A method for rapid identification of dermis
1, smell it first. The smell of artificial leather is similar to the pungent smell of plastic. The taste of genuine leather is quite special. You can get some real leather to smell first.
2. Look at the ductility of leather. The dermis is soft and elastic. Artificial leather is much worse.
3, then look at the pores. Generally, most of the leather coats outside are sheepskin, and the appearance of sheepskin is relatively strong, which is easy to identify one by one. There are few cowhide clothes, so I don't know how to tell the truth from the false. The pores of artificial leather clothes are consistent, while the pores of leather are irregular.
Identification of genuine leather fabrics
1. First, check whether there are pores on the leather surface. Cowhide has fine pores, irregular arrangement and smooth leather; Pores of pigskin are arranged in a triangle, and the cortex is loose.
2. Then, when checking, you can use the indentation to see if there are any fine lines scattered in the indentation.
3. Second, check the edge of the cortex. Because the forgery technology is getting better and better now, it is more and more difficult to analyze it from the front. And some reasons can be seen from the cross section of cortex. The dermis is loose and the fake skin is tight.
4. Genuine leather and fake skin can also be distinguished by smell. Genuine leather obviously smells like animals, while artificial leather is relatively more irritating.
Dermal is made by peeling off the epidermis of animals and chemical treatment, while fake skin (mainly PU). PVC) is made of chemical fiber cloth after chemical treatment, and the difference between them lies in the different raw materials. However, due to the similar post-treatment methods, the surface effect is very close and it is difficult to distinguish, but there are many differences in internal physical properties. There is still a certain gap (but the gap is narrowing step by step) in physical strength, aging resistance and hand feel of genuine leather.
The reason why genuine leather is expensive lies in its natural and inherent physical properties and raw materials are not easy to obtain, while imitation leather has a market because of its price, surface effect changes and a crow's special physical properties. In some industries that pay attention to internal performance, such as shoemaking, clothing and real leather, it has advantages over artificial leather. However, in some industries that do not require high intrinsic performance, such as leather handbags, furniture and sofas, the market for imitation leather is relatively large. I don't approve of making shoes with fake leather and then making them with genuine leather brand, which makes them uncomfortable, airtight and easy to break.
There are many leather shoes on the market at present. In order to reduce the cost, some genuine leather and some imitation leather are generally made together, or two layers of plastic film are used instead of genuine leather (PU is used as a mask on the second layer of leather, which has poor air permeability). It shouldn't matter if it's not used in the main part. If the shoes are completely genuine leather, it is normal to use a better one without damage in the main parts and a less damaged one in some secondary parts (such as the tongue of shoes) because of the naturalness of genuine leather, which is also a good way to distinguish genuine leather from fake leather products. After all, you can't cut other people's shoes to see if there is suede! At the current market price, you can buy real leather shoes in most shoe stores in general cities above 150 yuan, but below this price, you are not in a regular shoe store. Be careful, especially those cheap goods sold by outdoor vendors. If you are not a professional, you should be careful. Don't be greedy for petty gains, 99% of them are lies. ) In regular shoe stores, 150 yuan can buy a pair of leather shoes with trimmed edges (that is, polished and heavily coated leather with poor air permeability), 150 yuan can buy a pair of full-grain shoes in 300 yuan, and a pair of high-grade shoes made of calf leather and other materials can be bought above 300 yuan. Of course, if you still want high-end, you can buy a pair of imported leather shoes.
In this industry, the amount of artificial leather is relatively large, as follows:
1。 Women's fashion shoes. Almost all of them are imitation leather, and the better ones will make shoes with a little genuine leather.
2。 Sports shoes (sneakers) are almost made of PU. PVC synthetic leather, wholesale Boss handbag, two-layer film is better, basically no top layer of leather.
3。 Leather handbags, using double-layer plastic film and fake leather mixed more.
4。 The belt is generally covered with two layers of film, and the imitation leather is easy to break.
How to correctly identify the way for buyers to buy leather shoes and hats
basic knowledge
Fabric products include: mohair cotton acrylic rayon yarn-dyed, tie-dyed and printed fabric Tencel linen wool cashmere alpaca wool blended knitted fabric silk.
