Resins or synthetic resins are industrially produced resins, typically viscous substances that convert into rigid polymers by the process of curing. In order to undergo curing, resins typically contain reactive end groups, such as acrylates or epoxides. Different types of resins are used by manufacturers with epoxy and polyester resins being the most common. These resins are prevalent in engineered quartz as they account for about 7-10% of the entire product. They are necessary as they are the glue for the crushed quartz and provide a maintenance-free surface.