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AssigneeRhone-Poulenc Fibres
InventorsDenis Jehl, Bernard Millaud, Jean Staron
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The present invention relates to a process for obtaining continuously polyethylene terephthalate modified by --SiO-- groups in a proportion of 30014 700 ppm of Si during the direct esterification reaction between terephthalic acid and ethylene glycol, followed by polycondensation in a known manner by introducing methoxyethyl silicate or propyl silicate at a time when the prepolymer has a weight-average molecular mass of between 9,000 and 16,000, a polydispersity index of between 1.5 and 2, and when it is at a temperature of between 260.degree. and 290.degree. C., and at a pressure of between 1.5 and 2.5 bars, the silicate/prepolymer reaction time being at least 5 minutes. The present invention also relates to pilling-free fibers originating from the modified polyethylene terephthalate and to a process for obtaining them.
A process for producing a silicon containing polyethylene terephthalate comprising forming a prepolymer by direct esterification between ethylene glycol and terephthalic acid to produce a prepolymer having a weight average molecular mass Mw between 9,000 and 16,000 and a polydispersity index between 1.5 and 2, continuously introducing methoy ethyl or propyl silicate into the prepolymer at a temperature between 260.degree. and 290.degree. C. and at a pressure between 1.5 and 2.5 bars, subsequently reacting the silicate/prepolymer mixture and polycondensing the prepolymer to produce polyethylene terephthalate wherein the silicate/prepolymer mixture reaction time is at least 5 minutes.
Dependencies are inferred from the claim text.