Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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Process for the polymerisation of co_nju~ated diolefins (diene~ with rare
earth
catalysts in the presence of vinxl aromatic solvents
This invention relates to a process for the polymerisation of conjugated
diolefins in
the presence of rare earth catalysts and in the presence of aromatic vinyl
compounds.
It has long been known to polymerise conjugated dimes in the presence of a
solvent
and such polymerisation has been described, for example, by W. Hoffmann,
Rubber
Technology Handbook, Hanser Publishers (Carl Hanser Verlag), Munich, Vienna,
New York, 1989. Polybutadiene, for example, is accordingly now predominantly
produced by solution polymerisation using coordination catalysts of the
ZielgeriNatta type, for example based on titanium, cobalt, nickel and
neodymium
compounds, or in the presence of alkyllithium compounds. The solvent used in
each
case is highly dependent upon the type of catalyst used. Benzene or toluene as
well
as aliphatic or cycloaliphatic hydrocarbons are preferably used.
A disadvantage of currently performed polymerisation processes for the
production
of polydiolefins, such as for example BR, IR, SBR, is the elaborate working up
of
the polymer solution to isolate the polymers, for example by steam stripping
or
direct evaporation. A further disadvantage, especially if the polymerised
diolefins
are to be further processed as impact modifiers for plastics applications, is
that the
resultant polymeric diolefins must initially be redissolved in a new solvent,
for
example styrene, so that they may be further processed to yield, for example,
acrylonitrile/butadiene/styrene copolymer (ABS) or high impact polystyrene
(HIPS).
US 3299178 claims a catalyst system based on TiCl4/iodine/AI(iso-Bu)3 for the
polymerisation of butadiene in styrene to form homogeneous polybutadienes.
Harwart et al., Plaste rind Kautschuk, 24/8 (1977) 540, describe the
copolymerisation of butadiene and styrene using the same catalyst system and
the
suitability of the catalyst for the production of polystyrene.
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US 5096970 and EP 304088 describe a process for the production of
polybutadiene
in styrene using catalysts based on neodymium phosphonates, on organic
aluminium
compounds, such as di(isobutyl)aluminium hydride (DIBAH), and based on a Lewis
acid containing halogen, such as ethylaluminium sesquichloride, in which
butadiene
is reacted in styrene without further addition of inert solvents to yield a
1,4-cis-
polybutadiene. A disadvantage of this catalyst is that the resultant polymers
have a
very low content of 1,2 units of below 1%. This is disadvantageous because a
higher
1,2 content in polymers has a favourable effect on the bond between rubber and
the
polymer matrix, for example homo- or copolymers of vinyl aromatic compounds.
It is known from US 43 11 819 to use anionic initiators for the polymerisation
of
butadiene in styrene. According to the patent Examples, it was possible to
obtain an
SBR rubber suitable for use in HIPS either by terminating the polymerisation,
given
an initial concentration of butadiene in styrene of approx. 35 wt.%, at a
butadiene
monomer conversion of only approx. 25%, or by increasing the butadiene monomer
conversion to approx. 36% by an elevated butadiene concentration of approx.
~5 wt.%, such that the majority of the butadiene must in either case be
removed by
distillation before further use is made of the rubber solution in styrene for
impact
modification.
The disadvantage of the anionic initiators is that they result in the
formation of
butadiene/styrene copolymers (SBR) which, in relation to the butadiene units,
permit
only slight control of microstructure. It is not possible using anionic
initiators to
produce an SBR having an elevated cis content in which the 1,4-cis content is
above
40%. It is only possible to increase the proportion of 1,2 or 1,4-trans units
by adding
modifiers, wherein the 1,2 content above all results in an increase in the
glass
transition temperature of the polymer. This fact is primarily disadvantageous
because SBR is formed in this process in which, in comparison with
homopolymeric
polybutadiene (BR), a rising styrene content results in a further increase in
the glass
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transition temperature. However, if the rubber is to be used for impact
modification
of for example HIPS or ABS, an elevated glass transition temperature of the
rubber
has a disadvantageous effect on the low temperature toughness of the material,
such
that rubbers having low glass transition temperatures are preferred.
Kobayashi et al, J. Polym. Sci., Part A, Polym. Chem., 33 (1995) 2175 and 36
(1998)
241 have described a catalyst system consisting of halogenated rare earth
acetates,
such as for example Nd(OCOCC13)3 or Gd(OCOCF3)3, with tri(isobutyl)aluminium
and diethylaluminium chloride, which allows the copolymerisation of butadiene
and
styrene in the inert solvent hexane. Apart from the presence of inert
solvents, the
disadvantage of these catalysts is that, at a styrene incorporation of as
little as
approx. 5 mol.%, the catalyst activity falls to below 10 g of polymer/mmol. of
catalyst/h and that the 1,4-cis content of the polymer falls distinctly as the
styrene
content rises.
