Abstract: In a gas phase olefin polymerization process using a fluidized bed vessel, an apparatus is employed having a device for measuring temperature or temperature distribution on the external wall surface of the vessel and a controlling means which predicts the progressive state of reaction inside the vessel, calculates the difference between the measured value and a target value determined beforehand and modifies polymerization conditions in relation thereto.

Abstract: Provided is a process for polymerizing olefins in the presence of a metallocene catalyst compound having at least one fluoride or fluorine containing leaving group. More particularly, the present invention is directed to a process and catalyst composition having improved reactor performance, reducing or eliminating the need for anti-fouling additives to the catalyst composition and/or the reactor. In one embodiment, the invention is a process of polymerizing olefins comprising contacting ethylene and at least one comonomer with a supported catalyst system comprising a metallocene catalyst compound, the metallocene catalyst compound comprising at least one fluoride ion or fluorine containing leaving group; and wherein the supported catalyst system comprises an inorganic oxide support having an average particle size of from 35 ?m or less and a pore volume of from 1 to 2 cm3/g. The polymer product resulting therefrom is, in one embodiment, a copolymer having a density in the range of from 0.910 g/cm3 to 0.

Abstract: A process for preparing and controlling the density of high density polyethylene in the gas phase comprising contacting ethylene or a mixture of ethylene and one or more alpha-olefins with a chromium oxide catalyst supported on a granular or microspherical refractory oxide in a fluidized bed reactor in the presence of oxygen.

Abstract: A process for producing a polyolefin according to the present invention comprises (co) polymerizing one or two or more ?-olefins in a vapor phase in a fluidized-bed reactor, wherein the concentration of (A) a saturated aliphatic hydrocarbon in the fluidized bed reactor is 1 mol % or more and at least one compound selected from (B) an aliphatic amide and (C) a nonionic surfactant constituted only of carbon, oxygen and hydrogen atoms is made to exist in the reactor. The present invention can provide a process for producing a polyolefin, the process ensuring that the prevention of clogging caused by the generation of sheet or block polymers and a high efficiency of the production of a polyolefin due to good catalytic activity can be accomplished at the same time and also having superb continuous productivity.

Abstract: The present invention is a process and an apparatus for the gas phase polymerization of olefin(s) using a fluidised-bed reactor (1) from which, at the top part, is withdrawn a recycling gas stream which comprises unreacted gas and entrained solid particles and which is moved by virtue of a compressor (4), which is cooled by passing into a heat exchanger (7) and which is reintroduced into the reactor at the bottom part (1a) of the latter. The heat exchanger (7) is a multitubular exchanger successively comprising an inlet chamber (6), a bundle of tubes (9) with a horizontal longitudinal axis and an outlet chamber (10) equipped with a discharge orifice (11).

Abstract: A process that can be used for direct esterification of a dicarboxylic acid such as terephthalic acid with a glycol such as 1,3-propanediol. The process comprises (1) contacting, at an elevated temperature, optionally in the presence of a preformed oligomer, the acid with the glycol to produce a product mixture comprising (i) a water-glycol vapor mixture, which or a portion of which exits the product mixture at the temperature to form a water-glycol vapor mixture and (ii) a liquid product mixture comprising an oligomer having a degree of polymerization of from about 1.9 to about 3.5 and comprising repeat units derived from the acid; (2) separating the glycol from the water-glycol mixture to produce a recovered glycol; and (3) returning the recovered glycol to the product mixture such that the liquid product mixture comprises an excess free glycol.

Abstract: The present invention relates to a continuous process for controlling the gas-phase co-polymerisation of olefins in a fluidised bed reactor. The present invention further relates to a method for the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor in the presence of a polymerisation catalyst wherein the density of the polymer powder particles leaving the reactor is maintained constant by controlling the particle size distribution of the polymerisation catalyst. The present invention also relates to a process for controlling the particle size distribution of a polymerisation catalyst in order to achieve the production of a polymer powder of constant density during the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor.

