CATALYST COMPOSITION FOR THE POLYMERIZATION OF OLEFINS

Abstract

The invention relates to a catalyst composition for the polymerization of olefins, in which the catalyst is produced using a metal-containing compound having the formula (I): MeR.sub.nX.sub.3-n (I), in which X is a halogen, Me is a metal of group III of Mendelejev's Periodic Table of Elements, R is a hydrocarbon moiety comprising>2 carbon atoms, and n is 1≦n<3, or a dimer of a compound of formula (I); and the average particle size of the catalyst as reflected by D.sub.50 (measured according to ISO13320) is between 0.5 and 4.5 μηη. The invention also relates to a process for production of said catalyst composition. The invention further relates to ultra-high molecular weight polyethylene produced via a polymerization process using said catalyst composition.

Claims

1. Catalyst composition for the polymerization of olefins, characterized in that: a) the catalyst is produced using a metal-containing compound having the formula (I):
MeR.sub.nX.sub.3-n  (I) in which X is a halogen, Me is a metal of group III of Mendelejev's Periodic Table of Elements, R is a hydrocarbon moiety comprising>2 carbon atoms, and n is 1≦n<3, or a dimer of a compound of formula (I); and b) the average particle size of the catalyst as reflected by D.sub.50 (measured according to ISO13320) is between 0.5 and 4.5 μm; wherein the catalyst composition comprises the product obtained by combining: a) a hydrocarbon solution comprising: a magnesium-containing compound selected from an organic oxygen-containing magnesium compound and a halogen-containing magnesium compound; and an organic oxygen-containing titanium compound; b) a solution comprising a mixture of: a metal-containing compound having the formula (I):
MeR.sub.nX.sub.3-n  (I) in which X is a halogen, Me is a metal of group III of Mendelejev's Periodic Table of Elements, R is a hydrocarbon moiety comprising>2 carbon atoms, and n is 1≦n<3, or a dimer of a compound of formula (I); and a silicon-containing compound of formula R′.sub.mSiCl.sub.4-m in which 0≦m≦2 and R′ is a hydrocarbon moiety comprising at least one carbon atom; in which the combination of solutions a) and b) results in a suspension of solid particles.

2. Catalyst composition according to claim 1 wherein the metal-containing compound is selected from diisobutyl aluminium chloride, di-n-butyl aluminium chloride, sesquiisobutyl aluminium chloride, or mixtures thereof

3. Catalyst composition according to claim 1 in which the magnesium-containing compound is selected from organic oxygen-containing magnesium compounds such as alkoxides and alkyloxides which may be selected from magnesium methylate, magnesium ethylate, magnesium isopropylate, or magnesium ethylethylate halogen-containing magnesium compounds such as magnesium dihalides

4. Catalyst composition according to claim 1 in which R is a hydrocarbon moiety comprising≧4 carbon atoms the metal Me is selected from aluminium, gallium or boron the halogen X is chlorine, bromine or iodine.

5. Catalyst composition according to claim 1 wherein: the molar ratio of the metal in the metal-containing compound according to formula (I) to the organic oxygen-containing titanium compound is between 0.01 and 0.5; and/or the molar ratio of the hydrocarbon moiety R in the metal-containing compound (I) to the titanium in the oxygen-containing titanium compound is between 0.10 and 0.60; and/or the molar ratio of the metal in the metal-containing compound having the formula (I) to the organic oxygen-containing titanium compound is lower than the molar ratio of the hydrocarbon moiety R in the metal-containing compound (I) to the titanium in the oxygen-containing titanium compound.

6. Process for production of a catalyst composition for polymerization of olefins according to claim 1, characterized in that the process comprises combining: a) a hydrocarbon solution comprising: a magnesium-containing compound selected from an organic oxygen-containing magnesium compound and a halogen-containing magnesium compound; and an organic oxygen-containing titanium compound; b) a solution comprising a mixture of: a metal-containing compound having the formula (I):
MeR.sub.nX.sub.3-n  (I) in which X is a halogen, Me is a metal of group III of Mendelejev's Periodic Table of Elements, R is a hydrocarbon moiety comprising>2 carbon atoms, and n is 1≦n<3, or a dimer of a compound of formula (I); and a silicon-containing compound of formula R′.sub.mSiCl.sub.4-m in which 0≦m≦2 and R′ is a hydrocarbon moiety comprising at least one carbon atom; in which the combination of solutions a) and b) results in a suspension of solid particles.

7. Process according to claim 6 in which the magnesium-containing compound is selected from: organic oxygen-containing magnesium compounds such as alkoxides and alkyloxides which may be selected from magnesium methylate, magnesium ethylate, magnesium isopropylate, or magnesium ethylethylate; halogen-containing magnesium compounds such as magnesium dihalides.

8. Process according to claim 6 in which R is a hydrocarbon moiety comprising≧4 carbon atoms the metal Me is selected from aluminium, gallium or boron the halogen X is chlorine, bromine or iodine.

