U.S. patent application number 14/477098 was filed with the patent office on 2015-04-09 for compositions with improved varnish control properties.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. The applicant listed for this patent is Michael L. Blumenfeld, Angela S. Galiano-Roth, David G.L. Holt, William Hum. Invention is credited to Michael L. Blumenfeld, Angela S. Galiano-Roth, David G.L. Holt, William Hum.
Application Number | 20150099675 14/477098 |
Document ID | / |
Family ID | 51626169 |
Filed Date | 2015-04-09 |
United States Patent
Application |
20150099675 |
Kind Code |
A1 |
Hum; William ; et
al. |
April 9, 2015 |
COMPOSITIONS WITH IMPROVED VARNISH CONTROL PROPERTIES
Abstract
A method for improving varnish control in a mechanical device
requiring hydraulic fluids, turbine oils, industrial fluids,
circulating oils, or combinations thereof. The method involves
supplying the mechanical device with a lubricating composition
including a Group III lubricating oil base stock. The Group III
lubricating oil base stock has a viscosity from 3.8 to 8.5
mm.sup.2/s at 100.degree. C., a viscosity index greater than 120, a
sulfur content less than 0.0003 weight percent, and an aromatic
hydrocarbon content less than 0.2 weight percent, based on the
total weight of the Group III lubricating oil base stock. Varnish
reduction properties are improved as compared to varnish reduction
properties achieved using a lubricating composition containing a
different Group III lubricating oil base stock. The disclosure also
provides lubricating compositions used in the method.
Inventors: |
Hum; William; (Philadelphia,
PA) ; Holt; David G.L.; (Medford, NJ) ;
Blumenfeld; Michael L.; (Haddonfield, NJ) ;
Galiano-Roth; Angela S.; (Mullica Hill, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hum; William
Holt; David G.L.
Blumenfeld; Michael L.
Galiano-Roth; Angela S. |
Philadelphia
Medford
Haddonfield
Mullica Hill |
PA
NJ
NJ
NJ |
US
US
US
US |
|
|
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
51626169 |
Appl. No.: |
14/477098 |
Filed: |
September 4, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61886312 |
Oct 3, 2013 |
|
|
|
Current U.S.
Class: |
508/110 ; 208/18;
208/19 |
Current CPC
Class: |
C10N 2040/08 20130101;
C10N 2030/04 20130101; C10M 101/02 20130101; C10M 2205/173
20130101; C10M 111/04 20130101; C10M 107/02 20130101; C10N 2040/12
20130101; C10M 2203/1025 20130101; C10M 2205/0206 20130101; C10M
2203/1025 20130101; C10N 2020/00 20130101; C10N 2020/02 20130101;
C10M 2203/1025 20130101; C10N 2020/00 20130101; C10N 2020/02
20130101; C10N 2020/065 20200501; C10M 2205/0206 20130101; C10N
2020/02 20130101; C10N 2020/071 20200501; C10M 2203/1025 20130101;
C10N 2020/02 20130101; C10N 2020/00 20130101; C10M 2203/1025
20130101; C10N 2020/00 20130101; C10N 2020/02 20130101; C10N
2020/065 20200501; C10M 2205/0206 20130101; C10N 2020/02 20130101;
C10N 2020/071 20200501 |
Class at
Publication: |
508/110 ; 208/18;
208/19 |
International
Class: |
C10M 107/02 20060101
C10M107/02; C10M 101/02 20060101 C10M101/02 |
Claims
1. A method for improving varnish control in a mechanical device
requiring hydraulic fluids, turbine oils, industrial fluids,
circulating oils, or combinations thereof, said method comprising:
supplying the mechanical device with a lubricating composition
comprising a Group III lubricating oil base stock; wherein the
Group III lubricating oil base stock has a viscosity from 3.8 to
8.5 mm.sup.2/s at 100.degree. C., a viscosity index greater than
120, a sulfur content less than 0.0003 weight percent, and an
aromatic hydrocarbon content less than 0.2 weight percent, based on
the total weight of the Group III lubricating oil base stock; and
wherein varnish reduction properties are improved as compared to
varnish reduction properties achieved using a lubricating
composition containing a different Group III lubricating oil base
stock.
2. The method of claim 1 wherein the Group III lubricating oil base
stock has a viscosity from 4.0 to 8.3 mm.sup.2/s at 100.degree. C.,
a viscosity index greater than 125, a sulfur content less than
0.0002 weight percent, and an aromatic hydrocarbon content less
than 0.18 weight percent, based on the total weight of the Group
III lubricating oil base stock.
3. The method of claim 1 wherein the Group III lubricating oil base
stock contains consecutive carbon numbers, and is a Gas-to-Liquids
(GTL) oil base stock or a Fischer-Tropsch wax derived oil base
stock.
4. The method of claim 1 wherein the Group III lubricating oil base
stock is produced from natural gas and subsequent wax
isomerization.
5. The method of claim 1 wherein the lubricating composition
further comprises (i) a Group II co-base stock; wherein the Group
II co-base stock has a viscosity from 6.5 to 11.0 mm.sup.2/s at
40.degree. C., is isoparaffinic, and is produced from natural gas
and subsequent wax isomerization; or (ii) a heavy Group II base
stock having a viscosity from 10.0 to 13.0 mm.sup.2/s at
100.degree. C., a viscosity index greater than 90, a sulfur content
less than 0.001 weight percent, and saturates content greater than
99%.
6. The method of claim 1 wherein the Group III lubricating oil base
stock is present in an amount from 80 weight percent to 99 weight
percent, based on the total weight of the lubricating
composition.
7. The method of claim 1 wherein the lubricating composition
further comprises at least one of a viscosity index improver, an
antiwear agent, an antifoam, a metal deactivator, a solubility
improver, and a demulsifier.
8. The method of claim 1 wherein the lubricating composition
further comprises at least one of a dispersant, an antioxidant, a
corrosion inhibitor, and a co-base stock.
9. The method of claim 1 wherein the improved varnish reduction
properties are rated according to a Coordinating Research Council
(CRC) rating scale, the sulfur content is determined according to
ASTM D2622, and the aromatic hydrocarbon content is determined
according to ASTM D7419.
10. The method of claim 1 wherein the mechanical device is a
hydraulic system or a turbine system.
11. A lubricating composition comprising: a Group III lubricating
oil base stock, wherein the Group III lubricating oil base stock
has a viscosity from 3.8 to 8.5 mm.sup.2/s at 100.degree. C., a
viscosity index greater than 120, a sulfur content less than 0.0003
weight percent, and an aromatic hydrocarbon content less than 0.2
weight percent, based on the total weight of the Group III
lubricating oil base stock; and optionally one or more of an
antiwear additive, viscosity index improver, antioxidant,
dispersant, pour point depressant, corrosion inhibitor, metal
deactivator, seal compatibility additive, antifoam agent, co-base
stock, pour point depressant, seal compatibility additive,
solubility improver, and antirust additive; wherein, in a
mechanical device supplied with the lubricating composition,
varnish reduction properties are improved as compared to varnish
reduction properties achieved using a lubricating composition
containing a different Group III lubricating oil base stock.
12. The lubricating composition of claim 11 which is a hydraulic
fluid, turbine oil, industrial fluid, circulating oil, or
combination thereof.
13. The lubricating composition of claim 11 wherein the Group III
lubricating oil base stock has a viscosity from 4.0 to 8.3
mm.sup.2/s at 100.degree. C., a viscosity index greater than 125, a
sulfur content less than 0.0002 weight percent, and an aromatic
hydrocarbon content less than 0.18 weight percent, based on the
total weight of the Group III lubricating oil base stock.
14. The lubricating composition of claim 11 wherein the Group III
lubricating oil base stock contains consecutive carbon numbers, and
is a Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch wax
derived oil base stock.
15. The lubricating composition of claim 11 wherein the Group III
lubricating oil base stock is produced from natural gas and
subsequent wax isomerization.
16. The lubricating composition of claim 11 further comprising (i)
a Group II co-base stock; wherein the Group II co-base stock has a
viscosity from 6.5 to 11.0 mm.sup.2/S at 40.degree. C., is
isoparaffinic, and is produced from natural gas and subsequent wax
isomerization; or (ii) a heavy Group II base stock having a
viscosity from 10.0 to 13.0 mm.sup.2/s at 100.degree. C., a
viscosity index greater than 90, a sulfur content less than 0.001
weight percent, and saturates content greater than 99%.
17. The lubricating composition of claim 11 wherein Group III
lubricating oil base stock is present in an amount from 80 weight
percent to 99 weight percent, based on the total weight of the
lubricating composition.
18. The lubricating composition of claim 11 wherein the improved
varnish reduction properties are rated according to a Coordinating
Research Council (CRC) rating scale, the sulfur content is
determined according to ASTM D2622, and the aromatic hydrocarbon
content is determined according to ASTM D7419.
19. The lubricating composition of claim 11 further comprising a
dispersant, an antioxidant, a corrosion inhibitor, an antiwear
agent, an antifoam, a metal deactivator, a solubility improver, or
combinations thereof.
20. The lubricating composition of claim 11 wherein the mechanical
device is a hydraulic system or a turbine system.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional
Application Ser. No. 61/886,312 filed Oct. 3, 2013, which is herein
incorporated by reference in its entirety.
