Abstract: Copolymers comprising ethylene and alpha-olefins having (a) a density (D) in the range 930-960/g/m3 (b) a melt index (MI2) in the range 0.1-3.5 g/10 min (c) a melt elastic modulus G? (G?=500 Pa) in the range 40 to 150 Pa, and (d) a ratio of complex dynamic shear viscosities ?*(0.1)/?(100) in the range 1.5 to 5.5. The copolymers are suitable for use as Polyethylenes of Raised Temperature Resistance (PE-RT) for use in hot water piping systems. The copolymers may be prepared by use of meltallocene catalyst systems. Pipes having a time to failure of ?500 hrs measured according to ISO 1167 at 110° C. and 2.6 MPa prepared in a single reactor are also disclosed.

Abstract: Polymerization process in a loop reactor of an olefin monomer optionally together with an olefin commoner in the presence of a polymerization catalyst in a diluent to produce a slurry containing solid particulate olefin polymer and the diluent. The Froude number is maintained in the range of 2-15.

Abstract: Propylene random copolymer composition containing (A) 60-80 wt % of a copolymer of propylene and from 0.1 to 2 wt % of units derived from ethylene; and (B) 20-40 wt % of a copolymer of propylene and from 7 to 15 wt % of units derived from ethylene. The composition has a total ethylene content of from 3 to 4.5 wt % and a melt flow rate value according to ISO 1133 (230° C., 2.16 kg) of from 10 to 120 g/100 min. Cast films, sheets, or injection molded or injection stretch blow molded articles made from the above composition are also disclosed.

Abstract: Process including polymerizing in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent. The Froude number is maintained at or below 20.

Abstract: Process for polymerizing in a loop reactor an olefin monomer optionally together with an olefin comonomer in the presence of a polymerization catalyst in a diluent to produce a slurry including solid particulate olefin polymer and the diluent. The Froude number is in the range 3 to 10, the internal diameter of the loop reactor is over 600 millimeters, the solids concentration of the slurry in the loop reactor is above 20% by volume and, when the polymer produced is polyethylene and the diluent is an alkane, the solids concentration is above 40 wt % based on the total weight of the slurry.

Abstract: Fibers, tapes, monofilaments including copolymers of ethylene and ?-olefins which exhibit improved tensile properties expressed as a balance between tenacity and elongation at break. The copolymers may be prepared by use of metallocene catalyst systems in particular by use of monocyclopenadienyl catalyst systems. The fibers, tapes, monofilaments of the invention are particularly suitable for end-use applications including artificial grass, woven and nonwoven fabrics, cordages, ropes, netting and flexible intermediate bulk containers.

Abstract: Copolymers of ethylene and ?-olefins having (a) a density (D) in the range 0.900-0.940 g/cm3, (b) a melt index MI2 (2.16 kg, 190° C.) in the range of 0.01-50 g/10 min, (c) a melt index MI2 (2.16 kg, 190° C.) and Dow Rheology Index (DRI) satisfying the equation [DRI/MI2]>2.65, and (d) a Dart Drop Impact (DDI) in g of a blown film having a thickness of 25 ?m produced from the copolymer satisfying the equation DDI?1900×{1?Exp [?750(D?0.908)2]}×{Exp [(0.919?D)/0.0045]}. The copolymers may be prepared using metallocene catalysis and are preferably prepared in multistage processes carried out in loop reactors in the slurry phase. The copolymers exhibit long chain branching as defined by Dow Rheology Index (DRI) and exhibit unexpected improvements in mechanical properties, in particular dart drop impact, when extruded into blown films.

Abstract: A process comprising polymerising in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerisation catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed.

Abstract: A composition suitable for use in pressure pipes and pipe fittings is disclosed comprising polymer of ethylene and from 0.5 to 5 wt % of a C4-C8 alpha-olefin which has a natural density of 935-956 kg/m3, a melt index MI5 of 0.15-0.5 g/10 min, a dynamic complex viscosity at 100 rad/s and 190° C. (?100) of no more than 2500 Pa·s, a relationship between ?100 and dynamic complex viscosity measured in Pa·s at 0.01 rad/s and 190° C. (?0.01) defined by the equation ?0.01>115000+30. ?100, and an environmental stress crack resistance as measured by a notched pipe test performed according to ISO13479:1997 on 110 mm SDR 11 pipes at 80° C. and a pressure of 9.2 bar, of greater than 1000 hours, or: wherein the C4-C8 alpha-olefin is 1-hexene or 1-octene.

Abstract: A propylene random copolymer composition is disclosed, comprising (A) 60-80 wt % of a copolymer of propylene and from 0.1 to 2 wt % of units derived from ethylene; and (B) 20-40 wt % of a copolymer of propylene and from 7 to 15 wt % of units derived from ethylene, said composition having a total ethylene content of from 3 to 4.5 wt % and a melt flow rate value according to ISO 1133 (230° C., 2.16 kg) of from 10 to 120 g/100 min. Cast films, sheets, or injection moulded or injection stretch blow moulded articles made from the above composition are also disclosed.

