One purpose is, in an icemaker inside your refrigerators freezer, to provide 'thermo-couple' between the ice cube mold and the thermostat, such that the thermostat senses the temperature of the mold accurately, thereby causing the electrical cycling of the heater, which heats the mold only enough such as the ice cubes can be easily ejected from the mold. It's a putty-like substance that is available in a tube.
~A Nonna Muss