Abstract: Catalytic solids based on titanium trichloride complex, usable for the stereospecific polymerisation of alpha-olefins, obtained by heat treatment, in the presence of a halogenated activating agent, of the liquid material resulting from bringing TiCl.sub.4, pretreated with an electron-donor compound, into contact with a composition (C) corresponding to the general formulaAlR.sub.p (Y).sub.q X.sub.3-(p+q)in whichR represents a hydrocarbon radical or a hydrogen atom;Y represents a group chosen from --OR', --SR' and --NR'R", in which R' and R" each represent a hydrocarbon radical or a hydrogen atom;X represents a halogen;p is an arbitrary number such that 0<p<3; andq is an arbitrary number such that 0<q<3;the sum (p+q) being such that 0<(p+q).ltoreq.3.These catalytic solids of controllable porosity permit the production of a wide range of propylene polymers, in particular the propylene and ethylene copolymers known as "block" copolymers.

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 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: 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: There are herein disclosed an olefin copolymer which comprises an olefin unit and a diolefin unit and in which a weight-average molecular weight is in the range of 200 to 800,000, the content of the diolefin unit is in the range of 0.002 to 30 mol%, and a ratio TUS/DOU between the total content of unsaturated groups observed in a molecular chain (TUS mol%) and the content of the diolefin unit (DOU mol%) is in the range of 0.001 to 200; an olefin graft copolymer obtained by the graft polymerization of this olefin copolymer and an olefin; a hydrogenated olefin copolymer and olefin graft copolymer thereof; and a process for preparing these copolymers.These olefin copolymers are excellent in molding/working properties and have a good thermal stability, transparency and uniformity. Therefore, they are useful as a high-performance VLDPE, LDPE, L-LDPE and HDPE, and further useful as a novel branched propylene polymer, a thermoplastic elastomer, a compatibilizing agent for other resins, and the like.

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: A process for producing an olefin polymer comprising polymerizing an olefin or olefins in the presence of a catalyst system, in which the catalyst system comprises of (A) a hydrocarbon-insoluble solid catalyst component obtained by treating a uniform hydrocarbon solution containing (a) an magnesium compound, e.g., a dialkoxymagnesium, (b) an titanium compound, e.g., a titanium tetraalkoxide, and (c) a polyalkyltitanate represented by formula (I): ##STR1## wherein R.sup.3 's, which may be the same or different, each represent an alkyl group, an aryl group, or a cycloalkyl group; and p represents an integer of from 2 to 20, with a halogenating agent and (B) an organoaluminum compound. The resulting olefin polymer has broad molecular weight distribution, high melt tension, and high melt elasticity and is freed of fish eye by kneading under ordinary conditions.

Abstract: There are disclosed a styrenic copolymer which comprises at least one structural unit represented by the general formula (I) ##STR1## and a structural unit represented by the general formula (II) ##STR2## or a structural unit represented by the general formula (IX) ##STR3## wherein the symbols are each as previously defined in the specification, the structural unit (II) or (IX) being contained in an amount of 0.01 to 99.9 mol %; and a process for the production of the above copolymer.The above styrenic copolymer has a high degree of syndiotactic configuration in the stereoregularity of the main chain of the structural unit (I) as well as adhesivity and compatibility with a resin of a different type.

Abstract: A graft block copolymer is comprised of a saturated olefinic backbone with pendent anionic polymer side chains. The polymer is produced by copolymerizing an .alpha.--olefin with a 1-alkenyl monomer containing a functional group to which an anionically polymerized polymer can be grafted to produce graft block copolymer, anionically polymerizing at least one anionically polymerizable monomer to form living polymer chains, and then grafting the living polymer chains onto the copolymer to form the graft block copolymer.

