U.S. patent application number 10/719381 was filed with the patent office on 2004-06-24 for shear thinning ethylene/alpha-olefin interpolymers and their preparation.
Invention is credited to Cady, Larry Duane, Hughes, Morgan Mark, Laughner, Michael Kenneth, Meiske, Larry Alan, Parikh, Deepak Rasiklal.
Application Number | 20040122190 10/719381 |
Document ID | / |
Family ID | 30002539 |
Filed Date | 2004-06-24 |
United States Patent
Application |
20040122190 |
Kind Code |
A1 |
Cady, Larry Duane ; et
al. |
June 24, 2004 |
Shear thinning ethylene/alpha-olefin interpolymers and their
preparation
Abstract
Shear-thinning ethylene/.alpha.-olefin and
ethylene/.alpha.-olefin/diene monomer interpolymers that do not
include a traditional branch-inducing monomer such as norbornadiene
are prepared at an elevated temperature in an atmosphere that has
little or no hydrogen using a constrained geometry complex catalyst
and an activating cocatalyst.
Inventors: |
Cady, Larry Duane; (Houston,
TX) ; Hughes, Morgan Mark; (Angelton, TX) ;
Laughner, Michael Kenneth; (Lake Jackson, TX) ;
Meiske, Larry Alan; (Baton Rouge, LA) ; Parikh,
Deepak Rasiklal; (Lake Jackson, TX) |
Correspondence
Address: |
DUPONT DOW ELASTOMERS, LLC
PATENT RECORDS CENTER
4417 LANCASTER PIKE
BARLEY MILL PLAZA 25
WILMINGTON
DE
19805
US
|
Family ID: |
30002539 |
Appl. No.: |
10/719381 |
Filed: |
November 20, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10719381 |
Nov 20, 2003 |
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09830936 |
May 2, 2001 |
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6680361 |
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09830936 |
May 2, 2001 |
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PCT/US99/25637 |
Nov 2, 1999 |
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60106569 |
Nov 2, 1998 |
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Current U.S.
Class: |
526/126 ;
524/543; 526/134; 526/348.5; 526/348.6; 526/351; 526/905 |
Current CPC
Class: |
C08F 4/65908 20130101;
C08L 23/10 20130101; C08L 23/16 20130101; C08F 2500/25 20130101;
C08F 2500/17 20130101; C08F 210/06 20130101; C08L 2666/04 20130101;
C08F 210/18 20130101; Y10S 526/943 20130101; C08F 210/16 20130101;
Y10S 526/905 20130101; C08L 23/10 20130101; Y10S 526/916 20130101;
C08F 4/65912 20130101; C08L 23/16 20130101; C08F 10/00 20130101;
C08F 210/18 20130101; C08F 2500/19 20130101; C08F 4/6592 20130101;
C08F 10/00 20130101; C08F 2500/03 20130101; C08L 2666/04
20130101 |
Class at
Publication: |
526/126 ;
526/905; 526/134; 526/348.5; 526/351; 526/348.6; 524/543 |
International
Class: |
C08F 004/44 |
Claims
1. A shear thinning ethylene/.alpha.-olefin interpolymer, the
interpolymer having polymerized therein ethylene, at least one
.alpha.-olefin monomer and, optionally, at least one diene monomer
and being characterized by a Processing Rheology Ratio (PRR) of at
least four, where PRR=(interpolymer Viscosity measured at
190.degree. C. with a shear rate of 0.1 rad/sec)/(interpolymer
Viscosity measured at 190.degree. C. with a shear rate of 100
rad/sec)+[3.82-interpolymer Mooney Viscosity (ML.sub.1+4 @
125.degree. C.)].times.0.3.
2. The interpolymer of claim 1, wherein the interpolymer has (a) a
weight ratio of ethylene to .alpha.-olefin within a range of from
90:10 to 10:90, the .alpha.-olefin being a C.sub.3-20
.alpha.-olefin and (b) a diene monomer content within a range of
from 0 to 25 percent by weight, based on interpolymer weight.
3. The interpolymer of claim 1, wherein the interpolymer has a
Mooney Viscosity (ML.sub.1+4 at 125.degree. C.) within a range of
from 0.5 to about 200.
4. The interpolymer of claim 1, wherein the interpolymer has a
molecular weight distribution (Mw/Mn) of at least 2.0.
5. The interpolymer of claim 4, wherein the molecular weight
distribution is at least 2.5 and the PRR is at least 8.
6. The interpolymer of claim 1, wherein the interpolymer is an
EAODM interpolymer with a molecular weight distribution of at least
2.3, a Mooney Viscosity (ML.sub.1+4 at 125.degree. C.) of at least
15 and a PRR of at least 20.
7. The interpolymer of claim 1, wherein the interpolymer is an
ethylene/octene-1 copolymer with a molecular weight distribution of
at least 2.3, a Mooney Viscosity (ML.sub.1+4 at 125.degree. C.) of
at least 5.
8. The interpolymer of claim 2, wherein the alpha-olefin is
selected from the group consisting of propylene, butene-1,
pentene-1,4-methyl-pentene-1- , hexene-1, octene-1, styrene,
p-methyl styrene and mixtures thereof, and the optional diene
monomer is selected from the group consisting of
5-ethylidene-2-norbornene, 5-vinylidene-2-norbornene,
5-methylene-2-norbornene, 1,4-hexadiene, 1,3-pentadiene,
7-methyl-1,6-octadiene, 1,3-butadiene, 4-methyl-1,3-pentadiene,
5-methyl-1,4-hexadiene, 6-methyl-1,5-heptadiene and mixtures
thereof.
9. The interpolymer of claim 2, further comprising a PRR enhancing
amount of an additional diene monomer, the additional diene monomer
being selected from the group consisting of dicyclopentadiene,
norbornadiene, 1,7-octadiene, and 1,9-decadiene.
10. A process for preparing ethylene/.alpha.-olefin interpolymer of
claim 1, the process comprising: contacting ethylene, at least one
.alpha.-olefin monomer and, optionally, at least one diene monomer
with a catalyst and an activating cocatalyst under conditions
sufficient to attain an ethylene conversion of at least 60 weight
percent, the conditions including a temperature of at least
70.degree. C. and, optionally, in the presence of an effective
amount of hydrogen, the amount being sufficient to maintain an
interpolymer PRR of at least 4, the catalyst being a constrained
geometry metal complex
11. The process of claim 10, wherein the amount of hydrogen is
greater than 0 mole percent, but less than 0.10 mole percent, based
upon total monomer content plus hydrogen content.
12. The process of claim 10, wherein the amount of hydrogen is
greater than 0 mole percent, but less than 0.05 mole percent, based
upon total monomer content plus hydrogen content.
13. The process of claim 10, wherein the catalyst is selected from
the group consisting of (t-butyl-amido)-dimethyl
(.eta..sup.5-2-methyl-s-inda- cen-1-yl)silane-titanium (IV)
dimethyl, (t-butylamido)-dimethyl-(.eta..sup-
.5-2-methyl-s-indacen-1-yl)silane-titanium (II) 1,3-pentadiene and
(t-butylamido)dimethyl-(.eta..sup.5-2-methyl-s-indacen-1-yl)silanetitaniu-
m (II) 2,4-hexadiene or a Group B catalyst selected from
(t-butylamido)-dimethyl(.eta..sup.5-2,3-dimethylindenyl)silanetitanium
(II) 1,4-diphenyl-1,3-butadiene,
(t-butyl-amido)-dimethyl(.eta..sup.5-2,3-
-dimethyl-s-indacen-1-yl)silanetitanium (IV) dimethyl and mixtures
thereof.
14. The process of claim 10, wherein the activating cocatalyst is
trispentafluorophenyl borane.
15. The process of claim 10, wherein the interpolymer has an
ethylene content of from 20 to 95 weight percent (wt %), an
.alpha.-olefin content of from 80 to 5 wt %, the .alpha.-olefin
being a C.sub.3-20 .alpha.-olefin and, optionally a diene monomer
content within a range of from 0 to 25 percent by weight, all
percentages based on interpolymer weight and totaling 100 wt %.
16. The process of claim 10, wherein the interpolymer is
amorphous.
17. The process of claim 10, wherein the interpolymer is at least
partially crystalline and the temperature is at least 80.degree. C.
and the ethylene conversion is at least 80%.
18. An article of manufacture having at least one portion thereof
fabricated from a composition that comprises the interpolymer of
claim 1.
19. The article of claim 18, wherein the article is selected from
the group consisting of wire and cable components, electrical
insulation, belts, hoses, tubes, gaskets, membranes, molded goods,
extruded parts, automotive parts, adhesives, tire walls and
tires.
20. The article of claim 18, wherein the composition further
comprises at least one additive selected from the group consisting
of fillers, fibers, plasticizers, oils, colorants, stabilizers,
foaming agents, retarders, accelerators, and cross-linking
agents.
21. An polymer blend composition, the composition comprising more
than 50 parts by weight of a crystalline polyolefin resin and less
than 50 parts by weight of the interpolymer of claim 1, the total
amount of crystalline polyolefin resin and interpolymer being 100
parts by weight.
22. A thermoplastic vulcanizate composition, the composition
comprising from 60 to less than 10 parts by weight of a crystalline
polyolefin resin and from 40 to more than 90 parts by weight of the
interpolymer of claim 1 wherein the interpolymer is at least
partially cross-linked such that the composition has a gel content
of at least 70%, based on interpolymer weight, the total amount of
crystalline polyolefin resin and interpolymer being 100 parts by
weight.
23. The composition of claim 21 or 22, wherein the crystalline
polyolefin resin is a polypropylene homopolymer, a copolymer of
propylene with an .alpha.-olefin selected from the group consisting
of ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene,
2-methyl-1-propene or 4-methyl-1-pentene, or a blend of a
polypropylene homopolymer and a propylene/.alpha.-olefin copolymer
or a mixture thereof.
24. The composition of claim 23, wherein the .alpha.-olefin is
ethylene.
25. An article of manufacture fabricated from the composition of
any of claims 21-24.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to shear thinning
ethylene/.alpha.-olefin (EAO) interpolymers. The interpolymers have
a Processing Rheology Ratio (PRR) of at least 4, an indication that
long chain branching (LCB) is present. The interpolymers attain
such a PRR in the absence of a conventional LCB monomer such as
norbornadiene NBD). The alpha-olefin (.alpha.-olefin) suitably
contains three to 20 carbon atoms (C.sub.3-C.sub.20) and is
preferably propylene (C.sub.3), 1-butene, 1-hexene or 1-octene
(C.sub.8). The interpolymers desirably include a diene (diolefin)
monomer, preferably a nonconjugated diene monomer such as
5-ethylidene-2-norbornene (ENB). The diene-containing EAO
interpolymers are generically referred to as "EAODM interpolymers".
EAO and EAODM interpolymers are collectively referred to as
"EAO(D)M interpolymers". This invention also relates to preparation
of such interpolymers, compositions that include such interpolymers
and articles of manufacture that include at least one part or
portion fabricated from such interpolymers or compositions.
SUMMARY OF THE INVENTION
[0002] A first aspect of the invention is a shear thinning EAO(D)M
interpolymer, the interpolymer having polymerized therein ethylene,
at least one .alpha.-olefin monomer and, optionally, at least one
diene monomer and being characterized by a PRR of at least four.
The interpolymer desirably has an ethylene (C.sub.2) content of
from 20 to 95 weight percent (wt %), an .alpha.-olefin content of
from 80 to 5 wt %, the .alpha.-olefin being a C.sub.3-20
.alpha.-olefin and, optionally, a diene monomer content within a
range of from greater than 0 to 25 wt %, all percentages being
based on interpolymer weight and totaling 100 wt %. The EAO(D)M
interpolymer attains such a PRR in the absence of NBD or any other
conventional LCB monomer.
[0003] Interpolymer viscosity is conveniently measured in poise
(dyne-second/square centimeter (d-sec/cm.sup.2)) at shear rates
within a range of 0.1-100 radian per second (rad/sec) and at
190.degree. C. under a nitrogen atmosphere using a dynamic
mechanical spectrometer such as a RMS-800 or ARES from Rheometrics.
The viscosities at 0.1 rad/sec and 100 rad/sec may be represented,
respectively, as V.sub.0.1 and V.sub.100 with a ratio of the two
referred to as RR and expressed as V.sub.0.1/V.sub.100.
PRR=RR+[3.82-interpolymer Mooney Viscosity (ML.sub.1+4 at
125.degree. C.)].times.0.3.
