U.S. patent application number 11/242269 was filed with the patent office on 2007-04-05 for lubricant formulations containing extreme pressure agents.
Invention is credited to Darrin Keith Doerfler, Abbas Kadkhodayan, Jeffrey L. Milner.
Application Number | 20070078066 11/242269 |
Document ID | / |
Family ID | 37685674 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070078066 |
Kind Code |
A1 |
Milner; Jeffrey L. ; et
al. |
April 5, 2007 |
Lubricant formulations containing extreme pressure agents
Abstract
A method for improving the solubility of a sulfurized extreme
pressure agent in a lubricant composition and improved lubricant
compositions and uses therefor. The method includes pre-blending
organic acid and amine components of a lubricant additive package
for the lubricant composition to provide a premixture of organic
acid and amine components. The premixture is combined with a
sulfurized extreme pressure agent having a viscosity of less than
about 5.5 centistokes at 100.degree. C. to provide a lubricant
additive package. By use of the foregoing process, a turbidity
characteristic of the lubricant composition containing the additive
package is lower than a turbidity characteristic of a lubricant
composition that is made by combining the organic acid and amine
components with the sulfurized extreme pressure agent in the
absence of the premixture.
Inventors: |
Milner; Jeffrey L.;
(Chesterfield, VA) ; Kadkhodayan; Abbas;
(Collinsville, IL) ; Doerfler; Darrin Keith;
(O'Fallon, IL) |
Correspondence
Address: |
NEW MARKET SERVICES CORPORATION;(FORMERLY ETHYL CORPORATION)
330 SOUTH 4TH STREET
RICHMOND
VA
23219
US
|
Family ID: |
37685674 |
Appl. No.: |
11/242269 |
Filed: |
October 3, 2005 |
Current U.S.
Class: |
508/337 |
Current CPC
Class: |
C10N 2040/04 20130101;
C10N 2020/02 20130101; C10M 2215/223 20130101; C10M 141/08
20130101; C10M 2207/10 20130101; C10M 2215/02 20130101; C10N
2030/66 20200501; C10M 2209/084 20130101; C10M 169/044 20130101;
C10M 2205/0206 20130101; C10M 2219/106 20130101; C10M 169/04
20130101; C10M 2219/022 20130101; C10M 2203/1006 20130101; C10M
2223/04 20130101 |
Class at
Publication: |
508/337 |
International
Class: |
C10M 135/06 20060101
C10M135/06 |
Claims
1. A method for improving the solubility of a sulfurized extreme
pressure agent in a lubricant composition comprising a
substantially non-polar base oil component, the method comprising
pre-blending organic acid and amine components of a lubricant
additive package for the lubricant composition to provide a
premixture of organic acid and amine components and combining the
premixture with a sulfurized extreme pressure agent having a
viscosity of less than about 5.5 centistokes at 100.degree. C. to
provide a lubricant additive package, whereby a turbidity
characteristic of the lubricant composition containing the additive
package is lower than a turbidity characteristic of a lubricant
composition that is made by combining the organic acid and amine
components with the sulfurized extreme pressure agent in the
absence of the premixture.
2. The method of claim 1, wherein the sulfurized extreme pressure
agent comprises a sulfurized olefin.
3. The method of claim 2, wherein the sulfurized olefin comprises
sulfurized isobutylene.
4. The method of claim 1, further comprising combining the
lubricant additive package with the substantially non-polar base
oil component.
5. The method of claim 4, wherein the substantially non-polar base
oil component comprises a polyolefin base oil.
6. The method of claim 1, wherein the substantially non-polar base
oil component comprises a polyolefin base oil.
7. The method of claim 1, wherein the substantially non-polar base
oil component comprises a base oil selected from the group
consisting of a Group II base oil, a Group III base oil, and a
Group IV base oil.
8. A gear lubricant made by the method of claim 1.
9. A vehicle having moving parts containing the gear lubricant of
claim 8 for lubricating the moving parts.
10. In a process for making a lubricant containing an extreme
pressure agent, the improvement comprising combining at least
organic acid and amine components of an additive package for the
lubricant to provide a mixture, and, subsequently, combining the
mixture with a sulfurized extreme pressure agent and a base oil to
provide the lubricant, wherein the sulfurized extreme pressure
agent is made by a process that provides a viscosity of the extreme
pressure agent in a range that enhances the solubility of the
extreme pressure agent in the lubricant.
11. The process of claim 10, wherein the sulfurized extreme
pressure agent comprises a sulfurized olefin.
12. The process of claim 11, wherein the sulfurized olefin
comprises sulfurized isobutylene.
13. The process of claim 12, wherein the sulfurized isobutylene has
a viscosity at 100.degree. C. of no higher than about 5.5
centistokes.
14. The process of claim 10, wherein the base oil comprises a
substantially non-polar base oil component.
15. The process of claim 14 wherein the substantially non-polar
base oil component comprises a polyolefin base oil.
16. A gear lubricant made by the process of claim 10.
17. A vehicle having moving parts containing the gear lubricant of
claim 16 for lubricating the moving parts.
18. A method for producing a non-hazy lubricant composition
containing a sulfurized extreme pressure agent and a substantially
non-polar base oil component, the method comprising the steps of:
reacting a sulfur monochloride/isobutylene adduct with aqueous
sodium hydrosulfide under conditions sufficient to provide a
sulfurized isobutylene having a viscosity at 100.degree. C. no
higher than about 5.5 centistokes; pre-blending organic acid and
amine components of the lubricant composition to provide an
additive package pre-mix; subsequently, combining the additive
package pre-mix with from about 50 to about 95 percent by weight of
the sulfurized isobutylene to provide the additive composition; and
treating a base oil with the additive composition to provide the
non-hazy lubricant composition.
19. The method of claim 18, wherein the substantially non-polar
base oil component comprises a polyolefin base oil.
20. A gear lubricant comprising a mineral oil component and an
additive composition made by the method of claim 18.
21. A vehicle having moving parts containing the gear lubricant of
claim 20 for lubricating the moving parts.
