How to Pre-Scour & Bleach Cotton, Rayon, & 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.

 

Pre-Scour

  • Enter goods in bath containing:
  • 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
    • 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
    • 0.5-1.0 % owb         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 .

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