| abstract |
(57) [Abstract] [Purpose] To provide a synthetic fiber which has both vibration damping performance and stretchability without sticking in fiberization. [Structure] A styrene block (A) having a number average molecular weight of 2500 to 40,000, a number average molecular weight of 10,000 to 200,000, a content of 3,4 bonds and a content of 1,2 bonds of 40% or more and a temperature of 0 ° C or more. a triblock copolymer having a number average molecular weight of 30,000 to 300,000 and a polyolefin composed of an isoprene block (B) having a main dispersion peak of an δ, and The melt viscosity of the block copolymer at 280 ° C. is 280 poise or more higher than the melt viscosity of the polyolefin, and A composite fiber in which 50% or more of the circumference of the fiber cross section is occupied by polyolefin. |