Method and apparatus for making flexible articles having elastic-like behavior with visually distinct regions

Abstract

A method of forming flexible bags from a continuous web is disclosed. The method includes introducing a continuous web of sheet material and passing it through a process whereby the flexible bag is formed having elastic-like behavior. The continuous web is processed into a continuous web having at least two regions that are visually distinct. A sheet material is introduced having one portion of the sheet material overlapping another portion of the sheet material. The sheet material is formed into a strainable network. The strainable network includes a plurality of first regions and a plurality of second regions. The first regions are substantially un-deformed and the second regions are formed into disengageable pleat elements. As the overlapped portions of the sheet material are formed they engage each other at the pleat elements. The pleat elements of each overlapped portion become engaged within each other and resist disengagement because of the frictional forces of the sheet material. The overlapped portions of the sheet material are separated using a disengaging means so that the overlapped portions become disengaged and are separated from each other while riding on the disengaging means. The disengaging means is in the form of either air knife, static opening bar, dynamic opening bar, or suction means, and any combinations thereof.

Description

TECHNICAL FIELD [0001] The present invention relates to a method and apparatus for the production of flexible articles from a continuous web; and more particularly, a method and apparatus for the making of flexible bags having elastic-like behavior is disclosed. BACKGROUND OF THE INVENTION [0002] Flexible articles, particularly flexible bags made of comparatively inexpensive plastic materials, have been widely employed for the containment and / or disposal of various items. As utilized herein, the term “flexible” refers to materials that are capable of being flexed, stretched, or bent, especially repeatedly, such that they are pliant and yieldable in response to externally applied forces. Accordingly, “flexible” is substantially opposite in meaning to the terms inflexible, brittle, or unyielding. Materials and structures that are flexible, therefore, may be altered in shape and structure to accommodate external forces and to conform to the shape of objects brought into contact with th...

AI Technical Summary

Benefits of technology

"The present invention provides a method and apparatus for making flexible articles from a continuous web of sheet material. The process involves forming a strainable network of the sheet material with first regions that are substantially un-deformed and second regions that are formed into disengageable pleat elements. The overlapped portions of the sheet material become trapped within each other and resist disengagement because of the frictional forces and attractive forces of the sheet material. The overlapped portions are separated using a disengaging means, such as a static opening bar, a dynamic opening bar, or a suction means, to form flexible articles like flexible bags."

Problems solved by technology

One problem that arises when making flexible bags from a film formed in this manner is that, if the film has at least one overlapped layer or is made in a tubular manner, when having deformations formed therein, one layer becomes engaged within the other and is difficult to separate for subsequent processing.

A similar problem arises when films such as thermoplastic elastomeric films exhibit excessive blocking characteristics.

It is frequently difficult to separate the overlaying or overlapping layers of film in which deformations have been formed which can cause problems during subsequent processing.

This problem is even more acute when the continuous web from which the flexible bags are made is not in a tubular configuration that can be easily inflated using air.

In these instances, inflating the continuous web using air is not a practical method to separate the overlapping layers since the air has a tendency to escape through the open edge opposite the fold.

Even when a tubular configuration of continuous web is used, an air bubble can have a tendency to leak air out through the deformations or creases formed in the continuous web.

Images