U.S. patent application number 13/797319 was filed with the patent office on 2013-10-24 for lubricant compositions comprising ethylene propylene copolymers and methods for making them.
This patent application is currently assigned to ExxonMobil Chemical Patents Inc.. The applicant listed for this patent is EXXONMOBIL CHEMICAL PATENTS INC.. Invention is credited to Rainer Kolb.
Application Number | 20130281340 13/797319 |
Document ID | / |
Family ID | 47997901 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130281340 |
Kind Code |
A1 |
Kolb; Rainer |
October 24, 2013 |
Lubricant Compositions Comprising Ethylene Propylene Copolymers and
Methods for Making Them
Abstract
Lubricant compositions, as well as processes for their
formulation, are provided. The lubricant compositions comprise an
oil basestock and one or more blocky ethylene propylene copolymers.
The copolymers are preferably prepared using metallocene catalyst
systems but without using a chain shuttling agent.
Inventors: |
Kolb; Rainer; (Kingwood,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EXXONMOBIL CHEMICAL PATENTS INC. |
Baytown |
TX |
US |
|
|
Assignee: |
ExxonMobil Chemical Patents
Inc.
Baytown
TX
|
Family ID: |
47997901 |
Appl. No.: |
13/797319 |
Filed: |
March 12, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61635650 |
Apr 19, 2012 |
|
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|
61635633 |
Apr 19, 2012 |
|
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Current U.S.
Class: |
508/591 |
Current CPC
Class: |
C08F 210/02 20130101;
C10M 143/00 20130101; C10N 2040/042 20200501; C08F 4/6592 20130101;
C08F 4/65927 20130101; C08F 4/65908 20130101; C10N 2030/68
20200501; C10M 2205/022 20130101; C08F 4/76 20130101; C08F 210/06
20130101; C10N 2040/252 20200501; C10N 2030/70 20200501; C10M
143/04 20130101; C10N 2040/08 20130101; C10N 2070/02 20200501; C08F
210/16 20130101; C10N 2040/255 20200501; C10N 2040/04 20130101;
C10N 2040/253 20200501; C08F 210/16 20130101; C08F 4/65908
20130101; C08F 210/16 20130101; C08F 4/65927 20130101; C08F 210/16
20130101; C08F 210/06 20130101; C08F 2500/17 20130101; C10M
2205/022 20130101; C10M 2205/024 20130101; C10N 2020/04 20130101;
C10N 2020/011 20200501; C10M 2205/022 20130101; C10M 2205/024
20130101; C10N 2020/04 20130101; C10N 2020/011 20200501 |
Class at
Publication: |
508/591 |
International
Class: |
C10M 143/04 20060101
C10M143/04 |
Claims
1. A lubricant composition comprising: a. an oil basestock; and b.
from about 0.5 to about 2.5 wt. %, based on the total weight of the
lubricant composition, of a copolymer of propylene and ethylene,
wherein the copolymer comprises from about 50 to about 95 wt. %
ethylene, the copolymer has a melting point greater than about
90.degree. C., and less than about 5 wt. % of the copolymer, based
upon the total weight of the copolymer, is soluble in xylene or
ortho-dichlorobenzene.
2. The lubricant composition of claim 1, wherein the copolymer
comprises from about 65 to about 90 wt. % ethylene.
3. The lubricant composition of claim 1, wherein the copolymer has
a melting point greater than about 100.degree. C.
4. The lubricant composition of claim 1, wherein the melting point
of the soluble fraction of the copolymer is greater than about
100.degree. C.
5. The lubricant composition of claim 1, wherein the lubricant
composition has a thickening efficiency from about 1.5 to about
3.5.
6. The lubricant composition of claim 1, wherein the lubricant
composition has a shear stability index from about 15% to about
25%.
7. The lubricant composition of claim 1, wherein the lubricant
composition has a shear stability index greater than or equal to
about 24%.
8. The lubricant composition of claim 1, wherein the copolymer is
not synthesized in the presence of a chain shuttling agent.
9. A lubricant composition comprising: a. an oil basestock; and b.
from about 7.5 to about 15.0 wt. %, based on the total weight of
the lubricant composition, of a copolymer of propylene and
ethylene, wherein the copolymer comprises from about 50 to about 95
wt. % ethylene, the copolymer has a melting point greater than
about 90.degree. C., and less than about 5 wt. % of the copolymer,
based upon the total weight of the copolymer, is soluble in xylene
or ortho-dichlorobenzene.
10. The lubricant composition of claim 9, wherein the copolymer
comprises from about 65 to about 90 wt. % ethylene.
11. The lubricant composition of claim 9, wherein the copolymer has
a melting point greater than about 100.degree. C.
12. The lubricant composition of claim 9, wherein the melting point
of the soluble fraction of the copolymer is greater than about
100.degree. C.
13. The lubricant composition of claim 9, wherein the copolymer is
not synthesized in the presence of a chain shuttling agent.
14. The lubricant composition of claim 9, wherein the oil basestock
comprises one or more oils and a pour point depressant.
15. The lubricant composition of claim 9, wherein the lubricant
composition has a thickening efficiency from about 1.5 to about
3.5.
16. The lubricant composition of claim 9, wherein the lubricant
composition has a shear stability index from about 15% to about
25%.
17. The lubricant composition of claim 9, wherein the lubricant
composition has a shear stability index greater than or equal to
about 24%.
18. A process for making a lubricant composition comprising:
combining (a) an oil basestock, and (b) from about 0.5 to about 2.5
wt. %, based on the total weight of the lubricant composition, of a
copolymer of propylene and ethylene, wherein the copolymer
comprises from about 50 to about 95 wt. % ethylene, the copolymer
has a melting point greater than about 90.degree. C., and less than
about 5 wt. % of the copolymer, based upon the total weight of the
copolymer, is soluble in xylene or ortho-dichlorobenzene.
19. The process of claim 18, wherein the copolymer is prepared by:
polymerizing propylene and ethylene in a solution process and in
the presence of a catalyst system comprising a catalyst and an
activator to form a copolymer of propylene and ethylene; a. wherein
the catalyst comprises a metallocene compound; b. wherein the
activator comprises a cationic component and an anionic component;
c. wherein the cationic component of the activator corresponds to
the formula: iii. [R.sup.1R.sup.2R.sup.3NH].sup.+, where R.sup.1
and R.sup.2 are together a --(CH.sub.2).sub.a-- group, where a is
3, 4, 5, or 6 and R.sup.1 and R.sup.2 form a 4-, 5-, 6-, or
7-membered non-aromatic ring together with the nitrogen atom to
which one or more aromatic or heteroaromatic rings may optionally
be fused via adjacent ring carbon atoms; and R.sup.3 is a
C.sub.1-C.sub.5 alkyl group; or iv. [R.sub.3NH].sup.+, where all R
are identical and are C.sub.1-C.sub.3 alkyl groups; and d. wherein
the anionic component of the activator corresponds to the formula
[B(R.sup.4).sub.4].sup.-, where R.sup.4 is an aryl group or a
substituted aryl group having one or more substituents, wherein the
one or more substituents are identical or different and are
selected from alkyl, aryl, halogenated aryl, or haloalkylaryl
groups or a hydrogen atom.
20. The process of claim 18, wherein the copolymer is prepared in
the absence of a chain shuttling agent.
21. The process of claim 18, wherein the copolymer comprises from
about 65 to about 90 wt. % ethylene.
22. The process of claim 18, wherein less than about 5 wt. % of the
copolymer, based upon the total weight of the copolymer, is soluble
in xylene or ortho-dichlorobenzene.
23. The process of claim 19, wherein the metallocene compound is a
dialkylsilyl-bridged bis(indenyl transition metal compound or Group
4 metal compound.
24. The process of claim 19, wherein the cationic component of the
activator is selected from N-methylpyrrolidinium,
N-methylpiperidinium, trimethylammonium, or triethylammonium; and
the anionic component of the activator is selected from
tetrakis(pentafluorophenyl)borate or
tetrakis(heptafluorophenyl)borate.
25. The process of claim 18, where from about 0.5 to about 1.5 wt.
% of the copolymer, based on the total weight of the lubricant
composition, is combined with the oil basestock.
Description
PRIORITY CLAIM
[0001] This application claims the benefit of and priority to U.S.
Provisional Application Nos. 61/635,650 and 61/635,633, both filed
on Apr. 19, 2012, both of which are herein incorporated by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to ethylene propylene
copolymers ("EP copolymers") useful as rheology modifiers. More
particularly, the invention relates to lubricating compositions
comprising an oil basestock and one or more blocky EP copolymers
and to processes for formulating such compositions. The blocky
copolymers have semicrystalline ethylene sequences and amorphous or
low crystallinity propylene sequences. The polymers may be prepared
using metallocene-based catalyst systems and preferably without the
use of a chain shuttling agent. The polymers have higher melting
temperatures than previously known random copolymers or block
copolymers prepared with chain shuttling agents.
BACKGROUND OF THE INVENTION
[0003] Lubrication fluids are applied between moving surfaces to
reduce friction, thereby improving efficiency and reducing wear.
Lubrication fluids also often function to dissipate the heat
generated by moving surfaces.
[0004] One type of lubrication fluid is a petroleum-based
lubrication oil used for internal combustion engines. Lubrication
oils contain additives that help the lubrication oil exhibit a
certain viscosity at a given temperature. In general, the viscosity
of lubrication oils and fluids is inversely dependent upon
temperature. When the temperature of a lubrication fluid is
increased, the viscosity generally decreases, and when the
temperature is decreased, the viscosity generally increases. For
internal combustion engines, for example, it is desirable to have a
lower viscosity at low temperatures to facilitate engine starting
during cold weather, and a higher viscosity at higher ambient
temperatures when lubrication properties typically decline.
