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Leather
Leather is a strong, flexible and durable material obtained from the tanning (leather), 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, ostriches, and aquatic animals such as seals and alligators. Leather can be used to make 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. Production processes The leather manufacturing process 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leather Tanning, Fes
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, ostriches, and aquatic animals such as seals and alligators. Leather can be used to make 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. Production processes The leather manufacturing process 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Whitening (leather Processing)
The leather manufacturing process are the operations taken to create leather from Hide (skin), hides. The procedure is divided into three sub-processes: preparatory stages, Tanning (leather), tanning, and crusting. All true leathers will undergo these sub-processes. A further sub-process, surface coating, may be added into the sequence. The list of operations that leathers undergo vary with the type of leather. There are environmental impacts associated with the process. Sub-processes Preparatory stages The preparatory stages are when the Hide (skin), hide is prepared for Tanning (leather), tanning. During the preparatory stages many of the unwanted raw skin components are removed. Many options for pretreatment of the skin exist. Not all of the options may be performed. Preparatory stages may include: * preservation- the hide is treated with a method which renders it temporarily imputrescible. * Tanning (leather)#Soaking, soaking - water for purposes of washing or rehydratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanning (leather)
Tanning, or hide tanning, is the process of treating Skinning, skins and Hide (skin), hides of animals to produce leather. A tannery is the place where the skins are processed. Historically, vegetable based tanning used tannin, an acidic chemical compound derived from the bark of certain trees, in the production of leather. An alternative method, developed in the 1800s, is chrome tanning, where chromium salts are used instead of natural tannins. History Tanning hide into leather involves a process which permanently alters the protein structure of skin, making it more durable and less susceptible to decomposition and coloring. The place where hides are processed is known as a ''tannery''. The English word for tanning is from the medieval Latin verb , from the noun (oak bark). This term may be derived from a Celtic word related to the Proto-Indo-European *' meaning 'fir tree'. (The same root is the source for Old High German meaning 'fir', related to modern German ''Tannenb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bating (leather)
Bating is a technical term used in the Tanning (leather), tanning industry to denote leather that has been treated with chicken, hen or pigeon manure, similar to ''puering'' (see wiktionary:puer, puer) where the leather has been treated with dog excrement, and which treatment, in both cases, was performed on the raw hide prior to tanning in order to render the skins, and the subsequent leather, soft and supple. Today, both practices are obsolete and have been replaced in the tanneries with other natural proteolytic enzymes. Leather processing Since early times, tanners have made use of either dog fæces, or hen and pigeon manure, in one of the early phases of leather treatment to produce a soft leather. A bath solution containing the animal extracts was made and the raw hide inserted and left there for a few days, which activated the bacteria and enzymes that reacted with the collagen in the animal skin to make the leather soft and supple. This step was followed by ''drenching'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boiled Leather
Boiled leather, often referred to by its French translation, cuir bouilli (), was a historical material common in the Middle Ages and Early Modern Period and used for various purposes. It was leather that had been treated so that it became tough and rigid, as well as able to hold moulded decoration. It was the usual material for the robust carrying-cases that were made for important pieces of metalwork, instruments such as astrolabes, personal sets of cutlery, books, pens and the like. It was used for some armour, being both much cheaper and much lighter than plate armour, but could not withstand a direct blow from a blade, nor a gunshot. Alternative names are "moulded leather" and "hardened leather". In the course of making the material it becomes very soft, and can be impressed into a mould to give it the desired shape and decoration, which most surviving examples have. Pieces such as chests and coffers also usually have a wooden inner core. Various recipes for making cuir bouil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neatsfoot Oil
