GB441276A - Improvements in the treatment of filaments, yarns or the like of organic derivativesof cellulose - Google Patents

Abstract

A composition containing or yielding a type of cellulose which is not removable by scouring or similar treatments with water or dilute aqueous media is applied to filaments, yarns, tapes, straws or similar materials having a basis of an organic derivative of cellulose, so that products are obtained having a content of cellulose which varies along their length. The composition may be applied irregularly, all the product containing some cellulose or intermittently so that parts of the product contain a regularly or irregularly disposed content of cellulose, while other parts contain no cellulose. The composition may be applied along the whole length of the materials and then irregularly or intermittently removed therefrom. The cellulose may be applied as cellulose itself dissolved in cuprammonium solutions, thiocyanate solutions or zinc chloride or as cellulose derivatives from which cellulose may be regenerated, e.g. the xanthate or nitrate. When treating cellulose ether materials the cellulose may be applied as a saponifiable cellulose ester. Regeneration may be effected by suitable solutions or by gaseous reagents such as ammonia, hot air, steam, hydrogen chloride, carbon dioxide, or acetic acid. The materials may be swollen either uniformly or superficially before treatment. The materials may be treated while travelling from one point to another, e.g. by intermittent contact with a wick or by interrupted or varied spraying, or in the form of hanks or skeins, e.g. by partial immersion. In a modification, the materials are coated with a cellulose derivative, then subjected to varying treatment with a resist, followed by uniform treatment to precipitate cellulose on the exposed portion and removal of the resist and underlying cellulose derivative. Suitable methods of carrying out the process of the invention are described in Specifications 325,823, 332,263, [both in Class 2 (ii)], and 412,600. When cellulose ester materials are treated with viscose, its free alkali content should be kept as low as possible to avoid saponification. Thus, suitable salts such as ammonium acetate or carbonate may be added to the viscose, or the materials after application of viscose may be treated with salts to reduce its alkalinity. The products may be dried before regeneration of the cellulose. If desired, solutions of other soluble cellulose xanthates may be employed, e.g. of ammonium magnesium, or of organic bases. In an example, an alcohol-ether solution of nitrocellulose containing sufficient acetone to effect superficial swelling is intermittently applied to a travelling cellulose acetate yarn. The yarn is then dried, denitrated and washed. Other examples are given in the specification. The products may be treated with agents swelling both constituents to increase their extensibility or tenacity, or they may be treated with a swelling agent for one constituent only to produce cockled or crinkled effects which are particularly valuable in staple fibres. Suitable swelling agents for the cellulose are aqueous solutions of zinc chloride or of thiocyanates, and for the cellulose derivative are thiocyanate, acetone, methylene ethylene ether, dioxane, diacetone alcohol, methylene and ethylene dichlorides and ethyl acetate. The products may be dyed with suitable dyestuffs before or after making into fabrics. Irregular formation of cellulose on the materials raises their safe ironing point.