Note: Descriptions are shown in the official language in which they were submitted.
- 2 ~ 1~8~0~
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a lubricating composition,
and, in particular, to manual transmission fluids.
2. Description of the Art Practices
Transmission fluids, particularly those for synchro-
mesh manual transmissions, have typically been based upon
high weight mineral oils, e.g., 80 weight oil, engine
oils, differential oils and automatic transmission fluids.
The lighter of these oils, e.g., automatic transmission
fluid, thins out too much at the high temperatures reached
during summertime driving resulting in objectional gear
noise. While the heavier of these oils are acceptable
under normal summertime driving conditions, difficulties
are often encountered in cold weather conditions. The
viscosity of the heavier mineral oils increases
substantially in the winter due to low temperatures. The
shifting characteristics for the manual transmission are
then significantly hindered due to the thickened oil. The
hindered operation of the manual transmission requires
greater effort to shift the gears. In extreme cases, this
has resulted in a broken shifting lever.
A second problem which faces a synchromesh
transmission is that of double detent or double bump.
This phenomena results when the static coefficient of
friction is too high and the cone and ring cannot engage
due to insufficient slippage to allow smooth engaging. A
further problem arises if the dynamic coefficient of
friction is too low as clashing is observed. The clashing
arises because the relative velocity of the blocker ring
and cone assembly does not go to zero before engagement.
Given a resurgence of manual transmissions in an
attempt to conserve fuel and in high performance vehicles
using manual transmissions, it becomes imperative that the
problems of double detent, low dynamic coefficient of
-- 3 --
1~80404
friction and high static coefficient of friction be
solved. The present invention provides a solution to
double detent through the formulation of a manual
transmission fluid which exhibits high dynamic friction
properties as well as low static friction properties.
Various components of the present invention are known
in lubricating fluids. For instance, United States Patent
4,031,023 issued June 21, 1977 to Musser and Koch,
discloses the use of viscosity improvers to impart a
liquid character to a lubricating composition. Musser et
al also discloses synthetic lubricating oils, extreme
pressure (EP) agents and dispersants. The term
dispersants as utilized by Musser et al include materials
which suspend or disperse sludge and which are described
as being oil-soluble, and stably dispersible in
lubricating compositions.
Heilman et al in United States Patent 3,957,664
issued May 18, 1976, discuss the use of olefin based
synthetic lubricants. In particular, internal olefins or
mixtures of internal olefins are combined with di-t-
butyl-p-cresol to obtain a high temperature lubricant.
Wiley et al in United States Patent 3,944,495 issued
March 16, 1976, discuss various di-alkyl dithiophosphates
obtained from oxylated long, straight-chain alcohols,
acids or mercaptans and the use of such materials in
lubricating oils. Wiley et al is concerned with automatic
transmission fluids and, in particular, zinc salts which
are stated to give anti-corrossion and anti-wear
properties to the automatic transmission.
United States Patent 4,119,550 issued October 10,
1978 to Davis and Holden describes sulfurized olefins as
lubricant additives. A further disclosure of sulfurized
olefins for use in lubricants is found in United States
Patent 4,119,549 issued October 10, 1978 to Davis.
Further disclosures of sulfurized olefins for
lubricant formulations are found in United States Patent
4,344,854 to Davis et al issued August 17, 1982. Still
1280404
-- 4 --
further disclosures of sulfurized products useful in
lubricants are found in Davis, United States Patent
4,191,659 issued March 4, 1980.
The use of calcium alkyl benzene sulfonates and
polyolefins in a lubricant is found in United States patent
4,172,855 issued October 30, 1979 to Shubkin et al.
Horodysky, in United States Patent 4,529,528 issued July 16,
1985 describes borated amine-phosphite reaction products
which are useful in lubricants and fuels. Horodysky also
discloses various olefin polymers which are stated to be
useful in synthetic oils.
Howie et al, in United States Patent 4,525,289 issued
June 25, 1985, discloses various lubricating formulations
utilizing overbased calcium sulfonate and overbased
magnesium sulfonate. Trimers of alpha-decene are shown in
combination with the sulfonate salts and as well with
dispersants, foam inhibitors and amides in Howie et al.
The foregoing references, while generally applicable to
lubricating compositions, do not specifically discuss the
issue of obtaining good dynamic and static properties in a
manual transmission fluid. The present invention deals with
obtaining a manual transmission fluid having outstanding
static and dynamic frictional properties.
Throughout the specification and claims, percentages
and ratios are by weight, temperatures are in degrees
Celsius, and pressures are in KPascals over ambient unless
otherwise indicated.
A
128~404
SUMMARY OF THE INVENTION
The present invention describes a synthetic lubricant
mixture suitable for a manual transmission fluid
comprising:
(a) an alkaline earth metal salt selected from
the group consisting of sulfonates, phenates, oxylates,
carboxylates and mixtures thereof;
(b) a friction modifier selected from the group
consisting of fatty phosphites, borated fatty epoxides,
borated glycerol monocarboxylates, borated alkoxylated
fatty amines and mixtures thereof;
(c) a sulfurized olefin; and
(d) a synthetic lubricant.
128q)404
DETAILED DESCRIPTION OF THE INVENTION
The first aspect of the present invention is the
alkaline earth metal salt which has been found
particularly useful to assist in the frictional properties
in the manual transmission fluid compositions. The salt
may be a phenate, oxylate, carboxylate or preferably a
sulfonate. It has been determined that the preferred salt
is a magnesium sulfonate. Calcium salts are adequate for
usage alone in the present invention but when used are
preferably in combination with the magnesium sulfonate
salts. Barium salts may also be used herein.
The sulfonate salts are those having a substantially
oleophilic character and which are formed from organic
materials. Organic sulfonates are well known materials in
the lubricant and detergent arts. The sulfonate compound
should contain on average from about 10 to about 40 carbon
atoms, preferably from about 12 to about 36 carbon atoms
and preferably from about 14 to about 32 carbon atoms on
average. Similarily, the phenates, oxylates and
carboxylates have a substantially oleophilic character.
