Note: Descriptions are shown in the official language in which they were submitted.
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HYDROCARBON-BASED LUBRICANTS WITH POLYETHER
FIELD OF THE INVENTION
[0001] The present invention relates to hydrocarbon-based
lubricants and methods.
INTRODUCTION TO THE DISCLOSURE
[0002] This section provides information helpful in understanding
the invention but
that is not necessarily prior art.
[0003] Hydrocarbon lubricants such as hydrocarbon oils are
susceptible to
oxidation and varnish formation during high temperature uses. The petroleum
industry over
the years has eliminated some of the impurities from crude oil via
hydrocracking or produced
synthetic hydrocarbons to minimize oxidation problems later on. In another
measure taken to
address the problem, nitrogen has been used to blanket the reservoir to
prevent a hydrocarbon
oil from coming in contact with oxygen. More recently, companies have
developed varnish
prediction test methods and varnish removal filters to filter out the soluble
varnish. In spite
of such efforts it still becomes necessary after a period of time in use to
remove used oil that
has filled with sludge and varnish and recharge the system with new oil.
Further, varnish
deposits onto machine parts can cause the parts to stick and interfere with
operation of a
machine.
[0004] Both draining and refilling a lubrication system and use of a
varnish
removal filtration system are expensive options and cannot guarantee that
varnish is not
deposited onto working machine parts. While there has been progress slowing
the oxidation
process, predicting the varnish formation, and removing some of the varnish
via filtration,
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varnish can only be removed by filtration if the oil makes its way back to the
filter. Oil out in
the lines of a lubrication system can continue to degrade and deposit varnish,
causing
problems with operation of machinery. Dispersants may help keep soft varnish
particles
suspended in a hydrocarbon lubricant, but the dispersant micelles formed
increase lubricant
viscosity and affect performance of the lubricant.
SUMMARY OF THE DISCLOSURE
[0005] This section provides a general summary rather than a
comprehensive
disclosure of the full scope of the invention and all its features.
[0006] Disclosed are methods in which an aliphatic polyether selected from:
(a)
polyallcylene oxides with monomer units having 3 to 6 carbon atoms, preferably
3 to 5 carbon
atoms, more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms
and
(b) polyvinyl ethers with ether groups having 2 to 8 carbon atoms, preferably
2 to 7 carbon
atoms, more preferably 2 to 6 carbon atoms, still more preferably 2 to 5
carbon atoms, and most
preferably 2 to 4 carbon atoms is added to a hydrocarbon lubricants,
particularly hydrocarbon
oils; such methods in which the hydrocarbon lubricant, particularly a
hydrocarbon oil, comprises
oxidation products that are dissolved by the addition of the aliphatic
polyether; hydrocarbon
lubricant, particularly hydrocarbon oil, containing an aliphatic polyether
selected from: (a)
polyallcylene oxides with monomer units having 3 to 6 carbon atoms, preferably
3 to 5 carbon
atoms, more preferably 3 or 4 carbon atoms, and most preferably 3 carbon atoms
and (b)
polyvinyl ethers with ether groups having 2 to 8 carbon atoms, preferably 2 to
7 carbon atoms,
more preferably 2 to 6 carbon atoms, still more preferably 2 to 5 carbon
atoms, and most
preferably 2 to 4 carbon atoms; lubrication systems including these
hydrocarbon lubricants or
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hydrocarbon oils; machines including these lubrication systems; and methods of
operating
machines including these lubrication systems.
[0007] In various embodiments of these, the aliphatic polyether is
selected from (a)
aliphatic polyethers having a formula
R-0¨(¨R10¨)¨R2
n (I)
wherein R and R2 are independently selected from aliphatic hydrocarbyl groups
having one to
about four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group; RI is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms,
preferably 3 to 5 carbon atoms, more preferably 3 or 4 carbon atoms, and most
preferably 3
carbon atoms; and n is an integer from 4 to about 50 and (b) aliphatic
polyvinyl ether
homopolymers and copolymers with monomer units having a formula
C¨C
I
OR3 (II)
or a formula
¨ C¨ C ¨
I
0R40R5 (III)
wherein each R3 is independently selected from aliphatic hydrocarbyl groups
having from 2 to 8
carbon atoms, preferably 2 to 7 carbon atoms, more preferably 2 to 6 carbon
atoms, still more
preferably 2 to 5 carbon atoms, and most preferably 2 or 3 or 4 carbon atoms
and each R4 and R5
is independently selected from hydrocarbyl groups having from 1 to about 3
carbon atoms,
preferably 1 or 2 carbon atoms, with the caveat that the number of carbon
atoms in R4 and R5
together is from about 2 to about 6, preferably 2 or 3 or 4. The polyether has
a number average
molecular weight of from about 300 to about 3000 as determined by gel
permeation
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chromatography using polystyrene standards. The polyether may be added to the
hydrocarbon
lubricant or hydrocarbon oil or included in a hydrocarbon lubricant or
hydrocarbon oil in an
amount from about 2 wt% to about 20 wt% of the polyether, preferably from
about 5 wt% to
about 20 wt% of the polyether, based on total lubricant weight or in an amount
so that the
lubricant or oil contains from about 2% to about 7% by weight ether linkages,
preferably from
about 4 to about 6% by weight ether linkages, based on total lubricant weight.
