Note: Descriptions are shown in the official language in which they were submitted.
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F-2799-L
GREASE COMPOSIT IOI I
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This invention relates to grease compositions comprising
oil, hydroxy-containing soap thickener and borated alkoxylated
alcohols and optionally, phosphorus and sulfur moieties.
Borated alkoxylated alcohols have been used in commercial
lubricant formulations to provide improvements in lubricating
properties. This is known from U.S. Patent 3,711,411, which
describes hydraulic fluids containing such products.
It is known also that borated esters and related borates
can be used in other areas. for example, U.S. Patent 3,740,358
describes a phenol-aldehyde foamable compositions containing boron
compounds, for example a material formed by reacting boric acid or
boric oxide with an aliphatic hydroxyl-containing compound.
However, no effort has been made hitherto to employ borated
alkoxylated alcohols in combination with a metal hydroxy-containing
soap thickeners in grease compositions.
In accordance with the invention, there is provided a
grease composition containing a major proportion of a grease and a
minor amount of a compound prepared by reacting an alkoxylated
2~ alcohol or mixtures of such alcohols having the formula
RO(R O)xH
in which R is a hydrocarbyl group containing from 7 to 30 carbon
atoms, preferably 9 to 18 carbon atoms, R is a hydrocarbylene
group containing from 2 to 4 carbon atoms and x has a value from 1
to 10, with a boron compound selected from boric acid, boric oxide,
metaborate and alkyl borate of the formula
(R O)yB(OH)z
in which y is 1, 2 or 3, z is 0, 1 or 2, the sum of y and z is 3,
and the or each R2 is an alkyl group containing from 1 to 6 carbon
F-2799-L -- 2 --
atoms, characterized in that the grease contains a thickener
comprising a hydroxy-containing soap. Such compositions have been
found to possess substantially higher dropping points compared to
compositions thickened with other thickeners. The presence of
phosphorus and sulfur moieties provides an even higher dropping
point.
Preferably the alkoxylated alcohol is overborated, that is
to say the borated product contains more than a stoichiometric
amount of boron.
The hydrocarbyl group can be a cyclic or a straight or
branched chain hydrocarbon group and can contain one or more
unsaturated sites. The hydrocarbyl group is preferably an alkyl
group, for example octyl, nonyl, decyl, dodecyl, isotridecyl,
tetradecyl, pentadecyl, heptadecyl and octadecyl. Other possible
hydrocarbyl groups include propylcyclohexyl, butylcyclohexyl, oleyl,
stearyl, isostearyl, coco and mixtures thereof as well as similar
groups. It may be preferable to use alkoxylated alcohols that have
been prepared using a mixture of alcohols. The hydrocarbyl group
can also be an aryl group, in which the aryl nucleus has 6 to 14
carbon atoms. The hydrocarbylene group is preferably an alkylene
group, for example ethylene, propylene and butylene.
The alkoxylated alcohols are themselves well known, as are
methods for preparing them. In general, they can be made by
reacting, in the presence of a catalyst, an alcohol with an epoxide
such as ethylene oxide or propylene oxide.
Boration of the alkoxylated alcohols is accomplished with
the boron compound described above. The reaction can be carried out
in the presence of a solvent and, in general, any relatively
non-polar, unreactive solvent can be used, including benzene,
tuluene~ xylene and 1,4-dioxane. Mixtures of such solvents can also
be used. Reaction temperatures of from about 90 to about 280C can
be used. Reaction times can be from 1 to 24 hours or more. Up to a
stoichiometric amount of boric acid or alkyl borate is preferably
used to yield a product containing from about 0.1 to about 10~ of
boron. At least 5 to 10% of the available hydroxyl groups on the
alcohol can be borated to derive substantial beneficial effect.
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Conversely, a stoichiometric excess of boric acid (more than an
equivalent amount of borating agent compared to alcohol hydroxyl
groups) can also be used resulting in a product containing an even
greater amount of boron.
The alkoxylated alcohols can also be borated with an alkyl
borate such as mono-, di- or trimethyl borate, mono-, di- or
triethyl borate, mono-, di- or tripropyl borate, mono-, di- or
tributyl borate, mono-, di- or triaryl borate or mono-, di- or
trihexyl borate, often in the presence of boric acid.