[0005] Additives for lubrication fluids and oils include rheology
modifiers, such as viscosity index (VI) improvers. VI improving
components, many of which are derived from ethylene-alpha-olefin
copolymers, modify the rheological behavior of a lubricant to
increase viscosity and promote a more constant viscosity over the
range of temperatures at which the lubricant is used. Higher
ethylene content copolymers efficiently promote oil thickening and
shear stability. However, higher ethylene content copolymers also
tend to flocculate or aggregate in oil formulations leading to very
viscous and potentially solid formulations. Flocculation typically
happens at ambient or subambient conditions of controlled and
quiescent cooling. This deleterious property of otherwise
advantageous higher ethylene content viscosity improvers is
measured by low temperature solution rheology. Various remedies
have been proposed for these higher ethylene content copolymer
formulations to overcome or mitigate the propensity towards the
formation of high viscosity flocculated materials.
[0006] One proposed solution is the use of blends of amorphous and
semicrystalline ethylene-based copolymers for lubricant oil
formulations. The combination of two such ethylene-propylene
copolymers allows for increased thickening efficiency, shear
stability index, low temperature viscosity performance and pour
point. See, e.g., U.S. Pat. Nos. 7,402,235 and 5,391,617, and
European Patent No. 0 638 611, the disclosures of which are
incorporated herein by reference.
[0007] There remains a need, however, for lubricant compositions
comprising ethylene and propylene suitable for use in VI improvers
which have good thickening efficiency compared to prior
compositions while still being equivalent in their beneficial low
temperature solution rheology properties. The present invention
addresses this by providing blocky ethylene propylene copolymers
having amorphous propylene sequences and semicrystalline ethylene
sequences together in the same polymer. The copolymers are
preferably polymerized without the added complexity and expense of
a chain shuttling agent.
SUMMARY OF THE INVENTION
[0008] The present invention relates to lubricant compositions and
concentrates comprising ethylene propylene copolymer compositions
"EP copolymers" having blocky structures that are useful for
modifying the rheological properties of the lubricants. The present
invention also relates to processes for formulating such lubricant
compositions. The blocky EP copolymers comprise from about 50 to
about 95 wt. % ethylene and have a melting temperature greater than
about 90.degree. C. Preferably, less than about 5 wt. % of the
copolymer, based upon the total weight of the copolymer, is soluble
in xylene or ortho-dichlorobenzene (ODCB).
[0009] The performance of ethylene-based rheology modifiers as VI
improvers can be measured by the thickening efficiency (TE) and the
shear stability index (SSI), and by the ratio of TE to SSI. It is
generally believed that the composition of an olefin copolymer at a
given SSI largely determines the TE, and that higher ethylene
content is preferred because of its TE. While increasing the
ethylene content of rheology modifiers can lead to improved TE/SSI
ratios, it may also lead to increasing crystallinity of the olefin
copolymer. Increasing crystallinity, however, detracts from the
performance of a rheology modifier as a VI improver because
crystalline polymers tend to flocculate, either by themselves or in
association with other components of the lubrication oil, and
precipitate out of lubrication oils. These precipitates are
apparent as regions (e.g., "lumps") of high viscosity or
essentially complete solidification (e.g., "gels") and can lead to
clogs and blockages of pumps and other passageways for the
lubrication fluid and can harm and in some cases cause failure of
moving machinery.
[0010] While not wishing to be bound by any particular theory, it
is believed that rheology modifiers for lubrication fluids
comprising blocky ethylene-based copolymers that have amorphous or
low crystallinity regions in combination with semicrystalline
regions will be less prone to the deleterious effects of
macroscopic crystallization in dilute solution, as measured by the
change in the rheology of the fluid solution compared to an
equivalent amount of a random ethylene-based copolymer of the same
average composition as the blocky copolymer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows melting temperature versus ethylene content for
ethylene-rich EP copolymers of the invention, as well as for
comparative ethylene-rich copolymers.
DEFINITIONS
[0012] As used herein, the term "copolymer" includes polymers
having two or more monomers, optionally with other monomers, and
may refer to interpolymers, terpolymers, etc. "EP copolymer," as
used herein, refers to polymers comprising ethylene-derived and
propylene-derived units. The term "polymer" as used herein
includes, but is not limited to, homopolymers, copolymers,
terpolymers, etc., and alloys and blends thereof. The term
"polymer" as used herein also includes impact, block, graft, random
and alternating copolymers. The term "polymer" shall further
include all possible geometrical configurations unless otherwise
specifically stated. Such configurations may include isotactic,
syndiotactic and random symmetries.
[0013] As used herein, the term "monomer" or "comonomer" refers to
the monomer used to form the polymer, i.e., the unreacted chemical
compound in the form prior to polymerization, and can also refer to
the monomer after it has been incorporated into the polymer, also
referred to herein as a "[monomer]-derived unit", which by virtue
of the polymerization reaction typically has fewer hydrogen atoms
than it does prior to the polymerization reaction. Different
monomers are discussed herein, including propylene monomers,
ethylene monomers, and other .alpha.-olefin monomers. For the
purposes of this invention, it is understood that whenever a
polymer is referred to as "comprising" an olefin or other monomer,
the olefin present in the polymer is the polymerized form of the
olefin or other monomer, respectively.
[0014] As used herein, "ethylene-rich" or "ethylene-based" refers
to polymers comprising greater than 50 wt. % units derived from
ethylene.
[0015] As used herein, "block" or "blocky" when used to describe
copolymers refers to copolymers having statistically significant
sequences of the same repeating monomer units. Block (or blocky)
copolymers described herein are distinguished from random polymers,
i.e., those having random statistical distribution of monomer
units. In block copolymers, the average length of sequences of the
same repeating monomer unit is greater than in a random copolymer
with a similar composition. Within the context of the invention,
the term "sequence" describes a number of contiguous olefin monomer
residues catenated together by chemical bonds and obtained by a
polymerization procedure. Whereas random copolymers often have
properties, such as melting temperatures or glass transition
temperatures, that are an average of the properties of the
homopolymers comprising the copolymer, block copolymers often
retain the characteristics of the corresponding homopolymers in
each block.
[0016] As used herein, a "catalyst system" is a combination of
different components that, taken together, provide the active
catalyst. A catalyst system may therefore comprise at least a
transition metal compound (also referred to herein as "catalyst,"
"precatalyst," or "catalyst precursor," these terms being identical
in meaning and used interchangeably herein) and an activator. An
activator is also sometimes referred to as a "co-catalyst" (these
terms are again identical in meaning and used interchangeably
herein). The activator activates the transition metal compound and
converts it into its catalytically active form. For example, an
activator converts a neutral metallocene compound into its cationic
form, which is the catalytically active species. When the term
"catalyst system" is used to describe a catalyst/activator pair
before activation, it refers to the unactivated catalyst (i.e., the
precatalyst) together with an activator. When this term is used to
describe a catalyst/activator pair after activation, it refers to
the activated catalyst and the charge-balancing anion derived from
the activator or other charge-balancing moiety. In the scientific
and commercial literature the term "catalyst" is sometimes used to
refer to the non-activated (i.e., neutral and stable) metallocene,
which still has to be converted to its respective charged form in
order to react with the monomers to produce polymer. The components
of the catalyst system may, either separately or jointly, be
supported on a solid support, such as alumina or silica.
[0017] A "scavenger" is a compound that is typically added to
facilitate polymerization by scavenging impurities (poisons that
would otherwise react with the catalyst and deactivate it). Some
scavengers may also act as activators, and they may also be
referred to as co-activators. A co-activator may be used in
conjunction with an activator in order to form an active
catalyst.
[0018] The terms "radical," "group," and "substituent" are used
interchangeably herein and indicate a group that is bound to a
certain atom as indicated herein. A "substituted" group is one in
which a hydrogen has been replaced by a hydrocarbyl, a heteroatom
or a heteroatom containing group. For example, methyl
cyclopentadiene is a cyclopentadiene substituted with a methyl
group.
[0019] The term "hydrocarbyl" is used herein to refer to any
hydrocarbon-derived substituent or group and thus is understood to
include, without limitation, linear, branched or cyclic alkyl,
alkylene, alkene, alkyne, as well as aryl groups. Any of these
groups may be substituted or unsubstituted.
[0020] The term "alkyl" is used herein to refer to an aliphatic,
branched or linear, non-cyclic or cyclic substituent, typically
with a certain number of carbon atoms as individually specified.
Unless specified otherwise herein, "alkyl" specifically includes
aliphatic groups having from 1 to 20, or from 1 to 10, or from 1 to
5 carbon atoms, and specifically methyl, ethyl, propyl, n-propyl,
isopropyl, butyl, n-butyl, isobutyl, pentyl, n-pentyl, isopentyl,
cyclopentyl, hexyl, n-hexyl, isohexyl, cyclohexyl, heptyl,
n-heptyl, isohexyl, cycloheptyl, octyl, n-octyl, isooctyl,
cyclooctyl, nonyl, n-nonyl, isononyl, decyl, n-decyl, iso-decyl,
and the like. The same definition applies for the alkyl in an
alkoxy substituent.
[0021] The term "aryl" is used herein to refer to an aromatic
substituent, which may be a single aromatic ring or multiple
aromatic rings, which are fused together, covalently linked, or
linked to a common group such as a methylene or ethylene moiety.
The common linking group may also be a carbonyl as in benzophenone
or oxygen as in diphenylether. The aromatic ring(s) may include
phenyl, naphthyl, fluorenyl, indenyl, biphenyl, diphenylether,
tolyl, cumyl, xylyl, and benzophenone, among others. Unless
specified otherwise herein, the term "aryl" specifically includes
those having from 5 to 30, or from 5 to 25, or from 5 to 20, or
from 5 to 15 carbon atoms, alternately the aryl may have 6 to 15
carbon atoms or may have 5 or 6 carbon atoms. "Substituted aryl"
refers to aryl as just described in which one or more hydrogen
atoms to any carbon are, independently of each other, replaced by
one or more groups such as alkyl, substituted alkyl, cycloalkyl,
substituted cycloalkyl, heterocycloalkyl, substituted
heterocycloalkyl, halogen, alkylhalogen, such as hydroxyl-,
phosphino-, alkoxy-, aryloxy-, amino-, thio- and both saturated and
unsaturated cyclic hydrocarbons which are fused to the aromatic
ring(s), linked covalently or linked to a common group such as a
methylene or ethylene moiety. The linking group may also be a
carbonyl such as in cyclohexyl phenyl ketone. The term "aryl" also
includes aromatic groups containing one or more heteroatoms, such
as nitrogen, oxygen, phosphorus, or sulfur. Non-limiting examples
of such hetero-atom containing aromatic groups are furanyl,
thiophenyl, pyridinyl, pyrrolyl, imidazolyl, pyrazolyl,
benzofuranyl, pyrazinyl, pyrimidinyl, pyridazinyl, chinazolinyl,
indolyl, carbazolyl, oxazolyl, thiazolyl, and the like.
