U.S. patent application number 14/895807 was filed with the patent office on 2016-05-05 for ethylene-propylene copolymeric compositions with long methylene sequence lengths.
The applicant listed for this patent is EXXONMOBIL CHEMICAL PATENTS INC.. Invention is credited to Daniel L. Bilbao, Jo Ann M. Canich, Carlos U. DeGracia, Charles J. Ruff, Ian C. Stewart, Mun F. Tse.
Application Number | 20160122452 14/895807 |
Document ID | / |
Family ID | 55791461 |
Filed Date | 2016-05-05 |
United States Patent
Application |
20160122452 |
Kind Code |
A1 |
Tse; Mun F. ; et
al. |
May 5, 2016 |
Ethylene-Propylene Copolymeric Compositions With Long Methylene
Sequence Lengths
Abstract
This invention relates to methods to prepare and compositions
pertaining to branched ethylene-propylene copolymers that include
at least 50% ethylene content by weight as determined by FTIR; a
g'.sub.vis of less than 0.95; a M.sub.W of 150,000 to 250,000; a
methylene sequence length of 6 or greater as determined by .sup.13C
NMR, wherein the percentage of sequences of the length of 6 or
greater is more than 32%; and can have greater than 50% vinyl chain
end functionality.
Inventors: |
Tse; Mun F.; (Seabrook,
TX) ; Canich; Jo Ann M.; (Houston, TX) ; Ruff;
Charles J.; (Houston, TX) ; Bilbao; Daniel L.;
(Houston, TX) ; DeGracia; Carlos U.; (LaPorte,
TX) ; Stewart; Ian C.; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EXXONMOBIL CHEMICAL PATENTS INC. |
Baytown |
TX |
US |
|
|
Family ID: |
55791461 |
Appl. No.: |
14/895807 |
Filed: |
July 7, 2014 |
PCT Filed: |
July 7, 2014 |
PCT NO: |
PCT/US2014/045542 |
371 Date: |
December 3, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61847467 |
Jul 17, 2013 |
|
|
|
Current U.S.
Class: |
526/170 ;
526/195; 526/348 |
Current CPC
Class: |
C08F 4/65908 20130101;
C08F 210/16 20130101; C08F 210/16 20130101; C08F 4/65927 20130101;
C08F 210/02 20130101; C08F 210/06 20130101; C08F 2500/03 20130101;
C08F 4/65927 20130101; C08F 210/06 20130101; C08F 210/16
20130101 |
International
Class: |
C08F 210/02 20060101
C08F210/02 |
Claims
1. A branched ethylene-propylene copolymer comprising: at least 50%
ethylene content by weight as determined by FTIR; a g'.sub.vis of
less than 0.98; a methylene sequence length of 6 or greater as
determined by .sup.13C NMR, wherein the percentage of sequences of
the length of 6 or greater is more than 32%; and greater than 50%
vinyl chain end functionality is present.
2. The branched ethylene-propylene copolymer of claim 1, wherein
the g'.sub.vis is less than 0.95.
3. The branched ethylene-propylene copolymer of claim 1, wherein
the ethylene-propylene copolymer has a ratio of percentage of
saturated chain ends to percentage of vinyl chain that is greater
than 1.
4. The branched ethylene-propylene copolymer claim 1, wherein the
ethylene-propylene copolymer has a heat of fusion from 5 J/g to 50
J/g.
5. The branched ethylene-propylene copolymer of claim 1, wherein
the ethylene-propylene copolymer T.sub.m is from -10.degree. C. to
40.degree. C.
6. The branched ethylene-propylene copolymer of claim 1, wherein
the ethylene-propylene copolymer has a Mooney viscosity (ML) range
at 125.degree. C. of from 29 to 100 Mooney units (MU).
7. The branched ethylene-propylene copolymer of claim 1, wherein
the branched ethylene-propylene copolymer has a Mooney large
relaxation area (MLRA) of from 100 to 1000.
8. The branched ethylene-propylene copolymer of claim 1, wherein
the r.sub.1r.sub.2 is greater than 2.
9. The branched ethylene-propylene copolymer of claim 1, wherein
the branched ethylene-propylene copolymer has an elongation (break)
of at least 150%.
10. The branched ethylene-propylene copolymer of claim 1, wherein
the branched ethylene-propylene copolymer has a nomial stress range
of from 0.22 MPa to 0.32 MPa at a 50% strain and 0.15 MPa to 0.2
MPa at 150% strain, at a pull rate of 5.08 centimeters/minute.
11. The branched ethylene-propylene copolymer of claim 1, wherein
the branched ethylene-propylene copolymer ethylene content is from
50% to 55%.
12. A process for the preparation of the ethylene/propylene
branched polymer of claim 1, wherein the process comprises:
contacting ethylene and propylene, under polymerization conditions,
with at least a catalyst system comprising an activator and at
least one metallocene and obtaining a branched ethylene/propylene
copolymer having at least 50% ethylene content by weight as
determined by FTIR; a g'.sub.vis of less than 0.98; a methylene
sequence length of 6 or greater as determined by .sup.13C NMR,
wherein the percentage of sequences of the length of 6 or greater
is more than 32%; and greater than 50% vinyl chain end
functionality is present.
13. The process of claim 12, wherein the process is a solution
process.
14. The process of claim 12, wherein the metallocene compound is
represented by the formula: ##STR00002## where each R.sup.3 is
hydrogen; each R.sup.4 is independently a C.sub.1-C.sub.10 alkyl;
each R.sup.2, and R.sup.7 are independently hydrogen, or
C.sub.1-C.sub.10 alkyl; each R.sup.5 and R.sup.6 are independently
hydrogen, or C.sub.1-C.sub.50 substituted or unsubstituted
hydrocarbyl and R.sup.4 and R.sup.5, R.sup.5 and R.sup.6 and/or
R.sup.6 and R.sup.7 may optionally be bonded together to form a
ring structure; J is a bridging group represented by the formula
Ra.sub.2J, where J is C or Si, and each Ra is, independently
C.sub.1 to C.sub.20 substituted or unsubstituted hydrocarbyl, and
two R.sup.a form a cyclic structure incorporating J and the cyclic
structure may be a saturated or partially saturated cyclic or fused
ring system; and each X is is a univalent anionic ligand, or two Xs
are joined and bound to the metal atom to form a metallocycle ring,
or two Xs are joined to form a chelating ligand, a diene ligand, or
an alkylidene ligand.
15. The process of claim 12, wherein the metallocene compound is
one or more of:
cyclotetramethylenesilylenebis(2,4,7-trimethyl-indenyl)hafnium
dimethyl,
cyclotrimethylenesilylenebis(2,4,7-trimethyl-indenyl)hafnium
dimethyl,
cyclotetramethylenesilylenebis(2,4,7-trimethyl-indenyl)hafnium
dichloride,
cyclotrimethylenesilylenebis(2,4,7-trimethyl-indenyl)hafnium
dichloride, or mixtures thereof.
16. The process of claim 12, wherein the activator is
dimethylanilinium tetrakisperfluoronaphthylborate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is related to "Substituted
Metallocene Catalysts", U.S. Ser. No. 61/847,442 filed Jul. 17,
2013; and claims priority to U.S. Ser. No. 61/847,467 filed Jul.
17, 2013, which is herein incorporated by reference.
