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Comment
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J Jaws
Mar 19, 08 - 5:46 AM |
Industrija koze
Industrija koze i zagadjenje okoline:
Influence of the Leather Industry on the Pollution of Coastal Sediments by Chromium in the Zadar Area (Eastern Adriatic) Hrčak -Portal of scientific journals of Croatia
China Leather Industry Association report The CLIA reported this week that China imported $5.6 billion worth of hides and skins in 2006, or 15.38% more than in 2005. They also said that they exported $12.4 billion in leather products. This was 8.8% more than the 2005 figure.
Industrija koze- Taiwan (pdf.)
The leather tanning industry in Taiwan is a significantsource of pollution.
(ovo je izvestaj od industrijalaca- i sami pominju koliki je problem zagadjenje od strane industrije koze)
Microbial enzyme technology as an alternative to conventional chemicals in leather industry Leather industry contributes to one of the major industrial pollution problems facing the country, and the pollution causing chemicals, viz. lime, sodium sulphide, salt, solvents, etc. arise mainly from the pre-tanning processes of leather processing.
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J Jaws
Mar 19th, 2008 - 5:51 AM |
Re: Industrija koze
Asia news: Pollution: Fujian farmers destroy machines of 11 factories
A Quangang district official said the violence was triggered by local officials' failure over the past few years to monitor the leather industry's compliance with environmental standards.
Cruelty to Animals Forces U.S. Retailer to Boycott India Leather; Industry Dismayed
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J Jaws
Mar 19th, 2008 - 6:01 AM |
Re: Industrija koze
Industrija koze, postupak pretvaranja u "proizvod" (hemikalije i prerada):
...As with all pollution control, the costs are high... (pdf.)
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J Jaws
Oct 31st, 2008 - 2:24 PM |
Re: Industrija koze
Hong Kong Fur Industry and Exports
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J Jaws
Oct 31st, 2008 - 2:28 PM |
Re: Industrija koze
malo i o krznu:
Environmental Devistation
Nothing Natural about Fur
In the face of causing such notorious, unnecessary cruelty to animals, furriers desperate for positive things to say about their product often resort to the claim that furs are “natural.” In fact, turning an animal’s skin into a coat involves preserving it with toxic chemicals, such as formaldehyde—a known carcinogen—in order to keep the carcass from decaying.
Furriers also claim that fur trapping is a necessary tool for wildlife management. However, trapping as a commercial enterprise can never be a wildlife management strategy. Proper wildlife management needs to be based on highly specific local circumstances, recognizing the delicate balance of a particular ecosystem. But the book "Fur Trapping: A Complete Guide" shows the true motivator for trapping—money. "The trapper should trap the fur most in demand. If bobcats bring a high of $400, as they did in 1976, he should concentrate on them." Is this wildlife management—or slaughter for profit? Wildlife populations follow natural fluctuation curves. Unchecked hunting and trapping of certain animals have disrupted these fluctuations. The furriers’ and trappers’ scientifically baseless claim that they are “managing” wildlife is a thinly disguised ploy to kill the most profitable animals.
Once a symbol of glamour and success, fur is now a symbol of insensitivity, vanity, and greed. World-famous designers such as Giorgio Armani, Stella McCartney, Donna Karan, Geoffrey Beene and Calvin Klein now refuse to include fur in their collections. Leading retailers including Harrods of London and I. Magnin have stopped selling furs altogether.
Each of us can make the compassionate choice to not support such unnecessary cruelty to animals and to speak out on the animals’ behalf.
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J Jaws
Oct 31st, 2008 - 2:32 PM |
Re: Industrija koze
Leather is a material created through the tanning of hides and skins of animals, primarily cattlehide. The tanning process converts the putrescible skin into a durable, long-lasting and versatile natural material for various uses.
Together with wood, leather formed the basis of much ancient technology. The leather industry and the fur industry are distinct industries that are differentiated by the importance of their raw materials. In the leather industry the raw materials are by-products of the meat industry, with the meat having higher value than the skin. The fur industry uses raw materials that are higher in value than the meat and hence the meat is classified as a by-product. Taxidermy also makes use of the skin of animals, but generally the head and part of the back are used. Hides and skins are also used in the manufacture of glue and gelatin.
