U.S. patent application number 09/847015 was filed with the patent office on 2003-02-06 for combustion improving additive for small engine lubricating oils.
Invention is credited to Hartley, Rolfe J., Rea, Salvatore, Stover, William H..
Application Number | 20030027727 09/847015 |
Document ID | / |
Family ID | 25299556 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030027727 |
Kind Code |
A1 |
Hartley, Rolfe J. ; et
al. |
February 6, 2003 |
Combustion improving additive for small engine lubricating oils
Abstract
There are disclosed novel reaction products of a borated
hydrocarbyl succinimide dispersant and phosphate or phosphite
compounds which are highly effective combustion improver additives
for use in two-cycle and small engine four-cycle lubricating
oils.
Inventors: |
Hartley, Rolfe J.;
(Cranbury, NJ) ; Rea, Salvatore; (Franklin Square,
NY) ; Stover, William H.; (Sarnia Ontario,
CA) |
Correspondence
Address: |
Infineum USA L.P.
Law Department
1900 East Linden Avenue
P.O. Box 710
Linden
NJ
07036-0710
US
|
Family ID: |
25299556 |
Appl. No.: |
09/847015 |
Filed: |
May 1, 2001 |
Current U.S.
Class: |
508/188 ;
508/591; 548/405 |
Current CPC
Class: |
C10M 2203/1065 20130101;
C10M 2205/0265 20130101; C10M 2223/049 20130101; C10N 2020/01
20200501; C10M 2215/28 20130101; C10M 159/02 20130101; C10N 2030/06
20130101; C10M 2223/04 20130101; C10M 2203/1085 20130101; C10N
2010/04 20130101; C10N 2020/02 20130101; C10N 2030/10 20130101;
C10M 2223/045 20130101; C10N 2060/14 20130101; C10M 2203/1006
20130101; C10M 2223/047 20130101; C10M 169/04 20130101; C10M
2203/106 20130101; C10M 2223/043 20130101; C10N 2020/04 20130101;
C10N 2040/26 20130101 |
Class at
Publication: |
508/188 ;
508/591; 548/405 |
International
Class: |
C10M 143/06; C10M
159/12 |
Claims
What is claimed is:
1. A two-cycle lubricating oil composition having a kinematic
viscosity of at least 6.5 mm.sup.2/s (cSt) at 100.degree. C. which
comprises an admixture of: (a) 3-50 wt. % of a polybutene polymer
having a Mn of about 300-1500; (b) 2-45 wt. % of a normally liquid
aliphatic hydrocarbon solvent having a boiling point of up to
380.degree. C.; (c) 0.1 to 10.0% by weight of a combustion
improving additive being the reaction product of (1) a borated
nitrogen-containing lubricating oil dispersant, and (2) a
phosphorus compound selected from the group consisting of (i) zinc
dialkyldithiophosphates, (ii) acid phosphates of the formula
(RX).sub.2P(:X)XH where R is H or C.sub.3-C.sub.20 hydrocarbyl, at
least one R being hydrocarbyl, and X may be O or S, (iii) amine
salts of the acid phosphates of (ii) wherein the amine is a primary
or secondary C.sub.3-C.sub.20 aliphatic or aromatic amine, and (iv)
phosphites of the formula P(OX').sub.3 wherein X' is H or
hydrocarbyl, at least one X' being a hydrocarbyl, the hydrocarbyl
being a C.sub.1-C.sub.20 aliphatic, aromatic or alkyl aromatic
hydrocarbyl group. (d) 20 to 94.9% by weight of a mineral or
synthetic oil of lubricating viscosity; and (e) 0 to 20% by weight
of an additive package for two cycle lubricating oil additives,
such additives being present in an amount to provide their normal
attendant functions and enable the two-cycle lubricating oil
composition to satisfy the industry standards for two cycle
lubricating oil compositions.
2. The composition of claim 1 wherein the combustion improving
additive is the reaction product of a borated polyisobutenyl (Mn
450-2,500) succinimide dispersant.
3. The composition of claim 1 wherein the combustion improving
additive is the reaction product of a zinc
dialkyldithiophosphate.
4. The composition of claim 1 wherein the (a) ingredient has a Mn
of 400-1,300.
5. The composition of claim 1 wherein there is present 0.5-7.0 wt.
% of the (e) ingredient.
6. A combustion improving additive being the reaction product of
(1) a borated nitrogen-containing lubricating oil dispersant, and
(2) a phosphorus compound selected from the group consisting of (i)
zinc dialkyldithiophosphates, (ii) acid phosphates of the formula
(RX).sub.2P(:X)XH where R is H or C.sub.3-C.sub.20 hydrocarbyl, at
least one R being hydrocarbyl, and X may be O or S, (iii) amine
salts of the acid phosphates of (ii) wherein the amine is a primary
or secondary C.sub.3-C.sub.20 aliphatic or aromatic amine, and (iv)
phosphites of the formula P(OX').sub.3 wherein X' is H or
hydrocarbyl, at least one X' being a hydrocarbyl, the hydrocarbyl
being a C.sub.1-C.sub.20 aliphatic, aromatic or alkyl aromatic
hydrocarbyl group.
7. The additive of claim 6 wherein the dispersant is a borated
polyisobutenyl succinimide dispersant wherein the polyisobutenyl
has a Mn 450-2,500.
8. The additive of claim 6 wherein the dispersant contains 0.1 to
5.0 wt. % boron.
9. The additive of claim 6 wherein the phosphorus compound is a
zinc dialkyldithiophosphate.
10. The additive of claim 9 wherein the zinc dialkyldithiophosphate
is prepared from C.sub.4-C.sub.8 aliphatic alcohols.