9. Process according to claim 6 in which the metal-containing compound is selected from n-butyl aluminium dichloride, isobutyl aluminium dichloride, diisobutyl aluminium chloride, di-n-butyl aluminium chloride, sesquiisobutyl aluminium chloride, or mixtures thereof

10. Polymerization process for production of a polyolefin material using a catalyst composition according to claim 1, in which the polyolefin material is selected from linear low-density polyethylene, medium density polyethylene, high-density polyethylene, or ultra-high molecular weight polyethylene.

11. Ultra-high molecular weight polyethylene powder produced via a polymerization process using a catalyst composition according to claim 1, characterized in that the yield as defined by the weight of polymer produced per weight unit of catalyst used in the process is greater than 15 kg polymer/g catalyst and in that the average particle size D.sub.50 of the ultra-high molecular weight powder particles is lower than 175 μm.

12. Use of an ultra-high molecular weight polyethylene powder according to claim 11 for production of moulded articles.

13. Rods, tubes, bars, profiles, sheets or fibers prepared using an ultra-high molecular weight polyethylene powder according to claim 11.

14. Polymerization process for production of a polyolefin material using a catalyst composition obtained via the process according to claim 6, in which the polyolefin material is selected from linear low-density polyethylene, medium density polyethylene, high-density polyethylene, or ultra-high molecular weight polyethylene.

15. Ultra-high molecular weight polyethylene powder produced via a polymerization process using a catalyst composition obtained via a process according to claim 6, characterized in that the yield as defined by the weight of polymer produced per weight unit of catalyst used in the process is greater than 15 kg polymer/g catalyst and in that the average particle size D.sub.50 of the ultra-high molecular weight powder particles is lower than 175 μm.

Description

EXAMPLES

[0097] The invention will now be illustrated by the following non-limiting examples.

Experiment I: Preparation of Hydrocarbon Solution of Magnesium-Containing Compound and Organic Oxygen-Containing Titanium Compound

[0098] To a 1 I round bottom flask equipped with a stirrer, a dropping funnel and a water cooler, 25 g of Mg(OC.sub.2H.sub.5).sub.2 (0.218 mol) as a solid and 37 ml of Ti(OC.sub.4H.sub.9).sub.4 (0.107 mol) as a liquid were added, both at room temperature (20° C.). The dropping funnel was filled with 370 ml of hexane. The mixture of Mg(OC.sub.2H.sub.5).sub.2 and Ti(OC.sub.4H.sub.9).sub.4 in the round-bottom flask was heated to a temperature of 180° C. and stirred at 300 rpm for 1.5 hours. A clear liquid was obtained. The mixture was then cooled down to 120° C. The hexane was added slowly whilst the solution was kept at a temperature of 120° C. After the hexane was added to the solution completely, the solution was cooled down to room temperature. The resulting solution was stored under nitrogen. Analyses on the solution showed a titanium concentration of 0.25 mol/I.

Experiment IIA: Catalyst Preparation

[0099] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 1.17 ml of diisobutylaluminium chloride (6 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h, during which the reactor was kept at room temperature (20° C.). The resulting suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 4.0 μm. The molar ratio of isobutyl-moieties to titanium atoms in the obtained catalyst was 0.24. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.12.

Experiment IIB: Catalyst Preparation

[0100] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 2.34 ml of diisobutylaluminium chloride (12 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The resulting suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 3.4 μm. The molar ratio of isobutyl-moieties to titanium atoms in the obtained catalyst was 0.48. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.24.

Experiment IIC: Catalyst Preparation

[0101] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 0.585 ml of diisobutylaluminium chloride (3 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 4.5 μm. The molar ratio of isobutyl-moieties to titanium atoms in the obtained catalyst was 0.12. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.06.

Experiment IID: Catalyst Preparation (Comparative)

[0102] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 3.5 ml of a 50% ethyl aluminium dichloride (12 mmol Al) solution in hexane was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 4.9 μm. The molar ratio of ethyl-moieties to titanium atoms in the obtained catalyst was 0.24. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.24.

Experiment IIE: Catalyst Preparation (Comparative)

[0103] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 0.75 ml of diethyl aluminium chloride (6 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 7.4 μm. The molar ratio of ethyl-moieties to titanium atoms in the obtained catalyst was 0.24. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.12.

Experiment IIF: Catalyst Preparation (Comparative)

[0104] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 1.5 ml of diethyl aluminium chloride (12 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 7.2 μm. The molar ratio of ethyl-moieties to titanium atoms in the obtained catalyst was 0.48. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.24.

Experiment IIG: Catalyst Preparation (Comparative)

[0105] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 1.5 ml of 50% ethyl aluminium dichloride solution in hexane (5.1 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 5.1 μm. The molar ratio of ethyl-moieties to titanium atoms in the obtained catalyst was 0.12. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.12.

