Abstract:

In order to study the effect of fiber mechanical properties on twisting degree of self twist yarn, and the relationship between the twist angle and fiber bending stiffness, torsional stiffness is derived from the conservation of total strain energy during the process of self-twist spinning. The formula shows that the larger bending stiffness has the smaller twist angle and the bigger torsional stiffness has the larger twist angle. So the size of the twist angle is proportional to the radio of fiber torsional stiffness and bending stiffness, namely with the ratio of fiber torsional stiffness and bending stiffness raises, twist angle increases, and the number of the self-twist twists is greater. By testing the number of the self-twist yarn twists respectively spun from ramie, polyester, acrylic and wool, the above relationship is verified and the conclusion can be drawn as: wool and acrylic are more suitable for self-twist yarn by self-twist spinning with greater self-twist number, but polyester and ramie are not suitable for textile developmtent by self-twist spinning with smaller self-twists number.

Key words: self-twist, titak straub energy, tist angle, bending stiffness, torsional stiffness