Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
LUBRICATING COMPOSITION COMPRISING A DISPERSANT, AN
ANTIOXIDANT, AND A CORROSION INHIBITOR
FIELD OF INVENTION
The present invention relates to a lubricating composition containing a
dispersant, a corrosion inhibitor and an antioxidant. The invention further
provides a method for lubricating a mechanical device, typically requiring a
working fluid, a hydraulic fluid, a circulating oil or a turbine oil, with the
lubricating composition.
BACKGROUND OF THE INVENTION
[0001] Ash-containing and ashless lubricating compositions are utilised in
various mechanical devices (for example stationary or mobile machinery
requiring a working fluid, a hydraulic fluid, a circulating oil or a turbine
oil).
The lubricating compositions often operate under high temperatures and/or high
pressure regimes in the mechanical device. The high temperatures and/or high
pressure regimes are believed to decompose additives in the lubricating
composition that are less thermally and/or oxidatively stable. Typically
additives that tend to decompose are often ash-containing additives that
contain
a metal. Furthermore, as ash-containing additives decompose, divalent metals
such as zinc, calcium or magnesium, are released into the lubricating
composition. The divalent metals are then capable of reacting with other
performance additives present in the lubricating composition, such as alkenyl
succinic anhydrides and alkenyl succinimides creating sludge and other
particulate matter that can cause filter plugging.
[0002] In an attempt to overcome the difficulties associated with
lubricating
a mechanical device with ash-containing lubricating compositions, ashless
formulations have been contemplated. However, the formulation of an ashless
lubricating composition suitable for a mechanical device may be difficult and
many compositions are believed to have at least one of limited oxidative
stability, limited thermal stability, filter plugging, and produce
unacceptable
levels of sludge.
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[0003] EP 0 821 053 A2 discloses a synergistic antioxidant composition
composed of amine salts of alkyl phosphates and ethylene diamine, ammonium
or metal salts of alkylarylsulphonates. The antioxidant composition is useful
for zinc-free antiwear hydraulic fluids.
[0004] International Application WO 00/11122 discloses lubricating
compositions containing (I) 100 pbw of a base oil, (II) an antiwear agent
comprising (i) from 0.05 to 10 pbw of a phosphorothionate and from 0.01 to 1.0
pbw of an amine salt of phosphorus compound and/or (ii) from 0.05 to 10 pbw
of a dithiophosphate, and (III) a rust preventing agent comprising from 0.01
to
1.0 pbw of an amide obtained by reacting a polyalkylene polyamine and a
carboxylic acid having from 4 to 30 carbon atoms. The lubricating composition
is suitable for hydraulic systems.
[0005] US Patent 5,922657 discloses a hydraulic fluid containing a base
oil
selected from mineral, vegetable and synthetic oils, 13-dithiophosphorylated
propionic acid, and at least one oil additive from the group consisting of
antioxidants, metal passivators, rust inhibitors, dispersants, detergents,
viscosity index improvers, pour point depressants, antifoams, solid lubricants
and further antiwear agents.
[0006] US Patent Application 2002/0010103 Al discloses industrial oils
such as hydraulic oils containing (a) at least one a compound selected from
the
group consisting of a phosphoric acid ester, a thiophosphoric acid ester, and
amine salts thereof; (b) at least one of a phosphorus acid ester and/or an
amine
salt thereof; and (c) at least one compound selected from the group consisting
of an alkenyl succinimide, an alkenyl succinic acid ester, benzylamine, and
derivatives thereof
[0007] International Application WO 04/113479 discloses industrial fluids
containing (1) an antiwear package comprising: (a) a hydrocarbyl phosphate
and amine salt thereof; and (b) an alkylene coupled adduct of a hydrocarbyl
substituted dithiophosphoric acid and a a,I3-unsaturated carbonyl containing
compound; (2) an antioxidant package comprising: (a) a hydrocarbyl
diphenylamine; and (b) a sterically hindered phenol; (3) a metal deactivator;
and (4) an oil of lubricating viscosity.
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[0008] Hence it would be desirable to discover a lubricating composition
suitable for a mechanical device capable of reducing or minimising at least
one
of filter plugging, limited oxidative stability, limited thermal stability,
and
produce unacceptable levels of sludge. The present invention provides a
lubricating composition and method of lubricating a mechanical device capable
of reducing or minimising at least one of filter plugging, limited oxidative
stability, limited thermal stability, and produce unacceptable levels of
sludge.
SUMMARY OF THE INVENTION
[0009] In one embodiment the invention provides an ashless lubricating
composition comprising:
(a) a dispersant;
(b) an antioxidant;
(c) a corrosion inhibitor; and
(d) an oil of lubricating viscosity.
[0010] In one embodiment the invention provides a method for lubricating
a
mechanical device (typically requiring a working fluid, a hydraulic fluid, a
circulating oil or a turbine oil) comprising supplying to the mechanical
device
an ashless lubricating composition comprising:
(a) a dispersant;
(b) an antioxidant;
(c) a corrosion inhibitor; and
(d) an oil of lubricating viscosity.