[0008] In various embodiments, a hydrocarbon lubricant or oil
containing
oxidation products or varnish is treated by adding to the lubricant or oil an
aliphatic polyether
selected from (a) aliphatic polyethers having a formula
R-0¨(¨R10¨)¨R2
n (I)
wherein R and R2 are independently selected from aliphatic hydrocarbyl groups
having one to
about four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group; RI is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms,
preferably 3 to 5 carbon atoms, more preferably 3 or 4 carbon atoms, and most
preferably 3
carbon atoms; and n is an integer from 4 to about 50 and (b) aliphatic
polyvinyl ether
homopolymers and copolymers with monomer units having a formula
C¨C
I
OR3 (II)
or a formula
¨ C¨ C ¨
I
0R40R5 (III)
wherein each R3 is independently selected from aliphatic hydrocarbyl groups
having from 2 to 8
carbon atoms, preferably 2 to 7 carbon atoms, more preferably 2 to 6 carbon
atoms, still more
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preferably 2 to 5 carbon atoms, and most preferably 2 or 3 or 4 carbon atoms
and each R4 and R5
is independently selected from hydrocarbyl groups having from 1 to about 3
carbon atoms,
preferably 1 or 2 carbon atoms, with the caveat that the number of carbon
atoms in R4 and R5
together is from about 2 to about 6, preferably 2 or 3 or 4. The polyether has
a number average
molecular weight of from about 300 to about 3000 as determined by gel
permeation
chromatography using polystyrene standards. The hydrocarbon lubricant or
hydrocarbon oil
containing oxidation products or varnish may be treated with from about 2 wt%
to about 20 wt%
of the polyether, preferably from about 5 wt% to about 20 wt% of the
polyether, based on total
treated lubricant weight or may be added in an amount so that the treated
lubricant contains from
about 2% to about 7% by weight ether linkages, preferably from about 4 to
about 6% by weight
ether linkages, based on total treated lubricant or oil weight or may be added
in an amount so
that both of these conditions (2-20 or 5-20 wt% of the polyether and 2-7 or 4-
6 wt% of the ether
linkages) exist.
[0009] In various embodiments, the polyether-containing
hydrocarbon
lubricants, particularly hydrocarbon oils, are used in lubrication systems in
which the lubricant
or oil reaches temperatures above about 100 C. or in which the hydrocarbon
lubricant or oil is
subject to oxidative conditions.
[0010] The lubricants, particularly the hydrocarbon oils, may be
used in
lubrication systems for turbines, hydraulics, hydrostatic drives, in mobile
equipment hydraulics,
and in other such machines where cleanliness of the oil lubricant is an issue.
[0011] The disclosed lubricant compositions and methods minimize
or prevent
varnish formation and extend oil life of hydrocarbon oils used in applications
in which they are
exposed to high temperatures or oxidative conditions during use. In one
method, the lubricant is
a hydrocarbon oil used to lubricate a power generation turbine. The lubricant
dissolves
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lubricant oxidation products (pre-varnish) and reduces pentane insolubles.
This prevents
build up of varnish on lubricated surfaces such as turbine system surfaces,
which can cause
sticky valves and turbine trips of the power generator.
[0012] While not wishing to be bound by theory, it is believed
that the
polyalkylene oxide homopolymers or polyvinyl ethers do not behave as
dispersants for the
oxidation products and varnish particles but instead increase the polarity of
the base
hydrocarbon oil to allow the hydrocarbon oil to dissolve the oxidation
products and varnish
particles. The dissolved oxidation products do not agglomerate.
[0013] The disclosed lubricant compositions and methods
revitalize used oils
(reduced VPR rating) so they do not have to drained and refilled, which saves
on waste
disposal, eliminates the need to purchase expensive varnish removal filtration
systems, and
prevents or diminishes future varnish formation to extend oil life.
