We don’t use recycled grind in our PVC vinyls. Everything is 100% pure, so Simplex strip doors last longer without yellowing or cracking. Strip curtains are shipped flat in reinforced boxes. They hang straight and true the first time without curling. Simplex also offers materials for special applications, including FDA-approved low temperature PVC strips for freezer applications, and PolySim, a thermal plastic urethane that has permanent anti-static properties and meets ASTM E-84 standards and is Class 1 fire rated, with the lowest smoke ratings of any clear material on the market.