U.S. patent application number 13/721110 was filed with the patent office on 2014-01-09 for method of reducing the rate of depletion of basicity of a lubricating oil composition in use in an engine.
The applicant listed for this patent is Adam P. Marsh, Neal J. Milne. Invention is credited to Adam P. Marsh, Neal J. Milne.
Application Number | 20140011725 13/721110 |
Document ID | / |
Family ID | 47630952 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140011725 |
Kind Code |
A1 |
Marsh; Adam P. ; et
al. |
January 9, 2014 |
Method of Reducing the Rate of Depletion of Basicity of a
Lubricating Oil Composition in Use in an Engine
Abstract
Disclosed is a method of reducing the rate of depletion of
basicity (as determined by ASTM D2896) of a lubricating oil
composition in use in an engine. The lubricating oil composition
includes at least one overbased alkali or alkaline earth metal
detergent. The method comprises adding to the lubricating oil
composition one or more compounds of Formula (I): ##STR00001##
wherein: x is 1 to 50, preferably 1 to 40, more preferably 1 to 30;
R.sup.1 and R.sup.2 are H, hydrocarbyl groups having 1 to 12 carbon
atoms, or hydrocarbyl groups having 1 to 12 carbon atoms and at
least one heteroatom; R is a hydrocarbyl group having 9 to 100,
preferably 9 to 70, most preferably, 9 to 50, carbon atoms; and n
is 0 to 10, or alkaline earth metal salts thereof. The compounds of
formula (I) are preferably methylene-bridged alkyl phenols or
ethoxylated methylene-bridged alkyl phenols.
Inventors: |
Marsh; Adam P.; (Witney,
GB) ; Milne; Neal J.; (Wiltshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Marsh; Adam P.
Milne; Neal J. |
Witney
Wiltshire |
|
GB
GB |
|
|
Family ID: |
47630952 |
Appl. No.: |
13/721110 |
Filed: |
December 20, 2012 |
Current U.S.
Class: |
508/580 |
Current CPC
Class: |
C10N 2040/25 20130101;
C10M 145/20 20130101; C10N 2010/04 20130101; C10M 129/16 20130101;
C10M 2219/046 20130101; C10M 145/18 20130101; C10M 2209/101
20130101; C10N 2030/52 20200501; C10M 165/00 20130101 |
Class at
Publication: |
508/580 |
International
Class: |
C10M 129/16 20060101
C10M129/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2011 |
EP |
11194915.2 |
Claims
1. A method of reducing the rate of depletion of basicity (as
determined by ASTM D2896) of a lubricating oil composition in use
in an engine, the lubricating oil composition including at least
one oil-soluble overbased alkali or alkaline earth metal detergent,
which method comprises adding to the lubricating oil composition
one or more compounds of Formula (I): ##STR00006## wherein: x is 1
to 50, preferably 1 to 40, more preferably 1 to 30; R.sup.1 and
R.sup.2 are H, hydrocarbyl groups having 1 to 12 carbon atoms, or
hydrocarbyl groups having 1 to 12 carbon atoms and at least one
heteroatom; R is a hydrocarbyl group having 9 to 100, preferably 9
to 70, most preferably, 9 to 50, carbon atoms; and n is 0 to 10, or
alkaline earth metal salts thereof.
2. The method as claimed in claim 1, wherein n in Formula (I) is
0.
3. The method as claimed in claim 1, wherein x in Formula (I) is
1.
4. The method as claimed in claim 1, wherein R in Formula (I) is 9
to 20 carbon atoms.
5. The method as claimed claim 1, wherein R in Formula (I) is
branched.
6. The method as claimed in claim 1, wherein R.sup.1 is H, R.sup.2
is H and R is in the para position in relation to the
--O--[CH.sub.2CH.sub.2O].sub.nH group in formula (I).
7. The method as claimed in claim 1, wherein the compounds of
formula (I) include less than 1 mole % of unreacted alkyl
phenol.
8. The method as claimed in claim 1, wherein n=1 for more than 60
mole % of the compounds of formula (I).
9. The method as claimed in claim 1, wherein the alkaline earth
metal salts of the compounds of Formula (I) are calcium or
magnesium salts.
10. The method as claimed claim 1, wherein compounds of formula (I)
in which n.gtoreq.2 constitute less than 5 mole % of the compounds
of formula (I).
11. The method as claimed in claim 1, wherein the compounds of
formula (I) are methylene-bridged alkyl phenols or ethoxylated
methylene-bridged alkyl phenols.
12. The method as claimed in claim 1, wherein the lubricating oil
composition has a TBN of 4 to 100 as measured by ASTM D2896.
13. The method as claimed in claim 1, wherein the lubricating oil
composition is a marine cylinder lubricant, a trunk piston engine
oil, a gas engine oil or a crankcase lubricating oil composition.
Description
FIELD OF THE INVENTION
[0001] This invention relates to a method of reducing the rate of
depletion of basicity (as determined by ASTM D2896) of a
lubricating oil composition in use in an engine, the lubricating
oil composition including at least one oil-soluble overbased alkali
or alkaline earth metal detergent. In particular, the invention
relates to a method of reducing the rate of depletion of basicity
(as determined by ASTM D2896) of a to lubricating oil composition
in use in an engine, the lubricating oil composition including at
least one oil-soluble overbased alkali or alkaline earth metal
detergent, without increasing sulphated ash content (SASH).
Preferably, the lubricating oil composition is a marine cylinder
lubricant, a trunk piston engine oil, a gas engine oil or a
crankcase lubricating oil composition (including a passenger car
motor oil and a heavy duty diesel motor oil).
BACKGROUND OF THE INVENTION
[0002] Lubricating oil compositions include oil-soluble overbased
detergents to supply alkalinity to neutralize sulphur acids
resulting from high sulphur fuels. They also prevent harmful carbon
and sludge deposits, which can lead to engine shut-down and repair.
The overbased detergents usually have a TBN ranging from 50 to 500,
preferably 250 to 450 mg KOH/g (ASTM D2896), and are usually
overbased alkaline earth metal detergents such as overbased calcium
sulphonates, phenates and salicylates. It is important that the
basicity provided by the overbased detergents be retained as long
as possible, as this ensures longer oil life and better engine
protection over a longer period of time. It is also important that
ash levels are not increased because excessive sulphated ash levels
can result in increased deposits on pistons and exhaust gas
circuits, including heat recovery systems and after-treatment
devices.
[0003] The present invention is concerned with the problem of
reducing the rate of depletion of basicity (as determined by ASTM
D2896) of a lubricating oil composition in use in an engine. The
present invention is also concerned with the problem of reducing
the rate of depletion of basicity (as determined by ASTM D2896) of
a lubricating oil composition in use in an engine without
increasing sulphated ash content.
