Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
~9~7~33
HOECHST AKTIENGESELLSCHAFT HOE 86tF 134 Dr.DA/mu
Process for the preparation of a polyolefin
The present invention relates to a process for ~he prepa-
ration of a polyolefin by means of a highly active, sphe-
rical Ziegler ca~alyst, by means of which considerables;mplifications and advantages in handling and processing
the products are achieved.
A large number of catalysts of the Ziegler type for the
polymerization of alpha-olefins are already known.
Many of these catalysts are based on magnesium chloride,
as the support;ng material, this being obtained by react-
ing an organomagnesium compound R2Mg, such as, for ex-
ample, butylethylmagnesium, with a chlorinated hydrocarbon
compound R'-Cl, such as, for example, carbon tetrachloride
tcf US Patents nos. 4~442,225 and 4,439,539 and German
Offenlegungsschrift 3,010,202)~
It is not possible, however, in this way to obtain a mag-
nesium chloride having a spherical shape.
On the other hand, it is known that globular magnesium
chloride is formed when an organomagnesium compound R2Mg
is reacted with a chlorinated organic compound R'-Cl in
the presence of an organoaluminum compound, such as trie-
thylaluminum, and an electron donor, sucn as diisoamyl
ether (cf European Published Specification 99,284).
Limitations applying to this are that R' must be a hydro-
carbon radical having three or more carbon atoms and the
carbon atom adjacent to the chlorine must be ei~her a se-
condary or tertiary carbon atom.
It is also known that catalysts can be prepared by reac-
ting magnes;um chloride with alkoxy compounds of the ele-
ments of the I to VI main group and/subgroup of the perio-
dic system, followed by treatment with a compound of ti-
tanium~ zirconium or vanadium (cf Ger~an OffenLegungsschrift
' \ ~
~Z91~Z33
-- 2
3,025,759). In addition to a low contact catalyst
activity (< 5 kg of polymer/mmol of Ti), however, the ca-
talyst granules in these catalysts do not have a spherical
shape. Furthermore, these catalysts only afford products
S having a broad distribution of molecular weight which are
unsuitable for certain applications, such as, ~or example,
precision inje~tion molding or the blow-molding of spe-
cial hollow articles.
Finally~ it is possible to obtain, in a very involved pro-
cess of preparation, a catalyst based on magnesium chloride
and having spherical granules. This requires a two-stage
reduction reaction with alkyl aluminum halides and organo-
metallic compounds of magnesium, zinc or aluminum, followed
by pre-polymerization, again in one or two stages (cf
European Published Specification 143,002). However, this
catalyst can only be employed in the gas phase copolymeri-
zation of ethylene with higher alpha-olefins. Disadvan-
tages in the resulting copolymers are, additionalLy, the
high residual content of titanium in the polymer, the low
density and the broad particle size distribution of the
polymer .
It has now been found that it is possible to prepare in a
simple manner a highly active and, at the same time, spheri-
cal catalyst by means of which it is possible to obtain
globular polymers of alpha-olefins which are distinguished
by a narrow particle size distribution and, at the same
time, a large average particle diameter.
The ;nvention therefore relates to a process for the pre-
paration ot a polyolefin by polymerizing alpha-olefins at
a temperatur~ from 50 to 150C and under a pressure of
1 to 40 bar in the presence of a catalyst composed of a
transition metal component (component A) and an organome-
tall;c compound (component B) in which the component A has
been formed by reacting an organomagnesium compound with
an organoaluminum compo~nd, an electron donor, an organic
chlorine compound and a transition metal compound, which
~%~ 33
-- 3
comprises carrying out the polymerization in the presence
of a catalyst in which the component A has been prepared
by
a) reacting an organomagnesium compound of the formula
R1MgR2 in which R1 and R2 are ident;cal or different
alkyl radicals having Z to 12 carbon atoms with an organo-
aluminum compound of the formula AlR3n(0R4)3_n in which R3
and R4 are identical or different alkyl radicals having
1 to 8 carbon atoms and n denotes 0, 1, 2 or ~, or with
the product from the reaction of aluminum trialkyls or al-
uminum dialkyl hydrides with diolefins containing 4 to 20
carbon atoms, and a primary, aliphatic chlorinated hydro-
carbon in an amount of 0.01 to 15 mol of the organoaluminum
compound and 0.5 to 2.5 mol of the chlorinated hydrocarbon,
relative to 1 mol of the organomagnesium compound, at a
temperature from 30 to 110C,
b) treating the resulting solid with an electron donor in
an amount of 0.1 to 1 mol per gram atom of the magnesium
present in the solid, at a temperature from 0 to 100C,
and
c) reac~ing the support;ng material thus obtained w;th a
compound of t;tanium or zirconium or the formula MeXm
~OR5)4 m in which Me is Ti or Zr, RS is an alkyl radi-
cal having 2 to 10 carbon atoms, X is a halogen atom and m
is an integer from 0 to 4, in an amount of 0.1 to 2 mol
per gram atom of the magnesium present in the supporting
material, and at a temperature from 30 to 120C.
