Abstract: The present invention is a method for the production of a water absorbent resin, which comprises preparing a monomer component possessing an ability to form a cross-linked structure and convert itself into a hydrated gel polymer during the course of aqueous solution polymerization, possessing an acid group-containing monomer content of at least 50 mol %, and having 10 to 50 mol % of said acid group-containing monomer neutralized and subjecting said monomer component to aqueous solution polymerization within a reaction vessel having a plurality of rotary shafts each fitted with stirring blades.

Abstract: A process for (co)polymerizing alpha-olefins in the gas phase in a fluidized bed or mechanically stirred bed reactor using a Ziegler-Natta type catalyst or a heat activated chromium oxide/refractory oxide catalyst wherein the (co)polymerization is carried out in the presence of 0.005 to 0.2 weight %, based on the weight of the (co)polymer bed, of an inert pulverulent inorganic substance (e.g. silica) having a mean particle diameter between 0.5 and 20 microns. The process is capable of being operated at temperatures closer to the softening point of the produced polyolefin than in the absence of the pulverulent solid.

Abstract: Synthetic elastomers are typically made commercially by employing emulsion polymerization or solution polymerization techniques. In such solution polymerization techniques, it is desirable to operate at the highest solids content which is practical. As a general rule, it is not practical to prepare such rubbers by solution polymerization at solids contents of higher than about 20 percent. However, the subject invention reveals a technique for preparing such rubbers by high solids solution polymerization at extremely high solids contents. This technique offers substantial advantages associated with eliminating large quantities of organic solvents.

Abstract: Paste-forming vinyl chloride polymers are prepared using an emulsifier system of:(a) an alkali metal or ammonium salt of a fatty acid, alkylsulfonic acid, alkylarylsulfonic acid or a sulfosuccinic acid ester in quantities of 0.2 to 3.0 by weight with respect to the quantity of monomers,(b) a straight chain or branched C.sub.12 -C.sub.20 alkanol in quantities of 50 to 200% by weight with respect to the amount of surface active agent (a) used,(c) water and optionally,(d) a monomer-soluble catalyst. The emulsifier system is homogenized by means of homogenizing apparatus, and, subsequently is mixed with the monomer. Polymerization ensues. Pastes based on this polymer exhibit low viscosities, a near Newtonian flow behavior and good storage stability.

Abstract: A process and apparatus are provided for producing polymerized plugs in which the polymerization starting materials are passed through heated reaction tubes by gravity feed. The polymerized rods so produced are cut into plugs and packaged for use. In an alternative embodiment, the polymerization starting materials are first encased within flexible sleeves, and the flexible sleeves are then passed through the heated tubes by gravity feed to form polymerized rods. Apparatus for performing the process includes at least one tube having an inlet opening and an outlet opening, the outlet opening being at a lower elevation than the inlet opening to provide for gravity feed through the tube, and structure to heat the tube. A cutting device cuts the polymerized rods into plugs as they exit the outlet opening.

Abstract: A process for producing a styrene resin by continuous bulk polymerization using a polymerization apparatus comprising a circulating line (I) for initial-stage polymerization including at least one tubular reactor having fixedly set therein a plurality of mixing elements having no moving parts and a main-polymerization line (II) following the circulating line (I) and including at least one tubular reactor having fixedly set therein a plurality of mixing elements having no moving parts; characterized in that while a polmerization solution containing a styrene monomer (A), an organic solvent (B) and an organic peroxide (C) whose half life reaches 10 hours at a temperature of 75.degree. to 130.degree. C. is polymerized in the initial stage while it is circulated through the circulating line (I), and at the same time, a minor part or a major part of the initial-stage polymerization solution is introduced continuously into the main-polymerization line (II) and polymerized.

