U.S. patent application number 14/174884 was filed with the patent office on 2014-08-07 for marine engine lubrication.
This patent application is currently assigned to Infineum International Limited. The applicant listed for this patent is Infineum International Limited. Invention is credited to Joshua L. Bradley-Shaw, James C. Dodd.
Application Number | 20140221261 14/174884 |
Document ID | / |
Family ID | 47709969 |
Filed Date | 2014-08-07 |
United States Patent
Application |
20140221261 |
Kind Code |
A1 |
Dodd; James C. ; et
al. |
August 7, 2014 |
MARINE ENGINE LUBRICATION
Abstract
Lubricant additives comprising as overbased metal
hydrocarbyl-substituted hydroxybenzoate detergent dispersed in
diluent and a polyalkenyl-substituted carboxlic acid anhydride
dispersed in a diluent oil containing 50 mass % or more of a
basestock containing greater than or equal to 90% saturates and
less than or equal to 0.03% sulphur or a mixture thereof are
blended, in minor amounts, with a high saturates content oil of
lubricating viscosity, in a major amount, to give trunk piston
marine engine lubricating oil composition for a medium-speed
four-stroke compression-ignited marine engine.
Inventors: |
Dodd; James C.; (Didcot,
GB) ; Bradley-Shaw; Joshua L.; (Edinburgh,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Infineum International Limited |
Abingdon |
|
GB |
|
|
Assignee: |
Infineum International
Limited
Abingdon
GB
|
Family ID: |
47709969 |
Appl. No.: |
14/174884 |
Filed: |
February 7, 2014 |
Current U.S.
Class: |
508/307 |
Current CPC
Class: |
C10N 2020/055 20200501;
C10M 169/045 20130101; C10M 2203/1025 20130101; C10M 2203/02
20130101; C10M 2207/262 20130101; C10N 2030/04 20130101; C10N
2040/25 20130101; C10M 2203/102 20130101; C10N 2030/52 20200501;
C10N 2030/43 20200501; C10M 141/02 20130101; C10M 2207/129
20130101; C10M 2205/028 20130101; C10M 2207/262 20130101; C10N
2010/04 20130101; C10M 2207/262 20130101; C10N 2010/04
20130101 |
Class at
Publication: |
508/307 |
International
Class: |
C10M 141/02 20060101
C10M141/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2013 |
EP |
13154467.8 |
Claims
1. A method of preparing a trunk piston marine engine lubricating
oil composition for a medium-speed four-stroke compression-ignited
marine engine comprising blending (A) a lubricant additive, in a
minor amount, comprising an overbased metal hydrocarbyl-substituted
hydroxybenzoate detergent dispersed in diluent and (B) an additive
comprising a polyalkenyl-substituted carboxylic acid anhydride as
active ingredient dispersed in a diluent oil containing 50 mass %
or more of a basestock containing greater than or equal to 90%
saturates and less than or equal to 0.03% sulphur or a mixture
thereof with (C) an oil of lubricating viscosity in a major amount
that comprises 50 mass % or more of a basestock containing greater
than or equal to 90% saturates and less than or equal to 0.03%
sulphur.
2. The method of claim 1 wherein the metal is calcium.
3. The method of claim 1, wherein the hydrocarbyl-substituted
hydroxybenzoate is a salicylate.
4. The method of claim 1, wherein the hydrocarbyl group has from 8
to 400 carbon atoms.
5. The method of claim 1, wherein the diluent oil in which (B) is
dispersed comprises 60 mass % or more of the basestock containing
greater than or equal to 90% saturates and less than or equal to
0.03% sulphur, or a mixture thereof.
6. The method of claim 5 wherein the diluent oil in which (B) is
dispersed consists of or consists essentially of the basestock
containing greater than or equal to 90% saturates and less than or
equal to 0.03% sulphur or a mixture thereof.
7. The method of claim 1, wherein the basestock is a Group II, III,
IV or V basestock.
8. The method of claim 1, wherein the polyalkenyl substituent in
(B) has from 8 to 400 carbon atoms.
9. The method of claim 1, wherein the polyalkenyl substituent in
(B) has a number average molecular weight of from 350 to 1000.
10. The method of claim 1, wherein the polyalkenyl-substituted
carboxylic acid anhydride derivative, (B), is a succinic
anhydride.
11. The method of claim 10, wherein (B) is a polyisobutene succinic
acid or anhydride.
12. The method of claim 1 wherein the diluent in (A) comprises 50
mass % or more of a basestock containing greater than or equal to
90% saturates and less than or equal to 0.03% sulphur.
13. The method of claim 1, wherein the composition has a TBN of 20
to 60.
14. The method of claim 1, wherein the basestock in the oil of
lubricating viscosity (C) is a Group II, III, IV or V
basestock.
15. A trunk piston marine engine lubricating oil composition for a
medium-speed four-stroke compression-ignited marine engine
obtainable by the method of claim 1.
16. A method of operating a trunk piston medium-speed
compression-ignited marine engine comprising (i) making a
lubricating oil composition by the method of claim 1; (ii) fuelling
the engine with a heavy fuel oil; and (iii) lubricating the
crankcase of the engine with said lubricating oil composition.
17. A lubricant additive (B) as defined in claim 1.
18. A combination or admixture of a lubricant additive (B) and a
lubricant additive (A), wherein lubricant additive (B) and
lubricant additive (A) are as defined in claim 1.
Description
FIELD OF THE INVENTION
[0001] This invention relates to trunk piston marine engine
lubrication for a medium-speed four-stroke compression-ignited
(diesel) marine engine.
