Abstract: A continuous process for preparation of propylene-ethylene block copolymer suitable for moldings with high rigidity and high impact resistance are provided, which process is a continuous process for preparation of highly rigid propylene-ethylene block copolymers, wherein propylene and ethylene are polymerized in the specified 2 steps with use of a catalyst system comprising (A) a solid catalyst component containing Ti, Mg, halogen and polyvalent carboxylic ester, (B) an organic aluminium compound, as well as (C) an organic silicon compound expressed by the general formula R.sup.4.sub.x R.sup.5.sub.y Si(OR.sup.6).sub.z (wherein, x+y+z=4), and wherein the ratio between the maximum value and the minimum value of MFR(l)) is0.1.ltoreq.Log(MFR(h)/MFR(l)).ltoreq.1,and the ratio between the average MFR(i) and MFR(ii) in the subsequent polymerization procedure (II) containing ethylene in a relatively large amount which is carried out by adding the glycol type compound is3.ltoreq.Log(MFR(i)/MFR(ii)).ltoreq.7.

Abstract: Toughened thermoplastics are prepared by mixing a water-moist elastomer component A containing up to 60% by weight of residual water with a thermoplastic polymer B and further polymers C and additives D in an extruder with mechanical dewatering of the elastomer component A, by a process in which the components A, B, C and D are fed to a twin-screw extruder which has corotating screws and essentially comprises, in the transport direction,at least one metering section in which the elastomer component A is fed to the extruder by a metering means,at least one squeeze section which serves for dewatering the component A and contains at least one retarding element and in each case at least one associated dewatering orifice,at least one section in which the thermoplastic polymer B is introduced as a melt into the extruder,at least one section provided with mixing, kneading or other plasticating elements or combinations of these elements,at least one devolatilization section which is provided with at least one devolat

Abstract: A continuous process for the preparation of highly stable, finely divided, low viscosity polymer polyols of small average particle size wherein in the first step an intermediate is prepared by reacting (1) a mixture of at least two ethylenically unsaturated monomers, preferably styrene and acrylonitrile, in a mixture comprising (2) a base polyol and (3) a macromer in the presence of (4) a free radical initiator, (5) a solvent having moderate chain transfer activity, and, optionally, (6) a reaction moderator at a temperature of at least 100.degree. C., such that the intermediate contains at least about 12% by weight of macromer, based on the weight of the base polyol and macromer, and a solids content of at least about 15% by weight and less than about 30% by weight, based on the weight of the base polyol, macromer and ethylenically unsaturated monomers.

Abstract: Toughened vinyl aromatic compounds, in particular high impact polystyrene, are prepared by a continuous process in which the vinyl aromatic compound and the impact modifier, an elastomeric block copolymer, are each prepared separately in a reaction zone by anionic polymerization, with or without heat exchange with the environment and, if required, with the addition of a solvent, and are polymerized until complete conversion is achieved, and the living chain ends are terminated in a manner known per se, and a thermoplastic, toughened molding material is based on a vinyl aromatic compound having a residual content of less than 50 ppm of monomers and less than 100 ppm of oligomers.

Abstract: A blend comprising a mixture of two ethylene/alpha-olefin copolymers, said blend having a flow index in the range of about 5 to about 50 grams per 10 minutes; a melt flow ratio in the range of about 10 to about 50; a density in the range of 0.900 to 0.940 gram per cubic centimeter; a molecular weight in the range of about 98,000 to about 190,000; and an Mw/Mn ratio in the range of about 2 to about 8, said blend having been prepared by mixing first and second copolymers having about equal molecular weights, each copolymer being a copolymer of ethylene and an alpha-olefin having 3 to 8 carbon atoms, the first copolymer having a flow index in the range of about 5 to about 75 grams per 10 minutes; a melt flow ratio in the range of about 10 to about 50; a density in the range of 0.860 to 0.