SUMMARY OF THE INVENTION
[0004] In accordance with a first aspect of the present invention,
there is provided a method of reducing the rate of depletion of
basicity (as determined by ASTM D2896) of a lubricating oil
composition in use in an engine, the lubricating oil composition
including at least one oil-soluble overbased alkali or alkaline
earth metal detergent, which method comprises adding to the
lubricating oil composition one or more compounds of Formula
(I):
##STR00002##
wherein: x is 1 to 50, preferably 1 to 40, more preferably 1 to 30;
R.sup.1 and R.sup.2 are H, hydrocarbyl groups having 1 to 12 carbon
atoms, or hydrocarbyl groups having 1 to 12 carbon atoms and at
least one heteroatom; R is a hydrocarbyl group having 9 to 100,
preferably 9 to 70, most preferably, 9 to 50, carbon atoms; and n
is 0 to 10, or alkaline earth metal salts of the compounds of
formula (I).
[0005] In the compounds of Formula (I), n is preferably 0. In the
compounds of Formula (I), x is preferably 1. In the compounds of
Formula (I), R is preferably 9 to 20 carbon atoms, more preferably
9 to 15. In the compounds of Formula (I), R is preferably
branched.
[0006] In the compounds of Formula (I), R.sup.1 in preferably H,
R.sup.2 is preferably H and R is preferably in the para position in
relation to the --O--[CH.sub.2CH.sub.2O].sub.nH group.
[0007] The compounds of Formula (I) are preferably
methylene-bridged alkyl phenols or ethoxylated methylene-bridged
alkyl phenols.
[0008] The compounds of Formula (I) preferably include less than 1
mole %, more preferably less than 0.5 mole % and most preferably
less than 0.1 mole % of unreacted alkyl phenol.
[0009] In the compounds of Formula (I), preferably n=1 for more
than 60, more preferably more than 70, even preferably more than
80, even preferably more than 90, or most preferably more than 95,
mole %.
[0010] In the compounds of Formula (I), preferably n.gtoreq.2, such
as di-oxyalkylated, tri-oxyalkylated and tetra-oxyalkylated,
constitutes less than 5 mole %.
[0011] The alkaline earth metal salts of the compounds of Formula
(I) are, for example, calcium, magnesium barium or strontium.
Calcium or magnesium is preferred; calcium is especially
preferred.
[0012] The lubricating oil composition is preferably a marine
cylinder lubricant, a trunk piston engine oil, a gas engine oil or
a crankcase lubricating oil composition (including a passenger car
motor oil and a heavy duty diesel motor oil).
[0013] When the lubricating oil composition is a marine cylinder
lubricant, the TBN (as measured by ASTM D2896) is preferably at
least 20, more preferably at least 40 and to about 70 mgKOH/g.
[0014] When the lubricating oil composition is a trunk piston
engine oil, the TBN (as measured by ASTM D2896) is preferably at
least 10, more preferably at least 20, and most preferably 30 to 55
mgKOH/g.
[0015] When the lubricating oil composition is a gas engine oil,
the TBN (as measured by ASTM D2896) is preferably at least 4, more
preferably 5 to 15 mgKOH/g.
[0016] When the lubricating oil composition is a crankcase oil, the
TBN (as measured by ASTM D2896) is preferably at least 5, more
preferably at least 6 to 18 mgKOH/g.
[0017] The lubricating oil composition is preferably a marine
cylinder lubricant.
[0018] In accordance with the present invention there is also
provided use of one or more compounds of Formula (I):
##STR00003##
wherein: x is 1 to 50, preferably 1 to 40, more preferably 1 to 30;
R.sup.1 and R.sup.2 are H, hydrocarbyl groups having 1 to 12 carbon
atoms, or hydrocarbyl groups having 1 to 12 carbon atoms and at
least one heteroatom; R is a hydrocarbyl group having 9 to 100,
preferably 9 to 70, most preferably, 9 to 50, carbon atoms; and n
is 0 to 10, or alkaline earth metal salts thereof, to reduce the
rate of depletion of basicity (as determined by ASTM D2896) of a
lubricating oil composition in use in an engine, the lubricating
oil composition including at least one oil-soluble overbased alkali
or alkaline earth metal detergent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 compares graphically the TAN and TBN crossover of a
reference oil, to that of the compositions of inventive Examples 1
and 2.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Compounds of Formula (I) are shown below:
##STR00004##
x is 1 to 50, preferably 1 to 40, more preferably 1 to 30; R.sup.1
and R.sup.2 are H, hydrocarbyl groups having 1 to 12 carbon atoms,
or hydrocarbyl groups having 1 to 12 carbon atoms and at least one
heteroatom; R is a hydrocarbyl group having 9 to 100, preferably 9
to 70, most preferably, 9 to 50, carbon atoms; and n is 0 to 10, or
alkaline earth metal salts thereof.
[0021] The alkaline earth metal salts of the compounds of Formula
(I) are, for example, calcium, magnesium barium or strontium.
Calcium or magnesium is preferred; calcium is especially
preferred.
[0022] In the compounds of Formula (I), n is preferably 0. In the
compounds of Formula (I), x is preferably 1. In the compounds of
Formula (I), R is preferably 9 to 20 carbon atoms, more preferably
9 to 15. In the compounds of Formula (I), R is preferably branched.
In the compounds of Formula (I), R.sup.1 and R.sup.2 are preferably
H.
[0023] In the compounds of Formula (I), R.sup.1 in preferably H,
R.sup.2 is preferably H, R is preferably in the para position in
relation to the --O--[CH.sub.2CH.sub.2O].sub.nH group, and n is
preferably 1 or more, preferably 1 to 10. For further details of
compounds of Formula (I) when n is 1 or more, reference is made to
EP 2374866A (the contents of which are incorporated herein). In the
compounds of Formula (I), preferably n=1 for more than 60, more
preferably more than 70, even preferably more than 80, even
preferably more than 90, or most preferably more than 95, mole %.
In the compounds of Formula (I), preferably n.gtoreq.2, such as
di-oxyalkylated, tri-oxyalkylated and tetra-oxyalkylated, for less
than 5 mole %.
[0024] The compounds of Formula (I) preferably include less than 1
mole %, more preferably less than 0.5 mole % and most preferably
less than 0.1 mole % of unreacted alkyl phenol.
[0025] Compounds of formula (I) have the advantage of being free of
metals. Furthermore, they do not exhibit negative interactions with
dispersants.
[0026] The compounds of Formula (I) are preferably hydrocarbyl
phenol formaldehyde condensates. The term "hydrocarbyl" as used
herein means that R is primarily composed of hydrogen and carbon
atoms and is bonded to the remainder of the molecule via a carbon
atom, but does not exclude the presence of other atoms or groups in
a proportion insufficient to detract from the substantially
hydrocarbon characteristics of the group. The hydrocarbyl group is
preferably composed of only hydrogen and carbon atoms.
Advantageously, the hydrocarbyl group is an aliphatic group,
preferably alkyl or alkylene group, especially alkyl groups, which
may be linear or branched. R is preferably an alkyl or alkylene
group. R is preferably branched.
