JP2022539199A - Lubricating composition for preventing corrosion and/or tribocorrosion of metal parts in engines - Google Patents

Abstract

A lubricating composition for preventing corrosion and/or tribocorrosion of metal parts in an engine. A lubricating composition comprising at least one base oil and from 0.1% to 30% by weight of the phosphorus-containing ester compound of formula (A): TIFF2022539199000014.tif49166, wherein s is 0 or 1, and the X groups independently of each other represent -OR' or R' groups, where R' is preferably a linear or branched group having 1 to 36 carbon atoms. represents a hydrocarbon group or hydrogen, with the proviso that when s is 0, the 3 X groups represent -OR' groups, and when s is 1, at least 2 of the 3 X groups are -OR' A lubricating composition provided that it represents a group. [Selection figure] None

Description

The present invention relates to a novel lubricating composition, especially for engines, and particularly useful for preventing corrosion and/or tribocorrosion of metal parts in engines and especially in two-stroke engines, such as marine two-stroke engines. . The invention also relates to a method for the passivation treatment of metal parts of engines, particularly two-stroke engines such as marine two-stroke engines.

Since 2011, the presence of excessive and even unrestricted corrosion when the engine is operated at very low loads (less than 25% of maximum load) has become noticeable. This excessive corrosion exists due to increasingly harsh operating conditions even with existing modern design engines. Even if the sulfur content of fuels for marine engines is reduced to comply with regulations (SOx emissions) in the near future (2020), corrosion problems will continue to affect many working parts of the engine and even more. The details remain the same for the two-stroke engine.

Combustion of fuel oil causes the formation of _acid gases _, especially sulfur oxides (SO3 formed by the oxidation of SO2), which come into contact with metal parts of the engine. _In the presence of water, SO3 is hydrolyzed to sulfuric _{acid H2SO4} , which is responsible for corrosion of engine parts. Other acids such as nitric acid, compounds with one or more carboxylic acid functional groups, or combinations of these acids can also be responsible for corrosion and/or tribocorrosion of engine parts.

Acid corrosion is in the ring-piston-liner area within the tribological system. On a lubricated engine, in this region the observed friction is of the reciprocating sliding type.

In the case of marine engines, especially marine two-stroke engines, lubricating compositions are divided into two categories: cylinder oil, which ensures lubrication of the entire piston-cylinder, and all moving parts other than the overall piston-cylinder moving parts. It is classified into system oil that guarantees lubrication of

During operation of the engine, cylinder oil spreads over the cylinder forming a thin film of oil between the piston and the wall of the cylinder. This membrane serves the following three purposes.
- ensuring a separation between the two surfaces to avoid adhesive wear;
- to neutralize the sulfuric acid droplets that form in the combustion chamber before they reach the cylinder and cause its wear by corrosion and/or tribocorrosion; to disperse any deposits that may form on

Currently used lubricating compositions for engines, especially marine engines, comprise base oils with the addition of dispersants and overbased detergents. These overbased detergents generally contain a calcium carbonate _CaCO3 core covered by a layer of surfactant. Calcium carbonate reacts with sulfuric acid to form, inter alia, calcium sulfate ( _CaSO4 ). Reduction of sulfuric acid in the medium allows protection of parts against corrosion and/or tribocorrosion.

In order to ensure this protection, the lubricating compositions used must be sufficiently basic (especially to neutralize acids), which means that the detergents contained in these compositions means increasing the amount of

Thus, lubricating compositions currently on the market have base numbers (BN) greater than 70.

However, an increase in the amount of detergents in these lubricating compositions causes surface wear (i.e., abrasive wear) due to grinding of engine metal parts, and especially cylinders of two-stroke engines, such as marine two-stroke engines. leads to an increase in the number of particles of _CaCO3 and _CaSO4 . Moreover, the use of currently available lubricating compositions completely protects metal parts of engines from corrosion and/or tribocorrosion, and especially metal parts of two-cycle engines, from tribocorrosion when the friction is of the reciprocating sliding type. does not protect against

It would therefore be advantageous to provide a lubricating composition that makes it possible to improve the protection against corrosion and/or tribocorrosion of metal parts of engines, particularly two-stroke engines, such as marine two-stroke engines.

