US3763895A - Tubular metal can body - Google Patents

Tubular metal can body Download PDF

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Publication number
US3763895A
US3763895A US00153290A US3763895DA US3763895A US 3763895 A US3763895 A US 3763895A US 00153290 A US00153290 A US 00153290A US 3763895D A US3763895D A US 3763895DA US 3763895 A US3763895 A US 3763895A
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United States
Prior art keywords
metal blank
adhesive layer
outside
tubular
metal
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US00153290A
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English (en)
Inventor
M Sasaya
T Toyama
K Okubo
H Ueno
M Tsurumaru
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Toyo Seikan Group Holdings Ltd
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Toyo Seikan Kaisha Ltd
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Priority claimed from JP5351170A external-priority patent/JPS5145267B1/ja
Priority claimed from JP3357271A external-priority patent/JPS5541974B1/ja
Application filed by Toyo Seikan Kaisha Ltd filed Critical Toyo Seikan Kaisha Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L9/00—Rigid pipes
    • F16L9/02—Rigid pipes of metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D51/00—Making hollow objects
    • B21D51/16—Making hollow objects characterised by the use of the objects
    • B21D51/26—Making hollow objects characterised by the use of the objects cans or tins; Closing same in a permanent manner
    • B21D51/2676—Cans or tins having longitudinal or helical seams
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
    • B65D7/02—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by shape
    • B65D7/04—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by shape of curved cross-section, e.g. cans of circular or elliptical cross-section
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D7/00—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal
    • B65D7/12—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by wall construction or by connections between walls
    • B65D7/34—Containers having bodies formed by interconnecting or uniting two or more rigid, or substantially rigid, components made wholly or mainly of metal characterised by wall construction or by connections between walls with permanent connections between walls

