U.S. patent application number 09/970780 was filed with the patent office on 2002-03-07 for carrier for olefin polymerization catalysts.
Invention is credited to Hafner, Norbert, Luciani, Luciano, Neibl, Wolfgang.
Application Number | 20020028743 09/970780 |
Document ID | / |
Family ID | 8226483 |
Filed Date | 2002-03-07 |
United States Patent
Application |
20020028743 |
Kind Code |
A1 |
Luciani, Luciano ; et
al. |
March 7, 2002 |
Carrier for olefin polymerization catalysts
Abstract
Procedure for the preparation of a solid carrier for olefin
polymerization catalysts comprising the steps: a) impregnating a
silica with a solution of Mg-chloride in the presence of electron
donors, b) drying the impregnated silica obtained in (a) and
impregnating it with a solution of Mg-alkyls in SiCl.sub.4 at a
temperature from -10 to 20.degree. C., optionally adding a further.
amount of electron donors, c) subsequently treating the slurry
obtained in (b) at a temperature from 40.degree. C. to reflux
temperature, d) drying the carrier obtained in (c). The carrier
which is obtained according to the above procedure is
advantageously used for the preparation of supported catalysts for
the polymerization of olefins
Inventors: |
Luciani, Luciano; (Ferrara,
IT) ; Neibl, Wolfgang; (Lichtenberg, AT) ;
Hafner, Norbert; (Linz, AT) |
Correspondence
Address: |
WENDEROTH, LIND & PONACK, L.L.P.
2033 K STREET N. W.
SUITE 800
WASHINGTON
DC
20006-1021
US
|
Family ID: |
8226483 |
Appl. No.: |
09/970780 |
Filed: |
October 5, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09970780 |
Oct 5, 2001 |
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09543788 |
Apr 6, 2000 |
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09543788 |
Apr 6, 2000 |
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09023772 |
Feb 13, 1998 |
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6096681 |
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Current U.S.
Class: |
502/152 ;
502/251; 585/511 |
Current CPC
Class: |
C08F 110/06 20130101;
C08F 110/06 20130101; C08F 4/025 20130101; C08F 10/00 20130101;
C08F 2500/12 20130101; C08F 4/025 20130101; C08F 2500/15 20130101;
C08F 10/00 20130101; C08F 2500/18 20130101 |
Class at
Publication: |
502/152 ;
502/251; 585/511 |
International
Class: |
B01J 021/08; C07C
002/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 1997 |
EP |
97102500.2 |
Claims
1. Procedure for the preparation of a solid carrier for olefin
polymerization catalysts, comprising the steps: a) impregnating a
silica with a solution of Mg-chloride in the presence of electron
donors, b) drying the impregnated silica obtained in (a) and
impregnating it with a solution of Mg-alkyls in SiCl.sub.4 at a
temperature from -10 to 20.degree. C., optionally adding a further
amount of electron donors, c) subsequently treating the slurry
cotained in (b) at a temperature from 40.degree. C. to reflux
temperature. d) drying the carrier obtained in (c).
2. Procedure according to claim 1, wherein an ester is used as a
solvent for Mg-chloride.
3. Procedure according to claim 2, wherein the solvent for
Mg-chloride is ethyl formiate, ethyl acetate, ethyl propionate,
isopropyl acetate or isopropyl propionate
4. Procedure according to any of claims 1 to 3, wherein the silica
obtained after the impregnation step (a) contains less than 6% wt
of Mg, referred to the final carrier.
5. Procedure according to any of claims 1 to 4, wherein the carrier
obtained in step (d) contains 2 to 10% wt, preferably 5 to 8% wt of
Mg, referred to the final carrier.
6. Procedure according to any of claims 1 to 5, wherein the silica
has a content of OH-groups of 0 to 5 mM/g.
7. Procedure according to any of claims 1 to 6, wherein the silica
is spheroidal and porous without a content of free water, and
having an average particle size of 15 to 150 micron, a surface area
of 100 to 500 m.sup.2/g, a pore volume of 1.2 to 3 ml/g and an
average pore diameter of 20 to 500 angstrom.
8. Procedure according to any of claims 1 to 7, wherein the molar
ratio of Mg-alkyl: SiCl.sub.4 is from 1:5 to 1:30.
9. Procedure according to any of claims 1 to 8, wherein phthalic
acid esters are used as donors.
10. Procedure according to claim 9, wherein diisobutylphthalate is
used as the donor
11. Procedure according to any of claims 1 to 10, wherein the donor
is used in an amount of 20 to 100% wt, referred to the silica.
