U.S. patent application number 12/961624 was filed with the patent office on 2011-05-12 for lubricating fluids.
This patent application is currently assigned to THE LUBRIZOL CORPORATION. Invention is credited to Ellen B. Brandes, Halou Oumar-Mahamat, William T. Sullivan, Shi-Ming Wu.
Application Number | 20110111992 12/961624 |
Document ID | / |
Family ID | 43974637 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110111992 |
Kind Code |
A1 |
Sullivan; William T. ; et
al. |
May 12, 2011 |
LUBRICATING FLUIDS
Abstract
The invention concerns a fully formulated lubricating fluid or
grease comprising an additive package and a major amount of base
oil, the improvement comprising the substantial absence of low
molecular weight primary, secondary, tertiary, cyclic aliphatic
mono or polyamines of 30 carbons or less and the absence of the
corresponding acid phosphate amine salts in said fully formulated
lubricating fluid.
Inventors: |
Sullivan; William T.;
(Brick, NJ) ; Oumar-Mahamat; Halou; (Belle Mead,
NJ) ; Wu; Shi-Ming; (Dayton, NJ) ; Brandes;
Ellen B.; (Hampton, NJ) |
Assignee: |
THE LUBRIZOL CORPORATION
Wickliffe
OH
|
Family ID: |
43974637 |
Appl. No.: |
12/961624 |
Filed: |
December 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11333689 |
Jan 17, 2006 |
|
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12961624 |
|
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Current U.S.
Class: |
508/100 ;
508/186; 508/433 |
Current CPC
Class: |
C10N 2030/10 20130101;
C10M 2223/04 20130101; C10N 2030/36 20200501; C10N 2040/04
20130101; C10N 2030/04 20130101; C10M 2219/106 20130101; C10N
2030/52 20200501; C10M 137/04 20130101; C10N 2030/08 20130101; C10N
2030/02 20130101 |
Class at
Publication: |
508/100 ;
508/433; 508/186 |
International
Class: |
C10M 137/04 20060101
C10M137/04 |
Claims
1.-36. (canceled)
37. In a fully formulated lubricating fluid including an effective
amount of an acid phosphate-containing antiwear additive,
characterized as comprising an additive package and a major amount
of at least one base oil, the improvement comprising the absence of
low molecular weight primary, secondary, tertiary, and cyclic
aliphatic amines of 30 carbons or less and the absence of the
corresponding acid phosphate amine salts, wherein said acid
phosphate is selected from at least one mono and/or dihydrocarbyl
ester of an acid phosphate characterized by the formula (1):
(R.sub.1O)(R.sub.2O)P(O)OH (1) where R.sub.1 is a hydrocarbyl group
and R.sub.2 is selected from hydrogen or a hydrocarbyl group.
38. The fully formulated lubricating fluid of claim 37, wherein
said additive package has a TBN<22.
39. The fully formulated lubricating fluid of claim 37, wherein
said additive package has a TBN<20.
40. The fully formulated lubricating fluid of claim 37, wherein
said additive package has a TBN<15.
41. The fully formulated lubricating fluid of claim 37, wherein
said additive package has a TBN<10.
42. The fully formulated lubricating fluid of claim 37, wherein
said additive package has a TBN<5.
43. The fully formulated lubricating fluid of claim 37, wherein the
hydrocarbyl groups of R.sub.1 and R.sub.2 are independently
selected from straight-chained or branched alkyl groups having from
1 to 20 carbon atoms.
44. The fully formulated lubricating fluid of claim 37, wherein the
hydrocarbyl groups of R.sub.1 and R.sub.2 are independently
selected from straight-chained or branched alkyl groups having from
2 to 20 carbon atoms.
45. The fully formulated lubricating fluid of claim 37, wherein the
hydrocarbyl groups of R.sub.1 and R.sub.2 are independently
selected from straight-chained or branched alkyl groups having from
3 to 20 carbon atoms.
46. The fully formulated lubricating fluid of claim 37, wherein at
least one of R.sub.1 and R.sub.2 is 2-ethylhexyl.
47. The fully formulated lubricating fluid of claim 37, further
characterized as comprising at least one of the following
ingredients: (a) at least one sulfur-containing extreme pressure
agent; (b) at least one nitrogen-containing dispersant; (c) at
least one corrosion inhibitor.
48. The additive package of claim 47, characterized as comprising
at least two of the ingredients (a)-(c).
49. The additive package of claim 47, characterized as comprising
ingredients (a)-(c).
50. The fully formulated lubricating fluid of claim 47, further
comprising at least one ingredient selected from the group
consisting of borated dispersants, non-aminic rust inhibitors,
defoamants, pour point depressants, antioxidants, demulsifiers,
friction modifiers, seal swell agents, chromophores, deodorants,
limited slip additives, detergents, VI modifiers, and
tackifiers.
51. The fully formulated lubricating fluid of claim 37, further
characterized by a major amount of at least one base oil selected
from API Groups I to V.
52. The fully formulated lubricating fluid of claim 51, further
comprising at least one additive selected from the group consisting
of borated dispersants, non-aminic rust inhibitors, defoamants,
pour point depressants, antioxidants, demulsifiers, friction
modifiers, seal swell agents, chromophores, deodorants, limited
slip additives, detergents, VI modifiers, and tackifiers.
53. The fully formulated lubricating fluid of claim 37, further
characterized by at least one of the following criterion: (a) rated
1a or 1b according to the Copper Corrosion test according to ASTM
D130; (b) passing the Four Ball Weld test according to ASTM D2783
with a Weld Point of 250 kg minimum and a Load Wear Index of 45 kg
minimum; (c) passing the Rust Test, Part A and Part B, according to
ASTM D665; (d) having a value of at least 9.0 or greater in the L33
test, run according to ASTM D7038.
54. The fully formulated lubricating fluid of claim 53,
characterized by a value of at least 9.0 or greater in the L33
test, run according to ASTM D7038.
55. An apparatus comprising at least one seal and a lubricating
fluid according to claim 37 in contact with said seal.
56. The apparatus of claim 55, wherein said seal comprises at least
one material selected from fluoroelastomers, nitriles, and
polyacrylates.
57. An apparatus including a fully formulated fluid according to
claim 1, wherein said apparatus comprises at least one of the
following: a hypoid axle, a mechanical steering drive or gear box,
a planetary hub reduction axle or gear box, a transfer gear box, a
synchromesh gear box, a power take-off gear, or a limited slip
axle.
58. A method for lubricating an apparatus, the method comprising
applying a lubricant to the apparatus wherein said lubricant
comprises a base oil, an effective amount of an acid
phosphate-containing antiwear additive, said lubricant further
characterized as essentially free of primary, secondary, tertiary
and cyclic hydrocarbyl amines with a carbon number of C30 or less
and the corresponding salts of said acid phosphate, wherein said
acid phosphate is selected from at least one mono and/or
dihydrocarbyl ester of an acid phosphate characterized by the
formula (1): (R.sub.1O)(R.sub.2O)P(O)OH (1) where R.sub.1 is a
hydrocarbyl group and R.sub.2 is selected from hydrogen or a
hydrocarbyl group.
59. A method of preparing a fully formulated lubricating fluid, the
method comprising the steps of combining a major amount of at least
one base oil and an additive package, the additive package
comprising an effective amount of an acid phosphate-containing
antiwear additive, wherein the additive package is selected to have
an absence of low molecular weight primary, secondary, tertiary,
and cyclic aliphatic amines of 30 carbons or less and the absence
of corresponding acid phosphate amine salts, wherein said acid
phosphate is selected from at least one mono and/or dihydrocarbyl
ester of an acid phosphate characterized by the formula (1):
(R.sub.1O)(R.sub.2O)P(O)OH (1) where R.sub.1 is a hydrocarbyl group
and R.sub.2 is selected from hydrogen or a hydrocarbyl group.
