GB456336A - Improvements in and relating to the treatment of fibres or fibrous materials containing keratin - Google Patents

Abstract

A method of removing stress from or applying a set to fibrous substances containing keratin such as wool or hair comprises treating the fibrous substances with an acid sulphite solution at temperatures of about 50--60 DEG C. and under such conditions that the solution in contact with the fibrous substances is at approximately pH6 whereby there is obtained a disruption of the constituent disulphide or cystine bonds of keratin and a relief of any stress in the fibres followed by the formation of further linkages in or between the fibre molecules. The acid sulphite solution may be circulated around the material being treated at a pH of 6 or may be applied at a pH of about 8 in small amounts which react with the material and are reduced to a pH of about 6. In an example hair after a preliminary shampoo is treated with a half molar solution of sodium metabisulphite and sulphite in water containing 5 per cent of alcohol, the proportion of sulphite and metabisulphite being such as to give a pH of 6. The solution is circulated about the hair wound on a curler for about 15 minutes as a temperature of 50--60 DEG C. If preferred a 12 per cent sodium sulphite solution to which metabisulphite has been added to attain a pH of 8 may be used without circulation. In either case after the treatment, with the hair still preferably on the curler a solution of an aldehyde or a ketone, e.g. 60 per cent acetone is applied for 2--3 minutes to combine with the excess bisulphite. Treatment with a mild oxidizing agent, e.g. a 2--10 volumes hydrogen peroxide solution, preferably made acid, a percarbonate perborate or persulphate may follow or replace the treatment with aldehyde or ketone. Ordinary washing and finishing treatments follow. If desired a thickening agent such as agar-agar or kieselguhr may be added to the reducing solution to form a paste with which the hair is formed into waves or curls on the head. Suitable wetting agents may also be added to the paste, which is left in contact with the hair for about 15 minutes and then raised to a temperature of about 50 DEG C., e.g. by a stream of hot air (the hair being covered with a water impermeable cap) to set the waves or curls. Alternatively the hair may be formed into waves or curls and then treated with the reducing solution. The reagents may be applied by spraying. The treatment may be used in place of the usual crabbing or blowing treatments of wool, for the removal of distortion in knitted fabrics due to uneven stress in the yarn or yarns for the manufacture of curl fabrics or artificial astrakhan and persian lamb fabrics may be permanently set by the method of the invention.