Note: Descriptions are shown in the official language in which they were submitted.
`'~
2~8~99
Patent
Case EI-6457
JFS:km
HIG~ SU~F~R MINER~L OIL CO~PO8ITIONS
T~C~NICA~ FIELD
This invention relates to reducing the copper corrosivity of
mineral oils having a high content of natural or inherent sulfur
components (i.e., sulfur components that are in the base oil as
produced as distinguished from sulfur compsnents which are deli-
beFately introduced into oil as additives).
BAC~G~OUND
As is well known and documented in the literature, mineral
oils produced or derived from certain petroleum crudes have rela-
tively high inherent sulfur contents, e.g., 0.2 percent by weight
and above. The chemical composition of such sulfur impurities is
diverse and can involve complex molecular structures. For example,
C. J. Thompson in a report entitled "Identification of Sulfur Com-
pounds in Petroleum and Alternate Fossil Fuels" points out that a
twenty year study of certain crude oils culminated in the identi-
fication of some 200 organic sulfur compounds present in the oil.
In his report, which appears at pages 189-208 of "Organic Sulfur
Chemistry", Invited Lectures PresPnted at the 9th International
Symposium on Organic Sulfur Chemistry Riqa, USSR, 9-14 June 1980,
Edited by R. Kh. Freidlina and A. E. Skorova, Pergammon Press,
Copyright 1981, the author makes reference to certain other crude
oils having sulfur contents as high as 13.9, 9.6 and 7.5 percent.
Unfortunately, when high sulfur refined or unrefined mineral
oils (i. e., those containing 0.2% or more of sulfur in the form of
inherent components~ are used as lubricants or functional fluids in
apparatus having so-called yellQw metal parts (copper and copper
alloys such as brass, bronze, etc.~, the sul~ur components tend
strongly to corrode such copper-containing parts. A procedure
widely used for assessing the severity of this corrosive attack is
the copper rod corrosion test forming part of the Cincinnati Mila-
cron Thermal Stability Test Procedura "A". See Cincinnati Milacron
Lubricants Purchase Specification Approved Products Handbook, pages
3-1 to 3-3. A similar procedure has recently been issued by ASTM
as ASTM D2270. This recent procedure is based on the foregoing
Cincinnati Milacron procedure. The Cincinnati Milacron "A" test
involves llse of a rating scale which extends from 1 to 10. A ra-
208~199 EI-6457
ting of 5 or below ls regarded as a pass, and the lower the
nu~erical rating, the better. Conversely any rating above 5 is an
unsatisfactory result and the higher the numerical rating above 5,
the worse the result.
The discovery of an effective, low-cost way of reducing the
corrosiveness of high sulfur mineral oils and mineral oil blends
without eliminating or reducing the sulfur content of the oil would
be a welcome contribution to the art. Such a contribution would
conserve natural resources, reduce processing costs, and enhance
perfo~mance and/or durability of engines and other mechanical
apparatus utilizing high sulfur minerals oils as lubricants or
functional fluids that are in contact, continuously or intermit-
tently, with metal parts, especially readily-corroded metal parts
such as those made of yellow metals and the like.
This in~ention is deemed to constitute such a contribution.
T B INV~NTION
This invention involves, inter alia, the discovery that it is
possible to reduce the corrosiveness of high sulfur content mineral
oils by use of small quantities of certain trivalent organic phos-
phorus additives, viZo ~ oil-soluble neutral hydrocarbyl phosphites.
By ~Ineutral~ is meant that the phosphite ester does not contain
free unesteri~ied acid functionality (i.e., it has no -OH or -SH
gr~ups~. ~oreover, it has been found that in at least some cases
neutral hydrocarbyl phosphite esters can be used in extrem~ly low
concentrations in normally corrosiYe high sulfur oils, and yet
provide a finished lubricant composition exhibiting very littl2
corrosiveness toward copper.
Thus in one of its forms this in~ention provides an oil-based
lubricant or functional fluid composition a major proportion of
which is formed from a base mineral oil tha-t has an inherent sulfur
content of at least 0.2 percent by weight, said composition con-
taining a minor amount of at least one oil-soluble neutral hydro-
carbyl phosphite, said composition being characteriæed in that it
exhibits a copper rod rating of 5 or below in the Cincinnati Mila-
cron Thermal Stability test procPdure in the for~ referred to in
the specification hereof and in that in the absence of said phos-
phite, said composition exhibits a copper rod rating above 5 in
said Cincinnati Milacron test procedure. In this embodiment an oil
which fails the Cincinnati Milacron copper rod test is transformed
by this invention into one that passes this test, preferably with
2 ~ 9
EI-6457
a rating of 3 or below, more preferably with a rating of 2 or be-
low, and most preferably with a rating of 1.
In another embodiment this invention provides a mineral oil
composition characteri~ed in that (i) the mineral base oil of the
composition has an inherent sul~ur content of 0.2% by weight or
above, (ii) in the absence of a phosphite ester, said mineral base
oil exhibits a copper rod rating below 5 in the Cincinnati Milacron
Thermal Stability test, and (iii) the compositian contains a corro-
sion-inhibiting amount o~ at least one oil-soluble neutral hydro-
carbyl phosphite and exhibits a copper rod rating that is reduced
by one or more numerical units of the rating scale as compared to
the rating of said base oil in the absence of a phosphite ester.
In this embodiment, a high sulfur oil which passes the Cinrinnati
Milacron copper rod test is transformed by this invention into one-
that exhibits even better corrosion resistance in the test, prefer-
ably with a rating of 3 or below, more preferably with a rating of
2 or below, and most preferably with a rating o~ 1.
While any oil-soluble sulfur-free neutral hydrocarbyl phos-
phite ester has the potential of decreasing the copper corrosivity
o~ one or more mineral oils having an inherent sulfur content of
0.2% by weight or above, the use of oil-soluble, sulfur-free,
neutral (i.e., fully esterified) hydrocarbyl monophosphites (i.e.,
one phosph~rus atom per molecule) and/or diphosphites (i.e., two
phosphorus atoms per molecule), and especially trihydrocarbyl phos-
phites is preferred. Thus use can be made of such compounds as
trimethyl phosphite, triethyl phosphite, tripropyl phosphite, tri-
isopropyl phosphite, tributyl phosphite, triisobutyl phosphite,
triamyl phosphite, trihexyl phosphite, triheptyl phosphite, tri--
octyl phosphite, triisooctyl phosphite, txis~2-ethylhexyl) phos-
phite, trinonyl phosphite, tridecyl phosphite, triisodecyl phos-
phite, trilauryl phosphite, tris(tridecyl) phosphite, triallyl
phosphite, trioleyl phosphite, tricyclohexyl phosphite, tribenzyl
phosphite, tris(phenethyl) phosphite, phenyl dimethyl phosphite,
phenyl diisodecyl phosphite, diphenyl isooctyl phosphite, diphenyl
isodecyl phosphite, bis(2,4-di-tert butylphenyl) pentaerythritol
diphosphite, distearyl pentaerythritol diphosphite, phenyl neopen-
tylene glycol phosphite, tetraphenyl dipropyleneglycol diphosphite,
~etra C121$ alkyl 4,4'-isopropylidenediphenol diphosphit~, diiso-
decyl pentaerythritol diphosphite, and the like. In general, each
hydrocarbyl group may contain up to about 50 carbon atoms or more,
provided only that the compound is sufficiently soluble in the oil
to accomplish the corrosion inhibition objectives of this inven-
tion. Triaryl phosphites are generally the most efIQctlre for the
2 ~ 9
EI-6457
purposes of this invention, and thus are preferred. Examples
include cresyl diphenyl phosphite, tricresyl phosphite, trixylyl
phosphite, tris(nonylphenyl) phosphite, trinaphthyl phosphite, and
in general any oil-soluble triaryl phosphite in which each aryl
group contains from 6 to a~out 24 carbon atoms, more preferably 6
to about 18 carbon atoms, and especially where the aryl hydrocarbyl
group is phenyl or alkyl-substituted phenyl. Triphenyl phosphite
is the most preferred additive because of its excellent performance
characteristics, commercial availability, purity, and low cost.
