False twist yarns and production method and production device therefor

A false twist yarn comprising (i) a synthetic fiber yarn, wherein the yarn has (ii) an elongation (EL) of not less than 20% and not more than 50%, (iii) a crimp rigidity (CR) of not less than 10% and not more than 40%, (iv) a crimp appearance stretch ratio (TR) of not less than 0.5% and not more than 15%, (v) a dry heat shrinkage stress maximum value (MCS) of not less than 0.1 cN/dtex and not more than 1.0 cN/dtex, (vi) a deformation degree of single filament (SDD) of not less than 1.0 and not more than 2.5, and (vii) an entanglement number (EN) of not less than 4 and not more than 50, wherein each of filaments forming not less than 30% of the yarn has a hollow percentage (HR) of 6% to 15%.

A false twist yarn comprising (i) a synthetic fiber yarn, wherein the yarn has (ii) an elongation (EL) of not less than 20% and not more than 50%, (iii) a crimp rigidity (CR) of not less than 10% and not more than 40%, (iv) a crimp appearance stretch ratio (TR) of not less than 0.5% and not more than 15%, (v) a dry heat shrinkage stress maximum value (MCS) of not less than 0.1 cN/dtex and not more than 1.0 cN/dtex, (vi) a deformation degree of single filament (SDD) of not less than 1.0 and not more than 2.5, and (vii) an entanglement number (EN) of not less than 4 and not more than 50, wherein the yarn comprises a mixture of filaments whose peripheral figure of cross section has no concave portion and whose peripheral figure of cross section has a concave portion, a deformation degree (SDD) of the filaments having no concave portion is 1.0 to 2.0, and a deformation degree (SDD) of the filaments having concave portion is 1.6 to 2.5.

A method for producing a false twist yarn comprising (i) an undrawn yarn feeding process that feeds an undrawn synthetic fiber yarn, (ii) a drawing and false twisting process that draws and false-twists the undrawn yarn fed from the undrawn yarn feeding process, and (iii) a false twist yarn winding process that winds up the false twist yarn produced by drawing and false twisting performed in the drawing and false twisting process, wherein (iv) the drawing and false twisting process contains a heater, a false twisting means, and a twist stopping means provided between the heater and the false twisting means, the undrawn yarn is heated by the heater while twisting motion imparted by the false twisting means on the undrawn yarn is restrained by the twist stopping means, and subsequently the heated drawn yarn, after passing through the twist stopping means, is false-twisted by the false twisting means with a starting point of twisting formed by the twist stopping means.

An apparatus for producing a false twist yarn comprising (i) an undrawn yarn feeding means that feeds undrawn synthetic fiber yarns, (ii) a drawing and false twisting means that draws and false twists the undrawn yarns fed from the undrawn yarn feeding means, and (iii) a false twist yarn winding means that winds up the false twist yarn produced by the drawing and false twisting performed by the drawing and false twisting means, wherein (iv) the drawing and false twisting means contains a heater, a false twisting means, and a twist stopping means provided between the heater and the false twisting means, the undrawn yarn is heated by the heater while twisting motion imparted by the false twisting means on the undrawn yarn is restrained by the twist stopping means, and subsequently the heated undrawn yarn, after passing through the twist stopping means, is false-twisted by the false twisting means with a starting point of twisting formed by the twist stopping means.