PREPARATION OF ELASTOMER FIBER

PURPOSE: To provide a process for preparing polyurethane elastic fibers which maintain physical properties specific to elastic fibers and also which are superior in thermal resistance and chlorine resistance. CONSTITUTION: Diol compounds consisting of a high molecular diol compd. having a number average molecular weight of 1,000-3,000, preferably 1,500-2,500, and a low molecular diol compd. of the formula I (R1 and R2 are each phenyl, 1-20C alkyl or alkylaryl) having a number average molecular weight of 50-500 are pre-polymerized with a diisocyanate compd., and then a solvent is mixed thereto, to prepare a soln. of the pre-polymer. Then, the pre-polymer is subjected to chain propagation by means of a diamine comp. to obtain viscosity useful for spinning, and thereafter subjected to chain stopping by means of a monoamine compd., to which a metal compd. of the formula II (R3 is CH2 -CH2 or phenyl, R4 is 1-10C alkyl, 5-15C aryl or alkylaryl; M1 and M2 are each Na, Ca, Al, Zn, Ba or Pb; n is 1-20) that is a chlorine resistance improving agent and a phosphorus type compd. that is a light-fastness improving agent are added to obtain the polymer. It is then spun.