[0027] The hydrocarbyl phenol aldehyde condensate preferably has a
weight average molecular weight (Mw), as measured by GPC, in the
range of 1000 to less than 6000, preferably less than 4000. The
hydrocarbyl phenol aldehyde condensate preferably has a number
average molecular weight (Mn), as measured by GPC, in the range of
900 to less than 4000, such as 3000. Mw/Mn is preferably in the
range of 1.10 to 1.60.
[0028] The hydrocarbyl phenol aldehyde condensate is preferably one
obtained by a condensation reaction between at least one aldehyde
or ketone or reactive equivalent thereof and at least one
hydrocarbyl phenol, in the presence of an acid catalyst such as,
for example, an alkyl benzene sulphonic acid. The product is
preferably subjected to stripping to remove any unreacted
hydrocarbyl phenol, preferably to less than 5 mass %, more
preferably to less than 3 mass %, even more preferably to less than
1 mass %, of unreacted hydrocarbyl phenol. Most preferably, the
product includes less than 0.5 mass %, such as, for example, less
than 0.1 mass % of unreacted hydrocarbyl phenol.
[0029] Although a basic catalyst can be used, an acid catalyst is
preferred. The acid catalyst may be selected from a wide variety of
acidic compounds such as, for example, phosphoric acid, sulphuric
acid, sulphonic acid, oxalic acid and hydrochloric acid. The acid
may also be present as a component of a solid material such as acid
treated clay. The amount of catalyst used may vary from 0.05 to 10
mass % or more, such as for example 0.1 to 1 mass % of the total
reaction mixture.
[0030] When n is 1 or more in Formula (I), the compounds are
preferably made by oxyalkylating a hydrocarbyl phenol condensate
with ethylene carbonate (which is preferred), propylene carbonate
or butylene carbonate. Use of a carbonate for the oxyalkylation
reaction is found to give rise to much better control of the "n"
value and quantity, in comparison with use of ethylene oxide or
propylene oxide. Furthermore, an appropriate choice of catalyst can
provide a product consisting essentially entirely of mono-oxyalkyl
(i.e. n=1) content. Sodium salts are preferred, especially the
hydroxide and carboxylates, such as stearate.
[0031] In particular, the hydrocarbyl phenol aldehyde condensate is
preferably branched dodecyl phenol formaldehyde condensate, such
as, for example, a tetrapropenyl tetramer phenol formaldehyde
condensate.
[0032] The hydrocarbyl phenol aldehyde condensate is preferably
present in the additive concentrate in an amount ranging from about
0.1 to 20 mass %, preferably from about 0.1 to 15 mass %, and more
preferably from about 0.1 to 12 mass %, based on the mass of the
concentrate.
[0033] Lubricating oil compositions of the present invention
comprise a major amount of an oil of lubricating viscosity and a
minor amount of a compound of Formula I.
[0034] Oils of lubricating viscosity useful in the context of the
present invention may be selected from natural lubricating oils,
synthetic lubricating oils and mixtures thereof. The lubricating
oil may range in viscosity from light distillate mineral oils to
heavy lubricating oils such as gasoline engine oils, mineral
lubricating oils and heavy duty diesel oils. Generally, the
viscosity of the oil ranges from about 2 centistokes to about 40
centistokes, especially from about 4 centistokes to about 20
centistokes, as measured at 100.degree. C.
[0035] Natural oils include animal oils and vegetable oils (e.g.,
castor 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. 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)); alkylbenzenes
(e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-ethylhexyl)benzenes); polyphenyls (e.g., biphenyls,
terphenyls, alkylated polyphenols); and alkylated diphenyl ethers
and alkylated diphenyl sulfides and derivative, analogs and
homologs thereof. Also useful are synthetic oils derived from a gas
to liquid process from Fischer-Tropsch synthesized hydrocarbons,
which are commonly referred to as gas to liquid, or "GTL" base
oils.
[0036] 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.
[0037] 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.
[0038] 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.
[0039] 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.
[0040] The oil of lubricating viscosity may comprise a Group I,
Group II or Group III, base stock or base oil blends of the
aforementioned base stocks. Preferably, the oil of lubricating
viscosity is a Group II or Group III base stock, or a mixture
thereof, or a mixture of a Group I base stock and one or more a
Group II and Group III. Preferably, a major amount of the oil of
lubricating viscosity is a Group II, Group III, Group IV or Group V
base stock, or a mixture thereof. The base stock, or base stock
blend preferably has a saturate content of at least 65%, more
preferably at least 75%, such as at least 85%. Most preferably, the
base stock, or base stock blend, has a saturate content of greater
than 90%. Preferably, the oil or oil blend will have a sulfur
content of less than 1%, preferably less than 0.6%, most preferably
less than 0.4%, by weight.
[0041] Preferably the volatility of the oil or oil blend, as
measured by the Noack volatility test (ASTM D5880), is less than or
equal to 30%, preferably less than or equal to 25%, more preferably
less than or equal to 20%, most preferably less than or equal 16%.
Preferably, the viscosity index (VI) of the oil or oil blend is at
least 85, preferably at least 100, most preferably from about 105
to 140.
[0042] Definitions for the base stocks and base oils in this
invention are the same as those found in the American Petroleum
Institute (API) publication "Engine Oil Licensing and Certification
System", Industry Services Department, Fourteenth Edition, December
1996, Addendum 1, December 1998. Said publication categorizes base
stocks as follows: [0043] a) Group I base stocks contain less than
90 percent saturates and/or greater than 0.03 percent sulfur and
have a viscosity index greater than or equal to 80 and less than
120 using the test methods specified in Table 1. [0044] b) Group II
base stocks contain greater than or equal to 90 percent saturates
and less than or equal to 0.03 percent sulfur and have a viscosity
index greater than or equal to 80 and less than 120 using the test
methods specified in Table 1. [0045] c) Group III base stocks
contain greater than or equal to 90 percent saturates and less than
or equal to 0.03 percent sulfur and have a viscosity index greater
than or equal to 120 using the test methods specified in Table 1.
[0046] d) Group IV base stocks are polyalphaolefins (PAO). [0047]
e) Group V base stocks include all other base stocks not included
in Group I, II, III, or IV.
TABLE-US-00001 [0047] TABLE I Analytical Methods for Base Stock
Property Test Method Saturates ASTM D 2007 Viscosity Index ASTM D
2270 Sulfur ASTM D 2622 ASTM D 4294 ASTM D 4927 ASTM D 3120
[0048] Metal-containing or ash-forming detergents function both as
detergents to reduce or remove deposits and as acid neutralizers or
rust inhibitors, thereby reducing wear and corrosion and extending
engine life. Detergents generally comprise a polar head with a long
hydrophobic tail, with the polar head comprising a metal salt of an
acidic organic compound. The salts may contain a substantially
stoichiometric amount of the metal in which case they are usually
described as normal or neutral salts, and would typically have a
total base number or TBN (as can be measured by ASTM D2896) of from
0 to 80. A large amount of a metal base may be incorporated by
reacting excess metal compound (e.g., an oxide or hydroxide) with
an acidic gas (e.g., carbon dioxide). The resulting overbased
detergent comprises neutralized detergent as the outer layer of a
metal base (e.g. carbonate) micelle. Such overbased detergents may
have a TBN of 150 or greater, and typically will have a TBN of from
250 to 500 or more.