Description
FIELD OF THE INVENTION
[0001] The invention relates to lubricating fluids having
essentially no low molecular weight (C30 or less) primary,
secondary, tertiary or cyclic aliphatic amine to serve as a rust
inhibitor.
BACKGROUND OF THE INVENTION
[0002] Oxidative stability, seal compatibility, protection from
wear, and overall durability are highly sought after features of
gears oils for both automotive and industrial applications.
Original equipment manufacturers (OEMs) as well as the consuming
public are constantly demanding improvements such as extended drain
intervals from suppliers of gear oils.
[0003] Enhanced oxidative stability is highly desired in driveline
fluids (e.g., automotive transmissions and differentials) as well
as in gear boxes used for various industrial applications. When
oxidation is problematic, sludge and carbon/varnish deposits appear
on the gear surfaces, which may adversely impact the functioning of
the gears. Lubricants are expected to be able to pass lengthy
oxidation tests, e.g. the extended L-60-1 test (comprising a 200 hr
test for axle oils and 300 hr test for transmission oils). The
lubricant preferably should be able to provide adequate cleanliness
as well as viscosity control to pass these tests.
[0004] In order to prepare lubricants which are oxidatively stable,
it has become common practice to add antioxidants to the
lubricating oil, either phenolic or arylamine types. Alternatively,
formulators can choose to use certain base stocks and/or additive
combinations which are less prone to oxidation.
[0005] Gear oils that are expected to survive for long drain
intervals should be able to leave seals undamaged so that no
leakage occurs during the lifetime of the gear box. Axle and
transmission seal materials in the U.S. and Europe include
fluoroelastomer, nitrile and polyacrylate. Static and dynamic seal
testing in the U.S. and Europe are part of industry and OEM
performance specifications for both industrial and automotive gear
oil.
[0006] One important feature of a gear oil is its ability to
prevent surface distress, which if severe enough, can ultimately
lead to catastrophic failure of the gears. Gear distress or wear
can be in the form of pitting, spalling, ridging, rippling, etc.
for automotive gears, especially those in the differential because
of the loads. To control wear, it is common to add anti-wear
additives to reduce or prevent damage. These additives preferably
should be able to function at temperatures from sub-zero to
temperatures around 160.degree. C., which could be reached if the
vehicle is subjected to severe operating conditions. In addition,
to perform most effectively, anti-wear additives should be able to
function in the presence of other aggressive additives that perform
key functions, e.g. extreme pressure additives, and they preferably
should be able to continue to function for long operating
periods.
[0007] There are industry tests for examining the effectiveness of
antiwear additive systems. In the automotive industry, the L-37 is
most widely recognized. This rig test simulates low speed, high
torque operation. A low temperature modification of this test is
also part of the API GL-5 and SAE J2360 specification for 75 W
graded gear lubricants. The low temperature version of this test is
known as the Canadian version. There also exists a high temperature
version of the L-37 test, which is included in several OEM
specifications. In the L-37 test, and its variants, the gears are
disassembled at the end of the test and the gear distress is
rated.
[0008] Commonly used anti-wear additives are phosphorous containing
compounds. They usually include amine-neutralized salts of
phosphorus acids, phosphinyl acids, phosphonyl acids,
thiophosphorus acids, thiophosphinyl acids, thiophosphonyl acids,
and the partial esters of these. The amines useful in preparing the
amine salts are primary or secondary hydrocarbyl monoamines or
polyamines containing about 4-30 carbon atoms. They may also be
tertiary or cyclic amines. The most common amines are primary,
fatty amines containing 10-20 carbon atoms, like octadecyl amine or
tertiary alkyl amines like C12-C14 tertiary alkyl primary amine,
commercially available as "Primene 81-R." It is commonly believed
that the amine neutralization is a necessary feature of the
different phosphorus-containing compounds, because of its ability
to impart critically required steel corrosion protection and
thermal stability.
[0009] In order to reach the extended drain intervals that OEMs are
now seeking for their gear boxes and differentials, durability is
important for gear oils, both automotive and industrial. The
durability of a fluid will depend on the base oils that are being
used, e.g. synthetic base oils will be far more durable than API
Group I and II fluids because of the superior oxidative and thermal
stability. However, base oil selection is only part of the picture
for formulating gear oils with improved durability. The additive
system must also be carefully chosen so as to provide oxidation
stability, seal compatibility and antiwear performance, all of
which contribute to an oil's durability.
[0010] Industrial and automotive gear lubes perform in much the
same way, though loads on the industrial gears tend to be spread
out over larger surface areas and therefore are not as great as
those seen in the rear axle of an automotive vehicle. Nevertheless,
similar features would be considered desirable in both types of
gear oils. Durability, for example, is important as this would
equate to longer drain intervals and reduced down time and reduced
maintenance costs. Durability in the form of improved oxidative
stability, reduced wear and better seal compatibility are highly
desired for all types of gear oils.
[0011] Because there are numerous additives added to such
compositions for many diverse reasons and with each additive
interacting with all the other additives in some manner, it is
extremely difficult to find new formulations showing an improvement
in at least one property while having little or no detrimental
effects on other properties.
[0012] U.S. Pat. No. 6,844,300 and EP 1 233 051 A1 teach that a
gear oil comprising a base oil, a thermally stable P-containing
antiwear additive and a metal free sulfur EP agent, wherein the S
is present at least at a level of 10,000 ppms, and the P is present
from 100-350 ppms will meet GL-5 requirements. The thermally stable
antiwear additive is defined as oil soluble amine salts of
phosphoric acid esters as well as reaction products of
dicyclopentadiene and thiophosphoric acid. The salts may be formed
beforehand or in situ.
[0013] U.S. Pat. No. 6,046,144 describes synergistic antioxidant
compositions comprising amine salts of alkyl phosphates, and
ethylenediamine, ammonium or metal salts of
alkylarylsulfonates.
[0014] U.S. Pat. No. 5,942,470 teaches the use of combining at
least one oil soluble sulfur-containing extreme pressure or
antiwear agent with at least one oil soluble amine salt of a
partial ester of an acid of phosphorus and with at least one oil
soluble succinimide dispersant of a formula defined in the patent.
A lengthy list of many suitable amine salts of the partially
esterified phosphorus is included in the patent. Primary amines are
preferred.
[0015] U.S. Pat. No. 5,763,372 discusses "clean gear" boron-free
gear additive systems, which employ an ashless boron-free
dispersant, a sulfur source, and a phosphorus source, wherein at
least one is chosen from a group of oil-soluble amine salts of acid
phosphates.
[0016] U.S. Pat. No. 5,756,429 describes a composition suitable for
high speed gears having a peripheral speed of at least 10 m/sec
containing a base oil having a % Ca of 5 or less and a S, P, N
ratio of 100N/(S+P) between 4 and 10 by weight. Use of acid
phosphates and their amine salts are preferred. The composition is
said to be able to inhibit sludge and permit the prolongation of
the life of an oil seal.
[0017] U.S. Pat. No. 5,691,283 describes a transmission and axle or
differential gearing which comprises a base oil and a Mannich
dispersant, a sulfur-containing EP agent, a P- and N-containing
antiwear additive, and an overbased alkali or alkaline earth
carboxylate, sulphonate, or sulfurized phenate having a TBN (Total
Base Number) of at least 145.
[0018] U.S. Pat. No. 5,573,696 and U.S. Pat. No. 5,500,140 discuss
the preparation of amine-neutralized acid phosphates, which are
prepared by reacting P.sub.2O.sub.5 with an alcohol prepared from
the reaction of an epoxide with dihydrocarbyl phosphorothioic
acid.