12. Procedure according to any of claims 1 to 11, wherein the
Mg-alkyl is a Mg-diethyl, Mg-ethylbutyl, Mg-dihexyl or
Mg-butyloctyl.
13. Procedure for the preparation of a supported catalyst for the
polymerization of .alpha.-olefins. wherein a carrier (or support)
obtained according to any of claims 1 to 12, is contacted with a
transition metal halide of group IVb, Vb or VIb of the periodic
table, and optionally with electron donors.
14. Process for the preparation of polyolefins by
homopolymerization or copolymerization of olefins, wherein a
supported catalyst according to claim 13 is used.
Description
[0001] The present invention relates to a procedure for producing a
carrier (or support) to be used for the preparation of catalysts
for polymerizing .alpha.-olefins alone or in mixture.
[0002] .alpha.-olefins such as ethylene, propylene and higher
olefin monomers can be polymerized by using Ziegler-Natta-catalysts
based on a combination of organometallic compounds of elements of
groups IA to IIIA and a compound of a transition metal belonging to
groups IVB to VIB of the periodic table (e.g. in Boor Jr,
Ziegler-Natta-Catalysts and Polymerization, Academic Press, New
York. 1979).
[0003] To improve the morphology of the resin, it is moreover known
to impregnate a granular solid of microspheroidal carrier with the
catalyst (Karol F J Cat. Rev. Sci. Eng 26, 384, 557-595, 1984)
Among others. silica can be used as a catalyst carrier for
.alpha.-olefin polymerization
[0004] It is important to use an appropriate selective carrier for
the preparation of .alpha. olefin catalyst preparation which can be
impregnated with the active part of the catalysts, thereby
enhancing the properties.
[0005] Various proposals have been made in the art for preparing a
carrier and subsequently a catalyst for olefin polymerization. From
EP-application 96118559, a catalyst for the polymerization of
olefins is known, which is prepared by impregnating a silica with a
Mg-halide and a Mg-alkyl, halogenating and then impregnating with a
Ti-tetrahalide.
[0006] According to U.S. Pat. No. 5,310,716, a non preactivated
silica (containing hydroxyl groups and water) is treated with
Mg-alkyl and then (after removing the liquid, washing and drying)
with tetrachlorosilane, whereby a carrier is obtained. After this
step, a treatment with an excess of Ti-tetrachloride and donor is
carried out.
[0007] According to U.S. Pat. No. 5,006,620 a silica is treated
with Mg-alkyl, then with chlorine or hydrochloric acid and with a
C.sub.1-8-alkanol for attaining a carrier, which is subsequently
treated with an excess of Ti-tetrachloride and donor for achieving
a catalyst.
[0008] According to U.S. Pat. No. 4,639,430, a silica is
impregnated with Mg-chloride (dissolved in water), dried, mixed
with NH.sub.4Cl and treated at high temperature. whereby a carrier
with a minimum content of hydroxyl groups is obtained. This support
is then impregnated with heptane, containing a very small amount of
Ti-tetrachloride for attaining a catalyst for the preparation of
polyethylene or for ethylene-propylene rubbers.
[0009] In the field of catalyst research it is still strongly
desirable to find new catalyst components or catalyst systems with
improved performance, especially with high activity and/or high
stereoregularity.
[0010] According to the present invention. it has now been found
that a silica, which does not contain free water, but different
amounts of hydroxylgroups, can be treated with a solution of
Mg-chloride in the presence of electron donors and with a solution
of Mg-alkyls dissolved in Si-tetrachloride at low temperature and
subsequently heating to reflux temperature, whereby Mg-chloride is
precipitated.
[0011] The present invention accordingly provides a procedure for
the preparation of a solid carrier for olefin polymerization
catalysts, comprising the steps:
[0012] a) impregnating a silica with a solution of Mg-chloride in
the presence of electron donors,
[0013] b) drying the impregnated silica obtained in (a) and
impregnating it with a solution of Mg-alkyls in SiCl.sub.4 at a
temperature from -10 to 20.degree. C., optionally adding a further
amount of electron donors,
[0014] c) subsequently treating the slurry obtained in (b) at a
temperature from 40.degree. C. to reflux temperature,
[0015] d) drying the carrier obtained in (c).
[0016] We have moreover found that by treating this carrier (or
support) with Ti-tetrachloride or a mixture of Ti-tetrachloride and
Ti-alkoxide, highly active catalysts for stereoregular
polypropylenes and for polyethylene, including their copolymers,
are obtained.
