Patent ID: 8377548

Claim:
A multi-layer foamed polymeric article of manufacture, comprising: a non-laminated multi-layer thermoplastic material sheet having a crystallinity gradient, and first and second discrete outer skin layers sandwiching a plurality of discrete inner foamed layers, wherein the two outer skin layers and plurality of discrete inner foamed layers are integral with one another, wherein the outer skin layers have a crystallinity, and wherein the plurality of discrete inner foamed layers includes at least: (i) two substantially identical second inner foamed layers whose crystallinity is less than the crystallinity of the outer skin layers, and (ii) a centrally positioned third inner foamed layer whose crystallinity is less than the crystallinity of the second inner foamed layers, the third inner foamed layer being positioned immediately adjacent to and interposed between the second inner foamed layers, wherein: the three inner foamed layers are formed by foaming a single piece of the thermoplastic material and the thickness of each of the two second inner foamed layers is greater than the thickness of the centrally positioned third inner foamed layer.