In the case of fibers from animal hair wool from sheep’s are dominating. Despite this, it is only about 3% of the world’s use that consist of this type of fiber. Because of wool's high market price the economic value is much greater.
Sheep farming and breeding is conducted in smaller scales in different countries in America, Europe and Asia, but Australia, New Zealand and Russia are the major exporting countries. Sheep farming is harsh on the vegetation , especially the re-growth of trees and shrubs. In some cases the sheep’s are treated with anti-worm and ticks substances which are sprayed on them. They may also undergo a bath consisting of some insecticides. Wool consists of proteins that serve as food for insects such as moths and beetles. Their eggs and cocoons may get laid in the wool and can start to grow and finally hatch during storage or during long sea voyages. Therefore, a pesticide was developed for these insects that tend to ruin the wool during storage, etc. Moreover, finished products are in some cases treated with mothballs or pesticides. These pesticides are often persistent and cannot be degraded in nature, they are also bio accumulative, which means that they can accumulate in living organisms.
Cutting of wool is difficult work, which often damages the animal and also the one performing the cutting. Experiments have therefore been attempted to try to get the wool to fall of the sheep after a certain amount of time using plan hormones instead of cutting. Even the wool of sheep must be freed from various impurities before it is included in the textile processes. The newly cut wool contains not only pesticide residues but also natural impurities in the form of dried sweat, dirt (clay, soil, dust) and wool fat. When boiling these impurities away there is an effect on the oxygen levels in the water which results in a negative environmental impact. Wool fat - that in raw wool can be a total of 10-15% of the weight is washed out to some extent. 4-6 % of the wool fat is left for the wool to retain its flexibility in carding and spinning. Raw wool also contains a lot of impurities such as grass and plant parts. These are removed by treatment in sulfuric acid (carbonization). Both removal through washing of wool fat and carbonization includes environmental problems. Also, some moth-pesticide is washed away along with the wool fat. Other fur hairs such as, camel, llama, alpaca, vicuna and rabbit only have a small quantity of fibers.
Environmental Facts
Topography - Animal husbandry on a large scale including sheep and goat is always harsh on the vegetation. The animals can be effectively kept in the open landscape, but in dry areas, it may lead to sparse vegetation that may be destroyed, leading to desiccation and erosion.
Parasite control - Can be useful in some breeds, depending on climat conditions.
Moth pesticides - Used to protect wool against insect attack. Many pesticides are persistent and bio accumulative and are therefore banned in many countries.
Properties
Wool is an extremely complex fiber, developed millions of years ago to protect warm-blooded animals in many different climates and conditions. In comparison, the synthetic fibers are simple and designed for limited use. Wool is very resilient and elastic, and can be bent 30 000 times without breaking down or being destroyed. Each wool fiber can be stretched out one third and then return to its original length.
Since wool absorbs water vapor, it provides a superior comfort in both warm and cold weather. In cold weather, even a small amount of moisture that get in contact with the skin can make you feel cold, and your body temperature will be reduced. Since the wool absorbs water vapor a dry layer of air is left in between the garment and the body that help keep body temperature. Air is the best insulator nature can provide and this explains why wool is able to keep the body warm as well. The wool fiber have some distance from each other and in between there are air pockets. The air which is fixed in the fiber acts as an insulator. The air pockets also help to maintain a comfortable body temperature even in hot weather. The insulation acts as a protective barrier that keeps heat out. What's so great about wool is that, while they absorb water vapor, it repels liquids. Clothing made of wool has a very good shelf life, and looks new for a long time. This is because the wool has a dirt repellent property that allows the garment to remain clean longer, and don’t need to be washed very often.
Wool has another property that is not as well known. The protein that wool is composed of is flame-resistant, making it difficult to ignite. Even the wool's ability to hold water vapor contributes to this property. Wool can catch fire, but the flame does not burn long since the fibers are only charred and the fire is put out. This characteristic makes wool suitable for use in high-risk situations concerning fire.
