PURPOSE: To prevent the generation of processing defects in the dyeing of a polyester fiber by removing oligomers to cause the generation of dyeing speck.
CONSTITUTION: This fiber treating agent is composed of (A) an anionic nonionic surfactant expressed by formula I (R is a 8-21C alkyl; (n) is 10-60; X is H, Na or K), (B) a cationic organic compound of a quaternary ammonium salt expressed by formula II (R1 to R4 are each a 10-30C alkyl), formula III (R5 is a 3-24C alkyl; R6 is H or CH3) or formula IV (R7 is a 1-21C alkyl) and (C) a polymer containing carboxyl group and/or a polymer containing a salt of a carboxyl group, e.g. a (meth)acrylic acid polymer preferably having a molecular weight of 500-500,000. A polyester fiber is treated with a mixed water-soluble treating liquid containing the fiber-treating agent and an alkali agent (highly effective caustic soda) at 60-140°C, preferably 80-100°C. The mixed aqueous solution can be added at an arbitrary stage before, during or after dyeing, however, it is preferable to add the solution when the temperature reaches the above temperature level during the temperature decrease after dyeing.
MATSUDA ISAO
SAITO KOICHI