[0049] 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 the alkali or
alkaline earth metals, e.g., sodium, potassium, lithium, calcium,
and magnesium. The most commonly used metals are calcium and
magnesium, which may both be present in detergents used in a
lubricant, and mixtures of calcium and/or magnesium with sodium.
Particularly convenient metal detergents are neutral and overbased
calcium sulfonates having TBN of from 20 to 500 TBN, and neutral
and overbased calcium phenates and sulfurized phenates having TBN
of from 50 to 450. Combinations of detergents, whether overbased or
neutral or both, may be used.
[0050] Sulfonates may be prepared from sulfonic acids which are
typically obtained by the sulfonation of alkyl substituted aromatic
hydrocarbons such as those obtained from the fractionation of
petroleum or by the alkylation of aromatic hydrocarbons. Examples
included those obtained by alkylating benzene, toluene, xylene,
naphthalene, diphenyl or their halogen derivatives such as
chlorobenzene, chlorotoluene and chloronaphthalene. The alkylation
may be carried out in the presence of a catalyst with alkylating
agents having from about 3 to more than 70 carbon atoms. The
alkaryl sulfonates usually contain from about 9 to about 80 or more
carbon atoms, preferably from about 16 to about 60 carbon atoms per
alkyl substituted aromatic moiety.
[0051] The oil soluble sulfonates or alkaryl sulfonic acids may be
neutralized with oxides, hydroxides, alkoxides, carbonates,
carboxylate, sulfides, hydrosulfides, nitrates, borates and ethers
of the metal. The amount of metal compound is chosen having regard
to the desired TBN of the final product but typically ranges from
about 100 to 220 mass % (preferably at least 125 mass %) of that
stoichiometrically required.
[0052] Metal salts of phenols and sulfurized phenols are prepared
by reaction with an appropriate metal compound such as an oxide or
hydroxide and neutral or overbased products may be obtained by
methods well known in the art. Sulfurized phenols may be prepared
by reacting a phenol with sulfur or a sulfur containing compound
such as hydrogen sulfide, sulfur monohalide or sulfur dihalide, to
form products which are generally mixtures of compounds in which 2
or more phenols are bridged by sulfur containing bridges.
[0053] Lubricating oil compositions of the present invention may
further contain one or more ashless dispersants, which effectively
reduce formation of deposits upon use in engines, when added to
lubricating oils. Ashless dispersants useful in the compositions of
the present invention comprises an oil soluble polymeric long chain
backbone having functional groups capable of associating with
particles to be dispersed. Typically, such dispersants comprise
amine, alcohol, amide or ester polar moieties attached to the
polymer backbone, often via a bridging group. The ashless
dispersant may be, for example, selected from oil soluble salts,
esters, amino-esters, amides, imides and oxazolines of long chain
hydrocarbon-substituted mono- and polycarboxylic acids or
anhydrides thereof; thiocarboxylate derivatives of long chain
hydrocarbons; long chain aliphatic hydrocarbons having polyamine
moieties attached directly thereto; and Mannich condensation
products formed by condensing a long chain substituted phenol with
formaldehyde and polyalkylene polyamine. The most common dispersant
in use is the well known succinimide dispersant, which is a
condensation product of a hydrocarbyl-substituted succinic
anhydride and a poly(alkyleneamine). Both mono-succinimide and
bis-succinimide dispersants (and mixtures thereof) are well
known.
[0054] Preferably, the ashless dispersant is a "high molecular
weight" dispersant having a number average molecular weight (
M.sub.n) greater than or equal to 4,000, such as between 4,000 and
20,000. The precise molecular weight ranges will depend on the type
of polymer used to form the dispersant, the number of functional
groups present, and the type of polar functional group employed.
For example, for a polyisobutylene derivatized dispersant, a high
molecular weight dispersant is one formed with a polymer backbone
having a number average molecular weight of from about 1680 to
about 5600. Typical commercially available polyisobutylene-based
dispersants contain polyisobutylene polymers having a number
average molecular weight ranging from about 900 to about 2300,
functionalized by maleic anhydride (MW=98), and derivatized with
polyamines having a molecular weight of from about 100 to about
350. Polymers of lower molecular weight may also be used to form
high molecular weight dispersants by incorporating multiple polymer
chains into the dispersant, which can be accomplished using methods
that are know in the art.
[0055] Preferred groups of dispersant include polyamine-derivatized
poly .alpha.-olefin, dispersants, particularly ethylene/butene
alpha-olefin and polyisobutylene-based dispersants. Particularly
preferred are ashless dispersants derived from polyisobutylene
substituted with succinic anhydride groups and reacted with
polyethylene amines, e.g., polyethylene diamine, tetraethylene
pentamine; or a polyoxyalkylene polyamine, e.g., polyoxypropylene
diamine, trimethylolaminomethane; a hydroxy compound, e.g.,
pentaerythritol; and combinations thereof. One particularly
preferred dispersant combination is a combination of (A)
polyisobutylene substituted with succinic anhydride groups and
reacted with (B) a hydroxy compound, e.g., pentaerythritol; (C) a
polyoxyalkylene polyamine, e.g., polyoxypropylene diamine, or (D) a
polyalkylene diamine, e.g., polyethylene diamine and tetraethylene
pentamine using about 0.3 to about 2 moles of (B), (C) and/or (D)
per mole of (A). Another preferred dispersant combination comprises
a combination of (A) polyisobutenyl succinic anhydride with (B) a
polyalkylene polyamine, e.g., tetraethylene pentamine, and (C) a
polyhydric alcohol or polyhydroxy-substituted aliphatic primary
amine, e.g., pentaerythritol or trismethylolaminomethane, as
described in U.S. Pat. No. 3,632,511.
[0056] Another class of ashless dispersants comprises Mannich base
condensation products. Generally, these products are prepared by
condensing about one mole of an alkyl-substituted mono- or
polyhydroxy benzene with about 1 to 2.5 moles of carbonyl
compound(s) (e.g., formaldehyde and paraformaldehyde) and about 0.5
to 2 moles of polyalkylene polyamine, as disclosed, for example, in
U.S. Pat. No. 3,442,808. Such Mannich base condensation products
may include a polymer product of a metallocene catalyzed
polymerization as a substituent on the benzene group, or may be
reacted with a compound containing such a polymer substituted on a
succinic anhydride in a manner similar to that described in U.S.
Pat. No. 3,442,808. Examples of functionalized and/or derivatized
olefin polymers synthesized using metallocene catalyst systems are
described in the publications identified supra.
