Note: Descriptions are shown in the official language in which they were submitted.
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FUNCTIONAL FLUIDS LUBRICATING OIL COMPOSITIONS
BACKGROUND OF THE DISCLOSURE
[0001] Modern lubricating oil formulations are designed to exacting
specifications
often set by original equipment manufacturers. To meet such specifications,
various additives
are used, together with base oils of lubricating viscosity. Depending on the
application, a
typical lubricating oil composition may contain dispersants, detergents, anti-
oxidants, wear
inhibitors, rust inhibitors, corrosion inhibitors, foam inhibitors, and
friction modifiers just to
name a few. Different applications will govern the type of additives that will
go into a
lubricating oil composition.
[0002] A functional fluid is a term which encompasses a variety of fluids
including
but not limited to tractor hydraulic fluids, power transmission fluids
including automatic
transmission fluids, continuously variable transmission fluids and manual
transmission fluids,
hydraulic fluids, gear oils, power steering fluids, fluids used in wind
turbines and fluids
related to power train components. It should be noted that within each of
these fluids such as,
for example, automatic transmission fluids, there are a variety of different
types of fluids due
to the various transmissions having different designs which have led to the
need for fluids of
markedly different functional characteristics.
[0003] With respect to tractor hydraulic fluids, these fluids are all-
purpose (or multi-
purpose) products used for all lubricant applications in a tractor except for
lubricating the
engine. Also included as a tractor hydraulic fluid for the purposes of this
invention are so-
called Super Tractor Oil Universal fluids or "STOU" fluids, which also
lubricate the engine.
These lubricating applications may include lubrication of gearboxes, power
take-off and
clutch(es), rear axles, reduction gears, wet brakes, and hydraulic
accessories. The
components included within a tractor fluid must be carefully chosen so that
the final resulting
fluid composition will provide all the necessary characteristics required in
the different
applications. Such characteristics may include the ability to provide proper
frictional
properties for preventing wet brake and/or clutch chatter of oil immersed
brakes and clutches
while simultaneously providing the ability to actuate wet brakes and clutches,
particularly
provide power take-off (PTO) clutch performance. A tractor fluid must provide
sufficient
antiwear and extreme pressure properties as well as water
tolerance/filterability capabilities.
The extreme pressure (EP) properties of tractor fluids, important in gearing
applications, may
be demonstrated by the ability of the fluid to pass a spiral bevel test as
well as a straight spur
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gear test. The tractor fluid may need to pass wet brake chatter tests while
providing adequate
wet brake capacity when used in oil immersed disk brakes which are comprised
of cellulose,
bronze, graphitic-compositions and asbestos, among other materials. The
tractor fluid may
need to demonstrate its ability to provide friction retention for power shift
transmission
clutches such as those clutches which include, cellulose and graphitic
clutches, among other
materials.
[0004] When the functional fluid is a tractor hydraulic fluid, the fluids
must have
enough friction for the system to operate effectively. The term "friction
durability" will be
used to describe the property of the fluid to retain its original frictional
properties. For
example, a fluid with good friction durability will exhibit small changes in
the frictional
properties during its useful life. It is important that the tractor hydraulic
fluid maintains its
frictional properties throughout its life to ensure optimal operation of
brakes and clutches.
[0005] The present disclosure generally relates to lubricating oil
compositions which
improve or maintain frictional durability while maintaining low torque
variation at low speed
when used as tractor hydraulic fluids.
SUMMARY OF THE DISCLOSURE
[0006] In accordance with one embodiment of the present disclosure, there
is
provided a tractor hydraulic fluid composition which comprises:
(a) a major amount of an oil of lubricating viscosity, and
(b) a detergent system comprising:
(1) a low overbased sulfonate detergent;
(ii) a high overbased sulfonate detergent; and
(iii) a high overbased phenate detergent having an alkyl group derived from
an isomerized normal alpha olefin having from about 10 to about 40
carbon atoms per molecule.
[0007] Also provided is a method of improving frictional durability while
maintaining
low torque variation at low speed of a tractor hydraulic system comprising
lubricating said
hydraulic system with a lubricating oil composition comprising:
(a) a major amount of an oil of lubricating viscosity, and
(b) a detergent system comprising:
(1) a low overbased sulfonate detergent;
(ii) a high overbased sulfonate detergent; and
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(iii) a high overbased phenate detergent having an alkyl group
derived from
an isomerized normal alpha olefin having from about 10 to about 40
carbon atoms per molecule.
DETAILED DESCRIPTION OF THE DISLCOSURE
[0008] While the invention is susceptible to various modifications and
alternative
forms, specific embodiments thereof are herein described in detail. It should
be understood,
however, that the description herein of specific embodiments is not intended
to limit the
invention to the particular forms disclosed, but on the contrary, the
intention is to cover all
modifications, equivalents, and alternatives falling within the spirit and
scope of the invention
as defined by the appended claims.
[0009] To facilitate the understanding of the subject matter disclosed
herein, a number
of terms, abbreviations or other shorthand as used herein are defined below.
Any term,
abbreviation or shorthand not defined is understood to have the ordinary
meaning used by a
skilled artisan contemporaneous with the submission of this application.
