The two main families of resins used to make solid surface are acrylic and polyester.
A purely acrylic-based resin yields a sheet that is thermoformable — that is, it can be heated, bent into a shape and cooled without any loss of performance. Another difference is that acrylics are less affected by ultraviolet rays present in natural light.
Polyester resins (including those which are mixed with acrylic resins) are used in many high-strength demanding applications other than solid surfacing, including outdoor application such as boats and aircraft cowlings. Some manufacturers and fabricators of polyester-based solid surface cite some thermoformability with these products, which are characterized by a deeper translucency.
Some products also now combine acrylic and polyester into their mix in an effort to capitalize on the properties of both of these resins. Both acrylic and polyester resins start life as petroleum, and thus their cost is tied at least indirectly to the price of oil. Of course other supply and demand factors enter in to make the chemical market extremely volatile price wise.
Every solid surface product contains additives. These include pigments for color, and a host of additives that improve or enhance chemical and performance
properties. There are UV absorbers, cross-linking agents, stabilizers and the list goes on. Every solid surface manufacturer changes the formulation and additives over time, carefully tweaking their products in a process of continuous improvement.
One important additive which all solid surfaces share is a catalyst. This is a chemical, usually peroxide, which causes the mixture to harden, or to cure.
Most high-volume solid surfaces are cast in sheets in a continuous process that uses conveyors to draw out the material. Sinks and other shapes cast the resin "syrup" into molds. It is important that no air bubbles be entrapped in the mix, as this would result in voids and weakening of the material. This is accomplished either by adjusting the viscosity of the mix, by vibration or by vacuum.
Curing allows the chemical reactions that form solid surface to be as close to 100 percent complete as possible, leaving a stable, inert material with all its performance properties intact. Some solid surfaces cure in the open air. Others cure by being bathed in steam or heated in ovens. Many polyester resins require "post-curing" operations, usually a heating-cooling cycle which increases the degree of cure. An improperly controlled cure can cause air bubbles in the material, effectively ruining it.