U.S. patent application number 08/927059 was filed with the patent office on 2001-09-20 for components and catalysts for the polymerization of olefins.
Invention is credited to GOVONI, GABRIELE, PASQUALI, STEFANO, SACCHETTI, MARIO.
Application Number | 20010023231 08/927059 |
Document ID | / |
Family ID | 23790419 |
Filed Date | 2001-09-20 |
United States Patent
Application |
20010023231 |
Kind Code |
A1 |
SACCHETTI, MARIO ; et
al. |
September 20, 2001 |
COMPONENTS AND CATALYSTS FOR THE POLYMERIZATION OF OLEFINS
Abstract
The present invention relates to components of catalysts for the
polymerization of olefins comprising a metallocene compound and a
magnesium halide which have particular values of porosity and
surface area. In particular the components of the invention have
surface area (BET) greater than about 50 m.sup.2/g, porosity (BET)
greater than about 0.15 cm.sup.3/g and porosity (Hg) greater than
0.3 cm.sup.3/g, with the proviso that when the surface area is less
than about 150 m.sup.2/g, the porosity (Hg) is less than about 1.5
cm.sup.3/g. The components of the invention are particularly
suitable for the preparation of catalysts for the gas-phase
polymerization of .alpha.-olefins.
Inventors: |
SACCHETTI, MARIO; (FERRARA,
IT) ; PASQUALI, STEFANO; (FOSSANOVA SAN MARCO,
IT) ; GOVONI, GABRIELE; (RENAZZO, IT) |
Correspondence
Address: |
WARREN K.MacRae
BRYAN CAVE LLP
245 PARK AVENUE
NEW YORK
NY
10167-0034
US
|
Family ID: |
23790419 |
Appl. No.: |
08/927059 |
Filed: |
September 10, 1997 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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08927059 |
Sep 10, 1997 |
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08451008 |
May 25, 1995 |
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5698487 |
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Current U.S.
Class: |
502/117 ;
502/118; 502/119; 502/120; 502/125; 502/126 |
Current CPC
Class: |
C08F 210/08 20130101;
B01J 35/10 20130101; B01J 2531/48 20130101; B01J 2531/49 20130101;
C08F 2500/12 20130101; C08F 4/65916 20130101; C08F 2500/17
20130101; B01J 2531/56 20130101; C08F 2500/08 20130101; B01J
2531/46 20130101; B01J 31/1616 20130101; B01J 31/2295 20130101;
B01J 35/1042 20130101; B01J 35/1019 20130101; B01J 31/143 20130101;
C08F 4/65912 20130101; B01J 35/023 20130101; C08F 210/16 20130101;
C08F 10/00 20130101; B01J 35/1014 20130101; B01J 31/26 20130101;
C08F 210/16 20130101; C08F 10/00 20130101; B01J 35/108 20130101;
C08F 4/65927 20130101 |
Class at
Publication: |
502/117 ;
502/118; 502/119; 502/120; 502/125; 502/126 |
International
Class: |
C08F 004/02; C08F
004/60; B01J 031/00; B01J 037/00 |
Claims
1. A component of catalysts for the polymerization of olefins
comprising a compound of a transition metal M selected among Ti, V,
Zr and Hf containing at least one M-.pi. bond, and a halide of Mg,
characterized by surface area (BET) greater than about 50
m.sup.2/g, porosity (BET) greater than 0.15 cm.sup.3/g and porosity
(Hg) greater than 0.3 cm.sup.3/g, with the proviso that when the
surface area is less than about 150 m.sup.2/g, the porosity (Hg) is
less than about 1.5 cm.sup.3/g.
2. A component according to claim 1, having surface area greater
than 150 m.sup.2/g and porosity (BET) greater than 0.2
cm.sup.3/g.
3. A component according to claim 1, having surface area less than
150 m.sup.2/g and porosity (Hg) between 0.5 and 1.2 cm.sup.3/g.
4. A component according to claim 1, wherein more than 40% of the
porosity (BET) is due to pores with radius greater than 300
.ANG..
5. A component according to claim 1, wherein more than 50% of the
porosity (BET) is due to pores with radius between 600 .ANG. and
1000 .ANG..
6. A component according to claim 1 in the form of spheroidal
particles with size smaller than 150 microns.
7. A component according to claim 1 obtained by supporting a
compound of a transition metal M selected from Ti, V, Zr and Hf
containing at least one M-.pi. bond, on a halide of Mg or on a
support containing a halide of Mg that has surface area between 200
and 800 m.sup.2/g and porosity (BET) greater than 0.3 cm.sup.3/g
and porosity (Hg) greater than 0.3 cm.sup.3/g.
8. A component according to claim 7, wherein the halide of Mg is in
the form of spheroidal particles with size smaller than 150
microns.
9. A component according to claim 7, wherein the halide of Mg is
supported on an inert support selected from silica, alumina,
silica-alumina possessing surface area between 300 and 600
m.sup.2/g and porosity (BET) greater than 0.5 cm.sup.3/g and
partially crosslinked polystyrene with surface area between 100 and
500 m.sup.2/g and porosity (BET) greater than 0.5 cm.sup.3/g.
10. A component according to claim 8, wherein the halide of Mg is
obtained from spherulized MgX.sub.2.alcohol adducts that are then
reacted with an alkyl-Al compound to remove the alcohol.
11. A component according to claim 10, wherein the Mg halide is Mg
chloride obtained from MgCl.sub.2.3ROH adducts, in which R is an
alkyl radical with 1-8 carbon atoms, which are submitted to partial
dealcoholizing and then reacted with the alkyl-Al compound.
12. A component according to claim 1, wherein the transition metal
compound contains at least one ligand L coordinated on the metal M,
which has a mono- or polycyclic structure containing conjugated
.pi. electrons.
13. A component according to claim 12, wherein the transition metal
compound is selected from compounds having the structure:
Cp.sup.IMR.sup.1.sub.aR.sup.2.sub.bR.sup.3.sub.c (I)
Cp.sup.I1Cp.sup.IIMR.sup.1.sub.aR.sup.2.sub.b (II)
(Cp.sup.I--A.sub.c--Cp.sup.II)MR.sup.1.sub.aR.sup.2.sub.b (III) in
which M is Ti, V, Zr or Hf; CpI and Cp.sup.II, identical or
different, are cyclopentadienyl groups, including substituted ones;
two or more substituents on the said cyclopentadienyl groups can
form one or more rings possessing from 4 to 6 carbon atoms;
R.sup.1, R.sup.2 and R.sup.3, identical or different, are atoms of
hydrogen, halogen, an alkyl or alkoxyl group with 1-20 carbon
atoms, aryl, alkaryl or aralkyl with 6-20 carbon atoms, an acyloxy
group with 1-20 carbon atoms, an allyl group, a substituent
containing a silicon atom; A is an alkenyl bridge or one with
structure selected from: 2.dbd.AlR.sub.1, --Ge--, --Sn--, --O--,
--S--, .dbd.SO, .dbd.SO.sub.2, .dbd.NR.sub.1, .dbd.PR.sub.1,
.dbd.P(O)R.sub.1, in which M.sub.1 is Si, Ge, or Sn; R.sub.1 and
R.sub.2, identical or different, are alkyl groups with 1-4 carbon
atoms or aryl groups with 6-10 carbon atoms; a, b, c are,
independently, integers from 0 to 4; e is an integer from 0 to 6
and two or more of the radicals R.sup.1, R.sup.2 and R.sup.3 can
form a ring.
14. A component according to claim 12, wherein the transition metal
compound is selected from compounds that have the structure:
(Me.sub.5Cp)MMe.sub.3, (Me.sub.5Cp)M(OMe).sub.3,
(Me.sub.5Cp)MCl.sub.3, (Cp)MCl.sub.3, (Cp)MMe.sub.3,
(MeCp)MMe.sub.3, (Me.sub.3Cp)MMe.sub.3, (Me.sub.4Cp)MCl.sub.3,
(Ind)MBenz.sub.3, (H.sub.4Ind)MBenz.sub.3, (Cp)MBu.sub.3.
