摘要:
Ethylene based polymers having high molecular weights can be obtained in high yields at temperatures of industrial interest, by carrying out the polymerization reaction in the presence of catalysts comprising silicon bridged metallocenes having a particular ligand system containing a heteroatom.
摘要:
Metallocene compounds having the general formula (I): 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; M′ is a transition metal selected from those belonging to group 3 or to the lanthanide or actinide groups in the Periodic Table; X is a monoanionic ligand; p is an integer of from 0 to 3, being equal to the oxidation state of 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 formula (Ia) are not perhydrated, and is an integer of from 0 to 4, when the six-membered rings of formula (Ia) are perhydrated as well as in the compound of formula (Ib).
摘要:
Supported catalysts for the polymerization of olefins comprise the following components: (A) a porous organic support functionalised with groups having active hydrogen atoms; (B) an organo-metallic compound of aluminium containing heteroatoms selected from oxygen, nitrogen and sulphur; and (C) a compound of a transition metal selected from those of groups IVb, Vb or VIb of the Periodic Table of the Elements, containing ligands of the cyclopentadienyl type. These supported catalysts, obtainable in the form of spherical particles, can be used in the polymerization reaction of olefins either in liquid or in gas phase, thus producing polymers endowed with a controlled morphology and with a high bulk density.
摘要:
It is disclosed a new catalyst system for the polymerization of olefins comprising the product obtainable by contacting the following components: (A) one or more compounds of a late transition metal belonging to Group 8-11 of the Periodic Table; and (B) the reaction product of water with one or more organometallic aluminum compounds of formula (IV): Al(CH2—CR3R4R5)xR6yHz, wherein R3 is a C1-C20 alkyl, C3-C20 cycloalkyl or C7-C20 alkylaryl radical; R4 is different from a straight alkyl and is a C3-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; or R3 and R4 form together a C4-C6 ring; R5 is hydrogen or a C1-C20 alkyl, C6-C20 aryl, C7-C20 alkylaryl or arylalkyl radical; R6 is a C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C7-C20 alkylaryl or C7-C20 arylalkyl radical; x is 1-3; z is 0-1; and y is 3−x−z; the molar ratio between said organometallic aluminum compound and water being comprised between 0.5:1 and 100:1.
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.
摘要:
Ethylene copolymers are prepared with comonomers selected from:(a) .alpha.-olefins,(b) cycloolefins and(c) polyenes,with a content of ethylene units of between 80 and 99 mol %, a content of units derived from .alpha.-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.degree. C., and(b) M.sub.w /M.sub.n >3, where M.sub.w is the weight-average molecular weight and M.sub.n is the number-average molecular weight, both determined by means of GPC.
摘要:
Catalysts component of the (co)polymerization of alpha-olefins CH.sub.2 .dbd.CHR, wherein R is hydrogen or an alkyl radical having from 1 to 8 carbon atoms, comprising a product of the composition:VCL.sub.y.z(b)wherein (b) represents an organic compound selected from alkyl, aryl and acyl halides, y is a number higher than 2 and lower than 4, and preferably comprised between 2.5 and 3.5 and z is a number higher than zero and lower than or equal to 2, and preferably between 0.002 and 1. Components can be obtained as products of the reaction, carried out at temperatures higher than 10.degree. C., between VCl.sub.4 and the compound (b). Particularly preferred among compounds (b) are benzoyl chloride, p-methoxybenzoyl chloride and p-chloro benzoyl chloride. From the components of the invention, either supported or not, catalysts having high activity particularly useful for the production of ethylene polymers showing broad molecular weight distribution can be prepared.
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(CH.sub.2 --CR.sup.4 R.sup.5 R.sup.6).sub.w R.sup.7.sub.y H.sub.z(II) wherein in the (CH.sub.2 --CR.sup.4 R.sup.5 R.sup.6) groups, which are the same or different, R.sup.4 is an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, R.sup.5 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.sup.4 and R.sup.5 fused together can form a ring having from 4 to 6 carbon atoms, R.sup.6 is hydrogen or an alkyl, alkenyl or arylalkyl group having from 1 to 10 carbon atoms, the R.sup.7 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:
Multistage process for the polymerization of one or more olefins of the formula CH.sub.2 .dbd.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:
A catalyst component comprising Ti, Mg, Cl, and optionally ORI groups in which RI is a C1-C20 hydrocarbon group up to an amount such as to give a molar ORI/Ti ratio lower than 0.5, characterized by the following properties: surface area, determined by BET method, of lower than 80 m2/g, a total porosity (PT), measured by the mercury method, in the range of 0.60-1.50 cm3/g a difference (PT−PF) of higher than 0.1 in which PT is the total porosity and PF is the porosity due to pore with radius equal to or less than 1 μm; an amount of Ti in the catalyst component of less that 10% wt based on the total weight of catalyst component. The said catalyst components show high morphological stability under the low molecular weight ethylene polymerization conditions while at the same time maintaining characteristics of high activity.