Leather products include VC PU semi-PU leather fur, patterned leather printed fur, optical glue products, leather clothes, leather gloves, artificial fur and artificial suede.
Preliminary and simple identification method of 1. dermis
Touch: Touch the leather surface with your hands. If it feels smooth, soft, plump and elastic, it is genuine leather. However, synthetic leather is hard, stiff and has poor softness.
At first glance, we can see that the pores and patterns of leather are clear, while the pores of cowhide are well-proportioned and fine, the pores of yak skin are coarse and sparse, the pores of goatskin are fish scales, and the pores of pigskin are triangular and coarse. Although artificial leather also imitates pores, it is not clear.
Smell: All dermis has the smell of leather; Moreover, artificial leather has a strong plastic pungent smell.
Ignition: tear off a little fiber from the back of genuine leather and artificial leather. After ignition, it is artificial leather that emits a pungent smell and forms a knot. It's genuine leather that smells like hair without induration.
In addition, you can also drop water on leather and artificial leather for a period of time to make the leather feel absorbent; However, artificial leather doesn't. It just likes dew falling on leaves.
2. Advanced dermis identification method
A. Identifying artificial leather and synthetic leather
With the above four basic identification methods, it is obvious to compare and identify artificial leather and synthetic leather. In addition, artificial leather and synthetic leather have the following characteristics:
1. When leather is pressed with fingers, there are no obvious pores and wrinkles. If there are wrinkles after pressing, they will not disappear naturally.
2. There are no pores on the leather surface, which is an important feature to identify the authenticity of leather.
3, cut off the corners and burn, there is a taste, but it is not the smell of burning hair.
3. How to distinguish cowhide, pigskin, horse skin and sheepskin?
Different types of leather have different characteristics and uses. For example, cowhide has fine surface and high strength, which is most suitable for leather shoes and leather goods; Sheep leather is light and soft, which is an ideal fabric for making leather clothes. Pigskin has good air permeability and moisture permeability.
Pig skin: The pores on the skin surface are round and thick, and extend obliquely into the skin. The pores are arranged in groups of three, and the leather presents many small triangular patterns.
Cowhide: Cowhide and buffalo hide are both called cowhide, but there are some differences between them. The pores on the surface of cowhide are round and extend straight into the leather. Pores are compact and even, and arranged irregularly, like stars all over the sky. The pores on the surface of buffalo hide are thicker than those in cattle hide, the number of pores is less than that in cattle hide, and the leather is slack, which is not as detailed and plump as that in cattle hide.
Horse skin: the hair on the leather surface is also oval, slightly larger than the pores of cowhide, and arranged regularly.
Sheepskin: The pores on the grain surface of leather are flat and round, and the pores are clear. They form a group of several, arranged in fish scales.
Leather quality appraisal
Cowhide can be divided into multiple layers (up to 8 layers). The outermost layer is the first layer with the best quality, followed by the second layer, which is not as good as the first layer in strength, elasticity and air permeability. Car seats must use the first layer of leather. A kind of synthetic leather sold in the market now is to stick a layer of adhesive film on the surface of the second layer of leather, which looks like the first layer of leather and has a delicate surface. Some merchants pretend to be the first layer of skin to deceive users, so we should pay attention to identification.
From Ye Ying's point of view, the identification of leather should be judged from the smell, specific gravity, light resistance, migration resistance, atomization, thermal yellowing and friction resistance of automobile leather. Because most car owners have no professional knowledge in this field, it is difficult to judge. You might as well use the following simple methods to identify.
1), labeling method
The back of the leather in the factory will be marked with the date of production, the name and area of the leather factory, etc. Of course, the production date should not be too long, and the leather over 3 years should pay attention to whether there is mildew.
2), olfactory method
Good leather should not have pungent smell after treatment, too much solvent smell and paint smell are not good.
3), heat resistance method
It is best to ask the manufacturer for a small piece of leather and burn the sample with cigarette butts for about 2 ~ 3 seconds to avoid buying artificial leather products; Because of the large contact area, the burning time with a lighter needs to be increased.
4), viewing method
Under the magnifying glass of 30 times, we can see that leather is like the surface of the earth, with holes and good air permeability. Automobile leather needs special treatment such as wear resistance and light resistance, and pores will be covered.
