Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
  • C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
  • C22F1/04—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon
  • C22F1/053—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of aluminium or alloys based thereon of alloys with zinc as the next major constituent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C51/00—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor
  • B29C51/14—Shaping by thermoforming, i.e. shaping sheets or sheet like preforms after heating, e.g. shaping sheets in matched moulds or by deep-drawing; Apparatus therefor using multilayered preforms or sheets
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C63/00—Lining or sheathing, i.e. applying preformed layers or sheathings of plastics; Apparatus therefor
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B15/08—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
  • C22C21/10—Alloys based on aluminium with zinc as the next major constituent
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2705/00—Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
  • B29K2705/02—Aluminium
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
  • Y10T428/31692—Next to addition polymer from unsaturated monomers

Definitions

• the invention relates to the preparation of an alumimum-plastic laminate for a subsequent forming, for instance into food receptacles, and to the subsequent forming of such receptacles.
• thermoplastic synthetic material such as, for instance polyethylene.
• the metal used in these prior art devices is commercial grade aluminum of a purity of about 98.75 percent, or of aluminum alloys which are non-hardenable. This metal has the disadvantage that it is soft.
• :It is accordingly among the principal objects of the invention to provide for an aluminum-plastic laminate, of which the aluminum layer is composed of an aluminum alloy, and in which a short heat treatment precedes the forming.
• heat treatment may either precede or succeed the laminating step.
• an aluminum alloy sheet metal that has of from 2 t0 8 percent by weight of zinc (with a preferred range of from 2 to 3 percent of zinc) and of from .3 to 5 percent by weight of magnesium (with a preferred range of .3 to 1 percent of magnesium) is hardened by means of solution, annealing, quenching and aging.
• a layer of thremoplastic synthetic sheet To the aluminum sheet there is laminated a layer of thremoplastic synthetic sheet. The heat treatment takes place at a temprerature of at least 180 C. and lasts from a few seconds to about five minutes, and takes place before the forming into receptacles.
• the aforesaid aluminum alloy of 2 to 8 percent by weight of zinc and .3 to 5 percent by weight of magnesium reaches a maximum strength after a hardening treatment, as follows: Solution annealing at a temperature between 350 C. and 500 C. of from one-half hour to one hour, quenching in water or air, and either natural aging at room temperature, or artificial aging at an elevated temperature up to C.
• Solution annealing and quenching may take place at the end of the sheet metal production (the term sheet metal herein including also thin bands, sheets and foil).
• sheet metal herein including also thin bands, sheets and foil.
• the sheet metal begins to harden with attendant deterioration in deformability.
• this heat treatment should preferably be applied immediately before the subsequent forming, as otherwise during continued storing the material would again become hardened. This short term heat treatment is termed hereafter from time to time as recovery.
• the aluminum alloy sheet is laminated with a layer of the aforesaid thermoplastic sheet connected to the aluminum alloy sheet; this lamination may be done in a conventional manner.
• the aluminum alloy sheet may, for instance, be coated with a solution or dispersion of the synthetic material, and thereafter the solvent or dispersion medium be vaporated; alternatively, the plastic material may be applied in sheet form, either by pressure under heat, or emerging out of the melt.
• the aluminum-plastic laminate assembly may then be stored prior to the heat treatment that precedes the forming.
• the laminating without solvent or dispersion medium may, however, be combined with the aforesaid recovery as follows:
• the aluminum alloy sheet may be heated to the temperature needed for the recovery and, while it is still warm, may receive the synthetic plastic sheet layer.
• the forming of the aluminum-plastic laminate assembly of this modified method should, however, follow immediately after the aforesaid laminating step, that means within only a few hours, as otherwise the aluminum alloy will become hard, rendering forming difiicult if not impossible; otherwise, another recovery heating must take place immediately prior to the forming.
• the aforesaid aluminum alloy may, however, receive additional ingredients, as for instance from .1 to .6 percent by weight of manganese, .05 to .2 percent by weight of chromium, and the usual impurities of silicium, iron and copper.
• additional ingredients as for instance from .1 to .6 percent by weight of manganese, .05 to .2 percent by weight of chromium, and the usual impurities of silicium, iron and copper.
• a preferred amount of zinc and magnesium in the alloy is 2 to 3 percent by weight of zinc and .3 to 1 percent by weight of magnesium; these are preferably used in connection with the aforesaid additions and impurities.
• Such an alloy is better formable than a higher alloyed aluminum.
• thermoplastic sheet there is preferred polyolefines, such as polyethylene and polyisobutylene.
• the recovery temperature should be at least 180 C., so as to achieve a stretch gain that is sufiicient for the deforming.
• the upper temperature limit is set on one hand by the disintegrating temperature of the plastic used, and on the other hand should not surpass 280 C., so that subsequently an after-hardening will take place during storing; lastly, it also depends on the duration of the recovery treatment: The shorter the recovery treatment, the higher the temperature that may be used without, however, reaching into the zone where hardening constituents go 'into solution.
