U.S. patent application number 10/678457 was filed with the patent office on 2004-07-08 for high viscosity-index base stocks, base oils and lubricant compositions and methods for their production and use.
Invention is credited to Baillargeon, David J., Cody, Ian Alfred, Fyfe, Kim Elizabeth, Gallagher, John E. JR., Gleeson, James William, Hantzer, Sylvain S., Kim, Jeenok T., Larkin, David W., Murphy, William John, Sanchez, Eugenio.
Application Number | 20040129603 10/678457 |
Document ID | / |
Family ID | 32096886 |
Filed Date | 2004-07-08 |
United States Patent
Application |
20040129603 |
Kind Code |
A1 |
Fyfe, Kim Elizabeth ; et
al. |
July 8, 2004 |
High viscosity-index base stocks, base oils and lubricant
compositions and methods for their production and use
Abstract
This invention relates to base stocks and base oils that exhibit
an unexpected combination of high viscosity index (130 or greater)
and a ratio of measured-to-theoretical high-shear/low-temperature
viscosity at -30C or lower and the methods of making them.
Specifically, the present invention relates to
low-volatility/low-viscosity lubricant base stocks, lubricant base
stocks and base oils, formulated lubricant compositions or
functional fluids comprising these base stocks and methods of
making them. More particularly, this invention relates to lubricant
compositions of low-temperature flow capability and low viscosity
for passenger car motor lubricants of SAE 0W-XX grade (where XX=40
or lower), methods for optimizing fuel economy using the same, and
methods or processes to produce them.
Inventors: |
Fyfe, Kim Elizabeth;
(Sarnia, CA) ; Sanchez, Eugenio; (Turnersville,
NJ) ; Baillargeon, David J.; (Cherry Hill, NJ)
; Gleeson, James William; (Sewell, NJ) ; Cody, Ian
Alfred; (Baton Rouge, LA) ; Murphy, William John;
(Baton Rouge, LA) ; Hantzer, Sylvain S.;
(Prairieville, LA) ; Larkin, David W.; (Baton
Rouge, LA) ; Gallagher, John E. JR.; (Fairfax
Station, VA) ; Kim, Jeenok T.; (Fairfax, VA) |
Correspondence
Address: |
ExxonMobil Research and Engineering Company
P.O. Box 900
Annandale
NJ
08801-0900
US
|
Family ID: |
32096886 |
Appl. No.: |
10/678457 |
Filed: |
October 3, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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60416865 |
Oct 8, 2002 |
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|
60432488 |
Dec 11, 2002 |
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Current U.S.
Class: |
208/18 ;
208/19 |
Current CPC
Class: |
C10N 2020/02 20130101;
C10N 2040/25 20130101; C10G 45/62 20130101; C10G 45/08 20130101;
C10N 2060/02 20130101; C10G 45/64 20130101; C10G 69/00 20130101;
C10G 45/12 20130101; C10N 2030/54 20200501; C10M 171/02 20130101;
C10N 2030/02 20130101; C10M 2203/1006 20130101; C10M 2205/173
20130101; B01J 29/041 20130101; C10N 2030/74 20200501; B01J 29/74
20130101; C10N 2020/085 20200501; C10G 65/043 20130101; C10M
2203/1006 20130101; C10M 2203/1006 20130101; C10M 2205/173
20130101; C10M 2205/173 20130101 |
Class at
Publication: |
208/018 ;
208/019 |
International
Class: |
C10M 159/00 |
Claims
What is claimed is:
1. A base stock or base oil comprising the properties of: (a) a
viscosity index (VI) of about 130 or greater, (b) a pour point of
about -10C or lower, (c) a ratio of measured-to-theoretical
low-temperature viscosity equal to about 1.2 or less, at a
temperature of about -30C or lower, where the measured viscosity is
cold-crank simulator viscosity and where theoretical viscosity is
calculated at the same temperature using the Walther-MacCoull
equation, wherein said base stock or base oil is not a Group IV
base stock or base oil.
2. A base stock or base oil comprising the properties of: (a) a
viscosity index (VI) of about 130 or greater, (b) a pour point of
about -10C or lower, (c) a ratio of measured-to-theoretical
low-temperature viscosity equal to about 1.2 or less, at a
temperature of about -30C or lower, where the measured viscosity is
cold-crank simulator viscosity and where theoretical viscosity is
calculated at the same temperature using the Walther-MacCoull
equation, and (d) a percent Noack volatility no greater than that
calculated by the formula -6.882Ln(CCS@-35C)+67.647, where CCS@-35C
is the base oil CCS viscosity in centipoise, tested at -35C, and
that value as used in the equation is less than 5500 cP, and
wherein said base stock or base oil is not a Group IV base stock or
base oil.
3. A base stock or base oil with a VI of at least 130 produced by a
process which comprises: (1) hydrotreating a feedstock having a wax
content of at least about 60 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to 6500F
(343.degree. C.) minus products to produce a hydrotreated feedstock
whose VI increase is less than 4 greater than the VI of the
feedstock; (2) stripping the hydrotreated feedstock to separate
gaseous from liquid product; and (3) hydrodewaxing the liquid
product with a dewaxing catalyst which is at least one of ZSM-48,
ZSM-57, ZSM-23, ZSM-22, ZSM-35, ferrierite, ECR-42, ITQ-13, MCM-71,
MCM-68, beta, fluorided alumina, silica-alumina or fluorided silica
alumina under catalytically effective hydrodewaxing conditions
wherein the dewaxing catalyst contains at least one Group 9 or
Group 10 noble metal.
4. A base stock or base oil with a VI of at least 130 produced by a
process which comprises: (1) hydrotreating a feedstock having a wax
content of at least about 50 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to
650.degree. F. (343.degree. C.) minus products to produce a
hydrotreated feedstock to produce a hydrotreated feedstock whose VI
increase is less than 4 greater than the VI of the feedstock; (2)
stripping the hydrotreated feedstock to separate gaseous from
liquid product; (3) hydrodewaxing the liquid product with a
dewaxing catalyst which is at least one of ZSM-22, ZSM-23, ZSM-35,
ferrierite, ZSM-48, ZSM-57, ECR-42, ITQ-13, MCM-68, MCM-71, beta,
fluorided alumina, silica-alumina or fluorided silica-alumina under
catalytically effective hydrodewaxing conditions wherein the
dewaxing catalyst contains at least one Group 9 or 10 noble metal;
and (4) hydrofinishing the product from step (3) with a mesoporous
hydrofinishing catalyst from the M41S family under hydrofinishing
conditions.
5. A base stock or base oil with a VI of at least 130 produced by a
process which comprises: (1) hydrotreating a feedstock having a wax
content of at least about 60 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to
650.degree. F. (343.degree. C.) minus products to produce a
hydrotreated feedstock to produce a hydrotreated feedstock whose VI
increase is less than 4 greater than the VI of the feedstock; (2)
stripping the hydrotreated feedstock to separate gaseous from
liquid product; (3) hydrodewaxing the liquid product with a
dewaxing catalyst which is ZSM-48 under catalytically effective
hydrodewaxing conditions wherein the dewaxing catalyst contains at
least one Group 9 or 10 noble metal; and (4) Optionally,
hydrofinishing the product from step (3) with MCM-41 under
hydrofinishing conditions.
6. The process as in claim 3, 4, or 5 wherein said feedstock is a
synthetic gas to liquid feedstock.
7. The process as in claims 3, 4, or 5 wherein said feedstock is
made by a Fischer-Tropsch process.
8 A lubricant comprising the base stock or base oil of claims 1, 2,
3, 4 or 5.
9. A lubricant comprising the base stock or base oil of claims 1,
2, 3, 4 or 5. and at least one performance enhancing additive.
10. A lubricant comprising a base stock or base oil, said base
stock or base oil having the properties of: (a) a viscosity index
(VI) of about 130 or greater, (b) a pour point of about -10C or
lower, (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to about 1.2 or less, at a temperature of about
-30C or lower, where the measured viscosity is cold-crank simulator
viscosity and where theoretical viscosity is calculated at the same
temperature using the Walther-MacCoull equation. wherein said base
stock or base oil is not a Group IV base stock or base oil.
11. A lubricant comprising a base stock or base oil, said base
stock or base oil having the properties of: (a) a viscosity index
(VI) of about 130 or greater, (b) a pour point of about -10C or
lower, (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to about 1.2 or less, at a temperature of about
-30C or lower, where the measured viscosity is cold-crank simulator
viscosity and where theoretical viscosity is calculated at the same
temperature using the Walther-MacCoull equation, and (d) a percent
Noack volatility no greater than that calculated by the formula
-6.882Ln(CCS@-35C)+67.647, where CCS@-35C is the base oil CCS
viscosity in centipoise, tested at -35C, and that value as used in
the equation is less than 5500 cP, and wherein said base stock or
base oil is not a Group IV base stock or base oil.
12. A lubricating comprising at least one base stock or base oil
wherein said base stock or base oil has a VI of at least 130
produced by a process which comprises: (1) hydrotreating a
feedstock having a wax content of at least about 60 wt. %, based on
feedstock, with a hydrotreating catalyst under effective
hydrotreating conditions such that less than 5 wt. % of the
feedstock is converted to 6500F (343.degree. C.) minus products to
produce a hydrotreated feedstock whose VI increase is less than 4
greater than the VI of the feedstock; (2) stripping the
hydrotreated feedstock to separate gaseous from liquid product; and
(3) hydrodewaxing the liquid product with a dewaxing catalyst which
is at least one of ZSM-48, ZSM-57, ZSM-23, ZSM-22, ZSM-35,
ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta, fluorided
alumina, silica-alumina or fluorided silica alumina under
catalytically effective hydrodewaxing conditions wherein the
dewaxing catalyst contains at least one Group 9 or Group 10 noble
metal.
13. A lubricant comprising at least one base stock or base oil
wherein said base stock has a VI of at least 130 produced by a
process which comprises: (1) hydrotreating a lubricating oil
feedstock having a wax content of at least about 50 wt. %, based on
feedstock, with a hydrotreating catalyst under effective
hydrotreating conditions such that less than 5 wt. % of the
feedstock is converted to 650.degree. F. (343.degree. C.) minus
products to produce a hydrotreated feedstock to produce a
hydrotreated feedstock whose VI increase is less than 4 greater
than the VI of the feedstock; (2) stripping the hydrotreated
feedstock to separate gaseous from liquid product; (3)
hydrodewaxing the liquid product with a dewaxing catalyst which is
at least one of ZSM-22, ZSM-23, ZSM-35, ferrierite, ZSM-48, ZSM-57,
ECR-42, ITQ-13, MCM-68, MCM-71, beta, fluorided alumina,
silica-alumina or fluorided silica-alumina under catalytically
effective hydrodewaxing conditions wherein the dewaxing catalyst
contains at least one Group 9 or 10 noble metal; and (4)
hydrofinishing the product from step (3) with a mesoporous
hydrofinishing catalyst from the M41S family under hydrofinishing
conditions.
14. A lubricant comprising at least one base stock wherein said
base stock has a VI of at least 130 produced by a process which
comprises: (1) hydrotreating a lubricating oil feedstock having a
wax content of at least about 60 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to
650.degree. F. (343.degree. C.) minus products to produce a
hydrotreated feedstock to produce a hydrotreated feedstock whose VI
increase is less than 4 greater than the VI of the feedstock; (2)
stripping the hydrotreated feedstock to separate gaseous from
liquid product; (3) hydrodewaxing the liquid product with a
dewaxing catalyst which is ZSM-48 under catalytically effective
hydrodewaxing conditions wherein the dewaxing catalyst contains at
least one Group 9 or 10 noble metal; and (4) Optionally,
hydrofinishing the product from step (3) with MCM-41 under
hydrofinishing conditions.
15. The lubricant as in claim 12, 13 or 14 wherein said feedstock
is a synthetic gas to liquid feedstock.
16. The lubricant as in claims 12, 13 or 14 wherein said feedstock
is made by a Fischer-Tropsch process.
17. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 7000 at -25C and the Noack
Volatitlity is less than or equal to about 15 wt %.
18. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 6600 at -30C and the Noack
Volatitlity is less than or equal to about 15 wt %.
19. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 6200 at -35C and the Noack
Volatitlity is less than or equal to about 15 wt %.
20. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 7000 at -25C and the Noack
Volatitlity is less than or equal to about 13 wt %.
21. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 6600 at -30C and the Noack
Volatitlity is less than or equal to about 13 wt %.
22. A lubricant composition comprising the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5, wherein the CCS viscosity
is less than or equal to about 6200 at -35C and the Noack
Volatitlity is less than or equal to about 13 wt %.
23. A viscosity modifier solution comprising a viscosity modifier
blended into the base stock of base oil of any one of the claims 1,
2, 3, 4 or 5.
24. An additive concentrate comprising the base stock or base oil
of any one of the claims 1, 2, 3, 4 or 5.
25. The method of making a lubricant comprising incorporating a
base stock or base oil having the properties of (a) a viscosity
index (VI) of 130 or greater, (b) a pour point of -10C or lower,
(c) a ratio of measured-to-theoretical low-temperature viscosity
equal to 1.2 or less, at a temperature of -30C or lower, where the
measured viscosity is cold-crank simulator viscosity and where
theoretical viscosity is calculated at the same temperature using
the Walther-MacCoull equation. wherein said base stock or base oil
is not a Group IV base stock or base oil.
26. The method of making a lubricant comprising incorporating a
base stock or base oil having the properties of (a) a viscosity
index (VI) of 130 or greater, (b) a pour point of -10C or lower,
(c) a ratio of measured-to-theoretical low-temperature viscosity
equal to 1.2 or less, at a temperature of -30C or lower, where the
measured viscosity is cold-crank simulator viscosity and where
theoretical viscosity is calculated at the same temperature using
the Walther-MacCoull equation, and (d) a percent Noack volatility
no greater than that calculated by the formula
-6.882Ln(CCS@-35C)+67.647, where CCS@-35C is the base oil CCS
viscosity in centipoise, tested at -35C, and that value as used in
the equation is less than 5500 cP, and wherein said base stock or
base oil is not a Group IV base stock or base oil.
27. The method of making an additive concentrate incorporating a
base stock or base oil having the properties of (a) a viscosity
index (VI) of 130 or greater, (b) a pour point of -10C or lower,
(c) a ratio of measured-to-theoretical low-temperature viscosity
equal to 1.2 or less, at a temperature of -30C or lower, where the
measured viscosity is cold-crank simulator viscosity and where
theoretical viscosity is calculated at the same temperature using
the Walther-MacCoull equation. wherein said base stock or base oil
is not a Group IV base stock or base oil.
28. The method of making an additive concentrate comprising
incorporating a base stock or base oil having the properties of (a)
a viscosity index (VI) of 130 or greater, (b) a pour point of -10C
or lower, (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation, and (d) a percent Noack
volatility no greater than that calculated by the formula
-6.882Ln(CCS@-35C)+67.647, where CCS@-35C is the base oil CCS
viscosity in centipoise, tested at -35C, and that value as used in
the equation is less than 5500 cP, and wherein said base stock or
base oil is not a Group IV base stock or base oil.
29. The method of making an additive concentrate comprising
incorporating a base stock or base oil of any one of the claims 3,
4 or 5.
30. The method of making a lubricant comprising incorporating said
additive concentrate of either claim 27 or 28.
31. The method of making a lubricant comprising incorporating an
additive concentrate comprising incorporating a base stock or base
oil of any one of the claims 3, 4 or 5.
32. A method of improving the CCS viscosity of a base stock
comprising incorporating said base stock or base oil of any one of
the claims 1, 2, 3, 4 or 5.
33. A method of improving the CCS viscosity of a lubricant
comprising incorporating a base stock or base oil of any one of the
claims 1, 2, 3, 4 or 5.