[0004] A second aspect of the invention is a process for preparing
the EAO(D)M interpolymer of the first aspect, the process
comprising: contacting ethylene, at least one .alpha.-olefin
monomer and, optionally, at least one diene monomer with a catalyst
and an activating cocatalyst under conditions sufficient to attain
an ethylene conversion of at least 60 weight percent, the
conditions including a temperature of at least 70.degree. C., more
preferably at least 80.degree. C., and, optionally, in the presence
of an effective amount of hydrogen, the amount being sufficient to
maintain an interpolymer PRR of at least 4, the catalyst being at
least one constrained geometry metal complex. The .alpha.-olefin
monomer is suitably a C.sub.3-20 .alpha.-olefin monomer. The
process is especially useful for the solution polymerization of
EAO(D)M interpolymers wherein the diene or polyene is ENB,
1,4-hexadiene or a similar nonconjugated diene or a conjugated
diene such as 1,3-pentadiene. The diene is preferably ENB or
7-methyl-1,6-octadiene. As in the first aspect, the interpolymer
PRR is achieved in the absence of a conventional LCB monomer.
[0005] A third aspect of the invention is a polymer blend
composition that comprises the interpolymer of the first aspect and
an amount of a crystalline polyolefin resin, desirably a propylene
polymer or copolymer, preferably polypropylene (PP). The
interpolymer is desirably present in an amount of less than 50
parts by weight (pbw) and the crystalline polyolefin resin is
desirably present in an amount of more than 50 pbw. When the
interpolymer is an EAODM interpolymer, the polymer blend is
referred to as a thermoplastic elastomer or TPE. When the
interpolymer is an EAO interpolymer, the polymer blend is referred
to as a thermoplastic polyolefin or TPO.
[0006] A fourth aspect of the invention is a polymer blend
composition that comprises an interpolymer of the first aspect that
is at least partially crosslinked (also referred to as cured or
vulcanized) and a crystalline polyolefin resin, again desirably a
propylene polymer or copolymer, preferably PP. The interpolymer is
desirably present in an amount of from 40 to 90 pbw and the
crystalline polyolefin is desirably present in an amount of from 60
to 10 pbw. The interpolymer is preferably crosslinked sufficiently
to provide a gel content of at least 70%, based on interpolymer
weight.
[0007] In both the third and fourth aspects, the amounts of
interpolymer and crystalline polyolefin resin are based on total
weight of interpolymer plus crystalline polyolefin and, when added
together, equal 100 pbw.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0008] All references to the Periodic Table of the Elements herein
refer to the Periodic Table of the Elements, published and
copyrighted by CRC Press, Inc., 1989. Also, any reference to a
Group or Groups shall be to the Group or Groups as reflected in
this Periodic Table of the Elements using the IUPAC system for
numbering groups.
[0009] Neat EAO(D)M interpolymers of the present invention have
three distinct characteristics. One is a PRR of at least four. The
PRR is desirably within a range of from 4 to 350, preferably from 4
to 250, most preferably from 8 to 150. A second is a Mooney
Viscosity or MV (ML.sub.1+4 @125.degree. C., ASTM D1646-94) within
a range of from 0.5 to 200, preferably from 5 to 120, and more
preferably from 10 to 85. A third is a molecular weight
distribution (MWD or M.sub.w/M.sub.n) within a range of from 2 to
5, preferably from 2.0 to 3.8, and more preferably from 2.2 to 3.2.
Given these characteristics, preferred EAO(D)M interpolymers have a
MWD of at least 2.5 and a PRR of at least 8. Preferred EAODM
interpolymers have a MWD of at least 2.2, a MV of at least 15 and a
PRR of at least 10. When the EAO is a C.sub.2/C.sub.8 (EO)
copolymer, the MWD is at least 2.3, the MV is at least 5 and the
PRR is preferably greater than 4.
[0010] In solution polymerization processes, a known and
predominant mode of controlling molecular weight is chain
termination via thermal termination, hydrogen termination or both.
It is believed that thermal termination yields a chain end with a
reactive vinyl group whereas hydrogen chain termination yields a
non-reactive saturated end group. In most cases, thermal
termination competes with hydrogen termination. It is also believed
that the formation of reactive vinyl end groups and subsequent
reinsertion thereof into a growing polymer backbone under the
process conditions detailed above yields a polymer product with in
situ LCB. As such, reactor condition combinations that favor
forming reactive vinyl end groups, such as little or no hydrogen
and elevated polymerization temperatures, are believed to favor
incorporation of the reactive vinyl end groups which in turn leads
to an increased LCB level as reflected by a PRR increase.
[0011] The EAO(D)M interpolymers of the present invention have
polymerized therein C.sub.2, at least one C.sub.3-20 .alpha.-olefin
(ethylenically unsaturated) monomer and, optionally, a C.sub.4-40
diene monomer (other than NBD or another conventional LCB monomer).
The .alpha.-olefin may be either an aliphatic or an aromatic
compound and may contain vinylic unsaturation or a cyclic compound,
such as styrene, p-methyl styrene, cyclobutene, cyclopentene, and
norbornene, including norbornene substituted in the 5 and 6
position with C.sub.1-20 hydrocarbyl groups. The .alpha.-olefin is
preferably a C.sub.3-20 aliphatic compound, more preferably a
C.sub.3-16 aliphatic compound. Preferred ethylenically unsaturated
monomers include 4-vinylcyclohexene, vinylcyclohexane, and
C.sub.3-10 aliphatic .alpha.-olefins (especially ethylene,
propylene, isobutylene, 1-butene, 1-pentene, 1-hexene,
3-methyl-1-pentene, 4-methyl-1-pentene, 1-octene, 1-decene and
1-dodecene). A more preferred C.sub.3-10 aliphatic .alpha.-olefin
is selected from the group consisting of propylene, 1-butene,
1-hexene and 1-octene.
[0012] The interpolymers of the present invention have a C.sub.2
content of from 20 up to 95 wt %, more preferably 30 to 93 wt %,
and most preferably 35 to 90 wt %. The interpolymers also contain
at least one .alpha.-olefin, other than C.sub.2, at a level of 5 to
80 wt %, more preferably at 7 to 70 wt %, and most preferably from
10 to 65 wt %. Finally, the interpolymers may include a
non-conjugated diene. When the interpolymers include a
non-conjugated diene, the non-conjugated diene content is
preferably from greater than 0 to 25 wt % or higher, more
preferably from greater than 0 to 15 wt %, and most preferably from
greater than 0 to 10 wt %. All percentages are based on
interpolymer weight. If desired, more than one diene may be
incorporated simultaneously, for example 1,4-hexadiene and ENB,
with total diene incorporation within the limits specified
above.
[0013] The C.sub.4-40 diolefin or diene monomer is desirably a
non-conjugated diolefin that is conventionally used as a cure site
for cross-linking. The nonconjugated diolefin can be a C.sub.6-15
straight chain, branched chain or cyclic hydrocarbon diene.
Illustrative nonconjugated dienes are straight chain acyclic dienes
such as 1,4-hexadiene and 1,5-heptadiene; branched chain acyclic
dienes such as 5-methyl-1,4-hexadiene, 2-methyl-1,5-hexadiene,
6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene,
3,7-dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene,
5,7-dimethyl-1,7-octadiene, 1,9-decadiene and mixed isomers of
dihydromyrcene; single ring alicyclic dienes such as
1,4-cyclohexadiene, 1,5-cyclooctadiene and 1,5-cyclododecadiene;
multi-ring alicyclic fused and bridged ring dienes such as
tetrahydroindene, methyl tetrahydroindene; alkenyl, alkylidene,
cycloalkenyl and cycloalkylidene norbornenes such as
5-methylene-2-norbornene (MNB), ENB, 5-vinyl-2-norbornene,
5-propenyl-2-norbornene, 5-isopropylidene-2-norbornene,
5-(4-cyclopentenyl)-2-norbornene and
5-cyclohexylidene-2-norbornene. The diene is preferably a
nonconjugated diene selected from the group consisting of ENB and
1,4-hexadiene, 7-methyl-1,6-octadiene, more preferably, ENB. The
diolefin may, however, be a conjugated diene selected from the
group consisting of 1,3-pentadiene, 1,3-butadiene,
2-methyl-1,3-butadiene, 4-methyl-1,3-pentadiene, or
1,3-cyclopentadiene. The EAODM diene monomer content, whether it
comprise a conjugated diene, a non-conjugated diene or both, falls
within the limits specified above for non-conjugated dienes.
[0014] Although preferred interpolymers are substantially free of
any diene monomer that typically induces LCB, one may include such
a monomer if costs are acceptable and desirable interpolymer
properties, such as processibility, tensile strength and
elongation, do not degrade to an unacceptable level. Such diene
monomers include dicyclopentadiene, NBD, methyl norbornadiene,
vinyl-norbornene, 1,6-octadiene, 1,7-octadiene, and 1,9-decadiene.
When added, such monomers are added in an amount within a range of
from greater than zero to 3 wt %, more preferably from greater than
zero to 2 wt %, based on interpolymer weight.
[0015] The interpolymers of the present invention may be used in
preparing any of a variety of articles or manufacture or their
component parts or portions. For purposes of illustration only, and
not by way of limitation, such articles may be selected from the
group consisting of wire and cable components, electrical
insulation, belts, hoses, tubes, gaskets, membranes, molded goods,
extruded parts, automotive parts, adhesives, tires and tire
sidewalls.
[0016] The interpolymers of the present invention may be used as
is, but preferably find use as a component of a compound. A
compound typically comprises at least one polymer in admixture with
at least one additive selected from the group consisting of
fillers, fibers, plasticizers, oils, colorants, stabilizers,
foaming agents, retarders, accelerators, cross-linking agents and
other conventional additives. The interpolymers of the present
invention preferably comprise at least part of the polymer content
of such a compound.
[0017] Interpolymers, and compounds containing such an
interpolymer, may be converted into a finished article of
manufacture by any one of a number of conventional processes and
apparatus. Illustrative processes include extrusion, calendering,
injection molding, compression molding, fiber spinning, and other
typical thermoplastic processes.
[0018] The interpolymers of the present invention may also serve as
a base polymer in preparing a graft polymer. Any unsaturated
organic compound that contains at least one ethylenic unsaturation
(at least one double bond), and will graft to an interpolymer of
the present invention can be used to modify such an interpolymer.
Illustrative unsaturated compounds include vinyl ethers,
vinyl-substituted heterocyclic compounds, vinyl oxazolines, vinyl
amines, vinyl epoxies, unsaturated epoxy compounds, unsaturated
carboxylic acids, and anhydrides, ethers, amines, amides,
succinimides or esters of such acids. Representative compounds
include maleic, fumaric, acrylic, methacrylic, itaconic, crotonic,
.alpha.-methyl crotonic, and cinnamic acid and their anhydride,
ester or ether derivatives, vinyl-substituted alkylphenols and
glycidyl methacrylates. Suitable unsaturated amines include those
of aliphatic and heterocyclic organic nitrogen compounds that
contain at least one double bond and at least one amine group (at
least one primary, secondary or tertiary amine). Maleic anhydride
is the preferred unsaturated organic compound. Grafted
interpolymers may be used in a number of applications, only one of
which is as a component of an oleaginous compound. The use of a
grafted EPDM interpolymer in oleaginous compositions, procedures
used to prepare such grafted interpolymers and various graft
moieties are disclosed in WO 97/32946 (based on U.S. priority
documents 60/013,052 of 8 Mar. 1996 and 60/024,913 of 30 Aug.
1996), the relevant teachings of which, or the corresponding
equivalent United States application, are incorporated herein by
reference.
[0019] As noted in the third and fourth aspects, the interpolymers
may be used in preparing a TPE, a TPO or a TPV. A number of
references provide general procedures for preparing a TPE. One such
reference is EP 751,182, published 2 Jan. 1997, the relevant
teachings of which are incorporated herein by reference.
[0020] Olefins that may be used to prepare crystalline polyolefin
resins include one or more of ethylene, propylene, 1-butene,
1-pentene, 1-hexene, 1-octene, 1-decene, 2-methyl-1-propene,
3-methyl-1-pentene, and 4-methyl-1-pentene. The crystalline
polyolefin is desirably a PP homopolymer or a copolymer of
propylene with an .alpha.-olefin such as ethylene, 1-butene,
1-hexene or 4-methyl-1-pentene or a blend of a homopolymer and a
copolymer. The .alpha.-olefin is preferably ethylene. The
crystalline polyolefins may be prepared by any suitable process
such as random polymerization or block polymerization. Various
forms such as isotactic and syndiotactic may also be used. Typical
commercially available crystalline resins include PP homopolymer
and propylene/ethylene (P/E) copolymer resins. Certain of the
olefin copolymer resins, especially propylene copolymers such as
the P/E copolymers, may be referred to as "semi-crystalline"
resins. The use of "crystalline" to describe polyolefin resins is
meant to be broad enough to include such semi-crystalline resins.