Abstract: A graft block copolymer is comprised of a completely saturated olefinic backbone with pendant anionic polymer side chains. The polymer is produced by copolymerizing an .alpha.-olefin with a monomer which contains a functional group which can be metallated so an anionic monomer can be polymerized therefrom, metallating the copolymer by reaction with metal alkyl or aryl compound and a metallation activator, and growing anionic polymer side chains from the copolymer backbone by reacting an anionically polymerized monomer with the metallated copolymer.

Abstract: A bimetallic catalyst produces broad or bimodal molecular weight distribution polyolefin resin whose composition depends on the ratio of the concentration of the two metals of the catalyst producing the HMW and LMW components. The bimetallic catalyst produces a broad/bimodal MWD resin whose HMW and LMW components depend on the relative productivity of each of the transition metal sites of the catalyst. Water and/or carbon dioxide are cofed to the polymerization reactor at levels necessary to modify the weight fractions of the HMW and LMW components, thus achieving a target molecular weight distribution, MWD. The invention allows the resin MWD to be adjusted in the reactor. The weight fraction of the high molecular weight component decreases with the addition of the water and or the carbon dioxide and the FI of the overall product increases with a decrease in the HMW component weight fraction in the product.

Abstract: A process for preparing propylene block copolymers, comprising a preceding polymerization step in which a crystalline homopolymer of propylene, or a propylene-ethylene copolymer containing 7 wt. % or less of ethylene is produced in the presence of a catalyst comprising the following components (A) and (B), and a succeeding polymerization step in which the polymerization is continued in the presence of at least part of the homopolymer or copolymer, and of the following component (C) further added to give a copolymer with a polymerization ratio (weight ratio) of propylene to ethylene of from 0/100 to 90/10; the polymerization amount at the preceding polymerization step being from 30 to 95 wt.

Abstract: The olefin polymer composition according to the invention comprises [I] an (.alpha.-olefin/polyene copolymer-containing polymer in an amount of 0.005 to 99 by weight, said .alpha.-olefin/polyene copolymer-containing polymer comprising (i) an .alpha.-olefin/polyene copolymer and (ii) a polyethylene, and [II] a polyethylene in an amount of 1 to 99.995% by weight. The olefin polymer composition comprising the .alpha.-olefin/polyene copolymer-containing polymer [I] and the olefin polymer [II] has a high melt tension and an excellent moldability in an inflation molding, and further it can be molded into a large sized container, etc. by means of a blow molding or the like.

Abstract: There are disclosed a styrenic copolymer which comprises at least one structural unit represented by the general formula (I) ##STR1## and a structural unit represented by the general formula (II) ##STR2## or a structural unit represented by the general formula (IX) ##STR3## wherein the symbols are each as previously defined in the specification, the structural unit (II) or (IX) being contained in an amount of 0.01 to 99.9 mol %; and a process for the production of the above copolymer.The above styrenic copolymer has a high degree of syndiotactic configuration in the stereoregularity of the main chain of the structural unit (I) as well as adhesivity and compatibility with a resin of a different type.

Abstract: A propylene block copolymer having a high rigidity and an excellent impact strength is produced by (1) first polymerizing propylene or a mixture of propylene and another ethylenically unsaturated hydrocarbon monomer in the presence of a catalyst comprising a Ti-containing solid component (A), an organic Al compound-containing component (B) and an alkoxyl silicon compound-containing component (C), and (2) second copolymerizing, in a gas phase, propylene and another ethylenically unsaturated hydrocarbon monomer in the presence of the first crystalline polymer of step (1) by re-using the catalyst of first polymerization, and in the presence of a saturated hydrocarbon with 6 or more carbon atoms, thereby forming an elastomeric fraction incorporated into the crystalline polymeric fraction.

Abstract: Ethylene is homopolymerized in the presence of a catalyst consisting essentially of a Group 3 metal complex, preferably a scandium complex, having a bridged ligand structure. Optionally polymer blends are prepared by combining the process with another polymerization process, either in series or in parallel.

