Abstract:
Propylene-ethylene copolymers are flexible and show a very good balance between softness and mechanical properties in their crude state are obtained by solution polymerization in the presence of Ziegler-Natta catalysts. The said copolymers comprise from 10 to 50%wt of ethylene and are characterized by: product of the comonomer reactivity ratio r1 r2 =1.5; absence of 2,1 propylene insertions and tensile strength at break higher than 4 Mpa.
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:
A solution process for polymerizingone or more α-olefins of formula CH2=CHR, where R is H or an alkyl radical C1-12,to produce a polyolefin soluble in the reaction medium, the process comprising: a) polymerizing said one or more α-olefins in a solution phase in the presence of a polymerization catalyst and a inert solvent having a vapor pressure lower than 100 kPa at 20°C; b) separating the produced polyolefin from the unreacted monomers and the inert solvent by means of a sequence of at least three volatilization chambers operating at a decreasing pressure, the second devolatilization chamber being operated at a pressure from 0.8 to 5 bar.
Abstract:
Propylene-ethylene copolymers are flexible and show a very good balance between softness and mechanical properties in their crude state are obtained by solution polymerization in the presence of Ziegler-Natta catalysts. The said copolymers comprise from 10 to 50%wt of ethylene and are characterized by: product of the comonomer reactivity ratio r1•r2 ≤1.5; absence of 2,1 propylene insertions and tensile strength at break higher than 4 Mpa.
Abstract:
A process is provided for the preparation of a solid catalyst component for the polymerisation of olefins, comprising continuously feeding a liquid containing a titanium compound having at least one titanium-halogen bond into a vessel containing a solid comprising a magnesium halide and continuously discharging liquid from the vessel, whereby the concentration of the solid is maintained within the range of between 80 and 300 g/l, and the product between the average residence time of the liquid in the vessel and the concentration of the solid is maintained below 10,000 min*g/l. An advantage of the process is the reduced time and reactor volume necessary to prepare the catalysts, which show good activity and stereospecificity.