Parylene coating is a vacuum deposited coating that improves the longevity of silicone keypad artwork by up to ten times. Unlike polyurethane coating, Parylene coating is applied as a gas. The application process allows the parylene polymers to penetrate tight areas on the part, providing a uniform coating on all surfaces. 

Parylene’s thin, transparent and flexible characteristics enhance the performance of rubber and elastomer components by protecting surfaces and modifying surface properties. These improvements are made without degrading the functional performance of the part. Parylene yields a truly conformal coated part with a consistent thickness on both flat surfaces and around the internal dimensions of openings and features. The parylene coating also tends to improve the feel of the surface by removing the elastomer tack while protecting the keyboard against dirt and oils, and also protecting the printed nomenclature.