[0022] The term "ring system" refers to any system or combination
of aliphatic and/or aromatic rings that are fused to each other via
shared ring member atoms, that are covalently linked to each other,
or that are linked via a common linking group, such as an alkylene
group or a hetero-atom containing group such as carbonyl. One or
more of the aliphatic and/or aromatic rings of the ring system may
also contain one or more heteroatoms, such as nitrogen, oxygen,
phosphorus or sulfur. Any of the aliphatic and/or aromatic rings of
the ring system may be substituted by one or more groups such as
alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl,
heterocycloalkyl, substituted heterocycloalkyl, halogen,
alkylhalogen, such as hydroxyl-, phosphino-, alkoxy-, aryloxy-,
amino-, thio- and both saturated and unsaturated cyclic
hydrocarbons. For the aromatic or aliphatic rings of the ring
system, the above-provided definitions for "aryl" and "alkyl"
regarding the number of carbon atoms apply as well. A ring system
in the context of the present invention contains at least two
rings. A "ring carbon atom" is a carbon atom that is part of a
cyclic ring structure. By this definition, a benzyl group has six
ring carbon atoms and para-methylstyrene also has six ring carbon
atoms.
[0023] The term "amino" is used herein to refer to the group
--NQ.sup.1Q.sup.2, where each of Q.sup.1 and Q.sup.2 is
independently selected from the group consisting of hydrogen,
alkyl, substituted alkyl, cycloalkyl, substituted cycloalkyl,
heterocycloalkyl, substituted heterocycloalkyl, aryl, substituted
aryl, heteroaryl, substituted heteroaryl, alkoxy, aryloxy, silyl
and combinations thereof.
[0024] As used herein, the term "complex viscosity" means a
frequency-dependent viscosity function determined during forced
small amplitude harmonic oscillation of shear stress, in units of
Pascal-seconds, that is equal to the difference between the dynamic
viscosity and the out-of-phase viscosity (imaginary part of complex
viscosity).
[0025] As used herein, the numbering scheme for the Periodic Table
Groups is as published in Chemical and Engineering News, 63(5), 27
(1985).
DETAILED DESCRIPTION OF THE INVENTION
[0026] The present invention is directed to lubricant compositions
(including concentrates) comprising rheology modifying blocky EP
copolymers and to processes for formulating such compositions. In
particular, the blocky EP copolymers have semicrystalline ethylene
sequences and amorphous or low crystallinity propylene sequences.
The polymers are preferably prepared using metallocene catalyst
systems but without the use of a chain shuttling agent. The
polymers have higher melting temperatures than previously known
random copolymers or blocky copolymers prepared with chain
shuttling agents and having similar comonomer contents.
[0027] The presence of blocky characteristics in the polymers can
be shown by their high melting temperature when compared to random
copolymers having the same comonomer composition. Further
indication of blockiness can be found in the poor solubility of the
polymers in multiple solvents, including xylene and
ortho-dichlorobenzene (ODCB).
Test Methods
[0028] The following test methods are used to determine the
properties reported herein.
[0029] Gel Permeation Chromatography (GPC)--Techniques for
determining the molecular weight (Mn, Mw and Mz) and MWD may be
found in U.S. Pat. No. 4,540,753 (Cozewith, Ju and Verstrate),
incorporated by reference herein, and references cited therein, and
in Macromolecules, 1988, Vol. 21, p. 3360 (Verstrate et al.), which
is incorporated by reference herein, and references cited therein.
For example, molecular weight may be determined by size exclusion
chromatography (SEC) by using a Waters 150 gel permeation
chromatograph equipped with the differential refractive index
detector and calibrated using polystyrene standards.
[0030] Differential Scanning calorimetry (DSC)--DSC procedures for
determining peak melting temperature (Tm), crystallization
temperature (Tc), and heat of fusion (Hf) include the following.
The polymer is pressed at a temperature of from about 200.degree.
C. to about 230.degree. C. in a heated press, and the resulting
polymer sheet is hung, under ambient conditions, in the air to cool
at room temperature (approximately 23.degree. C.). About 6 to 10 mg
of the polymer sheet is removed with a punch die. This 6 to 10 mg
sample is annealed at room temperature for about 80 to 100 hours.
At the end of this period, the sample is placed in a DSC (Perkin
Elmer Pyris One Thermal Analysis System) and cooled to about
-70.degree. C. The sample is heated at 10.degree. C./min to attain
a final temperature of about 200.degree. C. The sample is kept at
200.degree. C. for 5 minutes and a second cool-heat cycle is
performed. Events from both cycles are recorded. The thermal output
is recorded as the area under the melting peak of the sample, which
typically occurs between about 0.degree. C. and about 200.degree.
C. It is measured in Joules and is a measure of the Hf of the
polymer.
[0031] Comonomer Content--The ethylene content of
ethylene/propylene copolymers was determined using FTIR according
to the following technique. A thin homogeneous film of polymer,
pressed at a temperature of about 150.degree. C., was mounted on a
Perkin Elmer Spectrum 2000 infrared spectrophotometer. A full
spectrum of the sample from 600 cm.sup.-1 to 4000 cm.sup.-1 was
recorded and the area under the propylene band at .about.1165
cm.sup.-1 and the area under the ethylene band at .about.732
cm.sup.-1 in the spectrum were calculated. The baseline integration
range for the methylene rocking band is nominally from 695
cm.sup.-1 to the minimum between 745 and 775 cm.sup.-1. For the
polypropylene band the baseline and integration range is nominally
from 1195 to 1126 cm.sup.-1. The ethylene content in wt. % was
calculated according to the following equation:
ethylene content(wt.%)=72.698-86.495X+13.696X.sup.2,
where X=AR/(AR+1) and AR is the ratio of the area for the peak at
.about.1165 cm.sup.-1 to the area of the peak at .about.732
cm.sup.-1.
[0032] Temperature Rising Elution Fractionation (TREF)--The TREF
data reported herein were measured using an analytical size TREF
instrument (Polymerchar, Spain), with a column of the following
dimensions: inner diameter (ID) 7.8 mm, outer diameter (OD) 9.53
mm, and column length of 150 mm. The column was filled with steel
beads. 0.5 mL of a 4 mg/mL polymer solution in
ortho-dichlorobenzene (ODCB) containing 2 g butylated
hydroxyl-toluene (BHT)/4 L were charged onto a the column and
cooled from 140.degree. C. to -15.degree. C. at a constant cooling
rate of 1.0.degree. C./min. Subsequently, ODCB was pumped through
the column at a flow rate of 1.0 mL/min, and the column temperature
was increased at a constant heating rate of 2.degree. C./min to
elute the polymer. The polymer concentration in the eluted liquid
was detected by means of measuring the absorption at a wavenumber
of 2941 cm.sup.-1 using an infrared detector. The concentration of
the ethylene-.alpha.-olefin copolymer in the eluted liquid was
calculated from the absorption and plotted as a function of
temperature.
[0033] Fractionation--Copolymers were fractionated using the TREF
method described above. In order to obtain individual fractions in
sufficient quantity for additional analysis, solvent with polymer
eluting at the following three temperature ranges was collected:
15.degree. C. to 0.degree. C.; >0.degree. C. to +10.degree. C.;
and >10.degree. C. to 130.degree. C. The solvent was evaporated
and the dried polymers collected at these ranges were further
analyzed by DSC for thermal properties and by IR spectroscopy for
ethylene content.
[0034] Thickening Efficiency (TE) was determined according to ASTM
D445.
[0035] Shear Stability index (SSI) was determined according to ASTM
D6278 at 30 and 90 cycles using a Kurt Orbahn (KO) machine.
Ethylene-Rich Blocky Copolymers
[0036] Provided herein are rheology modifying EP copolymers
comprising propylene and ethylene, wherein the copolymer comprises
from about 50 to about 95 wt. % ethylene, the copolymer has a
melting temperature greater than about 90.degree. C., and less than
about 5 wt. % of the copolymer, based upon the total weight of the
copolymer, is soluble in xylene or ortho-dichlorobenzene.
[0037] The EP copolymers may comprise from about 50 to about 95 wt.
%, or from about 52 to about 93 wt. %, or from about 55 to about 90
wt. %, or from about 57 to about 87 wt. %, or from about 60 to
about 85 wt. %, or from about 65 to about 85 wt. %, or from about
70 to about 85 wt. %, or from about 75 to about 85 wt. % ethylene
derived units.
[0038] The EP copolymers may have a melting temperature of from
about 90.degree. C. to about 200.degree. C., or from about
95.degree. C. to about 200.degree. C., or from about 100.degree. C.
to about 180.degree. C., or from about 105.degree. C. to about
180.degree. C., or from about 110.degree. C. to about 180.degree.
C., or from about 112.degree. C. to about 160.degree. C., or from
about 114.degree. C. to about 160.degree. C., or from about
115.degree. C. to about 160.degree. C.
[0039] The EP copolymers may have a weight-average molecular weight
(Mw) in g/mol, determined using GPC, of from about 10,000 to about
500,000, or from about 25,000 to about 125,000, or from about
40,000 to about 115,000, or from about 45,000 to about 110,000, or
from about 50,000 to about 100,000, or from about 50,000 to about
80,000.
