A CONTINUOUS EXTRUSION DIE FOR EXTRUDING A REACTIVE POLYMER MIXTURE

摘要

An extrusion die is described for extruding a polymer from a reactive precursor mixture without plugging of the die. The extrusion die includes a die inlet leading to at least one channel having dimensions which produce a wall shear stress value that exceeds the critical wall shear stress value for the particular reactive precursor mixture to prevent occlusion of the die. The preferred configuration of the die channels is a tree-like structure to obtain a coating width which is greater than the dimensions of the individual channels. Other features of the invention include a method for determining the critical wall shear stress value and a method for extruding reactive precursor mixtures.