JP5033341B2 - Correction method for weld can welds - Google Patents

Description

The present invention relates to a method for correcting a weld can weld .

  Conventionally, when a metal plate material is rounded into a rectangular tube shape or a cylindrical shape and formed into a can body, the can body has been joined with solder, an adhesive, etc., but in recent years, considering the strength and cost, welding Has come to be used frequently. In these welded cans, a metal plate material is previously coated with a paint or coated with a resin film except for a portion to be welded. Welding is mainly performed by electric resistance seam welding. Due to the effect of heat on the resin film and the level difference and burrs of the weld, paint is applied to the weld joint and the vicinity of the joint, or the resin film is applied. It is indispensable to cover and correct.

  When correcting the welded part by covering the resin film, a correction tape made of a thermoplastic resin film is overlaid on the heated welded part so as to facilitate thermocompression bonding, and then a pressure-bonding roll is brought into contact and pressure-bonded. Done. In a can that is coated with a resin film by coating paint or laminating a resin film on a portion other than the welded portion, especially when the coating film or the resin film is made of a thermoplastic resin, the welded portion is heated. The nearby coating film or resin film may be heated to around the melting temperature.

  In such a situation, when a flat plate-shaped correction tape at room temperature is placed on the welded portion, first, the correction tape 1 comes into contact with the resin film 2 of the can 10 at both ends in the width direction, as shown in FIG. Next, as shown in FIG. 2, when the pressure-sensitive roll 5 is brought into contact with the correction tape 1 and pressed to press the correction tape 1 to the surface of the can 10, the contact portions at both ends of the correction tape 1 become the resin film 2 along with the pressure. The top moves in the direction of the arrow along the curvature of the cross section of the can body 10. At this time, if the portion of the resin film 2 that is in contact with both ends of the correction tape 1 is heated to around the melting temperature and is in a molten or semi-molten state, it is scraped off by both ends of the correction tape 1. Then, the metal exposed portion 6 is generated. When such a metal exposed portion 6 is generated, the metal plate 3 may be corroded to be perforated when the obtained can body is filled with corrosive contents. Further, when the correction tape 1 is pressure-bonded to the surface of the can body 10, when the pressure-sensitive roll 5 is brought into contact with the correction tape 1 and is simply pressed, bubbles remain in the correction portion, so that the metal portion is exposed and obtained. When the corroded contents are filled in the formed can body, the metal plate 3 may be corroded and lead to perforation.

  In order to overcome these drawbacks, for example, Patent Document 1 discloses a correction tape 1 whose cross-sectional shape is a U shape as shown in FIG. 3A, a V shape as shown in FIG. The metal exposed portion 6 is generated by being scraped off by both end portions of the correction tape 1 by using a bent shape that is a combination of a U-shape and a V-shape as shown in 3 (c). We propose a technology to prevent this. However, when the correction tape 1 is bent in this way, the correction tape itself is damaged at the time of bending and the welded portion is not sufficiently corrected, or the bent portion has a streaky appearance after the correction tape is applied. Appears and has the disadvantage of not being aesthetically pleasing.

Prior art document information relating to the present application includes the following.
JP 2004-130363 A

In the present invention, in correcting and pressed by a press roll overlapping the correction tape welded can weld without causing exposed metal plate portion, also corrected. Appearance of a I溶 chastisement welding impairing the an object of the present invention is to provide a part of the correction how.

The method for correcting a welded can welded portion of the present invention is a method of heating a welded can welded portion to a temperature equal to or higher than the glass transition temperature of a resin constituting a correction tape containing a resin material, and then a pair of a member having a convex portion and a member having a concave portion. The convex portion and the concave portion are fitted to each other using a guide and bent to a substantially U shape without bending the correction tape. The correction tape is pressure-bonded.

