초록 ▼

Disclosed herein is an improvement in microcellular or supermicrocellular polymer extrusion systems. Both conventional and microcellular systems employ an extruder which plasticates polymer pellets into a polymer melt; a gas metering system, whereby a gas is injected directly in the polymer melt flo

Disclosed herein is an improvement in microcellular or supermicrocellular polymer extrusion systems. Both conventional and microcellular systems employ an extruder which plasticates polymer pellets into a polymer melt; a gas metering system, whereby a gas is injected directly in the polymer melt flow in the extruder; a mixing and homogenizing section of the extruder, which creates a single-phase solution of the polymer and the gas; and a nucleation device at the outlet end of the extruder. In this invention, the improvement to the conventional system comprises the nucleation means attached to said extruder which is a gear pump acting as a throttle rather than a pump. With this improvement, the discharge pressure is dictated by die resistance and flow rate as delivered by the gear throttle, and the pressure drop of the polymer/gas single-phase solution is nearly instantaneous.

대표청구항 ▼

[ What is claimed is:] [1.] A method of producing supermicrocellular polymer foams comprising forming foamed polymers with average cell sizes of less than about 0.05 .mu.m by extruding a single-phase solution of a polymer and a gas through a nucleation device associated with an extruder, wherein the

[ What is claimed is:] [1.] A method of producing supermicrocellular polymer foams comprising forming foamed polymers with average cell sizes of less than about 0.05 .mu.m by extruding a single-phase solution of a polymer and a gas through a nucleation device associated with an extruder, wherein the nucleation device is a gear pump acting as a throttle nucleator.