FIELD OF THE INVENTION
[0002] Branched ethylene-propylene copolymers with a high degree of
branching (g' of less than 1) and having 50 to 55 weight percent
ethylene content as measured by .sup.13C NMR are described. The
copolymers can be used as compatibilizers for polymer blends.
BACKGROUND OF THE INVENTION
[0003] Alpha-olefins, especially those containing 6 to 20 carbon
atoms, have been used as intermediates in the manufacture of
detergents or other types of commercial products. Such
alpha-olefins have also been used as monomers, especially in linear
low density polyethylene. Commercially produced alpha-olefins are
typically made by oligomerizing ethylene. Longer chain
alpha-olefins, such as vinyl-terminated polyethylenes are also
known and can be useful as building blocks following
functionalization or as macromonomers.
[0004] Some relevant publications includes U.S. Pat. No. 4,814,540;
JP 2005-336092 A2; US 2012-0245311 A1; Rulhoff et al. in 16
MACROMOLECULAR CHEMISTRY AND PHYSICS 1450-1460 (2006); Kaneyoshi et
al. in 38 MACROMOLECULES 5425-5435 (2005); Teuben et al. 62 J. MOL.
CATAL. 277-287 (1990); X. Yang et al., 31 ANGEW. CHEM. INTL ED.
ENGL. 1375-1377 (1992); Resconi et al. in 114 J. AM. CHEM. SOC.
1025-1032 (1992); Small and Brookhart 32 MACROMOLECULES 2120-2130
(1999); Weng et al., 21 MACROMOL RAPID COMM. 1103-1107 (2000); 33
MACROMOLECULES 8541-8548 (2000); Moscardi et al. in 20
ORGANOMETALLICS 1918-1931 (2001); Coates et al. in 38
MACROMOLECULES 6259-6268 (2005); Rose et al. 41 Macromolecules
559-567 (2008); Zhu et al., 35 Macromolecules 10062-10070(2002) and
24 MACROMOLECULES RAP. COMMUN. 311-315 (2003); Janiak and Blank in
236 MACROMOL. SYMP. 14-22 (2006). Other references include U.S Ser.
No. 13/072,280 filed Mar. 25, 2011, published on 9/27/2012 and USSN
61/467681 filed 3/25/11, published on Sep. 27, 2012 also relate to
olefin polymerization, particularly to produce vinyl terminated
polymers.
[0005] However, few catalysts/processes have been shown to produce
branched chain unsaturations in high yields, a wide range of
molecular weight, and with high catalyst activity for
propylene-based polymerizations. The physical properties of
branched oligomer and polymers have attracted considerable
attention. Branching in an oligomer or a polymer can result in
solution and solid-state properties markedly different than those
of its linear counterpart. Accordingly, there is need for new
catalysts and/or processes that produce branched polymers in high
yields, with a wide range of molecular weight, and with high
catalyst activity.
SUMMARY OF THE INVENTION
[0006] Branched amorphous ethylene-propylene oligomers and
polymers, and compositions comprising such branched amorphous
ethylene-propylene oligomers and polymers are described. The
branched ethylene-propylene copolymers include one or more of the
following: at least 50% ethylene content by weight as determined by
FTIR; a g'.sub.vis of less than 0.98; a M.sub.W of 150,000 to
250,000; a methylene sequence length of 6 or greater as determined
by .sup.13C NMR, wherein the percentage of sequences of the length
of 6 or greater is more than 32%; and greater than 50% vinyl chain
end functionality. Processes, preferably homogenous processes, for
making the branched ethylene-propylene oligomers and polymers are
described, wherein the processes comprise contacting ethylene and
propylene with a catalyst system, comprising an activator and at
least one metallocene.
BRIEF DESCRIPTION OF THE FIGURES
[0007] FIG. 1 provides mEPCs made by catalyst 1/activator 1 have
much higher melting points than mEPCs made by catalyst 2/activator
2.
[0008] FIG. 2 demonstrates that mEPCs made by catalyst 1/activator
1 have higher heats of fusion than mEPCs made by catalyst
2/activator 2.
[0009] FIG. 3(a-c) is a GPC-3D curve for sample 1 prepared with
catalyst 2/activator 2. Run conditions and instrument and polymer
parameters: Inject Mass (mg) =0.2784; Calc. Mass (mg) =0.256
(91.9%); Adjusted Flow Rate (ml/m) =0.543; Column Cal. CO =12.474;
Column Cal. C1=-0.31335; Column Cal. C2=-0.0025044; Column Cal.
C3=0; Inject Mark (ml)=31.837; Vistalon B1=0.953; Random Coil
Analysis (5); A2 (Input Value)=0.00106; (dn/dc)=0.104; LS to DRI
(ml)=0.152; LS to Vis. (ml) =0.385; K (sample)=0.00042613; alpha
(sample)=0.699; LS Calib. Const.=1.5348e-05; DRI Const.=3.364e-05;
DP Const.=0.8722; IP Baseline=27.3 KPa.
[0010] FIG. 4 (a-c) is a GPC-3D curve for sample 2 prepared with
catalyst 1/ activator 1. Run conditions and instrument and polymer
parameters: Inject Mass (mg)=0.46; Calc. Mass (mg)=0.415 (90.2%);
Adjusted Flow Rate (ml/m)=0.543; Column Cal. C0=12.474; Column
C1=-0.31335; Column Cal. C2=-0.0025044; Column Cal. C3=0; Inject
Mark (ml)=31.837; Vistalon B1=0.846; Random Coil Analysis (5); A2
(Input Value=0.001033; (dn/dc)=0.104; LS to DRI (ml)=0.152; LS to
Vis. (ml)=0.385; K (sample) =0.00041796; alpha (sample) =0.699; LS
Calib. Const. =1.5348e-05; DRI Const.=3.364e-05; DP Const. =0.8722;
IP Baseline =27.3 KPa.
[0011] FIG. 5 (a-c) is a GPC-3D curve for sample 3 prepared with
catalyst 1/activator 1. Run conditions and instrument and polymer
parameters: Inject Mass (mg)=0.267; Calc. Mass (mg)=0.286 (107%);
Adjusted Flow Rate (ml/m)=0.543; Column Cal. C0=12.474; Column Cal.
C1=-0.31335; Column Cal. C2=-0.0025044; Column Cal. C3=0; Inject
Mark (ml)=31.837; Vistalon B1=0.916; Random Coil Analysis (5); A2
(Input Value)=0.001048; (dn/dc)=0.104; LS to DRI (ml)=0.152; LS to
Vis. (ml)=0.392; K (sample)=0.00042251; alpha (sample)=0.699; LS
Calib. Const.=1.5333e-05; DRI Const.=3.605e-05; DP Const.=0.9328;
IP Baseline =28.3 KPa.
[0012] FIG. 6 are representative stress-strain curves of mEPCs
measured at room temperature and a pull rate of 5.08 cm/min
[0013] FIG. 7a provides Van Gurp-Palmen plots of mEPCs prepared
with catalyst 1/activator 1.
[0014] FIG. 7b provides Van Gurp-Palmen plots of mEPCs prepared
with catalyst 2/activator 2.
[0015] FIG. 8a provides the complex viscosity versus frequency of
mEPCs prepared with catalyst 1/activator 1.
