FIELD OF THE INVENTION
[0001] The invention is directed to lubricating oil additive concentrates useful in the
formulation of lubricating oil compositions. More specifically, the present invention
is directed to lubricating oil additive concentrates containing at least a basic metal
complex and a surface active agent having at least one hydroxyl or amino group.
BACKGROUND OF THE INVENTION
[0002] Lubricating oil compositions for use in crankcase engine oils comprise a major amount
of base stock oil and minor amounts of additives that improve the performance and
increase the useful life of the lubricant. Crankcase lubricating oil compositions
conventionally contain basic metal complexes, which act as detergents and acid neutralizers,
surface active agents containing at least one hydroxyl or amino group, which function
as organic friction modifiers that are effective in improving fuel economy, and optionally,
polyalkenyl acylating agents, which can act as compatibilizers and/or emulsifiers
that ameliorate unwanted interactions between additives. In the face of increased
demands for improved fuel economy, and further demands for reductions in the amounts
of metal (ash) contained in the lubricant, formulators have used ever-increasing amounts
of organic friction modifiers.
[0003] Lubricating oil additives are commonly provided to lubricant formulators in the form
of 10 to 80 mass %, e.g., 20 to 80 mass % active ingredient (AI) concentrates, which
are then dissolved in major amounts of oil of lubricating viscosity to provide a fully
formulated lubricant. The concentrates are commonly diluted in 3 to 100, e.g., 5 to
40 parts by weight of oil of lubricating viscosity, per part by weight of the additive
concentrate. As noted above, certain lubricating oil additives are known to interact
with others in concentrates. One such known interaction occurs between organic friction
modifiers and overbased metal detergents. Specifically, the organic friction modifiers
have been found to adversely affect the complex of the metal detergents, causing the
formation of sediment in the concentrate upon storage. The presence of a polyalkenyl
acylating agent has been found to regulate this unwanted interaction. However, as
the amount of the organic friction modifier increases to the levels now required,
the effect of the polyalkenyl acylating agent has become insufficient.
[0004] As lubricating oil quality standards have become more stringent, the required amount
of organic friction has increased, and the presence of even minor amounts of sediment
in additive concentrates has become unacceptable to lubricant formulators. Therefore,
it would be advantageous to be able to provide additive concentrates containing overbased
metal detergents and high levels of organic friction modifiers, in which the components
do not interact to form sediment.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to lubricant additive concentrates comprising an
admixture of at least one basic metal complex and at least one surface active agent
having at least one hydroxyl or amino group, in which the basic metal complex is preblended
with a polyalkenyl acylating agent prior to admixture with the surface active agent.
[0006] Other and further objects, advantages and features of the present invention will
be understood by reference to the following specification.
DETAILED DESCRIPTION OF THE INVENTION
[0007] Surface active agents useful in the practice of the invention, also hereinafter referred
to as organic friction modifiers, include oil-soluble compounds containing at least
one polar group selected from hydroxyl and amine groups, which compounds are capable
of reducing friction under hydrodynamic and mixed hydrodynamic/boundary layer conditions.
Examples of such materials include glycerol esters of higher fatty acids, for example,
glycerol 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. Particularly
preferred surface active agents include glycerol oleates, particularly glycerol monooleate,
and ethoxylated amines, particularly ethoxylated tallow amine. Because adverse interactions
are more severe when elevated levels of surface active agent are present in the concentrate,
in a preferred embodiment, the concentrate of the present invention contains at least
3 wt. %, preferably at least 5 wt. %, of surface active agent, based on the total
weight of the additive concentrate. In alternative terms, concentrates that contain
the surface active agent in an amount sufficient to provide a formulated lubricant
with at least 0.5 wt. % of surface active agent after dilution are preferred.
[0008] Basic metal complexes useful in the context of the invention function as both 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. The polar head comprises 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 450 or more.