11. A lubricating oil composition suitable for lubrication of both
two-cycle engines and small four-cycle engines of 3-25 horsepower
having a kinematic viscosity of at least 6.5 mm.sup.2/s (cSt) at
100.degree. C. which comprises an admixture of: (a) 3-50 wt. % of a
polybutene polymer having a Mn of about 300-1500; (b) 2-15 wt. % of
a normally liquid aliphatic hydrocarbon solvent having a boiling
point of up to 380.degree. C.; (c) 0.1 to 10% by weight of a
combustion improving additive being the reaction product of (1) a
borated nitrogen-containing lubricating oil dispersant, and (2) a
phosphorus compound selected from the group consisting of (i) zinc
dialkyldithiophosphates, (ii) acid phosphates of the formula
(RX).sub.2P(:X)XH where R is H or C.sub.3-C.sub.20 hydrocarbyl, at
least one R being hydrocarbyl, and X may be O or S, (iii) amine
salts of the acid phosphates of (ii) wherein the amine is a primary
or secondary C.sub.3-C.sub.20 aliphatic or aromatic amine, and (iv)
phosphites of the formula P(OX').sub.3 wherein X' is H or
hydrocarbyl, at least one X' being a hydrocarbyl, the hydrocarbyl
being a C.sub.1-C.sub.20 aliphatic, aromatic or alkyl aromatic
hydrocarbyl group. (d) 20 to 94.9% by weight of a mineral or
synthetic oil of lubricating viscosity; and (e) 0 to 20% by weight
of an additive package for two cycle lubricating oil additives,
such additives being present in an amount to provide their normal
attendant functions and enable the two-cycle lubricating oil
composition to satisfy the industry standards for two cycle
lubricating oil compositions.
12. The composition of claim 11 wherein the combustion improving
additive is the reaction product of borated polyisobutenyl (Mn
450-2500) succinimide dispersant.
13. The composition of claim 11 wherein the phosphorus compound is
zinc dialkyldithiophosphate.
14. A lubricating oil composition comprising an oil of lubricating
viscosity and the combustion improving additive of claim 6.
Description
[0001] This invention relates to novel combustion improver
additives and to lubricant compositions containing such additives
useful for lubricating small engines. More particularly the
invention relates to two-cycle oil characterized in that it
contains a combustion improver, and thereby provides an oil which
exhibits reduced combustion chamber and piston deposits for
gasoline fueled two-cycle engines, such as outboard motors,
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
exceeding 500 cc, generally over a range of 50-3000 cc. The
development of such high performance engines has created the need
for new two-cycle oil standards and test procedures.
[0002] Two-cycle engines are lubricated by mixing the fuel and
lubricant and allowing the mixed composition to pass through the
engine or by injecting the lubricant into the engine cylinders or
crankcases. 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.
[0003] This invention further relates to universal oils suitable
for lubricating both two-cycle engines and small four-cycle
engines, i.e., four-cycle engines of about 3-25 horsepower, which
contain a novel combustion improver additive.
[0004] The present invention is based on the discovery that the
reaction product of a borated nitrogen-containing lubricating oil
dispersant and certain phosphorus compounds functions as a highly
effective combustion improving additive for two-cycle or small
four-cycle engine oils.
[0005] Accordingly, in one embodiment of this invention there has
been discovered a two-cycle lubricating oil composition having a
kinematic viscosity of at least 6.5 mm.sup.2/s (cSt) at 100.degree.
C. comprising an admixture of:
[0006] (a) 3 to 50% 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;
[0007] (b) 2 to 45% by weight of a normally liquid hydrocarbon
solvent having a boiling point of up to 380.degree. C.;
[0008] (c) 0.1 to 10% by weight of a combustion improving additive
being the reaction product of (1) a borated nitrogen-containing
lubricating oil dispersant, and (2) a phosphorus compound selected
from the group consisting of (i) zinc dialkyldithiophosphates, (ii)
acid phosphates of the formula (RX).sub.2P(:X)XH where R is H or
C.sub.3-C.sub.20 hydrocarbyl, at least one R being hydrocarbyl, and
X may be O or S, (iii) amine salts of the acid phosphates of (ii)
wherein the amine is a primary or secondary C.sub.3-C.sub.20
aliphatic or aromatic amine, and (iv) phosphites of the formula
P(OX').sub.3 wherein X' is II or hydrocarbyl, at least one X' being
a hydrocarbyl, the hydrocarbyl being a C.sub.1-C.sub.20 aliphatic,
aromatic or alkyl aromatic hydrocarbyl group.
[0009] (d) 20 to 94.9% by weight of a mineral or synthetic oil of
lubricating viscosity; and
[0010] (e) 0 to 20% by weight of an additive package for two-cycle
lubricating oil additives, such additives being other than a
polybutene polymer and being present in an amount to provide their
normal attendant functions and to satisfy the industry standards
for two cycle lubricating oil compositions.
[0011] All percentages are by weight on an active ingredient basis,
based on the weight of the fully formulated lubricating oil
composition.
[0012] The mixture of polybutenes preferably useful in the
lubricating oil compositions of this invention is a mixture of
poly-n-butenes and polyisobutylene which normally results from the
polymerization of C.sub.4 olefins and generally will have a number
average molecular weight of about 300 to 1500 with a
polyisobutylene or polybutene having a number average molecular
weight of about 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 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".
[0013] A preferred polybutene polymer is a mixture of polybutenes
and polyisobutylene prepared from a C.sub.4 olefin refinery stream
containing about 6 wt. % to 50 wt. % isobutylene with the balance a
mixture of 2-butene (cis- and trans-) 1-butene and less than 1 wt.
