Note: Descriptions are shown in the official language in which they were submitted.
CA 02236~11 1998-0~-21
95A021 - 1 -
Two-Cycle Ester Based Synthetic Lubricating Oil
(PT-1042)
This invention relates to a lubricant composition useful as a two-cycle oil.
More particularly the invention relates to two-cycle synthetic oil which
complies with certain test standards for land equipment, gasoline fuelled,
two-cycle engines, such as motorcycle engines, moped engines, snowmobile
10 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 - _ -
and test procedures. The present composition exhibits improved detergency
and reduced exhaust port blocking 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.
US-A-4,994,196 (1991) discloses two-cycle engine oils comprising alpha
olefin dicarboxylic ester copolymers in combination with 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~.
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.
A.~ N~ T
CA 02236~11 1998-0~-21
95A02 1 - 1 a -
EP-A-0 640 680 discloses two-stroke oil compositions comprising
polybutenes which are very low in, or substantially free of n-butenes in order
to achieve low smoke emission. Synthetic esters may be present but
specific esters are not disclosed.
The present invention is based on the discovery that the use of a blend of
ester basestock oils in two-cycle oil formulations provides lubricants which
exhibit improvements, as measured by two-cycle engine tests, most notably
in exhaust port blocking reduction and detergency.
~; ., . -
CA 02236~11 1998-0~-21
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 an ester of pentaerythritol (technical grade) with a
mixture of Cg branched and C8-C1 o linear
morlocarboxylic acids, the oil having a viscosity of Pbou~
6 to 8,J~st)at 1 00~C;
b) 18-30% by weight of a second synthetic ester base st~ck
oil being an oxo alcohol este~of a dicarboxylic acid, the
oil having a viscosity of 3 to 1 Ol~St)at 1 00~C;
lS 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 ~300 to 1500;
d) 15 to 35% by weight of a normally liquid solvent having a
boiling point of up to 300~C; and c~ ~l~sh po;r~
~ ~ 120~C~ ~d
e) 0-5% by weight of lubricating oil additives other than a
polybutene.
This invention also comprises the use of the foregoing oil in a two-
cycle engine.
The first synthetic ester base oil is known in the art and is the ester
of technical grade pentaerythritol with a mixture of (a) C8 branched
monocarboxylic acids and (b) linear mixed C8 and C10 monocarboxylic
acids. Technical grade pentaerythritol contains labout 86-90% by weight
monopentaerythritol, 7-12% dipentaerythritol and 1-2% tripentaerythritol.
The acids comprise ~ 45-55 mol% of branched C8 acids, preferably 45
mol%, and 5545 mol% of a mixture of linear C8 and C10 acids, preferably
55 mol%. This acid mixture of linear octanoic and decanoic acids
comprises~boutl48-58 mol% of Cg and 3642 mol% of C10, and very minor
- . -
_
CA 02236~11 1998-0~-21
amounts of nC:6 and nC12 acids, e.g. 3-5 mol% nC6 and 0.5-1 mol% nC12
aci~,are typically-present. The preferred ester oil has a viscosity of ~t
6.8~St)at 100~C and the preferred amount is 15% by weight.
s The second synthetic ester component is a basestock oil comprising
an oxo alcohol ester of a polycarboxylic acid. Suitable oxo alcohols
comprise those having Pbout 8 to 20 carbon atoms, preferably those having
~110 to 1~ carbon atoms, particularly oxo tridecyl alcohol. Such oxo
alcohols are prepared by the process well known in the art which involves
the catalytic reaction of olefins with carbon monoxide and hydrogen at
elevated temperatures of labou~ 300 to 400~F and pressures o~500
to 4000 psig) to form particularly in the presence of cobalt catalyst
aldehydes having more than 1 carbon atom than the olefin feedstock, the
aldehyde then 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 acid, glutaric acid, adipic acid, pomelic acid,
suberic acid, azelaic acid and the like, generally this being ~ t 2 to 10
carbon atoms. Particularly preferred are adipic acid and alkyl adipic acids
such as methyladipic acid and diethyladipic acid. ~,~c~ oxo esters
synthetic base oils will have a viscosity in the range of 3 to 1OJ~cSqat 100~
for use in the present invention and they are preferably used in an amount
of about 19 to 25%. Particularly preferred is a material sold by Exxon
Chemical Company~as ' \listone A-30", an oxo tridecyl alcohol adipate
having a viscosity of 5.3,~;S~at 1 00~C used in an amount of 20.48%.
