Patent ID: 7074466

Claim:
A thermally insulating beverage or food container, comprising: (a) a bottom wall; and (b) a side wall extending upwardly from the bottom wall, said side wall comprising (i) a substrate layer comprising paperboard, (ii) an expanded foam layer having a projected area and defining a remote surface thereof, remote from said paperboard substrate layer, the remote surface of said expanded foam layer being defined by intermingled peaks and valleys, the peaks of the remote surface representing about 25 percent to no more than about 65 percent of the projected area of the remote surface, and (iii) a heat seal layer comprising a polymeric film defining the inner surface of said beverage or food container, said expanded foam layer being disposed between said paperboard substrate layer and said heat seal layer such that said expanded foam layer is not exposed as a surface of said food or beverage container and said heat seal layer defining a barrier between said expanded foam layer and contents of said beverage or food container, said expanded foam layer being in contact with said paperboard substrate layer, said heat seal layer being affixed to the remote surface of said expanded foam layer only at and adjacent the peaks, whereby thermally insulating dead air space is defined between the remote surface and the heat seal layer at the valleys.