EP0957153A1 - Detergents comprising low sulfur, alkaline earth alkyl salicylates and their use in low sulfur lubricating compositions for two-stroke engines - Google Patents

Abstract

The detergent additive for lubricant compositions of low sulfur content comprises a non-sulfurized alkaline earth alkylsalicylate. The compositions are used in air-cooled two-stroke engines. Independent claims are also included for the lubricant composition, method of lubrication and an additive concentrate of low sulfur concentration.

Description

The present invention relates to compositions low sulfur lubricants having excellent detergency properties suitable for use in two-stroke engines, at useful low sulfur detergency additives in these low-content lubricating compositions sulfur, to fuels containing these additives detergency with low sulfur content, and concentrates of these low content detergency additives in sulfur.

BACKGROUND OF THE INVENTION

Over the past several decades the use of two-stroke internal combustion engines spark increased steadily. We find them currently in motor mowers and others garden equipment equipped with a motor, saws motor chains, pumps, generators electric, marine outboard motors, snowmobiles, mopeds and the like.

The growing use of two-cycle engines time, coupled with the increasing severity of conditions in which they are put into operation, has led to an increasing demand for oils to lubricate adequately such motors. Among the problems associated with two-stroke cycle engines we find the seizure, wear and and lubricity of the piston. Lubricating oils often contain sulfur, a key element of anti-wear performance. A lot of the contribution of sulfur comes from additives detergent-dispersants used in oils lubricants. However, the sulfur level has become environmentally sensitive and a shift towards lower sulfur levels is increasing. One of coaches was the presence of low base oil sulfur content in this part of the world. The low-grade lubricating oil additive packaging sulfur are not common.

The unique issues and techniques associated with lubrication of two-stroke cycle engines led recognition by those specializing in the art of two-cycle cycle engine lubricants as a separate type of lubricant. See, for example, US patents 3,085,975; 3,004,837; and 3,753,905.

US Patent 4,663,063 describes a functional fluid for a two-cycle engine having a base oil and a combination of an alkylated phenol and a polyalkylene polyamine.

This patent discloses that the metal thiocarbamates are useful as agents of extreme pressure.

US Patent 5,516,444 describes a functional fluid for a two-cycle engine having a base oil and a compound containing acylated nitrogen having a oil-soluble olefinic substituent and at least an ashless detergent / dispersant. This patent teaches that compounds containing molybdenum and molybdenum / sulfur are some of the antiwear agents to lubricity useful in this invention.

US Patent 5,458,807 describes an oil composition lubricant useful in automobiles and various engines industrial internal combustion. This composition lubricating oil has a base oil, a derivative of a boron compound of an alkenyl succinimide, a metal salt of alkaline earth salicylic acid, and a compound of molybdenum.

US Patent 5,688,751 describes salicylate salts of alkali metal as lubricating additives for two-cycle motors.

SUMMARY OF THE INVENTION

The present invention provides a detergent additive to low sulfur content (less than 0.2%) specially useful in a lubricating composition used in two-cycle air-cooled cycle engines. This low sulfur detergent additive includes a unsulfurized alkaline earth alkylsalicylate and optionally a molybdenum compound. An alkylphenol and an alkaline earth alkylphenate can also be present in the low detergent additive sulfur.

Preferably, the alkaline earth alkylsalicylate not sulfur is calcium alkylsalicylate in which the mole ratio of the aromatic ring alkylsalicylate unique to double aromatic alkylsalicylate in said unsulfurized alkaline earth alkylsalicylate is at least 8: 1.

