Full definition
Polyurethane rubber, categorized into AU (polyester-based) and EU (polyether-based), is a versatile elastomer known for its superior mechanical properties compared to natural rubber. AU grades exhibit exceptional abrasion resistance, outperforming natural rubber in sliding wear by a factor of 3 to 10 times. This makes it particularly valuable in applications where wear and tear are significant concerns. The tensile strength of polyurethane rubber ranges from 30 to 70 MPa, while its tear resistance and load-bearing capacity are outstanding, with a low compression set, ensuring durability even under constant stress. The hardness of polyurethane rubber can vary significantly, spanning from 20 Shore A to 75 Shore D, allowing for a wide range of applications depending on the required flexibility and rigidity.
The processing of polyurethane rubber typically involves casting from liquid systems, which consist of a prepolymer and curative, often based on TDI or MDI. The curing process occurs at temperatures between 80-110°C, with a post-curing phase at 100°C for 16 to 24 hours to enhance properties. This method of processing allows for the production of parts with intricate shapes and high precision. However, the continuous service temperature limit for polyurethane rubber is around -30°C to +80°C, beyond which it may degrade. Its resistance to various conditions varies between the two families, with AU showing superior abrasion and oil resistance, while EU offers better hydrolysis and microbial resistance, making it suitable for diverse environments.
Despite its numerous advantages, polyurethane rubber does have limitations. It degrades at temperatures exceeding 80°C and is susceptible to hot water, steam, and UV radiation, which can compromise its integrity over time. Applications for this elastomer are extensive, including conveyor belt scrapers, mining screen panels, industrial wheels and rollers such as those found in forklifts and cranes, hydraulic seals, metal-forming pads, pipeline pigs, and abrasion-resistant linings. These applications highlight the material's versatility and its critical role in various industrial processes, providing effective solutions where durability and performance are paramount.