摘要:
Disclosed is a method for making LLDPE grades having different xylene solubles or hexane extractables with the same Ziegler-Natta catalyst by varying the amount of alkylaluminum used for polymerization. The method comprises copolymerizing ethylene with a C3-10 α-olefin in the presence of a Ziegler-Natta catalyst, an alkylaluminum, and an electron donor; determining the dependency of the xylene solubles or hexane extractables on the alkylaluminum/electron donor ratio; and adjusting the alkylaluminum/electron donor ratio to achieve a desired xylene solubles or hexane extractables.
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:
Process for the preparation of ethylene polymers having narrow MWD characterized by a F/E ratio lower than 35 carried out in the presence of a catalyst system comprising (a) a solid catalyst component comprising Ti atoms that are substantially in the +4 oxidation state, Mg, Cl, and optionally OR groups and internal donors in which R is a C1-C20 hydrocarbon group, in which the OR/Ti molar ratio is equal to or lower than 0.35 and the internal donor/Ti ratio is lower than 1, (b) an aluminum alkyl compound and (c) a compound selected from alkoxybenzenes of specified formula.
摘要:
A process for the (co)polymerization of propylene carried out at a temperature ranging from 77 to 95° C. in the presence of a catalyst comprising the product obtained by reacting: —an organo-aluminium compound, with—-a solid catalyst component comprising Mg, Ti and electron donor compound selected from specific diolesters.
摘要:
A pre-polymerized catalyst component for the polymerization of olefins CH2═CHR, wherein R is hydrogen or a C1-C12 hydrocarbon group, characterized by comprising a non-stereospecific solid catalyst component, comprising Ti, Mg and a halogen, said pre-polymerized catalyst component containing an amount of a (co)polymer of a monomer having formula CH2═CHA, where A is a C6 aliphatic or aromatic ring, optionally substituted, up to 5 g per g of said solid catalyst component. Said prepolymerized catalyst shows an excellent balance in terms of activity, morphological stability, reduced tendency to agglomeration and hydrogen response.
摘要:
A porous solid catalyst component comprising a magnesium halide, a titanium compound having at least a Ti-halogen bond and at least two electron donor compounds one of which being selected from 1,3-diethers and the other being selected from succinates, characterized by the fact that the molar ratio ID/Ti is from 0.30 to 0.90, where ID is the total molar amount of succinate and 1,3-diether, the molar ratio of the 1,3-diether donor to the succinate donor is higher than, or equal to, 0.60.
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:
A modified Ziegler-Natta catalyst system, a method for preparing the catalyst system, and a process for polymerizing an olefin in the presence of the catalyst system are disclosed. The catalyst system comprises a titanium or vanadium compound, an aluminum compound, and a pyridazine. Improved properties such as increased molecular weight and narrowed molecular weight distribution are obtained.
摘要:
A modified Ziegler-Natta catalyst system, a method for preparing the catalyst system, and a process for polymerizing an olefin in the presence of the catalyst system are disclosed. The catalyst system comprises a titanium or vanadium compound, an aluminum compound, and an indazole. Improved comonomer incorporation and the ability to regulate molecular weight are achieved in the manufacture of polyolefins.
摘要:
A catalyst system comprising the product obtained by contacting (a) a solid catalyst component containing Mg, Ti, halogen and at least an electron donor compound selected from diolesters of a specific formula (b) an alkylaluminum cocatalyst and (c) an ester of formula R′OOC—(CR″2)m—COOR′ in which m is an integer from 2 to 8, the R′ groups, equal to or different from each other, are C1-C10 alkyl groups and the R″ groups, independently, are hydrogen or C1-C15 hydrocarbon groups.