Definitions

  • ABSTRACT A tubular metal can body wherein the dissolving of metal in the contents of the can is prevented, said can body comprising a metal blank whose longitudinal marginal portions are joined to each other by a lap side seam through adhesive layers of a thermoplastic organic polymer, said both marginal portions of the metal blank each including two opposing surfaces, a cut end surface and shearing burr projecting from one corner of the cut end portion, said lap side seam being formed by the integral joining of an in-side adhesive layer in a continuous ribbon form of a thickness of from 15 to 200 microns which completely covers both the inner and outer surfaces of the marginal portion of the metal blank located inside the can body, cut end surface and shearing burr and adheres firmly to these surfaces, and an outside adhesive layer in a continuous ribbon form of a thickness of 5 to microns which covers at least the inner surface of the marginal portion of the metal blank located outside the can body and adheres firmly to the surface said outside adhesive layer adhered firmly to the inner surface of the metal blank having a width larger than that of the lap
  • This invention relates to a tubular metal can body in which the marginal portions of a metal blank are joined by a lap side seam through an adhesive layer of an organic polymer, and more specifically, to a tubular metal can body in which the metal is effectively prevented from being dissolved into the contents of the can at the cut end portion of the marginal portion, and also to a method of producing such tubular can body at high speed and with precision.
  • tubular used in the present specification and claims, is meant to express not only a cylindrical form, but also a cross-sectionally elliptical form'or a cross-sectionally polygonal form.
  • Metal can bodies are generally produced by forming a metal blank such as tin plate into a cylindrical shape, and joining the marginal portions by some means.
  • Metal cans which have been most widely used are those produced by joining the marginal portions of a cylindrical body formed from a metal blank such as tin plate by soldering.
  • the tin-free steel represented by steel plate treated electrolytically chromic acid has become available at low cost as a can making material, and has widely superseded the tin plate.
  • This tin-free steel cannot be soldered, and therefore, a technique has been developed for producing can bodies by bonding the marginal portions of this blank with a thermoplastic adhesive such as nylons.
  • hook seam technique which involves forming a rectangular thin sheet as a blank of a can body into a tubular shape, bending both marginal portions along the longitudinal direction in the opposite directions by a known method to form hooks, pouring a heated thermoplastic resin on one of these hooks (generally the hook bent outwardly), engaging it with the other hook while it is still in the plastic state at high temperatures, clamping both hooks tightly by humping, and allowing the thermoplastic resin to cool and solidify, thereby to complete the hook-seam clamping.
  • hook-seam type can body In this hook-seam type can body, the cut end of the marginal portion of a metal blank is embedded in the adhesive, and do not directly contact the contents of the can. Hence, it has the advantage that the metal is not dissolved into the contents of the can. However, the hook portions are readily deformed, and the strength of the joint is limited.
  • Such hook seam type can bodies are unsuitable for use in fields where a high strength of the joint is required, such as-pressure cansfor including beer or soft drinks.
  • Another type of joining in the production of a can body comprises melt-adhering a tape-like thermoplastic organic adhesive to the opposite surfaces of both marginal portions of a rectangular thin metal sheet as a blank, bending the metal blank in a cylindrical shape, heating both marginal portions to which said organic adhesive has been adhered, superposing both marginal portions so that the adhesives on the marginal portions stick to each other, and thereafter bonding the superposed portion, followed by cooling.
  • This lap seam type can body has the advantage that the seam portion has sufficient strength and can withstand use as pressure cans.
  • the cut 'end surface of the metal blank located inside the can body is exposed in its ascut state, corrosion readily develops at the cut end surface.
  • the metal of the blank is readily dissolved into the contents of the can at the cut end surface, and there is a great tendency that the contents will be contaminated or degenerated.
  • a thin metal plate is generally cut by utilizing a shearing force caused by two cutting blades, and at this time, a sharp shearing burr occurs unavoidably.
  • a number of apparatuses have been known to remove the shearing burr, and among the methods of removing it are, for instance, (I) a method of collapsing the shearing burr and (2) a method of filing away the shearing burr.
  • Method (1) is effective for the shearing burr of thick plate, but only results in the changing of the projecting direction of the burr when used to cut a thin sheet.
  • method (2) is used, the protective coating on the surface of the sheet is cut away at the same time, and it is difficult to completely remove iron powders formed at the time of filing.
  • One conceivable method of preventing the cut end portion of a metal blank from being exposed to the inside of the can body comprises forming a metal blank into a tubular can body by the above-mentioned process, and coating a lacquer on the cut end portion exposed at the side seam, thereby to protect it.
  • This method requires a coating step and a step of drying the coating, and the drying step must be carried out at a temperature below the melting point of the adhesive. Lacquers suitable for use in this method are very much limited. Evenwith lacquers which dry at a temperature below the melting point of the adhesive, it is difficult to apply the lacquers only to the cut end portion of the side seam, and in order to protect the cut end portion, the coating of the lacquer should be made thick.
  • a can body is formed by joining both marginal portions of a metal blank with an adhesive, and then a molten thermoplastic resin is poured onto the exposed metal portion inside the seam so as to cover the exposed metal portion.
  • a molten thermoplastic resin is poured onto the exposed metal portion inside the seam so as to cover the exposed metal portion.
