Linearly easy-to-rupture thermoplastic resin film, and method and device for manufacturing the resin film

US20050233102A1Inactive Publication Date: 2005-10-20KAGAWA SEIJI +1
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
Publication Date
2005-10-20
Estimated Expiration
Not applicable · inactive patent

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Abstract

A method for forming substantially parallel linear scratches on a thermoplastic resin film, comprising bringing the film into sliding contact with a means having a lot of fine projections for forming linear scratches, and pressing the film onto the linear-scratch-forming means from the opposite side of the linear-scratch-forming means by a film-pressing means, in a region in which the film is in sliding contact with the linear-scratch-forming means.
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Description

FIELD OF THE INVENTION

[0001] The present invention relates to a thermoplastic resin film easy to straight tear in one direction, and a method and apparatus for producing such a film. BACKGROUND OF THE INVENTION

[0002] In recent progress of barrier-free items, easy opening is considered to be an important function for wrapping films. Typical methods for making the wrapping bags easily openable include a method of providing the wrapping bags with cutting-start points such as V-shaped notches, etc. in their edge portions (heat-sealing portions), and methods needing no cutting-start points such as a magic cut method, a fancy cut method and a method of providing the wrapping bags with fine pores.

[0003] The magic cut and the fancy cut comprise providing the wrapping bags with fine scratches in their edge portions and bending portions in place of notches. However, even with the magic cut or the fancy cut, it has been difficult to open the wrapping bags straight in directions not aligned ...

Examples

example 1

[0110] A polyester (PET) film having a thickness of 12 μm was brought into sliding contact with a 5-cm-diameter pattern roll with fine synthetic diamond particles having a diameter of 100 μm to produce an easy-to-straight-tear polyester film having linear scratches in its moving direction, under the conditions that the film speed was 50 m / minute, that the peripheral speed of the pattern roll rotating in an opposing direction to the film was 10 m / minute, that the pressure of air blown from a nozzle was 1 kgf / cm2, and that a tension given to the film by nip rolls was 0.5 kgf / cm width.

[0111] A surface of the resultant easy-to-straight-tear polyester film was observed by AFM. FIGS. 16 and 17 are the drawings of AFM images. FIGS. 16 and 17 show different portions of the film, and FIG. 17 shows a cross section of the observed portion. As is clear from FIGS. 16 and 17, linear scratches of 0.1 to 1 μm in depth, 0.5 to 5 μm in width and 10 to 50 μm in interval were formed on the polyester f...