Method of forming a heat resistant carton

Abstract

A method of forming a heat-sealable carton having a pair of mating surfaces to be sealed includes the steps of coating at least one of the carton surfaces with a heat-activated thermosetting adhesive, spraying a fine mist of a water-based adhesive which exhibits high contact tackiness when dry, to form a discontinuous film on the coated surface, heating the water-based adhesive coated surface to a temperature sufficient to dry the water-based adhesive and activate the thermosetting adhesive, placing the mating carton surfaces in contact with each other and applying pressure for a time sufficient to seal the contacting surfaces together. A carton formed by the method is provided with flaps sealed by the combination of thermosetting heat-activated adhesive and high tack water-based adhesive. This allows the mating surfaces to be rapidly sealed by automatic carton closing apparatus and results in a sealed carton which exhibits good seal integrity at high temperatures. A carton formed in this manner is useful, for example, as a food container which can be placed directly in an oven to heat the contents thereof, with the carton seal being unaffected by the oven heat.

Dependencies are inferred from the claim text.