Abstract:
The present invention relates to a slurry process for preparing an ethylene polymer having a melt flow ratio F/P, which is the ratio among the melt index value measured according to ASTM 1238 condition "F" and the melt index value measured according to ASTM 1238 condition "P" of equal to or lower than 27, carried out in two or more stages of polymerization at temperatures in the range from 60 to 120°C, in which at least two of the said two or more polymerization stages are carried out under different amounts of molecular weight regulator, said process being carried out in the presence of (A) a solid catalyst component comprising Ti, Mg, halogen, having a porosity (P F ), measured by the mercury method and due to pores with radius equal to, or lower than, 1µm, of at least 0.3 cm 3 /g and a surface area determined by BET method, of lower than 100 m 2 /g, and being further characterized by the fact that more than 50% of the titanium atoms are in a valence state lower than 4 and (B) of an organoaluminum compound.
Abstract:
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.
Abstract:
Catalyst component comprising Mg, Ti, and halogen atoms, and is characterized in that (a) the Ti atoms are present in an amount higher than 4% based on the total weight of the said catalyst component, (b) the amount of Mg and Ti atoms is such that the Mg/Ti molar ratio is higher than 2 and (c) by a X-ray diffraction spectrum, in which, in the range of 2θ diffraction angles between 47° and 52°, at least two diffraction lines are present at diffraction angles 2θ of 48.3 ± 0.2°, and 50.0 ± 0.2°, the most intense diffraction lines being the one at 2θ of 50.0 ± 0.2°, the intensity of the other diffraction line being equal to or lower than the intensity of the most intense diffraction line.
Abstract:
Prepolymerized catalyst component for the polymerization of olefins CH 2 =CHR, wherein R is hydrogen or a C 1 -C 12 hydrocarbyl group, comprising a solid catalyst component characterized by comprising Mg, Ti halogen and an electron donor (ID) selected from the alkyl esters of aromatic dicarboxylic acids in such an amount that the molar ratio ID/Mg ranges from 0.025 to 0.07 and the Mg/Ti molar ratio is higher than 13, said prepolymerized catalyst component containing an amount of ethylene pre-polymer up to 5Og per g of said solid catalyst component.
Abstract:
Catalyst component for the polymerization of olefins comprising Mg, Ti, halogen and an electron donor is obtained by a batch process comprising: (A) A first step comprising reacting an adduct of formula MgCl2(ROH)n, where R is a C1-C10 alkyl group, and n is from 0.5 to 6, in a liquid medium comprising a titanium compound having at least a Ti-Cl bond at a temperature ranging from 0°C to 80°C and then removing the liquid medium; (B) A subsequent step comprising reacting the solid product obtained in (A) in a liquid medium comprising an electron donor ED selected from ethers, esters, ketones, silanes, amines, nitriles and amides, and a titanium compound having at least a Ti-Cl bond at a temperature higher than 80°C and then, after removing the liquid medium; (C) A subsequent step comprising reacting the solid product coming from (B) with a liquid medium comprising a titanium compound having at least a Ti-Cl bond at a temperature higher than 80°C.
Abstract:
Catalyst components for the polymerization of olefins comprising Mg, Ti, halogen and 1,3- diethers as internal donors having an improved balance of properties in terms of activity and morphological stability are obtained by a process comprising: (A) A first step comprising reacting an adduct of formula MgC12(ROH)n, where R is a C1-C10 alkyl group, and n is from 0.5 to 6, with a titanium compound having at least a Ti-C1 bond at a reaction temperature ranging from 0°C to 80°C; (B) A subsequent step comprising contacting the solid product obtained in (A) with an electron donor ED selected from 1,3 diethers with a titanium compound having at least a Ti-C1 bond at a temperature higher than 80°C; and (C) A subsequent step comprising reacting the solid product coming from (B) with a titanium compound having at least a Ti-C1 bond at a temperature higher than 80°C.
Abstract:
The present invention relates to a MgCl2•mEtOH adduct in which m is from 2.5 to 3.2 optionally containing water up to a maximum of 1%wt based on the total weight of the adduct, characterized by a DSC profile in which the highest melting Temperature (Tm) peak is over 109°C and has an associated fusion enthalpy ( H) of 103 J/g or lower. Catalyst components obtained from the adducts of the present invention are capable to give catalysts for the polymerization of olefins characterized by enhanced activity with respect to the catalysts prepared from the adducts of the prior art.