JP2008184630A - Surface treated metallic plate and method of manufacturing the same, resin coated metallic plate, metallic can and can cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treated metallic plate which is excellent in resin adhesive property without using Cr, not remarkably dangerous to human body, and can be replaced by a metallic plate for a Cr treated can, and a metod of manufacturing the same, a resin coated metallic plate formed by coating the surface treated metallic plate with an organic resin, a metallic can and can cap using the same. <P>SOLUTION: The surface treated metallic plate has a coating film containing Zr and O formed on at least one surface of a metallic plate, wherein fluorine content in the coating film is <0.1 mg/m<SP>2</SP>per one surface. The surface treated metallic plate is manufactured by applying cathodic electrolytic treatment or dipping treatment using an aqueous solution containing Zr and ≤0.03 mol/l F on at least one surface of the metallic plate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a metal plate mainly processed into a container such as a can, particularly a surface treatment that is excellent in adhesion to a resin such as a plastic film (hereinafter referred to as resin adhesion) and extremely harmless to the human body. The present invention relates to a metal plate, a manufacturing method thereof, a resin-coated metal plate in which an organic resin is coated on the surface-treated metal plate, a metal can using the same, and a can lid.

  For various metal cans such as beverage cans, food cans, pail cans and 18 liter cans, metal plates for Cr-treated cans such as chromated Sn-plated steel plates and electrolytic Cr-acid treated steel plates called tin-free steel plates are used. ing.

  In recent years, with the increasing awareness of the environment, the use of hexavalent Cr has been regulated worldwide, and alternative materials are also required for the above metal plates that use hexavalent Cr for production. As an alternative to these metal plates that do not use Cr, for example, Patent Document 1 discloses a plated steel sheet for cans having a film containing Mo or W, a phosphate, and a silanol group-containing compound. 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 treatment method for a metal material in which a surface treatment composition comprising a phosphoric acid compound, a fluoro acid, and a silane coupling agent is applied.

  On the other hand, various types of metal cans have been manufactured by processing metal cans such as tin-free steel sheets and then processing them into cans. Instead of this, a method of processing a laminated metal plate (resin-coated metal plate) obtained by laminating a resin such as a plastic film into a can body is frequently used. This laminated metal plate requires that the resin and the metal plate are in close contact with each other. In particular, a laminated metal plate used as a beverage can or a food can may undergo a retort sterilization process after filling the contents. For this reason, strong resin adhesion that does not cause the resin to peel even in a high-temperature and humid environment is required.

Moreover, when the corrosiveness of the contents is relatively weak, various metal plates for cans may be used without being coated or laminated after being plated with Sn or the like. For example, this uncoated and uncoated metal plate may be used for a can filled with food such as powdered milk. In such a metal plate, it is necessary that a substance harmful to the human body is not eluted from the surface treatment film, or a part of the surface treatment film containing the substance harmful to the human body does not fall off.
JP 2006-291288 A Japanese Patent Laid-Open No. 2001-220685 JP 2002-355921 A JP 2006-213958 A

  However, Mo or W described in Patent Document 1, phosphate, plated steel sheet for cans having a film containing a silanol group-containing compound, surface treatment for containers in which a phosphate layer is formed on the surface described in Patent Document 2 A laminated steel plate using a steel plate and a steel plate for containers on which a resin film having a phenol structure described in Patent Document 3 is insufficient in resin adhesion in a retort atmosphere. Further, in the metal material by the surface treatment method for applying the surface treatment composition comprising the phosphoric acid compound, the fluoro acid and the silane coupling agent described in Patent Document 4, it is one of the essential elements for the human body from the film. Since there is a risk of elution of F, which is harmful if overdose, it cannot be applied to beverage cans and food cans without painting or coating.

  The present invention relates to a surface-treated metal plate that can be used as a substitute for a metal plate for Cr-treated cans, has excellent resin adhesion, is extremely harmless to the human body, and a method for producing the same. An object of the present invention is to provide a resin-coated metal plate coated with a resin, a metal can using the same, and a can lid.

