At our trash can factory, the short answer is that we do not rely on a single plastic resin to prevent heat-related cracking. The main resin we use is UV-stabilized high-density polyethylene (HDPE), often blended with linear low-density polyethylene (LLDPE). For certain heavy-duty or high-temperature models, we may also specify impact copolymer polypropylene (PP) where its stiffness and heat resistance suit the design. The key is the resin grade and the additive package, not just the polymer name.

HDPE gives trash cans the stiffness, chemical resistance, and dimensional stability needed for outdoor use. However, standard HDPE can become brittle under long-term sun exposure and repeated thermal expansion. To reduce cracking in heat, we select HDPE grades with good environmental stress crack resistance and blend in LLDPE. LLDPE improves impact strength and flexibility, helping the bin absorb stress from temperature changes, rough handling, and heavy loads.

We also add a UV stabilization system, typically hindered amine light stabilizers and antioxidants, plus carbon black in dark-colored bins. These additives slow UV degradation and oxidation, which are major causes of surface cracking and color fading. For some products, impact modifiers and carefully controlled fillers are used, but the filler level must be balanced because too much mineral filler can reduce toughness. Wall thickness, rib design, corner radii, and gate placement are also engineered to minimize molded-in stress and thermal stress.

Every batch is checked for melt flow index, density, impact resistance, and color and UV additive dispersion. Finished bins may be tested under outdoor exposure and heat-cycle conditions. So the practical answer is: our trash can factory uses UV-stabilized HDPE blended with LLDPE, supported by antioxidants, hindered amine light stabilizers, and design optimization, to avoid cracking in hot weather.