Non-Silicone Thermal Pad or called Non-Silicone Based Gap Fillers are used to fill gaps of 0.1-10mm between surfaces and lower thermal resistance by excluding air from the interface. These materials are used when the presence of silicone oils could be detrimental to product performance.
On the other hand, Non-Silicone Thermal Pad are still generally used under compression of approx. 25-40% as Silicone Based one which helps to reduce pressure to electronic components.
This kind of material usually used in Telecommunications and Medical Market due to their special demands.