Abstract: Disclosed is a process for preparing a polymer solution having a reduced unreacted unsaturated monomer content, comprising radically polymerizing at least one unsaturated monomer in a solvent in the presence of a radical polymerization initiator, the at least one unsaturated monomer having a lower boiling point than that of the solvent, wherein the weight ratio of the total amount of the unsaturated monomers to the solvent is from 1/9 to 7/3, the polymerization is carried out until the conversion of the unsaturated monomer having the lowest conversion of all the other unsaturated monomers whose boiling point is lower than that of the solvent reaches at least 85%, and, after completion of the polymerization, the reaction mixture is rectified to remove the unreacted unsaturated monomer or monomers.

Abstract: In a process for preparing formaldehyde from methanol by dehydrogenation in a reactor in the presence of a catalyst at a temperature in the range from 300 to 1000° C., a circulating gas stream comprising by-products of the dehydrogenation is passed through the reactor.

Abstract: Polybutylene terephthalate having good heat stability and excellent hydrolysis resistance is continuously produced in a series of a first reactor for reacting an aromatic dicarboxylic acid comprising terephthalic acid as a main ingredient or a derivative thereof with a glycol comprising 1,4-butanediol as a main ingredient, thereby producing an oligomer with an average degree of polymerization of 2.2 to 5, a second reactor for polycondensating the oligomer from the first reactor, thereby preparing a low polymerization product with an average degree of polymerization of 25 to 40, and a third reactor for further polycondensating the low polymerization product from the second reactor, thereby producing a high molecular weight polyester with an average degree of polymerization of 70 to 130, or followed by a fourth reactor for further polycondensing the polyester from the third reactor to an average degree of polymerization of 150 to 200, thereby producing a high molecular weight polyester.

Abstract: This invention relates to a method for removing unreacted monomers and other volatile matters from a polymer solution composition produced from a mixture containing an aromatic vinyl monomer, utilizes two or more flash devolatilizing vessels, and effects the removal by adjusting the solid content of the polymer solution composition at the outlet of the devolitilizer before the last-stage devolitilizer to a level in excess of 97%, adding 0.5-4 parts by weight of a foaming agent to the total polymer solution composition, passing the polymer solution composition through the last-stage devolitilizer while maintaining the pressure of the polymer solution at 10 kg/cm2 or more by means of a pressure controller and the temperature in the range 190-260° C., introducing the polymer solution composition to a vapor-liquid separation vessel maintained at a vacuum of 20 Torr or less, and allowing the composition to foam.

Abstract: A continuous process for the production of poly(trimethylene terephthalate) is disclosed. According to the process, a liquid feed mixture comprising bis-3-hydroxypropyl terephthalate and/or low molecular weight polyesters of 1,3-propanediol and terephthalic acid, the liquid feed mixture having a mole ratio of propylene groups to terephthalate groups of 1.1 to 2.2 is fed to a prepolymerizer. Bis-3-hydroxypropyl terephthalate and the low molecular weight polyesters are continuously polymerized to form a poly(trimethylene terephthalate) prepolymer and a first stream of gaseous by-products. Poly(trimethylene terephthalate) prepolymer having a relative viscosity of at least about 5 is continuously withdrawn from the prepolymerizer and continuously fed to a final polymerizer, where it is continuously polymerized to form a higher molecular weight poly(trimethylene terephthalate) and a second stream of gaseous by-products.

Abstract: A process is disclosed for removing particulate product from a fluidized bed reactor to optimize, within the constraints of the product removal cycle, conservation of gas in which the product is entrained. Data are compiled on the time required for equalizing pressure between product discharge tanks, and these data are used to determine the optimum times for various valves to be open. Product movement steps and equalization steps can be performed simultaneously.

Abstract: A method for removing contaminants from an organic-based feed stream which includes the use of a layer of reticulated ceramic material to filter the organic-based feed stream and to provide liquid distribution upstream of the catalyst bed.

