Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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C-4271
LUBRICANT COMPOSITION
This invention relates to improved oil for crank-
case service for internal combustion engines. Oils for
such service contain various additives which serve differ-
ent functions. Ashless dispersants are added to preventdeposition of engine sludge. Zinc dihydrocarbyldithio-
phosphate is added to inhibit wear and provide antioxidant
protection. Alkaline earth metal alkylbenzene or petroleum
sulfonates function as high temperature detergents. Over-
based alkaline earth metal sulfonates or salicylatesprovide both detergent action and an alkaline reserve to
protect engine parts against corroslon. Use of certain
surfactants for lubricating oil is discussed in U. S.
3,509,052 and U. S. 3,928,219. These include certain oxy-
alkylated polyols, oxyalkylated ethylenediamine, nonyl-
phenyl polyethylene glycol ethers and the like.
According to the present invention the rust and
corrosion-inhibiting properties of lubricating oil are
significantly improved by addition of the combination of
an oxyalkylated sorbitan tri-fatty acid ester and an oxy-
alkylated alkylphenol, especially an oxyethylated alkyl-
phenol.
A preferred embodiment of the invention is a
lubricating oil composition comprising a major amount of
lubricating oil and a minor corrosion-inhibiting amount of
the combination of (a) an oxyalkylated sorbitan triester
of a fatty acid and (b) an oxyethylated C4-12 alkylphenol.
The oxyalkylated sorbitan triester can be made by
esterifying one mole of sorbitan with about three moles of
fatty acid. Preferred fatty acids contain about 10-20
carbon atoms. Examples of these are decanoic acid, lauric
acid, palmitic acid, stearic acid, arachidic acid, tall
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oil acids and the like. The most preferred fatty acid is
oleic acid or mixtures of fatty acids containing substan-
tial amounts of oleic acid.
Esterification can be conducted by known methods
such as by heating a mixture of sorbitan and fatty acid
to distill out water. A distillation aid such as xylene
can be used. The reaction forms a mixture in which the
principal component is the triester although minor amounts
of di- and tetraester might form. These will not inter-
fere with the effectiveness of the product.
The sorbitan triester is then reacted with analkylene oxide such as ethylene oxide, propylene oxide or
butylene oxide. The alkylene oxide reacts mainly with
the free hydroxyl group on the sorbitan triester to form
an oxyalkylene chain with a terminal hydroxyl group. The
length of the chain can be varied by adjusting the ratio
of alkylene oxide to sorbitan tri-fatty acid ester. Some
of the alkylene oxide can react with the ester bond to
insert oxyalkylene units between the sorbitan and the fatty
acid. Preferably, the reaction is conducted until about
4-50 moles of alkylene oxide are reacted per mole of sor-
bitan tri-fatty acid ester. A preferredrange is about 10-30
moles of alkylene oxidé and a most preferred coadditive is
formed when an average of about 20 moles of alkylene oxide
react per mole of sorbitan tri-fatty acid ester.
The preferred alkylene oxide is ethylene oxide
which forms a chain of repeating ethyleneoxy units.
Suitable oxyalkylated sorbitan tri-fatty acidesters
are available commercially. Atsurf 2822 (registered trade-
mark),a product of ICI United States, Inc., is an oxy-
ethylated sorbitan trioleate containing an average of about
20 ethyleneoxy units per molecule. It is made by esteri-
fying one mole of sorbitan with three moles of oleic acid
followed by reaction with ethylene oxide. It is very
effective in the present combination.
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The other required component in the combination is
an ethoxylated alkylphenol. Preferably, the alkylphenol
contains about 4-12 carbon atoms in the alkyl group. More
prefereably, the alkyl group contains about 7-12 carbon
atoms such as heptylphenol, 2-ethylhexylphenol, decylphenol
and dodecylphenol. The most preferred alkylphenol is nonyl-
phenol.
The coadditive is made by reacting alkylphenol with
ethylene oxide until the desired number of ethylenoxy groups
are reacted. Preferably there are an average of about 2-10
ethyleneoxy groups per each alkylphenol. More prefereably
each alkylphenol has an average ofabout 3-5 ethyleneoxy
groups per molecule. The most preferred additive is an
ethoxylated nonylphenol containing an average of about 4
oxyethylene groups. Such additives are commercially avail-
able. One such additive is marketed by Monsanto Company
under the name "Sterox ND" (registered trademark).
The amount of each additive used need only be an
amount such that the combination provide adequate corrosion
and rust protection in an engine. A useful range is about
0.005-0.3 weight percent of the oxyalkylated sorbitan tri-
ester and 0.01-0.5 weight percent of the oxyethylated
alkylphenol.
