Note: Descriptions are shown in the official language in which they were submitted.
HO~CHS~ AKTIENGESELLSCHAFT HOE 89/F 173 Dr.DA/gm
De~cription
Proces~ for the manufac~ure of a poly-l-olefin
The invention relates to a process for the manufacture
S of a poly-1-olefin using a Ziegler ~uppor~ed catalyst
based on a magnesium alcoholate and TiC14.
Processes for the ~anufacture of poiy-l olefin~ with a
broad molecular weight distribution u~ing Zi~gler ~uppor-
ted catalysts based on a magnesium alcoholate and TiCl4
are state of the art.
A process of this type is known which uses a catalyst
whose transition metal component was manufactured by re-
acting a magnesium alcoholate with titanium tetrachloride
at a temperature o~ 50 to 100C, separating off and
wa~hing the ~olid, tempering the ~olid at 110 to 20~C
~ with the additîon of TiC14, and ~horoughly washi.ng the
; solid ~q.v. CA 120749g~.
similar proces6 is also known which uses the ~ame re-
action product of a magnesium alcoholate and TiCl4, except
that it was tempered without further additions rather
~ than with the addition of TiC14. This was follow~d by a
,~ ~ thorough extraction by washing (q,v. US 4.447.587).
' ~ Both known catalyst ~ystems have the disad~antag0 that
' ~ their manufacture involves large amounts of wash solu-
tions which have to be worked up. The manufacturing
process iB also time-consuming.
,,
~: The ob~ect was to find a possible way o~ manufacturing
the knvwn catalysks in a ~horter time while saving raw
~!~ materials and auxiliaries and avoidîng wa~te.
It has been found that the object can be achieved by
removing only part of the soluble titanium comp~unds
. . .
~; ,
.~ ,. .
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-- 2 --
contained in the solid, after the first reaction step,
and subjecting the solid to a heat ~reatmen~ in a liquid
phase with a low titanium content.
The invention thus relates to a process ~ox the manu-
facture of a poly-1-olefin by the polymerization of a 1-
olefin of the formula R4CH=CH~, in which R" is hydrogen or
an alkyl radical having 1 to 10 carbon atoms, in SU8-
pension or in the gas phase, at a tempera~ure of 20 to
200C and a pressure of 0.5 to 50 bar, in the pre~nce of
a catalyst consisting o~ the reaction product of a mag-
: nesium alcoholate and titanium tetrachloride (component
a~ and a me~al-organic compound of a metal fr~m group I
- to III of the periodic table (component b~, wherein the
~` pol~merization i8 carried out in the pxesance of a
catalyst whose componen~ a has been manufacture~d by
reacting a magnesium alcoholate with titanium tetra-
~ chloride in a hydrocarbon a~ a temperature o 50 to
:: 100C, in a first reaction step, and ~hen separating o~
:~, part of the soluble constituents and subjecting the
:~` 20 resulting solid to a heat treatment at a temperature of
110 to 200C for 8 to 100 hour~, in a second re~ction
step.
: Component a is manufactured using a magnesium alcoholate.
This magnesium alcoholate can be a ~Isimple~ ma~nesium
. 25 alcoholate of the formula Mg~ORl)(OR2), in which R1 and R2
~:~ are identical or different and are an al~yl radical
having 1 to 6 carbon atoms. Examples are Mg(OC2H5)2,
Mg(O-i~C3H7)2, Mg(o-n-c3H7)2~ My(o-n-c4H~)2~ Mg~OCH3) (Oc2H5)
and Mg(OC2H5)~O-~-C3H7). It i8 al80 possible to use a
"~imple" magnesium alcoholate of the formula Mg(OR~X~, in
whish ~ = halogen, (SO4)l/2, OH, (CO3)~/2, (PO4)~/3 or Cl~ R
, ~ i8 as defined abo~e and n
~ m = 2.
'`:
A further possibility, however, is to use a "complexl'
magnesium alcoholate. "Complex" magnesium alcoholate is
understood as meaning a magnesium alcoholate containing
:
.
, ~ .
.