[0019] U.S. Pat. No. 5,547,596 describes a lubricant composition
for the limited slip differential (LSD) of a car which is obtained
by adding a phosphate amine salt, such as an amine salt of an oleyl
acid phosphate and a borated ashless dispersant, such that the
ratio of N/P is 0.5-1.0; the ratio of NB is 4-10; the phosphorus
content is in the range of 0.15-0.4% by weight; and the boron
content is in the range of 0.01 to 0.04% by weight. This lubricant
composition inhibits the generation of chattering during the
operation of a LSD device and has excellent oxidative
stability.
[0020] U.S. Pat. No. 5,358,650, U.S. Pat. No. 5,571,445, and WO
94/22990 describe a synthetic fluid which includes a variety of
synthetic base oils plus specified amounts of the following: a
sulfur-containing extreme pressure-antiwear agent, a P-containing
antiwear agent, a corrosion inhibitor, an amine and/or carboxylic
acid rust inhibitor, a foam inhibitor, and an ashless
dispersant.
[0021] U.S. Pat. No. 5,354,484 describes how improved high
temperature stability can be achieved with the presence of at least
one soluble tertiary aliphatic primary amine salt, wherein the
primary amine contains 4-30 carbon atoms, at least one of which is
a substituted phosphoric acid, in combination with a borated
succinimide dispersant.
[0022] U.S. Pat. No. 5,328,619 describes an additive concentrate
comprising at least one oil soluble organic acid, e.g. one or more
hydrocarbyl phosphoric acids, one or more carboxylic acids or a
combination of the two, and a hydrocarbyl amine which is added such
that the pH of the finished concentrate is in the 6.0-7.0 range. A
borated dispersant is introduced into the concentrate being formed
when the concentrate is at least 6.0. The resulting compositions
are said to inhibit haze in the resulting concentrates, and the pH
control can provide gear compositions having enhanced extreme
pressure performance in the L-42 test, and improved rust in the
L-33 test.
[0023] U.S. Pat. No. 4,575,431 discusses the combination of
dihydrocarbyl hydrogen thiophosphates and hydrocarbyl dihydrogen
phosphates and dihydrocarbyl hydrogen phosphates, with the
phosphates being at least 50% neutralized with a hydrocarbyl amine
that is C10-C30.
[0024] U.S. Pat. No. 4,431,552 discusses a lubricating composition
having dispersed therein a hydrated alkali metal borate extreme
pressure agent and an effective amount of a mixture of a phosphate,
a monothiophosphate, and a dithiophosphate. All of the phosphates
are preferably used as their hydrocarbyl amine salts.
[0025] U.S. Pat. No. 4,118,328 discusses the preparation and use of
phosphate salts comprised of heating a triaryl phosphate and a
primary or secondary aliphatic amine in a 1-20 molar ratio,
respectively, with a trace amount of boric acid for catalyst.
[0026] U.S. Pat. No. 3,728,260 describes the preparation of a
neutral hydrocarbyl phosphate in combination with an alkyl amine
hydrocarbyl phosphate salt for improved load carrying.
[0027] EP 531 585 describes the use of an additive composition
which includes a borated Mannich dispersant, a sulfur containing
anti-wear or EP agent, a metal free phosphorus-containing
antiwear-EP agent, and an oil-soluble amine salt of a carboxylic
acid. Free amine may or may not be present, and may or may not be
complexed to the phosphorus antiwear agent.
[0028] EP 519 760 B1 teaches that an oil soluble amine is used to
adjust the pH of an additive concentrate to 6-7 then dispersant is
added after this adjustment is made.
[0029] EP 391 653 B1 and EP 450 208 B1 both discuss having high
concentrations of amines along with suitable quantities of weak
acids, e.g. carboxylic acids, in the presence of sulfurized
isobutylene and P-containing antiwear additives to provide gear
oils with improved gear performance based on the results of a
Planetary Spur Gear Test.
[0030] UK 2,108,147 examines the use of oil soluble overbased
sodium salts of phosphate esters in lubricant compositions.
[0031] WO 03/1004620 A2 discusses a lubricating composition with
improved efficiency for an emissions control system, wherein the
compositions contain a metal-containing detergent, a metal salt of
one or more phosphorus acids or the corresponding esters, and an
acylated nitrogen-containing compound having at least 10 carbon
atoms. The resulting TBN composition has a phosphorus concentration
of up to about 0.12%.
[0032] U.S. Pat. No. 4,900,460 covers sulfurized olefins reacted
with phosphates and phosphites. The reaction product is useful as
an extreme pressure and wear additive for lube compositions.
[0033] U.S. Pat. No. 3,513,093 describes a composition containing a
major part of a lubricating oil and minor portion of a substituted
polyamine, which is prepared by reacting a polyamine with a
succinic acid producing hydrocarbon having at least 50 carbons with
at least 0.001 moles of a phosphorus acid producing compound
selected from the class of phosphoric acids, phosphorus acids,
phosphonyl acids, phosphinyl acids, etc. These species were found
to give improved oxidation performance in a variety of bench and
engine tests.
[0034] U.S. Pat. No. 2,224,695 teaches the preparation of a
corrosion inhibitor for metals which comprises an ester of an acid
of phosphorus having at least one of the hydrogen atoms of the acid
replaced by an ester group and at least one of the hydrogen atoms
replaced by an inorganic radical, upon exposing it to a metal
surface. Under favorable conditions, it reacts chemically with
metal surfaces to form a protective coating and inhibit corrosive
wear.
[0035] EP 531 000 B1 discusses an additive composition containing
a.) a reaction product of a phosphorus or thiophosphorus acid with
an ashless dispersant and a boron compound and b.) a sulfur
containing antiwear-EP agent. The gear oil prepared with these
components is said to have these performance improvements: 1.)
inhibition of scoring/scuffing, 2.) improved wear in the form of
ridging, rippling, pitting and spalling, 3.) improved oxidation in
the form of reduced sludge and varnish deposits, especially at
higher temperatures.
[0036] The present inventors have surprisingly discovered a
lubricant or grease composition which does not include primary,
secondary, tertiary, cyclic aliphatic low molecular weight
(<C30) monoamines or polyamines and/or the corresponding acid
phosphate amine salts which, in preferred embodiments, exhibits
improved performance in at least one of oxidative stability, seal
compatibility, and anti-wear protection, while causing no
significant deficits in other important areas of performance.
SUMMARY OF THE INVENTION
[0037] The invention is directed to a lubricating fluid or grease,
the improvement comprising the absence of primary, secondary,
tertiary, and cyclic hydrocarbyl amines with a carbon number of
less than C30 and the absence of the corresponding acid phosphate
amine salts.
[0038] In embodiments, the additive system used in the lubricating
fluid is characterized by possessing a total base number (TBN) of
less than 22.
[0039] In an embodiment, the invention is further characterized as
comprising an effective amount of an acid phosphate antiwear
additive. In preferred embodiments, the phosphate antiwear additive
will be at least one mono- and/or dialkyl acid phosphate effective
for antiwear protection.
[0040] Preferred mono- and/or dialkyl acid phosphates are
represented by the formula (R.sub.1O)(R.sub.2O)P(O)OH, where
R.sub.1 is hydrocarbyl and R.sub.2 is hydrocarbyl or hydrogen.
R.sub.1 and R.sub.2 may have the same or different hydrocarbyl
groups.
[0041] The present invention is also directed to the use of such
lubricating fluids and greases in gears, drives, axles,
transmissions, and the like, in hydraulic and circulating systems,
and in metal working. The invention is further directed to the use
of apparatus comprising seals and lubricating fluids and/or greases
in contact with said seals, the improvement comprising fluids
and/or grease including the additive package in accordance with
embodiments of the invention.
[0042] It is an object of the invention to provide, in preferred
embodiments, fully formulated lubricating fluids and greases having
improvements in at least one of the properties of antiwear
characteristics, oxidative stability, and seal performance.
