U.S. patent application number 12/476423 was filed with the patent office on 2010-01-14 for liquid additives for the stabilization of lubricant compositions.
This patent application is currently assigned to Chemtura Corporation. Invention is credited to Jun DONG.
Application Number | 20100009875 12/476423 |
Document ID | / |
Family ID | 40887217 |
Filed Date | 2010-01-14 |
United States Patent
Application |
20100009875 |
Kind Code |
A1 |
DONG; Jun |
January 14, 2010 |
Liquid Additives for the Stabilization of Lubricant
Compositions
Abstract
A lubricating oil composition comprising: (A) a base stock; and
(B) a liquid additive package. The liquid additive package
comprises: (i) an alkylated diphenylamine; (ii) at least 5 weight %
of a phenyl naphthylamine, based on the weight of the additive
package; and (iii) a sulfur-containing phenol.
Inventors: |
DONG; Jun; (Cheshire,
CT) |
Correspondence
Address: |
Jaimes Sher
199 Chemtura Corporation, Benson Road
Middlebury
CT
06749
US
|
Assignee: |
Chemtura Corporation
Middlebury
CT
|
Family ID: |
40887217 |
Appl. No.: |
12/476423 |
Filed: |
June 2, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61080547 |
Jul 14, 2008 |
|
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Current U.S.
Class: |
508/202 ;
508/304; 508/307; 508/463; 508/561; 508/563 |
Current CPC
Class: |
C10M 141/08 20130101;
C10N 2030/10 20130101; C10N 2030/62 20200501; C10M 2219/06
20130101; C10M 2203/1006 20130101; C10M 2219/085 20130101; C10N
2040/042 20200501; C10M 2219/087 20130101; C10N 2040/12 20130101;
C10N 2070/02 20200501; C10M 2215/28 20130101; C10N 2040/04
20130101; C10M 2215/065 20130101; C10N 2040/08 20130101; C10M
2219/022 20130101; C10M 2215/064 20130101; C10N 2040/30 20130101;
C10N 2040/044 20200501; C10M 2219/00 20130101; C10M 2219/046
20130101; C10M 2219/046 20130101; C10N 2010/04 20130101; C10M
2219/046 20130101; C10N 2010/04 20130101 |
Class at
Publication: |
508/202 ;
508/563; 508/304; 508/463; 508/307; 508/561 |
International
Class: |
C10M 105/76 20060101
C10M105/76; C10M 133/12 20060101 C10M133/12; C10M 107/30 20060101
C10M107/30; C10M 105/32 20060101 C10M105/32; C10M 133/14 20060101
C10M133/14 |
Claims
1. A lubricating oil composition comprising: (A) a base stock; and
(B) a liquid additive package, wherein the additive package
comprises: (i) an alkylated diphenylamine; (ii) at least about 5
weight percent of a phenyl naphthylamine, based on the weight of
the additive package; and (iii) a sulfur-containing phenol.
2. The composition of claim 1, wherein the composition comprises
the phenyl naphthylamine in an amount ranging from about 1 to about
50 weight percent, based on the weight of the additive package.
3. The composition of claim 1, wherein the composition comprises
the phenyl naphthylamine in an amount ranging from about 10 to
about 20 weight percent, based on the weight of the additive
package.
4. The composition of claim 1, wherein the composition comprises
the sulfur-containing phenol in an amount ranging from about 5 to
about 50 weight percent, based on the weight of the additive
package.
5. The composition of claim 1, wherein the composition comprises
the sulfur-containing phenol in an amount ranging from about 10 to
about 20 weight percent, based on the weight of the additive
package.
6. The composition of claim 1, wherein the composition comprises
the sulfur-containing phenol in an amount of at least about 10
weight percent, based on the weight of the additive package.
7. The composition of claim 1, wherein the composition comprises
the alkylated diphenylamine in an amount at least about 50 weight
percent, based on the weight of the additive package.
8. The composition of claim 1, wherein the composition comprises
the alkylated diphenylamine in an amount ranging from about 50 to
about 99 weight percent, based on the weight of the additive
package.
9. The composition of claim 1, wherein the composition comprises
the alkylated diphenylamine in an amount at least about 50 wt %,
based on the weight of the additive package, and the
sulfur-containing phenol in an amount of at least about 1 wt %,
based on the weight of the additive package.
10. The composition of claim 1, wherein the composition comprises
the alkylated diphenylamine in an amount at least about 70 wt %,
based on the weight of the additive package, the phenyl
naphthylamine in an amount of at least about 10 wt % and the
sulfur-containing phenol in an amount of at least about 5 wt %,
based on the weight of the additive package.
11. The composition of claim 1, wherein the additive package has a
viscosity ranging from about 100 to about 50,000 cP at 25.degree.
C.
12. The composition of claim 1, wherein the additive package has a
viscosity ranging from about 1,000 to about 25,000 cP at 25.degree.
C.
13. The composition of claim 1, wherein the weight ratio of
alkylated diphenylamine to sulfur-containing phenol in the additive
package is at least about 6:1.
14. The composition of claim 13, wherein the weight ratio of
alkylated diphenylamine to phenyl naphthylamine in the additive
package is at least about 4:1.
15. The composition of claim 1, wherein the weight ratio of phenyl
naphthylamine to sulfur-containing phenol in the additive package
ranges from about 1:5: to about 5:1.
16. The composition of claim 1, wherein the weight ratio of
alkylated diphenylamine and phenyl naphthylamine, combined, to
sulfur-containing phenol is at least about 4:1.
17. The composition of claim 1, wherein the composition comprises
the base stock in an amount at least about 50 weight percent, based
on the weight of the lubricating oil composition, and the additive
package in an amount at least about 0.1 weight percent based on the
weight of the lubricating oil composition.
18. The composition of claim 1, wherein the composition comprises
the base stock in an amount at least about 90 weight percent, based
on the weight of the lubricating oil composition, and the additive
package in an amount at least about 0.5 weight percent based on the
weight of the lubricating oil composition.
19. The composition of claim 1, wherein the weight ratio of base
stock to additive package ranges from about 50:50 to about
99.9:0.1.
20. The composition of claim 1, wherein the base stock is selected
from a group consisting of natural lubricating oil, synthetic
lubricating oil, lard oil, vegetable oil, oleic soybean oil, high
oleic soybean oil, rapeseed oil, palm oil, jojoba oil, canola oil,
castor oil, sunflower oil, petroleum oil, mineral oil, and oils
derived from coal or shale, oils obtained by isomerization of
synthetic wax and wax, white oils, hydrocrackate oils produced by
hydrocracking the aromatic and polar components of crude oil,
polymerized and interpolymerized olefins, alkylbenzenes,
polyphenyls, alkylated diphenyl ethers, alkylated diphenyl
sulfides, alkylene oxide polymers, interpolymers, copolymers, and
derivatives thereof, esters of carboxylic acids, silicon-based
oils, liquid esters of phosphorus-containing acids, polymeric
tetrahydrofurans, poly-.alpha.-olefins and mixtures thereof.
21. The composition of claim 1, wherein the alkylated diphenylamine
is selected from a group consisting of diphenylamine, monoalkylated
diphenylamine, dialkylated diphenylamine, trialkylated
diphenylamine, 3-hydroxydiphenylamine, 4-hydroxydiphenylamine,
mono- and/or di-tert-butyl diphenylamine, mono- and or
di-diheptyldiphenylamine, mono- and/or di-octyldiphenylamine,
di-octyl diphenylamine, mono- and/or dononyldiphenylamine, mono-
and/or di-dodecyl diphenylamine, hexadecyl diphenylamine, eicosenyl
diphenylamine, tetracosenyl diphenylamine, octacosenyl
diphenylamine, polyisobutyl diphenylamine, mono and/or
di-(.alpha.-methylstyryl)diphenylamine, mono- and/or
di-styryidiphenylamine, 4-(p-toluenesulfonoamido)diphenylamine,
4-isopropoxydiphenylamine, t-octylated N-phenyl-1-naphthylamine,
mixtures of mono- and di-alkylated t-butyl-t-octyldiphenylamine and
mixtures thereof.
22. The composition of claim 1, wherein the sulfur-containing
phenol is represented by Formula I ##STR00009## wherein R.sub.1 is
a sulfur-containing alkyl, a sulfur-containing aryl group, a
sulfur-containing alkene or a sulfur-containing carboxylic acid;
and wherein R.sub.2 and R.sub.3 are alkyl, aryl or hydrogen.
23. The composition of claim 1, wherein the base stock is a food
grade lubricant.
24. The composition of claim 1, wherein the composition exhibits a
pressurized differential scanning calorimeter oxidation induction
time at least about 25 minutes.
25. The composition of claim 1, wherein the composition exhibits a
pressurized differential scanning calorimeter oxidation induction
time of about 40 minutes.
26. The composition of claim 1, wherein the composition has a
Thermo-Oxidation Engine Oil Simulation Test value of less than
about 50 milligrams.
27. The composition of claim 1, wherein the composition has a
Thermo-Oxidation Engine Oil Simulation Test value of less than
about 40 milligrams.
28. The composition of claim 1, wherein the composition comprises:
(A) about 99 weight percent of the base stock, based on the weight
of the lubricating oil composition; and (B) about 1 weight percent
of the additive package, based on the weight of the lubricating oil
composition, wherein the additive package comprises: (i) about 70
weight percent of alkylated diphenylamine, based on the weight of
the additive package; (ii) about 15 weight percent of
phenyl-.alpha.-naphthylamine, based on the weight of the additive
package; and (iii) about 15 weight percent of sulfur-containing
phenol, based on the weight of the additive package.
29. A liquid additive package comprising: (A) an alkylated
diphenylamine; (B) at least 5 weight percent of a phenyl
naphthylamine, based on the weight of the additive package; and (C)
a sulfur-containing phenol.
30. The additive package of claim 29, wherein the composition
comprises the phenyl naphthylamine in an amount ranging from about
1 to about 50 weight percent, based on the weight of the additive
package.
31. The additive package of claim 29, wherein the composition
comprises the phenyl naphthylamine in an amount ranging from about
10 to about 20 weight percent, based on the weight of the additive
package.
32. The additive package of claim 29, wherein the composition
comprises the sulfur-containing phenol in an amount ranging from
about 5 to about 50 weight percent, based on the weight of the
additive package.
33. The additive package of claim 29, wherein the composition
comprises the sulfur-containing phenol in an amount ranging from
about 10 to about 20 weight percent, based on the weight of the
additive package.
34. The additive package of claim 29, wherein the composition
comprises the sulfur-containing phenol in an amount of at least
about 10 weight percent, based on the weight of the additive
package.
35. The additive package of claim 29, wherein the composition
comprises the alkylated diphenylamine in an amount at least about
50 weight percent, based on the weight of the additive package.
36. The additive package of claim 29, wherein the composition
comprises the alkylated diphenylamine in an amount ranging from
about 50 to about 99 weight percent, based on the weight of the
additive package.
37. The additive package of claim 29, wherein the composition
comprises the alkylated diphenylamine in an amount at least about
50 wt %, based on the weight of the additive package, and the
sulfur-containing phenol in an amount of at least about 1 wt %,
based on the weight of the additive package.
38. The additive package of claim 29, wherein the composition
comprises the alkylated diphenylamine in an amount at least about
70 wt %, based on the weight of the additive package, the phenyl
naphthylamine in an amount of at least about 10 wt % and the
sulfur-containing phenol in an amount of at least about 5 wt %,
based on the weight of the additive package.
39. The additive package of claim 29, wherein the additive package
has a viscosity ranging from about 100 to about 50,000 cP at
25.degree. C.
40. The additive package of claim 29, wherein the additive package
has a viscosity ranging from about 1,000 to about 25,000 cP at
25.degree. C.
