Note: Descriptions are shown in the official language in which they were submitted.
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TITLE
LUBRICATION OIL COMPOSITIONS
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to commonly owned U.S. Application Serial No.
11/593,954, filed November 7, 2006, entitled "POLYTRIMETHYLENE ETHER GLY-
COL ESTERS"; commonly owned U.S. Provisional Application Serial No.
60/957,716,
filed concurrently herewith, entitled "LUBRICATION OIL COMPOSITIONS"; commonly
owned U.S. Provisional Application Serial No. 60/957,725, filed concurrently
herewith,
entitled "LUBRICATION OIL COMPOSITIONS" (Internal Reference CL3886); and com-
monly owned U.S. Provisional Application Serial No. 60/957,722, filed
concurrently
herewith, entitled "LUBRICATION OIL COMPOSITIONS" (Internal Reference CL3887).
FIELD OF THE INVENTION
This invention relates compositions comprising (i) a poly(trimethylene-
ethylene
ether) glycol and (ii) an additive package comprising certain specified
additive combi-
nations, and lubrication oils containing the compositions.
BACKGROUND
Certain polytrimethylene ether glycols ("PO3Gs"), including but not limited to
poly(trimethylene-ethylene ether) glycols, and mono- and diesters thereof
("PO3G es-
ters"), have properties that make them useful in a variety of fields,
including as lubri-
cants, as disclosed in commonly owned US7179769 and U.S. Application Serial
No.
11/593,954, filed November 7, 2006, entitled "POLYTRIMETHYLENE ETHER GLY-
COL ESTERS".
Because of these properties, it is desirable to formulate lubricant
compositions
based on PO3Gs and PO3G esters.
SUMMARY OF THE INVENTION
The present invention is directed to compositions based on combinations of a
specific type of PO3G (a poly(trimethylene-ethylene ether) glycol - PTEEG)
with spe-
cific additive combinations, which compositions have properties making them
espe-
cially suited for lubrication end uses.
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In one embodiment, there is provided a lubrication oil composition comprising
(i) a base fluid stock comprising a PTEEG that is fluid at ambient
temperature, and (ii)
an additive package comprising:
(a) an antiwear additive package comprising from about 0.5 to about 2.0
wt% (based on total composition weight) of a mixture comprising an amine
phosphate
antiwear additive and a phosphorothionate antiwear additive, and
(b) from about 0.1 to about 0.5 wt.% (based on total composition weight) of
an additive that functions as an extreme pressure additive, as an antioxidant
additive,
or as an extreme pressure additive and an antioxidant additive. In preferred
embodiments the additive that functions as an extreme pressure additive, as an
antioxidant additive, or as an extreme pressure additive and an antioxidant
additive. Is
a methylene bis(dialkyldithiocarbamate)
When the PTEEG is based on biologically produced 1,3-propanediol, lubricant
compositions with a very high renewable content can be provided.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Unless otherwise defined, all technical and scientific terms used herein have
the same meaning as commonly understood by one of ordinary skill in the art to
which
this invention belongs. In case of conflict, the present specification,
including defini-
tions, will control.
Except where expressly noted, trademarks are shown in upper case.
Unless stated otherwise, all percentages, parts, ratios, etc., are by weight.
When an amount, concentration, or other value or parameter is given as either
a range, preferred range or a list of upper preferable values and lower
preferable val-
ues, this is to be understood as specifically disclosing all ranges formed
from any pair
of any upper range limit or preferred value and any lower range limit or
preferred value,
regardless of whether ranges are separately disclosed. Where a range of
numerical
values is recited herein, unless otherwise stated, the range is intended to
include the
endpoints thereof, and all integers and fractions within the range. It is not
intended that
the scope of the invention be limited to the specific values recited when
defining a
range.
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When the term "about" is used in describing a value or an end-point of a
range,
the disclosure should be understood to include the specific value or end-point
referred
to.
As used herein, the terms "comprises," "comprising," "includes," "including,"
"has," "having" or any other variation thereof, are intended to cover a non-
exclusive
inclusion. For example, a process, method, article, or apparatus that
comprises a list
of elements is not necessarily limited to only those elements but may include
other
elements not expressly listed or inherent to such process, method, article, or
appara-
tus. Further, unless expressly stated to the contrary, "or" refers to an
inclusive or and
not to an exclusive or. For example, a condition A or B is satisfied by any
one of the
following: A is true (or present) and B is false (or not present), A is false
(or not pre-
sent) and B is true (or present), and both A and B are true (or present).
Use of "a" or "an" are employed to describe elements and components of the
invention. This is done merely for convenience and to give a general sense of
the in-
vention. This description should be read to include one or at least one and
the singular
also includes the plural unless it is obvious that it is meant otherwise.
The materials, methods, and examples herein are illustrative only and, except
as specifically stated, are not intended to be limiting. Although methods and
materials
similar or equivalent to those described herein can be used in the practice or
testing of
the present invention, suitable methods and materials are described herein.
Base Fluid Stock
As indicated above, the base fluid stock for use in the lubrication oil
composi-
tions of the present invention comprises a PTEEG that is a fluid at ambient
tempera-
ture (25 C). The base fluid stock may also comprise other natural and/or
synthetic
fluid co-lubricants.
Examples of natural fluid co-lubricants include vegetable oil-based
lubricants,
which are generally derived from plants and are generally composed of
triglycerides.
Normally, these are liquid at room temperature. Although many different parts
of
plants may yield oil, in actual practice oil is generally extracted primarily
from the seeds
of oilseed plants. These oils include both edible and inedible oils, and
include, for ex-
ample, high oleic sunflower oil, rapeseed oil, soybean oil, castor oil and the
like, as well
as modified oils such as disclosed in US6583302 (fatty acid esters) and I.
Malchev,
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"Plant-Oil-Based Lubricants" (available from the Department of Plant
Agriculture, On-
tario Agriculture College, University of Guelph, 50 Stone Road W., Guelph,
Ontario,
Canada N1G 2W1).
Synthetic fluid co-lubricants (other than the PO3G and PO3G esters) include
lubricating oils such as hydrocarbon oils such as polybutylenes,
polypropylenes, pro-
pylene-isobutylene copolymers; polyoxyalkylene glycol polymers (other than
PO3G)
and their derivatives such as ethylene oxide and propylene oxide copolymers;
and es-
ters of dicarboxylic acids with a variety of alcohols such as dibutyl adipate,
di(2-
ethylhexyl) sebacate , di-hexyl fumarate, dioctyl sebacate, diisoctyl azelate,
diisodecyl
azelate, dioctyl phthalate, didecyl phthalate, and the 2-ethylhexyl diester of
linoleic acid
dimer.
PO3Gs other than PTEEGs, as well as PO3G esters generally (including but
not limited to esters of PTEEGs), can be used as synthetic fluid co-lubricants
as well.
Preferably, the base stock comprises a predominant amount of PTEEG (greater
than 50 wt% based on the weight of the base stock). In some embodiments, the
base
stock can comprise the PTEEG in an amount of about 66 wt% or greater, or about
75
wt% or greater, or about 90 wt% or greater, or about 95 wt% or greater, based
on the
total weight of the base fluid stock. In some preferred embodiments, the base
fluid
stock comprises only (or substantially only) the PTEEG.
