U.S. patent application number 15/772843 was filed with the patent office on 2018-11-01 for low viscosity gear lubricants.
The applicant listed for this patent is The Lubrizol Corporation. Invention is credited to William R.S. Barton, Gareth Brown, Suzanne Patterson.
Application Number | 20180312775 15/772843 |
Document ID | / |
Family ID | 57256455 |
Filed Date | 2018-11-01 |
United States Patent
Application |
20180312775 |
Kind Code |
A1 |
Patterson; Suzanne ; et
al. |
November 1, 2018 |
LOW VISCOSITY GEAR LUBRICANTS
Abstract
A lubricant composition of 40 to 95% of an oil having a
kinematic viscosity at 100.degree. C. of 3 to 7.5; 0.3 to 2% of an
amine salt of a phosphorus compound obtained by reacting phosphorus
pentasulfide with one or more alcohols having 4 to about 13, or 4
to 8, or 6, carbon atoms, with an alkylene oxide, and further with
phosphorus pentoxide, and salting the resulting material with one
or more amines having 2 to 20 or 12 to 24 carbon atoms; and an
active-sulfur containing agent in an amount to provide 0.5 to 7%
sulfur to the composition provides good wear protection to gears at
a relatively low viscosity of the composition.
Inventors: |
Patterson; Suzanne; (Seven
Hills, OH) ; Barton; William R.S.; (Belper, GB)
; Brown; Gareth; (Belper, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
The Lubrizol Corporation |
Wickliffe |
OH |
US |
|
|
Family ID: |
57256455 |
Appl. No.: |
15/772843 |
Filed: |
May 11, 2017 |
PCT Filed: |
May 11, 2017 |
PCT NO: |
PCT/US2016/059009 |
371 Date: |
May 2, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62251886 |
Nov 6, 2015 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C10N 2040/04 20130101;
C10M 2203/1025 20130101; C10M 2205/0285 20130101; C10M 2209/084
20130101; C10M 2223/047 20130101; C10M 2203/024 20130101; C10N
2030/43 20200501; C10M 135/04 20130101; C10M 169/04 20130101; C10M
2219/022 20130101; C10N 2040/02 20130101; C10N 2030/42 20200501;
C10N 2030/06 20130101; C10N 2060/14 20130101; C10M 2223/049
20130101; C10M 137/105 20130101; C10M 2203/1006 20130101; C10N
2030/02 20130101; C10M 105/04 20130101; C10M 2223/043 20130101;
C10N 2020/02 20130101; C10M 101/02 20130101; C10M 2209/086
20130101; C10M 2203/1025 20130101; C10N 2020/02 20130101; C10M
2203/1025 20130101; C10N 2020/02 20130101 |
International
Class: |
C10M 137/10 20060101
C10M137/10; C10M 101/02 20060101 C10M101/02; C10M 105/04 20060101
C10M105/04; C10M 135/04 20060101 C10M135/04 |
Claims
1. A lubricant composition comprising: (a) about 40 to about 95
percent by weight, or about 58 to about 80 percent by weight, of an
oil having a kinematic viscosity at 100.degree. C. by ASTM D445 of
about 3 to about 7.5, or about 3.6 to about 6, or about 3.5 to
about 5 mm.sup.2/s; (b) about 0.3 to about 2 percent by weight of
an amine salt of a phosphorus compound, or mixtures thereof,
obtained by reacting phosphorus pentasulfide with one or more
alcohols having 4 to about 13, or 4 to 8, or 6, carbon atoms, with
an alkylene oxide, and further with phosphorus pentoxide, and
salting the resulting material with one or more amines having 2 to
20 or 12 to 24 carbon atoms; and (c) a sulfurized olefin in an
amount to provide about 0.5 to about 7, or about 0.5 to about 1.5,
or about 1.5 to about 2, or about 3 to about 5, or about 2 to about
3, percent by weight sulfur to the composition; wherein said
composition has a kinematic viscosity at 100.degree. C. by ASTM
D445 of up to about 7.5 mm.sup.2/s.
2. The lubricant composition of claim 1 wherein the oil comprises a
polyalpha olefin having a kinematic viscosity at 100.degree. C. of
about 3 to about 7.5.
3. The lubricant composition of claim 1 wherein the oil comprises
an API Group III oil or a Group III+ oil.
4. The lubricant composition of claim 1 wherein the alkylene oxide
comprises 1,2-propylene oxide.
5. The lubricant composition of claim 1 wherein the alcohol has 6
carbon atoms.
6. The lubricant composition of claim 1 wherein the alcohol is
4-methylpentan-2-ol.
7. The lubricant composition of claim 1 having a phosphorus content
of or about 0.02 to about 0.20 weight percent phosphorus supplied
by the material of component (b).
8. The lubricant composition of claim 1 wherein the total
phosphorus content of the lubricant is about 0.08 to about 0.30
weight percent.
9. The lubricant composition of claim 1 further comprising an
overbased alkaline earth metal detergent in an amount to provide 1
to about 500 50 parts by million by weight alkaline earth
metal.
10. The lubricant composition of claim 1 being substantially free
from alkaline earth metal detergent.
11. The lubricant composition of claim 1 further comprising 5 to
about 30 percent by weight of a polymeric viscosity index
modifier.
12. A composition prepared by admixing the components of claim
1.
13. A method of lubricating a gear or a bearing, comprising
supplying thereto the lubricant composition of claim 1.
14. The method of claim 13 comprising lubricating a gear wherein
the gear is located in an axle assembly.
15. The method of claim 13 comprising lubricating a gear wherein
the gear is a hypoid gear.
16. The method of claim 13 wherein the lubricant composition is
employed in a lubricated axle assembly characterized by a .lamda.
value of less than 2.0, or 1.1 to 1.5, where .lamda. is defined as
the ratio of elastohydrodynamic film thickness of the lubricant to
the composite surface roughness of the gear surface.
Description
BACKGROUND
[0001] The disclosed technology relates to lubricants, especially
for gears or bearings, having a relatively low viscosity yet having
good antiwear performance by including in the lubricant a certain
amine salt of a phosphorus compound (or mixtures thereof).
[0002] Moving mechanical parts generally need to be lubricated.
Among surfaces or parts requiring lubrication are gears or
bearings, such as those that may be found in machinery or vehicles
such as in drivelines of vehicles (e.g., transmissions, gear boxes,
axles, differentials). An axle assembly may typically comprise one
or more gears and one or more bearings. In recent years the
lubrication and transportation industry have been moving toward
requiring gear oils of lower viscosity in order to provide improved
efficiency and fuel economy, for instance, due to reduced fluid
drag and energy loss. Lubricants of reduced viscosity, however,
tend to provide reduced lubricant film thickness between the
lubricated parts, and such systems thus become increasingly
dependent on boundary film protection, that is, chemical protection
of the surfaces provided by additive chemistry within the
lubricant, as distinct from the lubrication provided by the bulk of
the lubricant.
[0003] Film thickness may be described in terms of .lamda. ratio,
which is defined as the ratio of fluid film thickness to the
composite surface roughness of the surfaces being lubricated
(r.sub.1.sup.2+r.sub.2.sup.2).sup.1/2. The .lamda. ratio will
depend on the particular surfaces involved, the pressure applied
between the surfaces, and the viscosity of the lubricant, less
viscous lubricants tending to provide systems having a lower
.lamda.. It is often considered that when .lamda. is 3 or greater,
full-film, or thick film, or hydrodynamic, lubrication will
prevail. When .lamda. is between 1.2 and 3, the lubrication is
often referred to as mixed or thin film, and when .lamda. is less
than 1.2, boundary lubrication will prevail. That is, in the case
of boundary lubrication, over a certain portion of the lubricated
surface there may be direct physical contact between the surfaces
(or between the chemical coatings on the surfaces) with little or
no bulk lubricant separating the surfaces in those areas. It is for
lubricating conditions where .lamda. is 2 or less, 1.8 or less, or
1.5 or less, or 1.2 or less, that lubricating challenges become
more severe.