34. A method of reducing the Noack volatility of a base stock
comprising incorporating a base stock or base oil of any one of the
claims 1, 2, 3, 4 or 5.
35. A method of reducing the Noack volatility of a lubricant
comprising incorporating a base stock or base oil of any one of the
claims 1, 2, 3, 4 or 5.
36. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
7000 at -25C and the Noack Volatility is less than or equal to
about 15 wt %.
37. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
6600 at -30C and the Noack Volatility is less than or equal to
about 15 wt %.
38. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
6200 at -35C and the Noack Volatility is less than or equal to
about 15 wt %.
39. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
7000 at -25C and the Noack Volatility is less than or equal to
about 13 wt %.
40. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
6600 at -30C and the Noack Volatitlity is less than or equal to
about 13 wt %.
41. A method of improving a lubricant by admixing the base oil or
base stock of any one of the claims 1, 2, 3, 4 or 5, wherein the
CCS viscosity of the final mixture is less than or equal to about
6200 at -35C and the Noack Volatitlity is less than or equal to
about 13 wt %.
42. A method of reducing the viscosity of a viscosity modifier
solution by dispersing said solution in the base oil or base stock
of any one of the claims 1, 2, 3, 4 or 5.
Description
[0001] This application claims the benefit of U.S. Provisional
Application No. 60/416,865 filed Oct. 8, 2002 and U.S. Provisional
Application No. 60/432,488 filed Dec. 11, 2002.
FIELD OF THE INVENTION
[0002] This invention relates to base stocks and base oils that
exhibit an unexpected combination of high viscosity index (130 or
greater), a ratio of measured-to-theoretical
high-shear/low-temperature viscosity at -30C or lower and the
methods of making them. Specifically, the present invention relates
to low-volatility/low-viscosity lubricant base stocks, lubricant
base stocks and base oils, formulated lubricant compositions or
functional fluids comprising these base stocks and methods of
making them. More particularly, this invention relates to lubricant
compositions of low-temperature flow capability and low viscosity
for passenger car motor lubricants of SAE 0W-XX grade (where XX=40
or lower), methods for optimizing fuel economy using the same, and
methods or processes to produce them.
BACKGROUND OF THE INVENTION
[0003] The API 1509 Engine Oil Licensing and Certification System,
Appendix E, defines base stocks (as opposed to base oils and
lubricant compositions) as an hydrocarbon stream produced by a
single manufacturer to the same specifications (independent of feed
source or manufacturers location) and that is identified by a
unique formula, product identification number, or both. Base stocks
may be manufactured using a variety of different processes
including but not limited to distillation, solvent refining,
hydrogen processing, oligomerization, esterification, and
rerefining. Rerefined stock shall be substantially free from
materials introduced through manufacturing, contamination or
previous use. A base stock slate is a product line of base stocks
that have different viscosities but are in the same base stock
grouping and from the same manufacturer. A base oil is the base
stock or blend of base stocks used in formulated lubricant
compositions. A lubricant composition may be a base stock, a base
oil, either alone or mixed with other stocks, oils or functional
additives.
[0004] The gasoline and diesel engine manufacturers in North
America, Europe and Asia Pacific demand lubricants of increasingly
higher quality and higher performance. Both the North American and
European automobile manufacturers associations are regularly
introducing new performance categories that simultaneously reflect
and stimulate improvements in lubricant quality and performance.
Key performance areas are fuel economy, longer drain intervals with
extended performance retention, better soot handling, lower
emissions, and improved low-temperature performance. Several of
these performance features push the industry to use base stocks
with lower viscosity, better oxidation stability, lower volatility,
higher saturates, lower sulphur, lower nitrogen, and lower
aromatics.
[0005] In particular, reduced vehicle emissions are partially
achieved by improved fuel economy and better low-temperature
starting capability (C. J. May, J. J. Habeeb, A. M. White,
Lubrication Engineering, 43 (7), 557-567), both of which lower fuel
consumption and consequently reduce gaseous emissions.
Low-viscosity SAE 0W-XX (where XX=40 or lower) grade lubricants can
demonstrate both of these performance characteristics. FIG. 1
illustrates the relative improvements in fuel economy that can be
achieved by low-viscosity lubricants compared to a typical
high-viscosity lubricant such as SAE 20W-50 (fuel economy
improvement equal to 0.44% versus SAE 40 grade reference
lubricant). For example, the SAE 0W-30 viscosity grade can achieve
over 2.51% fuel economy improvement versus the same reference
lubricant.
[0006] Low-viscosity SAE 0W-XX grade lubricants can be made with a
variety of low-viscosity base stocks and base oils. However, in
general, as base oil viscosity decreases, the corresponding base
oil volatility increases. High volatility may significantly
constrain the use of certain low-viscosity base stocks and base
oils in formulated lubricant products due to volatility limitations
or severe performance requirements of, for example, API, ILSAC, or
ACEA product quality standards. The product volatility limits of
API SL/ILSAC GF-3 and ACEA A1-02/B1-02 or ACEA A2-96 issue 3/B2-98
issue 2 (i.e. 15 wt % Noack volatility) introduce some base oil
limitations.
[0007] The lower volatility limits for formulated lubricants, of
ACEA A3-02/B3-98 (13 wt % Noack volatility), coupled with
volatility/low-temperature viscosity profiles of current commercial
high-quality, paraffinic base stocks (one example of which might be
a Group III base stocks and base oils), significantly restrict the
numbers of base stocks that have sufficiently good low-temperature
properties on their own to formulate to the viscosity and
volatility limits of a SAE 0W-XX grade without the use of expensive
special co-base stocks and base oils. Often, special co-base stocks
and base oils may also have other significant disadvantages besides
expense, such as limited supply, or performance limitations in
selected areas that may contribute to overall poor performance of
the formulated lubricant. A successful base oil would provide the
required low-temperature flow capability, the required
high-temperature viscosity, and the required limited evaporative
loss. In the past, only base stocks and base oils consisting
largely or exclusively of synthesized polyalphaolefin hydrocarbon
Group IV base stocks have been able to meet these
specifications.
[0008] Tests used in describing lubricant compositions of this
invention are:
[0009] (a) CCS viscosity measured by Cold Cranking Simulator Test
(ASTM D5293);
[0010] (b) Noack volatility (or evaporative loss) measured by
CEC-L-40-A-93;
[0011] (c) Viscosity index (VI) measured by ASTM D2270;
[0012] (d) Theoretical viscosity calculated by Walther-MacCoull
equation (ASTM D341 appendix 1);
[0013] (e) Kinematic viscosity measured by ASTM D445
[0014] (f) Pour point as measured by ASTM D5950.
[0015] (g) Scanning Brookfield Viscosity as measured by ASTM
D5133
[0016] (h) Brookfield Viscosity as measured by ASTM D2983.
[0017] The inventors note that the Walther-MacCaull equation of
ASTM D341 computes a theoretic kinematic viscosity, while the CCS
reports an absolute viscosity. To compute the ratio as used herein,
the inventors converted the Walther-MacCaull viscosity as per
equation (I).
Theoretical viscosity@T.sub.1(.degree. C.)=Walther-MacCaull
Calculated Kinematic Viscosity@T.sub.1(.degree. C.).times.Density
at T.sub.1(.degree. C.) (I)
[0018] where T.sub.1 is the desired temperature.
[0019] The density at -35.degree. C. is estimated from the density
at 20.degree. C. using well-known formula. See, e.g., A. Bondi,
"Physical Chemistry of Lubricating Oils", 1951, p. 5.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 graphically illustrates the effects of lubricant
viscosity on fuel economy improvement.
[0021] FIG. 2 graphically compares the measured CCS viscosities
against the predicted Walther-MacCoull viscosities at various
temperatures.
[0022] FIG. 3 graphically illustrates the viscosity versus Noack
volatility profiles for various oils.
[0023] FIG. 4 graphically compares the kinematic viscosity versus
CCS viscosity for various inventive oils and comparative
examples.
SUMMARY OF THE INVENTION
[0024] This invention relates to base stocks and base oils that
achieve improved viscosity performance at low temperatures (about
-25C or lower). The present invention also relates to formulated
lubricant compositions which comprise a base oil derived from waxy
hydrocarbon feedstocks, either from natural or, mineral, or
synthetic sources (e.g. Fischer-Tropsch-type processes), and which
may be used to meet the simultaneous requirements of
low-temperature viscosity and good volatility of SAE 0W-XX (XX=40
or lower) grade lubricants. This invention also relates to
processes or methods to make such base oils, base stocks, and
formulated lubricant compositions.
[0025] More specifically, this invention encompasses base stocks
that have the surprising and unexpected simultaneous combination of
properties of:
[0026] (a) viscosity index (VI) of 130 or greater,
[0027] (b) a pour point of -10C or lower,
[0028] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation.
[0029] The base oil compositions of this invention encompass not
only individual base stocks as manufactured, but also mixtures or
blends of two or more base stocks and/or base oils such that the
resulting mixture or blend satisfies the base stock requirements of
this invention. The base oil compositions of this invention
encompass a range of useful viscosities, with base oil kinematic
viscosity at 100C of about 1.5 cSt to 8.5 cSt, preferably about 2
cSt to 8 cSt, and more preferably about 3 cSt to 7.5 cSt. The base
oils of this invention encompasses a range of useful pour points,
with pour points of about -10C to greater than -30C, preferably
about -12C to greater than -30C, and more preferably about -14C to
greater than -30C. In some instances, the pour point may range from
-18C to -30C and may further range from -20C to -30C.
[0030] This invention further encompasses base oils that have the
surprising and unexpected simultaneous combination of properties
of:
[0031] (a) a viscosity index (VI) of 130 or greater,
[0032] (b) a pour point of -10C or lower,
[0033] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation, and
[0034] (d) a percent Noack volatility no greater than that
calculated by the formula--6.882Ln(CCS@-35C)+67.647, where CCS@-35C
is the base oil CCS viscosity in centipoise, tested at -35C, and
where CCS@-35C is less than 5500 cP, and Ln(x) is the natural log
of x.
[0035] Preferably, the base stocks and base oils of this invention
as used herein will have a measured-to-theoretical low-temperature
viscosity of about 0.8 to about 1.2 at a temperature of -30C or
lower, where the measured viscosity is cold-crank simulator
viscosity and where theoretical viscosity is calculated at the same
temperature using the Walther-MacCoull equation
[0036] One embodiment of this invention encompasses base stocks and
base oils that have defined parameters for low-temperature
viscosity and volatility recited herein, and that may be used in
formulated lubricant compositions that are capable of meeting the
viscosity requirements of SAE 0W-XX (XX=40 or lower) graded oil as
described by SAE J300-99, and the volatility requirements of no
greater than 13 wt % Noack volatility (as defined by ACEA A3-02 or
ACEA B3-98). Another embodiment is a lubricant comprising this base
stock or base oil with the addition of at least one performance
additive. Yet another embodiment of this invention encompasses
functional fluids comprising one or more than one inventive base
stocks or base oils with the properties described above and at
least one performance additive.
[0037] Performance additives as used in this invention may
encompass, for example, individual additives as components,
combinations of one or more individual additives or components as
additive systems, combinations of one or more additives with one or
more suitable diluent oils as additive concentrates or packages.
Additive concentrate encompasses component concentrates as well as
additive packages. Often in making or formulating lubricant
compositions or functional fluids, viscosity modifiers or viscosity
index improvers may be used individually as components or
concentrates, independent of the use of other performance additives
in the form of components, concentrates, or packages. The amount
and type of performance additives that may be combined with base
stocks and base oils of this invention are limited such that the
total mixture comprising one or more of the inventive base stocks
and base oils plus one or more performance additives does not
exceed the viscometric limits required for SAE 0W-XX (XX=40 or
lower) grade oils and have no greater than 13 wt % Noack volatility
(as defined by ACEA A3-02 or by ACEA B3-98).
[0038] Surprisingly, the low measured-to-theoretical viscosity
ratio, which distinguishes one unexpected performance advantage of
the base stocks and base oils of this invention, can also be
expected to be observed at temperatures below -35C, for example
down to -40C or even lower. Thus at these low temperatures, actual
viscosity of base stocks and base oils of this invention would be
expected to approach the desired, ideal, theoretical viscosity,
while comparative base stocks and base oils would be expected to
deviate even more strongly away from theoretical viscosity (i.e. to
higher measured-to-theoretical viscosity ratios).
[0039] Additionally, the base stocks and base oils of this
invention may have the following properties:
[0040] (a) saturates content of at least 90 wt %, and
[0041] (b) a sulfur content of 0.03 wt. % or less
[0042] Viscosity index of the inventive base stocks and base oils
may be 130 or greater, or preferably 135 or greater and in some
instances, 140 or greater. The desired pour point of the inventive
base stocks and base oils is about -10C or lower, or preferably
-12C or lower, or in some instances more preferably -14C or lower.
In some instances the pour point may be -18 or lower and more
preferably, -20C and lower. For the inventive base stocks and base
oils, the desired measured-to-theoretical ratio of low-temperature
cold cranking simulator (CCS) viscosity equals about 1.2 or less,
or preferably about 1.16 or less, or more preferably about 1.12 or
less. For the low-temperature viscosity profiles of the inventive
base stocks and base oils, the desired inventive base stocks and
base oils have CCS viscosity @-35C of less than 5500 cP, or
preferably less than 5200 cP, or in some instances more preferably
less than 5000 cP.
[0043] Base stocks and base oils of this invention may be used with
other lubricant base stocks and base oils or co-base stocks and
base oils in formulated lubricant compositions or functional
fluids. In some instances, the highly advantageous low-temperature
(-30C or lower) properties of these inventive base stocks and base
oils can beneficially improve the performance of finished lubricant
compositions or functional fluids at concentrations of 20 wt % or
greater of the total base stocks and base oils contained in such
compositions. Preferably, the inventive base stocks and base oils
may be used in combination with other individual base stocks and
base oils to gain significant low-temperature performance benefits
in finished lubricant compositions or functional fluids. More
preferably, the base stocks and base oils may be used at 40 wt % or
more of the total base stocks and base oils contained in formulated
lubricant compositions or functional fluids, without detracting
from the elements of this invention. And in certain instances, the
base oil(s) may be most preferably used at 50 wt % or more of the
total base stocks and base oils, or even 70 wt % or more of the
total base stocks and base oils in finished lubricant compositions
or functional fluids.
[0044] The base stocks and base oils of the present invention may
be produced by:
[0045] (a) hydrotreating a feedstock having a wax content of at
least about 50 wt. %, based on feedstock, with a hydrotreating
catalyst under effective hydrotreating conditions such that less
than 5 wt. % of the feedstock is converted to 650F (343C) minus
products to produce a hydrotreated feedstock whose VI increase is
less than 4 greater than the VI of the feedstock;
[0046] (b) stripping or distilling the hydrotreated feedstock to
separate gaseous from liquid product; and
[0047] (c) hydrodewaxing the liquid product with a dewaxing
catalyst which is at least one of ZSM-22, ZSM-23, ZSM-35, ZSM-48,
ZSM-57, ferrierite, ECR-42, ITQ-13, MCM-68, MCM-71, beta, fluorided
alumina, silica-alumina or fluorided silica alumina under
catalytically effective hydrodewaxing conditions wherein the
dewaxing catalyst contains at least one Group 9 or Group 10 noble
metal, and
[0048] (d) optionally, hydrofinishing the product from step (c)
with a mesoporous hydrofinishing catalyst from the M41S family
under hydrofinishing conditions.
