Abstract: The process for production of a heat-stable and light-fast product consisting of multifilaments, monofilaments or flock for textile and industrial applications includes mixing from 0.2 to 0.5% by weight, based on the amount of product, of a UV absorber having a melting point of from 135 to 145° C. and a colorant having a melting point greater than 180° C. with a polyester powder at room temperature to form a starting mixture; feeding from 1 to 100% of the starting mixture and from 0 to 99% by weight PET granules into a cooled feed zone of a twin-screw extruder; operating the twin-screw extruder to melt, knead and homogenize the feed to form polymer strands, which are then cooled and cut to form a compound; and subsequently melt-spinning the compound to form the product. When the product is made by this method the UV absorber is incorporated in the product, thus avoiding the additive-related manufacturing problems.

Abstract: Process for making a polyester having polyethylene terephthalate units including transesterifying a terephthalic acid ester with a glycol using a manganese salt as catalyst and then subjecting the product to a polycondensation reaction using a germanium-containing catalyst to form a polyester; adding phosphorous compounds to block 80 to 99% by weight of the active manganese salt thus leaving an unblocked portion of the manganese salt prior to the polycondensation; and adding 10 to 100 ppm of Ge at the end of a ethylene glycol stage of the polymerization so that the Ge and the unblocked portion of the manganese salts provide the germanium-containing catalyst for the polycondensation reaction. The P/Mn molar ratio being less than 1. The reaction mixture contains 10 to 100 ppm of manganese during the reaction.

Abstract: The process for making a polyamide filament having thermal and mechanical properties close to those of nylon 66 but without spherulites includes concentrating an aqueous solution of adipic acid-hexamethylenediamine salt containing from 1 to 10% by weight of .epsilon.-caprolactam and from 1 to 15% by weight of PA 6.HHT to form a condensed mixture; polycondensing the condensed mixture to form a polycondensed mass; and melt-spinning the polycondensed mass to form the polyamide filament. The process parameters are controlled to produce a polyamide filament consisting essentially of at least 80% by weight nylon 66 monomer, 1 to 10% by weight nylon 6 monomer and 1 to 15% by weight PA 6.HHT.