The advantage of SBR over pure BR for use in modifying plastics, for example
as
impact modifiers for ABS and HIPS, is that as the styrene content rises, the
refractive indices of the rubber and matrix come closer together, so improving
the
transparency of the modified plastics. On the other hand, the glass transition
temperature of the rubber increases with a rising styrene content, which then
has a
negative effect on the impact strength of the plastic.
The rubber solutions in styrene described in the stated patent publications
were used
for the production of HIPS by combining the rubber solutions in styrene with
free-
radical initiators once the unreacted diolefin had been removed.
On the other hand, the rubber is used in a matrix of acrylonitrile/styrene
copolymer
(SAN) in order to produce ABS. In contrast with the production of HIPS, the
SAN
matrix in ABS is incompatible with polystyrene. If homopolymers of the
solvent,
such as polystyrene, are formed as well as the rubber, when the diolefins are
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polymerised in vinyl aromatic solvents, the incompatibility of the SAN matrix
with
the polymerised vinyl aromatics results during the production of ABS in a
considerable impairment of the material properties of the ABS.
The object of the present invention was accordingly to provide a process for
the
polymerisation of conjugated diolefins in vinyl aromatic solvents, by means of
which copolymers are obtained in which the polymer composition may be varied
with regard to the content of vinyl aromatics and diolefins and with regard to
the
selectivity of the polymerised diolefins, i.e. for example content of double
bonds in
cis position and of 1,2 units with lateral vinyl groups, wherein the glass
transition
temperature of the poiymer is below -60°C, preferably below -
70°C.
The present invention accordingly provides a process for the copolymerisation
of
conjugated dimes with vinyl aromatic compounds, which process is characterised
in
that polymerisation of the conjugated dimes is performed in the presence of
catalysts consisting of
a) at least one rare earth metal compound,
b) at least one cyclopentadiene and
c) at least one organoaluminium compound
or consisting of
a) at least one rare earth metal compound and
c) at least one organoaluminium compound
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as well as in the presence of vinyl aromatic compounds at temperatures of -30
to
+100°C, wherein the molar ratio of components (a):(b):(c) is in the
range from
1:0.01-1.99:0.1-1000 or wherein the molar ratio of components (a):(c) is in
the range
from 1:0.1-1000, component (a) of the catalyst is used in quantities of 1
p.mol. to 10
mmol., relative to 100 g of the conjugated diolefins used, and the aromatic
vinyl
compound is used in quantities of 50 g to 2000 g, relative to 100 g of the
conjugated
diolefins used.
Conjugated diolefins (dimes) which may be used in the process according to the
invention are, for example 1,3-butadiene, 1,3-isoprene, 2,3-dimethylbutadiene,
2,4-
hexadiene, 1,3-pentadiene and/or 2-methyl-1,3-pentadiene.
It is, of course, also possible in the process according to the invention
additionally to
use, as well as the conjugated diolefins, further unsaturated compounds, such
as
ethylene, propene, 1-butene, 1-pentene, 1-hexene and/or 1-octene, preferably
ethylene and/or propene. which may be copolymerised with the stated diolefins.
The quantity of unsaturated compounds which may be copolymerised with the
conjugated diolefins is dependent upon the particular intended application of
the
desired copolymers and may readily be determined by appropriate preliminary
testing. It is conventionally 0.1 to 80 mol.%, preferably 0.1 to 50 mol.%,
particularly
preferably 0.1 to 30 mol.%, relative to the diolefin.
The molar ratio of components (a):(b):(c) in the catalyst used is preferably
in the
range from 1:0.1-1.9:3-500, particularly preferably 1:0.2-1.8:5-100. The molar
ratio
of component (a):(c) is preferably in the range from 1:3-500, in particular
1:5-100.
Rare earth metal compounds (component (a)) which may in particular be
considered
are those selected from among
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- a rare earth metal alkoxide,
- a rare earth metal phosphonate, phosphinate and/or phosphate,
- a rare earth metal carboxylate,
- a rare earth metal complex compound with diketones and/or
- an addition compound of rare earth metal halides with an oxygen or nitrogen
donor compound.
The above-stated rare earth metal compounds are described, for example, in EP
11 184.
1 S The rare earth metal compounds are in particular based on the elements
having the
atomic numbers 21, 39 and ~7 to 71. Preferably used rare earth metals are
lanthanum, praseodymium or neodymium or a mixture of rare earth metal elements
which contains at least 10 wt.% of at least one of the elements lanthanum,
praseodymium or neodymium. Very particularly preferably used rare earth metals
are lanthanum or neodymium, which may in turn be blended with other rare earth
metals. The proportion of lanthanum and/or neodymium in such a mixture is
particularly preferably at least 30 wt.%.