[0049] Other embodiments of this invention relate to methods of (a)
making formulated lubricant compositions or functional fluids that
comprise inventive base stocks and base oils that have significant
performance benefits in both lower volatility and lower
low-temperature viscosity, (b) making additive concentrates
comprising inventive base stocks and base oils recited herein, (c)
making formulated lubricant compositions or functional fluids
comprising the inventive base stocks and base oils recited herein
with such compositions or fluids meeting the viscosity requirements
of a SAE 0W-XX (XX=40 or lower) graded oil as described by SAE
J300-99, and the volatility requirements of no greater than 13 wt %
Noack volatility (as defined by ACEA A3-02 or ACEA B3-98).
DETAILED DESCRIPTION OF THE INVENTION
[0050] Improved fuel economy and low-temperature start-up
capability are achieved with lubricants or engine oils having the
SAE 0W-XX viscosity grade. However, currently available commercial
Group III base stocks manufactured using available processing
technology do not have sufficiently good low-temperature
performance to formulate to the SAE 0W viscosity limit and maintain
13 wt % maximum Noack volatility. Often special base stocks and
base oils, for example much more expensive, supply-limited Group IV
PAO base stocks, are added to commercial Group III base stocks in
order to meet one or more of the critical performance features of
such SAE 0W-XX grades. A Group III base stock with the enhanced
capability to manufacture SAE 0W-XX lubricants would provide a
cost-effective technology option to provide the market with
lubricants at lower cost while offering higher fuel economy and
reduced emissions.
[0051] The high viscosity index base stocks of this invention have
superior low-temperature performance when compared to other high
viscosity index base stocks. The difference in performance is most
critical in the temperature range below -30C, where conventional
high viscosity index Group III base stocks deviate significantly
from the theoretical viscosity. To illustrate, measured
low-temperature CCS viscosity of comparative conventional high
viscosity index Group III base stocks tends to deviate to higher
viscosity values than that predicted (Walther-MacCoull equation)
for the expected theoretical viscosity of the same base stocks at
low temperatures (FIG. 2).
[0052] The inventive base stocks, base oils and lubricants of this
invention surprisingly demonstrate the more ideal and highly
desirable performance predicted by the theoretical viscosity
behavior of base stocks and base oils, as described according to
the Walther-MacCoull equation (ASTM D341 appendix). In addition,
the base stocks and base oils of this invention are found to be
surprisingly different from available commercial Group III base oil
regarding the ratio of measured-to-theoretical low-temperature
viscosity, where actual viscosity is measured as cold cranking
simulator (CCS) viscosity at temperatures of -30C or lower, and
where theoretical viscosity derives from the Walther-MacCoull
equation (ASTM D341, appendix) at the same temperature as the
measured CCS viscosity. CCS viscosity is measured under high sheer
conditions, whereas Brookfield viscosity is measured under low
sheer conditions.
[0053] The base stocks and base oils of this invention also
demonstrate novel and unexpected performance advantages in having
simultaneously lower volatility and lower viscosity than that of
these comparative Group III base stocks and base oils (FIG. 3). The
low-volatility/low-viscosity base stocks and base oils of this
invention demonstrate advantageous Noack volatilities of less than
about 20 wt %, preferably less than 16 wt %, and more preferably
less than 15 wt %, with low-temperature CCS (cold crank simulator)
viscosities measured at -35C of less than about 5500 cP, preferably
less that about 5200 cP, and in some instances more preferably less
than about 5000 cP. In FIG. 3, the shaded area is defined by the
equation:
Wt % Noack Volatility.ltoreq.-6.882Ln(CCS@-35C)+67.647
[0054] where CCS@-35C is the base oil CCS viscosity in centipoise,
tested at -35C, and where CCS@-35C is less than 5500 cP
[0055] The base stocks and base oils of this invention have the
unique and highly desirable characteristic of a
measured-to-theoretical viscosity ratio of 1.2 or lower, preferably
1.16 or lower, and in many instances more preferably 1.12 or lower.
Base stocks and base oils having measured-to-theoretical viscosity
ratios of less than about 1.2 and with ratios approaching 1.0 are
highly desirable, because lower ratios indicate significant
advantages in low-temperature performance and operability. The
currently available Group III base stocks and base oils, however,
have characteristic measured-to-theoretical viscosity ratios of 1.2
and higher, indicating poorer base oil low-temperature viscosity
and operability. In some instances, it is preferred to have the
measured-to-theoretical viscosity ratio be between about 0.8 and
about 1.2.
[0056] In one embodiment of this invention, the base stocks and
base oils of this invention have the surprising and unexpected
simultaneous combination of properties of:
[0057] (a) viscosity index (VI) of 130 or greater,
[0058] (b) a pour point of -10C or lower,
[0059] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation.
[0060] This invention further encompasses base stocks and base oils
that have the surprising and unexpected simultaneous combination of
properties of:
[0061] (a) viscosity index (VI) of 130 or greater,
[0062] (b) a pour point of -10C or lower,
[0063] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation, and
[0064] (d) a percent Noack volatility no greater than that
calculated by the formula-6.882Ln(CCS @-35C)+67.647, where CCS@-35C
is the base oil CCS viscosity in centipoise, tested at -35C, and
where CCS@-35C is less than 5500 cP.
[0065] As used herein, the term lubricant includes, but is not
limited to, lubricant compositions, formulated lubricant
compositions, lubes, functional fluids, lube products, lube oils,
finished lubes, finished lubricants, lubricating oils, greases and
the like.
[0066] This invention also encompasses lubricants and formulated
lubricant compositions or functional fluids comprising the
inventive base oil compositions with the properties:
[0067] (a) a viscosity index (VI) of 130 or greater,
[0068] (b) a pour point of -10C or lower,
[0069] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or lower,
where the measured viscosity is cold-crank simulator viscosity and
where theoretical viscosity is calculated at the same temperature
using the Walther-MacCoull equation.
[0070] This invention also encompasses lubricants and formulated
lubricant compositions or functional fluids comprising the
inventive base oil compositions with the properties:
[0071] (a) viscosity index (VI) of 130 or greater,
[0072] (b) a pour point of -10C or lower,
[0073] (c) a ratio of measured-to-theoretical low-temperature
viscosity equal to 1.2 or less, at a temperature of -30C or -35C or
lower, where the measured viscosity is cold-crank simulator
viscosity and where theoretical viscosity is calculated at the same
temperature using the Walther-MacCoull equation, and
[0074] (d) a percent Noack volatility no greater than that
calculated by the formula
-6.882Ln(CCS@-35C)+67.647,
[0075] where CCS@-35C is the base oil CCS viscosity in centipoise,
tested at -35C, and where CCS@-35C is less than 5500 cP,
[0076] Noack Volatility (evaporative loss) of the inventive base
stocks and base oils of the is invention may range from less than
about 1 wt % to about 20 wt %, depending on the viscosity of the
particular base stock or base oil. Generally, the inventive base
stocks have advantageous lower volatility properties that are
preferred for many lubricant applications. The inventive base
stocks recited herein may have Noack volatilities of 20 wt % or
less, preferably 18 wt % or less and more preferably, 16 wt % or
less. In some applications, the inventive base stocks and base oils
may have Noack volatilities less than 15 wt %, specifically even
lower than 13 wt %. Additionally, the base stocks and base oils of
this invention may also have the following properties:
[0077] (a) saturates content of at least 90 wt %, and
[0078] (b) a sulfur content of 0.03 wt. % or less.
[0079] Products which incorporate the base stocks or base oils of
this invention clearly have an advantage over other similar
products made from conventional Group III base stocks. One
embodiment of this invention is a formulated lubricant composition
or functional fluids comprising base stocks and base oils of this
invention in combination with one or more additional co-base stocks
and base oils. Another embodiment of this invention is a formulated
lubricant composition or functional fluids comprising base stocks
and base oils of this invention in combination with one or more
performance additives.
[0080] This invention is surprisingly advantageous in applications
where low-temperature properties are important to the performance
of the finished lube or functional fluid. The base stocks and base
oils of this invention may be advantageously used in many of the
following applications, for example hydraulic fluids, compressor
oils, turbine oils, circulating oils, gear oils, paper machine
oils, industrial oils, automotive oils, manual transmission fluids,
automatic transmission fluids, drive train fluids, engine oils, gas
engine oils, aviation piston oils, diesel oils, marine oils,
greases, and the like.
[0081] One embodiment of this invention encompasses an additive
concentrate comprising the inventive base oil with the properties
described herein and one or more performance additives. An additive
concentrate comprising the inventive base oil(s) may encompass
compositions where the inventive base oil is used in concentrations
of from about 1 wt % to 99 wt %, preferably from about 5 wt % to 95
wt %, and more preferably from about 10 wt % to 90 wt %. In some
particular instances, an additive concentrate comprising the
inventive base oil(s) may encompass compositions where the
inventive base oil is used in concentrations of from about 20 wt %
to 80 wt %, and sometime from about 30 wt % to 70 wt %. Mixtures of
the inventive base oil(s) and co-base(s) are also aspects of
suitable additive concentrates.
[0082] One problem the current invention solves is that in order to
manufacture, for example, a SAE 0W-20 or SAE 0W-30 lubricant
meeting the performance specifications of ACEA A5-02/B5-02 or ILSAC
GF-3, both the SAE J300-99 viscosity limits and volatility limits
must be met. Product performance standards ACEA A3-O.sub.2/B3-98
have very low volatility limits for formulated lubricants or
functional fluids, specifically 13 wt % maximum Noack volatility.
The combined constraints of both requirements limit the base stock
options. At present, formulations meeting both SAE SAE 0W-XX (XX=40
or lower) CCS viscosity limits and volatility limits of ACEA
A5-O.sub.2/B5-02 require combinations of base stocks and base oils
that generally require a Group IV base stock component.
[0083] Viscosity grade specifications for lubes as defined by SAE
J300-99 are listed in Table 2. The products of this invention,
e.g., the base stocks, base oils and formulated lubricant
compositions or functional fluids comprising such base stocks and
base oils, are not limited to the grades recited by SAE J300. The
materials of this invention may be expected to have additional
performance advantages at temperatures lower than those recited by
SAE J300, specifically lower that -35C, with even greater
performance differentiation at -40C or lower. Additionally, the
same materials may be expected to satisfy the performance
requirements of grades lower than that of the current SAE 0W Grade,
for example a -5W grade or even a -10W grade.
1TABLE 2 Viscosity Grade Specifications (SAE J300-99)
High-Temperature HTHS Low-Temperature Viscosity Viscosity
Viscosity, CCS Viscosity MRV Kinematic Viscosity at 150 C.,
10.sup.6 (cP) Viscosity (cP) 100 C. (cSt) s.sup.-1 (cP) SAE Grade
Maximum Maximum Minimum Maximum Minimum 0 W 6200 at -35 C. 60000 at
-40 C. 3.8 5 W 6600 at -30 C. 60000 at -35 C. 3.8 10 W 7000 at -25
C. 60000 at -30 C. 4.1 15 W 7000 at -20 C. 60000 at -25 C. 5.6 20 W
9500 at -15 C. 60000 at -20 C. 5.6 25 W 13000 at -10 C. 60000 at
-15 C. 9.3 20 5.6 <9.3 2.6 30 9.3 <12.5 2.9 40 12.5 <16.3
2.9 (PCEO) 40 12.5 <16.3 3.7 (CEO) 50 16.3 <21.9 3.7 60 21.9
<26.1 3.7
[0084] Generally, individual base stocks and base oils that can
successfully be combined with one or more performance additives to
give formulated lubricant compositions or functional fluids that
meet ACEA A3-02/B3-98 volatility standards have base oil Noack
volatility not within the ACEA-related limit of 13 wt % maximum.
Available Group III base stocks and base oils may meet these
volatility limits, but generally at higher base oil viscosity. The
volatility/viscosity profiles of several available commercial Group
III base stocks and base oils is shown in FIG. 3. Used individually
in formulated lubricant compositions, these Group III base stocks
and base oils do not achieve both the low volatility and low
viscosity necessary for the ACEA standards.
[0085] Lubricating oils produced from the base stocks and base oils
made according to the invention meet the requirements of a Group
III base stock and can be prepared in high yields while at the same
time possessing excellent properties such as high VI and low pour
point. Specifically, the present invention allows for the
production of lubricating oils meeting ACEA and ILSAC GF-3
standards of SAE 0W-XX lubricants from Group III base stocks in the
substantial absence of Group IV base stocks.
[0086] An additional embodiment of this invention encompasses
formulated lubricant compositions or functional fluids comprising
the inventive base oil and at least one performance additive, with
such formulated lubricant compositions or functional fluids meeting
the viscometric requirements of SAE 0W-XX (XX=40 or lower) grade
lubricants and having no greater than 13 wt % Noack volatility (as
defined by ACEA A3-02 or ACEA B3-98).
[0087] While not limited to the SAE specifications, the amount and
type of co-base stocks and base oils that may be used with the base
stocks and base oils of this invention are limited such that the
total mixture comprising one or more of the inventive base stocks
and base oils plus one or more co-base stocks and base oils plus
optionally one or more performance additives preferably such that
the lubricant does not exceed the viscometric limits required for
SAE 0W-XX (XX=40 or lower) grade engine oils and have no greater
than 13 wt % Noack volatility (as defined by ACEA A3-02 or by ACEA
B3-98).
[0088] More specifically, one aspect of this invention encompasses
lubricants comprising the inventive base oils and base stocks and
one or more performance additives, such that the lubricants
meet:
[0089] (a) the viscometric requirements of SAE 0W-40, or
[0090] (b) the viscometric requirements of SAE 0W-30, or
[0091] (c) the viscometric requirements of SAE 0W-20, or
[0092] (d) the viscometric requirements of SAE 5W-20.
[0093] The inventive base oils are also suitably used in SAE grades
wherein no VI improver is employed.
[0094] Process
[0095] The products that derive from the processes of this
invention demonstrate not only unique combinations of physical
properties, but demonstrate unique compositional properties that
distinguish and differentiate them from available commercial
products. Thus, the base stocks and base oils of this invention
derived from the processes recited herein are expected to have
unique chemical, compositional, molecular, and structural features
that uniquely define the base stocks and base oils of this
invention.
[0096] The lubricant base stocks and base oils of this invention
are made according to processes comprising the conversion of waxy
feedstocks to produce oils of lubricating viscosity having high
viscosity indices and produced in high yields. Thus, one may obtain
base stocks and base oils or base stocks having VIs of at least
130, preferably at least 135, more preferably at least 140, and
having excellent low-temperature properties. Base stocks made
according to these processes meet the requirements of a Group III
base stock and can be prepared in high yields while at the same
time possessing excellent properties such as high VI and low pour
point.
[0097] The waxy feedstock used in these processes may derive from
natural or mineral or synthetic sources. The feed to this process
mays have a waxy paraffins content of at least 50% by weight,
preferably at least 70% by weight, and more preferably at least 80%
by weight. Preferred synthetic waxy feedstocks generally have waxy
paraffins content by weight of at least 90 wt %, often at least 95
wt %, and in some instances at least 97 wt %. In addition, the waxy
feed stock used in these processes to make the base stocks and base
oils of this invention may comprise one or more individual natural,
mineral, or synthetic waxy feedstocks, or any mixture thereof.
[0098] In addition, feedstocks to these processes may be either
taken from conventional mineral oils, or synthetic processes. For
example, synthetic processes may include GTL (gas-to-liquids) or FT
(Fischer-Tropsch) hydrocarbons produced by such processes as the
Fischer-Tropsch process or the Kolbel-Englehardt process. Many of
the preferred feedstocks are characterized as having predominantly
saturated (paraffinic) compositions.