[0014] "A," "an," "the," "at least one," and "one or more" are used
interchangeably to indicate that at least one of the item is present; a
plurality of such items may
be present unless the context clearly indicates otherwise. All numerical
values of parameters
(e.g., of quantities or conditions) in this specification, including the
appended claims, are to be
understood as being modified in all instances by the term "about" whether or
not "about"
actually appears before the numerical value. "About" indicates that the stated
numerical value
allows some slight imprecision (with some approach to exactness in the value;
approximately or
reasonably close to the value; nearly). If the imprecision provided by "about"
is not otherwise
understood in the art with this ordinary meaning, then "about" as used herein
indicates at least
variations that may arise from ordinary methods of measuring and using such
parameters. In
addition, disclosure of ranges includes disclosure of all values and further
divided ranges within
the entire range.
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[0014a] A further embodiment is a lubricant composition comprising a
hydrocarbon oil and an aliphatic polyether selected from polyalkylene oxide
homopolymers
wherein the polyether has a number average molecular weight of from about 300
to about 3000
and has a formula
R R10-)¨ R2
wherein R and R2 are independently selected from hydrocarbyl groups having
one to four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group, RI is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms, and
n is an integer from 4 to 50; and wherein the lubricant composition comprises
at least one of: (a)
from about 2 wt% to about 20 wt% of the polyether and (b) from about 2% to
about 7% by
weight ether linkages from the polyether.
[0014b] A further embodiment is a method of treating a hydrocarbon lubricant
comprising an oxidation product, comprising adding to the lubricant an
aliphatic polyether
selected from polyalkylene oxide homopolymers having a formula
R ¨0¨e R'0-)¨ R2
wherein R and R2 are independently selected from hydrocarbyl groups having
one to four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group, RI is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms, and
n is an integer from 4 to 50, wherein the polyether has a number average
molecular weight of
from about 300 to about 3000 and wherein the polyether is added in an amount
such that the
lubricant comprises at least one of: (a) from about 2 wt% to about 20 wt% of
the polyether and
(b) from about 2% to about 7% by weight ether linkages from the polyether.
[0014c] A further embodiment is a method of reducing varnish formation in a
system lubricated with a hydrocarbon lubricant, comprising including in the
hydrocarbon
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lubricant an aliphatic polyether selected from polyalkylene oxide homopolymers
having a
formula
R ¨0--e WO-)¨R2
it
wherein R and R2 are independently selected from hydrocarbyl groups having
one to four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group, RI is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms, and
n is an integer from 4 to 50, wherein the polyether has a number average
molecular weight of
from about 300 to about 3000, wherein the polyether is free of surfactant
character in the
lubricant.
[0015] Further areas of applicability will become apparent from the
description
provided herein. It should be understood that the description and specific
examples are intended
for purposes of illustration only and are not intended to limit the scope of
the present disclosure.
DETAILED DESCRIPTION
[0016] A detailed description of exemplary, nonlimiting embodiments follows.
[0017] A hydrocarbon lubricant base stock is used in these methods and
compositions. Hydrocarbon base stocks may be manufactured using a variety of
different
processes including, but not limited to, distillation, solvent refining,
hydrogen processing,
oligomerization, esterification, and re-refining. Nonlimiting examples of
hydrocarbon base
stocks are aliphatic hydrocarbon oils, hydrocracked and severely hydrotreated
hydrocarbon oils,
furfural-refined paraffinic oil, solvent-refined naphthenic oil, and solvent-
refined aromatic oil;
synthetic hydrocarbon oils, such as poly(alpha-olefin) oils like hydrogenated
or partially
hydrogenated olefins including hydrogenated hexene oligomers, hydrogenated
octene oligomers,
hydrogenated decene oligomers, hydrogenated C6-10 oligomers, and hydrogenated
C8-10
oligomers; mineral oils such as liquid petroleum oils and solvent-treated or
acid-treated mineral
lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic
types such as
paraffinic neutral 100", and oils derived from coal or shale; alkylbenzenes
such as
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dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-
benzenes; polyphenyls
like biphenyls, terphenyls, alkylated polyphenyls; alkylated diphenyl ethers,
and mixtures of
these.
100181 The polyether-containing hydrocarbon lubricant may be made using a
hydrocarbon oil base stock or a fully formulated hydrocarbon lubricant,
particularly a fully
formulated hydrocarbon oil. The polyether-containing hydrocarbon lubricant or
oil may be
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formulated as a new, unused lubricant or oil or may be made from used
hydrocarbon
lubricant or oil containing oxidation products, such as varnish particles or
soft bodies, which
may further include one or more lubricant additives.
