Cloth-like polymeric film with directional tear
Assignee3M Innovative Properties Company
InventorsKo Shiota, Joel A. Getschel, Mark A. Strobel, Michael J. Ulsh, Terry R. Ray
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Abstract
A polymeric film having a plurality of perforations, which are specially structured and arranged is described. The polymeric film provides a strong, high-tensile strength material that permits hand tearing of the film along a desired tear path, providing a controlled tear propagation line. The polymeric film may also be incorporated into a multi-layer film having cloth-like properties of strength and tear propagation, and is suitable for use various adhesive tape applications. Methods of making the polymeric film are also disclosed.
Claims32
An oriented web of polymeric film comprising:
- a first and second surface and;
- a plurality of perforations in the polymeric film extending through the first and second surfaces, arranged in a desired tear path;
- each perforation:
- defining an open area therewithin,
- having a raised ridge at their boundaries;
- and having a shape comprising two ends, a narrow end and an opposite wide end;
- wherein the desired tear path extends through a central portion of the wide end and through the narrow end of each perforation and the narrow end of each perforation being proximal to the wide end of an adjacent perforation along the same desired tear path.
An oriented web of polymeric film comprising:
- a first and second surface
- a pressure sensitive adhesive layer positioned on either first or second surface and;
- a plurality of perforations in the polymeric film extending through the first and second surfaces, arranged in a desired tear path;
- each perforation:
- defining an open area therewithin,
- having a raised ridge at their boundaries;
- and having a shape comprising two ends, a narrow end and an opposite wide end;
- wherein the desired tear path extends through a central portion of the wide end and through the narrow end of each perforation and the narrow end of each perforation being proximal to the wide end of an adjacent perforation along the same desired tear path.
A method of making a polymeric film, the method comprising:
- (a) providing an oriented polymeric film
- (b) perforating the oriented film to form a plurality of perforations in the polymeric film extending through the first and second surfaces, said perforations arranged in a desired tear path;
- each perforation:
- defining an open area therewithin,
- having a raised ridge at their boundaries;
- and having a shape comprising a narrow end and an opposite wide end;
- wherein the desired tear path extends through a central portion of the wide end and through the narrow end of each perforation, to the wide end of an adjacent perforation along the desired tear path.
Dependencies are inferred from the claim text.