Abstract: Components of bimetallic catalysts for the polymerization of olefins comprising a compound of a transition metal M selected from Ti, V, Zr and Hf containing at least one M-&pgr;bond, a compound of Ti or V not containing metal-&pgr; bonds and a support comprising a magnesium halide. The catalysts obtained from the components of the invention are particularly suitable for gas-phase polymerization processes.

Abstract: Process for the manufacture of a composition comprising ethylene polymers, in at least two polymerization reactors connected in series, according to which, in a first reactor, from 30 to 70% by weight with respect to the total weight of the composition of an ethylene homopolymer (A) having a melt flow index MI2 of 5 to 1000 g/10 min is formed and, in a subsequent reactor, from 30 to 70% by weight with respect to the total weight of the composition of a copolymer of ethylene and of hexene (B) having a melt flow index MI5 of 0.01 to 2 g/10 min is formed. The compositions obtained by this process exhibit a good compromise between the processing properties and the mechanical properties, which renders them capable of being used in the manufacture of articles shaped by extrusion and extrusion blow-molding, such as films and pipes.

Abstract: Catalyst compositions and methods, useful in polymerization processes, utilizing at least two metal compounds are disclosed. At least one of the metal compounds is a Group 15 containing metal compound and the other metal compound is preferably a bulky ligand metallocene-type catalyst. The invention also discloses a new polyolefin, generally polyethylene, particularly a multimodal polymer and more specifically, a bimodal polymer, and its use in various end-use applications such as film, molding and pipe.

Abstract: A catalyst composition comprises at least two different polymerization catalysts of which a) at least one is a polymerization catalyst based on an early transition metal component and b) at least one is a polymerization catalyst based on a late transition metal component.

Abstract: This invention relates to a process to polymerize olefins comprising reacting olefins with a combined catalyst system comprising a hydrogen generating olefin polymerization catalyst and from 10 ppm to 10 weight % of at least one hydrogen consuming olefin polymerization catalyst system, based upon the weight of the total catalyst present, not including any activators or supports.

Abstract: A modified particles obtained by contacting particles(a) with a metal compound(b) selected from the group consisting of compounds of the Group VI, VII, XIV metal elements and compounds of the lanthanide series, and contacting the particles with a compound(c) having a functional group containing active hydrogen or a non-proton donative Lewis basic functional group and an electron-withdrawing group; a carrier composed of the modified particles; a catalyst component for olefin polymerization composed of said modified particles; a catalyst for olefin polymerization obtained by contacting the modified particles(A) and a transition metal compound(B), or further an organometallic compound(C); and a process for producing an olefin polymer with the catalyst.

Abstract: A conjugated diene polymer is obtained by using a specified catalyst system consisting of components (a)-(d) and indicating a high polymerization activity to a conjugated diene compound. Further, a modified conjugated diene polymer is obtained by reacting with at least one specified compound selected from the group consisting of components (e)-(j).

Abstract: The present invention relates to a process for the polymerization of monomers utilizing a bulky ligand hafnium transition metal metallocene-type catalyst compound, to the catalyst compound itself and to the catalyst compound in combination with an activator. The invention is also directed to an ethylene copolymer composition produced by using the bulky ligand hafnium metallocene-type catalysts of the invention, in particular a single reactor polymerization process. The hafnocene compound comprises at least one ligand substituted with at least one linear or iso alkyl substituent of at least 3 carbon atoms, and the catalyst system may comprise a mixture of two or more such hafnocenes.

Abstract: The invention relates to metallocenes of formula (I), in which M is a metal from the Ti, Zr, Hf, V, Nb, Ta group or an element from the lanthanide group, X1 and X2 stand for an alkyl-, aryl-, alkenyl-, arylalkyl-, alkylaryl- or arylalkenyl group and L1 and L2 are hydrocarbon capable of forming a sandwich structure with M. R stands for C, Si, Ge or Sn, A and B are ferrocenyl-substituted radicals, or B is optionally a radical X1 of X2. The metallocenes are preferably used as catalysts in the polymerization of olefins.

