JP2013127124A - Method for manufacturing surface treated steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface treated steel sheet manufacturing method in which a surface treated steel sheet that is superior in wet resin adhesion and corrosion resistance and can be an alternative for a tin-free steel sheet is manufactured without using Cr.SOLUTION: The method is characterized in that, after a corrosion resistant film formed of one layer selected from layers of Ni, Sn, Fe-Ni alloy, Fe-Sn alloy, and Fe-Ni-Sn alloy is formed at least on one surface of the steel sheet, an adhesive film is formed by cathodically electrolyzing the steel sheet in an aqueous solution containing ions of Ti, and further containing ions of at least one metal selected from Co, Fe, Ni, V, Cu, Mn, and Zn, wherein Ti is 0.008 to 0.07 mol/l, and the content of at least one metal selected from Co, Fe, Ni, V, Cu, Mn, and Zn relative to Ti is 0.01 to 10 by mole ratio.

Description

  The present invention relates to a surface-treated steel sheet used mainly for containers such as cans after being coated with a resin film by laminating a resin film or the like on the surface or by applying a paint containing resin, particularly in a high-temperature and humid environment. The present invention relates to a method for producing a surface-treated steel sheet that has excellent adhesion to a resin coated in (hereinafter referred to as wet resin adhesion) and exhibits excellent corrosion resistance even when the coated resin is missing.

  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 sheets are manufactured by electrolytically treating steel sheets in a plating bath containing hexavalent Cr, and are characterized by excellent wet resin adhesion to resins such as paints.

  In recent years, due to the increasing awareness of the environment, the use of hexavalent Cr has been regulated worldwide, and there is an alternative material for tin-free steel plates manufactured using a hexavalent Cr plating bath. It has been demanded. 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 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 resin-coated metal plate coated with a resin such as a resin film into a can body is frequently used. In this resin-coated metal plate, it is necessary that the resin is strongly adhered to the metal plate. In particular, the resin-coated metal plate used as a beverage can or a food can is subjected to a retort sterilization process after filling the contents. In some cases, strong wet resin adhesion is required so that the resin does not peel even in a high temperature wet environment. Further, the resin-coated metal plate is required to have excellent corrosion resistance that does not cause piercing due to the contents of the can even when the resin is partially lost due to scratching or the like.
JP 2004-285380 A Japanese Patent Laid-Open No. 2001-220685 JP 2002-355921 A JP 2006-009046 A

  However, a resin-coated steel sheet using a container steel plate subjected to electrolytic treatment in a tungstic acid solution described in Patent Document 1, and a container surface-treated steel sheet having a phosphate layer formed on the surface described in Patent Document 2 The steel sheet for containers in which the resin film having a phenol structure described in Patent Document 3 is formed, and the inorganic surface treatment layer and the organic surface treatment layer mainly composed of Ti, O, and F described in Patent Document 4 are formed. In any of the surface-treated metal materials, the wet resin adhesion in the retort atmosphere is insufficient.

  An object of the present invention is to provide a method for producing a surface-treated steel sheet that does not use Cr, has excellent wet resin adhesion and corrosion resistance, and can be used as a substitute for a tin-free steel sheet.

  As a result of intensive research on surface-treated steel sheets that do not use Cr, have excellent wet resin adhesion and corrosion resistance, and can be used as substitutes for tin-free steel sheets, the surface of the steel sheet has a Ni layer, a Sn layer, and A corrosion-resistant film composed of an Fe alloy layer of these elements is formed, and an adhesive film containing Ti, and further containing elements such as Co, Fe, Ni, V, Cu, Mn, and Zn is formed on the corrosion-resistant film. By doing so, it was found that excellent wet resin adhesion and corrosion resistance can be achieved at the same time.

  The present invention has been made based on such knowledge, and at least one surface of a steel plate is selected from a Ni layer, a Sn layer, a Fe—Ni alloy layer, a Fe—Sn alloy layer, and a Fe—Ni—Sn alloy layer. After forming a corrosion-resistant film consisting of at least one layer, containing ions containing Ti, and further containing ions containing at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn Provided is a method for producing a surface-treated steel sheet, characterized in that an adhesive film is formed by cathodic electrolysis in an aqueous solution.