A solid of spherical shape ;s in;tially formed. For this
purpose, an organomagnesium compound is reacted with an
organoaluminum compound and a primary, aliphatic chlori-
nated hydrocarbon.
The organomagnesium compound is a magnesium dialkyl of
the formula R1MgR2 in which R1 and R2 are ;den~ical or
d;fferent alkyl radicals hav;ng 2 to 12 carbon atoms.
Di-n-butylmagnes;um, di-n-octylmagnesium, n-butyl-n-octyl-
magnesium, n-butyl-ethylmagnesium, n-butyl-sec-butylmagnesium
~297~3;~
-- 4
or mixtures of these compounds are preferred.
A suitable organoaluminum compound is an alkyl aluminum or
alkoxy aluminum compound of the formula AlR3 n(oR4)3_n
in which R3 and R4 are identical or different alkyl
radicals having 1 to 8 carbon atoms and n denotes 0, 1,
Z or 3. The product from the reaction of aluminum-tri-
alkyls or aluminum dialkyl hydrides having hydrocarbon ra-
dicals with diolefins containing 1 to 6 carbon atoms, pre-
ferably isoPrene, is also equally suitable. Aluminum iso-
prenyl may be mentioned as an example.
Examples of suitable primary, aliphatic chlorinated hydro-
carbons are carbon tetrachloride, chloroform, methylene
chlor;de, 1-chloropropane or 1,1,1-trichloroethane, and it
is also possible to employ mixtures. It is preferable
to use chloroform and 1-chloropropane.
The spherical-shaped solid is prepared by dissolving the
organomagnesium compound and the organoaluminum compound
in an inert, liqu;d hydrocarbon under an atmosphere of ni-
trogen or argon. This solution is combined, while simul-
taneously stirr;ng at a temperature from 30 to 110C, pre-
ferably from 40 to 80C, with a solution of the chlori-
nated hydrocarbon~ The reaction can be carried out byadding the chlorinated hydrocarbon to the solution of the
organomagnesium and organoaluminum compound in the liquid
hydrocarbon, or vice versa.
It is possible to vary both the reaction time and the de-
gree of dilution of the reactants within wide limits in
this reaction. The reaction time is 30 minutes to several
hours, preferably 1 hour to 5 hours. The reactants are em-
ployed in the form of 0.5-molar to 15-molar solutions.
The mixture contains up to 0.15 mol, preferably up to 0.10
mol, of the organoaluminum compound and up to 2.5 mol,
preferably up to 2.0 mol, of the chlorinated hydrocarbon,
relative to one mol of organomagnesium compound.
~97~3~3
-- 5 ~
The solid formed is composed essentially of magnesium
chloride together with a little aluminum chloride. Before
being reacted further, it is preferably washed several
times with a liquid hydrocarbon.
s
The solid is composed of spherical particles having an
average diameter o~ 20 to 110 ~m, preferably 60 to 90 ~m.
The ratio o~ the mass average diameter, Dm~ to the number
average diameter, Dn~ is less than 1.5 and is preferably
between 1.01 and 1.15~ The ratio of greatest to small
diameter D/d is within the range from 1.05 to 1.15.
The spherical-shaped solid is then suspended in a liquid
hydrocarbon, the concentration not being decisive for
further reaction. It is preferable, however, tn use a sus-
pension which is as concentrated as possible and at the
same time readily stirrable and which contains 0.1 to 1.5,
preferably Q.3 to 0.9, mol of magnesium chloride per litre
of liquid hydrocarbon.
