Abstract: A method for controlling sheeting in a gas phase reactor that includes producing a polyolefin with at least one metallocene catalyst and at least one static control agent in at least one gas phase reactor, measuring entrainment static using a static probe, and adjusting the concentration of the static control agent in response to changes in the measured entrainment static is disclosed.

Abstract: The present technique provides for the use of spectroscopic probes, such as Raman probes, within the conduits of a polyolefin production system. The Raman probe or other spectroscopic probes may be used to obtain spectroscopic measurements of the contents of the conduits. The spectroscopic measurements may be processed and analyzed to determine the composition of the conduit contents. In addition, the spectroscopic measurements may be used in conjunction with correlations or other statistical models to determine one or more properties of interest of a constituent of the conduit contents. One or more processes upstream and/or downstream of the conduit may be adjusted in response to the determined composition or composition properties.

Abstract: The present invention relates to a process for improving the start up of polymerization or copolymerization of ethylene in a gas phase reactor, preferably a fluidised bed gas phase reactor.

Abstract: Die attach adhesives and methods for their use, along with the devices that are obtained by the use of the methods. Using semiconductor chips as an example, the adhesives and the method for using them provides an interface between a chip (die) and the chip support. The method includes creating a space between the chip and the chip support of a given sized opening.

Abstract: The present invention relates to a method of estimating the properties of a polymer product by using converted process variables (cPV's) which means process variable that final or intermediate product experienced earlier in average in the reactors by stage with respect to the final product, which incorporates residence time distribution to process variables, wherein said method comprises the following steps of: computing cPV's by incorporating the residence time distribution to said process variables by means of theoretically determining the amounts of content and discharge of the product in the process, and then solving the balance equations of a hypothetical substance by taking the respective process variables as those of the hypothetical substance: and estimating the properties of the product by inputting to various property estimation models cPV's in the reactors by stage with respect to the final product after incorporating the residence time distribution to said process variables.

Abstract: The present method is directed to techniques for estimating and periodically controlling the reactor split of alpha-olefin polymerizations using multiple catalysts that selectively incorporate monomers and other reactants into polymer compositions. The method provides for the rapid determination of instantaneous reactor split and cumulative split in polymerization reactors by the use of a novel linear relationship between Incorporation and Reactor Split.

Abstract: A process for making a high molecular weight (co)polycarbonate resin is disclosed. The process entails (i) obtaining at least one member selected from the group low molecular weight residue (weight average molecular weight 15,000 to 30,000) of aromatic (co)polycarbonate production, waste of (co)polycarbonate production, remainders of (co)polycarbonate production and (co)polycarbonate recyclate (ii) melting the said member in a suitable vessel to obtain a melt and (iii) feeding the melt into a reactor optionally along with at least one bisphenol or oligocarbonate having terminal OH groups and further optionally with a transesterification catalyst, and (iv) subjecting the melt to transesterification reaction at a temperature of 250 to 350° C., at a pressure below 5 mbar and residence time of 0.02-4 hours.

Abstract: Disclosed is a process for preparing a polymer. The process includes at least one process stream and the process stream has at least one characteristic of interest. The process further includes passing the process stream past a sensor probe connected to a near-IR spectrophotometer and passing light from a light source through the probe and into the spectrometer wherein the light source, spectrometer and sensor probe are connected by a fiber optic cable. The effect of the interaction of the process stream and the light passing through the senor probe is measured and used to define a value for the characteristic of interest. The value for the characteristic of interest is a component of an algorithm and the algorithm is used, in real time, to monitor, control, or monitor and control the process for preparing a polymer.

Abstract: Disclosed herein are processes for detecting the location of an interface between phases. In one embodiment, the process comprises: introducing a reaction mixture into a vessel wherein the reaction mixture is the product of an at least two phase interfacial reaction, and a difference in densities between at least two of the phases is less than or equal to about 1 g/cc, separating the reaction mixture into the phases with an interface located therebetween, measuring electrical inductance of the reaction mixture at different latitudinal locations; and determining the location of the interface.

Abstract: The present invention is relates to a process for the preparation of an isoolefin polymer containing repeating units derived from at least one isoolefin, at least one divinyl aromatic monomer and, optionally, additional copolymerizable monomers, wherein the content of unreacted vinyl groups from the aromatic monomer is predicted by means of FTIR measurements. The present invention is related to a process for the preparation of an isoolefin polymer comprising repeating units derived from at least one isoolefin, at least one divinyl aromatic monomer and, optionally, further copolymerizable monomers, wherein the content of unreacted vinyl groups from the aromatic monomer is predicted by means of FTIR measurements and said prediction is subsequently used to alter at least one process parameter.

