To obtain heat adhesive fiber having a good fatigue resistance at high temperatures and suitable for cushion materials by using a specific polymer at least in a part and adhering a specific oil solution.
This heat adhering fiber having ≤200°C melting point is formed by comprising, e.g. a core-sheath type conjugate fiber using a polymer satisfying the following relations: 75≤Tg≤150 and 0≤Tm-Tg≤80, where Tg is the glass transition temperature and Tm is the melting point of the polymer and has ≤1000 g, preferably ≤500 g adhesive strength after 22 hours retention in 70°C dry heat and adhering an oil solution containing 30-50 wt.% of the potassium salt of an alkyl phosphate ester having an 8-16C saturated hydrocarbon group and 30-50 wt.% of a fatty acid diester of a polyethylene glycol comprising an 8-16C saturated fatty acid and a polyoxyethylene having 200-1000 molecular weight to the fiber. A cushion material having ≥70% fatigue resistance at 70°C is obtained by using the above mentioned heat adhering fiber at least in a part and integrating to have one structure by heat forming the fiber.
SUGIMURA SHOICHI
KONNO YOSHIHIRO
