How to Scour Raw Wool
Raw wool contains many impurities such as natural grease and oils, dirt, cellulose matter and various other contaminates both natural and manmade such as polypropylene (used in bailing materials) and twine. These contaminates may be a substantial part of the wool weight and must be removed prior to dyeing and in some cases spinning and weaving. Although a somewhat complex process, the following is provided as a guide and a general overview. One important fact that should always be remembered is that wool, although very resistant to strong acidic conditions, is very sensitive to high alkalinity especially at elevated temperatures.
Raw wool scouring is typically carried out at temperatures below 140°F(60°C) with low cloud nonionic surfactants and/or anionic detergents sometimes in the presence of emulsified solvents. An alkali such as ammonia may be used, but the pH should not be above 10 for extended periods of time and temperatures in excess of 140°F(60°C) should be avoided .
- 1.0-2.0 % owg Orconol CHSA Conc™
- 0.5-1.0 % owg Orcoterge ALK-N Conc™
- 3.0-5.0 % owg Orco Citrisolve DL-AAS-2™
- X % owg Ammonia to pH of 8.5-9.5
Raise the temperature slowly to 130-140°F(54-60°C) and maintain for 20-30 minutes. Overflow, drop bath, and rinse.
In cases where the wool is extremely contaminated, a second scour as above may be in order.