Abstract: An olefin polymerization process is provided wherein an olefin chargestock is contacted with an organic compound polymerization initiator, a Lewis acid coinitiator and a pyridine compound such as 2,6-di-tert-butylpyridine to produce homopolymers, copolymers or block copolymers having a narrow molecular weight distribution.

Abstract: The olefin polymer composition according to the invention comprises [I] an .alpha.-olefin/polyene copolymer-containing polymer in an amount of 0.005 to 99 by weight, said .alpha.-olefin/polyene copolymer-containing polymer comprising (i) an .alpha.-olefin/polyene copolymer and (ii) a polypropylene, and [II] a polymer of .alpha.-olefin having 3 or more carbon atoms in an amount of 1 to 99.995% by weight. The olefin polymer composition comprising the .alpha.-olefin/polyene copolymer-containing polymer [I] and the olefin polymer [II] has a high melt tension and an excellent moldability in an inflation molding, and further it can be molded into a large sized container, etc. by means of a blow molding or the like.

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: Resurfacing surfaces of highways, roads, etc. to provide skid-resistant surface by preparing polymer concrete composition containing a curable polymer composition containing ethylenically unsaturated polymer having carbon-bonded carboxyl groups and/or hydroxyl groups and at least one reactive thickener comprising Group IIA metal oxide or hydroxide or a polyisocyanate; mixing the resulting mixture with aggregate; coating said surface with the resulting composition; compacting and shaping the resulting composition and curing the compacted, shaped composition on said surface.

Abstract: There are disclosed a styrenic block copolymer having a reduced viscosity of 0.01 to 20 dl/g (0.05 g/l in 1,2,4-trichlorobenzene at 135.degree. C.) which comprises highly syndiotactic styrenic-polymer segments and 10.sup.-4 to 10 mol % of heteroatom-containing styrenic polymer segments; a resin composition comprising the above styrenic block copolymer and a thermoplastic resin, an inorganic filler or an organic filler; a multi-layer material comprising at least one layer composed of the above styrenic block copolymer or the above resin composition; and a process for producing the above styrenic block copolymer which comprises polymerizing a styrenic monomer in the presence of a specific catalyst and adding a heteroatom-containing styrenic monomer to successively proceed with copolymerizaiton reaction.

Abstract: Particulates of a superabsorbent partially, neutralized acrylic polymer, e.g., polyacrylic acid, having a mean particle size ranging from 100 to 500 .mu.m, essentially monodisperse and essentially devoid of fines having a particle size of less than 100 .mu.m, having a nonuniformly surfaced spheroidal particle morphology and well suited for a variety of hygienic applications, are prepared by (i) polymerizing a suspension of an acrylic monomer charge I in an organic medium and producing a suspension of acrylic polymer gel particles, such acrylic monomer charge I having a degree of neutralization greater than that desired in the final superabsorbent polymer, (ii) next absorbing a second acrylic monomer charge II into the gel particles, such acrylic monomer charge II having a degree of neutralization less than that desired in the final superabsorbent polymer, and (iii) polymerizing in the gel particles the second acrylic monomer charge II.

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: Graft copolymers are disclosed which comprise an olefin borane-containing homopolymer or copolymer backbone polymer having radically polymerized polymeric segments chemically bonded as side chains or as a chain end. A borane-containing diene homopolymer or a copolymer of a diene and/or at least one alpha-olefin having from about 2 to 22 carbon atoms copolymerized with another monomer containing organoborane functional groups can be used as a backbone polymer to prepare the graft copolymers of the present invention. Under oxidation conditions, the borane group becomes the reaction site for the radical polymerization and copolymerization. Radical polymerizable monomers, such as methyl methacrylate, styrene, alpha-methylstyrene, acrylonitrile and the like, can be polymerized to yield high molecular weight graft copolymer. By this synthetic route, high graft efficiency is observed with only a very low concentration of homopolymer being produced.

