as the website is in Russian, either use google chrome to translate or look at (57) in the document which is the Abstract:

http://www.fips.ru/cdfi/fips.dll/ru?ty=29&docid=181944&ki=PM states the liquid is hydrophobic inert silicone as a coolant liquid with a kinematic viscosity of 5-200 mm at a temperature of 25 ° C with the addition of antistatic additives