Leather, natural synthetic

Natural leather is produced from the hides of animals by cross-linking the collagen protein contained in the hide. On the other hand, synthetic leathers are synthetic polymer composites with leatherlike properties. 

Leather-like materials now important in the market are of three main classes (/) vinyl-coated fabrics, (2) urethane-coated (synthetic) fabrics, and (J) man-made leathers. To appreciate their leather-replacement capabiUties it is necessary to know the stmcture of natural leather. 

Phthalocyanine Dyes. In addition to their use as pigments, the phthalocyanines have found widespread appHcation as dyestuffs, eg, direct and reactive dyes, water-soluble dyes with physical or chemical binding, solvent-soluble dyes with physical or chemical binding, a2o reactive dyes, a2o nonreactive dyes, sulfur dyes, and wet dyes. The first phthalocyanine dyes were used in the early 1930s to dye textiles like cotton (qv). The water-soluble forms Hke sodium salts of copper phthalocyanine disulfonic acid. Direct Blue 86 [1330-38-7] (Cl 74180), Direct Blue 87 [1330-39-8] (Cl 74200), Acid Blue 249 [36485-85-5] (Cl 74220), and their derivatives are used to dye natural and synthetic textiles (qv), paper, and leather (qv). The sodium salt of cobalt phthalocyanine, ie. Vat Blue 29 [1328-50-3] (Cl 74140) is mostly appHed to ceUulose fibers (qv). 

Non-metallic Materials Carbides, carbon, ceramic fiber, ceramic, cermet, composite, cork, elastomer, felt, fiber, glass, glycerin, non-metallic bearing material, rubber (natural), rubber (synthetic), silicone, wood, leather. 

Uses Manufacture of artificial leathers, plastics, safety glass, photographic films, lacquers as a solvent in the production of perfumes, natural gums, and synthetic resins solvent for nitrocellulose lacquers dehydrating agent. 

Uses Solvent for natural and synthetic resins, cellulose acetate, nitrocellulose, and some dyes nail polishes dyeing leather sealing moisture-proof cellophane lacquers, varnishes, enamels, wood stains in solvent mixtures perfume fixative jet fuel de-icing additive. 

POROMER1C. A term coined to describe the microporosity, air permeability, and water and abrasion resistance of natural and synthetic leather. The pores decrease in diameter from the inner surface to the outer and thus permit air and water vapor lo leave lire material while excluding water from the outside. Polyester-reinforced urethane resins have been used as leather substitutes with some success, primarily for shoe uppers. 

Many of the synthetic materials are not just substitutes for scarce natural materials. They are also competitors of materials like wool, silk, cotton, leather and rubber. 

The use of both natural and synthetic mordant dyes has long passed its zenith. Synthetic mordant dyes are still listed as leather dyes in the Colour Index. These are chiefly monoazo dyes, which are used especially for prechromed wool. For leather, the operations involved in the metallization step are too complex and time-consuming. Nowadays, modem tanneries prefer premetallized dyes. 

As a matter of fact, mankind knows polymers from ancient times, due to the existence of naturally occurring polymers such as latex, starches, cotton, wool, leather, silk, amber, proteins, enzymes, starches, cellulose, lignin, and others. The other type of polymers are synthetic polymers. Braconnot, in 1811, perhaps made the first significant contribution to polymer science by developing compounds derived from cellulose. Later, cellulose nitrate was obtained in 1846 by Schonbein, afterward in 1872, its industrial production was established. Besides, in 1839, Goodyear found out by accident that by heating latex with sulfur its properties were altered creating a flexible and temperature-stable rubber. This process is named vulcanization. 

Very attractive finishes can be obtained from rollers formed by electrodeposition of nickel, including leather, textiles, and other natural and synthetic textures. This method allows the faithful reproduction of a finish across the full width of the cylinder and, since undercuts cannot be achieved by the milling process, gives a more realistic appearance in (as an example) woven designs. 

We now well appreciate, of course, that polymers are virtually everywhere. Some of them occur naturally, and we continue to better understand their compositions, structures, and properties. Many of these materials have been used since the dawn of human existence, for food, obviously. Cellulose alone has been essential for clothing, fire, shelter, tools, weapons, writing, and art. Leather is probably the result of the first synthetic polymer reaction, essentially the crosslinking of protein (elastin). How we progressed over time to the Polymer Age is a fascinating series of stories, some of which are well worth recounting here. 

So when did polymer science begin The answer is not easy to determine, so it will help to attempt to understand why. Let s try to imagine our world without synthetic polymers. Our clothing would consist entirely of cotton, wool, linen, and, if we could afford it, silk. Our shoes would be made of leather. Raincoats would consist of cotton coated with natural rubber. Automobiles would be considerably heavier because they would be made mostly of steel, glass, and natural rubber. Their interiors would be covered in leather. 

Use and exposure There are three forms of xylene meto-xylene, ortho-xyltnt, and para-xylene (m-, o-, and p-xylene). These different forms are referred to as isomers. Xylene is a colorless, sweet-smelling liquid that catches tire easily. It occurs naturally in petroleum and coal tar. Chemical industries produce xylene from petroleum. Xylene is used as a solvent in the printing, rubber, and leather industries. It is also used as a cleaning agent, a thinner for paint, and in paints and varnishes. It is found in small amounts in airplane fuel and gasoline. Xylene is used extensively in the manufacture of many other chemicals, such as plastics, synthetic fibers, pesticides, insect repellents, and leather goods. ... 

Dyes are used primarily to impart color in textile, leather, paints, cosmetic, and food industries. Many natural dyes (animal, mineral, or vegetal extracts) have been largely replaced by synthetic dyes that were developed at the end of the nineteenth century. Dyes should be safe, with no toxicity, carcinogenicity, or... 

Use Solvent for nitrocellulose, natural and synthetic resins mutual solvent for formulation of soluble oils lacquers and lacquer thinners dyeing and printing textiles varnish removers cleaning solutions leather antiicing additive for aviation fuels. 

Use Solvent for nitrocellulose, cellulose acetate, alcohol-soluble dyes, natural and synthetic resins, solvent mixtures, lacquers, enamels, varnishes, leather perfume fixative wood stains sealing moisture-proof cellophane jet fuel deicing additive. 

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