Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Polymers from only ethylenic monomers or processes of...
Reexamination Certificate
2000-08-15
2002-02-05
Teskin, Fred (Department: 1713)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Polymers from only ethylenic monomers or processes of...
C526S129000, C526S164000, C526S172000, C526S335000, C526S340400, C526S901000, C526S903000
Reexamination Certificate
active
06344527
ABSTRACT:
This invention relates to a process for the production of polydienes having controlled Mooney viscosity which is carried out in the presence of metal catalysts of the rare earths and in the presence of specific molecular-weight controllers. The polydienes produced in this way are used in particular in the manufacture of car tires.
EP 0 647 657 discloses, inter alia, a process for the production of polydienes, according to which conjugated dienes are polymerised in the vapour phase by means of a supported catalyst based on rare earth compounds.
Furthermore, EP 0 736 549 discloses a process for the production in the vapour phase of diene rubbers, in which in the first step the dienes or mixtures of dienes are polymerised in a special way in the presence of a catalyst of the rare earths, so that a pourable diene rubber having a defined Mooney viscosity is obtained, and then in a second step the pourable diene rubber obtained is subjected in conventional manner to a degradative reaction, until a decreased Mooney viscosity is attained. The process described in EP 0 736 549 affords the possibility of producing diene rubbers with desired Mooney viscosities depending on the field of application, which have defined Mooney viscosities appropriate to the desired field of application.
Although the process described in EP 0 736 549 yields good results as regards the Mooney viscosities attainable in the diene rubbers, a technically simpler, more economical method of molecular weight control in the vapour phase process would be desirable.
Such a molecular weight control can be effected economically, in a technically simpler way, by the process according to the invention described in more detail below.
The present invention accordingly provides a process for the production of polydienes having controlled Mooney viscosity, carried out by means of catalysts based on rare earth compounds, which is characterised in that the conjugated dienes used are polymerised in the presence of from 0.005 to 80 wt. % of 1,2-dienes, based on the sum of conjugated dienes used and of 1,2-ienes used.
Examples of suitable conjugated dienes which can be used in the vapour phase process according to the invention, are 1,3-butadiene, isoprene, pentadiene and/or dimethylbutadiene, in particular 1,3-butadiene and isoprene. In the process according to the invention it is, of course, also possible to carry out the polymerisation in the presence of other monomers such as, for example, ethylene, propylene, butene, isobutylene, methylpentene, norbornene, cyclopentadiene, cyclohexene, styrene or chloroprene.
The quantities used of these monomers can vary within wide limits. In general, the quantity of additional monomers used is from 0.01 to 200 wt. %, based on conjugated diene used, preferably from 0.1 to 20 wt. %.
The 1,2-dienes used in order to control the Mooney viscosities are introduced in quantities of from 0.005 to 80 wt. %, preferably from 0.01 to 30, and particularly preferably from 0.05 to 10 wt. %, based on the sum of the conjugated dienes used and of 1,2-dienes used.
The required quantity of the controller according to the invention is dependent on various factors, for example, on the quantity of the catalysts used, the nature of the monomers used, the proportion of monomers in the reaction mixture, the reaction temperature and the pressure. It is easily possible, by appropriate preliminary experiments, to determine in each case the most suitable quantity of controller for the desired Mooney viscosity of the polymer.
Suitable 1,2-dienes are in particular those having boiling points below 140° C., preferably below 80° C., such as allene, 1,2-butadiene and 1,2-pentadiene or mixtures containing these 1,2-dienes.
The quantities, already specified above, of 1,2-dienes to be used are average values, that is, quantities which apply to the entire course of the reaction. This means, for example, that the controller according to the invention can be added in its entirety at the beginning of the polymerisation reaction, continuously throughout the whole course of the polymerisation or intermittently.
The process according to the invention is generally carried out at temperatures of from −20° C. to 250° C., preferably 20° C. to 160° C., particularly preferably 50° C. to 120° C., and at pressures of from 1 mbar to 50 bar, preferably at 0.5 to 30 bar, particularly preferably at 1 to 20 bar.
