JP5482775B2 - Surface-treated metal plate, resin-coated metal plate, metal can and can lid - Google Patents

Description

  The present invention is a metal plate mainly processed into a container such as a can, particularly a surface-treated metal plate excellent in adhesion to a resin such as a plastic film (hereinafter referred to as resin adhesion) and corrosion resistance, and a method for producing the same The present invention also relates to a resin-coated metal plate in which an organic resin is coated on the surface-treated metal plate, a metal can and a can lid using the same.

  Various metal cans such as beverage cans, food cans, pail cans and 18 liter cans use metal plates such as electrolytic chromic acid treated steel plates called tin-plated steel plates or tin-free steel plates. Among these, tin-free steel plates are manufactured by electrolytic treatment of steel plates in a bath containing hexavalent chromium, and are characterized by excellent resin adhesion to paints and the like.

  In recent years, with the increasing awareness of the environment, the use of hexavalent chromium has been restricted worldwide, and alternative materials are also required for tin-free steel sheets that use a hexavalent chromium bath for production. As an alternative to tin-free steel plates that do not use chromium, 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. Patent Document 3 discloses a resin film having 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 a container to be subjected to is proposed. Patent Document 4 proposes a surface-treated metal material in which an inorganic surface treatment layer containing Ti, O, and F as a main component and an organic surface treatment layer, which does not contain phosphate ions, is formed.

  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. In addition, the metal plate used for the laminated metal plate must have excellent corrosion resistance that does not cause puncture due to contents or the like even when the resin is partially lost due to scratches or the like.

JP 2004-285380 A Japanese Patent Laid-Open No. 2001-220685 JP 2002-355921 A JP 2006-009046 A

  However, a steel plate for containers subjected to electrolytic treatment in the tungstic acid solution described in Patent Document 1, a laminated steel plate using a surface-treated steel sheet for containers in which a phosphate layer is formed on the surface described in Patent Document 2, In both the steel sheet for containers to which the resin film having a phenol structure described in Patent Document 3 is applied, the resin adhesion in the retort sterilization process is insufficient. Further, the surface-treated metal material on which the inorganic surface treatment layer mainly composed of Ti, O, and F and the organic surface treatment layer described in Patent Document 4 have insufficient corrosion resistance at the resin defect portion.

  The present invention relates to a surface-treated metal plate that does not use chromium, has excellent resin adhesion and corrosion resistance, and can be used as a substitute for a tin-free steel plate, a method for producing the same, and a resin-coated metal obtained by coating the surface-treated metal plate with an organic resin An object is to provide a plate, a metal can using the plate, and a can lid.

  As a result of intensive research on a surface-treated metal plate that does not use chromium, is excellent in resin adhesion and corrosion resistance, and can be used as a substitute for a tin-free steel plate, a Ni film is formed on the surface of the metal plate. It has been found that by forming a film containing Ti and O on the film and further forming an organic film on the film, it is possible to achieve both excellent resin adhesion and corrosion resistance.

  The present invention has been made on the basis of such knowledge, and has a Ni film on at least one surface of a metal plate, a film containing Ti and O on the Ni film, and a film containing Ti and O There is provided a surface-treated metal plate having an organic film thereon, and the organic film is a film formed by drying after contact with an organic acid.

At this time, the organic acid is preferably a hydroxy acid. More preferably, the hydroxy acid comprises at least one acid selected from citric acid, tartaric acid, glycolic acid, lactic acid, glyceric acid, and mandelic acid. Furthermore, it is preferable that the amount of Ti of the film containing Ti and O is 3 to 200 mg / m ² .

  The present invention further provides a resin-coated metal plate in which an organic resin is coated on the organic film of the surface-treated metal plate as described above, a metal can and a can lid using the same.

  According to the present invention, it is possible to produce a surface-treated metal plate that is excellent in resin adhesion and corrosion resistance without using chromium. The surface-treated metal plate of the present invention has no problem as an alternative to the conventional tin-free steel plate, and is coated with an organic resin to form a resin-coated metal plate. Can be processed without happening. Further, even in a resin defect due to scratches or the like, the dissolution of the base metal is remarkably small and the corrosion resistance is extremely excellent.

It is a figure explaining a 180 degree peel test.

1) Surface-treated metal plate In the surface-treated metal plate of the present invention, after forming a Ni film on at least one side of the metal plate, forming a film containing Ti and O on the Ni film, and further forming an organic film on the film Is formed.