Abstract: A method of carrying out a continuous aqueous emulsion copolymerization using a single continuously stirred tank reactor to reduce the particle size distribution and the presence of over-sized particles comprises, slowly supplying to a reactor the materials used in the copolymerization, including the monomers which are copolymerized, while maintaining conditions causing copolymerization to proceed until the reactor is filled. The supply is continued while maintaining those conditions until the total supply is in the range of from about 1.5 to about 5 reactor volumes. The excess material in the reactor is removed therefrom and collected in one or more separate vessels, and the product of the copolymerization is then combined and mixed to form a uniform product. The composition copolymerized can be changed during the copolymerization. The emulsion copolymer product is particularly useful in latex paints where it improves the gloss and scrub resistance of the paint.

Abstract: A process for producing a styrene/(meth)acrylic acid copolymer continuously by a bulk or solution polymerization technique, wherein the polymerization is carried out continuously by using at least two polymerization vessels arranged in series and equipped with a mixing device while (meth)acrylic acid is continuously fed into each of the polymerization vessels.

Abstract: The process and the system are used for carrying out the quench-cooled, vapor-phase polymerization of olefin monomer in a horizontally disposed reactor vessel which comprises contacting olefin monomer, or a mixture of olefin monomers, with a polymerization catalyst system in the presence of hydrogen in the reactor vessel to form a polymer product. The improvement comprises introducing a titanium-containing catalyst component of the catalyst system into the top side of the reactor vessel at a point adjacent to the upstream end of the reactor vessel and introducing a cocatalyst plus modifer component of the catalyst system into the top side of the reactor vessel at a distance, downstream of the point of introduction of the titanium-containing catalyst component, which is equal to 25% of the inside diameter of the reactor vessel.

Abstract: A vertical autoclave for carrying out operations involving a medium having a liquid phase and/or a solid phase, comprising:(a) a concave autoclave bottom;(b) a shaft along a vertical axis of said autoclave, said shaft passing through said bottom of said autoclave; and(c) stirrer means for driving said medium with a centripetal motion about said concave autoclave bottom.

Abstract: The invention relates to a process for the preparation of a thermoplastic polymer on the basis of an alkenyl aromatic monomer, an unsaturated dicarboxylic anhydride, and, optionally, a rubber, characterized in that the monomers and/or solution thereof are/is reacted in at least two reaction zones that are in open connection with each other at the top and at the bottom, the reaction mixture being circulated through the reaction zones by means of a mixing device and/or a conveying device.Using the process, a homogeneous product of constant composition is obtained.

Abstract: A polymerization process is provided for producing a terminally functional polymer which comprises introducing a monomer charge, a Lewis acid and an organic peroxy compound into a suitable reaction vessel and polymerizing the monomer charge at a temperature of from about 0.degree. to about -80.degree. C. to form the terminally functional polymer, wherein the monomer charge comprises isobutylene and the organic peroxy compound is charge in an amount of from about 10.sup.-4 to about 10.sup.-1 moles per mole of the isobutylene. In a preferred embodiment, the monomer charge additionally comprises vinylidene aromatic or diolefin monomers. The invention also provides a novel catalyst system comprising an organic peroxy compound and a Lewis acid for the polymerization of isobutylene or monomer mixtures containing isobutylene.

Abstract: Process for gas phase polymerization of olefins using a highly active catalyst in a fluidized bed reactor (1), comprising a recator body (2) partially occupied by the fluidized bed and surmounted by a disengagement chamber (3). The gas mixture withdrawn from the disengagement chamber (3) is fed to a dust separator (6) e.g. a clycone, to separate the fine particles entrained by the gas. The gas is cooled, compressed and recycled to the base of the reactor. The particles are withdrawn from the dust separator (6) by a mixing device (8) which mixes the particles with a carrier gas. The carrier gas and particles are recycled to the reactor where they are introduced into the reactor body (2) through an opening in the side wall thereof at a position above the fluidized bed, but below the disengagement chamber (3). The velocity of the particles introduced into the reactor is insufficient to cause them to be blown directly into the bed.

Abstract: A fluidized bed reactor and operating process is disclosed, the reactor including distributor plate means to provide distribution of fluid passing upwardly into a fluidized bed; a mixing chamber positioned below the distributor plate means; fluid entry means, preferably at the base of the reactor, for the passage of fluid into the reactor; flow deflector means associated with the entry means for providing at least an upwardly fluid flow path and an outward fluid flow path along the wall of the mixing chamber to inhibit the accumulation of solids and liquid in the mixing chamber.