FIELD
[0002] This disclosure relates to a method for improving varnish
control in a mechanical device requiring hydraulic fluids, turbine
oils, industrial fluids, circulating oils, or combinations thereof.
This disclosure also provides lubricating compositions used in the
method.
BACKGROUND
[0003] The art of formulating lubricating oil compositions has
become more complex as a result of increased government and user
environmental standards and increased user performance
requirements. Lubricants are typically marketed based upon features
such as fluid durability, deposit control, antiwear protection,
filterability, water tolerance, rust/corrosion protection, and
viscosity.
[0004] Deposit or varnish is a growing problem in many hydraulic
and sensitive lubrication applications. Varnish formation is
usually the result of a complex series of events which come from
lubricant degradation. There are three common causes of oil
degradation. One cause is oxidation at elevated temperatures
leading to the formation of decomposition products, including acids
and insoluble particulate, referred to as deposits, varnish, and
sludge. The second cause is thermal degradation, such as, pressure
induced dieseling or micro-dieseling which occurs when entrained
air bubbles are collapsed under high pressure. The third cause,
especially for hydraulic fluids, is external contamination of the
fluid.
[0005] It is well known that API Group II and III base stock oils
and GTL are typically better than API Group I base oils. The Group
II and III base stocks are better because of the oxidation
stability of hydroprocessed or hydrocracked base stocks as well as
enhanced viscosity and temperature properties compared to
conventional solvent refined base stocks. Consequently, many
lubricants are being formulated with API Group II and III base
stock. A known deficiency of these non-polar, highly saturated API
Group II and III base stocks are their lower ability to solubilize
or suspend lubricant degradation byproducts in solution once
formed. For this reason, API Group II/III based lubricants are more
susceptible to deposit formation once oil degradation has
begun.
[0006] A large number of failures in hydraulic and other
applications have been associated with varnish and sludge
formation. Sludge and varnish are insoluble materials formed as a
result of either degradation reactions in the oil, contamination of
oil or both. Explanations typically include the nature of the base
oil, additive instability or degradation, bulk oil oxidation,
electrostatic discharge, and low electrical conductivity, among
others.
[0007] There is a need to develop hydraulic formulations that use
API Group III or other base stocks and that minimize or prevent
deposit formation in the device being lubricated.
[0008] The present disclosure provides many advantages, which shall
become apparent as described below.
SUMMARY
[0009] This disclosure relates in part to a method for improving
varnish control in a mechanical device requiring hydraulic fluids,
turbine oils, industrial fluids, circulating oils, or combinations
thereof. The method comprises supplying the mechanical device with
a lubricating composition comprising a Group III lubricating oil
base stock. The Group III lubricating oil base stock, e.g., a
Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch wax
derived oil base stock, has a viscosity from 3.8 to 8.5 mm.sup.2/s
at 100.degree. C., a viscosity index greater than 120, preferably
greater than 125, and more preferably greater than 130, a sulfur
content less than 0.0003 weight percent, and an aromatic
hydrocarbon content less than 0.2 weight percent, based on the
total weight of the Group III lubricating oil base stock. Varnish
reduction properties are improved as compared to varnish reduction
properties achieved using a lubricating composition containing a
different Group III lubricating oil base stock.
[0010] This disclosure also relates in part to a lubricating
composition that comprises a Group III lubricating oil base stock,
and optionally one or more of an antiwear additive, viscosity index
improver, antioxidant, dispersant, pour point depressant, corrosion
inhibitor, metal deactivator, seal compatibility additive, antifoam
agent, co-base stock, pour point depressant, seal compatibility
additive, solubility improver, and anti-rust additive. The Group
III lubricating oil base stock, e.g., a Gas-to-Liquids (GTL) oil
base stock or a Fischer-Tropsch wax derived oil base stock, has a
viscosity from 3.8 to 8.5 mm.sup.2/s at 100.degree. C., a viscosity
index greater than 120, preferably greater than 125, and more
preferably greater than 130, a sulfur content less than 0.0003
weight percent, and an aromatic hydrocarbon content less than 0.2
weight percent, based on the total weight of the Group III
lubricating oil base stock. In a mechanical device supplied with
the lubricating composition, varnish reduction properties are
improved as compared to varnish reduction properties achieved using
a lubricating composition containing a different Group III
lubricating oil base stock.
[0011] It has been surprisingly found that with lubricating
compositions containing a Group III lubricating oil base stock in
accordance with this disclosure, varnish reduction properties are
improved as compared to varnish reduction properties achieved using
a lubricating composition containing a different Group III
lubricating oil base stock.
[0012] Further objects, features and advantages of the present
disclosure will be understood by reference to the following
drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows photographs taken to determine the extent of
varnish deposit in a hydraulic fluid pump test according to the
Coordinating Research Council (CRC) rating scale.
[0014] FIG. 2 shows photographs taken to determine the extent of
varnish deposit in a turbine oil pump test according to the
Coordinating Research Council (CRC) rating scale.
DETAILED DESCRIPTION
[0015] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0016] In accordance with this disclosure, varnish reduction
properties are improved with lubricating compositions containing a
Group III lubricating oil base stock in accordance with this
disclosure, as compared to varnish reduction properties achieved
using a lubricating composition containing a different Group III
lubricating oil base stock.
Lubricating Oil Group III Base Stocks
[0017] The lubricating oil Group III base stocks, e.g., a
Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch wax
derived oil base stock, useful in this disclosure have a viscosity
from 3.8 to 8.5 mm.sup.2/s at 100.degree. C., a viscosity index
greater than 120, preferably greater than 125, and more preferably
greater than 130, a sulfur content less than 0.0003 weight percent
(determined according to ASTM D2622), and an aromatic hydrocarbon
content less than 0.2 weight percent (determined according to ASTM
D7419), based on the total weight of the Group III lubricating oil
base stock.
[0018] Preferably, the Group III lubricating oil base stocks, e.g.,
a Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch wax
derived oil base stock, have a viscosity from 4.0 to 8.3 mm.sup.2/s
at 100.degree. C., a viscosity index greater than 125, preferably
greater than 130, a sulfur content less than 0.0002 weight percent,
and an aromatic hydrocarbon content less than 0.18 weight percent,
based on the total weight of the Group III lubricating oil base
stock.
[0019] More preferably, the Group III lubricating oil base stocks,
e.g., a Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch
wax derived oil base stock, have a viscosity from 4.0 to 8.3
mm.sup.2/s at 100.degree. C., a viscosity index greater than 130, a
sulfur content less than 0.0002 weight percent, and an aromatic
hydrocarbon content less than 0.18 weight percent, based on the
total weight of the Group III lubricating oil base stock.
[0020] The Group III lubricating oil base stock preferably contains
consecutive carbon numbers, and is highly isoparaffinic in nature.
The Group III lubricating oil base stock is preferably produced
from natural gas and subsequent wax isomerization.
[0021] Illustrative Group III lubricating oil base stocks useful in
this disclosure include, for example, Shell QHVI 4, Shell QHVI 8,
and the like.
[0022] The lubricating compositions of this disclosure may also
have a so-called multigrade rating such as SAE 75W-80, 75W-90,
75W-140, 80W-90, 80W-140, 85W-90, or 85W-140. Multigrade lubricants
may include a viscosity improver which is formulated with the base
oil of lubricating viscosity to provide the above lubricant grades.
Useful viscosity improvers include but are not limited to
polyolefins, such as ethylene-propylene copolymers, or polybutylene
rubbers, including hydrogenated rubbers, such as styrene-butadiene
or styrene-isoprene rubbers; or polyacrylates, including
polymethacrylates. In one embodiment, the viscosity improver is a
polyolefin or polymethacrylate. These additives, as well as
additional additives which may be used in the compositions of the
disclosure, are described in more detail herein.
[0023] In one embodiment, the lubricating composition of this
disclosure further comprises a Group II co-base stock. The Group II
co-base stock preferably has a viscosity from 6.5 to 11.0
mm.sup.2/s at 40.degree. C., is isoparaffinic, and is produced from
natural gas and subsequent wax isomerization. Illustrative Group II
co-base stocks include, for example, Shell QHVI 3, and the
like.
[0024] In another embodiment, the lubricating composition of this
disclosure further comprises a heavy Group II co-base stock. The
heavy Group II co-base stock preferably has a viscosity from 10.0
to 13.0 mm.sup.2/s at 100.degree. C., a viscosity index greater
than 90, a sulfur content less than 0.001 weight percent, and
saturates content greater than 99%. Illustrative Group II co-base
stocks include, for example, EHC 110 and Flint Hills 600-HC.
[0025] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the lubricating
composition of the present disclosure is in the form of a
concentrate (which may be combined with additional oil to form, in
whole or in part, a finished lubricant), the ratio of the additives
to the base oil of lubricating viscosity and/or to diluent oil
include the ranges of 1:99 to 99:1 by weight, or from 80:20 to
10:90 by weight.
[0026] The base oil constitutes the major component of the
lubricant composition of the present disclosure and typically is
present in an amount ranging from 50 to 99 weight percent,
preferably from 80 to 99 weight percent, more preferably from 70 to
95 weight percent, and even more preferably from 85 to 95 weight
percent, based on the total weight of the composition. Mixtures of
synthetic and natural base oils may be used if desired. Bi-modal
mixtures of Group I, II, III, IV, and/or V base stocks may be used
if desired.