Abstract: A resin composition containing 50 to 99% by weight of component A, which is a copolymer of ethylene and .alpha.-olefin, and 1 to 50% by weight of component B, which is a high-pressure low-density polyethylene. The component A has (a) a melt flow rate (MFR) of 2 to 30 g/10 min., (b) a density of not more than 0.935 g/cm.sup.3, and (c) a single peak of elution volume indicated by an elution curve obtained by temperature rising elution fractionation, the peak corresponding to a temperature within a range of from 20.degree. C. to 85.degree. C., and the elution curve satisfying a relationship in which the ratio H/W is not less than 1 when H represents the height of the peak and W represents the width of the elution curve at half of the height H. The component B has (a') a melt flow rate of 0.1 to 20 g/10 min., (b') a density of 0.915 to 0.93 g/cm.sup.3, ('c) a memory effect (ME) of not less than 1.6, and (d') a melt tension (MT) of not less than 1.5 g.

Abstract: Highly flexible propylene/ethylene copolymers having a high rubber content are obtainable by two-stage polymerization from the gas phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system which, in addition to a titanium-containing solid component, also contains an aluminum compound as a cocatalyst, in a first polymerization stage, propylene being polymerized at from 15 to 40 bar and from 50.degree. to 90.degree. C. and during an average residence time of the reaction mixture of from 0.5 to 5 hours and then, in a second polymerization stage, a mixture of propylene and ethylene being polymerized with the polymer discharged from the first polymerization stage, at from 5 to 30 bar, this pressure being at least 2 bar below the pressure of the first polymerization stage, and at from 60.degree. to 100.degree. C. and during an average residence time of the reaction mixture of from 0.

Abstract: A sheet such as a geomembrane consisting essentially of an extruded in situ blend of two copolymers of ethylene and one or more alpha-olefins having 3 to 8 carbon atoms, said blend having a flow index in the range of about 3 to about 100 grams per 10 minutes; a melt flow ratio in the range of about 50 to about 200; a density in the range of 0.905 to 0.943 gram per cubic centimeter; an Mw/Mn ratio in the range of about 10 to about 50; and a weight average molecular weight in the range of about 180,000 to about 465,000.

Abstract: A cable comprising one or more electrical conductors or a core of one or more electrical conductors, each conductor or core being surrounded by a layer of insulation comprising a multimodal copolymer of ethylene and one or more alpha-olefins, each alpha-olefin having 3 to 8 carbon atoms, the copolymer having a broad comonomer distribution as measured by TREF with a value for the percent of copolymer, which elutes out at a temperature of greater than 90 degrees C., of greater than about 5 percent; a WTGR value of less than about 20 percent; a melt index in the range of about 0.1 to about 30 grams per 10 minutes; and a density in the range of 0.880 to 0.950 gram per cubic centimeter, and being prepared by a low pressure process.

Abstract: Gas-phase process for the preparation of polymers and copolymers of olefins CH.sub.2 .dbd.CHR, carried out in at least 2 fluidized or mechanically agitated bed gas-phase reactors operating under different reaction conditions so as to obtain different polymers in the different reactors; the process is characterized in that the polymer is at least partially recycled among the different reactors by using ratios of the flow rate of circulation among the different reactors to the discharge flow rate comprised between 2 and 6.

Abstract: A gas phase process for producing olefin polymer graft copolymers, including providing a reaction apparatus having first and second reaction zones operatively connected to each other into which particles of an olefin polymer and a free-radical polymerizable monomer are fed while maintaining free-radical polymerization conditions and a substantial non-oxidizing environment in said zones and from which the grafted copolymer product is discharged. An apparatus suitable for practicing this process is also disclosed.

Abstract: An ethylene polymer which is useful for molding inflation film having a particularly excellent moldability is provided.The ethylene polymer is obtainable by the first and second steps and satisfying the following conditions (a) to (d):(a) the polymer produced in the first polymerization step having an weight average molecular weight (Mw,.sub.1) in the range of 6.times.10.sup.5 to 4.times.10.sup.6 ;(b) the ratio (Mw,.sub.2 /Mw,.sub.1) of the weight average molecular weight of the polymer produced in the first polymerization step (Mw,.sub.1) and the weight average molecular weight of the polymer produced in the second polymerization step (Mw,.sub.2) being in the range of 0.7 to 1.4;(c) the molecular weight in which the integration fraction from the low molecular weight is equal to 1/2 of the weight fraction (W.sub.2) of the polymer produced in the second polymerization step being in the range of 5.times.10.sup.3 to 3.times.10.sup.4 ; and(d) the weight fraction (W.sub.

