About Vinyl & PVC

Vinyl, The Building Material

By many standards, vinyl is a new building material, first used broadly during and after World War II to meet many of the critical infrastructure and safety needs of that time. Yet vinyl blends many attributes of traditional materials with the advanced performance characteristics of today's - and tomorrow's - building products. Durability, light weight, solid environmental and fire characteristics, versatility and low maintenance requirements are just a few of the properties that have propelled the growing use of vinyl in the built environment.

Section Contents:

How is Vinyl Made?
Versatility Through Compounding
Tracing Vinyl's History

How is Vinyl Made?

Vinyl is essentially derived from two simple ingredients: petroleum and salt. Petroleum or natural gas 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). Finally, through a process known as polymerization, the gaseous monomer is converted into a fine, white powder - vinyl resin. However, one more step remains before the resin becomes a usable material.

Besides looking very much like flour, vinyl resin is analogous to flour. Both are of little use, by themselves. However, just as flour can be combined with other ingredients to make a moist cake, a flaky pie crust, or a variety of breads, vinyl resin can achieve various desired properties suited for a variety of end-products once it is combined with selected chemical additives and modifiers. The diagram below illustrates this process:
 
PVC production process

Versatility Through Compounding

Once the resin has been combined with these additives and modifiers, it is called compound. These additives dictate the needed performance criteria for each vinyl product, including color, flexibility, UV resistance and numerous other attributes. Vinyl can be made rigid and impact resistant enough for pipe or siding, or thin and flexible enough for wallcovering and upholstery. It can be made weather and heat resistant for outdoor uses such as fencing. For interior applications such as appliances or decorative products, vinyl can be clear or opaque or made to match virtually any color of the rainbow. With such versatility, vinyl is suitable for an almost limitless range of products, and every vinyl compound is manufactured with the needs of the specific end-use in mind.

Vinyl compound can be processed in a variety of different ways to become one of hundreds of different applications. For instance:

•Vinyl can be extruded, meaning that compound is heated and forced through a mold to form long lengths of product, such as siding, pipe or window profiles.

•Vinyl can also be injection molded into a hollow, three-dimensional mold to create electrical outlet boxes, exit signs or computer housings.

•Calendering produces vinyl film and sheet products in various widths and thicknesses for flooring, wallcovering or upholstery.

•Thermoforming uses heat to add shape to rigid PVC sheet, such as for shower trays or clamshell packaging.

•Products like vinyl bottles are manufactured through blow molding, which uses air pressure to force softened vinyl into a hollow mold.