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AssigneeToray Industries, Inc.
InventorsIsoo Saito, Takuji Sato, Koichi Kubota, Masaharu Yamamoto
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A conjugated fiber having a sheath-core conjugated structure comprising a polyester core component composed mainly of polyethylene terephthalate and a polyamide sheath component composed mainly of polyhexamethylene adipamide, is disclosed, which has excellent mechanical properties such as a high tenacity, a high modulus, and an improved dimensional stability, and an improved adhesion to a rubber, especially a high-temperature adhesion, an improved heat resistance in a rubber, and a high fatigue resistance, and thus is useful as an industrial material. By adopting a high-speed spinning procedure in the fiber preparing process, the peel resistance in the interface of the sheath-core conjugated structure is greatly improved, and the following valuable characteristics not possessed by conventional conjugated yarns can be obtained: (1) Excellent adhesion and high-temperature adhesion comparable to those of a polyamide, which cannot be obtained in a polyester. (2) High modulus and dimensional stability comparable to those of a polyester, which cannot be obtained in a polyamide. (3) A heat resistance in a rubber and a fatigue resistance superior to those of a polyester.
A high-tenacity conjugated fiber having a sheath-core conjugated structure consisting essentially of a polyester composed mainly of ethylene terephthalate units as the core component and a polyamide as the sheath component, wherein the ratio of the core component to the sum of the core component and sheath component is 30 to 90% by weight, and the conjugated fiber has (a) a hynamic elasticity (E'.sub.20) at 20.degree. C. of at least 8.times.10.sup.4 dyne/denier and a dynamic elasticity (E'.sub.150) at 150.degree. C. of at least 3.times.10.sup.4 dyne/denier, as measured at 110 Hz, and a main dispersion peak temperature (T.alpha.) of at least 140.degree. C. in the mechanical loss tangent (tan .delta.) curve, (b) a creep rate (CR.sub.20) not larger than 2.0% as measured at 20.degree. C. after 48 hours' standing under a load of 1 g/denier and a creep rate (CR.sub.150) not larger than 3.0% as measured at 150.degree. C. after 48 hours' standing under a load of 1 g/denier, (c) an intrinsic viscosity ([.eta.]) of at least 0.8 and a birefringence (.DELTA.n) of 160.times.10.sup.-3 to 190.times.10.sup.-3 in the polyester core component, (d) a sulfuric acid relative viscosity (.eta.r) of at least 2.8 and a birefringence (.DELTA.n) of at least 50.times.10.sup.-3 in the polyamide sheath component, (e) a tenacity (T/D) of at least 7.5 g denier, (f) an initial modulus in tension (Mi) of at least 60 g/denier, and (g) a dry heat shrinkage (.DELTA.S.sub.150) as measured at 150.degree. C. of not larger than 7%.
Dependencies are inferred from the claim text.