U.S. patent application number 16/057201 was filed with the patent office on 2018-12-06 for long chain branched polypropylene.
The applicant listed for this patent is Centre National de la Recherche Scientifique (CNRS), Total Research & Technology Feluy. Invention is credited to Manuela Bader, Jean-francois Carpentier, Katty Den Dauw, Evgueni Kirillov, Christian Lamotte, Olivier Lhost.
Application Number | 20180346618 16/057201 |
Document ID | / |
Family ID | 49876513 |
Filed Date | 2018-12-06 |
United States Patent
Application |
20180346618 |
Kind Code |
A1 |
Bader; Manuela ; et
al. |
December 6, 2018 |
Long Chain Branched Polypropylene
Abstract
A process for preparing a long chain branched polypropylene in
presence of two metallocene-based active catalyst systems is
provided. The polypropylene obtained therefrom has new molecular
architecture and improved elasticity properties. The polypropylene
is further characterized by new signals in its .sup.13C NMR
spectrum.
Inventors: |
Bader; Manuela;
(Villefranche sur Saone, FR) ; Carpentier;
Jean-francois; (Acigne, FR) ; Kirillov; Evgueni;
(Rennes, FR) ; Lhost; Olivier; (Havre, BE)
; Lamotte; Christian; (Arquennes, BE) ; Den Dauw;
Katty; (Woluwe-Saint-Lambert, BE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Total Research & Technology Feluy
Centre National de la Recherche Scientifique (CNRS) |
Seneffe
Paris |
|
BE
FR |
|
|
Family ID: |
49876513 |
Appl. No.: |
16/057201 |
Filed: |
August 7, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15102073 |
Jun 6, 2016 |
10072107 |
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PCT/EP2014/076781 |
Dec 5, 2014 |
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16057201 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 210/06 20130101;
C08F 110/06 20130101; C08F 4/65912 20130101; C08F 4/65927 20130101;
C08F 4/65904 20130101; C08F 110/06 20130101; C08F 2/001 20130101;
C08F 4/65904 20130101; C08F 2500/09 20130101; C08F 2500/15
20130101 |
International
Class: |
C08F 110/06 20060101
C08F110/06; C08F 4/659 20060101 C08F004/659 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 6, 2013 |
EP |
13290301.4 |
Claims
1.-10. (canceled)
11. A long chain branched polypropylene having .sup.13C NMR signals
at .delta. 44.88, 44.74, 44.08 and 31.74 ppm characterized in that
the long chain branched polypropylene further has one or more of
the following .sup.13C NMR signals at .delta. 51.1, 49.0, 38.9,
27.1, 26.6, 24.0, 23.3, 23.0, 22.9 or 19.8 ppm.
12. The long chain branched polypropylene according to claim 11,
characterized in that the long chain branched polypropylene has a
molecular weight M.sub.n of at least 20,000 gmol.sup.-1.
13. The long chain branched polypropylene according to claim 11,
having total long chain branching content higher than 3 per 10,000
C.
14. The long chain branched polypropylene according to claim 11,
wherein the loss angle, .delta., evolution as a function of complex
modulus G* comprises a portion increasing with the complex modulus
in the range of G* greater than 1,000 Pa.
15. The long chain branched polypropylene according to claim 11,
wherein said long chain branched polypropylene has a melting
temperature greater than 135.degree. C.
16. The long chain branched polypropylene according to claim 11,
wherein the long chain branching has at least 420 carbon atoms.
17. An article comprising the long chain branched polypropylene
according to claim 11.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to the field of
polypropylene, and in particular to polypropylene having long chain
branchings. The present invention further relates to a process for
the preparation of said long chain branched polypropylene.
DESCRIPTION OF RELATED ART
[0002] Polypropylene is a commodity polymer well appreciated in
many applications. However, one of the major drawbacks of
polypropylene is the low melt strength of the grades usually
proposed on the market. This has strong implications in the use of
polypropylene: [0003] in blown film market, to avoid bubble
stability issues, high molecular weight polypropylene grades are
used. Due to the associated high viscosity, there are usually
throughput restrictions; [0004] in thermoforming application, when
heating the sheets, sagging is a currently reported problem,
imposing to use appropriate MFI (low MFI values, typically MFI=3
g/10 min.); [0005] foam market is strongly reduced for
polypropylene. Very specific, sophisticated and constraint
processes like "PP expanded bead" technology exist but it is known
that polypropylene foam production is harder than with polyethylene
appropriate grades.
[0006] To improve the melt strength, introduction of long chain
branching in the polymer architecture is often reported in
literature. To do so, several options are known: radical
treatments, copolymerization of propylene with
.alpha.,.omega.-dienes or functional monomer, or formation of
macromers with vinyl end-groups using a metallocene catalyst under
specific reactor conditions followed by copolymerization of
macromers with propylene to get long chain branched
polypropylene.
[0007] The above mentioned options have, however, strong
limitations. Radical treatments are expensive due to the need to
use high content of specific radical initiators like
peroxydicarbonate compounds. Industrial quantities of
.alpha.,.omega.-dienes are not really available. Moreover,
.alpha.,.omega.-dienes remaining on the fluff after polymerization
must be eliminated (which is a difficult and expensive operation)
and recycled.
[0008] The third option, i.e. long chain branching formation via
production of macromers using a given metallocene catalyst followed
by copolymerization of the macromers with propylene in a second
step using the same catalyst are known (Weng et al., Macromolecular
Rapid Communications, 2000, 21, 1103 and Weng et al.,
Macromolecular Rapid Communications, 2001, 22, 1488). The long
chain branching polypropylene, obtained by Weng et al. via a
two-step synthesis with the same catalysts, has specific .sup.13C
NMR features (Weng et al. Macromolecules 2002, 35, 3838-3843). The
authors assigned the resonances at .delta. 44.88, 44.74, 44.08 and
31.74 ppm to the long chain branching. The experimental conditions
disclosed, however, are not interesting from an industrial point of
view. Indeed, the production of macromers at temperature around
120.degree. C. and the macromer isolation before introduction for a
further incorporation in a polypropylene growing chain are often
not optimal or even detrimental for the catalyst activity and an
easy industrial implementation.
[0009] EP 2 196 481 discloses a method for preparing a branched
polypropylene comprising contacting propylene with a first
non-bridged catalyst to form relatively short macromers (about five
units long, cf. scheme 3 of EP 2 196 481) and simultaneously with a
second, bridged catalyst to form a polypropylene backbone
incorporating the macromers as side branches. The melt strength
properties of a thus-produced polypropylene are moderate because of
the low entanglement provided by the relatively short branches. The
catalyst system is even not active in sequential polymerization
with an amount of the first catalyst greater than the amount of the
second catalyst
[0010] DE 44 25 787 discloses a process for the preparation of
polypropylene by polymerization of propylene in presence of a
non-bridge metallocene, i.e. Cp*.sub.2ZrCl.sub.2, and a bridged
metallocene Me.sub.2Si-bis(2-methylindenyl)ZrCl.sub.2.
Polypropylene having low melting point is obtained.
[0011] It is also known from Jungling et al. the preparation of
polymer blends in presence of two catalysts, Cp.sub.2ZrCl.sub.2 and
Me.sub.2C(Cp)(Flu). Polypropylene with long chain branching is not
observed.
[0012] EP 1 422 450 discloses the preparation of branched
polypropylene comprising the formation of macromers from olefin
monomer and the polymerization of propylene in presence of
macromers.
[0013] Hence, there is a need for a cost-competitive way to produce
polypropylene with improved melt strength properties.
[0014] The present invention aims at providing a process and a long
chain branched polypropylene that addresses the above-discussed
drawbacks of the prior art.
