Abstract: Syndiotactic terpolymers of styrene comprising repetitive units deriving from:a) 99.5-60% in moles of styrene; andb) 0.5-40% in moles of vinyltoluene having a weight average molecular weight of more than 20,000 and a stereoregularity of the syndiotactic type of more than 90%.

Abstract: There is disclosed a process for producing a styrenic polymer, especially, syndiotactic polystyrene, which comprises polymerizing a styrenic monomer by the use of (a) a transition metal compound, (b) a coordination complex compound comprising an anion in which a plurality of radicals are bonded to a metal and a cation or methylaluminoxane, (c) an alkylating agent (alkyl group-containing aluminum, magnesium or zinc compound) and (d) a reaction product between a straight-chain alkylaluminum having at least two carbon atoms and water (alkylaluminoxane). The above process is capable of simplifying the production process and producing high-performance styrenic polymer having a high degree of syndiotactic configuration in high catalytic activity without deteriorating the catalyst activity, increasing the amounts of residual metals in the objective polymer or leaving the decomposition products of the alkylaluminum therein, thereby curtailing the production cost of the objective polymer.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing vinylaromatic monomers, alone or mixed with at least one other monomer, in the presence of a catalytic system essentially consisting of:a) a complex of titanium or zirconium selected from those having general formula:MR.sub.1 R.sub.2 R.sub.3 R.sub.4, A.sub.1 MR.sub.1 R.sub.2 R.sub.3, A.sub.1 A.sub.2 MR.sub.1 R.sub.2 (I)b) a co-catalyst selected from an alkylalumoxane and a compound of boron having formula (II):BX.sub.1 X.sub.2 X.sub.3 (II)or one of its salts;c) a derivative of tin having general formula:SnR.sub.5 R.sub.6 R.sub.7 R.sub.

Abstract: In accordance with the present invention, there are provided ethylene copolymers composed of structural units (a) derived from ethylene and structural units (b) derived from .alpha.-olefin of 3.about.20 carbon atoms, said ethylene copolymers having?A! a density of 0.85.about.0.92 g/cm.sup.3,?B! an intrinsic viscosity ?.eta.! as measured in decalin at 135.degree. C. of 0.1.about.10 dl/g,?C! a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) as measured by GPC of 1.2.about.4, and?D! a ratio (MFR.sub.10 /MFR.sub.2) of MFR.sub.10 under a load of 10 kg to MFR.sub.2 under a load of 2.16 kg at 190.degree. C. of 8.about.50, and being narrow in molecular weight distribution and excellent in flowability.

Abstract: A process for preparing a cycloolefin copolymer by polymerization of at least one cycloolefin and at least one acyclic olefin in the presence of a catalyst which contains at least one cocatalyst and at least one metal-locene of the formula (I) ##STR1##

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: A catalyst component is disclosed for use in the homo- or copolymerization of olefinic hydrocarbons. The catalyst component is comprised of a first compound of the formula Me.sup.1 (OR.sup.1).sub.p R.sup.2.sub.q X.sup.1.sub.4-p-q and a second compound which is an organocyclic compound having two or more conjugated double bonds. A process is also disclosed for the production of hydrocarbon polymers in which the above catalyst component is combined with a modified or organoaluminum compound to form a catalyst composition capable of providing high molecular weight, wide distribution thereof and other desirable qualities in the polymer product.

Abstract: Process for the preparation of crystalline vinylaromatic polymers with a predominantly syndiotactic structure which comprises polymerizing the vinylaromatic monomers in the presence of a catalytic system consisting essentially of:a) a complex of titanium having the formula (I):Ti(OCONRR').sub.n (I)wherein R and R', the same or different, represent a C.sub.1 -C.sub.12 aliphatic radical or C.sub.6 -C.sub.12 aromatic radical whereas n is an integer equal to 3 or 4;b) a cocatalyst selected from aluminoxane and a compound of boron having formula (II):BX.sub.1 X.sub.2 X.sub.3 (II)wherein X.sub.1, X.sub.2 and X.sub.3, the same or different, represent a C.sub.1 -C.sub.20 perfluorinated hydrocarbon radical.

Abstract: In gas phase polymerizations and copolymerizations of ethylene, temperature controls the molecular weight, expressed as MI (wherein MI is measured according to ASTM D-1238 Condition E), of the resin product. Increase in polymerization temperature produces decrease in MI; whereas, decrease in polymerization temperature produces increase in MI.