[0017] The silica suitable for the support is preferably a
spheroidal, porous silica with a particle size of 15 to 150 micron.
with a surface area of 100 to 500 m.sup.2/g, a pore volume of 1.2
to 3 ml/g and an average pore diameter of 20 to 500 angstrom. The
silica has preferably a content of hydroxyl groups of 0 to 5
mmol/g, most preferred of 0.1 to 3 mmol/g.
[0018] The preferred solvent for Mg-chloride is an ester like e.g.
ethyl formiate, ethyl acetate, ethyl propionate. isopropyl acetate,
isopropyl propionate or ethyl carbonate. Preferred esters are ethyl
formiate, ethyl acetate, ethyl propionate, isopropyl acetate,
isopropyl propionate.
[0019] According to the invention, it is further preferred that the
silica obtained after the impregnation step (a) contains less than
6% wt of Mg, referred to the final carrier, and that the carrier
obtained in step (d) contains 2 to 10% wt, preferably 5 to 8% wt of
Mg, referred to the final carrier.
[0020] In step (a) of the invention, the silica is directly
impregnated with Mg-chloride, whereas an additional amount of
Mg-chloride is brought into the silica by the reaction of Mg-alkyl
and SiCl.sub.4, which are added in step (b) and which react mainly
at the higher temperature in step (c). whereby said additional
Mg-chloride is precipitated. The weight ratio of Mg-chloride from
step (a): Mg-chloride from steps (b/c) is preferably in the range
of 0.1:1 to 10:1, more preferred between 0.2:1 to 5:1 and most
preferred between 0.5:1 to 2:1.
[0021] Further preferred is a molar ratio of Mg-alkyl: SiCl.sub.4
from 1:5 to 1:30
[0022] Phthalic acid esters are preferred as donors, whereby the
most preferred donor is diisobutylphthalate (DIBP). The donors are
preferably used in an amount of 20 to 100% wt, referred to the
silica, but it is also possible to use higher amounts of
donors.
[0023] The Mg-alkyls used in step (b) are preferably Mg-alkyls with
1 to 10 C-atoms in the alkyl group. Most preferred are Mg-diethyl,
Mg-ethylbutyl, Mg-dihexyl and Mg-butyloctyl.
[0024] According to the present invention, the procedure will
preferably comprise the following steps:
[0025] In the first step of the invention, the silica is suspended
in a solution of Mg-chloride in ethylacetate (EA) in the presence
of DIBP, the amount of DIBP being 20 to 100% wt. preferably 60% wt,
referred to the silica. The impregnation of the silica with
Mg-chloride dissolved in EA can be carried out in one or more steps
Ethylformiate, ethylpropionate, isopropylacetate or
isopropylpropionate can also be used as a solvent. The amount of Mg
to be impregnated in the form of Mg-chloride is 1 to 6% wt,
preferably 4% wt, referred to the final carrier.
[0026] The above slurry is then heated for 2 h at reflux under
stirring, and then EA is distilled off.
[0027] The dried carrier is subsequently submitted to another
impregnation step, using a solution of Mg-alkyl in
Si-tetrachloride. As Mg-alkyl, Mg-diethyl, Mg-ethylbutyl,
Mg-butyloctyl or Mg-dihexyl may be used. The amount of Mg to be
impregnated in this step in the form of e.g. Mg-dihexyl, which is
then converted to Mg-chloride at higher temperatures, is 1 to 9%
wt, preferably 1 to 4% wt, referred to the final carrier.
[0028] After 2 h stirring at about 0.degree. C., the temperature is
increased to reflux and maintained for 2 h at this value, whereby
Mg-chloride is precipitated in disordered active form into the
pores of the silica. At this step the diluent is removed and after
drying the carrier is ready to be used for catalyst
preparation.
[0029] The invention further concerns a procedure for the
preparation of a supported catalyst for the polymerization of
.alpha.-olefins, wherein a carrier (or support) obtained according
to the invention, is contacted with a transition metal halide of
group IVb, Vb or VIb of the periodic table, and optionally with
electron donors Preferably Ti-tetrachloride is used as the
transition metal halide, optionally in the presence of a
Ti-alkoxyde. The Ti-tetrachloride may be used undiluted or as a
solution in organic solvents, e.g. in toluene or ethylbenzene.
[0030] The supported catalyst as described above can be
advantageously used in bulk, slurry or gas phase processes for the
preparation of polyolefins by homopolymerization or
copolymerization with two or more monomers The catalyst can be used
also in the polymerization of ethylene as it is or omitting
internal and external donors.