The crystalline resins may be used singly or in combination.
[0021] Preparation of PP homopolymers and P/E copolymers also
involves the use of Ziegler catalysts such as a titanium
trichloride in combination with aluminum diethylmonochloride, as
described by Cecchin, U.S. Pat. No. 4,177,160. Polymerization
processes used to produce PP include the slurry process, which is
run at about 50-90.degree. C. and 0.5-1.5 MPa (5-15 atm), and both
the gas-phase and liquid-monomer processes in which extra care must
be given to the removal of amorphous polymer. Ethylene may be added
to the reaction to form a polypropylene with ethylene blocks. PP
resins may also be prepared by using any of a variety of
metallocene, single site and constrained geometry catalysts
together with their associated processes.
[0022] A number of patents and publications disclose constrained
geometry metal complexes and methods for their preparation. An
illustrative, but not exhaustive, list includes EP-A-416,815 (U.S.
Ser. No. 545,403, filed Jul. 3, 1990); EP-A-468,651 (U.S. Ser. No.
547,718, filed Jul. 3, 1990); EP-A-514,828 (U.S. Ser. No. 702,475,
filed May 20, 1991); EP-A-520,732 (U.S. Ser. No. 876,268, filed May
1, 1992) and WO93/19104 (U.S. Ser. No. 8,003, filed Jan. 21, 1993),
as well as U.S. Pat. No. 5,055,438, U.S. Pat. No. 5,057,475, U.S.
Pat. No. 5,096,867, U.S. Pat. No. 5,064,802, U.S. Pat. No.
5,132,380, U.S. Pat. No. 5,470,993, U.S. Pat. No. 5,556,928, U.S.
Pat. No. 5,624,878, WO95/00526, and US Provisional Application
60-005913. U.S. Ser. No. 592,756, filed Jan. 26, 1996, WO95/14024,
WO 98/27103 (based on U.S. priority documents 60/034,817 of 19 Dec.
1996 and Ser. No. 08/949,505 of 14 Oct. 1997) and PCT/US97/07252
(filed 30 Apr. 1997) disclose various substituted
indenyl-containing metal complexes. The relevant teachings of all
of the foregoing patents and publications, or of the corresponding
equivalent United States application, are hereby incorporated by
reference.
[0023] Broadly speaking, suitable metal complexes for use include
any complex of a metal of Groups 3-10 of the Periodic Table of the
Elements capable of being activated to polymerize addition
polymerizable compounds, especially olefins by the present
activators. Examples include Group 10 diimine derivatives
corresponding to the formula: 1
[0024] M* is Ni(II) or Pd(II); X' is halo, hydrocarbyl, or
hydrocarbyloxy; Ar* is an aryl group, especially
2,6-diisopropylphenyl or aniline group; CT-CT is 1,2-ethanediyl,
2,3-butanediyl, or form a fused ring system wherein the two T
groups together are a 1,8-naphthanediyl group; and A.sup.- is the
anionic component of the foregoing charge separated activators.
[0025] Similar complexes to the foregoing are also disclosed by M.
Brookhart, et al., in J. Am. Chem. Soc., 118, 267-268 (1996) and J.
Am. Chem. Soc., 117, 6414-6415 (1995), as being active
polymerization catalysts especially for polymerization of
.alpha.-olefins, either alone or in combination with polar
comonomers such as vinyl chloride, alkyl acrylates and alkyl
methacrylates.
[0026] Additional complexes include derivatives of Group 3, 4, or
Lanthanide metals containing from 1 to 3 .pi.-bonded anionic or
neutral ligand groups, which may be cyclic or non-cyclic
delocalized .pi.-bonded anionic ligand groups. The term
".pi.-bonded" means that the ligand group is bonded to the
transition metal by a sharing of electrons from a partially
delocalized .pi.-bond.
[0027] Each atom in the delocalized .pi.-bonded group may
independently be substituted with a radical selected from the group
consisting of hydrogen, halogen, hydrocarbyl, halohydrocarbyl,
hydrocarbyloxy, hydrocarbylsulfide, dihydrocarbylamino, and
hydrocarbyl-substituted metalloid radicals wherein the metalloid is
selected from Group 14 of the Periodic Table of the Elements, and
such hydrocarbyl-, halohydrocarbyl-, hydrocarbyloxy-,
hydrocarbylsulfide-, dihydrocarbylamino- or hydrocarbyl-substituted
metalloid-radicals that are further substituted with a Group 15 or
16 hetero atom containing moiety. Included within the term
"hydrocarbyl" are C.sub.1-20 straight, branched and cyclic alkyl
radicals, C.sub.6-20 aromatic radicals, C.sub.7-20
alkyl-substituted aromatic radicals, and C.sub.7-20
aryl-substituted alkyl radicals. In addition, two or more such
radicals may together form a fused ring system, including partially
or fully hydrogenated fused ring systems, or they may form a
metallocycle with the metal. Suitable hydrocarbyl-substituted
organometalloid radicals include mono-, di- and tri-substituted
organometalloid radicals of Group 14 elements wherein each of the
hydrocarbyl groups contains from 1 to 20 carbon atoms. Examples of
suitable hydrocarbyl-substituted organometalloid radicals include
trimethylsilyl, triethylsilyl, ethyldimethylsilyl,
methyldiethylsilyl, triphenylgermyl, and trimethylgermyl groups.
Examples of Group 15 or 16 hetero atom containing moieties include
amine, phosphine, ether or thioether moieties or divalent
derivatives thereof, e.g. amide, phosphide, ether or thioether
groups bonded to the transition metal or Lanthanide metal, and
bonded to the hydrocarbyl group or to the hydrocarbyl-substituted
metalloid containing group.
[0028] Exemplary of such .pi.-bonded anionic ligand groups are
conjugated or nonconjugated, cyclic or non-cyclic dienyl groups,
allyl groups, boratabenzene groups, and arene groups. Examples of
suitable anionic, delocalized .pi.-bonded groups include
cyclopentadienyl, indenyl, fluorenyl, tetrahydroindenyl,
tetrahydrofluorenyl, octahydrofluorenyl, pentadienyl,
cyclohexadienyl, dihydroanthracenyl, hexahydroanthracenyl,
decahydroanthracenyl groups and s-indacenyl, as well as C.sub.1-10
hydrocarbyl-substituted, C.sub.1-10 hydrocarbyloxy-substituted,
di(C.sub.1-10 hydrocarbyl)amino-substituted, or tri(C.sub.1-10
hydrocarbyl)silyl-substituted derivatives thereof. Preferred
anionic delocalized .pi.-bonded groups are cyclopentadienyl,
pentamethylcyclopentadienyl, tetramethylcyclopentadienyl,
tetramethylsilylcyclo-pentadienyl, indenyl, 2,3-dimethylindenyl,
fluorenyl, 2-methylindenyl, 2-methyl-4-phenylindenyl,
tetrahydrofluorenyl, octahydrofluorenyl, s-indacenyl,
2-methyl-s-indacenyl, and tetrahydroindenyl.
[0029] The boratabenzenes are anionic ligands that are
boron-containing analogues to benzene. They are previously known in
the art having been described by G. Herberich, et al., in
Organometallics, 1995, 14, 1, 471-480.
[0030] A first preferred constrained geometry catalyst corresponds
to formula II: 2
[0031] wherein M is titanium, zirconium or hafnium in the +2, +3 or
+4 formal oxidation state; A' is a substituted indenyl group
substituted in at least the 2 position with a group selected from
hydrocarbyl, fluoro-substituted hydrocarbyl,
hydrocarbyloxy-substituted hydrocarbyl, dialkylamino-substituted
hydrocarbyl, silyl, germyl and mixtures thereof, said group
containing up to 40 nonhydrogen atoms, and said A' further being
covalently bonded to M by means of a divalent Z group; Z is a
divalent moiety bound to both A' and M via 1-bonds, said z
comprising boron, or a member of Group 14 of the Periodic Table of
the Elements, and also comprising nitrogen, phosphorus, sulfur or
oxygen; X is an anionic or dianionic ligand group having up to 60
atoms exclusive of the class of ligands that are cyclic,
delocalized, .pi.-bound ligand groups; X' independently each
occurrence is a neutral Lewis base ligating compound, having up to
20 atoms; p is 0, 1 or 2, and is two less than the formal oxidation
state of M, with the proviso that when X is a dianionic ligand
group, p is 1; and q is 0, 1 or 2.
[0032] Additional preferred catalysts or coordination complexes are
disclosed in previously incorporated WO 98/27103 and
PCT/US97/07252. PCT/US97/07252, especially at page 4, line 34
through page 16, line 36, describes preferred coordination
complexes such as those reproduced below as formulae III, IVA and
IVB. Formula I below is a variation of formula II at page 7 of
PCT/US97/07252.
[0033] The catalysts desirably include metal coordination complexes
that correspond to formula I: 3
[0034] where M is defined as in formula II above; R' and R" are
independently each occurrence hydride, hydrocarbyl, silyl, germyl,
halide, hydrocarbyloxy, hydrocarbylsiloxy, hydrocarbylsilylamino,
di(hydrocarbyl)amino, hydrocarbyleneamino,
di(hydrocarbyl)phosphino, hydrocarbylene-phosphino,
hydrocarbylsulfido, halo-substituted hydrocarbyl,
hydrocarbyloxy-substituted hydrocarbyl, silyl-substituted
hydrocarbyl, hydrocarbylsiloxy-substituted hydrocarbyl,
hydrocarbylsilylamino-substituted hydrocarbyl,
di(hydrocarbyl)amino-subst- ituted hydrocarbyl,
hydrocarbyleneamino-substituted hydrocarbyl,
di(hydrocarbyl)phosphino-substituted hydrocarbyl,
hydrocarbylene-phosphin- o-substituted hydrocarbyl, or
hydrocarbylsulfido-substituted hydrocarbyl, said R' or R" group
having up to 40 nonhydrogen atoms, and optionally two or more of
the foregoing groups may together form a divalent derivative; R'"
is a divalent hydrocarbylene- or substituted hydrocarbylene group
forming a fused system with the remainder of the metal complex,
said R'" containing from 1 to 30 nonhydrogen atoms; Z is a divalent
moiety, or a moiety comprising one .sigma.-bond and a neutral two
electron pair able to form a coordinate-covalent bond to M, said Z
comprising boron, or a member of Group 14 of the Periodic Table of
the Elements, and also comprising nitrogen, phosphorus, sulfur or
oxygen; X is a monovalent anionic ligand group having up to 60
atoms exclusive of the class of ligands that are cyclic,
delocalized, .pi.-bound ligand groups; X' independently each
occurrence is a neutral ligating compound having up to 20 atoms; X"
is a divalent anionic ligand group having up to 60 atoms; p is
zero, 1, 2, or 3; q is zero, 1 or 2, and r is zero or 1.
[0035] The above complexes may exist as isolated crystals
optionally in pure form or as a mixture with other complexes, in
the form of a solvated adduct, optionally in a solvent, especially
an organic liquid, as well as in the form of a dimer or chelated
derivative thereof, wherein the chelating agent is an organic
material such as ethylenediaminetetraacetic acid (EDTA).
[0036] In the metal complexes defined in formulae I and II,
preferred X' groups are carbon monoxide; phosphines, especially
trimethylphosphine, triethylphosphine, triphenylphosphine and
bis(1,2-dimethylphosphino)ethan- e; P(OR).sub.3, wherein R is
C.sub.1-20 hydrocarbyl; ethers, especially tetrahydrofuran; amines,
especially pyridine, bipyridine, tetramethylethylenediamine
(TMEDA), and triethylamine; olefins; and neutral conjugated
C.sub.4-40 dienes. Complexes including such neutral diene X' groups
are those wherein the metal is in the +2 formal oxidation
state.