22. A method for making a sulfurized extreme pressure agent having
characteristics that assist in the formation of a low turbidity
substantially non-polar base oil containing lubricant, the method
comprising the steps of: reacting sulfur monochloride and an olefin
under conditions sufficient to provide a sulfur/olefin adduct;
mixing and reacting the sulfur/olefin adduct with an aqueous sulfur
source over a period of time sufficient to provide a sulfurized
extreme pressure agent in an organic phase having a viscosity of no
higher than about 5.5 centistokes at 100.degree. C.; and separating
an aqueous phase and the organic phase containing the sulfurized
extreme pressure agent from one another.
23. The method of claim 22, wherein the sulfurized extreme pressure
agent comprises sulfurized isobutylene.
24. The method of claim 23, wherein the sulfurized isobutylene has
a viscosity ranging from about 4.0 to about 5.5 centistokes at
100.degree. C.
25. The method of claim 23, wherein the sulfurized isobutylene has
a sulfur content ranging from about 40 to about 50 percent by
weight.
26. The method of claim 22, wherein the step of mixing and reacting
the sulfur/olefin adduct with an aqueous sulfur source is conducted
over a period of time ranging from about 10 to less than about 60
minutes.
Description
FIELD OF THE DISCLOSURE
[0001] The disclosure relates to lubricant formulations and in
particular to lubricant formulations having enhanced stability and
to methods for making lubricants having improved properties.
BACKGROUND AND SUMMARY
[0002] Lubricants may be formulated to contain extreme pressure
agents for use in particular applications. A wide variety of
extreme pressure agents exist. Particularly useful extreme pressure
agents are those containing sulfur. However, sulfuirized extreme
pressure agents are often difficult to handle, highly odiferous,
expensive, or require the presence of compatibilizing components
when used in lubricant formulations.
[0003] Accordingly, there continues to be a need for improved
lubricant formulations containing extreme pressure components.
[0004] With regard to the foregoing, a method for improving the
solubility of a sulfurized extreme pressure agent in a lubricant
composition and improved lubricant compositions and uses therefor
are provided. The method includes pre-blending organic acid and
amine components of a lubricant additive package for the lubricant
composition to provide a premixture of organic acid and amine
components. The premixture is combined with a sulfurized extreme
pressure agent having a viscosity of less than about 5.5
centistokes at 100.degree. C. to provide a lubricant additive
package. By use of the foregoing process, a turbidity
characteristic of the lubricant composition containing the additive
package is lower than a turbidity characteristic of a lubricant
composition that is made by combining the organic acid and amine
components with the sulfurized extreme pressure agent in the
absence of the premixture.
[0005] In another exemplary embodiment, there is provided a method
for producing a non-hazy lubricant composition containing a
sulfurized extreme pressure agent and a substantially non-polar
base oil component. The sulfurized extreme pressure agent is
provided by a sulfur monochloride/isobutylene adduct that is
reacted with aqueous sodium hydrosulfide under conditions
sufficient to provide a sulfurized isobutylene having a viscosity
at 100.degree. C. no higher than about 5.5 centistokes. Organic
acid and amine components of the lubricant composition are
pre-blended together to provide an additive package pre-mix. The
additive package pre-mix is subsequently combined with from about
50 to about 95 percent by weight of the sulfurized isobutylene to
provide the additive composition. A base oil is treated with the
additive composition to provide the non-hazy lubricant
composition.
[0006] Another exemplary embodiment of the disclosure provides a
method for making a sulfurized extreme pressure agent having
characteristics that assist in the formation of a low turbidity
substantially non-polar base oil containing lubricant. The method
includes reacting sulfur monochloride and an olefin under
conditions sufficient to provide a sulfur/olefin adduct. The
sulfur/olefin adduct is mixed and reacted with an aqueous sulfur
source over a period of time sufficient to provide a sulfurized
extreme pressure agent in an organic phase having a viscosity of no
higher than about 5.5 centistokes at 100.degree. C. After the
reaction is complete, an aqueous phase and the organic phase
containing the sulfurized extreme pressure agent are separated from
one another.
[0007] An advantage of exemplary embodiments described herein is
that difficult to solubilize additive components are made more
soluble in finished lubricant compositions without the need for
solubilizing agents or more expensive extreme pressure agents.
Accordingly, solubilizing agents may be eliminated and/or less
expensive components may be substituted for more expensive
components. In particular, it has been found, quite surprisingly,
that combining sulfurized extreme pressure agents having a
relatively low viscosity with other components of an additive
concentrate for a gear lubricant after combining organic acid and
amine components substantially increases the solubility of the
components in a finished lubricant composition.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0008] 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:
[0009] (1) 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 an alicyclic radical);
[0010] (2) substituted hydrocarbon substituents, that is,
substituents containing non-hydrocarbon groups which do not alter
the predominantly hydrocarbon substituent (e.g., halo (especially
chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto,
nitro, nitroso, and sulfoxy);
[0011] (3) hetero substituents, that is, substituents which, while
having a predominantly hydrocarbon character, contain other than
carbon in a ring or chain otherwise composed of carbon atoms.
Heteroatoms include sulfur, oxygen, nitrogen, and encompass
substituents as pyridyl, furyl, thienyl and imidazolyl. In general,
no more than two, typically no more than one, non-hydrocarbon
substituent will be present for every ten carbon atoms in the
hydrocarbyl group; typically, there will be no non-hydrocarbon
substituents in the hydrocarbyl group.
[0012] As used herein, the term "percent by weight", unless
expressly stated otherwise, means the percentage the recited
component represents to the weight of the entire composition.
[0013] Finished gear oils made according to exemplary embodiments
described herein may have different primary viscosity grades which
are indicated by the maximum temperature for viscosity of 150,000
cP according to ASTM D 2983 as defined in SAE J306 Automotive Gear
and Lubricant Viscosity Classification. Accordingly, gear oil
formulations described herein typically contain a major amount of
base oil, e.g., from about 75 to about 98 percent by weight base
oil, and a minor amount of functional additive or additive
concentrate, e.g., from about 2 to about 25 percent by weight
additive concentrate.
Base Oils
[0014] The gear oils of the compositions described herein may be
based on natural or synthetic oils, or blends thereof, provided the
lubricant has a suitable viscosity for use in gear oil
applications. Thus, the base oils will normally have a viscosity in
the range of SAE 50 to SAE 250, and more usually will range from
SAE 70W to SAE 140. Suitable automotive gear oils also include
multi-grade oils such as 75W-140, 80W-90, 85W-140, 85W-90, and the
like.
