Abstract: A process for producing polymers in a gas phase reactor by continuously introducing a stream of monomer and gas into a polymerization zone while maintaining the temperature within the polymerization zone below the dew point temperature of at least one monomer present in said polymerization zone.

Abstract: A fluidized bed-type polymerization apparatus has an upper blowing equipment installed at a definite height in the fluidized bed area. Through the equipment, a part of the circulating gas and a part, or the whole, of the fresh feed material is blown, thereby to prevent the formation of lumps of polymer in the fluidized bed portion, owing to improved intermixing at the upper portion of the fluidized bed, as well as efficient heat-removal at that portion.

Abstract: The invention is directed toward polymerizing or copolymerizing alpha-olefins either alone or in combination with one or more other alpha-olefins in a gas phase reactor having a fluidized bed and a fluidizing medium such that the fluidizing medium entering the reactor comprises a gas and a liquid phase.

Abstract: The present invention relates to a gas phase fluidized bed reactor (1) comprising an upright tubular portion (2) having a fluidization grid (4) in the lower part thereof. According to the invention the upright tubular portion (4) is provided with an external conduit (13) which connects a lower orifice (14) which is above the fluidization grid (4) and an upper orifice (15) which is a height above the lower orifice (14). The invention also relates to a gas phase polymerization process carried out in the reactor.

Abstract: Olefin polymerization is conducted with a Ziegler-Natta catalyst in which unreacted monomer is recycled to the reactor. The recycle line contains a supported nickel or nickel oxide to purify the unreacted monomer before its return to the reactor, and results in improved catalyst activity and more control over physical properties of the product.

Abstract: A process for preparing olefinic polymers by metallocene catalyzed olefin polymerisation in which at least one volatile catalyst kill agent is introduced. A non-volatile catalyst kill agent may also be used in conjunction with the volatile catalyst kill agent. Water may be used as the volatile agent and compounds containing a terminal hydroxy group, oxygen, nitrogen or sulfur may constitute the non-volatile agent. Purified monomer is recycled to the reactor.

Abstract: The invention is directed toward polymerizing alpha-olefins either alone or in combination with one or more other alpha-olefins utilizing a bulky ligand transition metal catalyst in a gas phase fluidized bed polymerization reactor operating in condensed mode.

Abstract: A method of recovering and recycling monomers from a gas phase olefins polymerization reactor through the use of the monomer feed stream. A high pressure monomer source is reduced in pressure so as to reduce the temperature of the monomer source. The monomer source is then used to cool and condense monomers contained in various vent gas streams. The condensed monomers are then separated from the gas stream and recycled back to the reactor.

Abstract: A process for polymerizing olefins in a gas-phase fluidized-bed reactor comprising a reactor body (1), optionally surmounted by a disengagement chamber (2), in which fine particles entrained by the gas mixture leaving the top of the reactor are separated from the gas and recycled to the upper portion of the reactor body. Polymer is withdrawn from the reactor body (1) via at least two polymer outlets, at least one of which (15) is in the lower portion of the reactor body (1) and at least one of which (16) is in the upper portion of the reactor body at a position below the top of the fluidized bed. The invention includes apparatus for polymerizing olefins and the use of the apparatus.

Abstract: Unreacted monomer present in an ethylene/C.sub.3 -C.sub.8 alpha-olefin copolymer product produced in a catalyzed fluid bed polymerization process is purged with a gaseous stream obtained by subjecting a portion of the gaseous effluent from the fluidized bed to a partial condensation, separating the liquid phase from the gaseous phase obtained and employing the gaseous phase as the gas to purge unreacted monomer from the copolymer product.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: The invention is directed toward polymerizing or copolymerizing alpha-olefins either alone or in combination with one or more other alpha-olefins in a gas phase reactor having a fluidized bed and a fluidizing medium such that the fluidizing medium entering the reactor comprises a gas and a liquid phase.

Abstract: A process for the preparation of a polycarbonate comprising reacting a diaryl carbonate with a bisphenol to produce a polycarbonate and a phenol, regenerating the diaryl carbonate by reacting the phenol byproduct with a carbonyl halide, and optionally recycling the hydrogen halide using a metal Redox captive halogen swing reactor system.