15. A component according to claim 12, wherein the transition metal
compound is selected from compounds that have the structure:
(Cp).sub.2MMe.sub.2, (Cp).sub.2MPh.sub.2, (Cp).sub.2MEt.sub.2,
(Cp).sub.2MCl.sub.2, (Cp).sub.2M(OMe).sub.2, (Cp).sub.2M(OMe)Cl,
(MeCp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2MCl.sub.2,
(Me.sub.5Cp).sub.2MMe.sub.2, (Me.sub.5Cp).sub.2MMeCl,
(Cp)(Me.sub.5Cp)MCl.sub.2, (1-MeFlu).sub.2MCl.sub.2,
(BuCp).sub.2MCl.sub.2, (Me.sub.3Cp).sub.2MCl.sub.2,
(Me.sub.4Cp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2M(OMe).sub.2,
(Me.sub.5Cp).sub.2M(OH)Cl, (Me.sub.5Cp).sub.2M(OH).sub.2,
(Me.sub.5Cp).sub.2M(C.sub.6H.sub.5).sub.2,
(Me.sub.5Cp).sub.2M(CH.sub.3)C- l, (EtMe.sub.4Cp).sub.2MCl.sub.2,
[(C.sub.6H.sub.5)Me.sub.4Cp].sub.2MCl.su- b.2,
(Et.sub.5Cp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2M(C.sub.6H.sub.5)Cl,
(Ind).sub.2MCl.sub.2, (Ind).sub.2MMe.sub.2,
(H.sub.4Ind).sub.2MCl.sub.2, (H.sub.4Ind).sub.2MMe.sub.2,
{[Si(CH.sub.3).sub.3]Cp}.sub.2MCl.sub.2,
{[Si(CH.sub.3).sub.3].sub.2Cp}.sub.2MCl.sub.2,
(Me.sub.4Cp)(Me.sub.5Cp)MC- l.sub.2.
16. A component according to claim 12, wherein the transition metal
compound is selected from compounds that have the structure:
C.sub.2H.sub.4(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(Ind).sub.2MMe.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub- .2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MMe.sub.2, Me.sub.2SiCp.sub.2MCl.sub.2,
Me.sub.2SiCp.sub.2MMe.sub.2, Me.sub.2Si(Me.sub.4Cp).sub.2MMeOMe,
Me.sub.2Si(Flu).sub.2MCl.sub.2,
Me.sub.2Si(2-Et-5-iPrCp).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Ind).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Flu).sub.2MCl.su- b.2,
Me.sub.2SiCH.sub.2(Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-H.sub.4Ind).s- ub.2MCl.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2, Me.sub.2Si(2-Et-5-iPr-C-
p).sub.2MCl.sub.2, Me.sub.2Si(2-Me-5-EtCp).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-5-Me-Cp).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-4,5-benzoindenyl- ).sub.2MCl.sub.2,
Me.sub.2Si(4,5-benzoindenyl).sub.2MCl.sub.2,
Me.sub.2Si(2-EtInd).sub.2MCl.sub.2,
Me.sub.2Si(2-iPr-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-t-butyl-Ind)MCl.sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MCl- .sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MMe.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-4,5-benzoindenyl)- .sub.2MCl.sub.2,
Me.sub.2C(Flu)CpMCl.sub.2, Ph.sub.2Si(Ind).sub.2MCl.sub.2- ,
Ph(Me)Si(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind)M(NMe.sub.2)OMe,
isopropylidene-(3-t-butyl-Cp)(Flu)MCl.sub.2,
Me.sub.2C(Me.sub.4Cp)(MeCp)M- Cl.sub.2, MeSi(Ind).sub.2MCl.sub.2,
Me.sub.2Si(Ind).sub.2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl(OEt),
C.sub.2H.sub.4(Ind).sub.2M(NMe.sub.- 2).sub.2,
C.sub.2H.sub.4(Me.sub.4Cp).sub.2MCl.sub.2,
C.sub.2Me.sub.4(Ind).sub.2MCl.sub.2,
Me.sub.2Si(3-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3-Me-Ind).sub.2MC- l.sub.2,
C.sub.2H.sub.4(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.- sub.3Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3,4,7-Me.sub.3Ind).sub.2MCl.sub.2- ,
C.sub.2H.sub.4(2-Me-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(4,7-Me.su- b.2-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.sub.3-H.sub.4Ind).- sub.2MCl.sub.2,
Me.sub.2Si(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2,4,7-Me.sub.3-H.- sub.4Ind).sub.2MCl.sub.2.
17. A component according to claim 1, wherein the transition metal
compound is present in a quantity of from 0.1 to 5% by weight
expressed as metal.
18. A catalyst for the polymerization of olefins comprising the
product of the reaction of a component according to claim 1 with an
alkyl-Al compound selected from trialkyl-Al's in which the alkyl
groups have from 1 to 12 carbon atoms and linear or cyclic
alumoxane compounds containing the repeating unit --(R.sub.4)AlO--,
in which R.sub.4 is an alkyl group with 1-6 carbon atoms or a
cycloalkyl or aryl group with 6-10 carbon atoms and containing from
2 to 50 repeating units.
19. A catalyst according to claim 18, wherein the alkyl-Al compound
is a mixture of trialkyl-Al and an alumoxane.
20. A catalyst according to claim 18 or 19, wherein the alumoxane
is polymethyl-alumoxane.
21. A catalyst according to claim 18 or 19, wherein the trialkyl-Al
compound is reacted with 0.5-0.01 mol of water per mole of
trialkyl-Al and in which the compound of transition metal M is
selected from: C.sub.2H.sub.4(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(Ind).sub.2MMe.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub- .2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MMe.sub.2, Me.sub.2SiCp.sub.2MCl.sub.2,
Me.sub.2SiCp.sub.2MMe.sub.2, Me.sub.2Si(Me.sub.4Cp).sub.2MMeOMe,
Me.sub.2Si(Flu).sub.2MCl.sub.2,
Me.sub.2Si(2-Et-5-iPrCp).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Ind).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Flu).sub.2MCl.su- b.2,
Me.sub.2SiCH.sub.2(Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-H.sub.4Ind).s- ub.2MCl.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2, Me.sub.2Si(2-Et-5-iPr-C-
p).sub.2MCl.sub.2, Me.sub.2Si(2-Me-5-EtCp).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-5-Me-Cp).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-4,5-benzoindenyl- ).sub.2MCl.sub.2,
Me.sub.2Si(4,5-benzoindenyl).sub.2MCl.sub.2,
Me.sub.2Si(2-EtInd).sub.2MCl.sub.2,
Me.sub.2Si(2-iPr-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-t-butyl-Ind)MCl.sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MCl- .sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MMe.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-4,5-benzoindenyl)- .sub.2MCl.sub.2,
Me.sub.2C(Flu)CpMCl.sub.2, Ph.sub.2Si(Ind).sub.2MCl.sub.2- ,
Ph(Me)Si(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind)M(NMe.sub.2)OMe,
isopropylidene-(3-t-butylCp)(Flu)MCl.sub.2,
Me.sub.2C(Me.sub.4Cp)(MeCp)MC- l.sub.2, MeSi(Ind).sub.2MCl.sub.2,
Me.sub.2Si(Ind).sub.2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl(OEt),
C.sub.2H.sub.4(Ind).sub.2M(NMe.sub.- 2).sub.2,
C.sub.2H.sub.4(Me.sub.4Cp).sub.2MCl.sub.2,
C.sub.2Me.sub.4(Ind).sub.2MCl.sub.2,
Me.sub.2Si(3-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3-Me-Ind).sub.2MC- l.sub.2,
C.sub.2H.sub.4(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.- sub.3Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3,4,7-Me.sub.3Ind).sub.2MCl.sub.2- ,
C.sub.2H.sub.4(2-Me-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(4,7-Me.su- b.2-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.sub.3-H.sub.4Ind).- sub.2MCl.sub.2,
Me.sub.2Si(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2,4,7-Me.sub.3-H.- sub.4Ind).sub.2MCl.sub.2.
22. A process for the polymerization of olefins CH.sub.2.dbd.CHR in
which R is hydrogen or an alkyl, cycloalkyl or aryl radical with
1-10 carbon atoms or an aryl in which a catalyst according to claim
18 is used.
23. A process for the polymerization of olefins CH.sub.2.dbd.CHR in
which R is an alkyl, cycloalkyl or aryl radical with 1-10 carbon
atoms in which the catalyst used is obtained from a component
according to claim 16.
24. A process for the polymerization of ethylene and of its
mixtures with CH.sub.2.dbd.CHR olefins in which R is an alkyl,
cycloalkyl or aryl radical with 1-10 carbon atoms in which the
catalyst used is obtained from a component according to claim
16.
25. Polyolefins obtainable from the process of claim 22.
26. Manufactured goods obtained from the polymers according to
claim 25.
Description
[0001] The present invention relates to components of catalysts for
the polymerization of olefins, the catalysts obtained therefrom and
the use of said catalysts in the polymerization of olefins
CH.sub.2.dbd.CHR, in which R is hydrogen or an alkyl, cycloalkyl or
aryl radical with 1-10 carbon atoms. Another aspect of the present
invention relates to the polymers obtained using said
catalysts.
[0002] Catalysts are known from the literature that are obtained
from compounds ML.sub.x in which M is a transition metal,
especially Ti, Zr and Hf, L is a ligand coordinating on the metal,
x is the valence of the metal and at least one of the ligands L has
cyclo-alkadienyl structure. Catalysts of this type using compounds
Cp.sub.2TiCl.sub.2 or Cp.sub.2ZrCl.sub.2 (Cp=cyclopentadienyl) are
described in U.S. Pat. Nos. 2,827,446 and 2,924,593. The compounds
are used together with alkyl-Al compounds in the polymerization of
ethylene. The catalytic activity is very low. Catalysts with very
high activity are obtained from compounds Cp.sub.2ZrCl.sub.2 or
Cp.sub.2TiCl.sub.2 and from their derivatives substituted in the
cyclopentadienyl ring, in which the Cp ring can also be condensed
with other rings, and from polyalumoxane compounds containing the
repeating unit --(R)AlO--, in which R is a lower alkyl, preferably
methyl (U.S. Pat. No. 4,542,199 and EP-A-129368).