  • This portion containing the stepped shoulder is difficult to protect by coating it completely with a melt of a thermoplastic resin which has high viscosity and poor wetting properties.
  • voids occur at the v stepped shoulder portion owing to the thickness of the metal sheet and that of the adhesive layer. If an article is stored in such a can, liquid infiltrates into the voids, and corrodes the exposed metal surface with the lapse of time, which in turn results in the dissolving of metal and after a long time, causes it to dissolve in the article stored.
  • a method of coating the exposed metal portion of the seam of the can body by pouring a lacquer or a molten thermoplastic resin into it cannot be free from such defects as the formation of pin holes at the coated part of the shearing burrs or poor adhesion.
  • an object of this invention is to provide a tubular can body wherein the cut end portion of a marginal portion of the metal blank located inside the can body, especially the cut end surface and the shearing burr, are completely covered with a coating of a thermoplastic organic polymer firmly adhered thereto, and consequently, the dissolving of the metal in the contents of the can is markedly inhibited.
  • Another object of the invention is to provide a method of producing the above-mentioned can body at high speed and without complicated operation.
  • a tubular metal can body wherein the dissolving of metal in the contents of the can is prevented, said can body comprising a metal blank whose longitudinal marginal portions are joined to each other by a lap side seam through adhesive layers of a thermoplastic organic polymer, said both marginal portions of the metal blank each including two opposing surfaces, out end surface and shearing burr projecting from one corner of the cut end portion, said lap side seam being formed by the integral joining of an inside adhesive layer in a continuous tape form ofa thickness from 15 to 200 microns which completely covers both the inner and outer surfaces of the marginal portion of the metal blank located inside the can body, cut end surface and shearing burr and adheres firmly to these surfaces, and an outside adhesive layer in a continuous tape form of a thickness of to I00 microns which covers at least the inner surface of the marginal portion of the metal blank located outside the can body and adheres firmly to the surface said outside adhesive layer adhered .firmly to the inner surface of the metal blank having a width larger than that of the lap side
  • FIG. I is a perspective view of a metal blank to be used for the production of the can body of the present invention
  • FIG. 2 is a perspective view of another metal blank to be used for the production of the can body of the present invention
  • FIG. 3 is a perspective view of the metal blank in an exploded form in which an inside adhesive layer and an outside adhesive layer have been applied to both marginal portions;
  • FIG. 4 is a perspective view showing another embodiment of the metal blank for the production of the can body, which is the same as FIG. 3 except the structure of the outside adhesive layer;
  • FIG. 5 is a perspective view of a tubular can body according to the present invention.
  • FIG. 6 is an enlarged sectional view showing the section in the circumferential direction of the lap side seam of the tubular can body of the invention.
  • FIG. 7 is an enlarged sectional view showing the section in the circumferential direction of the lap side seam of the tubular can body according to another embodiment of the invention.
  • FIG. 8 is a simplified arrangement of an apparatus for applying an adhesive tape which is used in the practice of the method of the present invention.
  • FIGS. 9-A, 9-B, 9-C and 9-D are views explaining the operation of covering the marginal portion of the metal blank with an adhesive tape
  • FIG. 10 is a simplified arrangement of a roll form station for forming metal blank into a cylindrical shape
  • FIG. 11 is a simplified arrangement of a heating station for heating the marginal portions of metal blank formed into a cylindrical shape
  • FIG. 12 is a simplified arrangement of a bumping station for joining the superposed portion of both marginal portions of metal blank.
  • the metal blank to be used in the invention may be any metal blanks used conventionally for the production of can bodies, which include, for example, low carbon steel sheets, low carbon steel sheets whose surfaces have been plated with a metal such as tin, aluminum, zinc or chromium, low carbon steel sheets whose surfaces have been treated with phosphoric acid or chromic acid electrolyticuly or non-electrolytically, and aluminum sheets.
  • a metal such as tin, aluminum, zinc or chromium
  • aluminum sheets may be coated with a primer in order to protect the inner surface of the can body, render the output surface easily printable, and to improve the adhesion at the lap side seam.
  • the metal blanks are used for can making in the form of a rectangular sheet or a long strip.
  • a metal blank 1 includes opposing surfaces 3,3 and a cut end surface 4 at marginal portions 2,2, and also a shearing burr 5 projecting from the corner of the cut end portion which burr is unavoidably formed at the time of shearing the metal blank to the desired size and is not permitted to be removed by any known apparatus. As shown in FIG. 2,
  • a metal blank 1 consisting of a metal sheet 1" and primer coatings 6,6 on the surface thereof, cut end surface 4 and shearing burr 5 at both marginal portions 2,2 are exposed without being covered by the primer coatings 6,6.
  • the shearing burr 5 projects at an acute angle from the surface of the metal, and therefore, pin holes occur in the protecting coating or the adhesion of the coating becomes poor.
  • the cut end surface and shearing burr at the marginal portion of metal blank are firmly adhered to a coating of a thermoplastic organic polymer which acts as an adhesive, and the metal is effectively prevented from exposure.
  • an inside adhesive layer 7 in a continuous ribbon form is provided at the marginal portion 2 of metal blank 1 (for the simplicity of explanation, a metal blank coated with a primer will also be indicated by the reference numeral 1 hereinafter), which adhesive layer completely covers the inner and outer surfaces 3,3, cut end surface 4 and shearing burr 5, and adheres firmly to these surfaces.
  • the inner adhesive layer 7 is a tape of a thermoplastic organic polymer. This tape covers one surface 3 of the marginal portion of the metal blank with a certain width, and the shearing burr 5 projecting from the corner of the cut end portion. It is bent at the comer of the cut endportion so as to cover the cut end surface 4 and also the surface 3 of the marginal portion with a certain width.
