Patent GB-441277-A (GB)
Title: Improvements in the treatment of cellulosic filaments, yarns, ribbons and the like
IPC: D06M15/05
Filed: 1934-07-16
Abstract: A process for the manufacture of products having different properties along their length, comprises applying to filaments, yarns, tapes, straws and similar materials having a basis of cellulose, a composition comprising an organic derivative of cellulose which is not removable from the material by treatment with media containing high proportions of water, so that products are obtained having a content of organic derivative of cellulose which varies along their length.  The composition may be applied so that the whole length of the product contains organic derivative of cellulose in varying proportions, or portions of the product may be entirely free from cellulose derivative, while the other portions have a uniform or non-uniform content of cellulose derivative.  The cellulose derivative may reside only in the outer layers or may extend throughout or substantially throughout the cross-section of the products.  Slubs or similar effects may be produced on yarns.  The cellulosic materials treated may be natural, e.g. cotton or artificial, e.g. obtained by the viscose, cuprammonium or nitro-cellulose process.  The composition may be applied to filaments during their travel from one point to another or they may be treated in the form of hanks, skeins or the like. The cellulose derivative may be applied in a printing paste, but is preferably applied as a solution, an applying means such as a wick being moved, e.g. into and out of contact with the yarn or vice versa.  The composition may also be applied by spraying. Suitable methods and apparatus for applying the cellulose derivative are described in Specifications 325,823, 332,263, [both in Class 2 (ii)], and 412,600.  Yarns in hank or similar form may be partially immersed in a solution of cellulose derivative, and raised or lowered after a time.  Or different portions of hanks may be immersed in cellulose derivative solutions of different strengths or in solutions of different cellulose derivatives.  Examples of suitable solvents for the cellulose derivative solution are acetone, methylene ethylene ether, dioxane, benzene and methylene chloride or mixtures, e.g. of methylene or ethylene chloride with methyl or ethyl alcohol. The yarns may be pre-treated, e.g. with a thiocyanate, such pre-treatment may effect a substantially uniform swelling of the materials throughout their cross-section or a mainly superficial swelling.  A cellulose ester may be applied along the whole length of a product, which is then subjected to irregular or intermittent saponification, e.g. as described in Specification 332,263.  Again a yarn uniformly treated with a cellulose derivative may be treated to effect intermittent or irregular removal or decomposition of the derivative, e.g. by treating it intermittently with a suitable resist such as water-soluble acetone - insoluble methyl cellulose.  In an example, a 20 per cent solution of cellulose acetate in acetone is intermittently applied to a travelling yarn by means of a wick, and the yarn is dried.  In another example a regenerated cellulose yarn uniformly impregnated with cellulose acetate by soaking in an acetone solution is treated intermittently with a suitable resist, e.g. gelatine, and the cellulose acetate is removed from the unresisted portions by treatment with acetone.  The resist is then removed and the yarn dried.  The products are particularly useful on account of their differential dyeing properties.  The products may be treated with swelling agents for both constituents of the products to effect shrinkage which increases extensibility, or to render possible stretching to increase tenacity.  Alternatively, agents having a swelling action on only one constituent of the product may be employed to produce cockled, crinkled or other effects.  This is particularly useful for yarn to be used for staple fibre for spun yarn.  Suitable swelling agents for the cellulose are aqueous solutions of zinc chloride and thiocyanates, and for the organic derivative of cellulose are thiocyanates, acetone, methylene ethylene ether, dioxane, diacetone alcohol, methylene and ethylene dichlorides and ethyl acetate.