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: Syndiotactic polyolefins having a molecular weight distribution M.sub.w /M.sub.n of >3 and which may be monomodal, bimodal or multimodal are obtained by polymerization or copolymerization of olefins of the formula RCH.dbd.CHR, in which a catalyst system comprising an aluminoxane and a transition-metal component (metallocene) is used, the transition-metal component comprising at least 2 metallocenes of the formula ##STR1## which are stereorigid and whose moiety formed by Zr and the substituents R.sup.1 -R.sup.4 has C.sub.s symmetry or slightly distorted C.sub.s symmetry.

Abstract: Syndiotactic polyolefins having a molecular weight distribution M.sub.w /M.sub.n of .gtoreq.3 and which may be monomodal, bimodal or multimodal are obtained by polymerization or copolymerization of olefins of the formula RCH.dbd.CHR, in which a catalyst system comprising an aluminoxane and a transition-metal component (metallocene) is used, the transition-metal component comprising at least 2 metallocenes of the formula ##STR1## which are stereorigid and whose moiety formed by Zr and the substituents R.sup.1 -R.sup.4 has C.sub.s symmetry or slightly distorted C.sub.s symmetry.

Abstract: Metallocenes having benzo-fused indenyl derivatives as ligands, processes for their preparation and their use as catalysts A very effective catalyst system for olefin polymerization comprises a cocatalyst, preferably 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 halogen or alkyl, R.sup.3 is alkyl, R.sup.4 to R.sup.10 are alkyl or hydrogen and R.sup.11 is a (substituted) alkylene or heteroatom bridge.

Abstract: Process for the preparation of an olefin polymer using metallocenes containing specifically substituted indenyl ligandsA highly effective catalyst system for the polymerization of olefins comprises a cocatalyst, preferably 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.5 is hydrogen or alkyl, R.sup.3 and R.sup.4 are alkyl, where R.sup.3, R.sup.4 and R.sup.5 may be halogenated, --(CR.sup.7 R.sup.8).sub.m --R.sup.6 --(CR.sup.7 R.sup.8).sub.n -- is a single- or multi-membered chain in which R.sup.6 may also be a (substituted) heteroatom, and m+n is zero or 1.

Abstract: A very active catalyst system for olefin polymerization comprises a cocatalyst, preferably 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 is hydrogen, R.sup.4 to R.sup.6 and alkyl or aryl, --(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' can also be a (substituted) hetero atom, and m+n is zero or 1.

Abstract: Polyolefins having a molecular weight distribution M.sub.w /M.sub.n of .gtoreq.3 and which may be monomodal, bimodal or multimodal are obtained by polymerization or copolymerization of olefins of the formula RCH.dbd.CHR, in which a catalyst system comprising an aluminoxane and a transition-metal component (metallocene) is used, the transition-metal component comprising at least one zirconocene of the formula I ##STR1## and at least one zirconocene of the formula Ia or alternatively at least 2 zirconocenes of the formula I.

Abstract: A very active catalyst system for olefin polymerization comprises a cocatalyst, preferably 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 is hydrogen, R.sup.4 to R.sup.6 are alkyl or aryl, --(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 can also be a (substituted) hetero atom, and m+n is zero or 1.

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: 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: A polyolefin film which comprises a polypropylene base layer and at least one top layer of a propylene polymer, wherein the base layer is formed of an isotactic polypropylene and the top layer of a syndiotactic polypropylene, has high sealed-seam strength and excellent optical properties and is useful as, for example, a packaging material.

Abstract: A polyolefin film which comprises a polypropylene base layer and at least one top layer comprising a propylene polymer, wherein the base layer is formed of an isotactic polypropylene and the top layer of a copolymer of an o-olefin having 2 to 8 carbon atoms and a syndiotactic propylene, has high sealed-seam strength and excellent optical properties and is useful as, for example, a packaging material.

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.

Abstract: Olefins of the formulaR.sup.11 --CH.dbd.CH--R.sup.12(R.sup.11 and R.sup.12 =H or C.sub.1 -C.sub.14 -alkyl) are polymerized in the presence of a catalyst comprising at least one metallocene of the formula I ##STR1## (M=zirconium or hafnium) and an aluminoxane, giving polymers of high molecular weight in high yield.