Abstract: Process for controlling the (co)polymerisation of olefins in a continuous polymerisation reactor wherein the olefin (co)polymerisation is performed in an industrial plant reactor in the presence of a polymerisation catalyst characterised in that at least one operating parameter of the plant is controlled by means of a measurement of the chain branching level (CBL) of the produced polymer.

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 method of manufacturing a polymer composition that includes initiating a polymerization reaction at an initial set of polymerization parameters, determining a distribution of the at least one property of an intermediate polymer composition, and adjusting the initial set of polymerization parameters based on the distribution of the at least one property to obtain a desired distribution of the at least one property in the polymer composition. The method is suitable for use in blending and trimming operations as well as in polymerization processes.

Abstract: A method is disclosed for preparing broad or bimodal molecular weight distribution polyolefins having a targeted property, such as, flow index, melt flow ratio, or weight fractions of higher or lower molecular weight components. The method uses a bimetallic catalyst containing a metallocene component and a non-metallocene component, and the activities of the metallocene and non-metallocene portions are controlled by adjusting the ratio of organoaluminum and modified methylaluminoxane cocatalyst. The method allows for monitoring and adjustment of polyolefin properties on a real-time basis, as the polyolefin is forming.

Abstract: Processes, methods and apparatus relating to olefin polymerization include the use of Raman spectrometry to monitor the concentration of reactants, products or other chemical components. One or more polymerizaton conditions are adjusted in response to those monitored concentrations. The present processes, methods and apparatus are applicable with slurry olefin polymerization process, even though such slurry processes contain solid particles were are known to interfere with Raman spectrometry. Furthermore, the present processes, methods and apparatus are applicable where there is some degree of overlap between Raman spectral peaks. Methods of monitoring and controlling olefin polymerization processes, reactants and other components use Raman spectrometry.

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: Methods for controlling the temperature of an olefin polymerization reactor (e.g., a polyethylene reactor) system are disclosed herein. The olefin polymerization reactor system includes a polymerization reactor and a cooling jacket in thermal contact with the reactor. An aqueous froth is present in the jacket, and the pressure therein is maintained below atmospheric pressure. Control of the pressure in the jacket controls the boiling temperature of the jacket fluid, and thus, controls the rate of heat transfer from the reactor to the fluid in the jacket. This provides an efficient and simple means for controlling the reactor temperature.

Abstract: Noninvasive process for inline and/or online determination of polymer deposited from (meth)acrylic acid and/or (meth)acrylic esters by means of sound velocity measurements, measurements of the absorption coefficients in the infrared, near infrared, ultraviolet and/or visible region of the spectrum of electromagnetic radiation, or Raman spectroscopy, which allows precise control of the process parameters to be carried out during the thermal purification.

Abstract: Processes, methods and apparatus relating to olefin polymerization include the use of Raman spectrometry to monitor the concentration of reactants, products or other chemical components. One or more polymerizaton conditions are adjusted in response to those monitored concentrations. The present processes, methods and apparatus are applicable with slurry olefin polymerization process, even though such slurry processes contain solid particles were are known to interfere with Raman spectrometry. Furthermore, the present processes, methods and apparatus are applicable where there is some degree of overlap between Raman spectral peaks. Methods of monitoring and controlling olefin polymerization processes, reactants and other components use Raman spectrometry.

Abstract: A process for producing high density polyethylene (HDPE) or linear low density polyethylene (LLDPE) in gas phase reactors, isolated or combined, using chromium or Ziegler-Natta catalysts, provided with on-line control of certain process variables as well as physical properties of the produced resin is described. Such process comprises the use of models for the inference of the physical properties and of the process variables that are not continuously measured as well as models which are relevant for the control of said properties and of the operating conditions of the process. The control of the process variables provides further the maximization of the production rate and of the catalyst productivity in the polymerization reaction.