Abstract: There is disclosed a process for producing a styrenic polymer, especially, syndiotactic polystyrene, which comprises polymerizing a styrenic monomer by the use of a (a) transition metal compound, a (b) coordination complex compound comprising an anion in which a plurality of racicals are bonded to a metal and a cation or a Lewis acid, a (c) alkylating agent (alkyl group-containing aluminum, magnesium or zinc compound) and a (d) reaction product between a straight-chain alkylaluminum having at least two carbon atoms and water (alkylaluminoxane). The above process is capable of simplifying the production process and producing high-performance styrenic polymer having a high degree of syndiotactic configuration in high catalytic activity without deteriorating the catalyst activity, increasing the amounts of residual metals in the objective polymer or leaving the decomposition products of the alkylaluminum therein, thereby curtailing the production cost of the objective polymer.

Abstract: A film including semi-crystalline cycloolefin copolymers which have a content of catalyst residues of <100 ppm and their use as capacitor films, reproduction films, film keyboards and film switches, substrates for liquid crystal displays and packaging films.

Abstract: In accordance with the present invention, there are provided ethylene copolymers composed of structural units (a) derived from ethylene and structural units (b) derived from .alpha.-olefin of 3.about.20 carbon atoms, said ethylene copolymers having[A] density of 0.85.about.0.92 g/cm.sup.3,[B] an intrinsic viscosity [.eta.] as measured in decalin at 135.degree. C. of 0.1.about.10 dl/g,[C] a ratio (Mw/Mn) of a weight average molecular weight (Mw) to a number average molecular weight (Mn) as measured by GPC of 1.2.about.4, and[D] a ratio (MFR.sub.10 /MFR.sub.2) of MFR.sub.10 under a load of 10 kg to MFR.sub.2 under a load of 2.16 kg at 190.degree. C. of 8.about.50, and being narrow in molecular weight distribution and excellent in flowability.

Abstract: A process for preparing syndiotactic vinylidene aromatic polymers comprising contacting one or more vinylidene aromatic monomers with a catalyst comprising a Group 4 metal complex in the +3 oxidation state and a polyalkylaluminoxane cocatalyst.

Abstract: Low density ethylene copolymers are obtainable by adding an aromatic hydrocarbon solution of a catalyst system, containing, as active components, metallocene complexes of metals of subgroups IV and V of the Periodic Table and oligomeric alumina compounds, to a mixture containing ethylene, comonomers and aliphatic hydrocarbons.

Abstract: A catalyst for production of 1,4-polybutadiene which comprisesas the catalyst component (A) a transition metal compound represented by the formula M(R).sub.l (OR').sub.m X.sub.n-(l+m), wherein M denotes a transition metal atom, R and R' each denote a hydrocarbon group of 1-20 carbon atoms, X denotes a halogen atom, and l, m and n denote numerals satisfying the equations l.gtoreq.0, m.gtoreq.0 and n-(l+m).gtoreq.0, n corresponding to the valence of the transition metal,as the catalyst component (B) an organoaluminum compound represented by the formula AlR.sup.1.sub.a X'.sub.3-a, wherein R.sup.1 denotes a hydrocarbon group of 1-20 carbon atoms, X denotes a halogen atom, and a denotes a numeral satisfying the equation 1.gtoreq.a.gtoreq.3, or an aluminoxane obtained by the reaction of said organoaluminum compound with water, andas the catalyst component (C) an organic compound having at least two hydroxyl groups.

Abstract: Polymers of polycyclic olefins such as, for example, norbornene or tetracyclododecene, or copolymers of polycyclic olefins with cycloolefins and/or 1-olefins with a very narrow molecular weight distribution are obtained without ring opening by a polymerization in which a catalyst which is composed of an aluminoxane and of a stereorigid, chiral metallocene compound of an element of groups IVb to VIb is used, and in which the reaction is stopped at a time when the molecular weight distribution Mw/Mn of the polymer formed is <2.

Abstract: A film of a linear low density copolymer of ethylene (LLDPE) having excellent processability, optical properties and impact strength, which exhibits a density of at least 0.900.

