Are polyurethane casters suitable for use in humid environments?

Polyurethane casters are suitable for use in humid environments, but three key compatibility criteria must be considered.

Polyurethane casters inherently possess a certain degree of water resistance and can function normally in humid environments (such as wet warehouses, aquaculture workshops, and short-term outdoor use on rainy days). However, consideration must be given to the caster's overall structural design and usage details to prevent component damage caused by moisture.

A detailed compatibility analysis is provided below:

In terms of material properties, the polyurethane tread has a stable molecular structure, is insoluble in water, and does not readily absorb water. This prevents the tread from softening, cracking, or accelerating aging in humid environments. Even with prolonged water contact (such as persistent water accumulation on the floor of an aquaculture workshop), the tread maintains its original elasticity and wear resistance. Unlike ordinary rubber casters, which absorb water and increase rolling resistance, this core advantage of polyurethane casters is their compatibility with humid environments.

However, the challenges posed by humid environments to casters primarily focus on the rust resistance of the metal components (hub and bearing) and the waterproofness of the sealing structure, rather than the polyurethane tread itself. Therefore, safe use requires the following three conditions:
The hub and bracket must be treated to prevent rust: Prefer galvanized, chrome-plated, or 304 stainless steel hubs and brackets to prevent the rapid rusting of ordinary cold-rolled steel (untreated) in humid environments, which can cause the caster to seize or the bracket to break. For example, in bathroom cleaning carts and aquatic product warehouse transfer carts, stainless steel polyurethane casters can resist moisture corrosion for a long time, while ordinary steel casters may rust within one to two months.

The bearings must be waterproof and sealed: Choose "double-sealed bearings" (such as double-sided rubber cap seals or contact seals) to prevent water from entering open or single-sealed bearings in humid environments. Moisture seeping into the bearing dilutes the grease, causing the bearing to rust and seize, affecting the smooth rotation of the caster. If the environment is humid and dusty (such as in wet construction sites), choose sealed bearings with dust covers to further isolate moisture and impurities.

Avoid prolonged immersion or strong water jets: Polyurethane casters can withstand "wet floors" and "intermittent splashing water," but they should not be immersed in water for extended periods (e.g., for more than 24 hours). Do not use a high-pressure water jet (pressure > 1 MPa) to directly flush the bearing seals. Long-term immersion can cause rust at the weld between the hub and bracket, and high-pressure water jets can break through the seal, causing water intrusion and damage to the bearing.

In summary, polyurethane casters are suitable for environments where humid but not subject to prolonged immersion, metal parts are rust-proofed, and bearings are well-sealed (such as humid warehouses, food processing and cleaning areas, and temporary outdoor transport in rainy weather).

For environments subject to "long-term immersion in standing water" (such as equipment near pools) or "high humidity and severe corrosion" (such as salt spray environments at the seaside), additional anti-corrosion coating should be applied to the caster metal parts, or polyurethane casters with all-plastic hubs should be selected for further weather resistance.