Abstract: In a polymerizing apparatus which comprises a polymerization vessel and a circulating line comprising a heat exchanger installed outside said polymerization vessel and a circulating pipeline extending from said polymerization vessel and returning to said polymerization vessel through said heat exchanger, the improvement comprising a strainer installed in the course of said circulating pipeline. Since polymer scale and a polymer in the form of blocks formed in the circulating line can be trapped, the circulating pipeline and tubes of the heat exchanger can be prevented from being blocked up. Further, since they can be prevented from mixing with a reaction mixture in the polymerization vessel, when the obtained polymer is worked into a molded item such as a sheet, fish eyes can be prevented from increasing. Therefore, a polymer can be produced efficiently with high productivity.

Abstract: There is disclosed a process for continuously and efficiently producing a styrenic polymer having a high degree of syndiotactic configuration which comprises effecting polymerization reaction by continuously introducing a styrenic monomer and a polymerization catalyst into a polymerization reactor, the inside of which has been brought into fluidized state by particles previously fed therein, which process is characterized in that the polymerization reactor temperature is controlled by vaporizing a part of the styrenic monomer which has been introduced into the polymerization reactor, while the inside of the reactor is maintained under reduced pressure. According to the above process, such problems as difficulty in polymerization reactor scale-up, adhesion of polymer to the reactor inside and polymer particle agglomerate are simultaneously solved, and thereby the industrial significance of the process is remarkably enhanced.

Abstract: A process for the preparation of an aromatic carbonate or polycarbonate from a phenol or bisphenol, methanol, carbon monoxide and oxygen comprising the steps of 1) reacting phenol or bisphenol with acetic anhydride to form (bis)phenyl acetate; 2) reacting dimethyl carbonate with (bis)phenyl acetate from step 1 to produce a phenyl carbonate or polycarbonate and methyl acetate; and 3) reacting the methyl acetate with carbon monoxide to produce acetic anhydride for use in step 1. In a desirable embodiment the dimethyl carbonate may also be prepared by reaction of methanol, carbon monoxide and oxygen.

Abstract: A process for the continuous conversion of crude lactic acid to a substantially purified lactide or polylactide including the steps of polymerizing the lactic acid to form a prepolymer with subsequent depolymerization to form a crude lactide in the presence of a catalyst. The crude lactide is purified in an improved distillation system in which at least three fractions are formed with the substantially purified lactide removed as an intermediate boiling sidedraw stream. The substantially purified lactide may then be polymerized.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: A process for the continuous production of substantially purified lactide and lactide polymers from an ester of lactic acid including the steps of forming crude lactide in the presence of a catalyst means to form a condensation reaction by-product and polylactic acid and depolymerizing the polylactic acid molecules followed by subsequent purification of the crude lactide in a distillation system. A purified lactide is then polymerized.

Abstract: The invention relates to a regulation method for regulating the temperature in a reactor utilized in the polymerization of olefines. A circulating gas is led to the reactor along a circulating gas flow line, and the circulating gas is cooled by leading part of the circulating gas flowing along a circulating gas flow line along a by-pass flow line through a cooler. A regulating device for the circulating gas inlet-flow temperature controls the amount of the circulating gas by-pass flow along a circulating gas by-pass flow line through the cooler such that the sum of the openings of a valve in the circulating gas flow line and a valve in the circulating gas by-pass flow line is maintained substantially constant in the range from about 90 to about 120%.

Abstract: Methods and apparatus are disclosed for removing undesirable volatile components having high boiling points from a product stream during polymerization of monovinyl aromatic compounds such as styrene, which methods include the use of partial condensers, devolatilizers, and filter beds.

Abstract: A process for producing a styrenic copolymer for injection molding or extrusion molding by continuous mass polymerization of a styrenic monomer with a polymerizable unsaturated fatty acid, charcterized by using a polymerization apparatus comprising a circulation polymerization line (I) in which a tubular reactor with plural mixing elements fixed therein is incorporated, said mixing elements having no mobile parts, and a second non-circulation polymerization line (II) provided in succession to said circulation polymerization line (I), in which a tubular reactor with plural mixing elements fixed therein is incorporated, said mixing elements having no mobile parts; and supplementing the polymerizable unsaturated fatty acid to at least two spots of the second non-circulation polymerization line (II).