Rare earth metal alkoxides, phosphonates, phosphinates and carboxylates or
rare
earth metal complex compounds with diketones which may in particular be
considered are those in which the organic group present in the compounds in
particular contains linear or branched alkyl residues having 1 to 20 carbon
atoms,
preferably 1 to 1 S carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-
pentyl,
isopropyl, isobutyl, tert.-butyl, 2-ethylhexyl, neopentyl, neooctyl, neodecyl
or
neododecyl.
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Rare earth alkoxides which may, for example, be mentioned are:
neodymium(III) n-propanolate, neodymium(III) n-butanolate, neodymium(III)
n-decanolate, neodymium(III) isopropanolate, neodymium(III) 2-ethylhexanolate,
S praseodymium(III) n-propanolate, praseodymium(III) n-butanolate, praseodym
ium(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 and lanthanum(III)
2-
ethylhexanolate, preferably neodymium(III) n-butanolate, neodymium(III) n-
-decanolate and neodymium(III) 2-ethylhexanolate.
Rare earth phosphonates, phosphinates and phosphates which may, for example be
mentioned are: neodymium(III) dibutylphosphonate, neodymium(III) dipentylphos-
phonate, neodymium(III) dihexylphosphonate, neodymium(III) diheptyl-
phosphonate, neodymium(III) dioctylphosphonate, neodymium(III)
dinonylphosphonate, neodymium(III) didodecylphosphonate, neodymium(III)
dibutylphosphinate, neodymium(III) dipentylphosphinate, neodymium(III)
dihexylphosphinate, neodymium(III) diheptylphosphinate, neodymium(III)
dioctylphosphinate, neodymium(III) dinonylphosphinate, neodymium(III)
didodecylphosphinate and neodymium(III) phosphate, preferably neodymium(III)
dioctylphosphonate and neodymium(III) dioctylphosphinate.
Suitable rare earth metal carboxylates are:
lanthanum(III) propionate, lanthanum(III) diethylacetate, lanthanum(III) 2-
ethyl
hexanoate, 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, praseo
dymium(III) oleate, praseodymium(III) versatate, praseodymium(III)
naphthenate,
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neodymium(III) propionate, neodymium(III) diethylacetate, neodymium(III) 2-
ethyl-
hexanoate, neodymium(III) stearate, neodymium(III) benzoate, neodymium(III)
cyclohexanecarboxylate, neodymium(III) oleate, neodymium(III) versatate and
neodymium(III) naphthenate, preferably neodymium(III) 2-ethylhexanoate, neodym-
ium(III) versatate and neodymium(III) naphthenate. Neodymium versatate is
particularly preferred.
Rare earth metal complex compounds with diketones which may be mentioned are:
lanthanum(III) acetylacetonate, praseodymium(III) acetylacetonate and neodym-
ium(III) acetylacetonate, preferably neodymium(III) acetylacetonate.
Addition compounds of rare earth metal halides with an oxygen or nitrogen
donor
compound which may, for example, be mentioned are:
lanthanum(III) chloride with tributyl phosphate, lanthanum(III) chloride with
tetra-
hydrofuran, lanthanum(III) chloride with isopropanol, lanthanum(III) chloride
with
pyridine, lanthanum(III) chloride with 2-ethylhexanol, lanthanum(III) chloride
with
ethanol, praseodymium(III) chloride with tributyl phosphate, praseodymium(III)
chloride with tetrahydrofuran, praseodymium(III) chloride with isopropanol,
praseo-
dymium(III) chloride with pyridine, praseodymium(III) chloride with 2-ethyl-
hexanol, praseodymium(III) chloride with ethanol, neodymium(III) chloride with
tributyl phosphate, neodymium(III) chloride with tetrahydrofuran,
neodymium(III)
chloride with isopropanol, neodymium(III) chloride with pyridine,
neodymium(III)
chloride with 2-ethylhexanol, neodymium(III) chloride with ethanol,
lanthanum(III)
bromide with tributyl phosphate, lanthanum(III) bromide with tetrahydrofuran,
lanthanum(III) bromide with isopropanol, lanthanum(III) bromide with pyridine,
lanthanum(III) bromide with 2-ethylhexanol, lanthanum(III) bromide with
ethanol,
praseodymium(III) bromide with tributyl phosphate, praseodymium(III) bromide
with tetrahydrofuran, praseodymium(III) bromide with isopropanol,
praseodymium(III) bromide with pyridine, praseodymium(III) bromide with 2-
ethylhexanol, praseodymium(III) bromide with ethanol, neodymium(III) bromide
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with tributyl phosphate, neodymium(III) bromide with tetrahydrofuran,
neodymium(III) bromide with isopropanol, neodymium(III) bromide with pyridine,
neodymium(III) bromide with 2-ethylhexanol and neodymium(III) bromide with
ethanol, preferably lanthanum(III) chloride with tributyl phosphate,
lanthanum(III)
chloride with pyridine, lanthanum(III) chloride with 2-ethylhexanol,
praseodymium(III) chloride with tributyl phosphate, praseodymium(III) chloride
with 2-ethylhexanol, neodymium(III) chloride with tributyl phosphate,
neodymium(III) chloride with tetrahydrofuran, neodymium(III) chloride with 2-
ethylhexanol, neodymium(III) chloride with pyridine, neodymium(III) chloride
with
2-ethylhexanol and neodymium(III) chloride with ethanol.
