Patent ID: 6503440
Filing Date: 2003-01-07
Classification: B29C,B29L,B65D,Y10S,Y10T

Abstract:
A process for the production of a container having a container opening, the container having substantially rigid outer container having an inner surface and an outer surface and an inner bag having an inner surface and an outer surface disposed therein, the outer container having a pressure equalization opening in a base area thereof for equalizing a pressure difference between the outer container and the inner bag, wherein the outer container and inner bag respectively comprise different thermoplastic plastics not bonded to each other, the process comprising:coextruding a preliminary moulding having an inner surface and an outer surface from an inner coaxial tube and an outer coaxial tube having sufficient length for manufacture of the container using a blow mould having interior surface contours, to form an outwardly-projecting base seam in the preliminary moulding and to compress excess material in a base area of the preliminary moulding such that: (i) material of the outer coaxial tube in contact near the base seam is welded together, (ii) the inner coaxial tube forming the inner bag is clamped, axially fixed, and welded between the wall sections of the outer container, and (iii) the inner bag is subjected to pressure so that the outer surface of the preliminary moulding lie against the interior contours of the blow mould, wherein on closing the blow mould and with the associated formation of the base seam, the outer surface of the inner bag is at least partially fixed axially by the inner surface of the outer container and at least one pressure equalization opening is formed in that the base seam is at least partially cut off after shaping, and a radial force which acts in the direction of the base seam is exerted in the base area in such a way that the base seam breaks open, and wherein the temperature of the preliminary moulding is between 40Â° C. and 70Â° C. when the base seam is cut off and the outer container is still plastically deformable to some degree, so that a permanent deformation results from the force which is not neutralized by elastic restoration.