Note: Descriptions are shown in the official language in which they were submitted.
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WO 96/17909 PCT/US95/16224
BIODEGRADABLE BRANCHED SYNTHETIC ESTER BASE STOCKS
AND LUBRICANTS FORMED THEREFROM
The present invention relates generally to the use of branched synthetic
esters to improve the cold-flow properties and dispersant solubility of
biodegradable lubricant base stocks without loss of biodegradation or
lubrication.
At least 60% biodegradation (as measured by the Modified Sturm test) can be
achieved with branching along the chains of the acyl and/or alcohol portions
of the
to ester. These branched synthetic esters are particularly useful in the
formation of
biodegradable lubricants in two-cycle engine oils, catapult oils, hydraulic
fluids,
drilling fluids, water turbine oils, greases, compressor oils, and other
industrial and
engine applications where biodegradability is needed or desired.
BACKGROUND OF THE INVENTION
The interest in developing biodegradable lubricants for use in applications
which result in the dispersion of such lubricants into waterways, such as
rivers,
oceans and lakes, has generated substantial interest by both the environmental
2o community and lubricant manufacturers. The synthesis of a lubricant which
maintains its cold-flow properties and additive solubility without loss of
biodegradation or lubrication would be highly desirable.
Base stocks for biodegradable lubricant applications (e.g., two-cycle engine
oils, catapult oils, hydraulic fluids, drilling fluids, water turbine oils,
greases and
compressor oils) should typically meet five criteria: ( 1 ) solubility with
dispersants
and other additives such as polyamides; (2) good cold flow properties (such
as,
less than -40°C pour point; less than 7500 cps at -25°C); (3)
sufficient
biodegradability to off set the low biodegradability of any dispersants and/or
other
3o additives to the formulated lubricant; (4) good lubricity without the aid
of wear
additives; and (5) high flash point (greater than 260°C, flash and fire
points by
COC (Cleveland Open Cup) as measured by ASTM test number D-92).
The Organization for Economic Cooperation and Development (DECD)
issued draft test guidelines for degradation and accumulation testing in
December
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1979. The Expert Group recommended that the following tests should be used to
determine the "ready biodegradability" of organic chemicals: Modified DECD
Screening Test, Modified MITI Test (I), Closed Bottle Test, Modified Storm
Test
and the Modified AFNOR Test. The Group also recommended that the following
"pass levels" of biodegradation, obtained within 28 days, may be regarded as
good
evidence of "ready-biodegradability": (Dissolved Organic Carbon (DOC)) 70%;
(Biological Oxygen Demand (BOD)) 60%; (Total Organic Carbon (TOD)) 60%;
(COz) 60%; and (DOC) 70%, respectively, for the tests listed above. Therefore,
the "pass level" of biodegradation, obtained within 28 days, using the
Modified
1o Storm Test is at least (COz) 60°l°.
Since the main purpose in setting the test duration at 28 days was to allow
sufficient time for adaptation of the micro-organisms to the chemical (lag
phase),
this should not allow compounds which degrade slowly, after a relatively short
15 adaptation period, to pass the test. A check on the rate of biodegradation
therefore should be made. The "pass level" of biodegradation (60%) must be
reached within 10 days of the start of biodegradation. Biodegradation is
considered to have begun when 10% of the theoretical COz has evolved. That is,
a
readily biodegradable fluid should have at least a 60% yield of COz within 28
days,
2o and this level must be reached within 10 days of biodegradation exceeding
10%.
This is known as the "10-Day Window."
The DECD guideline for testing the "ready biodegradability" of chemicals
under the Modified Storm test (DECD 301B, adopted May 12, 1981)
25 involves the measurement of the amount of COZ
produced by the test compound which is measured and expressed as a percent of
the theoretical COz (TCOz) it should have produced calculated from the carbon
content of the test compound. Biodegradability is therefore expressed as a
percentage of TCOz. The Modified Storm test is run by spiking a chemically
3o defined liquid medium, essentially free of other organic carbon sources,
with the
test material and inoculated with sewage micro-organisms. The CO~ released is
trapped as BaC03. ARer reference to suitable blank controls, the total amount
of
COz produced by the zest compound is determined for the test period and
calculated as the percentage of total COz that the test material could have
3s theoretically produced based on carbon composition. See G. van der Waal and
D.
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3
Kenbeek, "Testing, Application, and Future Development of Environmentally
Friendly Ester Based Fluids", ,lQurnal of Svmthetic Lubrication, Vol. 10,
Issue No.
1, April 1993, pp. 67-83.
s One base stock in current use today is rapeseed oil (i.e., a triglyceride of
fatty acids, e.g., 7 % saturated C,Z to C,a acids, 50% oleic acid, 36%
linoleic acid
and 7% linolenic acid, having the following properties: a viscosity at
40°C of 47.8
cSt, a pour point of 0°C, a flash point of 162°C and a
biodegradability of 85% by
the Modified Stutm test. Although it has very good biodegradability, its use
in
1o biodegradable lubricant applications is limited due to its poor low
temperature
properties and poor stability.
Unless they are sufficiently low in molecular weight, esters synthesized
from both linear acids and linear alcohols tend to have poor low temperature
is properties. Even when synthesized from linear acids and highly branched
alcohols,
such as polyol esters of linear acids, high viscosity esters with good low
temperature properties can be difficult to achieve. In addition,
pentaerythritol
esters of linear acids exhibit poor solubility with dispersants such as
poiyamides,
and trimethylolpropane esters of low molecular weight (i.e., having a carbon
2o number less than 14) linear acids do not provide su~cient lubricity. 'This
lower
quality of lubriaty is also seen with adipate estas of branched alcohols.
Since low
molecular weight linear esters also have tow viscosities, some degree of
branching
is required to build viscosity while maintaining good cold flow properties.
When
both the alcohol and acid portions of the ester are highly branched, however,
such
25 as with the case of polyol esters of highly branched oxo acids, the
resulting
molecule tends to exhibit poor biodegradation as measured by the Modified
Sturm
test (OECD Test No. 301B).
In an article by handles and Wright, "Environmentally Considerate Ester
3o Lubricants for the Automotive and Engineering Industries", Journal of
Synthetic
L~~rication. Vol. 9-2, pp. 145-161, it was stated that the main features which
slow
or reduce microbial breakdown are the extent of branching, which reduces ~i-
oxidation, and the degree to which ester hydrolysis is inhibited. The negative
effect on biodegradability due to branching along the carbon chain is further
35 discussed in a book by RD. Swisher, "Surfactant Biodegradation", el
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Dekker. Inc., Second Edition, 1987, pp. 415-417. In his book, Swisher stated
that ,
"The results clearly showed increased resistance to biodegradation with
increased
branching... Although the effect of a single methyl branch in an otherwise
linear
molecule is barely noticeable, increased resistance [to biodegradation] with
increased branching is generally observed, and resistance becomes
exceptionally
great when quaternary branching occurs at all chain ends in the molecule." The
negative effect of alkyl branching on biodegradability was also discussed in
an
article by N.S. Battersby, S.E. Pack , and R.J. Watkinson, "A Correlation
Between
the Biodegradability of Oil Products in the CEC-L-33-T-82 and Modified Sturm
to Tests", Chemosphere, 24( 12), pp. 1989-2000 ( 1992).