The polybutene polymer used in this invention is typically a mixture
of polybutenes, a mixture of poly-n-butenes and polyisobutylene which
normally results from the polymerization of C4 olefins and generally will
have a number average molecular weight of le~ 300 to 1500 with a
polyisobutylene or polybutene having a number average molecular weight
of ~ 400 to 1300 being particularly preferred, most preferable is a
mixture of polybutene and polyisobutylene having a number average
molecular weight of about 950. Number average molecular weight (Mn) is
3 5 measured by gel permeation chromatography. Polymers composed of
100% polyisobutylene or 100% poly-n-butene are also within the scope of
this invention and within the meaning of the term "a polybutene polymer".
. .
CA 02236~11 1998-OS-21
A preferred polybutene polymer is a mixture of polybutenes and
polyisobutylene prepared from a C4 olefin refinery stream containing pbo~
6 wt.% to 50 wt.% isobutylene with the balance a mixture of butene (cis-
5 and trans-) isobutylene and less than 1 wt%. butadiene. Particularly,
preferred is a polymer prepared from a C4 stream composed of 645 v~t.%
isobutylene, 25-35 wt.% saturated butenes and 15-~0 v~t.% 1- and 2-
butenes. The polymer is prepared by Lewis acid catalysis. Preferably, the
oils of this invention contain~bout 35 wt.% polybutene.
The solvents useful in the present invention may generally- be
characterized as being normally liquid petroleum or synthetic hydrocarbon
solvents having a boiling point not higher than ~bout 300~C at atmosphere
pressure. The preferred amount is pbou~ 25% by weight. Such a solvent
lS must also have a flash point in the range of about 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
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
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 invention further comprises the presence of up to 5% by weighl:
of one or more special purpose conventional lubricating oil additives, and
these may be any additive normally included in lubricating oils for a
30 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,
35 dispersants, antifoaming agents, antiwear agents, pour point depressants,
detergents, rust inhibitors and the like.
~ ? ~A~EP --
CA 02236~11 1998-0~-21
Typical oil soluble viscosity modifying polymers will generally have
weight average molecular weights of from ~l 10,000 to 1,000,000 as
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
356", which is benzotrizole in propylene glycol, is preferred for use in this
invention in an amount of ~boubO.03 wt.%.
Oxidation inhibitors are antioxidants exemplified by àlkaline
earth metal salts of alkylphenol thioesters having preferably Cs-C12 alkyl
side chain such as calcium nonylphenol sulfide, barium t-octylphenol
sulfide, dioctylphenylamine as well as sulfurized or phospho sulfurized
hydrocarbons. Also included are oil soluble antioxidant copper compounds
such as copper salts Of C10 to C18 oil soluble fatty acids.
Friction modifiers include fatty acid esters and amides, glycerol
esters of dimerized fatty acids and succinate esters or metal salts thereof.
Dispersants are well known in the lubricating oil field and
include high molecùlar weight alkyl succinimides being the reaction
products of oil soluble polyisobutylene succinic anhydride with ethylene
amines such 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.
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,
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 representative
materials are zinc dialkyldithiophosphate and zinc diaryl diphosphate.
-- ~ P ~ FJ ~
CA 02236511 1998-OS-21
Detergents and metal rust inhibitors include the metal salts of
sulfonic acids, alkylphenols, sulfurized alkylphenols, alkyl salicylates,
naphthenates and other oil soluble mono and dicarboxylic acid. Neutral or
S 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
alkylphenol sulfides can also be prepared by reacting alkylphenols with
lO 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,
generally known as phenates, wherein the phenol is generally an alkyl
l S substituted phenolic group, where the substituent is an aliphatic
hydrocarbon group having ~bou~ 4 to 400 carbon atoms. Preferred for use
in the invention is 0.58% by weight calcium phenate.
