Patent ID: 8097048

Claim:
A method for producing a polyphenylene sulfide fiber containing a disperse dye and at least one ultraviolet absorber diffused into said polyphenylene sulfide fiber from the surface thereof, the polyphenylene sulfide fiber having a light-fastness rating of Class 1 or higher against light from an ultraviolet carbon arc lamp, which rating is measured in accordance with JIS L-0842, the method comprising the step of contacting a polyphenylene sulfide fiber with a processing liquid containing (a) said at least one ultraviolet absorber at a temperature between 100° C. and 130° C., said at least one ultraviolet absorber being selected from the group consisting of 2,4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and a compound represented by Formula (II) below: wherein R 6 is hydrogen or C 1 -C 5 linear or branched alkyl; R 7 is C 1 -C 5 linear or branched alkyl; and R 8 is hydrogen or chlorine; said processing liquid further comprising an agent for enhancing diffusion of the ultraviolet absorber into the polyphenylene sulfide member and containing at least one compound selected from the group consisting of a compound represented by Formula (III) below and a compound represented by Formula (IV) below, an emulsifier, (b) said disperse dye, and (c) a dispersing agent: wherein A is —O— or —C(O)O—; R 9 is phenyl or a derivative thereof, or substituted or non-substituted phenylalkylene; wherein R 10 is C 1 -C 5 aliphatic hydrocarbon; and X 1 and X 2 independently represent hydrogen or halogen.