Note: Descriptions are shown in the official language in which they were submitted.
01 ~1--
METHOD FOR REDUCING BRAKE NOISE
IN OIL IMMERSED DISC BRAK~S
05
FIELD OF THE INVE~TION
This invention relates to lubricating oil com-
positions, particularly to lubricating oil compositions
useful as functi3nal fluids in systems requiring coupling,
hydraulic fluids and~or lubrication of relatively moving
parts. More particularlyl it is concerned with functional
fluids for use in the lubrication of heavy machinery,
particularly high~power-output tractors, and to the reduc-
tion of brake chatter therein.
DESCRIPTION OF THE PRIOR ART
The use of heavy machinery, such as a tractor,
has increased the demand for high-performance lubricating
compositions Modern trac~ors have many power-assisted
components, such as power s~eering and power brakes.
Power brakes are preferably of the disc ~ype since they
have greater braking capacity The pre~erred disc brakes
are the wet-t~pe brake, which are immersed in a lubricant
and are therefQre isolated from dirt and grime
Such brakes suffer from at least one problem,
namely, brake chatter or brake squawk, This phenomenon is
a very unpleasant noise that occurs upon appli~ation of
the brake. In the past, riction-modifying agerlts, such
as dioleylhydrogen phosphite, have been added to the brake
lubricating composition to reduce the chatter. Lubricat-
ing compositions containing this additive tend to sufferfrom very high wear rates, particu1arly at high
temperature.
A further complication in eliminating brake
chatter is the desire to use the sarne functional fluid~
35 not only for the brake lubrication, but also for lubrica-
tion of other tractor parts, such as the hydraulic and
mechanical power take-offs, the tractor transmission,
gears and bearings, and the like. The functional fluid
must act as a lubricant, a power transfer means, and as a
heat transfer medium. Obtainirlg a compounded fl-lid to
~J
~r~
~1 --2--
meet all of these needs wlthout brake chatter is
difficult.
05 U.S. Paten~ No. 3,151,077 teaches the use of
borated monoacylated trimethylol alkanes as motor fuel and
lubricating oil additives. The addltives are taught to
reduce the incidence of surface igni~ion in an lnternal
combust~on engine and to inhibit the build-up of car-
buretor deposits.
U.SI Patent No. 21795,548 discloses the use oflubricating oil compositions containing borated l,2-alkane
diols~ The oil compositions are used in the crankcase of
an internal combustion engine in order to reduce oxidation
lS of the oil and corrosion of the metal parts of the engine
SUMMARY OF THE INVENTION
It has now been found that oil soluble borated
1,2-alkane diols of the Formula l:
R - CH - CH~
O ~ ~0
OH
wherein R is alkyl containing 8 to 28 carbon atoms~ act as
appropriace friction-modifying agents, which, when added
to a lubricating oil, exhibit good anti-chatter
characteristics.
More speciflcally, this invention relates to a
method or reducing brake chatter between oilrimmersed
disc brakes by lubricating the contac'cing surfaces of said
brakes with a composition comprising a major amount of a
lubricating oil containing an effective amount to reduce
chatter of a borated 1,2-alkane diol of ~he Formula I.
The bora~ed alkane-1,2-diols of the Eormula I
useful in the presenr invention are those having from lO
to 30, preferably 10 to 20 carbon atoms. Single carbon
4~ number species ma~ be employed such as borated decane-1,2
~l -3-
diol, bora~ed octadecarle-1,2-dlol, borated eicosane-1,2
diol, borated tricontane-1,2-diol, and the like, but a
~5 blend of several carbon numbers is preferred. Typical
blends include the borated 1,2 diols of 10 to 30 (incl.)
carbon atom alkanes; the borated 1,2-diols of 12, 14l 16,
18 and 20 carbon atom alkanes; the borated 1,2-diols of 15
to 20 (incl.) carbon atom alkanes; ~he borated 1,2-diols
~ of 15 to 18 (incl~) carbon a~om alkanes; the bora-ted 1,2-
diols of 20 to 24 (incl.) carbon atom alkanes; ~he borated
1,2-diols of 24, 26 and 28 carbon akom alkanes, and the
like.
The borated long-chain 1/2-alkane diols are
lS prepared by borating a long-chain 1,2-alkane diol of the
formula.
