Note: Descriptions are shown in the official language in which they were submitted.
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LUBRICANTS COMPRISING POLVAROMATIC COMPOUNDS
FIELD OF THE INVENTION
This invention concerns diesel engine lubrication, more specifically trunk
piston diesel engine lubrication using trunk piston engine oil (`TPE0') and
system
lubrication of crosshead (also referred to as two-stroke or slow speed) diesel
engines.
BACKGROUND OF THE INVENTION
Trunk piston diesel engines are used in marine, power generation and rail
traction applications and typically have a rated speed of between 300 and 1000
rpm.
In trunk piston diesel engines a single lubricant composition is used for
crankcase and
cylinder lubrication. All major moving parts of the engine, i.e. the main and
big end
bearings, camshaft and valve gear, are lubricated by a pumped circulation
system.
The cylinder liners are lubricated partially by splash lubrication and
partially by oil
from the circulation system which finds its way to the cylinder wall through
holes in
the piston skirt via the connecting rod and gudgeon pin. Crosshead diesel
engines, on
the other hand, are lubricated using two separate lubricants; the engine
cylinders are
lubricated using a marine diesel cylinder lubricant (or `MDCL'), and the
engine
crankcase is lubricated using a separate lubricant referred to as a system
oil.
Trunk piston diesel engines use a centrifuge system to remove contaminants,
such as for example, soot or water, from the lubricating oil composition.
Similar
centrifuge systems are used to treat the system oil of some crosshead marine
diesel
engines. The centrifuge system relies on the use of a sealing medium that is
heavier
than the lubricating oil composition. The sealing medium is generally water.
When
the lubricating oil composition passes through the centrifuge system, it comes
into
contact with the water. The lubricating oil composition therefore needs to be
capable
of shedding the water and remaining stable in the presence of water. If the
lubricating
oil composition is unable to shed the water, the water builds up in the
lubricating oil
composition forming an emulsion, which leads to deposits building up in the
centrifuge system and prevents the centrifuge system from working properly.
US-AI -2006/0189492 describes certain linked aromatic compounds that act as
soot dispersants in lubricating oil compositions. It does not, however,
describe their
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use in trunk piston or crosshead diesel engine lubrication or the need to be
capable of
shedding water.
SUMMARY OF THE INVENTION
The present invention provides lubrication that improves soot handling and
that is capable of shedding media used in centrifuge systems. The invention
employs
the above-mentioned linked aromatic compounds in combination with nitrogen-
containing ashless dispersant in defined ratios.
In a first aspect, the invention comprises a method of lubricating a trunk
piston
diesel engine, or cross-head diesel engine, having a centrifuge system
including a
sealing medium, the method comprising operation of the engine and lubrication
of the
trunk piston engine or system lubrication of the cross-head engine with a
lubricating
oil composition comprising:
(A) an oil of lubricating viscosity, in a major amount; and
(B) 0.04 to 5 mass %, expressed as active ingredient, of the lubricating
oil
composition, of a combination of:
(B1) at least one linked aromatic compound of the formula:
(r)a (Y')a
Ar¨fL-----Ar)m (II)
wherein:
each Ar independently represents an aromatic moiety having 0 to 3
substituents selected from the group consisting of alkyl, alkoxy,
alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, aryloxy,
aryloxy alkyl, halo and combinations thereof;
each L is independently a linking moiety comprising a carbon-carbon
single bond or a linking group;
each Y' is independently a moiety of the formula Z(0(CR2)õ)yX-,
wherein X is selected from the group consisting of (CR'2)z, 0 and S; R
and R' are each independently selected from H, C1 to C6 alkyl and aryl;
z is Ito 10; n is 0 to 10 when X is (CR'2)z, and 2 to 10 when X is 0 or
S; y is 1 to 30; Z is H, an acyl group, an alkyl group or an aryl group;
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each a is independently 0 to 3, with the proviso that at least one Ar
moiety bears at least one group Y' in which Z is not H; and
m is 1 to 100; and
(B2) at least one nitrogen-containing dispersant, where the mass:
mass ratio of (B1) to (B2) is in the range from 1:3 to 9:1,
preferably in the range from 1:1 to 6:1, such as 3:1 to 6:1.
In a second aspect, the invention comprises a method of enhancing the water-
shedding properties, as measured by a centrifuge water shedding test, of a
lubricating
oil composition in the lubrication of a trunk piston engine, or the system
lubrication of
cross-head diesel engine, having a centrifuge system including a sealing
medium, by
employing a lubricating oil composition as defined in the first aspect of the
invention
when compared with a corresponding lubricating oil composition where (B)
contains
only (B2).
In a third aspect, the invention comprises a trunk piston or cross-head diesel
engine lubricating oil composition having a total base number of at least 15,
such as at
least 20, mg KOH/g, as determined by ASTM D2896, comprising:
(A) at least 40 mass % of an oil lubricating viscosity; and
(B) 0.04 to 5 mass %, expressed as active ingredient, of the lubricating
oil
composition, of a combination of:
(B1) at least one linked aromatic compound of the formula:
(pa (Y')a
Ar¨ÃL _____________________________________ Ar)õ, (II)
wherein:
each Ar independently represents an aromatic moiety having 0 to 3
substituents selected from the group consisting of alkyl, alkoxy,
alkoxyalkyl, hydroxy, hydroxyalkyl, acyloxy, acyloxyalkyl, aryloxy,
aryloxy alkyl, halo and combinations thereof;
each L is independently a linking moiety comprising a carbon-carbon
single bond or a linking group;
each Y' is independently a moiety of the formula Z(0(CR2)n)yX-,
wherein X is selected from the group consisting of (CR'2)z, 0 and S; R
and R' are each independently selected from H, C1 to C6 alkyl and aryl;
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z is 1 to 10; n is 0 to 10 when X is (CR'2)z, and 2 to 10 when X is 0 or
S; y is 1 to 30; Z is H, an acyl group, an alkyl group or an aryl group;
each a is independently 0 to 3, with the proviso that at least one Ar
moiety bears at least one group Y' in which Z is not H; and
m is 1 to 100; and
(B2) at least one nitrogen-containing dispersant, where the mass:
mass ratio of (B1) to (B2) is in the range from 1:3 to 9:1,
preferably in the range from 1:1 to 6:1, such as 3:1 to 6:1.