Lubricating Oil Co-Base Stocks
[0027] A wide range of lubricating co-base oils useful in this
disclosure is known in the art. Lubricating co-base oils that are
useful in the present disclosure are both natural oils, and
synthetic oils, and unconventional oils (or mixtures thereof) can
be used unrefined, refined, or rerefined (the latter is also known
as reclaimed or reprocessed oil). Unrefined oils are those obtained
directly from a natural or synthetic source and used without added
purification. These include shale oil obtained directly from
retorting operations, petroleum oil obtained directly from primary
distillation, and ester oil obtained directly from an
esterification process. Refined oils are similar to the oils
discussed for unrefined oils except refined oils are subjected to
one or more purification steps to improve at least one lubricating
oil property. One skilled in the art is familiar with many
purification processes. These processes include solvent extraction,
secondary distillation, acid extraction, base extraction,
filtration, and percolation. Rerefined oils are obtained by
processes analogous to refined oils but using an oil that has been
previously used as a feed stock.
[0028] Groups I, II, III, IV and V are broad base oil stock
categories developed and defined by the American Petroleum
Institute (API Publication 1509; www.API.org) to create guidelines
for lubricant base oils. Group I base stocks have a viscosity index
of between 80 to 120 and contain greater than 0.03% sulfur and/or
less than 90% saturates. Group II base stocks have a viscosity
index of between 80 to 120, and contain less than or equal to 0.03%
sulfur and greater than or equal to 90% saturates. Group III stocks
have a viscosity index greater than 120 and contain less than or
equal to 0.03% sulfur and greater than 90% saturates. Group IV
includes polyalphaolefins (PAO). Group V base stock includes base
stocks not included in Groups I-IV. Table 1 below summarizes
properties of each of these five groups.
TABLE-US-00001 TABLE 1 Base Oil Properties Viscosity Saturates
Sulfur Index Group I <90 and/or >0.03% and .gtoreq.80 and
<120 Group II .gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and
<120 Group III .gtoreq.90 and .ltoreq.0.03% and .gtoreq.120
Group IV Includes polyalphaolefins (PAO) and GTL products Group V
All other base oil stocks not included in Groups I, II, III or
IV
[0029] Natural oils include animal oils, vegetable oils (castor oil
and lard oil, for example), and mineral oils. Animal and vegetable
oils possessing favorable thermal oxidative stability can be used.
Of the natural oils, mineral oils are preferred. Mineral oils vary
widely as to their crude source, for example, as to whether they
are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils
derived from coal or shale are also useful. Natural oils vary also
as to the method used for their production and purification, for
example, their distillation range and whether they are straight run
or cracked, hydrorefined, or solvent extracted.
[0030] Group II and/or Group III hydroprocessed or hydrocracked
basestocks, including synthetic oils such as polyalphaolefins,
alkyl aromatics and synthetic esters are also well known basestock
oils.
[0031] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
for example). Polyalphaolefin (PAO) oil base stocks are commonly
used synthetic hydrocarbon oil. By way of example, PAOs derived
from C.sub.8, C.sub.10, C.sub.12, C.sub.14 olefins or mixtures
thereof may be utilized. See U.S. Pat. Nos. 4,956,122; 4,827,064;
and 4,827,073.
[0032] The number average molecular weights of the PAOs, which are
known materials and generally available on a major commercial scale
from suppliers such as ExxonMobil Chemical Company, Chevron
Phillips Chemical Company, BP, and others, typically vary from 250
to 3,000, although PAO's may be made in viscosities up to 100 cSt
(100.degree. C.). The PAOs are typically comprised of relatively
low molecular weight hydrogenated polymers or oligomers of
alphaolefins which include, but are not limited to, C.sub.2 to
C.sub.32 alphaolefins with the C.sub.8 to C.sub.16 alphaolefins,
such as 1-octene, 1-decene, 1-dodecene and the like, being
preferred. The preferred polyalphaolefins are poly-1-octene,
poly-1-decene and poly-1-dodecene and mixtures thereof and mixed
olefin-derived polyolefins. However, the dimers of higher olefins
in the range of C.sub.14 to C.sub.18 may be used to provide low
viscosity base stocks of acceptably low volatility. Depending on
the viscosity grade and the starting oligomer, the PAOs may be
predominantly trimers and tetramers of the starting olefins, with
minor amounts of the higher oligomers, having a viscosity range of
1.5 to 12 cSt. PAO fluids of particular use may include 3.0 cSt,
3.4 cSt, and/or 3.6 cSt and combinations thereof. Bi-modal mixtures
of PAO fluids having a viscosity range of 1.5 to 100 cSt may be
used if desired.
[0033] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. Nos. 4,149,178 or 3,382,291 may be
conveniently used herein. Other descriptions of PAO synthesis are
found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C.sub.14 to C.sub.18
olefins are described in U.S. Pat. No. 4,218,330.
[0034] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269, the disclosure of which is incorporated
herein by reference in its entirety. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Each of the aforementioned patents is incorporated
herein in their entirety. Particularly favorable processes are
described in European Patent Application Nos. 464546 and 464547,
also incorporated herein by reference. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. Nos. 4,594,172
and 4,943,672, the disclosures of which are incorporated herein by
reference in their entirety.
[0035] Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax derived
base oils, and other wax-derived hydroisomerized (wax isomerate)
base oils can be advantageously used in the instant disclosure, and
may have useful kinematic viscosities at 100.degree. C. of 3 cSt to
50 cSt, preferably 3 cSt to 30 cSt, more preferably 3.5 cSt to 25
cSt, as exemplified by GTL 4 with kinematic viscosity of 4.0 cSt at
100.degree. C. and a viscosity index of 131. These Gas-to-Liquids
(GTL) base oils, Fischer-Tropsch wax derived base oils, and other
wax-derived hydroisomerized base oils may have useful pour points
of -20.degree. C. or lower, and under some conditions may have
advantageous pour points of -25.degree. C. or lower, with useful
pour points of -30.degree. C. to -40.degree. C. or lower. Useful
compositions of Gas-to-Liquids (GTL) base oils, Fischer-Tropsch wax
derived base oils, and wax-derived hydroisomerized base oils are
recited in U.S. Pat. Nos. 6,080,301; 6,090,989, and 6,165,949 for
example, and are incorporated herein in their entirety by
reference.
[0036] The hydrocarbyl aromatics can be used as base oil or base
oil component and can be any hydrocarbyl molecule that contains at
least 5% of its weight derived from an aromatic moiety such as a
benzenoid moiety or naphthenoid moiety, or their derivatives. These
hydrocarbyl aromatics include alkyl benzenes, alkyl naphthalenes,
alkyl diphenyl oxides, alkyl naphthols, alkyl diphenyl sulfides,
alkylated bis-phenol A, alkylated thiodiphenol, and the like. The
aromatic can be mono-alkylated, dialkylated, polyalkylated, and the
like. The aromatic can be mono- or poly-functionalized. The
hydrocarbyl groups can also be comprised of mixtures of alkyl
groups, alkenyl groups, alkynyl, cycloalkyl groups, cycloalkenyl
groups and other related hydrocarbyl groups. The hydrocarbyl groups
can range from C.sub.6 up to C.sub.60 with a range of C.sub.8 to
C.sub.20 often being preferred. A mixture of hydrocarbyl groups is
often preferred, and up to three such substituents may be present.
The hydrocarbyl group can optionally contain sulfur, oxygen, and/or
nitrogen containing substituents. The aromatic group can also be
derived from natural (petroleum) sources, provided at least 5% of
the molecule is comprised of an above-type aromatic moiety.
Viscosities at 100.degree. C. of approximately 3 cSt to 50 cSt are
preferred, with viscosities of approximately 3.4 cSt to 20 cSt
often being more preferred for the hydrocarbyl aromatic component.
In one embodiment, an alkyl naphthalene where the alkyl group is
primarily comprised of 1-hexadecene is used. Other alkylates of
aromatics can be advantageously used. Naphthalene or methyl
naphthalene, for example, can be alkylated with olefins such as
octene, decene, dodecene, tetradecene or higher, mixtures of
similar olefins, and the like. Useful concentrations of hydrocarbyl
aromatic in a lubricant oil composition can be 2% to 25%,
preferably 4% to 20%, and more preferably 4% to 15%, depending on
the application.
[0037] Alkylated aromatics such as the hydrocarbyl aromatics of the
present disclosure may be produced by well-known Friedel-Crafts
alkylation of aromatic compounds. See Friedel-Crafts and Related
Reactions, Olah, G. A. (ed.), Inter-science Publishers, New York,
1963. For example, an aromatic compound, such as benzene or
naphthalene, is alkylated by an olefin, alkyl halide or alcohol in
the presence of a Friedel-Crafts catalyst. See Friedel-Crafts and
Related Reactions, Vol. 2, part 1, chapters 14, 17, and 18, See
Olah, G. A. (ed.), Inter-science Publishers, New York, 1964. Many
homogeneous or heterogeneous, solid catalysts are known to one
skilled in the art. The choice of catalyst depends on the
reactivity of the starting materials and product quality
requirements. For example, strong acids such as AlCl.sub.3,
BF.sub.3, or HF may be used. In some cases, milder catalysts such
as FeCl.sub.3 or SnCl.sub.4 are preferred. Newer alkylation
technology uses zeolites or solid super acids.