Abstract: There are disclosed a catalyst well suited for producing a styrenic polymer having a high degree of syndiotactic configuration which comprises a transition-metal compound such as pentamethylcyclopentadienyltrimethyltitanium and a coordination complex compound comprising an anion in which a plurality of radicals are bonded to a metal and a quaternary ammonium salt, the compound being exemplified by orthocyano-N-methylpyridinium tetra(pentafluorophenyl)borate, or comprises an alkylating agent such as triisobutylaluminum in addition to the above two compounds; and a process for producing a styrenic polymer having a high degree of syndiotactic configuration by polymerizing a styrenic monomer using the aforementioned catalyst. Consequently, a styrenic polymer having a high degree of syndiotactic configuration can be produced effectively without the use of an expensive aluminoxane required in a large amount if used.

Abstract: A styrene copolymer which comprises a styrene repeating unit (a) represented by the general formula (I): ##STR1## and an acrylonitrile repeating unit (b) represented by the general formula (II-(b)): ##STR2## unsaturated carboxylic acid or its ester repeating unit (c) represented by the general formula (II-(c)): ##STR3## or maleimide or N-substituted maleimide (d) represented by the general formula (II-(d)): ##STR4## (in the formula, symbols are the same as defined in the specification) wherein stereoregularity of the styrene repeating unit (a) chain is a high degree of syndiotactic configuration is disclosed.

Abstract: A process for the polymerization of actylenically unsaturated compounds by contacting the monomer(s) under polymerization conditions with a catalyst system comprising:a) a source of cations of one or more Group VIII metals;b) a bidentate ligand containing phosphorus, arsenic and/or antimony; andc) a source of anions.

Abstract: A catalyst for production of 1,4-polybutadiene which comprisesas the catalyst component (A) a transition metal compound represented by the formula M(R)l(OR')m X.sub.n-(l+m), wherein M denotes a transition metal atom, R and R' each denote a hydrocarbon group of 1-20 carbon atoms, X denotes a halogen atom, and l, m and n denote numerals satisfying the equations l.gtoreq.0, m.gtoreq.0 and n-(l+m).gtoreq.0, n corresponding to the valence of the transition metal,as the catalyst component (B) an organoaluminum compound represented by the formula AlR.sup.1.sub.a X'.sub.3-a, wherein R.sup.1 denotes a hydrocarbon group of 1-20 carbon atoms, X denotes a halogen atom, and a denotes a numeral satisfying the equation 1.ltoreq.a.ltoreq.3, or an aluminoxane obtained by the reaction of said organoaluminum compound with water, andas the catalyst component (C) an organic compound having at least two hydroxyl groups.

Abstract: Disclosed is a process for producing a styrene polymer having a syndiotactic configuration and a wide molecular weight distribution, which is characterized by using as catalyst (a) two or more kinds of titanium compounds and (b) alkylaluminoxane, in the polymerization of styrene monomers.According to the process of the present invention, a styrene polymer which is excellent in physical properties such as heat resistance because of a high syndiotacticity, and also has a wide molecular weight distribution can be obtained. These styrene polymers can be suitably used as materials for various moldings including hollow molding, sheet molding, and film molding.

Abstract: A process is provided for preparing butadiene-styrene copolymers having cis-1,4 configuration of at least 80% of butadiene units, bound styrene contents of 2 to 55% and no homopolystyrene. The copolymers are prepared with a new catalyst system having high polymerization activity. The process involves carrying out polymerization of butadiene monomer and styrene monomer in the presence of the new catalyst system which is comprised of a nickel compound and an alkylaluminoxane compound.

Abstract: Polyolefin rubber which is an ethylene/propylene and/or 1-butene copolymer, which has a melt index of 0.3 to 15 dg/min and a relative density of 0.860 to 0.885, comprising 74-91 mol % of units derived from ethylene and 9-26 mol % of units derived from propylene and/or from 1-butene, characterised by a crystalline melting point J of 100.degree. to 125.degree. C. The process for obtaining this rubber consists in copolymerising, at a temperature of 150.degree.-300.degree. C. and at a pressure of 400-2000 bars, a gas stream containing 15-42% by vol. of ethylene and 58-85% by vol. of propylene and/or 1-butene, in the presence of a Ziegler-type catalyst system comprising at least one compound of a transition metal of groups IVB, VB, VIB and VIII of the Periodic Classification, and at least one organoaluminium compound and, if appropriate, in the presence of at least one chain transfer agent.