The production and impact on nature
Wool is a natural fiber that is both reusable and recyclable. Recycled wool is produced in a way where the old wool garment is torn or cut apart, and re-spun. This results in shorter fibers and the end result is poorer quality. Most of recycled wool is used as fill material, but to increase the quality it can be mixed with new wool, or other materials such as cotton. The amount of energy required to produce recycled wool is only half of what new wool requires. It is an advantage that it can be produced without the need of plant chemicals, but there are other drawbacks. As well as other natural fibers raw wool contains a lot of impurities such as dirt and grease. It also includes the valuable Lanolin, which is the only fiber that requires wet scrubbing before it is processed. To dissolve the fat a simple warm bath can be used, but in large scale industries detergent and alkali are used. In commercial wool, vegetable residues are removed by charring, while when dealing with less processed wool, this is done by hand using a mild detergent. When this is done by hand, the Lanolin is taken care of, and is used for cosmetics and skin creams.
In order to produce 1 kg of pure wool one also produces 1.5 kg of waste and pollution. After cleaning the fibers are sorted according to its quality and are passed along the production chain. When dealing with Merino wool one measure the amount of vegetable matter that remains in the fiber. One also measures length and strength of the fiber, and sometimes one check for color and comfort factor. Natural fibers, including wool often have a broken white color, and require bleaching to produce white or light colored fabrics. Bleaching also occurs when dyeing dark colors, to get an even result. Bleaching the fibers makes them weaker, and affects the durability. It is common to bleach with hydrogen peroxide in a wet process, and it requires a fairly high temperature to get good results. In the wool industry chromium is often used in connection with dyeing because of its color fastness and possible color spectrum at a low cost. Some dyeing processes have been developed with a low content of chromium, but when the wool is dyed in mainly black and some blue dyes, there is sometimes no alternative to achieve the same color fastness. Interest in natural coloring agent used for a long time before modern synthetic dyeing processes was used has been rediscovered. The natural dyeing methods have limited color spectrums and the color is not as durable as new methods. However, it is possible to achieve some interesting effects on the wool fibers.
To prevent that garments made of wool become wrinkled, there is a process through which every wool fiber is chemically altered and covered with a thin surface of polymers by the use of chlorine. This causes the fibers to easily slide over each other while the wool is wet. This process emits unacceptably high amounts of halogens in the drainage channels. Rules regarding the emissions vary between countries, but some countries allow the use of the process. CSIRO and chemical producers are working to develop a process that does not require chlorine. There are already polymers containing low or no levels of chlorine and the methods are being developed in attempts to get it on market.
Since wool is a natural protein, it can be attacked by moths, beetles and other pests. The sheep will be either receive injections of insecticides, or become be subjected to a bath that includes pesticides. If sheep’s are not treated it can lead to an uncomfortably well-being, which can spread throughout the flock. The chemicals used can harm both humans and rivers, and also the sheep. Previously phosphate agents for scabies were used in the chemical treatment, which has been shown to produce nerve damage in humans. Cypermethrin is less of a health hazard to humans but is 1,000 times more hazardous to aquatic life and water.
Two kinds of antibiotics are authorized to put in the food of sheep’s in order to enhance their growth. These enable the sheep’s to grows slightly faster and can compensate for the loss that occurs because of unsanitary conditions in consequence of overcrowding. Antibiotics used in agriculture end up in the groundwater and later also in the local areas drinking water. This increases the risk of resistivity of antibiotics in humans. In almost all countries, including Sweden wool is treated as a secondary product, it is the flesh of sheep’s that provides most profit. Sheep are therefore rarely bred for their wool and this means that the wool is coarse and the quality is worse than it could be. The conditions for sheep farming in Sweden is good compared to other countries and since the climate is cool and that there are large grazing areas that does not and allow parasites to spread. The Swedish sheep are bred for their meat and the wool is usually thrown away since there is no demand for it. Wool from Swedish sheep is too coarse for use in thin garments, but has several other advantages. Shades of brown, gray and black that occurs in sheep in Sweden are rare, and outside Sweden these shades are only naturally found in alpaca. Wool from Swedish white sheep is unusually shiny and resembles mohair. Australian merino sheep are bred for their wool in contrast to most other sheep. A single sheep can produce up to 5 kg of wool with high quality. They are being bred to produce as much wool as possible and this has led to that they have excess skin around the neck. The extra skin folds and attracts pests, which means that more treatment against insect infestation is needed.
