Abstract: Propylene-ethylene copolymers obtainable by three-step polymerization from the gas phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system which, in addition to a titanium-containing solid component, also contains, as cocatalyst, an aluminum compound, where, in a first polymerization step, propylene is polymerized at from 60 to 90° C. and at from 20 to 40 bar and at a mean residence time of the reaction mixture of from 0.5 to 5 hours, then, in a second polymerization step, a mixture of propylene and ethylene is polymerized onto the polymer obtained from the first polymerization step at from 40 to 110° C. and from 5 to 30 bar, this pressure being at least 7 bar below the pressure in the first polymerization step, and at a mean residence time of the reaction mixture of from 0.2 to 4 hours, and then, in a third polymerization step, ethylene or a mixture of ethylene and propylene is polymerized onto the polymer obtained from the second polymerization step at from 40 to 110° C.

Abstract: High-flow propylene/ethylene copolymers which have a melt flow index of from 2 to 200 g/min under a load of 2.16 kg at 230.degree. C. and which may be produced from the gas phase by polymerization in two stages in an agitated fixed bed in the presence of hydrogen acting as chain stoppage regulator and using a Ziegler-Natta catalyst system comprising a titaniferous solid component which contains a magnesium compound on finely divided silicon oxide or on finely divided aluminum oxide or on a finely divided aluminum silicate having the empirical formula SiO.sub.2.aAl.sub.2 O.sub.3, where a stands for a value between 0.001 and 2, and an aluminum component, by means of a procedure comprisinga) a first polymerization stage in which propylene is polymerized under a pressure of from 20 to 40 bar and at a temperature of from 60.degree. to 90.degree. C.

Abstract: Copolymers of propylene with other 1-alkenes, obtainable by gas-phase polymerization of a mixture of propylene and another 1-alkene in the absence of a liquid reaction medium under a pressure of from 15 to 30 bar, at from 60.degree. to 90.degree. C. and with an average holdup time of the polymer of from 1 to 5 hours, with the aid of a Ziegler-Natta catalyst system which, besides a titanium-containing solid component, contains an aluminum component and an electron donor, with the temperature being chosen so that, under the preset pressure, no condensation of the monomer mixture takes place in the gas space and, moreover, the ratio of the partial pressures of propylene and the other 1-alkene is adjusted to from 5:1 to 100:1, are particularly suitable for producing sheets and shaped articles.

Abstract: Propylene polymers have a molecular weight ratio Q (M.sub.w /M.sub.n) of from 6 to 30 and are obtainable by Ziegler-Natta polymerization in the presence of hydrogen as molecular weight regulator and are particularly suitable for the production of films and moldings.

Abstract: Propylene polymer blends containinga) a propylene homopolymer having a melt flow index of from 0.001 to 5 g/10 min, as determined at 230.degree. C. under a load of 2.16 kg,b) a propylene/ethylene copolymer having an ethylene content of from 5 to 80% w/w, andc) a propylene homopolymer having a melt flow index of from 1 to 10.sup.4 g/10 min, as determined at 230.degree. C. under a load of 2.16 kg,the ratio of the melt flow index of the propylene homopolymer c) to that of the propylene homopolymer a) being within the range 10:1 to 10.sup.7 :1.The blends of the invention are high-flow materials showing a broad molecular weight distribution, and are thus readily processible.

Abstract: Propylene copolymers grafted with .alpha.,.beta.-ethylenically unsaturated carboxylic acids or derivatives and containing up to 35% by weight of other C.sub.2 - to C.sub.10 -alk-1-enes are obtainable by reacting the monomer to be grafted with a propylene copolymer at from 1 to 500 bar, where, in the absence of a free-radical initiator, from 0.01 to 1.0% by weight, based on the propylene copolymer, of the monomer to be grafted are admixed with the molten propylene copolymer, and the grafting reaction is carried out at from 210.degree. to 350.degree. C.The propylene copolymers according to the invention can be converted into crosslinked or crosslinkable propylene copolymers by admixing organic crosslinking agents.

Abstract: Partially crosslinked olefin polymers are obtainable by reactinga) an ethylene polymer having a density of from 0.90 to 0.98 g/cm.sup.3 orb) a polymer of from 25 to 95% by weight of a propylene homopolymer and from 5 to 75% by weight of a propylene copolymer with polymerized C.sub.2 -C.sub.10 -alk-1-enes, the comonomer content being from 1 to 45% by weight, based on the total polymer,in the absence of free radical initiators, with from 0.001 to 5% by weight, based on the olefin polymer, of a bismaleimido compound of the general formula (I) ##STR1## where R is C.sub.1 -C.sub.20 -alkyl which may be interrupted by one or more oxygen atoms, or is C.sub.5 -C.sub.7 -cycloalkyl or C.sub.6 -C.sub.15 -aryl, each of which in turn may be substituted by one or more C.sub.1 -C.sub.10 -alkyl and/or C.sub.1 -C.sub.6 -alkoxy and/or C.sub.1 -C.sub.4 -dialkylamino groups, or is a radical of the following formula (II)R.sup.1 -Z-R.sup.2 (II)where R.sup.1 and R.sup.2 independently of one another are each C.sub.1 -C.sub.

Abstract: A partially crosslinked polymer composition comprisinga) a polymer comprising from 25 to 95% by weight of polypropylene and from 5 to 75% by weight of a propylene copolymer with copolymerized C.sub.2 -C.sub.10 -alk-1-enes, the comonomer content being from 1 to 45% by weight, based on the total polymer,b) a random ethylene copolymer containing from 5 to 20% by weight of copolymerized C.sub.3 -C.sub.10 -alk-1-enes and having a density at room temperature of from 0.89 to 0.925 g/cm.sup.3, andc) an organosilane compound of the formula (I)A.sub.4-n SiR.sub.n (I)where A are identical or different acrylates or methacrylates or vinyl groups, R are identical or different C.sub.1 -C.sub.8 -alkoxy or C.sub.1 -C.sub.8 -acetoxy groups, and n is 1, 2 or 3,can be obtained by reacting a polymer mixture of the polymer a) and the random ethylene copolymer b) with the organosilane compound c) in the presence of a free-radical initiator and in the presence of a condensation catalyst at from 180.degree. to 280.degree. C.