41. The additive package of claim 29, wherein the weight ratio of
alkylated diphenylamine to sulfur-containing phenol in the additive
package is at least about 6:1.
42. The additive package of claim 41, wherein the weight ratio of
alkylated diphenylamine to phenyl naphthylamine in the additive
package is at least about 4:1.
43. The additive package of claim 29, wherein the weight ratio of
phenyl naphthylamine to sulfur-containing phenol in the additive
package ranges from about 1:5: to about 5:1.
44. The additive package of claim 29, wherein the weight ratio of
alkylated diphenylamine and phenyl naphthylamine, combined, to
sulfur-containing phenol is at least about 4:1.
45. A method of producing a liquid additive package comprising:
combining (i) alkylated diphenylamine; (ii) at least about 5 weight
percent of a phenyl naphthylamine, based on the weight of the
additive package; and (iii) a sulfur-containing phenol.
46. The method of claim 45, wherein the combining is performed
under nitrogen.
47. The method of claim 45, wherein the ratio of phenyl
naphthylamine to alkylated diphenylamine ranges from about 1:20 to
about 1:3.
48. A method of producing a lubricating oil composition comprising:
(A) providing a base stock; and (B) blending with the base stock a
liquid additive package comprising: (i) alkylated diphenylamine;
(ii) at least 5 weight percent of a phenyl naphthylamine, based on
the weight of the additive package; and (iii) a sulfur-containing
phenol.
49. The method of claim 48, wherein the base stock base stock is in
an amount at least about 90 weight percent, based on the weight of
the lubricating oil composition, and the additive package is in an
amount at least about 0.5 weight percent based on the weight of the
lubricating oil composition.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to U.S. Provisional
Application No. 61/080,547, filed on Jul. 14, 2008, the entirety of
which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to lubricating oil
compositions. More specifically to lubricating oil compositions
comprising additive packages for reducing oxidative
deterioration.
BACKGROUND OF THE INVENTION
[0003] Lubricants, such as those used in a variety of machinery,
are susceptible to oxidative deterioration during storage,
transportation, and usage, particularly when such lubricants are
exposed to high temperatures and iron catalytic environments, which
greatly promote the oxidation of the lubricant. This oxidation, if
not controlled, contributes to the formation of corrosive acidic
products, sludge, varnishes, resins, and other oil-insoluble
products and may lead to a loss of designated physical and
tribological properties of the lubricants. These oxidation products
may lead to the formation of harmful deposits on critical engine
parts, such as the pistons, piston liners, valves, and valve
lifters.
[0004] It is therefore a common practice to include deposit-control
compounds and/or additives, e.g., antioxidant additives, in
lubricants to prevent, at least to some extent, oxidation, thereby
extending the useful life of the lubricants. One of these
antioxidant additives is alkylated diphenylamine (ADPA), which has
been used extensively because of its performance and low cost.
However, driven by escalating performance and environmental
requirements in recent years, there has been a general trend in the
industry toward machinery being built smaller yet operating at
higher speeds and higher operating temperatures. As such, more
output and higher fuel economy are achieved. However, under such
operating conditions, the thermal and oxidative stress on the
lubricants has become severe that conventional ADPA antioxidants
insufficiently stabilize the lubricants.
[0005] Lubricant compositions containing various antioxidants are
widely known in the art. As an example, U.S. Pat. No. 6,326,336 to
Gatto, et al. (herinafter "Gatto") discloses a turbine lubricating
oil comprising (A) an amine antioxidant selected from the group
consisting of alkylated diphenylamines, phenylnaphthylamines and
mixtures thereof; (B) sulfur-containing additives selected from the
group consisting of sulfurized olefins, sulfurized fatty acids,
ashless dithiocarbamates, tertaalkylthiuram disulfides and mixtures
thereof, and (C) a base oil. According the Gatto, such a
composition provides superior oxidation protection and acceptable
sludge control in turbine oils formulated with Group II or higher
base oils. An important criterion for selecting the concentration
of sulfur-containing additive is the sulfur content of the additive
package. According to Gatto, the sulfur-containing additive should
deliver between 0.005 wt. % and 0.07 wt. % of sulfur to the
finished turbine oil. However, Gatto utilizes only sulfurized
olefins, sulfurized fatty acids, ashless dithiocarbamates,
tetraalkylthiuram disulfides and mixtures thereof. Gatto states
that there are a number of problems that may be associated with the
use of hindered phenols. Gatto states that hindered phenols under
high temperatures can dealkylate and produce free phenol and that
water extractablility of certain water soluble phenols is another
potential problem. Thus, Gatto states, a phenol-free formulation
may be desired.
[0006] U.S. Pat. No. 5,091,099 discloses to a phosphite-free
lubricating oil composition which comprises a) a mineral oil or a
synthetic oil or a mixture thereof; and b) a mixture containing at
least one aromatic amine of the formula (I),
##STR00001##
and at least one phenol of the formula (II)
##STR00002##
and the compounds are present in the mixture in a ratio of 2 to 6
parts by weight of the aromatic amine(s) of the formula (I) to 1
part by weight of the phenol(s) of the formula II.
[0007] U.S. Pat. No. 5,523,007 discloses a lubricating oil
composition comprising a diesel engine oil and, as antioxidant, a
compound of formula I
##STR00003##
wherein X is
##STR00004##
and R is a straight chain or branched alkyl radical of the formula
C.sub.nH.sub.2n+1, wherein n is an integer from 8 to 22. Such a
phenol may contain sulfur, but weight percentages and relationships
to other components are not taught.
[0008] One potential antioxidant that can be utilized to achieve
superior performance in antioxidant packages is phenyl
naphthylamine (PNA). However, PNA is typically sold as a solid at
room temperature, and, as such, is not easily blended into the base
oil.
[0009] Even in view of these known lubricant compositions, the need
remains for a cost-effective antioxidant package that provides
improved antioxidant stability and blends easily with base
stocks.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The present invention generally relates to lubricating oil
compositions that may be utilized in high temperature environments.
Typically, such high temperature environments promote oxidative
deterioration of the lubricants. The lubricating oil compositions
of the present invention are less susceptible to such oxidative
deterioration, i.e., they are more stable, and, as such, provide
improved physical and tribological properties at high
temperatures.
[0011] In one embodiment of the invention, the composition
comprises a liquid additive package having at least about 1 weight
percent (wt %), e.g., at least about 3 wt %, at least about 5 wt %,
at least about 7 wt %, at least about 10 wt %, or at least about 15
wt %, of a phenyl naphthylamine (PNA), e.g.,
phenyl-a-naphthylamine, and a base stock. In terms of ranges, the
PNA may be present in amounts ranging from about 1 wt % to about 50
wt %, e.g., from about 2 wt % to about 50 wt %, from about 3 wt %
to about 40 wt %, from about 5 wt % to about 30 wt %, or from about
5 wt % to about 30 wt %. Such additive packages, when combined with
a suitable base stock, reduces the amount of harmful deposits
resulting from oxidation of the lubricating oil composition as
compared to additive packages with less than 5 wt % PNA.
[0012] Preferably, the liquid additive package, e.g., liquid
antioxidant additive package, comprises a diphenylamine, e.g., an
alkylated diphenylamine (ADPA), and at least about 5 wt % PNA.
Typically, the PNA is solid at room temperature and is difficult to
dissolve in liquids, e.g., ADPA or base stocks. In a preferred
embodiment of the invention, the PNA is combined with ADPA, e.g.,
under heat, e.g. at about 150.degree. C., about 100.degree. C.,
about 65.degree. C., or about 50.degree. C., and/or under nitrogen
or a similar inert atmosphere until a homogeneous mixture is
achieved. The mixture is a stable liquid at room temperature. The
ADPA and the PNA may be mixed for about 10 to about 20 minutes,
e.g. about 12 to about 18 minutes, or about 14 to about 16 minutes.
It should be noted that the time periods listed above are merely
exemplary and that the time will vary as the quantities of each of
the materials vary. In one embodiment, the resultant composition is
dark reddish in color and has a viscosity of less than about 50,000
cP, e.g., less than about 30,000 cP or less than about 20,000 cP,
as measured at 25.degree. C. In terms of ranges, the viscosity of
the composition ranges from about 100 to about 100,000 cP, e.g.,
from about 100 to about 50,000 cP, or from about 1,000 to about
25,000 cP, as measured at 25.degree. C.
[0013] In one embodiment of the present invention, the lubricant
oil composition, when combined with a poly-a-olefin base stock at a
weight ratio of about 99: 1, base stock to additive package, shows
an oxidation induction time (OIT), as tested under the pressurized
differential scanning calorimeter (PDSC) conditions shown in TABLE
1, of at least about 25 minutes, e.g., at least about 38 minutes,
at least about 40 minutes, at least about 50 minutes or at least
about 75 minutes. This is a significant improvement over a similar
lubricant oil composition comprising the same poly-.alpha.-olefin
base stock and pure ADPA, which, in similar testing, shows an
oxidation time of 28.6 minutes. It should be noted that the test
parameters under which the PDSC is operated may affect the OIT of
the sample. For example, the a sample tested at 160.degree. C. may
have a longer OIT than a similar sample tested at 185.degree.
C.
TABLE-US-00001 TABLE 1 Test Parameters PDSC Test Conditions
Isothermal Temperature 185.degree. C. O.sub.2 Gas Pressure 500 psi
O.sub.2 Gas Flow Rate Through Cell 100 ml/min, continuous Catalyst
50 ppm of Iron Sample Holder Open Aluminum Pan Sample size 1.0-2.0
mg Induction Time Enthalpy Change
[0014] In another embodiment of the invention, the additive package
comprises ADPA, PNA and a sulfur-containing phenol. Typically, the
sulfur-containing phenol is solid at room temperature. However,
sulfur-containing phenols that are liquids at room temperature may
be utilizedas well. In one embodiment, the combination of the ADPA,
PNA and sulfur-containing phenol forms a clear liquid. In another
embodiment, the combination of the ADPA, PNA and sulfur-containing
phenol produces an additive package that significantly improves the
oxidative stability and reduces the amount of Mid-High Temperature
Thermo-Oxidation Engine Oil Simulation Test (TEOST MHT, ASTM D
7097) deposits (see below) over that of ADPA alone. Such an
additive package, when blended (at a wt % of about 1 wt %) into an
engine oil containing an API Group II base stock demonstrated an
OIT of about 40 minutes and showed deposits of 37 milligrams (mg).
In one embodiment of the invention, the lubricant oil composition
has a TEOST MHT value of less than about 60 mg, e.g., less than
about 50 mg, less than about 40 mg or less than about 20 mg. It
should be noted that an additive package of pure ADPA yields a
TEOST MHT value of about 55 mg, pure PNA yields a TEOST MHT value
of about 80 mg, and pure sulfur-containing phenol yields a TEOST
MHT value of about 63 mg. Hence, a TEOST MHT value of less than 55
mg, for the lubricant composition, is surprising and
unexpected.
[0015] In one preferred embodiment of the invention, the ADPA is
present in an amount of at least about 50 wt %, e.g., at least
about 60 wt %, or at least about 70 wt %, based on the weight of
the additive package. In terms of ranges, preferably, the ADPA is
present in an amount ranging from about 50 to about 99 wt %, e.g.,
from about 60 to about 99 wt %, from about 70 to about 95 wt %, or
from about 70 to about 90 wt %, based on the weight of the additive
package.