A portion of the PTEEG can be replaced with a PTEEG ester, and the amounts
referred to above can be for the combination of PTEEG plus PTEEG ester. In one
embodiment, the weight ratio of PTEEG/PTEEG ester in the base fluid stock is
1:1 or
greater, or greater than 1:1 (the PTEEG being the predominant component), or
about
1.5:1 or greater, or about 2:1 or greater, or about 5:1 or greater, or about
20:1 or
greater. Also, the weight ratio is preferably about 25:1 or less, or about
20:1 or less, or
about 10:1 or less.
The lubrication oil composition preferably comprises the base oil stock in an
amount of about 50 wt% or greater, based on the total weight of the
lubrication oil
composition. In various embodiments, the lubrication oil can comprise the base
stock
in an amount of about 75 wt% or greater, or about 90 wt% or greater, or about
95 wt%
or greater, based on the total weight of the lubrication oil composition.
Polytrimethylene Ether Glycol (PO3G) Generally
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PO3G for the purposes of the present invention (including PTEEG) is an oli-
gomeric or polymeric ether glycol in which at least 50% of the repeating units
are
trimethylene ether units.
PO3G is preferably prepared by polycondensation of monomers comprising
1,3-propanediol, preferably in the presence of an acid catalyst, thus
resulting in poly-
mers or copolymers containing -(CH2CH2CH2O)- linkage (e.g, trimethylene ether
re-
peating units). As indicated above, at least 50% of the repeating units are
trimethylene
ether units.
When a sulfur-based acid catalyst is utilized (such as sulfuric acid) to
prepare
the PO3G, the resulting product preferably contains less than about 20 ppm,
more
preferably less than about 10 ppm, of sulfur.
In addition to the trimethylene ether units, lesser amounts of other units,
such
as other polyalkylene ether repeating units, may be present. In the context of
this dis-
closure, the term "polytrimethylene ether glycol" encompasses PO3G made from
es-
sentially pure 1,3-propanediol, as well as those oligomers and polymers
(including
PTEEG and others described below) containing up to about 50% by weight of co-
monomers.
For PTEEG, the other polyalkylene ether repeating units are predominantly
ethylene ether units.
The 1,3-propanediol employed for preparing the PO3G may be obtained by any
of the various well known chemical routes or by biochemical transformation
routes.
Preferred routes are described in, for example, US5015789, US5276201,
US5284979,
US5334778, US5364984, US5364987, US5633362, US5686276, US5821092,
US5962745, US6140543, US6232511, US6235948, US6277289, US6297408,
US6331264, US6342646, US7038092, US7084311, US7098368, US7009082 and
US20050069997A1. Preferably, the 1,3-propanediol is obtained biochemically
from a
renewable source ("biologically-derived" 1,3-propanediol).
A particularly preferred source of 1,3-propanediol is via a fermentation
process
using a renewable biological source. As an illustrative example of a starting
material
from a renewable source, biochemical routes to 1,3-propanediol (PDO) have been
de-
scribed that utilize feedstocks produced from biological and renewable
resources such
as corn feed stock. For example, bacterial strains able to convert glycerol
into 1,3-
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propanediol are found in the species Klebsiella, Citrobacter, Clostridium, and
Lactoba-
cillus. The technique is disclosed in several publications, including
US5633362,
US5686276 and US5821092. US5821092 discloses, inter alia, a process for the
bio-
logical production of 1,3-propanediol from glycerol using recombinant
organisms. The
process incorporates E. coli bacteria, transformed with a heterologous pdu
diol dehy-
dratase gene, having specificity for 1,2-propanediol. The transformed E. coli
is grown
in the presence of glycerol as a carbon source and 1,3-propanediol is isolated
from the
growth media. Since both bacteria and yeasts can convert glucose (e.g., corn
sugar)
or other carbohydrates to glycerol, the processes disclosed in these
publications pro-
vide a rapid, inexpensive and environmentally responsible source of 1,3-
propanediol
monomer.
The biologically-derived 1,3-propanediol, such as produced by the processes
described and referenced above, contains carbon from the atmospheric carbon
dioxide
incorporated by plants, which compose the feedstock for the production of the
1,3-
propanediol. In this way, the biologically-derived 1,3-propanediol preferred
for use in
the context of the present invention contains only renewable carbon, and not
fossil
fuel-based or petroleum-based carbon. The PO3Gs based thereon utilizing the
bio-
logically-derived 1,3-propanediol, therefore, have less impact on the
environment as
the 1,3-propanediol used in the compositions does not deplete diminishing
fossil fuels
and, upon degradation, releases carbon back to the atmosphere for use by
plants once
again. Thus, the compositions of the present invention can be characterized as
more
natural and having less environmental impact than similar compositions
comprising
petroleum based glycols.
The biologically-derived 1,3-propanediol, PO3G and PO3G esters, may be dis-
tinguished from similar compounds produced from a petrochemical source or from
fos-
sil fuel carbon by dual carbon-isotopic finger printing. This method usefully
distin-
guishes chemically-identical materials, and apportions carbon in the copolymer
by
source (and possibly year) of growth of the biospheric (plant) component. The
iso-
topes, 14 C and13C, bring complementary information to this problem. The
radiocarbon
dating isotope (14C), with its nuclear half life of 5730 years, clearly allows
one to appor-
tion specimen carbon between fossil ("dead") and biospheric ("alive")
feedstocks (Cur-
rie, L. A. "Source Apportionment of Atmospheric Particles," Characterization
of Envi-
ronmental Particles, J. Buffle and H.P. van Leeuwen, Eds., 1 of Vol. I of the
IUPAC
Environmental Analytical Chemistry Series (Lewis Publishers, Inc) (1992) 3-
74). The
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basic assumption in radiocarbon dating is that the constancy of 14C
concentration in
the atmosphere leads to the constancy of 14C in living organisms. When dealing
with
an isolated sample, the age of a sample can be deduced approximately by the
rela-
tionship:
t = (-5730/0.693)In(A/Ao)
wherein t = age, 5730 years is the half-life of radiocarbon, and A and Ao are
the spe-
cific14C activity of the sample and of the modern standard, respectively
(Hsieh, Y., Soil
Sci. Soc. Am J., 56, 460, (1992)). However, because of atmospheric nuclear
testing
since 1950 and the burning of fossil fuel since 1850, 14C has acquired a
second, geo-
chemical time characteristic. Its concentration in atmospheric C02, and hence
in the
living biosphere, approximately doubled at the peak of nuclear testing, in the
mid-
1960s. It has since been gradually returning to the steady-state cosmogenic
(atmos-
pheric) baseline isotope rate (14C/12C) of ca. 1.2 x 10-12, with an
approximate relaxation
"half-life" of 7-10 years. (This latter half-life must not be taken literally;
rather, one must
use the detailed atmospheric nuclear input/decay function to trace the
variation of at-
mospheric and biospheric 14C since the onset of the nuclear age.) It is this
latter bio-
spheric 14C time characteristic that holds out the promise of annual dating of
recent
biospheric carbon. 14C can be measured by accelerator mass spectrometry (AMS),
with results given in units of "fraction of modern carbon" (fM). fM is defined
by National
Institute of Standards and Technology (NIST) Standard Reference Materials
(SRMs)
4990B and 4990C, known as oxalic acids standards HOxI and HOxII, respectively.
The fundamental definition relates to 0.95 times the 14C/12C isotope ratio
HOxI (refer-
enced to AD 1950). This is roughly equivalent to decay-corrected pre-
Industrial Revo-
lution wood. For the current living biosphere (plant material), fM =1.1.