5), cutting method
When cutting leather with a blade, the color of leather should be consistent from the outer layer to the inner layer (it is normal that the outer layer is black and the inner layer is dark gray). Pay attention to whether there is abnormal color under the outer layer to avoid buying second-hand leather with secondary dyeing or discoloration.
6). Wipe method
Wipe the leather surface with degreasing oil, and pay attention to whether there is fading or shedding, so as to avoid buying leather with secondary discoloration.
7), the origin of law
All countries in the world produce leather, but only Europe (Northern Europe, Italy, Austria and Germany, etc.). ) has a long history, and naturally its leather processing level will be much higher than that of low-grade Southeast Asian leather.
8), certificate method
The leather in the factory has a clear source, origin, trademark, leather measurement project and leather use authorization, and so on.
9), guarantee method
This is the easiest way. When buying leather chairs, don't forget to ask the store if there is a warranty service card. First, avoid buying inferior leather; Second, develop the habit of regular maintenance; Third, providing permanent after-sales service can kill three birds with one stone.
Identification method of dermis and fake skin
10), finger method; When you press your finger on the skin, there will be fine wrinkles on the surface. When the finger is raised, the wrinkles disappear from the dermis immediately. Artificial leather and synthetic leather do not wrinkle.
1 1), water method; Drop a little water on the leather, and then dry the water stain. It feels sticky and wet. It's genuine leather.
12), perception method; Take the leather front and observe it carefully with your eyes. Dermal has pores, artificial leather has no pores. Look at the reverse side of the leather and look for the part that is not folded. If it is base cloth, it must be artificial leather or synthetic leather.
B. Identification of trimmed dough, secondary leather and reclaimed leather
When the leather is folded in half and relaxed, the wrinkles disappear from the cowhide immediately, but the wrinkles will not disappear from the recycled leather.
Differentiation of dermis:
Dermal is the raw skin stripped from cattle, sheep, pigs, horses, deer or other animals. After tanning in leather factory, leather materials with various characteristics, strength, feel, color and patterns are made. Wholesale Nike Air Force 1 is an essential material for modern leather products. Among them, cowhide, sheepskin and pigskin are the three raw materials for tanning. There are two kinds of dermis: the first layer and the second layer.
1, smell it first. The smell of artificial leather is similar to the pungent smell of plastic. The taste of real leather is quite special, generally it is the taste of leather. You can get some real leather to smell first.
2. Look at the ductility of leather. The dermis is soft and elastic. Artificial leather is much worse.
3, then look at the pores. There are clear pores and patterns on the surface of dermis, well-proportioned fine pores in cowhide, thick and sparse pores in yak skin and fish-scale pores in goatskin.
4, you can also use the method of ignition. Tear off a little fiber from the back of dermis and artificial leather, and it is artificial leather that emits a pungent smell and forms a knot after ignition; It's the real leather that gives off the smell of hair and won't get hard bumps.
In addition, some leather products on the market are hard to distinguish from the surface because they are coated with an organic material during the production process, but they can be distinguished from the back of the leather. If you can't tell when you buy it, you can ask a professional to identify it.
Actually, the first one is my most commonly used one. Because now artificial leather is getting closer and closer to real leather, only the taste can't be made.
Why is the dermis soft?
The fundamental reason why leather is soft is that when making leather, oil is introduced into animal skin to form an oil film, which covers the surface of fibers in the skin, that is, the fibers in the skin are separated by an oil film with appropriate thickness. In this way, the friction between fibers in leather is equivalent to the friction of oil molecules, so leather will be soft ~ ~ ~ Its principle is similar to that of sponge, except that the fibers on the inner surface of dermis are separated by an oil film, so that there are slidable pores between the inner dermis.
Why does dermis harden?
In the natural state, the oil introduced into leather will slowly evaporate with time, or the oil film will be destroyed by other reasons. For example, when it is hydrolyzed in water or high temperature environment, the oil film is destroyed and the oil evaporates, so the fibers in leather stick together, making the leather hard, brittle and even cracked. In short, the root cause of leather hardening and embrittlement is the mutual adhesion between fibers in leather.