Abstract: A high molecular weight polyethylene prepared by preliminary polymerization is added at the time of main polymerization of an olefin, for example, propylene, to prepare an olefin (co)polymer composition comprising the above high molecular weight polyethylene finely dispersed as fine particles in the polyolefin, such as polypropylene, and a cross-linked structure is formed in the olefin (co)polymer composition. This process can provide a modified olefin (co)polymer composition improved in the strength in a molten state in terms of melt tension or the like and in crystallization temperature and excellent in moldability such as high-speed producibility, and a molded modified olefin (co)polymer composition excellent in properties such as heat resistance and rigidity.

Abstract: A catalyst system suitable for the polymerization of olefins comprising an olefin polymerization catalyst and an activator comprising the reaction product of (i) an aluminoxane or (ii) the reaction product of an alkylaluminum and water with a silicon-containing compound, for example diphenylsilane diol. Preferred catalysts are metallocene complexes. The activators provide an alternative to the traditional use of aluminoxanes alone.

Abstract: Process for the manufacture of a composition comprising ethylene polymers, in at least two polymerization reactors connected in series, according to which, in a first reactor, from 30 to 70% by weight with respect to the total weight of the composition of an ethylene homopolymer (A) having a melt flow index MI2 of 5 to 1000 g/10 min is formed and, in a subsequent reactor, from 30 to 70% by weight with respect to the total weight of the composition of a copolymer of ethylene and of hexene (B) having a melt flow index MI5 of 0.01 to 2 g/10 min is formed. The compositions obtained by this process exhibit a good compromise between the processing properties and the mechanical properties, which renders them capable of being used in the manufacture of articles shaped by extrusion and extrusion blow-molding, such as films and pipes.

Abstract: The invention comprises a catalyst support containing an &agr;-olefin polymer which is in the form of particles of mean size from 5 to 350 &mgr;m in which the pore volume generated by the pores of radius from 1,000 to 75,000 Å is at least 0.2 cm3/g. A catalyst usable for the polymerization of &agr;-olefins, including a compound containing at least one transition metal belonging to groups IIIb, IVb, IVb and VIb of the Periodic Table, bound in or on this support, is also described.

Abstract: Process for the polymerization of olefins using a catalytic system comprising a solid precursor containing at least one neutral halogenated metallocene derived from a transition metal and at least one ionizing agent, and an organometallic compound derived from a metal chosen from groups IA, IIA, IIB, IIIA, and IVA of the Periodic Table.

Abstract: A catalyst system which combines a unbridged metallocene catalyst and a heterogeneous catalyst affects the molecular weight, the molecular weight distribution and the melt flow index of the resulting polymer. To obtain a polymer having high molecular weight and fractional melt flow index, the unbridged metallocene compound is preferably cyclopentadienyltitanium trichloride or bis(cyclopentadienyl)titanium dichloride and an alumoxane co-catalyst may or may not be present. To obtain a polymer having high molecular weight, broad molecular weight distribution and fractional melt flow index, the unbridged metallocene compound is preferably cyclopentadienyltitanium trichloride or bis(cyclopentadienyl)titanium dichloride and an alumoxane co-catalyst is present. A catalyst system which combines a unbridged metallocene catalyst and a bridged metallocene catalyst with the heterogeneous catalyst affects the xylene solubles in addition to the other polymer properties.

Abstract: Ethylene polymer having a die swell ratio (RB) of at least 1.4, a resistance to crazing under stress (ESCR) of at least 55 h and a melt index (MI5) of at least 0.2 g/10 min. Processes for obtaining this ethylene polymer using different catalytic systems, the first based on titanium and zirconium used in a polymerization in two reactors; the second consisting of a mixture of a titanium catalyst and a titanium and zirconium catalyst, used in a polymerization in two reactors; the third based on chromium on a support comprising at least two constituents chosen from silica, alumina and aluminum phosphates, used in a polymerization in a single or in two reactors.

