U.S. patent application number 13/444208 was filed with the patent office on 2012-10-18 for lubricant blends with pao-based dispersants.
This patent application is currently assigned to EXXONMOBIL RESEARCH AND ENGINEERING COMPANY. Invention is credited to Douglas E. Deckman, Liepao Oscar Farng, Ernestine W. Hill, Beth A. Winsett, Margaret May-Som Wu.
Application Number | 20120264665 13/444208 |
Document ID | / |
Family ID | 47006824 |
Filed Date | 2012-10-18 |
United States Patent
Application |
20120264665 |
Kind Code |
A1 |
Wu; Margaret May-Som ; et
al. |
October 18, 2012 |
LUBRICANT BLENDS WITH PAO-BASED DISPERSANTS
Abstract
Provided is a lubricant blend including one or more lubricant
base stocks and one or more dispersants. The dispersant is chosen
from a polyalphaolefin succinimide, a polyalphaolefin succinamide,
a polyalphaolefin acid ester, a polyalphaolefin oxazoline, a
polyalphaolefin imidazoline, a polyalphaolefin succinamide
imidazoline, and combinations thereof. The one or more dispersants
are present at 2 to 20 wt % based on the total weight of the blend.
The one or more dispersants and the one or more lubricant base
stocks are together present at 8 wt % or more of the total weight
of the blend. Provided is also a process for making the lubricant
blend and a method for the service life of a lubricant.
Inventors: |
Wu; Margaret May-Som;
(Skillman, NJ) ; Winsett; Beth A.; (Houston,
TX) ; Farng; Liepao Oscar; (Lawrenceville, NJ)
; Deckman; Douglas E.; (Mullica Hill, NJ) ; Hill;
Ernestine W.; (New Albany, OH) |
Assignee: |
EXXONMOBIL RESEARCH AND ENGINEERING
COMPANY
Annandale
NJ
|
Family ID: |
47006824 |
Appl. No.: |
13/444208 |
Filed: |
April 11, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61474912 |
Apr 13, 2011 |
|
|
|
Current U.S.
Class: |
508/277 ;
508/269; 508/287; 508/463; 508/551 |
Current CPC
Class: |
C10M 169/04 20130101;
C10N 2030/04 20130101; C10M 2207/34 20130101; C10M 133/56 20130101;
C10M 2215/28 20130101; C10M 129/95 20130101; C10M 2215/30 20130101;
C10M 133/58 20130101 |
Class at
Publication: |
508/277 ;
508/287; 508/551; 508/463; 508/269 |
International
Class: |
C10M 149/22 20060101
C10M149/22; C10M 145/22 20060101 C10M145/22 |
Claims
1. A lubricant blend comprising one or more lubricant base stocks
and a dispersant chosen from: a polyalphaolefin succinimide, a
polyalphaolefin succinamide, a polyalphaolefin acid ester, a
polyalphaolefin oxazoline, a polyalphaolefin imidazoline, a
polyalphaolefin succinamide imidazoline, and combinations thereof,
wherein the one or more dispersants are present at 2 to 20 wt %
based on the total weight of the blend, and wherein the one or more
dispersants and the one or more lubricant base stocks are together
present at 85 wt % or more of the total weight of the blend.
2. The blend of claim 1, wherein the one or more dispersants and
the one or more lubricant base stocks are together present at 90 wt
% or more of the total weight of the blend.
3. The blend of claim 1, wherein the one or more dispersants and
the one or more lubricant base stocks are together present at 95 wt
% or more of the total weight of the blend.
4. The blend of claim 1, wherein the one or more dispersants are
present at 5 to 15 wt % based on the total weight of the blend.
5. The blend of claim 1, wherein the one or more dispersants are
present at 5 to 10 wt % based on the total weight of the blend.
6. The blend of claim 1, wherein the one or more lubricant base
stocks is chosen from a Group I, Group II, Group II+, Group III,
Group III+, Group IV, Group V, and combinations thereof.
7. The blend of claim 1, wherein the one or more lubricant base
stocks includes a Group III+ base stock.
8. The blend of claim 1, wherein the dispersant exhibits a
kinematic viscosity at 100.degree. C. of less than 700 cS, a
kinematic viscosity at 40.degree. C. of less than 50,000 cS, and a
viscosity index of greater than 135.
9. The blend of claim 1, wherein the dispersant diluted with up to
35 wt % mineral oil exhibits a kinematic viscosity at 100.degree.
C. of less than 200 cS, a kinematic viscosity at 40.degree. C. of
less than 10,000 cS, and a viscosity index of greater than 100,
from 100 to 200.
10. The blend of claim 1, wherein the dispersant is a
polyalphaolefin succinimide.
11. The blend of claim 1, wherein the dispersant is a
polyalphaolefin succinamide.
12. The blend of claim 1, wherein the dispersant is a
polyalphaolefin acid ester.
13. The blend of claim 1, wherein the dispersant is a
polyalphaolefin oxazoline.
14. The blend of claim 1, wherein the dispersant is a
polyalphaolefin imidazoline.
15. The blend of claim 1, wherein the dispersant is a
polyalphaolefin succinamide.
16. A process for making a lubricant blend comprising: admixing an
amount of one or more lubricant base stocks and an amount of a
dispersant chosen from: a polyalphaolefin succinimide, a
polyalphaolefin succinamide, a polyalphaolefin acid ester, a
polyalphaolefin oxazoline, a polyalphaolefin imidazoline, a
polyalphaolefin succinamide imidazoline, and combinations thereof,
wherein the one or more dispersants are present at 2 to 20 wt %
based on the total weight of the blend, and wherein the one or more
dispersants and the one or more lubricant base stocks are together
present at 85 wt % or more of the total weight of the blend.
