Kone Elevator: PUR elastomers are mainly divided into casting type, thermoplastic type, compression type, and foaming type according to their processing methods. Among them, cast type PUR elastomer is the most important type. In recent years, with the development of reaction injection molding technology, the output of castable PUR elastomers has declined, but because castable PUR elastomers can maximize the characteristics of PUR elastomers, and their complex structures in molding large-scale It has unique advantages in terms of parts, so cast PUR elastomer is still one of the more active research fields.
The main advantages of polyurethane elastomer PUR:
1. Large adjustable range of performance. A number of physical and mechanical performance indicators can be changed within a certain range through the selection of raw materials and adjustment of the formula, so as to meet the different requirements of users for product performance. For example, hardness is often an important indicator for users. Polyurethane elastomers can be made into soft printing rubber rollers with a Shore A hardness of about 20, and also can be made into hard rolling rubber rollers with a Shore D hardness of 70 or more. This is difficult for ordinary elastomeric materials. Polyurethane elastomer is a polar polymer material composed of many flexible segments and rigid segments. As the proportion of rigid segments increases and the density of polar groups increases, the original strength and hardness of the elastomer will increase accordingly.
2. Excellent wear resistance. Especially under the working conditions in the presence of wetting media such as water and oil, its wear resistance is often several times to several tens of times that of ordinary rubber materials. Although metal materials such as iron and steel are very hard, they are not necessarily wear-resistant. For large water pumps in the Yellow River irrigation area, the metal orifice ring and protection ring of the overcurrent parts have been washed away by a large amount of sediment, which will cause severe wear and tear in less than hundreds of hours However, the mouth ring and protective ring covered with polyurethane elastomer continue to run for 1800 small advances without wearing. Others such as rice hulling rubber rollers, vibrating sieve sieve plates for coal preparation, running tracks in sports fields, dynamic oil seals for cranes and forklifts, elevator wheels and roller skates, etc. are also polyurethane elastomers. Where it comes in. What needs to be mentioned here is that in order to increase the friction coefficient of low- and medium-hardness polyurethane elastic components and improve the wear resistance under load, a small amount of aluminum disulfide, graphite or silicone oil can be added to this polyurethane elastomer. Lubricant.
3. Various processing methods and wide applicability. Polyurethane elastomers can be formed by plasticizing, mixing, and vulcanization (referred to as MPU) like general rubber; they can also be made into liquid rubber, cast by molding or spraying, potting, and centrifugal (referring to CPU); Granular materials, like ordinary plastics, are formed by injection, extrusion, calendering, blow molding and other processes (referred to as TPU). Molded or injection-molded parts can also be machined, such as cutting, grinding and drilling, within a certain hardness range. The diversity of processing makes the applicability of polyurethane elastomers very wide, and the application field is constantly expanding.
4. Oil resistance, ozone resistance, aging resistance, radiation resistance, low temperature resistance, good sound permeability, strong adhesion, excellent biocompatibility and blood compatibility. These advantages are the reason why polyurethane elastomers are widely used in military, aerospace, acoustics, and biology.