Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~3~ 3
~ o.Z. 0050/39143
Preparation of homopolymers and copolymers of propene
using_a Ziegler-Natta catalyst system
The present ;nvention relates to a process for
the preparation of homopolymers of propene and copolymers
of propene w;th m;nor amounts of other C~-C12-~-mono-
olefins, in particular Cz-C6-~-monoolefins, by polymeri-
zation, in particular by dry-phase polymerization, of the
monomer or monomers at from 20 to 160C, in particular
from S0 to 120C, and under from 1 to 100, in particular
from 20 to 70, bar using a Ziegler-Natta catalyst system
consisting of
t1) a titanium component which is based on a f;nely div;-
ded, shape-imparting silica gel and, in addit;on to
titanium, contains magnesium, chlorine and a benzene-
carboxylic ac;d derivative,5 (2) an aluminum component of the formula
AlR3,
where R is alkyL of not more than 8, in particular
not more than ~, carbon atoms,
and0 (3) a silane component of the for~ula
R1 SilOR2)4_n,
where R1 is a saturated al;ph~tic and/or aromatic
hydrocarbon radical of not more than 16, preferably
ZS not more than 10, carbon atoms, R2 is alkyl of not
~ore than 15, preferabLy not more than 8, in particu-
lar not more than 4, carbon atoms and n is from û to
3, preferably from 0 to 2, in particular 1,
~ith ~he pro~isos that the ato~ic ratio of titanium from0 the titanium component tl) to aluminum -from the aluminum
conponent (2l is from l : 10 to 1 : 800, in particular
from 1 : 20 to 1 : 200~ and the molar ratio of aluminum
component t2) to silane component t3) is from 1 : 0.03
to 1 : 0.8, ;n particular from 1 : 0.05 to 1 : O.S.
Polymerization processes of this type are known;
their special feature compared with other similar processes
- 2 - O.Z. 0050/39143
is the specific embodiment of the catalyst system, and
the processes disclosed in European Laid-Open Applica-
tions 0,014,523, 0,045,977, 0,171,200 and 0,195,497 and
in ~ritish Patencs 2,101,609 and 2,10i,611 may be
mentioned as prototypes for the present case.
The specific embodiments of the catalyst systems
are employed ;n order to açhieve certain purposes, such
as the following:
The catalyst system should be easy to prepare
and give a high yield of polymer which must contain a
very large isotactic fraction. The catalyst system
should moreover produce polymers having spec;al morpho-
logical properties, for example uniform particle size
and/or a smaller fraction of very ~ine particles and/or
a high bulk density~ In addition to these parameters
which are important for controlling the polymerization
systems, ~ork;ng up the polymers and/or processing them,
a lo~ halogen content in the polymer is also important,
particularly with regard to corrosion problems; this can
ZO be achieved by increasing the polymer yield and/or by
means of a catalyst system which contains very little
halogen.
In the prior art, some of these purposes can be
achieved only by very expensive methods or if other
purposes are neglected:
For example, European Laid-Open Application
0,045,977 descr;bes a catalyst system consisting of ac-
tive MgClz, T;Cl4 and a phthal;c acid derivative. With
sil;c3 gel as the shape-impart;ng carr;er, the produc-
tivity of the catalyst system is, however~ no longersatisfactory; furthermore, the chlor;ne content of the
polymers is comparatively high.
European Laid-Open Applications 0,014,523 and
0,171,200 and ~ritish Patents 2,101,609 and 2,101,611
describe catalyst systems whose t;tanium component is
obtained by treating a solid, inorganic oxide ~ith an
organ;c magnes;um compound, a Le~is base and titanium
~3~ 83
_ 3 _ o.z. 0050~39143
tetrachloride, it be;ng necessary in addition to use a
halogenating agent ~hich is not titanium tetrachloride
and/or an organic compound of the metals boron, aluminum~
silicon or tin or a boron trihalide or a halogen-containing
alcohol. In spite of an expensive and tedious preparation
procedure, the productivity of the corresponding catalyst
system is unsatisfactory.
European Laid-Open Application 0,195,497 describes
a catalyst system whose titanium component is obtained
by treating SiO2 with an organic Mg compound, an alcohol,
a Lewis base and TiCl4. In the case of this catalyst sys-
tem too, the productivity ;s low.
The known processes are thus unsatisfactory, par-
ticularly with regard to good productivity and a low
chlorine content in the polymers, in combination with
high isotacticity and good morphology.
It is an object of the present invention to pro-
vide a titanium component which, compared with the prior
art processes, has good productivity and is also capable
of giving polymers hav;ng a low chlorine content, high
isotacticity and good morphology.
