Polypropylene fabrics can melt when exposed to high heat. Using a press cloth with a cool iron is advisable.
According to this United States Patent Office document, when a new pure polypropylene fabric is ironed at temperature below about 100 C, wrinkles are not removed from the fabric. When ironed at temperatures between about 100 and about 119 C, the new fabric will crinkle if it is not subjected to tension or restraint. If the fabric is initially ironed at between about 120 and about 140 C, it becomes hard and shiny, which degradation is of a permanent nature and cannot be removed. Thus, it is evident that such a fabric may be easily ruined in an attempt to iron it.
Polypropylene feels like a wax paper towel, when used as textiles such as tote bags. It’s often used in coolers, tumblers, and water bottles due to its low heat transfer, meaning it’s a great insulator.
This material also floats and does not absorb water, making it an excellent choice for promotional materials that will be at the beach, pool parties, or other places where staying afloat and drying quickly are major assets.
See differences between polypropylene, polyester, and nylon below (thanks to QualityLogoProducts.com):
Polypropylene, Polyester, and Nylon: More Than You Ever Wanted to Know via kwout
Are You Ironing Wrong? Banish wrinkled shirts and rumpled sheets for good with RD.com's perfect-pressing tips.