Abstract: The invention concerns a method for making polyamide. More particularly, the invention concerns a method for making polyamides derived from the reaction between a diacid and a diamine. It concerns a method for making a polyamide derived from the reaction of at least a diacid with at least a polyamide comprising the following steps: preparing a first mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 0.8 and 0.995, preferably ranging between 0.95 and 0.99 in a first reactor (5); preparing a second mixture of diacid and diamine with a diacid/diamine molar ratio ranging between 1.005 and 1.2, preferably between 1.01 and 1.05, in a second reactor (4); introducing in melted form a first flow of the first mixture and a second flow of the second mixture in a stirred polymer reactor (7); drawing, preferably, continuously, from said reactor a flow of polyamide prepolymer; feeding said polyamide flow into a finishing step to obtain the desired degree of polymerisation.

Abstract: A method for preparation of block copolymeric nanoparticles is disclosed. The method is a single-step preparation in which block copolymeric nanoparticles are produced directly from a solution of crosslinkable block copolymer in a carrier medium. The block copolymeric nanoparticles thus formed have at least one crosslinked polymeric phase.

Abstract: The present invention is a method for predicting polymer latex properties for an emulsion polymer latex based on statistical relationships between the polymer latex properties and process parameters for the emulsion polymerization process.

Abstract: A method for determining the endpoint of an interfacial reaction between a dihydroxy compound and a carbonyl halide comprises determining the characteristic end point of the reaction from a characteristic pH trace over time or ratio between caustic and carbonyl halide trace over time for the reaction; obtaining a pH trace over time or a ratio between caustic and carbonyl halide trace over time during the reaction to be monitored; and identifying the end point of the monitored reaction when the obtained pH or ratio trace resembles the end point determined from the characteristic pH or ratio trace.

Abstract: A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10−8 to 1×10−6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.

Abstract: A method of determining the quality of polymerization catalysts comprises

Abstract: A process for olefin polymerization in a reaction vessel, said process comprising polymerizing at least one &agr;-olefin in a polymerization stage employing a catalyst feed comprising 1) a first catalyst composition having at least two active catalytic sites capable of producing a first set of polymer components; 2) a second catalyst composition having at least two active catalytic sites capable of giving essentially the same set of polymer components as produced by the catalyst in feed (1) under the same polymerization conditions but these components in a different ratio to those produced by the catalyst composition of feed (1); wherein the amounts of catalyst compositions (1 and 2) fed into the reaction vessel are independently controlled.

Abstract: A method for monitoring and improving the performance of a chemical manufacturing process by monitoring transients associated with the operation of process equipment located dowstream of upstream equipment is disclosed. Transients on signals such as the motor current to downstream powder feeding equipment provide early indications of changes in chemical process performance which can then be corrected by altering chemical manufacturing process conditions.

Abstract: The invention relates to a method for the production of copolymer based on ethylene by continuous copolymerization of ethylene and comonomer in a reactor in the presence of a catalyst. In this method, in a first step of the copolymerization, a mixture comprising ethylene and comonomer of such a composition that a copolymer-containing coating deposits in the reactor is metered into the reactor and/or generated in the reactor, and, in a second step, the concentration of the comonomer in the metered-in mixture and/or in the mixture generated in the reactor is reduced sufficiently and/or the concentration of the ethylene in the metered-in mixture and/or in the mixture generated in the reactor is increased sufficiently that the coating is removed from the reactor either partially or completely. The method has the advantage that the production of copolymer does not have to be interrupted during cleaning of the reactor.

Abstract: The present application relates to a process for the continuous polymerization of isobutene while maintaining at a constant desired value a property P (viscosity or average molecular mass) of the polymer produced. The polymerization is conducted in a reactor comprising a boiling liquid reaction phase which contains the monomer and the polymer being formed, in equilibrium with a gas phase on top of the said liquid phase, by continuous introduction into the reactor of a catalyst and of a C4 hydrocarbon feed mixture comprising the monomer, and by continuous withdrawal from the reactor of the liquid reaction phase, which is subsequently subjected continuously to at least one purification step which is intended to isolate the polyisobutene produced.

Abstract: Isobutene polymerization process wherein a property P (viscosity or average molecular weight) of the polyisobutene product is maintained constant. The polymerization is conducted continuously in a reactor comprising a boiling liquid reaction phase in equilibrium with a gas phase, by continuous introduction into the reactor of a catalyst and of a C4 hydrocarbon feed mixture comprising the monomer, and by continuous withdrawal from the reactor of the liquid reaction phase. The process comprises the determination of a target value V of the partial pressure, PiC4, of the isobutene in the reactor gas phase corresponding to the desired value of the property P, by virtue of an empirical relationship established beforehand between the property P of the polyisobutene product and PiC4.

