Abstract:
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.
Abstract:
Disclosed herein are methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls and sheets. In one embodiment, the present invention is directed to a method for making a gas impregnated interleaved roll, which method comprises: providing a pressure vessel having an internal pressure chamber and a rotatable shaft horizontally positioned within the pressure chamber; placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet; pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts (thereby rotating the interleaved roll) while under pressure for a selected period of time; and depressurizing the internal chamber to yield the gas impregnated interleaved roll. In other embodiments, the invention is directed to multi-chambered pressure vessels for gas impregnation of thermoplastic rolls, sheets, and films.
Abstract:
The present invention relates to apparatuses and methods for making interleaved cylindrical rolls from a polymer roll and a porous roll. The interleaved rolls disclosed herein are useful for subsequent high pressure gas impregnation and solid-state foam processing. In one embodiment, an interleaving apparatus comprises: a first rotatable platform for unwinding a first cylindrical roll of a first sheet material, the first rotatable platform being rotatable about a first central axis; a second rotatable platform for unwinding a second cylindrical roll of a second sheet material, the second rotatable platform being rotatable about a second central axis; and a third rotatable platform for winding, while the first and second materials are unwinding, the first sheet material together with the second sheet material to yield the interleaved cylindrical roll, the third rotatable platform being rotatable about a third axis and proximate to the first and second rotatable platforms.
Abstract:
Disclosed herein are methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls and sheets. In one embodiment, the present invention is directed to a method for making a gas impregnated interleaved roll, which method comprises: providing a pressure vessel having an internal pressure chamber and a rotatable shaft horizontally positioned within the pressure chamber; placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet; pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts (thereby rotating the interleaved roll) while under pressure for a selected period of time; and depressurizing the internal chamber to yield the gas impregnated interleaved roll. In other embodiments, the invention is directed to multi-chambered pressure vessels for gas impregnation of thermoplastic rolls, sheets, and films.
Abstract:
Disclosed herein are methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls and sheets. In one embodiment, the present invention is directed to a method for making a gas impregnated interleaved roll, which method comprises: providing a pressure vessel having an internal pressure chamber and a rotatable shaft horizontally positioned within the pressure chamber; placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet; pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts (thereby rotating the interleaved roll) while under pressure for a selected period of time; and depressurizing the internal chamber to yield the gas impregnated interleaved roll. In other embodiments, the invention is directed to multi-chambered pressure vessels for gas impregnation of thermoplastic rolls, sheets, and films.
Abstract:
The invention disclosed herein relates to relates to foamed thermoplastic material objects and articles of manufacture having an internal layered cellular structure, as well as to methods of making the same. In one embodiment, the invention is directed to a multi-layer foamed polymeric article of manufacture, comprising: a non-laminated multi-layer thermoplastic material sheet, wherein the multi-layer thermoplastic material sheet has first and second discrete outer layers sandwiching a plurality of discrete inner foamed layers, and wherein the two outer layers and plurality discrete inner foamed layers are integral with one another. The thermoplastic material may be a semi-crystalline polymer such as, for example, PET (polyethylene terephthalate), PEEK (polyetheretherketone), PEN (polyethylene napthalate), PBT (polybutylene terephthalate), PMMA (polymethyl methacrylate), PLA (polylactide), polyhydroxy acid (PHA), thermoplastic urethane (TPU), or blends thereof. The two outer layers may be unfoamed skin layers having smooth outer surfaces, and the discrete inner foamed layers may be microcellular.
Abstract:
A solid state process utilizes gas impregnation to enhance thermoforming of thermoplastic material. If the gas is plasticizing, the article is thereby plasticized for thermoforming. In some embodiments, the invention provides foaming the polymer prior to or during thermoforming by creating high levels of dissolved gas during gas exposure. Foaming may proceed spontaneously upon decompression from gas pressure, or foaming may be enhanced by heating the polymer sheet near to or above the polymer's glass transition temperature, thereby producing plasticized foamed polymer for thermoforming. When objects of unfoamed polymer are desired, foaming may be suppressed by thermoforming gas saturated articles under gas pressure. This process may be used to enhance the thermoforming performance of articles that have been previously foamed, including articles foamed by prior art processes. In some embodiments, polymer is sufficiently plasticized so that it may be thermoformed without heating. Plasticization of the polymer is reversible.
Abstract:
The present invention is directed to a deep draw microcellularly foamed polymeric container comprising a polymeric sidewall integrally connected to a polymeric base along a bottom edge. The polymeric sidewall and base are contiguous with each other and define a shape of an open top container. The polymeric sidewall and base have a contiguous inner microcellular foam structure (having average cell diameters ranging from about 5 to about 100 microns) surrounded by a smooth outer skin layer integrally connected therewith. The polymeric sidewall defines a container height and a top opening, wherein the top opening defines a top opening width, and wherein the polymeric base defines a container base width, and wherein the area defined by the top opening is greater than the area defined by the polymeric base, and wherein the ratio of the container height (h) to the top opening width (w) is greater than about 1:1 (h:w).
Abstract:
The present invention is directed to a deep draw microcellularly foamed polymeric container comprising a polymeric sidewall integrally connected to a polymeric base along a bottom edge. The polymeric sidewall and base are contiguous with each other and define a shape of an open top container. The polymeric sidewall and base have a contiguous inner microcellular foam structure (having average cell diameters ranging from about 5 to about 100 microns) surrounded by a smooth outer skin layer integrally connected therewith. The polymeric sidewall defines a container height and a top opening, wherein the top opening defines a top opening width, and wherein the polymeric base defines a container base width, and wherein the area defined by the top opening is greater than the area defined by the polymeric base, and wherein the ratio of the container height (h) to the top opening width (w) is greater than about 1:1 (h:w).
Abstract:
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.