Are there any material requirements for casters used in trash cans?

Trash can casters have specific and strict material requirements. This is primarily due to their exposure to long-term waste leachate, dynamic loads, and adaptability to complex indoor and outdoor environments. Material performance directly determines the caster's lifespan, safety, and user experience. Specific requirements can be categorized into two key aspects: the wheel body material and the axle/connector material.

1. Wheel body material: It must meet the three core performance requirements of "corrosion and stain resistance, load-bearing and wear-resistant, and adaptability to specific scenarios."

Since the wheel body comes into direct contact with the ground and waste contaminants, the material must balance chemical stability and physical strength. Different material choices are appropriate for different scenarios.

Corrosion and stain resistance: It must withstand waste leachate (weakly acidic kitchen waste and weakly alkaline cleaning solutions) and everyday stains to avoid corrosion, cracking, and the absorption of dirt and odor. Ordinary plastics (such as polyethylene and polypropylene) are prohibited: These materials are easily permeated by acids and alkalis, leading to brittleness and surface cracking over time. Stains can easily become embedded in cracks and become difficult to clean.

Nylon (PA6/PA66) or polyurethane (PU) are preferred: Nylon is resistant to weak acids and alkalis, has a smooth surface that resists staining, and can be easily removed by rinsing with clean water. Polyurethane is resistant to chemical solvents and will not swell even when exposed to disinfectant. Its elasticity provides cushioning against bumps.

Load-bearing and wear-resistance: The wheel must be able to support the full weight of the trash can (20-30 kg for household use, 50-80 kg for commercial use) and withstand long-term rolling wear to prevent rapid deformation of the wheel tread. For light-load household applications (trash cans under 50L): Standard polyurethane wheels (Shore D 70-80) are recommended. They offer excellent elasticity, quiet operation, and low wear (≤0.2g per 1000 revolutions).
For heavy-load commercial applications (trash cans over 100L): Glass-fiber-reinforced nylon wheels (containing 15%-30% glass fiber) or high-hardness polyurethane wheels (Shore D 85-90) are recommended. Glass-fiber-reinforced nylon wheels offer a compressive strength of 90-110 MPa and are less susceptible to creep under long-term full loads. High-hardness polyurethane wheels offer 30% greater wear resistance than standard polyurethane wheels, making them suitable for rough outdoor surfaces.

Application suitability: The material must be compatible with indoor and outdoor temperature and humidity differences to prevent environmental degradation.

For humid indoor applications (kitchens and bathrooms): Polyurethane wheels are preferred, as they are less susceptible to moisture degradation.

For low-temperature/sun-drenched outdoor applications (community garbage stations): Nylon wheels are more weather-resistant, maintaining their toughness in temperatures between -30°C and 80°C, avoiding the problem of polyurethane hardening at low temperatures and softening at high temperatures.

2. Axle/Connector Material: Key requirements include "rust resistance, corrosion resistance, and load-bearing support."
The axle and connectors (such as the bushing and mounting bracket) are responsible for transferring load and ensuring wheel rotation. Poorly rust-resistant materials can easily cause corrosion and seizure due to landfill leachate, resulting in the caster becoming immobile. Specific requirements are as follows:

Ordinary carbon steel is prohibited: Carbon steel without rust-proofing will rust within 1-2 months after contact with moist landfill leachate. This rust can cause the bearing to seize, preventing the caster from turning.

Preferred Rust-Resistant Materials:

Basic Model: Choose a galvanized steel shaft (galvanized coating thickness ≥ 8μm) to withstand daily moisture and is suitable for dry indoor environments.

Advanced Model: Choose a stainless steel shaft (304/316). 304 stainless steel is mildly corrosion-resistant and suitable for kitchen and commercial trash cans. 316 stainless steel is highly corrosion-resistant and suitable for outdoor environments exposed to high salt spray (such as residential areas in coastal areas).

Connectors (brackets): Match the axle material. Choose galvanized steel or stainless steel brackets to avoid galvanic corrosion caused by dissimilar metal contact.

In summary, choosing the right material for your trash can caster isn't a matter of simply choosing plastic or metal. Instead, it needs to be tailored to the trash can's capacity (load-bearing requirements), usage scenario (indoor or outdoor, wet or dry), and the type of contaminant (food waste liquids or cleaning fluids). Choose nylon or polyurethane for the wheel body (for both corrosion resistance and load-bearing properties), and galvanized steel or stainless steel for the axle/connectors (to prevent rust and seizure). This ensures long-term, stable use of the casters and avoids frequent replacements due to substandard materials or safety hazards (such as wheel breakage and trash can tipping over).