| 摘要 |
PURPOSE:To provide a machine sewing thread excellent in heat resistance without causing yarn breakage and fluff, by melt spinning a linear polyether ether ketone of a specific structure, drawing and heat-treating the resultant yarn, primarily twisting the obtained yarn at a specific twist coefficient, setting twists, finally twisting the yarn and setting the twists. CONSTITUTION:A polymer having recurring units consisting of >=85% linear polyether ether ketone expressed by formula I is melted, spun at 360-390 deg.C spinneret temperature, drawn and heat-treated to provide a drawn yarn, which is then subjected to primary twist so as to afford 3000-12000 twist coefficient (K) expressed by formula II (T is the number of twists; DC is denier of the multifilament yarn) and twist setting at >=160 deg.C. The plural obtained yarns are then doubled and subjected to final twist so as to provide 3000-15000 twist coefficient (K) and subsequently twist setting at >=180 deg.C so as to afford <=20T/m untwisting torque (T). Thereby, the aimed machine sewing thread having >=4.5 g/de strength (St) expressed by formula III (El is elongation), >=20 silk factor (SF) and <=8.0% dry heat shrinkage factor (HS) at 220 deg.C is obtained. |
