Leather is mainly divided into leather, bonded leather and artificial leather.A, leather. Leather are cattle, sheep, pigs, horses, deer, or some other animals off the original skin, after the tanneries tanning process, made from a variety of features, strength and handle the leather material, colour, decorative pattern, is a necessary ingredient for the modern leather products. Among them, cowhide, sheepskin and pigskin is three large leather tanning materials. Leather is divided into head layer and layer leather.Is 1, the first layer of leather with a grain of cattle, sheep, pig, etc., of the leather has a natural scar and blood muscle scar, etc., and occasionally the cuts in the process of machining and low utilization rate of the belly of parts, import of head skin and the serial number of the cattle. All full grain can distinguish from the thickness and pore density belong to what kind of animal leather. Cowhide sort is more, such as cow leather, cattle leather, leather, cowhide, grazing oxen, not castrated bull leather and castrated bull leather. In our country and cow hide, buffalo hide, yak leather and zho leather, etc. Among them, the buffalo hide the pores of the thick and thin; Cow leather is a buffalo hide pore thin and thick. Skin pores are more fine more tight and a bit of a slope, there are mainly two types: sheep skins and goat. Pigskin for hairy a handful of distribution rule is 3 ~ 5 root, so easy to distinguish, general multi-purpose captivity of pigskin, and wild boar, famous South American wild boar, this kind of wild boar is of obvious pig skin pores and grain characteristics of collagen fibers because of its special structure, can be processed into a very soft leather garment leather or gloves, a high value. In addition, the ostrich leather, crocodile skin, short nose crocodile, lizard, snake skin, bullfrog leather, seawater fish skin, fresh water fish skin, fox, Wolf of hairy skin, dogskin, rabbit skin is easy to recognize, and cannot be made on the second floor.Head skin is processed directly from the original skin of various animals, or the thicker cortex of animals such as cows, pigs, horses skin after hair removal cut into two layers, the upper part of the fibrous tissue closely is processed into a variety of head skin.2, second floor leather is second part of the fibrous tissue is loose, chemical material spraying or covering, PVC, PU film.Therefore, to distinguish the first layer of skin and skin effective method, on the second floor is to observe the longitudinal section of skin fiber density. By head skin is thick and thin fiber layer and closely together slightly loose transition layer composed of, with good technology of strength, elasticity and plasticity, etc. 2 are only loose skin layer of fibrous tissue, only after spraying chemical raw materials or polishing can used to make leather products, it keeps its natural elasticity and the characteristics of the technology of plasticity, but strength is poorer, its thickness requirements as well as the head skin. And used in the popular production of all kinds of leather, leather processing technology a little different, but to distinguish method.Second, bonded leather, bonded leather will all kinds of animal fee leather and leather scraps, after mixing chemical raw materials processing. The surface processing technology, like real leather face, embossed leather, its characteristic is the skin edges is neat, high efficiency, low-cost; Usually thicker, but skin body strength is poorer, briefcase, rod bags, only suitable for making parity clubs set of products and finalize the design process, such as parity belt, the longitudinal section fibrous tissue uniform, distinguishable recognize liquid solidification effect of hybrid fiber.Three, artificial leather, bonded leather or imitation leather or rubber, is the floorboard of the synthetic materials such as PVC and PU. It is on the textile duct or non-woven base, by all sorts of different formulations of PVC and PU foam or coated processing, can according to the different strength, wear-resisting, cold resistant degrees and color, luster and pattern request processing is made, with a wide variety of design and color, good waterproof performance, keep out appearance neat, high utilization rate and the price relative to the characteristics of the leather is cheap, but the vast majority of artificial leather, its handle and elastic cannot achieve the result of leather; Its longitudinal section, you can see the tiny air bubbles hole, duct, or surface layer of thin film and dry dry artificial fibers. It is early until now very popular a kind of material, is widely used to make all kinds of leather goods, or part of the leather materials. It is becoming more and more advanced production technology, are are widely used in second floor leather processing production.