% butadiene. Particularly, preferred is a polymer prepared from a
C.sub.4 stream composed of 6-45 wt. % isobutylene, 25-35 wt. %
butanes and 15-50 wt. % 1- and 2-butenes. The polymer is prepared
by Lewis acid catalysis.
[0014] 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 about
380.degree. C. at atmosphere pressure. Such a solvent must also
have a flash point in the range of about 60-120.degree. C. such
that the flash point of the two-cycle oil of this invention is
greater than 70.degree. C. Typical examples include kerosene,
hydrotreated kerosene, middle distillate fuels, isoparaffinic and
naphthenic aliphatic hydrocarbon solvents, dimers, and higher
oligomers of propylene, butenes 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 91.1-113.9.degree. C.
sold as "Exxsol D80" by ExxonMobil Chemical Company. Preferably,
there will be employed 5-40%, more preferably 10-40%, by weight of
the solvent or a mixture of solvents in the two cycle oils of this
invention.
[0015] The third component of the two-cycle oil of this invention
is a combustion improver additive which may be present in an amount
of 0.1 to 10 wt. %, preferably 0.5 to 2.5 wt. %, more preferably in
an amount of 0.75 to 2.0 wt. %.
[0016] The combustion improver additive is the reaction product of
a borated nitrogen-containing lubricating oil dispersant containing
about 0.1 to 5.0 wt. % boron with certain oil soluble phosphorus
compounds.
[0017] The nitrogen-containing lubricating oil dispersant comprises
an oil soluble polymeric hydrocarbon backbone having functional
groups that are capable of associating with particles to be
dispersed. Typically, the dispersants comprise amine, or amide,
moieties attached to the polymer backbone often via a bridging
group. The dispersant may be, for example, selected from oil
soluble salts, amino-esters, amides, imides, and oxazolines of long
chain hydrocarbon substituted mono and dicarboxylic acids or their
anhydrides; long chain aliphatic hydrocarbons having a polyamine
attached directly thereto; and Mannich condensation products formed
by condensing a long chain substituted phenol with formaldehyde and
polyalkylene polyamine, and Koch reaction products.
[0018] The oil soluble polymeric hydrocarbon backbone is typically
an olefin polymer, especially polymers comprising a major molar
amount (i.e. greater than 50 mole %) of a C.sub.2 to C.sub.18
olefin (e.g., ethylene, propylene, butylene, isobutylene, pentene,
octene-1, styrene), and typically a C.sub.2 to C.sub.5 olefin. The
oil soluble polymeric hydrocarbon backbone may be a homopolymer
(e.g., polypropylene or polyisobutylene) or a copolymer of two or
more of such olefins (e.g., copolymers of ethylene and an
alpha-olefin such as propylene and butylene or copolymers of two
different alpha-olefins). Other copolymers include those in which a
minor molar amount of the copolymer monomers, e.g., 1 to 10 mole %,
is an alpha, .omega.-diene, such as a C.sub.3 to C.sub.22
non-conjugated diolefin (e.g., a copolymer of isobutylene and
butadiene, or a copolymer of ethylene, propylene and 1,4-hexadiene
or 5-ethylidene-2-norbornene). Atactic propylene oligomer typically
having {overscore (M)}n of from 700 to 5000 may also be used as
described in EP-A-490454, as well as heteropolymers such as
polyepoxides.
[0019] One preferred class of olefin polymers is polybutenes and
specifically polyisobutenes (PIB) or poly-n-butenes, such as may be
prepared by polymerization of a C.sub.4 refinery stream. Another
preferred class of olefin polymers is ethylene alpha-olefin (EAO)
copolymers or alpha-olefin homo- and copolymers such as may be
prepared using the metallocene chemistry having in each case a high
degree (e.g. >30%) of terminal vinylidene unsaturation.
[0020] The oil soluble polymeric hydrocarbon backbone will usually
have number average molecular weight ({overscore (M)}n) within the
range of from 300 to 20,000. The {overscore (M)}n of the backbone
is preferably within the range of 500 to 10,000, more preferably
700 to 5,000 where the use of the backbone is to prepare a
component having the primary function of dispersancy. Hetero
polymers such as polyepoxides are also usable to prepare
components. Both relatively low molecular weight ({overscore (M)}n
500 to 1500) and relatively high molecular weight ({overscore (M)}n
1500 to 5,000 or greater) polymers are useful to make dispersants.
Particularly useful olefin polymers for use in dispersants have
{overscore (M)}n within the range of from 900 to 3000. Where the
component is also intended to have a viscosity modification effect
it is desirable to use higher molecular weight, typically with Mn
of from 2,000 to 20,000, and if the component is intended to
function primarily as a viscosity modifier then the molecular
weight may be even higher with an {overscore (M)}n of from 20,000
up to 500,000 or greater. The functionalized olefin polymers used
to prepare dispersants preferably have approximately one terminal
double bond per polymer chain.
[0021] The oil soluble polymeric hydrocarbon backbone may be
functionalized to incorporate a functional group into the backbone
of the polymer, or as one or more groups pendant from the polymer
backbone. The functional group typically will be polar and contain
one or more hetero atoms such as P, O, S, N or halogen. It can be
attached to a saturated hydrocarbon part of the oil soluble
polymeric hydrocarbon backbone via substitution reactions or to an
olefinic portion via addition or cycloaddition reactions.
Alternatively, the functional group can be incorporated into the
polymer in conjunction with oxidation or cleavage of the polymer
chain end (e.g., as in ozonolysis).
