Stain resist treatments for nylon 6,6

A commercial syntan reduced the staining imparted to adjacent nylon 6,6 fabric during washing at 60 °C. The extent of staining decreased with increasing pH of application of the syntan which can be attributed to a corresponding increase in uptake of the syntan. Stain resistance increased with increasing temperature of treatment due to the higher kinetic energy of the syntan molecules and the greater extent of fibre swelling at higher temperatures. The level of staining decreased with decreasing liquor ratio owing to a corresponding increase in the effective concentration of syntan in the treatment bath; increased syntan aggregation in the application of liquor may also have contributed to the greater uptake of the polycondensate at low liquor ratio. The finding that the extent of staining gradually decreased with increasing time of application can be attributed to increased uptake of the syntan. Although the use of a cationic polymer did not enhance the stain resist effectiveness of the syntan, treatment of the adjacent nylon 6,6 with the full backtan markedly reduced the level of staining achieved.