While the present invention allows for the carbon
atoms to be either aromatic or in a paraffinic
configuration, it is highly preferred that alkylated
aromatics be employed. While naphthalene based materials
may be employed, the aromatic of choice is the benzene
moiety.
The most preferred composition is thus a mono-
sulfonated alkylated benzene, and is preferably the
mono-alkylated benzene. Typically, alkyl benzene
fractions are obtained from still bottom sources and are
mono- or di-alkylated.
It is believed, in the present invention, that the
mono-alkylated aromatics are superior to the di-alkylated
aromatics in overall properties. The use of mono-
functional (e.g., mono-sulfonated) materials avoids
_ -- 7 --
128~)404
crosslinking of the molecules with less precipitation of
the salt in the transmission.
It is desired that a mixture of mono-alkylated
aromatics (benzene) be utilized to obtain the mono-
alkylated salt (benzene sulfonate) in the presentinvention. The mixtures wherein a substantial portion of
the composition contains polymers of propylene as the
source of the alkyl groups assists in the solubility of
the salt in the manual transmission fluid.
The amount of the salt utilized in the present
invention is typically from about 0.5% to about 8%,
preferably from about 0.75% to about 6%, and most
preferably from about 1% to about 5% by weight of the
total composition. For maximum effectiveness, the salt
should be greater than 3% by weight of the composition.
It is also desired that the salt be "overbased". By
overbasing, it is meant that a stoichiometric excess of
the alkaline earth metal be present over that required to
neutralize the anion of the salt. The excess metal from
overbasing has the effect of neutralizing acids which may
build up in the lubricant. A second advantage is that the
overbased salt increases the dynamic coefficient of
friction. Typically, the excess alkaline earth metal will
be present over that which is required to neutralize the
anion at about 10:1 to 30:1, preferably 11:1 to 18:1 on an
equivalent basis.
The second required component of the manual trans-
mission fluid of the present invention is a friction
modifier such as a fatty phosphite. The phosphites are
generally of the formula (RO)2PHO. The preferred
dialkylated phosphite as shown in the preceding formula is
typically present with a mono-alkylated phosphite of the
formula (RO)(HO)PHO. Both of these phosphites are
concomitantly produced and thus mixture of the mono-
phosphite and the di-phosphite is present.
The mixtures of the phosphites are typically such
that the weight ratio of the mono-phosphite to the
1~8~)404
di-phosphite is from about 2:1 to about 1:4 by weight. It
is, of course, highly desirable that the di-phosphite be
present in an excess over the mono-phosphite.
In the above structure of the phosphite, the term "R"
has been referred to as an alkyl group. It is, of course,
possible that the alkyl is alkenyl and thus the terms
"alkyl" and "alkylated", as used herein, embrace other
than saturated alkyl groups within the phosphite. The
phosphite utilized herein is thus one having sufficient
hydrocarbyl groups to render the phosphite substantially
oleophilic and further that the hydrocarbyl groups are
preferably substantially unbranched.
It is preferred that the phosphite contain from about
10 to about 24 carbon atoms in each of the fatty radicals
described as "R". The inclusion of substantial amounts of
the mono-alkylated phosphite require that the radical "R"
contain a larger number of carbon atoms. Preferably, the
fatty phosphite contains from about 12 to about 22 carbon
atoms in each of the fatty radicals, most preferably from
about 16 to about 20 carbon atoms in each of the fatty
radicals. It is highly preferred that the fatty phosphite
be formed from oleyl groups, thus having 18 carbon atoms
in each fatty radical.
Other friction modifiers which are useful herein are
borated fatty epoxides, borated glycerol monocarboxylates,
and borated alkoxylated fatty amines. Borated fatty
epoxides are known from Canadian Patent 1,188,704 issued
June 11, 1985 to Davis. The oil-soluble boron-containing
compositions of Davis are prepared by reacting at a
temperature from about 80C to about 250C,
(A) at least one of boric acid or boron trioxide
with
(B) at least one epoxide having the formula
R R C[O]CR R
- -- 9
128~04
- wherein each of Rl, R2, R3 and R4 is hydrogen or an
aliphatic radical, or any two thereof together with the
epoxy carbon atôm or atoms to which they are attached,
form a cyclic radical, said epoxide containing at least 8
carbon atoms.
As will be apparent, the borated fatty epoxides are
characterized by the method for their preparation which
involves the reaction of two materials. Reagent A may be
boron trioxide or any of the various forms of boric acid,
including metaboric acid (HBO2), orthoboric acid (H3BO3)
and tetraboric acid (H2B4O7). Boric acid, and especially
orthoboric acid, is preferred.
Reagent B is at least one epoxide having the above
formula and containing at least 8 carbon atoms. In the
formula, each of the R values is most often hydrogen or an
aliphatic radical with at least one being an aliphatic
radical containing at least 6 carbon atoms. The term
"aliphatic radical" includes aliphatic hydrocarbon
radicals (e.g., hexyl, heptyl, octyl, decyl, dodecyl,
tetradecyl, stearyl, hexenyl, oleyl), preferably free from
acetylenic unsaturation; substituted aliphatic hydrocarbon
radicals including substituents such as hydroxy, nitro,
carbalkoxy, alkoxy and alkylthio (especially those
containing a lower alkyl radical; i.e., one containing 7
carbon atoms or less); and hetero atom-containing radicals
in which the hetero atoms may be, for example, oxygen,
nitrogen or sulfur. The aliphatic radicals are preferably
alkyl radicals, and more preferably those containing from
about 10 to about 20 carbon atoms. Mixtures of epoxides
may be used; for example, commercial available C14 16 or
C14 18 epoxides and the like, wherein R is a mixture of
alkyl radicals having two less carbon atoms than the
epoxide. Most desirably, Rl is a straight-chain alkyl
radical and especially the tetradecyl radical.