2~
~ 3 -
at least one metal from main group I to IV of the
periodic table, in addition to magnesium. Examples of
such complex magnesium alcoholates are: ~Mg~O-i-
~3~I7)4]Li2r [Al2t-i-C3H7~83Mg, [si~oc~H5)6]Mg~ tMg(0~2H5)~]1Na/
S [Al2(o-i-c4H~ Mg and tAl2(O-seC- C4Ha)6(C2~Is)2]Mg- The
complex magnesium alcohola~es (alkoxide ~alt9 ) are
manufactured by known methods. The following example~
may be mentioned for ~he manufacture of the complex
magnesium alcoholate:
lQ 1. Two metal alcoholates are allowed l:o react in a
suitable ~olvent, for example:
2Al(OR)3 + Mg(OR~2 ~ [Al2(R)s]Mg
2. Magne~ium is dissolved in an alcoholic solution of a
metal alcoholate:
2~iOR -~ Mg ~ 2ROH ~ [MgtOR)43Li2 ~ H2
3. Two met~ls are ~imultaneously dissolved in alcohol:
8ROH ~ Mg + 2Al ~ ~Al2(OR)~]Mg ~ 4H2
It is preferred to use the simple magnesium alcoholate~,
especially Mg(UC2H5)2, Mg(O-n-C3H7)2 and Mg(O-i-C3H7)2- The
magnesium alcoholate i8 used in pure form or attached to
a support.
~: Component a is manufactured in two reaGtion steps at
different temperatures.
In the first reaction ~tep, the magnesium alcoholate is
reacted with titanium tetrachloride at a temperature of
5~ to 100C, preferably 60 to 90C, in the pre ence of an
; iner~ hydrocarbon, with stirring. ~.9 to 5 molt pre-
ferably 1.4 to 3.5 mol, of titanium tetrachloride are
. ~ used per mol of magnesium alcoholate.
A ~uitable inert hydro~arbon is an aliphatic or cyclo-
~ aliphatic hydrocarbon such as butane,. pentane, hexane,
¦~" heptane, isooctane, cyclohexane or methyl~yclohexane, or
;; ~
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. . . .
} ,' ~
i
35;~
an aromatic hydrocarbon such a~ toluene or xylene;
hydrogenated diesel oil fxactions or gasoline fractions
from which oxygen~ sulfur compounds and moisture have
been carefully removed are also useful.
The reaction time in the first step i8 0.S to 8 hour6,
preferably 2 to 6 hours.
In the ~irst reaction step, an extensi~e exchange takes
place between the alkoxy groups of the magnesium alco-
holate and the chlorine atoms of the titanium tetra~
chloride, the reaction product obtained being a hydrs-
carbon-insoluble solid containing magnesium and titanium,
and hydrocarbon-soluble titanium ester chlorides.
Part of the unreacted soluble titanium compounds is $hen
removed from the hydrocarbon-insoluble reaction product
~:~ 15 of the magnesium alcoholate and the titanium tetra-
:~ chloride. Thi~ can be carried out by washing with an
inert hydrocarbon. This method leave~ behind, in the
~:~ solid, part of the titanium ester chlorides formed and
makes it possible to control the extent to which com-
:~ 20 ponent a is coated with titanium. Alternatively, it i~
also possible for all the suspending medium containing
the soluble titanium compounds to be removed from the
:~ hydrocarbon-insolubl~ reaction product, e.g. ~y fil-
tration. In ~his case, the amount of filtrate required
~ 25 to ad~ust the extent to whlch component a i~ coated with
- titanium is added be~ore tempering.
:
In a second reaction step, the solid obtained is sub-
: ~ected to a heat treatment at a temperature of 100 to
200C, preferably 110 to 160C, with stirring. The re-
action time i8 8 to 100 hours, preferably 10 to 40 hours.
In this stepl the solid i8 in a liquid phase with a low
titanium content. After this ~empering, the solid phase
of the su~pension has the desired titanium content and
the liquid phase of the suspension obtained has a suf-
ficiently low content of t.itanium-containing compounds.
:,. .
35~;~
- 5 -
It is not necessary to wash the catalyst.
This procedure gives a hydrocarbon-insol~ble solid con-
taining ma~nesium and titanium, which is called component
a.