[0038] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0039] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols, e.g.,
neopentyl glycol, trimethylol ethane,
2-methyl-2-propyl-1,3-propanediol, trimethylol propane,
pentaerythritol and dipentaerythritol) with alkanoic acids
containing at least 4 carbon atoms, preferably C.sub.5 to C.sub.30
acids such as saturated straight chain fatty acids including
caprylic acid, capric acid, lauric acid, myristic acid, palmitic
acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures of any of these materials.
[0040] Suitable synthetic ester components include the esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from 5 to 10 carbon atoms. These
esters are widely available commercially, for example, the Mobil
P-41 and P-51 esters of ExxonMobil Chemical Company.
[0041] Also useful are esters derived from renewable material such
as coconut, palm, rapeseed, soy, sunflower and the like. These
esters may be monoesters, di-esters, polyol esters, complex esters,
or mixtures thereof. These esters are widely available
commercially, for example, the Mobil P-51 ester of ExxonMobil
Chemical Company.
[0042] Hydraulic system formulations containing renewable esters
are included in this disclosure. For such formulations, the
renewable content of the ester is typically greater than 70 weight
percent, preferably more than 80 weight percent and most preferably
more than 90 weight percent.
[0043] Other useful fluids of lubricating viscosity include
non-conventional or unconventional base stocks that have been
processed, preferably catalytically, or synthesized to provide high
performance lubrication characteristics.
[0044] Non-conventional or unconventional base stocks/base oils
include one or more of a mixture of base stock(s) derived from one
or more Gas-to-Liquids (GTL) materials, as well as
isomerate/isodewaxate base stock(s) derived from natural wax or
waxy feeds, mineral and or non-mineral oil waxy feed stocks such as
slack waxes, natural waxes, and waxy stocks such as gas oils, waxy
fuels hydrocracker bottoms, waxy raffinate, hydrocrackate, thermal
crackates, or other mineral, mineral oil, or even non-petroleum oil
derived waxy materials such as waxy materials received from coal
liquefaction or shale oil, and mixtures of such base stocks.
[0045] GTL materials are materials that are derived via one or more
synthesis, combination, transformation, rearrangement, and/or
degradation/deconstructive processes from gaseous carbon-containing
compounds, hydrogen-containing compounds and/or elements as feed
stocks such as hydrogen, carbon dioxide, carbon monoxide, water,
methane, ethane, ethylene, acetylene, propane, propylene, propyne,
butane, butylenes, and butynes. GTL base stocks and/or base oils
are GTL materials of lubricating viscosity that are generally
derived from hydrocarbons; for example, waxy synthesized
hydrocarbons, that are themselves derived from simpler gaseous
carbon-containing compounds, hydrogen-containing compounds and/or
elements as feed stocks. GTL base stock(s) and/or base oil(s)
include oils boiling in the lube oil boiling range (1)
separated/fractionated from synthesized GTL materials such as, for
example, by distillation and subsequently subjected to a final wax
processing step which involves either or both of a catalytic
dewaxing process, or a solvent dewaxing process, to produce lube
oils of reduced/low pour point; (2) synthesized wax isomerates,
comprising, for example, hydrodewaxed or hydroisomerized cat and/or
solvent dewaxed synthesized wax or waxy hydrocarbons; (3)
hydrodewaxed or hydroisomerized cat and/or solvent dewaxed
Fischer-Tropsch (F-T) material (i.e., hydrocarbons, waxy
hydrocarbons, waxes and possible analogous oxygenates); preferably
hydrodewaxed or hydroisomerized/followed by cat and/or solvent
dewaxing dewaxed F-T waxy hydrocarbons, or hydrodewaxed or
hydroisomerized/followed by cat (or solvent) dewaxing dewaxed, F-T
waxes, or mixtures thereof.
[0046] GTL base stock(s) and/or base oil(s) derived from GTL
materials, especially, hydrodewaxed or hydroisomerized/followed by
cat and/or solvent dewaxed wax or waxy feed, preferably F-T
material derived base stock(s) and/or base oil(s), are
characterized typically as having kinematic viscosities at
100.degree. C. of from 2 mm.sup.2/s to 50 mm.sup.2/s (ASTM D445).
They are further characterized typically as having pour points of
-5.degree. C. to -40.degree. C. or lower (ASTM D97). They are also
characterized typically as having viscosity indices of 80 to 140 or
greater (ASTM D2270).
[0047] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) typically have very low sulfur and
nitrogen content, generally containing less than 10 ppm, and more
typically less than 5 ppm of each of these elements. The sulfur and
nitrogen content of GTL base stock(s) and/or base oil(s) obtained
from F-T material, especially F-T wax, is essentially nil. In
addition, the absence of phosphorous and aromatics make this
materially especially suitable for the formulation of low SAP
products.
[0048] The term GTL base stock and/or base oil and/or wax isomerate
base stock and/or base oil is to be understood as embracing
individual fractions of such materials of wide viscosity range as
recovered in the production process, mixtures of two or more of
such fractions, as well as mixtures of one or two or more low
viscosity fractions with one, two or more higher viscosity
fractions to produce a blend wherein the blend exhibits a target
kinematic viscosity.
[0049] The GTL material, from which the GTL base stock(s) and/or
base oil(s) is/are derived is preferably an F-T material (i.e.,
hydrocarbons, waxy hydrocarbons, wax).
[0050] In addition, the GTL base stock(s) and/or base oil(s) are
typically highly paraffinic (>90% saturates), and may contain
mixtures of monocycloparaffins and multicycloparaffins in
combination with non-cyclic isoparaffins. The ratio of the
naphthenic (i.e., cycloparaffin) content in such combinations
varies with the catalyst and temperature used. Further, GTL base
stock(s) and/or base oil(s) and hydrodewaxed, or
hydroisomerized/cat (and/or solvent) dewaxed base stock(s) and/or
base oil(s) typically have very low sulfur and nitrogen content,
generally containing less than 10 ppm, and more typically less than
5 ppm of each of these elements. The sulfur and nitrogen content of
GTL base stock(s) and/or base oil(s) obtained from F-T material,
especially F-T wax, is essentially nil. In addition, the absence of
phosphorous and aromatics make this material especially suitable
for the formulation of low sulfur, sulfated ash, and phosphorus
(low SAP) products.
[0051] Co-base oils for use in the formulated lubricating
compositions of the present disclosure are any of the variety of
oils corresponding to API Group I, Group II, Group III, Group IV,
and Group V oils and mixtures thereof, preferably API Group II,
Group III, Group IV, and Group V oils and mixtures thereof, more
preferably the Group III to Group V base oils due to their
exceptional volatility, stability, viscometric and cleanliness
features. Minor quantities of Group I stock, such as the amount
used to dilute additives for blending into formulated lube oil
products, can be tolerated but should be kept to a minimum, i.e.
amounts only associated with their use as diluent/carrier oil for
additives used on an "as-received" basis. Even in regard to the
Group II stocks, it is preferred that the Group II stock be in the
higher quality range associated with that stock, i.e., a Group II
stock having a viscosity index in the range 100<VI<120.
[0052] As described herein, the lubricating composition of this
disclosure preferably comprises a Group II co-base stock. The Group
II co-base stock preferably has a viscosity from 6.5 to 11.0
mm.sup.2/s at 40.degree. C., is isoparaffinic, and is produced from
natural gas and subsequent wax isomerization. Illustrative Group II
co-base stocks include, for example, Shell QHVI 3, and the
like.
[0053] Also, as described herein, the lubricating composition of
this disclosure preferably comprises a heavy Group II co-base
stock. The heavy Group II co-base stock preferably has a viscosity
from 10.0 to 13.0 mm.sup.2/s at 100.degree. C., a viscosity index
greater than 90, a sulfur content less than 0.001 weight percent,
and saturates content greater than 99%. Illustrative Group II
co-base stocks include, for example, EHC 110 and Flint Hills
600-HC.
[0054] The co-base oil constitutes the minor component of the
lubricant composition of the present disclosure and typically is
present in an amount ranging from 0.1 to 20 weight percent,
preferably from 0.5 to 15 weight percent, and more preferably from
1.0 to 10.0 weight percent, based on the total weight of the
lubricant composition. The co-base oil may be selected from any of
the synthetic or natural oils typically used in hydraulic systems.
Mixtures of synthetic and natural base oils may be used if desired.
Bi-modal mixtures of Group I, II, III, IV, and/or V base stocks may
be used if desired.
Other Additives
[0055] The lubricating compositions useful in the present
disclosure may additionally contain one or more of the other
commonly used lubricating oil performance additives including but
not limited to antiwear agents, dispersants, corrosion inhibitors,
rust inhibitors, metal deactivators, extreme pressure additives,
anti-seizure agents, wax modifiers, viscosity index improvers,
viscosity modifiers, fluid-loss additives, seal compatibility
agents, lubricity agents, solubility improvers, anti-staining
agents, chromophoric agents, defoamants, demulsifiers, emulsifiers,
densifiers, wetting agents, gelling agents, tackiness agents,
colorants, and others. For a review of many commonly used
additives, see Klamann in Lubricants and Related Products, Verlag
Chemie, Deerfield Beach, Fla.; ISBN 0-89573-177-0. Reference is
also made to "Lubricant Additives" by M. W. Ranney, published by
Noyes Data Corporation of Parkridge, N.J. (1973); see also U.S.
