Note: Descriptions are shown in the official language in which they were submitted.
CA 02236~09 1998-0~-21
WO 97~191~3 PCT/EP96/05113
Two-Cycle Svnthetic Lubricatinq Oil
This invention relates to a lubricant composition useful as a two-
cycle oil. More particularly the invention relates to two~ycle synthetic oil
which complies with certain test sl~"~lards for land equipment, gasoline
fueled, two-cycle engines, such as motorcycle engines, moped engines,
snowmobile engines, lawn mower engines and the like. Two-stroke-cycle
gasoline engines now range from small, less than 50 cc engines, to higher
performance engines of 200 to 500 cc. The development of such high
performance engines has created the need for new two-cycle oil standards
1:~ and test procedures. The present composition exhibits improved
detergency and smoke reduction characteristics.
Two-cycle engines are lubricated by mixing the fuel and lubricant
and allowing the mixed composition to pass through the engine. Various
types of two-cycle oils, compatible with fuel, have been described in the art.
Typically, such oils contain a variety of additive components in order for the
oil to pass industry standard tests to permit use in two-cycle engines.
Canadian Patent 1,238,448 (1988) discloses the copolymers of
2:5 alpha olefins with dicarboxylic esters which are used as one component of
the composition of the present invention.
US-A4,994,196 (1991) discloses two-cycle engine oils comprising
the same alpha olefin dicarboxylic ester copolymers in combination with
3~ esters of pentaerythritol and calcium phenate.
US-A-5,378,249 (1995) discloses biodegradable two-cycle engine oil
compositions which comprise 20-80% of a heavy ester having a viscosity of
at least 7 cSt at 100~ in combination with 10-85 weight percent of a light
ester oil having a viscosity less than 6.0 cSt at 100~.
US-A-5,171,461 (1992) discloses lubricating compositions
containing a combination of a sulfur compound with an oil soluble or
dispersable source of copper to provide lubricating oils which exhibit
40 improved anti-oxidant and extreme pressure properties.
CONFIP/M~ION COPY
CA 02236~09 1998-0~-21
95A02l0 - 2 -
US-A-4,6~14,822 (1987) discloses metal containing lubricant compositions
which contain copper overbased materials which act as a
dispersanVdetergent and an oxidation and corrosion inhibitor.
US-A-4,8~37,890 discloses lubricating oil compositions containing very small
proportions, that is, 5-500 parts per million of copper as an antioxidant.
EP-A-0 572 273 discloses lubricating oil compositions for two-stroke engines
comprising 30 to 70% of a polyol ester, 30 to 70% of a diester and 1 to 5% of
a polybutene of molecular weight 500 to 2500 and/or 1 to 5% of a
polymethylmethacrylate of molecular weight 5,000 to 40,000 and 5 to .25% of
a dispersant. The compositions have good bio-degradability.
GB-A-2 248 068 discloses an additive for reducing smoke and particulate
emissions during combustion of a fuel oil, particularly a diesel oil, comprisingan alkali metal compound, a compound of a metal of Group 2a of the
Periodic Table and a compound of a transition metal selected from Groups
1 b, 3b, 4b, 5b, 6b, 7b and 8 of the Periodic Table.
The present invention is based on the discovery that the use of oil soluble
copper carboxylate in synthetic ester based two-cycle oil formulations
provides lubricants which exhibit improvements in smoke generation and
detergency, as measured by two-cycle engine tests.
Accordingly, there has been discovered a two-cycle lubricating oil
composition comprising:
a) 10-20% by weight of a first synthetic ester basestock oil being a
copolymer of an alpha-olefin with an ester of a dicarboxylic acid,
the oil having a viscosity of 20 to 50 mm2/s (sSt) at 100~C;
b) 18-30% by weight of a second synthetic ester basestock oil being
an oxo alcohol ester of a dicarboxylic acid, the oil having a
viscosity of 3 to 10 mm2/s (cSt) at 100~C;
AMEN~ ,r-t _~ I
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CA 02236S09 1998-OS-21
95A020 - 2a -
c) 30 to 40% by weight of a polybutene polymer being a polybutene,
polyisobutylene or a mixture of polybutenes and polyisobutylenes
having a number average molecular weight of about 300 to 1500;
d) 15 to 25% by weight of a normally liquid solvent having a boiling
point of up to 300~C;
e) 0.2 to 2% by weight of an oil soluble copper compound; and
. _ . . . ~ . . .. . .
