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Method for the manufacture of a paper container

  • US 4,187,768 A
  • Filed: 03/10/1978
  • Issued: 02/12/1980
  • Est. Priority Date: 11/15/1977
  • Status: Expired due to Term
First Claim
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1. A method for the manufacture of a paper container having a substantially non-deformable upper mouth edge comprising the steps of:

  • blanking out a bottom panel component and a body component from a sheet of paper material having a coating of thermoplastic film applied to at least one side of said paper material, said body component having opposite side ends, an upper edge, a lower end and a lower edge;

    downwardly bending the peripheral edge of said bottom panel at right angles to the plane of the bottom panel to form a peripheral flange;

    positioning said peripheral flange of the bottom panel slightly above the lower edge of said container body component;

    rolling said body component so as to bring the opposite side ends of the container body component into slightly overlapping relationship so as to form a container body wall having a side seam extending in a longitudinal direction along the body wall;

    inwardly and upwardly bending the lower end of the container body wall along the peripheral flange of the bottom panel so as to encompass the peripheral flange of the bottom panel to thereby form a bottom seam having said plastic film layer on at least one inner side of said bottom seam;

    ultrasonically welding said bottom seam and said side seam by ultrasonic welding means;

    outwardly curling the upper circumferential edge of said container body portion to form a container mouth edge, said upper circumferential edge being outwardly curled to fold inwardly back on itself with said plastic film layer of said folded back edge being in face-to-face relationship with a surface portion of said upper circumferential edge to form an upper seam; and

    ultrasonically welding said upper seam by using ultrasonic welding means, thereby forming a substantially non-deformable ultrasonically welded upper mouth edge.

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