U.S. patent application number 14/000405 was filed with the patent office on 2014-01-09 for lubricant composition.
This patent application is currently assigned to DOW GLOBAL TECHNOLOGIES LLC. The applicant listed for this patent is Martin R. Greaves, Jochem Kersbulck, Daniele Vinci. Invention is credited to Martin R. Greaves, Jochem Kersbulck, Daniele Vinci.
Application Number | 20140011723 14/000405 |
Document ID | / |
Family ID | 45879047 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140011723 |
Kind Code |
A1 |
Vinci; Daniele ; et
al. |
January 9, 2014 |
LUBRICANT COMPOSITION
Abstract
Provided is a lubricant composition derived from renewable
materials and that is useable in cold weather conditions and
exhibits oxidative stability. The lubricant composition comprises a
polymer of Formula (I), wherein R and p are as described in this
specification. ##STR00001##
Inventors: |
Vinci; Daniele; (Gent,
BE) ; Kersbulck; Jochem; (Terneuzen, NL) ;
Greaves; Martin R.; (Baar, CH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Vinci; Daniele
Kersbulck; Jochem
Greaves; Martin R. |
Gent
Terneuzen
Baar |
|
BE
NL
CH |
|
|
Assignee: |
DOW GLOBAL TECHNOLOGIES LLC
Midland
MI
|
Family ID: |
45879047 |
Appl. No.: |
14/000405 |
Filed: |
March 12, 2012 |
PCT Filed: |
March 12, 2012 |
PCT NO: |
PCT/US2012/028733 |
371 Date: |
August 20, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61468625 |
Mar 29, 2011 |
|
|
|
Current U.S.
Class: |
508/465 ;
554/227 |
Current CPC
Class: |
C10M 107/20 20130101;
C10M 107/34 20130101; C10M 2209/109 20130101; C10M 105/38 20130101;
C10N 2030/10 20130101; C10M 145/38 20130101; C10N 2070/00 20130101;
C10M 129/74 20130101; C10N 2020/02 20130101; C10M 2209/109
20130101; C10M 2209/105 20130101 |
Class at
Publication: |
508/465 ;
554/227 |
International
Class: |
C10M 107/20 20060101
C10M107/20 |
Claims
1. A lubricant composition comprising a polymer represented by the
formula I: ##STR00005## wherein p is 2 or 3 or fraction between 2
and 3, R at each occurrence is independently a group of the
formula: ##STR00006## n is an integer from 6 to 13, one of R.sup.1
and R.sup.2 is H and one is linear or branched C.sub.1-C.sub.7
alkyl, and m is an integer or fraction from 2 to 5.
2. (canceled)
3. The lubricant composition of claim 1 wherein R.sup.1 is H and
R.sup.2 is methyl.
4. The lubricant composition of claim 1 wherein m is an integer or
fraction from 2 to 3.
5. The lubricant composition of claim 1 wherein n is an integer
from 7 to 9.
6. The lubricant composition of claim 1 wherein the polymer
exhibits a viscosity at 40 degrees Celsius (V40) of at least 30
centistokes and a viscosity at 100 degrees Celsius (V100) of at
least 7 centistokes.
7. The lubricant composition of claim 1 wherein the polymer
exhibits a viscosity at 40 degrees Celsius (V40) of at least 50
centistokes and a viscosity at 100 degrees Celsius (V100) of at
least 9 centistokes.
8. The lubricant composition of claim 1 wherein the polymer
exhibits a pour point of -40 degrees Celsius or lower without a
pour point depressant.
9. A method of lubricating an apparatus, comprising providing a
lubricant composition according to claim 1.
10. A method for making the polymer of claim 1, the method
comprising: (a) reacting a polyol and an alkylene oxide compound
under alkoxylation conditions to form an alkoxylate; (b)
esterifying the alkoxylate of step (a) with a fatty acid or its
alkyl ester under esterification conditions to form the polymer of
claim 1.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from provisional
application Ser. No. 61/468,625, filed Mar. 29, 2011, which is
incorporated herein by reference in its entirety.