[0016] FIG. 8b provides the complex viscosity versus frequency of
mEPCs prepared with catalyst 2/activator 2.
DETAILED DESCRIPTION
[0017] Described herein are branched ethylene-propylene oligomers
and polymers and processes to produce the branched
ethylene-propylene oligomers and polymers and compositions.
"Branched" as used herein means a polyolefin having a g'.sub.vis of
0.98 or less.
[0018] These branched polyolefins having high amounts of allyl
chain ends may find utility as macromonomers for the synthesis of
polyolefins, such as linear low density polyethylene, block
copolymers, and as additives, for example, as additives to, or
blending agents in, lubricants, waxes, and adhesives.
Advantageously, when used as an additive, such as to film
compositions, the branched nature of these polyolefins may improve
rheological properties in molten state and desired mechanical
properties by allowing optimal thermoforming and molding at lower
temperatures, thereby reducing energy consumption of the film
forming process, as compared to linear polyolefin analogues.
Additionally, the high amounts of allyl chain ends of these
branched polyolefins provides a facile path to functionalization.
The functionalized branched polyolefins may be also useful as
additives or blending agents.
[0019] The branched ethylene-propylene copolymers include one or
more of the following: at least 50% ethylene content by weight as
determined by FTIR; a g'.sub.vis of less than 0.98; a M.sub.w of
150,000 to 250,000; a methylene sequence length of 6 or greater as
determined by .sup.13C NMR, wherein the percentage of sequences of
the length of 6 or greater is more than 32%; and greater than 50%
vinyl chain end functionality.
[0020] The ethylene-propylene copolymer comprise ethylene derived
units, as determined by FTIR, within the range of from 30 or 40 or
50 wt % to at least 55 or 60 or 65 wt % by weight of the copolymer,
or alternatively the weight percent of ethylene in the
ethylene-propylene copolymer is at least 50 wt %, more particularly
from 50 wt % to 55 wt %, the remainder being propylene-derived
units.
[0021] An "olefin," alternatively referred to as "alkene," is a
linear, branched, or cyclic compound of carbon and hydrogen having
at least one double bond. For purposes of this specification and
the claims appended thereto, when a polymer or copolymer is
referred to as comprising an olefin, including, but not limited to
ethylene and propylene, the olefin present in such polymer or
copolymer is the polymerized form of the olefin. For example, when
a copolymer is said to have an "ethylene" content of 50 wt % to 55
wt %, it is understood that the mer unit in the copolymer is
derived from ethylene in the polymerization reaction and said
derived units are present at 50 wt % to 55 wt %, based upon the
weight of the copolymer. A "polymer" has two or more of the same or
different mer units. A "homopolymer" is a polymer having mer units
that are the same. A "copolymer" is a polymer having two or more
mer units that are different from each other. A "terpolymer" is a
polymer having three mer units that are different from each other.
"Different" as used to refer to mer units indicates that the mer
units differ from each other by at least one atom or are different
isomerically. Accordingly, the definition of copolymer, as used
herein, includes terpolymers and the like. An oligomer is typically
a polymer having a low molecular weight (such an Mn of less than
25,000 g/mol, preferably less than 2,500 g/mol) or a low number of
mer units (such as 75 mer units or less).
[0022] As used herein the term "branched oligomer or branched
polymer" is defined as the polymer molecular architecture obtained
when an oligomer (or a polymer) chain (also referred to as
macromonomer) with reactive polymerizable chain ends is
incorporated into another oligomer/polymer chain during the
polymerization of the latter to form a structure comprising a
backbone defined by one of the oligomer chains with branches of the
other oligomer chains extending from the backbone. A linear
oligomer differs structurally from the branched oligomer because of
lack of the extended side arms. For some catalyst systems, the
oligomer with a reactive polymerizable chain end can be generated
in-situ and incorporated into another growing chain to form a
homogeneous branched oligomers in a single reactor. A linear
polymer has a branching index (g'.sub.vis) of 0.98 or more,
preferably 0.99 or more, preferably 1.0 (1.0 being the theoretical
limit of g'.sub.vis).
[0023] The inventive ethylene-propylene polymers disclosed herein
are branched, having a branching index (g'.sub.vis) of less than
0.98 (preferably 0.95 or less, preferably 0.90 or less, even more
preferably 0.85 or less).
[0024] The inventive copolymers also have a methylene sequence
length of 6 or greater as determined by .sup.13C NMR, wherein the
percentage of sequences of the length of 6 or greater is more than
32%.
[0025] Preferably, the heat of fusion of the ethylene-propylene
copolymer has a heat of fusion (AH.sub.f) of from 5 or 10 or 12 or
16 J/g to 30 or 40 or 50 J/g. The inventive ethylene-propylene
copolymer also have at least 50% allyl chain ends, relative to
total unsaturated chain ends (preferably 60% or more, preferably
70% or more, preferably 75% or more, preferably 80% or more,
preferably 90% or more, preferably 95% or more).
[0026] The ethylene-propylene copolymers described herein can also
have one or more of the following characteristics.
[0027] In one embodiment, the branched ethylene-propylene
copolymers described herein have a Mw/Mn range of from 2.2 to 2.6.
Preferably, the Mw/Mn is less than 2.4. Both Mn and Mw are
determined using GPC-DRI.
[0028] In one aspect, the branched ethylene-propylene copolymers
described herein have a Mooney viscosity (ML) ML (1+4) at
125.degree. C. of from 29 to 100 MU (preferably from 40 to 82;
preferably from 50 to 68), where MU is Mooney Units.
[0029] In another aspect, the branched ethylene-propylene
copolymers described herein have a Mooney large relaxation area
(MLRA) of from 100 to 1000 (preferably from 175 to 610; preferably
from 275 to 545; preferably from 325 to 530).
[0030] In still another aspect, the branched ethylene-propylene
copolymers described herein have a melting point (Tm) within the
range of from -30 or -20 or -10.degree. C. to 10 or 20 or 30 or
40.degree. C.
[0031] In yet another aspect, the branched ethylene-polymer
copolymers described herein have an elongation (break) of 150% or
greater and/or a nomial stress range of from 0.22 MPa to 0.32 MPa
at 50% strain and/or 0.15 MPa to 0.2 MPa at 150% strain, at a pull
rate of 5.08 centimeters/minute.
[0032] In an embodiment, the branched ethylene-propylene copolymers
described herein have a phase angle of 50.degree. at 8000 G*Pa and
25.degree. at 500,000 G*Pa at 190.degree. C.
[0033] In another embodiment, the branched ethylene-propylene
copolymers herein have a phase angle of 45.degree. at 10,000 G*Pa
and a range of 25.degree. to 35.degree. at 100,000 G*Pa at
190.degree. C.
[0034] In still another embodiment, the branched ethylene-propylene
copolymers herein have an average sequence length for methylene
sequences two and longer of from 8 to 9.
[0035] In still yet another embodiment, the branched
ethylene-propylene copolymers herein have an average sequence
length for methylene sequences six and longer of from 12 to 14.
[0036] In yet another aspect, the branched ethylene-propylene
copolymers have an r.sub.1r.sub.2 of from 2.7 to 2.8.