Initially, the poor biodegradation of branched polyol esters was believed to
be a consequence of the branching and, to a lesser extent, to the insolubility
of the
molecule in water. However, recent work by the present inventors has shown
that
the non-biodegradability of these branched esters is more a function of steric
hindrance than of the micro-organism's inability to breakdown the tertiary and
quaternary carbons. Thus, by relieving the steric hindrance around the ester
linkage(s), biodegradation can more readily occur with branched esters. _
2o Branched synthetic polyol esters have been used extensively in non-
biodegradable applications, such as refrigeration lubricant applications, and
have
proven to be quite effective if 3,5,5-trimethylhexanoic acid is incorporated
into the
molecule at 25 molar percent or greater. However, trimethylhexanoic acid is
not
biodegradable as determined by the Modified Sturm test (OECD 301B), and the
incorporation of 3,5,5-trirnethylhexanoic acid, even at 25 molar percent,
would
drastically lower the biodegradation of the polyol ester due to the quaternary
carbons contained therein.
Likewise, incorporation of trialkyl acetic acids (i.e., neo acids) into a
polyol
3o ester produces very useful refrigeration lubricants. These acids do not,
however,
biodegrade as determined by the Modified Sturm test (OECD 301B) and cannot be
used to produce polyol esters for biodegradable applications. Polyol esters of
all
branched acids can be used as refrigeration oils as well. However, they do not
rapidly biodegrade as determined by the Modified Sturm Test (DECD 301B) and,
therefore, are not desirable for use in biodegradable applications.
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Although polvol esters made from purely linear C~ and C,o acids for
refrigeration applications would be biodegradable under the Modified Sturm
test,
they would not work as a lubricant in hydraulic or two-cycle engine
applications
because the viscosities would be too low and wear additives would be needed.
It
is extremely difficult to develop a lubricant base stack which is capable of
exhibiting all of the various properties required for biodegradable lubricant
applications, i.e., high viscosity, low pour point, oxidative stability and
biodegradability as measured by the Modified Sturm test.
1o U.S. Patent No. 4,826,633 (Carr et al.), which issued on May 2, 1989,
discloses a synthetic ester lubricant base stock formed by reacting at least
one of
trimethylolpropane and monopentaervthritol with a mixture of aliphatic mono-
carboxylic acids. The mixture of acids includes suaight-chain acids having
from 5
to 10 carbon atoms and an iso-acid having from 6 to 10 carbon atoms,
preferably
15 iso-nonanoic acid (i.e., 3,5,5-trimethylhexanoic acid). This base stock is
mixed
with a conventional ester lubricant additive package to form a lubricant
having a
viscosity at 99°C (210°F) of at least 5.0 centistokes and a pour
point of at least as
low as -54°C (-65°F). This lubricant is particularly usefi~l in
gas ttubine engines.
The Carr et al. patent differs firm the present invention for two reasons.
Firstly, it
2o preferably uses as its branched acid 3,5,5-trimethylhexanoic acid which
contains a
quaternary carbon in every acid molecule. The incorporation of quaternary
carbons within the 3,5,5-trimethylhexanoic acid inhibits biodegradation of the
polyol ester product. Also, since the lubricant according to Carr et al.
exhibits
high stability, as measured by a high pressure differential scanning
calorimeter
25 (F~'DSC), i.e., about 35 to 65 minutes, the micro-organisms cannot pull
them
apart. Conversely, the lubricant according to the present invention is low in
stability, i.e., it has a HPDSC reading of about I2-17 minutes. The lower
stability
allows the micro-organisms to attack the carbon-to-carbon bonds about the
polyol
structure and effectively cause the ester to biodegrade. One reason that the
30 , lubricant of the present invention is lower in stability is the fact that
no more than
10% of the branched acids used to form the lubricant's ester base stock
contain a
quaternary carbon.
Therefore, the present inventors have discovered that highly biodegradable
35 lubricants using biode_Qradable base stocks with good cold flow properties,
good
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4
solubility with dispersants, and good lubricity can be achieved by
incorporating
branched acids into the ester molecule. The branched acids used in accordance
with the present invention are needed to build viscosity and the multiple
isomers in
these acids are helpful in attaining low temperature properties. That is, the
branched acids allow the chemist to build viscosity without increasing
molecular .
weight. Furthermore, branched biodegradable lubricants provide the following
cumulative advantages over all linear biodegradable lubricants: ( 1 )
decreased pour
point; (2) increased solubilities of other additives; (3) increased
detergency/dispersancy of the lubricant oil; and (4) increased oxidative
stability in
1o hydraulic fluid and catapult oil applications.
The data compiled by the present inventors and set forth in the examples to
follow show that all of the above listed properties can be best met with
biodegradable lubricants formulated with biodegradable synthetic ester base
stocks
15 which incorporate both highly branched acids and linear acids.
SUMMARY OF THE INVENTION
A biodegradable synthetic base stock which preferably comprises the
20 reaction product of a branched or linear alcohol having the general formula
R(OI~", wherein R is an aliphatic or cyclo-aliphatic group having from about 2
to
20 carbon atoms (preferably an alkyl) and n is at least 2 and up to about 10;
and
mixed acids comprising about 30 to 80 molar %, more preferably about 35 to 55
mole %, of a linear acid having a carbon number (i.e., carbon number means the
25 total number of carbon atoms in either the acid or alcohol as the case may
be) in
the range between about C~ to C,2, more preferably about C, to Coo; and about
20
to 70 molar %, more preferably about 35 to 55 mole %, of at least one branched
acid having a carbon number in the range between about CS to C13, more
preferably about C~ to C lo; wherein the ester exhibits the following
properties: at
30 least 60% biodegradation in 28 days as measured by the Modified Sturm test;
a
pour point of less than -25°C; and a viscosity of less than 7500 cps at
-25°C.
In the most preferred embodiment, it is desirable to have a branched acid
comprising multiple isomers, preferably more than 3 isomers, most preferably
more
35 than S isomers. The linear acid is preferably an alkyl mono- or di-
carboxylic acid
CA 02208219 2005-03-02
7
having the general formula RCOOH, wherein R is an n-alkyl having between about
4 to 11 carbon atoms, more preferably between about 7 to 10 carbon atoms. It
is
also preferable that no more than 10% of the branched acids used to form the
biodegradable synthetic ester base stock contain a quaternary carbon.
