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US 2019/0329472 A1Published application
Plant comprising a twin-screw extruder for the continuous production of rolls of plastic stretch film
OwnerMaurizio Mencarelliinventor
Life of this patent
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Abstract
A twin-screw extruder is configured to produce rolls of plastic stretch film on a continuous basis, starting from the extrusion of granules of one or more polymers an using cast extrusion.
Claims9
A plant (100) for continuous production of rolls of plastic stretch film (50) starting from granules of one or more polymeric plastic materials, said plant comprising:
- an extrusion unit (80) that is a cast extrusion unit, in monoextrusion or in coextrusion, and that comprises a flat extrusion die (6) and one or more extruders (2,3) positioned upstream of said flat extrusion die (6), to form a melt of said one or more polymeric plastic materials;
- a solidification unit of said melt comprising at least one chill-roll (7) with a continuous surface, positioned immediately downstream of said flat extrusion die (6) so as to solidify said melt, by cooling, to obtain said plastic stretch film (50);
- and
- one or more winding units of the plastic stretch film into rolls, adapted to discharge said rolls after said rolls are produced,
- wherein at least one of the extruders (2,3) of said one or more polymeric plastic materials is a twin-screw extruder (2), and
- wherein said twin-screw extruder (2) supplies a respective amount of the melt of the one or more polymeric plastic materials with a pressure, at an outlet mouth, so as to fill parts of said plant positioned immediately downstream of said twin-screw extruder (2).
3 more elements
A process for continuous production of rolls of plastic stretch film (50) starting from extrusion of granules of one or more polymeric plastic materials, said process comprising:
- extruding by cast extrusion said stretch film (50) through a flat extrusion die (6) fed by one or more extruders (2,3) of said granules, wherein at least one of the extruders (2,3) is a twin-screw extruder (2) which supplies the one or more polymeric plastic materials in molten state, with a pressure, at an outlet mouth, which is such as to fill parts of equipment positioned immediately downstream of said twin-screw extruder (2);
- cooling and solidifying said molten plastic film with at least one chill-roll (7) so as to obtain a solidified plastic stretch film (50);
- optionally, controlling a thickness of the solidified stretch film (50) to keep said thickness constant with respect to a width of the stretch film (50);
- and
- optionally, treating the stretch film (50) by oscillation, in order to improve an aesthetical appearance of the rolls of the plastic stretch film (50).
2 more elements
(canceled)
Dependencies are inferred from the claim text.