U.S. patent application number 09/780998 was filed with the patent office on 2002-10-17 for automatic transmission fluids with improved anti-wear properties.
Invention is credited to Srinivasan, Sanjay.
Application Number | 20020151443 09/780998 |
Document ID | / |
Family ID | 25121340 |
Filed Date | 2002-10-17 |
United States Patent
Application |
20020151443 |
Kind Code |
A1 |
Srinivasan, Sanjay |
October 17, 2002 |
Automatic transmission fluids with improved anti-wear
properties
Abstract
Automatic transmission fluids are described which contain at
least 0.05 weight percent of a dialkyl thiadiazole and sulfurized
fat, sulfurized fatty acid, sulfurized fatty acid ester, up to
about 0.15 weight % of a metal-containing detergent, and/or a
mixture thereof. The transmission fluids according to the present
invention exhibit improved anti-wear and extreme pressure
performance.
Inventors: |
Srinivasan, Sanjay;
(Richmond, VA) |
Correspondence
Address: |
James T. Moore
Ethyl Corporation
330 South Fourth Street
Richmond
VA
23219
US
|
Family ID: |
25121340 |
Appl. No.: |
09/780998 |
Filed: |
February 9, 2001 |
Current U.S.
Class: |
508/273 ;
508/331; 508/344; 508/345; 508/469; 508/563 |
Current CPC
Class: |
C10M 161/00 20130101;
C10M 163/00 20130101; C10M 141/08 20130101; C10M 167/00
20130101 |
Class at
Publication: |
508/273 ;
508/331; 508/344; 508/345; 508/469; 508/563 |
International
Class: |
C10M 135/36; C10M
135/06 |
Claims
We claim:
1. An automatic transmission fluid, comprising: (1) a major amount
of a base oil and (2) a minor amount of an additive comprising (A)
at least 0.05 wt %, based on the fluid, of an ashless dialkyl
thiadiazole, (B) a sulfurized fat, sulfurized fatty acid,
sulfurized fatty acid ester or a mixture thereof, and (C) up to
about 0.15 wt %, based on the fluid, of a metal-containing
detergent.
2. An automatic transmission fluid as claimed in claim 1, wherein
component (A) is a compound of the formula: 2wherein R.sup.1 is a
hydrocarbyl substituent having from 6 to 18 carbon atoms; and
R.sup.2 is a hydrocarbyl substituent having from 6 to 18 carbon
atoms and may be the same as or different from R.sup.1.
3. An automatic transmission fluid as claimed in claim 2, wherein
R.sup.1 and R.sup.2 are about 9-12 carbon atoms.
4. An automatic transmission fluid as claimed in claim 3, wherein
R.sup.1 and R.sup.2 are the same, and are each 9 carbon atoms.
5. An automatic transmission fluid as claimed in claim 1, wherein
component (B) comprises at least one sulfurized fatty acid
ester.
6. An automatic transmission fluid as claimed in claim 1, wherein
component (C) comprises at least one calcium-containing
detergent.
7. An automatic transmission fluid as claimed in claim 1, wherein
component (A) is present in an amount of from 0.05 to about 0.75
weight percent, based on the transmission fluid.
8. An automatic transmission fluid as claimed in claim 7, wherein
component (A) is present in an amount of from 0.075 to about 0.25
weight percent, based on the transmission fluid.
9. An automatic transmission fluid as claimed in claim 7, wherein
component (A) is present in an amount of about 0.10 weight percent,
based on the transmission fluid.
10. An automatic transmission fluid as claimed in claim 1, wherein
component (B) is present in an amount of from about 0.10 to about
1.00 weight %, based on the transmission fluid.
11. An automatic transmission fluid as claimed in claim 1, wherein
component (B) is present in an amount of from about 0.25 to about
0.75 weight %, based on the transmission fluid.
12. An automatic transmission fluid as claimed in claim 1, wherein
component (B) is present in an amount of about 0.50 weight %, based
on the transmission fluid.
13. An automatic transmission fluid as claimed in claim 1, further
at least one inhibitor selected from the group consisting of foam
inhibitors, corrosion inhibitors, rust inhibitors, and oxidation
inhibitors.
14. An automatic transmission fluid as claimed in claim 1, further
comprising at least one viscosity index improver, dispersant, or
friction modifier.
15. An automatic transmission fluid as claimed in claim 14, wherein
there is a mixture of viscosity index improvers present.
16. An automatic transmission fluid as claimed in claim 14, wherein
there is at least one dispersant present, and the at least one
dispersant has a total nitrogen to phosphorus mass ratio of between
about 3:1 and about 10:1.
17. An automatic transmission fluid composition comprising: (1) a
major amount of a base oil and (2) a minor amount of an additive
composition comprising: (A) at least 0.05 wt %, based on the fluid,
of a dialkyl thiadiazole, (B) a sulfurized fatty acid ester, (C) up
to about 0.15% of a metal containing detergent, (D) a dispersant
having a total nitrogen to phosphorus mass ratio of between about
3:1 and about 10:1, (E) a diphenylamine antioxidant, and (K) a
mixed viscosity index improver system containing (i) a
nondispersant polymethacrylate, and (ii) a dispersant
polymethacrylate.
18. The automatic transmission fluid of claim 16 further comprising
at least one additive selected from the group consisting of seal
swell agents, foam inhibitors, lubricity agents, and dyes.
19. A method of improving automatic transmission antiwear and
extreme pressure performance, said method comprising adding to, and
operating in, said automatic transmission an automatic transmission
fluid as set forth in claim 17.
20. An automatic transmission fluid composition, which exhibits
good anti wear and extreme pressure performance and stability,
obtained by combining (1) a major amount of a base oil and (2) a
minor amount of an additive composition comprising: (A) at least
0.10 weight % dialkyl thiadiazole, (B) at least 0.10 weight % of at
least one sulfurized fatty acid ester, and (C) up to about 0.15
weight % of a metal-containing detergent.
21. The automatic transmission fluid of claim 19 further comprising
at least one additive selected from the group consisting of seal
swell agents, foam inhibitors, lubricity agents, and dyes.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] There are no related applications.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] This research was not sponsored by any entity of the Federal
Government.
BACKGROUND OF THE INVENTION
[0003] 1. Field of the Invention
[0004] This invention relates to oil-based automatic transmission
fluid compositions having enhanced performance capabilities, more
specifically including improved anti-wear and extreme pressure
performance.
[0005] 2. Description of the Prior Art
[0006] U.S. Pat. No. 5,578,236, to Ethyl Corporation discloses a
power transmission fluid with enhanced performance characteristics.
The power transmission fluid composition disclosed therein has,
inter alia, an oil-soluble boron content of about 0.001 to about
0.1% an oil soluble phosphorus content of about 0.005 to about
0.2%, and an oil soluble metal additive content of from 0 to about
100 ppm.
