PVC is made from a mixture of petroleum byproducts and salt (Worldwide vinyl production accounts only for about 0.3 % of all annual oil and gas consumption and about 10 % of salt consumption). Micro ingredients are added to achieve the desired properties of the finished material. The exact composition of these ingredients vary from producer to producer and are proprietary to every supplier. Some of the basic ingredients are: Heat Stabilizers: Heat Stabilizers are added to prevent material degradation during the extrusion process, increase the weatherability of the end product and allow the windows and doors withstand the effects of solar heating. Lack of heat stabilizers will make the product weak when exposed to the summer sun and can result in poor window operation or even total window failure. Processing Aids: Processing aids influence the melting and fusion through the extrusion process. They impart an elastic toughness to the material. Impact Modifiers: These ingredients improve the impact properties of the PVC profiles by reducing brittleness and increasing the pliability of the end product; without these modifiers, the profiles would be susceptible to cracking and breaking during the fabrication process, installation and operation of the windows. Lubricants: Lubricants improve the flow of vinyl through the dies during the extrusion process. They allow the surface of the finished product to be smooth and shiny. Fillers: The proper amount and type of fillers used in the formulation of the compound for profile extrusion is critical. Filler influences several properties of the final product, including impact strength, elasticity, shrinkage and last but not least, cost. Light Stabilizers: Light stabilizers are added to prevent fading. Fading is caused by the ultra violet light from the sun and results in a dull finished surface. Pigments: Titanium dioxide (TiO2) is the primary pigment in vinyl formulations. It gives the window profiles its brilliant white color and makes the product opaque. TiO2 aids in the reflection of UV rays, reducing heat build up and protecting the window from solar fading.