[0099] In more detail, the feedstock used in the process of the
invention are wax-containing feeds that boil in the lubricating oil
range, typically having a 10% distillation point greater than 650F
(343C), measured by ASTM D 86 or ASTM 2887, and are derived from
mineral or synthetic sources. The wax content of the feedstock is
at least about 50 wt. %, based on feedstock and can range up to 100
wt. % wax. The wax content of a feed may be determined by nuclear
magnetic resonance spectroscopy (ASTM D5292), by correlative ndM
methods (ASTM D3238) or by solvent means (ASTM D3235). The waxy
feeds may be derived from a number of sources such as natural or
mineral or synthetic. In particular, waxy feeds may include, for
example, oils derived from solvent refining processes such as
raffinates, partially solvent dewaxed oils, deasphalted oils,
distillates, vacuum gas oils, coker gas oils, slack waxes, foots
oils and the like, and Fischer-Tropsch waxes. Preferred feeds are
slack waxes and Fischer-Tropsch waxes. Slack waxes are typically
derived from hydrocarbon feeds by solvent or propane dewaxing.
Slack waxes contain some residual oil and are typically deoiled.
Foots oils are derived from deoiled slack waxes. The
Fischer-Tropsch synthetic process prepares Fischer-Tropsch waxes.
Non limiting examples of suitable waxy feedstocks include Paraflint
80 (a hydrogenated Fischer-Tropsch wax) and Shell MDS Waxy
Raffinate (a hydrogenated and partially isomerized middle
distillate synthesis waxy raffinate.)
[0100] Feedstocks may have high contents of nitrogen- and
sulfur-contaminants. Feeds containing up to 0.2 wt. % of nitrogen,
based on feed and up to 3.0 wt. % of sulfur can be processed in the
present process. Feeds having a high wax content typically have
high viscosity indexes of up to 200 or more. Sulfur and nitrogen
contents may be measured by standard ASTM methods D5453 and D4629,
respectively.
[0101] For feeds derived from solvent extraction, the high boiling
petroleum fractions from atmospheric distillation are sent to a
vacuum distillation unit, and the distillation fractions from this
unit are solvent extracted. The residue from vacuum distillation
may be deasphalted. The solvent extraction process selectively
dissolves the aromatic components in an extract phase while leaving
the more paraffinic components in a raffinate phase. Naphthenes are
distributed between the extract and raffinate phases. Typical
solvents for solvent extraction include phenol, furfural and
N-methylpyrrolidone. By controlling the solvent to oil ratio,
extraction temperature and method of contacting distillate to be
extracted with solvent, one can control the degree of separation
between the extract and raffinate phases.
[0102] Hydrotreating
[0103] For hydrotreating, the catalysts are those effective for
hydrotreating such as catalysts containing Group 6 metals (based on
the IUPAC Periodic Table format having Groups from 1 to 18), Groups
8-10 metals, and mixtures thereof. Preferred metals include nickel,
tungsten, molybdenum, cobalt and mixtures thereof. These metals or
mixtures of metals are typically present as oxides or sulfides on
refractory metal oxide supports. The mixture of metals may also be
present as bulk metal catalysts wherein the amount of metal is 30
wt. % or greater, based on catalyst. Suitable metal oxide supports
include oxides such as silica, alumina, silica-aluminas or titania,
preferably alumina. Preferred aluminas are porous aluminas such as
gamma or beta. The amount of metals, either individually or in
mixtures, ranges from about 0.5 to 35 wt. %, based on the catalyst.
In the case of preferred mixtures of groups 9-10 metals with group
6 metals, the groups 9-10 metals are present in amounts of from 0.5
to 5 wt. %, based on catalyst and the group 6 metals are present in
amounts of from 5 to 30 wt. %. The amounts of metals may be
measured by atomic absorption spectroscopy, inductively coupled
plasma-atomic emission spectrometry or other methods specified by
ASTM for individual metals.
[0104] The acidity of metal oxide supports can be controlled by
adding promoters and/or dopants, or by controlling the nature of
the metal oxide support, e.g., by controlling the amount of silica
incorporated into a silica-alumina support. Examples of promoters
and/or dopants include halogen, especially fluorine, phosphorus,
boron, yttria, rare-earth oxides and magnesia. Promoters such as
halogens generally increase the acidity of metal oxide supports
while mildly basic dopants such as yttria or magnesia tend to
decrease the acidity of such supports.
[0105] Hydrotreating conditions include temperatures of from 150 to
400.degree. C., preferably 200 to 350.degree. C., a hydrogen
partial pressure of from 1480 to 20786 kPa (200 to 3000 psig),
preferably 2859 to 13891 kPa (400 to 2000 psig), a space velocity
of from 0.1 to 10 liquid hourly space velocity (LHSV), preferably
0.1 to 5 LHSV, and a hydrogen to feed ratio of from 89 to 1780
m.sup.3/m.sup.3 (500 to 10000 scf/B), preferably 178 to 890
m.sup.3/m.sup.3.
[0106] Hydrotreating reduces the amount of nitrogen- and
sulfur-containing contaminants to levels which will not
unacceptably affect the dewaxing catalyst in the subsequent
dewaxing step. Also, there may be certain polynuclear aromatic
species which will pass through the present mild hydrotreating
step. These contaminants, if present, will be removed in a
subsequent hydrofinishing step.
[0107] During hydrotreating, less than 5 wt. % of the feedstock,
preferably less than 3 wt. %, more preferably less than 2 wt. %, is
converted to 650.degree. F. (343.degree. C.) minus products to
produce a hydrotreated feedstock whose VI increase is less than 4,
preferably less than 3, more preferably less than 2 greater than
the VI of the feedstock. The high wax contents of the present feeds
results in minimal VI increase during the hydrotreating step.
[0108] The hydrotreated feedstock may be passed directly to the
dewaxing step or preferably, stripped to remove gaseous
contaminants such as hydrogen sulfide and ammonia prior to
dewaxing. Stripping can be by conventional means such as flash
drums or fractionators.
[0109] Dewaxing Catalyst
[0110] The dewaxing catalyst may be either crystalline or
amorphous. Crystalline materials are molecular sieves that contain
at least one 10 or 12 ring channel and may be based on
aluminosilicates (zeolites) or on silicoaluminophosphates (SAPOs).
Zeolites used for oxygenate treatment may contain at least one 10
or 12 channel. Examples of such zeolites include ZSM-22, ZSM-23,
ZSM-35, ZSM-48, ZSM-57, ferrierite, ITQ-13, MCM-68 and MCM-71.
Examples of aluminophosphates containing at least one 10 ring
channel include ECR-42. Examples of molecular sieves containing 12
ring channels include zeolite beta, and MCM-68. The molecular
sieves are described in U.S. Pat. Nos. 5,246,566, 5,282,958,
4,975,177, 4,397,827, 4,585,747, 5,075,269 and 4,440,871. MCM-68 is
described in U.S. Pat. No. 6,310,265. MCM-71 and ITQ-13 are
described in PCT published applications WO 0242207 and WO 0078677.
ECR-42 is disclosed in U.S. Pat. No. 6,303,534. Preferred catalysts
include ZSM-48, ZSM-22 and ZSM-23. Especially preferred is ZSM-48.
The molecular sieves are preferably in the hydrogen form. Reduction
can occur in situ during the dewaxing step itself or can occur ex
situ in another vessel.
[0111] Amorphous dewaxing catalysts include alumina, fluorided
alumina, silica-alumina, fluorided silica-alumina and
silica-alumina doped with Group 3 metals. Such catalysts are
described for example in U.S. Pat. Nos. 4,900,707 and
6,383,366.
[0112] The dewaxing catalysts are bifunctional, i.e., they are
loaded with a metal hydrogenation component, which is at least one
Group 6 metal, at least one Group 8-10 metal, or mixtures thereof.
Preferred metals are Groups 9-10 metals. Especially preferred are
Groups 9-10 noble metals such as Pt, Pd or mixtures thereof (based
on the IUPAC Periodic Table format having Groups from 1 to 18).
These metals are loaded at the rate of 0.1 to 30 wt. %, based on
catalyst. Catalyst preparation and metal loading methods are
described for example in U.S. Pat. No. 6,294,077, and include for
example ion exchange and impregnation using decomposable metal
salts. Metal dispersion techniques and catalyst particle size
control are described in U.S. Pat. No. 5,282,958. Catalysts with
small particle size and well dispersed metal are preferred.
[0113] The molecular sieves are typically composited with binder
materials which are resistant to high temperatures which may be
employed under dewaxing conditions to form a finished dewaxing
catalyst or may be binderless (self bound). The binder materials
are usually inorganic oxides such as silica, alumina,
silica-aluminas, binary combinations of silicas with other metal
oxides such as titania, magnesia, thoria, zirconia and the like and
tertiary combinations of these oxides such as silica-alumina-thoria
and silica-alumina magnesia. The amount of molecular sieve in the
finished dewaxing catalyst is from 10 to 100, preferably 35 to 100
wt. %, based on catalyst. Such catalysts are formed by methods such
spray drying, extrusion and the like. The dewaxing catalyst may be
used in the sulfided or unsulfided form, and is preferably in the
sulfided form.
[0114] Dewaxing conditions include temperatures of from
250-400.degree. C., preferably 275 to 350.degree. C., pressures of
from 791 to 20786 kPa (100 to 3000 psig), preferably 1480 to 17339
kPa (200 to 2500 psig), liquid hourly space velocities of from 0.1
to 10 hr.sup.-1, preferably 0.1 to 5 hr.sup.-1 and hydrogen treat
gas rates from 45 to 1780 m.sup.3/m.sup.3 (250 to 10000 scf/B),
preferably 89 to 890 m.sup.3/m.sup.3 (500 to 5000 scf/B).
[0115] Hydrofinishing
[0116] At least a portion of the product from dewaxing is passed
directly to a hydrofinishing step without disengagement. It is
preferred to hydrofinish the product resulting from dewaxing in
order to adjust product qualities to desired specifications.
Hydrofinishing is a form of mild hydrotreating directed to
saturating any lube range olefins and residual aromatics as well as
to removing any remaining heteroatoms and color bodies. The post
dewaxing hydrofinishing is usually carried out in cascade with the
dewaxing step. Generally the hydrofinishing will be carried out at
temperatures from about 150.degree. C. to 350.degree. C.,
preferably 180.degree. C. to 250.degree. C. Total pressures are
typically from 2859 to 20786 kPa (about 400 to 3000 psig). Liquid
hourly space velocity is typically from 0.1 to 5 LHSV (hr.sup.-1),
preferably 0.5 to 3 hr.sup.-1 and hydrogen treat gas rates of from
44.5 to 1780 m.sup.3/m.sup.3 (250 to 10,000 scf/B).
[0117] Hydrofinishing catalysts are those containing Group 6 metals
(based on the IUPAC Periodic Table format having Groups from 1 to
18), Groups 8-10 metals, and mixtures thereof. Preferred metals
include at least one noble metal having a strong hydrogenation
function, especially platinum, palladium and mixtures thereof. The
mixture of metals may also be present as bulk metal catalysts
wherein the amount of metal is 30 wt. % or greater based on
catalyst. Suitable metal oxide supports include low acidic oxides
such as silica, alumina, silica-aluminas or titania, preferably
alumina. The preferred hydrofinishing catalysts for aromatics
saturation will comprise at least one metal having relatively
strong hydrogenation function on a porous support. Typical support
materials include amorphous or crystalline oxide materials such as
alumina, silica, and silica-alumina. The metal content of the
catalyst is often as high as about 20 weight percent for non-noble
metals. Noble metals are usually present in amounts no greater than
about 1 wt. %.
[0118] The hydrofinishing catalyst is preferably a mesoporous
material belonging to the M41S class or family of catalysts. The
M41S family of catalysts are mesoporous materials having high
silica contents whose preparation is further described in J. Amer.
Chem. Soc., 1992, 114, 10834. Examples included MCM-41, MCM-48 and
MCM-50. Mesoporous refers to catalysts having pore sizes from 15 to
100 .ANG.. A preferred member of this class is MCM-41 whose
preparation is described in U.S. Pat. No. 5,098,684. MCM-41 is an
inorganic, porous, non-layered phase having a hexagonal arrangement
of uniformly-sized pores. The physical structure of MCM-41 is like
a bundle of straws wherein the opening of the straws (the cell
diameter of the pores) ranges from 15 to 100 Angstroms. MCM-48 has
a cubic symmetry and is described for example is U.S. Pat. No.
5,198,203 whereas MCM-50 has a lamellar structure. MCM-41 can be
made with different size pore openings in the mesoporous range. The
mesoporous materials may bear a metal hydrogenation component which
is at least one of Group 8, Group 9 or Group 10 metals. Preferred
are noble metals, especially Group 10 noble metals, most preferably
Pt, Pd or mixtures thereof.
[0119] Generally the hydrofinishing will be carried out at
temperatures from about 150.degree. C. to 350.degree. C.,
preferably 180.degree. C. to 250.degree. C. Total pressures are
typically from 2859 to 20786 kPa (about 400 to 3000 psig). Liquid
hourly space velocity is typically from 0.1 to 5 LHSV (hr.sup.-1),
preferably 0.5 to 3 hr.sup.-1 and hydrogen treat gas rates of from
44.5 to 1780 m.sup.3/m.sup.3 (250 to 10,000 scf/B).
[0120] In one embodiment, the present invention is directed to a
lubricant comprising at least one base stock with a VI of at least
130 produced by a process which comprises:
[0121] (1) hydrotreating a feedstock having a wax content of at
least about 60 wt. %, based on feedstock, with a hydrotreating
catalyst under effective hydrotreating conditions such that less
than 5 wt. % of the feedstock is converted to 650.degree. F.
(343.degree. C.) minus products to produce a hydrotreated feedstock
whose VI increase is less than 4 greater than the VI of the
feedstock;
[0122] (2) stripping the hydrotreated feedstock to separate gaseous
from liquid product; and
[0123] (3) hydrodewaxing the liquid product with a dewaxing
catalyst which is at least one of ZSM-48, ZSM-57, ZSM-23, ZSM-22,
ZSM-35, ferrierite, ECR-42, ITQ-13, MCM-71, MCM-68, beta, fluorided
alumina, silica-alumina or fluorided silica alumina under
catalytically effective hydrodewaxing conditions wherein the
dewaxing catalyst contains at least one Group 9 or Group 10 noble
metal.
[0124] Another embodiment of the present invention is directed to a
lubricant comprising at least one base stock with a VI of at least
130 produced by a process which comprises:
[0125] (1) hydrotreating a lubricating oil feedstock having a wax
content of at least about 50 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to
650.degree. F. (343.degree. C.) minus products to produce a
hydrotreated feedstock to produce a hydrotreated feedstock whose VI
increase is less than 4 greater than the VI of the feedstock;
[0126] (2) stripping the hydrotreated feedstock to separate gaseous
from liquid product;
[0127] (3) hydrodewaxing the liquid product with a dewaxing
catalyst which is at least one of ZSM-22, ZSM-23, ZSM-35,
ferrierite, ZSM-48, ZSM-57, ECR-42, ITQ-13, MCM-68, MCM-71, beta,
fluorided alumina, silica-alumina or fluorided silica-alumina under
catalytically effective hydrodewaxing conditions wherein the
dewaxing catalyst contains at least one Group 9 or 10 noble metal;
and
[0128] (4) hydrofinishing the product from step (3) with a
mesoporous hydrofinishing catalyst from the M41 S family under
hydrofinishing conditions.
[0129] Another embodiment of the present invention is directed to a
lubricant comprising at least one base stock with a VI of at least
130 produced by a process which comprises:
[0130] (1) hydrotreating a lubricating oil feedstock having a wax
content of at least about 60 wt. %, based on feedstock, with a
hydrotreating catalyst under effective hydrotreating conditions
such that less than 5 wt. % of the feedstock is converted to
650.degree. F. (343.degree. C.) minus products to produce a
hydrotreated feedstock to produce a hydrotreated feedstock whose VI
increase is less than 4 greater than the VI of the feedstock;
[0131] (2) stripping the hydrotreated feedstock to separate gaseous
from liquid product;
[0132] (3) hydrodewaxing the liquid product with a dewaxing
catalyst which is ZSM-48 under catalytically effective
hydrodewaxing conditions wherein the dewaxing catalyst contains at
least one Group 9 or 10 noble metal; and
[0133] (a) Optionally, hydrofinishing the product from step (3)
with MCM-41 under hydrofinishing conditions.
