Abstract: Apparatus and methods are provided for controlling liquid levels in different vessels, and the blending of different materials in the separation and purification of polymeric materials in solution, such as polyethylene in cyclohexane.

Abstract: In the process for reducing the residual vinyl chloride monomer in an aqueous polyvinylchloride dispersion comprising the steps of depressurizing an aqueous polyvinylchloride dispersion containing emulsifiers and/or protective colloids as obtained from pressure polymerization in a polymerization zone, subjecting the same to a vacuum with heating, passing the gasses and foam of liquid constituents resulting from said depressurizing step and said vacuum treating step to a confined space wherein said gasses are separated from liquid constituents, and recovering an aqueous polyvinylchloride dispersion having a reduced residual vinyl chloride monomer content, the improvement consisting in passing said gasses and foam of liquid constituents to a confined space having a volume of not more than 331/3% of the volume of said polyvinylchloride dispersion and returning said foam of liquid constituents to said polyvinylchloride dispersion in said polymerization zone through an elongated zone of small cross-section below s

Abstract: A devolatilized room temperature vulcanizable silicone rubber composition comprising a silanol polymer, a plasticizing fluid, a cross-linking agent, a curing promoter and optionally, a filler wherein the plasticizing fluid and the silanol polymer are devolatilized prior to being mixed to form the room temperature vulcanizable silicone rubber composition by heating them at temperatures of at least 200.degree. C. under vacuum for at least 5 minutes. If there is utilized a filler and the filler is treated with cyclopolysiloxanes or silazanes, then preferably the filler is also devolatilized.

Abstract: Method for preparing a polymer alloy which is stable and homogeneous at high temperatures which comprises a component (a) one or more polymers of high molecular weight, having anhydride groups and component (b) one or more polymers of high molecular weight, having groups which have the ability to interact with hydrogen atoms to form hydrogen bonds. Initially, a solution of component (a) is prepared in an organic solvent and thereafter a solution of component (b) is added. Component (a), in the dissolved state, may be protolyzed in whole or in part, prior to or after the addition of component (b) by the action of protolyzing agents. After the solvent is removed formed products, such as granules, fibres, foils, foam, may be made from the polymer alloy.

Abstract: Polymers are continuously recovered from their latexes obtained by polymerization in emulsion by a process comprising the following steps:(A) feeding the polymeric latexes containing 10 to 50% by weight of polymer, at a temperature of from 10.degree. to 120.degree. C., through one or more feeding channels, to the narrow zone or to the divergent section of a nozzle in which water vapor flows at sonic or supersonic speed respectively, according to vapor/latex feeding ratios of 0.1-2 Kg of vapor/Kg of latex, where the latex is subdivided by the water vapor into a dispersion of particles; and(B) continuously feeding the dispersion obtained in step (A) to a tube or an exchanger of the type tube-in-tube directly connected with the divergent section of the nozzle where the dispersion, at a temperature of 100.degree.-150.degree. C. for residence times of from 0.1 to 1 second, maintains a speed of 50-150 m/sec.

Abstract: Method for preparing a polymer alloy which is stable and homogeneous up to high temperatures, from component (a) one or more polymers of high molecular weight, having anhydride groups and component (b) one or more polymers of high molecular weight, having groups which have the ability to interact with hydrogen atoms to form hydrogen bonds, wherein first a solution of component (a) is prepared in an organic solvent, to which solution then component (b) is added, whereas component (a) in dissolved state is protolyzed in whole or in part, prior to or after the addition of component (b) under the action of protolyzing agents, whereupon the solvent is removed; together with the formed products obtained from such a polymer alloy, such as granules, fibres, foils, foam, etc.

Abstract: The halogen and organic substances content of the catalyst residues in alpha-olefin crystalline (co)-polymers prepared with catalysts obtained by reacting:(a) a metallorganic Al compound with(b) a Ti compound supported on a Mg halide, in which an electron-donor is combined with the Ti compound and/or the Mg compound and optionally with (a),are reduced by passing a stream of superheated steam (optionally mixed with other gaseous fluids) over the polymer in powder form at a temperature of 105.degree.-140.degree. C. and under a pressure of 0.1-10 kg/cm.sup.2 gauge, the steam/polymer ratio being comprised between 0.10 and 1 by weight.

