US Patent 11179871 Microcellular foam sheet and processes of making and using

A solid state foaming process for generating a microcellular foam sheet for use in forming a container is provided includes a pre-foaming treatment phase prior to a solid state impregnation and foaming phase. The solid state microcellular foam sheet includes a central foamed section defining a foam layer within the microcellular foam sheet having a first population of cells within which are interspersed a second population of cells.