An electron donor is then added to the suspension of the
spherical-shaped solid~ Suitable electron donors are oxy-
gen-containing compounds of aluminum, silicon, phosphorus
or sulfur, nitrogen or silicon compounds having alkyl
or aryl radicals containing 1 to ~ carbon atomsr such as,
for example, triethylamine or hexamethyldisilane, or ali
phatic or aromatic ethers containing identical or different
organic radicals.
It is preferable to use alkoxyaluminum compounds, dialkyl
sulfites, aliphatic ethers and alkyl silicates.
The electron donor is added to the spherical-shaped solid
in a molar ratio of 0.1 to 1, preferably 0.1 to 0.6, re-
lative to 1 gram atom of magnesium, at a temperature from0 to 100C, prefera~ly from 30 to ~0C.
Depending on the react;vity of the reactants, the reaction
time is 0.5 to 5 hours, preferably 1 to 3 hours.
~2~Z33
6 --
The spherical-shaped supporting material obtained in this
manner is either washed several times with an inert liquid
hydrocarbon at O to 100C, preferably at 20 to 60~C,
or is immediately reacted, under an atmosphere of nitrogen
or argon, with a compound of titanium or zirconium of the
formula MeXmtORS)4_m in which Me is Ti or Zr, R5 is
an alkyl radical having 2 to 10 carbon atoms, X is a halo-
gen atom, preferably chlorine, and m is an integer from
O to 4, but preferably 2 or 4. It is possible to employ a
mixture of several of these compounds.
Examples of preferred compounds are TiCl4, TiCL3(0Et),
TiCl3(0-iPr), TiCl2(0Et)2, TiClz(O-iPr)2, TiCl2(0-CH2CH6H5)z,
TiCl(o-i9u)3, Ti(OEt)4, Ti(O-Pr)24 or Ti(O~iPr)4.
TiCl4, TiCl2(0Et)2 and Ti(OEt)4 or a mixture of
these compounds are very particularly preferred.
In the reaction described above, the titanium or zircon-
ium compound is employed in an amount of 0.1 to 2 mol,
preferably 0.2 to 1.8 mol, relative to one gram atom of
magnesium in the spherical-shaped supporting mater-
ial.
The reaction temperature is 30 to 120C, preferably 60
to 95C, and the reaction time is 30 minutes to several
hours, preferably 1 to 5 hours, depending on the required
coating of titanium or zirconium.
The catalyst component A prepared in this manner is finally
freed from soluble impurities, such as metal compounds or
halogen compounds, by repeated washing with an inert hydro-
carbon at a temperature from O to 100C, preferably -from
10 to 50C.
The catalyst component A prepared in accordance with the
invention is in the form of spherical particles which have
an average diameter of 20 to 110 ~m, preferably 60 to 90
~m, and in which the ratio of mass average diameter,
~;~g7Z33
-- 7
Dm~ to number average diameter Dn~ is less than 1.5,
preferably 1~01 to 1.2. The ratio D/d is within the
range from 1.02 to l.12.
The component A is employed for the polymerization o~ alpha-
olefins in the form of a suspension in an inert hydro-
carbon, or, after removing the suspending agent, in the
dry state. The polymerization of ethy~ene or propylene is
preferred, or the copolymerization of ethylene and/or pro-
pylene with an alpha-olefin having 4 to 10 carbon atoms
and one or more double bonds, such as, for example, 1-
butene, isobutene, 1-he~ene or 1,3-butadiene.
The polymerization can be carried out either continuously
or discontinuously in the gas phase or in saturated hydro-
carbons having 3 to 15 carbon atoms, such as, for e~ample,
propane, butanes, pentanes, hexanes, heptanes, cyclohexanes
or mixtures of such compounds.
2Q In general, hydrogen is also additionally employed as a
molecular weight regulator, and an aluminum compound of
the formula AlR6 pY3_p in which p is 1, 2 or 3 and
R is an alkyl or aryl radical having 1 to ~0 carbon
atoms and Y is hydrogen, a halogen atom or an alkoxy or
aryloxy group each of wh;ch has 1 to Z0 carbon atoms, is
employed as the component b (co-catalyst).
