The difference between PVC artificial leather and PU artificial leather
The difference between PVC artificial leather and PU artificial leather
Artificial leather is a plastic product that looks and feels like leather and can be used instead. It is usually made of fabric as the base, coated with synthetic resin and various plastic additions. There are three main categories: PVC artificial leather, PU artificial leather and PU synthetic leather.
In the 1980s, most people could not afford expensive leather materials for leather clothing. In response to market demand, artificial leather, which was imitation leather, became popular and was widely used in clothing and bag making. Such artificial leather clothes and bags that imitate leather once flooded the streets, satisfying people’s desire to wear leather. Compared with leather, artificial leather is prone to aging and wear, and contains a large amount of chemical raw materials, which is harmful to human health. Moreover, the clothes and bags made of artificial leather gradually lose market because they are not durable, until they are replaced by other raw materials.
Artificial leather produced with PVC resin as raw material is called PVC artificial leather (referred to as artificial leather); artificial leather produced with PU resin as raw material is called PU artificial leather (referred to as PU leather); artificial leather produced with PU resin and non-woven fabric as raw materials is called PU synthetic Leather (referred to as synthetic leather).
PU is the abbreviation of English polyurethane, and the Chinese chemical name is “polyurethane”. PU artificial leather is a skin made of polyurethane. It is widely used in the decoration of bags, clothing, shoes, vehicles and furniture. It has been increasingly recognized by the market. Its wide range of applications, large quantities and varieties cannot be satisfied by traditional natural leather. The quality of PU artificial leather also varies, and good PU artificial leather is even more expensive than genuine leather.
PU, called polyurethane in the textile field, is one of the best thermal insulation materials in the world. A type of polymer whose main chain contains -NHCOO- repeating structural units. It is polymerized from isocyanate (monomer) and hydroxyl compound and has good oil resistance, toughness, wear resistance, aging resistance and adhesion. Suitable for materials with a wide temperature range (-50~150℃)! So the cold resistance of PU is good!
But this is theoretically speaking. In fact, due to the uneven quality of the processes and raw materials used by various PU leather manufacturers, the general cold-resistant temperature is around -20 degrees! This material is used in ready-to-wear or waterproof and breathable products! The so-called semi-PU actually means that the top layer is PU and the lower half layer is made of PVC material!
PVC is called polyvinyl chloride in the textile field! It is divided into soft PVC and hard PVC. Hard PVC accounts for about 2/3. It is used in many applications from pipes to daily necessities. Soft PVC is as mentioned above. , it is mostly used in clothing, especially some exported raincoats, or soft-feel ready-made clothes. However, because it is used in the field of soft-feel ready-made clothes, some softeners, slip agents, etc. must be added, and these substances contain harmful substances to the human body. Substances that cause harm, so PVC has gradually become a non-environmentally friendly material and will be banned in the EU on August 1, 2008!
PU does not have these problems in terms of technology, so the harm to the human body is minimal among simulated leathers, even similar to genuine leather products (because genuine leather products often need to be dyed, finished, etc., there will also be some Chemical agents remain on it)!
Furthermore, because there is a big difference in technology between PVC and PU, the price is also very different. PU is much more expensive than PVC!
The difference between the two is actually quite simple:
1. If it can be burned, PVC will emit green smoke, while PU will only emit black smoke;
2. The elasticity of PVC is worse than that of PU, and its recovery performance after stretching is also worse than that of PU;
3. PVC will be slippery because some other substances are added to it, while PU is just its essence, so it will be stickier or slimmer;
Production
Including base fabric treatment, glue preparation, coating, laminating, gelling, surface treatment, embossing, cooling, coiling and other processes. There are four main production methods.
Direct coating
Apply the rubber material directly to the pretreated base fabric with a scraper, then put it into the plasticizing box for gelation and plasticization, and then go through processes such as embossing and cooling to get the finished product. This method can produce various cloth-based ordinary artificial leather, filmed artificial leather and foamed artificial leather.
Transfer coating
Also called indirect coating method. Use a reverse roller or scraper to apply the paste on the carrier (release paper tape or stainless steel tape). After gelation, compound the cloth base on the gelled material layer without tension, and then After plasticizing, cooling and peeling off the carrier, and then post-processing, the finished product is obtained. This method is suitable for producing knitted fabric or non-woven fabric-based foam artificial leather and ordinary artificial leather.
Calendering and lamination
According to the formula requirements, the resin, plasticizer and other ingredients are measured and put into the kneader to mix evenly. After being refined by an internal mixer, an open mill or an extruder, they are sent to a three-roller or four-roller calender. (See Plastic Machinery Calendering into a film of required thickness and width, laminated to a preheated base fabric, and then embossed and cooled to obtain the finished product. This method can produce various artificial leathers with different fabric bases. In order to improve the base fabric To improve the bonding effect with the film, a layer of adhesive is often applied to the base fabric.
Extrusion fit
The resin, plasticizer and other ingredients are mixed evenly in the kneader. After molding, the film layer is extruded into a certain thickness and width by the extruder, and then laminated to the preheated base fabric on a three-roller shaping machine. , and then go through preheating, film application, embossing, and cooling to get the finished product. This method is used to manufacture thicker products, such as floor leather, conveyor belts, etc.
PU synthetic�There has been rapid growth in terms of product quality, variety, and output. Its performance is getting closer and closer to natural leather, and some properties even exceed natural leather, reaching the point where it is difficult to distinguish between genuine and fake natural leather. It occupies a very important position in human daily life. ikB
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