Pat. No. 7,704,930, the disclosure of which is incorporated herein
in its entirety.
[0056] Many of the additives which may be used are described in
greater detail below and these additives may be added separately or
as an additive package. Additive packages may contain one or more
of the additives described herein and may also contain some amount
of diluent oil and/or solvent. An additive package may be added to
the compositions of the disclosure such that they are present at
0.2 to 4.0 wt %, 0.5 to 3.0 wt %, or 0.6 to 2.0 wt %. The types and
quantities of performance additives used in combination with the
instant disclosure in lubricant compositions are not limited by the
examples shown herein as illustrations.
Antiwear Additive
[0057] A metal alkylthiophosphate and more particularly a metal
dialkyl dithio phosphate in which the metal constituent is zinc, or
zinc dialkyl dithio phosphate (ZDDP) is a useful component of the
lubricating compositions of this disclosure. ZDDP can be derived
from primary alcohols, secondary alcohols or mixtures thereof. ZDDP
compounds generally are of the formula
Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.2 where R.sup.1 and R.sup.2 are
C.sub.1-C.sub.18 alkyl groups, preferably C.sub.2-C.sub.12 alkyl
groups. These alkyl groups may be straight chain or branched. Alkyl
aryl groups may also be used.
[0058] Preferable zinc dithiophosphates which are commercially
available include secondary zinc dithiophosphates such as those
available from for example, The Lubrizol Corporation under the
trade designations "LZ 1095", "LZ 677A" and "LZ 1371", from for
example Chevron Oronite under the trade designation "OLOA 262" and
from for example Afton Chemical under the trade designation "HITEC
7169".
[0059] The ZDDP is typically used in amounts of from 0.4 weight
percent to 1.2 weight percent, preferably from 0.5 weight percent
to 1.0 weight percent, and more preferably from 0.6 weight percent
to 0.8 weight percent, based on the total weight of the lubricating
composition, although more or less can often be used
advantageously. Preferably, the ZDDP is a secondary ZDDP and
present in an amount of from 0.6 to 1.0 weight percent of the total
weight of the lubricating composition.
[0060] Low phosphorus formulations are included in this disclosure.
For such formulations, the phosphorus content is typically less
than 0.12 weight percent preferably less than 0.10 weight percent
and most preferably less than 0.085 weight percent.
[0061] Metal-free phosphorus-containing compounds are also useful
antiwear additives in accordance with this disclosure. A phosphate
ester or salt may be a monohydrocarbyl, dihydrocarbyl or a
trihydrocarbyl phosphate, wherein each hydrocarbyl group is
saturated. In one embodiment, each hydrocarbyl group independently
contains from 8 to 30, or from 12 up to 28, or from 14 up to 24, or
from 14 up to 18 carbons atoms. In one embodiment, the hydrocarbyl
groups are alkyl groups. Examples of hydrocarbyl groups include
tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl
groups and mixtures thereof.
[0062] A phosphate ester or salt is a phosphorus acid ester can be
prepared by reacting one or more phosphorus acid or anhydride with
a saturated alcohol. The phosphorus acid or anhydride is generally
an inorganic phosphorus reagent, such as phosphorus pentoxide,
phosphorus trioxide, phosphorus tetroxide, phosphorous acid,
phosphoric acid, phosphorus halide, lower phosphorus esters, or a
phosphorus sulfide, including phosphorus pentasulfide, and the
like. Lower phosphorus acid esters generally contain from 1 to 7
carbon atoms in each ester group. The alcohols used to prepare the
phosphorus acid esters or salts include, for example, commercially
available alcohols and alcohol mixtures including Alfol 1218 (a
mixture of synthetic, primary, straight-chain alcohols containing
12 to 18 carbon atoms); Alibi 20+ alcohols (mixtures of
C.sub.18-C.sub.28 primary alcohols having mostly C.sub.20 alcohols
as determined by GLC (gas-liquid-chromatography)); and Alfo122+
alcohols (C.sub.18-C.sub.28 primary alcohols containing primarily
C.sub.22 alcohols). Alfol alcohols are available from Continental
Oil Company. Another example of a commercially available alcohol
mixture is Adol 60 (75% by weight of a straight chain C.sub.22
primary alcohol, 15% of a C.sub.20 primary alcohol and 8% of
C.sub.18 and C.sub.24 alcohols). The Adol alcohols are marketed by
Ashland Chemical.
[0063] A variety of mixtures of monohydric fatty alcohols derived
from naturally occurring triglycerides and ranging in chain length
from C.sub.8-C.sub.18 are available from Procter & Gamble
Company. These mixtures contain various amounts of fatty alcohols
containing 12, 14, 16, or 18 carbon atoms. For example, CO-1214 is
a fatty alcohol mixture containing 0.5% of C.sub.10 alcohol, 66.0%
of C.sub.12 alcohol, 26.0% of C.sub.14 alcohol and 6.5% of C.sub.16
alcohol.
[0064] Another group of commercially available mixtures include the
"Neodol" products available from Shell Chemical Co. For example,
Neodol 23 is a mixture of C.sub.12 and C.sub.13 alcohols; Neodol 25
is a mixture of C.sub.12-C.sub.15 alcohols; and Neodol 45 is a
mixture of C.sub.14-C.sub.15 linear alcohols. The phosphate
contains from 14 to 18 carbon atoms in each hydrocarbyl group. The
hydrocarbyl groups of the phosphate are generally derived from a
mixture of fatty alcohols having from 14 up to 18 carbon atoms. The
hydrocarbyl phosphate may also be derived from a fatty vicinal
diol. Fatty vicinal diols include those available from Ashland Oil
under the general trade designation Adol 114 and Adol 158. The
former is derived from a straight chain alpha olefin fraction of
C.sub.11-C.sub.14, and the latter is derived from a
C.sub.15-C.sub.18 fraction.
[0065] The phosphate salts may be prepared by reacting an acidic
phosphate ester with an amine compound or a metallic base to form
an amine or a metal salt. The amines may be monoamines or
polyamines. Useful amines include those amines disclosed in U.S.
Pat. No. 4,234,435.
[0066] The monoamines generally contain a hydrocarbyl group which
contains from 1 to 30 carbon atoms, or from 1 to 12, or from 1 to
6. Examples of primary monoamines useful in the present disclosure
include methylamine, ethylamine, propylamine, butylamine,
cyclopentylamine, cyclohexylamine, octylamine, dodecylamine,
allylamine, cocoamine, stearylamine, and lauryl amine. Examples of
secondary monoamines include dimethylamine, diethylamine,
dipropylamine, dibutylamine, dicyclopentylamine, dicyclohexylamine,
methylbutylamine, ethylhexylamine, etc.
[0067] An amine is a fatty (C.sub.8-C.sub.30) amine which includes
n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine,
n-hexadecylamine, n-octadecytamine, oleyamine, etc. Also useful
fatty amines include commercially available fatty amines such as
"Armeen" amines (products available from Akzo Chemicals, Chicago,
Ill.), such Armeen C, Armeen O, Armeen O L, Armeen T, Armeen H T,
Armeen S and Armeen S D, wherein the letter designation relates to
the fatty group, such as coco, oleyl, tallow, or stearyl
groups.
[0068] Other useful amines include primary ether amines, such as
those represented by the formula, R''(OR').times.NH.sub.2, wherein
R' is a divalent alkylene group having 2 to 6 carbon atoms; x is a
number from one to 150, or from one to five, or one; and R'' is a
hydrocarbyl group of 5 to 150 carbon atoms. An example of an ether
amine is available under the name SURFAM.RTM. amines produced and
marketed by Mars is Chemical Company, Atlanta, Ga. Preferred
etheramines are exemplified by those identified as SURFAM P14B
(decyloxypropylamine), SURFAM P16A (linear C.sub.16), SURFAM P17B
(tridecyloxypropylamine). The carbon chain lengths (i.e., C.sub.14,
etc.) of the SURFAMS described above and used hereinafter are
approximate and include the oxygen ether linkage.
[0069] An amine is a tertiary-aliphatic primary amine. Generally,
the aliphatic group, preferably an alkyl group, contains from 4 to
30, or from 6 to 24, or from 8 to 22 carbon atoms. Usually the
tertiary alkyl primary amines are monoamines the alkyl group is a
hydrocarbyl group containing from one to 27 carbon atoms and R6 is
a hydrocarbyl group containing from 1 to 12 carbon atoms. Such
amines are illustrated by tert-butylamine, tert-hexylamine,
1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine,
tert-dodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecytamine, tert-tetracosanylamine, and
tert-octacosanylamine. Mixtures of tertiary aliphatic amines may
also be used in preparing the phosphate salt. Illustrative of amine
mixtures of this type are "Primene 81R" which is a mixture of
C.sub.11-C.sub.14 tertiary alkyl primary amines and "Primene JMT"
which is a similar mixture of C.sub.18-C.sub.22 tertiary alkyl
primary amities (both are available from Rohm and Haas Company).