BACKGROUND
[0002] The invention relates generally to lubricant compositions
and to methods of their preparation and use. More particularly, the
invention relates to lubricant compositions that may be prepared
from renewable sources and that exhibit a combination of favorable
viscosity, stability, and pour point characteristics.
[0003] "Bio-lubricants," or lubricants based upon renewable
resources such as seed oils and vegetable oils rather than from
petroleum or natural gas, represent a small, but growing segment of
total global lubricants demand. Natural esters (for example, canola
oil) and synthetic esters can be used to formulate bio-lubricants
that conform to the requirements of the European Eco-label
(European Commission 2005/360/EC). These formulations must contain
certain minimum levels of renewable carbon atoms in the formulation
in order to meet the EC requirements. As an example, hydraulic
fluids require a minimum level of renewable carbons of at least 50
percent.
[0004] To be useful in a broad array of applications, biolubricants
need to meet a number of technical performance criteria. In
particular, materials that show acceptable viscosity at low and
high temperatures, and have high viscosity index values (preferably
greater than 140) as well as good cold weather properties, and
contain a high percentage of renewable carbons, have generally been
elusive. As a consequence, many biolubricants are not optimal for
use in applications where these performance criteria are needed
including, for instance, applications where very low temperatures
may be experienced, such as with outdoor mobile equipment.
[0005] In addition to viscosity and cold weather performance
criteria, another desirable feature is oxidative stability. That
is, the lubricant composition, when it contains an antioxidant,
exhibits a viscosity that remains substantially stable even when
the composition is subjected to prolonged heating.
STATEMENT OF INVENTION
[0006] We have now discovered new lubricant compositions that may
at least partially be based on renewable materials and that also
exhibit favorable low and high temperature viscosity, exhibit high
viscosity indices, and exhibit very low pour points.
Advantageously, therefore, the lubricants are well suited for use
under a variety of temperature conditions, including temperatures
at -40.degree. C. and lower. In addition, the compositions exhibit
excellent oxidative stability, experiencing little viscosity
fluctuation even after prolonged heating.
[0007] In one aspect, there is provided a lubricant composition
comprising a polymer represented by the formula I:
##STR00002##
[0008] wherein p is an integer or fraction from 1 to 5, R at each
occurrence is independently a group of the formula:
##STR00003##
[0009] n is an integer from 6 to 13, one of R.sup.1 and R.sup.2 is
H and one is linear or branched C.sub.1-C.sub.7 alkyl, and m is an
integer or fraction from 2 to 5.
[0010] In another aspect, there is provided a method for
lubricating an apparatus, comprising providing a lubricant
composition as described herein.
[0011] In another aspect, there is provided a method for making the
polymer of formula I, the method comprising: (a) reacting a polyol
and an alkylene oxide compound under alkoxylation conditions to
form an alkoxylate; and (b) esterifying the alkoxylate of step (a)
with a fatty acid or its alkyl ester under esterification
conditions.
DETAILED DESCRIPTION
[0012] Unless otherwise indicated, numeric ranges, for instance as
in "from 2 to 10," are inclusive of the numbers defining the range
(e.g., 2 and 10).
[0013] Unless otherwise indicated, ratios, percentages, parts, and
the like are by weight.
[0014] In some embodiments, p in the polymer of formula I is a
fraction between 1 and 5, alternatively it is a fraction between 2
and 5, or alternatively it is a fraction between 2 and 3. In some
embodiments, p is 2. In some embodiments, p is 3.
[0015] In some embodiments, R.sup.1 in the polymer of formula I is
H and R.sup.2 is methyl.
[0016] In some embodiments, m is an integer or fraction from 2 to
3. In some embodiments, m is a fraction between 2 and 3.
[0017] In some embodiments, n is an integer from 7 to 9. In some
embodiments, n is 8.