[0057] The dispersant can be further post treated by a variety of
conventional post treatments such as boration, as generally taught
in U.S. Pat. Nos. 3,087,936 and 3,254,025. Boration of the
dispersant is readily accomplished by treating an acyl
nitrogen-containing dispersant with a boron compound such as boron
oxide, boron halide boron acids, and esters of boron acids, in an
amount sufficient to provide from about 0.1 to about 20 atomic
proportions of boron for each mole of acylated nitrogen
composition. Useful dispersants contain from about 0.05 to about
2.0 mass %, e.g., from about 0.05 to about 0.7 mass % boron. The
boron, which appears in the product as dehydrated boric acid
polymers (primarily (HBO.sub.2).sub.3), is believed to attach to
the dispersant imides and diimides as amine salts, e.g., the
metaborate salt of the diimide. Boration can be carried out by
adding from about 0.5 to 4 mass %, e.g., from about 1 to about 3
mass % (based on the mass of acyl nitrogen compound) of a boron
compound, preferably boric acid, usually as a slurry, to the acyl
nitrogen compound and heating with stirring at from about
135.degree. C. to about 190.degree. C., e.g., 140.degree. C. to
170.degree. C., for from about 1 to about 5 hours, followed by
nitrogen stripping. Alternatively, the boron treatment can be
conducted by adding boric acid to a hot reaction mixture of the
dicarboxylic acid material and amine, while removing water. Other
post reaction processes commonly known in the art can also be
applied.
[0058] The dispersant may also be further post treated by reaction
with a so-called "capping agent". Conventionally,
nitrogen-containing dispersants have been "capped" to reduce the
adverse effect such dispersants have on the fluoroelastomer engine
seals. Numerous capping agents and methods are known. Of the known
"capping agents", those that convert basic dispersant amino groups
to non-basic moieties (e.g., amido or imido groups) are most
suitable. The reaction of a nitrogen-containing dispersant and
alkyl acetoacetate (e.g., ethyl acetoacetate (EAA)) is described,
for example, in U.S. Pat. Nos. 4,839,071; 4,839,072 and 4,579,675.
The reaction of a nitrogen-containing dispersant and formic acid is
described, for example, in U.S. Pat. No. 3,185,704. The reaction
product of a nitrogen-containing dispersant and other suitable
capping agents are described in U.S. Pat. Nos. 4,663,064 (glycolic
acid); 4,612,132; 5,334,321; 5,356,552; 5,716,912; 5,849,676;
5,861,363 (alkyl and alkylene carbonates, e.g., ethylene
carbonate); 5,328,622 (mono-epoxide); 5,026,495; 5,085,788;
5,259,906; 5,407,591 (poly (e.g., bis)-epoxides) and 4,686,054
(maleic anhydride or succinic anhydride). The foregoing list is not
exhaustive and other methods of capping nitrogen-containing
dispersants are known to those skilled in the art.
[0059] For adequate piston deposit control, a nitrogen-containing
dispersant can be added in an amount providing the lubricating oil
composition with from about 0.03 mass % to about 0.15 mass %,
preferably from about 0.07 to about 0.12 mass %, of nitrogen.
[0060] Ashless dispersants are basic in nature and therefore have a
TBN which, depending on the nature of the polar group and whether
or not the dispersant is borated or treated with a capping agent,
may be from about 5 to about 200 mg KOH/g. However, high levels of
basic dispersant nitrogen are known to have a deleterious effect on
the fluoroelastomeric materials conventionally used to form engine
seals and, therefore, it is preferable to use the minimum amount of
dispersant necessary to provide piston deposit control, and to use
substantially no dispersant, or preferably no dispersant, having a
TBN of greater than 5. Preferably, the amount of dispersant
employed will contribute no more than 4, preferably no more than 3
mg KOH/g of TBN to the lubricating oil composition. It is further
preferable that dispersant provides no greater than 30, preferably
no greater than 25% of the TBN of the lubricating oil
composition.
[0061] Additional additives may be incorporated in the compositions
of the invention to enable them to meet particular requirements.
Examples of additives which may be included in the lubricating oil
compositions are metal rust inhibitors, viscosity index improvers,
corrosion inhibitors, oxidation inhibitors, friction modifiers,
other dispersants, anti-foaming agents, anti-wear agents and pour
point depressants. Some are discussed in further detail below.
[0062] Dihydrocarbyl dithiophosphate metal salts are frequently
used as antiwear and antioxidant agents. The metal may be an alkali
or alkaline earth metal, or aluminum, lead, tin, molybdenum,
manganese, nickel or copper. The zinc salts are most commonly used
in lubricating oil in amounts of 0.1 to 10, preferably 0.2 to 2 wt.
%, based upon the total weight of the lubricating oil composition.
They may be prepared in accordance with known techniques by first
forming a dihydrocarbyl dithiophosphoric acid (DDPA), usually by
reaction of one or more alcohol or a phenol with P.sub.2S.sub.5 and
then neutralizing the formed DDPA with a zinc compound. For
example, a dithiophosphoric acid may be made by reacting mixtures
of primary and secondary alcohols. Alternatively, multiple
dithiophosphoric acids can be prepared where the hydrocarbyl groups
on one are entirely secondary in character and the hydrocarbyl
groups on the others are entirely primary in character. To make the
zinc salt, any basic or neutral zinc compound could be used but the
oxides, hydroxides and carbonates are most generally employed.
Commercial additives frequently contain an excess of zinc due to
the use of an excess of the basic zinc compound in the
neutralization reaction.
[0063] The preferred zinc dihydrocarbyl dithiophosphates are oil
soluble salts of dihydrocarbyl dithiophosphoric acids and may be
represented by the following formula:
##STR00005##
wherein R and R' may be the same or different hydrocarbyl radicals
containing from 1 to 18, preferably 2 to 12, carbon atoms and
including radicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl
and cycloaliphatic radicals. Particularly preferred as R and R'
groups are alkyl groups of 2 to 8 carbon atoms. Thus, the radicals
may, for example, be ethyl, n-propyl, i-propyl, n-butyl, i-butyl,
sec-butyl, amyl, n-hexyl, i-hexyl, n-octyl, decyl, dodecyl,
octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl,
methylcyclopentyl, propenyl, butenyl. In order to obtain oil
solubility, the total number of carbon atoms (i.e. R and R') in the
dithiophosphoric acid will generally be about 5 or greater. The
zinc dihydrocarbyl dithiophosphate can therefore comprise zinc
dialkyl dithiophosphates. The present invention may be particularly
useful when used with lubricant compositions containing phosphorus
levels of from about 0.02 to about 0.12 mass %, such as from about
0.03 to about 0.10 mass %, or from about 0.05 to about 0.08 mass %,
based on the total mass of the composition. In one preferred
embodiment, lubricating oil compositions of the present invention
contain zinc dialkyl dithiophosphate derived predominantly (e.g.,
over 50 mol. %, such as over 60 mol. %) from secondary
alcohols.
