U.S. patent application number 17/128693 was filed with the patent office on 2021-06-24 for lubricant composition comprising an antioxidant composition.
The applicant listed for this patent is SI Group, Inc.. Invention is credited to Tom Tang.
Application Number | 20210189280 17/128693 |
Document ID | / |
Family ID | 1000005314593 |
Filed Date | 2021-06-24 |
United States Patent
Application |
20210189280 |
Kind Code |
A1 |
Tang; Tom |
June 24, 2021 |
Lubricant Composition Comprising an Antioxidant Composition
Abstract
A lubricant composition is disclosed comprising an antioxidant
composition and a lubricating oil. The antioxidant composition
comprises a phenolic antioxidant having the following structure (I)
##STR00001## and a phosphite antioxidant having the following
structure (II) ##STR00002## wherein, A is a direct bond or an
alkylene; X is --C(O)O--, --OC(O)--, --C(O)N(R.sub.7)--,
--N(R.sub.7)C(O)--, --C(O)--, --N(R.sub.7)--, --O--, or --S--;
R.sub.1 and R.sub.2 are each independently a C.sub.1-C.sub.10
alkyl, a C.sub.2-C.sub.10 alkenyl, a C.sub.2-C.sub.10 alkynyl, or a
C.sub.3-C.sub.12 aryl; R.sub.3 includes a C.sub.1-C.sub.80 alkyl, a
C.sub.2-C.sub.80 alkenyl, a C.sub.2-C.sub.80 alkynyl, or a
C.sub.3-C.sub.12 aryl; R.sub.4, R.sub.5, and R.sub.6 are each
independently hydrogen, alkyl, alkenyl, alkynyl, or aryl provided
that at least one of R.sub.4, R.sub.5, and R.sub.6 is not hydrogen;
R.sub.7 is H or an alkyl; and m, n, and o are each independently
from 1 to 3.
Inventors: |
Tang; Tom; (Chapin,
SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SI Group, Inc. |
Schenectady |
NY |
US |
|
|
Family ID: |
1000005314593 |
Appl. No.: |
17/128693 |
Filed: |
December 21, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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62988061 |
Mar 11, 2020 |
|
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|
62951284 |
Dec 20, 2019 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10M 141/10 20130101;
C10M 141/06 20130101; C10M 2207/023 20130101; C10M 2223/049
20130101; C10M 141/02 20130101; C10M 169/04 20130101; C10M 2215/042
20130101; C10N 2030/10 20130101 |
International
Class: |
C10M 141/10 20060101
C10M141/10; C10M 141/02 20060101 C10M141/02; C10M 141/06 20060101
C10M141/06; C10M 169/04 20060101 C10M169/04 |
Claims
1-37. (canceled)
38. A lubricant composition comprising: an antioxidant composition
comprising a phenolic antioxidant having the following structure
(I) ##STR00011## and a phosphite antioxidant having the following
structure (II) ##STR00012## wherein, A is a direct bond or an
alkylene; X is --C(O)O--, --OC(O)--, --C(O)N(R.sub.7)--,
--N(R.sub.7)C(O)--, --C(O)--, --N(R.sub.7)--, --O--, or --S--;
R.sub.1 and R.sub.2 are each independently a C.sub.1-C.sub.10
alkyl, a C.sub.2-C.sub.10 alkenyl, a C.sub.2-C.sub.10 alkynyl, or a
C.sub.3-C.sub.12 aryl; R.sub.3 includes a C.sub.1-C.sub.80 alkyl, a
C.sub.2-C.sub.80 alkenyl, a C.sub.2-C.sub.80 alkynyl, or a
C.sub.3-C.sub.12 aryl; R.sub.4, R.sub.5, and R.sub.6 are each
independently hydrogen, alkyl, alkenyl, alkynyl, or aryl provided
that at least one of R.sub.4, R.sub.5, and R.sub.6 is not hydrogen;
R.sub.7 is H or an alkyl; and m, n, and o are each independently
from 1 to 3; and a lubricating oil.
39. The lubricant composition of claim 38, wherein the weight ratio
of the phenolic antioxidant to the phosphite antioxidant is from
0.1 to 10.
40. The lubricant composition of claim 38, wherein the phenolic
antioxidant is present in the lubricant composition in an amount of
from 0.01% by weight to 5% by weight.
41. The lubricant composition of claim 38, wherein the phosphite
antioxidant is present in the lubricant composition in an amount of
from 0.01% by weight to 5% by weight.
42. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a standard RPVOT oxidation induction time of
150 minutes or more as determined according to ASTM D2272-14a and
at a temperature of 150.degree. C.
43. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a standard RPVOT oxidation induction time as
determined according to ASTM D2272-14a at a temperature of
150.degree. C. of at least 20% greater than an expected standard
RPVOT oxidation induction time.
44. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a dry RPVOT oxidation induction time of 200
minutes or more as determined according to a modified ASTM
D2272-14a and at a temperature of 150.degree. C.
45. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a dry RPVOT oxidation induction time as
determined according to a modified ASTM D2272-14a at a temperature
of 150.degree. C. of at least 20% greater than an expected dry
RPVOT oxidation induction time.
46. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a PDSC oxidation induction time of 20 minutes
or more as determined at a temperature of 160.degree. C.
47. The lubricant composition of claim 38, wherein the lubricant
composition exhibits a TEOST 33C deposit of 50 mg or less as
determined according to ASTM D6335-16 and a temperature change on a
depositor rod from 200.degree. C. to 480.degree. C.
48. The lubricant composition of claim 38, wherein R.sub.1 and
R.sub.2 are each a C.sub.1-C.sub.5 alkyl.
49. The lubricant composition of claim 38, wherein A is a
C.sub.1-C.sub.8 alkylene.
50. The lubricant composition of claim 38, wherein X is
--C(O)O--.
51. The lubricant composition of claim 38, wherein R.sub.3 includes
a C.sub.10-C.sub.80 alkyl.
52. The lubricant composition of claim 38, wherein R.sub.3 includes
a C.sub.10-C.sub.20 alkyl.
53. The lubricant composition of claim 38, wherein R.sub.4,
R.sub.5, and R.sub.6 are each alkyl.
54. The lubricant composition of claim 38, wherein R.sub.4,
R.sub.5, and R.sub.6 are each independently a C.sub.1-C.sub.10
alkyl.
55. The lubricant composition of claim 38, wherein m, n, and o are
1 or m, n, and o are 2.
56. The lubricant composition of claim 38, wherein two of m, n, and
o are 1 and one of m, n, and o is 2 or one of m, n, and o is 1 and
two of m, n, and o are 2
57. The lubricant composition of claim 38, wherein the lubricant
composition further comprises an alkanolamine.
58. The lubricant composition of claim 38, wherein the lubricant
composition further comprises a triisopropanolamine n an amount of
about 5 wt. % or less.
Description
RELATED APPLICATIONS
[0001] This application claims filing benefit of U.S. Provisional
Patent Application No. 62/951,284 having a filing date of Dec. 20,
2019 and U.S. Provisional Patent Application No. 62/988,061 having
a filing date of Mar. 11, 2020, both of which are hereby
incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] Lubricant compositions are utilized in a variety of
applications. During use and even prior to use, these lubricant
compositions are exposed to heat and oxygen which can result in
oxidation of the lubricant composition. Such oxidation can result
in decreased performance and can also potentially damage the
machinery on which the composition is utilized. Accordingly, the
lubricant composition has a decreased service life thereby
requiring replacement sooner than desired. In order to prevent the
oxidation or extend the oxidation induction, various types of
antioxidants are employed. However, certain available antioxidants
may not perform as well as desired. For instance, they may not
prevent oxidation or extend the oxidation induction as desired
thereby resulting in oxidation of the lubricant composition earlier
than desired.
[0003] As such, a need continues to exist for a lubricant
composition having improved antioxidation performance.
SUMMARY OF THE INVENTION
[0004] In accordance with one embodiment of the present invention,
a lubricant composition is disclosed. The lubricant composition
comprises an antioxidant composition and a lubricating oil. The
antioxidant composition comprises a phenolic antioxidant having the
following structure (I)
##STR00003##
and a phosphite antioxidant having the following structure (II)
##STR00004##
wherein,
[0005] A is a direct bond or an alkylene;
[0006] X is --C(O)O--, --OC(O)--, --C(O)N(R.sub.7)--,
--N(R.sub.7)C(O)--, --C(O)--, --N(R.sub.7)--, --O-- or --S--;
[0007] R.sub.1 and R.sub.2 are each independently a
C.sub.1-C.sub.10 alkyl, a C.sub.2-C.sub.10 alkenyl, a
C.sub.2-C.sub.10 alkynyl, or a C.sub.3-C.sub.12 aryl;
[0008] R.sub.3 includes a C.sub.1-C.sub.80 alkyl, a
C.sub.2-C.sub.80 alkenyl, a C.sub.2-C.sub.80 alkynyl, or a
C.sub.3-C.sub.12 aryl;
[0009] R.sub.4, R.sub.5, and R.sub.6 are each independently
hydrogen, alkyl, alkenyl, alkynyl, or aryl provided that at least
one of R.sub.4, R.sub.5, and R.sub.6 is not hydrogen;
[0010] R.sub.7 is H or an alkyl; and
[0011] m, n, and o are each independently from 1 to 3.
[0012] In accordance with another embodiment of the present
invention, a method of forming a lubricant composition is
disclosed. The method comprises combining a lubricating oil with
the aforementioned antioxidant composition.
[0013] Other features and aspects of the present invention are set
forth in greater detail below.
Definitions
[0014] It is to be understood that the terminology used herein is
for the purpose of describing particular embodiments only and is
not intended to limit the scope of the present invention.
[0015] "Alkyl" refers to straight chain, branched chain, or cyclic
monovalent saturated aliphatic hydrocarbyl groups and
"C.sub.q-C.sub.r alkyl" refers to alkyl groups having from q to r
carbon atoms. This term includes, by way of example, straight
chain, branched chain, or cyclic hydrocarbyl groups, such as
methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl,
decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,
hexadecyl, heptadecyl, octadecyl, nonadecyl, icosanyl, henicosanyl,
docosanyl, tricosanyl, tetracosanyl, pentacosanyl, hexacosanyl,
heptacosanyl, octacosanyl, and the like. Alkyl includes a
substituted alkyl or an unsubstituted alkyl. For example, the alkyl
may be substituted (e.g., having from 1 to 5 and, in some
embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the
alkyl may be unsubstituted.
[0016] "Alkylene" refers to a straight chain or branched chain
divalent hydrocarbyl. For example, "C.sub.y-C.sub.z alkylene"
refers to an alkylene group having from y to z carbon atoms. This
term includes, by way of example, straight chain or branched chain
hydrocarbyl groups, such as methylene, ethylene, propylene (e.g.,
n-propylene), butylene (e.g., n-butylene), and the like.
[0017] "Alkenyl" refers to a straight chain or branched chain
monovalent aliphatic hydrocarbyl group having at least 1 site of
vinyl unsaturation (>C.dbd.C<). For example, "C.sub.s-C.sub.t
alkenyl" refers to alkenyl groups having from s to t carbon atoms.
This term includes, by way of example, straight chain or branched
chain hydrocarbyl groups, such as ethenyl, propenyl,
1,3-butadienyl, and the like. Alkenyl includes a substituted
alkenyl or an unsubstituted alkenyl. For example, the alkenyl may
be substituted (e.g., having from 1 to 5 and, in some embodiments,
1 to 3 or 1 to 2 substituents). Alternatively, the alkenyl may be
unsubstituted.
[0018] "Alkynyl" refers to a straight chain or branched chain
monovalent aliphatic hydrocarbyl group having at least one carbon
triple bond. The term "alkynyl" is also meant to include those
hydrocarbyl groups having one triple bond and one double bond. For
example, "C.sub.u-C.sub.v alkynyl" refers to alkynyl groups having
from u to v carbon atoms. This term includes, by way of example,
straight chain or branched chain hydrocarbyl groups, such as
ethynyl, propynyl, and the like. Alkynyl includes a substituted
alkynyl or an unsubstituted alkynyl. For example, the alkynyl may
be substituted (e.g., having from 1 to 5 and, in some embodiments,
1 to 3 or 1 to 2 substituents). Alternatively, the alkynyl may be
unsubstituted.
