What Are the Key Factors Affecting Polyurethane Roller Performance and Market Development?
The performance of polyurethane rollers depends not only on the operating environment but also closely on their material composition and manufacturing process. The main factors affecting roller performance include the molecular weight of polyols and the isocyanate (NCO) content in the prepolymer, both of which determine the mechanical and processing characteristics of the polyurethane elastomer.
Firstly, from a molecular structure perspective, the molecular weight of polyols directly affects the flexibility and strength of the rollers. For polyester-based polyurethanes, increasing the molecular weight enhances mechanical properties; for polyether-based polyurethanes, higher molecular weight improves flexibility but reduces tensile strength and modulus. Therefore, in practical production, the polyol molecular weight is generally controlled between 1100 and 2200 to balance performance and processability.
Secondly, variations in NCO content in the prepolymer are equally important. Moderately increasing NCO can enhance hardness, tear resistance, and tensile strength, while reducing viscosity, which is beneficial for mixing and degassing. However, excessively high NCO content can cause overly rapid curing, shortening pot life and negatively affecting casting processes. Therefore, NCO content is typically maintained between 2.4% and 6.5% for optimal results.
In terms of performance characteristics, polyester-based polyurethane rollers offer high mechanical strength and heat-aging resistance, along with excellent ozone and chemical resistance, making them widely used in the automotive, machinery, electrical, leather, medical, and sports equipment industries. Compared to polyether types, they have slightly lower cold resistance but overall stronger performance, suitable for high-load and long-term applications.
Regarding market demand, since the 1980s, domestic polyurethane rollers have gradually replaced natural rubber rollers, being widely applied in paper, steel, dyeing, and textile industries. Particularly in paper machine pressing sections, polyurethane roller surfaces can withstand higher line pressures, improving dewatering efficiency and significantly reducing energy consumption.
On the manufacturing side, horizontal production technology for polyurethane rollers has improved in recent years. By optimizing raw material mixing, mold pretreatment, and casting processes, rollers with fewer surface defects and better overall performance are produced. Specifically, casting under mold temperatures of 80–85°C helps achieve a dense and uniform roller layer. These technological advances have promoted the adoption and application upgrade of polyurethane rollers in the domestic market.