WOOL & SHEEPSKIN INFO
WOOL & SHEEPSKIN
WOOL..the miracle fiber, is produced by all varieties of sheep. However, not all wool fibers are equal. Wool varies significantly in fiber length, fiber diameter and usefulness. One variety of sheep stands out for its usefulness in medical situations..the Australian Merino. Merino sheep produce the finest fibers and the most dense pelts, making them the number one choice for pressure sore prevention.
As with all living things, not all Merino sheep are the same. About 1 in 20 tanned pelts prove to be ideal for pressure sore prevention. These select Australian Medical Sheepskins AS4480.1, are identified by the stamp attached to the leather backing.
Wool- the Miracle Fiber; is one of the oldest and most versatile textile fibers known to man, having survived the test of time. With modern sheep breeding and improved processing technology, wool is now being used in more applications than ever before. Wool now plays a significant role in pressure sore prevention and treatment.
- Wool: Its properties and the benefits of using it for medical conditions
- Combed Wool : Footcare Lambswool, Pressure Smart XD and Nursing Fleece
- Sheepskin production ( Australian Medical Sheepskin)
- Wool and Sheepskin Care with Woolskin
Before you go any further, you can check out the CSIRO Brochure ( Australia's government research body) which describes the Physical and Chemical Nature of the Wool Fiber.
Wool surely is the "miracle fiber!" Today, there are many fibers, but as yet, science has been unable to find or produce another fiber that has all of the properties of wool. Wool, for medical use, is either shorn from the sheep to produce Hospital Nursing Fleece, Lambswool products or left attached to the hide to create the Australian Medical Sheepskin.
Wool is special because :
- Wool is a natural insulator, trapping air within and between its fibers. Wool insulation is enhanced by the crimp or waviness of the wool fiber. Crimp ensures the fibers stand apart from each other, ensuring air is trapped between them. This layer of trapped air is an excellent insulator- still air being one of the best insulators found in Nature. Wool used in footwear will keep feet warm when it is cold and near body temperature when it is hot. Trapped still air is most pronounced in sheepskin and wool-pile, making them excellent insulators against heat loss or heat gain. Sitting or lying on sheepskin or wool-pile insulates the user from the underlying surface. This means that the body is kept at an even temperature and the user feels more comfortable.
- Wool absorbs and wicks moisture, keeping your skin dry. In cold weather, even a little moisture on the skin will chill the skin; quickly reducing body temperature. In fact, the fibers can absorb up to 34% of their weight in moisture vapour without feeling wet; ten times as much as any synthetic fiber. The porous structure of the wool fiber also explains why wool is such a good thermal insulator, even without mentioning the mesh of the fibers, which creates millions of air pockets that further help to regulate temperature and humidity. During manufacturing, moisture is added to wool to increase elasticity and eliminate much friction.
- Wool is resilient, spreading body pressure and reducing pressure points. Each fiber acts like a mini-spring. Wool is also a naturally strong fiber. It can bend back on itself 20,000 times without breaking. Compare this to cotton at 3,200 times, silk at 1,800, and rayon at only 75 times. Maximum pressure reduction has been found when the pile is clipped to 30mm, is homogeneous and of uniform length and density. Australian Medical Sheepskins have these properties together with a well defined staple and crimp. It is also has a straight to light curl appearance, is free of pilling, vegetable matter and felted wool.
These criteria must be met before a sheepskin can be classified as an Australian Medical Sheepskin (AS4480.1). All of our HiTemp UR Medical Sheepskins exceed the above standard and are dyed a rich emerald green color- for identification purposes; as prescribed by the Australia Standard: AS4480.1
These properties result from the structure of its fibers, which absorb moisture, insulate against heat and cold, resist flame, and maintain their resilience. Unlike cotton, linen, silk or polyester, wool fibers are composed of a central protein core that is covered with tiny scales, making them look like pine cones..see below.
Scanning electron micro-graph of common fibers
Although the scaly surface of wool fibers tends to repel liquids, the fiber core is highly absorbent, taking in as much as 34% of its weight in moisture without feeling wet. Synthetics, in contrast, hold as little as 2% moisture. By drawing moisture away from the skin, wool prevents clamminess in summer and helps to hold in heat during winter.
These overlapping scale edges all point in the same direction. Scales of adjacent fibers may interlock, causing felting and shrinkage. Such interlocking is irreversible. This means that wool that has shrunk or felted cannot be retrieved. When wool is washed, the scales act like a ratchet, causing fibers to move against one another. The scales also act as minute barbs, locking adjacent oppositely orientated fibers together. Fiber movement causes this locking action and the wool shrinks and/or felts.
However, shrinkage and felting can be prevented by treating the wool with the Canadian Kroy process- also known as the Chlorine- Hercosett Process. Wool fibers are subjected to a mild treatment with chlorine and then a soft resin is applied. On heating, the resin forms a film over the scales and prevents fiber interlocking. Wool treated by the Chlorine- Hercosett process is also know as SuperWool.
- Wool is fire resistant. Wool is naturally safe and does not have to be treated to become inflammable. The low inflammability is due to the high Nitrogen to Oxygen ratio. While it can catch alight, it will not flare up nor support a flame. Once a flame is removed, a cold ash is left. This can be brushed away immediately. Wool does not melt when burned, and so cannot stick to the skin and cause serious burns. Because of these properties, wool fire blankets are effective in smothering a flame. Wool fibers contain about 15% moisture allowing them to resist flame without any additional chemical treatment. The wool will just char and self extinguish; giving off little heat.
