摘要:
An apparatus and method for continuously reducing the viscosity of molten moldable polymeric material uses shear vibration under extensional flow to cause shear thinning and/or disentanglement. One or more station treatment cavities (3) are defined by a gap composed of two closely separated surfaces (6, 7) in relative motion with each other at given speed and/or submitted to relative oscillations, with given frequency and amplitude to produce a shear deformation on the molten material and a controlled variation of the gap dimension. The surfaces have a contour profile of ribs and/or bumps and/or grooves (5, 12) over which the molten moldable material can flow and/or can be dragged and/or is being pushed through and/or pumped through. The treatment cavities have an inlet (30) through which the molten moldable material can pass into, and an outlet (31) through which it can exit each treatment cavity.
摘要:
An apparatus and method include a mold which defines a mold cavity (200) with an inlet through which a molten, moldable material can pass into and/or through the mold cavity. A feeder for preparing the molten, moldable material, is spaced from the mold and expels the material to the mold cavity or to an accumulator connected to the mold cavity. A mechanism for controlling the temperature of the material in the feeder, accumulator, and the mold, as well as least one gas injection unit (1000, 2000) with controls for the gas before, during and after its injection into the mold cavity and/or into gas channels located within and/or around the mold cavity are provided. A closed loop regulating system easily adjusts and regulates the gas flow and monitors the average gas pressure of the injected gas according to a programmed conditioning signal. The gas injection unit has relief valves (10, 20) and gas tanks. Also included in the gas injection unit is gas purging/venting equipment equipment (2020) capable of producing a vacuum in the mold cavity and/or in the gas channels and/or inducing a differential or pressure creating flow of pressurized gas. Pressure, temperature and vibration probes (33, 51, 52, 53) are located in the mold assembly and in the gas injection unit(s) and are connected to transducers controlled by a computer. A controlled amount of volatile chemicals can be mixed with the inert gas of the gas injection unit. The apparatus includes one or more vibration devices (333, 444) to induce controlled high or low frequency low or high amplitude vibrations in the gas flowing. A mechanism controls the timing of activation of vibration during the filling, packing and cooling stages of the molding operation.
摘要:
First and second virgin polymers, not normally miscible when combined in one or more conventional melt-processing means, are combined in a known melt-processing means having mechanical vibration, referred to as a TekFlow® “processor” in which the polymers are extensively shear-thinned, substantially disentangled and stress-fatigues. A process in which melts of each virgin polymer are separately modified, mixed and melt-processed in a conventional extruder, is also effective if the melt of one polymer, modified in a processor, is mixed with virgin melt before being modified in another processor. In each embodiment, the resulting blend is unexpectedly found to be a single phase, that is, a miscible blend.
摘要:
An apparatus and method for continuously reducing the viscosity of molten moldable polymeric material uses shear vibration under extensional flow to cause shear thinning and/or disentanglement. One or more station treatment cavities (3) are defined by a gap composed of two closely separated surfaces (6, 7) in relative motion with each other at given speed and/or submitted to relative oscillations, with given frequency and amplitude to produce a shear deformation on the molten material and a controlled variation of the gap dimension. The surfaces have a contour profile of ribs and/or bumps and/or grooves (5, 12) over which the molten moldable material can flow and/or can be dragged and/or is being pushed through and/or pumped through. The treatment cavities have an inlet (30) through which the molten moldable material can pass into, and an outlet (31) through which it can exit each treatment cavity.
摘要:
A method for controlling the molecular weight and other properties of a polymer by permeating it with a small molecule while the polymer is in the solid state and optionally subjecting the polymer plus permeant blend to a melt processing operation. The polymer is optionally in a molecularly disentangled state.
摘要:
An apparatus and method include a mold which defines a mold cavity (200) with an inlet through which a molten, moldable material can pass into and/or through the mold cavity. A feeder for preparing the molten, moldable material, is spaced from the mold and expels the material to the mold cavity or to an accumulator connected to the mold cavity. A mechanism for controlling the temperature of the material in the feeder, accumulator, and the mold, as well as least one gas injection unit (1000, 2000) with controls for the gas before, during and after its injection into the mold cavity and/or into gas channels located within and/or around the mold cavity are provided. A closed loop regulating system easily adjusts and regulates the gas flow and monitors the average gas pressure of the injected gas according to a programmed conditioning signal. The gas injection unit has relief valves (10, 20) and gas tanks. Also included in the gas injection unit is gas purging/venting equipment equipment (2020) capable of producing a vacuum in the mold cavity and/or in the gas channels and/or inducing a differential or pressure creating flow of pressurized gas. Pressure, temperature and vibration probes (33, 51, 52, 53) are located in the mold assembly and in the gas injection unit(s) and are connected to transducers controlled by a computer. A controlled amount of volatile chemicals can be mixed with the inert gas of the gas injection unit. The apparatus includes one or more vibration devices (333, 444) to induce controlled high or low frequency low or high amplitude vibrations in the gas flowing. A mechanism controls the timing of activation of vibration during the filling, packing and cooling stages of the molding operation.