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CA 02236509 1998-05-21
f) 0-~% by weight of lubricating oil additives other than a
polybutene.
This invention also comprises the use of the foregoing oil in a two-
S cycle engine.
The first synthetic ester component is known in the art and is a
copolymer of an alpha olefin with a dicarboxylic acid ester. Such fluid
copolymers are typically prepared from alpha olefins having 3 to 20 carbon
10 atoms, more preferably 6 to 18 carbon atoms, such as propylene, 1-~utene,
1-pentene, 1-hexene, 1-heptene, 1-octene and the like. Examples of
suitable dicarboxylic acids for preparing such materials include maleic acid,
fumaric acid, citraconic acid, mesaconic acid and itaconic acid. The
alcohol is pre~rably one having 1 to 20 carbon atoms, more preferably 3 to
15 8 carbon atoms such as methanol, ethanol, propanol, butanol, pentanol,
hexanol, heptanol, octanol, nonanol, decanol, undecanol and the like. This
material is prepared by copolymerizing the above described alpha olefin
with the above described ester of dicarboxylic acid. Preferred is a butanol
ester of an alpha olefin maleic acid polym~,r~having an average molecular
20 weight of ~ebe~1800 and a viscosity of 35~ at 100~C wherein the ratio of
olefinic to maleic acid monomers is about 1 to 1.3 which is sold
commercially as "Ketjenlube 135" by Akzo Chemicals. The preferred
amount of this component is in the composition of the present invention is
15%.
The second synthetic ester component is a basestock oil comprising
an oxo alcohol ester of a dicarboxylic acid. Suitable oxo alcohols comprise
those having ~boul1 8 to 20 carbon atoms, preferably those having pbou~ 10
to 15 carbon atoms, particularly oxo tridecyl alcohol. Such oxo alcohols are
30 prepared by the process well known in the art which involves the catalytic
reaction of olefins with carbon monoxide and hydroaen at elevated
temperatures of ~ 300 to 400~F and pressures of hb~l~500 to 4000
psigpo form particularly in the presence of cobalt catalyst ald'ehydes having
more than 1 carbon atom than the olefin feedstock, the aldehyde then
3s being hydrogenated to the corresponding alcohol. Illustrative Examples of
suitable dibasic acids which may be employed to synthesize the oxo diester
fluid used in the present invention are oxalic acid, malonic acid, succinic
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acid, glu~taric acid, adipic acid, pomelic acid, suberic acid, azelaic acid and
the like, generally this being i~ 2 to 10 carbon atoms. Particularly
preferreci are adipic acid and alkyl adipic acids such as methyladipic acid
and diethyladipic acid. S~Sh oxo esters synthetic base oils will have a
5 viscosity in the range of 3 to lOl~St)at 100~ for use in the present invention and they are preferably used in an amount of ~19 to 25%. Particularly
preferred is a material sold by Exxon Chemical Comp~ny as 'Vistone A-30",
an oxo tridecyl alcohol adipate having a viscosity of 5.3,KcSt)at 1 00~C.
lOThe polybutene polymer used in this invention is typically a,mixture
of polybutenes, a mixture of poly-n-butenes and polyisobutylene w~iich
normally results from the polymerization of C4 olefins and will have a
number average molecular weight of labou~ 300 to 1500 with a
polyisobutylene or polybutene having a number average molecular weight
15of ~boutl 400 to 1300 being particularly preferred, most preferable is a
mixture of polybutene and polyisobutylene having a number average
molecular weight of ~bou~ 9~0. Number average molecular weight (Mn) is
measured by gel permeation cl~rom~tography. Polymers composed of
100% polyisobutylene or 100% poly~-butene are also within the scope of
20 this invention and within the meaning of the term "a polybutene polymer".
~ preferred polybutene polymer is a mixture of polybutenes and
polyisobutylene prepared from a C4 olefin refinery stream containing pbou~
6 wt~% to 50 wt.% isobutylene with the balance a mixture of butene (cis-
25 and trans-) isobutylene and less than 1 wt%. butadiene. Particularly,
preferred is a polymer prepared from a C4 stream composed of 645 wt.%
isobutylene, 25-35 wt.% saturated butenes and 15-50 wt.% 1- and 2-
butenes. The polymer is prepared by Lewis acid catalysis. Preferably, the
oils of this invention contain pbou~ 35 wt.% polybutene.