[0016] In one embodiment of the invention, the PNA is present in an
amount of at least about 1 wt % e.g., at least about 3 wt %, at
least about 5 wt %, at least about 7 wt %, at least about 10 wt %,
at least about 15 wt %, at least about 20 wt %, at least about 25
wt %, or at least about 50 wt %, based on the weight of the
additive package. In terms of ranges, the PNA is present in an
amount ranging from about 1 wt % to about 50 wt %, e.g., from about
2 wt % to about 50 wt %, from about 5 wt % to about 50 wt %, from
about 3 wt % to about 40 wt %, from about 5 wt % to about 30 wt %,
or from about 5 wt % to about 30 wt %, based on the weight of the
additive package. Additive packages having the above-mentioned
amounts of PNA demonstrate results that are surprising and
unexpected when compared to the results of additive packages
utilizing less than 50 wt %, e.g., less than 25 wt %, less than 20
wt %, less than 15 wt %, less than 10 wt %, less than 5 wt % or
less than 1 wt %.
[0017] In another embodiment of the invention, the
sulfur-containing phenol is present in an amount of at least about
1 wt % e.g., at least about 5 wt %, at least about 10 wt %, at
least about 15 wt %, at least about 20 wt %, at least about 25 wt %
or at least about 50 wt %, based on the weight of the additive
package. In terms of ranges, the sulfur-containing phenol is
present in an amount ranging from about 5 to about 50 wt %, e.g.,
from about 10 wt % to about 25 wt %, from about 10 wt % to about 20
wt % or from about 10 wt % to about 15 wt %, based on the weight of
the additive package.
[0018] In one embodiment of the invention, the ADPA is present in
an amount of at least 50 wt %, e.g., at least 60 wt %, or at least
70 wt, the PNA is present in an amount of at least 1 wt % e.g., at
least 5 wt %, at least 10 wt %, at least 15 wt %, at least 20 wt %,
at least 25 wt % or at least 50 wt %, and the sulfur-containing
phenol is present in an amount of at least 1 wt % e.g., at least 5
wt %, at least 10 wt %, at least 15 wt %, at least 20 wt %, at
least 25 wt % or at least 50 wt %, all wt % being based on the
weight of the additive package.
[0019] In a preferred embodiment of the invention, the ADPA is
present in an amount of about 70 wt % .+-.10 wt %, e.g., .+-.5 wt
%, .+-.3 wt % or .+-.1 wt %; the PNA is present in an amount of
about 15 wt % .+-.14 wt %, e.g., .+-.10 wt %, .+-.5 wt %, .+-.3 wt
% or .+-.1 wt %; and the sulfur-containing phenol is present in an
amount of about 15 wt % .+-.10 wt %, e.g., .+-.5 wt %, .+-.3 wt %
or .+-.1 wt %; all wt % being based on the weight of the additive
package. Additional preferred embodiments utilize the wt %
combinations of ADPA, PNA and sulfur-containing phenol listed in
TABLE 2. Each of the weight percentages listed for these
embodiments can vary by .+-.10 wt %, e.g., .+-.5 wt %, .+-.3 wt %,
.+-.2 wt % or .+-.1 wt %.
TABLE-US-00002 TABLE 2 Wt % Sulfur- Exemplary containing
Combination Wt % ADPA Wt % PNA phenol 1 60 20 20 2 60 10 30 3 60 30
10 4 60 15 25 5 60 25 15 6 70 10 20 7 70 20 10 8 70 5 25 9 70 25 5
10 80 10 10 11 80 5 15 12 80 15 5 13 90 5 5
[0020] In one embodiment of the invention, the weight ratio of ADPA
to sulfur-containing phenol in the additive package is at least
about 3:1, e.g., at least about 6:1 or at least about 10:1.
[0021] In another embodiment of the invention, the weight ratio of
PNA to sulfur-containing phenol in the additive package ranges from
about 1:10 to about 10:1, e.g., from about 1:8 to about 8:1, from
about 1:5 to about 5:1 or from about 1:3 to about 3:1.
[0022] In another embodiment of the invention, the weight ratio of
ADPA and PNA, combined to sulfur-containing phenol is at least
about 2:1, e.g., at least about 3:1, at least about 4:1, at least
about 5:1 or at least about 10:1.
[0023] In another embodiment of the invention, the weight ratio of
ADPA to PNA in the additive package is at least about 2: 1, e.g.,
at least about 3: 1, at least about 4: 1, at least about 5:1 or at
least about 10:1. In terms of ranges, the weight ratio ranges from
about 3:1 to about 20: 1, e.g. from about 3:1 to about 15:1 or from
about 3:1 to about 10:1.
[0024] In one embodiment, the base stock is present in an amount of
at least about 50 wt %, e.g. at least about 75 wt %, at least about
95 wt % or at least about 99 wt %, based on the weight of the
lubricating oil composition (including the additive package).
[0025] In one embodiment, the additive package is present in an
amount of at least about 0.05 wt %, e.g., at least about 0.5 wt %,
at least about 1 wt % or at least about 10 wt %, based on the
weight of the lubricating oil composition.
[0026] In terms of ranges, the ratio of base stock to additive
package ranges from about 50:50 to about 99.95:0.05, e.g. from
about 75:25 to about 99.9:0.1, from about 90:10 to about 99:1 or
from about 95:5 to about 99:1. In a preferred embodiment of the
invention, the lubricating oil composition comprises about 99 wt %
of the base stock combined with about 1 wt % of the additive
package based on the total weight of the lubricating oil.
[0027] The additive packages of the present invention are
especially useful as components in combination with many potential
base stocks. The additive packages may be included in a variety of
oils with lubricating viscosity, including natural and synthetic
lubricating oils and mixtures thereof. As an example, the additive
packages are included in crankcase lubricating oils for
spark-ignited and compression-ignited internal combustion engines.
The additive packages can also be used, for example, with gas
engine lubricants, turbine lubricants, automatic transmission
fluids, gear lubricants, compressor lubricants, metal-working
lubricants, hydraulic fluids, and other lubricating oil and grease
compositions. In one embodiment of the invention, the additive
package is utilized in the preparation of lubricants that may have
food contact e.g., incidental food contact. More specifically, the
additive package may be utilized with an Hi food grade base
stock.
[0028] In one embodiment, the additive packages are combined with a
grease or a combination of greases. Greases are often used in
applications having high pressures and slow speed. Such
applications include, but are not limited to, continuous casting
operations.
[0029] In one embodiment of the invention, the ADPA of the present
invention comprises ADPAs of the Formula I:
##STR00005##
wherein R.sub.1 and R.sub.2 are independently selected from the
group consisting of linear or branched C.sub.1-C.sub.20 alkyl,
substituted or unsubstituted C.sub.3-C.sub.20 cycloalkyl.
[0030] In one embodiment of the invention, R.sub.1 and R.sub.2 may
be the same substituent. In one embodiment of the invention,
R.sub.1 or R.sub.2 are both not hydrogen.
[0031] Representative examples of alkyl groups for use herein for
R.sub.1 and R.sub.2, include, for example, a straight or branched
hydrocarbon chain radical containing from 1 to 20 carbon atoms,
e.g., methyl, ethyl, n-propyl, 1-methylethyl (isopropyl), n-butyl,
isobutenyl, n-pentyl, etc., mixtures and isomers thereof, and the
like.
[0032] Representative examples of cycloalkyl groups for use herein
for R.sub.1 and R.sub.2 include, for example, substituted or
unsubstituted rings containing from about 5 to about 20 carbon
atoms, e.g., cyclopentyl, cyclohexyl, n-methyl-cyclohexyl,
n-dimethyl-cyclohexyl, n-ethyl-cyclohexyl, cycloheptyl, cyclooctyl,
etc., mixtures and thereof, and the like.
[0033] In another embodiment of the invention, the ADPA is further
alkylated with more than two substituent groups. In another
embodiment of the invention, the ADPA is alkylated with only one
substituent group.
[0034] Preferred ADPAs that can be employed in the practice of the
present invention include, for example, nonylated diphenylamine,
octylated diphenylamine (e.g., di(octylphenyl)amine), styrenated
diphenylamine, octylated styrenated diphenylamine, butylated
octylated diphenylamine, diphenylamine, butyldiphenylamine,
dibutyldiphenylamine, octyldiphenylamine, dioctyldiphenylamine,
nonyldiphenylamine, dinonyldiphenylamine, heptyldiphenylamine,
diheptyldiphenylamine, methylstyryldiphenylamine mixed butyl/octyl
alkylated diphenylamines, mixed butyl/styryl alkylated
diphenylamines, mixed nonyl/ethyl alkylated diphenylamines, mixed
octyl/styryl alkylated diphenylamines, mixed ethyl/methylstyryl
alkylated diphenylamines, tert-butyl diphenylamine, di-tert-butyl
diphenylamine, mono-octyl diphenylamine, dodecyl diphenylamine,
hexadecyl diphenylamine, eicosenyl diphenylamine, tetracosenyl
diphenylamine, octacosenyl diphenylamine, polyisobutyl
diphenylamine and mixtures thereof.
[0035] Preferred commercially produced ADPAs that can be utilized
in the present invention include, for example, Irganox.RTM. L06,
Irganox.RTM. L57, and Irganox.RTM. L67 from Ciba Specialty
Chemicals; Naugalube.RTM. AMS, Naugalube.RTM. 438, Naugalube.RTM.
438R, Naugalube.RTM. 438L, Naugalube.RTM. 500, Naugalube.RTM. 640,
and Naugalube.RTM.680 from Chemtura Corporation; Goodrite.RTM.
3123, Goodrite.RTM. 3190X36, Goodrite.RTM. 3127, Goodrite.RTM.
3128, Goodrite.RTM.33185X1, Goodrite.RTM.3190, Goodrite.RTM.
3190X29, Goodrite.RTM.33190X40, and Goodrite.RTM. 3191,
Goodrite.RTM.3192 from BFGoodrich Specialty Chemicals; HiTEC.RTM.
569 antioxidant and HiTEC.RTM. 4793 antioxidant available from
Ethyl Corporation; Vanlube.RTM. DND, Vanlube.RTM.NA,
Vanlube.RTM.PNA, Vanlube.RTM. SL, Vanlube.RTM. SLHP, Vanlube.RTM.
SS, Vanlube.RTM.81, Vanlube.RTM.848, and Vanlube.RTM. 849 and
Vanlube.RTM. 961 from R. T. Vanderbilt Company, Inc. In one
embodiment of the invention, the additive package comprises a
mixture of two or more ADPAs selected from the structures and
compounds identified above. Exemplary mixtures are mixed mono- and
di-octyl diphenylamines (DPAs), mixed mono and di-nonyl DPAs, mixed
mono and di-styryl DPAs, mixed butyl/styryl alkylated DPAs, mixed
octyl/styryl alkylated DPAs and mixed butyl/octyl alkylated
DPAs.
[0036] In one embodiment of the present invention, the PNA
comprises phenyl-.alpha.-naphthylamine. In another embodiment of
the invention, the PNA comprises phenyl-p-naphthlyamine.
[0037] In one embodiment of the present invention, the PNA
comprises one or more PNAs of formula II:
##STR00006##
[0038] In another embodiment of the present invention, the PNA
comprises one or more PNAs of Formula III:
##STR00007##
[0039] In another embodiment of the present invention, the PNA
comprises a blend of PNAs of the previous two formulae.
[0040] In another embodiment of the invention, the PNA is
substituted, e.g., alkylated, with one or more substituent groups.
The potential substituent groups include, for example, the
substituents mentioned above as candidates for R.sub.1 and R.sub.2.
In one embodiment, the phenyl rings of Formula II or Formula III
are substituted at the ortho, para or meta positions.
[0041] Preferred PNAs that can be employed in the present invention
include, for example, octyl alkylated phenyl-.alpha.-naphthylamine,
docecyl phenyl-.alpha.-naphthylamines and mixed alkylated
phenyl-.alpha.-naphthylamines. Examples of commercially produced
substituted PNAs are Naugalube.RTM. PANA and Irganox.RTM. L06.
