Abstract
C. I. Reactive Blue 19 (applied in the vinylsulfonyl-form), one of the sulfatoethylsulfonyl reactive dyes, was treated in buffer solution of pH range 7.1-10.2. The resulting ether-form was investigated on the amounts of formation, the stability and the dyeability.
The following results were obtained:
1) The maximum yield of formation of the ether-form from the vinylsulfonyl-form was 37.15% at 60°C, 18.55% at 80°C.
2) The ether-form was very stable in neutral solution at 60°C but considerably decomposed at 80°C even in pH 7.19.
3) The ether-form did not fix for degummed silk in acidic condition but did in neutral or alkaline solution and then the maximum fixation was about 30% at 80°C.
4) When the ether-form was treated in buffer solution, the formation of the vinylsulfonyl-form was observed. In addition, the ether-form exhibited a considerable fixation for degummed silk as mentioned above. For these reasons, it seemed that the following reaction was occurred both in aqueous solution and on silk fber: Ether-form _??_ Vinylsulfonyl-form+Hydroxyethylsulfonyl-form From these results it was considered that the existence of the ether-form was negligible in the silk dyeing under the following condition: Temperature: 80°C, pH: 7-9, Time: 1-2hr
