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60 The PCB Design Magazine • March 2017 CASTING A SPOTLIGHT ON RESIN APPLICATIONS projects undertaken for a couple of prominent international market players. The French company Odeli (On Demand Lighting) is a young, dynamic company who provide specialist bespoke LED lighting solu- tions. They contacted us after receiving an ur- gent lighting contract for an outdoor sports sta- dium. They required a resin to encapsulate their design as quickly as possible; it had to protect the LEDs from the environment (rain, wind, dust, etc.) yet be suitable for use in their produc- tion process. There were also aesthetic consider- ations, and a diffuse light was required. The use of a hazy resin can give a diffuse light due to the particles inside the resin causing the light to be scattered, rather than being emitted as a single continuous beam. It was for just this sort of application the UR5635 was developed. The timeline for the project was tight as there were only three months from the awarding of the contract to the open- ing of the stadium, which was for the European Games in Baku, Azerbaijan. We were able to sup- ply samples the next day so that they could com- plete their own four-week test program. Working with Odeli, we could meet their requirements both in terms of product performance, but also to supply the resin for production within a three- week delivery slot, in fact we delivered the re- quired material ahead of schedule. Once we had full specifications and an ex- planation of requirements with regard to the encapsulant for the stadium lighting, we invit- ed Odeli to carry out some tests on the UR5635 transparent hazy polyurethane resin based on the real conditions in which the lighting was destined to operate. UR5635 was duly tested and approved for the application, and the appropri- ate processes installed, all within one month of our preliminary meeting. Odeli required large quantities of resin for this project and fortu- nately we were able to satisfy that demand at short notice, which went a long way to helping them meet their rather tight deadline. UR5635 is a two-part, semi-rigid resin mate- rial formulated with a hazy/cloudy appearance. The product is ideal for decorative applications that need environmental protection, and is par- ticularly suitable for lighting applications where there is a desire for a dispersive lighting effect. As for the Odeli project, it achieved the desired effect, producing an excellent level of luminos- ity combined with a very pleasing aesthetic fin- ish. When the 6,000 athletes from 50 countries were performing at their peak in Baku, our res- ins were likewise performing well in illuminat- ing their achievements. As previously mentioned, the use of LEDs has opened a world of different possibilities for designers as to how to use lighting in different ways. Our Indian colleagues had an urgent call from Rockforest Technologies India, who were looking for a potting resin to protect a decora- tive strip lighting for outdoor use in a shopping mall complex. The company not only needed to meet a very tight project deadline but also achieve a specific "neutral white" (4,000K) co- lour from the lighting, and there was little or no room for manoeuvre on this. In addition, the material had to cope with both outdoor condi- tions as well as the footfall of pedestrians, as the lighting was planned for installation at ground level under a walkway. No pressure then! Our Indian office jumped into action and conducted some initial trials, potting the strip luminaires to the specified depth of 5.5mm us- ing our UR5634 semi-rigid, optically clear poly- urethane resin which, being highly UV resis- tant, is especially useful as an encapsulant for applications exposed to direct sunlight. Unfortunately, the resin caused a colour shift from the specified 4,000K (neutral white) to "cool white" (6,500K). Rockforest was un- der considerable pressure to solve this problem; " The use of a hazy resin can give a diffuse light due to the particles inside the resin causing the light to be scattered, rather than being emitted as a single continuous beam. "