Low surface roughness thermal interface device based on graphite with branched siloxane having high through-plane thermal conductivity

A low surface roughness anisotropic thermal interface device comprising:

• plural aligned thermally anisotropic conductive composite layers having a first thermal conductivity in a first direction and a second, larger thermal conductivity in a second direction, the aligned thermally conductive composite layers extending substantially parallel to each other in the first direction;
• each of the thermally anisotropic conductive composite layers including 70-95 weight percent thermal filler, wherein the thermal filler includes macro graphite flakes in an amount from 45-95 weight percent, the graphite flakes having a size of approximately 0.5 mm to 1.0 mm, the graphite flakes being aligned in the second direction approximately perpendicular to the first direction such that x-y planes of the flakes align in the second direction having the second, larger thermal conductivity, the thermally anisotropic conductive composite layers having a binder including a linear siloxane and a branched siloxane, the binder having a total weight percent of approximately 5 to approximately 25 weight percent;
• the thermally anisotropic conductive composite layers being adhered to adjacent thermally anisotropic conductive composite layers to create a laminated anisotropic composite thermal interface device;
• the anisotropic thermal interface device having an arithmetic average surface roughness of approximately 5 to 20 μm and a tensile strength of approximately 50 to 130 KPa and a thermal conductivity of 25 to 45 W/mK.