초록 ▼

Continuous strip closed-bottom open-mouthed packaging bags are produced by continually making, at spaced intervals in a continuous flattened tubular oriented plastic film supply, a transversely extending heat seal to define a bag bottom, and, adjacent each heat seal, perforating the two plies of the

Continuous strip closed-bottom open-mouthed packaging bags are produced by continually making, at spaced intervals in a continuous flattened tubular oriented plastic film supply, a transversely extending heat seal to define a bag bottom, and, adjacent each heat seal, perforating the two plies of the film supply with a blade heated to effect annealing of the edges of the perforations and having a serrated cutting edge with spaced deep recesses to define connecting tabs between perforations.

대표청구항 ▼

A method for making packaging bags of flexible oriented plastic film material comprising the steps of: (a) forming a continuous strand of separable end-connected flexible oriented plastic film packaging bags by (i) advancing a continuous length of flattened flexible plastic film tubing having oppose

A method for making packaging bags of flexible oriented plastic film material comprising the steps of: (a) forming a continuous strand of separable end-connected flexible oriented plastic film packaging bags by (i) advancing a continuous length of flattened flexible plastic film tubing having opposed walls in contact with each other to a bag forming station; (ii) forming, at the bag forming station, a heat seal transversely across the flattened flexible plastic film tubing to seal the opposed walls thereof into a bag bottom; (iii) cutting elongate perforations with a heated blade through said tubing to define interperforation tabs of tubing material linearly aligned with the perforations, tear-directed into the tubing material adjacent said bag bottom, said perforations being substantially parallel to said bag bottom forming heat seal, to form a bag mouth joined to the tubing material adjacent said bag bottom by said interperforation tabs; (iv) annealing the cut edges of said perforations with said heated blade simultaneously with said cutting; (v) repeating the steps (i) and (iv) and (b) tear-removing said bags from said continuous strand.