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: Processes for transitioning among polymerization catalyst systems, preferably catalyst systems that are incompatible with each other. In particular, the processes relate to transitioning among olefin polymerization reactions utilizing Ziegler-Natta catalyst systems, metallocene catalyst systems and other MAO-based single site catalyst systems.

Abstract: The present invention relates to a process for the gas-phase (co-)polymerization of olefins in a fluidised bed reactor using a late transition metal catalyst characterised in that the polymerization is performed in the presence of a process aid additive.

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for the gas phase polymerization of olefin(s) using a fluidised-bed reactor (1) from which, at the top part, is withdrawn a recycling gas stream which comprises unreacted gas and entrained solid particles and which is moved by virtue of a compressor (4), which is cooled by passing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 for the gas-phase (co-)polymerization of olefins in a fluidised bed reactor using a Ziegler-Natta type catalyst characterised in that the polymerisation is performed in the presence of an additive having the formula R—Cl where R is an alkyl group of 2 to 7 carbon atoms.

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: A multimodal polymer composition for pipes is disclosed. The polymer is a multimodal polyethylene with a density of 0.930-0.965 g/cm3, an MFR5 of 0.2-1.2 g/10 min, an Mn of 8000-15000, an Mw of 180-330×103, and an Mw/Mn of 20-35, said multimodal polyethylene comprising a low molecular weight (LMW) ethylene homopolymer fraction and a high molecular weight (HMW) ethylene copolymer fraction, said HMW fraction having a lower molecular weight limit of 3500, and a weight ratio of the LMW fraction to the HMW fraction of (35-55):(65:45).

Abstract: The present invention is a process for transitioning from a first polymerization reaction to a second polymerization reaction incompatible with the first polymerization reaction in a gas-phase reactor. The novel process comprises conducting multiple polymerization reactions, capturing and storing a substantially contaminant-free polymerization product from each multiple polymerization reaction for use as a selected substantially contaminant-free seedbed in a second polymerization, wherein the polymerization product from each multiple polymerization reaction is rendered substantially contaminant-free by stripping or venting reactants and contaminants and is maintained as substantially contaminant-free by storage under an inert atmosphere.

Abstract: The present invention relates to the use of thermally triggered compounds that when used with a polymerization catalyst in a polymerization process results in the controllable generation of one or more catalyst inhibitors that renders the polymerization catalyst substantially or completely inactive.

Abstract: This invention relates to processes for transitioning among polymerization catalyst systems, preferably catalyst systems, which are incompatible with each other. Particularly, the invention relates to processes for transitioning among olefin polymerization reactions utilizing Ziegler-Natta catalyst systems, metallocene catalyst systems and chromium-based catalyst systems.

Abstract: A method for controlling resin properties during the production of polyolefins is provided. The method utilizes coordinated manipulation of reaction temperature in combination with a secondary process variable to control resin flow properties to rapidly respond to manufacturing upsets or specification changes to minimize off-grade or transition polymer material when moving from one polymer grade to another, or during a disturbance in a steady state production.

Abstract: Processes for transitioning among polymerization catalyst systems, preferably catalyst systems, which are incompatible with each other. Particularly, processes for transitioning among olefin polymerization reactions utilizing silyl-chromate catalyst systems and metallocene catalyst systems.

Abstract: The present invention is a process for transitioning from a first polymerization catalyst system to a second polymerization catalyst system incompatible with the first polymerization catalyst system in a gas-phase reactor. The novel process comprises conducting a first polymerization reaction using a first polymerization catalyst system; stopping the first polymerization reaction; removing the contents of the first polymerization reaction from the reactor while maintaining a substantially closed system; then, in the substantially closed system, introducing a substantially contaminant free seedbed into the reactor; introducing a second feed system and a second catalyst system into the reactor; and conducting a second polymerization reaction.

Abstract: This invention relates to a polymerization method comprising contacting at least one olefin monomer, at least one polar monomer, an optional activator, and a catalyst compound represented by the formula: 1

Abstract: A process of transitioning from a first polymerization reaction conducted in the presence of a mixed catalyst system to a second polymerization reaction conducted in the presence of a chrome-based catalyst system is disclosed, the polymerization reactions being conducted in one embodiment in a polymerization zone of a gas phase fluidized bed reactor which contains a fluidized bed of polymer particles by the essentially continuous passage of monomer gases through the polymerization zone, comprising: a) discontinuing the introduction of the mixed catalyst system into the reactor; b) maintaining polymerization conditions in the reactor and permitting polymerization to continue for a period of time to allow the components of the mixed catalyst system present in the reactor to produce additional polymer particles; c) introducing a deactivating agent into the fluidized bed in an amount sufficient to deactivate the mixed catalyst system; d) establishing optimal conditions within the reactor for the chrome-based

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: The invention relates to a method for evaluating the condition of a fluidized bed reactor by examining the condition of the reactor wall. Specifically, the invention relates to a method for measuring static in the reactor using a static probe that is located at the distributor plate and comprises a distributor plate cap. The invention also relates to methods of determining a static level using a radio frequency (rf). The static measurements are provided to indicate or predict major continuity disturbances in the fluidized bed gas phase reactor.