It would also be advantageous to provide a lubricating composition that allows for base number reduction.

It is an object of the present invention to provide a lubricating composition which makes it possible to improve the protection against corrosion and/or tribocorrosion of metal parts of engines, typically two-stroke engines, in particular two-stroke marine engines. is.

The present invention more specifically aims at providing a cylinder oil for two-stroke engines, especially marine two-stroke engines.

Another object of the present invention is to provide a lubricating composition having a reduced base number.

Other objects will become more apparent on reading the following description of the invention.

式中、
ｓは０または１であり、また
Ｘ基は、互いに独立して、－ＯＲ’基またはＲ’基を表わし、ここでＲ’は、好ましくは１～３６個の炭素原子を有する、直鎖または分岐の炭化水素基または水素を表わし、ただし、
ｓが０である場合、３つのＸ基が－ＯＲ’基を表わし、そして、
ｓが１である場合、３つのＸ基のうちの少なくとも２つが－ＯＲ’基を表わすことを条件とする。 These objects are met by the present invention which relates to a lubricating composition comprising:
- at least one base oil and - 0.1% to 30%, preferably 0.5% to 20%, preferably 1% to 10% by weight of formula (A), an ester compound containing phosphorus,

During the ceremony,
s is 0 or 1, and the X groups independently of each other represent -OR' or R' groups, where R' preferably has 1 to 36 carbon atoms, linear or represents a branched hydrocarbon group or hydrogen, provided that
when s is 0, the three X groups represent -OR' groups, and
provided that when s is 1, at least two of the three X groups represent -OR' groups.

Preferably R' represents a straight or branched alkyl group containing 1 to 36 carbon atoms, preferably 2 to 30 carbon atoms, preferably 4 to 24 carbon atoms, or R' represents a straight-chain or branched alkenyl group containing 2 to 36 carbon atoms, preferably 2 to 30 carbon atoms, preferably 4 to 24 carbon atoms.

式中、
－ 同一のまたは異なるものであるＲ^１およびＲ^２は独立して、１～３６個の炭素原子、好適には２～３０個の炭素原子、有利には４～２４個の炭素原子を含む、直鎖または分岐アルキル基を表わすか、あるいは同一のまたは異なるものであるＲ^１およびＲ^２は独立して、２～３６個の炭素原子、好適には２～３０個の炭素原子、有利には４～２４個の炭素原子を含む、直鎖または分岐アルケニル基を表わし、そして
－ Ｒ^３は、水素またはヒドロキシル基（ＯＨ）を表わす。 Suitably these objects are met by the present invention, which relates to a lubricating composition comprising:
- at least one base oil and - 0.1% to 30%, preferably 0.5% to 20%, preferably 1% to 10% by weight of formula (B), compounds of phosphorus-containing esters,

During the ceremony,
- identical or different R ¹ and R ² independently contain 1 to 36 carbon atoms, preferably 2 to 30 carbon atoms, preferably 4 to 24 carbon atoms, R ¹ and R ² , which represent linear or branched alkyl groups or are the same or different, independently have 2 to 36 carbon atoms, preferably 2 to 30 carbon atoms, preferably Represents a straight or branched alkenyl group containing 4 to 24 carbon atoms, and —R ³ represents hydrogen or a hydroxyl group (OH).

Preferably, alkenyl groups (R ¹ and/or R ² ) according to the invention contain at least one double bond. Preferably, said double bond is located at C-9, C-10 of the alkenyl group in relation to the functional group of the phosphorus-containing ester.

Preferably, the R ¹ , R ² or R ³ groups do not contain sulfur or nitrogen atoms.

According to the invention, a hydrocarbon group is a saturated, partially or fully linear or branched, unsaturated.

According to one particular embodiment of the invention, the base oil contained in the lubricating composition is selected among oils of mineral, synthetic or plant origin, and mixtures thereof.

Mineral or synthetic oils generally used in this application belong to one of the classes defined in the API classification as summarized in the table below.

The first group of mineral oils are the distillates of selected naphthenic or paraffinic crude oils followed by distillates of these by processes such as extraction with solvents, dewaxing with solvents or catalysts, hydrotreating or hydrogenation. It can be obtained by purification.

