U.S. patent application number 16/021108 was filed with the patent office on 2019-01-03 for marine diesel lubricant oil compositions.
The applicant listed for this patent is Chevron Oronite Company LLC, Chevron Oronite Technology B.V.. Invention is credited to Mia Gill, Wilhelmus Petrus Antonie van Houten.
Application Number | 20190002795 16/021108 |
Document ID | / |
Family ID | 63080220 |
Filed Date | 2019-01-03 |
![](/patent/app/20190002795/US20190002795A1-20190103-C00001.png)
United States Patent
Application |
20190002795 |
Kind Code |
A1 |
Gill; Mia ; et al. |
January 3, 2019 |
MARINE DIESEL LUBRICANT OIL COMPOSITIONS
Abstract
A lubricating oil composition is provided which comprises (a)
greater than 50 wt. % of a base oil of lubricating viscosity; and
(b) 0.1 to 40 wt. % of an overbased alkaline earth metal
alkyl-substituted hydroxyaromatic carboxylate, wherein the alkyl
substituent is a residue derived from an isomerized alpha-olefin
having from 12 to 40 carbon atoms, and having a TBN, on an actives
basis, of less than 600 mg KOH/g, as determined by ASTM D 2896;
wherein the lubricating oil composition is a monograde lubricating
oil composition meeting specifications for SAE J300 revised January
2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine
oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM
D2896.
Inventors: |
Gill; Mia; (Novato, CA)
; van Houten; Wilhelmus Petrus Antonie; (Prinsenbeek,
NL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chevron Oronite Company LLC
Chevron Oronite Technology B.V. |
San Ramon
San Ramon |
CA
CA |
US
US |
|
|
Family ID: |
63080220 |
Appl. No.: |
16/021108 |
Filed: |
June 28, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62527321 |
Jun 30, 2017 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2030/42 20200501;
C10M 119/02 20130101; C10M 129/56 20130101; C10M 135/10 20130101;
C10M 159/22 20130101; C10N 2040/253 20200501; C10N 2030/02
20130101; C10M 2203/1025 20130101; C10M 133/04 20130101; C10M
2215/26 20130101; C10M 2219/046 20130101; C10M 2205/026 20130101;
C10N 2030/04 20130101; C10M 169/06 20130101; C10M 2207/26 20130101;
C10M 129/50 20130101; C10M 2223/045 20130101; C10M 119/06 20130101;
C10M 141/10 20130101; C10N 2030/10 20130101; C10M 2215/28 20130101;
C10M 137/10 20130101; C10M 2207/028 20130101; C10N 2040/252
20200501; C10M 2219/044 20130101; C10M 129/64 20130101; C10M
2207/262 20130101; C10N 2030/52 20200501; C10M 2215/06 20130101;
C10M 2207/262 20130101; C10N 2010/04 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101; C10M 2207/028 20130101; C10N
2010/04 20130101; C10M 2207/262 20130101; C10N 2010/04 20130101;
C10M 2207/028 20130101; C10N 2010/04 20130101; C10M 2203/1025
20130101; C10N 2020/02 20130101 |
International
Class: |
C10M 169/06 20060101
C10M169/06; C10M 129/56 20060101 C10M129/56; C10M 129/50 20060101
C10M129/50; C10M 129/64 20060101 C10M129/64; C10M 135/10 20060101
C10M135/10; C10M 133/04 20060101 C10M133/04; C10M 137/10 20060101
C10M137/10; C10M 141/10 20060101 C10M141/10; C10M 119/02 20060101
C10M119/02; C10M 119/06 20060101 C10M119/06 |
Claims
1. A lubricating oil composition comprising (a) greater than 50 wt.
% of a base oil of lubricating viscosity; and (b) 0.1 to 40 wt. %
of an overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate, wherein the alkyl substituent is a
residue derived from an isomerized alpha-olefin having from 12 to
40 carbon atoms, and having from a TBN, on an actives basis, of
less than 600 mg KOH/g, as determined by ASTM D2896; wherein the
lubricating oil composition is a monograde lubricating oil
composition meeting specifications for SAE J300 revised January
2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine
oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM
D2896.
2. The lubricating oil composition of claim 1, wherein the alkyl
substituent of the overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate is a residue derived from an isomerized
alpha-olefin having from 14 to 28 carbon atoms per molecule.
3. The lubricating oil composition of claim 1, wherein the alkyl
substituent of the overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate is a residue derived from an isomerized
alpha-olefin having from 20 to 28 carbon atoms per molecule.
4. The lubricating oil composition of claim 1, wherein the alkyl
substituent of the overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate is a residue derived from an isomerized
alpha-olefin having from 20 to 24 carbon atoms per molecule.
5. The lubricating oil composition of claim 1, wherein the
alpha-olefin is a normal alpha-olefin.
6. The lubricating oil composition of claim 1, wherein the
overbased alkaline earth metal alkyl-substituted hydroxyaromatic
carboxylate has TBN, on an actives basis, of 100 to 590 mg
KOH/g.
7. The lubricating oil composition of claim 1, wherein the
lubricating oil composition has a TBN in one of the following
ranges: 5 to 10 mg KOH/g, 15 to 150 mg KOH/g, 20 to 80 mg KOH/g, 30
to 100 mg KOH/g, 30 to 80 mg KOH/g, 60 to 100 mg KOH/g, 60 to 150
mg KOH/g.
8. The lubricating oil composition of claim 1, further comprising
one or more of other detergents, a dispersant, an antiwear agent,
an antioxidant, a friction modifier, a corrosion inhibitor, a rust
inhibitor, a demulsifier, a foam inhibitor, a viscosity modifier, a
pour point depressant, a non-ionic surfactant, and a thickener.
9. A method of lubricating a compression-ignited internal
combustion engine comprising supplying to the compression-ignited
internal combustion engine the lubricating oil composition of claim
1.
10. The method of claim 9, wherein the compression-ignited internal
combustion engine is a 4-stroke engine operated at 250 to 1100
rpm.
11. The method of claim 9, wherein the compression-ignited internal
combustion engine is a 2-stroke engine operated at 200 rpm or
less.
12. The method of claim 9, wherein the compression-ignited engine
is fueled with a residual fuel, a marine residual fuel, a low
sulfur marine residual fuel, a marine distillate fuel, a low sulfur
marine distillate fuel, a gaseous fuel, a high sulfur fuel, or a
gaseous fuel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
Provisional Application Ser. No. 62/527,321, filed Jun. 30,
2017.
TECHNICAL FIELD
[0002] This disclosure relates to lubricating oil compositions that
contain an overbased alkaline-earth metal alkyl-substituted
hydroxyaromatic carboxylate detergent having a TBN, on an actives
basis, of less than 600 mg KOH/g.
BACKGROUND
[0003] Marine diesel internal combustion engines may generally be
classified as low-speed, medium-speed, or high-speed engines.
Low-speed diesel engines are unique in size and method of
operation. These engines are quite large and typically operate in
the range of about 60 to 200 revolutions per minute (rpm). A
low-speed diesel engine operates on the two-stroke cycle and is
typically a direct-coupled and direct-reversing engine of
"crosshead" construction, with a diaphragm and one or more stuffing
boxes separating the power cylinders from the crankcase to prevent
combustion products from entering the crankcase and mixing with the
crankcase oil. Marine two-stroke diesel cylinder lubricants must
meet performance demands in order to comply with severe operating
conditions required for more modern larger bore engines which are
run at significantly varying outputs, loads and temperatures of the
cylinder liner. The complete separation of the crankcase from the
combustion zone has led persons skilled in the art to lubricate the
combustion chamber and the crankcase with different lubricating
oils, a cylinder lubricant and a system oil respectively, due to
the unique requirements of each type of lubricant.
[0004] In two-stroke crosshead engines, the cylinders are
lubricated on a total loss basis with the cylinder oil being
injected separately on each cylinder, by means of lubricators
positioned around the cylinder liner. Cylinder lubricant is not
recirculated and is combusted along with the fuel. The cylinder
lubricant needs to provide a strong film between the cylinder liner
and the piston rings for sufficient lubrication of the cylinder
walls to prevent scuffing, be thermally stable in order that the
lubricant does not form deposits on the hot surfaces of the piston
and the piston rings, and be able to neutralize sulfur-based acidic
products of combustion.
[0005] The system oil lubricates the crankshaft and the crosshead
of a two-stroke engine. It lubricates the main bearings, the
crosshead bearings, gears and the camshaft and it cools the piston
undercrown and protects the crankcase against corrosion. A system
oil needs to be able to prevent corrosion of metal in the bearing
shells and to prevent rust in the crankcase when in the presence of
contaminated water. The system oil also needs to provide adequate
hydrodynamic lubrication of the bearings and have an anti-wear
system sufficient to provide wear protection to the bearings and
gears under extreme pressure conditions. In contrast to a cylinder
lubricant, system oil is not exposed to the combustion chamber
where fuels are being combusted and is formulated to last as long
as possible to maximize the lifetime of the oil. Therefore, the
primary performance characteristics of system oils are related to
wear protection, oxidative stability, viscosity increase control
and deposit performance.