[0019] "Aryl" refers to an aromatic hydrocarbyl group. For example,
"C.sub.w-C.sub.x aryl" refers to aryl groups having from w to x
carbon atoms. This term includes, by way of example, linear and
branched hydrocarbyl groups, such as phenyl, naphthyl, indenyl,
azulenyl, fluorenyl, anthracenyl, phenanthrenyl,
tetrahydronaphthyl, indanyl, phenanthridinyl and the like. Aryl
includes a substituted aryl or an unsubstituted aryl. For example,
the aryl may be substituted (e.g., having from 1 to 5 and, in some
embodiments, 1 to 3 or 1 to 2 substituents). Alternatively, the
aryl may be unsubstituted.
[0020] It is understood that the above definitions are not intended
to include impermissible substitution patterns (e.g., methyl
substituted with 5 fluoro groups). Such impermissible substitution
patterns are well known to a person skilled in the art.
DETAILED DESCRIPTION
[0021] It is to be understood by one of ordinary skill in the art
that the present discussion is a description of exemplary
embodiments only, and is not intended as limiting the broader
aspects of the present invention.
[0022] Generally speaking, the present invention is directed to a
lubricant composition including a lubricating oil and a specific
antioxidant composition. In particular, the antioxidant composition
comprises at least one phenolic antioxidant and at least one
phosphite antioxidant as defined herein. The present inventors have
discovered that when such an antioxidant composition is utilized,
it can provide a lubricant composition with improved properties. In
particular, the present inventors have discovered that the
antioxidant composition can be utilized to further stabilize a
lubricating oil for a lubricant composition. For instance, the
antioxidant composition may extend the lubricant composition's
oxidation induction time, mitigate the viscosity increase of the
lubricant composition, and/or abate the lubricant composition's
acid number increase.
[0023] For example, the lubricant composition may exhibit improved
oxidation stability as determined according to a standard rotating
pressure vessel oxidation test (RPVOT). In particular, the
lubricant composition may exhibit a standard RPVOT oxidation
induction time of 150 minutes or more, such as 200 minutes or more,
such as 250 minutes or more, such as 275 minutes or more, such as
290 minutes or more, such as 300 minutes or more, such as 325
minutes or more, such as 350 minutes or more. The standard RPVOT
oxidation induction time may be 600 minutes or less, such as 500
minutes or less, such as 450 minutes or less, such as 400 minutes
or less, such as 375 minutes or less, such as 350 minutes or less,
such as 325 minutes or less. In general, the longer the oxidation
induction time, the better the oxidation stability of the oil. The
standard RPVOT oxidation induction time may be determined according
to ASTM D2272-14a and at a temperature of 150.degree. C. In
addition, the actual standard RPVOT oxidation induction time may be
greater than an expected standard RPVOT oxidation induction time as
determined herein. For instance, such actual standard RPVOT
oxidation induction time may be at least 20% greater, such as at
least 30% greater, such as at least 40% greater, such as at least
50% greater, such as at least 60% greater than an expected standard
RPVOT oxidation induction time. Accordingly, by exhibiting a
standard RPVOT oxidation induction time greater than an expected
standard RPVOT oxidation induction time, the antioxidant
composition may demonstrate a synergistic antioxidant activity.
While the aforementioned references the standard RPVOT oxidation
induction time of the lubricant composition, in another embodiment,
such oxidation induction times may be realized for the antioxidant
composition when measured utilizing the lubricating oil as
described in the test method and examples below.
[0024] In addition, the lubricant composition may also exhibit
improved oxidation stability when determined according to a dry
RPVOT without the use of water. For example, the lubricant
composition may exhibit a dry RPVOT oxidation induction time of 200
minutes or more, such as 300 minutes or more, such as 400 minutes
or more, such as 450 minutes or more, such as 500 minutes or more,
such as 550 minutes or more. The dry RPVOT oxidation induction time
may be 1,000 minutes or less, such as 900 minutes or less, such as
800 minutes or less, such as 700 minutes or less, such as 650
minutes or less, such as 600 minutes or less, such as 575 minutes
or less, such as 550 minutes or less, such as 500 minutes or less.
In general, the longer the oxidation induction time, the better the
oxidation stability of the oil. The dry RPVOT oxidation induction
time may be determined according to a modified ASTM D2272-14a and
at a temperature of 150.degree. C. except that the test does not
utilize water (e.g., the 5 g of water as required by the test for
determining the standard RPVOT oxidation induction time). In
addition, the actual dry RPVOT oxidation induction time may be
greater than an expected dry RPVOT oxidation induction time as
determined herein. For instance, such actual dry RPVOT oxidation
induction time may be at least 20% greater, such as at least 30%
greater, such as at least 40% greater, such as at least 50%
greater, such as at least 60% greater, such as at least 70% greater
than an expected dry RPVOT oxidation induction time. Accordingly,
by exhibiting a dry RPVOT oxidation induction time greater than an
expected dry RPVOT oxidation induction time, the antioxidant
composition may demonstrate a synergistic antioxidant activity.
While the aforementioned references the dry RPVOT oxidation
induction time of the lubricant composition, in another embodiment,
such oxidation induction times may be realized for the antioxidant
composition when measured utilizing the lubricating oil as
described in the test method and examples below.
[0025] Also, the lubricant composition may demonstrate improved
oxidation performance when measured according to pressure
differential scanning calorimetry (PDSC). For example, the
lubricant composition may exhibit a PDSC oxidation induction time
of 20 minutes or more, such as 40 minutes or more, such as 50
minutes or more, such as 70 minutes or more, such as 90 minutes or
more, such as 100 minutes or more, such as 120 minutes or more,
such as 140 minutes or more, such as 160 minutes or more. The PDSC
oxidation induction time may be 350 minutes or less, such as 300
minutes or less, such as 250 minutes or less, such as 200 minutes
or less, such as 190 minutes or less, such as 175 minutes or less,
such as 150 minutes or less, such as 130 minutes or less, such as
110 minutes or less, such as 100 minutes or less. In general, the
longer the oxidation induction time, the better the oxidation
stability of the oil. The PDSC oxidation induction time may be
determined at a temperature of 160.degree. C. In addition, the
actual PDSC oxidation induction time may be greater than an
expected PDSC oxidation induction time as determined herein. For
instance, such actual PDSC oxidation induction time may be at least
20% greater, such as at least 30% greater, such as at least 50%
greater, such as at least 70% greater, such as at least 100%
greater, such as at least 150% greater, such as at least 200%
greater than an expected PDSC oxidation induction time.
Accordingly, by exhibiting a PDSC oxidation induction time greater
than an expected PDSC oxidation induction time, the antioxidant
composition may demonstrate a synergistic antioxidant activity.
While the aforementioned references the PDSC oxidation induction
time of the lubricant composition, in another embodiment, such
oxidation induction times may be realized for the antioxidant
composition when measured utilizing the lubricating oil as
described in the test method and examples below.
[0026] In addition, the lubricant composition may demonstrate a
reduced amount of deposits, which can be important in regard to
maintaining the performance of machinery on which the lubricant
composition is utilized. For example, the lubricant composition may
have deposits as demonstrated according to a thermo-oxidation
engine oil simulation test (TEOST 33C) in an amount of 50 mg or
less, such as 40 mg or less, such as 30 mg or less, such as 25 mg
or less, such as 20 mg or less, such as 18 mg or less, such as 15
mg or less, such as 13 mg or less. The TEOST 33C deposit may be
more than 0 mg, such as 1 mg or more, such as 2 mg or more, such as
5 mg or more, such as 8 mg or more, such as 10 mg or more. In
general, the less the amount of deposits obtained, the better the
oxidation stability of the oil. The TEOST 33C deposit may be
determined according to ASTM D6335-16 and a temperature change on a
depositor rod of from 200.degree. C. to 480.degree. C. While the
aforementioned references the TEOST 33C deposit of the lubricant
composition, in another embodiment, such TEOST 33C deposit may be
realized for the antioxidant composition when measured utilizing
the lubricating oil as described in the test method and examples
below.
[0027] Also, with the improvements realized as mentioned above, the
lubricant composition may still demonstrate an acceptable antiwear
performance. In this regard, the antiwear performance may not be
detrimentally affected and in certain instances may even be
improved. In general, the antiwear performance as determined
according to ASTM D4172-18 may indicate the presence of a generally
low wear scar. For instance, the wear scar may be 5 mm or less,
such as 3 mm or less, such as 2 mm or less, such as 1.8 mm or less,
such as 1.5 mm or less, such as 1.3 mm or less, such as 1 mm or
less, such as 0.9 mm or less, such as 0.8 mm or less, such as 0.7
mm or less, such as 0.6 mm or less. The wear scar may be more than
0 mm, such as 0.1 mm or more, such as 0.2 mm or more, such as 0.3
mm or more, such as 0.4 mm or more, such as 0.5 mm or more, such as
0.6 mm or more, such as 0.7 mm or more. In addition, the actual
wear scar may be less than an expected wear scar as determined
herein. For instance, such wear scar may be at least 2% less, such
as at least 5% less, such as at least 10% less, such as at least
15% less, such as at least 20% less, such as at least 25% less,
such as at least 30% less, such as at least 40% less than an
expected wear scar. Accordingly, by exhibiting a wear scar less
than an expected wear scar, the antioxidant composition may
demonstrate a synergistic antioxidant activity. While the
aforementioned references the wear scar of the lubricant
composition, in another embodiment, such wear scar may be realized
for the antioxidant composition when measured utilizing the
lubricating oil as described in the test method and examples
below.
A. Antioxidant Composition
[0028] As indicated above, the antioxidant composition as disclosed
herein provides a lubricating oil and resulting lubricant
composition with improved oxidation stability. In this regard, the
antioxidant composition includes at least one phenolic antioxidant
and at least one phosphite antioxidant as defined herein. The
present inventors have discovered that utilizing such a composition
can improve the performance of the composition and the resulting
lubricating composition. In addition, in certain embodiments, the
respective antioxidants may be provided in certain amounts to
improve such performance.
[0029] For instance, the weight ratio of the phenolic antioxidant
to the phosphite antioxidant may be within a certain range. For
instance, the weight ratio may be about 0.1 or more, such as about
0.2 or more, such as about 0.3 or more, such as about 0.33 or more,
such as about 0.4 or more, such as about 0.5 or more, such as about
0.6 or more, such as about 0.66 or more. The weight ratio may be
about 10 or less, such as about 8 or less, such as about 6 or less,
such as about 4 or less, such as about 3 or less, such as about 2
or less, such as about 1.7 or less, such as about 1.5 or less, such
as about 1.2 or less, such as about 1 or less, such as about 0.9 or
less, such as about 0.75 or less, such as about 0.66 or less, such
as about 0.6 or less, such as about 0.55 or less. In one
embodiment, the molar ratio of the phenolic antioxidant to the
phosphite antioxidant may also be within the aforementioned
ranges.
[0030] The phenolic antioxidant may be present in the antioxidant
composition in an amount of more than 0 wt. %, such as about 5 wt.
% or more, such as about 10 wt. % or more, such as about 20 wt. %
or more, such as about 30 wt. % or more, such as about 40 wt. % or
more, such as about 50 wt. % or more, such as about 60 wt. % or
more, such as about 70 wt. % or more, such as about 80 wt. % or
more. The phenolic antioxidant may be present in the antioxidant
composition in an amount of less than 100 wt. %, such as about 95
wt. % or less, such as about 90 wt. % or less, such as about 80 wt.
% or less, such as about 70 wt. % or less, such as about 60 wt. %
or less, such as about 50 wt. % or less, such as about 40 wt. % or
less, such as about 30 wt. % or less, such as about 20 wt. % or
less.