[0004] The wheels of an on-highway and/or off-highway vehicle can
be driven by a final drive axle unit that splits the torque
received from the input shaft between the wheels by means of a gear
set inside a gear housing of the final drive unit. The gears in the
final drive can be of the type including but not limited to spiral
bevel, hypoid, spur and helical or combination thereof. In one
example the gear arrangement can be a differential gear
arrangement. These gears require lubrication. Among the functions
of the gear lubricant are to provide adequate protection against
wear, scuffing, and micropitting and to provide for seal, rubber,
and composite material capability, while providing acceptable
oxidation stability and cleanliness during the service life of the
gear equipment. Therefore, there is need for a gear lubricating
composition having a relatively low viscosity while providing at
least one of wear protection and seal, rubber and composite
material capability.
[0005] U.S. Pat. No. 3,197,405, Le Suer, Jul. 27, 1965, discloses
phosphorus- and nitrogen-containing compositions useful as
additives in lubricating compositions. They may be prepared by
reacting a hydroxyl-substituted triester of a phosphorothioic acid
with an inorganic phosphorus reagent and neutralizing with a
hydrocarbon- or hydroxy-substituted hydrocarbon amine having about
4 to about 30 carbon atoms.
[0006] U.S. Pat. No. 8,865,633, MacPherson et al., Oct. 21, 2014
(earlier published as US 2013/0053288, Feb. 28, 2013) discloses
gear oil compositions including a major amount of a base oil having
a lubricating viscosity, a polysulfide extreme pressure agent, and
a reaction product of an acylated copolymer and a polyamine. An
antiwear agent may be present which may include, among others, an
organic ester of phosphoric acid, phosphorous acid, or an amine
salt thereof. The base oil is about 55 weight percent to less than
100 weight percent bright stock base oil. In an example, the gear
oil formulation had a viscosity grade of 80W-90.
[0007] The lubricating composition of the invention is suitable for
lubricants in a variety of mechanical devices, including
automobiles, trucks, and other equipment such as a manual
transmission, an automatic transmission, an automated manual
transmission, a continuously variable transmission, a dual clutch
transmission, a farm tractor transmission, a transaxle, a heavy
duty power-shift transmission, and wet brakes) as well as final
drive axles gearing systems and gears such as an automotive gear
and a farm tractor gear.
[0008] The disclosed technology solves the problem of providing
wear protection for gears which are lubricated with a relatively
low viscosity lubricant, and/or under a regime of .lamda..ltoreq.2,
by including in the lubricant an amine salt of a phosphorus
compound or mixtures thereof, as described in greater detail
herein.
SUMMARY
[0009] The disclosed technology provides a lubricant composition
comprising: (a) an oil having a kinematic viscosity at 100.degree.
C. by ASTM D445 of 3 to 7.5 or 3.6 to 6 or 3.5 to 5 mm.sup.2/s; (b)
0.3 to 2 percent by weight of an amine salt of a phosphorus
compound, or mixtures thereof, obtained by reacting phosphorus
pentasulfide with one or more alcohols having 4 to 13, or 4 to 8,
or 6, carbon atoms, with an alkylene oxide, and further with
phosphorus pentoxide, and salting the resulting material with one
or more amines having 2 to 20 or 12 to 24 carbon atoms; and (c) a
sulfurized olefin in an amount to provide about 0.5 to about 7, or
about 0.5 to about 1.5, or about 1.5 to about 2, or about 3 to
about 5, or about 2 to about 3, percent by weight sulfur to the
composition; wherein said composition has a kinematic viscosity at
100.degree. C. by ASTM D445 of up to 7.5, or 3.5 to 7.0, or 4 to
6.5, or 4 to 6 mm.sup.2/s.
[0010] The disclosed technology also provides a method of
lubricating a gear comprising supplying thereto the lubricant
composition described herein.
DETAILED DESCRIPTION
[0011] Various preferred features and embodiments will be described
below by way of non-limiting illustration.
[0012] The lubricant composition of the disclosed technology
comprises as one component, an oil of lubricating viscosity. Such
oils include natural and synthetic oils, oil derived from
hydrocracking, hydrogenation, and hydrofinishing, unrefined,
refined, and re-refined oils and mixtures thereof. Unrefined oils
are those obtained directly from a natural or synthetic source
generally without (or with little) further purification treatment.
Refined oils are similar to the unrefined oils except they have
been further treated in one or more purification steps to improve
one or more properties. Purification techniques are known in the
art and include solvent extraction, secondary distillation, acid or
base extraction, filtration, percolation and the like. Re-refined
oils are also known as reclaimed or reprocessed oils, and are
obtained by processes similar to those used to obtain refined oils
and often are additionally processed by techniques directed to
removal of spent additives and oil breakdown products.
[0013] Natural oils useful in making the inventive lubricants
include animal oils, vegetable oils (e.g., castor oil), mineral
lubricating oils such as liquid petroleum oils and solvent-treated
or acid-treated mineral lubricating oils of the paraffinic,
naphthenic or mixed paraffinic-naphthenic types and oils derived
from coal or shale or mixtures thereof.
[0014] Synthetic lubricating oils are useful and include
hydrocarbon oils such as polymerized and interpolymerized olefins
(e.g., polybutylenes, polypropylenes, propyleneisobutylene
copolymers); poly(l-hexenes), poly(l-octenes), poly(l-decenes), and
mixtures thereof; alkyl-benzenes (e.g. dodecylbenzenes,
tetradecylbenzenes, dinonyl benzenes, di-(2-ethylhexyl)-benzenes);
polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls);
diphenyl alkanes, alkylated diphenyl alkanes, alkylated diphenyl
ethers and alkylated diphenyl sulfides and the derivatives, analogs
and homologs thereof or mixtures thereof. Other synthetic
lubricating oils include polyol esters (such as Priolube.RTM.3970),
diesters, liquid esters of phosphorus-containing acids (e.g.,
tricresyl phosphate, trioctyl phosphate, and the diethyl ester of
decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic
oils may be produced by Fischer-Tropsch reactions and typically may
be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one
embodiment oils may be prepared by a Fischer-Tropsch gas-to-liquid
synthetic procedure as well as other gas-to-liquid oils.
[0015] Oils of lubricating viscosity may also be defined as
specified in the American Petroleum Institute (API) Base Oil
Interchangeability Guidelines (2011). The five base oil groups are
as follows: Group I (sulfur content >0.03 wt %, and/or <90 wt
% saturates, viscosity index 80 to less than 120); Group II (sulfur
content <0.03 wt %, and >90 wt % saturates, viscosity index
80 to less than 120); Group III (sulfur content <0.03 wt %, and
>90 wt % saturates, viscosity index .gtoreq.120); Group IV (all
polyalphaolefins (PAOs)); and Group V (all others not included in
Groups I, II, III, or IV). The oil of lubricating viscosity may
also be an API Group II+ base oil, which term refers to a Group II
base oil having a viscosity index greater than or equal to 110 and
less than 120, as described in SAE publication "Design Practice:
Passenger Car Automatic Transmissions", fourth Edition, AE-29,
2012, page 12-9, as well as in U.S. Pat. No. 8,216,448, column 1
line 57.
