Cheap, strong sack of tubular textile of woven oriented polymer strips - has box-like end made from folded flaps with hole in overlapping area for bonding with polymer, esp. polyolefin melt

摘要

A woven textile sack of monoaxially-oriented polymer esp. polyolefin strips, as in AT400831, consists of tubular fabric or flat fabric bonded to form a tube. One or both sides may be coated with thermoplastic resin, esp. polyolefin, and at least one end of the esp. box-like sack is folded to a rectangular end surface. At least one end is hot bonded to a covering sheet of similar fabric by an intermediate layer of thermoplastic resin, esp. polyolefin, so that only the outer part of the surface, esp. less than 30% of the thickness of the strips forming the outer fabric and the flap at the end has polymer mols. disoriented by heating, whilst the rest of the mols. are oriented. The improvement is that at least one opening is made in the area between the inside edge (5") of the narrow flap and the inside edge (2') of the valve between the narrow (5') and long (4, 5) flaps. Also claimed is a method of welding a covering sheet to one end of a sack of this type.