Abstract: Active polymerization catalyst is deactivated using a high molecular weight epoxide.

Abstract: Described herein is an improved process for preparing a polyarylate having a reduced viscosity of from about 0.5 to greater than 1.0 dl/gm which process comprises the following steps:(a) reacting an acid anhydride derived from an acid containing from 2 to 8 carbon atoms with at least one dihydric phenol to form the corresponding diester; and(b) reacting said diester with at least one aromatic dicarboxylic acid at a temperature sufficient to form the polyarylate, wherein the improvement comprises removing residual acid anhydride, after formation of the dihydric phenol diester, so that its concentration is less than about 1500 parts per million. The novel polyarylates produced by the improved process of this invention are melt stable and low in color.

Abstract: A process is disclosed for recovering polymer from a solution of the polymer in a solvent by high temperature phase separation in which a low molecular weight hydrocarbon is added to the solution, the solution and the added hydrocarbon are subjected to a temperature and pressure so that one liquid phase is formed and the pressure is reduced to form three phases, namely, a vapor phase rich in the hydrocarbon, a polymer-lean liquid phase and a polymer-rich liquid phase. The polymer-rich liquid phase is separated from the vapor phase and the polymer-lean liquid phase, and the polymer is then recovered from the polymer-rich liquid phase.

Abstract: Cationic polyelectrolytes in water-soluble powder form, applicable to the flocculation of municipal sludge comprise copolymers of acrylamide and of quaternized or salified dimethylamino-ethyl acrylate, containing in molar proportions 10 to 50% of cationic units distributed regularly along the copolymer chains. They have an intrinsic viscosity higher than 6 and a measured cationicity higher than 90% of the theoretical cationicity.

Abstract: Process for removing catalyst residues from atactic polypropylene is disclosed which comprises contacting the polypropylene with an aqueous solution of an alpha-hydroxysulfonic acid and then separating the polypropylene-containing phase from the aqueous phase.

Abstract: This invention relates to a distillation column for removing vinyl chloride monomer or other volatile material from an emulsion, suspension or dispersion containing such material. The apparatus comprises a column in which a series of inverted cones are mounted. The dispersion or emulsion is pulled downwardly over the cones and steam is fed into the column through sparges and flows upwardly against the descending stream of material. The low boiling materials are distilled out and recovered for reuse. The strips emulsion or dispersion are collected at the bottom of the column.

Abstract: There is provided a process and apparatus for the coagulation of an aqueous latex of a polymer wherein the latex and an aqueous coagulant are mixed in a tubular coagulation means which is disposed at an angle of from about 20.degree. up to 90.degree. to the horizontal plane and the coagulated mixture is passed from the tubular coagulation means to a conduit equipped with an impingement plate and then to means for separation, recovery and drying of the coagulated polymer.

Abstract: There is provided a process and apparatus for the coagulation of an aqueous latex of a polymer wherein the latex and an aqueous coagulant are mixed in a tubular coagulation means and the essentially completely coagulated mixture therefrom is passed into one or two vessels containing aqueous coagulant followed by separation, recovery and drying of the coagulated polymer.

Abstract: An improved process for the preparation of alkoxylated formaldehyde-amino compound resins. By using a sequential procedure, and an alkanol of up to 8 carbon atoms it is possible to remove both the water in the aqueous formaldehyde used and the water from the alkoxylation reaction azeotropically. The products of this invention afford resins of better quality, especially in terms of color and clarity, than the products derived from alcoholic formaldehyde solutions.

Abstract: The present invention relates to an improved falling strand devolatilizer apparatus having a plurality of stages for devolatilization providing polymers with lower residual monomer and/or volatile contents. The novel apparatus utilizes a final flash tank having two flash compartments that share a common heating and vacuum system wherein a recycle line transfers polymer melt from the first compartment to the second compartment for additional devolatilization.