35Further useful epoxides are those in which any two of
the R radicals form a cyclic radical, which may be
alicyclic or heterocyclic. Examples are n-butylcyclo-
10 --
~Z8 [)40~
pentene oxide, n-hexylcyclohexene oxide, methylenecyclo-
octene oxide and 2-methylene-3-n-hexyltetrahydrofuran
oxide.
The borated fatty epoxides may be prepared by merely
blending the two reagents and heating them at a
temperature from about 80 to about 250C., preferably
from about 100 to about 200C., for a period of time
sufficient for reaction to take place. If desired, the
reaction may be effected in the presence of a substan-
tially inert, normally liquid organic diluent such astoluene, xylene, chlorobenzene, dimethylformamide or the
like, but the use of such diluents is usually unnecessary.
During the reaction, water is evolved and may be removed
by distillation.
The molar ratio of reagent A to reagent B is
generally between about 1:0.25 and about 1:4. Ratios
between about 1:1 and about 1:3 are preferred, with 1:2
being an especially preferred ratio.
It is frequently advantageous to employ a catalytic
amount of an alkaline reagent to facilitate the reaction.
Suitable alkaline reagents include inorganic bases and
basic salts such as sodium hydroxide, potassium hydroxide
and sodium carbonate; metal alkoxides such as sodium
methoxide, potassium t-butoxide and calcium ethoxide;
heterocyclic amines such as piperidine, morpholine and
pyridine; and aliphatic amines such as n-butylamine,
di-n-hexylamine and tri-n-butylamine. The preferred
alkaline reagents are the aliphatic and heterocyclic
amines and especially tertiary amines. When the preferred
method involving the "heel" is used, the alkaline reagent
is typically added to the blend of the "heel" with reagent
A.
The molecular structures of the compositions of this
invention are not known with certainty. During their
preparation, water is evolved in near-stoichiometric
amounts for conversion of boric acid to boron trioxide
when reagent A is boric acid, and gel permeation
1~8~)4C~d~
chromatography of the composition prepared from boric acid
and a C16 alpha-olefin oxide mixture in a 1:2 molar ratio
indicates the presence in substantial amounts of three
constituents having approximate molecular weights of 400,
600 and 1200.
The borated amines are generally known from European
published applications 84 302 342.5 filed April 5, 1984
and 84 307 355.2 filed October 25, 1984, both authored hy
Reed Walsh.
The borated amine friction modifiers are conveniently
prepared by the reaction of a boron compound selected from
the group consisting of boric acid, boron trioxide and
boric acid esters of the formula B(OR)3 wherein R is a
hydrocarbon-based radical containing from 1 to about 8
carbon atoms and preferably from about 1 to about 4 carbon
atoms with an amine selected from the group consisting of
hydroxy containing tertiary amines corresponding to the
formulae
B-(OR )XNR R (A)
and
B-[(OR )xZ]3 (B)
wherein Z is an imidazolene radical, Rl in each formula is
a lower alkylene based radical containing from 1 to about
8 carbon atoms, R2 is a radical selected from the group
consisting of hydrocarbon based radicals containing from 1
to about 100 carbon atoms and alkoxy radicals of the
structure H(oR4)y~ where R is a lower alkylene based
radical containing from 1 to about 8 carbon atoms, R and
R (pendent from the ethylenic carbon in the 2 position in
the imidazolene (Z) radical) are each hydrocarbon based
radicals containing from 1 to about 100 carhon atoms, x
and y are each an integer ranging from at least 1 to about
50 and the sum of x+y is at most 75. In a preferred
embodiment, the amines useful in preparing the
organo-borate additive compositions are those tertiary
amines corresponding to (A) above wherein R is an alkoxy
- - 12 -
~286~4~
radical of the structure H(oR4)V- wherein R is a lower
alkylene radical containing from 1 to about 8 carbon atoms
and R3 is an aliphatic based hydrocarbon radical
containing from about 8 to about 25 carbon atoms, and
preferably from about 10 to about 20 carbon atoms and x
and y are each an integer ranging from at least 1 to about
25 and wherein the sum of x+y is at most 50, and those
tertiary amines containing the imidazoline structure above
wherein R1 is a lower alkylene based radical containing
from 1 to about 8 carbon atoms, R5 is an aliphatic based
hydrocarbon radical, preferably alkyl or alkenyl based
radical, containing from about 8 to about 25 carbon atoms
and preferably from about 10 to about 20 carbon atoms.
Preferred tertiary amines useful in preparing the multi-
functional organo-borate additive compositions are those
tertiary amines corresponding to formula (A) above wherein
R2 is an alkoxy radical of the structure H(oR4) -, wherein
R1 and R4 are individually ethylene or propylene radicals,
R3 is an alkyl or an alkenyl based hydrocarbon radical
containing from about 10 to about 20 carbon atoms, x and y
are each an integer ranging from at least 1 to about 9 and
preferably from at least 1 to about 5 and the sum of x+y
is at most 10 and preferably at most 5, i.e., the sum of
x+y ranges from about 2 to about 10 and preferably from
about 2 to about 5 respectively.
As used herein, the term "hydrocarbon-based radical"
denotes a radical having a carbon atom directly attached
to the remainder of the molecule and having predominantly
hydrocarbon character within the context of this
invention. Such radicals include the following:
(1) Hydrocarbon radicals; that is, aliphatic, (e.g.,
alkyl or alkenyl), alicyclic (e.g., cycloalkyl or cyclo-
alkenyl), aromatic, aliphatic- and alicyclic-substituted
aromatic, aromatic-substituted aliphatic and alicyclic
radicals, and the like, as well as cyclic radicals whereln
the ring is completed through another portion of the
molecule (that is, any two indicated hydrocarbon radicals,
~ 13 -
1~8~)40~
e.g., R2 and R3, may together form an alicyclic radical
and such radical may contain heteroatoms such as nitrogen,
oxygen and sulfur). Such radicals are known to those
skilled in the art; representative examples are examples
of such radicals as represented by R2, R3 and R5 in the
formulae above include methyl, ethyl, butyl, hexyl, octyl,
decyl, dodecyl, tetradecyl, octadecyl, eicosyl,
cyclohexyl, phenyl and naphthyl and the like including all
isomeric forms of such radicals and when R2 and R3
together form an alicyclic radical, then examples of such
radicals include morpholinyl, piperidyl, piperazinyl,
phenothiazinyl, pyrrolyl, pyrrolidyl, thiazolidinyl and
the like.
