Synthetic fiber capable of absorbing and disabsorbing moisture, entangled yarn blend using the same, knitted and woven goods using the same, and nonwoven fabric using the same

A synthetic fiber absorbing and disabsorbing moisture comprising a component absorbing and disabsorbing moisture and a fiber-forming polymer, wherein

• the component absorbing and disabsorbing moisture is a modified polyalkylene oxide obtained by a reaction of polyalkylene oxides, polyols, and aliphatic diisocyanate compounds, and
• the synthetic fiber absorbing and disabsorbing moisture has a moisture absorption of 1.5% or more when it is allowed to stand to reach a moisture equilibrium under the circumstance of 25° C.×60%RH and then is allowed to stand for 30 min. under the circumstance of 34° C.×90%RH, a moisture disabsorption of 2% or more when it is allowed to reach a moisture equilibrium under the circumstance of 25° C.×60%RH, and stand for 30 min. under the circumstance of 25° C.×60%RH, and a value of −1 to 5 in terms of b value in the CIE-LAB color system when it is allowed to stand for 30 days.