Apparatus for manufacturing and processing pre-stretch films having strips of increased thickness
AssigneeDavis-Standard, LLC
InventorsHassan Helmy, Robert F. Moeller, John P. Christiano, Daniel F. Hould
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Abstract
A method for maximizing a width of a pre-stretch film includes providing polymer being suitable for producing the pre-stretch film. A pre-stretch film having strips of increased thickness is produced. The method includes coordinating a thickness of the strips of increased thickness with a formation of edge thickening caused by neck-in during stretching of the pre-stretch film.
Claims28
A method for maximizing a width of a pre-stretch film, the method comprising:
- providing polymer being suitable for producing the pre-stretch film;
- producing a pre-stretch film with strips of increased thickness;
- and
- coordinating a thickness of the strips of increased thickness with a formation of edge thickening caused by neck-in during stretching of the pre-stretch film.
A device for producing pre-stretch film, the device comprising:
- a die defining a die outlet through which molten polymer is extruded, the polymer being suitable for producing the pre-stretch film;
- and
- at least one coolant supply positioned proximate the die outlet for directing a stream of coolant onto the polymer as the polymer exits the die outlet.
A method for producing pre-stretch film, the method comprising:
- providing a die having a die outlet and a film producing device spaced apart from the die outlet;
- providing a polymer suitable for producing the pre-stretch film;
- heating the polymer to a molten condition;
- delivering the polymer to the die;
- extruding the polymer through the die outlet towards the film producing device;
- directing a stream of coolant onto a first portion of the polymer at a position between the die outlet and the film producing device;
- and
- forming a film wherein the first portion of the polymer has a thickness that exceeds a base thickness of the film.
A pre-stretch film comprising:
- a layer of film comprising a material suitable for producing pre-stretch film, the film comprising a base thickness and a plurality of strips having a first thickness formed therein, wherein said strips run longitudinally along a length of the film and the first thickness is greater than a base thickness of the stretch film, wherein said strips are separated from each other.
A method for producing pre-stretch film, the method comprising:
- providing a film suitable for production of pre-stretch film, the film having strips of increased thickness;
- slitting the strips of increased thickness;
- and
- thinning out the film by stretching between stretching rollers rotated at different speeds, setting a spacing between the stretching rollers, the spacing being set to a magnitude to minimize neck-in between the stretching rollers thereby maximizing a width of the pre-stretch film and compensating for the reduction in natural edge thickening from the reduced neck-in by the added strip thickness.
A method for producing pre-stretch film, the method comprising:
- providing a film with strips of increased thickness, the film being suitable for production of pre-stretch film;
- slitting the strips of increased thickness;
- and
- thinning out the film by stretching between stretching rollers rotated at different speeds, selecting a diameter of the stretching rollers, the diameter being set to a magnitude to minimize neck-in between the stretching rollers thereby maximizing a width of the pre-stretch film and compensating for the reduction in natural edge thickening from the reduced neck-in by the added strip thickness.
A device for producing pre-stretch film, the device comprising:
- a die defining a die outlet through which molten polymer is extruded, the polymer being suitable for producing the pre-stretch film;
- the die defining a deformable die lip;
- an actuator in communication with the die lip for selectively deforming portions of the die lip to increase polymer flow through the deformations to produce strips of increased thickness exiting the die lip.
A device for producing pre-stretch film, the device comprising:
- a die defining a die outlet through which molten polymer is extruded, the polymer being suitable for producing the pre-stretch film;
- the die defining at least one die lip;
- at least one groove formed in the at least one die lip, the groove being configured to increase polymer flow through the at least one groove to produce strips of increased thickness exiting the die lip.
A device for producing pre-stretch film, the device comprising:
- a die having at least two sources of at least one molten polymer, the at least two sources being configured to output the at least one molten polymer at two or more different flow rates to produce strips of increased thickness exiting the die;
- and
- the polymer being suitable for producing the pre-stretch film.
A device for producing pre-stretch film, the device comprising:
- a die defining a die outlet through which molten polymer is extruded, the polymer being suitable for producing the pre-stretch film;
- the die defining a deformable die lip;
- at least one heat exchanger in communication with the die lip for selectively controlling polymer flow through the die lip to produce strips of increased thickness exiting the die lip.
Dependencies are inferred from the claim text.