Abstract: A catalyst system for the polymerization of alpha-olefins comprising a chromium-containing catalyst and an yttrium-containing catalyst wherein the yttrium-containing catalyst is represented by the formula (Cp.sub.2 YX.sub.x).sub.y.M.sub.z L.sub.n, wherein Cp is cyclopentadienyl or cyclopentadienyl substituted with alkyl or alkyl silyl radical or radicals, X is a halogen, M is an alkali metal, L is a suitable electron donor ligand, x is 1 or 2, y is 1 or 2, z is 0 or 1, and n is a number corresponding to the value needed to form a stable complex, with the proviso that when y is 2, z and n are 0 is provided. Also disclosed is a polymerization process employing such a catalyst system, and novel olefin polymers. Polymers thus produced exhibit high bulk density and a broad molecular weight distribution.

Abstract: A process for the production of block copolymers of ethylene and an .alpha.-olefin such as propylene by using an ionic catalyst system including a metallocene component and a component having a cation capable of donating a proton and a compatible non-coordinating anion. Novel block copolymers are produced.

Abstract: There are disclosed a styrenic block copolymer having a reduced viscosity of 0.01 to 20 dl/g (0.05 g/l in 1,2,4-trichlorobenzene at 135.degree. C.) which comprises highly syndiotactic styrenic-polymer segments and 10.sup.-4 to 10 mol % of heteroatom-containing styrenic polymer segments; a resin composition comprising the above styrenic block copolymer and a thermoplastic resin, an inorganic filler or an organic filler; a multi-layer material comprising at least one layer composed of the above styrenic block copolymer or the above resin composition; and a process for producing the above styrenic block copolymer which comprises polymerizing a styrenic monomer in the presence of a specific catalyst and adding a heteroatom-containing styrenic monomer to successively proceed with copolymerization reaction.

Abstract: The object of the present invention is to provide such a polyolefin that only the terminal of polypropylene or ethylene-propylene random copolymer is modified with a (meth)acrylic derivative unit to give a substantially monodipersed system. The feature thereof consists in such a polyolefin that the terminal of polypropylene or ethylene-propylene random copolymer obtained by living polymerization is modified with a (meth)acrylic derivative unit. As the (meth)acrylic derivative, there are used vinyl methacrylate, allyl methacrylate, trimethylsiloxyethyl methacrylate, 2-trimethylsiloxypropyl methacrylate, N, N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl methacrylate, glycidyl methacrylate, acrylic acid chloride and like.

Abstract: There are disclosed a graft copolymer formed by grafting a styrenic monomer onto a high polymer having double bonds in the side chain to constitute highly syndiotactic polystyrenic chain as the graft component, the graft copolymer having a content of graft component of 0.005 to 99% by weight and a reduced viscosity of 0.01 to 30 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135.degree. C. or a melt index of 0.001 to 500 g/10 minutes as measured at 300.degree. C. under a load of 2.16 kg; a process for efficiently producing the above graft copolymer using a catalyst comprising specific components; and a resin composition comprising the above graft copolymer, a highly syndiotactic styrenic polymer or other thermoplastic resin and, when necessary, an inorganic or organic filler. The above graft copolymer and resin composition are excellent in resistance to heat and chemicals, electrical properties, moldability, compatibility, impact resistance, etc.

Abstract: Disclosed is a propylene-ethylene/butene block copolymer, comprising a polybutene component block-copolymerized with a propylene-ethylene random copolymer component, or with a polypropylene component and a propylene-ethylene random copolymer component, the content of the polybutene component being 0.1 to 10% by weight, the total content of the propylene-ethylene random copolymer component and the polypropylene component being 99.9 to 90% by weight and the content of the polypropylene component being 0 to 30% by weight, wherein the propylene-ethylene random copolymer component is composed of a copolymer comprising 15 to 80 mole % of monomer units based on ethylene and 85 to 20 mole % of monomer units based on propylene, and said block copolymer is a powder having a high molecular weight.

