No, it is thermal insulation. It works on the basis that acoustic waves in the underlying material do not couple to the isolating layer because of a mismatch in acoustic impedance. It is the same as sound waves in air reflect off of a concrete wall with little coupling to the wall (which is why it is hard to here a conversation on the other side of a wall that you could clearly hear just a few inches away in air on the other side of the wall. Likewise vibrations in a solid material do not couple well to the air.
Thermal waves in solid materials are just a random jumble of small amplitude incoherent sound waves in the material