[0043] These and other objects, features, and advantages will
become apparent as reference is made to the following detailed
description, preferred embodiments, examples, and appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] In the accompanying drawings, like reference numerals are
used to denote like parts throughout the several views.
[0045] FIG. 1 is a comparison of TBN for additive systems according
to embodiments of the invention versus a commercial additive
package.
[0046] FIG. 2 is a comparison of the carbon varnish rating of
formulations according to embodiments of the present invention
versus comparative formulations.
DETAILED DESCRIPTION
[0047] According to the invention, a lubricating fluid or grease is
provided without the use of primary, secondary, tertiary, or cyclic
hydrocarbyl amine rust inhibitors with a carbon number of C30 or
less, or the corresponding acid phosphate amine salts which, in
certain embodiments, provides improvements in at least one of the
areas of oxidation stability, seal compatibility and anti-wear
performance, while causing no appreciable deficits in other areas
of performance. More particularly, the invention relates to
lubricating compositions useful in automotive gear boxes and
differentials as well as industrial gear boxes.
[0048] In preferred embodiments, fully formulated lubricating
oils/greases and functional fluid compositions comprise an acid
phosphate antiwear additive, preferably one or more hydrocarbyl or
dihydrocarbyl acid phosphates, and there are essentially no acid
phosphate hydrocarbyl amine salts, where the hydrocarbyl mono or
polyamine is C30 or less, present in said fully formulated
compositions. Until now, it has been believed that the stability of
a phosphate-containing antiwear additive was dependent on the
presence of this hydrocarbyl amine such that the phosphorus species
is present, wholly or at least in part, as a salt of the amine with
the acid phosphate. It is the surprising discovery of the present
inventors that such is not the case. Moreover, improvements in
certain important properties are evident in certain compositions
according to embodiments of the present invention.
[0049] It should be understood that in the expression "effective
amount of an acid phosphate-containing antiwear additive", both the
"effective amount" and the identity of the acid
phosphate-containing compound effective as an antiwear additive can
readily be determined by one of ordinary skill in the art in
possession of the present disclosure without more than routine
experimentation.
[0050] According to the invention, the term "phosphate" does not
include any of the sulfur-containing compounds, e.g., thiophosphate
compounds. In an embodiment, the acid phosphate may be present as
the mono and/or dihydrocarbyl esters of the acid phosphate. The
resulting gear lubricant is essentially free of hydrocarbyl
primary, secondary, tertiary, and cyclic amine rust inhibitors with
30 carbons or less as an ingredient (when the invention is
expressed as a "recipe" of ingredients) and therefore the final
fully formulated lubricant is essentially free of the corresponding
acid phosphate amine salts.
[0051] In order to avoid misunderstanding, "essentially free of"
allows for minor amounts, such as inevitable impurities which might
lead to the presence of one or more of primary, secondary,
tertiary, or cyclic aliphatic low molecular weight amines with 30
carbons (C30) or less and/or the presence of the corresponding acid
phosphate amine salts but these ingredients and the constituents
that form them are not present in an amount that might effect the
novel and basic characteristics of the lubricating fluid.
[0052] By omitting these amines from the additive concentrate and
ultimately the lubricant, the additive system will have a
significantly reduced total base number (TBN) for the package. The
additive concentrates covered by this invention have a TBN <22,
some cases less than 20, or less than 15, or less than 10, or even
less than 5.
[0053] FIG. 1 is a plot of TBN and TAN (Total Acid Number) of a
commercial additive package versus additive packages according to
embodiments of the present invention. The commercial additive
package was chosen because it has the lowest TBN in the population
of commercial additive packages examined by the inventors. All
other commercial packages tested by the inventors had higher TBN
numbers. It is highly surprising that the additive packages
according to embodiments of the present invention can provide the
benefits set forth herein with low TBN in view of the TBN of prior
art commercial products.
[0054] In addition, by omitting essentially all of the low
molecular weight (.ltoreq.C30) hydrocarbyl amine rust inhibitors
from the gear lubricant, and therefore eliminating the resulting
phosphate amine salts, a number of very important performance
benefits may be achieved in embodiments, which in preferred
embodiments contribute enhanced durability.
[0055] The first of these performance benefits is enhanced antiwear
performance. As discussed in the experimental section below,
testing according to the industry-recognized L-37 rig test (ASTM
D6121) has shown significant improvements particularly in the low
temperature version (conventionally known as the "Canadian
version") of this test.
[0056] Also, in embodiments, the oxidative stability of gear oils
without the hydrocarbyl amine rust inhibitor described earlier is
superior to those with such an amine present. It has been shown
that when the low molecular (.ltoreq.C30) hydrocarbyl amines are
eliminated from a gear lubricant, the oxidation performance is
dramatically improved. This can be demonstrated using the industry
oxidation test called the L-60-1 (ASTM D5704).
[0057] Improved seal performance was also noted from a gear
lubricant formulated in accordance with the invention. The ASTM
D5562 static seal test was run using both fluoroelastomer (Viton)
and polyacrylate seal materials. In both tests, the elongation
percent loss was significantly reduced.
[0058] It has been expected that fluids formulated without low
molecular weight hydrocarbyl amine rust inhibitors would be
deficient in the area of rust inhibition. In embodiments of the
invention, the rust performance of gear lubricants prepared within
the scope of the invention was evaluated using the automotive gear
industry's L-33 test (ASTM D7038). The results surprisingly
demonstrate that fluids formulated in this manner had no steel
corrosion deficiencies.
[0059] It is preferred that the finished gear lubricant according
to embodiments of the present invention also include at least one
of the ingredients from the group consisting of: a
sulfur-containing extreme pressure (EP) agent, a
nitrogen-containing dispersant, and a corrosion inhibitor. Other
preferred additives may include at least one ingredient selected
from the group consisting of: borated dispersants, non-aminic rust
inhibitors, defoamants, pour point depressants, antioxidants,
demulsifiers, friction modifiers, seal swell agents, chromophores,
deodorants, limited slip additives, detergents, and tackifiers.
[0060] In an embodiment, the invention is directed to a lubricant
comprising a major amount of an oil of lubricating viscosity and a
minor amount of at least one substituted phosphoric acid
composition characterized by the formula
(R.sub.1O)(R.sub.2O)P(O)OH, where R.sub.1 is a hydrocarbyl group
and R.sub.2 is either hydrogen or a hydrocarbyl group.
[0061] The term "major amount" means present in an amount greater
than any other ingredient, based on wt. %. The "oil of lubricating
viscosity" will also be described as a "base oil" herein, and may
be a combination of one or more base oils, with the term "major
amount" meaning the sum of the base oils are present in an amount
greater than any other ingredient.
[0062] The lubricant composition preferably will also contain a
sulfur-containing extreme pressure agent.
[0063] The lubricant composition preferably also will contain
nitrogen-containing dispersants and corrosion inhibitors, with the
proviso that said species not include low molecular weight primary,
secondary, tertiary, or cyclic aliphatic mono and/or polyamines
with 30 carbons or less.
[0064] The products according to embodiments of the invention may
be used for a wide variety of automotive and industrial gear
applications. Examples of such applications include use in hypoid
axles and in mechanical steering drives in passenger cars and in
cross-country vehicles. In addition, the products based on
embodiments of the present invention may be used in planetary hub
reduction axles, mechanical steering and transfer gear boxes in
utility vehicles such as trucks. It also can be used in different
types of gear boxes, e.g. synchromesh gear boxes, as well as power
take-off gears, limited slip axles, and Planetary hub reduction
gear boxes.
[0065] The lubricating oil and functional fluid compositions
according to embodiments of the present invention are based on
diverse oils of lubricating viscosity, including natural and
synthetic lubricating oils and mixtures thereof. These lubricating
compositions are particularly effective as gear lubricants for both
industrial and automotive gear applications, but could also be
considered for other lubricant applications, e.g. hydraulic, metal
working, turbine, circulating, and small engine.
