Method to improve properties of poly (Trimethylene terephthalate) film
AssigneeE. I. Du Pont de Nemours and Company
InventorDonna Lynn Visioli
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Abstract
The invention herein provides a method to improve retention of tensile properties upon aging in poly(trimethylene terephthalate) cast film. The method involves first nucleating the poly(trimethylene terephthalate) resin prior to film formation and controlling the quench temperature during casting of the film. The quench temperature should be controlled to a temperature in the range of from about 10° C. below the Tg of the poly(trimethylene terephthalate) to about 15° C. above the Tg of the poly(trimethylene terephthalate).
Claims14
A method to improve the retention of tensile properties upon aging in 3GT cast film comprising the steps of:
- (a) prior to film formation, nucleating 3GT resin by adding the mono-sodium salt of a dicarboxylic acid selected from the group consisting of monosodium terephthalate, monosodium napthalene dicarboxylate and monosodium isophthalate as a nucleating agent during the synthesis of the 3GT resin;
- (b) casting the nucleated 3GT resin into a film;
- and
- (c) controlling the quench temperature during casting of the film to a temperature in the range of about 10° C. below the Tg of the nucleated 3GT resin to about 150° C. above the Tg of the nucleated 3GT resin.
A method to improve the retention of tensile properties upon aging in 3GT cast film comprising the steps of:
- (a) prior to film formation, nucleating 3GT resin in situ by adding an appropriate sodium containing species to a polymerization reaction mixture comprising a dicarboxylic acid;
- (b) casting the nucleated 3GT resin into a film;
- and
- (c) controlling the quench temperature of the film during casting to a temperature in the range of about 10° C. below the Tg of the nucleated 3GT resin to about 15° C. above the Tg of the nucleated 3GT resin.
A method to produce improved 3GT cast film comprising the steps of:
- (a) polymerizing a mixture of trimethylene glycol and terephthalic acid;
- (b) adding a nucleating agent comprising the mono-sodium salt of a dicarboxylic acid selected from the group consisting of monosodium terephthalate, monosodium napthalene dicarboxylate and monosodium isophthalate, to the mixture of step (a);
- and
- (c) casting a film from the polymerized mixture while controlling the quench temperature of the film to a temperature in the range of about 10° C. below the Tg of the polymerized mixture to about 15° C. above the Tg of the nucleated 3GT resin.
Dependencies are inferred from the claim text.