Composition based on fluorine-containing metal complexes

Details Composition based on fluorine-containing metal complexes Composition based on fluorine-containing metal complexes

1999-09-17

2001-10-16

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...

C526S132000, C526S943000, C526S348000, C502S152000

Reexamination Certificate

active

06303718

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a catalyst system based on fluorine-containing metal complexes, particularly a catalyst system consisting of metallocene fluorides and aluminum alkyls, and relates to the use of said catalyst system for the polymerization of unsaturated compounds, particularly for the polymerization and copolymerization of olefins and/or dienes.
BACKGROUND OF THE INVENTION
The use of metal cyclopentadienyl complexes for the polymerization of olefins and diolefins, particularly the use of metallocene complexes in admixture with activating co-catalysts, has long been known.
U.S. Pat. No. 2,827,446 describes a catalyst which is prepared from titanocene dichloride and diethylaluminum chloride for the polymerization of ethylene. However, this catalyst is unsuitable for industrial use, since first, the activity of the catalyst is too low and second, the polymerization of 1-olefins is not possible.
Highly effective, specific catalyst systems are known for the (co)polymerization of ethylene and/or 1-olefins. These catalysts consist of metallocene dichlorides in admixture with aluminoxanes, e.g. methylaluminoxane (MAO). In order to increase the activity and selectivity of the catalyst and in order to control the microstructure, molecular weight and molecular weight distribution of the products, a multiplicity of new metallocene catalysts or metallocene catalyst systems has been developed in recent years for the polymerization of olefinic compounds (e.g. EP 69,951, 129,368, 347,128, 347,129, 351,392, 485,821, 485,823). Chlorine-containing metallocenes are usually employed in combination with MAO.
Methods of polymerizing olefins are also known in which metallocene/aluminoxane catalysts (e.g. EP 308,177) are produced in situ.
In WO 97/07141, fluorine-containing semi-sandwich complexes of titanium are used in combination with MAO as catalysts for the production of polystyrene. WO 98/36004 describes fluorine-containing complexes, preferably of titanium, and preferably in combination with MAO, as catalysts for the production of polybutadiene.
However, the catalyst systems based on aluminoxanes, e.g. MAO, which were described above have disadvantages which are described in greater detail below. MAO is a mixture of different aluminum compounds, the number and structure of which are not known accurately. The polymerization of olefins with catalyst systems which contain MAO is therefore, not always reproducible. Moreover, MAO is not stable on storage and its composition changes under the effect of thermal stresses. MAO has the disadvantage of having to be used in considerable excess in order to achieve high catalyst activities and this results in a high content of aluminum in the polymer. MAO is also a cost-determining factor. Considerable excesses of MAO are uneconomic for industrial use.
In order to circumvent these disadvantages, aluminoxane-free polymerization catalysts have been developed in recent years. For example, Jordan, et al. in J. Am. Chem. Soc., Vol. 108 (1986), 7410 describe a cationic zirconocene-methyl complex which contains tetraphenylborate as a counterion and which polymerizes ethylene in methylene chloride. EP-A 277,003 and EP-A 277,004 describe ionic metallocenes which are prepared by the reaction of metallocenes with ionizing reagents. EP-A 468,537 describes catalysts which possess an ionic structure and which are prepared by the reaction of metallocene dialkyl compounds with tetrakis(pentafluorophenyl)boron compounds. Ionic metallocenes are suitable as catalysts for the polymerization of olefins. One disadvantage, however, is the high sensitivity of these catalysts to impurities, such as moisture and oxygen, for example.
