Catalyst system for gas phase polymerization of conjugated...

Details Catalyst system for gas phase polymerization of conjugated... Catalyst system for gas phase polymerization of conjugated...

2000-07-13

2003-06-10

Choi, Ling-Siu (Department: 1713)

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

Synthetic resins

Polymers from only ethylenic monomers or processes of...

C526S335000, C502S117000, C502S116000, C502S103000, C502S120000

Reexamination Certificate

active

06576727

ABSTRACT:

The invention relates to a catalyst system for the gas-phase polymerization of conjugated dienes, consisting of a rare earth compound, an organoaluminium compound, a further Lewis acid, optionally a conjugated diene, an inert, inorganic or organic support material and, additionally, a co-catalyst applied to an inorganic or organic support material, with an improvement in the flowability of the rubber produced thereby.
Polybutadiene having a high content of cis-1,4 units has for a long time been produced on a commercial scale and used in the manufacture of tires and other rubber products.
For environmental reasons, attempts are being made to carry out the polymerization of this and other conjugated dienes in the gas phase, since no solvents have to be used in that case and emission and waste water pollution can be reduced.
In addition, novel rubbers having particular product properties can be produced by the process. In particular, fillers dispersed especially well in the polymer are obtained if they are present in the polymerization as the support for the active component of the catalyst.
It is already known from EP-B-0647657 that the polymerization of conjugated dienes, especially of butadiene, can be carried out in the gas phase, without the addition of solvents, if a catalyst system based on rare earth compounds and an organoaluminum compound on a particulate, inert, inorganic solid having a specific surface area greater than 10 m
2
/g (BET) and a pore volume of from 0.3 to 15 ml/g is used.
EP-B-0605001 claims the use of silica of a particular particle size as the support material and inert particulate materials to improve the flowability of tacky polymers.
EP-A-0442452 describes the use of inert particulate materials having particle diameters of from 0.01 to 10 &mgr;m to improve the flowability of tacky polymers in the case of polymerizations above the softening temperature of the said tacky polymers.
EP-A-0530709 describes the use of inert particulate materials having particle diameters of from 0.01 to 150 &mgr;m to improve the flowability of tacky polymers in the case of polymerizations above the softening temperature of the said tacky polymers.
In WO-88/02379 there is claimed the use of inert pulverulent inorganic materials in amounts of from 0.005 to 0.2 wt. %, based on the fluidized bed, to improve the flowability of polymers.
WO-96/04323 describes the use of inert particulate materials to improve the flowability of BR and IR in the case of polymerizations wherein the reactor temperature is below the dew point of one of the constituents of the circulating gas.
In EP-A-704464 there is described a resin particle having a tacky core and a non-tacky shell consisting of from 10 to 90% ethylene.
EP-A-570960 describes a resin particle having a tacky core and a non-tacky shell of inert particulate particles.
In all the processes described above, inert materials are used, with great importance being attached to the term inert.
U.S. Pat. No. 5,162,463, on the other hand, teaches that the agglomeration of the tacky particles in a fluidized bed can be avoided if an inert material coated with a polysiloxane coating is metered into the fluidized bed.
Finally, WO-97/08211 describes the addition of stabilizers in supported form.
It was completely unexpected to the person skilled in the art that, by using particulate materials coated with co-catalysts, it is possible very considerably to increase the activity of the catalyst system protected, inter alia, in EP-B-0647657 and consisting of
A) a rare earth alcoholate (I),
a rare earth carboxylate (II),
a complex compound of rare earths with diketones (III) and/or
an addition compound of the rare earth halides with an oxygen or nitrogen donor compound (IV), of the following formulae:
(RO)
3
M  (I)
(R—CO
2
)
3
M  (II)
 and
MX
3
.y donor  (IV),
B) an aluminum trialkyl, a dialkylaluminum hydride and/or an alumoxane of formulae (V) to (VII):
Al(H)
x
(R
1
)
3-x
  (V)
 wherein in the formulae
M represents a trivalent rare earth element having an atomic number from 57 to 71,
the radicals
R, which may be the same or different, represent an alkyl radical having C
1
-C
20
,
the radicals
R
1
, which may be the same or different, represent a C
1
-C
10
-alkyl radical,
X represents chlorine, bromine or iodine,
x represents 0 or 1,
y represents from 1 to 6, and
n represents from 1 to 50,
C) a further Lewis acid, and
D) a particulate, inorganic or organic solid having a specific surface area greater than 10 m
2
/g (BET), a particle size of from 10 to 1000 &mgr;m, preferably from 100 to 500 &mgr;m, and a pore volume of from 0.3 to 15 ml/g (where carbon black is used, additionally having, a DBP adsorption of more a than 30 ml/100 g).
DETAILED DESCRIPTION OF THE INVENTION
Suitable co-catalysts are all constituents having co-catalytic activity, especially the materials listed under B). Suitable support materials for these co-catalysts are all particulate materials, especially the materials listed under D).
If, on the other hand, a co-catalyst described under B) (e.g. aluminum alkyl) in liquid phase, whether it be in concentrated form or in dilute solution, is metered into the reaction chamber before and/or during the polymerization, the agitated reaction mass, for example in a stirred fixed bed or a fluidized bed, enters into an unstable state of fluidization as a result of spontaneous agglomeration and conglutination. The result is a drastically shortened useful life of the reactor. That is not the case if the supported co-catalyst solids according to the invention are metered into the gas-phase process and they are able to produce the desired action by intimate contact with the coated Nd catalyst described above or, inter alia, in EP-B-0647657. Furthermore, distribution within the reactor or the fluidized mass is markedly more homogeneous than is the case, for example, when a liquid co-catalyst material is injected into the reaction volume.
Also completely unexpected was the effect that the activity of the co-catalyst supported separately is markedly higher as compared with the same amount of co-catalyst supported together with the catalyst. The acceleration of the reaction, or increase in activity, achieved as a result of the co-catalyst's being supported separately is far greater than 30%, as compared with the co-catalyst supported together with the catalyst.
In component A), M represents a trivalent rare earth element having an atomic number in the periodic system of from 57 to 71. Preference is given to those compounds in which M represents lathanum, cerium, praseodymium or neodymium or a mixture of rare earth elements that contains at least one of the elements lanthanum, cerium, praseodymium or neodymium in an amount of at least 10 wt. %. Particular preference is given to compounds in which M represents lanthanum or neodymium or a mixture of rare earths that contains lanthanum or neodymium in an amount of at least 30 wt. %.
There may be mentioned as radicals R in formulae (I) to (IV) in particular straight-chained or branched alkyl radicals having from 1 to 20 carbon atoms, preferably from 1 to 15 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl, isopropyl, isobutyl, tert-butyl, 2-ethylhexyl, neopentyl, neooctyl, neodecyl, neododecyl.
Examples of alcoholates of component A) are: neodymium(III) n-propanolate, neodymium(III) n-butanolate, neodymium(III) n-decanolate, neodymium(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) n-decanolate, neodymium(III) 2-ethylhexanolate.
Suitable carboxylates of component A) are: lanthanum(III) propionate, lanthanum(III) diethylacetate, lanthanum(III) 2-ethylhexanoate, lant

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