[0018] Polymers of formula I may be prepared by a process
comprising an alkoxylation step and an esterification step. In the
alkoxylation step, a polyol may be mixed with an alkoxylation
catalyst, such as aqueous potassium hydroxide, flushed with an
inert gas, and heated under reduced pressure in order to remove
water from the mixture. When the desired water content is reached,
e.g., 1500 ppm or less, the pressure may be increased and an
alkylene oxide introduced to the reaction mixture. Typically, the
addition and reaction may be conducted at elevated temperature,
such as 120 to 140.degree. C. Following a digestion time, e.g., 4-6
hours, the alkoxylated product may be isolated.
[0019] The polyol of the alkoxylation step may be a polyglycerine
compound or mixture of compounds represented by the formula A:
##STR00004##
wherein p in each compound is an integer from 1 to 5, preferably 2
to 3. Various polyglycerines of the foregoing formula are available
from renewable sources. For instance, polyglycerines in which p is
2 (diglycerine) and p is 3 (triglycerine) and their mixtures are
available from bio-glycerine.
[0020] The alkylene oxide is preferably propylene oxide or butylene
oxide, more preferably it is propylene oxide.
[0021] In the esterification step, the alkoxylate, a catalyst such
as titanium (IV) isopropoxide, and a fatty acid or a fatty acid
derivative, such as or its alkyl ester (e.g., its methyl ester),
anhydride, or chloride are mixed and heated, for example to 150 to
170.degree. C., under an inert gas, to effect the esterification
reaction. Vacuum may be applied during the reaction in order to
remove formed water or alcohol byproduct. The temperature may be
further facilitated by increasing the temperature and/or reducing
the pressure. Following sufficient time for the reaction to occur,
e.g., 1-3 hours, the product mixture may be cooled and the
esterified product isolated.
[0022] Suitable fatty acids for the esterification step include,
for example, octanoic acid, nonanoic acid, decanoic acid,
undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic
acid, or pentadecanoic acid. In some embodiments, the methyl ester
of the foregoing acids is preferred. In some embodiments, the fatty
acid is decanoic acid or its methyl ester, methyl decanoate. The
foregoing acids and esters may be obtained from a variety of
renewable sources, such as natural esters (e.g. palm oil, castor
oil, rapeseed oil and soybean oil).
[0023] As noted above, the polymers of formula I may be prepared
from renewable polyols and fatty acids (or derivatives) and may be
produced to contain at least 50 percent renewable carbons,
alternatively at least 60 percent renewable carbons, or
alternatively at least 70 percent renewable carbons. As a result,
in some embodiments, lubricant composition which comprise the
polymers may conform to the requirements of the European Eco-label
(European Commission 2005/360/EC).
[0024] Polymers of formula I exhibit highly favorable pour points,
making them useful in very cold weather environments. In some
embodiments, the polymers exhibit a pour point of -40.degree. C. or
less, alternatively -45.degree. C. or less, or alternatively
-50.degree. C. or less (when measured in the absence of pour point
depressants such as polyakylene-methacrylates or styrene/maleic
anhydride interpolymers). Pour point may be measured in accord with
American Society for Testing and Materials (ASTM) D97-87.
[0025] Polymers of formula I also exhibit favorable viscosity
profiles over a wide temperature range. In some embodiments, the
polymers exhibit a kinematic viscosity at 40.degree. C. (V40) of at
least 30 cSt (centistokes) alternatively at least 40 cSt,
alternatively at least 50 cSt, alternatively at least 55 cSt, or
alternatively at least 60 cSt. In some embodiments, the polymers of
formula I exhibit a kinematic viscosity at 100.degree. C. (V100) of
at least 7 cSt, alternatively at least 8 cSt, alternatively at
least 9 cSt, alternatively at least 10 cSt, or alternatively at
least 12 cSt. In some embodiments, the polymers of formula I
exhibit a V40 of at least 50 cSt and a V100 of at least 9 cSt.
