Rigid PVC Compound: PVC Dry-Blended with Lead Stabilisers and Lubricants

PVC resin alone cannot be extruded into pipe: it needs a heat stabiliser, lubricants, a filler and a pigment. This is the pipe compound AlliedSignal's patent US 5,426,144 (1995) used as its 'currently used' comparison (Comparative A): 100 parts PVC with calcium carbonate, titanium dioxide, tribasic lead sulfate, lead stearate, paraffin and stearic acid, blended in a high-speed mixer. Our heads stand in for the patent's trade grades. Lead stabilisers are poisonous: no dust. The picture: our diagram.