[0006] Medium-speed engines, typically operate in the range of
about 250 to 1100 rpm and operate on the four-stroke cycle. These
engines are typically of the trunk piston design. In trunk piston
engines, a single lubricating oil is employed for lubrication of
all areas of the engine, as opposed to the crosshead engines. A
trunk piston engine oil therefore has unique requirements. Key
performance parameters for operating trunk piston engines include:
deposit control of the piston cooling gallery and piston ring pack,
oxidation and viscosity increase control, demulsibility performance
and sludge control. For marine residual fuels operation, these
performance parameters are almost exclusively driven by asphaltenes
contamination from marine residual fuels.
[0007] Recent health and environmental concerns, have led to
regulations mandating the use of low sulfur fuels for the operation
of marine diesel engines. As a result, manufacturers are now
designing marine diesel engines for use with a variety of fuels
including non-residual gaseous fuels (e.g., compressed or liquefied
natural gas) and high quality distillate fuel, to poorer quality
intermediate or heavy fuel such as marine residual fuel with
generally higher sulfur and higher asphaltene content. For
non-residual fuel operation, the fuel contains no significant
asphaltenes present in the fuels and contains much lower sulfur
levels. When the lower sulfur fuel is combusted, less acid is
formed in the combustion chamber. The requirements for lubricants
used for the operation of engines using low sulfur gaseous and
distillate fuels versus marine residual fuels are very
different.
[0008] In view of restrictive emissions regulations, and changing
fuel sources and operating conditions for marine diesel internal
combustion engines, there is continuing need for improved marine
diesel lubricating oil additive technology.
SUMMARY
[0009] In one aspect, there is provided a lubricating oil
composition comprising (a) greater than 50 wt. % of a base oil of
lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased
alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate,
wherein the alkyl substituent is a residue derived from an
isomerized alpha-olefin having from 12 to 40 carbon atoms, and
having a TBN, on an actives basis, of less than 600 mg KOH/g, as
determined by ASTM D 2896; wherein the lubricating oil composition
is a monograde lubricating oil composition meeting specifications
for SAE J300 revised January 2015 requirements for a SAE 20, 30,
40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg
KOH/g, as determined by ASTM D2896.
[0010] In another aspect, there is provided a method of lubricating
a compression-ignited internal combustion engine comprising
supplying to the compression-ignited internal combustion engine the
lubricating oil composition disclosed herein.
[0011] In yet another aspect, there is provided a lubricating oil
composition comprising (a) greater than 50 wt. % of a base oil of
lubricating viscosity; and (b) 0.1 to 40 wt. % of an overbased
alkaline earth metal alkyl-substituted hydroxyaromatic carboxylate,
wherein the alkyl substituent is a residue derived from an
isomerized alpha-olefin having from 12 to 40 carbon atoms, and
having a TBN, on an actives basis, of less than 600 mg KOH/g, as
determined by ASTM D 2896; wherein the lubricating oil composition
is a monograde lubricating oil composition meeting specifications
for SAE J300 revised January 2015 requirements for a SAE 20, 30,
40, 50, or 60 monograde engine oil, and has a TBN of 5 to 200 mg
KOH/g, as determined by ASTM D2896, which improves low temperature
performance of the lubricant and additionally improves black sludge
deposit performance, asphaltene dispersancy, BN retention, and
oxidation performance.
DETAILED DESCRIPTION
Introduction
[0012] In this specification, the following words and expressions,
if and when used, have the meanings ascribed below.
[0013] A "major amount" means greater than 50 wt. % of a
composition.
[0014] A "minor amount" means less than 50 wt. % of a
composition.
[0015] An "alpha-olefin" as used in this specification and claims
refers to an olefin that has a carbon-carbon double bond between
the first and second carbon atoms of the longest contiguous chain
of carbon atoms. The term "alpha-olefin" includes linear and
branched alpha olefins unless expressly stated otherwise. In the
case of branched alpha olefins, a branch can be at the 2-position
(a vinylidene) and/or the 3-position or higher with respect to the
olefin double bond. The term "vinylidene" whenever used in this
specification and claims refers to an alpha olefin having a branch
at the 2-position with respect to the olefin double bond.
Alpha-olefins are almost always mixtures of isomers and often also
mixtures of compounds with a range of carbon numbers. Low molecular
weight alpha olefins, such as the C.sub.6, C.sub.8, C.sub.10,
C.sub.12 and C.sub.14 alpha olefins, are almost exclusively
1-olefins. Higher molecular weight olefin cuts such as
C.sub.16-C.sub.18 or C.sub.20-C.sub.24 have increasing proportions
of the double bond isomerized to an internal or vinylidene
position
[0016] A "normal alpha olefin" (NAO) refers to a linear aliphatic
mono-olefin having a carbon-carbon double bond between the first
and second carbon atoms. It is noted that "normal alpha olefin" is
not synonymous with "linear alpha olefin" as the term "linear alpha
olefin" can include linear olefinic compounds having a double bond
between the first and second carbon atoms.
[0017] "Isomerized olefins" or "isomerized normal alpha-olefins"
refers to olefins obtained by isomerizing olefins. Generally
isomerized olefins have double bonds in different positions than
the starting olefins from which they are derived, and may also have
different characteristics.
[0018] "TBN" means total base number as measured by ASTM D2896.
[0019] "KV.sub.100" means kinematic viscosity at 100.degree. C. as
measured by ASTM D445.
[0020] "Pour point" is the temperature at which a sample will begin
to flow under carefully controlled conditions. The pour points
referred to herein were determined according to ASTM D6749.
[0021] "Basicity Index" is the molar ratio of total base to total
soap in an overbased detergent.
[0022] "Overbased" is used to describe metal detergents in which
the ratio of the number of equivalents of the metal moiety to the
number of equivalents of the acid moiety is greater than one.
[0023] "Soap" means a neutral detergent compound that contains
approximately the stoichiometric amount of metal to achieve the
neutralization of the acidic group or groups present in the organic
acid used to make the detergent.
[0024] ""Metal" refers to alkali metals, alkaline earth metals, or
mixtures thereof. When an alkali metal is employed, the alkali
metal is lithium, sodium or potassium. When an alkaline earth metal
is employed, the alkaline earth metal can be selected from the
group consisting of calcium, barium, magnesium and strontium.
Calcium and magnesium are preferred.
[0025] "Weight percent" (wt. %), unless expressly stated otherwise,
means the percentage that the recited component(s), compounds(s) or
substituent(s) represents of the total weight of the entire
composition.
[0026] All percentages reported are weight % on an active
ingredient basis (i.e., without regard to carrier or diluent oil)
unless otherwise stated. The diluent oil for the lubricating oil
additives can be any suitable base oil (e.g., a Group I base oil, a
Group II base oil, a Group III base oil, a Group IV base oil, a
Group V base oil, or a mixture thereof).
Lubricating Oil Composition
[0027] The lubricating oil composition of the present disclosure
comprises (a) greater than 50 wt. % of a base oil of lubricating
viscosity; and (b) 0.1 to 40 wt. % of an overbased alkaline earth
metal salt of an alkyl-substituted hydroxyaromatic compound, the
alkyl substituent being a residue derived from an isomerized
alpha-olefin having from 12 to 40 carbon atoms per molecule;
wherein the lubricating oil composition is a monograde lubricating
oil composition meeting specifications for SAE J300 revised January
2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine
oil, and has a TBN of 5 to 200 mg KOH/g, as determined by ASTM
D2896.
[0028] The lubricating oil composition is monograde lubricating oil
composition meeting specifications for SAE J300 revised January
2015 requirements for a SAE 20, 30, 40, 50, or 60 monograde engine
oil. A SAE 20 oil has a kinematic viscosity at 100.degree. C. of
6.9 to <9.3 mm.sup.2/s. A SAE 30 oil has a kinematic viscosity
at 100.degree. C. of 9.3 to <12.5 mm.sup.2/s. A SAE 40 oil has a
kinematic viscosity at 100.degree. C. of 12.5 to <16.3
mm.sup.2/s. A SAE 50 oil has a kinematic viscosity at 100.degree.
C. of 16.3 to <21.9 mm.sup.2/s. A SAE 60 oil has a kinematic
viscosity at 100.degree. C. of 21.9 to <26.1 mm.sup.2/s.
[0029] In some embodiments, the lubricating oil composition is
suitable for use as a marine cylinder lubricant (MCL). Marine
cylinder lubricants are typically made to the SAE 30, SAE 40, SAE
50 or SAE 60 monograde specification in order to provide a
sufficiently thick lubricant film at the high temperatures on the
cylinder liner wall. Typically, marine diesel cylinder lubricants
have a TBN ranging from 15 to 200 mg KOH/g (e.g., from 15 to 150 mg
KOH/g, from 15 to 60 mg KOH/g, from 20 to 200 mg KOH/g, from 20 to
150 mg KOH/g from 20 to 120 mg KOH/g, from 20 to 80 mg KOH/g, from
30 to 200 mg KOH/g, or from 30 to 150 mg KOH/g, or from 30 to 120
mg KOH/g, from 30 to 100 mg KOH/g, from 30 to 80 mg KOH/g, from 60
to 200 mg KOH/g, from 60 to 150 mg KOH/g, from 60 to 120 mg KOH/g,
from 60 to 100 mg KOH/g, from 60 to 80 mg KOH/g, from 80 to 200 mg
KOH/g, from 80 to 150 mg KOH/g, from 80 to 150 mg 120 KOH/g, from
120 to 200 mg KOH/g, or from 120 to 150 mg KOH/g).