[0009] 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., barium, 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 450, neutral and overbased calcium phenates and sulfurized phenates
having TBN of from 50 to 450 and neutral and overbased magnesium or calcium salicylates
having a TBN of from 20 to 450. Combinations of detergents, whether overbased or neutral
or both, may be used.
[0010] 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.
[0011] 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 fmal product but typically ranges from about 100 to 220
wt. % (preferably at least 125 wt. %) of that stoichiometrically required.
[0012] 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.
[0013] Carboxylate detergents, e.g., salicylates, can be prepared by reacting an aromatic
carboxylic acid 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. The
aromatic moiety of the aromatic carboxylic acid can contain heteroatoms, such as nitrogen
and oxygen. Preferably, the moiety contains only carbon atoms; more preferably the
moiety contains six or more carbon atoms; for example benzene is a preferred moiety.
The aromatic carboxylic acid may contain one or more aromatic moieties, such as one
or more benzene rings, either fused or connected via alkylene bridges. The carboxylic
moiety may be attached directly or indirectly to the aromatic moiety. Preferably the
carboxylic acid group is attached directly to a carbon atom on the aromatic moiety,
such as a carbon atom on the benzene ring. More preferably, the aromatic moiety also
contains a second functional group, such as a hydroxy group or a sulfonate group,
which can be attached directly or indirectly to a carbon atom on the aromatic moiety.
[0014] Preferred examples of aromatic carboxylic acids are salicylic acids and sulfurized
derivatives thereof, such as hydrocarbyl substituted salicylic acid and derivatives
thereof. Processes for sulfurizing, for example a hydrocarbyl - substituted salicylic
acid, are known to those skilled in the art. Salicylic acids are typically prepared
by carboxylation, for example, by the Kolbe - Schmitt process, of phenoxides, and
in that case, will generally be obtained, normally in a diluent, in admixture with
uncarboxylated phenol.
[0015] Preferred substituents in oil - soluble salicylic acids are alkyl substituents. In
alkyl - substituted salicylic acids, the alkyl groups advantageously contain 5 to
100, preferably 9 to 30, especially 14 to 20, carbon atoms. Where there is more than
one alkyl group, the average number of carbon atoms in all of the alkyl groups is
preferably at least 9 to ensure adequate oil solubility.
[0016] Detergents generally useful in the formulation of lubricating oil compositions also
include "hybrid" detergents formed with mixed surfactant systems, e.g., phenate/salicylates,
sulfonate/phenates, sulfonate/salicylates, and sulfonate/phenate/salicylates, as described,
for example, in pending U.S. Patent Application Nos. 09/180,435 and 09/180,436 and
U.S. Patent Nos. 6,153,565 and 6,281,179.
[0017] Interaction with surface active agents in lubricating additive concentrates is particularly
severe when the metal of the metal complex is calcium. Further, the interaction with
the surface active agent is more pronounced in concentrates containing sulfonate detergents
and complex detergents containing sulfonate surfactant. Therefore, in a preferred
embodiment, the basic metal complex is calcium overbased detergent or overbased sulfonate
or sulfonate-containing complex detergent, more preferably overbased calcium sulfonate
or sulfonate-containing complex detergent.
[0018] Polyalkenyl acylating agents useful in the practice of the invention include polyalkenyl
substituted olefinic mono- and dicarboxylic acid and anhydride producing materials.