At this time, Ti is 0.008 to 0.07 mol / l (l: liter), and at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn has a molar ratio to Ti. It is preferable to use an aqueous solution containing 0.01 to 10. The adhesive film is preferably 3 to 200 mg / m ² per side as the amount of Ti.

  According to the present invention, it is possible to produce a surface-treated steel sheet excellent in wet resin adhesion and corrosion resistance without using Cr. The surface-treated steel sheet produced by the production method of the present invention can be used as a substitute for conventional tin-free steel sheets without any problem and without being coated with a resin on a container containing oil, organic solvent, paint, or the like. Further, even if the resin is coated to form a resin-coated steel sheet, processed into a can or can lid and exposed to a retort atmosphere, the resin does not peel at all. Further, even in a resin missing portion such as a scratch, the dissolution of Fe as a base material is remarkably small, and the corrosion resistance is extremely excellent.

It is a figure explaining a 180 degree peel test.

1) Manufacturing method of surface-treated steel sheet In the manufacturing method of the present invention, at least one surface of the steel sheet is selected from a Ni layer, a Sn layer, a Fe-Ni alloy layer, a Fe-Sn alloy layer, and a Fe-Ni-Sn alloy layer. After forming a corrosion-resistant film composed of at least one layer, the film contains Ti-containing ions on the corrosion-resistant film, and at least one selected from Co, Fe, Ni, V, Cu, Mn, and Zn. The adhesive coating is formed by cathodic electrolysis in an aqueous solution containing ions containing the above metals.

  As a raw steel plate, a general steel plate for cans can be used.

  The corrosion-resistant film formed on the steel sheet surface is firmly bonded to the base steel sheet, and even if the resin is partially lost due to scratching after being made into a resin-coated steel sheet, the Ni layer is used to provide excellent corrosion resistance to the steel sheet. It is necessary to form a single layer of a Sn layer, a Fe—Ni alloy layer, a Fe—Sn alloy layer and a Fe—Ni—Sn alloy layer or a film composed of a multilayer thereof.

  This corrosion-resistant film can be formed by a known method according to the contained metal element.

  Excellent wet resin adhesion by forming an adhesion film containing Ti and at least one selected from Co, Fe, Ni, V, Cu, Mn and Zn on this corrosion resistant film Sex is obtained. The reason for this is not clear at present, but it is thought that when such a metal element is incorporated into a film containing Ti, a dense film having a uniform distribution of surface irregularities is formed.

  This adhesive coating contains ions containing Ti, and further cathodic electrolysis in an aqueous solution containing ions containing at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn. Can be formed by processing. At this time, Ti is 0.008 to 0.07 mol / l, preferably 0.02 to 0.05 mol / l, and at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn is Ti. On the other hand, it is possible to use an aqueous solution containing 0.01 to 10, preferably 0.1 to 2.5 in a molar ratio to form a denser and more evenly distributed adhesive film on the surface, and to provide better wet resin adhesion. It is preferable in obtaining.

  Moreover, it is preferable that the adhesive film further contains O. This is because inclusion of O results in a film mainly composed of an oxide of Ti and contributes to wet resin adhesion.

Further, the adhesive film is preferably 3 to 200 mg / m ² per side as the amount of Ti. This is because when the Ti content is 3 mg / m ² or more and 200 mg / m ² or less, the effect of improving wet resin adhesion is sufficiently obtained, and when it exceeds 200 mg / m ² , further improvement in wet resin adhesion cannot be expected, resulting in high costs. It is because it becomes. In addition, the measurement of the Ti amount of the adhesive film can be performed 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 (X-ray photoelectron spectroscopy analyzer).

  As the aqueous solution containing ions containing Ti, an aqueous solution containing fluorotitanate ions or an aqueous solution containing fluorotitanate ions and a fluorine salt 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 after the formation of a corrosion-resistant film in an aqueous solution containing potassium fluoride titanate or an aqueous solution containing potassium fluoride titanate and sodium fluoride forms an efficient uniform film It is possible and preferable.

  The compounds that give ions containing Co, Fe, Ni, V, Cu, Mn and Zn include cobalt sulfate, cobalt chloride, iron sulfate, iron chloride, nickel sulfate, copper sulfate, vanadium oxide sulfate, zinc sulfate, sulfuric acid. Manganese or the like can be used.

