Method for producing very-high or ultra-high molecular weight polyethylene
View Patent ↗The field of the invention relates generally to a method for preparing very-high or ultra-high molecular weight polyethylene. More particularly, the present invention related to a method of preparing very-high or ultra-high molecular weight polyethylene using a supported catalyst comprising a support, an activator and a metal-ligand complex, as well as the catalyst itself. The present invention additionally relates to a method of using a supported catalyst comprising a support, an activator and co-supported metal-ligand complexes to obtain a bi-modal molecular weight distribution of polyethylene.
1. A slurry polymerization method for producing a very-high or ultra-high molecular weight polyethylene composition, the method comprising contacting one or more monomers with a supported catalyst, the supported catalyst comprising:
a support,
a metal-ligand complex deposited on the support at a loading from about 1 μmol/gram of supported catalyst to about 100 μmol/gram of supported catalyst, the metal-ligand complex characterized by the general formula:
wherein the O-AR-AR-O—B—O-AR-AR-O fragment of the general formula is defined by a ligand selected from the group consisting of
wherein at least two of the bonds from the oxygens (O) to M are covalent, with the other bonds being dative; M is a metal selected from the group consisting of Hf and Zr; each L is independently a moiety that forms a covalent dative or ionic bond with M; and n′ is 1, 2, 3 or 4; and,
an activator.
2. A method as set forth in claim 1 wherein the support is selected from the group consisting of silicas, aluminas, clays, zeolites, magnesium chloride, polystyrenes and substituted polystyrenes.
3. A method as set forth in claim 1 wherein the loading of the metal-ligand complex deposited on the support is from about 1 μmol/gram of supported catalyst to about 50 μmol/gram of supported catalyst.
4. A method as set forth in claim 1 wherein the polyethylene composition is an ultra-high molecular weight polyethylene composition with a weight average molecular weight of between about 3×10 6 g/mol and about 20×10 6 g/mol.
5. A method as set forth in claim 1 wherein the polyethylene composition is an ultra-high molecular weight polyethylene composition with a weight average molecular weight of between about 3×10 6 g/mol and about 15×10 6 g/mol.
6. A method as set forth in claim 1 wherein the polyethylene composition is an ultra-high molecular weight polyethylene composition with a weight average molecular weight of between about 3×10 6 g/mol and about 10×10 6 g/mol.
7. A method as set forth in claim 1 wherein the polyethylene composition is a very-high molecular weight polyethylene composition with a weight average molecular weight of between about 1×10 6 g/mol and about 3×10 6 g/mol.
8. A method as set forth in claim 1 wherein the polyethylene composition is a very-high molecular weight polyethylene composition with a weight average molecular weight of between about 2×10 6 g/mol and about 3×10 6 g/mol.
9. A method as set forth in claim 1 wherein at least two monomers are contacted with the supported catalyst.
10. A method as set forth in claim 9 wherein at least one of the monomers is ethylene and one of the monomers is an α-olefin.
11. A slurry polymerization method for producing a very-high or ultra-high molecular weight polyethylene composition, the method comprising contacting one or more monomers with a supported catalyst, the supported catalyst comprising:
a support,
a metal-ligand complex deposited on the support at a loading from about 1 μmol/gram of supported catalyst to about 100 μmol/gram of supported catalyst, the metal-ligand complex characterized by the general formula:
wherein at least two of the bonds from the oxygens ( 0 ) to M are covalent, with the other bonds being dative; and
wherein each of R 2 and R 12 is
each of R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , R 13 , R 14 , R 15 , R 16 , R 17 , R 18 and R 19 is independently selected from the group consisting of hydrogen, halogen, and optionally substituted hydrocarbyl, heteroatom-containing hydrocarbyl, alkoxy, aryloxy, silyl, boryl, phosphino, amino, alkylthio, arylthio, nitro, and combinations thereof; optionally two or more R groups can combine together into ring structures, with such ring structures having from 3 to 12 atoms in the ring, not counting hydrogen atoms; B is a bridging group having from 3 to 50 atoms not counting hydrogen atoms and is selected from the group consisting of optionally substituted divalent hydrocarbyl and optionally substituted divalent heteroatom-containing hydrocarbyl; M is a metal selected from the group consisting of Hf and Zr; each L is independently a moiety that forms a covalent dative or ionic bond with M; and n′ is 1, 2, 3 or 4;
wherein the O—B—O fragment is:
wherein each Q is independently selected from the group consisting of carbon and silicon, each R 60 is independently selected from the group consisting of hydrogen and optionally substituted hydrocarbyl and heteroatom containing hydrocarbyl, provided that at least one R 60 substituent is not hydrogen, wherein the R 60 substituents are optionally joined into a ring structure having from 3 to 50 atoms in the ring structure not counting hydrogen atoms, and m′ is 0, 1, 2 or 3; and,
an activator.