Abstract: The invention provides a catalyst system and a method of making polyethylene using the catalyst system, the method comprising combining ethylene; an activator; and a metallocene catalyst compound; wherein in one embodiment the metallocene catalyst compound is selected from: 1

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: Some properties such as dart impact strength, hexane extractables and resin stickiness of a polyethylene copolymer produced in a gas phase polymerization using a Ziegler-Natta catalyst are better controlled by regulating the ratio of aluminum from the co-catalyst to the polymer production rate. This enables one to improve properties such as dart impact strength and reduce hexane extractables by changing the amount of co-catalyst fed into the reactor.

Abstract: Continuous gas-phase polymerization process for preparing ethylene and propene homopolymers and copolymers, in which ethylene, propene or mixtures comprising ethylene or propene and C3-C8-&agr;-monoolefins are polymerized in the polymerization zone of a gas-phase polymerization reactor at from 30 to 125° C. and pressures of from 1 to 100 bar in the gas phase in a bed comprising finely divided polymer in the presence of a catalyst. To remove the heat of polymerization, the reactor gas is circulated and firstly passes through a cyclone after leaving the reactor. To prevent polymer deposits in the circulating gas system, a catalyst poison having a boiling point above the maximum temperature within the circulating gas system is fed into this circulating gas system at a position between the reactor and the cyclone.

Abstract: The object of the present invention is to provide a polyolefin polymerization method which prevents fine particles of polymer from scattering from a fluidized bed in a gas phase polymerization reactor.

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: An apparatus for gas-phase catalytic polymerization comprising a first vertical reactor (1), a second vertical reactor (2), the upper region of said reactor (1) being connected by a connecting part (3) to a solid as separator (4), which is in turn connected to the upper region of second reactor (2), the lower region of second reactor (2) being connected to the lower region of first reactor (1) by a connecting part (5), the solid/gas separator (4) being connected through a recycle line (6) to one or more points of reintroduction into connecting part (5) or into reactor (1), the apparatus having a line (12) for feeding catalyst into reactor (1), a polymer discharge system (11) from reactor (2), a line (13) for feeding monomers, the apparatus being further characterized in that it comprises a line (15) for feeding gas or liquid into reactor (2).

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 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 of transitioning from a first polymerization reaction conducted in the presence of a mixed catalyst system comprising to a second polymerization reaction conducted in the presence of a chrome-based catalyst system is disclosed, the polymerization reactions being conducted in one embodiment in a polymerization zone of a gas phase fluidized bed reactor which contains a fluidized bed of polymer particles by the essentially continuous passage of monomer gases through the polymerization zone, comprising:

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: The invention encompasses late transition metal catalyst systems immobilized on solid supports and their use in heterogenous polymerization processes, particularly in gas phase polymerization of olefin monomers. Preferred embodiments include a late transition metal catalyst system comprising a Group 9, 10, or 11 metal complex stabilized by a bidentate ligand structure immobilized on a solid porous metal or metalloid oxide particle support, particularly those comprising silica. The gas phase polymerization process for olefin monomers comprises contacting one or more olefins with these catalyst systems under gas phase polymerization conditions.

Abstract: The propylene polymer of the invention is transparent and has good low-temperature heat-sealability and scratch resistance, and is favorable to wrapping and packaging films. (1) The polymer has a melting point, Tm (° C.), measured through differential scanning calorimetry, of 110≦Tm≦140; (2) its heat of fusion &Dgr;H (J/g) and melting point Tm (° C.) satisfy &Dgr;H≧0.45×Tm+22; (3) the half-value width Th (° C.) of the peak top of its elution curve obtained in programmed-temperature fractionation is Th≦5; and (4) its intrinsic viscosity [&eegr;] (dl/g) measured in a solvent of tetralin at 135° C. falls between 0.5 and 5.

Abstract: The invention relates to a catalyst component and a catalyst system for the preparation of high molecular weight ethylene or alpha-olefin homopolymers, ethylene-alpha-olefin copolymers, terpolymers or tetrapolymers, in a polymerization process, which is expediently effected in solution, at elevated temperature, preferably at least 80 DEG C. The catalyst system comprises a group 4-6 metal, preferably group 4 metal, a cyclic ligand (such as a cyclopentadienyl-type ligand), which forms a delocalized pi-bond with the metal M, a monohapto bonded 1,3-diaza-2-imino heterocyclic ligand (such as an iminoimidazolidine-type ligand) and anionic ligands and a catalyst activator coupound.