[0037] The catalysts preferably include coordination complexes that
correspond to formula III: 4
[0038] wherein R.sub.1 and R.sub.2, independently are groups
selected from hydrogen, hydrocarbyl, perfluoro substituted
hydrocarbyl, silyl, germyl and mixtures thereof, said group
containing up to 20 non-hydrogen atoms, with the proviso that at
least one of R.sub.1 or R.sub.2 is not hydrogen; R.sub.3, R.sub.4,
R.sub.5 and R.sub.6 independently are groups selected from
hydrogen, hydrocarbyl, perfluoro substituted hydrocarbyl, silyl,
germyl and mixtures thereof, said group containing up to 20
non-hydrogen atoms; M is titanium, zirconium or hafnium; Z is a
divalent moiety comprising boron, or a member of Group 14 of the
Periodic Table of the Elements, and also comprising nitrogen,
phosphorus, sulfur or oxygen, said moiety having up to 60
non-hydrogen atoms; p is 0, 1 or 2; q is zero or one; with the
proviso that: when p is 2, q is zero, M is in the +4 formal
oxidation state, and X is an anionic ligand selected from the group
consisting of halide, hydrocarbyl, hydrocarbyloxy,
di(hydrocarbyl)amido, di(hydrocarbyl)phosphido, hydrocarbylsulfido,
and silyl groups, as well as halo-, di(hydrocarbyl)amino-,
hydrocarbyloxy- and di(hydrocarbyl)phosphino-substituted
derivatives thereof, said X group having up to 20 non-hydrogen
atoms, when p is 1, q is zero, M is in the +3 formal oxidation
state, and X is a stabilizing anionic ligand group selected from
the group consisting of allyl, 2-(N,N-dimethylamino-methyl)phenyl,
and 2-(N,N-dimethyl)-aminobenzyl, or M is in the +4 formal
oxidation state, and X is a divalent derivative of a conjugated
diene, M and X together forming a metallocyclopentene group, and
when p is 0, q is 1, M is in the +2 formal oxidation state, and X'
is a neutral, conjugated or nonconjugated diene, optionally
substituted with one or more hydrocarbyl groups, said X' having up
to 40 carbon atoms and forming a .pi.-complex with M.
[0039] A most preferred coordination complex,
(t-butylamido)-dimethyl(.eta-
..sup.5-2-methyl-s-indacen-1-yl)silanetitanium (II) 1,3-pentadiene,
has two isomers, sometimes referred to as geometric isomers,
represented by Formulae IVA and IVB. 5
[0040] Specific examples of coordination complexes are detailed in
PCT/US 97/07252, previously incorporated by reference, at page 10,
line 3 through page 16, line 36. The coordination complex is
preferably selected from the group consisting of
(t-butylamido)dimethyl(.eta..sup.5-2-methyl--
s-indacen-1-yl)silanetitanium (II) 2,4-hexadiene,
(t-butylamido)-dimethyl
(.eta..sup.5-2-methyl-s-indacen-1-yl)silane-titanium (IV) dimethyl,
(t-butylamido)-dimethyl(5-2,3-dimethylindenyl)silanetitanium (II)
1,4-diphenyl-1,3-butadiene,
(t-butyl-amido)-dimethyl(.eta..sup.5-2,3-dime-
thyl-s-indacen-1-yl)silanetitanium (IV) dimethyl, and
(t-butylamido)-dimethyl
(.eta..sup.5-2-methyl-s-indacen-1-yl)silanetitani- um (II)
1,3-pentadiene. Preferred members of this group include:
(t-butylamido)-dimethyl(.eta..sup.5-2-methyl-s-indacen-1-yl)silane-titani-
um (IV) dimethyl, (t-butylamido)dimethyl
(.eta..sup.5-2-methylindenyl)-sil- anetitanium (II) 2,4-hexadiene
and (t-butylamido)-dimethyl(.eta..sup.5-2-m-
ethyl-s-indacen-1-yl)silanetitanium (II) 1,3-pentadiene. The most
preferred coordination complex is and (t-butylamido)-dimethyl
(.eta..sup.5-2-methyl-s-indacen-1-yl)silanetitanium (II)
1,3-pentadiene.
[0041] Other preferred metal complexes include derivatives of any
transition metal including Lanthanides, but preferably of Group 3,
4, or Lanthanide metals which are in the +2, +3, or +4 formal
oxidation state meeting the previously mentioned requirements.
Preferred compounds include metal complexes (metallocenes)
containing from 1 to 3 .pi.-bonded anionic ligand groups, which may
be cyclic or noncyclic delocalized .pi.-bonded anionic ligand
groups. Exemplary of such .pi.-bonded anionic ligand groups are
conjugated or nonconjugated, cyclic or non-cyclic dienyl groups,
allyl groups, and arene groups. Such other preferred metal
complexes correspond to the formula:
L.sub.1MX.sub.mX'.sub.nX".sub.p, or a dimer thereof, wherein: L is
an anionic, delocalized, .pi.-bonded group that is bound to M,
containing up to 50 atoms not counting hydrogen, optionally two L
groups may be joined together through one or more substituents
thereby forming a bridged structure, and further optionally one L
may be bound to X through one or more substituents of L; M is a
metal of Group 4 of the Periodic Table of the Elements in the +2,
+3 or +4 formal oxidation state; X is an optional, divalent
substituent of up to 50 non-hydrogen atoms that together with L
forms a metallocycle with M; X' is an optional neutral Lewis base
having up to 20 non-hydrogen atoms; X" each occurrence is a
monovalent, anionic moiety having up to 40 non-hydrogen atoms,
optionally, two X" groups may be covalently bound together forming
a divalent dianionic moiety having both valences bound to M, or
form a neutral, conjugated or nonconjugated diene that is
.pi.-bonded to M (whereupon M is in the +2 oxidation state), or
further optionally one or more X" and one or more X' groups may be
bonded together thereby forming a moiety that is both covalently
bound to M and coordinated thereto by means of Lewis base
functionality; 1 is 1 or 2; m is 0 or 1; n is a number from 0 to 3;
p is an integer from 0 to 3; and the sum, l+m+p, is equal to the
formal oxidation state of M. A variation of such complexes has each
occurrence of X" containing up to 20 non-hydrogen atoms, two X"
groups together forming a neutral C5-30 conjugated diene, m=1 and p
being 1 or 2.
[0042] Preferred divalent X substituents include groups containing
up to 30 atoms not counting hydrogen comprising at least one atom
that is oxygen, sulfur, boron or a member of Group 14 of the
Periodic Table of the Elements directly attached to the delocalized
.pi.-bonded group, and a different atom, selected from the group
consisting of nitrogen, phosphorus, oxygen or sulfur that is
covalently bonded to M.
[0043] Such other preferred complexes include those containing
either one or two L groups. The latter complexes include those
containing a bridging group linking the two L groups. Preferred
bridging groups are those corresponding to the formula
(ER*.sub.2).sub.x wherein E is silicon or carbon, R* independently
each occurrence is hydrogen or a group selected from silyl,
hydrocarbyl, hydrocarbyloxy and combinations thereof, said R*
having up to 30 carbon or silicon atoms, and x is 1 to 8.
Preferably, R* independently each occurrence is methyl, benzyl,
tert-butyl or phenyl.
[0044] Examples of the foregoing bis(L) containing complexes are
compounds corresponding to the formulae V and VI: 6
[0045] wherein: M is titanium, zirconium or hafnium, preferably
zirconium or hafnium, in the +2 or +4 formal oxidation state;
R.sup.3 in each occurrence independently is selected from the group
consisting of hydrogen, hydrocarbyl, dihydrocarbylamino,
hydrocarbyleneamino, silyl, germyl, cyano, halo and combinations
thereof, said R.sup.3 having up to 20 atoms not counting hydrogen,
or adjacent R.sup.3 groups together form a divalent derivative
thereby forming a fused ring system, and X" independently each
occurrence is an anionic ligand group of up to 40 atoms not
counting hydrogen, or two X" groups together form a divalent
anionic ligand group of up to 40 atoms not counting hydrogen or
together are a conjugated diene having from 4 to 30 atoms not
counting hydrogen forming a .pi.-complex with M, whereupon M is in
the +2 formal oxidation state, and R*, E and x are as previously
defined.
[0046] The foregoing metal complexes are especially suited for the
preparation of polymers having stereoregular molecular structure.
In such capacity it is preferred that the complex possess C.sub.2
symmetry or possess a chiral, stereorigid structure. Examples of
the first type are compounds possessing different delocalized
.pi.-bonded systems, such as one cyclopentadienyl group and one
fluorenyl group. Similar systems based on Ti(IV) or Zr(IV) were
disclosed for preparation of syndiotactic olefin polymers in Ewen,
et al., J. Am. Chem. Soc. 110, 6255-6256 (1980). Examples of chiral
structures include bis-indenyl complexes. Similar systems based on
Ti(IV) or Zr(IV) were disclosed for preparation of isotactic olefin
polymers in Wild et al., J. Organomet. Chem, 232, 233-47,
(1982).
[0047] Exemplary bridged ligands containing two .pi.-bonded groups
are: (dimethylsilyl-bis-cyclopentadienyl),
(dimethylsilyl-bis-methylcyclopenta- dienyl),
(dimethylsilyl-bis-ethylcyclopentadienyl, (dimethylsilyl-bis-t-bu-
tylcyclopentadienyl),
(dimethylsilyl-bis-tetramethylcyclopentadienyl),
(dimethylsilyl-bis-indenyl), (dimethylsilyl-bis-tetrahydroindenyl),
(dimethylsilyl-bis-fluorenyl),
(dimethylsilyl-bis-tetrahydrofluorenyl),
(dimethylsilyl-bis-2-methyl-4-phenylindenyl),
(dimethylsilyl-bis-2-methyl- indenyl),
(dimethylsilyl-cyclopentadienyl-fluorenyl),
(1,1,2,2-tetramethyl-1,2-disilyl-bis-cyclopentadienyl),
(1,2-bis(cyclopentadienyl)ethane, and
(isopropylidene-cyclopentadienyl-fl- uorenyl).
[0048] Preferred X" groups are selected from hydride, hydrocarbyl,
silyl, germyl, halohydrocarbyl, halosilyl, silylhydrocarbyl and
aminohydrocarbyl groups, or two X" groups together form a divalent
derivative of a conjugated diene or else together they form a
neutral, .pi.-bonded, conjugated diene.
[0049] Preferred constrained geometry metal complexes, also
referred to as Group 4 metal coordination complexes, that
correspond to Formula VII below may be found in previously
incorporated U.S. Pat. No. 5,470,993, U.S. Pat. No. 5,556,928 and
U.S. Pat. No. 5,624,878. See, e.g., U.S. Pat. No. 5,624,878 at
column 1, line 61 through column 3, line 42 and column 6, line 14
through column 7, line 46. 7
[0050] wherein: M is titanium or zirconium in the +2 or +4 formal
oxidation state; R.sup.3 in each occurrence independently is
selected from the group consisting of hydrogen, hydrocarbyl, silyl,
germyl, cyano, halo and combinations thereof, said R.sup.3 having
up to 20 non-hydrogen atoms, or adjacent R.sup.3 groups together
form a divalent derivative (that is, a hydrocarbadiyl, siladiyl or
germadiyl group) thereby forming a fused ring system; each X" is a
halo, hydrocarbyl, hydrocarbyloxy or silyl group, said group having
up to 20 atoms not counting hydrogen, or two X" groups together
form a C.sub.5-30 conjugated diene; Y is --O--, --S--, --NR*--,
--PR*--; and Z is SiR*.sub.2, CR*.sub.2, SiR*.sub.2SiR*.sub.2,
CR*.sub.2CR*.sub.2, CR*=CR*, CR*.sub.2SiR*.sub.2, or GeR*.sub.2,
wherein: R* is as previously defined.
[0051] The foregoing delocalized .pi.-bonding groups, metal
complexes containing the same and catalyst compositions based
thereon, are more fully disclosed in the following publications:
U.S. Pat. Nos. 5,703,187, 5,064,802, 5,321,106, 5,374,696,
5,470,993, 5,624,878, 5,556,928, 5,486,632, 5,541,349, 5,495,036,
5,527,929, 5,616,664, WO 97/15583, WO97/35864, WO98/06727, and
WO98/27103, the teachings of which, or of the corresponding
equivalent United States application, are incorporated herein by
reference.
[0052] Illustrative Group 4 metal complexes may be found in U.S.
Pat. No. 5,624,878 at column 9, line 9 through column 13, line 59.