Abstract: Multiphase homo- or copolymers of C2-C10-alk-1-enes are prepared by a process in which polymerization is effected in the presence of two different catalyst systems in one reaction zone, one of the catalyst systems containing, as active components, a metallocene complex of the general formula (I) or (II) where M1 is a metal of group IVb, Vb or VIb of the Periodic Table, R1 and R2 are identical or different and are each hydrogen, C1-C10-alkyl, C1-C10-alkoxy, C6-C10-aryl, C6-C10-aryloxy, C2-C10-alkenyl, C7-C40-arylalkyl, C7-C40-alkylaryl, C8-C40-arylalkenyl or halogen, R3 and R4 are identical or different and are each hydrogen, halogen, C1-C10-alkyl which may be halogenated, C6-C10-aryl or an —NR210, —SR10, —OSiR310, —SiR310 or —PR210 radical, where R10 is halogen, C1-C10-alkyl or C6-C10-aryl, and R5 and R6 are identical or different and have the meanings stated for R3 and R4, with the proviso that R5 and R6 are not hydrogen.

Abstract: Polymers of ethylene are obtainable by polymerization of ethylene and, if desired, further comonomers in the presence of a catalyst system comprising as active constituents I) a Phillips catalyst, II) a solid which is different from I) and comprises a component which is derived from the metallocene complexes of the formula (A) in which the substituents and indices have the following meanings:  R1 to R10 are hydrogen, C1-C10-alkyl, 5-to 7-membered cycloalkyl which may in turn bear C1-C6-alkyl groups as substituents, C6-C15-aryl or aryalkyl, where two adjacent radicals may also together form a cyclic group having from 4 to 15 carbon atoms, or Si(R11)3, where R11 is C1-C10-alkyl, C6-C15-aryl or C3-C10-cycloalkyl, or the radicals R4 and R9 together form a group —[Y(R12R13)]m—, where Y is silicon, germanium, tin or carbon, and R12, R13 are hydrogen C1-C10-alky, C3-C10-cycloalyl or C6-C15-aryl, M is a metal of transition groups IV to VIII or a metal of the lanthanide

Abstract: A method for producing a low density copolymer of ethylene and 1-hexene having a density in the range of about 0.915 to about 0.930 grams/cc in a continuous loop reactor under slurry phase reactor conditions in the presence of a liquid diluent comprising (a) using a prepolymerized solid particulate metallocene catalyst system, (b) combining the catalyst system with a liquid diluent, and (c) agitating the mixture of (b) to form a liquid mixture containing catalyst system particles that are substantially uniform in size, (d) passing this liquid mixture into the loop reactor, (e) not adding any hydrogen, (f) employing the temperature in the range of about 170.degree. F. to about 180.degree. F., (g) employing ethylene in an amount equal to about 5 to about 6 weight % of the liquid diluent and the loop reactor, and (h) employing 1-hexene in an amount equal to about 1.5 to about 2.5 weight % of the liquid diluent in the loop reactor.

Abstract: Yttrium complexes of dibenzopyrolyl substituted cyclopentadienyl ligands are useful as ethylene polymerization catalysts to uniquely prepare low molecular weight ethylene polymers having a high degree of terminal vinyl unsaturation.

Abstract: Provided are heterogeneous catalysts for homo- and copolymerization of olefins as well as a method for preparing these catalysts, which comprise at least one metallocene compound of a Group 4A, 5A or 6A (Hubbard) transition metal on a solid inorganic support. The method comprises the steps of vaporizing the metallocene compound, treating the support material with the vaporized metallocene compound at a temperature which is sufficiently high to keep the metallocene compound in the vaporous state, contacting the support material with an amount of the vaporized metallocene compound which is sufficient to allow for a reaction between the metallocene compound and at least a substantial part of the available surface sites capable of reacting therewith, removing the rest of the metallocene compound not bound to the support, and optionally treating the product thus obtained with an activating agent. The catalysts are active even if very low amounts of activator agents, such as alumoxane, are used.