DEFINITIONS
[0010] As used herein, the following terms have the following meanings,
unless
expressly stated to the contrary. In this specification, the following words
and expressions, if
and when used, have the meanings given below.
[0011] A "major amount" means in excess of 50 weight % of a composition.
[0012] A "minor amount" means less than 50 weight % of a composition,
expressed in
respect of the stated additive and in respect of the total mass of all the
additives present in the
composition, reckoned as active ingredient of the additive or additives.
[0013] "Active ingredients" or "actives" or "oil free" refers to additive
material that is
not diluent or solvent.
[0014] The abbreviation "ppm" means parts per million by weight, based on
the total
weight of the lubricating oil composition.
[0015] Total base number (TBN) was determined in accordance with ASTM
D2896. TBN numbers are reported on an "actives" or "oil-free" basis.
[0016] Metal ¨ The term "metal" refers to alkali metals, alkaline earth
metals, or
mixtures thereof
[0017] Kinematic viscosity at 100 C (KVioo) was determined in accordance
with
ASTM D445.
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[0018] Olefins ¨ The term "olefins" refers to a class of unsaturated
aliphatic
hydrocarbons having one or more carbon-carbon double bonds, obtained by a
number of
processes. Those containing one double bond are called mono-alkenes, and those
with two
double bonds are called dienes, alkyldienes, or diolefins. Alpha olefins are
particularly reactive
because the double bond is between the first and second carbons. Examples are
1-octene and
1-octadecene, which are used as the starting point for medium-biodegradable
surfactants.
Linear and branched olefins are also included in the definition of olefins.
[0019] Normal Alpha Olefins ¨ The term "Normal Alpha Olefins" refers to
olefins
which are straight chain, non-branched hydrocarbons with carbon-carbon double
bond present
in beginning and end of the chain.
[0020] Isornerzed Normal Alpha Olefin. The term Isomerized Normal Alpha
Olefin"
as used herein refers to an alpha olefin that has been subjected to
isomerization conditions
which results in an alteration of the distribution of the olefin species
present and/or the
introduction of branching along the alkyl chain. The isotnerized olefin
product may be obtained
by isomerizing a linear tA.1plia olefin containing from about 10 to about 40
carbon atoms,
preferably from about 20 to about 28 carbon atoms, and preferably from about
20 to about 24
carbon atoms.
[0021] All ASTM standards referred to herein are the most current versions
as of the
filing date of the present application.
[0022] In one aspect, the lubricating oil composition of the present
disclosure improves
frictional durability while maintaining low torque variation at low speed when
used as a tractor
hydraulic fluid. In another aspect, the lubricating oil composition of the
present disclosure
maintains frictional durability while maintaining low torque variation at low
speed when used
as a tractor hydraulic fluid
[0023] In one aspect, the lubricating oil composition of the present
disclosure
comprises a detergent system comprising: a low overbased sulfonate detergent,
a high
overbased sulfonate detergent; and a high overbased phenate detergent.
[0024] In another aspect, the detergent system of the present disclosure
provides
synergistic performance benefits when used in lubricating oil compositions for
tractor
hydraulic fluids.
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Oil of lubricatin2 viscosity
[0025] The oil of lubricating viscosity (sometimes referred to as "base
stock" or "base
oil") is the primary liquid constituent of a lubricant, into which additives
and possibly other
oils are blended, for example to produce a final lubricant (or lubricant
composition). A base oil
is useful for making concentrates as well as for making lubricating oil
compositions therefrom,
and may be selected from natural and synthetic lubricating oils and
combinations thereof
[0026] Natural oils include animal and vegetable oils, liquid petroleum
oils and
hydrorefined, solvent-treated mineral lubricating oils of the paraffinic,
naphthenic and mixed
paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal
or shale are also
useful base oils.
[0027] Synthetic lubricating oils include hydrocarbon oils such as
polymerized and
interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-
isobutylene
copolymers, chlorinated polybutylenes, poly( 1 -hexene s), poly( 1 -octene s),
poly( 1 -decene s) ;
alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes,
di(2-
ethylhexyl)benzenes; polyphenols (e.g., biphenyls, terphenyls, alkylated
polyphenols); and
alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives,
analogues and
homologues thereof
[0028] Another suitable class of synthetic lubricating oils comprises the
esters of
dicarboxylic acids (e.g., malonic acid, alkyl malonic acids, alkenyl malonic
acids, succinic
acid, alkyl succinic acids and alkenyl succinic acids, maleic acid, fumaric
acid, azelaic acid,
suberic acid, sebacic acid, adipic acid, linoleic acid dimer, phthalic acid)
with a variety of
alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl
alcohol, ethylene
glycol, diethylene glycol monoether, propylene glycol). Specific examples of
these 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.
[0029] Esters useful as synthetic oils also include those made from C5 to
C12
monocarboxylic acids and polyols, and polyol ethers such as neopentyl glycol,
trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.
[0030] The base oil may be derived from Fischer-Tropsch synthesized
hydrocarbons.
