KR20130071384A - Marine engine lubrication - Google Patents

Abstract

PURPOSE: A lubricating method of an engine for a ship is provided to reduce generation of a precipitation in a centrifuge of a diesel engine. CONSTITUTION: A lubricant composition comprises 1-25 wt% of a polyisobutylene. The polyisobutylene has a number average molecular weight of 1,300-2,225, a kinematic viscosity at 100 v of 50-50,000 mm^2/sec. The lubricant composition includes 0.5 wt% or less of brightstock. The lubricant composition does not materially contain brightstock.

Description

Marine engine lubrication method {MARINE ENGINE LUBRICATION}

The present invention relates to a method for reducing deposit formation in centrifuge systems of trunk piston diesel engines.

Trunk piston diesel engines are used in marine, power generation and rail towing applications and may have rated speeds of 300 to 1000 rpm. In trunk piston diesel engines, a single lubricant composition is used for crankcase and cylinder lubrication. All major drive components of the engine, ie the main and crankpin bearings, camshafts and valve gears, are lubricated by a pumping circulation system. The cylinder liner is partially splashed by lubrication, in part by oil from the circulation system reaching the cylinder wall through holes in the piston skirt via connecting rods and piston pins. Lubricated.

Trunk piston diesel engines use centrifuge systems to remove contaminants such as, for example, soot or water from lubricant compositions. Centrifuge systems rely on the use of encapsulation media heavier than lubricant. Inclusion medium is generally water. As the lubricant composition passes through the centrifuge system, the composition is in contact with water. Therefore, the lubricant should be able to block the water and remain stable in the presence of water. If the lubricant is unable to block the water, water accumulates in the lubricant to produce emulsified nuclei, which causes deposit buildup in the centrifuge system and prevents the centrifuge system from operating properly. Centrifuge systems normally operate at temperatures below 100 ° C, for example below 95 ° C, for example about 90 ° C.

Traditional trunk piston diesel engine lubricant compositions have a total base number of 30 to 40. However, recent developments of trunk piston diesel engines with very low oil consumption have provided a lubricant formula that increases the total base to, for example, 50 to 60. Unfortunately, this increase in total base adversely affects the ability of the lubricant composition to block any contaminants with the encapsulation medium used in the centrifuge system, resulting in deposit accumulation in the centrifuge system.

It is an object of the present invention to provide a reduction in deposit formation in centrifuge systems of trunk piston diesel engines.

US-A-2008 / 0287329 A1 ("'329") describes lubricant oil for marine four-stroke engines comprising 1 to 20% by weight of one or more polyisobutylenes. '329 mentions that the viscosity increase of the lubricant oil is delayed. However, '329 does not address the above-mentioned deposit generation problem in centrifuges of trunk piston engines.

It has now been found that polyisobutylene additives in trunk piston engine oil lubricants can solve the deposit formation.

Accordingly, the present invention relates to an additive constituting 1 to 25% by mass of a trunk piston diesel engine lubricant composition, which has a number average molecular weight in the range of 400 to 8000, for example in the range of 1,300 to 2,225, and 50 to 50,000 mm ² / sec. Centrifugation of the engine when the lubricant composition lubricates the engine during operation of a trunk piston diesel engine, for example of polyisobutylene having a kinematic viscosity at 100 ° C. in the range of 630 to 2500 mm ² / sec. Provides use for reducing deposit production in separators.

Preferably, the trunk piston diesel engine lubricant composition contains little or no brightstock. Preferably, the trunk piston diesel engine lubricant composition is substantially free of brightstock. Even more preferably, the trunk piston diesel engine lubricant composition does not contain brightstock.

In this specification, the following words and expressions, when used, have the meanings indicated below:

"Active ingredient" or "(a.i.)" refers to an additive material that is not a diluent or solvent;

"Comprising" or any cognate word specifies the presence of a feature, step, or integer or component mentioned, but does not exclude the presence or addition of one or more other features, steps, integers, components, or groups thereof; “Consist of” or “consist of” or cognate language may be included in “comprises” or cognates, where “consisting of” includes material that does not materially affect the properties of the composition to which it is applied. Allow;

"Major amount" means at least 50% by mass of the composition;

"Minor amount" means less than 50% by mass of the composition;

"TBN" means total base as measured by ASTM D2896.