Abstract: The invention relates to processes and plants for continuous solution polymerization. Such plant and processes include a pressure source, a polymerization reactor, downstream of said pressure source, pressure let-down device, downstream of said polymerization reactor, and a separator, downstream of said pressure let-down device, wherein said pressure source is sufficient to provide pressure to said reaction mixture during operation of said process plant to produce a single-phase liquid reaction mixture in said reactor and a two-phase liquid-liquid reaction mixture in said separator in the absence of an additional pressure source between said reactor and said separator.

Abstract: The present invention concerns a high melt strength propylene polymer or copolymer suitable for manufacturing foams and thermoformed product exhibiting a melt strength of at least 3 g and comprising a high molar mass portion and a low or medium molar mass portion. The polymers are produced by subjecting propylene and optionally other olefins to polymerization in a plurality of polymerization reactors connected in series, employing different amounts of hydrogen as a molar mass modifier in at least two of the reactors, and carrying out the polymerization reaction in the presence of a catalyst system capable of catalyzing the formation of a high molar mass polymerization product having a MFR2 of less than 0.1 g/l0 min and a low or medium molar mass polymerization product having a MFR2 of more than 0.5 g/10 min.

Abstract: The present invention provides such a production process that a low-cost water-absorbent resin having excellent quality can be obtained by reasonable steps in aqueous solution polymerization. The production process for a water-absorbent resin comprises a polymerization setup that includes the steps of: supplying an aqueous solution of a water-soluble unsaturated monomer component including a major proportion of acrylic acid and/or its salt into a polymerization vessel causing shearing action; and then carrying out polymerization, involving crosslinking, of the water-soluble unsaturated monomer and at the same time carrying out fine division of the resultant hydrogel; with the production process being characterized in that the aqueous solution of the water-soluble unsaturated monomer component as supplied into the polymerization vessel has a temperature of not lower than 40° C.

Abstract: A process for polymerizing monomers in the gas phase, in fluidized bed reactors is described, where unsaturated, gas phase monomers are fed into the reactors in the presence of a mixture of inert diluents having a composition that allows the dew point to be adjusted, this leading to high production rates under stable operation in a non condensed operation mode.

Abstract: A process/apparatus is disclosed for continuously separating a liquid medium comprising diluent and unreacted monomers from a polymerization effluent comprising diluent, unreacted monomers and polymer solids, comprising a continuous discharge of the polymerization effluent from a slurry reactor through a discharge valve and transfer conduit into a first intermediate pressure flash tank with a conical bottom defined by substantially straight sides inclined at an angle to that of horizontal equal to or greater than the angle of slide of the slurry/polymer solids and an exit seal chamber of such diameter (d) and length (l) as to maintain a desired volume of concentrated polymer solids/slurry in the exit seal chamber such as to form a pressure seal while continuously discharging a plug flow of concentrated polymer solids/slurry bottom product of the first flash tank from the exit seal chamber through a seal chamber exit reducer with inclined sides defined by substantially straight sides inclined at an angle to th

Abstract: Methods of monitoring and controlling polymerization reactions are disclosed. The ratio of concentrations of two reactor components are determined in a gas stream of a reactor to obtain a leading indicator function L. The value of L or a function of L, such as a rescaled value or a reciprocal, is compared to a target value, and at least one reactor parameter is adjusted in response to a deviation between L or the function of L and the target value. Monitoring of the leading indicator permits rapid diagnosis of reactor problems, and rapid adjustments of reactor parameters, compared to laboratory analysis of samples of polymer properties.

Abstract: A flow reactor for liquid-phase polymerization reaction, which enables controlling the degree of polymerization for, for example, amino acid polymerization, wherein the liquid reaction mixture containing the organic reactive molecules to be polymerized is emitted from a high-temperature high-pressure part (A) to a low-temperature high-pressure part (B) via a circulation line (C), whereby inhibiting the decomposition of the polymer product in the low-temperature high-pressure part (B), after which the polymer product is once again sent to the high-temperature high-pressure part (A) through the circulation line for further polymerization, and the same cycle is repeated.