The polymerization catalyst to be used according to the
invention is manufactured by bringinia component a to-
gether with a metal-organic compound of a ~etal from
group I to III of the pexiodic table (component b).
Component a can be reacted a~ a suspension direct with
oomponent b; however, it can first be i~olated as a
solid, stored and resuspended for subsequent u6e.
:~ It is preferred to u~e aluminum-organic compounds as com-
pDnent b. Suitable altumintum-organic c~mpounds are
chlorinated aluminum-organic compound~, dialkylaluminum
monochlorides of the foxmula R3~1Cl or alkylaluminum
sesquichloride~ of the ormula R33Al2Cl3~ in which R3 iB an
aIkyl radical having 1 to 16 carbon ~tom~. Examples
~ which may be mentioned are (C2H5)~1Cl, (i C4H6)~1Cl and
.~ (C2H5~3Al~Cl3. It is also po~sible t~ t~e mlxtures of
these compounds.
,~ ~
It is especially preferred to u~e chlorine-free compounds
as aluminum-or~anic compounds. Some chlorine-free com-
pounds suitable for this purpose are khe reactien
products of aluminum trialkyls or altuminum dialkyl
hydr~de~ with hydrocarbon radicals ~aving l to 6 carbon
, ~ a~oms, preferably Al(i-C4H~)30r Al(i-C4H~)2H, and diol.efin6
,; containing 4 to 20 carbon atoms, preferably i~opren~. An
example which may be mentioned is aluminum i~opren~l.
` ~ Other 3uitable chlorine-free aluminum-oxganic compounds
are aluminum trialkyls AlR33 or aluminum dialkyl hydride~
; of the formula AlR32H, i~ which R3 is an alkyl radical
~: having 1 to 16 carbon atoms~ ~xamples are Al~C2H5)3,
(C2Hs)2N~ Al(C3H~)3, ~l(C3H7)2H, Al~i-C4Ha~3, Al(i-C4H9)~H,
,,
$
~, . . , . - . . ;
,. ~ . . , , - ~ :
~135~:~
6 --
Al(C8H17)3, A1(Cl2H2s)3~ Al(~2H5)(C1~H2s)Z and Al(i-C4H9)-
( C12H25 ) 2 -
It is also possible to use mixtures of metal-organic com-
pounds of me~als from group I to III of the periodic
table, in particular mix~ures of different alumi~um-
organic compounds.
,
The following mix~ures may be mentioned as e~amples:
Al~C~s)3 and Al~i-C4H~)3, Al (C2~5~2Cl an~ Al(Ca~17)3, Al ~CzHs)3
: and Al~C8H1,) 3 ~ Al(C4Hg)2H and Al ( C8~l7 ~ 3~ Al(i-C4H9) 3 and
Al(C8H17~3, Al(C2H5)3 and A1(C1aH2s)3~ ~C4Hs)3 and
Al(ClaH25~3~ Al(C2H5) 3 and Al~ClsH333 3, Al ~ C3H7 ) 3 and
(Cl8H37)2(i-C4Hg), and Al(C2~5)3 and aluminum isoprenyl
(reaction product o~ isoprene and Al(i~C4Hg)3 or
: Al(i-C4Hg)2~)
Component a and component b can be mixed before polymeri-
~:~ zation, in a stirred kettle, at a temperature of -30C to
:~ 150C, pre~erably -10 t~ 120UC. ~t i~ also possi~le to
,~ bring the two components to~ether direct in the poly-
` : merization kettl.~ at a polymerization temperature of 20
~i 20 to 200C~ ~ow~ver, a further pos~ibility i8 to add com-
; ~ ponent b in two 6tep6 by preactivating component a,
~: before the pol~merization reaction, with part of com-
;~ ponent b at a temperature of -30C to 150~C and adding
the remainder of component b in the polymerization re-
~ 25 actor at a temper~ture of 20 to 200~C.
,: ~
, The polymerization catalyst to be employed according to
,; the invention i5 u~ed for the polymerization of 1-olefins
of the formula R4CH=CH2, in which R~ is a hydrogen atom or
~:: an alkyl radical having 1 ~o 10 carbon a~oms, examples of
said l-olefins being ethylene, propylene, but~1-ene,
hex~1-ene, 4-methylpent 1-ane and oct-1-ene.