BACKGROUND OF THE INVENTION
[0002] Marine trunk piston engines generally use Heavy Fuel Oil
(`HFO`) for offshore running. Heavy Fuel Oil is the heaviest
fraction of petroleum distillate and comprises a complex mixture of
molecules including up to 15% of asphaltenes, defined as the
fraction of petroleum distillate that is insoluble in an excess of
aliphatic hydrocarbon (e.g. heptane) but which is soluble in
aromatic solvents (e.g. toluene). Asphaltenes can enter the engine
lubricant as contaminants either via the cylinder or the fuel pumps
and injectors, and asphaltene precipitation can then occur,
manifested in `black paint` or `black sludge` in the engine. The
presence of such carbonaceous deposits on a piston surface can act
as an insulating layer which can result in the formation of cracks
that then propagate through the piston. If a crack travels through
the piston, hot combustion gases can enter the crankcase, possibly
resulting in a crankcase explosion.
[0003] It is therefore highly desirable that trunk piston engine
oils (`TPEO`s) prevent or inhibit asphaltene precipitation, a
problem which becomes more acute when the oil of lubricating
viscosity has a higher saturates content. The prior art describes
ways of doing this, including use of metal carboxylate detergents.
See for example, WO 2008/128656, WO 2010/115594 and WO
2010/115595.
[0004] The art does not, however, concern itself with the influence
of the diluent present in additives on the problem of asphaltene
precipitation at higher saturate levels in the oil of lubricating
viscosity in a TPEO.
SUMMARY OF THE INVENTION
[0005] It is now surprisingly found that, when the diluent oil in a
polyalkenyl carboxylic acid anhydride additive has greater than or
equal to 90% saturates and less than or equal to 0.03% sulphur, a
TPEO made therefrom and that includes a hydroxybenzoate detergent
additive, has improved asphaltene dispersancy performance when the
oil of lubricating viscosity in the TPEO is a high saturates
content oil.
[0006] Thus, a first aspect of the invention is a method of
preparing a trunk piston marine engine lubricating oil composition
for a medium-speed four-stroke compression-ignited marine engine
comprising blending (A) a lubricant additive, in a minor amount,
comprising an overbased metal hydrocarbyl-substituted
hydroxybenzoate detergent dispersed in diluent and (B) an additive
comprising a polyalkenyl-substituted carboxylic acid anhydride as
active ingredient dispersed in a diluent oil containing 50 mass %
or more of a basestock containing greater than or equal to 90%
saturates and less than or equal to 0.03% sulphur or a mixture
thereof with (C) an oil of lubricating viscosity in a major amount
that comprises 50, or 60, mass % or more of a basestock containing
greater than or equal to 90% saturates and less than or equal to
0.03% sulphur.
[0007] A second aspect of the invention is a trunk piston marine
engine lubricating oil composition for a medium-speed four-stroke
compression-ignited marine engine obtainable by the method of the
first aspect of the invention.
[0008] A third aspect of the invention is the use of a lubricant
additive as defined in the first aspect of the invention in a trunk
piston marine lubricating oil composition for a medium-speed
compression-ignited marine engine to improve, or provide similar,
asphaltene-handling during operation of said engine, fueled by a
heavy-fuel oil, and its lubrication by the composition, in
comparison with analogous operation when the additive diluent is a
Group I basestock.
[0009] A fourth aspect of the invention is a method of operating a
trunk piston medium-speed compression-ignited marine engine
comprising [0010] (i) making a lubricating oil composition by the
method of the first aspect of the invention; [0011] (ii) fueling
the engine with a heavy fuel oil; and [0012] (iii) lubricating the
crankcase of the engine with said lubricating oil composition.
[0013] A fifth aspect of the invention is a lubricant addictive
comprising (B) as defined in the first aspect of the invention,
optionally in combination with (A) as defined in the first aspect
of the invention.
[0014] In this specification, the following words and expressions,
if and when used, have the meanings ascribed below: [0015] "active
ingredients" or "(a.i.)" refers to additive material that is not
diluent or solvent; [0016] "comprising" or any cognate word
specifies the presence of stated features, steps, or integers or
components, but does not preclude the presence or addition of one
or more other features, steps, integers, components or groups
thereof; the expressions "consists of or "consists essentially of
or cognates may be embraced within "comprises" or cognates, wherein
"consists essentially of permits inclusion of substances not
materially affecting the characteristics of the composition to
which it applies; [0017] "major amount" means 50 or more mass % of
a composition; preferably 60 or more mass % of a composition; more
preferably 70 or more mass % of a composition; [0018] "minor
amount" means less than 50 mass % of a composition; preferably less
than 40 mass % of a composition; more preferably less than 30 mass
% of a composition; [0019] "TBN" means total base number as
measured by ASTM D2896. Furthermore in this specification: [0020]
"calcium content" is as measured by ASTM 4951; [0021] "phosphorus
content" is as measured by ASTM D5185; [0022] "sulphated ash
content" is as measured by ASTM D874; [0023] "sulphur content" is
as measured by ASTM D2622; [0024] "KV100" means kinematic viscosity
at 100.degree. C. as measured by ASTM D445.
[0025] Also, it will be understood that various components used,
essential as well as optimal and customary, may react under
conditions of formulation, storage or use and that the invention
also provides the product obtainable or obtained as a result of any
such reaction.
[0026] Further, it is understood that any upper and lower quantity,
range and ratio limits set forth herein may be independently
combined.
DETAILED DESCRIPTION OF THE INVENTION
[0027] The features of the invention in its various aspects, if and
where applicable, will now be discussed in more detail below.
Overbased Metal Detergent Additive (A)
[0028] A metal detergent is an additive based on so-called metal
"soaps", that is metal salts of acidic organic compounds, sometimes
referred to as surfactants. They generally comprise a polar head
with a long hydrophobic tail. Overbased metal detergents, which
comprise neutralized metal detergents as the outer layer of a metal
base (e.g. carbonate) micelle, may be provided by including large
amounts of metal base by reacting an excess of a metal base, such
as an oxide or hydroxide, with an acidic gas such as carbon
dioxide.
[0029] In the present invention, overbased metal detergents (A) are
overbased metal hydrocarbyl-substituted hydroxybenzoate, preferably
hydrocarbyl-substituted salicylate, detergents.
