BULK DYEING OF PLASTIC

PROBLEM TO BE SOLVED: To carry out a bulk dyeing of a thermoplastic resin into a yellow dyed molding good in color fastness by using a specific dyestuff. SOLUTION: A dyestuff of the formula [n is 1 or 2; R0 is an aryl, a heteroaryl or a heterocyclylidenemethyl for n=1 or R0 is a direct bond or an arylene for n=2; the ring A is unsubstituted or substituted by a 1-4C alkyl, a 5-8C cycloalkyl, a 6-10 aryl, a 1-4C alkyloxy, a 6-10C aryloxy, a 6-10C aryl or a 1-4C alkylsulfonyl, cyano, a halogen or a radical of the formula COR1 (R1 is a 1-4C alkoxy, amino, a 1-4C alkylamino, a 6-10C arylamino, a 1-4C alkyl or a 6-10C aryl or contains a fused-on aromatic or a cycloaliphatic ring)] is finely divided, mixed with plastic particles and homogenized. The resultant mixture is then subjected to spinning into, e.g. bristles or filaments or by extrusion or injection molded to afford a greenish yellow to a violet dyed molding excellent in light and weather resistance.