It is preferred to polymerize ethylene on its own or as
~: a mixture of at lea~t 70% by weight of ethylene and at
. ~ most 30% by weight of another 1-olefin of the above
. :
:;
~ ~$~
$~
: ~ .
~n~5z~
-- 7 --
formula.
It is especially preferred to polymerize ethylene on its
own or a mixture of at least 90% by weight of ethylene
and at most 10~ by weight of another l-olefin of the
above formula.
In known manner, ~he pol~meri%ation is ~arried out in
solutio~, in suspension or in the gas pha~ continuously
or batchwise, in ~ne or more steps, at a temperature of
20 to 200CJ preferably 50 to 150C. l~he pres~ure is 0.5
to 50 bar. The polymerization is preferably carried out
in the pressure range fro~ 5 ~o 30 bar, which is of par-
ticular interest in industry.
In this process, component a is used in a concentration,
based on titanium~ of O.OQOl to ~, preferably O.001 to
: 15 0.5, mmol of Ti per dm3 of di~persing medium or pex ~m3 of
reactor volume. ~he metal-orqanic c~mpound i~ used in a
concentration of 0.1 to 5 mmol, preferably O.S to 4 mmol,
per dm3 of dispersin~ medium or per dm3 of reactor volume.
In p:cinciple, however, higher concentrations are also
possible.
,
The ~uspension polymerization i~ carried ~ut in an inert
disper~ing medium conventionally used or the %iegler
low-pre~sure process I for example in an aliphatic or
cycloaliphatic hydrocarbon; butane, pentane, hexane,
heptane, isooctane, cyclohe~ane and methylcyclohexane may
be mentioned as examples of auch hydrocarbons. It is
also possible to usegasoline fractions or hydrogenated
diesel oil fractions from which oxygen~ sulfur compounds
and moi.sture have been carefully removed.
. ~
$he gas pha~e polymerization can be carried out direct or
after pxapolymerization of the catalyst in a suspension
process.
The molecular weight of the polymer is regulated in known
,:` ' '
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Z0~ 2~L
~ 8 --
manner, hydrogen preferably being used for thi~ purpose.
As a consequence of ~he high activity of the catalyst to
be used, the process according to the inventiQn gives
polymers with very low titanium and halogen contents and
hence excep~ionally good ~alues in the color fastness and
corrosion tests. Fur~hermore, said process makes it
possible to manufacture polymers with a ~ery broad
molecular weight distribution (polydispersity); the Mw/~
values of the polymers are o~er 10.
Another decisive advantage of the process a~cordin~ to
the invention can be seen in the fact that it makes it
possible to manufac~ure polymers with e~tremely different
molecular weights simply by varying the hydrogen con-
centrations. For example, polymers with molecular
weights of more than 2 million are ormed by polymeriza-
:~ tion without hydrogen and polymer6 with molecular weights
in the region of 30,000 ars formed by pol~merizatioll with
hydrogen contents of 70% by volume in ~he gas space.
The polymers can be processed by the extrusion and extru-
sion blowing processes to form hollow bodies, tubes,
; cables and films with smooth surface6, a~ high output
rates.
Becau~e they have a particular structure~ the hollow
bodies and bottles produced from the polyolefins obtained
according to the invention are di~tinguished by a high
insensitivity to stress crack formation.
~, ~
Furthermore, in the case of su5pen8ion and gas phase
polymerization, the proces~ according to the invention
: make~ it po~sible to manufacture free-flowing polymer
powders with high bulk densities, so further proces8ing
to form moldings can be carried out direct without a
j:~ granulation step.
, ~ Finally, in the proce~s according to the invention, the
,:;
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- 9 -
time spent on manufacture of the catalyst and the amount
of titani~m-containing hydrocarbon solutions obtained are
both reduced by 70%. Moreover, 12% of the expen6ive
titanium tetrachloride which has to be uæed in the con-
ventional process is saved.
The ~ollowing Examples are intended to illustra~e the
invention.