Some of those complexes include the following:
(tert-butylamido)-(tetramethyl-.eta..sup- .5-cyclopentadienyl)
dimethylsilanetitanium dichloride,
(tert-butylamido)(tetramethyl-.eta..sup.5-cyclopentadienyl)dimethylsilane-
titanium dimethyl, (tert-butylamido)
(tetramethyl-.eta..sup.5-cyclopentadi- enyl)-1,2-ethanediyltitanium
dimethyl, (tert-butylamido)(hexamethyl-.eta..-
sup.5-indenyl)-dimethylsilanetitanium dimethyl,
(tert-butylamido)(tetramet-
hyl-.eta..sup.5-cyclopentadienyl)dimethylsilane titanium (III)
2-(dimethylamino)benzyl;
(tert-butylamido)(tetramethyl-.eta..sup.5-cyclop-
entadienyl)-dimethylsilanetitanium (III) allyl,
(tert-butylamido)(tetramet-
hyl-.eta..sup.5-cyclopentadienyl)-dimethyl-silanetitanium (II)
1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2-methylindenyl)dimethyl-si- lanetitanium (II)
1,4-diphenyl-1,3-butadiene, (tert-butylamido)(2-methylin-
denyl)dimethyl-silanetitanium (IV) 1,3-butadiene,
(tert-butylamido)(2,3-di- methylindenyl)dimethylsilanetitanium (II)
1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2,3-dimethylindenyl)dimethylsilanetitanium (IV)
1,3-butadiene,
(tert-butylamido)(2,3-dimethylindenyl)-dimethylsilanetitan- ium
(II) 1,3-pentadiene,
(tert-butylamido)(2-methylindenyl)dimethylsilanet- itanium (II)
1,3-pentadiene, (tert-butylamido)(2-methylindenyl)dimethylsil-
anetitanium (IV) dimethyl,
(tert-butylamido)(2-methyl-4-phenylindenyl)-dim-
ethylsilanetitanium (II) 1,4-diphenyl-1,3-butadiene,
(tert-butylamido)(2-methyl-4-phenylindenyl)-dimethylsilanetitanium
(II) 1,3-pentadiene, (tert-butylamido)
(tetramethyl-.eta..sup.5-cyclopentadien- yl)-dimethylsilanetitanium
(IV) 1,3-butadiene, (tert-butylamido)
(tetramethyl-.eta..sup.5-cyclopentadienyl)-dimethylsilanetitanium
(II) 1,4-dibenzyl-1,3-butadiene,
(tert-butylamido)-(tetramethyl-.eta..sup.5-cy-
clopentadienyl)dimethyl-silanetitanium (II) 2,4-hexadiene,
(tert-butylamido)(tetramethyl-.eta..sup.5-cyclopentadienyl)-dimethylsilan-
etitanium (II) 3-methyl-1,3-pentadiene,
(tert-butylamido)(2,4-dimethyl-1,3-
-pentadien-2-yl)dimethylsilanetitaniumdimethyl,
(tert-butylamido)(1,1-dime-
thyl-2,3,4,9,10-.eta.-1,4,5,6,7,8-hexahydronaphthalen-4-yl)dimethyl-silane-
titaniumdimethyl,
(tert-butylamido)(1,1,2,3-tetramethyl-2,3,4,9,10-.eta.-1-
,4,5,6,7,8-hexahydronaphthalen-4-yl)dimethylsilanetitaniumdimethyl,
(tert-butylamido)(tetramethyl-cyclopentadienyl)-dimethylsilanetitanium
1,3-pentadiene,
(tert-butylamido)(3-(N-pyrrolidinyl)inden-1-yl)dimethylsi-
lanetitanium 1,3-pentadiene,
(tert-butylamido)(2-methyl-s-indacen-1-yl)dim- ethylsilanetitanium
1,3-pentadiene, (tert-butylamido)(2-methyl-s-indacen-1-
-yl)dimethylsilanetitanium 1,4-diphenyl-1,3-butadiene, and
(tert-butylamido)(3,4-cyclopenta(1)phenanthren-2-yl)dimethylsilane-titani-
um 1,4-diphenyl-1,3-butadiene. The Group 4 metal complex is
preferably selected from
(t-butylamido)-(tetramethyl-.eta..sup.5-cyclopentadienyl)-d-
imethylsilanetitanium .eta..sup.4-3-methyl-1,3-pentadiene and
C.sub.5Me.sub.4SiMe.sub.2NtBu)Ti(.eta..sup.4-1,3-pentadiene).
[0053] Bis(L) containing complexes including bridged complexes
suitable for use in the present invention include:
biscyclopentadienylzirconiumdim- ethyl,
biscyclopentadienyl-titaniumdiethyl,
biscyclopentadienyltitaniumdii- sopropyl,
biscyclopentadienyltitanium-diphenyl, biscyclopenta-dienylzircon-
ium dibenzyl, biscyclopentadienyltitanium-2,4-pentadienyl,
biscyclopentadienyl-titaniummethylmethoxide,
biscyclopentadienyltitanium-- methylchloride,
bispentamethylcyclo-pentadienyltitaniumdimethyl,
bisindenyltitanium-dimethyl, indenylfluorenyltitaniumdiethyl,
bisindenyltitaniummethyl(2-(dimethylamino)-benzyl),
bisindenyltitanium methyltrimethylsilyl,
bistetrahydroindenyl-titanium methyltrimethylsilyl,
bispentamethylcyclopentadienyltitaniumdiisopropyl,
bispentamethylcyclopentadienyltitaniumdibenzyl,
bispentamethylcyclopentad- ienyl-titaniummethylmethoxide,
bispentamethylcyclopentadienyltitaniummethy- lchloride,
(dimethylsilyl-bis-cyclopentadienyl)zirconiumdimethyl,
(dimethylsilyl-bis-pentamethyl-cyclopentadienyl)titanium-2,4-pentadienyl,
(dimethylsilyl-bis-t-butylcyclopentadienyl)-zirconiumdichloride,
(methylene-bis-pentamethylcyclopentadienyl)titanium(III)
2-(dimethylamino)benzyl,
(dimethylsilyl-bis-indenyl)zirconiumdichloride,
(dimethylsilyl-bis-2-methylindenyl)zirconiumdimethyl,
(dimethylsilyl-bis-2-methyl-4-phenylindenyl)-zirconiumdimethyl,
(dimethylsilyl-bis-2-methylindenyl)-zirconium-1,4-diphenyl-1,3-butadiene,
(dimethylsilyl-bis-2-methyl-4-phenylindenyl)zirconium (II)
1,4-diphenyl-1,3-butadiene,
(dimethylsilyl-bis-tetrahydroindenyl)zirconiu- m(II)
1,4-diphenyl-1,3-butadiene,
(dimethylsilyl-bis-fluorenyl)zirconiumdi- chloride,
(dimethylsilyl-bis-tetrahydrofluorenyl)-zirconium-di(trimethylsi-
lyl),
(isopropylidene)(cyclopentadienyl)(fluorenyl)-zirconiumdibenzyl,
and
(dimethylsilylpentamethylcyclopentadienylfluorenyl)-zirconiumdimethyl.
[0054] The foregoing metal complexes can be prepared by use of well
known synthetic techniques. Optionally a reducing agent can be
employed to produce the lower oxidation state complexes. Such a
process is disclosed in U.S. Ser. No. 8/241,523, filed May 13,
1994, published as WO95-00526, the teachings of which are hereby
incorporated by reference, and in WO 98/27103 and PCT/US97/07252
(previously incorporated by reference). The syntheses are conducted
in a suitable non-interfering solvent at a temperature from -100 to
300.degree. C., preferably from -78 to 100.degree. C., most
preferably from 0 to 50.degree. C. By the term "reducing agent"
herein is meant a metal or compound which, under reducing
conditions causes the metal M, to be reduced from a higher to a
lower oxidation state. Examples of suitable metal reducing agents
are alkali metals, alkaline earth metals, aluminum and zinc, alloys
of alkali metals or alkaline earth metals such as sodium/mercury
amalgam and sodium/potassium alloy. Examples of suitable reducing
agent compounds are group 1 or 2 metal hydrocarbyl compounds having
from 1 to 20 carbons in each hydrocarbyl group, such as, sodium
naphthalenide, potassium graphite, lithium alkyls, lithium or
potassium alkadienyls; and Grignard reagents. Most preferred
reducing agents are the alkali metals or alkaline earth metals,
especially lithium and magnesium metal.
[0055] Suitable reaction media for the formation of the complexes
include aliphatic and aromatic hydrocarbons, ethers, and cyclic
ethers, particularly branched-chain hydrocarbons such as isobutane,
butane, pentane, hexane, heptane, octane, and mixtures thereof;
cyclic and alicyclic hydrocarbons such as cyclohexane,
cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures
thereof; aromatic and hydrocarbyl-substituted aromatic compounds
such as benzene, toluene, and xylene, C.sub.1-4 dialkyl ethers,
C.sub.1-4 dialkyl ether derivatives of (poly)alkylene glycols, and
tetrahydrofuran. Mixtures of the foregoing are also suitable.
[0056] Mixtures of catalyst complexes, coordination complexes or
both may be used in the process aspect of the present invention.
For example, a coordination complex described in WO 98/27103 and
PCT/US97/07252 may be used in combination with a catalyst complex
like that described in, for example, U.S. Pat. No. 5,470,993.
Similarly, a combination of two or more of the coordination
complexes that are disclosed in WO 98/27103 and PCT/US97/07252 or
two or more of the catalyst complexes disclosed in U.S. Pat. No.
5,470,993 also produces acceptable results.
[0057] The foregoing description of catalyst complexes is
illustrative, but non-limiting. It is believed that any catalyst
that promotes vinyl end group termination under polymerization
conditions together with subsequent reinsertion into a polymer
chain would be satisfactory so long as the resulting polymer has a
PRR of at least four.
[0058] The complexes, whether they are catalyst complexes,
coordination complexes or both, are rendered catalytically active
by combining them with an activating cocatalyst or by use of an
activating technique. Suitable activating cocatalysts for use
herein include polymeric or oligomeric alumoxanes, especially
methylalumoxane, triisobutyl aluminum modified methylalumoxane, or
isobutylalumoxane; neutral Lewis acids, such as C.sub.1-30
hydrocarbyl substituted Group 13 compounds, especially
tri(hydrocarbyl)aluminum- or tri(hydrocarbyl)boron compounds and
halogenated (including perhalogenated) derivatives thereof, having
from 1 to 10 carbon atoms in each hydrocarbyl or halogenated
hydrocarbyl group, more especially perfluorinated tri(aryl)boron
compounds, and most especially tris(pentafluorophenyl)borane
(hereinafter "FAB").
[0059] As an alternative, the complexes are rendered catalytically
active by combining them with non-polymeric, compatible,
non-coordinating, ion forming compounds (including the use of such
compounds under oxidizing conditions), especially the use of
ammonium-, phosphonium-, oxonium-, carbonium-, silylium- or
sulfonium-salts of compatible, non-coordinating anions, or
ferrocenium salts of compatible, non-coordinating anions; and
combinations of the foregoing activating cocatalysts and
techniques. The foregoing activating cocatalysts and activating
techniques have been previously taught with respect to different
metal complexes in the following references: EP-A-277,003, U.S.
Pat. No. 5,153,157, U.S. Pat. No. 5,064,802, EP-A-468,651
(equivalent to U.S. Ser. No. 07/547,718), EP-A-520,732 (equivalent
to U.S. Ser. No. 07/876,268), and EP-A-520,732 (equivalent to U.S.
Ser. No. 07/884,966 filed May 1, 1992), the teachings of which are
incorporated herein by reference.
[0060] Combinations of neutral Lewis acids, especially the
combination of a trialkyl aluminum compound having from 1 to 4
carbon atoms in each alkyl group and a halogenated
tri(hydrocarbyl)boron compound having from 1 to 20 carbon atoms in
each hydrocarbyl group, especially FAB, further combinations of
such neutral Lewis acid mixtures with a polymeric or oligomeric
alumoxane, and combinations of a single neutral Lewis acid,
especially FAB with a polymeric or oligomeric alumoxane are
especially desirable activating cocatalysts. Preferred molar ratios
of Group 4 metal complex:FAB:alumoxane are from 1:1:1 to 1:5:20,
more preferably from 1:1:1.5 to 1:5:10. The use of lower levels of
alumoxane in the process of the present invention allows for
production of EAODM polymers with high catalytic efficiencies using
less of the expensive alumoxane cocatalyst. Additionally, polymers
with lower levels of aluminum residue, and hence greater clarity,
are obtained.
[0061] A further suitable ion forming, activating cocatalyst
comprises a compound which is a salt of a silylium ion and a
non-coordinating, compatible anion represented by the formula:
R.sub.3Si(X').sub.q.sup.+A.s- up.- wherein: R is C.sub.1-10
hydrocarbyl, and X', q and A.sup.- are as previously defined.