Group 2 and 3 oils are obtained by a combination of among the more severe refining processes such as hydrotreating, hydrocracking, hydrogenation and catalytic dewaxing.

Examples of Group 4 or 5 synthetic base oils include polyalphaolefins, polybutenes, polyisobutenes, alkylbenzenes.

These base oils can be used alone or in a mixed form. Mineral oils may be combined with synthetic oils.

Cylinder oils for marine two-stroke diesel engines have a viscosity grade of SAE-40 to SAE-60, typically SAE-50 which is equivalent to a 100° C. kinematic viscosity of 16.3 to 21.9 mm ² /s. .

A grade 40 oil has a 100° C. kinematic viscosity of 12.5-16.3 mm ² /s.

A grade 50 oil has a 100° C. kinematic viscosity of 16.3-21.9 mm ² /s.

A grade 60 oil has a 100° C. kinematic viscosity of 21.9-26.1 mm ² /s.

Depending on the commercial application, cylinder oils for marine two-stroke diesel engines should be formulated to have a 100° C. kinematic viscosity of 18-21.5, preferably 19-21.5 mm ² /s. is preferred.

This viscosity can be obtained, for example, by blending base oils with additives, including Group 1 mineral base oils, such as Solvent Neutral base oils (eg, 500SN or 600SN) and Brightstock. Any other combination of mineral, synthetic or vegetable derived base oils having a viscosity compatible with an SAE-50 rating when mixed with additives can be used.

Typically, conventional formulations of cylinder lubricants for marine low-speed two-stroke diesel engines are of SAE 40 to SAE 60 grade, preferably SAE 50 grade (according to SAE J300 standard), e.g. These have been adapted for use in group class marine engines, i.e. by processes such as cracking distillation of selected crudes followed by solvent extraction, solvent or catalytic dewaxing, hydrotreating or hydrogenation. Contains at least 50% by weight of a mineral-derived and/or synthetic lubricating base oil obtained by distillate refining. Its viscosity index (VI) is 80-120, its sulfur content is greater than 0.03% and its saturates content is less than 90%.

Advantageously, the lubricating composition according to the invention comprises at least 50% by weight of the base oil or oils relative to the total weight of the composition.

More advantageously, the lubricating composition according to the invention comprises at least 60% by weight, even at least 70% by weight, of the base oil or oils relative to the total weight of the composition.

More particularly advantageously, the lubricating composition according to the invention comprises 60-99.9% by weight of base oil, preferably 70-98% by weight of base oil, relative to the total weight of the composition.

Preferably, the lubricating composition according to the invention further comprises at least one additive selected from detergents, dispersants and mixtures thereof.

Detergents used in the lubricating compositions of the present invention are well known to those skilled in the art.

Detergents commonly used in formulating lubricating compositions in accordance with the present invention are anionic compounds containing a long lipophilic hydrocarbon chain and a hydrophilic head group. Relevant cations are metal cations of alkali metals or alkaline earth metals.

Detergents are preferably selected among alkali metal or alkaline earth metal salts of carboxylic acids, sulphonic acids, salicylic acids, naphthenic acids and phenate salts.

Alkali metals and alkaline earth metals are preferably calcium, magnesium, sodium or barium.

These metal salts may contain metals in near stoichiometric amounts. In this case, we refer to non-overbased or "neutral" detergents, but they also contribute some basicity. These "neutral" detergents typically have a BN of less than 150 mg KOH/g, or less than 100 mg KOH/g, or even less than 80 mg KOH/g, measured according to ASTM D2896.

This type of detergent, called neutral, can partially contribute to the BN of the lubricant according to the invention. By way of example, neutral detergents of the carboxylate, sulfonate, salicylate, phenate, naphthenate type of alkali metals and alkaline earth metals such as calcium, sodium, magnesium, barium are utilized.

If the metal is in excess (greater than the stoichiometric amount), the result is a detergent called overbased. Their BN is high, eg above 150 mg KOH/g, typically 200-700 mg KOH/g, typically 250-450 mg/KOH/g.

Excess metals that impart overbasing properties to the detergent are in the form of oil-insoluble metal salts such as carbonates, hydroxides, oxalates, acetates, glutamates, preferably carbonates.

