MH&W’s Keratherm U 90 thermal interface material is a ceramic-filled polyurethane film with a thermal conductivity of 6.0 W/mK and thermal impedance of 0.05 Kin2/W. A lower cost version, Keratherm U 80, also silicone-free, provides 1.8 W/mK of thermal conductivity and 0.11 Kin2/W of thermal impedance.
Both TIMs are available with a light tack adhesive to keep them in place during assembly or pre-attached to heat sinks. The light tack adhesive can be compared with adhesives used on repositionable notes. The TIM pads won’t be damaged when removed from mounting surfaces, which is a common problem when stronger adhesives are used.
The U 90 TIM with adhesive is available in thicknesses of 0.125, 0.225, and 0.325 mm; U 80 is 0.175 and 0.325 mm thick. Both TIMs are available on roll stock or custom shaped pads.