[0042] Preferred commercially produced PNAs that can be utilized in
the present invention include, for example, Naugard.RTM. PANA.
[0043] In one embodiment of the invention, there is a composition
comprising a mixture of two or more PNAs selected from the
structures and compounds identified above.
[0044] In one embodiment of the invention, the sulfur-containing
phenol comprises sulfur-containing phenols of Formula IV
##STR00008##
[0045] wherein R.sub.3 is a sulfur-containing alkyl or aryl group,
or a sulfur-containing alkene or carboxylic acid; and
[0046] wherein R.sub.4 and R.sub.5 are alkyl or aryl.
[0047] Preferred sulfur-containing phenols that can employed in the
present invention include, for example, 2,2'-thiodiethylene
bis(3,5,-di-t-butyl-4-hydroxyphenyl)propionate,
2,2'-thiobis(4-methyl-6-t-butyl-phenol),
4,4'-thiobis(2-t-butyl-5-methylphenol) and
iso(C10-C14)alkyl(3,5-di-tert-butyl-4-hydroxyphenyl)methylthioacetate.
[0048] Preferred commercially produced sulfur-containing phenols
that can be utilized in the present invention include, for example,
Naugalube.RTM. 15, Naugalube.RTM. 16 and Naugalube.RTM. 18 from
Chemtura Corporation; Irganox.RTM.L115, Irganox.RTM.L118,
Irganox.RTM.L1035, Irganox.RTM.L1081 and Irganox.RTM.L415 for Ciba
Specialty chemicals. In one embodiment of the invention, the
additive package is prepared by mixing Naugalube.RTM. 438L with
Naugard.RTM. PNA and a sulfur-containing phenol. Mixing is carried
out at 65.degree. C. and under nitrogen protection. The mixing may
be carried out for at least 5 minutes, e.g., at least 10 minutes,
at least 15 minutes, at least 25 minutes, or at least 60 minutes.
It should be appreciated by those of ordinary skill in the art that
the mixing time will vary based on the quantities of each of the
materials. The resultant mixture was a free-flowing liquid at room
temperature having a viscosity, measured at 40.degree. C., of less
than about 100,000 cP, e.g., less than about 50,000 cP, less than
about 40,000 cP, less than about 25,000 cP or less than about
10,000 cP. In other embodiments, the resultant mixture was dark
reddish in color.
[0049] In a preferred embodiment of the invention, the additive
package comprises nonylated diphenylamine, octyl
phenyl-alpha-naphthylamine and 2,2'-thiodiethylene bis
(3,5,-di-t-butyl-4-hydroxyphenyl)propionate. In another preferred
embodiment of the invention, the additive package comprises butyl
and octylated diphenylamine, octyl alkylated
phenyl-alpha-naphthylamine and
2,2'-thiobis(4-methyl-6-t-butyl-phenol). In another preferred
embodiment of the invention, the additive package comprises octyl
and styrenated diphenylamine, mixed alkylated
phenyl-.alpha.-naphthylamines and 2,2'-thiodiethylene bis
(3,5,-di-t-butyl-4-hydroxyphenyl)propionate.
[0050] Additional embodiments utilize the combinations of ADPA, PNA
and sulfur-containing phenol listed in TABLE 3. This listing is not
exclusive of all preferred embodiments.
TABLE-US-00003 TABLE 3 Exemplary Combination ADPA PNA
Sulfur-containing Phenol 14 Mixed mono- and Octyl alkylated
2,2'-thiodiethylene bis (3,5,- di-octyl DPAs phenyl-.alpha.-
di-t-butyl-4- naphthylamine hydroxyphenyl)propionate 15 Mixed mono-
and Dodecyl phenyl-.alpha.- 2,2'-thiodiethylene bis (3,5,- di-octyl
DPAs naphthylamine di-t-butyl-4- hydroxyphenyl)propionate 16 Mixed
mono- and Octyl alkylated 2,2'-thiodiethylene bis (3,5,- di-nonyl
DPAs phenyl-.alpha.- di-t-butyl-4- naphthylamine
hydroxyphenyl)propionate 17 Mixed mono- and Dodecyl phenyl-.alpha.-
2,2'-thiodiethylene bis (3,5,- di-nonyl DPAs naphthylamine
di-t-butyl-4- hydroxyphenyl)propionate 18 Mixed mono- and Octyl
alkylated 2,2'-thiodiethylene bis (3,5,- di-styryl DPAs
phenyl-.alpha.- di-t-butyl-4- naphthylamine
hydroxyphenyl)propionate 19 Mixed mono- and Dodecyl phenyl-.alpha.-
2,2'-thiodiethylene bis (3,5,- di-styryl DPAs naphthylamine
di-t-butyl-4- hydroxyphenyl)propionate 20 Mixed butyl/styryl Octyl
alkylated 2,2'-thiodiethylene bis (3,5,- alkylated DPAs
phenyl-.alpha.- di-t-butyl-4- naphthylamine
hydroxyphenyl)propionate 21 Mixed butyl/styryl Dodecyl
phenyl-.alpha.- 2,2'-thiodiethylene bis (3,5,- alkylated DPAs
naphthylamine di-t-butyl-4- hydroxyphenyl)propionate 22 Mixed
octyl/styryl Octyl alkylated 2,2'-thiodiethylene bis (3,5,-
alkylated DPAs phenyl-.alpha.- di-t-butyl-4- naphthylamine
hydroxyphenyl)propionate 23 Mixed octyl/styryl Dodecyl
phenyl-.alpha.- 2,2'-thiodiethylene bis (3,5,- alkylated DPAs
naphthylamine di-t-butyl-4- hydroxyphenyl)propionate 24 Mixed
butyl/styryl Octyl alkylated 2,2'-thiodiethylene bis (3,5,-
alkylated DPAs phenyl-.alpha.- di-t-butyl-4- naphthylamine
hydroxyphenyl)propionate 25 Mixed butyl/styryl Dodecyl
phenyl-.alpha.- 2,2'-thiodiethylene bis (3,5,- alkylated DPAs
naphthylamine di-t-butyl-4- hydroxyphenyl)propionate
[0051] Exemplary ADPA, PNA and sulfur-containing phenol candidates
are listed in TABLE 4. This listing is not exclusive.
TABLE-US-00004 TABLE 4 ADPA PNA Sulfur-containing Phenol Mixed mono
and Phenyl-.alpha.- 2,2'-thiodiethylene bis- di-octyl DPAs
naphthylamine (3,5,-di-tbutyl-4- hydroxyphenyl)propionate Mixed
mono and Octyl phenyl-.alpha.- 2,2'-thiobis(4-methyl-6-t- di-nonyl
DPAs naphthylamine butyl-phenol Mixed mono and Dodecyl
phenyl-.alpha.- 4,4'-thiobis(2-t-butyl-5- di-styryl DPAs
naphthylamine methylphenol Mixed butyl/styryl Iso(C10-C14)alkyl
(3,5-di- alkylated DPAs tert-butyl-4-hydroxyphenyl) Mixed
octyl.styryl methylthioacetate alkylated DPAs Mixed butyl/octyl
alkylated DPAs
[0052] Additional additives may be incorporated in the compositions
of the invention to enable them to meet particular requirements.
Examples of additives that may be included in the lubricating oil
compositions are dispersants, detergents, metal rust inhibitors,
viscosity index improvers, corrosion inhibitors, oxidation
inhibitors, friction modifiers, other dispersants, anti-foaming
agents, anti-wear agents and pour point depressants. Some are
discussed in further detail below.
[0053] Lubricating oil compositions of the present invention can
further contain one or more ashless dispersants, which effectively
reduce formation of deposits upon use in gasoline and diesel
engines, when added to lubricating oils. Ashless dispersants useful
in the compositions of the present invention comprise an oil
soluble polymeric long chain backbone having functional groups
capable of associating with particles to be dispersed. Typically,
such dispersants comprise amine, alcohol, amide or ester polar
moieties attached to the polymer backbone, often via a bridging
group. The ashless dispersant can be, for example, selected from
oil soluble salts, esters, amino-esters, amides, imides, and
oxazolines of long chain hydrocarbon-substituted mono- and
polycarboxylic acids or anhydrides thereof; thiocarboxylate
derivatives of long chain hydrocarbons; long chain aliphatic
hydrocarbons having polyamine moieties attached directly thereto;
and Mannich condensation products formed by condensing a long chain
substituted phenol with formaldehyde and polyalkylene
polyamine.
[0054] Preferred dispersants include polyamine-derivatized poly
alpha-olefin, dispersants, particularly ethylene/butene
alpha-olefin and polyisobutylene-based dispersants. Particularly
preferred are ashless dispersants derived from polyisobutylene
substituted with succinic anhydride groups and reacted with
polyethylene amines, e.g., polyethylene diamine, tetraethylene
pentamine; or a polyoxyalkylene polyamine, e.g., polyoxypropylene
diamine, trimethylolaminomethane; a hydroxy compound, e.g.,
pentaerythritol; and combinations thereof. One particularly
preferred dispersant combination is a combination of (A)
polyisobutylene substituted with succinic anhydride groups and
reacted with (B) a hydroxy compound, e.g., pentaerythritol; (C) a
polyoxyalkylene polyamine, e.g., polyoxypropylene diamine, or (D) a
polyalkylene diamine, e.g., polyethylene diamine and tetraethylene
pentamine using about 0.3 to about 2 moles of (B), (C) and/or (D)
per mole of (A). Another preferred dispersant combination comprises
a combination of (A) polyisobutenyl succinic anhydride with (B) a
polyalkylene polyamine, e.g., tetraethylene pentamine, and (C) a
polyhydric alcohol or polyhydroxy-substituted aliphatic primary
amine, e.g., pentaerythritol or trismethylolaminomethane, as
described in U.S. Pat. No. 3,632,511.
[0055] Another class of ashless dispersants comprises Mannich base
condensation products. Generally, these products are prepared by
condensing about one mole of an alkyl-substituted mono- or
polyhydroxy benzene with about 1 to 2.5 moles of carbonyl
compound(s) (e.g., formaldehyde and paraformaldehyde) and about 0.5
to 2 moles of polyalkylene polyamine, as disclosed, for example, in
U.S. Pat. No. 3,442,808. Such Mannich base condensation products
can include a polymer product of a metallocene catalyzed
polymerization as a substituent on the benzene group, or can be
reacted with a compound containing such a polymer substituted on a
succinic anhydride in a manner similar to that described in U.S.
Pat. No. 3,442,808. Examples of functionalized and/or derivatized
olefin polymers synthesized using metallocene catalyst systems are
described in the publications identified supra.
[0056] The dispersant can be further post treated by a variety of
conventional post treatments such as boration, as generally taught
in U.S. Pat. Nos. 3,087,936 and 3,254,025. Boration of the
dispersant is readily accomplished by treating an acyl
nitrogen-containing dispersant with a boron compound, such as boron
oxide, boron halide boron acids, and esters of boron acids, in an
amount sufficient to provide from about 0.1 to about 20 atomic
proportions of boron for each mole of acylated nitrogen
composition. Useful dispersants contain from about 0.05 to about
2.0 wt. %, e.g., from about 0.05 to about 0.7 wt. % boron. The
boron, which appears in the product as dehydrated boric acid
polymers (primarily (HBO.sub.2).sub.3), is believed to attach to
the dispersant imides and diimides as amine salts, e.g., the
metaborate salt of the diimide. Boration can be performed by adding
from about 0.5 to 4 wt. %, e.g., from about 1 to about 3 wt %
(based on the mass of acyl nitrogen compound) of a boron compound,
preferably boric acid, usually as a slurry, to the acyl nitrogen
compound and heating with stirring at from about 135.degree. C. to
about 190.degree. C., e.g., 140.degree. C. to 170.degree. C., for
from about one to about five hours, followed by nitrogen stripping.