Very particularly preferably used rare earth metal compounds are neodymium
versatate, neodymium octanoate and/or neodymium naphthenate.
The above-stated rare earth metal compounds may be used both individually and
mixed together. The most favourable mixing ratio may readily be determined by
appropriate preliminary testing.
The cyclopentadienes (component (b)) used are compounds of the formulae (I),
(II)
or (III)
H R: H R~ R' R~ H R~ R:
R= R= \ Ra
Ry ~ II R ~ ~ ~ ~ R
R'
R~ R3 R~ ~. Rs
75 R_ Rs Ra R
(I) (II) (III)
in which R' to R9 are identical or different or are optionally joined together
or are
fused on the cyclopentadiene of the formula (I), (II) or (III) and may denote
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hydrogen, a C~-C3o alkyl group, a C~-C,o aryl group, a C7-C4o alkylaryl group
and a
C,-Coo silyl group, wherein the alkyl groups may be either saturated or mono-
or
polyunsaturated and may contain heteroatoms such as oxygen, nitrogen or
halides.
The residues may in particular denote hydrogen, methyl, ethyl, n-propyl,
isopropyl,
n-butyl, isobutyl, tert.-butyl, phenyl, methylphenyl, cyclohexyl, benzyl,
trimethylsilyl or trifluoromethyi.
Examples of cyclopentadienes are unsubstituted cyclopentadiene,
methylcyclopenta-
dime, ethylcyclopentadiene, n-butylcyclopentadiene, tert.-
butylcyclopentadiene,
vinylcyclopentadiene, benzylcyclopentadiene, phenylcyclopentadiene,
trimethylsilylcyclopentadiene, 2-methoxyethylcyclopentadiene, 1,2-
dimethylcyclopentadiene, 1,3-dimethylcyclopentadiene,
trimethylcyclopentadiene,
tetramethylcyclopentadiene, tetraphenylcyclopentadiene,
tetrabenzylcyclopentadiene, pentamethylcycylopentadiene,
pentabenzylcyclopentadiene, ethyltetramethylcyclopentadiene, trifluoromethyl-
tetramethylcyclopentadiene, indene, 2-methylindenyl, trimethylindene,
hexamethyl-
indene, heptamethylindene, 2-methyl-4-phenyiindenyl, fluorene or
methylfluorene.
The cyclopentadienes may also be used individually or mixed together.
Organoaluminium compounds (component (c)) which may in particular be
considered are alumoxanes and/or aluminiumorganyl compounds.
The alumoxanes used are aluminiumloxygen compounds which, as is known to the
person skilled in the art, are obtained by bringing organoalumium compounds
into
contact with condensing components, such as for example water, and which
constitute acyclic or cyclic compounds of the formula (-AI(R)O-)~, wherein R
may
be identical or different and denotes a linear or branched alkyl group having
1 to 10
carbon atoms, which may additionally contain heteroatoms, such as for example
oxygen or nitrogen. R in particular denotes methyl, ethyl, n-propyl,
isopropyl, n-
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butyl, isobutyl, tert.-butyl, n-octyl or isooctyl, particularly preferably
methyl, ethyl
or isobutyl. Examples of alumoxanes which may be mentioned are:
methylalumoxane, ethylalumoxane and isobutylalumoxane, preferably
methylalumoxane and isobutylalumoxane.