Abstract: The present invention relates to an improved catalyst delivery method for introducing a supported bulky ligand metallocene-type catalyst system to a reactor for polymerizing one or more olefin(s). In particular, the invention provides for a method of introducing a supported metallocene-type catalyst system into a polymerization reactor by and in the presence of a carrier solution of an antistatic agent and a liquid diluent. Also, the invention is directed toward a catalyst feeder for use in a polymerization process.

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: A method for removing contaminants from an organic-based feed stream which includes the use of a layer of reticulated ceramic material to filter the organic-based feed stream and to provide liquid distribution upstream of the catalyst bed.

Abstract: A process is disclosed for removing particulate product from a fluidized bed reactor to optimize, within the constraints of the product removal cycle, conservation of gas in which the product is entrained. Data are compiled on the time required for equalizing pressure between product discharge tanks, and these data are used to determine the optimum times for various valves to be open. Product movement steps and equalization steps can be performed simultaneously.

Abstract: A process for preparing polytrimethylene terephthalate in which a carbonyl-containing 1,3-propanediol stream is purified for reuse of the 1,3-propanediol. The process involves reacting, under condensation polymerization conditions, terephthalic acid and a molar excess of 1,3-propanediol, with vacuum distillation and condensation of a major portion of the unreacted 1,3-propanediol. To this condensed stream is added a sufficient amount of base to raise the pH to a value greater than 7, and from this base-containing condensate the 1,3-propanediol is distilled and recycled to the polymerization reaction.

Abstract: An apparatus for depolymerizing recycled polyester into its component ester monomers and half esters includes a first reactor for depolymerizing the recycled polyester, a separator for separating ester monomeric components and half-esters from secondary materials produced in the first reactor, and a second reactor for producing a low molecular weight polyester from liquefied separator products.

Abstract: The present invention relates to apparatus for the semi-continuous polymerization of monomers with the use of a chain initiator. This apparatus is characterized in that it comprises a reactor (1) arranged with its axis substantially vertical and defining a lower, frustoconical part (III), an upper atonization part (I) and an intermediate part (II), the reactor (1) having monomer and initiator inlet apertures (8, 10, 20, 21) at least one outlet aperture (12), a recycling duct (15) connected at one end to the outlet aperture (12) and at the other end to the upper part (I) through at least one atomizer (9), and a stirrer (25). The apparatus according to the invention has the particular advantage of being usable for reactions with any type of chain initiator and catalyst, whether they are solid, liquid or in suspension.

Abstract: This invention provides a method of producing polyester and charging apparatus therefor capable of producing a high quality polyethylene naphthalate usable for photographic purpose from recovered polyethylene naphthalate which comprises subjecting an ester-forming derivative consisting essentially of naphthalene dicarboxylic acid or its lower alkyl ester and a diol compound consisting essentially of ethylene glycol to ester exchange reaction or esterification to produce polyethylene naphthalate, wherein recovered polyethylene naphthalate resin is charged before beginning of effusion of alcohol or water which is a by-product of the ester exchange reaction or esterification, and a charging apparatus comprising a slidable inner pipe capable of penetrating through a supply valve.

Abstract: A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia.

Abstract: A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia.

Abstract: The process for preparing polyethylene naphthalate according to the invention is intended to obtain polyethylene naphthalate having a low impurity content from naphthalenedicarboxylic acid containing impurities.

Abstract: An apparatus for continuously producing polyester comprises three single reactors, i.e. a single esterification reactor (first reactor), a single initial polymerization reactor (second reactor) and a single final polymerization reactor (third reactor or final polymerizer), where at least one of the first reactor and the second reactor is free from an external stirring power source, or the third reactor is a horizontal, one-shaft-type, low speed rotation type reactor. Necessary number of reactors for the esterification and polycondensation reactions can be a minimum and necessary stirring power consumption for the reaction can be a miminum, and thus polyester polymers of good quality can be efficiently produced at a minimum energy cost in a necessary minimum reactor structure.