[0003] Catalysts of the type mentioned above, in which the
metallocene compound contains two indenyl or tetrahydroindenyl
rings bridge-bonded through lower alkylenes or through other
divalent radicals, are suitable for the preparation of
stereoregular polymers of propylene and other .alpha.-olefins
(EP-A-185918).
[0004] Stereospecific catalysts are also obtained from
dicyclopentadienyl compounds in which the two rings are substituted
differently with groups having steric hindrance such as to prevent
rotation of the rings about the axis of coordination with the
metal.
[0005] Substitution of indenyl or tetrahydroindenyl in suitable
positions gives catalysts that have very high stereospecificity
(EP-A-485823, EP-A-485820, EP-A-519237, U.S. Pat. No. 5,132,262 and
U.S. Pat. No. 5,162,278).
[0006] The metallocene catalysts described above produce polymers
with a very narrow molecular weight distribution (Mw/Mn of about
2).
[0007] Some of these catalysts also have the property of forming
copolymers of ethylene with .alpha.-olefins of the LLDPE type or
ethylene/propylene elastomeric copolymers with very uniform
distribution of the comonomer units. The LLDPE polyethylene
obtained is further characterized by low solubility in solvents
such as xylene or n-decane.
[0008] The polypropylene obtained with the highly stereospecific
catalysts mentioned above has greater crystallinity and a higher
deformation temperature compared with the polymer that can be
obtained with the conventional Ziegler-Natta catalysts.
[0009] However, these metallocene catalysts have a considerable
drawback with respect to the possibility of being employed in
industrial processes for production of polyolefins that are not
carried out in solution, owing to the fact that they are soluble in
the reaction medium in which they are prepared and in the liquid
medium of polymerization.
[0010] In order to be usable in gas-phase polymerization processes,
the catalysts must be supported on suitable supports which endow
the polymer with appropriate morphological properties.
[0011] Supports of various kinds have been used, including, among
others, porous metal oxides such as silica or porous polymeric
supports such as polyethylene, polypropylene and polystyrene. The
halides of magnesium are also used as supports. In some cases
magnesium halides are also used as counterion of an ion pair in
which the metallocene compound supplies the cation and a compound,
such as a Mg halide, supplies the anion.
[0012] When Mg halide is used for supplying the anion, the
catalytic system is formed by the halide present in solid form and
the metallocene compound dissolved in a solvent. A system of this
type cannot be used in gas-phase polymerization processes. Mg
halide is preferably used in finely divided form that can be
obtained by grinding.
[0013] As support, Mg halide is used in pulverized form, obtainable
by grinding. Catalysts obtained in this way are not of high
performance. Sufficiently high yields can only be obtained when the
Mg halide is used in a form in which it is partially complexed with
an electron-donor compound, obtained by a special method of
preparation.
[0014] Japanese Application No. 168408/88 (published on Dec. 7,
1988) describes the use of magnesium chloride as support for
metallocene compounds, such as Cp.sub.2TiCl.sub.2,
Cp.sub.2ZrCl.sub.2, Cp.sub.2Ti(CH.sub.3).sub.2 for forming, with
trialkyl aluminium and/or polymethylalumoxane (MAO), catalysts for
the polymerization of ethylene. The component containing the
magnesium chloride is prepared by grinding MgCl.sub.2 with the
metallocene compound, also working in the presence of
electron-donor compounds. Alternatively, the component is prepared
by treating the metallocene with a liquid MgCl.sub.2-alcohol adduct
and subsequent reaction with AlEt.sub.2Cl. The catalyst activity,
referred to MgCl.sub.2 is very low.
[0015] Catalysts comprising a metallocene compound of the type
Cp.sub.2ZrCl.sub.2 supported on MgCl.sub.2 in spherical form and
partially complexed with an electron-donor compound are described
in U.S. Pat. No. 5,106,804. The performance of these catalysts is
better than that described in Japanese Application No. 168408/88
but is still not satisfactory, since it is not possible to obtain
polymers containing sufficiently low residues of the catalyst. The
electron donor used must be free from atoms of active hydrogen and
in addition must be uniformly distributed in the bulk of the Mg
halide. Suitable supports cannot be obtained by mere mixing of the
components. Homogeneous dispersion of the electron donor is
obtained by forming the Mg halide (by halogenation of Mg-dialkyls)
in the presence of a solvent containing the electron donor in
dissolved form. The surface area of the Mg halide is not greater
than 100 m.sup.2/g, and is preferably between 30 and 60 m.sup.2/g.
No information is given with respect to the porosity of the
support. The electron-donor compound is used in a quantity of from
0.5 to 15 mol % based on the Mg halide; its presence is necessary.
The catalysts obtained have performance that is much lower than
that of the corresponding unsupported catalysts in which the
metallocene compound is used in solution.
[0016] Application EP-A-318048 describes catalysts in which a solid
component comprising a compound of Ti supported on a magnesium
chloride that has particular characteristics of surface area and of
porosity and possibly an electron-donor compound, is used with
benzyl compounds of Ti or Zr or with metallocene compounds of the
type Cp.sub.2Ti(CH.sub.3).sub.- 2 and
bis-(indenyl)-Zr(CH.sub.3).sub.2 for forming catalysts for
polymerization of ethylene and of propylene. The weight ratio of
metallocene to magnesium chloride is very high (greater than 1), so
it is necessary to remove the metallocene from the obtained
polymer. The catalysts are used in processes that are carried out
in the presence of a liquid polymerization medium.
[0017] Application EP-A-439964 describes bimetallic catalysts
suitable for the preparation of ethylene polymers with broad
molecular weight distribution (Mw/Mn between 4 and 14) obtained by
supporting a metallocene on a solid component containing a Ti
compound supported on MgCl.sub.2. MAO or its mixtures with alkyl-Al
are used as cocatalyst. Trialkyl-Al compounds are also used as
cocatalysts but the catalytic activity is low. The yields of these
mixed catalysts with active centres derived either from the Ti
compound supported on MgCl.sub.2 or from the metallocene compound
are very high when the catalysts are used in a hydrocarbon medium;
on the other hand they are low when polymerization is effected in
the gas phase. This is probably due to the fact that, when using a
hydrocarbon medium, as the metallocene compound is not fixed to the
support in a stable form, it dissolves in the hydrocarbon
polymerization solvent. In practice, the obtained catalyst
corresponds to a homogeneous catalyst in which the metallocene
compound is used in solution. Working in the gas phase, the
metallocene compound is present as a solid and the catalyst
obtained therefrom has an activity lower than that of the
corresponding catalyst used in solution.
[0018] Application EP-A-522281 describes catalysts obtained from
Cp.sub.2ZrCl.sub.2 supported on MgCl.sub.2 and from mixtures of
trialkyl-Al and compounds supplying stable anions of the type
dimethylaniline-tetrakis-(pentafluorophenyl)-borate. The catalysts
are prepared by grinding the components and are used to polymerize
ethylene in the presence of a solvent (toluene) with good yields
(based on MgCl.sub.2). In this case too, the metallocene compound
is present largely in solution and not fixed to MgCl.sub.2 and the
relatively high activity based on MgCl.sub.2 is due essentially to
the catalyst dissolved in the polymerization medium.
[0019] Application EP-A-509944 describes catalysts using
aniline-tetrakis-(pentafluorophenyl)-borate or Lewis acids such as
MgCl.sub.2 together with metallocene halides pre-reacted with
alkyl-Al compounds. The magnesium chloride is ground before being
contacted with the pre-reacted metallocene compound. The yields of
polymer based on the Mg halide are not high (less than about 100 g
polymer/g MgCl.sub.2). The Mg halide has surface are between 1 and
300 m.sup.2/g, preferably between 30 and 300 m.sup.2/g. Mg chloride
with area between 30 and 300 m.sup.2/g is obtained essentially by
grinding the commercial chloride. In this case it is difficult for
the area to exceed 100-150 m.sup.2/g and the porosities are
relatively low (less than 0.1 cm.sup.3/g). Also in the case of the
catalysts described in Application EP-A-509944 the yields should
largely be attributed to the metallocene compound dissolved in the
polymerization solvent.
[0020] Application EP-A-588404 describes catalysts obtained from
metallocene compounds supported on Mg halides prepared by
halogenation of dialkyl-Mg or alkyl-Mg halides with SiCl.sub.4 or
SnCl.sub.4. The yields of polymer (polyethylene) per g of solid
component and per g of Zr are relatively high, especially when the
catalyst is obtained from MgCl.sub.2 prepared using SnCl.sub.4.