The aluminiumorganyl compounds used are compounds of the formula A1R3_aXa,
wherein
R may be identical or different and may denote a C,-Coo aryl group and a C~-
C4o alkylaryl group, wherein the alkyl groups may be either saturated or
monounsaturated and may contain heteroatoms, such as oxygen or nitrogen,
X denotes a hydrogen, an alkoxide, phenolate or amide and
1 S d means a number from 0 to 2.
Organoaluminium compounds of the formula A1R3_aXa which may in particular be
used are: trimethylaluminium, triethylaluminium, tri-n-propylaluminium,
triiisopropylaluminium, tri-n-butylaluminium, triisobutylaluminium, tripentyl-
aluminium, trihexylaluminium, tricyclohexylaluminium, trioctylaluminium,
diethyl-
aluminium hydride, di-n-butylaluminium hydride, diisobutylaluminium hydride,
diethylaluminium butanolate, diethylaluminiummethylidene(dimethyl)amine and
diethylaluminiummethylidene(methyl) ether, preferably trimethylaluminium,
triethylaluminium, triisobutylaluminium and diisobutylaluminium hydride.
The organoaluminium compounds may again be used individually or mixed
together.
A further component (d) may also be added to the catalyst components (a) to
(c).
This component (d) may be a conjugated dime, which is for example the same
dime
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which is subsequently to be polymerised with the catalyst. Butadiene and/or
isoprene
are preferably used.
If component (d) is added to the catalyst, the quantity of (d) is preferably 1
to 1000
mol. relative to 1 mol. of component (a), particularly preferably 1 to 100
mol.. Very
particularly preferably, 1-50 mol. of (d) are used relative to 1 mol. of
component (a).
In the process according to the invention, the catalysts are used in
quantities of
preferably 10 ~mol. to S mmol. of component (a), particularly preferably of 20
~mol. to 1 mmol. of component (a), relative to 100 g of the monomers.
It is, of course, also possible to use the catalysts in any desired mixture
with each
other.
The process according to the invention is performed in the presence of
aromatic
vinyl compounds, in particular in the presence of styrene, a.-methylstyrene,
a-methylstyrene dimer, p-methylstyrene, divinylbenzene and/or other
alkylstyrenes
having 2 to 6 C atoms in the alkyl residue, such as ethylbenzene.
The polymerisation according to the invention is very particularly preferably
performed in the presence of styrene, a-methylstyrene, a-methylstyrene dimer
and/or p-methylstyrene as solvent.
The solvents may be used individually or as a mixture; the most favourable
mixing
ratio may readily be determined by appropriate preliminary testing.
The quantity of aromatic vinyl compounds used is preferably 30 to 1000 g, very
particularly preferably SO to 500 g, relative to 100 g of monomers used.
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The process according to the invention is preferably performed at temperatures
of -
20 to 90°C, particularly preferably at temperatures of 20 to
80°C.
The process according to the invention may be performed without pressure or at
elevated pressure (0.1 to 12 bar).
The process according to the invention may be implemented continuously or
discontinuously, preferably with continuous operation.
The solvent used in the process according to the invention need not be removed
by
distillation, but may instead remain in the reaction mixture. In this manner,
it is
possible, for example when styrene is used as the solvent, subsequently to
perform a
second polymerisation for the styrene, wherein an elastomeric polydiene in a
polystyrene matrix is obtained. Similarly, acrylonitrile may be added to the
polydiene solution in styrene before the second polymerisation is performed.
In this
manner, ABS is obtained. Such products are of particular interest as impact-
modified thermoplastics.
It is, of course, also possible to remove a proportion of the solvent used
and/or of the
unreacted monomers after polymerisation, preferably by distillation optionally
under
reduced pressure, in order to achieve the desired polymer concentration.
Further components, for example unsaturated organic compounds, such as
acrylonitrile, methyl methacrylate, malefic anhydride or maleimides, which may
be
copolymerised with the vinyl aromatic solvent, and/or usual aliphatic or
aromatic
solvents, such as benzene, toluene, dimethylbenzene, ethylbenzene, hexane,
heptane
or octane, and/or polar solvents, such as ketones, ethers or esters, which are
conventionally used as solvents and/or diluents for the polymerisation of the
vinyl
aromatic solvent, may furthermore be added to the polymer solution before or
during
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the subsequent polymerisation of the solvent, which may be initiated in a
known
manner, for example by free-radical or thermal means.
As has already been mentioned above, the process according to the invention is
distinguished by particular economic viability and good environmental
compatibility, as the solvent used may be polymerised in a subsequent stage,
wherein the polymer present in the solvent serves to modify thermoplastics
(for
example to increase impact strength).
In the process according to the invention, the composition and thus the
properties of
the resultant polymers may be varied very widely.
