Thermally conductive plastic lets designers breathe easier

Nylon-based Konuit, a thermally conductive compound from LNP Engineering Plastics, solved a critical heat-retention problem in a device used to help sleep-apnea patients breath easier. The motor's heat now escapes through its Konuit retainer plate and into surrounding air.

While developing a therapeutic sleep apnea/sleep-disorder breathing (SBD) device, designers at Australia-based ResMed (www.resmed.com) discovered the motor was overheating the unit's polycarbonate retainer. "The PC softened enough so that screws holding the motor to the retainer would loosen during testing," explains Geoff Crumblin, ResMed's production engineer. To better dissipate heat inside the unit designers turned to thermally conductive polymers called Konuit, from LNP Engineering Plastics Inc., Exton, Pa. (www.lnp.com). They are made from an array of polymers including nylon, polypropylene, polyphenylsulfone (PPS), and polyurethanes compounded with thermally conductive fillers. They reportedly have 10 to 50 times the thermal conductivity of traditional unfilled thermoplastics. ResMed designers needed to keep the breathing device as small and light as possible. But as the device grew smaller, dissipation and heat management became more critical. Designers chose a nylon-based Konduit over one based on PPS due to economics. "Now motor heat dissipates easily through the retaining screws to the retainer plate and out to the surrounding air," says Crumblin.