Coadditives are included in the fully~formulated
crankcase lubricant. Examples of these are dispersants
such as the polyisobutyl succinimide of ethylenepolyamine
and polyisobutylphenol Mannich condensates with formalde-
hyde and ethylenepolyamine. Metal detergents such as calcium
alkylbenzene sulfonate, magnesium petroleum sulfonate,
calcium salicylates and calcium alkyphenate are convention-
ally included.
Of special importance in preventing rust are the
overbased metal detergents. These include overbased alka-
line earth metal alkylbenzene sulfonates, ~etroleum sul-
fonates, phenates, salicylates and the like. Examples ofthese are overbased calcium alkylbenzene sulfonate,
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overbased calcium petroleum sulfonate, overbased magnesium
alkylbenzene sulfonate, overbased calcium salicylate, over-
based calcium alkylphenate, overbased magnesium alkyl-
phenate sulfide and the like. Overbasing methods are well
known. For example, alkylbenzene sulfonic acid having an
equivalent weight of about 300-2,000 can be overbased by
reaction with excess calcium oxide in the presence of water
and methanol followed by carbon dioxide injection. The
colloidal alkaline earth metal base in these additives
serve to neutralize acids in blow-by gases formed in com-
bustion.
Viscosity index improvers are generally added to
improve viscosity property of the formulated oil. These
include the polyalkylmethacrylate type and the olefin co-
polymer type. Examples of the latter are ethylene/propyle~Rcopolymer, styrene/butadiene copolymer and the like.
Phosphosulfurized olefins can be added such as
phosphosulfurized terpenes or phosphosulfurized polybutenes.
These may be further reacted by steam blowing or by neutral-
ization with alkaline earth metal bases such as bariumoxide.
Phenolic antioxidants are frequently added to the
oil compositions. Examples of these are 4,4'-methylenebis-
(2,6-di-tert-butylphenol); 2,6-di-tert-butyl-4-dimethyl-
aminomethylphenol; 4,4'-thiobis-(2,6-di-tert-butylphenol)
and the like
Zinc salts of dihycro-arbyldithiophosphoric acid
are routinely added to provide both wear and antioxidant
protection. A typical example is zinc di-(2-ethylhexyl)-
dithiophosphate.
The following example illustrates the preparation ofa typical formulated oil suitable for use in an engine
crankcase.
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Example 1
In a blending vessel place 1,000 gallons 150 SUS
solvent refined mineral oil. To this add 100 gallons
l-decene oligomer containing mainly trimers and tetramers.
Add sufficient zinc isobutylamylthiophosphate to provide
0.07 weight percent zinc. Add overbased (TBN 300) calcium
alkylbenzene sulfonate in an amount to provide 0.15 weight
percent calcium. Add 30 gallons of a poly-laurylmethacrylate
VI improver. Add sufficient polyisobutyl succinimide of
tetraethylene pentamine to provide 3 weight percent active
dispersant. Add 0.03 weight percent Atsurf 2822 and 0.3
weight percent Sterox ND. Blend the oil until homogenous
and package for distribution.
In many cases the additive combination of this in-
vention is first packaged in an additive concentrate formu-
lated for addition to lubricating oil. These concentrates
contain conventional additives such as those listed above
in addition to the oxyalkylated sorbitan triester and
ethoxylated alkylphenol described herein. The various addi-
tives are present in a proper ratio such that when a quantityof the concentrate is added to lubricating oil the various
additives are all present in the proper concentration. The
additive concentrate also contains mineral oil in order to
maintain it in liquid form. The following example illustrates
formulation of an additive concentrate formulated for addi-
tion to lubricating oil to provide an effective crankcase
lubricant
Example 2
In a blending vessel place 1199.5 lbs.of 100 SUS
mineral oil, 784 lbs. of polyisobutyl succinimide of tetra-
ethylene pentamine, 2352 lbs. of ethylene/propylene copoly-
mer VI improver, 264.8 lbs. of zinc di-(2-ethylhexyl)dithio-
phosphate, 245 lbs. of overbased calcium a~lkylbenzene sul-
fonate (300 TBN), 5.88 lbs. of Atsurf 2822~and 58.8 lbs. of
Sterox ND. Blend until homogenous and then package. The
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addition of 2450 lbs. of the above concentrate to 1,000
gallons of 150 SUS mineral oil will provide an effective
crankcase lubricant.
Standard multi-cylinder Sequence IId tests were
carried out in a fully formulated oil containing a commer-
cial succinimide ashless dispersant, a zinc dialkyldithio-
phosphate, a commercial viscosity index improver, a com-
mercial 300 TBN overbased calcium alkylbenzene sulfonate
and 0.3 weight percent Sterox ND and 0.03 weight percent
Atsurf 2822. In this test a rust rating of 8.5 or above
is a pass. The test was conducted using two different base
oils. Ratings of 8.5 and 8.7 were obtained. Both oils
passed.