Alternatively, the boron treatment can be conducted by adding boric
acid to a hot reaction mixture of the dicarboxylic acid material
and amine, while removing water. Other post reaction processes
commonly known in the art can also be applied.
[0057] The dispersant can also be further post treated by reaction
with a so-called "capping agent." Conventionally,
nitrogen-containing dispersants have been "capped" to reduce the
adverse effect such dispersants have on the fluoroelastomer engine
seals. Numerous capping agents and methods are known. Of the known
"capping agents," those that convert basic dispersant amino groups
to non-basic moieties (e.g., amido or imido groups) are most
suitable. The reaction of a nitrogen-containing dispersant and
alkyl acetoacetate (e.g., ethyl acetoacetate (EAA)) is described,
for example, in U.S. Pat. Nos. 4,839,071, 4,839,072, and 4,579,675.
The reaction of a nitrogen-containing dispersant and formic acid is
described, for example, in U.S. Pat. No. 3,185,704. The reaction
product of a nitrogen-containing dispersant and other suitable
capping agents are described in U.S. Pat. No. 4,663,064 (glycolic
acid); U.S. Pat. Nos. 4,612,132, 5,334,321, 5,356,552, 5,716,912,
5,849,676, and 5,861,363 (alkyl and alkylene carbonates, e.g.,
ethylene carbonate); U.S. Pat. No. 5,328,622 (mono-epoxide); U.S.
Pat. No. 5,026,495; U.S. Pat. Nos. 5,085,788, 5,259,906, 5,407,591
(poly (e.g., bis)-epoxides); and U.S. Pat. No. 4,686,054 (maleic
anhydride or succinic anhydride). The foregoing list is not
exhaustive, and other methods of capping nitrogen-containing
dispersants are known to those skilled in the art.
[0058] For adequate piston deposit control, a nitrogen-containing
dispersant can be added in an amount providing the lubricating oil
composition with from about 0.03 wt % to about 0.15 wt %,
preferably from about 0.07 to about 0.12 wt %, of nitrogen.
[0059] Metal-containing or ash-forming detergents function both as
detergents to reduce or remove deposits and as acid neutralizers or
rust inhibitors, thereby reducing wear and corrosion and extending
engine life. Detergents generally comprise a polar head with a long
hydrophobic tail, with the polar head comprising a metal salt of an
acidic organic compound. The salts can contain a substantially
stoichiometric amount of the metal, in which case they are usually
described as normal or neutral salts, and would typically have a
total base number or TBN (as can be measured by ASTM D2896) of from
0 to 80. A large amount of a metal base can be incorporated by
reacting excess metal compound (e.g., an oxide or hydroxide) with
an acidic gas (e.g., carbon dioxide). The resulting overbased
detergent comprises neutralized detergent as the outer layer of a
metal base (e.g. carbonate) micelle. Such overbased detergents can
have a TBN of 150 or greater and typically will have a TBN of from
250 to 450 or more.
[0060] Detergents that can be used include oil-soluble neutral and
overbased sulfonates, phenates, sulfurized phenates,
thiophosphonates, salicylates, naphthenates, and other oil-soluble
carboxylates of a metal, particularly the alkali or alkaline earth
metals, e.g., sodium, potassium, lithium, calcium, and magnesium.
The most commonly used metals are calcium and magnesium, which can
both be present in detergents used in a lubricant, and mixtures of
calcium and/or magnesium with sodium. Particularly convenient metal
detergents are neutral and overbased calcium sulfonates having TBN
of from 20 to 450 TBN, and neutral and overbased calcium phenates
and sulfurized phenates having TBN of from 50 to 450. Combinations
of detergents, whether overbased or neutral or both, can be
used.
[0061] Sulfonates can be prepared from sulfonic acids which are
typically obtained by the sulfonation of alkyl substituted aromatic
hydrocarbons such as those obtained from the fractionation of
petroleum or by the alkylation of aromatic hydrocarbons. Examples
included those obtained by alkylating benzene, toluene, xylene,
naphthalene, diphenyl, or their halogen derivatives such as
chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation
can be performed in the presence of a catalyst with alkylating
agents having from about 3 to more than 70 carbon atoms. The
alkaryl sulfonates usually contain from about 9 to about 80 or more
carbon atoms, preferably from about 16 to about 60 carbon atoms,
per alkyl substituted aromatic moiety.
[0062] The oil soluble sulfonates or alkaryl sulfonic acids can be
neutralized with oxides, hydroxides, alkoxides, carbonates,
carboxylate, sulfides, hydrosulfides, nitrates, borates, and ethers
of the metal. The amount of metal compound is chosen having regard
to the desired TBN of the final product but typically ranges from
about 100 to 220 wt. % (preferably at least 125 wt. %) of that
stoichiometrically required.
[0063] Metal salts of phenols and sulfurized phenols are prepared
by reaction with an appropriate metal compound such as an oxide or
hydroxide, and neutral or overbased products can be obtained by
methods well known in the art. Sulfurized phenols can be prepared
by reacting a phenol with sulfur or a sulfur containing compound
such as hydrogen sulfide, sulfur monohalide, or sulfur dihalide, to
form products which are generally mixtures of compounds in which
two or more phenols are bridged by sulfur containing bridges.
[0064] Dihydrocarbyl dithiophosphate metal salts are frequently
used as antiwear and antioxidant agents. The metal can be an alkali
or alkaline earth metal, or aluminum, lead, tin, molybdenum,
manganese, nickel or copper. The zinc salts are most commonly used
in lubricating oil in amounts of 0.1 to 10 wt %, preferably 0.2 to
2 wt %, based upon the total weight of the lubricating oil
composition. They can be prepared in accordance with known
techniques by first forming a dihydrocarbyl dithiophosphoric acid
(DDPA), usually by reaction of one or more alcohols or a phenol
with P.sub.2S5 and then neutralizing the formed DDPA with a zinc
compound. For example, a dithiophosphoric acid can be made by
reacting mixtures of primary and secondary alcohols. Alternatively,
multiple dithiophosphoric acids can be prepared where the
hydrocarbyl groups on one are entirely secondary in character and
the hydrocarbyl groups on the others are entirely primary in
character. To make the zinc salt, any basic or neutral zinc
compound could be used, but the oxides, hydroxides, and carbonates
are most generally employed. Commercial additives frequently
contain an excess of zinc due to the use of an excess of the basic
zinc compound in the neutralization reaction.
[0065] The preferred zinc dihydrocarbyl dithiophosphates are oil
soluble salts of dihydrocarbyl dithiophosphoric acids and can
comprise zinc dialkyl dithiophosphates. The present invention can
be particularly useful when used with passenger car diesel engine
lubricant compositions containing phosphorus levels of from about
0.02 to about 0.12 wt %, such as from about 0.03 to about 0.10 wt
%, or from about 0.05 to about 0.08 wt %, based on the total mass
of the composition and heavy duty diesel engine lubricant
compositions containing phosphorus levels of from about 0.02 to
about 0.16 wt %, such as from about 0.05 to about 0.14 wt %, or
from about 0.08 to about 0.12 wt %, based on the total mass of the
composition. In one preferred embodiment, lubricating oil
compositions of the present invention contain zinc dialkyl
dithiophosphate derived predominantly (e.g., over 50 mol. %, such
as over 60 mol. %) from secondary alcohols.
[0066] Oxidation inhibitors or antioxidants reduce the tendency of
mineral oils to deteriorate in service. Oxidative deterioration can
be evidenced by sludge in the lubricant, varnish-like deposits on
the metal surfaces, and by viscosity growth. Such oxidation
inhibitors include hindered phenols, alkaline earth metal salts of
alkylphenolthioesters having preferably C.sub.5 to C.sub.12 alkyl
side chains, calcium nonylphenol sulfide, oil soluble phenates and
sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons,
phosphorous esters, metal thiocarbamates, oil soluble copper
compounds as described in U.S. Pat. No. 4,867,890, and
molybdenum-containing compounds.
[0067] Typical oil soluble aromatic amines having at least two
aromatic groups attached directly to one amine nitrogen contain
from 6 to 16 carbon atoms. The amines can contain more than two
aromatic groups. Compounds having a total of at least three
aromatic groups, in which two aromatic groups are linked by a
covalent bond or by an atom or group (e.g., an oxygen or sulfur
atom, or a --CO--, --SO.sub.2-- or alkylene group) and two are
directly attached to one amine nitrogen, are also considered
aromatic amines having at least two aromatic groups attached
directly to the nitrogen. The aromatic rings are typically
substituted by one or more substituents selected from alkyl,
cycloalkyl, alkoxy, aryloxy, acyl, acylamino, hydroxy, and nitro
groups.
[0068] Preferably, lubricating oil compositions useful in the
practice of the present invention, particularly lubricating oil
compositions useful in the practice of the present invention that
are required to contain no greater than 1200 ppm of phosphorus,
contain ashless antioxidants other than benzenediamines, in an
amount of from about 0.1 to about 5 wt. %, preferably from about
0.3 wt. % to about 4 wt. %, more preferably from about 0.5 wt. % to
about 3 wt. %. Where the phosphorus content is required to be
lower, the amount of ashless antioxidant other than benzenediamine
will preferably increase accordingly.
[0069] Representative examples of suitable viscosity modifiers are
polyisobutylene, copolymers of ethylene and propylene,
polymethacrylates, methacrylate copolymers, copolymers of an
unsaturated dicarboxylic acid and a vinyl compound, interpolymers
of styrene and acrylic esters, and partially hydrogenated
copolymers of styrene/isoprene, styrenelbutadiene, and
isoprene/butadiene, as well as the partially hydrogenated
homopolymers of butadiene and isoprene.
[0070] A viscosity index improver dispersant functions both as a
viscosity index improver and as a dispersant. Examples of viscosity
index improver dispersants include reaction products of amines, for
example, polyamines, with a hydrocarbyl-substituted mono- or
dicarboxylic acid in which the hydrocarbyl substituent comprises a
chain of sufficient length to impart viscosity index improving
properties to the compounds. In general, the viscosity index
improver dispersant can be, for example, a polymer of a C.sub.4 to
C.sub.24 unsaturated ester of vinyl alcohol or a C.sub.3 to
C.sub.10 unsaturated mono-carboxylic acid or a C.sub.4 to C.sub.10
di-carboxylic acid with an unsaturated nitrogen-containing monomer
having 4 to 20 carbon atoms; a polymer of a C.sub.2 to C.sub.20
olefin with an unsaturated C.sub.3 to C.sub.10 mono- or
di-carboxylic acid neutralized with an amine, hydroxyamine or an
alcohol; or a polymer of ethylene with a C.sub.3 to C.sub.20 olefin
further reacted either by grafting a C.sub.4 to C.sub.20
unsaturated nitrogen-containing monomer thereon or by grafting an
unsaturated acid onto the polymer backbone and then reacting
carboxylic acid groups of the grafted acid with an amine, hydroxy
amine, or alcohol.
[0071] Friction modifiers and fuel economy agents that are
compatible with the other ingredients of the final oil can also be
included. Examples of such materials include glyceryl monoesters of
higher fatty acids, for example, glyceryl mono-oleate; esters of
long chain polycarboxylic acids with diols, for example, the butane
diol ester of a dimerized unsaturated fatty acid; oxazoline
compounds; and alkoxylated alkyl-substituted mono-amines, diamines
and alkyl ether amines, for example, ethoxylated tallow amine and
ethoxylated tallow ether amine.
[0072] Other known friction modifiers comprise oil-soluble
organo-molybdenum compounds. Such organo-molybdenum friction
modifiers also provide antioxidant and antiwear credits to a
lubricating oil composition. Examples of such oil soluble
organo-molybdenum compounds include dithiocarbamates,
dithiophosphates, dithiophosphinates, xanthates, thioxanthates,
sulfides, and the like, and mixtures thereof. Particularly
preferred are molybdenum dithiocarbamates, dialkyldithiophosphates,
alkyl xanthates, and alkylthioxanthates.