The tertiary aliphatic primary amines and methods for their
preparation are known to those of ordinary skill in the art. An
amine can be a heterocyclic polyamine. The heterocyclic polyamines
include aziridines, azetidines, azolidines, tetra- and
dihydropyridines, pyrroles, indoles, piperidines, imidazoles, di-
and tetra-hydroimidazoles, piperazines, isoindoles, purines,
morpholines, thiomorpholines, N-aminoalkylmorpholines,
N-aminoalklthiomorpholines, N-aminoalkyl-piperazines,
N,N'-diaminoalkylpiperazines, azepines, azocines, azonines,
azecines and tetra-, di- and perhydro derivatives of each of the
above and mixtures of two or more of these heterocyclic amines.
Preferred heterocyclic amines are the saturated 5- and 6-membered
heterocyclic amines containing only nitrogen, oxygen and/or sulfur
in the hetero ring, especially the piperidines, piperazines,
thiomorpholines, morpholines, pyrrolidines, and the like.
Piperidine, aminoalkyl substituted piperidines, piperazine,
aminoalkyl substituted piperazines, morpholine, aminoalkyl
substituted morpholines, pyrrolidine, and aminoalkyl-substituted
pyrrolidines, are especially preferred. Usually the aminoalkyl
substituents are substituted on a nitrogen atom forming part of the
hetero ring. Specific examples of such heterocyclic amines include
N-aminopropylmorpholine, N-aminoethylpiperazine, and
N,N'-diaminoethylpiperazine. Hydroxy heterocyclic polyamines are
also useful. Examples include N-(2-hydroxyethyl)cyclohexylamine,
3-hydroxycyclopentylamine, parahydroxyaniline,
N-hydroxyethylpiperazine, and the like.
[0070] The metal free phosphorus containing compounds are typically
used in amounts of from 0.4 weight percent to 1.2 weight percent,
preferably from 0.5 weight percent to 1.0 weight percent, and more
preferably from 0.6 weight percent to 0.8 weight percent, based on
the total weight of the lubricating composition, although more or
less can often be used advantageously.
Viscosity Index Improvers
[0071] Viscosity index improvers (also known as VI improvers,
viscosity modifiers, and viscosity improvers) can be included in
the lubricant compositions of this disclosure.
[0072] Viscosity index improvers provide lubricants with high and
low temperature operability. These additives impart shear stability
at elevated temperatures and acceptable viscosity at low
temperatures. Suitable viscosity index improvers include high
molecular weight hydrocarbons, polyesters and viscosity index
improver dispersants that function as both a viscosity index
improver and a dispersant. Typical molecular weights of these
polymers are between 10,000 to 1,500,000, more typically 20,000 to
1,200,000, even more typically between 50,000 and 1,000,000, and
yet even more typically between 50,000 and 200,000. Viscosity index
improvers may also be considered multifunctional. For example
multifunctional viscosity index improvers can also function as
dispersants. Examples of such viscosity index improvers are
polyisobutylene, copolymers of ethylene and propylene and higher
alpha-olefins, polymethacrylates, polyalkylmethacrylates,
methacrylate copolymers, copolymers of an unsaturated dicarboxylic
acid and a vinyl compound, inter polymers of styrene and acrylic
esters, and partially hydrogenated copolymers of styrene/isoprene,
styrene/butadiene, and isoprene/butadiene, as well as the partially
hydrogenated homopolymers of butadiene and isoprene and
isoprene/divinylbenzene.
[0073] Other examples of suitable viscosity index improvers are
linear or star-shaped polymers and copolymers of methacrylate,
butadiene, olefins, or alkylated styrenes. Polyisobutylene is a
commonly used viscosity index improver. Another suitable viscosity
index improver is polymethacrylate (copolymers of various chain
length alkyl methacrylates, for example), some formulations of
which also serve as pour point depressants. Other suitable
viscosity index improvers include copolymers of ethylene and
propylene, hydrogenated block copolymers of styrene and isoprene,
and polyacrylates (copolymers of various chain length acrylates,
for example). Specific examples include styrene-isoprene or
styrene-butadiene based polymers of 50,000 to 200,000 molecular
weight.
[0074] Suitable polyalkyl methacrylate viscosity index improvers
include, for example, homopolymers prepared from methacrylic acid
such as poly methyl methacrylate, poly ethyl methacrylate, poly
propyl methacrylate, poly butyl methacrylate, poly hexyl
methacrylate, poly octyl methacrylate, poly 2-ethylhexyl
methacrylate, poly decyl methacrylate, poly undecyl methacrylate,
poly dodecyl methacrylate, poly tridecyl methacrylate, poly
tetradecyl methacrylate, poly pentadecyl methacrylate, poly
hexadecyl methacrylate, or mixtures thereof.
[0075] Other suitable polyalkyl methacrylate viscosity index
improvers include, for example, copolymers (typically an
interpolymers) of (i) a vinyl aromatic monomer; and (ii) an
unsaturated carboxylic acid, anhydride, or derivatives thereof, (c)
an interpolymer of (i) an alpha-olefin; and (ii) an unsaturated
carboxylic acid, anhydride, or derivatives thereof, or (d) mixtures
thereof. The unsaturated carboxylic acid, anhydride or derivatives
thereof, include in addition to methacrylic acid, others such as
acrylic acid, butenoic acid, maleic acid, maleic anhydride, fumaric
acid, itaconic acid, or mixtures thereof. In one embodiment the
unsaturated carboxylic acid or derivatives thereof includes
methacrylic acid and at least one of maleic acid, maleic anhydride,
fumaric acid, itaconic acid, or mixtures thereof. In another
embodiment, the unsaturated carboxylic acid or derivatives thereof
includes methacrylic acid and at least one of maleic acid or maleic
anhydride.
[0076] Olefin copolymers, are commercially available from Chevron
Oronite Company LLC under the trade designation "PARATONE.RTM."
(such as "PARATONE.RTM. 8921" and "PARATONE.RTM. 8941"); from Afton
Chemical Corporation under the trade designation "HiTEC.RTM." (such
as "HiTEC.RTM. 5850B"; and from The Lubrizol Corporation under the
trade designation "Lubrizol.RTM. 7067C". Polyisoprene polymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV200"; diene-styrene copolymers are
commercially available from Infineum International Limited, e.g.
under the trade designation "SV 260". Polyalkyl methacrylates
(PAMA) are commercially available from Evonik Oil Additives, Inc.
USA under the trade designation VISCOPLEX.RTM. 8-219. Other
examples of commercially available viscosity index improvers, such
as polymethacrylates are the Viscoplex TM series from Evonik,
Lz77XXTM series from Lubrizol, the Hitec 57XXTM series from Afton.
Other commercially available viscosity index improvers Lz 7702,
7720, 7727, 7773, 7725, and 7789; Viscoplex 8-890, 8-219, and
4-708, and Hitec 6708 and 5789.
[0077] In an embodiment of this disclosure, the viscosity index
improvers may be used in an amount of less than 15 weight percent,
preferably less than 10 weight percent, based on the total weight
of the formulated oil or lubricating composition.
[0078] In another embodiment of this disclosure, the viscosity
index improvers may be used in an amount of from 0.25 to 15.0
weight percent, preferably 0.15 to 10.0 weight percent, and more
preferably 0.05 to 8.0 weight percent, based on the total weight of
the formulated oil or lubricating composition.
Dispersants
[0079] During operation of a hydraulic system, oil-insoluble
oxidation byproducts are produced. Dispersants help keep these
byproducts in solution, thus diminishing their deposition on metal
surfaces. Dispersants used in the formulation of the lubricating
composition may be ashless or ash-forming in nature. Preferably,
the dispersant is ashless. So-called ashless dispersants are
organic materials that form substantially no ash upon combustion.
For example, non-metal-containing or borated metal-free dispersants
are considered ashless. In contrast, metal-containing detergents
form ash upon combustion.
[0080] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorus. Typical hydrocarbon chains contain
50 to 400 carbon atoms.
[0081] Chemically, many dispersants may be characterized as
phenates, sulfonates, sulfurized phenates, salicylates,
naphthenates, stearates, carbamates, thiocarbamates, phosphorus
derivatives. A particularly useful class of dispersants are the
alkenylsuccinic derivatives, typically produced by the reaction of
a long chain hydrocarbyl substituted succinic compound, usually a
hydrocarbyl substituted succinic anhydride, with a polyhydroxy or
polyamino compound. The long chain hydrocarbyl group constituting
the oleophilic portion of the molecule which confers solubility in
the oil, is normally a polyisobutylene group. Many examples of this
type of dispersant are well known commercially and in the
literature. Exemplary U.S. patents describing such dispersants are
U.S. Pat. Nos. 3,172,892; 3,215,707; 3,219,666; 3,316,177;
3,341,542; 3,444,170; 3,454,607; 3,541,012; 3,630,904; 3,632,511;
3,787,374 and 4,234,435. Other types of dispersant are described in
U.S. Pat. Nos. 3,036,003; 3,200,107; 3,254,025; 3,275,554;
3,438,757; 3,454,555; 3,565,804; 3,413,347; 3,697,574; 3,725,277;
3,725,480; 3,726,882; 4,454,059; 3,329,658; 3,449,250; 3,519,565;
3,666,730; 3,687,849; 3,702,300; 4,100,082; 5,705,458. A further
description of dispersants may be found, for example, in European
Patent Application No. 471 071, to which reference is made for this
purpose.
