MANUFACTURING METHOD OF A POLYURETHANE ELASTIC FIBER WITH IMPROVED HEAT SETTING PROPERTY

摘要

A manufacturing method of a polyurethane elastic yarn with the enhanced heat setting property is provided to mix and use two or more polytetra methylene glycols with different molecular weight and to mix and use the diamine as a chain extension agent. A polyol and an excess diisocyanate are polymerized firstly and then the reserve polymer is obtained. The reserve polymer is melted at the organic solvent so that a solution is obtained. Thereafter, the chain extension agent is added into the obtained solution and then the polymerization is performed secondly so that a polyurethane elastic yarn is manufactured. At least two or more kinds of polytetramethylenether glycols with different molecular weight are mixed and used as the polyol. At least one kind of polytetramethylenether glycol is the molecular weight of above 3000. The polytetramethylenether glycol with the molecular weight of above 3000 is contained as much as about 5 mol% to 70 mol% compared to the other polytetramethylenether glycols.