Abstract: The present invention provides a method for manufacturing an ethylene-vinyl acetate copolymer (EVA) in a polymerization solution in a vessel. The polymerization solution includes ethylene, vinyl acetate, methanol and a polymerization initiator. This method includes: cooling a gas including a vapor evaporated from the polymerization solution whereby to produce a condensate of at least a portion of said gas, and introducing said condensate into the polymerization solution whereby to evaporate at least one component in said condensate. Said vapor includes said at least one component.

Abstract: An improved process for the polymerisation of olefin monomer selected from (a) ethylene, (b) propylene, (c) mixtures of ethylene and propylene and (d) mixtures of (a), (b) or (c) with one or more alpha-olefins in a fluidised bed gas phase reactor, said process comprising passing a gaseous mixture of said olefin monomers(s) through the fluidised bed under effective polmerisation conditions to provide a polymer product containing unreacted monomer(s) and a gaseous effluent stream comprising unreacted monomer(s), removing the polymer product to a degassing vessel, recycling a first portion of the gaseous effluent stream to the fluidised bed and passing a second portion of the gaseous effluent stream to counter currently contact the polymer product in said degassing vessel to produce a polymer product having a reduced amount of unreacted monomer(s), characterised in that the improvements to the process comprise: (i) removing heavy hydrocarbons from the second portion of the effluent stream and returning said hydr

Abstract: A method of producing a vinyl chloride-based polymer by suspension polymerization is provided, by which heat removal performed by a reflux condenser can be increased, but total heat removal performed by the jacket can be reduced, without affecting the quality of the product polymer. The method includes commencing heat removal when or after a polymerization conversion rate reaches 15%, and controlling said reflux condenser so as to remove a fixed quantity of heat per unit of time depending on the polymerization conversion rate as the polymerization process proceeds.

Abstract: The process for polymerizing olefins uses a plurality of series-connected polymerization reactors in which at least one of second and subsequent reactors is a vapor-phase polymerization reactor containing a multicomponent gas. The process comprises the steps of: taking the multicomponent gas out of the vapor-phase polymerization reactor; mixing the multicomponent gas with an inert gas which is lighter than at least one component of the multicomponent gas, thereby obtaining a mixed gas; compressing and/or cooling the mixed gas to liquefy a part of the multicomponent gas; discharging at least a part of a gaseous mixture comprising the inert gas and an unliquefied multicomponent gas out of a reaction system; and returning a fluid comprising the remainder of the gaseous mixture and the liquefied multicomponent gas to the vapor-phase polymerization reactor.

Abstract: A recycling and recovery system and process comprising a flash gas separator that receives a slurry comprising liquid medium and solid polymer particles. The flash gas separator separates the diluent from the solid polymer particles as a vapor stream comprising at least diluent and heavies. A line receives the vapor stream from the flash gas separator. The line leads to a heavies removal system that yields a liquid that is relatively concentrated in heavies and a diluent vapor that is relatively free of heavies. The liquid is passed to a heavies column, while the diluent vapor is passed to a diluent recycle chamber and then recycled to a slurry polymerization reactor without additional treatment to remove heavies.

Abstract: The partially condensed fluid recycle stream of a fluidized bed polyolefin reactor operating in the condensing mode is split into two portions by a stream splitter. In a preferred mode, the smaller stream from the splitter contains a higher ratio of liquid to gas than the larger stream. One portion of the split stream is injected below the fluidized bed and the other, preferably with enhanced liquid content, is injected into the fluidized bed at a level above the product withdrawal level. Regulation of liquid injection above the product withdrawal level, as a function of liquid in the product discharge tanks, reduces the liquid in the product discharge system, resulting in improved discharge cycle times and more efficient conservation of monomer and other materials which might otherwise be lost in the discharge process.