[0030] "Hydrocarbyl" means a group or radical that contains carbon
and hydrogen atoms and that is bonded to the remainder of the
molecule via a carbon atom. It may contain hetero atoms, i.e. atoms
other than carbon and hydrogen, provided they do not alter the
essentially hydrocarbon nature and characteristics of the group. As
examples of hydrocarbyl, there may be mentioned alkyl and alkenyl.
The overbased metal hydrocarbyl-substituted hydroxybenzoate
typically has the structure shown:
##STR00001##
wherein R is a linear or branched aliphatic hydrocarbyl group, and
more preferably an alkyl group, including straight- or
branched-chain alkyl groups. There may be more than one R group
attached to the benzene ring. M is an alkali metal (e.g. lithium,
sodium or potassium) or alkaline earth metal (e.g. calcium,
magnesium barium or strontium). Calcium or magnesium is preferred;
calcium is especially preferred. The COOM group can be in the
ortho, meta or para position with respect to the hydroxyl group;
the ortho position is preferred. The R group can be in the ortho,
meta or para position with respect to the hydroxyl group. When M is
polyvalent, it is represented fractionally in the above
formula.
[0031] Hydroxybenzoic acids are typically prepared by the
carboxylation, by the Kolbe-Schmitt process, of phenoxides, and in
that case, will generally be obtained (normally in a diluent) in
admixture with uncarboxylated phenol. Hydroxybenzoic acids may be
non-sulphurized or sulphurized, and may be chemically modified
and/or contain additional substituents. Processes for sulphurizing
a hydrocarbyl-substituted hydroxybenzoic acid are well known to
those skilled in the art and are described, for example, in US
2007/0027057.
[0032] In hydrocarbyl-substituted hydroxybenzoic acids, the
hydrocarbyl group is preferably alkyl (including straight- or
branched-chain alkyl groups), and the alkyl groups advantageously
contain 5 to 100, preferably 9 to 30, especially 14 to 24, carbon
atoms.
[0033] The term "overbased" is generally 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. The term "low-based" is used to describe metal
detergents in which the equivalent ratio of metal moiety to acid
moiety is greater than 1, and up to about 2.
[0034] By an "overbased calcium salt of surfactants" is meant an
overbased detergent in which the metal cations of the oil-insoluble
metal salt are essentially calcium cations. Small amounts of other
cations may be present in the oil-insoluble metal salt, but
typically at least 80, more typically at least 90, for example at
least 95, mole % of the cations in the oil-insoluble metal salt are
calcium ions. Cations other than calcium may be derived, for
example, from the use in the manufacture of the overbased detergent
of a surfactant salt in which the cation is a metal other than
calcium. Preferably, the metal salt of the surfactant is also
calcium.
[0035] Carbonated overbased metal detergents typically comprise
amorphous nanoparticles. Additionally, there are disclosures of
nanoparticulate materials comprising carbonate in the crystalline
calcite and vaterite forms.
[0036] The basicity of the detergents may be expressed as a total
base number (TBN). A total base number is the amount of acid needed
to neutralize all of the basicity of the overbased material. The
TBN may be measured using ASTM standard D2896 or an equivalent
procedure. The detergent may have a low TBN (i.e. a TBN of less
than 50), a medium TBN (i.e. a TBN of 50 to 150) or a high TBN
(i.e. a TBN of greater than 150, such as 150-500). In this
invention, Basicity Index is used. Basicity Index is the molar
ratio of total base to total soap in the overbased detergent. The
Basicity Index of the detergent (A) in the invention is preferably
in the range of 1 to 8, more preferably 3 to 8, such as 3 to 7,
such as 3 to 6. The Basicity Index may for example be greater than
3.
[0037] Overbased metal hydrocarbyl-substituted hydroxybenzoates can
be prepared by any of the techniques employed in the art. A general
method is as follows: [0038] 1. Neutralisation of
hydrocarbyl-substituted hydroxybenzoic acid with a molar excess of
metallic base to produce a slightly overbased metal
hydrocarbyl-substituted hydroxybenzoate complex, in a solvent
mixture consisting of a volatile hydrocarbon, an alcohol and water;
[0039] 2. Carbonation to produce colloidally-dispersed metal
carbonate followed by a post-reaction period; [0040] 3. Removal of
residual solids that are not colloidally dispersed; and [0041] 4.
Stripping to remove process solvents.
[0042] Overbased metal hydrocarbyl-substituted hydroxybenzoates can
be made by either a batch or a continuous overbasing process.
[0043] Metal base (e.g. metal hydroxide, metal oxide or metal
alkoxide), preferably lime (calcium hydroxide), may be charged in
one or more stages. The charges may be equal or may differ, as may
the carbon dioxide charges which follow them. When adding a further
calcium hydroxide charge, the carbon dioxide treatment of the
previous stage need not be complete. As carbonation proceeds,
dissolved hydroxide is converted into colloidal carbonate particles
dispersed in the mixture of volatile hydrocarbon solvent and
non-volatile hydrocarbon oil.
[0044] Carbonation may be effected in one or more stages over a
range of temperatures up to the reflux temperature of the alcohol
promoters. Addition temperatures may be similar, or different, or
may vary during each addition stage. Phases in which temperatures
are raised, and optionally then reduced, may precede further
carbonation steps.
[0045] The volatile hydrocarbon solvent of the reaction mixture is
preferably a normally liquid aromatic hydrocarbon having a boiling
point not greater than about 150.degree. C. Aromatic hydrocarbons
have been found to offer certain benefits, e.g. improved filtration
rates, and examples of suitable solvents are toluene, xylene, and
ethyl benzene.
[0046] The alkanol is preferably methanol although other alcohols
such as ethanol can be used. Correct choice of the ratio of alkanol
to hydrocarbon solvents, and the water content of the initial
reaction mixture, are important to obtain the desired product.