[0066] Compositions according to embodiments of the invention may
further comprise one or more base oils. It will be recognized that
in certain instances it may be convenient to have a lubricant
composition which is not completely formulated, i.e., with a minor
amount of additives left to be added by the final end consumer, for
the purposes of the present disclosure a "fully formulated"
lubricant composition means that any additional components to be
added do not affect the novel and basic characteristics of the
lubricant according to the present invention.
[0067] Fluids that can meet the criteria of base oil for lubricant
and functional fluids are varied. They may fall in any of the
well-known American Petroleum Institute (API) categories of Group I
through Group V. The API defines Group I stocks as solvent-refined
mineral oils. Group I stocks contain the most unsaturates and
sulfur and have the lowest viscosity indices. Group I defines the
bottom tier of performance. Group II and III stocks are high
viscosity index and very high viscosity index base stocks,
respectively. The Group III oils contain the lowest level of
unsaturates and sulfur relative to Group I and II oils. With regard
to certain characteristics, both Group II and Group III oils
perform better than Group I, particularly in the area of oxidative
stability and low temperature performance.
[0068] Group IV stocks consist of polyalphaolefins, which can be
produced via the catalytic oligomerization of linear alphaolefins
(LAOs), with particularly preferable LAOs selected from C5-C14
linear alphaolefins, more preferably from 1-hexene to
1-tetradecene, more preferably from 1-octene to 1-dodecene, and
mixtures thereof, although oligomers of lower olefins such as
ethylene and propylene, oligomers of ethylene/butene-1 and
isobutylene/butene-1, oligomers of ethylene with other higher
olefins, such as described in U.S. Pat. No. 4,956,122, and the
patents referred to therein, and the like, may also be used. PAOs
typically offer superior volatility, thermal stability, and pour
point characteristics to those base oils in Group I, II, and
III.
[0069] Group V includes all the other base stocks not included in
Groups I through IV. Group V base stocks include, e.g., esters,
alkylated aromatics, polyinternal olefins (PIOs), polyisobutylenes,
polyalkylene glycols (PAGs), etc.
[0070] One of the benefits of embodiments of the present invention
is that it may be applicable to base oils fitting into any of the
above five categories, API Groups I to V, as well as other
materials.
[0071] In preferred embodiments, the lubricating compositions of
the invention comprise an additive system which includes
ingredients selected from the group consisting of one or more
sulfur-containing extreme pressure agents, one or more acid
phosphates (pentavalent phosphorus), one or more ashless
dispersants, one or more corrosion inhibitors, and optionally
anti-foamants, pour point depressants, friction modifiers,
demulsifiers, tackifiers, VI improvers, deodorants, seal swell
agents, and non-amine rust inhibitors, and mixtures thereof, with
the proviso that it is essentially free of: (a) low molecular
weight (C30 or less) primary, secondary, tertiary, and cyclic
hydrocarbyl amines; and (b) the corresponding acid phosphate amine
salts.
[0072] While each of the aforementioned ingredients are per se
known in the art, preferred embodiments are discussed in more
detail below.
[0073] Extreme Pressure Agents
[0074] Extreme pressure (EP) agents used in the composition
according to embodiments of the invention include sulfur-containing
and boron-containing EP agents. Sulfur-containing EP agents are
preferred.
[0075] Sulfurized olefins may be useful in providing protection
against high pressure, metal-to-metal contacts in industrial and
automotive gear oils. There is no particular restriction on the
sulfur-containing extreme pressure additive that can be used in the
additive package. Sulfur-containing components useful in this
regard included sulfurized olefins, dialkyl polysulfides,
diarylpolysulfides, sulfurized fats and oils, sulfurized fatty acid
esters, trithiones, sulfurized oligomers of C2-C8 monoolefins,
thiophosphoric acid compounds, sulfurized terpenes, thiocarbamate
compounds, thiocarbonate compounds, sulfoxides, and thiol
sulfinates. Mixtures of sulfur-containing EP components may be
used.
[0076] The preferred sulfur-containing EP components are selected
from sulfurized oligomers of C2-C8 monoolefins, olefins sulfides,
and dialkyl and diaryl polysulfides. The more preferred extreme
pressure agents are oligomeric olefin sulfides and dialkyl
polysulfides. In the most preferred embodiment, the sulfurized
olefin is prepared via a high pressure sulfurization procedure.
[0077] For some gear oil applications, it is possible that
boron-containing EP additives may be adequate, provided that
significant amounts of water are not present to cause hydrolysis.
Use of boron-containing EP agents alone or with sulfur-containing
EP agents are both contemplated. However, in preferred embodiments,
the composition does not use an extreme pressure ingredient
containing boron.
[0078] Dispersants
[0079] Dispersants serve inter alia to keep sludge and varnish
particles from coating on the gear surfaces. There are no
particular restrictions on the type used, though it is preferable
that at least one contains nitrogen. Nitrogen-containing
dispersants include alkyl succinimides, alkenyl succinimides,
benzylamine compounds (Mannich bases), polybutenylamines, and the
like. Borated versions of any of these are optional.
[0080] In some preferred embodiments, nitrogen-containing
dispersants are selected from alkyl succinimides and alkenyl
succinimides. The especially preferred ashless dispersant for use
in this invention are the products of reaction of a polyethylene
polyamine, e.g. tetraethylene pentamine, with a
hydrocarbon-substituted anhydride made by the reaction of a
polyolefin, preferably having a molecular weight of about 700-5000
and especially 800-3000 (it is not particularly important whether
this is number average molecular weight or weight average molecular
weight) with an unsaturated polycarboxylic acid or anhydride, e.g.
maleic anhydride.
[0081] Borated dispersants are optional and may be formed by
borating ashless dispersants using suitable boron-containing
compounds: boron acids, boron oxides, boron esters, and amine or
ammonium salts of boron acids.
[0082] Corrosion Inhibitors/Metal Passivators
[0083] Corrosion inhibitors or metal passivators are typically
additives that are heterocyclic in nature and are nitrogen-, and
optionally, sulfur-containing. Triazole and its derivatives have
been found to prevent corrosion in gear oils. Some specific
examples include benzotriazole, tolyltriazole, 2-mercaptotriazole,
dodecyltriazole. Alkyl and aryl derivatives are preferred.
[0084] A specific class of passivators is known as "copper
passivators." These comprise a class of compounds which includes
thiadiazoles, triazoles, and thiazoles. The preferred compounds are
the 1,3,4-thiadiazoles.
[0085] Phosphate Anti-Wear Agents
[0086] In preferred embodiments, an effective amount of at least
one mono- and/or dialkyl acid phosphate for antiwear protection.
Preferred mono- and/or dialkyl acid phosphates antiwear additives
include at least one species represented by the formula
(R.sub.1O)(R.sub.2O)P(O)OH, where R.sub.1 is hydrocarbyl and
R.sub.2 is hydrocarbyl or hydrogen. R.sub.1 and R.sub.2 may have
the same or different hydrocarbyl groups. Suitable hydrocarbyl
groups have 1-40 carbon atoms, preferably 2-20 and more preferably
3-20. The preferred acid phosphates are selected from mono- and
di-2-ethylhexyl acid phosphates and mixtures thereof.