R - CH - CH2
I I II
OH OH
wherein R is as defined above, with a stoichiometric
amount of boric acicl with removal of the water of reaction
by a7.eotropic distillation. The reaction is believed to
proceed according to the following scheme:
R - CH - CH2 -~ B(OH)3 solvent ~3 R - CH ~ CH2
~ l l
OH OH ~ \ ~o
OH
where R is alkyl containing 8 to 28 carbon atoms.
The reaction may be carried out at a tQmperature
in the range of 60C to 135C, in the presence of any
suitable organic solvent such as methanol, benzene,
x.ylenes, toluenel neutral oil and the like. If the
solvent does not form an azeotrope with water, enough of
an azeotropic forming agent is included to remove water
azeotropically.
~0
~9-~s~
The diols useful for this invention are either
commercially available or are readily prepared from the
S corresponding 1-olefin by methods well-known in the art.
For examplel the olefin i5 first reacted with peracid,
such as pero~yacetic acid or hydrogen peroxide plus formic
acid to form an alkane~1~2-epoxide which is readily
hydrolyzed under acid or base catalysis to the alkane-1,2-
diol, In another process, the olefin is first halogenated
to a 1,2~dihalo-alkane and subsequently hydrolyzed to an
alkane~l,2~diol by reaction first with sodium acetate and
then with sodium hydroxide.
1-Olefins are available from the thermal crack-
ing of waxes. This process produces 012fins of all carbon
numbersO l~-Olefins having an even number of carbon atoms
are prepared by the well-known ethylene "growth" reactionO
Olefins obtained by either of these processes are essen-
tially linear in structure with little or no branching.
Linear olefins are the preferred olefins for conversion
into alkane-1,2-diols.
The lubricating compositions used in the process
of this invention contain a major amount of a lubricating
oil and from about 0.1% to 5.0~ by weight of the borated
1,2-alkane diol of the Formula I, preferably from 005~ to
2~ by weight based on the weight of the total composition.
The optimum amount of a borated 1,2-alkane diol within
these ranges will vary slightly depending on the base oil
and other additives present in the oil.
Additive concentrates are a]so included within
the scope of this invention. In the concentrate additive
form, the borated 1~2-alkane diol is preserlt in a concen-
tration ranging from 5~ to 50% by weight~
The lubricating compositions are prepared by
admixing, using conventional techniques, the appropriate
amount of the desired borated 1,2-alkane diol with the
lubricating oil. When concentrates are being prepared,
the amount of lubricating oil is limited, but is suffi~
cient to dissolve the required amount of bora~ed 1,2-
4~ alkane diol. Gener;ll]y, the concentrate will have
Z
01 ~5~
sufficient borated l,2-alkane diol to permit subsequent
dilution with 1~ to l0 fold more lubricating oilO
~5 The lubricating oil, which may be employed in
the practice of this invention, includes a wide variety of
hydrocarbon oils derived from synthetic or natural sources,
such as naphthenic base~ paraffin base, and mixed base
oils as are obtained from the refining of crude oil.
Other lubrica~ing oils derived from shale oil, tar sands
or coal are also useful. The lubricating oils may be used
individually or in combinations wherever miscible. The
lubricating oils generally have a viscosity which ranges
from 50 to 5,000 SUS ~Saybolt Universal Seconds)~ and
usually from 100 to l,500 SUS at 100Fo The preferred
oils have an SAE rating in the range of 10 to 40 and are
paraffinic in structure
In some tractor systems in which the brake fluid
is kept in a separate sump, the hydrocarbon oil/borated
l~2-alkane diol composition of ~his invention is a suffi-
cient lubricant and can be used as such. Howev r/ in themore usual tractor systems in which there is a common sump
for all functional fluids, e.g., transmission lubricant,
hydraulic fluid, and the like, the lubricating oil is
compounded with a variety of additives. These additives
include anti-oxidants, detergents, dispersants, rus~ inhi
bitors, foam inhibitors, corrosion inhibitors, anti-wear
agents, viscosity index (VI) improvers, friction control
agents, elastomer swell agents, extreme pressure (EP)
agents, pour point depressants, and metal deactivators
All of these additives are well-known in the lubricating
oil art.