Further, Ti is 0.008 to 0.07 mol / l, preferably 0.02 to 0.05 mol / l, and the total amount of at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn is used. In order to adjust the molar ratio of Ti to 0.01 to 10, preferably 0.1 to 2.5, the mass ratio of Ti and metal in the aqueous solution may be adjusted. In the cathodic electrolysis treatment, the current density is preferably 5 to 20 A / dm ² and the electrolysis time is preferably ² to 10 seconds.

2) Resin coated steel sheet (laminated steel sheet)
A resin-coated steel sheet can be produced by coating a resin on at least one surface of the surface-treated steel sheet produced by the method for producing a surface-treated steel sheet of the present invention. As described above, since the surface-treated steel sheet produced by the production method of the present invention is excellent in wet resin adhesion, this resin-coated steel sheet has excellent corrosion resistance and workability.

  There is no limitation in particular as resin coat | covered on the surface-treated steel plate manufactured by 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 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.

  The thickness of the resin coating layer is desirably 3 to 50 μm, particularly 5 to 40 μm. This is because if the thickness is below the above range, the corrosion resistance becomes insufficient, and if the thickness exceeds the above range, problems are likely to occur in terms of workability.

  Formation of the resin coating layer on the surface-treated steel sheet produced in the present invention can be performed by any means. For example, it can be performed 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 a resin on a surface-treated steel sheet in a molten state and thermally bonding the resin. That is, after melt-kneading the resin with an extruder, the resin is extruded from a T-die into a thin film, and the extruded molten resin film is pressed and integrated with a surface-treated steel sheet between a pair of laminate rolls, and then rapidly cooled. To do. When extrusion coating a multi-layer resin coating layer, use multiple extruders for each layer, merge the resin streams from each extruder in a multi-layer die, and then extrude as in the case of a single layer resin. Just coat it. Moreover, a resin coating layer can be formed on both surfaces of a surface-treated steel sheet by passing a surface-treated steel sheet vertically between a pair of laminate rolls and supplying a molten resin web to both sides thereof.

  Such a resin-coated steel sheet can be applied to three-piece cans and seamless cans (two-piece cans) having side seams. The present invention can also 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.

Using plating baths a and b shown in Table 1 on both sides of cold-rolled cold-rolled steel sheets (thickness 0.2 mm) as cold-rolled steel used for the production of tin-free steel sheets (TFS), A corrosion-resistant film is formed by the methods A to D.
A: After annealing the cold-rolled steel sheet at about 700 ° C and performing temper rolling with an elongation of 1.5%, alkaline electrolytic degreasing and sulfuric acid pickling were performed, and then Ni plating treatment was performed using the plating bath a. Form a corrosion-resistant film consisting of the applied Ni layer.
B: Cold-rolled steel sheet is alkaline electrolytically degreased and Ni-plated using plating bath a, then annealed at about 700 ° C in a 10 vol% H ₂ +90 vol% N ₂ atmosphere, and then Ni-plated After diffusing and infiltrating, temper rolling with an elongation of 1.5% is performed to form a corrosion-resistant film composed of an Fe—Ni alloy layer.
C: Alkaline electrolytic degreasing of cold-rolled steel sheet, Ni plating using plating bath a, and then annealing at 700 ° C in 10 vol% H ₂ +90 vol% N ₂ atmosphere After diffusing and penetrating and temper rolling with an elongation of 1.5%, degreasing, pickling, Sn plating using the plating bath b, and heating and melting treatment for heating and holding above the melting point of tin are performed. By this treatment, a corrosion-resistant film composed of an Fe—Ni—Sn alloy layer and an upper Sn layer is formed.
D: Alkaline electrolytic degreasing of the cold-rolled steel sheet, annealing and temper rolling in the same manner as in Condition A, and then Sn plating using the plating bath b, followed by a heat-melting process that heats and maintains the melting point of tin or higher . By this treatment, a corrosion-resistant film composed of the Fe—Sn alloy layer and the upper Sn layer is formed.

  In the treatment of C and D, a part of Sn plating is alloyed by heat melting treatment. Tables 3 and 4 show the amount of pure Sn remaining without alloying.