17. The process of claim 16, wherein the one or more lubricant base
stocks is chosen from a Group I, Group II, Group II+, Group III,
Group III+, Group IV, Group V, and combinations thereof.
18. The process of claim 16, wherein the dispersant exhibits a
kinematic viscosity at 100.degree. C. of less than 700 cS, a
kinematic viscosity at 40.degree. C. of less than 50,000 cS, and a
viscosity index of greater than 135.
19. The process of claim 16, wherein the dispersant diluted with up
to 35 wt % mineral oil exhibits a kinematic viscosity at
100.degree. C. of less than 200 cS, a kinematic viscosity at
40.degree. C. of less than 10,000 cS, and a viscosity index of
greater than 100, from 100 to 200.
20. A method for lengthening the service life of a lubricant
formulation comprising: admixing with one or more lubricant base
stocks an amount of a dispersant chosen from: a polyalphaolefin
succinimide, a polyalphaolefin succinamide, a polyalphaolefin acid
ester, a polyalphaolefin oxazoline, a polyalphaolefin imidazoline,
a polyalphaolefin succinamide imidazoline, and combinations
thereof, and utilizing the lubricant formulation as an oil or
grease in a device or apparatus requiring lubrication of moving
and/or interacting mechanical parts, components, or surfaces,
wherein the one or more dispersants are present at 2 to 20 wt %
based on the total weight of the blend, and wherein the one or more
dispersants and the one or more lubricant base stocks are together
present at 85 wt % or more of the total weight of the blend.
21. The method of claim 20, wherein the one or more lubricant base
stocks is chosen from a Group I, Group II, Group II+, Group III,
Group III+, Group IV, Group V, and combinations thereof.
22. The method of claim 20, wherein the dispersant exhibits a
kinematic viscosity at 100.degree. C. of less than 700 cS, a
kinematic viscosity at 40.degree. C. of less than 50,000 cS, and a
viscosity index of greater than 135.
23. The method of claim 20, wherein the dispersant diluted with up
to 35 wt % mineral oil exhibits a kinematic viscosity at
100.degree. C. of less than 200 cS, a kinematic viscosity at
40.degree. C. of less than 10,000 cS, and a viscosity index of
greater than 100, from 100 to 200.
24. A lubricant formulation prepared by the process comprising:
admixing with one or more lubricant base stocks an amount of a
dispersant chosen from: a polyalphaolefin succinimide prepared by
reacting an unhydrogenated polyalphaolefin with maleic anhydride to
form a polyalphaolefin anhydride followed by reacting the
polyalphaolefin anhydride with a polyamine, a polyalphaolefin
succinamide prepared by reacting an unhydrogenated polyalphaolefin
with maleic anhydride to form a polyalphaolefin anhydride followed
by reacting the polyalphaolefin anhydride with a polyamine, a
polyalphaolefin acid ester prepared by reacting an unhydrogenated
polyalphaolefin with maleic anhydride to form a polyalphaolefin
anhydride followed by reacting the polyalphaolefin anhydride with a
polyamine, a polyalphaolefin oxazoline prepared by reacting an
unhydrogenated polyalphaolefin with maleic anhydride to form a
polyalphaolefin anhydride followed by reacting the polyalphaolefin
anhydride with an aminoalcohol, a polyalphaolefin amide-imidazoline
prepared by reacting a polyalphaolefin succinamide with a
polyamine, and combinations of two or more of the foregoing,
wherein the one or more dispersants are present at 2 to 20 wt %
based on the total weight of the blend, and wherein the one or more
dispersants and the one or more lubricant base stocks are together
present at 85 wt % or more of the total weight of the blend.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional application that claims priority
to U.S. Provisional Patent Application No. 61/474,912 filed on Apr.
13, 2011, herein incorporated by reference in its entirety.
FIELD
[0002] The present disclosure relates to lubricant blends including
dispersants. The present disclosure further relates to lubricant
blends exhibiting desirable viscosity properties.
BACKGROUND
[0003] Dispersants have been employed in lubricant and fuel
formulations to provide protection against and to stabilize dirt
and sludge that accumulate in the formulations during ordinary use.
Dispersants typically have hydrophilic heads and hydrophobic tails
and exhibit the properties of surfactants. The hydrophilic heads
have an affinity for dirt and sludge, while the hydrophobic tails
have an affinity for the base stocks of the lubricant and fuel
formulations.
[0004] Conventional dispersants most often used in lubricant or
fuel formulations have been the type prepared by functionalizing
polyisobutylene (PIB) of varying molecular weights with maleic
anhydride followed by reaction with polyamines [Lubricant
additives, Chemistry and Applications, by L. R. Rudnick, 2003
Marcel Dekker, Inc. New York, NJ 10016]. These dispersants work
well for conventional lubricant and fuel formulations. In many
automotive engine lubricant formulations, 3 to 10 wt % of
dispersant has typically been used, the highest amount of all
additives used in such formulations.
[0005] New lubricants are needed to meet higher automobile fuel
economy standards, longer oil drain intervals, and greater
operating severity. This need may require the use of even higher
levels of dispersants and/or lower lubricant base stock viscosity.
The use of higher levels of PIB-based dispersants, however, may
significantly increase the viscosity of lubricant formulations and
render it difficult to attain lower motor oil viscosity grades,
e.g., 0W20 and 0W30. Lower viscosity grades for motor oil are
particularly important in meeting fuel economy guidelines.
[0006] An alternative to increasing dispersant levels is to use
lower viscosity base stocks. However, the use of such lower
viscosity base stocks can result in higher volatility (loss of oil)
and reduced lubricant oil film and wear protection on internal
engine surfaces.