[0134] Additional details concerning the processes that make the
current invention may be found in co-pending application U.S. S No.
60/416,865 which is hereby incorporated by reference in its
entirety.
[0135] Base Stocks and Base Oils
[0136] A wide range of base stocks and base oils are known in the
art. Base stocks and base oils that may be used as co-base stocks
or co-base oils in combination with the base stocks and base oils
of the present invention are natural oils, mineral oils, and
synthetic oils. These lubricant base stocks and base oils may be
used individually or in any combination of mixtures with the
instant invention. Natural, mineral, and synthetic oils (or
mixtures thereof) may be used unrefined, refined, or rerefined (the
latter is also known as reclaimed or reprocessed oil). Unrefined
oils are those obtained directly from a natural, mineral, 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 the
at least one lubricating oil property. One skilled in the art is
familiar with many purification processes. These processes include
for example solvent extraction, distillation, secondary
distillation, acid extraction, base extraction, filtration,
percolation, dewaxing, hydroisomerization, hydrocracking,
hydrofinishing, and others. Rerefined oils are obtained by
processes analogous to refined oils but using an oil that has been
previously used.
[0137] 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 stocks and base oils. Group I base stock generally
have a viscosity index of between about 80 to 120 and contains
greater than about 0.03 wt % sulfur and/or less than about 90%
saturates. Group II base stocks generally have a viscosity index of
between about 80 to 120, and contain less than or equal to about
0.03 wt % sulfur and greater than or equal to about 90% saturates.
Group III stock generally has a viscosity index greater than about
120 and contain less than or equal to about 0.03 wt % sulfur and
greater than about 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.
2TABLE 1 API Classification of Base stocks and base oils Saturates
(wt %) Sulfur (wt %) Viscosity Index Group I <90 &/or
>0.03% & .gtoreq.80 & <120 Group II .gtoreq.90 &
.ltoreq.0.03% & .gtoreq.80 & <120 Group III .gtoreq.90
& .ltoreq.0.03% & .gtoreq.120 Group IV Polyalphaolefins
(PAO) Group V All other base stocks and base oils not included in
Groups I, II, III, or IV
[0138] Base stocks and base oils may be derived from many sources.
Natural oils include animal oils, vegetable oils (castor oil and
lard oil, for example), and mineral oils. In regard to animal and
vegetable oils, those possessing favorable thermal oxidative
stability can be used. Of the natural oils, mineral oils are
preferred. Mineral oils vary widely as to their crude source, for
example, as to whether they are paraffinic, naphthenic, or mixed
paraffinic-naphthenic. Oils derived from coal or shale are also
useful in the present invention. Natural oils vary also as to the
method used for their production and purification, for example,
their distillation range and whether they are straight run or
cracked, hydrorefined, or solvent extracted.
[0139] Synthetic oils include hydrocarbon oil. Hydrocarbon oils
include oils such as polymerized and interpolymerized olefins
(polybutylenes, polypropylenes, propylene isobutylene copolymers,
ethylene-olefin copolymers, and ethylene-alphaolefin copolymers,
polymers or copolymer of hydrocarbyl-substituted olefins where
hydrocarbyl optionally contains O, N, or S, for example).
Polyalphaolefin (PAO) oil base stocks are a commonly used synthetic
hydrocarbon oil. By way of example, PAOs derived from C8, C10, C12,
C14 olefins or mixtures thereof may be utilized. See U.S. Pat. Nos.
4,956,122; 4,827,064; and 4,827,073, which are incorporated herein
by reference in their entirety.
[0140] Group III and PAO base stocks and base oils are typically
available in a number of viscosity grades, for example, with
kinematic viscosity at 100C of 4 cSt, 5 cSt, 6 cSt, 8 cSt, 10 cSt,
12 cSt, 40 cSt, 100 cSt, and higher, as well as any number of
intermediate viscosity grades. In addition, PAO base stocks and
base oils with high viscosity-index characteristics are available,
typically in higher viscosity grades, for example, with kinematic
viscosity at 100C of 100 cSt to 3000 cSt or higher. The number
average molecular weights of the PAOs, which are known materials
and generally available on a major commercial scale from suppliers
such as ExxonMobil Chemical Company, Chevron-Phillips, BP-Amoco,
and others, typically vary from about 250 to about 3000. The PAOs
are typically comprised of relatively low molecular weight
hydrogenated polymers or oligomers of alphaolefins which include,
but are not limited to, C2 to about C32 alphaolefins with C8 to
about C16 alphaolefins, such as 1-octene, 1-decene, 1-dodecene and
the like, being preferred. The preferred polyalphaolefins are
poly-1-octene, poly-1-decene and poly-1-dodecene and mixtures
thereof and mixed olefin-derived polyolefins. However, the dimers
of higher olefins in the range of C14 to C18 may be used to provide
low viscosity basestocks of acceptably low volatility. Depending on
the viscosity grade and the starting oligomer, the PAOs may be
predominantly trimers and tetramers of the starting olefins, with
minor amounts of the higher oligomers, having a viscosity range of
about 1.5 to 12 cSt. PAO base stocks and base oils may be used in
formulated lubricant composition or functional fluids either
individually or in any combination of two or more.
[0141] The PAO fluids may be conveniently made by the
polymerization of an alphaolefin in the presence of a
polymerization catalyst such as the Friedel-Crafts catalysts
including, for example, aluminum trichloride, boron trifluoride or
complexes of boron trifluoride with water, alcohols such as
ethanol, propanol or butanol, carboxylic acids or esters such as
ethyl acetate or ethyl propionate. For example the methods
disclosed by U.S. Pat. No. 4,149,178 or U.S. Pat. No. 3,382,291 may
be conveniently used herein. Other descriptions of PAO synthesis
are found in the following U.S. Pat. Nos. 3,742,082; 3,769,363;
3,876,720; 4,239,930; 4,367,352; 4,413,156; 4,434,408; 4,910,355;
4,956,122; and 5,068,487. The dimers of the C14 to C18 olefins are
described in U.S. Pat. No. 4,218,330. All of the aforementioned
patents are incorporated by reference herein in their entirety.
[0142] Other types of synthetic PAO base stocks and base oils
include high viscosity index lubricant fluids as described in U.S.
Pat. Nos. 4,827,064 and 4,827,073, which can be highly
advantageously used in combination with the base stocks and base
oils of this inventions, as well as with in the formulated
lubricant compositions or functions fluids of this same invention.
Other useful synthetic lubricating oils may also be utilized, for
example, those described in the work "Synthetic Lubricants",
Gunderson and hart, Reinhold Publ. Corp., New York, 1962, which is
incorporated in its entirety.
[0143] Other synthetic base stocks and base oils include
hydrocarbon oils that are derived from the oligomerization or
polymerization of low-molecular weight compounds whose reactive
group is not olefinic, into higher molecular weight compounds,
which may be optionally reacted further or chemically modified in
additional processes (e.g. isodewaxing, alkylation, esterification,
hydroisomerization, dewaxing, etc.) to give a base oil of
lubricating viscosity.
[0144] Hydrocarbyl aromatic base stocks and base oils are also
widely used in lubrication oils and functional fluids. In alkylated
aromatic stocks (hydrocarbyl aromatics, for example), the alkyl
substituents are typically alkyl groups of about 8 to 25 carbon
atoms, usually from about 10 to 18 carbon atoms and up to three
such substituents may be present, as described for the alkyl
benzenes in ACS Petroleum Chemistry Preprint 1053-1058, "Poly
n-Alkylbenzene Compounds: A Class of Thermally Stable and Wide
Liquid Range Fluids", Eapen et al, Phila. 1984. Tri-alkyl benzenes
may be produced by the cyclodimerization of 1-alkynes of 8 to 12
carbon atoms as described in U.S. Pat. No. 5,055,626. Other
alkylbenzenes are described in European Patent Application No.
168534 and U.S. Pat. No. 4,658,072. Alkylbenzenes are used as
lubricant basestocks, especially for low-temperature applications
(arctic vehicle service and refrigeration oils) and in papermaking
oils. They are commercially available from producers of linear
alkylbenzenes (LABs) such as Vista Chem. Co, Huntsman Chemical Co.,
Chevron Chemical Co., and Nippon Oil Co. The linear alkylbenzenes
typically have good low pour points and low temperature viscosities
and VI values greater than 100 together with good solvency for
additives. Other alkylated aromatics which may be used when
desirable are described, for example, in "Synthetic Lubricants and
High Performance Functional Fluids", Dressler, H., chap 5, (R. L.
Shubkin (Ed.)), Marcel Dekker, N.Y. 1993. Aromatic base stocks and
base oils may include, for example, hydrocarbyl alkylated
derivatives of benzene, naphthalene, biphenyls, di-aryl ethers,
di-aryl sulfides, di-aryl sulfones, di-aryl sulfoxides, di-aryl
methanes or ethanes or propanes or higher homologues, mono- or di-
or tri-aryl heterocyclic compounds containing one or more O, N, S,
or P.
[0145] The hydrocarbyl aromatics that can be used can be any
hydrocarbyl molecule that contains at least about 5% of its weight
derived from an aromatic moiety such as a benzenoid moiety or
naphthenoid moiety, or their derivatives. These hydrocarbyl
aromatics include alkyl benzenes, alkyl naphthalenes, alkyl
diphenyl oxides, alkyl naphthols, alkyl diphenyl sulfides,
alkylated bis-phenol A, alkylated thiodiphenol, and the like. The
aromatic can be mono-alkylated, dialkylated, polyalkylated, and the
like. The aromatic can be mono- or poly-functionalized. The
hydrocarbyl groups can also be comprised of mixtures of alkyl
groups, alkenyl groups, alkynyl, cycloalkyl groups, cycloalkenyl
groups and other related hydrocarbyl groups. The hydrocarbyl groups
can range from about C6 up to about C60 with a range of about C8 to
about C40 often being preferred. A mixture of hydrocarbyl groups is
often preferred. The hydrocarbyl group can optionally contain
sulfur, oxygen, and/or nitrogen containing substituents. The
aromatic group can also be derived from natural (petroleum)
sources, provided at least about 5% of the molecule is comprised of
an above-type aromatic moiety. Viscosities at 100C of approximately
3 cSt to about 50 cSt are preferred, with viscosities of
approximately 3.4 cSt to about 20 cSt often being more preferred
for the hydrocarbyl aromatic component. In one embodiment, an alkyl
naphthalene where the alkyl group is primarily comprised of
1-hexadecene is used. Other alkylates of aromatics can be
advantageously used. Naphthalene, for example, can be alkylated
with olefins such as octene, decene, dodecene, tetradecene or
higher, mixtures of similar olefins, and the like. Useful
concentrations of hydrocarbyl aromatic in a lubricant oil
composition can be about 2% to about 25%, preferably about 4% to
about 20%, and more preferably about 4% to about 15%, depending on
the application.
[0146] Other useful lubricant oil base stocks include wax isomerate
base stocks and base oils, comprising hydroisomerized waxy stocks
(e.g. waxy stocks such as gas oils, slack waxes, fuels hydrocracker
bottoms, etc.), hydroisomerized Fischer-Tropsch waxes,
Gas-to-Liquids (GTL) base stocks and base oils, and other wax
isomerate hydroisomerized base stocks and base oils, or mixtures
thereof. Fischer-Tropsch waxes, the high boiling point residues of
Fischer-Tropsch synthesis, are highly paraffinic hydrocarbons with
very low sulfur content. The hydroprocessing used for the
production of such base stocks may use an amorphous
hydrocracking/hydroisomerization catalyst, such as one of the
specialized lube hydrocracking (LHDC) catalysts or a crystalline
hydrocracking/hydroisomerization catalyst, preferably a zeolitic
catalyst. For example, one useful catalyst is ZSM-48 as described
in U.S. Pat. No. 5,075,269. Processes for making
hydrocracked/hydroisomerized distillates and
hydrocracked/hydroisomerized waxes are described, for example, in
U.S. Pat. Nos. 2,817,693; 4,975,177; 4,921,594 and 4,897,178 as
well as in British Patent Nos. 1,429,494; 1,350,257; 1,440,230 and
1,390,359. Particularly favorable processes are described in
European Patent Application Nos. 464546 and 464547. Processes using
Fischer-Tropsch wax feeds are described in U.S. Pat. No. 4,594,172
and 4,943,672. Gas-to-Liquids (GTL) base stocks and base oils,
Fischer-Tropsch wax derived base stocks and base oils, and other
wax isomerate hydroisomerized (wax isomerate) base stocks and base
oils be advantageously used in the instant invention, and may have
useful kinematic viscosities at 100C of about 3 cSt to about 50
cSt, preferably about 3 cSt to about 30 cSt, more preferably about
3.5 cSt to about 25 cSt, as exemplified by GTL4 with kinematic
viscosity of about 3.8 cSt at 100C and a viscosity index of about
138. These Gas-to-Liquids (GTL) base stocks and base oils,
Fischer-Tropsch wax derived base stocks and base oils, and other
wax isomerate hydroisomerized base stocks and base oils may have
useful pour points of about -20C or lower, and under some
conditions may have advantageous pour points of about -25C or
lower, with useful pour points of about -30C to about -40C or
lower. Useful compositions of Gas-to-Liquids (GTL) base stocks and
base oils, Fischer-Tropsch wax derived base stocks and base oils,
and wax isomerate hydroisomerized base stocks and base oils are
recited in U.S. Pat. Nos. 6,080,301; 6,090,989, and 6,165,949 for
example, and are incorporated herein in their entirety by
reference.
[0147] Gas-to-Liquids (GTL) base stocks and base oils,
Fischer-Tropsch wax derived base stocks and base oils, have a
beneficial kinematic viscosity advantage over conventional Group II
and Group III base stocks and base oils, which may be used as a
co-base stock or co-base oil with the instant invention.
Gas-to-Liquids (GTL) base stocks and base oils can have
significantly higher kinematic viscosities, up to about 20-50 cSt
at 100C, whereas by comparison commercial Group II base stocks and
base oils can have kinematic viscosities, up to about 15 cSt at
100C, and commercial Group III base stocks and base oils can have
kinematic viscosities, up to about 10 cSt at 100C. The higher
kinematic viscosity range of Gas-to-Liquids (GTL) base stocks and
base oils, compared to the more limited kinematic viscosity range
of Group II and Group III base stocks and base oils, in combination
with the instant invention can provide additional beneficial
advantages in formulating lubricant compositions. Also, the
exceptionally low sulfur content of Gas-to-Liquids (GTL) base
stocks and base oils, and other wax isomerate hydroisomerized base
stocks and base oils, in combination with the low sulfur content of
suitable olefin oligomers and/or alkyl aromatics base stocks and
base oils, and in combination with the instant invention can
provide additional advantages in lubricant compositions where very
low overall sulfur content can beneficially impact lubricant
performance.
[0148] Alkylene oxide polymers and interpolymers and their
derivatives containing modified terminal hydroxyl groups obtained
by, for example, esterification or etherification are useful
synthetic lubricating oils. By way of example, these oils may be
obtained by polymerization of ethylene oxide or propylene oxide,
the alkyl and aryl ethers of these polyoxyalkylene polymers
(methyl-polyisopropylene glycol ether having an average molecular
weight of about 1000, diphenyl ether of polyethylene glycol having
a molecular weight of about 500-1000, and the diethyl ether of
polypropylene glycol having a molecular weight of about 1000 to
1500, for example) or mono- and polycarboxylic esters thereof (the
acidic acid esters, mixed C3-8 fatty acid esters, or the C13Oxo
acid diester of tetraethylene glycol, for example).