Abstract: A method of on-line monitoring and control of monomer conversion in emulsion polymerization includes continuously balancing, as from an initialization time, the heat QIN, introduced into the reactor, the reaction enthalpy QRE introduced via the monomer feed, and the heat which has been removed from the reactor QOUT, and calculating an amount of heat which has not been removed QAD which would lead to an increase in the internal temperature and the internal pressure of the reactor in the event of a spontaneous adiabatic reaction. A check is carried out as to whether the potential adiabatic temperatures and pressures always lie below prescribed upper limits. If the upper limits are exceeded, the monomer feed to the reactor is throttled back or interrupted.

Abstract: Method of olefin polymerization in a reactor, such as a slurry loop olefin polymerization reactor, is provided. The method includes conducting in-situ, real time spectroscopic analysis of one or more reactor constituents. The reactor constituents analyzed may be present in the reactor in either the liquid phase or the solid phase, or both. In response to the measured in-situ values, one or more reactor constituents may be metered into the reactor.

Abstract: Method of olefin polymerization in a reactor, such as a slurry loop olefin polymerization reactor, is provided. The method includes conducting in-situ, real time spectroscopic analysis of one or more reactor constituents. The reactor constituents analyzed may be present in the reactor in either the liquid phase or the solid phase, or both. In response to the measured in-situ values, one or more reactor constituents may be metered into the reactor.

Abstract: Bimodal resin products are produced in a single reactor by using two bicomponent catalyst compositions, each having a high molecular weight and a low molecular weight component, in different ratios. The HMW/LMW split of the final resin product is controlled accurately by controlling the ratio of the feed of the two bicomponent catalyst compositions. Bimodal or polymodal effects are also achieved for properties or characteristics other than molecular weight. More complex results can be achieved with more than two components. The invention is applicable to a wide variety of polymer products, particularly polyolefins and polyethylene.

Abstract: A method for controlling the production of formaldehyde resin compositions in which formaldehyde takes part in a reaction with one or a combination of co resin forming material (of the type phenol, urea, melamine) the method includes monitoring at least one of the formation of the reaction mixture and the course of the reaction by near-infrared (NIR) spectroscopy and adjusting the course of the reaction (when necessary) in accordance with the results of the spectroscopy to obtain optimum conditions for the reaction.

Abstract: Agglomerates 20 in a mixed phase container 1 are detected by measuring strain in a detecting rod 50 disposed in the mixed phase container 1 in which a mixed phase of gas and powders is formed. The detecting rod 50 is disposed at an insertion angle &thgr; in the range from 20 degrees to 70 degrees with relation to the flow of gas and powders.

Abstract: A protecting tube 51 is disposed inside the mixed phase container 1 with one end fixed to the inside of the mixed phase container 1 and the other end projecting freely into the mixed phase container 1. A detecting rod 60 is inserted into the free end of said protecting tube 51 and fixed to the protecting tube 51 with a part of the detecting rod 60. Magnets 61 are mounted in a uniform magnetic flux on the free end of the detecting rod 60 and is movable about a point F1 of the detecting rod 60 as a fulcrum. Agglomerates 20 in the mixed phase container 1 are detected by measuring magnetic flux fluctuations produced by movement of the magnets 61.

Abstract: A fluidized bed olefin polymerization process is operated in the turbulent regime while utilizing greater than 17.5% liquid in the recycle fluid to remove the heat of reaction. The ratio of fluidized bed density to settled bed density may, contrary to prior art predelictions, be maintained at lower than 0.59.

Abstract: Agglomerates 20 in a mixed phase container 1 are detected by measuring strain in a detecting rod 50 disposed in the mixed phase container 1 in which a mixed phase of gas and powders is formed. The detecting rod 50 is disposed at an insertion angle &thgr; in the range from 20 degrees to 70 degrees with relation to the flow of gas and powders.

Abstract: This invention relates to encoding methods using up-converting phosphors for high-throughput screening of catalysts. In particular, the invention relates to polymerization catalysts. In one embodiment of the invention, a monomer is combined with at least one labeled catalyst particle. The labeled catalyst particle comprises an up-converting phosphor label and a catalyst. The up-converting phosphor label identifies a particular catalyst. The monomer is polymerized to form a polymer bead surrounding the labeled catalyst particle. According to the invention, it is possible to combine two or more labeled catalyst particles in a commercially relevant large scale reactor to obtain direct comparison of different catalysts, and to avoid reactor effects that may occur when performed on the microscale. After the reaction, the resulting polymer beads are sorted, based on their size and/or phosphor labels.