The neutral phosphites are used in small amounts sufficient to
decrease the copper corrosivity as assessed, for example, by the
copper rod test of the Cincinnati Milacron test procedure. The
amount used will thus vary depending upon the amount and character
of the inherent sulfur components in the oil, the responsiveness of
the oil to copper corrosion inhibition, the molecular weight of the
neutral phosphite(s) being employed, and the extent to which it is
desired to reduce the copper corrosiveness of the particular oil.
Typically amounts of up to 0.05% by weight are sufficient but high-
er amounts can be used whenever deemed necessary or desirable.
Preferably, the amount used falls in the range of about 0.01 to
about 0.03 wt %.
Not all oils respond to use of neutral hydrocarbyl phosphite
copper corrosion inhibitors pursuant to this invention. The reason
~or this is not known, but presumably relates in some way or other
to the chemical structure~s) of the inherent sulfur component~s)
present in the oil. Thus there is no presently-known wa~ by which
it can be predicted whether a given oil will or will not respond to
use therein of a neutral hydrocarbyl phosphite copper corrosion
inhibitor pursuant to this invention other than to conduct a pilot
experiment with the particular high sul~ur mineral oil. For this
purpose, the Cincinnati Milacron copper rod test is used and in-
deed, is recommended for use, although other equivalent pro~edures
may be found useful and can be used, if desired. Once a represen-
tative sample of a given high sulfur mineral oil has been found to
respond to addition of one or more neutral hydrocarbyl phosphites,
the remainder of such oil can be treated pursuant to this invention
and thereby rendered resistant to copper corrosiveness.
The unpredictability of this invention is thus shown by the
fact that not all high sulfur oils respond to the treatment, and no
explanation for the divergence of results is presently known.
2 ~ 9
EI-64S7
The compositions of this invention preferably contain, in ad-
dition to the hydrocarbyl phosphite ester(s), (a) one or more oil-
soluble metal salts of one or more dihydrocarbyl phosphorodithioic
acids, preferably one or more zinc dihydrocarbyl dithiophosphates,
S (b) one or more antioxidants, (c) one or more rust inhibitors,and/or (d) one or more demulsifiers. Compositions containing at
least any two or any three of (a), (b), (c) and (d) are more pr~-
ferred. Most preferably the compositions of this invention contain
all of (a), (b), (c) and (d).
The oil-soluble metal salts of one or more dihydrocarbyl phos-
phorodithioic acids that can be employed in the compositions of
this invention are salts in which the metal is a Group II metal,
aluminum, tin, iron, cobalt, lead, molybdenum, manganese, nickel or
copper, While various hydrocarbyl groups can be present in these
salts, the hydrocarbyl groups are preferably primary or secondary
alkyl groups (or a combination of primary and secondary alkyl
groups), and most preferably are all primary alkyl groups. The
preferred salts are the zinc salts, and although any oil-soluble
zinc dihydrocarbyl dithiophosphate can be used as component (a), it
is particularly preferred to employ an overbased zinc dihydrocarbyl
dithiophosphate, especially a zinc dialkyldithiophosphate wherein
the alkyl groups are primary alkyl groups, containing from 6 to 10
carbon atoms each, especially 8 carbon atoms each, and wherein the
overbased to neutral ratio is O.96 or above as determined by 31p:
~5 nmr. In this connection, overbased species appear in the range of
about 103 to about 105 ppm whereas neutral species appear in the
range o~ about 100 to about 102 ppm and the signals are integrated
in the usual manner to calculate the overbased : neutral ratio.
Additionally the impurity content in the zinc dihydrocarbyl dithio-
phosphate should be very low. Preferably at about 80 ppm, the 31p
nmr should provide an integrated spectrum showing less than about
0.25 area percent phosphorus. Also, it is preferable that at about
5 to about 15 ppm, the integrated 31p nmr spectrum will show virtu-
ally no phosphate impurities. Likewisa virtually no impurities
should apyear at 95 to 98 ppm in the integrated spectrum. It is
also preferable to use zinc dihydrocarbyl dithiophosphates which
exhibit a copper weight loss in the AST~ D2619 procedure of 0.70
maximum. Zinc di-(2-ethylhexyldithiophosphate) meeting the above
criteria is especially preferred, particularly when employed in a
formulation of other components such as in Example 3 hereinafter.
Other metal salts of dihydrocarbyl phosphorodithioic acids
including other zinc dihydrGcarbyl dithiophosphates which may be
~8~
EI-6457
used in the compositions of this invention are referred to herein-
after.
While various oil-soluble antioxidants can be used, it is pre-
ferred to use a combination of (l) a hindered phenolic antioxidant
such as a mixture of tertiary butyl phenols containing at least
about 75% and preferably at least about 85% 2,6-di-tert-butylphe-
nol, such as Ethyl~ 735 antioxldant, and (2) a secondary aromatic
amine antiaxidant such as bis(4-alkylphenyl)amines wherein the
alkyl groups contain from 6 to 12 carbon atoms and preferably are
branched chain alkyl groups, such as Naugalube 438L antioxidant, a
product i~ which the alkyl groups are branched octyl groups. The~
proportions of the phenolic antioxidant to the aromatic amine
antioxidant are preferably in the range of about 3-14 parts by
weight of the phenolic antioxidant per part by weight o the amine
antioxidant. Preferred proportions are in the range of about 5 to
about 10 parts by weight, and more pre~erably about 6 to about 8
parts by weight, of the phenolic antioxidant per part by weight of
the amine. Other antioxidants suitable for use in the practice of
this invention are referred to hereinafter.
All sorts of rust inhibitors can be employed in the composi-
tions of this invention, and further reference to such materials
appears hereinafter. However the preferred materials comprise a
combination of (1) a modi~ied imidazoline rust inhibitor, such as
HI~EC~ 536 additive (Ethyl Petroleum Additivas, Inc.; Ethyl Petro-;
leum Additives, Ltd.; Ethyl S.A.; Ethyl Canada Limited); (2) one or
more overbased alkaline earth metal alkyl phenates having a TBN
~ASTM D2896~ of over 200, most preferably a calcium alkyl ph~nate
with a TBN of at least about 250, such as OLOA 219, Chevron Chemi-
cal Compa~y; and (3) one or more alkaline earth dihydrocarbyl naph-
thalene sulfonates, mo t pre~erably a calcium dialkyl naphthalene
sulfonate wherein the alkyl groups each contain 6 to 12 carbon
atoms, most ~re~erably 9 carbon atoms, such as NA-SUL~ 729 inhi-
bitor. The proportions of (1) : ~2) : (3) are preferably in the
rang~s of about 3-10 parts by weight o~ (1), and 2~7 parts by
weight of (Z) per part by weight of (3).
The demulsifier(s) used in the preferred compositions of this
invention can likewise be varied. The preferred materials for the
use are, however, liquid nonionic surface active agents, such as
the amine glycol condensates such as are available under the TRITON
trademark of Rohm & Haas Company. A particularly preferred materi-
al of this type is TRITON CF-32 which is described by the manufac-
turer as composed of 95% active component(s) ar~d 5~ water which is
208~199 EI-6457
a pale yellow liquid having a Brookfield viscosity at 2SC of 550
cP, a specific gravity of 1.03 at 25C, a density of 8.6 lb/gal, a
pH (5% aqueous solution) of 9.5~11, a flash point (TOC) of < 300F,
and a pour point of 15F (-9C). Examples of other demulsifiers
s which can be used are referred to hereinafter.
The practice of this invention is illustrated by, but is not
limited to, the following examples wherein all parts and percen-
tages are by weight.
