Main classification of PVC materials

PVC can be divided into soft PVC and hard PVC. Among them, hard PVC accounts for about 2/3 of the market, and soft PVC accounts for 1/3. Commonly used in soft PVC floor, ceiling, and the surface of leather, but because of the soft PVC contains softening agent (which is the difference between the soft PVC and hard PVC), easy to brittle, not easy to save, so its use range was limited. Hard PVC does not contain softener, so it is flexible, easy to shape, not brittle, non-toxic and pollution-free, and has a long shelf life. Therefore, it has great development and application value. The essence of PVC is a kind of vacuum plastic-absorbing film, which is used for surface packaging of all kinds of panels, so it is also called decorative film and adhesive film, which is applied in many industries such as building materials, packaging and medicine. Among them, building materials industry accounts for the largest proportion, which is 60%, followed by packaging industry, and other small range of application industries.

Chlorine atoms are found in the molecules of vinyl chloride. Due to the dipole effect of c-cl bond, it is a material with strong polarity. PVC has good acid and alkali resistance, wear-resistance, flame resistance and insulation performance, but poor light and thermal stability. Commercially, there are four ways to prepare PVC: suspension method, bulk method, emulsion method and solution method. Suspension is most common, and most of the PVC resins used are of this type. According to the amount of plasticizer (usually dibutyl phthalate and dioctyl phthalate), the product is divided into hard, semi-hard and soft materials. Rigid PVC contains plasticizer of 10-25%, semi-rigid PVC of 30-40%, soft PVC of 40-70%. All PVC products must contain a certain amount of stabilizer to avoid degradation during processing. The plasticizer in soft PVC products is to make the polymer soft. The choice of plasticizer or the mixture of plasticizer ultimately depends on the desired properties of the finished product. Most plasticizers also play the role of processing AIDS to some extent. The plasticizer reduces the melting temperature and viscosity of the resin, thus preventing the resin from sticking to the metal parts of the processing equipment.