Abstract: A syndiotactic polyolefin is obtained in a high yield by polymerization or copolymerization of an olefin of the formula R.sup.a --CH.dbd.CH--R.sup.b in the presence of a catalyst consisting of a metallocene of the formula I ##STR1## in which M.sup.1 is titanium, zirconium, vanadium, niobium or tantalum, and an aluminoxane. This polyolefin has a very high molecular weight, a very narrow molecular weight distribution and a very high syndiotactic index. Shaped articles produced from the polymer are distinguished by a high transparency, flexibility, tear resistance and an excellent surface gloss.

Abstract: Process for the preparation of a polypropylene molding compositionA 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: Propylene isoblock polymers with 0.5 to 10 mol %, based on the total polymer, of randomly distributed ethylene content and with a narrow molecular weight distribution and rubber-like properties are obtained when propylene is polymerized using a catalyst comprising an aluminoxane and a chiral metallocene, containing bridges, of formula I: ##STR1## in which M.sup.1 is preferably hafnium or zirconium,R.sup.1 and R.sup.2 are preferably halogen (e.g. C1) atoms,R.sub.3 through R.sup.6 are hydrogen or C.sub.1 -C.sub.10 alkyl, and pair of adjacent radicals R.sup.3, R.sup.4, R.sup.5, and R.sup.6 can form an aromatic ring with the C-atoms to which they are bonded, andR.sup.7 is preferably --Si(CH.sub.3).sub.2 --Si(CH.sub.3).sub.2 --.

Abstract: A process for the preparation of an olefin polymer by polymerization or copolymerization of an olefin of the formula R.sup.a --CH.dbd.CH--R.sup.b, in which R.sup.a and R.sup.b are identical or different and are a hydrogen atom or a hydrocarbon radical having 1 to 14 carbon atoms, or R.sup.a and R.sup.b, together with the atoms connecting them, can form a ring, at a temperature of from -60.degree. to 200.degree. C., at a pressure of from 0.5 to 100 bar, in solution, in suspension or in the gas phase, in the presence of a catalyst formed from a metallocene in the meso-form or a meso:rac mixture, with meso:rac>1:99, as transition-metal compound and a cocatalyst, wherein the metallocene is a compound of the formula I, ##STR1## in which M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are identical or different and are methyl or chlorine, R.sup.3 and R.sup.6 are identical or different and are methyl, isopropyl, phenyl, ethyl or trifluoromethyl, R.sup.4 and R.sup.5 are hydrogen or as defined for R.sup.3 and R.sup.

Abstract: A very efficient catalyst system for the polymerization of 1-olefins consists of an aluminoxane and a metallocene which is a compound of the formula I ##STR1## in which R.sup.1 and R.sup.2 denote hydrogen atoms, halogen atoms or hydrocarbon radicals and R.sup.3 and R.sup.4 are mononuclear or polynuclear hydrocarbon radicals which can form a sandwich structure with the central atom and which are linked to one another by a --R.sup.6.sub.m --R.sup.5 --R.sup.7.sub.n -- bridge containing a hetero atom and consisting of one or several members.The catalyst system produces polymers having a high molecular weight.

Abstract: A process for the preparation of an olefin polymer by polymerization or copolymerization of an olefin of the formula R.sup.a --CH.dbd.CH--R.sup.b, in which R.sup.a and R.sup.b are identical or different and are a hydrogen atom or a hydrocarbon radical having 1 to 14 carbon atoms, or R.sup.a and R.sup.b, together with the atoms connecting them, can form a ring, at a temperature of from -60.degree. to 200.degree. C., at a pressure of from 0.5 to 100 bar, in solution, in suspension or in the gas phase, in the presence of a catalyst formed from a metallocene in the meso-form or a meso:rac mixture, with meso:rac>1:99, as transition-metal compound and a cocatalyst, wherein the metallocene is a compound of the formula I, ##STR1## in which M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are identical or different and are methyl or chlorine, R.sup.3 and R.sup.6 are identical or different and are methyl, isopropyl, phenyl, ethyl or trifluoromethyl, R.sup.4 and R.sup.5 are hydrogen or as defined for R.sup.3 and R.sup.

Abstract: A syndiotactic propylene copolymer is obtained in high yields by copolymerization of propylene with small amounts of other olefins in the presence of a catalyst comprising a metallocene of the formula I ##STR1## in which M.sup.1 is titanium, zirconium, hafnium, vanadium, niobium or tantalum and an aluminoxane. This copolymer has a very high molecular weight, a very narrow molecular weight distribution, very high syndiotaxicity, advantageously low melting points and rubber-like behavior. Molded articles produced from the polymer are distinguished by high transparency, flexibility and tear strength. Their main areas of application are packagings of any type.

Abstract: A syndiotactic propylene copolymer is obtained in high yields by copolymerization of propylene with small amounts of other olefins in the presence of a catalyst comprising a metallocene of the formula I ##STR1## in which M.sup.1 is titanium, zirconium, hafnium, vanadium, niobium or tantalum and an aluminoxane. This copolymer has a very high molecular weight, a very narrow molecular weight distribution, very high syndiotaxicity, advantageously low melting points and rubber-like behavior. Molded articles produced from the polymer are distinguished by high transparency, flexibility and tear strength. Their main areas of application are packagings of any type.

