NEW RANGE OF DYESTUFFS

Otago Daily Times, Issue 22830, 14 March 1936, Page 14

NEW RANGE OF DYESTUFFS

PERFECT DYES FOR ACETATE SILK (From Our Own Correspondent) (By Air Mail) LONDON, February 15. A development of the first importance to the future of the acetate silk industry lies in the production of an entirely new range of dyestuffs, to be known as the Solacet Colours, which satisfy perfectly the requirements of the cellulose acetate fibres. Ever since the introduction, immediately after the war, of artificial silk made from cellulose acetate British dyestuffs chemists have led the attack on the problem of finding satisfactory dyestuffs for the direct dyeing of the new yarn. It was their pioneer work that made possible the great develop ment of the world rayon industry, and it is fitting that they should now set the crown on their labours by the perfection of the new colours.

In the early days it was impossible to dye cellulose acetate fibres directly and effectively, so that before the acetate industry could expand efficient dyestuffs having an affinity for the new fibres had to be found. Feverish efforts were made by research chemists of the British dyestuffs industry to solve the problem. The first welcome results came in 1922, but the new dyestuffs—the lonamines—required a development method which made them none too easy to apply. This process was eliminated in 1924-25 by the discovery of a range of easily applicable fast colours (the Duranol colours), supplemented later by other dyestuffs (the Dispersol colours). Both types had a direct affinity for cellulose acetate and were applicable by simple immersion of the acetate silk, but they were insoluble in water and could only be regarded as temporary substitutes for the perfect dyestuff. , . , The new colours are ideal in that thev have a direct affinity for cellulose acetate and their application can be more accurately controlled than has ever before been possible. They are soluble in water and do not therefore rely on dispersion for successful application. They can be used direct and dveing can be controlled by temperature or additions of common salt to the bath—a point which will .be appreciated by all using dyestuffs on cellulose acetate fabrics. They enable silk to be treated similarly to cotton dyed with direct cotton colours. BRITAIN'S SUPREMACY SINCE THE WAR. This latest achievement of the British dyestuffs industry affords a convenient excuse for summarising the brilliant record of this industry since its rebirth during the Great War. Although synthetic dyes were a British discovery, it is common knowledge that during the period 1880-1914 the industry was allowed to fall almost entirely into the hands of Germany. To-day Great Britain produces 90 per cunt, of his requirements of chemical and since 1918 no fewer than four of the six outstanding world developments in the whole field of synthetic dyes and pigments have been entirely British. They are: Napthol Ice Colours (Gorman), Caledon Jade Green (British), Duranol colours (British). Tndigosol products (Swiss), Soledon colours (British), Monastral Fast Blue BS (British). The most interesting of these are Caledon Jade Green, which is the fastest dyestuff known and of great use where high quality has to be combined with hard wearing, as for curtains, carpets, etc., and Monastral Blue, which is the first blue pigment to be discovered for over 100 years and combines all the properties required in a pigment by the using trades-. The significance of the discovery of Monastral Blue may be appreciated by considering for a second how seldom it is that any addition can be made to the known range of colours in the artist's paint box. . , It is therefore not surprising that the exports of British dyes-tuffs in quantities and values are as follows: ]()'?4 .. . r )o,t33cwt £691,103 1934 . .. 89,575 cwt £1,049,495 1935 .. .. 101,332 cwt £1,232,310 AX EXPANDING INDUSTRY. Prior to 1914 Germany had practically a monopoly of dyestuffs manufacture, and there were in Great Britain loss than a dozen manufacturing companies, most of whose raw materials came from abroad, the dyestuffs being merely assembled in England. All but 20 per cent, of British requirements were imported. With the advent of the Great War, plant and raw materials had to be produced and technical staff recruited and trained in the most difficult circumstances before it was possible to tackle the main problem of manufacture. After several initial years of laborious imitation order came out of chaos. Real creation became possible and the industry progressed by leaps and bounds. Since 1918 four of the six major developments in dyestuffs chemistry have been British discoveries. To-day practically all Great Britain's requirements are manufactured at Home, and the industry is one of the very few which has continued uninterruptedly to expand all through the economic depression.