[0011] In one embodiment the invention provides an ashless lubricating
composition comprising:
(a) about 0.01 to about 2 wt % of a dispersant;
(b) about 0.01 to about 2 wt % of an antioxidant;
(c) about 0.0001 wt % to about 0.1 wt % of a corrosion inhibitor; and
(d) an oil of lubricating viscosity.
[0012] In one embodiment the invention provides a method for lubricating
a
mechanical device (typically requiring a working fluid, a hydraulic fluid, a
circulating oil or a turbine oil) comprising supplying to the mechanical
device
an ashless lubricating composition comprising:
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(a) about 0.01 to about 2 wt % of a dispersant;
(b) about 0.01 to about 2 wt % of an antioxidant;
(c) about 0.0001 wt % to about 0.1 wt % of a corrosion inhibitor; and
(d) an oil of lubricating viscosity.
[0013] In one embodiment the ashless lubricating compositions disclosed
above further comprises an antiwear agent. In one embodiment the ashless
lubricating compositions disclosed above further contain about 0.05 wt % to
about 1.5 wt % of an antiwear agent.
[0014] In one embodiment the invention provides the ashless lubricating
compositions disclosed above in the form of a concentrate.
DETAILED DESCRIPTION OF THE INVENTION
[0015] The present invention provides an ashless lubricating composition
and a method for lubricating a mechanical device as disclosed above.
[0016] As used herein the term "ashless" means that the lubricating
composition and/or additives discussed below are substantially-free of metal.
Substantially-free of means the composition will contain ash-forming materials
(e.g., a metal, typically a divalent metal such as zinc, calcium or magnesium)
at
less than about 150 ppm, or less than about 100 ppm, or about 10 ppm or less,
or less than about 1 ppm. Typically, the ash-forming materials will be present
only in trace amounts, normally associated with contaminants.
Dispersant
[0017] A suitable dispersant includes a succinimide dispersant (for
example
N-substituted long chain alkenyl succinimides), a Mannich dispersant, an ester-
containing dispersant, a condensation product of a fatty hydrocarbyl
monocarboxylic acylating agent with an amine or ammonia, an alkyl amino
phenol dispersant, a hydrocarbyl-amine dispersant, a polyether dispersant, or
a
polyetheramine dispersant. In different embodiments the dispersant includes a
succinimide dispersant, succinic acid ester dispersant, or Mannich dispersant.
[0018] In different embodiments the succinimide dispersant contains an
average of at least about 8, or about 30, or about 35 up to about 350, or to
about
200, or to about 100 carbon atoms. In one embodiment, the long chain alkenyl
group is derived from a polyalkene characterised by an ¨Mn (number average
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molecular weight) of at least 500. Generally, the polyalkene is characterised
by
_
an Mn of about 500, or about 700, (or about 800, or even about 900) to about
5000, (or to about 2500, or to about 2000, or to about 1500, or to about
1200).
In one embodiment the long chain alkenyl group includes those derived from
polyolefins. The polyolefins may be derived from monomers including mono-
olefins having about 2 to about 10 carbon atoms, such as ethylene, propylene,
1-butene, isobutylene, and 1-decene. An especially useful monoolefin source is
a C4 refinery stream having about 35 to about 75 weight percent butene content
and about 30 to about 60 weight percent isobutene content. Useful polyolefins
include polyisobutylenes having a number average molecular weight of about
400 to about 5000, or about 400 to about 2500, or about 400, or about 500 to
about 1500. The polyisobutylene vinylidene double bond content in different
embodiments includes the ranges of about 5 % to about 69 %, or about 50 % to
about 69 %, or about 50 % to about 95 %.
[0019] In one embodiment the succinimide dispersant comprises a
polyisobutylene succinimide, wherein the polyisobutylene has a number
average molecular weight of about 400 to about 5000.
[0020]
Succinimide dispersants and their methods of preparation are more
fully described in U.S. Patents 4,234,435 and 3,172,892.
[0021]
Suitable amines include mono amines or polyamines (for example
ethylenediamine, diethylenetriamine,
triethylenetetramine,
pentaethylenehexamine, or still bottoms (commercially available from Dow as
HPAXO)). The hydrocarbyl-substituted amine may be formed by heating a
mixture of a chlorinated olefin or polyolefin such as a chlorinated
polyisobutyl-
ene with an amine such as ethylenediamine in the presence of a base such as
sodium carbonate as described in U.S. Patent No. 5,407,453.
[0022] The
dispersants may also be post-treated by conventional methods by
a reaction with any of a variety of agents. Among these are boron-containing
compounds, urea, thiourea, dimercaptothiadiazoles, carbon disulphide,
aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic
anhydrides, maleic anhydride, nitriles, epoxides, phosphorus compounds and/or
metal compounds. In one embodiment the dispersant is a borated dispersant.