In the same overbased detergent, the metals of these insoluble salts may be the same as in the oil-soluble detergent, or they may be different. These are preferably selected among calcium, magnesium, sodium or barium.

Overbased detergents thus take the form of micelles composed of insoluble metal salts which are maintained in suspension in the lubricating composition by the detergent in the form of oil-soluble metal salts.

Overbased detergents containing a single type of detergent-soluble metal salt are generally named for the nature of the hydrophobic chain of the detergent.

These overbased detergents are therefore of the carboxylate-type, phenate-type, salicylate-type, sulfonate-type, naphthenate-type, depending on whether the detergent is a carboxylate, phenate, salicylate, sulfonate or naphthenate, respectively. is called that of

Overbased detergents are said to be of mixed type when the micelles contain multiple types of detergents that differ from each other by the nature of their hydrophobic chains.

For use in the lubricating composition according to the present invention, the oil-soluble metal salts are preferably calcium, magnesium, sodium or barium phenates, sulfonates and/or salicylates mixed detergents, salicylates, sulfonates, phenates. , and carboxylate.

Insoluble metal salts that provide overbasing properties are alkali metal and alkaline earth metal carbonates, preferably calcium carbonate.

Preferably, the detergents used in the lubricating compositions of the present invention are overbased with calcium carbonate selected from among carboxylates, phenates, sulfonates, salicylates, and phenate-sulfonate-salicylate mixed detergents. It is a cleaning agent that has been

Advantageously, the lubricating composition according to the invention comprises 3 to 40% by weight, preferably 5% to 30% by weight, preferably 10% to 25% by weight, relative to the total weight of the lubricating composition. may include one or more detergents of

Dispersants are well known additives used in the formulation of lubricating compositions, particularly for applications in the marine sector. Its primary role is to keep in suspension particles that are originally present in the lubricating composition or that appear in the lubricating composition during use in the engine. These dispersants prevent their aggregation by acting on steric hindrance. These dispersants can also have a synergistic effect on neutralization.

Dispersants used as lubricant additives in the present invention comprise a polar group attached to a relatively long hydrocarbon chain, generally containing 50 to 400 carbon atoms. Polar groups typically include at least one nitrogen or oxygen element.

Compounds derived from succinic acid are dispersants that are particularly used as lubricity additives. In particular, succinimides obtained by condensation of succinic anhydrides and amines, succinic acid esters obtained by condensation of succinic anhydrides with alcohols or polyols are used.

These compounds can then be treated with a variety of compounds, particularly those containing sulfur, oxygen, formaldehyde, carboxylic acids, and boron or zinc to produce, for example, borated succinimides or zinc-blocked succinimides.

Mannich bases obtained by polycondensation of alkyl-substituted phenols, formaldehyde and primary or secondary amines are likewise compounds used as dispersants in lubricants.

Preferably, the dispersant according to the invention is selected among succinimides, such as polyisobutylene bis-succinimide, optionally borated or zinc blocked.

Advantageously, the lubricating composition according to the invention contains 0.01 to 10% by weight, preferably 0.1% to 5% by weight, advantageously 0.5% by weight, relative to the total weight of the lubricating composition. It may contain from weight % to 3 weight % of dispersant(s).

The lubricating composition may further comprise at least one antiwear additive.

Preferably, the antiwear additive is zinc dithiophosphate or ZDDP. Also included in this category are various compounds containing phosphorus, sulfur, nitrogen, chlorine and boron.

Although there are a variety of antiwear additives, the most commonly used category is metal alkylthiophosphates, specifically zinc alkylthiophosphates, and more specifically zinc dialkyldithiophosphates, or ZDDP, which are phosphorous-sulfur. category of additives, including

Amine phosphates, polysulfides, particularly sulfur-containing olefins, are also commonly used antiwear additives.

Also commonly found in lubricating compositions are antiwear and extreme pressure additives of the nitrogen- and sulfur-containing type, such as, for example, metal dithiocarbamates, particularly molybdenum dithiocarbamates. Esters of glycerol are also antiwear additives. Examples include mono-, di- and trioleates, monopalmitate and monomyristate.