Abstract: A process for reducing sheeting during production of polyolefins by polymerization of alpha-olefins utilizing titanium based polymerization catalysts wherein the static electric charges in the reactor at the side of possible sheet formation are maintained below static voltage levels which would otherwise cause sheet formation.

Abstract: By a process for suspension polymerization, which comprises steps of:supplying a slurry comprising droplets of a monomer liquid having a substantially uniform size dispersed in an aqueous dispersion medium to a tower type reactor in which said medium forms a downflow, andsuspension polymerizing the monomer with avoiding merging or splitting of the droplets in a fluidized bed which is formed by the downflow of said medium and buoyancy of the monomer liquid droplets, whereinthe specific gravity of said medium is made larger than that of a polymer particle to be produced by the addition of a water soluble inorganic salt to said medium, anda polycarboxylic acid type anionic polymeric surfactant is used as a suspension stabilizer for the monomer liquid droplets,polymer particles having a substantially uniform size are produced with high polymerization conversion.

Abstract: A process for preparing polymers and copolymers based on vinyl chloride by mass polymerization of a monomer composition based on vinyl chloride, comprising carrying out at least part of the polymerization reaction in a polymerization zone defined by an essentially spherical wall by effecting in the said polymerization zone a controlled and regulated circulation of the polymerization reaction mixture by means of a rotated blade-type turbine assembly, where the said blades pass by in the vicinity of the said wall over 10% to 60% of its surface, the reaction mixture being caused by the centrifugal force of said rotated blade-type turbine assembly to perform an at least partially ascending movement over at least part of the spherical wall and falling back, essentially under the action of gravity in the central part of the spherical polymerization zone, thus ensuring intensive mixing without dead space.

Abstract: A polyester having a high quality is produced by stirring its polycondensation reaction mixture in such a way that the stirring rate is reduced continuously in a stepwise manner corresponding to an increase in the melt viscosity as the reaction proceeds so that the stirring load is substantially constant after the viscosity of the reaction system has reached an arbitary value between 20 and 800 P until the completion of the reaction.

Abstract: The polymerization of fluoromonomers can be accomplished without fouling by using gaseous monomers in the presence of at least one nonvolatile initiator and by recycling the initiator-free polymerizer gases through an external cooler.

Abstract: Control of an anionic polymerization is obtained by monitoring an indicator of molecular weight of the polymer in the polymerizing mixture, measuring the molecular weight of the polymer produced therein and using this information to control the rate at which polymerization initiator is added to the polymerizing mixture in a continuous stirred tank reactor.

Abstract: Disclosed is a method of making a polymer containing more than 50 to about 95 mole percent, preferably 65 to 80 mole percent, of units derived from maleic anhydride and the balance units derived from at least one 1-alkene. The method comprises mixing the maleic anhydride and 1-alkenes selected in the presence of a thermally decomposable initiator and, optionally, in the presence of a solvent at a temperature ranging between 145.degree. C. to 200.degree. C., in such a manner that throughout the process, the ratio of maleic anhydride to 1-alkenes is more than 50:50 to about 95:5, most preferably between 65:35 to 80:20, to form a reaction mixture and thereafter maintaining the reaction mixture at from 145.degree. C. to 200.degree. C. until a polymer containing more than 50 mole percent of maleic anhydride is obtained.

Abstract: The present invention relates to a process and an apparatus for the continuous production of polymers and copolymers of water-soluble monomers particularly arcylic acid and/or methacrylic acid, optionally with additional comonomers, by the polymerization of an aqueous monomer solution that is introduced into the trough that is formed by an endless conveyor belt. The trough-like shape of the conveyor belt changes continuously into an extended flat profile during the polymerization process; starting from the side edges and working towards the center of the trough formed by the conveyor belt, the resulting polymer gel strand is released continuously during the transition of the curved trough-like shape of the conveyor belt into the extended, flat form.