  • the thickness of the inside adhesive layer 7 should be l5 to 200 microns, in order to cover the shearing burrs 5 and prevent leakage from the lap side scam in the can end seaming process. If the thickness of the inside adhesive layer is smaller than microns, there is an increasing tendency towards the formation of pin holes in the adhesive layer at the position of the shearing burr, and it is difficult to protect the shearing burr completely. On the other hand, larger thickness of the inside adhesive layer in excess of 200 microns does not give any appreciable increase in coating effect, and is economically disadvantageous. At the same time, there is an increasing tendency towards leakage from the lap side seam in the can end seaming process.
  • the inside adhesive layer is formed by the meltadhesion of the above-described thermoplastic organic polymer tape to the marginal portions of metal blank.
  • the inside adhesive layer consists of a thermoplastic adhesive known per se. Because of relatively low melting point and high bond strength, linear aliphatic polyamides having a relative viscosity (measured with respect to a solution of l g polymer in 100 cc sulfuric acid) of at least l.5 are preferred as the thermoplastic adhesive.
  • the relative viscosity is used herein in an ordinary sense, and is defined as the ratio of the flowing time of a solution of polyamide in 98 percent concentrated sulfuric acid with a polyamide concentration of l g/ 100 cc of sulfuric acid, so that of 98 percent concentrated sulfuric acid as pure solvent, as measured at C. by an Ostwald viscometer.
  • linear aliphatic polyamides useful in the present invention are those having a relative viscosity at 20C. of at least 1.5. Polyamides having a relative viscosity less than 1.5 are not preferred since they are brittle and are poor in their ability to protect the cut end surface,
  • linear aliphatic polyamides used in the invention include nylon-6,6 (polyhexamethylene adipamide), nylon-6,10 (polyhexamethylene sebacamide), nylon-6,12 (polyhexamethylene dodecamide), nylon-6,13 (polyhexamethylene tridecamide), nylon-10,6 (polydecamethylene adipamide), nylon-10,10 (polydecamethylene sebacamide), nylon-10,12 (polydecamethylene dodecamide), nylon-10,13 (polydecamethylene tridecamide), nylon-12,6 (polydodecamethylene adipamide), nylon-12,10 (polydodecamethylene sebacamide), nylon-12,12 (polydodecamethylene dodecamide), nylon-12,13 (polydodecamethylene tridecamide), I nylon-13,6 (polytridecamethylene adipamide), nylon-13,10 (polytridecamethylene sebacamide), I nylon-13,6 (polytridecamethylene adipamide), nylon-13,
  • polymer of omega-aminotridecanoic tures of the polyamides described above and the inter polyamides may also be used.
  • Preferred polyamides are those having low hydroscopicity, and include polyhexamethylene sebacamide, polydodecamethylene adipamide, polydodecamethylene sebacamide, polyhexamethylene tridecamide, polytrideca-methylene tridecamide, polymer of omega-aminoundecanoic acid, polymer of omega-aminododecanoic acid, polymer of omega-aminotridecanoic acid, and interpolymers consisting predominantly of said polyamides,
  • linear polyamides may be used as admixtures, or may contain additives such as plasticizers and heat stabilizers.
  • a metal blank having a primer coating of 2 10 micron thickness As a protective coating.
  • the primer coating used for this purpose may be of any material conventionally used for coating metal sheets for can making, and include, for example, coatings of thermosetting epoxy resins such as combinations of bisepoxy compounds with amines, organic acids, acid anhydrides, phenolic resins, urea resins or polyamide resins.
  • the primer coatings especially preferred in the present invention are the so-called epoxy-phenol resin coatings consisting of resol type phenol resins and epoxy resins.
  • Such epoxy-phenol resins are the precondensation between (A) resol-type mixed phenol resins of mono-functional phenols, namely p-alkylphenols such as p-cresol, and polyfunctional phenols such as phenol, meta-cresol, resorcinol, m-methoxy phenol, m-ethoxy phenol, moctyloxy phenol, p,p'-dihydroxydiphenyldimethylmethane (bisphenol A), the ratio of the monofunctional phenol to polyfunctional phenol being 50:90 to :10, and (B) bis-epoxy compounds consisting of epichlorohydrin and bisphenol A having an epoxy equivalent of 450m 5,500, the ratio of (A) to (B) being 20:80 to 60:40.
  • A resol-type mixed phenol resins of mono-functional phenols, namely p-alkylphenols such as p-cresol, and polyfunctional phenols such as phenol, meta-
  • an outside adhesive layer 8 in the form of a continuous ribbon is provided on the other marginal portion 2' of the metal blank 1 so as to cover at least the inner surface 3 of the marginal portion 2' and adhere firmly thereto.
  • the outside adhesive layer may be provided only on the inner surface 3 in a ribbon form of a certain width from the cut end surface 4 of the marginal portion 2'. It may also be provided as shown in FIG. 4 so as to completely cover the opposing surfaces 3,3, cut end surface 4 and shearing burr at the marginal portion 2' of the metal blank and adhere firmly to these surfaces, just as in the case of the inside adhesive layer 7.
  • the outside adhesive layer 8 is provided only on the inner surface of the marginal portion 2' of the blank, the metal can be effectively prevented from being exposed to the inside of the can body, and there can be obtained sufficient lap joining strength that is endurable in uses as pressure cans.
  • the outside adhesive layer is provided on the entire marginal portion 2' as shown in FIG. 4, it is also possible to prevent the metal from being exposed outside the lap side seam of the can body.
  • the outside adhesive layer is also formed by the hot melt-adhesion of a tape of a thermoplastic organic polymer, and the material same as that of the inside adhesive layer can be conveniently used. It is important that the thickness of the outside adhesive layer should be to 100 microns.
  • the thickness of the outside adhesive layer is smaller than 5 microns, poor adhesion often occurs at points of the lap side seam at the time of high speed can making, namely at the time of producing a can body by bumping overlapping marginal portions of a blank.
  • the thickness of the outside adhesive layer is larger than 100 microns, the contents of a can tend to leak out from the juncture portion of the lap side seam and the closure end which have been double seamed.