[0007] The composition of the '236 patent comprises at least about
50 weight % hydrotreated mineral oils in the range of about 55N to
about 125N, about 5 to 40 wt % of hydrogenated poly alpha olefin
oligomer having a viscosity of about 2 to about 6 cSt at
100.degree. C., about 5 to about 20 wt % of an acrylic viscosity
index improver, a seal swell agent, an ashless dispersant, an oil
soluble friction modifier, and an inhibitor selected from foam,
copper corrosion (including thiadiazoles), rust, and oxidation
inhibitors. The finished composition has a Brookfield viscosity of
13,000 cP or less at -40.degree. C., an ASTM D-4683 viscosity of at
least 2.6 mPa.s at 150.degree. C., and a viscosity of at least 6.8
cSt at 100.degree. C. after 40 cycles in the FISST of ASTM D-5275.
However, the compositions disclosed are preferably devoid of
sulfurized components.
[0008] U.S. Pat. No. 5,441,656, also to Ethyl Corporation,
discloses an automatic transmission fluid for overcoming shudder
problems in continuous slip torque converter clutches in automatic
transmissions. The automatic transmission fluid ("ATF") of the '656
patent includes, among other restrictions, a friction modifier
content which contains an N-aliphatic hydrocarbyl substituted
diethanolamine in which the N-aliphatic hydrocarbyl substituent is
free of acetylenic unsaturation and having in the range of about 14
to about 40 carbon atoms, and an N-aliphatic hydrocarbyl
substituted triemethylene diamine in which the N-aliphatic
hydrocarby substituent is at least one straight chain aliphatic
hydrocarbyl group having in the range of about 14 to about 20
carbon atoms. Conventional copper corrosion inhibitors (including
thiadiazoles) and other optional (e.g. lubricity, dye, pour point
depressant, etc.) components may be present.
[0009] U.S. Patent Nos. 5,344,579; 5,372,735; and 5,578,236
disclose automatic transmission fluid compositions which exhibit
good anti-shudder properties.
[0010] Other U.S. Patents which disclose various automatic
transmission fluids include U.S. Pat. Nos. 4,795,583; 4,855,074;
4,857,214; 5,089,156; 5,126,064; 5,164,103; 5,171,466; 5,198,133;
5,256,324; 5,360,562; 5,387,346; 5,387,352; 5,389,273; 5,439,606;
5,505,868; 5,652,201; 5,703,023; 5,817,605; 5,851,962; 5,891,786;
and 5,972,851. Each of the above is incorporated by reference.
[0011] These references, however, fail to teach or suggest the
combination of components of the present invention, including the
combination of at least 0.05% of a ashless dialkyl thiadiazole
corrosion inhibitor with with sulfurized fats, sulfurized fatty
acids, sulfurized fatty acid esters and/or mixtures thereof.
[0012] Commercially, it is known to add various additive packages
to automatic transmission fluid, including, among other things,
extreme pressure agents, antiwear agents, antioxidant systems,
corrosion inhibitor systems, metal deactivators, anti-rust agents,
friction modifiers, dispersants, detergents, anti-foam agents, and
viscosity index improvers. However, not all additives interact
predictably or well with one another.
BRIEF SUMMARY OF THE INVENTION
[0013] The present invention relates to the improvement of
anti-wear and extreme pressure performance and stability of an
automatic transmission fluid by the inclusion of sulfurized fats,
sulfurized fatty acids, sulfurized fatty acid esters and/or
mixtures thereof, and an ashless dialkyl thiadiazole. Other
optional components, e.g. friction modifiers, antioxidants,
dispersants, and viscosity index improvers, allow the fully
formulated transmission fluid composition to provide improved
antiwear and extreme pressure performance when incorporated into an
automatic transmission.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Vehicles meeting the stringent demands of consumers today
require durability and performance in all of the vehicular systems.
One of the most important systems is the power transmission system
("transmission") which transmits the power generated by the
automobile engine to the wheels. It being one of the most complex
systems in the vehicle, it is also one of the most costly to
diagnose, repair, or replace. The transmission usually includes,
inter alia, a clutch with plates, a torque converter, and a
plurality of gears to alter the power delivered to the wheels by
changing the gear ratio.
[0015] Discriminating consumers primarily desire high performance,
low maintenance (high mileage between servicing), and extended life
expectancy. However, with the advent of new transmission
technologies, old standards of performance which were previously
met with approval are now becoming unacceptable.
[0016] For example, there is worldwide activity by the automobile
manufacturers to develop automatic transmissions incorporating
various electronically controlled converter clutch (ECCC) designs.
These developments are being driven by the anticipated increase in
Corporate Average Fuel Economy (CAFE) requirements in the U.S.A.
The ECCC design allows increases in fuel economy to be gained.
[0017] The advent of ECCC transmissions as well as vehicles
equipped with a continuously variable transmission (CVT) and
advances in aerodynamic body design result in passenger cars with
smaller transmissions which tend to operate with higher energy
densities and higher operating temperatures. Such changes have
challenged lubricant suppliers to formulate automatic transmission
fluids with new and unique performance characteristics including
higher torque and friction durability.
[0018] As a result, many original equipment manufacturers (OEMs)
are looking for automatic transmission fluids with frictional
characteristics capable of meeting the requirements of ECCC, CVT,
and other designs while retaining sufficient performance in the
anti-wear arena.
[0019] A need exists for an effective way of overcoming the wear
problem associated with automatic transmissions, especially to meet
the needs of OEM automobile designers and suppliers, for extended
transmission fluid life and durability.
[0020] This invention overcomes the durability and anti-wear
(extreme pressure) problem by providing an automatic transmission
fluid that exhibits good anti-wear performance during its
lifetime.
[0021] In accordance with this invention there is provided an ATF
which surprisingly gives improved wear performance at lower treat
rates. In one of its embodiments, it contains an effective amount
of at least one sulfurized fat, e.g. a sulfurized fatty acid ester,
an ashless dialkyl thiadiazole, and less than 0.10 wt % of a
metal-containing detergent.
[0022] Suitable sulfurized fats include the SUL-PERM.TM. brand of
products. SUL PERM 60-93, a sulfurized fatty ester-polyalkanol
amide type product available from Keil Chemical Division of Ferro
Corporation; SUL-PERM 10E, a product indicated by the manufacturer
thereof, Keil Chemical Division of Ferro Corporation, to contain
9.5% sulfur and to have the following properties: a viscosity at
100.degree. F. of 2000 SUS, a viscosity at 210.degree. F. of 210
SUS, and a specific gravity at 77.degree. F. of 0.9844; EP Oil
GE-10, a product supplied by Hornett Brothers and indicated to have
a sulfur content of 8.5 to 9.5 wt %, a flash point of 150.degree.
C., a viscosity at 100.degree. C. of 30-40 cSt, a density of 0.97
g/mL at 15.degree. C. and an acidity in the range of 5 to 9.5 mg
KOH per gram. Also suitable are products from Elco, such as Elco
46368.
[0023] The corrosion inhibitors according to the present invention
include ashless dialkyl thiadiazoles. Exemplary suitable compounds
include bis-tert-dodecylthiothiadiazole;
2,5-bis(hydrocarbylthio)-1,3,4-thiadiazo- le; and
2,5-bis-(hydrocarbyldithio)-1,3,4-thiadiazole. One commercially
available dialkyl thiadiazole is HiTEC.RTM. 4313, a product of
Ethyl Corporation, Richmond, Virginia. The thiadiazole is
preferably a dialkyl, in which each alkyl is independently a
hydrocarbyl group having from about 9 to about 18 carbon atoms.