Abstract: A process and system for prevention of fouling of pressure taps in a first gas phase fluidized bed polymerization reactor while avoiding sheeting during production of polyolefins in a second downstream gas phase fluidized bed polymerization reactor wherein a relatively small amount of water is added directly to the pressure taps of the first reactor.

Abstract: A gas phase process for the production of an in situ polyethylene blend comprising contacting ethylene and at least one alpha-olefin comonomer having 3 to 8 carbon atoms with a magnesium/titanium based catalyst system including an activator and a cocatalyst in each of two fluidized bed reactors corrected in series, under polymerization conditions, with the provisos that:(a) the mixture of ethylene copolymer matrix and active catalyst formed in the first reactor in the series is transferred to the second reactor in the series;(b) other than the active catalyst referred to in proviso (a) and the cocatalyst referred to in proviso (f), no additional catalyst is introduced into the second reactor;(c) in the first reactor in which a relatively high molecular weight copolymer is made:(1) the alpha-olefin is present in a ratio of about 0.01 to about 0.4 mole of alpha-olefin per mole of ethylene; and(2) optionally, hydrogen is present in a ratio of about 0.001 to about 0.

Abstract: A propylene.ethylene block copolymer composition having a high stiffness and high-impact properties and its production process are provided,which composition is produced by using a specified Ziegler-Natta type catalyst;carrying out polymerization step (I) wherein homopolymerization of propylene is carried out by means of two or more polymerization vessels so as to afford 60 to 95% by weight based upon the total weight, and a specified range of the maximum value and the minimum value of the melt flow rates of the polymers obtained in the respective vessels; andcarrying out polymerization step (II) wherein propylene-ethylene random copolymerization is carried out by means of one or more polymerization vessels so as to afford 5 to 40% by weight based upon the total quantity,the ratio of the melt flow rate at the polymerization step (I) to the melt flow rate at the polymerization step (II) being made to fall within a specified range,whereby the resulting ethylene.

Abstract: A process comprising contacting ethylene and at least one alpha-olefin comonomer having 3 to 8 carbon atoms with a transition metal based catalyst system in two fluidized bed reactors connected in series, in the gas phase, under polymerization conditions, with the provisos that:(a) the first reactor is operated at a temperature at or above the dew point of the mixture of monomers, but no higher than about 5 degrees C. above said dew point;(b) the mixture of ethylene copolymer matrix and active catalyst formed in the first reactor in the series is transferred to the second reactor in the series;(c) other than the active catalyst referred to in proviso (b), no additional catalyst is introduced into the second reactor;(d) in the reactor in which a low melt index copolymer is made:(1) the alpha-olefin is present in a ratio of about 0.01 to about 0.4 mol of alpha-olefin per mol of ethylene; and(2) optionally, hydrogen is present in a ratio of about 0.001 to about 0.

Abstract: A reformed polypropylene resin composition having high degree of fluidity and excellent impact strength and rigidity, and further having a melt flow rate of from 50 to 150 g/10 min. and establishing a relationship between the melt flow rate (X) and the Izod impact strength (Y) which satisfies a relation Y.gtoreq.-4.7878 log X+13.8829. The reformed polypropylene resin composition is obtained by blending 0.01 to 0.2 parts by weight of an organic peroxide and 0.05 to 1 part by weight of a crosslinking agent per 100 parts by weight of a total of 50 to 90 parts by weight of a polypropylene having a melt flow rate at 230.degree. C. of 10 to 70 g/10 min, 0 to 25 parts by weight of an olefin copolymer rubber, and 5 to 40 parts by weight of an organic filler, and by melt-kneading the mixture by using a biaxial extruder maintaining a temperature of 120.degree. to 200.degree. in the preceding stage of the screw and a temperature of 180.degree. to 270.degree. C.

