Effects of Some Relaxation Treatments on the Waving Performance of the Permanent Waving Procedure of Human Hair

Abstract

The relaxation behavior on the permanent waving performance of human hair were investigated. According to a standard procedure simulating commercial practice, hair tresses were wrapped on a rod 12mm in diameter and were waved by immersing in 5% thioglycolic acid solution, rinsing with water and neutralization with sodium bromate solution. The relaxation processing was applied after water rinse and carried out remaining the rod under the various conditions for a certain period of time. The effects of the relaxation processing were observed for the hair samples treated for 3-15 minutes with the reduction solution. This wave imparted by added relaxation processing was stronger and shorter than in the absence of relaxation. This indicates that the mechanical relaxation may occur simultaneously and moderately with the protein chains of keratin structure with a much lower conversion of disulfide to sulfhydril group. Accordingly, if the permanent waving of hair is carried out by the produce involving the relaxation processing, the reduction state in the hair necessary for the protein chain rearrangement to equilibrium with the curled configuration can be attained with a smaller concentration of sulfhydril groups, so that the permanent waving produce involving the relaxation processing results in major benefits of fiber degradation as observed by appearance and feel.