[0024] The metal-containing detergents are preferably those
containing a metal from Group 2A of the periodic table, e.g. Be,
Mg, Ca, Sr, Ba or Ra, more preferably a Mg or Ca containing
detergent such as a calcium phenate, calcium sulfonate, magnesium
phenate, or magnesium sulfonate. Especially preferred is a low base
calcium hydroxide salt of a sulfurized alkylphenate such as OLOA
216 C, manufactured by the Oronite Division of Chevron.
[0025] In one embodiment, the fluids of the present invention are
used in formulating automatic transmission fluids which exhibit an
11 stage pass in the FZG test at 150.degree. C., as set forth in
ASTM D 5182-97, which is incorporated herein by reference.
[0026] In another embodiment of the present invention, a method of
improving wear performance in automatic transmissions and a method
of providing good stability is set forth.
[0027] Said methods comprise adding to, and operating in, an
automatic transmission an automatic transmission fluid comprising
(1) a major amount of a base oil and (2) a minor amount of an
additive composition which comprises, as essential components at
least Component (A), Component (B), and Component (C) as described
below.
[0028] Although the Components above and in the below list are
described occasionally with reference to a function, that function
may be one of other functions served by the same component and
should not be construed as a mandatory limiting function.
[0029] Component (A) Ashless Dialkyl Thiadiazole
[0030] Component (A) is an ashless dialkyl thiadiazole. One example
of a commercially available ashless dialkyl thiadiazole is
HiTEC.RTM. 4313 corrosion inhibitor, available from Ethyl
Corporation.
[0031] Dialkyl thiadiazoles suitable for the practice of the
instant invention are of the general formula (I): 1
[0032] wherein R.sup.1 is a hydrocarbyl substituent having from 6
to 18 carbon atoms; R.sup.2 is a hydrocarbyl substituent having
from 6 to 18 carbon atoms; and may be the same as or different from
R.sup.1. Preferably, R.sup.1 and R.sup.2 are about 9-12 carbon
atoms, and most preferably R.sup.1 and R.sup.2 are each 9 carbon
atoms.
[0033] Mixtures of dialkyl thiadiazoles of formula (I) with
monoalkyl thiadiazoles may also be used within the scope of the
present invention. Such mono alkyl thiadiazoles occur when either
substituent R.sup.1 or R.sup.2 is H. However, at least 0.05 weight
percent of the fully formulated fluid composition should comprise
the dialkyl thiadiazole, more preferably at least about 0.10 weight
%. A presently preferred range is from about 0.05 weight % to about
1.00 weight %, more preferably about 0.10 to about 0.75 weight
%.
[0034] Component (B)--Sulfurized Fat
[0035] Component (B) comprises a sulfur source selected from
sulfurized fats, e.g., sulfurized fatty acid esters. These
components may also have functions as lubricity agents and as
extreme pressure (EP) agents as well.
[0036] Various products are available as high sulfur donors, such
as BASE 101 Sulfurized Lard oil; BASE 107 Sulfurized Lard oil; BASE
10L Sulfurized fatty compound; BASE 12SE Sulfurized methyl ester;
BASE 14L Sulfurized fatty compound; BASE 401 Sulfurized
hydrocarbon; BASE 44 Sulfurized Oleic Acid; BASE A92 Sulfurized
fatty compound; SUL-PERM.RTM. 110 Sulfurized sperm oil replacement;
SUL-PERM.RTM. 18 Sulfurized sperm oil replacement; and
SUL-PERM.RTM. 307 Sulfurized sperm oil replacement. Especially
preferred is SUL-PERM.RTM. 10-E, a sulfurized fatty acid ester
containing 10% sulfur. Each of the above products are available
from Keil Chemical Division of Ferro Corporation.
[0037] In a presently preferred embodiment, the sulfur-containing
component is present in the final fluid in an amount of from 0.10
weight % to about 1.00 weight %, more preferably from about 0.25
weight % to about 0.75 weight %.
[0038] Component (C)--Metal Containing Detergent
[0039] Small amounts of certain metal-containing detergents, such
as calcium sulfurized phenates, and calcium sulfonates are used in
the practice of the invention. However, if an oil-soluble phenate
or sulfonate is used it should be proportioned such that the
finished fluid contains no more than about 250 ppm of metal,
preferably no more than about 100 ppm of metal, and most preferably
no more than about 50 ppm of metal. These sulfurized phenates are
preferably neutral salts containing a stoichiometric amount of
calcium, and in any event should have a total base number (TBN) of
not more than about 200 mg KOH/ gram.
[0040] An especially preferred detergent is a low-base calcium
phenate such as OLOA 216 C, available from the Oronite Division of
Chevron. OLOA 216 C is said to be a calcium hydrodroxide salt of a
sulfurized alkylphenate having a nominal TBN of 150.
[0041] In the final fluid, the detergent may be present in an
amount of from 0.01-0.10% by weight, more preferably from about
0.03% to about 0.07% by weight, most preferably about 0.05% by
weight.
[0042] In addition to the above mandatory components, the present
invention may also optionally contain the following additional
components:
[0043] Component (D)--Dispersant
[0044] Component (D) comprises at least one oil-soluble phosphorus
or boron-containing ashless dispersant. The phosphorus or
boron-containing ashless dispersants can be formed by
phosphorylating or boronating an ashless dispersant having basic
nitrogen and/or at least one hydroxyl group in the molecule, such
as a succinimide dispersant, succinic ester dispersant, succinic
ester-amide dispersant, Mannich base dispersant, hydrocarbyl
polyamine dispersant, or polymeric polyamine dispersant.
[0045] The polyamine succinimides in which the succinic group
contains a hydrocarbyl substituent containing at least 30 carbon
atoms are described for example in U.S. Pat. Nos. 3,172,892;
3,202,678; 3,216,936; 3,219,666; 3,254,025; 3,272,746; and
4,234,435. The alkenyl succinimides may be formed by conventional
methods such as by heating an alkenyl succinic anhydride, acid,
acid-ester, acid halide, or lower alkyl ester with a polyamine
containing at least one primary amino group. The alkenyl succinic
anhydride may be made readily by heating a mixture of olefin and
maleic anhydride to, for example, about 180-220.degree. C. The
olefin is preferably a polymer or copolymer of a lower monoolefin
such as ethylene, propylene, 1-butene, isobutene and the like and
mixtures thereof. The more preferred source of alkenyl group is
from polyisobutene having a gel permeation chromotography (GPC)
number average molecular weight of up to 10,000 or higher,
preferably in the range of about 500 to about 2,500, and most
preferably in the range of about 800 to about 1,200.
[0046] As used herein the term "succinimide" is meant to encompass
the completed reaction product from reaction between one or more
polyamine reactants and a hydrocarbon-substituted succinic acid or
anhydride (or like succinic acylating agent), and is intended to
encompass compounds wherein the product may have amide, amidine,
and/or salt linkages in addition to the imide linkage of the type
that results from the reaction of a primary amino group and an
anhydride moiety.
[0047] Alkenyl succinic acid esters and diesters of polyhydric
alcohols containing 2-20 carbon atoms and 2-6 hydroxyl groups can
be used in forming the phosphorus-containing ashless dispersants.