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 50% to 96.9% by weight, preferably 60% to 95%, more preferably 70% to 90% by weight of the base oil(s),
- 0.1% to 30% by weight, preferably 0.5% to 20%, more preferably 1% to 10% by weight of one or more phosphorus-containing ester compounds of formula (A), and - 3% to 40% by weight, preferably 5% to 30%, more preferably 10% to 25% by weight of detergent(s), and - optionally 0.01% to 10% by weight, preferably is 0.1 to 5% by weight, more preferably 0.5% to 3% by weight of dispersant(s).

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 50% to 96.9% by weight, preferably 60% to 95%, more preferably 70% to 90% by weight of the base oil(s),
- 0.1% to 30% by weight, preferably 0.5% to 20%, more preferably 1% to 10% by weight of one or more phosphorus-containing ester compounds of formula (B), and - 3% to 40% by weight, preferably 5% to 30%, more preferably 10% to 25% by weight of detergent(s), and - optionally 0.01% to 10% by weight, preferably is 0.1 to 5% by weight, more preferably 0.5% to 3% by weight of dispersant(s).

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 60 to 99 wt%, preferably 60 to 95 wt%, more preferably 70 to 90 wt% of the base oil(s),
- 0.1 to 30% by weight, preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight of one or more phosphorus-containing ester compounds of formula (A); 01-10% by weight, preferably 0.1-5% by weight, more preferably 0.5-3% by weight of a dispersant or agents, and optionally 3-40% by weight, preferably 5-30% by weight. % by weight, more preferably 10-25% by weight of detergent(s).

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 60 to 99 wt%, preferably 60 to 95 wt%, more preferably 70 to 90 wt% of the base oil(s),
- 0.1 to 30% by weight, preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight of one or more phosphorus-containing ester compounds of formula (B); 01-10% by weight, preferably 0.1-5% by weight, more preferably 0.5-3% by weight of a dispersant or agents, and optionally 3-40% by weight, preferably 5-30% by weight. % by weight, more preferably 10-25% by weight of detergent(s).

The lubricating compositions can be any type of functional additive adapted for their use, e.g. polar polymers such as polymethylsiloxanes, polyacrylates, antifoam additives, e.g. phenolic or amino antioxidant additives, and/or antirust additives, such as organometallic compounds or thiadiazoles, may also be included. These are known to those skilled in the art.

According to one embodiment of the invention, the compound of formula (A) is the following compound (I):

According to one embodiment of the invention, the compound of formula (B) is the following compound (I):

According to another embodiment of the invention, the compound of formula (A) is compound (II) below:

According to another embodiment of the invention, the compound of formula (B) is compound (II) below:

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 50 to 96.9 wt%, preferably 60 to 95 wt%, more preferably 70 to 90 wt% of the base oil or oils,
- 0.1 to 30% by weight, preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight of at least one compound of formula (I) or formula (II) as defined above , one or more phosphorus-containing ester compounds, and 3-40% by weight, preferably 5-30% by weight, more preferably 10-25% by weight of an overbased detergent of the phenate or sulfonate type at least one or more detergents, and optionally 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight of one or more dispersants. .

According to one particular embodiment, the lubricating composition comprises, relative to the total weight of the lubricating composition:
- 60 to 99 wt%, preferably 60 to 95 wt%, more preferably 70 to 90 wt% of the base oil(s),
- 0.1-30% by weight, preferably 0.5-20% by weight, more preferably 1-10% by weight, of at least one compound of formula (I) or formula (II) as defined above , one or more phosphorus-containing ester compounds, and - 0.01 to 10% by weight, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight of succinimide and optionally 3 to 40% by weight, preferably 5 to 30% by weight, more preferably 10 to 25% by weight of one or more detergents.

The invention likewise relates to the use of the lubricating composition according to the invention for the lubrication of at least one metal part of an engine such as a two-stroke engine, in particular a marine two-stroke engine.

Preferably, the use of the lubricating composition according to the invention makes it possible to prevent and/or reduce corrosion and/or tribocorrosion of said metal parts of said engine.

The invention likewise relates to a method of lubricating at least one metal part of an engine, such as a two-stroke engine, in particular a marine two-stroke engine, comprising contacting said part of the engine with a lubricating composition according to the invention.