In this specification, the following words and expressions, if and when used,
have the meanings ascribed below:
"active ingredient" or "(a.i.)" refers to additive material that is not
diluent or
solvent;
"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;
"major amount" means in excess of 50 mass % of a composition;
"minor amount" means less than 50 mass % of a composition;
"TBN" means total base number as measured by ASTM D2896.
Furthermore in this specification:
"phosphorus content" is as measured by ASTM D5185;
"sulphated ash content" is as measured by ASTM D874;
"sulphur content" is as measured by ASTM D2622;
"KV100" means kinematic viscosity at 100 C as measured by ASTM D445.
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.
Further, it is understood that any upper and lower quantity, range and ratio
limits set forth herein may be independently combined.
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DETAILED DESCRIPTION OF THE INVENTION
The features of the invention relating, where appropriate, to each and all
aspects of the invention, will now be described in more detail as follows:
(B1) LINKED AROMATIC COMPOUND
US 2006/0189492 Al describes these compounds which can be prepared from
compounds of formula (I) below.
Cpa (Y)a
Ar¨(- L¨Ar). (I)
wherein each Ar independently represents an aromatic moiety having 0 to 3
substituents selected from the group consisting of alkyl, alkoxy, alkoxyalkyl,
hydroxy,
hydroxyalkyl, halo and combinations thereof; each L is independently a linking
moiety comprising a carbon-carbon single bond or a linking group; each Y is
independently a moiety of the formula H(O(CR2)õ)yX-, wherein X is selected
from the
group consisting of (CR'2)z, 0 and S; R and R' are each independently selected
from
H, C1 to C6 alkyl and aryl; z is Ito 10; n is 0 to 10 when X is (CR'2),, and 2
to 10
when X is 0 or S; and y is 1 to 30; each a is independently 0 to 3, with the
proviso
that at least one Ar moiety bears at least one group Y; and m is 1 to 100.
Aromatic moieties Ar of Formula (I) can be a mononuclear carbocyclic moiety
(phenyl) or a polynuclear carbocyclic moiety. Polynuclear carbocyclic moieties
may
comprise two or more fused rings, each ring having 4 to 10 carbon atoms (e.g.,
naphthalene) or may be linked mononuclear aromatic moieties, such as biphenyl,
or
may comprise linked, fused rings (e.g., binaphthyl). Examples of suitable
polynuclear
carbocyclic aromatic moieties include naphthalene, anthracene, phenanthrene,
cyclopentenophenanthrene, benzanthracene, dibenzanthracene, chrysene, pyrene,
benzpyrene and coronene and dimer, trimer and higher polymers thereof. Ar can
also
represent a mono- or polynuclear heterocyclic moiety. Heterocyclic moieties Ar
include those comprising one or more rings each containing 4 to 10 atoms,
including
one or more hetero atoms selected from N, 0 and S. Examples of suitable
monocyclic heterocyclic aromatic moieties include pyrrole, furan, thiophene,
imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine and purine.
Suitable
polynuclear heterocyclic moieties Ar include, for example, quinoline,
isoquinoline,
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carbazole, dipyridyl, cinnoline, phthalazine, quinazoline, quinoxaline and
phenanthroline. Each aromatic moiety (Ar) may be independently selected such
that
all moieties Ar are the same or different. Polycyclic carbocyclic aromatic
moieties
are preferred. Most preferred are compounds of Formula I wherein each Ar is
naphthalene. Each aromatic moiety Ar may independently be unsubstituted or
substituted with 1 to 3 substituents selected from alkyl, alkoxy alkoxyalkyl,
hydroxyl,
hydroxyalkyl, halo, and combinations thereof. Preferably, each Ar is
unsubstituted
(except for group(s) Y and terminal groups).
Each linking group (L) may be the same or different, and can be a carbon to
carbon single bond between the carbon atoms of adjacent moieties Ar, or a
linking
group. Suitable linking groups include alkylene linkages, ether linkages,
diacyl
linkages, ether-acyl linkages, amino linkages, amido linkages, carbamido
linkages,
urethane linkages, and sulfur linkage. Preferred linking groups are alkylene
linkages
such as -CH3CHC(CH3)2-, or C(CH3)2-; diacyl linkages such as
¨COCO- or -CO(CH2)4C0-; and sulfur linkages, such as -S1- or -Sõ-. More
preferred
linking groups are alkylene linkages, most preferably -CH2-.
Preferably, Ar of Formula (I) represents naphthalene, and more preferably, Ar
is derived from 2-(2-naphthyloxy)-ethanol. Preferably, each Ar is derived from
2-(2-
naphthyloxy)-ethanol, and m is 2 to 25. Preferably, Y of Formula (I) is the
group
H(O(CR2)2)y0-, wherein y is 1 to 6. More preferably, Ar is naphthalene, Y is
HOCH2CH20- and L is -CH2-=
Methods for forming compounds of Formula (I) should be apparent to those
skilled in the art. A hydroxyl aromatic compound, such as naphthol can be
reacted
with an alkylene carbonate (e.g., ethylene carbonate) to provide a compound of
the
formula AR-(Y).. Preferably, the hydroxyl aromatic compound and alkylene
carbonate are reacted in the presence of a base catalyst, such as aqueous
sodium
hydroxide, and at a temperature of from 25 to 300, preferably from 50 to 200,
C.