The preferred additives which may be added to
the lubricating oils to which the borated 1~2-alkane diols
of the Formula I are added/ are the oil soluble deter
gentsl such as the alkali or alkaline earth metal
hydrocarbyl sulfonates, or alkali or alkaline earth metal
phenates, or mixtures thereof, extreme pressure additives,
~0
~i -6-
such as the Group II metal salt dihydrocarbyl dithiophos-
phates and dispersants such as the alkenyl succinimides,
~5 or succinates or mixtures thereof
The alkali or alkaline earth metal hydrocarbyl
sulfonates may be either petroleum sulonate t synthetic-
ally alkylated aromatic sulfonates, or aliphatic sulfo-
nates such as those derived from polyisobutylene. One of
the more important functions of the sulfonates is to act
as a detergent and dispersant. These sulfonates are well-
known in the art. The hydrocarbyl group must have a suf~
ficient number of carbon atoms to render the sulfonate
molecule oil soluble Preferably, the hydrocarbyl portion
lS has at least 20 carbon atoms and may be aromatic or
aliphatic, but is usually alkylaromatic. Most preferred
for use are calcium, magnesium or barium sulfonates which
are aromatic in characterO
Certain sulfonates are typically prepared by
sulfonating a pe roleum fraction having aromatic groups,
usually mono- or dialkylbenzene groups~ and then forming
the metal salt of the sulfonlc acid material~ Other eed-
stocks used for preparing these ~ulfonates include syn-
thetically alkylated benzenes and aliphatic hydrocarbons
~5 prepared by polymerizing a mono or diolefin, for example~
a polyisobutenyl group prepared by polymerizing isobutene.
The metallic salts are formed directly or by metathesis
using well known procedures.
The sulfonates may be neutral or overbased
3~ having base numbers up to about 400 or more. Carbon
dioxide is the most commonly used material to produce the
basic or overbased sulfonates. Mixtures of neutral and
overbased sulonates may be used. The neutral sulfonates
are ordinarily used so as to provide from 5 to 25 milli-
moles of sulfonate per kilogram of the total composi-tion.
Preferably, the neutral sulfonates are present from 10 to
20 millimoles per kilogram of the total composition and
the overbased sulonates are present from 50 to 200 milli~
moles per kilogram of the total composition.
~1
The phenates for use in this invention are those
conven~ional products which are the alkali or a]kaline
~5 earth metal salts of alkylated phenols. One of the func
tions o ~he phenates is to act as a detergent and disper-
sant. The phenols may be mono- or polyalkylated~
The alkyl portion of the alkylphenate is present
to lend oil solubility to the phenate. The alkyl portion
can be obtained from naturally occurriny or synthetic
sources. Naturally occurring sources lnclude petroleum
hydrocarbons such as white oil and wax. Being derived
from petroleum, the hydrocarbon moiety is a mixture of
different hydrocarbyl groups, ~he specific composition of
which depends upon the particular oil stock which was used
as a startlng materialO Suitable synthetic sources
include various commercially available alkenes and alkane
derivatives which, when reacted with the phenol, yield an
alkylphenol. Suitable radicals obtained include butyl~
hexyl, octyl, decyl, dodecyl, hexadecyl~ eicosyl,
tricontyl, and the like~ Other suitable synthetic sources
of the alkyl radlcal include olefin polymers such as poly-
propylene, polybutylene, polyisobut~lene and the like J
The alkyl group can be straight-chained or
branch-chained, saturated or unsaturated (if unsaturatedy
preferably containing not more than 2 and generally not
more than 1 site of olefinic unsaturation). The alkyl
radicals will generally contain from 4 to 30 carbon atoms
Generally when the phenol is monoal]cyl~substituted, the
alkyl radical should contain at least 8 carbon atoms. The
phenate may be sulfurized if desired. It may be either
neutral or overbased and if overbased will have a base
number of up to 200 to 300 or more. Mixtures of neutral
and overbased phenates may be used.