[0073] Additionally, the molybdenum compound can be an acidic
molybdenum compound. These compounds will react with a basic
nitrogen compound as measured by ASTM test D-664 or D-2896
titration procedure and are typically hexavalent. Included are
molybdic acid, ammonium molybdate, sodium molybdate, potassium
molybdate, and other alkaline metal molybdates and other molybdenum
salts, e.g., hydrogen sodium molybdate, MoOC, MoO.sub.2Br.sub.2,
Mo.sub.2O.sub.3Cl.sub.6, molybdenum trioxide or similar acidic
molybdenum compounds.
[0074] Another group of organo-molybdenum compounds useful in the
lubricating compositions of this invention are trinuclear
molybdenum compounds, especially those of the formula
Mo.sub.3S.sub.kL.sub.nQ.sub.z and mixtures thereof wherein the L
are independently selected ligands having organo groups with a
sufficient number of carbon atoms to render the compound soluble or
dispersible in the oil, n is from 1 to 4, k varies from 4 through
7, Q is selected from the group of neutral electron donating
compounds such as water, amines, alcohols, phosphines, and ethers,
and z ranges from 0 to 5 and includes non-stoichiometric values. At
least 21 total carbon atoms should be present among all the ligand
organo groups, such as at least 25, at least 30, or at least 35
carbon atoms.
[0075] Pour point depressants, otherwise known as lube oil flow
improvers (LOFI), lower the minimum temperature at which the fluid
will flow or can be poured. Such additives are well known. Typical
of those additives that improve the low temperature fluidity of the
fluid are C.sub.8 to C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, and polymethacrylates. Foam control can be provided by
an antifoamant of the polysiloxane type, for example, silicone oil
or polydimethyl siloxane.
[0076] Some of the above-mentioned additives can provide a
multiplicity of effects; thus, for example, a single additive can
act as a dispersant-oxidation inhibitor. This approach is well
known and need not be further elaborated herein.
[0077] In the present invention it may be necessary to include an
additive that maintains the stability of the viscosity of the
blend. Thus, although polar group-containing additives achieve a
suitably low viscosity in the pre-blending stage, it has been
observed that some compositions increase in viscosity when stored
for prolonged periods. Additives which are effective in controlling
this viscosity increase include the long chain hydrocarbons
functionalized by reaction with mono- or dicarboxylic acids or
anhydrides which are used in the preparation of the ashless
dispersants as hereinbefore disclosed.
[0078] When lubricating compositions contain one or more of the
above-mentioned additives, each additive is typically blended into
the base stock in an amount that enables the additive to provide
its desired function. Representative effect amounts of such
additives, when used in crankcase lubricants, are listed below in
TABLE 5. All the values listed are exemplary and are stated as
weight percent active ingredient.
TABLE-US-00005 TABLE 5 ADDITIVE Wt % (Desirable) Wt % (Preferred)
Metal Detergents 0.1-15 0.2-9 Corrosion Inhibitor 0.0-5 0.0-1.5
Metal Dihydrocarbyl 0.1-6 0.1-4 Dithiophosphate Antioxidant 0.0-5
0.01-3 Pour Point Depressant 0.01-5 0.01-1.5 Antifoaming Agent
0.0-5 0.001-0.15 Supplemental Antiwear 0.0-1.0 0.0-0.5 Agents
Friction Modifier 0.0-5 0.0-1.5 Viscosity Modifier 0.01-10 0.25-3
Dispersant 0.01-10 0.1-5 Base stock Balance (i.e. Balance (i.e.
~47.5-99.8) ~75.9-99.4)
[0079] Fully formulated passenger car diesel engine lubricating oil
(PCDO) compositions of the present invention preferably have a
sulfur content of less than about 0.4 wt %, such as less than about
0.35 wt %, more preferably less than about 0.03 wt %, such as less
than about 0.15 wt %. Preferably, the Noack volatility of the fully
formulated PCDO (oil of lubricating viscosity plus all additives)
will be no greater than 13, such as no greater than 12, preferably
no greater than 10. Fully formulated PCDOs of the present invention
preferably have no greater than 1200 ppm of phosphorus, such as no
greater than 1000 ppm of phosphorus, or no greater than 800 ppm of
phosphorus. Fully formulated PCDOs of the present invention
preferably have a sulfated ash (SASH) content of about 1.0 wt % or
less.
[0080] Fully formulated heavy duty diesel engine (HDD) lubricating
oil compositions of the present invention preferably have a sulfur
content of less than about 1.0 wt %, such as less than about 0.6 wt
%, more preferably less than about 0.4 wt %, such as less than
about 0.15 wt %. Preferably, the Noack volatility of the fully
formulated HDD lubricating oil composition (oil of lubricating
viscosity plus all additives) will be no greater than 20, such as
no greater than 15, preferably no greater than 12. Fully formulated
HDD lubricating oil compositions of the present invention
preferably have no greater than 1600 ppm of phosphorus, such as no
greater than 1400 ppm of phosphorus, or no greater than 1200 ppm of
phosphorus. Fully formulated HDD lubricating oil compositions of
the present invention preferably have a sulfated ash (SASH) content
of about 1.0 wt % or less.
[0081] Examples of phenol anti-oxidants include
2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butylphenol,
2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol,
2,6-di-tert-butyl-4-n-butylphenol,
2,6-di-tert-butyl-4-iso-butylphenol,
2,6-di-cyclopentyl-4-methylphenol,
2-(.alpha.-methylcyclohexyl)-4,6-dimethylphenol,
2,6-di-octadecyl-4-methylphenol, 2,4,6-tri-cyclohexylphenol,
2,6-di-tert-butyl-4-methoxymethylphenol, o-tert-butylphenol,
2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,
2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,
2,2'-thio-bis(6-tert-butyl-4-methylphenol),
2,2'thio-bis(4-octylphenol),
2,2'-methylene-bis(6-tert-butyl-4-methylphenol),
2,2'-methylene-bis(6-tert-butyl-4-ethylphenol),
2,2'-methylene-bis[4-methyl-6-(.alpha.-methylcyclohexyl)phenol],
2,2'-methylene-bis(4-methyl-6-cyclohexylphenol),
2,2'-methylene-bis(6-nonyl-4-methylphenol),
2,2'-methylene-bis(4,6-di-tert-butylphenol),
2,2'-ethylidene-bis(4,6-di-tert-butylphenol),
2,2'-ethylidene-bis(6-tert-butyl-4-isobutylphenol or
-5-isobutylphenol,
2,2'-methylene-bis[6-(a-methylbenzyl)-4-nonylphenol],
2,2'-methylene-bis[6-(.alpha.,..alpha.-dimethylbenzyl)-4-nonylphenol],
4,4'-methylene-bis(2,6-di-tert-butylphenol),
4,4'-methylene-bis(6-tert-butyl-2-methylphenol),
1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,
2,6-di(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,
1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobuta-
ne, ethylene glycol
bis[3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate],
bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene,
bis[2-(3'-tert-butyl-2'-hydroxy-5
methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate,
1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,
bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide,
bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol
terephthalate,
1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,
1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,
dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, monoethyl
3,5-di-tert-butyl-4-hydroxybenzylphosphonate calcium salt,
4-hydroxylauranilide, 4-hydroxystearanilide,
2,4-bis-octylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-s-triazine,
octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate, esters of
.beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and/or
esters of .beta.-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic
acid with monohydric or polyhydric alcohols, for example with
methanol triethylene glycol octadecanol tris-hydroxyethyl
isocyanurate 1,6-hexanediol bis-hydroxyethyloxalic acid diamide
neopentyl glycol diethylene glycol, amides of
.beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, for
example,
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylen-
ediamine,
N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylene-
diamine, N,N'-bis(3,5-di-tert-butyl-4-
hydroxyphenylpropionyl)hydrazine
[0082] Examples of aminic anti-oxidants include,
N,N'-di-isopropyl-p-phenylenediamine,
N,N'-di-sec-butyl-p-phenylenediamine,
N,N'-bis(1,4-dimethylpentyl)-p-phenylenediamine,
N,N'-bis(1-ethyl-3-methylpentyl)-p-phenylenediamine,
N,N'-bis(1-methylheptyl)-p-phenylenediamine,
N,N'-dicyclohexyl-p-phenylenediamine,
N,N'-di(2-naphthyl)-p-phenylenediamine,
4-(p-toluenesulfonamido)diphenylamine,
N,N'-dimethyl-N,N'-di-sec-butyl-p-phenylenediamine,
4-n-butylaminophenol, 4-butyrylaminophenol, 4-nonanoylaminophenol,
4-dodecanoylaminophenol, 4-octadecanoylaminophenol,
2,6-di-tert-butyl-4-dimethylaminomethylphenol,
2,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane,
N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane,
1,2-di[(2-methylphenyl)amino]ethane, 1,2-di(phenylamino)propane
(o-tolyl)biguanide, di[4-(1',3'-dimethylbutyl)phenyl]amine,
2,3-dihydro-3,3-dimethyl-4H-1,4-benzothiazine, phenothiazine,
N-allylphenothiazine
[0083] Examples of further anti-oxidants include esters of
thiodipropionic acid or of thiodiacetic acid and salts of
dithiocarbamide acid or dithiophosphoric acid
[0084] Examples of metal deactivators include triazoles,
benzotriazoles and their derivatives, tolutriazoles and their
derivatives, 2-mercaptobenzothiazole, 2-mercaptobenzotriazole,
2,5-dimercaptobenzotriazole, 2,5-dimercaptobenzothiadiazole,
5,5'-methylenebisbenzotriazole, 4,5,6,7-tetrahydrobenzotriazole,
salicylidenepropylenediamine, salicylaminoguanidine and their
salts
[0085] Examples of rust inhibitors include a) organic acids and
esters, metal salts and anhydrides thereof, for example:
N-oleoylsarcosine, sorbitol monooleate, lead naphthenate,
alkenylsuccinic anhydride, for example dodecenylsuccinic anhydride,
alkenylsuccinic acid hemiester and hemi-amides, and
4-nonylphenoxyacetic acid; b) Nitrogenous compounds, for example,
primary, secondary or tertiary aliphatic or cycloaliphatic amines
and amine salts of organic and inorganic acids, for example
oil-soluble alkylammonium carboxylates; heterocyclic compounds, for
example, substituted imidazolines and oxazolines, c) Phosphorus
compounds, for example, amine salts of partial esters of phosphoric
acid or partial esters of phosphonic acid, zinc
dialkyldithiophosphates, d) Sulfur compounds, for example, barium
dinonylnaphthalenesulfonates, calcium petroleumsulfonates.
[0086] Examples of viscosity index improvers include polyacrylates,
polymethacrylates, vinylpyrrolidone/methacrylate copolymers,
polyvinylpyrrolidones, polybutenes, olefin copolymers,
styrene/acrylate copolymers, polyethers.
[0087] Examples of pour-point depressants include polymethacrylate
and alkylated naphthalene derivatives.
[0088] Examples of dispersants/surfactants include
polybutenylsuccinamides or -imides, polybutenylphosphonic acid
derivatives, basic magnesium, calcium and barium sulfonates, and
phenolates.
[0089] Examples of anti-wear additives include compounds containing
sulfur and/or phosphorus and/or halogen, such as sulfurized
vegetable oils, zinc dialkyldithiophosphates, tritolylphosphate,
chlorinated paraffins, alkyl sulfides, aryl disulfides and aryl
trisulfides, triphenylphosphorothionates, and
diethanolaminomethyltolyltriazole, di(2-ethylhexyl)amino
methyltolyltriazole.
