The effective pH for thioglycolate waving solutions is 9.2-9.3 using ammonia as the alkaline source. Clouding agents are included in the majority of cold wave lotions for either esthetic, wetting or conditioning properties. Surfactants may be included as opacifiers, thickeners, wetting agents or solubilizers. The neutralizers used in cold wave processes are dilute aqueous systems containing sodium perborate, sodium or potassium bromate, hydrogen perocide and sodium or potassium tetrathionates. These mild oxidizing agents will cause a hardening or setting of the curl in five to fifteen minutes.
Hair straightening products are closely related to waving products.
Quite often the same process is used to straighten the hair as is used to curl it. While most modern hair waving is accomplished by chemical means, hair straightening today is still accomplished by physical means and the use of alkalinity as well. Physical straightening employs the use of pressing oils applied hot while the hair is being combed or stretched straight. Pressing oils generally contain waxes, perfume, lanolin and other hair conditioners in a petrolatum base. The alkali type of straightener is used primarily by men, where straightness is desired and no styling required.