Versalis S.p.a.

Ecp Enichem Polimeri S.r.l.

Enichem Anic S.p.a.

Enichem S.p.a

Polimeri Europa S.p.a.

Francesco Menconi

Francesco Masi

Renzo Invernizzi

Angelo Moalli

Giuseppe Conti

Cesare Ferrero

Lia Barazzoni

Mario Polesello

Francesco Ciardelli

Stefano Malquori

Anna Sommazzi

Roberto Santi

Antonio Alfonso Proto

Nicoletta Cardi

Roberto Fusco

Laura Meda

Riccardo Po&prime;

Sergio Masini

Angelina Altomare

Federico Orsini

Tiziano Pennati

Corrado Adesso

Alberto Zanellato

Tiziano (deceased) Pennati

A precursor for the formation of catalysts for the (co)polymerization of &#x3b1;-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, obtained with a process comprising treatment with a siloxane compound. Said solid precursor, used in combination with a suitable co-catalyst in high-temperature (co)polymerization processes of &#x3b1;-olefins, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Catalyst precursor and catalyst for the high-temperature (co)polymerization of alpha-olefin

Catalyst and solid component of catalyst for the (co)polymerization of ethylene, comprising titanium, magnesium, chlorine, a protic organo-oxygenated compound Dand a neutral aprotic electron-donor compound D, in the following molar ranges: Mg/Ti=1.0-50; D/Ti=1.0-15; Cl/Ti=6.0-100; D/D=0.05-3; and a process for obtaining said component.

Solid catalyst component and process for the (co)polymerization of ethylene

Solid catalyst with a high thermal stability for the (co)polymerization of &#x3b1;-olefins, comprising titanium, magnesium, at least one metal selected from hafnium and zirconium, aluminum and chlorine, wherein at least 60% of the titanium is in oxidation state +3, and, when examined by means of XPS spectroscopy, has an absorption band characteristic of a binding energy ranging from 455 to 458 eV. Said catalyst, used in combination with a suitable co-catalyst in (co)polymerization processes of &#x3b1;-olefins at a high temperature, shows an improved productivity, a high incorporation of co-monomers in the copolymerization of ethylene and an increased thermal stability with respect to the systems so far in use.

Catalysts of the ziegler-natta type for the (co)polymerization of olefins with a high productivity

Solid component of catalyst for the (co) polymerization of ethylene and &agr;-olefins

Catalyst and process for the syndiotactic polymerization of vinylaromatic compounds

A solid component of catalyst highly active in the (co)polymerization of ethylene containing titanium, magnesium, aluminum, chlorine and alkoxy groups, and obtained by means of a procedure wherein:

Procedure for the preparation of a solid component of catalyst for the

Ethylene homopolymers and ethylene copolymers with alpha-(C.sub.3 -C.sub.10)-olefins are obtained by polymerizing the monomers with a polymerization catalyst formed by:

Process for polymerizing ethylene and copolymerizing ethylene with

A solid catalyst component for the low-pressure polymerization of ethylene and C.sub.3 -C.sub.10 alpha-olefins into very high molecular weight polyolefins is in the form of a spherical granular solid having a surface area of between 20 and 40 m.sup.2 /g, a mean pore radius of between 5,000 and 40,000 .ANG. and a porosity of between 40 and 90 vol %, and is definable by the following formula (in atomic proportions:

Catalyst component and catalyst for the production of very high

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Massa Macinaia, Italy

Francesco Menconi