In the Examples, the manufacture of the catalyst and the
polymerization were carried out using a hydrogenated
diesel oil fraction with a boilin~ range of 130 to 170C.
The titanium content of the catalysts was determined by
colorimetry (liter~ture referencet G.O. Muiller,
"Praktikum der ~uantitativen chemischen Analyse"
("Laboratory manual of quant.itative chemical analy~
4th edition (1957) p. ~43).
The melt flow index, ~EI, was detenmined according to DIN
53 735 tE)-
The ~/M~ values were determined from the fractionationdata ef a gel p~rmeation chromatograph in o-dichloro-
benzene ~ODCB] as the solvent and eluent, at 13$C.
The viscosity number, VN, was determined accordlng to DIN
: 53 728 sheet 4 with an Ubbelohde vi~cometer in decahydro-
naphthalene a~ the ~olvent.
~ he den~ity was determined according to DI~ 53 479 and
~5 the bulk den~ity according ~o DIN 53 46~.
`' `
~ Example 1
3 ~ a) Preparation of com~onent a
?,~ In a 2 dm3 four-necke~ round-bottomed flask with a dropp-
~, ing funnel, stirrer, reflux condenser and thermometer,
:~ 30 114~3 g of magnesium ethylate wer~ dispersed in 1 dm3 of
:; - ` ~ :` ' , - ` ,
s~
-- 10 --
a diesel oil fraction under a blanket of N2. 332 g of
TiCl4 were added dropwise to this dispersion over 5.5 h.
After the 501id had settled, 0.5 dm3 of ~he supernatant
solution was wi~hdxawn at 60C and 1.1 dm3 of fresh
dispersing medium were added. After ~he volume had been
made up a total of follr ~imes with 1.1 dm3 of dispersing
: medium and a further 1.1 ~m3 of supernatant ~olution had
been withdrawn each time, the ~olume was made up with 0.5
dm3 of dispersing medium and the suspenKion wa~ stirred at
~ 10 125~C for 16 h. The supernatant solution then contained
: less than 10 mmol of Ti per dm3~ The ~olid (component a)
had the following analytical compoRitions
Ti 6.2~ by weight
Mg 70.8~ by weight
Cl 23.0~ by weight
b) Preacti~ation of component a
3~ g of component a were made up to 0.150 dm3 of ~uspen
sion with diesel oil a~d 36 cm3 of a 1 molar ~olution of
; triethylaluminum were added. The mixture wa~ ~tirred for
2 h at 120C, after which 85% of the titanium(IV) had
been reduced to titanium(III).
;
~ c) Polymeri~ation of ethylene in ~u~pen~ion
.,
0.75 dm3 of hydrocarbon, 5 mmol of aluminum isoprenyl and
0.8 mg of component a were placed in a 1.5 dm3 ~teel
autoclave. 3.2 bar Of ~2 and 3.9 bar of ethylene were
then introduced under pre~sure at a polymerization tem-
perature of 85C. Ethylene was subsequently metered in
80 as to maintaln the total pre~ure. The experiment was
discontlnued after 2 h. The polymer was separated off by
:~ 30 filtration and drie~ in a vacuum drying cabinetv 147 g
of pol~mqr were obtained. This corresponded to a
:; catalyst-time yield of 9.8 kg PE/mmol Ti h. ~he
~ polymer had a melt flow index ~FI 190/5 of 2.S g/10 min
; and a mel~ flow index ratio ~FI 190/21.6 to MFI 190/5 of
:
::
.: . , ,
,,: ' ,~ ~ , ,
2~
12.3. The ratio ~,/M~ from the GPC was 9.7.
~ample 2
100 dm3 of a diesel oil fraction, 50 mmol of aluminum
triethyl and 8 g of component a treated according to
S Example 1 b were placed in a 150 dm3 kettle. 0.~ m3 o
ethylene per h and the amount of Hz required to give an H2
concentration of 75% by volume were then introdu~ed at a
temperature of 85C. 0.2 dm3 of but~ ene was me~ered in
at the ~ame time. After 2.5 h, the polymerization wa8
~topped a~ a pressure of 8 bar ~y relea~ing the pressure.
