MECHANICAL BEHAVIOR OF CRIMPED SYNTHETIC YARN

The stress recovery of the crimped yarn after the constant elongation for hours was investigated.Parameters taken into consideration are t1 (time required to arrive at constant elongation), ts (during which time elongation is kept at initial length), and tt (during which time elongation is kept at constant elongation).The resluts are as follows.It is apparent that recovery coefficient is lowered with increase of rate of elongation. The rate of elongation in this experiment is lower as compared with that of the ordinary. But recovery coefficient is also lowered with high increase in the rate of elongation in the case of felse-twist method yarn. Then it may be deduced that the recovery coefficient decreases with the rate of elongation.As a quantity of constant elongation is increased. ts the time required to recover initial state is increased. But in conventional-twist method yarn, recovery coefficient is small at lower elongation, because force of crimp friction is larger at lower elongaton in the yarn.Conventional-twist method yarn has a special property in water, because of due to the characteristic condition of heat treatment and shape of crimps.