[0007] Thus, there is a need for a dispersant that provides
lubricant formulations with effective protection against the
effects of dirt and sludge accumulation. There is also a need for a
dispersant that provides lubricant formulations with such
protection without significant increase in a required amount of
dispersant and/or formulation viscosity.
SUMMARY
[0008] According to the present disclosure, there is provided a
lubricant blend. The blend has one or more lubricant base stocks
and a dispersant. The dispersant is selected from the group
consisting of a polyalphaolefin succinimide, a polyalphaolefin
succinamide, a polyalphaolefin acid ester, a polyalphaolefin
oxazoline, a polyalphaolefin imidazoline, a polyalphaolefin
succinamide imidazoline, and combinations thereof. The one or more
dispersants are present at 2 to 20 wt % based on the total weight
of the blend. The one or more dispersants and the one or more
lubricant base stocks are together present at 85 wt % or more of
the total weight of the blend.
[0009] Further according to the present disclosure, there is
provided a process for making a lubricant blend. The process has
the step of admixing an amount of the one or more lubricant base
stocks and the amount of the dispersant described above in the
proportions described above.
[0010] Still further according to the present disclosure, there is
provided a method for lengthening the service life of a lubricant.
The method has the steps of admixing with an amount of the one or
more lubricant base stocks and the amount of the dispersant
described above in the proportions described above, and utilizing
the lubricant formulation as an oil or grease in a device or
apparatus requiring lubrication of moving and/or interacting
mechanical parts, components, or surfaces.
[0011] According to the present disclosure, there is provided a
lubricant blend provided by a process. The blend is produced by
admixing one or more lubricant base stocks with a dispersant
produced by a process of reacting (A) a polyalphaolefin with a
polyamine to yield a polyalphaolefin succinimide and/or a
polyalphaolefin succinamide and/or polyalphaolefin
succinamide-imidazoline, or (B) a polyalphaolefin with an alcohol
or polyol to yield a succinic acid ester or (C) a polyalphaolefin
with an amino alcohol to yield an polyalphaolefin amide-oxazoline.
The dispersant is 2 to 20 wt % based on the total weight of the
blend. The dispersant and the one or more lubricant base stocks are
together present at 85 wt % or more of the total weight of the
blend.
DETAILED DESCRIPTION
[0012] All numerical values within the detailed description and the
claims herein are modified by "about" or "approximately" the
indicated value, and take into account experimental error and
variations that would be expected by a person having ordinary skill
in the art.
[0013] The polyalphaolefin succinimide (PAO-imide), polyalphaolefin
succinamide (PAO-amide), and/or polyalphaolefin succinic acid ester
(PAO-ester), polyalphaolefin oxazoline, and polyalphaolefin
imidazoline dispersant disclosed herein provides lubricant
formulations with effective and enhanced protection against dirt
and sludge such that automobile oil drain intervals can be
lengthened and severe operation maintained. The dispersant provides
enhanced protection without need for substantial increase in amount
employed. The dispersant provides enhanced stabilization of dirt
and sludge without substantial increase in viscosity, including
without substantial increase in kinematic viscosity at 40.degree.
C. and 100.degree. C. The dispersant provides improved low
temperature properties, such as improvement of CCS performance at
-15.degree. C. to -40.degree. C. and improvement of low temperature
kinematic viscosities at less than -15.degree. C.
[0014] The dispersants can be synthesized to have similar amounts
of nitrogen content and similar degree of dispersancy as
conventional PIB-imide, PIB-amide and PIB-ester dispersants. The
dispersants provide an easier and broader formulation window to
reach fuel-efficient viscosity grades and/or the use of more
conventional base stocks of higher viscosity and provide in better
overall performance. PAO also reacts faster with maleic anhydride
than does PIB and affords a greater degree of
functionalization.
[0015] Polyalphaolefins (PAO) useful as feedstock in forming the
dispersants are those derived from oligomerization or
polymerization of ethylene, propylene, and .alpha.-olefins.
Suitable .alpha.-olefins include 1-butene, 1-pentene, 1-hexene,
1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene,
1-tetradecene, and 1-octadecene. Feedstocks containing a mixture of
two or more of the foregoing monomers as well as other hydrocarbons
are typically employed when manufacturing PAOs commercially. The
PAO may take the form of dimers, trimers, tetramers, polymers, and
the like.
[0016] The PAO used to prepare PAO-based dispersants may have a
M.sub.W (weight-average molecular weight) of 450 to 24,000,
preferably 600 to 20,000, preferably 600 to 18,000, preferably 600
to 16,000, preferably 600 to 14,000, preferably 600 to 7,500, and
most preferably 600 to 4,000. The PAO may have a M.sub.n
(number-average molecular weight) of 280 to 12,000, preferably 400
to 10,000, preferably 500 to 9,000, preferably 500 to 7,500,
preferably 500 to 6,000, preferably 500 to 4,400, preferably 400 to
1,000, and most preferably 400 to 800. The PAO may have a
M.sub.W/M.sub.n or molecular weight distribution of 1.1 to 3.0,
preferably 1.2 to 2.5, and most preferably 1.3 to 2.2. The
molecular weights of the PAO were measured by a gel permeation
chromatograph equipped with universal column and calibrated with
commercial polystyrene GPC standard of very narrow molecular weight
distribution. The PAO may have a 100.degree. C. kinematic viscosity
measured of 2 cSt to 1,000 cSt, preferably 3 cSt to 800 cSt,
preferably 4 cSt to 600 cSt, preferably 5 cSt to 450 cSt,
preferably 5 cSt to 300 cSt, preferably 5 cSt to 150 cSt,
preferably 4 cSt to 40 cSt, and preferably 4 cSt to 20 cSt. The PAO
may have a 40.degree. C. kinematic viscosity measured of 4 cSt to
12,000 cSt, preferably 10 cSt to 1,000 cSt, preferably 20 cSt to
8,000 cSt, preferably 20 cSt to 6,000 cSt, preferably 20 cSt to
4,000 cSt, preferably 20 cSt to 2,000 cSt, and most preferably 4
cSt to 250 cSt. The PAO may have a viscosity index of 70 to 350,
preferably 80 to 300, preferably above 100, preferably above 150,
preferably above 170, preferably above 200, and most preferably 120
to 300. The PAO may have a pour point as measured by ASTM D97
method or equivalent method of less than 0.degree. C., or
preferably less than -15.degree. C., or less than -25.degree. C.,
or less than -35.degree. C., or less than -40.degree. C. Usually,
it is preferred to use PAO that has low pour point and high VI as
starting material for the synthesis of dispersant to ensure a final
product with optimum viscometric properties.