[0015] Basestocks suitable for providing the base oils may be made
using a variety of different processes including but not limited to
distillation, solvent refining, hydrogen processing,
oligomerization, esterification, and re-refining. API 1509 "Engine
Oil Licensing and Certification System" Fourteenth Edition,
December 1996 states that all basestocks are divided into five
general categories:
[0016] Group I contain less than 90 wt. % saturates and/or greater
than 0.03 wt. % sulfur and have a viscosity index greater than or
equal to 80 and less than 120;
[0017] Group II contain greater than or equal to 90 wt. % saturates
and less than or equal to 0.03 wt. % sulfur and have a viscosity
index greater than or equal to 80 and less than 120;
[0018] Group III contain greater than or equal to 90 wt. %
saturates and less than or equal to 0.03 wt. % sulfur and have a
viscosity index greater than or equal to 120;
[0019] Group IV are polyalphaolefins (PAO); and
[0020] Group V include all other basestocks not included in Group
I, II, III or IV.
[0021] The test methods used in defining the above groups are ASTM
D2007 for saturates; ASTM D2270 for viscosity index; and one of
ASTM D2622, 4294, 4927 and 3120 for sulfur.
[0022] Group IV basestocks, i.e. polyalphaolefins (PAO) include
hydrogenated oligomers of an alpha-olefin, the most important
methods of oligomerization being free radical processes, Ziegler
catalysis, and cationic, Friedel-Crafts catalysis.
[0023] The polyalphaolefins typically have viscosities in the range
of 2 to 100 cSt at 100.degree. C., desirably 4 to 8 cSt at
100.degree. C. They may, for example, be oligomers of branched or
straight chain alpha-olefins having from 2 to 16 carbon atoms,
specific examples being polypropenes, polyisobutenes,
poly-1-butenes, poly-1-hexenes, poly-1-octenes and poly-1-decene.
Included are homopolymers, interpolymers and mixtures.
[0024] Base oils may include a single basestock or mixtures of
basestocks. In exemplary embodiments described herein, the base oil
contains at least one basestock having a substantially non-polar
characteristic. For example, a base oil may be a mixture of a minor
amount of a Group I basestock and a major amount of a Group II,
Group III, or Group IV basestock.
[0025] Some additive components are supplied in the form of
solutions of active ingredient(s) in an inert diluent or solvent,
such as a diluent oil or mineral oil. Unless expressly stated to
the contrary, the amounts and concentrations of each additive
component are expressed in terms of active additive, i.e., the
amount of solvent or diluent that may be associated with such
component as received is excluded.
[0026] As set forth above, a gear lubricant typically contains one
or more additives. The additives may be selected from the group
consisting of dispersants, corrosion inhibitors, extreme pressure
additives, anti-wear additives, rust inhibitors, antioxidants,
deodorizers, defoamers, demulsifiers, dyes, friction modifiers,
seal swell agents, and fluorescent coloring agents. The additive
package may be, although it does not have to be, a fully-formulated
gear additive package, such as a package meeting the requirements
for API GL-5 and/or API MT-1 and/or MIL-PRF-2105E and/or AGMA
9005-D94. The type and amount of the components present in the
additive package will depend on the intended final use of the
product.
Dispersant
[0027] The dispersants which may be used include at least one
oil-soluble ashless dispersant having a basic nitrogen and/or at
least one hydroxyl group in the molecule. Suitable dispersants
include alkenyl succinimides, alkenyl succinic acid esters, alkenyl
succinic ester-amides, Mannich bases, hydrocarbyl polyamines, or
polymeric polyamines.
[0028] The alkenyl succinimides in which the succinic group
contains a hydrocarbyl substituent containing at least 30 carbon
atoms are described for example in U.S. Pat. Nos. 3,172,892;
3,202,678; 3,216,936; 3,219,666; 3,254,025; 3,272,746; and
4,234,435. The alkenyl succinimides may be formed by conventional
methods such as by heating an alkenyl succinic anhydride, acid,
acid-ester, acid halide, or lower alkyl ester with a polyamine
containing at least one primary amino group. The alkenyl succinic
anhydride may be made readily by heating a mixture of olefin and
maleic anhydride to, for example, about 180-220.degree. C. The
olefin may be a polymer or copolymer of a lower mono-olefin such as
ethylene, propylene, 1-butene, isobutene and the like and mixtures
thereof. An alkenyl group source may be from polyisobutene having a
gel permeation chromotography (GPC) number average molecular weight
of up to 10,000 or higher, generally in the range of about 500 to
about 2,500, and typically in the range of about 800 to about
1,500.
[0029] As used herein the term "succinimide" is meant to encompass
the completed reaction product from reaction between one or more
polyamine reactants and a hydrocarbon-substituted succinic acid or
anhydride (or like succinic acylating agent), and is intended to
encompass compounds wherein the product may have amide, amidine,
and/or salt linkages in addition to the imide linkage of the type
that results from the reaction of a primary amino group and an
anhydride moiety.
[0030] The various types of ashless dispersants described above can
be phosphorylated by procedures described in U.S. Pat. Nos.
3,184,411; 3,342,735; 3,403,102; 3,502,607; 3,511,780; 3,513,093;
4,615,826; 4,648,980; 4,857,214 and 5,198,133.
[0031] The dispersants may also be selected from boronated
dispersants. Methods for boronating (borating) the various types of
ashless dispersants described above are described in U.S. Pat. Nos.
3,087,936; 3,254,025; 3,281,428; 3,282,955; 2,284,409; 2,284,410;
3,338,832; 3,344,069; 3,533,945; 3,658,836; 3,703,536; 3,718,663;
4,455,243; and 4,652,387.
[0032] Procedures for phosphorylating and boronating ashless
dispersants such as those referred to above are set forth in U.S.
Pat. Nos. 4,857,214 and 5,198,133.
