Like all silicones, Liquid Silicone Rubber (LSR) is characterized by a flexible, fully saturated backbone of alternating silicon and oxygen atoms. The siloxane bonds have a partial ionic nature and give the material its high strength. The backbone is shielded by closely packed hydrophobic methyl side groups, which have low intermolecular forces between them. This allows the surface energy or surface tension to be low, while also being hydrophobic. This characteristic enables liquid silicone rubber to be water repellent, while allowing it to adhere only to materials with higher surface energy such as polyamide 66 or polycarbonates.
Polycarbonate (PC), first introduced in 1958, is an amorphous engineering thermoplastic with exceptionally high impact strength, transparency, high temperature resistance, and dimensional stability. It has a high surface gloss and is available in many colors and color intensities. Additionally, it is impact resistant and maintains high strength and stiffness in a temperature range from -150 to +135˚C.