SUMMARY OF THE INVENTION
[0015] In a first aspect, the present invention relates to a
process for the preparation of polypropylene having long chain
branchings. Said process comprises the steps of: [0016] (a)
providing in a reactor a first active catalyst system comprising an
activating agent having an alkylating and/or ionizing action and a
first precatalyst of formula (I)
##STR00001##
[0016] wherein M is a group IV transition metal; Q.sup.1 and
Q.sup.2 are identical or different and are independently selected
from the group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl
group, C.sub.6-C.sub.20 aryl group, an anionic ligand or a neutral
ligand capable of coordination by a lone pair of electrons; R'' is
of formula --[Z(R.sup.1)(R.sup.2)].sub.n-- n is an integer between
1 and 5; Z is a carbon or silicon; R.sup.1 and R.sup.2 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.1-C.sub.30 alkenyl groups optionally substituted by one or
more substituents, C.sub.6-C.sub.40 aryl groups optionally
substituted by one or more substituents, or R.sup.1 and R.sup.2
together with the atom Z to which they are attached form a three-
to thirty-membered ring optionally substituted by one or more
substituents; R.sup.3 to R.sup.10 are identical or different and
are independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.30 alkyl groups optionally substituted by one or more
substituents, C.sub.6-C.sub.40 aryl groups optionally substituted
by one or more substituents, or two of the substituents R.sup.3 to
R.sup.6 or R.sup.7 to R.sup.10 attached to a carbon atom positioned
vicinal to each other respectively, form with the carbon atom to
which they are attached a cycloalkenyl or aryl group optionally
substituted by one or more substituents, with the proviso that said
first precatalyst is not [R(2-R'.sub.3Si-Ind).sub.2]MQ.sub.2
wherein R' is alkyl having from 1 to 6 carbon atoms and R is a C-
or Si-bridge between the two indenyl moieties, [0017] (b) injecting
propylene, either before or after or simultaneously with step (a),
to produce polypropylene macromers, [0018] (c) providing a second
active catalyst system comprising a second precatalyst and an
activating agent having an alkylating and/or ionizing action, said
second precatalyst being different from said first precatalyst and
being of formula (I) as defined above without the proviso, [0019]
(d) maintaining under polymerization conditions, [0020] (e)
retrieving a polypropylene having long chain branchings.
[0021] In the present invention, the term macromer is given its
commonly recognized meaning of any polymer or oligomer that has a
functional group that can take part in further polymerization.
Preferably, the polypropylene macromers may have vinyl-terminated
chains and/or vinylidene-terminated chains. The first active
catalyst system is selected such that, in presence of propylene,
polypropylene macromers are produced. The first active catalyst
system is prepared by contacting an activating agent having an
alkylating and/or ionizing action with the first precatalyst. The
second active catalyst system is selected for its macromer
incorporation aptitude. Indeed, the second active catalyst system
produce polypropylene incorporating at least part of the
polypropylene macromers produced by said first active catalyst
system.
[0022] The present process relates to the combined use of two
active catalyst systems, each comprising a precatalyst as defined
herein. The first precatalyst used is capable, when activated with
the activating agent, of producing unsaturated macromers while the
second precatalyst, when activated with the activating agent, is
capable of incorporating the produced macromers in a polypropylene
chain. Compared to the use of one single (pre)catalyst, the linear
viscoelastic properties of the polymer produced according to the
present process highlights a more significant deviation from the
linear grades (free of branchings).
[0023] In a preferred embodiment, steps (a) to (c) are carried out
simultaneously by contacting said first and second precatalysts in
the reactor together with the propylene. The activating agent may
be also added simultaneously to said first and second precatalysts.
Said first and second active catalyst systems may therefore be
prepared simultaneously.
[0024] In a preferred embodiment, said first and second
precatalysts may be of formula (I) as defined above wherein M is
zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2 are identical
or different and are independently selected from the group
consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group;
R'' is of formula --[Z(R.sup.1)(R.sup.2)].sub.n-- wherein n is 1 or
2, Z is a carbon or silicon, and R.sup.1 and R.sup.2 are identical
or different and are independently selected from the group
consisting of hydrogen, C.sub.1-C.sub.6 alkyl group, phenyl group
optionally substituted by one or more substituents.
[0025] In a second aspect of the present invention, a long chain
branched polypropylene is provided. Said long chain branched
polypropylene may have .sup.13C NMR spectrum containing signals at
44.88, 44.74, 44.08 and 31.74 ppm and at least one or more of the
following signals at 51.1, 49.0, 38.9, 27.1, 26.6, 24.0, 23.3,
23.0, 22.9 or 19.8 ppm.
[0026] In a preferred embodiment, said long chain branched
polypropylene may have a loss angle, 8, evolution as a function of
complex modulus G* comprising a portion which increases with the
complex modulus in the range of G* greater than 300 Pa, preferably
500 Pa, more preferably 1,000 Pa.
[0027] Said long chain branched polypropylene may have long chain
branching having a molecular weight Mn of at least 6,000
gmol.sup.-1, preferably at least 7,000 gmol.sup.-1, more preferably
at least 8,000 gmol.sup.-1. Said long chain branching may have at
least 420 carbon atoms, preferably at least 500 carbon atoms, more
preferably at least 600 carbon atoms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] FIG. 1a-c represent the .sup.13C{.sup.1H} NMR spectrum (at
125 MHz, recorded at 130.degree. C. in
1,2,4-trichlorobenzene/C.sub.6D.sub.6) of the polypropylene
obtained according to the present invention, i.e. in presence of
precatalysts 3c/l (a), 3c/3b (b) and 3c/3f (c) respectively.
[0029] FIG. 2 represents the van Gurp-Palmen plot, i.e. the
representation of the loss angle as a function of the complex
modulus G*, of polypropylene according to the present invention and
comparative polypropylenes.
DETAILED DESCRIPTION OF THE INVENTION
[0030] As used herein, the term "alkyl" by itself or as part of
another substituent refers to a hydrocarbyl radical of formula
C.sub.nH.sub.2n+1 wherein n is a number greater than or equal to 1.
Generally, alkyl groups of the present invention comprise from 1 to
30 carbon atoms, preferably from 1 to 20 carbon atoms, more
preferably from 1 to 10 carbon atoms. The term "alkyl" encompasses
linear or branched alkyl. Optionally, the term "alkyl" may
encompass alkyl groups substituted or not by one or more
substituents. When a subscript is used herein following a carbon
atom, the subscript refers to the number of carbon atoms that the
named group may contain. Thus, for example, C.sub.1-C.sub.10 alkyl
means an alkyl of one to ten carbon atoms. For example, the
"C.sub.1-C.sub.10 alkyl" refers but is not limited to methyl,
ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl,
1-pentyl, 2-pentyl, 3-pentyl, i-pentyl, neo-pentyl, t-pentyl,
1-hexyl, 2-hexyl, 3-hexyl, 1-methyl-1-ethyl-n-pentyl,
1,1,2-tri-methyl-n-propyl, 1,2,2-trimethyl-n-propyl,
3,3-dimethyl-n-butyl, 1-heptyl, 2-heptyl,
1-ethyl-1,2-dimethyl-n-propyl, 1-ethyl-2,2-dimethyl-n-propyl,
1-octyl, 3-octyl, 4-methyl-3-n-heptyl, 6-methyl-2-n-heptyl,
2-propyl-1-n-heptyl, 2,4,4-trimethyl-1-n-pentyl, 1-nonyl, 2-nonyl,
2,6-dimethyl-4-n-heptyl, 3-ethyl-2,2-dimethyl-3-n-pentyl,
3,5,5-trimethyl-1-n-hexyl, 1-decyl, 2-decyl, 4-decyl,
3,7-dimethyl-1-n-octyl, 3,7-dimethyl-3-n-octyl.
[0031] As used herein, the term aryl refers to a polyunsaturated,
aromatic hydrocarbyl group having a single ring (i.e. phenyl) or
multiple aromatic rings fused together (e.g. naphtyl) or linked
covalently, typically containing 6 to 40 carbon atoms, preferably 6
to 20 carbon atoms, more preferably 6 to 18 wherein at least one
ring is aromatic. Non-limiting examples of aryl comprise phenyl,
biphenylyl, biphenylenyl, tetralinyl, azulenyl, naphthalenyl,
indenyl, acenaphtenyl, phenanthryl, indanyl, pyrenyl. Optionally,
the term "aryl" encompasses aryl substituted by one or more
substituent(s).