  Next, on the corrosion-resistant film formed on both surfaces of the steel sheet, cathodic electrolysis is performed under the conditions of cathodic electrolysis shown in Tables 2 to 4, and dried to form an adhesive film, and the surface-treated steel sheets shown in Tables 2 to 4 No. 1 to 31 are prepared. The surface-treated steel sheets No. 1, 16, 19, 22, and 29 are comparative examples in which the adhesive film does not contain Co, Fe, Ni, V, Cu, Mn, and Zn. Nos. 30 and 31 are comparative examples without forming a corrosion-resistant film.

  The Ti amount of the adhesive film is obtained by fluorescent X-ray analysis in comparison with a calibration plate obtained by chemical analysis of the adhesion amount in advance. For the amount of Co, Fe, Ni, V, Cu, Mn, and Zn, select the appropriate measurement method from the same fluorescent X-ray analysis method as that of Ti, chemical analysis, Auger electron spectroscopy, and secondary ion mass spectrometry. Thus, the mass ratio of Co, Fe, Ni, V, Cu, Mn and Zn to Ti contained in the adhesive film is evaluated. Further, O can be confirmed by XPS surface analysis for all of Nos. 1 to 31.

In addition, on both surfaces of these surface-treated steel sheets No. 1 to 31, using an isophthalic acid copolymerized polyethylene terephthalate film having a draw ratio of 3.1 × 3.1, a thickness of 25 μm, a copolymerization ratio of 12 mol%, and a melting point of 224 ° C. Lamination conditions that the degree of biaxial orientation (BO value) is 150, that is, steel sheet feed speed: 40 m / min, rubber roll nip length: 17 mm, lamination time after bonding to water cooling: 1 sec. .1 to 31 are produced. 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. 1-31, the following wet resin adhesiveness and corrosion resistance are evaluated.
Wet resin adhesion: Wet resin adhesion is 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, with both sides on the front and back sides set to n = 1, leaving a film 2 as shown in Fig. 1 (a) and cutting out part 3 of the steel plate 1 , N = 2 for each laminated steel plate), as shown in Fig. 1 (b), attach a weight 4 (100g) to one end of the test piece and turn it 180 ° to the film 2 side and leave it for 30min. This is a film peeling test. Then, the peel length 5 shown in (c) of FIG. 1 is measured and evaluated, and the average of the peel lengths (n = 2) on the front and back surfaces of each laminated steel sheet is obtained. It can be said that the smaller the peeling length 5 is, the better the wet resin adhesion is. However, if the peeling length 5 is less than 10 mm, it is evaluated that the excellent wet resin adhesion intended by the present invention is obtained.
Corrosion resistance: Cut the laminate surface of the laminated steel plate to reach the steel plate substrate using a cutter knife, and immerse it in 80 ml of a test solution in which 1.5% by mass NaCl aqueous solution and 1.5% by mass citric acid aqueous solution are mixed in equal amounts, 55 ° C And left for 9 days to evaluate the corrosion resistance of the cut part (where both the front and back surfaces are n = 1 and n = 2 for each laminated steel sheet) as follows. And
○: No corrosion for n = 2 x: Corrosion occurred at 1 or more of n = 2 Table 5 shows the results. Laminated steel plates Nos. 2 to 15, 17, 18, 20, 21, and 23 to 28, which are examples of the present invention, all exhibit excellent wet resin adhesion and corrosion resistance. On the other hand, the laminated steel sheets No. 1, 16, 19, 22, and 29, which are comparative examples, have no problem with corrosion resistance, but have poor wet resin adhesion, and the laminated steel sheets No. 30 and 31 have wet resin adhesion. There is no problem with the properties, but the corrosion resistance is poor.

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

Claims (2)

  After forming a corrosion-resistant film consisting of at least one layer selected from Ni layer, Sn layer, Fe—Ni alloy layer, Fe—Sn alloy layer and Fe—Ni—Sn alloy layer on at least one surface of the steel plate, Ti is used. And ions containing at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn, and Ti is 0.008 to 0.07 mol / and cathodic electrolysis in an aqueous solution containing at least one metal selected from Co, Fe, Ni, V, Cu, Mn and Zn in a molar ratio of 0.01 to 10 with respect to Ti. A method for producing a surface-treated steel sheet, comprising forming an adhesive film. The method for producing a surface-treated steel sheet according to claim 1, wherein the adhesive film has a Ti content of 3 to 200 mg / m ² per side.

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