Japanese Examined Patent Publication (Kokoku) No. 43-19108, Japanese Unexamined Patent Publication (Kokai) Nos. 11-189923, 2000-239927 and 2000-256918 disclose a composite fiber spinning technique in which the polytrimethylene terephthalate is used as a first component, and a polyester such as another polytrimethylene terephthalate, polyethylene terephthalate or polybutylene terephthalate or nylon