(2) Substituted hydrocarbon radicals; that is,
radicals containing non-hydrocarbon substituents which, in
the context of this invention, do not alter the predomin-
antly hydrocarbon character of the radical. Those skilled
in the art will be aware of suitable substituents;
representative examples are hydroxy (HO-); alkoxy (RO-);
carbalkoxy (RO2C-); acyl [RC(O)-]; acyloxy (RCO2-);
carboxamide (H2NC(O)-); acylimidazyl; [RC(NR)-]; nitro-
(-NO2); and alkylthio(RS-) and halogen atoms (e.g., F, Cl,
Br and I).
Hetero radicals; that is, radicals which, while
predominantly hydrocarbon, contain atoms other than carbon
present in a chain or ring otherwise composed of carbon
atoms. Suitable hetero atoms will be apparent to those
skilled in the art and include, for example, nitrogen,
oxygen and sulfur.
In general, no more than about three substituents or
hetero atoms, and preferably no more than one, will be
present for each 10 carbon atoms in the hydrocarbon-based
radical.
Terms such as "alkyl-based radical," "alkenyl-based
radical" and alkylene-based radical" and the like have
analogous meanings with respect to alkyl and aryl radicals
and the like.
1~86)~0~
Representative examples of the tertiary amine
compounds useful in preparing the organo-borate compounds
of this invention include monoalkoxylated amines such as
dimethylethanolamine, diethylethanolamine, dibutylethanol-
amine, diisopropylethanolamine, di(2-ethylhexyl)
ethanolamine, phenylethylethanolamine, dibutylisopropanol-
amine, dimethylisopropanolamine and the like and poly-
alkoxylated amines such as methyldiethanolamine, ethyl-
diethanolamine, phenyldiethanolamine, diethyleneglycol
mono-N-morpholinoethyl ether, N-(2-hydroxyethyl)thiazoli-
dine, 3-morpholinopropyl-(2-hydroxyethyl)cocoamine, N-(2-
hydroxy-ethyl)-N-tallow-3-aminomethylpropionate, N-(2-
hydroxyethyl)-N-tallow acetamide, 2-oleoylethyl(2-
hydroxyethyl) tallowamine, N-[N'-dodecenyl; N'-[2-hydroxy-
ethylaminoethyl] thiazole, 2-methoxyethyl-(2-hydroxyethyl)
tallowamine, 1-[N-dodecenyl; N-2-hydroxyethyl-aminoethyl]
imidazole, N-[N'-octadecenyl-N'-2-hydroxyethyl-aminoethyl]
phenothiazine, 2-hydroxydicocamine, 2-heptadecenyl-1-(2-
hydroxyethylimidazoline, 2-dodecyl-1-(5-hydroxypentyl-
imidazoline), 2-(3-cyclohexylpropyl)-1-(2-hydroxyethyl-
imidazoline) and the like.
An especially preferred class of tertiary amines
useful in preparing the organo-borate compounds of the
invention is that constituting the commercial alkoxylated
fatty amines known by the trademark "ETHOMEEN" and
available from the Armak Company. Representative examples
of these ETHOMEEN is ETHOMEEN C/12 (bis[2-hydroxyethyl]
cocoamine); ETHOMEEN C/20(polyoxyethylene[10]cocoamine);
ETHOMEEN S/12(bis[2-hydroxyethyl]soyamine); ETHOMEEN
T/12(bis[2-hydroxyethyl]tallowamine); ETHOMEEN T/15-
(polyoxyethylene-[5]tallowamine); ETHOMEEN 0/12(bis[2-
hydroxyethyl]oleyl-amine; ETHOMEEN 18/12(bis[2-hydroxy-
ethyl]octadecylamine; ETHOMEEN 18/25 (polyoxyethylene-
[15]octadecylamine and the like. Of the various ETHOMEEN
- 15 -
~L~8~)~0~
compounds useful in reparing the organo-borate additive
compounds of the invention, ETHOMEEN T/12 is most
preferred.
If desired, the tertiary amine reactants represented
by formulae (A) and tB) above may be reacted first with
elemental sulfur to sulfurize any carbon-to-carbon double
bond unsaturation which may be present in the hydrocarbon
based radicals R2, R3 and R5 when these radicals are, for
example, alkenyl radicals (e.g., fatty oil or fatty acid
radicals). Generally the sulfurization reaction will be
carried out at temperatures ranging from about 100C. to
about 250C. and preferably from about 150C. to about
200C. The molar ratio of sulfur to amine can range from
about 0.5:1.0 to about 3.0:1.0 and preferably 1.0:1Ø
Although, generally no catalyst is required to promote
sulfurization of any carbon-to-carbon double bond
unsaturation which may be present in any tertiary amine
reactant useful in preparing the organo-borate
compositions of this invention, catalysts may be employed,
if desired. If such catalysts are employed, preferably
such catalysts are tertiary hydrocarbon substituted
amines, most preferably, trialkylamines. Representative
examples of which include tributylamine, dimethyloctyl-
amine, triethylamine and the like.
