Tear resistant separable end-connected bags

Claim 1

A method for making a sheet of flexible oriented plastic film material comprising the steps of: (a) forming a continuous strand of separable edge-connected flexible oriented plastic film sheets by advancing a continuous length of said material to a sheet perforating station; cutting elongate perforations with a heated blade through said material transversely to the direction of its advance; forming interperforation tabs, one between each two of and in linear alignment with said elongate perforations, tear-oriented into one sheet of each two said sheets and connecting each sheet to a contiguous sheet in the strand; simultaneously with forming said tabs annealing the cut edges of said perforations; and (b) tear-removing said film sheets from said continuous strand.

Claim 2

A method for making a sheet of flexible oriented plastic film material comprising the steps of: (a) forming a continuous strand of separable edge-connected flexible oriented plastic film sheets by advancing a continuous length of said material to a sheet perforating station; cutting elongate perforations with a heated blade through said material transversely to the direction of its advance; forming interperforation tabs, one between each two of and in linear alignment with said elongate perforations, tear-oriented into one sheet of each two said sheets and connecting each sheet to a contiguous sheet in the strand; simultaneously with forming said tabs annealing the cut edges of said perforations; and (b) tear-removing said film sheets from said continuous strand.

Claim 6

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.

Claim 7

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.

Claim 8

A method for forming a continuous strand of separable end-connected flexible plastic film packaging bags comprising the steps of: advancing a preselected length of flattened flexible plastic film tubing having opposed walls in contact with each other to a bag forming station; forming a heat seal transversely across the flattened flexible plastic film tubing to seal the opposed walls thereof into a bag bottom; cutting elongate perforations 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 heat seal to form a bag mouth joined to the tubing material adjacent said bag bottom by said interperforation tabs; and simultaneously with forming said tabs annealing the cut edges of said perforations.

Claim 9

A method for forming a continuous strand of separable end-connected flexible plastic film packaging bags comprising the steps of: advancing a preselected length of flattened flexible plastic film tubing having opposed walls in contact with each other to a bag forming station; forming a heat seal transversely across the flattened flexible plastic film tubing to seal the opposed walls thereof into a bag bottom; cutting elongate perforations 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 heat seal to form a bag mouth joined to the tubing material adjacent said bag bottom by said interperforation tabs; and simultaneously with forming said tabs annealing the cut edges of said perforations.