These biodegradable synthetic base stocks are particularly useful in the
formulation of biodegradable lubricants, such as, two-cycle engine oils,
biodegradable catapult oils, biodegradable hydraulic fluids, biodegradable
drilling
fluids, biodegradable water ttubine oils, biodegradable greases,
biodegradable,
to compressor oils, functional fluids and other industrial and enstine
applications
where biodeQradabiliry is needed or desired.
The formulated biodegradable lubricants according to the present invention
preferably comprise about 60-99 % by weight of at least one biodegradable
15 lubricant synthetic base stock discussed above, about 1 to 20 % by weight
lubricant additive package, and about 0 to 20 % of a solvent.
In one embodiment of the invention, the ester of the biodegradable base
2o stock exhibits a flash point Cleveland Open Cup of at least 175°C.
In a further embodiment of the invention, the branched acid is
predominantly a doubly branched or an alpha branched acid having an average
25 branching per molecule in the range of between about 0.3 to about 1.9.
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7a
DESCRIPTION OF THE PREFE$~D EMBODIMENTS
The branched synthetic ester base stock used in the formulation of various
biodegradable lubricants and oils in accordance with the present invention is
preferably formed from the reaction product of technical grade
pentaerythritol,
which comprises between about 86-92°t° mono-pentaerythritol, 6-
12% di-
pentaerythritol and 1-3% tri-pentaerythritol, with approximately 30.70 molar
9b Cs
aad C,o linear acids ("C810" linear acids) and approximately 30-70 molar % iso-
C,
(e.g., Cekanoic 8) branched acids.
Neopentyl glycol (NPG) can be totally esterified with 2-ethylhexanoic acid
or an iso-C8 acid and still maintain about 90% biodegradation as measured by
the
Modified Sturm test. After two branched acids have been added to a branched
polyol, the ester linkaees begin to become crowded around the quaternary
carbon
of the branched alcohol. Additional branched acids added to the branched
alcohol
begin to lower the biodegradation of the molecule such that by the fourth
addition
of a branched acid to the branched alcohol, the biodeeradation of the
resulting
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8
molecule drops from about 80% to less than 15% biodegradation as measured by
the Modified Sturm test.
Introduction of linear acids into the molecule relieves the steric crowding
around the quaternary carbon of the branched alcohol. Thus, by having two
branched acids and two linear acids on pentaerythritol, for example, the
enzymes
have access to the ester linkages, and the first stage of biodegradation,
i.e., the
hydrolysis of the ester, can occur. In each of the pentaerythritol esters, the
hydroxyl groups are esterified with the various branched and linear acids.
to
ALCOHOLS
Among the alcohols which can be reacted with the branched and linear
acids of the present invention are, by way of example, polyols (i.e.,
polyhydroxyl
compounds) represented by the general fo=cnula:
15 R(OH)"
wherein R is any aliphatic or cyclo-aliphatic hydrocarbyl group (preferably an
alkyl) and n is at least 2. The hydrocarbyl group may contain from about 2 to
about 20 or more carbon atoms, and the hydrocarbyl group may also contain
substituents such as chlorine, nitrogen and/or oxygen atoms. The polyhydroxyl
2o compounds generally will contain from about 2 to about 10 hydroxyl groups
and
more preferably from about 2 to about 6 hydroxy groups. The polyhydroxy
compound may contain one or more oxyalkylene groups and, thus, the
polyhydroxy compounds include compounds such as polyetherpolyols. The
number of carbon atoms (i.e., carbon number) and number of hydroxy groups
(i.e.,
25 hydroxyl number) contained in the polyhydroxy compound used to form the
carboxylic esters may vary over a wide range.
The following alcohols are particularly useful as polyols: neopentyl glycol,
2,2-dimethylol butane, trimethylol ethane, trimethylol propane, trimethylol
butane,
3o mono-pentaerythritol, technical grade pentaenrthritol, di-pentaerythritol,
ethylene
glycol, propylene glycol and polyalkylene glycols (e.g., polyethylene glycols,
polypropylene glycols, polybutylene glycols, etc., and blends thereof such as
a
polymerized mixture of ethylene glycol and propylene glycol).
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R
The preferred branched or linear alcohols are selected from the group
consisting of technical grade pentaerythritol, mono-pentaerythritol, di-
pentaerythritol, neopentylglycol, trimethylol propane, trimethylol ethane and
propylene glycol, 1,4-butanediol, sorbitol and the like, and 2-
methylpropanediol.
The most preferred alcohol is technical grade (i.e., 88% mono, 10% di and 1-2%
tri) pentaerythritol.
BRANCHED ACIDS
The branched acid is preferably a mono-carboxylic acid which has a carbon
to number in the range between about Cs to C13, more preferably about C7 to
C,o
wherein methyl branches are preferred. The preferred branched acids are those
wherein less than or equal to 10% of the branched acids contain a quaternary
carbon. The mono-carboxylic acid is at least one acid selected from the group
consisting of 2-ethylhexanoic acids, isoheptanoic acids, iso-octanoic acids,
iso-
nonanoic acids, iso-decanoic acids, and oc-branched acids. The most preferred
branched acid is iso-octanoic acids, e.g., Cekanoic 8 acid.
It is desirable to have a branched acid comprising multiple isomers,-
preferably more than 3 isomers, most preferably more than S isomers.
LINEAR ACIDS
The preferred mono- and/or di-carboxylic linear acids are any linear,
saturated alkyl carboxylic acids having a carbon number in the range between
about 5 to 12, preferably 7 to 10. The most preferred linear acids are mono-
carboxylic acids.
Some examples of linear acids include n-heptanoic, n-octanoic, n-decanoic
and n-nonanoic acids. Selected diacids include adipic, azelaic, sebacic and
dodecanedioic acids. For the purpose of modifying the viscosity of the
resultant
3o ester product, up to 20 wt.% of the total acid mixture can consist of
linear di-
acids.
BIfJDEGRADABLE LUBRICANTS
The branched synthetic ester base stock can be used in the formulation of
biodegradable lubricants together with selected lubricant additives. The
additives
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~D
listed below are typically used in such amounts so as to provide their normal
attendant functions. Typical amounts for individual components are also set
forth
below. The preferred biodegradable lubricant contains approximately 80% or
greater by weight of the basestock and 20% by weight of any combination ~of
the
following additives:
(Broad) (Preferred)
Wt.% Wt.%
Viscosity Index Improver 1-12 1-4
to Corrosion Inhibitor 0.01-3 0.01-1.5
Oxidation Inhibitor 0.01-5 0.01-1.5
Dispersant 0.1-10 0.1-5
Lube Oil Flow Improver 0.01-2 0.01-1.5
Detergents and Rust Inhibitors0.01-6 0.01-3
Pour Point Depressant 0.01-1.5 0.01-1.5
Antifoaming Agents 0.001-0.1 0.001-0.01
Antiwear Agents 0.001-5 0.001-1.5
Seal Swellant 0.1-8 0.1-4
Friction Modifiers 0.01-3 0.01-1.5
2o Biodegradable Synthetic Ester Base Stock >_80% >_80%
When other additives are employed, it may be desirable, although not
necessary, to prepare additive concentrates comprising concentrated solutions
or
dispersions of the dispersant (in concentrated amounts hereinabove described),
together with one or more of the other additives (concentrate when
constituting an
additive mixture being referred to herein as an additive package) whereby
several
additives can be added simultaneously to the base stock to form the
lubricating oil
composition. Dissolution of the additive concentrate into the lubricating oil
may
be facilitated by solvents and by mixing accompanied with mild heating, but
this is
3o not essential. The concentrate or additive-package will typically be
formulated to
contain the dispersant additive and optional additional additives in proper
amounts
to provide the desired concentration in the final formulation when the
additive
package is combined with a predetermined amount of base lubricant or base
stock.