[0022] Useful functionalization reactions include: halogenation of
the polymer allylic to the olefinic bond and subsequent reaction of
the halogenated polymer with an ethylenically unsaturated
functional compound (e.g., maleation where the polymer is reacted
with maleic acid or anhydride); reaction of the polymer with an
unsaturated functional compound by the "ene" reaction absent
halogenation; reaction of the polymer with at least one phenol
group (this permits derivatization in a Mannich base-type
condensation); reaction of the polymer at a point of unsaturation
with carbon monoxide using a hydroformylation catalyst or a
Koch-type reaction to introduce a carbonyl group attached to a
--CH.sub.2-- or in an iso or neo position; reaction of the polymer
with the functionalizing compound by free radical addition using a
free radical catalyst; reaction with a thiocarboxylic acid
derivative; and reaction of the polymer by air oxidation methods,
epoxidation, chloroamination, or ozonolysis.
[0023] The functionalized oil soluble polymeric hydrocarbon
backbone is then further derivatized with a nucleophilic reactant
such as an amine, amino-alcohol, alcohol, metal compound or mixture
thereof to form a corresponding derivative. Useful amine compounds
for derivatizing functionalized polymers comprise at least one
amine group and can comprise one or more additional amine or other
reactive or polar groups. These amines may be hydrocarbyl amines or
may be predominantly hydrocarbyl amines in which the hydrocarbyl
group includes other groups, e.g., hydroxy groups, alkoxy groups,
amide groups, nitriles, imidazoline groups, and the like.
Particularly useful amine compounds include mono- and polyamines,
e.g., polyalkylene and polyoxyalkylene polyamines of about 2 to 60,
conveniently 2 to 40 (e.g., 3 to 20) total carbon atoms and about 1
to 12, conveniently 3 to 12, and preferably 3 to 9 nitrogen atoms
in the molecule. Mixtures of amine compounds may advantageously be
used, such as those prepared by reaction of alkylene dihalide with
ammonia. Preferred amines are aliphatic saturated amines,
including, e.g., 1,2-diaminoethane; 1,3-diaminopropane;
1,4-diaminobutane; 1,6-diaminohexane; polyethylene amines such as
diethylene triamine; triethylene tetramine; tetraethylene
pentamine; and polypropyleneamines such as 1,2-propylene diamine;
and di-(1,3-propylene) triamine.
[0024] A preferred group of dispersants includes those substituted
with succinic anhydride groups and reacted with polyethylene amines
(e.g., tetraethylene pentamine), aminoalcohols such as
trismethylolaminomethane, polymer products of metallocene catalyzed
polymerizations, and optionally additional reactants such as
alcohols and reactive metals. Also useful are dispersants wherein a
polyamine is attached directly to the backbone by the methods shown
in U.S. Pat. No. 5,225,092; and in U.S. Pat. No. 3,275,554 and U.S.
Pat. No. 3,565,804 where a halogen group on a halogenated
hydrocarbon is displaced with various alkylene polyamines.
[0025] Another class of dispersants comprises Mannich base
condensation products. Generally, these are prepared by condensing
about one mole of an alkyl-substituted mono- or polyhydroxy benzene
with about 1 to 2.5 moles of carbonyl compounds (e.g., formaldehyde
and paraformaldehyde) and about 0.5 to 2 moles polyalkylene
polyamine as disclosed, for example, in U.S. Pat. No. 3,442,808.
Such Mannich condensation products may include a polymer product of
a metallocene catalyzed polymerization as a substituent on the
benzene group or may be reacted with a compound containing such a
polymer substituted on a succinic anhydride, in a manner similar to
that shown in U.S. Pat. No. 3,442,808.
[0026] The borated dispersant is prepared by treating the
nitrogen-containing dispersant with a boron compound selected from
the group consisting of boron oxide, boron halides, boron acids and
esters of boron acids or highly borated low {overscore (M)}w
dispersant, in an amount to provide a boron to nitrogen mole ratio
of 0.01-3.0. Usefully the dispersants contain from about 0.1 to 5
wt. % boron based on the total weight of the borated dispersant.
The boron, which appears in the product as dehydrated boric acid
polymers (primarily (HBO.sub.2).sub.3), is believed to be attached
to the dispersant nitrogen atoms as amine salts e.g., a metaborate
salt. Boration is readily carried out by adding from about 0.05 to
4, e.g., 1 to 3 wt. % (based on the weight of acyl nitrogen
compound) of a boron compound, preferably boric acid, usually as a
slurry, to the nitrogen-containing dispersant and heating with
stirring at from 135.degree. to 190.degree. C., e.g., 140.degree.
to 170.degree. C., for from 1 to 5 hours followed by nitrogen
stripping. Alternatively, the boron treatment can be carried out by
adding boric acid to a hot reaction mixture of the dicarboxylic
acid material and amine while removing water. Additionally, other
finishing steps such as those disclosed in U.S. Pat. No. 5,464,549,
herein incorporated by reference, may be used.
[0027] Preferably, the combustion improver additive is prepared by
reacting or complexing a borated hydrocarbyl succinimide
lubricating oil dispersant wherein the hydrocarbyl has a Mn of
300-3,000 with certain oil-soluble phosphorus compounds. Preferably
the hydrocarbyl is a polyisobutenyl of Mn 300-3,000, more
preferably 450-2,500. These dispersants are well known in the art
and are formed by reacting a hydrocarbyl, e.g. polyisobutenyl
succinic anhydride with polyethylene amines such as tetraethylene
pentamine or diethylene triamine.
