Procatalyst composition made with a combination of internal electron donors
A phthalate-free procatalyst composition is disclosed for olefin polymerization that exhibits excellent polymerization activity and response to hydrogen, and can produce a polyolefin exhibiting high stereoregularity, high melt flow rate, and desirable molecular weight distribution. The method for producing the procatalyst composition includes reaction of a magnesium support precursor with a tetravalent titanium halide and a combination of different internal electron donors. The first internal electron donor may comprise one or more substituted phenylene aromatic diester and the second internal electron donor may comprise a polyether, preferably a 1,3-diether. In one embodiment, the support precursor comprises a spherical spray crystalized MgCl 2 -EtOH adduct.
1. A procatalyst composition for stereoselective polymerization of propylene comprising:
a combination of a magnesium moiety, a titanium moiety, and a mixed internal electron donor, the mixed internal electron donor comprising at least a first internal electron donor and a second internal electron donor, the first internal electron donor comprising a non-phthalate substituted phenylene aromatic diester internal electron donor, the second internal electron donor comprising a 1,3-diether.
2. A procatalyst composition as defined in claim 1 , wherein the first internal electron donor and the second internal electron donor are present in the composition in a molar ratio of from about 10:1 to about 1:10.
3. A procatalyst composition as defined in claim 1 , wherein the second internal electron donor has the following structure:
where R 1 , R 2 , R 3 , and R 4 are the same or different and comprise methyl, C 2 -C 18 linear or branched alkyls, C 3 -C 18 cycloalkyls, C 4 -C 18 cycloalkyl-alkyls, C 4 -C 18 alkyl-cycloalkyls, phenyls, organosilicons, C 7 -C 18 arylalkyls, C 7 -C 18 alkylaryl radicals; and where R 1 , R 2 or both optionally are a hydrogen atom.
4. A procatalyst composition as defined in claim 1 , wherein the second internal electron donor has the following structure:
where R 1 -R 6 are the same or different and comprise a methyl, a C 2 -C 18 linear or branched alkyl, a C 3 -C 18 cycolalkyl, a C 4 -C 18 cycolalkyl-alkyl, a C 4 -C 18 alkyl-cycolalkyl, a phenyl, an organosilicon, a C 7 -C 18 arylalkyl, or a C 7 -C 18 alkylaryl radical, and where R 1 -R 4 are optionally a hydrogen atom or are combined to form one or more C 5 -C 7 fused aromatic or non-aromatic ring structures, optionally containing an N, O, or S heteroatom.
5. A procatalyst composition as defined in claim 1 , wherein the second internal electron donor comprises a bis(methoxymethyl)alkane.
6. A procatalyst composition as defined in claim 1 wherein the second internal electron donor comprises a substituted bis(methoxymethyl) cyclopentadiene.
7. A procatalyst composition as defined in claim 1 , wherein the second internal electron donor comprises 9,9-bis(methoxymethyl)fluorene.
8. A procatalyst composition as defined in claim 1 , wherein the second internal electron donor comprises 4,4-bis(methoxymethyl)-2,6-dimethyl heptane.
9. A procatalyst composition as defined in claim 1 , wherein the combined magnesium moiety, titanium moiety, and mixed internal electron donors form a substantially spherical shaped particle.
10. A procatalyst composition as defined in claim 1 , wherein the magnesium moiety comprises a magnesium-based spherical carrier.
11. A procatalyst composition as defined in claim 1 , wherein the substituted phenylene aromatic diester has the following structure:
where R 1 -R 4 are the same or different, each of R 1 -R 4 is selected from the group consisting of hydrogen, a substituted hydrocarbyl group having 1 to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinations thereof, and at least one of R 1 -R 4 is not hydrogen; and
at least one or two, or three, or four R groups of R 1 -R 4 is selected from a substituted hydrocarbyl group having 1 to 20 carbon atoms, an unsubstituted hydrocarbyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, a heteroatom, and combinations thereof, and where E 1 and E 2 are the same or different and selected from the group consisting of an alkyl having 1 to 20 carbon atoms, a substituted alkyl having 1 to 20 carbon atoms, an aryl having 1 to 20 carbon atoms, a substituted aryl having 1 to 20 carbon atoms, or a heteroatom containing functional group having 1 to 20 carbon atoms.
12. A catalyst system for the polymerization of propylene polymers comprising:
the procatalyst composition as defined in claim 1 ; and
a cocatalyst.
13. A catalyst system as defined in claim 12 , wherein the system further comprises an external electron donor.
14. A catalyst system as defined in claim 12 , further comprising an activity limiting agent.
15. A polymerization process comprising:
polymerizing an olefin in the presence of a catalyst composition comprising a Ziegler-Natta procatalyst composition, a cocatalyst composition, and optionally an external electron donor compound, the procatalyst composition formed from a transition metal compound and a mixture of internal electron donors comprising at least a first internal electron donor and a second internal electron donor, the first internal electron donor comprising a non-phthalate phenylene dicarboxylic acid ester, the second internal electron donor comprising a 1,3-diether.
16. A process as defined in claim 15 , wherein the process produces a polypropylene polymer.
17. A process as defined in claim 15 , wherein the second internal electron donor comprises the following structure:
where R 1 , R 2 , R 3 , and R 4 are the same or different and comprise a methyl, a C 2 -C 18 linear or branched alkyls, a C 3 -C 18 cycloalkyls, a C 4 -C 18 cycloalkyl-alkyls, a C 4 -C 18 alkyl-cycloalkyls, phenyl, an organosilicon, a C 7 -C 18 arylalkyls, or a C 7 -C 18 alkylaryl radicals and where R 1 , R 2 or both optionally are a hydrogen atom.
18. A process as defined in claim 15 , wherein the second internal electron donor comprises the following structure:
where R 1 -R 6 are the same or different and comprise a methyl, a C 2 -C 18 linear or branched alkyl, a C 3 -C 18 cycolalkyl, a C 4 -C 18 cycolalkyl-alkyl, a C 4 -C 18 alkyl-cycolalkyl, a phenyl, an organosilicon, a C7-C18 arylalkyl, or a C7-C18 alkylaryl radical, and where R 1 -R 4 are optionally a hydrogen atom or combined to form one or more C 5 -C 7 fused aromatic or non-aromatic ring structures, optionally containing an N, O, or S heteroatom.
19. A process as defined claim 15 , wherein the olefin comprises propylene and ethylene for forming a propylene and ethylene copolymer.
20. A process as defined in claim 15 , wherein the second internal electron donor comprises a bis(methoxymethyl)alkane, a substituted bis(methoxymethyl)cyclopentadiene, 9,9-bis(methoxymethyl)fluorene, and/or 4,4-bis(methoxymethyl)-2,6-dimethyl heptane.