Stabilized polypropylene fibers pigmented with red 144

Abstract

Excellent stabilization to bright sunlight, is obtained in polypropylene (PP) fibers pigmented with Red 144, by combining the pigment with N-(substituted)-1-(piperazin-2-one alkyl)-.alpha.-(3,5-dialkyl-4-hydroxyphenyl)-.alpha.,.alpha.-substituted acetamide ('3,5-DHPZNA' for brevity). Stabilization of the red color is obtained for as long as the PP fibers themselves are stabilized by the 3,5-DHPZNA. 3,5-DHPZNA is a known hybrid stabilizer having a hindered amine N-(substituted)-1-(piperazin-2-one alkyl) group at one end, and a hinderd phenol (3,5-dialkyl-4-hydroxyphenyl) group at the other. This particular hybrid, containing a piperazinone group, combined through a disubstituted alpha carbon atom of the acetamide in a single molecule, affords the advantages of each group with respect to its stabilization of the fiber against degradation, but without the expected adverse interaction of each group with Red 144 pigment. With 3,5-DHPZNA and Red 144 pigment, essentially no secondary stabilizer is necessary. Red PP fibers so stabilized, exhibit an acceptably low level of discoloration (color faidng) due to degradation of the pigment, over the useful life of the PP fibers. When exposed to sunlight for 6 months in Florida at a 45.degree. South exposure, the red PP fibers suffer essentially no loss of color due to degradation of the pigment. Retention of red color in articles exposed to sunlight over their useful life, is of great practical value in clothing and household goods made from woven or non-woven fabrics of Red 144-pigmented PP fibers.