Polypropylene Folding Crate (52.8 Qt) Polypropylene (PP) wygplastic.com Close Up of a Two Stacks of Blue Plastic Polypropylene Granules on a 3 Types Of Polypropylene Plastic You Should Know. This durable commercial container box is used for transporting goods. It folds compactly when not in use and does not slip when stacked. It has an opening window on the side so you can access your items from the side. It is an environmentally friendly storage item made with over 30% recycled polypropylene. User Guide (PDF: 1. 64MB)