For example, by varying the substituents of the cyclopentadiene used, it is
possible
to influence the microstructure of the resultant copolymers; for example the
content
of 1,2 units, i.e. of lateral double bonds in the polymer chain, and the
content of
double bonds in 1,4-cis position in the polymer chain. The nature of the
substitution
of the cyclopentadiene used furthermore influences copolymerisation
parameters, in
particular with regard to the diolefins and vinyl aromatic solvents used. For
example,
the content of vinyl aromatics in the resultant polymer may be influenced in
this
manner by varying the catalyst composition.
It is furthermore possible to influence polymer composition by varying the
reaction
conditions, such as by varying the ratio of diolefins and vinyl aromatic
solvents
used, the catalyst concentration, the reaction temperature and reaction time.
Another advantage of the process according to the invention is that, in the
case of
direct polymerisation in styrene, it is also possible to produce and
straightforwardly
further process low molecular weight polymers of such a low molecular weight
that,
as solids having elevated cold flow or elevated tackiness, they could be
processed
and stored only with difficulty.
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The advantage of low molecular weight polymers is that, even at an elevated
polymer content, the solution viscosity remains as low as desired and the
solutions
may consequently readily be conveyed and processed.
Using the process according to the invention, it is possible by polymerising
diolefins
in vinyl aromatic solvents to obtain copolymers of diolefins and vinyl
aromatics,
which, in contrast with anionic initiators, have an elevated content of 1,4-
cis double
bonds relative to the diolefin content and which furthermore allow simple
control of
microstructure, i.e. the content of lateral 1,2 and 1,4-cis units, polymer
composition
and molecular weight while elevated catalyst activity and elevated conversion
of the
diolefins used are simultaneously achieved.
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Examples
The polymerisation reactions were performed in the absence of air and moisture
under argon. The isolation of the polymers from the solution in styrene
described in
individual Examples was performed solely for the purpose of characterising the
polymers obtained. The polymers may, of course, also be stored and
appropriately
further processed in the solution in styrene without being isolated.
The styrene used as the solvent for the diolefin polymerisations was stirred
under
argon for 24 hours over CaHZ at 25°C and distilled at 25°C under
reduced pressure
(Examples 1 to 16). In order to demonstrate that polymerisation is also
possible with
stabilised styrene, in some of the Examples the styrene was dried for 2 days
over
molecular sieve 4A (Baylith) and the polymerisation performed in the presence
of
the stabiliser (bis(tert.-butyl)pyrocatechol, 15 ppm) (Examples 17-19).
The styrene content in the polymer is determined by ' H-NMR spectroscopy,
polybutadiene selectivity (1,4-cis. 1,=1-trans and 1,2 content) is determined
by IR
spectroscopy, the solution viscosity in a ~ wt.% solution of the polymer in
styrene is
determined by an Ubbelohde viscosimeter at 25°C, the glass transition
temperature
To is determined by DSC and the water content is determined by Carl-Fischer
J
titration.
Examples 1 to 5
Catal,~geing
7.2 g of butadiene, 0.57 ml of indene and 88.6 ml of a 10% solution of
methylalumoxane in toluene (MAO) were added at 25°C through a septum to
20 ml
of a 0.245 molar solution of neodymium(III) versatate (NDV) in hexane in a 100
ml
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Schlenk tube, maintained at 50°C with stirnng for 2 hours and used
for the
polymerisation.
Polymerisation
Polymerisation proceeded in a 0.5 litre flask, which was provided with a crown
cork
with an integral septum. The stated quantity of liquid butadiene was added to
the
initially introduced styrene under argon through a cannula and the stated
quantities
of a 1 molar solution of tri(isobutyl)aluminium in toluene (TIBA) as scavenger
and
the aged catalyst solution were then added with a syringe. The temperature
during
the polymerisation was established by a water bath. After the stated reaction
time,
the polymer was isolated by precipitating the polymer solution in methanol/BKF
(BKF = bis[(3-hydroxy)(2,4-di-tert.-butyl)(6-methyl)phenyl]methane) and dried
for
one day in a vacuum drying cabinet at 60°C. Table 1 shows the batch
sizes, reaction
conditions and the properties of the polymers obtained.
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Table 1: Examples 1 to 5
Example 1 2 3 4 5
Catalyst solution in ml 4.91 4.91 2.46 2.21 3.68
NDV in mmol. 0.2 0.2 0.1 0.09 0.15
Polymerisation
Styrene in ml 40 75 75 100 100
1,3-butadiene in g 10.7 21.0 19.5 15.6 25.6
TIBA (1 molar) in ml - - - 0.9 1.5
Temperature in C 40 50 40 50 50
Reaction time in h 3.2 1.5 3.5 3.5 3.5
Polymer
Yield in g 6.7 20.7 12.8 20.2 38.8
Styrene content in mol.% 5.3 18.9 10.4 29.8 37.9
Butadiene content in mol.% 94.7 81.1 89.6 70.2 62.1
cis in % 63 55 58 53 51
traps in % 32 41 35 38 41
1,2 in % 5 4 7 10 8
rl (5% in styrene) in mPa~s 5.95 nd nd nd nd
T~ in C -97.5 nd -92 nd nd
nd = not determined.
