Why are plastic lids usually made of PP?
Polypropylene (English abbreviated PP) is an odorless, tasteless, non-toxic, white translucent plastic and chemical properties are very stable, heat resistance, rigidity and high yield strength and high density polyethylene, good toughness, the price is cheap, the injection nozzle, the bottle manufacturing process better.
PE is ok too. Most bottle caps are HDPE, hdpe.If it is pure PE, pure PE bottle cap than pure PP soft, and no PP anti-aging, from this point of view, or PP material better!
Of course, high density polyethylene (abbreviated HDPE) is also possible, but its rigidity and heat resistance are slightly worse, anti-aging properties better than polypropylene
