Thioglycolic acid has been widely used, not only in america, but throughout the world, for the formulation of depilatories. It is commonly accepted at the present time as "the mercaptan" to be used in depilatories. Either the straight thioglycolic acid or its calcium salt may be used. Because thioglycolates are the principal ingredients of depilatories, it is necessary (as in the case of cold waving lotions) to keep to the minimum the metallic impurities in the other ingredients used in manufacturing the product. Properly formulated depilatory creams are stable and have a shelf life of over one year. The container must be tightly sealed or the cream will rapidly lose its strength through oxidation. Although tin is the most satisfactory material for tubes, it is possible today to buy wax-lined lead tubes that give satisfactory protection. Most depilatories on the market contain about 2.5%-3% thioglycolic acid and are adjusted to a pH a
配制方法:
Depilatory is prepared in two parts and then mixed together, as follows: Part I: (For all four formulas) Heat 60 kg of distilled water to 70'C. Add the cetyl alcohol and the "Brij" 35 with constant stirring until completely dissolved. Discontinue stirring and allow to stand and cool to room temperature. Part II: (For formulas 3 and 4) To 14 liters of distilled water add the calcium thioglycolate and mix well. While stirring slowly add the calcium hydroxide. Add the 3.7 kg of strontium hydroxide at this point, only if you are using formula 3. Add sufficient distilled water to make Part II weigh 33 kg. Combine Part II with Part I and stir well. Add perfume at this point as desired. The final product should be assayed for content of thioglycolic acid, pH, and depilation time. In the manufacture of depilatories it is extremely important that the equipment used should not be a source of contamination of the product. In general, the same materials that are suitable for the handling of