Abstract: A process for the preparation of a polycarbonate comprising reacting a diaryl carbonate with a bisphenol to produce a polycarbonate and a phenol, regenerating the diaryl carbonate by reacting the phenol byproduct with a carbonyl halide, and optionally recycling the hydrogen halide using a metal Redox captive halogen swing reactor system.

Abstract: In a method and apparatus for the production of thermoplastic, caprolactam containing molding compositions by hydrolytic polymerization of caprolactam in stirrer autoclaves in which a molten mass is polymerized at pressures of 5 to 20 bar and temperatures of 220.degree. to 280.degree. C., the molten mass is transferred into an intermediate vessel to which vacuum is applied for continued polymerization and removal of volatile portions. Subsequently, the mass is continuously fed into a multi-screw extruder, in order to attain at increased temperatures and vacuum the desired polymerization degree and the desired monomer and oligomer contents. In a subsequent zone of the extruder, when desired, additional agents are worked in, whereafter a further degasification occurs in the end zone of the extruder, whereafter the mass is extruded, quenched, subdivided and dried. The method and apparatus use relatively little energy as compared with the prior art.

Abstract: This invention relates to a novel horizontal fluid bed reactor, which in a single unit, provides for the polymerization of monomer to polymer and mixed monomers to copolymers. Within one reactor shell the reactor contains a plurality of polymerization stages which permit the achievement of narrow residence time distribution of the produced polymer. This arrangement also creates a sufficiently tight subdivision of the reactor volume which permits a plurality of gas circulation stages of different gas compositions, as well as, polymerization temperatures.

Abstract: A process for the continuous production of polylactide polymers from lactic acid which incorporates removal of water or a solvent carrier to concentrate the lactic acid feed followed by polymerization to a low-molecular-weight prepolymer. This prepolymer is fed to a reactor in which a catalyst is added to facilitate generation of lactide, the depolymerization product of polylactic acid. The lactide generated is continuously fed to a distillation system as a liquid or vapor wherein water and other impurities are removed. The resultant purified liquid lactide is fed directly to a polymerization process.

Abstract: Lactide monomers and copolymers may be polymerized by a continuous process using one or more continuous stirred tank reactors. The process offers productivity and product quality advantages over the batch process of polymerization.

Abstract: In an ongoing process for the production of polypropylene polymer, propylene monomer is contacted with a polypropylene polymerization catalyst under polymerization conditions in the presence of molecular hydrogen to control polymer molecular weight and polymer properties such as melt flow. Production of polymer having increased or decreased melt flow is achieved by contacting at least a portion of the recycle gas with a metal hydride or metal hydride precursor under conditions whereby the hydrogen concentration of the recycle gas and thus the polymerization reactor is increased or decreased, respectively. The increase or decrease in hydrogen concentration in the polymerization reactor results in production of polypropylene polymer product of higher or lower melt flow.

Abstract: In accordance with the invention, the process comprises substantially eliminating distributor plate fouling in fluid bed reactor alpha olefin polymerizations, by removing oligomers from the recycle feeds to the fluid bed reactor. In accordance with the invention, the process comprises substantially eliminating gel production in the low pressure production of polymers and copolymers of ethylene. Unexpectedly, the process of the invention, which substantially eliminates distributor plate fouling also results in polymer products which are substantially free of gels.

Abstract: A continuous thermal polymerization process for the manufacture of cyclic hydrocarbon resins. The molecular weight of polymerized cyclic hydrocarbon resins is controlled with selected process temperatures for the feed, selected times in the reactor, and recycle of thermal polymerized product.

Abstract: To produce a graded index polymer there is diffused into a base material formed of at least one partly polymerized monomer adapted to yield a homopolymer with refractive index N1 in the gel state an additive material formed of at least one monomer adapted to yield a homopolymer with refractive index N2 different from N1. The polymerization of the base material treated in this way is then completed. The additive material comprises a mixture of at least two monomers and the composition of this mixture is varied with time.