Viscosity (kinematic) may be measured using a Stabinger viscometer
in accord with ASTM D7042.
[0026] Additionally compositions of the invention demonstrate
favorable oxidative stability profiles. That is, when the
composition includes a polymer of formula I and an anti-oxidant, it
exhibits a narrow kinematic viscosity change when heated at
elevated temperature for extended periods of time. Oxidative
stability may be measured using ASTM D2893B. According to the
method, the formula I polymer plus an antioxidant are heated to
121.degree. C. in dry air for 13 days. The kinematic viscosity of
the fluid at 100.degree. C. (KV100) before and after the test is
recorded according to ASTM D7042 and the percentage viscosity
change is recorded.
[0027] In some embodiments of the invention, the compositions
exhibit a kinematic viscosity change at 100.degree. C., using the
foregoing test, of 8 percent or less, alternatively 6 percent or
less, or alternatively 4.3 percent or less.
[0028] Lubricant compositions of the invention have utility as, for
example, hydraulic fluids. Hydraulic fluids are used in a variety
of apparatus common to industrial segments including mining, steel,
die-casting, and food processing, as well as forestry and marine
equipment, and outdoor mobile equipment. Furthermore, such
lubricant compositions also have potential utility in the
automotive segment as, for example, engine oils, transmission
fluids, compressor fluids, and gear oils or as components of such
oils or fluids. Skilled artisans who work with lubricant
compositions readily understand other suitable end use applications
for the lubricant compositions of the present invention.
[0029] Some embodiments of the invention will now be described in
detail in the following Examples.
EXAMPLES
[0030] Polymers for evaluation in the examples may be prepared as
follows.
Alkoxylation Procedure:
[0031] Alkoxylations are carried out on a 10 liter stainless steal
reactor which is temperature controlled via an external
thermostatic control unit containing silicone oil. The oxide dosing
system is controlled by weight and limited by a maximum pressure in
the reactor of 4.5 bar.
[0032] Polyol and catalyst (45 wt % KOH in water) are charged into
the reactor at 50.degree. C. In order to limit discoloration due to
oxidation reactions the reactor is flushed five times with
nitrogen. The stirrer is started and the speed is set to 500 rpm.
Next the reactor content is brought to 100.degree. C. and vacuum is
applied (30 mbar) in order to remove the water from the
initiator/catalyst mixture. The oxide feeding bomb is filled with
propylene oxide (PO). After typically 1 hour flashing, samples are
taken from the mixture in the reactor and water content is
determined by titration. When the water content reaches the desired
value (typically 1500 ppm), water flashing is stopped and the
reactor pressure is brought to 1.2 bars (with nitrogen). The
temperature of the mixture in the reactor is increased to
130.degree. C. After reaching the reaction temperature, the oxide
feed is started. The maximum gauge pressure in the reactor is 4.5
bars. After a digest time of 5 hours (or more) the reactor content
is cooled to 60.degree. C. Magnesium silicate (MagSil) is added (to
adsorb the KOH catalyst) and stirred for approx 30 min. Typically 8
grams of MagSil is charged into the reactor for every gram of KOH
catalyst. Next the mixture is taken out of the reactor and filtered
using a buchner funnel and paper filter (type 604 from Scheicher
& Schuell) until the product is clear.
Esterification Procedure:
[0033] The setup includes a glass reactor with a temperature
control unit, a stirrer, nitrogen sparger/blanket and sampling port
Attached to the reactor is a dean stark that allows separating the
entrainer phase from the by-product. Between the reactor and the
Dean-Stark, a distillation column (Vigreux column) can be placed to
improve distillation efficiency. A second collecting cold trap is
placed after the condenser to increase volatiles recovery when
being removed. A vacuum pump is connected to the system and is used
to aid volatiles removal process from the reaction mixture.