Again in this case it is to be assumed that the high catalytic
activity is due more to the catalyst derived from the metallocene
compound that dissolves in the polymerization medium than from that
derived from the metallocene compound actually supported on the Mg
halide.
[0021] European Application EP-A-576213 describes catalysts
obtained from a solution of MgCl.sub.2 in an alkanol, from a
trialkyl-Al compound and from a metallocene compound. The yields of
polymer are very low. The catalyst is practically inactive when the
MgCl.sub.2 solution is replaced by solid MgCl.sub.2 activated by
prolonged grinding.
[0022] Solid components have now unexpectedly been found that
comprise a metallocene compound and a magnesium halide, capable of
giving catalysts that have very high activity in the polymerization
of olefins, characterized by surface area (BET method) greater than
about 50 m.sup.2/g, porosity (BET method) greater than about 0.15
cm.sup.3/g and porosity (Hg method) greater than 0.3 cm.sup.3/g,
with the proviso that when the surface area is less than about 150
m.sup.2/g, the porosity (Hg) is less than about 1.5 cm.sup.3/g.
[0023] The porosity and surface area according to the BET method
are determined using the "SORPTOMATIC 1800" apparatus from Carlo
Erba.
[0024] The porosity according to the Hg method is determined using
a "Porosimeter 2000 series" porosimeter from Carlo Erba, following
the procedure described below.
[0025] The porosity (BET) is preferably above 0.2 cm.sup.3/g and in
particular between 0.3 and 1 cm.sup.3/g. The surface area (BET) is
preferably greater than 100 m.sup.2/g and more preferably greater
than 150 m.sup.2/g. A very convenient range is between 150 and 800
m.sup.2/g. Components with surface area less than 150 m.sup.2/g
give catalysts with performance that is of interest, provided that
the porosity (Hg method) is less than about 1.5 cm.sup.3/g,
preferably between 0.4 and 1.2 cm.sup.3/g, and in particular
between 0.5 and 1.1 cm.sup.3/g.
[0026] The components are preferably used in the form of spherical
particles smaller than 150 .mu.m.
[0027] In the components with surface area (BET) less than 150
m.sup.2/g more than 50% of the porosity (BET) is due to pores with
radius greater than 300 .ANG. and preferably between 600 and 1000
.ANG..
[0028] The components with surface area (BET) greater than 150
m.sup.2/g and in particular greater than 200 m.sup.2/g exhibit,
along with porosity (BET) due to pores with radius between 300 and
1000 .ANG., also porosity (BET) due to pores with radius between
about 10 and 100 .ANG.. In general, more than 40% of the porosity
(BET) is due to pores with radius greater than 300 .ANG..
[0029] The mean dimensions of the crystallites of Mg halide present
in the solid component are generally below 300 .ANG. and more
preferably below 100 .ANG.. The definition of the components of the
invention also includes those components which, in normal
conditions, do not display the values of area and porosity stated
above but attain them after treatment with a solution of
trialkyl-Al at 10% in n-hexane at 50.degree. C. for 1 hour.
[0030] The components of the invention are prepared by supporting a
metallocene compound on an Mg halide or on a support containing Mg
halide that has characteristics of surface area and of porosity
that are within the ranges stated for the catalytic component.
[0031] In general the surface area (BET) and the porosity (BET) and
porosity (Hg) of the starting magnesium halide are greater than
those of the component obtained from it.
[0032] Preferred Mg halides have surface area (BET) greater than
200 m.sup.2/g and more preferably between 300 and 800 m.sup.2/g and
porosity (BET) greater than 0.3 cm.sup.3/g.
[0033] The Mg halide can comprise, in smaller proportions, other
components acting as co-support or used for improving the
properties of the catalytic component. Examples of these components
are AlCl.sub.3, SnCl.sub.4, Al(OEt).sub.3, MnCl.sub.2, ZnCl.sub.2,
VCl.sub.3, Si(OEt).sub.4.
[0034] The Mg halide can be complexed with electron-donor compounds
not containing active hydrogen in a quantity up to about 30 mol %,
preferably 5-15 mol % based on the Mg halide. Examples of electron
donors are ethers, esters, ketones.
[0035] The Mg halide can in its turn be supported on an inert
support that has area and porosity such that the supported product
has the values stated above. Suitable inert supports can be metal
oxides such as silica, alumina, silica-alumina, possessing porosity
(BET) greater than 0.5 cm.sup.3/g and surface area (BET) greater
than 200 m.sup.2/g and for example between 300 and 600
m.sup.2/g,
[0036] Other inert supports can be porous polymers such as
polyethylene, polypropylene and polystyrene.
[0037] Partially crosslinked polystyrene that has high values of
surface area and porosity is particularly suitable.
[0038] Polystyrenes of this type are described in U.S. Pat. No.
5,139,985, whose description of the method of preparation and
supporting of the magnesium halide is included here for reference.
These polystyrenes generally have surface area (BET) between 100
and 600 m.sup.2/g and porosity (BET) greater than 0.5
cm.sup.3/g.
[0039] The amount of Mg halide that can be supported is generally
between 1 and 20% by weight based on the mixture. The preferred Mg
halide is Mg chloride. The Mg halide can be supported according to
known methods, starting from its solutions in solvents such as
tetrahydrofuran or by impregnation of the inert support with
solutions of the halide in an alcohol; the alcohol is then removed
by reaction with a compound such as a trialkyl-Al or dialkyl-Al
halide or silicon halides. The alcohols used are generally alkanols
with 1-8 carbon atoms.
[0040] A method that is very suitable for preparation of Mg halides
that have the characteristics of porosity and area stated above,
consists of reacting spherulized adducts of MgCl.sub.2 with
alcohols, the said adducts containing from 0.1 to 3 mol of alcohol
with alkyl-Al compounds, in particular triethyl-Al, triisobutyl-Al,
AlEt.sub.2Cl.
[0041] A preparation of this type is described in U.S. Pat. No.
4,399,054 whose description is herein included for reference.
[0042] For the purpose of obtaining supports with morphological
characteristics that are particularly suitable for gas-phase
polymerization processes in a fluidized bed, the adduct of
MgCl.sub.2 with about 3 mol of alcohol should be submitted, prior
to reaction with the alkyl-Al, to a controlled partial
dealcoholizing treatment such as that described in European Patent
Application EP-A-553806, to which reference is made for the
description. The Mg halides thus obtained have a spheroidal shape,
mean dimensions less than 150 microns, surface area (BET) greater
than 60-70 m.sup.2/g and generally between 60 and 500
m.sup.2/g.
[0043] Other methods of preparation of the Mg halides suitable for
preparation of the components of the invention are those described
in European Patent Application EP-A-553805, whose description is
herein included for reference.
[0044] Supporting of the metallocene compound is carried out
according to known methods by bringing the Mg halide into contact,
for example, with a solution of the metallocene compound, operating
at temperatures between room temperature and 120.degree. C. The
metallocene compound that is not fixed on the support is removed by
filtration or similar methods or by evaporating the solvent.
[0045] The amount of metallocene compound supported is generally
between 0.1 and 5% by weight expressed as metal.
[0046] The atomic ratio of Mg to transition metal is generally
between 10 and 200; it can, however, be less and reach values of 1
or even less when the Mg halide is supported on an inert
support.
[0047] The metallocene compounds are sparingly soluble in
hydrocarbons (the hydrocarbon solvents most used are benzene,
toluene, hexane, heptane and the like). Their solubility increases
considerably if the solvent contains a dissolved alkyl-Al compound
such as triethyl-Al, triisobutyl-Al or a polyalkylalumoxane in
particular MAO (polymethyl-alumoxane) in molar ratios with the
metallocene compound greater than 2 and preferably between 5 and
100.
[0048] Impregnation of the support starting from the solution
mentioned above makes it possible to obtain particularly active
catalysts (the activity is greater than that of the catalysts that
can be obtained from solutions of the metallocene compound that do
not contain the alkyl-Al compound or MAO).
[0049] The metallocene compounds that can be used are selected from
the compounds of a transition metal M selected from Ti, V, Zr and
Hf containing at least one metal-.pi. bond, and comprising
preferably at least one ligand L coordinated on the metal M
possessing a mono- or polycyclic structure containing conjugated
.pi. electrons.
[0050] The said compound of Ti, V, Zr or Hf is preferably selected
from components possessing the structure:.