[0016] The oil of lubricating viscosity may be an API Group IV oil,
or mixtures thereof, i.e., a polyalphaolefin. The polyalphaolefin
may be prepared by metallocene catalyzed processes or from a
non-metallocene process. The oil of lubricating viscosity may
comprise an API Group I, Group II, Group III, Group IV, Group V oil
or mixtures thereof. Often the oil of lubricating viscosity is an
API Group I, Group II, Group II+, Group III, Group IV oil or
mixtures thereof. Alternatively the oil of lubricating viscosity is
often an API Group II, Group II+, Group III or Group IV oil or
mixtures thereof. Alternatively the oil of lubricating viscosity is
often an API Group II, Group II+, Group III oil or mixtures
thereof. In one embodiment, the oil of lubricating viscosity
comprises a polyalphaolefin. In one embodiment, the oil of
lubricating viscosity comprises a Group III oil or a Group III+ oil
(where Group III+ is a subset of Group III oils, having a higher
viscosity index such as .gtoreq.130). In one embodiment the poly
alpha olefin has a kinetic viscosity at 100.degree. C. of 3 to 7.5
(ASTM D445).
[0017] The oil of lubricating viscosity, as used in the disclosed
technology, will have a kinematic viscosity at 100.degree. C.
("KV_100") as determined by ASTM D445 of 3 to 7.5 mm.sup.2/s or
alternatively 3.3 to 6.5, or 3.6 to 6, or 3.5 to 5, mm.sup.2/s.
This viscosity value or range will be the viscosity of the entire
oil of lubricating viscosity component, whether it be an oil from a
single source and a single grade or a mixture of oils, but does not
include any contribution to viscosity of any additives such as
viscosity modifiers. In one embodiment the presence of small
amounts of diluent oil which may be conventionally provided along
with some of the additive components to be described later is not
included in the determination of the KV_100; alternatively, if
desired, the contribution of such diluent oils may be included. In
either event, the KV_100 of the oil (base oil) component is less
than about 7.5 mm.sup.2/s, which is a relatively low value for a
lubricant designed for use as a gear lubricant.
[0018] The KV_100 of the base oil, above, is one contributor to the
KV_100 of the finished lubricant containing the additional
components and additives described herein. Presence of additional
components may result in an increase in the KV_100 of the finished
lubricant, particularly if those components, such as polymeric
components, themselves have a relatively higher KV_100. The overall
KV_100 of the lubricant composition may be up to 8.5 or to 8.0 or
to 7.5, such as 3.5 to 7.0 or 4 to 6.5, or 4 to 6 mm.sup.2/s.
[0019] The amount of the oil of lubricating viscosity present is
typically the balance remaining after subtracting from 100 weight
percent the sum of the amount of the additives as described herein.
Typical amounts include 40 to 95 percent by weight, or 45 to 90, or
50 to 80, or 55 to 75, or 58 to 70, or 60 to 65 percent by
weight.
[0020] The lubricating composition may be in the form of a
concentrate and/or a fully formulated lubricant. If the lubricating
composition of the invention is in the form of a concentrate (which
may be combined with additional oil to form, in whole or in part, a
finished lubricant), the ratio of the of components of the
invention to the oil of lubricating viscosity and/or to diluent oil
include the ranges of 1:99 to 99:1 by weight, or 80:20 to 10:90 by
weight.
[0021] Another component of the lubricant is an amine salt of a
phosphorus acid ester. This material can serve as one or more of an
extreme pressure agent or a wear preventing agent. The amine salt
of a phosphorus acid ester includes phosphoric acid esters and
salts thereof; dialkyldithiophosphoric acid esters and salts
thereof; phosphites; and phosphorus-containing carboxylic esters,
ethers, and amides; and mixtures thereof. In one embodiment the
phosphorus compound comprises a sulfur atom in the molecule. In one
embodiment the amine salt of the phosphorus compound is ashless,
i.e., metal-free (prior to being mixed with other components).
[0022] The amine salt of the phosphorus acid ester may comprise any
of a variety of chemical structures. In particular, a variety of
structures are possible when the phosphorus acid ester compound
contains one or more sulfur atoms, that is, when the
phosphorus-containing acid is a thiophosphorus acid ester. The
thiophosphorus acid esters may be mono- or dithiophosphorus acid
esters. Thiophosphorus acid esters are also sometimes referred to
as thiophosphoric acids. A thiophosphorus acid ester may be
prepared by reacting a sulfur and phosphorus compound with an
alcohol. Suitable phosphorus compound include phosphorus sulfides
such as phosphorus pentasulfide. Suitable alcohols include those
containing 4 to 13 carbon atoms, or 4 to 8, or 5 to 7, or 6 carbon
atoms, including primary or secondary alcohols such as butyl,
isobutyl, amyl, s-amyl, 2-ethylhexyl, hexyl, cyclohexyl, octyl,
decyl and dodecyl alcohols and isomers thereof, as well as any of a
variety of commercial alcohol mixtures having similar numbers of
carbon atoms, e.g., 8 to 10. In one embodiment the alcohol has 6
carbon atoms; in one embodiment the alcohol comprises or is
4-methylpentan-2-ol.
[0023] In one embodiment, the thiophosphorus acid ester is a
monothiophosphoric acid ester or a monothiophosphate.
Monothiophosphates may be prepared by the reaction of a sulfur
source with a dihydrocarbyl phosphite. The sulfur source may, for
instance, be elemental sulfur, or an organosufide, such as a sulfur
coupled olefin or a sulfur coupled dithiophosphate. The preparation
of monothiophosphates is disclosed in U.S. Pat. No. 4,755,311 and
PCT Publication WO 87/07638, which describe monothiophosphates,
sulfur sources, and the process for making monothiophosphates.
Monothiophosphates may also be formed in the lubricant blend by
adding a dihydrocarbyl phosphite to a lubricating composition
containing a sulfur source, such as a sulfurized olefin. The
phosphite may react with the sulfur source under blending
conditions (i.e., temperatures from 30.degree. C. to 100.degree. C.
or higher) to form the monothiophosphate salt with an amine which
is present in the blend.
[0024] In certain embodiments, the phosphorus-containing acid is a
dithiophosphoric acid or phosphorodithioic acid. The
dithiophosphoric acid may be represented by the formula
(RO).sub.2PSSH wherein each R is independently a hydrocarbyl group
containing 4 to 13 carbon atoms, such as those derived from the
alcohol listed above. Examples of R include isobutyl, n-butyl,
sec-butyl, the various amyl, n-hexyl, methylisobutyl carbinyl,
heptyl, 2-ethylhexyl, isooctyl, nonyl, behenyl, decyl, dodecyl, and
tridecyl groups. Illustrative lower alkylphenyl R groups include
butylphenyl, amylphenyl, and heptylphenyl. Examples of mixtures of
R groups include 1-butyl and 1-octyl; 1-pentyl and 2-ethyl-1-hexyl;
isobutyl and n-hexyl; isobutyl and isoamyl; 2-propyl and
2-methyl-4-pentyl; isopropyl and sec-butyl; and isopropyl, and
isooctyl.
[0025] The dithiophosphoric acid is further reacted with an epoxide
and this reaction product further reacted with a phosphorus
pentoxide. The epoxide is generally an aliphatic epoxide or a
styrene oxide. Examples of useful epoxides include ethylene oxide,
propylene oxide, butene oxide, octene oxide, dodecene oxide, and
styrene oxide. The epoxides may be aliphatic epoxides having from 2
to 12, or 3 to 6, or 3 or 4 carbon atoms. In one embodiment the
alkylene oxide comprises 1,2-propylene oxide. The dithiophosphoric
acids, epoxides, inorganic phosphorus reagents, and methods of
reacting the same are described in U.S. Pat. Nos. 3,197,405 and
3,544,465.
[0026] The following Examples P-1 and P-2 exemplify the preparation
of useful phosphorus acid esters.