Abstract: The invention provides catalysts which have a high polymerization activity, enable the obtaining of olefin polymers of wide molecular weight distribution, and which comprise (a)(a-1) a metallocene compound or (a-2) a titanium catalyst component containing magnesium, titanium, and halogen, (b) a compound of a transition metal from Groups 8 to 10 of the periodic table and is of the general formula shown below, and a cocatalyst component. ##STR1## The invention also provides olefin polymer compositions excellent in rigidity and impact resistance which can be produced using a catalyst comprising the transition metal compound (b) and which comprises a non-crystalline olefin polymer having a specific intrinsic viscosity, glass transition temperature and density, and another known olefin polymer.

Abstract: A mixed catalyst composition comprising a) a solid Ziegler-Natta catalyst; b) a liquid single site catalyst; and c) at least one activating cocatalyst is provided. Polymers having a broad or bimodal molecular weight distribution may be made with this catalyst composition.

Abstract: A process for polymerizing an alpha-olefin using either a catalyst formed by contacting a highly active solid titanium catalyst component, an organo-metallic compound of a metal of Group 1 to 3 of the periodic table, an organic halogen compound or a transition metal compound, and an organosilicon compound or a sterically hindered amine in an inert medium in the absence of an alpha olefin, or a catalyst prepared by preliminarily polymerizing an alpha olefin in the presence of a catalyst comprising the above four catalyst components, provided that the last one is an optional component. This process achieves the industrially advantage that the catalysts are highly active, and give a polymer having excellent stereoregularity.

Abstract: Polyethylenes are disclosed herein which are derived from an ethylene monomer and in which any quaternary carbon atom is not present in a polymeric main chain; and the activation energy (Ea) of melt flow is in the range of 8 to 20 kcal/mol; as well as(1) a Huggins coefficient (k) and an intrinsic viscosity [.eta.] meet the relation of the equationk.gtoreq.0.2+0.0743.times.[.eta.];(2) a molar ratio [CH.sub.3 /CH.sub.2 ] of a methyl group to a methylene group is in a region of 0.005 to 0.1 and meets the equationTm.gtoreq.131-1340[CH.sub.3 /CH.sub.2 ];(3) an Mw and a die swell ratio (DR) meet the equationDR>0.5+0.125.times.log Mw; or(4) in the measurement of a loss elastic modulus, a .beta.-relaxation peak is present in the range of 0 to -100.degree. C.These polyethylenes are different from a usual HDPE, L-LDPE and LDPE, and they are excellent in working properties and permit the control of physical properties such as density, a melting point and crystallinity mainly in the state of a homopolymer.

Abstract: Components and catalysts for the polymerization of olefins comprising the product obtained by contacting a compound of a transition metal M, containing at least one M-.pi. bond, with an olefinic prepolymer obtained by polymerization of one or more olefins with a coordination catalyst comprising a compound of Ti or V supported on a magnesium halide.

Abstract: Blends of olefin polymers and syndiotactic vinyl polymers are produced by the catalytic polymerization of olefins and aromatic vinyl compounds or methacrylate esters as vinyl compounds in inert diluents in the presence of a catalyst mixture of transition metal compounds, metalloxane compounds and metal alkyl compounds.The blends have a finely dispersed distribution of the blending components and are suitable for the production of films, sheets, fibers, panels, coatings, pipes, hollow objects, injection molded products and foams.

Abstract: A process is provided for preparing polymer compositions which are multimodal in nature. The process involves contacting, under polymerization conditions, a selected addition polymerizable monomer with a metallocene catalyst having two or more distinct and chemically different active sites, and a catalyst activator.

Abstract: It has been found that the use of at least one unsupported metallocene polymerization catalyst with at least one supported metallocene polymerization catalyst in the polymerization of olefins allows for better control of the polymerization, especially gas phase polymerization. Such a system takes advantage of the high activity of the unsupported catalyst and the stability of a supported catalyst. Additionally, the relative timing of the addition of the supported and unsupported catalysts to a reaction system can be used to control a continuous polymerization reaction by stabilizing the reactor bed with the supported catalyst prior to addition of the unsupported catalyst.