[0047] Oil may be added to the reaction mixture; if so, suitable
oils include hydrocarbon oils, particularly those of mineral
origin. Oils which have viscosities of 15 to 30 mm.sup.2/sec at
38.degree. C. are very suitable.
[0048] After the final treatment with carbon dioxide, the reaction
mixture is typically heated to an elevated temperature, e.g. above
130.degree. C., to remove volatile materials (water and any
remaining alkanol and hydrocarbon solvent). When the synthesis is
complete, the raw product is hazy as a result of the presence of
suspended sediments. It is clarified by, for example, filtration or
centrifugation. These measures may be used before, or at an
intermediate point, or after solvent removal.
[0049] The products are used as a diluent (or oil) dispersion. If
the reaction mixture contains insufficient oil to retain an oil
solution after removal of the volatiles, further oil should be
added. This may occur before, or at an intermediate point, or after
solvent removal.
[0050] Preferably, the diluent used for (A) comprises a basestock
containing greater than or equal to 90% saturates and less than or
equal to 0.03% sulphur. (A) may contain up to 20, 30, 40, 50, 60,
70, 80 or 90, mass % or more (such as all) of said basestock. An
example of said basestock is a Group II basestock.
Polyalkenyl-Substituted Carboxylic Acid Anhydride (B)
[0051] The anhydride may constitute at least 1 to 7, such as 1.5 to
5, mass % of the lubricating oil composition. Preferably it
constitutes 2 to 5, for example 3 to 5, mass %.
[0052] The anhydride may be mono or polycarboxylic, preferably
dicarboxylic. The polyalkenyl group preferably has from 8 to 400,
such as 8 to 100, carbon atoms.
[0053] General formulae of exemplary anhydrides may be depicted
as
##STR00002##
[0054] where R.sup.1 represents a C.sub.8 to C.sub.100 branched or
linear polyalkenyl group:
[0055] The polyalkenyl moiety may have a number average molecular
weight of from 200 to 3000, preferably from 350 to 950.
[0056] Suitable hydrocarbons or polymers employed in the formation
of the anhydrides of the present invention to generate the
polyalkenyl moieties include homopolymers, interpolymers or lower
molecular weight hydrocarbons. One family of such polymers comprise
polymers of ethylene and/or at least one C.sub.3 to C.sub.28
alpha-olefin having the formula H.sub.2C.dbd.CHR.sup.1 wherein
R.sup.1 is straight or branched chain alkyl radical comprising 1 to
26 carbon atoms and wherein the polymer contains carbon-to-carbon
unsaturation, preferably a high degree of terminal ethenylidene
unsaturation. Preferably, such polymers comprise interpolymers of
ethylene and at least one alpha-olefin of the above formula,
wherein R.sup.1 is alkyl of from 1 to 18 carbon atoms, and more
preferably is alkyl of from 1 to 8 carbon atoms, and more
preferably still of from 1 to 2 carbon atoms. Therefore, useful
alpha-olefin monomers and comonomers include, for example,
propylene, butene-1, hexene-1, octene-1,4-methylpentene-1,
decene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1,
hexadecene-1, heptadecene-1, octadecene-1, nonadecene-1, and
mixtures thereof (e.g., mixtures of propylene and butene-1, and the
like). Exemplary of such polymers are propylene homopolymers,
butene-1 homopolymers, ethylene-propylene copolymers,
ethylene-butene-1 copolymers, propylene-butene copolymers and the
like, wherein the polymer contains at least some terminal and/or
internal unsaturation. Preferred polymers are unsaturated
copolymers of ethylene and propylene and ethylene and butene-1. The
interpolymers may contain a minor amount, e.g. 0.5 to 5 mole % of a
C.sub.4 to C.sub.18 non-conjugated diolefin comonomer. However, it
is preferred that the polymers comprise only alpha-olefin
homopolymers, interpolymers of alpha-olefin comonomers and
interpolymers of ethylene and alpha-olefin comonomers. The molar
ethylene content of the polymers employed is preferably in the
range of 0 to 80%, and more preferably 0 to 60%. When propylene
and/or butene-1 are employed as comonomer(s) with ethylene, the
ethylene content of such copolymers is most preferably between 15
and 50%, although higher or lower ethylene contents may be
present.
[0057] These polymers may be prepared by polymerizing alpha-olefin
monomer, or mixtures of alpha-olefin monomers, or mixtures
comprising ethylene and at least one C.sub.3 to C.sub.28
alpha-olefin monomer, in the presence of a catalyst system
comprising at least one metallocene (e.g., a
cyclopentadienyl-transition metal compound) and an alumoxane
compound. Using this process, a polymer in which 95% or more of the
polymer chains possess terminal ethenylidene-type unsaturation can
be provided. The percentage of polymer chains exhibiting terminal
ethenylidene unsaturation may be determined by FTIR spectroscopic
analysis, titration, or C.sup.13 NMR. Interpolymers of this latter
type may be characterized by the formula
POLY--C(R.sup.1).dbd.CH.sub.2 wherein R.sup.1 is C.sub.1 to
C.sub.26 alkyl, preferably C.sub.1 to C.sub.18 alkyl, more
preferably C.sub.1 to C.sub.8 alkyl, and most preferably C.sub.1 to
C.sub.2 alkyl, (e.g., methyl or ethyl) and wherein POLY represents
the polymer chain. The chain length of the R.sup.1 alkyl group will
vary depending on the comonomer(s) selected for use in the
polymerization. A minor amount of the polymer chains can contain
terminal ethenyl, i.e., vinyl, unsaturation, i.e.
POLY--CH.dbd.CH.sub.2, and a portion of the polymers can contain
internal monounsaturation, e.g. POLY--CH.dbd.CH(R.sup.1), wherein
R.sup.1 is as defined above. These terminally-unsaturated
interpolymers may be prepared by known metallocene chemistry and
may also be prepared as described in U.S. Pat. Nos. 5,498,809;
5,663,130; 5,705,577; 5,814,715; 6,022,929 and 6,030,930.