;
EXAMPLE 1
An additive concentrate is formed by blending together the
following components: 53.33~ zinc di-2-ethylhexyl dithiophosphate
(Elco 10~); 22.67% ETHYL~ antioxidant 735 (a mixture of tertiary
butyl phenols containing approximately 85% 2,6-di-tert-butyl phe-
nol, 11% 2,4,~-tri-tert-butyl phenol, 2% 2,4-di-tert-butyl phenol,
2% other phenols); 4.67% 4,4'-bis(tert-nonyl)-1,1'-diphenylamine
(Naugalube 438L); 1.33% overbased calcium sulfurized phenate (OLOA
219, a pro~uct indicated by the manufacturer, Chevron Chemical
Company, to have 2 TBN (ASTM D2896) of 254, a calcium content of
9. 5% and a sulfur content of 3.73%); 1.33% calcium dinonylnaph-
thalene sulfonate as a 50% solution in light mineral oil (NA-SUI~
729 additive); 6.67% modified imidazoline rust inhibitor (HiTEC~'
536 additive, a product indicated by the suppliers thereof, Ethyl
Petroleum Additives, Inc, Ethyl Petroleum Additives, Ltd., Ethyl
S.A., Ethyl Canada Limited, to have a neutralization number in the
range of 51 to 61 mg KOH/g, typically 56; a typical specific
gravity of 0.92 to 0.94; a typical viscosity at 100C of 36 cSt);
0.4% amine polyglycol condensate nonionic surface active agent
(TRITON~ CF~32, a product indicated by the manufacturer, Rohm ~
Haas Company, to be a mixture of 95% active and 5% water having a
Brookfield Viscosity @ 25C of 550 cps, a specific gravity Q 25C
of 1.03, a pH of 9.5-11, a flash point (TOC) >300F and a pour
point of 15F (-9C); 2.67% triphenyl phosphite; and 6.93% process
oil diluent. The concentrate contains 0.2% calcium, 4.1% phospho-
rus, 4.2% zinc, and 8.1% sulfur, and has the following typical pro-
perties: viscosity at 40C of 48.95 cSt, viscosity at 100C of 6.02
cSt, specific gravity (15.6/15.6C) of 0.995 and a flash point (P-M
C) of 126). The concentrate can be employed in hydrocarbon based
functional fluids such as hydraulic fluid at concentrations in the
range of about 0.50 to about 1.25~, a preferred treat level being
0.75~.
EXAMPLE 2
208~199 EI-6457
An additive concentrate is formed by blending together the
following components: 41.76% zinc di-2-ethylhexyl dithiophosphate
(Elco 108); 18.9~% ETHYL~ antioxidant 735 (a mixture of tertiary
butyl phenols containing approximately 85% 2,6-di-tert-butyl phe-
nol, 11~ 2,4,6-tri-tert-butyl phenol, 2% 2,4-di-tert-butyl phenol,
2% other phenols); 4.0% 4,4'-~is(tert-nonyl)-1,1'-diphenylamine
(Naugalube 438L); 0.82% calcium dinonylnaphthalene sulfonate as a
50% solution in light mineral oil (NA-SUL~ 729 additive); 10.0%
modified imidazoline rust inhibitor (HiTEC~ 536 additive, a product
indicated by the suppliers thereof, Ethyl Petroleum Additives, Inc,
Ethyl Petroleum Additives, Ltd., Ethyl S.A., Ethyl Canada Limited,
to have a neutralization number in the range of 51 to 61 mg KOH/g,
typically 56; a typical specific gravity of 0.92 to 0.94; a typical
viscosity at 100C o~ 36 cSt); 6.47% sulfurized sperm oil replace-
ment (SUL-PERM 10S, a product indicated by the manufacturer there-
of, Keil Chemical Division of Ferro Corporation, to contain 9.5%
sulfur and to have the following properties: a viscosity at 100~F
of 2000 SUS, a viscosity at 210F of 210 SUS, a specific gravity at
77F of 0.9844 and to exhibit an ASTM D130 rating of lA~; 0.35%
poly~oxyethylene)-poly(oxypropylene~ derivative of ethylene diamine
(a product marketed by BASF Corporation as TETRONIC 15Ql and as
P~URADYNE F~5151, and indicated to have the following typical pro-
perties: a molecular weight of 7900, a specific gravity (25/25C)
of 1.02, a Brookfield Viscosity of 1170 cps at 25QC, a pour point
of -4C, and a refractive index at 25C o~ 1.4537); 2.35% triphenyl
phosphite; and 15.29% process oil diluent. The concentrate can be
employed in hydrocarbon based functional fluids such as hydraulic
fluid at concentrations in the range of about 0.50 to about 1.25%,
a preferred treat level being 0.85%.
EXAMPLE.3
An additive concentxate is formed by blending together the
following components: 42.67% zinc di-2-ethylhexyl dithiophosphate
(HiTEC 678 additive, Ethyl Petroleum Additives, In~; Ethyl Petro-
leum Additives, Ltd.; Ethyl S oA~; Ethyl Canada Limited); 28.33%
ETHYL~ antioxidant 735 (a mixture of tertiary butyl phenols con-
taining approximately 85% 2,6-di-tert-butyl phenol, 11% 2,4,6-tri-
tert-butyl phenol, 2% 2,4-di-tert-butyl phenol, 2% other phenols);
5.83% 4,4'-bis(tert-nonyl)-1,1'-diphenylamine (Naugalube 438L);
5.83% overbased calcium sulfurizPd phenate (OLOA 219, a product
indicated by the manufacturer, Chevron Chemical Company, to have a
TBN (AS~M D2896) of 254, a calcium content of 9.25% and a sulfur
content of 3.73%); 8.33% modified imidazoline rust inhibitor
(HiTEC~ 536 additive, a pro~uct indicated by the suppliers thereof,
Ethyl P~troleum Additlves, Inc, Ethyl Petroleum Additives, Ltd.,
-- 8
2~8~99
EI-6457
Ethyl S.A., Ethyl Canada Limited, to have a neutralization number
in the range of 51 to 6~ mg KO~/g, typically 56; a typical specific
gravity of 0.92 to 0.94; a typical viscosity at 100C of 36 cSt);
0.5% amine polyglycol condensate nonionic surface active agent
(TRITON0 CF-32, a product indicated by the manufacturer, Rohm &
Haas Company, to be a mixture of 95% active and 5% water having a
Brookfield Viscosity @ 25C of 550 cps, a specific gravity @ 25/C
of 1.0~, a pH of 9.5-11, a flash point (TOC) >300F and a pour
point of 15F (-9C); 0.25% poly(oxyethylene)-poly(oxypropylene)
derivative of ethylene diamine (a product marketed by BASF Co~pora-
tion as TETRONIC 1501 and as PLURADYNE FL5151, and indicated to.
have the following typical properties: a molecular weight of 7900,
a specific gravity (25/25C) of 1.02, a Brookfield Viscosity of
1170 cps at 2~C, a pour point of -4C, and a refractive index at.
2SC of 1.4537); 3.33% modified imidazoline corrosion inhibitor-
with a nitrogen content in the range of about 5.5 to about 5.8 and
a boiling point of approximately 305F (~ONAMULSE CI, a product:
supplied by Mona Industries and indicated by the supplier to have
the following typical properties: a specific gravity @ 25C of:
approximately O.959, an acid number in the range of 0-2, and an
alkali number in the range of 100-120); 3.33% triphenyl phosphite;
and 1.6$ process oil diluent. The concentrate can be employed in,
hydrocarbon based functional fluids such as hydraulic fluid at con-
centrations in the range of about 0.50 to ahout 1.25%, a prsferred.
treat level being 0.60%.
EXAMPLE 4
The procedure of Example 3 i5 repeated substituting 7.9% of
tridecylphosphite for the triph~nyl phosphite, and for best results
increasing all treat levels referred to in Example 3 by an addi-
tional 0.03%.
EX~MPLE 5
The procedure of Example 3 is repeated substituting 10.8% of
tributylphosphite for ~he triphenyl phosphite, and for best results
increasing all treat levels referred to in Example 3 by an addi-
tional 0.05%.
EXAMPLE 6
The procedure of Example 3 is repeated substituting 20.5% of
tris(2-ethylhexyl)phosphite for the triphenyl phosphite, and for
best results increasing all treat levels referred to in Example 3
by an additional 0.13%.
