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The deliming operation in leather processing is a drum/paddle or pit based operation where two main objectives are met:

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37-428: A bracer (or arm-guard ) is a strap or sheath, commonly made of leather , stone or plastic , that covers the ventral (inside) surface of an archer 's bow -holding arm. It protects the archer's forearm against injury by accidental whipping from the bowstring or the fletching of the arrow while shooting , and also prevents the loose sleeve from catching the bowstring. They normally only cover part of

74-420: A drying and softening operation, and may include splitting, shaving, dyeing , whitening or other methods. For some leathers, tanners apply a surface coating, called "finishing". Finishing operations can include oiling, brushing, buffing, coating, polishing, embossing, glazing , or tumbling , among others. Leather can be oiled to improve its water resistance. This currying process after tanning supplements

111-432: A flexible form that does not become putrid when rewetted. Many tanning methods and materials exist. The typical process sees tanners load the hides into a drum and immerse them in a tank that contains the tanning "liquor". The hides soak while the drum slowly rotates about its axis, and the tanning liquor slowly penetrates through the full thickness of the hide. Once the process achieves even penetration, workers slowly raise

148-537: A form of bracer known as a ketoh , which can be decorated with silver, turquoise, and other adornments, possibly from earlier examples made of bone. Ketohs usually have a central motif, sometimes with a stone ornament, and four curvilinear shapes that radiate toward the corners. Ketohs may have a smooth leather surface on the inside of the arm and are then functional, but they are normally used as items of personal and ritual adornment, or as works of art in their own right. Stone wrist-guards from Beaker culture graves of

185-465: A general piece of armour rather than protective archery equipment, possibly due to confusion with vambraces . Leather Leather is a strong, flexible and durable material obtained from the tanning , or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle , sheep , goats, equine animals, buffalo, pigs and hogs, and aquatic animals such as seals and alligators. Leather can be used to make

222-642: A properly managed facility. A review of the total pollution load decrease achievable according to the United Nations Industrial Development Organization posts precise data on the abatement achievable through industrially proven low-waste advanced methods, while noting, "even though the chrome pollution load can be decreased by 94% on introducing advanced technologies, the minimum residual load 0.15 kg/t raw hide can still cause difficulties when using landfills and composting sludge from wastewater treatment on account of

259-430: A variety of items, including clothing, footwear, handbags, furniture, tools and sports equipment, and lasts for decades. Leather making has been practiced for more than 7,000 years and the leading producers of leather today are China and India. Critics of tanneries claim that they engage in unsustainable practices that pose health hazards to the people and the environment near them. The leather manufacturing process

296-628: A wet cloth or soaking the leather in water. Various treatments are available such as conditioners . Saddle soap is used for cleaning, conditioning, and softening leather. Leather shoes are widely conditioned with shoe polish . Due to its high resistance to abrasion and wind, leather found a use in rugged occupations. The enduring image of a cowboy in leather chaps gave way to the leather-jacketed and leather-helmeted aviator . When motorcycles were invented, some riders took to wearing heavy leather jackets to protect from road rash and wind blast; some also wear chaps or full leather pants to protect

333-416: Is a process that stabilizes the proteins , particularly collagen , of the raw hide to increase the thermal, chemical and microbiological stability of the hides and skins, making it suitable for a wide variety of end applications. The principal difference between raw and tanned hides is that raw hides dry out to form a hard, inflexible material that, when rewetted, will putrefy , while tanned material dries to

370-534: Is also used for falconry jesses, soccer footwear, (e.g. Adidas Copa Mundial ) and boxing speed bags. Although originally raised for their feathers in the 19th century, ostriches are now more popular for both meat and leather. Ostrich leather has a characteristic "goose bump" look because of the large follicles where the feathers grew. Different processes produce different finishes for many applications, including upholstery, footwear, automotive products, accessories, and clothing. In Thailand , stingray leather

407-411: Is called bating. Lipases are used in the degreasing operation to hydrolyze fat particles embedded in the skin. Amylases are used to soften skin, to bring out the grain, and to impart strength and flexibility to the skin. These enzymes are rarely used. The natural fibers of leather break down with the passage of time. Acidic leathers are particularly vulnerable to red rot , which causes powdering of

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444-405: Is divided into three fundamental subprocesses: preparatory stages, tanning, and crusting. A further subprocess, finishing, can be added into the leather process sequence, but not all leathers receive finishing. The preparatory stages are when the hide is prepared for tanning. Preparatory stages may include soaking, hair removal, liming , deliming , bating , bleaching , and pickling . Tanning

481-452: Is one of the most exploited reptile species in the world in the leather trade. However, it is not endangered and while monitored, trade is legal in most South American countries. Kangaroo leather is used to make items that must be strong and flexible. It is the material most commonly used in bullwhips . Some motorcyclists favor kangaroo leather for motorcycle leathers because of its light weight and abrasion resistance. Kangaroo leather

