The Comfort and Ergonomic Design of Nardi Chairs
https://www.scribd.com/document/1005612912/The-Best-Brands-for-High-Quality-Resin-Furniture-137296
The plastic fundamentally starts with most often a commercial-grade plastic, most commonly PP or structural polyethylene, yet major high-volume companies guard their proprietary mixes the way cola giants hide their syrup recipes