Lighting manufacturers are seeking the best options in light-diffusion technologies to offset harsh LED illumination, eliminate hot spots and maximize lumen output in optics and lenses. There are many ways to achieve diffusion, such as adding a diffusion film or texturing the surface of the plastic. Yet in some cases, these methods can either add cost or do not achieve the same aesthetics as other light sources.
To this end, Covestro incorporates precise engineered diffusion additives into Makrolon® polycarbonate resin. The pellets that are subsequently created can be injection molded into components or processed by extrusion into profiles, sheets and films. This “built-in” diffusion offers the advantage of eliminating a secondary operation that adds to system cost. Diffusion additives incorporated directly in the resin also allow for greater design flexibility in the molded shape, otherwise a secondary step may be necessary or may not be possible if the molded shape is complex.
Another aspect to consider with LED technology is meeting UL requirements. Since many LED lamp replacements and luminaires are considered electrical enclosures, meeting UL 94 flame retardancy requirements, such as stringent V-0 or 5VA ratings, is also necessary. Covestro has existing product solutions to meet these ratings and is developing next-generation products, which will meet these ratings at lower part thicknesses.
Molding or extruding parts with thinner wall sections is one way to reduce costs. To achieve this, the main thickness of a diffuser tube for LED lighting continues to decrease. A non-halogen flame retardant material is also requested by most lighting manufacturers. In terms of functionality, the balance of transmission (Ty), half-power-angle (HPA) and color are the key market requirements. Later in the second quarter of 2017, Covestro will launch a new non-halogen flame retardant (FR) Makrolon® polycarbonate extrusion grade with a UL 94 V-0 listing at 1.0 mm for a diffuser LED tube application.