[0062] Preferred silylium salt activating cocatalysts are
trimethylsilylium tetrakispentafluoro-phenylborate,
triethylsilylium tetrakispentafluorophenylborate and ether
substituted adducts thereof. Silylium salts have been previously
generically disclosed in J. Chem Soc. Chem. Comm., 1993, 383-384,
as well as Lambert, J. B., et al., Organometallics, 1994, 13,
2430-2443. The use of the above silylium salts as activating
cocatalysts for addition polymerization catalysts is disclosed in
U.S. Ser. No. 304,314, filed Sep. 12, 1994, published in equivalent
form as WO96/08519 on Mar. 21, 1996, the teachings of which are
herein incorporated by reference.
[0063] Certain complexes of alcohols, mercaptans, silanols, and
oximes with FAB are also effective catalyst activators and may be
used according to the present invention. Such cocatalysts are
disclosed in U.S. Pat. No. 5,296,433, the teachings of which are
herein incorporated by reference.
[0064] The technique of bulk electrolysis involves the
electrochemical oxidation of the metal complex under electrolysis
conditions in the presence of a supporting electrolyte comprising a
non-coordinating, inert anion. The technique is more fully
explained at column 15, line 47 through column 16, line 48 of
previously incorporated U.S. Pat. No. 5,624,878.
[0065] The molar ratio of catalyst/cocatalyst employed preferably
ranges from 1:10,000 to 100:1, more preferably from 1:5000 to 10:1,
most preferably from 1:1000 to 1:1. Alumoxane, when used by itself
as an activating cocatalyst, is employed in large quantity,
generally at least 100 times the quantity of metal complex on a
molar basis (calculated on moles of aluminum (Al)). FAB, when used
as an activating cocatalyst, is employed in a molar ratio to the
metal complex of form 0.5:1 to 10:1, more preferably from 1:1 to
6:1 most preferably from 1:1 to 5:1. The remaining activating
cocatalysts are generally employed in approximately equimolar
quantity with the metal complex.
[0066] In general, polymerization may be accomplished at conditions
well known in the art for Ziegler-Natta or Kaminsky-Sinn type
polymerization reactions, that is, temperatures from 0-250.degree.
C., preferably 30 to 200.degree. C. and pressures from atmospheric
to 10,000 atmospheres. See, e.g., Kaminsky, J. Poly. Sci., Vol. 23,
pp. 2151-64 (1985) reporting the use of a soluble
bis(cyclopentadienyl) zirconium dimethyl-alumoxane catalyst system
for solution polymerization of EP and EAODM elastomers. U.S. Pat.
No. 5,229,478 discloses a slurry polymerization process utilizing
similar bis(cyclopentadienyl) zirconium based catalyst systems.
[0067] Suspension, solution, slurry, gas phase, solid state powder
polymerization or other process condition may be employed if
desired. A support, especially silica, alumina, or a polymer
(especially poly(tetrafluoroethylene) or a polyolefin) may be
employed, and desirably is employed when the catalysts are used in
a gas phase polymerization process. The support is preferably
employed in an amount to provide a weight ratio of catalyst (based
on metal):support from 1:100,000 to 1:10, more preferably from
1:50,000 to 1:20, and most preferably from 1:10,000 to 1:30. In
most polymerization reactions, the molar ratio of
catalyst:polymerizable compounds employed is from 10-12:1 to
10.sup.-1:1, more preferably from 10.sup.-9:1 to 10.sup.-5:1. The
process used to prepare the EAODM interpolymers of the present
invention may be either a solution or slurry process, both of which
are previously known in the art.
[0068] Inert liquids are suitable solvents for polymerization.
Examples include straight and branched-chain hydrocarbons such as
isobutane, butane, pentane, hexane, heptane, octane, and mixtures
thereof; cyclic and alicyclic hydrocarbons such as cyclohexane,
cycloheptane, methylcyclohexane, methylcycloheptane, and mixtures
thereof; perfluorinated hydrocarbons such as perfluorinated
C.sub.4-10 alkanes; and aromatic and alkyl-substituted aromatic
compounds such as benzene, toluene, xylene, and ethylbenzene.
Suitable solvents also include liquid olefins that may act as
monomers or comonomers including butadiene, cyclopentene, 1-hexene,
1-hexane, 4-vinylcyclohexene, vinylcyclohexane, 3-methyl-1-pentene,
4-methyl-1-pentene, 1,4-hexadiene, 1-octene, 1-decene, styrene,
divinylbenzene, allylbenzene, and vinyltoluene (including all
isomers alone or in admixture). Mixtures of the foregoing are also
suitable. If desired, normally gaseous olefins can be converted to
liquids by application of pressure and used herein.
[0069] The catalysts may be utilized in combination with at least
one additional homogeneous or heterogeneous polymerization catalyst
in separate reactors connected in series or in parallel to prepare
polymer blends having desirable properties. An example of such a
process is disclosed in WO 94/00500, equivalent to U.S. Ser. No.
07/904,770, as well as U.S. Ser. No. 08/10958, filed Jan. 29, 1993,
the teachings of which are incorporated herein by reference.
[0070] By using the foregoing catalysts, catalyst complexes and
coordination complexes in combination with cocatalysts in the
process of one aspect of the present invention, the interpolymers
of another aspect of the present invention are readily prepared.
The resulting EAO(D)M interpolymers exhibit a PRR of at least 4
without incorporating NBD or another conventional LCB monomer. The
interpolymers exhibit improved polymer processibility (which can
include a higher throughput rate), higher melt strength, higher
green strength, reduced die swell, resistance to melt fracture and
extendibility with fillers relative to interpolymers that have a
linear polymer backbone, but no LCB.
[0071] The catalysts used in the process of the present invention
are particularly advantageous for the production of interpolymers
that have a PRR of at least 4. The use of the catalysts in
continuous polymerization processes, especially continuous solution
polymerization processes, allows for elevated reactor temperatures
that favor the formation of vinyl terminated polymer chains that
may be incorporated into a growing polymer, thereby giving a long
chain branch. It is believed that the unique combination of
elevated reactor temperatures, high ethylene conversion and either
the substantial absence or very low levels of molecular hydrogen
yield the desired interpolymers of the first aspect of the
invention. "Very low levels", as used herein, means a level of more
than zero, but less than or equal to 0.1, mole percent, based upon
fresh ethylene feed content plus fresh hydrogen feed content.
[0072] In general terms, it is desirable to produce EAODM
elastomers under conditions of increased reactivity of the diene
monomer component. The reason for this was explained in the above
identified '478 patent in the following manner, which still remains
true despite the advances attained in such reference. A major
factor affecting production costs and hence the utility of an EAODM
is diene monomer cost. The diene is a more expensive monomer
material than C.sub.2 or C.sub.3. Further, the reactivity of diene
monomers with previously known metallocene catalysts is lower than
that of C.sub.2 and C.sub.3. Consequently, to achieve the requisite
degree of diene incorporation to produce an EAODM with an
acceptably fast cure rate, it has been necessary to use a diene
monomer concentration which, expressed as a percentage of the total
concentration of monomers present, is in substantial excess
compared to the percentage of diene desired to be incorporated into
the final EAODM product. Since substantial amounts of unreacted
diene monomer must be recovered from the polymerization reactor
effluent for recycle the cost of production is increased
unnecessarily.
[0073] Further adding to the cost of producing an EAODM is the fact
that, generally, the exposure of an olefin polymerization catalyst
to a diene, especially the high concentrations of diene monomer
required to produce the requisite level of diene incorporation in
the final EAODM product, often reduces the rate or activity at
which the catalyst will cause polymerization of ethylene and
propylene monomers to proceed. Correspondingly, lower throughputs
and longer reaction times have been required, compared to the
production of an ethylene-propylene copolymer elastomer or other
.alpha.-olefin copolymer elastomer.
[0074] The EAO(D)M polymers of the present invention may, as noted
above, also be prepared by gas phase polymerization, another well
known process wherein reactor cooling typically occurs via
evaporative cooling of a volatile material such as a recycle gas,
an inert liquid or a monomer or optional diene that is used to
prepare the EAO(D)M polymer. A suitable inert liquid is a
C.sub.3-8, preferably a C.sub.4-6, saturated hydrocarbon monomer.
The volatile material or liquid evaporates in the hot fluidized bed
to form a gas that mixes with the fluidizing gas. This type of
process is described, for example in EP 89691; U.S. Pat. No.
4,543,399; WO 94/25495; WO 94/28032; and U.S. Pat. No. 5,352,749,
the teachings of which are hereby incorporated by reference. Other
relevant teachings, also incorporated by reference, are found in
U.S. Pat. No. 4,588,790; U.S. Pat. No. 4,543,399; U.S. Pat. No.
5,352,749; U.S. Pat. No. 5,436,304; U.S. Pat. No. 5,405,922; U.S.
Pat. No. 5,462,999; U.S. Pat. No. 5,461,123; U.S. Pat. No.
5,453,471; U.S. Pat. No. 5,032,562; U.S. Pat. No. 5,028,670; U.S.
Pat. No. 5,473,028; U.S. Pat. No. 5,106,804; U.S. Pat. No.
5,541,270; EP-A-659,773; EP-A-692,500; and PCT Applications WO
94/29032, WO 94/25497, WO 94/25495, WO 94/28032; WO 95/13305; WO
94/26793; and WO 95/07942.
[0075] The polymerization reaction occurring in the gas fluidized
bed is catalyzed by the continuous or semi-continuous addition of
catalyst. Such catalyst can be supported on an inorganic or organic
support material.
[0076] The gas phase processes suitable for the practice of this
invention are preferably continuous processes that provide for a
continuous supply of reactants to the reaction zone of the reactor
and the removal of products from the reaction zone of the reactor,
thereby providing a steady-state environment on the macro scale in
the reaction zone of the reactor.
[0077] In contrast, solution polymerization conditions use a
solvent for the respective components of the reaction. Preferred
solvents include mineral oils and the various hydrocarbons that are
liquid at reaction temperatures. Illustrative examples of useful
solvents include alkanes such as pentane, iso-pentane, hexane,
heptane, octane and nonane, as well as mixtures of alkanes
including kerosene and Isopar E.TM., available from Exxon Chemicals
Inc.; cycloalkanes such as cyclopentane and cyclohexane; and
aromatics such as benzene, toluene, xylenes, ethylbenzene and
diethylbenzene.
[0078] At all times, the individual ingredients as well as the
recovered catalyst components should be protected from oxygen and
moisture. Therefore, the catalyst components and catalysts should
be, and preferably are, prepared and recovered in an oxygen and
moisture free atmosphere. Preferably, therefore, the reactions are
performed in the presence of an dry, inert gas such as, for
example, nitrogen.
[0079] Ethylene is added to a reaction vessel in an amount
sufficient to maintain a differential pressure in excess of the
combined vapor pressure of the .alpha.-olefin and diene monomers.
The C.sub.2 content of the polymer is determined by the ratio of
C.sub.2 differential pressure to the total reactor pressure.
Generally, polymerization occurs with a differential pressure of
C.sub.2 of from 10 to 1500 pounds per square inch (psi) (70 to
10500 kPa), most preferably from 40 to 800 psi (280 to 5600 kPa).
The polymerization temperature is suitably from 70 to 225.degree.
C., preferably from 80 to 170.degree. C., and most preferably from
greater than 80 to 140.degree. C.
[0080] The polymerization reaction is desirably conducted under
conditions sufficient to attain an ethylene conversion of at least
60 wt %, based upon amount of ethylene fed to a reactor. The
ethylene conversion is preferably above 65 wt %, more preferably
above 70 wt %. The polymer concentration in the reactors under
steady state conditions solution process is desirably from 5 to 25
wt %, preferably from 8 to 25 wt % and most preferably from 10 to
20 wt %. Solution process polymer concentrations in excess of 25 wt
% may be used provided the resulting polymer solution has a
solution viscosity that favors further processing. Processes other
than a solution process, such as slurry or gas phase processes,
have different, but readily determined, polymer concentration
limits.
[0081] Polymerization may occur in either a batch or a continuous
polymerization process using one or more reactors. Polymerization
preferably occurs via a continuous process so that catalyst,
ethylene, .alpha.-olefin, diene and optional solvent are
continuously supplied to the reaction zone and polymer product
continuously removed therefrom.