Preferred polyalkenyl moieties are derived from α-olefin homopolymers, α -olefin copolymers,
and ethylene-α-olefin copolymers. The α-olefin homo- and copolymers are respectively
polymers of one and of at least two C
3 to C
12 α-olefin(s) having the formula CH
2=CHR', wherein R' is a straight or branched chain alkyl radical comprising 1 to 10
carbon atoms. The unsaturated ethylene-α-olefin copolymers are polymers of ethylene
and at least one α-olefin of the above formula. The α-olefins employed in the foregoing
homo- and copolymers are more preferably selected from the C
3 to C
6 α-olefins of the above formula, R' being a straight or branched chain alkyl of from
1 to 4 carbon atoms. Accordingly, useful α-olefin monomers and comonomers include,
for example, propene, butene-1, hexene-1, octene-1, 4-methylpentene-1, decene-1, dodecene-1,
and mixtures thereof (e.g., mixtures of propene and butene-1). Exemplary of such polymers
are propene homopolymers, butene-1 homopolymers, ethylene-propene copolymers and the
like. A preferred class of polymers are those derived from ethylene and the C
3 and C
4 α-olefins of the above formula; i.e., polyethylene, polypropene, polybutene-1, and
copolymers of ethylene and propene, ethylene and butene-1, butene-1 and propene, and
ethylene and propene and butene-1.
[0019] The polyalkenyl moieties from which the polyalkenyl acylating agent is derived can
have a number average molecular weight in the range of from about 100 to 4000, preferably
from about 450 to 2500, and more preferably from about 750 to 1500. Number average
molecular weight (M
n) can be determined by several known techniques such as gel permeation chromatography
("GPC"), vapor phase osmometry, proton NMR and carbon-13 NMR. Particularly preferred
polyalkenes are polyisobutenes and polybutenes having a number average molecular weight
(M
n) of from about 450 to about 2500, more preferably from about 750 to 1500.
[0020] Mono- and dicarboxylic acid or anhydride producing materials, i.e., acid, anhydride,
or acid ester materials from which the polyalkenyl acylating agents may be derived
include (i) monounsaturated C
4 to C
10 dicarboxylic acid wherein (a) the carboxyl groups are vicinyl, (i.e., located on
adjacent carbon atoms) and (b) at least one, preferably both, of said adjacent carbon
atoms are part of said mono unsaturation; (ii) derivatives of (i) such as anhydrides
or C
1 to C
5 alcohol derived mono- or diesters of (i); (iii) monounsaturated C
3 to C
10 monocarboxylic acid wherein the carbon-carbon double bond is conjugated with the
carboxyl group, i.e., of the structure -C=C-CO-; and (iv) derivatives of (iii) such
as C
1 to C
5 alcohol derived mono- or diesters of (iii). Mixtures of compounds (i) to (iv) may
also be used. Upon reaction with the backbone, the monounsaturation of the reactant
mono- or dicarboxylic acid or anhydride material becomes saturated. Thus, for example,
maleic anhydride becomes backbone-substituted succinic anhydride, and acrylic acid
becomes backbone-substituted propionic acid. Exemplary of such monounsaturated carboxylic
reactants are fumaric acid, itaconic acid, maleic acid, maleic anhydride, chloromaleic
acid, chloromaleic anhydride, acrylic acid, methacrylic acid, crotonic acid, cinnamic
acid, and lower alkyl (e.g., C
1 to C
4 alkyl) acid esters of the foregoing, e.g., methyl maleate, ethyl fumarate, and methyl
fumarate. A particularly preferred mono- or dicarboxylic acid or anhydride material
is maleic anhydride and the preferred polyalkenyl acylating agent is polyisobutenyl
succinic anhydride (PIBSA).
[0021] The polyalkenyl acylating agent and basic metal complex are premixed prior to contact
with the surface active agent containing at least one hydroxyl or amino group. Preferably,
the basic metal complex is premixed with the polyalkenyl acylating agent at an elevated
temperature, such as from about 20 to about 250°C, preferably from about 50 to about
150°C, more preferably from about 75 to about 125°C, for a period of time, such as
from about 0.25 to 24 hours, preferably from about 1 to 10 hours, more preferably
from about 2 to 5 hours.
[0022] The basic metal complex and polyalkenyl acylating agent may be premixed in a wt.
% ratio of basic metal complex to polyalkenyl acylating agent of from about 30:1 to
about 1:30, preferably from about 20:1 to about 0.5:1, such as from about 20:1 to
about 1:1, more preferably from about 10:1 1 to about 4:1.