Cp.sup.IMR.sup.1.sub.aR.sup.2.sub.bR.sup.3.sub.c (I)
Cp.sup.I1Cp.sup.IIMR.sup.1.sub.aR.sup.2.sub.b (II)
(Cp.sup.I--A.sub.c--Cp.sup.II) M.sup.1R.sup.1.sub.aR.sup.2.sub.b
(III)
[0051] in which M is Ti, V, Zr or Hf; Cp.sup.I and Cp.sup.II,
identical or different, are cyclopentadienyl groups, including
substituted ones; two or more substituents on the said
cyclopentadienyl groups can form one or more rings possessing from
4 to 6 carbon atoms; R.sup.1, R.sup.2 and R.sup.3, identical or
different, are atoms of hydrogen, halogen, an alkyl or alkoxyl
group with 1-20 carbon atoms, aryl, alkaryl or aralkyl with 6-20
carbon atoms, an acyloxy group with 1-20 carbon atoms, an allyl
group, a substituent containing a silicon atom; A is an alkenyl
bridge or one with structure selected from: 1
[0052] in which M.sub.1 is Si, Ge, or Sn; R.sub.1 and R.sub.2,
identical or different, are alkyl groups with 1-4 carbon atoms or
aryl groups with 6-10 carbon atoms; a, b, c are, independently,
integers from 0 to 4; e is an integer from 1 to 6 and two or more
of the radicals R.sup.1, R.sup.2 and R.sup.3 can form a ring. In
the case when the Cp group is substituted, the substituent is
preferably an alkyl group with 1-20 carbon atoms.
[0053] Representative compounds that have formula (I) include:
(Me.sub.5Cp)MMe.sub.3, (Me.sub.5Cp)M(OMe).sub.3,
(Me.sub.5Cp)MCl.sub.3, (Cp)MCl.sub.3, (Cp)MMe.sub.3,
(MeCp)MMe.sub.3, (Me.sub.3Cp)MMe.sub.3, (Me.sub.4Cp)MCl.sub.3,
(Ind)MBenz.sub.3, (H.sub.4Ind)MBenz.sub.3, (Cp)MBu.sub.3.
[0054] Representative compounds that have formula (II) include:
(Cp).sub.2MMe.sub.2, (Cp).sub.2MPh.sub.2, (Cp).sub.2MEt.sub.2,
(Cp).sub.2MCl.sub.2, (Cp).sub.2M(OMe).sub.2, (Cp).sub.2M(OMe)Cl,
(MeCp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2MCl.sub.2,
(Me.sub.5Cp).sub.2MMe.sub.2, (Me.sub.5Cp).sub.2MMeCl,
(Cp)(Me.sub.5Cp)MCl.sub.2, (1-MeFlu).sub.2MCl.sub.2,
(BuCp).sub.2MCl.sub.2, (Me.sub.3Cp).sub.2MCl.sub.2,
(Me.sub.4Cp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2M(OMe).sub.2,
(Me.sub.5Cp).sub.2M(OH)Cl, (Me.sub.5Cp).sub.2M(OH).sub.2,
(Me.sub.5Cp).sub.2M(C.sub.6H.sub.5).sub.2,
(Me.sub.5Cp).sub.2M(CH.sub.3)C- l, (EtMe.sub.4Cp).sub.2MCl.sub.2,
[(C.sub.6H.sub.5)Me.sub.4Cp].sub.2MCl.su- b.2,
(Et.sub.5Cp).sub.2MCl.sub.2, (Me.sub.5Cp).sub.2M(C.sub.6H.sub.5)Cl,
(Ind).sub.2MCl.sub.2, (Ind).sub.2MMe.sub.2,
(H.sub.4Ind).sub.2MCl.sub.2, (H.sub.4Ind).sub.2MMe.sub.2,
{[Si(CH.sub.3).sub.3]Cp}.sub.2MCl.sub.2,
{[Si(CH.sub.3).sub.3].sub.2Cp}.sub.2MCl.sub.2,
(Me.sub.4Cp)(Me.sub.5Cp)MC- l.sub.2.
[0055] Representative compounds of formula (III) include:
C.sub.2H.sub.4(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(Ind).sub.2MMe.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind).sub- .2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MMe.sub.2, Me.sub.2SiCp.sub.2MCl.sub.2,
Me.sub.2SiCp.sub.2MMe.sub.2, Me.sub.2Si(Me.sub.4Cp).sub.2MMeOMe,
Me.sub.2Si(Flu).sub.2MCl.sub.2,
Me.sub.2Si(2-Et-5-iPrCp).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Ind).sub.2MCl.sub.2,
Me.sub.2Si(H.sub.4Flu).sub.2MCl.su- b.2,
Me.sub.2SiCH.sub.2(Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-H.sub.4Ind)MC- l.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2, Me.sub.2Si(2-Et-5-iPr-Cp).sub-
.2MCl.sub.2, Me.sub.2Si(2-Me-5-EtCp).sub.2MCl.sub.2,
Me.sub.2Si(2-Me-5-Me-Cp).sub.2MCl.sub.2,
Me.sub.2Si(2Me-4,5-benzoindenyl)- .sub.2MCl.sub.2,
Me.sub.2Si(4,5-benzoindenyl).sub.2MCl.sub.2,
Me.sub.2Si(2-EtInd).sub.2MCl.sub.2,
Me.sub.2Si(2-iPr-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2-t-butyl-Ind)MCl.sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MCl- .sub.2,
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2MMe.sub.2,
Me.sub.2Si(2-MeInd).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-4,5-benzoindenyl)- .sub.2MCl.sub.2,
Me.sub.2C(Flu)CpMCl.sub.2, Ph.sub.2Si(Ind).sub.2MCl.sub.2- ,
Ph(Me)Si(Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind)M(NMe.sub.2)OMe,
isopropylidene-(3-t-butyl-Cp)(Flu)MCl.sub.2,
Me.sub.2C(Me.sub.4Cp)(MeCp)M- Cl.sub.2, MeSi(Ind).sub.2MCl.sub.2,
Me.sub.2Si(Ind).sub.2MMe.sub.2,
Me.sub.2Si(Me.sub.4Cp).sub.2MCl(OEt),
C.sub.2H.sub.4(Ind).sub.2M(NMe.sub.- 2).sub.2,
C.sub.2H.sub.4(Me.sub.4Cp).sub.2MCl.sub.2,
C.sub.2Me.sub.4(Ind).sub.2MCl.sub.2,
Me.sub.2Si(3-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2-Me-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3-Me-Ind).sub.2MC- l.sub.2,
C.sub.2H.sub.4(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.- sub.3Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(3,4,7-Me.sub.3Ind).sub.2MCl.sub.2- ,
C.sub.2H.sub.4(2-Me-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(4,7-Me.su- b.2-H.sub.4Ind).sub.2MCl.sub.2,
C.sub.2H.sub.4(2,4,7-Me.sub.3-H.sub.4Ind).- sub.2MCl.sub.2,
Me.sub.2Si(4,7-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(5,6-Me.sub.2-Ind).sub.2MCl.sub.2,
Me.sub.2Si(2,4,7-Me.sub.3-H.- sub.4Ind).sub.2MCl.sub.2.
[0056] In the simplified formulae given above, the symbols have the
following meanings: Me=methyl, Et=ethyl, iPr=isopropyl, Bu=butyl,
Ph=phenyl, Cp=cyclopentadienyl, Ind=indenyl,
H.sub.4Ind=4,5,6,7-tetrahydr- oindenyl, Flu=fluorenyl, Benz=benzyl,
M=Ti, Zr or Hf, preferably Zr.
[0057] Compounds of the type Me.sub.2Si(2-Me-Ind).sub.2ZrCl.sub.2
and Me.sub.2Si(2-Me-H.sub.4Ind)ZrCl.sub.2 and their methods of
preparation are described respectively in European Applications
EP-A-485822 and 485820 whose description is included here for
reference.
[0058] Compounds of the type
Me.sub.2Si(3-t-butyl-5-MeCp).sub.2ZrCl.sub.2 and of the type
Me.sub.2Si(2-Me-4,5-benzoindenyl)ZrCl.sub.2 and their method of
preparation are described respectively in U.S. Pat. No. 5,132,262
and in Patent Application EP-A-549900 whose description is included
here for reference.
[0059] The components of the invention form, with alkyl-Al
compounds or with polyalkyl-alumoxane compounds or their mixtures,
catalysts that possess very high activity relative to the Mg
halide.
[0060] The alkyl-Al compound is generally selected from compounds
of formula AlR.sub.3, in which R is an alkyl that has 1-12 carbon
atoms, and the alumoxane compounds containing the repeating unit
--(R.sup.4)AlO--, in which R.sup.4 is an alkyl radical containing
from 1 to 6 carbon atoms, and the said alumoxane compounds contain
from 2 to 50 repeating units that have the formula described above.
Typical examples of compounds that have the formula AlR.sub.3 are
trimethyl-Al, triethyl-Al, triisobutyl-Al, tri-n-butyl-Al,
trihexyl-Al, trioctyl-Al. Among the alumoxane compounds, use of MAO
is preferable. Mixtures of alkyl-Al compounds, preferably
triisobutyl-Al, and alumoxane compounds, preferably MAO, are also
used advantageously.
[0061] When the transition metal compound containing at least one
M-.pi. bond is of the type described in formulae (II) and (III),
the compounds obtained from the reaction between AlR.sub.3 and
H.sub.2O in molar ratios between 0.01 and 0.5 can be used
advantageously.