[0031] The phenolic antioxidant may be present in the lubricating
composition in an amount of about 0.01 wt. % or more, such as about
0.1 wt. % or more, such as about 0.2 wt. % or more, such as about
0.5 wt. % or more, such as about 1 wt. % or more, such as about 1.5
wt. % or more, such as about 2 wt. % or more. The phenolic
antioxidant may be present in the lubricating composition in an
amount of about 10 wt. % or less, such as about 8 wt. % or less,
such as about 6 wt. % or less, such as about 5 wt. % or less, such
as about 4 wt. % or less, such as about 3 wt. % or less, such as
about 2.5 wt. % or less, such as about 2 wt. % or less, such as
about 1.5 wt. % or less, such as about 1 wt. % or less.
[0032] The phosphite antioxidant may be present in the antioxidant
composition in an amount of more than 0 wt. %, such as about 5 wt.
% or more, such as about 10 wt. % or more, such as about 20 wt. %
or more, such as about 30 wt. % or more, such as about 40 wt. % or
more, such as about 50 wt. % or more, such as about 60 wt. % or
more, such as about 70 wt. % or more, such as about 80 wt. % or
more. The phosphite antioxidant may be present in the antioxidant
composition in an amount of less than 100 wt. %, such as about 95
wt. % or less, such as about 90 wt. % or less, such as about 80 wt.
% or less, such as about 70 wt. % or less, such as about 60 wt. %
or less, such as about 50 wt. % or less, such as about 40 wt. % or
less, such as about 30 wt. % or less, such as about 20 wt. % or
less.
[0033] The phosphite antioxidant may be present in the lubricating
composition in an amount of about 0.01 wt. % or more, such as about
0.1 wt. % or more, such as about 0.2 wt. % or more, such as about
0.5 wt. % or more, such as about 1 wt. % or more, such as about 1.5
wt. % or more, such as about 2 wt. % or more. The phosphite
antioxidant may be present in the lubricating composition in an
amount of about 10 wt. % or less, such as about 8 wt. % or less,
such as about 6 wt. % or less, such as about 5 wt. % or less, such
as about 4 wt. % or less, such as about 3 wt. % or less, such as
about 2.5 wt. % or less, such as about 2 wt. % or less, such as
about 1.5 wt. % or less, such as about 1 wt. % or less.
[0034] In one embodiment, the phenolic antioxidant may be present
in an amount greater than the phosphite antioxidant based on
weight. In another embodiment, the phenolic antioxidant may be
present in an amount less than the phosphite antioxidant based on
weight. In a further embodiment, the phenolic antioxidant may be
present in an amount the same as the phosphite antioxidant based on
weight.
[0035] Also, in one embodiment, the antioxidant composition may be
a liquid at ambient conditions (i.e., at atmospheric pressure and a
temperature of 25.degree. C.). By providing such antioxidant
composition as a liquid, it may be easily combined with a
lubricating oil to form the lubricant composition.
[0036] i. Phenolic Antioxidant
[0037] As indicated herein, the antioxidant composition includes at
least one phenolic antioxidant. In this regard, the phenolic
antioxidant may have the following structure (I):
##STR00005##
wherein,
[0038] A is a direct bond or an alkylene;
[0039] X is --C(O)O--, --OC(O)--, --C(O)N(R.sub.7)--,
--N(R.sub.7)C(O)--, --C(O)--, --N(R.sub.7)--, --O-- or --S--;
[0040] R.sub.1 and R.sub.2 are each independently a
C.sub.1-C.sub.10 alkyl, a C.sub.2-C.sub.10 alkenyl, a
C.sub.2-C.sub.10 alkynyl, or a C.sub.3-C.sub.12 aryl;
[0041] R.sub.3 includes a C.sub.1-C.sub.80 alkyl, a
C.sub.2-C.sub.80 alkenyl, a C.sub.2-C.sub.80 alkynyl, or a
C.sub.3-C.sub.12 aryl; and
[0042] R.sub.7 is H or an alkyl.
[0043] As indicated above, "A" is a direct bond or an alkylene. In
one embodiment, "A" is a direct bond such that the carbon in the
ring is bonded directly to "X." In another embodiment, "A" is an
alkylene (i.e., an alkylene bridge) bonded to the carbon in the
ring and "X." For instance, the alkylene may be a C.sub.1-C.sub.8
alkylene, such as a C.sub.1-C.sub.5 alkylene, such as a
C.sub.1-C.sub.3 alkylene, such as a C.sub.1-C.sub.2 alkylene or a
C.sub.2-C.sub.3 alkylene. For instance, the alkylene may be a
methylene, an ethylene, a propylene, a butylene, etc. In one
embodiment, the alkylene may be a methylene. In another embodiment,
the alkylene may be an ethylene. In a further embodiment, the
alkylene may be a propylene. In an even further embodiment, the
alkylene may be a butylene. Also, it should be understood that, in
one embodiment, the alkylene may be a substituted alkylene wherein
the substitution may comprise a C.sub.1-C.sub.20 alkyl, such as a
C.sub.1-C.sub.15 alkyl, such as a C.sub.1-C.sub.10 alkyl, such as a
C.sub.1-C.sub.8 alkyl, such as a C.sub.1-C.sub.4 alkyl.
[0044] As indicated above, "X" is --C(O)O--, --OC(O)--,
--C(O)N(R.sub.7)--, --N(R.sub.7)C(O)--, --C(O)--, --N(R.sub.7)--,
--O--, or --S--. For instance, "X" may be --C(O)O--, --OC(O)--,
--C(O)N(R.sub.7)--, --N(R.sub.7)C(O)--, or --C(O)--. In particular,
"X" may be --C(O)O-- or --OC(O)--. In this regard, in one
embodiment, "X" is --C(O)O--. In another embodiment, "X" is
--OC(O)--. In a further embodiment, "X" is --C(O)N(R.sub.7)--. In
an even further embodiment, "X" is --N(R.sub.7)C(O)--. In another
embodiment, "X" is --C(O)--. In a further embodiment, "X" is
--O--.
[0045] As indicated above, in one embodiment, "X" may be
--C(O)N(R.sub.7)--, --N(R.sub.7)C(O)--, or --N(R.sub.7)--. In this
regard, as also indicated above, R.sub.7 is H or an alkyl. In one
embodiment, R.sub.7 is H. In another embodiment, R.sub.7 is an
alkyl. For instance, the R.sub.7 alkyl may be a C.sub.1-C.sub.30
alkyl, such as a C.sub.1-C.sub.26 alkyl, such as a C.sub.1-C.sub.20
alkyl, such as a C.sub.1-C.sub.14 alkyl, such as a C.sub.1-C.sub.10
alkyl, such as a C.sub.1-C.sub.4 alkyl, such as a C.sub.1-C.sub.3
alkyl, such as a C.sub.1-C.sub.2 alkyl. For instance, the R.sub.7
alkyl may have 1 or more, such as 2 or more, such as 3 or more,
such as 5 or more, such as 10 or more carbon atoms. The R.sub.7
alkyl may have 30 or less, such as 24 or less, such as 20 or less,
such as 18 or less, such as 12 or less, such as 8 or less, such as
6 or less, such as 4 or less, such as 3 or less, such as 2 or less
carbon atoms. In addition, the R.sub.7 alkyl may be a straight
chain, a branched chain, or cyclic. In one embodiment, the R.sub.7
alkyl is a straight chain. In another embodiment, the R alkyl is a
branched chain. In a further embodiment, the R alkyl is cyclic.
[0046] As indicated above, R.sub.1 and R.sub.2 are each
independently a C.sub.1-C.sub.10 alkyl, a C.sub.2-C.sub.10 alkenyl,
a C.sub.2-C.sub.10 alkynyl, or a C.sub.3-C.sub.12 aryl. In one
embodiment, R.sub.1 and R.sub.2 may be different. For instance,
while they may have the same chemical formula, they may be isomers
having a different structure or configuration. In another
embodiment, however, R.sub.1 and R.sub.2 may be the same.
[0047] In one embodiment, at least one of R.sub.1 and R.sub.2 may
be a C.sub.1-C.sub.10 alkyl. For instance, in one embodiment,
R.sub.1 may be a C.sub.1-C.sub.10 alkyl. In another embodiment,
R.sub.2 may be a C.sub.1-C.sub.10 alkyl. In a further embodiment,
R.sub.1 and R.sub.2 may be a C.sub.1-C.sub.10 alkyl. In particular,
the alkyl may be a C.sub.1-C.sub.7 alkyl, such as a C.sub.1-C.sub.6
alkyl, such as a C.sub.1-C.sub.5 alkyl, such as a C.sub.1-C.sub.4
alkyl, such as a C.sub.2-C.sub.4 alkyl, such as a C.sub.3-C.sub.4
alkyl, such as a C.sub.1-C.sub.3 alkyl. In this regard, the alkyl
may be heptyl, hexyl, pentyl (e.g., n-pentyl, sec-pentyl,
iso-pentyl, tert-pentyl, neo-pentyl), butyl (e.g., n-butyl,
sec-butyl, iso-butyl, tert-butyl), propyl (e.g., n-propyl,
iso-propyl), ethyl, methyl, etc. In one particular embodiment, the
alkyl may be butyl, such as tert-butyl.
[0048] In another embodiment, at least one of R.sub.1 and R.sub.2
may be a C.sub.2-C.sub.10 alkenyl. For instance, in one embodiment,
R.sub.1 may be a C.sub.2-C.sub.10 alkenyl. In another embodiment,
R.sub.2 may be a C.sub.2-C.sub.10 alkenyl. In a further embodiment,
R.sub.1 and R.sub.2 may be a C.sub.2-C.sub.10 alkenyl. In
particular, the alkenyl may be a C.sub.2-C.sub.7 alkenyl, such as a
C.sub.2-C.sub.6 alkenyl, such as a C.sub.2-C.sub.5 alkenyl, such as
a C.sub.2-C.sub.4 alkenyl.
[0049] In a further embodiment, at least one of R.sub.1 and R.sub.2
may be a C.sub.2-C.sub.10 alkynyl. For instance, in one embodiment,
R.sub.1 may be a C.sub.2-C.sub.10 alkynyl. In another embodiment,
R.sub.2 may be a C.sub.2-C.sub.10 alkynyl. In a further embodiment,
R.sub.1 and R.sub.2 may be a C.sub.2-C.sub.1 alkynyl. In
particular, the alkynyl may be a C.sub.2-C.sub.7 alkynyl, such as a
C.sub.2-C.sub.6 alkynyl, such as a C.sub.2-C.sub.5 alkynyl, such as
a C.sub.2-C.sub.4 alkynyl.
[0050] In another further embodiment, at least one of R.sub.1 and
R.sub.2 may be a C.sub.3-C.sub.12 aryl. For instance, in one
embodiment, R.sub.1 may be a C.sub.3-C.sub.12 aryl. In another
embodiment, R.sub.2 may be a C.sub.3-C.sub.12 aryl. In a further
embodiment, R.sub.1 and R.sub.2 may be a C.sub.3-C.sub.12 aryl. In
particular, the aryl may be a C.sub.3-C.sub.8 aryl, such as a
C.sub.3-C.sub.6 aryl, such as a C.sub.4-C.sub.6 aryl.
[0051] As indicated above, R.sub.3 includes a C.sub.1-C.sub.80
alkyl, a C.sub.2-C.sub.80 alkenyl, a C.sub.2-C.sub.40 alkynyl, or a
C.sub.3-C.sub.12 aryl. In one embodiment, R.sub.3 includes a
C.sub.1-C.sub.80 alkyl. In another embodiment, R.sub.3 includes a
C.sub.2-C.sub.80 alkenyl. In a further embodiment, R.sub.3 includes
a C.sub.2-C.sub.80 alkynyl. In an even further embodiment, R.sub.3
includes a C.sub.3-C.sub.12 aryl.