Abstract: An apparatus for converting PET into polyester polyols including a reactor vessel having an interior volume, a stirring member rotatably mounted inside the reactor vessel and adapted to stir contents of the reactor vessel, a rotation device connected to the stirring member and adapted to rotate the stirring member in the reactor vessel, and a heater interactive with the interior of the reactor vessel so as to elevate the temperature of the interior volume of the reactor vessel to at least 175.degree. C. The reactor vessel has an inner wall and an outer wall with a space therebetween. The heater passes a heated fluid into the space between the inner wall and the outer wall. The stirring member includes a tubular member extending through the interior volume of the reactor vessel and a plurality of stirring arms extending radially outwardly of the tubular member. The heater serves to pass heated fluid through the interior of the tubular member and into the interior passageway of the stirring arms.

Abstract: A method is disclosed of producing a copolymer of polyethylene terephthalate and polyethylene naphthalate. The method comprises esterifying a combination of a diester of naphthalene, terephthalic acid, and ethylene glycol to produce an esterification reaction mixture that includes the alcohol byproduct of the naphthalene diester, distilling the reaction mixture to remove at least a portion of the esterification byproducts from the reaction mixture in the form of a vapor stream of which the majority component is water vapor and which includes the alcohol byproduct of the naphthalate ester in the vapor state, and combusting at least a portion of the vapor stream under conditions sufficient to decompose at least a portion of the alcohol byproduct present in the vapor stream.

Abstract: The invention relates to a process for preparing blends of high-performance polymers. The particular features are that at least two single-type polymers are treated with a solvent or a solvent mixture in which the polymers used are soluble, the polymers are thereby dissolved, and are then precipitated in a liquid medium, and recycled material is used for each of the polymeric constituents.

Abstract: Claimed is a copolyether amide having a melting point in the range of 180.degree. to 260.degree. C., incorporating at least 10 wt. % and not more than 30 wt. % of ethylene oxide groups, and composed of 30 to 60 wt. % of polyamide segments and 70 to 40 wt. % of segments derived from a (cyclo)aliphatic or aromatic dicarboxylic acid or a dimeric fatty acid and a polyoxyalkylene diamine derived from a polyoxyalkylene group having a molecular weight of 600 to 6000 and an atomic ratio of carbon to oxygen of 2.0 to 4.3. Also claimed is a non-porous, waterproof film having a water vapor permeability of at least 1000 g/m.sup.2 day determined at 30.degree. C. and 50% RH in accordance with ASTM E96-66 which is based on a the use of these films in rainwear, shoes, tents, chairs, as mattress covers and underslating, for medical purpose garments, and for the manufacture of dressings.

Abstract: A high quality copolymer of styrene and methyl methacrylate is economically produced by polymerizing styrene and methyl methacrylate in a homogeneous solution of raw materials comprising methyl methacrylate, styrene, and an antioxidant, while the solution of raw materials is continuously supplied to a polymerization reactor including at least one complete-mixing type reaction tank, continuously removing the polymerization product from the polymerization reactor, supplying the polymerization product removed from the polymerization reactor directly to an extruder having a plurality of vents, and extruding a copolymer from the extruder, while volatile matter are removed through the plurality of vents.

Abstract: A process for the continuous preparation of thermoplastic polyesters bya) a first step of (trans)esterifying a dicarboxylic acid or its esters or ester-forming derivatives with a molar excess of a dihydroxy compound,b) a second step of precondensing the (trans)esterification product of a), andc) a third step of polycondensing the product of b)comprises carrying out step a) and/or step b) of the process in two or more temperature zones.