During the reaction, water may be removed from the reaction mixture by
azeotropic
distillation or other conventional means. If separation of the resulting
intermediate
product is desired, upon completion of the reaction (indicated by the
cessation of CO2
evolution), the reaction product can be collected, and cooled to solidify.
Alternatively,
a hydroxyl aromatic compound, such as naphthol, can be reacted with an
epoxide,
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such as ethylene oxide, propylene oxide, butylenes oxide or styrene oxide,
under
similar conditions to incorporate one or more oxy-alkylene groups.
To form a compound of Formula (1), the resulting intermediate compound Ar-
(Y)a may be further reacted with a polyhalogenated (preferably dihalogenated)
hydrocarbon (e.g., 1-4-dichlorobutane, 2,2-dichloropropane, etc.), or a di- or
poly-
olefin (e.g., butadiene, isoprene, divinylbenzene, 1,4-hexadiene, 1,5-
hexadiene, etc.)
to yield a compound of Formula (I) having an alkylene linking groups. Reaction
of
moieties Ar-(Y)a and a ketone or aldehyde (e.g., formaldehyde, acetone,
benzophenone, acetophenone, etc.) provides an alkylene-linked compound. An
acyl-
linked compound can be formed by reacting moieties Ar-(Y)a with a diacid or
anhydride (e.g., oxalic acid, malonic acid, succinic acid, glutaric acid,
adipic acid,
succinic anhydride, etc.). Sulfide, polysulfide, sulfinyl and sulfonyl
linkages may be
provided by reaction of the moieties Ar-(Y)a with a suitable difunctional
sulfurizing
agent (e.g., sulfur monochloride, sulfur dichloride, thionyl chloride (SOC12),
sulfuryl
chloride (S02C12), etc.). To provide a compound of Formula (I) with an
alkylene
ether linkage, moieties Ar-(Y)a can be reacted with a divinylether. Compounds
of
Formula (1), wherein L is a direct carbon to carbon link, may be formed via
oxidative
coupling polymerization using a mixture of aluminum chloride and cuprous
chloride,
as described, for example, by P. Kovacic, et al., J. Polymer Science: Polymer
Chem.
Ed., 21, 457 (1983). Alternatively, such compounds may be formed by reacting
moieties Ar-(Y)a and an alkali metal as described, for example, in "Catalytic
Benzene
Coupling on Caesiurn/Nanoporous Carbon Catalysts", M.G. Stevens, K.M. Sellers,
S.
Subramoney and H.C. Foley, Chemical Communications, 2679-2680 (1988).
To form the preferred compounds of Formula (I), having an alkylene linking
group, more preferably a methylene linking group, base remaining in the Ar-
(Y)a
reaction mixture can be neutralized with acid, preferably with an excess of
acid (e.g.,
a sulfonic acid) and reacted with an aldehyde, preferably formaldehyde, and
preferably in the presence of residual acid, to provide an alkylene,
preferably
methylene bridged compound of Formula (1). The degree of polymerization of the
compounds of Formula I range from 2 to 101 (corresponding to a value of m of
from
1 to 100), preferably from 2 to 50, most preferably from 2 to 25.
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The compounds of formula (11) can be formed by reacting a compound of
formula (I) with at least one of an acylating agent, an alkylating agent and
an arylating
agent, and are represented by the formula:
(ra (Y')a
Ar--(- L¨Ar)m (11)
wherein each Y' is independently a moiety of the formula Z(0(CR2)õ)yX-; Z is
an acyl
group, an alkyl group or an aryl group or H, and Ar, L, X, R, z, n and y are
the same
as defined in Formula (I), with the proviso that, at least one Ar moiety bears
at least
one substituent group Y' in which Z is not H; and m is 1 to 100.
Suitable acylating agents include hydrocarbyl carbonic acid, hydrocarbyl
carbonic acid halides, hydrocarbyl sulfonic acid and hydrocarbyl sulfonic acid
halides,
hydrocarbyl phosphoric acid and hydrocarbyl phosphoric halides, hydrocarbyl
isocyanates and hydrocarbyl succinic acylating agents. Preferred acylating
agents are
C8 and higher hydrocarbyl isocyanates, such as dodecyl isocyanate and
hexadodecyl
isocyanate and C8 or higher hydrocarbyl acylating agents, more preferably
polybutenyl succinic acylating agents such as polybutenyl, or polyisobutenyl
succinic
anhydride (PIBSA). Preferably the hydrocarbyl succinic acylating agent will
have a
number average molecular weight (Mn) of from 100 to 5000, preferably from 200
to
3000, more preferably from 450 to 2500. Preferred hydrocarbyl isocyanate
acylating
agent will have a number average molecular weight (Mn) of from 100 to 5000,
preferably from 200 to 3000, more preferably from 200 to 2000.
Acylating agents can be prepared by conventional methods known to those
skilled in the art, such as chlorine-assisted, thermal and radical grafting
methods. The
acylating agents can be mono- or polyfunctional. Preferably, the acylating
agents
have a functionality of less than 1.3. Acylating agents are used in the
manufacture of
dispersants, and a more detailed description of methods for forming acylating
agents
is described in the description of suitable dispersants, presented infra.
Suitable alkylating agents include C8 to C30 alkane alcohols, preferably C8 to
C18 alkane alcohols. Suitable arylating agents include C8 to C30, preferably
C8 to C18
alkane-substituted aryl mono- or polyhydroxide.