[0028] To form the combustion improver additive the dispersant is
reacted or complexed with certain oil-soluble phosphorus compounds
by heating the reactants together at a temperature of 50.degree. C.
to 70.degree. C. for a period of 15 to 60 minutes, preferably about
30 minutes. Formation of the stable complex or reaction product is
indicated by no evidence of separation upon cooling to room
temperature. The additives so produced are homogeneous, stable,
clear liquids at room temperature. The mole ratio of boron to
phosphorus compound may be 0.1:1 to 1.2:1, preferably 0.5:1 to 1:1.
The exact mechanism of the formation of the reaction or complexed
product is not completely understood.
[0029] Suitable phosphorus compounds for reaction with or
complexing with the dispersant are selected from the group
consisting of:
[0030] (i) oil soluble zinc dialkyldithiophosphates (ZDDP's) which
are prepared by reacting C.sub.3-C.sub.12, preferably
C.sub.4-C.sub.8, aliphatic alcohols with P.sub.2S.sub.5 to produce
dialkylthiophosphoric acids which are then reacted with zinc oxide
to produce the ZDDP's;
[0031] (ii) acid phosphates of the formula (RX).sub.2P(:X)XH where
R is H or C.sub.3-C.sub.20 hydrocarbyl, at least one R being a
hydrocarbyl, and X may be O or S, X is preferably O, the R
hydrocarbyl is preferably a C.sub.3-C.sub.12 alkyl group;
[0032] (iii) amine salts of the acid phosphates of (ii) wherein the
amine is a primary or secondary C.sub.3-C.sub.20 aliphatic or
aromatic amine, preferably a primary or secondary C.sub.3-C.sub.16
alkyl amine; and
[0033] (iv) phosphites of the formula P(OX').sub.3 wherein X' is H
or hydrocarbyl, at least one X' being a hydrocarbyl, the
hydrocarbyl being a C.sub.1-C.sub.20 aliphatic, such as alkyl or
alkenyl, aromatic or alkyl aromatic hydrocarbyl group, X' is
preferably a C.sub.1-C.sub.3 alkyl phenyl. Tricresyl phosphite is
particularly preferred.
[0034] The aforesaid combustion improver additives are considered
novel compositions of matter and as such constitute a further
embodiment of this invention.
[0035] In addition to the two-cycle oils and universal small engine
oils discussed herein, a still further embodiment of this invention
comprises an oil of lubricating viscosity comprising an effective
amount of the novel combustion improver additive of this invention,
such effective amounts being from 0.1 to 10.0 wt. %, such as 0.5 to
2.5 wt. %.
[0036] The fourth component of the lubricating compositions of this
invention is an oil of lubricating viscosity, that is, a viscosity
of about 20-180, preferably 55-180 cSt at 40.degree. C., to provide
a finished two-cycle oil in the range of 6.5-14 cSt at 100.degree.
C.
[0037] These oils of lubricating viscosity for this invention can
be natural or synthetic oils. Mixtures of such oils are also often
useful. Blends of oils may also be used as long as the final
viscosity is 20-180 cSt at 40.degree. C.
[0038] Natural oils include mineral lubricating oils such as liquid
petroleum oils and solvent-treated or acid-treated mineral
lubricating oils of the paraffinic, naphthenic or mixed
paraffinic-naphthenic types. Oils of lubricating viscosity derived
from coal or shale are also useful base oils.
[0039] Synthetic lubricating oils include hydrocarbon oils such as
esters, polymerized and interpolymerized olefins, alkylated
diphenyl ethers and alkylated diphenyl sulfides and the
derivatives, analogs and homologs thereof.
[0040] Oils made by polymerizing olefins of less than 5 carbon
atoms and mixtures thereof are typical synthetic polymer oils.
Methods of preparing such polymer oils are well known to those
skilled in the art as is shown by U.S. Pat. Nos. 2,278,445;
2,301,052; 2,318,719; 2,329,714; 2,345,574; and 2,422,443.
[0041] Alkylene oxide polymers (i.e., homopolymers, interpolymers,
and derivatives thereof where the terminal hydroxyl groups have
been modified by esterification, etherification, etc.) constitute a
preferred class of known synthetic lubricating oils for the purpose
of this invention, especially for use in combination with alkanol
fuels. They are exemplified by the oils prepared through
polymerization of ethylene oxide or propylene oxide, the alkyl and
aryl ethers of these polyoxyalkylene polymers (e.g., methyl
polypropylene glycol ether having an average molecular weight of
1000, diphenyl ether of polyethylene glycol having a molecular
weight of 500-1000, diethyl ether of polypropylene glycol having a
molecular weight of 1000-1500, etc.) or mono- and polycarboxylic
esters thereof, for example, the acetic acid esters, mixed
C.sub.3-C.sub.8 fatty acid esters, or the C.sub.13 Oxo acid diester
of tetraethylene glycol.
[0042] Another suitable class of synthetic lubricating oils
comprises the esters of dicarboxylic acids (e.g., phthalic acid,
succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic
acid, azelaic acid, suberic acid, sebacic acid, fumaric acid,
adipic acid, linoleic acid dimer, malonic acid, alkyl malonic
acids, alkenyl malonic acids, etc.) with a variety of alcohols
(e.g., butyl alcohol, hexyl alcohol, octyl alcohol, dodecyl
alcohol, tridecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol,
diethylene glycol monoether, propylene glycol, etc.). Specific
examples of these esters include dioctyl adipate,
di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate,
diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl
phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic
acid dimer, the complex ester formed by reacting one mole of
sebacic acid with two moles of tetraethylene glycol and two moles
of 2-ethylhexanoic acid and the like.
[0043] Esters useful as synthetic oils also include those made from
C.sub.5 to C.sub.18 monocarboxylic acids and polyols and polyol
ethers such as neopentyl glycol, trimethylol propane,
pentaerythritol, dipentaerythritol, tripentaerythritol, etc.