Thus, the biodegradable lubricants according to the present invention can
employ
CA 02208219 2005-03-02
typically up to about 20 wt.% of the additive package with the remainder being
biodegradable ester base stock andlor a solvent.
All of the weight percents expressed herein (unless otherwise indicated) are
based on active ingredient (A.L) content of the additive, and/or upon the
total
weight of any additive-package, or formulation which will be the sum of the
A.I.
weight of each additive plus the weight of total oil or diluent.
Examples of the above additives for use in biodegradable lubricants are set
to forth in the following documents: U.S.
Patent No. 5,306,313 (Emery et al.), which issued on April 26, 1994; U.S.
Patent
No. 5,312,554 (Waddoups et al.), which issued on May 17, 1994; U.S. Patent No.
5,328,624 (Chung), which issued July 12, 1994; an article by Benfaremo and
Liu,
"Crankcase Engine Oil Additives", Lubricati~. Texaco Inc., pp. 1 -7; and an
is article by Liston, "Engine Lubricam Additives What They are and How They
Function", Lubrication En~neerinq, May 1992, pp. 389-397.
Viscosity modifiers impart high and low temperature operability to she
lubricating oil and permit it to remain shear stable at elevated temperatures
and
Zo also exhibit acceptable viscosity or fluidity at low temperatures. These
viscosity
modifiers are generally high molecular weight hydrocarbon polymers including
polyesters. The viscosity modifiers may also be derivatized to include other
properties or functions, such as the addition of dispersancy properties.
Representative examples of suitable viscosity modi5ers are any of the types
known
i5 to the art including polyisobutylene, copolymers of ethylene and propylene,
polymethacrylates, methacrylate copolymers, copolymers of an unsaturated
dicarboxylic acid and vinyl compound, interpolymers of styrene and acrylic
esters,
and partially hydrogenated copolymers of styrenelisoprene, styrene/butadiene,
and
isopreneJbutadiene, as well as the partially hydrogenated homopolymers of
3o butadiene and isoprene.
Corrosion inhibitors, also known as anti-corrosive agents, reduce the
degradation of the metallic parts comacted by the lubricating oil composition.
Illustrative of corrosion inhibitors are phosphosulfurized hydrocarbons and
the
35 products obtained by reaction of a phosphosulfurized hydrocarbon with an
alkaline
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n
earth metal oxide or hydroxide, preferably in the presence of an alkylated
phenol or
of an alkylphenol thioester, and also preferably in the presence of an
alkylated
phenol or of an alkylphenol thioester, and also preferably in the presence of
carbon
dioxide. Phosphosulfurized hydrocarbons are prepared by reacting a suitable
hydrocarbon such as a terpene, a heavy petroleum fraction of a CZ to C6 olefin
polymer such as polyisobutylene, with from 5 to 30 wt.% of a sulfide of
phosphorus for'/z to 15 hours, at temperatures in the range of about 66 to
about
316°C. Neutralization of the phosphosulfurized hydrocarbon may be
erected in
the manner taught in U.S. Patent No. 1,969,324.
Oxidation inhibitors, or antioxidants, reduce the tendency of mineral oils to
deteriorate in service which deterioration can be evidenced by the products of
oxidation such as sludge and varnish-like deposits on the metal surfaces, and
by
viscosity growth. Such oxidation inhibitors include alkaline earth metal salts
of
alkyl-phenolthioesters having preferably CS to C12 alkyl side chains, e.g.,
calcium
nonylphenol sulfide, barium octylphenylsulfide, dioctylphenylamine,
phenylalphanaphthylamine, phosphosulfurized or sulfurized hydrocarbons, etc.
Friction modifiers serve to impart the proper friction characteristics to
2o lubricating oil compositions such as automatic transmission fluids.
Representative
examples of suitable friction modifiers are fatty acid esters and amides,
molybdenum complexes of polyisobutenyl succinic anhydride-amino alkanols,
glycerol esters of dimerized fatty acids, alkane phosphoric acid salts,
phosphonate
with an oleamide, S-carboxyalkylene hydrocarbyl succinimide,
N(hydroxylalkyl)alkenylsuccinamic acids or succinimides, di-(lower alkyl)
phosphites and epoxides, and alkylene oxide adduct of phosphosulfurized N-
(hydroxyalkyl)alkenyl succinimides. The most preferred friction modifiers are
succinate esters, or metal salts thereof, of hydrocarbyl substituted succinic
acids or
anhydrides and thiobis-alkanols.
Dispersants maintain oil insolubles, resulting from oxidation during use, in
suspension in the fluid thus preventing sludge flocculation and precipitation
or
deposition on metal pans. Suitable dispersants include high molecular weight
alkyl
succinimides, the reaction product of oil-soluble polyisobutylene succinic
CA 02208219 2005-03-02
i~
anhydride with ethylene amines such as tetraethviene pentamine and borated
sans
thereof.
Pour point depressants, otherwise known as tube oil flow improvera, lower
s the temperature at which the fluid will flow or can be poured. Such
additives are
well known. Typical of those additives which usually optimize the low
temperature fluidity of the fluid are Cs to C" dialkylfumarate vinyl acetats
copolymers, polymethacrylates, and wax naphthalene. Foam control can be
provided by an amifoamant of the poiysiloxane type, e.g., silicone oil and
to polydimethyl siloxane.
Antiwear agents, as their name implies. reduce wear of metal pans
Representative of conventional antiwear agents are zinc dialkyldithiophosphate
and
zinc diaryldithiophosphate.
Antifoam agents are used for controlling foam in the lubricant. Foam
comrol can be provided by an antifoatnant of the high molecular weight
dimethylsiloxanes and polyethers. Some examples of the polysiloxane type
antifoamant are silicone oil and polydimethyl siloxane.
Detergents and metal rust inhibitors include the metal salts of sulphonic
acids, alkyl phenols, sulfurized alkyl phenols, alkyl salicylates,
naphthenates and
other oil soluble mono- and di-carboxylic acids. Highly basic (viz. overbased)
metal salts, such as highly basic alkaline earth metal sulfonates (especially
Ca and
Mg salts) are frequently used as detergents.