Preferred reaction temperatures for boration with boric
acid are from about 110 to about 200C and with the borate f~om
about 160 to about 240C. The temperature chosen will depend for
the most part on the particular reactants and on whether or not a
solvent is used. In carrying out this reaction, it is preferable
that quantities of reactants are chosen such that the molar ratio of
alkoxylated alcohol to boron compound is from about 6:1 to about
1:6, preferably from about 3-1 to about 2:1. As stated above, the
alkoxylated alcohol can be reacted with an excess of the borating
species to form a borate ester containing from about 0.1% by weight
of boron to as much as 10% or more of boron.
While atmospheric pressure is generally preferred, the
reaction can be carried out under a pressure of up to 500 kPa.
A particular class of thickening agents is used to make the
grease compositions of the invention. The thickening agents are
those containing at least a portion of alkali metal or alkaline
earth metal or amine soaps of hydroxyl-containing fatty acids, fatty
glycerides and fatty esters having from 12 to about 30 carbon atoms
per molecule. The metals are typified by sodium, lithium, calcium
and barium with lithium being the preferred metal. Preferred acids
and fatty materials are 12-hydroxystearic acid and glycerides and
esters containing 12-hydroxystearates, 14-hydroxystearic acid,
16-hydroxystearic acid and 6-hydroxystearic acid.
F-2799-L -- 4 --
These thickeners need not constitute the total amount of
thickeners in the grease compositions. Significant benefit can be
attained using as little as about 15% by weight of these thickeners,
based on the total thickeners. A complementary amount, that is up
to about 85% by weight, of a wide variety of other thickening agents
can be used in the grease compositions of the invention. Included
among the other useful thickening agents are alkali metal and
alkaline earth metal soaps of methyl-12-hydroxystearate, diesters of
C4 to C12 dicarboxylic acids and tall oil fatty acids. Other
alkali or alkaline earth metal fatty acids containing from 12 to 30
carbon atoms and no free hydroxyl groups may be used. These include
soaps of s-tearic and oleic acids.
Other thickening agents include salt and salt-soap
complexes as calcium stearate-acetate (U.S. Patent 29197,26~),
barium stearate acetate (U.S. Patent 2,564,561), calcium,
stearate-caprylate-acetate complexes (U.S. Patent 2,999,065),
calcium caprylate-acetate (U.S. Patent 2,999,066), and calcium salts
and soaps of low-, intermediate- and high-molecular weight acids and
of nut oil acids. These thickening agents can be produced in open
kettles, pressurized vessels or continuous manufacturing units. All
of these production methods are commonly used for greases and have
the necessary supporting equipment to process the grease during and
after manufacture of the thickener.
Another group of thickening agents comprises substituted
ureas, phthalocyamines, indanthrene, pigments such as perylimides,
pyromellitdiimides, and ammeline, as well as certain hydrophobic
clays. These thickening agents can be prepared from clays which are
initially hydrophilic in character, but which have been converted
into a hydrophobic condition by the introduction of long-chain
hydrocarbon radicals into the surface of the clay particles prior to
their use as a component of a grease composition, for example by
being subjected to a preliminary treatment with an organic cationic
surface active agent, such as an onium compound. Typical onium
compounds are tetraalkylammonium chlorides, such as dimethyl
dioctadecyl ammonium chloridel dimethyl dibenzyl ammonium chloride
and mixtures thereof.
F-2799-L __ 5 __
An optional component of the grease compositions are
phosphorus and sulfur moieties. Both of these can be present in the
same molecule, such as in a metal or non-metal phosphorodithioate of
the formula
- ~ R )2 ~Z ~ M
in which R is a hydrocarbyl group containing 3 to 18 carbon
atoms, M is a metal or non-metal, n is the valence of M and each Z
is oxygen or sulfur with at least one Z being sulfur.
In this compound, R3 is preferably an alkyl group and may
be a propyl, butyl~ pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl
or octadecyl group, but also includes those derived from
isopropanol, butanol, isobutanol, sec-butanol, 4-methyl-2-pentanol,
2-ethylhexanol, oleyl alcohol, and mixtures thereof. Further
included are alkaryl groups such as butylphenyl, octylphenyl,
nonylphenyl and dodecylphenyl groups.
