Abstract: The present invention provides an improvement in a process for providing a dyed, false twist texturized, fibrous material comprising at least 85 mole percent polyethylene terephthalate which is subject to variations in dye uptake induced by the false twist texturizing treatment conducted on said fibrous material prior to or concurrently with a dyeing process by enhancing the uniformity of dye uptake of the fibrous material. The enhancement in the uniformity of dye uptake is achieved by subjecting the fibrous material, which has been previously oriented but prior to false twist texturizing, to an annealing step at a specifically defined temperature for a specifically defined length of time while controlling the length of the fibrous material in a specifically defined manner.

Abstract: An improved polyester filament (i.e., a principally polyethylene terephthalate filament) suitable for use in commercial applications is provided having a unique internal structure. The filament possesses an interconnected highly oriented crystalline microstructure coextensive with its length coexisting with an interdispersed substantially disoriented non-crystalline phase. The filament microstructure imparts inter alia a propensity for the filament to undergo a low degree of shrinkage under a high degree of force at an elevated temperature as evidenced by a modulus ratio (as defined) of at least 0.1. The filament exhibits a relatively high initial modulus, coupled with a relatively high crystalline orientation function, and a relatively low amorphous orientation function.

Abstract: An improved process is provided for the formation of a high performance polyester (at least 85 mol percent polyethylene terephthalate) multifilament yarn. The product possesses a high strength (at least 7.5 grams per denier) and an unusually stable internal structure which renders it particularly suited for use in industrial applications at elevated temperatures. The filaments are melt spun and uniformly quenched under relatively high stress conditions (as described) to yield an as-spun filamentary material of relatively high birefringence (+9.times.10.sup.-3 to +70.times.10.sup.-3) which is passed in-line from the quench zone to a first draw zone where it is drawn at a draw ratio of 1.01:1 to 3.0:1, and subsequently is drawn (as described) to achieve at least 85 percent of the maximum draw ratio of the as-spun filamentary material. The resulting filamentary material exhibits unusually low shrinkage and hysteresis characteristics (i.e. work loss characteristics) as well as the high strength chatracteristics.

Abstract: An improved high performance polyester (at least 85 mol percent polyethylene terephthalate) multifilament yarn possessing a novel internal structure is provided. The multifilament yarn of the present invention possesses a high strength (at least 7.5 grams per denier) and an unusually stable internal structure which renders it particularly suited for use in industrial applications at elevated temperatures. As described in detail hereafter the subject multifilamentary material exhibits unusually low shrinkage and hysteresis characteristics (i.e. work loss characteristics) coupled with the high strength characteristics normally associated with polyester industrial yarns. Accordingly, when utilized in the formation of a tire cord and embedded in a rubber matrix, a highly stable tire may be formed which exhibits a significantly lesser heat generation uon flexing.

Abstract: A wholly aromatic polyester is provided which has been found to be highly amenable to melt extrusion to yield high performance fibers. Such fibers following thermal treatment exhibit high tenacity and tensile modulus properties which are well retained at elevated temperatures while exhibiting a low degree of shrinkage. Unlike wholly aromatic polyesters normally encountered in the prior art, the polymer of the present invention is not intractable and may be melt extruded with ease at temperatures below approximately 300.degree. C., and preferably below approximately 280.degree. C. The aromatic polyester of the present invention consists essentially of recurring units (a) p-oxybenzoyl moiety, (b) 2,6-dicarboxynaphthalene moiety, (c) symmetrical dioxy aryl moiety (as defined), and (d) isophthaloyl moiety and/or metal-dioxy phenylene moiety, and is free of units which possess ring substitution.

Abstract: An improved process is provided for the production of polymeric filamentary material or film. Molten melt-spinnable polymeric material capable of undergoing crystallization (e.g., a polyester) is extruded through a shaped orifice to form a filamentary material or film under high stress conditions, quenched to below its glass transition temperature to form a solid filamentary material or film, and sequentially passed for a brief residence time through a thermal conditioning zone at a temperature between its glass transition temperature and its melting temperature wherein the internal structure thereof is modified and substantial crystallization of the previously solidified filamentary material or film takes place. The filamentary material or film is withdrawn from the conditioning zone at a rate of 1000 to 6000 meters per minute while under a relatively high stress of about 0.1 to 1.0 gram per denier.