Seal swellants include mineral oils of the type that provoke swelling of
engine seals, including aliphatic alcohols of 8 to 13 carbon atoms such as
trideryl
alcohol, with a preferred seal swellattt being characterized as an oil-
soluble,
3o saturated, aliphatic or aromatic hydrocarbon ester of from 10 to 60 carbon
atoms
and 2 -4 linkages, e.g., dihexyl phthalate, as are described in U.S. Patent
No.
3,974,081.
CA 02208219 2005-03-02
B10DEGRADABLE TW(1-CYCLE ENGINE O1<LS
The branched synthetic ester base stock can be used in the formulation of
biodegradable two-cycle engine oils together with selected lubricant
additives.
The preferred biodegradable two-cycle engine oil is typically formulated using
the
biodegradable synthetic ester base stock formed according to the present
invention
together with any conventional two-cycle engine oil additive package. The
additives listed below are typically used in such amounts so as to provide
their
normal attendant functions. The additive package may include, but is not
limited
to, viscosity index improvers, corrosion inhibitors, oxidation inhibitors,
coupling
1o agents, dispersants, extreme pressure agents, color stabilizers,
surfactants, diluents,
detergents and rust inhibitors, pour point depressants, antifoaming agents,
and
antiwear agents.
The biodegradable two-cycle engine oil according to the present invention
can employ typically about 75 to 85% base stock, about 1 to 5% solvent, with
the
remainder comprising an additive package.
Examples of the above additives for use in biodegradable lubricants are set
forth in the following documents: U.S.
2o Psient No. 4,663,063 {Davis), which issued on May 5, 1987; U.S. Patent No.
5,330,667 (Tiffany, III et al.), which issued on July 19, 1994; U.S. Patent
No.
4,740,321 (Davis et al.), which issued on April 26, 1988; U.S. Patent No.
5,321,172 (Alexander et al.), which issued on June 14, 1994; and U.S. Patent
No.
5,049,291 (Miyaji et al.), which issued on September 17, 1991.
B10DEGRADABLE CATAPULT OTLS
Catapults are instruments used on aircraft carriers at sea to eject the
aircraft off of the carrier. The branched synthetic ester base stock can be
used in
the formulation of biodegradable catapult oils together with selected
lubricant
3o additives. The preferred biodegradable catapult oil is typically formulated
using
the biodegradable synthetic ester base stock formed according to the present
im~ention together with any conventional catapult oil additive package. The
additives listed below are typically used in such amounts so as to provide
their
normal attendant functions. The additive package may include, but is not
limited
to, viscosity index improvers, corrosion inhibitors, oxidation inhibitors,
extreme
CA 02208219 2005-03-02
I?
pressure agents. color stabilizers. detereents and rust inhibitors,
antifoaming
agents, antiwear agents. and friction modifiers.
The biodegradable catapult oil according to the present invention can
employ typically about 90 to 99°~o base stock, with the remainder
comprising an
additive package.
Biodegradable catapult oils preferably include conventional corrosion
inhibitors and rust inhibitors. If desired, the catapult oils may contain
other
1o conventional additives such as antifoam agents. antiwear agents, other
amioxidants, e~etreme pressure agents, friction modifiers and other hydrolytic
stabilizers. These additives are disciosed in Klamann. "Lubricants and Related
Products", Verlae Chemie, Deerfield Beach, FL, 1984.
IS
BIODEGRADABLE HYDRAULIC FLUIDS
The branched synthetic ester base stock caa be used in the formulation of
biodegradable hydraulic fluids together with selected lubricant additives. The
preferred biodegzadable hydraulic fluids are typically formulated using the
2o biodegradable synthetic ester base stock formed according to the present
invention
together with any conventional hydraulic fluid additive package. The additives
listed below are typically used in such amounts so as to provide their normal
attendant functions. The additive package may include, but is not limited to,
viscosity index improvers, corrosion inhibitors, boundary lubrication agents,
2s demulsifiers, pour poim depressants, and antifoaming agents.
The biodegradable hydraulic fluid according to the present invention can
employ typically about 90 to 99% base stock, with the remainder comprising an
additive package.
Other additives are disclosed in U.S. Patent No. 4,783,274 (3okinen et al.),
which issued on November 8, 1988.
3~
CA 02208219 2005-03-02
I~
BIODEGRADABLE DRILLING FLUIDS
The branched synthetic ester base stock can be used in the formulation of
biodegradable drilling fluids together with selected lubricant additives. The
preferred biodegradable drilling fluids are typically formulated using the
biodegradable synthetic ester base stock foamed according to the present
invention
together with any conventional drilling fluid additive package. The additives
lined
below are typically used in such amounts so as to provide their normal
attendant
functions. The additive package may include, but is not limited to, viscosity
index
improvers, corrosion inhibitors, wettinging agents, water loss improving
agems,
~o bactericides, and drill bit lubricants.
The biodegradable drilling fluid according to the present invention can
employ typically about 60 to 90% base stock and about 5 to 25% solvent, with
the
ranainder comprising an additive package. See U.S. Patent No. 4,382,002
15 (Walker et al), which issued on May 3, 1983.
Suitable hydrocarbon solvents include: mineral oils, particularly those
paraffin base oils of good oxidation stability with a boiling range of from
200-
20 400°C such as Mentor 28~, sold by F.aecon Chemical Americas,
Houston, Texas;
diesel and gas oils; and heavy aromatic naphtha.
BIODEGRADABLE WATER TURBINE OILS
The branched synthetic ester base stock can be used in the formulation of
25 biodegradable water turbine oils together with selected lubricant
additives. The
preferred biodegradable water turbine oil is typically formulated using the
biodegradable synthetic ester base stock formed according to the present
invention
together with any conventional water turbine oil additive package. The
additives
listed below are typically used in such amounts so as to provide their normal
3o attendant functions. The additive package may include, but is not limited
to,
viscosity index improvers, corrosion inhibitors, oxidation inhibitors,
thickeners,
dispersants, anti-emulsifying agents, color stabilizers, detergents and rust
inhibitors, and pour point depressants.
CA 02208219 1997-06-06
WO 96/17909 PCT/US95116224
~7
The biodegradable water turbine oil according to the present invention can
employ typically about 65 to 75% base stock and about 5 to 30% solvent, with
the
remainder comprising an additive package, typically in the range between about
0.01 to about 5.0 weight percent each, based on the total weight of the
composition.
BIODEGRADABLE GREASES
The branched synthetic ester base stock can be used in the formulation of
biodegradable greases together with selected lubricant additives. The main
1o ingredient found in greases is the thickening agent or gellant and
differences in
grease formulations have often involved this ingredient. Besides, the
thickener or
gellants, other properties and characteristics of greases can be influenced by
the
particular lubricating base stock and the various additives that can be used.