The present invention also provides a composition low sulfur lubricant suitable for two-cycle air-cooled cycle engines. This lubricant composition in a majority amount oil with low sulfur viscosity lubricant and a minor amount of the additive low sulfur detergent. Preferably, the lubricating composition also contains a quantity minority of a non-aromatic solvent, a quantity minority of a polyisobutene, and / or an amount minority of an ashless dispersant. The composition lubricating oil can be produced by mixing together a majority amount of the oil from lubricating viscosity, of a minor amount low sulfur detergency additives, and preferably from minority amounts other additives, such as a non-aromatic solvent, polyisobutene, and an ashless dispersant. The low sulfur lubricant composition can be used to lubricate a two cycle engine air-cooled time by supplying the composition lubricant to the crankcase and putting engine operation or by supplying the composition of lubricant in the fuel and putting engine running.

The present invention also provides a concentrate additives suitable for mixing with base oil to provide lubricating oils that can be used to lubricate two-cycle engines air-cooled time. This additive contains a minority amount of an organic diluent, more than 20 80% of the low sulfur detergent and preferably a non-aromatic solvent, a polyisobutene, and / or an ashless dispersant.

DETAILED DESCRIPTION OF THE INVENTION

In its broadest aspect, the present invention involves a low sulfur detergent additive having excellent detergency properties when used in a low lubricating composition sulfur content for cooled two-stroke engines to the air. The low sulfur detergent additive includes an unsulfurized alkaline earth alkylsalicylate and optionally a molybdenum compound.

Before discussing the invention in more detail, following terms will be defined:

DEFINITIONS

As used here the following terms have the following meanings unless otherwise expressly indicated:

The term "low sulfur" means less than 0.2% sulfur, including no sulfur.

The term "alkylphenol" means a phenol group having one or more alkyl substituents; at least one of which has a sufficient number of carbon atoms to impart a oil solubility in phenol.

The term "alkaline earth metal" means calcium, barium, magnesium, and strontium.

The term "alkaline earth alkylphenate" means a metallic salt of an alkaline earth of an alkylphenol.

The term "alkaline earth alkylsalicylate" means a alkali earth metal salt of an acid alkylsalicylic.

The term "single aromatic ring alkylsalicylate alkaline earth "means an earth alkylsalicylate alkaline having only a salicylic alkyl anion for each base cation of alkaline earth metal. Thus one mole of alkylsalicylate with an aromatic cycle single alkaline earth will contain one mole of cycle aromatic and one mole of earth base cation alkaline. So an aromatic ring alkylsalicylate unique calcium would have an aromatic cycle for each calcium ion.

The term "double-aromatic alkylsalicylate of alkaline earth "means an earth alkylsalicylate alkaline having two salicylic alkyl anions for each alkali earth metal base cation. So one mole of alkylsalicylate with a double aromatic ring of alkaline earth will contain two moles of aromatic cycle and one mole of alkaline earth base cation. So, an aromatic calcium double alkylsalicylate will have two aromatic cycles for each calcium ion.

The term "Base Number" or "BN" refers to the basic amount equivalent to milligrams of KOH in one gram of sample. So BN numbers more high reflect more alkaline products, and therefore a higher alkalinity reserve. BN of a sample can be determined by ASTM test # D2896 or any other equivalent procedure.

Unless otherwise specified, all percentages are in percent weight and all weights are in number average molecular weight.

LUBRICATING VISCOSITY BASE OIL

The present invention relates to compositions lubricating oil and lubricating fuels suitable for use in twin engines time. Lubricating compositions useful for two-stroke cycle engines will consist of a majority amount by weight of at least one oil of base of lubricating viscosity and a quantity minority of the present additives, sufficient for check the bonding of the piston ring, reduce the rust formation, and promote general cleanliness motors.

The lubricating compositions and methods of this invention employ oils of lubricating viscosity, including natural lubricating oils or synthetics and their mixtures. While oils from conventional bases may contain 0.4% sulfur, the base oils of the present invention should contain less than 0.2% sulfur, preferably less than 0.1% sulfur. Natural oils include, for example, animal oils, vegetable oils, mineral oils, mineral oils treated with a solvent or an acid, and oils derived from coal or shale. Synthetic lubricating oils include, for example, hydrocarbon oils, halo-substituted hydrocarbon oils, polymers alkylene oxides, esters of mono and di-carboxylic acids and polyols, acid esters containing phosphorus, tetrahydrofurans polymers, and silicon-based oils. Since synthetic base oils do not contain typically no sulfur, they can be used to make a formulation with very low content sulfur.