Abstract: A process for preparing linear copolyesters which contain omega-hydrocarboxylic acid units, from polyesters that contain at least 90 mol % polyethylene terephthalate units, as well as the usual amount of diethylene glycol units and possibly the known catalysts and stabilizers, includes adding to the already prepared polyester melt at least one compound of the group of lactones, optionally along with further additives but without additional catalysts in a system sealed off from gas exchange and at a higher pressure than the lactone vapor pressure in a proportion of up to 10 mol %, referred to the final melt, and mixed intensively with the melt. The resultant copolyesters, after a total dwell time of less than 30 minutes and a temperature in the range of 265.degree. to 310.degree. C.

Abstract: Multistage process for the polymerization of one or more olefins of the formula CH.sub.2 .dbd.CHR, in which R is hydrogen or an alkyl, cycloalkyl or aryl group having from 1 to 10 carbon atoms, comprising:(A) a first stage of polymerization, in which a first olefin polymer is prepared in the presence of titanium catalyst or vanadium catalyst;(B) a treatment stage in which the catalyst used previously is deactivated and in which a metallocene compound is supported on the olefin polymer produced in stage (A); and(C) a second stage of polymerization in which one or more olefins are polymerized in the presence of the product obtained from stage (B).

Abstract: High-flow propylene/ethylene copolymers which have a melt flow index of from 2 to 200 g/min under a load of 2.16 kg at 230.degree. C. and which may be produced from the gas phase by polymerization in two stages in an agitated fixed bed in the presence of hydrogen acting as chain stoppage regulator and using a Ziegler-Natta catalyst system comprising a titaniferous solid component which contains a magnesium compound on finely divided silicon oxide or on finely divided aluminum oxide or on a finely divided aluminum silicate having the empirical formula SiO.sub.2.aAl.sub.2 O.sub.3, where a stands for a value between 0.001 and 2, and an aluminum component, by means of a procedure comprisinga) a first polymerization stage in which propylene is polymerized under a pressure of from 20 to 40 bar and at a temperature of from 60.degree. to 90.degree. C.

Abstract: A stable partially polymerized syrup comprising dispersed rubber-like composite particles in a resin phase may be converted to a metastable syrup in which the rubber-like composite and resin phases are co-continuous by subjecting the stable syrup to high shear under pressure.

Abstract: A functionalised polymer, especially an ashless dispersant or a viscosity index improver dispersant, suitable for use as a lubricating or fuel oil additive, or as an intermediate for use in the manufacture of such an additive, is prepared from reactants in different phases by reacting the reactants in a reaction region defined by adjacent surfaces between which there is relative movement or in a thin film on a surface over which they move.

Abstract: A process for the production of an in situ particulate polyethylene blend comprising contacting a magnesium/titanium based catalyst system including a particulate precursor with one or more alpha-olefins in each of two or more reactors connected in series, in the gas phase, under polymerization conditions, with the provisos that:(a) the particulate precursor has a particle size distribution span of no greater than about 1.

Abstract: Multistage process for the polymerization of olefins CH.sub.2 .dbd.CHR, where R is hydrogen or an alkyl, cycloalkyl or aryl radical with 1-10 carbon atoms, comprising two stages of polymerization. In a first stage, in the presence of a titanium or a vanadium catalyst and working in one or more reactors, an olefinic polymer with particular values of porosity is prepared; in a second stage, in the presence of the said porous polymer and a metallocene compound and/or their reaction products, one or more olefins, that are equal to or different from those polymerized in the first stage, are polymerized in one or more reactors.

Abstract: In a process for preparing block copolymers of styrene or its equivalents on the one hand and of butadiene or its equivalents on the other hand by sequential anionic polymerization, in which a first monomer and the organometallic compound serving as initiator are first of all combined to form a reaction mixture and the reaction is continued until at least part of the first monomer has been consumed, and then at least one further monomer is added and is in each case partially or completely reacted, the polymerization is carried out continuously in a conventional manner in a tubular reactor, the reaction of in each case one monomer being carried out in each case in one reactor section and at least two reactor sections being separated by a mixing stretch.