[0082] Hydrocarbyl-substituted succinic acid and
hydrocarbyl-substituted succinic anhydride derivatives are useful
dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of a
hydrocarbon-substituted succinic acid compound preferably having at
least 50 carbon atoms in the hydrocarbon substituent, with at least
one equivalent of an alkylene amine are particularly useful.
[0083] Succinimides are formed by the condensation reaction between
hydrocarbyl substituted succinic anhydrides and amines. Molar
ratios can vary depending on the polyamine. For example, the molar
ratio of hydrocarbyl substituted succinic anhydride to TEPA can
vary from 1:1 to 5:1. Representative examples are shown in U.S.
Pat. Nos. 3,087,936; 3,172,892; 3,219,666; 3,272,746; 3,322,670;
and 3,652,616, 3,948,800; and Canada Patent No. 1,094,044.
[0084] Succinate esters are formed by the condensation reaction
between hydrocarbyl substituted succinic anhydrides and alcohols or
polyols. Molar ratios can vary depending on the alcohol or polyol
used. For example, the condensation product of a hydrocarbyl
substituted succinic anhydride and pentaerythritol is a useful
dispersant.
[0085] Succinate ester amides are formed by condensation reaction
between hydrocarbyl substituted succinic anhydrides and alkanol
amines. For example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305.
[0086] The molecular weight of the hydrocarbyl substituted succinic
anhydrides used in the preceding paragraphs will typically range
between 800 and 2,500 or more. The above products can be
post-reacted with various reagents such as sulfur, oxygen,
formaldehyde, carboxylic acids such as oleic acid. The above
products can also be post reacted with boron compounds such as
boric acid, borate esters or highly borated dispersants, to form
borated dispersants generally having from 0.1 to 5 moles of boron
per mole of dispersant reaction product.
[0087] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, which is incorporated herein by reference. Process aids
and catalysts, such as oleic acid and sulfonic acids, can also be
part of the reaction mixture. Molecular weights of the alkylphenols
range from 800 to 2,500. Representative examples are shown in U.S.
Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365; 3,756,953;
3,798,165; and 3,803,039.
[0088] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this disclosure can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HN.RTM..sub.2 group-containing reactants.
[0089] Hydrocarbyl substituted amine ashless dispersant additives
are well known to one skilled in the art; see, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197.
[0090] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
500 to 5000 or a mixture of such hydrocarbylene groups, often with
high terminal vinylic groups. Other preferred dispersants include
succinic acid-esters and amides, alkylphenol-polyamine-coupled
Mannich adducts, their capped derivatives, and other related
components. Such additives may be used in an amount of 0.1 to 20
weight percent, preferably 0.5 to 8 weight percent.
[0091] As used herein, the dispersant concentrations are given on
an "as delivered" basis. Typically, the active dispersant is
delivered with a process oil. The "as delivered" dispersant
typically contains from 20 weight percent to 80 weight percent, or
from 40 weight percent to 60 weight percent, of active dispersant
in the "as delivered" dispersant product.
Antioxidants
[0092] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example.
[0093] Useful antioxidants include hindered phenols. These phenolic
antioxidants may be ashless (metal-free) phenolic compounds or
neutral or basic metal salts of certain phenolic compounds. Typical
phenolic antioxidant compounds are the hindered phenolics which are
the ones which contain a sterically hindered hydroxyl group, and
these include those derivatives of dihydroxy aryl compounds in
which the hydroxyl groups are in the o- or p-position to each
other. Typical phenolic antioxidants include the hindered phenols
substituted with C.sub.6+ alkyl groups and the alkylene coupled
derivatives of these hindered phenols. Examples of phenolic
materials of this type 2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl
phenol; 2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant disclosure. Examples of ortho-coupled
phenols include: 2,2'-bis(4-heptyl-6-t-butyl-phenol);
2,2'-bis(4-octyl-6-t-butyl-phenol); and
2,2'-bis(4-dodecyl-6-t-butyl-phenol). Para-coupled bisphenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0094] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10 N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.xR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
20 carbon atoms, and preferably contains from 6 to 12 carbon atoms.
The aliphatic group is a saturated aliphatic group. Preferably,
both R.sup.8 and R.sup.9 are aromatic or substituted aromatic
groups, and the aromatic group may be a fused ring aromatic group
such as naphthyl. Aromatic groups R.sup.8 and R.sup.9 may be joined
together with other groups such as S.
[0095] Typical aromatic amines antioxidants have alkyl substituent
groups of at least 6 carbon atoms. Examples of aliphatic groups
include hexyl, heptyl, octyl, nonyl, and decyl. Generally, the
aliphatic groups will not contain more than 14 carbon atoms. The
general types of amine antioxidants useful in the present
compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present disclosure
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0096] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants.
[0097] Preferred antioxidants include hindered phenols, arylamines.
These antioxidants may be used individually by type or in
combination with one another. Such additives may be used in an
amount of 0.01 to 5 weight percent, preferably 0.01 to 1.5 weight
percent, more preferably zero to less than 1.5 weight percent, most
preferably zero.
Pour Point Depressants (PPDs)
[0098] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
disclosure if desired. These pour point depressant may be added to
lubricating compositions of the present disclosure to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2,721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Such additives may be
used in an amount of 0.01 to 5 weight percent, preferably 0.01 to
1.5 weight percent.
Antifoam Agents
[0099] Antifoam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical antifoam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Antifoam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 weight
percent and often less than 0.1 weight percent.
Corrosion Inhibitors and Antirust Additives
[0100] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available.
[0101] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of 0.01 to 5 weight percent, preferably 0.01
to 1.5 weight percent.
Solubility Improvers
[0102] Solubility improvers are additives that confer solubility to
the oil. A wide variety of these additives are commercially
available. Solubility improvers are liquid with aniline points less
than 115.degree. C., preferably less than 110.degree. C., and more
preferably less than 105.degree. C., compatible with lubricating
base oils. Examples of solubility improvers include mineral oils
and synthetic lubricants such as alkylated aromatics, organic
esters, naphthenics, and the like. The solubility improvers can be
used in an amount of from 0 to 20 weight percent, preferably from 0
to 15 weight percent, and more preferably from 0 to 10 weight
percent.
[0103] When lubricating compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
disclosure are shown in Table 2 below.
[0104] It is noted that many of the additives are shipped from the
additive manufacturer as a concentrate, containing one or more
additives together, with a certain amount of base oil diluents.
Accordingly, the weight amounts in the table below, as well as
other amounts mentioned herein, are directed to the amount of
active ingredient (that is the non-diluent portion of the
ingredient). The weight percent (wt %) indicated below is based on
the total weight of the lubricating composition.
TABLE-US-00002 TABLE 2 Typical Amounts of Other Lubricating
Components Approximate Approximate Compound wt % (Useful) wt %
(Preferred) Dispersant .sup. 0.1-1.0 0.1-1.0 Antioxidant 0.1-5
0.1-1.5 Pour Point Depressant 0.0-5 0.01-1.5 (PPD) Antifoam Agent
0.001-3 0.001-0.15 Viscosity Index Improver 0.1-10.0 0.1-8.0 (solid
polymer basis) Antiwear 0.01-1.2 0.01-1.sup. Corrosion Inhibitor
and 0.01-5 0.01-1.5 Antirust
[0105] The foregoing additives are all commercially available
materials. These additives may be added independently but are
usually precombined in packages which can be obtained from
suppliers of lubricant oil additives. Additive packages with a
variety of ingredients, proportions and characteristics are
available and selection of the appropriate package will take the
requisite use of the ultimate composition into account.
[0106] The method and lubricating composition of the disclosure may
be suitable hydraulic fluids, turbine oils, industrial fluids,
circulating oils, or combinations thereof. In different
embodiments, the lubricating composition is suitable for various
mechanical devices including industrial systems, hydraulic systems
or turbines. In one embodiment the lubricating composition is
suitable for a hydraulic system.
[0107] In some embodiments, the methods and compositions of the
disclosure are used in a hydraulic pump. In one embodiment, the
pump is a hydraulic piston pump. In one embodiment, the pump is a
vane pump. In another embodiment, the pump is a hydraulic hybrid
piston and vane pump. In other embodiments, the methods and
compositions of the disclosure are used in turbines.
[0108] In one set of embodiments, the hydraulic fluid and turbine
oil of the disclosure contain a Group III oil as described herein,
and an additive package containing a dispersant (optional), at
least one antioxidant, at least one antiwear additive (optional),
an antifoam agent, a corrosion inhibitor, and a metal deactivator.
Such additive packages may be present at any of the ranges
described above, or at 0.04 to 3 wt %.
[0109] While we have shown and described several embodiments in
accordance with our disclosure, it is to be clearly understood that
the same may be susceptible to numerous changes apparent to one
skilled in the art. Therefore, we do not wish to be limited to the
details shown and described but intend to show all changes and
modifications that come within the scope of the appended
claims.