Molar amounts of the compound of Formula (I) and the acylating, alkylating
and/or arylating agent can be adjusted such that all, or only a portion, such
as 25% or
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more, 50% or more or 75% or more of groups Y are converted to groups Y'. In
the
case where the compound of Formula (I) has hydroxy and/or alkyl hydroxy
substituents, and such compounds are reacted with an acylating group, it is
possible
that all or a portion of such hydroxy and/or alkylhydroxy substituents will be
converted to acyloxy or acyloxy alkyl groups. In the case where the compound
of
Formula (I) has hydroxy and/or alkyl hydroxy substituents, and such compounds
are
reacted with an arylating group, it is possible that all or a portion of such
hydroxy
and/or alkylhydroxy substituents will be converted to aryloxy or aryloxy alkyl
groups.
Therefore, compounds of Formula (II) substituted with acyloxy, acyloxy alkyl,
aryloxy and/or aryloxy alkyl groups are considered within the scope of the
present
invention. A salt form of compounds of Formula (II) in which Z is an acylating
group,
which salts result from neutralization with base (as may occur, for example,
due to
interaction with a metal detergent, either in an additive package or a
formulated
lubricant), is also considered to be within the scope of the invention.
Compounds of Formula (II) can be derived from the precursors of Formula (I)
by reacting the precursors of Formula (I) with the acylating agent, preferably
in the
presence of a liquid acid catalyst, such as sulfonic acid, e.g., dodecyl
benzene sulfonic
acid, paratoluene sulfonic acid or polyphosphoric acid or a solid acid
catalyst such as
TM
Amberlyst-15, Amberlyst-36, zeolites, mineral acid clay or tungsten
polyphosphoric
acid; at a temperature of from about 0 to 300, preferably from 50 to 250, C.
Under
the above conditions, the preferred polybutenyl succinic acylating agents can
form
diesters, acid esters or lactone esters with the compound of Formula (I).
Compounds of Formula (II) can be derived from the precursors of Formula (I)
by reacting the precursors of Formula (I) with the alkylating agent or
arylating agent,
preferably in the presence of triphenylphosphine and diethyl azodicarboxylate
(DEAD), a liquid acid catalyst, such as sulfonic acid, e.g., dodecyl benzene
sulfonic
acid, paratoluene sulfonic acid or polyphosphoric acid or a solid acid
catalyst such as
Amberlyst-1 5, Amberlyst-36, zeolites, mineral acid clay or tungsten
polyphosphoric
acid; at a temperature of from 0 to 300, preferably from 50 to 250, C.
(B2) ASHLESS DISPERSANT
Ashless dispersants useful in the compositions of the present invention
comprise an oil-soluble polymeric long chain backbone having functional groups
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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.
Preferably, the ashless dispersant is a "high molecular weight" dispersant
having a number average molecular weight (Mn) 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
1680 to 5600. Typical commercially-available polyisobutylene-based dispersants
contain polyisobutylene polymers having a number average molecular weight
ranging
from 900 to 2300, functionalized by maleic anhydride (MW = 98), and
derivatized
with polyamines having a molecular weight of from 100 to 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 known in the art.
Polymer molecular weight, specifically number average molecular weight
(M.), can be determined by various known techniques. One convenient method is
gel
permeation chromatography (GPC), which additionally provides molecular weight
distribution information (see W. W. Yau, J. J. Kirkland and D. D. Bly, "Modern
Size
Exclusion Liquid Chromatography", John Wiley and Sons, New York, 1979). If the
molecular weight of an amine-containing dispersant (e.g., PIBSA-polyamine or
PIBSA-PAM) is being determined, the presence of the amine may cause the
dispersant to be adsorbed by the column, leading to an inaccurate molecular
weight
determination. Persons familiar with the operation of GPC equipment understand
that
this problem may be eliminated by using a mixed solvent system, such as
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tetrahydrofuran (THF) mixed with a minor amount of pyridine, as opposed to
pure
THF. The problem may also be addressed by capping the amine with acetic
anhydride and correcting the molecular weight based on the number of capping
groups. Another useful method for determining molecular weight, particularly
for
lower molecular weight polymers, is vapor pressure osmometry (see, e.g., ASTM
D3592).
The degree of polymerization Dp of a polymer is:
D
Mn x mol. /0 monomer i
E 100 x mol.wt monomer i
and thus for the copolymers of two monomers Dp may be calculated as follows:
Mn x mol.% monomer 1 + Mn x moi.% monomer 2
Dp= 100 x mol.wt monomer 1 100 x mol.wt monomer 2
Preferably, the degree of polymerization for the polymer backbones used in
the invention is at least 30, typically from 30 to 165, more preferably 35 to
100.
The preferred hydrocarbons or polymers employed in this invention include
homopolymers, interpolymers or lower molecular weight hydrocarbons. One family
of useful polymers comprise polymers of ethylene and/or at least one C3 to C28
alpha-
olefin having the formula H2C=CHR I , wherein RI 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.
One preferred class of such polymers employed in this invention comprise
interpolymers of ethylene and at least one alpha-olefin of the above formula,
wherein
RI 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, propylene-butene copolymers, ethylene-propylene copolymers,
ethylene-butene-1 copolymers and the like, wherein the polymer contains at
least
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some terminal and/or internal unsaturation. Preferred polymers are unsaturated
copolymers of ethylene and propylene and ethylene and butene-1. The
interpolymers
of this invention may contain a minor amount, e.g. 0.5 to 5 mole % of a C4 to
C18 non-
conjugated diolefin comonomer. However, it is preferred that the polymers of
this
invention 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 in this invention is preferably in
the range
of 20 to 80, more preferably 30 to 70, %. When propylene and/or butene-1 are
employed as comonomer(s) with ethylene, the ethylene content of such
copolymers is
most preferably between 45 and 65 %, although higher or lower ethylene
contents
may be present.