[0017] The PAO is preferably prepared by oligomerization or
polymerization in the presence of an activated metallocene
catalyst. Manufacture of PAO in the presence of metallocene
catalysts is disclosed, for example, in WO 2007/011462 A1, WO
2007/011459 A1, and WO 2007/011973 A1, all of which are
incorporated herein by reference.
[0018] The PAO can be prepared from any one or two or more
alpha-olefins containing 3 to 24 carbons. When a single
alpha-olefin is used as a feed, it is preferred to select a feed
olefin from C.sub.3 to C.sub.18 linear alpha-olefin (LAO), or
preferably from C.sub.4 to C.sub.16-LAO, or preferably from C.sub.6
to C.sub.14-LAO, or preferably from C.sub.6 to C.sub.12-LAO, or
preferably from C.sub.6 to C.sub.10-LAO, or preferably C.sub.8 to
C.sub.12-LAO, or preferably C.sub.6 or C.sub.8 or C.sub.10 LAO.
When a mixture of alpha-olefins containing two or more linear
alpha-olefins is used as the feed, the mixed alpha-olefins can be
selected from any C.sub.3 to C.sub.24-LAO, or preferably C.sub.4 to
C.sub.20-LAO, or preferably C.sub.6 to C.sub.20-LAO, or preferably
C.sub.6 to C.sub.18-LAO, or preferably C.sub.4 to C.sub.18-LAO, or
preferably C.sub.6 to C.sub.14-LAO, or preferably C.sub.6 to
C.sub.12-LAO, or most preferably C.sub.8 to C.sub.12-LAO. When a
mixture of alpha-olefins containing two or more linear
alpha-olefins is used as the feed, the preferred composition of the
feed LAOs should have an average carbon length of greater than 4.
For example, a feed containing 50 wt % 1-butene and 50 wt %
I-pentene has an average carbon length of 4.4. A feed containing 50
wt % 1-butene and 50 wt % 1-hexene has an average carbon length of
4.8. A feed containing 50 wt % 1-butene and 50 wt % 1-octene has an
average carbon length of 5.3. A feed containing 50 wt % 1-butene
and 50 wt % 1-decene has an average carbon length of 5.7. A feed
containing 50 wt % 1-butene and 50 wt % 1-dodecene has an average
carbon length of 6. A feed containing 50 wt % 1-butene and 50 wt %
1-tetradecene has an average carbon length of 6.2. A feed
containing 50 wt % 1-hexene and 50 wt % 1-octene has an average
carbon length of 6.9. A feed containing 33.3 wt % 1-hexene and 66.7
wt % 1-dodecene has an average carbon length of 9.0. A feed
containing 33.3 wt % 1-hexene, 33.3 wt % 1-octene, and 33.3 wt %
1-dodecene has an average carbon length of 8. Other combinations of
mixed linear alpha-olefins, such as C.sub.6/C.sub.14,
C.sub.6/C.sub.8/C.sub.10/C.sub.12, C.sub.6/C .sub.10/C.sub.14,
C.sub.8/C.sub.10/C.sub.12, C.sub.8/C.sub.14, and the like can also
be used. The choice of linear alpha-olefins typically depends on
availability. Usually, it is most preferred to choose the linear
alpha-olefins mixture such that the average carbon number of the
mixture is greater than 4, or alternatively greater than 4.5,
alternatively greater than 5, alternatively greater than 5.5,
alternatively greater than 6, and most alternatively greater than
6.5. In all cases, it is also preferred to have the average carbon
length no larger than 14, preferably no larger than 12, preferably
no larger than 11, preferably no larger than 10.5, and most
preferably no larger than 10. Usually, the larger the average
carbon length of the feed olefins, the higher VI for the liquid PAO
product. Higher VI is usually more beneficial. However, when the
average carbon number of the feed olefins is much above 11 or 12,
the long chain hydrocarbon portion of the PAO may cause severe low
temperature viscosity increase due to partial gel formation or
partial crystallization, which is undesirable. Therefore, a
preferred average carbon length for the feed olefins is between 4.5
and 11.5 and most preferably 4.5 to 10.5.
[0019] In a preferred process, feed olefins, usually
linear-alpha-olefins, are polymerized in the presence of activated
metallocene catalysts, which results in a PAO containing only
un-isomerized branches. More preferred PAO usually contains
branches of two or more carbons. Examples of the branches are
ethyl, propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl,
n-nonyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, or mixture
of any of them. More preferred branches are ethyl, n-butyl,
n-hexyl, n-octyl, n-decyl, n-tetradecyl, or mixture of them.
Dispersants derived from these PAO with linear branches are more
desirable than the dispersants prepared from polyolefins prepared
from branched olefins, such as iso-butylene.