'iO
The solvents useful in the present invention may generally be
charac,terized as being normally liquid petroleum or synthetic hydrocarbon
solvents having a boiling point not higher than ~be~ 300~C at atmosphere
pressllre. The preferred amount is ~bou~ 20% by weight. Such a solvent
3~ must also have a flash point in the range of E~ 60-120~C such that the
flash point of the two-cycle oil of this invention is greater than 70~C.
Typical examples include kerosene, hydrotreated kerosene, middle
~ ._ . .
CA 02236~09 1998-0~-21
distillate fuels, isoparaffinic and naphthenic aliphatic hydrocarbon solvents,
dimers, and higher oligomers of propylene butene and similar olefins as
well as paraffinic and aromatic hydrocarbon solvents and mixtures thereof.
Such solvents may contain functional groups other than carbon and
5 hydrogen provided such groups do not adversely affect performance of the
two-cycle oil. Preferred is a naphthenic type hydrocarbon solvent having a
boiling point range of about 91.1~C-113.9~C (196~-237~F) sold as "Exxsol
D80" by Exxon Chemical Company.
The oil soluble copper compound ùseful in the present inve~tion is
present in an amount of from about 0.2% to 2% by weight, with the
preferred amount being 0.5% to 1.5% by weight. A wide variety of oil
soluble copper compounds are useful in the compositions of this invention.
By oil soluble we mean the compound is oil soluble under normal blending
15 conditions in the oil or additive package. Tne copper compound may be in
the cuprous or cupric form. The copper may be in the form of the copper
dihydrocarbyl thio- or dithio-phosphates wherein copper may be substituted
for zinc in the compounds and reactions described above although one
mole of cuprous or cupric oxide may be reacted with one or two moles of
20 the dithiophos,cl~oric acid, respectively. Altematively the copper may be
added as the copper salt of a synthetic or natural carboxylic acid.
Examples include C10 to C18 fatty acids such as stearic or palmitic, but
unsaturated acids such as oleic or branched carboxylic acids such as
napthenic acids of molecular weight from 200 to 500 or synthetic carboxylic
25 acids are preferred because of the improved handling and solubility
properties of the resulting copper carboxylates. Also useful are oil soluble
copper dithiocarbamates of the general formula (RR'NCSS)nCu, where n is
1 or 2 and R and R' are the same or different hydrocarbyl radicals
containing from 1 to 18 and preferably 2 to 12 carbon atoms and including
30 radicals such as alkyl, alkenyl, aryl, aralkyl, alkaryl and cycloaliphatic
radicals. Particularly preferred as R and R' groups are alkyl groups of 2 to
8 carbon atoms. Thus, the radicals may, for example, be ethyl, n-propyl, i-
propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, n-heptyl, n-octyl,
decyl, dodecyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl,
35 methylcyclopentyl, propenyl, butenyl, etc. In order to obtain oil solubility,the total number of carbon atoms (i.e., R and R') will generally be Pboub 5
AMEN~)F:~ Sff~
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CA 02236~09 1998-0~i-21
or greater. Copper sulphonates, phenates, and acetylacetonates may also
be used
Exemplary of useful copper compounds are copper salts of alkenyl
S succinic acids or anhydrides. 1~he salts themselves may be basic, neutral
or acidic. ~hey may be formed by reacting (a) any of the materials above
discussecl ashless dispersants which have at least one free carboxylic acid
(or anhydride) group with (b) a reactive metal compound. Suitable acid (or
anhydride) reactive metal compounds include those such as cuptic or
10 cuprous hydroxides, oxides, acetates, borates, and carbonates or, basic
copper carbonate.
Examples of the metal salts of this invention are Cu salts of
polyisobutenyl succinic anhydride (hereinaffer referred to as Cu-PlBSA),
15 and Cu salts of polyisobutenyl succinic acid. Preferably, the selected metal
employed is its divalent form e.g., Cu+2. The preferred substrates are
polyalkenyl succinic acids in which the alkenyl group has a molecular
weight greater than lobou~ 700. The alkenyl group desirably has a M n from
~ 900 to 1400, and up to 2500, with a Mn ~f Ir~boun~50 being most
20 preferred. Especially preferred is polyisobutylene succinic acid (PIBSA).
These materials may desirably be dissolved in a solvent, such as a mineral
oil, and heated in the presence of a water solution (or slurry) of the metal
bearing material. Heating may take place between 70~ and about 200~C.
Temperatures of 110~ to 1 40~C are entirely adequate. It may be
25 necessary, depending upon the salt produced, not to allow the reaction to
remain at a temperature above ~bout 140~C for an extended period of time,
e.g., lon~er than 5 hours, or decomposition of the salt may occur.