Abstract: For producing homopolymers or copolymers of propylene in the gas phase, gaseous or liquid monomers are introduced into a polymerization zone; the pressure and temperature in the polymerization zone are kept within a range that corresponds to the gaseous state of the monomers; gaseous monomers not consumed by polymerization are discharged from the polymerization zone and liquefied and re-introduced in liquid form into the polymerization zone. The temperature regulation in the polymerization zone is done by means of continuous measurement of the temperature and a change, tripped upon a change in temperature, in the quantity of liquid monomers introduced per unit of time into the reaction zone. To that end, the temperature is measured at a plurality of points vertically offset from one another, and from the respective measured values a respective mean value is formed.

Abstract: A method and an apparatus of discharging polymer from a continuously operated gas phase reactor, wherein at least one monomer is polymerized in a bed containing active catalyst formed by catalyst and polymer particles suspended in a fluid, the bed defining a fluidized bed level in said reactor. The invention comprises continuously withdrawing polymer powder from the reactor; and adjusting the discharge rate of the polymer powder so as to maintain a constant bed level during polymerization. By means of the invention the discharge of the polymer can be made truly continuous without any disturbance of the polymerization. The rate of withdrawn polymer can be flexibly adjusted depending on the progress of the polymerization and it can also easily be scaled up if the capacity of the reactor is increased.

Abstract: A process for preparing polyethylene from “feed ethylene” comprises: a) a hydrogenation stage in which “feed ethylene” containing impurities or secondary components such as acetylene and ethane is reacted with hydrogen to remove the acetylene by catalytic hydrogenation to form ethylene and part of the ethylene is converted into ethane, and b) a polymerization stage in which the ethylene leaving stage a) is reacted in the gas phase in a fluidized-bed reactor to form polyethylene, where the fluidizing gas used comprises, on entering the reactor, ethene and from 20 to 70% by volume of ethane, based on the total volume of the fluidizing gas, possibly together with further components, where, in a), ethylene is converted in a targeted manner into ethane in addition to the ethane already present in the “feed ethylene” so that the concentration specified in b) results. An apparatus for carrying out the process is also provided.

Abstract: A process for preparing copolymers via free-radical-initiated polymerization of one or more vinyl esters, ethylene, and also, where appropriate, other ethylenically unsaturated monomers copolymerizable therewith, at a pressure of from 5 to 100 bar abs., in an aqueous medium, by emulsion or suspension polymerization, which comprises, after termination of the polymerization, reclaiming residual unreacted ethylene by depressurizing the polymerization reaction mixture to a pressure of from 0.1 to 5 bar absolute, comprising a gas phase containing residual ethylene gas to a pressure of from 2 to 20 bar absolute, absorbing the gas phase into vinyl ester(s), and reusing the resulting solution of ethylene in vinyl esters(s) in a further polymerization.

Abstract: Process of producing polytrimethylene terephthalate (PTT) by esterification of terephthalic acid (TPA) with trimethylene glycol (TMG) in the presence of a catalytic, titanium compound, precondensation and polycondensation. The esterification is effected in at least two stages, where in the first stage a molar ratio of TMG to TPA of 1.25 to 2.5, a content of titanium of 0 to 40 ppm, a temperature of 245 to 260° C. as well as a pressure of 1 to 3.5 bar are adjusted. In the at least one subsequent stage a content of titanium is adjusted which is higher than in the initial stage by 35 to 110 ppm. For generating the vacuum in the polycondensation and in the precondensation, there are used vapor jet pumps operated with TMG vapor.

Abstract: The present invention relates to a continuous process for controlling the gas-phase co-polymerisation of olefins in a fluidised bed reactor. The present invention further relates to a method for the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor in the presence of a polymerisation catalyst wherein the density of the polymer powder particles leaving the reactor is maintained constant by controlling the particle size distribution of the polymerisation catalyst. The present invention also relates to a process for controlling the particle size distribution of a polymerisation catalyst in order to achieve the production of a polymer powder of constant density during the continuous gas-phase (co-)polymerisation of olefins in a fluidised bed reactor.

Abstract: An aqueous semi-continuous emulsion polymerization process for producing bimodal polymer particles in volumes large than a single batch size is provided. A bimodal polymer composition prepared by the process of carrying out an aqueous semi-continuous emulsion polymerization is also provided.