Also suitable are oil soluble copper carboxylates which may be
20 present in amounts of 0.2 to 2% by weight and are used as antioxidants or
to improve engine performance, examples being copper oleate or copper
naphthenate in amounts of 0.5 to 1.5% by weight.
The lubricating oil compositions of the present invention will mix
25 freely with 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
hydrocarbonaceous petroleum distillate fuel, e.g., motor gasoline is defined
30 by ASTM specification D~39-73. Such fuels can also contain non-
hydrocarbonaceous rnaterials such as alcohols, ethers, organo nitro
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,
3s alpha shale and coal. Examples of such fuel mixtures are combinations o~
gasoline and ethanol, diesel fuel and ether, gasoline and nitro methane,
etc. Particularly preferred is gasoline, that is, a mixture of hydrocarbons
, , ,
CA 02236511 1998-OS-21
having an ASTM boiling point of 60OC at the 10% distillation point to
205~C at the 90% distillation point.
The lubricants of this invention are used in admixture with fuels in
amounts of labe~ 20 to 250 parts by weight of fuel per 1 part by weight of
lubricating oil, more typically~bout~30-100 parts by weight of fuel per 1 part
by weight of oil Such admixtures and their use in two-cycle engines are
further embodiments of this invention.
I0 The invention is further illustrated by the following examples which
are not to be considered as limitative of its scope. Example 2 is for
comparison and is not part of this invention. All percentages are by weight.
Example 1
An oil of the invention was prepared from the following:
(Trademarked components (a), (b), (c) and (h) are identified in the
specification), and '~PE ester" is the preferred ester of technical grade
pentaerythritol with a mixture of 45 mol% linear Cg acid and 55~m~~J0 of a
mixture of n-octanoic and n-decanoic acid having a viscosity of 6.8l~St)at
1 00~C as disclosed in the specification:
Component Oil 1
(a) TPE Ester 15.00%
(b) '~istone A-30" 20.48%
(c) "Exxsol D-80" 25.00%
(d) Polyisobutylene Mn 950 35 00%
(e) Borated Mn 950 polyisobutenyl
succinimide dispersant 2.41%
(f) Calcium Phenate 0.58%
(g) Nonylphenol sulfide 1.50%
(h) "Cobratech 35G" 0 03%
3 ~ 100%
AME~DE~ EET
IPrA/EP
CA 02236511 1998-05-21
This oil was evaluated in accordance with the JASO M345 test
procedures JASO M340, M341, M342 and M343. This is an engine test
established by society of Automoti\fe Engineers of Japan (JSAE) for tNo-
cycle gasoline engine oils. As of July 1, 1994, oils used in two-cycle
s engines are being labeled in accordance with the JASO-M345 standards as
announced by the Japan Automobile Standards Organization (JASO).
JASO published the JASO M345 standards in April, 1994. "EGD
Detergency" is a refe-ence to a further modification of the normal JASO
M341 detergency test (1 hour) procedure in which the test is run for 3
10 hours. This is a more stringent standard expected to be adopted py ISO
(the International Organization for Standardization) as publislied by
Committee Draft of January 5, 1995 of the Technical Committee 28. "FC" is
the highest performance standard for the JASO M345 standards.
Example 2 (Comparative Example~
Oil 2 was the same as Oil 1 of the invention except that "Ketjenlube
135" a synthetic ester being a butanol ester of an alpha-olef~maleic acid
copolymer used which had a Mn of 1800 and a viscosity of 35l~St)at 100~C
20 in place of the TPE Ester.
The engine test results for Oils 1 and 2 are in the Table below:
Enqine Test Results - JASO M345 & ISO-EGD
JASO M345
Oil 1 2Standard-FC ISO-EGD
Minimum Minimum
EGD Detergency 145 122 -- 125
JASO Detergency M341 123 111 95 --
JASO Lubricity M340 101 112 95 95
JASO Torque M340 99 99 98 98
JASO Blocking M343 153 93 90 90
JASO Smoke M342 125 157 85 85
, ~ _,
CA 02236511 1998-05-21
WO 97119154 PCT/EP961051X5
Oil 1 of the invention shows markedly superior results in terms of
detergency and exhaust port blocking while achieving passing values in all
other aspects of the engine tests, when compared with another oil based on
ester blends, Oil 2.
