How to Pre-Scour & Bleach Cellulosics
It is very important that the cellulosic goods to be dyed are free of any processing chemical additives such as sizes, waxes, oils, peroxide, chlorine, or natural contaminates. Do not exceed a pH of 9.0 when bleaching rayon as this will initiate saponification. Bleaching processes may not be necessary for dull, earthtone, dark, navy, or black shades.
PreScour
- Enter goods in bath containing:
- 2.0% Soda Ash on weight of goods(owg)
- 2.0% owg Orcoterge ALK-N Conc™
- 0.5% owg Orco Penetrant 120™
- Raise temperature to 185°-195°F(90°-93°C) and hold for 30 minutes.
- Drop bath and rinse well.
Half-Bleach Bottom Procedure
Half-Bleach bottoms may be desired for pastel and bright shades where a full-bleach is not necessary.
- Enter goods into a bleaching bath containing:
- 3-4 % owg Hydrogen Peroxide 35%
- 1.0-1.5 % owg Sodium silicate
- 0.5 % owg Sodium Hexametaphosphate
- 0.5-1.0 % owg Sodium Hydroxide
- 0.5-1.0 % owg Orcoterge ALK-N Conc™
- Raise temperature to 185°-195°F(85°-91°C) and run for 1 hour.
- Drop bath, rinse well, adjust pH to 6.5-7.5 and dry.
Full-Bleach Bottom Procedure
For a cleaner white on cellulosics a full-bottom bleach procedure may be required. This requires a higher amount of Hydrogen Peroxide and an optical whitener may be included in the bleaching bath to enhance the white.
- Enter goods into a bleaching bath at 80°-100°F(26°-38°C) containing:
- 4-8 % owg Hydrogen Peroxide 35%
- 2-4 % owg Sodium silicate
- 0.25-0.5% owg Caustic Soda 50%
- 0.25% owg Peroxide Stabilizer
- 0.5 % owg Sodium Hexametaphosphate
- 0.5-1.0 % owg Sodium Hydroxide
- 1.0 % owg Orcoterge ALK-N Conc™
- 0.75-1.0 % owg Orco Synthrowite C-ALKS™
- Raise temperature to 185°-195°F(85°-91°C) and run for 1 hour.
Drop bath, rinse well, and adjust pH to 6.5-7.5 .