Method for slitting a film
AssigneeConsolidated-Bathurst Limited
InventorLeo Blais
Life of this patent
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Abstract
A method and apparatus for slitting a moving thermoplastic film. A rotating slitting roll, provided with a plurality of spaced-apart heated blades circumferentially arranged in a pattern, presses the film against a backing member while the film is under tension and in line-contact with the roll. The pressure and heat of the blades fusion-slits the moving film, which may then be stretched to spread the slits and in the case of orientable film to orient the film in the direction of stretch. The slits may be made in either the machine or cross-machine direction. Where continuous slits are made, tapes or ribbons are formed. Where the slits are discontinuous, an aperture film results.
Claims9
A method for the continuous production of an apertured sheet of a thermoplastic polymeric material comprising
- a. providing a slitting means comprising a rotatable slitting roll and a backing roll having their longitudinal axes parallel;
- said rolls being spaced to provide a nip therebetween, said slitting roll having a plurality of spaced apart slitting blades extending from the circumferential surface of said slitting roll, said backing roll having a heat resistant, resilient circumferential surface,
- b. heating said slitting blades such that at least the cutting edges have a temperature above the softening temperature range of said thermoplastic polymeric material,
- c. feeding an unoriented film of said thermoplastic polymeric material under tension through said nip,
- d. pressing the film in said nip against said backing roll with the heated cutting edges of said blades, whereby said blades penetrate and fusion-cut corresponding slits in said film, and
- e. stretching said film such that the resulting slits open to form apertures.
Dependencies are inferred from the claim text.