2 ~ 9
EI-6457
EXAMPLE 7
An additive concentrate is formed ~y blending toyether the
following components: 53.33% zinc di-2-ethylhexyl dithiophosphate
(Elco 108); 19.0% ETHYL~ antioxidant 735 (a mixture of tertiary
butyl phenols containing approximately 85% 2,6-di-tert-butyl phe-
nol, 11% 2,4,6-tri-tert-butyl phenol, 2% 2,4-di-tert-butyl phenol,
2% other phenols); 4.00% 4,4'-bis(tert-nonyl)-1,1'-diphenylamine
(Naugaluhe 438L); 0.8% calcium dinonylnaphthalene sulfonate as a
50~ solution in light mineral oil (NA-SUL~ 729 additive); 9.96%
modi~ied imidazoline rust inhibitor (HiTEC~ 536 additive, a product
indicated by the suppliers thereof, Ethyl Petroleum Additives, Inc,
Ethyl Petroleum Additives, Ltd., Ethyl S.A., Ethyl Canada Limited,
to have a neutralization number in the range of 51 to 61 mg KOH/g,
typically 56; a typical specific gravity of 0.92 to 0.94; and a
typical viscosity at 100C of 36 cSt); 0.39% amine polyglycol con-
densate nonionic surface active agent (TRITON~ CF-32, a product
indicated by the manufacturer, Rohm & Haas Company, to be a mixture
of 95% active and 5% water having a Brookfield Viscosity Q 257C of
550 cps, a specific gravity @ 25C of 1.03, a pH of 9.5-11, a flash:
point (TOC) >300F and a pour point of 15F (-9C); 6.47~ sulfur-
ized sperm oil replacement ~SUL-PERM lOS, a product indicated by
the manufacturer thereof, Keil Chemical Division of Ferro Corpor-
ation, to contain 9.5% sulfur and to have the following properties:
a viscosity at 100F of 2000 SUS, a viscosity at 210F o~ 210 SUS,
a specific gravity at 77F of 0.9844 and to exhibit an AST~ Dl30
rating of lA); 3.33% triphenyl phosphite; and 2.72% process oil
diluent. The concentrate can be employed in hydrocarbon ~ased
~unctional fluids such as hydraulic fluid at concentrations in the
range of about 0.60 to about 1.5%, a preferred treat level being
0.85%.
As noted above, the inclusion in the formulated high sulfur
oils of a fully esterified monophosphite or diphosphite can reduce
very substantially the copper corrosiveness of the resultant com-
position. For example, when a hydraulic oil of ISO viscosity grade
68 from a well known petroleum refiner with an inherent sulfur con-
tent of 0.43~ was treated with an additive concentrate as described
in Example 3 above such that the oil contained 0.02% by weight of
the triphenyl phosphite, the Cincinnati Milacron copper rod ratings
(triplicate runs) were in the range of 1-2. On the other hand, the
same oil containing the same total concentration of a corresponding
additive concentrate which did not contain any phosphite ester, the
copper rod ratings (triplicate runs~ were in the range of 6-7.
Similarly, when the same hydraulic oil was treated with the
additive concentrate of Example 4 above such that thP con~ent o~`
- 10 -
~8~99 EI--6457
tridecyl phosphite in the oil was 0.05%, the copper rod ratings in
the triplicate runs were reduced from 6-7 to 2. The same oil with
0.07% of tributyl phosphite as the additive concentrate of Example
~ above brought the copper rod ratings down from 6-7 to 3. The
same improvement wa~ achieved in the same base oil with 0.15% of
tris(2-ethylhexyl) phosphite as the additive concentrate of Example
6.
When the above high sulfur hydraulic oil was treated with the
concentrate of Example 7 in amount such that the oil contained
0.02% of triphenyl phosphite, the copper rod ratings (run in
triplicate) were in the range of 1-2 whereas the corresponding
additive concentrate which did not contain phosphite ester yielded
triplicatP copper rod ratings in the range of 7-8 when tes~ed in-
the same base oil.
When the additive concentrate of Example 1 was used in the
above high sulfur hydraulic oil at a treat rate of 0.75 (whereby
the triphenyl phosphite content of the oil was 0.02%) the following:
results were obtained in the Cincinnati Milacron Thermal Stability
Test (average of 3 runs):
___ _ _i . _ - !
20 Property Pass/Fail Point Test Results
_ ~ _ !
Copper Rod Rating 5 Maximum 1-2
I , _ _
¦Copper Welght Loss lu 9/~ l.l I
Iron Appearance 1 Maximum 1 ¦~
_ . - -- 11
Iron Weight Loss 10 mg Maxlm~m O.4 ¦ .
25Total Sludge 100 mg Maximum 4.1 i
As also noted above, not all high sulfur oils respond favora-
bly to the inclu~ion therein of a phosphite ester. For example in
a mineral oil having an inherent sul~ur content of 0.40% and an IS0
viscosity grade 32 from a second well known petroleum refiner,
0.02% of triphenyl phosphite as the additive concentrate of Example
7 gave triplicate copper rod ratings in the range of 9-10. Yet in
a mineral oil having an inherent sulfur content of 0.35% and an IS0
viscosity grade 68 from a third well known petroleum refiner, 0.02%
of triphenyl phosphite as the additive concentrate of Example 7
gavP triplicate copper rod ratings in the range of 1-2, as compared
to ratings in the range of 4-5 when the oil was treated with the
corresponding phosphite-free additive concentrate.
-- 11 --
2 08 ~1 9~ EI-6457
As pointed out hereinabove, the compositions of this invention
preferably contain one or more additional components, such as (a)
one or more oil-soluble metal salts of one or more dihydrocarbyl
phosphorodithioic acids, preferably one or more zinc dihydrocarbyl
dithiophosphates, (b) one or more antioxidants, (c) one or more
rust inhibitors, and/or (d) one or more demulsifiers.
(a) _ al Salts_of Dihvdrocarbyl Phosphorodithioic Acids
As is well known, metal hydrocarbyl dithiophosphates are
usually prepared by reacting phosphorus pentasulfide with one or
more alcohols or phenolic compounds or diols to produce a hydro-
carbyl dithiophosphoric acid which is then neutralized with one or
more metal-containing bases. When a monohydric alcohol or phenol
is used in this reaction, the final product is a metal dihydrocar-
byl dithiophosphate. On the other hand, when a suitable diol
(e.g., 2,4-pentanediol) is used in this reaction, the final product
is a metal salt of a cyclic hydrocarbyl dithiophosphoric acid.
See, for example, U.S. Pat. No. 3,089,850, the disclosure of which
is incorporated herein by reference. Thus typical oil-soluble
metal hydrocarbyl dithiophosphates used as component a) may be~
represented by the formula
S
~ --S M
R 2 x
where R1 and R~ are, independently, hydrocarbyl groups or taken
together are a single hydrocarbyl group ~orming a cyclic structure
with the phosphorus and two oxygen atoms, preferably a hydrocarbyl-
substituted trimethylene group of sufficient carbon content to
render the compound oil soluble~ M is a metal, and x is an integer
corresponding to the valence of M. The preferred compounds are
those in which R1 and R2 are separate hydrocarbyl groups (i.e., the
metal dihydrocarbyl dithiophosphates). Usually the hydrocarbyl
groups of the metal dihydrocarbyl dithiophosphates will contain no
more than about 50 carbon atoms each although even higher molecular
weight hydrocarbyl groups can be present in the compound. The hy-
drocarbyl groups include cyclic and acyclic groups, both saturated
and unsaturated, such as alkyl, cycloalkyl, alkenyl, cycloalkenyl,
aryl, cycloalkylalkyl, aralkyl, and the like. It will be under-
stood that the hydrocarbyl groups may contain elements other than
carbon and hydrogen provided such other elem&nts do not detract
- 12 -
2~ 8~ ~ EI-6457
from the predominantly hydrocarbonaceous character of the hydrocar-
byl group and do not adversely affect the copper corrosion resis-
tance lmparted to the composition pursuant to this invention. Thus
the hydrocarbyl groups may contain ether oxygen atoms, secondary or
tertiary amino ni~rogen atoms, and/or inert functional groups such
as esterified carboxylic groups, keto groups, and the like.
The metals present in the oil-soluble metal dihydrocarbyl
dithiophosphates and oil-soluble metal cyclic hydrocarbyl dithio-
phosphates can include such metals as lithium, sodium, potassium,
copper, magnesium, calcium, zinc, strontium, cadmium, barium, mer-
cury, aluminum, tin, lead, chromium, molybdenum, tungsten, mangan-
ese, iron, cobalt, nickel, ruthenium, etc., as well as combinations
of two or more such metals. Of the foregoiny, the salts containing
group II metals, aluminum, lead, tin, molybdenum, manganesQ, co--
balt, nickel and/or copper, are preferred. The dihydrocarbyl di-
thiophosphates of zinc and copper are particularly preferred, with
the zinc salts being the most preferred type of metal compound for
use in the compositions of this invention.