Abstract: A method is provided for continuous mass polymerization of acrylonitrile-butadiene-styrene type thermoplastics. The method involves charging a liquid feed comprising a vinylidene aromatic monomer, an unsaturated vinyl nitrile monomer and a synthetic butadiene polymer dissolved therein into a grafting reactor to prereact the liquid mass to form grafted rubber continuous phase polymeric product. The product from the grafting reactor is then charged to a phase inversion reactor where free rigid copolymer in monomer is the only continuous phase, and where dispersed particles of grafted rubber with occluded rigid copolymer and monomer are immediately formed from the product of the grafting reactor. The second polymerization product, which is coming out from the phase inversion reactor, is then charged to a finishing reactor wherein the material is further polymerized to form a third polymerization product which then can be devolatilized to provide a final thermoplastic composition.

Abstract: The volume average diameter of relatively large rubber-like composite particles dispersed through out a continuous resin phase may be reduced by subjecting the syrup to a shear field. The application of a uniform shear field generator to the relatively large rubber-like composite particle syrup is particularly desirable since it gives a high degree of control over the size and distribution of the dispersed rubber-like composite phase. As a result it is possible to optimize the particle size distribution in an impact modified thermoplastic and obtain better or a better balance of properties.

Abstract: A process for continuously producing a linear lactide copolymer having a weight-average molecular weight of from 20,000 to 400,000 using a continuous reaction apparatus composed of three or more stirred flow reactors connected in series, which process comprises the steps of continuously feeding from 50 to 98 parts by weight of a lactide and from 2 to 50 parts by weight of a polymer having a hydroxyl group in a molten state or as dissolved in a solvent to the first reactor of said continuous reaction apparatus, and transferring the reaction mixture from said first reactor to the following reactors successively while maintaining the reaction pressure and the reaction temperature in every reactor in the range of from 1 to 5 atm. and of from 140.degree. to 210.degree. C., respectively, to conduct ring opening copolymerization. According to the process of the present invention, the production problems associated with conventional continuous production methods for lactide copolymers, i.e.

Abstract: A post inversion metastable syrup comprising a continuous or co-continuous rubber like composite phase and a discontinuous or co-continuous resin phase may be particulated by the application of a shear field to yield a stable syrup comprising a dispersed rubber-like composite phase and a continuous resin phase. The application of a uniform shear field to the post inversion metastable syrup is particularly desirable since it results in a high degree of control over the size and distribution of the dispersed rubber-like composite phase. As a result it is possible to optimize the particle size distribution in an impact modified thermoplastic and obtain better or a better balance of properties. The present invention also provides in cooperating arrangement reactors or devices to produce a post inversion metastable syrup, a device to subject the roetastable syrup to a shear field and a polymerization plant.

Abstract: Synthetic organic fibers containing finely divided, inorganic particles that have certain organic polymeric coatings have significantly less abrasiveness than do identical fibers containing such particles without any such polymeric coatings.

Abstract: A process for continuously preparing rubber modified styrene resins from styrene monomers and acrylonitryle monomers in the presence of a rubbery polymer in accordance with a continuous mass and/or solution polymerization method by the use of serial polymerization device comprising two or more reactors; said process comprising(1) a first step of feeding a polymeric materials to the first reactor to carry out the polymerization of monomers in a condition where the rubbery polymer is not inverted to the dispersed phase, and a second step of adding a polymeric materials to second reactors to carry out the polymerization of the monomers and to thus invert the rubbery polymer to the dispersed phase,(2) a ratio of the added materials to the materials used in the first step being in the range of from 10 to 220% by weight,whereby impact resistance and surface gloss can be remarkably improved.

Abstract: An advanced control method is disclosed for the polymerization of an alpha-olefin in a substantially horizontal, quench-cooled, stirred bed reactor.