Abstract: A process for producing a polyester of uniform quality, in which a slurry of powdery aromatic dicarboxylic acid in a liquid diol is prepared and the resulting slurry is processed through an esterification step and a polycondensation step in the presence of a catalyst, is provided by performing the reactions in the esterification and the polycondensation in a stabilized condition, which process comprisesrecycling a liquid containing the unreacted diol and the catalyst separated from the reaction mixture in the polycondensation step back to the esterification step as recycling liquor,detecting the concentrations of diol, diol condensation product, catalyst and water in the recycling liquor in the course of being recycled back to the esterification step by a near infrared spectrophotometer of a noise level of at the highest 50.times.10.sup.-6 Abs with a wave length repeatability of 0.

Abstract: Water recovered from the polymerization of vinyl monomers can be treated to remove or deactivate chain transfer agents present in the water allowing resuse in polymerization processes. The water recovered from a vinyl polymerization reaction is contacted with a cation exchange resin in the hydrogen form prior to recycle, or may be acidified and then contacted with an anion exchange resin in the hydroxide form.

Abstract: The present invention provides a method capable of continuously efficiently producing a 2-hydroxycarboxylic acid oligomer while effectively removing the water contained in a raw material and the water produced by dehydration reaction. In production of a 2-hydroxycarboxylic acid oligomer by supplying a 2-hydroxycarboxylic acid to a reaction system, a dehydration system is provided between a raw material supply system and a polymerization reaction system so as to remove the water contained in the raw material and the water produced in the polymerization reaction system. As a result, the raw material in the dehydration system is concentrated and then supplied to the polymerization reaction system.

Abstract: Claimed is a copolyether amide having a melting point in the range of 180.degree. to 260.degree. C., incorporating at least 10 wt. % and not more than 30 wt. % of ethylene oxide groups, and composed of 30 to 60 wt. % of polyamide segments and 70 to 40 wt. % of segments derived from a (cyclo)aliphatic or aromatic dicarboxylic acid or a dimeric fatty acid and a polyoxyalkylene diamine derived from a polyoxyalkylene group having a molecular weight of 600 to 6000 and an atomic ratio of carbon to oxygen of 2.0 to 4.3. Also claimed is a non-porous, waterproof film having a water vapour permeability of at least 1000 g/m.sup.2 day determined at 30.degree. C. and 50% RH in accordance with ASTM E96-66 which is based on a the use of these films in rainwear, shoes, tents, chairs, as mattress covers and understating, for medical purpose garments, and for the manufacture of dressings.

Abstract: A process is disclosed for the crystallization of a PEN prepolymer containing volatile components. The temperature is maintained in the range of about 20.degree. C. above the Tg and about 10.degree. C. below the Tm while the PEN prepolymer is agitated. The PEN prepolymer is present as chips or pellets. The crystallization is performed in the presence of a liquid or a mixture of liquids that do not degrade the polymer during crystallization. The liquid or liquids employed may be those whose vapor pressure at the amorphous PEN softening temperature are insufficient to forestall expansion of the pellets. When this class of liquid or liquids is employed, the crystallization vessel is pressurized with an inert gas, including air, to prevent the prepolymer expansion. If the liquid or liquids possess sufficiently high vapor pressures at the PEN softening temperature, the pellets do not expand even without the inert air pressurization.

Abstract: Apparatus for preparing a polyester resin by polymerizing a monomer produced by transesterifying a dicarboxylic acid component with a diol component while removing the vapor containing diols and other low molecular weight compound released during the polymerization, which comprises:a polymerization reactor;a condenser having an inlet, a heat exchanger and an outlet, the inlet being located below the heat exchanger and connected to the polymerization reactor while the outlet being positioned above the heat exchanger;a baffle installed between the inlet and the heat exchanger of the condenser such that the flow of the vapor is directed toward the bottom of the condenser;a trap located below the condenser to collect the condensate of the vapor; anda vacuum pump connected to the outlet of the condenser.

Abstract: Multiple sequential chemical reactions on a polymeric feedstock are carried out in an extruder with multiple reaction zones. Each reaction zone has means for introduction of reagents, for mixing of reagents with polymer and for removal of by/co-products or unreacted reagents.