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Typically the borated dispersant is derived from a succinimide dispersant
comprising a polyisobutylene succinimide, wherein the polyisobutylene has a
number average molecular weight of 400 to 5000.
[0023] A
borated succinimide dispersant may be prepared using a borating
agent. The borating agent includes various forms of boric acid (including
metaboric
acid, HB02, orthoboric acid, H3B03, and tetraboric acid, H2B407), boric oxide,
boron
trioxide, and alkyl borates, such as those of the formula (RO)xB(OH)y wherein
x is
about 1 to about 3 and y is about 0 to about 2, the sum of x and y being 3,
and where R
is an alkyl group containing about 1 to about 6 carbon atoms. In one
embodiment,
the boron compound is an alkali or mixed alkali metal and alkaline earth metal
borate. These metal borates are generally hydrated particulate metal borates
which are known in the art. In one embodiment the metal borates include
mixed alkali and alkaline earth metal borates. The metal borates are available
commercially.
[0024] In
different embodiments the dispersant is present in ranges
including about 0.001 wt % to about 5 wt %, or about 0.005 to about 2.5 wt %,
about 0.05 to about 1.5 wt %, or about 0.08 to about 0.8 wt % of the
lubricating
composition.
Antioxidant
[0025] The
antioxidant of the invention includes sulphurised olefins,
sulphides such as tert-nonyl mercaptan reacted with propylene oxide (mole
ratio 1:1), a hindered phenol, or aminic compounds such as
phenylalphanaphthylamine or an alkylated diphenylamine.
[0026]
Examples of a suitable hindered phenol include 2,6-di-tert-buty1-4-
methylphenol, 3-(3,5-di-tert-buty1-4-hydroxy-pheny1)-propionic acid butyl
ester, 3-(3,5-di-tert-butyl-4-hydroxy-phenyl)-propionic acid isooctyl ester or
3-
(3,5-di-tert-buty1-4-hydroxy-pheny1)-propionic acid 2-ethylhexyl ester), 2,6-
di-
tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethy1-
2,6-di-tert-
butylphenol, 4 -propy1-2 ,6 -di-tert-butylp henol, 4-butyl-2,6-di-tert-
butylphenol
4-penty1-2-6-di-tert-butylphenol, 4-hexy1-2,6-di-tert-butylphenol, 4-hepty1-
2,6-
di-tert-butylphenol, 4-(2-ethylhexyl)-2,6-di-tert-butylphenol, 4-octy1-2,6-di-
tert-butylphenol, 4-nony1-2,6-di-tert-butylphenol, 4-decy1-
2,6-di-tert-
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butylphenol, 4-undecy1-2,6-di-tert-butylphenol, 4-do
decy1-2,6-di-tert-
butylphenol, 4-tridecy1-2,6-di-tert-
butylphenol, 4-tetradecy1-2,6-di-tert-
butylphenol, or mixtures thereof.
[0027]
Examples of a suitable methylene-bridged sterically hindered phenol
include 4,4 '-methylenebis(6-tert-butyl-
o-cresol), 4,4' -methylenebis(2-tert-
amyl-o-cresol), 2,2'-methylenebis(4-methy1-6-tert-butylphenol), 4,4'-
methylene-bis(2,6-di-tertbutylphenol), or mixtures thereof.
[0028] Examples of a suitable aminic compound include nonyl
diphenylamine, di-nonyl diphenylamine, octyl diphenylamine, di-octyl
diphenylamine, butyl octyl diphenylamine, octyl styrenyl diphenylamine or
diethyl dinonyl diphenylamine.
[0029] In one
embodiment the antioxidant includes (i) a hindered phenol or
(ii) an alkylated diphenylamine. In one embodiment the antioxidant includes a
mixture of a hindered phenol and an alkylated diphenylamine.
[0030] In
different embodiments the antioxidant is present in ranges
including about 0.01 to about 3 wt %, or about 0.01 to about 2 wt %, or about
0.05 to about 1 wt % of the lubricating composition.
Corrosion Inhibitor
[0031] The
corrosion inhibitor may also be described as a metal deactivator
or a yellow-metal passivator.
[0032] Examples of a corrosion inhibitor include benzotriazoles,
1,2,4-triazoles, benzimidazoles, 2-
alkyldithiobenzimidazoles,
2-alkyldithiobenzothiazoles, 2-(N,N-
dialkyldithiocarbamoyl)benzothiazoles,
2,5 -bis(alkyl-dithio)-1,3 ,4 -thiadiazoles, 2,5 -bis(N,N-dialkyldithio
carbamoy1)-
1,3,4-thiadiazoles, 2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof
In one embodiment the corrosion inhibitor includes a benzotriazole. In one
embodiment the corrosion inhibitor includes a 2,5-bis(alkyl-dithio)-1,3,4-
thiadiazo le.
[0033]
Benzotriazoles include those containing hydrocarbyl substitutions on
at least one of the following ring positions 1- or 2- or 4- or 5- or 6- or 7-.