[0082] Without limiting in any way the scope of the invention, one
means for carrying out such a polymerization process uses a
stirred-tank reactor into which .alpha.-olefin monomer is
introduced continuously together with solvent, diene monomer and
C.sub.2 monomer. The reactor contains a liquid phase composed
substantially of C.sub.2, C.sub.3 and diene (also known as
"polyene") monomers together with any solvent or additional
diluent. If desired, a small amount of a traditional LCB inducing
diene such as NBD, 1,7-octadiene or 1,9-decadiene may also be added
so long as it does not adversely affect desirable polymer
properties. Catalyst and co-catalyst are continuously introduced in
the reactor liquid phase. The reactor temperature and pressure may
be controlled by adjusting the solvent/monomer ratio, the catalyst
addition rate, and by use of cooling or heating coils, jackets or
both. The rate of catalyst addition controls the polymerization
rate. Manipulating the respective feed rates of ethylene,
.alpha.-olefin and diene to the reactor provides control over
ethylene content of the polymer product. Polymer product molecular
weight control follows from controlling other polymerization
variables such as the temperature, monomer concentration, or
introducing a stream of hydrogen into the reactor. The reactor
effluent is contacted with a catalyst kill agent such as water. The
polymer solution is optionally heated, and the polymer product is
recovered by flashing off gaseous ethylene and propylene as well as
residual diene and residual solvent or diluent at reduced pressure,
and, if necessary, conducting further devolatilization in equipment
such as a devolatilizing extruder. In a continuous process, the
mean residence time of the catalyst and polymer in the reactor
generally is from 5 minutes to 8 hours, and preferably from 10
minutes to 6 hours.
[0083] In a preferred manner of operation, the polymerization is
conducted in a continuous solution polymerization system comprising
two reactors connected in series or parallel. In one reactor, a
relatively high molecular weight product (M.sub.w from 50,000 to
1,000,000, more preferably from 100,000 to 500,000) is formed in
the absence of hydrogen while, in the second reactor, a product of
a relatively low molecular weight (M.sub.w 20,000 to 300,000) is
formed. The presence of hydrogen in the second reactor is optional.
As an alternative, the same molecular weight product can be
produced in each of the two reactors. The final product is a blend
of the two reactor effluents that are combined prior to
devolatilization to result in a uniform blend of the two polymer
products. Such a dual reactor process allows for the preparation of
products having improved properties. In a preferred embodiment, the
reactors are connected in series, that is effluent from the first
reactor is charged to the second reactor and fresh monomer, solvent
and hydrogen are added to the second reactor. Reactor conditions
are adjusted such that the weight ratio of polymer produced in the
first reactor to that produced in the second reactor is from 20:80
to 80:20. If desired, however, a broader range of weight ratios may
be used. If desired also a use of different catalyst systems for
each reactor may be employed. For example, a metallocene based
catalyst system utilizing process conditions outlined earlier in
one reactor and a conventional Ziegler-Natta or another type of
metallocene based catalyst system in the second reactor which may
or may utilize the outlined process conditions. In addition, the
temperature of the second reactor is controlled to produce the
lower M.sub.w product. This system beneficially allows for
production of EAODM products having a large MV range, as well as
excellent strength and processibility. Although this preferred
manner of operation employs two reactors, three or more reactors
may also be used.
EXAMPLES
[0084] The following examples illustrate but do not, either
explicitly or by implication, limit the present invention. Unless
otherwise stated, all parts and percentages are expressed on a
weight basis.
[0085] Physical property evaluation of EAODM polymers uses a number
of standard tests. The tests include MV, compositional analysis via
Fourier transform infrared analysis (FTIR) (ASTM D3900), and
density (ASTM D-792). Other definitive properties include rheology
ratio, determined as described below, and PRR, determined as
described above
[0086] RR (V.sub.0.1/V.sub.100) is determined by examining samples
using melt rheology techniques on a Rheometric Scientific, Inc.
ARES (Advanced Rheometric Expansion System) dynamic mechanical
spectrometer (DMS). The samples are examined at 190.degree. C.
using the dynamic frequency mode and 25 millimeter (mm) diameter
parallel plate fixtures with a 2 mm gap. With a strain rate of 8%
and an oscillatory rate that is incrementally increased from 0.1 to
100 rad/sec, 5 data points taken for each decade of frequency
analyzed. Each sample (either pellets or bale) is compression
molded into 3 inch (1.18 centimeter (cm)) plaques 1/8 inch (0.049
cm) thick at 20,000 psi (137.9 megapascals (MPa)) pressure for 1
minute at 180.degree. C. The plaques are quenched and cooled (over
a period of 1 minute) to room temperature. A 25 mm plaque is cut
from the center portion of the larger plaque. These 25 mm diameter
aliquots are then inserted into the ARES at 190.degree. C. and
allowed to equilibrate for 5 minutes prior to initiation of
testing. The samples are maintained in a nitrogen environment
throughout the analyses to minimize oxidative degradation. Data
reduction and manipulation are accomplished by the ARES2/A5:RSI
Orchestrator Windows 95 based software package. RR measures the
ratio of the viscosity versus shear rate curve.
[0087] Interpolymer MV (ML.sub.1+4 at 125.degree. C.) is measured
in accordance with American Society for Testing and Materials test
D1646-94 (ASTM D1646-94). The PRR is calculated from the MV and the
RR in accordance with the formula provided above.
[0088] Polymer MWD is determined by gel permeation chromatography
(GPC) using a Millipore/Waters 150-C ALC/GPC chromatograph. A 0.10
milligram (mg) interpolymer sample is added to 50.0 milliliter (ml)
of 1,2,4-trichlorobenzene and heated at 160.degree. C. for 2 hours.
After this, a 5 ml aliquot is dispensed into a 1 dram (0.37
centiliter) autosampler vial and loaded into the instrument sample
chamber via a 16 position carousel. After equilibrating for 90
minutes at 130.degree. C. within the chromatograph, a 100
microliter sample aliquot is injected onto the Polymer Labs
PLgel.RTM. 10 micrometer Mixed-B 900.times.7.5 millimeter GPC
column under conditions sufficient to provide an elution time of 60
minutes at a flow rate of 1 ml per minute. A Millipore/Waters
Differential Refractive Index detector is used to measure the
concentration response of the effluent. TriSec v2.7 software is
used to effect data acquisition, reduction and manipulation with
calibration based on NBS traceable Polystyrene standards.
[0089] Catalyst efficiency (Cat. Eff.) is specified in terms of
million pounds of polymer per pound of Group IV metal in the
catalyst (MM#/#). For the batch process, it is determined by
weighing the polymer product and dividing by the amount of Group IV
metal added to the reactor. For a continuous process, polymer
product weight is determined by measured ethylene or vent
conversion.
Example 1-3
[0090] Three sample ethylene/propylene/ENB interpolymer
compositions, all representing the present invention, are prepared
using a single loop reactor that is designed for the continuous
addition of reactants and continuous removal of polymer solution.
Devolatilization and polymer recovery follow removal of polymer
solution from the reactor. The catalyst, cocatalyst and scavenger
for the Examples 1 and 2 are, respectively, (t-butylamido)-dimethyl
(.eta..sup.5-2-methyl-s-indacen-1-y- l)silanetitanium(II)
1,3-pentadiene, FAB and MMAO (triisobutyl aluminum modified
methylalumoxane). See Example 3 of PCT/US97/07252 (previously
incorporated by reference) for details about preparation of this
catalyst. The catalyst for Example 3 is
(tetramethylcyclo-pentadienyl)dim- ethyl
(t-butylamido)-silanetitanium 1,3-pentadiene. Example 1 uses a
reactor temperature of 120.degree. C. and an ethylene conversion of
92.3% to obtain an interpolymer product. Example 2 uses a reactor
temperature of 126.degree. C. and an ethylene conversion of 86.1%
to obtain an interpolymer product. Neither Example employs a flow
of gaseous hydrogen (H.sub.2). Examples 1 and 2 both use a pressure
of 473 pounds per square inch gauge (psig) (3.26 megapascals
(MPa)). Example 3 has a H2 flow rate of 10 standard cubic
centimeters per minute (sccm) and uses a pressure of 795 psig (5.5
MPa) and a reactor temperature of 101.degree. C.
[0091] The interpolymers are prepared using the procedure outlined
in Example 4 of PCT/US97/07252 (previously incorporated by
reference) as modified for Example 3 only to reflect the absence of
hydrogen. As such, ethylene and propylene are combined into one
stream before being introduced into a diluent mixture that
comprises a mixed alkane solvent (Isopar-E.TM., available from
Exxon Chemicals Inc.) and ENB to form a combined feed mixture. The
combined feed mixture is continuously injected into the reactor.
The catalyst and a blend of the cocatalyst and scavenging compound
are combined into a single stream that is also continuously
injected into the reactor.
[0092] Table IA shows flow rates for solvent, C.sub.2, propylene
(C.sub.3) and ENB in pounds per hour (pph). Table IA also shows
concentrations of catalyst (Cat) in parts per million (ppm)
cocatalyst (Cocat) in ppm and scavenger (Scav) in ppm flow rates,
in pph, for Cat, Cocat (FAB) and Scav (MMAO). Table IB shows
catalyst efficiency, a ratio of cocat to metal (M), where M is
titanium (Ti), a ratio of scavenger:titanium (Scav/Ti) and polymer
properties (MV and EAODM composition (as determined by FTIR)), RR,
PRR, M.sub.w and MWD. The C.sub.2 conversions for Examples 1-3 are,
respectively, 92.3 wt %, 86.1 wt % and 83 wt %.
[0093] A reactor exit stream is continuously introduced into a
separator, where molten polymer is continuously separated from the
unreacted comonomer, unreacted ethylene, unreacted ENB, and
solvent. An underwater pelletizer converts molten polymer into
solid pellets.
1TABLE IA Solvent C.sub.2 C.sub.3 ENB Cat Cocat Scav Cat Cocat
Scavenger Ex Flow Flow Flow Flow Conc Conc Conc flow flow flow No
(pph) (pph) (pph) (pph) (pph) (pph) (pph) (pph) (pph) (pph) 1 244
32.1 15 0.16 0.54 23.2 1.52 0.76 0.81 0.53 2 235 34.5 17.7 0.25
0.39 16.4 1.07 0.5 0.52 0.16 3 67,800 8610 4230 104 1.0 6.2 0.6
27.3 16.1 21.5
[0094]
2TABLE IB Cat Scav/ Ex Eff FAB/Ti Ti C.sub.3 ENB No (MM#/#) Ratio
Ratio RR PRR MV (wt %) (wt %) MW (M.sub.w) MWD 1 0.314 3.99 4.98 41
34.7 24.8 28.7 0.44 100,100 2.53 2 0.454 4.97 4.97 30 23.2 26.5
28.8 0.43 113,000 2.3 3 1.1 5 3 48.1 35.8 44.7 30 0.68 152,800
2.3
[0095] The data presented in Examples 1-3 illustrate several
points. First, a polymer with an acceptable PRR can be produced
either in the substantial absence of hydrogen (Examples 1 and 2) or
in the presence of very small amounts of hydrogen (Example 3).
Second, satisfactory PRR values can be obtained at varying
interpolymer MWs. Third, as shown in Examples 1 and 2, ethylene
conversion percentage affects interpolymer PRR, with higher
conversion (Example 1) yielding a higher PRR. It is believed that
conditions that minimize vinyl end group formation (also known as
"vinyl termination"), such as lower polymerization temperatures
(less than 70.degree. C.), higher levels of hydrogen (greater than
0.1 mole %), or both lead to an interpolymer PRR of less than
4.
Example 4
[0096] An EPDM interpolymer is prepared using a dual reactor (a
first reactor connected to a second reactor in series)
configuration rather than the single reactor of Examples 1-3. Each
reactor is designed and configured in the same manner as the single
reactor except that polymer recovery follows the second reactor.
Polymer preparation in the first reactor follows the procedure used
for the single reactor with different parameters, but without
polymer recovery. As in Examples 1 and 2, there is no hydrogen flow
in the first reactor. The parameters are as follows: C.sub.2 feed
rate of 22.9 pph, C.sub.3 feed rate of 9.3 pph, ENB feed rate of
0.08 pph, reactor temperature of 114.degree. C., catalyst flow rate
of 0.57 pph, cocatalyst (cocat or FAB) flow rate of 0.72 pph,
scavenger (scav or MMAO) flow rate of 0.56 pph, FAB/Ti (cocat/Ti)
ratio of 3.98, Scav/Ti ratio of 3.98 and C.sub.2 conversion of
92.9%. The catalyst efficiency is 0.295 MM#/#. The reactor pressure
is 475 psig (3.28 MPa).