Example P-1
[0027] Phosphorus pentoxide (about 64 grams) is added at about
58.degree. C. over a period of about 45 minutes to about 514 grams
of hydroxypropyl O,O-di(4-methyl-2-pentyl)phosphorodithioate
(prepared by reacting di(4-methyl-2-pentyl)-phosphorodithioic acid
with about 1.3 moles of propylene oxide at about 25.degree. C.).
The mixture is heated at about 75.degree. C. for about 2.5 hours,
mixed with a diatomaceous earth and filtered at about 70.degree. C.
The filtrate contains about 11.8% by weight phosphorus, about 15.2%
by weight sulfur, and an acid number of 87 (bromophenol blue).
Example P-2
[0028] A mixture of about 667 grams of phosphorus pentoxide and the
reaction product of about 3514 grams of diisopropyl
phosphorodithioic acid with about 986 grams of propylene oxide at
about 50.degree. C. is heated at about 85.degree. C. for about 3
hours and filtered. The filtrate contains about 15.3% by weight
phosphorus, about 19.6% by weight sulfur, and an acid number of 126
(bromophenol blue).
[0029] Acidic phosphoric acid esters may be reacted with ammonia or
an amine, including polyamines, to form an ammonium salt. The salts
may be formed separately and then the salt of the phosphorus acid
ester may be added to the lubricating composition. The amines which
may be suitable for use as the amine salt include primary amines,
secondary amines, tertiary amines, and mixtures thereof. The amines
include those with at least one hydrocarbyl group, or, in certain
embodiments, two or three hydrocarbyl groups. The hydrocarbyl
groups may typically contain 2 to 30 carbon atoms, or in other
embodiments 8 to 26 or 10 to 20 or 13 to 19 carbon atoms.
[0030] Primary amines include ethylamine, propylamine, butylamine,
2-ethylhexylamine, octylamine, and dodecylamine, as well as such
fatty amines as n-octylamine, ndecylamine, n-dodecylamine,
n-tetradecylamine, n-hexadecylamine, n-octadecylamine, and
oleylamine. Other useful fatty amines include commercially
available fatty amines such as "Armeen.RTM." amines (products
available from Akzo Chemicals, Chicago, Ill.), such as Armeen C,
Armeen O, Armeen O L, Armeen T, Armeen H T, Armeen S and Armeen S
D, wherein the letter designation relates to the fatty group, such
as coco, oleyl, tallow, or stearyl groups.
[0031] Examples of suitable secondary amines include dimethylamine,
diethylamine, dipropylamine, dibutylamine, diamylamine,
dihexylamine, diheptylamine, methylethylamine, ethylbutylamine and
ethylamylamine. The secondary amines may be cyclic amines such as
piperidine, piperazine, and morpholine.
[0032] The amine may also be a tertiary-aliphatic primary amine.
The aliphatic group in this case may be an alkyl group containing 2
to 30, or 6 to 26, or 8 to 24 carbon atoms. Tertiary alkyl amines
include monoamines such as tert-butylamine, tert-hexylamine,
1-methyl-1-amino-cyclohexane, tert-octylamine, tert-decylamine,
tertdodecylamine, tert-tetradecylamine, tert-hexadecylamine,
tert-octadecylamine, tert-tetracosanylamine, and
tert-octacosanylamine.
[0033] Mixtures of amines may also be used in the invention. In one
embodiment a useful mixture of amines is "Primene.RTM. 81R" and
"Primene.RTM. JMT." Primene.RTM. 81R and Primene.RTM. JMT (both
produced and sold by Rohm & Haas) are mixtures of C11 to C14
tertiary alkyl primary amines and C18 to C22 tertiary alkyl primary
amines respectively.
[0034] Suitable hydrocarbyl amine salts of dialkyldithiophosphoric
acid esters of the invention may be represented by the formula:
##STR00001##
wherein R.sup.26 and R.sup.27 are independently hydrogen or
hydrocarbyl groups such as alkyl groups; for the phosphorus acid
ester, at least one of R.sup.26 and R.sup.27 will be hydrocarbyl.
R.sup.26 and R.sup.27 may contain 3 or 4 to 30, or 8 to 25, or 10
to 20, or 13 to 19 carbon atoms. R.sup.23, R.sup.24, and R.sup.25
can be independently hydrogen or hydrocarbyl groups, such as alkyl
branched or linear alkyl chains with 1 to 30, or 4 to 24, or 6 to
20, or 10 to 16 carbon atoms. These R.sup.23, R.sup.24, and
R.sup.25 groups can be branched or linear groups, and in certain
embodiments at least one, or alternatively two of R.sup.23,
R.sup.24, and R.sup.25 are hydrogen. Examples of alkyl groups
suitable for R.sup.23, R.sup.24, and R.sup.25 include butyl,
sec-butyl, isobutyl, tert-butyl, pentyl, n-hexyl, sec-hexyl,
n-octyl, 2-ethylhexyl, decyl, undecyl, dodecyl, tridecyl,
tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl,
octadecenyl, nonodecyl, eicosyl groups and mixtures thereof.
[0035] In one embodiment the hydrocarbyl amine salt of an
alkylthiophosphoric acid ester is the reaction product of a
C.sub.14 to C.sub.18 alkylated phosphoric acid with Primene 81R.TM.
(produced and sold by Rohm & Haas) which is a mixture of
C.sub.11 to C.sub.14 tertiary alkyl primary amines. Other amines
which may be used include alkyl alkanol amines, dialkanolamines,
trialkanolamines such as triethanolamines as well as borated amines
as described hereinbelow.
[0036] The amine salt of as used as this component in the present
invention may thus comprise a C.sub.8 to C.sub.20 alkylamine salt
of a mono- or di-alkyl phosphate ester, or mixtures thereof. It
will be understood by the skilled person that the amine salt of the
thiophosphrus acid ester will typically comprises a mixture of
various individual chemical species. Reference herein to "an amine
salt of a phosphorus compound," used in the description of
component (b) herein will be understood by the skilled person to
encompass mixtures of such compounds as may be prepared by the
described syntheses.
[0037] The amount of the amine salt of the thiophosphorus acid
ester in the lubricant can be 0.3 to 2 weight percent, or 0.4 to
1.9, or 0.5 to 1.8, or 0.7 to 1.7 weight percent. The amounts will
be proportionally higher in a concentrate. The amount of said amine
salt may also be an amount to contribute 0.03 to 0.2 weight percent
phosphorus to the lubricant composition, or alternatively 0.08 to
0.17, or 0.11 to 0.17 weight percent.
[0038] One or more additional phosphorus compounds may also
optionally be present, beside the amine salt of the thiophosphorus
acid described above. They may provide a measure of additional
antiwear performance, or they may be present for other functional
reasons. Some of these may be amine salts of phosphorus esters, but
without the sulfur component of the above-described chemistry.
Examples include amine salts of dialkylphosphates such as a
branched C8 amine salt of di-isooctyl phosphate; phosphites such as
dibutyl phosphite, di 16- or 18-carbon alkyl- or
alkylene-phosphites (that is, in which the long carbon chains may
optionally contain unsaturation); an amine salt of phosphoric acid
oleyl esters; and phospholipids such as lecithins, e.g., borated
lecithins. The total amount of phosphorus in the lubricant
composition from all sources may be 0.03 to 0.30 weight percent, or
0.03 to 0.25, or 0.03 to 0.21, or 0.05 to 0.21, or 0.08 to 0.30, or
0.08 to 0.25, or 0.08 to 0.21, or 0.10 to 0.20, or 0.12 to 0.18
weight percent.
[0039] Component (c) is the sulfurized olefin, which may also be
considered to be an active sulfur containing compound. A definition
of active sulfur is that the compound meets the definition of
sulfur reactive with copper powder at a temperature of 149.degree.
C. The test method for determining active sulfur is determined in
the STANDARD TEST METHOD FOR ACTIVE SULFUR IN CUTTING FLUIDS
Designation: D 1662-69 (Reapproved 1979) as set forth by the
American Society for Testing and Materials (ASTM).
