In the 1930s Thioglycolic Acid (TGA) was discovered to be suitable for permanent waving of hair. As such Dr. Ralph Evans began to use TGA in the production of hair perms in the early 1940s in Hoboken, New Jersey, USA, and later has founded EVANS CHEMETICS.
The reducing properties of the SH-group open the sulfur bridges in the ceratine structure of the hair and thus weaken it. After rinsing in a second step the sulfur bridges are reconnected with an oxidizing chemical such as hydrogen-peroxide. If both steps are applied to hair tightly wrapped around hair rollers the hair fibres get its desired curled shape.
As alternative to Thioglycolic Acid and its salts or as additional ingredient to enhance the perm strength Thiolactic Acid or Ammonium Thiolactate (ATL 70 or ATL 58) are used in hair perm formulations. The Ammonium Thiolactacte is classified as non toxic so it is preferantial for non professional hair perms for application at home.
Mainly in Northamerica Glyceryl Thioglycolate (eg. GMT 80) is used in nearly pH-neutral formulations.
In the last two decades the same chemistry has been introduced also for hair straightening but with higher pH-values.
EVANS CHEMETICS offers additionally a solid alcohol mix, EVANOL®, which is supplied as flakes and can be used in cosmetic formulations. Thiodipropionic Acid is used as antioxidant in cosmetic formulations.
Products for Depilatories
TGA and its salts Calcium Thioglycolate, a crystalline powder, and Potassium Thioglycolate as an aquous solution (KTG 43) are used in high pH-formulations as depilatories.
EVANS CHEMETICS offers additionally Thioglycerol which can be used in Depilatory formulations too.
For more Information:
Dr. Tom Beyersdorff
Technical Marketing Manager
Fon: +49 4176 9098-68