[0044] Unrefined, refined and rerefined oils, either natural or
synthetic (as well as mixtures of two or more of any of these) of
the type disclosed hereinabove can be used in the lubricant
compositions of the present invention. Unrefined oils are those
obtained directly from a natural or synthetic source without
further purification treatment. For example, a shale oil obtained
directly from retorting operations, a petroleum oil obtained
directly from primary distillation or an ester oil obtained
directly from an esterification process and used without further
treatment would be an unrefined oil. Refined oils are similar to
the unrefined oils except they have been further treated in one or
more purification steps to improve one or more properties. Many
such purification techniques are known to those of skill in the art
such as solvent extraction, secondary distillation, acid or base
extraction, filtration, percolation, etc. Rerefined oils are
obtained by processes similar to those used to obtain refined oils
which have been already used in service. Such rerefined oils are
also known as reclaimed or reprocessed oils and often are
additionally processed by techniques directed to removal of spent
additives and oil breakdown products.
[0045] The invention further comprises the presence of 0-20% by
weight of an additive package which contains one or more
conventional two-cycle lubricating oil additives, and these may be
any additive normally included in such lubricating oils for a
particular purpose. Preferably there is employed 0.5-15% by weight,
more preferably 0.5-7.0% by weight of the additive package.
[0046] Such conventional additives for the additive package
component which may be present in the composition of this invention
include corrosion inhibitors, oxidation inhibitors, friction
modifiers, dispersants, antifoaming agents, antiwear agents, pour
point depressants, metal detergents, rust inhibitors, lubricity
agents, which are preferred, and the like.
[0047] A preferred additive package for two-cycle engine oils for
air cooled engines will comprise (i) borated polyisobutenyl (Mn
400-2500, preferably Mn 950) succinimide present in such amount to
provide 0.2-5 wt. %, preferably 1-3 wt. % dispersant in the
lubricating oil and (ii) a metal phenate, sulfonate or salicylate
oil soluble detergent additive, which is a neutral metal detergent
or overbased such that the Total Base Number is 200 or less,
present in such amount so as to provide 0.1-2 wt. %, preferably
0.2-1 wt. % metal detergent additive in the lubricating oil. The
metal is preferably sodium, calcium, barium or magnesium. Neutral
calcium sulfurized phenates are preferred.
[0048] Corrosion inhibitors are present in amounts of 0.01-3 wt. %,
preferably 0.01-1.5 wt. %, and are illustrated by phosphosulfurized
hydrocarbons and the products obtained by reacting a
phosphosulfurized hydrocarbon with an alkaline earth metal oxide or
hydroxide. Another useful corrosion inhibitor is benzotriazole (35
wt. % active ingredient in propylene glycol).
[0049] Oxidation inhibitors are present in amounts of 0.01-5 wt. %,
preferably 0.01-1.5 wt. % and are antioxidants exemplified by
alkaline earth metal salts of alkylphenol thioesters having
preferably C.sub.5-C.sub.12 alkyl side chain such as calcium
nonylphenol sulfide, barium t-octylphenol sulfide,
dioctylphenylamines as well as sulfurized or phosphosulfurized
hydrocarbons and hindered phenols. Also included are oil soluble
antioxidant copper compounds such as copper salts of C.sub.10 to
C.sub.18 oil soluble fatty acids.
[0050] Friction modifiers are present in amounts of 0.01-3 wt. %,
preferably 0.01-1.5 wt. %, and include fatty acid esters and
amides, glycerol esters of dimerized fatty acids and succinate
esters or metal salts thereof.
[0051] Pour point depressants, also known as lube oil flow
improvers, are used in amounts of 0.01-2 wt. %, preferably 0.01-1.5
wt. %, and can lower the temperature at which the fluid will flow
and typical of these additives are C.sub.8-C.sub.18 or C.sub.14
dialkyl fumarate vinyl acetate copolymers, which are preferred,
polymethacrylates and wax naphthalene.
[0052] Foam control can also be provided by an anti-foamant of the
polysiloxane type such as silicone oil and polydimethyl siloxane;
acrylate polymers are also suitable. These are used in amounts of 5
to 25 ppm in the finished oil.
[0053] Anti-wear agents reduce wear of metal parts and
representative materials are zinc dialkyldithiophosphate, zinc
diaryl diphosphate, and sulfurized isobutylene. These are used in
amounts of 0.01-5 wt. %. But preferably, the two-cycle or universal
oils of this invention will not contain the foregoing zinc
dialkyldithiophosphate or zinc diaryl dithiophosphate anti-wear
agents nor any other anti-wear agent since the combustion improver
additive of this invention will also provide adequate anti-wear
properties to the oils.
[0054] Lubricity agents useful in this invention may be selected
from a wide variety of oil soluble materials. Generally, they are
present in an amount of 1-20 wt. %, preferably about 5-15 wt. %.
Lubricity agents include polyol ethers and polyol esters such as
polyol esters of C.sub.5-C.sub.15 monocarboxylic acids,
particularly pentaerythritol, trimethylol propane and neopentyl
glycol synlube esters of such acids, wherein the ester has a
viscosity of at least 9 mm.sup.2/s (cSt) at 100.degree. C., natural
oils such as bright stock which is the highly viscous mineral oil
fraction derived from the distillation residues formed as a result
of the preparation of lubricating oil fractions from petroleum.
