Rigid Thermofoil is a process that uses heat and pressure to bond a thin (8 to 16 mil) Polyvinyl Chloride (PVC) film to a substrate, typically medium density fiberboard (MDF). Since the film is so thin, it can bond to very intricate shapes. This allows for the creation of doors and drawers with raised panels, routed edges and other designs that can't be done with solid laminate.
Thermofoiling is a relatively new process for cabinets in comparison to laminates. Polyvinyl chloride was accidentally discovered on at least two different occasions in the 19th century. On both occasions, the polymer appeared as a white solid inside flasks of vinyl chloride that had been left exposed to sunlight. In the early 20th Century two chemists attempted to use PVC (polyvinyl chloride) in commercial products, but difficulties in processing the rigid, sometimes brittle polymer blocked their efforts. In 1926, a method was developed to plasticized PVC by blending it with various additives. The result was a more flexible and more easily processed material that soon achieved widespread commercial use.