摘要:
A process for preparing a broad molecular weight polyethylene carried out in the presence of a catalyst system comprising (i) a solid catalyst component comprising Mg, Ti, halogen, and optionally an internal electron donor compound, and (ii) an Al-alkyl cocatalyst said process comprising at least two step of polymerization (a) and (b), in which: in a first step (a) ethylene is polymerized in the presence of a molecular weight regulator in order to produce a ethylene (co)polymer, and in a further step (b), which is carried out in the presence of an external electron donor compound added to this polymerization step as a fresh reactant, ethylene is copolymerized with an alpha olefin of formula CH2═CHR, in which R is a C1-C20 hydrocarbon group, to produce an ethylene copolymer having a molecular weight higher than that of the copolymer produced in step (b).
摘要:
A process for preparing a broad molecular weight polyethylene carried out in the presence of a catalyst system comprising (i) a solid catalyst component comprising Mg, Ti, halogen, and optionally an internal electron donor compound, and (ii) an Al-alkyl cocatalyst said process comprising at least two step of polymerization (a) and (b), in which: in a first step (a) ethylene is polymerized in the presence of a molecular weight regulator in order to produce a ethylene (co)polymer, and in a further step (b), which is carried out in the presence of an external electron donor compound added to this polymerization step as a fresh reactant, ethylene is copolymerized with an alpha olefin of formula CH2═CHR, in which R is a C1-C20 hydrocarbon group, to produce an ethylene copolymer having a molecular weight higher than that of the copolymer produced in step (b).
摘要:
Solid adducts comprising a MgCl2, ethanol and a compound (A), said compounds being present in molar ratios defined by the following formula MgCl2.(EtOH)n(A)p in which n is from 0.1 to 6, p ranges from 0.001 to 0.5 and A is a compound selected from cyclic hydrocarbon structures which are substituted with at least two hydroxy groups.
摘要:
Catalyst precursors comprising Mg, Cl, Ti, and OR groups that are in molar ratios defined by the formula MgClnTip(OR)(2-n)+4p in which n is from 0.3 to less than 1.7, p is lower than 0.6, the molar ratio (OR)/Cl is lower than 4 and R is C1-C15 hydrocarbon groups. The said precursor, just upon activation with organo-Al compounds, are able to advantageously polymerize ethylene and alpha olefins, and that upon reaction with halogenating compounds generate in high yields catalyst components with high polymerization activity particularly in the polymerization of propylene also in combination with 1,3-diethers.
摘要:
Disclosed is a process for making a linear low density polyethylene (LLDPE) having low gels. The process comprises copolymerizing ethylene with one or more C3-10 α-olefins to produce an LLDPE resin which has a gel defect area less than 25 ppm. The copolymerization is performed in the presence of a Ziegler-Natta catalyst which comprises an MgCl2 support, a Ti(IV) complex, and a cyclic ether as an internal electron donor. The Ziegler-Natta catalyst has an Mg/Ti molar ratio greater than or equal to 7.
摘要:
Catalyst component for the polymerization of olefins CH2═CHR in which R is hydrogen or a hydrocarbyl radical with 1-12 carbon atoms, comprising Mg, Ti, halogen and two electron donor compounds one of which selected from alkoxybenzenes and the other being selected from those of formula (II) where RI and RII are the same or different and are hydrogen or linear or branched C1-C18 hydrocarbon groups which can also form one or more cyclic structures; RIII groups, equal or different from each other, are hydrogen or C1-C18 hydrocarbon groups; RIV groups equal or different from each other, have the same meaning of RIII except that they cannot be hydrogen; each of RI to RIV groups can contain heteroatoms selected from halogens, N, O, S and Si.
摘要:
Catalyst component for the polymerization of olefins comprising Mg, Ti, halogen and two electron donor compounds one of which selected those of formula (I) and the other being selected from succinates of formula (II):
摘要:
A catalyst component comprising Ti, Mg, Al, Cl, and optionally ORI groups in which RI is a C1-C20 hydrocarbon group, optionally containing heteroatoms, up to an amount such as to give a molar ORI/Ti ratio lower than 0.5, characterized by the fact that substantially all the titanium atoms are in valence state of 4, that the porosity (PF), measured by the mercury method and due to pores with radius equal to or lower than 1 μm, is at least 0.3 cm3/g, and by the fact that the Cl/Ti molar ratio is lower than 29.The said catalysts are characterized by high morphological stability under the low molecular weight ethylene polymerization conditions while at the same time maintaining characteristics of high activity.
摘要:
A method for preparing a titanium-containing Ziegler-Natta catalyst is disclosed. A dialkyl magnesium compound, a trialkyl aluminum compound, and a polymethylhydrosiloxane are first combined in a hydrocarbon solvent. That product is then combined with dry, alcohol-free magnesium chloride. A solid product from the reaction with the magnesium chloride component is isolated and washed with a hydrocarbon solvent. The washed solid product is then combined with an alkyl aluminum dichloride or a dialkyl aluminum chloride to give the catalyst. The catalyst is suitable for both slurry and gas-phase olefin polymerizations. Polyolefins produced with the catalyst have broad molecular weight distributions and narrow distributions of relatively large particles.
摘要:
A solid catalyst component for olefin polymerization, and in particular for the preparation of LLDPE, comprising Mg, Ti, halogen and an electron donor compound (ID) belonging to cyclic ethers having 3-6 carbon atoms, characterized by having the molar ratio Mg/Ti higher than 5, the molar ratio Mg/ID lower than 3, and by a specific X-ray diffraction spectrum.