[0037] In some embodiments, the branched polymers have 50% or
greater allyl chain ends (preferably 60% or more, preferably 70% or
more, preferably 80% or more, preferably 90% or more, preferably
95% or more). Branched polymers generally have a chain end (or
terminus) which is saturated and/or an unsaturated chain end. The
unsaturated chain end of the inventive polymers comprises "allyl
chain ends." An allyl chain end is represented by the formula:
##STR00001##
where "P" represents the rest of polymer chain. "Allylic vinyl
group," "allyl chain end," "vinyl chain end," "vinyl termination,"
"allylic vinyl group" and "vinyl terminated" are used
interchangeably in the following description.
[0038] The unsaturated chain ends may be further characterized by
using bromine electrometric titration, as described in ASTM D 1159.
The bromine number obtained is useful as a measure of the
unsaturation present in the sample. In embodiments herein, branched
polyolefins have a bromine number which, upon complete
hydrogenation, decreases by at least 50% (preferably by at least
75%).
[0039] The inventions described herein relate to branched
ethylene-propylene polymers and polymerization processes to produce
them, wherein the formation of polymers with an allyl chain end and
reinsertion of oligomers with allyl chain ends into another
oligomer take place in the same polymerization zone or in the same
reactor. Preferably a single catalyst system is used, more
preferably two different metallocene catalysts are used in
combination, and most preferably, two different metallocene
catalysts wherein one is a symmetrical metallocene (meaning that
both cyclopentadienyl groups are the same) and the other
unsymmetrical (meaning that each of the two cyclopentadienyl groups
are different). The catalyst system is capable of producing an
oligomer with allyl chain end and reinserting the oligomer into
another oligomer to form a branched polymer.
[0040] Processes, preferably homogenous processes, for making the
branched ethylene-propylene oligomers and polymers are described,
wherein the processes comprise contacting ethylene and propylene
with a catalyst system, comprising an activator and at least one
metallocene.
[0041] Suitable indenyl metallocene catalysts, activators and
catalyst systems useful herein are those described herein below as
well as those described in attorney docket number 2013EM185 filed
concurrently herewith.
[0042] Suitable catalysts include, for example,
rac-tetramethylenesilylene-bis(2,4,7-trimethylindenyl)hafnium (IV)
dimethyl. Suitable activators include, for example,
dimethylanilinium tetrakisperfluoronaphthylborate.
[0043] Conversion is the amount of monomer and comonomers that are
converted to polymer products, and is reported as weight percent
and is calculated based on the polymer yield and the amount of
monomer fed into the reactor.
[0044] Catalyst activity (also referred to as catalyst
productivity) is a measure of amount of polymer product produced by
unit weight of the catalyst in a given time period. For a
continuous process, the catalyst activity is reported as the
kilogram of polymer product (P) produced per kilogram of catalyst
(cat) used (kgP/kgcat). In a batch process, catalyst activity is
reported as the grams of polymer product produced per gram of
catalyst and per hour (g P/g cat Hr).
[0045] The processes described herein can be run at temperatures
and pressures suitable for commercial production of the branched
ethylene-propylene polymers. Typical temperatures and/or pressures
include a temperature greater than 35.degree. C. (preferably in the
range of from 35 to 150.degree. C., from 40 to 140.degree. C., from
60 to 140.degree. C., or from 80 to 130.degree. C.) and a pressure
in the range of from 0.1 to 10 MPa (preferably from 0.5 to 6 MPa or
from 1 to 4 MPa).
[0046] The processes described herein have a residence time
suitable for commercial production of the branched
ethylene-propylene polymers. In a typical polymerization, the
residence time of the polymerization process is up to 300 minutes,
preferably in the range of from 5 to 300 minutes, preferably from
10 to 250 minutes, preferably from 10 to 120 minutes, or preferably
from 10 to 60 minutes. At a given feed condition, long residence
time may increase the monomer conversion, thereby increasing the
oligomer concentration and decreasing the monomer concentration in
a reactor. This will enhance the level of branching of the
oligomer. In one embodiment, the residence time is used to control
the branching level and to optimize the branching structures for
specific end-uses.
[0047] The polymer product can be recovered from solution at the
completion of the polymerization by any of the techniques well
known in the art such as steam stripping followed by extrusion
drying or by devolatilizing extrusion. Separated solvent/diluent
and monomers can be recycled back in the reactor.
[0048] In a most preferred embodiment, two different
metallocene/activator systems,
rac-tetramethylenesilylene-bis(2,4,7-trimethylindenyl)hafnium (IV)
dimethyl (catalyst 1)/dimethylanilinium
tetrakisperfluoronaphthylborate (activator 1) and
bis(para-triethylsilylphenyl)methylene(2,7-di-tert-butyl-fluoren-9-yl)(cy-
clopentadienyl)hafnium(IV) dimethyl (catalyst 2)/dimethylanilinium
tetrakisperfluorophenylborate (activator 2), were used to prepare
ethylene-propylene copolymers. At similar nominal ethylene content,
two different types of copolymer sequence distributions were
obtained. At an ethylene content of 55 wt %, the mEPC prepared with
catalyst 1/activator 1 has, on average, longer methylene sequences
based on .sup.13C NMR studies, leading to a melting point (T.sub.m)
of 30.degree. C. higher than the mEPC prepared with catalyst
2/activator 2. The former copolymer also has better tensile
properties, a higher melt strength and a higher degree of shear
thinning due to the presence of branching, as demonstrated by
Mooney viscosity, GPC-3D, and .sup.1H NMR.
EXAMPLES
[0049] In conducting the .sup.13C NMR investigations, samples were
dissolved in tetrachloroethane-d2 at concentrations between 10 to
15 wt % in a 10 mm NMR tube. .sup.13C NMR data was collected at
120.degree. C. using a Varian spectrometer with a .sup.1H frequency
of at least 400 MHz. A 90 degree pulse, an acquisition time
adjusted to give a digital resolution between 0.1 and 0.12 Hz, at
least a 10 second pulse acquisition delay time with continuous
broadband proton decoupling using swept square wave modulation
without gating was employed during the entire acquisition period.
The spectra were acquired using time averaging to provide a signal
to noise level adequate to measure the signals of interest.
[0050] Prior to data analysis, spectra were referenced by setting
the chemical shift of the (--CH.sub.2--).sub.n (where n>6)
signal to 29.9 ppm.
[0051] Chain ends for quantization were identified using the
signals shown in the table below. N-butyl and n-propyl were not
reported due to their low abundance (less than 5%) relative to the
chain ends shown in the table below.
TABLE-US-00001 Chain end .sup.13CNMR Chemical shift P~i-Bu 23.5 to
25.5 and 25.8 to 26.3 ppm E~i-Bu 39.5 to 40.2 P~Vinyl 41.5 to 43
E~Vinyl 33.9 to 34.4
[0052] The number of vinyl chain ends, vinylidene chain ends and
vinylene chain ends is determined using .sup.1H NMR using
deuterated tetrachloroethane as the solvent on an at least 250 MHz
NMR spectrometer, and in selected cases, confirmed by .sup.13C NMR.
Proton NMR data was collected at either room temperature or
120.degree. C. (for purposes of the claims, 120.degree. C. shall be
used) in a 5 mm probe using a Varian spectrometer with a .sup.1H
frequency of at least 400 MHz. Data was recorded using a maximum
pulse width of 45.degree. C., 8 seconds between pulses and signal
averaging 120 transients. Spectral signals were integrated and the
number of unsaturation types per 1000 carbons was calculated by
multiplying the different groups by 1000 and dividing the result by
the total number of carbons. The number averaged molecular weight
(Mn) was calculated by dividing the total number of unsaturated
species into 14,000, assuming one unsaturation per polyolefin
chain.
