Importance

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Abstract

An inexpensive, disposable, three-dimensionally contoured container, suitable for many purposes including holding food during exposure to high temperatures for long times in either a microwave or a conventional oven without any detrimental effect to the container or the food. The container consists of an essentially impervious liner of polyethylene terephthalate directly bonded by its own substance to a pre-formed contoured base obtained by molding to final shape nonbrowning substantially 100% bleached kraft wood pulp from an aqueous slurry thereof against an open-face suction mold, and drying the same under pressure imposed by a mating pair of heated dies. The liner is formed by bonding to the pulp base a 0.5-2.0 mil thick film of thermoformable, substantially amorphous, substantially unoriented polyethylene terephthalate having a molecular weight which is understood to be in excess of 15,000. The film is bonded to the base by pre-heating the base, rapidly pre-heating the film and then quickly pressing the film into contact with the base at a temperature in the range of 300.degree.-375.degree. F., the pressing being done by vacuum in the range of about 20 inches of mercury applied through the base for no longer than about 1 second, and finally cooling so that the liner thereafter will not shrink-separate away from the contoured base as a result of subsequently exposing the container to a temperature of up to 400.degree. F.

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First Claim