[0058] Another useful class of polymers is polymers prepared by
cationic polymerization of isobutene, styrene, and the like. Common
polymers from this class include polyisobutenes obtained by
polymerization of a C.sub.4 refinery stream having a butene content
of about 35 to about 75 mass %, and an isobutene content of about
30 to about 60 mass %, in the presence of a Lewis acid catalyst,
such as aluminum trichloride or boron trifluoride. A preferred
source of monomer for making poly-n-butenes is petroleum
feedstreams such as Raffinate II. These feedstocks are disclosed in
the art such as in U.S. Pat. No. 4,952,739. Polyisobutylene is a
most preferred backbone of the present invention because it is
readily available by cationic polymerization from butene streams
(e.g., using AlCl.sub.3 or BF.sub.3 catalysts). Such
polyisobutylenes generally contain residual unsaturation in amounts
of about one ethylenic double bond per polymer chain, positioned
along the chain. A preferred embodiment utilizes polyisobutylene
prepared from a pure isobutylene stream or a Raffinate I stream to
prepare reactive isobutylene polymers with terminal vinylidene
olefins. Preferably, these polymers, referred to as highly reactive
polyisobutylene (HR-PIB), have a terminal vinylidene content of at
least 65%, e.g., 70%, more preferably at least 80%, most
preferably, at least 85%. The preparation of such polymers is
described, for example, in U.S. Pat. No. 4,152,499. HR-PIB is known
and HR-PJB is commercially available under the tradenames
Glissopal.TM. (from BASF) and Ultravis.TM. (from BP-Amoco).
[0059] Polyisobutylene polymers that may be employed are generally
based on a hydrocarbon chain of from 400 to 3000. Methods for
making polyisobutylene are known. Polyisobutylene can be
functionalized by halogenation (e.g. chlorination), the thermal
"ene" reaction, or by free radical grafting using a catalyst (e.g.
peroxide), as described below.
[0060] To produce (B) the hydrocarbon or polymer backbone may be
functionalized, with carboxylic anhydride-producing moieties
selectively at sites of carbon-to-carbon unsaturation on the
polymer or hydrocarbon chains, or randomly along chains using any
of the three processes mentioned above or combinations thereof, in
any sequence.
[0061] Processes for reacting polymeric hydrocarbons with
unsaturated carboxylic, anhydrides and the preparation of
derivatives from such compounds are disclosed in U.S. Pat. Nos.
3,087,936; 3,172,892; 3,215,707; 3,231,587; 3,272,746; 3,275,554;
3,381,022; 3,442,808; 3,565,804; 3,912,764; 4,110,349; 4,234,435;
5,777,025; 5,891,953; as well as EP 0 382 450 B1; CA-1,335,895 and
GB-A-1,440,219. The polymer or hydrocarbon may be functionalized,
with carboxylic acid anhydride moieties by reacting the polymer or
hydrocarbon under conditions that result in the addition of
functional moieties or agents, i.e., acid, anhydride, onto the
polymer or hydrocarbon chains primarily at sites of
carbon-to-carbon unsaturation (also referred to as ethylenic or
olefinic unsaturation) using the halogen assisted functionalization
(e.g. chlorination) process or the thermal "ene" reaction.
[0062] Selective functionalization can be accomplished by
halogenating, e.g., chlorinating or brominating the unsaturated
.alpha.-olefin polymer to about 1 to 8 mass %, preferably 3 to 7
mass % chlorine, or bromine, based on the weight of polymer or
hydrocarbon, by passing the chlorine or bromine through the polymer
at a temperature of 60 to 250.degree. C., preferably 110 to
160.degree. C., e.g., 120 to 140.degree. C., for about 0.5 to 10,
preferably 1 to 7 hours. The halogenated polymer or hydrocarbon
(hereinafter backbone) is then reacted with sufficient
monounsaturated reactant capable of adding the required number of
functional moieties to the backbone, e.g., monounsaturated
carboxylic reactant, at 100 to 250.degree. C., usually about
180.degree. C. to 235.degree. C., for about 0.5 to 10, e.g., 3 to 8
hours, such that the product obtained will contain the desired
number of moles of the monounsaturated carboxylic reactant per mole
of the halogenated backbones. Alternatively, the backbone and the
monounsaturated carboxylic reactant are mixed and heated while
adding chlorine to the hot material.
[0063] While chlorination normally helps increase the reactivity of
starting olefin polymers with monounsaturated functionalizing
reactant, it is not necessary with some of the polymers or
hydrocarbons contemplated for use in the present invention,
particularly those preferred polymers or hydrocarbons which possess
a high terminal bond content and reactivity. Preferably, therefore,
the backbone and the monounsaturated functionality reactant,
(carboxylic reactant), are contacted at elevated temperature to
cause an initial thermal "ene" reaction to take place. Ene
reactions are known.
[0064] The hydrocarbon or polymer backbone can be functionalized by
random attachment of functional moieties along the polymer chains
by a variety of methods. For example, the polymer, in solution or
in solid form, may be grafted with the monounsaturated carboxylic
reactant, as described above, in the presence of a free-radical
initiator. When performed in solution, the grafting takes place at
an elevated temperature in the range of about 100 to 260.degree.
C., preferably 120 to 240.degree. C. Preferably, free-radical
initiated grafting would be accomplished in a mineral lubricating
oil solution containing, e.g., 1 to 50 mass %, preferably 5 to 30
mass % polymer based on the initial total oil solution.