[0030] In some embodiments, the present lubricating oil composition
is suitable for use as a marine system oil. Marine system oil
lubricants are typically made to the SAE 20, SAE 30 or SAE 40
monograde specification. The viscosity for the marine system oil is
set at such a relatively low level in part because a system oil can
increase in viscosity during use and the engine designers have set
viscosity increase limits to prevent operational problems.
Typically, marine system oil lubricants have a TBN ranging from 5
to 12 mg KOH/g (e.g., from 5 to 10 mg KOH/g or from 5 to 9 mg
KOH/g).
[0031] In some embodiments, the present lubricating oil composition
is suitable for use as a marine trunk piston engine oil (TPEO).
Marine TPEO lubricants are typically made to the SAE 30 or SAE 40
monograde specification. Typically, marine TPEO lubricants have a
TBN ranging from 10 to 60 mg KOH/g (e.g., from 10 to 30 mg KOH/g,
from 20 to 60 mg KOH/g, 20 to 40 mg KOH/g, from 30 to 60 mg KOH/g,
or from 30 to 55 mg KOH/g).
Oil of Lubricating Viscosity
[0032] The oil of lubricating viscosity may be selected from any of
the base oils in Groups I-V as specified in the American Petroleum
Institute (API) Base Oil Interchangeability Guidelines (API 1509).
The five base oil groups are summarized in Table 1:
TABLE-US-00001 TABLE 1 Group Saturates.sup.(1) Sulfur.sup.(2)
Viscosity Index.sup.(3) I <90% and/or >0.03% and .gtoreq.80
to <120 II .gtoreq.90% and .ltoreq.0.03% and .gtoreq.80 to
<120 III .gtoreq.90% and .ltoreq.0.03% and .gtoreq.120 IV
Polyalphaolefins (PAO) V All other base stocks not included in
Groups I, II, III or IV .sup.(1)ASTM D2007 .sup.(2)ASTM D2270
.sup.(3)ASTM D3120, ASTM D4294, or ASTM D4297
[0033] Groups I, II, and III are mineral oil process stocks. Group
IV base oils contain true synthetic molecular species, which are
produced by polymerization of olefinically unsaturated
hydrocarbons. Many Group V base oils are also true synthetic
products and may include diesters, polyol esters, polyalkylene
glycols, alkylated aromatics, polyphosphate esters, polyvinyl
ethers, and/or polyphenyl ethers, and the like, but may also be
naturally occurring oils, such as vegetable oils. It should be
noted that although Group III base oils are derived from mineral
oil, the rigorous processing that these fluids undergo causes their
physical properties to be very similar to some true synthetics,
such as PAOs. Therefore, oils derived from Group III base oils may
be referred to as synthetic fluids in the industry.
[0034] The base oil used in the disclosed lubricating oil
composition may be a mineral oil, animal oil, vegetable oil,
synthetic oil, or mixtures thereof. Suitable oils may be derived
from hydrocracking, hydrogenation, hydrofinishing, unrefined,
refined, and re-refined oils, and mixtures thereof.
[0035] Unrefined oils are those derived from a natural, mineral, or
synthetic source without or with little further purification
treatment. Refined oils are similar to the unrefined oils except
that they have been treated in one or more purification steps,
which may result in the improvement of one or more properties.
Examples of suitable purification techniques are solvent
extraction, secondary distillation, acid or base extraction,
filtration, percolation, and the like. Oils refined to the quality
of an edible may or may not be useful. Edible oils may also be
called white oils. In some embodiments, lubricating oil
compositions are free of edible or white oils.
[0036] Re-refined oils are also known as reclaimed or reprocessed
oils. These oils are obtained similarly to refined oils using the
same or similar processes. Often these oils are additionally
processed by techniques directed to removal of spent additives and
oil breakdown products.
[0037] Mineral oils may include oils obtained by drilling or from
plants and animals or any mixtures thereof. Such oils may include
castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil,
and linseed oil, as well as mineral lubricating oils, such as
liquid petroleum oils and solvent-treated or acid-treated mineral
lubricating oils of the paraffinic, naphthenic or mixed
paraffinic-naphthenic types. Such oils may be partially or fully
hydrogenated, if desired. Oils derived from coal or shale may also
be useful.
[0038] Useful synthetic lubricating oils may include hydrocarbon
oils such as polymerized, oligomerized, or interpolymerized olefins
(e.g., polybutylenes, polypropylenes, propylene/isobutylene
copolymers); poly(1-hexenes), poly(1-octenes), trimers or oligomers
of 1-decene, e.g., poly(1-decenes), such materials being often
referred to as .alpha.-olefins, and mixtures thereof; alkylbenzenes
(e.g. dodecyl benzenes, tetradecylbenzenes, dinonylbenzenes,
di-(2-ethylhexyl)-benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenyls); diphenyl alkanes, alkylated
diphenyl alkanes, alkylated diphenyl ethers and alkylated diphenyl
sulfides and the derivatives, analogs and homologs thereof or
mixtures thereof. Polyalphaolefins are typically hydrogenated
materials.
[0039] Other synthetic lubricating oils include polyol esters,
diesters, liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, and the diethyl ester of
decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic
oils may be produced by Fischer-Tropsch reactions and typically may
be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one
embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid
synthetic procedure as well as other gas-to-liquid oils.
[0040] Base oils for use in the formulated lubricating oils useful
in 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. In one embodiment, the base oil
is a Group II base oil or a blend of two or more different base
oils. In another embodiment, the base oil is a Group I base oil or
a blend of two or more different Group I base oils. Suitable Group
I base oils include any light overhead cuts from a vacuum
distillation column, such as, for example, any Light Neutral,
Medium Neutral, and Heavy Neutral base stocks. The base oil may
also include residual base stocks or bottoms fractions such as
bright stock. Bright stock is a high viscosity base oil which has
been conventionally produced from residual stocks or bottoms and
has been highly refined and dewaxed. Bright stock can have a
kinematic viscosity at 40.degree. C. of greater than 180 mm.sup.2/s
(e.g., greater than 250 mm.sup.2/s, or even in a range of 500 to
1100 mm.sup.2/s).
[0041] The base oil constitutes the major component of the
lubricating oil composition of the present disclosure and is
present in an amount greater than 50 wt. % (e.g., at least 60 wt.
%, at least 70 wt. %, at least 80 wt. %, or at least 90 wt. %),
based on the total weight of the composition. The base oil
conveniently has a kinematic viscosity of 2 to 40 mm.sup.2/s, as
measured at 100.degree. C.
Overbased Alkaline Earth Metal Alkyl-Substituted Hydroxyaromatic
Carboxylate Detergent
[0042] The overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate of the present disclosure has a TBN, on
an actives basis, of less than 600 mg KOH/g (e.g., 100 to 590 mg
KOH/g, 100 to 500 mg KOH/g, 100 to 450 mg KOH/g, or 100 to 400 mg
KOH/g, 100 to 350 mg KOH/g, 100 to 300 mg KOH/g, 150 to 590 mg
KOH/g, 150 to 500 mg KOH/g, 150 to 450 mg KOH/g, 150 to 400 mg
KOH/g, 150 to 350 mg KOH/g, 150 to 300 mg KOH/g, 200 to 590 mg
KOH/g, 200 to 500 mg KOH/g, 200 to 450 mg KOH/g, 200 to 400 mg
KOH/g, 200 to 350 mg KOH/g, 200 to 300 mg KOH/g).
[0043] The overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate of the present disclosure can have a
basicity index of greater than 1 to less than 9 (e.g., greater than
1 to less than 5).
[0044] In one embodiment, the overbased alkaline earth metal
alkyl-substituted hydroxyaromatic carboxylate detergent of the
present of disclosure is an overbased alkaline earth metal
alkyl-substituted hydroxybenzoate which contains a single type of
anion as a surfactant for the additive, for example, a member or
members of the alkyl salicylate group, and does not contain a
member or members of the sulfonate group, or a member of members of
the phenate group, other than phenate that is derived from inherent
phenol which is a result of the process to manufacture
salicylate.
[0045] In one embodiment, the overbased alkaline earth metal
alkyl-substituted hydroxyaromatic carboxylate detergent is not a
complex, or hybrid, detergent which is known in the art as
comprising a surfactant system derived from at least two
surfactants described above.
