Abstract:
A polyolefin composition, particularly fit for the production of extrusion blow molded articles, comprising (a) a propylene-ethylene copolymer having a content of units deriving from ethylene of 4.0 % by weight or higher, and (b) a nucleating agent and having a crystallization temperature (Tc) higher than 117°C can be obtained by copolymerizing propylene and ethylene in the presence of a catalyst system obtained by contacting a 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 present in an amount from 40 to 90% by mol with respect to the total amount of donors and selected from succinates and the other selected from 1,3 diethers, an aluminum hydrocarbyl compound, and optionally an external electron donor compound.
Abstract:
A process and apparatus for producing olefin polymers are disclosed, comprising: a. polymerizing one or more olefins in the gas phase, in the presence of an olefin polymerization catalyst, whereby growing polymer particles flow along a cylindrically- shaped downward path in densified form under the action of gravity so as to form a densified bed of downward-flowing polymer particles b. allowing said polymer particles to flow through a restriction of the densified bed, such restriction being positioned in a restriction zone extending from the bed upward to a distance of 15% of the total height of the densified bed; and c. metering an antistatic agent through a feed line connected to the densified bed at a feed point being located in a feed zone extending from the top of the restriction upward, to a distance five times the diameter of the section of the densified bed above the restriction.
Abstract:
Solid adducts comprising MgCl 2 , ethanol and water characterized in that the amount of ethanol ranges from 50% to less than 57% by weight, the amount of water is ranges from 0.5 to 5% by weight, the ethanol/water weight ratio is lower than 60 and the porosity determined with Hg method due to pores with radius up to 1μm and expressed in cm 3 /g, is lower than 0.2.
Abstract:
Catalyst component for the polymerization of olefins comprising Mg, Ti and an electron donor compound of the following formula (I) in which R1 groups are selected from C 1 -C 15 hydrocarbon groups, R 8 groups, equal or different to each other, are selected from hydrogen, halogen and C 1 -C 15 hydrocarbon groups, optionally containing an heteroatom selected from halogen, O, P, S, N and Si and L is a divalent hydrocarbon group optionally containing heteroatoms selected from halogen, O, P, S, N and Si.
Abstract:
A pre-polymerized catalyst component for the polymerization of olefins endowed with high activity and morphological stability comprises (i) a non-stereospecific solid catalyst component comprising Ti, Mg and a halogen and having a porosity, due to pores with radius up to 1 μm, ranging from 0.2 to 0.8 cm 3 /g and (ii) an amount of an ethylene/alpha-olefm block (co)polymer ranging from 0.1 up to 5g per g of said solid catalyst component (i), said pre-polymerized catalyst component being characterized by a mercury porosity due to pores up to 1 μm of less than 70% the mercury porosity value of the said non-stereospecific solid catalyst component (i).
Abstract:
A processfor the preparation of propylene polymer compositions comprising from 50 to 90 % by weight of a propylene (co)polymer fraction insoluble in xylene at 25°C, and from 10 to 50% by weight of an ethylene copolymer fraction soluble in xylene at 25°C, said process comprising: (i)a first step of polymerizing propylene in the optional presence of ethylene and/or C 4 - C 10 alpha olefins, to produce a propylene (co)polymer being for at least 85% by weight insoluble in xylene at 25°C; and (ii)a successive step, carried out in gas-phase, in the presence of the product coming from step (i), of copolymerizing a mixture of ethylene with one or more α-olefins CH 2 =CHR in which R is a hydrocarbon radical having 1-10 carbon atoms, to produce an ethylene copolymer; the process being carried out in the presence of a catalyst system comprising: the product obtained by contacting: (a) a solid catalyst component comprising a magnesium halide, a titanium compound having at least a Ti-halogen bond and at least two internal electron donor compounds one of which being present in an amount from 35 to 90% by mol with respect to the total amount of donors and being selected from succinates and the other being selected from 1,3-diethers, the total amount of internal electron donor compounds being lower than 14.0% by weight with respect to the total weight of the solid catalyst component; with (b) an aluminum hydrocarbyl compound, and optionally with (c) an external electron donor compound.
Abstract:
A polyolefm compositions comprising: A) From 77 wt% to 90 wt%, of a propylene homopolymer having the fraction soluble in xylene at 25 °C lower than 2 wt%; B) from 10 wt% to 23 wt% of a copolymer of ethylene with one C4-C10 alpha-olefin containing from 20 wt% to 30 wt%, of said C4-C10 alpha-olefin derived units; said composition having - the value of melt flow rate (MFR) at 230 °C, 2.16 kg of from 0.5 to 4.5 g/10 min; - the total content of ethylene of from 10 wt% to 18 wt%; - the value of the intrinsic viscosity of the total fraction soluble in Xylene at 25°C (AMXSIVtot) is less than 1.5 dl/g.
Abstract:
A terpolymer containing propylene, ethylene and an alpha olefins of formula CH2=CHZ wherein Z is an hydrocarbon group having from 2 to 10 carbon atoms wherein: (i) the content of ethylene derived units ranges from 0.5 wt% to 5.0 wt%; (ii) the content of alpha olefin derived units ranges from 1.0 wt% to 5.0 wt%; (iii) the area of the DSC curve after the peak of the melting point (Tm) represents more than 22%; of the total area of the DSC curve; (iv) the polydispersity index (PI) ranges from 2.0 to 7.0.
Abstract:
Solid adducts comprising MgCl 2 and an alcohol ROH in which R is a C1-C20 hydrocarbon group, in which the amount of alcohol ranges from higher than 42% to 60% by weight and the porosity determined with Hg method due to pores up to 1 μm and expressed in cm 3 /g, is such that the value of its ratio with the amount of alcohol in percentage falls above the straight line defined by the equation y=-0.0158x+ 1.03 in which y is the porosity of the adduct and x is the alcohol percentage by weight.