[0020] The PAO is reacted with maleic anhydride (MA) to form the
polyalphaolefin succinic anhydride (PAO-SA) and subsequently the
anhydride is reacted with one or more of polyamines, aminoalcohols,
and alcohols/polyols to form polyalphaolefin succinimide,
polyalphaolefin succinamide, polyalphaolefin succinic acid ester,
polyalphaolefin oxazoline, polyalphaolefin imidazoline,
polyalphaolefin-succinamide-imidazoline, and mixtures thereof as
represented by the following reaction sequences:
PAO (unhydrogenated)+maleic anhydride.fwdarw.PAO-SA (succinic
anhydride)
PAO-SA+polyamine.fwdarw.PAO-imide and PAO-amide and
PAO-amide-imidazoline
PAO-SA+alcohol/polyol.fwdarw.PAO-acid ester
PAO-SA+amino alcohol.fwdarw.PAO-amide-oxazoline
[0021] Some reaction products are depicted below:
##STR00001##
wherein R.sub.1 is a branched C.sub.20-C.sub.200 alkyl or alkenyl
group derived from poly alpha-olefins; R.sub.2 and R.sub.3 are
independently a C.sub.1-C.sub.10 branched or straight chained
alkylene group; n is an integer from 1 to 10; R.sub.5 and R.sub.6
are H or R.sub.5 and R.sub.6 together along with the N atom bound
thereto form the group:
##STR00002##
wherein R.sub.7 is a branched or straight-chained
C.sub.20-C.sub.200 alkyl or alkenyl group derived from
polyalphaolefins; wherein the N atom bound to the R.sub.2 and
R.sub.3 groups above is optionally substituted in one or more
places with the following group:
--R.sub.8--R.sub.9
wherein R.sub.8 is a C.sub.1-C.sub.10 branched or straight chained
alkylene group; and R.sub.9 is NH.sub.2 or
##STR00003##
[0022] wherein R.sub.10 is a branched or straight-chained
C.sub.20-C.sub.200 alkyl or alkenyl group; and wherein the
R.sub.2--NH--R.sub.3 group is optionally interrupted in one or more
places by a heterocyclic or homocyclic cycloalkyl group, and
wherein one or more of R.sub.1, R.sub.7 and R.sub.10 groups is a
substituted or unsubstituted poly-alpha-olefin. For example, one or
more of R.sub.1, R.sub.7 and R.sub.10 can be independently selected
from poly(1-pentene) (POP), poly(1-decene) (POD), or other
poly-alpha-olefins in which each repeat unit contains 5-18 carbon
atoms, i.e., poly(1-pentene), poly(1-hexene), poly(1-heptene),
poly(1-octene), poly(1-nonene), poly(1-undecene), poly(1-dodecene),
or poly-alpha-olefins prepared from mixture of C.sub.3 to C.sub.24
linear-alpha-olefins. The poly-alpha-olefins can have from 20 to
200 carbon atoms in the polymer.
[0023] Based on the bonding environment, the nitrogen atom in the
above-mentioned mixtures or combinations of compounds can have any
of several different types of bonding. The types of bonding are
illustrated in the following structures:
##STR00004##
Primary amine (two hydrogen atoms bonded with nitrogen atom)
##STR00005##
Secondary amine (one hydrogen atom bonded with nitrogen atom).
R.sub.a and R.sub.b can be the same or different.
##STR00006##
Tertiary amine (no hydrogen atom bonded with nitrogen atom.
R.sub.a, R.sub.b and R.sub.c can be the same or can be complete
different.
##STR00007##
Imide (nitrogen atom bonded in the succinyl anhydride ring, ring is
closed). R.sub.a and R.sub.b can be the same or can be
different.
##STR00008##
Secondary Amide (nitrogen atom bonded with a carbonyl group and
have one hydrogen atom bonded to nitrogen atom). R.sub.a and
R.sub.b can be the same or can be different.
##STR00009##
Tertiary Amide (nitrogen atom bonded with a carbonyl group and have
no hydrogen atom bonded to nitrogen atom. R.sub.a, R.sub.b and
R.sub.c can be the same or different.
[0024] In some embodiments, at least one of R.sub.1, R.sub.7 and
R.sub.10, as defined above, is poly-1-decene (POD). In one
embodiment, the additive is selected from
##STR00010##
[0025] It will be understood by persons of ordinary skill in the
art that various chemical structures as shown above shall have very
different ratios of their functional groups (i.e. amine
(primary-secondary/tertiary)/amide/imide). For example, the amine
to imide ratio in structure (I) is 3:2 while the ratio in structure
(II) is 4:1. To be more specific, although the amine to imide ratio
is the same in structure (III) as in structure (II), the tertiary
amine to primary amine ratio is 1:1 in structure (III) but at 0:4
in structure (II). The relative amine/amide/imide ratios can be
important as their performance levels could be very different.
[0026] The PAO-MA maleination reaction is carried out at a
temperature of 120 to 280.degree. C., preferably 150.degree. C. to
250.degree. C., and most preferably 170.degree. C. to 220.degree.
C. The reaction can be carried out at a pressure of 2 psi to 100
psi, preferably sub-atmospheric pressure to 50 psi, and most
preferably atmospheric pressure to 30 psi. The reaction is carried
out (reaction time) for 1 hour to 48 hours, preferably 2 hours to
24 hours, and most preferably 4 hours to 12 hours. Analogous
procedures for maleination of polyisobutylene (PIB) are disclosed,
for example, in U.S. Pat. Nos. 6,051,537, 6,355,074, 6,355,603,
3,284,410 and 3,948,800. Excess molar quantity of maleic anhydride
can be used to increase conversion rates. However, since
unhydrogenated PAO has higher reactivity than typical
polyisobutylene, a lower reaction temperature can be employed. For
example, most PIB-maleic anhydride reaction temperature is
190.degree. C. or more, while in the case of PAO-maleic anhydride,
reasonable conversion can be achieved at 140.degree. C. or
more.
