A heat insulating paper cup having an improved seal. The cup can include a body member having an inside surface and an outside surface, and a bottom panel member having a upper surface and a bottom surface. The body member is coated (or in some instances partially coated) on its outside surface with a foamed low density polyethylene, and on its inside surface with an unfoamed modified low density polyethylene. The bottom panel member is coated on its upper surface with a foamed or an unfoamed low density polyethylene or foamed or unfoamed modified low density polyethylene. The body member and bottom panel member are oriented and joined to form a heat seal at an interface between a portion of the unfoamed modified low density polyethylene coated on the inside surface of the body member and a portion of unfoamed low density polyethylene or unfoamed modified low density polyethylene coated on the upper surface of the bottom panel member.