Use of copper salts in the two-cycle oils of this invention allows the
30 oil to meet the industry requirement for exhaust smoke reduction and
detergency without using the conventional relatively higher amounts of
metal detergents, e.g., phenate and polybutene. Such salts are typically
used in the form of concentrated oil solutions, such as solution containing
~obou~40% by weight copper salt in oil. Particularly preferred for use in the
35 oils of this invention are copper oleate, copper linoleate and copper
naphthenate and other copper salts of C10-C1g fatty acids or naphthenic
acids of Mw 200-500.
_, . . .
CA 02236~09 1998-0~-21
The invention further comprises the presence of up to 5% by weight
of one or more special purpose conventional lubricating oil additives, and
these maly be any additive normally included in lubricating oils for a
5 particular purpose.
Additional conventional additives for lubricating oils which may be
present in the composition of this invention include viscosity modifiers,
corrosion inhibitors, oxidation inhibitors, friction modifiers~ dispersants,
10 antifoaming agents, antiwear agents, pour point depressants, dete,rgents,
rust inhibitors and the like.
Typical oil soluble viscosity modifying polymers will generally have
weight average molecular weights of from pbou~ 10,000 to 1,000,000 as
15 determined by gel permeation chromatography.
Corrosion inhibitors are illustrated by phosphosulfurized
hydrocarbons and the products obtained by reacting a phosphosulfurized
hydrocarbon with an alkaline earth metal oxide or hydroxide. "Cobratech
20 356", which is be~ol~icole in propylene glycol, is preferred for use in this
invention in an amount of ~eboull0.03 wt.%.
Oxidation inhibitors are antioxidants exemplified by alkaline
earth metal salts of alkylphenol thioesters having preferably Cs-C12 alkyl
25 side chain such as calcium nonylphenol sulfide, barium t-octylphenol
sulfide, dioctylphenylamine as well as sulfurized or phospho sulfurized
hydrocarbons.
Friction modifiers include fatty acid esters and amides, glycerol
30 esters ol dimerized fatty acids and succinate esters or metal salts thereof.
Dispersants are well known in the lubricating oil field and
include high molecular weight alkyl succinimides being the reaction
products of oil soluble polyisobutylene succinic anhydride with ethylene
3 s amines sucn as tetraethylene pentamine and borated salts thereof.
Preferred for use in this invention is 2.41% of a dispersant comprising a
borated Mn 950 polyisobutenyl succinimide
. , ,
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Pour point depressants also known as lube oil flow improvers
can lower the temperature at which the fluid will flow and typical of these
additives are Cg-C18 dialkyl fumarate vinyl acetate copolymers,
5 polymethacrylates and wax naphthalene.
Foam control can also be provided by an anti-foamant of the
polysiloxane type such as silicone oil and polydimethyl siloxane.
Anti-wear agents reduce wear of metal parts and represe,ntative
materials are zinc dialkyldithiophosphate and zinc diaryl diphosphate.
.
Detergents and metal rust inhibitors include the metal salts of
sulfonic acids, alkylphenols, sulfurized alkylphenols, alkyl salicylates,
15 naphthenates and other oil soluble mono and dicarboxylic acid. Neutral or
highly basic metal salts such as highly basic alkaline earth metal sulfonates
(especially calcium and magnesium salts) are frequently used as such
detergents. Also useful is nonylphenol sulfide. Similar materials made by
reacting an alkylphenol with commercial sulfur dichlorides. Suitable
20 alkylphenol sulfides can also be prepared by reacting alkylphenols with
elemental sulfur. Preferred for use in this invention is 1.5% by weight
nonylphenol sulfide.
Also suitable as detergents are neutral and basic salts of phenols,
25 generally known as phenates wherein the phenol is generally an alkyl
substituted phenolic group, where the substituent is an aliphatic
hydrocarbon group having pboutl4 to 400 carbon atoms. Preferred for use
in the invention is 0.58% by weight calcium phenate.
The lubricating oil compositions of the present invention will mix
freely wïth the fuels used in such two-cycle engines. Admixtures of such
lubricating oils with fuels comprise a further embodiment of this invention.
