditions 1 shown in Table 1 in boric acid 30 g / L), washed with water, and Ni-plated on the steel sheet. Thereafter, the steel sheet was subjected to heat treatment at 700 ° C. for 30 seconds in an atmosphere of 3 vol% hydrogen and 97 vol% nitrogen to diffuse Ni and Fe of the steel sheet to form a Fe—Ni alloy layer on the steel sheet. Subsequently, cathodic electrolysis or immersion treatment was performed in a 12 g / L aqueous solution of potassium titanate titanate under cathodic electrolysis conditions 2 shown in Table 1, and a film containing Ti and O was formed on both surfaces of the steel sheet. .1-6 were produced. In the cathodic electrolytic treatment, platinum coated Ti was used for the anode.

  For comparison, electrolytic treatment and 1-second immersion treatment (except for No. 7) were performed on the steel plate under the conditions shown in Table 2, and surface-treated steel plates No. 7 to 10 were produced. Here, in the surface-treated steel plate No. 7, the coating containing W by the cathodic electrolysis treatment was applied to the surface-treated steel plate No. 7. In No. 8, after the anodic electrolytic treatment, a magnesium-containing film is formed by immersing in an aqueous magnesium phosphate solution. In the surface-treated steel sheet No. 9, after the Sn film was formed by the cathodic electrolysis treatment, the Ti-containing phenol resin film was formed by the immersion treatment. In the surface-treated steel sheet No. 10, after the Zr film is formed by the cathodic electrolysis treatment, the silane coupling agent treatment layer is formed by the immersion treatment.

  Surface treatment steel plate No. 1-6 alloy layer Ni amount, coating Ti amount, No. 7 coating W amount, No. 8 coating Mg amount, No. 9 coating Sn, Ti amount, No The Zr and Si amounts of the film of .10 were measured by fluorescent X-ray analysis in comparison with a calibration plate obtained by wet analysis of the adhesion amount in advance. O was also confirmed by XPS surface analysis. Tables 1 and 2 show the Ni amount of the alloy layer, the Ti amount, W amount, Mg amount, Sn amount, Zr amount, and Si amount of the coating.

Laminated steel sheets (resin-coated steel sheets) No. are laminated on both surfaces of these surface-treated steel sheets No. 1 to 10 by laminating an isophthalic acid copolymerized polyethylene terephthalate film (organic resin) with a thickness of 25 μm and a copolymerization ratio of 12 mol%. 1 to 10 were produced. Lamination was performed by sandwiching a steel plate and a film heated to 210 ° C. between a pair of rubber rolls, fusing the film to the steel plate, and cooling with water within 1 sec after passing through the rubber roll. At this time, the feeding speed of the steel plate was 40 m / min, and the nip length of the rubber roll was 17 mm. Here, the nip length is the length in the transport direction of the portion where the rubber roll and the steel plate are in contact. And about the produced laminated steel plates No. 1-10, the following resin adhesiveness evaluation was performed.
Resin adhesion evaluation: Resin adhesion was evaluated by a 180 ° peel test in a retort atmosphere at a temperature of 130 ° C. and a relative humidity of 100%. The 180 ° peel test is a test piece (size: 30 mm x 100 mm) obtained by cutting a part 3 of the steel plate 1 while leaving the film 2 as shown in Fig. 1 (a). As shown, it is a film peeling test performed by attaching a weight 4 (100 g) to one end of the test piece, turning it 180 ° to the film 2 side, and allowing it to stand for 30 minutes. Then, the peel length 5 shown in FIG. 1 (c) was measured, and the resin adhesion was evaluated as follows, and if it was ま た は or ◯, the resin adhesion was good.
A: Peel length is less than 15 mm B: Peel length is 15 mm or more and less than 20 mm Δ: Peel length is 20 mm or more and less than 50 mm X: Peel length is 50 mm or more The results are shown in Table 3. In the laminated steel plates No. 1 to 6 which are examples of the present invention, all show good resin adhesion. On the other hand, the laminated steel plates No. 7 to 10, which are comparative examples, are inferior in resin adhesion.

The resin-coated surfaces of the laminated steel plates No. 1 to 10 produced in Example 1 were subjected to a cut that reached the steel plate substrate using a cutter knife, and the immersion test was performed with the test liquid compositions and conditions shown in Table 4. . And the corrosion resistance of a cut part was evaluated as follows, and if it was (circle), it was considered that corrosion resistance was favorable.
○: No corrosion Δ: Slightly corrosion ×: Large corrosion Table 5 shows the results. Laminated steel sheet No. 1 to 6 have good corrosion resistance. On the other hand, the laminated steel plate No. 7-10 are all inferior in corrosion resistance.

  Using the laminated steel plates No. 1 to 10 produced in Example 1, the cans were processed under the conditions shown in Table 6, and the opening end of the can body was necked in and flanged to produce seamless cans No. 1 to 10 Produced. Also, using the same laminated steel plate, a 209-diameter SOT lid was prepared, and the inner and outer surfaces of the score processed part were repaired with an epoxy phenol-based paint. The produced seamless cans Nos. 1 to 10 and the lids were visually inspected for abnormalities such as film peeling and perforation after canning. In addition, after filling the can with coffee drink at 50 ° C, double-wrap the lid, perform retort treatment at 125 ° C for 25 min, leave it at 37 ° C for 6 months, and then open the can to corrode the inner surface of the can And film abnormalities were visually inspected.

  The results are shown in Table 7. For seamless cans Nos. 1 to 6 using the laminated steel sheet according to the present invention, the cans and the lids were examined after making the cans and filling the contents, but no film abnormality was confirmed in any of them.

  On the other hand, in seamless cans Nos. 7 to 10 using a laminated steel sheet not according to the present invention, it was confirmed that there was a film abnormality after making the can, and a film abnormality (peeling) and corrosion after filling the contents.

It is a figure explaining a 180 degree peel test.

Explanation of symbols

1 Steel plate
2 film
3 Parts cut from steel plate
4 weights
5 Peel length

Claims (4)

On at least one surface of the steel sheet, plated with Ni, a Fe-Ni alloy layer Ni amount is formed by interdiffusion of the Fe in the Ni and the steel sheet is per one side 5 to 1000 mg / ^{m 2} by subsequently performing heat treatment A surface-treated steel sheet for seamless cans , comprising a coating containing Ti and O formed by cathodic electrolytic treatment or immersion treatment on the Fe-Ni alloy layer. The surface-treated steel sheet for seamless cans according to claim 1, wherein the amount of Ti of the coating containing Ti and O is 3 to 200 mg / m ² per side. A resin-coated steel sheet, wherein the surface-treated steel sheet for seamless cans according to claim 1 or 2 is coated with an organic resin. A seamless can comprising the resin-coated steel sheet according to claim 3.

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