[0046] The overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate of the present disclosure will be
present in the lubricating oil composition in a minor amount
compared to the oil of lubricating viscosity. Generally, this
component is present in an amount of from 0.1 to 40 wt. % (0.1 to
30 wt. %, 0.1 to 25 wt. %, 0.1 to 20 wt. %, 0.1 to 15 wt. %, 0.1 to
10 wt. %, 0.5 to 40 wt. %, 0.5 to 30 wt. %, 0.5 to 25 wt. %, 0.5 to
20 wt. %, 0.5 to 15 wt. %, 0.5 to 10 wt. %, 1.0 to 40 wt. %, 1.0 to
30 wt. %, 1.0 to 25 wt. %, 1.0 to 20 wt. %, 1.0 to 15 wt. % 1.0 to
10 wt. %, 2.0 to 40 wt. %, 2.0 to 30 wt. %, 2.0 to 25 wt. %, 2.0 to
20 wt. %, 2.0 to 10 wt. %, 2.0 to 40 wt. %, 2.0 to 30 wt. %. 2.0 to
25 wt. %, 2.0 to 20 wt. %, 2.0 to 15 wt. %, 2.0 to 10 wt. %, 2.0 to
8 wt. %, 3.0 to 40 wt. %, 3.0 to 30 wt. %, 3.0 to 25 wt. %, 3.0 to
20 wt. %, 3.0 to 15 wt. %, 3.0 to 10 wt. %, 5.0 to 40 wt. %, 5.0 to
30 wt. %, 5.0 to 25 wt. %, 5.0 to 20 wt. %, 5.0 to 15 wt. %, or 5.0
to 10 wt. %) based on the total weight of the lubricating oil
composition.
[0047] In one embodiment, the alkaline earth metal
alkyl-substituted hydroxyaromatic carboxylate can be represented by
the following structure (1):
##STR00001##
wherein (i) M independently represents an alkaline earth metal
(e.g., Ba, Ca, and Mg) (ii) each carboxylate group independently
may be in the ortho, meta, or para position, or mixtures thereof,
relative to the hydroxyl group; and (iii) each of R.sup.1 and
R.sup.2 is independently an alkyl substituent having from 12 to 40
carbon atoms (e.g., 14 to 28 carbon atoms, 14 to 18 carbon atoms,
18 to 30 carbon atoms, 20 to 28 carbon atoms, or 20 to 24 carbon
atoms).
[0048] The alkyl substituent of the overbased alkaline earth metal
alkyl-substituted hydroxyaromatic carboxylate may be a residue
derived from an alpha-olefin having from 12 to 40 carbon atoms. In
one embodiment, the alkyl substituent is a residue derived from an
alpha-olefin having from 14 to 28 carbon atoms per molecule. In one
embodiment, the alkyl substituent is a residue derived from an
alpha-olefin having from 14 to 18 carbon atoms per molecule. In one
embodiment, the alkyl substituent is a residue derived from an
alpha-olefin having from 20 to 28 carbon atoms per molecule. In one
embodiment, the alkyl substituent is a residue derived from an
alpha-olefin having from 20 to 24 carbon atoms per molecule. In one
embodiment, the alkyl substituent is a residue derived from an
olefin comprising C.sub.12 to C.sub.40 oligomers of a monomer
selected from propylene, butylene, or mixtures thereof. Examples of
such olefins include propylene tetramer, butylene trimer,
isobutylene oligomers, and the like. The olefins employed may be
linear, isomerized linear, branched or partially branched linear.
The olefin may be a mixture of linear olefins, a mixture of
isomerized linear olefins, a mixture of branched olefins, a mixture
of partially branched linear or a mixture of any of the foregoing.
The alpha-olefin may be a normal alpha-olefin, an isomerized normal
alpha-olefin, or a mixture thereof.
[0049] In one embodiment where the alkyl substituent is a residue
derived from an isomerized alpha-olefin, the alpha-olefin can have
an isomerization level (I) of 0.1 to 0.4 (e.g., 0.1 to 0.3, or 0.1
to 0.2). The isomerization level (I) can be determined by .sup.1H
NMR spectroscopy and represents the relative amount of methyl
groups (--CH.sub.3) (chemical shift 0.30-1.01 ppm) attached to the
methylene backbone groups (--CH.sub.2--) (chemical shift 1.01-1.38
ppm) and is defined by the following formula:
I=m/(m+n)
where m is the .sup.1H NMR integral for methyl groups with chemical
shifts between 0.30.+-.0.03 to 1.01.+-.0.03 ppm, and n is the
.sup.1H NMR integral for methylene groups with chemical shifts
between 1.01.+-.0.03 to 1.38.+-.0.10 ppm.
[0050] Overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylates may be prepared by methods known in
the art, such as described, for example, in U.S. Pat. Nos.
8,030,258 and 8,993,499.
Process for Preparing the Overbased Alkaline Earth Metal
Alkyl-Substituted Hydroxyaromatic Carboxylate
[0051] The overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate of this disclosure can be prepared by
any process known to one skilled in the art for making
alkyl-substituted hydroxycarboxylic acids. For example, a process
for preparing an overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate can comprise (a) alkylating a
hydroxyaromatic compound with an olefin to produce an
alkyl-substituted hydroxyaromatic compound; (b) neutralizing the
alkyl-substituted hydroxyaromatic compound with an alkali metal
base to produce an alkali metal salt of an alkyl-substituted
hydroxyaromatic compound; (c) carboxylating the alkali metal salt
of an alkyl-substituted hydroxyaromatic compound with a
carboxylating agent (e.g., CO.sub.2) to produce an alkali metal
alkyl-substituted hydroxyaromatic carboxylate; (d) acidifying the
alkali metal alkyl-substituted hydroxyaromatic carboxylate with an
aqueous solution of an acid strong enough to produce an
alkyl-substituted hydroxyaromatic carboxylic acid; and (e)
overbasing alkaline earth metal alkyl-substituted hydroxyaromatic
carboxylate with a molar excess of alkaline earth metal base and at
least one acidic overbasing material.
[0052] (A) Alkylation
[0053] The alkylation is carried out by charging a hydrocarbon feed
comprising a hydroxyaromatic compound or a mixture of
hydroxyaromatic compounds, an olefin or a mixture of olefins, and
an acid catalyst to a reaction zone in which agitation is
maintained. The resulting mixture is held in the alkylation zone
under alkylation conditions for a time sufficient to allow
substantial conversion (e.g., at least 70% mole % of the olefin has
reacted) of the olefin to the hydroxyaromatic alkylate. After the
desired reaction time, the reaction mixture is removed from the
alkylation zone and fed to a liquid-liquid separator to allow
hydrocarbon products to separate from the acid catalyst which may
be recycled to the reactor in a closed loop. The hydrocarbon
product may be further treated to remove excess unreacted
hydroxyaromatic compounds and olefinic compounds from the desired
alkylate product. The excess hydroxyaromatic compounds can also be
recycled to the reactor.
[0054] Suitable hydroxyaromatic compounds include monocyclic
hydroxyaromatic compounds and polycyclic hydroxyaromatics
containing one or more aromatic moieties, such as one or more
benzene rings, optionally fused together or otherwise connected via
alkylene bridges. Exemplary hydroxyaromatic compounds include
phenol, cresol, and naphthol. In one embodiment, the
hydroxyaromatic compound is phenol.
[0055] The olefins employed may be linear, isomerized linear,
branched or partially branched linear. The olefin may be a mixture
of linear olefins, a mixture of isomerized linear olefins, a
mixture of branched olefins, a mixture of partially branched linear
or a mixture of any of the foregoing. In some embodiments, the
olefin is a normal alpha-olefin, an isomerized normal alpha-olefin,
or a mixture thereof.
[0056] In some embodiments, the olefin is a mixture of normal
alpha-olefins selected from olefins having from 12 to 40 carbon
atoms per molecule (e.g., 14 to 28 carbon atoms per molecule, 14 to
18 carbon atoms per molecule, 18 to 30 carbon atoms per molecule,
20 to 28 carbon atoms per molecule, 20 to 24 carbon atoms per
molecule) In some embodiments, the normal alpha-olefins are
isomerized using at least one of a solid or liquid catalyst.
[0057] In another embodiment, the olefins include one or more
olefins comprising C.sub.12 to C.sub.40 oligomers of monomers
selected from propylene, butylene or mixtures thereof. Generally,
the one or more olefins will contain a major mount of the C.sub.12
to C.sub.40 oligomers of monomers selected from propylene, butylene
or mixtures thereof. Examples of such olefins include propylene
tetramer, butylene trimer and the like. As one skilled in the art
will readily appreciate, other olefins may be present. For example,
the other olefins that can be used in addition to the C.sub.12 to
C.sub.40 oligomers include linear olefins, cyclic olefins, branched
olefins other than propylene oligomers such as butylene or
isobutylene oligomers, arylalkylenes and the like and mixtures
thereof. Suitable linear olefins include 1-hexene, 1-nonene,
1-decene, 1-dodecene and the like and mixtures thereof. Especially
suitable linear olefins are high molecular weight normal
alpha-olefins such as C.sub.16 to C.sub.30 normal alpha-olefins,
which can be obtained from processes such as ethylene
oligomerization or wax cracking. Suitable cyclic olefins include
cyclohexene, cyclopentene, cyclooctene and the like and mixtures
thereof. Suitable branched olefins include butylene dimer or trimer
or higher molecular weight isobutylene oligomers, and the like and
mixtures thereof. Suitable arylalkylenes include styrene, methyl
styrene, 3-phenylpropene, 2-phenyl-2-butene and the like and
mixtures thereof.