[0052] As indicated above, in one embodiment, R.sub.3 may include a
C.sub.1-C.sub.80 alkyl. In this regard, the R.sub.3 alkyl may be a
C.sub.1-C.sub.80 alkyl, such as a C.sub.3-C.sub.80 alkyl, such as a
C.sub.4-C.sub.70 alkyl, such as a C.sub.5-C.sub.60 alkyl, such as a
C.sub.6-C.sub.50 alkyl, such as a C.sub.8-C.sub.40 alkyl, such as a
C.sub.10-C.sub.30 alkyl, such as a C.sub.12-C.sub.26 alkyl, such as
a C.sub.12-C.sub.20 alkyl, such as a C.sub.13-C.sub.20 alkyl, such
as a C.sub.13-C.sub.15 alkyl. In addition, the R.sub.3 alkyl may be
a C.sub.1-C.sub.80 alkyl, such as a C.sub.10-C.sub.80 alkyl, such
as a C.sub.20-C.sub.80 alkyl, such as a C.sub.30-C.sub.80 alkyl.
For instance, the R.sub.3 alkyl may have 1 or more, such as 2 or
more, such as 3 or more, such as 4 or more, such as 5 or more, such
as 6 or more, such as 8 or more, such as 10 or more, such as 11 or
more, such as 12 or more, such as 13 or more, such as 14 or more,
such as 16 or more, such as 18 or more, such as 20 or more, such as
21 or more, such as 22 or more, such as 24 or more carbon atoms.
The R.sub.3 alkyl may have 80 or less, such as 70 or less, such as
60 or less, such as 50 or less, such as 40 or less, such as 30 or
less, such as 26 or less, such as 24 or less, such as 20 or less,
such as 18 or less, such as 16 or less, such as 15 or less carbon
atoms. In addition, the R.sub.3 alkyl may be a straight chain, a
branched chain, or cyclic. In one embodiment, the R.sub.3 alkyl is
a straight chain. In another embodiment, the R.sub.3 alkyl is a
branched chain. In a further embodiment, the R.sub.3 alkyl is
cyclic.
[0053] As indicated above, in one embodiment, R.sub.3 may be a
branched chain alkyl. In this regard, the R.sub.3 alkyl may be
provided by reacting a Guerbet alcohol with a monomer precursor
(i.e., a dialkylphenol or a deprotected dialkylphenol). As
generally known in the art, Guerbet alcohols are saturated primary
alcohols with branching of the carbon chain. In this regard, such
alcohols may be described as 2-alkyl-1-alkanols. Without being
limited, these alcohols may yield 2-butyl hexyl, 2-butyl octyl,
2-butyl decyl, 2-butyl dodecyl, 2-butyl tetradecyl, 2-butyl
hexadecyl, 2-butyl octadecyl, 2-hexyl octyl, 2-hexyl decyl, 2-hexyl
dodecyl, 2-hexyl tetradecyl, 2-hexyl hexadecyl, 2-hexyl octadecyl,
2-octyl hexyl, 2-octyl decyl, 2-octyl dodecyl, 2-octyl tetradecyl,
2-octyl hexadecyl, 2-octyl octadecyl, 2-decyl hexyl, 2-decyl octyl,
2-decyl dodecyl, 2-decyl tetradecyl, 2-decyl hexadecyl, 2-decyl
octadecyl, 2-dodecyl hexyl, 2-dodecyl octyl, 2-dodecyl decyl,
2-dodecyl tetradecyl, 2-dodecyl hexadecyl, 2-dodecyl octadecyl,
2-tetradecyl hexyl, 2-tetradecyl octyl, 2-tetradecyl decyl,
2-tetradecyl dodecyl, 2-tetradecyl hexadecyl, and 2-tetradecyl
octadecyl.
[0054] As indicated above, in one embodiment, R.sub.3 may include a
C.sub.2-C.sub.80 alkenyl. In this regard, the R.sub.3 alkenyl may
be a C.sub.2-C.sub.80 alkenyl, such as a C.sub.3-C.sub.80 alkenyl,
such as a C.sub.4-C.sub.70 alkenyl, such as a C.sub.5-C.sub.60
alkenyl, such as a C.sub.6-C.sub.50 alkenyl, such as a
C.sub.8-C.sub.40 alkenyl, such as a C.sub.10-C.sub.30 alkenyl, such
as a C.sub.12-C.sub.26 alkenyl, such as a C.sub.12-C.sub.20
alkenyl, such as a C.sub.13-C.sub.20 alkenyl, such as a
C.sub.13-C.sub.15 alkenyl. In addition, the R.sub.3 alkenyl may be
a C.sub.2-C.sub.80 alkenyl, such as a C.sub.10-C.sub.80 alkenyl,
such as a C.sub.2-C.sub.80 alkenyl, such as a C.sub.30-C.sub.80
alkenyl. For instance, the R.sub.3 alkenyl may have 2 or more, such
as 3 or more, such as 4 or more, such as 5 or more, such as 6 or
more, such as 8 or more, such as 10 or more, such as 11 or more,
such as 12 or more, such as 13 or more, such as 14 or more, such as
16 or more, such as 18 or more, such as 20 or more, such as 24 or
more carbon atoms. The R.sub.3 alkenyl may have 80 or less, such as
70 or less, such as 60 or less, such as 50 or less, such as 40 or
less, such as 30 or less, such as 26 or less, such as 24 or less,
such as 20 or less, such as 18 or less, such as 16 or less, such as
15 or less, such as 14 or less, such as 12 or less, such as 10 or
less, such as 8 or less, such as 6 or less carbon atoms. In
addition, the R.sub.3 alkenyl may be a straight chain or a branched
chain. In one embodiment, the R.sub.3 alkenyl is a straight chain.
In another embodiment, the R.sub.3 alkenyl is a branched chain.
[0055] As indicated above, in one embodiment, R.sub.3 may include a
C.sub.2-C.sub.80 alkynyl. In this regard, the R.sub.3 alkynyl may
be a C.sub.2-C.sub.80 alkynyl, such as a C.sub.3-C.sub.80 alkynyl,
such as a C.sub.4-C.sub.70 alkynyl, such as a C.sub.5-C.sub.60
alkynyl, such as a C.sub.6-C.sub.50 alkynyl, such as a
C.sub.8-C.sub.40 alkynyl, such as a C.sub.10-C.sub.30 alkynyl, such
as a C.sub.12-C.sub.26 alkynyl, such as a C.sub.12-C.sub.20
alkynyl, such as a C.sub.13-C.sub.20 alkynyl, such as a
C.sub.13-C.sub.15 alkynyl. In addition, the R.sub.3 alkynyl may be
a C.sub.2-C.sub.80 alkynyl, such as a C.sub.10-C.sub.80 alkynyl,
such as a C.sub.20-C.sub.80 alkynyl, such as a C.sub.30-C.sub.80
alkynyl. For instance, the R.sub.3 alkynyl may have 2 or more, such
as 3 or more, such as 4 or more, such as 5 or more, such as 6 or
more, such as 8 or more, such as 10 or more, such as 11 or more,
such as 12 or more, such as 13 or more, such as 14 or more, such as
16 or more, such as 18 or more, such as 20 or more, such as 24 or
more carbon atoms. The R.sub.3 alkynyl may have 80 or less, such as
70 or less, such as 60 or less, such as 50 or less, such as 40 or
less, such as 30 or less, such as 26 or less, such as 24 or less,
such as 20 or less, such as 18 or less, such as 16 or less, such as
15 or less, such as 14 or less, such as 12 or less, such as 10 or
less, such as 8 or less, such as 6 or less carbon atoms. In
addition, the R.sub.3 alkynyl may be a straight chain or a branched
chain. In one embodiment, the R.sub.3 alkynyl is a straight chain.
In another embodiment, the R.sub.3 alkynyl is a branched chain.
[0056] As indicated above, in one embodiment, R.sub.3 may include a
C.sub.3-C.sub.12 aryl. In this regard, the R.sub.3 aryl may be a
C.sub.3-C.sub.12 aryl, such as a C.sub.4-C.sub.12 aryl, such as a
C.sub.6-C.sub.12 aryl, such as a C.sub.6-C.sub.10 aryl, such as a
C.sub.6-C.sub.8 aryl. For instance, the R.sub.3 aryl may have 3 or
more, such as 4 or more, such as 5 or more, such as 6 or more
carbon atoms. The R.sub.3 aryl may have 12 or less, such as 10 or
less, such as 8 or less, such as 7 or less, such as 6 or less, such
as 5 or less carbon atoms. In addition, in one embodiment, the
R.sub.3 aryl may be polycyclic. The polycyclic aryl may include
fused, bridged, and spiro rings.
[0057] Regarding the R.sub.3 alkyl, R.sub.3 alkenyl, and R.sub.3
alkynyl, it should be understood that these may also include a
distribution. For instance, if R.sub.3 includes a distribution of
alkyls wherein the R.sub.3 alkyl is a C.sub.q-C.sub.r alkyl, the
R.sub.3 group of the copolymer may include other alkyls outside of
this range of q to r; however, the average chain length would be
from q to r. For example, if the R.sub.3 alkyl is a
C.sub.14-C.sub.24 alkyl, the R.sub.3 group of the copolymer may
include other alkyls outside of the range of 14 to 24 carbon atoms;
however, the average chain length would be between 14 and 24 carbon
atoms. Although the R.sub.3 alkyl is expressly mentioned in the
examples within this paragraph, it should be understood that such
also applies to the R.sub.3 alkenyl and the R.sub.3 alkynyl.
[0058] In one particular embodiment, R.sub.3 may be an alkyl, such
as a C.sub.12-C.sub.15 alkyl, such as a C.sub.13-C.sub.15 alkyl.
For instance, the phenolic antioxidant may be a mixture of phenolic
antioxidants wherein each R.sub.3 alkyl is a different
C.sub.12-C.sub.15 alkyl, such as a different C.sub.13-C.sub.15
alkyl. For instance, the mixture may include phenolic antioxidants
each including a linear C.sub.12 alkyl, a branched C.sub.12 alkyl,
a linear C.sub.13 alkyl, a branched C.sub.13 alkyl, a linear
C.sub.14 alkyl, a branched C.sub.14 alkyl, a linear C.sub.15 alkyl,
and/or a branched C.sub.15 alkyl. In one particular embodiment, the
mixture may include phenolic antioxidants each including a linear
C.sub.13 alkyl, a branched C.sub.13 alkyl, a linear C.sub.14 alkyl,
a branched C.sub.14 alkyl, a linear C.sub.15 alkyl, and/or a
branched C.sub.15 alkyl. Accordingly, one particular phenolic
antioxidant comprises C.sub.13-C.sub.15 linear and branched alkyl
esters of 3-(3'5'-di-t-butyl-4'-hydroxyphenyl) propionic acid.
[0059] Also, it should be understood that the antioxidant
composition may include a mixture of phenolic antioxidants. For
instance, the antioxidant composition may include at least one,
such as at least two, such as at least three phenolic antioxidants.
As an example, each of the phenolic antioxidants may have a
different R.sub.3 group as defined above. In combination, the
phenolic antioxidants may be present in the lubricant composition
in the percentages mentioned above. In addition or alternatively,
each individual phenolic antioxidant may be present in the
lubricant composition in the percentages mentioned above.
[0060] Furthermore, in one embodiment, the phenolic antioxidant may
be a liquid at ambient conditions (i.e., at atmospheric pressure
and a temperature of 25.degree. C.). By providing such phenolic
antioxidant as a liquid, it may be easily combined with the
phosphite antioxidant to form the antioxidant composition.
[0061] ii. Phosphite Antioxidant
[0062] As indicated herein, the antioxidant composition includes at
least one phosphite antioxidant. In this regard, the phosphite
antioxidant may have the following structure (II):
##STR00006##
wherein,
[0063] R.sub.4, R.sub.5, and R.sub.6 are each independently
hydrogen, alkyl, alkenyl, alkynyl, or aryl provided that at least
one of R.sub.4, R.sub.5, and R.sub.6 is not hydrogen; and
[0064] m, n, and o are each independently from 1 to 3.