[0019] The hydrocarbon base oil or lubricant is combined with a
polyether
selected from polyalkylene oxide homopolymers and polyvinyl ether homopolymers
and
random copolymers. The polyalkylene oxide homopolymers have a formula
R-0¨(¨R10¨)¨R2
II (I)
wherein R and R2 are independently selected from aliphatic hydrocarbyl groups
having one to
about four carbon atoms and hydrogen, with the caveat that at least one of R
and R2 is a
hydrocarbyl group; R' is an aliphatic hydrocarbylene group having from 3 to 6
carbon atoms,
preferably 3 to 5 carbon atoms, more preferably 3 or 4 carbon atoms, and most
preferably 3
carbon atoms; and n is an integer from 4 to about 50, preferably from about 10
or from about 15
to about 25 or to about 30 or to about 35 or to about 40, especially
preferably from about 10 to
about 40 or from about 10 to about 35 or from about 15 to about 35. The
polyalkylene oxide
homopolymer has a number average molecular weight of at least 300. In
preferred
embodiments the polyalkylene oxide homopolymer has a number average molecular
weight of
up to about 3000, more preferably up to about 2000, and particular preferably
from about 500 to
about 1200. The number average molecular weight is determined by gel
permeation
chromatography using polystyrene standards.
[0020] Nonlimiting examples include polypropylene oxide and polybutylene
oxide
having optionally one hydroxyl endgroup and one alkoxide endgroup or, if there
is no
hydroxyl end group, two alkoxide endgroups, where the alkoxide endgroups may
be
methoxide, ethoxide, propoxide, isopropxide, n-butoxide, isobutoxide, sec-
butoxide and tert-
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butoxide endgroups. Such polyalkylene oxide polymers may be prepared using an
alcohol as
an initiator molecule by anionic polymerization of an alkylene oxide with base
catalysts, e.g.
alkali metal hydroxides like potassium hydroxide and sodium hydroxide, sodium
methoxide,
or metal sodium, or by cationic polymerization of an alkylene oxide with acid
catalysts such
as aluminum chloride, antimony pentachloride, boron trifluoride, iron(III)
chloride, or tin(IV)
chloride. Many alkoxide-terminated polyalkylene oxides are commercially
available, for
example from BASF under the tradename PLURASAFED and from Dow Chemical under
the tradename UCONTM.
[0021] The polyvinyl ether homopolymers and random copolymers have
monomer
units with a formula
C¨C
I
OR3 (II)
or a formula
¨ C¨C ¨
I
0R40R5 (III)
wherein each R3 is independently selected from aliphatic hydrocarbyl groups
having from 2 to 8
carbon atoms, preferably 2 to 7 carbon atoms, more preferably 2 to 6 carbon
atoms, still more
preferably 2 to 5, and most preferably 2 or 3 or 4 carbon atoms carbon atoms
and each R4 and R5
is independently selected from hydrocarbyl groups having from 1 to about 3
carbon atoms,
preferably 1 or 2 carbon atoms, with the caveat that the number of carbon
atoms in R4 and R5
together is from about 2 to about 6, preferably from about 2 or 3 or 4, more
preferably 2 or 3.
The polyvinyl ether has a number average molecular weight of from about 300 to
about 3000 as
determined by gel permeation chromatography using polystyrene standards.
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[0022] Various methods of polymerization of vinyl ethers are
discussed in WO
99/64484, In one example, vinyl
ether monomers may be polymerized at temperatures of -100 C to 25 C using a
cationic
initiator such as boron trifluoride, aluminum chloride, or tin(IV) chloride.
Nonlimiting
examples of suitable polyvinyl ethers include homopolymers and random
copolymers of
monovinyl ethers such as vinyl ethyl ether, vinyl propyl ether, vinyl
isopropyl ether, vinyl
butyl ether, vinyl isobutyl ether, vinyl tertbutyl ether, vinyl 2-methoxyethyl
ether, vinyl 2-
ethoxyethyl ether, vinyl 2-propoxyethyl ether, and vinyl isoamyl ether.
[0023] In various embodiments, the polyether-containing
hydrocarbon oil or other
lubricant that is prepared by combining the hydrocarbon oil or other
hydrocarbon lubricant and
polyether may contain from about 2 wt% to about 20 wt% of the polyether,
preferably from
about 5 wt% to about 20 wt% of the polyether, based on total polyether-
containing hydrocarbon
lubricant weight. In other embodiments, the hydrocarbon oil or hydrocarbon
lubricant contains
from about 2% to about 7% by weight ether linkages, preferably from about 4 to
about 6% by
weight ether linkages, based on total polyether-containing hydrocarbon
lubricant weight.