[0027] The synthesis of PAO-succinic anhydride can be carried out
through a thermal process (without catalyst) at relatively high
temperature or a chlorine catalyzed process at much lower reaction
temperature. A typical set of process conditions can be described
by the batch reactor conditions as follows. A CSTR reactor equipped
with cooling tower, mechanical agitator, gas inlet and outlet can
be employed. The system was flushed with nitrogen to avoid
oxidation and the mixture (PAO and maleic anhydride) was heated to
110.degree. C., then to 140.degree. C. with vigorous stirring for
an adequate amount of reaction time. The unreacted maleic anhydride
was stripped by heating under nitrogen stream at 190.degree. C. The
residue is the desired polyalphaolefin-substituted succinic
anhydride having an appropriate saponification equivalent number as
determined by ASTM procedure D94. If chlorine process is chosen,
excess amount of gaseous chlorine is added beneath the surface to
achieve the best catalytic effect and the reaction temperature can
be as low as 130.degree. C. to 140.degree. C. range. The subsequent
reaction from polyalphaolefin succinic anhydride to polyalphaolefin
succinimide and/or succinamide can be carried out with a commercial
mixture of alkylene polyamines having from 3 to 10 nitrogen atoms
per molecule and the presence of some mineral oil to reduce
viscosity. The reaction mixture is heated to 135.degree. C. to
155.degree. C. and stripped by blowing with nitrogen. The reaction
mixture is filtered to yield the filtrate as an oil solution of the
desired product. Polyalphaolefin amide imidazoline can be prepared
by reacting a polyalphaolefin succinamide with a stoichiometric
excess of a polyamine and extra reaction time.
[0028] It is advantageous to use the PAO described above for the
synthesis of the dispersant. These PAOs usually have higher
reactivity because the olefin composition is rich in vinylidene or
1,2-disubstituted olefins and low in tri- or tetra-substituted
olefins. Vinylidene and 1,2-disubstituted olefins have higher
reactivity with maleic anhydride. Typically, the total amount of
vinylidene and 1,2-di-substituted olefin content is great than 50%
of the total olefins, preferably greater than 60%, preferably
greater than 70%, preferably greater than 80%, preferably greater
than 90%. The most preferred range is from 60 to 85%. The PAOs
produced in this method has less impurities than many of the
traditional polymeric olefins such as poly-isobutylene (PIB). Some
of the impurities, such as fluorides or aluminum, may act as
inhibitor for the reaction with maleic anhydride. The PAOs produced
in this method have much better thermal stability than PIB. Thus,
it will not decompose under high reaction temperatures usually
required for maleic anhydride reaction. As a result, the adduct has
more uniform molecular size, which provides better dispersancy. In
contrast, PIB decomposes at high temperature, resulting in reduced
product yields and lower product quality.
[0029] The dispersants are admixed with lubricant base stocks to
form the lubricant blends of the present disclosure. Any known base
stock may be employed, including those of Group I, Group II,
Group+, Group III, Group III+, Group IV, and Group V. Gas-to-liquid
(GTL) base stocks, which are sometimes classified as Group III+
base stocks, are also useful. Combinations of the foregoing base
stocks may also be employed. These base stocks may be obtained from
either synthetic or natural/renewable sources.
[0030] The lubricating oil base oil can be any oil boiling in the
lube oil boiling range, typically between 100.degree. C. to
450.degree. C. In the present specification and claims the terms
base oil(s) and base stock(s) are used interchangeably.
[0031] A wide range of lubricating base oils is known in the art.
Lubricating base oils include natural oils and synthetic oils.
Natural and synthetic oils (or mixtures thereof) can be used as
unrefined, refined, or rerefined (the latter is also known as
reclaimed or reprocessed oil). Unrefined oils are those obtained
directly from a natural or synthetic source and used without added
purification. These include shale oil obtained directly from
retorting operations, petroleum oil obtained directly from primary
distillation, and ester oil obtained directly from an
esterification process. Refined oils are similar to the oils
discussed for unrefined oils except refined oils are subjected to
one or more purification steps to improve at least one lubricating
oil property. Purification processes known in the art include
solvent extraction, secondary distillation, acid extraction, base
extraction, filtration, and percolation. Rerefined oils are
obtained by processes analogous to refined oils but using an oil
that has been previously used as feed stock.
[0032] Groups I, II, III, IV and V are broad categories of base oil
stocks developed and defined by the American Petroleum Institute
(API Publication 1509; www.API.org) to create guidelines for
lubricant base oils. Group I base stocks generally have a viscosity
index of 80 to 120 and contain greater than 0.03% sulfur and less
than 90% saturates. Group II base stocks generally have a viscosity
index of 80 to 120, and contain less than or equal to 0.03% sulfur
and greater than or equal to 90% saturates. Group III stocks
generally have a viscosity index greater than 120 and contain less
than or equal to 0.03% sulfur and greater than 90% saturates. Group
IV includes polyalphaolefins (PAO). Group V base stock includes
base stocks not included in Groups I-IV. The table below summarizes
properties of each of these five groups.
