Olefin polymerization process

Details Olefin polymerization process Olefin polymerization process

2002-09-27

2004-07-20

Wu, David W. (Department: 1713)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S161000, C526S172000, C526S134000, C526S127000, C526S129000, C526S130000

Reexamination Certificate

active

06765074

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a process for polymerizing olefins. The process is performed in the presence of a supported indenoindolyl-containing catalyst system and an organoboron or organoaluminum-treated solid. The presence of the organoboron or organoaluminum-treated solid surprisingly leads to an increased activity compared to polymerization processes performed without it.
BACKGROUND OF THE INVENTION
Many olefin polymerization catalysts are known, including conventional Ziegler-Natta catalysts. While these catalysts are inexpensive, they exhibit low activity, produce polymers having narrow to medium molecular weight distributions (M
w
/M
n
>4), and are generally poor at incorporating &agr;-olefin comonomers. To improve polymer properties, highly active single-site catalysts, in particular metallocenes, are beginning to replace Ziegler-Natta catalysts. Although more expensive, the new catalysts give polymers with narrow molecular weight distributions, and good comonomer incorporation, which allows easier production of low-density polymers. One disadvantage of metallocene catalysts is that they tend to produce lower molecular weight polymers at higher temperatures.
Recent attention has focused on developing improved single-site catalysts in which a cyclopentadienyl ring ligand is replaced by a heteroatomic ring ligand. These catalysts may be referred to generally as “heterometallocenes.” One particular type of heterometallocene of interest contains an indenoindolyl ligand as disclosed in U.S. Pat. No. 6,232,260 and PCT Int. Appl. WO 99/24446.
Single-site catalysts are typically soluble in the polymerization reaction medium and are therefore valuable for solution processes. However, for gas-phase, slurry, and bulk monomer processes, it is useful to immobilize the catalyst on a carrier or support in order to control polymer morphology. U.S. Pat. No. 6,211,311 teaches support chemical pretreatment for supported single-site catalysts that contain a polymerization-stable heteroatomic ligand. For catalysts containing indenoindolyl ligands, both U.S. Pat. No. 6,232,260 and PCT Int. Appl. WO 99/24446 disclose that a support such as silica or alumina can be used. Increasing the activity of the polymerization process is an important objective in order to achieve an economical process. As with any chemical process, it is desirable to develop new polymerization methods and catalysts.
In sum, new olefin polymerization processes using supported indenoindolyl-containing catalysts are needed. Particularly valuable processes would have improved catalyst activity.
SUMMARY OF THE INVENTION
The invention is a process for polymerizing olefins. The process is performed in the presence of a supported indenoindolyl-containing catalyst system and an organoboron or organoaluminum-treated solid. The supported indenoindolyl catalyst system comprises a support, an organometallic complex comprising a Group 3 to 10 transition or lanthanide metal, M, and at least one indenoindolyl ligand that is &pgr;-bonded to M, and an activator. The presence of the organoboron or organoaluminum-treated solid surprisingly leads to an increased activity compared to polymerization processes that do not use the treated solid. In addition, the presence of the treated solid enhances catalyst operability by reducing the incidence of reactor fouling.
DETAILED DESCRIPTION OF THE INVENTION
The process of the invention comprises polymerizing one or more olefins in the presence of a supported indenoindolyl catalyst system. Supported indenoindolyl-containing catalyst systems include an indenoindolyl-containing complex, an activator, and a support.