Representative examples are described in U.S. Pat. Nos. 3,331,776;
3,381,022; and 3,522,179. The alkenyl succinic portion of these
esters corresponds to the alkenyl succinic portion of the
succinimides described above.
[0048] Suitable alkenyl succinic ester-amides for forming the
phosphorylated ashless dispersant are described for example in U.S.
Pat. Nos. 3,184,474; 3,576,743; 3,632,511; 3,804,763; 3,836,471;
3,862,981; 3,936,480; 3,948,800; 3,950,341; 3,957,854; 3,957,855;
3,991,098; 4,071,548; and 4,173,540.
[0049] Hydrocarbyl polyamine dispersants that can be phosphorylated
are generally produced by reacting an aliphatic or alicyclic halide
(or mixture thereof) containing an average of at least about 40
carbon atoms with one or more amines, preferably polyalkylene
polyamines. Examples of such hydrocarbyl polyamine dispersants are
described in U.S. Pat. Nos. 3,275,554; 3,394,576; 3,438,757;
3,454,555; 3,565,804; 3,671,511; and 3,821,302.
[0050] In general, the hydrocarbyl-substituted polyamines are high
molecular weight hydrocarbyl-N-substituted polyamines containing
basic nitrogen in the molecule. The hydrocarbyl group typically has
a number average molecular weight in the range of about 750-10,000
as determined by GPC, more usually in the range of about
1,000-5,000, and is derived from a suitable polyolefin. Preferred
hydrocarbyl-substituted amines or polyamines are prepared from
polyisobutenyl chlorides and polyamines having from 2 to about 12
amine nitrogen atoms and from 2 to about 40 carbon atoms.
[0051] Mannich polyamine dispersants which can be utilized in
forming the phosphorylated ashless dispersant is a reaction product
of an alkyl phenol, typically having a long chain alkyl substituent
on the ring, with one or more aliphatic aldehydes containing from 1
to about 7 carbon atoms (especially formaldehyde and derivatives
thereof), and polyamines (especially polyalkylene polyamines).
Examples of Mannich condensation products, and methods for their
production are described in U.S. Pat. Nos. 2,459,112; 2,962,442;
2,984,550; 3,036,003; 3,166,516; 3,236,770; 3,368,972; 3,413,347;
3,442,808; 3,448,047; 3,454,497; 3,459,661; 3,493,520; 3,539,633;
3,558,743; 3,586,629; 3,591,598; 3,600,372; 3,634,515; 3,649,229;
3,697,574; 3,703,536; 3,704,308; 3,725,277; 3,725,480; 3,726,882;
3,736,357; 3,751,365; 3,756,953; 3,793,202; 3,798,165; 3,798,247;
3,803,039; 3,872,019; 3,904,595; 3,957,746; 3,980,569; 3,985,802;
4,006,089; 4,011,380; 4,025,451; 4,058,468; 4,083,699; 4,090,854;
4,354,950; and 4,485,023.
[0052] The preferred hydrocarbon sources for preparation of the
Mannich polyamine dispersants are those derived from substantially
saturated petroleum fractions and olefin polymers, preferably
polymers of mono-olefins having from 2 to about 6 carbon atoms. The
hydrocarbon source generally contains at least about 40 and
preferably at least about 50 carbon atoms to provide substantial
oil solubility to the dispersant. The olefin polymers having a GPC
number average molecular weight between about 600 and 5,000 are
preferred for reasons of easy reactivity and low cost. However,
polymers of higher molecular weight can also be used. Especially
suitable hydrocarbon sources are isobutylene polymers.
[0053] The preferred Mannich base dispersants for this use are
Mannich base ashless dispersants formed by condensing about one
molar proportion of long chain hydrocarbon-substituted phenol with
from about 1 to 2.5 moles of formaldehyde and from about 0.5 to 2
moles of polyalkylene polyamine.
[0054] Polymeric polyamine dispersants suitable for preparing
phosphorylated ashless dispersants are polymers containing basic
amine groups and oil solubilizing groups (for example, pendant
alkyl groups having at least about 8 carbon atoms). Such materials
are illustrated by interpolymers formed from various monomers such
as decyl methacrylate, vinyl decyl ether or relatively high
molecular weight olefins, with aminoalkyl acrylates and aminoalkyl
acrylamides. Examples of polymeric polyamine dispersants are set
forth in U.S. Pat. Nos. 3,329,658; 3,449,250; 3,493,520; 3,519,565;
3,666,730; 3,687,849; and 3,702,300.
[0055] The various types of ashless dispersants described above can
be phosphorylated by procedures described in U.S. Pat. Nos.
3,184,411; 3,342,735; 3,403,102; 3,502,607; 3,511,780; 3,513,093;
3,513,093; 4,615,826; 4,648,980; 4,857,214 and 5,198,133.
[0056] In another preferred embodiment, the dispersants or the
phosphorus-containing dispersants of the present invention are also
boronated.
[0057] Methods that can be used for boronating (borating) the
various types of ashless dispersants described above are described
in U.S. Pat. Nos. 3,087,936; 3,254,025; 3,281,428; 3,282,955;
2,284,409; 2,284,410; 3,338,832; 3,344,069; 3,533,945; 3,658,836;
3,703,536; 3,718,663; 4,455,243; and 4,652,387.
[0058] Preferred procedures for phosphorylating and boronating
ashless dispersants such as those referred to above are set forth
in U.S. Pat. Nos. 4,857,214 and 5,198,133.
[0059] The amount of phosphorylated ashless dispersant on an
"active ingredient basis" (i.e., excluding the weight of
impurities, diluents and solvents typically associated therewith)
is generally within the range of about 0.5 to about 7.5 weight
percent (wt %), typically within the range of about 0.5 to 5.0 wt
%, preferably within the range of about 0.5 to about 4.0 wt %, and
most preferably within the range of about 1.0 to about 3.0 wt
%.
[0060] In a preferred embodiment of the present invention, an
ashless dispersant with an N/P ratio as set forth in U.S. Pat. No.
5,972,851, which is incorporated herein by reference. In this
preferred embodiment, an optional component of the present
invention is a dispersant having a nitrogen to phosphorus mass
ratio between about 3:1 and about 10:1. The dispersant of the
preferred embodiment can be prepared in at least two ways. In one
method, an ashless dispersant is phosphorylated to such a degree
that the nitrogen to phosphorus mass ratio between about 3:1 and
about 10:1. In another embodiment, a phosphorylated dispersant and
a non-phosphorylated dispersant are blended together such that the
total nitrogen to phosphorus mass ratio of the dispersant is
between about 3:1 and about 10:1.
[0061] Overall, the dispersant is preferably present in the final
fluid in an amount of about 1.00% to about 15.00% by weight, more
preferably from about 1.00 weight % to about 8.00 weight %.
[0062] Component (E)--Antioxidants
[0063] The compositions of the present invention may include one or
more antioxidants, for example, one or more phenolic antioxidants,
hindered phenolic antioxidants, additional sulfurized olefins,
aromatic amine antioxidants, secondary aromatic amine antioxidants,
sulfurized phenolic antioxidants, oil-soluble copper compounds,
phosphorus-containing antioxidants (e.g. organic phosphites), and
mixtures thereof.