Abstract: A device for separating a high pressure polyphase mixture consisting of a gas charged with liquid particles, and particularly a mixture of ethylene and polyethylene, which comprises a cylindrical vertical enclosure into which extends an inlet means for supplying the mixture thereto and which is provided at its lower end with an outlet for discharging separated liquids; a vertical cyclone in communication with the enclosure for receiving separated gases therefrom and having an outlet at its upper end for discharging gases separated in the cyclone and a liquid outlet at its lower end for discharging separated liquids therefrom; and an ejector comprising a nozzle, through which the polyphase mixture is fed, a mixing zone connected to the liquid outlet of the cyclone and a diffuser section for reducing the speed of the resultant mixture and being connected to the inlet means for supplying the polyphase mixture to the enclosure.

Abstract: A method of continuously treating an aqueous latex of a synthetic polymer which contains unreacted residual monomer from the polymerization reaction used for the production of the polymer, which method comprises feeding the aqueous latex as a spray into a vessel defining a chamber so that all or a substantial quantity of the droplets of spray avoid contact with the side wall of the chamber, and contacting the falling spray with steam flowing counter-current thereto whereby residual monomer is removed with the flow of steam leaving the chamber. Apparatus for carrying out the method is also claimed. The method is advantageously employed for the removal of residual vinyl chloride monomer from a latex of a vinyl chloride polymer.

Abstract: In preparing a solvent-polymer mixture for a subsequent reaction, e.g., metallation, wherein undesirable components lower boiling than the solvent, such as water, should be removed from the solvent and polymer, the undesirable components are removed by stripping using previously purified solvent, thereby preventing reboiler fouling. The stripping vapors are generated from solvent obtained from a source other than the fractionation column in which the stripping occurs in order to reduce costs. The process of this invention is particularly useful in removing water from a butadiene/styrene copolymer-cyclohexane solvent mixture prior to metallation of the copolymer.

Abstract: A solution polymerization process in which polymerizable diolefin monomer, is contacted under polymerization conditions in the presence of a volatile and inert earth hydrocarbon diluent having 3 to 5 carbon atoms per molecule and a hydrocarbon solvent having 6 to 10 carbon atoms per molecule to yield a product mixture easily concentrated by flash evaporation. In preferred embodiments the diluent is present in an amount such that the monomer concentration is about 30 to about 45 weight percent in the total of monomer and diluent entering the reaction and the solvent is present in an amount such that the weight ratio of the total of solvent and diluent to monomer entering the reaction is in the range of about 4:1 to 12:1.

Abstract: Butadiene is polymerized using hydrogen peroxide as a catalyst to provide polybutadiene (partaking of the nature of a polymethylenediol) suitable for use in making polyurethanes by reaction with diisocyanate compounds. Minor amounts of vinyl cyclohexene and related odiferous impurities are contaminants in such polybutadiene. Such contaminants are predominantly removed by selective volatilization during one or more treatments in a hot vacuum zone, the feedstock to the hot vacuum zone containing from about 0.4 to about 6% of a C.sub.9 --C.sub.13 saturated hydrocarbon entraining agent.

Abstract: Certain wet strength resins based on the epichlorohydrin/polyamine reaction which are characterized by extremely long gel times can be purified from epichlorohydrin residuals by azeotropic distillation.

Abstract: A process for the preparation of high molecular weight linear saturated polyesters derived from dicarboxylic acids or their ester-forming derivatives and aliphatic and/or cycloaliphatic diols, comprising the condensation of polyester precondensates having a relative viscosity of from 1.05 to 1.15 at from 220.degree. to 280.degree. C. under reduced pressure, wherein(a) the condensation is first started with from 70 to 95 percent by weight of the polyester precondensate and(b) after from 10 to 50% of the total condensation time the remaining 5 to 30 percent by weight of the polyester precondensate are added to the polyester melt undergoing condensation in accordance with (a), and the condensation is taken to completion.

Abstract: A process is provided for reducing the concentration of vinyl chloride monomer in a polymerized slurry obtained by the suspension-polymerization of vinyl chloride alone or a mixture of vinyl chloride with a monomer copolymerizable therewith, the improvement characterized in that a polymerized slurry at a temperature between 40.degree. C. and 100.degree. C. is jetted and/or flowed down into the gas phase portion of a vessel maintained at a pressure below atmospheric pressure.

Abstract: Process for the polymerization of vinyl chloride in aqueous suspension in the presence of dialkyl peroxydicarbonates in which the polymer is treated with a monobasic hydroxide at the end of polymerization and before the unreacted vinyl chloride is removed. The alkaline treatment is advantageously applied to polymers that are subsequently subjected to steam stripping.The treatment improves the initial heat stability of vinyl chloride polymers.

