Heterogeneous ziegler-natta catalyst system and a process for olefin polymerization using the same

A process for the preparation of a heterogeneous Ziegler-Natta catalyst system for preparation of UHMWPE;

• said process comprising the following steps:
• titanating at least one magnesium compound with at least one titanium halide, followed by allowing said titanium halide to bond with said magnesium compound, to obtain a mixture comprising at least one procatalyst;
• wherein the molar ratio of elemental magnesium to elemental titanium to halide is 1:1.3:3.7;
• separating and washing said mixture comprising the procatalyst to obtain a procatalyst;
• admixing said procatalyst and at least one organo-aluminum compound as a co-catalyst, in the presence of at least one hydrocarbon medium, to obtain an activated catalyst, wherein the molar ratio of elemental aluminum, present in said organo-aluminum compound to elemental titanium, present in said procatalyst, ranges between 6:1 and 12:1;
• and
• adding, in a controlled manner, at least one organo-silane compound of Formula 1 as an external donor to said activated catalyst, in the presence of at least one hydrocarbon medium, under inert conditions, at a temperature ranging between 25° C. and 30° C. and over a time period ranging between 2 and 10 minutes, to obtain a heterogeneous Ziegler-Natta catalyst system, wherein the molar ratio of elemental silicon, present in said organo-silane compound to elemental titanium, present in said procatalyst is 4:1,
• wherein R1, R2, R3 and R4 of said organo-silane compound is at least one selected from the group consisting of C1-C14 branched or straight chain alkyl, C1-C14 branched or straight chain alkyl oxy, substituted or unsubstituted aryl, substituted or unsubstituted aryl oxy, C4-C14 cyclic alkyl and C4-C14 cyclic alkyl oxy.

A process for the preparation of UHMWPE;

• said process comprising the following steps:
• titanating at least one magnesium compound with at least one titanium halide, followed by allowing said titanium halide to bond with said magnesium compound, to obtain a mixture comprising at least one procatalyst;
• wherein the molar ratio of elemental magnesium to elemental titanium to halide is 1:1.3:3.7;
• separating and washing said mixture comprising the procatalyst to obtain a procatalyst;
• admixing said procatalyst and at least one organo-aluminum compound as a co-catalyst, in the presence of at least one hydrocarbon medium, to obtain an activated catalyst, wherein the molar ratio of elemental aluminum, present in said organo-aluminum compound to elemental titanium, present in said procatalyst, ranges between 6:1 and 12:1;
• and
• adding, in a controlled manner, at least one organo-silane compound of Formula 1 as an external donor to said activated catalyst, in the presence of at least one hydrocarbon medium, under inert conditions, at a temperature ranging between 25° C. and 30° C. and over a time period ranging between 2 and 10 minutes, to obtain a heterogeneous Ziegler-Natta catalyst system, wherein the molar ratio of elemental silicon, present in said organo-silane compound to elemental titanium, present in said procatalyst is 4:1, and
• incorporating said heterogeneous Ziegler-Natta catalyst system in ethylene monomer at a temperature ranging between 30° C. and 125° C., under ethylene pressure ranging between 2 bar and 10 bars, followed by agitation at a speed ranging between 300 and 700 revolutions per minute to obtain a polyolefin, wherein the ratio of said catalyst system and said monomer ranges between 1:20 and 1:220,
• wherein R1, R2, R3 and R4 of said organo-silane compound is at least one selected from the group consisting of C1-C14 branched or straight chain alkyl, C1-C14 branched or straight chain alkyl oxy, substituted or unsubstituted aryl, substituted or unsubstituted aryl oxy, C4-C14 cyclic alkyl and C4-C14 cyclic alkyl oxy,
• said UHMWPE being characterized by molecular weight ranging between 3 and 17 million g/mole, bulk density ranging between 0.3 and 0.4 g/cc, intrinsic viscosity ranging between 20 and 65 dl/g, average particle size ranging between 155 and 165 microns and molecular weight distribution ranging between 10 and 14.