[0024] The polyether is not amphiphilic so as to form micelles as
would a
surfactant. Rather, it is understood that the polyether changes the
characteristics of the lubricant
to permit oxidation products and varnish particles to dissolve in the oil or
other hydrocarbon
lubricant.
[0025] The hydrocarbon oil or other hydrocarbon lubricant is preferably
free of
detergents, surfactants, and dispersants. The oil or lubricant may include one
or more additives
other than detergents, surfactants, and dispersants. Nonlimiting examples of
suitable additives
include antioxidants, anti-wear agents, extreme-pressure agents, friction-
reducing agents, metal
inactivating agents such as benzotriazoles, viscosity modifiers, pour point
depressants,
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stabilizers, corrosion inhibitors, and flammability suppressants. Such
additives may be used
alone or in any combination of two or more. There are no particular
restrictions on the inclusion
of such additives. Generally, additives such as these may be present at less
than or equal to
about 10% by weight of the lubricant composition. Various embodiments of the
lubricant
composition may include about 0.1 to about 5% by weight of an additive or a
combination of
additives or about 0.2 to about 2% by weight of an additive or a combination
of additives.
[0026] Nonlimiting examples of the antioxidants that can be used
include
phenolic antioxidants such as 2,6-di-t-butyl-4-methylphenol and 4,4'-
methylenebis(2,6-di-t-
butylphenol), and bisphenol A; amine and thiazine antioxidants such as p,p-
dioctylphenylamine, monooctyldiphenylamine, phenothiazine, 3,7-
dioctylphenothiazine,
N,N-di(2-naphthyl)-p-phenylenediamine, phenyl-l-naphthylamine, phenyl-2-
naphthylamine,
alkylphenyl- 1-naphthylamines, and alkylpheny1-2-naphthylamines; and sulfur-
containing
antioxidants such as alkyl disulfide, thiodipropionic acid esters and
benzothiazole. The
lubricant composition may comprise up to about 5.0 weight % antioxidants,
about 0.1 to
about 5 weight %, about 0.1 to about 2.0 weight %, or about 0.2 to about 0.8
weight %
antioxidants. The lubricant compositions may include one or a combination of
two or more
antioxidant compounds.
[0027] In certain embodiments, the hydrocarbon lubricant and
hydrocarbon
oil compositions may include one or more extreme pressure or anti-wear
additives.
Nonlimiting examples of suitable extreme pressure/antiwear additives include
sulfur- and
phosphorous-containing types such as phosphoric acid esters, acidic phosphoric
acid esters,
branched alkyl amine phosphates containing 5 to 20 carbon atoms,
thiophosphoric acid
esters, acidic phosphoric acid ester amine salts, and chlorinated phosphoric
acid esters and
phosphorous acid esters that are esters of phosphoric acid or phosphorous acid
with alkanols
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or polyether alcohols. Specific, nonlimiting examples of phosphoric acid
esters include
tributyl phosphate, tripentyl phosphate, trihexyl phosphate, triheptyl
phosphate, trioctyl
phosphate, trinonyl phosphate, tridecyl phosphate, triundecyl phosphate,
tridodecyl
phosphate, tritridecyl phosphate, tritetradecyl phosphate, tripentadecyl
phosphate,
trihexadecyl phosphate, triheptadecyl phosphate, trioctadecyl phosphate,
trioleyl phosphate,
triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyldiphenyl
phosphate, and
xylenyldiphenyl phosphate. Specific, nonlimiting examples of acidic phosphoric
acid esters
there may be mentioned monobutyl acid phosphate, monopentyl acid phosphate,
monohexyl
acid phosphate, monoheptyl acid phosphate, monooctyl acid phosphate, monononyl
acid
phosphate, monodecyl acid phosphate, monoundecyl acid phosphate, monododecyl
acid
phosphate, monotridecyl acid phosphate, monotetradecyl acid phosphate,
monopentadecyl
acid phosphate, monohexadecyl acid phosphate, monoheptadecyl acid phosphate,
monooctadecyl acid phosphate, monooleyl acid phosphate, dibutyl acid
phosphate, dipentyl
acid phosphate, dihexyl acid phosphate, diheptyl acid phosphate, dioctyl acid
phosphate,
dinonyl acid phosphate, didecyl acid phosphate, diundecyl acid phosphate,
didodecyl acid
phosphate, ditridecyl acid phosphate, ditetradecyl acid phosphate,
dipentadecyl acid