Abstract: The present invention relates to a novel catalyst used for homopolymerization of an olefin of 2 or more carbon atoms or for copolymerization of two or more olefins of 2 or more carbon atoms, as well as to a process for producing an olefin polymer using said catalyst. High molecular olefin polymers can be produced at a high yield, by homopolymerizing an olefin or copolymerizing olefins using a catalyst system consisting of a transition metal compound of the general formula M(R).sub.l (OR').sub.m X.sub.n-(l+m) and an aluminoxane or a catalyst system comprising a transition metal compound of the general formula M(R).sub.l (OR').sub.m X.sub.n-(l+m), an aluminoxane and an organic compound having at least 2 hydroxyl groups.

Abstract: The present invention relates to a process for copolymerizing ethylene and .alpha.-olefin, or ethylene, .alpha.-olefin, and an unconjugated diene, in the presence of a catalyst in which at least one kind of transition metal compound, such as a V, Zr, or Hf compound, and an organic aluminum compound, are supported, and with the coexistence of a polysiloxane compound. By the process of the present invention fouling can be prevented when an ethylene-based copolymer is industrially prepared. Thus a continuous operation is made possible.

Abstract: A styrene copolymer which comprises a styrene repeating unit (a) represented by the general formula (I): ##STR1## and an acrylonitrile repeating unit (b) represented by the general formula (II-(b)): ##STR2## an unsaturated carboxylic acid or its ester repeating unit (c) represented by the general formula (II-(c)): ##STR3## or a maleimide or N-substituted maleimide (d) represented by the general formula (II-(d)): ##STR4## (in the formula, symbols are the same as defined in the specification) wherein stereoregularity of the styrene repeating unit (a) chain is a high degree of syndiotactic configuration is disclosed.

Abstract: Highly crystalline high melting 1,5-hexadiene cyclopolymers are prepared by carrying out the polymerization in the presence of a catalyst comprising a specific Zr or Hf metallocene compound and specific alumoxane compounds.

Abstract: A novel styrene copolymer comprising a styrene repeating unit (a) represented by the general formula: ##STR1## (wherein R.sup.1 is a hydrogen atom or a hydrocarbon group having not more than 20 carbon atoms; n is an integer of 1 to 3 and when n is 2 or 3, R.sup.1 s may be the same or different) and olefin repeating unit (b) represented by the general formula: ##STR2## (wherein R.sup.2 is a hydrogen atom or a saturated hydrocarbon group having not more than 20 carbon atoms) or diene repeating unit, which contains 0.1 to 99.9 wt. % of said olefin repeating unit (b) or diene repeating unit (c) wherein intrinsic viscosity measured in 1,2,4-trichlorobenzene at 135.degree. C. is 0.07 to 20 dl/g and the stereoregularity of the styrene repeating unit chain is a high degree of syndiotactic configuration. This styrene copolymer is excellent in heat resistance and chemical resistance, and further it can be injection molded at low temperature, and has good compatibility with other resine and the like.

Abstract: The present invention aims at providing an olefin polymerization catalyst comprising, as a component, a transition metal compound having two ligands such as .beta.-diketone, etc. coordinated, and having excellent properties as a polymerization catalyst in the polymerization of olefins including styrene compounds. This olefin polymerization catalyst comprises:(a) a transition metal compound represented by the general formula, ##STR1## wherein M represents titanium, zirconium, hafnium or vanadium, Y.sup.1 and Y.sup.2 each represent, same or different, halogen atoms or alkyl groups containing 1 to 10 carbon atoms and R.sup.1, R.sup.2 and R.sup.3 each represent hydrogen atoms or hydrocarbon groups containing 1 to 10 carbon atoms, at least one of which is a hydrogen atom but all of which must not be hydrogen atoms, and(b) an organoaluminum compound, in particular, aluminoxane.

Abstract: Styrene copolymers having a repeating unit (I) represented by the general formula: ##STR1## and a repeating unit (II) represented by the general formula: ##STR2## (wherein all the symbols are as defined in the appended claims), and having the stereoregularity that is mainly syndiotactic, and cross-linked styrene copolymers obtained by cross-linking the above styrene copolymers. The styrene copolymers are reactive resins (heat-sensitive resins and radiation-sensitive resins) and are excellent in heat resistance and chemical resistance. The cross-linked styrene copolymers are excellent in heat resistance, chemical resistance and mechanical strength.