[0040] A wide variety of sulfurized olefins can be utilized and
these compounds may generally be represented by the formula
RS.sub.xR.sub.1 wherein S represents sulfur, x is a whole number
having a value of from 1 to about 10, and R and R.sub.1 may be the
same or different organic groups derived from olefins. The organic
groups may be hydrocarbon groups or substituted hydrocarbon groups
containing alkyl, aryl, aralkyl, alkaryl, alkanoate, thiazole,
imidazole, phosphorothionate, or beta-ketoalkyl groups. The
substantially hydrocarbon groups may contain other substituents
such as halogen, amino, hydroxyl, mercapto, alkoxy, aryloxy, thio,
nitro, sulfonic acid, carboxylic acid, or carboxylic acid
ester.
[0041] Specific examples of types of sulfurized olefins include
alkyl or alkenyl sulfides and polysulfides, sulfurized carboxylic
acid ester olefins, sulfurized ester olefins, sulfurized olefinic
oil, and mixtures thereof. The preparation of such sulfurized
olefins is described in the art.
[0042] The sulfurized olefin compounds utilized in the present
invention can be alkyl sulfides such as dicetyl sulfide, diparaffin
wax sulfide and polysulfide, or cracked wax oleum sulfides. One
method of preparing the alkyl sulfides includes the condensation of
a chlorinated hydrocarbon with an inorganic sulfide whereby the
chlorine atom from each of two molecules is displaced, and the free
valence from each molecule is joined to a divalent sulfur atom.
Generally, the reaction is conducted in the presence of elemental
sulfur.
[0043] Examples of dialkenyl sulfides are described in U.S. Pat.
No. 2,446,072. These sulfides can be prepared by reacting an
olefinic hydrocarbon containing from 3 to 12 carbon atoms with
elemental sulfur in the presence of zinc or a similar metal
generally in the form of an acid salt. Examples of sulfides of this
type include 6,6'-dithiobis(5-methyl-4-nonene), 2-butenyl
monosulfide and disulfide (the diisobutyl sulfides), and
2-methyl-2-butenyl monosulfide and disulfide. Certain sulfurized
isobutylenes may contain 40 to 45 weight percent sulfur.
[0044] The sulfurized olefins include materials prepared by the
reaction of an olefin (such as those containing 2 to 6 carbon
atoms) or a lower molecular weight polyolefin derived therefrom,
with a sulfur-containing compound such as sulfur, sulfur
monochloride, sulfur dichloride, hydrogen sulfide, and combinations
thereof.
[0045] The olefin is usually one in which each R is independently
alkyl, alkenyl or aryl, or a corresponding substituted group.
Monoolefinic and diolefinic compounds, particularly the former, may
be used, such as terminal monoolefinic hydrocarbons. Olefinic
compounds having 3 to 30, or 3 to 16, or 9 or fewer, or 8 carbon
atoms may be used.
[0046] Ethylene, isobutene, propylene, and oligomers thereof are
especially preferred olefinic compounds. Of these compounds,
isobutylene and diisobutylene are particularly desirable because of
their availability and the particularly high sulfur-containing
compositions which can be prepared therefrom.
[0047] Another class of sulfurized olefins includes sulfurized
aliphatic esters of an olefinic mono- or dicarboxylic acid. For
example, aliphatic alcohols of from 1 to 30 carbon atoms can be
used to esterify monocarboxylic acids such as acrylic acid,
methacrylic acid, or 2,4-pentadienoic acid or fumaric acid, maleic
acid, or muconic acid Sulfurization of these olefinic esters is
conducted with elemental sulfur, sulfur monochloride and/or sulfur
dichloride.
[0048] Still another class of sulfurized olefin compounds which can
be utilized in the compositions of the invention are diester
sulfides characterized by the general formula
ROOC(CH.sub.2).sub.x--S.sub.y--(CH.sub.2).sub.xCOOR wherein each x
is independently 2 to 5; y is 1 to 6, such as 1 to about 3; and
each R is independently an alkyl group having 4 to 20 carbon atoms.
The R group may be a straight chain or branched chain group that is
large enough to maintain the solubility of the compositions of the
invention in oil. Typical diesters include the butyl, amyl, hexyl,
heptyl, octyl, nonyl, decyl, tridecyl, myristyl, pentadecyl, cetyl,
heptadecyl, stearyl, lauryl, and eicosyl diesters of thiodialkanoic
acids such as propionic, butanoic, pentanoic, and hexanoic acids.
Of the diester sulfides, a specific example is dilauryl,
3,3'-thiodipropionate.
[0049] The amount of the sulfurized olefin may be that amount to
provide 0.5 to 7, percent by weight sulfur to the composition, or
0.4 to 1.5, or 1.5 to 2, or 3 to 5, or 2 to 3 percent by weight.
The actual amount of the sulfurized olefin may depend on the sulfur
content thereof, as may be readily calculated. If a sulfurized
olefin contains 40 weight percent sulfur, as an example, the total
amounts may be 1.2 to 17 weight percent, or 1 to 3.8, or 3.8 to 5,
or 7.5 to 12, or 5 to 7.5 weight percent.
[0050] A sulfurized olefin composition may be prepared as described
below.
Example S-I
[0051] A sulfurized olefin is prepared by reacting sulfur, hydrogen
sulfide, and diisobutylene. Thus, 128 grams of sulfur (4 moles) is
charged to a jacketed high pressure reactor which is fitted with an
agitator and internal cooling coil. Refrigerated brine is
circulated through the coils to cool the reactor prior to the
introduction of the gaseous reactants. After sealing the reactor,
evacuating to a pressure of less than 0.5 kPa and cooling, 224
grams (2 moles) of diisobutylene and 34 grams (1 mole) of hydrogen
sulfide are charged to the reactor.
[0052] The reactor is then heated using steam in the external
jacket to a temperature of about 171.degree. C. over about 1.5
hours. A maximum pressure of 8600 kPa is reached at about
168.degree. C. during the heat-up step. Prior to reaching the
reaction temperature, the pressure starts to decrease and continues
to decrease steadily as the gaseous reactants are consumed.
[0053] After about 10 hours at a reaction temperature of about
171.degree. C., the pressure is approximately 2100-2200 kPa and the
rate of pressure drop is about 30-70 kPa per hour. At this time the
reaction is essentially complete and the unreacted hydrogen sulfide
and diisobutylene are vented to a recovery system. After the
pressure of the reactor has decreased to ambient, the sulfurized
mixture is recovered as a liquid. The mixture is then blown with
nitrogen and vacuum stripped to remove the low boiling materials
including unreacted diisobutylene, mercaptans, and monosulfides.
The residue is the desired sulfurized composition which will
contain approximately 40% sulfur by weight.
[0054] Other materials may also be present in, or may be absent
from, the disclosed lubricant compositions. One such material may
be a detergent which may optionally be an overbased detergent such
as an overbased alkaline earth metal detergent. Detergents are
typically overbased materials, otherwise referred to as overbased
or superbased salts, which are generally homogeneous Newtonian
systems having by a metal content in excess of that which would be
present for neutralization according to the stoichiometry of the
metal and the detergent anion. The amount of excess metal is
commonly expressed in terms of metal ratio, that is, the ratio of
the total equivalents of the metal to the equivalents of the acidic
organic compound. Overbased materials are prepared by reacting an
acidic material (such as carbon dioxide) with an acidic organic
compound, an inert reaction medium (e.g., mineral oil), a
stoichiometric excess of a metal base, and a promoter such as a
phenol or alcohol. The acidic organic material will normally have a
sufficient number of carbon atoms, to provide oil-solubility.
