Rubber heat sink insulators

[sec]

In some commercial devices, I've seen power semiconductors that are insulated from their heat sinks by a grey, rubber-like insulator.

Does anyone know what this material is, how its thermal transfer properties compare to the classic mica washer/silicone grease combination, and where it can be obtained from?

 

[Yevgenip]

I've seen something similar on old CPU Heat sinks. It is like a sticky patch that transfers heat good. Now, they use thermal gel.

 

[ante1]

Hi Sec,

This is a silicone fabric sheet. Specially designed heat conducting glass fibre reinforced silicone rubber primarily used as electrically insulating inserts for power transistors and other semiconductor components, to replace previously used materials

View attachment 36349

 

[sec]

Thanks, that pointed me in the right direction. Some googling revealed that pre-cut insulators made out of this material go by the trade name 'Thermo-Pad', and sell for about US$1-1.50 for 5-packs of the most common shapes.