~ e have found that this object is achieved by a
catalyst system which contains a titanium component (1)
prepared in a particuLar manner from (I) a special car-
rier obtained in a defined manner from (Ia) a certa;n
finely divided silica gel, (Ib) a certain organomagnesium
compound and (Ic) a certain gaseous chlorinating agent,
and (II) a certain alkanol, (III) titanium tetrachloride
and (IV) a specially selected phthalic acid derivative.
The present invention accordingly relates to a
process for the preparation of homopolymers of propene
and co~olymers of propene ~ith m;nor amounts of other
C2-C12-~-mcnool~fins, in particular C2-C6-r~-mono-
olefins, by polymerization, in particular by dry-phase
polymerization of the monomer or monomers at from 20 to
160C, in particular fro~ 50 to 120C, uncJer from 1 to
100~ in particular from 20 ~o 70, bar using a Ziegler-
13~1 !33
- 4 - o.z. OOS0/39143
Natta catalyst system consisting of
(1) a titanium component which is based on a finely divi-
ded, shape-imparting silica gel and~ in addition to
titanium, contains magnesium, chlorine and a benzene-
carboxylic acid derivative,
~2) an aluminum component of the formula
AlR3,
where R is alkyl of not more than 8, in particular
not more than 4, carbon atoms,
and
(3) a silane component of the formula
Rl si l oR2 ) 4-n
where R1 is a saturated aliphatic and/or aromatic
hydrocarbon radical of not more than 16, preferably
not msre than 10, carbon atoms, R2 is alkyl of not
more than 15, preferably not more than 8, in particu-
lar not more than 4~ carbon atoms and n is from 0 to
3, preferably from 0 to 2, in particular 1,
with the prov;sos that the atomic ratio of titanium from
the titanium component (1) to aluminum from the aluminum
component (2) is from 1 : 10 to 1 : 800, in particular
from 1 : 20 to 1 : 200, and the molar ratio of aluminum
component (2) to silane component (3) is from 1 : 0.03
to 1 : 0.8, in particular from 1 : 0.05 to 1 : 0.5.
In the novel process, the titanium component (1)
used is one which is obtained by a method in ~hich first
(1.1) in a first stage (1), a carr;er is prepared from
(Ia) a finely divided silica gel uhich has a particle
diameter of from 1 to 1,000 ~m, in particular from 10
to 4Q0 ~m, a pore volume of from 0.3 to 3, in particular
from 1 to 2.5, c~3/g and a surface area of from 100 to
1,000, in particular from 200 to 400, m2/g and is of the
formula SiO2 . a Al203, where a is from 0 to 2, in par-
ticular from 0 to 0.5, (Ib) an organomagnesium compound
of the formula MgR3R4, where R3 and R4 are each C2-
C10-a~kyl, preferably C4 C8-alkyl, and (Ic) a gaseous
13()~3
_ 5 _ o z. 0050/39143
chlorinating agent of the formula ClZ, where Z is Cl or
H, preferably H, by a method in which first (1~1.1) in a~
first substage, in a liquid inert hydrocarbon, in par-
ticular an alkane, with constant thorough mixing at room
temperature, the finely divided silica gel (Ia) and the
organomagnesium compound (Ib) are combined, from 1 to 10,
in particular from 1.5 to 4, molar parts of the organo-
magnesium compound (Ib) being used per 10 molar parts of
silicon of the silica gel (Ia), and the substances com-
10 bined are kept at from 20 to 140C, in particular from
60 to 40C~ for from 0.5 to 5, in particular from 1 to 2,
hours, then
(1.1.2) in a second substage, with constant thorough mix-
ing at from -20 to ~80C, in particular 0 to ~20C, the
gaseous chlorinating agent (Ic) is passed into the pro-
duct obtained from the first substage, from Z to 40, in
particular from 10 to 20, molar parts of the chlorinat;ng
agent (Ic) being used per molar part of the organomagnes-
ium compound (Ib), the entire mix~ure is left at a te~-
perature in the stated range for from 0.5 to 5 hours~ inparticular fro0 0.5 to 1 hour, and the resulting solid-
phase product, ie. the carrier (I), is isolated with re-
moval of the liquid phase, thereatter
(1.2) ;n a second stage, a solid-phase intermediate is
prepared from (I) the carrier obtained in the first stage,
(II) a Cz-C6-alkanol, in particular ethano(, (III) titan-
iu~ tetrachloride and (IV) a phthalic acid derivati~e of
the for~ula
, ~c~x
co-r
.
