Montedison S.p.a.

Montell Technology Company Bv

Montecatini Edison S.p.a.

Basell Technology Company B.v.

Himont Incorporated

Paolo Galli

Massimo Covezzi

Gabriele Govoni

Roberto Rinaldi

Italo Borghi

Giovanni Di Drusco

Sergio Foschi

Illaro Cuffiani

Umberto Zucchini

Paolo Parrini

Ermanno Susa

Adolfo Mayr

Ettore Giachetti

Giorgio Foschini

Mario Spataro

Saverio De Bartolo

Nicolino Fiscelli

Process for gas-phase polymerization carried out in two interconnected polymerization zones, to which one or more &agr;-olefins CH &boxH;CHR are fed in the presence of catalyst under reaction conditions and from which the polymer product is discharged. The process is characterized in that the growing polymer flows through a first polymerization zone under fast fluidization conditions, leaves said first zone and enters a second polymerization zone through which it flows in a densified form under the action of gravity, leaves said second zone and is reintroduced into the first polymerization zone, thus establishing a circulation of polymer around the two polymerization zones. The novel process allows olefins to be polymerized in the gas phase with high productivity per unit volume of the reactor without incurring the problems of the fluidized-bed technologies of the known state of the art.

Process and apparatus for the gas-phase polymerization of &agr;-olefins

Process for the gas-phase polymerization of olefins

Process for the gas-phase polymerization of ethylene and ethylene mixtures with .alpha.-olefins CH.sub.2 .dbd.CHR in the presence of a high activity catalyst comprising a titanium compound containing at least one Ti-halogen bond, supported on magnesium dichloride in active form said process comprising the steps of: (a) contacting the catalyst component; (b) prepolymerizing ethylene or ethylene mixtures with .alpha.-olefins in order to produce a polymer amount of from approximately 5 g per g of solid component, up to an amount corresponding to about 10% of the final catalyst yield; (c) polymerizing ethylene or ethylene mixtures with .alpha.-olefins in the gas-phase, in the presence of the prepolymer-catalyst system obtained in (b), while maintaining in the gas phase a molar concentration concentration of the alkane comprised between 20 and 90% with respect to the total gases.

Process for gas-phase polymerization carried out in two interconnected polymerization zones, to which one or more .alpha.-olefins CH.sub.2 .dbd.CHR are fed in the presence of catalyst under reaction conditions and from which the polymer product is discharged. The process is characterized in that the growing polymer flows through a first polymerization zone under fast fluidization conditions, leaves said first zone and enters a second polymerization zone through which it flows in a densified form under the action of gravity, leaves said second zone and is reintroduced into the first polymerization zone, thus establishing a circulation of polymer around the two polymerization zones. The novel process allows olefins to be polymerized in the gas phase with high productivity per unit volume of the reactor without incurring the problems of the fluidized-bed technologies of the known state of the art.

Process and apparatus for the gas-phase polymerization of .alpha.-olefins

Polyolefin fibers, which are suited for at least partially substituting the cellulose fibers in the manufacture of paper, are produced by a process which consists in preparing in a pressure vessel a solution of a polyolefin at a temperature higher than the boiling temperature of the solvent under normal conditions, and under autogenous pressure or a pressure greater than the autogenous pressure, in ejecting said solution under the above stated conditions into a zone of lower pressure, in allowing the ejected solution to expand at least partially in said zone, and in then hitting the at least partially expanded solution with a jet of a high-speed fluid, which is at a temperature lower than that of the solution, and has an angled direction with respect to the direction of ejection of the solution.

Process for the preparation of fibers from polymeric materials

Polypropylene compositions having high impact strength at low temperatures comprising as essential components:

Polypropylene compositions having improved impact strength properties at

There are disclosed components of catalysts for polymerizing ethylene and mixtures of ethylene with alpha-olefins comprising the reaction product of (A) a magnesium compound, such as Mg-chloride, Mg-alcoholate or a Grignard compound, with (B) a titanium, vanadium or zirconium compound having at least two metal-oxygen bonds, such as a tetra-alcoholate, and with (C) a halogenated compound of metals of B, such as Ti tetrachloride. According to an aspect of the invention, the reaction product (A)+(B), before being reacted with (C), is treated with a silicum compound having a halogenating and/or reducing action. The catalysts according to the invention are suitable for obtaining ethylene polymers having a broad distribution of molecular weights.

Catalyst components for polymerizing olefins

Thermoplastic rubbers comprising propylene-ethylene copolymers containing from 50% to 90% by weight of propylene and showing, on X-rays examination in the unoriented state, crystallinity of the polypropylene and/or polyethylene type are disclosed. Also disclosed is a method for preparing the thermoplastic rubbers by polymerizing mixtures of propylene and ethylene in the presence of a catalyst obtained by mixing

Thermoplastic rubbers and process for preparing same

Catalysts useful in the polymerization of olefins, more particularly of ethylene and mixtures thereof with higher alpha-olefins and/or diolefins, are disclosed. The new catalysts are obtained by mixing a hydride or organometallic compound of a metal belonging to Groups I to III of the Mendelyeev Periodic System with the product obtained by contacting a titanium tetrahalide with a support comprising an anhydrous magnesium or zinc halide in an active form, under particular conditions.

Catalysts for the polymerization of olefins

Thermoplastic rubbers comprising propylene-ethylene copolymers containing from 50% to 90% by weight of propylene and showing, on X-rays examination in the unoriented state, crystallinity of the polypropylene and/or polyethylene type are disclosed. Also disclosed is a method for preparing the thermoplastic rubbers by polymerizing mixtures of propylene and ethylene in the presence of a catalyst obtained by reacting.

Supported catalysts for the high-yield polymerization of olefins to polymers which occur in spheroidal form are disclosed. The catalysts are prepared from starting components which comprise (a) organometallic compounds of metals belonging to Groups II or III of the Mendelyeev Periodic Table and (b) a product obtained by reacting a halogenated Ti compound with a Mg hydrate chloride in the form of spheroidal particles having controlled dimensions comprised between 10 and 70 microns.

Catalysts for polymerizing olefins to spheroidal-form polymers

There are disclosed highly active supported catalysts for the polymerization of olefins to polymers in the form of spheroidal particles which neither break nor cake when subjected to compression. The supported catalysts are prepared by mixing

Growing community of inventors

Ferrara, Italy

Paolo Galli