[0065] As indicated above, R.sub.4, R.sub.5, and R.sub.6 are each
independently hydrogen, alkyl, alkenyl, alkynyl, or aryl provided
that at least one of R.sub.4, R.sub.5, and R.sub.6 is not hydrogen.
In this regard, at least one, such as at least two of R.sub.4,
R.sub.5, and R.sub.6 may be hydrogen provided that at least one of
R.sub.4, R.sub.5, and R.sub.6 is not hydrogen. Accordingly, in one
embodiment, at least one of R.sub.4, R.sub.5, and R.sub.6 may be an
alkyl. In another embodiment, at least one of R.sub.4, R.sub.5, and
R.sub.6 may be an alkenyl. In a further embodiment, at least one of
R.sub.4, R.sub.5, and R.sub.6 may be an alkynyl. In another further
embodiment, at least one of R.sub.4, R.sub.5, and R.sub.6 may be an
aryl.
[0066] In particular, R.sub.4, R.sub.5, and R.sub.6 may each
independently be a C.sub.1-C.sub.20 alkyl, a C.sub.2-C.sub.20
alkenyl, a C.sub.2-C.sub.20 alkynyl, or a C.sub.3-C.sub.12 aryl. In
this regard, in one embodiment, at least one of R.sub.4, R.sub.5,
and R.sub.6 may be a C.sub.1-C.sub.20 alkyl. In another embodiment,
at least one of R.sub.4, R.sub.5, and R.sub.6 may be a
C.sub.2-C.sub.20 alkenyl. In a further embodiment, at least one of
R.sub.4, R.sub.5, and R.sub.6 may be a C.sub.2-C.sub.20 alkynyl. In
another further embodiment, at least one of R.sub.4, R.sub.5, and
R.sub.6 may be a C.sub.3-C.sub.12 aryl.
[0067] As indicated above, in one embodiment, at least one of, such
as at least two of, such as all three of R.sub.4, R.sub.5, and
R.sub.6 may include an alkyl. In particular, it may include a
C.sub.1-C.sub.20 alkyl. In this regard, the alkyl may be a
C.sub.1-C.sub.20 alkyl, such as a C.sub.1-C.sub.16 alkyl, such as a
C.sub.1-C.sub.12 alkyl, such as a C.sub.1-C.sub.10 alkyl, such as a
C.sub.2-C.sub.8 alkyl, such as a C.sub.3-C.sub.6 alkyl, such as a
C.sub.4-C.sub.6 alkyl. For instance, the alkyl may have 1 or more,
such as 2 or more, such as 3 or more, such as 4 or more, such as 5
or more, such as 6 or more, such as 8 or more, such as 10 or more
carbon atoms. The alkyl may have 20 or less, such as 18 or less,
such as 16 or less carbon atoms, such as 14 or less, such as 12 or
less, such as 10 or less, such as 8 or less, such as 6 or less
carbon atoms. In addition, the alkyl may be a straight chain or a
branched chain. In one embodiment, the alkyl is a straight chain.
In another embodiment, the alkyl is a branched chain.
[0068] In one particular embodiment, at least one of R.sub.4,
R.sub.5, and R.sub.6 may be tert-butyl or tert-pentyl. For
instance, at least one of, such as at least two of, such as at
least three of R.sub.4, R.sub.5, and R.sub.6 may be tert-butyl. In
another embodiment, at least one of, such as at least two of, such
as at least three of R.sub.4, R.sub.5, and R.sub.6 may be
tert-pentyl.
[0069] In one particular embodiment, at least one of R.sub.4,
R.sub.5, and R.sub.6 may be nonyl. For instance, at least one of,
such as at least two of, such as at least three of R.sub.4,
R.sub.5, and R.sub.6 may be nonyl. In another embodiment, at least
one of, such as at least two of, such as at least three of R.sub.4,
R.sub.5, and R.sub.6 may be nonyl.
[0070] However, in one embodiment, the phosphite antioxidant may
include a very low amount of certain alkyls. For example, such
alkyls may be C.sub.8-C.sub.10, in particular C.sub.9 alkyls. In
this regard, in one embodiment, the alkyl may comprise less than
1,000 ppm, such as less than 500 ppm, such as less than 100 ppm,
such as less than 50 ppm, such as less than 25 ppm, such as less
than 10 ppm, such as less than 5 ppm, such as less than 1 ppm, such
as 0 ppm of such alkyl.
[0071] As indicated above, in one embodiment, at least one of, such
as at least two of, such as all three of R.sub.4, R.sub.5, and
R.sub.6 may include an alkenyl. In particular, it may include a
C.sub.2-C.sub.20 alkenyl. In this regard, the alkenyl may be a
C.sub.2-C.sub.20 alkenyl, such as a C.sub.2-C.sub.16 alkenyl, such
as a C.sub.2-C.sub.12 alkenyl, such as a C.sub.2-C.sub.10 alkenyl,
such as a C.sub.2-C.sub.8 alkenyl, such as a C.sub.3-C.sub.6
alkenyl, such as a C.sub.4-C.sub.6 alkenyl. For instance, the
alkenyl may have 2 or more, such as 3 or more, such as 4 or more,
such as 5 or more, such as 6 or more, such as 8 or more, such as 10
or more, such as 12 or more, such as 14 or more, such as 16 or more
carbon atoms. The alkenyl may have 20 or less, such as 18 or less,
such as 16 or less carbon atoms, such as 14 or less, such as 12 or
less, such as 10 or less, such as 8 or less, such as 6 or less
carbon atoms. In addition, the alkenyl may be a straight chain or a
branched chain. In one embodiment, the alkenyl is a straight chain.
In another embodiment, the alkenyl is a branched chain.
[0072] As indicated above, in one embodiment, at least one of, such
as at least two of, such as all three of R.sub.4, R.sub.5, and
R.sub.6 may include an alkynyl. In particular, it may include a
C.sub.2-C.sub.20 alkynyl. In this regard, the alkynyl may be a
C.sub.2-C.sub.20 alkynyl, such as a C.sub.2-C.sub.16 alkynyl, such
as a C.sub.2-C.sub.12 alkynyl, such as a C.sub.2-C.sub.10 alkynyl,
such as a C.sub.2-C.sub.8 alkynyl, such as a C.sub.3-C.sub.6
alkynyl, such as a C.sub.4-C.sub.6 alkynyl. For instance, the
alkynyl may have 2 or more, such as 3 or more, such as 4 or more,
such as 5 or more, such as 6 or more, such as 8 or more, such as 10
or more, such as 12 or more, such as 14 or more, such as 16 or more
carbon atoms. The alkynyl may have 20 or less, such as 18 or less,
such as 16 or less carbon atoms, such as 14 or less, such as 12 or
less, such as 10 or less, such as 8 or less, such as 6 or less
carbon atoms. In addition, the alkynyl may be a straight chain or a
branched chain. In one embodiment, the alkynyl is a straight chain.
In another embodiment, the alkynyl is a branched chain.
[0073] As indicated above, in one embodiment, at least one of, such
as at least two of, such as all three of R.sub.4, R.sub.5, and
R.sub.6 may include an aryl. In particular, it may include a
C.sub.3-C.sub.12 aryl. In this regard, the aryl may be a
C.sub.3-C.sub.12 aryl, such as a C.sub.4-C.sub.12 aryl, such as a
C.sub.6-C.sub.12 aryl, such as a C.sub.6-C.sub.10 aryl, such as a
C.sub.6-C.sub.8 aryl. For instance, the aryl may have 3 or more,
such as 4 or more, such as 5 or more, such as 6 or more carbon
atoms. The aryl may have 12 or less, such as 10 or less, such as 8
or less, such as 7 or less, such as 6 or less, such as 5 or less
carbon atoms. In addition, in one embodiment, the aryl may be
polycyclic. The polycyclic aryl may include fused, bridged, and
spiro ring systems.
[0074] In one embodiment, R.sub.4, R.sub.5, and R.sub.6 may all be
the same. By same, it should be understood that the substituent is
the same substituent group and having the same length. For example,
in one embodiment, R.sub.4, R.sub.5, and R.sub.6 may all be alkyl,
such as a C.sub.5 alkyl. In another embodiment, however, R.sub.4,
R.sub.5, and R.sub.6 may be different. For instance, in one
embodiment, all three R.sub.4, R.sub.5, and R.sub.6 may be
different. For instance, while they may have the same chemical
formula, they may be isomers having a different structure or
configuration. In another embodiment, at least two of R.sub.4,
R.sub.5, and R.sub.6 may be the same while the other is different.
By different, it should be understood that the substituent is a
different substituent group. For example, one of the groups may be
an alkyl while another may be an alkenyl. Alternatively, as another
example, at least two of the groups may be an alkyl wherein each
alkyl has a different chain length.
[0075] As indicated above, m, n, and o are each independently from
1 to 3. For instance, m may be from 1 to 3. In this regard, in one
embodiment, m may be 1. In another embodiment, m may be 2. In a
further embodiment, m may be 3. Similarly, n may be from 1 to 3. In
this regard, in one embodiment, n may be 1. In another embodiment,
n may be 2. In a further embodiment, n may be 3. Further, o may be
from 1 to 3. In this regard, in one embodiment, o may be 1. In
another embodiment, o may be 2. In a further embodiment, o may be
3.
[0076] Furthermore, in one embodiment, R.sub.4, R.sub.5, and
R.sub.6 may each independently be at the para position. For
instance, when m, n, and o are each independently 1, R.sub.4,
R.sub.5, and R.sub.6 may each independently be at the para
position. In another embodiment, R.sub.4, R.sub.5, and R.sub.6 may
each independently be at the ortho position. For instance, in one
embodiment, when m, n, and o are each independently 1, R.sub.4,
R.sub.5, and R.sub.6 may each independently be at the ortho
position. In another embodiment, when m, n, and o are each
independently 2, R.sub.4, R.sub.5, and R.sub.6 may each
independently be at the para position and the ortho position.
[0077] In this regard, in one embodiment, m, n, and o may each be
the same. For instance, in one embodiment, m, n, and o may be 1.
Accordingly, in one embodiment, the phosphite antioxidant may have
the following structure (III) wherein m, n, and o are each 1:
##STR00007##
In another embodiment, m, n, and o may be 2. In this regard, the
phosphite antioxidant may have the following structure (IV) wherein
m, n, and o are each 2:
##STR00008##
In a further embodiment, m, n, and o may be 3.
[0078] In addition, it should be understood that in one embodiment,
all three of m, n, and o may be different. For instance, at least
one of m, n, and o may be 1, while another of m, n, and o may be 2,
while another of m, n, and o may be 3.
[0079] In a further embodiment, at least two of m, n, and o may be
the same while the other is different. For instance, at least two
of m, n, and o may be 1 while the third may be 2 or 3, such as 2 in
one embodiment or 3 in another embodiment. In this regard, the
phosphite antioxidant may have the following structure (V) wherein
n and o are 1 and m is 2:
##STR00009##
Alternatively, at least two of m, n, and o may be 2 while the third
may be 1 or 3, such as 1 in one embodiment or 3 in another
embodiment. In this regard, the phosphite antioxidant may have the
following structure (VI) wherein m and n are 2 and o is 1:
##STR00010##
In a further embodiment, at least two of m, n, and o may be 3 while
the third may be 1 or 2, such as 1 in one embodiment or 2 in
another embodiment.
[0080] In addition, it should be understood that any of the
aforementioned phosphite antioxidants of structures (III), (IV),
(V), or (VI) may be utilized individually or in combination. For
instance, at least one, such as at least two, such as at least
three, such as at least all four of the aforementioned phosphite
antioxidants of structures (III), (IV), (V), or (VI) may be
utilized in the antioxidant composition.
[0081] Also, it should be understood that the antioxidant
composition may include a mixture of phosphite antioxidants. For
instance, the antioxidant composition may include at least one,
such as at least two, such as at least three, such as at least four
phosphite antioxidants. As an example, each of the phosphite
antioxidants may have a different number of substituent groups
and/or different substituent groups as defined above. In
combination, the phosphite antioxidants may be present in the
lubricant composition in the percentages mentioned above. In
addition or alternatively, each individual phosphite antioxidant
may be present in the lubricant composition in the percentages
mentioned above.
