Abstract: A process for component separation in a polymer production system, comprising separating a polymerization product stream into a gas stream and a polymer stream, wherein the gas stream comprises ethane and unreacted ethylene, distilling the gas stream into a light hydrocarbon stream, wherein the light hydrocarbon stream comprises ethane and unreacted ethylene, contacting the light hydrocarbon stream with an absorption solvent system, wherein at least a portion of the unreacted ethylene from the light hydrocarbon stream is absorbed by the absorption solvent system, and recovering a waste gas stream from the absorption solvent system, wherein the waste gas stream comprises ethane, hydrogen, or combinations thereof.

Abstract: An olefin polymerization reactor comprising a tubular portion that extends in a vertical direction; a tapered portion disposed inside the tubular portion, an inside diameter of the tapered portion decreasing downwardly, and including a vertically penetrating orifice at a bottom end thereof; a tubular lower deflector disposed above the orifice of the tapered portion, an outside diameter of the tubular lower deflector increasing downwardly, a bottom end thereof being located away from an inner wall of the tubular portion, and including a vertically penetrating orifice at a top end thereof; and an upper deflector disposed above the orifice of the lower deflector, an outside diameter of the upper deflector increasing downwardly, a top end thereof being closed, a bottom end thereof being located away from the inner wall of the tubular portion, and an outside diameter at the bottom end being equal to or greater than an inside diameter of the orifice of the lower deflector.

Abstract: A system and method for polymerizing olefin in the presence of a chain transfer agent in a first reactor to form a first polyolefin, discharging from the first reactor a transfer slurry having the first polyolefin and the chain transfer agent, and processing the transfer slurry in a separator to remove chain transfer agent and to provide a fluff slurry having the first polyolefin and a lower content of chain transfer agent than in the transfer slurry. The system and method provide for feeding the fluff slurry to a second reactor, polymerizing olefin in the second reactor to form a second polyolefin, and discharging from the second reactor a slurry having the second polyolefin.

Abstract: A finely divided, cationic or amphoteric, aqueous polymer dispersion which is obtainable by emulsion polymerization of ethylenically unsaturated monomers in the presence of a cationic or amphoteric protective colloid, wherein first the cationic or amphoteric protective colloid is prepared by polymerizing a monomer blend in the presence of at least one first polymerization initiator in an organic solvent, and is carried out in a pressurized reactor at a pressure of at least 1720 kPa and at a temperature of at least 150° C.

Abstract: Process for producing polyamides that are stable during processing, by treating the polyamide during the solid-phase postcondensation process with a gas which comprises carrier gas (inert gas), water, and acid, or an anhydride or lactone or a mixture of these or, respectively, comprises ammonia, or amine, or a mixture of these, at a temperature from 130 to 200° C. and at a pressure of from 0.01 to 10 bar.

Abstract: The present invention relates to a polypropylene composition comprising comonomer units derived from ethylene in an amount of from 1.5 wt % to 35 wt %, and from at least one C5-12 alpha-olefin in an amount of from 1.0 mol % to 3.0 mol %, wherein the polypropylene composition has an amount of xylene solubles XS of at least 40 wt %, and the xylene solubles have an amount of ethylene-derived comonomer units of from 4.0 wt % to 70 wt %.

Abstract: The invention is to provide polycarbonate resins having excellent light resistance, transparency, hue, heat resistance, thermal stability, and mechanical strength and to provide processes for efficiently and stably producing a polycarbonate resin which stably shows those performances. The invention includes: polycarbonate resins which at least contain structural units derived from a dihydroxy compound having the portion represented by formula (1) as part of the structure thereof and which have specific properties; and processes for producing the polycarbonate resins, CH2—O??(1) where the case where the portion represented by formula (1) is part of —CH2—O—H is excluded.

