ABSTRACT

This chapter is concerned with silicone release coatings. Silicones in many forms offer excellent release properties, but to present a nonstick surface and, at the same time, offer little or no transfer to the released surface, a cured filmic surface free from migratory species is required. The chapter discusses the ability to control the actual force required and the knowledge to accomplish. Most forms of silicones for the applications are oily in nature and progressively cure into a solid silicone rubber as a cross-linking reaction takes place. The basic functional component of a silicone release coating is a polydimethylsiloxane (PDMS) polymer. Homopolymers are chosen primarily for their rapid gelation and improved anchorage. Blends of homopolymers and copolymers are often used to optimize a balance between cure rate and anchorage. In tin-catalyzed solvent systems, the molecular weight of the PDMS chains used in forming the cured polymer network was the primary tool used to control release forces.