Abstract: The present invention provides polymer polyols and a method for preparing polymer polyols which have (1) exceptional dispersion stability, especially at high styrene contents, and (2) substantially smaller particle sizes than polymer polyols having equivalent viscosity. In a preferred embodiment of the present invention, a first reaction product is obtained by feeding the following materials to a first continuous reactor in the presence of a free radical initiator or catalyst: (a) less than about 50 wt. % of a total monomer proportion or monomer mixture, preferably comprising styrene/acrylonitrile at a ratio preferably greater than about 50/50 wt. %; (b) at least about 50 wt. % of a total base polyol proportion; (c) a majority of a precursor stabilizer; and, (d) a polymer control agent (PCA).

Abstract: A process for manufacturing bimodal olefin polymers and copolymers having a ratio between low molecular weight fractions within the range of 40:60-70:30, by mixing under shear conditions 5-50 percent by weight of a low molecular weight unimodal polyolefin having a molecular weight (Mw) between 15,000-30,000, and 95-50 percent by weight of a bimodal polyolefin having a ratio between low molecular weight fractions and high molecular weight fractions within the range of 30:70-55:45. According to a preferred embodiment, there is used a multi-phase process including a loop reactor followed by a gas-phase reactor, wherein a part of the product coming out from the loop reactor is separated and combined with the bimodal product coming out from the gas-phase reactor.

Abstract: A bulk process is provided for making maleimide copolymers. The process involves reacting a monomer mixture comprising a maleimide monomer compound, a vinyl aromatic compound and a vinyl cyanide compound in a continuous stirred tank reactor, and then further reacting the material in a plug flow reactor to obtain a desired conversion level, and then devolatizing the product. The process provides enhanced oligomer control and enhanced levels of glass transition temperature and other properties. The maleimide copolymer obtained by the process may be further blended with impact modifiers to produce thermoplastic compositions which are useful for making molded articles such as automotive parts for under the hood applications, such as distributor caps.

Abstract: Polymer polyols prepared by a semi-batch process using a small amount of a seed polymer polyol are disclosed. The final polymer polyol has a broader particle size distribution as compared to an identically prepared polymer polyol prepared in the absence of the seed polymer polyol. The polymer polyols are suitable for use in producing polyurethanes, particularly polyurethane foams.

Abstract: A continuous process for producing a propylene-ethylene block copolymer having well-balanced properties of impact strength, stiffness, processability, etc. using a highly active catalyst, with a superior productivity is provided,which process comprisesa first polymerization step (I), carried out using a catalyst system consisting of [A] a solid catalyst component containing Ti, Mg, halogen and a polyvalent carboxylic acid ester as indispensable components, [B] an organoaluminum compound catalyst component and [C] an electron-donating compound,using two or more continuous polymerization vessels, andfeeding monomer(s) of ethylene/(ethylene+propylene) of 0 to 5% by weight, to carry out polymerization composed mainly of propylene, so as to give 60 to 95% of the total polymerized quantity;a continuous addition of a glycol compound (D) expressed by the formulaR.sup.1 --(OC.sub.m H.sub.2m).sub.n --OR.sup.2wherein m is an integer of 2 or more, n is an integer of 3 or more, R.sup.1 and R.sup.

Abstract: Graft copolymerized maleimide-modified, impact resistant monovinylidene aromatic copolymer compositions have substantially improved impact strength and fatigue resistance properties when the swelling index thereof is 12 or greater and when the numerical difference in maleimide monomer content as between the grafted copolymer and matrix copolymer portions thereof differ by no more than 9 percentage points from each other. Such compositions are conveniently prepared by mass, solution or mass/suspension graft copolymerization processes and by deferring the addition of at least about 30 percent of the maleimide monomer ingredient to a point in the process after (and preferably only shortly after) phase inversion of the dissolved impact modifying rubbery polymer ingredient.

Abstract: A process for producing polyethylene having a broad molecular weight distribution is provided, in which ethylene and optionally a comonomer are contacted in two reactors connected in series, one reactor containing a titanium-based catalyst and the other reactor containing a vanadium-based catalyst and a halohydrocarbon promoter, or alternatively, both reactors containing a mixed metal catalyst comprising both titanium and vanadium. In the latter case, the halohydrocarbon promoter is present in only one of the reactors to activate the vanadium sites of the catalyst and deactivate the titanium sites of the catalyst simultaneously.