The organo-borate additive friction modifiers can be
prepared by adding the boron reactant, preferably boric
acid, to at least one of the above defined tertiary amine
reactants, in a suitable reaction vessel, and heating the
resulting reaction mixture at a temperature ranging from
about 50 to about 300C with continuous stirring. The
reaction is continued until by-product water ceases to
evolve from the reaction mixture indicating completion of
the reaction. The removal of by-product water is
facilitated by either blowing an inert gas, such as
nitrogen, over the surface of the reaction mixture or by
conducting the reaction at reduced pressures. Preferably
the reaction between the boron reactant and the tertiary
128q)~0'~
amine will be carried out at temperatures ranging from
about 100C to about 250C and most preferably between
about 150C and 230C while blowing with nitrogen.
Although normally the amines will be liquid at room
temperature, in those instances where the amine reactant
is a solid or semi-solid, it will be necessary to heat the
amine to above its melting point in order to liquify it
prior to the addition of the boron-containing reactant
thereto. Those of ordinary skill in the art can readily
determine the melting point of the amine either from the
general literature or through a simple melting point
analysis.
Generally, the amine reactant alone will serve as the
solvent for the reaction mixture of the boron containing
reactant and amine reactant. However, if desired, an
inert normally liquid organic solvent can be used such as
mineral oil, naptha, benzene, toluene or xylene can be
used as the reaction media. Where the organo-borate
additive compound is to be added directly to a lubricating
oil, it is generally preferred to conduct the reaction
merely using the amine reactant as the sole solvent.
The borated fatty acid esters of glycerol are
prepared by borating a fatty acid ester of glycerol with
boric acid with removal of the water of reaction.
Preferably, there is sufficient boron present such that
each boron will react with from l.S to 2.5 hydroxyl groups
present in the reaction mixture.
The reaction may be carried out at a temperature in
the range of 60C to 135C, in the absence or presence of
any suitable organic solvent such as methanol, benzene,
xylenes, toluene, neutral oil and the like.
Fatty acid esters of glycerol can be prepared by a
variety of methods well known in the art. Many of these
esters, such as glycerol monooleate and glycerol
tallowate, are manufactured on a commercial scale. The
esters useful are oil-soluble and are preferably prepared
from C8 to C22 fatty acid or mixtures thereof such as are
-~ - 17 -
12~3~40~
found in natural products. The fatty acid may be
saturated or unsaturated. Certain compounds found in
acids from natural sources may include licanic acid which
contains one keto group. Most preferred C8 to C22 fatty
acids are those of the formula RCOOH wherein R is alkyl or
alkenyl.
The fatty acid monoester of glycerol is preferred,
however, mixtures of mono- and diesters may be used.
Preferably any mixture of mono- and diester contains at
least 40% of the monoester. Most preferably, mixtures of
mono- and diesters of glycerol contain from 40 to 60
percent by weight of the monoester. For example,
commercial glycerol monooleate contains a mixture of from
45% to 55% by weight monoester and from 55% to 45%
diester.
Preferred fatty acids are oleic, stearic, isostearic,
palmitic, myristic, palmitoleic, linoleic, lauric,
linolenic, and eleostearic, and the acids from the natural
products tallow, palm oil, olive oil, peanut oil, corn
oil, neat's foot oil and the like. A particularly
preferred acid is oleic acid. The borated fatty acid
esters are conveniently stabilized against hydrolysis by
reacting the esters with an alkyl or alkenyl mono- or
bis-succinimide.
The amount of the friction modifier employed in the
transmission fluids of the present invention is typically
from about 0.1% to about 5%, preferably from about 0.25%
to about 4%, and most preferably from about 0.5% to about
3.5% by weight of the total composition.
A sulfurized olefin is included in the present
invention as an extreme pressure agent. Extreme pressure
agents are materials which retain their character and
prevent metal to metal damage, e.g., contact, when gears
are engaged and meshed. The sulfurization of olefins is
generally known as is evidenced by United States Patent
4,191,659 as previously disclosed.
- 18
~28[)~0~
The sulfurized olefins which are useful in the
present invention are those materials formed from olefins
which been reacted with sulfur. Thus, an olefin is
defined as a compound having a double bond connecting two
aliphatic carbon atoms. In its broadest sense, the olefin
may be defined by the formula R1R2C=CR3R4, wherein each of
R , R , R3 and R is hydrogen or an organic radical. In
general, the R values in the above formula which are not
hydrogen may be satisfied by such groups as -C(R5)3,
-COOR , -CON(R )2' -COON(R )4, -COOM, -CN,
-C(R5)=C(R )2' -C(R5)=Y
-X, -YR or -Ar.
Each R5 is independently hydrogen, alkyl, alkenyl,
aryl, substituted alkyl, substituted alkenyl or
substituted aryl, with the proviso that any two R5 groups
can be alkylene or substituted alkylene whereby a ring of
up to about 12 carbon atoms is formed;
M is one equivalent of a metal cation (preferably
Group I or II, e.g., sodium, potassium, magnesium, barium,
calcium);
X is halogen (e.g., chloro, bromo, or iodo);
Y is oxygen or divalent sulfur; and
Ar is an aryl or substituted aryl radical of up to
about 12 carbon atoms.
Any two of R , R , R and R may also together form
an alkylene or substituted alkylene group; i.e., the
olefinic compound may be alicyclic.
The nature of the substituents in the substituted
moieties described above are not normally a critical
aspect of the invention and any such substituent is useful
so long as it is, or can be made compatible, with
lubricating environments and does not interfere under the
contemplated reaction conditions. Thus, substituted
compounds which are so unstable as to deleteriously
decompose under the reaction conditions employed are not
19 --
)40':~
contemplated. However, certain substituents such as keto
or aldehydo can desirably undergo sulfurization. The
selection of suitable substituents is within the skill of
the art or may be established through routine testing.
Typical of such substituents include any of the above-
listed moieties as well as hydroxy, amidine, amino,
sulfonyl, sulfinyl, sulfonate, nitro, phosphate,
phosphite, alkali metal mercapto and the like.