Abstract: A heat exchange module for use in a chemical, pharmaceutical or biological reactor system can include a body configured to be disposed in the reactor system having an inner replaceable reactant container is disclosed. The body can further include at least one thermally conductive surface adapted to contact the inner replaceable reactant container to facilitate heat transfer. Furthermore, the heat exchange module can include a heat exchanger disposed within the module body and can include a fluid circulation path through which a heat exchange fluid can be circulated.

Abstract: Polymerization process including polymerizing a monomer and a comonomer in a polymerization reaction, withdrawing an effluent stream containing solid polymer and a mixture of unreacted monomer and unreacted comonomer, and passing the effluent to a high pressure recovery system having (a) a high pressure separation step for separating vapor containing unreacted monomer and unreacted comonomer from the solids, and (b) a high pressure recycle system for recycling a portion of the vapor to the polymerization reaction, passing the solids from the high pressure recovery system to a low pressure recovery system having (a) a low pressure separation step for separating further unreacted monomer and unreacted comonomer from the solids, and (b) a low pressure recycle system for recycling at least a portion of the unreacted monomer and unreacted comonomer to the polymerization reaction. A portion of the vapor separated in step 2(a) is passed to the low pressure recovery system.

Abstract: A system and method for a polyolefin reactor temperature control system having a first reactor temperature control path, a second reactor temperature control path, and a shared temperature control path. The shared temperature control path is configured to combine and process coolant return streams, and to provide coolant supply for the first reactor temperature control path and the second reactor temperature control path.

Abstract: This invention relates to processes using staged hydrogen addition in propylene polymerization. Using this process, broad/bi-modal MWD iPP with excellent stiffness properties and melt flow rates were produced.

Abstract: The present invention provides a novel continuous polymerization apparatus which is able to efficiently produce a polymer composition suitable for obtaining a resin composition with high quality. In a continuous polymerization apparatus, at least, a first reactor of a complete mixing type and a second reactor of a complete mixing type (10, 20) are used. Each of the reactors (10, 20) is provided with a supply port (11a, 21a), an effluent port (11b, 21b), and a temperature detecting means (T) for detecting a temperature in the reactor, wherein the supply port (11a) of the first reactor (10) is connected to the supply sources (1, 3) of a raw material monomer and a polymerization initiator, and the effluent port (11b) of the first reactor is connected through a connection line (15) provided with a cooling means (16) to the supply port (21a) of the second reactor (20).

Abstract: The present invention is directed to processes for making a crosslinked cation exchange polymer comprising a fluoro group and an acid group. The process allows the polymer to be efficiently made on a commercial scale, and the polymers are useful to bind potassium in the gastrointestinal tract of a human or animal subject.

Abstract: A process for preparing a homogeneous polyethylene product can include producing a first polyethylene resin in the presence of a metallocene catalyst in a reactor. The first polyethylene resin can have a density of from 0.940 to 0.970 g/cm3. The first polyethylene resin can have a Low Molecular Weight (LMW) with an MI2 of between 2 and 250 g/10 min. The process can include separately producing a second polyethylene resin in the presence of a Ziegler-Natta catalyst in a reactor. The second polyethylene resin can have a High Molecular Weight (HMW) with an MI2 of between 0.01 and 15 g/10 min. The process can include physically blending together the first polyethylene resin and the second polyethylene resin to produce the homogeneous polyethylene product.

Abstract: The invention relates to a reactor assembly for the production of polymers including a fluidized bed reactor (1) comprising a bottom zone (5), a middle zone (6) and an upper zone (7), an inlet (8) for the fluidization gas located in the bottom zone (5), an outlet (9) for the fluidization gas located in the upper zone (7); the outlet (9) for the fluidization gas being coupled with the fluidized bed reactor (1) via inlet (8); the equivalent cross-sectional diameter of the bottom zone (5) being monotonically increasing with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the middle zone (6) having an essentially constant equivalent cross-sectional diameter with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the equivalent cross-sectional diameter of the upper zone (7) being monotonically decreasing with respect to the flow direction of the fluidization gas through the fluidized bed reactor; wherein that the ratio of the height of