Abstract: A highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I ##STR1## where M.sup.1 =Zr or Hf, R.sup.1 and R.sup.2 =(C.sub.1 -C.sub.4)-alkyl or chlorine, R.sup.3, with the proviso that at least one of the radicals R.sup.3 is not hydrogen, =hydrogen, F, Cl, --OR.sup.7, --NR.sup.7 R.sup.8, --P(O)R.sup.7 R.sup.8, --P(OR.sup.7).sub.2 or SR.sup.7, R.sup.4 is a ##STR2## radical, and m plus n are zero or 1.

Abstract: Bulk polymerization using specific metallocene catalysts for the preparation of cycloolefin polymersPolymers of polycyclic olefins, such as, for example, norbornene or tetracyclododecene, or copolymers of polycyclic olefins with cycloolefins and/or 1-olefins are obtained without ring opening, in high space-time yield, with a high cycloolefin incorporation rate and at industrially favorable polymerization temperatures, by bulk polymerization in which a catalyst is used which comprises an aluminoxane and a stereorigid chiral metallocene compound of an element from groups IVb to VIb, where the hydrocarbon radicals forming the sandwich structure are different.

Abstract: A very effective catalyst system for olefin polymerization consists of a cocatalyst, preferably an aluminoxane, and a metallocene of the formula (I) ##STR1## in which, preferably, M.sup.1 is Zr, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 to R.sup.6 are alkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a chain having one or more members, in which R.sup.7 can also be a (substituted) hetero atom, and m+n is zero or 1. The catalyst system leads to polymers of variable molecular weight and stereotacticity, depending on the substituents R.sup.3 to R.sup.6 chosen, at polymerization temperatures which are relevant in industry.

Abstract: Chemically homogeneous cycloolefin copolymers of polycyclic olefins, such as, for example, norbornene or tetracyclododecene, with cycloolefins and/or acyclic olefins are obtained without ring opening and in a high space-time yield if a catalyst system is used which comprises an aluminoxane and a stereorigid metallocene compound of an element from groups IVb to VIb, of the formula ##STR1## the part of the metallocene molecule formed by M.sup.1 and the substituents R.sup.16 -R.sup.17 having C.sub.1 -symmetry or being in the meso-form.

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 very active catalyst system for olefin polymerization comprises a cocatalyst, preferably an aluminoxane, and a metallocene of the formula I or Ia ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen or alkyl, R.sup.5 and R.sup.6 are alkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n is a chain with one or more members, in which R.sup.7 can also be a (substituted) heteroatom, and m+n is zero or 1.

Abstract: A very effective catalyst system for olefin polymerization consists of a cocatalyst, preferably an aluminoxane, and a metallocene of the formula (I) ##STR1## in which, preferably, M.sup.1 is Zr, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 to R.sup.6 are alkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a chain having one or more members, in which R.sup.7 can also be a (substituted) hetero atom, and m+n is zero or 1. The catalyst system leads to polymers of variable molecular weight and stereotacticity, depending on the substituents R.sup.3 to R.sup.6 chosen, at polymerization temperatures which are relevant in industry.

Abstract: The novel metallocenes of the formula I ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen, R.sup.5 and R.sup.6 are alkyl or haloalkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a single- or multi-membered chain in which R.sup.7 may also be a (substituted) hetero atom, m+n is zero or 1, and R.sup.10 is hydrogen, form, together with aluminoxanes as cocatalysts, a very effective catalyst system for the preparation of polyolefins of high stereospecificity and high melting point.

Abstract: An immobile (heterogeneous) metallocene catalyst component which can advantageously be used for olefin polymerization is obtained by homopolymerization of appropriately substituted (vinyl group-containing) metallocenes of group IVb of the periodic table or by copolymerization of such metallocenes with (di)vinylaromatic compounds.

Abstract: A very active catalyst system for olefin polymerization is composed of an aluminoxane and a metallocene of the formula I ##STR1## wherein preferably M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen, R.sup.5 and R.sup.6 are alkyl or haloalkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.m --is a single-membered or multimembered chain in which R.sup.7 may also be a (substituted) hetero atom, and m+n is zero or 1. The catalyst system gives polymers having a high molecular weight and high stereospecificity.

Abstract: A very active catalyst system for olefin polymerization is composed of an aluminoxane and a metallocene of the formula I ##STR1## in which, preferably, M.sup.1 is Zr or Hf, R.sup.1 and R.sup.2 are alkyl or halogen, R.sup.3 and R.sup.4 are hydrogen, R.sup.5 and R.sup.6 are alkyl or haloalkyl, --(CR.sup.8 R.sup.9).sub.m --R.sup.7 --(CR.sup.8 R.sup.9).sub.n -- is a single-membered or multimembered chain in which R.sup.7 may furthermore be a (substituted) hetero atom, m+n is zero or 1 and R.sup.10 is hydrogen. The catalyst system gives polymers having high stereospecificity and a high melting point.

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.