[0033] The amount of ashless dispersant, when present, on an
"active ingredient basis" (i.e., excluding the weight of
impurities, diluents and solvents typically associated therewith)
is generally within the range of about 0.5 to about 7.5 weight
percent, typically within the range of about 0.5 to 5.0 wt. %,
desirably within the range of about 0.5 to about 3.0 wt. %, and
more desirably within the range of about 2.0 to about 3.0 wt. %,
based on the finished oil.
Corrosion Inhibitors
[0034] Copper corrosion inhibitors which may be used include
thiazoles, triazoles and thiadiazoles. Examples include
benzotriazole, tolyltriazole, octyltriazole, decyltriazole,
dodecyltriazole, 2-mercaptobenzothiazole,
2,5-dimercapto-1,3,4-thiadiazole,
2-mercapto-5-hydrocarbylthio-1,3,4-thiadiazoles,
2-mercapto-5-hydrocarbyldithio-1,3,4-thiadiazoles,
2,5-bis(hydrocarbylthio)-1,3,4-thiadiazoles, and
2,5-bis-(hydrocarbyldithio)-1,3,4-thiadiazoles. Suitable compounds
are the 1,3,4-thiadiazoles, especially the
2-hydrocarbyldithio-5-mercapto-1,3,4-dithiadiazoles and the
2,5-bis(hydrocarbyldithio)-1,3,4-thiadiazoles, and mixtures
thereof, a number of which are available as articles of
commerce.
[0035] Other suitable inhibitors of copper corrosion include ether
amines; polyethoxylated compounds such as ethoxylated amines,
ethoxylated phenols, and ethoxylated alcohols; imidazolines; and
the like. See, for example, U.S. Pat. Nos. 3,663,561 and 4,097,387.
Concentrations of up to about 3 wt. % in the concentrate are
typical. Suitable copper corrosion inhibitors include ashless
dialkyl thiadiazoles. Such ashless dialkyl thiadiazoles are
available from Afton Chemical Corporation of Richmond, Va.
[0036] Dialkyl thiadiazoles which may be used are of the general
formula: ##STR1## wherein R.sup.1 is a hydrocarbyl substituent
having from 6 to 18 carbon atoms; R.sup.2 is a hydrocarbyl
substituent having from 6 to 18 carbon atoms; and may be the same
as or different from R.sup.1. Generally, R.sup.1 and R.sup.2 are
about 9-12 carbon atoms, and typically R.sup.1 and R.sup.2 are each
9 carbon atoms.
[0037] Mixtures of dialkyl thiadiazoles of formula (I) with
monoalkyl thiadiazoles may also be used within the scope of the
exemplary embodiments. Such mono alkyl thiadiazoles occur when
either substituent R.sup.1 or R.sup.2 is H.
Extreme Pressure Agents
[0038] The gear oils formulations of the disclosure may contain at
least one sulfur-containing extreme pressure (EP) agent. The
sulfur-containing extreme pressure agent may contain at least 25
percent by weight sulfur. The amount of said EP agent added to the
gear oil is typically sufficient to provide at least 10,000 ppm
sulfur, desirably from about 10,000 to about 30,000 ppm sulfur, and
more desirably from about 12,000 to about 25,000 ppm sulfur in the
finished gear oil formulation.
[0039] A wide variety of sulfur-containing extreme pressure or
antiwear agents are available for use in the exemplary embodiments
described herein. Among suitable compositions for this use are
included sulfurized animal or vegetable fats or oils, sulfurized
animal or vegetable fatty acid esters, fully or partially
esterified esters of trivalent or pentavalent acids of phosphorus,
sulfurized olefins (see for example U.S. Pat. Nos. 2,995,569;
3,673,090; 3,703,504; 3,703,505; 3,796,661; 3,873,454 4,119,549;
4,119,550; 4,147,640; 4,191,659; 4,240,958; 4,344,854; 4,472,306;
and 4,711,736), dihydrocarbyl polysulfides (see for example U.S.
Pat. Nos. 2,237,625; 2,237,627; 2,527,948; 2,695,316; 3,022,351;
3,308,166; 3,392,201; 4,564,709; and British 1,162,334),
functionally-substituted dihydrocarbyl polysulfides (see for
example U.S. Pat. No. 4,218,332), and polysulfide olefin products
(see for example U.S. Pat. No. 4,795,576).
[0040] Another class of such agents is that of polysulfides
composed of one or more compounds represented by the formula:
R.sup.6--S.sub.x--R.sup.7 where R.sup.6 and R.sup.7 are hydrocarbyl
groups each of which may contain 3 to 18 carbon atoms and x is may
be in the range of from 2 to 8, and typically in the range of from
2 to 5, especially 3. The hydrocarbyl groups can be of widely
varying types such as alkyl, cycloalkyl, alkenyl, aryl, or aralkyl.
Tertiary alkyl polysulfides such as di-tert-butyl trisulfide, and
mixtures comprising di-tert-butyl trisulfide (e.g., a mixture
composed principally or entirely of the tri, tetra-, and
pentasulfides) may be used. Examples of other useful dihydrocarbyl
polysulfides include the diamyl polysulfides, the dinonyl
polysulfides, the didodecyl polysulfides, and the dibenzyl
polysulfides.
[0041] One particularly suitable class of extreme pressure agent is
made by reacting an olefin, such as isobutene, with sulfur. The
product, e.g., sulfurized isobutene (SIB), notably sulfurized
polyisobutylene, typically has a sulfur content of from about 10 to
about 55%, desirably from about 30 to about 50% by weight. A wide
variety of other olefins or unsaturated hydrocarbons, e.g.,
isobutene dimer or trimer, may be used to form the sulfurized
olefin extreme pressure agents. Various methods have been disclosed
in the prior art for the preparation of sulfurized olefins. See,
for example, U.S. Pat. No. 3,471,404 to Myers; U.S. Pat. No.
4,204,969 to Papay et al.; U.S. Pat. No. 4,954,274 to Zaweski et
al.; U.S. Pat. No. 4,966,720 to DeGonia et al.; and U.S. Pat. No.
3,703,504 to Horodysky, et al.
