Abstract: A process for polymerizing olefins at temperatures of from 30° C. to 140° C. and pressures of from 1.0 MPa to 10 MPa in the presence of a polymerization catalyst in a multistage polymerization of olefins in at least two serially connected gas-phase polymerization reactors, and apparatus for the multistage polymerization of olefins, comprising at least two serially connected gas-phase polymerization reactors and a device for transferring polyolefin particles from an up-stream gas-phase polymerization reactor to a downstream gas-phase polymerization reactor, the transferring device comprising—a gas/solid separation chamber placed downstream of the upstream gas-phase polymerization which gas/solid separation chamber is equipped at a lower part with an net for introducing a fluid, and—connected to the gas/solid separation chamber at least two lock hoppers, placed in a parallel arrangement, each connected to the downstream gas-phase polymerization reactor.

Abstract: A process for polymerizing olefins in at least two serially connected gas-phase polymerization reactors, the process for transferring polyolefin particles from a first gas-phase polymerization reactor to a second gas-phase polymerization reactor comprising the steps of: a) discharging polyolefin particles into a separation chamber being at a lower pressure than the pressure in the first reactor; b) transferring the polyolefin particles within the separation chamber into a lower part which contains a bed of polyolefin particles which moves from top to bottom of this part of the separation chamber and into which a fluid is introduced so that an upward fluid stream is induced, c) withdrawing polyolefin particles from the lower end and transferring them to one of at least two lock hoppers working intermittently in parallel; and d) simultaneously pressurizing another of the at least two lock hoppers working intermittently by means of a gas comprising reaction gas coming from the second reactor.

Abstract: Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [?] values in tetrahydronaphthalene at 135° C.?2.8 dl/g, mW/MN values>20, a fraction insoluble in xylene at 25° C.?94, and including from 10 to 60% by weight of a fraction (A) having [?]?2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of a particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.

Abstract: Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [?] values in tetrahydronaphthalene at 135° C.?2.8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.?94, and including from 10 to 60% by weight of a fraction (A) having [?]?2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of a particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.

Abstract: Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [?] values in tetrahydronaphthalene at 135° C.?2/8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.?94, and including from 10 to 60% by weight of a fraction (A) having [?]?2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of particular Ziegler-Natta catalysts supported on magnesium halides. These polymers have high melt strength, high mechanical properties, and are particularly adequate for the manufacture of articles by using various conversion technologies, such as for example extrusion in thin sheets to be subjected to thermoforming, as well as for injection molding, and blow molding.

Abstract: Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [&eegr;] values in tetrahydronaphthalene at 135° C.≦2.8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.≧94, and comprising from 10 to 60% by weight of a fraction (A) having [&eegr;]≧2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of particular Ziegler-Natta catalysts supported on magnesium halides.

Abstract: Crystalline polymers and copolymers of propylene having total MIL values>2 g/10 minutes, total [&eegr;] in values in tetrahydronaphthalene at 135° C.≦2.8 dl/g, Mw/Mn values>20, a fraction insoluble in xylene at 25° C.≧94, and comprising from 10 to 60% by weight of a fraction (A) having [&eegr;]≧2.6, are prepared by way of sequential polymerization in at least two stages, in the presence of particular Ziegler-Natta catalysts supported on magnesium halides.

Abstract: Disclosed is a polymer composition containing:(A) from 70 to 98 parts by weight of a crystalline propylene homopolymer, or a crystalline random copolymer of propylene with ethylene and/or C.sub.4 -C.sub.10 .alpha.-olefins, containing from 0.5 to 10% by weight of ethylene and/or .alpha.-olefins [fraction (A)]; and(B) from 2 to 30 parts by weight of elastomeric copolymer of ethylene with one or more C.sub.4 -C.sub.10 .alpha.-olefins, containing from 60 to 85% by weight of ethylene, and partially soluble in xylene at 25.degree. C. [fraction (B)];wherein the composition has an intrinsic viscosity value in tetrahydronaphthalene at 135.degree. C. of the fraction soluble in xylene at 25.degree. C. ranging from 0.8 to 1.1 dl/g.

Abstract: Disclosed are polyolefin compositionshaving high balance of stiffness and impact strength, which comprise (percentage by weight):A) 30%-60% of a propylene homopolymer or copolymer;B) 14%-30% of a fraction comprising copolymers of propylene with ethylene;C) 10%-25% of a copolymer of ethylene with a C.sub.3 -C.sub.8 .alpha.-olefin;D) 5%-45% of a mineral filler.

Abstract: Discosed are compositions of crystalline propylene polymers comprising (by weight):A) 30-65% of a copolymer of propylene with a C.sub.4 -C.sub.8 .alpha.-olefin, containing from 98 to 80% propylene;B) 35-70% of a copolymer of propylene with ethylene and optionally from 2 to 10% of a C.sub.4 -C.sub.8 .alpha.-olefin, said copolymer containing 2 to 10% ethylene when the C.sub.4 -C.sub.8 .alpha.-olefin is not present, and 0.5 to 5% ethylene when the C.sub.4 -C.sub.8 .alpha.-olefin is present.

Abstract: Crystalline polymers and copolymers of propylene in the form of spherical particles having a porosity (expressed in percentage of voids) greater than 15%. These polymers are useful in the preparation of masterbatch containing significant quantities of additives and/or pigments.

Abstract: Crystalline olefin polymers and copolymers in the form of spherical particles having porosity (expressed in percentage of voids) higher than 15%, with more than 90% of the pores having a pore diameter greater than one micron. These polymeric particulate materials find many applications, including, e.g., the preparation of masterbatches containing significant quantities of additives and/or pigments.