  The correction tape of the weld can welded portion of the present invention is a correction tape formed by bending in a substantially U shape along the circumferential direction of the weld can. Further, the correction tape guide of the present invention is a correction tape guide used for crimping of a correction tape for crimping a correction tape to a welded can welded portion via a crimping portion, from a pair of a member having a convex portion and a member having a concave portion. The convex portion and the concave portion are fitted to each other to form a substantially U-shaped gap, and a long strip-shaped correction tape is continuously supplied to the substantially U-shaped gap so that the correction tape is substantially U-shaped. Bend to guide to crimping roll. A metal plate formed by painting a paint or coating a resin film in advance except for the planned welded portion is rounded into a rectangular or cylindrical shape, welded and joined to form a welded can, and a heated welded joint and Resin coated on a metal plate by overlapping the correction tape of the present invention in the vicinity of the joint, bending it in a substantially U shape using the guide of the present invention, guiding the correction tape to the pressure-bonding roll, and pressurizing and pressing. The film is not scraped off by both ends in the width direction of the correction film, and a larger pressure is applied at the center to suppress the generation of air bubbles, so that a metal plate exposed part is generated. Therefore, it is possible to correct the weld can weld. Further, since the correction tape is not bent, streaks appear in the correction portion and the appearance is not impaired.

  Hereinafter, the contents of the present invention will be specifically described with reference to the drawings.

  FIG. 1 and FIG. 2 are schematic views showing the steps of the correction method when using the conventional correction tape and pressure roll, respectively, as described above. 3A, 3B, and 3C are also schematic views showing a cross-sectional shape of a conventional correction tape and a situation in which they are stacked on a can body. As the correction tape 1 of this prior art, for example, as shown in FIG. 3 (a), both end portions in the width direction of the tape are bent to the side opposite to the side in contact with the welded can in the bent portion 1a, and the folded portion 1b. Use the one provided with. By bending both end portions in this way, the resin film 2 in which the rounded bent portion 1a without the corner portion is melted or semi-molten, not the end portion cut at an acute angle as shown in FIG. Therefore, even if the contact portion moves on the resin film 2 by applying pressure with the pressure roll 5, the resin film 2 is scraped off and the metal exposed portion 6 is not generated. Even if the resin film 2 is scraped off by the bent portion 1a and the metal exposed portion 6 is generated, the metal exposed portion 6 is covered by the folded portion 1b. Furthermore, since the distance between both contact portions is narrowed by bending both ends of the correction film 1, the distance that the contact portions move on the resin film 2 is also reduced, and the possibility of the metal exposed portion 6 being reduced accordingly. It will also do.

  However, the correction tape 1 has a U shape as shown in FIG. 3A, a V shape as shown in FIG. 3B, and a U shape and a V shape as shown in FIG. When bent into a shape that combines the shapes, the correction tape 1 itself is damaged by the bending process, and the welded portion is not sufficiently corrected. Also, after applying the correction tape, the folded part appears as a streak-like appearance, which is not aesthetically pleasing.

  In the present invention, a member 21 having a substantially U-shaped convex portion 21a as shown in FIG. 4 and a member 22 having a substantially U-shaped concave portion 22b as shown in FIG. 6 are shown in FIG. As shown in FIG. 8, the correction tape guide is formed such that the member 21 having the cross section of the convex portion 21a and the member 22 having the cross section of the concave portion 22b shown in FIG. 7 are fitted together to form a substantially U-shaped gap. A correction tape 1 having a substantially U-shaped cross section is formed by inserting the correction tape 1 into the substantially U-shaped gap.

  The weld is corrected as shown in FIG. In other words, the welded portion 4 of the welding can 10 is heated to the glass transition temperature of the resin constituting the correction tape 1 or higher, and the long strip-shaped correction tape 1 is continuously supplied from a supply means (not shown) to have a convex portion. After the correction tape 1 having a substantially U-shaped cross-section is inserted into a substantially U-shaped gap of a guide formed by fitting a member 21 having a concave portion 21 and a recess 22, Guide and crimp with a crimping roll. In this way, the weld can of the present invention can be obtained.

  Since the correction tape 1 bent in a substantially U shape in this way is guided and pressure-bonded to the welded portion, the resin film is hardly scraped off, and the metal exposed portion is not generated. Further, since the correction tape 1 is not subjected to a process of bending the cross-sectional shape such as a U-shape or a V-shape in advance, the correction tape 1 is not damaged by the processing, so that the welded portion can be sufficiently corrected. it can. Further, since the bent portion does not appear as a streaky appearance after the correction tape is applied, a preferable appearance can be obtained.