As a result of intensive research on surface-treated metal plates that can be used as substitutes for metal plates for Cr treatment cans, which do not use Cr, have excellent resin adhesion, and are extremely harmless to the human body, By forming a film containing Zr and O on the surface and making the F amount of this film less than 0.1 mg / m ² , it is a surface-treated metal that has excellent resin adhesion, has no danger of F elution, and is extremely harmless to the human body It was found that a plate was obtained.

The present invention has been made based on such findings, and has a coating containing Zr and O on at least one side of a metal plate, and the F amount of the coating is less than 0.1 mg / m ² per side. A surface-treated metal sheet is provided.

In the surface-treated metal plate of the present invention, the Zr content of the coating containing Zr and O is preferably ³ to 200 mg / m ² per side. Moreover, as a metal plate of a raw material, an electric Sn plating steel plate is suitable.

  The present invention also provides a resin-coated metal plate in which an organic resin is coated on the coating containing Zr and O of the surface-treated metal plate of the present invention, a metal can and a can lid using the same.

  The surface-treated metal plate of the present invention can be produced, for example, by subjecting at least one surface of the metal plate to cathodic electrolysis treatment or immersion treatment using an aqueous solution containing Zr and having an F amount of less than 0.03 mo1 / l. .

  The present invention makes it possible to produce a surface-treated metal plate that does not use Cr, has excellent resin adhesion, and is extremely harmless to the human body. The surface-treated metal plate of the present invention has no problem as an alternative to the conventional metal plate for Cr-treated cans, and is coated with an organic resin to form a resin-coated metal plate. Can be processed without any occurrence. In addition, since the surface-treated metal plate of the present invention does not cause elution of F, which is harmful to the human body when excessively consumed, it can be applied to beverage cans and food cans without coating or coating.

1) Surface-treated metal plate In the surface-treated metal plate of the present invention, a film containing Zr and O is formed on the surface of the metal plate, but by using a Zr-based film, the resin adhesion of the metal plate is improved, In addition, by setting the F amount of the film to less than 0.1 mg / m ² per side, F is not eluted even if it is used uncoated or uncoated, and it is not harmful to the human body.

  As the metal plate, a general steel plate for cans, an Al plate, an Al alloy plate, or the like can be used. In particular, it is preferable to use an electric Sn-plated steel sheet in order to ensure corrosion resistance.

If the Zr content of the coating containing Zr and O formed on the surface of the metal plate is less than 3 mg / m ² per side, the effect of improving the resin adhesion is insufficient, and if it exceeds 200 mg / m ² , the resin becomes more resinous. Since improvement in adhesion cannot be expected and the cost may increase, it is preferably ³ to 200 mg / m ² .

As a method for forming a film containing Zr and O, a method of subjecting a metal plate to cathodic electrolysis treatment or immersion treatment using an aqueous solution containing Zr and having an F content of less than 0.03 mo1 / l is suitable. By using an aqueous solution containing Zr and having an F content of less than 0.03 mo1 / l, the F content of the coating can be made less than 0.1 mg / m ² . The amount of Zr in the film can be adjusted by changing the current density and electrolysis time in the method of cathodic electrolysis treatment and by changing the immersion time in the immersion treatment. The amount of Zr in the film can be measured by surface analysis using fluorescent X-rays. The amount of O in the film can be confirmed by surface analysis by XPS. The F amount of the film can be calculated based on the Zr amount measured by the X-ray fluorescence analysis described above by measuring the element ratio of Zr and F on the film surface by XPS.

  As the aqueous solution containing Zr, an aqueous solution containing a zirconium compound such as zirconyl acetate, zirconyl nitrate, zirconium chloride or the like can be used. In particular, the method of cathodic electrolysis of a metal plate in an aqueous solution containing zirconyl acetate is preferable because it can form a uniform film efficiently.