Also used herein, when used:

“Calcium content” is as measured by ASTM 4951;

"Phosphorus content" is as measured by ASTM D5185;

"Sulphated ash content" is as measured by ASTM D874;

"Sulfur content" is as measured by ASTM D2622;

"KV100" is the kinematic viscosity at 100 ° C as measured in ASTM D445.

In addition, it will be appreciated that the various components used, which are essential, optimal and customary, can react under blending, storage or use conditions, and the present invention also provides the products obtained or obtained as a result of any of the above reactions.

It is also understood that the upper and lower limits of any amount, range, and ratio shown herein can be combined independently.

Features of the present invention will now be discussed in more detail below.

Oil with a lubricating viscosity

The lubricant composition contains an oil having a major amount of lubricating viscosity. Such lubricants may range in viscosity from light distillate mineral oils to heavy lubricants. In general, the viscosity of the oil ranges from 2 to 40 mm ² / sec, for example 3 to 15 mm ² / sec, as measured at 100 ° C., and a viscosity index of 80 to 100, for example 90 to 95 Has The lubricating oil may comprise at least 60 mass%, typically at least 70 mass% of the composition.

The oil may comprise 'brightstock' which refers to a base oil which is a solvent-extracted de-asphalt product, typically from a vacuum residue having a kinematic viscosity at 100 ° C. of 28 to 36 mm ² s ⁻¹ . have. However, it is preferred that little or no brightstock is included, for example less than 5, 4, 3, 2 or 1% by mass, based on the mass of the composition. Brightstock may be completely or substantially absent.

Natural oils include animal and vegetable oils (eg castor oil, lard oil); Liquefied petroleum, and hydrogenated, solvent-treated or acid-treated mineral oils of the paraffin, naphthenic and mixed paraffin-naphthenic types. Oils with a lubricating viscosity derived from coal or shale are also used as useful base oils.

Synthetic lubricants include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g. polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly (1- Hexene), poly (1-octene), poly (1-decene)); Alkylbenzenes (eg dodecylbenzene, tetradecylbenzene, dinonylbenzene, di (2-ethylhexyl) benzene); Polyphenyls (eg, biphenyls, terphenyls, alkylated polyphenols); And alkylated diphenyl ethers and alkylated diphenyl sulfides, and derivatives, analogs and homologs thereof.

Alkylene oxide polymers and interpolymers, and derivatives thereof whose terminal hydroxyl groups are modified by esterification, etherification, and the like, form another class of known synthetic lubricants. These are polyoxyalkylene polymers prepared by polymerization of ethylene oxide or propylene oxide, and alkyl and aryl ethers of polyoxyalkylene polymers (eg, methyl-polyiso-propylene glycol ethers having a molecular weight of 1000, or 1000 Diphenyl ether of poly-ethylene glycol having a molecular weight of from 1500 to 1500); And mono- and polycarboxylic acid esters thereof such as acetic acid ester of tetraethylene glycol, mixed C ₃ -C ₈ fatty acid esters and C ₁₃ oxoacid diesters.

Another suitable class of synthetic lubricants include dicarboxylic acids (eg, phthalic acid, succinic acid, alkyl succinic acid and alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid). , Esters of alkylmalonic acid, alkenyl malonic acid) and various alcohols (e.g. butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol) do. Specific examples of such esters include dibutyl adipate, di (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, Complexes produced by reaction of didecyl phthalate, diecosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, and 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid Ester is included.

Esters useful as synthetic oils are also esters prepared from C ₅ to C ₁₂ monocarboxylic acids and polyols, and polyol esters such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripenta Erythritol is included.

Silicone-based oils such as polyalkyl-, polyaryl-, polyalkoxy- or polyaryloxysilicone oils and silicate oils form another useful class of synthetic lubricants; Examples of the oil include tetraethyl silicate, tetraisopropyl silicate, tetra- (2-ethylhexyl) silicate, tetra- (4-methyl-2-ethylhexyl) silicate, , Hexa- (4-methyl-2-ethylhexyl) disiloxane, poly (methyl) siloxane and poly (methylphenyl) siloxane. Other synthetic lubricants include liquid esters of phosphorus-containing acids (eg, tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid) and polymeric tetrahydrofuran.

Unrefined, refined and re-refined oils can be used in the lubricants of the present invention. Crude oils are those obtained directly from natural or synthetic sources without further purification. For example, shale oil obtained directly from a retorting operation; Petroleum obtained directly from distillation; Or ester oils obtained directly from esterification and used without further treatment are crude oils.

