Modified regenerated cellulose fiber and fiber product thereof

A method for dyeing regenerated cellulose fiber comprising the steps of:

• adding and mixing 0.5–3.0% by weight of a grounding agent of naphthol dye to the regenerated cellulose fiber into a polynosic viscose solution;
• said weight of grounding agent of naphthol dye based on the weight of cellulose in the polynosic viscose solution;
• said grounding agent of naphthol dye being selected from the group having a medium to high level affinity to the regenerated cellulose fiber;
• extruding the polynosic viscose solution into a spinning bath to produce a modified regenerated cellulose fiber containing the grounder of naphthol dye therein;
• mixing or knitting/weaving the modified regenerated cellulose fiber with other cellulose-based fiber;
• dyeing the mixture of the cellulose fibers by using a diazo component as a developer of naphthol dye;
• and
• further dyeing the products by a reactive dye.

A method for producing mélange yarns comprising the steps of:

• adding and mixing 0.5–3.0% by weight of a grounding agent of naphthol dye into a polynosic viscose solution;
• said weight of grounding agent based on the weight of cellulose in the polynosic viscose solution;
• said grounding agent of naphthol dye being selected from the group having a medium to high level of affinity to the regenerated cellulose fiber;
• extruding the polynosic viscose solution into a spinning bath to produce a modified regenerated cellulose fiber containing the grounder of naphthol dye therein;
• mixing the modified regenerated cellulose fiber containing a grounder of naphthol dye with other cellulose-based fiber;
• and then
• dyeing the cellulose fibers by using a diazo component as a developer of naphthol dye to obtain mélange yarns.