[0149] Esters comprise a useful base stock. Additive solvency and
seal compatibility characteristics may be secured by the use of
esters such as the esters of dibasic acids with monoalkanols and
the polyol esters of monocarboxylic acids. Esters of the former
type include, for example, the esters of dicarboxylic acids such as
phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic
acid, maleic acid, azelaic acid, suberic acid, sebacic acid,
fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl
malonic acid, alkenyl malonic acid, etc., with a variety of
alcohols such as butyl alcohol, hexyl alcohol, dodecyl alcohol,
2-ethylhexyl alcohol, etc. Specific examples of these types of
esters include dibutyl adipate, di(2-ethylhexyl) sebacate,
di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate,
diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl
sebacate, etc.
[0150] Particularly useful synthetic esters are those which are
obtained by reacting one or more polyhydric alcohols, preferably
the hindered polyols (such as the neopentyl polyols e.g. neopentyl
glycol, trimethylol ethane, 2-methyl-2-propyl-1,3-propanediol,
trimethylol propane, pentaerythritol and dipentaerythritol) with
alkanoic acids containing at least about 4 carbon atoms such as C5
to C30 acids (such as saturated straight chain fatty acids
including caprylic acid, capric acid, lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, and behenic acid, or the
corresponding branched chain fatty acids or unsaturated fatty acids
such as oleic acid, or mixtures thereof).
[0151] Suitable synthetic ester components include esters of
trimethylol propane, trimethylol butane, trimethylol ethane,
pentaerythritol and/or dipentaerythritol with one or more
monocarboxylic acids containing from about 5 to about 10 carbon
atoms. Such esters are widely available commercially, for example,
the Mobil P-41 and P-51 esters (ExxonMobil Chemical Company).
[0152] Other esters may included natural esters and their
derivatives, fully esterified or partially esterified, optionally
with free hydroxyl or carboxyl groups. Such ester may included
glycerides, natural and/or modified vegetable oils, derivatives of
fatty acids or fatty alcohols.
[0153] Silicon-based oils are another class of useful synthetic
lubricating oils. These oils include polyalkyl-, polyaryl-,
polyalkoxy-, and polyaryloxy-siloxane oils and silicate oils.
Examples of suitable silicon-based oils include tetraethyl
silicate, tetraisopropyl silicate, tetra-(2-ethylhexyl)silicate,
tetra-(4-methylhexyl)silicate, tetra-(p-tert-butylphenyl) silicate,
hexyl-(4-methyl-2-pentoxy)disiloxane- , poly(methyl) siloxanes, and
poly-(methyl-2-mehtylphenyl)siloxanes.
[0154] Another class of synthetic lubricating oil is esters of
phosphorus-containing acids. These include, for example, tricresyl
phosphate, trioctyl phosphate, diethyl ester of decanephosphonic
acid.
[0155] Another type of base stocks and base oils includes polymeric
tetrahydrofurans and the like, and their derivatives where reactive
pendant or end groups are partially or fully derivatized or capped
with suitable hydrocarbyl groups which may optionally contain O, N,
or S.
[0156] The highly beneficial viscosity advantages of the base
stocks and base oils of this invention can be realized in
combination with one or more performance additives, and with the
desirable measured-to-theoretical viscosity ratios at less than
-25C, preferably at -30C or lower, being realized in the resulting
formulated lubricant compositions or functional fluids. These
lubricant compositions or functional fluids also have the unique
and highly desirable characteristic of a measured-to-theoretical
viscosity ratio of 1.2 or lower, preferably 1.16 or lower, and in
many instances more preferably 1.12 or lower. Thus the effect of
the measured-to-theoretical viscosity feature of the base stocks
and base oils of this invention is preserved even in the presence
of performance additives, leading to improved formulated lubricant
compositions or functional fluids comprising the base stocks and
base oils of this invention and one or more performance
additives.
[0157] Performance Additives
[0158] The instant invention can be used with additional lubricant
components in effective amounts in lubricant compositions, such as
for example polar and/or non-polar lubricant base oils, and
performance additives such as for example, but not limited to,
metallic and ashless oxidation inhibitors, metallic and ashless
dispersants, metallic and ashless detergents, corrosion and rust
inhibitors, metal deactivators, anti-wear agents (metallic and
non-metallic, low-ash, phosphorus-containing and non-phosphorus,
sulfur-containing and non-sulfur types), extreme pressure additives
(metallic and non-metallic, phosphorus-containing and
non-phosphorus, sulfur-containing and non-sulfur types),
anti-seizure agents, pour point depressants, wax modifiers,
viscosity index improvers, viscosity modifiers, seal compatibility
agents, friction modifiers, lubricity agents, anti-staining agents,
chromophoric agents, defoamants, demulsifiers, and others. For a
review of many commonly used additives see Klamann in Lubricants
and Related Products, Verlag Chemie, Deerfield Beach, Fla.; ISBN
0-89573-177-0, which also gives a good discussion of a number of
the lubricant additives discussed mentioned below. Reference is
also made "Lubricant Additives" by M. W. Ranney, published by Noyes
Data Corporation of Parkridge, N.J. (1973). In particular, the base
oils of this invention can show significant performance advantages
with modern additives and/or additive systems, and additive
packages that impart characteristics of low sulfur, low phosphorus,
and/or low ash to formulated lubricant compositions or functional
fluids.
[0159] Anitwear and Extreme Pressure Additives
[0160] Additional antiwear additives may be used with the present
invention. While there are many different types of antiwear
additives, for several decades the principal antiwear additive for
internal combustion engine crankcase oils is a metal
alkylthiophosphate and more particularly a metal
dialkyldithiophosphate in which the primary metal constituent is
zinc, or zinc dialkyldithiophosphate (ZDDP). ZDDP compounds
generally are of the formula Zn[SP(S)(OR.sup.1)(OR.sup.2)].sub.- 2
where R.sup.1 and R.sup.2 are C.sub.1-C.sub.18 alkyl groups,
preferably C.sub.2-C.sub.12 alkyl groups. These alkyl groups may be
straight chain or branched. For example, suitable alkyl groups
include isopropyl, 4-methyl-2-pentyl, and isooctyl. The ZDDP is
typically used in amounts of from about 0.4 wt % to about 1.4 wt. %
of the total lube oil composition, although more or less can often
be used advantageously.
[0161] However, it is found that the phosphorus from these
additives has a deleterious effect on the catalyst in catalytic
converters and also on oxygen sensors in automobiles. One way to
minimize this effect is to replace some or all of the ZDDP with
phosphorus-free antiwear additives.
[0162] A variety of non-phosphorus additives are also used as
antiwear additives. Sulfurized olefins are useful as antiwear and
EP additives. Sulfur-containing olefins can be prepared by
sulfurization or various organic materials including aliphatic,
arylaliphatic or alicyclic olefinic hydrocarbons containing from
about 3 to 30 carbon atoms, preferably 3-20 carbon atoms. The
olefinic compounds contain at least one non-aromatic double bond.
Such compounds are defined by the formula
R.sup.3R.sup.4C.dbd.CR.sup.5R where each of R.sup.3-R.sup.6 are
independently hydrogen or a hydrocarbon radical. Preferred
hydrocarbon radicals are alkyl or alkenyl radicals. Any two of
R.sup.3-R.sup.6 may be connected so as to form a cyclic ring.
Additional information concerning sulfurized olefins and their
preparation can be found in U.S. Pat. No. 4,941,984, incorporated
by reference herein in its entirety.
[0163] The use of polysulfides of thiophosphorus acids and
thiophosphorus acid esters as lubricant additives is disclosed in
U.S. Pat. Nos. 2,443,264; 2,471,115; 2,526,497; and 2,591,577.
Addition of phosphorothionyl disulfides as an antiwear,
antioxidant, and EP additives is disclosed in U.S. Pat. No.
3,770,854. Use of alkylthiocarbamoyl compounds
(bis(dibutyl)thiocarbamoyl, for example) in combination with a
molybdenum compound (oxymolybdenum diisopropylphosphorodithioate
sulfide, for example) and a phosphorus ester (dibutyl hydrogen
phosphite, for example) as antiwear additives in lubricants is
disclosed in U.S. Pat. No. 4,501,678. U.S. Pat. No. 4,758,362
discloses use of a carbamate additive to provide improved antiwear
and extreme pressure properties. The use of thiocarbamate as an
antiwear additive is disclosed in U.S. Pat. No. 5,693,598.
Thiocarbamate/molybdenum complexes such as moly-sulfur alkyl
dithiocarbamate trimer complex (R.dbd.C.sub.8-C.sub.18 alkyl) are
also useful antiwear agents. Each of the above mentioned patents is
incorporated by reference herein in its entirety.
[0164] Esters of glycerol may be used as antiwear agents. For
example, mono-, di, and tri-oleates, mono-palmitates and
mono-myristates may be used.
[0165] ZDDP is combined with other compositions that provide
antiwear properties. U.S. Pat. No. 5,034,141 discloses that a
combination of a thiodixanthogen compound (octylthiodixanthogen,
for example) and a metal thiophosphate (ZDDP, for example) can
improve antiwear properties. U.S. Pat. No. 5,034,142 discloses that
use of a metal alkyoxyalkylxanthate (nickel ethoxyethylxanthate,
for example) and a dixanthogen (diethoxyethyl dixanthogen, for
example) in combination with ZDDP improves antiwear properties.
[0166] Antiwear additives may be used in an amount of about 0.01 to
6 weight percent, preferably about 0.01 to 4 weight percent.
[0167] Viscosity Index Improvers
[0168] Viscosity index improvers (also known as VI improvers,
viscosity modifiers, or viscosity improvers) provide lubricants
with high- and low-temperature operability. These additives impart
shear stability at elevated temperatures and acceptable viscosity
at low temperatures.
[0169] Suitable viscosity index improvers include both low
molecular weight and high molecular weight hydrocarbons, polyesters
and viscosity index improver dispersants that function as both a
viscosity index improver and a dispersant. Typical molecular
weights of these polymers are between about 10,000 to 1,000,000,
more typically about 20,000 to 500,00, and even more typically
between about 50,000 and 200,000.
[0170] Examples of suitable viscosity index improvers are polymers
and copolymers of methacrylate, butadiene, olefins, or alkylated
styrenes. Polyisobutylene is a commonly used viscosity index
improver. Another suitable viscosity index improver is
polymethacrylate (copolymers of various chain length alkyl
methacrylates, for example), some formulations of which also serve
as pour point depressants. Other suitable viscosity index improvers
include copolymers of ethylene and propylene, hydrogenated block
copolymers of styrene and isoprene, and polyacrylates (copolymers
of various chain length acrylates, for example). Specific examples
include styrene-isoprene or styrene-butadiene based polymers of
about 50,000 to 200,000 molecular weight.
[0171] Viscosity index improvers may be used in an amount of about
0.01 to 15 weight percent, preferably about 0.01 to 10 weight
percent, and in some instances, more preferably about 0.01 to 5
weight percent.
[0172] Antioxidants
[0173] Antioxidants retard the oxidative degradation of base oils
during service. Such degradation may result in deposits on metal
surfaces, the presence of sludge, or a viscosity increase in the
lubricant. One skilled in the art knows a wide variety of oxidation
inhibitors that are useful in lubricating oil compositions. See,
Klamann in Lubricants and Related Products, op cite, and U.S. Pat.
Nos. 4,798,684 and 5,084,197, for example, the disclosures of which
are incorporated by reference herein in their entirety. Useful
antioxidants include hindered phenols. These phenolic antioxidants
may be ashless (metal-free) phenolic compounds or neutral or basic
metal salts of certain phenolic compounds. Typical phenolic
antioxidant compounds are the hindered phenolics which are the ones
which contain a sterically hindered hydroxyl group, and these
include those derivatives of dihydroxy aryl compounds in which the
hydroxyl groups are in the o- or p-position to each other. Typical
phenolic antioxidants include the hindered phenols substituted with
C.sub.6+ alkyl groups and the alkylene coupled derivatives of these
hindered phenols. Examples of phenolic materials of this type
2-t-butyl-4-heptyl phenol; 2-t-butyl-4-octyl phenol;
2-t-butyl-4-dodecyl phenol; 2,6-di-t-butyl-4-heptyl phenol;
2,6-di-t-butyl-4-dodecyl phenol; 2-methyl-6-t-butyl-4-heptyl
phenol; and 2-methyl-6-t-butyl-4-dodecyl phenol. Other useful
hindered mono-phenolic antioxidants may include for example
hindered 2,6-di-alkyl-phenolic proprionic ester derivatives.
Bis-phenolic antioxidants may also be advantageously used in
combination with the instant invention. Examples of ortho coupled
phenols include: 2,2'-bis(6-t-butyl-4-heptyl phenol);
2,2'-bis(6-t-butyl-4-octyl phenol); and
2,2'-bis(6-t-butyl-4-dodecyl phenol). Para coupled bis phenols
include for example 4,4'-bis(2,6-di-t-butyl phenol) and
4,4'-methylene-bis(2,6-di-t-butyl phenol).
[0174] Non-phenolic oxidation inhibitors which may be used include
aromatic amine antioxidants and these may be used either as such or
in combination with phenolics. Typical examples of non-phenolic
antioxidants include: alkylated and non-alkylated aromatic amines
such as aromatic monoamines of the formula R.sup.8R.sup.9R.sup.10N
where R.sup.8 is an aliphatic, aromatic or substituted aromatic
group, R.sup.9 is an aromatic or a substituted aromatic group, and
R.sup.10 is H, alkyl, aryl or R.sup.11S(O).sub.xR.sup.12 where
R.sup.11 is an alkylene, alkenylene, or aralkylene group, R.sup.12
is a higher alkyl group, or an alkenyl, aryl, or alkaryl group, and
x is 0, 1 or 2. The aliphatic group R.sup.8 may contain from 1 to
about 20 carbon atoms, and preferably contains from 6 to 12 carbon
atoms. The aliphatic group is a saturated aliphatic group.
Preferably, both R.sup.8 and R.sup.9 are aromatic or substituted
aromatic groups, and the aromatic group may be a fused ring
aromatic group such as naphthyl. Aromatic groups R.sup.8 and
R.sup.9 may be joined together with other groups such as S.
[0175] Typical aromatic amines antioxidants have alkyl substituent
groups of at least about 6 carbon atoms. Examples of aliphatic
groups include hexyl, heptyl, octyl, nonyl, and decyl. Generally,
the aliphatic groups will not contain more than about 14 carbon
atoms. The general types of amine antioxidants useful in the
present compositions include diphenylamines, phenyl naphthylamines,
phenothiazines, imidodibenzyls and diphenyl phenylene diamines.
Mixtures of two or more aromatic amines are also useful. Polymeric
amine antioxidants can also be used. Particular examples of
aromatic amine antioxidants useful in the present invention
include: p,p'-dioctyldiphenylamine;
t-octylphenyl-alpha-naphthylamine; phenyl-alphanaphthylamine; and
p-octylphenyl-alpha-naphthylamine.
[0176] Sulfurized alkyl phenols and alkali or alkaline earth metal
salts thereof also are useful antioxidants. Low sulfur peroxide
decomposers are useful as antioxidants.
[0177] Another class of antioxidant used in lubricating oil
compositions is oil-soluble copper compounds. Any oil-soluble
suitable copper compound may be blended into the lubricating oil.
Examples of suitable copper antioxidants include copper
dihydrocarbyl thio or dithio-phosphates and copper salts of
carboxylic acid (naturally occurring or synthetic). Other suitable
copper salts include copper dithiacarbamates, sulphonates,
phenates, and acetylacetonates. Basic, neutral, or acidic copper
Cu(I) and or Cu(II) salts derived from alkenyl succinic acids or
anhydrides are know to be particularly useful.