[0055] A preferred lubricity agent is an
.alpha.-olefin/dicarboxylic acid ester copolymer having a viscosity
of 20 to 50 mm.sup.2/s (cSt) at 100.degree. C., which is
represented by the following general formula: 1
[0056] wherein R.sub.1 is a straight-chain or branched alkyl group;
X.sub.1, X.sub.2, X.sub.3 and X.sub.4 may be the same or different
and are each hydrogen, a straight-chain or branched alkyl group, a
group represented by the formula --R.sub.2--CO.sub.2R.sub.3 or an
ester group represented by the formula --CO.sub.2R.sub.4 wherein
R.sub.2 is a straight-chain or branched alkylene group, R.sub.3 and
R.sub.4 may be the same or different and are each a straight-chain
or branched alkyl group, any two of X.sub.1, X.sub.2, X.sub.3 and
X.sub.4 are each said ester group; and x and y may be the same or
different and are each a positive number.
[0057] The structure above represented by the formula 2
[0058] is derived from an .alpha.-olefin, and the number of carbon
atoms of the .alpha.-olefin is preferably 3 to 20, still preferably
6 to 18. Examples of the .alpha.-olefin include propylene,
1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene,
1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene,
1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene,
1-nonadecene and 1-eicosene.
[0059] The structure above represented by the formula 3
[0060] is derived from an ester of a dicarboxylic acid having
ethylene linkage. Examples of the dicarboxylic acid include maleic
acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic
acid. The alcohol is preferably one having 1 to 20 carbon atoms,
still preferably one having 3 to 8 carbon atoms. Examples of the
alcohol include methanol, ethanol, propanol, butanol (preferred),
pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol,
dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol,
heptadecanol, octadecanol, nonadecanol and eicosanol. The component
(A) is prepared by copolymerizing the above-described
.alpha.-olefin with the above-described ester of a dicarboxylic
acid. This process is described in detail in Japanese Patent
Application Laid-Open Gazette No. (Sho.) 58-65246. The molar ratio
of the .alpha.-olefin (x) to the ester (y) of a dicarboxylic acid
is preferably x:y=1:9 to 9:1. The number average molecular weight
of the ester copolymer is preferably 1000 to 3000. The kinematic
viscosity should be 20 to 50 mm.sup.2/s (cSt) at 100.degree. C.,
preferably 30 to 40 mm.sup.2/s (cSt) at 100.degree. C. These
materials are available under the trademark "Ketjenlube" from Akzo
Chemicals, Inc.
[0061] Other suitable lubricity agents include phosphorus
containing additives such as dihydrocarbyl hydrocarbyl phosphonates
and sulfur containing lubricity agents such as sulfurized fats,
sulfurized isobutylene, dialkyl polysulfides, and sulfur bridged
phenols such as nonylphenol polysulfide.
[0062] Other suitable lubricity agents include fatty acids
(including dimers and trimers thereof), fatty ethers, fatty esters
and methoxylated fatty ethers and esters such as ethylene
oxide/propylene oxide copolymers and fatty esters of these
materials as well as natural materials such as vegetable oils,
glycerides and the like. Still further suitable lubricity agents
include borate esters such as tricresyl borate ester condensates
and phosphorus containing esters such as tricresyl phosphate and
other trialkyl and triaryl phosphites and phosphates. Other
lubricity agents include orthophosphate or sulfate salts of primary
or secondary aliphatic amines having 4 to 24 carbon atoms, dialkyl
citrates having an average of from 3 to 12 carbon atoms in the
alkyl groups, aliphatic dicarboxylic acids and esters thereof,
chlorinated waxes and polyhaloaromatic compounds such as
halogenated benzenes and naphthalenes.
[0063] The two-cycle lubricating oil compositions of the present
invention will mix 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 by ASTM specification D-439-73. Such fuels can also
contain non-hydrocarbonaceous materials such as alcohols, ethers,
organic nitro compounds and the like, e.g., methanol, ethanol,
diethyl ether, methylethyl ether, nitromethane 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 gasoline and
ethanol, diesel fuel and ether, gasoline and nitromethane, etc.
Gasoline is preferred, i.e., mixture of hydrocarbons having an ASTM
boiling point of 60.degree. C. at the 10% distillation point to
about 205.degree. C. at the 90% distillation point. Lead-free
gasoline is particularly preferred.
[0064] The two-cycle lubricants of this invention are used in
admixture with fuels in amounts of about 20 to 250 parts by weight
of fuel per 1 part by weight of lubricating oil, more typically
about 30-100 parts by weight of fuel per 1 part by weight of oil.
They may also be used by directly injecting the lubricant into the
cylinders or crankcases of a two-cycle engine.
[0065] The combustion engine improver additives of the invention
are also effective for the preparation of lubricating oils
effective for the lubrication of small four-cycle engines, i.e.,
engines of 3-25 horsepower (hp) (2.24-18.64 kW), preferably 4-6 hp
(2.98-4.53 kW), or 100 to 200 cc engines, since the combustion
improver additive will provide the necessary anti-wear properties
to the four-cycle oil composition. Thus, it is possible in
accordance with the present invention to formulate so-called
universal oils, i.e., oils suitable for both two-cycle and small
four-cycle engines. Such universal oils will have the same
ingredients as the two cycle oils disclosed above, but will contain
2 to 15% by weight of solvent and will preferably be free of any
anti-wear additives such as zinc-containing anti-wear additives
(other than the combustion improving additives of this
invention).