[0032] As used herein, the term cycloalkenyl refers to unsaturated
monocyclic hydrocarbons having one endocyclic double bond.
[0033] Whenever the term "substituted" is used in the present
invention, it is meant to indicate that one or more hydrogen on the
atom indicated in the expression using "substituted" is replaced
with a selection from the indicated group, provided that the
indicated atom's normal valence is not exceeded, and that the
substitution results in a chemically stable compound, i.e. a
compound that is sufficiently robust to survive isolation to a
useful degree of purity from a reaction mixture. Substituents may
be selected from the group comprising halogen, amino, heterocycle,
amido, ether, ester, cyano, oxy derivative.
[0034] The term "halogen" as used herein refers to F, Cl, Br, or I.
The term "cyano" as used herein refers to the group --CN. The term
"amido" as used herein refers to the group --C(O)--NR.sup.aR.sup.b
or --N(R.sup.a)--C(O)--R.sup.b wherein R.sup.a and R.sup.b
independently represents hydrogen, C.sub.3-C.sub.10 cycloalkyl,
C.sub.6-C.sub.18 aryl, C.sub.1-C.sub.15 alkyl, C.sub.3-C.sub.10
heterocycle, C.sub.2-C.sub.15 alkenyl, C.sub.2-C.sub.15 alkynyl, or
R.sup.a and R.sup.b are taken together with the nitrogen atom to
which they are attached to form a three to ten membered
N-heterocycle. The term "heterocycle", as used herein as a
substituent is defined as including an aromatic or non aromatic
cyclic alkyl, alkenyl, aryl or alkynyl moiety as defined herein,
having at least one O, P, S and/or N atom interrupting the
carbocyclic ring structure. The term "ester" refers to the group
--C(O)--O--R.sup.c or --O--C(O)--R.sup.c wherein R.sup.c represents
a moiety selected from the group consisting of hydrogen,
C.sub.3-C.sub.10 cycloalkyl, C.sub.6-C.sub.18 aryl,
C.sub.1-C.sub.15 alkyl, C.sub.3-C.sub.10 heterocycle,
C.sub.2-C.sub.15 alkenyl, C.sub.2-C.sub.15 alkynyl. The term "oxy
derivative", as used herein refers to --O--R.sup.c groups wherein
R.sup.c is as defined above. The term "amino" by itself or as part
of another substituent refers to a group of formula
--N(R.sup.a)(R.sup.b) wherein R.sup.a and R.sup.b are as defined
above. The term "ether" is defined as including a group selected
from C.sub.1-C.sub.50 straight or branched alkyl, or
C.sub.2-C.sub.50 straight or branched alkenyl or alkynyl groups or
a combination of the same, interrupted by one or more oxygen atoms.
The term "alkenyl" as used herein, is defined as including branched
and unbranched, monovalent or divalent unsaturated hydrocarbon
radicals having at least one double bond. The term "alkynyl" as
used herein, is defined as including a monovalent branched or
unbranched hydrocarbon radical containing at least one
carbon-carbon triple bond. The term "three- to thirty-membered
ring" as used herein refers to a three to thirty-membered
carbocyclic ring structure interrupted by Z as defined herein, i.e.
Z is carbon or silicon.
[0035] In a first aspect of the present invention, a process for
the preparation of polypropylene having long chain branchings is
provided. Said process comprises the steps of: [0036] (a) providing
in a reactor a first active catalyst system comprising an
activating agent having an alkylating or ionizing action and a
first precatalyst of formula (I)
##STR00002##
[0036] M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group, an anionic ligand or a neutral ligand
capable of coordination by a lone pair of electrons; R'' is of
formula --[Z(R.sup.1)(R.sup.2)].sub.n-- n is an integer between 1
and 5; Z is a carbon or silicon; R.sup.1 and R.sup.2 are identical
or different and are independently selected from the group
consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups optionally
substituted by one or more substituents, C.sub.1-C.sub.30 alkenyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or R.sup.1 and R.sup.2 together with the atom Z to
which they are attached form a three- to thirty-membered ring
optionally substituted by one or more substituents; R.sup.3 to
R.sup.10 are identical or different and are independently selected
from the group consisting of hydrogen, C.sub.1-C.sub.30 alkyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.6 or
R.sup.7 to R.sup.10 attached to a carbon atom positioned vicinal to
each other respectively, form with the carbon atom to which they
are attached a cycloalkenyl or aryl group optionally substituted by
one or more substituents, with the proviso that said first
precatalyst is not [R(2-R'.sub.3Si-lnd).sub.2]MQ.sub.2 wherein R'
is alkyl having from 1 to 6 carbon atoms and R is a C- or Si-bridge
between the two indenyl moieties, [0037] (b) injecting propylene,
either before or after or simultaneously with step (a), to produce
polypropylene macromers, [0038] (c) providing a second active
catalyst system comprising a second precatalyst and an activating
agent having an alkylating and/or ionizing action, said second
precatalyst being different from said first precatalyst and being
of formula (I) as defined above without the proviso, [0039] (d)
maintaining under polymerization conditions, [0040] (e) retrieving
a polypropylene having long chain branchings.
[0041] Said first precatalyst, when activated, or said first active
catalyst system comprising the same may be capable of producing
polypropylene macromers having vinyl-terminated chains and/or
vinylidene-terminated chains. In a preferred embodiment, the first
precatalyst, when activated, or said first active catalyst system
may produce macromers having at least 10% vinyl- and/or
vinylidene-terminated chains content based on the total amount of
terminated chains of the macromers, preferably at least 30% vinyl-
and/or vinylidene-terminated chains content, more preferably at
least 40%, most preferably at least 50% vinyl- and/or
vinylidene-terminated chains content.
[0042] Said polypropylene macromers may have a molecular weight Mn
of at least 6,000 gmol.sup.-1, preferably at least 7,000
gmol.sup.-1, more preferably at least 8,000 gmol.sup.-1. Said
polypropylene macromers may have at least 420 carbon atoms,
preferably at least 500 carbon atoms, more preferably at least 600
carbon atoms.
[0043] Without being bound by any theory, it is assumed that such
long macromers can be produced thanks to inter alia the bridging
R'' which rigidifies the precatalyst molecule. By contrast, in EP 2
196 481, the first (pre)catalyst is non bridged and it can be seen
in scheme 3 thereof that the side chains are rather short, counting
not more than five repeating units. In paragraph [0018] of EP 2 196
481, a single bridge precatalyst
[R(2-R'.sub.3Si-Ind).sub.2]MQ.sub.2 is mentioned but was not
tested. Furthermore, no mention of any effect of the bridge R on
the final polymer, let alone on the macromers length can be found
in said document.
[0044] In a preferred embodiment, said first precatalyst may be of
formula (IIa-c)
##STR00003##
wherein M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group, an anionic ligand or a neutral ligand
capable of coordination by a lone pair of electrons; R'' is of
formula --[Z(R.sup.1)(R.sup.2)].sub.n-- n is an integer between 1
and 5; Z is a carbon or silicon; R.sup.1 and R.sup.2 are identical
or different and are independently selected from the group
consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups optionally
substituted by one or more substituents, C.sub.1-C.sub.30 alkenyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or R.sup.1 and R.sup.2 together with the atom Z to
which they are attached form a three- to thirty-membered ring
optionally substituted by one or more substituents; R.sup.3 to
R.sup.8, R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl or aryl group
optionally substituted by one or more substituents, with the
proviso that said first precatalyst is not
[R(2-R'.sub.3Si-lnd).sub.2]MQ.sub.2 wherein R' is alkyl having from
1 to 6 carbon atoms and R is a C- or Si-bridge between the two
indenyl moieties.