Polyisobutylene

The polyisobutylene additive is 1 to 20% by mass, or 1 to 15% by mass, for example 1 to 10% by mass, for example 1 to 6% by mass, for example 1 to 5% by mass, for example For example, it may be present in a ratio of 1 to 4 mass%.

As mentioned above, polyisobutylene has a number average molecular weight in the range of 400 to 8,000, for example 1,300 to 2,225. Among other ranges that may be used are the following: 900 to 3,000, 1,000 to 8,000, 1,500 to 6,000, and 2,000 to 5,000, and also the lower limit of 500.

In addition, polyisobutylene has a kinematic viscosity at 100 ° C. in the range of 50 to 50,000 mm ² / sec, for example 630 to 2500 mm ² / sec. Among other ranges that may be used are the following: 2,000 to 6,000 mm ² / sec, 2,000 to 5,000 mm ² / sec and 3,000 to 4,500 mm ² / sec. Polyisobutylene also includes mixtures of several polyisobutylenes which may be synthesized separately and may have a molecular weight outside the ranges indicated above, provided that the mixture of various polyisobutylenes has a molecular weight within that range.

Polyisobutylene is commercially available.

Co-additive

One or more of the following may also be required in the composition.

Detergent

Detergents are additives that reduce the formation of deposits in the engine, such as hot varnish and lacquer deposits; The detergent has acid-neutralizing properties and can hold the pulverulent solid as a suspension. The detergent is a metal salt of an acidic organic compound and is based on a metal "soap", sometimes called a surfactant.

Detergents include polar heads with long hydrophobic tails. Excess metal compound, such as an oxide or hydroxide, is reacted with an acidic gas such as carbon dioxide to provide an overbased detergent comprising a neutralizing detergent as an outer layer of a metal base (eg carbonate) micelle. The main amount of metal base is thereby included.

The detergent is preferably an oil-soluble or oil-dispersible calcium of an alkali metal or alkaline earth metal additive, for example a surfactant selected from phenol, sulfonic acid, carboxylic acid, salicylic acid and naphthenic acid, Magnesium, sodium or barium salts, wherein overbased salts are used in oil-insoluble salts of metals, such as carbonates, basic carbonates, acetates, formates, hydroxides or oxalates, which are stabilized by oil-soluble salts of the surfactant. Provided by The metal of the oil-soluble surfactant salt may be the same as or different from the metal of the oil-insoluble salt. Preferably, the metal, whether oil soluble salt or oil-insoluble salt, is calcium.

The TBN of the detergent, when measured by ASTM D2896, may be low, ie, less than 50 mg KOH / g, medium, ie, 50 to 150 mg KOH / g, or high, ie 150 mg KOH / g or more. Preferably, the TBN is medium or high, ie at least 50 TBN. More preferably, TBN is 60 or more, more preferably 100 or more, more preferably 150 or more, and 500 or less, for example, 350 mg KOH / g or less, as measured by ASTM D2896.

The surfactant of the surfactant system of the overbased detergent preferably contains one or more hydrocarbyl groups, for example as substituents on the aromatic ring. As used herein, the term "hydrocarbyl" refers to a group of other atoms or groups in which the associated group consists mainly of hydrogen and carbon atoms and is bonded by carbon atoms to the rest of the molecule but is insufficient to substantially impair the hydrocarbon properties of the group. It does not exclude the existence. Advantageously, the hydrocarbyl groups in the surfactants for use according to the invention are aliphatic groups which can be linear or branched, preferably alkyl or alkylene groups, especially alkyl groups. The total number of carbon atoms in the surfactant should be at least sufficient to provide the desired utility.

The phenols for use in preparing the detergents may be non-sulfurized or preferably sulfurized. In addition, the term “phenol” as used herein refers to phenols containing more than one hydroxyl group (eg, alkyl catechol) or fused aromatic ring (eg, alkyl naphthol), and by chemical reactions. Modified phenols such as alkylene-crosslinked phenols and Mannich base-condensed phenols; And salicidein-type phenols (produced by the reaction of phenols with aldehydes under basic conditions).

Preferred phenols can be derived from the formula:

In the above, R represents a hydrocarbyl group, and y represents 1 to 4. If y is greater than 1, the hydrocarbyl groups may be the same or different.