Abstract: Styrene homo-or-co- polymers, the stereoregularity of which is mainly syndiotactic are disclosed, having repeating unit or two or more different repeating units defined by a general formula (I): ##STR1## wherein each R may be the same or different. And a method of preparation of syndiotactic copolymers wherein there are two different repeating units represented by formula (I); wherein the polymerization is carried out with a catalyst comprising (a) a titanium compound and (b) a contact product of an organoaluminum compound and a condensing agent such as water.

Abstract: This invention pertains to the use of a novel cocatalyst in ring opening polymerization of a cycloolefin containing a norbornene moiety in conjunction with a metathesis catalyst, said cocatalyst is selected from aluminum-siloxalanes, aluminum-stannoxalanes, aluminum-germoxalanes, aluminum-plumboxalanes, dialuminoxanes, and mixtures thereof.

Abstract: A process for the production of primarily syndiotactic vinyl aromatic polymers by polymerizing or copolymerizing vinyl aromatic monomers such as styrene or styrene derivatives in the presence of a catalyst system comprising the product of the reaction between:a) a compound of a transition metal (M) different from titanium and containing at least a bond M-O, M-C, M-N, M-P, M-S or M-halogen, andb) an organoaluminum compound containing at least an oxygen atom bound to the aluminum atom or bound between two aluminum atoms.Compound a) can be used as such or may be supported on a suitable carrier.

Abstract: A process for producing an ethylene copolymer, which comprises contacting ethylene and an .alpha.-olefin having 3-20 carbon atoms such as hexene with a catalyst comprising the following components (A) and (B):Component (A)a solid catalyst component for a Ziegler type catalyst which is obtained by contacting a magnesium halide such as MgCl.sub.2, a titanium halide such as TiCl.sub.3 and tetrahydrofuran and has a molar ratio of tetrahydrofuran/titanium in the range of 3-20; andComponent (B)an alumoxane having a structure of ##STR1## with an average polymerization degree m in the range of 3-50 and having a hydrocarbyl group R.sup.3 of 1-10 carbon atoms such as hexaisobutyltetraalumoxane where R.sup.3 is isobutyl and m is 4.

Abstract: A catalyst system for the polymerization of olefins is disclosed which comprises a metallocene component, for example, organometallic coordination compounds of a Group IVB or Group VB hydrolysis products comprising methane and C.sub.2 or higher alkanes, such as isobutane, n-butane or n-hexane.

Abstract: The invention is a catalyst system including a Group IVB, VB or VIB transition metal hydrocarbyloxide component and an alumoxane component which may be employed in liquid, slurry or bulk phase reactors to polymerize ethylene and .alpha.-olefins to produce a high molecular weight, narrow molecular weight distribution homo- and co-polymer.

Abstract: Disclosed is a process for drying aluminoxane, which comprises drying a viscous solution containing aluminoxane, while applying a shearing force sufficient to keep said viscous solution in polydispersive state, so as to make the solution to be a solid-state polydispersoid. Also disclosed is a process for producing a polymer which comprises polymerizing a polymerizable monomer, using the aluminoxane obtained by the process of the present invention.According to the process of the present invention, aluminoxane in uniform powder which is easy to treat can be efficiently obtained in an industrial scale, and polymers can be produced at high efficiency.

Abstract: This invention relates to an oligomerization catalyst comprising a zirconocene and one or more alkyl aluminoxanes wherein the alkyl is selected from methyl, ethyl and mixtures thereof and the ratio of equivalents of methyl to ethyl in the product ranges from about 4 to about 0.25 and wherein the atom ratio of aluminum to zirconium ranges from about 1 to about 100. It further relates to the method for preparing the catalyst and the use of the catalyst in an oligomerization process. The catalyst is particularly suited for the oligomerization of ethylene.

Abstract: A process for producing a styrene-based polymer having a high syndiotactic configuration, which comprises polymerizing a styrene-based monomer with addition of catalyst in such amounts that the conversion at 30 minutes after the polymerization starts becomes 2 to 50%, and then continuing the polymerization with additions of the catalyst when the conversion exceeds 10%.According to the process, the productivity can be improved while easily attaining safe running of the reactor and successful controlling of reaction heat.

Abstract: Disclosed is a process for producing a styrene-based polymer by contacting a styrene-type monomer with alkylaluminoxane previously, adding a transition metal compound and then polymerizing of the styrene-type monomer.By using the process of the present invention, polymerization of a styrene-type monomer can be carried out with a high catalytic activity, and a styrene-based polymer having high syndiotacticity can be obtained with high efficiency.The sytrene-based polymer having a high degree of syndiotactic configuration of this invention has various excellent physical properties such as heat resistance and chemical resistance, and can be effectively and widely utilized for various applications.