[0090] The lubricating oil compositions of the present invention
improve the oxidative stability of materials that are subject to
oxidative, thermal, and/or light-induced degradation. These organic
materials can be natural or synthetic. These organic materials can
include "functional fluids," lubricating oils, greases, and fuels,
as well as automatic and manual transmission fluids, power steering
fluid, hydraulic fluids, gas turbine oils, compressor lubricants,
automotive and industrial gear lubricants and heat transfer
oils.
[0091] In one embodiment, in food grade lubricants are used as base
stocks. Such base stocks are those that could have incidental food
contact. These are sometimes referred to as "above the line"
lubricants. Such stocks may be used on food-processing equipment as
a protective antirust film, as a release agent on gaskets or seals
of tank closures and as a lubricant for machine parts and equipment
in locations where the lubricated part is potentially exposed to
food. In one embodiment of the invention, the amount used is the
smallest needed to accomplish the desired technical effect on the
equipment. In a preferred embodiment of the invention, the ADPA is
Naugalube.RTM. 640 and the base stock is such a H1 food grade base
stock.
[0092] Preferred commercially produced Hi food grade lubricants
that can be utilized in the present invention include Tri-Flow.RTM.
and Spray-on.RTM.711.RTM. from Krylon Products Group and
NEVASTANE.RTM. lubricants from TOTAL Lubricants USA, Inc.
[0093] In one embodiment of the invention, base stocks of
lubricating viscosity useful in the context of the present
invention are selected from natural lubricating oils, synthetic
lubricating oils, and mixtures thereof. The lubricating oil can
range in viscosity from light distillate mineral oils to heavy
lubricating oils, such as gasoline engine oils, mineral lubricating
oils, and heavy duty diesel oils. Generally, the viscosity of the
oil ranges from about 2 centistokes to about 40 centistokes,
especially from about 4 centistokes to about 20 centistokes, as
measured at 100.degree. C.
[0094] In one embodiment of the invention, the diesel fuel is a
petroleum-based fuel oil, especially a middle distillate fuel oil.
Such distillate fuel oils generally boil within the range of from
110.degree. C. to 500.degree. C., e.g. 150.degree. C. to
400.degree. C. The fuel oil may comprise atmospheric distillate or
vacuum distillate, cracked gas oil, or a blend in any proportion of
straight run and thermally and/or refinery streams such as
catalytically cracked and hydro-cracked distillates.
[0095] Other examples of base stocks include Fischer-Tropsch fuels.
Fischer-Tropsch fuels, also known as FT fuels, include those
described as gas-to-liquid (GTL) fuels, biomass-to-liquid (BTL)
fuels and coal conversion fuels. To make such fuels, syngas
(CO+H.sub.2) is first generated and then converted to normal
paraffins by a Fischer-Tropsch process. The normal paraffins can
then be modified by processes such as catalytic cracking/reforming
or isomerization, hydrocracking and hydroisomerization to yield a
variety of hydrocarbons such as iso-paraffins, cyclo-paraffins and
aromatic compounds. The resulting FT fuel can be used as such or in
combination with other fuel components and fuel types. Also
suitable are diesel fuels derived from plant or animal sources.
These can be used alone or in combination with other types of
fuel.
[0096] Oils and fats derived from plant or animal materials are
increasingly finding application as fuels and, in particular, as
partial or complete replacements for petroleum derived middle
distillate fuels such as diesel. Commonly, such fuels are known as
"biofuels" or "biodiesels." Biofuels may be derived from many
sources. Among the most common are the alkyl, often methyl, esters
of fatty acids extracted from plants, such as rapeseed, sunflower,
and the like. These types of fuel are often referred to as FAME
(fatty acid methyl esters).
[0097] Base stocks may include natural oils including animal oils
and vegetable oils, e.g., lard oil, castor oil, liquid petroleum
oils and hydrorefined, solvent-treated or acid-treated mineral oils
of the paraffinic, naphthenic, and mixed paraffinic-naphthenic
types. Oils of lubricating viscosity derived from coal or shale
also serve as useful base oils. Other examples of oils and fats
derived from animal or vegetable material are rapeseed oil,
coriander oil, soya bean oil, cottonseed oil, sunflower oil, castor
oil, olive oil, peanut oil, maize oil, almond oil, canola oil,
jojoba oil, palm kernel oil, coconut oil, mustard seed oil,
jatropha oil, beef tallow, and fish oils. Further examples include
oils derived from corn, jute, sesame, shea nut, ground nut, and
linseed oil, and may be derived therefrom by methods known in the
art. Rapeseed oil, which is a mixture of fatty acids partially
esterified with glycerol, is available in large quantities and can
be obtained in a simple way by pressing from rapeseed. Recycled
oils such as used kitchen oils are also suitable.
[0098] Useful base stocks are, for example, alkyl esters of fatty
acids, which include commercial mixtures of the ethyl, propyl,
butyl and especially methyl esters of fatty acids with 12 to 22
carbon atoms. For example, lauric acid, myristic acid, palmitic
acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid,
petroselic acid, ricinoleic acid, elaeostearic acid, linoleic acid,
linolenic acid, eicosanoic acid, gadoleic acid, docosanoic acid, or
erucic acid are useful and have an iodine number from 50 to 150,
especially 90 to 125. Mixtures with particularly advantageous
properties are those which contain mainly, i.e., at least 50 wt. %,
methyl esters of fatty acids with 16 to 22 carbon atoms and 1, 2,
or 3 double bonds. The preferred lower alkyl esters of fatty acids
are the methyl esters of oleic acid, linoleic acid, linolenic acid,
and erucic acid.
[0099] Commercial mixtures of the stated kind are obtained for
example by cleavage and esterification of animal and vegetable fats
and oils by their transesterification with lower aliphatic
alcohols. For production of alkyl esters of fatty acids, it is
advantageous to start from fats and oils which contain low levels
of saturated acids, less than 20%, and which have an iodine number
of less than 130. Blends of the following esters or oils are
suitable, e.g., rapeseed, sunflower, coriander, castor, soya bean,
peanut, cotton seed, beef tallow, and the like. Alkyl esters of
fatty acids based on a new variety of rapeseed oil, the fatty acid
component of which comprises more than 80 wt. % unsaturated fatty
acids with 18 carbon atoms, are preferred.
[0100] Particularly preferred base stocks are oils capable of being
utilized as biofuels. Biofuels, i.e., fuels derived from animal or
vegetable material, are believed to be less damaging to the
environment on combustion and are obtained from a renewable source.
It has been reported that on combustion less carbon dioxide is
formed by the equivalent quantity of petroleum distillate fuel,
e.g., diesel fuel, and very little sulfur dioxide is formed.
Certain derivatives of vegetable oil, e.g., those obtained by
saponification and re-esterification with a monohydric alkyl
alcohol, can be used as a substitute for diesel fuel.
[0101] Preferred biofuels are vegetable oil derivatives, of which
particularly preferred biofuels are alkyl ester derivatives of
rapeseed oil, cottonseed oil, soya bean oil, sunflower oil, olive
oil, or palm oil, rapeseed oil methyl ester being especially
preferred, either alone or in admixture with other vegetable oil
derivatives, e.g., mixtures in any proportion of rapeseed oil
methyl ester and palm oil methyl ester.
[0102] At present, biofuels are most commonly used in combination
with petroleum-derived oils. The present invention is applicable to
mixtures of biofuel and petroleum-derived fuels in any ratio. For
example, at least 5%, preferably at least 25%, more preferably at
least 50%, and most preferably at least 95% by weight of the oil,
may be derived from a plant or animal source.
[0103] Synthetic base stock lubricating oils include hydrocarbon
oils and halo-substituted hydrocarbon oils such as polymerized and
interpolymerized olefins (e.g., polybutylenes, polypropylenes,
propylene-isobutylene copolymers, chlorinated polybutylenes,
poly(1-hexenes), poly(1 octenes), poly(1-decenes)); alkylbenzenes
(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenols); and alkylated diphenyl ethers
and alkylated diphenyl sulfides and derivative, analogs, and
homologs thereof. Also useful are synthetic oils derived from a gas
to liquid process from Fischer-Tropsch synthesized hydrocarbons,
which are commonly referred to as gas to liquid or "GTL" base
oils.
[0104] Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
known synthetic lubricating oils. These are exemplified by
polyoxyalkylene polymers prepared by polymerization of ethylene
oxide or propylene oxide and the alkyl and aryl ethers of
polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol
ether having a molecular weight of 1000 or diphenyl ether of
polyethylene glycol having a molecular weight of 1000 to 1500), and
mono- and polycarboxylic esters thereof, for example, the acetic
acid esters, mixed C.sub.3-C.sub.8 fatty acid esters, and C.sub.13
oxo acid diester of tetraethylene glycol.
[0105] Another suitable class of synthetic base stock lubricating
oils comprises the esters of dicarboxylic acids (e.g., phthalic
acid, succinic acid, alkyl succinic acids and alkenyl succinic
acids, maleic acid, azelaic acid, suberic acid, sebasic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid,
alkylmalonic acids, alkenyl malonic acids) with a variety of
alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether,
propylene glycol). Specific examples of such esters includes
dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate,
dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl
phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl
diester of linoleic acid dimer, and the complex ester formed by
reacting one mole of sebacic acid with two moles of tetraethylene
glycol and two moles of 2 ethylhexanoic acid.
[0106] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
Silicon-based oils (such as the polyalkyl-, polyaryl-, polyalkoxy-,
or polyaryloxy-siloxane oils and silicate oils) comprise another
useful class of synthetic lubricating oils. Other synthetic
lubricating oils include liquid esters of phosphorus-containing
acids, polymeric tetrahydrofurans, poly-.alpha.-olefins, and the
like.
[0107] Silicon-based oils such as the polyalkyl-, polyaryl-,
polyalkoxy- or polyaryloxysilicone oils and silicate oils comprise
another useful class of synthetic base stock lubricants; such oils
include tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-ethylhexyl)silicate,
tetra-(4-methyl-2-ethylhexyl)silicate,
tetra-(p-tert-butyl-phenyl)silicate,
hexa-(4-methyl-2-ethylhexyl)disiloxane, poly(methyl)siloxanes and
poly(methylphenyl)siloxanes. Other synthetic lubricating oils
include liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, diethyl ester of
decylphosphonic acid) and polymeric tetrahydrofurans.
[0108] The lubricating oil may be derived from unrefined, refined,
rerefined oils, or mixtures thereof. Unrefined oils are 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 include 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. 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 include 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. Rerefined oils are obtained by treating refined
oils in processes similar to those used to obtain the refined oils.
These rerefined 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.
[0109] Lubricating oil base stocks derived from the
hydroisomerization of wax may also be used, either alone or in
combination with the aforesaid natural and/or synthetic base
stocks. Such wax isomerate oil is produced by the
hydroisomerization of natural or synthetic waxes or mixtures
thereof over a hydroisomerization catalyst. Natural waxes are
typically the slack waxes recovered by the solvent dewaxing of
mineral oils; synthetic waxes are typically the wax produced by the
Fischer-Tropsch process. The resulting isomerate product is
typically subjected to solvent dewaxing and fractionation to
recover various fractions having a specific viscosity range. Wax
isomerate is also characterized by possessing very high viscosity
indices, generally having a viscosity index of at least 130,
preferably at least 135 or higher and, following dewaxing, a pour
point of about -20.degree. C. or lower.