Abstract: A catalyst composition for use in a polycondensation reaction for making poly(ethylene terephthalate) from terephthalic acid comprising: (a) an antimony salt catalyst present in a range from about 10 to about 1,000 ppm; (b) a metal salt catalyst of at least one of cobalt, magnesium, zinc, manganese, calcium, and lead, present in a range from about 10 to about 500 ppm; and (c) an alkali metal acetate, present in a range from about 10 to about 500 ppm; all amounts are based on the metallic elements relative to the theoretical yield of the poly(ethylene terephthalate), by weight, to be made from the terephthalic acid. The catalyst composition was found to have increased the reaction rate in the production of poly(ethylene terephthalate), as well as improved the color of the produced product, by reducing the degree of yellowness in the final poly(ethylene terephthalate) product. Attenuation of the yellowish color indicates a reduction in the amount of undesired side reaction product.

Abstract: A catalyst composition for use in a polycondensation reaction for making poly(ethylene terephthalate) from terephthalic acid comprising: (a) an antimony salt catalyst present in a range from about 10 to about 1,000 ppm; (b) a metal salt catalyst of at least one of cobalt, magnesium, zinc, manganese, calcium, and lead, present in a range from about 10 to about 500 ppm; and (c) a phosphorus salt co-catalyst selected from the group consisting of alkali metal phosphates, alkali metal phosphites, alkali metal hypophosphites and alkali metal polyphosphates, present in a range from about 10 to about 500 ppm; all amounts are based on the metallic or phosphorus element relative to the theoretical yield of the poly(ethylene terephthalate), by weight, to be made from the terephthalic acid.

Abstract: Multiple sequential chemical reactions on a polymeric feedstock are carried out in an extruder with multiple reaction zones. Each reaction zone has means for introduction of reagents, for mixing of reagents with polymer and for removal of by/co-products or unreacted reagents.

Abstract: The present invention relates to a process for the preparation of polycarbonates in which an oil-in-water emulsion is maintained throughout by employing special reaction conditions.

Abstract: The present invention discloses a polymerization system having at least two reaction chambers wherein vacuum is used to remove vapors therefrom comprising a single vacuum system for supplying vacuum in increasing amounts to successive reaction chambers.

Abstract: A method for preparing a polymer rod for optical transmission media. The process involves copolymerization of monomers having different boiling points by removal of monomer vapor during polymerization. The process results in a transition in refractive index along the radial direction of the polymer rod.

Abstract: Process for producing ethylene-vinyl ester copolymers using a polymerization solvent of a dialkyl sulfoxide (process X); process for producing ethylene-vinyl alcohol copolymer by liquid phase saponification using a solvent of a dialkyl sulfoxide (process Y); and process for producing shaped articles which comprises contacting the ethylene-vinyl alcohol copolymer obtained by the process Y, or that obtained by saponifying the ethylene-vinyl ester copolymer obtained by process X, to a non-solvent for ethylene-vinyl alcohol copolymer.Ethylene-vinyl ester copolymers having a wide range of ethylene content and higher degree of polymerization than that with solution polymerization using methanol.The rate of saponification is higher than that with single solvent system of lower alcohol.Production cost is low, because production process of polymer is directly connected to that of shaped articles utilizing the polymer.

Abstract: A method for recovering unreacted monomers during preparation of a vinylic polymer comprises the steps of polymerizing a vinyl monomer in an aqueous medium in a polymerizer and then recovering unreacted monomers from the polymerization system, wherein a gas evacuation rate per unit charge weight of the monomer is controlled to the range of from 60 to 300 Nm.sup.3 /hr per ton of the monomer from the initiation of the monomer recovery till the pressure in the polymerizer reaches 2.5 kg/cm.sup.2 G and a superficial gas linear velocity is reduced to a level of not more than 0.008 m/sec when the pressure in the polymerizer reaches 2.5 kg/cm.sup.2 G. The method makes it possible to recover unreacted monomers quickly without causing carrying over of polymer particles formed and is effective to maintain high quality of vinylic polymers produced.