[0040] The EP copolymers may have a number-average molecular weight
(Mn) in g/mol, determined using GPC, from about 4,000 to about
40,000, or from about 5,000 to about 35,000, or from about 6,000 to
about 30,000, or from about 7,000 to about 30,000, or from about
8,000 to about 30,000, or from about 10,000 to about 30,000, or
from about 12,000 to about 28,000.
[0041] The EP copolymers may have a z-average molecular weight (Mz)
in g/mol, determined using GPC, from about 50,000 to about 300,000,
or from about 75,000 to about 275,000, or from about 100,000 to
about 250,000, or from about 110,000 to about 225,000, or from
about 115,000 to about 200,000, or from about 115,000 to about
175,000.
[0042] The EP copolymers may have a molecular weight distribution
(MWD), Mw/Mn, from about 2.0 to about 10.0, or from about 2.0 to
about 9.0, or from about 2.0 to about 8.0, or from about 2.5 to
about 7.0, or from about 2.5 to about 6.5, or from about 2.5 to
about 6.0, or from about 2.0 to about 5.0, or from about 2.5 to
about 5.0.
[0043] The EP copolymers may have a density in the range of from
0.85 g/cc to 0.97 g/cc, or in the range of from 0.86 g/cc to 0.94
g/cc, or in the range of from 0.86 g/cc to 0.91 g/cc, or in the
range of from 0.86 g/cc to 0.90 g/cc.
[0044] The fraction of the EP copolymer that is soluble in xylene
or ODCB is less than about 15 wt. %, or less than about 10 wt. %,
or less than about 7.5 wt. %, or less than about 5 wt. %, or less
than about 4 wt. %, or less than about 3 wt. %. The melting
temperature of the soluble fraction may be greater than about
90.degree. C., or greater than about 95.degree. C., or greater than
about 100.degree. C., or greater than about 105.degree. C., or
greater than about 110.degree. C., or greater than about
115.degree. C.
[0045] The melting temperature of the EP copolymer may be at least
about 5.degree. C., or at least about 10.degree. C., or at least
about 15.degree. C., or at least about 20.degree. C., or at least
about 25.degree. C. greater than that of a random copolymer having
the same or similar comonomer composition. In some embodiments, the
melting temperature of the EP copolymer may also be at least about
5.degree. C., or at least about 10.degree. C., or at least about
15.degree. C., or at least about 20.degree. C., or at least about
25.degree. C. greater than that of a blocky copolymer having the
same comonomer composition but synthesized in the presence of a
chain shuttling agent. Additionally, the melting temperature of the
soluble fraction of the copolymers may be at least about 5.degree.
C., or at least about 10.degree. C., or at least about 15.degree.
C., or at least about 20.degree. C., or at least about 25.degree.
C. greater than that of the soluble fraction of a blocky copolymer
having the same or similar comonomer composition but synthesized in
the presence of a chain shuttling agent. Chain shuttling agents are
described in, e.g., U.S. Publication Nos. 2007/0167578 and
2008/0311812.
Processes for Preparing Blocky EP Copolymers
[0046] Also provided herein are processes for preparing the
rheology modifying EP copolymers. Such processes may comprise
polymerizing propylene and ethylene in a solution process and in
the presence of a catalyst system comprising a catalyst and an
activator where the catalyst comprises a metallocene compound as
described in further detail below, and the activator comprises a
cationic component and an anionic component, each also described in
further detail below. In one or more embodiments, the copolymers of
the present invention are prepared without the use of a chain
shuttling agent.
[0047] The cationic component of the activator may correspond to
either formula (1A) or formula (2A):
[R.sub.1R.sub.2R.sub.3NH].sup.+, (1A)
[0048] where R.sub.1 and R.sub.2 are together a
--(CH.sub.2).sub.a-- group, where a is 3, 4, 5, or 6 and R.sub.1
and R.sub.2 form a 4-, 5-, 6-, or 7-membered non-aromatic ring
together with the nitrogen atom to which one or more aromatic or
heteroaromatic rings may optionally be fused via adjacent ring
carbon atoms; and R.sub.3 is a C.sub.1-C.sub.5 alkyl group; or
[R.sub.3NH].sup.+, (2A)
[0049] where all R are identical and are C.sub.1-C.sub.3 alkyl
groups.
[0050] The anionic component of the activator may correspond to
formula (3A):
[B(R.sub.4).sub.4].sup.-, (3A)
[0051] where R.sub.4 is an aryl group or a substituted aryl group
having one or more substituents, wherein the one or more
substituents are identical or different and are selected from
alkyl, aryl, halogenated aryl, or haloalkylaryl groups or a
hydrogen atom, as further described in U.S. Pat. No. 7,985,816.
Transition Metal Compounds
[0052] Any transition metal compound capable of catalyzing a
reaction such as a polymerization reaction, upon activation of an
activator as described herein is suitable for use in the present
invention. Transition metal compounds known as metallocenes are
preferred compounds according to the present invention. Useful
metallocene compounds are described in greater detail in U.S.
Publication No. 2010/0029873, which is incorporated herein by
reference in its entirety.
[0053] Preferably, the transition metal compound is represented by
the formula: T(L.sub.1)(L.sub.2)M(X.sub.1)(X.sub.2), wherein the
metal (M) is a Group 4 metal, specifically, titanium, zirconium, or
hafnium, and the indenyl (L) is unsubstituted or may be substituted
by one or more substituents selected from the group consisting of a
halogen atom, C.sub.1 to C.sub.10 alkyl, C.sub.5 to C.sub.15 aryl,
C.sub.6 to C.sub.25 arylalkyl, and C.sub.6 to C.sub.25 alkylaryl.
More preferably, the metal is zirconium or hafnium, L.sub.1 and
L.sub.2 are unsubstituted or substituted indenyl radicals. T may be
a dialkylsiladiyl, and X.sub.1 and X.sub.2 are both halogen or a
C.sub.1 to C.sub.3 alkyl. Preferably, these compounds are in the
rac-form. In the formula above, T is bound to L.sub.1 and L.sub.2;
L.sub.1 and L.sub.2 are each bound to M to form a cyclic structure;
and X.sub.1 and X.sub.2 are each bound to M. Preferably the
transition metal compound is a dimethylsilylbis(indenyl)metallocene
where X.sub.1 and X.sub.2 are both halogen or a C.sub.1 to C.sub.3
alkyl.
[0054] Illustrative, but not limiting examples of preferred
stereospecific metallocene compounds are the racemic isomers of
dimethylsilylbis(indenyl)metal dichloride, -diethyl or -dimethyl,
wherein the metal is titanium, zirconium or hafnium, preferably
hafnium or zirconium. It is particularly preferred that the indenyl
radicals are not substituted by any further substituents. The two
indenyl groups may be, independently of each other, indenyl,
2-methyl-4-phenylindenyl; 2-methyl indenyl;
2-methyl,4-[3',5'-di-t-butylphenyl]indenyl;
2-ethyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-n-propyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-iso-propyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-iso-butyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-n-butyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-sec-butyl-4-[3',5'-di-t-butylphenyl]indenyl;
2-methyl-4-[3',5'-di-phenylphenyl]indenyl;
2-ethyl-4-[3',5'-di-phenylphenyl]indenyl;
2-n-propyl-4-[3',5'-di-phenylphenyl]indenyl;
2-iso-propyl-4-[3',5'-di-phenylphenyl]indenyl;
2-n-butyl-4-[3',5'-di-phenylphenyl]indenyl;
2-sec-butyl-4-[3',5'-di-phenylphenyl]indenyl;
2-tert-butyl-4-[3',5'-di-phenylphenyl]indenyl; and the like.
Further illustrative, but not limiting examples of preferred
stereospecific metallocene compounds are the racemic isomers of
9-silafluorenylbis(indenyl)metal dichloride, -diethyl or -dimethyl,
wherein the metal is titanium, zirconium or hafnium. Again,
unsubstituted indenyl radicals are particularly preferred. In some
embodiments, however, the two indenyl groups may be replaced,
independently of each other, by any of the substituted indenyl
radicals listed above.
[0055] Particularly preferred metallocenes as transition metal
compounds for use in the catalyst systems of the present invention
together with the activators include a cation of formula (1A) or
(2A) defined above for use in polymerizing olefins are
rac-dimethylsilylbis(indenyl)hafnocenes or -zirconocenes,
rac-dimethylsilylbis(2-methyl-4-phenylindenyl)hafnocenes or
-zirconocenes, rac-dimethylsilylbis(2-methyl-indenyl)hafnocenes or
-zirconocenes, and
rac-dimethylsilylbis(2-methyl-4-naphthylindenyl)hafnocenes or
-zirconocenes, wherein the hafnium and zirconium metal is
substituted, in addition to the bridged bis(indenyl) substituent,
by two further substituents, which are halogen, preferably chlorine
or bromine atoms, or alkyl groups, preferably methyl and/or ethyl
groups. Preferably, these additional substituents are both chlorine
atoms or both methyl groups. Particularly preferred transition
metal compounds are dimethylsilylbis(indenyl)hafnium dimethyl,
rac-dimethylsilylbis(indenyl)zirconium dimethyl,
rac-ethylnylbis(indenyl)zirconium dimethyl, and
rac-ethylnylbis(indenyl)hafnium dimethyl.
[0056] Illustrative, but not limiting examples of preferred
non-stereospecific metallocene catalysts are:
[dimethylsilanediyl(tetramethylcyclopentadienyl)-(cyclododecylamido)]meta-
l dihalide,
[dimethylsilanediyl(tetramethylcyclopentadienyl)(t-butylamido)]metal
dihalide,
[dimethylsilanediyl(tetramethylcyclopentadienyl)(exo-2-norborny-
l)]metal dihalide, wherein the metal is Zr, Hf, or Ti, preferably
Ti, and the halide is preferably chlorine or bromine.
[0057] In preferred embodiments, the transition metal compound is a
bridged or unbridged bis(substituted or unsubstituted
indenyl)hafnium dialkyl or dihalide.