[0064] Suitable exemplary compounds include include
2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated
phenols, 2,6-di-tert-butyl-4-methylphenol,
4,4'-methylenebis(2,6-di-tert-butylphen- ol),
2,2'-methylenebis(4-methyl-6-tert-butylphenol), mixed
methylene-bridged polyalkyl phenols,
4,4'-thiobis(2-methyl-6-tert-butylph- enol),
N,N'-di-sec-butyl-p-phenylenediamine, 4-isopropylaminodiphenyl
amine, phenyl-.alpha.-naphthyl amine, and phenyl-.beta.-naphthyl
amine.
[0065] Especially preferred antioxidants include diphenyl amine
derived antioxidants; such as Naugalube.RTM. 438-L.
[0066] In the class of amine antioxidants, oil-soluble aromatic
secondary amines; aromatic secondary monoamines; and others are
suitable. Suitable aromatic secondary monoamines include
diphenylamine, alkyl diphenylamines containing 1 to 2 alkyl
substituents each having up to about 16 carbon atoms,
phenyl-.alpha.-naphthylamine, phenyl-.gamma.-naphthylamine, alkyl-
or aralkylsubstituted phenyl-.alpha.-naphthylamine containing one
or two alkyl or aralkyl groups each having up to about 16 carbon
atoms, alkyl- or aralkyl-substituted phenyl-.beta.-naphthylamine
containing one or two alkyl or aralkyl groups each having up to
about 16 carbon atoms, alkylated p-phenylene diamines available
from Goodyear under the tradename "Wingstay 100" and from Uniroyal,
and similar compounds.
[0067] The preferred type of aromatic amine antioxidant is that
embodied in the commercial product Naugalube 483L is an alkylated
diphenylamine of the general formula:
R.sub.1--C6H4-NH--C6H4-R.sub.2
[0068] wherein R.sub.1 is an alkyl group (preferably a branched
alkyl group) having 8 to 12 carbon atoms, (more preferably 8 or 9
carbon atoms) and R.sub.2 is a hydrogen atom or an alkyl group
(preferably a branched alkyl group) having 8 to 12 carbon atoms,
(more preferably 8 or 9 carbon atoms). Most preferably, R.sub.1 and
R.sub.2 are the same. Particularly preferred is a nonylated
diphenyl amine containing 4,4'-dinonylated diphenyl amine; a
bis(4-nonylphenyl)(amine) wherein the nonyl groups are
branched.
[0069] In the class of phenolic antioxidants, suitable compounds
include orthoalkylated phenolic compounds, e.g. 2-tert-butylphenol,
2,6-di-tertbutylphenol, 4-methyl-2,6-di-tertbutylphenol,
2,4,6-tri-tertbutylphenol, and various analogs and homologs or
mixtures thereof; one or more partially sulfurized phenolic
compounds as described in U.S. Pat. No. 6,096,695, the disclosure
of which is incorporated herein by reference; methylene-bridged
alkylphenols as described in U.S. Pat. No. 3,211,652, the
disclosure of which is incorporated herein by reference.
[0070] Antioxidants may be optionally included in the fully
formulated final inventive lubricating composition at from about
0.00 to about 5.00 weight percent, more preferably from about 0.01
weight % to about 1.00 weight %.
[0071] Component (F)--Friction Modifiers
[0072] The compositions of the present invention may optionally
contain one or more friction modifiers. These typically include
such compounds as fatty amines or ethoxylated fatty amines,
aliphatic fatty acid amides, ethoxylated aliphatic ether amines,
aliphatic carboxylic acids, glycerol esters, aliphatic carboxylic
ester-amides, aliphatic phosphonates, aliphatic phosphates,
aliphatic thiophosphonates, aliphatic thiophosphates, fatty
imidazolines, fatty tertiary amines etc., wherein the aliphatic
group usually contains above about eight carbon atoms so as to
render the compound suitably oil soluble. Also suitable are
aliphatic substituted succinimides formed by reacting one or more
aliphatic succinic acids or anhydrides with ammonia or other
primary amines.
[0073] One preferred group of friction modifiers is comprised of
the N-aliphatic hydrocarbyl-substituted diethanol amines in which
the N-aliphatic hydrocarbyl-substituent is at least one straight
chain aliphatic hydrocarbyl group free of acetylenic unsaturation
and having in the range of about 14 to about 20 carbon atoms.
[0074] Some commercially available friction modifiers which are
especially suitable in the practice of the invention are Ethomeen
T-12 an ethoxylated tallow diamine, and Ethomeen C-12, an
ethoxylated cocoalkylamine, both available from Akzo Nobel Chemical
Company.
[0075] A particularly preferred friction modifier system is
composed of a combination of at least one N-aliphatic
hydrocarbyl-substituted diethanol amine and at least one
N-aliphatic hydrocarbyl-substituted trimethylene diamine in which
the N-aliphatic hydrocarbyl-substituent is at least one straight
chain aliphatic hydrocarbyl group free of acetylenic unsaturation
and having in the range of about 14 to about 20 carbon atoms.
Further details concerning this friction modifier system are set
forth in U.S. Pat. Nos. 5,372,735 and 5,441,656, incorporated
herein by reference.
[0076] Another particularly preferred friction modifier system is
based on the combination of (i) at least one di(hydroxyalkyl)
aliphatic tertiary amine in which the hydroxyalkyl groups, being
the same or different, each contain from 2 to about 4 carbon atoms,
and in which the aliphatic group is an acyclic hydrocarbyl group
containing from about 10 to about 25 carbon atoms, and (ii) at
least one hydroxyalkyl aliphatic imidazoline in which the
hydroxyalkyl group contains from 2 to about 4 carbon atoms, and in
which the aliphatic group is an acyclic hydrocarbyl group
containing from about 10 to about 25 carbon atoms. Further details
concerning this friction modifier system are set forth in U.S. Pat.
No. 5,344,579, incorporated herein by reference.
[0077] Component (i), the di(hydroxyalkyl) aliphatic tertiary
amine, has a nitrogen atom to which are bonded two hydroxyalkyl
groups and one non-cyclic aliphatic hydrocarbyl group having 10 to
25 carbon atoms, and preferably 13 to 19 carbon atoms. The
hydroxyalkyl groups of these tertiary amines can be the same or
different, but each contains from 2 to 4 carbon atoms. The hydroxyl
groups can be in any position in the hydroxyalkyl groups, but
preferably are in the fg-position. Preferably the two hydroxyalkyl
groups in component (i) are the same, and most preferably are
2-hydroxyethyl groups. The aliphatic group of these tertiary amines
can be straight or branched chain and it can be saturated or
olefinically unsaturated and if unsaturated, it typically contains
from one to three olefinic double bonds. Component (i) can have a
single type of aliphatic group or it can comprise a mixture of
compounds having different aliphatic groups in which the average
number of carbon atoms falls within the foregoing range of from 10
to 25 carbon atoms.
[0078] From the foregoing it will be clear that component (i) can
be a single compound or a mixture of compounds meeting the
structural criteria described above.