Abstract: A process for producing a copolymer of propylene and other .alpha.-olefins in the presence of a catalyst comprising a titanium-containing solid catalyst component and an organoaluminum compound is disclosed. The process comprises (1) a first step in which propylene is homopolymerized or propylene and a minor proportion of other .alpha.-olefin are copolymerized to prepare polymer particles having a pore volume of from 0.15 to 0.30 cm.sup.3 /g, and (2) a second step in which propylene and other .alpha.-olefin are copolymerized in the presence of said polymer particles. The resulting propylene copolymer particles have improved fluidity and high bulk density.

Abstract: A method is provided for continuous mass polymerization of acrylonitrile-butadiene-styrene type thermoplastics. The method involves charging a liquid feed comprising a vinylidene aromatic monomer, an unsaturated vinyl nitrile monomer and a synthetic butadiene polymer dissolved therein into a grafting reactor to prereact the liquid mass to form grafted rubber continuous phase polymeric product. The product from the grafting reactor is then charged to a phase inversion reactor where free rigid copolymer in monomer is the only continuous phase, and where dispersed particles of grafted rubber with occluded rigid copolymer and monomer are immediately formed from the product of the grafting reactor. The second polymerization product, which is coming out from the phase inversion reactor, is then charged to a finishing reactor wherein the material is further polymerized to form a third polymerization product which then can be devolatilized to provide a final thermoplastic composition.

Abstract: A gas phase process for the production of a polyethylene blend comprising contacting ethylene and at least one alpha-olefin comonomer having 3 to 8 carbon atoms with a magnesium/titanium based catalyst system including an activator and a cocatalyst in each of two fluidized bed reactors connected in series, under polymerization conditions, with the provisos that:(a) the mixture of ethylene copolymer matrix and active catalyst formed in the first reactor in the series is transferred to the second reactor in the series;(b) other than the active catalyst referred to in proviso (a) and the cocatalyst referred to in proviso (e), no additional catalyst is introduced into the second reactor;(c) in the first reactor in which a low melt index copolymer is made:(1) the alpha-olefin is present in a ratio of about 0.01 to about 0.4 mole of alpha-olefin per mole of ethylene;(2) optionally, hydrogen is present in a ratio of about 0.001 to about 0.

Abstract: Process for the preparation of LLDPE with improved processability by gas phase polymerization performed in two or more reactors, wherein, whatever the order, in one of the reactors a mixture of ethylene and an alpha-olefin CH.sub.2 .dbd.CHR, where R is an alkyl having 1-10 carbon atoms, is polymerized to yield a copolymer containing up to about 20% by mole of the alpha-olefin, and in another reactor a mixture of propylene and an alpha-olefin CH.sub.2 .dbd.CHR', where R' is an alkyl radical having 2-10 carbon atoms, is polymerized to yield a copolymer containing from 5 to 40% by weight of said olefin, in an amount of 5-30% with respect to the total polymer weight and the polymer-catalyst system obtained in the first reactor is fed to the other reactors.

Abstract: A process for the continuous preparation of high-impact polystyrene-acrylonitrile (ABS) by free radical-initiated polymerization of a mixture of from 60 to 90% by weight of at least one vinylaromatic monomer and from 10 to 40% by weight of least one further ethylenically unsaturated monomer, in the presence of from 5 to 30% by weight, based on the sum of the monomers, of polybutadiene having a solution viscosity (5% strength by weight in styrene at 25.degree. C.) from 25 to 95 mPa.s and in the presence or absence of a solvent, in at least three consecutive reactors operated essentially without back-mixing, at from 50.degree. to 170.degree. C., phase inversion taking place in one of the reactors, involves carrying out the polymerization as far as phase inversion at 90.degree. C. or below and initiating the polymerization by free radicals from the decomposition of tert-butyl peresters whose half life period at 90.degree. C.

