Rhone-poulenc Fibres

Paul Antikow

Francois Pinaud

Undrawn preoriented polyester yarns containing 0.03 to 0.01% of fumed silica with a particle size of between 5 and 15 nm, exhibit a delay in crystallization.

Undrawn pre-oriented pet yarns with improved production efficiency

Process for improving the production efficiency of the spinning of an undrawn, preoriented yarn based on polyethylene terephthalate (PET) by the introduction, before the spinning, of 0.03 to 0.1% by weight of fumed silica with a particle size of between 5 and 15 nm into the molten polymer in the form of dispersion in a masterbatch of the same polymer as that to be processed, then spinning the PET containing the silica in the finely dispersed state, the filaments being next cooled by means of a gas stream at temperature between 17.degree. to 22.degree. C. and then sized and wound at a velocity of between 3500 and 5000 m/min. The gain in production efficiency, evaluated in relation to the shrinkage of the filaments in dry air at 180.degree. C., is at least 7%, generally at least 10-15%.

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Lyons, France

Paul Antikow