[0065] The free-radical initiators that may be used are peroxides,
hydroperoxides, and azo compounds, preferably those that have a
boiling point greater than about 100.degree. C. and decompose
thermally within the grafting temperature range to provide
free-radicals. Representative of these free-radical initiators are
azobutyronitrile, 2,5-dimethylhex-3-ene-2,5-bis-tertiary-butyl
peroxide and dicumene peroxide. The initiator, when used, typically
is used in an amount of between 0.005% and 1% by weight based on
the weight of the reaction mixture solution. Typically, the
aforesaid monounsaturated carboxylic reactant material and
free-radical initiator are used in a weight ratio range of from
about 1.0:1 to 30:1, preferably 3:1 to 6:1. The grafting is
preferably carried out in an inert atmosphere, such as under
nitrogen blanketing. The resulting grafted polymer is characterized
by having carboxylic acid (or derivative) moieties randomly
attached along the polymer chains: it being understood, of course,
that some of the polymer chains remain ungrafted. The free radical
grafting described above can be used for the other polymers and
hydrocarbons of the present invention.
[0066] The preferred monounsaturated reactants that are used to
functionalize the backbone comprise mono- and dicarboxylic acid
material, i.e., acid, or acid derivative material, including (i)
monounsaturated C.sub.4 to C.sub.10 dicarboxylic acid wherein (a)
the carboxyl groups are vicinyl, (i.e., located on adjacent carbon
atoms) and (b) at least one, preferably both, of said adjacent
carbon atoms are part of said mono unsaturation; (ii) derivatives
of (i) such as anhydrides or C.sub.1 to C.sub.5 alcohol derived
mono- or diesters of (i); (iii) monounsaturated C.sub.3 to C.sub.10
monocarboxylic acid wherein the carbon-carbon double bond is
conjugated with the carboxy group, i.e., of the structure
--C.dbd.C--CO--; and (iv) derivatives of (iii) such as C.sub.1 to
C.sub.5 alcohol derived mono- or diesters of (iii). Mixtures of
monounsaturated carboxylic materials (i)-(iv) also may be used.
Upon reaction with the backbone, the monounsaturation of the
monounsaturated carboxylic reactant becomes saturated. Thus, for
example, maleic anhydride becomes backbone-substituted succinic
anhydride, and acrylic acid becomes backbone-substituted propionic
acid. Exemplary of such monounsaturated carboxylic reactants are
fumaric acid, itaconic acid, maleic acid, maleic anhydride,
chloromaleic acid, chloromaleic anhydride, acrylic acid,
methacrylic acid, crotonic acid, cinnamic acid, and lower alkyl
(e.g., C.sub.1 to C.sub.4 alkyl) acid esters of the foregoing,
e.g., methyl maleate, ethyl fumarate, and methyl fumarate.
[0067] To provide the required functionality, the monounsaturated
carboxylic reactant, preferably maleic anhydride, typically will be
used in an amount ranging from about equimolar amount to about 100
mass % excess, preferably 5 to 50 mass % excess, based on the moles
of polymer or hydrocarbon. Unreacted excess monounsaturated
carboxylic reactant can be removed from the final dispersant
product by, for example, stripping, usually under vacuum, if
required.
[0068] The diluent used for (B) comprises a basestock containing
greater than or equal to 90% saturates and less than or equal to
0.03% sulphur. (B) may contain up to 20, 30, 40, 50, 60, 70, 80 or
90 mass % or more (such as all) of said basestock. An example of
said basestock is a Group II basestock.
Oil of Lubricating Viscosity (C)
[0069] The lubricating oils may range in viscosity from light
distillate mineral oils to heavy lubricating oils. Generally, the
viscosity of the oil ranges from 2 to 40 mm.sup.2/sec, as measured
at 100.degree. C.
[0070] Natural oils include animal oils and vegetable oils (e.g.,
caster oil, lard oil); liquid petroleum oils and hydrorefined,
solvent-treated or acid-treated mineral oils of the paraffinic,
naphthenic and mixed paraffinic-naphthenic types. Oils of
lubricating viscosity derived from coal or shale also serve as
useful base oils.
[0071] Synthetic lubricating oils include hydrocarbon oils and
halo-substituted hydrocarbon oils such as polymerized and
interpolymerized olefins (e.g., polybutylenes, polypropylenes,
propylene-isobutylene copolymers, chlorinated polybutylenes,
poly(1-hexenes), poly(1-octenes), poly(1-decenes)); alkybenzenes
(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenols); and alkylated diphenyl ethers
and alkylated diphenyl sulphides and derivative, analogs and
homologs thereof.
[0072] Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
known synthetic lubricating oils. These are exemplified by
polyoxyalkylene polymers prepared by polymerization of ethylene
oxide or propylene oxide, and the alkyl and aryl ethers of
polyoxyalkylene polymers (e.g., methyl-polyiso-propylene glycol
ether having a molecular weight of 1000 or diphenyl ether of
poly-ethylene glycol having a molecular weight of 1000 to 1500);
and mono- and polycarboxylic esters thereof, for example, the
acetic acid esters, mixed C.sub.3-C.sub.8 fatty acid esters and
C.sub.13 Oxo acid diester of tetraethylene glycol.
[0073] Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic acid,
succinic acid, alkyl succinic acids and alkenyl succinic acids,
maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric
acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic
acids, alkenyl malonic acids) with a variety of alcohols (e.g.,
butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene glycol, diethylene glycol monoether, propylene
glycol). Specific examples of such esters includes dibutyl adipate,
di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic
acid dimer, and the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid.
[0074] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.12 monocarboxylic acids and polyols and polyol
esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0075] Silicon-based oils such as the polyalkyl-, polyaryl-,
polyalkoxy- or polyaryloxysilicone oils and silicate oils comprise
another useful class of synthetic lubricants; such oils include
tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-ethylhexyl)silicate,
tetra-(4-methyl-2-ethylhexyl)silicate,
tetra-(p-tert-butyl-phenyl)silicate,
hexa-(4-methyl-2-ethylhexyl)disiloxane, poly(methyl)siloxanes and
poly(methylphenyl)siloxanes. Other synthetic lubricating oils
include liquid esters of phosphorous-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, diethyl ester of
decylphosphonic acid) and polymeric tetrahydrofurans.