15 The preferred biodegradable greases are typically formulated using the
biodegradable synthetic ester base stock formed according to the present
invention
together with any conventional grease additive package. The additives listed
below are typically used in such amounts so as to provide their normal
attendant
functions. The additive package may include, but is not limited to, viscosity
index
2o improvers, oxidation inhibitors, extreme pressure agents, detergents and
rust
inhibitors, pour point depressants, metal deactivators, antiwear agents, and
thickeners or gellants.
The biodegradable grease according to the present invention can employ
25 typically about 80 to 95% base stock and about 5 to 20% thickening agent or
gellant, with the remainder comprising an additive package.
Typically thickening agents used in grease formulations include the alkali
metal soaps, clays, polymers, asbestos, carbon black, silica gels, polyureas
and
3o aluminum complexes. Soap thickened greases are the most popular with
lithium
and calcium soaps being most common. Simple soap greases are formed from the
alkali metal salts of long chain fatty acids with lithium 12-hydroxystearate,
the
predominant one formed from 12-hydroxystearic acid, lithium hydroxide
monohydrate and mineral oil. Complex soap greases are also in common use and
35 comprise metal salts of a mixture of organic acids. One typical complex
soap
CA 02208219 2005-03-02
1~
grease found in use today is a complex lithium soap grease prepared from 12-
hydroxystearic acid, lithium hydroxide monohydrate, azelaic acid and mineral
oil.
The lithium soaps are described and exemplified in many patents including U.S.
Patent No. 3,758,407 (darting), which issued on September 11, 1973; U.S.
Patent
No. 3,791,973 (Gilani), which issued on February 12, 1974; and U.S. Patent No.
3,929,651 (hurray), which issued on December 30, 1975,
and U.S. Patent No. 4,392,967 (Alexander), which issued on July 12, 1983.
1o A description of the additives used in greases may be found in Boner,
"Modern Lubricating Greases", 1976, Chapter 5,
as well as additives listed above in the other biodegradable products.
BIODEGRADABLE COMPRESSOR OILS
The branched synthetic ester base stock can be used in the formulation of
biodegradable compressor oils together with selected lubricant additives. The
preferred biodegradable compressor oil is typically formulated using the
biodegradable synthetic ester base stock formed according to the present
invention
together with any conventional compressor oil additive package. The additives
i0 listed below are typically used in such amounts so as to provide their
normal
attendant functions. The additive package may include, but is not limited to,
oxidation inhibitors, additive solubilizers, rust inhibitors/metal
passivators,
demuisifying agents, and amiwear agents.
i5 The biodegradable compressor oil according to the present invention can
etaploy typically about 80 to 99% base stock and about 1 to I S% solvent, with
the
remainder comprising an additive package.
The additives for compressor oils are also set forth in U.S. Patent No.
30 5,156,759 (Culpon, Jr.), which issued on October 20, 1992,
EXAMPLE 1
The following are conventional ester base stocks which do not exhibit
35 satisfactory properties for use as biodegradable lubricants. The properties
listed in
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WO 96/17909 PCT/US95/16224
if
- Tables 1 and 2 were determined as follows. Pour Point was determined using
ASTM # D-97. Brookfield Viscosity at -25°C was determined using ASTM #
D-
2983. Kinematic viscosity (@ 40 and 100°C) was determined using ASTM #
D-
445. Viscosity index (VI) was determined using ASTM # D-2270.
Biodegradation was determined using the Modified Sturm test (OECD Test No.
301B). Solubility with dispersant was determined by blending the desired
ratios
and looking for haze, cloudiness, two-phases, etc. Engine wear was determined
using the NMMA Yamaha CESOS Lubricity test. Oxidation induction time was
determined using a high pressure differential scanning calorimeter (HPDSC)
to having isothermal/isobaric conditions of 220°C and 500 psi (3.445
MPa) air,
respectively. Aquatic toxicity was determined using the Dispersion Aquatic
Toxicity test. The acid number was determined using ASTM # D-664. The
hydroxyl number of the respective samples was determined by infrared
spectroscopy.
Table 1
Pour Vis Vis. *Sol
@ @
Vis.
@
Point-25C 40C 100C with Engine
Base stock C (cPs) (cSt)(cSt) % Bio. Wear
Disp.
2o Natural Oils
Rapeseed Oil 0 Solid 47.8010.19 86.7 n/a n/a
All Linear Esters
Di-undecyladipate +21 solid 13.922.80 n/a n/a n/a
Polyol w/Linear
& Semi-I inear
Acids
TPE/C810/C7 n/a solid 29.985.90 n/a n/a n/a
acid
TPE/DiPE/n-C7 -45 1380 24.705.12 82.31 H Fail
TPE/C7 acid -62 915 24.0 4.9 83.7 H Fail
TMP/n-C7,8,10 -85 350 17.274.05 61.7** Fail
C
TMP/C7 acid -71 378 14.1 3.4 76.5 C Fail
3o Branched Adipates
di-tridecyladipate-62 n/a 26.935.33 65.99 C Fail
All Branched
TPE/Iso-C8 acid -46 n/a 61.608.2 13.33 C n/a
* denotes solubility with dispersant: H= haze; C= clear.
** denotes the biodegradation for this material includes 15.5 wt% dispersant
, CA 02208219 2005-03-02
~r
Na denotes information was not available.
TPE denotes technical grade pentaerythritol.
TMP denotes trimethylolpropane.
C810 denotes predominantly a mixture of n-octanoic and n-decanoic acids, and
s may include small amounts of n-C6 and n-Cti acids. A typical sample of
C810 acid may contain, e.g., 3-5% n-C6, 48-58% n-Cs, 36-42% n-C,o, and
0.5-1% n-Ctz. ,
n-C7,8,10 denotes a blend of linear acids with 7, 8 and 10 carbon atoms, e.g.,
37%
mole % n-C-r acid, 39 mole % C, acid, 21 mole % C,o acid and 3 mole
to C6 acid.
C7 denotes a C7 acid produced by cobalt catalyzed oxo reaction of hexene-1,
that
is 70% linear and 30% a-branched. The composition includes
approximately 70% n-heptanoic acid, 22% Z-methylhexanoic acid, 6.5% Z-
ethylpentanoic acid, 1 % 4-methylhexanoic acid, and 0.5% 3.3-
15 dimethylpentanoic acid.
The properties of the branched ester base stock according to the present
invention were compared against various corrventional biodegradable lubricant
base stocks and the results are set forth below in Table 2.