[0097] Product from the first reactor enters the second reactor
where it encounters a new set of parameters that includes a flow of
gaseous hydrogen (H.sub.2). The parameters are as follows: C.sub.2
feed rate of 8.2 pph, C.sub.3 feed rate of 3.9 pph, ENB feed rate
of 0.03 pph, H.sub.2 feed rate of 364 sccm (0.018 mole % H.sub.21
based on moles of fresh H.sub.2 in the feed divided by moles of
fresh H.sub.2 in the feed plus moles of fresh C.sub.2 in the feed),
reactor temperature of 110.degree. C., catalyst flow rate of 0.41
pph, FAB flow rate of 0.51 pph, MMAO flow rate of 0.48 pph,
cocat/Ti ratio of 3.77, Scav/Ti ratio of 4.94 and C.sub.2
conversion of 82.6%. The reactor pressure is the same as in the
first reactor. The catalyst efficiency is 0.315 MM#/#. The
resulting polymer has a propylene content of 28.1% and an ENB
content of 0.55%, both percentages being based on resulting polymer
weight, an overall MV of 22.9, an overall M.sub.w of 109,100, an
overall MWD of 2.85, a RR of 42 and a PRR of 36.3. A sample of the
polymer solution from the first reactor, upon analysis, shows a PRR
of 76 and a MV, extrapolated from M.sub.w, of 40.
[0098] The reactor split between the first and second reactor is
59:41, meaning that 59% of the interpolymer is made in the first
reactor). As first conditions in the first reactor favor LCB
formation, 59% of the interpolymer contains LCB.
[0099] Example 4, like Examples 1-3, illustrates several points.
First, interpolymers of the present invention can be made in a dual
reactor configuration, even when conditions favoring a PRR of four
or more are present in only one of the two reactors. Skilled
artisans recognize, however, that attaining a product from the
second reactor with a PRR of at least four necessarily requires
that the polymer produced in the first reactor have a
correspondingly higher PRR. Second, a broadened MWD, due to a dual
reactor configuration, has no adverse impact upon interpolymer
PRR.
Example 5 and Comparative Example A
[0100] Example 4 is replicated using the conditions shown in Table
IIA-IID.
3 TABLE IIA C.sub.2 Feed C.sub.3 Feed ENB Feed H.sub.2 Flow Reactor
(pph) (pph) (pph) (sccm) Temp (.degree. C.) Ex Reactor ID 1 2 1 2 1
2 1 2 1 2 5 4286 4004 6397 5877 63.1 50.7 3 8 84 86 A 6449 6270
9457 8297 93.6 82 20 23 79.6 81.7
[0101]
4 TABLE IIB C.sub.2 Reactor Con- Pressure Cat Flow Cocat Flow Scav
Flow version (psig/ (pph) (pph) (pph) (wt %) MPa) Ex Reactor ID 1 2
1 2 1 2 1 2 1 2 5 32.4 25.6 16.1 12.7 18.7 14.9 67 55 801/ 852/
5.52 5.87 A 50 79.3 45 37 50 59 74 64 737/ 745/ 5.08 5.14
[0102]
5 TABLE IIC Cat Eff Cocat/ Scav/Ti Reactor % H.sub.2 (Mole %)
(MM#/#) Ti Ratio Ratio Polymer Reactor Ex ID 1 2 1 2 1 2 1 2 1 2 5
0.01 0.031 0.63 0.7 4 4 3.5 3.5 10 9.6 A 0.051 0.062 0.85 0.58 5 5
12 8.4 12.8 13.2
[0103]
6TABLE IID Overall C.sub.3 ENB Ex ID MV RR PRR (wt %) (wt %)
M.sub.w MWD 5 30 19.19 11.3 57.3 0.4 125,900 2.2 A 29 11.17 3.6
57.3 0.55 129,600 2.34
[0104] A comparison of Example 5 with Comparative Example A
illustrates the effect of varying levels of hydrogen. Excess
hydrogen, as in Comparative Example A, leads to a PRR of less than
4.
Example 6 and Comparative Example B
[0105] A standard wire and cable composition that comprises 100 pbw
of EAODM interpolymer, 8 pbw of low density polyethylene (LDPE) (2
dg/min melt index, 0.92 grams per cubic centimeter density, LD-400,
Exxon Chemical), 60 pbw of treated clay (vinyl silane-treated
aluminum silicate. (calcined), Translink.RTM. 37, Engelhard), 5 pbw
zinc oxide (85% zinc oxide in an EPDM binder, ZnO-85-SG,
Rhein-Chemie), 5 pbw lead stabilizer (90% red lead oxide in an EPDM
binder, TRD-90, Rhein-Chemie), 5 pbw paraffin wax (melt point of
130-135.degree. F. (54-57.degree. C.) International_Waxes, Ltd.), 1
pbw antioxidant (polymerized 1,2-dihydro-2,2,4-trimethyl quinoline,
Agerite.RTM. Resin D, R. T. Vanderbilt), 1 pbw coupling agent (40%
vinyl-tris-(2-methoxy-ethoxy)silan- e in a wax binder, PAC-473, OSI
Specialties) and 3.5 pbw dicumyl peroxide (DiCUP R.RTM., Hercules)
is process using a Davis-Standard extruder. For Example 6, the
polymer is prepared in the same manner as in Example 4 above, but
with a MV of 18 rather than 22. For comparative_Example B, the
polymer is Nordel.RTM. 2722, an
ethylene/propylene/1,4-hexadiene/NBD tetrapolymer commercially
available from DuPont Dow Elastomers L.L.C. The extruder is a 3.5
inch (8.9 centimeter (cm)) extruder equipped with a barrier screw
and mixing tip and having a length to diameter (L/D) ratio of 20:1.
The extruder tubing die has an outer diameter of 52.6 millimeters
(mm), an inner diameter of 0.375 inch (9.5 mm) and a length of 0.66
inch (16.8 mm). The extruder has a feed zone, three sequential
mixing zones, a die head zone and a die zone operating at
respective set temperatures of 190.degree. Farenheit (.degree. F.)
(88.degree. C.), 190.degree. F. (88.degree. C.), 200.degree. F.
(93.degree. C.), 200.degree. F. (93.degree. C.), 225.degree. F.
(107.degree. C.), and 225.degree. F. (107.degree. C.). The
extruder_is cooled with cooling water that has a temperature of
160.degree. F. (71.degree. C.). Table III below shows extruder
operating parameters and extrudate properties for Example 6 and
Comparative Example B.
7TABLE III Extruder Ex/ Extruder Output Extruder Melt Extrudate
Comp Speed (lbs/hr// Pressure Temp % Circumference % Die Ex (RPM)
kg/hr) (psi/MPa) (.degree. F./.degree. C.) Load (mm) Swell B 20
212/96.2 2145/14.8 248/120 40 75 42 B 30 316/143.3 2257/15.6
265/129 44 78 48 B 40 423/191.9 2300/15.9 271/133 47 78 48 6 20
214/97.1/ 1961/13.5 246/119 35 75 42 6 30 323/146.5 2088/14.4
265/129 40 79 50 6 40 418/189.6 2176/15.0 279/137 43 77 46
[0106] The data in Table III show that EPDM interpolymers of the
present invention, which do not contain a conventional LCB monomer,
provide extrudate properties that are comparable to those of
conventional tetrapolymers that do contain a conventional LCB
monomer. The data also show that the EPDM interpolymers of the
present invention process through the extruder at similar
throughput rates, but at lower pressures, than the
tetrapolymers.
Example 7
Thermoplastic Elastomer Preparation
[0107] A TPE is prepared by combining 63% PP (AccPro.RTM. 9934,
Amoco Chemical), 27% of an interpolymer prepared as in Example 4,
and 10% of a one micrometer talc (Microtuf.RTM. AG 101, Specialty
Minerals). The interpolymer has a MV of 18, a RR of 29.3 and a PRR
of 24.96. The interpolymer is expected to have a MWD of 2.8, based
on the other properties. The combination occurs in a 30 mm Werner
Pfleiderer twin screw extruder operating at a speed of 200
revolutions per minute (rpm) and a set temperature of 220.degree.
C. and produces an extrudate with a temperature of 225.degree. C.
The resulting extrudate is molded on a 100 ton (800 kiloNewton)
Arburg molding machine using a mold temperature of 83.degree. F.
(28.degree. C.) to provide test plaques. Physical property testing
of the test plaques yields a variety of data. The samples have a
Shore D hardness (ASTM D-2240) at 1 and 10 seconds of,
respectively, 62.2 and 58.9. The test plaques yield the following
tensile (ASTM D-638) properties when tested at a pull rate of two
inches (in) (5.1 cm) per minute: tensile at break of 2599 psi (17.9
MPa); ultimate elongation of 44%; a tensile at yield of 3064 psi
(21.1 MPa); and an elongation at yield of 6%. Weld line tensile
properties (ASTM D-638, two in/5.1 cm per minute pull rate) are:
tensile at break of 1877 psi (12.9 MPa); ultimate elongation of 2%;
tensile at yield of 1877 psi (12.9 MPa); and an elongation at yield
of 2%. The plaques provide a melt index (12) (ASTM D-1238,
230.degree. C., 2.16 kg) of 11.49 decigrams per minute (dg/min).
When subjected to a three-point flex test (ASTM D-790), testing
reveals a flex modulus of 219,273.5 psi (1511.9 MPa) and a 2%
secant modulus of 158,680.9 psi (1094.1 MPa). Gloss testing (ASTM
D-523) results at angles of incidence of 20.degree., 60.degree. and
85.degree. are, respectively 26.1, 55.0 and 96.9. Dynatup total
energy testing at 23.degree. C. yields a rating of 15.3 foot-pounds
(ft-lbs) (20.74 Joules (J)) Izod impact strength test results at
23.degree. C. and -30.degree. C. are, respectively, 0.97 ft-lbs/in
and 0.70 ft-lbs/in. Room temperature weldline Izod impact strength
is 1.43 ft-lbs/in. (3.0 KJSM (Kilo Joules Square Meters)). The heat
distortion at 66 psi (0.46 MPa) is 94.3.degree. C.
Example 8
TPO Preparation
[0108] Example 7 is replicated save for using an EO copolymer
prepared in a single reactor in place of the interpolymer used in
Example 7. The EO copolymer has a MV of 21, a RR of 16 and a PRR of
10.7. The resulting samples have a Shore D hardness at 1 and 10
seconds of, respectively, 65.4 and 61.6. The tensile properties are
tensile at break of 2342 psi (16.1 MPa); ultimate elongation of
146%; a tensile at yield of 3309 psi (22.8 MPa); and an elongation
at yield of 8%. Weld line tensile properties are tensile at break
of 1983 psi (13.7 MPa); ultimate elongation of 2%; tensile at yield
of 1978 psi (13.6 MPa); and an elongation at yield of 2%. The
plaques provide an 12 of 11.49 dg/min. The flex modulus and 2%
secant modulus are, respectively, 209,944.0 psi (1447.5 MPa) and
167,938.0 psi (1157.9 MPa). Gloss testing results at angles of
incidence of 20.degree., 60.degree. and 85.degree. are,
respectively 51.5, 71.5 and 91.2. Dynatup testing at 23.degree. C.
yields a rating of 20.5 ft-lbs (27.8 J) Izod impact strength
testing at 23.degree. C. yields a rating of 2.39 ft-lbs/in (5.0
KJSM). Room temperature weldline Izod impact strength is 1.82
ft-lbs/in. (3.8 KJSM).
[0109] Examples 7 and 8 show, respectively, that satisfactory TPEs
and TPOs can be prepared using interpolymers of the present
invention. Other TPEs, TPOs and TPVs, are suitably prepared
consistent with the teachings provided herein.
Example 9
EAO Polymer Preparation
[0110] The procedure of Examples 1 and 2 is replicated, save for
adding a flow of H.sub.2 and changing sparameter and monomers, to
produce an EO copolymer. The parameters are as follows: C.sub.2
feed rate of 30.4 pph, C.sub.8 feed rate of 29.8 pph, H.sub.2 feed
rate of 10.6 sccm (0.0055 mole %), reactor temperature of
102.degree. C., primary catalyst flow of 0.65 pph, co-cat flow of
0.35 pph, scav flow of 0.69 pph, C.sub.2 conversion of 89.8%,
reactor pressure of 475 psig (3.28 MPa), catalyst efficiency of
0.78 MM#/#, cocat/Ti molar ratio of 4, and a scav/Ti molar ratio of
5.54. The resulting polymer has a MV of 21.4, RR of 16, PRR of
10.7, MW of 120,300 and MWD of 2.6
[0111] Results similar to those presented in Examples 1-9 are
expected with other catalysts, cocatalysts, scavengers and process
parameters, all of which are disclosed above.
* * * * *