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: Metallocene catalyst systems for the polymerization of C.sub.2 -C.sub.10 -alkenes are obtainable by deactivation of a preactivated metallocene catalyst system which contains, as active components, a metallocene complex of a metal of subgroup IV or V of the Periodic Table and an oligomeric alumoxane compound and, if required, subsequent reactivation.

Abstract: Propylene-ethylene copolymers are obtained by two-stage polymerization from the gaseous phase in an agitated fixed bed by means of a Ziegler-Natta catalyst system that contains in addition to a titanium-containing solid component also an aluminum compound as co-catalyst, wherein as Ziegler-Natta catalyst system a system is used which, following the reaction of the titanium-containing solid component with the co-catalyst, is deactivated by reaction with carbon dioxide. The copolymers are used for producing fibers, films and moldings.

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 as electron donor,b) an aluminum component,c) a further electron-donor component, and, as an additional component,d) an organometallic compound of the general formula A or B ##STR1## where M.sup.1 is an element f rom main group I, and M.sup.2 is an element from main group II of the Periodic Table, and R.sup.1 and R.sup.2 are identical or different C.sub.1 -C.sub.10 -alkyl, C.sub.6 -C.sub.12 -aryl, C.sub.6 -C.sub.12 -arylalkyl, or 5- to 7-membered cycloalkyl, which may itself carry C.sub.1 -C.sub.8 -alkyl groups,can be used to prepare polymers which have, in particular, a low proportion of very fine grains.

Abstract: Thermoplastic molding materials obtained from polymers based on vinyl chloride contain from 2 to 80% by weight of a polymer ofa) from 2 to 100% by weight of a monomer of the general formula I ##STR1## where R.sup.1 is hydrogen or C.sub.1 -C.sub.4 -alkyl and Ar is an isoaromatic group, or of a mixture of these monomers, andb) from 0 to 98% by weight of a monomer of the general formula II ##STR2## where R.sup.2 is C.sub.1 -C.sub.4 -alkyl and Alk is C.sub.1 -C.sub.8 -alkyl, or of a mixture of these monomers, andc) from 0 to 5% by weight of further monomers capable of undergoing free radical polymerization (monomers III).The molding materials have a high heat distortion resistance.