Phenols are often used in sulfided form. Sulfated hydrocarbyl phenols are typically represented by the formula:

In the above, x is generally 1-4. In some cases, more than two phenol molecules may be linked by S _x crosslinking.

In the above formula, the hydrocarbyl group represented by R is advantageously an alkyl group, which alkyl group advantageously contains 5 to 100, preferably 5 to 40, in particular 9 to 12 carbon atoms, and in all R groups The average number of carbon atoms is at least 9 to ensure proper solubility in oil. Preferred alkyl groups are nonyl (tripropylene) groups.

In the discussion that follows, hydrocarbyl-substituted phenols are referred to as alkyl phenols for convenience.

The sulfiding agent for use in preparing the sulfided phenol or phenate can be any compound or element that introduces a-(S) _x -bridging group between alkyl phenol monomer groups, where x is generally from 1 to about 4. Thus, the reaction can be carried out using elemental sulfur or a halide thereof, for example sulfur dichloride or more preferably sulfur monochloride. When elemental sulfur is used, the sulfidation reaction can be carried out by heating the alkyl phenol compound at 50 to 250 ° C, preferably at least 100 ° C. The use of elemental sulfur typically provides a mixture of crosslinking groups-(S) _x -as described above. When using sulfur halides, the sulfidation reaction can be carried out by treating alkyl phenols at -10 to 120 ° C, preferably at least 60 ° C. The reaction can be carried out in the presence of a suitable diluent. Diluents advantageously comprise substantially inert organic diluents such as mineral oil or alkanes. In any case, the reaction is carried out for a time sufficient to carry out the actual reaction. In general, it is preferred to use from 0.1 to 5 moles of the alkali phenolic material per equivalent of sulfiding agent.

When using elemental sulfur as the sulfiding agent, it may be preferable to use a basic catalyst such as sodium hydroxide, or an organic amine, preferably a heterocyclic amine (eg morpholine).

Details of the sulfidation process are known to those skilled in the art.

Sulfurized alkyl phenols useful for preparing overbased detergents generally include diluents and unreacted alkyl phenols, regardless of the manner in which they are prepared, and generally from 2 to 20 mass%, preferably based on the mass of the alkyl sulfide phenols. Contains 4 to 14 mass%, most preferably 6 to 12 mass% sulfur.

As mentioned above, the term “phenol” as used herein includes, for example, phenols modified by chemical reactions with aldehydes and Mannich base-condensed phenols.

Aldehydes whereby the phenol can be modified include, for example, formaldehyde, propionaldehyde and butyraldehyde. Preferred aldehydes are formaldehydes. Aldehyde-modified phenols suitable for use are described, for example, in US-A-5 259 967.

Mannich base-condensed phenols are prepared by the reaction of phenols, aldehydes and amines. Examples of suitable Mannich base-condensed phenols are described in GB-A-2 121 432.

In general, phenols may include substituents other than those mentioned above, provided that such substituents do not significantly impair the surfactant properties of the phenol. Examples of the substituents are methoxy group and halogen atom.

Salicylic acid used according to the invention may be non-sulfurized or sulfided, and may be chemically modified and / or contain further substituents, for example as discussed above for phenols. Processes similar to those described above can also be used to sulfide hydrocarbyl-substituted salicylic acid and are known to those skilled in the art. Salicylic acid is typically prepared by carboxylation of the phenoxide by the Kolbe-Schmitt process, in which case it is usually obtained in a mixture with the non-carboxylated phenol (usually in diluent).

Preferred substituents in oil-soluble salicylic acid from which overbased detergents can be derived therefrom according to the invention are those represented by R in the discussion of phenols above. In alkyl-substituted salicylic acids, the alkyl group advantageously contains 5 to 100, preferably 9 to 30, in particular 14 to 20 carbon atoms.

The sulfonic acids used according to the invention are typically by the sulfonation of hydrocarbyl-substituted, especially alkyl-substituted aromatic hydrocarbons, for example aromatic hydrocarbons obtained from fractional distillation of petroleum by distillation and / or extraction. Or by alkylation of aromatic hydrocarbons. Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, biphenyl or halogen derivatives thereof such as chlorobenzene, chlorotoluene or chloronaphthalene. Alkylation of aromatic hydrocarbons is carried out by alkylating agents having from 3 to 100 carbon atoms, for example haloparaffins, olefins obtainable by dehydrogenation of paraffins, and polymers of polyolefins such as ethylene, propylene and / or butenes. It can be carried out in the presence of a catalyst using an alkylating agent such as. Alkylaryl sulfonic acids typically contain 7 to 100 or more carbon atoms. They contain preferably 16 to 80, or 12 to 40 carbon atoms per alkyl-substituted aromatic moiety, depending on the source from which they are obtained.

