E.i. Dupont De Nemours and Company

Other

Daniel Gregory Tynan

Ioannis V Bletsos

James E Geary, Jr

Chi-Kai Shih

Ramdas Dujari

Rita S McMinn

Constantine D Papaspyrides

Francis Edward Jenkins

Thomas F Mistretta, Jr

Keith S Haight, Jr

A mixing apparatus suitable for mixing and conveying solid, particulate, polymeric materials, comprising a barrel that can be heated and cooled, at least two co-rotatable, self-wiping extruder screws located within the bore of the barrel, the screws being connected through a laterally flexible coupling to a drive means which can reverse the direction of rotation of the screws upon the occurrence of a predetermined event. The apparatus also comprises a closeable feed port and a closeable discharge port, both of which can be made gas-tight, the shafts of the screws being provided with seals capable of withstanding elevated gas pressures inside the barrel.

Polymer mixing apparatus and method

A staged feeding process for preparing a composition by mixing at least a first polymer and a second, dissimilar polymer forms a final composition comprising a uniform, small-particle dispersion of the first polymer in a matrix of the second polymer. Preferably, the first polymer has a melt viscosity greater than the second polymer. The process comprises the steps of feeding the first polymer in a first feed stage and feeding all of the second polymer as a melt at least two feed stages to mix the first and second polymers. Alternatively, the process may comprise feeding the first polymer in a first feed stage and feeding all of the second polymer in at least two feed stages subsequent to the first feed stage. In either case, this mixing initiates a chemical reaction between the first and second polymers.

Staged feeding process for mixing polymers

A mixing apparatus suitable for mixing and conveying solid, particulate, polymeric materials, comprising a barrel that can be heated and cooled, at least two co-rotatable, self-wiping extruder screws located within the bore of the barrel, the screws being connected through a laterally flexible coupling to a dirve means which can reverse the direction of rotation of the screws upon the occurrence of a predetermined event. The apparatus also comprises a closeable feed port and a closeable discharge port, both of which can be made gas-tight, the shafts of the screws being provided with seals capable of withstanding elevated gas pressures inside the barrel.

Polymer mixing apparatus

A linear polyamide having a weight average molecular weight above 200,000 is made by heating a lower molecular weight molten polyamide with thorough mixing at a temperature of about 265.degree.-300.degree. C. for at least 5 minutes while an inert gas is swept gently through the reactor, the increase of molecular weight of the polyamide being catalyzed by a particular phosphinic acid derivative.

Linear very high molecular weight polyamides and process for producing

Disclosed is a process for increasing the molecular weight of condensation polymers involving the use of a high velocity rarefied inert gas sweep in the polymer finishing process.

Process for production of condensation polymers

An apparatus for mixing or otherwise processing fluids, which apparatus comprises, within a housing, a rotating perforated drum positioned tangentially relative to an inner non-rotating stationary body that is located within the rotating perforated drum. The outer surface of the rotating perforated drum is also positioned tangentially relative to the inner surface of the housing or other outer non-rotating stationary body. In operation, zones are formed which promote mixing of the fluid being processed and generate new fluid surfaces, thereby facilitating mixing, degassing and/or reaction.

Apparatus and method for liquid mixing employing nip zones

An apparatus for processing materials, such as mixing or homogenizing fluids or dispersing a fluid in a viscous material, comprises a housing having bores and at least one inlet port and an outlet port disposed in the housing and in fluid communication with the bores. A pressure mechanism is disposed outside the housing and is in communication with the inlet port for introducing the materials under pressure to the bore and for forcing the materials through the bores to the outlet port. A rotor is disposed in each bore. The rotors do not contact each other. Each rotor has teeth, and the teeth of one rotor mesh with the teeth of an adjacent rotor so that the materials are squeezed in the space between two adjacent teeth of one rotor and the meshing tooth of the other rotor to impart stretching flow to the materials and to expel the materials from the interstices between the teeth of the one rotor and the other rotor.

Apparatus for processing materials

An apparatus for treating a medium in situ includes counter-rotating shafts and intermeshed blades arranged on the shafts in a helical array to define mixing zones along the length of the shafts. Reagent supply conduits are disposed in a housing surrounding the upper ends of the shafts for introducing reagents into the mixing zones. The housing is attached to a mobile excavator which moves the shafts horizontally and vertically. The shafts are lowered into the medium by the excavator and are counter-rotated to cause the blades to pump the medium and the reagents along the shafts. Once at the desired operating depth, the shafts are moved below the surface of the medium in the horizontal direction generally perpendicular to the plane of the axes of the shafts to define a volume in the medium. The medium and the reagent are mixed vertically and laterally in the mixing zones and are further mixed horizontally as the mixing zones traverse the medium in the horizontal direction, thereby mixing the reagent and the medium in the volume in both the vertical and the horizontal direction to stabilize and homogenize the medium. The shafts are then withdrawn from the medium and the process is repeated for a second volume disposed adjacent the first volume. The apparatus and the method associated with operating the apparatus result in very uniform stabilization and homogenization of a medium at a rapid rate and a low cost.

Apparatus and method for in-situ treatment of a medium

Counter-rotating intermeshing rotors are employed to generate films of viscous material to enhance processing. The rotors are configured that they trap viscous material in open-ended chambers defined by the rotor surfaces. As rotation proceeds the chambers decrease in volume and the material is expelled through the ends of the chambers as a film. Longitudinally adjacent rotors each have a different angular orientation about their centers of rotation to provide a sawtooth stepped helix to convey material longitudinally.

Apparatus for forming films of constant thickness

This invention relates to a screw processor having multiple fully intermeshed co-rotating in-phase screws each provided with equal numbers of threads, each of said screws having longitudinally staged eccentric cross-sections preselected so that at least one thread of each screw spreads process material over the barrel bore and at least one other thread of each screw collects said process material and transfers it to a co-acting screw, which thereupon repeats the spreading-collecting-transfer cycle.

Co-rotating multiple screw processor

A continuous process for preparing particulate microporous, open-celled polymer structures in a co-rotating twin-screw processor comprising agitating normally solid organic polymer and chlorofluorocarbon in the melt zone of said processor, cooling the resulting solution under agitation in the cooling and milling zone, extruding a snow-like mass from the cooling and milling zone, and then removing the chlorofluorocarbon from the snow-like mass to leave the polymer structures.

Continuous process for preparing particulate microporous, open-celled

Clear, bubble-free acrylonitrile polymer solutions of high polymer concentration are rapidly prepared by feeding powdered acrylonitrile polymer to a cool zone of a twin-screw machine and injecting solvent to form a slurry at a temperature below 40.degree. C., advancing the cool slurry to a heated zone and converting the slurry into a concentrated solution at 110.degree. to 150.degree. C. while intermittently squeezing it in directions transverse to the axes of the screws, and discharging the hot solution continuously from the machine. A zone of reduced pressure is provided to remove gases trapped in the slurry. A twin-screw machine for carrying out the process is disclosed.

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Wilmington, DE, United States of America

Daniel Gregory Tynan