Table 2
pcapem~ TPElCk8/C810 Rapeseed Oil DTDA TMP1iC18
Pour Point (°C) ~5 0 -54 -20
Flash Point (°C) 274 162 221 Na
-25C Viscosity 3600 solid Na 358,000
(cps)
40C Viscosity (cSt) 38.78 47.$0 26.93 78.34
100C Viscosity (cSt)6.68 10.19 5.33 11.94
V150QSitV Index 128 208 135 147
Oxidation Induction 15.96 2.12 3.88 4.29
Timeo
Lnbricity (YarnahaTMPass Na Fail Pass
Engine)
BlodeOa (Mod. SNrm) -85% -$5% -~60% -b5%
Toxicity (LC50, ppm) >5000 >5000 <1000 Na
Solubility with DispersantsolubleNa solubleNa
Acid Number (mgKOH/g) 0.01 0.35 0.04 1.9
Hvdroxvl Number (meKOHle)1.91 Na 1.49 Na
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WO 96/17909 PCT/US95/16224
~.I
* Oxidation Induction Time is the amount of time (in minutes) for a molecule
to
oxidatively decompose under a particular set of conditions using a high
pressure
differential scanning calorimeter (I~DSC). The longer it takes (the greater
the number
of minutes), the more stable the molecule. This shows that the molecule of the
present
invention is almost four limes more oxidatively stable than any of the
materials currently
in use. The conditions used to evaluate these molecules were: 220°C and
500 psi (3.447
MPa) air.
denotes approximately.
> denotes greater than.
< denotes less than.
DTDA denotes di-tridecyladipate.
TMP/iCl8 denotes tri-ester of trimethylol propane and isostearic acid-
TPE denotes technical grade pentaervttuitol.
TMP denotes trimethylolpropane.
C810 denotes a mixture of 3-S% n-C6, 48-58% n-C8, 36-42% n-C10, and 0.5-1.0% n-
C12 acids.
Ck8 denotes Cekanoic-8 acid comprising a mixture of 26 wt.% 3,5-dimethyl
hexanoic acid, 19
wt.% 45-dimethyl hexanoic acid, 17% 3,4-dimethyl hexanoic acid. 11 wt.% 5-
methyl
heptanoic acid, 5 wt.% 4 methyl heptanoic acid, and 22 wt.% of mixed methyl-
heptanoic
acids and dimethvl hexanoic acids.
The data set forth in Table 2 above demonstrates that the TPE/C810/Ck8
biodegradable ester base stock according to the present invention is superior
to
rapeseed oil in cold flow properties and stability. The data also shows that
the
TPE/C810/Ck8 biodegradable ester base stock is superior to di-tridecyladipate
in
stability, biodegradation, and aquatic toxicity. The ester base stock
according to
the present invention is also superior to TMP/iso-C 18 in cold flow
properties,
stability, and biodegradation.
Rapeseed oil, a natural product, is very biodegradable, but it has very poor
low temperature properties and does not lubricate very well due to its
instability.
Rapeseed oil is very unstable and breaks down in the engine causing deposit
formation, sludge and corrosion problems. The di-undecyladipate, while
probably
biodegradable, also has very poor low temperature properties. Polyol esters of
low molecular weight linear acids do not provide lubricity, and those of high
molecular weight linear or semi-Linear acids have poor low temperature
properties.
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WO 96/17909 PCTIUS95/16224
In addition, the pentaerythritol esters of linear acids are not soluble with
polyamide
dispersants. The di-tridecyladipate is.only marginally biodegradable and, when
blended with a dispersant that has low biodegradability, the formulated oil is
only _
about 45% biodegradable. In addition, the di-ttidecyladipate does not provide
lubricity. Lower molecular weight branched adipates such as di-
isodecyladipate,
while more biodegradable, also do not provide lubricity and can cause seal
swell
problems. Polyol esters oftrimethylolpropane or pentaerythritol and branched
oxo
acids do not biodegrade easily due to the steric hindrance discussed earlier.
l0 EXAMPLE 2
The present inventors have discovered that highly biodegradable base
stocks with good cold flow properties, good solubility with dispersants, and
good
lubricity can be achieved by incorporating branched acids into the ester
molecule.
The data set forth in Table 3 below demonstrates that all of the desired base
stock
properties can be best met with polyol esters incorporating 20 to 70% of a
highly
branched oxo acid and 30 to 80% of a linear acid.
Table 3
Pour Vis @ Vis. @ Vis. @ * Sol
Point -25°C 40°C 100°C with Engine
B~ ~~k °C (cPs) (cSt) (cSt) % Bio Disp. Wear
TPE/C810/Ck8 -36** 7455**34.87 6.37 99.54 C Pass
TPE/C810/Ck8 and
TMP/n-C7,8,10*** -56 610 24.90 5.10 81.0 C Pass
TPE/C810/Ck8 and
TPE/1770**** -46 910 30.48 5.75 85.5 H Pass
* Denotes solubility with dispersant: H= haze: C= clear.
** Denotes Pour Point and -25°C Viscosity of Base stock with
Dispersant.
*** Denotes a 50:50 weight % ratio of TPE/C810/Ck8 and TMP/7810. ,
**** Denotes a 50:50 weight % ratio of TPElC810/Ck8 and TPE/1770.
1770 denotes a 70:30 mix of n-Co acid (70%) and alpha-branched C, acids (30%).
The
composition includes approximately 70% n-heptanoic acid. 22% 2-methylhexanoic
acid.
6.5% 2-ethylpentanaic acid, 1% .~-methylhexanoic acid. and 0.5% 3.3-
dimethylpentanoic acid.
TPE denotes technical grade pentaervthritol.
CA 02208219 1997-06-06
WO 96/17909 PCTIITS95/16224
'TMP denotes trimethyiolpropane.
C810 denotes a mixture of 3-5% n-C6, 48-58% n-C8. 36-42% n-C10, and 0.5-1.0% n-
C12
acids.
Ck8 denotes Cekanoic-8 acid comprising a mixture of 26 wt.% 3,5-dimethyl
hexanoic acid, 19
wt.% 4,5-dimethyl hexanoic acid. 17% 3,.t-dimethyl hexanoic acid, l lwt.% 5-
methyl
heptanoic acid 5 wt.% 4 methyl heptanoic acid. and 22 wt.% of mixed methyl
heptanoic
acids and dimethvl hexanoic acids.
n-C7,8,10 denotes a blend of linear acids with 7, 8 and 10 carbon atoms, e.g.,
37% mole % n-C,
acid, 39 mole % Ca acid, 21 mole % C,o acid and 3 mole % C6 acid.
The data in Table 3 above shows that the polyol ester of technical grade
pentaerythritol, iso-C8 and linear C810 acids can be used alone or in
combination
with other lower molecular weight esters as a biodegradable lubricant. These
esters are particularly useful when lower viscosities are needed for a variety
of
biodegradable lubricant applications. The TPE/C810/Ck8 ester provides
sufficient
lubricity such that, even when diluted with other materials, it can meet the
lubricity
requirements without the addition of wear additives. When additives such as
polyisobutylene, EP (extreme pressure) wear additives, corrosion inhibitors,
or
antioxidants are needed, the biodegradability of the final product can be
reduced
and the toxicity increased. If the base stock provides the needed properties
without additives or if the additives needed can be minimized, the final
product
reflects the biodegradability and toxicity of the base stock, which in this
case are
high and low, respectively.
