Australian Wool Textile Research (continued)

By the early 1960s, various efforts were being made to develop new uses for wool and wool products. One of these was the use of wool sheepskins as an aid in nursing.[40] Sheepskins could greatly relieve the development of bed sores. The skin is placed on the bed, with the fleece side uppermost, so that the patient lies directly on the wool. By its capacity to absorb moisture, it prevents the skin from becoming soft and sodden and, at the same time, because of its natural elasticity, the wool staple, even when compressed, will allow the air to circulate freely under the patient's skin.

The problem at that stage was, however, that such sheepskins could not withstand laundering (under severe hospital conditions), becoming hard and matted. This was solved by work at the Melbourne CSIRO[41] which led to new techniques of tanning the skin and treatment of the fleece, as well as for laundering.

On the woollen system of processing, there have been few major changes of Australian origin. Of note, however, is the work done in carbonising by the School of Textile Technology in the University of N.S.W. -a school established in 1955 to provide graduate education and research in textiles.

As already mentioned, the main problems with the carbonising process are the damage to the fibre by the sulphuric acid used, and fibre entanglement. Combined, these can lead to an unacceptable loss of fibre material by damage on the card, and the chemical damage can affect both processing and performance of the wool.

Work at the University{42} led to the development of a rapid method of carbonizing in which the wool is held between two porous conveyors while undergoing the aqueous treatment (both acidification and neutralising). This considerably reduced fibre entanglement by reducing fibre movement and offered better control also over the contact time between the wool and the acid.

The same workers also showed that, provided rapidly acidized wool is allowed to 'rest' -before drying -to allow the acid to disperse uniformly, the wool can then be dried at very fast rates (at 150°C) without chemical damage. More damage will in fact occur in slower, lower temperature drying, as practised in industry.

Following on from this, they have developed[43] a dryer -the Unidryer -which gives uniform drying and greater efficiency. This machine is being marketed by a New Zealand machinery maker, Annett & Darling Ltd.

For improved control of humidity in drying, these workers also developed the NOCH Unitrol Humidity system[44] which monitors the amount of moisture in the exhaust air and adjusts the flow of fresh air entering the dryer to maintain the desired moisture content in the exhaust stream. The unit is based on the well-known principle of wet and dry bulb thermometers but is automated to dip and wash the wet bulb to keep it free from dust and wool accumulation.

Traditionally, wool has been dyed in batch operations in which the textile -loose fibre, top, yarn, fabric or garment -is boiled in aqueous solutions of dye for periods of at least one hour. The process involves either movement of the dye solution through a compressed mass of the textile, e.g. a yarn package, or transport of the textile, e.g. an endless rope of fabric, through the dye solution. Both approaches entail the use of high volumes of dye solution relative to the volume of textile being dyed, and hence have tended to be expensive both in energy and in water (and consequently effluent treatment). The prolonged boiling also leads to fibre degradation; in some cases, 5-6 per cent of the weight of the wool is lost.

Australian Academy of Technological Sciences and Engineering