[0082] Furthermore, when a mixture of phosphite antioxidants are
utilized, they may be utilized within certain amounts. For
instance, the weight ratio of the tris(monoalkylaryl)phosphites to
the combination of bis(monoalkylaryl)dialkylaryl phosphites,
bis(dialkylaryl)monoalkylaryl phosphites, and
tris(dialkylaryl)phosphites may be within a certain range.
Furthermore, the weight ratio of bis(monoalkylaryl)dialkylaryl
phosphites to the combination of tris(monoalkylaryl)phosphites,
bis(dialkylaryl)monoalkylaryl phosphites, and
tris(dialkylaryl)phosphites may be within a certain range. In
addition, the weight ratio of bis(dialkylaryl)monoalkylaryl
phosphites to the combination of tris(monoalkylaryl)phosphites,
bis(monoalkylaryl)dialkylaryl phosphites, and
tris(dialkylaryl)phosphites may be within a certain range. Such
weight ratios may be about 0.01 or more, such as about 0.033 or
more, such as about 0.05 or more, such as about 0.1 or more, such
as about 0.15 or more, such as about 0.2 or more, such as about 0.3
or more, such as about 0.33 or more, such as about 0.4 or more,
such as about 0.5 or more, such as about 0.6 or more, such as about
0.66 or more. The weight ratios may be about 10 or less, such as
about 8 or less, such as about 6 or less, such as about 4 or less,
such as about 3 or less, such as about 2 or less, such as about 1.7
or less, such as about 1.5 or less, such as about 1.2 or less, such
as about 1.1 or less, such as about 1 or less, such as about 0.9 or
less, such as about 0.75 or less, such as about 0.66 or less, such
as about 0.6 or less, such as about 0.55 or less, such as about 0.4
or less, such as about 0.2 or less, such as about 0.15 or less,
such as about 0.11 or less, such as about 0.1 or less, such as
about 0.05 or less, such as about 0.02 or less. In one embodiment,
the molar ratio of the phenolic antioxidant to the phosphite
antioxidant may also be within the aforementioned ranges.
[0083] Also, the weight ratio of the tris(dialkylaryl)phosphites to
the combination of bis(monoalkylaryl)dialkylaryl phosphites,
bis(dialkylaryl)monoalkylaryl phosphites and
tris(monoalkylaryl)phosphites may also be within a certain range.
For instance, the weight ratio may be about 0.0001 or more, such as
about 0.0002 or more, such as about 0.001 or more, such as about
0.01 or more, such as about 0.1 or more, such as about 0.2 or more,
such as about 0.5 or more. The weight ratio may be about 5 or less,
such as about 3 or less, such as about 2.5 or less, such as about
1.5 or less, such as about 1 or less, such as about 0.5 or less,
such as about 0.1 or less, such as about 0.05 or less, such as
about 0.02 or less, such as about 0.01 or less, such as about 0.005
or less.
[0084] For instance, the weight ratio of the phenolic antioxidant
to the phosphite antioxidant may be within a certain range. For
instance, the weight ratio may about 0.1 or more, such as about 0.2
or more, such as about 0.3 or more, such as about 0.33 or more,
such as about 0.4 or more, such as about 0.5 or more, such as about
0.6 or more, such as about 0.66 or more. The weight ratio may be
about 10 or less, such as about 8 or less, such as about 6 or less,
such as about 4 or less, such as about 3 or less, such as about 2
or less, such as about 1.7 or less, such as about 1.5 or less, such
as about 1.2 or less, such as about 1 or less, such as about 0.9 or
less, such as about 0.75 or less, such as about 0.66 or less, such
as about 0.6 or less, such as about 0.55 or less. In one
embodiment, the molar ratio of the phenolic antioxidant to the
phosphite antioxidant may also be within the aforementioned
ranges.
[0085] As examples, the phosphite antioxidant may include, but is
not limited to, tris-4-tert-butyl phenyl phosphite, tris
2,4-di-tert-butyl phenyl phosphite,
bis(4-tert-butylphenyl)-2,4-di-tert-butylphenyl phosphite,
bis(2,4-di-tert-butylphenyl)-4-tert-butylphenyl phosphite, tris
4-tert-pentyl phenyl phosphite, tris 2,4-di-tert-pentyl phenyl
phosphite, bis(4-tert-pentylphenyl)-2,4-di-tert-pentylphenyl
phosphite, bis(2,4-di-tert-pentylphenyl)-4-tert-pentylphenyl
phosphite, the like, as well as mixtures thereof.
[0086] The phosphite antioxidant may have a certain molecular
weight. For instance, the molecular weight may be 400 g/mol or
more, such as 450 g/mol or more, such as 500 g/mol or more, such as
550 g/mol or more, such as 600 g/mol or more, such as 650 g/mol or
more. The molecular weight may be 1,000 g/mol or less, such as 900
g/mol or less, such as 800 g/mol or less, such as 750 g/mol or
less, such as 700 g/mol or less, such as 650 g/mol or less, such as
600 g/mol or less.
[0087] The phosphite antioxidant may also have a certain phosphorus
content. For instance, the phosphorus content may be 0.5 wt. % or
more, such as 1 wt. % or more, such as 2 wt. % or more, such as 3
wt. % or more, such as 4 wt. % or more, such as 4.5 wt. % or more,
such as 4.8 wt. % or more, such as 5 wt. % or more. The phosphorus
content may be 10 wt. % or less, such as 8 wt. % or less, such as 6
wt. % or less, such as 5.5 wt. % or less, such as 5.3 wt. % or
less.
[0088] The phosphite antioxidant may also have a certain kinematic
viscosity. For instance, the kinematic viscosity may be 11,000
mm.sup.2/s or less, such as 8,000 mm.sup.2/s or less, such as 7,500
mm.sup.2/s or less, such as 6,500 mm.sup.2/s or less, such as 5,500
mm.sup.2/s or less, such as 5,000 mm.sup.2/s or less, such as 3,000
mm.sup.2/s or less when measured at 30.degree. C. The kinematic
viscosity may be 1 mm.sup.2/s or more, such as 50 mm.sup.2/s or
more, such as 100 mm.sup.2/s or more, such as 500 mm.sup.2/s or
more, such as 1,000 mm.sup.2/s or more, such as 2,000 mm.sup.2/s or
more, such as 3,000 mm.sup.2/s or more, such as 4,000 mm.sup.2/s or
more when measured at 30.degree. C. The viscosity may be determined
using a glass capillary viscometer according to ASTM D445-19.
[0089] Furthermore, in one embodiment, the phosphite antioxidant
may be a liquid at ambient conditions (i.e., at atmospheric
pressure and a temperature of 25.degree. C.). By providing such
phosphite antioxidant as a liquid, it may be easily combined with
the phenolic antioxidant to form the antioxidant composition.
B. Lubricating Oil
[0090] In addition to the antioxidant composition, the lubricant
composition also comprises a lubricating oil. The lubricating oil
is not necessarily limited by the present invention. Regardless,
the lubricating oil may be present in the composition in an amount
of about 70 wt. % or more, such as 75 wt. % or more, such as 80 wt.
% or more, such as 85 wt. % or more, such as 90 wt. % or more. The
lubricating oil may be present in the lubricant composition in an
amount of less than 100 wt. %, such as 99 wt. % or less, such as 97
wt. % or less, such as 95 wt. % or less, such as 93 wt. % or less,
such as 90 wt. % or less.
[0091] The lubricating oil may include a natural lubricating oil, a
synthetic lubricating oil, or a mixture thereof. In one embodiment,
the oil may be a natural lubricating oil. In another embodiment,
the oil may be a synthetic lubricating oil. In a further
embodiment, the oil may be a mixture of a natural lubricating oil
and a synthetic lubricating oil.
[0092] Furthermore, the lubricating oil may have a certain
kinematic viscosity. For example, the kinematic viscosity may be 3
mm.sup.2/s or more, such as 3.5 mm.sup.2/s or more, such as 4
mm.sup.2/s or more, such as 4.5 mm.sup.2/s or more, such as 5
mm.sup.2/s or more at 100.degree. C. The kinematic viscosity may be
200 mm.sup.2/s or less, such as 150 mm.sup.2/s or less, such as 125
mm.sup.2/s or less, such as 100 mm.sup.2/s or less, such as 80
mm.sup.2/s or less, such as 60 mm.sup.2/s or less, such as 50
mm.sup.2/s or less, such as 30 mm.sup.2/s or less, such as 20
mm.sup.2/s or less, such as 15 mm.sup.2/s or less, such as 12
mm.sup.2/s or less, such as 10 mm.sup.2/s or less, such as 9
mm.sup.2/s or less, such as 8 mm.sup.2/s or less at 100.degree. C.
The kinematic viscosity can be determined in accordance with ASTM
D445-19.
[0093] The lubricating oil may be one of lubricating viscosity
comprising a Group I, Group II, Group III, Group IV, or synthetic
ester base stock. In general, the various base stock groups are
identified chemically and physically in the American Petroleum
Institute (API) publication Engine Oil Licensing and Certification
System, Industry Services Department, 14th Ed. (December 1996)
Addendum 1 (December 1998), which is hereby incorporated by
reference in its entirety for any purpose.
[0094] In general, the Group I mineral oil base stocks may contain
less than 90 wt. % of saturates. Also, the Group I mineral base
stocks may contain greater than 0.3 wt. % of sulfur. Furthermore,
the Group I mineral base stocks may have a viscosity index of 80 or
more, such as 85 or more, such as 90 or more, such as 100 or more
to 120 or less, such as 115 or less, such as 110 or less. The
viscosity index may be determined in accordance to ASTM
D2270-10.
[0095] In general, the Group II mineral oil base stocks may contain
80 wt. % or more, such as 85 wt. % or more, such as 90 wt. % or
more, such as 93 wt. % or more, such as 95 wt. % or more saturates.
The Group II mineral base stocks may contain 0.1 wt. % or less,
such as 0.05 wt. % or less, such as 0.03 wt. % or less, such as
0.01 wt. % or less of sulfur. Furthermore, the Group II mineral
base stocks may have a viscosity index of 70 or more, such as 75 or
more, such as 80 or more, such as 85 or more, such as 90 or more,
such as 100 or more to 120 or less, such as 115 or less, such as
110 or less. The viscosity index may be determined in accordance to
ASTM D2270-10.
[0096] In general, Group III mineral oil base stocks may contain 80
wt. % or more, such as 85 wt. % or more, such as 90 wt. % or more,
such as 93 wt. % or more, such as 95 wt. % or more saturates. The
Group III mineral base stocks may contain 0.1 wt. % or less, such
as 0.05 wt. % or less, such as 0.03 wt. % or less, such as 0.01 wt.
% or less of sulfur. Furthermore, the Group III mineral base stocks
may have a viscosity index of 120 or more, such as 125 or more,
such as 130 or more. The viscosity index may be determined in
accordance to ASTM D2270-10.
[0097] In general, the Group IV base stocks may include
poly-.alpha.-olefins. In addition to the poly-.alpha.-olefins, the
lubricating oil may include silicon-based oils, such as polyalkyl-,
polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate
oils, comprise another useful class of synthetic lubricating
oils.
[0098] In general, the ester base stocks may include esters of
dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl
succinic acids, alkenyl succinic acids, maleic acid, azelaic acid,
suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic
acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic
acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl
alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol,
diethylene glycol monoether, propylene glycol, etc.). In this
regard, specific examples of these esters may include, but are not
limited to, dibutyl adipate, bis(2-ethylhexyl) sebacate, di-n-hexyl
fumarate, dioctyl sebacate, di-isooctyl azelate, di-isodecyl
azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate,
2-ethylhexyl diester of linoleic acid dimer, complex ester formed
by reacting one mole of sebacic acid with two moles of
tetraethylene glycol and two moles of 2-ethylhexanoic acid, and the
like. The esters useful as base stocks may also include those made
from C.sub.5-C.sub.12 monocarboxylic acids and polyols and polyol
ethers, such as neopentyl glycol, trimethylol propane,
pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
[0099] In one embodiment, natural lubricating oils may include, but
are not limited to, animal oils, such as lard oil, tallow oil,
vegetable oils including canola oils, castor oils, and sunflower
oils, for example, petroleum oils, mineral oils, and oils derived
from coal or shale.