Abstract: Disclosed is a polymetallic supported catalyst component comprising an activated anhydrous MgCl.sub.2 solid support which has been treated with at least one treatment of at least two halogen-containing transition metal compounds, wherein one is a halogen-containing titanium metal compound and one is a halogen-containing non-titanium transition metal compound, optionally, in the presence of an electron donor and the processes for producing the component. A catalyst for the polymerization of at least one alpha-olefin of the formula CH.sub.2 =CHR, where R is H or a C.sub.1-12 branched or straight chain alkyl or substituted or unsubstituted cycloalkyl, by reacting this supported catalyst component with an organometallic cocatalyst, optionally in the presence of an electron donor, and the polymerization of at least one alpha-olefin with the catalyst are also disclosed.

Abstract: A catalyst composition is described for preparing a high activity catalyst in silica which produces, in a single reactor, polyethylene with a broad or bimodal molecular weight distribution. The catalyst is prepared from the interaction of silica, previously calcined at 600.degree. C., with dibutylmagnesium, 1-butanol and titanium tetrachloride and a solution of methylalumoxane and ethylenebis[1-indenyl]zirconium dichloride.

Abstract: The invention relates to a catalyst component which is a tract product of reagents comprising silica which has a pore volume which exceeds 2.9 cc/gram and an average pore diameter which exceed 400 Angstroms;a metallocene of a first transition metal, activated by an alumoxane,a contact product of dialkylmagnesium and trialkylsilanol,a second transition metal source which exhibits a hydrogen response which is different from that of the metallocenean olefin of 4 to 20 carbon atoms. This catalyst component is activated by an aluminum alkyl activator.

Abstract: Disclosed are a catalyst for olefin polymerization comprising (A) a compound of a transition metal in Group IVB of the periodic table which contains a ligand having a cyclopentadienyl skeleton, (B) an organoaluminum compound and any one of (C1) a Br.phi.nsted acid; (C2) a material obtained by contacting (c-1) a magnesium compound with (c-2) an electron donor; and (C3) a material obtained by contacting (c-1) a magnesium compound, (c-2) an electron donor and (c-3) an organometallic compound with each other. Also disclosed are processes for polymerizing an olefin in the presence of the above-mentioned catalysts for olefin polymerization. Such catalysts and processes for olefin polymerization as described above are excellent in olefin polymerization activity and economical efficiency.

Abstract: A catalytic solid for (co)polymerization of ethylene, includes (a) at least one inorganic support; (b) at least one transition metal metallocene having a formula (C.sub.p).sub.a (C.sub.p ').sub.h MX.sub.x Z.sub.z, in which C.sub.p and C.sub.p each denote a cyclopentadienyl, indenyl, or fluorenyl radical or a substituted derivative of such a radical, coordinated to the central atom M, optionally the groups C.sub.p and C.sub.p are linked via a covalent bridge, M denotes the at lease one transition metal, which is selected from the group consisting of scandium, titanium, zirconium, hafnium and vanadium, a, b, x and z denote integers such that (a+b+x+z)=m, x>0, z.gtoreq.0 and a and/or b.noteq.0, m denotes the valency of the at least one transition metal M, X denotes a halogen, and Z denotes a hydrocarbon radical which may optionally comprise oxygen or a silyl radical of formula (--R.sub.

Abstract: There is provided a process for preparing a polydiene comprising polymerizing a diene selected from the group consisting of butadiene, isoprene, or a mixture thereof under polymerization conditions in a gas phase reactor optionally in the presence of an inert particulate material and in the presence of a catalyst comprising (i) a rare earth metal component, (ii) a transition metal component selected from the group consisting of nickel compound, cobalt compound or titanium compound, and (iii) cocatalyst.

Abstract: A process is provided for preparing polymer compositions which are multimodal in nature. The process involves contacting, under polymerization conditions, a selected addition polymerizable monomer with a metallocene catalyst having two or more distinct and chemically different active sites, and a catalyst activator.

Abstract: Disclosed is a process for preparing a solid titanium catalyst component, comprising contacting (a) a liquid magnesium compound, (b) a liquid titanium compound, (c) an electron donor and (d) a solid divalent metallic halide. In this process, the solid divalent metallic halide is one having a crystalline structure of the cadmium chloride type. The contact of the component (a) with the component (b) is preferably carried out in the presence of the solid divalent metallic halide (d). According to this process, there can be obtained a solid titanium catalyst component capable of polymerizing olefins with an extremely high activity and capable of producing polyolefins of high stereoregularity when .alpha.-olefins of 3 or more carbon atoms are polymerized.