[0058] Any suitable reactor configuration may be used for the
reactor zone. These include batch and continuously stirred tank
reactors, reactor riser configurations, and ebullating or fixed bed
reactors.
[0059] The alkylation can be carried out at a temperature of from
15.degree. C. to 200.degree. C. and at a sufficient pressure that a
substantial portion of the feed components remain in the liquid
phase. Typically, a pressure of 0 to 150 psig is satisfactory to
maintain feed and products in the liquid phase.
[0060] The residence time in the reactor is a time that is
sufficient to convert a substantial portion of the olefin to
alkylate product. The time required may be from 30 seconds to about
300 minutes. A more precise residence time may be determined by
those skilled in the art using batch stirred reactors to measure
the kinetics of the alkylation process.
[0061] The at least one hydroxyaromatic compound or mixture of
hydroxyaromatic compounds and the mixture of olefins may be
injected separately into the reaction zone or may be mixed prior to
injection. Both single and multiple reaction zones may be used with
the injection of the hydroxyaromatic compounds and the olefins into
one, several, or all reaction zones. The reaction zones need not be
maintained at the same process conditions.
[0062] The hydrocarbon feed for the alkylation process may comprise
a mixture of hydroxyaromatic compounds and a mixture of olefins in
which the molar ratio of hydroxyaromatic compounds to olefins is
from 0.5:1 to 50:1 or more. In the case where the molar ratio of
hydroxyaromatic compounds to olefins is greater than 1:1, there is
an excess of hydroxyaromatic compounds present. Preferably, an
excess of hydroxyaromatic compounds is used to increase reaction
rate and improve product selectivity. When excess hydroxyaromatic
compounds are used, the excess unreacted hydroxyaromatic compounds
in the reactor effluent can be separated (e.g., by distillation)
and recycled to the reactor.
[0063] Typically, the alkyl-substituted hydroxyaromatic compound
comprises a mixture of mono alkyl-substituted isomers. The alkyl
group of the alkyl-substituted hydroxyaromatic compound is
typically attached to the hydroxyaromatic compound primarily in the
ortho and para positions, relative to the hydroxyl group. In one
embodiment, the alkylation product may contain 1 to 99% ortho
isomer and 99 to 1% para isomer. In another embodiment, the
alkylation product may contain 5 to 70% ortho and 95 to 30% para
isomer.
[0064] The acidic alkylation catalyst is a strong acid catalyst
such as a Bronsted or a Lewis acid. Useful strong acid catalysts
include hydrofluoric acid, hydrochloric acid, hydrobromic acid,
perchloric acid, nitric acid, sulfuric acid, trifluoromethane
sulfonic acid, fluorosulfonic acid, AMBERLYST.RTM. 36 sulfonic acid
(available from The Dow Chemical Company), nitric acid, aluminum
trichloride, aluminum tribromide, boron trifluoride, antimony
pentachloride, and the like and mixtures thereof. Acidic ionic
liquids can be used as an alternative to the commonly used strong
acid catalysts in alkylation processes.
[0065] (B) Neutralization
[0066] The alkyl-substituted hydroxyaromatic compound is
neutralized with an alkali metal base (e.g., oxide or hydroxides of
lithium, sodium or potassium). Neutralization may take place in the
presence of a light solvent (e.g., toluene, xylene isomers, light
alkylbenzene, and the like) to form an alkali metal salt of the
alkyl-substituted hydroxyaromatic compound. In one embodiment, the
solvent forms an azeotrope with water. In another embodiment, the
solvent may be a mono-alcohol such as 2-ethylhexanol. In this case,
the 2-ethylhexanol is eliminated by distillation before
carboxylation. The objective with the introduction of a solvent is
to facilitate the elimination of water.
[0067] The neutralization is carried out a temperature high enough
to eliminate water. The neutralization may be conducted under a
slight vacuum in order to require a lower reaction temperature.
[0068] In one embodiment, xylene is used as a solvent and the
reaction conducted at a temperature of 130.degree. C. to
155.degree. C. under an absolute pressure about 80 kPa.
[0069] In another embodiment, 2-ethylhexanol is used as a solvent.
As the boiling point of 2-ethylhexanol (184.degree. C.) is
significantly higher than xylene (140.degree. C.), the
neutralization is conducted at a temperature of at least
150.degree. C.
[0070] The pressure may be reduced gradually below atmospheric
pressure in order to complete the distillation of water. In one
embodiment, the pressure is reduced to no more 7 kPa.
[0071] By providing that operations are carried out at a
sufficiently high temperature and that the pressure in the reactor
is reduced gradually below atmospheric, the formation of the alkali
metal salt of an alkyl-substituted hydroxyaromatic compound is
carried out without the need to add a solvent and forms an
azeotrope with the water formed during this reaction. For instance,
the temperature is ramped up to 200.degree. C. and then the
pressure is gradually reduced below atmospheric. Preferably, the
pressure is reduced to no more than 7 kPa.
[0072] Elimination of water may occur over a period of at least 1
hour (e.g., at least 3 hours).
[0073] The quantities of reagent may correspond to the following: a
molar ratio of alkali metal base to alkyl-substituted
hydroxaromatic compound of from 0.5: to 1.2:1 (e.g., 0.9:1 to
1.05:1); and a wt./wt. ratio of solvent to alkyl-substituted
hydroxyaromatic compound of from 0.1:1 to 5:1 (e.g., 0.3:1 to
3:1).
[0074] (C) Carboxylation
[0075] The carboxylation step is conducted by simply bubbling
carbon dioxide (CO.sub.2) into the reaction medium originating from
the preceding neutralization step and is conducted until at least
50 mole % of the starting alkali metal salt of an alkyl-substituted
hydroxyaromatic compound is converted to an alkali metal
alkyl-substituted hydroxyaromatic carboxylate (measured as
hydroxybenzoic acid by potentiometric determination).
[0076] At least 50 mole % (e.g., at least 75 mole %, or even at
least 85 mole %) of the starting the alkali metal salt of an
alkyl-substituted hydroxyaromatic compound is converted to an
alkali metal alkyl-substituted hydroxyaromatic carboxylate using
CO.sub.2 at a temperature from 110.degree. C. to 200.degree. C.
under a pressure of from 0.1 to 1.5 MPa, for a period between 1 and
8 hours.
[0077] In one variant with a potassium salt, the temperature may be
from 125.degree. C. to 165.degree. C. (e.g., 130.degree. C. to
155.degree. C.) and the pressure may be from 0.1 to 1.5 MPa (e.g.,
0.1 to 0.4 MPa).
[0078] In another variant with a sodium salt, the temperature is
directionally lower and may be from 110.degree. C. to 155.degree.
C. (e.g., 120.degree. C. to 140.degree. C.) and the pressure may be
from 0.1 to 2.0 MPa (e.g., 0.3 to 1.5 MPa).
[0079] The carboxylation is usually carried out in a diluent such
as hydrocarbons or alkylate (e.g., benzene, toluene, xylene, and
the like). In this case, the weight ratio of solvent to the alkali
metal salt of the alkyl-substituted hydroxyaromatic compound may
range from 0.1:1 to 5:1 (e.g., 0.3:1 to 3:1).
[0080] In another variant, no solvent is used. In this case,
carboxylation is conducted in the presence of diluent oil in order
to avoid a too viscous material. The weight ratio of diluent oil to
the alkali metal salt of the alkyl-substituted hydroxyaromatic
compound may range from 0.1:1 to 2:1 (e.g., from 0.2:1 to 1:1, or
from 0.2:1 to 0.5:1).
[0081] (D) Acidification
[0082] The alkali metal alkyl-substituted hydroxyaromatic
carboxylate produced above is then contacted with at least one acid
capable of converting the alkali metal alkyl-substituted
hydroxyaromatic carboxylate to an alkyl-substituted hydroxyaromatic
carboxylic acid. Such acids are well known in the art to acidify
the aforementioned alkali metal salt. Usually hydrochloric acid or
aqueous sulfuric acid is utilized.
[0083] (E) Overbasing
[0084] Overbasing of the alkylated hydroxyaromatic carboxylic acid
may be carried out by any method known by a person skilled in the
art to produce an overbased alkaline earth metal alkyl-substituted
hydroxyaromatic carboxylate detergent.
[0085] In one embodiment, the overbasing reaction is carried out in
a reactor by reacting the alkylated hydroxyaromatic carboxylic acid
with lime (i.e., alkaline earth metal hydroxide) in the presence of
carbon dioxide, an aromatic solvent (e.g., xylene), and a
hydrocarbyl alcohol (e.g. methanol).
[0086] The degree of overbasing may be controlled by the quantity
of the alkaline earth metal hydroxide, carbon dioxide and the
reactants added to the reaction mixture and the reaction conditions
used during the carbonation process.