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

  There is no limitation in particular as organic resin coat | covered on the surface treatment metal plate of this invention, Various thermoplastic resins and thermosetting resins can be mentioned. 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 metal 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 formation of the organic resin coating layer on the surface-treated metal plate can be performed 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. it can. 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 metal plate and thermally bonding it. That is, after melt-kneading the organic resin with an extruder, it is extruded from the T-die into a thin film, and the extruded molten resin film is passed through a pair of laminating rolls with a surface-treated metal plate to be pressed and integrated under cooling, Then quench rapidly. When extrusion coating a multilayer organic resin coating layer, an extruder for the surface layer resin and an extruder for the lower layer resin are used, and the resin flow from each extruder is merged in a multi-layer die, and thereafter Extrusion coating may be performed as in the case of the layer resin. Moreover, an organic resin coating layer can be formed on both surfaces of the surface-treated metal plate by passing a surface-treated metal plate vertically between a pair of laminate rolls and supplying a molten resin web to both sides thereof.

3) Metal can and can lid As long as the metal can of the present invention is formed from the above-mentioned resin-coated metal plate, any can-making method may be used. The metal 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 drawn and redrawn, bent and stretched by drawing and redrawing (stretching), and stretched and drawn by drawing and redrawing so that the organic resin coating surface of the surface-treated metal plate is on the inside of the can. -It is manufactured by attaching to a conventionally known means such as ironing or drawing / ironing.

  The can lid of the present invention may be formed by any conventionally known lid-making method as long as it is formed from the above-described resin-coated metal plate. 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 the embodiment of the present invention, and various modifications can be made within the scope of the claims.

As a metal plate,
A: Low carbon cold-rolled steel sheet with a thickness of 0.20mm and tempering grade T-4
B: Electric Sn-plated steel sheet with a thickness of 0.22mm and Sn coverage of 2.8g / m ² (single side)
C: 0.28mm thick Al plate (JIS5021H18)
After performing alkaline degreasing and pickling (however, pickling is omitted for the metal plate B), in the treatment liquid having the composition shown in Table 1, and cathodic electrolytic treatment or immersion under the same conditions as shown in Table 1. The surface treatment metal plate No. 1-6 was produced by processing, washing with water, and forming the film containing Zr and O on both surfaces of the metal plate. Here, in the cathode electrolysis treatment, Ti coated with Pt on the anode was used.

For comparison, the metal plate was subjected to electrolytic treatment under the conditions shown in Table 2, except for some metal plates (No. 7), and then immersed in an immersion treatment liquid having the composition shown in Table 2 for 1 second. Surface-treated metal plates No. 7 to 9 were produced. Here, the surface-treated metal plate No. In No. 7, a film containing an organic compound containing W, phosphate, and silanol groups by cathodic electrolysis was formed on the surface-treated metal 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. Surface-treated metal plate No. In No. 9, after the Sn film is formed by cathodic electrolysis, a Ti-containing phenol resin film is formed by dipping. Surface-treated metal plate No. In No. 10, a silane coupling agent treatment layer (adhesion amount: 0.5 g / m ² ) is formed by coating treatment.

  Surface treated metal plate No. 1-6 Zr amount, No. 7 W, P, Si amount, No. 8 Mg amount, No. 9 Sn, Ti amount, No. The Zr and Si amounts of the 10 coatings were measured by fluorescent X-ray analysis by comparison with a calibration plate obtained by wet analysis of the adhesion amount in advance. The presence of O in the films No. 1 to 6 was confirmed by XPS surface analysis. The F amounts of the films Nos. 1 to 6 and 10 were calculated based on the Zr amounts measured by the above X-ray fluorescence analysis by measuring the element ratio of Zr and F on the film surface by XPS. Tables 1 and 2 show the Zr content, F content, W content, P content, Si content, Mg content, Sn content, and Ti content of the coating.