[0178] Preferred antioxidants include hindered phenols, arylamines,
low sulfur peroxide decomposers and other related components. These
antioxidants may be used individually by type or in combination
with one another. Such additives may be used in an amount of about
0.01 to 5 weight percent, preferably about 0.01 to 2 weight
percent.
[0179] Detergents
[0180] Detergents are commonly used in lubricating compositions. A
typical detergent is an anionic material that contains a long chain
oleophillic portion of the molecule and a smaller anionic or
oleophobic portion of the molecule. The anionic portion of the
detergent is typically derived from an organic acid such as a
sulfur acid, carboxylic acid, phosphorus acid, phenol, or mixtures
thereof. The counter ion is typically an alkaline earth or alkali
metal.
[0181] Salts that contain a substantially stochiometric amount of
the metal are described as neutral salts and have a total base
number (TBN, as measured by ASTM D2896) of from 0 to 80. Many
compositions are overbased, containing large amounts of a metal
base that is achieved by reacting an excess of a metal compound (a
metal hydroxide or oxide, for example) with an acidic gas (such as
carbon dioxide). Useful detergents can be neutral, mildly
overbased, or highly overbased.
[0182] It is desirable for at least some detergent to be overbased.
Overbased detergents help neutralize acidic impurities produced by
the combustion process and become entrapped in the oil. Typically,
the overbased material has a ratio of metallic ion to anionic
portion of the detergent of about 1.05:1 to 50:1 on an equivalent
basis. More preferably, the ratio is from about 4:1 to about 25:1.
The resulting detergent is an overbased detergent that will
typically have a TBN of about 150 or higher, often about 250 to 450
or more. Preferably, the overbasing cation is sodium, calcium, or
magnesium. A mixture of detergents of differing TBN can be used in
the present invention. Preferred detergents include the alkali or
alkaline earth metal salts of sulfates, phenates, carboxylates,
phosphates, and salicylates.
[0183] Sulfonates may be prepared from sulfonic acids that are
typically obtained by sulfonation of alkyl substituted aromatic
hydrocarbons. Hydrocarbon examples include those obtained by
alkylating benzene, toluene, xylene, naphthalene, biphenyl and
their halogenated derivatives (chlorobenzene, chlorotoluene, and
chloronaphthalene, for example). The alkylating agents typically
have about 3 to 70 carbon atoms. The alkaryl sulfonates typically
contain about 9 to about 80 carbon or more carbon atoms, more
typically from about 16 to 60 carbon atoms.
[0184] Klamann in Lubricants and Related Products, op cit discloses
a number of overbased metal salts of various sulfonic acids which
are useful as detergents and dispersants in lubricants. The book
entitled "Lubricant Additives", C. V. Smallheer and R. K. Smith,
published by the Lezius-Hiles Co. of Cleveland, Ohio (1967),
similarly discloses a number of overbased sulfonates which are
useful as dispersants/detergents.
[0185] Alkaline earth phenates are another useful class of
detergent. These detergents can be made by reacting alkaline earth
metal hydroxide or oxide (CaO, Ca(OH).sub.2, BaO, Ba(OH).sub.2,
MgO, Mg(OH).sub.2, for example) with an alkyl phenol or sulfurized
alkylphenol. Useful alkyl groups include straight chain or branched
C.sub.1-C.sub.30 alkyl groups, preferably, C.sub.4-C.sub.20.
Examples of suitable phenols include isobutylphenol,
2-ethylhexylphenol, nonylphenol, 1-ethyldecylphenol, and the like.
It should be noted that starting alkylphenols may contain more than
one alkyl substituent that are each independently straight chain or
branched. When a non-sulfurized alkylphenol is used, the sulfurized
product may be obtained by methods well known in the art. These
methods include heating a mixture of alkylphenol and sulfurizing
agent (including elemental sulfur, sulfur halides such as sulfur
dichloride, and the like) and then reacting the sulfurized phenol
with an alkaline earth metal base.
[0186] Metal salts of carboxylic acids are also useful as
detergents. These carboxylic acid detergents may be prepared by
reacting a basic metal compound with at least one carboxylic acid
and removing free water from the reaction product. These compounds
may be overbased to produce the desired TBN level. Detergents made
from salicylic acid are one preferred class of detergents derived
from carboxylic acids. Useful salicylates include long chain alkyl
salicylates, where alkyl groups have 1 to about 30 carbon atoms,
with 1 to 4 alkyl group per benzenoid nucleus, and with the metal
of the compound including alkaline earth metal. Preferred R groups
are alkyl chains of at least about C.sub.11, preferably C.sub.13 or
greater. R may be optionally substituted with substituents that do
not interfere with the detergent's function. M is preferably,
calcium, magnesium, or barium. More preferably, M is calcium.
[0187] Hydrocarbyl-substituted salicylic acids may be prepared from
phenols by the Kolbe reaction. See U.S. Pat. No. 3,595,791 for
additional information on synthesis of these compounds. The metal
salts of the hydrocarbyl-substituted salicylic acids may be
prepared by double decomposition of a metal salt in a polar solvent
such as water or alcohol. Alkaline earth metal phosphates are also
used as detergents.
[0188] Detergents may be simple detergents or what is known as
hybrid or complex detergents. The latter detergents can provide the
properties of two detergents without the need to blend separate
materials. See U.S. Pat. No. 6,034,039 for example.
[0189] Preferred detergents include calcium phenates, calcium
sulfonates, calcium salicylates, magnesium phenates, magnesium
sulfonates, magnesium salicylates and other related components
(including borated detergents). Typically, the total detergent
concentration is about 0.01 to about 6 weight percent, preferably,
about 0.1 to 4 weight percent.
[0190] In addition, non-ionic detergents may be preferably used in
lubricating compositions. Such non-ionic detergents may be ashless
or low-ash compounds, and may include discrete molecular compounds,
as well as oligomeric and/or polymeric compounds.
[0191] Dispersants
[0192] During engine operation, oil insoluble oxidation byproducts
are produced. Dispersants help keep these byproducts in solution,
thus diminishing their deposit on metal surfaces. Dispersants may
be ashless or ash-forming in nature. Preferably, the dispersant is
ashless. So called ashless dispersants are organic materials that
form substantially no ash upon combustion. For example,
non-metal-containing or borated metal-free dispersants are
considered ashless. In contrast, metal-containing detergents
discussed above form ash upon combustion.
[0193] Suitable dispersants typically contain a polar group
attached to a relatively high molecular weight hydrocarbon chain.
The polar group typically contains at least one element of
nitrogen, oxygen, or phosphorous. Typical hydrocarbon chains
contain about 50 to 400 carbon atoms.
[0194] Dispersants include phenates, sulfonates, sulfurized
phenates, salicylates, naphthenates, stearates, carbamates,
thiocarbamates, and phosphorus derivatives. A particularly useful
class of dispersants are alkenylsuccinic derivatives, typically
produced by the reaction of a long chain substituted alkenyl
succinic compound, usually a substituted succinic anhydride, with a
polyhydroxy or polyamino compound. The long chain group
constituting the oleophilic portion of the molecule which confers
solubility in the oil, is normally a polyisobutylene group. Many
examples of this type of dispersant are well known. Exemplary U.S.
patents describing such dispersants include U.S. Pat. Nos.
3,172,892; 3,2145,707; 3,219,666; 3,316,177; 3,341,542; 3,444,170;
3,454,607; 3,541,012; 3,630,904; 3,632,511; 3,787,374 and
4,234,435. Other types of dispersants are described in U.S. Pat.
Nos. 3,036,003; 3,200,107; 3,254,025; 3,275,554; 3,438,757;
3,454,555; 3,565,804; 3,413,347; 3,697,574; 3,725,277; 3,725,480;
3,726,882; 4,454,059; 3,329,658; 3,449,250; 3,519,565; 3,666,730;
3,687,849; 3,702,300; 4,100,082; 5,705,458. A further description
of dispersants is also found in European Patent Application No. 471
071. Each of the above noted patents and patent applications is
incorporated herein by reference in its entirety.
[0195] Hydrocarbyl-substituted succinic acid compounds are well
known dispersants. In particular, succinimide, succinate esters, or
succinate ester amides prepared by the reaction of
hydrocarbon-substituted succinic acid preferably having at least 50
carbon atoms in the hydrocarbon substituent, with at least one
equivalent of an alkylene amine, are particularly useful.
[0196] Succinimides are formed by the condensation reaction between
alkenyl succinic anhydrides and amines. Molar ratios can vary
depending on the polyamine. For example, the molar ratio of alkenyl
succinic anhydride to TEPA can vary from about 1:1 to about 5:1.
Representative examples are shown in U.S. Pat. Nos. 3,087,936;
3,172,892; 3,219,666; 3,272,746; 3,322,670; 3,652,616; 3,948,800;
and Canada Pat. No. 1,094,044, each of which is incorporated by
reference herein in its entirety.
[0197] Succinate esters are formed by the condensation reaction
between alkenyl succinic anhydrides and alcohols or polyols. Molar
ratios can vary depending on the alcohol or polyol used. For
example, the condensation product of an alkenyl succinic anhydride
and pentaerythritol is a useful dispersant.
[0198] Succinate ester amides are formed by condensation reaction
between alkenyl succinic anhydrides and alkanol amines. For
example, suitable alkanol amines include ethoxylated
polyalkylpolyamines, propoxylated polyalkylpolyamines and
polyalkenylpolyamines such as polyethylene polyamines. One example
is propoxylated hexamethylenediamine. Representative examples are
shown in U.S. Pat. No. 4,426,305, incorporated by reference herein
in its entirety.
[0199] The molecular weight of the alkenyl succinic anhydrides used
in the preceding paragraphs will range between about 800 and 2,500.
The above products can be post-reacted with various reagents such
as sulfur, oxygen, formaldehyde, carboxylic acids such as oleic
acid, and boron compounds such as borate esters or highly borated
dispersants. The dispersants can be borated with from about 0.1 to
about 5 moles of boron per mole of dispersant reaction product,
including those derived from mono-succinimides, bis-succinimides
(also known as disuccinimides), and mixtures thereof.
[0200] Mannich base dispersants are made from the reaction of
alkylphenols, formaldehyde, and amines. See U.S. Pat. No.
4,767,551, incorporated by reference herein in its entirety.
Process aids and catalysts, such as oleic acid and sulfonic acids,
can also be part of the reaction mixture. Molecular weights of the
alkylphenols range from 800 to 2,500. Representative examples are
shown in U.S. Pat. Nos. 3,697,574; 3,703,536; 3,704,308; 3,751,365;
3,756,953; 3,798,165; and 3,803,039, which are incorporated herein
by reference in its entirety.
[0201] Typical high molecular weight aliphatic acid modified
Mannich condensation products useful in this invention can be
prepared from high molecular weight alkyl-substituted
hydroxyaromatics or HN(R).sub.2 group-containing reactants.
[0202] Examples of high molecular weight alkyl-substituted
hydroxyaromatic compounds are polypropylphenol, polybutylphenol,
and other polyalkylphenols. These polyalkylphenols can be obtained
by the alkylation, in the presence of an alkylating catalyst, such
as BF3, of phenol with high molecular weight polypropylene,
polybutylene, and other polyalkylene compounds to give alkyl
substituents on the benzene ring of phenol having an average
600-100,000 molecular weight.
[0203] Examples of HN(R)2 group-containing reactants are alkylene
polyamines, principally polyethylene polyamines. Other
representative organic compounds containing at least one HN(R)2
group suitable for use in the preparation of Mannich condensation
products are well known and include mono- and di-amino alkanes and
their substituted analogs, e.g., ethylamine and diethanol amine;
aromatic diamines, e.g., phenylene diamine, diamino naphthalenes;
heterocyclic amines, e.g., morpholine, pyrrole, pyrrolidine,
imidazole, imidazolidine, and piperidine; melamine and their
substituted analogs.
[0204] Examples of alkylene polyamide reactants include
ethylenediamine, diethylene triamine, triethylene tetraamine,
tetraethylene pentaamine, pentaethylene hexamine, hexaethylene
heptaamine, heptaethylene octaamine, octaethylene nonaamine,
nonaethylene decamine, decaethylene undecamine, and mixtures of
such amines. Some preferred compositions correspond to formula
H2N-(Z-NH--).sub.nH, where Z is a divalent ethylene and n is 1 to
10 of the foregoing formula. Corresponding propylene polyamines
such as propylene diamine and di-, tri-, tetra-, pentapropylene
tri-, tetra-, penta- and hexaamines are also suitable reactants.
Alkylene polyamines usually are obtained by the reaction of ammonia
and dihalo alkanes, such as dichloro alkanes. Thus, the alkylene
polyamines obtained from the reaction of 2 to 11 moles of ammonia
with 1 to 10 moles of dichloro alkanes having 2 to 6 carbon atoms
and the chlorines on different carbons are suitable alkylene
polyamine reactants.
[0205] Aldehyde reactants useful in the preparation of the high
molecular products useful in this invention include aliphatic
aldehydes such as formaldehyde (such as paraformaldehyde and
formalin), acetaldehyde and aldol (b-hydroxybutyraldehyde, for
example). Formaldehyde or a formaldehyde-yielding reactant is
preferred.
[0206] Hydrocarbyl substituted amine ashless dispersant additives
are well known to those skilled in the art. See, for example, U.S.
Pat. Nos. 3,275,554; 3,438,757; 3,565,804; 3,755,433, 3,822,209,
and 5,084,197, each of which is incorporated by reference in its
entirety.
[0207] Preferred dispersants include borated and non-borated
succinimides, including those derivatives from mono-succinimides,
bis-succinimides, and/or mixtures of mono- and bis-succinimides,
wherein the hydrocarbyl succinimide is derived from a
hydrocarbylene group such as polyisobutylene having a Mn of from
about 500 to about 5000 or a mixture of such hydrocarbylene groups.
Other preferred dispersants include succinic acid-esters and
amides, alkylphenol-polyamine coupled Mannich adducts, their capped
derivatives, and other related components. Such additives may be
used in an amount of about 0.1 to 20 weight percent, preferably
about 0.1 to 8 weight percent.
[0208] Other dispersants may include oxygen-containing compounds,
such as polyether compounds, polycarbonate compounds, and/or
polycarbonyl compounds, as oligomers or polymers, ranging from low
molecular weight to high molecular weight.
[0209] Friction Modifiers
[0210] A friction modifier is any material or materials that can
alter the coefficient of friction of any lubricant or fluid
containing such material(s). Friction modifiers, also known as
friction reducers, or lubricity agents or oiliness agents, and
other such agents that change the coefficient of friction of
lubricant base oils, formulated lubricant compositions, or
functional fluids, may be effectively used in combination with the
base oils or lubricant compositions of the present invention if
desired. Friction modifiers that lower the coefficient of friction
are particularly advantageous in combination with the base oils and
lube compositions of this invention. Friction modifiers may include
metal-containing compounds or materials as well as ashless
compounds or materials, or mixtures thereof. Metal-containing
friction modifiers may include metal salts or metal-ligand
complexes where the metals may include alkali, alkaline earth, or
transition group metals. Such metal-containing friction modifiers
may also have low-ash characteristics. Transition metals may
include Mo, Sb, Sn, Fe, Cu, Zn, and others. Ligands may include
hydrocarbyl derivative of alcohols, polyols, glycerols, partial
ester glycerols, thiols, carboxylates, carbamates, thiocarbamates,
dithiocarbamates, phosphates, thiophosphates, dithiophosphates,
amides, imides, amines, thiazoles, thiadiazoles, dithiazoles,
diazoles, triazoles, and other polar molecular functional groups
containing effective amounts of 0, N, S, or P, individually or in
combination. In particular, Mo-containing compounds can be
particularly effective such as for example Mo-dithiocarbamates,
Mo(DTC), Mo-dithiophosphates, Mo(DTP), Mo-amines, Mo (Am),
Mo-alcoholates, Mo-alcohol-amides, etc.
