Casting polyurethane elastomer is called liquid rubber, which is a product produced by pouring a liquid reaction mixture into a mold cavity. It is also the most widely used and the largest output of polyurethane elastomers.
Key Benefits of Cast Polyurethane Elastomers
1. The performance can be adjusted in a large range. A number of physical and mechanical performance indicators can be changed within a certain range through the selection of raw materials and the 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 on products. Polyurethane elastomers can be made into soft printing rubber rollers with a Shore A hardness of about 20, and hard rolled steel rollers with a Shore D hardness of more than 70. This is difficult for general elastomer 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 in the working conditions with the presence of water, oil and other moist media, its wear resistance is often several to dozens of times that of ordinary rubber materials. Although metal materials such as steel are very hard, they are not necessarily wear-resistant. For example, in the large water pumps in the Yellow River irrigation area, the metal mouth rings and protective rings of the flow-passing parts are washed by a large amount of sand, and they will be severely worn and leaked within a few hundred hours. However, the mouth ring and protective ring (cyclone) coated with polyurethane elastomer have not been worn out for 1800 hours of continuous operation. What needs to be mentioned here is that to increase the friction coefficient of medium and low hardness polyurethane elastomer components and improve the wear resistance under load, a small amount of aluminum disulfide, graphite or silicone oil can be added to this type of polyurethane elastomer.
3. Various processing methods and wide applicability. Casting polyurethane elastomer can be molded, mixed and vulcanized like general rubber (referred to as MPU); it can also be made into liquid rubber, poured and molded or sprayed, potted, and centrifugally formed (referred to as CPU); It can be made into pellets, and it can be formed by injection, extrusion, calendering, blow molding and other processes like ordinary plastics (referring to TPU). Molded or injection-molded parts can also be machined for cutting, grinding, drilling, etc. within a certain hardness range. The diversity of processing makes the applicability of polyurethane elastomers very wide, and the application fields continue to expand.
4. Oil resistance, ozone resistance, aging resistance, radiation resistance, low temperature resistance, good sound permeability, strong adhesion, excellent biocompatibility and blood compatibility are the advantages of polyurethane elastomers in military industry, aerospace, acoustics, biology, etc. These are the reasons for its wide application in other fields.