Fischer-Tropsch synthesized hydrocarbons are made from synthesis gas
containing H2 and CO
using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further
processing in
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order to be useful as the base oil. For example, the hydrocarbons may be
hydroisomerized;
hydrocracked and hydroisomerized; dewaxed; or hydroisomerized and dewaxed;
using
processes known to those skilled in the art.
[0031] Unrefined, refined and re-refined oils can be used in the present
lubricating oil
composition. Unrefined oils are those obtained directly from a natural or
synthetic source
without further purification treatment. For example, a shale oil obtained
directly from retorting
operations, a petroleum oil obtained directly from distillation or ester oil
obtained directly from
an esterification process and used without further treatment would be
unrefined oil. 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. Many such purification
techniques, such
as distillation, solvent extraction, acid or base extraction, filtration and
percolation are known
to those skilled in the art.
[0032] Re-refined oils are obtained by processes similar to those used to
obtain refined
oils applied to refined oils which have been already used in service. Such re-
refined oils are
also known as reclaimed or reprocessed oils and often are additionally
processed by techniques
for approval of spent additive and oil breakdown products.
[0033] Hence, the base oil which may be used to make the present
lubricating oil
composition may be selected from any of the base oils in Groups I-V as
specified in the
American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API
Publication
1509). Such base oil groups are summarized in Table 1 below:
Table 1
Base Oil Properties
Group(a) Saturates(b), wt. % Sulfur(o, wt. %
Viscosity Index'
Group I <90 and/or >0.03 80 to <120
Group II >90 <0.03 80 to <120
Group III >90 <0.03 >120
Group IV Polyalphaolefins (PA0s)
Group V All other base stocks not included in Groups I, II, III or
IV
(a) Groups I-III are mineral oil base stocks.
(b) Determined in accordance with ASTM D2007.
(c) Determined in accordance with ASTM D2622, ASTM D3120, ASTM D4294 or ASTM
D4927.
(d) Determined in accordance with ASTM D2270.
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[0034] Base oils suitable for use herein are any of the variety
corresponding to API
Group II, Group III, Group IV, and Group V oils and combinations thereof,
preferably the
Group III to Group V oils due to their exceptional volatility, stability,
viscometric and
cleanliness features.
[0035] The oil of lubricating viscosity for use in the lubricating oil
compositions of this
disclosure, also referred to as a base oil, is typically present in a major
amount, e.g., an amount
of greater than 50 wt. %, preferably greater than about 70 wt. %, more
preferably from about
80 to about 99.5 wt. % and most preferably from about 85 to about 98 wt. %,
based on the total
weight of the composition. The expression "base oil" as used herein shall be
understood to
mean a base stock or blend of base stocks which is a lubricant component that
is produced by
a single manufacturer to the same specifications (independent of feed source
or manufacturer's
location); that meets the same manufacturer's specification; and that is
identified by a unique
formula, product identification number, or both. The base oil for use herein
can be any presently
known or later-discovered oil of lubricating viscosity used in formulating
lubricating oil
compositions for any and all such applications, e.g., engine oils, marine
cylinder oils, functional
fluids such as hydraulic oils, gear oils, transmission fluids, etc.
Additionally, the base oils for
use herein can optionally contain viscosity index improvers, e.g., polymeric
alkylmethacrylates; olefinic copolymers, e.g., an ethylene-propylene copolymer
or a styrene-
butadiene copolymer; and the like and mixtures thereof.
[0036] As one skilled in the art would readily appreciate, the viscosity
of the base oil
is dependent upon the application. Accordingly, the viscosity of a base oil
for use herein will
ordinarily range from about 2 to about 2000 centistokes (cSt) at 100
Centigrade (C.).
Generally, individually the base oils used as engine oils will have a
kinematic viscosity range
at 100 C. of about 2 cSt to about 30 cSt, preferably about 3 cSt to about 16
cSt, and most
preferably about 4 cSt to about 12 cSt and will be selected or blended
depending on the desired
end use and the additives in the finished oil to give the desired grade of
engine oil, e.g., a
lubricating oil composition having an SAE Viscosity Grade of OW, OW-8, OW-12,
OW-16, OW-
20, OW-26, OW-30, OW-40, 0W-50, OW-60, 5W, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60,
10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W, 15W-20, 15W-30, 15W-40, 20, 30, 40,
50
and the like. Also, oils could be blended in viscosity grades specific to
tractor hydraulic fluids
such as J20C and/or J20D.
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Low Overbased (LOB) Sulfonate Deter2ent
[0037] The compositions described herein comprise low overbased alkaryl
sulfonate
salts. In particular, the compositions comprise:
(i) at least one low overbased alkaryl sulfonate calcium salt wherein the
alkaryl
group is an aryl group substituted with an alkyl group derived from propylene
or isobutylene oligomers; and / or
(ii) at least one low overbased alkaryl sulfonate calcium salt, wherein the
alkaryl
group is an aryl group substituted with an alkyl group derived from at least
one normal alpha olefin or an isomerized normal alpha olefin, said olefin
having from about 18 to about 30 carbon atoms.
These low overbased alkaryl sulfonate calcium salts can serve, e.g., as
detergents and
friction providers in the compositions described herein.
[0038] In some embodiments, the low overbased alkaryl sulfonate detergent
is derived
from an alkali metal, an alkaline earth metal, or mixtures thereof.