The
hydrocarbyl groups in different embodiments contain 1 to about 30, or 1 to
about 15, or 1 to about 16 carbon atoms. In one embodiment the corrosion
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inhibitor includes tolyltriazo le. In one embodiment hydrocarbyl
benzotriazoles
substituted at positions 4- or 5- or 6- or 7- are further reacted with an
aldehyde
and an amine.
[0034]
Examples of suitable hydrocarbyl benzotriazoles further reacted with
an aldehyde and an amine include N,N-bis(2-ethylhexyl)-ar-methy1-1H-
benzotriazole- 1 -methanamine, N,N-
bis(2-ethylhexyl)-4-methyl- 1 H-
benzotriazole- 1 -methanamine, N,N-
bis(2-ethylhexyl)-4-methyl- 1 H-
benzotriazole- 1 -methanamine, 2H-benzotriazole-2-methanamine, N-(4-
methoxypheny1)- 1 H-benzotriazole- 1 -methanamine, N,N-
dido decyl- 1 H-
benzotriazole- 1 -methanamine, N-( 1 H-
benzotriazol- 1 -ylmethyl)-N-(2-
ethylhexyl)- 1 H-benzotriazole- 1 -methanamine, N-
methyl-N-phenyl- 1 H-
benzotriazole- 1 -methanamine, 4,5
,6,7-tetrahydro-N,N-ditridecyl- 1 H-
benzotriazole- 1 -methanamine, N,N-
dioctadecyl- 1 H-benzotriazole- 1 -
methanamine, 5 -methyl-N,N-dioctyl- 1 H-b enzotriazo le- 1 -methanamine, N ,N-
dibutyl- 1 H-benzotriazole- 1 -methanamine, N-(4-
methylpheny1)- 1 H-
benzotriazole- 1 -methanamine, N,N-
bis(2-ethylhexyl)- 1 H-benzotriazole- 1 -
methanamine, N,N-diocty1-2H-benzotriazole-2-methanamine, N-dodecy1-1H-
benzotriazole- 1 -methanamine, N-
phenyl- 1 H-benzotriazole- 1 -methanamine,
N,N-didodecy1-4,5 ,6,7-tetrahydro- 1 H-b enzotriazole- 1 -methanamine, N,N-
bis(2-ethylhexyl)-5 -methyl-1 H-b enzotriazo le- 1 -methanamine, N-octadecyl-
1 H-
benzotriazole- 1 -methanamine, N,N-
didodecy1-2H-benzotriazole-2-
methanamine, N,N-diocty1-1H-benzotriazole-l-methanamine, N-(2-ethylhexyl)-
1 H-benzotriazo le- 1 -methanamine, 4,5
,6,7-tetrahydro-N,N-ditetradecyl- 1 H-
benzotriazole-l-methanamine, or mixtures thereof. In one embodiment the
corrosion inhibitor includes N,N-bis(2-ethylhexyl)-4-methy1-1H-benzotriazole-
1 -methanamine or N,N-
bis(2-ethylhexyl)-ar-methyl- 1 H-benzotriazole- 1 -
methanamine.
[0035] In one
embodiment, the corrosion inhibitor includes (i) a 2,5-
bis(alkyl-dithio)-1,3,4-thiadiazole, (ii) a benzotriazole containing a
hydrocarbyl
substitution on at least one of the following ring positions 4- or 5- or 6- or
7-,
or (iii) a benzotriazole containing a hydrocarbyl substitution (typically a
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benzotriazole further reacted with an aldehyde and an amine) at least one of
the
following ring positions 1- or 2-.
[0036] In one
embodiment, the corrosion inhibitor includes 2,5-bis(alkyl-
dithio)-1,3,4-thiadiazoles. In different embodiments the alkyl groups of 2,5-
bis(alkyl-dithio)-1,3,4-thiadiazoles contain 1 to about 30, or about 2 to
about
25, or 4 to about 20, or about 6 to about 16 carbon atoms. Examples of
suitable
2,5 -bis(alkyl-dithio)-1,3 ,4-thiadiazoles include 2,5 -bis(tert-o ctyldithio)-
1,3 ,4-
thiadiazo le, 2,5 -bis(tert-nonyldithio)-1,3 ,4-thiadiazole, 2,5 -
bis(tert-
decyldithio)-1,3,4-thiadiazole, 2,5 -
bis(tert-undecyldithio)-1,3 ,4-thiadiazole,
2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole, or mixtures thereof.
[0037] The
corrosion inhibitor may be used alone or in combination with
two, three or more corrosion inhibitors. In one embodiment the corrosion
inhibitor includes a mixture of (i) a 2,5-bis(alkyl-dithio)-1,3,4-thiadiazole,
(ii) a
benzotriazole containing a hydrocarbyl substitution on at least one of the
following ring positions 4- or 5- or 6- or 7-, and (iii) a benzotriazole
containing
a hydrocarbyl substitution (typically a benzotriazole further reacted with an
aldehyde and an amine) on at least one of the following ring positions, 1- or
2-.
