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US 8,075,830 B2Granted
Polypropylene blown film
AssigneeFina Technology, Inc.
InventorsRodolfo Mier, Mark Miller, Raleigh McBride
Life of this patent
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Abstract
A blown film that comprises polypropylene that has a melt flow rate of 1.8 to 14.0 g/10 min. and a melting point of at least 115° C. The blown film has a haze of less than 10% and a gloss of greater than 70%. The blown film may be co-extruded with a medium density polyethylene or 15 wt % of an impact copolymer. A clarifier may also be incorporated. The blown film that comprises polypropylene is produced on a standard air cooled blown film line.
Claims12
A process of forming a blown film comprising:
- providing a Ziegler-Natta catalyzed polypropylene having a melt flow rate of from 1.8 to 14.0 g/10 min. as measured by ASTM D1238 condition L and a melting point of at least 115° C.;
- and
- forming the polypropylene into a layer of a blown film, wherein the layer consists of the polypropylene;
- and
- quenching said blown film with air at a temperature of less than 10° C., wherein said blown film has a haze of less than 10% as measured in accordance with ASTM 1003 and a 45° gloss of greater than 70% as measured in accordance with ASTM D523, and wherein said process further comprises internal bubble cooling, stabilizing the external bubble with stabilizers, and the process utilizes a dual lip air ring, and wherein the blown film exhibits a 1% secant modulus (machine direction) measured in accordance with ASTM D882 in the range of 80 to 135 kpsi when the blown film has a thickness of 1.2 mil.
2 more elements
Dependencies are inferred from the claim text.