Catalyst system, the use thereof in the polymerization of...

Details Catalyst system, the use thereof in the polymerization of... Catalyst system, the use thereof in the polymerization of...

1999-08-10

2001-09-18

Wu, David W. (Department: 1711)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S127000, C526S943000, C526S335000, C526S340400, C502S104000, C502S152000

Reexamination Certificate

active

06291615

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a novel catalyst system, to the use thereof for the solution, suspension and vapour phase polymerization of dienes and to the use of the diene rubbers produced therewith, which have a high cis content, average vinyl content and low gel content.
BACKGROUND OF THE INVENTION
The preparation of polydienes, e.g. cis-polybutadiene (BR), on the basis of metal-organic Ziegler-Natta catalysts is a process which has been used on the industrial scale for a long time. The commercially available grades are characterized by different microstructures. The high-cis grades have cis contents of over 90% and vinyl contents of up to 4%: Nd—BR (97% cis, 2% trans, 1% vinyl), Ni—BR (96% cis, 2% trans, 2% vinyl), Co—BR (95% cis, 3% trans, 2% vinyl), Ti—BR (92% cis, 4% trans, 4% vinyl) (Ullmanns Encyklopädie der technischen Chemie (Ullmann's Encyclopaedia of Chemical Technology), Verlag Chemie, Weinheim, 4th edition, volume 13, pages 602-604; “Handbuch für die Gummi-Industrie” (“Handbook for the Rubber Industry”), Bayer AG, 2nd edition, chapter A8.1).
Li—BR, on the other hand, is prepared by an anionic process using lithium alkyl catalysts. The trans content exceeds the cis content in this case (35% cis, 55% trans, 10% vinyl).
It is further known that high-cis diene rubbers with vinyl contents of >10% can be prepared using metal-organic catalyst systems, especially metallocenes, e.g. cyclo-pentadienyltitanium trichloride (CpTiCl
3
)/methylaluminoxane (MAO) (L. Oliva, P. Longo, A. Grassi, P. Ammendola, C. Pellecchia, MaKromol. Chem., Rapid Commun. 11 (1990) 519-524) or cyclopentadienyltributoxytitanium/MAO (G. Ricci, L. Porri, A. Giarrusso, Macromol. Symp. 89 (1995) 383-392).
It is also known to polymerize conjugated dienes in the liquid monomers without the addition of solvents. However, such a process has the disadvantage that complete polymerization is accompanied by the evolution of a large quantity of heat, which is difficult to regulate and is therefore potentially hazardous. Moreover, this process also causes environmental pollution when the polymers are separated from the monomers.
In recent years the vapour phase process has proved particularly advantageous especially for the preparation of polyethylenes and polypropylenes and has achieved industrial success. The environmentally relevant advantages of the vapour phase process are based especially on the fact that no solvents are used and emissions and effluent pollution can be reduced.
EP 647 657 discloses a catalyst system which polymerizes butadiene to very high-cis polybutadiene in the vapour phase. It is further known that a system consisting of CpTiCl
3
and MAO is capable of polymerizing butadiene without a solvent (WO 96/04322).
The main areas of application for polybutadiene are tyre manufacture, industrial rubber goods and the modification of plastics.
In tyre manufacture, it is known that the various components, such as tread, side wall, steel belt plies, carcass and heel, are made into the blank and then vulcanized. A high cis content therefore has a positive effect in tyre manufacture because of the compounding adhesiveness and unvulcanized strength (“Kunststoffe und Elastomere in Kraftfahrzeugen” (“Plastics and Elastomers in Motor Vehicles”), G. Walter, Verlag W. Kohlhammer Stuttgart, Berlin, Cologne, Mainz, 1985, chapter 4.7.17; “Handbuch für die Gummi-Industrie” (“Handbook for the Rubber Industry”), Bayer A G, 2nd edition, chapter A8.1).
On the other hand it is known that increasing the vinyl content improves certain properties of the tyre, especially the wet grip. Improving the wet grip ensures greater safety on the road.
