Abstract: Novel crystalline copolymers of propylene with minor proportions of ethylene and/or alpha-olefins, endowed with very good mechanical properties, a low melting point and a limited solubility in xylene at 25° C., and the process for preparing them by means of the polymerization of mixtures of propylene with ethylene and/or alpha-olefins of suitable composition, by using catalysts obtained from stereorigid and chiral compounds of zirconium, and methylalumoxanic compounds.

Abstract: Novel crystalline copolymers of propylene with minor proportions of ethylene and/or alpha-olefins, endowed with very good mechanical properties, a low melting point and a limited solubility in xylene at 25.degree. C., and the process for preparing them by means of the polymerization of mixtures of propylene with ethylene and/or alpha-olefins of suitable composition, by using catalysts obtained from stereorigid and chiral compounds of zirconium, and methylalumoxanic compounds.

Abstract: Disclosed are polymers and copolymers of CH.sub.2 .dbd.CHR alpha olefins where R is hydrogen or a 1-6 carbon atom alkyl radical, containing in the chain from 0.1 to 40 mole % of monomeric units ##STR1## where X is selected from the group consisting of (CH.sub.2).sub.r CH.sub.2 CH.sub.2 Y ##STR2## where r=0-10, Y is a halogen atom, R.sup.1 is a hydrocarbon radical with 1-18 carbon atoms.

Abstract: Highly crystalline high melting 1,5-hexadiene cyclopolymers are prepared by carrying out the polymerization in the presence of a catalyst comprising a specific Zr or Hf metallocene compound and specific alumoxane compounds.

Abstract: Essentially syndiotactic crystalline copolymers of propylene with minor proportions of 1-butene, endowed with good mechanical properties, lowered melting point and limited solubility in xylene at 25.degree. C. and the process for their preparation by polymerizing mixtures of propylene with 1-butene, by using catalysts obtained form stereorigid and chiral zirconium and hafnium compounds and from polymethylalumoxane compounds.

Abstract: A process for the production of primarily syndiotactic vinyl aromatic polymers by polymerizing or copolymerizing vinyl aromatic monomers such as styrene or styrene derivatives in the presence of a catalyst system comprising the product of the reaction between:a) a compound of a transition metal (M) different from titanium and containing at least a bond M-O, M-C, M-N, M-P, M-S or M-halogen, andb) an organoaluminum compound containing at least an oxygen atom bound to the aluminum atom or bound between two aluminum atoms.Compound a) can be used as such or may be supported on a suitable carrier.

Abstract: Acrylic diesters of bisphenol-alkyl-ether of formula: ##STR1## in which R.sub.1 and R.sub.2 may be a halogen or a C.sub.1 -C.sub.7 alkyl radical optionally halogen-substituted, and R.sub.3 may be hydrogen, halogen, or a C.sub.1 -C.sub.7 alkyl radical optionally halogen-substituted. Polymers obtained from the acrylic diesters of bisphenol-alkyl-ether of formula (1) and dental composites containing said acrylic diesters.

Abstract: Polymerization catalysts, more particularly catalysts for the polymerization of ethylene and mixtures thereof with other monomers copolymerizable therewith, are disclosed. The catalysts are prepared by mixing (A) an organometallic compound or hydride of a metal belonging to Groups I, II or III of the Mendelyeev Periodic Table, with (B) the reaction product of (1) a titanium compound of the type (NR.sub.4).sub.p Ti.sub.m X.sub.(n.m)+p, in which R.sub.4 is hydrogen and/or hydrocarbon radicals, X.sub.n.m represents halogen atoms or, in part, OR' groups in which R' is an organic radical; n represents the Ti valence, and m and p are the whole numbers 1, 2 or 3; and (2) a carrier comprising an anhydrous magnesium halide.

