That's an excellent and very practical question! As someone who's worked with municipal waste management specs, I can tell you that UV resistance is a major factor in the design of modern plastic trash cans. The short answer is: yes, UV rays are a threat, but quality cans are specifically engineered to hold up against them.
Standard, untreated plastics will absolutely become brittle when exposed to prolonged sunlight. The UV radiation breaks down the polymer chains in the plastic—a process called photodegradation. This leads to fading, surface cracking, and eventually, a container that can shatter from a simple impact.
However, urban-grade plastic trash cans are rarely made from untreated materials. Here’s how they combat UV damage:
1. UV Stabilizers and Additives: During manufacturing, compounds like carbon black (which gives many bins their dark gray color) or specialized chemical UV inhibitors are mixed into the plastic resin. These additives absorb or screen out UV radiation before it can damage the polymer structure.
2. Material Choice: High-density polyethylene (HDPE) is the most common material. It's inherently more resistant than some plastics, and when combined with stabilizers, it performs very well outdoors. Polypropylene is another common, durable choice.
3. Thickness and Design: Thicker walls not only provide strength but also mean there's more material to degrade before the structural integrity is compromised. Ribbed designs also add strength to counteract potential embrittlement.
So, will a good urban trash can become brittle? Not for many years if it's a quality product. A cheap, thin, non-UV-protected bin might start failing in a single season of intense sun. A commercial-grade can with proper additives should last 5-10 years or more before showing significant brittleness, even in direct sun.
You can extend their life by placing them in shaded areas when possible, but for most city applications, that's not feasible. The key is to look for cans marketed for "commercial," "outdoor," or "all-weather" use, as these specify UV-protected materials. The fading of color over time is normal, but it shouldn't mean the plastic is ready to crumble.