As the metal plate used as the can of the present invention, various metal plates, particularly various surface-treated steel plates are used. As the surface-treated steel sheet, cold-rolled steel sheet is annealed and then secondary cold-rolled, galvanized, aluminum plated, zinc-aluminum alloy plated, tin plated, nickel plated, tin-nickel alloy plated, electrolytic chromic acid treatment, chromium A steel sheet or the like subjected to one or more chemical conversion treatments such as acid treatment can be used. But one example of a suitable surface-treated steel plate having an electrolytic chromic an acid treated steel sheet, in particular a chromium oxide layer of 10 to 200 mg / ^{m 2} of metallic chromium layer and 1 to 50 mg / ^{m 2} (reckoned as metal chromium) In particular, the combination of adhesion to the resin film and corrosion resistance is excellent.

Another example of a suitable surface-treated steel sheet is a tinplate having a tin plating amount of 0.6 to 11.2 g / m ² . This tinplate is preferably subjected to chromic acid treatment or chromic acid / phosphoric acid treatment with a chromium content of 1 to 30 mg / m ² in terms of metallic chromium. As still another example, a surface-treated steel sheet having a metal chromium layer and a chromium oxide layer which are tin-plated in an island shape on a steel sheet and then subjected to electrolytic chromic acid treatment can be used. The thickness of these metal plates is generally 0.17 to 0.6 mm, particularly preferably 0.25 to 0.4 mm, although it depends on the type of metal plate, the use of the can, and the size of the can.

  The metal plate for molding the can body is coated in advance by applying a paint or laminating a resin film except for the portion to be joined by welding. Therefore, it is preferable that the resin constituting the correction tape has good adhesion to the paint constituting the metal plate and the resin constituting the resin film, and may be an unstretched film or biaxial. It may be a stretched film.

  As a welding method for joining the metal plates after rounding them into a rectangular tube shape or a cylindrical shape, a known electric resistance welding method can be used. That is, the opposing edge portions of the joint are electrically resistance welded using the opposing electrode rollers or electrode wires supported by the electrode rollers. The welding atmosphere may be an inert atmosphere such as nitrogen or argon.

  When the can body is coated with a resin film, a thermoplastic resin such as low-density polyethylene, high-density polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, or ethylene, propylene, 1-butene, 4- Polyolefins such as random copolymers or block copolymers of α-olefins such as methyl-1-pentene, ethylene / vinyl acetate copolymers, ethylene / vinyl alcohol copolymers, ethylene / vinyl chloride copolymers, etc. Ethylene / vinyl compound copolymer, polystyrene, styrene resin such as acrylonitrile / styrene copolymer, ABS, α-methylstyrene / styrene copolymer, polyvinyl chloride, polyvinylidene chloride, vinyl chloride / vinylidene chloride copolymer , Polymethyl acrylate, polymethacrylate Polyvinyl compounds such as nylon, polyamides such as nylon 6, nylon 6-6, nylon 6-10, nylon 11 and nylon 12, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyphenylene oxide and the like are used. The resin constituting the correction tape used in the present invention preferably has good adhesiveness with the above-mentioned resin coated on the can body, and is appropriately selected from the above-mentioned resins according to the resin coated on the can body. Is preferred.

  As the resin for covering the can, a polyester resin is often used from the viewpoint of characteristics and cost. In this case, the resin used for the correction tape is also preferably a polyester resin. These polyester resins are preferably homopolyesters or copolymer polyesters derived from dibasic acids mainly composed of terephthalic acid and diols mainly composed of ethylene glycol. Dibasic acids other than terephthalic acid include isophthalic acid, P-β-oxyethoxybenzoic acid, naphthalene-2,6-dicarboxylic acid, diphenoxyethane-4,4′dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydro Examples include terephthalic acid, adipic acid, and sebacic acid. Examples of diol components other than ethylene glycol include propylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, cyclohexane dimethanol, and ethylene oxide adducts of bisphenol A. The glycol component can be raised. Among these copolyesters, those mainly composed of terephthalic acid and isophthalic acid as the acid component retain the workability and mechanical properties and keep the flavor of the contents filled in the can body unchanged. It is particularly preferable in terms of characteristics.