[0211] Ashless friction modifiers may have also include lubricant
materials that contain effective amounts of polar groups, for
example hydroxyl-containing hydrocaryl base oils, glycerides,
partial glycerides, glyceride derivatives, and the like. Polar
groups in friction modifiers may include hyrdocarbyl groups
containing effective amounts of O, N, S, or P, individually or in
combination. Other friction modifiers that may be particularly
effective include, for example, salts (both ash-containing and
ashless derivatives) of fatty acids, fatty alcohols, fatty amides,
fatty esters, hydroxyl-containing carboxylates, and comparable
synthetic long-chain hydrocarbyl acids, alcohols, amides, esters,
hydroxy carboxylates, and the like. In some instances fatty organic
acids, fatty amines, and sulfurized fatty acids may be used as
suitable friction modifiers.
[0212] Useful concentrations of friction modifiers may range from
about 0.01 wt % to 10-15 wt % or more, often with a preferred range
of about 0.1 wt % to 5 wt %. Concentrations of molybdenum
containing materials are often described in terms of Mo metal
concentration. Advantageous concentrations of Mo may range from
about 10 ppm to 3000 ppm or more, and often with a preferred range
of about 20-2000 ppm, and in some instances a more preferred range
of about 30-1000 ppm. Friction modifiers of all types may be used
alone or in mixtures with the materials of this invention. Often
mixtures of two or more friction modifiers, or mixtures of friction
modifiers(s) with alternate surface active material(s), are also
desirable.
[0213] Pour Point Depressants
[0214] Conventional pour point depressants (also known as lube oil
flow improvers) may be added to the compositions of the present
invention if desired. These pour point depressant may be added to
lubricating compositions of the present invention to lower the
minimum temperature at which the fluid will flow or can be poured.
Examples of suitable pour point depressants include
polymethacrylates, polyacrylates, polyarylamides, condensation
products of haloparaffin waxes and aromatic compounds, vinyl
carboxylate polymers, and terpolymers of dialkylfumarates, vinyl
esters of fatty acids and allyl vinyl ethers. U.S. Pat. Nos.
1,815,022; 2,015,748; 2,191,498; 2,387,501; 2,655, 479; 2,666,746;
2,721,877; 2.721,878; and 3,250,715 describe useful pour point
depressants and/or the preparation thereof. Each of these
references is incorporated herein in its entirety. Such additives
may be used in an amount of about 0.01 to 5 weight percent,
preferably about 0.01 to 1.5 weight percent.
[0215] Corrosion Inhibitors
[0216] Corrosion inhibitors are used to reduce the degradation of
metallic parts that are in contact with the lubricating oil
composition. Suitable corrosion inhibitors include thiadizoles.
See, for example, U.S. Pat. Nos. 2,719,125; 2,719,126; and
3,087,932, which are incorporated herein by reference in their
entirety. Such additives may be used in an amount of about 0.01 to
5 weight percent, preferably about 0.01 to 1.5 weight percent.
[0217] Seal Compatibility Additives
[0218] Seal compatibility agents help to swell elastomeric seals by
causing a chemical reaction in the fluid or physical change in the
elastomer. Suitable seal compatibility agents for lubricating oils
include organic phosphates, aromatic esters, aromatic hydrocarbons,
esters (butylbenzyl phthalate, for example), and polybutenyl
succinic anhydride. Additives of this type are commercially
available. Such additives may be used in an amount of about 0.01 to
3 weight percent, preferably about 0.01 to 2 weight percent.
[0219] Anti-Foam Agents
[0220] Anti-foam agents may advantageously be added to lubricant
compositions. These agents retard the formation of stable foams.
Silicones and organic polymers are typical anti-foam agents. For
example, polysiloxanes, such as silicon oil or polydimethyl
siloxane, provide antifoam properties. Anti-foam agents are
commercially available and may be used in conventional minor
amounts along with other additives such as demulsifiers; usually
the amount of these additives combined is less than 1 percent and
often less than 0.1 percent.
[0221] Inhibitors and Antirust Additives
[0222] Antirust additives (or corrosion inhibitors) are additives
that protect lubricated metal surfaces against chemical attack by
water or other contaminants. A wide variety of these are
commercially available; they are referred to also in Klamann, op.
cit.
[0223] One type of antirust additive is a polar compound that wets
the metal surface preferentially, protecting it with a film of oil.
Another type of antirust additive absorbs water by incorporating it
in a water-in-oil emulsion so that only the oil touches the metal
surface. Yet another type of antirust additive chemically adheres
to the metal to produce a non-reactive surface. Examples of
suitable additives include zinc dithiophosphates, metal phenolates,
basic metal sulfonates, fatty acids and amines. Such additives may
be used in an amount of about 0.01 to 5 weight percent, preferably
about 0.01 to 1.5 weight percent. Additional types of additives may
be further incorporated into lubricant compositions or functional
fluids of this invention, and may include one or more additives
such as, for example, demulsifiers, solubilizers, fluidity agents,
coloring agents, chromophoric agents, and the like, as required.
Further, each additive type may include individual additives or
mixtures of additive.
[0224] Typical Additive Amounts
[0225] When lubricating oil compositions contain one or more of the
additives discussed above, the additive(s) are blended into the
composition in an amount sufficient for it to perform its intended
function. Typical amounts of such additives useful in the present
invention are shown in the Table 3 below.
[0226] Note that many additives, additive concentrates, and
additive packages that are purchased from manufacturers may
incorporate a certain amount of base oil solvent, or diluent, in
the formulation. Accordingly, the weight amounts in Table 3 below
are directed to the amount of active ingredient (that is the
non-solvent portion of the ingredient). The weight percents
indicated below are based on the total weight of the lubricating
oil composition. In practical applications, however, additive
components, additive concentrates, and additive packages are used
as purchased from manufactures, and may include certain amounts of
base oil solvent or diluent. The additive and formulation
components as recited in the Examples and Comparative Examples
below are used "as is" from their manufacturers or suppliers,
unless specifically noted otherwise.
3TABLE 3 Typical Amounts of Various Lubricant Oil Components
Approximate Weight Approximate Weight Compound Percent (Useful)
Percent (Preferred) Detergent 0.01-6 0.01-4 Dispersant 0.1-20 0.1-8
Friction Reducer 0.01-5 0.01-1.5 Viscosity Index Improver 0-40
0.01-30, more preferably 0.01 to 15 Antioxidant 0.01-5 0.01-2
Corrosion Inhibitor 0-5 0.01-1.5 Anti-wear Additive 0.01-6 0.01-4
Pour Point Depressant 0-5 0.01-1.5 Demulsifier 0-3 0.001-1.5
Anti-foam Agent 0.001-3 0.001-0.15 Seals Compatibility 0-3 0.01-2
Agent Base Oil Balance Balance
EXAMPLES
[0227] By controlling other non-inventive process parameters well
known to those skilled in the art, the inventive base stocks and
base oils as described by the inventive process herein can be made
over a range of low to high viscosity oils as is typical in the
industry thus allowing for blending of base stocks with a final
viscosity between those two end points. In this example, the base
stocks were manufactured using the inventive method to a higher
viscosity level of 6.6 cSt and a lower viscosity level of 4.0 cSt.
For this example, as may be seen in table 4, the Inventive Oil A
was then blended to two viscometric targets: 4.0 cSt and 5.7 cSt.
Similarly, the Inventive Oil B for this example was made from a
Fischer-Tropsch wax, blended to final viscosity targets of 4.0 cSt
and 6.3 cSt. The Comparitive Oils for this example are commercially
available base stocks blended to viscometric targets of 4 cSt, 5
cSt and 8 cSt.
[0228] Viscometric properties of Inventive base oils A and B and
the Comparative Base Oil 1 at comparable viscosity indices are
shown below (Table 4). The Kinematic Viscosities were measured by
ASTM method D445. The measured CCS viscosity were found by using
ASTM method D5293. The Theoretical Viscosity were calculated per
the Walther/MacCoull Equation as found in ASTM D341 (Appendix 1).
For this example, and as shown in FIG. 2, the linear Theoretical
Viscosity line for each oil of interest was determined from the
kinematic viscosities taken at 40C and 100C. The calculated Noack
Volatilites were made by the equation:
Noack(calc)=-6.882Ln(CCS@-35C)+67.647.
[0229] The ratio between measured and theoretical viscosity (i.e.
ratio=measured/theoretical) at -30C or below is less than 1.2 for
the Inventive Base Oils, but is higher than 1.2 for the Comparative
Base Oils at the same temperatures. Measured Noack volatility for
these base stocks and base oils is also shown, and compared to the
CALCULATED Noack volatility limit of this invention recite herein
(above). The base oils A and B clearly show measured Noack
volatility below the calculated limit, whereas the comparative base
oil 1 exceeds the calculated Noack volatility limit.
4TABLE 4 Base Stocks and Properties Comparative Base Oil Inventive
Base Oil Comp. Comp. Comp. Oil A Oil A Oil B Oil B Oil Oil Oil 4
cSt 5.7 cSt 4 cSt 6.3 cSt 14 cSt 15 cSt 18 cSt Viscosity 142 150
143 153 142 146 146 Index Kinematic Viscosity, ASTM D445 at 100 C.,
cSt 4 5.7 3.8 6.30 4.0 5.1 8.0 at 40 C., cSt 16.8 28.4 15.3 31.8
16.5 24.1 46.3 CCS Viscosity (Measured), ASTM D5293 at -30 C., cP
TLTM 2506 680 2630 1160 2270 8000 at -35 C., cP 1354 4499 1140 4670
2440 4620 THTM Theoretical Viscosity (Walther/MacCoull Eq.) at -30
C., cP 894 2439 722 2806 866 1877 6056 at -35 C., cP 1515 4364 1206
5019 1466 3329 11340 Viscosity Ratio, measured/theoretical at -30
C., cP -- 1.03 0.94 0.94 1.34 1.21 1.32 at -35 C., cP 0.89 1.03
0.94 0.93 1.66 1.39 -- Noack 15 9.7 16.4 4.5 14.8 10.5 --
Volatility, wt % CALCULATE D Noack 18 9.8 18.0 6.5 14.0 9.6 3.4
Volatility Limit, wt % (TLTM = too low to measure) (THTM = too high
to measure)
[0230] It has similarly been observed that the inventive base
stocks have a much lower scanning-brookfield viscosity (ASTM D5133)
values at low temperature (below -20C). Scanning brookfield
viscosity measurements are performed at much lower shear rates, and
slower cooling rates than the D5293 CCS technique. In the
particular example illustrate in table 4, the inventive base stocks
ratios of (measured/theoretically predicted) viscosity ranges
between 2.5 (@-20C) and 7 (@-35C), while the comparable
commercially available base stock, with similar viscosity and VI,
has a ratio ranging between 11 (@-20C), and 63 (@-25C), and its
viscosity is to high to be measured below -25C.
[0231] The viscosity-temperature performance for the Comparative
Base Oil and the Inventive Base Oil are also demonstrably different
over a range of base oil viscosity, as measured by kinematic
viscosity at 100C. At comparable kinematic viscosity at 100C and
Noack volatility, it is evident that the Inventive Base Oil has
superior (i.e. lower) low-temperature viscosity than that of
comparative base oil 1, at temperatures such as, for example, -30C
and -35C (Table 5 and FIG. 4).
5TABLE 5 Base Oil CCS Low-Temperature Viscosity at Comparable
Kinematic Viscosity and Volatility Inventive Comparative Base Oil A
Base Oil 1 4-6.6 cSt Mixtures 4-8 cSt Mixtures CCS @ - CCS @ - CCS
@ - CCS @ - KV @ 100 C, 30 C 35 C 30 C 35 C cSt cP cP cP cP 4.0 857
1445 1524 2798 4.6 1282 2214 2032 3713 6.0 2830 5120 3600 6700
[0232] The wax derived base stocks that are used in the examples of
formulated lubricant compositions of this invention span a
kinematic viscosity range from 3.9 cSt to 6.8 cSt at 100C. Suitable
combinations of these base stocks and base oils satisfy the base
oil descriptions for the inventive base oil compositions recited
herein.
[0233] For inventive lubricant composition examples 1, 2 and 3, all
formulations are made with the same additive package, which meets
the engine test requirements of ACEA A3-02/B3-98, added to the same
inventive base oils as detailed in the first example. The
comparative examples were made with the same additive package
blended into the same commercially available base oils as in the
first example. The formulations for this example were developed
such that the corresponding inventive/comparative pairs would have
the same base oil viscosity, and have similar Noack volatility
performance. All formulations are blended as lubricant products
targeting SAE 0W-30 grade viscometric specifications. The Inventive
base oils are compared to Comparative Base Oil 1. Both the
Inventive base oils and the Comparative Base Oil 1 have viscosity
indices>140, and pour points<-15C. Three different viscosity
modifiers are used.
[0234] The Inventive base oils provide a formulated lubricant
composition which meets the requirements of volatility defined by
ACEA A3-O.sub.2/B3-98, and the CCS viscosity at -35C as currently
defined by SAE J300 (Table 1). The Comparative Base Oil 1, while
meeting the same limits for volatility, is significantly higher in
CCS viscosity and is well above the maximum CCS viscosity limit for
the SAE 0W-30 grade specification (Table 6).
6TABLE 6 Inventive and Comparative Examples Inventive Examples
Comparative Examples 1 2 3 CE. 1 CE. 2 CE. 3 Formulated Lubricant
Composition (wt %) Inventive Base Oil A (4 & 6.6 cSt blend)
71.1 80.4 Inventive Base Oil B (4 & 6 cSt blend) 66.3
Comparative Base Oil 1 (4 & 5 cSt blend) 71.1 80.4 66.3
Performance Additive Package 1 13.7 13.7 13.7 13.7 13.7 13.7
Viscosity Modifier 1 (SICP 15 15 block) Viscosity Modifier 2 (SICP)
5.7 5.7 Viscosity Modifier 3 (SICP 20 20 block) Pour Point
Depressant 0.2 0.2 0.2 0.2 Properties SAE OW-30 Limit Kinematic
Viscosity @ 100 C., 9.3-12.5 10.6 10.8 12.3 10.5 10.7 12.3 cSt cSt
CCS Viscosity @ -35 C., cP 6200 cP 5464 5724 5980 7656 8674 9840
max Noack Volatility, wt % 13 wt % 12 12 12 11 11 12 max (SICP
block = styrene-isoprene block copolymer) (SICP = styrene-isoprene
copolymer)
[0235] The beneficial property of inventive base stocks and base
oils to advantageously lower CCS viscosity of formulated lubricant
compositions and products extends across a wide temperature range,
not only below -30C, but also significantly above -30C. For
example, the table below demonstrates that there is a CCS viscosity
benefit (i.e. lower CCS viscosity) at -20C and at -25C for a
formulation using Inventive base oil relative to a comparable
formulation using Comparative Base Oil 1 instead. The CCS viscosity
benefit difference for formulated lubricant based on Inventive base
oil (Example 4) compared to Comparative Base Oil 1 (Comparative
Example 4) becomes greater as the temperature decreases (Table
7).
7TABLE 7 CCS Viscosity Change and Formulated Lubricants Inventive
Comparative Example Example 4 CE. 4 Formulated Lubricant
Composition (wt %) Inventive Base Oil A 50 (4 & 6.6 cSt blend)
Comparative Base Oil 1 50 (5 cSt) Group 1 Base Stock 13.8 13.8
Performance Additive Package 2 23 23 Viscosity Modifier 1 (SICP)
13.2 13.2 Properties Kinematic Viscosity @ 100 C, cSt 13.62 13.65
CCS Viscosity @ -20 C, cP 2870 3200 CCS Viscosity @ -25 C, cP 5130
6280
* * * * *
References