MH&W’s DAPCM80 is a combination of hot melt waxes optimized with special packages to improve thermal conductivity while maintaining the high Heat of Fusion.
The wax mixture in DAPCM80 melts at a nominal 80°C. Users measure various temperatures depending on the dimensions of the block and the position of the melt plane in time. The material is optimized for transient absorption of heat loads in electronic enclosures over a 6 to 24 hour period of exposure. Typical application is in passive Natural Convection cooling of electronic enclosures exposed to daily sunlight heat peaks. The material melts to absorb heat during daylight hours and refreezes during cooler night hours.
Provision for up to 10% volume expansion on melting must be provided.
- Does not depend on crystalline hydration. No nucleation or segregation issues
- Unlimited number of freeze-thaw cycles
- Repeatable performance w/o degradation
NEMA 12 Enclosures
Property Symbol Unit DAPCM80-1 DAPCM80-2 Color white black Compound filled
Thermal Properties Melt Temperature Rth °C 79.5 – 86.1 79.5 – 86.1 Heat of Fusion Rti kJ/kg
Thermal Conductivity λ W/mK 0.08 0.2 Specific Heat (solid) Cp kJ/kg°K 2.0 2.0 Specific Heat (liquid) Cp kJ/kg°K 2.9 2.9 Electrical Properties Breakdown Voltage Ud;ac kV/mm > 1.0 > 1.0 Dielectric Breakdown Ed;ac kV/mm > 5.0 > 5.0 Mechanical Properties Density Kg/M3 800 800 Penetration @ 25°C ASTM D1321 15-22 15-22 Viscosity @ 100°C SUS 75 75 Flash Point °C 277 Min. 277 Min. PH on H2O insoluble Non-corrosive Non-corrosive
Material melts and must be contained to be used effectively. User must control material thickness to achieve effective transient cooling.
Typical packages include heat sealed Polypropylene cylindrical tubes, vacuum formed polypropylene housings, custom fabricated metallic housings or multilayer pouch envelopes.
Preferred method of packaging for use is in pouches. Multilayer pouch material consists of mylar outer layer for strength, aluminum foil middle layer to control gas permeation and polypropylene inner layer for hermetic sealing.