[0042] Methods for preparing sulfurized olefins, including the
methods disclosed in the aforementioned patents, generally involve
multiple stages. The first stage generally involves the formation
of a material, typically referred to as an "adduct", in which an
olefin is reacted with a sulfur halide, for example, sulfur
monochloride. The adduct is then reacted with a sulfur source to
provide the sulfurized olefin. The quality of a sulfurized olefin
is generally measured by various physical properties, including,
for example, viscosity, sulfur content, halogen content and copper
corrosion test weight loss (CCT).
[0043] U.S. Pat. No. 4,966,720, relates to sulfurized olefins
useful as extreme pressure (EP) additives in lubrication oils and
to a two stage reaction for their preparation. In the first stage,
the reaction temperature between the olefin and sulfur monochloride
is maintained from 0.degree. to 22.degree. C. in order to make a
low molecular weight adduct. In the second stage of the reaction a
sulfur monochloride/aliphatic monoolefin adduct is reacted in a
basic, aqueous alcoholic solution containing sodium sulfide at a
temperature of from about 50.degree. C. up to reflux to form the
sulfurized olefin. Conventional processes for sulfurized olefins
provide products that are readily soluble in Group I base oils.
However, without a compatibilizer, the sulfurized olefins are less
soluble in Group II and Group III base oils.
[0044] Accordingly, a more readily soluble sulfurized olefin for
Group II and Group III base oils may be formed by increasing the
adduct addition rate to the aqueous sodium sulfide solution,
minimizing the reaction time, and eliminating the addition of solid
sulfur during the reaction. The resulting sulfurized olefin product
has a viscosity of no higher than about 5.5 centistokes at
100.degree. C., a sulfur content within the range of from about 40
to about 50% by weight, and is readily soluble in Group II or Group
III base oils. In particular, a viscosity-dependent rate of
addition of the sulfur monochloride/aliphatic monoolefin adduct to
the aqueous sodium sulfide is illustrated by the following table:
TABLE-US-00001 TABLE 1 Adduct Addition Rate Viscosity Sample No.
(min.) at 100.degree. C. 1 25 4.7 2 45 5.21 3 60 6.23 4 75 6.56 5
90 6.91 6 120 7.33 7 135 9.27 8 240 16.25
[0045] According to the above table, adduct addition rates of less
than about 60 minutes may provide sulfurized extreme pressure
agents that have the desired viscosity. An exemplary process for
making a sulfurized extreme pressure agent that is readily soluble
in Group II and Group III base oils is proved by the following
non-limiting example.
[0046] EXAMPLE 1
Adduct Preparation
[0047] Liquid sulfur monochloride (700 grams) is charged into a
suitable reaction flask equipped with a stirrer, thermometer, a
condenser maintained at 5.degree. C., and a sub-surface gas
sparger. Thereafter, gaseous isobutylene is bubbled into the
reaction flask below the surface of the sulfur monochloride liquid
while stirring to bring the temperature up to 20.degree. C. and the
reaction mixture is maintained at that temperature for the entire
reaction. A total of 530 grams of isobutylene is added to the
sulfur monochloride liquid. HCl evolved by the reaction of
isobutylene and sulfur monochloride is removed from the off-gas by
alkaline scrubbing the off-gas. The adduct thus formed is a clear
amber oil that may be used to form sulfurized isobutylene in a
second stage reaction step. The adduct has a specific gravity of
about 1.183.+-.0.05 at 15.6.degree. C.
Preparation of Group II & III Soluble Sulfurized
Isobutvlene
[0048] A reaction flask is charged with 175 grams water, 1/2
dropper of antifoam B, 325 grams of n-propanol, 135 grams of 50 wt.
% aqueous sodium hydroxide, and 410 grams of 36 wt. % aqueous
sodium hydrosulfide. The mixture is stirred at 700 rpm and heated
under a nitrogen atmosphere to about 60.degree. C. at which time,
500 grams of the adduct described above is added subsurface to the
mixture over a 30 minute period while gradually increasing the
reaction temperature until the temperature of the reaction mass
reaches to about 90.degree. C. by the end of the adduct addition
step. Upon completion of the adduct addition step, the alcohol is
stripped from the reaction mixture by heating the reaction mass to
100.degree. C. at atmospheric pressure. Following the alcohol
stripping step, the pressure of the reaction flask is reduced to 23
inches of mercury while allowing the flask to cool to about
70.degree. C. to complete the removal of the alcohol and most of
the water from the reaction mass. Water (300 grams) is added to the
resulting product, the product and water are stirred for 10
minutes, then allowed to settle for 15 minutes. The lower aqueous
brine layer is separated by decanting this layer from the flask and
the organic layer is then vacuum stripped at 28'' mercury at
100.degree. C. for 45 minutes. After filtering the stripped organic
layer through a bed of diatomaceous earth, a clear yellow oil is
obtained. Analysis of product made by the foregoing procedure
typically has a viscosity in the range of 4.0 to 5.5 cSt. at
100.degree. C., a sulfur content of about 44-47 weight percent, a
chlorine content of less than 1 wt. %, and a copper corrosion test
weight loss (CCT) of about 30-80 milligrams per 100 mL of
sample.
Anti-Wear Agents
[0049] For purposes of this disclosure a component which contains
both phosphorus and sulfur in its chemical structure is deemed a
phosphorus-containing antiwear and/or extreme pressure agent rather
than a sulfur-containing antiwear and/or extreme pressure agent.
Suitable phosphorus-containing anti-wear agents which may be used
include oil-soluble amine salts of a phosphoric acid ester, such as
those taught in U.S. Pat. Nos. 5,354,484 and 5,763,372; and
reaction products of dicyclopentadiene and a thiophosphoric
acid.
[0050] The amine salts of a phosphoric acid ester may be prepared
by reacting a phosphoric acid ester with ammonia or a basic
nitrogen compound, such as an amine. The salts may be formed
separately, and then the salt of the phosphoric acid ester may be
added to the lubricating composition.
[0051] The phosphoric acid esters useful in preparing the amine
salts may be characterized by the formula ##STR2## wherein R.sup.1
is hydrogen or a hydrocarbyl group, R.sup.2 is a hydrocarbyl group,
and both X groups are either O or S.