[0076] Unrefined, refined and re-refined oils can be used in
lubricants of the present invention. Unrefined oils are those
obtained directly from a natural or synthetic source without
further purification treatment. For example, a shale oil obtained
directly from retorting operations; petroleum oil obtained directly
from distillation; or ester oil obtained directly from an
esterification and used without further treatment would be an
unrefined oil. Refined oils are similar to unrefined oils except
that the oil is further treated in one or more purification steps
to improve one or more properties. Many such purification
techniques, such as distillation, solvent extraction, acid or base
extraction, filtration and percolation are known to those skilled
in the art. Re-refined oils are obtained by processes similar to
those used to provide refined oils but begin with oil that has
already been used in service. Such re-refined oils are also known
as reclaimed or reprocessed oils and are often subjected to
additional processing using techniques for removing spent additives
and oil breakdown products.
[0077] The American Petroleum Institute (API) publication "Engine
Oil Licensing and Certification System", Industry Services
Department, Fourteenth Edition, December 1996, Addendum 1, December
1998 categorizes base stocks as follows: [0078] a) Group I base
stocks contain less than 90 percent saturates and/or greater than
0.03 percent sulphur and have a viscosity index greater than or
equal to 80 and less than 120 using the test methods specified in
Table E-1. [0079] b) Group II base stocks contain greater than or
equal to 90 percent saturates and less than or equal to 0.03
percent sulphur and have a viscosity index greater than or equal to
80 and less than 120 using the test methods specified in Table E-1.
[0080] c) Group III base stocks contain greater than or equal to 90
percent saturates and less than or equal to 0.03 percent sulphur
and have a viscosity index greater than or equal to 120 using the
test methods specified in Table E-1. [0081] d) Group IV base stocks
are polyalphaolefins (PAO). [0082] e) Group V base stocks include
all other base stocks not included in Group I, II, III, or IV.
[0083] Analytical Methods for Base Stock are tabulated below:
TABLE-US-00001 PROPERTY TEST METHOD Saturates ASTM D 2007 Viscosity
Index ASTM D 2270 Sulphur ASTM D 2622 ASTM D 4294 ASTM D 4927 ASTM
D 3120
[0084] The present invention embraces those of the above oils
containing greater than or equal to 90% saturates and less than or
equal to 0.03% sulphur as the oil of lubricating viscosity, eg
Group II, III, IV or V. They also include basestocks derived from
hydrocarbons synthesised by the Fischer-Tropsch process. In the
Fischer-Tropsch process, synthesis gas containing carbon monoxide
and hydrogen (or `syngas`) is first generated and then converted to
hydrocarbons using a Fischer-Tropsch catalyst. These hydrocarbons
typically require further processing in order to be useful as a
base oil. For example, they may, by methods known in the art, be
hydroisomerized; hydrocracked and hydroisomerized; dewaxed; or
hydroisomerized and dewaxed. The syngas may, for example, be made
from gas such as natural gas or other gaseous hydrocarbons by steam
reforming, when the basestock may be referred to as gas-to-liquid
("GTL") base oil; or from gasification of biomass, when the
basestock may be referred to as biomass-to-liquid ("BTL" or "BMTL")
base oil; or from gasification of coal, when the basestock may be
referred to as coal-to-liquid ("CTL") base oil.
[0085] Preferably, the oil of lubricating viscosity in this
invention contains 50 mass % or more said basestocks. It may
contain 60, such as 70, 80 or 90, mass % or more of said basestock
or a mixture thereof. The oil of lubricating viscosity may be
substantially all of said basestock or a mixture thereof.
[0086] It may be desirable, although not essential, to prepare one
or more additive packages or concentrates comprising additives,
whereby additives (A) and (B) can be added simultaneously to the
oil of lubricating viscosity (C) to form the TPEO.
[0087] The final formulations as a trunk piston engine oil may
typically contain 30, preferably 10 to 28, more preferably 12 to
24, mass % of the additive package(s), the remainder being the oil
of lubricating viscosity. The trunk piston engine oil may have a
compositional TBN (using ASTM D2896) of 20 to 60, such as, 30 to
55. For example, it may be 40 to 55 or 35 to 50. When the TBN is
high, for example 45-55, the concentration of (A) may be higher.
When the TBN is lower, for example 30 to below 45, the
concentration of (A) may be lower.
[0088] The treat rate of additives (A) and (B) contained in the
lubricating oil composition may for example be in the range of 1 to
2.5, preferably 2 to 20, more preferably 5 to 18, mass %.
Co-Additives
[0089] The lubricating oil composition of the invention may
comprise further additives, different from and additional to (A)
and (B). Such additional additives may, for example include ashless
dispersants, other metal detergents, anti-wear agents such as zinc
dihydrocarbyl dithiophosphates, anti-oxidants and demulsifiers.
EXAMPLES
[0090] The present invention is illustrated by but in no way
limited to the following examples.
Components
[0091] The following components and oils were used:
Component (A):
[0092] A set of overbased calcium salicylate detergents comprising
a mixture of a detergent having a basicity index of 8.0 and a
detergent having a basicity index of 3.0 where the diluents were
respectively SN 150 (Group 1, as a reference), and various Group II
basestocks as identified in the RESULTS tables below.
[0093] The detergents were made by solvent exchange between the
solvent present in production (e.g. xylene) and the above-mentioned
diluents.
Component (B):
[0094] A set of polyisobutene succinic anhydrides ("PIBSA") derived
from a polyisobutene having a number average molecular weight of
950, comprising 20% diluent in the form of SN150 (Group I as a
reference) and various Group II basestocks as identified in the
RESULTS tables below.
Oils of Lubricating Viscosity (C):
[0095] Oil I: an API Group I base oil known as XOM 600
[0096] Oil II: an API Group II 600R basestock from Chevron
Heavy Fuel Oil:
[0097] A heavy fuel oil, ISO-F-RMK 380.
