Bakelite was the first type of plastics material to be made artificially. The resin is usually mixed with a 'filler' of non-plastics material, which is added as a powder or in a fibrous state. So-called ‘wood-flour’ fillers give more brittle mouldings, which crack readily under shock loads or impact. Cotton or shredded fabric fillers give tougher mouldings, whilst asbestos fillers can be used to produce heat-resistant mouldings.
The material has a tensile strength of about 45 N/mm and a compressive strength of about 150 N/mm2. Its electrical resistivity is about 106 Ωm and its dielectric strength is about 10 MV/m.