  As the metal plate, a general steel plate for cans, an aluminum plate, an aluminum alloy plate, or the like can be used.

The Ni coating formed on the surface of the metal plate is firmly bonded to the base metal plate and imparts corrosion resistance to the metal plate. At this time, if the amount of Ni coating on one side of the metal plate is less than 10 mg / m ² , the effect of improving corrosion resistance is insufficient, and if it exceeds 1000 mg / m ² , further improvement in corrosion resistance cannot be expected. Since it becomes high, it is preferable that it is 10-1000 mg / m < ² >. Note that the Ni content can be measured by fluorescent X-ray analysis.

  It is convenient and suitable to form the Ni film by a method of cathodic electrolysis using a known electroplating bath. As the electroplating bath, for example, a so-called Watt bath containing nickel sulfate, nickel chloride and boric acid can be used.

  When a film containing Ti and O is formed on the Ni film and then an organic film is formed on the film, the resin adhesion is improved.

  As a method for forming a film containing Ti and O, a method of cathodic electrolysis treatment or immersion treatment in a solution containing Ti is preferable. In particular, a method of cathodic electrolysis or immersion treatment of a metal plate in an aqueous solution containing fluorotitanate ions, or a method of cathodic electrolysis treatment or immersion treatment of a metal plate in an aqueous solution containing fluorotitanate ions and a fluorine salt is suitable. It is. 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 metal plate in an aqueous solution of potassium fluorinated titanate and further in an aqueous solution containing potassium fluorinated titanate and sodium fluoride can form a uniform film efficiently. It is preferable.

  The organic film formed on the film containing Ti and O is formed by contacting a metal plate on which an Ni film and a film containing Ti and O are sequentially formed with an organic solution and then drying the contacted metal plate. At this time, as organic substances, for example, alcohols, phenols, ethers, aldehydes, ketones, carboxylic acids, amines, and the like can be used. Among these, non-volatile substances that are solid at normal temperature are preferable, and organic acids, particularly hydroxy acids are preferable. Hydroxy acid is a general term for organic compounds having a carboxyl group and an alcoholic hydroxyl group in one molecule. In the present invention, hydroxy acid is selected from citric acid, tartaric acid, glycolic acid, lactic acid, glyceric acid, mandelic acid, and the like. It is preferable to use at least one acid.

If the adhesion amount of the organic film formed on the film containing Ti and O is less than 0.1 mg / m ² , the effect of improving resin adhesion is insufficient, and if it exceeds 50 mg / m ² , cohesive failure occurs in the film. In some cases, the adhesiveness of the resin may be lowered, so that the content is preferably 0.1 to 50 mg / m ² . The amount of organic substance or organic film deposited can be measured by dissolving the film with a suitable organic solvent and analyzing the composition of the gas generated by combustion by gas chromatography.

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 adhesion to the resin is insufficient, and if it exceeds 200 mg / m ² , further improvement in adhesion can be expected. However, since it becomes expensive, it is preferable that it is 3-200 mg / m < ² >. In addition, the measurement of the Ti amount of the film can be performed by fluorescent X-ray analysis. The amount of O is not particularly defined, but its presence can be confirmed by surface analysis using XPS.

2) Resin-coated metal plate (laminated metal plate)
The organic film of 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, 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 adhesives for lamination, urethane adhesives, epoxy adhesives, acid-modified olefin resin adhesives, copolyamide adhesives, copolyester adhesives (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, Thermoplastic or thermosetting paint such as synthetic rubber paint such as styrene-butadiene copolymer, or a combination of two or more 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 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 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 an 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: Ultra low carbon cold-rolled steel sheet with a thickness of 0.20mm and tempering grade T-2
C: A JIS5021H18 aluminum plate with a thickness of 0.28 mm was used, and after alkaline degreasing and pickling, the cathode was subjected to cathodic electrolysis (1) conditions shown in Table 1 in the treatment liquid having the composition shown in Table 1. Electrolytic treatment was performed, and the Ni film was formed on both surfaces of the metal plate by washing with water. Next, cathodic electrolysis treatment or immersion treatment was performed under the conditions of cathodic electrolysis treatment (2) shown in Table 1, and dried to form films containing Ti and O on both surfaces of the metal plate. Finally, it was immersed in an organic treatment liquid having the composition shown in Table 1, washed with water and dried to prepare surface-treated metal plates No. 1 to No. 6. In the cathode electrolysis treatment, iridium oxide-coated titanium was used for the anode.