Preservation and conditioning of leather
Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and other salts of chromium. It is more supple and pliable than vegetable-tanned leather, and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium. More esoteric colors are possible using chrome tanning.
Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds. This is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the main type of leather used in chrome-free leather often seen in infant's shoes and in automobiles made with chrome-free leather. Formaldehyde tanning (being phased out due to its danger to workers and the sensitivity of many people to formaldehyde) is another method of aldehyde tanning. Brain-tanned leathers fall into this category and are exceptionally water absorbent. Brain tanned leathers are made by a labor-intensive process which uses emulsified oils, often those of animal brains. They are known for their exceptional softness and their ability to be washed. Chamois leather also falls into the category of aldehyde tanning and like brain tanning produces a highly water absorbent leather. Chamois leather is made by using oils (traditionally cod oil) that oxidise easily to produce the aldehydes that tan the leather.
Synthetic-tanned leather is tanned using aromatic polymers such as the Novolac or Neradol types. This leather is white in color and was invented when vegetable tannins were in short supply, i.e. during the Second World War. Melamine and other amino-functional resins fall into this category as well and they provide the filling that modern leathers often require. Urea-formaldehyde resins were also used in this tanning method until dissatisfaction about the formation of free formaldehyde was realised.
Alum-tanned leather is tanned using aluminium salts mixed with a variety of binders and protein sources, such as flour, egg yolk, etc. Purists argue that alum-tanned leather is technically "tawed" and not tanned, as the resulting material will rot in water. Very light shades of leather are possible using this process, but the resulting material is not as supple as vegetable-tanned leather.
Rawhide is made by scraping the skin thin, soaking it in lime, and then stretching it while it dries. Like alum-tanning, rawhide is not technically "leather", but is usually lumped in with the other forms. Rawhide is stiffer and more brittle than other forms of leather, and is primarily found in uses such as drum heads where it does not need to flex significantly; it is also cut up into cords for use in lacing or stitching, or for making many varieties of dog chews.
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J Jaws
Oct 31st, 2008 - 2:37 PM |
Re: Industrija koze
How is a leather jacket made?
Trimming and cleaning
The skins are trimmed and sorted according to size, weight, and thickness. It is necessary to remove any remaining proteins that could stimulate the growth of bacteria. To this end, the skins are soaked in revolving drums filled with water, bactericides, and detergents. Hair is removed with the application of chemical sprays or lime solutions. A scudding machine fitted with dull blades scrapes off any excess hair.
Another round of washing (de-liming) removes these chemicals before the hides are soaked in an acid solution and then bated, an enzyme treatment to further remove the skins' collagens. Finally, the hides are pickled with salt and sulfuric acid.
Tanning
The hides undergo one of three types of tanning. Vegetable tanning requires the most time with the skins soaked in progressively stronger tannic acid solutions for several weeks. However, some soft leathers, such as lambskin, may be soaked for as little as 12 hours.
Mineral tanning is significantly faster but can change the color of the leather. For this method, the skins are placed in alum salt-filled drums fitted with paddles that provide a constant agitating motion.
The third method, oil tanning, is the one that resembles the ancient methods most closely. Here, fish oil is sprayed onto the skins.
Washing and drying
After the skins have been tanned, they are washed once again and wrung out thoroughly. Then the skins are passed under a band knife, which cuts the skins to a uniform thickness, and placed on conveyer belts which carry them to drying tunnels. Usually, the skins are stretched on frames to prevent shrinkage during the drying stage. To combat the stiffness that drying produces, the hides are sprayed with water and soap and allowed to hang for a period of time.
After the skins have been conditioned, they are placed in machines designed to rhythmically manipulate the leather so that the fibers are further loosened and made more flexible. In the final drying period, the hides are hung in vacuum-drying cabinets.
When the skins are thoroughly dried, they are buffed with revolving steel cylinders covered with abrasive paper. Suede finishes are produced by passing the hides under high-speed emery wheels. At this point, glazes, dyes, and lacquers are applied. The skins are now ready to be sent to the garment factory.
The Chemical Reporter - How is Leather Produced?
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