Examples are halogen-containing organoaluminum compounds,
such as dialkyl aluminum halides, alkylaluminum dihalides
or alkylaluminum sesquichlorides, and also aluminum tri-
alkyls or aluminum alkyl hydrides, which can be em-
ployed on their own or as a mixture~
It is preferable to use aluminum trialkyls, such as, for
example, aluminum triethyl or aluminum triisobutyl.
The polymerization temperature is 5~ to 15~C, preferably
S0 to 100C, and the pressure is 1 to 40 bar~ preferably
3 to 1Z bar~
~297~3
The polymers and copolymers prepared in the process ac-
cording to the invention are distinguished by a compact,
uni-form, spherical shape, together with a very narrow
particle size distribution. The ratio of mass average
d;ameter, Dm~ to number average diameter Dn~ is less
than 1.5, preferably 1.02 to 1.3. The ratio D/d is
within the range from 1.05 to 1.2. The diameter of the
polymer particle is within the range from 100 to 1800 ~m,
preferably 600 to 1500 ~m. The polymers have a high bulk
density and can be processed in an excellent manner.
A further advantage of the catalyst according to the in-
vention is its high contact catalyst activity, so that
only very small amounts of the catalyst are required for
the polymerization. As a result, it is not necessary ei-
ther to subject the polymers to an additional after-treat-
ment, such as, for example, involved washing or pur;fying
operations. Nor does any undesirable discoloration of
the product occur through residues of catalysts, which can
frequently result in the stabil;ty to light of the polymers
being impaired.
The residual content of titanium or zirconium in the poly-
mers prepared in accordance with the invention is less
than 4 ppm, frequency less than 2 ppm.
Above all, however, considerable simplifications and ad-
vantages in handling~ drying and processing are achieved
by virtue of the spherical shape and the associated very
good free flow of the polymers and copolymers.
The invention is illustrated beLow in greater detail by
means of the examples.
The melt flow index MFI ~190/5) was determined as specified
in DIN 53 735 at 190C and at a loading of 5 kp.
The ratio of Dm to Dn was determined as specified in
NF X 11-630 dated June 19~1:
~%~7233
Dm= [~ni (Di)3Di]/[~ni (Di)3]
Dn= [~ni Di]/~ni
ni = number i of samples of identical diameter
Di = diameter of the i-th sample.
The particle size dis~ribution Dm/Dn of the component A
was determined by image analys;s us;ng an IBAS 1. The
particle size distribution Dm/Dn of the poLymer was
determined by sieve anaLysis as specified in DIN 4188.
~e~.
10.5 mmol of alunimum triethyl were added to 200 ml of
a solution of di-n-butylmagnesium in heptane (corresponding
to 105 milligram atoms of Mg), and the mixture was added
dropwise, with vigorous stirring and in the course of 90
minutes, at 45 + 10C to a mixture of 165 mmol of 1-
chloropropane and 30 ml of petroleum ether. The mixture
was stirred for a further 3 hours at 80C and the solid
was extracted by washing 5 times with a total of 12ûO ml
of petroleum ether.
This gave a spherical-shaped solid having an average dia-
meter (dso) of 60 ~m.
Mg : Cl : Al = 1 : 2.14 : 0.04
Dm/Dn = 1.13, D/d = 1.1
Example Z
8.5 mmol of aluminum triisopropylate were first added to
200 ml of a solution of butyloctylmagnesium in heptane
(corresponding to 185 milligram atoms of Mg~, and the mix-
ture was stirred for 40 m;nutes at 50~C. 370 mmol of
chloroform were then added dropwise in the course of 75
minutes at 70 + 5C, the mixture was stirred for two hours
at 85 C and the spherical-shaped solid was washed with
800 ml of petroleum ether.
Mg : Cl : Al = 1 : 2.2 : 0.06
dso = 80 ~m
~2~37~3
- 10 -
Example 3
.