  • the adhesive layer should have a sufficient thickness to compensate for the unevenness of the surface of the metal blank in order to cause both marginal portions to adhere firmly to each other irrespective of the uneveness of the surface of the blank at the time of bumping.
  • the thickness of the adhesive layer becomes larger, heat transmission of the adhesive layer becomes poor, in which case it is necessary to heat the marginal portions of the metal blank having the adhesive layer to a higher temperature in order to render the surface of the adhesive layer tacky. If the marginal portions of the metal blank are heated to higher temperatures, cooling of the adhesive layer takes a longer time in the formation of a lap side seam by bumping both marginal portions, and hence, the can-making efficiency is reduced.
  • the outside adhesive layer and the inside adhesive layer are integrated at the lap side seam, heat transmission to the surface of each adhesive layer can be effected easily, and the cycle of heating and cooling the adhesive layers can be performed within a shorter period of time.
  • the tubular can body of the invention is made of a metal blank 1 formed in a cylindrical shape, and both marginal portions 2,2 in its longitudinal direction are joined to each other by a lap side seam integrally united by an inside adhesive layer to cover the inside marginal portion 2 and an outside adhesive layer 8 to cover at least the inner surface of the outside marginal portion 2.
  • the inside adhesive layer 7 and the outside adhesive layer 8 are integrated by melting at their interface 9, and there is no visible boundary line at the lap side seam of the can body.
  • the outside adhesive layer 8 should be provided with a width larger than that of the lap side seam and extend in the circumferential direction beyond the turning point of the inside adhesive layer at the seam portion.
  • outside adhesive layer is retreating from the turning point of the inside adhesive layer, there is formed a small gap surrounded by three surfaces, i.e., the cut end surface of the outside adhesive layer, the turning end of the inside adhesive layer, and the inner surface of the edge of the metal blank, and it frequently becomes difficult to fill this gap completely with a sealing material coated on the closure end. This often becomes a cause of leakage.
  • the positive projection of the outside layer beyond the turning point of the inside adhesive layer ensures complete prevention of the formation of such a gap. Accordingly, leakage from the secured portion between the can body and the closure end can be prevented, and the closure end can be secured to the can body easily without failure.
  • the outside adhesive layer in the circumferential direction it might be possible to extend the outside adhesive layer in the circumferential direction to the other marginal portion of the metal blank to cover the entire inner surface of the metal can body as if with a primer coating.
  • the thickness of the outside adhesive layer overlaps the thickness of the inside adhesive layer, and abrupt changes in the thickness of the can body in the circumferential direction cannot be reduced.
  • the extension in the circumferential direction of the outside adhesive layer should be to a point where it does not contact the inside adhesive layer.
  • the width of the inside adhesive layer may be the same as that of the lap side seam.
  • the outside part of the inside adhesive layer is preferably provided to extend to some extent in the circumferential direction beyond the cut end portion of the metal blank located outside the can body.
  • a method of filling a gap between the stepped shoulder and the closure end by heating this portion at the time of end seaming, and pouring a molten thermoplastic adhesive into the gap. This method may be usable for the end seaming of a can body free from contents, but when the can body contains an article in it, it is difficult to use this method.
  • the preferred dimensions of the individual parts of the lap side seam of the tubular can body of the invention are as follows:
  • Thickness of the metal blank (d)0.l2-0.35 mm 0.13-0.32 mm Thickness of the inside adhesive layer (d,) -200 [1. 30-60 '4. Thickness of the outside adhesive layer (d,) 5-l00 30-80 7.1.
  • the lap side seam of the tubular can body of the invention may be formed so that the shearing burr 5 at the marginal portion of metal blank located inside the can body faces inwardly, and the shearing burr 5"of metal blank located outside the can body faces outwardly.
  • the shearing burr 5 faces outwardly and the shearing burr 5 inwardly as shown in FIG. 7; in other words, the two projecting shearing burrs 5 and 5' at both marginal portions of the metal blank face each other with the inside and outside adhesive layers 7 and 8 therebetween.
  • the arrangement of shearing burrs as shown in FIG. 7 is likely to result in the injury of the surface of metal blank, especially the protective coating when the metal blank is formed into a cylindrical shape and the marginal portions are lapped and joined to each other.
  • the exposure of the shearing burrs can be effectively prevented without involving the above-mentioned defects because the inside marginal portion of the metal blank is completely protected by a coating of the inside adhesive layer, and the outside adhesive layer is provided on theinner surface of the outside marginal portion.
  • the steel sheet so treated was sheared the cut end surface and shearing burr and thus protect them.
  • a film of the same adhesive having a thickness of 60 p. and a width of 6 mm was firmly adhered to one surface of the other marginal portion.
  • the blank was then formed into a tubular shape.
  • the adhesive layers were bonded to each other at 220C., as shown in FIGS. 5 and 7, followed by cooling, to form a can body.
  • the width of the superposed portion was 5 mm.
  • the solids content of the lacquer was 20'percent.
  • the lacquer was coated on the cut end portions, and dried at C. for 5 minutes. In the case of Versalon 1165, it was melted at 200C., and the melt was applied to the cut end portion and then cooled.
  • the can bodies of the invention are useful for various applications. In view of the inhibited dissolution of metal and the freedom from leakage, they are especially useful as cans for foods and drinks. For this purpose, it is preferred to use metal blanks produced by applying a coating of the epoxy-phenol resin on the tinfree steel sheets such as low carbon steel sheet treated with chromic acid.
  • the can bodies having a lap side seam according to the invention find particular utility as pressure cans for including beer or soft drinks;