Of course, there is also the hardening of the dermis layer caused by coating an outer film, and this hardening is also due to the destruction of the oil film between the fiber surfaces inside the leather.
How to maintain genuine leather?
When the oil film between the inner fibers of leather is damaged or lost, high-quality oil film should be re-injected into the surface between the inner fibers of leather, such as leather care agent simulating leather oil. The method is as follows:
Lay the hardened leather, such as leather coat, flat on the table, apply high-quality leather care agent, such as leather care agent that simulates oil, and wait for natural drying. Be careful, please don't rush for success. If you blow dry with hot air, it will destroy the oil that has been injected into the skin again. After injecting imitation leather oil for 2~3 times, naturally drying, put your wallet in the middle with both hands, simulate the principle of playing cotton, and pat lightly like clapping your hands to make the fibers in the skin vibrate, which is conducive to releasing the adhesion of the fibers in the skin. Then the epithelium simulates oil, and so on. After many times of epithelium simulating oil, the dermis will become soft.
Other hardened leather, such as leather bags, is treated in the same way as this principle, that is, the leather is injected with imitation leather oil, and after natural drying, the leather is gently patted with an elastic soft object such as cotton to make the fibers inside the leather vibrate and help release the fiber adhesion in the leather, and then the imitation leather oil is injected until the leather becomes soft.
However, this method is only applicable to the leather with oil loss and hardening, not to the leather with outer membrane that closes the pores of the dermis, because it is difficult for the nursing agent to enter after the hair eyes are closed.
The difference between the first layer and the second layer:
(1) The first layer of skin is cattle, sheep and pig skin, with grain surface, natural scars, blood and tendon marks, occasional knife wounds during processing and extremely low utilization rate of belly. The first layer of imported leather also has the serial number of cattle. Full grain leather can be distinguished by pore thickness and density. There are many kinds of cowhide, including cowhide, beef cowhide, grazing cowhide, bull cowhide, castrated bull cowhide, castrated bull cowhide and so on. In China, there are cowhide, buffalo hide, yak skin and yak skin. Among them, the pores of buffalo hide are thicker and thinner; The pores of cowhide are thinner and denser than buffalo hide. The pores of sheepskin are fine, dense and a little inclined, mainly sheepskin and goatskin. Pigskin is easy to distinguish because it has 3~5 hairs. Generally, artificially raised pig skins and wild boar skins are the famous South American wild boar. This kind of wild boar skin has obvious characteristics of pig skin pores and grain surface. Because of its special collagen fiber structure, it can be processed into very soft garment leather or glove leather with high value. In addition, ostrich skin, crocodile skin, alligator skin, lizard skin, snake skin, bullfrog skin, marine fish skin (including shark skin, cod skin, sole skin, eel skin, pearl fish skin, etc. ), freshwater fish skin (including grass carp skin, carp skin and other pregnant fish skin) and hair fox skin (silver fox skin, green fox skin and so on. ).
The top skin is directly processed from the original skins of various animals, or the skins of cattle, pigs, horses and other animals with thick skins are cut into upper and lower layers, and the upper layer with tight fiber structure is processed into various top skins.
(2) The second skin consists of two layers with loose fiber structure, and is processed by spraying chemical materials or covering PVC and PU films.
Therefore, an effective way to distinguish the first skin from the second skin is to observe the fiber density on the longitudinal section of the skin. The top layer is composed of a dense and thin fiber layer and a slightly loose transition layer closely connected with it, which has good strength, elasticity and process plasticity. The second layer of leather has only a loose fibrous tissue layer, which can only be used to make leather products after spraying chemical raw materials or polishing. It maintains certain characteristics of natural elasticity and process plasticity, and the thickness requirement is the same as that of the first layer of leather.
The difference between buffalo hide and cowhide;
Buffalo hide: the surface is rough, the fiber volume strength is lower than that of cowhide, and other properties are close to cowhide.
Which sofa is better, buffalo hide or cowhide? Cowhide, of course, because cowhide has a high density.
The pores on the surface of cowhide are round and extend straight into the leather. Pores are compact and even, and arranged irregularly, like stars all over the sky. The pores on the surface of buffalo hide are thicker than those in cattle hide, the number of pores is less than that in cattle hide, and the leather is slack, which is not as detailed and plump as that in cattle hide.