LOW SULFUR DETERGENT ADDITIVE

The low sulfur detergent additive from present invention includes an earth alkylsalicylate unsulfurized alkaline and optionally a compound of molybdenum.

NON-SULFUR ALKALINE EARTH ALKYLSALICYLATE

Alkylsalicylates of alkaline earth sulfur and not sulfur are well known. Such alkylsalicylates are usually double-core alkylsalicylates aromatic, but single-core alkylsalicylates aromatic are also known. Preferably, the unsulfurized alkaline earth alkylsalicylate is calcium alkylsalicylate.

Preferred process for producing unsulfurized alkaline earth alkylsalicylates

(a) de 40% à 60% d'alkylphénol,

(b) de 10% à 40% d'alkylphénate de terre alcaline, et

(c) de 20% à 40% d'alkylsalicylate à noyau aromatique unique de terre alcaline.

A preferred process for producing unsulfurized alkaline earth alkylsalicylates can be characterized by its unique composition, with much more alkaline earth alkylphenol and alkyl salicylate than when produced by other routes. The reaction product has the following composition:

(a) from 40% to 60% of alkylphenol,

(b) from 10% to 40% of alkaline earth alkylphenate, and

(c) from 20% to 40% of alkylsalicylate with a single aromatic nucleus of alkaline earth.

Unlike other processes for producing alkaline earth alkylsalicylates, this product reaction can be characterized in that it contains only minor amounts of alkylsalicylate to double aromatic alkaline earth cycle. The report single aromatic ring alkylsalicylate molar the aromatic double ring alkylsalicylate and at least minus 8: 1.

Neutralization step

In the first step, the alkylphenols are neutralized using an alkaline earth base in the presence of at least one C ₁ to C ₄ carboxylic acid. This reaction is carried out in the absence of an alkaline base, and in the absence of dialcohol or of monoalcohol.

Alkylphenols contain up to 85% alkylphenol linear (preferably at least 35% alkylphenol linear) in a mixture with at least 15% branched alkylphenol. Preferably, the alkyl radical linear contains 12 to 40 carbon atoms, plus preferably 18 to 30 carbon atoms. The radical branched alkyl contains at least nine carbon atoms, preferably 9 to 24 carbon atoms, more preferably 10 to 15 carbon atoms.

The use of an alkylphenol containing at least 35% a long linear alkylphenol (18 to 30 atoms of carbon) is particularly attractive because a long linear alkyl chain promotes compatibility and the solubility of additives in oils lubricants. However, the presence of alkyl radicals relatively heavy linear in alkylphenols makes the latter less reactive than alkylphenols branched, therefore requires the use of harder reaction to reach about their neutralization with an alkaline earth base.

Branched alkylphenols can be obtained by phenol reaction with a branched olefin from usually propylene. They consist of a mixture of monosubstituted isomers, the vast majority of substituents being in the para position, very few being in ortho position, and barely a few in position meta. This makes them relatively reactive towards a alkaline earth base, since the phenol function is practically devoid of steric hindrance.

On the other hand, linear alkylphenols can be obtained by reaction of phenol with an olefin linear, generally originating from ethylene. They consist of a mixture of monosubstituted isomers in which the proportion of linear alkyl substituents at the ortho, para, and meta positions is much more evenly distributed. This makes them much less reactive towards an alkaline earth base since the phenol function is much less accessible due considerable steric hindrance, due to the presence of closer alkyl substituents and generally heavier.

The alkaline earth bases that can be used to implement this step include oxides or hydroxides of calcium, magnesium, barium, strontium and especially calcium oxide, calcium hydroxide, magnesium oxide, and their mixtures. In one embodiment, lime off (calcium hydroxide) is preferred.

