| 摘要 |
1,191,653. Block-bottom bags. UNION CARBIDE CORP. 18 April, 1967 [25 April, 1966], No. 17826/67. Heading B8K. [Also in Division B5] A barrier membrane 20 welded to the underside of a corner flap 12 of a block-bottom prevents the corner flap welding to the underlying side walls. The side flaps 16, 18 are subsequently welded to each other and to the corner flap. The side flaps may be folded over a forming platen which supports them while they are welded together, the weld to the corner flaps being made after removal of the platen. The barrier membrane 20 may consist of a polyethylene-polypropylene laminate with the polyethylene layer directed outwardly. Alternatively the membrane may be of polyethylene coated with polyethylene terephthalate, or of aluminium foil coated with a carboxylated olefin polymer. |
