Method and apparatus for microcellular polymer extrusion

A method comprising:

• establishing a first stream of a fluid, polymeric material;
• admixing the first stream with a blowing agent to form a single-phase solution;
• continuously nucleating the solution by dividing the stream into separate portions and separately nucleating each of the separate portions;
• and
• recombining the at least two portions to form a recombined stream of homogeneous nucleated, unfoamed fluid polymeric material.

A method comprising:

• establishing a first stream of a fluid, polymeric material;
• admixing the first stream with a blowing agent to form a single-phase solution;
• continuously nucleating the solution by dividing the stream into separate portions and separately nucleating each of the separate portions;
• recombining the at least two portions to form a single, recombined stream of nucleated, fluid polymeric material;
• subjecting the recombined stream to conditions of elevated pressure sufficient to limit growth of cells and to prevent final foaming of the material;
• and
• shaping the recombined stream into a desired shape while lowering pressure applied to the stream to a pressure allowing final foaming of the material.