Abstract: The invention relates to continuous gas fluidized bed methods for making a polymer featuring a condensing agent in a recycle stream; and also to methods for monitoring and providing continuity in a gas fluidized bed method for making a polymer featuring a condensing agent in a recycle stream. Certain ranges of &Dgr;&rgr;, in some cases combined with certain ranges of values for An, can be used to find and define desirable operating states, i.e., the “steady state,” “alert state,” “corrective action state,” “continuity impairment state” and/or “&Dgr;&rgr; alarm state,” for the gas fluidized bed reactor polymerization method (where &Dgr;&rgr;, An and the particular states are disclosed herein).

Abstract: The invention relates to a method for the continuous production of ethylene homo- and ethylene co-polymers in the presence of radical polymerisation initiators and, optionally, molecular weight regulators in a tubular reactor with a hot water jacket and one or several reaction zones at pressures of 1000 to 4000 bar and temperatures of 120° C. to 350° C. The hot water jacket of each reaction zone is divided into two independently-controllable, separate, longitudinal sections and the water exit temperature from the tubular jacket of the first longitudinal section per reaction zone, extending between the point of initiator addition and 20 to 50% of the reaction zone length, is set to 180° C. to 210° C. and in the following second longitudinal section of said reaction zone the hot water exit temperature from the tube jacket is set to 140° C. to 180° C.

Abstract: A process for the single-stage preparation of polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of from 650 to 5000 dalton by polymerization of tetrahydrofuran over a heterogeneous acid catalyst in the presence of at least one telogen and/or comonomer selected from the group consisting of alpha,omega-diols, water, polytetrahydrofuran having a molecular weight of from 200 to 700 dalton and cyclic ethers comprises a) separating off the catalyst and/or downstream products of the catalyst suspended and/or dissolved in the output from the polymerization, b) fractionating the resulting catalyst-free output from the polymerization in at least one distillation step to give a distillation residue comprising the polymerization product and at least one tetrahydrofuran fraction and returning at least part of the tetrahydrofuran fraction to the polymerization and c) separating low molecular weight polytetrahydrofuran and/or tetrahydrofuran copolymers having a mean molecular weight of

Abstract: An improvement to the melt transesterification reaction of diaryl carbonate with dihydroxy aryl compound is disclosed.

Abstract: The present invention relates to an apparatus and a process for locating and for measuring variations in temperature and/or in degree of fouling over the internal suface of equipment

Abstract: An aqueous semi-continuous emulsion polymerization process for producing bimodal polymer particles in volumes large than a single batch size is provided. A bimodal polymer composition prepared by the process of carrying out an aqueous semi-continuous emulsion polymerization is also provided.

Abstract: The present invention relates to a process for polymerizing &agr;-olefins in at least two stages, the first stage comprising at least one bulk reactor and optionally at least one gas phase reactor for forming the &agr;-olefin polymer matrix and the second stage comprising at least one additional gas phase reactor for copolymerization of ethylene with said polymer matrix. In the second stage an antifouling composition is fed into said gas phase reactor(s) for preventing fouling in the second stage.

Abstract: Tubular reactor apparatus and processes are provided for improved polymerization including using chain transfer agents and multiple monomer feeds spaced lengthwise along the tubular reactor providing high conversions of monomer into polymer. The invention also relates to polymers made from such a tubular reactor apparatus and processes including those polymers having a low haze value, a density over 0.92 g/cm3 and/or having terminal carbonyl groups. The apparatus and methods uncouple or reduce the dependency between the monomer concentration and transfer agent concentration. The uncoupling in other embodiments may also be varied leading to multiple desirable effects.