[0062] In general the alkyl-Al compound is used in molar ratios
relative to the transition metal between 10 and 5000, preferably
between 100 and 4000, and more preferably between 500 and 2000.
[0063] The catalysts of the invention can be used for
(co)polymerizing CH.sub.2.dbd.CHR olefins, in which R is hydrogen
or an alkyl radical with 1-10 carbon atoms or an aryl.
[0064] They are used in particular for polymerizing ethylene and
its mixtures with .alpha.-olefins of the type stated above in which
R is an alkyl radical.
[0065] The catalysts, particularly those obtained from compounds of
the type C.sub.2H.sub.4(Ind).sub.2ZrCl.sub.2,
C.sub.2H.sub.4(H.sub.4Ind)ZrCl.- sub.2 and
Me.sub.2Si(Me.sub.4Cp).sub.2ZrCl.sub.2, are suitable for producing
LLDPE (copolymers of ethylene containing smaller proportions,
generally below 20 mol %, of .alpha.-olefin C.sub.3-C.sub.12)
characterized by relatively low density values in relation to the
content of .alpha.-olefin, with reduced solubility in xylene at
room temperature (below approx. 10% by weight) and with molecular
weight distribution Mw/Mn between about 2.5 and 5.
[0066] The polypropylenes that can be obtained with the catalysts
using a chiral metallocene compound are characterized by increased
stereoregularity, high molecular weights that are easily
controllable, and high degree of crystallinity.
[0067] The chiral metallocene compounds that can be used are for
example of the type described in European Application EP-A-485823,
EP-A-485820, EP-A-519237, and U.S. Pat. Nos. 5,132,262, and
5,162,278.
[0068] The following examples are given for the purpose of
illustrating but not limiting the invention. The properties stated
are determined in accordance with the following methods:
[0069] Porosity and surface area (BET): are determined according to
BET methods (apparatus used: SORPTOMATIC 1800 from Carlo Erba). The
porosity is calculated from the integral pore distribution curve in
function of the pores themselves.
[0070] Porosity and surface area with mercury: are determined by
immersing a known quantity of the sample in a known quantity of
mercury inside a dilatometer and then gradually increasing the
pressure of the mercury hydraulically. The pressure of introduction
of the mercury into the pores is a function of their diameter.
Measurement is effected using a "Porosimeter 2000 series"
porosimeter from Carlo Erba. The porosity, pore distribution and
surface area are calculated from data on the decrease of volume of
the mercury and from the values of the applied pressure.
[0071] The porosity and surface areas stated in the descriptions
and in the examples are referred to pore dimensions up to 10000
.ANG..
[0072] Size of the catalyst particles: is determined by a method
based on the principle of optical diffraction of monochromatic
laser light with the "Malvern Instr. 2600" apparatus. The average
size is stated as P50.
[0073] Melt Index E (MIE): determined according to ASTM-D 1238,
method E.
[0074] Melt Index F (MIF): determined according to ASTM-D 1238,
method F.
[0075] Ratio of degrees (F/E): ratio between Melt Index F and Melt
Index E.
[0076] Flowability: is the time taken for 100 g of polymer to flow
through a funnel whose discharge hole has a diameter of 1.25 cm and
whose walls are inclined at 20.degree. to the vertical.
[0077] Apparent density: DIN 53194.
[0078] Morphology and granulometric distribution of the particles
of polymer: ASTM-D 1921-63.
[0079] Fraction soluble in xylene: measured by dissolving the
polymer in boiling xylene and determining the insoluble residue
after cooling to 25.degree. C.
[0080] Content of comonomer: percentage by weight of comonomer
determined from IR spectrum.
[0081] Density: ASTM-D 792.
[0082] Average size of MgCl.sub.2 crystallites [D(110)]: is
determined from measurement of the width at half-height of the
(110) diffraction line that appears in the X-ray spectrum of the
magnesium halide, applying Scherrer's equation:
D(110)=(K.multidot.1.542.multidot.57.3)/(B-b)cos .theta.,
[0083] in which:
[0084] K=constant (1.83 in the case of magnesium chloride);
[0085] B=half-width (in degrees) of the (110) diffraction line;
[0086] b=instrumental broadening;
[0087] .theta.=Bragg angle.
[0088] In the case of magnesium chloride, the (110) diffraction
line appears at an angle 2.theta. of 50.2.degree..
EXAMPLES
Example 1
Preparation of the Support
[0089] A spherical adduct MgCl.sub.2.3EtOH was prepared according
to the procedure described in Example 2 of Patent U.S. Pat. No.
4,399,054, operating at 3000 rpm instead of at 10000 rpm. The
adduct was partially dealcoholized by heating in a stream of
nitrogen at temperatures increasing from 30.degree. C. to
180.degree. C., until an adduct containing 10% by weight of EtOH
was obtained.
Preparation of the Metallocene/Triisobutylaluminium Solution
[0090] A reactor with capacity of 1000 cm.sup.3, equipped with an
anchor stirrer and treated with N.sub.2, was fed with 382.5
cm.sup.3 of triisobutylaluminium (TIBAL) in hexane solution (100
g/liter) and 14.25 g of ethylene-bis-indenyl zirconium dichloride
(EBI). The system was stirred in N.sub.2 atmosphere at 20.degree.
C. for 1 hour. A clear solution was obtained at the end of this
period.
Preparation of the Catalyst
[0091] A reactor with capacity of 1000 cm.sup.3, equipped with an
anchor stirrer, and treated with N.sub.2 at 90.degree. C. for 3
hours, was loaded, at 20.degree. C. in a nitrogen atmosphere, with
600 cm.sup.3 of heptane and 60 g of the support prepared
previously. While stirring at 20.degree. C., 238 cm.sup.3 of hexane
solution of TIBAL (100 g/l) were introduced in 30 minutes. The
mixture was heated to 80.degree. C. in 1 hour and kept at this
temperature for 2 hours. The mixture was then cooled to 20.degree.
C. and 62.5 cm.sup.3 of the TIBAL/EBI solution previously prepared
were added. The system was heated to 60.degree. C. in 30 minutes
and kept at this temperature for 2 hours. At the end of this period
3 washings with hexane were effected at 60.degree. C., removing the
solvent by evaporation under vacuum at maximum temperature of about
60.degree. C. Approximately 62 g of spherical catalyst, with the
following characteristics, was obtained: Mg=21.33%; Cl=66.59%;
Al=0.96%; Zr=0.41%; EtO=0.3%;
[0092] Surface area (Hg) 70.9 m.sup.2/g
[0093] Porosity (Hg) 1.041 cm.sup.3/g
[0094] Surface area (BET) 61.9 m.sup.2/g
[0095] Porosity (BET) 0.687 cm.sup.3/g
Polymerization (LLDPE)
[0096] 0.05 g of the catalyst described above and 0.42 g of methyl
alumoxane (MAO) in 100 cm.sup.3 of toluene were precontacted for 5
minutes at 20.degree. C. in a glass flask, which had been treated
with N.sub.2 at 90.degree. C. for 3 hours. The whole was placed in
a 4-liter steel autoclave, equipped with an anchor stirrer, and
treated with N.sub.2 at 90.degree. C. for 3 hours, containing 800 g
of propane at 30.degree. C. The autoclave was heated to 75.degree.
C. and 0.1 bar of H.sub.2 was introduced and then, simultaneously,
7 bar of ethylene and 100 g of 1-butene. Polymerization was carried
out for 1 hour, keeping the temperature and the ethylene pressure
constant. 115 g of ethylene-butene copolymer was obtained (g
copolymer per g catalyst=2300; kg copolymer per g Zr=545) with the
following characteristics: MIE=0.84; F/E=49.16; .eta.=1.35;
density=0.914; butene=10.1%; insoluble in xylene=97.42%.
Polymerization (HDPE)
[0097] 0.42 g of MAO and 0.05 g of the catalyst described above in
100 cm.sup.3 of toluene were precontacted for 5 minutes at
30.degree. C. in a glass flask that had been treated with N.sub.2
at 90.degree. C. for 3 hours. The whole was then placed in a
4-liter steel autoclave, equipped with an anchor stirrer and
treated with N.sub.2 at 90.degree. C. for 3 hours, containing 1.6
liters of hexane at 20.degree. C. The autoclave was heated to
75.degree. C. and 7 bar of ethylene and 0.25 bar of H.sub.2 were
introduced. Polymerization was effected for 1 hour, keeping the
ethylene temperature and pressure constant. Polymerization was
stopped by instantaneous degassing of the autoclave and, after
cooling to 20.degree. C., the polymer slurry was discharged and was
dried at 80.degree. C. in nitrogen atmosphere. 100 g of
polyethylene were obtained (2000 g polyethylene/g catalyst; 492 kg
polyethylene/g Zr), with the following characteristics: MIE=12.9;
F/E=22.5; .eta.=0.7.