Activators and Activation Methods
[0058] The transition metal compounds described herein are
activated to yield a catalytically active, cationic transition
metal compound having a vacant coordination site to which a monomer
will coordinate and then be inserted into the growing polymer
chain. In the process for polymerizing the EP copolymers described
herein, an activator of one of the following general formulas (1)
or (2) may be used to activate the transition metal compound:
[R.sup.1R.sup.2R.sup.3AH].sup.+[Y].sup.-, (1)
where [Y].sup.- is a non-coordinating anion (NCA) as further
illustrated below, A is nitrogen or phosphorus, R.sup.1 and R.sup.2
are hydrocarbyl groups or heteroatom-containing hydrocarbyl groups
and together form a first, 3- to 10-membered non-aromatic ring with
A, wherein any number of adjacent ring members may optionally be
members of at least one second, aromatic or aliphatic ring or
aliphatic and/or aromatic ring system of two or more rings, wherein
said at least one second ring or ring system is fused to said first
ring, and wherein any atom of the first and/or at least one second
ring or ring system is a carbon atom or a heteroatom and may be
substituted independently by one or more substituents selected from
the group consisting of a hydrogen atom, halogen atom, C.sub.1 to
C.sub.10 alkyl, C.sub.5 to C.sub.15 aryl, C.sub.6 to C.sub.25
arylalkyl, and C.sub.6 to C.sub.25 alkylaryl, and R.sup.3 is a
hydrogen atom or C.sub.1 to C.sub.10 alkyl, or R.sup.3 is a C.sub.1
to C.sub.10 alkylene group that connects to said first ring and/or
to said at least one second ring or ring system; or
[R.sub.nAH].sup.+[Y].sup.-, (2)
where [Y].sup.- is a non-coordinating anion (NCA) as further
illustrated below, A is nitrogen, phosphorus or oxygen, n is 3 if A
is nitrogen or phosphorus, and n is 2 if A is oxygen, and the
groups R are identical or different and are a C.sub.1 to C.sub.3
alkyl group.
[0059] Both the cation part of formulas (1) and (2) and the anion
part, which is a NCA, are described in further detail in U.S.
Publication No. 2010/0029873, which is incorporated by reference
herein in its entirety. Any combinations of cations and NCAs
disclosed therein are suitable to be used in the processes of the
present invention.
[0060] Preferred activators of formula (1) in the catalyst systems
used in the polymerization processes are those where A is nitrogen,
R.sup.1 and R.sup.2 together are a --(CH.sub.2).sub.a-- group with
A being 3, 4, 5, or 6, and R.sup.3 is C.sub.1, C.sub.2, C.sub.3,
C.sub.4 or C.sub.5 alkyl, and [Y].sup.- is
[B(R.sup.4).sub.4].sup.-, with R.sup.4 being an aryl group or a
substituted aryl group, of which the one or more substituents are
identical or different and are selected from the group consisting
of alkyl, aryl, a halogen atom, halogenated aryl, and haloalkylaryl
groups, and preferably R.sup.4 is a perhalogenated aryl group, more
preferably a perfluorinated aryl group, more preferably
pentafluorophenyl, heptafluoronaphthyl or perfluorobiphenyl.
Preferably, these activators are combined with a transition metal
compound (such as a metallocene) to form the catalyst systems of
the present invention.
[0061] Preferred activators in the catalyst systems of formula (2)
in the catalyst systems used in the polymerization process are
those wherein A is nitrogen, n is 3, all groups R are identical and
are methyl, ethyl or isopropyl, and [Y].sup.- is
[B(R.sup.4).sub.4].sup.-, with R.sup.4 being an aryl group or a
substituted aryl group, of which the one or more substituents are
identical or different and are selected from the group consisting
of alkyl, aryl, a halogen atom, halogenated aryl, and haloalkylaryl
groups, and preferably R.sup.4 is a perhalogenated aryl group, more
preferably a perfluorinated aryl group, more preferably
pentafluorophenyl, heptafluoronaphthyl or perfluorobiphenyl.
Preferably, these activators are combined with a transition metal
compound (such as a metallocene) to form the catalyst systems.
[0062] In the polymerization process, in addition to the preferred
activators of formula (1) mentioned in the preceding paragraph also
the activators of formula (2) wherein A is nitrogen and all groups
R are identically methyl or ethyl, and wherein [Y].sup.- is defined
as in the preceding paragraph are preferably used. Again, these
activators are preferably combined with a metallocene (e.g. as
explained herein below) to form the catalyst systems used in the
polymerization process.
Catalyst Systems
[0063] Preferred combinations of transition metal compound and
activator in the catalyst systems for olefin polymerization
comprise a metallocene compound and an activator comprising a
cationic component and an anionic component. In one or more
embodiments, the metallocene compound is preferably a
dialkylsilyl-bridged bis(indenyl)metallocene, wherein the metal is
a group 4 metal and the indenyl is unsubstituted, or if
substituted, is substituted by one or more substituents selected
from the group consisting of a C.sub.1 to C.sub.10 alkyl, C.sub.5
to C.sub.15 aryl, C.sub.6 to C.sub.25 arylalkyl, and C.sub.6 to
C.sub.25 alkylaryl; more preferably dimethylsilylbis(indenyl)metal
dichloride or -dimethyl, ethylenylbis(indenyl)metal dichloride or
-dimethyl, dimethylsilylbis(2-methyl-4-phenylindenyl)metal
dichloride or -dimethyl, dimethylsilylbis(2-methyl-indenyl)metal
dichloride or -dimethyl, and
dimethylsilylbis(2-methyl-4-naphthylindenyl)metal dichloride or
-dimethyl, wherein in all cases the metal may be zirconium or
hafnium.
[0064] In one or more embodiments, the cationic component is of the
formula [R.sup.1R.sup.2R.sup.3AH].sup.+, where preferably A is
nitrogen, R.sup.1 and R.sup.2 are together a --(CH.sub.2).sub.a--
group, wherein a is 3, 4, 5 or 6 and form, together with the
nitrogen atom, a 4-, 5-, 6- or 7-membered non-aromatic ring to
which, via adjacent ring carbon atoms, optionally one or more
aromatic or heteroaromatic rings may be fused, and R.sup.3 is
C.sub.1, C.sub.2, C.sub.3, C.sub.4 or C.sub.5 alkyl, more
preferably N-methylpyrrolidinium or N-methylpiperidinium; or of the
formula [R.sub.nAH].sup.+, where preferably A is nitrogen, n is 3
and all R are identical and are C.sub.1 to C.sub.3 alkyl groups,
more preferably trimethylammonium or triethylammonium.
[0065] In one or more embodiments, the anionic component is
[Y].sup.- which is an NCA, preferably of the formula
[B(R.sup.4).sub.4].sup.-, with R.sup.4 being an aryl group or a
substituted aryl group, of which the one or more substituents are
identical or different and are selected from the group consisting
of alkyl, aryl, a halogen atom, halogenated aryl, and haloalkylaryl
groups, preferably perhalogenated aryl groups, more preferably
perfluorinated aryl groups, and more preferably pentafluorophenyl,
heptafluoronaphthyl, or perfluorobiphenyl.
[0066] Preferably, the activator for use in any of the
polymerization processes according to the present invention is
trimethylammonium tetrakis(pentafluorophenyl)borate,
N-methylpyrrolidinium tetrakis(pentafluorophenyl)borate,
trimethylammonium tetrakis(heptafluoronaphthyl)borate, or
N-methylpyrrolidinium tetrakis(heptafluoronaphthyl)borate. The
metallocene is preferably rac-dimethylsilyl bis(indenyl)zirconium
dichloride or -dimethyl, rac-dimethylsilyl bis(indenyl)hafnium
dichloride or -dimethyl, rac-ethylnyl bis(indenyl)zirconium
dichloride or -dimethyl or rac-ethylnyl bis(indenyl)hafnium
dichloride or -dimethyl.
[0067] Any catalyst system resulting from any combination of the
preferred metallocene compound, preferred cationic component of the
activator, and preferred anionic component of the activator
mentioned in the preceding paragraphs shall be explicitly disclosed
and may be used in accordance with the polymerization of one or
more olefin monomers. Also, combinations of two different
activators can be used with the same or different
metallocene(s).
Scavengers or Additional Activators
[0068] The catalyst system may contain, in addition to the
transition metal compound and the activator described above,
additional activators or scavengers. A co-activator is a compound
capable of alkylating the transition metal complex, such that when
used in combination with an activator, an active catalyst is
formed. Co-activators include alumoxanes and aluminum alkyls. An
alumoxane is preferably an oligomeric aluminum compound represented
by the general formula (R.sup.x--Al--O).sub.n, which is a cyclic
compound, or R.sup.x (R.sup.x--Al--O).sub.nAlR.sup.x.sub.2, which
is a linear compound. Common alumoxanes are a mixture of cyclic and
linear compounds. In the general alumoxane formula, R.sup.x is
independently a C.sub.1-C.sub.20 alkyl radical, for example,
methyl, ethyl, propyl, butyl, pentyl, isomers thereof, and the
like, and "n" is an integer from 1-50. More preferably, R.sup.x is
methyl and "n" is at least 4. Methyl alumoxane (MAO) as well as
modified MAO, referred to herein as MMAO, containing some higher
alkyl groups to improve the solubility, ethyl alumoxane, iso-butyl
alumoxane and the like are useful herein. Particularly useful MAO
can be purchased from Albemarle in a 10 wt. % solution in toluene.
Co-activators are typically only used in combination with Lewis
acid activators and ionic activators when the pre-catalyst is not a
dihydrocarbyl or dihydride complex.
[0069] In some embodiments, scavengers may be used to "clean" the
reaction of any poisons that would otherwise react with the
catalyst and deactivate it. Typical aluminum or boron alkyl
components useful as scavengers are represented by the general
formula R.sup.xJZ.sub.2 where J is aluminum or boron, R.sup.x is a
C.sub.1-C.sub.20 alkyl radical, for example, methyl, ethyl, propyl,
butyl, pentyl, and isomers thereof, and each Z is independently
R.sup.x or a different univalent anionic ligand such as halogen
(Cl, Br, I), alkoxide (OR.sup.x) and the like. More preferred
aluminum alkyls include triethylaluminum, diethylaluminum chloride,
ethylaluminium dichloride, tri-iso-butylaluminum,
tri-n-octylaluminum, tri-n-hexylaluminum, trimethylaluminum, and
combinations thereof. Preferred boron alkyls include triethylboron.