~here X and Y together form oxygen or X and r are each
chlorine or C1-C10-alkoxy, preferably Cz-C8-alko~y, in
particular butoxy, by a method in which first
(1.2~1) in a first substage, in a liquid inert hydrocarbon,
in particular an alkane, and with constant thorough mix-
ing at room temperature, the carrier (I) and the alkanol
~3~ 83
- 6 - O.Z. 0050/39143
tII) are combined, from 1 to 5, in par~icular from 2.5
to 3.5, molar parts of the alkanol (II) being used per
molar part of magnesium of the carrier (I), and the sub-
stances combined are kept at from 20 to 140C, in particu-
lar from 70 to 90C, for from 0~5 to 5, in particular
from 1 to Z, hours, then
(1.2.2) in a second substage, with constant thorough m;x-
ing at room temperature, the titanium tetrachlor;de (III)
is introduced into the react;on mixture resulting from
the first substage, from 2 to 20, in particular from 4
to 8, molar parts of the titaniùm tetrachloride (III)
being used per molar part of magnesium of the carrier (I),
the substances combined are kept at from 10 to 150C, in
particular from 90 to 120C, for from 0.5 to 5, in par-
ticular from 1 to 2, hours, and the resulting solid-phase
intermediate is isolated with removal of the liquid phase,
with the proviso that the phthalic acid derivative (IV)
is in~roduced in the course of one or both of the substages
~1.2.1) and (1.2.2), from 0.01 to 1, preferably from 0.1
20 to 0.4, in particular from 0.25 to 0.30, molar part of
the phthalic acid derivative (IV) being used per molar
part of magnesium of the carrier (I), then
(1.3) in a third stage, the solid-phase intermediate ob-
tained from the second stage ;s subjected to a single-
stage or multi-stage or continuous extraction with titan-
ium tetrachloride or a mixture of titanium tetrachloride
and ethylbenzene, containing not less than 10, in particu-
lar not less than 20, % by weight of titanium tetrachlor-
ide, at from 100 to 150C, in particular from 115 to
30 135C, in the course of from 0.2 to 5, ;n part;cular from
1.5 to 3, hours, a total of from 10 to 1,000, preferably
from Z0 to 800, in particular from 150 to 300, parts by
weight of the extracting agent being used per 10 parts by
weight of the solid-phase intermediate obtained from the
second stage, and finally
(1.4) in a fourth stage, the solid-phase product formed in
the third stage is washed with a l;quid ;nert hydrocarbon,
~3~D4~33
- 7 - O.Z. 0050/39143
in particular an alkane, until the hydrocarbon takes up
virtually no more titanium tetrachloride, and the titan-
ium component (1) is obtained in this manner.
We have found that the novel process can be car-
ried out particularly successfully if the catalyst sys-
tem used contains a silane component (3) which is of the
formula
R~ Si(OR~ n
where R1 is phenyl or C1-C4-alkylphenyl, especially
methyl- or ethylphenyl, R2 is alkyl of not more than 4
carbon atoms, especially methyl or ethyl, and n is 1 or
2.
Regarding the process according to the invention,
the following may be noted specifically:
Provided that the defining feature is taken into
account, the polymerization process as such can be car-
ried out in virtually any relevant conventional techno-
logical embodiments, for example as a batchwise, periodic
or, in particular, continuous process eg. a suspension
polymerization process or, in parl:icular, dry-phase
polymerization process. The stated technolog;cal embodi-
ments, ie. the technological versions of the polymeriza-
tion of ~-monoolefins by the Ziegler-Natta method~ are
well known from the literature and in practice, so that
no further discussion is required here.
For the sake of completeness, it may be mentioned
that, in the novel process, it is also possible to regu-
late the molecular weights of the poly0ers by the rele-
vant conventional measures, for example by means of regu-
lators, ;n particular hydrogen~
Regarding the composition of the novel catalyst
system, the following may be stated specifically:
t1) the finely divided silica gel ~Ia) to be used for the
preparation of the titanium component is in general an
aluminosilicate or, in particular, a silica; it is im-
portant that it has the required properties. We have
~3~ 3
- 8 - O.Z. 0050/39143
found that the commercial silica gels which meet the
stated specification and are conventionally used for
carriers are very suiteble.
The organomagnesium compound (Ib) likewise to be
used may be, for example, dibutylmagnesium, dihe~ylmag-
nesium or, in particular, butyloctylmagnesium.
The gaseous chlorinating agent tIc) also to be
used should be very dry and pure; it consists of chlorine
or, in particular, hydrogen chloride.