Abstract: An improvement in a process for removing residual vinyl chloride monomer from an aqueous dispersion of a synthetic polymer wherein the dispersion is subjected to boiling conditions while being maintained in a vessel having a vapor space above the liquid level of the dispersion. In the improved process, the content of vinyl chloride monomer in the dispersion is continuously monitored by a boiling point suppression technique.

Abstract: In a process for removing monomeric impurities from an aqueous dispersion of homopolymers or copolymers of vinyl chloride having a surface tension below 60 dyn/cm. by treatment with steam while avoiding foam formation by a rapid lowering of the pressure at high flow velocities, the improvement which comprises:(a) continuously mixing said dispersion in a flow pipe with steam at a steam pressure of 800-4660 millibars for an average residence time of about 0.01-5 seconds;(b) continuously passing the resultant admixture from said flow pipe at a velocity of at least 30 meters per second directly to a degasification vessel having a pressure of 133-660 millibars; and(c) continuously recovering a polymer product containing less than 20 p.p.m. residual monomer impurities therefrom.

Abstract: A process for reducing the glycol ether content in polyesters involves adding a glycol to a polyester oligomer solution prior to polymerization, distilling the oligomer solution to remove vapor containing the glycol as well as the glycol ether, and polymerizing the solution to produce a polyester containing a reduced glycol ether content.

Abstract: An aqueous dispersion of polyvinylchloride or vinylchloride copolymerizate is spray dried in a flow of drying air in a drying tower which contains at least one two-fluid nozzle for atomizing the aqueous dispersion and an injection member for pressurized air for providing the atomized particles with a rotary motion, about the longitudinal axis of the drying tower. A controlled rotary motion is imparted to the mixture of sprayed particles and the drying air. The heat economy and product quality are improved since it is possible to use a high drying air inlet temperature and to obtain an easily grindable powder suitable for producing stable, low viscosity plastisols.

Abstract: Vinyl chloride is removed from aqueous slurries prepared by the suspension polymerization of a monomer component that comprises vinyl chloride by heating the slurries at a temperature between 70.degree. C. and the boiling point of water at a pressure in the range of 30 mm Hg absolute to 3 atmospheres and removing the evolved vinyl chloride until the aqueous slurry contains less than 50 ppm and preferably less than 0.1 ppm of vinyl chloride, based on the weight of polymer in the slurry. The polymers that are recovered from the purified aqueous slurries contain less than 10 ppm, and in most cases less than 0.1 ppm of vinyl chloride.

Abstract: Vinyl chloride is removed from an aqueous dispersion that contains 5%-50% by weight of a vinyl chloride resin and 1000-15,000 ppm of vinyl chloride by a process in which the aqueous dispersion is contacted first with steam and vinyl acetate to remove at least 90% of the vinyl chloride from it and then, after a short conditioning period, with steam to reduce its monomer content to less than 10 ppm.

Abstract: Vinyl chloride is removed from polyvinyl chloride dispersions, latexes, and slurries by sparging them with an inorganic gas, such as air or ammonia, while they are maintained at subatmospheric pressure.

Abstract: Vinyl chloride is removed from polyvinyl chloride dispersions and latexes by adding to them from 2% to 8% by weight of a polar water-soluble organic compound that has a boiling point between about 50.degree. C. and 150.degree. C. and sparging the resulting mixtures with a gas, such as nitrogen, while they are maintained at subatmospheric pressure.

Abstract: A device for separating, collecting and returning particulate matter and/or mist entrained in gases is mounted across the vent opening. The mid-section of the device is made to communicate with the vent opening and is partially recessed therein resulting in minimum velocity of the gases escaping through either side of the device and reducing particulate build-up between working parts of the device and the vent opening.

Abstract: Dry particulate vinyl chloride homopolymer and copolymers, and dry particulate compositions containing major proportions of these polymers, having 2 parts or less per million of vinyl chloride monomer are provided. The vinyl chloride monomer can be so low as to be undetectable. The reduction in monomer content is achieved by subjecting the dry polymer particles to elevated temperature, agitation, and subatmospheric pressure.