[0038] In
different embodiments the corrosion inhibitor is present in ranges
including about 0.0001 wt % to about 5 wt %, or about 0.0001 wt % to about
0.5 wt %, or about 0.0001 wt % to about 0.1 wt %, or about 0.0005 wt % to
about 0.06 wt % of the lubricating composition.
Oils of Lubricating Viscosity
[0039] The
lubricating composition comprises an oil of lubricating
viscosity. Such oils include natural and synthetic oils, oil derived from
hydrocracking, hydrogenation, and hydrofinishing, unrefined, refined and re-
refined oils and mixtures thereof.
[0040]
Unrefined oils are those obtained directly from a natural or synthetic
source generally without (or with little) further purification treatment.
[0041] Refined
oils are similar to the unrefined oils except they have been
further treated in one or more purification steps to improve one or more
properties. Purification techniques are known in the art and include solvent
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extraction, secondary distillation, acid or base extraction, filtration,
percolation
and the like.
[0042] Re-refined oils are also known as reclaimed or reprocessed oils,
and
are obtained by processes similar to those used to obtain refined oils and
often
are additionally processed by techniques directed to removal of spent
additives
and oil breakdown products.
[0043] Natural oils useful in making the inventive lubricants include
animal
oils, vegetable oils (e.g., castor oil, lard oil), mineral lubricating oils
such as
liquid petroleum oils and solvent-treated or acid-treated mineral lubricating
oils
of the paraffinic, naphthenic or mixed paraffinic-naphthenic types and oils
derived from coal or shale or mixtures thereof.
[0044] Synthetic lubricating oils are useful and include hydrocarbon oils
such as polymerised and interpolymerised olefins (e.g., polybutylenes,
polypropylenes, propyleneisobutylene copolymers); poly(1-hexenes), poly(1-
octenes), poly(1-decenes), and mixtures thereof; alkyl-benzenes (e.g.
dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-
benzenes); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);
alkylated diphenyl ethers and alkylated diphenyl sulphides and the
derivatives,
analogs and homo logs thereof or mixtures thereof.
[0045] Other synthetic lubricating oils include polyol esters (such as
Priolube03970), diesters, liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, and the diethyl ester of decane
phosphonic acid), or polymeric tetrahydrofurans. Synthetic oils include those
produced by Fischer-Tropsch reactions and typically may be hydroisomerised
Fischer-Tropsch hydrocarbons or waxes. In one embodiment oils include those
prepared by a Fischer-Tropsch gas-to-liquid synthetic procedure as well as
other gas-to-liquid oils.
[0046] Oils of lubricating viscosity may also be defined as specified in
the
American Petroleum Institute (API) Base Oil Interchangeability Guidelines.
The five base oil groups are as follows: Group I (sulphur content >0.03 wt %,
and/or <90 wt % saturates, viscosity index 80-120); Group II (sulphur content
<0.03 wt %, and >90 wt % saturates, viscosity index 80-120); Group III
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(sulphur content <0.03 wt %, and >90 wt % saturates, viscosity index >120);
Group IV (all polyalphaolefins (PA0s)); and Group V (all others not included
in Groups I, II, III, or IV). The oil of lubricating viscosity comprises an
API
Group I, Group II, Group III, Group IV, Group V oil or mixtures thereof.
Often the oil of lubricating viscosity is an API Group I, Group II, Group III,
Group IV oil or mixtures thereof. Alternatively the oil of lubricating
viscosity
is often an API Group II, Group III or Group IV oil or mixtures thereof
[0047] The amount of the oil of lubricating viscosity present is
typically the
balance remaining after subtracting from 100 wt % the sum of the amount of
the polymer, the antiwear agent, the corrosion inhibitor and other performance
additives.
[0048] The lubricating composition may be in the form of a concentrate
and/or a fully formulated lubricant. If the dispersant, the antioxidant and
the
corrosion inhibitor are in the form of a concentrate (which may be combined
with additional oil to form, in whole or in part, a finished lubricant), the
ratio of
the components (a), (b) and (c) (i.e. the dispersant, the antioxidant and the
corrosion inhibitor to the oil of lubricating viscosity and/or to diluent oil
include
the ranges of about 1:99 to about 99:1 by weight, or about 80:20 to about
10:90
by weight.
Other Performance Additives
[0049] The composition of the invention optionally further includes at
least
one other performance additive. The other performance additives include
antiwear agents, viscosity index improvers (that is viscosity modifiers), foam
inhibitors, demulsifiers, pour point depressants, foam inhibitors, a
carboxylic
acid or anhydride, and mixtures thereof.
[0050] The total combined amount of the other performance additive
compounds present on an oil free basis may include ranges of 0 wt % to about
wt %, or about 0 wt % to about 5 wt %, or about 0.005 wt % to about 4 wt %,
or about 0.05 wt % to about 2.5 wt %, or about 0.1 wt % to about 1.5 wt % of
the
composition. Although one or more of the other performance additives may be
present, it is common for the other performance additives to be present in
different amounts relative to each other.