The phosphorodithioic acids from which the metal salts ar~
formed can be prepared by the reaction o~ about 4 moles of one or
more alcohols (cyclic or acyclic) or one or more phenols or mixture
of one or more alcohols and one or more phenols (or about 2 moles
of one or more diols) per mole of phosphorus pentasulfide, and the
reaction may be carried out within a temperature range of ~rom
about 50 to about 200C. The reaction generally is completed in
about 1 to lO hours. Hydro~en sulfide i5 lib2rated during the
reaction.
Another method for the preparation of the phosphorodithioic
acids involves reaction of one or more alcohols and/or one or mora
phenols with phosphorus sesquisulfide in the presence of sul~ur
such as is described in PCT International Publication No. WO
90/07512, all disclosure of which is incorporated herein by refe-
rence. This reaction is conducted at an elevated temperature,
preferably in the range of 85-150C with an overall atomic P:S
ratio of at least 2.5:1.
The alcohols used in forming the phosphorodithioic acids by
either of the above methods are praferably primary alcohols, or
secondary alcohols. Mixtures thereof are also suitable. The
primary alcohols include propanol, butanol, isobutyl alcohol,
pentanol, 2-ethyl-1-hexanol, isooctyl alcohol, nonanol, decanol,
undecanol, dodecanol, tridecanol, tetradecanol, octddecano' r eico~
- 13 -
2 ~ 9 ~
EI 6457
sanol, and the like. The primary alcohols may contain various
substituent groups such as halogen atoms, nitro groups, etc., -~hich
do not interfere with the desired reaction. Among suitable secon-
dary alcohols are lncluded 2~butanol, 2-pentanol, 3-pentanol, 2-
hexanol, 5-methyl-2-hexanol, and the like. In some cases, it is
preferable to utilize mixtures of various alcohols, such as mix-
tures of 2-propanol with one or more higher molecular weight
primary alcohols, especially primary alcohols having from 4 to
about 13 carbon atoms in the molecule. Such mixtures preferably
contain at least 10 mole percent of 2-propanol, and usually will
contain from about 20 to about 90 mole percent of 2-propanol. In
one preferred embodiment, the alcohol comprises about 30 to 50 mole
percent of 2-propanol, about 30 to 50 mole percent isobutyl alcohol
and about 10 to 30 mole percent of 2-ethyl-1-hexanol.
Other suitable mixtures of alcohols include 2-propanol/butan-
ol; 2-propanol/2-butanol; 2-propanol/2-ethyl-1-hexanol; butanol/2-
ethyl-l-hexanol; isobutyl alcohol/2-ethyl-1-hexanol; and 2-propan-
ol/tridecanol.
Cycloaliphatic alcohols suitable ~or use in the production of
the phosphorodithioic acids include cyclopentanol, cyclohexanol,
methylcyclohexanol, cyclooctanol, borneol and the like. Prefera-
bly, such alcohols are used in combination with one or more primary
alkanols such as butanol, isobutyl alcohol, or the like.
Illustrative phenols which can be employed in forming the
phosphorodithioic acids include phenol, o cresol, m-cresol, p-
cresol, 4-ethylphenol, 2,4 xylenol, and the like. It is desirable
to employ phenolic compounds in combination with primary alkanols
such propanol, butanol, h~xanol, or the like.
other alcohols which can be ~mployed include benzyl alcohol,
cyclohexenol, and their ring-alkylated analogs~
It will be appreciated that when mixtures of two or more al-
cohols and/or phenols are employed in forming the phosphorodithioic
acid, the resultant product will normally comprise a mixture of
three or more dif~erent dihydrocarbyl phosphorodithioic acids, usu-
ally in the form of a statistical distribution in relation to the
number and proportions of alcohols and/or phenols used.
Illustrative diols which can be used in forming the phospho-
rodithioic acids include 2,4-pentanediol, 2,4-hexanediol, 3,5-
- 14 -
2~8~1~9
EI-6457
heptanediol, 7-methyl-2,4-octanediol, neopentyl glycol, 2-butyl-
1,3-propanediol, 2,2-diethyl-1,3-propanediol, and the like.
The preparation of the metal salts of the dihydrocarbyl di-
thiophosphoric acids or the cyclic hydrocarbyl dithiophosphoric
acids is usually effected by reacting the acid product with a
suitable metal compound such as a metal carbonate, metal hydrox-
ide, metal alkoxide, metal oxide, or other appropriate metal salt.
Simply mixing and heating such reactants is normally sufficient to
cause the reaction to occur and the resulting product is usually of
sufficien~ purity for use in the practice of this invention. Typi-
cally, the salts are formed in the presence of a diluent such as an
alcohol, water or a light mineral oil. Neutral salts are prepared
by reacting one equivalent of metal oxide or hydroxide with one
equivalent of the acid. Basic metal salts are prepared by adding
an excess (i.e., more than one equivalent) of the metal oxide or
hydroxide with one equivalent of the dihydrocarbyl phosphorodithi-
oic acid or cyclic hydrocarbyl phosphorodithioic acid.
Illustrative metal compounds which may be used in such reac-
tions include calcium oxide, calcium hydroxide, silver oxide, sil-
ver carbonate, magnesium oxide, magnesium hydroxide, magnesium car-
bonate, magnesium ethoxide, zinc oxide, zinc hydroxide, strontiu~
oxide, strontium hydroxide, cadmium oxide, cadmium hydroxide, cad-
mium carbonate, barium oxide, aluminum oxide, aluminum propoxide,
iron carbonate, copper hydroxide, lead oxide, tin butoxide, cobalt
oxide~ nickel hydroxide, manganese oxide, and the like.
In some cases, incorporation of certain ingredients such as
small amounts of metal acetate or acetic acid in conjunction with
the metal reactant will facilitate the reaction and provide an im-
proved product. For example, use of up to about 5% of zinc acetate
in combination with the required amount of zinc oxide tends to fa-
cilitate the formation of zinc dihydrocarbyl dithiophosphates.
Examples of useful metal salts of dihydrocarbyl dithiophos-
phoric acids, and methods for preparing such salts are found in the
prior art such as for example, U.S. Pat. Nos. 4,263,150; 4,283,635;
4,308,154; 4,322,479; 4,417,990; 4,46~ 5; 4,904,4~1; 4,938,881;
4,941,984; 4,952,328; 4,957,649; and 4,981,602. All disclosures of
each of the foregoing patents pertaining to the makeup and/or syn-
thesis and/or post-treatment of metal salts of dihydrocarbyl phos-
phorodithioic acids (also known as metal salts of dihydrocarbyl di-
thiophosphoric acids) are incorporated herein by reference.
15 -
2~g~1~9
EI-6457
Generally speaking, the preferred types of metal salts of di-
hydrocarbyl dithiophosphoric acids are the oil-soluble metal salts
of dialkyl dithiophosphoric acids. Such compounds generally con-
tain alkyl groups having at least three carbon atoms, and prefer-
ably the alkyl groups contain up to 10 carbon atoms although as
noted above, even higher molecular weight alkyl groups are antirely
feasible. A few illustrative zinc dialkyl dithiophosphates include
zinc diisopropyl dithiophosphate, zinc dibutyl dithiophosphate,
zinc diisobutyl dithiophosphate, zinc di-sec-butyl dithiophosphate,
the zinc dipentyl dithiophosphates, the zinc dihexyl dithiophos-
phates, the zinc diheptyl dithiophosphates, the zinc dioctyl dithi-
ophosphates, the zinc dinonyl dithiophosphates, the zinc didecyl
dithiophosphates, and the higher homologs thereof. Mixtures of two
or more such metal compounds are often preferred for use such as
metal salts of dithiophosphoric acids formed from mixtures of iso-
propyl alcohol and secondary butyl alcohol; isopropyl alcohol, iso-
butyl alcohol, and 2-ethylhexyl alcohol; isopropyl alcoAol, butyl
alcohol, and pentyl alcohol; isobutyl alcohol and octyl alcohol;
and the like.