The liquid inert hydrocarbon which serves as an
assistant can be a hydrocarbon of the type usually com-
bined with titanium components for catalyst systems of
the Ziegler-Natta type ~ithout damage to the catalyst
system or its titanium component. Examples of suitable
hydrocarbons are pentanes~ hexanes, heptanes, gasolines
and cyclohexaneu
The alkanols (II) to be used for the preparation
of the titanium compcnent (1) can be commercial ones;
they should advan~ageously have very high purities. Exam-
ples of highly su;table alkanols are ethanol, n-propyl
alcohol, isopropyl alcohoL, n-butyl alcohol, isobutyl
alcohol and tert-butyl alcohol; ethanol is particularly
suitable.
The titanium tetrachloride (III) l ikewise to be
used for the preparation of the titanium component (1)
should be one convent;onally used in Ziegler-Natta catal-
yst systems; the ethylben2ene which may be used as a mix-
ture ~ith the t;tanium tetrachloride should be very pure
and dry.
Further~ore~ the phthalic acid derivat;ve (IV)
to be used, which ;s defined in detail above, can be a
commercial one; it should advantageously have high pur-
ity. We have found that dibutyl phthalate is very par-
ticularly suitable for the purpose of the present inven-
tion; however, other dialkyl phthalates and phthalic an-
hydr;de and phthaloyl d;chlor;de are also su;table.
The hydrocarbon to be used for the preparation
~a3~ 8,3
- 9 - O.Z. 0050/39143
of the titanium component (1) in stage (1.4) can likewise
be a conventional one; it should advantageously have a
relatively high purity.
The preparation of the titanium component (1) is
S simple and can be carried out by the skilled worker with-
out explanations. Regarding stages (1.1), (1.2) and (1.3),
all that need be stated is that the isolation of the par-
ticular resulting solid is advantageously carried out by
filtration under suction~
(2) Suitable aluminum components (2~ of the stated
formula are the relevant conventional ones of this for-
mula; they are sufficiently well known from the literature
and in practice that no further discussion is required.
An example of an outstanding member is triethylaluminum.
(3) The silane component (3) which completes the
catalyst system is, in particular, a trialkyoxy(alkyl)-
phenylsilane or a dialkoxydi(alkyL)phenylsilane of the
stated formula. Triethoxytoluylsilane is an outstanding
member; other examples are triethoxyethylphenylsilane,
dimethoxyditoluylsilane and diethoxyditoluylsilane.
The novel process permits the preparation of homo-
polymers and copolymers, for e~am~)le of the binary or
ternary type, including block copolymers, of propene
with minor amounts of other C2-C~ monoolefins in an
advantageous manner~ a-monoolefins wh;ch are particu-
larly suitab~e comonomers to be polymerized being
ethene, but-1-ene, 4-methylpent-1-ene and hex-1-ene;
however, n-oct-1-ene, n-dec-1-ene and n-dodec-1-ene are,
for example, also suitable.
EXAMPLE 1
Preparation of the titanium component (1)
The procedure is as follows: first
(1.1) in a first stage (I), a carrier is prepared from
(Ia) a finely divided silica gel which has a particle
diameter of from 20 to 45 ~m, a pore volume of 1.75 cm3/g
and a surface area of 320 m2/g ar,d is of the formula SiO2,
(Ib) butyloctylmagnesium and (~c) hydrogen chloride, by
~3~ 3
- 10 - O.Z. 0050/39143
a method in which first
(1.1.1) in a first substage, in n-heptane and with con-
stant thorough mixing by means of stirring at room tem-
perature, the finely divided silica gel (Ia) and the organo-
magnesium compound (Ib) are combined, 2.5 molar parts ofthe organomagnesium compound (Ib) being used per 10 molar
parts of silicon of the silica gel tIa), and the substances
combined are kept at 90C for 1.5 hours, then
(1.1.2) in a second substage, with constant thorough mix-
ing by means of stirring at 10C, gaseous ch~orinatingagent (Ic) is passed into the product obtained from the
first substage, 10 molar parts of the chlorinating agent
(Ic) being used per molar part of the organomagnesium com-
pound (Ib), the entire mixture is left at a temperature
in the stated ran~e for 0.5 hour and the resulting solid-
phase product, ie. the carrier (I), is isolated with re-
moval of the liquid phase, thereafter
(1.2) in a second stage, a solid-stage intermediate is
prepared from (I) the carrier obtained in the first stage,
20 (II) ethanol, (III) titanium tetrachloride and (IV) di-n-
butyl phthàlate, by a method in which first