[0053] The chain end unsaturations are measured as follows. The
vinyl resonances of interest are between from 5.0 to 5.1 ppm (VRA),
the vinylidene resonances between from 4.65 to 4.85 ppm (VDRA), the
vinylene resonances from 5.31 to 5.55 ppm (VYRA), the
trisubstituted unsaturated species from 5.11 to 5.30 ppm (TSRA) and
the aliphatic region of interest between from 0 to 2.1 ppm (IA).
The number of vinyl groups/1000 Carbons is determined from the
formula:
(VRA*500)/(((IA+VRA+VYRA+VDRA)/2)+TSRA).
Likewise, the number of vinylidene groups/1000 Carbons is
determined from the formula:
(VDRA*500)/(((IA+VRA+VYRA+VDRA)/2)+TSRA),
the number of vinylene groups/1000 Carbons from the formula
(VYRA*500)/(((IA +VRA+VYRA+VDRA)/2)+TSRA)
and the number of trisubstituted groups from the formula
(TSRA*1000)/(((IA+VRA+VYRA+VDRA)/2)+TSRA).
VRA, VDRA, VYRA, TSRA and IA are the integrated normalized signal
intensities in the chemical shift regions defined above.
[0054] Molecular weights (number average molecular weight (Mn),
weight average molecular weight (Mw), and z-average molecular
weight (Mz)) were determined using a Polymer Laboratories Model 220
high temperature SEC equipped with on-line differential refractive
index (DRI), light scattering (LS), and viscometer (VIS) detectors.
It used three Polymer Laboratories PLgel 10 m Mixed-B columns for
separation using a flow rate of 0.54 ml/min and a nominal injection
volume of 300 .mu.L. The detectors and columns were contained in an
oven maintained at 135.degree. C. The stream emerging from the SEC
columns was directed into a miniDAWN optical flow cell and then
into the DRI detector. The DRI detector was an integral part of the
Polymer Laboratories SEC. The viscometer was inside the SEC oven,
positioned after the DRI detector. The details of these detectors
as well as their calibrations have been described by, for example,
T. Sun, P. Brant, R. R. Chance, and W. W. Graessley, in
Macromolecules, Volume 34, Number 19, 6812-6820, (2001),
incorporated herein by reference.
[0055] Solvent for the SEC experiment was prepared by dissolving 6
grams of butylated hydroxy toluene as an antioxidant in 4 liters of
Aldrich reagent grade 1, 2, 4-trichlorobenzene (TCB). The TCB
mixture was then filtered through a 0.7 .mu.m glass pre-filter and
subsequently through a 0.1 .mu.m Teflon filter. The TCB was then
degassed with an online degasser before entering the SEC. Polymer
solutions were prepared by placing dry polymer in a glass
container, adding the desired amount of TCB, then heating the
mixture at 160.degree. C. with continuous agitation for 2 hours.
All quantities were measured gravimetrically. The TCB densities
used to express the polymer concentration in mass/volume units were
1.463 g/mL at room temperature and 1.324 g/mL at 135.degree. C. The
injection concentration was from 1.0 to 2.0 mg/mL, with lower
concentrations being used for higher molecular weight samples.
Prior to running each sample the DRI detector and the injector were
purged. Flow rate in the apparatus was then increased to 0.5
mL/minute, and the DRI was allowed to stabilize for 8 to 9 hours
before injecting the first sample. The concentration, c, at each
point in the chromatogram was calculated from the
baseline-subtracted DRI signal, I.sub.DRI, using the following
equation:
K.sub.DRII.sub.DRI/(dn/dc)
where K.sub.DRI is a constant determined by calibrating the DRI,
and (dn/dc) is the refractive index increment for the system. The
refractive index, n=1.500 for TCB at 135.degree. C. and .lamda.=690
nm. For purposes herein and the claims thereto (dn/dc)=0.104 for
propylene polymers and 0.1 otherwise. Units of parameters used
throughout this description of the SEC method are: concentration is
expressed in g/cm.sup.3, molecular weight is expressed in g/mol,
and intrinsic viscosity is expressed in dL/g.
[0056] The light scattering detector was a high temperature mini
DAWN (Wyatt Technology, Inc.). The primary components are an
optical flow cell, a 30 mW, 690 nm laser diode light source, and an
array of three photodiodes placed at collection angles of
45.degree., 90.degree., and 135.degree.. The molecular weight, M,
at each point in the chromatogram was determined by analyzing the
LS output using the Zimm model for static light scattering (M. B.
Huglin, LIGHT SCATTERING FROM POLYMER SOLUTIONS, Academic Press,
1971):
K o c .DELTA. R ( .theta. ) = 1 MP ( .theta. ) + 2 A 2 c
##EQU00001##
[0057] Here, .DELTA.R(.theta.) is the measured excess Rayleigh
scattering intensity at scattering angle 0, c is the polymer
concentration determined from the DRI analysis, A.sub.2 is the
second virial coefficient (for purposes herein, A.sub.2=0.0006 for
propylene polymers, 0.0015 for butene polymers and 0.001
otherwise), (dn/dc)=0.104 for propylene polymers, 0.098 for butene
polymers and 0.1 otherwise, P(.theta.) is the form factor for a
monodisperse random coil, and K.sub.o is the optical constant for
the system:
K o = 4 .pi. 2 n 2 ( dn / dc ) 2 .lamda. 4 N A ##EQU00002##
where N.sub.A is Avogadro's number, and (dn/dc) is the refractive
index increment for the system. The refractive index, n =1.500 for
TCB at 145.degree. C. and =690 nm.
[0058] A high temperature viscometer from Viscotek Corporation was
used to determine specific viscosity. The viscometer has four
capillaries arranged in a Wheatstone bridge configuration with two
pressure transducers. One transducer measures the total pressure
drop across the detector, and the other, positioned between the two
sides of the bridge, measures a differential pressure. The specific
viscosity, .eta..sub.s, for the solution flowing through the
viscometer was calculated from their outputs. The intrinsic
viscosity, [.eta.], at each point in the chromatogram was
calculated from the following equation:
.eta..sub.s=c[.eta.]+0.3(c[.eta.]).sup.2
where c is concentration and was determined from the DRI
output.
[0059] The branching index (g'.sub.vis) is defined as the ratio of
the intrinsic viscosity of the branched polymer to the intrinsic
viscosity of a linear polymer of equal molecular weight and same
composition, and was calculated using the output of the
SEC-DRI-LS-VIS method as follows. The average intrinsic viscosity,
[.eta.].sub.avg, of the sample was calculated by:
[ .eta. ] avg = c i [ .eta. ] i c i ##EQU00003##
where the summations are over the chromatographic slices, i,
between the integration limits
[0060] The branching index g'.sub.vis is defined as:
g vis ' = [ .eta. ] avg kM v .alpha. ##EQU00004##
[0061] The intrinsic viscosity of the linear polymer of equal
molecular weight and same composition was calculated using the
Mark-Houwink equation. For purpose of the embodiments described
herein and claims thereto, k=0.000579 and .alpha.=0.695 for
ethylene polymers, k=0.0002288 and .alpha.=0.705 for propylene
polymers, and k=0.00018 and .alpha.=0.7 for butene polymers. For
EP, the values of k and a are determined based on the
ethylene/propylene composition using a standard calibration
procedure such that: k=(1-0.0048601EP
-6.8989.times.10.sup.-6EP.sup.2).times.5.79.times.10.sup.-4(200,000).sup.-
--Trunc.sup.(0.1EP).sup./1000 and .alpha.=0.695+Trunc(0.1EP)/1000,
where EP is the weight percent of propylene in the EP, and Trunc
indicates that only the integer portion is kept in the calculation.