Abstract: Propylene-ethylene copolymers are obtained by two-stage polymerization from the gaseous phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system that contains in addition to a titanium-containing solid component also an aluminum compound as co-catalyst, wherein as Ziegler-Natta catalyst system a system is used which, following the reaction of the titanium-containing solid component with the co-catalyst, is deactivated by reaction with carbon dioxide. The copolymers are used for producing fibers, films and moldings.

Abstract: A copolymer of an .alpha.-olefin with an aromatic diolefin such as divinylbenzene produced by means of Ziegler-Natta polymerization and having a vinylphenyl moiety is subjected to polymerization with an ethylenically unsaturated monomer by means of anion polymerization or free radical polymerization, whereby a graft-modified .alpha.-olefin copolymer is obtained.

Abstract: A method for producing a polyolefin is disclosed which comprises polymerizing an .alpha.-olefin in the presence of a catalyst composition comprising (A) a solid catalyst component prepared by contacting (a) a solid component comprising a magnesium alkoxide and/or a magnesium salt of a fatty acid supported on an inorganic oxide composed of at least one member selected from the group consisting of oxides of elements belonging to Groups II, III and IV of the periodic table and/or a composite inorganic oxide containing at least one member selected from the group consisting of oxides of elements belonging to Groups II, III and IV of the periodic table, the inorganic oxide or composite inorganic oxide having a surface hydroxide concentration of 3 .mu.mol/m.sup.2 or less, (b) an electron donating compound and (c) a titanium halide, (B) an organic metal compound, and (C) an electron donating compound.

Abstract: A propylene block copolymer having good flow properties and a very good low temperature impact strength is obtained in a high yield if a catalyst which consists of a chiral metallocene, containing a bridge, of the formula I ##STR1## and an aluminoxane is used for the polymerization of propylene and the comonomers.The polymerization is carried out in two stages, a crystalline propylene polymer being prepared in the first stage.

Abstract: A polymer dispersion of a star polymer dispersed in an organic liquid; wherein the star polymer has a crosslinked core having attached thereto at least three macromonomer arms; where(1) the core is formed of monomers having at least two ethylenically unsaturated double bonds which are crosslinked with each other and the core has at least 3 free radical polymerizable sites each of which are reacted with the macromonomer; and(2) the macromonomer that forms the arms of the star polymer is formed of ethylenically unsaturated monomers that have been polymerized by free radical polymerization in the presence of a free radical polymerization initiator and a catalytic chain transfer agent containing Co.sup.+2 to provide the macromonomer with a terminal ethylenically unsaturated group that is polymerized with the free radical polymerizable site on the core to form the star polymer.The process for making the star polymer and coating compositions that utilize the star polymer are also part of this invention.

Abstract: Polypropylene impact copolymer compositions demonstrate not only good low temperature properties, including impact strength, but also resistance to stress whitening when the numerical ratio of the intrinsic viscosity of the copolymer phase to the intrinsic viscosity of the homopolymer phase is near unity and ethylene contents of the copolymer phase are in the range of 38% to 60% by weight. The impact copolymer compositions are useful in the production of molded and extruded articles, shaped containers, and films having good clarity.

Abstract: Resurfacing surfaces of highways, roads, etc. to provide skid-resistant surface by preparing polymer concrete composition containing a curable polymer composition containing ethylenically unsaturated polymer having carbon-bonded carboxyl groups and/or hydroxyl groups and at least one reactive thickener comprising Group IIA metal oxide or hydroxide or a polyisocyanate; mixing the resulting mixture with aggregate; coating said surface with the resulting composition; compacting and shaping the resulting composition and curing the compacted, shaped composition on said surface.