The metals covered by M include those in Groups IA, IB,
IIA, IB, IIa, VIB and VIII of the Periodic Table. Some that may be
mentioned are lithium, sodium, calcium, barium, zinc, cadmium,
silver, molybdenum and gold. Non-metallic ions include organic
groups derived from vinyl esters such as vinyl acetate, vinyl ethers
such as butyl vinyl ether and epoxides such as propylene oxide and
1,2-epoxydodecane. Non-metallic ions also include compounds derived
from hydrocarbylamines such as alkylamines, tertiaryalkylamines,
alkyldiamines or arylamines, as well as those derived from
oleylamine, N-oleyl-1,3-propylenediamine, imidazolines and
oxazolines.
The phosphorus and sulfur moieties can also be supplied
from the combination of two or more separate compounds, such as the
combination of (1) a dihydrocarbyl phosphite having 2 to 10 carbon
atoms in each hydrocarbyl 9roup or mixtures of phosphites and (2) a
sulfide such as sulfurized isobutylene, dibenzyl disulfide,
sulfurized terpenes and sulfurized jojoba oil. The phosphites
~L~ 3~
F-2799-L - 6 --
embrace the dibutyl, dihexyl, dioctyl, didecyl and similar
phosphites. Hydrocarbyl phosphate esters containing 4 to 20 carbon
atoms in each hydrocarbyl group, can also be used. These include
esters such as tributyl phosphate, tridecyl phosphate, tricresyl
phosphate and mixtures thereof. Mono- and dihydrocarbyl e.sters are
also useful.
In accordance with the invention, the total thickener will
contain at least about 15% by weight of a metal or non-metal
hydroxy-containing soap and the grease will contain from about 3~ to
about ~0% by weight of total thickener based on the grease
composition.
The grease composition also contains from about O.Ol~ to
about 10% by weight, preferably from about 0.1% to about 2%, of a
borated alkoxylated alcohol which has been prepared by reacting an
alkoxylated alcohol with preferably at least an equimolar amount of
boron compound.
The composition may also contain from 0.01% to about 10% by
weight, preferably from 0.2% to 2% by weight of phosphorus- and
sulfur-containing compounds or a mixture of two or more compounds
which together supply the phosphorus and sulfur moieties. If
separate compounds are used, an amount of the mixture equivalent to
the required concentration is used to supply desired amounts of
phosphorus and sulfur.
It has been found that grease compositions according to the
invention containing both the hydroxy-containing thickeners and the
borated alkoxylated alcohols, have dropping points consistently and
unexpectedly higher than those of greases derived from the same
grease vehicles and the same borated alkoxylated alcohols, but with
different thickeners, for example non-hydroxy-containing thickeners.
In general, the borated alkoxylated alcohols and the
phosphorus and sulfur moieties may be employed in any amount which
is effective for imparting the desired degree of -Friction reduction,
antiwear activity, antioxidant activity, high temperature stability
or antirust activity. In many applications, however, the borated
F-2799-L _ 7 __
alkoxylated alcohol and the phosphorus- and/or sulfur-
containing compound(s) are effectively employed in combined amounts
of from about 0.02% to about 20% by weight, and preferably from
about 0.2% to about 4% by weight, based on the total composition.
The grease compositions of the invention can be made from
either mineral oil or synthetic oil, or mixtures thereof. In
general, mineral oils, both paraffinic, naphthenic and mixtures
thereof, may be of any suitable lubricating viscosity range, as for
example, from about 45 SSU at 38C to about 6000 SSU at ~8~C, and
preferably from about 50 to about 250 SSU at 99C. These oils may
have viscosity indexes ranging to about lOO or higher. Viscosity
indexes from about 70 to about 95 are preferred. The average
molecular weights of these oils may range from about 250 to about
800. In making the grease, the lubricating oil from which it is
prepared is generally employed in an amount sufficient to balance
the total grease composition, after accounting for the desired
quantity of the thickening agent and other additive components.