670 ml of a solution of butyloctylmagnesium in heptane
(corresponding to 570 milligram atoms of Mg), containing
28.5 mmol of aluminum triisobutyl, were added dropwise,
with uniform stirring and in the course of three hours,
at 70 ~ 5C to a mixture of 200 ml of 100/200 petroleum
ether and 70 ml (860 mmol) of chloroform~ The brown sus-
pension was stirred for a further three hours at 75C,
and the solid was washed 5 times with a total of 2500 mL
of petroleum ether.
Mg : Cl : Al = 1 : 2.05 : 0.03
D /D - 1 0
~50 = 90 ~m
Example 4
The procedure was analogous to that of Example 3, but 650
mmol of carbon tetrachloride were used instead of chloro-
form.Mg : Cl : Al = 1 : 2.29 : 0.05
Dm/Dn = 1.14
dso = 70 ~m
Example S
200 ml of butyloctylmagnesium in heptane (corresponding
to 175 milligram atoms of Mg), contain;ng 7 mmol of iso-
prenylaluminum, were added dropwise, at 75C and in the
course of 60 minutes, to a mixture of 60 ml of petroleum
ether and 30 ml (370 mmo() of chloroform. The mixture
was then stirred for 60 minutes at 80C and for a further
4 hours at 90C. The spher;cal~shaped solid was ~ashed
5 times with a total of 1500 ml of petroleum ether.
35 Mg : Cl : Al = 1 : 2.03 : 0.01
Dm/Dn = 1.03
dso = 75 ~m
~Z~33
Example 6
25 mmol of aluminum triisopropylate were added at 40C to
300 ml of a suspension of the solid prepared in Example 1
in 100/200 petroleum ether (corresponding to 80 milligram
atoms of Mg), and the mixture was then stirred for two hours
at 95C, and the suspension was cooled to 50C. 120 mmol
of titanium tetrachloride, dissolved in 20 ml of petroleum
ether, were added dropwise at this temperature in the
course of 3û minutes. The mixture was stirred for a
further 4 hours at 90C, and the deep violet precipiate
was washed with S times 200 ml of petroleum ether. The
spherical-shaped catalyst component A had an average
particle diameter (dso) of 60 ~m.
Mg : Ti : Cl : Al = 1 : 0.07 : 2.68 : û.02
Dm/Dn = 1.1
dso = 80 ~m
Example 7
-
80 mmol of diethyl sulfite were added at 20C to S00 ml
of a suspension in petroleum ether of the solid prepared
in Example 2 (corresponding to 200 milligram atoms of Mg),
and the mixture was stirred for two hours at 80C.
The dark gray suspens;on was cooled to 5nc and washed
with 1~00 ml of petroleum ether. 230 mmol of titanium
tetrachloride were then added dropwise at this temperature
in the course of 30 minutes. Further reaction at 95 C
afforded a violet, spherical-shaped catalyst component A,
which was washed in suspension with S times 200 ml of pe-
troleum ether.
Mg : Ti : Cl : Al = 1 : 0.07 : 2.28 : O.D2
DmtDn ~ 1.1
dso = 80 ~m
the procedure was analogous to that of Example 7, but the
~Z~7233
- 12 -
solid from Example 5 was employed instead of the solid
from Example 2.
Mg : Ti : Cl : Al = 1 : 0.11 : 2.05 : 0.02
Dm/Dn = 1-04
dso = 70 ~m
Example 9
.
120 mmol of dipropyl sulfite were added at 35C to 500 ml
of a petroleum ether suspension of the solid prepared in
accordance with Example 3 (corresponding to 200 milligram
atoms of Mg)~ and the mixture was stirred for 90 minutes
at 80C. The gray suspension was then washed several
times with petroleum ether at 60C. A mixture of 270
mmol of titanium tetrachloride and 30 mmol of titanium
tetraethylate, dissolved in 50 ml of pe~roleum ether, was
added dropwise at ~his temperature in the course of 30
minutes. The mixture was stirred for 60 minutes at 80C
and for 120 minutes at 95C, and the violet precipitate
was then washed with 10 times 200 ml of petroleum ether.
Mg : Ti : Cl : Al = l : 0.2 : 2.5 : 0.04
Dm/Dn = 1-2
dso = 90 ~lm
Example 10
The procedure was analogous to that of Example 6, but the
solid from Example 4 was employed instead of the solid
from Example 1.