The olefinic compound is usually one in which each R
value which is not hydrogen is independently alkyl,
alkenyl or aryl, or (less often) a corresponding
substituted radical. Monoolefinic and diolefinic
compounds, particularly the former, are preferred, and
especially terminal monoolefinic hydrocarbons; that is,
those compounds in which R3 and R4 are hydrogen and R1 and
R2 are alkyl or aryl, especially alkyl (that is, the
olefin is aliphatic). Olefinic compounds having about 3
to 30 and especially about 3 to 18 (most often less than
9) carbon atoms are particularly desirable.
Isobutene, propylene and their oligomers such as
dimers, trimers and tetramers, and mixtures thereof are
especially preferred olefinic compounds. Of these
compounds, isobutylene and diisobutylene are particularly
desirable because of their availability and the
particularly desirable because of their availability ana
the particularly high sulfur-containing compositions which
can be prepared therefrom.
The sulfurization of such compounds is conducted as
is known in the art and thus no further discussion of the
sulfurized olefin component is given at this point.
The sulfurized olefins useful in the present
invention as extreme pressure agents are typically
utilized at from about 0.1% to about 5%, preferably from
about 0.2S% to about 4% and, most preferably from about
0.5% to about 3.5% by weight of the total composition.
- 20 -
1~8~)40~
Various sulfurized olefins which are useful in the
present invention are shown in Table I below:
TABLE
% sulfur
5Olefinic Molar Temp., in
Example compound ratiol C. product
(a) Isobutene; 1- 1:1:0.5 171 46.9
butene2
(b) l-Octene 1:1.5:0.5 171 34.3
(c) Isobutene; 1- 1:1:0.5 171 44.
octene3
(d) Diisobutene 1:1.5:0.5 171 41.
(e) C16-C18 a-olefin 1:1.5:0.5 171 20.6
(f) Cyclohexene 1:1:0.5 171 31.8
(g) Isobutene; 1- 1:1:0.5 171 39.5
hexene2
(h) Methyl oleate 1:1.5:0.5 171 16.5
(i) a-Methylstyrene 1:1:0.5 171 39.2
(j) Isobutene; 1:1:0.5 171 47.2
butadiene3
(k) Polyisobutene4 1:1.5:0.5 171 2.6
(l) Triisobutene 1:1.5:0.5 171
(m) l-Butene 1:1:0.5 138-171 49.5
(n) Isodecyl acrylate 1:0.5:0.5 171 13.1
(o) Diels-Alder 1:1.5:0.5 171 25.1
adduct of butadiene
and butyle acrylate
(p) 2-Butene6 1:1:0.5 171 48.9
(q) Turpentine 1:1.5:0.5 171 39.2
Olefinic compound(s):S:H2S.
1:1 molar ratio.
0.9:0.1 molar ratio.
Number average molecular weight of about 1000 a
determined by vapor pressure osmometry.
5No separation step.
6Cis and trans isomers.
128~)~0~
The synthetic lubricating oils useful herein include
hydrocarbon oils and halosubstituted hydrocarbon oils such
as polymerized and interpolymerized olefins (e.g.,
polybutylenes, polypropylenes, propylene-isobutylene
copolymers, chlorinated polybutylenes, etc.); poly(l-
hexenes), poly(l-octenes), poly(l-decenes), etc. and
mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes,
tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-
benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyls,
alkylated polyphenyls, etc.); alkylated diphenyl ethers
and alkylated diphenyl sulfides and the derivatives,
analogs and homologs thereof and the like.
Alkylene oxide polymers and interpolymers and deriva-
tives thereof where the terminal hydroxyl groups have been
modified by esterification, etherification, etc.,
constitute another class of known synthetic lubricating
oils that can be used. These are exemplified by the oils
prepared through polymerization of ethylene oxide or
propylene oxide, the alkyl and aryl ethers of these
polyoxyalkylene polymers (e.g., methylpolyisopropylene
glycol ether having an average molecular weight of about
1000, diphenyl ether of polyethylene glycol having a
molecular weight of about 500-1000, diethyl ether of
polypropylene glycol having a molecular weight of about
25 1000-lS00, etc.) or mono- and polycarboxylic esters
thereof, for example, the acetic acid esters, mixed C3-C8
fatty acid esters, or the C13Oxo acid diester of tetra-
ethylene glycol.
Another suitable class of synthetic lubricating oils
that can be used comprises the esters of dicarboxylic
acids (e.g., phthalic acid, succinic acid, alkyl succinic
acids, alkenyl succinic acids, maleic acid, azelaic acid,
suberic acid, sebacic acid, fumaric acid, adipic acid,
linoleic acid dimer, malonic acid, alkyl malonic acids,
alkenyl malonic acids, etc.) with a variety of alcohols
- 22 -
~2~3~40'~
(e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, ethylene glycol, diethylene glycol
monoether, propylene glycol, etc.). Specific examples of
these esters include dibutyl adipate, di(2-ethylhexyl)
sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate,
didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl
diester of linoleic acid dimer, the complex ester formed
by reacting one mole of sebacic acid with two moles of
tetraethylene glycol and two moles of 2-ethylhexanoic acid
and the like.
Esters useful as synthetic oils also include those
made from C5 to C12 monocarboxylic acids and polyols and
polyol ethers such as neopentyl glycol, trimethylol
propane, pentaerythritol, dipentaerythritol, tripent-
aerythritol, etc.
Silicon-based oils such as the polyalkyl-~ polyaryl-,
polyalkoxy- or polyaryloxy-siloxane oils and silicate oils
comprise another useful class of synthetic lubricants
(e.g., tetraethyl silicate, tetraisopropyl silicate,
tetra-(2-ethylhexyl)silicate, tetra-(4-methyl-hexyl)-
silicate, tetra-(p-tert-butylphenyl)silicate, hexyl-
(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes,
poly(methylphenyl)siloxanes, etc.). Other synthetic
lubricating oils include liquid esters of phosphorus-
containing acids (e.g., tricresyl phosphate, trioctvl
phosphate, diethyl ester of decane phosphonic acid, etc.),
polymeric tetrahydrofurans and the like.