The C ₁ -C ₄ carboxylic acids used in this step include formic, acetic, propionic and butyric acid, and can be used alone or as a mixture. Preferably, a mixture of acids is used, preferably a mixture of formic acid / acetic acid. The molar ratio of formic acid / acetic acid should be from 0.2: 1 to 100: 1, preferably between 0.5: 1 and 4: 1, and most preferably 1: 1. Carboxylic acids act as transfer agents, assist in the transfer of alkaline earth bases to an organic reagent.

The neutralization operation is carried out at a temperature of at least 200 ° C, preferably at least 215 ° C, and more preferably at least 240 ° C. The pressure is gradually reduced below the atmospheric pressure so as to distill the water from the reaction. In accordance with neutralization must be carried out in the absence of any solvent which can form a azeotropic with water. Preferably the pressure is reduced to no more than 7000 Pa (70 minibars).

(1) base de terre alcaline/alkylphénol de 0,2:1 à 0,7:1, de préférence 0,3:1 à 0,5:1 ; et

(2) acide carboxylique/alkylphénol de 0,01:1 à 0,5:1, de préférence de 0,03:1 à 0,15:1.

The quantities of reagents used must correspond to the following molar ratio:

(1) alkaline earth / alkylphenol base from 0.2: 1 to 0.7: 1, preferably 0.3: 1 to 0.5: 1; and

(2) carboxylic acid / alkylphenol from 0.01: 1 to 0.5: 1, preferably from 0.03: 1 to 0.15: 1.

Preferably, at the end of this neutralization step the alkylphenate obtained is maintained for a period not exceeding fifteen hours at a temperature of minus 215 ° C and at an absolute pressure between 5,000 and 105 Pa (between 0.05 and 1.0 bar). More preferably, at the end of this alkylphenate neutralization step obtained is maintained for between two and six hours at an absolute pressure between 10,000 and 20,000 Pa (between 0.1 and 0.2 bar).

By making the operations implemented at a sufficiently high temperature and that the pressure in the reactor is gradually reduced below the atmospheric pressure the neutralization reaction is implemented without the need to add a solvent which forms an azeotrope with the water formed during this reaction.

Carboxylation step

The carboxylation step is carried out by simply bubbling of carbon dioxide in the reaction medium from the previous neutralization step and is continued to at least 20 mole% of the alkylphenate into alkylsalicylate (measured as acid salicylic by a potentiometric determination). It must occur under pressure so as to avoid any decarboxylation of the alkylsalicylate which forms.

Preferably, at least 22 mol% of the alkylphenols of are converted to alkylsalicylate using carbon dioxide at a temperature between 180 ° and 240 ° C, under pressure in the range above from atmospheric pressure to 15 x 105 Pa (15 bar) for a period of one to eight hours.

Alternatively, at least 25 mole% of starting alkylphenols are converted to alkylsalicylate using carbon dioxide at a temperature equal to or greater than 200 ° C under a pressure of 4 x 105 Pa (4 bars).

Filtration stage

The purpose of the filtration step is to eliminate sediments, and more particularly carbonate crystalline calcium, which may have formed during previous steps, and which can cause blockage filters installed in the oil circuits lubricant.

MOLYBDENE COMPOUNDS

Suitable molybdenum compounds which can be used in the invention include, for example, the molybdenum dithiophosphate (MoDTP) and the molybdenum dithiocarbamate (MoDTC). This MoDTP includes a dialkyl (or diaryl) molybdenum dithiophosphate such as molybdenum diisopropyldithiophosphate, di- (2-ethylhexyl) molybdenum dithiophosphate and di- (nonylphenyl) molybdenum dithiophosphate. The MoDTC includes a molybdenum dialkyldithiocarbamate such as molybdenum dibutyldithiocarbamate, di- (2-ethylhexyl) molybdenum dithiocarbamate and the molybdenum dilauryldithiocarbamate. Other compounds molybdenum include molybdenum oxysulfides and Molyvan® 855 (a non-phosphorus molybdenum compound not sulfur sold by R.T. Vanderbilt Company).

