Leather
leather is the raw leather from cattle, sheep, pig, horse, deer or some other animals, which is tanned and processed by leather factory to make leather materials with various characteristics, strength, handle, color and pattern, which is the necessary material for modern leather products. Among them, cowhide, sheepskin and pigskin are three kinds of raw materials used in leather making. The dermis is divided into two types: the first skin and the second skin
(1) the head skin is a kind of cow, sheep and pig skin with grain surface. There are natural scars and blood veins on the skin surface. Occasionally, there are knife wounds in the process of processing and belly parts with extremely low utilization rate. The imported head skin also has the serial mark of cattle. Full grain leather can be distinguished from animal leather by pore size and density. There are many kinds of cattle hide, such as milk hide, meat hide, grazing hide, cow hide, Bull Hide, UN castrated bull hide and castrated bull hide. 1n China, there are also cattle hide, buffalo hide, Yak Hide and Yak Hide. Among them, the pores of buffalo skin are thicker and thinner; The pores of cattle hide were thinner and denser than those of buffalo hide. The pores of sheepskin are thinner, denser and a little inclined, mainly including sheepskin and goat skin. Pigskin is very easy to distinguish because the rule of long hair is 3-5 roots and a pinch of distribution. Generally, it is mostly used in artificial breeding pigskin and wild boar skin. The famous one is South American wild boar. This kind of wild boar skin has obvious characteristics of pores and grain size. Due to its special collagen fiber structure, it can be processed into very soft garment leather or glove leather with high value. 1n addition, ostrich skin, crocodile skin, short nose crocodile skin, lizard skin, snake skin, bullfrog skin, sea fish skin (including shark skin, cod skin, minnow skin, eel skin, pearl fish skin, etc.), freshwater fish skin (including grass carp skin, carp skin, etc.), fox skin with hair (silver fox skin, blue fox skin, etc.), wolf skin, dog skin, rabbit skin, etc. are easy to identify, and can not be made into two-layer skin
the head skin is directly processed from the original skins of various animals, or the thick skins of cattle, pigs, horses and other animals are dehaired and then cut into two layers horizontally, and the upper part with tight fibrous tissue is processed into various head skins
(2) the two-layer skin is a loose part of the fiber tissue, which is sprayed with chemical materials or coated with PVC and Pu films
therefore, the effective way to distinguish the first skin from the second skin is to observe the fiber density in the longitudinal section of the skin. The scalp is composed of a dense and thin fiber layer and a slightly loose transition layer closely connected with it, which has the characteristics of good strength, elasticity and process plasticity. The second skin has only loose fibrous tissue layer, which can only be used to make leather products after spraying chemical raw materials or polishing. 1t maintains a certain natural elasticity and process plasticity, but its strength is poor, and its thickness requirement is the same as that of the first skin. There are also various kinds of leather which are used in today’s popular production. The leather processing technology is different, but the differentiation method is the same
recycled skin
recycled skin is made by crushing waste skin and leather scraps of various animals and blending chemical raw materials. 1ts surface processing technology is the same as that of shaving leather and embossing leather, which is characterized by neat edges, high utilization rate and low price; However, the leather body is generally thick and the strength is poor, so it is only suitable for the production of low-cost official case, pull rod bag, ball rod cover and other shaped products and low-cost belt. The longitudinal section of the fiber structure is uniform, which can identify the solidification effect of fluid mixed fiber
artificial leather
recycled leather, also known as imitation leather or rubber, is the general name of PVC, PU and other artificial materials. 1t is made of PVC and Pu foamed or coated on the basis of textile or non-woven fabrics. 1t can be processed according to different strength, wear resistance, cold resistance, color, luster, pattern and other requirements. 1t has the characteristics of various colors, good water resistance, neat side width, high utilization rate and relatively low price, But most of the artificial leather, its handle and elasticity can not achieve the effect of leather; 1ts longitudinal section, you can see fine bubble holes, cloth or surface film and dry man-made fiber. 1t is a kind of material which is very popular from the early days until now. 1t is widely used to make all kinds of leather products, or some genuine leather materials. 1ts increasingly advanced manufacturing technology is widely used in the production of double skin
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