| 摘要 |
PROBLEM TO BE SOLVED: To provide a cleaning method capable of surely cleaning a polyester spinning line in a short time at a low cost and producing a polyester yarn free from a remaining admixture of a polymer of a former grade in a cleaning method using a cleaning polymer. SOLUTION: In a melt spinning process for remelting polymer chips of a polyester consisting essentially of a polyalkylene terephthalate by using the same spinning frame, when kinds of polymer of chips to be used are changed, this cleaning method comprises washing out a remaining polymer of a former grade by a cleaning polymer, the cleaning polymer consisting essentially of the polyalkylene terephthalate and satisfying the following equations is used for the washing. (1) 700<=ηm×√W<=3500, (2) 1000<=ηm<=3000 and (3) 0.1<=W<=2.0 with the proviso theηm is a melt viscosity (Poise) of the polymer at 280 deg.C and W is a concentration (wt.%) of titanium oxide in the polymer.
|