In addition: cowhide and buffalo hide are what we usually call "genuine leather", which is different from synthetic leather in wear resistance. Mainly used for manufacturing leather shoes, wallets, belts, sofas, etc. The first layer of leather is almost twice as expensive as the second layer, because it is more wear-resistant than the second layer.
Usually, guests want to make a leather sofa. We suggest that they make the first layer+imitation leather (also called PVC). That is to say, when you sit on the sofa, you can make the first layer of leather where your hands and feet touch (where you need high wear resistance), and use imitation leather on the back of the backrest and armrest. It is both economical and affordable!
How to identify genuine leather!
Skin recognition knowledge
1: Identification of dermis
Touch by hand: that is, touch the leather surface by hand. If it feels smooth, soft, plump and elastic, it is genuine leather. But the general synthetic leather is hard, hard and soft.
At first glance, the hair and pattern of the dermis are clear, the pores of cowhide are well-proportioned and fine, the pores of yak skin are thick and sparse, and the pores of goatskin are fish-scale-shaped.
Smell: All dermis has the smell of leather; Moreover, artificial leather has a strong plastic pungent smell.
Ignition: tear off a little fiber from the back of genuine leather and artificial leather. After ignition, it is artificial leather that emits a pungent smell and forms a knot. It's genuine leather that smells like hair without induration.
2. Distinguish artificial leather from synthetic leather
With the above four basic identification methods, it is obvious to compare and identify artificial leather and synthetic leather. In addition, artificial leather and synthetic leather have the following characteristics:
1. When leather is pressed with fingers, there are no obvious pores and wrinkles. If there are wrinkles after pressing, they will not disappear naturally.
2. There are no pores on the leather surface, which is an important feature to identify the authenticity of leather.
3, cut off the corners and burn, there is a taste, but it is not the smell of burning hair.
3. How to distinguish cowhide, pigskin, horse skin and sheepskin?
Different types of leather have different characteristics and uses. For example, cowhide has fine surface and high strength, which is most suitable for leather shoes and leather goods; Sheep leather is light and soft, which is an ideal fabric for making leather clothes. Pigskin has good air permeability and moisture permeability.
Pig skin: The pores on the skin surface are round and thick, and extend obliquely into the skin. The pores are arranged in groups of three, and the leather presents many small triangular patterns.
Cowhide: Cowhide and buffalo hide are both called cowhide, but there are some differences between them. The pores on the surface of cowhide are round and extend straight into the leather. Pores are compact and even, and arranged irregularly, like stars all over the sky. The pores on the surface of buffalo hide are thicker than those in cattle hide, the number of pores is less than that in cattle hide, and the leather is slack, which is not as detailed and plump as that in cattle hide.
Horse skin: the hair on the leather surface is also oval, slightly larger than the pores of cowhide, and arranged regularly.
Sheepskin: The pores on the grain surface of leather are flat and round, and the pores are clear. They form a group of several, arranged in fish scales.
Leather quality appraisal
Cowhide can be divided into multiple layers (up to 8 layers). The outermost layer is the first layer with the best quality, followed by the second layer, which is not as good as the first layer in strength, elasticity and air permeability. Car seats must use the first layer of leather. A kind of synthetic leather sold in the market now is to stick a layer of adhesive film on the surface of the second layer of leather, which looks like the first layer of leather and has a delicate surface. Some merchants pretend to be the first layer of skin to deceive users, so we should pay attention to identification.
From a professional point of view, the identification of leather should be judged from the smell, specific gravity, light resistance, migration resistance, atomization, thermal yellowing and friction resistance of automobile leather. Because most car owners have no professional knowledge in this field, it is difficult to judge. You might as well use the following simple methods to identify.
1, labeling method
The back of the leather in the factory will be marked with the date of production, the name and area of the leather factory, etc. Of course, the production date should not be too long, and the leather over 3 years should pay attention to whether there is mildew.
2. Smell method
Good leather should not have pungent smell after treatment, too much solvent smell and paint smell are not good.
3. Heat resistance method
It is best to ask the manufacturer for a small piece of leather and burn the sample with cigarette butts for about 2 ~ 3 seconds to avoid buying artificial leather products; Because of the large contact area, it takes a long time to burn with a lighter.
