Bridged metallocenes for olefin copolymerization

• US 6,528,670 B1
• Filed: 10/22/1999
• Issued: 03/04/2003
• Est. Priority Date: 10/23/1998
• Status: Expired due to Term

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Rix, Francis C.
• Primary Examiner(s): Shaver, Paul F.
• Application Number:
  US09/426,099
• Time in Patent Office: 1,229 Days
• Field of Search: 132/11, 526/126, 526/127
• US Class Current: 556/11
• CPC Class Codes: C07F 17/00 Metallocenes
• CPC Class Codes: C08F 10/02 Ethene
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 2/06 Organic solvent
• CPC Class Codes: C08F 210/14 Monomers containing five or more carbon atoms
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2420/10 Heteroatom-substituted bridge, i.e. Cp or analog where the bridge linking the two Cps or analogs is substituted by at least one group that contains a heteroatom
• CPC Class Codes: C08F 2500/03 Narrow molecular weight distribution, i.e. Mw/Mn < 3
• CPC Class Codes: C08F 2500/04 Broad molecular weight distribution, i.e. Mw/Mn > 6
• CPC Class Codes: C08F 2500/08 Low density, i.e. < 0.91 g/cm3
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 4/65904 in combination with another component of C08F4/64
• CPC Class Codes: C08F 4/65908 in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+
• CPC Class Codes: C08F 4/65925 two cyclopentadienyl rings being mutually non-bridged
• CPC Class Codes: C08F 4/65927 two cyclopentadienyl rings being mutually bridged

Abstract

The invention is directed to bridged metallocene catalyst complexes that are sufficiently soluble in aliphatic solvents to be particularly suitable for solution olefin polymerization processes such that olefin copolymers can be prepared with high molecular weights and catalyst activities particularly at high polymerization reaction temperatures. More specifically, the invention particularly relates to a polymerization process for ethylene copolymers having a density of about 0.850 to about 0.940 comprising contacting, under solution polymerization conditions at a reaction temperature at or above 60° C. to 250° C., ethylene and one or more comonomers capable of insertion polymerization with a bridged metallocene catalyst complex derived from two ancillary ligands, each of which independently may be substituted or unsubstituted, wherein the ligands are bonded by a covalent bridge containing a substituted single Group 14 atom, the substitution on said Group 14 atom comprising aryl groups at least one of which contains a hydrocarbylsilyl substituent; and B) an activating cocatalyst.

Claims

1. A Group 4 organometallic compound comprising two ancillary monanionic ligands, each of which independently may be substituted or unsubstituted, wherein the ligands are bonded by a covalent bridge containing a substituted single Group 14 atom, the substitution on said Group 14 atom comprising aryl groups at least one of which contains at least one hydrocarbylsilyl substituent group.

2. The compound of claim 1 wherein said hydrocarbylsilyl substituent has the formula R_n″

SiR′

<sub>3−

n</sub>, where each R′

is independently a C₁-C₂₀ hydrocarbyl, hydrocarbylsilyl, hydrofluorocarbyl substitutent, R″

is a C₁-C₁₀ linking group between Si and the aryl group, and n=0 or 1.

3. The organometallic compound of claim 2 wherein each R′

is a linear C₁-C₆ linear or branched alkyl substituent.

4. The organometallic compound of claim 3 wherein said catalyst compound is a hafnium organometallic compound and said substituted Group 14 atom is a carbon atom.

5. The organometallic compound of claim 4 wherein said compound is a biscyclopentadienyl hafnium organometallic compound having

i) at least one unsubstituted cyclopentadienyl or indenyl ligand,

ii) one aromatic fused-ring substituted cyclopentadienyl ligand.

6. The organometallic compound of claim 4 wherein said aromatic fused-ring substituted cyclopentadienyl ligand is a substituted or unsubstituted fluorenyl ligand.

7. The organometallic compound of claim 6 wherein said unsubstituted cyclopentadienyl ligand or aromatic fused-ring substituted cyclopentadienyl ligand is an unsubstituted cyclopentadienyl ligand.

8. The organometallic compound of claim 7 wherein said hafnium compound is selected from the group consisting of di(p-trimethylsilyl-phenyl)methylene(cyclopentadienyl)(fluorenyl)hafnium dimethyl, di(p-trimethylsilyl-phenyl)methylene (cyclopentadienyl)(2,7-dimethyl-9-fluorenyl)hafnium dimethyl and di(p-trimethylsilyl-phenyl)methylene(cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)hafnium dimethyl, di(p-triethylsilyl-phenyl)methylene(cyclopentadienyl)(fluorenyl)hafnium dimethyl, di(p-triethylsilyl-phenyl)methylene(cyclopentadienyl)(2,7-dimethyl-9-fluorenyl)hafnium dimethyl, di(p-triethylsilyl-phenyl)methylene (cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)hafnium dimethyl, (p-triethylsilyl-phenyl)(p-tert-butylphenyl)methylene(cyclopentadienyl)(fluorenyl)hafnium dimethyl, (p-triethylsilyl-phenyl))(p-n-butylphenyl)methylene(cyclopentadienyl)(2,7-dimethyl-9-fluorenyl)hafnium dimethyl, (p-trimethylsilylphenyl)(p-n-butylphenyl)methylene(cyclopentadienyl)(2,7-di-tert-butyl-9-fluorenyl)hafnium dimethyl, and (p-triethylsilyl-phenyl)(p-n-butylphenyl)methylene (cyclopentadienyl)(2,7-dimethyl-9-fluorenyl)hafnium dimethyl.