[0087] Acid phosphates would be preformed salts comprising the acid
phosphate and a low molecular weight hydrocarbyl amine or the acid
phosphate salt would be formed in situ in the additive package or
the finished lubricant or grease (or at some other point between
prior to or even during actual use). Such salts are described in,
e.g., U.S. Pat. Nos. 2,063,629, 2,224,695, 2,447,288, 2,616,905,
3,728,260, 3,984,448, and 4,431,552. The hydrocarbyl amine is often
termed a "rust inhibitor" and is usually a low molecular weight (,
less than or equal to C30, i.e., .ltoreq.C30) primary or secondary,
mono or polyamine, but could also be tertiary or cyclic
mono/polyamines. The preferred amines are generally aliphatic in
nature and possess from 4-30 carbon atoms. Some specific examples
include the following: octylamine, decenylamine, dodecenylamine,
oleylamine, and the like. Typically, the most preferred amines are
described as a complex with acid phosphates, where the aliphatic
group of the amine is a tertiary alkyl group and the amine is a
primary amine. Primene 81-R and Primene JMT amines are typically
describes as most preferred.
[0088] The present inventors have surprisingly found that by
eliminating essentially all of the low molecular weight hydrocarbyl
amine "rust inhibitors", and (without wishing to be bound by
theory) the corresponding acid phosphate salt complex, the additive
system will still possess adequate rust performance, even without
the addition of other rust inhibitors and will also have, in at
least some embodiments, at least one improved property selected
from oxidation stability, seal compatibility and antiwear
protection.
[0089] Optional additives that may be included in the additive
concentrate or the lubricating composition include: defoamants,
non-aminic rust inhibitors, seal swell agents, friction modifiers,
antioxidants, deodorants, chromophores, pour point depressants,
tackifiers, demulsifiers, detergents, VI modifiers, and mixtures
thereof. One of ordinary skill in the art, in possession of the
present disclosure, can determine the nature and quantity of
additives to provide in the fully formulated lubricant or grease
without undue experimentation.
[0090] It should be noted that various ingredients may combine with
the other ingredients to form salts, adducts, coordinated species,
and the like. The combination of such species may be formed prior
to addition to the final lubricant fluid (e.g., in an additive
package), they may be formed in situ with a small amount of diluent
(typically the final basestock) or they may be formed in situ after
the ingredients are added to the basestock. Various combinations
are possible. With this in mind, the present disclosure thus should
be read in the nature of a recipe as regards the various additive
described herein.
[0091] Furthermore, although all ingredients added to the final
fully formulated lubricating fluid or greases described herein may
be provided in a single additive package, the term "additive
package" should be taken to mean any one additive package used or
the entire sum of ingredients added to the one or more base oils
used to create the final fully formulated composition.
EXAMPLES
[0092] The following examples are meant to illustrate the present
invention and provide a comparison with lubricant formulation
which, although heretofore considered adequate for commercial
purposes, are not prepared in accordance with the present
invention. While the examples of the invention are described with
particularity, they should not be taken to limit the invention.
Rather, numerous variations or modifications will become apparent
to (and can be readily made by) those of ordinary skill in the art
in light of these examples, particularly when viewed together with
the entire disclosure.
[0093] For automotive applications, the oils were tested in the rig
tests that are incorporated into API and SAE standards GL-5 and
J2360, respectively. The L-37 test was used to assess antiwear
performance; the L-60-1 was used for oxidative and thermal
stability; and the static seal test ASTM D5662 was run for
polyacrylate and fluoroelastomer seal compatibility. The L-42 for
protection against scoring and the L-33 and ASTM D130 for corrosion
protection were also run to demonstrate no deficiencies as a result
of amine elimination. For industrial gear oils, the ASTM D2783 Four
Ball EP test and ASTM D665 for rust were run.
Automotive Example
[0094] To evaluate a gear lubricant according to the present
invention, the axle test ASTM D6121 was employed. This particular
test is more commonly known as the L-37 test and is used in the
industry to evaluate the antiwear performance of an automotive gear
lubricant. This test method measures a lubricant's ability to
protect final drive axles from abrasive wear, adhesive wear,
plastic deformation, and surface fatigue, when subjected to
low-speed high-torque conditions. Lack of protection can lead to
premature gear or bearing failure or both.
[0095] The test apparatus is a new, complete hypoid truck axle
assembly, Dana Model 60 with 5.86 to 1 ratio. The assembly is
mounted on a test stand with the pinion and axle shafts' center
lines horizontal. The gears are first run through a conditioning
phase and then through a test phase. The test phase is 24 h+0.2 h
and is run at 275.degree. F. with a load of 1740 ft-lb on each
wheel and 80 rpms/min. At the end of the test, the differential is
disassembled and the ring gear and pinion are inspected and rated
for each type of distress (e.g. spalling, pitting, ridging, wear,
rippling, etc.). The rating value is reported.
[0096] This same test method is also used for the Canadian version
of the test, known as the Low Temperature (LT) L-37. The LT L-37
axle test is required for 75 W gear oils. This procedure is
identical to the regular temperature L-37, except that the
temperature of the test is run approximately 55.degree. F. lower
during both the conditioning and gear test phase.
[0097] The oxidative and thermal stability were evaluated in ASTM
D5704 or the L-60/L-60-1 test, which is the most common test
procedure for evaluating these features of automotive gear oils.
The test covers the oil-thickening and insolubles/deposit formation
characteristics of the lubricant when subjected to high temperature
oxidizing conditions. For the L-60 test, the candidate lubricant is
heated to 325.degree. F./163.degree. C. for 50 hr in a small gear
box with two lightly loaded spur gears. Air is bubbled through the
oil at a rate of 1 L/hr. The viscosity of the oxidized oil is
measured at the end of the test and compared to the initial value.
The pentane and toluene insolubles are also measured. The L-60-1
test is run in the same manner; however, the carbon-varnish and
sludge are measured along with the insolubles and the viscosity
increase.
[0098] For seal compatibility, ASTM D5662 was run. This is a
laboratory test method which evaluates gear oils for compatibility
with various elastomers: nitrile, polyacrylate, and
fluoroelastomer. This method addresses failures that may be caused
by excessive elastomer hardening, elongation loss, and volume swell
and attempts to determine the likelihood that an oil might cause
premature sealing system failures in the field. Specimens are cut
from the elastomer being evaluated and are immersed in oil for 240
hr. Reference oils are run periodically. The test temperature is
dependent on the type of seal material used: 100.degree. C. for
nitrile and 150.degree. C. for fluoroelastomer and polyacrylate. At
the end of 240 hr, the aged elastomer specimens are tested for
changes in hardness, elongation, tensile strength and volume.
[0099] Lubricating compositions, Oils A1 and A2 were prepared in
accordance with embodiments of the invention whereas Oils X1 and X2
were formulated for comparison. The contents of these fluids are
shown in Table 1 below. The additive systems of all examples use
identical components, differing only in percentages. The additive
percentages of X1 and X2 were manipulated to provide the closest
approach to the percent of S, P, and N additives in A1 and A2,
respectively, which is believed to provide the most valid
comparison. The key difference between A1 and X1, and between A2
and X2, is the omission of the hydrocarbyl primary amine rust
inhibitor in examples A1 and A2. The TBNs for the additive
concentrates were calculated using a potentiometric method ASTM D
2896. Oils A1 and A2 have a TBN=14.8 and Oils X1 and X2 have
TBN=27.9.
