What methods can be used to improve the high-temperature resistance of PP/PU casters?

Improving the high-temperature resistance of PP (polypropylene) and PU (polyurethane) casters requires combining material properties with formulation optimization, process improvement, and structural design. Specific methods are as follows:

1. Formulation Optimization (Core Method)
PP casters: Adding 10%-30% chopped glass fiber filler can increase the heat deformation temperature from 60-80°C to 120-150°C, while also enhancing rigidity and impact resistance. A hindered phenol antioxidant (such as 1010) and a phosphite auxiliary antioxidant (such as 168) can be used to inhibit oxidative degradation at high temperatures and delay aging.

PU casters: Using high-temperature-resistant isocyanates (such as MDI) and polyols as raw materials, adjusting the crosslink density can increase the base material's upper temperature resistance to 120-150°C. Adding nano-scale inorganic fillers (such as silica) enhances intermolecular stability and reduces softening and deformation at high temperatures.

2. Surface Treatment and Coating Protection
Spray a high-temperature-resistant coating (such as a silicone coating or ceramic-based coating) on the wheel surface to form a dense protective film that blocks heat conduction. This coating increases the temperature resistance of PP casters to 100-120°C, and that of PU casters to over 150°C. It also enhances oil and chemical resistance, making it suitable for high-temperature, oily environments.

3. Process and Structural Improvements
PP casters utilize injection molding to increase the holding pressure and cooling rate to reduce internal stress and prevent cracking at high temperatures. PU casters undergo a high-temperature vulcanization process to increase cross-linking and enhance structural stability. The structure utilizes a composite design of a metal bracket and polymer wheel tread. The metal portion partially absorbs heat conduction, reducing the load on the substrate and making it suitable for heavy-load, high-temperature environments.

These methods can be combined based on the required operating temperature (e.g., 100-150°C) to effectively extend the service life of the casters in high-temperature environments such as industrial workshops and baking equipment.