Abstract: Reactor assembly for the production of polymers including a fluidized bed reactor (1) comprising a bottom zone (5), a middle zone (6) and an upper zone (7), an inlet (8) for the fluidization gas located in the bottom zone (5), an outlet (9) for the fluidization gas located in the upper zone (7); the outlet (9) for the fluidization gas being coupled with the fluidized bed reactor (1) via inlet (8) via a gas circulation line; means for separation of solids from gas (2) being connected to said gas circulation line; the equivalent cross-sectional diameter of the upper zone (7) being monotonically decreasing with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the middle zone (6) having an essentially constant equivalent cross-sectional diameter with respect to the flow direction of the fluidization gas through the fluidized bed reactor; the equivalent cross-sectional diameter of the bottom zone (5) being monotonically increasing with respect to the flow direction of the fl

Abstract: An ethylenic polymer comprising amyl groups from about 0.1 to about 2.0 units per 1000 carbon atoms as determined by Nuclear Magnetic Resonance and both a peak melting temperature, Tm, in ° C., and a heat of fusion, Hf, in J/g, as determined by DSC Crystallinity, where the numerical values of Tm and Hf correspond to the relationship Tm?(0.2143*Hf)+79.643. An ethylenic polymer comprising at least one preparative TREF fraction that elutes at 95° C. or greater using a Preparative Temperature Rising Elution Fractionation method, where at least one preparative TREF fraction that elutes at 95° C. or greater has a gpcBR value greater than 0.05 and less than 5 as determined by gpcBR Branching Index by 3D-GPC, and where at least 5% of the ethylenic polymer elutes at a temperature of 95° C. or greater based upon the total weight of the ethylenic polymer.

Abstract: Provided are processes for making polymer compositions, especially those with reduced or no gel formation in lubricating oils as identified by rheological and visual gel tests and which are useful as viscosity modifiers. The processes described herein aim to achieve this objective by adjusting the concentrations of the hydrogen feed(s) in the first and/or second polymerization reaction zones, preferably such that (a) the hydrogen feed concentration in the first polymerization reaction zone is 0.0-1.0 wt %, based on total weight of feed(s) of hydrogen, ethylene monomer, ?-olefin comonomer, and solvent into the first polymerization reaction zone, and/or (b) the hydrogen feed concentration in the second polymerization reaction zone is 0.0-0.5 wt %, based on total weight of feed(s) of hydrogen, ethylene monomer, ?-olefin comonomer, and solvent into the second polymerization reaction zone.

Abstract: Process for transferring polyolefin particles from a first gas-phase polymerization reactor to a second gas-phase polymerization reactor in a multistage polymerization of olefins carried out in at least two serially connected gas-phase polymerization reactors, wherein the first gas-phase reactor is a fluidized-bed reactor comprising a gas distribution grid and a settling pipe, which is integrated with its upper opening into the distribution grid and contains a bed of polyolefin particles which moves from top to bottom of the settling pipe, the process comprising the steps of introducing a fluid into the settling pipe in an amount that an upward stream of the fluid is induced in the bed of polyolefin particles above the fluid introduction point; withdrawing polyolefin particles from the lower end of the settling pipe; and transferring the withdrawn polyolefin particles into the second gas-phase polymerization reactor, process for polymerizing olefins comprising such a process for transferring polyolefin p

Abstract: The invention relates to a method for producing a polymer using a chain transfer agents. In particular, the invention relates to a process for polymerizing a polymer in the presence of a mixture of at least two chain transfer agents, which mixture comprises a polar chain transfer agent (polar CTA), and a non-polar (non-polar CTA).

Abstract: The invention refers to a process for preparing a Group 2 metal/transition metal olefin polymerization catalyst component in particulate form for polymerizing olefins, especially ethylene or propylene or comonomers thereof.