phosphate, dihexadecyl acid phosphate, diheptadecyl acid phosphate,
dioctadecyl acid
phosphate and dioleyl acid phosphate. Specific, nonlimiting examples of
thiophosphoric acid
esters include tributyl phosphorothionate, tripentyl phosphorothionate,
trihexyl
phosphorothionate, triheptyl phosphorothionate, trioctyl phosphorothionate,
trinonyl
phosphorothionate, tridecyl phosphorothionate, triundecyl phosphorothionate,
tridodecyl
phosphorothionate, tritridecyl phosphorothionate, tritetradecyl
phosphorothionate,
tripentadecyl phosphorothionate, trihexadecyl phosphorothionate, triheptadecyl
phosphorothionate, trioctadecyl phosphorothionate, trioleyl phosphorothionate,
triphenyl
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phosphorothionate, tricresyl phosphorothionate, trixylenyl phosphorothionate,
cresyldiphenyl
phosphorothionate, and xylenyldiphenyl phosphorothionate. Specific,
nonlimiting examples
of amine salts of acidic phosphoric acid esters include salts of acidic
phosphoric acid esters
with amines such as methylamine, ethylamine, propylamine, butylamine,
pentylamine,
hexylamine, heptylamine, octylamine, dimethylamine, diethylamine,
dipropylamine,
dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine,
trimethylamine,
triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine,
triheptylamine,
and trioctylamine. Specific, nonlimiting examples of chlorinated phosphoric
acid esters
include tris(dichloropropyl) phosphate, tris(chloroethyl) phosphate,
tris(chlorophenyl)
phosphate, and polyoxyalkylene bis[di(chloroalkyl)]phosphate. As phosphorous
acid esters
there may be mentioned dibutyl phosphite, dipentyl phosphite, dihexyl
phosphite, diheptyl
phosphite, dioctyl phosphite, dinonyl phosphite, didecyl phosphite, diundecyl
phosphite,
didodecyl phosphite, dioleyl phosphite, diphenyl phosphite, dicresyl
phosphite, tributyl
phosphite, tripentyl phosphite, trihexyl phosphite, triheptyl phosphite,
trioctyl phosphite,
trinonyl phosphite, tridecyl phosphite, triundecyl phosphite, tridodecyl
phosphite, trioleyl
phosphite, triphenyl phosphite, and tricresyl phosphite. The extreme
pressure/antiwear
additives may be used individually or in any combination, in any desired
amount. In various
embodiments, the lubricant or oil composition may include about 0.01 weight %
to about 5.0
weight %, about 0.01 weight % to about 4.0 weight %, about 0.02 weight % to
about 3.0
weight %, or 0.1 weight % to about 5.0 weight % each of extreme pressure
additives and
antiwear additives. These additives may be used alone or in any combination.
[0028] In various embodiments, the hydrocarbon lubricant or
hydrocarbon oil
may include one or more corrosion inhibitors, such as those selected from
isomeric mixtures
of N,N-bis(2-ethylhexyl)-4-methy1-1H-benzotriazole-1-methylamine and N,N-bis(2-
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ethylhexyl)-5-methy1-1H-benzotriazole-1-methylamine. The hydrocarbon lubricant
or
hydrocarbon oil may include about 0.01 to about 1.0 weight % of one or more
corrosion
inhibitors, about 0.01 to about 0.5 weight % of one or more corrosion
inhibitors, or about
0.05 to about 0.15 weight % of one or more corrosion inhibitors.
[0029] Viscosity modifiers (or viscosity index improvers) are polymeric
materials, typical examples of these being polyolefins, such as ethylene-
propylene copolymers,
hydrogenated styrene-isoprene block copolymers, hydrogenated copolymers of
styrene-
butadiene, copolymers of ethylene and propylene, acrylic polymers produced by
polymerization of acrylate and methacrylate esters, hydrogenated isoprene
polymers,
polyalkyl styrenes, hydrogenated alkenyl arene conjugated diene copolymers,
polyolefins,
esters of maleic anhydride-styrene copolymers, and polyisobutylene.
[0030] Nonlimiting examples of pour point depressants include
polyalkyl
methacrylates, polyalkyl acrylates, polyvinyl acetate, polyalkylstylenes,
polybutene,
condensates of chlorinated paraffin and naphthalene, and condensates of
chlorinated paraffin
and phenol
[0031] Nonlimiting examples of flammability suppresants include
trifluorochloromethane, trifluoroiodomthane, phosphate esters and other
phosphorous
compounds, and iodine- or bromine-containing hydrocarbons, hydrofloroarbons,
or
fluorocarbons.
