Abstract: Propylene polymers contain a) from 50 to 95 parts by weight of a propylene homopolymer having a melt flow index of from 0.1 to 100 g/10 min., at 230° C. and under a weight of 2.16 kg, according to ISO standard 1133, and an isotacticity index of at least 98%, b) from 5 to 50 parts by weight of an ethylene copolymer containing from 4 to 40% by weight of polymerized C4-C20-alk-1-ene and having a density of from 0.865 to 0.920 g/cm3 and c) from 0 to 1.5 parts by weight of a nucleating agent, the sum of the parts by weight of the propylene homopolymer a) and of the ethylene copolymer b) always being 100 parts by weight. The propylene polymers are distinguished in particular by high rigidity and little tendency to white fracture.

Abstract: Polymers of propene consist of from 50 to 99.9% by weight of an isotactic propene copolymer (A′) and from 0.1 to 50% by weight of a propene homopolymer or a propene copolymer (B′), where a) the propene copolymer (A′) consists of from 80 to 99.9 mol % of propene and from 0.1 to 20 mol % of ethene and/or a C4-C12-1-olefin, at least 80% of all propene diads are isotactic meso diads, the propene copolymer (A′) has a proportion (XS) of material soluble in xylene at 20° C. which satisfies the inequality (1) (XS)<542 400 exp (−0.1TM)+0.5  (1),  the tensile modulus of elasticity (E) of the propene copolymer (A′) in MPa, determined in accordance with ISO 527, obeys the inequality (2) (E)>1.9×10−11(TM)6.34+180 MPa  (2),  where in both inequalities (1) and (2) TM is the melting point in ° 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: A partially crosslinked polymer composition having a melt flow index of from 0.1 to 50 g/10 min at 230.degree. C. under a weight of 2.16 kg and comprisinga) a polymer comprising from 25 to 95% by weight of polypropylene and 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) 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, obtainable by reacting the polymer a) with the organosilane compound b) in the presence of a free-radical initiator and in the presence of a condensation catalyst at from 180.degree. to 280.degree. C., and at from 1 to 100 bar and at a mean residence time of the reaction mixture of from 0.

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 recyclable bumper system based on polypropylene comprises a bumper support A of glass fiber reinforced polypropylene, an energy-absorbing foam core B of foamed polypropylene and a tough shell C of EP-rubber modified polypropylene which may be coated, and can be recycled by mechanical comminution, extrusion and granulation, resulting in granules from which injection moldings having good mechanical properties can be produced.

Abstract: Propylene/ethylene block copolymers are prepared by a continuous process in which, in each case in an agitated fixed bed of finely divided polymer from the gas phase, first (I) in a first polymerization zone, propylene is homopolymerized by feeding in a Ziegler-Natta catalyst system consisting of (1) a titanium component which contains titanium, magnesium, chlorine and a phthalic acid derivative, (2) an aluminumalkyl component and (3) a silane component, and (II) in a second polymerization zone, a mixture of propylene and ethylene is polymerized with the propylene homopolymer present in the reaction mixture obtained in the first polymerization zone by feeding in the said reaction mixture. In the process, (A) a titanium component (1) is used which is obtained by a method in which (1.1) first, (1.1.1) in a liquid hydrocarbon, (1.1.2) a finely divided magnesium halide, (1.1.3) an alkanol, (1.1.4) a certain phthalic acid derivative and (1.1.