The stable carbon isotope ratio (13C/12C) provides a complementary route to
source discrimination and apportionment. The13C/12C ratio in a given
biosourced ma-
terial is a consequence of the13C/12C ratio in atmospheric carbon dioxide at
the time
the carbon dioxide is fixed and also reflects the precise metabolic pathway.
Regional
variations also occur. Petroleum, C3 plants (the broadleaf), C4 plants (the
grasses),
and marine carbonates all show significant differences in13C/12C and the
correspond-
ing b13C values. Furthermore, lipid matter of C3 and C4 plants analyze
differently than
materials derived from the carbohydrate components of the same plants as a
conse-
quence of the metabolic pathway. Within the precision of measurement, 13C
shows
large variations due to isotopic fractionation effects, the most significant
of which for
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the instant invention is the photosynthetic mechanism. The major cause of
differences
in the carbon isotope ratio in plants is closely associated with differences
in the path-
way of photosynthetic carbon metabolism in the plants, particularly the
reaction occur-
ring during the primary carboxylation, i.e., the initial fixation of
atmospheric CO2. Two
large classes of vegetation are those that incorporate the "C3" (or Calvin-
Benson) pho-
tosynthetic cycle and those that incorporate the "C4" (or Hatch-Slack)
photosynthetic
cycle. C3 plants, such as hardwoods and conifers, are dominant in the
temperate cli-
mate zones. In C3 plants, the primary CO2 fixation or carboxylation reaction
involves
the enzyme ribulose-1,5-diphosphate carboxylase and the first stable product
is a
3-carbon compound. C4 plants, on the other hand, include such plants as
tropical
grasses, corn and sugar cane. In C4 plants, an additional carboxylation
reaction involv-
ing another enzyme, phosphenol-pyruvate carboxylase, is the primary
carboxylation
reaction. The first stable carbon compound is a 4-carbon acid, which is
subsequently
decarboxylated. The CO2 thus released is refixed by the C3 cycle.
Both C4 and C3 plants exhibit a range of 13C/12C isotopic ratios, but typical
val-
ues are ca. -10 to -14 per mil (C4) and -21 to -26 per mil (C3) (Weber et al.,
J. Agric.
Food Chem., 45, 2942 (1997)). Coal and petroleum fall generally in this latter
range.
The 13C measurement scale was originally defined by a zero set by pee dee
belemnite
(PDB) limestone, where values are given in parts per thousand deviations from
this
material. The "()13C" values are in parts per thousand (per mil), abbreviated
%, and are
calculated as follows:
b13C (13C/12C sample -(13C/12C)standard x 1000%
(13C/12C)standard
Since the PDB reference material (RM) has been exhausted, a series of
alternative
RMs have been developed in cooperation with the IAEA, USGS, NIST, and other se-
lected international isotope laboratories. Notations for the per mil
deviations from PDB
is b13C. Measurements are made on CO2 by high precision stable ratio mass spec-
trometry (IRMS) on molecular ions of masses 44, 45 and 46.
Biologically-derived 1,3-propanediol, and compositions comprising biologically-
derived 1,3-propanediol, therefore, may be completely distinguished from their
petro-
chemical derived counterparts on the basis of 14C (fM) and dual carbon-
isotopic finger-
printing, indicating new compositions of matter. The ability to distinguish
these prod-
ucts is beneficial in tracking these materials in commerce. For example,
products
comprising both "new" and "old" carbon isotope profiles may be distinguished
from
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products made only of "old" materials. Hence, the instant materials may be
followed in
commerce on the basis of their unique profile and for the purposes of defining
competi-
tion, for determining shelf life, and especially for assessing environmental
impact.
Preferably the 1,3-propanediol used as the reactant or as a component of the
reactant will have a purity of greater than about 99%, and more preferably
greater than
about 99.9%, by weight as determined by gas chromatographic analysis.
Particularly
preferred are the purified 1,3-propanediols as disclosed in US7038092,
US7098368,
US7084311 and US20050069997A1, as well as PO3G made therefrom as disclosed
in US20050020805A1.
The purified 1,3-propanediol preferably has the following characteristics:
(1) an ultraviolet absorption at 220 nm of less than about 0.200, and at 250
nm
of less than about 0.075, and at 275 nm of less than about 0.075; and/or
(2) a composition having L*a*b* "b*" color value of less than about 0.15 (ASTM
D6290), and an absorbance at 270 nm of less than about 0.075; and/or
(3) a peroxide composition of less than about 10 ppm; and/or
(4) a concentration of total organic impurities (organic compounds other than
1,3-propanediol) of less than about 400 ppm, more preferably less than about
300
ppm, and still more preferably less than about 150 ppm, as measured by gas
chroma-
tography.
The starting material for making PO3G will depend on the desired PO3G, avail-
ability of starting materials, catalysts, equipment, etc., and comprises "1,3-
propanediol
reactant." By "1,3-propanediol reactant" is meant 1,3-propanediol, and
oligomers and
prepolymers of 1,3-propanediol preferably having a degree of polymerization of
2 to 9,
and mixtures thereof. In some instances, it may be desirable to use up to 10%
or more
of low molecular weight oligomers where they are available. Thus, preferably
the start-
ing material comprises 1,3-propanediol and the dimer and trimer thereof. A
particularly
preferred starting material is comprised of about 90% by weight or more 1,3-
propanediol, and more preferably 99% by weight or more 1,3-propanediol, based
on
the weight of the 1,3-propanediol reactant.
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PO3G can be made via a number of processes known in the art, such as dis-
closed in US6977291 and US6720459. The preferred processes are as set forth in
US7074969, US7157607, US7161045 and US7164046.
As indicated above, PO3G may contain lesser amounts of other polyalkylene
ether repeating units in addition to the trimethylene ether units. The
monomers for use
in preparing PO3G can, therefore, contain up to 50% by weight of comonomer
polyols
in addition to the 1,3-propanediol reactant. Comonomer polyols that are
suitable for
use in the process include aliphatic diols, for example, ethylene glycol, 1,6-
hexanediol,
1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-
dodecanediol,
3,3,4,4,5,5-hexafluro-1,5-pentanediol, 2,2,3,3,4,4,5,5-octafluoro-1,6-
hexanediol, and
3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10-hexadecafluoro-1,12-dodecanediol;
cycloaliphatic di-
ols, for example, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and
isosorbide; and
polyhydroxy compounds, for example, glycerol, trimethylolpropane, and
pentaerythritol.
A preferred group of comonomer diols is selected from the group consisting of
ethylene
glycol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-
1,3-
propanediol, 2-ethyl-2-(hydroxymethyl)-1,3-propanediol, C6 - C,o diols (such
as
1,6-hexanediol, 1,8-octanediol and 1,10-decanediol) and isosorbide, and
mixtures
thereof. A particularly preferred diol other than 1,3-propanediol is ethylene
glycol, and
C6 - C,o diols can be particularly useful as well.
Suitable PTEEGs for use in the present invention are described, for example,
in
US20040030095A1. Preferred PTEEGs are prepared by acid catalyzed polyconden-
sation of from 50 to about 99 mole% (preferably from about 60 to about 98
mole%, and
more preferably from about 70 to about 98 mole%) 1,3-propanediol and up to 50
to
about 1 mole% (preferably from about 40 to about 2 mole%, and more preferably
from
about 30 to about 2 mole%) ethylene glycol.
