Polypropylene is a thermoplastic that was first created in 1954. From consumer goods (like reusable bags!) to automotive, and even furniture, polypropylene is one of the top 3 polymers used today! Not surprisingly, it’s also one of the cheapest plastics, which is why so much is made from it, including reusable bags!
*Fun Fact: the chemical formula for polypropylene is (C3H6) n. Go ahead…wow your friends! *
There are two main types of polypropylene available: homopolymers and copolymers, but if you’re not a chemist or involved in manufacturing, you likely don’t care. But if you do, ask Siri or Google. They’d love to help!
What is of importance here is that we use two types of polypropylene material in our reusable bags: woven and nonwoven. Woven polypropylene is composed of these polymer fibers woven together perpendicularly to make sheets. Nonwoven polypropylene takes those fibers and presses them under heat to create a sealed sheet. Both materials are strong, but woven polypropylene has an edge, which is why you’ll see it used to make packaging that encases very heavy items at a low cost, like sandbags.
And don’t forget, when comparing polypropylene bags, make sure to look at the construction (heat sealed seams versus stitched–the latter is much stronger) and the grams per square inch (GSM). The higher the GSM, the thicker and stronger the bag.
Polypropylene is so popular! What else is made from it? Some common uses of polypropylene that you may never have realized include:
- Disposable diaper tabs/closures
- Car bumpers, interior trim, and instrument panels
- Rope and twine, especially marine applications
- Disposable syringes and vials
Can polypropylene be recycled? Yes! To recycle polypropylene, the material is melted at a very high temperature to get rid of contaminants. Recycled polypropylene can be blended with virgin materials at up to 50%. Most reusable bags, however, contain only up to 20% recycled content.