EXAMPLES
[0110] Varnish deposits from oxidation byproducts of hydraulic
fluids in service severely impacts the performance of the hydraulic
system and can reduce the efficiency and productivity of the
lubricant end user. Varnish control of a hydraulic fluid is
assessed in a controlled hydraulic system operating at constant
temperature and pressure and the presence of metal catalysts and
water contamination by rating the cleanliness of the oil reservoir
of the system periodically. The time to failure is determined to be
the number of hours for the CRC rating of varnish on the reservoir
to reach 7.
[0111] The test rig used to evaluate the fluids was a typical
hydraulic circuit composed of a reservoir, hydraulic pump, relief
valve, heat exchanger, and filter element. The fluid temperature
was kept between 170.degree. F. and 180.degree. F. and exposed to
water, debris, airborne particulates, and metal catalyst.
Photographs of the reservoirs were taken periodically to determine
the extent of varnish according to the CRC rating scale.
[0112] Table 3 shows results from the testing. Improvement was
shown in varnish control of Shell QHVI base oil formulated
hydraulic oils over other Group I and Group III base oil
formulations.
TABLE-US-00003 TABLE 3 Time to Base Oil Failure Result Group I 1800
hours Group III 3375 hours Expected improvement versus Group I
(Yubase) Group III 4625 hours Unexpected improvement versus another
(Shell QHVI) Group III basestock
[0113] FIG. 1 shows photographs taken to determine the extent of
varnish deposit according to the CRC rating scale. The photographs
are of the bottom of the fluid reservoir after 3750 hours of
testing. The left reservoir contained a hydraulic fluid using API
Group III base oil, Shell QHVI. The right reservoir contained a
hydraulic fluid using API Group III base oil, Yubase. Both fluids
used the same additive chemistry.
[0114] A turbine oil formulation was evaluated in a similar pump
test as the hydraulic fluid above.
[0115] FIG. 2 shows photographs taken to determine the extent of
varnish deposit according to the CRC rating scale. The photographs
are of the bottom of the fluid reservoir after 2000 hours of
testing. The right reservoir contained a turbine oil using API
Group III base oil, Shell QHVI. The left reservoir contained a
turbine oil using API Group III base oil, Yubase. Both fluids used
the same additive chemistry. The CRC rating for varnish for the
turbine oil using API Group III base oil, Shell QHVI, was 9.3, and
the CRC rating for varnish for the turbine oil using API Group III
base oil, Yubase, was 7.6. For the turbine oil test, a 1-10 CRC
rating system was used with 10 being the cleanest. The results are
shown in Table 4.
TABLE-US-00004 TABLE 4 CRC Rating Base Oil @ 2000 hrs Result Group
III 7.6 (Yubase) Group III 9.3 Unexpected improvement versus
another (Shell QHVI) Group III basestock
PCT and EP Clauses:
[0116] 1. A method for improving varnish control in a mechanical
device requiring hydraulic fluids, turbine oils, industrial fluids,
circulating oils, or combinations thereof, said method
comprising:
[0117] supplying the mechanical device with a lubricating
composition comprising a Group III lubricating oil base stock;
[0118] wherein the Group III lubricating oil base stock has a
viscosity from 3.8 to 8.5 mm.sup.2/s at 100.degree. C., a viscosity
index greater than 120, a sulfur content less than 0.0003 weight
percent, and an aromatic hydrocarbon content less than 0.2 weight
percent, based on the total weight of the Group III lubricating oil
base stock; and
[0119] wherein varnish reduction properties are improved as
compared to varnish reduction properties achieved using a
lubricating composition containing a different Group III
lubricating oil base stock.
[0120] 2. The method of clause 1 wherein the Group III lubricating
oil base stock has a viscosity from 4.0 to 8.3 mm.sup.2/s at
100.degree. C., a viscosity index greater than 125, a sulfur
content less than 0.0002 weight percent, and an aromatic
hydrocarbon content less than 0.18 weight percent, based on the
total weight of the Group III lubricating oil base stock.
[0121] 3. The method of clauses 1 and 2 wherein the Group III
lubricating oil base stock contains consecutive carbon numbers, and
is a Gas-to-Liquids (GTL) oil base stock or a Fischer-Tropsch wax
derived oil base stock.
[0122] 4. The method of clauses 1-3 wherein the lubricating
composition further comprises (i) a Group II co-base stock; wherein
the Group II co-base stock has a viscosity from 6.5 to 11.0
mm.sup.2/s at 40.degree. C., is isoparaffinic, and is produced from
natural gas and subsequent wax isomerization; or (ii) a heavy Group
II base stock having a viscosity from 10.0 to 13.0 mm.sup.2/s at
100.degree. C., a viscosity index greater than 90, a sulfur content
less than 0.001 weight percent, and saturates content greater than
99%.
[0123] 5. The method of clauses 1-4 wherein the Group III
lubricating oil base stock is present in an amount from 80 weight
percent to 99 weight percent, based on the total weight of the
lubricating composition.
[0124] 6. The method of clauses 1-5 wherein the lubricating
composition further comprises at least one of an antiwear additive,
viscosity index improver, antioxidant, dispersant, pour point
depressant, corrosion inhibitor, metal deactivator, seal
compatibility additive, antifoam agent, co-base stock, pour point
depressant, seal compatibility additive, solubility improver, and
antirust additive.
[0125] 7. The method of clauses 1-6 wherein the mechanical device
is a hydraulic system or a turbine system.
[0126] 8. A lubricating composition comprising:
[0127] a Group III lubricating oil base stock, wherein the Group
III lubricating oil base stock has a viscosity from 3.8 to 8.5
mm.sup.2/s at 100.degree. C., a viscosity index greater than 120, a
sulfur content less than 0.0003 weight percent, and an aromatic
hydrocarbon content less than 0.2 weight percent, based on the
total weight of the Group III lubricating oil base stock; and
[0128] optionally one or more of an additive, viscosity index
improver, antioxidant, dispersant, pour point depressant, corrosion
inhibitor, metal deactivator, seal compatibility additive, antifoam
agent, co-base stock, pour point depressant, seal compatibility
additive, solubility improver, and antirust additive;
[0129] wherein, in a mechanical device supplied with the
lubricating composition, varnish reduction properties are improved
as compared to varnish reduction properties achieved using a
lubricating composition containing a different Group III
lubricating oil base stock.
[0130] 9. The lubricating composition of clause 8 which is a
hydraulic fluid, turbine oil, industrial fluid, circulating oil, or
combination thereof
[0131] 10. The lubricating composition of clauses 8 and 9 wherein
the Group III lubricating oil base stock has a viscosity from 4.0
to 8.3 mm.sup.2/s at 100.degree. C., a viscosity index greater than
125, a sulfur content less than 0.0002 weight percent, and an
aromatic hydrocarbon content less than 0.18 weight percent, based
on the total weight of the Group III lubricating oil base
stock.
[0132] 11. The lubricating composition of clauses 8-10 wherein the
Group III lubricating oil base stock contains consecutive carbon
numbers, and is a Gas-to-Liquids (GTL) oil base stock or a
Fischer-Tropsch wax derived oil base stock.
[0133] 12. The lubricating composition of clauses 8-11 wherein the
lubricating composition further comprises (i) a Group II co-base
stock; wherein the Group II co-base stock has a viscosity from 6.5
to 11.0 mm.sup.2/s at 40.degree. C., is isoparaffinic, and is
produced from natural gas and subsequent wax isomerization; or (ii)
a heavy Group II base stock having a viscosity from 10.0 to 13.0
mm.sup.2/s at 100.degree. C., a viscosity index greater than 90, a
sulfur content less than 0.001 weight percent, and saturates
content greater than 99%.
[0134] 13. The lubricating composition of clauses 8-12 wherein the
Group III lubricating oil base stock is present in an amount from
80 weight percent to 99 weight percent, based on the total weight
of the lubricating composition.
[0135] 14. The lubricating composition of clauses 8-13 wherein the
improved varnish reduction properties are rated according to a
Coordinating Research Council (CRC) rating scale, the sulfur
content is determined according to ASTM D2622, and the aromatic
hydrocarbon content is determined according to ASTM D7419.
[0136] 15. The lubricating composition of clauses 8-14 wherein the
mechanical device is a hydraulic system or a turbine system.
[0137] All patents and patent applications, test procedures (such
as ASTM methods, UL methods, and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this disclosure and for all
jurisdictions in which such incorporation is permitted.
[0138] When numerical lower limits and numerical upper limits are
listed herein, ranges from any lower limit to any upper limit are
contemplated. While the illustrative embodiments of the disclosure
have been described with particularity, it will be understood that
various other modifications will be apparent to and can be readily
made by those skilled in the art without departing from the spirit
and scope of the disclosure. Accordingly, it is not intended that
the scope of the claims appended hereto be limited to the examples
and descriptions set forth herein but rather that the claims be
construed as encompassing all the features of patentable novelty
which reside in the present disclosure, including all features
which would be treated as equivalents thereof by those skilled in
the art to which the disclosure pertains.
[0139] The present disclosure has been described above with
reference to numerous embodiments and specific examples. Many
variations will suggest themselves to those skilled in this art in
light of the above detailed description. All such obvious
variations are within the full intended scope of the appended
claims.
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References