TABLE-US-00001 Base Oil Properties Saturates Sulfur Viscosity Index
Group I <90 and/or >0.03% and .gtoreq.80 and <120 Group II
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.80 and <120 Group III
.gtoreq.90 and .ltoreq.0.03% and .gtoreq.120 Group IV Includes
polyalphaolefins (PAO) and GTL products Group V All other base oil
stocks not included in Groups I, II, III or IV
[0033] Useful lubricant base stocks preferably exhibit a pour point
of less than 10.degree. C., more preferably less than 0.degree. C.,
and most preferably less than -10.degree. C. according to ASTM D
97. The lubricant base stocks preferably exhibit a kinematic
viscosity at 40.degree. C. from 4 to 80,000 centi-Stokes (cSt) and
more preferably from 5 cSt to 50,000 cSt at 40.degree. C. according
to ASTM D445. The lubricant base stocks preferably exhibit a
kinematic viscosity at 100.degree. C. of 1.5 to 5,000 cSt, more
preferably 2 cSt to 3,000 cSt, and most preferably 3 cSt to 500
cSt. Low viscosity lubricant base stocks are particularly useful in
automotive motor oil applications, namely those with kinematic
viscosities at 100.degree. C. from 3 cSt to 15 cSt and more
typically 3 cSt to 8 cSt. Low viscosity lubricant base stocks are
particularly useful for 0W20 and 0W30 motor oils.
[0034] Lubricant blends of the present disclosure may optionally
include other conventional lubricant additives, such as detergents,
antioxidants, anti-wear additives, pour point depressants,
viscosity index modifiers, friction modifiers, defoaming agents,
corrosion inhibitors, wetting agents, rust inhibitors, seal swell
agents and the like. The additives may be incorporated to make a
finished lubricant product that has desired viscosity and physical
properties. Typical additives used in lubricant formulation can be
found in the book "Lubricant Additives, Chemistry and
Applications", Ed. L. R. Rudnick, Marcel Dekker, Inc. 270 Madison
Ave. New York, N.J. 10016, 2003.
[0035] Lubricant blends of the present disclosure are useful as
oils or greases for any device or apparatus requiring lubrication
of moving and/or interacting mechanical parts, components, or
surfaces. Useful apparatuses include engines and machines. The
lubricant blends are most suitable for use in the formulation of
automotive crank-case lubricants, automotive gear oils,
transmission oils, many industrial lubricants including circulation
lubricant, industrial gear lubricants, grease, compressor oil, pump
oils, refrigeration lubricants, hydraulic lubricants, metal working
fluids. Lubricant blends of the present disclosure are particularly
useful in automotive applications as crank-case oil, i.e., motor
oil.
[0036] Preferred lubricant blends with PAO-based dispersants
preferably exhibit lower viscosities than PIB-based dispersants at
equal amounts and at comparable molecular weights and more
preferably do so across a temperature range of -40.degree. C. to
100.degree. C. Comparative viscosities can be measured by ASTM
method D665-3 for Kv 40, by D665-5 for Kv 100, and ASTM D5293 for
Cold Crank Simulation (CCS).
[0037] The following are examples of the present disclosure and are
not to be construed as limiting.
EXAMPLES
[0038] Lubricant blends containing PAO-based succinimide
(PAO-imide) of the present disclosure were prepared and compared
for viscosity properties with respect to conventional blends
containing PIB-based succinimide (PIB-imide).
[0039] A poly-alpha-olefin (PAO) with M.sub.n of 1160 was
synthesized according to substantially the same procedures set
forth in Example 10 of WO 2007011973, herein incorporated by
reference, at 90.degree. C. and with H.sub.2 feed rate of 5
scc/minute. The polymer fraction was isolated from the crude
product by distillation at 180.degree. C./0.1 millitorr vacuum to
remove any light boiling fraction. This PAO exhibited the same
degree of unsaturation as measured by bromine number as a 900
molecular weight PIB used for the synthesis of commercial
dispersant. The PIB has bromine number of 16.6 and the PAO has
bromine number of 16.
[0040] A PAO-imide dispersant, Example 1, was synthesized according
to the following procedures and compared with the analogous
PIB-imide dispersant, Example 2, of equal molecular weight (Table
1). The resulting succinimide dispersants had very similar overall
N (nitrogen) levels (3.9 and 4.1 wt % N for PIB-imide and
PAO-imide). It is surprising to note that although the starting PIB
and PAO have the same molecular weight and same bromine number, the
PAO-imide has much lower Kv 100.degree. C. and Kv 40.degree. C.
than PIB-imide. Generally, it is preferred to have an oil-diluted
dispersant of Kv 100.degree. C. much less than 200 cS and Kv
40.degree. C. of much less than 10,000 cS. A lower viscosity
dispersant allows broader formulation space for low viscosity, fuel
efficient engine lubricants.
[0041] The dispersants of Example 1 and 2 were blended with a 4 cS
Gr III+ base stock at 10 wt % based on the total weight of the
blend. The PAO-imide blend of Example 3 had a lower Kv at
40.degree. C. and 100.degree. C. than the PIB-imide blend of
Example 4. The lower viscosity is particularly beneficial for
formulating into 0W20 and 0W30 lubricants and motor oils.
[0042] The calculated viscosities at -15.degree. C., -30.degree. C.
and -40.degree. C. for the PAO-imide blend of Example 3 also are
significantly lower than for the PIB-imide blend of Example 4. The
viscosities were calculated according to the extrapolation of VI
calculation by ASTM D2270 method. The lower viscosity for the
blends is particularly beneficial for formulation of low-vis
grade-finished lubricants.
TABLE-US-00002 TABLE 1 Example No. 1 2* Dispersant Type PAO-imide
PIB-imide Kv100.degree. C., cS 36.50 224.50 Kv 40.degree. C., cS
425.60 10,046.40 VI (viscosity index) 120 99 Example No. 3 4 Blend
Properties Wt % SI in Blend 10 10 Blend Properties Kv100.degree.
