Archives for March, 2010

Introducing Keratherm KL 90 and KL 91

Mounting Tape Provides up to Three Times the Thermal Conductivity of Competing Tapes

MH&W International has introduced Keratherm® KL 90 highly thermally conductive, double-sided adhesive tape which provides 1.4 W/mK of thermal conductivity – nearly three times higher than other thermal tapes – for more effective heat transfer from hot components to heat sinks. The new tape’s thermal impedance is just 208°C-mm2/W (0.32°K-in2/W).

Keratherm KL 90 tape consists of a ceramic-filled acrylic adhesive film that provides exceptional bonding properties, and replaces the use of mechanical fasteners, reducing costs and assembly time. A fiberglass-reinforced version, KL 91, is available for applications requiring higher levels of ruggedness, peel strength, and conformability to irregular surfaces. Both Keratherm KL 90 and KL 91 mounting tapes are silicone-free, eliminating any contamination concerns. If necessary, the tapes can be cleanly removed using a thin-edge blade.

Keratherm KL 90 double-sided adhesive tape is supplied on 400 mm (15.75 in) wide rolls, and is also available in custom die-cut shapes. Its standard material thickness is 0.300 mm, (0.012 in). KL 90 tape pricing starts at $0.22 per square inch in high volume orders. Developed and manufactured by Kerafol, a world leader in thermal interface material innovation, complete information on Keratherm KL 90 thermal adhesive tape can be found at www.mhw-thermal.com.

U90 Silicone-Free Interface Material Provides High Thermal Conductivity

MH&W International has introduced Keratherm U 90 thermal interface material, manufactured by Kerafol, for use where contamination concerns prohibit the use of silicone-based thermal pads, but where high levels of thermal conductivity are needed for sufficient thermal transfer in hot electronic devices.

U 90 material consists of a ceramic-filled polyurethane film with thermal conductivity of 6.0 W/mK and thermal impedance of just 0.05 Kin2/W. The material has a high dielectric breakdown property of 20 kV/mm. It provides strong perforation protection with a tensile strength of 2.0 N/mm2 and a Shore A hardness of 70.

Typical applications for silicone-free U 90 thermal interface pads include medical devices, laser equipment, lighting systems, solar energy, disk drives and aerospace electronics.

MH&W’s Keratherm U 90 interface material is available in 0.1, 0.2 and 0.3 mm thicknesses (3.9 and 7.8, and  11.8 mil). Standard and custom shapes are available in continuous rolls for automated or manual application. Pricing for U 90 thermal interface pads starts at $0.25 for 1 inch square, 0.200 mm thick pads in high volume quantities.

U 90 silicone-free thermal interface materials are part of Kerafol’s Keratherm line of thermally conductive interface materials. More information on U 90 pads can be found at www.mhw-thermal.com or by calling 1-201-891-8800 for samples and quotes.

Choosing Thermal Interface Materials

Knowing Your Application Needs is Key to Picking the Best TIM

As component powers continue to grow, so do their cooling requirements. One rule of thumb says that for every 10°C rise of the junction temperature the failure rate doubles. Thus, there is an urgent need to remove heat from hot chips to the surrounding air stream. Demand has led to a variety of new thermal management systems. But nearly all of these continue to use thermal interface materials, or TIMS, to effectively provide heat flow across the mating interfaces of cooling systems.

The essential purpose of TIMs is to maintain effective transfer of heat from hot chips to dissipating devices such as heat sinks or spreaders. As heat flows, it encounters thermal resistances that impede overall heat transfer. TIMs reduce the most problematic of these, the contact resistance between the mating parts (heat source – heat sink). Air gaps significantly limit heat flow from the hot component into the sink or spreader. An effective TIM replaces the gaps created by the non-smooth mating surfaces with a material whose thermal conductivity is much greater than that of air. Basically, it replaces poor conduction from point contacts and air to enhanced conduction through solids.
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