TekNational, Inc.
Tek-Sil® GP5X Series
If you need a gap filler with higher thermal conductivity, Tek-Sil® GP5X is rated at 11 watt/mk compared to 1.5 watt/mk for the standard "GP" material.  This material is presently available in five thicknesses. 
GP5X SeriesUnitGP5X-15GP5X-20GP5X-40GP5X-60GP5X-79
Thicknessmm0.300.501.0 +/-0.21.5 +/-0.22.0 +/-0.3
Widthmm200200200200200
Lengthmm300300300300300
Thermal Resistance°Cin²/W0.130.170.260.360.47
ColorvisualGray
Thermal Conductivitywatt/m-k11
Volume ResistivityMohm·m7.0x10³
Withstand VoltagekV/mm·AC11
Specific Gravitygr/cm³3.3
HardnessShore OO64
Elongation%40
CompressionKgf/in²@10%245810099113
50% sustain after 1 min120201197192183
Continuous Use°C-60° to +200°
Flame RetardanceUL 94VV-0