Abstract: Disclosed is a composition of polybutene-1 comprised of a polymer resulting from preliminarily polymerization of a small amount of an .alpha.-olefin, which has an intrinsic viscosity [.eta.]p of 7 dl/gram or lower, as measured at 135.degree. C. in a decalin solution; and a homopolymer of butene-1 or a copolymer of butene-1 and 20% by weight of an .alpha.-olefin other than butene-1, the composition of polybutene-1 having an intrinisic viscosity [.eta.]t of 0.5-7.0 dl/gram, when measured at 135.degree. C. in a decalin solution, and satisfying the following relationship with respect to the intrinsic viscosity [.eta.]p:[.eta.]p.ltoreq.2.5.times.[.eta.]r. The composition provides resulting films with highly improved appearance and with a lesser number of gel and fish eyes.

Abstract: A polypropylene molding composition having syndiotactic polymer chains is obtained in a high yield by the copolymerization of propylene with ethylene or a 1-olefin of the formula R.sup.a --CH.dbd.CH--R.sup.b in the presence of a catalyst comprising a metallocene of the formula I ##STR1## in which M.sup.1 is titanium, zirconium, hafnium, vanadium, riobium or tantalum, and an aluminoxane. This molding composition has a very high molecular weight, a very narrow molecular-weight distribution and very high syndiotaxy. Shaped articles produced from the molding composition are distinguished by high transparency, flexibility, bear strength and excellent surface luster.

Abstract: The synthesis of poly(isobutylene-b-methyl vinyl ether) (PIB-b-PMeVE) by living carbocationic polymerization (LC.sym.Pzn) employing the sequential monomer addition (SMA) technique is described. The process starts by producing the living PIB.sym. block employing the 2-chloro-2,4,4-trimethylpentane (TMPC11/TiCl.sub.4 initiating system in the presence of the common ion salt tetra-n-butylammonium chloride (n-Bu.sub.4 NCl) in CH.sub.3 Cl/n-C.sub.6 H.sub.14 or CH.sub.2 Cl.sub.2 /n-C.sub.6 H.sub.14 mixed solvents at -80.degree. C. and continues by the addition of methyl vinyl ether (MeVE). The second living block forms only in the presence of excess TiCl.sub.4 suggesting that the species that starts the second block and subsequently sustains its growth is a MeVE.multidot.TiCl.sub.4 complex. The stoichiometry of this complex (1:1 or 1:2) is uncertain. The TiCl.sub.4 remains attached to the MeVE units after their incorporation into the diblock, however, it can be readily removed by water.

Abstract: There is disclosed a homoplymer of an alkenylsilane having a syndiotactic structure and a copolymer of the alkenylsilane and an .alpha.-olefin. The polymer and the copolymer can be prepared by subjecting the alkenylsilane or the alkenylsilane and the .alpha.-olefin to addition polymerization in the presence of a transition metal compound having asymmetirically interconnected ligands or preferably in the presence of the transition metal compound and aluminoxane. The polymer and the copolymer can be used as a nucleating agent for a crystalline polypropylene.

Abstract: Elastomeric polymers comprising polymerized alpha-olefins or conjugated alkadienes are produced by cationic polymerization in the presence of titanium tetrachloride and an electron pair donor selected from pyridine or a non-hindered alkylpyridine. The polymers have very narrow, mono-modal molecular weight distributions such a achived by anionic polymerization. Polymerization of each monomer is terminated prior to broadening of the molecular weight distribution which significantly detracts from polymer properties.

Abstract: Disclosed herein is a polypropylene resin composition of a high syndiotacticity comprising a substantial homopolymer of propylene, in which the ratio of the intensity of the peak attributable to the syndiotactic pentad bonds to the sum of the intensities of all the peaks attributable to the methyl groups in the spectrum of the methyl groups measured by .sup.13 C-NMR is 0.7 or more, and a copolymer of ethylene and propylene, and a preparation process thereof.

