An easy open closure

Claim 2

An easy open seal for an opening in a receptacle (R) of thermoplastic film (F), said film having at least two layers (2,3),characterised in that the tensile or rupture strength of the outer surface layer (3) is greater than the bond strength between the outer layer (3) and its adjacent layer (2); in that there is at least one fold (12) in said film, said fold being adjacent a film edge (El), said fold (12) providing direct contact between two surface areas of said outer layer (3); in that a seal (S) bonds said two surface areas, said seal being located between said fold (12) and said film edge (El); and in that said fold (12) provides a tab (4) which may be pulled to rupture one of said outer layers (3) at said seal (S) and to cause said outer layer (3) to delaminate from its adjacent layer (2) to the edge (El) of the film (Fl) thereby opening said receptacle (R).

Claim 3

A seal according to Claim 1, characterised in that there are two of said folds (12) providing respective said tabs(4,5) each having an outer layer (3) bonded at said seal (S) such that pulling said tabs (4,5) apart will cause the outer layer (3) of one of them to rupture and to delaminate from its adjacent layer (2).

Claim 4

A seal according to Claim 1 or 2, characterised in that the material of the outer surface layer (3) is polyethylene or an ethylene-vinyl acetate copolymer and in that the material of the adjacent layer (2) is nylon, a vinylidene chloride copolymer, a propylene homopolymer or copolymer, or a cross-linked copolymer of polyethylene and ethylene-vinyl acetate.

Claim 5

A seal according to Claim 1, 2 or 3 characterised in that said film comprises three layers (1,2,3) of which the outer layer (3) is an ethylene vinyl acetate copolymer, the middle layer (2) is a copolymer of vinylidene chloride, and the outer layer (1) is a cross-linked copolymer of ethylene and vinyl acetate.

Claim 6

A package comprising a product (6) within a receptacle (R) of flexible film (F) having at least two layers (2,3) characterised in that one side of said receptacle (R) is closed by a seal according to claim 2, alone or together with either of claims 3 and 4; and in that said seal (S) is formed by opposed ends (Fl,F2) of said receptacle inwardly folded over at coinciding fold lines (12) so that all of said surface-to-surface seals (S) are in-line within the same seal area located between the fold lines (12) and product (6) whereby the folded over edges (Fl,F2) provide said tabs (4,5).

Claim 7

A package according to Claim 5, characterised by further comprising a strip-like dead fold element (7,11) enclosed by at least one of said folds (12) whereby after said bag is opened it may be closed by bending said dead fold element.

Claim 8

A package according to Claim 6, characterised in that said strip-like dead-fold element (7) extends along approximately one-half of said mouth.

Claim 9

A package according to any one of the preceding claims, characterised in that portions (29) have been removed from near the ends of said fold or folds (12).

Claim 12

A method of making an easy open seal according to Claim 9,.characterised by the steps of: providing a receptacle in the form of a side seal bag (R) constructed of flexible thermoplastic film (F) having at least two layers; removing corner portions (27) of said bag (R) adjacent to the end opening of the bag so that two extended lip portions (Fl,F2) are formed; placing a strip-like dead fold element (7) on an inner surface of at least one (F2) of said extended lip portions; folding said extended lip portions (Fl,F2) into said end opening so as to surround and encompass said dead fold element (7) within the fold of the lip portion (F2) on which the element (7) was placed, said folds bringing portions of the outer surface (3) of the bag (R) into direct contact; and then flattening and heat sealing said folded lip portions (Fl,F2) to enclose said dead fold element (7) within its respective fold and to close said bag (R), said heat seal (S) being transverse across the width of the bag and being located between the fold line (12) and the edge (E2) of each of the inwardly folded lips (Fl,F2), said folds providing grippable tabs (4,5) for pulling said folds (Fl,F2) apart to open said bag (R); and further characterised by filling said bag (R) with a product (6) prior to said application of the heat seal whereby an easy open package with a reclosable dead fold closure element (7) is provided.

Claim 13

A method according to Claim 10, characterised in that the seal (S) is formed between the dead fold closure element (7) and the edge (E2) of the lip (F2).

Claim 14

A method according to Claim 10 or 11, characterised by further including the step of punching out portions (24) of the folds at the fold line (12) adjacent the side seal to reduce stress on said side seals.

Claim 15

A method according to Claim 9, characterised by the step of punching a hole (21) through the tab (4) between the fold line (12) and the seal (S) to allow a strip-like dead fold element (7) to be introduced into the interior of the fold of the tab (4), for reclosing of the package after opening of the easy open seal.