This invention relates to a method for producing transparent protective coatings on a substrate employing monomeric organosilicone compounds and oxygen using plasma enhanced chemical vapor deposition (PECVD) techniques.
Technology for improving the abrasion resistance of various surfaces, e.g., plastics, metals, etc. employing polymeric silicone compounds as a protective layer has been known for some time. Various PECVD processes have been developed but they all suffer from one or more defects. Some of the defects include cracking of the silicone compound coatings, delamination from the substrate surface and slightly colored coatings. Some of the coating techniques are also uneconomical, and some processes require that toxic materials be used. The resulting protective coatings are also sometimes not very abrasion resistant.
To overcome some of the defects, such as cracking, some PECVD organosilicone processes have been developed which require multiple steps thus driving up the cost of applying the coating (e.g., U.S. Pat. No. 4,927,704).
The present invention overcomes many of these problems to provide an adherent, very hard, non-cracking coating using a simple process scheme, requiring fewer steps. A thin plastic film substrate can be coated employing the principles of the invention, folded and creased without any substantial cracking of the coating.