Rheology of PVC Plastisol at Instability Region and Beyond (Proposal for Super-High Shear-Rate Coating)

The coating speed of plastisol is limited to a shear rate below the instability, because the instability results in nonuniform coating. However, there is an indication that beyond instability region the flow stabilizes again at the very high shear rates. If a plastisol is made to flow through the completely enclosed die-assembly with filled channel and let the instability taking place there, a super-high speed coating may be possible at the postinstability region. Although this work does not involve actual experiments, it explores possible mechanisms of flow at the instability and the stable flow beyond. The relation between the inter-particle interaction, (either attractive, repulsive, or neutral) and the flow type, (either clustering or nonclustering flow) is explored in order to aid designing a new device and developing formulations suitable for its use.