Laminated metal plates (resin coating) were laminated on both surfaces of these surface-treated metal plates No. 1 to 10 with an isophthalic acid copolymerized polyethylene terephthalate film (organic resin coating layer) having a thickness of 25 μm and a copolymerization ratio of 12 mol%. Metal plates) No. 1 to 10 were prepared. Lamination was performed by sandwiching a metal plate heated to 210 ° C. and a film between a pair of rubber rolls, fusing the film to the metal plate, and cooling with water within 1 sec after passing through the rubber roll. At this time, the feed speed of the metal 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 conveyance direction of the portion where the rubber roll and the metal plate are in contact. And about the produced laminated metal plate 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 × 100 mm) obtained by cutting off a part 3 of the metal plate 1 while leaving the film 2 as shown in FIG. As shown in b), this 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.
◎: Peel length is less than 15mm ○: Peel length is 15mm or more and less than 20mm △: Peel length is 20mm or more and less than 50mm ×: Peel length is 50mm or more Also, the surface-treated metal plate No. before the organic resin coating layer is laminated About 1-10, the F elution amount was measured with the following method.
F elution amount: Four test pieces of 50 × 50 mm were immersed in 100 ml of 1 mass% citric acid aqueous solution, sealed and allowed to stand at 55 ° C. for 72 hours, and then the F amount in the solution was measured by ICP. If the amount of F eluted was less than 0.01 mg, there was no problem (O), and if it was 0.01 mg or more, there was a possibility of a problem (x).

  Table 3 shows the evaluation results of resin adhesion and F elution amount. In the laminated metal plates No. 1 to 6, which are examples of the present invention, all show good resin adhesion. On the other hand, laminated metal plates No. 7 to 9, which are comparative examples, are inferior in resin adhesion. Moreover, since these metal plates No. 1 to 9 before being laminated do not contain F in the film, there is no problem even if they are used without being laminated. On the other hand, the laminated metal plate No. 10 shows relatively good resin adhesion, but the metal plate before lamination has a large amount of F elution, which causes a problem when used without lamination. there is a possibility.

  Using the laminated metal plates No. 1 to 4, 7, and 9 produced in Example 1, the can is processed under the conditions shown in Table 4, and the opening end of the can body is necked in and flanged to make a metal seamless can No. 1-6 were produced. In addition, using the same laminated metal 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 metal cans Nos. 1 to 6 and the lids were visually inspected for abnormalities such as peeling of the film after the can making and perforation. After filling a metal can with a coffee drink at 50 ° C, double-wrap the lid, perform a retort treatment at 125 ° C for 25 min, leave it at 37 ° C for 6 months, and then open the can. Corrosion and film abnormalities were examined visually.

  The results are shown in Table 5. For metal cans Nos. 1 to 4 using the laminated metal plate according to the present invention, metal cans and 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 metal cans Nos. 5 and 6 using a laminated metal plate that is not the present invention, film abnormality after making the can and film abnormality (peeling) and corrosion after filling the contents were confirmed.

It is a figure explaining a 180 degree peel test.

Explanation of symbols

1 Metal plate
2 film
3 Parts cut out of a metal plate
4 weights
5 Peel length

Claims (7)

A surface-treated metal sheet having a film containing Zr and O on at least one side of the metal sheet, wherein the F amount of the film is less than 0.1 mg / m ² per side. ^2. The surface-treated metal sheet according to claim 1, wherein the Zr content of the coating containing Zr and O is 3 to 200 mg / m ² per side.   3. The surface-treated metal plate according to claim 1, wherein the metal plate is an electric Sn plated steel plate.   4. A resin-coated metal plate, wherein an organic resin is coated on the coating containing Zr and O of the surface-treated metal plate according to claim 1.   5. A metal can comprising the resin-coated metal plate according to claim 4.   5. A can lid comprising the resin-coated metal plate according to claim 4.   A method for producing a surface-treated metal plate, characterized in that at least one side of the metal plate is subjected to cathodic electrolysis treatment or immersion treatment using an aqueous solution containing Zr and having an F amount of less than 0.03 mo1 / l.

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