Abstract: The present invention relates to a gas fluidized bed process for the production of copolymers having a density between 0.900 and 0.935, which process comprises copolymerization of (a) ethylene, (b) propylene and/or 1-butene, and (c) alpha-olefins comprising from 5 to 8 carbon atoms in the gaseous state, in admixture with an inert gas and optionally with hydrogen, in the presence of a catalytic system comprising a cocatalyst consisting of at least 1 organo-metallic compound of a metal of groups II and III of the Periodic Table of Elements and a special solid catalyst.

Abstract: The present invention provides a process for producing vinyl chloride resin in suspension polymerization of vinyl chloride monomer by the use of a polymerization reactor equipped with a reflux condenser using an improved brumagine-type impeller equipped with auxiliary blade/s, and polymerization is started in a range of 0.8 to 1.0 of the water/monomer ratio, polymerization temperature is raised to 3.degree. to 10.degree. C. at polymer conversion being not more than 50 weight percent, with water being added in the course of polymerization not more than making up for the volumetrical contraction resulting from the progress of polymerization so that upon completion of polymerization the water/monomer ratio is controlled in a range of 1.0 to 1.4. The polyvinyl chloride resin obtained by the present process is superior in quality such as high bulk density and little fish eye with high productivity.

Abstract: Inherently tacky, elastomeric, solvent-dispersible, solvent insoluble polymeric microspheres prepared using non-ionic suspension stabilizers and non-ionic emulsifiers.

Abstract: There is provided an improvement in a method for terminating a gas phase olefin polymerization reaction with a kill gas such as carbon monoxide or carbon dioxide. The improvement involves the use of a carrier gas to increase the rate of penetration of kill gas into the reaction medium. The improved method is particularly adaptable to a fluid bed reactor system.

Abstract: A process for preparing vinyl chloride homopolymer or copolymer latexes, comprising carrying out the polymerization of a monomer composition in a reaction medium in emulsion or in microsuspension and continuously condensing a vapor fraction of said monomer composition and continuously refluxing said condensed vapor fraction into said reaction medium, degassing the resultant polymer, and carrying out the polymerization under agitation by means of a paddle agitator with a rotating shaft having at least one paddle and at least one deflector with the speed gredient between said at least one paddle and said at least one deflector being between 5 and 50 s.sup.-1 ; the peripheral rotational speed of the agitator is maintained in the range of about 1.1 to 2.1 meters/second for about 50% to 100% of the duration of the polymerization period preceding the beginning of reflux (P.sub.1) and the period which separates the end of reflux from the beginning of degassing (P.sub.3), and at a speed in the range of about 0.

Abstract: The time taken for a run of suspension polymerization of vinyl chloride monomer can be remarkably decreased without affecting the quality of the resin product when the temperature of the polymerization mixture under polymerization is increased continuously or step-wise during the period in which the conversion of the monomer to polymer is 10% or larger in such a manner that the average degree of polymerization of the polymer taken at an intermediate stage by sampling is always in the range from 90% to 110% of that of the finally obtained polyvinyl chloride resin product.

Abstract: A method and apparatus for continuously manufacturing water absorbing resin. A mixed monomer solution is stored in a storage vessel and a polymerization initiator stored in an initiator storage vessel. The monomer solution is fed by gravity or otherwise through a conduit to a lower position (below the liquid surface) of a reaction chamber of a reaction vessel at a rate of, for example, 4 gallons per minute. Simultaneously, the polymerization initiator is fed at a rate of, for example, 0.2 gallons per minute by gravity or otherwise through a conduit to an opposite side of the reaction chamber, again at a lower portion (below a continuously maintained liquid level) to begin polymerization. The reaction product forms from an upper surface of the reactant mixture (mixed monomer solution plus initiator) and travels upwardly through a truncated frustoconical cone shaped upper portion of the reaction chamber as a solid resin.

Abstract: A method for producing homopolymers and copolymers from amido-sulfonic acid or salt containing monomers in the presence of high energy mechanical mixing utilizing a final stage polymerization temperature of from about 200.degree. F. to below the degradation temperature of the monomer. The process produces a solid homopolymer or copolymer which can be utilized as fluid loss agents.