  • the can body of the invention can be prepared by any desired technique. In a preferred embodiment, it is produced by the method and apparatus to be described below in detail.
  • a method of producing at high speed and with precision a tubular can body wherein both marginal portions of metal blank are joined to each other by a lap side seam through adhesive layers of a thermoplastic organic polymer comprising a. heating both marginal portions of a metal blank by induction heating;
  • both marginal portions of metal blank are heated in order to provide an inside adhesive layer and an outside adhesive layer thereon.
  • a metal strip 1 is continuously fed into an induction heating device I 1, whereby both marginal portions 2 and 2' areheated to a predetermined temperature.
  • the heating of the marginal portions of metal blank may also be performed by contact with gas flame or heated rollers, or by irradiation of an electric heater.
  • the induction heating is superior in that it can selectively heat the marginal portions uniformly to a predetermined temperature.
  • the heating temperature for the marginal portions of the metal blank is the melting point of the thermoplastic organic polymer used as adhesives or higher.
  • An adhesive tape 12 of a thermoplastic resin is fed to one marginal portion 2' heated.
  • the tape is firmly adhered to the top surface of the marginal portion 2' of the metal blank, whereby an outside adhesive layer 8 melt-adhered to the marginal portion 2' is formed.
  • adhesive tape 12' of a thermoplastic organic polymer is fed to one (bottom surface in the drawings) of the inner surface, outer surface and cut end surface of the other marginal portion 2 heated. Only a part of the tape 12' is firmly adhered to one surface of the marginal portion 2 by a pair of the applicator rollers 13. At this time, the press-contact between the adhesive tape 12 and the surface of the marginal portion 2 of the metal blank should be effected at a temperature at which the surface of the adhesive tape contacting the metal blank is melted but the opposite surface of the tape is not substantially melted. This is especially important for adhering the adhesive layer firmly to the marginal portion of the metal blank at high speed and with precision, and for avoiding the film damage in the subsequent folding step.
  • This condition can be experimentally determined by adjusting the relative positions of the induction heating device 11, the applicator rollers 13, and folding members 14a, 14b and 140 or by controlling the induction heating temperature.
  • the applicator rollers are cooled for preventing the breakage of the film.
  • An inwardly bending force is applied to the remainder of the tape firmly adhered to one surface of the marginal portion, thereby to form an inside adhesive layer 7 which firmly adheres to and covers the inner and outer surfaces, cut end surface and shearing burr of said marginal portion.
  • the inwardly bending force is successively applied to the adhesive tape projecting from the marginal portion, as shown in FIGS. 8, and 9-A through 9-D.
  • a member having a surface which acts to bend the projecting part of the tape obliquely inwardly in a progressive manner In order to apply an inwardly bending force to the projecting part of the tape, the projecting part is brought into contact with, for instance, a member having a surface which acts to bend the projecting part of the tape obliquely inwardly in a progressive manner.
  • a member consists of a plurality of processing rollers 14a, 14b, 14c mounted at different angles.
  • a first processing roller 14a has an actuating surface inclined at an angle less than 90 to the surface of the metal blank, and causes adhesive tape 12a to adhere firmly to shearing burr 5 of the metal blank (see FIG. 9-B).
  • a second processing roller 14b has an actuating surface substantially at right angles to the surface of the metal blank, and causes adhesive tape 12a to adhere firmly to the cut end surface of the marginal portion of the metal blank (see FIG. 9-C).
  • a third processing roller 14c has an actuating surface inclined at an angle larger than 90 to the surface of the metal blank, and bends adhesive tape 12a to the opposite surface of the marginal portion of the metal blank (see FIG. 9-D).
  • the adhesive tape is then fed through a pair of press rollers 16, and firmly adhered to the surface opposite to the marginal portion of the metal blank (see FIG. 8.).
  • the number of the rollers may be changed so long as they are not detrimental to the folding step.
  • a member for preventing irregular folding for example, roller 15 be provided upstream of the tape folding members 14a, 14b and 14c.
  • a member for preventing irregular folding for example, roller 15
  • moisture gathers in the voids with the lapse of long time, which not only causes rusting or corrosion of metal, but also deteriorates the size precision of blanks generally required in high speed operation.
  • the folding member may be any, for instance, a slot guide having an actuating surface inclined progressively inwardly or an air jet whose jetting angle is inclined progressively inwardly.
  • the metal blank in which the adhesive tapes have been provided at the marginal portions is then fed into induction heating device 17 (FIG. 8), and the adhersion of the inner adhesive layer 7 to the inner and outer surfaces, cut end surface and shearing burr of the marginal portion is completely effected.
  • the adhesive tape used in the invention may conveniently be of linear aliphatic polyamides having a relative viscosity of at least l .5 as described above, and the sizes of this tape are as stated above with respect to the can body of the invention.
  • the linear aliphatic polyamides used for the adhesive tape have a moisture content of not more than l.5 percent by weight, particularly not more than 0.8 percent by weight.
  • the polyamide tape generally has a high moisture content. For example, nylon 6, has a moisture content of above 2.5 percent by weight.
  • the steam bubbles break to cause poor adhesion of the tape to the marginal portions of the metal blank. It also becomes difficult to effect complete coating sufficient to prevent the metal from dissolving in the contents of the can.
  • the moisture content of the tape is adjusted to less than 1.5 percent, especially less than 0.8 percent prior to the melt-adhesion of the tape to the metal blank, for example, by drying with heat under reduced pressure, the adhesion of it to the metal blank and the coating ,can be completely effected.
