US 4,606,784 A · Method and an arrangement for the folding and sealing of the longitudinal edge of a material web

Abstract

In the manufacture of packing containers from laminated material contact between the inner layer of the material and the contents is avoided by doubling up the cut edges present in the packing container. It has proved to be difficult to perform a secure folding and sealing of the folded edge without damage to the material, since the outer, water-tight layer of the material consists of very thin, heat-sensitive thermoplastic. This difficulty is overcome by carrying out the folding and sealing of the edge of the material web gradually while at the same time supplying heat or glue. By supplying the sealing-promoting agent as late as possible during the course of folding, damage to the material as well as to the folding arrangement is avoided.

Claims15

Dependent claims

A method of forming a folded edge in a packing web having an exterior layer of thermoplastic material, so that an edge zone of the web is folded flat against a zone bordering said edge zone along a fold-line, comprising the steps of:

continuously feeding the material web;
progressively folding said edge zone by steps until said edge zone has been folded approximately 90.degree. relative to said bordering zone with said thermoplastic layer disposed inside of the 90.degree. fold;
supplying heat to the inside of the 90.degree. fold along said edge zone and said bordering zone while maintaining said edge zone folded at approximately 90.degree.;
further progressively folding said edge zone by steps until said edge zone has been folded approximately 180.degree. relative to said bordering zone;
and
pressing said edge zone against said bordering zone so as to thermally seal the edge zone to the bordering zone.

3 more elements

An arrangement for manufacturing a packing web with an edge zone of the web folded flat against a zone bordering said edge zone along a fold-line, said web having an exterior layer of thermoplastic material, said arrangement comprising:

means for feeding said material web along a path;
prefolding means along a first length of said path for progressively folding said edge zone by steps until said edge zone is folded at approximately 90.degree. relative to said bordering zone with said thermoplastic layer disposed inside of the 90.degree. fold;
means for maintaining said edge zone folded at approximately 90.degree. along a second path length subsequent to said first path length;
means along said second path length for supplying heat to the inside of the 90.degree. fold along said prefolded edge zone and said bordering zone;
means along a third path length subsequent to said second path length for further progressively folding said edge zone by steps until said edge zone has been folded approximately 180.degree. relative to said bordering zone;
and
means along a fourth path length subsequent to said third path length for pressing said edge zone against said bordering zone so as to thermally seal said edge zone to said bordering zone.

4 more elements

Dependencies are inferred from the claim text.

Method and an arrangement for the folding and sealing of the longitudinal edge of a material web

Life of this patent

Method and an arrangement for the folding and sealing of the longitudinal edge of a material web

Life of this patent

Abstract

Claims15