AbstractFor an understanding of the phenomenon of lubricant extrusion of Teflon tetrafluoroethylene resin under nonmelt conditions, a mechanism is proposed based on observed extrusion‐hardening and dependence of flow rate on extrusion pressure. These factors can be derived from expressions in which the maximum shearing stress is equated as the sum of two components, one proportional to the maximum shearing strain (strain‐hardening component) and another proportional to the strain rate. Thus, in turn, permits the derivation of an expression for the die pressure drop which is in agreement with the experimental data related to flow rate, die dimensions, lubricant concentrations, and time of extrusion. The analysis provides some insight into aspects of commercial extrusion, particularly in wire coating, with practical consideration of the critical nature of guide tip positioning and the effect of wire coating speed on die press
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