The phenates are ordinarily present in the oil
to provide from 10 to 60 millimoles of phena~e per lcilo-
gram of the total composition. PreEerably, the neutral
phenates are present from 20 to 50 millimoles per lcilogram
of the total composltion and the overbased phenates are
present frorn 50 to 200 milllmoles per kilogram of the
01 _~_
total composition~ Preferred metals are calcium, magne~
sium, strontium or bariumO
OS The sulfurized alkaline earth metal alkyl-
phenates may also be used. These salts are obtained by a
variety of processes such as treating the neutralization
product of an alkaline earth metal base and an alkylphenol
with sulfur. Conveniently the sulur, in elemental form,
1~ is added to the neutralization product and reacted at
elevated temperatures to produce the sulfurized alkaline
earth metal alkylphenate~
If more alkaline earth metal base were added
during the neutralization reaction than was necessary to
neutralize the phenol, a basic sul~urized alkaline earth
metal alkylphenate is obtained. 5ee, for example7 the
process o Walker et al, U~S. Patent No. 2,680,096. Addi-
tional basicity can b~ obtained by adding carbon dioxide
~o the basic sulfurized alkaline earth metal alkylphenate.
2~ The excess alkaline earth metal base can be added subse=
quent to the sulfurization step but is conveniently added
at the same time as the alkaline earth me~aL base is added
to neutrallz~ the phenol.
Carbon dioxide is the most commonly used
material to produce the basic or "overbased" phenates~ A
process wherein basic sulfurized alkaline earth metal
alkylphenates are produced by adding carbon dioxide is
sho~n in ~anneman, U.S. Patent No. 3,178,368~
The Group II metal salts of dihydrocarbyl di-
thiophosphoric acids exhibit wear, antioxidan-t and thermal
stability properties. Group II metal sal~s of phosphoro-
dithioic acids have been described previously. See, for
example, U.S. Patent No. 3,390/080~ columns 6 and 71
wherein these compounds and their preparation are des-
cribed generally~ Suitabl~, the Group II metal salts Oethe dihydrocarbyl dithiophosphoric acids useful in the
lubricating oil composition o this invention contain from
about 4 to about 12 carbon atoms in each of the hydro
carbyl radicals and may be the same or different and may
4~ be aromatic, alkyl or cycLoalk~l. Preeerred hydrocarbyl
5~
~1
groups are alkyl groups containing from 4 to 8 carbon
atoms and are represented by butyl, isobutyl, sec.-butyl,
~5 hexyl, isohexyl, octyl, 2-ethylhexyl ?nd the like~ The
metals suitable for forming these salts include barium
calcium, strontium, zinc and cadmium~ of whlch zinc is
preferred.
Preferably, the Group II metal salt of a dihy-
l~ drocarbyl dithiophosphoric acid has the following formulaO
~ P
R30 S 2 M
wherein:
R2 and R3 each independently represent hydrocarbylradicals as described above, and
Ml represents a Group II metal ca~ion as described
2 above.
The dithiophosphoric salts are present in the
lubricating oil composition in an amount effective to
inhibit wear and oxidation of the lu~ricating oil. The
preferred amount ranges from about 3 to 30 millimoles of
dithiophosphoric sa]t per kilogram of the total composi-
tion. Most preferably the salt i5 present in an amount
ranging from about 15 to 20 millimoles per kilogram of the
tot~l lubricating oil composition.
The alkenyl succinimide or succinate or mixtures
thereof are present to, among other things, act as a dis-
persant and prevent formatlon of deposits. The alkenyl
succinimides and succinates are well-known in the art.
The alkenyl succinimides are the reaction product of a
polyolefin polymer-substituted succinic anhydride with an
amine, preerably a polyalkylene polyamine, and the
alkenyl succinates are the reaction product of a poly~
olefin polymer-substituted succinic anhydride with ~ono-
hydric and polyhydric alcohols, phenols and naphthols,
preferably a polyhydric alcohol containing at least thr2e
~0
hydroxy radicals. The polyolefin polymer-subs-tituted succini.c
anhydrides are obtained by reaction of a polyole:Ein polymer or
a derivative thereof with maleic anhyclride. The succinic
anhydride thus ob-tained is reacted with the amine or hydroxy
compound. The preparation of the alkenyl succinimides has
been described many times in the art. See, for example,
United States Patent Nos. 3,390,082, 3,219,666 and 3,172,892.
The preparation of the alkenyl succinates has also been
described in the art. See, for example, United States Patent
Nos. 3,381,022 and 3,522,179.
Particularly good results may be obtained with the
lubricating oil compositions of this invention when -the
alkenyl succinimide or succinate is a polyisobu-tene~
substituted succinic anhydride of a polyalkylene polyamine
or polyhydric alcohol, respectively.
