What Is PVC Anyway?

Unless you’re a scientist, engineer, or deal with a product that is made from PVC, you may have no idea what these initials stand for.

Well…it’s polyvinyl chloride, also known as vinyl. PVC is the most widely used plastic in the world. It can be rigid like pipe and window frames or flexible when used in blood bags, toys, or the Duro-Last membrane.

Vinyl comes primarily from two simple ingredients: fossil fuel and salt. In the United States, the fossil fuel used to produce vinyl is typically natural gas. Natural gas goes through a refining process to make ethylene. Rock salt goes through electrolysis to separate the chlorine element for use. The entire process occurs in a closed-loop system that is tightly controlled and monitored.


Ethylene and chlorine are combined to produce ethylene dichloride which is further processed into a gas called vinyl chloride monomer (VCM). Through polymerization, the VCM molecule forms chains to become a white powder (vinyl resin) which is the basis for compounding with additives such as plasticizers for flexibility, stabilizers for durability, or pigments for color. Chlorine (Number 17 on the Periodic Table of Elements) is one of the most abundant naturally occurring elements on earth. The chlorine component gives vinyl some of its natural fire resistance.

The vinyl film used to make the Duro-Last roofing membrane is laminated to a weft-inserted polyester scrim. The proprietary blend of components in the film combined with the scrim impart the characteristics that make the Duro-Last membrane the “World’s Best Roof”®.

In our next blog posting, we will discuss more of the characteristics of PVC and how it is unfairly labeled “environmentally-harmful” by many environmentalists.