[0034] All raw materials and the catalyst titanium (IV)
iso-propoxide are placed in the reactor and the mixture is heated
to 160.degree. C. on a nitrogen atmosphere. The vacuum pump is set
to 100 mBar an then the system switched from nitrogen to vacuum.
Methanol formed during the reaction is collected in the Dean-Stark
receiver. Once the theoretical amount of methanol is collected or
no more methanol is condensing in the receiver, the vacuum is set
to 15 mBars end excess ester is removed from the mixture. To
facilitate removal the temperature is set to 190.degree. C. and the
mixture is left under reduced pressure for 1 hour. After completion
of this step the mixture is cooled to approximately 70.degree. C.
and then filtered over magnesium silicate.
Viscosity and Pour Point Performance
[0035] Table 1 lists polymers, starting materials, and various of
their properties, which may be prepared substantially as described
above. Products numbers 1-4 are representative of the invention,
whereas product numbers C1-C4 are comparative examples and not of
the invention.
TABLE-US-00001 TABLE 1 Summary of Properties Product No. 1 2 3 4 C1
C2 C3 C4 Starter PG2 PG2 PG3 PG2 TMP IP200 PG2 PG2 Mol's PO 12 9 11
9 6 -- 9 9 Fatty acid C10 sat C10 sat C10 sat C10 sat C10 sat C10
sat C16/C18 Oleic (or its sat methyl ester) V40 (cSt) 68.5 56.1
78.3 62.1 42.9 13.5 71.7 69.0 V100 (cSt) 11.8 9.96 12.9 10.5 8.01
3.57 12.1 13.4 Viscosity 171 167 167 161 162 156 168 202 Index Pour
point -52 -56 -53 -53 -56 -50 -28 -33 (.degree. C.) Renewable 56 63
64 63 56 62 73 74 Carbon content (%) PG2 = diglycerine (formula I
cmpd where p = 2); PG = triglycerine (formula I cmpd where p = 3),
TMP = trimethylopropane; IP = polypropylene glycol (average mol
weight 200 g/mole); PO = propylene oxide; C10 sat = decanoic acid
or its methyl ester; C16 sat = hexadecanoic acid or its methyl
ester; C18 sat = octadecanoic acid or its methyl ester; Oleic =
oleic acid or its methyl ester
[0036] As can be seen from the data in the Table, products
according to the invention (numbers 1-4) provide a combination of
excellent pour point characteristics and high viscosity indices. In
contrast, Formulations C3 and C4 show high pour points and
formulation C2 shows a low viscosity at 40.degree. C. which is not
practical for use in many lubricant applications.
Oxidation Test Performance
[0037] The oxidation stabilities of some of the compositions
described above are examined using ASTM D2893B. To each polymer is
added 1% IRGANOX.RTM. L57 and 0.5% IRGANOX.RTM. L101 as
anti-oxidants (both available from BASF). A summary of the
oxidation method is as follows.
[0038] The test lubricant (300 ml) in a borosilicate glass tube is
heated to 121.degree. C. in dry air for 13 days. The kinematic
viscosity of the fluid at 100.degree. C. (KV100) before and after
the test is recorded according to ASTM D7042 and the percentage
viscosity change is recorded. Desirable fluids are those which show
a viscosity change of less than 6%.
[0039] Results for various compositions are shown in Table 2. Two
reference fluids are also evaluated in the test (in addition to the
comparative compositions).
TABLE-US-00002 TABLE 2 Oxidation performance using ASTM D2893B %
Viscosity change Product No. after 13 days 2 3.1 3 4.3 4 3.5 C1 8.9
C3 4.5 C4 168 Canola oil - reference 516 Trimethylolpropane
trioleate (SYNATIVE 305 TMP-05 from Cognis)- reference
[0040] Table 2 shows that compositions of the invention (numbers
2-4) exhibit excellent oxidation stability and a viscosity change
of <6%. In contrast C1 and C4 and the two reference fluids show
higher values.
* * * * *