[0039] In some embodiments, the at least one low overbased alkaryl
sulfonate
calcium salt having an alkaryl group that is an aryl group substituted with an
alkyl group
derived from propylene or isobutylene oligomers has the following formula A:
Rx Rx Rx
¨SO3- ca 2+ -SO3- Ca2+ 03S-
- [CaCO3],
R -2 -n
or - (A)
wherein R is an alkyl group derived from propylene or isobutylene oligomers;
Rx is hydrogen or methyl, m is 0 to 5; and n is 1 or greater.
In some embodiments, m is 0.1-5. In some embodiments, n is 1. In some
embodiments, the
alkyl group has 3-36, 9-27, or 15-18 carbons. In some embodiments, the alkyl
group is
derived from propylene oligomers.
[0040] In some embodiments, the at least one low overbased alkaryl
sulfonate
calcium salt having an alkaryl group that is an aryl group substituted with an
alkyl group
derived from at least one normal alpha olefin or an isomerized normal alpha
olefin, said
olefin having from about 18 to about 30 carbon atoms, has the following
structure B:
Rx Rx
[ij-SO3 Ca2+ ¨SO3- Ca 2+ [CaCO3],
R -2 -n
or - (B)
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wherein R is an alkyl group derived from at least one normal alpha olefin or
an isomerized
normal alpha olefin, said olefin having from about 18 to about 30 carbon
atoms;
Rx is hydrogen or methyl, m is 0 to 5; and n is 1 or greater.
In some embodiments, m is 0.1-5. In some embodiments, n is 1.
[0041] In some embodiments, each of the low overbased alkaryl sulfonate
calcium
salts (A) or (B) above is a low overbased alkyl-substituted benzene or low
overbased alkyl-
substituted toluene sulfonate calcium salt.
[0042] The calcium content accounted for by the at least one low overbased
alkaryl
sulfonate calcium salt (A) or (B) present in the oil composition is 0.001 to
0.1 weight percent
of the lubricating oil composition. In some embodiments, the calcium content
is 0.01 to 0.09,
0.01 to 0.08, 0.01 to 0.07, or 0.01 to 0.06, 0.01 to 0.05, 0.01 to 0.04, 0.01
to 0.03, 0.01 to 0.02
weight percent of the lubricating oil.
[0043] In some embodiments, the low overbased alkaryl sulfonate calcium
salt (B) is
one wherein the alkaryl group is an aryl group substituted with an alkyl group
derived from at
least one normal alpha olefin or an isomerized normal alpha olefin, said
olefin having from
about 20 to about 24 carbon atoms.
[0044] In some embodiments, each or both of the alkaryl sulfonate calcium
salts (A)
or (B) is low overbased, wherein the TBN is less than 150, less than 140, less
than 130, less
than 120, less than 110, less than 100, less than 90, less than 80, less than
70, less than 60,
less than 50, less than 40, less than 30, less than 20, or less than 10. In
some embodiments,
each or both of the alkyaryl sulfonate calcium salts (A) or (B) has a TBN of 2-
100, 2-80, or
2-60.
Hi2h Overbased (HOB) Sulfonate Deter2ent
[0045] The lubricating oil composition of the present invention can
contain one or
more high overbased sulfonate detergents having a TBN of 300-800, 400-800, 400-
700, 450-
700, 500-700, 500-700, 500-600 mg KOH/g on an actives basis.
[0046] 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. 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
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carbon atoms, preferably about 16 to 30 carbon atoms, and more preferably 20-
24 carbon atoms
per alkyl substituted aromatic moiety.
[0047] In some embodiments, the high overbased detergent is a high
overbased
alkaryl sulfonate calcium detergent. In some embodiments, the calcium content
of the high
overbased detergent is 0.001 to 2.0, 0.01 1.0, 0.01 to 0.90, 0.01 to 0.70,
0.01 to 0.50, 0.01 to
0.40, 0.01 to 0.30; 0.01 to 0.20, 0.01 to 0.17 weight percent of the
lubricating oil
composition.
Hi2h Overbased (HOB) Phenate Deter2ent
[0048] In one aspect of the present disclosure, the high overbased phenate
detergent is
a phenolic-based detergent. In another aspect of the present disclosure, the
phenolic-based
detergent is an isomerized olefin phenate detergent.
[0049] In one aspect of the present disclosure, the high overbased phenate
detergent
has a TBN of 300-600, 300-500,300-450, 300- 400, 325-425, 350-425, 350-400
mgKOH/gram on an oil free basis.
[0050] In one aspect of the present disclosure, the phenolic-based
detergent is an
alkylated phenate detergent wherein the alkyl group is derived from an
isomerized normal
alpha olefin having from about 10 to about 40 carbon atoms per molecule.
[0051] In one aspect of the present disclosure, the phenolic-based
detergent has an
isomerization level (I) of the normal alpha olefin is between from about 0.10
to about 0.40,
preferably from about 0.10 to about 0.30, preferably from about 0.12 to about
0.30, and more
preferably from about 0.22 to about 0.30.
[0052] In one aspect of the present disclosure, the phenate detergent is a
sulfurized
phenate detergent.