[0023] The premixed polyalkenyl acylating agent and basic metal complex can be added to
a concentrate containing additives including the hydroxyl or amino group-containing
surface active agent. Alternatively, the premixed polyalkenyl acylating agent and
basic metal complex or polyalkenyl acylated agent-treated basic metal complex, may
be used to form a concentrate containing additives excluding the hydroxyl or amino
group-containing-surface active agent, to which the surface active agent is subsequently
introduced.
[0024] The concentrates of the invention are preferably prepared at an elevated temperature,
i.e. above ambient temperature. Such concentrates may be prepared at a temperature
of at least 50°C such as at least 80°C, preferably at least 90°C, more preferably
at least 100°C. Although energy is saved at low temperatures, practical considerations
dictate the most convenient temperature that can be used. Thus, where any additive
is used that is solid at ambient temperature, it is usually more convenient to raise
the temperature to a temperature at which the additive flows, rather than dissolving
it in oil prior to addition to the other additives. Temperatures of 100°C or more
can be employed if any additive is more conveniently handled at such temperatures.
Consideration must be given to the time for which it is held at the mixing temperature
and its stability under such temperatures and time conditions.
[0025] In order for the concentrate to be oleaginous, the additives may be in solution in
an oleaginous carrier or such a carrier may be provided separately or both. Examples
of suitable carriers are oils of lubricating viscosity, such as described in detail
hereinafter, and aliphatic, naphthenic and aromatic hydrocarbons.
[0026] The components are advantageously held at the mixing temperature for a time sufficient
to achieve a homogenous mixture thereof. This can usually be accomplished within one
half hour, particularly when the temperature of mixing exceeds 80°C.
[0027] The concentrates of the invention can be incorporated into a lubricating oil composition
in any convenient way. Thus, they can be added directly to an oil of lubricating viscosity
by dispersing or dissolving them in the oil at the desired concentrations of the dispersant
and detergent, respectively. Such blending can occur at ambient temperature or elevated
temperatures. Alternatively, the composite can be blended with a suitable oil-soluble
solvent and base oil to form a further concentrate which is then blended with an oil
of lubricating viscosity to obtain the final lubricating oil composition. Such concentrate
will typically contain (on an active ingredient (A.I.) basis) from about 0.5 wt. %
to about 20 wt. %, preferably from about 1 wt. % to about 15 wt. %, more preferably
from about 3 wt. % to about 10 wt. %, of the surface active agent containing at least
one hydroxyl or amino group, and from 3 to 45 wt. %, preferably from 5 to 30 wt. %,
more preferably from about 7.5 wt. % to about 25 wt. % of the premixed polyalkenyl
acylating agent and basic metal complex, based on the concentrate weight; the remainder
of the concentrate comprising diluent (preferably no more than 90 wt. %, such as not
more than 80 wt. %) oil and, optionally, other additives.
[0028] The oil of lubricating viscosity, useful for making concentrates of the invention
or for making lubricating oil compositions therefrom, may be selected from natural
(vegetable, animal or mineral) and synthetic lubricating oils and mixtures thereof.
It may range in viscosity from light distillate mineral oils to heavy lubricating
oils such as gas engine oil, mineral lubricating oil, motor vehicle oil, and heavy
duty diesel oil. Generally, the viscosity of the oil ranges from 2 centistokes to
30 centistokes, especially 5 centistokes to 20 centistokes, at 100°C.
[0029] Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil);
liquid petroleum oils and hydro-refined, 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.
[0030] Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon
oils such as polymerized and interpolymerized olefms (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.
[0031] 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
3-C
8 fatty acid esters and C
13 Oxo acid diester of tetraethylene glycol.
[0032] 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). Examples
of such esters include 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.
[0033] Esters useful as synthetic oils also include those made from C
5 to C
12 monocarboxylic acids and polyols and polyol esters such as neopentyl glycol, trimethylolpropane,
pentaerythritol, dipentaerythritol and tripentaerythritol.
