How to Bleach Cellulosics Using Continuous Method

It is very important that the goods to be dyed are pre-scoured to be free of any processing chemical additives such as sizes, waxes, oils, peroxide,  chlorine, or natural contaminates.

 

Bleaching is necessary if the desired dyeing is a light pastel shade or a very bright shade.  This process may not be necessary for dull, earthtone, dark, navy, or black shades.

 

Do not exceed a pH of 9.0 when bleaching rayon as the rayon will begin to saponify.

 

  1. Saturate goods in bleach bath containing 1-3 % owb hydrogen peroxide 50%, 1.0 % owb sodium silicate, 0.2-0.6 % owb sodium hydroxide, and 0.25% owb Anionic Wetting Agent.  pH should be about 10.5-11.0 for cotton.
  2. Pad goods and steam for 20 minutes to 1 ½ hours, depending on equipment and type of steam.
  3. Wash goods through two water baths; first at 160°F(71°C) for 15 seconds   then 75°F(24°C) for 15 seconds.
  4. Dry.

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