Abstract: A domed container for the preparation and display of food includes a receptacle, a dome cover, and a hollow mold member. The receptacle has a bottom with a top surface and an outer circumference. The bottom possesses at least one groove in a closed, continuous pattern. The groove has two side surfaces and a bottom surface, and each side surface is configured to include projections extending into the groove. The dome cover includes a top wall having at least one wall depending therefrom. The depending wall has an outside surface and an inside surface. The container possesses a locking structure for releasably locking the cover to the receptacle. The hollow mold member, which forms a closed continuous pattern, has a lower edge that fits into the groove of the receptacle and is held in place from each side by an interference fit between the projections of the side surfaces of the groove and the lower edge, thereby removably attaching the hollow mold member perpendicularly to the receptacle.

Abstract: A polystyrene resin in foam form having a basis weight of less than about 20 g/100 in.sup.2 and a density of about 6 lbs./ft.sup.3 or less, the foam precursor of which is either a polystyrene having a melt index of about 8 or more or a polystyrene in combination with a minor proportion of any other material which will result in a melt index of about 8 or more. A method of forming such a polystyrene resin foam structure includes combining the resin in molten form under pressure with the blowing agent of at least approximately 100% carbon dioxide and extruding the mixture through a die into an atmosphere of reduced pressure to form the foam structure.

Abstract: A microwavable container useful in the microwave heating of items, particularly foodstuffs, comprises readily separable components. An outer shell which will remain relatively cool and, therefore, capable of being handled, is flexibly hinged to an inner shell capable of sustaining high temperatures. The inner shell rotatably folds about the flexible hinge in such a way that it is arranged in a substantially spaced relation to the outer shell and is releasably secured to the outer shell. The outer shell is made of a first microwavable polymeric material. The inner shell is made of a second microwavable polymeric material which is different from the first microwavable polymeric material. A consumer may heat a food product in the inner shell of the present invention without risking contact with that inner shell when the inner shell becomes hot. After use, the components are readily separable for separate recycling processes.

Abstract: A polystyrene resin in foam form having a basis weight of less than about 20 g/100 in.sup.2 and a density of about 6 lbs./ft.sup.3 or less, the foam precursor of which is either a polystyrene having a melt index of about 8 or more or a polystyrene in combination with a minor proportion of any other material which will result in a melt index of about 8 or more. A method of forming such a polystyrene resin foam structure includes combining the resin in molten form under pressure with the blowing agent of at least approximately 100% carbon dioxide and extruding the mixture through a die into an atmosphere of reduced pressure to form the foam structure.

Abstract: A microwavable container useful in the microwave heating of items, particularly foodstuffs, comprises readily separable components. An outer shell which will remain relatively cool and, therefore, capable of being handled, surrounds an inner shell capable of sustaining high temperatures. A consumer may heat a food product in the inner shell of the present invention without risking contact with that inner shell when the inner shell becomes hot. After use, the components are readily separable for separate recycling processes.

Abstract: A foamed thermoplastic article having an integral outer unfoamed skin layer is formed from a mixture of thermoplastic resin containing a blowing agent by removing at least a portion of the blowing agent in the die of the extruder. The blowing agent is removed, e.g., by modifying the die so that it incorporates a porous section whcih allows the blowing agent to be removed from the mixture.

Abstract: There is provided a three-ply plastic film prepared by a sandwich foam, blown film coextrusion process. The outer skin layers are composed of high performance polyolefins, such as linear low density polyethylene. The foamed middle layer imparts to the film improved structural integrity and stiffness, an independent tear mechanism for the skin layers, and improved TD tear strength.

Abstract: The properties of linear ethylene polymers, especially linear, low density polyethylene (LLDPE), are improved by adding a chemically modified ethylene polymer to the base resin. The modification is brought about by the use of a free radical generator, preferably an organic peroxy compound such as benzoyl peroxide, optionally with an unsaturated silane such as vinyl trimethoxy silane. The use of the modified resin masterbatch enhances the crystallization of the polymer and improves the melt strength of the polymer, providing greater bubble stability in the blown tubular film extrusion process so that higher operating speeds may be employed. In addition, the films produced from the blends have improved antiblocking properties without significant deterioration of mechanical properties.

Abstract: There is provided a 3-ply trash bag prepared by a sandwich foam, blown film coextrusion process. The skin layers are composed essentially of high performance polyolefins such as linear low density polyethylene. The foamed middle layer imparts to the bag improved structural integrity and stiffness, an independent tear mechanism for the skin layers, and improved TD tear strength.

Abstract: Disclosed are an apparatus and method for cutting and sealing a plastic film. The plastics film is conveyed to a sealing area which contains a sealing wire in a housing over which the plastics film is draped out of contact with the wire. The wire is preheated to a first temperature and is then heated to a second higher temperature while a differential pressure is applied to the film biasing it towards and into contact with the wire which cuts and heat seals it. By providing the heat sealing area in the outer periphery of a rotatable drum to which a continuous film is conveyed, a continuous cutting and heat sealing process can be achieved.

Abstract: There are provided coextruded two-ply laminate films in which one of the lamina is low density polyethylene and the other is a blend of 10-50 weight percent polybutene with 90-50 weight percent polypropylene or low density polyethylene. Such laminated films are tough and have good tear resistant.

Abstract: A method and apparatus are provided to continuously monitor and measure the average size of individual foam cells contained in a foam structure, such as polystyrene foam for example, as it is being fabricated. Such an arrangement permits the prompt adjustment of process conditions and/or the concentration of nucleating agents in the extrusion system in the event the size of the individual cells in the foam structure varies from a preselected standard.

Abstract: An apparatus and method for the determination of the flow properties of thermoplastic materials in admixture with volatile liquids or other additives comprising an extruder which is employed to melt the polymer and admix therewith volatile blowing agents or additives. Subsequently the molten mixture is injected into an extrusion plastometer or rheometer for extruding the mixture, while still in molten form, through a capillary orifice in the extrusion plastometer. When volatile liquid blowing agents are admixed with the molten polymer in the extruder, an adjustable linkage is provided interconnecting the plastometer and the extruder whereby the pumping rate of the blowing agent can be variably adjusted and the blowing agent positively injected into the molten polymer within the extruder by the reciprocal motion of a piston means employed in the extrusion plastometer.

Abstract: A method and apparatus are provided to continuously monitor and measure the average size of individual foam cells contained in a foam structure, such as polystyrene foam for example, as it is being fabricated. Such an arrangement permits the prompt adjustment of process conditions and/or the concentration of nucleating agents in the extrusion system in the event the foam cell size deviates from a preselected norm. The method comprises illuminating the surface of a foam sheet, receiving and collecting at least a portion of the light which is diffused and reflected from the foam sheet with a detector photocell, electrically measuring the amount of light energy received by the photocell and converting such measurements into a cell size measurement.