Abstract: Film having good blocking properties and low coefficient of friction is prepared without the presence of antiblock additives from certain thermoplastic ethylene interpolymer products. The thermoplastic ethylene interpolymer products have a density of about 0,935 g/ml or less, a melt flow ratio, I.sub.10/ I.sub.2, of at least about 8, and at least about 0.5 percent by weight of the interpolymer product has a weight average molecular weight of at least about 1,000,000 grams/mole. The interpolymer products are a blend or composite of ethylene polymers or copolymers and comprise at least a first interpolymer of ethylene with at least one alpha-olefin monomer. Preferably, the interpolymer products have a melt index, I.sub.2, of from about 0.1 to about 4 grams/10 minutes. The interpolymer products can be made using discrete polymer blends, or preferably, in a multiple reactor sequence. Blown film made from the interpolymer products is especially useful in grocery sack applications.

Abstract: A continuous method for the in-situ polymerization of plastic in an elastomeric material in a form suitable for reinforcing the elastomeric material is provided. The method comprises feeding elastomer and a monomer or monomer precursor of a reinforcing material into a mixing device, mixing the elastomer and the monomer or monomer precursor vigorously, initiating polymerization, and causing the monomers to continue to polymerize until the polymer solidifies when the melting point of the polymer produced exceeds the mixing temperature of the elastomer, terminating polymerization.

Abstract: The present invention provides polymer polyols and a method for preparing polymer polyols which have (1) exceptional dispersion stability, especially at high styrene contents, and (2) substantially smaller particle sizes than polymer polyols having equivalent viscosity. In a preferred embodiment of the present invention, a first reaction product is obtained by feeding the following materials to a first continuous reactor in the presence of a free radical initiator or catalyst: (a) less than about 50 wt % of a total monomer proportion or monomer mixture, preferably comprising styrene/acrylonitrile at a ratio preferably greater than about 50/50 wt %; (b) at least about 50 wt % of a total base polyol proportion; (c) a majority of a precursor stabilizer; and, (d) a polymer control agent (PCA).

Abstract: Rubber-modified styrene resins with excellent impact resistance are prepared by formulating a feed from a styrene-based monomer, or a mixture thereof with comonomers and high-viscosity rubber, an organic peroxide, and, if necessary, all inert organic solvent, preheating and continuously supplying the feed to one end of a plug flow type reactor equipped with an agitator, performing the preliminary polymerization to a conversion sufficiently high for the transformation of the rubber in the feed into particles while controlling the weight average particle diameter of the rubber particles to 0.8 to 5 .mu.m, withdrawing the prepolymerized feed from the other end of the reactor, and supplying it to a following plug flow type reactor for continuous enhancement of tile conversion.

Abstract: A process for producing a rubber-modified styrene-based resin. The process includes supplying a styrene-based monomer solution containing 5 to 20% by weight of a rubber component containing a styrene-butadiene-based block polymer rubber with a styrene content of 20 to 50% by weight to a first polymerization zone where initial polymerization is conducted to a conversion of 10 to 30%, and then supplying the resulting initial polymerization solution to a second polymerization zone where polymerization is conducted to a conversion of 30 to 70%, while at the same time phase inversion is caused, thereby controlling a rubber particle diameter to a range of 0.2 to 1.5 .mu.m and an area average rubber particle diameter/number average rubber particle diameter ratio (Ds/Dn) to not more than 2.5. The process results in ease of removal of polymerization heat, reduced power for agitation and does not require a high strength apparatus.

Abstract: In order to prepare thermoplastic molding materials from pulverulent polyphenylene ethers and aromatic vinyl polymers by melt extrusion, the pulverulent polyphenylene ether is first of all compacted and/or sintered under pressure and if necessary with the addition of heat, preferably under a pressure corresponding to a nip pressure of from 1 to 100 kN/cm, to form a porous compact. The compact is then fed in the form of agglomerates having a particle size of from about 0.5 mm to about 20 mm into an extruder or the like, mixed with the aromatic vinyl polymer and if desired further components, and melted. In this way the proportion of the fines in the polyphenylene ether is considerably reduced, with the result that there is virtually no further danger of dust explosions. Further advantages include improved ease of metering and reduced electrostatic charge of the agglomerates. The extruded molding materials have good mechanical properties and also high thermal stability.