Preferably, the PTEEG after purification has essentially no acid catalyst end
groups, but may contain very low levels of unsaturated end groups,
predominately allyl
end groups, in the range of from about 0.003 to about 0.03 meq/g. Such a PTEEG
can be considered to comprise (consist essentially of) the compounds having
the fol-
lowing formulae (I) and (II):
HO-((CH2)30)m((CH2)20)n-H (I)
HO-((CH2)3-O)m((CH2)20)nCH2CH=CH2 (II)
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wherein m and n are in a range such that the Mn (number average molecular
weight) is
within the range of from about 200 to about 10000, with compounds of formula
(III) be-
ing present in an amount such that the allyl end groups (preferably all
unsaturation
ends or end groups) are present in the range of from about 0.003 to about 0.03
meq/g.
The PTEEGs can be random or block copolymers, and formulas (I) and (II) are
intended to cover both varieties.
The preferred PO3G (including PTEEG) for use in the invention has an Mn
(number average molecular weight) of at least about 250, more preferably at
least
about 1000, and still more preferably at least about 2000. The Mn is
preferably less
than about 10000, more preferably less than about 5000, and still more
preferably less
than about 3500. Blends of PO3Gs can also be used. For example, the PO3G can
comprise a blend of a higher and a lower molecular weight PO3G, preferably
wherein
the higher molecular weight PO3G has a number average molecular weight of from
about 1000 to about 5000, and the lower molecular weight PO3G has a number
aver-
age molecular weight of from about 200 to about 950. The Mn of the blended
PO3G
will preferably still be in the ranges mentioned above.
PO3G preferred for use herein is typically polydisperse having a
polydispersity
(i.e. Mw/Mn) of preferably from about 1.0 to about 2.2, more preferably from
about 1.2
to about 2.2, and still more preferably from about 1.5 to about 2.1. The
polydispersity
can be adjusted by using blends of P03G.
PO3G for use in the present invention preferably has a color value of less
than
about 100 APHA, and more preferably less than about 50 APHA, and a viscosity
which
is preferably about 100cS or greater at 40 C.
PO3G Esters
In some embodiments, the PO3G esters comprise one or more compounds of
the formula (III):
O
R O Q O R III
II
~ 2 ()
wherein Q represents the residue of a PO3G after abstraction of the hydroxyl
groups,
R2 is H or R3CO, and each of R, and R3 is individually a substituted or
unsubstituted
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aromatic, saturated aliphatic, unsaturated aliphatic or cycloaliphatic organic
group,
containing from 4 to 40 carbon atoms, preferably at least 6 carbon atoms, more
pref-
erably at least 8 carbon atoms. In some embodiments each of R, and R3 has 20
car-
bon atoms or fewer, and in some embodiments 10 carbon atoms or fewer. In some
preferred embodiments, each of R, and R3 has 8 carbon atoms.
PO3G esters are preferably prepared by polycondensation of hydroxyl groups-
containing monomers (monomers containing 2 or more hydroxyl groups)
predominantly
comprising 1,3-propanediol to form a PO3G (as disclosed above), followed by
esterifi-
cation with a monocarboxylic acid (or equivalent), as disclosed in U.S.
Application Se-
rial No. 11/593,954, filed November 7, 2006, entitled "POLYTRIMETHYLENE ETHER
GLYCOL ESTERS".
The PO3G ester thus prepared is a composition preferably comprising from
about 50 to 100 wt%, more preferably from about 75 to 100 wt%, diester and
from 0 to
about 50 wt%, more preferably from 0 to about 25 wt%, monoester, based on the
total
weight of the esters. Preferably the mono- and diesters are esters of 2-
ethylhexanoic
acid.
The PO3G used for preparing the ester need not be the same as the PO3G co-
component of the base fluid stock.
Acid and Eguivalents
The esterification of the PO3G is carried out by reaction with an acid and/or
equivalent, preferably a monocarboxylic acid and/or equivalent.
By "monocarboxylic acid equivalent" is meant compounds that perform sub-
stantially like monocarboxylic acids in reaction with polymeric glycols and
diols, as
would be generally recognized by a person of ordinary skill in the relevant
art. Mono-
carboxylic acid equivalents for the purpose of the present invention include,
for exam-
ple, esters of monocarboxylic acids, and ester-forming derivatives such as
acid halides
(e.g., acid chlorides) and anhydrides.
Preferably, a monocarboxylic acid is used having the formula R-COOH,
wherein R is a substituted or unsubstituted aromatic, aliphatic or
cycloaliphatic organic
moiety containing from 6 to 40 carbon atoms.
Mixtures of different monocarboxylic acids and/or equivalents are also
suitable.
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As indicated above, the monocarboxylic acid (or equivalent) can be aromatic,
aliphatic or cycloaliphatic. In this regard, "aromatic" monocarboxylic acids
are mono-
carboxylic acids in which a carboxyl group is attached to a carbon atom in a
benzene
ring system such as those mentioned below. "Aliphatic" monocarboxylic acids
are
monocarboxylic acids in which a carboxyl group is attached to a fully
saturated carbon
atom or to a carbon atom which is part of an olefinic double bond. If the
carbon atom
is in a ring, the equivalent is "cycloaliphatic."
The monocarboxylic acid (or equivalent) can contain any substituent groups or
combinations thereof (such as functional groups like amide, amine, carbonyl,
halide,
hydroxyl, etc.), so long as the substituent groups do not interfere with the
esterification
reaction or adversely affect the properties of the resulting ester product.
The monocarboxylic acids and equivalents can be from any source, but pref-
erably are derived from natural sources or are bio-derived.
The following acids and their derivatives are specifically preferred: lauric,
myris-
tic, palmitic, stearic, arachidic, benzoic, caprylic, erucic, palmitoleic,
pentadecanoic,
heptadecanoic, nonadecanoic, linoleic, arachidonic, oleic, valeric, caproic,
capric and
2-ethylhexanoic acids, and mixtures thereof. Particularly preferred acids or
derivatives
thereof are 2-ethylhexanoic acid, benzoic acid, stearic acid, lauric acid and
oleic acid.
Esterification Process
For preparation of the esters, the PO3G can be contacted, preferably in the
presence of an inert gas, with the monocarboxylic acid(s) at temperatures
ranging from
about 100 C to about 275 C, preferably from about 125 C to about 250 C. The
proc-
ess can be carried out at atmospheric pressure or under vacuum. During the
contact-
ing water is formed is formed and can be removed in the inert gas stream or
under
vacuum to drive the reaction to completion.
To facilitate the reaction of PO3G with carboxylic acid an esterfication
catalyst
is generally used, preferably a mineral acid catalyst. Examples of mineral
acid cata-
lysts include but are not restricted to sulfuric acid, hydrochloric acid,
phosphoric acid,
hydriodic acid, and heterogeneous catalysts such as zeolites, heteropolyacid,
amber-
lyst, and ion exchange resin. Preferred esterification acid catalysts are
selected from
the group consisting of sulfuric acid, phosphoric acid, hydrochloric acid and
hydroiodic
acid. A particularly preferred mineral acid catalyst is sulfuric acid.
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The amount of catalyst used can be from about 0.01 wt% to about 10 wt% of
the reaction mixture, preferably from 0.1 wt% to about 5 wt%, and more
preferably
from about 0.2 wt% to about 2 wt%, of the reaction mixture.
Any ratio of carboxylic acid, or derivatives thereof, to glycol hydroxyl
groups can
be used. The preferred ratio of acid to hydroxyl groups is from about 3:1 to
about 1:2,
where the ratio can be adjusted to shift the ratio of monoester to diester in
the product.
Generally to favor production of diesters slightly more than a 1:1 ratio is
used. To favor
production of monoesters, a 0.5:1 ratio or less of acid to hydroxyl is used.