For example, Trunc(5.3)=5. M.sub.v is the viscosity-average
molecular weight based on molecular weights determined by LS
analysis. See Macromolecules, 2001, 34, pp. 6812-6820 and
Macromolecules, 2005, 38, pp. 7181-7183, for guidance on selecting
a linear standard having similar molecular weight and comonomer
content, and determining k coefficients and a exponents. The
molecular weight data reported here are those determined using GPC
DRI detector, unless otherwise noted.
[0062] Viscosity was measured using a Brookfield Viscometer
according to ASTM D-3236.
[0063] Peak melting point, Tm, (also referred to as melting point),
peak crystallization temperature, Tc, (also referred to as
crystallization temperature), glass transition temperature (Tg),
heat of fusion (.DELTA.H.sub.f), and percent crystallinity were
determined using the following DSC procedure according to ASTM
D3418-03. Differential scanning calorimetric (DSC) data were
obtained using a TA Instruments model Q200 machine. Samples
weighing approximately 5-10 mg were sealed in an aluminum hermetic
sample pan. The DSC data were recorded by first gradually heating
the sample to 200.degree. C. at a rate of 10.degree. C./minute. The
sample was kept at 200.degree. C. for 2 minutes, then cooled to
-90.degree. C. at a rate of 10.degree. C./minute, followed by an
isothermal for 2 minutes and heating to 200.degree. C. at
10.degree. C./minute. Both the first and second cycle thermal
events were recorded. Areas under the endothermic peaks were
measured and used to determine the heat of fusion and the percent
of crystallinity. The percent crystallinity is calculated using the
formula, [area under the melting peak (Joules/gram)/B
(Joules/gram)] *100, where B is the heat of fusion for the 100%
crystalline homopolymer of the major monomer component. These
values for B are to be obtained from the Polymer Handbook, Fourth
Edition, published by John Wiley and Sons, New York 1999, provided
however that a value of 189 J/g (B) is used as the heat of fusion
for 100% crystalline polypropylene, a value of 290 J/g is used for
the heat of fusion for 100% crystalline polyethylene. The melting
and crystallization temperatures reported here were obtained during
the second heating/cooling cycle unless otherwise noted.
[0064] All of the examples were produced in a 1-liter,
solution-phase continuous stirred tank reactor. The reactor
temperature was controlled by metering a mixture of chilled water
and steam to the reactor jacket, and reactor pressure was
maintained by adjusting the set pressure on a back-pressure
regulator downstream of the reactor. Raw materials (ethylene,
propylene, isohexane, and toluene) were obtained from an integrated
pipeline source.
[0065] Isohexane and toluene were further purified by passing the
material through a series of adsorbent columns containing either 3A
mole sieves (isohexane) or 13X mole sieves (toluene) followed by
treatment with alumina. Ethylene and propylene monomers were
purified on-line by passing the feed streams through beds of 3A
mole sieves, and metered to a mixing manifold using mass flow
controllers (Brooks), where they were combined with the isohexane
solvent prior to entering the reactor. Separate feeds of scavenger
(tri-n-octyl aluminum in isohexane) and catalyst (premixed with
activator in toluene), were also supplied to the reactor. Nominal
reactor residence times were on the order of 10 minutes, after
which the continuous reactor effluent was collected and first
air-dried in a hood to evaporate most of the solvent and unreacted
monomers, and then dried in a vacuum oven at a temperature of
80.degree. C. for 12 hours. The vacuum oven dried samples were then
weighed to obtain the final polymer yield which could then be used
to calculate catalyst activity (also referred as to catalyst
productivity) based on the ratio of yield to catalyst feed
rate.
[0066] Two different metallocene/activator systems, catalyst
1/activator 1 and catalyst 2/activator 2, were used to prepare
ethylene/propylene copolymers (metallocene derived
ethylene/propylene copolymers, "mEPCs") with various ethylene
contents in a semi-continuous lab reactor. The process conditions
and the characterization of some mEPCs prepared with catalyst
1/activator 1 are shown in Table 1.
[0067] The polymer C.sub.2 wt % was measured by FTIR, ASTM
D3900.
[0068] LS and DRI denote the methods of light scattering and
differential refractive index used in the GPC-3D experiment,
respectively.
[0069] ML is the Mooney viscosity and MLRA is the Mooney large
relaxation area for 100 s, both measured at 125.degree. C.
[0070] Processability is arguably one of the most important and
critical properties of rubber and rubber compounds. Mooney
viscosity is a property used to monitor the quality of both natural
and synthetic rubbers. It measures the resistance of rubber to flow
at a relatively low shear rate. The highly branched compositions
herein have a Mooney viscosity ML (1+4) at 125.degree. C. of 30 to
100 MU (preferably 40 to 100; more preferably 50 to 100; even more
preferably 60 to 100), where MU is Mooney Units.
[0071] While the Mooney viscosity indicates the plasticity of the
rubber, the Mooney relaxation area (MLRA) provides a certain
indication of the effects of molecular weight distribution and
elasticity of the rubber. The highly branched compositions also
have a MLRA of 100 to 1000 (preferably 200 to 1000; more preferably
300 to 1000; even more preferably 450 to 950).
[0072] Another indication of melt elasticity is the ratio of
MLRA/ML. This ratio has the dimension of time and can be considered
as a "relaxation time." A higher number signifies a higher degree
of melt elasticity. Long chain branching will slow down the
relaxation of the polymer chain, hence increasing the value of
MLRA/ML. The highly branched compositions of this invention
preferably have an MLRA/ML ratio greater than 5, preferably greater
than 6, preferably greater than 7 and most preferably greater than
8, preferably for mEPCs with a Mw/Mn from 2 to 3 or 4, higher than
the precursor mEPDM rubber, or desirably, the MLRA/ML ratio is
within a range of from 5 or 6 to 10 or 12 or 14.
[0073] Mooney viscosity and Mooney relaxation area are measured
using a Mooney viscometer, operated at an average shear rate of 2
s.sup.-1, according to the following modified ASTM D1646.
[0074] ASTM D1646 was modified as follows: A square of sample is
placed on either side of the rotor. The cavity is filled by
pneumatically lowering the upper platen. The upper and lower
platens are electrically heated and controlled at 125.degree. C.
The torque to turn the rotor at 2 rpm is measured by a torque
transducer. The sample is preheated for 1 minute after the platens
were closed. The motor is then started and the torque is recorded
for a period of 4 minutes. Results are reported as ML (1+4) at
125.degree. C., where M is Mooney viscosity number, L denotes the
large rotor, 1 is the sample preheat time in minutes, 4 is the
sample run time in minutes after the motor starts, and 125.degree.