[0100] In one embodiment, synthetic lubricating oils may include
hydrocarbon oils and halo-substituted hydrocarbon oils, such as
polymerized and interpolymerized olefins, gas-to-liquids prepared
by Fischer-Tropsch technology, alkylbenzenes, polyphenyls,
alkylated diphenyl ethers, alkylated diphenyl sulfides, as well as
their derivatives, analogs, homologs, and the like. Synthetic
lubricating oils may also include alkylene oxide polymers,
interpolymers, copolymers, and derivatives thereof, wherein the
terminal hydroxyl groups have been modified by esterification, and
etherification, for example.
[0101] In general, the lubricating oil may be derived from
unrefined, refined, re-refined oils, or mixtures thereof. For
instance, unrefined oils may be obtained directly from a natural
source or synthetic source (e.g., coal, shale, or tar and bitumen)
without further purification or treatment. Examples of unrefined
oils may include, but are not limited to, a shale oil obtained
directly from a retorting operation, a petroleum oil obtained
directly from distillation, or an ester oil obtained directly from
an esterification process, each of which is then used without
further treatment. Furthermore, refined oils are similar to
unrefined oils, except that refined oils have been treated in one
or more purification steps to improve one or more properties.
Suitable purification techniques can include, but are not limited
to, distillation, hydrotreating, dewaxing, solvent extraction, acid
or base extraction, filtration, percolation, and the like, all of
which are well-known to those skilled in the art. In addition,
re-refined oils are obtained by treating refined oils in processes
similar to those used to obtain the refined oils. These re-refined
oils are also known as reclaimed or reprocessed oils and often are
additionally processed by techniques for removal of spent additives
and oil breakdown products.
[0102] Also, it should be understood that the lubricating oil may
include a mixture of lubricating oils. For instance, the
lubricating oil may include at least one, such as at least two,
such as at least three, such as at least four lubricating oils.
C. Lubricant Composition
[0103] In addition to the antioxidant composition and lubricating
oil as mentioned above, the lubricant composition may also include
other additives. For instance, in one embodiment, the lubricant
composition may further comprise an alkanolamine. As generally
understood in the art, alkanolamines contain both a hydroxyl group
and an amino group on an alkane backbone. The alkanolamine may
include, but is not limited to, a methanolamine, an ethanolamine, a
propanolamine, or a mixture thereof. In one embodiment, the
alkanolamine may be an ethanolamine, a propanolamine, or a mixture
thereof. In a further embodiment, the alkanolamine may include a
propanolamine.
[0104] Furthermore, the alkanolamine may be a monoalkanolamine, a
dialkanolamine, a trialkanolamine, or a mixture thereof. In one
embodiment, the alkanolamine may be a dialkanolamine, a
trialkanolamine, or a mixture thereof. In a further embodiment, the
alkanolamine may be a trialkanolamine. Examples of these
alkanolamines may specifically include monoethanolamine,
diethanolamine, triethanolamine, monoisopropanolamine,
diisopropanolamine, triisopropanolamine, or a mixture thereof. In
one particular embodiment, the alkanolamine may include
triisopropanolamine. Other alkanolamines may include, but are not
limited to, octyl-bis(2-ethanol)amine, nonyl-bis(2-ethanol)amine,
decyl-bis(2-ethanolamine, undecyl-bis(2-ethanol)amine,
dodecyl-bis(2-ethanol)amine, tridecyl-bis(2-ethanol)amine,
tetradecyl-bis(2-ethanol)amine, pentadecyl-bis(2-ethanol)amine,
hexadecyl-bis(2-ethanol)amine, heptadecyl-bis(2-ethanol)amine,
octadecyl-bis(2-ethanol)amine, octyl-bis(2-propanol)amine,
nonyl-bis(2-propanol)amine, decyl-bis(2-propanol)amine,
undecyl-bis(2-propanol)amine, dodecyl-bis(2-propanol)amine,
tridecyl-bis(2-propanol)amine, tetradecyl-bis(2-propanol)amine,
pentadecyl-bis(2-propanol)amine, hexadecyl-bis(2-propanol)amine,
heptadecyl-bis(2-propanol)amine, octadecyl-bis(2-propanol)amine,
and mixtures thereof.
[0105] When present, the alkanolamine may be in the lubricant
composition in an amount of 5 wt. % or less, such as 4 wt. % or
less, such as 3 wt. % or less, such as 2 wt. % or less, such as 1.5
wt. % or less, such as 1 wt. % or less, such as 0.5 wt. % or less,
such as 0.4 wt. % or less, such as 0.3 wt. % or less, such as 0.2
wt. % or less, such as 0.1 wt. % or less, such as 0.05 wt. % or
less, such as 0.01 wt. % or less based on the combined weight of
the phosphite antioxidants and the alkanolamine. The alkanolamine
may be present in the lubricant composition in an amount of 0.001
wt. % or more, such as 0.01 wt. % or more, such as 0.1 wt. % or
more, such as 0.2 wt. % or more based on the combined weight of the
phosphite antioxidants and the alkanolamine. In one embodiment, the
alkanolamine may be in the lubricant composition in an amount of
about 0 wt. %. In another embodiment, the aforementioned weight
percentages may apply to the alkanolamine based on the total weight
of the lubricant composition.
[0106] The lubricant composition may also include other additives
as generally known in the art. For instance, these may include, but
are not limited to, dispersants, detergents, antiwear agents,
antioxidants, friction modifiers, seal swell agents, demulsifiers,
VI (viscosity index) improvers, pour point depressants,
antifoamants, corrosion inhibitors, metal deactivators, etc. Such
additives are well known to those skilled in the art and thus are
not limited by the present invention. When utilized, they may be
present in the lubricant composition in an amount of 10 wt. % or
less, such as 7 wt. % or less, such as 5 wt. % or less, such as 4
wt. % or less, such as 3 wt. % or less, such as 2 wt. % or less,
such as 1.5 wt. % or less, such as 1 wt. % or less, such as 0.5 wt.
% or less, such as 0.3 wt. % or less, such as 0.1 wt. % or less. In
one particular embodiment, a respective additive may be present in
the lubricant composition in an amount of 0 wt. %.
[0107] In addition, the present invention is also directed to a
method of forming the lubricant composition. The method is not
necessarily limited by the present invention. In this regard, the
method may comprise a step of combining a lubricating oil with the
antioxidant composition as defined herein. For instance, prior to
the combining step, the antioxidant composition including the
phenolic antioxidant and phosphite antioxidant as disclosed herein
may be prepared. Then, the lubricating oil may be combined with the
antioxidant composition. Alternatively, the lubricating oil may
first be combined with at least one of the phenolic antioxidant and
the phosphite antioxidant and then combined with the other of the
phenolic antioxidant and the phosphite antioxidant. In this regard,
although not directly combined with the antioxidant composition
initially, the lubricant composition in the end may contain such
antioxidant composition.
[0108] Regardless of the method in which it is manufactured, the
lubricant composition as disclosed herein may be utilized in a
variety of applications and thus is not limited by the present
invention. For instance, the lubricant composition can be used as
an automatic crank case lubricant, an automatic gear lubricant, an
industrial gear lubricant, a gas engine lubricant, a steam and gas
turbine lubricant, an automatic transmission fluid, a compressor
lubricant, a metal-working lubricant, a transmission fluid, a
hydraulic fluid, etc. The lubricant composition of the present
invention, in one embodiment, may be particularly useful as a
passenger vehicle engine oil product.
EXAMPLES
Test Methods
[0109] Standard RPVOT Oxidation Induction Time:
[0110] The standard rotating pressure vessel oxidation test (RPVOT)
was conducted according to ASTM D2272-14a. The standard RPVOT test
conditions were as follows: copper catalyst coil weight (55.6+/-0.3
g), sample size weight (50+/-0.5 g), distilled water volume (5 mL),
temperature (150.degree. C.), oxygen initial pressure at room
temperature (90 psi), and pressure drop to end test (25.4 psi). The
RPVOT utilized an oxygen-pressured vessel to evaluate the oxidation
stability, in the presence of water and a copper catalyst coil at
150.degree. C. The test lubricant composition, water, and a copper
catalyst coil, which were separately contained in a covered glass
container, were placed in a vessel equipped with a pressure gauge.
The vessel was charged with oxygen to a pressure of 90 psi at room
temperature. The vessel was rotated axially at 100 rpm at an angle
of 30 degrees from the horizontal. The number of minutes required
to reach a specific drop of 25.4 psi in gauge pressure indicated
the oxidation stability of the test sample. For this test, an
average value of two or more samples was obtained.
[0111] Dry RPVOT Oxidation Induction Time:
[0112] The dry rotating pressure vessel oxidation test (RPVOT) was
conducted according to a modified ASTM D2272-14a by using a TANNAS
Quantum.TM. oxidation tester and the method mentioned above except
that water was not charged into the test beaker. For this test, an
average value of two or more samples was obtained.
[0113] PDSC Oxidation Induction Time:
[0114] The pressurized differential scanning calorimetry (PDSC)
measured the oxidation induction time of the lubricant composition.
The instrument used was a TA Instruments.TM. Q20P, Pressure DSC.
The PDSC test conditions were as follows: isothermal temperature
(160.degree. C.), cell pressure (500+/-25 psi of O.sub.2), O.sub.2
gas flow rate through the cell (100 mL/min), sample holder (open
aluminum pan), lubricant composition sample size (2.9-3.1 mg, and
induction time based on the onset temperature of the exothermic
oxidation peak (enthalpy change)). At the beginning of a PDSC run,
the DSC cell was heated at a rate of 100.degree. C./minute to the
isothermal temperature (160.degree. C.), then held isothermally for
2 minutes. The cell was then pressurized to 500 psi and held
isothermally at 160.degree. C. The induction time was measured from
the start time of the cell pressurization until the enthalpy change
was observed.
[0115] Expected Standard RPVOT, Dry RPVOT, and PDSC Oxidation
Induction Times:
[0116] Using the aforementioned methods, the oxidation induction
times were determined for each antioxidant individually, rather
than using both in combination. Then, using a linear extrapolation,
the expected value was determined as a function of the weight
percentage of each antioxidant in the composition. As an example,
if antioxidant A had an actual oxidation induction time of 100
minutes and antioxidant B had an actual oxidation induction time of
200 minutes, an antioxidant composition having antioxidant A in an
amount of 25 wt. % and antioxidant B in an amount of 75 wt. % would
have an expected oxidation induction time of 175 minutes (e.g.,
0.25*100 minutes+0.75*200 minutes). Similarly, an antioxidant
composition having antioxidant A in an amount of 40 wt. % and
antioxidant B in an amount of 60 wt. % would have an expected
oxidation induction time of 160 minutes (e.g., 0.40*100
minutes+0.60*200 minutes). As another example, an antioxidant
composition having antioxidant A in an amount of 66.6 wt. % and
antioxidant B in an amount of 33.3 wt. % would have an expected
oxidation induction time of 133.33 minutes (e.g., 0.66*100
minutes+0.33*200 minutes).
[0117] TEOST 33C Deposit:
[0118] The thermo-oxidative engine oil simulation test (TEOST 33C)
was performed according to ASTM D6335-16. The TEOST 33C test
conditions were as follows. A 116 mL sample of the lubricant
composition containing 100 mg/kg of ferric naphthenate was placed
into the reaction chamber and heated and stirred at a temperature
of 100.degree. C. Nitrous oxide and moist air were injected from a
bottom channel opening, each at a flow rate of 3.5 mL/min. The
catalyzed oil was pumped past a tared depositor rod that was
resistively heated through twelve, 9.5 min temperature cycles that
went from 200.degree. C. to 480.degree. C. When the twelve-cycle
program was complete, the depositor rod was rinsed of oil residue
and dried and the gross rod mass was determined. The remaining test
oil sample, including washing from the deposit rod, was flushed
from the system and filtered through a tared filter. The mass of
deposits on the rod plus the mass of deposits on the filter was
determined to be the total deposit. For this test, an average value
of two or more samples was obtained.