These polymers may be prepared by polymerizing alpha-olefin monomer, or
mixtures of alpha-olefin monomers, or mixtures comprising ethylene and at
least one
C3 to C28 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 Ci3 NMR.
Interpolymers of
this latter type may be characterized by the formula POLY-C(R1)=CH2 wherein RI
is
C1 to C26 alkyl, preferably CI to C18 alkyl, more preferably C1 to C8 alkyl,
and most
preferably CI to C2 alkyl, (e.g., methyl or ethyl) and wherein POLY represents
the
polymer chain. The chain length of the RI 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=CH2, and
a portion of the polymers can contain internal monounsaturation, e.g. POLY-
CH=CH(R1), wherein RI 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. Patent Nos. 5,498,809; 5,663,130; 5,705,577;
5,814,715; 6,022,929 and 6,030,930.
Another useful class of polymers comprises polymers prepared by cationic
polymerization of isobutene, styrene, and the like. Common polymers from this
class
include polyisobutenes obtained by polymerization of a C4 refinery stream
having a
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butene content of 35 to 75% by wt., and an isobutene content of 30 to 60% by
wt., 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
feed streams such as Raffinate II. These feedstocks are disclosed in the art
such as in
U.S. Patent 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 AlC13 or BF3 catalysts). Such polyisobutylenes
generally
contain residual unsaturation in amounts of one ethylenic double bond per
polymer
chain, positioned along the chain.
As noted above, the polyisobutylene polymers employed are generally based
on a hydrocarbon chain of from 900 to 2,300. 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.
Processes for reacting polymeric hydrocarbons with unsaturated carboxylic
acids, anhydrides or esters and the preparation of derivatives from such
compounds
are disclosed in U.S. Patent 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; and GB-A-1,440,219. The polymer or hydrocarbon may be
functionalized,
for example, with carboxylic acid producing moieties (preferably acid or
anhydride)
by reacting the polymer or hydrocarbon under conditions that result in the
addition of
functional moieties or agents, i.e., acid, anhydride, ester moieties, etc.,
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.
When using the free radical grafting process employing a catalyst (e.g.
peroxide), the functionalization is randomly effected along the polymer chain.
Selective functionalization can be accomplished by halogenating, e.g.,
chlorinating or
brominating the unsaturated a-olefin polymer to 1 to 8, preferably 3 to 7, wt.
%
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,
preferably 110
to 160, e.g., 120 to 140, C, for 0.5 to 10, preferably 1 to 7, hours. The
halogenated
polymer or hydrocarbon (hereinafter backbones) can then be reacted with
sufficient
CA 02653107 2009-02-06
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PF2008L003 - 14 -
monounsaturated reactant capable of adding functional moieties to the
backbone, e.g.,
monounsaturated carboxylic reactant, at 100 to 250, usually 180 to 235, C, for
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
can be mixed and heated while adding chlorine to the hot material.
The hydrocarbon or polymer backbone can be functionalized, e.g., with
carboxylic acid producing moieties (preferably acid or anhydride moieties)
selectively
at sites of carbon-to-carbon unsaturation on the polymer or hydrocarbon
chains, or
randomly along chains using the three processes mentioned above, or
combinations
thereof, in any sequence.
The preferred monounsaturated reactants that are used to functionalize the
backbone comprise mono- and dicarboxylic acid material, i.e., acid, anhydride,
or
acid ester material, including (i) monounsaturated C4 to CIO 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 Ci to C5 alcohol
derived
mono- or diesters of (i); (iii) monounsaturated C3 to C10 monocarboxylic acid
wherein
the carbon-carbon double bond is conjugated with the carboxy group, i.e., of
the
structure -C=C-00-; and (iv) derivatives of (iii) such as C1 to C5 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., C1 to C4 alkyl) acid esters of the
foregoing,
e.g., methyl maleate, ethyl fumarate, and methyl fumarate. The monounsaturated
carboxylic reactant, preferably maleic anhydride, typically will be used in an
amount
ranging from 0.01 to 20, preferably 0.5 to 10, wt. %, based on the weight of
the
polymer or hydrocarbon.
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PF2008L003 - 15 -
While chlorination normally helps increase the reactivity of starting olefin
polymers with monounsaturated functionalizing reactant, it is not necessary
with 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, e.g., carboxylic reactant, are contacted at elevated
temperature
to cause an initial thermal "ene" reaction to take place. Ene reactions are
known.
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 100 to 260, preferably 120 to 240, C. Preferably,
free-
radical initiated grafting is accomplished in a mineral lubricating oil
solution
containing, for example, 1 to 50, preferably 5 to 30, wt. % polymer based on
the
initial total oil solution.
The free-radical initiators that may be used are peroxides, hydroperoxides,
and
azo compounds, preferably those that have a boiling point greater than 100 C
and
decompose thermally within the grafting temperature range to provide free-
radicals.
Representative of these free-radical initiators are azobutyronitrile, 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
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 ester or anhydride) 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.
The functionalized oil-soluble polymeric hydrocarbon backbone may then be
further derivatized with a nucleophilic reactant, such as an amine, amino-
alcohol,
alcohol, metal compound, or mixture thereof, to form a corresponding
derivative.