As already mentioned above, the process according to the invention is carried out in the presence of specially supported catalysts based on rare earth compounds. In this connection, the authors would also refer to the patent literature also already mentioned above, in which such catalysts are described and claimed.
The rare earth metal catalysts to be used for the process according to the invention consist, for example, of:
A) an alcoholate of the rare earths (I), a carboxylate of the rare earths (II), a complex compound of the rare earths with diketones (III) and/or an addition compound of the halides of the rare earths with an oxygen-donating compound or nitrogen-donating compound (IV) corresponding to the following formulae:
(RO)
3
M (I),
(R—CO
2
)
3
M (II),
(RCOCHCOR)
3
M (III)
and
MX3×y donor (IV),
B) an aluminiumtrialkyl, a dialkylaluminium hydride and/or an alumoxan corresponding to formulae (V) to (VII):
Al R
3
(V),
HAlR
2
(VI),
R(AlO)
n
AlR
2
(VII)
wherein in the formulae
M denotes a trivalent element from among the rare earths having the atomic numbers 21, 39 or 57 to 71,
R is identical or different and denotes alkyl groups having 1 to 10 carbon atoms,
X represents chlorine, bromine or iodine
y denotes 1 to 6 and
n denotes 1 to 50,
C) another Lewis acid and
D) an inert, particulate solid having a specific surface of greater than 10 m
2
/g (BET) and a pore volume of 30 to 1,500 ml/g.
In component A, M denotes a trivalent element from among the rare earths having the atomic numbers 21, 39 or 57 to 71 according to the periodic system. Preferred compounds are those in which M denotes lanthanum, cerium, praseodymium or neodymium or a mixture of rare earth elements which contains at least one of the elements lanthanum, cerium, praseodymium or neodymium in a proportion of at least 10 wt. %. Compounds in which M denotes lanthanum or neodymium or a mixture of rare earths which contains at least 30 wt. % lanthanum or neodymium are particularly preferred.
Examples of groups R in formulae (I) to (IV) to be mentioned are in particular straightchain or branched alkyl groups having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, isopropyl, isobutyl, tert. butyl, 2-ethylhexyl, neopentyl, neooctyl, neodecyl and neododecyl.
Examples to be mentioned of alcoholates used as component A are: neodymium(III) n-propanolate, neodymium(III) n-butanolate, neodymium(III) n-decanolate, neodyrnium(III) isopropanolate, neodymium(III) 2-ethylhexanolate, praseodymium(III) n-propanolate, praseodymium(III) n-butanolate, praseodymium(III) n-decanolate, praseodymium(III) isopropanolate, praseodymium(III) 2-ethylhexanolate, lanthanum(III) n-propanolate, lanthanum(III) n-butanolate, lanthanum(III) n-decanolate, lanthanum(III) isopropanolate, lanthanum(III) 2-ethylhexanolate, preferably neodymium(III) n-butanolate, neodymium(III) ndecanolate, neodymium(III) 2-ethylhexanolate.
The following carboxylates are suitable for use as component A: lanthanum(III) propionate, lanthanum(III) diethylacetate, lanthanum(III) 2-ethylhexanoate, lanthanum(III) stearate, lanthanum(III) benzoate, lanthanum(III) cyclohexanecarboxylate, lanthanum(III) oleate, lanthanum(III) versatate, lanthanum(III) naphthenate, praseodymium(III) propionate, praseodymium(III) diethylacetate, praseodymium(III) 2-ethylhexanoate, praseodymium(III) stearate, praseodymium(III) benzoate, praseodymium(III) cyclohexanecarboxylate, prascodymium(III) oleate, praseodymium(III) versatate, praseodymium(III) napbthenate, neodymium(III) propionate, neodymium(III)
Marwede Günter
Sylvester Gerd
Bayer Aktiengesellschaft
Cheung Noland J.
Gil Joseph C.
Teskin Fred
LandOfFree
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