摘要:
A class of metallocene compounds is disclosed having general formula (I) or (Ib): wherein R1 are hydrocarbon groups; R2 are hydrogen or hydrocarbon groups, M is a transition metal of group 3, 4, 5, 6 or to the lanthanide or actinide groups in the Periodic Table of the Elements (new IUPAC version), M' is transition metal selected from those belonging to group 3 or to the lanthanide or actinide groups in the Periodic Table of the Elements (new IUPAC version), X is a monoanionic ligand, p is an integer of from 0 to 3, being equal to the oxidation state of the metal M minus two, q is an integer from 3 to 5, and n is an integer from 1 to 4, when the six-membered rings of the compound of formula (Ia) are not perhydrated, and is an integer for from 0 to 4, when the six-membered rings of the compound of formula (Ia) are perhydrated as well as in the compound of formula (Ib). These metallocenes are useful as catalyst components for the polymerisation of olefins.
摘要:
Catalysts for the polymerization of olefins are disclosed, which comprise the reaction product of: (A) a bridged and/or substituted cyclopentadienyl compound of titanium, zirconium or hafnium; (B) an organometallic aluminum compound of the formula (II) Al(CH2-CR4R5R6)wR7yHz, wherein in the (CH2-CR4R5R6) groups, which are the same or different, R4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R5 is an alkyl, alkenyl, aryl, arylalkyl or alkylaryl group having from 3 to 50 carbon atoms which is different from a straight alkyl or alkenyl group and, optionally, R?4 and R5¿ fused together can form a ring having from 4 to 6 carbon atoms, R6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, the R7 substituents, same or different, are alkyl, alkenyl, aryl, arylalkyl or alkylaryl radicals containing from 1 to 10 carbon atoms and, optionally, can contain Si or Ge atoms, w is 1, 2 or 3, z is 0 or 1, y = 3-w-z; and (C) water. The molar ratio aluminum/water is comprised between 1:1 and 100:1. These catalysts show an improved activity with respect to known catalysts wherein an aluminum compound different from those of the above formula is used.
摘要:
Ethylene based copolymers having high molecular weights, narrow molecular weight distributions, and a very good homogeneous distribution of the comonomer units can be obtained in high yields at temperatures of industrial interest, by carrying out the polymerization reaction in the presence of metallocene catalysts comprising particular bridged bis-indenyl compounds substituted in the 3-position on the indenyl groups.
摘要:
Catalysts for the polymerization of olefins are disclosed, comprising the product obtainable by contacting: (A) a bridged and/or substituted cyclopentadienyl compound of Ti, Zr or Hf; (B) one or more organometallic aluminium compounds of formula (II): A1R43-zHz wherein the substituents R4, same or different from each other, are linear or branched, saturated or unsaturated C¿1?-C20 alkyl or alkylaryl radicals, optionally containing Si or Ge atoms, wherein at least one of the substituents R?4¿ is different from a straight alkyl group; z is 0 or 1; and (C) water; the molar ratio between the organometallic aluminium compound and water being comprised between 1:1 and 100:1; said catalyst being obtainable by a process comprising the following steps: (i) contacting component (A) with part of component (B) in the absence of component (C); (ii) contacting part of component (B) with component (C) in the absence of component (A) and successively (iii) contacting the products obtained in steps (i) and (ii).
摘要:
Multistage process for the polymerization of one or more olefins of the formula CH2=CHR, in which R is hydrogen or an alkyl, cycloalkyl or aryl group having from 1 to 10 carbon atoms, comprising: (A) a first stage of polymerization, in which a first olefin polymer is prepared in the presence of titanium catalyst or vanadium catalyst; (B) a treatment stage in which the catalyst used previously is deactivated and in which a metallocene compound is supported on the olefin polymer produced in stage (A); and (C) a second stage of polymerization in which one or more olefins are polymerized in the presence of the product obtained from stage (B).
摘要:
Ethylene copolymers are prepared with comonomers selected from (a) α-olefins, (b) cycloolefins and (c) polyenes, with a content of ethylene units of between 80 and 99 mol %, a content of units derived from α-olefin, cycloolefin and/or polyene comonomers of between 1 and 20 mol %, characterized in that: (a) in TREF (Temperature Rising Elution Fractionation) analysis, a quantity equal to at least 90 % by weight of the copolymer is eluted within a temperature interval of less than 50 °C, and (b) Mw/Mn > 3, where Mw is the weight-average molecular weight and Mn is the number-average molecular weight, both determined by means of GPC.
摘要:
A class of bridged or unbridged metallocene compounds is disclosed, wherein the cyclopentadienyl ligands have two or four adjacent substituents forming one or two alkylenic cycles of from 4 to 8 carbon atoms. These metallocenes are useful as catalyst components for the polymerization of olefins, particularly for the (co)polymerization of ethylene and for the polymerization of propylene.