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,
PF2008L003 - 16 -
Useful amine compounds for derivatizing functionalized polymers comprise at
least
one amine and can comprise one or more additional amine or other reactive or
polar
groups. These amines may be hydrocarbyl amines or may be predominantly
hydrocarbyl amines in which the hydrocarbyl group includes other groups, e.g.,
hydroxy groups, alkoxy groups, amide groups, nitrites, imidazoline groups, and
the
like. Particularly useful amine compounds include mono- and polyamines, e.g.,
polyalkene and polyoxyalkylene polyamines of 2 to 60, such as 2 to 40 (e.g., 3
to 20),
total carbon atoms having 1 to 12, such as 3 to 12, preferably 3 to 9,
nitrogen atoms
per molecule. Mixtures of amine compounds may advantageously be used, such as
those prepared by reaction of alkylene dihalide with ammonia. Preferred amines
are
aliphatic saturated amines, including, for example, 1,2-diaminoethane, 1,3-
diaminopropane; 1,4-diaminobutane; 1,6-diaminohexane; polyethylene amines such
as diethylene triamine; triethylene tetramine; tetraethylene pentamine; and
polypropyleneamines such as 1,2-propylene diamine; and di-(1,2-
propylene)triamine.
Other useful amine compounds include: alicyclic diamines such as 1,4-
di(aminomethyl) cyclohexane and heterocyclic nitrogen compounds such as
imidazolines. Another useful class of amines is the polyamido and related
amido-
amines as disclosed in U.S. Patent Nos. 4,857,217; 4,956,107; 4,963,275; and
5,229,022. Also usable is tris(hydroxymethypamino methane (TAM) as described
in
U.S. Patent Nos. 4,102,798; 4,113,639; 4,116,876; and UK 989,409. Dendrimers,
star-like amines, and comb-structured amines may also be used. Similarly, one
may
use condensed amines, as described in U.S. Patent No. 5,053,152. The
functionalized
polymer is reacted with the amine compound using conventional techniques as
described, for example, in U.S. Patent Nos. 4,234,435 and 5,229,022, as well
as in
EP-A-208,560.
The functionalized, oil-soluble polymeric hydrocarbon backbones may also be
derivatized with hydroxy compounds such as monohydric and polyhydric alcohols,
or
with aromatic compounds such as phenols and naphthols. Preferred polyhydric
alcohols include alkylene glycols in which the alkylene radical contains from
2 to 8
carbon atoms. Other useful polyhydric alcohols include glycerol, mono-oleate
of
glycerol, monostearate of glycerol, monomethyl ether of glycerol,
pentaerythritol,
dipentaerythritol, and mixtures thereof. An ester dispersant may also be
derived from
unsaturated alcohols, such as allyl alcohol, cinnamyl alcohol, propargyl
alcohol, 1-
CA 02653107 2009-02-06
PF2008L003 - 17 -
cyclohexene-3-ol, and oleyl alcohol. Still other classes of alcohols capable
of
yielding ashless dispersants comprise ether-alcohols, including oxy-alkylene
and oxy-
arylene. Such ether-alcohols are exemplified by ether-alcohols having up to
150 oxy-
alkylene radicals in which the alkylene radical contains from 1 to 8 carbon
atoms.
The ester dispersants may be di-esters of succinic acids or acid-esters, i.e.,
partially
esterified succinic acids, as well as partially esterified polyhydric alcohols
or phenols,
i.e., esters having free alcohols or phenolic hydroxy radicals. An ester
dispersant may
be prepared by any one of several known methods as described, for example, in
U.S.
Patent No. 3,381,022.
Preferred groups of dispersant include polyamine-derivatized poly a-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 0.3 to 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. Patent No. 3,632,511.
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 1 to 2.5 moles of carbonyl
compound(s) (e.g., formaldehyde and paraformaldehyde) and 0.5 to 2 moles of
polyalkylene polyamine, as disclosed, for example, in U.S. Patent 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
CA 02653107 2009-02-06
,
PF2008L003 - 18 -
be reacted with a compound containing such a polymer substituted on a succinic
anhydride in a manner similar to that described in U.S. Patent No. 3,442,808.
Examples of functionalized and/or derivatized olefin polymers synthesized
using
metallocene catalyst systems are described in the publications identified
supra.
The dispersant can be further post treated by a variety of conventional post
treatments such as boration, as generally taught in U.S. Patent 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
0.1 to 20 atomic proportions of boron for each mole of acylated nitrogen
composition.
Useful dispersants contain from 0.05 to 2.0, e.g., from 0.05 to 0.7, mass %
boron.
The boron, which appears in the product as dehydrated boric acid polymers
(primarily
(HB02)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
0.5 to 4, e.g., from 1 to 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 135 to190, e.g., 140 to 170, C, for
from 1
to 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.
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.
Patent 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.
Patent No.
3,185,704. The reaction product of a nitrogen-containing dispersant and other
suitable capping agents are described in U.S. Patent 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
CA 02653107 2009-02-06
PF2008L003 - 19 -
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.
OIL OF LUBRICATING VISCOSITY (A)
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 2 to 40,
especially
from 4 to 20, centistokes as measured at 100 C.
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.
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
CA 02653107 2009-02-06
PF2008L003 - 20 -
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 C3-
C8 fatty
acid esters and C13 oxo acid diester of tetraethylene glycol.
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.
Esters useful as synthetic oils also include those made from C5 to Cl2
monocarboxylic acids and polyols and polyol esters such as neopentyl glycol,
trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyalkoxy- or
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-ethylhexypsilicate, 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.
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
CA 02653107 2009-02-06
PF20081,003 - 21 -
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.
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.
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:
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.
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.
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.
d) Group IV base stocks are polyalphaolefins (PAO).
e) Group V base stocks include all other base stocks not included
in
Group I, II, III, or IV.