The polylsobutene from which the polyisobutene-
substituted succinic anhydride is obtained by polymerizing
isobutene and can vary widely in its compositions. The
average number of carbon atoms can range from 30 or less -to
250 or more, with a resulting number average molecular weight
of about 400 or less to 3,000 or more. Preferably, the
average number of carbon atoms per polyisobutene molecule
will range from about 50 to about 100 with -the polyisobutenes
having a number average molecular weight of about 600 to
about 1,500. More preferably, the average number of carbon
atoms per polyisobutene molecule ranges from about 60 -to
about 90, and the number average molecular weight ranges from
about 800 to 1,300~ The polyisobutene is reacted with maleic
anhydride according to well-known procedures -to yield the
polyisobutene-substituted succinic anhydride.
In preparing che alkenyl succinimi.de, the subs-tituted
succinic anhydride is reacted wi-th a polyalkylene polyamine to
-lO-
~,
yield the correspondin~3 succinimi~e. Each a:Lkylene radical
of the polyalkylene polyamine usually has
-lOa-
0 1 ~
up to about 8 carbon atoms. The number of alkylene radi~
cals can range up to about 8. The alkylene radical is
0S exemplified by ethylene, propylene, butylene, trimethyl-
ene, te~ramethylene, pentamethylene, hexamethylene, octa-
methylene~ etc~ The number of amino groups yenerally, but
not necessarily, i5 one grea~er than the number of
alkylene radicals present in the amine~ i.e., if a poly-
alkylene polyamine contains 3 alkylene radicals, it will
usually contain 4 amino radicals. The number of aminoradicals ca~ range up to about 9. Preferably/ the alkyl
ene radical contains from ahout 2 to about 4 carbon atoms
and all amine groups are primary or secondary. In this
case~ the number of ~mine groups exceeds the number of
alkylene groups by 1. Preferably the polyalkylene
polyamine contains from 3 to 5 amine groups. Specific
examples of the polyalkylene polyamines include ethylene-
diamine, diethyler.etriamine, triethylenete~ramine, propyl-
enediamine, t-ripropylenetetramine, tetraethylenepentamine,
trimethylenediamine, pentaethylenehexamine, di-
(trimethylene)triamine/ tri(hexamethylene)tetramine~ etc.
Other amines suitable for preparing the alkenyl
succinimide useful in this invention include the cyclic
amines such as piperizine, morpholine and dipiperizines~
Preferably the alkenyl succinimides which may be
used in the compositions of this invention have the
following formula~
R~ fl-C
I ~ N~Alkylene-NtnH
CH2-C~ A
wherein-
a. Rl represents an alkenyl group, preferably a sub-
stantially saturated hydrocarbon prepared by polymerizing
aliphatic monoolefins. Preferably Rl is prepared from
~1 -12-
isobutene and has an average number oE carbon atoms and a
number average molecular weight as described above;
~5 b. the ~Alkylene" radical represents a substantially
hydrocarbyl group containing up to about 8 carbon a-toms
and preferably containing from about 2-4 carbon atoms as
described hereinabove;
c. A represents a hydrocarbyl group, an amine-sub-
stituted hydrocarbyl group, or hydrogen. The hydrocarbyl
group and the amine-substituted hydrocarbyl groups are
generally the alkyl and amino-substitu ed alkyl analogs of
the alkylene radicals described above~ Preferably
represents hydrogen;
d. n represents an integer of from about 1 to 10,
and preferably from about 3-5~
The alkenyl succinimide can be reacted with
boric acid or a similar boron-containing compound to form
borated dispersants having utility in this inven~ion. The
borated succinimides are intended to be included within
the scope of the term "alkenyl succinimide".
The alkenyl succinates are those of the above-
described succinic anhydride with hydroxy compounds which
may be aliphatic compounds such as monohydric and poly-
hydric alcohols or aromatic compounds such as phenols andnaphthols~ The aromatic hydroxy compounds from which the
~sters may be derived are illustrated by ~he following
specific examples: phenol, beta-naphthol, alpha-naphthol,
cresol, resorcinol, catehol, p,p' dihydroxybiphenyl,
3a 2-chlorophenol, 2,4~dibutylphenol/ propene tetramer-sub-
stituted phenol, didodecylphenol, 4,4'-methylene-bis-
phenol~ alpha-decyl-beta-naphthol, polyisobutene(molecular
weight of 1000)-substituted phenol, the condensation prod-
uct of heptylphenol with 0.5 mole of formaldehyde, the
condensaticn product of octylphenol with acetone,
di(hydroxyphenyl)oxide, di(hydroxyphenyl)sulfide,
di~hydroxyphenyl)disulfide, and ~-cyclohexylphenol.