[0055] Overbased detergents may be characterized by Total Base
Number (TBN, ASTM D2896), the amount of strong acid needed to
neutralize all of the material's basicity, expressed as mg KOH per
gram of sample. Since overbased detergents are commonly provided in
a form which contains diluent oil, for the purpose of this
document, TBN is to be recalculated to an oil-free basis. Some
useful detergents may have a TBN of 100 to 800, or 150 to 750, or,
400 to 700.
[0056] The metal compounds useful in making the basic metal salts
are generally any Group 1 or Group 2 metal compounds (CAS version
of the Periodic Table of the Elements). Examples include alkali
metals such as sodium, potassium, lithium, copper, magnesium,
calcium, barium, zinc, and cadmium. In one embodiment the metals
are sodium, magnesium, or calcium. The anionic portion of the salt
can be hydroxide, oxide, carbonate, borate, or nitrate.
[0057] In one embodiment the lubricant can contain an overbased
sulfonate detergent. Suitable sulfonic acids include
hydrocarbyl-substituted sulfonic and thiosulfonic acids, including
mono- or polynuclear aromatic or cycloaliphatic compounds. In one
embodiment the sulfonate detergent may be a predominantly linear
alkylbenzenesulfonate detergent having a metal ratio of at least 8
as described in paragraphs [0026] to [0037] of US Patent
Application 2005065045.
[0058] Another overbased material is an overbased phenate
detergent. The phenols useful in making phenate detergents can be
represented by (R.sup.1).sub.a--Ar--(OH).sub.b, where R.sup.1 is an
aliphatic hydrocarbyl group of 4 to 400 or 6 to 80 or 6 to 30 or 8
to 25 or 8 to 15 carbon atoms; Ar is an aromatic group such as
benzene, toluene or naphthalene; a and b are each at least one, the
sum of a and b being up to the number of displaceable hydrogens on
the aromatic nucleus of Ar, such as 1 to 4 or 1 to 2. Phenate
detergents are also sometimes provided as sulfur-bridged
species.
[0059] In one embodiment, the overbased material is an overbased
saligenin detergent. Overbased saligenin detergents are commonly
overbased magnesium salts which are based on saligenin derivatives.
Saligenin detergents are disclosed in greater detail in U.S. Pat.
No. 6,310,009, with special reference to their methods of synthesis
(Column 8 and Example 1) and preferred amounts of the various
species of X and Y (Column 6).
[0060] Salixarate detergents are overbased materials that can be
represented by a compound comprising at least one unit of formula
(I) or formula (II) and each end of the compound having a terminal
group of formula (III) or (IV):
##STR00002##
such groups being linked by divalent bridging groups A, which may
be the same or different. In formulas (I)-(IV) R.sup.3 is hydrogen,
a hydrocarbyl group, or a valence of a metal ion; R.sup.2 is
hydroxyl or a hydrocarbyl group, and j is 0, 1, or 2; R.sup.6 is
hydrogen, a hydrocarbyl group, or a hetero-substituted hydrocarbyl
group; either R.sup.4 is hydroxyl and R.sup.5 and R.sup.7 are
independently either hydrogen, a hydrocarbyl group, or
hetero-substituted hydrocarbyl group, or else R.sup.5 and R.sup.7
are both hydroxyl and R.sup.4 is hydrogen, a hydrocarbyl group, or
a hetero-substituted hydrocarbyl group; provided that at least one
of R.sup.4, R.sup.5, R.sup.6 and R.sup.7 is hydrocarbyl containing
at least 8 carbon atoms. Salixarate derivatives and methods of
their preparation are described in greater detail in U.S. Pat. No.
6,200,936 and PCT Publication WO 01/56968. It is believed that the
salixarate derivatives have a predominantly linear, rather than
macrocyclic, structure, although both structures are intended to be
encompassed by the term "salixarate."
[0061] Glyoxylate detergents are similar overbased materials which
are based on an anionic group which may be the condensation product
of a hydroxyaromatic material such as a hydrocarbyl-substituted
phenol with a carboxylic reactant such as glyoxylic acid or another
omega-oxoalkanoic acid. Overbased glyoxylic detergents and their
methods of preparation are disclosed in greater detail in U.S. Pat.
No. 6,310,011 and references cited therein.
[0062] The overbased detergent can also be an overbased salicylate,
e,g., an alkali metal or alkaline earth metal salt of a substituted
salicylic acid. The salicylic acids may be hydrocarbyl-substituted
wherein each substituent contains an average of at least 8 carbon
atoms per substituent and 1 to 3 substituents per molecule. The
substituents can be polyalkene substituents. In one embodiment, the
hydrocarbyl substituent group contains 7 to 300 carbon atoms and
can be an alkyl group having a molecular weight of 150 to 2000.
Overbased salicylate detergents and their methods of preparation
are disclosed in U.S. Pat. Nos. 4,719,023 and 3,372,116.
[0063] Other overbased detergents can include overbased detergents
having a Mannich base structure, as disclosed in U.S. Pat. No.
6,569,818.
[0064] In certain embodiments, the hydrocarbyl substituents on
hydroxy-substituted aromatic rings in the above detergents (e.g.,
phenate, saligenin, salixarate, glyoxylate, or salicylate) are free
of or substantially free of C.sub.12 aliphatic hydrocarbyl groups
(e.g., less than 1%, 0.1%, or 0.01% by weight of the substituents
are C.sub.12 aliphatic hydrocarbyl groups). In some embodiments
such hydrocarbyl substituents contain at least 14 or at least 18
carbon atoms.
[0065] In certain embodiments an overbased alkaline earth metal
detergent may optionally be present, in an amount to provide 0 to
500, or 10 to 100, or 1 to 50 parts per million of the alkaline
earth metal or metals. In certain embodiments the lubricant is
substantially free from overbased alkaline earth metal detergent or
substantially free from all alkaline earth metal detergent, that
is, the amount of the alkaline earth metal provided thereby may be
less than 5 or 3 or 1 or 0.5 parts per million or may be zero parts
per million.
[0066] Another material that optionally may be present, or that may
be absent, is a polymeric viscosity index modifier. Viscosity
modifiers (VM) and dispersant viscosity modifiers (DVM) are well
known. Examples of VMs and DVMs may include polymethacrylates,
polyacrylates, polyolefins, styrene-maleic ester copolymers,
alpha-olefin-maleic ester copolymers, and similar polymeric
substances including homopolymers, copolymers, and graft
copolymers. The DVM may comprise a nitrogen-containing methacrylate
polymer, for example, a nitrogen-containing methacrylate polymer
derived from methyl methacrylate and dimethylaminopropyl amine.
[0067] Examples of commercially available VMs, DVMs and their
chemical types may include the following: polyisobutylenes (such as
Indopol.TM. from BP Amoco or Parapol.TM. from ExxonMobil); olefin
copolymers (such as Lubrizol.RTM. 7060, 7065, and 7067 from
Lubrizol and Lucant.RTM. polymers, including ethylene/propylene
copolymers, including Lucant.RTM. HC-2000L and HC-600 also from
Lubrizol); hydrogenated styrene-diene copolymers (such as
Shellvis.TM. 40 and 50, from Shell and LZ.RTM. 7308, and 7318 from
Lubrizol); styrene/maleate copolymers, which are dispersant
copolymers (such as LZ.RTM. 3702 and 3715 from Lubrizol);
polymethacrylates, some of which have dispersant properties (such
as those in the Viscoplex.TM. series from RohMax, such as
Viscoplex.TM. 0-050, the Hitec.TM. series of viscosity index
improver from Afton, and LZ.RTM. 7702, 7706, 7727, 7720C, 8420, and
VL9205F from Lubrizol); olefin-graft-polymethacrylate polymers
(such as Viscoplex.TM. 2-500 and 2-600 from RohMax); and
hydrogenated polyisoprene star polymers (such as Shellvis.TM. 200
and 260, from Shell). Also included are Asteric.TM. polymers from
Lubrizol (methacrylate polymers with radial or star architecture).