Abstract: Process for the preparation of thermoplastic copolymers of .alpha.-methylstyrene and acrylonitrile by continuous bulk copolymerization ofA. 30 to 50 mol % of .alpha.-methylstyrene andB. 70 to 50 mol % of acrylonitrileat temperatures from 60.degree. to 120.degree. C. with average residence times of 4 to 12 hours in the presence of initiators which supply free radicals, carried out in at least two continuously operated mixed tank reactors, characterized in that 100 molar parts of a monomer mixture ofA.sub.0. 34 to 52 mol % of .alpha.-methylstyrene andB.sub.0. 66 to 48 mol % of acrylonitrileare fed continuously into the first tank reactor per unit time, and, with back-mixing, are copolymerized up to a conversion of 5 to 30 molar parts to give a copolymer of the compositionA.sub.1. 49 to 53 mol % of .alpha.-methylstyrene andB.sub.1. 51 to 47 mol % of acrylonitrile,and the mixture consisting of 70 to 95 molar parts of the monomers A and B and 5 to 30 molar parts of the copolymer of the composition A.sub.1 -B.sub.

Abstract: Copolymers of ethylene with vinyl esters are prepared in a continuously operated tubular polymerization system at high pressure and temperatures by feeding a mixture of ethylene, vinyl ester, initiator and, if appropriate, regulant into the polymerization system in the form of a mainstream at the inlet point thereof and at the same time through two or more secondary streams downstream of the inlet point, secondary streams (I) being metered in at points where the reaction temperature has just exceeded a maximum temperature due to the heat of polymerization and secondary streams (II) at points which, relative to the direction of flow of the ethylene, are upstream of the feed points of secondary streams (I) and upstream of the respective maximum temperature.

Abstract: A process for the continuous preparation of finely divided homopolymers and copolymers of ethene by catalytic polymerization in a circular tube reactor using a liquid alkane as reaction medium in which the ethene or ethene/comonomer mixture to be polymerized is present in dissolved form and the polymer formed is present in suspended form and running the reaction mixture as a cycle stream to which the feed materials are added by bleeding in and from which the polymer formed is withdrawn by bleeding out reaction mixture, comprising (a) maintaining the mean concentration C.sub.m of polymer in the cycle stream at a value within a certain range and (b) effecting the bleeding out of reaction mixture at a point of the cycle stream at which the concentration of polymer has a value which is lower than the mean concentration C.sub.m by a distinct and definite amount.

Abstract: A method for preparing a polymodal MWD ethylene-alpha olefin copolymer using at least two catalysts to initiate growth of polymer chains that attain different average molecular weights. The polymodal MWD ethylene copolymer comprises at least two different molecular weight modes each mode having a narrow MWD and at least one of two characteristics (1) an Mw/Mn of less than 2 and (2) Mz/Mw of less than 1.8.

Abstract: A process for the preparation of infusible, solvent-insoluble, solvent-dispersible, inherently tacky elastomeric polymeric microspheres without the use of a suspension stabilizer comprising the steps of: (a) charging to a reaction vessel: (1) at least one alkyl acrylate or methacrylate ester monomer; (2) at least one emulsifier at a concentration above its critical micelle concentration; and (3) an effective amount of at least one substantially water insoluble polymerization initiator; (b) agitating the reaction vessel charge prior to the initiation of the reaction sufficient to create a suitable monomer/water emulsion in the reaction vessel; and (c) maintaining the agitation for a time sufficient to allow substantially complete conversion of the monomer. This process forms elastomeric, solvet-dispersible, polymeric micropheres.

Abstract: Polymodal MWD ethylene copolymer comprising at least two modes of differing molecular weights. Each mode has at least one of M.sub.w /M.sub.n of less than 2.0, and a M.sub.z /M.sub.w of less than 1.8. The polymodal character of the copolymer is achieved by either (1) withdrawing polymer modes from the reactor from at least one takeoff port, and blending such modes with the reactor effluent, or (2) utilizing at least two catalyst species in the reaction to produce modes of differing molecular weights.