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Antiwear Agent
[0051] In one embodiment the antiwear agent comprises a phosphorus-
containing acid, salt or ester, or mixtures thereof. In one embodiment the
antiwear agent is in the form of a mixture.
[0052] The antiwear agent includes those derived from phosphoric acid,
phosphorous acid, thiophosphoric acid, thiophosphorous acid, or mixtures
thereof
[0053] In one embodiment the antiwear agent includes (i) a non-ionic
phosphorus compound; (ii) an amine salt of a phosphorus compound; or (iii) an
ammonium salt of a phosphorus compound.
[0054] In one embodiment the antiwear agent comprises an ammonium or
amine salt of a phosphorus-containing acid or ester.
[0055] The amine salt of a phosphorus acid or ester includes phosphoric
acid esters and amine salts thereof; dialkyldithiophosphoric acid esters and
amine salts thereof; amine salts of phosphites; and amine salts of phosphorus-
containing carboxylic esters, ethers, and amides; and mixtures thereof.
[0056] The amine salt of a phosphorus acid or ester may be used alone or
in
combination.
[0057] In one embodiment the amine salt of a phosphorus acid or ester
includes a partial amine salt, or a partial amine-metal salt compound or
mixtures thereof. In one embodiment the amine salt of a phosphorus acid or
ester further contains a sulphur atom in the molecule.
[0058] The amine salt may be prepared from amines that include primary
amines, secondary amines, tertiary amines, and mixtures thereof. The amines
include those with at least one hydrocarbyl group, or, in certain embodiments,
two or three hydrocarbyl groups. In different embodiments the hydrocarbyl
groups contain about 2 to about 30, or about 8 to about 26, or about 10 to
about
20, or about 13 to about 19 carbon atoms.
[0059] Primary amines include ethylamine, propylamine, butylamine,
2-ethylhexylamine, octylamine, and dodecylamine, as well as such fatty amines
as n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine,
n-hexadecylamine, n-octadecylamine and oleyamine. Other useful fatty amines
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include commercially available fatty amines such as "Armeen " amines
(products available from Akzo Chemicals, Chicago, Illinois), such as Armeen
C, Armeen 0, Armeen OL, Armeen T, Armeen HT, Armeen S and Armeen SD,
wherein the letter designation relates to the fatty group, such as coco,
oleyl,
tallow, or stearyl groups.
[0060] Examples of suitable secondary amines include dimethylamine,
diethylamine, dipropylamine, dibutylamine, diamylamine, dihexylamine,
diheptylamine, methylethylamine, ethylbutylamine and ethylamylamine. The
secondary amines also include cyclic amines such as piperidine, piperazine and
morp ho line .
[0061] The amine may also be a tertiary-aliphatic primary amine. The
aliphatic group on the tertiary-aliphatic primary amine in different
embodiments contains about 4 to about 30, or about 6 to about 26, or about 8
to
about 24 carbon atoms. Tertiary alkyl amines include monoamines such as tert-
butylamine, tert-hexylamine, 1-methyl-1-amino-cyclohexane, tert-octylamine,
tert-decylamine, tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanylamine, and tert-octacosanylamine.
[0062] In one embodiment the amine salt of a phosphorus acid or ester
includes an amine with about C11 to about C14 tertiary alkyl primary groups or
mixtures thereof. In one embodiment the amine salt of a phosphorus compound
includes an amine with about C14 to about C18 tertiary alkyl primary amines or
mixtures thereof. In one embodiment the amine salt of a phosphorus compound
includes an amine with about C18 to about C22 tertiary alkyl primary amines or
mixtures thereof.
[0063] Mixtures of amines may also be used in the invention. In one
embodiment a useful mixture of amines is "Primene0 81R" and "Primene0
JMT." Primene0 81R and Primene0 JMT (both produced and sold by Rohm &
Haas) are mixtures of C11 to C14 tertiary alkyl primary amines and C18 to C22
tertiary alkyl primary amines respectively.
[0064] In one embodiment the amine salt of a phosphorus acid or ester is
the
reaction product of a C14 to C18 alkylated phosphoric acid with Primene0 81R
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(produced and sold by Rohm & Haas) which is a mixture of Ci 1 to C14 tertiary
alkyl primary amines.
[0065] Examples of the amine salt of a phosphorus acid or ester include
the
reaction product(s) of isopropyl, methyl-amyl (1,3-dimethylbutyl or mixtures
thereof), 2-ethylhexyl, heptyl, octyl, nonyl, decyl, dodecyl, butadecyl,
hexadecyl, octadecyl or eicosyl phosphoric (or dithiophosphoric) acids with
ethylene diamine, morpholine, 2-ethylhexyl amine or Primene0 81R, and
mixtures thereof. In one embodiment the antiwear agent comprises an amine
salt of a phosphorus acid or ester or mixtures thereof In one embodiment the
phosphorus acid or ester is a C14-C18-alkyl phosphorus acid or ester with
Primene0 81R or 2-ethylhexyl amine.