[0079] The hydroxyalkyl aliphatic imidazolines, component (ii),
suitable for use in the practice of this invention are
characterized by having in the 1-position on the imidazoline ring a
hydroxyalkyl group that contains from 2 to 4 carbon atoms, and by
having in the adjacent 2-position on the ring a non-cyclic
hydrocarbyl group containing 10 to 25 carbon atoms. While the
hydroxyl group of the hydroxyalkyl group can be in any position
thereof, it preferably is on the .beta.-carbon atom, such as
2-hydroxyethyl, 2-hydroxypropyl or 2-hydroxybutyl. Typically the
aliphatic group is a saturated or olefinically unsaturated
hydrocarbyl group, and when olefinically unsaturated, the aliphatic
group may contain one, two or three such double bonds. Component
(ii) may be a single substantially pure compound or it may be a
mixture of compounds in which the aliphatic group has an average of
from 10 to 25 carbon atoms. Preferably the aliphatic group has 15
to 19 carbon atoms, or an average of 15 to 19 carbon atoms. Most
preferably the aliphatic group has, or averages, 17 carbon atoms.
The aliphatic group(s) may be straight or branched chain groups,
with substantially straight chain groups being preferred. A
particularly preferred compound is 1-hydroxyethyl-2-heptadec- enyl
imidazoline. One commercially available imidazoline based friction
modifier suitable for use in the present invention is Unamine O,
available from Lonza Chemical.
[0080] It will thus be clear that component (ii) can be a single
compound or a mixture of compounds meeting the structural criteria
described above.
[0081] Also suitable for use in the present invention are various
alkanol amides. One especailly suitable commercial alkanol amide is
Schercomid SLML, a lauramide diethanolamine, available from Scher
Chemicals, Inc.
[0082] Generally speaking, the fully formulated final compositions
of this invention will optionally contain up to about 1.25 wt % on
an active ingredient basis, and preferably from about 0.05 to about
1 wt % on an active ingredient basis of one or more friction
modifiers.
[0083] Component (G)--Anti-Rust
[0084] Various known anti-rust agents or additives are known for
use in transmission fluids, and are suitable for use in the fluids
according to the present invention. Especially preferred are alkyl
polyoxyalkylene ethers, such as Mazawet.RTM. 77, C-8 acids such as
Neofat.RTM. 8, oxyalkyl amines such as Tomah PA-14,
3-decyloxypropylamine, and polyoxypropylene-polyoxyethylene block
copolymers such as Pluronic.RTM. L-81.
[0085] Mixtures of the above anti-rust agents are especially
preferred. Anti-rust agents are preferably used in low quantities,
e.g from about 0.01 to about 0.10 weight %, preferably from about
0.03 to about 0.07 weight %.
[0086] Component (H)--Anti-Foam
[0087] Anti-foam agents may also be included in a fluid according
to the present invention. Various agents are known for such use.
Especially preferred are copolymers of ethyl acrylate and hexyl
ethyl acrylate, such as PC-1244, available from Solutia. Also
preferred are silicone fluids such as 4% DCF. Mixtures of anti-foam
agents are especially preferred.
[0088] Given their high activity levels, anti foam agents are
generally present in small amounts, from about 0.00-0.05 weight %,
more preferably about 0.01 weight %.
[0089] Component (I)--Diluent
[0090] If the additives are provided in an additive package
concentrate, a suitable carrier diluent is added to ease blending,
solubilizing, and transporting the additive package. The diluent
oil needs to be compatible with the base oil and the additive
package. Generally, the diluent is present in the concentrate in an
amount of between 5-20%, although it can vary widely with
application. Generally speaking, less diluent is preferable as it
lowers transportation costs and treat rates.
[0091] Component (J)--Base Oil
[0092] If the inventive composition is to be prepared as a
concentrate, then base oil may be omitted and an appropriate
adjustment made in the weight % of each of the above optional and
mandatory ingredients to prepare a suitable concentrate, taking
care that solubility and compatibility is maintained. However, if a
fully formulated fluid is to be prepared, then base oil is a
mandatory component.
[0093] The base oils used in forming the automatic transmission
fluids of this invention can be any suitable natural or synthetic
oil having the necessary viscosity properties for this usage.
Natural oils include animal oils and vegetable oils (e.g., castor
oil, lard oil etc.), liquid petroleum oils and hydrorefined,
severely hydrotreated, iso-dewaxed, solvent-treated or acid-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.
[0094] The synthetic lubricating oils suitable for use in this
invention include one of any number of commonly used synthetic
hydrocarbon oils, which include, but are not limited to,
poly-alpha-olefins, synthetic esters, alkylated aromatics, alkylene
oxide polymers, interpolymers, copolymers and derivatives thereof
where the terminal hydroxyl groups have been modified by
esterification, etherification etc., esters of dicarboxylic acids
and silicon-based oils. Thus, the base oil may be composed entirely
of a natural oil such as mineral oil of suitable viscosity or it
may be composed entirely of a synthetic oil such as a
poly-alpha-olefin oligomer of suitable viscosity.
[0095] Likewise, the base oil may be a blend of natural and/or
synthetic base oils provided that the blend has the requisite
properties for use in the formation of an automatic transmission
fluid. Ordinarily, the base oil should have a kinematic viscosity
in the range of 3 to 8 centistokes (cSt) at 100.degree. C.
Preferred automatic transmission fluids used in the practice of
this invention can be formulated without a viscosity index improver
so as to possess a kinematic viscosity of at least 3.0 cSt at
100.degree. C. and a Brookfield viscosity of no more than 20,000 cP
at -40.degree. C., or formulated using a viscosity index improver
so as to possess a kinematic viscosity of at least 6.8 cSt at
100.degree. C. and a Brookfield viscosity of no more than 20,000 cP
at -40.degree. C.
[0096] Suitable base stock oil includes, preferably, Group I, II,
and III base oils, as are known to those of skill in the art. In
certain instances, usually depending on the final use of the
lubricant composition according to the present invention, Group I
is preferred, and in other instances, Group II and III are
preferred.
[0097] Group I base stocks contain less than 90% saturates (as
determined by ASTM D 2007) and/or greater than 0.03 percent sulfur
(as determined by ASTM D 2622, D 4294, D 4927, or D 3120) and have
a viscosity index greater than or equal to 80 and less than 120 (as
determined by ASTM D 2270).
[0098] Group II base stocks contain greater than or equal to 90%
saturates and less than or equal to 0.03% sulfur and have a
viscosity index greater than 80 and less than 120 using the above
noted test methods. Group II + oils may also be used. These are
oils which have a VI at the high end of the VI spectrum, e.g. about
120.
[0099] Group III base stocks contain greater than or equal to 90
percent saturates and less than or equal to 0.03% sulfur and have a
viscosity index greater than or equal to 120 using the tests noted
above.
[0100] In another embodiment, the transmission fluid contains less
than 5% poly-alpha-olefins (PAO) and is more preferably PAO
free.
[0101] Base oil usually comprises the balance to 100 weight % of
the fully formulated oil after all other additives are
considered.