[0034] 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.
[0035] The oil of lubricating viscosity may comprise a Group I, Group II, Group III, Group
IV or Group V oil or blends of the aforementioned oils. The oil of lubricating viscosity
may also comprise a blend of a Group I oil and one or more of Group II, Group III,
Group IV or Group V oil.
[0036] Definitions for the oils as used herein 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 oils as follows:
a) Group I oils 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 oils 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. Although not a separate
Group recognized by the API, Group II oils having a viscosity index greater than about
110 are often referred to as "Group II+" oils.
c) Group III oils 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 oils are polyalphaolefins (PAO).
e) Group V oils are all other base stocks not included in Group I, II, III, or IV.
Table 1
Property |
Test Method |
Saturates |
ASTM D2007 |
Viscosity Index |
ASTM D2270 |
Sulfur |
ASTM D4294 |
[0037] The oil of lubricating viscosity preferably has a saturate content of at least 65%,
more preferably at least 75%, such as at least 85%. Most preferably, the oil of lubricating
viscosity has a saturate content of greater than 90%. Preferably, the oil of lubricating
viscosity has a sulfur content of less than 1%, preferably less than 0.6%, more preferably
less than 0.3%, by mass, such as 0 to 0.3% by mass.
[0038] Preferably the volatility of the oil of lubricating viscosity, as measured by the
Noack test (ASTM D5880), is less than or equal to about 40%, such as less than or
equal to about 35%, preferably less than or equal to about 32%, such as less than
or equal to about 28%, more preferably less than or equal to about 16%. Preferably,
the viscosity index (VI) of the oil of lubricating viscosity is at least 85, preferably
at least 100, most preferably from about 105 to 140.
[0039] In addition to the mixed basic metal complex/polyalkenyl acylating agent and organic
friction modifier, a concentrate, and fully formulated lubricants formed therefrom,
can contain a number of other performance improving additives selected from ashless
dispersants, antiwear agents, oxidation inhibitors or antioxidants, metal-containing
friction modifiers and fuel economy agents, antifoamants and corrosion inhibitors,
including additional amounts of metal detergent and polyalkenyl acylating agent (independent
of the premixed polyalkenyl acylating agent and basic metal complex). Conventionally,
when formulating a lubricant, the additives will be provided to the formulator in
one or more, preferably a single concentrated additive package, oftentimes referred
to as a DI (dispersant-inhibitor) package and a VI improver and/or VI improver and
LOFI, will be provided in a second package.
[0040] Ashless dispersants maintain in suspension oil insolubles resulting from oxidation
of the oil during wear or combustion. They are particularly advantageous for preventing
the precipitation of sludge and the formation of varnish, particularly in gasoline
engines.
[0041] 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 and 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
2S
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.
[0042] 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
5 to C
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. Patent No. 4,867,890,
and molybdenum-containing compounds and aromatic amines.
[0043] Known metal-containing friction modifiers include oil-soluble organo-molybdenum compounds.
Such organo-molybdenum friction modifiers also provide antioxidant and antiwear credits
to a lubricating oil composition. As an example of such oil soluble organo-molybdenum
compounds, there may be mentioned the dithiocarbamates, dithiophosphates, dithiophosphinates,
xanthates, thioxanthates, sulfides, and the like, and mixtures thereof. Particularly
preferred are molybdenum dithiocarbamates, dialkyldithiophosphates, alkyl xanthates
and alkylthioxanthates.
[0044] Foam control can be provided by an antifoamant of the polysiloxane type, for example,
silicone oil or polydimethyl siloxane.
[0045] 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.
[0046] Representative effective amounts of such additional additives, when used in fully
formulated crankcase lubricants, are listed below in Table 2:
Table 2
ADDITIVE |
Mass % (Broad) |
Mass % (Preferred) |
Ashless Dispersant |
0.1-20 |
1-8 |
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 |
0.01-2 |
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 |
Basestock |
Balance |
Balance |
[0047] This invention will be further understood by reference to the following examples,
wherein all parts are parts by weight (AI), unless otherwise noted and which include
preferred embodiments of the invention.