[0066] In one embodiment the dithiophosphoric acids include those reacted
with an epoxide or a glycol. This reaction product is further reacted with a
phosphorus acid, anhydride, or lower ester. The epoxide includes an aliphatic
epoxide or a styrene oxide. Examples of useful epoxides include ethylene
oxide, propylene oxide, butene oxide, octene oxide, dodecene oxide, styrene
oxide and the like. In one embodiment the epoxide is propylene oxide. The
glycols include aliphatic glycols, wherein the aliphatic groups of the glycols
in
different embodiments have about 2 to about 12, or about 2 to about 6, or
about 2
to about 3 carbon atoms. The dithiophosphoric acids, glycols, epoxides,
inorganic phosphorus reagents and methods of reacting the same, are described
in U.S. Patent numbers 3,197,405 and 3,544,465. The resulting acids may then
be salted with amines. An example of a suitable dithiophosphoric acid is
prepared
by adding phosphorus pentoxide (about 64 grams) at about 58 C over a period
of about 45 minutes to about 514 grams of hydroxypropyl 0,0'-di(1,3-
dimethylbutyl)phosphorodithioate (prepared by reacting di(1,3-dimethylbuty1)-
phosphorodithioic acid with about 1.3 moles of propylene oxide at about 25
C).
The mixture is heated at about 75 C for about 2.5 hours, mixed with
diatomaceous earth and filtered at about 70 C. The filtrate contains about
11.8% by weight phosphorus, about 15.2% by weight sulphur, and has an acid
number of about 87 (bromophenol blue).
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[0067] In one
embodiment the antiwear agent comprises an amide-
containing dithiophosphorus acid ester. A more detailed description for the
amide-containing dithiophosphorus acid ester is found in US 4,938,884. A
description of the molecular structure is found in column 2, lines 4 to 28.
Suitable examples prepared are disclosed in Examples 1 to 7 (column 8, line 45
to column 10, line 13 of US 4,938,884). Typically the amide-containing
dithiophosphorus acid ester is prepared by the addition of dithiophosphoric
acid
to an acrylamide, such as acrylamide,
methacrylamide,
methylenebisacrylamide, or methylenebismethacrylamide. In one embodiment
the amide-containing dithiophosphorus acid ester includes a
methylenebisacrylamide, or methylenebismethacrylamide product prepared
from prepared by the addition of a dithiophosphoric acid to acrylamide to form
an
adduct; and subsequent reaction of the adduct with formaldehyde to make the
methylene coupled product.
[0068] In one
embodiment the antiwear agent comprises a carboxylic acid-
containing dithiophosphorus acid ester, for example 3-(bis-pentoxy-
thiophosphorylsulphany1)-propionic acid methyl ester,
3 -(dibutoxy-
thiophosphorylsulphany1)-propionic acid methyl ester, or mixtures thereof.
[0069] In one
embodiment the antiwear agent comprises a non-ionic
phosphorus compound. Typically the phosphorus atom in the non-ionic
phosphorus compound may have an oxidation state of +3 or +5. The different
embodiments comprise phosphite ester, phosphate esters, or mixtures thereof.
[0070] In one
embodiment the antiwear agent includes a non-ionic
phosphorus compound that is a hydrocarbyl phosphite. The hydrocarbyl-
substituted phosphite of the invention includes those represented by the
formula:
R -0 H
\ /
R--0 \
0
wherein each R" independently is hydrogen or a hydrocarbyl group, with the
proviso that at least one of the R" groups is hydrocarbyl.
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[0071] Each
hydrocarbyl group of R' in different embodiments contains at
least about 2, or at least about 4 carbon atoms. Typically, the combined total
sum of carbon atoms present on both R" groups is less than about 45, or is
less
than about 35, or is less than about 25. Examples of suitable ranges for the
number of carbon atoms present on R groups include about 2 to about 40,
about 3 to about 24, or about 4 to about 20. Examples of suitable hydrocarbyl
groups include propyl, butyl, t-butyl, pentyl, hexyl, dodecyl, butadecyl,
hexadecyl, or octadecyl groups. Generally the hydrocarbyl phosphite is soluble
or at least dispersible in oil. In one embodiment the hydrocarbyl phosphite is
di-butyl hydrogen phosphite or a C16-18 alkyl or di-alkyl hydrogen phosphite.
A
more detailed description of the non-ionic phosphorus compound is included in
column 9, line 48 to column 11, line 8 of US 6,103,673.
[0072] In one
embodiment the antiwear agent includes a phosphate ester.
Examples of a suitable phosphate ester include triaryl phosphates such as
tricresyl phosphate, triphenyl phosphate, tri-dimethylphenyl phosphate, tri-
butylphenyl phosphate, or mixtures thereof.