[0052] The hydroxy compound used in the preparation of the
phosphoric acid esters are characterized by the formula ROH wherein
R is a hydrocarbyl group. The hydroxy compound reacted with the
phosphorus compound may comprise a mixture of hydroxy compounds of
the formula ROH wherein the hydrocarbyl group R contains from about
1 to 30 carbon atoms. It is highly desirable, that the amine salt
of the substituted phosphoric acid ester ultimately prepared is
soluble in the lubricating compositions described herein.
Generally, the R group will contain at least 2 carbon atoms,
typically 3 to 30 carbon atoms.
[0053] The R group may be aliphatic or aromatic such as alkyl,
aryl, alkaryl, aralkyl and alicyclic hydrocarbon groups. Examples
of useful hydroxy compounds of the formula ROH includes, for
example, ethyl alcohol, iso-propyl, n-butyl alcohol, amyl alcohol,
hexyl alcohol, 2-ethyl-hexyl alcohol, nonyl alcohol, dodecyl
alcohol, stearyl alcohol, amyl phenol, octyl phenol, nonyl phenol,
methyl cyclohexanol, alkylated naphthol, etc.
[0054] Suitable alcohols, ROH, are aliphatic alcohols and more
particularly, primary aliphatic alcohols containing at least about
4 carbon atoms. Accordingly, examples of the monohydric alcohols
ROH which are useful include, amyl alcohol, 1-octanol, 1-decanol,
1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol, oleyl
alcohol, linoleyl alcohol, linolenyl alcohol, phytol, myricyl
alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl
alcohol and behenyl alcohol. Commercial alcohols (including
mixtures) are contemplated herein.
[0055] The amine salts of the present may be prepared by reaction
of the above-described phosphoric acid esters with at least one
amino compound which may be a primary or secondary amino compound.
The amines which are reacted with the phosphoric acid esters to
form the amine salts are primary hydrocarbyl amines having the
general formula R'NH.sub.2 wherein R' is a hydrocarbyl group
containing up to about 150 carbon atoms and will more often be an
aliphatic hydrocarbyl group containing from about 4 to about 30
carbon atoms.
[0056] In one exemplary embodiment, the hydrocarbyl amines which
are useful in preparing the amine salts are primary hydrocarbyl
amines containing from about 4 to about 30 carbon atoms in the
hydrocarbyl group, and typically from about 8 to about 20 carbon
atoms in the hydrocarbyl group. The hydrocarbyl group may be
saturated or unsaturated. Representative examples of primary
saturated amines are those known as aliphatic primary fatty amines.
Typical fatty amines include alkyl amines such as n-hexylamine,
n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine,
n-pentadecylamine, n-hexadecylamine, n-octadecylamine (stearyl
amine), etc. Unsaturated primary amines include, dodecenylamine,
myristoleylamine, palmitoleylamine, oleylamine and
linoleylamine.
[0057] In another exemplary embodiment, the amine salts are those
derived from tertiary-aliphatic primary amines having at least
about 4 carbon atoms in the alkyl group. For the most part, they
are derived from alkyl amines having a total of less than about 30
carbon atoms in the alkyl group.
[0058] Usually the tertiary aliphatic primary amines are monoamines
represented by the formula ##STR3## wherein R is a hydrocarbyl
group containing from one to about 30 carbon atoms. Such amines are
illustrated by tertiary-butyl amine, tertiary-hexyl primary amine,
1-methyl-1-amino-cyclohexane, tertiary-octyl primary amine,
tertiary-decyl primary amine, tertiary-dodecyl primary amine,
tertiary-tetradecyl primary amine, tertiary-hexadecyl primary
amine, tertiary-octadecyl primary amine, tertiary-tetracosanyl
primary amine, tertiary-octacosanyl primary amine. Mixtures of
amines may also be used.
[0059] The oil-soluble amine salts may be prepared by mixing the
above-described phosphoric acid esters with the above-described
amines at room temperature or above. Generally, mixing at room
temperature for a period of from up to about one hour is
sufficient. The amount of amine reacted with the phosphoric acid
ester to form the salts is at least about one equivalent weight of
the amine (based on nitrogen) per equivalent of phosphoric acid,
and the ratio of equivalents generally is about one.
[0060] Methods for the preparation of such amine salts are well
known and reported in the literature. See for example, U.S. Pat.
Nos. 2,063,629; 2,224,695; 2,447,288; 2,616,905; 3,984,448;
4,431,552; 5,354,484; and PCT International Application Publication
No. WO 87/07638.
[0061] Alternatively, the amine salts may be formed in situ when
the acidic phosphoric acid ester is blended with the
above-described amines when forming a gear oil concentrate or the
formulated gear oil itself. For example, primary hydrocarbyl amines
that function as rust inhibitors may be added to a gear additive
concentrate containing the acidic phosphoric acid ester leading to
the formation of amine salts of phosphoric acid esters. As
described in more detail below, enhanced solubility of the
sulfurized extreme pressure agent is exhibited when the sulfurized
extreme pressure agent is mixed with the additive concentrate or
lubricant formulation subsequent to combining the amine and acid
components for the concentrate or lubricant formulation.
Rust Inhibitors
[0062] Rust inhibitors may typically be included in lubricant
formulations as described herein. Rust inhibitors may be a single
compound or a mixture of compounds having the property of
inhibiting corrosion of ferrous metal surfaces. Such materials
include oil-soluble monocarboxylic acids such as 2-ethylhexanoic
acid, lauric acid, myristic acid, palmitic acid, oleic acid,
linoleic acid, linolenic acid, behenic acid, cerotic acid, etc.,
and oil-soluble polycarboxylic acids including dimer and trimer
acids, such as are produced from tall oil fatty acids, oleic acid,
linoleic acid, or the like.
[0063] Other suitable corrosion inhibitors include alkenylsuccinic
acids in which the alkenyl group contains 10 or more carbon atoms
such as, for example, tetrapropenylsuccinic acid,
tetradecenylsuccinic acid, hexadecenylsuccinic acid, and the like;
long-chain .alpha.,.OMEGA.-dicarboxylic acids in the molecular
weight range of 600 to 3000; and other similar materials.
[0064] Rust inhibitors as described above are commercially
available from various commercial sources, such as, for example,
dimer and trimer acids sold by Cromton Corporation of Middlebury,
Conn.
