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US 4,604,324 AGranted
Multi-layer polypropylene film structure and method of forming the same
AssigneeMobil Oil Corporation
InventorsA. Michael Nahmias, Hee C. Park
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Abstract
A multi-layer polypropylene structure of low COF also having antistick characteristics over a wide temperature range and a method of forming the same.
Claims15
An oriented multi-layer polypropylene film structure comprising coextruded layers of:
- (a) a base layer comprising polypropylene of comparatively high stereoregularity;
- and
- (b) a skin layer comprising a polyolefin of comparatively low stereoregularity on at least one surface of (a), said skin layer containing a combination of finely divided silica, a silicon oil and a polymer incompatible with said skin layer polyolefin, said incompatible polymer having a melting point of greater than 150.degree. F. above the melting point of the skin layer polyolefin.
The process for preparing an oriented multi-layer polypropylene structure comprising melt coextruding a combination of:
- (a) a base layer comprising polypropylene of comparatively high stereoregularity;
- and
- (b) a skin layer comprising a polyolefin of comparatively low stereoregularity selected from the group consisting of an ethylene-propylene copolymer and an ethylene-propylene-butylene terpolymer;
- on at least one surface of (a), said skin layer containing a combination of finely divided silica and a silicon oil;
- and also containing a polymer incompatible with said skin layer polymer, said incompatible polymer having a melting point of greater than about 150.degree. F. above the melting point of said skin layer polymer;
- and orienting the structure.
3 more elements
Dependencies are inferred from the claim text.