Raw Materials & Manufacturing
While vinyl is made from natural gas or petroleum, it is more than half derived from common salt, an abundant and inert natural resource. Worldwide, vinyl production accounts for less than 0.3 percent of all annual oil and gas consumption and about 10 percent of annual salt consumption.
The fuel is put through a process, called cracking, to make ethylene, which is combined with the natural element chlorine to produce ethylene dichloride. Another cracking process transforms ethylene dichloride into a gas called vinyl chloride monomer (VCM). Consistent with the vinyl industry's commitment to health, safety and the environment, emissions from this process have dropped significantly. From 1989 through 1996, releases of ethylene dichloride per one million pounds of vinyl produced dropped 88 percent, and releases of VCM per one million pounds of vinyl produced decreased by 63 percent.
Through a process known as polymerization, the gaseous monomer is converted into the fine, white powder that is vinyl resin. This process is closed, automated and high tech, and nearly all waste is recycled back into the system. Lifecycle analysis has shown that production of the vinyl polymer uses less energy than production of some other building materials. For example, research by Franklin Associates comparing the manufacturing processes for vinyl and aluminum windows determined that vinyl used about three times less energy.1
The resin is then compounded to produce tiny pellets the size of BBs. To make compound, the powdered polymer is mixed under heat with plasticizers, stabilizers, colorants and other substances to create whatever properties (rigid, flexible, clear, colored, etc.) are desired in the planned end product. An enormous range of properties are possible depending on the additives. The range of possible characteristics gives vinyl virtually infinite uses – not only in myriad building and construction products but also in medical products, electronics, trucks and automobiles, and other consumer products.
In the final step, fabrication, vinyl compound is melted and shaped into the desired end product. The most common processing techniques for vinyl building products are extrusion (pipe, siding, windows, fencing, decking), in which compound is heated and forced through a die to from lengths of the product, and calendering (flooring, wallcovering, roofing), in which compound is compressed through a set of rollers to form film and sheet of various widths and thicknesses.
Life cycle studies comparing the manufacture of vinyl building products and other building products have found that using vinyl saves an estimated 260 trillion BTUs per year – the equivalent of 44.2 million barrels of oil – over the highest energy-consuming plastic.
Cuttings and scrap from fabrication can easily be reheated and remolded. A study for the Vinyl Institute found that nearly all scrap generated during fabrication is recycled back into a finished product.2 As a result, nearly every vinyl product in use today contains some post-industrial recycled content.
"Comparative Energy Evaluation of Plastic Products and Their Alternatives for the Building and Construction and Transportation Industries," Franklin Associates, March 1991.
2"Post-Consumer and Post-Industrial Vinyl Reclaim: Material Flow and Uses in North America," Principia Partners, July 1999.