Prior art methods of preparing cationic metallocene complexes also have the disadvantage that the reagents which result in cation formation, e.g. tetrakis(pentafluorophenyl)boron compounds, are sometimes costly to synthesize, and the use thereof is expensive.
In addition, methods are known for the polymerization of olefins in which metallocene dialkyl compounds (EP 427,697) or metallocene dichlorides (WO 92/01723), each in combination with aluminum alkyls and a third component, e.g. tris(pentafluorophenyl)boron compounds, are used as catalyst systems. Metallocene dichlorides or metallocene dialkyls in combination with aluminum alkyls alone, are not active with regard to polymerization.
SUMMARY OF THE INVENTION
The object of the present invention was to identify an aluminoxane-free composition which avoids the disadvantages of the prior art, and the use of which, despite this, enables high polymerization activities to be achieved. A further object was to identify an aluminoxane-free catalyst system for the production of polyolefin rubbers, particularly EP(D)M.
Surprisingly, it has now been found that catalyst systems based on fluorine-containing metal complexes are particularly suitable for achieving the aforementioned object.
DETAILED DESCRIPTION OF THE INVENTION
The present invention therefore relates to an aluminoxane-free catalyst system consisting of
a) a fluorine-containing metal complex of formula (I)
A
a
MF
b
L
c
  (I)
 wherein
M is a metal selected from the group consisting of zirconium, hafnium, vanadium, niobium and tantalum,
A denotes an anionic ligand which is optionally singly- or multiply-bridged,
F denotes a fluorine atom,
L is a nonionic ligand,
a is 1 or 2,
b is 1, 2 or 3, and
c is 0, 1, 2, 3 or 4, particularly 1, 2 or 3,
wherein a+b=3 or 4 if M is zirconium or hafnium, a+b=3, 4 or 5 if M=vanadium, niobium or tantalum, and
b) a compound of formula (II)
M′Y
3
  (II)
 wherein
M′ denotes boron or aluminum, and
Y denotes entities which are the same or different, and represents hydrogen, a linear or branched C
1
to C
20
alkyl group which is optionally substituted by silyl groups, a linear or branched C
1
to C
10
fluoroalkyl group, a C
6
to C
10
fluoroaryl group, a C
1
to C
10
alkoxy group, a C
6
to C
20
aryl group, a C
6
to C
20
aryloxy group, a C
7
to C
40
arylalkyl group, or a C
7
to C
40
alkylaryl group,
wherein trimethylaluminum is excluded.
Fluorine-containing metal complexes of formula (I) which are particularly suitable are those in which
A is
a pyrazolyl borate of formula R
1
B(N
2
C
3
R
2
3
)
3
,
an alcoholate or phenolate of formula OR
1
,
a thiolate of formula SR
1
,
an amide of formula NR
1
2
,
a siloxane of formula OSiR
1
3
,
an acetylacetonate of formula (R
1
CO)
2
CR
1
,
an amidinate of formula R
1
C(NR
1
)
2
,
a cyclooctatetraenyl of formula C
8
H
q
R
1
8-q
where q represents 0, 1, 2, 3, 4, 5, 6 or 7,
a cyclopentadienyl of formula C
5
H
q
R
1
5-q
where q represents 0, 1, 2, 3,4 or 5,
an indenyl of formula C
9
H
7-r
R
1
r
where r represents 0, 1, 2, 3, 4, 5, 6 or 7,
a fluorenyl of formula C
13
H
9-s
R
1
s
where s represents 0, 1, 2, 3, 4, 5, 6, 7, 8 or 9,
a C
1
to C
20
alkyl radical, a C
6
to C
10
aryl radical, or a C
7
to C
40
alkylaryl radical,
 wherein
R
1
denotes entities which are the same or different, and represents hydrogen, a C
1
to C
20
alkyl group, a C
6
to C
10
fluoroaryl group, a C
1
to C
10
alkoxy group, a C
6
to C
20
aryl group, a C
6
to C
10
aryloxy group, a C
2
to C
10
alkenyl group, a C
7
to C
40
arylalkyl group, a C
7
to C
40
alkylaryl group, a C
8
to C
40
arylalkenyl group, a C
2
to C
10
alkynyl group, a silyl group which is optionally substituted by C
1
-C
10
hydrocarbon radicals, a boryl group, an amino group or a phosphinyl group, or denote adjacent R
1
radicals which form a ring system with the atoms linking them,
R
2
represents hydrogen or a C
1
-C
10
alkyl group, and M, F, L and a, b, c have the meanings given above.
Examples of suitable nonionic ligands include ethers, thioethers, cyclic ethers, cyclic thioethers, amine or phosphines. Other examples of nonionic ligands include substituted or unsubstituted aromatic compounds, such as benzene, toluene, dimethylbenzene, trimethylbenzene, pentafluorobenzene, trifluoromethylbenzene, bis(trif

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