[0053] In one aspect of the present disclosure, the isomerized olefin
phenate detergent
can be prepared as described in US Patent 8,580,717 which is herein
incorporated in its
entirety.
[0054] In one aspect of the present disclosure, the alkyl group is derived
from an
isomerized alpha olefin having from about 14 to about 30, from about 16 to
about 30, from
about 18 to about 30, from about 20 to about 28, 20 to about 24, or from about
18 to about 28
carbon atoms per molecule.
[0055] In another embodiment, the isomerization level of the alpha olefin
is about
0.26, and having from about 20 to about 24 carbon atoms.
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[0056] in some embodiments, the calcium content of the high overbased
phenate
detergent is from 0.005 to 0.08, 0.01 to 0.08, 0.01 to 0.07, 0.01 to 0.06,
0.01 to 0.05, 0.01 to
0.045 weight percent, based on the weight of the oil composition.
Other Detergents
[0057] Other detergents that may be used include oil-soluble overbased
sulfonate, salixarate,
salicylate, saligenm, complex detergents and naphthenate detergents and other
oil-soluble
alkylhydroxybenzoates 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.
[0058] Overbased metal detergents are generally produced by carbonating a
mixture
of hydrocarbons, detergent acid, for example: sulfonic acid,
alkylhydroxybenzoate etc., metal
oxide or hydroxides (for example calcium oxide or calcium hydroxide) and
promoters such as
xylene, methanol and water. For example, for preparing an overbased calcium
sulfonate, in
carbonation, the calcium oxide or hydroxide reacts with the gaseous carbon
dioxide to form
calcium carbonate. The sulfonic acid is neutralized with an excess of CaO or
Ca(OH)2, to
form the sulfonate.
[0059] Overbased detergents may be low overbased, e.g., an overbased salt
having a
TBN below 100 on an actives basis. In one embodiment, the TBN of a low
overbased salt
may be from about 30 to about 100. In another embodiment, the TBN of a low
overbased salt
may be from about 30 to about 80. Overbased detergents may be medium
overbased, e.g., an
overbased salt having a TBN from about 100 to about 250. In one embodiment,
the TBN of a
medium overbased salt may be from about 100 to about 200. In another
embodiment, the
TBN of a medium overbased salt may be from about 125 to about 175. Overbased
detergents
may be high overbased, e.g., an overbased salt having a TBN above 250. In one
embodiment, the TBN of a high overbased salt may be from about 250 to about
800 on an
actives basis.
[0060] In one embodiment, the detergent can be one or more alkali or
alkaline earth
metal salts of an alkyl-substituted hydroxyaromatic carboxylic acid. Suitable
hydroxyaromatic compounds include mononuclear monohydroxy and polyhydroxy
aromatic
hydrocarbons having 1 to 4, and preferably 1 to 3, hydroxyl groups. Suitable
hydroxyaromatic compounds include phenol, catechol, resorcinol, hydroquinone,
pyrogallol,
cresol, and the like. The preferred hydroxyaromatic compound is phenol.
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[0061] The alkyl substituted moiety of the alkali or alkaline earth metal
salt of an
alkyl-substituted hydroxyaromatic carboxylic acid is derived from an alpha
olefin having
from about 10 to about 80 carbon atoms. The olefins employed may be linear,
isomerized
linear, branched or partially branched linear. The olefin may be a mixture of
linear olefins, a
mixture of isomerized linear olefins, a mixture of branched olefins, a mixture
of partially
branched linear or a mixture of any of the foregoing.
[0062] In one embodiment, the mixture of linear olefins that may be used
is a mixture
of normal alpha olefins selected from olefins having from about 10 to about 40
carbon atoms
per molecule. In one embodiment, the normal alpha olefins are isomerized using
at least one
of a solid or liquid catalyst.
[0063] In one embodiment, at least about 50 mole%, at least about 75
mole%, at least
about 80 mole%, at least about 85 mole%, at least about 90 mole%, at least
about 95 mole%
of the alkyl groups contained within the alkali or alkaline earth metal salt
of an alkyl-
substituted hydroxyaromatic carboxylic acid such as the alkyl groups of an
alkaline earth
metal salt of an alkyl-substituted hydroxybenzoic acid detergent are a Czo or
higher. In
another embodiment, the alkali or alkaline earth metal salt of an alkyl-
substituted
hydroxyaromatic carboxylic acid is an alkali or alkaline earth metal salt of
an alkyl-
substituted hydroxybenzoic acid that is derived from an alkyl-substituted
hydroxybenzoic
acid in which the alkyl groups are Czo to about C28 normal alpha-olefins. In
another
embodiment, the alkyl group is derived from at least two alkylated phenols.
The alkyl group
on at least one of the at least two alkyl phenols is derived from an
isomerized alpha olefin.
The alkyl group on the second alkyl phenol may be derived from branched or
partially
branched olefins, highly isomerized olefins or mixtures thereof.
[0064] In another embodiment, the alkali or alkaline earth metal salt of
an alkyl-
substituted hydroxyaromatic carboxylic acid is a salicylate derived from an
alkyl group with
20-40 carbon atoms, preferably 20-28 carbon atoms, more preferably, isomerized
20-24 NAO.