EXAMPLES
[0048] A calcium sulfonate detergent having a TBN of 300 (55 wt. % AI) was treated with
polyisobutenyl succinic anhydride (PIBSA), (PIB M
n of 950; 72 wt. % A.I.), for 3 hours, at a temperature of 100°C, in the amounts shown
in Table 3:
Table 3
Det. No. |
1 |
2 |
3 |
CaSulf Det. |
1.60 |
1.60 |
1.60 |
PIBSA |
0.072 |
0.14 |
0.28 |
Wt. % |
1.672 |
1.74 |
1.88 |
[0049] Concentrates were formed using the above-described premixed PIBSA/detergents, or
1.60 wt. % of the analogous untreated detergent (Det. 4) and other additives normally
provided in a concentrated dispersant inhibitor (DI) package, in the manner described
below:
Dispersant |
1.744 |
1.744 |
1.744 |
1.744 |
1.744 |
1.744 |
1.744 |
Antifoamant |
0.0005 |
0.0005 |
0.0005 |
0.0005 |
0.0005 |
0.0005 |
0.0005 |
Diluent |
3.01 |
3.01 |
3.01 |
3.01 |
3.01 |
3.01 |
3.01 |
blend for 0.5 hours @ 100° C and add |
Det. 4 |
1.60 |
|
|
|
1.60 |
1.60 |
1.60 |
Det. 1 |
|
1.70 |
|
|
|
|
|
Det. 2 |
|
|
1.80 |
|
|
|
|
Det. 3 |
|
|
|
2.00 |
|
|
|
blend for 3 hours @ 100° C and add |
Antioxidant |
1.30 |
1.30 |
1.30 |
1.30 |
1.30 |
1.30 |
1.30 |
Mo-based Antiwear |
0.0045 |
0.0045 |
0.0045 |
0.0045 |
0.0045 |
0.0045 |
0.0045 |
PIBSA |
|
|
|
|
0.072 |
0.14 |
0.28 |
Diluent |
0.0055 |
0.0055 |
0.0055 |
0.0055 |
0.0335 |
0.0655 |
0.1255 |
blend for 1 hour @ 70° C and add |
ZDDP |
0.705 |
0.705 |
0.705 |
0.705 |
0.705 |
0.705 |
0.705 |
Glycerol Monooleate |
0.60 |
0.60 |
0.60 |
0.60 |
0.60 |
0.60 |
0.60 |
Diluent |
0.235 |
0.235 |
0.235 |
0.235 |
0.235 |
0.235 |
0.235 |
and blend for 1 hour @ 60° C. |
Conc. ID |
A |
B |
C |
D |
E |
F |
G |
Treat Rate* |
9.30 |
9.40 |
9.50 |
9.70 |
9.40 |
9.50 |
9.70 |
Inv./Comp |
Comp. |
Inv. |
Inv. |
Inv. |
Comp. |
Comp. |
Comp. |
*recommended amount of concentrate blended with basestock to provide formulated lubricant |
[0050] Each of the above additive concentrates was then subjected to a storage stability
test in which the concentrates were stored for a number of weeks @ 60°C with periodic
measuring of the amount of sediment formed. A concentrate package failed the stability
test at the time the amount of sediment measured was greater than 0.05 wt. %, based
on the total weight of the concentrate. The results are provided in Table 4:
Table 4
Conc. ID |
A |
B |
C |
D |
E |
F |
G |
Week # |
|
|
|
|
|
|
|
1 |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
2 |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
3 |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
Pass |
4 |
Fail |
Pass |
Pass |
Pass |
Fail |
Fail |
Pass |
5 |
Fail |
Pass |
Pass |
Pass |
Fail |
Fail |
Fail |
6 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
7 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
8 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
9 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
10 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
11 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
12 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
13 |
Fail |
Fail |
Pass |
Pass |
Fail |
Fail |
Fail |
[0051] The data demonstrate that the use of a detergent treated with even a low level of
PIBSA (Inventive Conc. B) increased the period for which the concentrate containing
the high level of GMO remained stable from 3 weeks to 5 weeks (a 66% improvement)
compared to the concentrate formed with the untreated detergent (Comparative Conc.