Experiment IIH: Catalyst Preparation (Comparative)

[0106] In a 1 I baffled reactor equipped with a stirrer and a condenser, 400 ml of hexane was introduced. To this, 4.68 ml of diisobutylaluminium chloride (24 mmol Al) was added, followed by 17.3 ml of tetrachlorosilane. The stirrer was started at 1700 rpm. Via a peristaltic pump, 200 ml of the solution of Experiment I was added gradually over a period of 4 h during which the reactor was kept at room temperature (20° C.). The suspension was subsequently refluxed for 2 h at the boiling temperature of hexane (69° C.), after which it was cooled down to room temperature, filtered and washed with 2 I of hexane. The obtained catalyst was mixed with hexane, and stored under nitrogen. The average particle size D.sub.50 of the catalyst particles thus obtained was determined to be 5.5 μm. The molar ratio of isobutyl-moieties to titanium atoms in the obtained catalyst was 0.96. The molar ratio of aluminium atoms to titanium atoms in the obtained catalyst was 0.48.

Experiment IIIA: Polymerization

[0107] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIA containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0108] The yield of polymer was 23.4 kg/g of catalyst, whereas the catalyst activity was 3 kg polyethylene per g catalyst per hour per bar.

[0109] The resulting UHMPWE product had an average particle size D.sub.50 of 101 μm, and an elongational stress of 0.409 N/mm.sup.2.

Experiment IIIB: Polymerization

[0110] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIB containing 20 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0111] The yield of polymer was 46.0 kg/g of catalyst, whereas the catalyst activity was 5.6 kg polyethylene per g catalyst per hour per bar.

[0112] The resulting UHMPWE product had an average particle size D.sub.50 of 101 μm, and an elongational stress of 0.378 N/mm.sup.2.

Experiment IIIC: Polymerization

[0113] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIC containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0114] The yield of polymer was 16.2 kg/g of catalyst, whereas the catalyst activity was 1.6 kg polyethylene per g catalyst per hour per bar.

[0115] The resulting UHMPWE product had an average particle size D.sub.50 of 111 μm, and an elongational stress of 0.423 N/mm.sup.2.

Experiment IIID: Polymerization (Comparative)

[0116] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IID containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0117] The yield of polymer was 11,0 kg/g of catalyst, whereas the catalyst activity was 2.0 kg polyethylene per g catalyst per hour per bar.

[0118] The resulting UHMPWE product had an average particle size D.sub.50 of 117 μm, and an elongational stress of 0.420 N/mm.sup.2.

Experiment IIIE: Polymerization (Comparative)

[0119] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIE containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0120] The yield of polymer was 2.9 kg/g of catalyst, whereas the catalyst activity was 0.36 kg polyethylene per g catalyst per hour per bar.

Experiment IIIF: Polymerization (Comparative)

[0121] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIF containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0122] The yield of polymer was 4.33 kg/g of catalyst, whereas the catalyst activity was 0.54 kg polyethylene per g catalyst per hour per bar.

[0123] The resulting UHMPWE product had an average particle size D.sub.50 of 138 μm, and an elongational stress of 0.438 N/mm.sup.2.

Experiment IIIG: Polymerization (Comparative)

[0124] The polymerization reaction was carried out in a 10 I autoclave using 5 I purified hexane as diluent. 7.5 mmol of triisobutyl aluminium was added to the hexane. The mixture was heated to 75° C. and pressurized with ethylene at a pressure of 4.5 barg. Subsequently a quantity of catalyst slurry obtained from Experiment IIG containing 40 mg of catalyst was dosed. The temperature was maintained at 75° C. and the pressure was kept constant by feeding ethylene. The reaction was stopped when approximately 1000 g of ethylene had been supplied to the reactor or when the reaction had lasted for 2 hours. Stopping was performed by de-pressurizing and cooling down the reactor. The reactor contents were passed through a filter. The polymer powder was collected, dried and analyzed.

[0125] The yield of polymer was 3.3 kg/g of catalyst, whereas the catalyst activity was 0.42 kg polyethylene per g catalyst per hour per bar.

[0126] The resulting UHMPWE product had an average particle size D.sub.50 of 140 μm.

[0127] From the examples above, it becomes evident that catalyst compositions according to the present invention, in which the catalyst is produced using a metal-containing compound having the formula MeR.sub.nX.sub.3-n in which R is a hydrocarbon moiety comprising>2 carbon atoms and having an average particle size of the catalyst as reflected by D.sub.50 between 0.5 and 4.5 μm, result in a clear improvement of catalyst activity and yield during polymerisation of ethylene to UHMWPE, whilst resulting in a polymer product having desired small particle size. For example, catalyst compositions according to the present invention in which the catalyst is produced using a metal-containing compounds having the formula MeR.sub.nX.sub.3-n in which R is an isobutyl moiety and in which n=2 result in an improvement of the catalyst activity and