(1.2.1) in a first substage, ;n n-heptane and with con-
stant thorough mixing by means of stirring at room tem-
perature, the carrier (I) and the ethanol ~II) are com-
bined, 3 molar parts of the ethanol (II) being used perm~lar part of magnesium of th~ carrier (I), and the sub-
stances combined are kept at 80C for 1.5 hours, then
(1.2.2) in a second substage, ~ith constant thorough mix-
;ng by means of stirring at room temperature, the titan-
ium tetrachloride (III) is introduced into the reactionmixture resulting from the first substage, 6 molar parts
of the titanium tetrachloride (III) being used per molar
part of magnesium of the carrier (I), after which the
di-n-butyl phtha~ate is introduced, 0.30 molar part
of the phthalate (IV) be;ng used per molar part of mag-
nesium of the carrier (I), the substances combined are
kept at 120C for 2 hours with stirring, and the resu~ting
~3~ 3`3
- 11 - O.Z. 0050/39143
solid-phase intermediate is isolated with removal of
- the liquid phase by filtration under suction, then
(1.3) in a third stage, the solid-phase intermediate ob-
tained in the second stage is subjected to a continuous
extraction with titanium tetrachloride at 125C in the
course of 2 hours, 140 parts by weight of the titanium
tetrachloride being used per 10 parts by weight of the
solid-phase intermediate obtained in the second stage,
after which the resulting solid-stage intermediate is
isolated by filtration, and finally
(1.4) in a fourth stage, the solid-phase product obtained
in the third stage is washed with n-heptane until the n-
heptane takes up virtually no more titanium tetrachloride,
and the titanium component (1) is obtained in this man-
ner; it contains 3.5% by weight of titanium, 6.0X byweight of magnesium and 23~ by weight of chlorine.
Polymerization
A steel au~oclave, having a voLume of 10 l and
er~uipped with a stirrer, is charged with 50 g of poly-
propene powder~ 10 millimoles of triethylaluminum (in
the form of a 1 molar solution in n-heptane) as aluminum
component (2), 1 millimole of triethoxyphenylsilane (in
the form of a 1 molar solution in n-heptane), as silane
component (3), 5 liters (S.T.P.) of hydrogen and finally
100 mg (g 0.07 millimole of titanium) of the titanium
component (1) described above, at 30C. The reactor tem-
perature is brsught to 70C ;n the course of 10 minutes,
and the reactor pressure is brought to 28 bar in this
time by forcing in gaseous propene.
The actual polymerization is carried out with
constant stirring at 70C and under 28 bar in the course
of 2 hours, monomer consumed during this procedure being
continuously replaced with fresh monomer.
The productivity of the catalyst component (1),
the heptane-soluble fraction (as a measure of the iso-
tacticity) and the particle size distribution of the re-
sulting polymer are summarized in the Table below.
~31~8~33
- 12 - O.Z. 0050/39143
EXAMPLE 2
The procedure described in Example 1 is followed,
with the sole exception that the same molar amount of di-
methoxyditoluylsilane is used as silane component (3).
The result of the polymerization carried out in
this manner is likewise shown in the Table below.
COMPARATIVE EXPERIMENT
Preparation of the titanium component
The procedure described in Example 1 of European
Laid-Open Application 0,195~497 is followed.
The resulting titanium component contains 3.6%
by weight of titan;um, 4.4X by weight of magnesium and
16X by weight of chlorine.
Polymerization
This is carried out as described in Example 1,
but using, instead of the titanium component described
there, the same molar amount of the titanium component
defined abo~e.
The polymerization result achieved is once again
shown in the Table below.
~ :., .~.. - - . ,
~3048~
- 13 - 0. Z . 0050/39143
o
Q~
C V
o U E u~
U ~
~ ~ ~ `O
C O~ ~, ~
O
-
U~ 00 0
N
E ~ ~ ~--
~_
C ~ C~
O I O
~_
V U~ ~ O`
. U~
~ O
~:1
CJ U~
O ~ ~ ~0
I
Il~ O r- O~
U O
U~
`O O
~ o ~ r~
-
,_
O C V
0 3
, O` O O
u r
~J ~ a~
~ ~ _,
I
~ U
~ ~0
V O O O
U ~1 O O O
~ ~. O` ~ U~
O 1~ O ~i M
O
-
(I)
C
~ ~ ~ E
_ __' L ~ _
E E Q QJ
~ ~J E /:~
X X o X
~LI LLJ ~ ~
~L3~ 33
- 14 - O.Z. OOSC/39143
As shown in the Table, the catalyst component
from the Comparative Experiment has a substantially lower
productivity and stereospecificity than the catalyst com-
ponents fro0 the Examples according to the invention.
S Moreover, the particle size distribution is shifted to
a range of undesirably large particles.