- Wool is non-allergenic.There is very little scientific evidence that wool allergy exists. What is often perceived as an allergy is the prickling caused by coarse wool. Any suspected allergic reaction to wool may also be caused by dust mites in the wool. Research has shown that many people are in fact allergic to dust mite urine and feces, rather than the mites themselves. Woolskin- the Lambskin Shampoo and Woolwash has been tested by WRONZ ( Wool Research Organization of New Zealand) and shown to kill and remove mites from wool and sheepskin. We recommend that all of our products be cleaned with Woolskin.
- Wool wicks moisture: The porosity of the cells in the outer layers of wool fiber allows them to quickly and efficiently wick and evaporate moisture. Moisture wicked away from the skin keeps the skin dry and comfortable and helps to prevent skin breakdown in people susceptible to pressure sores.
- Wool is a sustainable resource.
Combed Wool and Wool-Pile Production:
- Shearing: Sheep are shorn once per year, usually in the spring. Merino sheep need to be shorn at least once a year because their wool does not stop growing. If the coat is allowed to grow, it can cause heat stress, mobility issues, and blindness. After a sheep is shorn, a shed-hand picks the fleece up off the floor and throws it on to the wool classing table. Here, another shed-hand removes seeds and short or inferior pieces of wool from the edges of the fleece. The wool classer then classifies the fleece based on the wool properties of crimp, staple, fiber diameter and elasticity.
- Scouring: Select fleeces are washed to remove impurities, such as dirt, grease, grass seeds, burrs, and dried sweat. Impurities may account for 30% - 70% of the fleece weight. At this point, the wool is considered cleaned wool or scoured wool. The grease, mainly lanolin, that is removed is considered a valuable by-product. Lanolin, in its purified state, is used in creams, soaps, lotions, cosmetics and ointments.
- Carding: The wool is combed to straighten and untangle the fibers.
- Knitting: Carded wool in the form of a rope is used to produce Footcare Lambswool. Loose carded wool is also used to produce Wool-Pile; using the Sliverknit process. In this process, fibers are sent through a series of special carding machines that comb the fibers, aligning them parallel to one another. They are then gathered into a soft rope called roving or sliver - hence the term sliver knitting. The slivers are then fed into electronic knitting machines. The machines fine gauge needles, rotating in a circular motion, pick up fibers from each sliver in a predetermined sequence, locking them directly into a soft but strong polyester knit backing. Secured at one end, the fibers remain upright and perpendicular to the backing, allowing them to maintain their resilience, softness, breathability, comfort and light weight. After knitting, the wool-pile fabric is clipped to 30 mm for final use. SuperWool Underlays and Hospital Nursing Fleece products are produced this way.
Australian Medical Sheepskin Production:
About 1 in 20 sheepskins are good enough to be classified as an authentic Australian Medical Sheepskin. Those that do meet the standard are treated as follows:
- Raw Skins:
Our raw sheep hides are obtained by the tannery from meat packing houses. Skins that meet the Australian Standard AS4480-1 1998 are selected after tanning. The hides are selected for size and wool fiber properties. The leather must be free from excessive natural fat and grease, clean and free from faults such as large holes. Seed scar is permissible but seed is not.
The raw hides are washed several times to clean and prepare them for tanning.
The skins are tanned so that the wool and the leather are preserved. This makes them usable in Institutions and for personal home use. Chromium tanning ensures good durability of both the wool fiber and leather backing. The degree of tannage is measured by the shrink temperature. HiTemp sheepskins are tanned to the highest level and have a minimum shrinkage temperature of 110 oC. This means that the skin will not shrink more than 5% when placed in water at this temperature for one hour. Glutaraldehyde ( a disinfectant) is used in conjunction with the main tanning agents to add increased resistance to urine and perspiration.
Lambskins and sheepskins contain natural grease within their structure. This has to be removed by degreasing solvents. Otherwise, a medical sheepskin would have an offensive odor and would be a health hazard. The solvents are removed from the skin during further processing. This is an important step in the tanning process and insures that a skin will remain soft and silky.
Skins are dyed a rich green emerald color; according to the Australian Standard AS8840.1 This dye is colorfast- it has to be. It may however, cause staining of bed clothing in cases of prolonged exposure to heavy perspiration. This should not be a problem when 100% cotton or cotton/polyester fabrics are used. Nylon should be avoided.
Lastly the skin is buffed smooth and the wool side is trimmed, brushed and ironed to a silky finish; using the latest technology.
Some of our HiTemp UR products are made from skins that have been perforated by an array of small holes (AirTech). AirTech assists air circulation through the leather.
Washing Wool-Pile and Sheepskin:
Wool, whether it is combed, part of a sheepskin or knitted to form Wool-Pile; will shrink and felt if mistreated. The major causes of shrinkage and/or felting are agitation and high temperatures. Rubbing wool fibers against one another will cause felting. Placing untreated wool in the dryer will result in shrinkage.
Careful washing and drying will maintain the hand or feel of wool and give articles an extended useful life. Click on washing instructions for the best way to wash sheepskin and wool-pile.
Use Woolskin- the Sheepskin Shampoo & Woolwash with conditioners. Woolskin contains: Tea Tree Oil; a natural anti-bacterial and anti-fungal that kills house dust mites- a major cause of house dust asthma.