In 2005, the demand for clean wool was 1.23 million tons, which represents about 2% of all textile fibers. Demand has remained at a fairly steady figure for many years, as compared to polyester, which has doubled in the past 15 years. Wool is a good fiber considering energy, since it only takes less than 10MJ of energy per kg. The acrylic fibers require more than 100 MJ per kg. However, the amount of water required is about the same. On 1 hectare of land, you get about 62 kg wool, compared to the cultivation of hemp that provides about 1200-2000 kg of fiber on the same amount of land.
Modified wool
The demand for thinner, softer, functional, and aesthetically pleasing textile increases. Ordinary wool cannot normally be spun into getting these properties. But by using a new technique, which involves modifying the fibers into silk-like this might be achieved. This is done by treating the fibers with chemical means such as sodium, hydrogen sulfite, and by a steam process where the fibers are pulled out. This results in a longer fiber that is 3-4 micron diameter smaller and with larger luster. These features allow the fibers to compete in a new market.
Instant dried Merino wool is something that CSIRO conducts research on. Wool is known to be very slow to dry, despite its water repellent properties. Some polymers have been shown to bind strongly to the fibers and reduce water to penetrate into the fibers. A single treatment should, according to researchers, last the entire life-span of the garment. The benefits of instant dried wool are that it only holds one-fourth as much water as regular wool. This means that this wool dries one fourth of the time it takes for raw wool to dry. The treated wool’s drying time is comparable to polyester which takes about 2 hours to get completely dry. This enables the wool to require less energy for drying after since the amount of water it holds is less than that of untreated wool.
Caring of wool products
Using a brush on shallow spots may prevent deeper spots to form. Stains on wool should be removed at once, and with a clean cloth, never paper. Wet wool should be avoided to be approached to a heat source, and wool should never be submitted to tumble, if it does not say that it is possible on certain washing instructions. Fanning wool can be very effective when you want to get rid of unwelcome odors. When the wool is dried, it should be hung loosely and on a good hanger so that any wrinkles can be avoided. Wool is at its best when one lets it rest one day in between uses, it provides the wool with a rest. An important rule that applies to knitwear is to never let them hang, but they should be stored folded and with access to air.
Organic wool
In order for wool to be certified as organic wool, there are several different criteria it must achieve but the hardest one is; the sheep are not to be dipped in pesticides to protect the wool from pest attacks. Also not to have more sheep in one area than the area can handle. The organic wool is more expensive for several reasons. Since it is not produced to the same extent as ordinary wool, they cannot compete with the major producers. One of the requirements to become organic is that the feeding should be controlled in the matter where the grasslands should not be destroyed. This results in fewer sheep per land area than is required for normal wool. This means that it requires more land to keep the same number of sheep. Organic wool is washed in certified organic biodegradable detergents, and nothing else, in comparison with ordinary wool that is washed with a variety of chemicals. Organic wool is today used for the same things as regular wool, however, organic wool is especially used children's clothing. The demand for the toxic-free wool increases and the market is also seeing an increase of supply.
Mulesing
Mulesing is the practice of cutting the skin off around the anus of sheep, to prevent attacks from “blue-flies”. The method is present in Australia but is according to critics’ animal cruelty. A number of measures are underway to eliminate this method. Australian Wool Industry has decided that the method shall cease to excist no later than 31 Dec 2010. Mulesing is already banned in New Zealand.
Originally the idea of mulesing was that it would be performed on sheep when they are weaned from their mothers since the surgery was to raw to do be performed on lamb. What was found was that the effect was better and the sheep were protected during longer times if the surgery was done when they were still lambs. For lambs older than 2 months the healing lasts around 2 weeks. The procedure means that the wrinkled skin of the animal’s rump to the hind legs is cut off. This takes place without any kind of anesthetic. After the surgery the wound heals and make those areas lack wool and therefore prevent feces and other particles from sticking to it and attract pests.
Sources
http://en.wikipedia.org/wiki/Wool
Sustainable fashion & textiles, Kate Fletcher
Tyg eller otyg? Fakta underlag Miljövänliga veckan 2007, Naturskyddsföreningen
www.synchrotron.vic.gov.au