Neatsfoot oil is a yellow oil rendered and purified from the shin bones and feet (but not the hooves) of cattle. "Neat" in the oil's name comes from an Old English word for cattle. Neatsfoot oil is used as a conditioning, softening and preservative agent for leather. In the 18th century, it was also used medicinally as a topical application for dry scaly skin conditions. Despite its name, "prime neatsfoot oil" (or "neatsfoot oil compound") is a blend of actual neatsfoot oil and non-animal oils, generally mineral or other petroleum-based oils. Characteristics Fat from warm-blooded animals normally has a high melting point, becoming hard when cool, but neatsfoot oil remains liquid at room temperature. This is because the relatively slender legs and feet of animals such as cattle are adapted to tolerate and maintain much lower temperatures than that of the body core, using countercurrent heat exchange in the legs between warm arterial and cooler venous blood. Other body ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and Precipitation (chemistry), precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' is widely applied to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups (such as carboxyls) to form strong complexes with various macromolecules. The term ''tannin'' (from scientific French ''tannin'', from French ''tan'' "crushed oak bark", ''tanner'' "to tan", cognate with English language, English ''tanning'', Medieval Latin ''tannare'', from Proto-Celtic ''*tannos'' "oak") refers to the abundance of these compounds in oak Bark (botany), bark, which was used in Tanning (leather), tanning animal Hide (skin), hides into leather. The tannin compounds are widely distributed in many species of plants, where they play a role in protection from predation (acting as pesticides) and might help in regulating plant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cattle
Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are called cows and mature male cattle are bulls. Young female cattle are called heifers, young male cattle are oxen or bullocks, and castrated male cattle are known as steers. Cattle are commonly raised for meat, for dairy products, and for leather. As draft animals, they pull carts and farm implements. Cattle are considered sacred animals within Hinduism, and it is illegal to kill them in some Indian states. Small breeds such as the miniature Zebu are kept as pets. Taurine cattle are widely distributed across Europe and temperate areas of Asia, the Americas, and Australia. Zebus are found mainly in India and tropical areas of Asia, America, and Australia. Sanga cattle are found primarily in sub-Saharan Africa. These types, sometime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanbark
Tanbark is the Bark (botany), bark of certain species of trees, traditionally used for Tanning (leather), tanning Hide (skin), hides into leather. The words "tannin", "Tanning (leather), tanning", "Tan (color), tan," and "Tawny (color), tawny" are derived from the Medieval Latin , "to convert into leather." Bark mills are horse- or oxen-driven or water-powered edge mills and were used in earlier times to shred the tanbark to derive tannins for the leather industry. A "barker" was a person who stripped bark from trees to supply bark mills. Tanbark around the world In Europe, oak is a common source of tanbark. Quercitannic acid is the chief constituent found in oak barks. The bark is taken from young branches and twigs in oak coppices and can be up to 4 mm thick; it is grayish-brown on the outside and brownish-red on the inner surface. In some areas of the United States, such as central Pennsylvania and northern California, "mulch" is often called tanbark, even by manufactu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liming (leather Processing)
Liming is a process used for parchment or leather processing, in which hides are soaked in an alkali solution. It is performed using a drum and paddle or a pit. Its objectives are: * Removal of interfibrillary proteins. * Removal of keratin proteins. * Collagen swelling due to the alkaline pH. * Collagen fibre bundle splitting. * Removal of natural grease and fatsS.S. Dutta, ''An Introduction to the Principles of Leather Manufacture'', p. 160 Liming operations of cattle hides usually last 18 hours and are generally associated with the alkaline phase of beamhouse operations. Removal of interfibrillary proteins The interfibrillary proteins are denatured by the presence of alkali (particularly sodium sulfide), rendered soluble, facilitating their removal from the leather. Removal is done by the mechanical action of liming or reliming, but more prominently when the pelt is deswelled (during deliming). Failure to remove these proteins results in a hard, tinny leather (due to fibre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Collagen
Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a triple helix of elongated fibril known as a collagen helix. It is mostly found in cartilage, bones, tendons, ligaments, and skin. Vitamin C is vital for collagen synthesis. Depending on the degree of biomineralization, mineralization, collagen tissues may be rigid (bone) or compliant (tendon) or have a gradient from rigid to compliant (cartilage). Collagen is also abundant in corneas, blood vessels, the Gut (anatomy), gut, intervertebral discs, and the dentin in teeth. In muscle tissue, it serves as a major component of the endomysium. Collagen constitutes 1% to 2% of muscle tissue and 6% by weight of skeletal muscle. The fibroblast is the most common cell creating collagen in animals. Gelatin, which is used in food and industry, is collagen t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