4. Watching method
Under the magnifying glass of 30 times, we can see that leather is like the surface of the earth, with holes and good air permeability. Automobile leather needs special treatment such as wear resistance and light resistance, and pores will be covered.
5, cutting method
When cutting leather with a blade, the color of leather should be consistent from the outer layer to the inner layer (it is normal that the outer layer is black and the inner layer is dark gray). Pay attention to whether there is abnormal color under the outer layer to avoid buying second-hand leather with secondary dyeing or discoloration.
6. Wipe method
Wipe the leather surface with degreasing oil, and pay attention to whether there is fading or shedding, so as to avoid buying leather with secondary discoloration.
7. Origin method
All countries in the world produce leather, but only Europe (Northern Europe, Italy, Austria and Germany, etc.). ) has a long history, and naturally its leather processing level will be much higher than that of low-grade Southeast Asian leather.
8. Certificate Law
The leather in the factory has a clear source, origin, trademark, leather measurement project and leather use authorization, and so on.
9. Guarantee Law
This is the easiest way. When buying leather chairs, don't forget to ask the store if there is a warranty service card. First, avoid buying inferior leather; Second, develop the habit of regular maintenance; Third, providing permanent after-sales service can kill three birds with one stone.
Identification method of dermis and fake skin
1, finger method; When you press your finger on the skin, there will be fine wrinkles on the surface. When the finger is raised, the wrinkles disappear from the dermis immediately. Artificial leather and synthetic leather do not wrinkle.
2. Water use method; Drop a little water on the leather, and then dry the water stain. It feels sticky and wet. It's genuine leather.
3. Perception method; Take the leather front and observe it carefully with your eyes. Dermal has pores, artificial leather has no pores. Look at the reverse side of the leather and look for the part that is not folded. If it is base cloth, UGG classic short must be artificial leather or synthetic leather.
Identification of trimmed skin, double skin and regenerated skin
When the leather is folded in half and relaxed, the wrinkles disappear from the cowhide immediately, but the wrinkles will not disappear from the recycled leather.
The difference between sheepskin and goatskin
It is sometimes difficult to distinguish goat skin products from goat skin products in the market. Let's introduce their respective characteristics and distinguishing methods.
Sheepskin: It is characterized by oblate pores on the grain surface, which obliquely penetrate into the leather, and several pores are arranged in a group, which is scaly or zigzag. "Water ripple" and other pattern features. Sheepskin is divided into sheepskin and goatskin.
Sheepskin: The leather contains a lot of fat. The fiber structure of leather is slack, very soft, with fine grain surface and great ductility, but it is not firm.
Goatskin: There is less fat in the cortex, and the fiber tissue is fuller, stronger and more durable than sheepskin.
The difference between them: the grain surface of sheepskin is fine and smooth; Goatskin has clear pores and elastic leather. No matter what kind of sheepskin products make clothes, the patterns are beautiful, the luster is soft and natural, light, soft and elastic, but the strength is not as good as that of cowhide and pigskin.
The epidermis is located under the hair and close to the dermis, which is composed of epidermal cells with different shapes. The thickness of the epidermis varies from animal to animal, for example, the thickness of the epidermis of cowhide is 0.5 ~1.5% of the total thickness; 2-3% of sheepskin and goatskin; While pigskin is 2-5%. The dermis is located under the epidermis, between the epidermis and subcutaneous tissue, and is the main part of rawhide. Its weight or thickness accounts for more than 90% of the rawhide.
