Patent ID: 7195804

Claim:
A composite paperboard structure comprising a backing structure adhered to a paperboard layer, said backing structure consisting of: a) an oriented polymer film layer; b) a thermal bonding polymer layer adjacent and substantially coextensive thereto, said thermal bonding polymer layer having a thickness between 10% and 40% of a combined thickness of the oriented polymer film layer and the thermal bonding polymer layer; and c) a reinforcing scrim polymer layer adjacent and substantially coextensive with the thermal bonding polymer layer; wherein the oriented polymer film layer, the thermal bonding polymer layer, and the reinforcing scrim polymer layer each individually comprise a synthetic condensation polymer, the synthetic condensation polymers each comprising, in polymerized form: 1) a) a carboxylic acid or a mixture of carboxylic acids, and b) either i) a diamine or a mixture of diamines, or ii) a diol or a mixture of diols, or 2) an ω-amino acid having more than 2 carbon atoms, or a mixture of such amino acids, wherein, for the backing structure taken as a whole, at least 90 mol % of a combined total amount of the carboxylic acid or the mixture of carboxylic acids in the synthetic condensation polymers is the same carboxylic acid, at least 90 mol % of a combined total amount of the diamine or the mixture of diamines in the synthetic condensation polymers is the same diamine, at least 90 mol % of a combined total amount of the diols or the mixture of diols in the synthetic condensation polymers is the same diol, and at least 90 mol % of a combined total amount of the amino acid or the mixture of amino acids in the synthetic condensation polymers is the same amino acid.