Abstract: The present invention relates to an improvement of the known Ziegler catalyst which comprises a combination of a titanium-containing component and an organoaluminum component, and the present invention is characterized by a specific titanium-containing component. Namely, this titanium-containing component is obtained by contacting a known titanium-containing component of the Ziegler type catalyst which comprises Ti, Mg and a halogen, with an alkoxyalkylsilane compound which is characterized in that at least one of the alkyl groups has a branched structure. This catalyst does not require a so-called external electron donor, and no reduction of the polymerization velocity caused by the use of the electron donor is entailed. When this catalyst is used, a propylene/ethylene block copolymer in which the molecular weight of the propylene/ethylene copolymer portion and/or the polyethylene portion is increased, that is, the rigidity and impact strength are increased, can be prepared.

Abstract: A catalyst component for producing highly crystalline olefin polymers without causing any operational problems and stably and affording therefrom a film having very few occurrence of voids and a superior transparency, and a process for producing the catalyst component, which catalyst component comprises a linear olefin-non-olefin block copolymer having at least one linear olefin block copolymer and at leaast one non-linear olefin polymer block and (a) a titanium trichloride composition or (b) titanium, magnesium, a halogen and an electron donor as components for a carrier, the content of the linear olefin polymer block being 0.1 to 49.5% by weight, the content of the non-linear olefin polymer block being 0.01 to 49.5% by weight, the ratio by weight of the linear olefin polymer block to the non-linear olefin polymer block being 2/98 to 98/2 and in the case of (a), the content of the titanium trichloride composition being 99.89 to 1.0% by weight.

Abstract: In a process for producing granular propylene block copolymers in two steps wherein a resinous homopolymer of propylene is produced in the first step and an elastomeric copolymer of propylene with ethylene is produced in the second step, the improvement which comprises conducting the second step in the presence of a granular propylene homopolymer added thereby to produce granular propylene copolymers endowed with an improved granulometric properties such as lowered tackiness and thus improving flowing characteristics.

Abstract: In a process for producing granular propylene block copolymers by Ziegler-Natta polymerization of an .alpha.-olefin wherein the Ziegler-Natta catalyst comprises a granular solid transition metal catalyst component and an organometal component in two steps wherein a resinous homopolymer of propylene is produced in the first step and an elastomeric copolymer of propylene with ethylene is produced in the second step, the improvement which comprises the use as the granular solid transition metal component of a mixture of the solid transition metal components, one made up substantially of particles of particle size of more than 5 microns and the other made up substantially of particles of particle size of 1 to 5 microns thereby to produce granular propylene copolymers endowed with an improved granulometric properties such as lowered tackiness and thus improved flowing characteristics. The component (B) is preferably produced from the particles for the component (A) by reducing the particle size of its particles.

Abstract: A conjugated diene compound prepolymer solution useful for the production of a vinyl aromatic compound high impact polymer material is produced by a process in which a prepolymerization mixture is prepared from 1 to 70 parts by weight of a conjugated diene compound and 30 to 99 parts by weight of a vinyl aromatic compound, and is prepolymerized at 0.degree. C. to 150.degree. C. in the presence of a prepolymerization catalyst which can cause the conjugated diene compound to be selectively polymerized but is substantially not effective for the polymerization of the vinyl aromatic compound to an extent such that the conjugated diene compound and the vinyl aromatic compound are prepolymerized at degrees of conversion of the conjugated diene compound at least 50% and 10% or less, respectively, and the resultant prepolymer solution is further polymerized by a radical or anionic polymerization method so that the vinyl aromatic compound is polymerized with the conjugated diene compound prepolymer.

Abstract: Block copolymers compose a polyisobutylene rubbery soft segment of M.sub.n of about 5,000 to above 500,000 and glassy hard segments of M.sub.n of about 5,000 or higher and usually about 10,000 to 35,000 or more, are made by preparing a living polymer block of the polyisobutylene and then polymerizing on said living polyisobutylene block the glassy hard segments by adding thereto an electron donor having a donor number of 15 to 50 and then adding and polymerizing the monomers for the glassy hard segments. The monomers for the glassy hard segments are styrene and its derivatives and indene and its derivatives and mixtures thereof.