Shaping keratin fibres, esp. human hair or wool - involves rinsing after redn. with aq. soln. of inert substance limiting increase in dia. of fibres

摘要

In the shaping of keratin fibres, fibres are (a) treated with a soln. contg. a reducing agent to break the cystine bonds in the fibres, (b) rinsed, (c) treated with an oxidising agent to re-form the cystine bonds, and (d) rinsed. After step (a) the fibres are rinsed with an aq. soln. of a substance inert to the fibres, so that at no point in the rinsing is the dia. of the fibres more than 30% greater than at the end of the redn. step. At no point in the rinsing is the dia. of the fibres more than 10% greater than at the end of the redn. stage; pref., there is no increase in dia.. Rinsing causes a redn. in the max. increase in fibre dia. of at least 20% (at least 50%), w.r.t. rinsing with water. Rinsing soln. has an osmotic pressure, w.r.t. water, at 25 deg.C, of 6-380 x 10 power(5) Pa, and is an aq. NaCl soln., esp. contg. 10-350g NaCl/l. After the start of the rinsing with the soln. of inert substance, water is added (dis)continuously to reduce the concn. of the inert substance, until rinsing is with water alone, or rinsing with the soln. of the inert substance may be followed by rinsing with water. Inert substances may be physiologically acceptable Na, NH4, K, Li, Mg, or Al salts (pref. chlorides, bromide, sulphates, acetates, citrates and/or lactates), betaine, ethanol, glycerol, and/or D-sorbitol. USE/ADVANTAGE - Fibres are human hair or wool, and the process is esp. used in permanent waving of hair, but may also be the fixing of wool flat goods, or the permanent pleating of clothing. Damage to the fibres is reduced.