Abstract: A polymerization process with elevated productivity using a coordination catalyst, wherein electromagnetic radiation is applied during polymerization. The irradiation of light greatly increases the activity of the coordination catalyst.

Abstract: The use of olefin feedstocks with low carbon monoxide content to achieve improved productivities in nickel catalyzed olefin polymerizations is described.

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: Processes for transitioning among polymerization catalyst systems, preferably catalyst systems that are incompatible with each other. In particular, the processes relate to transitioning from olefin polymerizations utilizing metallocene catalyst systems to olefin polymerizations utilizing traditional Ziegler-Natta catalyst systems.

Abstract: The present invention provides a catalyst for olefin polymerization having high olefin polymerization activity without being accompanied by generation of an adhered polymer on the wall of a polymerization reactor and the wall of pipe line and generation of a blocking massive polymer, and capable of manufacturing an olefin polymer industrially and stably for a long period of time.

Abstract: The invention provides for polymerization catalyst compositions, and for methods for introducing the catalyst compositions into a polymerization reactor. More particularly, the method combines a catalyst component containing slurry and a catalyst component containing solution to form the completed catalyst composition for introduction into the polymerization reactor. The invention is also directed to methods of preparing the catalyst component slurry, the catalyst component solution and the catalyst compositions, to methods of controlling the properties of polymer products utilizing the catalyst compositions, and to polymers produced therefrom.

Abstract: This invention relates to a process for carrying out an anionically or cationically catalytically accelerated gas phase reaction and particularly relates to a process for carrying out a catalytically accelerated gas phase polymerization reaction. The process involves the step of introducing a catalyst ion into a gaseous reaction mixture as a free anion or cation without a corresponding counterion and substantially solvent free. The catalyst of this invention ca, for example, be a Ziegler-Natta catalyst or a metallocene catalyst. The gas phase reaction that is catalyzed can, for example, be a metathesis reaction, a metathesis ring-opening polymerization reaction, or a gas phase polymerization.

Abstract: Free-radical-initiated copolymerization of metallocene complexes containing olefinic substituents on aryl groups with styrene results in polymerized late transition metal catalysts that can be used for olefin polymerization or oligomerization. These catalysts have high catalyst activity for olefin polymerization or oligomerization.

Abstract: The invention discloses a solid catalytic component comprising a metallocene, at least one first ligand of which comprises a cyclopentadienyl group chemically bonded via a methyl group to a support composed of a porous inorganic compound. It also discloses a process for the preparation of such a solid catalytic component.

Abstract: Processes for transitioning among polymerization catalyst systems, preferably catalyst systems, which are incompatible with each other. Particularly, processes for transitioning among olefin polymerization reactions utilizing silyl-chromate catalyst systems and metallocene catalyst systems.

Abstract: This invention relates to processes for transitioning among polymerization catalyst systems, preferably catalyst systems, which are incompatible with each other. Particularly, the invention relates to processes for transitioning among olefin polymerization reactions utilizing Ziegler-Natta catalyst systems, metallocene catalyst systems and chromium-based catalyst systems.

Abstract: This invention relates to a polymer comprising one or more C3 to C40 olefins, optionally one or more diolefins, and less than 15 mole % of ethylene, where the polymer has:

Abstract: A novel continuous gas phase polymerization process for producing polyethylene and interpolymers of ethylene and at least one other olefin is provided wherein a non-aromatic halogenated hydrocarbon(s) is used in a specified amount such that the activity of the titanium, zirconium and/or hafnium containing Ziegler-Natta catalyst is increased.

Abstract: A gas phase polymerization process for producing a polyolefin composition is described, which includes passing a gaseous stream containing hydrogen gas and one or more monomers, including ethylene monomers, through a reactor that includes a fluidized bed, under reactive conditions, in the presence of a catalyst that includes metallocene, to provide a polyolefin composition, wherein in one embodiment the fluidized bulk density is 60% or more of the settled bulk density (or, a voidage of 40% or less); and wherein the voidage is controlled by a number of factors including, in certain embodiments, (a) the reactor temperature being maintained at 100° C. or below; (b) the molar ratio of hydrogen gas to ethylene introduced into the reactor being 0.015 or below.

Abstract: A process for early detection of reactor fouling occurring during a gas phase polymerization of olefin(s) using a fluidized bed reactor having a fluidization grid fitted with detection devices.

Abstract: Ethylene based polymers having high molecular weights can be obtained in high yields at temperatures of industrial interest, by carrying out the polymerization reaction in the presence of catalysts comprising silicon bridged metallocenes having a particular ligand system containing a heteroatom.

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.