Scavenging compounds may also be alumoxanes and modified alumoxanes
including methylalumoxane and modified methylalumoxane.
[0070] The catalyst systems of the present invention can be
prepared and supported according to methods known in the art. In
particular, methods for preparing the catalyst systems described
herein, as well as suitable supports and methods for supporting the
catalyst systems are described in detail in U.S. Publication No.
2010/0029873, which is incorporated by reference herein in its
entirety.
Polymerization Processes
[0071] The process for polymerizing ethylene and propylene may
comprise contacting ethylene and propylene under polymerization
conditions with a catalyst system comprising an activator of
formula (1) or formula (2) as defined above.
[0072] In particular, the polymerization processes exclude the use
of or are substantially free from the use of a chain shuttling
agent during polymerization. Known shuttling agents include, but
are not limited to, diethylzinc, di(i-butyl)zinc, di(n-hexyl)zinc,
triethylaluminum, trioctylaluminum, triethylgallium,
i-butylaluminum bis(dimethyl(t-butyl)siloxane), i-butylaluminum
bis(di(trimethylsilyl)amide), n-octylaluminum
di(pyridine-2-methoxide), bis(n-octadecyl)i-butylaluminum,
i-butylaluminum bis(di(n-pentyl)amide), n-octylaluminum
bis(2,6-di-t-butylphenoxide), n-octylaluminum
di(ethyl(1-naphthyl)amide), ethylaluminum
bis(t-butyldimethylsiloxide), ethylaluminum
di(bis(trimethylsilyl)amide), ethylaluminum
bis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminum
bis(2,3,6,7-dibenzo-1-azacycloheptaneamide), n-octylaluminum
bis(dimethyl(t-butyl)siloxide, ethylzinc (2,6-diphenylphenoxide),
and ethylzinc (t-butoxide). By "exclude the use of" and
"substantially free of" is meant that, while there is the potential
that small amounts of chain shuttling agent may be present as an
impurity in the polymerization process, no chain shuttling agent is
deliberately added to the reactor or reactors before or during the
polymerization process. In one or more embodiments, the
concentration of shuttling agent is less than about 1000 ppm, or
less than about 750 ppm, or less than about 500 ppm, or less than
about 250 ppm, or less than about 100 ppm.
[0073] The catalyst systems described above are suitable for use in
a solution, bulk, gas, or slurry polymerization process or a
combination thereof, preferably solution phase or bulk phase
polymerization process. Preferably, the process is a continuous
process. By "continuous", it is meant a system that operates
without interruption or cessation. For example, a continuous
process to produce a polymer would be one where the reactants are
continually introduced into one or more reactors and polymer
product is continually withdrawn.
[0074] One or more reactors in series or in parallel may be used.
Catalyst precursor and activator may be delivered as a solution or
slurry, either separately to the reactor, activated in-line just
prior to the reactor, or preactivated and pumped as an activated
solution or slurry to the reactor. A preferred operation is two
solutions, for example, one catalyst precursor solution and one
activator solution, activated in-line. Methods to introduce
multiple catalysts into reactors are further described in U.S. Pat.
No. 6,399,722, and PCT Publication No. WO 01/30862A1. While these
references may emphasize gas phase reactors, the techniques
described are equally applicable to other types of reactors,
including continuous stirred tank reactors, slurry loop reactors,
and the like. Polymerizations are carried out in either single
reactor operation, in which monomer, comonomers,
catalyst/activator, scavenger, and optional modifiers are added
continuously to a single reactor or in series reactor operation, in
which the above components are added to each of two or more
reactors connected in series. The catalyst compounds can be added
to the first reactor in the series. The catalyst component may also
be added to both reactors, with one component being added to first
reaction and another component to other reactors.
[0075] Preferably, the polymerization processes using activators of
formula (1) or (2) in combination with a transition metal compound,
preferably a metallocene, are solution processes, where
polymerization is conducted at a temperature of at least about
50.degree. C., or at least about 60.degree. C., or at least about
70.degree. C., or at least about 80.degree. C., or at least about
90.degree. C.
[0076] Preferably, the polymerization processes using activators of
formula (1) and/or (2) in combination with a metallocene as
described above are run with a monomer conversion of from 5 to 95%,
or from 5 to 90%, or from 5 to 85%, or from 5 to 80%, or from 5 to
75%, or from 5 to 70%, all percentages based on a theoretically
possible 100% conversion. The conversion is calculated on a weight
basis (the actual amount (weight in gram) polymer obtained, divided
through the theoretically possible amount (again weight in gram) of
polymer if all monomer was converted into polymer). As an example,
as propylene has a density of 0.52 g/mL, if 100 mL propylene
monomer is fed into the reactor, theoretically 52 g polypropylene
could be obtained (assuming a theoretical 100% conversion). The %
conversion achieved in a particular polypropylene reaction run with
100 mL of propylene is feed is therefore calculated as follows:
conversion [%]=(actual weight (g) polypropylene recovered/52
g).times.100%. So, for example, if 5.2 g of polymer is recovered,
the conversion would be 10%.
Lubricant Compositions and Concentrates
[0077] Lubricating oil compositions comprising the blocky EP
copolymers described herein and one or more base oils (or
basestocks) are also provided. The basestock can comprise natural
or synthetic oils of lubricating viscosity, whether derived from
hydrocracking, hydrogenation, other refining processes, unrefined
processes, or re-refined processes. The basestock can comprise used
oil. Natural oils include animal oils, vegetable oils, mineral
oils, and mixtures thereof. Synthetic oils include hydrocarbon
oils, silicon-based oils, and liquid esters of
phosphorus-containing acids. Synthetic oils may be produced by
Fischer-Tropsch gas-to-liquid synthetic procedures as well as other
gas-to-liquid procedures.
[0078] The basestock may comprise a polyalphaolefin (PAO) including
a PAO-2, PAO-4, PAO-5, PAO-6, PAO-7 or PAO-8 (the numerical value
relating to Kinematic Viscosity at 100.degree. C. (ASTM D 445)).
Preferably, the polyalphaolefin is prepared from dodecene and/or
decene. Generally, polyalphaolefins suitable as oils of lubricating
viscosity have a viscosity less than that of a PAO-20 or PAO-30
oil.
[0079] In one or more embodiments, the basestock can be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines. For example, the basestock can
comprise an API Group I, II, III, IV, or V oil or mixtures
thereof.
[0080] In one or more embodiments, the basestock may include oils
or blends thereof that are conventionally employed as crankcase
lubricating oils. For example, suitable basestocks may include
crankcase lubricating oils for spark-ignited and
compression-ignited internal combustion engines, such as automobile
and truck engines, marine and railroad diesel engines, and the
like. Suitable basestocks may also include those oils
conventionally employed in and/or adapted for use as power
transmitting fluids such as automatic transmission fluids, tractor
fluids, universal tractor fluids and hydraulic fluids, heavy duty
hydraulic fluids, power steering fluids, and the like. Suitable
basestocks may also comprise gear lubricants, industrial oils, pump
oils and other lubricating oils.
[0081] The basestock can include not only hydrocarbon oils derived
from petroleum, but also synthetic lubricating oils such as esters
of dibasic acids; complex esters made by esterification of
monobasic acids, polyglycols, dibasic acids and alcohols;
polyolefin oils, etc. Thus, the lubricating oil compositions
described can be suitably incorporated into synthetic base oil
basestocks such as alkyl esters of dicarboxylic acids, polyglycols
and alcohols; polyalphaolefins; polybutenes; alkyl benzenes;
organic esters of phosphoric acids; polysilicone oils; etc. The
lubricating oil composition can also be utilized in a concentrate
form, such as from 1 wt. % to 49 wt. % in oil, e.g., mineral
lubricating oil, for ease of handling.
[0082] The lubricant compositions may include a basestock and one
or more blocky EP copolymers as described herein. The lubricant
compositions may further optionally comprise a pour point
depressant.
[0083] The lubricant compositions may have a thickening efficiency
(TE) greater than or equal to about 1.0, or 1.5, or 1.7, or 1.9, or
2.0, or 2.1, or 2.2. The lubricant compositions may have a TE less
than or equal to about 4.0, or 3.5, or 3.3, or 3.1, or 3.0, or
2.8.
[0084] The lubricant compositions may have a shear stability index
(SSI) greater than or equal to about 7.5%, or 10.0%, or 12.5%, or
15%, or 17.5%, or 20%. The lubricant compositions may have an SSI
less than or equal to about 32.5%, or 30%, or 27.5%, or 25%, or
22.5%. Alternatively, the lubricant compositions may have an SSI
greater than or equal to about 20%, or 22%, or 24%, or 25%, or 26%,
or 27%, or 28%, or 29%, or 30%.
[0085] The lubricant compositions may have a complex viscosity at
-35.degree. C. of less than 500, or less than 450, or less than
300, or less than 100, or less than 50, or less 20, or less than 10
centistokes (cSt).
[0086] The compositions can have a Mini Rotary Viscometer (MRV)
viscosity at -35.degree. C. in a 10W-50 formulation of less than
60,000 cps according to ASTM 1678.
[0087] The compositions may have any combination of desired
properties. For example, an exemplary lubricant composition may
have a thickening efficiency greater than about 1.0 or greater than
about 2.0, a shear stability index of less than 55 or less than 35
or less than 25, a complex viscosity at -35.degree. C. of less than
500 cSt or less than 300 cSt or less than 50 cSt, and/or a Mini
Rotary Viscometer (MRV) viscosity at -35.degree. C. in a 10W-50
formulation of less than about 60,000 cps according to ASTM
1678.