The amount of molybdenum compounds containing sulfur (such as molybdenum dithiophosphates, molybdenum dithiocarbamates, the oxidisulfides of molybdenum) should be kept low so that the sulfur in the lubricating oil composition will less than 0.2%.

OTHER ADDITIVE COMPONENTS NON-AROMATIC SOLVENT

The compositions of the invention can optionally contain a minor amount of a non-solvent aromatic. The solvent is used just to adjust the viscosity of the finished oil. It must be non-aromatic so as to minimize smoke from exhausts. The suitable non-aromatic solvents include a flavored aliphatic distillate in the range of 200 ° to 240 ° C.

POLYISOBUTYLENE

The compositions of the present invention can optionally contain up to 10% of a polyisobutylene having a molecular weight of 350 to 2000, preferably around 950. This polyisobutylene is present in an amount up to 10%, preferably up to 7%, more preferably 5%, more preferably up to 3%. Polybutylene acts to improve the lubricating power and anti-friction activity of lubricant.

DISPERSANT WITHOUT ASHES

A wide variety of ashless dispersants / detergents can be used in this invention. Suitable dispersants / detergents are nitrogen-based compounds which have a basic nitrogen content as measured by ASTM D-664 or D-2896. They are preferably soluble in oil. Typical compositions are succinimides, carboxylic acid amides, hydrocarbyl monoamines, hydrocarbyl polyamines, Mannich bases, phosphoramides, phosphonamides, dispersing viscosity index boosters, and mixtures thereof. These basic nitrogen-containing compounds are described below. One of the nitrogen-containing compositions can be post-treated using procedures well known in the art as long as the compositions continue to contain base nitrogen. The post-treatment can be accomplished by bringing the compound containing the basic nitrogen into contact with the compound (s) after treatment concurrently or in any sequence. Suitable post-treatment compounds include urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon substituted succinic anhydrides, nitriles, epoxides, boron compounds, organic phosphorus, inorganic phosphorus compounds (such as H ₃ PO ₃ , H ₃ PO ₄ , etc.) or the like, and mixtures thereof. These post-treatments are particularly applicable to succinimide and Mannich base compositions.

Mono and poly succinimides which can be used as ashless dispersants in this invention are described in numerous references and are well known in the art. Some basic types succinimides and related materials encompassed by the art term "succinimide" are described in U.S. Patent Nos. 3,219,666; 3,172,892; and 3,272,746, of which disclosures are incorporated herein by reference. The term "succinimide" is understood in art as including many of the amide, imide, and amidines which can also be formed. The product predominant however is a succinimide and this term has generally accepted as meaning the product of a reaction of a succinic acid or anhydride alkenyl substituted with a nitrogen containing compound. The preferred succinimides, due to their commercial availability, are these succinimides prepared from succinic hydrocarbyl anhydride, where the hydrocarbyl group contains from about 60 to about 350 carbon atoms, and one ethylene amine, said ethylene amine being specially characterized by ethylene diamine, diethylene triamine, triethylene tetramine, and tetraethylene pentamine. We particularly prefer these succinimides prepared for from polyisobutenyl succinic anhydride of approximately 70 to 128 carbon atoms and tetraethylene pentamine or those called "polyamine bottoms" resulting from the synthesis of polyethylene amine. These "polyamine bottoms" contain predominantly Pentaethylene hexamine and tetraethylene pentamine, and less ethylene polyamine lighter and cyclic condensation products containing piperazine rings.

Also included in the term "succinimide" are co-oligomers of a hydrocarbyl acid or anhydride succinic and a secondary polyamine containing at minus one tertiary amino nitrogen in addition to two or plus secondary amino groups. Usually this composition has number average molecular weight (Mn) between 1500 and 50000. A typical compound would be that prepared by reaction of polyisobutenyl anhydride succinic and ethylene dipiperazine.

