| 摘要 |
PROBLEM TO BE SOLVED: To obtain a latently crimpable polyester-based conjugate yarn having both-stabilized operability and excellent crimp developing properties by selecting a polyethylene terephthalate(PET) having a proper melt viscosity for a spinning temperature and a polybutylene terephthalate(PBT) having a proper difference in melt viscosity from the PET. SOLUTION: This latently highly crimpable polyester conjugate yarn has a difference in melt viscosity [Ya-b between the PBT the component and the PET component at a temperature (X) within the range of 260-290 deg.C satifying the following formula (a), further the melt viscosity [Yb] of the PET component satisfying the following formula (b) and the two components conjugated into a side-by-side type in (35:65) to (65:35) ratio. The conjugate yarn has >=17% crimp extension percentage when subjected to a boiling water treatment. (a) -2.72X+993<=[Ya-b]<=-16.1X+5,900 and (b) -10.8X+3,360<=[Yb]<=-33.3X+12,300 [Ya-b] is the difference in melt viscosity (poises) between the PBT and the PET; [Yb] is the melt viscosity (poises) of the PET}.
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