The supported catalyst system of the invention contains an organometallic complex comprising a Group 3 to 10 transition or lanthanide metal, M, and at least one indenoindolyl ligand that is &pgr;-bonded to M. The metal, M, may be any Group 3 to 10 transition or lanthanide metal. Preferably, the catalyst contains a Group 4 to 6 transition metal; more preferably, the catalyst contains a Group 4 metal such as titanium or zirconium.
The organometallic complex of the invention also contains at least one indenoindolyl ligand that is &pgr;-bonded to M. Indenoindolyl ligands are well-known in the art and are taught in U.S. Pat. No. 6,232,260, the teachings of which are incorporated herein by reference. The indenoindolyl ligand is an anionic ligand derived from an indenoindole. An indenoindole is an organic compound that has both indole and indene rings. The five-membered rings from each are fused, i.e., they share two or more carbon atoms. Any of the indenoindolyl ring atoms can be unsubstituted or substituted with one or more groups such as alkyl, aryl, aralkyl, halogen, silyl, nitro, dialkylamino, diarylamino, alkoxy, aryloxy, thioether, or the like. Additional rings can be present, as long as an indenoindole moiety is present.
Suitable indenoindole ligand precursors include, for example, 5,10-dihydroindeno[3,2-b]indole, 4,8,10-trimethyl-5H-indeno[3,2-b]indole, 4-tert-butyl-8-methyl-5,10-dihydroindeno[3,2-b]indole, 4,8-dichloro-5,10-dihydroindeno[3,2-b]indole, 10-methylbenzo[f]-5H-indeno[3,2-b]indole, benzo[g]-5,10-dihydroindeno[3,2-b]indole, 5,10-dihydroindeno[3,2-b]benzo[e]indole, benzo[g]-5,10-dihydroindeno[3,2-b]benzo[e]indole, and the like.
The indenoindolyl ligand is generated by deprotonating a ligand precursor with a base to give an anionic ring system with a high degree of aromaticity (highly delocalized). Reaction of the anion with, e.g., a transition metal halide gives the desired organometallic complex. The indenoindolyl ligand is &pgr;-bonded to M in the complex.
The organometallic complex optionally includes one or more additional polymerization-stable, anionic ligands. Examples include substituted and unsubstituted cyclopentadienyl, fluorenyl, and indenyl, or the like, such as those described in U.S. Pat. Nos. 4,791,180 and 4,752,597, the teachings of which are incorporated herein by reference. Suitable ligands also include substituted and unsubstituted boraaryl, pyrrolyl, indolyl, quinolinyl, pyridinyl, and azaborolinyl as described in U.S. Pat. Nos. 5,554,775, 5,539,124, 5,637,660, and 5,902,866, the teachings of which are also incorporated herein by reference. The organometallic complex also usually includes one or more labile ligands such as halides, alkoxys, siloxys, alkyls, alkaryls, aryls, dialkylaminos, or the like. Particularly preferred are halides, alkyls, and alkaryls (e.g., chloride, methyl, benzyl).
The indenoindolyl and/or polymerization-stable ligands can be bridged. Groups that can be used to bridge the ligands include, for example, methylene, ethylene, 1,2-phenylene, dialkylsilyls, and diarylsilyls. Normally, only a single bridge is included, but complexes with two bridging groups can be used. Bridging the ligand changes the geometry around the transition metal and can improve catalyst activity and other properties, such as molecular weight, comonomer incorporation, and thermal stability.
Suitable activators include alumoxanes. Preferred alumoxanes are polymeric aluminum compounds represented by the cyclic formula (R
1
—Al—O)
s
or the linear formula R
1
(R
1
—Al—O)
s
AlR
1
wherein R
1
is a C
1
-C
5
alkyl group and s is an integer from 1 to about 20. Preferably, R
1
is methyl and s is from about 4 to about 20. Exemplary alumoxane activators are (poly)methylalumoxane (MAO), ethylalumoxane, and diisobutylalumoxane. Optionally, the activator is a trialkyl or triaryl aluminum compound, which preferably has the formula AlR
2
3
where R
2
denotes a C
1
-C
20
hydrocarbyl.
Suitable activators also include substituted or unsubstituted trialkyl or triaryl boron derivatives, such as tris(perfluorophenyl)boron, and ionic borates such as tri(n-butyl)ammonium tetrakis(pentafluorophenyl) boron or trityl tetrakis(pentafluorophenyl) boron. The ionic borates ionize the neutral organometallic compound to produce an active c

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