The fuels useful in two-cycle engines are well known to those skilled in the
art and usually contain a major portion of a normally liquid fuel such as a
3S hydrocarbonaceous petroleum distillate fuel, e.g., motor gasotine is defined
by ASTM specification D439-73. Such fuels can also contain non-
hydrocarbonaceous materials such as alcohols, ethers, organo nitro
CA 02236~09 1998-0~-21
compounds and the like, e.g., methanol, ethanol, diethyl ether, methylethyl
ether, nitro methane and such fuels are within the scope of this invention as
are liquid fuels derived from vegetable and mineral sources such as corn
alpha shale and coal. Examples of such fuel mixtures are combinations of
5 gasoline and ethanol, diesel fuel and ether, gasoline and nitro methane,
etc. Particularly preferred is gasoline, that is, a mixture of hydrocarbons
having an ASTM boiling point of 60~C at the 10% distillation point to pbou4
205~C at the 90% distillation point.
al The lubricants of this invention are used in admixture with f,uels in
amounts of pbou~l 20 to 250 parts by weight of fuel per 1 part by weight of
Iubricating oil, more typically~l30-100 parts by weight of fuel per 1 part
by weight of oil. Such admixtures and their use in two-cycle engines are
further embodiinenls of this invention.
1~;
The invention is further illustrated by the following examples which
are not to be considered as limitative of its scope. Examples 2 and 3 are
for comparison and are not part of this invention. All percentages are by
weight.
Example 1 (EEC 16275A)
lwo oils of the invention \,vere prepared from the following:
(Trademarked components (a), (b), (c) and (i) are identified in the
specification):
2~j
comPollent Oil 1-A Oil 1-B
(a) "Ketjenlube 135" 15.00% 15.00%
(b) "Vistone A-30" 24.25% 1 9.78 %
(c) "Exxsol D-80" 20.00 % 2 5.00 %
(d) Polyisobutylene Mn 950 35.00% 35.00%
(e) (,opperOleate(active ingredient)1.23% 0.7 0 %
(f) Borated Mn 950 polyisobutenyl
succinimide dispersant 2.41% 2.41%
(g) Calcium Phenate 0.58 % 0.58 %
(h) Nonylphenol sulfide 1.50% 1.50%
(i) "Cobratech 35G" 0.03% 0.03%
100% 1 00%
n ~
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WO 97/19153 PCT/EP96/05113
- 10 -
These two oils were evaluated in accordance with the JASO M345
test procedures JASO M340, M341, M342 and M343. This is an engine
5 test estPhlished by society of A~to,noti~e Engineers of Japan (JSAE) for
two~ycle gasoline engine oils. As of July 1,1994, oiis used in two-cycle
engines are being labeled in accor~lance with the JASO-M345 standards as
announced by the Japan Automobile Standards O~ga,~i~ation (JASO).
JASO published the JASO M345 slan.Jards in April,1994. "EGD
10 Detergency" is a reference to a further modification of the normat JASO
M341 detergency test (1 hour) procedure in which the test is run for 3
hours. This is a more stringent ~landa~d expected to be adopted by ISO
(the International Organization for Standardization) as published by
Committee Draft of Ja~nuary 5, 1995 of the Technical Committee 28. "FC" is
15 the highest pei ror",ance standard for the JASO M345 standards.
The engine test results for Oils 1-A and 1-8 are in the Table below.
Oils 1-A and 1-B Enqine Test Results - JASO M345 & ISO-EGD
JASO M345
Oil 1-A 1-B Standard-FC ISO-EGD
Minimum Minimum
EGD Detergency 151/155 126/135 -- 125
JASO DetergencyM341 123 118 95
JASO Smoke M342 182 163 85 85
Example 2 (Comparative Example)
An oil being the same as Example 1 was formulated except it
contained 25.48% of the Vistone A-30 and no copper oleate.
This oil had a value of 137 in the JASO Smoke M342 test, which is
30 significantly less than Oils 1-A and 1-B of this invention.
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WO 97/19153 PCT/EP96/05113
- 11 -
Example 3 (Comparative Example)
Another oil was formulated being the same as Example 1 except that
s it had 24.81% of Vistone A-30, 0.25 wt.% of a calcium sulfonate and no
copper oleate.
This oil had a value of 121 in the EDG Detergency test which is not a
passing ~/alue.
Example 4
Another oil similar to Oil 1-A was prepared which contail,ed 19.25 of
Vistone A-30 and 25% of Exxsol D-50, but otherwise the same.
This oil had a value of 159 in the EDG Detergency test and 183 in
the JASO Smoke M342 test.
Examples 2 and 3 which contained no copper salt, showed inferior
characteristics in terms of both smoke generation and detergency when
measured in two-cycle engines
