Ethylene-pentene-hexene copolymer, process for its preparation and use for the production of films

A terpolymer which comprises a polymerization product obtained by polymerizing ethylene, 1-pentene and 1-hexene and which, when it is bottom blown into a film having a thickness of 30 microns on a 31.77 mm extruder with 220° C. melt temperature using a 2:1 blow ratio, complies with the following requisites:

• (a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
• (b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm3;
• (c) an impact strength, as measured according to ASTM D 1709, of greater than 50 g;
• (d) a tensile strength at break, as measured according to ASTM D 882, of greater than 25 MPa in the machine direction (MD) and greater than 25 MPa in the transverse direction (TD);
• and
• (e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by 13C NMR (samples dissolved in 1,2dichlorobenzene).

A terpolymer which comprises a polymerization product obtained by polymerizing ethylene, 1-pentene and 1-hexene and which, when it is bottom blown into a film having a thickness of 30 microns on a 31.77 mm extruder with 220° C. melt temperature using a 2:1 blow ratio, complies with the following requisites:

• (a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
• (b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm3;
• (c) an impact strength, as measured according to ASTM D 1709, of greater than 40 g;
• (d) a tensile strength at yield, as measured according to ASTM D 882, of greater than 15 MPa in the machine direction (MD) and greater than 14 MPa in the transverse direction (TD);
• and
• (e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by 13C NMR (samples dissolved in 1,2dichlorobenzene).

A terpolymer which comprises a polymerization product obtained by polymerizing ethylene, 1-pentene and 1-hexene and which, when it is injection moulded according to ASTM D 647, complies with the following requisites:

• (a) a melt flow index, as measured according to ASTM D 1238, of 0.01 to 100 g/10 minutes;
• (b) a density, as measured according to ASTM D 1505, of 0.890 to 0.950 g/cm3;
• (c) an Izod notched impact strength, as measured according to ASTM D 256, of between 5 and 60 kJ/m2;
• (d) a tensile strength at yield, as measured according to ASTM 638 M, of between 10 MPa and 25 MPa;
• and
• (e) contains units derived from 1-pentene and 1-hexene between 0.1 and 10 molar % as determined by 13C NMR (samples dissolved in 1,2dichlorobenzene).

A process for producing a polymer, which process comprises reacting at least ethylene, 1-pentene and 1-hexene in at least one reaction zone, while maintaining the reaction zone at a pressure between atmospheric pressure and 60 kg/cm2, and at a temperature between 30° C. and 120° C., in the presence of a catalyst system comprising a titanium-based Ziegler-Natta catalyst obtained by

• (i) adding dibutyl ether under inert conditions to a suspension of anhydrous magnesium chloride in an inert saturated hydrocarbon liquid, with the molar ratio of anhydrous magnesium chloride to dibutyl ether being between 0.3:1 and 3:1, and stirring the resultant mixture for a period of 30 minutes to 10 hours at room temperature;
• (ii) adding triethylaluminium dropwise to the suspension, with the molar ratio of triethylaluminium to anhydrous magnesium chloride being between 1:1 and 6:1, to form an activated support-containing slurry;
• (iii) adding to the activated support-containing slurry a three component alcohol mixture consisting of ethanol, hexanol and pentanol, with the molar ratio of the alcohol mixture to the initial magnesium chloride being between 0.4:1 and 4:1;
• (iv) stirring the alcohol/activated support mixture for between 1 and 10 hours;
• and
• (v) adding titanium chloride to the alcohol/activated support mixture such that the molar ratio of titanium chloride to magnesium chloride initially used is between 2:1 and 20:1, to form a magnesium chloride supported titanium catalyst, and, as a cocatalyst, an aluminium compound, thereby to produce a polymerized product.

A polymer composition, which comprises

• (i) a terpolymer of ethylene, 1-pentene and 1-hexene;
• (ii) a phenolic stabilizer component comprising a phenolic oxidant having molecular mass greater than 300, and selected from the group consisting of tetrakis methylene (3,5-di-t-butyl-4-hydroxy hydrocinnamate) methane;
• octadecyl-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl) propionate, 1,3,5-Tris(3′-5′-di-t-butyl-4′hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, and 2,2′Thiodiethyl bis-(3,5-di-t-butyl-4-hydroxyphenyl)-propionate;
• and a monomeric phenolic stabilizer selected from the group consisting of 2,6-bis(1,1-dimethylethyl)-4-(1-methylethenyl)phenol, 2,6-bis(1,1-dimethylethyl)-4-(4-pentenyl)phenol, 2,6-bis(1,1-dimethylethyl)-4-(3,3-dimethyl-1-butenyl)phenol, and 2,6-bis(1,1-dimethylethyl)-4-(2-propenyl)phenol;
• (iii) optionally, at least one organic phosphite stabilizer;
• and
• (iv) a metal salt of a higher aliphatic acid.