[0064] Oxidation inhibitors or antioxidants reduce the tendency of
mineral oils to deteriorate in service. Oxidative deterioration can
be evidenced by sludge in the lubricant, varnish-like deposits on
the metal surfaces, and by viscosity growth. Such oxidation
inhibitors include hindered phenols, alkaline earth metal salts of
alkylphenolthioesters having preferably C.sub.5 to C.sub.12 alkyl
side chains, calcium nonylphenol sulfide, oil soluble phenates and
sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons,
phosphorous esters, metal thiocarbamates, oil soluble copper
compounds as described in U.S. Pat. No. 4,867,890, and
molybdenum-containing compounds.
[0065] Typical oil soluble aromatic amines having at least two
aromatic groups attached directly to one amine nitrogen contain
from 6 to 16 carbon atoms. The amines may contain more than two
aromatic groups. Compounds having a total of at least three
aromatic groups in which two aromatic groups are linked by a
covalent bond or by an atom or group (e.g., an oxygen or sulfur
atom, or a --CO--, --SO.sub.2-- or alkylene group) and two are
directly attached to one amine nitrogen also considered aromatic
amines having at least two aromatic groups attached directly to the
nitrogen. The aromatic rings are typically substituted by one or
more substituents selected from alkyl, cycloalkyl, alkoxy, aryloxy,
acyl, acylamino, hydroxy, and nitro groups.
[0066] Multiple antioxidants are commonly employed in combination.
In one preferred embodiment, lubricating oil compositions of the
present invention contain from about 0.1 to about 1.2 mass % of
aminic antioxidant and from about 0.1 to about 3 mass % of phenolic
antioxidant. In another preferred embodiment, lubricating oil
compositions of the present invention contain from about 0.1 to
about 1.2 mass % of aminic antioxidant, from about 0.1 to about 3
mass % of phenolic antioxidant and a molybdenum compound in an
amount providing the lubricating oil composition from about 10 to
about 1000 ppm of molybdenum.
[0067] Representative examples of suitable viscosity modifiers are
polyisobutylene, copolymers of ethylene and propylene,
polymethacrylates, methacrylate copolymers, copolymers of an
unsaturated dicarboxylic acid and a vinyl compound, interpolymers
of styrene and acrylic esters, and partially hydrogenated
copolymers of styrene/isoprene, styrene/butadiene, and
isoprene/butadiene, as well as the partially hydrogenated
homopolymers of butadiene and isoprene.
[0068] Friction modifiers and fuel economy agents that are
compatible with the other ingredients of the final oil may also be
included. Examples of such materials include glyceryl monoesters of
higher fatty acids, for example, glyceryl mono-oleate; esters of
long chain polycarboxylic acids with diols, for example, the butane
diol ester of a dimerized unsaturated fatty acid; oxazoline
compounds; and alkoxylated alkyl-substituted mono-amines, diamines
and alkyl ether amines, for example, ethoxylated tallow amine and
ethoxylated tallow ether amine.
[0069] Other known friction modifiers comprise oil-soluble
organo-molybdenum compounds. Such organo-molybdenum friction
modifiers also provide antioxidant and antiwear credits to a
lubricating oil composition. Examples of such oil soluble
organo-molybdenum compounds include dithiocarbamates,
dithiophosphates, dithiophosphinates, xanthates, thioxanthates,
sulfides, and the like, and mixtures thereof. Particularly
preferred are molybdenum dithiocarbamates, dialkyldithiophosphates,
alkyl xanthates and alkylthioxanthates.
[0070] Additionally, the molybdenum compound may be an acidic
molybdenum compound. These compounds will react with a basic
nitrogen compound as measured by ASTM test D-664 or D-2896
titration procedure and are typically hexavalent. Included are
molybdic acid, ammonium molybdate, sodium molybdate, potassium
molybdate, and other alkaline metal molybdates and other molybdenum
salts, e.g., hydrogen sodium molybdate, MoOCl.sub.4,
MoO.sub.2Br.sub.2, Mo.sub.2O.sub.3Cl.sub.6, molybdenum trioxide or
similar acidic molybdenum compounds.
[0071] Among the molybdenum compounds useful in the compositions of
this invention are organo-molybdenum compounds of the formulae:
Mo(ROCS.sub.2).sub.4 and
Mo(RSCS.sub.2).sub.4
wherein R is an organo group selected from the group consisting of
alkyl, aryl, aralkyl and alkoxyalkyl, generally of from 1 to 30
carbon atoms, and preferably 2 to 12 carbon atoms and most
preferably alkyl of 2 to 12 carbon atoms. Especially preferred are
the dialkyldithiocarbamates of molybdenum.
[0072] Another group of organo-molybdenum compounds useful in the
lubricating compositions of this invention are trinuclear
molybdenum compounds, especially those of the formula
Mo.sub.3S.sub.kL.sub.nQ.sub.z and mixtures thereof wherein the L
are independently selected ligands having organo groups with a
sufficient number of carbon atoms to render the compound soluble or
dispersible in the oil, n is from 1 to 4, k varies from 4 through
7, Q is selected from the group of neutral electron donating
compounds such as water, amines, alcohols, phosphines, and ethers,
and z ranges from 0 to 5 and includes non-stoichiometric values. At
least 21 total carbon atoms should be present among all the ligand
organo groups, such as at least 25, at least 30, or at least 35
carbon atoms.
[0073] A dispersant-viscosity index improver functions as both a
viscosity index improver and as a dispersant. Examples of
dispersant-viscosity index improvers include reaction products of
amines, for example polyamines, with a hydrocarbyl-substituted
mono- or di-carboxylic acid in which the hydrocarbyl substituent
comprises a chain of sufficient length to impart viscosity index
improving properties to the compounds. In general, the viscosity
index improver dispersant may be, for example, a polymer of a
C.sub.4 to C.sub.24 unsaturated ester of vinyl alcohol or a C.sub.3
to C.sub.10 unsaturated mono-carboxylic acid or a C.sub.4 to
C.sub.10 di-carboxylic acid with an unsaturated nitrogen-containing
monomer having 4 to 20 carbon atoms; a polymer of a C.sub.2 to
C.sub.20 olefin with an unsaturated C.sub.3 to C.sub.10 mono- or
di-carboxylic acid neutralized with an amine, hydroxylamine or an
alcohol; or a polymer of ethylene with a C.sub.3 to C.sub.20 olefin
further reacted either by grafting a C.sub.4 to C.sub.20
unsaturated nitrogen-containing monomer thereon or by grafting an
unsaturated acid onto the polymer backbone and then reacting
carboxylic acid groups of the grafted acid with an amine, hydroxy
amine or alcohol.
[0074] Pour point depressants, otherwise known as lube oil flow
improvers (LOFI), lower the minimum temperature at which the fluid
will flow or can be poured. Such additives are well known. Typical
of those additives that improve the low temperature fluidity of the
fluid are C.sub.8 to C.sub.18 dialkyl fumarate/vinyl acetate
copolymers, and polymethacrylates. Foam control can be provided by
an antifoamant of the polysiloxane type, for example, silicone oil
or polydimethyl siloxane.
[0075] Some of the above-mentioned additives can provide a
multiplicity of effects; thus for example, a single additive may
act as a dispersant-oxidation inhibitor. This approach is well
known and need not be further elaborated herein.
