Polypropylene is a tough but lightweight, rigid and crystalline thermoplastic polymer also referred to as PP, or just no. 5 (which is the resin identification code), with excellent heat-resistance qualities.
Polypropylene is one of the top three widely used polymers today, extremely common in several household products and consumer goods applications, including baby bottles. It doesn’t react with water, detergents, acids, or bases, so it won’t break down easily. It’s quite durable, so it withstands daily wear and tear.
Polypropylene is considered safe for reuse and is now accepted by most curbside recycling programs. It can be melted and reformed into plastic pellets that then are used to make new products.
To further ensure your safety, 24Bottles uses only BPA-free and phthalate-free polypropylene in parts of some lids and caps.