Abstract:
A process for the gas-phase polymerization of α-olefms carried out in two interconnected polymerization zones, wherein the growing polymer particles flow through the first of said polymerization zones (riser) under fast fluidization conditions, leave said riser and enter the second of said polymerization zones (downcomer) through which they flow downward in a densified form, the process being characterized in that: (a) the gas mixture present in the riser is totally or partially prevented from entering the downcomer by introducing into the upper part of said downcomer a liquid stream LB having a composition different from the gaseous mixture present in the riser; (b) the ratio R between the flow rate F p of polymer circulated between said downcomer and said riser and the flow rate LB of said liquid being adjusted in a range from 10 to 50.
Abstract:
A polyolefin composition having good transparency and mechanical properties comprising, all percent amounts being by weight: A) from 70 to 98% of a propylene homopolymer or copolymer having haze of 25% or less and melting temperature of 130°C or higher; and B) from 2 to 30% of a butene-1 copolymer containing from 0.5 to 30% of one or more comonomer(s).
Abstract:
A method for controlling a solution process for the polymerisation of olefins is disclosed. The method is based on an algorithm that calculates predicted operating parameters of the process, including calculation of the extent of reaction (ξ), as a function of the solution density (ρ), and then calculation of the whole composition of the solution. The algorithm resolves a system of equations comprising the equation of state in the PC-SAFT form, the Lewis-Mayo equation for monomer incorporation into a copolymer, and the stoichiometry equation. Predicted parameters are compared to target parameters to detect possible deviations and implement corresponding compensation in the feed.
Abstract:
Thermoset polyolefin elastomer obtained by static curing with water a silane-grafted thermoplastic heterophasic polyolefin composition (I) having a flexural modulus equal to or lower than 150 MPa, and comprising: (a) a crystalline propylene homopolymer or copolymer of propylene with up to 15% by weight of ethylene or other alpha-olefin comonomer(s), or their combinations, and (b) a copolymer or a composition of copolymers of ethylene with other alpha-olefins containing from 15% by weight to less then 40% by weight of ethylene; said thermoset polyolefin elastomer having a compression set value of from 30 to 65%, a ratio of elongation at break to compression set values of above 8, and hardness shore A values below 90.
Abstract:
Polyolefin composition comprising, in percent by weight: A) 50-75% of a blend of polymers (PP) and (EC I ), wherein (PP) is selected from the group consisting of: (i) propylene homopolymers; (ii) copolymers of propylene; (iii) combinations of said homopolymers (i) and copolymers (ii); (EC 1 ) is a copolymer of ethylene and propylene or CH 2 =CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical, or a copolymer of ethylene, propylene and the said CH 2 =CHR alpha-olefin(s), containing from 20 to 35%, of ethylene; and B) 25-50% of a copolymer (EC II ) of ethylene and propylene or CH 2 =CHR alpha-olefin(s), where R is a 2-8 carbon alkyl radical,or a copolymer of ethylene, propylene and the said CH 2 =CHR alpha-olefin(s), containing from 40 to 60% of ethylene; in which composition the copolymer component (EC I ) is present in amounts from 23 to 45% with respect to the total weight of (A),and the intrinsic viscosity [η tot ] of the fraction XS soluble in xylene at room temperature, referred to the total weight of (A) + (B), is of 3.5 dl/g or more.
Abstract:
A process for the polymerization of olefins comprising: a) polymerizing at least a liquid olefin monomer in a polymerization reactor to form a polymerization slurry comprising a polyolefin and said liquid monomer; b) continuously transferring the polymerization slurry from the polymerization reactor to a flash chamber by means of a transfer line comprising a pipe where a turbulent flow of a tri-phase stream comprising polymer, liquid monomers, and gaseous monomers is established; c) separating the evaporated monomer from the polymer in said flash chamber; the process being characterized in that an anti-fouling agent in a liquid form is continuously introduced upstream the inlet of said pipe of step (b).
Abstract:
A propylene polymer composition having a Flexural modulus lower than 500MPa, a total ethylene content from 9 to 30% by weight, a xylene soluble fraction at room temperature higher than 25% by weight, a melting temperature measured by DSC (Tm°C) from 130 to 150°C and a ratio between the weight of xylene soluble fraction at 25°C and the hexane soluble fraction determined on plaque (100μm) of higher than 4.
Abstract:
Polypropylene compositions having a MFR value (2.16 kg, 230 °C) from 15 to 200 g/10 min., comprising: A) a propylene polymer or polymer composition selected from propylene homopolymers or copolymers of propylene containing up to 5% by moles of comonomer(s), said homopolymers and copolymers having values of MFR, obtained without degradation treatments, from 500 to 2500 g/10 min., or combinations of the said homopolymers or copolymers; B) a filler or pigment, or their combinations; and optionally C) from 0.5 to 5% by weight, with respect to the total weight of A), B) and C), of a compatibilizer.
Abstract:
A process for producing a polybutene-1 composition having increased crystallization temperature T c A , comprising the step of blending the following components: A) a butene-1 polymer or polymer composition having crystallization temperature T c A equal to or higher than 50 °C; B) 50 to 3000 ppm by weight, with respect to the total weight of A) and B), of one or more metal complexes of polyhydric alcohols; said butene-1 polymer or polymer composition A) being brought to the molten state or maintained in the molten state during the blending step.
Abstract:
A process for the multistage polymerization of olefins comprising a gas-phase polymerization carried out in at least two serially connected gas-phase reactors, the continuous discharge of polymer and gas reaction mixture from an upstream reactor into a transfer device and the continuous feeding of polymer from said transfer device to a downstream reactor, said transfer device comprising: a) a separation chamber in which said gas reaction mixture is removed from the polymer; b) at least a couple of lock hoppers working intermittently in parallel, where one of said lock hoppers is continuously filled with the polymer coming from step a), while simultaneously the other one is continuously pressurized by means of a gas comprising the reaction mixture coming from said downstream reactor.