  • the adhesive tape should be adhered to the heated marginal portion of the metal blank at a temperature at which the surface of the tape contacting the metal blank is melted but the opposite surface of the tape is not substantially melted.
  • a tape of a polymer as meltextruded is directly applied to the marginal portions of a metal blank, the tape sticks and tends to be deformed readily. It is difficult therefore to maintain the tape in an elongated state while folding it gradually over the edge portions of the metal blank, and to effect the coating of the tape on the metal blank with an accurate width.
  • the heating only of the marginal portion of metal blank makes it possible to melt-adhere the tape only at the surface in contact with the metal blank, and leave the other part in an unmelted state.
  • the bending processing of the adhesive tape can be readily performed as mentioned above.
  • the metal blank is then sheared to the desired size, and the can body blank as shown in FIGS. 3 or 4 can be obtained.
  • This can body blank is formed into a substantially tubular shape by a method known per se so that both marginal portions become a lap side seam.
  • can body blank la is fed to a roll form station 18 of the can body maker, and advanced towards a bending guide 20 by a pair of drive rollers 19. By the cooperative action of these members, the blank can be formed into a substantially tubular shape.
  • Both marginal portions of the substantially tubularshaped blank are then heated by induction heating to a temperature sufficient for the adhesive layers to become tacky.
  • the heating is performed by induction heating devices 23 and 24, whereby the marginal portion 2 having the inside adhesive layer and the marginal portion 2 having the outside adhesive layer are heated until they become tacky in heating station 22 shown in FIG. 11 which is provided coaxially with born 21 of roll form station 18.
  • the inside and outside adhesive layers melt-adhered to the metal blanks should have a moisture content of not more than 1.5 percent, especially not more than 0.8 percent, by weight.
  • the inside marginal portion of the can body blank is superposed on the outside marginal portion, and both marginal portions are pressed with cooling, thereby to melt-bond the inside and outside adhesive layers integrally.
  • the can body blank lb (FIG. 11) in which the adhesive layers are sticky is fed to a bumping station 25 provided coaxially with the heating station 22 (FIG. 11).
  • a bumping station 25 one marginal portion 2 of the can body blank 1c supported by mandrel 26 is first urged against the mandrel by a closing mold 27, and then the other marginal portion 2' is urged against the mandrel by a closing mold 28, whereby the marginal portion 2 is superposed on the other marginal portion 2'.
  • a hammer 29 then moves upwards to press the superposed part of both marginal portions of the can body blank 10 to cause the integration of the inside adhesive layer and the outside adhesive layer.
  • a lower spline 32 including a cooling passageway 30 through which to pass a cooling medium, and at the upper portion of the hammer 29, there is provided a cooling passageway 31 through which to pass a cooling medium. These passageways are for the purpose of cooling the integrated adhesive layers at the superposed part.
  • the can body maker consisting of the roll form station and the bumping station is of the conventional type which has previously been used to produce soldered cans.
  • This type of can body maker can be easily moditied for the purpose of this invention by providing the heating station before the bumping station, with induction heating devices 23 and 24 as shown in FIG. 11 secured to the heating station, and also providing cooling means fitted to the hammer and lower spline of the bumping station.
  • This known can body maker is so designed that when a can body blank is fed, the marginal metal blank can be performed within a short time of 30 to 200 milliseconds. This is because the inside and outside adhesive layers are provided at both marginal portions of the metal blank and the adhesive layer is firmly adhered to the marginal portion of the metal blank located inside the can body.
  • a tubular metal can body wherein the dissolving of metal in the contents of the can is prevented, said can body comprising a metal blank whose longitudinal marginal portions are joined to each other by a lap side seam through inside and outside adhesive layers of a thermoplastic organic polymer; said both marginal portions of the metal blank each including two opposing surfaces, a cut end surface and shearing burr projecting from one corner of the cut end surface; said lap side seam being formed by the integral joining of said inside adhesive layer and said outside adhesive layer; said inside adhesive layer being in a continuous ribbon form of a thickness of from 15 to 200 microns which completely covers both the inner and outer surfaces of the marginal portion of the metal blank located inside the can body, cut end surface and shearing burr and adheres firmly to these surfaces; and said outside adhesive layer being in a continuous ribbon form of a thickness of to 100 microns which covers at least the inner surface of the marginal portion of the metal blank located outside the can body and adheres firmly to the inner surface of the metal blank; said outside adhesive layer having a width larger than that
  • a tubular can body of claim I wherein the outside part of said inside adhesive layer extends in the circumferential direction beyond the cut end portion of the metal blank located outside the can body and firmly adheres to the metal blank.
  • thermoplastic organic polymer is a linear aliphatic polyamide having a relative viscosity, as measured at 20C. in sulfuric acid at a concentration of l g polymer in cc of 98 percent sulfuric acid, of at least 1.5.
  • a tubular can body of claim 12, wherein said polyamide is selected from the group consisting of polyhexamethylene sebacamide, polydodecamethylene sebacamide, polyhexamethylene tridecamide, polytridecamethylene tridecamide, omegaaminotridecanoic acid polymer, polylauryl lactam, omega-aminoundecanoic acid polymer, and interpolyamides of these.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Laminated Bodies (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Lining Or Joining Of Plastics Or The Like (AREA)
  • Rigid Containers With Two Or More Constituent Elements (AREA)
US00153290A 1970-06-22 1971-06-15 Tubular metal can body Expired - Lifetime US3763895A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5351170A JPS5145267B1 (xx) 1970-06-22 1970-06-22
JP3357271A JPS5541974B1 (xx) 1971-05-20 1971-05-20

