Applications of Thermally Conductive Plastics in LED Luminaires

Thermally conductive plastics can be used to make LED components such as housings, heat sinks, substrates, reflectors, plug-in components, and other parts. In recent years, many plastics companies worldwide have developed a variety of thermally conductive plastics, most of which use engineering plastics and commodity plastics as the base material, such as PA, LCP, PPS, PET, PBT, PEEK, ABS, and PP. Ordinary plastics have a thermal conductivity of only about 0.2 W/(m·K); if thermally conductive fillers are added to the plastic, the thermal conductivity can reach roughly 1–20 W/(m·K), which is 5–100 times that of conventional plastics. RenJie Plastics is a well-known specialized manufacturer of thermally conductive plastics in China and holds a leading domestic position in the development and production of thermally conductive materials. Sales hotline: 18681139818; Contact: Tang Jihua.

1. Thermally conductive plastics can replace conventional aluminum in heat sinks

Thermally conductive plastics are lighter in density than aluminum — about half of it — so a plastic heat sink weighs only half as much as an aluminum one. Plastic heat sinks can be produced by injection molding, and the molding cycle can be shortened by 20%–50%. With a thermally conductive, insulating plastic heat sink, a non-isolated power supply can be used without worrying about safety. The only drawback of plastic heat sinks is their relatively high unit price, so at present they are not yet suitable for large LED heat sinks such as those in LED streetlights, but only for indoor low-power LED luminaires.

2. Thermally conductive plastics for LED luminaire housings

Plastics generally have a thermal conductivity of 0.14–0.34 W/(m·K) and are dielectric insulating materials. The U.S. company CoolPolymer developed thermally conductive plastics in 2000 and set up the first industrial production line; these materials are now widely used in electrical appliances, medical devices, aerospace, automotive, lighting, and laptop computers, after which plastics companies in various countries began producing thermally conductive plastics. When replacing aluminum with plastic for LED luminaire housings, the first consideration is that the selected plastic must have good heat-dissipation performance — that is, a high thermal conductivity — while also offering high strength. The engineering plastics used for LED lamp housings all have high melting points and excellent mechanical properties; this is because lamp housings have no heat-dissipation fins, so thin-walled housings are required to reduce the thermal resistance of the housing, and the plastics selected must have a high melting point, high modulus, and high strength, and must withstand repeated high–low temperature cycling tests.

Applications of Thermally Conductive Plastics in LED Luminaires

3. Other plastic components in LED luminaires

The plastic components in LED luminaires also include reflectors, handles, fastening parts, connectors, sliding parts, fan blades, operating parts, light channels, and so on. In addition to some engineering plastics, these components can also be injection molded from polycarbonate (PC), PBT, polyoxymethylene (POM), reinforced PP, and the like.