Abstract: A supported catalyst for the (co)polymerization of alpha-olefins is obtained by putting the following products in contact with each other:(A) a metallocene derivative of a metal selected from the group consisting of transition metals and lanthanides, which is in itself capable of promoting the polymerization of alpha-olefins in the presence of or also without suitable activators;(B) an active support containing magnesium, halogen, titanium and smaller quantities of tin;(C) an organometal derivative of aluminium of which at least 50% of the aluminium atoms are bound to at least one alkyl carbon atom.Components (A) and (B) are preferably interacted first to obtain a supported metallocene derivative, which is then put in contact with (C) to obtain the desired catalyst. Alternatively, (B) and (C) are interacted and subsequently put in contact with (A).

Abstract: A process for the production of polyolefins is provided which comprises polymerizing or copolymerizing olefins in the presence of a catalyst composition which includes a catalyst component (I) resulting from mutual contact of sub-components (A) and (B), and a catalyst component (II). Sub-component (A) is of the formulaR.sup.1.sub.p Me.sup.1 X.sup.1.sub.4-p and/or R.sup.1.sub.2 Me.sup.1 X.sup.1'and sub-component (B) is a modified organoaluminum compound having Al--O--Al bonds. Catalyst component (II) is an admixture of sub-component (C), which is a transition metal elemental compound of Groups VII-VIII, and one or more of triethylaluminum, triisobutylaluminum, diethyl zinc, n-butyllithium, and butylmagnesiumchloride. The catalyst components (I) and/or (II) are contacted with a carrier during or after the preparation of the components (I) and/or (II).

Abstract: There is disclosed a process for producing a styrenic polymer which comprises polymerizing at least one styrenic monomer by the use of a polymerization catalyst comprising in combination (A) at least one transition metal compounds, (B) an aluminoxane, (C) a coordination complex compound comprising a cation and an anion in which a plurality of radicals are bonded to a metal and (D) an organoaluminum compound. The above process is capable of producing a styrenic polymer which has high degree of syndiotactic configuration and a wide range of molecular weight distribution and is minimized in residual metallic components at a low production cast with a high efficiency.

Abstract: The present invention provides an ethylene copolymer comprising constituent units (a) derived from ethylene and constituent units (b) derived from an .alpha.-olefin having 3 to 20 carbon atoms, the ethylene copolymer being characterized in that(A) the ethylene copolymer has a density (d) of 0.86 to 0.95 g/cm.sup.3 ;(B) the ethylene copolymer has a MFR of 0.001 to 50 g/10 min as measured at a temperature of 190.degree. C. and a load of 2.16 kg;(C) the melt tension (MT) and MFR of the ethylene copolymer satisfy the relationlog MT>-0.66 log MFR+0.6; and(D) the temperature (T) at which the exothermic curve of the ethylene copolymer measured by a differential scanning calorimeter (DSC) shows the highest peak and the density (d) satisfy the relationT<400 d-250.

Abstract: A catalyst system for olefin polymerization, including a catalytic solid based on chromium deposited on a support containing silica, alumina and aluminium phosphate and a cocatalyst chosen from organoaluminium compounds. One of the essential characteristics of the invention is the combination of an organoaluminium compound as cocatalyst with a catalytic solid based on chromium deposited on a support containing silica, alumina and aluminium phosphate.

Abstract: Disclosed in an olefin polymerization catalyst comprising a transition metal compound having at least two transition metals in which at least one of said metals is bonded to a ligand having a cyclopentadienyl skeleton, at least one of said metals is selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals and at least on of the others is selected from the specific transition metals; and an organoaluminum oxy-compound or an organoboron compound. Corresponding to the kind of the metal combined with said metal selected from Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W and lanthanoid metals, the olefin polymerization catalyst exhibit a property to give polymers having a wide molecular weight distribution in spite of the catalyst system using one kind of a transition metal compound, or to give polymers having high molecular weight and be excellent in the polymerization activity at low polymerization temperature.