Abstract: An improved method of degassing polymers and copolymers prepared by mass polymerizing a monomeric composition, based on vinyl chloride. The polymer is kept under agitation, the monomeric composition to be eliminated is brought from polymerization pressure to a pressure below 120 mm of mercury, the polymer is brought to or kept at a temperature of at least 70.degree. C. and below the temperature at which degradation of the polymer or copolymer commences, and these conditions of pressure and temperature are maintained substantially until the degassing process stops, the polymer being put into contact with a quantity of water representing 0.01 to 0.8% and preferably 0.05 to 0.5% of its weight, after the residual monomeric vinyl chloride content of the polymer or copolymer has been reduced below 2000 ppm. The polymers and copolymers obtained, before being placed in open air, have a residual monomeric vinyl chloride content which is less than 50 ppm, generally less than 20 ppm and may be as little as 1 ppm.

Abstract: A continuous process for the manufacture of ethylene copolymers under high pressure and at high temperature in a polymerization zone, with transfer of the reaction mixture into a high pressure product isolation zone and from there into a low pressure product isolation zone, and recycling of the unconverted gas from the high pressure product isolation zone into the polymerization zone and from the low pressure product isolation zone into a low temperature separator, from where the comonomer separated off is recycled to the polymerization process, while the ethylene is discharged as off-gas. The gas taken off the low pressure product isolation zone is preferably compressed to from 10 to 20 bar and cooled to from -10.degree. to -30.degree. C. before it is fed into the low temperature separator. There is a substantial improvement in the efficiency of separating off the comonomer.

Abstract: A sinuous shaped heat exchanger made up of a plurality of generally U-shaped heat exchanger units or sections or banks arranged with one of the ends of each of the U-shaped banks in opposing end to end relationship with one of the ends of a next succeeding bank in such a manner that places the outlet tube sheet of such bank supporting the outlet ends of the tubes of such bank face to face with the inlet tube sheet of the next bank supporting the inlet ends of the tubes of such next succeeding bank. The tubes at the outlet side of the outlet tube sheet and the tubes at the inlet side of the inlet tube sheet protrude toward each other beyond the surfaces of the tube sheets. A removable transition connecting piece in the form of an apertured plate with the same hole diameter and pitch as the tube sheets is sandwiched between the outlet tube sheet and the inlet tube sheet. It is removably secured in that position by securing it to the aforementioned ends of the banks.

Abstract: In a process for the recovery of an atactic polymer which comprises heating liquid propylene containing the dissolved atactic polymer at a gauge pressure of 13 to 40 kg/cm.sup.2 in a vaporizer to vaporize the propylene, and separating the atactic polymer from the vaporized propylene thereby recovering the polymer in a molten state, the improvement comprising maintaining the vaporization temperature of propylene at 45.degree. C. to 90.degree. C. and the temperature of a heating medium for the vaporizer at 60.degree. C. to 150.degree. C. According to this process, a long run can be used in the recovery of the atactic polymer.

Abstract: A process for the manufacture of vinyl chloride copolymers having a reduced content of free vinyl chloride comprising polymerizing a monomer mixture containing from 15% to 90% by weight of vinyl chloride under aqueous emulsion polymerization conditions with conventional post-polymerization, releasing the pressure, flushing the gas space above the copolymer dispersion free of monomer, cooling the copolymer dispersion to a temperature of from 10.degree. to 40.degree. C., adding a redox catalyst to the cooled dispersion consisting of from 0.002% to 0.5% by weight of the dispersion of an oil-soluble peroxy compound, and a water-soluble sulfur-containing reducing agent in a ratio of reducing agent to peroxy compound of 0.5 to 3 equivalents, allowing the dispersion to stand at a temperature of from 10.degree. to 40.degree. C. for a period of two hours to two days and recovering a copolymer dispersion having a vinyl chloride content of less than 50 ppm.

Abstract: This invention relates to a method for the removal of vinyl chloride monomer from polyvinyl chloride resins by lowering the Tg (glass transition temperature) of the polyvinyl chloride resins at an elevated temperature while in the presence of reduced pressure thus allowing the vinyl chloride monomer to escape from the polyvinyl chloride resins.