[0076] In the present invention it may also be preferable to
include an additive which maintains the stability of the viscosity
of the blend. Thus, although polar group-containing additives
achieve a suitably low viscosity in the pre-blending stage it has
been observed that some compositions increase in viscosity when
stored for prolonged periods. Additives which are effective in
controlling this viscosity increase include the long chain
hydrocarbons functionalized by reaction with mono- or dicarboxylic
acids or anhydrides which are used in the preparation of the
ashless dispersants as hereinbefore disclosed.
[0077] When lubricating compositions contain one or more of the
above-mentioned additives, each additive is typically blended into
the base oil in an amount that enables the additive to provide its
desired function. Representative effect amounts of such additives,
when used in different lubricants, are listed below. All the values
listed are stated as mass percent active ingredient.
Marine Diesel Cylinder Lubricant ("MDCL")
[0078] A Marine Diesel Cylinder Lubricant may employ 10-35,
preferably 13-30, most preferably 16-24, mass % of a concentrate or
additive package, the remainder being base stock. It preferably
includes at least 50, more preferably at least 60, even more
preferably at least 70, mass % of oil of lubricating viscosity
based on the total mass of MDCL.
[0079] Fully formulated MDCLs preferably have a TBN of at least 20,
such as from about 30 to about 100 mg KOH/g (ASTM D2896). More
preferably, compositions have a TBN of at least 40, such as from
about 40 to about 70 mg KOH/g.
[0080] MDCLs preferably have a sulfated ash (SASH) content (ASTM
D-874) of about 12 mass % or less, preferably about 11 mass % or
less, more preferably about 10 mass % or less, such as 9 mass % or
less.
[0081] The following may be mentioned as examples of typical
proportions of additives in an MDCL:
TABLE-US-00002 Mass % a.i. Mass % a.i. Additive (Broad) (Preferred)
detergent(s) 1-20 3-15 dispersant(s) 0.5-5 1-3 ashless anti-wear
agent(s) 0.1-1.5 0.5-1.3 pour point dispersant 0.03-1.15 0.05-0.1
base stock balance balance
Trunk Piston Engine Oil ("TPEO")
[0082] A Trunk Piston Engine Oil may employ 7-35, preferably 10-28,
more preferably 12-24, mass % of a concentrate or additives
package, the remainder being base stock.
[0083] Fully formulated trunk piston engine oils preferably have a
TBN of at least 10, such as from about 15 to about 60 mg KOH/g
(ASTM D2896). More preferably, compositions have a TBN of at least
20, such as from about 30 to about 55 mg KOH/g.
[0084] Fully formulated trunk piston engine oils preferably have a
sulfated ash (SASH) content (ASTM D-874) of about 7 mass % or less,
preferably about 6.5 mass % or less, such as 6.3 mass % or
less.
[0085] The following may be mentioned as typical proportions of
additives in a TPEO:
TABLE-US-00003 Mass % a.i. Mass % a.i. Additive (Broad) (Preferred)
detergent(s) 0.5-12 2-8 dispersant(s) 0.5-5 1-3 ashless anti-wear
agent(s) 0.1-1.5 0.5-1.3 oxidation inhibitor 0.2-2 0.5-1.5 rust
inhibitor 0.03-0.15 0.05-0.1 pour point dispersant 0.03-1.15
0.05-0.1 base stock balance balance
Crankcase Lubricant
[0086] Fully formulated crankcase lubricating oil compositions
preferably have a TBN of at least 6, such as from about 6 to about
18 mg KOH/g (ASTM D2896). More preferably, compositions have a TBN
of at least 8.5, such as from about 8.5 or 9 to about 18 mg
KOH/g.
[0087] Fully formulated crankcase lubricating oil compositions
preferably have a sulfated ash (SASH) content (ASTM D-874) of about
1.1 mass % or less, preferably about 1.0 mass % or less, more
preferably about 0.8 mass % or less, such as 0.5 mass % or
less.
[0088] The following may be mentioned as examples of typical
proportions of additives in a crankcase lubricant (including
passenger car motor oil and heavy duty diesel motor oil):
TABLE-US-00004 Mass % a.i. Mass % a.i. Additive (Broad) (Preferred)
Metal Detergents 0.1-15 0.2-9 Corrosion Inhibitor 0-5 0-1.5 Metal
Dihydrocarbyl Dithiophosphate 0.1-6 0.1-4 Antioxidant 0-5 0.01-3
Pour Point Depressant 0.01-5 0.01-1.5 Antifoaming Agent 0-5
0.001-0.15 Supplemental Antiwear Agents 0-1.0 0-0.5 Friction
Modifier 0-5 0-1.5 Viscosity Modifier 0.01-10 0.25-3 Basestock
Balance Balance
[0089] Fully formulated lubricating oil compositions of the present
invention preferably have a sulfur content of less than about 0.4
mass %. For crankcase applications, the fully formulated
lubricating oil compositions preferably have a sulfur content of
less than about 0.35 mass % more preferably less than about 0.3
mass %, such as less than about 0.20 mass %. Preferably, the Noack
volatility (ASTM D5880) of the fully formulated lubricating oil
composition (oil of lubricating viscosity plus all additives and
additive diluent) will be no greater than 13, such as no greater
than 12, preferably no greater than 10. Fully formulated
lubricating oil compositions of the present invention preferably
have no greater than 1200 ppm of phosphorus, such as no greater
than 1000 ppm of phosphorus, or no greater than 800 ppm of
phosphorus, such as no greater than 600 ppm of phosphorus, or no
greater than 500 or 400 ppm of phosphorus.
[0090] It may be desirable, although not essential to prepare one
or more additive concentrates comprising additives (concentrates
sometimes being referred to as additive packages) whereby several
additives can be added simultaneously to the oil to form the
lubricating oil composition. A concentration for the preparation of
a lubricating oil composition of the present invention may, for
example, contain from about 0.1 to about 30 mass %, preferably from
0.5 to 30 mass %, of one or more compounds of Formula (I); about 10
to about 40 mass % of a nitrogen-containing dispersant; about 2 to
about 20 mass % of an aminic antioxidant, a phenolic antioxidant, a
molybdenum compound, or a mixture thereof; about 5 to 40 mass % of
a detergent; and from about 2 to about 20 mass % of a metal
dihydrocarbyl dithiophosphate.
[0091] The final composition may employ from 5 to 25 mass %,
preferably 5 to 18 mass %, typically 10 to 15 mass % of the
concentrate, the remainder being oil of lubricating viscosity and
viscosity modifier.
[0092] All weight (and mass) percents expressed herein (unless
otherwise indicated) are based on active ingredient (A.I.) content
of the additive, and/or additive-package, exclusive of any
associated diluent. However, detergents are conventionally formed
in diluent oil, which is not removed from the product, and the TBN
of a detergent is conventionally provided for the active detergent
in the associated diluent oil. Therefore, weight (and mass)
percents, when referring to detergents are (unless otherwise
indicated) total weight (or mass) percent of active ingredient and
associated diluent oil.