[0031] The present invention further relates to a process for the
preparation of polyolefins by homopolymerization or
copolymerization of olefins, wherein a supported catalyst as
described above is used. The polymerization is conducted according
to conventional methods, operating in a liquid phase, either in the
presence or in the absence of an inert hydrocarbon diluent, or in
gas phase.
[0032] The catalyst of the invention can be used also at higher
temperatures, whereby the polymerization is preferably carried out
at a temperature of about 20.degree. to 150.degree. C., more
preferred between 70.degree. C. and 120.degree. C. at atmospheric
pressure or at a higher pressure. in absence or in presence of
hydrogen
[0033] The catalyst of the present invention shows an improved
performance. and is also permitting to achieve very low values of
extractable amorphous resins in boiling n-heptane and xylene.
[0034] Many other .alpha.-olefins can also be polymerized using
this catalyst, like butene-1, 4-methyl-1-pentene hexene-1, alone or
in mixture with other .alpha.-olefins for obtaining copolymers and
terpolymers, mainly of rubber type.
[0035] The use of this catalyst permits moreover to obtain
controlled polymer particle size of the desired dimension on the
basis of the choice of the selected silica.
EXAMPLE 1
[0036] Carrier Preparation
[0037] 20 g microspheroidal silica, treated at 740.degree. C.
(resulting in 1,12 mmol/g of OH-groups), with a surface area of
150-300 m.sup.2/g, pore volume of 1.58 ml/g and an average particle
sice of 75 micron, are charged in nitrogen atmosphere into a 500 ml
flask. equipped with a reflux cooler, stirrer and thermometer,
containing a solution of 4.5 Mg-chloride dissolved in 300 ml
ethylacetate and 10 ml diisobutylphthalate. The slurry is treated
at reflux for 2 h under stirring and then distilled at 90.degree.
C. without vacuum. Then the resulting white powder is dried under
vacuum at 90.degree. C for 1 h. This powder is added under nitrogen
to a solution of 20 g Mg-(hexyl)2 (diluted in a hydrocarbon: 20% wt
in heptane) in 100 ml Si-tetrachloride at 2.degree. C. and stirred
for 2 h.
[0038] Then the temperature is increased to the reflux. and the
slurry is stirred for 2 h to precipitate Mg-chloride in disordered
active form After adding 10 ml diisobutylphthalate and 20 ml
n-heptane, stirring was continued for 1 h at reflux After washing
with 300 ml n-heptane for two times and with 300 ml n-pentane for
two times (all washings at room temperature) and drying, the
carrier is ready to be used to prepare a catalyst usable for
polymerization or copolymerization of ethylene. propylene and other
alpha-olefines.
[0039] Catalyst Preparation:
[0040] The carrier, obtained as described, is treated at
110.degree. C. with 120 ml Ti-tetrachloride for 1.5 h. After
filtering at 110.degree. C., the treatment with Ti-tetrachloride at
110.degree. C. is carried out again twice. After final-filtration
at 110.degree. C., the solid material is washed 5 times with 300 ml
of n-heptane at 95.degree. C for 0,5 h each time. After two washing
treatments with 300 ml n-pentane at room temperature, the catalyst
is dried. 53.08 g of a brown powder were obtained, containing 4.05%
wt Ti, 5,49% wt Mg and 31.8% wt Cl.
[0041] Polymerization:
[0042] The activity and stereospecifity of this solid catalyst
component were determined in runs of propylene polymerization in
liquid monomer, using aluminiumtrialkyls treated with
electron-donor compounds as a cocatalyst:
[0043] A 5 l-autoclave equipped with a magnetic stirrer was filled
with 1327 g propylene and 10 l H.sub.2, which was used as a
molecular weight modifier.
[0044] About 24 mg of solid catalyst component were mixed with a
complex of triethylaluminium/dicyclopentyldimethoxysilane (20:1
mol/mol) in a ratio of 100:1 (mol Al/mol. Ti) and introduced into
the autoclave. After heating to 70.degree. C. the polymerization
was running for two hours and then the remaining propylene was
flashed off. The polymer was stabilized and dried at 50.degree. C.
under vacuum.
[0045] A yield equal to 12.9 kg PP per g of solid catalyst
component and equal to 319 kg PP per g of Ti was achieved with the
following characteristics
1 MFI (2.16 kg; 230.degree. C. ASTM D 1238 L) = 7.4 Bulk density
(g/ml) = 0.423 Isotactic index (%) = 98.0 Xylene cold solubles (%
wt) = 0.98
* * * * *