As noted hereinabove, it is particularly preferred to employ
an ovexbased zinc dihydrocarbyl dithiophosphate, especially a zinc
dialkyl dithiophosphate wherein the alkyl groups are primary alkyl
groups, containing from 6 to 10 carbon atoms each, especially 8
carbon atoms each, and wherein the overbased to neutral ratio is
0.96 or above as determined by 31p nmr. In this connection, over-
based species appear in the range o~ about 103 to about 105 ppm
wherQas neutral species appear in the range of about 100 to about
102 ppm and the signals are integrated in the usual manner to cal-
culate the overba~ed : neutral ratio. Additionally the impurity
content in the zinc dihydrocarbyl dithiophosphate should be very
low. Preferably at 80 ppm, the 31p nmr should provide an integrated
spectrum showing less than 0.25 area percent phosphorus, and at 5
to 15 ppm, the integrated 31p nmr spe~trum should show virtually no
phosphate impurities. LiXewise virtually no impurities should ap-
pear at 95 to 98 ppm in the integrated spectrum. It is also pre-
ferable to use zinc dihydrocarbyl dithiophosphates which exhibit a
copper weight loss in the ~STM D~619 procedure of 0.70 maximum.
Zinc di-(2-ethylhexyldithiophosphata) meating the above criteria is
especially preferred.
(b~ Antiox1dants
The composition~ of this invention preferably contain one or
more antioxidants in order to protect the composition from prema-
ture degradation in the presence of air, especiall~ at e]evated
- 16 -
2~8~
EI-6457
temperatures. Typical antioxidants include hindered phenolic anti-
oxidants, secondary aromatic amine antioxidants, oil-soluble copper
compounds, phosphorus-containing antioxidants, and the like.
Illustrative sterically hindered phenolic antioxidants include
s ortho-alkylated phenolic compounds such as 2,6-di-tert-butylphenol,
4-methyl-2,6-di-tert-butylphenol, 2,4,6-tri-tert-butylphenol, 2-
tert-butylphenol, 2,6-diisoproFylphenol, 2-methyl-6-tert-butylphe-
nol,2,4-dimethyl-6~tert-butylphenol, 4-(N,N-dimethylaminomethyl)-
2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 2-methyl-
6-styrylphenol, 2,6-di-styryl-4-nonylphenol, and their analogs and
homologs. Mixtures of two or more such mononuclear phenolic com-
pounds are also suitable.
Also useful in the compositions of this invention are methy-
lene-bridged alkylphenols, and these can be used singly or in com-
binations with each other, or in combinations with sterically-hin--
dered unbridged phenolic compounds. Illustrative methylene bridged
compounds include 4,4'-methylenebis(6-tert-butyl-o-cresol), 4,4'-
methylenebis(2-tert-amyl-o-cresol), 2,2'-methylenebis(4-methyl-
-6-tert-butylphenol), 4,4'-methylenebis(2,6-di-tert-butylphanol),
and similar compounds. Also useful are mixtures of methylene--
bridged alkylphenols such as are described in U.S. Pat. No.
3,211,652, all disclosure of which is incorporated herein by
reference.
Amine antioxidants, especially oil-soluble aromatic secondary
amines can also be used in the compositions of this invention. Al-
though aromatic secondary monoamines are preferred, aromatic secon-
dary polyamines are also suitable. Illustrative aromatic secondary
monoamines include diphenylamine, alkyl diphenylamines containing
1 or 2 alkyl substituents each having up to about 16 carbon at~ms,
ph~nyl-~-naphthylamine, phenyl-~-naphthylamine, alkyl- or aralkyl-
substituted phenyl-~-naphthvla.-,ine containing one or two alkyl or
aralkyl groups each having up to about 15 carbon atoms, alkyl- or
aralkyl-substituted phenyl-~-naphthylamine containing one or two
alkyl or aralkyl groups each having up to about 16 carbon atoms,
and similar compounds.
- 17 -
2 ~ 9 ~
EI-5457
A preferred type of aromatic amine antioxidant is an alkylated
diphenylamine of the general formula
~ H - -
~,
wherein R1 is an alkyl group (preferably a branched alkyl group)
having 8 to 12 carbon atoms, (more preferably 8 or 9 carbon atoms)
and Rz is a hydrogen atom or an alkyl group (preferably a branched
alkyl group) having 8 to 12 carbon atoms, (more preferably 8 or 9
carbon atoms). Most preferably, R1 and R2 are the same. One such
preferred compound is available commercially as Naugalube 438L, a
material which i5 understood to be predominately a 4,4'-dinonyldi-
phenylamine (i.e., bis(4-nonylphenyl)amine) wherein the nonyl
groups are branched.
Another type of antioxidant that may be included in the compo-
sitions of this invention is comprised to one or more liquid, par-
tially sulfurized phenolic compounds such as are prepared by reac-
ting sulfur monochloride with a liquid mixture of phenols -- at
least about 50 weight percent of which mixture of phenols is com-
posed of one or more reactive, hindered phenols -- in proportions
to provide from about 0.3 to about 0.7 gram atoms of sulfur mono-
chloride per mole of reactive, hindered phenol so as to produce a
liquid product. Typical phenol mixtures useful in making such
liquid product compositions include a mixture containing by weight
about 75~ of 2,6-di-tert-butylphenol, about 10% of 2-tert-butyl-
phenol, about 13% of 2,4,6-tri-tert-butylphenol, and about 2% of
2,4-di-tert-butylphenol. The reaction is exothermic and thus is
preferably kept within the range of about 15C to about 70C, most
preferably between about 40C to about 60C.
If a sulfur~containing antioxidant is to be used, care should
be taken to select one o~ composition and purity that does not
denegrate the copper corrosion resistance imparted to the composi-
tion by the practice of this invention, and to use the antioxidant
at a sufficiently low concentration to insure that such denegration
does not occur.
Mixtures of different antioxidants can also be used. One
suitable mixture is comprised of a combination of (i) an oil-solu-
ble mixture of at least three different sterically-hindered ter~
tiary butylated monohydric phenols which is in the liquid state at
25C, (ii) an oil-soluble mixture of at least three different ste-
rically-hindered tertiary hutylated methylene-bridged polyphenols,
2~8~19~
EI-6457
and (iii) at least one bis(4-alkylphenyl)amine wherein the alkyl
group is a branched alkyl group having 8 to 12 carbon atoms, th~
proportions of (i), (ii) and (iii) on a weight basis falling in the
range of 3.5 to 5.0 parts of component (i) and 0.9 to 1.2 parts of
component (ii) per part by weight of component (iii).
As noted above, it is preferred to use a combination of (1) a
hindered phenolic antioxidant s~ch as a mixture of tertiary butyl
phenols containing at least about 75% and preferably at least about
85% 2,6-di-tert-butylphenol, such as Ethyl~ 735 antioxidant, and
(2) a secondary aromatic amine antioxidant such as alkylated diphe-
nylamines wherein one and more preferably both of the phenyl groups
are substituted by a branched alkyl group containing 6 to 12 and
most preferably about 8 to 10 carbon atoms, such as Naugalube 438L.
(c) Rust Inhibitors
Various types of rust inhibitors are suitable for use in the
compositions of this invention. These include dimer and trimer
acids, such as are produced from tall oil fatty acids, oleic acid,
linoleic acid, or the li~e. Products of this type are currently
available from various commercial sources, such as, for example,
the dimer and trimer acids sold under the HYSTRENE trademark by the
Humco Chemical Division of Witco Chemical Corporation and under the
EMPOL trademark by Emery Chemicals. Another useful type of rust
inhibitor for usa in the practice of this invention are the alkenyl
suc~inic acid and alkenyl succinic anhydride corrosion inhibitors
such as, for example, tetrapropenylsuccinic acid, tetrapropenylsuc-
cinic anhydride, tetradecenylsuccinic acid, tetradecenylsuccinic
anhydride, hexadecenylsuccinic acid, hexadecenylsuccinic anhydride,
and the like. Also useful are the half esters of alkenyl succinic
acids having 8 to 24 carbon atoms in the alkenyl group with alco-
hols such as the polyglycols. Other suitable coxrosion inhibitors
include ether amines; acid phosphates; amines; polyethoxylated com-
pounds such as ethoxylated amines, ethoxylated phenols, and ethox-
ylated alcohols; imidazolines; and the like. Materials of thes2
types are well known to those skilled in the ar~ and a number of
such materials are available as articles of commerce.