[0087] The weight ratios of reagents used (methanol, xylene, slaked
lime and CO.sub.2) may correspond to the following weight ratios:
xylene to slaked lime from 1.5:1 to 7:1 (e.g., from 2:1 to 4:1);
methanol to slaked lime from 0.25:1 to 4:1 (e.g., from 0.4:1 to
1.2:1); CO.sub.2 to slaked lime in a molar ratio of from 0.5:1 to
1.3:1 (e.g., from 0.7:1 to 1.0:1); C.sub.1-C.sub.4 carboxylic acid
to alkaline metal base alkylhydroxyaromatic carboxylate in a molar
ratio of from 0.02:1 to 1.5:1 (e.g., 0.1:1 to 0.7:1).
[0088] Lime is added as a slurry (i.e., as a pre-mixture of lime,
methanol, xylene) and CO.sub.2 is introduced over a period of 1
hour to 4 hours, at a temperature between 20.degree. C. and
65.degree. C.
[0089] Optionally, for each of the processes described above,
predistillation, centrifugation and distillation may be utilized to
remove solvent and crude sediment. Water, methanol and a portion of
the xylene may be eliminated by heating between 110.degree. C. and
134.degree. C. This may be followed by centrifugation to eliminate
unreacted lime. Finally, xylene may be eliminated by heating under
vacuum in order to reach a flash point of at least about
160.degree. C. as determined with the Pensky-Martens Closed Cup
(PMCC) Tester described in ASTM D93.
[0090] Other Performance Additives
[0091] The formulated lubricating oil of the present disclosure may
additionally contain one or more of the other commonly used
lubricating oil performance additives. Such optional components may
include other detergents, dispersants, antiwear agents,
antioxidants, friction modifiers, corrosion inhibitors, rust
inhibitors, demulsifiers, foam inhibitors, viscosity modifiers,
pour point depressants, non-ionic surfactants, thickeners, and the
like. Some are discussed in further detail below.
[0092] Detergents
[0093] In addition to the overbased alkaline earth metal
hydroxyaromatic carboxylate detergent which is an essential
component of the present disclosure, other detergents may also be
present.
[0094] A detergent is an additive that reduces formation of piston
deposits, for example high-temperature varnish and lacquer deposits
in engines; it normally has acid-neutralizing properties and is
capable of keeping finely-divided solids in suspension. Most
detergents are based on metal "soaps", that is metal salts of
acidic organic compounds.
[0095] Detergents generally comprise a polar head with a long
hydrophobic tail, the polar head comprising the metal salt of the
acidic organic compound. The salts may contain a substantially
stoichiometric amount of the metal when they are usually described
as normal or neutral salts and would typically have a TBN at 100%
active mass of from 0 to <100 mg KOH/g. Large amounts of a metal
base can be included by reaction of an excess of a metal compound,
such as an oxide or hydroxide, with an acidic gas such as carbon
dioxide.
[0096] The resulting overbased detergent comprises neutralized
detergent as an outer layer of a metal base (e.g., carbonate)
micelle. Such overbased detergents may have a TBN at 100% active
mass of 100 mg KOH/g or greater (e.g., 200 to 500 mg KOH/g or
more).
[0097] Suitably, other detergents that may be used include
oil-soluble neutral and overbased sulfonates, phenates, sulfurized
phenates, thiophosphonates, salicylates and naphthenates and other
oil-soluble carboxylates of a metal, particularly alkali metal or
alkaline earth metals (e.g., Li, Na, K, Ca and Mg). The most
commonly used metals are Ca and Mg, which may both be present in
detergents used in lubricating compositions, and mixtures of Ca
and/or Mg with Na. Detergents may be used in various
combinations.
[0098] Other detergents can be present at 0.5 to 30 wt. % of the
lubricating oil composition.
[0099] Dispersants
[0100] During engine operation, oil-insoluble oxidation by-products
are produced. Dispersants help keep these by-products in solution,
thus diminishing their deposition on metal surfaces. Dispersants
are often known as ashless-type dispersants because, prior to
mixing in a lubricating oil composition, they do not contain
ash-forming metals and they do not normally contribute any ash when
added to a lubricant. Ashless-type dispersants are characterized by
a polar group attached to a relatively high molecular or weight
hydrocarbon chain. Typical ashless dispersants include
N-substituted long chain alkenyl succinimides. Examples of
N-substituted long chain alkenyl succinimides include
polyisobutylene succinimide with number average molecular weight of
the polyisobutylene substituent in a range of 500 to 5000 Daltons
(e.g., 900 to 2500 Daltons). Succinimide dispersants and their
preparation are disclosed, for instance in U.S. Pat. Nos. 4,234,435
and 7,897,696. Succinimide dispersants are typically an imide
formed from a polyamine, typically a poly(ethyleneamine).
[0101] In some embodiments the lubricant composition comprises at
least one polyisobutylene succinimide dispersant derived from
polyisobutylene with number average molecular weight in the range
of 500 to 5000 Daltons (e.g., 900 to 2500 Daltons). The
polyisobutylene succinimide may be used alone or in combination
with other dispersants.
[0102] The dispersant may also be post-treated by conventional
methods by reaction with any of a variety of agents. Among these
agents are boron compounds (e.g., boric acid) and cyclic carbonates
(ethylene carbonate).
[0103] Another class of dispersants includes Mannich bases. Mannich
bases are materials that are formed by the condensation of a higher
molecular weight, alkyl substituted phenol, a polyalkylene
polyamine, and an aldehyde such as formaldehyde. Mannich bases are
described in more detail in U.S. Pat. No. 3,634,515.
[0104] Another class of dispersant includes high molecular weight
esters, prepared by reaction of a hydrocarbyl acylating agent and a
polyhydric aliphatic alcohol such as glycerol, pentaerythritol, or
sorbitol. Such materials are described in more detail in U.S. Pat.
No. 3,381,022.
[0105] Another class of dispersants includes high molecular weight
ester amides.
[0106] The dispersant can be present at 0.1 to 10 wt. % of the
lubricating oil composition.
[0107] Antiwear Agents
[0108] Anti-wear agents reduce friction and excessive wear and are
usually based on compounds containing sulfur or phosphorous or
both. Noteworthy are dihydrocarbyl dithiophosphate metal salts
wherein the metal may be an alkali or alkaline earth metal, or
aluminum, lead, tin, molybdenum, manganese, nickel, copper, or
zinc. Zinc dihydrocarbyl dithiophosphates (ZDDP) are oil-soluble
salts of dihydrocarbyl dithiophosphoric acids and may be
represented by the following formula:
Zn[SP(S)(OR)(OR')].sub.2
wherein R and R' may be the same or different hydrocarbyl radicals
containing from 1 to 18 (e.g., 2 to 12) carbon atoms. To obtain oil
solubility, the total number of carbon atoms (i.e., R and R') in
the dithiophosphoric acid will generally be 5 or greater.
[0109] The antiwear agent can be present at 0.1 to 6 wt. % of the
lubricating oil composition.
[0110] Antioxidants
[0111] 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.
[0112] Useful antioxidants include hindered phenols. Hindered
phenol antioxidants often contain a secondary butyl and/or a
tertiary butyl group as a sterically hindering group. The phenol
group may be further substituted with a hydrocarbyl group
(typically linear or branched alkyl) and/or a bridging group
linking to a second aromatic group. Examples of hindered phenol
antioxidants include 2,6-di-tert-butylphenol,
2,6-di-tert-butylcresol, 2,4,6-tri-tert-butylphenol,
2,6-di-alkyl-phenolic propionic ester derivatives, and bisphenols
such as 4,4'-bis(2,6-di-tert-butylphenol) and
4,4'-methylene-bis(2,6-di-tert-butylphenol).
[0113] Sulfurized alkylphenols and alkali and alkaline earth metal
salts thereof are also useful as antioxidants.
[0114] Non-phenolic antioxidants which may be used include aromatic
amine antioxidants such as diarylamines and alkylated diarylamines.
Particular examples of aromatic amine antioxidants include
phenyl-.alpha.-naphthylamine, 4,4'-dioctyldiphenylamine,
butylated/octylated diphenylamine, nonylated diphenylamine, and
octylated phenyl-.alpha.-naphthylamine.
[0115] The antioxidant can be present at 0.01 to 5 wt. % of the
lubricating oil composition.
[0116] Friction Modifiers
[0117] A friction modifier is any material that can alter the
coefficient of friction of a surface lubricated by any lubricant or
fluid containing such material. Suitable friction modifiers may
include fatty amines, esters such as borated glycerol esters, fatty
phosphites, fatty acid amides, fatty epoxides, borated fatty
epoxides, alkoxylated fatty amines, borated alkoxylated fatty
amines, metal salts of fatty acids, or fatty imidazolines, and
condensation products of carboxylic acids and
polyalkylene-polyamines. As used herein, the term "fatty" in
relation to friction modifiers means a carbon chain having 10 to 22
carbon atoms, typically a straight carbon chain. Molybdenum
compounds are also known as friction modifiers. The friction
modifier can be present at 0.01 to 5 wt. % of the lubricating oil
composition.