CA 02653107 2009-02-06
PF2008L003 - 22 -
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
(B) ADDITIVE COMBINATION
As stated, the mass: mass ratio of (B1) to (B2) is in the range from 1:3 to
9:1.
Preferably it is in the range of 1:1 to 6:1 more preferably in the range of
3:1 to 6:1.
The respective masses are in terms of active ingredient.
The ratio of (B1) to (B2) may be expressed as the mass % of (B1), as active
ingredient, to the mass % of nitrogen in (B2). For example, in these terms, it
may be
30:1 to 750:1, such as 80:1 to 500:1, for example 250:1 to 500:1; preferably,
it is 40:1
to 80:1.
Also, as stated, additive combination (B) constitutes from 0.04 to 5 mass % of
the lubricating oil composition. Preferably, it constitutes from 0.2 to 2.5,
more
preferably from 0.4 to 2, mass %.
Also, the concentration of (B2) in the lubricating oil composition, expressed
as
the mass % of nitrogen, may be less than 0.03, such as less than 0.02, for
example in
the range of 0.002 to 0.01, such as in the range of 0.004 to 0.005 or to 0.01,
mass %.
CO-ADDITIVES
The lubricating oil composition, to be useful in a trunk piston or cross-head
diesel engine, will contain at least one overbased metal detergent to provide
the
required TBN. Such detergents are well-known and established in the art and
examples include alkali metal or alkaline earth metal additives such as
overbased oil-
soluble or oil-dispersible calcium, magnesium, sodium or barium salts of a
surfactants
selected from phenol, sulphonic acid, carboxylic acid, salicylic acid and
naphthenic
acid, wherein the overbasing is provided by oil-insoluble salts of the metal,
e.g.
carbonate, basic carbonate, acetate, formate, hydroxide or oxalate, which is
stabilised
CA 02653107 2009-02-06
PF2008L003 - 23 -
by the oil-soluble salt of the surfactant. The metal of the oil-soluble
surfactant salt
may be the same or different from that of the metal of the oil-insoluble salt.
Preferably the metal, whether the metal of the oil-soluble salt or oil-
insoluble salt, is
calcium.
The TBN of the detergent may below, i.e. less than 50, medium, i.e. 50-150,
or high, i.e. over 150. Preferably the TBN is medium or high, i.e. more than
50.
More preferably, the TBN is at least 60, more preferably at least 100, more
preferably
at least 150, and up to 500, such as up to 350.
Surfactants for the surfactant system of the overbased detergent preferably
contain at least one hydrocarbyl group, for example, as a substituent on an
aromatic
ring. The term "hydrocarbyl" as used herein means that the group concerned 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. Advantageously, hydrocarbyl groups in
surfactants for
use in accordance with the invention are aliphatic groups, preferably alkyl or
alkylene
groups, especially alkyl groups, which may be linear or branched. The total
number
of carbon atoms in the surfactants should be at least sufficient to impart the
desired
oil-solubility.
Other co-additives that may be used include for example:
Anti-wear additives such as metal (e.g. Zn) salts of dihydrocarbyl
dithiophosphates (e.g. in an amount of from 0.10 to 3.0 mass % of the
lubricating oil
composition); anti-oxidants, or oxidation inhibitors, for example in the form
of
aromatic amines or hindered phenols (e.g. in an amount of up to 3 mass % of
the
lubricating oil composition);
Other additives such as pour point depressants, anti-foamants, metal rust
inhibitors, pour point depressants and/or demulsifiers may be provided, if
necessary.
The terms 'oil-soluble' or 'oil-dispersable' as used herein do not necessarily
indicate that the compounds or additives are soluble, dissolvable, miscible or
capable
of being suspended in the oil in all proportions. These do mean, however, that
they
are, for instance, soluble or stably dispersible in oil to an extent
sufficient to exert
their intended effect in the environment in which the oil is employed.
Moreover, the
CA 02653107 2009-02-06
=
PF20081,003 - 24 -
additional incorporation of other additives may also permit incorporation of
higher
levels of a particular additive, if desired.
The lubricant compositions of this invention comprise defined individual (i.e.
separate) components that may or may not remain the same chemically before and
after mixing.
It may be desirable, although not essential, to prepare one or more additive
packages or concentrates comprising the additives, whereby the additives can
be
added simultaneously to the oil of lubricating viscosity to form the
lubricating oil
composition. Dissolution of the additive package(s) into the lubricating oil
may be
facilitated by solvents and by mixing accompanied with mild heating, but this
is not
essential. The additive package(s) will typically be formulated to contain the
additive(s) in proper amounts to provide the desired concentration, and/or to
carry out
the intended function in the final formulation when the additive package(s)
is/are
combined with a predetermined amount of base lubricant.
Thus, the additives may be admixed with small amounts of base oil or other
compatible solvents together with other desirable additives to form additive
packages
containing active ingredients in an amount, based on the additive package, of,
for
example, from 2.5 to 90, preferably from 5 to 75, most preferably from 8 to
60,
mass % of additives in the appropriate proportions, the remainder being base
oil.
EXAMPLES
This invention will now be described in the following examples which are not
intended to limit the scope of the claims hereof.
SYNTHESIS
Synthesis Example 1
Preparation of a compound of Formula (II):
Step 1 - Preparation of 2-(2-naphthyloxy) ethanol
A two-liter resin kettle equipped with mechanical stirrer, condenser/Dean-
Stark trap, and inlets for nitrogen, was charged with 2-naphthol (600 g, 4.16
moles),
ethylene carbonate (372 g, 4.22 moles) and xylene (200 g), and the mixture was
heated to 90 C under nitrogen. Aqueous sodium hydroxide (50 mass %, 3.0 g) was
added and water was removed by azeotropic distillation at 165 C. The reaction
CA 02653107 2015-05-26
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mixture was kept at 165 C for 2 hours. CO2 evolved as the reaction progressed
and
the reaction was determined to be near completion when the evolution of CO2
ceased.