Also useful as rus~ inhibitors are aminosuccinic acids or
derivatives thereof represented by the formula:
-- 19 --
20~19~ EI-6457
R6 o
R '-- C -- C -- O R
R i ~ R
R2 o
wherein each of R1, RZ, R5, R6 and R7 is, independently, a hydrogen
atom or a hydrocarbyl group containing 1 to 30 carbon atoms, and
wherein each of R3 and R4 is, independently, a hydrogen atom, a
hydrocarbyl group containing 1 to 30 carbon atoms, or an acyl group
containing from 1 to 30 carbon atoms. The groups R1, R2, R3, R4, R5,
R6 and ~7, when in the form of hydrocarbyl groups, can be, for ex-
ample, alkyl, cycloalkyl or aromatic containing groups. Preferably
R1 and R5 are the same or different straight-chain or branched-chain
hydrocarbon radicals containing 1-20 carbon atoms. Most prefera-
bly, R1 and R5 are saturated hydrocarbon radicals containing 3-6
carbon atoms. ~2, either R3 or R4, R6 and R7, when in the form of
hydrocarbyl groups, are preferahly the same or different straight-
chain or branched-chain saturated hydrocarbon radicals. Preferably
a dialkyl ester of an aminosuccinic acid is used in which R1 and R5
are the same or different alkyl groups containing 3-6 carbon atoms,
R2 i~ a hydro~en atom, and either R3 or ~4 is an alkyl group con-
taining 15-20 carhon atoms or an acyl group which is derived from
a saturated or unsaturated carboxylic acid containing 2-10 carbon
atoms.
:20 Most preferred of the aminosuccinic acid derivatives is a di~
alkylester of an aminosuccinic acid of the above formula wherein R1
and R5 are isobutyl, R2 is a hydrogen atom, R3 is octadecyl and/or
octadecenyl and R4 is 3-carboxy-1-oxo-2-propenyl. In such ester R6
and R7 are most preferably hydrogen atoms.
(d~ Demulsifiers
Typical additives which may be employed as demulsifiers in-
clude alkyl benzene sulphonates, polyethylene oxides, polypropylene
oxides, block copolymers of ethylene oxide and propylene oxida,
salts and esters or oil soluble acids, and the like.
Thus, for example use can be made of oxyalkylated trimethylol
alkanes with molecular weights in the range o~ 1,000 to lOtO00, and
preferably in the range of 3,000 to 8,000. Preferably, the oxyal-
kylated trimethylol alkane is an oxyalkylated trimethylol ethane or
prspane, especially where the oxyalkylene groups are composed o~ a
- 20 -
2~8~19~
EI-6457
mixture of propyleneoxy and ethylenoxy groups and ~here these
groups are so disposed as to form relatively hydrophobic blocks
adjacent the trimethylol group and relatively hydrophilic blocks
remote the trimethylol group. Typical oxyalkylated trimethylol
propane demulsifiers are described ln U.S. Pat. No. 3,101,374.
Commercially available products of this type are available from
BASF Corporation under the Pluradot trademark. They are available
in various molecular weights. Pluradot HA-510 has an average
molecular weight of 4,600 and Pluradot HA-530 has an average
molecular weight of about 5,300. Pluradot additives are propoxy-
lated and ethoxylated trimethylol propanes.
Another type of suitable demulsifers are oxyalkylated alkyl
phenol-formaldehyde condensation products. Typically, these pro-
ducts have molecular weights in the range of about 4,000 to about
6,000 and are comprised of lower alkyl substituted phenol moie~ies
joined together by methylene groups and in which the hydroxyl
groups of the phenolic moieties have been ethoxylated. One such
commercial produ~t is marketed by Ceca S.A. of Paris, France under
the "Prochinor GR77" trade name. The product is supplied as a
concentrate in an aromatic solvent and the active ingredient is
believed to be an ethoxylated nonylphenol-formaldehyde condensate
of molecular weight 4,200 (by gel permeation chromatography cali-
brated with polystyrene~.
Another suitable type of demulsifier is comprised of the te-
tra-polyoxyalkylene derivatives of ethylene diamine, especially the
tetra-poly(oxyethylene)-poly(oxypropylene) derivatives of ethylene
diamine. Materials of this type are available commercially from
BASF Corporation under the "Tetronics" trademark. Materials of
this general type are described in U.S. Pat. NoO 2,979,52~.
Mixtures of alkylaryl sulphonates, polyoxyalkylene glycols and
oxyalkylated alkylphenolic resins, such as are available commer-
cially from Petrolite Corporation under the TOLAD trademark, are
also suitable. One such proprietary product, identified as TOLAD
286K, is understood to be a mixture of these components dissolved
in a solvent composed of alkyl benzenes. TOLAD 286 is believed to
be a similar product wherein the solvent is composed of a mixture
of heavy aromatic naphtha and isopropyl alcohol.
Preferred demulsifiers are proprietary materials available
from BASF Corporation under the Pluronic trademark. These are
block copolymers of propylene oxide and ethylene oxide.
~ 21 -
20 8~ 199 EI-6457
Base Oils.
This invention is applicable to base oils containing at least
50%, preferably at least 70%, more preferably at least 80%, still
more preferably at least 90%, and most preferably 100% by volume of
mineral oil that has an inherent sulfur content of at least 0.2% by
weight. Thus this invention can be applied to base oils or base
oil blends composed entirely of mineral oils having this high inhe-
rent sulfur content. Alternat~vely, this invention can be applied
to blends in which at least 50% of the blend is composed of mineral
oil (which may itself be a blend of two or more mineral oils) ha-
vinq such high inherent sulfur content and the balance is composed
of one or more synthetic or natural oils of lu~rication viscosity.
The mineral oils not only can be hydrocarbon oils of lubri-
cating viscosity derived from petroleum, but can be derived from
1~ tar sands, coal, shale, etc.
Suitable mineral oils include those of appropriate viscosity
refined from crude oil of any source including Gulf Coast, Midcon-
tinent, Pennsylvania, California, Alaska, Mexico, South ~merica,
Africa, Middle East, North Sea and the like. Standard refinery
operations may be used in processing the mineral oil. Among the
general types of petroleum oils useful in the compositions of this
invention are solvent nautrals, bright stocks, cylinder stocks,
residual oils, hydrocracked base stocks, paraffin oils including
pale oils, and solvent extracted naphthenic oils. Such oils and
2S blends of them are produced by a number of conventional techniques
which are widely known by those skilled in the art.
The base oil may be composed of a blend of one or more mineral
oils with a high inherent sulfur content and one or more mineral
oils with a low inherent sulfur content (if any), provided the re-
sultant blend has a sulfur content of at least 0.2% by weight.
As is noted above, the base oil can be a blend which includes
up to 50% by volume of one or more synthetic oils and/or one or
more natural oils.
The synthetic oils comprise a variety of materials such as hy-
drogenated polyolefin oils; poly-~ olefins (e.g., hydrogenated or
unhydrogenated ~ olefin oligomers such as hydrogenated poly-l-de-
cene); alkyl esters of dicarboxylic acids; complex esters of di-
carboxylic acid, polyglycol and alcohol; alkyl esters of carbonic
or phosphoric acids; polysilicones; ~uorohydrocarbon oils; homo-
~2 -
~8~
EI-6457
and inter rpolym~rs of C2-C12 olefins; polyethers; polyglycols; sili-
cates: alkylated aromatics; carbonates; thiocarbonates; orthofor-
mates; borates; and halogenated hydrocarbons; among others.
Representative of such oils are homo- and interpolymers of C2-
C12 monoolefinic hydroc~rbons, alkylated benzenes (e.g., dodecyl
benzenes, didodecyl benzenes, tetradecyl benzenes, dinonyl ben-
zenes, di-(2-ethylhexyl)benzen~s, wax-alkylated naphthalenes); and
polyphenyls (e.g., biphenyls and terphenyls).
Alkylene oxide polymers and interpolymers and derivatives
thereof where the terminal hydroxyl groups have been modified by
esterification, etherification, etc., constitute another class of
synthetic oils which may be included in the blends with the high
sulfur mineral oils. The alkylene oxide derived oils include those
prepared through polymerization of alkylene oxides such as ethylene
oxide or propylene oxide, and the alkyl and aryl ethers of these-
polyoxyalkylene polymers (e.g., methyl polyisopropylene glycol
ether having an average molecular weight of 1,000, diphenyl ether
of polyethylene glycol ha~ing a molecular weight o~ 500-l,000, di-
ethyl ether of polypropylene glycol having a molecular weight of
1,000-1,500) or mono- and poly-carboxylic esters thereof, for ex--
ample, the acetic acid ester, mixed C3-C6 fatty acid esters, or the
Cl3 Oxo acid diester of tetraethylene glycol.