[0045] Preferably, said first precatalyst may be of formula (IIa)
or (IIc)
##STR00004##
wherein M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group; R'' is of formula
--[Z(R.sup.1)(R.sup.2)].sub.n-- n is an integer between 1 and 3; Z
is a carbon or silicon; R.sup.1 and R.sup.2 are identical or
different and are independently selected from the group consisting
of hydrogen, C.sub.1-C.sub.10 alkyl groups optionally substituted
by one or more substituents, C.sub.1-C.sub.10 alkenyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.12 aryl groups optionally substituted by one or more
substituents, or R.sup.1 and R.sup.2 together with the atom Z to
which they are attached form a three- to thirty-membered ring
optionally substituted by one or more substituents; R.sup.3 to
R.sup.8, R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl or aryl group
optionally substituted by one or more substituents.
[0046] More preferably, said first precatalyst may be of formula
(IIa)
##STR00005##
wherein M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group; R'' is of formula
--[Z(R.sup.1)(R.sup.2)].sub.n-- n is 1 or 2; Z is a carbon or
silicon; R.sup.1 and R.sup.2 are identical or different and are
independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.10 alkyl groups optionally substituted by one or more
substituents, C.sub.1-C.sub.10 alkenyl groups optionally
substituted by one or more substituents, C.sub.6-C.sub.12 aryl
groups optionally substituted by one or more substituents; R.sup.3
to R.sup.8, R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl or aryl group
optionally substituted by one or more substituents.
[0047] Most preferably, said first precatalyst may be of formula
(IIa)
##STR00006##
wherein M is zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2
are identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group; R'' is of formula
--[Z(R.sup.1)(R.sup.2)].sub.n-- wherein n is 1 or 2, Z is a carbon
or silicon, and R.sup.1 and R.sup.2 are identical or different and
are independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.6 alkyl groups, C.sub.1-C.sub.6 alkenyl, phenyl group
optionally substituted by one or more substituents, R.sup.3 to
R.sup.6 and R.sup.30 to R.sup.33 are identical or different and are
independently selected from the group consisting of hydrogen,
C.sub.1-C.sub.10 alkyl groups optionally substituted by one or more
substituents, C.sub.1-C.sub.10 alkenyl groups optionally
substituted by one or more substituents, C.sub.6-C.sub.18 aryl
groups optionally substituted by one or more substituents, or two
of the substituents R.sup.3 to R.sup.6 and R.sup.30 to R.sup.33
attached to a carbon atom positioned vicinal to each other
respectively, form with the carbon atom to which they are attached
a cycloalkenyl or aryl group optionally substituted by one or more
substituents.
[0048] In particular, said first precatalyst is of formula
(III)
##STR00007##
wherein M is zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2
are identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.12 aryl group; R.sup.1 is hydrogen, C.sub.1-C.sub.6
alkyl groups, phenyl group optionally substituted by one or more
substituents, R.sup.2, R.sup.3, R.sup.5, are each, independently
from one another, hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, R.sup.30, R.sup.31, R.sup.32, R.sup.33 are each,
independently from one another, hydrogen, C.sub.1-C.sub.30 alkyl
groups optionally substituted by one or more substituents,
C.sub.1-C.sub.30 alkenyl groups optionally substituted by one or
more substituents, C.sub.6-C.sub.40 aryl groups optionally
substituted by one or more substituents, or R.sup.30 and R.sup.31
or R.sup.32 and R.sup.33 form with the carbon atom to which they
are attached a cycloalkenyl or aryl group optionally substituted by
one or more substituents.
[0049] More particularly, said first precatalyst may be of formula
(III)
##STR00008##
wherein M is zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2
are identical and are halogen, R.sup.1 is hydrogen, C.sub.1-C.sub.6
alkyl groups or phenyl group optionally substituted by one or more
substituents, preferably hydrogen; R.sup.2 is C.sub.1-C.sub.6 alkyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.18 aryl groups optionally substituted by one or more
substituents, preferably phenyl group optionally substituted by one
or more substituents; R.sup.3, R.sup.5, are each, independently
from one another, hydrogen, C.sub.1-C.sub.6 alkyl groups optionally
substituted by one or more substituents, C.sub.6-C.sub.12 aryl
groups optionally substituted by one or more substituents;
preferably R.sup.3, R.sup.5, are each, independently from one
another, C.sub.1-C.sub.6 alkyl groups or C.sub.6-C.sub.12 aryl
groups; R.sup.30, R.sup.31, R.sup.32, R.sup.33 are each,
independently from one another, hydrogen, C.sub.1-C.sub.6 alkyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.12 aryl groups optionally substituted by one or more
substituents, or R.sup.30 and R.sup.31 or R.sup.32 and R.sup.33
form with the carbon atom to which they are attached a cycloalkenyl
group optionally substituted by one or more substituents.
[0050] Most particularly, said first precatalyst may be selected
from the group consisting of:
##STR00009## ##STR00010##
[0051] Said second precatalyst is different from said first
precatalyst. Said second precatalyst, when activated, or said
second active catalyst system may be capable of incorporating a
vinyl-terminal and/or vinylidene-terminal macromers in a
polypropylene chain.
[0052] In a preferred embodiment, said second precatalyst may be of
formula (IIa-c)
##STR00011##
wherein M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group, an anionic ligand or a neutral ligand
capable of coordination by a lone pair of electrons; R'' is of
formula --[Z(R.sup.1)(R.sup.2)].sub.n-- n is an integer between 1
and 5; Z is a carbon or silicon; R.sup.1 and R.sup.2 are identical
or different and are independently selected from the group
consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups optionally
substituted by one or more substituents, C.sub.1-C.sub.30 alkenyl
groups optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or R.sup.1 and R.sup.2 together with the atom Z to
which they are attached form a three- to thirty-membered ring
optionally substituted by one or more substituents; R.sup.3 to
R.sup.8, R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.30 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.28 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl or aryl group
optionally substituted by one or more substituents.
[0053] Preferably, said second precatalyst may be of formula (IIa)
or (IIb)
##STR00012##
wherein M is a group IV transition metal; Q.sup.1 and Q.sup.2 are
identical or different and are independently selected from the
group consisting of amido, halogen, C.sub.1-C.sub.10 alkyl group,
C.sub.6-C.sub.20 aryl group; R'' is of formula
--[Z(R.sup.1)(R.sup.2)].sub.n-n is an integer between 1 and 3; Z is
a carbon or silicon; R.sup.1 and R.sup.2 are identical or different
and are independently selected from the group consisting of
hydrogen, C.sub.1-C.sub.10 alkyl groups optionally substituted by
one or more substituents, C.sub.1-C.sub.10 alkenyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.12 aryl groups optionally substituted by one or more
substituents; R.sup.3 to R.sup.8, R.sup.13 to R.sup.20 and R.sup.30
to R.sup.33 are identical or different and are independently
selected from the group consisting of hydrogen, C.sub.1-C.sub.30
alkyl groups optionally substituted by one or more substituents,
C.sub.6-C.sub.40 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.20 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl or aryl group
optionally substituted by one or more substituents.
[0054] More preferably, said second precatalyst may be of formula
(IIa) or (IIb)
##STR00013##
wherein M is zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2
are halogen; R'' is of formula --[Z(R.sup.1)(R.sup.2)].sub.n--
wherein n is 1 or 2, Z is a carbon or silicon, and R.sup.1 and
R.sup.2 are identical or different and are independently selected
from the group consisting of hydrogen, C.sub.1-C.sub.6 alkyl
groups, C.sub.1-C.sub.6 alkenyl groups, phenyl group optionally
substituted by one or more substituents, preferably R.sup.1 and
R.sup.2 are identical or different and are independently selected
from the group consisting of hydrogen, methyl, ethyl and phenyl
group optionally substituted by one or more substituents, R.sup.3
to R.sup.8, R.sup.13 to R.sup.20 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.10 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.12 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.3 to R.sup.8,
R.sup.13 to R.sup.20 and R.sup.30 to R.sup.33 attached to a carbon
atom positioned vicinal to each other respectively, form with the
carbon atom to which they are attached a cycloalkenyl optionally
substituted by one or more substituents.
