1. About leather
Usually consumers like to address animal skin with leather together without separating them. Actually leather is different from leather. They are both closely associated and strictly differentiated. “Leather” refers to the skin of various animals (namely raw skin). After a series of physical and chemical processing and tanning, the leather is turned into PU, a firm and durable material. Raw skin is extremely hard after drying up without physical or chemical processing and tanning. However it will soften again when soaked in water but is perishable. After chemical tanning, as the tanning agent firmly combines with protein fiber in the raw skin, the animal skin will becomes PU characterized soft, durable, distortion-resistant in case of water, dry and shrink-resistant, humidity and heat-resistant, chemical agent-resistant properties, high breathability, water permeability, and anti-aging properties. The other distinct difference between “skin” and “PU” is that most of the animal skin will curl up in 40-degree warm water, while PU after chromium salt tanning will not change even in 100-degree boiling water. With such outstanding properties, PU is not only used in daily leather products, leather shoes in particular, but also is widely used in industrial production as an indispensible material.
2. About PVC artificial leather
1. Definition: PVC, short for poly vinyl chloride, is a kind of chemical product, and a kind of ordinary thermoplastic resin. It is widely applied in the processing of many products, including apparels and suitcases. As animal protection is becoming increasingly important in European and American countries and due to the high price and hard-to-maintain property of genuine leather product, PVC, being a substitute for genuine leather, has become the most popular material for garment and household products in European and American markets.
2. Characteristics: High plasticity. It may possess the texture that is extremely similar to that of genuine leather but very durable. It has a service life of 10-12 years. If users attach importance to its cleaning, the service life may be lengthened. The properties of PVC are reliant upon the properties of plastic. It is characterized by small relevant density, large mechanical strength, acid-resistance, alkaline-resistance, grease-resistance, flexing endurance, water-resistance. The appearance of PVC is colorful, bright, and pretty with a variety of patterns. It is an ideal material for making all kinds of lady’s footwear. However due to the poor breathability and hygroscopicity of PVC, wearers may find PVC shoes “stuffy”.
3. Maintenance: Easy to maintain, mould-resistance. Keep the surface dry and clean, and avoid scratches from sharp objects.
4. Price: Being a chemical product, it is a lot cheaper than genuine leather.
Usually people like to call artificial leather made from PVC resin as PVC artificial leather. In daily life all kinds of PVC products of all colors seen everywhere, such as interior decoration, sofa material, car decoration, apparels, shoes, and suitcases, are all made from artificial leather.
3. About PU synthetic leather
PU, a kind of man-made synthetic material, has the texture of genuine leather, but very firm and durable. It is different from artificial leather.
a) Dry method PU
Dry method PU uses coating method with PU resin by coating on release paper with all kinds of pattern, which is dried and pasted before using base fabric (knitted fabric, non-women fabric) as base material for gluing and drying so that the pattern of the product is identical with that of the release paper; again after printing, its touch, endurance, and appearance may become comparable with those of genuine leather.
Synthetic leather made from dry method PU has outstanding strength, firm adhesive bonding, but less breathability. This kind of synthetic is mainly used to manufacture shoes, balls, bags, and furniture furnishings.
b. Wet method PU
Wet method PU method: Firstly cover a layer of PU resin evenly on women fiber fabric, then put the women fiber fabric covered with PU resin into the coagulating tank with water inside. When the PU resin layer is half coagulated, use the mould whose surface is engraved with patterns to stamp patterns onto the PU resin layer; then take out the woven fiber fabric and soak into rinsing bath to mature, which will result in PU synthetic leather with 3D patterns. This invention can reduce the manufacturing cost of synthetic leather and simplify its manufacturing technology; at the same time, the patterns of such synthetic have strongly stereoscopic impression, which makes it more like the natural texture of natural furs.
Wet PU manufacturing technology is a brand-new synthetic method developed after the dry method. Such synthetic leather has outstanding moisture permeability and breathability. Its hand feeling is soft, plump, light, and more like natural leather.