7 ms·

There is still glass (and silicone?).

• xxs 2y ago
  glass is a lot heavier and way more expensive (glass is made out of silicon). There are a lot of different types of plastics the common ones use in packaging are LE-PE (light density polyethylene) and PP (polypropylene). They are both thermoplastic, they melt then heated. Silicone is also a form of plastic, it's thermoset (it chars effectively and it doesn't melt) - and it's awfully expensive. There are other plastic, e.g. nylon (PA6) that are still expensive but much cheaper than silicone.
• mrob 2y ago
  Silicone rubber has high gas permeability. This makes it good for contact lenses, but bad for food packaging.