The global electro-chemicals manufacturer, Electrolube, has frequently been approached regarding the prospect of an optically clear, flame retardant resin. As the demand for LED encapsulation ever increases, particularly for hazardous areas, Electrolube has developed the long-awaited new UR5641 encapsulation resin.
Technically, UR5641 almost defies convention and is very different from other resins that claim to be flame retardant and transparent. Traditionally, in order to obtain the desired flame retardancy resin manufacturers have used solid fillers to achieve flame retardancy but such fillers simply do not permit a transparent resin when cured. Traditional liquid flame retardants tend to be halogenated, whereas Electrolube’s UR5641 does not contain any fillers and has the additional benefit of being halogen free.
Conventional resins that claim to be flame retardant and optically clear are actually a pale amber when cured. Many of these resins are most likely to be based on epoxy technology which are prone to yellowing. Electrolube’s UR5641 is based upon aliphatic urethane chemistry, which is naturally resistant to the yellowing effects of natural light, making it useful for both exterior as well as interior applications.
UR5641 cures to provide a flexible, protective and aesthetically pleasing covering over the luminaire elements. The resin also offers high resistance to weather, acids and alkalis, water and mould growth. UR5641 is a two-part, semi-rigid, optically clear, flame retardant polyurethane resin that meets the UL94 V-0 standard. Due to a carefully selected blend of components, UR5641 is an extremely durable, low viscosity system that can be used for a wide variety of applications. The new resin is eminently suitable for the protection of LED luminaires exposed to hazardous atmospheres, such as emergency lighting, or lighting intended for installation in ATEX rated/zoned environments.
The UR5641 resin demonstrates high dielectric strength at 11 kV/mm, excellent thermal conductivity of 0.35 W/m.K and provides a wide operating temperature range between -40 to +120 °C. The RoHS-2 compliant resin also provides a cure time within 24 hours at 23°C or 4 hours at 60°C.
Ron Jakeman, Electrolube’s managing director, comments: “We have been frequently asked over quite some time about a fully clear, flame retardant resin system, and saw an opportunity to provide a solution for the LED market, where our reputation for providing high performance, reliable chemistry solutions is growing considerably. Electrolube is fast becoming the go-to resource for specialist technical solutions that solve customers’ manufacturing problems and help them bring high-quality products to market faster. The UR5641 is a world-first product, genuinely offering a fully transparent, UL94 V-0 flame retardant solution to the LED market. We have now launched the product globally and are very excited about the feedback we are receiving from customers currently testing the resin.”