The present invention also relates to a lubricating oil comprising at least one base oil for preventing and/or reducing corrosion and/or tribocorrosion of at least one metal part of an engine, such as a two-stroke engine, particularly a marine two-stroke engine. It also relates to the use of the compounds of formula (A) according to the invention in compositions.

The present invention also relates to a lubricating oil comprising at least one base oil for preventing and/or reducing corrosion and/or tribocorrosion of at least one metal part of an engine, such as a two-stroke engine, particularly a marine two-stroke engine. It also relates to the use of the compounds of formula (B) according to the invention in compositions.

The present invention also relates to the prevention of corrosion and/or tribocorrosion of at least one metal part of an engine, such as a two-stroke engine, in particular a marine two-stroke engine, comprising lubricating said metal part with a lubricating composition according to the invention. It also relates to prevention and/or mitigation methods.

The invention likewise relates to the use of the lubricating composition according to the invention for the passivation treatment of at least one metal part of an engine such as a two-stroke engine, in particular a marine two-stroke engine.

The invention likewise relates to a method of passivating at least one metal part of an engine, comprising the step of contacting at least one of said metal part with a lubricating composition according to the invention.

The invention likewise relates to the invention in a lubricating composition comprising at least one base oil for the passivation treatment of at least one metal part of an engine such as a two-stroke engine, in particular a marine two-stroke engine. It also relates to the use of compounds of formula (A).

The invention likewise relates to the invention in a lubricating composition comprising at least one base oil for the passivation treatment of at least one metal part of an engine such as a two-stroke engine, in particular a marine two-stroke engine. It also relates to the use of compounds of formula (B).

Preferably, the metal parts according to the invention are cylinders or pistons.

Advantageously, the metal parts are made of cast iron.

Preferably, the engine according to the invention is a two-stroke engine. Preferably, the engine is a marine two-stroke engine.

Preferably, the engine is a heavy oil consuming engine. "Heavy oil" in the sense of the present invention is the heavy fraction, optionally with additives, derived from the cracking distillation of petroleum.

In the sense of the invention, "corrosion" means alteration of a material, preferably a metallic material, by chemical reaction with an oxidizing agent. Preferably, this oxidizing agent is an acid. Preferably, this acid is sulfuric _{acid H2SO4} .

In the sense of the present invention, "tribocorrosion" means a process that leads to deterioration and wear of metallic materials by the combined action of corrosion and friction as defined above.

Advantageously, the compounds of formula (A) as defined in the present invention are used in cylinder lubricating compositions to reduce acid tribolysis on the cylinders and pistons of two-stroke engines, such as marine two-stroke engines. Reduce corrosion.

More advantageously, the compounds of formula (B) as defined in the present invention are used in cylinder lubricating compositions to prevent acid-induced damage on the cylinders and pistons of two-stroke engines, such as marine two-stroke engines. Reduce tribocorrosion.

1 represents the depth profile of a cast iron plank obtained after tribological tests conducted in the presence of the lubricating composition CL2 according to the invention and the comparative composition CC1.

The invention will now be illustrated using non-limiting examples.

Example 1 Lubricating Compositions The compositions of Table 2 (CL: lubricating composition according to the invention, CC: comparative lubricating composition) were mixed with dispersants and/or detergents and additives in a base oil at 60°C. Prepared by mixing.

Example 2 Results of Wear Depth Tests Tribological tests were performed on a reciprocating tribometer Biceri using a steel bar (EN31) with a diameter of 6 mm and a radius of curvature of 50 mm and cast iron thicknesses polished with 800 grit SiC abrasive paper. plate (FT25). A steel bar was similarly ground to obtain a roughness Ra of 50-100 nm. Additionally, the areas of the cast iron slab outside the friction area were completely covered with resin. This resin is removed at the end of the test. In that way, the area completely covered with resin does not corrode during the test and serves as a measure for measuring the depth of wear scars due to corrosion phenomena.

Prior to each test, the lubricating composition is heated to 100° C. and contacted with a room temperature 5M (27% by weight) sulfuric acid solution using a “T” configuration. The lubricating composition was conveyed through the main conveying pipe and the acid solution was fed through the conveying pipe perpendicular to the main conveying pipe.