A preferred method for esterification comprises polycondensing 1,3-propanediol
reactant to PO3G using a mineral acid catalyst, then adding carboxylic acid
and carry-
ing out the esterification without isolating and purifying the P03G. In this
method, the
etherification or polycondensation of 1,3-propanediol reactant to form PO3G is
carried
out using an acid catalyst as disclosed in US6977291 and US6720459. The
etherifica-
tion reaction may also be carried out using a polycondensation catalyst that
contains
both an acid and a base as described in JP2004-182974A. The polycondensation
or
etherification reaction is continued until desired molecular weight is
reached, and then
the calculated amount of monocarboxylic acid is added to the reaction mixture.
The
reaction is continued while the water byproduct is removed. At this stage both
esterifi-
cation and etherification reactions occur simultaneously. Thus, in this
preferred esteri-
fication method the acid catalyst used for polycondensation of diol is also
used for es-
terification. If necessary additional esterification catalyst can be added at
the esterifi-
cation stage.
In this procedure, the viscosity (molecular weight) of the resulting product
is
controlled by the point at which the carboxylic acid is added.
In an alternative procedure, the esterification reaction can be carried out on
pu-
rified PO3G by addition of an esterification catalyst and carboxylic acid
followed by
heating and removal of water. In this procedure, viscosity of the resulting
product is
predominantly a function of the molecular weight of the PO3G utilized.
Regardless of which esterification procedure is followed, after the
esterification
step any by products are removed, and then the catalyst residues remaining
from poly-
condensation and/or esterification are removed in order to obtain an ester
product that
is stable, particularly at high temperatures. This may be accomplished by
hydrolysis of
the crude ester product by treatment with water at about 80 C to about 100 C
for a
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time sufficient to hydrolyze any residual acid esters derived from the
catalyst without
impacting significantly the carboxylic acid esters. The time required can vary
from
about 1 to about 8 hours. If the hydrolysis is carried out under pressure,
higher tem-
peratures and correspondingly shorter times are possible. At this point the
product
may contain diesters, monoesters, or a combination of diesters and monoesters,
and
small amounts of acid catalyst, unreacted carboxylic acid and diol depending
on the
reaction conditions. The hydrolyzed polymer is further purified to remove
water, acid
catalyst and unreacted carboxylic acid by the known conventional techniques
such as
water washings, base neutralization, filtration and/or distillation. Unreacted
diol and
acid catalyst can, for example, be removed by washing with deionized water.
Unre-
acted carboxylic acid also can be removed, for example, by washing with
deionized
water or aqueous base solutions, or by vacuum stripping.
Hydrolysis is generally followed by one or more water washing steps to remove
acid catalyst, and drying, preferably under vacuum, to obtain the ester
product. The
water washing also serves to remove unreacted diol. Any unreacted
monocarboxylic
acid present may also be removed in the water washing, but may also be removed
by
washing with aqueous base or by vacuum stripping.
If desired, the product can be fractionated further to isolate low molecular
weight esters by a fractional distillation under reduced pressure.
Proton NMR and wavelength X-ray fluorescence spectroscopic methods can be
used to identify and quantify any residual catalyst (such as sulfur) present
in the poly-
mer. The proton NMR can, for example, identify the sulfate ester groups
present in the
polymer chain, and wavelength x-ray fluorescence method can determine the
total sul-
fur (inorganic and organic sulfur) present in the polymer. The esters of the
invention
made from the process described above are substantially sulfur free and thus
useful
for high temperature applications.
Preferably, the PO3G esters after purification have essentially no acid
catalyst
end groups, but may contain very low levels of unsaturated end groups,
predominately
allyl end groups, in the range of from about 0.003 to about 0.03 meq/g. Such
PO3G
ester can be considered to comprise (consist essentially of) the compounds
having the
following formulae (IV) and (V):
Rl-C(O)-O-((CH2)30)m((CH2)20)n-R2 (IV)
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R,-C(O)-O-((CH2)3-0)m((CH2)20)nCH2CH=CH2 (V)
wherein R2 is H or R3C(O); each of R, and R3 is individually a substituted or
unsubsti-
tuted aromatic, saturated aliphatic, unsaturated aliphatic, or cycloaliphatic
organic
group containing from 6 to 40 carbon atoms; m and n are in a range such that
the Mn
is within the range of from about 200 to about 10000; and with compounds of
formula
(III) being present in an amount such that the allyl end groups (preferably
all unsatura-
tion ends or end groups) are present in the range of from about 0.003 to about
0.03
meq/g.
Preferably, the PO3G ester has a viscosity which is less than the viscosity of
P03G. Preferred viscosities of PO3G esters range from about 20cS to about 150
cS
at 40 C, and more preferably are about 100cS or less.
Other preferred properties of the PO3G esters can be determined based upon
the preferences stated above for PO3G in and of itself. For example, preferred
mo-
lecular weights and polydispersities are based on the preferred molecular
weights and
polydispersities of the PO3G component of the ester.
Additives in General
Synthetic lube oil compositions in accordance with the present invention com-
prise a mixture of the base stock and one or more additives, where each
additive is
employed for the purpose of improving the performance and properties of the
base
stock in its intended application, e.g., as a hydraulic fluid, a gear oil, a
brake fluid, a
compressor lubricant, a textile and calender lubricant, a metalworking fluid,
a refrigera-
tion lubricant, a two-cycle engine lubricant and/or crankcase lubricant.
The additives can generally be added in amounts based on the type of additive
and desired level of additive effect, which can generally be determined by
those skilled
in the relevant art.
Preferably the additives are miscible in either or both of the PO3G and PO3G
esters.
Preferably, the lube oil additive(s) comprise at least one of ashless
dispersant,
metal detergent, viscosity modifier, anti-wear agent, antioxidant, friction
modifier, pour
point depressant, anti-foaming agent, corrosion inhibitor, demulsifier, rust
inhibitor and
mixtures thereof.
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When the lube oil composition is used as a refrigeration lubricant, the lube
oil
additive(s) preferably comprise at least one of extreme pressure and antiwear
additive,
oxidation and thermal stability improver, corrosion inhibitor, viscosity index
improver,
pour point depressant, floc point depressant, detergent, anti-foaming agent,
viscosity
adjuster and mixtures thereof.
It is intended to be within the scope of the present invention to use any one
or
more of the specified additives alone or in combination with one or more of
the remain-
ing specified additives. It is also within the scope of the present invention
to use more
than one of any specified additive, e.g., one or more friction modifiers,
either alone or
in combination of one or more of the other specified additives, e.g., in
combination with
one or more corrosion inhibitors.
The individual additives may be incorporated into a base stock in any conven-
ient way. Thus, each of the components can be added directly to the base stock
by
dispersing or dissolving it in the base stock at the desired level of
concentration. Such
blending may occur at ambient temperature or at an elevated temperature.
Alternatively, all or some of the additives can be blended into a concentrate
or
additive package that is subsequently blended into base stock to make finished
lubri-
cant. The concentrate will typically be formulated to contain the additive(s)
in proper
amounts to provide the desired concentration in the formulation when the
concentrate
is combined with a predetermined amount of base lubricant.
Non-limiting, illustrative examples of various additives follow.