[0066] Accordingly, there has further been discovered a universal
lubricating oil composition suitable for lubrication of two-cycle
engines and small four-cycle engines of 3-25 horsepower (2.24-18.64
kW) having a kinematic viscosity of at least 6.5 mm.sup.2/s (cSt)
at 100.degree. C. comprising an admixture of:
[0067] (a) 3 to 50% 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;
[0068] (b) 2 to 15% by weight of a normally liquid hydrocarbon
solvent having a boiling point of up to 380.degree. C.;
[0069] (c) 0.1 to 10% by weight of a combustion improving additive
being the reaction product of (1) a borated nitrogen-containing
lubricating oil dispersant, and (2) a phosphorus compound selected
from the group consisting of (i) zinc dialkyldithiophosphates, (ii)
acid phosphates of the formula (RX).sub.2P(:X)XH where R is H or
C.sub.3-C.sub.20 hydrocarbyl, at least one R being hydrocarbyl, and
X may be O or S, (iii) amine salts of the acid phosphates wherein
the amine is a primary or secondary C.sub.3-C.sub.20 aliphatic or
aromatic amine, and (iv) phosphites of the formula P(OX').sub.3
wherein X' is H or hydrocarbyl, at least one X' being a
hydrocarbyl, the hydrocarbyl being a C.sub.1-C.sub.20 aliphatic,
aromatic or alkyl aromatic hydrocarbyl group.
[0070] (d) 20 to 94.9% by weight of a mineral or synthetic oil of
lubricating viscosity; and
[0071] (e) 0 to 20% by weight of an additive package for two cycle
lubricating oil additives, such additives being other than a
polybutene polymer and being present in an amount to provide their
normal attendant functions and to satisfy the industry standards
for two cycle lubricating oil compositions.
[0072] Preferred universal oils will comprise a combustion
improving additive being the reaction product of a zinc dialkyl
dithiophosphate and the borated dispersant.
[0073] The invention is further illustrated by the following
examples which are not to be considered as limitative of its scope.
Percentages are by weight.
EXAMPLES
[0074] A two-cycle test oil was prepared composed of the
following:
[0075] (a) 5.0% of a 50.5% mineral oil solution of a Mn 950
polyisobutenyl succinimide dispersant;
[0076] (b) 5.0% of a 75% mineral oil solution of an Mn 700
polyisobutenyl succinimide dispersant;
[0077] (c) 10.0% of Mn 950 polyisobutylene;
[0078] (d) 25.0% of a naphthenic type hydrocarbon solvent b.p.
range 91.1-113.9.degree. C., sold as "Exxol D80" by ExxonMobil
Chemical Co.
[0079] (e) 5.0% of a brightstock lubricity agent;
[0080] (f) 50.0% mineral lubricating oil.
[0081] Three combustion improver additives were prepared identified
as A, B and C below. Each was the reaction product of a 50%/50% by
weight mixture of a borated polyisobutenyl (Mn 950) succinimide
dispersant containing 1.3 wt. % boron with:
[0082] A: an acid phosphate amine salt formed by first reacting a
dialkyldithiophosphoric acid made from methylisobutyl carbinol with
propylene oxide and P.sub.2O.sub.5 and partially neutralizing it
with a C.sub.12/C.sub.14 t-alkyl primary amine; the amine salt is
provided as a 75% by weight solution in mineral oil;
[0083] B: a 74% by weight solution in mineral oil of a ZDDP
prepared from P.sub.2S.sub.5, 2-methyl-1-propanol, pentan-1-ol and
2-methyl-butanol;
[0084] C: an 80% solution in kerosene of an amine salt of mixed
acid alkyl phosphates.
[0085] A sample of the test oil above containing 1.48 wt. % of
Additive B was subjected to a laboratory oil burning test, the
procedure for which is as follows:
[0086] A one gallon can cap, if previously used, was cleaned using
steel wool and powdered cleanser, dried with a paper towel and
scrubbed with an IOSOL 1520 wetted paper towel. It was then heated
on the hot plate, cooled in a desiccator and weighed to 4 places.
(Note: carbonaceous deposits in the cap grooves were not entirely
removed by this procedure. Occasionally any excessive build-up was
removed with a steel spatula.)
[0087] Seven milliliters of the oil to be evaluated were syringed
into the cap. The cap was then centered in the 6 oz. can and the
two containers were in turn centered on the preheated hot plate
housed in a fume hood.
[0088] After two minutes preheat, the oil was ignited with a butane
fire starter gun. A second stop watch was started and the fume hood
doors closed. The air draft through the fume hood, the relative
humidity, lab temperature and atmospheric pressure were
recorded.
[0089] The time to burn-out was recorded. The can was then removed
from the hot plate with tongs and the cap again placed in the
desiccator using tweezers. When cool, the cap was re-weighed and
the residue/100 ml of oil calculated.
[0090] The results are in Table 1.
[0091] Table 2 shows the results for Additives A, B and C when
added to "Motomaster Premium Outboard Motor Oil", a two cycle oil
commercially available from Canadian Tire Corp. and comparison was
made with "Molyvan-L", a known combustion improver. Table 2 shows
that Additives A, B and C exhibit satisfactory performance.
1TABLE 1 Burning Test Results for Additive B in Test Oil Burn Time
Total Residue Test No. Treat, Wt. % Min:sec g/100 ml oil 1 None
8:14 5.71 2 1.48 9:00 4.68 3 1.48 8:56 4.61
[0092]
2TABLE 2 Burning Test Results for Combustion Improvers Added to
"Motomaster Premium" Burn Time Total Residue Test No. Additive
Treat, Wt. % Min:sec g/100 ml oil 1 None -- 8:19 7.03 2 Molyvan-L
.sup.(1) 1.09 7:57 4.72 3 A 1.09 8:03 6.76 4 A 2.15 7:48 6.12 5 B
1.09 8:47 4.92 6 B 2.15 8:55 4.24 7 C 2.15 8:06 5.92 .sup.(1) A
known combustion improver in our burning test: sulphurized oxy
molybdenum dialkyldithiophosphate.
* * * * *