Phenol and alkylated phenols having up to three alkyl sub~
stituents are preferred. Each of the alkyl subs~ituen~s
4~ may contain 100 or more carbon atoms.
01 -13~
The alcohols from which the esters may be
derived preferably contain up to about 40 aliphatic carbon
~S atomsO They may be monohydric alcohols such as methanol,
ethanol, isooctanol, dodecanol, cyclohexanol, cyclo-
pentanol, behenyl alcohol, hexatriacontanol, neoperltyl
alcohol~ isobutyl alcohol, benzyl alcohol, betaphenylethyl
alcoholl 2-methylcyclohexanol, beta-chloroethanol, mono-
methyl ether of ethylene glycol, monobutyl ether ofethylene glycol, monopropyl ether of die~hylene glycol,
monododecyl e~her of triethylene glycol, monooleate of
ethylene glycol, monostearate of diethylene glycol~ sec-
pentyl alcohol~ tert-butyl alcohol~ 5-bromo~dodecanol,
nitro~octadecanol and dioleate of glycerol. The poly-
hydric alcohols preferably contain from 2 to about 10
hydroxy radicals~ They are illustrated by, for example,
ethylene glycol/ diethylene glycol, triethylene glycol,
tetraethylene glycol, dipropylene glycol~ tripropylene
2~ glycol, dibutylene glycol, tributylene glycol~ and other
alkylene glycols in which the alkylene radical contains
rom 2 to about 8 carbon atoms. Other useful polyhydric
alcohols include glycerol, monooleate of glycerol,
monomethyl ether of glycerol~ pentraerythritol, 9,10-
dihydroxy stearic acid, methyl ester of 9,10-dihydroxy
stearic acid, 1,2-butanediol, 2,3-hexanediol, 2,4~hexane-
diol, pinacol, erythritoll arabitol, sorbitol, mannitol9
1,2-cyclohexanediol, and xylene glycol. Carbohydrates
such as sugars~ starches~ celluloses, etcO, likewise may
yield esters. The carbohydrates may be exemplified by a
glucose, fructose, sucrose, rhamnose~ mannose, glyceralde-
hyde, and galactose.
An especially preerred class of polyhycdric alco-
hols are those having at least three hydroxy radicals, some
of which have been esterified with a monocarboxylic acid
having from about 8 to about 30 carbon atoms such as octa-
noic acidl oleic acid~ stearic acid, linoleic acicl, dode
canoic acid, or tall oil acid. Examples of such partially
esteriied polyhydric alcohols are the monooleate of
sorbitol, disteara-te of sorbito], rnonoolea-te of glycerol,
monostearate of glycerol, di-dodecanoate oF ery-thri-tol.
The esters may also be derived from unsaturated
alcohols such as allyl alcohol, cinnamyl alcohol, propargyl
alcohol, 1-cyclohexene-3-ol, an oleyl alcohol. S-till other
classes of the alcohols capable of yielding the esters of
this invention comprises the ether-alcohols and amino-
alcohols including, for example, the oxy-alkylene-, oxy-
arylene-, amino-alkylene-, and amino-arylene-substituted
alcohols having one or more oxy-alkylene, amino-alkylene or
amino-arylene oxy-arylene radicals. They are exemplified by
Cellosolve, carbitol, phenoxy-ethanol, heptylphenyl-(oxy-
propylene)6-H, octyl-(oxyethylene)3o~H, phenyl(oxyoctylene)2-H,
mono(heptylphenyl-oxypropylene)-substituted glycerol,
polytstyrene oxide), am:ino-ethanol, 3-amino ethyl-pentanol,
di(hydroxyethyl)amine, p-aminophenol, tri(hydroxypropyl)amine,
N-hydroxyethyl ethylene diamine, N~N,N',N'-tetrahydroxy-
trimethylene diamine, and the like. For -the most part, the
ether-alcohols having up to about 150 oxy-alkylene radicals
in which the alkylene radical contains from 1 to about 8
carbon atoms are preferred.