518-545: Is used in wallets and belts. Stingray leather is tough and durable. The leather is often dyed black and covered with tiny round bumps in the natural pattern of the back ridge of an animal. These bumps are then usually dyed white to highlight the decoration. Stingray rawhide is also used as grips on Chinese swords, Scottish basket hilted swords, and Japanese katanas . Stingray leather is also used for high abrasion areas in motorcycle racing leathers (especially in gloves, where its high abrasion resistance helps prevent wear through in

555-589: The 1970s and 80s) are well known for wearing leather clothing. Extreme metal bands (especially black metal bands) and Goth rock groups have extensive black leather clothing. Leather has become less common in the punk community over the last three decades, as there is opposition to the use of leather from punks who support animal rights . Many cars and trucks come with optional or standard leather or "leather faced" seating. In countries with significant populations of individuals observing religions which place restrictions on material choices, vendors typically clarify

592-528: The 20th century. Ammonium sulfate and ammonium chloride can be used as deliming agents and they follow the following chemistry: The ammonium ion is then free to penetrate the pelt cross-section and further ionise to act as an acid: The protons can then serve two functions, namely to protonate basic groups of the collagen and neutralize solution alkali chemicals. Other weak acids can be used such as boric acid , acetic acid , formic acid , lactic acid , phosphoric acid and carbonic acid . Carbonic acid

629-561: The European Bronze Age have been thought to be archery bracers. However, they are usually found on the outside of the arm where they would have been more conspicuous. Many have only two holes which would make them difficult to fasten securely to the arm, and some have projecting rivets which would catch on the bow string and make them unsuitable for use as a bracer. Many show great skill in polishing and stone working, and few are found in areas from which their stone originates. When

666-400: The alkaline phase of beamhouse operations . The progress of deliming in pelts is monitored by the checking of pH values of process liquors and in the cutting of a pelt cross-section. Phenolphthalein is used to monitor deliming pelt cross-sectional progress. The deliming process can be done with acids that can be rapid in their pH adjustment. Buffering salts like ammonium salts predominated

703-679: The event of an accident). For a given thickness, fish leather is typically much stronger due to its criss-crossed fibers. Leather produces some environmental impact, most notably due to: Estimates of the carbon footprint of bovine leather range from 65 to 150 kg of CO 2 equivalent per square meter of production. One ton of hide or skin generally produces 20 to 80 m of waste water, including chromium levels of 100–400 mg/L, sulfide levels of 200–800 mg/L, high levels of fat and other solid wastes, and notable pathogen contamination. Producers often add pesticides to protect hides during transport. With solid wastes representing up to 70% of

740-452: The following grades: The term "genuine leather" does not describe a specific grade. The term often indicates split leather that has been extensively processed, and some sources describe it as synonymous with bicast leather, or made from multiple splits glued together and coated. In some countries, when it is the description on a product label the term means nothing more than "contains leather"; depending on jurisdiction, regulations limit

777-436: The forearm, but full-length bracers extending to the upper arm are also available, and other areas have been covered by some archers. In addition, chest guards are sometimes worn, usually by female archers, to protect the breast . With some combinations of non-baggy clothing and bows with a larger distance between the bow and the string, the archer may not need to wear any bracer. The modern Navajo people and Hopi developed

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814-440: The leather. Chemical damage can also occur from exposure to environmental factors, including ultraviolet light, ozone, acid from sulfurous and nitrous pollutants in the air, or through a chemical action following any treatment with tallow or oil compounds. Both oxidation and chemical damage occur faster at higher temperatures. There are few methods to maintain and clean leather goods properly such as using damp cloth and avoid using

851-399: The liquor's pH in a process called basification, which fixes the tanning material to the leather. The more tanning material fixed, the higher the leather's hydrothermal stability and shrinkage temperature resistance. Crusting is a process that thins and lubricates leather. It often includes a coloring operation. Chemicals added during crusting must be fixed in place. Crusting culminates with

888-480: The lower body. Leather's flexibility allows it to be formed and shaped into balls and protective gear. Subsequently, many sports use equipment made with leather, such as baseball gloves and the ball used in cricket and gridiron football . Leather fetishism is the name popularly used to describe a fetishistic attraction to people wearing leather, or in certain cases, to the garments themselves. Many rock groups (particularly heavy metal and punk groups in

925-400: The natural oils remaining in the leather itself, which can be washed out through repeated exposure to water. Frequent oiling of leather, with mink oil , neatsfoot oil , or a similar material keeps it supple and improves its lifespan dramatically. Tanning processes largely differ in which chemicals are used in the tanning liquor. Some common types include: In general, leather is produced in