Antiwear Agents
[0065] The lubricating oil composition disclosed herein can comprise one
or more
antiwear agent. Antiwear agents reduce wear of metal parts. Suitable anti-wear
agents include
dihydrocarbyl dithiophosphate metal salts such as zinc dihydrocarbyl
dithiophosphates
(ZDDP) of formula (Formula 1):
Zn[S¨P(=S)(OR')(0R2)12 Formula 1,
wherein IV and R2 may be the same of different hydrocarbyl radicals having
from 1 to
18 (e.g., 2 to 12) carbon atoms and including radicals such as alkyl, alkenyl,
aryl, arylalkyl,
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alkaryl and cycloaliphatic radicals. Particularly preferred as 12.' and R2
groups are alkyl groups
having from 2 to 8 carbon atoms (e.g., the alkyl radicals may be ethyl, n-
propyl, isopropyl, n-
butyl, isobutyl, sec-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, 2-
ethylhexyl). In order to
obtain oil solubility, the total number of carbon atoms (i.e., Ri+R2) will be
at least 5. The zinc
dihydrocarbyl dithiophosphate can therefore comprise zinc dialkyl
dithiophosphates. The zinc
dialkyl dithiophosphate is a primary, secondary zinc dialkyl dithiophosphate,
or a combination
thereof.ZDDP may be present at 3 wt. % or less (e.g., 0.1 to 1.5 wt. %, or 0.5
to 1.0 wt %) of
the lubricating oil composition.
Antioxidants
[0066] The
lubricating oil composition disclosed herein can comprise one or more
antioxidant. Antioxidants reduce the tendency of mineral oils during to
deteriorate during
service. Oxidative deterioration can be evidenced by sludge in the lubricant,
varnish-like
deposits on the metal surfaces, and by viscosity growth. Suitable antioxidants
include hindered
phenols, aromatic amines, hindered amines (also known as HALS-Hindered Amine
light
Stabilizers) and sulfurized alkylphenols and alkali and alkaline earth metals
salts thereof
[0067] The
hindered amines used in this invention are of many types, with three types
predominating: pyrimidines, piperidines and stable nitroxide compounds. Many
more are
described in the book "Nitrones, Nitronates, and Nitroxides", E. Breuer, et
al., 1989, John
Wiley & Sons and in Patents such as US9315760.
[0068] The
hindered phenol antioxidant often contains a secondary butyl and/or a
tertiary butyl group as a sterically hindering group. The phenol group may be
further substituted
with a hydrocarbyl group (typically linear or branched alkyl) and/or a
bridging group linking
to a second aromatic group. Examples of suitable hindered phenol antioxidants
include 2,6-di-
tert-butylphenol; 4-methyl-2,6-di-tert-butylphenol; 4-ethyl-2,6-di-tert-
butylphenol; 4-propy1-
2,6-di-tert-butylphenol; 4-butyl-2,6-di-tert-
butylphenol; and 4-dodecy1-2,6-di-tert-
butylphenol. Other useful hindered phenol antioxidants include 2,6-di-alkyl-
phenolic propionic
ester derivatives such as IRGANOX L-135 from Ciba and bis-phenolic
antioxidants such as
4,4'-bis(2,6-di-tert-butylphenol) and 4,4'-methylenebis(2,6-di-tert-
butylphenol).
Typical aromatic amine antioxidants have at least two aromatic groups attached
directly to one
amine nitrogen. Typical aromatic amine antioxidants have alkyl substituent
groups of at least
6 carbon atoms. Particular examples of aromatic amine antioxidants useful
herein include 4,4'-
dioctyldiphenylamine, 4,4'-dinonyldiphenylamine, N-phenyl-l-naphthylamine, N-
(4-tert-
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octypheny1)-1-naphthylamine, and N-(4-octylpheny1)-1-naphthylamine.
Antioxidants may be
present at 0.01 to 5 wt. % (e.g., 0.1 to 2 wt. %) of the lubricating oil
composition.
Dispersants
[0069] The lubricating oil composition disclosed herein can comprise one
or more
dispersant. Dispersants maintain in suspension materials resulting from
oxidation that are
insoluble in oil, thus preventing sludge flocculation and precipitation or
deposition on metal
parts. Dispersants useful herein include nitrogen-containing, ashless (metal-
free) dispersants
known to effective to reduce formation of deposits upon use in gasoline and
diesel engines.
[0070] Suitable dispersants include hydrocarbyl succinimides, hydrocarbyl
succinamides, mixed ester/amides of hydrocarbyl-substituted succinic acid,
hydroxyesters of
hydrocarbyl-substituted succinic acid, and Mannich condensation products of
hydrocarbyl-
substituted phenols, formaldehyde and polyamines. Also suitable are
condensation products of
polyamines and hydrocarbyl-substituted phenyl acids. Mixtures of these
dispersants can also
be used.Basic nitrogen-containing ashless dispersants are well-known
lubricating oil additives
and methods for their preparation are extensively described in the patent
literature. Preferred
dispersants are the alkenyl succinimides and succinamides where the alkenyl-
substituent is a
long-chain of preferably greater than 40 carbon atoms. These materials are
readily made by
reacting a hydrocarbyl-substituted dicarboxylic acid material with a molecule
containing amine
functionality. Examples of suitable amines are polyamines such as polyalkylene
polyamines,
hydroxy-substituted polyamines and polyoxyalkylene polyamines.