  For comparison, electrolytic treatment was performed using the metal plate A under the conditions shown in Table 2, and a portion of the metal plate was then immersed in an immersion treatment liquid having the composition shown in Table 2 for 1 second to obtain a surface-treated metal. Plates No. 12 to 15 were produced. Here, in the surface-treated metal plate No. 12, a W-containing film is formed by cathodic electrolysis treatment, and in the surface-treated metal plate No. 13, an anodic electrolysis treatment is performed, followed by immersion treatment in a magnesium phosphate aqueous solution to form an Mg-containing film. Has been. In the surface-treated metal plate No. 14, 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 metal plate No. 15, after the Zr film was formed by the cathodic electrolysis treatment, the silane coupling agent treatment layer was formed by the immersion treatment.

  Surface treated metal plate No.1-6 film Ti amount, No.12 film W amount, No.13 film Mg amount, No.14 film Sn, Ti amount, No.15 film The Zr and Si amounts 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 was confirmed by XPS surface analysis. Moreover, the adhesion amount of the organic film of the surface-treated metal plates No. 1 to 6 was measured by dissolving the film in water or ethanol and analyzing the composition of the gas generated by combustion by gas chromatography. Tables 1 and 2 show the Ti amount, W amount, Mg amount, Sn amount, Zr amount, Si amount, and organic film adhesion amount (per one side) of the film.

  Laminated metal is laminated on both surfaces of these surface-treated metal plates No. 1-6 and 12-15 with an isophthalic acid copolymerized polyethylene terephthalate film (organic resin coating layer) with a thickness of 25 μm and a copolymerization ratio of 12 mol%. Plates (resin-coated metal plates) No. 1 to 6 and 12 to 15 were produced. Lamination was performed by sandwiching a metal plate heated to 245 ° C. and a film between a pair of rubber rolls, fusing the film to the metal plate, and cooling with water within 1 second 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. 1-6, 12-15, 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.
A: Peel length is less than 15 mm B: Peel length is 15 mm or more and less than 20 mm B: 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. Laminated metal plates Nos. 1 to 6 as examples of the present invention all exhibit extremely good resin adhesion. On the other hand, the laminated metal plates No. 12 to 15 as comparative examples are all inferior in resin adhesion.

Tests shown in Table 4 were performed by crossing two cut scratches reaching the metal plate substrate using a cutter on the resin-coated surfaces of the laminated metal plates No. 1, 3-6, 14, and 15 prepared in Example 1. It was immersed in a test solution under the conditions, and the corrosion resistance was investigated. And the corrosion resistance of the cut flaw part was evaluated as follows.
○: No corrosion Δ: Slight corrosion ×: Large corrosion Table 5 shows the results. Laminated metal plates No. 1 and 3 to 6 which are examples of the present invention show good corrosion resistance. On the other hand, the laminated metal plates No. 14 and 15 which are comparative examples are all inferior in corrosion resistance.

  Using the laminated metal plates No.1, 3-6, and 14 produced in Example 1, the can is made under the conditions shown in Table 6, 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 7. For metal cans Nos. 1 to 5 using the laminated metal plate according to the present invention, the metal can and the lid were examined after making the can and filling the contents, but in any case, no abnormality of the film could be confirmed.

  On the other hand, in metal can No. 6 using a laminated metal plate not according to the present invention, film abnormality after can making, film abnormality (peeling) and corrosion after filling contents were confirmed.

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

Claims (6)

At least one surface of the metal plate has a Ni film, has a film containing Ti and O on the Ni film, has an organic film on the film containing Ti and O, and the organic film is converted into a hydroxy acid . after contact, Ri coating der formed by drying,
The surface-treated metal plate, wherein the film containing Ti and O is a film formed by cathodic electrolytic treatment or immersion treatment . The surface-treated metal sheet according to claim 1 , wherein the hydroxy acid comprises at least one acid selected from citric acid, tartaric acid, glycolic acid, lactic acid, glyceric acid, and mandelic acid. Surface-treated metal sheet according to any one of claims 1 or 2, wherein the Ti content of the film containing Ti and O is 3-200 mg / m ^2. An organic resin is coated on an organic film of the surface-treated metal plate according to any one of claims 1 to 3 . A metal can comprising the resin-coated metal plate according to claim 4 . A can lid comprising the resin-coated metal plate according to claim 4 .

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