摘要:
Controlling viscosity of molten polymers, such as polycarbonate, prior to a molding operation such as injection molding, extrusion, thermoforming or blow molding, involves a reduction of viscosity in the plastic melt at constant temperature, by the action of a vigorous mechanical extensional shear vibration, with minimum or no external pressure, at a constant amplitude and frequency, causing the melt to become highly elastic and simultaneously fatigued for a certain time at that temperature, maintaining this high elastic state until the macromolecules have partially or totally disentangled, in a controllable manner, at which stage the melt is ready for a molding operation such as a simple quenching operation or an extrusion process followed by quenching to produce pellets or compounds with a better mix or a lower viscosity when remelted, or an injection molding operation where the melt viscosity has been greatly reduced allowing a better processability of the injected part.
摘要:
A continuous process for incorporating a thermally sensitive additive into a polymer melt of virgin polymer at a temperature at least 10°C below a temperature at which the virgin polymer is typically processed. The virgin polymer is first processed in an apparatus which extensively shear-thins the polymer until its normally entangled molecules are substantially disentangled. This is preferably done in a TekFlow® processor. The additive is then added to the resulting modified melt which is then processed in a high-shear apparatus, e.g. a co-rotating, twin-screw extruder, but more preferably in a second TekFlow® processor. This novel process allows making concentrates having a level of additive which could not be made to date and yet have the additive substantially uniformly dispersed. In particular a concentrate of polypropylene having a 30% by wt concentration of an organoclay in which the platelets are substantially uniformly dispersed, at least 10% more strongly intercalated than prior to treatment, and substantially fully exfoliated, is made with this process.
摘要:
Controlling viscosity of molten polymers, such as polycarbonate, prior to a molding operation such as injection molding, extrusion, thermoforming or blow molding, involves a reduction of viscosity in the plastic melt at constant temperature, by the action of a vigorous mechanical extensional shear vibration, with minimum or no external pressure, at a constant amplitude and frequency, causing the melt to become highly elastic and simultaneously fatigued for a certain time at that temperature, maintaining this high elastic state until the macromolecules have partially or totally disentangled, in a controllable manner, at which stage the melt is ready for a molding operation such as a simple quenching operation or an extrusion process followed by quenching to produce pellets or compounds with a better mix or a lower viscosity when remelted, or an injection molding operation where the melt viscosity has been greatly reduced allowing a better processability of the injected part.
摘要:
An apparatus and method include a mold which defines a mold cavity (200) with an inlet through which a molten, moldable material can pass into and/or through the mold cavity. A feeder for preparing the molten, moldable material, is spaced from the mold and expels the material to the mold cavity or to an accumulator connected to the mold cavity. A mechanism for controlling the temperature of the material in the feeder, accumulator, and the mold, as well as least one gas injection unit (1000, 2000) with controls for the gas before, during and after its injection into the mold cavity and/or into gas channels located within and/or around the mold cavity are provided. A closed loop regulating system easily adjusts and regulates the gas flow and monitors the average gas pressure of the injected gas according to a programmed conditioning signal. The gas injection unit has relief valves (10, 20) and gas tanks. Also included in the gas injection unit is gas purging/venting equipment equipment (2020) capable of producing a vacuum in the mold cavity and/or in the gas channels and/or inducing a differential or pressure creating flow of pressurized gas. Pressure, temperature and vibration probes (33, 51, 52, 53) are located in the mold assembly and in the gas injection unit(s) and are connected to transducers controlled by a computer. A controlled amount of volatile chemicals can be mixed with the inert gas of the gas injection unit. The apparatus includes one or more vibration devices (333, 444) to induce controlled high or low frequency low or high amplitude vibrations in the gas flowing. A mechanism controls the timing of activation of vibration during the filling, packing and cooling stages of the molding operation.