[0071] Particularly preferred ashless dispersants are the polyisobutenyl
succinimides
formed from polyisobutenyl succinic anhydride and a polyalkylene polyamine
such as a
polyethylene polyamine of formula 2:
NH2( CH2 CH2NH)zH Formula 2,
wherein z is 1 to 11. The polyisobutenyl group is derived from polyisobutene
and preferably
has a number average molecular weight (Mn) in a range of 700 to 3000 Daltons
(e.g., 900 to
2500 Daltons). For example, the polyisobutenyl succinimide may be a mono-
succinimide or a
bis-succinimide derived from a polyisobutenyl group having a Mn of 900 to 2500
Daltons. As
is known in the art, the dispersants may be post-treated (e.g., with a
boronating agent or a cyclic
carbonate, ethylene carbonate etc).
[0072] Nitrogen-containing ashless (metal-free) dispersants are basic, and
contribute to
the TBN of a lubricating oil composition to which they are added, without
introducing
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additional sulfated ash.Dispersants may be present at 0.1 to 10 wt. % (e.g., 2
to 5 wt. %) of the
lubricating oil composition.
Foam Inhibitors
[0073] The lubricating oil composition disclosed herein can comprise one
or more
foam inhibitor that can break up foams in oils. Non-limiting examples of
suitable foam
inhibitors or anti-foam inhibitors include silicone oils or
polydimethylsiloxanes,
fluorosilicones, alkoxylated aliphatic acids, polyethers (e.g., polyethylene
glycols), branched
polyvinyl ethers, alkyl acrylate polymers, alkyl methacrylate polymers,
polyalkoxyamines and
combinations thereof
Additional Co-Additives
[0074] The lubricating oil compositions of the present disclosure may also
contain
other conventional additives that can impart or improve any desirable property
of the
lubricating oil composition in which these additives are dispersed or
dissolved. Any additive
known to a person of ordinary skill in the art may be used in the lubricating
oil compositions
disclosed herein. Some suitable additives have been described in Mortier et
al., "Chemistry and
Technology of Lubricants", 2nd Edition, London, Springer, (1996); and Leslie
R. Rudnick,
"Lubricant Additives: Chemistry and Applications", New York, Marcel Dekker
(2003), both
of which are incorporated herein by reference. For example, the lubricating
oil compositions
can be blended with antioxidants, anti-wear agents, detergents such as metal
detergents, rust
inhibitors, dehazing agents, demulsifying agents, metal deactivating agents,
friction modifiers,
pour point depressants, antifoaming agents, co-solvents, corrosion-inhibitors,
ashless
dispersants, multifunctional agents, dyes, extreme pressure agents and the
like and mixtures
thereof A variety of the additives are known and commercially available. These
additives, or
their analogous compounds, can be employed for the preparation of the
lubricating oil
compositions of the disclosure by the usual blending procedures.
[0075] In the preparation of lubricating oil formulations, it is common
practice to
introduce the additives in the form of 10 to 100 wt. % active ingredient
concentrates in
hydrocarbon oil, e.g. mineral lubricating oil, or other suitable solvent.
[0076] Usually these concentrates may be diluted with 3 to 100, e.g., 5 to
40, parts by
weight of lubricating oil per part by weight of the additive package in
forming finished
lubricants, e.g. tractor hydraulic fluids. The purpose of concentrates, of
course, is to make the
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handling of the various materials less difficult and awkward as well as to
facilitate solution or
dispersion in the final blend.
[0077] Each of the foregoing additives, when used, is used at a
functionally effective
amount to impart the desired properties to the lubricant. Thus, for example,
if an additive is a
friction modifier, a functionally effective amount of this friction modifier
would be an amount
sufficient to impart the desired friction modifying characteristics to the
lubricant.
[0078] In general, the concentration of each of the additives in the
lubricating oil
composition, when used, may range from about 0.001 wt. % to about 20 wt. %,
from about
0.01 wt. % to about 15 wt. %, or from about 0.1 wt. % to about 10 wt. %, from
about 0.005
wt.% to about 5 wt.%, or from about 0.1 wt.% to about 2.5 wt.%, based on the
total weight of
the lubricating oil composition. Further, the total amount of the additives in
the lubricating oil
composition may range from about 0.001 wt.% to about 20 wt.%, from about 0.01
wt.% to
about 10 wt.%, or from about 0.1 wt.% to about 5 wt.%, based on the total
weight of the
lubricating oil composition.
[0079] The following examples are presented to exemplify embodiments of
the
invention but are not intended to limit the invention to the specific
embodiments set forth.
Unless indicated to the contrary, all parts and percentages are by weight. All
numerical
values are approximate. When numerical ranges are given, it should be
understood that
embodiments outside the stated ranges may still fall within the scope of the
invention.
Specific details described in each example should not be construed as
necessary features of
the invention.
EXAMPLES
The following examples are intended for illustrative purposes only and do not
limit in any way
the scope of the present disclosure.
