STOCKINGS

feel, looks and sheerness. Rayon can be produced in a thread as fine as silk for exceptionally fine gauges of stockings, also in a stouter thread for semi-service and service weights.

Another important point is that rayon yarns can be twisted up to a specific number of turns, this not only adding to their efficiency during knitting, but to the general construction of a stocking.

Rayon when it comes from the rayon producer has a twist of a few turns per inch, and it is possible to produce a stocking which will give satisfactory wear, and meet with consumer acceptance both from a quality and appearance point of view. The high twists now being given to rayon increase the improved appearance of the stocking by producing an effect of dullness, this being achieved by the breaking up of the light reflection, also the sheerness of the stocking is increased by the reduction of the diameter of the thread. Stockings made from this high twist have increased resistance to snagging. Undoubtedly, high twist improves the elasticity, or recoverability (the aptitude of the yarn to return to its original shape).

The conditioning of yarn is a very important factor, having the effect of:-

1. Maintaining the high twist in the yarn.

2. Helping to prevent the kinking of the yarn as it leaves the cone on which it is wound (thereby reducing “press-offs”).

3. Forming a clearer and more even stitch, resulting in the production of a better fabric from the knitting machine.

4. Protecting the fine rayon filaments against chafing by the action of the needles and other parts during manufacture.

Experiments are being made with cellulose rayon hose to improve the fit and appearance by:-

1. Reducing the slipping and twisting of the stocking when on the leg—giving a better cling.

2. Tending to give the stocking a greater resistance to snags and runs, also to chafing at heel and toe.

3. Correcting the abrasion weakness caused by perspiration.

STOCKINGS

bits called “crumbs”. The “crumbs” by means of chemicals are made into a brown gelatinous mass. They are softened and blended into a thick syrup. The syrup is then forced through the multiple holes of a nozzle, called a spinneret, which is like the rose of a garden syringe. The filaments are forced out into a coagulating bath, drawn together to form a thread, and wound into a convenient form. Before cotton fibres can be used they must be cleansed from oil, fat, wax and colouring matter. They must be boiled, bleached, dried and teased out. Then, like wood pulp, they are dissolved in chemicals and the resulting viscous solution is forced through the spinneret.

To sum up, four processes for the manufacture of rayon have now been mentioned:-

  1. Viscose.

  2. Acetate.

  3. Cuprammonium.

  4. Nitrocellulose.

They are grouped here according to the quantity produced, and not by the quality obtained. It has also been noted that the basic raw material is cellulose, which is obtained from two sources, wood pulp and cotton linters. Wood pulp, being the cheaper, is used for the standard rayon yarns, and cotton linters—the purest form of cellulose known—for the quality yarn. The cellulose is dissolved into a syrup and then drawn through the holes in the nozzle of a spinneret. This latter process is called spinning. It will be noticed that the spinning process is comparable to that of the silkworm. The silkworm exudes from its body a viscous substance, which hardens on coming into contact with air and so forms a filament. One silkworm when spinning a cocoon, will produce several miles, of silk; theoretically, a rayon spinneret could produce a never ending thread. Such threads differ basically from all other textile yarns, e.g. wool or cotton, in which the threads are obtained by spinning together short filaments which measure only about an inch.

It has been seen that the basis of all the four types of yarn used is cellulose, but rayon yarn is not limited in its variety. The yarn characteristics and qualities vary according to the process which is used for its production. The varying qualities have points of difference which are reflected in the stocking, such as elasticity,