[0118] Rust Inhibitors
[0119] Rust inhibitors generally protect lubricated metal surfaces
against chemical attack by water or other contaminants. Suitable
rust inhibitors may include nonionic suitable rust inhibitors
include nonionic polyoxyalkylene agents (e.g., polyoxyethylene
lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene
nonylphenyl ether, polyoxyethylene octylphenyl ether,
polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether,
polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol
monooleate, and polyethylene glycol monooleate); stearic acid and
other fatty acids; dicarboxylic acids; metal soaps; fatty acid
amine salts; metal salts of heavy sulfonic acid; partial carboxylic
acid esters of polyhydric alcohols; phosphoric esters;
(short-chain) alkenyl succinic acids, partial esters thereof and
nitrogen-containing derivatives thereof; and synthetic
alkarylsulfonates (e.g., metal dinonylnaphthalene sulfonates). Such
additives can be present at 0.01 to 5 wt. % of the lubricating oil
composition.
[0120] Demulsifiers
[0121] Demulsifiers promote oil-water separation in lubricating oil
compositions exposed to water or steam. Suitable demulsifiers
include trialkyl phosphates, and various polymers and copolymers of
ethylene glycol, ethylene oxide, propylene oxide, or mixtures
thereof. Such additives can be present at 0.01 to 5 wt. % of the
lubricating oil composition.
[0122] Foam Inhibitors
[0123] Foam inhibitors retard the formation of stable foams.
Silicones and organic polymers are typical foam inhibitors. For
example, polysiloxanes, such as silicon oil, or
polydimethylsiloxane, provide foam inhibiting properties. Further
foam inhibitors include copolymers of ethyl acrylate and
2-ethylhexyl acrylate and optionally vinyl acetate. Such additives
can be present at 0.001 to 1 wt. % of the lubricating oil
composition.
[0124] Viscosity Modifiers
[0125] Viscosity modifiers provide lubricants with high and low
temperature operability. These additives impart shear stability at
elevated temperatures and acceptable viscosity at low temperatures.
Suitable viscosity modifier may include polyolefins, olefin
copolymers (OCP), ethylene/propylene copolymers, polyisobutenes,
hydrogenated styrene-isoprene polymers, styrene/maleic ester
copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated
isoprene polymers, alpha-olefin maleic anhydride copolymers,
polymethacrylates, polyacrylates, polyalkyl styrenes, and
hydrogenated alkenyl aryl conjugated diene copolymers. Such
additives can be present at 0.1 to 15 wt. % of the lubricating oil
composition.
[0126] Pour Point Depressants
[0127] Pour point depressants lower the minimum temperature at
which a fluid will flow or can be poured. Examples of suitable pour
point depressants include polymethacrylates, polyacrylates,
polyacrylamides, condensation products of haloparaffin waxes and
aromatic compounds, vinyl carboxylate polymers, and terpolymers of
dialkylfumarates, vinyl esters of fatty acids and allyl vinyl
ethers. Such additives can be present at 0.01 to 1.0 wt. % of the
lubricating oil composition.
[0128] Non-ionic Surfactants
[0129] Non-ionic surfactants such as alkylphenol may improve
asphaltene handling during engine operation. Examples of such
materials include alkylphenol having an alkyl substituent from a
straight chain or branched alkyl group having from 9 to 30 carbon
atoms. Other examples include alkyl benzenol, alkylnaphthol and
alkyl phenol aldehyde condensates where the aldehyde is
formaldehyde such that the condensate is a methylene-bridged
alkylphenol. Such additives can be present at 0.1 to 20 wt. % of
the lubricating oil composition.
[0130] Thickeners
[0131] Thickeners such as polyisobutylene (PIB) and polyisobutenyl
succinic anhydride (PIBSA) can be used to thicken lubricants. PIB
and PIBSA are commercially available materials from several
manufacturers. The PIB can be used in the manufacture of PIBSA and
is typically a viscous oil-miscible liquid, having a weight average
molecular weight in the range of 1000 to 8000 Daltons (e.g., 1500
to 6000 Daltons) and a kinematic viscosity at 100.degree. C. in a
range of 2000 to 6,000 mm.sup.2/s. Such additives can be present at
1 to 20 wt. % of the lubricating oil composition.
[0132] Use of the Lubricating Oil Composition
[0133] The lubricant compositions may be effective as engine oil or
crankcase lubricating oils for compression-ignited internal
combustion engines, including marine diesel engines, stationary gas
engines, and the like.
[0134] The internal combustion engine may be a 2-stroke or 4-stroke
engine.
[0135] In an embodiment, the internal combustion engine is a marine
diesel engine. The marine diesel engine may be a medium-speed
4-stroke compression-ignited engine having a speed of 250 to 1100
rpm or a low-speed crosshead 2-stroke compression-ignited engine
having a speed of 200 rpm or less (e.g., 60 to 200 rpm).
[0136] The marine diesel engine may be lubricated with a marine
diesel cylinder lubricant (typically in a 2-stroke engine), a
system oil (typically in a 2-stroke engine), or a crankcase
lubricant (typically a 4-stroke engine).
[0137] The term "marine" does not restrict the engines to those
used in water-borne vessels; as is understood in the art, it also
includes those for other industrial applications such as auxiliary
power generation for main propulsion and stationary land-based
engines for power generation.
[0138] In some embodiments, the internal combustion engine may be
fueled with a residual fuel, a marine residual fuel, a low sulfur
marine residual fuel, a marine distillate fuel, a low sulfur marine
distillate fuel, or a high sulfur fuel.
[0139] A "residual fuel" refers to a material combustible in large
marine engines which has a carbon residue, as determined by ISO
10370:2014, of at least 2.5 wt. % (e.g., at least 5 wt. %, or at
least 8 wt. %), a viscosity at 50.degree. C. of greater than 14.0
mm.sup.2/s, such as the marine residual fuels defined in ISO
8217:2017 ("Petroleum products--Fuels (class F)--Specifications of
marine fuels"). Residual fuels are primarily the non-boiling
fractions of crude oil distillation. Depending on the pressures and
temperatures in refinery distillation processes, and the types of
crude oils, slightly more or less gas oil that could be boiled off
is left in the non-boiling fraction, creating different grades of
residual fuels.
[0140] A "marine residual fuel" is a fuel meeting the specification
of a marine residual fuel as set forth in ISO 8217:2017. A "low
sulfur marine residual fuel" is a fuel meeting the specification of
a marine residual fuel as set forth in ISO 8217:2017 that, in
addition, has 1.5 wt. % or less, or even 0.5 wt. % or less, of
sulfur, relative to the total weight of the fuel, wherein the fuel
is a residual product of a distillation process.
[0141] Distillate fuel is composed of petroleum fractions of crude
oil that are separated in a refinery by a boiling or "distillation"
process. A "marine distillate fuel" is a fuel meeting the
specification of a marine distillate fuel as set forth in ISO
8217:2017. A "low sulfur marine distillate fuel" is a fuel meeting
the specification of a marine distillate fuel as set forth in ISO
8217:2017 that, in addition, has about 0.1 wt. % of less, 0.05 wt.
% or less, or even 0.005 wt. % or less of sulfur, relative to the
total weight of the fuel, wherein the fuel is a distillation cut of
a distillation process.
[0142] A "high sulfur fuel" is a fuel having greater than 1.5 wt. %
of sulfur, relative to the total weight of the fuel.
[0143] The internal combustion engine can also be operable with a
"gaseous fuel" such as a methane-dominated fuel (e.g., natural
gas), a biogas, a gasified liquefied gas, or a gasified liquefied
natural gas (LNG).
Examples
[0144] The following illustrative examples are intended to be
non-limiting.
Test Methods
[0145] Low temperature performance of the lubricants was evaluated
by pour point, according to ASTM D6749.
Detergents
[0146] Table 2 provides a summary of properties of the carboxylate
detergents used in the examples below.
TABLE-US-00002 TABLE 2 TBN (as TBN Alkyl- received), (actives), Ca
Carboxylate Substituent mg mg Basicity Content, Detergent Source
KOH/g KOH/g Index wt. % A C.sub.20--C.sub.28 150 230 2.4 5.35 NAO B
Isomerized 420 620 9.4 15.0 C.sub.20--C.sub.24 NAO C Isomerized 180
225 2.4 6.4 C.sub.20--C.sub.24 NAO.sup.(1) D Isomerized 140 210 1.4
5.0 C.sub.20--C.sub.24 NAO.sup.(1)/ propylene tetramer E
C.sub.20--C.sub.28 140 210 1.4 5.0 NAO/ propylene tetramer
.sup.(1)Isomerization Level = 0.16
Example 1 and Comparative Example A
[0147] A series of 6 BN marine system oil lubricants were
formulated with Group I base oil, an overbased calcium
alkyl-substituted hydroxyaromatic carboxylate detergent, an aminic
antioxidant and a zinc dialkyldithiophosphate (ZDDP). The low
temperature properties of the lubricants were evaluated and are
summarized in Table 3. Weight percentages reported for the
additives in Table 3 are on an as-received basis.