OTHER ADDITIVES

Other additives that are particularly useful in the present invention are imidazolines, such as 2-methylimidazoline, and polyalkylamines, such as described in US Patent No. 4,713,188 which is incorporated by reference for all purposes.

The compositions of the present invention can also contain up to 10% by weight of a functionalized polyisobutylene having a weight number average molecular from 400 to 2500, preferably about 1300. The functional group for olefin is based on amine. This functionalized polyisobutylene is present in an amount of up to 15% by weight, preferably up to 10%, preferably around 5% in weight. Functionalized polsobutylene is therefore a reaction product of olefin and polymers olefinic with amines (mono-or poly-amines). The functionalized polyisobutylene provides performance superior detergency in two cycle engines time.

The invention also encompasses the use of other additives in combination with the compositions of this invention. These additives include, for example, agents inhibiting corrosion and oxidation, agents lowering the freezing point, pressure agents extreme, antiwear agents, stabilizers descaling and anti-foaming agents.

Freezer point lowerers are one type particularly useful additives often included in the lubricating oils described here. Use such agents lowering the freezing point in oil-based compositions for improving low temperature properties of base compositions oil is well known in the art. See, for example, page 8 of "Lubricant Additives," by C.V. Smalheer and R. Kennedy Smith (Lezius Hiles Co. publishers, Cleveland, Ohio, 1967).

Examples of agents lowering the freezing point useful are polymethacrylates; polyacrylates; polyacrylamides; condensation products of haloparaffin wax and aromatic compounds; the vinyl carboxylate polymers; and the terpolymers of dialkyl fumarates, vinyl esters of fatty acids and alkyl vinyl ethers. Agents lowering the point useful for the purposes of this invention, the techniques for their preparation and use are described in the patents U.S. (2,387,501; 2,015,748; 2,655,479; 1,815,022; 2,191,498; 2,666,746; 2,721,877; 2,721,878 and 3,250,715).

Anti-foaming agents are used to reduce or prevent the formation of a stable foam. The agents typical defoamers include silicones and organic polymers. Additional compositions defoamers are described in "Foam Control Agents ", by Henty T. Kerner (Noyes Data Corporation, 1976), pages 125-162.

COMPOSITION OF LUBRICATING OIL

The low sulfur detergency additive from this invention is useful for outsourcing greater detergency to an oil composition lubricant for engines. Such an oil composition lubricant includes a majority of an oil base, lubricating viscosity and quantity minority of a low-content detergent additive sulfur. This lubricating composition contains less than 0.2% sulfur.

(a) une partie principale de l'huile de base de viscosité lubrifiante ;

(b) de 5 à 10mM d'un alkylsalicylate de terre alcaline non-soufré ;

(c) de 0,1% à 2% d'un composé de molybdène ; et optionnellement, au moins un de ce qui suit :

(d) une quantité minoritaire d'un solvant non-aromatique;

(e) une quantité minoritaire d'un polyisobutène ;

(f) une quantité minoritaire d'un dispersant sans cendres.

In one embodiment, the lubricating oil composition would contain

(a) a main part of the base oil of lubricating viscosity;

(b) from 5 to 10 mM of an unsulfurized alkaline earth alkylsalicylate;

(c) from 0.1% to 2% of a molybdenum compound; and optionally, at least one of the following:

(d) a minor amount of a non-aromatic solvent;

(e) a minor amount of a polyisobutene;

(f) a minor amount of an ashless dispersant.

The lubricating oil composition of this invention is useful in a lubrication method an air-cooled two-stroke cycle engine. In this method, the lubricant compositions are supplied to the crankcase or added fuel to the engine, and the engine is started.

In an additional embodiment, a lubricating oil composition for engine is produced by mixing the above components. The composition lubricating oil produced by this method can have a slightly different composition from the mixture initial, because the components can interact.

