PolyOne offers three types of blow molding machines: monolayer, trilayer and stretch. Monolayer machines process polyethylene, polypropylene and rigid polyvinyl chloride (PVC). Tri-layer machines mold polyethylene and polypropylene and offer three full layers of plastic for enhanced barrier protection. Stretch blow molding machines mold polyethylene terephthalate. More info: Website: www.polyone.com.