Abstract: A process/apparatus is disclosed for continuously separating a liquid medium comprising diluent and unreacted monomers from a polymerization effluent comprising diluent, unreacted monomers and polymer solids, comprising a continuous discharge of the polymerization effluent from a slurry reactor through a discharge valve and transfer conduit into a first intermediate pressure flash tank with a conical bottom defined by substantially straight sides inclined at an angle to that of horizontal equal to or greater than the angle of slide of the slurry/polymer solids and an exit seal chamber of such diameter (d) and length (l) as to maintain a desired volume of concentrated polymer solids/slurry in the exit seal chamber such as to form a pressure seal while continuously discharging a plug flow of concentrated polymer solids/slurry bottom product of said first flash tank from the exit seal chamber through a seal chamber exit reducer with inclined sides defined by substantially straight sides inclined at an angle to t

Abstract: Provided is a process for polymerizing olefins in the presence of a metallocene catalyst compound having at least one fluoride or fluorine containing leaving group. More particularly, the present invention is directed to a process and catalyst composition having improved reactor performance, reducing or eliminating the need for anti-fouling additives to the catalyst composition and/or the reactor. In one embodiment, the invention is a process of polymerizing olefins comprising contacting ethylene and at least one comonomer with a supported catalyst system comprising a metallocene catalyst compound, the metallocene catalyst compound comprising at least one fluoride ion or fluorine containing leaving group; and wherein the supported catalyst system comprises an inorganic oxide support having an average particle size of from 35 &mgr;m or less and a pore volume of from 1 to 2 cm3/g. The polymer product resulting therefrom is, in one embodiment, a copolymer having a density in the range of from 0.910 g/cm3 to 0.

Abstract: Disclosed is a system of making an olefin derivative from a dilute olefin feed. Dilute olefin is sent to an olefin reaction unit to form an olefin derivative product. The olefin derivative product is recovered from the reaction unit while a vent stream is also removed. Olefin is separated from the vent stream, and the olefin is sent to the olefin reaction unit for additional processing.

Abstract: The present invention relates to a nozzle for the injection of a liquid under pressure (3), comprising a vertical feed pipe (1) surmounted by a hollow head (3), the liquid under pressure being conducted between the outer wall (4) of the vertical feed pipe (1) and an inner tube (5), the upper part of the nozzle comprising at least one lateral orifice (6) for expelling the liquid under pressure (3).

Abstract: A process for the gas-phase (co-)polymerization of olefins in a fluidized bed reactor using a chromium oxide catalyst. The polymerization is performed in the presence of a process aid additive.

Abstract: The present invention relates to a polymerization process in the presence of a bulky ligand metallocene-type catalyst compound having an abstractable fluoride or fluorine containing leaving group.

Abstract: A process for producing a polyolefin according to the present invention comprises (co) polymerizing one or two or more &agr;-olefins in a vapor phase in a fluidized-bed reactor, wherein the concentration of (A) a saturated aliphatic hydrocarbon in the fluidized bed reactor is 1 mol % or more and at least one compound selected from (B) an aliphatic amide and (C) a nonionic surfactant constituted only of carbon, oxygen and hydrogen atoms is made to exist in the reactor. The present invention can provide a process for producing a polyolefin, the process ensuring that the prevention of clogging caused by the generation of sheet or block polymers and a high efficiency of the production of a polyolefin due to good catalytic activity can be accomplished at the same time and also having superb continuous productivity.

Abstract: A process for the continuous gas-phase (co)polymerization of one or more olefins for which a rising stream of a gas mixture, comprising at least one olefin to be (co)polymerized, maintains polymer particles in the course of formation in the fluidized state in a polymerization reactor, the said stream entraining fine particles above the fluidized bed outside the reactor, the said fine particles being substantially separated from the gas mixture using a separator, thus dividing the said stream into (i) one or more gas streams (A) substantially devoid of solid particles which is cooled and reintroduced below and/or into the bottom part of the fluidized bed, and (ii) one or more gas streams (B) comprising at least a portion of the said particles which is introduced into or above the fluidized bed, which process is characterized in that at least one of the gas streams (B) comprising the solid particles is introduced directly into the fluidized bed by a dilute-phase transport in a simple pipe, that is to say prefer

Abstract: The present invention relates to a process for preparing high density polyethylene in the gas phase comprising contacting ethylene or a mixture comprising ethylene and one or more alpha-olefins with a chromium oxide catalyst supported on a granular or microspherical refractory oxide in a fluidised bed reactor in the presence of oxigen. The present invention further relates to a process for controlling the density of high density polyethylene prepared in the gas phase comprising contacting ethylene or a mixture comprising ethylene and one or more alpha-olefins with a chromium oxide catalyst supported on a granular or microspherical refractory oxide in a fluidised bed reactor in the presence of oxigen.