The ashless dispersant comprises a polymeric hydrocarbon backbone having
functional groups that are capable of associating with particles to be
dispersed. Typi-
cally, the dispersants comprise amine, alcohol, amide and/or ester polar
moieties at-
tached to the polymer backbone often via a bridging group. The ashless
dispersant
may be, for example, selected from salts, esters, amino-esters, amides, imides
and
oxazolines of long chain hydrocarbon substituted mono- and dicarboxylic acids
and/or
their anhydrides, thiocarboxylate derivatives of long chain hydrocarbons, long
chain
aliphatic hydrocarbons having a polyamine attached directly thereto, and
Mannich
condensation products formed by condensing a long chain substituted phenol
with
formaldehyde and polyalkylene polyamine.
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The viscosity modifier (VM) functions to impart high and low temperature oper-
ability to a lubricating oil. The VM used may have that sole function, or may
be multi-
functional.
Multifunctional viscosity modifiers that also function as dispersants are also
known. Illustrative viscosity modifiers are polyisobutylene, copolymers of
ethylene and
propylene and higher alpha-olefins, polymethacrylates, polyalkylmethacrylates,
meth-
acrylate copolymers, copolymers of an unsaturated dicarboxylic acid and a
vinyl com-
pound, inter polymers of styrene and acrylic esters, and partially
hydrogenated co-
polymers of styrene/isoprene, styrene/butadiene, and isoprene/butadiene, as
well as
the partially hydrogenated homopolymers of butadiene and isoprene and iso-
prene/divinylbenzene.
Metal-containing or ash-forming detergents function both as detergents to re-
duce or remove deposits and as acid neutralizers or rust inhibitors, thereby
reducing
wear and corrosion and extending engine life. Detergents generally comprise a
polar
head with long hydrophobic tail, with the polar head comprising a metal salt
of an acid
organic compound. The salts may contain a substantially stoichiometric amount
of the
metal in which they are usually described as normal or neutral salts, and
would typi-
cally have a total base number (TBN), as may be measured by ASTM D-2896 of
from
0 to about 80. It is possible to include large amounts of a metal base by
reacting an
excess of a metal compound such as an oxide or hydroxide with an acid gas such
as
carbon dioxide. The resulting overbased detergent comprises neutralized
detergent as
the outer layer of a metal base (e.g., carbonate) micelle. Such overbased
detergents
may have a TBN of about 150 or greater, and typically from about 250 to about
450 or
more.
Illustrative detergents include neutral and overbased sulfonates, phenates,
sul-
furized phenates, thiophosphonates, salicylates, and naphthenates and other
oil-
soluble carboxylates of a metal, particularly the alkali or alkaline earth
metals, e.g., so-
dium, potassium, lithium, calcium, and magnesium. The most commonly used
metals
are calcium and magnesium, which may both be present in detergents used in a
lubri-
cant, and mixtures of calcium and/or magnesium with sodium. Particularly
convenient
metal detergents are neutral and overbased calcium sulfonates having TBN of
from
about 20 to about 450, and neutral and overbased calcium phenates and
sulfurized
phenates having TBN of from about 50 to about 450.
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Dihydrocarbyl dithiophosphate metal salts are frequently used as anti-wear and
antioxidant agents. The metal may be an alkali or alkaline earth metal, or
aluminum,
lead, tin, molybdenum, manganese, nickel or copper. The zinc salts are most
com-
monly used in lubricating oil in amounts of from about 0.1 to about 10 wt%,
preferably
from about 0.2 to about 2 wt%, based upon the total weight of the lubricating
oil com-
position. They may be prepared in accordance with known techniques by first
forming
a dihydrocarbyl dithiophosphoric acid (DDPA), usually by reaction of one or
more alco-
hol or a phenol with P2S5 and then neutralizing the formed DDPA with a zinc
com-
pound. For example, a dithiophosphoric acid may be made by reacting mixtures
of
primary and secondary alcohols. Alternatively, multiple dithiophosphoric acids
can be
prepared where the hydrocarbyl groups on one are entirely secondary in
character and
the hydrocarbyl groups on the others are entirely primary in character. To
make the
zinc salt any basic or neutral zinc compound could be used but the oxides,
hydroxides
and carbonates are most generally employed. Commercial additives frequently
contain
an excess of zinc due to use of an excess of the basic zinc compound in the
neutrali-
zation reaction.
In one embodiment, however, the lube oil compositions are preferably substan-
tially zinc free.
Oxidation inhibitors or antioxidants reduce the tendency of base stocks to
dete-
riorate 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 hindered phenols, alkaline earth
metal salts
of alkylphenolthioesters having preferably C5 to C12 alkyl side chains,
calcium nonyl-
phenol sulfide, ashless oil soluble phenates and sulfurized phenates,
phosphosul-
furized or sulfurized hydrocarbons, phosphorous esters, metal thiocarbamates,
oil-
soluble copper compounds as described in US4867890, and molybdenum containing
compounds.
Friction modifiers may be included to improve fuel economy. Oil-soluble alkoxy-
lated mono- and di-amines are well known to improve boundary layer
lubrication. The
amines may be used as such or in the form of an adduct or reaction product
with a bo-
ron compound such as boric oxide, boron halide, metaborate, boric acid or a
mono-, di-
or tri-alkyl borate.
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Other friction modifiers are known. Among these are esters formed by reacting
carboxylic acids and anhydrides with alkanols. Other conventional friction
modifiers
generally consist of a polar terminal group (e.g. carboxyl or hydroxyl)
covalently
bonded to an oleophilic hydrocarbon chain. Esters of carboxylic acids and
anhydrides
with alkanols are described in US4702850. An example of another conventional
fric-
tion modifier is organo-metallic molybdenum.
Illustrative rust inhibitors are selected from the group of nonionic polyoxyal-
kylene polyols and esters thereof, polyoxyalkylene phenols, and anionic alkyl
sulfonic
acids.
Copper and lead bearing corrosion inhibitors may also be used. Typically such
compounds are the thiadiazole polysulfides containing from 5 to 50 carbon
atoms, their
derivatives and polymers thereof. Other additives are the thio- and polythio-
sulfena-
mides of thiadiazoles such as those described in UK1560830. Benzotriazole
deriva-
tives also fall within this class of additives.
An illustrative example of demulsifying component is described in
EP-A-0330522. It is obtained by reacting an alkylene oxide with an adduct
obtained by
reacting a bis-epoxide with a polyhydric alcohol.
Pour point depressants, otherwise known as lube oil improvers, lower the
minimum temperature at which the fluid will flow or can be poured. Such
additives are
well known. Typical of those additives which improve the low temperature
fluidity of the
fluid are C8 and C18 dialkyl fumarate/vinyl acetate copolymers,
polyalkylmethacrylates
and the like.
Foam control can be provided by many compounds including an antifoamant of
the polysiloxane type, for example, silicone oil or polydimethyl siloxane.
Some of the above-mentioned additives can provide a multiplicity of effects;
thus, for example, a single additive may act as a dispersant-oxidation
inhibitor. This
approach is well known and does not require further elaboration.
Illustrative, non-limiting examples of additives specific to use in
compression re-
frigeration systems follow.
Extreme pressure additives are known to those skilled in the art, and are used
to provide protection for metal surfaces in applications that occur under
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high pressures. Illustrative extreme pressure and antiwear additives include
phos-
phates, phosphate esters (bicresyl phosphate), phosphites, thiophosphates
(zinc dior-
ganodithiophosphates) chlorinated waxes, sulfurized fats and olefins, organic
lead
compounds, fatty acids, molybdenum complexes, halogen substituted
organosilicon
compounds, borates, organic esters, halogen substituted phosphorous compounds,
sulfurized Diels Alder adducts, organic sulfides, compounds containing
chlorine and
sulfur, metal salts of organic acids.
