I. Fabric
When identifying leather shoes, we should first check the upper material and determine the type of upper leather. For example, the grain surface layer of "genuine leather" has the original natural characteristics of cowhide: the pores are small, irregular and uniform; The pores and eyes of goatskin are "tile-shaped" in rows; Pigskin has a pile of three holes and is distributed in a figure of eight. Cowhide has fine tissue fibers, rough buffalo hide and rough pores and eyes. If the modified particle surface layer loses its original characteristics, it should be carefully classified and identified according to the processing technology.
Aniline leather coated with aniline is characterized by crystal clear light on the surface, bright, not dazzling and strong plasticity.
Natural leather is boiled into leather, and the cowhide is generally 5 ~ 6 mm thick. Shoes should be made in two layers with a leather machine. The surface layer is a granular surface layer, with fine and compact tissue fibers, smooth and beautiful appearance, good strength and wear resistance. The inner layer is a pile surface layer with thick fibers, large gaps and fluff on the surface. The surface of the first layer is smoother and smoother than that of the second layer, and the second layer is slightly rough. After coating, film transfer or film pasting, the surface of the two-layer leather may not be rough, but the film transfer leather has poor low temperature resistance and is easy to wrinkle at low temperature. The second layer of cowhide leather is smooth and has no obvious defects after embossing, while the second layer of pigskin leather often has three piles of pores faintly visible, where the luster is dark. It should be noted that the modified leather destroyed the original grain surface layer and then pressed the pattern. The pattern type can imitate cattle, sheep, pigskin and so on. However, the pattern has no pore eyes, and the pattern floats on the leather surface, while the pore eyes of the front leather exist, which can be identified by careful observation.
Artificial leather is coated with a layer of organic material on the basis of cloth, which can be divided into thin (imitation sheepskin) and thick (coated with foamed organic material and then pressed with patterns), and is mostly used for women's shoes and children's shoes. Synthetic leather is a kind of shoe upper leather made of organic fibers, coated with laminated flowers, which is mostly used in sandals. Regenerated leather is made by grinding leather residue and leather fiber, bonding them with adhesive under high pressure to form thin slices, slicing them to the required thickness, and then finishing them to make them have certain leather characteristics. They are widely used in luggage and leather parts, and a small amount are used in shoemaking. When distinguishing genuine leather from artificial materials, look at the appearance first. Genuine leather has no base, while artificial materials have a base. If you touch it again, the artificial material has a strong plastic feeling and a bright luster, but it feels cold in winter, and the leather is smooth, so it doesn't feel cold. Press the soft part of the front of the finished shoe with your thumb, and many fine and even patterns will appear in the dermis around your thumb. When your thumb is raised, the pattern will disappear. However, artificial materials may have no patterns, or rough patterns may appear. When the thumb is raised, the pattern does not disappear, indicating that the grain surface layer on the surface of the material has been separated from the mesh layer below, and the leather shoes made of this fabric are unqualified.
We can also observe the cross section of the upper when we distinguish genuine leather from artificial leather. The cross section of dermis is composed of irregular fibers. After scraping off the damaged skin fibers with nails, the cross section has no obvious change. For real leather, the texture of different parts is irregular, the nose smells fishy, while artificial leather smells plastic or rubber, and the texture rules of different parts are the same. Glued leather is a synthetic leather based on the inner layer of natural leather, which is not called "real leather", but an artificial surface layer attached to the loose fiber layer below natural leather.
Second, the shoe lining, hook heart and shoe seam
The insole of leather shoes is a reinforcing material used to prevent stretching deformation and improve the touch of the foot. It is required that the insole material has delicate hand feel, excellent air permeability, hygroscopicity and moisture drainage, and does not fade. Middle and high-grade leather shoes are made of natural leather and cotton cloth, while those made of artificial leather are low-grade products. The sole is the bottom of the pond. When checking, the shoes are folded at a 90-degree angle, so they will not crack. Some fake shoes use unqualified recycled leather pool bottom and cardboard non-woven pool bottom. Because of the low latex content in the material, it becomes soft after absorbing sweat. The hook of the sole-the steel plate that serves as the bridge between the insole and the outsole-may break away from the bottom of the pool and stab the sole.
Hook center is a key component installed between the outsole and midsole of leather shoes, which plays a supporting and shaping role and cannot be seen from the outside. When shopping, put your shoes flat on a solid table and press the hook core hard. Quality products should not be soft or deformed. On the other hand, it shows that the quality of the hook heart is poor, and its lumbar fossa will bulge or sag after wearing, which makes the feet feel extremely uncomfortable, painful to walk, affecting health and even hurting their feet. Length, width, elastic modulus, etc. The height of the hook center and the deformation after external force are stipulated by national standards and must have certain elasticity and rigidity. The material shall be 65 manganese steel, and the elastic limit load shall not be less than 290N N.
When checking the stitching of the vamp and the glue seam between the vamp and the sole, check whether there is a broken line and whether the stitching is standard and tidy. Glued leather shoes, the joint between the upper and the sole should be flat, without grooves, ridges, virtual seams and glue opening. The peeling strength of glued leather shoes is 54N/cm for men's shoes and 40 ~ 49 n/cm for women's shoes. If the sample initially sticks on the testing machine (that is, the bonding seam between the outer upper and the outsole is deformed and discolored), it is unqualified. Consumers can break the upper or press it inward. If there is discoloration or glue opening at the joint between the upper and the outsole, the adhesion is poor.
Third, the sole.