For conventional tread compounds, however, an improvement in wet grip is accompanied by a decrease in rolling resistance and hence an increase in motor vehicle fuel consumption and emissions. It has been found that the rolling resistance can be correlated well with the loss factor tan &dgr; recorded at a frequency of 10 Hz and a temperature of 60° C., a drop in the loss factor at 60° C. being accompanied by a decrease in rolling resistance (K. H. Nordsiek, Kautschuk, Gummi, Kunststoffe 39 (1986) 599-611; R. Bond, G. F. Morton, L. H. Krol, Polymer 25 (1984) 132-140).
It is known that tyre properties can be adjusted by compounding various types of synthetic rubber. However, this process is expensive and the problem of phase separation can arise during compounding.
SUMMARY OF THE INVENTION
The object consists in providing a novel catalyst system for the production, in solution, suspension and vapour phase processes, of diene rubbers with a high cis content, average vinyl content and low gel content which have a lower loss factor tan &dgr; at 60° C. (rolling resistance) in rubber compounds, said catalyst system not possessing the disadvantages of the state of the art.
Surprisingly it has now been found that diene rubbers can be produced in high space-time yields by using a fluorine-containing metal-organic compound together with a co-catalyst, and that diene rubbers with low gel contents can be produced in high space-time yields by heterogenizing a fluorine-containing metal-organic compound together with a co-catalyst on an inorganic support and using it in vapour phase polymerization.
Furthermore it has now been found that diene rubbers which have a high cis content and average vinyl content and have a lower loss factor tan &dgr; at 60° C. as well as high elasticity in rubber compounds, and which are thus outstandingly suitable as raw materials in the tyre sector for use in treads and side walls, can be produced in high space-time yields by means of metal-organic catalysts in a one-stage process.
DETAILED DESCRIPTION OF THE INVENTION
Said object is achieved according to the invention by the use of novel, highly active metal-organic catalysts of formula 1:
R
n
MX
m
  (1),
wherein M is a metal, the radicals R are identical or different, can be in a bridged or unbridged form and are a mononuclear or polynuclear hydrocarbon radical coordinated with the central atom M, the radicals X are identical or different and are a fluorine, chlorine, bromine or iodine, a hydrogen radical, C
1
- to C
10
-alkyl, C
6
- to C
15
-aryl, OR′ or OC(O)R′, R′ being C
1
- to C
10
-alkyl, C
6
- to C
15
-aryl, alkylaryl, fluorine, fluoroalkyl or fluoroaryl each having 1 to 10 C atoms in the alkyl moiety and 6 to 20 C atoms in the aryl moiety, and n and m each denote the numbers 0, 1, 2, 3 or 4, where n+m<5.
M is preferably titanium, zirconium, hafnium, vanadium, niobium, tantalum, scandium, yttrium or a rare earth metal, particularly preferably titanium.
X is preferably fluorine or a mixture of fluorine and chlorine, bromine or iodine.
n is preferably 1 or 2, m is preferably 3, 2 or 1 and m+n is preferably 3 or 4.
n is particularly preferably 1, m is particularly preferably 3 and m+n is particularly preferably 4.
R is preferably a substituted or unsubstituted cyclopentadienyl group (R″)
k
Cp, R″ being a hydrogen radical, C
1
- to C
10
-alkyl, C
6
- to C
15
-aryl, arylalkyl, alkenyl, fluoroalkyl or fluoroaryl and k is 1-5.
Examples of substituted cyclopentadienyl groups are methylcyclopentadienyl, dimethylcyclopentadienyl, trimethylcyclopentadienyl, pentamethylcyclopentadienyl, ethylcyclopentadienyl, diethylcyclopentadienyl, triethylcyclopentadienyl, tetraethyl-cyclopentadienyl, pentaethylcyclopentadienyl, propylcyclopentadienyl, phenylcyclopentadienyl, ethyltetramethylcyclopentadienyl, propyltetramethylcyclopentadienyl, butyltetramethylcyclopentadienyl, silylcyclopentadienyl, indenyl, methylindenyl, dimethylindenyl, benzindenyl, methylbenzindenyl, dimethylbenzindenyl and trimethylbenzindenyl.
Examples of particularly preferred compounds of formula 1 are:
CpTiF
3
MeCpTiF
3
Me
5
CpTiF
3
(Me
5
Cp)
2
TiF
IndTiF
3
IndTiClF
2
IndTiCl
2
F
MeIndTiF
3
MeIndTiClF
2
MeIndTiCl
2
F
Me
2
IndTiF
3
BenzindTiF
3
MeBenzindTiF
3
Co-catalysts which can be used in the process according to the invention are alkylaluminoxanes, butyl-

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