Illustrative oxidation and thermal stability improvers include sterically
hindered
phenols (BHT), aromatic amines, dithiophosphates, phosphites, sulfides and
metal
salts of dithio acids.
Illustrative corrosion inhibitors include organic acids, organic amines,
organic
phosphates, organic alcohols, metal sulfonates and organic phosphites.
Viscosity index is the measure of the change in viscosity with temperature,
and
a high number suggests that the change in viscosity with temperature is
minimal. In
view of the high viscosity index of the lube oil compositions of the present
invention, it
is possible to formulate a lube oil composition which is free of viscosity
index improver.
However, there may be applications where it is desirable to further improve
viscosity
index. Illustrative viscosity index improvers include polyisobutylene,
polymethacrylate
and polyalkylstyrenes.
Illustrative pour point and or floc point depressants include polymethacrylate
ethylene - vinyl acetate copolymers, succinamic acid - olefin copolymers,
ethylene -
alpha olefin copolymers and Friedel-Crafts condensation products of wax with
naptha-
lene or phenols.
Illustrative detergents include sulfonates, long-chain alkyl substituted
aromatic
sulfonic acids, phosphonates, thiophosphonates, phenolates, metal salts of
alkyl phe-
nols, alkyl sulfides, alkylphenol - aldehyde condensation products, metal
salts of sub-
stituted salicylates, N-substituted oligomers or polymers from the reaction
products of
unsaturated anhydrides and amines and co-polymers which incorporate polyester
link-
ages such as vinyl acetate-maleic anhydride co-polymers.
Illustrative anti-foaming agents are silicone polymers.
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Illustrative viscosity adjusters include polyisobutylene, polymethacrylates,
polyalkylstyrenes, naphthenic oils, alkylbenzene oils, paraffinic oils,
polyesters, polyvi-
nylchloride and polyphosphates.
In the present invention, the additive(s) should be at least partially
(greater than
about 50% by weight) miscible in the base stock. Generally, this means that
the addi-
tives used will be oil soluble at least to some extent, and preferably to a
substantial ex-
tent.
The lube oil composition should thus preferably be a substantially uniform mix-
ture, with substantially no settling or phase separation of components.
The lubrication oil composition preferably comprises the additives in an
amount
of less than 50 wt%, based on the total weight of the lubrication oil
composition. In
various embodiments, the lubrication oil can comprise the additives in an
amount of
about 25 wt% or less, or about 10 wt% or less, or about 5 wt% or less, based
on the
total weight of the lubrication oil composition.
Specific Additive Packaae
In some embodiments, the lubrication oil compositions contain an additive
package comprising a combination at least three different additives (wt% is
based on
total composition weight):
(a) an antiwear additive package comprising from about 0.5 to about 2.0
wt% of a mixture comprising an amine phosphate antiwear additive and a
phosphorothionate antiwear additive, and
(b) from about 0.05 to about 0.5 wt% of methylene
bis(dialkyldithiocarbamate). The methylene bis(dialkyldithiocarbamate) can
function as
an extreme pressure additive and/or an antioxidant.
In alternate embodiments, the antiwear additive package in the lubrication oil
composition contains from about 0.5 to about 1.0 wt% of a mixture comprising
an
amine phosphate antiwear additive and a phosphorothionate antiwear additive.
In alternate embodiments, the additive package contains from about 0.1 to
about 0.3 wt% of the methylene bis(dialkyldithiocarbamate).
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In a preferred embodiment, the lubrication oil compositions further comprise
one or more of the following (wt% is based on total composition weight):
(c) from about 0.05 to about 2.0 wt%, or alternatively from about 0.05 to
about 1.0 wt%, or alternatively from about 0.1 to about 0.5 wt%, of a
tolutriazole
antioxidant/metal passivator additive; and/or
(d) from about 0.05 to about 1.0 wt%, or alternatively from about 0.1 to
about 1.0 wt%, or alternatively from about 0.1 to about 0.75 wt%, of a primary
antioxidant additive package selected from the group consisting of a hindered
amine
antioxidant, a hindered phenol antioxidant and a mixture thereof, and/or
(e) from about 0.05 to about 0.3 wt%, or alternatively from about 0.05 to
about 0.2 wt%, of a calcium sulfonate corrosion inhibitor; and/or
(f) from about 0.01 to about 2.0 wt%, or alternatively from about 0.05 to
about 1.0 wt%, or alternatively from about 0.1 to about 0.5 wt%, of one or a
combination of a thiadiazole metal passivator and a disulfide metal
passivator.
Gear/Hydraulic Lubricants
A preferred use of the lubricant compositions of the present invention is as a
gear/hydraulic lubricant. An exemplary formulation for such a lubricant is as
follows
(wt% is based on total composition):
(a) from about 90 to 99 wt%, or alternatively from about 95 to about 98.5
wt%, of a PTEEG that is fluid at ambient temperature, or a mixture of a PTEEG
and
PTEEG ester that is fluid at ambient temperautre;
(b) an antiwear additive package comprising from about 0.5 to about 2.0
wt%, or alternatively from about 0.5 to about 1.0 wt%, of a mixture comprising
an
amine phosphate antiwear additive and a phosphorothionate antiwear additive;
(c) from about 0.05 to about 0.5 wt%, or alternatively from about 0.1 to
about 0.3 wt%, of a methylene bis(dialkyldithiocarbamate) extreme
pressure/antioxidant additive;
(d) from 0 to about 2.0 wt%, or alternatively about 0.05 to about 2.0 wt%, or
alternatively from about 0.05 to about 1.0 wt%, or alternatively from about
0.1 to about
0.5 wt%, of a tolutriazole antioxidant/metal passivator additive;
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(e) from 0 to about 1.0 wt%, or alternatively from about 0.05 to about 1.0
wt%, or alternatively from about 0.1 to about 1.0 wt%, or alternatively from
about 0.1 to
about 0.75 wt%, of a primary antioxidant additive package selected from the
group
consisting of a hindered amine antioxidant, a hindered phenol antioxidant and
a
mixture thereof,
(f) from 0 to about 0.3 wt%, or alternatively from about 0.05 to about 0.3
wt%, or alternatively from about 0.05 to about 0.2 wt%, of a calcium sulfonate
corrosion inhibitor; and/or
(g) from 0 to about 2.0 wt%, or alternatively from about 0.01 to about 2.0
wt%, or alternatively from about 0.05 to about 1.0 wt%, or alternatively from
about 0.1
to about 0.5 wt%, of one or a combination of a thiadiazole metal passivator
and a
disulfide metal passivator.
EXAMPLES
All parts, percentages, etc., are by weight unless otherwise indicated.
ASTM method D445-83 and ASTM method D792-91 were used to determine
the kinematic viscosity and density of the polymer, respectively.
Additional ASTM methods were used as listed in the Tables below.
The materials of the present invention were tested with and without a lube oil
additive package. The package used during the testing comprised the components
listed in Table 1.