[0073] In one
embodiment the antiwear agent includes a thiophosphate
ester. Examples of a suitable thiophosphate ester include triaryl
thiophosphates
such as tricresyl thiophosphate, triphenyl thiophosphate, tri-dimethylphenyl
thiophosphate, tri-butylphenyl thiophosphate, or mixtures thereof.
[0074] In
different embodiments the antiwear agent is present in ranges
including about 0 wt % to about 5 wt %, or about 0.001 wt % to about 2 wt %,
or about 0.05 wt % to about 1.5 wt %, or about 0.1 wt % to about 1 wt % of the
lubricating composition.
Viscosity Modifiers
[0075]
Viscosity modifiers include hydrogenated copolymers of styrene-
butadiene, ethylene-propylene copolymers, polyisobutenes, hydrogenated
styrene-isoprene copolymers, hydrogenated isoprene
polymers,
polymethacrylate, polyacrylate, polyalkyl styrenes, hydrogenated alkenyl aryl
conjugated diene copolymers, polyolefins, and esters of maleic anhydride-
styrene copolymers.
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[0076] Other performance additives such as foam inhibitors including
copolymers of ethyl acrylate and 2-ethylhexylacrylate and optionally vinyl
acetate; demulsifiers including trialkyl phosphates, polyethylene glycols,
polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene
oxide) polymers; pour point depressants including esters of maleic anhydride-
styrene copolymers, polymethacrylates, polyacrylates or polyacrylamides; and
seal swell agents including Exxon Necton37TM (FN 1380) and Exxon Mineral
Seal Oil (FN 3200); and dispersant viscosity modifiers (often referred to as
DVM) include functionalised polyolefins, for example, ethylene-propylene
copolymers that have been functionalized with the reaction product of maleic
anhydride and an amine, a polymethacrylate functionalised with an amine, or
styrene-maleic anhydride copolymers reacted with an amine; may also be used
in the composition of the invention.
Industrial Application
[0077] The method of the invention is useful for lubricating a mechanical
device typically requiring a working fluid, a hydraulic fluid, a circulating
oil or
a turbine oil.
[0078] In one embodiment the mechanical device requires a fluid selected
from the group consisting of a working fluid, a hydraulic fluid, a circulating
oil, a turbine oil and mixtures thereof
[0079] In different embodiments the mechanical device is a hydraulic
system, a turbine system, or a circulating oil system.
[0080] The following examples provide illustrations of the invention.
These
examples are non exhaustive and are not intended to limit the scope of the
invention.
EXAMPLES
Lubricating Compositions EX1 to EX5
[0081] A series of lubricating compositions are prepared containing the
following additives: a borated dispersant, an amine salt of a phosphorus
compound, a mixture of phenolic and aminic antioxidants, two or more
corrosion inhibitors, and antifoam agents. The combined total treat-rate of
all
the additives (on an oil-free basis, i.e. excluding normal amount of diluent
oil
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commonly associated with each additive) is about 1.47 wt % for Example 1
(EX1), about 1.48 wt% for Example 2 (EX2), about 1.76 wt % for Example 3
(EX3), about 1.40 wt % for Example 4 (EX4) and about 1.27 wt % for Example
(EX5).
[0082] Examples EX1 to EX5 are evaluated in the following tests: (i)
oxidation stability of steam turbine oils using ASTM Method D2272, (ii)
kinematic viscosity at about 40 C using ASTM method D445, and (iii) thermal
stability of hydraulic fluids after heat stressing of the fluid utilising the
"Cincinnati Machine Thermal Stability Test" Procedure A. The Cincinnati
Machine Thermal Stability Test evaluates steel and copper corrosion and
thermal stability.
[0083] The data obtained for tests (i) and (ii) are shown in Table 1. The
data obtained for test (iii) are shown in Table 2.
Table 1
Test (ASTM Method) EX1 EX2 EX3 EX4 EX5
D2272 (minutes) 211 222 248 215 268
D445 (mm2/s) 32.74 32.75 32.95 32.85 32.84
Table 2
Cincinnati Machine Thermal EX1 EX2 EX3 EX4 EX5
Stability Test
Copper Rating 3 3 3 4 5
Copper weight loss (mg) 0.7 1.2 0.2 -2.7 0
Steel Rating 1 1 1 1 1
Steel weight loss (mg) 0.2 0.4 0.1 0 0.3
Sludge Formed (mg/100 ml of oil) 0.95 11 0.65 0.6 3.6
[0084] The data obtained indicate that the lubricating compositions of
the
invention are capable of providing a hydraulic fluid, turbine oil or
circulating
oil with at least one of acceptable sludge performance, acceptable thermal
stability and acceptable oxidation stability.
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100851 While the
invention has been explained in relation to its various
embodiments, it is to be understood that various modifications thereof will
become apparent to those skilled in the art upon reading the specification.
The
scope of the claims should not be limited by the embodiments set forth herein,
but should be given the broadest interpretation consistent with the
description
as a whole.
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