EXAMPLE 3
A sample of an ester base stock was prepared in accordance with the
present invention wherein 220 lbs. (99.8 kg) of a C810 acid and 205 lbs. (93
kg) of
Cekanoic 8 acid (a 50:50 molar ratio) were loaded into a reactor vessel and
heated
to 430°F (221°C) at atmospheric pressure. Thereafter, 75 lbs.
(34 kg) oftechnical
3o grade pentaerythritol were added to the acid mixture and the pressure was
dropped
until water began evolving. The water was taken overhead to drive the
reaction.
After about 6 hours of reaction time, the excess acids were removed overhead
until
a total acid number of 0.26 mgKOH/g was reached for the reaction product. The
product was then neutralized and decolored for two hours at 90°C with
twice the
stoichiometric amount of Na2C03 (based on acid number) and 0.15 wt.% admix
CA 02208219 1997-06-06
WO 96/17909 PCT/US95116224
a~
(based on amount in the reactor). The admix is a blend of 80 wt.% carbon black
-
and 20 wt.% dicalite. After two hours at 90°C, the product was vacuum
filtered
to remove solids.
The properties set forth below in Table 4 were measured on the product:
Table 4
1o Total Acid Number 0.071 mgKOH/g
Specific Gravity 0.9679
Pour Point -45C
ppm Water 97
Flash Point (COC) 285C
Oxidation Induction Time15.96
(min.)
Viscosity @ -25C 3950 cps
Viscosity @ 40C 38.88 cSt
Viscosity @100C 6.66 cSt -
Viscosity Index 127
An acid assay (saponification) was performed on the product in order to
ascertain the amount of each acid actually on the molecule. Table 5 below sets
forth the molar amounts of each acid on the product ester:
Table ~
Cekanoic 8 Acid 43.35%
n-Cg Acid 3 5 .73
nC,o Acid 20.92%
This resultant ester product was then submitted with and without additives -
for biodegradation tests for application into the hydraulic fluid market. The
additives were used at a 2-5 wt.% treat rate. The results are set forth below
in
Table 6.
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WO 96/17909 PCT/US95/16224
- Table 6
Standard Meet 10 day
' Product % Biodeg. Deviation Window
TPE/C810/Ck8 (alone) 92.9 ~ 7.0 ves
TPE/C810/Ck8 + BIO SHP Adpack* 80.5 ~ 1.6 no
TPE/C810/Ck8 + MGG Adpack*** 75.4 t 6.9 no
TPE/C810/Ck8 + Svnestic Adpack** 76.8 ~14.7 no
* Denotes a lubricant additive package sold by Exxon Company, USA, under the
trademark Univis BIO SHP Adpack.
** Denotes a lubricant additive package sold by Exxon Chemical Company,
Paramins
Division under the trademark Svnestic Adpack.
*** Denotes a lubricant additive package sold by Exxon Company, USA under the
trademark MGG Adpack.
The resultant ester base stock formed in accordance with this Example 3
was also blended at a 50:50 wt.% ratio with the ester TMP/7810. This blend was
submitted with and without additives for biodegradation tests for application
into
the two-cycle engine oil market. The additives were used at a 14-16 wt.%-treat
rate. The results are set forth in Table 7 below.
Table 7
Standard
Product % Biodeg. Deviation
TPFJC810/Ck8 + TMP/7810 (50:50) 80.7 t3.6
TPE/C810/Ck8 + TMP/7810 + 14.5 wt.% Dispersant* 76.1 ~4.6
* The dispersant package comprising primarily of polyamides.
EXAMPLE 4
~ Table 8 below contains comparative data for all-linear and semi-linear
3o esters verses the biodegradable synthetic ester base stock formed according
to the
- present invention. We have provided two examples of the ester base stock
according to the present invention because they contain two different molar
ratios
of Cekanoic 8 to C810. The results indicate that a certain amount of branching
does not greatly affect biodegradation as measured by the Modified Sturm test
and
may, in fact. actually improve it which is contrary to conventional wisdom.
CA 02208219 1997-06-06
WO 96117909 pCT~TS95/16224
Table 8 -
Biodegradation Standard 10-Day
Ester (28 Days) Deviation Window
Totally Linear Ester
TMP/7810 76.13 8.77 no
TPEIDi-PE/n-C7 82.31 6.25 yes
L9 Adipate 89.63 6.28 yes
MPD/AA/C810 86.09 3.76 yes
Semi-Linear Ester
l0 TMP/isostearate 63.32 1.91 no
TMP/1770 76.46 1.58 no
TMP/1770 83.65 6.89 no
Branched Ester
TPE/C810/Ck8* 92.90 ~ 7.00 yes
TPE/C810/Ck8** 99.54 1.85 yes
Notes: TNiP/7810 denotes a tri-ester of trimetholpropane and C7, Cs and C,o
acids.
TPEIDi-PE/n-C~ denotes esters of technical grade pentaerythritol, di-
pentaerythritiol and n-C, acid.
2o L9 Adipate denotes a di-ester of adipic acid and n-C9 alcohol.
MPD/AA/C810 denotes a complex ester of 2-methyl-1-,3-propanediol (2
mols), adipic acid (1 mol) and n-Cs and C,o acids (2 mol).
Rapeseed Oil is a tri-ester of glycerol and stearic acid.
TMPlisostearate denotes a tri-ester of trimethylolpropane and iso-stearic
acid ( 1 methyl branch per acid chain).
TMP/1770 denotes a tri-ester of trimethylolpropane and a 70:30 mix of n-
C7 acid (70%) and alpha-branched C, acids (30%). The 1770
composition includes approximately 70% n-heptanoic acid, 22% 2-
methylhexanoic .acid, 6.5% 2-ethylpentanoic acid, 1% 4-
3o methylhexanoic acid, and 0.5% 3.3-dimethylpentanoic acid.
TPE/1770 denotes esters of technical grade pentaerythritol and a 70:30 mix ,
of n-C7 acid (70%) and alpha-branched C~ acids (30%). The 1770
composition includes approximately 70% n-heptanoic acid, 22% 2-
methylhexanoic acid, 6.5% 2-ethylpentanoic acid, 1% 4-
methylhexanoic acid, and 0.5% 3.3-dimethylpentanoic acid.
CA 02208219 1997-06-06
WO 96/17909 - PCT/US95/16224
a"l
- * TPE/C810/Ck8 denotes esters of technical grade pentaerythritol and a
45:55 molar ratio of iso-Cs acid (Ck8) and C810 acid.
" ** TPE/C810/Ck8 denotes esters of technical grade gentaerythritol and a
30:70 molar ratio of iso-Cg acid (Ck8) and C810 acid.
10
20
30
,.t = ,~
5
~~s~ E (VI ~ ~ t' .
~~ ~ , n