A). Increasing the amount of PIBSA with which the detergent was treated further led
to outstanding stability and Inventive Conc. C and D remained stable after 13 weeks
of storage. A comparison between the Inventive Concentrates (B, C and D) and corresponding
Comparative Concentrates (E, F and G), demonstrates that the presence of PIBSA has
far less of an effect on concentrate stability when the PIBSA is added as a separate
component.
[0052] The disclosures of all patents, articles and other materials described herein are
hereby incorporated, in their entirety, into this specification by reference. A description
of a composition comprising, consisting of, or consisting essentially of multiple
specified components, as presented herein and in the appended claims, should be construed
to also encompass compositions made by admixing said multiple specified components.
The principles, preferred embodiments and modes of operation of the present invention
have been described in the foregoing specification. What applicants submit is their
invention, however, is not to be construed as limited to the particular embodiments
disclosed, since the disclosed embodiments are regarded as illustrative rather than
limiting. Changes may be made by those skilled in the art without departing from the
spirit of the invention.
1. A lubricating oil additive concentrate comprising oil of lubricating viscosity, a
basic metal complex, a polyalkenyl acylating agent, and a surface active agent containing
at least one hydroxyl or amino group, wherein said basic metal complex is premixed
with said polyalkenyl acylating agent prior to incorporation into said concentrate.
2. A concentrate, as claimed in claim 1, wherein said basic metal complex is an overbased
metal detergent.
3. A concentrate, as claimed in claim 2, wherein said overbased metal detergent is selected
from the group consisting of overbased calcium sulfonates, overbased magnesium sulfonates,
overbased calcium phenates, overbased magnesium phenates, overbased calcium carboxylates,
overbased magnesium carboxylates, overbased calcium hybrid detergents containing surfactant
systems comprising at least two of sulfonate, phenate and carboxylate surfactant,
overbased magnesium hybrid detergents containing surfactant systems comprising at
least two of sulfonate, phenate and carboxylate surfactant, and mixtures thereof.
4. A concentrate, as claimed in claim 2, wherein said overbased metal detergent is an
overbased calcium detergent.
5. A concentrate, as claimed in claim 2, wherein said overbased metal detergent is an
overbased metal sulfonate detergent, or an overbased metal hybrid detergent containing
a surfactant system comprising sulfonate surfactant and at least one other surfactants.
6. A concentrate, as claimed in claim 2, wherein said overbased metal detergent is an
overbased calcium sulfonate detergent, or an overbased calcium hybrid detergent containing
a surfactant system comprising sulfonate surfactant and at least one other surfactants.
7. A concentrate, as claimed in any one of the preceding claims, wherein said polyalkenyl
acylating agent is a polyalkenyl substituted mono- or dicarboxylic acid or anhydride
producing material.
8. A concentrate, as claimed in claim 7, wherein said polyalkenyl substituted mono- or
dicarboxylic acid or anhydride producing material is polyisobutenyl succinic anhydride.
9. A concentrate, as claimed in claim 8, wherein said polyisobutenyl succinic anhydride
is derived from polyisobutene having a number average molecular weight of from about
100 to about 4000.
10. A concentrate, as claimed in any one of the preceding claims, wherein said surface
active agent is selected from the group consisting of glycerol esters of higher fatty
acids; esters of long chain polycarboxylic acids with diols; oxazoline compounds;
alkoxylated alkyl-substituted mono-amines, diamines and alkyl ether amines; and mixtures
thereof.
11. A concentrate, as claimed in claim 10, wherein said surface active agent is selected
from the group consisting of glycerol oleates; ethoxylated amines; and mixtures thereof.
