Highly transparent, UV and heat-resistant, yet flexible and injection-moldable - these are the characteristics of the new, heat curable liquid silicone rubbers (LSR) which supplement the range of established materials used in lighting applications.
With the rapid developments seen in recent years in lighting technology, the classic material - glass - is facing increasing competition from alternative transparent plastics entering into applications such as light guides, primary optics and lenses. This field is dominated by materials such as PC, PMMA, COP and PMMI, offering advantages in molding and high degree of design freedom, glass does not have. The injection molding process is the key to cost effective manufacturing, particularly in the case of high-volume production. Other advantages over glass are a less tendency to crack and a lower component weight. However, thermoplastics are also subject to application-related limitations such as temperature or UV-light resistance.
The new, highly transparent liquid silicone rubbers supplement the existing range of materials and offer special physical properties typical of a curing elastomer and these are described below next to possible applications.