C. is the test temperature.
[0075] The MLRA data is obtained from the Mooney viscosity
measurement when the rubber relaxed after the rotor is stopped. The
MLRA is the integrated area under the Mooney torque-relaxation time
curve from 1 to 100 seconds. The MLRA can be regarded as a stored
energy term which suggests that, after the removal of an applied
strain, the longer or branched polymer chains can store more energy
and require longer time to relax. Therefore, the MLRA value of a
bimodal rubber (the presence of a discrete polymeric fraction with
very high molecular weight and distinct composition) or a long
chain branched rubber are larger than a broad or a narrow molecular
weight rubber when compared at the same Mooney viscosity
values.
[0076] There are essentially no gels in the present mEPCs based on
the fact that the values of GPC-3D mass recovery are all greater
than or equal to 90%. Using the DSC second melt experiments, the
values of the melting point (T.sub.m) and the heat of fusion
(H.sub.f) of a larger group of these copolymers were determined,
FIGS. 1-2. The melting temperature, T.sub.m, of the polymers were
measured using a DSC Q100 equipped with 50 auto-samplers from TA
Instruments. This DSC was calibrated with an indium standard
weekly. Typically, 6-10 mg of a polymer was sealed in an aluminum
pan with a hermetic lid and loaded into the instrument. In a
nitrogen environment, the sample was first cooled to -90.degree. C.
at 20.degree. C./min The sample was heated to 220.degree. C. at
10.degree. C./min and melting data (first heat) were acquired. This
provides information on the melting behavior under "as-received"
conditions, which can be influenced by thermal history as well as
sample preparation method. The sample was then equilibrated at
220.degree. C. to erase its thermal history.
[0077] Crystallization data (first cool) were acquired by cooling
the sample from the melt to -90.degree. C. at 10.degree. C./min and
equilibrated at -90.degree. C. Finally, the sample was heated again
to 220.degree. C. at 10.degree. C./min to acquire additional
melting data (second heat). The endothermic melting transition
(second heat) was analyzed for peak temperature as Tm and for area
under the peak as heat of fusion (Hf).
[0078] The mEPCs made by catalyst 1/activator 1 have higher values
of T.sub.m and H.sub.f than the mEPCs made by catalyst 2/activator
2. At an ethylene content of 55 wt %, the mEPC prepared with
catalyst 1/activator 1 has a longer methylene sequence than that
prepared with catalyst 2/activator 2 based on .sup.13C NMR studies,
Table 2. This leads to a T.sub.m of 30.degree. C. higher for the
mEPC prepared with catalyst 1/activator 1 compared to samples from
the catalyst 2/activator 2 catalyst system. In Table 2, the values
of wt % C.sub.2 of mEPC determined by .sup.13C NMR and FTIR are
close, at least for these 3 copolymers. The difference is less than
or equal to 0.5 wt %. The values of r.sub.1 and r.sub.2 denote the
reactivity ratios, which represent the ratios of the rate constants
describing the addition of a like monomer relative to an unlike
monomer.
[0079] If the r.sub.1r.sub.2 value is less than unity as measured
for sample 1, it represents more alternating or random sequences.
If r.sub.1 and r.sub.2 are both large but not infinite, as shown
for sample 2 and sample 3, then block or blocky copolymers will be
produced, or perhaps some homopolymers may be present, depending on
how large the reactivity ratios are and the relative concentration
of the monomers in the feed. Additionally, individual reactivity
ratios were estimated from continuous polymerization reactor data
(experiments from Table 1 plus additional experiments not reported
having a total monomer conversion of 46-53 wt %) using a linear
least squares algorithm to fit the data to the standard copolymer
equation. Using this method, we estimate r.sub.1=5.22,
r.sub.2=0.52, giving r.sub.1r.sub.2=2.71, which is also in good
agreement with the reported .sup.13C NMR results.
TABLE-US-00002 TABLE 1 Process Condition and Characterization of
Some mEPCs Prepared with catalyst 1/activator 1 Sample #: 2 4 5 6 7
8 3 Temperature, .degree. C. 80 80 80 80 80 80 80 Pressure, psig
320 320 320 320 320 320 320 Feed C.sub.2, g/min 2.40 3.12 2.76 2.40
2.03 3.12 3.12 Feed C.sub.3, g/min 3.60 4.80 4.20 3.60 3.00 4.80
4.80 Solvent (isohexane), g/min 61.23 61.23 61.23 61.23 61.23 61.23
61.23 catalyst 1, mol/min 7.34 .times. 10.sup.-8 7.34 .times.
10.sup.-8 7.34 .times. 10.sup.-8 7.34 .times. 10.sup.-8 7.34
.times. 10.sup.-8 6.43 .times. 10.sup.-8 5.51 .times. 10.sup.-8
activator 1, mol/min 7.49 .times. 10.sup.-8 7.49 .times. 10.sup.-8
7.49 .times. 10.sup.-8 7.49 .times. 10.sup.-8 7.49 .times.
10.sup.-8 6.56 .times. 10.sup.-8 5.62 .times. 10.sup.-8 Catalyst
Activity (g/g) 74,700 114,863 96,187 80,550 66,488 109,286 115,500
Polymer C.sub.2, Wt % (FTIR) 53.3 50.9 51.9 52.3 52.8 53.4 54.8 LS
M.sub.w, kg/mol 240 240 224 201 172 233 235 DRI M.sub.w/M.sub.n
2.26 2.44 2.34 2.36 2.41 2.40 2.60 g'.sub.vis 0.889 0.865 0.884
0.878 0.878 0.913 0.933 GPC-3D Mass 90 94 95 94 97 99 100 Recovery,
% ML 47 50 59 48 38 68 82 MLRA 326 529 500 368 276 543 604 T.sub.m,
.degree. C. -2.7 -1.7 -7.6 -7.9 -6.2 -1.8 1.3 H.sub.f, J/g 17 11 18
17 17 22 23
TABLE-US-00003 TABLE 2 .sup.13C NMR Results of mEPCs Sample 1 2 3
Catalyst/Activator 2/2 1/1 1/1 Mol % C.sub.2 (NMR) 65.6 63.0 64.8
Mol % C.sub.3 (NMR) 34.4 37.0 35.2 Wt % C.sub.2 (NMR) 56.0 53.2
55.2 Wt % C.sub.3 (NMR) 44.0 46.8 44.8 Wt % C.sub.2 (FTIR) 55.5
53.3 54.8 Wt % C.sub.3 (FTIR) 44.5 46.7 45.2 Average Sequence 5.9
8.2 8.5 Length for Methylene Sequences Two and Longer Average
Sequence 10.3 12.7 13.2 Length for Methylene Sequences Six and
Longer r.sub.1r.sub.2 0.41 2.8 2.8
TABLE-US-00004 TABLE 2a Methylene Sequence Length Distribution
Methylene Sequence Percentage of Sequences of Length N of Length
(N) sample 1 sample 2 sample 3 2 1 1 1 3 42 27 27 4 1 <1 <1 5
23 23 23 6+ 31 48 49
[0080] Tables 2 and 2a contain chain punctuation data determined
from .sup.13C NMR spectra. Chain punctuation can be evaluated using
the Run# which represents the number of times that a comonomer
changes from one type to the other per 100 monomers. At a given
comonomer level a lower Run# indicates that the comonomer is more
blocked. Blockiness can also be evaluated by calculating an average
methylene sequence length which is determined by dividing the
methylene content by the total number of sequences. Therefore, at a
particular methylene concentration the average sequence length will
necessarily be longer with a lower number of methylene runs or
sequences. In Table 2 average sequence length for all methylene
sequences 2 and longer and 6 and longer are shown. Sample 1 made
with the catalyst 2/activator 2 catalyst system has shorter
methylene sequences on average than samples made with catalyst
1/activator 1. The longer sequences in the catalyst 1/activator 1
polymers correlate with their higher level of crystallinity
relative to the catalyst 2/activator 2 sample.
