E.i. Dupont De Nemours and Company

Isadore Swerlick

William D Garlington

Albert L Moore

Clare A Stewart

Film of a wholly aromatic polyamide, at least 85% of the repeating units of which are meta-phenylene isophthalamide units, which is undrawn and noncrystalline and which has improved impact strength. Such film is made by heat-treating film of the polyamide which is undrawn and noncrystalline at 400.degree. to 300.degree. C. for from 2 seconds to 2 minutes while maintaining the film at constant length and width permitting it to shrink by at most 20% in each of the length and width.

Casting films of polymers of meta-phenylene isophthalamide

Film of a wholly aromatic polyamide, at least 85% of the repeating units of which are meta-phenylene isophthalamide units, which is undrawn and noncrystalline and which has improved impact strength. Such film is made by heat-treating film of the polyamide which is undrawn and noncrystalline at 400.degree. to 300.degree. C. for from 2 seconds to 2 minutes while maintaining the film at constant length and width or while permitting it to shrink by at most 20% in each of the length and width.

Film of aromatic polyamide and process therefor

Terpolymer consisting of 12 to 48% by weight TFE units, 7 to 24% by weight HFP units and 30 to 81% by weight VF.sub.2 units, provided that when the content of TFE units is less than 42% by weight, the content of HFP units is less than 15% by weight. Heat-stable films such as polyimide film can be coated with a coating comprising the terpolymer to provide heat-sealable film useful as wire insulation.

Fluoropolymer hexafluoropropene, tetrafluorethene and 1,1-difluoroethene

Coated film having a base layer of an aromatic polymer such as polyimide, polyamide, polyamide-imide, or polyparabanic acid, and having on at least one side thereof a thermally stable, heat-sealable coating comprising a TFE:HFP:VF.sub.2 terpolymer of selected composition. The coated film is useful as wire insulation.

Coated, heat-sealable aromatic polymer film

An improvement in a process for preparing a high barrier, heat-sealable packaging material. A flexible base sheet carrying at least a one side copolymer high barrier coating applied from a solvent solution receives a second copolymer coating having optimum heat sealing properties from a dilute solvent coating system thereby yielding, when finally dried, a double copolymer distribution on the base sheet surface having a low level of total retained solvents, particularly high boiling point solvents.

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Wilmington, DE, United States of America

Isadore Swerlick