When neutralizing these alkylaryl sulfonic acids to produce sulfonates, not only hydrocarbon solvents and / or diluent oils, but also accelerators and viscosity modifiers may also be included in the reaction mixture.

Another type of sulfonic acid that may be used in accordance with the present invention includes alkyl phenol sulfonic acids. The sulfonic acid may be sulfided. Sulfuric acid, whether sulfided or non-sulfurized, is believed to have surfactant properties comparable to sulfonic acid, rather than surfactant properties comparable to phenols.

Sulphonic acids suitable for use according to the invention also include alkyl sulfonic acids, for example alkenyl sulfonic acids. In the compounds, the alkyl groups suitably contain 9 to 100, advantageously 12 to 80, in particular 16 to 60 carbon atoms.

Carboxylic acids that can be used according to the invention include mono- and dicarboxylic acids. Preferred monocarboxylic acids are those containing 1 to 30, in particular 8 to 24, carbon atoms. (When this specification specifies the number of carbon atoms of the carboxylic acid, the carbon atom (s) of the carboxylic acid group (s) are included in that number). Examples of monocarboxylic acids are iso-octanoic acid, stearic acid, oleic acid, palmitic acid and behenic acid. Iso-octanoic acid can optionally be used in the form of a mixture of C ₈ acid isomers sold under the trade name “Cekanoic” from Exxon Chemical. Other suitable acids are those having tertiary substitutions on the α-carbon atoms and dicarboxylic acids having two or more carbon atoms separating the carboxyl groups. Also suitable are dicarboxylic acids having 35 or more, for example 36 to 100, carbon atoms. Unsaturated carboxylic acids can be sulfided. Although salicylic acid contains carboxyl groups, in the present invention they are considered to be separate soldiers of the surfactant and are not considered to be carboxylic acid surfactants. (They also contain hydroxyl groups, but they are not considered to be phenolic surfactants).

Examples of other surfactants that can be used according to the invention include the following compounds and derivatives thereof: naphthenic acid, in particular naphthenic acid, dialkylphosphonic acid, dialkylthiophosphonic acid and dialkyldi, containing one or more alkyl groups Thiophosphoric acid, high molecular weight (preferably ethoxylated) alcohols, dithiocarbamic acid, thiophosphine and dispersants. Surfactants of this type are known to those skilled in the art. Hydrocarbyl-substituted carboxyalkylalkyl-linked phenol type, or dihydrocarbyl esters of alkylene dicarboxylic acids in which alkylene groups are substituted with hydroxy groups and additional carboxylic acid groups, or phenols substituted with one or more hydrocarbyl-substituted aromatic moieties. And surfactants of alkylene-linked polyaromatic molecules comprising one or more carboxyl phenols may also be suitable for use in the present invention; Such surfactants are described in EP-A-708 171.

Another example of a detergent useful in the present invention is optionally sulfided with a carboxylic acid, such as stearic acid, as described, for example, in EP-A-271 262 (LZ-Adibis). Alkaline earth metal hydrocarbyl phenates; And phenolates as described in EP-A-750 659 (Chevron).

Overbased metal compounds, preferably at least two surfactant groups such as phenol, sulfonic acid, carboxylic acid, in which at least two different surfactant groups can be obtained by the preparation of a hybrid material incorporated during the overbased process Overbased calcium detergents containing salicylic acid and naphthenic acid are also suitable for use in the present invention.

Examples of hybrid materials include overbased calcium salts of surfactant phenols and sulfonic acids; Overbased calcium salts of surfactant phenols and carboxylic acids; Overbased calcium salts of surfactant phenol, sulfonic acid and salicylic acid; And overbased calcium salts of surfactant phenols and salicylic acid.

If two or more overbased metal compounds are present, any suitable mass ratio may be used, preferably the mass to mass ratio of any one overbased metal compound to any other metal overbased compound is from 5:95 to In the range 95: 5, for example 90:10 to 10:90, more preferably 20:80 to 80:20, in particular 70:30 to 30:70, advantageously 60:40 to 40:60 Range.