Abstract: A process for eliminating low molecular-weight polymers from the recirculating gases of facilities carrying out ethylene polymerization or copolymerization at a pressure of 300 to 2500 bars and a temperature of 130.degree. C. to 350.degree. C., in which facilities the mixture of monomer and polymer leaving the reactor is expanded into a separator operating under a pressure of 50 to 500 bars. The gases are passed, at a temperature at least 20.degree. C. higher than the melting point of the low molecular-weight polymers, through at least one standard cyclone at an inlet velocity between 1 and 10 m/s. The gases are then cooled to a temperature lower than the melting point of the low molecular-weight polymers, and are then passed through at least one heated cyclone at an inlet velocity between 2 and 20 m/s.

Abstract: By cooling the barrel of a devolatilizing extruder rather than by heating it, both the solvent removal rate and the polymer feed rate could be increased furthermore, the power surging of the motor driving the extruder was largely reduced or even eliminated by the process of this invention.

Abstract: A process is disclosed for producing powdery polycarbonate from a polycarbonate solution which comprises:(a) charging the solution into the feed opening of a disolvating apparatus, the apparatus being composed of a casing and having at least two screws incorporated therein, the screws meshing with each other; the apparatus comprising two parts; a evaporating zone and a powdering zone; a space being provided above the screws in the evaporating zone, the space extending in the axial direction of the screws and having at least one degassing opening, and side and bottom portions of screws generally fitting with the casing in the evaporating zone; top, side and bottom portions of screws generally fitting with the casing in the powdering zone, heating means being installed in the casing and/or screws;(b) in the evaporating zone, evaporating the solvent of the polycarbonate solution using the heating means while moving the solution by the screws;(c) powdering the dried polycarbonate in the powdering zone; and(d) dis

Abstract: A solution containing atactic polypropylene by-produced during the preparation of a propylene-containing polymer is passed through a tubular, elongated heating zone having a pressure difference of at least 3 kg/cm.sup.2 between its inlet and outlet so that the calculated flow velocity at the outlet is at least 40 m/sec, whereby sticky fine particles of molten atactic polypropylene substantially free of the solvent are formed in suspension in the vaporized solvent. Then, the sticky fine particles are separated from the vaporized solvent.

Abstract: A process for the production of thermoplastically processible moulding materials based on vinyl polymers of high chemical and molecular uniformity and having residual monomer contents of less than 0.1 mol % which comprises the steps of:(i) mass homogeneous phase polymerization of at least one vinyl monomer in a stirred continuously charged tank reactor to a conversion of from 25 to 60 mol %;(ii) directly concentrating the syrup consisting of residual monomers and vinyl polymer dissolved therein obtained from step (i) in a spiral tube evaporator at a temperature of from 60.degree. to 250.degree. C. and at a pressure of 100 m bar to 35 bar to obtain a solid content of vinyl polymer of from 40 to 90 mol %;(iii) directly charging the concentrate obtained from step (ii) to the inlet zone of a screw evaporator which consists of at least two sequential zones in order to effect further concentration, in which a first zone at a pressure of from 10 to 300 m bar and at a temperature of from 100.degree. to 250.degree. C.

Abstract: An improved method for separating branched polyphenylene from a polymerization reaction mixture is disclosed which improves polymer properties. The contents of a high pressure polymerization reactor are discharged into one or more devolatilizing units which draw off and recycle low molecular weight unreacted species and separate high molecular weight branched polyphenylene.

Abstract: A process for the continuous high pressure polymerization of ethylene in a polymerization system which comprises a polymerization zone (A), a high pressure product isolation zone (B), a throttling and control system (C), a low pressure product isolation zone (D), a second throttling and control system (E) and a discharge extruder (F), and wherein, according to the invention, the level of the ethylene polymer in the high pressure product isolation zone (B) and in the low pressure product isolation zone (D) is varied periodically. The process gives an ethylene polymer of improved homogeneity, which when used to manufacture films does not tend to form specks or fisheyes.

Abstract: A melt finish process is disclosed herein for working up solid, particulate polymer from a vapor state polymerization reactor, which reactor employs high yield catalysts, whereby the polymer is moved out of the reactor and into a post polymerization zone characterized by essentially adiabatic polymerization and the heat of such polymerization is used in raising the temperature of and melting said solid, particulate polymer to form molten polymer for further processing.