Viscosity modifiers that may be used are described in U.S. Pat.
Nos. 5,157,088, 5,256,752 and 5,395,539. The VMs and/or DVMs may be
used in the lubricant at concentrations of 0 to 30 percent by
weight, or 3 to 25, or 5 to 20, or 5 to 15 weight percent.
[0068] Additional conventional components may be used in preparing
a lubricant according to the disclosed technology, for instance,
those additives typically employed in a gear lubricant. Gear
lubricants may typically contain any or all of the following
components hereinafter described; alternatively, any one or more of
the following components may optionally be omitted.
[0069] One additive is a dispersant. Dispersants are well known in
the field of lubricants and include primarily what is known as
ashless-type dispersants and polymeric dispersants. Ashless type
dispersants are characterized by a polar group attached to a
relatively high molecular weight hydrocarbon chain. Typical ashless
dispersants include nitrogen-containing dispersants such as
N-substituted long chain alkenyl succinimides, also known as
succinimide dispersants. Succinimide dispersants are more fully
described in U.S. Pat. Nos. 4,234,435 and 3,172,892. Another class
of ashless dispersant is high molecular weight esters, prepared by
reaction of a hydrocarbyl acylating agent and a polyhydric
aliphatic alcohol such as glycerol, pentaerythritol, or sorbitol.
Such materials are described in more detail in U.S. Pat. No.
3,381,022. Another class of ashless dispersant is Mannich bases.
These are materials which are formed by the condensation of a
higher molecular weight, alkyl substituted phenol, an alkylene
polyamine, and an aldehyde such as formaldehyde and are described
in more detail in U.S. Pat. No. 3,634,515. Other dispersants
include polymeric dispersant additives, which are generally
hydrocarbon-based polymers which contain polar functionality to
impart dispersancy characteristics to the polymer. Dispersants can
also be post-treated by reaction with any of a variety of agents.
Among these are urea, thiourea, dimercaptothiadiazoles, carbon
disulfide, aldehydes, ketones, carboxylic acids,
hydrocarbon-substituted succinic anhydrides, nitriles, epoxides,
boron compounds, and phosphorus compounds. References detailing
such treatment are listed in U.S. Pat. No. 4,654,403. The amount of
dispersant in the present composition can typically be 1 to 10
weight percent, or 1.5 to 9.0 percent, or 2.0 to 8.0 percent, all
expressed on an oil-free basis.
[0070] Another component is an antioxidant. Antioxidants encompass
phenolic antioxidants, which may comprise a butyl substituted
phenol containing 2 or 3 t-butyl groups. The para position may also
be occupied by a hydrocarbyl group, an ester-containing group, or a
group bridging two aromatic rings. Antioxidants also include
aromatic amine, such as nonylated diphenylamines or alkylated
phenylnaphthylamine. Other antioxidants include sulfurized olefins,
titanium compounds, and molybdenum compounds. U.S. Pat. No.
4,285,822, for instance, discloses lubricating oil compositions
containing a molybdenum and sulfur containing composition. U.S.
Patent Application Publication 2006-0217271 discloses a variety of
titanium compounds, including titanium alkoxides and titanated
dispersants, which materials may also impart improvements in
deposit control and filterability. Other titanium compounds include
titanium carboxylates such as neodecanoate. Typical amounts of
antioxidants will, of course, depend on the specific antioxidant
and its individual effectiveness, but illustrative total amounts
can be 0.01 to 5 percent by weight or 0.15 to 4.5 percent or 0.2 to
4 percent. Additionally, more than one antioxidant may be present,
and certain combinations of these can be synergistic in their
combined overall effect.
[0071] Another additive is an antiwear agent, other than those that
have been described above. Examples of anti-wear agents include
phosphorus-containing antiwear/extreme pressure agents such as
metal thiophosphates, phosphoric acid esters and salts thereof,
phosphorus-containing carboxylic acids, esters, ethers, and amides;
and phosphites. In certain embodiments a phosphorus antiwear agent
may be present in an amount to deliver 0.01 to 0.2, or 0.015 to
0.15, or 0.02 to 0.1, or 0.025 to 0.08 percent phosphorus. The
antiwear agent may be a zinc dialkyldithiophosphate (ZDP). For a
typical ZDP, which may contain 11 percent P (calculated on an oil
free basis), suitable amounts may include 0.09 to 0.82 percent.
Non-phosphorus-containing anti-wear agents include borate esters
(including borated epoxides), dithiocarbamate compounds,
molybdenum-containing compounds, and sulfurized olefins.
[0072] Other materials that may be used as antiwear agents include
tartrate esters, tartramides, and tartrimides. Examples include
oleyl tartrimide (the imide formed from oleylamine and tartaric
acid) and oleyl diesters (from, e.g., mixed C12-16 alcohols). Other
related materials that may be useful include esters, amides, and
imides of other hydroxy-carboxylic acids in general, including
hydroxy-polycarboxylic acids, for instance, acids such as tartaric
acid, citric acid, lactic acid, glycolic acid, hydroxy-propionic
acid, hydroxyglutaric acid, and mixtures thereof. These materials
may also impart additional functionality to a lubricant beyond
antiwear performance. These materials are described in greater
detail in US Publication 2006-0079413 and PCT publication
WO2010/077630. Such derivatives of (or compounds derived from) a
hydroxy-carboxylic acid, if present, may typically be present in
the lubricating composition in an amount of 0.1 weight % to 5
weight %, or 0.2 weight % to 3 weight %, or greater than 0.2 weight
% to 3 weight %.
[0073] Other additives that may optionally be used in lubricating
oils include pour point depressing agents, extreme pressure agents,
anti-wear agents, color stabilizers, and anti-foam agents.
[0074] The amount of each chemical component described is presented
exclusive of any solvent or diluent oil, which may be customarily
present in the commercial material, that is, on an active chemical
basis, unless otherwise indicated. However, unless otherwise
indicated, each chemical or composition referred to herein should
be interpreted as being a commercial grade material which may
contain the isomers, by-products, derivatives, and other such
materials which are normally understood to be present in the
commercial grade.
[0075] As used herein, the term "hydrocarbyl substituent" or
"hydrocarbyl group" is used in its ordinary sense, which is
well-known to those skilled in the art. Specifically, it refers to
a group having a carbon atom directly attached to the remainder of
the molecule and having predominantly hydrocarbon character.
Examples of hydrocarbyl groups include:
[0076] hydrocarbon substituents, that is, aliphatic (e.g., alkyl or
alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents,
and aromatic-, aliphatic-, and alicyclic-substituted aromatic
substituents, as well as cyclic substituents wherein the ring is
completed through another portion of the molecule (e.g., two
substituents together form a ring);
[0077] substituted hydrocarbon substituents, that is, substituents
containing non-hydrocarbon groups which, in the context of this
invention, do not alter the predominantly hydrocarbon nature of the
substituent (e.g., halo (especially chloro and fluoro), hydroxy,
alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);
[0078] hetero substituents, that is, substituents which, while
having a predominantly hydrocarbon character, in the context of
this invention, contain other than carbon in a ring or chain
otherwise composed of carbon atoms and encompass substituents as
pyridyl, furyl, thienyl and imidazolyl. Heteroatoms include sulfur,
oxygen, and nitrogen. In general, no more than two, or no more than
one, non-hydrocarbon substituent will be present for every ten
carbon atoms in the hydrocarbyl group; alternatively, there may be
no non-hydrocarbon substituents in the hydrocarbyl group.