[0065] Another useful type of acidic corrosion inhibitors are the
half esters of alkenyl succinic acids having 8 to 24 carbon atoms
in the alkenyl group with alcohols such as the polyglycols.
Especially useful rust inhibitors include the primary and secondary
amine compounds taught herein as the amine portion of the salt of a
phosphoric acid ester as well as mixtures of said amines with other
rust inhibitors described above. When an amine salt of a phosphoric
acid ester is used as the phosphorus-containing anti-wear agent, it
may not be necessary to add additional amine-containing rust
inhibitors to the gear oil formulation. The primary and secondary
amines may contribute from 40 to 125 ppm nitrogen (on a
weight/weight basis) to the formulated gear oil, whether they are
classified as a rust inhibitor, part of the anti-wear system or a
combination of both.
Antioxidants
[0066] Antioxidants that may be employed in gear oil formulations
include phenolic compounds and amines. Amounts of up to about 5 wt.
% in the concentrate are generally sufficient. Gear oil lubricants
may include one or more antioxidants, for example, one or more
phenolic antioxidants, hindered phenolic antioxidants, additional
sulfurized olefins, aromatic amine antioxidants, secondary aromatic
amine antioxidants, sulfurized phenolic antioxidants, oil-soluble
copper compounds and mixtures thereof.
[0067] Suitable exemplary compounds include
2,6-di-tert-butylphenol, liquid mixtures of tertiary butylated
phenols, 2,6-di-tert-butyl-4-methylphenol,
4,4'-methylenebis(2,6-di-tert-butylphenol),
2,2'-methylenebis(4-methyl-6-tert-butylphenol), mixed
methylene-bridged polyalkyl phenols,
4,4'-thiobis(2-methyl-6-tert-butylphenol),
N,N'-di-sec-butyl-p-phenylenediamine, 4-isopropylaminodiphenyl
amine, alkylated diphenylamine and phenyl-.alpha.-naphthyl
amine.
[0068] In the class of amine antioxidants, oil-soluble aromatic
secondary amines; aromatic secondary monoamines; and others are
suitable. Aromatic secondary monoamines include diphenylamine,
alkyl diphenylamines containing 1 to 2 alkyl substituents each
having up to about 16 carbon atoms, phenyl-.alpha.-naphthylamine,
alkyl- or aralkylsubstituted phenyl-.alpha.-naphthylamine
containing one or two alkyl or aralkyl groups each having up to
about 16 carbon atoms, alkyl- or aralkyl-substituted
phenyl-.alpha.-naphthylamine containing one or two alkyl or aralkyl
groups each having up to about 16 carbon atoms.
[0069] In the class of phenolic antioxidants, suitable compounds
include ortho-alkylated phenolic compounds, e.g.
2-tert-butylphenol, 2,6-di-tertbutylphenol,
4-methyl-2,6-di-tertbutylphenol, 2,4,6-tri-tertbutylphenol, and
various analogs and homologs or mixtures thereof; one or more
partially sulfurized phenolic compounds as described in U.S. Pat.
No. 6,096,695, and methylene-bridged alkylphenols as described in
U.S. Pat. No. 3,211,652.
[0070] Antioxidants may be optionally included in the fully
formulated final lubricating composition at from about 0.00 to
about 5.00 weight percent, typically from about 0.01 weight % to
about 1.00 weight %.
Defoaming Agents
[0071] Defoaming agents which may be used include silicone oils of
suitable viscosity, glycerol monostearate, polyglycol palmitate,
trialkyl monothiophosphates, esters of sulfonated ricinoleic acid,
benzoylacetone, methyl salicylate, glycerol monooleate, glycerol
dioleate and polyacrylates. Defoamers are generally employed at
concentrations of up to about 1 wt. % in the additive
concentrate.
Demulsifiers
[0072] Typical additives which may be employed as demulsifiers in
gear oils include alkyl benzene sulfonates, polyethylene oxides,
polypropylene oxides, esters of oil soluble acids and the like.
Such additives are generally employed at concentrations of up to
about 3 wt. % in the additive concentrate.
Friction Modifiers
[0073] One or more friction modifiers may also be included to
provide, for example, limited slip performance and enhanced
positraction performance. Friction modifiers typically include such
compounds as fatty amines or ethoxylated fatty amines, aliphatic
fatty acid amides, ethoxylated aliphatic ether amines, aliphatic
carboxylic acids, glycerol esters, aliphatic carboxylic
ester-amides and fatty imidazolines, fatty tertiary amines, wherein
the aliphatic group usually contains above about eight carbon atoms
so as to render the compound suitably oil soluble. Also suitable
are aliphatic substituted succinimides formed by reacting one or
more aliphatic succinic acids or anhydrides with ammonia or other
primary amines.
Seal Swell Agents
[0074] The lubricating oil compositions may further contain from 0
to 20 weight percent of a seal swell agent. Suitable seal swell
agents include hindered polyol esters and oil-soluble diesters. The
diesters include the adipates, azelates, and sebacates of
C.sub.8-C.sub.13 alkanols (or mixtures thereof), and the phthalates
of C.sub.4-C.sub.13 alkanols (or mixtures thereof). Mixtures of two
or more different types of esters (e.g., dialkyl adipates and
dialkyl azelates, etc.) can also be used. Examples of such
materials include the n-octyl, 2-ethylhexyl, isodecyl, and tridecyl
diesters of adipic acid, azelaic acid, and sebacic acid, and the
n-butyl, isobutyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl,
undecyl, dodecyl, and tridecyl diesters of phthalic acid. Specific
examples include di-2-ethylhexyl adipate, di-isooctyl adipate,
(2-ethylhexyl)(isodecyl) adipate, di-2-ethylhexyl sebacate and
di-isodecyl adipate.
[0075] Although the additive components are described occasionally
with reference to a function, that function may be one of other
functions served by the same component and should not be construed
as a mandatory limiting function.