12. A concentrate, as claimed in claim 11, wherein said surface active agent is selected
from the group consisting of glycerol mono oleate; ethoxylated tallow amine; and mixtures
thereof.
13. A concentrate, as claimed in any one of the preceding claims, wherein said basic metal
complex and said polyalkenyl acylating agent are premixed in a weight ratio (basic
metal complex to polyalkenyl acylating agent) of from about 30:1 to about 1:30.
14. A concentrate, as claimed in any one of the preceding claims, wherein said basic metal
complex and said polyalkenyl acylating agent are premixed at a temperature of from
about 20°C to about 250°C, for from about 0.25 to 24 hours.
15. A concentrate, as claimed in any one of the preceding claims, containing from about
3 wt. % to about 45 wt. % of the premixed basic metal complex and polyalkenyl acylating
agent; and from about 0.5 wt. % to about 20 wt. % of said surface active agent containing
at least one hydroxyl or amino group; and no more than 90 wt. % oil of lubricating
viscosity; all wt. % being based on the total weight of said concentrate.
16. A concentrate, as claimed in claim 15, further comprising at least one other additive
selected from the group consisting of dispersant, antioxidants and antiwear agents.
17. A concentrate, as claimed in claim 16, further comprising at least one other component
selected from the group consisting of neutral and overbased metal detergents which
have not been premixed with a polyalkenyl acylating agent; and polyalkenyl acylating
agent which has not been premixed with overbased metal detergent.
18. A lubricating oil additive concentrate comprising:
oil of lubricating viscosity;
a premix of an overbased metal detergent selected from the group consisting of overbased
calcium sulfonate detergent; overbased calcium hybrid detergent containing a surfactant
system comprising sulfonate surfactant and at least one other surfactants; and mixtures
thereof; and polyisobutenyl succinic anhydride; and
a surface active agent selected from the group consisting of glycerol oleates; ethoxylated
amines.
19. A concentrate as claimed in claim 18, wherein said overbased metal detergent and said
polyisobutenyl succinic anhydride are premixed in a weight ratio (overbased metal
detergent and said polyisobutenyl succinic anhydride) of from about 10:1 1 to about
4:1.
20. A concentrate, as claimed in claim 18 or 19, wherein said overbased metal detergent
and said polyisobutenyl succinic anhydride are premixed at a temperature of from about
50°C to about 150°C, for from about 1 to 10 hours.
21. A concentrate, as claimed in claim 18, containing from about 5 wt. % to about 30 wt.
% of the premixed overbased metal detergent and polyisobutenyl succinic anhydride;
and from about 3 wt. % to about 10 wt. % of said surface active agent; and no more
than 90 wt. % oil of lubricating viscosity; all wt. % being based on the total weight
of said concentrate.
22. A concentrate, as claimed in any one of claims 18 to 21, further comprising at least
one other additive selected from the group consisting of dispersant, antioxidants
and antiwear agents.
23. A concentrate, as claimed in any one of claims 18 to 22, further comprising at least
one other component selected from the group consisting of neutral and overbased metal
detergents which have not been premixed with a polyalkenyl acylating agent; and polyalkenyl
acylating agent which has not been premixed with overbased metal detergent.
24. A method of forming a stable additive concentrate comprising at least 0.5 wt. % of
a surface active agent selected from the group consisting of glycerol oleates; ethoxylated
amines and mixtures thereof and at least 3.0 wt. % of an overbased metal detergent,
and no more than 90 wt. % of oil of lubricating viscosity which method comprises premixing
said overbased metal detergent with a polyalkenyl acylating agent in a weight ratio
(overbased metal detergent to polyalkenyl acylating agent) of from about 30:1 1 to
about 1:30, to provide a premix; and admixing at least said premix, said surface active
agent and said oil of lubricating viscosity, wherein all wt. % being based on the
total weight of said concentrate.