[0032] A hydrocarbon lubricant or hydrocarbon oil may be treated by adding
to the lubricant or oil a polyether selected from polyalkylene oxide
homopolymers and
polyvinyl ethers as described. The hydrocarbon lubricant or hydrocarbon oil
that is treated
may contain an oxidation product, e.g. varnish or pre-varnish oxidation
products, and the
polyether may be added in an amount sufficient to cause the oxidation products
to dissolve in
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the lubricant. In various embodiments, the polyether is added in an amount
such that the
lubricant or oil comprises at least one of: (a) from about 2 wt% to about 20
wt% or from
about 5 wt% to about 20 wt% of the polyether or from about 2% to about 7% by
weight or
from about 4 to about 6% by weight ether linkages from the polyether. In
various
embodiments the viscosity of a hydrocarbon oil or other lubricant containing
varnish, pre-
varnish, or other oxidation products is reduced by the addition of the
polyether to a greater
degree that would be expected based on a weighted average of the viscosity of
the
hydrocarbon oil or lubricant and the viscosity of the polyether.
[0033] A hydrocarbon lubricant or hydrocarbon oil treatment
composition for
treating hydrocarbon lubricant or hydrocarbon oil containing varnish or other
oxidation products
includes the polyether as described and at least one additive other than
detergents, surfactants,
and dispersants. In various embodiments, the additive is selected from
antioxidants, anti-wear
agents, extreme-pressure agents, friction-reducing agents, metal inactivating
agents such as
benzotriazoles, viscosity modifiers, pour point depressants, stabilizers,
corrosion inhibitors,
flammability suppressants, and combinations of these. In particular
embodiments, the lubricant
or oil treatment composition comprises the polyether and an antioxidant. The
lubricant or oil
treatment composition reduces the viscosity of a hydrocarbon lubricant or
hydrocarbon oil
containing varnish, pre-varnish, or other oxidation products to a greater
degree that would be
expected based on a weighted average of the viscosity of the hydrocarbon
lubricant or
hydrocarbon oil and the viscosity of the polyether treatment composition.
[0034] The oxidation products dissolve and do not agglomerate in
the
hydrocarbon lubricant or hydrocarbon oil containing the polyether. This is
demonstrated in
the following examples in which testing for Varnish Potential shows condemned
'used' oil
returning to good working condition. Viscosity of used hydrocarbon oil
decreases, ISO
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cleanliness codes decrease, pentane insolubles decrease, lubrication
properties increase, and
VPR (varnish potential rating) is reduced to 'as new fluid' acceptable for
use.
Examples
[0035] Example 1. Remediation of Used Turbine Oil
TM
[0036] A sample of used Chevron GST-32 turbine oil was removed from a
system
that had been experiencing system trips and varnish problems. The parameters
of the used oil
were measured according to the following published test methods.
[0037] VP Pentane Insolubles ¨ASTM D 893
[0038] Ultra-Centrifuge Sediment Rating ¨Mobil Method 1169
[0039] Filter Patch Colorimetry ¨ASTM W K 27308
[0040] Ruler %¨ ASTM D 6971
[0041] Varnish Potential Rating¨ ASTM D 4378
[0042] Viscosity (SUS)¨ ASTM D 445
[0043] Total Acid Number¨ ASTM D 664
[0044] Water Content¨ ASTM E 203
[0045] Particle Count¨ISO 4406.
[0046] The measured values of the used Chevron GST-32 turbine oil
as removed
from the system are shown in Table 1. The parameters of a new, unused sample
of Chevron
GST-32 turbine oil were also measured and are shown in Table 1.
[0047] A portion of 90 parts by weight of the used Chevron GST-32 turbine
oil was
combined with 10 parts by weight of polypropylene oxide, terminated with one
butyl ether
group and one hydroxyl group, having a number average molecular weight of
1000, and
= containing 0.6 wt% of the butylated reaction product of p-cresol and
dicyclopentadiene (CAS #
TM
68610-51-5) and 0.01 wt% Cobratec'122 (available form PMC Specialties Group
Inc.,
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Cincinnati, OH) to make a remediated turbine oil. The parameters of this
remediated Chevron
GST-32 turbine oil were measured and are shown in Table 1.