Abstract: New catalysts for the polymerization of olefins and more particularly of ethylene and mixtures thereof with higher alpha-olefins and/or diolefins, are disclosed. The catalysts are prepared by mixing (a) a hydride or an organo-metallic compound of a metal belonging to Groups I, II or III of the Mendelyeev Periodic Table with (b) the product obtained by contacting a titanium compound (1) with a mixture of an anhydrous magnesium halide (2) in a particular active form and an anhydrous compound of a metal belonging to Group I or II of said Periodic Table, (3). In the particular active form to which it is converted, during or prior to the contacting the anhydrous magnesium halide is characterized in that, in its X-ray spectrum, the diffraction line which is most intense in the X-ray spectrum of the normal, inactive magnesium halide shows a decreased intensity, and/or the active magnesium halide has a surface area greater than 3 m.sup.2 /g.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha-olefins or mixtures thereof with ethylene, conducted in the presence of highly active and stereospecific new catalysts. The catalysts are obtained from the reaction of a particular Al-alkyl compound which is at least in part in the form of a complex and/or a substitution reaction product with an ester of an oxygenated organic or inorganic acid, with a supported component characterized by having surface area exceeding certain values or showing a particular X-rays spectrum, and obtained by contacting a Ti halogenated compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn bihalide in an activated condition. In the catalysts the ratio between the Ti compound, expressed in Ti g-atoms, and the g moles of the ester and the electron-donor compound, when present, is lower than 0.3.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha olefins or mixtures thereof with ethylene conducted in the presence of highly active and stereospecific new catalysts. The catalysts are obtained from the reaction of a particular Al-alkyl compound which is at least in part in the form of a complex and/or a substitution reaction product with an electron-donor compound free from ester groups of oxygenated organic and inorganic acids, with a supported component characterized by having surface area exceeding certain values or by showing a particular X-rays spectrum and which is obtained by contacting a halogenated Ti compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn dihalide in an active state. In the catalysts the ratio between the Ti compound expressed in Ti g-atoms and the g-moles of the electron donor compounds is lower than 0.3.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha-olefins or mixtures thereof with ethylene, conducted in the presence of highly active and stereospecific new catalysts. The catalysts are obtained from the reaction of a particular Al-alkyl compound which is at least in part in the form of a complex and/or a substitution reaction product with an ester of an oxygenated organic or inorganic acid, with a supported component characterized by having surface area exceeding certain values or showing a particular X-rays spectrum, and obtained by contacting a Ti halogenated compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn bihalide in an activated condition.In the catalysts the ratio between the Ti compound, expressed in Ti g-atoms, and the g moles of the ester and the electron-doner compound, when present, is lower than 0.3.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha olefins or mixtures thereof with ethylene, conducted in the presence of highly active and stereospecific new catalysts. The catalysts are obtained from the reaction of a particular Al-alkyl compound which is at least in part in the form of a complex and/or a substitution reaction product with an ester of an oxygenated organic or inorganic acid, with a supported component characterized by having surface area exceeding certain values or by showing a particular X-rays spectrum, and obtained by contacting a Ti halogenated compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn bihalide.In the catalysts the ratio between the Ti compound, expressed in Ti g-atoms, and the g moles of the ester and the electron-donor compound, when present, is lower than 0.3.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha-olefins or mixtures thereof with ethylene, conducted in the presence of highly active and stereospecific new catalysts. The catalysts are obtained from the reaction of a particular Al-alkyl compound which is at least in part in the form of a complex and/or a substitution reaction product with an ester of an oxygenated organic or inorganic acid, with a supported component characterized by having surface area exceeding certain values or showing a particular X-rays spectrum, and obtained by contacting a Ti halogenated compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn bihalide.In the catalysts the ratio between the Ti compound, expressed in Ti g-atoms, and the g moles of the ester and the electron-donor compound, when present, is lower than 0.3.

Abstract: There is disclosed a process for the stereoregular polymerization of alpha olefins or mixtures thereof with ethylene conducted in the presence of highly active and stereospecific new catalysts.The catalysts are obtained from the reaction of a component (A) which is a particular Al-alkyl compound that is at least in part in the form of an addition and/or a substitution reaction product with an electron-donor compound free from ester groups of oxygenated organic and inorganic acids, with a component (B) which is a supported component characterized by having surface area exceeding certain values or by showing a particular X-rays spectrum, and prepared by contacting a halogenated Ti compound, preferably in the form of a complex with an electron-donor compound, with a support comprising a Mg or Mn dihalide in an active state.In the catalysts the ratio between the Ti compound expressed in Ti g-atoms and the g-moles of the electron-donor compounds is lower than 0.3.

Abstract: Alpha-olefins C.sub.3 -C.sub.6 are polymerized stereospecifically with the aid of catalysts obtained by mixing(a) a catalyst-forming component which is an addition and/or substitution product of an electron-donor compound (or a Lewis base) with an aluminum trialkyl, or an addition product of an electron-donor compound with an alkyl aluminum compound containing two or more Al - atoms bound to each other through an oxygen or nitrogen atom with(b) a supported catalyst-forming component which is the product obtained by contacting a titanium compound, preferably in the form of an addition product with an electron donor, with a carrier which is a mixture of an active anhydrous Mg or Mn dihalide and a solid organic material which is inert to all other components of the catalyst including the Mg or Mn dihalide carrier.