Lubricants
[0098] Selections of the above components were blended with a major
proportion of oil of lubricating viscosity (C) to give a range of
trunk piston marine engine lubricants. Some of the lubricants are
examples of the invention; others are reference examples for
comparison purposes. The compositions of the lubricants tested when
each contained HFO are shown in the tables below under the
"Results" heading
Testing
Light Scattering
[0099] The test lubricants were evaluated for asphaltene
dispersancy using light scattering according to the Focused Beam
Reflectance Method ("FBRM"), which predicts asphaltene
agglomeration and hence `black sludge` formation.
[0100] The FBRM test method was disclosed at the 7th International
Symposium on Marine Engineering, Tokyo, 24-28 Oct. 2005, and was
published in `The Benefits of Salicylate Detergents in TPEO
Applications with a Variety of Base Stocks`, in the Conference
Proceedings. Further details were disclosed at the CIMAC Congress,
Vienna, 21-24 May 2007 and published in "Meeting the Challenge of
New Base Fluids for the Lubrication of Medium Speed Marine
Engines--An Additive Approach" in the Congress Proceedings. In the
latter paper it is disclosed that by using the FBRM method it is
possible to obtain quantitative results for asphaltene dispersancy
that predict performance for lubricant systems based on base stocks
containing greater than or less than 90% saturates, and greater
than or less than 0.03% sulphur. The predictions of relative
performance obtained from FBRM were confirmed by engine tests in
marine diesel engines.
[0101] The FBRM probe contains fibre optic cables through which
laser light travels to reach the probe tip. At the tip, an optic
focuses the laser light to a small spot. The optic is rotated so
that the focussed beam scans a circular path between the window of
the probe and the sample. As particles flow past the window they
intersect the scanning path, giving backscattered light from the
individual particles.
[0102] The scanning laser beam travels much faster than the
particles; this means that the particles are effectively
stationary. As the focussed beam reaches one edge of the particle
there is an increase in the amount of backscattered light; the
amount will decrease when the focussed beam reaches the other edge
of the particle.
[0103] The instrument measures the time of the increased
backscatter. The time period of backscatter from one particle is
multiplied by the scan speed and the result is a distance or chord
length. A chord length is a straight line between any two points on
the edge of a particle. This is represented as a chord length
distribution, a graph of numbers of chord lengths (particles)
measured as a function of the chord length dimensions in microns.
As the measurements are performed in real time the statistics of a
distribution can be calculated and tracked. FBRM typically measures
tens of thousands of chords per second, resulting in a robust
number-by-chord length distribution. The method gives an absolute
measure of the particle size distribution of the asphaltene
particles.
[0104] The Focused beam Reflectance Probe (FBRM), model Lasentec
D600L, was supplied by Mettler Toledo, Leicester, UK. The
instrument was used in a configuration to give a particle size
resolution of 1 .mu.m to 1 mm. Data from FBRM can be presented in
several ways. Studies have suggested that the average counts per
second can be used as a quantitative determination of asphaltene
dispersancy. This value is a function of both the average size and
level of agglomerate. In this application, the average count rate
(over the entire size range) was monitored using a measurement time
of 1 second per sample.
[0105] The test lubricant formulations were heated to 60.degree. C.
and stirred at 400 rpm; when the temperature reached 60.degree. C.
the FBRM probe was inserted into the sample and measurements made
for 15 minutes. An aliquot of heavy fuel oil (10% w/w) was
introduced into the lubricant formulation under stirring using a
four blade stirrer (at 400 rpm). A value for the average counts per
second was taken when the count rate had reached an equilibrium
value (typically overnight).
Results
Light Scattering
[0106] Results of the FBRM tests are summarized in the tables below
(TABLES 1 and 2).
[0107] In TABLE 1, each TPEO had a BN of 30 and comprised 0.56% of
calcium salicylate of BI 8.0, 0.51% of calcium salicylate of BI
3.0, 0.73% of a Group I diluent (for the detergent), and 0.03%
Zn.
TABLE-US-00002 TABLE 1 Oil of PIBSA PIBSA Lubricating (% active
Diluent and % Viscosity (C) Lasentec Ex matter) Saturates (Group
II) (Counts) 1 4.00 RLOP100/96 83.10 1894.94 2 4.00 Etro 4/96 83.10
1903.50 3 4.00 Nexbase 3043/95 83.10 2026.35 4 4.00 Durasyn 41/98
83.10 2144.54 5 4.00 Yubase 4/98 83.10 2222.15 6 4.00 Jurong 150/95
83.10 2862.79 7 4.00 Spectrasyn 4/98 83.10 2913.87 8 4.00 Priolube
3970/100 83.10 2982.07 Ref 1 4.00 SN150/70 83.10 3233.67 Control 1
-- -- 88.10 6793.31
[0108] The results are given in particle counts where a lower value
indicates better performance. The Control (lacking PIBSA) gave the
worst result. Ref 1, using PIBSA in a Group I diluent, gave a
better result. Best results were exhibited by Examples 1-8, each of
which used PIBSA in a high saturate diluent.
[0109] In Table 2, each TPEO had a BN of 40 and comprised 0.75% of
calcium salicylate of B1 8.0, 0.68% of calcium salicylate of B1
3.0, and 0.04% Zn. The total additive diluent was 0.98% and was
either entirely Group I (SN150) or entirely high saturate (Jurong
150 or Chevron 100).
TABLE-US-00003 TABLE 2 PIBSA Oil of Lasentec (counts) (% active
Lubricating Group I High saturate Ex matter) (C) diluent diluent
Ref 2 0 84.10 7578.11 4027.04 9 0.80 83.10 8231.84 4096.64 10 1.60
82.10 6248.28 1544.70 11 2.40 81.10 3608.86 2338.28 12 3.20 80.10
2704.36 907.70 13 4.00 79.10 2395.59 484.70 14 4.80 78.10 1972.86
262.10
[0110] The results show that performance generally improves as the
PIBSA active matter % increases, but that the improvement is much
more significant when the additive diluent is a high saturate
oil.
* * * * *