[0102] Component (K)--Viscosity Index Improver
[0103] The compositions of the present invention optionally, but
preferably, contain a viscosity index improver (VII). Preferred
VIIs include, but are not limited to, olefin copolymer VIIs,
polyalkylmethacrylate VIIs and styrene-maleic ester VIIs. Of these,
polyalkylmethacrylate VIIs are particularly preferred. The
viscosity index improver is supplied in the form of a solution in
an inert solvent, typically a mineral oil solvent, which usually is
a severely refined mineral oil. The viscosity index improver
solution as received often will have a boiling point above
200.degree. C., and a specific gravity of less than 1 at 25.degree.
C. Preferably, the viscosity index improver will have sufficient
shear stability such that the finished composition possesses a
kinematic viscosity of at least 5, and more preferably at least
6.8, cSt at 100.degree. C. after 40 cycles in the FISST (Fuel
Injector Shear Stability Test) of ASTM D-5275.
[0104] On an active ingredient basis (i.e., excluding the weight of
inert diluent or solvent associated with the viscosity index
improver as supplied), the finished fluid compositions of this
invention will normally contain in the range of about 0 to about 15
wt % of the polymeric viscosity index improver. Small departures
from this range may be resorted to as necessary or desirable in any
given situation.
[0105] Suitable materials for use as component (K) include
styrene-maleic ester VIIs such as LUBRIZOL.RTM. 3702, LUBRIZOL.RTM.
3706 and LUBRIZOL.RTM. 3715 available from The Lubrizol
Corporation; polyalkylmethacrylate VIIs such as those available
from RHM GmbH (Darmstadt, Germany) under the trade designations:
VISCOPLEX.RTM. 5543, VISCOPLEX.RTM. 5548, VISCOPLEX.RTM. 5549,
VISCOPLEX.RTM. 5550, VISCOPLEX.RTM. 5551 and VISCOPLEX.RTM. 5151,
from Rohm & Haas Company (Philadelphia, Pa.) under the trade
designations ACRYLOID.RTM. 1277, ACRYLOID.RTM. 1265 and
ACRYLOID.RTM. 1269, and from Ethyl Corporation (Richmond, Va.)
under the trade designation HiTEC.RTM. 5710 viscosity index
improver; and olefin copolymer VIIs such as HiTEC.RTM. 5747 VII,
HiTEC.RTM. 5751 VII, HiTEC.RTM. 5770 VII and HiTEC.RTM. 5772 VII
available from Ethyl Corporation and SHELLVIS.RTM. 200 available
from Shell Chemical Company. Mixtures of the foregoing products can
also be used as well as dispersant and dispersant/antioxidant
VIIs.
[0106] Preferably, the viscosity index improver will be provided as
a hydrocarbon solution having a polymer content in the range of
from about 25 to about 80 wt % and a nitrogen content in the range
of about 0 to about 0.5 wt %. Such products preferably exhibit a
permanent shear stability index (a PSSI value) using ASTM test
method D-3945A of no higher than about 75, preferably 50 or less,
and most preferably 35 or less.
[0107] Especially preferred is a dispersant polymethacrylate
viscosity index improver such as HiTEC.RTM. 5738, or a non
dispersant polymethacrylate viscosity index improver such as
HiTEC.RTM. 5739, both products of Ethyl Corporation, Richmond Va.
Especially preferred is a mixture of dispersant and non-dispersant
viscosity index improvers.
[0108] Quantitatively, the viscosity index improver may be present
in an amount of from 0-25% by weight, preferably from 5-20% by
weight.
[0109] Component (L)--Dye
[0110] It is preferred to add a colorant to the fluid to give it a
unique character which is detectable. Generally, azo class dyes are
used, such as C.I. Solvent Red 24 or C.I. Solvent Red 164, as set
forth in the "Colour Index" of the American Association of Textile
Chemists and Colorists and the Society of Dyers and Colourists
(U.K.) which is incorporated herein by reference. For automatic
transmission fluids, Automate Red Dye is especially preferred. Dye
is present in a very minimal amount, of 200-300 ppm in the finished
oil.
[0111] Component (M)--Seal Swell Agents
[0112] The automatic transmission fluids of the present invention
may further include seal swell agents. Seal swell agents such as
ester, sulfones, alcohols, alkylbenzenes, substituted sulfolanes,
aromatics, or mineral oils cause swelling of elastomeric materials
used as seals in engines and automatic transmissions.
[0113] Alcohol-type seal swell agents are generally low volatility
linear alkyl alcohols, such as decyl alcohol, tridecyl alcohol and
tetradecyl alcohol.
[0114] Alkylbenzenes useful as seal swell agents include
dodecylbenzenes, tetradecylbenzenes, dinonyl-benzenes,
di(2-ethylhexyl)benzene, and the like.
[0115] Substituted sulfolanes (e.g. those described in U.S. Pat.
No. 4,029,588, incorporated herein by reference) are likewise
useful as seal swell agents in compositions according to the
present invention.
[0116] Mineral oils useful as seal swell agents in the present
invention include low viscosity mineral oils with high naphthenic
or aromatic content.
[0117] Aromatic seal swell agents include the commercially
available Exxon Aromatic 200 ND seal swell agent.
[0118] Commercially available examples of mineral oil seal swell
agents include Exxon.RTM. Necton.RTM.-37 (FN 1380) and Exxon.RTM.
Mineral Seal Oil (FN 3200).
[0119] When used in the ATF of the present invention, a seal swell
agent will typically comprise from about 1 to about 30 wt. %,
preferably from about 1 to about 20 wt. %, most preferably from
about 1 to about 10 wt. %, based on the total weight of ATF.
[0120] Component (N)--Additional Corrosion Inhibitors
[0121] The automatic transmission fluids of the present invention
may further include additional corrosion inhibitors. Other suitable
additional inhibitors of copper corrosion include ether amines;
polyethoxylated compounds such as ethoxylated amines, ethoxylated
phenols, and ethoxylated alcohols; imidazolines; and the like.
[0122] Thiazoles, triazoles and thiadiazoles may also be used in
the present invention. Examples include benzotriazole;
tolyltriazole; octyltriazole; decyltriazole; dodecyltriazole;
2-mercaptobenzothiazole; 2,5-dimercapto-1,3,4-thiadiazole;
2-mercapto-5-hydrocarbylthio-1,3,4-thia- diazoles; and
2-mercapto-5-hydrocarbyldithio -1,3,4-thiadiazoles. The preferred
compounds are the 1,3,4-thiadiazoles, especially the
2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazoles, a number of
which are available as articles of commerce. These may be present
in an amount of from 0.00 to 0.50 weight percent, more preferably
from about 0.01 to about 0.10 weight percent, based on the final
formulation.
[0123] Component (O)--Anti Wear/Extreme Pressure Additive
[0124] The automatic transmission fluids of the present invention
may further include anti-wear/extreme pressure additives.
[0125] When the desired phosphorus content of the finished fluid is
not completely supplied by use of a phosphorus-containing ashless
dispersant (or a boron- and phosphorus-containing ashless
dispersant), the remainder of the phosphorus content is preferably
supplied by inclusion in the composition of one or more
phosphorus-containing esters or acid-esters such as oil-soluble
organic phosphites, oil-soluble organic acid phosphites,
oil-soluble organic phosphates, oil-soluble organic acid
phosphates, oil-soluble phosphoramidates. Examples include
trihydrocarbyl phosphates, trihydrocarbyl phosphites, dihydrocarbyl
phosphates, dihydrocarbyl phosphonates or dihydrocarbyl phosphites
or mixtures thereof, monohydrocarbyl phosphates, monohydrocarbyl
phosphites, and mixtures of any two or more of the foregoing.