Example 2
Preparation of the Metallocene/Alumoxane Solution
[0098] A 1000 cm.sup.3 reactor, equipped with an anchor stirrer and
treated with N.sub.2, was loaded with 600 cm.sup.3 of toluene,
18.87 g of polymethyl-alumoxane (MAO) and 8.46 g of EBI. The system
was stirred in an atmosphere of N.sub.2 at 20.degree. C. for 1
hour. A clear solution was obtained at the end of this period.
Preparation of the Catalyst
[0099] A 1000 cm.sup.3 reactor, equipped with an-anchor stirrer and
treated with N.sub.2 at 90.degree. C. for 3 hours, was fed, in an
atmosphere of N.sub.2 at 20.degree. C., with 600 cm.sup.3 of
heptane and 60 g of support prepared according to the methodology
in Example 1. While stirring at 20.degree. C., 86.4 cm.sup.3 of
solution of trimethylaluminium (TMA) in hexane (100 g/liter) were
introduced in 30 minutes. In 1 hour the system was heated to
80.degree. C. and was maintained at this temperature for 2 hours.
The mixture was then cooled to 20.degree. C. and 62.5 cm.sup.3 of
the MAO/EBI solution previously prepared were introduced. The
system was heated to 60.degree. C. in 30 minutes and was kept at
this temperature for 2 hours. At the end of this period, 3 washings
with hexane were effected at 60.degree. C., removing the solvent by
evaporation under vacuum at maximum temperature of about 60.degree.
C. 65 g of spherical catalyst with the following characteristics
was obtained: Mg=19.3%; Cl=61.5%; Al=3.87%; Zr=0.33%; OEt=4.3%.
Polymerization (HDPE)
[0100] 0.05 g of the catalyst described above was precontacted with
MAO (0.42 g) in the conditions of Example 2. Then ethylene was
polymerized in the conditions in Example 2, obtaining 100 g of
polymer (2000 g polyethylene/g cat; 575 kg polymer/g Zr) with the
following characteristics: MIE=9.5; F/E=12.68; .eta.=0.66.
Example 3
Preparation of the Metallocene/Alumoxane Solution
[0101] Preparation was effected in the same conditions as Example 2
but using 47.18 g of MAO instead of 18.87 g.
Preparation of the Catalyst
[0102] The catalyst was prepared following the procedure described
in Example 2, using 166.6 cm.sup.3 of the metallocene-alumoxane
solution described above. Once the solvent had been removed by
evaporation, approx. 65 g of spherical catalyst with the following
characteristics were obtained: Mg=18.41; Cl=57.5; Al=5.56;
Zr=0.42.
Polymerization (HDPE)
[0103] 0.05 g of the catalyst described above was precontacted and
polymerized in the same conditions as in Example 1, using 0.1 bar
of H.sub.2 instead of 0.25 bar. 80 g of polyethylene were obtained
(1600 g polyethylene/g cat; 381 kg polyethylene/g Zr), with the
following characteristics: MIE=5.9; F/E=17.9; .eta.=0.77.
Example 4
Preparation of the Support
[0104] A spherical adduct MgCl.sub.2.3EtOH was prepared following
the procedure described in Example 2 of Patent U.S. Pat. No.
4,399,054, operating at 3000 rpm instead of at 10000 rpm. The
adduct was partially dealcoholized by heating in a stream of
nitrogen at temperatures increasing from 30.degree. C. to
180.degree. C., until an adduct containing 35% by weight of EtOH
was obtained.
Preparation of the Metallocene/Triisobutylaluminium Solution
[0105] A reactor with capacity of 1000 cm.sup.3, equipped with an
anchor stirrer and treated with N.sub.2, was loaded with 382.5
cm.sup.3 of triisobutylaluminium (TIBAL) in hexane solution (100
g/liter) and 14.25 g of ethylene-bis-indenyl zirconium dichloride
(EBI). The system was stirred in an atmosphere of N.sub.2 at
20.degree. C. for 1 hour. A clear solution was obtained at the end
of this period.
Preparation of the Catalyst
[0106] A reactor with capacity of 3000 cm.sup.3, equipped with an
anchor stirrer and treated with N.sub.2 at 90.degree. C. for 3
hours, was loaded, at 20.degree. C. in an atmosphere of nitrogen,
with 600 cm.sup.3 of heptane and 60 g of the support previously
prepared. While stirring at 20.degree. C., 900 cm.sup.3 of hexane
solution of TIBAL (100 g/l) were introduced in 30 minutes. The
mixture was heated to 80.degree. C. in 1 hour and was maintained at
this temperature for 2 hours. The mixture was then cooled to
20.degree. C. and 62.5 cm.sup.3 of the TIBAL/EBI solution prepared
previously were introduced. The system was heated to 60.degree. C.
in 30 minutes and was maintained at this temperature for 2 hours.
At the end of this period, 3 washings were effected with hexane at
60.degree. C., removing the solvent by evaporation under vacuum at
the maximum temperature of about 60.degree. C. After drying, about
65 g of catalyst with the following characteristics were obtained:
Zr=0.6%; Mg=15.3%; Cl=48.2%; Al=4.6%;
[0107] Surface area (Hg) 24.1 m.sup.2/g
[0108] Porosity (Hg) 0.359 cm.sup.3/g
[0109] Surface area (BET) 129.2 m.sup.2/g
[0110] Porosity (BET) 0.837 cm.sup.3/g
Polymerization (LLDPE)
[0111] 0.05 g of the catalyst described above was precontacted and
polymerized following the same procedure as in Example 1, using
0.25 bar of H.sub.2 instead of 0.1 bar. At the end, 170 g of
ethylene-butene copolymer were obtained (3400 g copolymer/g cat;
564 kg copolymer/g Zr) with the following characteristics:
MIE=4.76; F/E=32.2; .eta.=1.1; density=0.9135; butene=10.5%;
insoluble in xylene=95%.
Example 5
Preparation of the Catalyst
[0112] A reactor with capacity of 1000 cm.sup.3, equipped with an
anchor stirrer and treated with N.sub.2 at 90.degree. for 3 hours,
was loaded, in an atmosphere of N.sub.2 at 20.degree. C., with 500
cm.sup.3 of toluene and 100 g of the support prepared according to
the procedure in Example 4. While stirring at 20.degree. C., 55 g
of trimethylaluminium (heptane solution 100 g/l) were introduced,
and then the mixture was heated at 105.degree. C. for 3 hours. At
the end the temperature was lowered to 20.degree. C. and 102
cm.sup.3 of the TIBAL/EBI solution prepared according to the
procedure in Example 4 were introduced, then the whole was heated
at 80.degree. C. for 2 hours. After removing the solvent by
evaporation, about 120 g of spherical catalyst with the following
characteristics were obtained: Zr=0.6%; Mg=16.5%; Cl=49.2%;
Al=6.7%;
[0113] Surface area (Hg) 33.8 m.sup.2/g
[0114] Porosity (Hg) 0.495 cm.sup.3/g
[0115] Surface area (BET) 171.3 m.sup.2/g
[0116] Porosity (BET) 0.291 cm.sup.3/g
Polymerization (HDPE)
[0117] 0.05 g of the catalyst described above was precontacted and
polymerized in the same conditions of Example 1, using 0.1 bar of
H.sub.2 instead of 0.25 bar. 115 g of polyethylene (2300 g
polyethylene/g cat) with the following characteristics were
obtained: MIE=0.78; F/E=66.8.
Example 6
Preparation of the Support
[0118] A spherical adduct MgCl.sub.2.3EtOH was prepared following
the procedure described in Example 2 of Patent U.S. Pat. No.
4,399,054, operating at 3000 rpm instead of at 10000 rpm. The
adduct was partially dealcoholized by heating in a stream of
nitrogen at temperatures increasing from 30.degree. C. to
180.degree. C., until an adduct containing 45% by weight of EtOH
was obtained. 2360 g of spherical adduct thus obtained were loaded
into a 30-liter reactor containing 18 liters of hexane. While
stirring at room temperature, 1315 g of AlEt.sub.3 in hexane
solution (100 g/liter) were introduced. The mixture was heated to
60.degree. C. in 60 minutes and was maintained at this temperature
for 60 minutes. The liquid phase was separated and 15 liters of
hexane were introduced. The treatment with AlEt.sub.3 was repeated
twice more operating under the same conditions. At the end, the
spherical support obtained was washed 5 times with hexane and was
dried under vacuum.