Polyolefin oligomers are typically formed by the
polymerization reaction of alpha-olefins. Nonalpha-
olefins may be oligomerized to give a synthetic oil within
the present invention, however, the reactivity and
availability of alpha-olefins at low cost dictates their
selection as the source of the oligomer.
The polyolefin oligomer synthetic lubricating oils of
interest in the present invention include hydrocarbon oils
and halo-substituted hydrocarbon oils such as are obtained
- 23 -
1280~04
as the polymerized and interpolymerized olefins, e.g.,
oligomers, include the polybutylenes, polypropylenes,
propylene-isobutylene copolymers, chlorinated poly-
butylenes, poly(l-hexenes), poly(1-octenes), poly(1-
decenes)-, similar materials and mixtures thereof.
Typically, the oligomer is obtained from a monomer
containing from about 6 to 18 carbon atoms, preferably
from about 8 carbon atoms to about 12 carbon atoms. Most
preferably, the monomer used to form the oligomer is
decene, and preferably 1-decene. The nomenclature alpha-
olefin is a trivial name and the IUPAC nomenclature of a
1-ene compound may be considered to have the same meaning
within the present invention.
While it is not essential that the oligomer be formed
from an alpha-olefin, such is desirable. The reason for
forming the oligomer from an alpha-olefin is that
branching will naturally occur at the points where the
olefin monomers are joined together and any additional
branching within the backbone of the olefin can provide
too high a viscosity of the end oil. It is also desirable
that the polymer formed from the alpha olefin be
hydrogenated. The hydrogenation is conducted according to
known practices. By hydrogenating the polymer free
radical attack on the allyic carbons remaining after
polymerization is minimized.
The molecular weight of the oligomer is typically
averages from about 250 to about 1400, conveniently from
about 280 to about 1200 preferably from about 300 to about
1100 and most preferably about 340 to about 520. The
choice of molecular weight of the oligomer is largely
dependent upon whether a viscosity improver is included
within the formulation. That is, the polyolefin oligomer,
may require either a thickening or a thinning effect to
ensure that the proper lubricating viscosities are
maintained under extreme heat and cold conditions.
A further desirable synthetic lubricant is an
alkylated aromatic compound. The alkvlated aromatic
- - 24 -
1~8~40dS
compounds are particularly beneficial in improving the low
temperature flow characteristics. The alkylated aromatics
may be referred to, supra, under the discussion of the
alkaline earth metal salt. The alkylated aromatics are
the same base materials utilized to manufacture the
aromatic sulfonate.
The alkylated aromatic compound may be obtained in
mixture with the sulfonate due to incomplete sulfonation
of the alkylated aromatic. Of course, the alkylated
aromatic may be obtained directly. Preferably, the
aromatic nucleus of the alkylated aromatic compound is
benzene~ A particularly useful synthetic lubricant is a
mixture of the alpha olefin oligomer and the alkylated
aromatic. Typically, a mixture of the oligomer to the
alkylated aromatic will be at a weight ratio of about 8:1
to about 1:8.
The amount of the synthetic lubricant which is
employed in the present invention is typically from about
4% to about 98%, with intermediate ranges of about 7% to
about 96~, and about 5% to about 95%~ by weight of the
composition. The variability in the amount of the
synthetic lubricant utilized in the present invention is
largely because the synthetic lubricant may be obtained as
a separate material with components A through C inclusive
being utilized as a concentrate. ~hat is, components A
through C require more specialized processing condition~
than the formation of the synthetic lubricant and thus it
is often convenient to ship components A through C for
blending with the synthetic lubricant. Where a
concentrate is desired, components (A), (B) and (C) are
conveniently obtained at from 95% to 50% by weight of the
composition and the synthetic lubricant is obtained at 5%
to 50% by weight of the composition.
Several additional components are desirably added to
the manual transmission fluids of the present invention.
Viscosity improving materials as previously referred to
may be included in the compositions of the present
- 25 -
~28~4
invention. The viscosity index improvers typically
include polymerized and copolymerized alkyl methacrylates
and mixed esters of styrene-maleic anhydride interpolymers
reacted with nitrogen-containing compounds.
Polyisobutylene compounds are also typically used as
viscosity index improvers. The amount of viscosity
improver which may be typically added to the fully
formulated manual transmission fluid composition is about
1% to about 50%, preferably about 10% to about 25% bv
weight.
Zinc salts are also added to manual transmission
lubricants. Zinc salts are ordinarily utilized as extreme
pressure agents such as zinc dithiophosphates. The zinc
salts are added at levels measured by weight of the zinc
15 metal at from about 0.02% to about 0.2%, preferably from
about 0.04~ to about 0.15% by weight.
Mineral oil such as 100 neutral oil may be included
in the present invention. That is, it may be desirable as
the mineral oil is less expensive than the oligomer to
formulate the composition removing a portion of the
oligomer and replacing the same with the mineral oil.
Thus, when mineral oil is utilized in the composition of
the present invention, it may be present at from 0.1% to
about 75~, preferably from about 0.5~ to about 50% by
weight of the total composition.
Additional ingredients which may be included in the
manual transmission fluid of the present invention are
fatty acid amides which are useful as additional friction
modifiers, particularly for reducing the static
coefficient of friction. Further useful components herein
include seal swell agents such as sulfones and sulfolanes.
Suitable seal swell agents are disclosed in United States
Patent 4,029,587 to Koch issued June 14, 1977. A still
further useful component in the present invention is a
foam suppression agent such as a silicone oil. Any other
typical ingredient may be included herein such as pour
point depressants, dyes, odorants and the like.