Example 6
Catalyst aageing
Catalyst ageing proceeded in a similar manner to Examples 1 to 5.
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Polymerisation
Polymerisation proceeded in a 6 litre glass jar equipped with an anchor
stirrer, a
reflux condenser connected to a cryostat set at a temperature of -30°C,
a jacket
connected to a thermostat, an internal thermometer, a septum and an argon
connection. 292 g of liquid butadiene were added at 25°C under argon to
1050 ml of
styrene and 68.8 ml of aged catalyst solution were then added. Polymerisation
was
performed at 50°C and terminated after 3 hours by adding 20 ml of
acetone with 2 g
of BKF.
The solids content of the polymer solution was 34%. The polymer is of the
following composition: 29.0 mol.% styrene, 71.0 mol.% butadiene (with 54% 1,4-
cis, 41% 1,4-trans, 5% 1,2 units), viscosity (5 wt.% in styrene) is 15.3
mPa~s, the
glass transition temperature is -86°C.
Examples 7-10
Catalyst ageing
7.1 g of butadiene, 0.80 ml of pentamethylcyclopentadiene and 147 ml of a 10%
solution of methylalumoxane in toluene (MAO) were added at 25°C through
a
septum to 20 ml of a 0.245 molar solution of neodymium(III) versatate (NDV) in
hexane in a 100 ml Schlenk tube, maintained at 50°C with stirring for 2
hours and
used for the polymerisation.
Polvmerisation
Polymerisation was performed as in Examples 1-5, wherein different aluminium
compounds were used as the scavenger. Table 2 shows the batch sizes, reaction
conditions and the properties of the polymers obtained.
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Table 2: Examples 7 to 10
Example 7 8 9 10
Catalyst solution in ml 2.19 3.28 5.47 7.29
NDV in mmol. 0.06 0.09 0.15 0.2
Polymerisation
Styrene in ml 100 100 100 75
1,3-butadiene in g 10.2 15.4 25.8 21.8
TIBA (1 molar) in ml 0.6 0.9 1.5 -
TMA (1 molar) in ml - - - -
Temperature in C ~0 50 50 50
Reaction time in h 3.5 3.5 3.5 2
Pol,~%mer
Yield in g 9.1 19.3 42.2 24.5
Styrene content in mol.% 22.6 29.0 44.8 20.4
Butadiene content in mol.%77.4 71.0 55.2 79.6
cis in % 65 58 53 47
trans in % 27 34 39 45
1,2 in % 8 8 8 9
rl (5% in styrene) in mPa~s12.6 15.2 15.6 nd
T" in C -76.5nd -78
Examples 11-16
Catalyst ageing
7.0 g of butadiene. 0.80 of a
ml of pentamethylcyclopentadiene 10%
and 88 ml
solution of methylalumoxanein toluene (MAO) addedat 25C through
were a
septum to 20 ml of a 0.245 um(III)versatate(NDV)
molar solution of neodymi in
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hexane in a 100 ml Schlenk tube, maintained at 50°C with stirring for 2
hours and
used for the polymerisation.
Polymerisation
Polymerisation proceeded in a 6 litre glass jar equipped with an anchor
stirrer, a
reflux condenser connected to a cryostat set at a temperature of -30°C,
a jacket
connected to a thermostat, an internal thermometer, a septum and an argon
connection. Polymerisation proceeded in a similar manner to Example 8. Table 3
shows the batch sizes, polymerisation conditions and results.
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Ta le 3: Examples 11 to 16
Example 11 12 13 14 15 16
Catalyst solution 24.4 18.8 18.8 24.4 24.4 18.8
in ml
NDV in mmol. 1 0.77 0.77 1 1 0.77
Polymerisation
Styrene in ml 1300 2000 2000 3000 1300 2000
1,3-butadiene in g 207 317 305 405 200 301
MAO (1.66 molar) in 12 4.8 - - - -
ml
TMA (1 molar) in ml - - 7.7 10 - -
TIBA (1 molar) in - - - - 20 7.7
ml
Temperature in C 47 50 50 50 50 50
Reaction time in h 3 5 5 5 3 3.8
Pol.
Yield in g 278 377 392 461 289 358
.