In a second stage of the reactionr 0.7 m3 ethylene/h and
the amount of H2 required to ~ive an ~2 cQncentratiOn of
2~ were introduced. 1 dm3 of but-lcene wa~ metered in at
the same time. The polymerization wa~ di~continued after
3 h. The suspension was filtered and the polymer was
dried by having hot nitroyen pa~sed over it. 31 kg o~
~; product were obtained.
:. ~
~he polyethylene powder had a ~N o~ 290 cm3/g. ~he den-
~; ~ity was 0.945 g~cm3. At an MFI 190~5 of 0.6 y/10 min,
: 20 the ratio MFI 190/21.6 to MFI 190/5 was 22.
ple 3
~' .
Component a was prepared as in Example 1 a and the sus
~: pendin~ medium was remo~ed. Thi~ ~olid, which wa~ ~table
~; on storage, was ~uspended in a hydrocarbon and treated as
~, ~ 25 in Example 1 b. Polymeri~a~ion as described in Example
1 ~ ga~e 149 g of polymer. ~hi~ corre~ponded to a
:1 cataly~t-time yield of 9.9 kg PE/mmol Ti.h. The polymer
: . had a melt flow index MFI 190/5 of 5.2 g/10 min an~ a
:~ melt flow index ratio M~I 190/21.6 to MFI 190/5 of 11Ø
,,,
Comparative E~ample
~J. ' In a 2 dm3 four-necked round-bottomed fla~k with a drop-
:,~ ping funnel, stirrer, reflux condenser and thermometer,
.. .
~~ .
., ~ ~ : . - : .
s~
114.3 g of magnesium ethylate were dispersed in 1 dm3 of
a diesel oil fraction und~r a blanket of N2. 332 g of
TiC14 were added drop~ise to this dispersion o~er 5.5 h.
The suspending medium was repeatedly changed until the
liquid phase no longer contained titanium. 6 cm3 of TiC14
were added and the suspension was stirred at 125C. ~he
Ti concentration in the liquid phase wa~ 28 mmol/dm3 after
18 h, 27 mmol/dm3 after a further 4 h and ~till 24
mmol/dm3 after tempering for a total of 60 hours. The
solid was washed once more wi~h a h~drocarbon and then
pretreated and polymerized as described in Example 1.
Analytical composition of the catalyst:
~i 5.3~ by weight
Mg 23.5% by weigh~
Cl 71.2~ by weigh~
160 g of polyethylene were obtained ~rom the polymeri2a-
tion. The polymer had an MFI 190/5 of 3.1 g/10 min and
a melt flow index ratio ~FI l90/21.6 to MFI 190~5 of 11,
Example 4
lO0 dm3 of a diesel oil fraction, 40 mmol of aluminum
triethyl and 1.2 g of component a treated according to
Example 1 b were placed in a 150 dm3 kektle. 6.4 kg
ethylene/h and the amount of H2 required to gi~e a con-
centration of 36% by ~olume were then introduced at a
temperature of 85C. After 4 h, the pol~merization was
~topped at a pressure of 6.6 ~ar by relea~ing the pres-
sure. The suspen~ion was filtered and the pol~mer was
drie~ by having hot nitrogen passed over it. 25.5 kg of
product were obtained, corre~ponding to a catalys~ yield
of 21 kg/g cataly~t. The polymer had an MFI 190/5 of 0.8
; g/10 min and a ratio MFI l90/21.6 to MFI l90/5 of 13.
,~
.
. ~ .
;
~ .
85Z~
- 13 -
Example~ 5 to 7
The copolymerization result~ obtained analogously to
Example 4 with butene, propene and hexene as comonomers
are listed in Table 1.
Table 1: Copolymer~
Polymeriza- Yield MFI 190~5 MYI 190~21.6
; tion tLme to MFI 190/5
h kg g/10 min
Ex. 5 170 cm3 of
but-l-ene 4 25O3 1.3 15
Ex. 6 260 cm3 Of
propene 3.7523.6 1.7 17
. .
Ex. 7 620 cm3 Of
h~x-l-ene 3.824.3 1.1 12
.
~,
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