Oil-soluble amine salts of organic acid phosphates are a preferred
category of auxiliary phosphorus-containing additives for use in
the fluids of this invention. Sulfur-containing analogs of any of
the foregoing compounds can also be used, but are less preferred.
Most preferred as a commercially-available auxiliary phosphorus
additive is an amine phosphate antiwear/ extreme pressure agent
available from Ciba-Geigy Corporation as Irgalube.RTM. 349.
[0126] The extreme pressure/anti wear additive is preferably
present in the final fully-formulated fluid in an amount of from
0.00 to about 1.00 weight %, more preferably from about 0.25 to
about 1.00 weight %.
[0127] In selecting any of the foregoing optional additives, it is
important to ensure that the selected component(s) is/are soluble
or stably dispersible in the additive package and finished ATF
composition, are compatible with the other components of the
composition, and do not interfere significantly with the
performance properties of the composition, such as the friction,
viscosity and/or shear stability properties, needed or at least
desired in the overall finished composition.
[0128] In general, the ancillary additive components are employed
in the oils in minor amounts sufficient to improve the performance
characteristics and properties of the base fluid. The amounts will
thus vary in accordance with such factors as the viscosity
characteristics of the base fluid employed, the viscosity
characteristics desired in the finished fluid, the service
conditions for which the finished fluid is intended, and the
performance characteristics desired in the finished fluid. However,
generally speaking, the following concentrations (weight percent
unless otherwise indicated) of the additional components (active
ingredients) in the base fluids are illustrative:
1 Component Typical Range Preferred Range D 1.00-15.00 1.00-8.00 E
0.1-5.00 0.25-3.00 F .ltoreq.1.25 0.05-1.00 G .ltoreq.0.02
0.01-0.10 H .ltoreq.0.05 0.005-0.02 I .ltoreq.25 (in the 5.00-20.00
(in the concentrate) concentrate) J Balance Balance K 0.00-25.00
5.00-20.00 L 0-400 ppm 200-300 ppm M 1.00-30.00 5.00-15.00 N
0.00-0.50 0.01-0.10 O 0.00-1.00 0.25-1.00
[0129] It will be appreciated that the individual components
employed can be separately blended into the base fluid or can be
blended therein in various subcombinations, if desired. Ordinarily,
the particular sequence of such blending steps is not critical.
Moreover, such components can be blended in the form of separate
solutions in a diluent. It is preferable, however, to blend the
additive components used in the form of a concentrate, as this
simplifies the blending operations, reduces the likelihood of
blending errors, and takes advantage of the compatibility and
solubility characteristics afforded by the overall concentrate.
[0130] Additive concentrates can thus be formulated to contain all
of the additive components and if desired, some of the base oil
component, in amounts proportioned to yield finished fluid blends
consistent with the concentrations described above. In most cases,
the additive concentrate will contain one or more diluents such as
light mineral oils, to facilitate handling and blending of the
concentrate. Thus concentrates containing up to about 50% by weight
of one or more diluents or solvents can be used, provided the
solvents are not present in amounts that interfere with the low and
high temperature and flash point characteristics and the
performance of the finished power transmission fluid composition.
In this connection, the additive components utilized pursuant to
this invention should be selected and proportioned such that an
additive concentrate or package formulated from such components
will have a flash point of 170.degree. C. or above, and preferably
a flash point of at least 180.degree. C., using the ASTM D-92 test
procedure.
EXAMPLES
[0131] Illustrative compositions suitable for use in the practice
of this invention are presented in the following Examples, wherein
all parts and percentages are by weight unless specified
otherwise.
[0132] The fluids prepared in the Examples were then subjected to
testing under the commonly known FZG test. The test is conducted in
the FZG gear rig test machine. This test, IP (Institute of
Petroleum) 334/79, which is incorporated herein by reference,
measures lubricity, and in the test, two steel spin gears are
rotated together for a series of 75 minute stages. The relative
torque between the gears is increased by a fixed amount after each
stage and the gears are run together for a given period after which
they are examined for wear or damage. The result of the test is
quoted in terms of the final pass stage and the first fail stage.
The test is technically equal to ASTM D 5182-97. This test can be
conducted at selected temperatures, nominally 90 degrees C. and 150
degrees C.
[0133] Thus, one embodiment of the present invention comprises an
automatic transmission fluid, containing (1) a major amount of a
base oil and (2) a minor amount of an additive comprising (A) at
least 0.025 wt %, preferably 0.05 wt %, based on the fluid, of an
ashless dialkyl thiadiazole, and (B) a sulfurized fat, sulfurized
fatty acid, sulfurized fatty acid ester or a mixture thereof.
2TABLE 1 Composition and Testing of Examples Comp. Comp. Comp.
Comp. Comp. Component Ex. 1 Ex. 1* Ex. 2* Ex. 3* Ex. 4* Ex. 5*
Description A 0.10*** 0.00 0.00 0.10 0.00 0.00 Ashless Dialkyl
Thiadiazole**** X 0.00 0.10 0.00 0.00 0.00 0.00 Ashless Monoalkyl
Thiadiazole***** B 0.50 0.50 0.50 0.00 0.00 0.00 Sulfurized fatty
acid ester C 0.05 0.05 0.05 0.05 0.05 0.05 Low base Calcium Phenate
D,E,F, 7.65 7.65 7.65 7.65 7.65 7.65 Dispersant/Inhibitor G,H,I
concentrate J 78.88 78.88 78.98 79.38 79.48 79.48 Base oil K 12.80
12.80 12.80 12.80 12.80 12.80 Viscosity index improver L 0.02 0.02
0.02 0.02 0.02 0.02 Red dye Total 100.00 100.00 100.00 100.00
100.00 100.00 FZG Pass** 11.33 10.83 7.5 8 6 9 Kinematic 7.56 7.52
7.46 7.34 7.31 7.29 Viscosity 100 C. (cSt) Brookfield 13280 11900
11600 10440 10180 9540 Viscosity -40 C. (cPs) *Comparative Example,
Not within Scope of Invention **Cumulative Average of Tests. ***All
in weight % based on finished fluid ****HiTEC .RTM. 4313, Ethyl
Corporation, Richmond, Virginia *****HiTEC .RTM. 4312, Ethyl
Corporation, Richmond, Virginia
[0134] It is clear, upon examination of the data presented, that
the compositions of the present invention exhibit superior
performance in the FZG test, passing on average above stage 11.
[0135] Thus it is now possible, as evidenced by the data presented,
to formulate power transmission fluids which exhibit excellent FZG
wear characteristics sufficient to consistently pass the FZG wear
test beyond stage 11.
[0136] This invention is susceptible to considerable variation in
its practice. Accordingly, this invention is not limited to the
specific exemplifications set forth hereinabove. Rather, this
invention is within the spirit and scope of the appended claims,
including the equivalents thereof available as a matter of law.
[0137] The patentee does not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part of the
invention under the doctrine of equivalents.
* * * * *