[0055] More preferably, said second precatalyst is of formula (III)
or (IV)
##STR00014##
wherein M is zirconium, hafnium or titanium; Q.sup.1 and Q.sup.2
are halogen; R'' is of formula --[Z(R.sup.1)(R.sup.2)].sub.n--
wherein n is 1 or 2, Z is a carbon or silicon, and R.sup.1 and
R.sup.2 are identical or different and are independently selected
from the group consisting of hydrogen, C.sub.1-C.sub.6 alkyl
groups, C.sub.1-C.sub.6 alkenyl groups, phenyl group optionally
substituted by one or more substituents, preferably R.sup.1 and
R.sup.2 are identical or different and are independently selected
from the group consisting of hydrogen, methyl, ethyl and phenyl
group optionally substituted by one or more substituents; R.sup.3,
R.sup.5, R.sup.7, R.sup.13, R.sup.17 and R.sup.30 to R.sup.33 are
identical or different and are independently selected from the
group consisting of hydrogen, C.sub.1-C.sub.10 alkyl groups
optionally substituted by one or more substituents,
C.sub.6-C.sub.18 aryl groups optionally substituted by one or more
substituents, or two of the substituents R.sup.30 to R.sup.33
attached to a carbon atom positioned vicinal to each other
respectively, form with the carbon atom to which they are attached
a cycloalkenyl optionally substituted by one or more
substituents.
[0056] In particular, said second precatalyst, being different from
said first precatalyst, may be selected from the group consisting
of:
##STR00015## ##STR00016## ##STR00017##
First and second precatalysts could be selected from the same
families but they must be different. As mentioned above, the first
precatalyst will be selected for its macromer production aptitude
whereas the second one will be selected for its macromer
incorporation aptitude.
[0057] In the present process, the first and second precatalysts
may be introduced in the reactor either simultaneously or
sequentially.
[0058] In a preferred embodiment, step (c) is carried out
sequentially after step (b) without isolation of the product formed
in step (b), preferably step (c) is carried out at least 10 minutes
after step (b), more preferably at least 20 minutes after step (b),
most preferably at least 30 minutes after step (b).
[0059] In another preferred embodiment, steps (a) to (c) are
carried out simultaneously by injecting or providing said first and
second active catalyst systems into the reactor. Hence, the present
process may comprise the steps of providing in a reactor said first
and second active catalyst systems as defined above, contacting
them with propylene, maintaining under polymerization conditions
and retrieving a polypropylene having long chain branching. Said
first and second active catalyst systems may also be prepared in
situ. Hence, the present process may comprise the steps of
providing in a reactor said first and second precatalysts as
defined above with the proviso than said second precatalyst is
different from said first precatalyst, contacting said first and
second precatalyst with propylene in presence of an activating
agent having an alkylating and/or ionizing action, maintaining
under polymerization conditions and retrieving a polypropylene
having long chain branching.
[0060] Said first active catalyst system may be contacted with
propylene at a temperature at which polypropylene macromers having
vinyl- or vinylidene-terminated chains can be produced therewith.
Preferably, said first active catalyst system may be contacted with
propylene at temperature of at least 40.degree. C., more preferably
of at least 60.degree. C., most preferably of at least 80.degree.
C. In particular, said first precatalyst may be contacted with
propylene at temperature ranging from 40.degree. C. to 100.degree.
C., preferably from 50.degree. C. to 90.degree. C., more preferably
from 60.degree. C. to 80.degree. C.
[0061] The weight ratio between the first precatalyst and the
second precatalyst, or between the first active catalyst system and
the second active catalyst system, is of 1/2 to 100/1, preferably
of 1/1 to 50/1, more preferably of 2/1 to 15/1, most preferably of
5/1 to 10/1.
[0062] In a preferred embodiment, the activating agent is selected
from alkyl aluminium, alumoxanes and boron-containing compounds.
The activating agent used to prepare said first active catalyst
system may be the same or different from the activating agent used
to prepare said second active catalyst system.
[0063] The activating agent can be an alkyl aluminium represented
by formula AIR*.sub.nX.sub.3-n wherein R* is an alkyl having from 1
to 20 carbon atoms, n is an integer between 0 and 3 and X is a
halogen. The preferred alkyl aluminium may be triisobutylaluminium
(TIBAL) or triethylaluminium (TEAL). The alkyl aluminium can be
used in combination with a perfluoroborate e.g.
[Ph.sub.3C][B(C.sub.6F.sub.5).sub.4] or
[Me.sub.2NPhH][B(C.sub.6F.sub.5).sub.4]. For example, using a
combination of [Ph.sub.3C][B(C.sub.6F.sub.5).sub.4]/TIBAL or of
[Me.sub.2NPhH][B(C.sub.6F.sub.5).sub.4]/TIBAL.
[0064] Suitable boron-containing agents may also be used for
activating the metallocene compound to form a precatalyst system.
These include for example a triphenylcarbenium boronate such as
tetrakis(pentafluorophenyl)borato-triphenylcarbenium as described
in EP-A-0427696, or those of the general formula
[L'-H]+[BAr.sup.1Ar.sup.2X.sup.3X.sup.4]-- as described in
EP-A-0277004 (page 6, line 30 to page 7, line 7). The amount of
boron-containing activating agent is selected to give a B/M ratio
of from 0.5 to 5, preferably of about 1.
[0065] The activating agent may be an aluminoxane and may comprise
oligomeric linear and/or cyclic alkyl aluminoxanes represented by
formula
##STR00018##
for oligomeric, linear aluminoxanes and by formula
##STR00019##
for oligomeric, cyclic aluminoxane, wherein n is 1-40, preferably
1-20, m is 3-40, preferably 3-20 and R* is a C.sub.1-C.sub.8 alkyl
group and preferably methyl or isobutyl. Preferably, the activating
agent is selected from methylaluminoxane (MAO) and
ethylaluminoxane. More preferably the activating agent is MAO. The
amount of activating agent is selected to give an AI/M ratio of 10
to 10,000, preferably 100 to 10,000, more preferably of 200 to
4,000, even more preferably from 500 to 3,000, most preferably from
to 1,000 to 3,000. The amount of activating agent depends upon its
nature.
[0066] The catalyst system may comprise a scavenger that may be
selected from the group consisting of alkyl aluminium represented
by formula AIR*.sub.nX.sub.3-n wherein R* is an alkyl having from 1
to 20 carbon atoms, n is an integer between 0 and 3 and X is a
halogen; or aluminoxane. Said scavenger may be, for example,
triethylaluminium, triisobutylaluminum, tris-n-octylaluminium,
tetraisobutyldialuminoxane, diethylzinc, tris-n-hexyl aluminium,
diethylchloroaluminum or MAO. Usually, the scavenger is added after
activation of the precatalyst with the activating agent.
Preferably, the scavenger is different from the activating
agent.
[0067] In another embodiment, the catalyst system according to the
invention further comprises an inorganic support. The inorganic
support may comprise talc, inorganic oxides, clays and clay
minerals, ion-exchanged layered compounds, diatomaceous earth
compounds, zeolites or a resinous support material, such as a
polyolefin, for example. Specific inorganic oxides include silica,
alumina, magnesia, titania and zirconia, for example. Preferably,
the inorganic support may comprise silica and/or alumina. The
inorganic support may comprise from 10 to 100 wt % of silica and/or
preferably from 10 to 100 wt % of alumina.
[0068] Alternatively, the inorganic support may also be an
activating support such as fluorinated alumina silica. Methods for
preparing such inorganic supports are described WO 2007/127465 or
WO2005/075525.
[0069] Preferably, the inorganic support is pre-impregnated with
MAO before adding the metallocene compound.
[0070] The pressure in the reactor can vary from 0.5 to 50 bars,
i.e. from 510.sup.4 Pa to 510.sup.6 Pa, preferably from 5 to 25
bars, i.e. from 510.sup.6 Pa to 2.510.sup.6 Pa.