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US3763895A true US3763895A (en) 1973-10-09

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US00153290A Expired - Lifetime US3763895A (en) 1970-06-22 1971-06-15 Tubular metal can body

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US (1) US3763895A (xx)
CA (1) CA947675A (xx)
DK (1) DK136110B (xx)
FR (1) FR2096413B1 (xx)
GB (1) GB1345049A (xx)
IT (1) IT941569B (xx)
NL (2) NL7108582A (xx)
SE (1) SE393083B (xx)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4023589A (en) * 1974-10-15 1977-05-17 The Wiremold Company Tubular joint and the product formed thereby
US4117188A (en) * 1976-05-17 1978-09-26 Hokkai Can Co. Ltd. Lapped seam can
EP0646428A1 (de) * 1993-09-30 1995-04-05 Elpatronic Ag Verfahren und Anlage zur Innen- und/oder Aussenbeschichtung von Blech für Dosenzargen von Dreiteildosen

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ZA807387B (en) * 1979-12-08 1981-11-25 Metal Box Co Ltd Containers
JPS5852040A (ja) * 1981-09-17 1983-03-28 東洋製罐株式会社 周状側面継目を有する金属製容器及びその製造方法
AU2133883A (en) * 1982-11-16 1984-05-24 Toyo Seikan Kaisha Ltd. Metallic container with circumferential lap bond

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3125056A (en) * 1964-03-17 kaiser
US3213890A (en) * 1961-05-31 1965-10-26 United Shoe Machinery Corp Tubular bodies
US3411542A (en) * 1965-05-17 1968-11-19 United Shoe Machinery Corp Lap seamed tubular container bodies and method for making same
US3437063A (en) * 1965-07-06 1969-04-08 United Shoe Machinery Corp Methods for making container bodies using thermoplastic adhesive
US3550806A (en) * 1966-05-25 1970-12-29 Gen Mills Inc Metallic structures

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE432323A (xx) *
US3508507A (en) * 1967-09-08 1970-04-28 American Can Co Container bodymaker

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3125056A (en) * 1964-03-17 kaiser
US3213890A (en) * 1961-05-31 1965-10-26 United Shoe Machinery Corp Tubular bodies
US3411542A (en) * 1965-05-17 1968-11-19 United Shoe Machinery Corp Lap seamed tubular container bodies and method for making same
US3437063A (en) * 1965-07-06 1969-04-08 United Shoe Machinery Corp Methods for making container bodies using thermoplastic adhesive
US3550806A (en) * 1966-05-25 1970-12-29 Gen Mills Inc Metallic structures

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Southwick, C. A.; Winship, J. T., New Can Constructions in Modern Packaging 43(3): p. 77 81, March. 1970. *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4023589A (en) * 1974-10-15 1977-05-17 The Wiremold Company Tubular joint and the product formed thereby
US4117188A (en) * 1976-05-17 1978-09-26 Hokkai Can Co. Ltd. Lapped seam can
EP0646428A1 (de) * 1993-09-30 1995-04-05 Elpatronic Ag Verfahren und Anlage zur Innen- und/oder Aussenbeschichtung von Blech für Dosenzargen von Dreiteildosen

Also Published As

Publication number Publication date
NL7502858A (nl) 1975-06-30
DK136110C (xx) 1978-01-16
DE2130607B2 (de) 1976-02-19
DK136110B (da) 1977-08-15
IT941569B (it) 1973-03-10
FR2096413A1 (xx) 1972-02-18
SE393083B (sv) 1977-05-02
NL7108582A (xx) 1971-12-24
DE2130607A1 (de) 1972-01-13
CA947675A (en) 1974-05-21
FR2096413B1 (xx) 1975-02-21
GB1345049A (xx) 1974-01-30

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