US Patent 11951667 Extruded tubular films and processes for manufacturing tubular films

A process for manufacturing a tubular film such as an edible casing film or a packaging film. The process includes the steps of providing a preblended powder composition containing a polymer matrix, a plasticizer, and water; feeding the preblended powder composition to an extruder; heating the preblended powder composition to a temperature above 100 degrees Celsius for a sufficient time to fully hydrate the polymer matrix and to convert the powder composition to a flowable mass; and extruding the flowable mass through a tubular die of the extruder to form the tubular film. The tubular film comprises: about 40-75 wt % polymer matrix; about 10-35 wt % plasticizer; and about 10-35 wt % water. The polymer matrix component is fully hydrated under the temperature, pressure and shear conditions inside the extruder, and may have a component which is only fully hydrated at temperatures above about 100 degrees Celsius.