962-746: The objects occur in barrows , they always occur in the central primary grave, a place thought to be reserved for heads of family and other important people. They may have been status symbols of prowess in hunting or war, probably mounted as decorations on functional bracers. A few wrist-guards made of gold or amber have also been found; scholars believe these were for ornamental rather than functional use. A review identifies two major sources of stone from which they are made, suggests that they may well not be connected with archery, and highlights other potential uses. Bracers have also been used in other sports, including ball games such as Follis (played in ancient Rome ). In many common role-playing games , bracers are

999-538: The regulations currently in force in some countries." In Kanpur , the self-proclaimed "Leather City of World"—with 10,000 tanneries as of 2011 and a city of three million on the banks of the Ganges —pollution levels were so high, that despite an industry crisis, the pollution control board decided to shut down 49 high-polluting tanneries out of 404 in July 2009. In 2003 for instance, the main tanneries' effluent disposal unit

1036-468: The shell. It is prized for its mirror-like finish and anti-creasing properties. Lamb and deerskin are used for soft leather in more expensive apparel. Deerskin is widely used in work gloves and indoor shoes. Reptilian skins, such as alligator , crocodile, and snake , are noted for their distinct patterns that reflect the scales of their species. This has led to hunting and farming of these species in part for their skins. The Argentine black and white tegu

1073-542: The source of leather in their products. Such labeling helps facilitate religious observance, so, for example, a Muslim will not accidentally purchase pigskin or a Hindu can avoid cattleskin. Such taboos increase the demand for religiously neutral leathers such as ostrich and deer . Judaism forbids the comfort of wearing leather shoes on Yom Kippur , Tisha B'Av , and during mourning. Also, see Leather in Judaism , Teffilin and Torah Scroll . Jainism prohibits

1110-400: The surface and a change in consistency. Damage from red rot is aggravated by high temperatures and relative humidities. Although it is chemically irreversible, treatments can add handling strength and prevent disintegration of red rotted leather. Exposure to long periods of low relative humidities (below 40%) can cause leather to become desiccated, irreversibly changing the fibrous structure of

1147-440: The term's use in product labelling. Today, most leather is made of cattle (cow) hides, which constitute about 65% of all leather produced. Other animals that are used include sheep (about 13%), goats (about 11%), and pigs (about 10%). Obtaining accurate figures from around the world is difficult, especially for areas where the skin may be eaten. There are significant regional differences in leather production: i.e. goat leather

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1184-734: The use of leather, since it is obtained by killing animals. Many forms of artificial leather have been developed, usually involving polyurethane or vinyl coatings applied to a cloth backing. Many names and brands for such artificial leathers exist, including "pleather", a portmanteau of "plastic leather", and the brand name Naugahyde . Another alternative is cultured leather which is lab-grown using cell-culture methods, mushroom-based materials and gelatin-based textile made by upcycling meat industry waste. Leather made of fungi or mushroom-based materials are completely biodegradable. Deliming Deliming operations of cattle hides usually last two hours and are generally associated with

1221-462: The weekend of 8 April 2017 in the neighborhood. The higher cost associated with the treatment of effluents than to untreated effluent discharging leads to illegal dumping to save on costs. For instance, in Croatia in 2001, proper pollution abatement cost US$ 70–100 per ton of raw hides processed against $ 43/t for irresponsible behavior. In November 2009, one of Uganda's main leather making companies

1258-728: The wet weight of the original hides, the tanning process represents a considerable strain on water treatment installations. Leather biodegrades slowly—taking 25 to 40 years to decompose . However, vinyl and petrochemical-derived materials take 500 or more years to decompose. Tanning is especially polluting in countries where environmental regulations are lax, such as in India, the world's third-largest producer and exporter of leather. To give an example of an efficient pollution prevention system, chromium loads per produced tonne are generally abated from 8 kg to 1.5 kg. VOC emissions are typically reduced from 30 kg/t to 2 kg/t in

1295-544: Was caught directly dumping waste water into a wetland adjacent to Lake Victoria . Enzymes like proteases , lipases , and amylases have an important role in the soaking, dehairing, degreasing, and bating operations of leather manufacturing. Proteases are the most commonly used enzymes in leather production. The enzyme must not damage or dissolve collagen or keratin , but should hydrolyze casein , elastin , albumin , globulin -like proteins, and nonstructural proteins that are not essential for leather making. This process

1332-592: Was dumping 22 tonnes of chromium-laden solid waste per day in the open. In the Hazaribagh neighborhood of Dhaka in Bangladesh , chemicals from tanneries end up in Dhaka's main river. Besides the environmental damage, the health of both local factory workers and the end consumer is also negatively affected. After approximately 15 years of ignoring high court rulings, the government shut down more than 100 tanneries

1369-557: Was historically called "Turkey" or "Morocco" due to its association with the Middle East, while pig skin had historically been used the most in Germany. Other animals mentioned below only constitute a fraction of a percent of total leather production. Horse hides are used to make particularly durable leathers. Shell cordovan is a horse leather made not from the outer skin but from an under layer, found only in equine species, called

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