Abstract: The present invention relates to polymer compositions comprising a propylene impact copolymer and a processing aid, as well as corrugated boards made from such compositions. The impact copolymer has a melt flow range of from 1.5 to 3.5 g/10 min and a dispersed phase content of from 5 to 30% by weight. The dispersed phase of the impact copolymer has an ethylene content of from 30- to 70% by weight of the dispersed phase. The matrix phase of the impact copolymer is a propylene homopolymer or a random copolymer comprising units derived from propylene and a second copolymer selected from either ethylene or 1-butene wherein the units derived from the second copolymer comprise from 0 to 5% by weight of the dispersed phase.

Abstract: A method of preparing a catalyst comprising contacting an acidic colloidal silica suspension with a titanium-containing compound to form a mixture, adjusting the pH of mixture to about neutral to form a catalyst support, and contacting the catalyst support with chromium-containing compound to from a chromium-supported catalyst. A catalyst support prepared by contacting a colloidal silica suspension and a titanium-containing compound under acidic conditions to form a mixture, and contacting the mixture with a basic material in an amount sufficient to increase the pH of the mixture to about 7.

Abstract: The disclosure includes a polymerization process and an olefin polymerization system. A polymerization product is produced, a vapor phase is recovered from the polymerization product, the vapor phase is fractionated in a first column to yield a fraction stream, and the fraction stream is fractionated in a second column. A first stream of the second column, which comprises a diluent, can be recycled to a first polymerization reactor. A second stream of the second column, which comprises olefin monomer, diluent, and hydrogen, can be recycled to a second polymerization reactor. Comonomer may be recycled from the first column to the first polymerization reactor, the second polymerization reactor, or both.

Abstract: The present invention relates to polymer compositions comprising a propylene impact copolymer and a processing aid, as well as corrugated boards made from such compositions. The impact copolymer has a melt flow range of from 1.5 to 3.5 g/10 min and a dispersed phase content of from 5 to 30% by weight. The dispersed phase of the impact copolymer has an ethylene content of from 30- to 70% by weight of the dispersed phase. The matrix phase of the impact copolymer is a propylene homopolymer or a random copolymer comprising units derived from propylene and a second copolymer selected from either ethylene or 1-butene wherein the units derived from the second copolymer comprise from 0 to 5% by weight of the dispersed phase.

Abstract: A gas-phase polymerization reactor having interconnected polymerization zones comprising:—a riser through which the polymer particles flow upwards under fast fluidization conditions or transport conditions;—a downcomer through which the polymer particles flow downward in a densified form under the action of gravity, the bottom of said downcomer being connected to the lower region of said riser by means of a transport section, said transport section being designed as a bend descending from the downcomer to the riser.

Abstract: The present invention relates to a reactor (10) and a process for continuous polymerization, where the reactor (10) has an essentially tubular reactor housing (16). The reactor housing (16) has a drive (38) which runs along the geometric central axis (12) in the flow direction (22) and is configured as a central shaft. A rotatably arranged scraper or wiper (36) is provided within the reactor housing (16); the scraper or wiper (36) has at least one scraper or wiper blade (42) to run along an interior side (44) of the reactor housing (16). The rotational movement of the scraper or wiper (36) results in radial mixing of a stream within the reactor housing (16) which dominates gravity effects and, by virtue of shaping of the scrapers or wipers, optionally makes plug flow or a loop flow or backflow within the reactor (10) or else via an additional external pumped circulation system (23) possible.

Abstract: Polymer blends suitable for packaging are disclosed that include one or more impact modifiers; and one or more polyethylene terephthalate homopolymers or copolymers obtained by a melt phase polymerization using a catalyst system comprising aluminum atoms in an amount, for example, from about 3 ppm to about 60 ppm and one or more alkaline earth metal atoms, alkali metal atoms, or alkali compound residues in an amount, for example, from about 1 ppm to about 25 ppm, in each case based on the weight of the one or more polyethylene terephthalate homopolymers or copolymers The polymer blends disclosed exhibit improved low temperature toughness compared with blends made using polymers prepared with conventional catalyst systems.