Isomerization level (I) and NMR method
[0080] The isomerization level (I) of the olefin was determined by
hydrogen-1 (1H)
NMR. The NMR spectra were obtained on a Bruker Ultrashield Plus 400 in
chloroform-dl at
400 MHz using TopSpin 3.2 spectral processing software.
[0081] The isomerization level (I) represents the relative amount of
methyl groups (-
CH3) (chemical shift 0.3-1.01 ppm) attached to the methylene backbone groups (-
CH2-)
(chemical shift 1.01-1.38 ppm) and is defined by Equation (1) as shown below,
I = m/(m+n) Equation (I)
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where m is NMR integral for methyl groups with chemical shifts between 0.3
0.03 to 1.01
0.03 ppm, and n is NMR integral for methylene groups with chemical shifts
between 1.01
0.03 to 1.38 0.10 ppm.
[0082] The isomerized level (I) of the alpha olefin is between from about
0.1 to about
0.4, preferably from about 0.1 to about 0.3, more preferably from about 0.12
to about 0.3.
[0083] In one embodiment, the isomerization level of the NAO is about
0.16, and
having from about 20 to about 24 carbon atoms.
[0084] In another embodiment, the isomerization level of the NAO is about
0.26, and
having from about 20 to about 24 carbon atoms.
[0085] Provided herein are Tractor Hydraulic Fluid Compositions which are
envisioned for the present disclosure. Examples of the disclosure will
generally include test
formulations disclosed in Table 2 below.
TABLE 2: TEST COMPOSITIONS
Description Wt. %
LOB Sulfonate 0.001 to 5.0
HOB Sulfonate 0.001 to 5.0
HOB Phenate 0.001 to 5.0
Other Additives (Example: Dispersants, Other Detergents, 0.01 to 30
Antioxidants, Viscosity Improvers, Wear Inhibitors, Foam
Inhibitors, Friction Modifiers, etc.)
Base Oils 0.1 to 99.9
[0086] Examples of the disclosure will generally include test formulations
disclosed in
Table 3 below.
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Table 3: Formulation Compositions
Ex 1 Comp A Ex 2 Comp B Ex 3 Comp C
Phenate 1 (wt. 0.012 0 0.020 0 0.040 0
% Ca)
Phenate 2 (wt. 0 0.012 0 0.020 0 0.040
% Ca)
LOB sulfonate 0.024 0.024 0.024 0.024 0.024 0.024
(wt. % Ca)
HOB sulfonate 0.240 0.240 0.240 0.240 0.240 0.240
(wt. % Ca)
Friction 0.75 0.75 0.75 0.75 0.75 0.75
Modifier (wt%)
ZnDTP (mM) 15 15 15 15 15 15
Foam inhibitor 0.02 0.02 0.02 0.02 0.02 0.02
(wt%)
Dispersant 4.22 4.22 4.22 4.22 4.22 4.22
PMA (wt%)
PPD (wt%) 0.2 0.2 0.2 0.2 0.2 0.2
Base oil (wt%) 11.42 11.42 11.45 11.47 11.45 11.45
Phenate 1 is Ca phenate derived from C20-24 isomerized olefin
Phenate 2 is Ca phenate derived from tetrapropylene
[0087]
The test formulations in Table 3 were evaluated in the R20 test which is an
axle brake
screener test. It is a friction endurance test that tracks friction
coefficients and brake noise at
various friction plate engagement steps that include multiple pressures and
speeds. This test is
part of the ZF TE-ML 05E and TE-ML 05F specifications for axles of off-road
vehicles from
ZF Friedrichshafen AG, Friedrichshafen, Germany, and is available there.
[0088] The results of the R20 test are in Table 4 below.
Table 4: Max Torque Variation at Various Facing Pressure (MPa)
MPa Ex 1 Comp A Ex 2 Comp B Ex 3 Comp C
1.0 836.03 1016.85 921.59 1032.88 436.73 536.66
1.5 1154.23 1293.91 1128.87 1210.25 441.63 676.45
2.0 1183.84 1430.68 1069.86 1311.69 441.26 704.81
2.5 1269.61 1551.67 1191.98 1408.00 438.54 757.37
3.0 1387.19 1586.69 1080.82 1459.35 182.45 698.06
3.5 1316.18 1398.84 378.19 1479.77 87.71 309.99
4.0 656.43 1476.73 419.93 871.95 74.80 102.41
[0089]
The R20 friction testing was performed to compare the low speed brake torque
variation
performance of formulations containing Phenate 1 (Ca phenate derived from C20-
24
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isomerized olefin) versus analogous formulations containing Phenate 2 (Ca
phenate derived
from tetrapropylene). The results of R20 testing demonstrate that Example
formulations 1, 2
and 3 comprising Phenate 1 show reduced low speed brake torque variation as
compared to
Comparative formulations A, B, and C comprising Phenate 2. This means that
formulations
containing phenate 1 improved clutch and brake capacity while maintaining low
torque
variation at low speed. The benefit of mitigated low speed brake torque
variation is decreased
energy loss and vibration, which correlates to lower risk of damage to
mechanical parts,
decreased operator discomfort, and less tendency for brake noise.
19
