Process for producing foam planks composed of ethylenic polymer resin, and foam plank produced in the process

摘要

Low density ethylenic polymer foam planks having density of from about 0.8 to about 1.9 pounds per cubic foot, dimensional stability, substantially closed-cell structure, a cross-sectional area of at least six square inches and a minimum cross-sectional dimension of at least 0.5 inch. Such foam planks are made from ethylenic polymers by release to lower pressure of flowable, foamable gel under pressure, e.g., by extrusion foaming, wherein the gel comprises at least one ethylenic polymer and at least one volatile blowing agent. The process of making such foam planks is particularly characterized by the improvement wherein the flowable gel is mixed sufficiently to disperse the blowing agent in the gel to an amount from about 13.5 to 35 x 10s moles per gram of the ethylenic polymer.