Abstract: The process for producing aromatic polyether sulfones via reaction of a dichlorodiphenyl sulfone component with a bisphenol component as monomers in the presence of alkali metal carbonate in the melt in the absence of solvents and diluents comprises carrying out the reaction in a mixing kneader which is operated with a shear rate in the range from 5 to 500 s?1.

Abstract: The present invention relates to a production method for efficiently obtaining an acrylic acid-based polymer having a narrow molecular mass distribution and a low molecular mass, without using a large amount of chain transfer agent. A method for continuously producing an acrylic acid-based polymer obtained by continuously polymerizing a monomer having acrylic acid as an essential component, characterized in that a liquid feed pump applies a mechanical load of 0.5 to 2.5 kJ/L to the liquid discharged from the outlet of a reactor. An acrylic acid-based polymer having fewer high-molecular-mass components, excellent dispersion and other properties, and a low molecular mass is thereby obtained.

Abstract: The present disclosure provides a system for recovering emissions generated from an olefin polymerization process, comprising: a devolatilizer for receiving a fresh sweep gas and emissions generated from the olefin polymerization process and outputting a first fluid and a polyolefin resin; a compression refrigeration unit including a compression device and a first heat exchange device, for receiving said first fluid and outputting a first gas-liquid mixture; a first gas-liquid separation device for separating the first gas-liquid mixture and outputting a first recovery product and a first gas phase composition; a first gas separation device for receiving the first gas phase composition, removing small molecular substances therefrom, and outputting a composition rich in small molecular gases and a second gas phase composition rich in hydrocarbons; and a second gas separation device having a second heat exchange device, a second gas-liquid separation device, and a first gas expansion device.

Abstract: Embodiments of the present disclosure relate to a method of preparing polyethylene compositions comprising polymerizing ethylene in a first gas-phase reactor and polymerizing ethylene in a second gas-phase reactor in the presence of hydrogen; wherein at least one of the first or second gas-phase reactors comprises a first and second polymerization zone; wherein a hydrogen pressure of the first and second polymerization zones are different such that at least a portion of the second ethylene cycles through the first and second polymerization zones and a gas mixture of each polymerization zone is partially or totally prevented from entering the other zone.

Abstract: This invention relates to processes using staged hydrogen addition in propylene polymerization. Using this process, broad/bi-modal MWD iPP with excellent stiffness properties and melt flow rates were produced.

Abstract: The invention provides a fluidized bed polymerization reactor, including: a column, in which a liquid distributor and a gas distributor above the liquid distributor are arranged, so that the reaction zone being divided into a first zone and a second zone through the gas distributor; and a circulating unit for circulating the gas material originated from the top zone of the column into the bottom zone thereof in a form of gas-liquid mixture. The gas-liquid mixture is undergone a gas-liquid separation in the bottom zone, the gas phase portion obtained being fed to the gas distributor and then into the second zone while the liquid phase portion obtained being entered into the first zone through the liquid distributor, so that the temperature in the first zone is lower than that in the second zone. Therefore, polymer with a molecular weight distributed in a relatively wide range can be obtained. The invention further provides a method for preparing polymer.

Abstract: A low-gloss thermoplastic resin composition that can have excellent heat resistance and weather resistance of the present invention includes (A) a thermoplastic resin forming a first dispersed phase; and (B) an acrylic resin forming a second dispersed phase, wherein the first dispersed phase has a network configuration.

Abstract: In a process for making a copolymer, a first product stream comprising a semi-crystalline polymer and a chain terminating agent is produced in a first reactor system. The first product is provided to a second reactor system wherein a low crystallinity polymer is produced in the presence of the semi-crystalline polymer. At least a portion of the chain terminating agent is removed from the second reactor system by an in-situ process.

Abstract: A process for polymerizing ethylene to produce an ethylene-based polymer including contacting ethylene with a Ziegler-Natta procatalyst, an alkylaluminum cocatalyst and a self limiting agent selected from the group of aliphatic, cycloaliphatic, substituted cycloaliphatic or aromatic esters, anhydrides and amides such that the self limiting agent reduces polymerization rates to no greater than 40% of the polymerization rate in the absence of the self limiting agent at temperatures equal to or greater than 120° C. is provided.

