Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing boron
Reexamination Certificate
2001-05-01
2003-02-25
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing boron
C508S591000, C548S405000
Reexamination Certificate
active
06525004
ABSTRACT:
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.
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.
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.
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.
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
2
/s (cSt) at 100° C. comprising an admixture of:
(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;
(b) 2 to 45% by weight of a normally liquid hydrocarbon solvent having a boiling point of up to 380° 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)
2
P(:X)XH where R is H or C
3
-C
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
3
-C
20
aliphatic or aromatic amine, and (iv) phosphites of the formula P(OX′)
3
wherein X′ is H or hydrocarbyl, at least one X′ being a hydrocarbyl, the hydrocarbyl being a C
1
-C
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 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.
All percentages are by weight on an active ingredient basis, based on the weight of the fully formulated lubricating oil composition.
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
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”.
A preferred polybutene polymer is a mixture of polybutenes and polyisobutylene prepared from a C
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
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.
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° C. at atmosphere pressure. Such a solvent 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, 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° 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.
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. %.
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.
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.
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
2
to C
18
olefin (e.g., ethylene, propylene, butylene, isobutylene, pentene, octene-1, styrene), and typically a C
2
to C
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, &ohgr;-diene, such as a C
3
to C
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
Hartley Rolfe J.
Rea Salvatore
Stover William H.
Infineum International Inc.
McAvoy Ellen M.
LandOfFree
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