• the recovery temperature of an aluminum-plastic assembly in which the plastic is polyethylene preferably is 230 C.
• the duration of the recovery is short, from a few seconds to about five minutes, preferably from one-half to one minute. If the duration is too long, there will either occur warm hardening which influences the deformability adversely, or the ageability during the subsequent storing will be adversely aifected.
• This metal sheet was solution annealed for two minutes at a temperature of 450 C., and thereafter quickly quenched in air. The laminating was done by applying to said sheet metal a polyethylene sheet of 70 ,um. thickness; it was applied under pressure and heat. During the subsequent cold storing, the hardening commenced at once, so that already after a few days the deformability had deteriorated to such an extent that no tear-free receptacles could be formed. After annealing the yield strength was 4.4 kg. per sq. mm., but after the completed cold hardening four weeks later, the yield strength was 10.9 kg. per sq. mm.
• the laminated and hardened aluminum-plastic laminate assembly was subjected to a recovery treatment that lasted 30 seconds, at a temperature of 230 0.; this resulted in a reduction of the yield strength to 5.5 kg. per sq. mm.
• injury free receptacles could be built during a few hours after the recovery treatment.
• the polyethylene layer melted without, however, being detached from the aluminum sheet; on the contrary, the adhesion of the two layers was better after the subsequent cooling-01f than before.
• the plastic layer is subjected to tensions which may yield to find tears in the plastic; such tears might during sterilization of the container lead to at least a partial detachment of the plastic layer from the metal. It has been found, however, that these defects may be avoided if after the forming of the container, the container is subjected to a heat treatment during which the plastic layer Will fuse onto the metal layer. For polyethylene, such a heating step may be carried out for one minute at C.
• the instant invention is particularly suitable for the production of receptacles made from metal-plastic laminates of the instant type, for the reception of food stuffs.
• the forming of the receptacles may be done in a simple manner in a continuous operation, by unwinding the aforesaid metal-plastic laminate assembly off a roll, being placed in front of the recess of a die, and pressed thereinto by compresed air; reference is again had to the aforesaid application Ser. No. 464,523.
• the receptacles are preferably produced in the food process plant immediately before the filling and closing.
• the laminates in accordance with the instant invention are delivered to the food processor, and are subjected to the recovery treatment immediately before the forming of the containers. Owing to the hardening during the normal storing thereafter, there are achieved stable packages which may be subjected to a sterilization operation.
• a method of preparing, for a subsequent forming operation, a formable laminated double layer assembly including an aluminum alloy sheet layer and a thermoplastic synthetic layer joined thereto comprising adding to an age hardened metal sheet which is composed of an aluminum alloy having of from about 2 to about 8 percent by weight of zinc and of from about .3 to about 5 percent by weight of magnesium hardened by solution annealing, quenching or aging, a layer of said plastic material and, immediately prior to the forming, subjecting at least the aluminum alloy sheet layer to a heat treatment lasting from about a few seconds to about five mintues at a temperature of at least C., whereby there will take place a reduction in the yield strength of the metal as compared to its initial age hardened yield strength, and subsequently forming the laminate.
• an age hardened metal sheet which is composed of an aluminum alloy having of from about 2 to about 8 percent by weight of zinc and of from about .3 to about 5 percent by weight of magnesium hardened by solution annealing, quenching or aging, a layer of
• the steps comprising first adding the layer of thermoplastic material to the aluminum alloy sheet and subsequently subjecting the laminated assembly to the heat treatment until the synthetic material commences to disintegrate.
• the steps comprising first adding the layer of thermoplastic material to the aluminum alloy sheet and subsequently heat treating the assembly until the plastic layer at least partially fuses to the aluminum alloy sheet.
• the steps comprising heat treating the aluminum alloy sheet and laminating onto the still warm aluminum alloy sheet the thermoplastic sheet as the thermoplastic sheet emerges from the melt.
• the steps comprising heat treating the aluminum alloy sheet, and pressing the thermoplastic layer as a sheet onto the still warm aluminum alloy sheet.
• said aluminum alloy having of from about 2 to about 3 percent by weight of Zinc and of from about .3 to about 1 percent by weight of magnesium.
• thermoplastic sheet material being polyethylene

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Organic Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Manufacturing & Machinery (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Laminated Bodies (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Containers Having Bodies Formed In One Piece (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (5)

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Citations (9)

• 0
  • GB GB1053040D patent/GB1053040A/en not_active Expired
• 1964
  • 1964-09-29 CH CH1266564A patent/CH423559A/de unknown
• 1965
  • 1965-09-22 DK DK485265AA patent/DK117678B/da unknown
  • 1965-09-23 DE DE19651571197 patent/DE1571197A1/de active Pending
  • 1965-09-27 US US490646A patent/US3444022A/en not_active Expired - Lifetime
  • 1965-09-28 NL NL6512561A patent/NL6512561A/xx unknown
  • 1965-09-28 SE SE12568/65A patent/SE317306B/xx unknown

Patent Citations (9)

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