Composite yarn

摘要

To provide a fiber having a good temperature control function both at time of temperature rise and at time of temperature fall.SOLUTION: A synthetic fiber comprises a thermoplastic resin containing a component 1 and a component 2. The component 1 has a melting start temperature of 34°C or higher and a melting peak temperature of 50°C or lower. The component 2 has a crystallization start temperature of lower than 30°C and a crystallization peak temperature of 5°C or higher. In particular, a synthetic fiber preferably has: a melting heat value ΔHm of the component 1 of 10 to 150 J/g ; a crystallization heat value ΔHc of the component 2 of 10 to 150 J/g; a melting heat value ΔHm of synthetic fiber observed at 50°C or lower of 1 to 5 J/g; and a crystallization heat value ΔHc of 1 to 5 J/g observed at 50°C or lower.SELECTED DRAWING: None