Abstract: A novel process for production of polyethylene comprises polymerizing ethylene or a mixture of ethylene and a copolymerizable comonomer in the presence of a Ziegler-type catalyst at a pressure of 200 atm or more and at a temperature of 125.degree. C. or more, wherein an organic peroxide is added to the resulting polymerization product taken out of a reaction zone to deactivate the remaining catalyst. Formation of undesired oligomers or low-molecular polymers is prevented because the reaction does not proceed in the polymerization product taken out of the reaction zone. There is almost no retardation of the polymerization reaction even by the recycled use of the monomer separated and collected from the polymerization product.

Abstract: Ethylene/.alpha.-olefin copolymers are prepared by catalytic dry-phase copolymerization of the monomers in a stirred or fluidized polymerization zone, transfer of the resulting mixture of solid copolymer and unconverted gaseous monomer into a let-down zone and separation of the mixture, after pressure reduction, into a gaseous phase and a solid phase, by a continuous process in which the solid phase is continuously flushed beforehand with gaseous ethylene and then flushed with a mixture of nitrogen and steam. The ethylene copolymers are very substantially free of residual monomers and odor and flavor substances.

Abstract: A process for the continuous preparation of a linear polyamide having ether bridges in the polymer chain, in which an aqueous solution of a salt of a diamine and an equimolar amount of a dicarboxylic acid, which may additionally contain a lactam or the corresponding aminocarboxylic acid, from 1 to 80% of the polyamide-forming units, based on the total polyamide-forming units, being diamine and/or dicarboxylic acid units which, after removal of the amine groups or carboxyl groups, have radicals of formula I--R.sup.1 --O--R.sup.2 --O]R.sup.3 -- I,in which R.sup.1, R.sup.2 and R.sup.

Abstract: A process for producing a branched polycarbonate by an interfacial polycondensation method comprising condensing a first reaction mixture comprising an inert organic solvent, an alkaline aqueous solution of divalent phenol, a branching agent, and phosgene, the branching agent having a partition coefficient of at least 1, wherein the partition coefficient is defined as the ratio of the concentration in inert organic solvent/concentration in water, to form a second mixture containing a polycarbonate oligomer or a polycarbonate and unreacted branching agent, separating the second mixture into an organic solvent layer and an aqueous layer which contains the unreacted branching agent, extracting the unreacted branching agent from the aqueous layer with inert organic solvent and recycling the inert organic solvent which contains the unreacted branching agent extracted from the aqueous layer to the first reaction mixture.

Abstract: Copolyamides are prepared by a continuous process in which(a) an aqueous solution of salts of equimolar amounts of diamines and dicarboxylic acids is passed, under superatmospheric pressure and with simultaneous evaporation of water, through a tubular precondensation zone with formation of a vapor phase and a prepolymer at above the melting point of the prepolymer,(b) the vapor phase is separated from the prepolymer melt,(c) the vapor phase is separated in a column into steam and an aqueous diamine solution, and the aqueous solution containing diamines is recycled to the polymerization,(d) the prepolymer melt is mixed with molten caprolactam at polyamide-forming temperatures, and(e) the mixture of prepolymer and caprolactam is passed downward through a vertical polymerization tube at polyamide-forming temperatures and a copolyamide is obtained.

Abstract: A process for reducing sheeting during gas phase polymerization of alpha-olefins utilizing catalysts prone to cause sheeting wherein the gaseous feed stream containing monomer comonomer hydrogen and inert gas is introduced into the reactor through the recycle stream to the reactor at a point prior to cooling the recycle stream.

Abstract: Copolyamides which contain units of the formula --NH--(CH.sub.2).sub.4 --NH are prepared by a continuous process in whicha) an aqueous solution of from 5 to 80% by weight of a salt of 1,4-diaminobutane, and dicarboxylic acids and from 20 to 95% by weight of further polyamide-forming starting materials are heated to a temperature above the melting point of the copolyamide, with the addition of diamines and with vaporization of water, under superatmospheric pressure,b) the vapor phase and prepolymer are brought into intimate contact with one another,c) the prepolymer is separated from the vapor phase and the polymer is discharged after a total residence time of not more than 30 minutes, andd) diamines are separated off from the vapor phase and recycled to a).

