RAYON

Bay of Plenty Beacon, Volume 10, Issue 36, 11 October 1946, Page 8

RAYON

Man-made silk

A Frenchman is responsible for man-made silk. About a century ago Count Hilaire Chardonnet found a sac of crystal, tarry fluid inside a silk-worm, from which the worm evidently drew the materials with which it spun silk. Chardonnet spent nearly 30 years analysing this fluid and to create his ‘nitrosilk,” .or the original rayon. But the creation of synthetic silk meant much more than that. By developing nitrosilk, Chardonnet was the first man in history to make a textile fibre.

The Frenchman started something when he took out his patent and displayed a small piece of the first man-made silk in the Paris exhibition of 1889. “Chardonnet silk” has been greatly perfected within the last 20 years. It is known to the whole world as rayon, the substitute for silk. Its cheapness has brought it into great popular demand, and a gigantic industry has sprung up for its manufacture. Rayon is principally made from pulp sheets of spruce and pine wood logged in Scandinavia, Canada, and the United States, mixed with cotton hulls. When these sheets reach the rayon factory they are placed in • properly humidfied storerooms, where a constant temperature is always maintained. Pulp-sheet conditioning and storage expense is a big item in overhead at the rayon factory, calling for a corps of “weather man,” a big cooling, and a complete air-conditioning system. The weather men stand ever vigilant inspectors over the many thermometers and barometers stationed throughout the factory. Ready for use, the pulp sheets are saturated in a tank of caustic soda, dried under the press of a hydraulic plunger and ground into ‘crumbs’ which undergo a curing process. The cured crumbs are mixed with a carbon sulphur salt solution to become the orange-tinted xanthate. The xanthate is dissolved in water' or weak caustic soda, cooled and filtered and is now the viscose product, much like that which Chardonnet found in the silkworm sac and managed, after 30 years of labour, to imitate. The viscose is passed through a machine that might well be called a silk robot, for it is very nearly an identical mechanical imitation of a silkworm. The fluid emerges from the robot as rayon fibre, is rolled into cakes, made into skeins, washed, bleached and (dried, to emerge from the factory ais soft, shining hanks of rayon yarn.