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US 5,759,462 AGranted
Electrically conductive tapes and process
AssigneeAmoco Corporation
InventorErich Gebhard Jordan
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Abstract
Electrically conductive tape yarns of two or more layers comprising thermoplastic polymer resin and electrically conductive particles are prepared by a process comprising extruding a multilayer film containing at least one electrically conductive layer and at least one layer substantially free of electrically conductive particles, quenching the film, slitting the film into tapes and orienting the film before or after slitting.
Claims10
A process for forming electrically conductive tape comprising the steps of
- (a) coextruding a molten, multi-layer film comprising at least one electrically conductive layer comprising a first thermoplastic resin composition comprising a propylene polymer having a melt flow rate of about 2 to about 5 grams per 10 minutes having dispersed therein an amount of electrically conductive particles effective to impart electrical conductivity to the tape and at least one layer of a second thermoplastic resin composition comprising a propylene polymer having a melt flow rate of about 3 to about 8 grams per 10 minutes, and being at least substantially free of conductive particles wherein such melt flow rates are determined according to ASTM D-1238 at 230.degree. C. under load of 2.16 kg and the ratio of melt flow rate of the first thermoplastic resin composition to melt flow rate of the second thermoplastic resin composition is about 0.1:1 to about 0.5:1;
- (b) drawing down the molten film to stabilize the same for downstream processing without formation of gaps or thin spots in the molten film;
- (c) cooling the stabilized, molten film to solidify the resin compositions constituting the same;
- (d) slitting the film along its length;
- and
- (e) orienting the film in at least the lengthwise direction.
3 more elements
Dependencies are inferred from the claim text.