[0119] Antiwear:
[0120] The antiwear performance was determined according to ASTM
D4172-18. In particular, a 4-ball wear test was conducted wherein
three steel balls are clamped together and covered with the
lubricant. A fourth steel ball, referred to as the top ball, is
pressed with a normal force of 40 kgf onto three clamped balls for
three-point contact. The temperature of the lubricant composition
is regulated at 75.degree. C. and then the top ball is rotated at
1200 rpm for 60 min. Lubricants are compared by measuring the
average size of the wear scar diameters worn on the three lower
clamped balls. In general, higher antiwear values correspond to a
greater wear and poorer antiwear performance while lower antiwear
values corresponding to better antiwear performance.
[0121] Expected Antiwear:
[0122] Using the aforementioned method, the antiwear performance
was determined for each antioxidant individually, rather than using
both in combination. Then, using a linear extrapolation, the
expected value was determined as a function of the weight
percentage of each antioxidant in the composition. As an example,
if antioxidant A had an actual wear scar of 0.8 mm and antioxidant
B had an actual wear scar of 0.4 mm, an antioxidant composition
having antioxidant A in an amount of 25 wt. % and antioxidant B in
an amount of 75 wt. % would have an expected wear scar of 0.5 mm
(e.g., 0.25*0.8 mm+0.75*0.4 mm). Similarly, an antioxidant
composition having antioxidant A in an amount of 40 wt. % and
antioxidant B in an amount of 60 wt. % would have an expected wear
scar of 0.56 mm (e.g., 0.40*0.8 mm+0.60*0.4 mm). As another
example, an antioxidant composition having antioxidant A in an
amount of 66.6 wt. % and antioxidant B in an amount of 33.3 wt. %
would have an expected wear scar of 0.66 mm (e.g., 0.66*0.8
mm+0.33*0.4 mm).
Example 1
[0123] This example demonstrated the efficacy of the antioxidant
composition in a particular lubricating oil. In particular, the
standard RPVOT oxidation induction time, dry RPVOT oxidation
induction time, PDSC oxidation induction time, TEOST 33C deposit,
and antiwear performance were determined.
[0124] The lubricating oil was EHC.TM. 65 from ExxonMobil. EHC.TM.
65, which includes severely treated based oils, is a Group 2 base
oil. For each sample, the total amount of the antioxidant(s) in
each sample was 1 wt. % in the EHC.TM. 65.
[0125] The phosphite antioxidant included one or more phosphite
antioxidants having the structure as defined herein wherein m, n,
and o are each independently 1 or 2 and wherein R.sub.4, R.sub.5,
and R.sub.6 are each a C.sub.5 alkyl (i.e., tert-pentyl).
[0126] The phenolic antioxidant included one or more phenolic
antioxidants having the structure as defined herein wherein A is a
C.sub.2 alkylene, X is --C(O)O--, R.sub.1 and R.sub.2 are a C.sub.4
alkyl (i.e., tert-butyl), and R.sub.3 is a C--C alkyl.
[0127] The lubricant composition was prepared by mixing the
antioxidants with the lubricating oil at 50.degree. C. for 30
minutes.
TABLE-US-00001 TABLE 1 Effect of Antioxidant Composition on RPVOT,
PDSC, TEOST 33C, and Antiwear Performance Compar- Sample Sample
Sample Compar- ative 1 1 2 3 ative 2 Phosphite 1 0.75 0.5 0.25 0
Antioxidant (wt. %) Phenolic 0 0.25 0.5 0.75 1 Antioxidant (wt. %)
Dry RPVOT 529 572 554 476 188 (min) Expected Dry -- 443 358 273 --
RPVOT (min) % Increase -- 29.1 54.7 74.4 -- Dry RPVOT Standard 272
310 364 324 184 RPVOT (min) Expected -- 250 228 206 -- Standard
RPVOT (min) % Increase -- 24.0 59.6 57.3 -- Standard RPVOT PDSC 43
168 122 96 81 (min) Expected -- 52 62 72 -- PDSC (min) % Increase
-- 223.1 96.8 33.3 -- Dry PDSC TEOST 33C 11.4 10.8 11.3 12.1 9.7
(mg) Wear Scar 0.86 0.48 0.90 0.77 0.73 (mm) Expected -- 0.83 0.80
0.76 -- Wear Scar (mm) % Change -- -42.2 12.5 -6.6 -- Wear Scar
[0128] As indicated in the table above, compared to an expected
oxidation induction time, the inventive samples containing both the
phenolic antioxidant and the phosphite antioxidant demonstrate
improved antioxidation performance. In particular, compared to the
expected oxidation induction time, the actual oxidation induction
times were greater thereby demonstrating a synergistic effect when
utilizing both antioxidants in combination. Furthermore, the actual
oxidation induction time when utilizing the antioxidant composition
containing both antioxidants was greater than the oxidation
induction time when utilizing each antioxidant individually in
certain instances. Also, the amount of deposits when utilizing the
antioxidant composition also appeared to be unaffected. For
example, the amount of deposits appeared to be substantially
similar to the amount of deposits exhibited when utilizing each
antioxidant individually. In addition, in certain examples, the
antioxidant composition resulted in a lubricant composition that
appeared to demonstrate improved antiwear performance.
Example 2
[0129] This example demonstrated the oxidation performance of the
phosphite antioxidant and the phenolic antioxidant individually. In
addition, in one example, the phosphite antioxidant was combined
with triisopropanolamine. In particular, the standard RPVOT
oxidation induction time, dry RPVOT oxidation induction time, PDSC
oxidation induction time and TEOST 33C deposit were determined.
[0130] The lubricating oil was EHC.TM. 65 from ExxonMobil. EHC.TM.
65, which includes severely treated based oils, is a Group 2 base
oil. For each sample, the total amount of the antioxidant in each
sample was 0.5 wt. % in the EHC.TM. 65.
[0131] The phosphite antioxidant included one or more phosphite
antioxidants having the structure as defined herein wherein m, n,
and o are each independently 1 or 2 and wherein R.sub.4, R.sub.5,
and R.sub.6 are each a C.sub.5 alkyl (i.e., tert-pentyl). When
present, the amount of triisopropanolamine was from 0.10 wt. % to
0.30 wt. % based on the combined weight of the phosphite
antioxidants and the triisopropanolamine.
[0132] The phenolic antioxidant included one or more phenolic
antioxidants having the structure as defined herein wherein A is a
C.sub.2 alkylene, X is --C(O)O--, R.sub.1 and R.sub.2 are a C.sub.4
alkyl (i.e., tert-butyl), and R.sub.3 is a C--C alkyl.
[0133] The lubricant composition was prepared by mixing the
antioxidants with the lubricating oil at 50.degree. C. for 30
minutes.
TABLE-US-00002 TABLE 2 Effect of Triisopropanolamine on RPVOT and
PDSC Phosphite Phenolic Phosphite Antioxidant at Antioxidant at
Antioxidant at 0.5 wt. % (with 0.5 wt. % 0.5 wt. %
Triisopropanolamine) Dry 144 516 513 RPVOT (min) Standard 369 976
937 RPVOT* (min) PDSC (min) 76.2 42.2 42.2 *EHC .TM. 65 was
combined with a rust inhibitor and an anti-corrosion agent.
Example 3
[0134] This example demonstrated the efficacy of the antioxidant
composition in a particular lubricating oil. In particular, the
standard RPVOT oxidation induction time, dry RPVOT oxidation
induction time, TEOST 33C deposit, and antiwear performance were
determined.
[0135] The lubricating oil was EHC.TM. 65 from ExxonMobil. EHC.TM.
65, which includes severely treated based oils, is a Group 2 base
oil. For each sample, the total amount of the antioxidant(s) in
each sample was 1 wt. % in the EHC.TM. 65.
[0136] The phosphite antioxidant included one or more phosphite
antioxidants having the structure as defined herein wherein m, n,
and o are each independently 1 or 2 and wherein R.sub.4, R.sub.5,
and R.sub.6 are each a C.sub.5 alkyl (i.e., tert-pentyl).
Triisopropanolamine was also present in an amount of from 0.10 wt.
% to 0.30 wt. % based on the combined weight of the phosphite
antioxidants and the triisopropanolamine.
[0137] The phenolic antioxidant included one or more phenolic
antioxidants having the structure as defined herein wherein A is a
C.sub.2 alkylene, X is --C(O)O--, R.sub.1 and R.sub.2 are a C.sub.4
alkyl (i.e., tert-butyl), and R.sub.3 is a C--C alkyl.
[0138] The lubricant composition was prepared by mixing the
antioxidants with the lubricating oil at 50.degree. C. for 30
minutes.
TABLE-US-00003 TABLE 3 Effect of Antioxidant Composition on RPVOT,
TEOST 33C, and Antiwear Performance Compar- Sample Sample Sample
Compar- ative 3 4 5 6 ative 2 Phosphite 1 0.75 0.5 0.25 0
Antioxidant (wt. %) Phenolic 0 0.25 0.5 0.75 1 Antioxidant (wt. %)
Dry RPVOT 526 587 637 580 188 (min) Expected Dry -- 441 357 272 --
RPVOT (min) % Increase -- 33.1 78.4 113.2 -- Dry RPVOT Standard 265
374 324 366 184 RPVOT (min) Expected -- 244 224 204 -- Standard
RPVOT (min) % Increase -- 53.2 44.6 79.4 -- Standard RPVOT TEOST
33C 11.9 11.8 12.0 7.6 9.7 (mg) Wear Scar 1.44 0.78 0.96 0.78 0.73
(mm) Expected -- 1.26 1.09 0.91 -- Wear Scar (mm) % Change -- -38.1
-11.9 -14.3 -- Wear Scar
[0139] As indicated in the table above, compared to an expected
oxidation induction time, the inventive samples containing bath the
phenolic antioxidant and the phosphite antioxidant demonstrate
improved antioxidation performance. In particular, compared to the
expected oxidation induction time, the actual oxidation induction
times were greater thereby demonstrating a synergistic effect when
utilizing both antioxidants in combination. Furthermore, the actual
oxidation induction time when utilizing the antioxidant composition
containing both antioxidants was greater than the oxidation
induction time when utilizing each antioxidant individually in
certain instances. Also, the amount of deposits when utilizing the
antioxidant composition also appeared to be unaffected. For
example, the amount of deposits appeared to be substantially
similar to the amount of deposits exhibited when utilizing each
antioxidant individually. In addition, the antioxidant composition
resulted in a lubricant composition that appeared to demonstrate
improved antiwear performance.
[0140] Without intending to be limited by theory, phosphite
antioxidants may generally provide improvements to antiwear
performance. In addition, when combined simply with an
alkanolamine, in certain instances, the antiwear performance may be
negatively affected. However, as indicated above, when a phosphite
antioxidant with an alkanolamine is combined with a phenolic
antioxidant, antiwear performance may not be negatively affected.
For instance, the adverse antiwear performance generally observed
with simply a phosphite antioxidant and an alkanolamine, such as
triisopropanolamine, is mitigated and a synergistic antiwear
performance is realized when the aforementioned are utilized in
combination with a phenolic antioxidant. Without intending to be
limited by theory, this may be due to the hydrogen bond(s) between
the triisopropanolamine and the phenol moiety and/or the ester
group of the phenolic antioxidant.
[0141] These and other modifications and variations of the present
invention may be practiced by those of ordinary skill in the art,
without departing from the spirit and scope of the present
invention. In addition, it should be understood that aspects of the
various embodiments may be interchanged both in whole or in part.
Furthermore, those of ordinary skill in the art will appreciate
that the foregoing description is by way of example only, and is
not intended to limit the invention so further described in such
appended claims.
* * * * *