[0110] The base stock of lubricating viscosity can comprise a Group
I, Group II, or Group III base stock or base oil blends of the
aforementioned base stocks. Preferably, the oil of lubricating
viscosity is a Group II or Group III base stock, or a mixture
thereof, or a mixture of a Group I base stock and one or more of a
Group II and Group III. Preferably, a major amount of the oil of
lubricating viscosity is a Group II, Group III, Group IV, or Group
V base stock, or a mixture thereof. The base stock, or base stock
blend, preferably has a saturate content of at least 65%, e.g., at
least 75% or at least 85%. Most preferably, the base stock, or base
stock blend, has a saturate content of greater than 90%.
[0111] Preferably the volatility of the oil or oil blend, as
measured by the Noack volatility test (ASTM D5880), is less than or
equal to 30%, preferably less than or equal to 25%, more preferably
less than or equal to 20%, most preferably less than or equal to
16%. Preferably, the viscosity index (VI) of the oil or oil blend
is at least 85, preferably at least 100, most preferably from about
105 to 140.
[0112] Definitions for the base stocks and base oils in this
invention are the same as those found in the American Petroleum
Institute (API) publication "Engine Oil Licensing and Certification
System," Industry Services Department (14th ed., December 1996),
Addendum 1, Dec. 1998. This publication categorizes base stocks as
follows.
[0113] (a) Group I base stocks contain less than 90 percent
saturates (as determined by ASTM D 2007) and/or greater than 0.03
percent sulfur (as determined by ASTM D 2622, ASTM D 4294, ASTM D
4927 and ASTM D 3120) and have a viscosity index greater than or
equal to 80 and less than 120 (as determined by ASTM D 2270).
[0114] (b) Group II base stocks contain greater than or equal to 90
percent saturates (as determined by ASTM D 2007) and less than or
equal to 0.03 percent sulfur (as determined by ASTM D 2622, ASTM D
4294, ASTM D 4927 and ASTM D 3120) and have a viscosity index
greater than or equal to 80 and less than 120 (as determined by
ASTM D 2270).
[0115] (c) Group III base stocks contain greater than or equal to
90 percent saturates (as determined by ASTM D 2007) and less than
or equal to 0.03 percent sulfur (as determined by ASTM D 2622, ASTM
D 4294, ASTM D 4927 and ASTM D 3120) and have a viscosity index
greater than or equal to 120 (as determined by ASTM D 2270).
[0116] (d) Group IV base stocks are polyalphaolefins (PAO).
[0117] (e) Group V base stocks include all other base stocks not
included in Groups I, II, III, or IV.
[0118] In one embodiment of the invention, the additive package is
added to the base stock in the form of an additive package
concentrate. The total amount of additive components in the
concentrates generally varies from 20 to 95 wt. % or more, with the
balance being diluent oil. The diluent oil may be the base stocks
of the invention, as defined above, or a hydrocarbon, preferably
aromatic, solvent or mixtures thereof. The concentrates may contain
other additives, as listed below. Typically, the additive package
concentrates are added to the base stock in an amount sufficient to
provide the proper weight % of ADPA, PNA and/or sulfur-containing
phenol to the finished lubricating oil composition.
[0119] Embodiments of the invention will become more evident in
view of the following non-limiting examples.
Mid-High Temperature Thermo-Oxidation Engine Oil Simulation Test
(TEOST MHT)
[0120] ASTM D7097 is the "Standard Test Method for Determination of
Moderately High Temperature Piston Deposits by Thermo-oxidation
Engine Oil Simulation Tests," approved December 2004, which is
incorporated by reference in its entirety for any purpose. ASTM
D7097 is a new standard lubricant industry test for the evaluation
of the oxidation and carbonaceous deposit-forming characteristics
of engine oils. The test is designed to simulate high temperature
deposit formation in the piston ring belt area of modern
engines.
[0121] The test is also a useful tool for studying the formation of
volatile organic molecules upon oxidation of an engine oil. It is
generally understood that the formation of volatile organic
molecules upon oxidation of a lubricant are detrimental because
they lead to an increase in emissions, and can also promote further
polymerization of the lubricant. Polymerization of the lubricant
leads to viscosity increase, which is also undesirable. The
additive combination of this invention is effective at controlling
both deposit formation and the formation of volatile organic
molecules. Typically, polar volatile organic molecules are formed
by decomposition of an organic peroxide in the lubricant. This
decomposition produces an organic alkoxy radical that can react
with another oil molecule to produce an alcohol, or that can
degrade to form aldehydes and ketones. The degradation to aldehydes
and ketones generally reduces molecular weight and thus produces
more volatile fragments, which are pollutants and are also active
precursors to oligomers and polymers that thicken the lubricant. It
is therefore highly desirable to prevent or eliminate the formation
of these polar volatile organic molecules.
[0122] The TEOST MHT determines the mass of deposit formed on a
specially constructed, pre-weighed steel depositor rod. The fully
formulated lubricant (8.4 g) and an organometallic catalyst (about
0.1 g) are added to a flask equipped with a Teflon stirring bar and
stirred for 20-60 minutes without heating. The depositor rod,
sample flask, oil inlet, air inlet, and volatiles collection vial
are fitted to the TEOST apparatus according to manufacturers
specifications. The pump is started at a high flow rate and run
until the test oil reaches the connection of the pump and oil feed
tube, at which point the pump flow is turned to zero. The heater
switch is turned on and when the depositor rod temperature
controller is between 200-210.degree. C., the pump speed increased
to achieve a sample delivery of 0.25.+-.0.02 g/min, making sure
that the oil is flowing down the depositor rod and is not leaking.
The temperature is allowed to stabilize at 285.+-.2.degree. C. and
the test is run under these conditions for 24 hrs.
[0123] Three test tubes are prepared with cyclohexane or another
suitable hydrocarbon solvent for extraction of oil from the
depositor rod. The test instrument is disassembled as per
manufacturer's instructions and the depositor rod is transferred to
a weighing boat and kept under cover. The depositor rod is placed
successively for 10 minutes each in each of the three test tubes
prepared with a hydrocarbon solvent. The rod is placed in tared
weighing boat and allowed to sit for 10 minutes to insure
evaporation of the hydrocarbon solvent. The rod and the boat are
weighed, verifying that a constant mass has been achieved. The
contents of the three test tubes, along with the lower-end cap
deposits and glass mantle deposits, are washed into a common
container which is then filtered using a glass funnel equipped with
a filter cartridge. After completing the filtering, the filter
cartridge is dried under vacuum and weighed, until a constant mass
is achieved. The total mass of the deposits from the depositor rod
and filter deposits is then determined.
[0124] During the 24 hour duration of the test, the volatile
compounds in the formulated oil that are there originally or those
formed during the test, are flashed off the depositor rod. These
volatiles condense on the glass mantle and are collected on a
continuous basis in a small, weighed vial. The vial and volatiles
are measured at the end of the 24 hour test period and the amount
of volatiles is calculated by subtracting the original weight of
the vial.
Pressurized Differential Scanning Calorimeter (PDSC) Testing
[0125] PDSC testing can be used to measure of the oxidation
induction time (OIT) of materials. The samples discussed in this
application were tested in accordance with the parameters listed in
TABLE 1 (displayed above). Further, the PDSC instrument used was a
Mettler DSC27HP manufactured by Mettler-Toledo, Inc. The PDSC
method employs a steel cell under constant oxygen pressure
throughout each run. The instrument has a typical repeatability of
+5.0 minutes with 95 percent confidence for an OIT of 200 minutes.
At the beginning of a PDSC run, the PDSC steel cell is pressurized
with oxygen and heated at a rate of 40.degree. C. per minute to the
isothermal temperature listed in TABLE 1. The induction time is
measured from the time the sample reaches its isothermal
temperature until the enthalpy change is observed. The longer the
oxidation induction time, the better the oxidation stability of the
oil, i.e., longer OITs indicate more stable compositions. For every
50 grams of test oil prepared, 40 .mu.L of oil soluble ferric
naphthenate (6 weight percent in mineral oil) was added, prior to
PDSC testing, to facilitate 50 ppm of iron in oil.
[0126] The antioxidant effect of the present invention may
preferably be demonstrated in, for example, a low
phosphorus-containing SAE 5W20 fully formulated engine oil. Such an
engine oil was used in the PDSC testing discussed herein. The SAE
5W20 engine oil formulation was pre-blended with the components
shown in TABLE 6, all of which are commercially available. The
antioxidant package was subsequently added to the engine oil
pre-blend. The PDSC testing was carried out at 185.degree. C.
TABLE-US-00006 TABLE 6 SAE 20 Engine oil Pre-blend Formula Amounts
in Composition composition, wt % Overbased Calcium Sulfonate
Detergents 2.5 ZDDP 0.5 Succinimide Dispersant 6.4 Pour Point
Depressant 0.1 OCP VI Improver 5.0 Base oil, API Group II
Balance
EXAMPLES
[0127] Additive package blends 1-6 and A-C were prepared according
to the proportions shown in TABLE 7.
TABLE-US-00007 TABLE 7 Sulfur- Expected ADPA- PNA- containing
Expected TEOST TEOST Naugalube Naugard phenol- OIT, OIT, MHT, MHT,
438L PNA Naugalube-15 minutes minutes mg mg Examples 1-6 1 0.7 0.15
0.15 39 34.3 37.4 57.6 2 0.8 0.1 0.1 39.8 35.2 44.9 56.7 3 0.75 0.2
0.05 45.5 38.3 43.0 57.2 4 0.7 0.1 0.2 34.9 31.9 39.1 57.5 5 0.9
0.05 0.05 39.6 36.1 43.3 56.9 6 0.75 0.05 0.2 40.3 31.1 47.3 57.1
Comparative Examples A-C A 1.0 0 0 37 -- 55 -- B 0 1 0 52.0 -- 63.7
-- C 0 0 1 3.8 -- 63.0 --
[0128] Each of additive packages 1-6 and A-C was blended with base
stock at a weight ratio of about 99:1, base stock to additive
package, to produce lubricant oil compositions. Example blends 1-6
are representative embodiments of the invention. Example blends A-C
are comparative. The lubricant oil compositions were tested for OIT
and TEOST MHT. The results are shown in TABLE 7.
[0129] As shown above, Comparative Examples A, B, and C represent
pure ADPA, PNA and sulfur-containing phenol, respectively. These
blends demonstrated OIT values of 37.0, 52.0, and 3.8 minutes,
respectively, and TEOST MHT values of 55.0, 63.7 and 63 grams of
deposits, respectively. The expected OlTs for additive packages may
be calculated by adding the OlTs of pure ADPA, PNA and
sulfur-containing phenol according to the appropriate weight
percentages of the respective mixture. The expected TEOST MHT
values for additive packages may be calculated in a similar manner.
The expected OlTs and the expected TEOST MHT values are also shown
in TABLE 7.
[0130] Surprisingly and unexpectedly, the lubricating oil blend 1,
which is representative of the present invention, demonstrates
TEOST MHT values below 40. In addition, the additive packages of
the embodiments of the invention demonstrate OIT values that are
greater than 38 minutes, when tested according to the parameters
mentioned above.
[0131] In addition, the additive packages of the embodiments of the
invention surprisingly and unexpectedly demonstrate superior OlTs
when compared to the expected values--in most cases, greater than
13% increases. Further, these additive packages show superior TEOST
MHT values when compared to the expected values--in most cases,
greater than 20% decreases, which are also surprising and
unexpected.
[0132] Any feature described or claimed with respect to any
disclosed implementation may be combined in any combination with
any one or more other feature(s) described or claimed with respect
to any other disclosed implementation or implementations, to the
extent that the features are not necessarily technically
incompatible, and all such combinations are within the scope of the
present invention. Furthermore, the claims appended below set forth
some non-limiting combinations of features within the scope of the
invention, but also contemplated as being within the scope of the
invention are all possible combinations of the subject matter of
any two or more of the claims, in any possible combination,
provided that the combination is not necessarily technically
incompatible.
* * * * *