The conditions for these tests are as follows.
- Temperature: 100°C
- Pressure: 0.67 GPa
- Velocity: 0.02m/s
- trace length: 5 mm;
- Duration: 6 hours

At the end of each test, corrosion products were removed using ethylenediaminetetraacetic acid (EDTA) solution and wear of the cast iron slab was analyzed by white light interferometry, which was caused by corrosion and/or tribocorrosion. It made it possible to obtain a 3D profile of the wear scar.

These 3D profiles make it possible to obtain the depth profile of the wear scar. FIG. 1 represents the depth profile of a cast iron slab obtained after tribological tests as described above derived in the presence of the lubricating composition CL2 according to the invention and the comparative composition CC1. there is

The results of these tests show that in the absence of additives, cast iron slabs corrode in areas not in contact with steel bars (out-of-contact areas), and wear due to tribocorrosion similarly It is shown to be observed at the contacting regions. The presence of additives improves protection against corrosion and tribocorrosion. Indeed, without intending to be bound by any theory, the additive aids in the neutralization of acid droplets by the detergent by forming a physical barrier between the surface of the metal part and the oil of the lubricating composition. , which prevents corrosion phenomena.

Lubricating compositions according to the present invention, more specifically compositions containing compounds of formula (I) or (II) (CL1 and CL2), are effective in reducing cast iron plate corrosion (out-of-contact area) and tribocorrosion ( contact area) and at the same time effectively protect against

Claims (10)

- at least one base oil and - 0.1% to 30% by weight of the phosphorus-containing ester compound of formula (A),

A lubricating composition comprising
wherein s is 0 or 1, and the X groups independently represent a -OR' group or an R' group, where R' preferably has 1 to 36 carbon atoms, represents a chain or branched hydrocarbon group or hydrogen, provided that
when s is 0, the three X groups represent -OR' groups, and
A lubricating composition provided that when s is 1, at least two of the three X groups represent -OR' groups. - at least one base oil, and - 0.1% to 30% by weight of the phosphorus-containing ester compound of formula (B),

including
The compound is
- R ¹ and R ² , which are the same or different, independently represent a linear or branched alkyl group containing from 1 to 36 carbon atoms, or R ¹ and R, which are the same or different ² independently represents a straight or branched alkenyl group containing from 2 to 36 carbon atoms, and —R ³ represents hydrogen or a hydroxyl group;
The lubricating composition of claim 1, defined as: 3. A composition according to claim 1 or 2, further comprising at least one additive selected from detergents, dispersants and mixtures thereof. - the amount of detergent, relative to the total weight of the lubricating composition, has a value of 3% to 40%, preferably 5% to 30%, preferably 10% to 25% by weight; and/or - the amount of dispersant, relative to the total weight of the lubricating composition, is between 0.01% and 10% by weight, preferably between 0.1% and 5% by weight, preferably 0 takes a value between .5% and 3% by weight,
4. The composition of claim 3. 5. The detergent of claim 3 or 4, wherein the detergent is a detergent overbased with calcium carbonate selected from among carboxylates, phenates, sulfonates, salicylates and mixed phenate-sulfonate-salicylate detergents. The described composition. The compound of formula (A) or the compound of formula (B) has the following formula

6. A composition according to any one of claims 1 to 5, corresponding to a compound of formula (I), as defined by: The compound of formula (A) or the compound of formula (B) has the following formula

6. A composition according to any one of claims 1 to 5, corresponding to a compound of formula (II), defined by: A lubricating composition comprising at least one base oil for preventing and/or reducing corrosion and/or tribocorrosion of at least one metal part of an engine, in particular a two-stroke engine, such as a marine two-stroke engine. Use of compounds of formula (A) or formula (B) as defined in 1, 2, 6 or 7. Composition according to any one of claims 1 to 7 for the prevention and/or mitigation of corrosion and/or tribocorrosion of at least one metal part of an engine, in particular a two-stroke engine, for example a two-stroke marine engine. use of things. A process for the passivation treatment of at least one metal part of an engine, in particular a two-stroke engine, for example a two-stroke marine engine, said metal part being treated with a lubricating composition according to any one of claims 1 to 7. A method comprising at least one step of contacting.

Images