Keeping wool in shape (1983)
By Robert KertonJune 1st, 1983
Australia may no longer “ride on the sheep’s back” but wool is still one of our major industries.
That wool has managed to remain competitive in an increasingly synthetic world is partly due to the fibre’s remarkable natural properties. But it is also because science and technology have constantly been applied to enhance these properties and to improve the efficiency of wool textile production.
This film looks at some recent Australian advances in wool science – from new methods for washing and spinning raw wool to technologically advanced techniques for dyeing, shrinkproofing and printing wool textiles.
[Sheep grazing in a field appear on screen with the title: Keeping Wool in Shape]
[Image changes to show people shearing sheep]
Narrator: This is fine Australian Merino wool. It may seem like greasy, dirty, crinkly stuff but it has some remarkable properties. It can produce some of the finest and most sought after fabrics in the world.
[Music plays and the image changes to show a model swirling in a brown woollen skirt]
It’s what happens between the wool coming off the sheep’s back and getting onto your’s that makes it so attractive.
[Image changes to show wool being tested in a laboratory]
What happens of course is that a lot of science and technology is applied to the raw wool and there’s nothing new in this.
[Image changes to show black and white drawings of ancient people using looms]
For thousands of years people have been developing techniques for turning the hair of animals, into textiles.
[Image changes to show different black and white pictures of the first European settlers]
The first European settlers in Australia were quick to see the potential for wool growing and before long the country was said to ride on the sheep’s back. Developments such as the invention of mechanical shears in the 1880s helped expand the industry to the point where Australia became the world’s major wool producer.
[Image changes to show a bale of wool in the shearing shed being labelled]
Wool is still one of our major industries with exports worth almost two thousand million dollars a year.
[Image has changed back to models walking the catwalk in different woollen clothes]
For the clothing industry, wool has an appeal which synthetic fibres have not been able to match. That appeal is largely due to the natural qualities of wool, qualities that have been enhanced by extensive scientific research.
[Image changes to show inside the CSIRO’s Division of Textile Industry plant]
At CSIRO’s Division of Textile Industry in Geelong, researchers have been finding ways to improve virtually every stage of wool textile production.
[Image changes to show a big pile of wool being readied for scouring]
The first step is to wash out the dirt and grease. It’s a process called scouring and it produces large amounts of effluent which can be difficult and costly to dispose of safely.
[Image changes to the camera panning over the pilot scaled plant]
This is a pilot scale plant developed by CSIRO which offers a new approach to the problem. It’s called Lo-Flo and produces only a quarter of the usual amount of the liquid waste. Most of the dirt and grease is removed from the wool in the first washing stage. The dirty water is then piped into two centrifuges. One extracts the dirt from the water and the other the grease.
The water is then returned to the system to continue washing.
[Image changes to show the wool washing process in action]
Scientists have found that the system not only reduces the amount of effluent but increases the amount of grease extracted. The grease, what’s more, is a valuable by-product and is used for the manufacture of lanolin and cosmetics.
[Image changes to show the clean wool being moved along a new belt in preparation for the carding process]
The scoured wool is then dried in readiness for the stage which is called carding. Carding breaks open the entangled wool and removes vegetable matter and burrs. Any remaining burrs, as well as short fibres, are removed by a combing machine.
[Camera zooms in on the combing machine in action]
The wool fibres are now aligned, ready for spinning.
Spinning accounts for about 50% of the costs in yarn production.
[Image changes to show the spinning process]
Worsted yarns, used for producing suits and skirts fabrics, are made from long fibres which are spun into a fine yarn. Single yarns are not strong enough to withstand the stresses of weaving so two are wrapped around each other in a process called twisting.
Researchers at Geelong have come up with a simple way of combining spinning and twisting into a single process with a system they call Sirospun.
It represents savings of up to 40% over conventional systems.
[Camera has zoomed in on the Sirospun machine in action]
Yet Sirospun is incredibly simple and can be readily adapted to existing machines. Spacing devices are fitted to a machine in such a way that two strands of wool are brought together with twist in each yarn as well as folding of the two yarns about each other. A small plastic breakout device is the second essential element. If one strand breaks it’s important the other doesn’t keep spinning by itself. So the device flips over, prevents the twist being inserted and the yarn breaks. The operator can then the re-join the ends and start again.
Since it was introduced in 1981, Sirospun has been fitted to over 60,000 spindles throughout the world.
[Image changes to show the camera panning over different fabric samples and then to models possing]
The savings of the Sirospun process have made it economical for many manufacturers to produce fabrics like these.
[Camera pans over different shades of yarn]
Unlike worsteds, woollen yarns are designed to remain fluffy. Dying these yarns can take up to two hours of boiling in large vats.
[Image changes to show the prototype machine in action dying yarn]
But this radical prototype machine can achieve a similar result in less than ten minutes. It continuously dyes a single thread of yarn at between 300 and 600 meters per minute. The most difficult stage in the system is application of the dye, a stage which has foiled previous attempts by German and French companies to develop continuous dying machines. The next stage is to fix the dye which is done in this “J” shaped tube where the yarn is steamed for about eight minutes. Inside the tube it looks like a nasty tangle of worms but miraculously the dyed yarn can be drawn out and wound without trouble, ready for knitting.
[Image changes to show the dyed yarn being wound around a spool and then to a shop assistant adjusting a knitted jumper on a mannequin]
Knitted garments are very versatile but have always had a major drawback, shrinkage. Just why wool tends to shrink deserves a closer look.
[Image changes to show a scientist looking at wool under a microscope]
Under a scanning electron microscope a single wool fibre can be magnified thousands of times. Scales on the surface of each fibre interlock when a woollen garment is washed preventing the fibres returning to their original positions hence shrinkage.
[Camera pans over a rack of Superwash jumpers]
This Superwash jumper has been treated by the CSIRO Chlorine-Hercosett process which coats the fibres with resin so they won’t catch on each other.
[Image changes to show a scientist putting a jumper into a rotating tube]
Another process for preventing shrinkage uses chemical bonds to tie fibres together. To test the effectiveness of shrink proofing experiments, researchers subject wool fibres to up to twenty hours continuous washing in these rotating cubes. If they can survive this, they can survive anything, even printing.
[Camera pans over samples of different printed fabrics and then shows two scientists in a laboratory]
Printing patterns onto wool fabrics has always been difficult and expensive.
But this CSIRO developed process, called Keratrans, could change all that. Transfer papers, printed with specially invented dyes are placed in contact with the wool fabrics. The wool has been pre-treated to make it more receptive to the dye. It’s by far the simplest and cheapest printing system developed for wool and it’s the first that will allow photographic images to be printed on to wool fabrics.
At the Division of Textile Physics in Sydney, a very different but similarly economical system is being developed for printing wool fabrics.
[Image changes to show a scientist operating the machine as described below by narrator]
It uses the technique of jet printing in which fine jets of dye are literally sprayed onto the fabric.
[Image changes to show the pictures on the computer screen]
A computer is used to control both the pattern design and the printing process, resulting in a system which is both quicker and more efficient than the usual silk screen methods.
It’s a long way from the good old Merino to the computer controlled multi-jet printer, but it’s appropriate that Australian ingenuity in the 1980s, is helping keep one of our oldest industries alive and well in the international marketplace.
[Music plays and image changes to show researchers working with the continuous dying unit]
[Credits: A CSIRO film Commonwealth Scientific and Industrial Research Organization, Australia Copyright © 1983]