The Difference Between PVC Synthetic Leather And PU Synthetic Leather

Consumers usually remove the dermis. synthetic leather Such as: PVC, PU Leather unification It is called artificial leather or imitation leather. Both PVC and PU are polyvinyl chloride (plastics), but the manufacturing processes of these two products are not the same.

During the manufacturing process, PVC leather should be mixed into plastic paste by hot melt. thickness It is evenly coated on the T/C knitted fabric base and then foamed into the foaming furnace, so that it has the flexibility to adapt to the production of various products and requirements. Surface treatment (dyeing, embossing, polishing, matting, milling and surface raising) is carried out on the basis of specific product requirements.

PU leather is more complex in manufacturing process than PVC leather. Because PU's bottom cloth is a canvas PU material with high tensile strength, besides coating on the top of the base cloth, it can also contain the bottom cloth in the middle, so that it can not see the existence of the cloth. The physical properties of PU leather are better than those of PVC leather. It has good resistance to twists and turns, good softness, high tensile strength and breathability (PVC no). The pattern of PVC leather is made by hot pressing with steel pattern roller. The pattern of PU leather is pressed on the surface of semi finished leather with a pattern paper first, and then after cooling, the paper leather is separated and treated by surface treatment. The price of PU leather is more than one times higher than that of PVC leather, and the price of PU leather with some special requirements is 2 to 3 times higher than that of PVC leather. The pattern paper needed for general PU leather can be scrapped only 4 to 5 times, and the use cycle of the pattern roller is long, so the cost of PU leather is higher than that of PVC leather.

The scope of application of these two materials is also somewhat different. In terms of footwear, PVC leather is mostly used in the interior or non weight bearing parts, or in the manufacture of children's shoes; PU leather can be applied to the fabric or weight bearing parts of shoes. In bags, more PVC leather is applicable. This is because the goods in the bag are different from the feet in the shoes, which do not emit hot air, and do not bear personal weight.

The difference between PU and PVC is relatively easy. From the side angle, the bottom cloth of PU is much thicker than PVC. There is also a difference in hand feeling. PU feels softer; PVC has a harder handle; it can also be burned with fire, and PU tastes much lighter than PVC.

Identification of semi PU leather

Synthetic leather is a good leather substitute for winter leather jackets. However, synthetic leather is made from TPU (polyurethane elastomer). The price of TPU is very expensive, so many manufacturers in China use PVC to replace them partly. They do this: first, they are coated with PVC (artificial leather) and then coated with TPU coating.

This price can be greatly reduced, but the plasticizer in PVC will migrate in less than a year, causing synthetic leather (actually artificial leather) to harden and crisp, so some customers bought a new leather jacket and crisp and cracked in less than a year. In fact, the factory in the production of synthetic leather is called semi synthetic leather or half PU leather.

Half PU leather can be identified in a very simple way, that is, when the copper wire is heated in the fire until the color of the fire is red (not green), the copper wire is also red in the fire. The copper wire is immediately put on the synthetic leather. The synthetic leather is melted onto the copper wire. Finally, the copper wire is placed on the fire. If the fire is green at this time, it is proved that PVC is half PU leather. If the fire is red at this time, it is proved to be PU leather.

This method is a simple method that can be used for general identification, but it can not be formally identified, because some additives in PU leather contain chlorine, which can cause misjudgement. The best way is to use infrared spectroscopy to identify, this method can only be identified by authoritative departments.

If you have infrared spectroscopy, you can also use the infrared spectrum analysis, the method is: first you use ethyl acetate to soak PU leather for 20 minutes, you can find three situations:

(1) PU leather can only be dissolved in ethyl acetate.

(2) PVC leather can be dissolved in ethyl acetate.

(3) half PU leather is swelling in the ethyl acetate solution, but the next layer is dissolved. You can use stainless steel tweezers to pleat the swelling cuticle and spread it on the filter paper, then use the infrared lamp to dry (or dry), then you can analyze the epidermis with infrared spectrum. The other parts can be made from solution on NaCl salt film, and NaCl IR salt film and film are used for infrared spectrum.

The difference between leather and leather

Leather and leather are two different things. Nowadays, many operators often refer to leather as skin and artificial leather as leather. This is incorrect and not rigorous.

Skin refers to the condition that the collagen fibers are still on the animal's body (referring to the chemical structure). Leather means removing the useless ingredients from the skins by physical and chemical treatment, and changing the chemical structure of the collagen fibers of the skin, which is different from that on the animal's body. In addition, leather is soft and easy to dry, and it is not easy to decompose in wet condition. Leather is the raw material for leather making. Leather is made of leather.

If the difference between leather and leather is confused with the difference between "natural leather" and "artificial leather", it is easy for the consumers of the laymen to get confused in concept and increase their difficulty in identifying leather products.

Traceability of synthetic leather

The composition and structure of natural leather can be simulated and used as a substitute for plastic products. Usually, the impregnated non-woven fabric is reticular layer, and the microporous polyurethane layer is used as the granular layer. Its positive and negative surfaces are very similar to leather and have certain air permeability, which is closer to natural leather than ordinary leather. It is widely used in making shoes, boots, bags and balls.

In 1964, DuPont Co made the first synthetic leather called Covent. The synthetic leather is made of synthetic fiber nonwoven fabric, reinforced with fabric in the middle and immersed in polyurethane elastomer solution similar to natural leather collagen fiber. The projectile solidified in water, and its solvent is replaced by water, thus forming tiny holes in the projectile. These holes are interconnected, forming a tough and elastic microporous layer from the inside to the outside, forming the surface of synthetic leather and forming a whole with the base. Because the capillary action formed by interwoven nonwoven fabric is beneficial to the absorption and migration of moisture, synthetic leather can partly show the respiratory characteristics of natural leather. In 1965, the Japanese Cola company developed 2 layers of synthetic leather, and cancelled the middle fabric to improve the softness of the finished product. In modern times, there are many kinds of synthetic leather, and all kinds of synthetic products have the common characteristics of synthetic fiber non-woven fabric base and polyurethane micro porous surface. For example, SBR or NBR latex base impregnation solution is used to get a special combination of non-woven fabric and polymer. There are 3 layers, 2 layers and single layer structure at different structural levels, and surface texturing and tanning technology are used to make suede synthetic leather.