Synthesis of Benzisothiazole-Azo Disperse Dyes for High Resistance to Alkaline Treatments and Peroxide Bleaching of Polyester and Polyester/Cotton Fabric.

We proposed in this paper to design and synthesize a series of benzisothiazole-based heterocyclic azo disperse dyes with high resistance to alkali and peroxide. These newly synthesized disperse dyes were confirmed using H nuclear magnetic resonance (H NMR), mass spectroscopy, and a UV-visible spectrophotometer. The resistances to alkali and peroxide were examined by dyeing polyester fabric with these synthesized disperse dyes in sodium hydroxide solution and alkaline hydrogen peroxide solution, respectively. It was found that the disperse dyes having cyano and hydroxyl groups exhibited poor resistance to alkali and peroxide. When the cyano and hydroxyl groups were substituted with ethyl, benzyl, and -methylbenzyl groups, the synthesized disperse dyes exhibited extremely high resistance to alkali and peroxide. Utilizing the high resistance to alkali and peroxide of synthesized disperse dyes, the polyester suede fabric and polyester/cotton blended fabric could be produced by combining pretreatment with dyeing in one bath. From pilot-plant production based on 1-ton fabric, the one-bath process provided the advantages of saving electric power, steam, water, and man-hour.