TABLE-US-00001 TABLE 1 Embodiment of Comparison Embodiment of
Comparison Test the Invention Example the Invention Example Oil
Code A1 X1 A2 X2 Additives in Finished Fluid, wt % EP Agent,
Mobilad C-175 3.65 4.24 3.65 4.24 Antiwear - Mobilad C-421 - Acid
Phosphate 1.13 1.37 1.13 1.37 Amine Rust Inhibitor - Primary Amine
(<C30) 0 0.59 0 0.59 Dispersant, Borated and non-borated 3.51
2.00 3.51 2.00 Copper Passivator - thiadiazole 0.54 0.25 0.54 0.25
Other additives (inhibitors, antioxidants, 1.19 1.19 1.19 1.19
defoamants) TBN of Additive System ASTM D2896 14.8 27.9 14.8 27.9 S
in Finished Oil 2.07 2.19 1.95 2.190 P in Finished Oil 0.128 0.157
0.125 0.158 N in Finished Oil 0.14 0.14 0.14 0.11 Basestocks, wt %
PAO 2, 6 cSt 20.0 20.4 26.0 26.4 PAO 150 55.0 55.0 44.0 44.0
Isononyl Heptanoate 15.0 15.0 20.0 20.0 Viscometrics of Finished
Fluid KV 100.degree. C., cSt ASTM D445 19.65 18.04 11.8 11.3 VI
ASTM D2270 216 219 226 229 Brookfield at -40.degree. C., cP ASTM
D2983 21,495 17,300 7,318 6,470
[0100] In the actual L-60-1 test, Oils A1 and A2 had much improved
carbon-varnish ratings compared with Oil X1 and Oil X2. The results
are shown in Table 2. Based on this test alone, the ratings results
for Oils X1 and X2 are considered as "failing". FIG. 2 shows
graphically the superior C-V performance of the candidate oils.
Since the cleanliness is related to the C-V rating, it can be
stated that the oils are cleaner. Pentane and toluene insolubles
were non-existent for Oils A1 and A2 but around 0.3-0.4 mass
percent for the oils X1 and X2. The sludge rating for all four oils
was not significantly different.
[0101] An improvement in the seal compatibility was also observed
for Oils A1 and A2 relative to Oil X2 in the seal test ASTM D5662
(testing of X1 was considered superfluous on the basis of the
results for X2). The change in percent elongation was reduced for
both the fluoroelastomer and polyacrylate with Oils A1 and A2 (see
Table 2 for data), which implies that the candidate oils are having
less affect on the elastomer than the comparative Oil X2.
[0102] The oils were evaluated in the ASTM D130 Copper Corrosion
Test as well as in the L-33 Rust Test. The copper strip was rated
1b for all four oils. It is somewhat surprising that formulations
without the aminic rust inhibitor achieves the same result as the
commercially acceptable formulations with the rust inhibitor. In
the L-33 test, all formulations were well above the pass/fail line
of 9.0 as referenced in SAE J2360 (see Table 2 for data).
[0103] The L-42 test is used for determining the anti-scoring
properties of gear lubricants under high speed and shock
conditions. It is described as having the same effect on gears as
the start of a drag race. The test unit consists of Dana rear axle
44-1 with a gear ratio of 45:11. In a similar fashion as the L-37
test, the gears are mounted on a test stand with the pinion and
axle shafts' center lines horizontal. The gears are put through a
series of accelerations and decelerations against dynamometers
under specified conditions of speed and torque for four cycles. The
gear teeth are inspected at the end of the test for the amount of
scoring on the tooth surface. The amount of scoring must be less
than or equal to the pass reference oil. Both oils were tested and
the data are presented in Table 2. Oils A1 and A2 had acceptable
performance, proving the absence of low molecular weight
hydrocarbyl amine does not hurt scoring performance.
[0104] These data reveal that the automotive gear oils formulated
in accordance with embodiments of this invention had excellent
performance, despite missing the rust inhibitor. Performance was
better in areas of oxidation, anti-wear and seal performance and in
areas that one might expect to be problematic, e.g. rust and copper
corrosion, was not affected significantly.
TABLE-US-00002 TABLE 2 Embodiment of Comparison Embodiment of
Comparison Test the Invention Example the Invention Example Oil
Code A1 X1 A2 X2 Copper Corrosion ASTM D130 1b 1b 1b 1b Pinion Ring
Pinion Ring Pinion Ring Pinion Ring L-37 Test, Uncoated Gears ASTM
D6121 Burnish 5 5 5 5 5 5 5 5 Discoloration 6 6 6 6 6 7 6 7
Corrosion 10 10 10 10 10 10 10 10 Deposits 10 9 10 10 10 10 9 9
Wear 6 8 6 7 7 7 6 7 Scoring 10 10 10 10 10 10 10 10 Rippling 8 9 8
9 9 9 8 9 Ridging 8 9 8 9 9 10 8 9 Spitting 9.9 9.9 9.9 9.9 9.9 9.9
9.9 9.9 Overall Merit 8.94 8.92 9.41 8.92 Evaluation Pass Pass Pass
Pass L-37 Test, Uncoated ASTM D6121 Gears, Low Temp. Burnish 5 5 5
5 5 5 3 5 Discoloration 6 6 6 6 6 7 6 6 Corrosion 10 10 10 10 10 10
10 10 Deposits 10 9 10 7 10 9 10 8 Wear 6 8 5 6 6 8 5 6 Scoring 10
10 10 10 10 10 10 10 Rippling 9 10 7 9 9 9 6 9 Ridging 9 10 6 6 9
10 6 6 Spitting 9.9 9.9 8.0 9.9 9.9 9.9 9.0 9.9 Overall Merit 9.56
7.66 9.41 7.66 Evaluation Pass Fail Pass Fail L-60-1 Test (n = 1)
ASTM D5704 % Viscosity Increase 35 22 27 18 Pentane Insolubles 0
0.40 0 0.35 Toluene Insolubles 0 0.41 0 0.37 Carbon/Varnish 9.7 5.8
9.8 5.0 Sludge 9.5 9.62 9.7 9.49 Evaluation Pass Fail Pass Fail
L-42 % Scoring Ring, Coast 4 3 4 5 % Scoring Pinion, Coast 6 5 9 8
% of Pass/Fail Reference 26 24 33 32 Evaluation Pass Pass Pass Pass
Seal Compatibility ASTM D5662 Fluoroelastomer, % -14.7 nd -12.7
-34.9 elongation change Polyacrylate, % 11.0 nd 28.0 70.5
elongation change Nitrile, % elongation -55.8 nd -53.4 -56.6 change
L-33-1 Test ASTM D7038 Merit Rating 9.31 9.91 9.56 9.83 Evaluation
Pass Pass Pass Pass
[0105] Industrial Gear Fluids
[0106] Industrial gear fluids were also formulated in accordance
with embodiments of the present invention and one was tested in an
effort to demonstrate acceptable performance despite the omitted
low molecular weight (less than or equal to C30) hydrocarbyl amine
and the corresponding phosphate amine salt. Oil B was one such
candidate, i.e. no low molecular weight (.ltoreq.C30) hydrocarbyl
amine was part of the additive system. Here again, the additive
package's TBN was unusually low, measured at 4.5. Table 3 below
shows the composition of the additive system and the mineral base
oils that were employed.
TABLE-US-00003 TABLE 3 Embodiment of Comparison Test the Invention
Example Oil Code B Y Additives in Finished Lubricant, wt % EP
Agent, Mobilad C-170 0.56 0.56 Antiwear - Mobilad C-421 - Acid
Phosphate 0.37 0.37 Amine Rust Inhibitor - Primary Amine (<C30)
0 0.12 Dispersant, Borated and non-borated 0.09 0.09 Copper
passivator - thiadiazole 0.20 0.09 Other additives (inhibitors,
defoamants, 0.046 0.046 demulsifiers) TBN of Additive System ASTM
D2896 4.5 27.8 S in Finished Oil (additive contribution only) 0.275
0.275 P in Finished Oil 0.0440 0.044 N in Finished Oil 0.017 0.015
Basestocks, wt % 150'' Solvent Paraffinic Neutral 12.5 12.5 150
Bright Stock 86.0 86.0 Viscometrics KV, 100.degree. C. ASTM D445
23.6 23.7 KV, 40.degree. C. ASTM D445 306.3 309.3 VI ASTM D2270 97
97
[0107] To evaluate the performance of an industrial gear lubricant
prepared in accordance with embodiments of the invention,
laboratory bench tests that are part of AIST 224 (formerly USS
224), AGMA 9005-E02, and other common industry specifications, were
employed. Again, antiwear performance and rust protection were
evaluated. ASTM D2783, a Four Ball EP Load Wear Test, measures the
antiwear capability of the gear lubricant. One steel ball under
load is rotated against three stationary balls immersed in oil. The
load is increased until the weld point in kilograms is determined.