How to print the first skin and the second skin
How to distinguish the first skin from the second skin: the first skin and the second skin. (1) The first layer of skin is cattle, sheep and pig skin, with grain surface, natural scars and traces of blood tendons on the skin surface, occasional knife wounds during processing and extremely low utilization rate of belly. The first layer of imported leather also has the number plate of the ox. Full-grain leather can be polished, and which animal leather belongs to can be distinguished from the pore thickness and density. There are many kinds of cowhide, including cowhide, beef cowhide, grazing cowhide, bull cowhide, castrated bull cowhide, castrated bull cowhide and so on. In China, there are cowhide, buffalo hide, yak skin and yak skin. Among them, the pores of buffalo hide are thicker and thinner; The pores of cowhide are thinner and denser than buffalo hide. The pores of sheepskin are fine, dense and a little inclined, mainly sheepskin and goatskin. Pigskin is easy to distinguish, because the rule of long hair is the distribution of 3~5 small pieces. Generally, artificially raised pig skins and wild boar skins are used. The famous South American wild boar. This kind of wild boar skin has obvious characteristics of pig skin pores and grain surface. Because of its special collagen fiber structure, it can be processed into very soft garment leather or glove leather with high value. In addition, ostrich skin, crocodile skin, crocodile skin, lizard skin, snake skin, bullfrog skin, marine fish skin (including shark skin, cod skin, sole skin, eel skin, pearl fish skin, etc. ), freshwater fish skin (including scaly fish skin such as grass carp skin and carp skin) and hairy fox skin (silver fox skin and blue fox skin, etc. ). The top skin is directly processed from the original skins of various animals, or the skins of cattle, pigs, horses and other animals with thick skins are cut into upper and lower layers, and the upper layer with tight fiber structure is processed into various top skins. (2) The second skin consists of two layers with loose fiber structure, and is processed by spraying chemical materials or covering PVC and PU films. Therefore, an effective way to distinguish the first skin from the second skin is to check the fiber density in the longitudinal section of the skin. The top layer is composed of a dense and thin fiber layer and a slightly loose transition layer closely connected with it, which has good strength, elasticity and process plasticity. The second layer of leather has only a loose fibrous tissue layer, which can only be used to make leather goods after spraying chemical raw materials or polishing. It maintains certain characteristics of natural elasticity and process plasticity, but its strength is poor, and the thickness requirement is the same as that of the first layer of leather. Answer: Ruili is popular-local tyrants (level 5) July 2009-18 00: 58 Leather is divided into two types: first leather and second leather. (1) The first layer of skin is cattle, sheep and pig skin, with grain surface, natural scars and traces of blood tendons on the skin surface, occasional knife wounds during processing and extremely low utilization rate of belly. The first layer of imported leather also has the number plate of the ox. Full-grain leather can be polished, and which animal leather belongs to can be distinguished from the pore thickness and density. There are many kinds of cowhide, including cowhide, beef cowhide, grazing cowhide, bull cowhide, castrated bull cowhide, castrated bull cowhide and so on. In China, there are cowhide, buffalo hide, yak skin and yak skin. Among them, the pores of buffalo hide are thicker and thinner; The pores of cowhide are thinner and denser than buffalo hide. The pores of sheepskin are fine, dense and a little inclined, mainly sheepskin and goatskin. Pigskin is easy to distinguish, because the rule of long hair is the distribution of 3~5 small pieces. Generally, artificially raised pig skins and wild boar skins are used. The famous South American wild boar. This kind of wild boar skin has obvious characteristics of pig skin pores and grain surface. Because of its special collagen fiber structure, it can be processed into very soft garment leather or glove leather with high value. In addition, ostrich skin, crocodile skin, crocodile skin, lizard skin, snake skin, bullfrog skin, marine fish skin (including shark skin, cod skin, sole skin, eel skin, pearl fish skin, etc. ), freshwater fish skin (including scaly fish skin such as grass carp skin and carp skin) and hairy fox skin (silver fox skin and blue fox skin, etc. ). The top skin is directly processed from the original skins of various animals, or the skins of cattle, pigs, horses and other animals with thick skins are cut into upper and lower layers, and the upper layer with tight fiber structure is processed into various top skins. (2) The second skin consists of two layers with loose fiber structure, and is processed by spraying chemical materials or covering PVC and PU films. Therefore, an effective way to distinguish the first skin from the second skin is to check the fiber density in the longitudinal section of the skin. The top layer is composed of a dense and thin fiber layer and a slightly loose transition layer closely connected with it, which has good strength, elasticity and process plasticity. The second layer of leather has only a loose fibrous tissue layer, which can only be used to make leather goods after spraying chemical raw materials or polishing. It maintains certain characteristics of natural elasticity and process plasticity, but its strength is poor, and the thickness requirement is the same as that of the first layer of leather.