The purpose here is to use talc as a dusting agent for lubricating moulds and for preventing surfaces from sticking together during manufacture. Chemical inertness, platy structure and smooth greasy feel are the main criteria. As it is used in the form of dust, fineness of size is obviously important and grit is highly objectionable. The platy structurehas a smoothening effect on the surface of rubber tyres.
Talc is organophilic in nature: 1- fills up any gaps within the polymer chains. As a result, it improves mechanical properties of rubber like tensile strength, toughness and resilience.
Talc reduces permeability of gas through the rubber.
The micro-crystalline molecular structure of Talc is flexible. Hence, it maintains the elasticity of rubber even under high load and provides compression resistance.
Talc reduces electrical conductivity of the final product. Thus making the rubber covering on electrical cables, safe for handling by bare hands.