Polypropylene films
AssigneeExxonMobil Chemical Patents Inc.
InventorsJeffrey Wen-Cheng Kuo, Kenneth Lewtas, William Moa-Tseng Chien
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Abstract
Films disclosed herein contain a base or core layer comprising a first polypropylene, a second polypropylene, and a hydrocarbon resin. The base layers may also include other additives as described below. The first polypropylene is preferably a high crystallinity polypropylene having a melting point above about 155° C. or a polypropylene having a polydispersity (Mw/Mn) greater than about 4.0. The second polypropylene may be any conventional polypropylene, preferably having a melting point below about 160° C. and/or a polydispersity less than about 5.0.
Claims4
A film containing a layer comprising:
- (a) about 2-50 wt % of a polypropylene selected from:
- (i) polypropylene having a melting point greater than about 155° C.;
- (ii) polypropylene having a polydispersity greater than about 4;
- (iii) polypropylene having greater than about 96% heptane insolubles;
- (iv) polypropylene meeting two or more (i)-(iii);
- and
- (v) combinations of two or more of (i)-(iv).
- (b) about 2-50 wt % of a hydrocarbon resin;
- (c) less than about 96 wt % of a polypropylene having a melting point below 160° C.;
- and
- (d) optionally, about 0.05-40 wt % of one or more additives.
A masterbatch for use in making a film comprising about 10-90 wt % hydrocarbon resin and about 10-90 wt % polypropylene selected from:
- (a) polypropylene having a melting point greater than about 155° C.;
- (b) polypropylene having a polydispersity greater than about 4;
- (c) polypropylene having greater than about 96% heptane insolubles;
- (d) polypropylene meeting two or more (a)-(c);
- and
- (e) combinations of two or more of (a)-(d).
A process for the production of oriented polypropylene films comprising blending a polypropylene having a melting point greater than about 155° C. and a hydrocarbon resin to form a masterbatch containing from 10 to 90 wt % of the resin and subsequently blending the masterbatch with additional polypropylene and extruding the resultant blend to form a film, wherein the polypropylene in the masterbatch is selected from:
- (a) polypropylene having a melting point greater than about 155° C.;
- (b) polypropylene having a polydispersity greater than about 4;
- (c) polypropylene having greater than about 96% heptane insolubles;
- (d) polypropylene meeting two or more (a)-(c);
- and
- (e) combinations of two or more of (a)-(d).
Dependencies are inferred from the claim text.