- 26 -
128~40'~
The products of the present invention are obtained as
a light orange, nearly clear liquid. Typical prior art
manual transmission fluids will turn black after extended
useage and a visible inspection is thus not possible. An
advantage to the compositions of the present invention is
that the products may be visually examined for contamin-
ants. Such contaminants may indicate the failure of seals
or metal parts within the manual transmission. Thus a
particular utility of the products of the present
invention in addition to being highly effective in having
a high dynamic and a low static coefficient of friction is
that they may be visually examined for deterioration of
the transmission or contamination of the transmission
fluid. The products herein are also of relatively low
viscosity at temperatures of -25C and thus shift easily.
The products herein are primarily designed for manual
transmission fluids although they may be used, where
appropriate, for hydraulic fluids and other functional
fluids.
The following are suggested examples of the present
invention.
040~
EXAMPLE I
A manual transmission fluid is prepared by combining
the following ingredients:
56.5 parts of a poly alpha-olefin based on 1-decene
monomer.
parts of a polyisobutylene having an average
molecular weight (Mw) of approximately 1700.
15 parts of an alkylated benzene wherein the average
alkyl chain is approximately 24 carbon atoms.
1 part of a maleic anhydride-styrene copolymer
esterified as a pour point depressant.
lOOppm foam inhibitor which is a polydimethyl
siloxane.
1.0 part zinc dithiophosphate
0.75 part dioleylphosphite
l part sulfurized olefin based on a mixture of 35
parts C -1 alpha-olefin, 63% soya oil and 2% oleic
acid whel~e ~he mixture has a sulfur content of 10% by
weight
0.25 part fatty amide
0.3 part seal swell agent.
3.5 part magnesium alkyl benzene sulfonate
(overbased) wherein the alkyl contains about 24
carbon atoms on average.
The product herein has a high dynamic coefficient of
friction and a low static coefficient of friction. Cold
weather viscosity is such that shifting is easily
accomplished. The product is a light orange in color.
- 28 ~ ~8~0~
EXAMPLE II
A manual transmission fluid is prepared by combining
the following ingredients:
56.5 parts of a poly alpha-olefin based on 1-decene
monomer.
parts of a polyisobutylene having an average
molecular weight (Mw) of approximately 1700.
15 parts of an alkylated benzene wherein the average
alkyl chain is approximately 24 carbon atoms.
1 part of a maleic anhydride-styrene copolymer
esterified as a pour point depressant.
lOOppm foam inhibitor which is a polydimethyl
siloxane.
l.0 part zinc dithiophosphate
0.5 part borated fatty (Cl6) epoxide
1 part sulfurized olefin of Example I
0.25 part fatty amide
3.5 part magnesium alkyl benzene sulfonate
(overbased) wherein the alkyl contains about 24
carbon atoms on average.
The product herein has a high dynamic coefficient of
friction and a low static coefficient of friction. Cold
weather viscosity is such that shifting is easily
accomplished. The product is a light orange in color.
-~ - 29 -
121~ 0~
EXAMPLE III
A manual transmission fluid is prepared by combining
the following ingredients:
56.5 parts of a poly alpha-olefin based on l-decene
monomer.
parts of a polyisobutylene having an average
molecular weight (Mw) of approximately 1700.
15 parts of an alkylated benzene wherein the average
alkyl chain is approximately 24 carbon atoms.
1 part of a maleic anhydride-styrene copolymer
esterified as a pour point depressant.
lOOppm foam inhibitor which is a polydimethyl
siloxane.
1.0 part zinc dithiophosphate
0.5 part borated fatty (C16) epoxide
1 part sulfurized olefin based on Example I
0.25 part fatty amide
3.5 parts calcium sulfur coupled alkyl (C12) phenate
overbased to 200 total base number.
The product herein has a high dynamic coefficient of
friction and a low static coefficient of friction. Cold
weather viscosity is such that shifting is easily
accomplished. The product is a light orange in color.
- 30 -
0
EXAMPLE IV
A manual transmission fluid is prepared by combining
the following ingredients:
56.5 parts of a poly alpha-olefin based on l-decene
monomer.
parts of a polyisobutylene having an average
molecular weight (Mw) of approximately 1700.
15 parts of an alkylated benzene wherein the averase
alkyl chain is approximately 24 carbon atoms.
1 part of a maleic anhydride-styrene copolymer
esterified as a pour point depressant.
lOOppm foam inhibitor which is a polydimethyl
siloxane.
1.0 part zinc dithiophosphate
0.75 part dioleylphosphite
1 part sulfurized olefin based on Example I
0.25 part fatty amide
3.5 part calcium alkyl benzene sulfonate (overbased)
wherein the alkyl contains about 24 carbon atoms on
average.
The product herein has a high dynamic coefficient of
friction and a low static coefficient of friction. Cold
weather viscosity is such that shifting is easily
accomplished. The product is a light orange in color.
)40~
EXAMPLE V
A manual transmission fluid is prepared by combining
the following ingredients:
56.5 parts of a poly alpha-olefin based on l-decene
S monomer.
20 parts of a polymethyacrylate having an average
molecular weight (Mw) of approximately 1700.
15 parts of an alkylated benzene wherein the average
alkyl chain is approximately 24 carbon atoms.
1 part of a maleic anhydride-styrene copolymer
esterified as a pour point depressant.
lOOppm foam inhibitor which is a polydimethyl
siloxane.
1.0 part zinc dithiophosphate
0.75 part dioleylphosphite
1 part sulfurized olefin based on a mixture of 35
parts Cl -1 alpha-olefin, 63% soya oil and 2% oleic
acid whe~e ~he mixture has a sulfur content of 10% by
weight.
0.25 part fatty amide.
0.3 part seal swell agent.
3.5 part magnesium alkyl benzene sulfonate
(overbased) wherein the alkyl contains about 24
carbon atoms on average.
The product herein has a high dynamic coefficient of
friction and a low static coefficient of friction. Cold
weather viscosity is such that shifting is easily
accomplished. The product is a light orange in color.