Styrene content in 39.8 24.2 24.9 23.4 37.9 53.6
mol.%
Butadiene content 60.2 75.8 75.1 76.6 62.1 46.4
in mol.,%
cis in % 43 58 47 50 58 66
trans in ,% 48 33 44 41 34 23
1,2 in % 9 9 9 9 8 10
rl (5% in styrene) 20 32 44 37 10 26
in mPa~s
T~ in C -76.5 nd nd nd -77.0 nd
Examples 17-19
Catalyst ageing
5.3 g of butadiene, 1.88 ml of pentamethylcyclopentadiene and 217 ml of a 10%
solution of methylalumoxane in toluene (MAO) were added at 25°C through
a
septum to 38.4 ml of a 0.3125 molar solution of neodymium(III) versatate (NDV)
in
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hexane in a 300 ml Schlenk tube, maintained at 50°C with stirnng for 2
hours and
used for the polymerisation.
Polymerisation
Polymerisation proceeded in a 40 litre steel reactor with an anchor stirrer
(50 rpm).
A solution of trimethylaluminium in hexane as scavenger was added at room
temperature to a solution of butadiene in styrene, the reaction solution
adjusted to a
temperature of 50°C within 45 minutes and combined with the
corresponding
quantity of catalyst solution. The reaction temperature was maintained at
SO°C
during the polymerisation. On completion of the reaction time, the polymer
solution
was transferred within 15 minutes into a second reactor (80 litre reactor,
anchor
stirrer, SO rpm) and polymerisation shortstopped by adding 3410 g of butanone
with
7.8 g of Vulkanox KB and 25.5 g of Irgafos TNPP. Unreacted butadiene was
removed by reducing the pressure within the reactor at 50°C to 200 mbar
within 1
hour and to 100 mbar within 2 hours.
Table 4 shows the batch sizes, reaction conditions and the properties of the
polymers
obtained.
ii
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T le 4: Examples 17 to 19
Example 17 18 19
Catalyst solution in ml 166 161 161
NDV in mmol. 7.5 7.3 7.3
Polymerisation
Styrene in g 18070 16890 17154
Water content in ppm 83 30 37
1,3-butadiene in g 3003 3700 3703
TMA (2 molar) in ml 17 5.6 7
Temperature in C 50 50 50
Reaction time in h 4.5 3.25 3
Po_ lymer
Solids content in wt.,% 16.31 16.29 15.51
Styrene content in mol.% 25.8 15.6 13.6
Butadiene content in mol.% 74.2 84.4 86.4
cis in % ~7 62 64
trans in % 3~ 29 26
1,2 in % 8 9 10
rl (~% in styrene) in mPa~s46 59 78
T~ in C -67 -74 -77
Mn in kg/mol. 242 nd nd
M~,, in kg/mol. 332 nd nd
Examples 20 to 25
S
Catal.~geing
7.2 g of butadiene, 0.57 ml of indene and 88.6 ml of a 10% solution of
methylalumoxane in toluene (MAO) were added at 25°C through a septum to
20 ml
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of a 0.245 molar solution of neodymium(III) versatate (NDV) in hexane in a 100
ml
Schlenk tube, maintained at SO°C with stirnng for 2 hours and used
for the
polymerisation.
Polymerisation
Polymerisation proceeded in a 0.5 litre flask, which was provided with a crown
cork
with an integral septum. The stated quantity of liquid butadiene was added to
the
initially introduced styrene and a further component (a-methylstyrene,
divinylbenzene or isoprene) under argon through a cannula and the stated
quantities
of the aged catalyst solution were then added with a syringe. The temperature
during
the polymerisation was established by a water bath. After the stated reaction
time,
the polymer was isolated by precipitating the polymer solution in methanolBKF
and
dried for one day in a vacuum drying cabinet at 60°C. Table 5 shows the
batch sizes,
reaction conditions and the properties of the polymers obtained.
i
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Table 5: Examples 20 to 25
Example 20 21 22 23 24 25
Catalyst solution 1.23 1.23 1.23 1.23 1.23 1.23
in ml
NDV in mmol. 0.05 0.05 0.05 0.05 0.05 0.05
Polymerisation
Styrene in ml 100 100 100 100 100 100
1,3-butadiene in g 21.1 22.8 22.3 23.6 25.1 21.5
a-Methylstyrene 5 20
Divinylbenzene 5 20
Isoprene in ml 5 20
Temperature in C 50 50 50 50 50 50
Reaction time in h 2.5 2.5 2.5 2.5 0.5 0.5
Po- lyer
Yield in g 15.2 10.5 9.1 9.6 12.3 23.6
Styrene content in nd 11 nd 10 nd 16
moi..!
Butadiene content nd 89 nd 90 nd 84
in mol.%
cis in % nd 79 nd 77 nd nd
trans in % nd 15 nd 18 nd nd
". ." , ~ , ~ , ,
