Dye suitable for use in dyeing of cotton yarn for denim, dyeing process of cotton yarn cordao for denim, yarn dyed denim and the dyes

摘要

A dye suitable for use in dyeing denim cotton yarns comprises at least one quinophthalone derivative represented by the following general formula (I) or (II): CHEM wherein X means H, Br or Cl and Y denotes H, COOR or -COOC2H4OR (R: alkyl). The quinophthalone moiety can be used in combination with an indigo dye. A dyeing process making use of the above dye and denim cotton yarns thus dyed are also disclosed. Yarns can be dyed by exposing them (1) to a mixed bath containing an indigo dye and the quinophthalone dye, or (2) to separate dye baths which individually contain one or other of these dyes.