LED potting compounds expand their scope

The LED epoxy and polyurethane potting compounds are used in applications from specialised lighting to LED indicators that are incorporated into other products. From very high thermally conductive epoxy potting compounds to flexible polyurethanes that seal out moisture and contaminants over a large temperature range, ALH Systems can help to select the proper material for your LED encapsulation application. The ALH Systems NP1400 Range provides unfilled, transparent resin systems for potting, encapsulation and coating applications. The NP1480 polyurethane system is the workhorse of the range, and is available in 1:1 cartridges, twinpacks and bulk. The low mix viscosity (10 poise) and convenient gel time (15 minutes) make the NP1480 System easy to use. The UV stable NP 1480 resin has a Shore A hardness of 85 with an elongation of 150% providing a toughness and abrasion resistance suitable for most applications. The NP1482 PU system is a development from NP1480 offering a greater green strength for situations where areas of stress concentration from components might disrupt curing. The slightly longer gel time (25 minutes) allows volume cures. NP1482 retains the excellent UV stability exhibited by NP1480. The NP1483 PU system has been developed for doming applications. A higher viscosity with a lower surface tension creates a proud dome over substrates, with the 40 minute gel reducing the possibility of surface blemishes. The NP1483 PU system has improved adhesion to a wide range of substrates and the crystal clear finish is shown to not be affected in our weathering tests. The NP1483 system is available in cartridges, twinpacks and bulk. For many potting applications the lowest viscosity is required. The NP1484 PU system has a mix viscosity of just 4 poise, and cures with a little more flexibility (Shore A hardness of 80). This very clear, bubble free material is an excellent choice for LED potting. The NP1400 series also includes several epoxy systems for applications where polyurethanes fall short. The NP1433 decoupage epoxy resin provides a high gloss, chemically resistant, clear coating for a large range of applications. The NP1434 epoxy system is slightly flexible with a Shore D of 52 and cures with a relatively low exothermic temperature rise for an epoxy with a 30 minute gel time. It does have a slight colour but this does not significantly yellow with weathering. The very low water uptake (0.3%/30 days) has meant that the NP1434 system is the choice for LED indicators in marine applications and chemical environments. The NP1435 system has a low viscosity (3 Poise), low colour, and its enhanced adhesion makes this epoxy resin very suitable for LED encapsulation for use in chemical environments. Although the initial colour is light straw, our ongoing weathering tests have shown no degradation. The electronics and the power supplies behind the LED's require advanced resins for protection and to dissipate generated heat. ALH Systems have developed two products specifically to provide these qualities. The UL 94 V-0 approved NP1003 epoxy system offers an internationally recognized solution to many power supply problems. The water uptake is minimal (0.1%/ 30 days) and the slight flexibility makes NP1003 useful in most outdoor applications. The thermal conductivity of 0.9 W/m/OK and low expansion coefficient (40 ppm/OC) provide the necessary performance for LED power supplies. Many LED displays on metering systems have employed the NP1004 polyurethane system for the encapsulation of the electronics. This easily machine dispensed resin has excellent high voltage properties (20 kV/mm electric strength) and the low mix viscosity (14 poise) prevents any air entrapment during potting. The flexibility of the cured resin allows its use in most environments. The NP1025 epoxy system provides state of the art thermal conductivity of over 1.3 W/m/OK from a liquid mixed resin that has a viscosity of just 20 poise. The long (1 hr) pot life allows users to further reduce this initial viscosity (to 1 – 2 poise) prior to use, by warming the resin. The penetration and wetting of substrates with this high thermally conductive mix has allowed component manufacturers worldwide to push on the performance boundaries of their design. This epoxy resin system further provides superior electrical properties (15 kV electric strength), high flame retardancy, low cure shrinkage and thermal expansion coefficient (0.3% & 30 ppm/OC respectively). Two new additions to the range of adhesives are specifically for LED applications. The NP2001 water clear rapid adhesive has performance characteristics comparable to most 5 minute epoxies but offers the additional property of being very clear. This cartridge dispensed resin is easily applied. The NP2004 clear instant adhesive employs radical new technology to obtain an almost instant adhesive bond with a high build resin. The cartridge dispensed NP2004 system is UV stable and offers a non-yellowing adhesive for outdoor use. Readers can see more of the ALH Systems range by visiting the FAST Exhibition at the Williams Conference Centre on September 10th, 2014. Follow the links to register.