[0071] Optionally hydrogen can be added to control the molecular
weight of the polypropylene. Also optionally, an anti-fouling agent
can be added to the reactor.
[0072] The polymerisation process can be carried out in solution,
in slurry or in gas phase. In a slurry process, the first and/or
second precatalysts or the first and/or second active catalyst
systems are preferably supported. The slurry process can be carried
out in a reactor suitable for such processes, such as continuously
stirred tank reactors (CSTRs) or slurry loop reactors (in
particular liquid full loop reactors).
[0073] Two or more reactors may be connected in series in order to
produce bimodal copolymers. The pressure in each reactor can vary
from 0.5 to 50 bars, i.e. from 510.sup.4 Pa to 510.sup.6 Pa,
preferably 5 to 25 bars, i.e. from 510.sup.5 Pa to 2.510.sup.6 Pa,
most preferably may be around 20 bars, i.e. 2.10.sup.6 Pa. The
amount of hydrogen, the temperature or the content of propylene in
the feed can be different in each reactor. Preferably, the active
catalyst systems used in each reactor may be the same or different.
The long chain branching content of the polypropylene produced in
each reactor can be different as well as the molecular weight.
Preferably, an overlap of the molecular weight distribution of
polypropylene produced in each reactor is obtained. The molecular
weight distribution may range from 1 to 7 for the polypropylene
produced in each reactor, preferable from 1.5 to 4.0.
[0074] Long chain branched polypropylene can be obtained with the
present process in the slurry, gas phase or solution phase, using a
heterogeneous (supported) catalyst system or a homogeneous
(unsupported) catalyst system. A diluent or solvent may be used in
the present process. Said diluent or solvent may be a hydrocarbon,
preferably a saturated hydrocarbon having from 4 to 12 carbon
atoms, such as isobutane or hexane. Alternatively, said diluent or
solvent may be unsaturated hydrocarbon such as toluene.
[0075] In a second aspect of the present invention, a long chain
branched polypropylene is provided. As already disclosed by Weng et
al., a first type of the long chain branched polypropylene has
.sup.13C NMR signals at .delta. 44.88, 44.74, 44.08 and 31.74 ppm.
According to the present invention, a second type of long chain
branching is also incorporated in the long chain branched
polypropylene which has one or more of the following .sup.13C NMR
signals: .delta. 51.1, 49.0, 38.9, 27.1, 26.6, 24.0, 23.3, 23.0,
22.9 or 19.8 ppm. In a preferred embodiment, the long chain
branched polypropylene may have two, three, four, five, six, seven,
eight, nine or ten of the following .sup.13C NMR signals: .delta.
51.1, 49.0, 38.9, 27.1, 26.6, 24.0, 23.3, 23.0, 22.9 or 19.8 ppm.
In particular, the long chain branched polypropylene has .sup.13C
NMR signals at .delta. 19.8, 22.9, 23.0, 23.3, 24.0, 26.6, 27.1,
31.74, 38.9, 44.08, 44.74, 44.88, 49.0 and 51.1 ppm.
[0076] The long chain branched polypropylene may be isotactic or
syndiotactic. The tacticity of the said long chain branched
polypropylene may be controlled by the first and/or second active
catalyst systems used in the process according to the present
invention. As the second active catalyst systems are the ones which
make the polypropylene backbone, the tacticity of the said long
chain branched polypropylene may be preferably controlled by said
second active catalyst systems. Preferably, the long chain branched
polypropylene may be isotactic when the second active catalyst
system comprises a second precatalyst of formula (3a), (3b), (3c),
(3d), (3e), (3f), (3g), (3h), (3i) or (3j). The tacticity of the
long chain branched polypropylene may be further increased by
providing isotactic long chain branching, e.g. isotactic
polypropylene macromers, for example by using a first active
catalyst system comprising a first precatalyst of formula (III) as
defined above wherein R.sup.3 and R.sup.5 are not simultaneously
hydrogen. The tacticity of the said long chain branched
polypropylene may be at least 70% mmmm, preferably at least 80%
mmmm. In particular, the tacticity of the said long chain branched
polypropylene may range from 80% to 95% mmmm. Alternatively, the
long chain branched polypropylene may be syndiotactic. The
tacticity of the said long chain branched polypropylene may be at
least 70% rrrr, preferably at least 80% rrrr. In particular, the
tacticity of the said long chain branched polypropylene may range
from 80% to 95% rrrr. A syndiotactic long branched polypropylene
may be obtained with a second active catalyst system comprising a
second precatalyst such as for example a precatalyst of formula
(III) wherein R.sup.3 and R.sup.5 are hydrogen. The tacticity of
the long chain branched polypropylene may be further increased by
providing syndiotactic long chain branchings, e.g. syndiotactic
polypropylene macromers, for example by using a first active
catalyst system comprising a first precatalyst of formula (III) as
defined above wherein R.sup.3 and R.sup.5 are not simultaneously
hydrogen with the proviso that the first and second precatalysts
are different.
[0077] The long chain branched polypropylene obtained at the end of
the present process may have molecular weight Mn of at least 20,000
gmol.sup.-1, preferably ranging from 30,000 to 1,000,000
gmol.sup.-1, preferably from 30,000 to 750,000 gmol.sup.-1, more
preferably from 30,000 to 500,000 gmol.sup.-1. The long chain
branched polypropylene according to the present invention
incorporates propylene macromers, preferably having Mn greater than
6,000 gmol.sup.-1, more preferably greater than 7,000
gmol.sup.-1.
[0078] The long chain branched polypropylene may have
polydispersity Mw/Mn ranging from 1.0 to 20.0, preferably from 1.5
to 5.0, more preferably from 2.0 to 4.0 determined as disclosed in
the tests methods.
[0079] The long chain branched polypropylene according to the
present invention may also have melting temperature of at least 115
C, preferably 135.degree. C., more preferably at least 140.degree.
C.
[0080] The long chain branching polypropylene have excellent melt
strength behavior. The use of first and second active catalyst
system comprising said first and second precatalysts respectively
according to the present process allows the long chain branched
polypropylene having more significant rheological linear
viscoelastic deviations from the linear case. The long chain
branched polypropylene according to the present invention may have
a loss angle, 8, evolution as a function of complex modulus G*
comprising a portion which increases with the complex modulus in
the range of G* greater than 300 Pa, preferably 500 Pa, more
preferably 1,000 Pa, even more preferably greater than 5,000
Pa.
[0081] In particular, a long chain branched polypropylene having
loss angle, 8, lower than 70.degree., preferably lower than
60.degree., more preferably lower than 55.degree., at complex
modulus G* ranging from 1000 Pa to 10,000 Pa.
[0082] The branching of said polypropylene, typically the chains
produced during polymerization induced by the first precatalyst,
according to the present invention may have a molecular weight Mn
of at least 6,000 gmol.sup.-1, preferably at least 7,000
gmol.sup.-1, more preferably at least 8,000 gmol.sup.-1. Said
branching may have at least 420 carbon atoms, preferably at least
500 carbon atoms, more preferably at least 600 carbon atoms.
[0083] The long chain branched polypropylene has at least two
different types of long chain branching as suggested by the
.sup.13C NMR spectrum. A first type of long chain branchings are
similar to the long chain branchings disclosed by Weng et al. Such
type of branchings is characterized by signals in .sup.13C NMR
spectrum at .delta. 44.88, 44.74, 44.08 and 31.74 ppm. The content
of long chain branchings in the polypropylene according to this
first type of long chain branchings may be greater than 0.2 per
10,000 C, preferably greater than 0.3 per 10,000 C, more preferably
greater than 0.5 per 10,000 C. The second type of long chain
branching which has never been disclosed before in the prior art is
characterized by new .sup.13C NMR signals as described above. The
content of long chain branchings in the polypropylene according to
this second type of long chain branchings may be greater than 0.2
per 10,000 C, preferably greater than 0.3 per 10,000 C, more
preferably greater than 0.5 per 10,000 C. The total content of long
chain branchings (i.e. first type+second type of long chain
branchings as disclosed herein) of the polypropylene according to
the present invention may be greater than 0.2 per 10,000 C,
preferably greater than 0.5 per 10,000 C, more preferably greater
than 0.6 per 10,000 C, most preferably greater than 1.0 per 10,000
C. Hence, according to the present process, a new long chain
branched polypropylene is produced having a new type of branchings
which are different from the ones disclosed in the art.