Abstract: Protection against molecular weight depression in the polymerization reaction producing polyisobutylene rubber or butyl rubber is achieved through addition of minor amounts of certain metal alkyls, particularly the lower alkyl aluminum compounds or lower alkyl aluminum hydrides which function as buffering, neutralizing or complexing agents against polymerization poisons and extraneous catalyst activators.

Abstract: Finely divided, gel-like crosslinked polymers are prepared by a continuous method in which a monomer mixture which contains, per 100 parts by weight of acrylic acid or methacrylic acid, from 50 to 100 mol % of which in each case are neutralized, acrylamide, methacrylamide or N-vinylpyrrolidone, from 0 to 30 parts by weight of other water-soluble monoethylenically unsaturated monomers and from 0 to 20 parts by weight of water-insoluble monoethylenically unsaturated monomers is copolymerized with from 0.01 to 5 parts by weight of a crosslinking agent, in 20-65% strength by weight aqueous solution in the presence of an initiator at from 45.degree. to 95.degree. C.

Abstract: The present invention provides a method for improving impulse destructive strength of an electrical insulating material which is characterized by employing, as the electrical insulating material, a random copolymer of a styrene series monomer and ethylene or a combination of ethylene and another ethylenic unsaturated monomer, or a composition in which the copolymer is blended with an ethylene series polymer, the copolymer being prepared by introducing, into a reaction system, the styrene series monomer selected from the group of styrene and single-ring substituted styrenes, ethylene or the combination of ethylene and the ethylenic unsaturated monomer and a polymerization initiator, the latter being introduced thereinto separately from at least the styrene series monomer, and subjecting these monomers to a high-pressure radical copolymerization under a polymerization pressure of 500 to 4,000 kg/cm.sup.2 at a polymerization temperature of 50.degree. to 400.degree. C.

Abstract: The present invention relates to a process for the polymerization of alpha-olefins in the gas phase in the presence of a Ziegler-Natta catalyst system consisting of a catalyst comprising atoms of halogen, magnesium and a transition metal, and cocatalysts based on an organometallic compound of a metal of Groups II or III of the Periodic Table of Elements, this catalyst system being previously converted into a prepolymer or a catalyst supported on a granular substance. This process is characterized in that the polymerization in the gas phase is carried out by contacting one or more alpha-olefins, on the one hand with the prepolymer or the supported catalyst system comprising an organometallic compound (a) which is only slightly volatile as cocatalyst, and on the other hand another cocatalyst consisting of an organometallic compound (b) which is relatively volatile, in such a way that the total quantity of cocatalyst employed is relatively small.

Abstract: A reactor for carrying out polymerizations in systems with high concentration of polymer is constituted by a cylindrical body having vertical axis with upper and lower heads; in correspondence of a generatrix of the cylinder an opening with vertical-axis is provided, which puts the interior of the cylinder in communication with the body of an extruder, it too with vertical axis, and solid with the reactor.

Abstract: An apparatus for producing a polyacetylene film by contacting acetylene gas with Ziegler-Natta catalyst to polymerize the acetylene gas in a vessel which comprises a catalyst introduction conduit to be introduced with the Ziegler-Natta catalyst provided at a cap provided at the top of the vessel and having an end opening disposed in the vicinity of the inner surface of the side wall of the vessel in such a manner that the conduit and the vessel are relatively moved in rotation, and a rotary transmission mechanism for driving to rotatably coat the catalyst flowed out from the end opening of the conduit on the inner surface of the bottom from the inner surface of the side wall of the vessel. Thus, the polyacetylene film can be produced in a uniform thickness and in a relatively large area by introducing the Ziegler-Natta catalyst of the suitable quantity, and the catalyst can be spread over the entire surface rapidly by the relative rotation between the conduit and the vessel.

Abstract: A less colored .alpha., .beta.-unsaturated carboxylic acid polymer having a relatively small molecular weigth and a sharp molecular weight distribution is produced by supplying an .alpha.,.beta.-unsaturated carboxylic acid monomer and a hydrogensulfite from one side of a reaction column and simultaneously supplying an oxygen-containing gas concurrently with the monomer to the reaction column. The polymer obtained is preferably used as a dispersant and an antiscaling agent.