Another type of synthetic oils which may be used with the high
sulfur mineral oils comprises the esters of dicarboxylic acids
(e.g~, phthalic acid, succinic acid, maleic acid, azelaic cid,
suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic
acid dimer) with a variety of alcohols (e.g., butyl alcohol, hexyl
alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol).
Specific examples of these esters include dibutyl adipate, di(2-
ethylhexyl) adipate, didodecyl adipate, di(tridecyl) adipate, di(2-
ethylhexyl) s~bacate, dilauryl sebacate, di~n-hexyl fumarate,
dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl
phthalate, didecyl phthalate, di(eicosyl) sebacate, the 2-ethyl-
hexyl diester of linoleic acid dimer, and the complex ester formed
by reacting one mole of sebacic acid with two moles of tetraethy-
lene glycol and two moles of 2-ethylhexanoic acid.
Esters which may be used as synthetic oils also include those
made from C3-C18 monocarboxylic acids and polyols and polyol ethers
such as neopentyl glycol, trimethylolpropane, pentaerythritol and
dipentaerythritol. Trimethylol propane tripelargonate and penta-
erythritol tetracaproate, the ester formed from trimethylolpropane,
2 ~
EI-6457
caprylic acid and sebacic acid, and the polyesters derived from a
C4-C~4 dicarboxylic acid and one or more aliphatic dihydric C3-C~2
alcohols such as derived from azelaic acid or sebacic acid and
2,2,4-trimethyl-1,6-hexanediol serve as examples.
Silicon-based oils such as the polyalkyl-, polyaryl-, polyal-
koxy-, or polyaryloxy-siloxane oils and silicate oils comprise
another class of synthetic lu~ricants (e.g., tetraethyl silicate,
tetraisopropyl silicate, tetra-(2-ethylhexyl) silicate, tetra-(p-
tert-butylphenyl) silicate, pnly(methyl)siloxanes, and poly(m~thyl-
phenyl)siloxanes~ Other synthetic lubricating oils include liquid
phosphata esters, e.g., tricresyl phosphate and trioctyl phosphate.
Also use.ful as base oils components are hydrogenated or unhy-
drogenated liquid oligomers of C6-C16 alpha-olefins, such as hydro-
genated or unhydrogenated oligomers formed from l-decene. Methods
for the production of such liquid oligomeric l-alkene hydrocarbons
are known and reported in the literature. See for example U.S.
Pat. Nos. 3,749,560; 3,763,244; 3,780,128; 4,172,855; 4,218,330;
4,902,~46; 4,906,798; 4,910,355: 4,911,758; 4,935,570: 4,9~0,822;
4,956,513; and 4,981,578, the disclosures of which are incorporated
herein by reference. Additionallyl hydrogenated 1-alkene oligomers
of this type are available as articles of commerce, for example,
under the trade designations ETHYLFLO 162, ETHYLFLO 164, ETHYLFLO
166, ETHYLFLO 168, ETHYLFLO 170, ETHYLFLO 174, and ETHYLFLO 180
poly-~-olefin oils (Ethyl Corporation; Ethyl Canada Ltd.; Ethyl
S.A.). Blends of such materials can also be used in order to
adjust the viscometrics of the given base oil. Suitable 1-alkene
oligomers are also available from other s~lppliers. As is well
known, hydrogenated oligomers of this type contain little, if any,
residual ethylenic unsaturation.
Preferred oligomers are formed by use of a Friedel-Crafts
catalyst (especially boron trifluoride promoted with water or a Cl20
alkanol) followed by catalytic hydrogenation of the oligomer so
formed using procedures such as are described in the foregoing U.S.
patents.
Other catalyst systems which can be used to form oligomers of
1-alkene hydrocarbons, which, on hydrogenation, provide suitable
oleaginous liquids include Ziegler catalysts such as ethyl aluminum
sesquichloride with titanium tetrachloride, aluminum alkyl cata-
lysts, chromium oxide catalysts on silica or alumina supports and
a system in which a boron trifluoride catalyzed oligomerization is
followed by treatment with an organic peroxide.
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2~8~9
EI-6457
Typical natural oils that may be used as components of the
base oils include castor oil, olive oil, peanut oil, rapeseed oil,
corn oil, sesame oil, cottonseed oil, soybean oil, sunflower oil,
safflower oil, hemp oil, linseed oil, tung oil, oiticica oil, jojo-
ba oil, and the like. Such oils may be partially or fully hydro-
genated, if desired, provided of course that they retain the de-
sired physical properties.
Thus mixtures of hi~h sulfur mineral oils with natural and/or
synthetic oils can be used provided at least 50~ by volumP of the
mixture is mineral oil with an inherent sulfur content of at least
0.2% by weight. The term "base oil" for this disclosure includes
all the foregoing. In all cases, the base oils are only those
which, when a neutral phosphite ester is included therein in accor-
dance with this invention, yield a composition which achieves in
the Cincinnati Milacron Thermal Test procedure, the copper rod
rating improvements referred to hereinabove and in the claims
hereof.
The lubrica$ing oil com~ositions of this invention can thus be
used in a variety of applications such as automotive crankcasa lu-
bricating oils, automatic transmission fluids, gear oils, hydraulic
oils, cutting oils, etc. The preferred application is as power
transmission fluids, espe~ially hydraulic oils.
The fact that the base oils used in the compositions of this
invention may be composed of (i) one or more high sulfur mineral
oils, (ii) a blend of one or more low sulfur mineral oils with one
or more high sulfur mineral oils, (iii) a blend of (i) with one or
more synthetic oils, (iv) a blend of (ii) with one or more synthe-
tic oils, (v) a blend of (i) with one or more natural oils, (vi) a
blend of (ii) with one or more natural oils, (vii) a blend of (i)
with one or more synthetic oils and one or more natural oils or
(viii) a blend of (ii) with one or more synthetic oils and one or
more natural oils does not mean that these various types of oils
are necessarily equivalents of each other. Certain types of base
oils may be used in certain compositions for the specific proper-
ties they possess such as high temperature stability, good low tem-
perature viscometric properties, inertness toward elastomers, etc.
In other compositions, other types of basa oils may be preferred
ror reasons of availability or low cost. Thus, the skilled artisan
will recognize that while the various types of base oils discussed
above may be used in the compositions of this invention, they are
not necessarily functional equivalents of each other in every in-
stance.
~ 25 -
2 0 ~
EI-6457
Pro~ortions and Concentrations
In general, the additives are employed in the base oils in
minor amounts sufficient to improve the performance characteristics
and properties of the base oil or fluid. The amounts will thus
vary in accordance with such factors as the viscosity characteris-
tics of the base oil or fluid employed, the viscosity characteris-
tics desired in the finished product, the service conditions for
which the finished product is-intended, and the performance char-
acteristics desired in the finished product. However, generally
speaking, the following concentrations (weight percent) of the
components (active ingredients) in the base oils or fluids are
illustrative:
MoreParticularly
GeneralPreferredPreferredPreferred
RanqeRanqe _ Ranq~ Ranqe _
Component a) 0.1 - 5 0.2 - 2 0.3 - 1.4 0.35 - 0.8
Component b)0.01 - 2 0.1 - 1.5 0.15 - 1.2 0.2 - 1
Component c) 0 - 2 0.01 - 1.5 0.04 - 1.2 0.05 - 1
Component d) 0 - 2 0.001 - 1.50.005 - 1.0 0.01 - 0.5
The additive concentrates of this invention will usually
contain up to 90 per cent by weight and preferably from 5 to 70 per
cent by weight of one or more inert liquid diluents such as light
mineral oil, with the balance being active in~redients such as
those referred to hereinabove.
This invention is susc~ptible to considerable variation in its
practice. Thus this invention is not intended to be limited by the
specific exemplifications set forth hereinabove. Rather, the sub-
ject matter covered is within the spirit and scope of the appended
claims and the permissible equivalents thereof.
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