TABLE 1
Additive Description Function Available From
Triphenyl phos- Ciba Specialty
IRGALUBEO phorothionate, typi- Anti- Chemicals,
TPPT cally containing 9% wear/extreme Tarrytown, NY
phosphorus and pressure
9.4% sulfur
VANLUBEO Methylene Ashless anti- RT Vanderbilt
7723 bis(dibutyldithiocarb oxidant and ex- Company Inc.,
amate) treme pressure Norwalk, CT
VANLUBEO Tolutriazole Antioxidant RT Vanderbilt
887E Company Inc.,
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WO 2009/029474 PCT/US2008/073825
Norwalk, CT
PANA Phenyl a- Antioxidant Akrochem, Ak-
naphthalmine ron, OH
VANLUBEO Polymerized 1,2- R.T. Vanderbilt
RD dihydro-2,2,4- Antioxidant Co., Inc., Nor-
trimethylquinoline walk, CT
IRGANOXO Ciba Specialty
1135 Hindered phenol Antioxidant Chemicals,
Tarrytown, NY
IRGALUBEO Mixture of amine EP/AW & cor- Ciba Specialty
349 phosphates rosion inhibitor Chemicals,
Tarrytown, NY
VANLUBEO RT Vanderbilt
8912E Calcium sulfonate Rust inhibitor Company Inc.,
Norwalk, CT
2,5 dimercapto- Corrosion in- RT Vanderbilt
CUVANO 826 1,3,4-thiadiazole hibitor & metal Company, Inc.,
derivative deactivator Norwalk, CT
IRGACOREO Corrosion In- Ciba Specialty
Chemicals,
L12 hibitor Tarrytown, NY
Polydimethylsilox- Defoamer Dow Corning,
ane polymer 200 cSt Midland, MI
LUBRIZOL The Lubrizol
889D Ester copolymer Defoamer Corporation,
Wickliffe, OH
Examples 1-5
Examples 1-5 were prepared by blending the solid ingredients (in pellet form)
in
a PTEEG (made using 25 mol% ethylene glycol) having an Mn as set forth in
Table 2,
either by stirring at 50 C or rotating the mixture in an enclosed jar on a jar
roller mill at
room temperature, over a period of 2 to 3 days. The pellet form of the solid
ingredients
helped avoid air entrainment which occurred when the powder forms were used,
result-
ing in excess foaming. When the mixtures were prepared in an open jar, a
nitrogen
atmosphere was used. Liquid additives were added to the premixed blends,
ensuring
that no solid particles were left undissolved. Table 2 below summarizes the
composi-
tions of these examples.
Table 2: Examples 1 - 5
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WO 2009/029474 PCT/US2008/073825
Ex.1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Polydimethylsiloxane
polymer 0.005 0.0025 0.0025
Lubrizo1889D 0.05 0.05
Vanlube0 7723 0.3 0.3 0.2 0.3 0.3
Vanlube0 887E 0.4 0.4 0.3 0.4 0.4
Irganox01135 0.2 0.2 0.2 0
Irgalube0 TPPT 0.5 0.5 0.5 0.5 0.5
Irgalube0 349 0.4 0.4 0.4 0.4 0.4
Vanlube0 8912E 0.1 0
PANA 0.5 0
Vanlube0 RD 0.25 0.25 0.5 0.5
Irgacore0 L12 0.1 0
CUVANO 826 0.1 0.1 0.1 0.1 0.1
PTEEG (Mn, 98.3 97.85 97.95 97 97.8
SEC/GPC) (993) (1093) (1093) (1040) (993)
The compositions in the Examples were subjected to the tests required for es-
tablishing the standard specifications for industrially acceptable antiwear
gear/hydraulic
oils. The results are shown in Tables 3 and 4.
Table 3. Lubricant Properties of Examples 1-5
Property ASTM Ex.1 Ex.2 Ex. 3 Ex.4 Ex.5
Viscosity Index D-2270 207 206 208 203
Pour Point, C D-97 -45 -45 -48 -42 -48
Flash Point, C D-92 272 288 286 302 294
Four Ball Wear
Scar, mm D-4172 0.3 0.37 0.4 0.59 0.45
Coefficient of
Friction D-4172 0.042 0.033 0.032 0.044 0.051
Load Wear in-
dex D-2783 50.13 61.5 77 77 42.28
Last Nonseizure
Load (scar,mm) D-2783 126 (.49) 160 (.52) 200 (.54) 200 (.52) 100 (.43)
Last Seizure 160kg 160kg
Load (scar,mm) D-2783 (2.78) None None None (2.37)
Weld Load, kg D-2783 200 200 250 250 200
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Falex Pin & V
block Max
Load, lbs D-3233 4250 3000 3000 4250 3500
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Table 4 - Oxidation & Corrosion Test Results (ASTM D4636-190C-24h)
Property Ex.1 Ex. 2 Ex. 3 Ex. 4 Ex. 5
Viscosity Change -11.7 1.49 0.97 6.731 6.5
Acid Number 0.7 0.07 0.09 0.3 0.3
Change (Mg/KOH/g)
Viscosity @ 40 C
Original, cSt 195.1 234.8 238.3 208.1 198.1
, cSt 172.2 238.3 240.6 222.1 210.9
Total Acid #
Original, mg KOH/g 0.22 0.25 0.25 0.42 0.21
, mg KOH/g 0.92 0.32 0.34 0.72 0.51
Copper Corrosion Dull-1 b Dull-1 b Dull-1 b Dull-1 b Dull-1 b
Example 1 contained a minimal amount of antioxidants compared to other ex-
amples (as shown in Table 2). This lubricant showed signs of thermal
degradation (as
shown in Table 4) during Oxidation and Corrosion Test (ASTM D4636) as shown by
the drop in viscosity (-11.7%) and a significant change in acid number (0.7)
after oper-
ating at 190 C for 24h. However this composition showed excellent antiwear and
load
carrying properties (as shown in Table 3) as shown by the very low four ball
wear scar
(0.3mm-ASTM D4172-40kg, 1 200rpm @75 C) and the Falex Pin and V Block test
(Maximum Load 42501bs-ASTM D3233).
Example 2 contained an antioxidant package containing primary antioxidants
including a hindered amine, VANLUBEO RD (0.25 wt%) and a hindered phenol, IR-
GANOXO 1135 (0.2 wt%) in addition to the secondary antioxidant VANLUBEO 7723
(dithiocarbamate). This lubricant showed very little change in viscosity and
negligible
amount of acid number change as tested by ASTM D4636.
Example 3 contained a calcium sulfonate (VANLUBEO 8912E, 0.1 wt%). Co-
incidently, this additive package show excellent load carrying properties as
shown by
the high "Load Wear Index" (77) in spite of the fact that it contains lower
quantity of
VANLUBEO 7723.
Examples 4 and 5, containing 0.5 wt% or more of hindered amine (VANLUBEO
RD & PANA), showed a high viscosity increase compared to the examples
containing
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WO 2009/029474 PCT/US2008/073825
0.25 wt% VANLUBEO RD, although they both showed high load carrying properties
as
indicated by the Falex Load (Table 3)
A negative impact on wear properties was also observed with inclusion of hin-
dered amine in excess of 0.5% (lowest "Four Ball Wear" in the absence of
VANLUBEO
RD).
A low "Coefficient Of Friction" was observed at a VANLUBEO RD level of 0.25
wt%, regardless of other components.
The compositions of the invention provide high load carrying capability (Falex
Load>3000lbs -Table 3), low coefficient of friction and wear.
Also, the antioxidant combination of hindered phenol and hindered amine
provided the best results for oxidation and thermal stability, corrosion and
rust
resistance (Copper Corrosion-1 b) as shown in the Examples.
Compositions containing 0.25 wt% VANLUBEO RD (hindered amine) and 0.2
wt% IRGANOXO 1135 (hindered phenol) showed minimal viscosity and acid number
change for the Oxidation and Corrosion Stability test -ASTM D 4636@190 C-24h.
29
