Methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls or sheets
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.
1. A pressure vessel having an internal pass-through multi-chambered cavity for gas impregnation of interleaved rolls, comprising:
at least two outer pressure chambers sandwiching a central pressure chamber, wherein the central pressure chamber is separated from each of the two outer pressure chambers by respective interior doors, and wherein each of the two outer and central pressure chambers are separably pressurable to selected first, second and third pressures, respectively; and
a rotatable shaft horizontally positioned within each of the two outer and central pressure chambers and through each of the interior doors of the multi-chambered cavity.
2. The pressure vessel of claim 1 wherein each of the interior doors include first and second door panels, wherein each first and second door panel is configured to sealingly engage together and about the longitudinally positioned rotatable shaft when each respective interior door is in a closed position, and wherein each first and second panel is configured to move laterally inward when each respective interior door is in an open position.
3. A pressure vessel having an internal pass-through multi-chambered cavity for gas impregnation of an intermittently fed thermoplastic material sheet, comprising:
at least two outer pressure chambers sandwiching a central pressure chamber, wherein the central pressure chamber is separated from each of the two outer pressure chambers by respective interior sealable pass-through slots, wherein each of the interior sealable pass-through slots is defined by a rectangular opening having a pair of adjacently positioned confronting static seals for sealably engaging the intermittently fed thermoplastic material sheet, and wherein each of the two outer and central pressure chambers are separably pressurable to selected first, second, and third pressures, respectively;
a sealable inlet at a first end portion of the pressure vessel, wherein the sealable inlet is defined by a rectangular inlet slot having a pair of adjacently positioned confronting static seals for sealably, engaging the intermittently fed thermoplastic material sheet;
a sealable outlet at a second end portion of the pressure vessel, wherein the sealable outlet is defined by a rectangular outlet slot having a pair of adjacently positioned confronting static seals for sealably engaging the intermittently fed thermoplastic material sheet; and
a roller system for intermittently conveying the thermoplastic material sheet through the sealable inlet, the outer and central pressure chambers by way of the interior sealable pass-through slots, and the sealable outlet.
4. The pressure vessel of claim 3 wherein the roller system resides partially within and partially outside the internal pass-through multi-chambered cavity.