The product was collected and solidified while cooling to room temperature.
The
completion of reaction was confirmed by FT-IR and HPLC. The structure of the 2-
(2-
naphthyloxy) ethanol product was confirmed by 1H and "C-NMR.
Step 2 - Oligomerization of 2-(2-naphthyloxy) ethanol
A two-liter resin kettle equipped with mechanical stirrer, condenser/Dean-
Stark trap, and inlets for nitrogen, was charged with 2-(2-naphthyloxy)
ethanol from
Step 1, toluene (200 g), SA 117 (60.0 g), and the mixture was heated to 70 C
under
nitrogen. Para-formaldehyde was added over 15 min at 70-80 C, and heated to 90
C
and the reaction mixture was kept at that temperature for 30 min to 1 hour.
The
temperature was gradually increased to 110 C to 120 C over 2-3 hours and water
(75-
83 ml) was removed by azeotropic distillation. The polymer was collected and
solidified while cooling to room temperature. M. was determined by GPC using
polystyrene standard corrected with the elution volume of 2-(2-naphthyloxy)
ethanol
as internal standard. THF was used as eluent. (M. of 1000 dalton). 1H and 13C
NMR
confirmed the structure. FDMS and MALDI-TOF indicates the product contains
mixture of methylene-linked 2-(2-naphthyloxy) ethanol oligomer of Formula (I)
containing from 2 to 24 2-(2-naphthyloxy) ethanol units (m is 1 to 23).
Step 3 - Reaction of methylene-linked 2-(2-naphthyloxy) ethanol oligomer and
an
acylating agent (PIBSA)
A five-liter resin kettle equipped with mechanical stirrer, condenser/Dean-
Stark trap, inlets for nitrogen, and additional funnel was charged with poly
(2-(2-
naphthyloxy) ethanol)-co-formaldehyde) from Step 2, toluene (200 g), and the
mixture is heated to 120 C under nitrogen. Polyisobutenyl succinic anhydride
(PIBSA M. of 450, 2,500 g) was added portion wise (-250 g at 30 min intervals)
and
the temperature was maintained at 120 C for 2 hours followed by heating to
140 C
under nitrogen purge for an additional 2 hours to strip off all solvents to a
constant
Tis,1
weight. Base oil (AMEXOM 100 N, 1100 g) was added, and the product was
collected at room temperature. GPC and FT-IR confirmed the desired structure.
The reaction scheme representing the above synthesis is shown below:
CA 02653107 2015-05-26
- 26 -
(),lIB
OH
/
/OH
0----
0/
Ethylene Carbonate
1111
+113SA 0"-.
1111
____________________________ ===
n
AO
5
IW 1110
TESTING AND RESULTS
The following examples use a centrifuge water shedding test which evaluates
the ability of an oil to shed water from a prepared test mixture of oil and
water. The
TN1
10 test uses an Alfa Laval MAB103B 2.0 centrifuge coupled to a Watson
Marlow TM
peristaltic pump. The centrifuge is sealed with 800 ml of water. A measurement
is
made of the amount of deposits formed in the centrifuge during the test. Pre-
measured amounts of water and the test oil are mixed together and then passed
through the centrifuge at a rate of 2 litres/min. The test is run for an hour
and a half,
allowing the mixture to pass through the centrifuge about 10 times. The
centrifuge is
weighed before and after the test. A poor trunk piston diesel engine lubricant
will
produce a larger amount of deposits in the centrifuge system.
A set of lubricant formulations was tested as set forth in the table below.
Reference Examples A, B and C are for comparison purposes. Example 1 is an
example of the invention. The key to the table is as follows:
,
PIBSA/PAM: a polyisobutenyl succinic anhydride/polyamine dispersant.
PmNE: the final product of Synthesis Example 1 above.
Each formulation comprised a Group 11 base oil and a Group 1 bright stock, a
zinc dihydrocarbyl dithiophosphatc antiwear additive, and a detergent system
in the
form of a 225 TBN calcium salicylate and a 350 TBN calcium salicylate in the
ratio
(mass : mass) of 1.419:1. Additionally, each formulation contained one or both
of a
PlBSA/PAM and the PmNE in the amounts (mass %) given in the table below;
otherwise the formulations are equivalent.
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PF2008L003 - 27 -
EXAMPLE PtnNE PIBSA/PAM TOTAL MASS OF
(active (mass % N)
DEPOSITS MEASURED (g)
ingredient)
Reference A 0.012* 140
Reference B 0.4 72
Reference C 0.00426** 35
1 0.32 0.00426** 45
corresponds to 0.6 mass % active ingredient
** corresponds to 0.1 mass % active ingredient
Reference Example C contains a low total proportion of dispersant and
therefore exhibits a good water shedding result as demonstrated by the low
mass of
deposits. Reference Example C, however, would exhibit poor soot handling
properties because of its low total proportion of dispersant.
Reference Examples A and B, respectively containing PIBSA/PAM and
PmNE as sole dispersants and, for Reference Example A, in a higher proportion
than
in Reference Example C, exhibit poor water shedding properties.
Example 1, of the invention, contains both PIBSA/PAM and PmNE and
exhibits much better water shedding performance than Reference Examples A and
B
at the same total dispersant treat rate. Also, because of its higher total
dispersant treat
rate, Example 1 would exhibit much better soot handling properties than
Reference
Example C.