[0088] The lubricant compositions may comprise less than about 3.0
wt. %, or about 2.5 wt. %, or about 1.5 wt. %, or about 1.0 wt. %
or about 0.5 wt. % of one or more blocky EP copolymers as described
herein, based upon the weight of the composition. In some
embodiments, the amount of the EP copolymer in the lubricant
composition can range from a low of about 0.25 wt. %, 0.5 wt. %,
0.75 wt. %, 1.0 wt. %, or about 1.25 wt. % to a high of about 1.75
wt. %, 2.0 wt. %, 2.25 wt. %, 2.5 wt. %, 2.75 wt. %, or 3.0 wt. %,
based upon the weight of the composition.
Oil Additives
[0089] The lubricant compositions can optionally contain one or
more conventional additives, such as, for example, pour point
depressants, antiwear agents, antioxidants, other viscosity-index
improvers, dispersants, corrosion inhibitors, anti-foaming agents,
detergents, rust inhibitors, friction modifiers, and the like.
[0090] Corrosion inhibitors, also known as anti-corrosive agents,
reduce the degradation of the metallic parts contacted by the
lubricant composition. Illustrative corrosion inhibitors include
phosphosulfurized hydrocarbons and the products obtained by
reaction of a phosphosulfurized hydrocarbon with an alkaline earth
metal oxide or hydroxide, preferably in the presence of an
alkylated phenol or of an alkylphenol thioester, and also
preferably in the presence of carbon dioxide. Phosphosulfurized
hydrocarbons are prepared by reacting a suitable hydrocarbon such
as a terpene, a heavy petroleum fraction of a C.sub.2 to C.sub.6
olefin polymer such as polyisobutylene, with from 5 to 30 wt. % of
a sulfide of phosphorus for 1/2 to 15 hours, at a temperature in
the range of 66.degree. C. to 316.degree. C. Neutralization of the
phosphosulfurized hydrocarbon may be effected in the manner known
by those skilled in the art.
[0091] Oxidation inhibitors, or antioxidants, reduce the tendency
of mineral oils to deteriorate in service, as evidenced by the
products of oxidation such as sludge and varnish-like deposits on
the metal surfaces, and by viscosity growth. Such oxidation
inhibitors include alkaline earth metal salts of
alkylphenolthioesters having C.sub.5 to C.sub.12 alkyl side chains,
e.g., calcium nonylphenate sulfide, barium octylphenate sulfide,
dioctylphenylamine, phenylalphanaphthylamine, phosphosulfurized or
sulfurized hydrocarbons, etc. Other oxidation inhibitors or
antioxidants useful in this invention include oil-soluble copper
compounds, such as described in U.S. Pat. No. 5,068,047.
[0092] Friction modifiers serve to impart the proper friction
characteristics to lubricating oil compositions such as automatic
transmission fluids. Representative examples of suitable friction
modifiers are described in U.S. Pat. No. 3,933,659, which describes
fatty acid esters and amides; U.S. Pat. No. 4,176,074 which
describes molybdenum complexes of polyisobutenyl succinic
anhydride-amino alkanols; U.S. Pat. No. 4,105,571 which describes
glycerol esters of dimerized fatty acids; U.S. Pat. No. 3,779,928
which describes alkane phosphonic acid salts; U.S. Pat. No.
3,778,375 which describes reaction products of a phosphonate with
an oleamide; U.S. Pat. No. 3,852,205 which describes
S-carboxyalkylene hydrocarbyl succinimide, S-carboxyalkylene
hydrocarbyl succinamic acid and mixtures thereof; U.S. Pat. No.
3,879,306 which describes N(hydroxyalkyl)alkenyl-succinamic acids
or succinimides; U.S. Pat. No. 3,932,290 which describes reaction
products of di-(lower alkyl)phosphites and epoxides; and U.S. Pat.
No. 4,028,258 which describes the alkylene oxide adduct of
phosphosulfurized N-(hydroxyalkyl)alkenyl succinimides. Preferred
friction modifiers are succinate esters, or metal salts thereof, of
hydrocarbyl substituted succinic acids or anhydrides and
thiobis-alkanols such as described in U.S. Pat. No. 4,344,853.
[0093] Dispersants maintain oil insolubles, resulting from
oxidation during use, in suspension in the fluid, thus preventing
sludge flocculation and precipitation or deposition on metal parts.
Suitable dispersants include high molecular weight N-substituted
alkenyl succinimides, the reaction product of oil-soluble
polyisobutylene succinic anhydride with ethylene amines such as
tetraethylene pentamine and borated salts thereof. High molecular
weight esters (resulting from the esterification of olefin
substituted succinic acids with mono or polyhydric aliphatic
alcohols) or Mannich bases from high molecular weight alkylated
phenols (resulting from the condensation of a high molecular weight
alkylsubstituted phenol, an alkylene polyamine and an aldehyde such
as formaldehyde) are also useful as dispersants.
[0094] Pour point depressants, otherwise known as lube oil flow
improvers, lower the temperature at which the fluid will flow or
can be poured. Any suitable pour point depressant known in the art
can be used. For example, suitable pour point depressants include,
but are not limited to, one or more C.sub.8 to C.sub.18
dialkylfumarate vinyl acetate copolymers, polymethyl methacrylates,
alkylmethacrylates and wax naphthalene.
[0095] Foam control can be provided by any one or more
anti-foamants. Suitable anti-foamants include polysiloxanes, such
as silicone oils and polydimethyl siloxane.
[0096] Anti-wear agents reduce wear of metal parts. Representatives
of conventional antiwear agents are zinc dialkyldithiophosphate and
zinc diaryldithiosphate, which also serves as an antioxidant.
[0097] Detergents and metal rust inhibitors include the metal salts
of sulphonic acids, alkyl phenols, sulfurized alkyl phenols, alkyl
salicylates, naphthenates and other oil soluble mono- and
dicarboxylic acids. Highly basic (e.g., overbased) metal sales,
such as highly basic alkaline earth metal sulfonates (especially Ca
and Mg salts) are frequently used as detergents.
[0098] Compositions containing these conventional additives can be
blended with the basestock in amounts effective to provide their
normal attendant function. Thus, typical formulations can include,
in amounts by weight, a viscosity index (VI) improver (from about
0.01% to about 12%); a corrosion inhibitor (from about 0.01% to
about 5%); an oxidation inhibitor (from about 0.01% to about 5%);
depressant (from about 0.01% to about 5%); an anti-foaming agent
(from about 0.001% to about 3%); an anti-wear agent (from about
0.001% to about 5%); a friction modifier (from about 0.01% to about
5%); a detergent/rust inhibitor (from about 0.01 to about 10%); and
a base oil, based upon the weight of the formulation.
[0099] When other additives are used, it may be desirable, although
not necessary, to prepare additive concentrates that include
concentrated solutions or dispersions of the VI improver (in
concentrated amounts), together with one or more of the other
additives. Such a concentrate is typically referred to as an
"additive package", whereby several additives can be added
simultaneously to the basestock to form a lubrication oil
composition. Dissolution of the additive concentrate into the
lubrication oil can be facilitated by solvents and by mixing
accompanied with mild heating, but this is not essential. The
additive package can be formulated to contain the VI improver and
optional additional additives in proper amounts to provide the
desired concentration in the final formulation when the additive
package is combined with a predetermined amount of base oil. For
example, the VI improver may be present in a lubricant concentrate
composition or additive package in an amount from about 2.5 to 25
wt. %, or about 5 to 20 wt. %, or about 7.5 to 15 wt. %, or about
10 to 12.5 wt. %, based on the total weight of the lubricant
concentrate.
Blending with Basestock Oils
[0100] Conventional blending methods are described in U.S. Pat. No.
4,464,493, which is incorporated by reference herein. Conventional
processes include passing the polymer through an extruder at
elevated temperature for degradation of the polymer and circulating
hot oil across the die face of the extruder while reducing the
degraded polymer to particle size upon issuance from the extruder
and into the hot oil. The pelletized, solid EP copolymers of the
present invention, as described above, can be added by blending
directly with the base oil. The solid copolymers can be dissolved
in the basestock without the need for additional shearing and
degradation processes.
[0101] The EP copolymers may be soluble at room temperature in lube
oils at from about 7.5 to about 15 wt. %, in order to prepare a
rheology modifier concentrate. Such concentrates, including
eventually an additional additive package including the typical
additives used in lube oil applications as described above, are
generally further diluted to the final concentration (usually
around 1 to 2%) by multi-grade lube oil producers. In this case,
the concentrate will be a pourable homogeneous solid free
liquid.
[0102] The invention may be further described with reference to the
following embodiments.
[0103] Embodiment A: A lubricant composition comprising an oil
basestock and from about 0.5 to about 2.5 wt. %, based on the total
weight of the lubricant composition, of copolymer of propylene and
ethylene, wherein the copolymer comprises from about 50 to about 95
wt. % ethylene, the copolymer has a melting point greater than
about 90.degree. C., and less than about 5 wt. % of the copolymer,
based upon the total weight of the copolymer, is soluble in xylene
or ortho-dichlorobenzene.
[0104] Embodiment B: The lubricant composition of Embodiment A,
wherein the copolymer comprises from about 65 to about 90 wt. %
ethylene.
[0105] Embodiment C: The lubricant composition of any of
Embodiments A through B, wherein the copolymer has a melting point
greater than about 100.degree. C.
[0106] Embodiment D: The lubricant composition of any of
Embodiments A through C, wherein the melting point of the soluble
fraction of the copolymer is greater than about 100.degree. C.
[0107] Embodiment E: The lubricant composition of any of
Embodiments A through D, wherein the lubricant composition has a
thickening efficiency from about 1.5 to about 3.5.
[0108] Embodiment F: The lubricant composition of any of
Embodiments A through E, wherein the lubricant composition has a
shear stability index from about 15% to about 25%.
[0109] Embodiment G: The lubricant composition of any of
Embodiments A through E, wherein the lubricant composition has a
shear stability index greater than or equal to about 24%.
[0110] Embodiment H. The lubricant composition of any of
Embodiments A through G, wherein the copolymer is not synthesized
in the presence of a chain shuttling agent.