Outsoles of leather shoes are divided into rubber, imitation leather, plastic and rubber-plastic soles according to raw materials. The rubber sole is soft, elastic, non-slip, wear-resistant, heat-resistant and cold-resistant, and slightly heavier. Imitation shoes are light, hard, wear-resistant and elastic, but their elasticity is poor and they are not slippery. Plastic soles are wear-resistant, flat and smooth in appearance, bright in color, non-slip, poor in cold resistance and heavy. Rubber-plastic soles have the advantages of both rubber and plastic, and are wear-resistant, elastic and soft, which is the first choice for middle and high-grade shoes at present.
The thickness standard of the stressed part of the forefoot of the outsole should reach 2/3 of the total thickness of the outsole. During inspection, the depth of inner and outer patterns of the stressed part of the outsole shall be calculated at the same time, and shall not exceed 1/3 of the total thickness of the outsole. If this standard is not reached, it can be judged as fake shoes. In addition to the thickness, the sole should also have folding resistance and wear resistance. Because soles are generally made of polymer materials, the folding resistance of soles is tested on a special folding tester according to national standards. After the soles are folded at a certain frequency, at a certain angle and for a certain number of times, the cracking length of the soles shall not exceed 40, 15 and 12mm according to different varieties. According to the national standard, the wear resistance test of the sole is carried out on a special wear tester, so that the measured sole contacts with the standard grinding wheel and is subjected to a certain pressure, and the grinding wheel rotates at a certain speed. After a certain wear time, according to different varieties, the length of wear marks does not exceed 16, 12, 10mm, which is qualified. A certain adhesive strength is needed between the outsole and outsole of travel shoes. The test shall be conducted on a universal material testing machine or a tensile testing machine, and the bonding strength shall not be less than 20N/cm.
Fourth, the heel
After the shoes are fixed, hold the heel and pull it with a tension machine to see how much tension you can bear. According to the heel standard of shoes, when doing visual inspection, first break the heel by hand and observe the deformation of the sub-opening (the opening at the joint between the outside and the heel). If the deformation is large, it may be that there is something wrong with the heel, then take off the insole and watch the heel installation. High-heeled shoes over 4cm must be fixed with a wooden screw, and the overall fastness of the heel is guaranteed by the wooden screw and several wooden nails inside. The wood should be made of good material, and the wooden screw should not be split when it goes in, otherwise the deformation or looseness of the heel can be observed by gently breaking the heel.
Verb (abbreviation of verb) appears.
Feel free to lay your shoes flat on the counter or glass plate to see if they are stable. When the shoes are placed on the table, they should stop shaking from side to side immediately. Looking back from the toe, the size of the inner and outer edges of the sole should be similar to that of the table, so it is better to keep balance. The heel of the shoe should be vertical up and down, and don't lean to the outside or inside; Looking at the upper from top to bottom, we can see the symmetry of the upper part and whether the outline of the shoe is deformed. It is best to take the straight line from toe to heel midpoint as the symmetry axis. See if the parts on the vamp are symmetrical, and it is best not to move back and forth because they are symmetrical inside and outside. The outline of the shoes should be held slightly to the inside of the shoes, and it is better to be smooth and round. The shoes twisted into flounces are inferior shoes.
In the appearance inspection of shoes, we should also pay attention to the fact that the upper is not allowed to have obvious defects, loose surface, coating peeling, cracking, discoloration and other phenomena. The overall structure of the shoes should be straight and flat, and there are no spikes exposed in the shoes. The same parts of the two shoes should be symmetrical, the hardness, color and structure of the soles should be consistent, and there should be no obvious difference between the length of the front upper and the height of the rear upper. The two uppers and soles should be closely combined, and the uppers should not have obvious folds.
Six, manual testing
Touch the inner cavity of the shoe with your hand to see if there is any unevenness in the shoe. Any place where you can touch your feet can't be uneven, otherwise your feet will blister, and under normal circumstances, there must be insoles in your shoes. The insole can keep the inside of the shoe clean, and it can also cover several uneven nail holes on the insole. Under normal circumstances, men's shoes are half insoles, and women's shoes should be integral insoles. Then pinch the heel of the vamp with your hand to see if it is stiff and elastic. Don't use too much force, or you will hurt your ankle. The insole of a shoe is the trunk and skeleton of the shoe, so it is better to press the waist hard into the insole. Touch the insole downward with the tip of your index finger, so that the index finger is close to the top of the lateral ankle, and see if the second knuckle line of the index finger is consistent with the height of the lateral ankle. General daily shoes, social etiquette shoes and fashion shoes should be slightly higher than the second knuckle line of the index finger. The back uppers of low-waisted sports shoes and casual shoes are all soft-mouth structures, and the height of the lateral ankle uppers can be slightly higher than the second knuckle line of the index finger. Insert the tip of the middle finger under the toe sole to see if the toe height is appropriate. When the toe of the toe is just enough for the thickness of the middle finger belly, it means that the toe of the toe is just qualified. When the toe toe is too large, the stability decreases; When it is too small, the shoes are easy to deform and the feet are easy to get tired.
After the quality inspection, choose the shoe type and shoe size that match your foot type characteristics to try on. The height of the lateral opening of short waist shoes should be below the lateral ankle bone, and you must not touch the lateral ankle bone, otherwise it will be difficult to move. In addition, in the strict quality inspection of high-grade leather shoes, we should also pay attention to whether the upper has loose shell, cracked pulp, fading and other phenomena. Usually we use the methods of pressing, pushing and kneading. "Press" means putting the index finger and middle finger into the shoe, and gently pressing the vamp with the thumb of the other hand within the distance between the two fingers. If there are thick wrinkles, it is loose shell; "Top" means putting your hand into the shoe and gently pushing the upper with your forefinger and middle finger. If there are obvious "white flowers" silk lines, which do not disappear after relaxation, it is pulp cracking; "Wipe is to wrap the index finger with white soft gauze and dry-wipe it back and forth five times with moderate strength on the upper surface. Gauze will fade when it is stained with color.