Abstract: A process for production of styrene polymers is disclosed, comprising polymerizing styrene monomers by the use of a catalyst comprising (a) a titanium compound and (b) a contact product of an organoaluminum compound and a condensing agent, and further in the presence of hydrogen. The styrene polymers produced by the present process have a stereo structure that substituent groups are mainly in the syndiotactic configuration. Thus the styrene polymers have high heat resistance and high solvent resistance as compared with atactic polystyrene commonly used and are useful as materials for production of articles for which high heat resistance and high solvent resistance are required.

Abstract: A process for producing styrene-based polymers having mainly syndiotactic configuration in the presence of a catalyst comprising (A) a titanium compound and (B) a contact product of a methyl group-containing organoaluminum compound and water, wherein the contact product (B) has a high magnetic field component of not more than 50% in the methyl proton signal region due to an aluminum-methyl group (Al--CH.sub.3) bond as determined by the proton nuclear magnetic resonance absorption method.According to this process, styrene-based polymers having mainly syndiotactic configuration can be efficiently and economically produced.

Abstract: Methylaluminoxane can be formed by the reaction of a tetraalkyldialuminoxane containing C.sub.2 or higher alkyl groups with trimethylaluminum with the trimethylaluminum being present in an amount which is not present in stoichiometric excess. Another embodiment of the present invention involves the synthesis of the methylaluminoxane by reaction of a trialkylaluminum compound or a tetraalkyldialuminoxane containing C.sub.2 or higher alkyl groups with water to form a polyalkylaluminoxane which is then reacted with trimethylaluminum. A third embodiment of the present invention involves the synthesis of the methylaluminoxane by reaction of the aforementioned polyalkylaluminoxane with trimethylaluminum and then with water.

Abstract: The present invention provides a method for producing addition copolymers of ethylene and cycloolefin monomers of the norbornene-type, such as norbornene and tetracyclododecene. Copolymers having a uniform structure with uniform glass transition temperature values are provided by performing the copolymerization reaction in bulk with a catalyst system soluble in the cycloolefin monomers.

Abstract: Polymers of vinyl aromatic monomers having a high degree of syndiotacticity are prepared by contacting with a catalyst comprising a zirconium (IV) complex and polymethylaluminoxane under polymerization conditions.

Abstract: Polyacetylene having an apparent density at 20.degree. C. greater than 0.6 g/ccm and a surface area below 60 m.sup.2 /g is prepared by polymerizing gaseous acetylene in the presence of a catalytic system consisting of:(a) an oxygenized compound of Ti or V, containing at least one metal-oxygen bond;(b) an organometallic compound of aluminum containing at least one hetero-atom, of the formula: ##STR1## wherein: ##STR2## while R=a hydrocarbon radical with 1-18 carbon atoms, and where R'.dbd.R, or halogen or alcoxyl.

Abstract: In the polymerization of propylene and other higher 1-olefins, polymers which have a high degree of isotacticity and a narrow distribution of molecular weight are obtained in the presence of a catalyst system composed of a zirconium compound which is stereo-rigid and chiral and a linear or cyclic aluminoxane. In addition, the catalyst system is exceptionally active.

Abstract: A solution process, and a catalyst therefor, for the preparation of high molecular weight polymers of alph-olefins viz. homopolymers of ethylene and copolymers of ethylene and C.sub.3 -C.sub.12 alpha-olefins, is disclosed. The process is operated under solution polymerization conditions at 105.degree.-320.degree.. The catalyst is obtained from titanium tetrahalides, vanadium oxytrihalides and organoaluminum compounds, in which an admixture of catalyst components is heat-treated at 150.degree.-320.degree. C., and activated with an aluminoxane. The catalyst has good activity and the polymer obtained has improved color.

Abstract: A process is provided for the polymerization of olefins in the gas phase wherein olefins are contacted with a catalyst system consisting of an active solid hydrocarbon having been prepared by forming a pulverulent composition by mixing a transition metal component, a porous organic or inorganic solid support and an organometallic compound of the organo-Al, organo-Mg or organo-Zn type, and polymerizing a controlled amount of one or more C.sub.2 to C.sub.12 olefins in the gas phase in contact with the pulverulent composition with a specific hourly conversion of the olefins to produce the active solid hydrocarbon.