[0079] It is known that some of the materials described above may
interact in the final formulation, so that the components of the
final formulation may be different from those that are initially
added. For instance, metal ions (of, e.g., a detergent) can migrate
to other acidic or anionic sites of other molecules. The products
formed thereby, including the products formed upon employing the
composition of the present invention in its intended use, may not
be susceptible of easy description. Nevertheless, all such
modifications and reaction products are included within the scope
of the present invention; the present invention encompasses the
composition prepared by admixing the components described
above.
[0080] The invention herein is useful for imparting wear
performance to a lubricant such as a gear lubricant formulation,
which may be better understood with reference to the following
examples.
Examples
[0081] Typical gear lubricant formulations are prepared in low
KV_100 formulations. Details of the formulations are presented in
the Table below. All amounts are on an oil-free (active chemical)
basis except for the commercial anti-foam agent(s) which are
reported as provided commercially (believed to contain 65-90%
oil).
TABLE-US-00001 Ex. (ID # for reference) 1* 2* 3* 4 5 6 7 8 295 296
298 316 348 349 351 353 Poly alpha olefin oil, 77.2 77.2 77.2 75.5
75.5 75.5 75.5 75.5 KV_100 = 4 mm.sup.2/s Amine salt of -- -- --
1.66 0.83 0.50 0.65 1.25 P compound.sup.a di-C18 alkyl phosphite
0.5 0.5 0.5 0.8 0.5 0.5 0.5 0.4 di-C8 alkyl phosphate, 1.3 1.3 1.5
0.8 1.0 1.0 1.0 0.4 C8 amine salt % P in composition 0.128 0.126
0.143 0.224 0.176 0.148 0.157 0.160 Sulfurized C4 olefins 4.2 4.6
4.2 4.1 4.1 4.1 4.1 4.0 (44% S) % S in composition 1.85 2.02 1.85
1.80 1.80 1.80 1.80 1.76 KV_100 of composition 5.9 5.9 5.9 6.0 6.0
6.0 6.0 6.0 Additional components Ester polymer viscosity 12.5 12.5
12.5 12.5 12.5 12.5 12.5 12.5 modifier Corrosion inhibitors 0.7 0.7
0.7 0.65 0.65 0.65 0.65 0.65 Borated dispersant 0.67 0.67 0.67 0.72
1.00 1.00 1.00 1.00 Antifoam agents 0.07 0.07 0.07 0.02 0.02 0.02
0.02 0.02 Ester of hydroxy acid 0.08 0.11 0.11 0.08 0.08 0.08 0.10
0.10 Friction modifier(s).sup.c 0.04 0.04 0.04 0.32 0.32 0.32 0.12
0.12 Wear test results L-37 ring gear wear rating 7 7 7 9/8 9 9 9 9
(ASTM D6121) *a reference or comparative example .sup.aobtained by
reacting phosphorus pentasulfide alcohol of 4-8 carbon atoms, with
an alkylene oxide and further with phosphorus pentoxide, and
salting the resulting material with amine having 12 to 24 carbon
atoms. .sup.blong chain amine, amide, and/or imidazoline compounds
.sup.cThe friction modifiers are non-phosphorus-containing
materials. It is known to those skilled in the art that L-37 test
performance depends on the presence of phosphorus-containing
component(s). The minor variations in the amount or composition of
the friction modifiers will not affect the L-37 wear results.
[0082] The results show that the presence of the amine salt of the
phosphorus compound provides improved wear performance compared
with the other phosphorus compounds, in a low viscosity lubricant
formulation.
[0083] Another series of examples were prepared in relatively low
and in high viscosity formulations. The formulations are summarized
in the table below:
TABLE-US-00002 Ex. (ID # for reference) 9* (390) 10* (739) 11 (391)
12* (770) Low visc. High visc. Low visc. High visc. Group II base
oil, 91 91 6 mm.sup.2/s Group I base oil, 77.4 77.4 12 mm.sup.2/s
Bright stock, 31 mm.sup.2/s 13.6 13.6 Amine salt of 1.16 1.16 P
compound.sup.a Di-C8 alkyl phosphate, 0.85 0.85 C8 amine salt
Dialkyl phosphite 0.42 0.42 anti-wear agents Sulfurized olefin 3.2
3.2 3.2 3.2 (45% S) Borated dispersant 0.59 0.59 0.59 0.59 Other
components 1.54 1.54 1.86 1.86 including friction modifier,
corrosion inhibitors, pour point depressant Diluent oil Balance to
= 100% KV_100 of the 6.12 13.12 6.09 13.1 composition *A
comparative or reference example .sup.aobtained by reacting
phosphorus pentasulfide alcohol of 4-8 carbon atoms, with an
alkylene oxide and further with phosphorus pentoxide, and salting
the resulting material with amine having 12 to 24 carbon atoms.
[0084] The formulations of Examples 9-12 are subjected to the L-37
test (ASTM D6121). The results, including the pass criteria, are
shown in the table below:
TABLE-US-00003 Ex.: Test value (pass criterion) 9* 10* 11 12* Final
ring gear wear (>5) 8 7 7 8 Final ring gear surface 9 9 9 10
fatigue rippling (>8) Final ring gear surface 9 10 10 10 fatigue
ridging (>8) Final ring gear surface fatigue 9.9 9.9 9.9 9.9
pitting/spalling (>9.3) Final ring gear surface 10 10 10 10
fatigue scoring (>9.3) Final pinion gear wear (>5) 6 7 7 8
Final pinion gear rippling (>8) 8.7 9.4 9.4 9 Final pinion gear
surface 7.3 8 8 10 ridging (>8) Final pinion gear
pitting/spalling 9.9 9.9 9.9 9.9 merit (>9.3) Final pinion gear
scoring (>9.3) 10 10 10 10
[0085] The result show that, using the formulations of examples
9-12, both the compositions of the disclosed technology and the
reference compositions meet all the passing criteria when used in a
high viscosity formulation (10 and 12). However, in the low
viscosity formulations (9 and 11), the formulation containing the
amine phosphorus salt disclosed herein meets all the passing
criteria, while the formulation containing the alternative
phosphorus compound does not meet at least one of the passing
criteria.
[0086] Each of the documents referred to above is incorporated
herein by reference, including any prior applications, whether or
not specifically listed above, from which priority is claimed. The
mention of any document is not an admission that such document
qualifies as prior art or constitutes the general knowledge of the
skilled person in any jurisdiction. Except in the Examples, or
where otherwise explicitly indicated, all numerical quantities in
this description specifying amounts of materials, reaction
conditions, molecular weights, number of carbon atoms, and the
like, are to be understood as optionally modified by the word
"about." It is to be understood that the upper and lower amount,
range, and ratio limits set forth herein may be independently
combined. Similarly, the ranges and amounts for each element of the
invention can be used together with ranges or amounts for any of
the other elements.
[0087] As used herein, the transitional term "comprising," which is
synonymous with "including," "containing," or "characterized by,"
is inclusive or open-ended and does not exclude additional,
un-recited elements or method steps. However, in each recitation of
"comprising" herein, it is intended that the term also encompass,
as alternative embodiments, the phrases "consisting essentially of"
and "consisting of," where "consisting of" excludes any element or
step not specified and "consisting essentially of" permits the
inclusion of additional un-recited elements or steps that do not
materially affect the essential or basic and novel characteristics
of the composition or method under consideration. The expression
"consisting of" or "consisting essentially of," when applied to an
element of a claim, is intended to restrict all species of the type
represented by that element, notwithstanding the presence of
"comprising" elsewhere in the claim.
[0088] While certain representative embodiments and details have
been shown for the purpose of illustrating the subject invention,
it will be apparent to those skilled in this art that various
changes and modifications can be made therein without departing
from the scope of the subject invention. In this regard, the scope
of the invention is to be limited only by the following claims.
* * * * *