A method for infusing gas into a thermoplastic material includes positioning a sheet of a thermoplastic material into a vertical or substantially vertical position; positioning a sheet of a gas-permeable material into a vertical or substantially vertical position; and winding together the positioned sheet of thermoplastic material sheet and the positioned sheet of gas-permeable material to form a roll of the thermoplastic material interleaved with the gas-permeable material, the interleaved roll having a longitudinal axis oriented in a vertical or substantially vertical position. The method also includes exposing the interleaved roll to an atmosphere of a gas pressurized to infuse the thermoplastic material with the gas, while the longitudinal axis of the interleaved roll is oriented in a vertical or substantially vertical position; and then unwinding the gas-infused interleaved roll, while the longitudinal axis of the interleaved roll remains in a vertical or substantially vertical position.

Disclosed herein are roll fed air heated flotation ovens and related thermoforming systems, assemblies, and machines that enable the corrugation-free expansion of a gas impregnated thermoplastic web passing through an oven chamber (without use of a pin-chain assembly), as well as to related methods. In an embodiment, a gas impregnated thermoplastic web is conveyed and expanded through an elongated air heated oven chamber, wherein the elongated oven chamber includes a plurality of downwardly directed heated air nozzles positioned at regular intervals along and within the upper portion of the oven chamber, and a plurality of upwardly directed heated air nozzles positioned at regular intervals along and within the lower portion of the oven chamber, but staggered apart from the downwardly directed heated air nozzles such that the gas impregnated thermoplastic material web undulates in an up and down wavelike fashion, thereby minimizing sagging, bagging, puckering, and/or buckling of the web.

Disclosed herein are roll fed air heated flotation ovens and related thermoforming systems, assemblies, and machines that enable the corrugation-free expansion of a gas impregnated thermoplastic web passing through an oven chamber (without use of a pin-chain assembly), as well as to related methods. In an embodiment, a gas impregnated thermoplastic web is conveyed and expanded through an elongated air heated oven chamber, wherein the elongated oven chamber includes a plurality of downwardly directed heated air nozzles positioned at regular intervals along and within the upper portion of the oven chamber, and a plurality of upwardly directed heated air nozzles positioned at regular intervals along and within the lower portion of the oven chamber, but staggered apart from the downwardly directed heated air nozzles such that the gas impregnated thermoplastic material web undulates in an up and down wavelike fashion, thereby minimizing sagging, bagging, puckering, and/or buckling of the web.

Described herein are methods and processes of manufacturing irradiation crosslinked polypropylene foam. In some embodiments, this includes extrusion of all material components, including a liquid crosslinking agent, to manufacture extruded structures for production of irradiation crosslinked polypropylene foam.

Described herein are methods and processes of manufacturing irradiation crosslinked polypropylene foam. In some embodiments, this includes extrusion of all material components, including a liquid crosslinking agent, to manufacture extruded structures for production of irradiation crosslinked polypropylene foam.

A physically crosslinked, closed cell continuous foam structure derived from recycled metallized polyolefin material; polypropylene, polyethylene, or combinations thereof, a crosslinking agent, and a chemical blowing agent is obtained. The foam structure is obtained by extruding a structure comprising a foam composition, irradiating the extruded structure with ionizing radiation, and continuously foaming the irradiated structure.

A physically crosslinked, closed cell continuous foam structure derived from recycled metallized polyolefin material; polypropylene, polyethylene, or combinations thereof, a crosslinking agent, and a chemical blowing agent is obtained. The foam structure is obtained by extruding a structure comprising a foam composition, irradiating the extruded structure with ionizing radiation, and continuously foaming the irradiated structure.

A method for producing an extruded polystyrene foam in which when a foamable melted product, obtained by heat-melting a styrene resin composition and adding a foaming agent thereto in an extruder provided with a die slit section having an opening a (mm) in the thickness direction, is extrusion-foamed through the die slit section into a low pressure zone to form a plate-shaped foam, thereby obtaining an extruded polystyrene foam having a density of 20 kg/m.sup.3 or more and 45 kg/m.sup.3 or less, a closed cell ratio of 90% or more, and a thickness A (mm) of 10 mm or more and 150 mm or less, a foaming agent containing hydrofluoroolefin and other organic foaming agent is used, a thickness extension ratio A/a of an opening a in the thickness direction of the die slit section and a thickness A of the extruded polystyrene foam is adjusted to 18 or less, and a foamable melted product, just before the extrusion from the die slit section, is pressurized to 4.5 MPa or more and 10.0 MPa or less.

A method for producing an extruded polystyrene foam in which when a foamable melted product, obtained by heat-melting a styrene resin composition and adding a foaming agent thereto in an extruder provided with a die slit section having an opening a (mm) in the thickness direction, is extrusion-foamed through the die slit section into a low pressure zone to form a plate-shaped foam, thereby obtaining an extruded polystyrene foam having a density of 20 kg/m.sup.3 or more and 45 kg/m.sup.3 or less, a closed cell ratio of 90% or more, and a thickness A (mm) of 10 mm or more and 150 mm or less, a foaming agent containing hydrofluoroolefin and other organic foaming agent is used, a thickness extension ratio A/a of an opening a in the thickness direction of the die slit section and a thickness A of the extruded polystyrene foam is adjusted to 18 or less, and a foamable melted product, just before the extrusion from the die slit section, is pressurized to 4.5 MPa or more and 10.0 MPa or less.

An elongated structural article, having a continuous profile extrusion with spaced apart layers defining a portion of a cavity filed filled with thermoplastic pre-expanded beads expanded with steam in-situ causing the beads to securely bond together and to the profile extrusion. The article is cut to a length forming ends having an exposed foam core. A system for manufacturing the article is also disclosed having a profile extrusion die for forming an axially profile defining a wall surrounding a cavity, a tubular shaping mold located axially downstream of the extrusion die sized to support a length of the profile as it passes there through. A bead dispenser is oriented to introducing pre-expanded beads into the profile cavity while within the shaping fixture and a steam tube is oriented downstream of the introduction of pre-expanded beads. Control valves regulate the flow of pre-expanded beads and steam into the profile cavity.