Abstract: A process for polymerizing monomers in the gas phase, in fluidized bed reactors is described, where unsaturated, gas phase monomers are fed into the reactors in the presence of a mixture of inert diluents having a composition that allows the dew point to be adjusted, this leading to high production rates under stable operation in a non condensed operation mode.

Abstract: A process is disclosed for a continuous, high temperature polymerization process for preparing a free radically polymerized epoxy-functional polymeric product. The process comprises continuously charging into a reactor at least one epoxy-functional acrylic monomer, and optionally at least one non-functional free radical polymerizable monomer. An optional free radical polymerization initiator may also be added. The reactor is maintained at an effective temperature for an effective period of time to cause polymerization of the monomers into a polymeric product, such that the polymeric product is formed substantially free of gel particles. A clear coating is also disclosed incorporating polymers of the present invention, such that the clear coating has a low Delta b value at standard conditions.

Abstract: The invention relates to a method and an apparatus for the polymerization of gaseous olefins, in particular of ethylene and at least one &agr;-olefin, in the gas phase in a stirred or fluidized, catalyst-containing polymerization zone (2) and at least one decompression zone (6, 10) downstream of the polymerization zone (2). The mixture of solid (co)polymer and unreacted monomers leaving the polymerization zone (2) flows through a settling zone, in particular in the form of a settling leg (14), before the decompression zone.

Abstract: A process for controlling a continuous fluidised bed reactor (co-)polymerisation process which comprises (1) withdrawing from the reactor a hot recycle stream containing a principal monomer and at least one other unreacted reactant, (2) cooling part or all of the recycle stream withdrawn from the reactor, and (3) recycling part or all of the cooled recycle stream containing the principal monomer and the unreacted reactant(s) through the polymerisation zone in the reactor in the presence of a polymerisation catalyst under reactive conditions, wherein the controlling process consists in maintaining at least one of the reactant gradients (Gri) within a range of values outside which sheeting or unstable operations would otherwise occur.

Abstract: Tubular reactor apparatus and processes are provided for improved polymerization including using chain transfer agents and multiple monomer feeds spaced lengthwise along the tubular reactor providing high conversions of monomer into polymer. The invention also relates to polymers made from such a tubular reactor apparatus and processes including those polymers having a low haze value, a density over 0.92 g/cm3 and/or having terminal carbonyl groups. The apparatus and methods uncouple or reduce the dependency between the monomer concentration and transfer agent concentration. The uncoupling in other embodiments may also be varied leading to multiple desirable effects.

Abstract: This application discloses triphenyl carbenium NCA's as catalyst activators for a class of asymmetrically bridged hafnocene catalyst precursors. These catalyst precursors are activated into olefin polymerization catalysts and are suitable for gas, solution, and slurry-phase polyermization reactions. The disclosed bridge is methylenyl- or silanylenyl-based and is optionally, alkyl or aryl substituted. The catalytic activity of the disclosed hafnocene catalyst precursors is substantially enhanced over identical catalysts that are activated with other activators.

Abstract: Disclosed is a method and apparatus for continuously forming and depositing a layer of monomolecular amphiphilic molecules on a substrate. The present invention includes an apparatus and method for transferring and compressing an uncompressed molecular layer from one liquid surface region in a tank to another adjacent liquid surface region by using non-moving or static mechanical components which do not come into direct contact with the monomolecular layer. The present invention includes a method and apparatus which permit the continuous and simultaneous draining and replenishing of the liquid in the tank while maintaining the liquid surface level constant. The continuous replacement of the liquid in the tank with clean liquid reduces the level of contamination of the liquid in the tank. In addition, the level, as well as the type of contamination of the liquid, does not vary significantly with time.