TABLE-US-00003 TABLE 3 Ex. 1 Comp. Ex. A Components Carboxylate
Detergent A, wt. % -- 4.00 Carboxylate Detergent C, wt. % 3.16 --
Antioxidant, wt. % 0.50 0.50 ZDDP, wt. % 0.70 0.70 150N Group I
Base Oil, wt. % 3.46 4.14 600N Group I Base Oil, wt. % 92.18 90.66
Lubricant Properties TBN, mg KOH/g 6.5 6.8 KV.sub.100, mm.sup.2/s
12.05 12.01 Ca, wt. % 0.24 0.25 P, ppm 571 579 Zn, ppm 666 679 Pour
Point, .degree. C. -30 -12
Example 2 and Comparative Example B
[0148] A series of marine 15 BN TPEO lubricants were formulated
with Group II base oil, an overbased calcium alkyl-substituted
hydroxyaromatic carboxylate detergent, an overbased calcium
branched-chain alkylphenate detergent derived from propylene
tetramer, an ashless dispersant, a viscosity index improver (VII),
a demulsifier and a ZDDP. The low temperature properties of the
lubricants were evaluated and are summarized in Table 4. Weight
percentages reported for the additives in Table 4 are on an
as-received basis.
TABLE-US-00004 TABLE 4 Ex. 2 Comp. Ex. B Cornponents Carboxylate
Detergent A, wt. % -- 8.47 Carboxylate Detergent C, wt. % 6.68 --
Ca Phenate Detergent, wt. % 2.00 2.00 Dispersant, wt. % 2.00 2.00
Demulsifier, wt. % 0.05 0.05 ZDDP, wt. % 0.70 0.70 24 SSI OCP VII
2.00 2.00 600R Group II Base Oil, wt. % 81.69 78.50 150N Group I
Base Oil, wt. % 4.88 6.28 Lubricant Properties TBN, mg KOH/g 14.7
15.5 KV.sub.100, mm.sup.2/s 14.93 15.02 Ca, wt. % 0.56 0.58 P, ppm
576 559 Zn, ppm 597 580 Pour Point, .degree. C. -30 -12
Example 3 and Comparable Example C
[0149] A series of 15 BN marine cylinder lubricants were formulated
with Group I base oil, a combination of overbased calcium
alkyl-substituted hydroxyaromatic carboxylate detergents, an
ashless dispersant and a PIB thickener. The low temperature
properties of the lubricants were evaluated and are summarized in
Table 5. Weight percentages reported for the additives in Table 5
are on an as-received basis.
TABLE-US-00005 TABLE 5 Ex. 3 Comp. Ex. C Components Carboxylate
Detergent A, wt. % -- 3.95 Carboxylate Detergent B, wt. % 1.76 1.76
Carboxylate Detergent C, wt. % 4.05 -- Dispersant, wt. % 4.00 4.00
1000 MW PIB, wt. % 4.00 4.00 600N Group I Base Oil, wt. % 71.06
71.16 Bright Stock, wt. % 15.12 15.13 Lubricant Properties TBN, mg
KOH/g 15.0 13.5 KV.sub.100, mm.sup.2/s 19.35 19.14 Ca, wt. % 0.60
0.55 Pour Point, .degree. C. -27 -18
Examples 4-5 and Comparative Example D
[0150] A series of 40 BN TPEO lubricants were formulated with Group
I base oil, a combination of overbased calcium alkyl-substituted
hydroxyaromatic carboxylate detergents, a demulsifier, ZDDP, and a
C.sub.20-C.sub.24 alkylphenol non-ionic surfactant derived from
isomerized olefins.
[0151] The low temperature properties, deposit control performance,
and oxidative stability of the lubricants were evaluated. The
results are summarized in Table 6. Weight percentages reported for
the additives in Table 6 are on an as-received basis.
TABLE-US-00006 TABLE 6 Ex. 4 Ex. 5 Comp. Ex. D Components
Carboxylate Detergent B, wt. % 7.06 7.06 7.06 Carboxylate Detergent
C, wt. % 5.26 -- -- Carboxylate Detergent D, wt. % -- 7.14 --
Carboxylate Detergent E, wt. % -- -- 7.14 Demulsifier, wt. % 0.05
0.05 0.05 ZDDP, wt. % 0.70 0.70 0.70 C.sub.20--C.sub.24
alkylphenol, wt. % 2.00 2.00 2.00 600N Group I Base Oil, wt. %
77.28 77.17 77.95 Bright Stock, wt. % 7.65 5.88 3.10 Lubricant
Properties TBN, mg KOH/g 39.7 40.0 39.3 KV.sub.100, mm.sup.2/s
14.02 14.45 14.01 Ca, wt. % 1.53 1.53 1.54 P, ppm 580 569 571 Zn,
ppm 632 618 621 Pour Point, .degree. C. -21 -21 -12
Examples 6-7 and Comparative Examples E-F
[0152] A series of 70 BN marine cylinder lubricants were formulated
with Group I or Group II base oil, an overbased calcium
alkyl-substituted hydroxyaromatic carboxylate detergent, an
overbased sulfurized calcium alkylphenate detergent derived either
from propylene tetramer or isomerized C.sub.20-C.sub.24 olefins, an
ashless dispersant, a thickener, and, optionally, an overbased
calcium sulfonate detergent, a ZDDP and a VII. The low temperature
properties of the lubricants were evaluated and are summarized in
Table 7. Weight percentages reported for the additives in Table 7
are on an as-received basis.
TABLE-US-00007 TABLE 7 Comp. Comp. Ex. 6 Ex. E Ex. 7 Ex. F
Components Carboxylate Detergent A, wt. % -- 10.00 -- --
Carboxylate Detergent C, wt. % 7.89 -- -- -- Carboxylate Detergent
D, wt. % -- -- 10.71 Carboxylate Detergent E, wt. % -- -- -- 10.71
Ca Alkylphenate (propylene -- 20.91 -- -- tetramer) Detergent, wt.
% Ca Alkylphenate (isomerized 20.91 -- -- -- C.sub.20--C.sub.24
NAO) Detergent, wt. % Ca Sulfonate Detergent, wt. % -- -- 12.94
12.94 Dispersant, wt. % 0.50 0.50 0.50 0.50 ZDDP, wt. % 0.70 0.70
-- -- 50 SSI OCP VII, wt. % 2.00 2.00 -- -- 2300 MW PIB Thickener,
wt. % 2.00 2.00 -- -- 1000 MW PIBSA Thickener, wt. % -- -- 4.00
4.00 600R Group II Base Oil, wt. % -- -- 67.82 67.14 600N Group I
Base Oil, wt. % 65.99 59.37 -- -- Bright Stock, wt. % -- 4.52 -- --
Lubricant Properties TBN, mg KOH/g 66.4 70.2 68.8 70.2 KV.sub.100,
mm.sup.2/s 19.97 19.45 19.32 19.95 Ca, wt. % 2.70 2.76 2.79 2.86
Pour Point, .degree. C. -27 -15 -33 -24
Example 8 and Comparative Example G
[0153] A series of 140 BN marine cylinder lubricants were
formulated with Group II base oil, an overbased calcium
alkyl-substituted hydroxyaromatic carboxylate detergent, an
overbased sulfurized calcium phenate detergent, an overbased
calcium sulfonate detergent, and an ashless dispersant. The low
temperature properties of the lubricants were evaluated and are
summarized in Table 8. Weight percentages reported for the
additives in Table 8 are on an as-received basis.
TABLE-US-00008 TABLE 8 Ex. 8 Comp. Ex. G Components Carboxylate
Detergent D, wt. % 10.71 -- Carboxylate Detergent E, wt. % -- 10.71
Ca Alkylphenate Detergent, wt. % 4.00 4.00 Ca Sulfonate Detergent,
wt. % 28.33 28.33 Dispersant, wt. % 4.00 4.00 600R Group II Base
Oil, wt. % 52.96 52.96 Lubricant Properties TBN, mg KOH/g 137.0
138.0 KV.sub.100, mm.sup.2/s 27.12 27.58 Pour Point, .degree. C.
-24 -12
Example 9 and Comparative Example H
[0154] A series of 200 BN marine cylinder lubricants were
formulated with Group I base oil, an overbased calcium
alkyl-substituted hydroxyaromatic carboxylate detergent, an
overbased calcium sulfonate detergent, and an ashless dispersant.
The low temperature properties of the lubricants were evaluated and
are summarized in Table 9. Weight percentages reported for the
additives in Table 9 are on an as-received basis.
TABLE-US-00009 TABLE 9 Ex. 9 Comp. Ex. H Cornponents Carboxylate
Detergent A, wt. % -- 16.67 Carboxylate Detergent C, wt. % 13.16 --
Ca Sulfonate Detergent, wt. % 41.18 41.18 Dispersant, wt. % 4.00
4.00 150N Group I Base Oil, wt. % 11.04 23.69 Lubricant Properties
TBN, mg KOH/g 195.0 197.0 KV.sub.100, mm.sup.2/s 21.82 26.45 Pour
Point, .degree. C. -18 -9
* * * * *