BWF-436 Color Fixing Agent for Reactive and Sulphur Dyes BWF-436 is a formaldehyde-free cationic polymer fixing agent for reactive and sulphur dye aftertreatment. It is available in 50 ± 0.5% and 60 ± 0.5% solid-content versions and is intended to improve wet and washing fastness, with recommended fixation at 50-70 °C. Product overview BWF-436 is supplied as a light yellow viscous liquid that dissolves readily in cold water. The grade is intended for dyed textiles where wet