Abstract: A polymerization process comprising (A) polymerizing ethylene in the presence of a catalyst to form a semi-crystalline ethylene-based polymer in at least one reactor; the catalyst comprising an organometallic catalyst thereby forming an ethylene-based polymer composition in the at least one reactor, wherein the catalyst is a metal complex of a polyvalent aryloxyether corresponding to the formula: wherein step (A) is conducted in the presence of from 5 to 20 mmol/m3 triethylaluminum; and wherein step (A) is conducted in the presence of one or both of the following conditions: (i) from greater than 0:1 to 65:1 molar ratio of triethylaluminum to the catalyst; and (ii) from 0.1:0 to 5:1 molar ratio of triethylaluminum to modified methylalumoxane is provided.

Abstract: A system and method for polymerizing olefin in the presence of a chain transfer agent in a first reactor to form a first polyolefin, discharging from the first reactor a transfer slurry having the first polyolefin and the chain transfer agent, and processing the transfer slurry in a separator to remove chain transfer agent and to provide a fluff slurry having the first polyolefin and a lower content of chain transfer agent than in the transfer slurry. The system and method provide for feeding the fluff slurry to a second reactor, polymerizing olefin in the second reactor to form a second polyolefin, and discharging from the second reactor a slurry having the second polyolefin.

Abstract: There is provided a method capable of producing a methacrylic-based polymer excellent in pyrolysis resistance and excellent in fabricability in a high productivity. The method for producing a methacrylic-based polymer includes the following steps (1) and (2): step (1) of using a complete mixing reactor (A) to thereby obtain the first syrup, including specific steps; step (2) of using a reaction apparatus (D) including a plug flow mixer (B) and a plug flow reactor (C) to thereby obtain the second syrup, including specific steps.

Abstract: This invention discloses caps and closures produced by injection molding with a bimodal high density polyethylene (HDPE) resin comprising a low molecular weight, high density polyethylene fraction substantially free of comonomer and a high molecular weight, low density polyethylene fraction, having a molecular weight distribution of at least 3.5, preferably greater than 4.0, prepared in two reactors connected in series in the presence of a metallocene-containing catalyst system, wherein the metallocene comprises a bisindenyl or a bis-tetrahydrogenated-indenyl component.

Abstract: A polypropylene composition for injection-molded drainage systems comprising 78-84 wt % of a crystalline propylene polymer, 8 to less than 13 wt % of an elastomeric copolymer and 8 to less than 13 wt % of polyethylene. The said composition exhibits a flexural modulus value higher than 1400 MPa, a melt flow rate (MFR), determined according to ISO method 1133 (230° C. and 2.16 kg), of from 1.5 to 5.0 g/10 min, and a value of Izod impact resistance at 0° C. of more than 6 kJ/m2 according to ISO method 180/1A.

Abstract: A dual reactor solution process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer and which have good processability, toughness, and environmental stress crack resistance combined with good organoleptic properties. The polyethylene compositions are suitable for compression molding or injection molding applications and are particularly useful in the manufacture of caps and closures for bottles.

Abstract: Continuous polymerization apparatus including a first reactor of a complete mixing type and a second reactor of a complete mixing type (10, 20). Each of the reactors (10, 20) is provided with a supply port (11a, 21a), an effluent port (11b, 21b), and a temperature detecting means (T) for detecting a temperature in the reactor, wherein the supply port (11a) of the first reactor (10) is connected to the supply sources (1, 3) of a raw material monomer and a polymerization initiator, and the effluent port (11b) of the first reactor is connected through a connection line (15) to the supply port (21a) of the second reactor (20). Connection line (15) is combined with a secondary line (15?) for supplying a raw material monomer at a combining part (M) located between the effluent port (11b) of the first reactor (10) and the supply port (21a) of the second reactor (20).