The components can be mixed in any order and can be mixed in the form of combinations of components. For example, alkylsalicyclate and molybdenum compound can be mixed together before being mixed with the other components of the mixed. In the same way, the non-aromatic solvent, polyisobutene, and / or ashless dispersants can be mixed with alkylsalicylate and composed of molybdenum (or the mixture of alkylsalicylate and molybdenum compound) before being mixed with base oil.

ADDITIVE CONCENTRATES

Additive concentrates are also included in the part of this invention. The concentrates of this invention include the compounds or mixtures of compounds of the present invention, preferably with at least minus one other additive, as described above. The concentrates contain sufficient organic diluent to make them easy to handle during transport and storage.

Preferably, the additive concentrate would include 20 to 80% of an organic diluent, the detergent additive to low sulfur content of the present invention and minority amounts of a non-aromatic solvent, polyisobutene, and / or ashless dispersants. The suitable organic thinners that can be used include mineral oil or synthetic oils, as described above in the section called "Oil of Basic Lubricating Viscosity ".

FUEL OILS

As is well known to those specialized in the art of two-engine lubrication oils cycles are often added directly to the fuel to form a mixture of oil and fuel which is then introduced into the engine cylinder. Such fuel oil lubricant mixtures are in the scope of this invention. Such mixtures fuel-lubricant usually contain for a part of oil about 15 to 250 parts of fuel, typically they contain a part of oil for about 25 to 100 parts of fuel.

In some two-cycle engines, the lubricating oil can be directly injected into the combustion with fuel or in fuel just before the fuel enters the fuel chamber combustion. Two cycle lubricants of this invention can be used in this type of motors.

Fuels used in two-cycle engines are well known to those skilled in the art and usually contain a majority portion of a normally liquid fuel such as hydrocarbon petroleum distillate (e.g. petrol for motors as defined by the ASTM specification D-439-73). Such fuels can also contain non-hydrocarbon materials such as alcohols, ethers, organo-nitro compounds and analogues (e.g. methanol, ethanol, diethyl ether, methyl ethyl ether, nitromethane). Fuels liquids derived from vegetable or mineral sources such as corn, alfalfa, shale and coal are also within the scope of this invention.

Examples of such fuel mixtures are combinations of gasoline and ethanol, fuels diesel, diesel fuels and ether, gasoline and nitromethane, etc. We prefer especially petrol, i.e. a mixture of hydrocarbons with an ASTM boiling point of 60 ° C at the 10% distillation point at around 205 ° C at 90% distillation point.

EXAMPLES

The invention will be further illustrated by the examples following, which describe embodiments particularly advantageous of the method. While the examples are provided to illustrate this invention, they are not intended to limit it.

In the following examples, a reference formulation (comparative example C) having a phenate / sulfonate was modified by replacing the phenate / sulphenate with a unsulfurized alkaline earth alkylsalicylate and / or a composed of molybdenum. The reference formulation contained 5.85% succinimide dispersants, but the other comparative examples all contained 4.75% of dispersants succinimide. The results are shown at table I

The detergency index (CEC detergency test at 3 "GD" hours CEC L-079-X-94) was measured for each example. The detergency index is a measure of the engine cleanliness during the test. To the extent of basis, the cleanliness of the candidate oil is compared to that of the reference oil on a percentage. The reference oil is given a clue standard for each test. Specifically, there are approximately eight performance engine areas to which we give a cleanliness rating with different factors weighting. These are then added together to give an overall rating. The notation is then standardized according to the reference oil and we assigns a clue. This index is the number reported and is used to compare the overall performance of oil.

EXAMPLE I

The formulation contained 7mM of earth alkylsalicylate non-sulfur alkaline and 0.25% Molyvan® 855. The formulation contained 4.75% succinimide dispersants.

EXAMPLE II

The formulation contained 7mM of earth alkylsalicylate unsulfurized alkaline and 0.25% oxidesulfide molybdenum. The formulation contained 4.75% dispersants succinimide.