Abstract: In a polymerization reaction, an upset is anticipated and inhibited by monitoring at least one reaction condition and comparing it to the desired value or normal range for the condition as projected by a computer model for the variable or variables of the process. In a preferred variation, the process not only continuously adjusts the set point or range for an upset-significant variable such as temperature, but also utilizes the rate of change of such a variable as a harbinger of an upset.

Abstract: A method for manufacturing polycarbonate by melt-polycondensing bisphenol and carbonic acid diester uses as catalyst an alkali metal compound and/or alkaline earth metal compound (a). The catalyst is added to the bisphenol prior to the melt polycondensation, in an effective amount, i.e., the amount of alkali metal compound and/or alkaline earth metal compound (a) that acts effectively as a catalyst, is contained in said bisphenol, and is controlled to have the same catalytic activity as 1×10−8 to 1×10−6 mole of bisphenol disodium salt per mole of pure bisphenol A. The method conducts the reaction efficiently from the initial stage in a stable manner to obtain polycarbonate with good color, good heat stability and color stability during molding and the like.

Abstract: A process for starting up a reaction for the polymerization of an olefin in the gas phase carried out using a catalyst based on chromium oxide in a fluidized bed reactor through which moves a reaction gas mixture containing the olefin, wherein in the start-up of the reaction, the olefin is introduced into the reactor until the desired production of polymer is reached by means of a two-stage process, during the first stage of which the introduction of the olefin is carried out so as to maintain a constant partial pressure of olefin in the reactor and during the second stage, the introduction of olefin is regulated at a constant flow rate.

Abstract: There is provided a bulk handling method for maintaining granular material in a free-flowing state in a vessel during storing, transporting, or while in an idle mode in a fluidized-bed reactor or purger.

Abstract: A falling film of water is applied around the periphery of a fluid bed olefin polymerization reactor to cool the wall and reduce the temperature in the fluid bed near the inside surface of the wall. Cooling has the effect of reducing static in the reactor, which in turn ameliorates a sheeting problem and can enhance production by facilitating control of the relation of the reactor temperature and the dew point of recycled gas. The process may be used concurrently with a gas cooling and condensing recycle system wherein at least some of the condensed recycle gas is injected in the vicinity of the internal wall surface.

Abstract: An improvement in a method for evaluating the efficiency of polymerization inhibitors is disclosed, wherein the improvement comprises: A) producing dissolved polymer in a solution comprising monomer and at least one inhibitor by means of any test known in the art to be useful for evaluating polymerization inhibitors, B) collecting the polymer-containing solution, C) measuring the degree of polymerization of the monomer in the collected solution, and D) re-subjecting the polymer-containing solution to the test conditions of A).

Abstract: The present invention is directed to a method for polymerizing olefins in a multi-stage polymerization apparatus including a gas-phase polymerization reactor in a subsequent stage. By use of the present method, the composition of gas in the gas-phase reactor is easily adjusted, and moreover, a polymer having an intended composition is produced in a consistent manner. In one aspect, the method for polymerizing olefins is performed in successive, multiple stages by use of a plurality of polymerization reactors disposed in series which include at least one gas-phase polymerization reactor after a first reactor, wherein a multi-component gas is removed from a gas-phase reactor and pressurized and/or cooled to thereby liquefy a portion of the gas; at least a portion of gas is discharged; and the remaining gas and the liquid are returned to the gas-phase reactor.

Abstract: In gas phase fluid bed polymerization processes, operation can be achieved over wider ranges of fluidizing gas velocities without incurring undue energy costs by adjusting the pressure drop through the grid below the bed to provide a ratio of pressure drop through the grid to pressure drop through the grid and bed above about 0.15:1. The range of fluidizing gas velocities can enhance the practicality of operating the processes over varying bed heights while reducing the risk of forming deposits of polymer. The processes of the invention are particularly useful to accommodate start-ups, catalyst transitions and shutdowns.

Abstract: A process, particularly a gas phase fluidised bed process, for the production of polymers avoids formation of sheets or chunks within the reactor, without the need to use antistatic agents, which can reduce the activity of the catalyst or alter the characteristics of the yielded product. According to the invention, a device generates a corona discharge in the polymerisation reactor during the polymerisation process; an AC voltage difference is applied between the elements which constitute the discharging pair of the device.