Abstract: A process for preparing a porous and water-absorbent resin which includes dispersing an aqueous solution containing at least one .alpha.,.beta.-unsaturated carboxylic acid monomer, its alkali metal salt or its ammonium salt in a hydrophobic organic solvent, and conducting a reversed phase suspension polymerization by using a water-soluble radical polymerization initiator, while distilling away the hydrophobic organic solvent together with water. A porous and water-absorbent resin having excellent absorbency and a remarkably improved rate of water absorption can be easily and efficiently obtained on an industrial scale.

Abstract: An extrusion polymerization process is described in which the polymerization of vinylic monomers, in particular acrylic monomers, is carried out in bulk in an extruder. The polymerization reaction is catalysed by a catalyst composition comprising an initiator, e.g. a ureido substituted silane, and a co-catalyst which is a salt providing a source of anions, e.g. fluoride ions.

Abstract: A suspension polymerization process for the preparation of a polymeric material formed from at least two monomers, a non-gaseous monomer and a gaseous monomer. The composition of the beads or particles of the polymeric material is controlled by adding gaseous monomer to the vapor phase after polymerization of about 5% to about 90% by weight of the non-gaseous monomer or by removing a portion or substantially all of the gaseous monomer in the vapor phase before polymerization of about 70% by weight of the gaseous monomer in the aqueous suspension, or a combination thereof.

Abstract: In an improved continuous process for the production of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon by contacting the carbon monoxide and hydrocarbon under polymerization conditions in the presence of a reaction diluent and a catalytic quantity of a catalyst composition formed from a compound of palladium, the anion of a strong non-hydrohalogenic acid and a bidentate ligand of phosphorus, an improved start-up procedure is employed in which the catalyst composition concentration in the reaction diluent is increased until steady state polymerization is reached.

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: In a dispersion system comprising seed polymer particles and a monomer, the solubility of the monomer is reduced by such means as addition of water, whereby the monomer is precipitated and absorbed in the seed polymer particles, and in this state, the monomer absorbed in the seed polymer particles is selectively polymerized.Namely, according to the present invention, the decrease of the solubility of the monomer in the dispersion system is utilized for absorption of the monomer in the seed polymer particles, and polymer particles having an increased particle size can be prepared in a short time at a high efficiency.

Abstract: In a separation system (1 to 11) for tube reactors or autoclaves, which are used for the polymerization of ethylene or copolymerization of ethylene with ethylenically unsaturated comonomers in the presence of an initiator under from 500 to 4,000 bar and at from 150.degree. to 350.degree. C., for reducing the emission of solids during pressure relief processes of the reaction mixture present in the reactor or autoclave, the reaction mixture let down is fed via two or more separating containers (1, 1a) installed in series before it reaches the atmosphere.

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: Removing chloroprene dimers from polychloroprene by feeding to a screw extruder a polychloroprene latex and coagulating the latex in the extruder, feeding the coagulated latex to a dewatering zone and discharging the coagulated polychloroprene through a flow restriction which heats and pressurizes the polychloroprene to an area of reduced pressure to form a porous crumb. Also, the flow restriction applies back pressure sufficient that the water in the polychloroprene is forced out of a vent port. The polychloroprene crumb discharged from the extruder is heated to strip chloroprene dimer therefrom.

Abstract: The danger of explosion due to decomposition of high-pressure industrial process gases, such as ethylene, is reduced by beginning to cool the decomposition gases with a delay of no more than 25 milliseconds from the onset of flow of the gases out of a high-pressure vessel. The process may be implemented by using apparatus comprising: (1) means containing an inert gas at a pressure P between about 5 and 50 bars and an inert liquid of high heat of vaporization; and (2) a valve located upstream of an inert-liquid dispersing means, of which the opening is operated by a means detecting the opening of a safety means of the high-pressure vessel and operating the working of the dispersing means.