Diluent Oil
[0076] The additive concentrates described herein may contain a
suitable diluent, typically an oleaginous diluent of suitable
viscosity. Such diluent may be derived from natural or synthetic
sources. Among the mineral (hydrocarbonaceous) oils are paraffin
base, naphthenic base, asphaltic base and mixed base oils. Typical
synthetic base oils include polyolefin oils (especially
hydrogenated .alpha.-olefin oligomers), alkylated aromatic,
polyalkylene oxides, aromatic ethers, and carboxylate esters
(especially diester oils), among others. Blends of natural and
synthetic oils can also be used. The diluents may be light
hydrocarbon base oils, selected from both natural and synthetic
base oils. Generally the diluent oil will have a viscosity in the
range of 13 to 35 centistokes at 40.degree. C.
[0077] For certain applications, pour point depressants may be
added to the gear oil formulation. If present, the gear oil
compositions typically can contain up to 5 wt. % of the pour point
depressant.
[0078] The compositions of the disclosure may be top treated to
achieve multi-functional performance (i.e., both automotive and
industrial applications).
[0079] The multi-grade gear oils described above may be suitable
for use in automotive gear applications such as final drives,
power-dividers or axles in light and heavy-duty vehicles or manual
transmissions in a truck or heavy equipment and industrial gear
applications.
[0080] In the following illustrative examples gear oil additive
packages were made by a conventional process and by a process as
described in the disclosure. The gear oil additive packages
contained the following components in the amounts indicated.
TABLE-US-00002 TABLE 1 Gear Oil Additive Components Component Wt. %
Tolytrizole 0.0-0.3 Primary amine 2.0-7.0 Acid phosphate 5.0-15.0
Polyacrylate antifoam agent 1.0-5.0 Mineral oil diluent 5.0-10.0
Carboxylic acid rust inhibitor 0.0-2.0 Thiadiazole corrosion
inhibitor 2.0-5.0 Sulfurized isobutylene 50.0-95.0
EXAMPLE 2
[0081] In this example, the order of mixing the foregoing
components and amounts of each component are given in Table 2. This
example represents a conventional method for making additive
concentrates for use in lubricant formulations. TABLE-US-00003
TABLE 2 Order of Addition Component Wt. % 1 Sulfurized isobutylene
0.0-20.0 2 Primary amine 2.0-7.0 3 Tolytrizole 0.0-0.3 4 Mineral
oil diluent 5.0-10.0 5 Thiadiazole corrosion inhibitor 2.0-5.0 6
Sulfurized isobutylene 0.0-95.0 7 Acid phosphate 5.0-15.0 8
Polyacrylate antifoam agent 1.0-5.0 9 Carboxylic acid rust
inhibitor 0.0-2.0
EXAMPLE 3
[0082] In following example, the order of addition of the foregoing
components and amounts of each component are given in Table 3. This
example represents an exemplary embodiment of the disclosure, but
is not intended to limit the disclosure. TABLE-US-00004 TABLE 3
Order of Addition Component Wt. % 1 Tolytrizole 0.0-0.3 2 Primary
amine 2.0-7.0 3 Thiadiazole corrosion inhibitor 2.0-5.0 4 Acid
phosphate 5.0-15.0 5 Polyacrylate antifoam agent 1.0-5.0 6 Mineral
oil diluent 5.0-10.0 7 Carboxylic acid rust inhibitor 0.0-2.0 8
Sulfurized isobutylene 50.0-95.0
[0083] In Table 2, the sulfurized isobutylene was added in the
first and sixth steps for preparing the additive package. In Table
3, the sulfurized isobutylene (SIB) was added in the last step of
the mixture process for the additive package. Each of the additive
packages prepared in Tables 2 and 3 were combined with a
polyalphaolefin-based gear oil and with a Group II base oil to
provide a lubricating oil composition containing about 4 percent by
weight of the additive package. The polyalphaolefin-based gear oil
had a base NTU of 0.3 and the Group II base oil had a base NTU of
2. The turbidity of each of the lubricating oil compositions made
from the additive packages are provided in the following table.
TABLE-US-00005 TABLE 4 Table 2 Procedure (NTU) Table 3 Procedure
(NTU) Sample Low Low No. Base Oil Std. SIB Vis. SIB Std. SIB Vis.
SIB 1 PAO >2000 -- -- -- 2 PAO -- >700 -- -- 3 PAO -- -- --
<5 4 PAO -- -- 123 -- 5 Group II 205 -- -- -- 6 Group II -- 2 --
-- 7 Group II -- -- 2 -- 8 Group II -- -- -- 2
[0084] As shown by the foregoing table, there is an unexpected and
dramatic decrease in the turbidity or haziness of lubricant
formulations made containing the additive package formulated by the
procedure of Table 3 (Sample Nos. 3 and 4 compared to Sample No. 1)
wherein the sulfurized isobutylene is added in the last stage of
the process for making the additive package. Similar result may be
obtained by combining the acidic and basic or amine components for
a lubricant or additive package in any step prior to adding
sulfurized extreme pressure agents to the package or lubricant when
the lubricant is formulated with at least one substantially
non-polar base oil. Thus is it not critical that the sulfirized
extreme pressure agent be added in the last step for making the
additive or lubricant.
[0085] Furthermore, a significant decrease in turbidity may be
obtained in PAO or in a Group II base oil by using a low viscosity
(soluble) SIB as shown by Sample Nos. 2 and 3 compared to Sample
No. 1, and Sample Nos. 6 and 8 compared to Sample No. 5. The
results indicated that the particular SIB used in the formulation
is less important in a Group II base oil than in a more non-polar
base oil such as PAO when the Table 3 procedure is used as shown by
comparing Sample Nos. 7 and 8. Accordingly, a combination of low
viscosity SIB and/or the addition of SIB to previously combined
acid and basic or amine components are particularly useful for
reducing the turbidity of formulations including substantially
non-polar base oils such as, but not limited to, Group II, Group
III, and Group IV base oils.
[0086] At numerous places throughout this specification, reference
has been made to a number of U.S. Patents. All such cited documents
are expressly incorporated in full into this disclosure as if fully
set forth herein.
[0087] The foregoing embodiments are susceptible to considerable
variation in its practice. Accordingly, the embodiments are not
intended to be limited to the specific exemplifications set forth
hereinabove. Rather, the foregoing embodiments are within the
spirit and scope of the appended claims, including the equivalents
thereof available as a matter of law.
[0088] The patentees do not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part hereof under
the doctrine of equivalents.
* * * * *