Abstract: Partially crosslinked plastics materials having a melt flow index of from 0.1 to 100 g/10 min at 230.degree. C. and under a weight of 2.16 kg, containinga) a polymer of from 25 to 97% by weight of a propylene copolymer (I) which contains from 0.1 to 15% by weight of polymerized C.sub.2 -C.sub.10 -alk-1-enes and of from 3 to 75% by weight of a further propylene copolymer (II) which contains from 15 to 80% by weight of polymerized C.sub.2 -C.sub.10 -alk-1-enes andb) an organosilane compound of the following formula (I)A.sub.4-n SiR.sub.n (I)where the radicals A are identical or different and are each an acrylate or methacrylate or vinyl, the radicals R are identical or different and are each C.sub.1 -C.sub.8 -alkoxy or C.sub.1 -C.sub.8 -acetoxy and n is 1, 2 or 3,are obtainable by reacting the polymer a) with the organosilane compound b) in the presence of a free radical initiator and a condensation catalyst at from 180 to 280.degree. C.

Abstract: Partially crosslinked polyolefin blends containa) a polymer of from 25 to 97% by weight of a propylene polymer (I), which contains from 0 to 15% by weight of polymerized C.sub.2 -C.sub.10 -alka-1-enes, and of from 3 to 75% by weight of a further propylene polymer (II) which contains from 15 to 80% by weight of polymerized C.sub.2 -C.sub.10 -alka-1-enes,b) a random ethylene copolymer containing from 5 to 20% by weight of polymerized C.sub.3 -C.sub.10 -alk-1-enes and having a density of from 0.89 to 0.925 g/cm.sup.3 at room temperature,c) a rubber-like material having a Shore A hardness of from 30 to 90 andd) a bismaleimido compound of the following formula (I) ##STR1## where R is C.sub.1 -C.sub.20 -alkyl which may be interrupted by one or more oxygen atoms,C.sub.5 -C.sub.7 -cycloalkyl or C.sub.6 -C.sub.15 -aryl, each of which in turn may be substituted by one or more C.sub.1 -C.sub.10 -alkyl and/or C.sub.1 -C.sub.6 -alkoxy and/or C.sub.1 -C.sub.

Abstract: Polymer blends containa) from 20 to 70% by weight of a propylene copolymer which in turn consists of from 20 to 65% by weight of a propylene homopolymer and 30 to 85% by weight of a random propylene copolymer containing polymerized C.sub.2 -C.sub.10 -alk-1-enes andb) from 30 to 80% by weight of a polyethylene having a density of from 0.94 to 0.98 g/cm.sup.3 and a melt flow index of less than 15 g/10 min at 190.degree. C. under a weight of 2.16 kg.The novel polymer blends possess, inter alia, high rigidity, high impact strength and little tendency to undergo white fracture and are particularly suitable for the production of films and moldings.

Abstract: A shock-absorbing propylene polymer composite molding containsa. a layer with a thickness of from 0.5 to 10 mm which contains a propylene polymer having a melting point of from 130.degree. to 165.degree. C.,b. an intermediate layer with a thickness of from 0.05 to 0.5 mm comprising a hot-melt adhesive based on an olefin copolymer having a melting point of from 90.degree. to 140.degree. C.,c. a foam layer with a thickness of from 3 to 200 mm and a density of from 0.015 to 0.1 g/cm.sup.3 based on a propylene copolymer having a melting point of from 125.degree. to 155.degree. C.,d. an intermediate layer with a thickness of from 0.05 to 0.5 mm comprising a hot-melt adhesive based on an olefin copolymer having a melting point of from 90.degree. to 140.degree. C.,e. a layer with a thickness of from 0.5 to 10 mm which contains a propylene polymer having a melting point of from 130.degree. to 165.degree. C.

Abstract: Ziegler-Natta-type catalyst systems containing, as active constituents,a) a titanium-containing solid component which also contains magnesium, halogen and a carboxylic acid ester, and, as cocatalyst,b) an aluminum compound,wherein the carboxylic acid ester in the solid component is a diester of a carboxylic acid of the formula Ia or Ib ##STR1## where R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are identical or different and are hydrogen, C.sub.1 - to C.sub.15 -alkyl, C.sub.7 - to C.sub.15 -alkylaryl, or 5- to 7-membered cycloalkyl, which may itself carry C.sub.1 - to C.sub.10 -alkyl groups, are particularly suitable for the preparation of polypropylene and copolymers of propylene containing minor amounts of other .alpha.,.beta.-unsaturated olefinic compounds having from 2 to 12 carbon atoms.

Abstract: Propylene-ethylene copolymers are prepared in an agitated bed of solids by first polymerizing propylene from the gas phase in a first polymerization zone at 20-40 bar and 60.degree.-90.degree. C. by addition of a Ziegler-Natta catalyst system, and copolymerizing in a second polymerization zone at 7-35 bar and 40.degree.-70.degree. C. the finely divided polymer from the first polymerization zone with a mixture of olefins a process which comprises copolymerizing in the second polymerization zone with a mixture of propylene, ethylene and a further .alpha.-olefin of from 4 to 10 carbon atoms, setting the ratio of the partial pressures between propylene and ethylene within the range from 100:20 to 100:120 and that of the partial pressures between propylene and the further .alpha.