Abstract: In a process for the polymerization of C2-C8-alk-1-enes by means of a Ziegler-Natta catalyst system, in which polymerization is carried out from the gas phase in at least one reaction zone at from 40 to 120° C. and pressures of from 1 to 100 bar, the pressure and temperature in the reaction zone are set so that an operating point formed by these parameters in a pressure-temperature diagram is located at from 0.2 to 5.0 bar below the dew line of the respective reaction mixture above which condensation of the C2-C8-alk-1-enes occurs.

Abstract: Propylene polymers containing a matrix of a propylene homopolymer and a copolymer of propylene and other alkenes, wherein, during the separation of the propylene polymers according to tacticity and comonomer distribution of the polymer chains, by first dissolving the propylene polymers in boiling xylene, then cooling the solution at a cooling rate of 10° C./h to 25° C. and thereafter, increasing the temperature, separating the propylene polymers into fractions of different solubility, either one or more of the conditions that i) more than 20% by weight of the matrix remain undissolved on further heating to 112° C. or ii) more than 8% by weight of the matrix remain undissolved on further heating to 117° C. or iii) more than 1% by weight of the matrix remain undissolved on further heating to 122° C. are fulfilled by the matrix which remains undissolved on heating the cooled propylene polymer solution to 80° C.

Abstract: Random copolymers of propylene with other 1-alkenes having up to 10 carbon atoms,

Abstract: Catalyst systems of the Ziegler-Natta type comprise as active constituents

Abstract: A process for preparing a supported transition metal catalyst comprising a particulate organic or inorganic support material, a transition metal complex and a compound capable of forming metallocenium ions comprises the following process steps: a) contacting a solution of a compound capable of forming metallocenium ions with a second solvent in which this compound is only sparingly soluble, in the presence of the support material, b) removing at least part of the solvent from the support material and c) contacting a solution of a mixture of a compound capable of forming metallocenium ions and a transition metal complex with a second solvent in which this mixture is only sparingly soluble, in the presence of the support material obtained as described in a) and b).

Abstract: A semicrystalline propylene polymer composition with good suitability for producing biaxially oriented films and prepared by polymerizing propylene, ethylene and/or C4-C18-1-alkenes, where at least 50 mol % of the monomer units present arise from the polymerization of propylene,

Abstract: A process for preparing a compound of the formula I where R1 and R2 are hydrogen or C1-C4-alkyl and R3 is C1-C10-alkyl, phenyl or C1-C4-alkyl-substituted phenyl, comprises reacting a compound II with a compound of the formula III where X is chlorine, bromine or iodine, in the presence of a Friedel-Crafts catalyst in one step to give a compound I.

Abstract: Flame-retardant thermoplastic molding materials containing A) at least one polyphenylene ether, B) at least one vinylaromatic polymer, and C) at least one flameproofing agent furthermore comprise D) as an antidrip agent, a high molecular weight polymer based on acrylamide having a viscosity of more than about 1.5 mpas, measured in 0.1% strength aqueous solution at 25° C., and are used for the production of fibers, films and moldings.

Abstract: The catalyst systems comprise as active constituents a) a titanium-containing solid component comprising a compound of titanium, a compound of magnesium, a halogen, an inorganic oxide as support and a carboxylic ester as electron donor compound, and also, as cocatalyst, b) an aluminum compound and c) optionally a further electron donor compound, wherein the inorganic oxide used has a pH of from 1 to 6, an average particle diameter of from 5 to 200 &mgr;m, an average primary particle diameter of from 1 to 20 &mgr;M and voids or channels having an average diameter of from 0.1 to 20 &mgr;m and a macroscopic share of the volume of the overall particle within the range from 5 to 30%.

Abstract: Flame-retardant, thermoplastic molding materials containing A) at least one polyphenylene ether, B) at least one vinylaromatic polymer and C) at least one flameproofing agent, comprise D) an amount of expandable graphite which increases the resistance of the molding material to dripping and are used for the production of flame-retardant moldings, fibers and films.

Abstract: In catalyst systems of the Ziegler-Natta type modified during their preparation and comprising as active constituentsa) a titanium-containing solid component which is obtained by reacting a compound of titanium with a compound of magnesium, a halogen, an inorganic oxide as support, a C.sub.1 -C.sub.8 -alkanol and a carboxylic ester as electron donor compound,and also as cocatalystb) an aluminum compound andc) if desired, a further electron donor compound,the titanium-containing solid component a) is prepared by first, in a first stage, admixing an inorganic oxide as support with a solution of a chlorine-free compound of magnesium in an inert solvent, stirring this mixture for from 0.5 to 5 hours at from 10 to 120.degree. C. and subsequently reacting it while stirring continually in an inert solvent with a C.sub.1 -C.sub.8 -alkanol in an at least 1.

Abstract: Halogen-free antidrip agents for thermoplastic molding materials contain polymers based on vinylaromatic monomers and having molecular weights (M.sub.w) of at least 800 000 g/mol and a narrow molecular weight distribution.

Abstract: In catalyst systems of the Ziegler-Natta type comprising as active constituentsa) a titanium-containing solid component which is obtained by reacting a compound of titanium with a compound of magnesium, a halogen, an inorganic oxide as support, a C.sub.1 -C.sub.8 -alkanol and a carboxylic ester as electron donor compound,and also as cocatalyst,b) an aluminum compound andc) if desired, a further electron donor compound,the reaction of the individual components for preparing the titanium-containing solid component a) is carried out in the presence of an aromatic hydrocarbon as solvent.

Abstract: Polymers of C.sub.2 -C.sub.12 -alk-1-enes are prepared at from -50 to 300.degree. C. and from 0.5 to 3000 bar in the presence of a catalyst system by a process in which the catalyst system used is one which containsA) an inorganic or organic carrier,B) a metallocene complex,C) a compound forming metallocenium ions andD) if required, a metal compound of the general formula IM.sup.1 (R.sup.1).sub.r (R.sup.2).sub.s (R.sup.3).sub.t IwhereM.sup.1 is an alkali metal, an alkaline earth metal or a metal of main group III of the Periodic Table,R.sup.1 is hydrogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.15 -aryl, alkylaryl or arylalkyl, each having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,R.sup.2 and R.sup.3 are each hydrogen, halogen, C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.

Abstract: Catalyst systems of the Ziegler-Natta type comprising as active constituentsa) a titanium-containing solid component prepared using a titanium compound, a compound of magnesium, a halogenating agent and an electron donor component,b) an aluminum compound andc) as further electron donor component, an organosilicon compound of the formula (I)R.sup.1 R.sup.2 si(OR.sup.3).sub.2 (I)in whichR.sup.1 is a C.sub.1 -C.sub.10 -alkyl radical or a C.sub.3 -C.sub.8 -cycloalkyl radical, R.sup.2 is a 2,4,4,6,6-pentamethylheptyl radical andR.sup.3 is a C.sub.1 -C.sub.8 -alkyl radical,are particularly suitable for the preparation of polymers of C.sub.2 -C.sub.10 -alk-1-enes.