[0093] This invention will be further understood by reference to
the following examples, wherein all parts are parts by weight (or
mass), unless otherwise noted.
EXAMPLES
[0094] It is important that the basicity introduced into a
lubricating oil composition be retained as long as possible. It is
also important that the time at which TBN and TAN levels cross is
as long as possible. Both of these measures ensure a longer oil
life and better engine protection over a greater period of
time.
[0095] Beaker tests were performed on three lubricating oil
compositions: a reference oil, Example 1 and Example 2. The
reference oil included 2.475 wt % of an overbased calcium
sulphonate detergent having a TBN of 425 mgKOH/g in base oil.
Example 1 included 2.475 wt % of an overbased calcium sulphonate
detergent having a TBN of 425 mgKOH/g and 1.369 wt % of
poly{[2-hydroxy-5-(tetrapropenyl)-1,3-phenylene]methylene} in base
oil. Example 2 included 2.475 wt % of an overbased calcium
sulphonate detergent having a TBN of 425 mgKOH/g and 1.369 wt % of
poly{[2-hydroxyethoxy-5-(tetrapropenyl)-1,3-phenylene]methylene} in
base oil. All three lubricating oil compositions had a TBN of 10.5
mgKOH/g (ASTM D2896).
[0096] The
poly{[2-hydroxy-5-(tetrapropenyl)-1,3-phenylene]methylene} was
prepared as follows:--
[0097] Para-tetrapropenylphenol (known as `TPP`) (1 mole
equivalent, commerically available), alkylbenzene sulphonic acid
(0.0033 mole % to TPP) and toluene (30 mass % to TPP) were charged
to a baffled reactor equipped with an overhead stirrer and a Dean
and Stark reflux apparatus. A nitrogen blanket was used throughout.
Stirring was increased to 160-170 rpm and the temperature was
ramped up to 110.degree. C. over 40 mins. 36.5% formaldehyde
solution (1.18 equiv. moles of formaldehyde to TPP used) was
charged over 2 hrs at a constant rate. The temperature was
maintained at 110.degree. C. throughout the addition. On completion
of formaldehyde addition, the temperature was increased up to
120.degree. C. and maintained for 1 hr to remove the remaining
water. The reaction was cooled to 90.degree. C., then 50% sodium
hydroxide solution (1.25 moles equiv to alkylbenzene sulphonic
acid) was charged over 0.5 hrs. The temperature was ramped up to
130.degree. C. over 0.5 hrs and maintained for a further 1 hr to
remove water. With apparatus set-up for distillation, the
intermediate was heated up to 130.degree. C. over 1 hr under vacuum
to remove the toluene. Mineral oil was used to cutback product to
50% active ingredient.
[0098] The
poly{[2-hydroxyethoxy-5-(tetrapropenyl)-1,3-phenylene]methylene- }
was prepared as follows:--
[0099] Para-tetrapropenylphenol (known as `TPP`) (1 mole
equivalent, commerically available), alkylbenzene sulphonic acid
(0.0033 mole % to TPP) and toluene (30 mass % to TPP) were charged
to a baffled reactor equipped with an overhead stirrer and a Dean
and Stark reflux apparatus. A nitrogen blanket was used throughout.
The stirring rate was increased to 160-170 rpm. The temperature was
ramped up to 110.degree. C. over 40 mins. 36.5% formaldehyde
solution (1.18 equiv. moles of formaldehyde to TPP used) was
charged over 2 hrs at a constant rate. The temperature was
maintained at 110.degree. C. throughout the addition. On completion
of formaldehyde addition, the temperature was increased up to
120.degree. C. and maintained for 1 hr to remove the remaining
water. The reaction was cooled to 90.degree. C., then 50% sodium
hydroxide solution (2.22 mass % to TPP) was charged over 0.5 hrs.
The temperature was ramped up to 130.degree. C. over 0.5 hrs and
maintained for a further 1 hr to remove water. With apparatus
set-up for distillation, the intermediate was heated up to
130.degree. C. over 1 hr under vacuum to remove the toluene. Xylene
(30 mass % to TPP) was charged whilst cooling down to 90.degree. C.
The Dean and Stark apparatus was switched from distillation to
reflux. Ethylene carbonate (1.02 equivalent moles to TPP) was
charged over 0.5 hrs using a dropping funnel. The temperature was
ramped up to reflux point at 165.degree. C. over 1 hr. IR analysis
was used to determine when ethylene carbonate was fully consumed
(typically after 2.5 hrs). The temperature was maintained at
165.degree. C. and vacuum distillation was used to remove xylene.
Mineral oil was used to cutback product to 50% active
ingredient.
[0100] The Beaker test involved titrating the oil formulation with
1.0M sulphuric acid, and analyzing the TAN and TBN. The flow rate
of acid was 10 ml/hr, the quantity of oil was 250 g, the stirring
rate was 300 rpm and the oil temperature was 95.degree. C.
[0101] After each sample was tested, a centrifuge step was used to
remove insoluble solids before oil analysis.
[0102] The results are as follows:
TABLE-US-00005 Reference Oil Acid Titration TAN TBN (D4739) -
time/h ASTM D664 TBN ASTM D 4739 TAN (D664) 0 0.44 8.8 8.38 0.25
1.73 5.3 3.57 0.5 1.58 4.7 3.12 1 1.56 4.4 2.84 1.5 1.77 4.0 2.23
2.5 1.63 1.6 -0.03
TABLE-US-00006 Example 1 Acid Titration TAN TBN (D4739) - time/h
ASTM D664 TBN ASTM D 4739 TAN (D664) 0 0.71 6.7 5.97 0.25 1.20 6.1
4.9 0.5 1.22 5.1 3.9 1 1.27 4.8 3.5 1.5 1.33 4.0 2.7 2.5 1.30 3.9
2.6
TABLE-US-00007 Example 2 Acid Titration TAN TBN (D4739) - time/h
ASTM D664 TBN ASTM D 4739 TAN (D664) 0 0.40 8.2 7.8 0.25 0.70 5.7
5.00 0.5 0.96 5.5 4.54 1 0.89 5.4 4.51 1.5 0.95 4.4 3.45 2.5 0.97
3.3 2.33
[0103] The results show that the reference oil reaches TAN and TBN
crossover much earlier than Examples 1 and 2. Therefore, the base
in the reference oil is depleted much sooner than the base in
Examples 1 and 2. In fact, Examples 1 and 2 did not show TAN and
TBN crossover even at the end of the test at 2.5 hours. Once
lubricating oil compositions exhibit TAN and TBN crossover, the
composition has insufficient base levels to neutralize any acid
produced by an engine, which causes engine wear. These results are
surprising as Examples 1 and 2 do not include any more base than
the reference oil at the start of the test (i.e. all examples
started the Beaker Test with a TBN of 10.5 mg KOH/g). The results
are also shown graphically in the attached FIG. 1.
* * * * *