Preparation of the Catalyst
[0119] A 1000 cm.sup.3 reactor, equipped with an anchor stirrer and
treated with N.sub.2 at 90.degree. C. for 3 hours, was loaded, in
an atmosphere of nitrogen at 20.degree., with 500 cm.sup.3 of
toluene and 60 g of support. 53.68 cm.sup.3 of the
metallocene/TIBAL solution prepared according to the procedure in
Example 4 were then introduced, stirring continuously for 2 hours
at 20.degree. C. At the end, four washings were effected with
hexane at 20.degree. C., removing the solvent by evaporation under
vacuum. About 62 g of spherical catalyst with the following
characteristics were obtained: Zr=1.1%; Mg=16.6%; Cl=55.3%;
Al=3.6%; OEt=3.2%;
[0120] Surface area (Hg) 38.3 m.sup.2/g
[0121] Porosity (Hg) 0.604 cm.sup.3/g
[0122] Surface area (BET) 298.9 m.sup.2/g
[0123] Porosity (BET) 0.327 cm.sup.3/g
Polymerization (LLDPE)
[0124] 0.05 g of the catalyst described above was polymerized using
the same procedure as in Example 1, obtaining 160 g of
ethylene-butene copolymer (3200 g copolymer/g cat; 290 kg
copolymer/g Zr) with the following characteristics: MIE=1.28;
F/E=50.7; butene=10.5%; .eta.=1.37; insoluble in xylene=95.32%;
density=0.9122.
[0125] The test was repeated using 1.45 g of TIBAL instead of 0.42
g of MAO and 1 bar of H.sub.2 instead of 0.1. 10 g of copolymer was
obtained (200 g copolymer/g cat; 17.3 kg copolymer/g Zr) with
.eta.=0.3.
Example 7
Preparation of the Catalyst
[0126] The catalyst was prepared according to the procedure of
Example 6, except that the four washings with hexane were not
effected at the end of the preparation. About 63 g of spherical
catalyst were obtained, with the following characteristics:
Zr=1.11%; Mg=13%; Cl=44.8%; Al=3.9%; OEt=6.4%;
[0127] Surface area (Hg) 19.7 m.sup.2/g
[0128] Porosity (Hg) 0.476 cm.sup.3/g
[0129] Surface area (BET) 230.2 m.sup.2/g
[0130] Porosity (BET) 0.197 cm.sup.3/g
Polymerization (LLDPE)
[0131] 0.05 g of the catalyst described above was polymerized
according to the methodology described in Example 1, using 1 bar of
H.sub.2 instead of 0.1 and 150 g of butene instead of 100. 330 g of
ethylene-butene copolymer were obtained (6600 g copolymer/g cat;
597 kg copolymer/g Zr), with the following characteristics:
MIE=16.3; F/E=34.6; .eta.=0.76; density=0.9097; Mw/Mn=3.7.
Example 8
Preparation of the Catalyst
[0132] A reactor with capacity of 1000 cm.sup.3, equipped with an
anchor stirrer and treated with N.sub.2 at 90.degree. C. for 3
hours, was loaded, in an atmosphere of N.sub.2 at 20.degree. C.,
with 600 cm.sup.3 of heptane and 60 g of support prepared according
to the methods in Example 6. While stirring at 20.degree. C., 86.4
cm.sup.3 of solution of trimethyl-aluminium (TMA) in hexane (100
g/liter) were introduced in 30 minutes. The system was heated to
80.degree. C. in 1 hour and was maintained at this temperature for
2 hours. The solution was than cooled to 20.degree. C. and 272
cm.sup.3 of EBI/MAO solution prepared according to the procedure of
Example 3 were introduced. The mixture was heated to 60.degree. C.
in 30 minutes and was maintained at this temperature for 2 hours.
At the end of this period the solvent was removed by evaporation
under vacuum at maximum temperature of about 60.degree. C. for
about 3 hours. About 63 g of spherical catalyst with the following
characteristics were obtained: Zr=0.8%; Mg=12.6%; Cl=40%;
Al=9.3%.
Polymerization (LLDPE)
[0133] 0.05 g of the catalyst described above was used for the
preparation of an ethylene-butene copolymer according to the
procedure in Example 1, using 1.45 g of TIBAL instead of 0.42 g of
MAO. At the end, 45 g of copolymer were obtained (900 g copolymer/g
cat; 110 kg copolymer/g Zr), with the following characteristics:
MIE=8.34; F/E=28.91; .eta.=1.15; insoluble in xylene=81.5%;
density=0.905.
Example 9
Preparation of Support
[0134] The support was prepared according to the procedure
described in Example 1.
Preparation of the Catalyst
[0135] In a 1000 cm.sup.3 reactor, equipped with a mechanical
stirrer and pretreated with N.sub.2 at 90.degree. C. for 3 hours,
600 cm.sup.3 of hexane and 120 g of the above described support
were fed at 20.degree. C. under a nitrogen atmosphere; 16.2 g of
isoamyl ether was then added over 30 minutes and the system was
heated to 50.degree. C. and kept at this temperature for 1 hour. At
the end of this period it was cooled to 20.degree. C., 5 g of
ethylene bisindenyl zirconium chloride was added and the whole was
kept stirred for 15 minutes. Then, 15.7 g of diethyl aluminium
monochloride (100 g/l solution in hexane) was added and the mixture
was heated to 40.degree. C. maintaining at this temperature for 1
hour. After this period, the mixture was cooled to 20.degree. C.,
the solid was allowed to settle and the liquid phase was removed.
600 cm.sup.3 of hexane and 15.7 g of AlEt.sub.2Cl were fed and the
above described treatment was repeated. Finally the product was
washed three times with 200 cm.sup.3 of hexane at 60.degree. and
three times with 200 cm.sup.3 of hexane at 20.degree., obtaining
102 g of spherical catalyst component having the following
characteristics: Mg=21.4%; Cl=65.79%; Al=0.3%; Zr=0.67%; isoamyl
ether=2.0%; EtO=3.8%.
Polymerization (HDPE)
[0136] The so obtained catalyst was used to prepare HDPE according
to the process described in Example 2. 240 g of polymer were
obtained (4813 g PE/g catalyst; 780 Kg PE/g Zr) having the
following characteristics: MIE=1.02; F/E=62; .eta.=1.08;
Mw/Mn=2.9.
Example 10
Preparation of Support
[0137] The support was prepared according to the procedure
described in Example 6.
Preparation of the Metallocene/Triisobutylaluminium Solution
[0138] In a 1000 cm.sup.3 reactor, equipped with mechanical stirrer
and purged with nitrogen, 620 cm.sup.3 of triisobutyl aluminium in
hexane solution (100 g/l) and 42 g of
ethylene-bis-4,7-dimethylindenyl zirconium dichloride (EBDMI) were
fed. The reaction was carried out as described in Example 1.
Preparation of the Catalyst
[0139] Into a previously purged 2 l reactor, 250 cm.sup.3 of
heptane and 35 g of the above described support were fed. The
mixture was cooled to 0.degree. C. and 505 cm.sup.3 of TIBAL (100
g/l solution in hexane) were added; the whole was heated to
60.degree. C. for 1 hour and subsequently cooled to 20.degree. C.
31 cm.sup.3 of the above described EBDMI/TIBAL solution was fed and
the mixture was heated to 70.degree. C. for 2 hours, after which it
was cooled to 20.degree. C.; the solid was allowed to settle and
the liquid was siphoned. After drying under vacuum at 50.degree.
C., about 30 g of spherical catalyst was obtained, having the
following characteristics: Mg=15.95%; Cl=54.75%; Al=3.2%; Zr=0.98%;
EtO=7.0%.
Polymerization (LLDPE)
[0140] The so obtained catalyst was used in the preparation of
LLDPE according to example 1, using 1.45 g of TIBAL instead of 0.42
g of MAO. 100 g of copolymer was obtained (g copolymer/g cat=2000;
Kg of copolymer/g Zr=200) having the following characteristics:
MIE=0.48; F/E=45.83; density=0.919; Insolubility in
xylene=98.51%.
Example 11
Preparation of Support
[0141] The support was prepared according to the procedure
described in Example 8.
Preparation of the Metallocene/Methylaluminoxane Solution
[0142] Into a previously purged one liter reactor, 600 cm.sup.3 of
toluene, 76.5 g of methylaluminoxane and 15.6 g of EBDMI were fed;
the system was kept under stirring at 20.degree. C. for 2
hours.
Preparation of the Catalyst
[0143] Into a previously purged 1 liter reactor, 200 cm.sup.3 of
toluene and 100 g of the above described support were added;
subsequently 200 cm.sup.3 of the above described metallocene/MAO
solution was added and the system was heated to 40.degree. C. and
kept stirred at this temperature for 2 hours. Finally the solid was
allowed to settle and the liquid was removed by syphoning. The
obtained sold was then washed four times with 200 cm.sup.3 of
hexane at 20.degree. C. and subsequently dried. 125 g of spherical
catalyst was obtained having the following characteristics:
Cl=45.35%; Mg=16.25%; Al=7.1%; Zr=0.45%.
Polymerization (LLDPE)
[0144] The above described catalyst was used to prepare LLDPE
according to the procedure of example 10. 37.7 g of polymer were
obtained (754 g copolymer/g catalyst; 167 Kg of copolymer/g di Zr)
with the following characteristics: MIE=0.4; F/E=46.25;
Insolubility in xylene=97%; .eta.=1.77; Density=0.913.
* * * * *