The melt rheology of poly(vinyl chloride) (PVC) resin has been investigated as a function of shear rate over an 80°C temperature range. The microcrystalline nature of PVC has been observed in the form of a low activation energy (δEγ) L at low temperatures and a high activation energy (δEγ) H at high temperatures. The two distinct flow activation energies suggest different rheological flow units in the low and high temperature regions. It was possible to reduce the shear stress‐shear rate curves to a single master curve at 200°C by superposition of temperature and rate of shear.