[0081] Table 2a contains the methylene sequence length distribution
in the copolymers determined by .sup.13C NMR. Sample 1 made with
catalyst 2/activator 2 has a more even distribution of sequences
relative the catalyst 1/activator 1 polymers. Catalyst 1/activator
1 samples have a lower percentage of shorter sequences and a higher
amount of longer ones compared to the catalyst 2/activator 2
polymer. The greater proportion of longer sequences in the catalyst
1/activator 1 polymers is consistent with them having more
crystallinity compared to the catalyst 2/activator 2 polymer.
[0082] FIGS. 3-5 show the GPC-3D traces of the 3 mEPCs described in
Table 2. No shoulders or extra peaks that would cause the higher
T.sub.m values for the two mEPCs prepared with catalyst 1/activator
1 were noted.
[0083] Table 3 shows the GPC-3D, ML and MLRA results of a set of
mEPCs made by catalyst 2/activator 2 or catalyst 1/activator 1.
These mEPCs have similar molecular weights or ML and similar
C.sub.2 contents. These copolymers have essentially no gel because
the values of GPC-3D mass recovery are all greater than or equal to
90%. The mEPCs made by catalyst 1/activator 1 show more branching,
as indicated by small values of g' and a larger values of MLRA. The
larger MLRA is due to the fact that, after the release of an
applied deformation in the Mooney rheometer, the branched mEPC
takes a longer time to relax relative to a linear mEPC, leading to
a larger relaxation area under the Mooney torque curve. At similar
molecular weights, the mEPCs prepared with catalyst 1/activator 1
also have larger values of tensile strength and elongation at break
than the mEPC prepared with catalyst 2/activator 2, FIG. 6.
TABLE-US-00005 TABLE 3 GPC-3D and Mooney Viscosity of mEPCs LS LS
GPC-3D C.sub.2, Catalyst/ M.sub.n, M.sub.w, DRI Mass Re- Wt %
Sample Activator kg/mol kg/mol M.sub.w/M.sub.n g' covery, % (FTIR)
ML MLRA 9 2/2 78 152 2.05 0.993 95 56.3 38 126 7 1/1 73 172 2.41
0.878 97 52.8 38 276 10 1/1 65 144 2.52 0.875 100 52.8 29 177
[0084] Additional evidence for the existence of branch structure in
mEPCs prepared with catalyst 1/activator 1 is based on .sup.1H NMR
results shown in Table 4, where N is the number of terminal double
bonds per chain by assuming any double bond detected by .sup.1H NMR
is at the chain end. The value of N can be determined by the
following equation:
N=[(vinyls/1000C)/1,000](M.sub.n/14)
[0085] The N value of mEPC made using catalyst 1/activator 1 is
much higher than that from the catalyst 2/activator 2 sample. There
are 75 chains containing the terminal double bond in every 100
chains of the catalyst 1/activator 1-derived mEPC. For the mEPC
made with the catalyst 2/activator 2 catalyst system, there are
only 4 chains containing the terminal double bond in every 100
chains. The greater number of chains terminating with a double bond
can result in more branching by increasing the probability of
polymer reincorporation during polymerization.
TABLE-US-00006 TABLE 4 Proton NMR Results of mEPCs GPC-3D Catalyst/
LS M.sub.n, Mass Re- Vinyls/ Sample Activator kg/mol g' covery, %
1,000 C N 11 2/2 38 0.963 92 0.02 0.05 2 1/1 88 0.889 90 0.12
0.75
[0086] Another method to detect the existence of branch structure
in these mEPCs is based on small-strain rheology as shown in FIGS.
7a and 7b for the samples prepared using the catalyst 1/activator 1
and catalyst 2/activator 2 catalyst, respectively. In these
rheological measurements, the test temperature was 190.degree. C.
and the shear strain applied was 10%. The complex modulus (G*), the
phase angle (.delta.), and the complex viscosity (.eta.*) were
measured as the frequency was varied from 0.01 to 100 rad/s. The
plots of phase angle versus the complex modulus in FIGS. 7a and 7b
are known as the Van Gurp-Palmen plots (Please see M. Van Gurp, J.
Palmen, Rheol. Bull., 1998, 67, 5-8). The lower the .delta., the
higher is the melt elasticity or melt strength. Because FIGS. 7a
and 7b are in the same scale, it is evident that the phase angles
are lower for mEPCs from catalyst 1/activator 1 than from catalyst
2/activator 2 in the region of G* from 10,000 to 100,000 Pa.
Therefore, the former set of mEPCs has higher melt strength. The
dependence of complex viscosity as a function of frequency can also
be determined from these rheological measurements at 190.degree.
C., FIGS. 8a and 8b. The following ratio:
[.eta.*(0.1 rds)-.eta.*(100 rds)]/.eta.*(0.1 rds)
was used to measure the degree of shear thinning of the polymeric
materials of the embodiments herein, where .eta.*(0.1 rds) and
.eta.*(100 rds) are the complex viscosities at frequencies of 0.1
and 100 rds, respectively, measured at 190.degree. C. The higher
this ratio, the higher is the degree of shear thinning. The ratios
for the mEPCs prepared with catalyst 1/activator 1 range from 0.987
to 0.993, whereas those prepared with catalyst 2/activator 2 range
from 0.957 to 0.973. Therefore, the former set of mEPCs has higher
degrees of shear thinning, hence better melt processability.
[0087] In terms of application, the mEPC prepared with catalyst
1/activator 1 will be a better compatibilizer for the blends of
ethylene-based polymers or copolymers and propylene-based polymers
or copolymers than the mEPC prepared with catalyst 2/activator 2
because the former type of mEPC has both a longer ethylene sequence
and a branched topology.
[0088] Examples 12, 13 and 14 were made as above and described in
Table 5. This data corresponds to the data in FIGS. 7b and 8b,
where Samples 12, 13, and 14 from top to bottom in the legend.
TABLE-US-00007 TABLE 5 Cat GPC-3D Activity LS M.sub.w, DRI Mass Re-
C.sub.2, ENB, T.sub.m, H.sub.f, T.sub.g, Sample Cat (g/g) kg/mol
M.sub.w/M.sub.n g' covery, % Wt % Wt % .degree. C. J/g .degree. C.
ML MLRA 12 2/2 125,625 243 2.12 1.009 93 62.3 0 -6.0 25 -48 104 317
13 2/2 120,750 211 2.10 1.011 93 60.6 0 -11 23 -50 81 264 14 2/2
107,719 188 1.99 0.993 94 60.1 0 -16 21 -52 57 192
* * * * *