[0111] Embodiment I: A lubricant composition comprising an oil
basestock and from about 7.5 to about 15.0 wt. %, based on the
total weight of the lubricant concentrate, of a copolymer of
propylene and ethylene, wherein the copolymer comprises from about
50 to about 95 wt. % ethylene, the copolymer has a melting point
greater than about 90.degree. C., and less than about 5 wt. % of
the copolymer, based upon the total weight of the copolymer, is
soluble in xylene or ortho-dichlorobenzene.
[0112] Embodiment J: The lubricant composition of Embodiment I,
wherein the copolymer comprises from about 65 to about 90 wt. %
ethylene.
[0113] Embodiment K: The lubricant composition of any of
Embodiments I through J, wherein the copolymer has a melting point
greater than about 100.degree. C.
[0114] Embodiment L: The lubricant composition of any of
Embodiments I through K, wherein the melting point of the soluble
fraction of the copolymer is greater than about 100.degree. C.
[0115] Embodiment M: The lubricant composition of any of
Embodiments I through L, wherein the copolymer is not synthesized
in the presence of a chain shuttling agent.
[0116] Embodiment N: The lubricant composition of any of
Embodiments I through M, wherein the oil basestock comprises one or
more oils and a pour point depressant.
[0117] Embodiment O: The lubricant composition of any of
Embodiments I through N, wherein the lubricant composition has a
thickening efficiency from about 1.5 to about 3.5.
[0118] Embodiment P: The lubricant composition of any of
Embodiments I through O, wherein the lubricant composition has a
shear stability index from about 15% to about 25%.
[0119] Embodiment Q: The lubricant composition of any of
Embodiments I through O, wherein the lubricant composition has a
shear stability index greater than or equal to about 24%.
[0120] Embodiment R. A process for making a lubricant composition
comprising: combining (a) an oil basestock, and (b) from about 0.5
to about 2.5 wt. %, based on the total weight of the lubricant
composition, of a copolymer of propylene and ethylene, wherein the
copolymer comprises from about 50 to about 95 wt. % ethylene, the
copolymer has a melting point greater than about 90.degree. C., and
less than about 5 wt. % of the copolymer, based upon the total
weight of the copolymer, is soluble in xylene or
ortho-dichlorobenzene; preferably where the copolymer is prepared
by: [0121] polymerizing propylene and ethylene in a solution
process and in the presence of a catalyst system comprising a
catalyst and an activator to form a copolymer of propylene and
ethylene; wherein the catalyst comprises a metallocene compound,
the activator comprises a cationic component and an anionic
component; wherein the cationic component of the activator
corresponds to the formula:
[0121] [R.sup.1R.sup.2R.sup.3NH].sup.+, i. [0122] where R.sup.1 and
R.sup.2 are together a --(CH.sub.2).sub.a-- group, where a is 3, 4,
5, or 6 and R.sup.1 and R.sup.2 form a 4-, 5-, 6-, or 7-membered
non-aromatic ring together with the nitrogen atom to which one or
more aromatic or heteroaromatic rings may optionally be fused via
adjacent ring carbon atoms, and R.sup.3 is a C.sub.1-C.sub.5 alkyl
group, or
[0122] [R.sub.3NH].sup.+, ii. [0123] where all R are identical and
are C.sub.1-C.sub.3 alkyl groups; and [0124] wherein the anionic
component of the activator corresponds to the formula
[B(R.sup.4).sub.4].sup.-, where R.sup.4 is an aryl group or a
substituted aryl group having one or more substituents, wherein the
one or more substituents are identical or different and are
selected from alkyl, aryl, halogenated aryl, or haloalkylaryl
groups or a hydrogen atom.
[0125] Embodiment S. The process of Embodiment R, wherein the
copolymer is prepared in the absence of a chain shuttling
agent.
[0126] Embodiment T. The process of any of Embodiments R through S,
wherein the copolymer comprises from about 65 to about 90 wt. %
ethylene.
[0127] Embodiment U. The process of any of Embodiments R through T,
wherein less than about 5 wt. % of the copolymer, based upon the
total weight of the copolymer, is soluble in xylene or
ortho-dichlorobenzene.
[0128] Embodiment V. The process of any of Embodiments R through U,
wherein the metallocene compound is a dialkylsilyl-bridged
bis(indenyl)metallocene.
[0129] Embodiment W. The process of any of Embodiments R through V,
wherein the cationic component of the activator is selected from
N-methylpyrrolidinium, N-methylpiperidinium, trimethylammonium, or
triethylammonium; and the anionic component of the activator is
selected from tetrakis(pentafluorophenyl)borate or
tetrakis(heptafluorophenyl)borate.
[0130] Embodiment X. The process of any of Embodiments R through W,
where from about 0.5 to about 2.5 wt. % of the copolymer, based on
the total weight of the lubricant composition, is combined with the
oil basestock.
[0131] Embodiment Y. The process of any of Embodiments R through W,
where from about 7.5 to about 15.0 wt. % of the copolymer, based on
the total weight of the lubricant composition, is combined with the
oil basestock.
Examples
Preparation and Properties of Ethylene-Rich Copolymers
[0132] Five ethylene-propylene copolymers were prepared using a
catalyst system comprising a dimethylsilyl bis(indenyl)hafnium
dimethyl transition metal compound and a trimethyl anilinium
tetrakis(pentafluorophenyl)borate activator. The copolymers have
ethylene contents between about 75 and about 85 wt. %. Inventive
copolymers are identified in Table 1, below, as polymers 1 through
5. Five comparative copolymers, prepared using a chain shuttling
agent, diethyl zinc, are also listed in Table 1 and are identified
as polymers C1 through C5. Properties of the comparative polymers
are taken from PCT Publication No. WO2009/012216 (Table 2).
Representative properties for the inventive and comparative
polymers, including ethylene contents, melting temperatures, and
molecular weight data, are given in Table 1.
TABLE-US-00001 TABLE 1 Amorphous Second High T Mn, Mw, Mw/Mn,
Sample C.sub.2, Tm, .degree. C. Fraction, % Peak, .degree. C. Peak,
.degree. C. g/mol g/mol g/mol No. wt. % (DSC) (TREF) (TREF) (TREF)
(GPC) (GPC) (GPC) 1 77.1 114.4 57.1 77.6 81.7 8617 52572 6.10 2
81.9 117.8 29 74.5 88 14223 58027 4.08 3 75.6 115.6 62 76.2 87
21517 75976 3.50 4 80.4 117.1 -- -- -- 20775 61843 2.98 5 85.4
119.5 -- -- -- 25840 98553 3.81 C1 71.4 73.7 -- -- -- 70800 157600
2.2 C2 71.5 38.8 -- -- -- 48040 92530 1.9 C3 71.2 37.0 -- -- --
66140 133700 2.0 C4 69.0 42.0 -- -- -- 65770 153600 2.3 C5 69.6
41.4 -- -- -- 63940 145800 2.3
[0133] Inventive polymer 2, having an ethylene content of 81.9 wt.
%, was fractionated using ortho-dichlorobenzene (ODCB) according to
the fractionation procedure described previously. Three fractions
were obtained. Properties of each of the fractions are given in
Table 2, below.
TABLE-US-00002 TABLE 2 Fraction Solvent Fraction Wt. Cumulative
C.sub.2, Tm, No. Temp, .degree. C. (mass/g) % Wt. % wt. % .degree.
C. 1 0.0 33.0 8.1 8.1 71.7 110.25 2 10.0 92.0 22.5 30.6 74.5 117.13
3 130.0 282.0 69.1 99.8 80.4 122.14
[0134] As shown in Table 2, all three fractions obtained from
polymer 2 show at least one melting temperature above 110.degree.
C., which indicates that all of the fractions comprise long
ethylene sequences. These melting temperatures are at least about
20.degree. C. higher than those of random ethylene-propylene
copolymers having similar ethylene contents. Further, the melting
temperatures are also at least about 20.degree. C. higher than
those of blocky ethylene-propylene copolymers prepared using a
chain shuttling agent, as reported in PCT Publication No.
WO2009/012216. These properties are illustrated graphically in FIG.
1, which shows melting temperature versus comonomer content for the
polymers in Tables 1 and 2.
Preparation of Lubricant Compositions (Prophetic)
[0135] EP copolymers corresponding to Polymers 1 through 5 above
are dissolved in STS ENJ102 oil (available from ExxonMobil Chemical
Company) at a concentration of 1.5 wt. %, so as to resemble
commercially available lubricant formulations.
TABLE-US-00003 TABLE 3 VI Improver VI Improver Wt. % Polymer 1 1.5
Polymer 2 1.5 Polymer 3 1.5 Polymer 4 1.5 Polymer 5 1.5 Paratone
8900 1.5
Preparation of Lubricant Concentrate Compositions (Prophetic)
[0136] Lubricant concentrate compositions are prepared by
dissolving 11.3 wt. % of each of Polymers 1 through 5 in an SAE
10W40 base oil comprising 14.8 wt. % of a detergent inhibitor
package, 0.3 wt. % of a pour point depressant, 58 wt. % Chevron 100
oil, and 42 wt. % Chevron 220 oil. Chevron 100 and Chevron 220 are
both available from Chevron Corporation.
[0137] Certain embodiments and features have been described herein
using a set of numerical upper limits and a set of numerical lower
limits. It should be appreciated that ranges from any lower limit
to any upper limit are contemplated unless otherwise indicated.
Certain lower limits, upper limits and ranges appear in one or more
claims below. All numerical values are "about" or "approximately"
the indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0138] Various terms have been defined above. To the extent a term
used in a claim is not defined above, it should be given the
broadest definition persons in the pertinent art have given that
term as reflected in at least one printed publication or issued
patent. Furthermore, any patents, test procedures, or other
documents cited in this application are fully incorporated by
reference to the extent such disclosure is not inconsistent with
this application and for all jurisdictions in which such
incorporation is permitted.
[0139] As is apparent from the foregoing general description and
the specific embodiments, while forms of the invention have been
illustrated and described, various modifications can be made
without departing from the spirit and scope of the invention.
Accordingly, it is not intended that the invention be limited
thereby.
* * * * *