WO1995009727B1

WO1995009727B1 - Bags and method of making bags

Info

Publication number: WO1995009727B1
Application number: PCT/US1994/011346
Authority: WO
Filing date: 1994-10-06
Publication date: 1995-04-27

Abstract

Methods of making a container strip in the form of a chain of interconnected preopened bags with openings preferably having longitudinal dimensions of at least about 1/64 inch is disclosed. The container strip provides greatly enhanced facility for bag registration and opening during packaging operations utilizing the improved container strip. Processes of forming a chain of preopened bags are also disclosed. Face (14) and back (5) plastic webs are fed along individual paths of travel to a common path (28). In one embodiment the webs are differentially tensioned while in their independent paths by stretching the face web, by rollers (18) more than the back web by rollers (20) such that the face web will retract longitudinally more than the back web upon release of the web tension. While so tensioned edge seals are formed between the webs to convert the webs into a tube and longitudinally spaced transverse seals are formed between the webs to delineate bottoms of bags. Transverse lines of weakness are formed in said back web to facilitate separation of bags from the remainder of the web during a subsequent use. Tension in individual bag sections of the face web is released by forming longitudinally spaced transverse separations of the sections and thereby producing a space between each contiguous pair of sections. In other embodiments, pairs of transverse lines of severance are formed in a front section of the webs and parts between the lines of severance are removed to form the novel bags without the need for differential stretching.

Claims

AMENDED CLAIMS

[received by the International Bureau on 30 March 1995 (30.03.95); original claim 29 amended; new claims 43-46 added; remaining claims unchanged (3 pages)]

28. The process of Claim 24 wherein the differential stretching is achieved while the webs are in their independent paths.

29. A process of forming a chain of interconnected and pre-opened bags comprising: a) feeding a bag face web along an independent path of travel to a joint path of travel; b) feeding a bag back web along a different independent path of travel to the joint path; c) tensioning the webs as they are fed along their respective independent paths to differentially stretch the webs with the face web being stretched more than the back web; d) forming side seals between the webs while so differentially stretched to form a tube; e) delineating bag bottoms by forming transverse, longitudinally spaced seals between the webs; f) forming face and back web pairs of transverse lines of weakness at longitudinally spaced locations with each pair of lines delineating a bag top; g) zinging sections of the face web forming bag faces to tear the face web perforations and thereby open each bag; and h) releasing the web tension to allow the inherent resiliency of each web to achieve an unstretched condition and thereby produce a space between each bag face and its adjacent bag end whereby to provide a chain of easy open bags with easily detectable lines of weakness.

30. The process of Claim 29 wherein each such space is at least 1/64 inch in dimension longitudinally of the web. 40. The strip of claim 38 wherein one of the plies is pigmented and the other is clear.

41. The strip of claim 40 wherein the pigmented ply is translucent.

42. The strip of claim 40 wherein the pigmented ply is opaque.

43. A process for forming an elongate chain of interconnected, preopened, plastic bags comprising: a) forming an elongate flattened tube having juxtaposed face and back plies; b) forming a series of spaced, bag bottom delineating, transverse seals between the plies; c) forming transvers ines of weakness in the back ply spaced from one another at intervals corresponding to the spacing between the seals, eε^h of the lines of weakness being near one of the seals to delineate ends of two contiguous bags being formed; d) forming bag openings in the front ply, each bag opening being aligned with an associated one of the lines of weakness with each opening extending longitudinally of the web in both directions from its associated line of weakness a distance sufficient to assure detector access to the associated line of weakness; and, e) collecting a quantity of the formed interconnected bags into a dispensing arrangement comprised of a selected one of a coil and a festooned array.

44. The process of Claim 43 wherein the longitudinal dimension of each opening is at least about 1/64 inch.

45. The process of Claim 44 wherein each opening is substantially longitudinally symmetrical of its associated line of weakness. 46. The process of Claim 43 wherein each opening is substantially longitudinally symmetrical of its associated line of weakness.

STATEMENT UNDER ARTICLE 19

The amendment of aim 29 and addition of claims 43-46 is made so that these claims conform to claims allowed in the corresponding U.S. case. Claims 24-32 and 43-46 now conform exactly to the allowed U.S. claims, the only difference being recitation of "1/64 inch" instead of "1/32 inch".