[0084] In another aspect, the present invention relates to an
article comprising polypropylene according to the present
invention.
[0085] Test Methods
[0086] Molecular weights were determined by Size Exclusion
Chromatography (SEC) at high temperature (145.degree. C.). A 10 mg
polymer sample was dissolved at 160.degree. C. in 10 mL of
trichlorobenzene (technical grade) for 1 hour. Analytical
conditions for the CPVIR5 from PolymerChar were: [0087] Injection
volume: +/-400 .mu.L [0088] Automatic sample preparation and
injector temperature: 160.degree. C. [0089] Column temperature:
145.degree. C. [0090] Detector temperature: 160.degree. C. [0091]
Column set: 2 Shodex AT-806MS and 1 Styragel HT6E [0092] Flow rate:
1 ml/min [0093] Detector: Infrared detector (2,800-3,000 cm.sup.1)
[0094] Calibration: Narrow standards of polystyrene (commercially
available) [0095] Calculation for polypropylene: Based on
Mark-Houwink relation
(log.sub.10(M.sub.PP)=log.sub.10(Mps)-0.25323); cut off on the low
molecular weight end at M.sub.PP=1000.
[0096] The molecular weight distribution (MWD) or polydispersity
(P) was then calculated as M.sub.w/M.sub.n.
[0097] Melting temperatures T.sub.melt and crystallization
temperatures T.sub.cryst were determined according to ISO 3146 on a
DSC Q2000 instrument by TA Instruments. To erase the thermal
history, the samples were first heated to 200.degree. C. and kept
at 200.degree. C. for a period of 3 minutes. The reported melting
temperatures T.sub.melt and T.sub.cryst were then determined with
heating and cooling rates of 20.degree. C./min.
[0098] The .sup.13C NMR analysis was performed at an operative
frequency of 125 MHz using a 500 MHz Bruker NMR spectrometer with a
high temperature 10 mm cryoprobe under conditions such that the
signal intensity in the spectrum is directly proportional to the
total number of contributing carbon atoms in the sample. Such
conditions are well known to the skilled person and include for
example sufficient relaxation time etc. In practice, the intensity
of a signal is obtained from its integral, i.e. the corresponding
area. The data were acquired using proton decoupling, 240 scans per
spectrum, a pulse repetition delay of 11 seconds and a spectral
width of 26,000 Hz at a temperature of 130.degree. C. The sample
was prepared by dissolving a sufficient amount of polymer in
1,2,4-trichlorobenzene (TCB, 99%, spectroscopic grade) at
130.degree. C. and occasional agitation to homogenize the sample,
followed by the addition of hexadeuterobenzene (C.sub.6D.sub.6,
spectroscopic grade) and a minor amount of hexamethyldisiloxane
(HMDS, 99.5+%), with HMDS serving as internal standard. To give an
example, about 200 mg of polymer were dissolved in 2.0 mL of TCB,
followed by addition of 0.5 mL of C.sub.6D.sub.6 and 2 to 3 drops
of HMDS. Prior to Fournier Transform, Lorentz-Gauss transformation
(Lb=-0.2, Gb=0.02) is applied to improve sensitivity and
resolution. The chemical shifts are referenced to the signal of the
internal standard HMDS, which is assigned a value of b 2.03
ppm.
[0099] The long chain branching content of the first type of
branching as disclosed by Weng et al. (per 10,000 carbon atoms) is
determined from CH (at .delta. 31.8 ppm) area divided by the sum of
all peaks area, multiplied by 10,000. The long chain branching
content of the second type of branching according to the present
invention (per 10,000 carbon atoms) is determined from average of
additional peaks (newly observed and disclosed above) area divided
by the sum of all peaks area, multiplied by 10,000.
[0100] The isotacticity was determined by .sup.13C NMR analysis on
the total polymer. In the spectral region of the methyl groups, the
signals corresponding to the pentads mmmm, mmmr, rmmr, mmrr,
rmrr+mrmm, mrmr, rrrr, mrrr and mrrm were assigned using published
data, for example A. Razavi, Macromol. Symp., 1995, vol. 89, pages
345-367. Some area corrections were performed in case of overlap
with signals related to 2,1-insertions, 1,3-additions, n-propyl
chain ends, etc. The percentage of mmmm pentads was then calculated
by normalization of all the methyl pentads area according to
%
mmmm=AREA.sub.mmmm/(AREA.sub.mmmm+AREA.sub.mmmr+AREA.sub.mmrr+AREA.sub-
.mrrm)*100.
The .sup.13C NMR detection limit in these conditions is about
0.6/10,000 C.
[0101] G' (storage modulus) and G'' (loss modulus) were measured at
a temperature of 230.degree. C. using a dynamic rheometer in a
frequency sweep with a strain of 20% on an ARES-G2 instrument from
TA, branch of WATERS.
Examples
[0102] The comparative example is carried out in presence of a
single precatalyst. The polymerization tests are carried out in a
300 mL high-pressure glass reactor equipped with a mechanical
stirrer (Pelton turbine) and externally heated with a double mantle
with a thermostated circulating water bath. The reactor was charged
with toluene (150 mL) and MAO (1.5 mL of a 30 wt % solution in
toluene, Albemarle), and propylene (5 bar, Air Liquide, 99.99%) was
introduced. The reactor was thermally equilibrated at the desired
temperature (60.degree. C.) for 30 min. Propylene pressure was
decreased to 1 bar, and a solution of the precatalyst, for example
[PhCH-(3,6-tBu.sub.2-Flu)(3-tBu-5-Et-Cp)]ZrCl.sub.2 (3b) (1.0 mg)
in toluene (ca. 2 mL) was added by syringe. The propylene pressure
was immediately increased to 5 bar (and then kept constant with a
back regulator throughout the polymerization reaction) and the
solution was stirred for the desired time (30 min). The temperature
in the reactor was monitored using a thermocouple. The
polymerization was stopped by venting the vessel ad quenching with
a 10 wt % solution of aqueous HCl in methanol (ca. 3 mL). The
polymer was precipitated in methanol (ca. 200 mL) and 35 wt %
aqueous HCl (ca. 1 mL) was added to dissolve possible precatalyst
residues. The polymer was collected by filtration, washed with
methanol (ca. 200 mL), and dried under vacuum overnight.
[0103] Inventive example according to the process of the present
invention was carried out in the same reactor as in comparative
example. The reactor was charged with toluene (150 mL) and MAO (1.5
mL of a 30 wt % solution in toluene, Albemarle), and propylene (5
bar, Air Liquide, 99.99%) was introduced. The reactor was thermally
equilibrated at the desired temperature (80.degree. C.) for 30 min
before decreasing the propylene pressure to 1 bar. A solution of
the first precatalyst, for example
[PhCH-(3,6-tBu.sub.2-Flu)(3-tBu-5-Ph-Cp)]ZrCl.sub.2 (3c) (10 mg) in
toluene (3 mL) was added by syringe. The propylene pressure was set
to 5 bar. After 30 min reaction, the reactor was cooled to
60.degree. C. and vented before adding a solution of the second
precatalyst, for example
[PhCH-(3,6-tBu.sub.2-Flu)(3-tBu-5-Et-Cp)]ZrCl.sub.2 (3b) (1.0 mg)
in toluene (ca. 1 mL). The propylene pressure was increased to 5
bar and the solution was stirred for 30 additional min before
venting the reactor, quenching the reaction (3 mL of a 10 wt %
solution of aqueous HCl in methanol) and cooling the reactor to
25.degree. C. The polymer was precipitated in methanol (ca. 200 mL)
and 35 wt % aqueous HCl (ca. 1 mL) was added to dissolve possible
catalyst residues. The polymer was collected by filtration, washed
with methanol (ca. 200 mL), and dried under vacuum overnight.