Abstract: A process for the gas phase homopolymerization of vinyl chloride or the gas phase copolymerization of vinyl chloride with a monomer copolymerizable therewith, wherein when the breeding ratio first exceeds 3.5 after initiation of the polymerization, the feed rate of a seed polymer is adjusted so that the breeding ratio is maintained at a level of from 3.5 to 5.5.

Abstract: A polyvinyl chloride having high bulk density and enhanced plasticizer absorption is produced by suspension polymerization of vinyl chloride monomer and comonomers wherein the initial suspension of ingredients is generated such that the oil phase droplets formed in the suspension are compositionally equivalent with respect to initiator, and the level of suspending agent and agitation are chosen to substantially preclude agglomeration of resin particles throughout the reaction, thereby producing resin wherein the resin grain size distribution results directly from the oil phase droplet distribution created at or near the start of the reaction. The process is conducted under conditions so that the polymerization is commenced before the final distribution is established. In this manner, seed particles of resin are produced from the vinyl monomer prior to establishing the final particle distribution.

Abstract: A polyvinyl chloride having high bulk density and enhanced plasticizer absorption is produced by suspension polymerization of vinyl chloride monomer and comonomers wherein the initial suspension of ingredients is generated such that the oil phase droplets formed in the suspension are compositionally equivalent with respect to initiator, and the level of suspending agent and agitation are chosen to substantially preclude agglomeration of resin particles throughout the reaction, thereby producing resin wherein the resin grain size distribution results directly from the oil phase droplet distribution created at or near the start of the reaction. The process is conducted under conditions so that the polymerization is commenced before the final distribution is established. In this manner, seed particles of resin are produced from the vinyl monomer prior to establishing the final particle distribution.

Abstract: Control of an anionic polymerization is obtained by monitoring an indicator of molecular weight of the polymer in the polymerizing mixture, measuring the molecular weight of the polymer produced therein and using this information to control the rate at which polymerization initiator is added to the polymerizing mixture in a continuous stirred tank reactor.

Abstract: The present invention relates to a process for polymerizing or copolymerizing alpha-olefins comprising, on the one hand, a prepolymerization stage by contacting one or more alpha-olefins with a Ziegler catalyst system consisting of a solid catalyst containing essentially atoms of halogen, magnesium and transition metal, and a co-catalyst consisting of an organomatellic compound, and, on the other hand, a polymerization or copolymerization stage in a gas phase process by means of a fluidized bed, by contacting one or more alpha-olefins with the prepolymer produced in the first stage, process characterized in that the alpha-olefin prepolymer and polymer or copolymer are in the form of a powder consisting of particles having specific values for the transition metal content and the mean diameter by mass, and characterized in that the particle size distribution of the prepolymer is narrow and easily controlled.

Abstract: The invention relates to a continuous process for the manufacture of butyl rubber in which the monomers are polymerized using a halogenated polymerization medium in a self-cleaning screw extruder at a constant pressure under boiling plug-flow conditions by means of a modified aluminium halide catalyst which operates at high temperature (relative to prior art very low temperatures of e.g. -100.degree. C.). In contrast to prior art slurry processes, the polymerization mixture forms a sticky, highly viscous mass which is conveyed by screw action to the extruder outlet as polymerization proceeds. The butyl rubber product is separated at a high concentration from vapors of unreacted monomers and polymerization medium which are recycled.

Abstract: A method for producing by suspension polymerization a copolymer comprising a vinyl cyanide compound and an aromatic vinyl compound having excellent transparency, and uniform composition, and a content of the polymerized residue of vinyl cyanide compound in the range of from 50 to 85% by weight comprising the steps of: (a) carrying out initial charging of the total quantity of the vinyl cyanide compound and a partial quantity of the aromatic vinyl compound at a compositional ratio, wherein the content of the vinyl cyanide compound in the resulting copolymer attains an intended ratio within a range of from 50 to 85% by weight; (b) initiating the copolymerization reaction by adding a polymerization initiator having a decomposition half-life at 95.degree. C.