Abstract: A method for producing a propylene-based polymer, including polymerizing propylene or propylene and an ?-olefin except propylene in the presence of a catalyst with a horizontal polymerization reactor equipped with stirring vanes rotating around a horizontal axis therein by a continuous vapor-phase polymerization, which removes heat of polymerization by heat of vaporization of a liquefied propylene, wherein the reactor can set a plurality of area sections different in temperature in a horizontal direction inside the reactor, and satisfies at least one of i) a temperature difference, ?T1=T??T?, between an area section including an upstream end of the reactor (T?) and a downstream end (T?) thereof is 0.1 to 20° C. and ii) a temperature difference, ?T2=Tx?Tz, between an area section including a catalyst feed part (Tx) and dew point (Tz) of a mix gas in the reactor is 0 to 5° C.

Abstract: The present invention relates to a polypropylene composition comprising comonomer units derived from ethylene in an amount of from 1.5 wt % to 35 wt %, and from at least one C5-12 alpha-olefin in an amount of from 1.0 mol % to 3.0 mol %, wherein the polypropylene composition has an amount of xylene solubles XS of at least 40 wt %, and the xylene solubles have an amount of ethylene-derived comonomer units of from 4.0 wt % to 70 wt %.

Abstract: The present invention relates to a process of producing an ethylene polymer composition in multiple stages, of which the first stage is preferably a slurry polymerization stage, in the presence of a catalyst system, comprising: a) a solid catalyst precursor, comprising a transition metal selected from titanium and vanadium; magnesium; a halide, optionally an electron donor; and a solid particulate material comprising an inorganic oxide, and wherein the median particle diameter, D50, of the solid catalyst precursor, based upon the total volume of solid catalyst precursor, is from 1 to 13 micrometers; and b) an organoaluminium compound.

Abstract: Provided is a process for preparing polystyrene having a weight average molecular weight (Mw) in the range of 120,000- 160,000 gmol, a polydispersity in the range of 4-6 and a melt flow rate of at least 40 g/10 minutes by feeding styrene into a reaction system through which the styrene passes as a component of a reaction mixture as it is polymerized, the reaction system including an initial reaction zone (100) and a downstream reaction zone (200), comprising the steps of: polymerizing styrene in the initial reaction zone to form polystyrene having a Mw of greater than 300,000 gmol and a polydispersity in the range 1,5-2.5, 10-30 wt. % of the styrene fed to the initial reaction zone being polymerized there,—and polymerizing styrene remaining in the reaction mixture in the downstream reaction zone, a chain transfer agent being mixed with the reaction mixture at the commencement of this reaction zone and optionally at one or more additional locations within this reaction zone.

Abstract: Resins suitable for rotomolded articles comprise a bimodal polyethylene copolymer comprising from 0.1 to 5 weight % of one or more C6-8 alpha olefins and the balance ethylene, comprising from 20 to 50 weight % of a higher molecular weight polymer component having an Mw greater than 120,000 and correspondingly from 80 to 50 weight % of a lower molecular weight polymer component having an Mw less than 100,000 having a density greater than 0.942 g/cc [but less than 0.965 g/cc] and a bent strip ESCR as determined by ASTM D 1693 in 100% Igepal® CO-630 (ethoxylated nonylphenols) for conditions A and B of greater than 1000 hours. The resulting articles have a very good balance of properties and significant ESCR.

Abstract: An ethylene polymerization system is provided with a quench system and that cools the product mixture entering the separation system with a reduced load on the first compressor of the system. The system includes first and second compressors, a high pressure reactor; a high pressure let down valve through which the product mixture from the high pressure reactor flows, and a separation system that separates gas from the product mixture. The quench system includes a pump having a suction inlet that receives all or substantially all of the low pressure flow of monomer from the first compressor. The system provides quenching of the product stream while allowing the first compressor to be operated at a discharge pressure lower than the suction pressure of the second compressor, thereby conserving energy.