The esters may be di-esters of succinic acids or
acidic esters, i.e., partially esterified succinic acids,
as well as partially esterified polyhydric alcohols or phenols,
i.e., esters having free alcoholic or phenolic hydroxyl
radicals. Mixtures of the above-illustra-ted es-ters likewise
are contemplated within the scope of the invention.
The alkeny] succinates can be reacted with boric
acid or a similar boron-containiny compound -to form borated
dispersants having utility in this invention. Such borated
succinates are described in United S-ta-tes Patent No. 3,533,9~5.
The borated succinates are intended to be included within the
5~Z
scope of the term "alkenyl succinate."
The alkenyl succinimide and succinates are present
in the lubricatlng oil compositions in an amoun-t
-l~a-
I
~1 --1 S--
effective to act as a dispersant and prevent the deposit
of contaminan~s formed in ~he oil. The amount of alkenyl
05 succinimide a~d succinates can range from about 0.5 per-
cent to about 20 percent weight of the total lubricatiny
oil composition. Preferably the amount of alkenyl suc-
cinimide or succinate which may be present in the lubri~
cating oil composition ranges Erom about 2 to about 5
percent by weight of the total composition.
The finished lubricating oil may be single or
multigradeO Multigrade lubricating oils are prepared by
adding viscosity index (VI~ lmprovers~ Typical viscosity
index improvers are polyalkyl methacrylates, ethylene pro-
i5 pylene copolymers~ styrene diene copolymers and the likerSo c~lled decorated VI improvers having both viscosity
index and dispersant properties are also sui~able for use
in the formulations of this invention~
The following examples are ofered to specific-
ally illustrate the invention. These examples and illus~
trations are not to be construed in any way as limiting
the scope of the invention.
Example 1
A five-liter reaction flask was charged with
1050 grams (4 moles~ of C15~1~ alkane 1,2-diol; 272 grams
(4.4 moles) of boric acid and 1500 grams of xyleneO The
stirred reaction mixture was hea~ed under reElux for 90
hours. At the end of this time 191 mls of water was col-
lectedO The reaction mixture was cooled, filtered and the
solvent was removed in vacuo to afford 1158 grams of pro~
duct containing 6.3~ boron.
Example 2
The compositions of this invention were tested
in a laboratory test. The test was carried out on an S~E
No. 2 friction machine modified by adding a moderate-speed
hydraulic mo~or drive. The te.st specimen was a sandwich
of one General ~etals Powder Co. 1500 mix sintered bronze
plate between t~o steel spacer plates mounted in the above
apparatus. The test fluid, about 300 grams in quantity,
4~ was then charged to the test-oil sump. The hydr~ulic
01 -16-
drive rotatecl th~ test specimen~ at 100 rpm. ~ piston-
like brake was applied at an apply pre~sure o-f 75 psig.
05 The SAE No. 2 load cell measured the braking torque and an
electric tachometer measured rpm. ~n x-y plot~er was used
to produce a trace of torque versus rpm as the hydraulic
drive was slowly adjusted to decrease the speed to 0 rpm.
The brake chakter performance of a fluid is related to the
~ slope of th~ riction vs~ velocity curve. The slop~ of
the curve is found by measuring the slope of a line drawn
through the 50 rpm point on the trace and ~he highest
point on the trace below 50 rpm. As the slope o-f this
curve becomes increasingly negativel th~ brake chatter
noise becomes progressively louder. This tendency corre-
lates with full scale tractor brake noise tests.
Th~ above described test was run on threemineral oil based tractor hydraulic fluids. The results
for these three fluids are shown in Table I~ Composition
A was a base without a friction modifier and composi~ion B
contains in addition 1% borated alkanediol of Example lo
Composition C is a commercial tractor hydraulic fluid. As
shown in Table I, the addition of borated 1,2-alkanediol
~Fluid B) to the base fluid (Fluid A) increased the slope
25 indicating it i~ effective in reducing brake chatterO Also
shown in Table 1 is the 510pe ob~ained with a commercial
tractor hydraulic fluido
3~
~0
~3~5~Z
01 -17-
TABLE I
Efect of Borated 1,2~Alkanediol
~5 Upon Laboratory Brake Chatter Simulation
Slope of Friction
Formulation Velocity Curve
A - base oil -.0131
B - base oil + 1% by ~0086
weight Borated 1,2-
alkanediol of Example 1
C - Commercial Formulation~0143
2S
3~
~0