Extraction of the oligomeric fractions was performed using n-hexane
in a Kumagawa reactor. The insoluble fraction properties were
analyzed by rheological methods. The present process may also be
carried out by introducing in the reactor the two precatalysts
simultaneously.
[0104] The advantages of the present invention are illustrated by
the following representative examples. Table 1 reports experimental
conditions of comparative and inventive examples wherein
precatalysts 3j, 3b, 3c and 3f as defined above were used. Table 1
also reports physical properties of the polypropylene obtained
therewith. It is clearly demonstrated that the use of two
precatalysts allows the formation of a polypropylene having long
chain branchings while the process carried out in presence of only
one precatalyst does not lead to the formation of a long chain
branched polypropylene.
TABLE-US-00001 TABLE 1 1.sup.st/2.sup.nd Zr.sub.1/Zr.sub.2
Al/Zr.sub.1 & AL/Zr.sub.2 Tpoly Prod.sub.1 Prod.sub.2 Mn.sup.a
M.sub.w/ T.sub.m Tacticity.sup.b LCB.sup.c catalyst [.mu.mol
L.sup.-1] [.mu.mol L.sup.-1] (.degree. C.) [g.sub.pp
g.sub.cat.sup.-1] [g.sub.pp g.sub.cat.sup.-1] [kg mol.sup.-1]
M.sub.n (.degree. C.) [m.sup.4] (%) [/10.000C] 3c 97 2000 80 900 --
6.1 1.6 -- 19.4 0 3j 2.9 15500 60 -- 90.100 41.2 2.1 155 97.7 0
3c/3j 89/4 1040/22350 80/60 760 68.850 26.4 2.3 143 85.3 5.6 3c/3j
49/4 1110/14460 80/60 600 61.570 nd nd 144 nd nd 3b 10 5000 60 --
11.430 62.5 2.0 148 92.2 0 3c/3b 95/12 1900/15250 80/60 1.370 6.640
28.6 1.9 140 76.3 nd 3c/3b 95/12 1310/10170 60/60 1.540 1.850 32.5
2.4 142 81.2 0.9 3c/3b 33/10 1810/6120 80/80. 1.860 7.120 31.6 2.5
142 80.7 0.9 3f 8 5000 60 -- 16.700 61.3 2.3 152 94.1 0 3c/3f 91/8
1190/10630 80/60 1.130 6.280 nd nd 144 82.0 0.9 3c/3f 98/10 430/380
90/60 620 3.640 nd nd 145 nd nd n.d. = not determined * Both
catalyst were charged simultaneously; .sup.adetermined by GPC;
.sup.bdetermined by .sup.13C NMR; .sup.cdetermined by 13C NMR and
corresponding to the long chain branching content of branching as
disclosed by Weng et al.
TABLE-US-00002 Run 1 2 3 4 5 6 7 8* 9 10 11 (comp.) (comp.) (Inv.)
(Inv.) (comp.) (Inv.) (Inv.) (Inv.) (comp.) (Inv.) (Inv.)
[0105] It is noted that the .sup.13C{.sup.1H} NMR spectrum of
polypropylene obtained in run 5 (precatalyst 3b) did not show any
resonance at .delta. 44.88, 44.74, 44.08 and 31.74 ppm described in
Weng et al. (Macromolecules 2002, 35, 3838-3843) as characteristics
of long chain branched isotactic polypropylene. This is not the
case for the polypropylenes prepared according to the present
invention, with two catalyst systems, for which the
.sup.13C{.sup.1H} NMR spectra show clear resonances at .delta.
44.88, 44.74, 44.08 and 31.74 ppm.
[0106] According to the present of the present invention, long
chain branchings are obtained. It is, however, unexpected that a
second type of branchings, having specific .sup.13C NMR signals,
was also obtained. Table 2 reports the content of both first and
second type of branchings in the polypropylene obtained according
to the present invention.
TABLE-US-00003 TABLE 2 1.sup.st/2.sup.nd LCB.sup.a New LCB.sup.b
LCB.sub.total.sup.c Run precatalyst [/10,000 C] [/10,000 C]
[/10,000 C] 3 3c/3j 5.6 0.6 6.2 6 3c/3b nd 4.6 .gtoreq.4.6 7 3c/3b
0.9 5.4 6.3 8 3c/3b 0.9 6.9 7.8 10 3c/3f 0.9 4.3 5.2 nd = not
determined; .sup.acontent of long chain branching as disclosed by
Weng et al.; .sup.bcontent of second type of long chain branching
as disclosed in the present invention; .sup.ctotal long chain
branching per 10,000 C = (content of first type of long chain
branching as disclosed by Weng et al. + content of second type of
long chain branching as disclosed in the present invention) both
expressed/10,000 C.
[0107] The total content of long chain branchings of the
polypropylene obtained according to the process of the present
invention is higher than 5 per 10,000 C. This unexpected high long
chain branching content provides interesting viscoelastic
properties to the polypropylene obtained according to the present
invention. FIG. 1a-c represent the .sup.13C{.sup.1H} NMR spectrum
of the polypropylene obtained according to runs 3, 8 and 10
respectively, i.e. in presence of precatalysts 3c/3h, 3c/3b and
3c/3f respectively. The signals corresponding to the first type of
long chain branchings disclosed by Weng et al. are depicted by the
white triangles (.delta. 44.88, 44.74, 44.08 and 31.74 ppm) while
the new signals corresponding to the second type of long chain
branchings are depicted by the black diamonds (.delta. 51.1, 49.0,
38.9, 27.1, 26.6, 24.0, 23.3, 23.0, 22.9 and 19.8 ppm).
[0108] The rheological properties of the polypropylene according to
the present invention were also evaluated. FIG. 2 represents the
van Gurp-Palmen plot (.delta.=f(G*)), i.e. the representation of
the loss angle as a function of the complex modulus G*, of the
polypropylene according to the present invention and comparative
polypropylene. The curves were measured at T=190.degree. C., and at
shear rates ranging from 0.1 to 320 rads.sup.-1. In FIG. 2, the
thick solid line corresponds to a linear polypropylene (commercial
name: MR2001 commercialized by Total), the hatched line corresponds
to a high melt strength polypropylene (commercial name PF814
commercialized by Lyondel Basell), the dashed line corresponds to a
comparative polypropylene prepared in presence of precatalyst (3b)
and the dotted line corresponds to a long chain branched
polypropylene according to the present invention prepared in the
sequential presence of first and second precatalysts 3c and 3b. It
is noted that the van Gurp-Palmen rheological curve of
polypropylene according to the present invention shows a S-shaped
evolution of the loss angle 8 as a function of complex modulus G*,
with a first decrease at low values of G* followed by an increase
up to a maximum value of the loss angle at higher values of G*.
Such S-shaped curve is quite distinct from any of the other
continuously decreasing curves measured on the prior art
polypropylenes.
[0109] Hence, the polypropylene according to the present invention
has a new molecular architecture composed with two different types
of long chain branchings, leading to an improvement of its
elasticity properties compared to comparative polypropylene
obtained with precatalyst 3b only. The polypropylene according to
the present invention can be obtained by the process of the present
invention combining first and second precatalysts or first and
second active catalyst system as defined herein.
[0110] The terms and descriptions used herein are set forth by way
of illustration only and are not meant as limitations. Those
skilled in the art will recognize that many variations are possible
within the spirit and scope of the invention as defined in the
following claims, and their equivalents, in which all terms are to
be understood in their broadest possible sense unless otherwise
indicated. As a consequence, all modifications and alterations will
occur to others upon reading and understanding the previous
description of the invention. In particular, dimensions, materials,
and other parameters, given in the above description may vary
depending on the needs of the application.
* * * * *