Abstract: An insulated cable is disclosed which comprises an electrical core conductor (1) having arranged coaxially around it at least three extruded layers of polymer-based material, which layers comprise an insulating layer (3) comprising a copolymer of polyethylene and an acrylate, an outer layer (5) of a semi-conductive material, and an intermediate layer (4) between the insulating and outer layers which comprises polyethylene and is substantially free of any acrylate or conducting material, such that the outer layer (5) is strippable from the intermediate layer (4).

Abstract: A process comprising polymerizing in a loop reactor an olefin monomer optionally together with an olefin commoner in the presence of a polymerization catalyst in a diluent to produce a slurry comprising solid particulate olefin polymer and the diluent wherein the Froude number is maintained at or below 20 is disclosed.

Abstract: Process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, by passing the stream through at least two heaters operating in parallel, each heater having at least one transfer line for the stream and a heater for heating the transfer line. The average particle of the polymer is below 3 mm, the temperature of the polymer-containing stream at the outlet of all heaters is maintained above the dew point of the stream, and no heater has a volumetric flowrate of polymer-containing stream more than three times that of any other heater.

Abstract: A pressure pipe resin is disclosed comprising from 90 to 99.9 wt %, based on the total weight of the resin, of a polyethylene, and from 0.1 to 10 wt %, based on the total weight of the blend, of an ionomer.

Abstract: Process for making a film or pipe by compounding an uncompounded polyolefin powder having a particle size distribution such that D95 is less than 355 ?m and (D90?D10)/D50 is less than 1.2, where D95, D90, D50 and D10 are defined such that 95 wt %, 90 wt %, 50 wt % or 10 wtl % of the polymer particles have a diameter of less than D95, D90, D50 and D10 respectively, to form pellets; and then forming the pellets into a film or pipe.

Abstract: Process for heating a polymer-containing stream being transferred from a polymerization reactor to a separation zone or device, by passing the stream through a heater having at least one transfer line for the stream and a heater for heating the transfer line. The average particle size of the solid polymer is less than 3mm, the mass flowrate of the polymer-containing stream exiting the heater is no more than 15% greater than the mass flowrate exiting the reactor, the average velocity of the polymer-containing stream either at a point 80% along the length of the heated part of the transfer line measured from the transfer line inlet, or at the transfer line outlet, is at least 6 m/s, and the pressure drop across the transfer line per unit length is between 0.0125 bar/m and 0.1 bar/m.

Abstract: Process for polymerising, in a loop reactor, at least one olefin monomer in a liquid diluent to produce a slurry comprising solid particulate olefin polymer and said diluent, wherein the ratio between the actual volumetric solids concentration of the slurry and the maximum possible geometric volume solids concentration of the slurry as measured by the bulk density of an unpacked settled bed of particles, SVCR, is V*0.065 or greater, and the ratio of the cumulative settling distance of an average size particle at any point in the reactor in any direction perpendicular to the direction of the flow, to the internal diameter of the loop reactor, is maintained below [0.084*(V?6.62)+(0.69?SVCR)* 1.666], where V is the circulation velocity of the slurry in m/s and “cumulative settling distance” is defined as the cumulative distance, expressed as a fraction of the diameter, travelled by a particle in any direction perpendicular to the direction of the flow since the previous upstream pump.

Abstract: Process for removing heat from at least two reactors forming at least part of a polymerization reactor system for a multimodal polymerization in which the reactors are linked in series and all produce at least one component of the same polymer. The process includes cooling a stream of fluid in one or more heat exchangers and passing part of it to the cooling system of a first reactor and part of it to the cooling system of a second reactor, so as to remove the heat from said reactors, and passing back through the heat exchangers a return flow having a portion of the combined exit flows of the cooling fluids used to remove the heat from each of the reactors. The heat exchangers provide at least 90% of the cooling requirement for the reactors, and a portion of the combined exit flows from the reactors bypasses at least one of the heat exchangers and is passed directly to the cooling system of one or more of the reactors. The cooling circuit is powered by no more than one pump at any one time.

Abstract: Process for producing a multimodal polyethylene in at least two reactors connected in series, in which 20-80 wt % of a first polymer is made in suspension in a first reactor and 80-20 wt % of a second polymer is made in suspension in a second reactor in the presence of the first polymer, and a stream or slurry containing the resulting polymer is withdrawn from the second reactor and transferred to a flash tank operating at a pressure and temperature such that at least 50 mol % of the liquid component of the slurry, or the non-polymer component of the stream entering the flash tank, is withdrawn from the flash tank as a vapour, wherein the concentration in the stream or slurry entering the flash tank of components having a molecular weight below 50 g/mol, Clights (mol %), satisfies the equation Clights<7+0.07(40?Tc)+4.4(Pc?0.8)?7(CH2/CEt) where Tc and Pc are respectively the temperature (in ° C.

Abstract: Process for providing a flow of particulate matter to a reactor, by intermittently adding the particulate matter and a diluent to a mixing tank, and continuously withdrawing a slurry of particulate matter in diluent from the mixing tank for introduction into the reactor. Prior to each addition of particulate matter and diluent to the mixing tank, the concentration of particulate matter in the diluent already in the mixing tank is measured or calculated, and the amount of particulate matter and diluent subsequently added is measured so as to achieve the same concentration at the end of the addition as that measured or calculated prior to the addition.