Abstract: The present invention relates to a prepolymer for the polymerization of olefins, the said prepolymer achieving a combination of a number of solid catalytic components for the polymerization of olefins. The combination of catalytic components makes it possible to combine two properties within the same polymer, one of the properties being contributed by one of the catalytic components and the other property being contributed by the other catalytic component.

Abstract: The present invention provides a catalyst and a process for increased catalyst activity and polymer yield. The catalyst system used in the process includes at least two supported metallocene catalyst precursor in combination with an oxyorganoaluminum. The process can be applied to the polymerization of olefins, preferably olefin of three carbon atoms and higher, particularly propylene. The catalyst activity and polymer yield for a dual supported metallocene catalyst are increased over that for a single supported metallocene catalyst. The polymer produced by this dual supported metallocene system has a relatively broad molecular weight distribution.

Abstract: The present invention provides processes for preparing olefin polymers, by which olefin polymers composed of a propylene block copolymer component and an ethylene/.alpha.-olefin copolymer component are directly prepared by polymerization and olefin polymers excellent in impact resistance as well as in mechanical strength such as rigidity, moldability and heat resistance can be prepared. In the processes of the invention, a step (i) for preparing a crystalline polypropylene component and a step (ii) for preparing a low-crystalline or non-crystalline ethylene/.alpha.-olefin copolymer component are carried out in an arbitrary order using an olefin polymerization catalyst to form a propylene block copolymer component; then another catalyst component is added to the polymerization system; and a step (iii) for preparing a low-crystalline or non-crystalline ethylene/.alpha.-olefin copolymer component is carried out.

Abstract: A process for preparing polynuclear metallocenes by reacting a metallocene in which one of the cyclopentadienyl-containing radicals has a substituent having olefinic or acetylenic unsaturation with a second metallocene having a metal which comes from groups IVb to VIb of the periodic table and a metal-hydride bond. The use of the resulting metallocenes in the polymerization of olefins is disclosed, including techniques for using such metallocenes to produce solid prepolymerized metallocene-containing catalyst systems suitable for use in the polymerization of olefins.

Abstract: The present invention is a catalyst system to produce polymer blends in a single reactor, polymer blends of isotactic polyolefins and syndiotactic polyolefins. The catalyst system is a combination of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The multi-catalyst system is obtained by mixing the components of at least one metallocene catalyst and at least one conventional supported Ziegler-Natta catalyst. The metallocene catalyst comprises solid complx of a metallocene compound and an ionizing agent. The conventional supported Ziegler-Natta catalyst comprises an aluminum alkyl and a transition metal compound with, optionally, an electron donor.

Abstract: Novel chromium-containing compounds are prepared by forming a mixture of a chromium salt, a metal amide, and an ether. These novel chromium-containing, or chromium pyrrolide, compounds, with a metal alkyl and an unsaturated hydrocarbon, can be used as a cocatalyst system in the presence of an olefin polymerization catalyst system to produce a comonomer in-situ. The resultant polymer, although produced from predominately one monomer, has characteristics of a copolymer.

Abstract: There are disclosed a transition metal compound of the general formula RMX.sub.a-1 L.sub.b (R is a .pi. ligand, a fused polycyclic cyclopentadienyl group in which at least one of many-membered rings to which cyclopentadienyl groups are fusedly bonded is a saturated ring, M is a transition metal, X is a .sigma. ligand, L is a Lewis base, a is the valency of M, and b is 0, 1 or 2); a polymerization catalyst for styrene, etc. comprising the above transition metal, preferably further comprising an oxygen atom containing compound ionic compound or organoboron compound and optionally a Lewis base; and a process for producing a polymer of a compound containing an ethylenically unsaturated double bond or an acetylenic polymer, especially a syndiotactic polystyrene by using the above polymerization catalyst. The catalyst is particularly effective for producing highly syndiotactic polystyrene minimized in residual metals amounts at a low cost in enhanced efficiency.