EXAMPLE III

The formulation contained 7mM of earth alkylsalicyiate non-sulfur alkaline but no molybdenum compounds. The formulation contained 4.75% dispersants succinimide.

COMPARATIVE EXAMPLE A

The formulation contained 0.25% Molyvan® 855 but no non-sulfur alkaline earth alkylsalicylate. The formulation contained 4.75% succinimide dispersants.

COMPARATIVE EXAMPLE B

The formulation contained neither unsulfurized alkaline earth alkylsalicylate nor molybdenum compound. This was the reference formulation, with 5.85% succinimide dispersants and 12mM phenate / sulfonate. Example I II III AT B Dispersant 4.75% 4.75% 4.75% 4.75% 5.85% Salicylate 7mM 7mM 7mM - - Composed of Mo 0.25% 0.25% - 0.25% - Detergency index 154 143 141 135 126 S ppm 1,210 1,300 1,220 1,210 1,730

Note that the examples above show that the combination of alkylsalicylate and compound of molybdenum gave higher detergency than one or the other components alone. Note also that examples show that the alkylsalicylate alone or in combination combination with the molybdenum compound gave a higher detergency at lower sulfur level that conventional formulations containing the conventional phenates / sulfonates.

While the present invention has been described in reference to specific embodiments, this request is intended to cover these various changes and substitutions that can be made by those specialized in art without departing from the spirit and the scope of the appended claims.

Claims (10)

Detergency additive suitable for compositions low sulfur lubricants used in air-cooled two-stroke cycle engines comprising an unsulfurized alkaline earth alkylsalicylate. Detergency additive according to claim 1 further comprising a molybdenum compound. Detergency additive according to claim 1 or 2 wherein said alkaline earth alkylsalicylate non-sulfur is calcium alkylsalicylate. Detergency additive according to claim 1, 2, or 3 further comprising an alkylphenol and a alkaline earth alkylphenate, and in which the molar ratio of alkylsalicylate to ring aromatic unique to double-ring alkylsalicylate aromatic in said earth alkylsalicylate non-sulfur alkaline is at least 8: 1. Lubricant composition suitable for air-cooled two-stroke cycle engines comprising: (a) a majority amount of at least one base oil of lubricating viscosity containing less than 0.2% sulfur; (b) a minor amount of a detergency additive according to claim 1, 2, 3 or 4; and (c) optionally at least one of the following: (1) a minor amount of a non-aromatic solvent; (2) a minor amount of a polyisobutene; and (3) a minor amount of an ashless dispersant; where the lubricating composition contains less than 0.2% sulfur. A method of producing a lubricating oil composition suitable for air-cooled two-stroke cycle engines comprising mixing the following components together: (a) a majority amount of at least one base oil of lubricating viscosity comprising less than 0.2% of sulfur; (b) a minor amount of a detergency additive according to claim 1, 2, 3 or 4; and (c) optionally at least one of the following: (1) an amount of a non-aromatic solvent; 2) a minor amount of a polyisobutene; and 3) a minority amount of an ashless dispersant; where the lubricating composition contains less than 0.2% sulfur. Lubricating oil composition suitable for air-cooled two-stroke cycle engines produced by the method according to claim 6. Two-cycle engine lubrication method air-cooled time, including supply of the lubricant composition according to claim 5 or 7 to the crankcase of said motor and the setting operation of said engine. Two-cycle engine lubrication method air-cooled time, including supply of the lubricant composition according to claim 5 or claim 7 to the fuel of said engine and putting the engine into operation. Additive concentrate suitable for air-cooled two-stroke cycle engines in low sulfur applications including: (a) from 20 to 80% of an organic diluent, (b) the detergency additive according to claim 1, 2, 3, 4, and (c) optionally one of the following: (1) a minor amount of a non-aromatic solvent; (2) a minor amount of a polyisobutene; and (3) a minority amount of an ashless dispersant.