Abstract: A free-radical initiated process for preparing fluorinated polymers wherein at least one gaseous fluoroolefin is polymerized in a stirred polymerizer, the improvement comprising preparing a non-volatile polymeric seed in a reaction zone separate from the polymerizer by decomposing initiator in the presence of fluoromonomer to form oligomeric free radicals and condensing said radicals onto previously prepared polymer; and conveying said non-volatile seed to the polymerizer.

Abstract: Polymer having a polymodal MWD ethylene copolymer are prepared by conducting the polymerization in a substantially mix free reactor using an essentially transfer agent free reaction mixture, the reaction being carried out in a manner such that the propagation of essentially all copolymer chains is initiated simultaneously. In carrying out the process of this invention, the catalyst components are premixed and aged prior to introduction into the reactor. The process is preferably carried out in a tubular reactor using VCl.sub.4 and aluminum sesquichloride as the catalyst system.

Abstract: A process for the continuous preparation of polytetramethylene adipamide, in which(a) an aqueous solution of the salt of 1,4-diaminobutane and adipic acid is heated with evaporation of water to form a vapor phase and a molten prepolymer,(b) the said prepolymer and vapor phase are passed, to effect thorough mixing thereof, through a mass transfer zone equipped with baffles and located immediately downstream of stage (a),(c) the said vapor phase is separated from the polymer in a separting zone and the polymer is discharged in the form of a melt capable of being granulated, with the proviso that the total residence time in stages (a), (b) and (c) is less than 5 minutes, and(d) pyrrolidine is distilled off from the vapor phase separated in stage (c) and 1,4-diaminobutane is recycled to the vaporizing stage (a).

Abstract: A homogeneous, random interpolymer of ethylene and an alpha-olefinically unsaturated carboxylic acid or ester having a melt flow rate in the range of about 0.1 to about 300 g/10 minutes, as determined by ASTM D-1238 (190.degree. C./2160 g), is improved during its manufacture when made in a substantially constant environment in a stirred autoclave under substantially steady-state conditions of temperature, pressure, and flow rates, said temperature and pressure being sufficient to produce a single phase reaction, using a free-radical initiator, said improvement being obtained by the use of a minor amount of a telogenic modifier in the reaction mixture, the process being further characterized by the use of either, or both, of (a) a temperature which is lower than that which would be required without the presence of the telogen, or (b) a pressure which is higher than that which would be required without the presence of the modifier.

Abstract: Continuous processes for producing high melting and viscoelasting polypropylene or ethylene-propylene copolymer are provided.These processes are characterized by (1) using two or more polymerizers connected in series, (2) supplying the whole amount of a catalyst and a molecular weight regulator (hydrogen) in the first tank and (3) a degasification amount of each tank in the second and subsequent tanks being 0.5 to 10 V.sub.1 /Hr (wherein V.sub.1 is a volume of the tank) calculated at 0.degree. C., and 0 Kg/cm.sup.2 G. In the process for producing the copolymer, (4) monomers having an ethylene content of 5 wt % or less are supplied in the first step. According to the processes of the present invention, polymers having a broad molecular weight distribution and good fluidity upon extrusion molding can be obtained and operational control in production is simply made.

Abstract: This invention relates to an integrated process for producing polycarbonates by transesterification of a dialkyl carbonate with a bisphenol diester to form a carbonate oligomer and an alkyl ester followed by polymerization of the oligomer to a polycarbonate. The feature of the invention lies in the carbonylation of the alkyl ester by-product formed during the transesterification step to an ahydride which is used to esterify bisphenol to the diester.

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 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: 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: A continuous flow process for the production of high impact polystyrene, wherein specific types of polymerization inhibiting impurities are removed from a recycle stream prior to feeding or introducing the recycle stream into a styrene polymerization zone. Preferably, the process further comprises the step of monitoring the acidity of the recycle stream.

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.