[0048] Theoretical values of the parameters were determined for a
combination of
90 parts by weight of the used Chevron GST-32 turbine oil combined with 10
parts by weight of
the polypropylene oxide by taking a weighted average of the values of the
individual fluids. The
theoretical values represent oil property values that would be expected if the
polyether had no
effect on the varnish particles contained in the used Chevron GST-32 turbine
oil. These values
are also shown in Table 1. The difference between the theoretical parameter
values and the
values actually obtained by combining the used turbine oil with the
polypropylene oxide
demonstrate that the added polypropylene oxide eliminated the soft varnish
particles from the
used turbine oil. The used Chevron GST-32 turbine oil remediated with 10 wt%
polypropylene
oxide had a 75% elimination of pentane insolubles, an ultra-centrifuge
sediment rating
equivalent to the new oil, and a reduction in measured color bodies. Results
of the Ruler test
show a 10% boost over the expected value in the antioxidant content of the
original Chevron
GST-32 antioxidant, which differs from the antioxidant that was combined with
the
polypropylene added to remediate the used oil. A 10-unit SUS drop in viscosity
for the
remediated oil is also evidence that the soft varnish particles have been
dissolved into the oil.
The polypropylene oxide also releases other polar molecules, such as water, as
the varnish
breaks up.
New Chevron Used Chevron Actual 90 wt% Theoretical 90
GST-32 GST-32 Chevron GST- wt% used Chevron
turbine oil turbine oil 32 turbine oil to GST-32
turbine oil
10 wt% to 10 wt%
Polypropylene Polypropylene
oxide oxide
VP Pentane 74 92 21 83
Insolubles (mg/L)
Ultra-Centrifuge 1 3 1 2.7
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Sediment Rating
Filter Patch 1 32 12 28
Colorimetry
Ruler % 100 74 72 67
Varnish Potential Low Elevated Low Elevated
Rating
Viscosity (SUS) , 161 176 163 172
cSt
Total Acid 0.07 0.44 0.10 0.42
Number (mg
KOH/g)
Water (ppm) 137 137 384 183.4
Particle Count 17/14/11 20/16/12 19/17/13 20/16/12
[0049] Example 2. Remediatton of Used Turbine Oil
TM
[0050] A sample of used Mobil SHC-824 turbine oil was removed from a system
that had excessive varnish. The parameters of the used oil were measured and
are given in
Table 2. A portion of 90 parts by weight of the used Mobil SHC-824 turbine oil
was combined
with 10 parts by weight of polypropylene oxide, terminated with one butyl
ether group and one
hydroxyl group, having a number average molecular weight of 1000, and
containing 0.6 wt% of
the butylated reaction product of p-cresol and dicyclopentadiene (CAS # 68610-
51-5) and 0.01
wt% Cobratec 122 (available form PMC Specialties Group Inc., Cincinnati, OH)
to make a
remediated turbine oil. The parameters of this remediated Mobil SHC-824
turbine oil were
measured and are shown in Table 2. Finally, theoretical values of replenishing
the lubrication
system with new Mobil SHC-824 turbine oil are shown in Table 2.
Used Mobil Actual 90 wt% Replenishing
SHC-824 Mobil SHC-824 with new Mobil
turbine oil turbine oil to 10 SHC-824
wt% turbine oil
Polypropylene
oxide
Viscosity (SUS), 161 148 158
cSt
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Total Acid 0.98 0.29 0.91
Number (mg
KOH/g)
Water (ppm) 81 211 133
Particle Count 24/21/21 23/18/18 24/21/21
[0051] The addition of the polypropylene oxide reduced the viscosity of the
turbine
oil by 3 cSt (10 SUS) below a theoretical value. This demonstrates that the
addition of the
polypropylene oxide significantly reduced the effective molecular weight of
the lubricant by
reducing the agglomeration of polar bodies that had formed soft varnish
particles in the used oil.
A reduction in total acid number demonstrates a re-established balance between
aminic and
phenolic antioxidants active in the used turbine fluid. The reduction in
particle count for the
remediated used oil shows that the added polypropylene oxide removed varnish
particles from
the used turbine oil by dissolving them.
[0052] The foregoing description of the embodiments has been provided for
purposes of illustration and description. It is not intended to be exhaustive
or to limit the
invention. Individual elements or features of a particular embodiment are
generally not limited
to that particular embodiment, but, where applicable, are interchangeable and
can be used in a
selected embodiment, even if not specifically shown or described. The same may
also be varied
in many ways. Such variations are not to be regarded as a departure from the
invention, and all
such modifications are intended to be included within the scope of the
invention.
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