C., cS 4.55 4.95 Kv 40.degree. C., cS 19.32 21.91 VI 158 159
Calculated Low Temperature Kv at -15.degree. C., cS 314.2 387.9 Kv
at -30.degree. C., cS 1141.5 1464 Kv at -40.degree. C., cS 3338.0
4413 % Less Kv Increase compared to Example 4 100.degree. C. Kv
reduction 7.8 Control 40.degree. C. Kv reduction 13.4 Control
-15.degree. C. Kv reduction 23.5 Control -30.degree. C. Kv
reduction 28.3 Control -40.degree. C. Kv reduction 32.2 Control
*not an example of the present disclosure
[0043] The two dispersants used in the blends of Example 5 and 6
were synthesized in the same manner as the dispersants used in
Example 1 and 2 except no diluent oil was added to the final step
for the succinimide synthesis. The PAO-imide blend of Example 5 and
the PIB-imide blend of Example 6 were prepared with a 4 cS Gr III+
base stock. The properties of the blends of Example 7 and 8, and
the dispersants PAO-imide and PIB-imide are summarized in Table 2.
Similar reduction of viscosity was observed with the PAO-imide
blend (Example 5). This example further demonstrated the advantages
of PAO-imide dispersants in that the blend exhibited very low
viscosity and good VI compared to the blend having PTB-imide.
Because of low viscosity, the PAO-imide is easy to handle during
synthesis and no diluent oil was needed at the end of the synthesis
to cut down oil viscosity. It is desirable to avoid use of diluent
oil as it allows for better control of base stock purity in the
final formulation. Generally, it is preferred to have pure
dispersant of Kv 100.degree. C. less than 700 cS and a Kv
40.degree. C. of less than 60,000 cS. A lower viscosity dispersant
without diluent oil affords broader formulation tolerance in low
viscosity, fuel efficient, engine lubricants.
TABLE-US-00003 TABLE 2 Example No. 5 6* Dispersant Type PAO-imide
PIB-imide Kv 100.degree. C., cS 96.77 788.67 Kv 40.degree. C., cS
1,344.00 60,985.31 VI 156 134 Example No. 7 8 Wt % SI in Blend 10
10 Blend Properties Kv 100.degree. C., cS 4.65 5.08 Kv 40.degree.
C., cS 19.90 23.15 VI 159 155 Calculated Low Temperature Kv at
-15.degree. C., cS 328.1 441.1 Kv at -30.degree. C., cS 1198.1
1729.8 Kv at -40.degree. C., cS 3516.6 5392.5 % Kv Reduction
Compared to PIB-imide blend %100.degree. C. Kv reduction 8.2
control % 40.degree. C. Kv reduction 16.3 control % -15.degree. C.
Kv reduction 34.4 control % -30.degree. C. Kv reduction 44.4
control % -40.degree. C. Kv reduction 53.3 control *not an example
of the present disclosure
Synthesis Procedures:
Synthesis of PAO-imide (poly-alpha-olefin succinimide, Example
1)
[0044] A PAO (as described above, 75 g) was added to a round-bottom
flask equipped with N.sub.2 inlet, stirrer, and condenser together
with crushed maleic anhydride (15 g, 2 eq). The system was flushed
with nitrogen and the mixture heated to 142.degree. C. with
vigorous stirring for 6 hours. The unreacted maleic anhydride was
stripped by heating under nitrogen stream at 200.degree. C. The
saponification number of the product, PAO-succinic anhydride
(PAO-SA), was 79.6.
[0045] A four-necked flask equipped with Dean Stark trap,
condenser, thermometer, stirrer and nitrogen inlet was charged with
mPAO-SA (50 g, 1 eq), a commercial mixture of ethylene polyamines
(tetraethylepentamine or TEPA**, 9.4 g, 1 eq) and diluent oil (100
sec Solvent dewaxed, paraffinic neutral, 25 g). The mixture was
heated to 138.degree. C. and stirred for 4 hours. The warm product
was filtered. IR analysis confirmed complete reaction. Yield: 80.0
g of a clear, brown fluid.
Synthesis of PIB-imide (polyisobutylene succinimide, Example 2)
[0046] PIB (Aldrich product no 388696, 125 g) was added to a
round-bottom flask equipped with N.sub.2 inlet, stirrer, and
condenser, together with crushed maleic anhydride (26.6 g, 2 eq
based on 900 M.sub.n of PIB). The system was flushed with nitrogen
and the mixture heated to 110.degree. C. with vigorous stirring for
30 minutes. The reaction mixture was heated at 207.degree.
C-234.degree. C. and stirred for 5.5 hours. Remaining maleic
anhydride was stripped by heating under nitrogen stream at
200.degree. C. The saponification number of the product,
PIB-succinic anhydride (PIB-SA) was 80.3.
[0047] A four-necked flask equipped with Dean-Stark trap,
condenser, thermometer, stirrer and nitrogen inlet was charged with
mPIB-SA (94 g, 1 eq), a commercial mixture of ethlene polyamines
(tetraethylenepentamine or TEPA**, 17.7 g, 1 eq) and diluent oil
(100 sec Solvent dewaxed, paraffinic neutral, 50 g). The mixture
was heated to 138.degree. C. and begin stirred for 4 hours. The
warm product was filtered. IR analysis confirmed complete reaction.
Yield: 148.0 clear, viscous, brown fluid. *The saponification test
method was similar to ASTM D94 method. It was used to measure the
amount of anhydride functionality in the succinic anhydride
product.**TEPA is mixture of mostly triethylenetetraamines,
tetraethylenepentamine, pentaethylenehexamine and was obtained from
The Dow Chemical Company.
* * * * *
References