Mg : ri : cl : Al = 1 : 0.13 : 2~35 : 0.14
Dm/Dn = 1.15
dso ~ 70 ~m
Example 11
..
The procedure was analogous to that of Example 7, but 60
mmol of diethyl silicate were employed instead of diethyl
sulfite.
Mg ~ Ti : Cl : Al = 1 0.08 : 2~13 : 0.02
~Z~7Z33
- 13 -
Example 12
The procedure was ana~ogous to that of Example 11, but a
mixture of 210 mmol of dichlorodiethoxytitanium and 30 mmol
of titanium tetrachloride was employed instead of titanium
tetrachlori~e.
Mg : Ti : Cl : Al = 1 : 0.05 : 2.33 : 0.03
Example 13
The procedure was analogous to that of Example 6, but em-
ploying the solid from Example 3 and 40 mmol of diisobutyl
ether instead of aluminum triisopropylate.
Mg : Ti : Cl : Al = 1 : 0.09 : 2.46 : 0.01
Example 14
-
The procedure was analogous to that of Example 6, but em-
ploying the solid from Example 3 and a mixture of 120
mmol of titanium tetraethylate and 30 mmol of titanium
tetrachloride instead of titanium tetrachloride.
Mg : Ti : Cl : Al = 1 ; 0.19 : 2.17 : 0.08
Examples 15 to 34
The polymerization of ethylene was carried out in 1,000 ml
of petroleum ether under the conditions mentioned in the
table in a 1.5 litre steel autoclave ;n the presence of
hydrogen as molecular weight regulator and at a temperature
of 85C and a pressure of 7 bar. 4 mmol of ~riethyl-
aluminum (TEA) or 3 mmol of triisobutylaluminum tTI8A) wereadded as component B. The bulk density of the globular
polyethylene was 300 to 450 g/l and its density was 0.~10
to 0.9~5 g/cc. The D/d was within the range from 1.05 to
1.2.
The content of material finer than 300 ~m was less than
OnO1 %~ The residual content of titanium in the polymer
was less than or equal to 4 ppm.
7~
- 14 -
Exa~Le Catalyst Ti H 2 Time Yield MFI (190/5) Dm/d50
no. caTponent [mrnol~ tbar] [hr.] [9 of PE/ [9/10 m;ns.] Dn [~m]
A accorc~ mmol of
ing to Ti~
ex~r~le
6 O.C05 2.5 2 21900 2.95 1.09 910
16 7 0.002 1 .4 2 75800 0.05 1.04 150D
1 017 7 0.03 5.6 5 231m220 1.18 800
18 8 0.05 3.85 1 19200 701.17 980
19 8 0.005 2~5 3 64600 2.31.02 1190
8 0.03 5.8 2 121Q0 2301.03 750
21 9 0.003 2.5 5 38200 0.98 1.09 1150
1 522 10 0.004 2.5 5 49200 1.15 1.2 750
23 10 0.01 3.85 2 22400 16 1.2 810
24 11 0.05 3.85 2 18400 171.18 880
11 0.005 3.85 5 39500 191.12 920
26 11 0.005 1 .4 5 68800 0.18 1.08 14m
2 027 12 0.003 1.4 2 30660 0.12 1 .1 1220
28 12 0.025 3.85 2 20100 201.13 1100
29 12 0.01 3.85 5 33900 221.09 980
12 0.001 5.25 5 16300 1701.18 770
31 13 0.005 2.5 2 239Q0 1.91.08 1030
2 532 13 0.005 3.85 5 39200 14 1.1 940
33 14 0.01 1.4 2 17800 0O05 1.3 680
34 14 0.01 5.8 3 11500 1981.3 710
~Z~7Z33
- 15 -
Example 35
~ _ .,
10 litres of liquid propylene, 20 ml of triethylaluminum,
5.3 ml of methyl p-methylbenzoate and the catalyst compo-
nent A (0.001 mmol of Ti) from Example 7 were initially
placed in a 15 litre steel autoclave. After injecting
hydrogen to a pressure of 0.5 bar, polymerization was car-
ried out at 70C for 1 hour. 800 9 of polypropylene
having an average diameter (d50) of 550 ~m were obtained.
The bulk density was 380 g/l.