When synthetic oils are used in preference to mineral oils,
various materials may be utilized. Typical synthetic vehicles
include polyisobutylene, polybutenes, hydrogenated polydecenes,
polypropylene glycol, polyethylene glycol, trimethylol propane
esters, neopentyl and pentaerythritol esters, di(2-ethylhexyl)
sebacate, di(2-ethylhexyl) adipate, dibutyl phthalate,
fluorocarbons, silicate esters, silanes, esters of phosphorus-
containing acids, liquid ureas, ferrocene derivatives, hydrogenated
synthetic oils, chain-type polyphenyls, siloxanes and silicones
(polysiloxanes), alkyl-substituted diphenyl ethers typified by a
butyl-substituted bis(p-phenoxy phenyl) ether, phenoxy
phenylethers. Other additives providing antirust, antioxidant
antiwear/EP, anticorrosion, and other desired properties can be used
with the greases of this invention.
The grease compositions according to the invention possess
the advantages of increased dropping point and improved grease
consistency properties and exhibit antirust characteristics and
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F-2799-L
potential antifatigue, antiwear and antioxidant benefits unavail-
able in any known grease. The grease compositions of the invention
have the additional advantage that they can be manufactured simply
by mixing additive quantities of the alkoxylated alcohol borates to
the fully formed soap grease after completion of saponification.
The following Examples illustrated the invention.
EXAMPLE 1
BORATED ALCOHOL ETHOXYLATE
1759 of commercial C12 to C15 alkanol triethoxylate
having an average molecular weight of 3~8, containing approximately
3.0 ethylene oxide groups per molecule and having a hydroxyl number
of 166, was charged to a 500 ml glass reactor equipped with
agitator, Dean-Stark tube and slow nitrogen purge of vapor space.
Approximately 13g of boric acid and about 509 of toluene were added
and the reaction mixture was heated to 160C and maintained for a
period of 6 hours until azeotropic distillation of water ceased.
Approximately 1209 of water was collected. Solvent was removed by
vacuum distillation and the product was filtered through
diatomaceous earth to yield a clear, light-colored, oil-soluble
fluid.
EXAMPLE 2
BORATED ALCOHOL ETHOXYLATE
Approximately 2749 of commercial Cg to Cll alcohol
ethoxylate containing approximately 2.6 moles of ethylene oxide per
molecule, having a molecular weight of approximately 274 and a
hydroxyl number of 205, was charged to a 1000 ml reactor equipped as
described in Example 1. Approximately 229 of boric acid and about
509 of toluene solvent were added. The reaction mixture was heated
to 195C and maintained for a period of 4 hours until azeotropic
distillation of water ceased. The toluene was removed by vacuum
distillation and the product was filtered over diatomaceous earth to
yield a clear, liqht-colored, oil-soluble liquid.
~Lr3~1 a~
F-2799-L __ g __
EXAMPLE 3
A lithium hydroxystearate grease thickener was prepared by
saponification of a mixture containing 12-hydroxystearic acid (8% by
weight) and the glyceride thereof (9% by weight) with lithium
hydroxide in a mineral oil vehicle at about 177~C in a closed
vessel. After depressuring and dehydrating the thickener in an open
kettle7 sufficient mineral oil was added to reduce the thickener
content to about 9.0%. After cooling to about 99C, a typical
grease additive package, consisting of an amine antioxidant,
phenolic antioxidant, 1.5% zinc dithiophosphate derived from mixed
C3 secondary and C6 primary alcohols, sulfur-containing metal
deactivator and nitrogen containing antirust additives, was added.
EXAMPLE 4
Two percent by weight of the reaction product of Example 1
was added at 110 to 115C, with vigorous stirring, to the base
grease of Example 3.
EXAMPLE 5
Two percent by weight of the reaction product of Example 2
was added at 110 to 115C, with vigorous stirring, to the base
grease of Example 3.
The base grease oF Example 3 and the compositions of
Examples 4 and 5 were tested for dropping point characteristics in
accordance with ASTM D22650 The results are summarized in the Table
below. For comparison, the dropping points of the following
compositions were determined also.
EXAMPLE 6
A base grease similar to that of Example 3 but thickened
with the lithium soap of a 50/50 by weight mixture of stearic and
palmitic acids.
F-27g9-L -- 1.0 --
EXAMPLE 7
A 50/50 by weight mixture of the base grease of Example 3
and the base grease of Example 6.
EXAMPLE 8
The base grease of Example 6 plus 2% by weight of the
borated ethoxylate of Example 1.
TABLE
PRODUCT OF EXAMPLE DROPPING POINT, C
3 202
4 237
305
6 209
7 190
8 207