The load wear index, an index of the ability of the lubricant to
minimize wear at applied loads, is also measure. ASTM D4172 uses
the Four Ball Test Machine to assess the wear preventive
characteristics of lubricating fluids. A steel ball is rotated atop
of three clamped balls at a rate of 1800 rpms for 60 minutes under
a force of 20 kg at 75.degree. C. The average wear scar of the
three clamped balls is then determined. ASTM D665 is used to
measure protection from steel corrosion. A mixture of test oil is
mixed with either distilled water (Part A) or synthetic sea water
(Part B) at a temperature of 60.degree. C. with a cylindrical steel
rod completely immersed. After four hours, the test rod is examined
for signs of rusting. Copper corrosion performance was roughly
equivalent for the two oils as determined by ASTM D130. The results
for Oil B and comparison Oil Y are shown in Table 4.
TABLE-US-00004 TABLE 4 Embodiment of Comparison Test the Invention
Example Oil Code B Y Copper Corrosion ASTM D130 1a 1b Four Ball
Wear ASTM D4172 Wear Scar, mm 0.31 0.35 Four Ball Weld ASTM D2783
Load Wear Index, kg 53 63 Weld Point, kg 250 250 Rust Test ASTM
D665 Part A Pass Pass Part B Pass Pass
[0108] From these results, one can see there is no significant
detrimental effect for this industrial gear oil when the
hydrocarbyl amine rust inhibitors are omitted from the package. The
rust test ASTM D665 is readily passed with both distilled and salt
water. Copper corrosion protection is also satisfactory for the
candidate fluid based on ASTM D130 results. The antiwear
performance is roughly equivalent as evidenced by the Four Ball
Wear and EP test results.
[0109] The invention has been described above with reference to
numerous embodiments and specific examples. Many variations will
suggest themselves to those skilled in this art in light of the
above detailed description. All such obvious variations are within
the full intended scope of the appended claims. Nevertheless,
several particularly preferred embodiments may be pointed out.
[0110] Preferred embodiments include a fully formulated lubricating
fluid or grease including an effective amount of an acid
phosphate-containing antiwear additive, characterized as comprising
an additive package and a major amount of at least one base oil,
the improvement comprising the absence of low molecular weight
primary, secondary, tertiary, and cyclic aliphatic amines of 30
carbons or less and the absence of the corresponding acid phosphate
amine salts, with still more preferred embodiments, which may be
combined as would be recognized by one of ordinary skill in the art
in possession of the present disclosure, selected from: (i) wherein
said additive package has a TBN<22 (or TBN<20, or TBN<15,
or TBN<10, or TBN<5; (ii) wherein said acid phosphate is
selected from at least one mono and/or dihydrocarbyl ester of an
acid phosphate characterized by the formula (1):
(R.sub.1O)(R.sub.2O)P(O)OH, where R.sub.1 is a hydrocarbyl group
and R.sub.2 is selected from hydrogen or a hydrocarbyl group,
particularly wherein the hydrocarbyl groups of R.sub.1 and R.sub.2
are independently selected from straight-chained or branched alkyl
groups having from 1 to 20 carbon atoms, or from 2 to 20 carbon
atoms, or from 3 to 20 carbon atoms, any of which may be modified
by the further limitation that at least one of R.sub.1 and R.sub.2
is 2-ethylhexyl; (iii) further characterized as comprising at least
one of the following ingredients: (a) at least one
sulfur-containing extreme pressure agent; (b) at least one
nitrogen-containing dispersant; (c) at least one corrosion
inhibitor; (iv) further comprising at least one ingredient selected
from the group consisting of borated dispersants, non-aminic rust
inhibitors, defoamants, pour point depressants, antioxidants,
demulsifiers, friction modifiers, seal swell agents, chromophores,
deodorants, limited slip additives, detergents, VI modifiers, and
tackifiers; (v) further characterized by a major amount of at least
one base oil selected from API Groups I to V; (vi) further
characterized by at least one of the following criterion: (a) rated
1a or 1b according to the Copper Corrosion test according to ASTM
D130; (b) passing the Four Ball Weld test according to ASTM D2783
with a Weld Point of 250 kg minimum and a Load Wear Index of 45 kg
minimum; (c) passing the Rust Test, Part A and Part B, according to
ASTM D665; (d) having a value of at least 9.0 or greater in the L33
test, run according to ASTM D7038.
[0111] Another preferred embodiment is an apparatus comprising at
least one seal and a lubricating fluid or grease in contact with
said seal, wherein said lubricating fluid or grease is that
characterized in the previous paragraph, particularly an apparatus
wherein the seal comprises at least one material selected from
fluoroelastomers, nitriles, and polyacrylates, and also
particularly wherein the apparatus, which may have the seal as just
described, comprises at least one of the following: a hypoid axle,
a mechanical steering drive or gear box, a planetary hub reduction
axle or gear box, a transfer gear box, a synchromesh gear box, a
power take-off gear, a limited slip axle, an engine or turbine, a
hydraulic system.
[0112] Still other particularly preferred embodiments are: a
process for metal working or in a circulating fluid system, either
comprising the use of a lubricant or grease, the improvement
comprising the use of the lubricating fluid or grease as described
in the paragraph just above the immediately preceding
paragraph.
[0113] Yet still another particularly preferred embodiment is a
fully formulated lubricating fluid or grease suitable for use in
driveline fluids and/or gear boxes for industrial applications
comprising an additive package and a major amount of at least one
base oil and essentially free of low molecular weight primary,
secondary, tertiary, and cyclic aliphatic amines of 30 carbons or
less and their corresponding acid phosphate salts, which may be
modified in numerous ways described herein, particularly in any of
the ways described in paragraph [00112], but in the important
embodiment which may be characterized as containing an acid
phosphate selected from at least one mono and/or dihydrocarbyl
ester of an acid phosphate characterized by the formula (1):
(R.sub.1O)(R.sub.2O)P(O)OH, where R.sub.1 is a hydrocarbyl group
and R.sub.2 is selected from hydrogen or a hydrocarbyl group,
especially wherein at least one of R.sub.1 and R.sub.2 is
2-ethylhexyl.
[0114] Moreover, a particularly preferred embodiment also is a
method for lubricating an apparatus, the method comprising applying
a lubricant to the apparatus wherein said lubricant comprises a
base oil, an effective amount of an acid phosphate-containing
antiwear additive, said lubricant further characterized as
essentially free of primary, secondary, tertiary and cyclic
hydrocarbyl amines with a carbon number of C30 or less and the
corresponding salts of said acid phosphate, which may of course be
modified by any one or more of the limitations set forth in
paragraph [00112].
[0115] Unless stated otherwise herein, the meanings of terms used
herein shall take their ordinary meaning in the art; reference
shall be taken, in particular, to Synthetic Lubricants and
High-Performance Functional Fluids, Second Edition, Edited by
Leslie R. Rudnick and Ronald L. Shubkin, Marcel Dekker (1999). This
reference, as well as all patents and patent applications, test
procedures (such as ASTM methods and the like), and other documents
cited herein are fully incorporated by reference to the extent such
disclosure is not inconsistent with this invention and for all
jurisdictions in which such incorporation is permitted. Note that
Trade Names used herein are indicated by a .TM. symbol or .RTM.
symbol, indicating that the names may be protected by certain
trademark rights, e.g., they may be registered trademarks in
various jurisdictions. Note also that when numerical lower limits
and numerical upper limits are listed herein, ranges from any lower
limit to any upper limit are contemplated.
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