  Polyester homopolymers and copolymers must have a molecular weight in a range that can be formed into a film, that is, an intrinsic viscosity, and an intrinsic viscosity Iv measured using a phenol / tetrachloroethane mixed solvent is It is preferably in the range of 0.5 to 1.6, particularly 0.6 to 1.5. Films formed from these resins may be unstretched, uniaxially stretched, or biaxially stretched, but those that are biaxially stretched have heat resistance, mechanical strength, and permeation resistance of the contents. Excellent in terms.

These polyester resins may be a single homopolymer or copolymer, or may be a resin obtained by blending two or more of these. Moreover, the multilayer resin which laminated | stacked these 2 or more types may be sufficient.
In general, the thickness of the resin layer covering the metal plate is preferably 10 to 100 μm, and the thickness as the correction tape is preferably 10 to 200 μm. The width of the correction tape must completely cover the welded portion, and further straddle the coating resin layer on both sides of the welded joint, so that no metal exposed portion is generated, and generally has a width of about 10 to 50 mm. Preferably it is.

  In the present invention, a correction tape guide comprising a pair of a member having a convex portion and a member having a concave portion is used, and the convex portion and the concave portion of these members are formed in a substantially U-shaped gap formed by fitting each other. After the correction tape is guided to be a correction tape that is bent in a substantially U shape along the circumferential direction of the weld can, the correction tape is guided to the welded portion and crimped. For this reason, the resin film coated on the metal plate is not scraped off by both ends in the width direction of the correction film, and more pressure is applied at the central portion to suppress the generation of bubbles almost completely. It becomes possible to correct the weld can welded portion without producing the exposed metal plate portion. Further, since the correction tape is not bent, streaks appear in the correction portion and the appearance is not impaired.

Schematic which shows 1 process of the correction method using the conventional correction tape and the crimping | compression-bonding roll. Schematic which shows another 1 process of the correction method using the conventional correction tape and the crimping | compression-bonding roll. (A) Schematic which shows an example of the cross-sectional shape of the conventional correction tape, and the condition in the case of putting it on a can body. (B) The schematic which shows the other example of the cross-sectional shape of the conventional correction tape, and the condition in the case of putting it on a can body. (C) The schematic which shows the other example of the cross-sectional shape of the conventional correction tape, and the condition in the case of putting it on a can. The perspective view of the member which has the substantially U-shaped convex part which comprises the guide of the correction tape applied to the correction method of this invention. Sectional drawing of the member which has a substantially U-shaped convex part which comprises the guide of the correction tape applied to the correction method of this invention. The perspective view of the member which has a substantially U-shaped recessed part which comprises the guide of the correction tape applied to the correction method of this invention. Sectional drawing of the member which has a substantially U-shaped recessed part which comprises the guide of the correction tape applied to the correction method of this invention. Sectional drawing which shows the state which fitted the member which has a substantially U-shaped convex part applied to the correction method of this invention, and the member which has a substantially U-shaped recessed part, and formed the substantially U-shaped clearance gap. The schematic sectional drawing which shows the correction method of the welding can of this invention.

Explanation of symbols

1: Correction film 1a: Bending part 1b: Folding part
2: Resin film 3: Metal plate 4: Welding part 5: Crimp roll 6: Metal exposed part 10: Welding can body 21: Member having U-shaped convex part 21a: Convex part 22: Having U-shaped concave part Member 22b: recess

Claims (1)

Heating the weld can weld to a temperature equal to or higher than the glass transition temperature of the resin constituting the correction tape containing the resin material, and then using a guide comprising a pair of a member having a convex portion and a member having a concave portion, the convex portion and the Welding characterized in that the correction tape is crimped to the weld can welded portion using a crimping roll after the concave portions are fitted to each other and bent into a substantially U shape without being subjected to the process of bending the correction tape. Correction method for can welds.

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