The hybrid detergent preferably comprises at least 5 mass% salicylate, more preferably at least 10 mass% salicylate. The hybrid detergent preferably comprises at least 5 mass% phenate. The amount of salicylate and phenate in the hybrid detergent can be determined using techniques such as chromatography, spectroscopy and / or titration known to those skilled in the art. Hybrid detergents may also include other surfactants such as sulfonates, sulfide phenates, thiophosphates, naphthenates or oil-soluble carboxylates. Hybrid detergents may comprise at least 5% by weight of sulfonate. Surfactant groups are incorporated during the overbased process.

Specific examples of hybrid materials include, for example, WO-A-97 / 46643; WO-A-97 / 46644; WO-A-97 / 46645; WO-A-97 / 46646; And those described in WO-A-97 / 46647.

"Overbased calcium salt of surfactant" means an overbased detergent wherein the metal cation of the oil-insoluble metal salt is essentially a calcium cation. Small amounts of other cations may be present in the oil-insoluble metal salt, but among the oil-insoluble metal salts, typically at least 80 mol%, more typically at least 90 mol%, for example at least 95 mol%, are calcium ions. Other cations other than calcium can be derived from the use in the preparation of overbased detergents, for example, of surfactant salts in which the cation is a metal other than calcium. Preferably, the metal salt of the surfactant is also calcium.

Preferably, the TBN of the hybrid detergent is, as measured by ASTM D2896, at least 300 mg KOH / g, for example at least 330 mg KOH / g, more preferably at least 350 mg KOH / g, even more preferably Is in the range of 400 mg KOH / g or more, most preferably 400 to 600 mg KOH / g, for example 500 mg KOH / g or less.

Preferably, the amount of overbased metal detergent in the lubricant is at least 0.5 mass%, preferably in the range of 5 to 50 mass%, more preferably 10 to 50 mass%, based on the total amount of the lubricant composition.

Overbased metal detergents may or may not be borated, and boron-providing compounds, such as metal borate salts, are typically considered to form part of overbased. Detergents can include both non-borated detergents and borated detergents.

The overbased metal detergent preferably has a sulfated ash content of at least 0.85% (as measured by ASTM D874), more preferably at least 1.0%, even more preferably at least 1.2%.

Detergents or detergents may include phenol as the unreacted component, where the amount of phenol contributes to the total phenolic content present in the trunk piston diesel engine lubricant composition. The phenols present in the trunk piston diesel engine lubricant composition can all originate from detergents or detergents.

Trunk piston engine oils preferably also comprise one or more dispersants, antiwear additives or antioxidants.

Dispersant

The trunk piston diesel engine lubricant composition may comprise one or more dispersants. Dispersants are additives for lubricant compositions whose primary function is to improve engine cleanliness.

A notable class of dispersants is "ashless" which refers to non-metallic organic materials which, in contrast to metal-containing, thus ash-producing materials, do not substantially produce ash upon combustion. Ashless dispersants include long chain hydrocarbons with polar heads whose polarity is derived, for example, from O, P or N atoms. The hydrocarbon is a lipophilic group that provides utility, having from 40 to 500 carbon atoms. Thus, ashless dispersants may include oil soluble polymer hydrocarbon backbones having functional groups capable of binding to the particles to be dispersed.

Examples of ashless dispersants include succinimides such as polyisobutene succinic anhydride; And polyamine condensation products which may or may not be borated.

When present, the dispersant is preferably present in an amount of 0.5 to 5 mass% based on the total amount of the lubricant composition.

Abrasion Resistance Additive

The trunk piston diesel engine lubricant composition may comprise one or more antiwear additives. The wear resistant additive may be metallic or non-metallic and is preferably metallic.

Dihydrocarbyl dithiophosphate metal salts are examples of wear resistant additives. The metal in the dihydrocarbyl dithiophosphate may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or copper. Preferably, zinc salts in the range of 0.1 to 1.5 mass%, preferably 0.5 to 1.3 mass%, based on the total mass of the lubricating oil composition, are preferred. They can be prepared by first producing dihydrocarbyl dithiophosphoric acid (DDPA), usually by reaction of one or more alcohols or phenols with P ₂ S ₅ according to known techniques, and then neutralizing the resulting DDPA with a zinc compound. . For example, dithiophosphoric acid can be prepared by reacting a mixture of primary and secondary alcohols. Alternatively, multiple dithiophosphoric acid containing both the all secondary hydrocarbyl groups and the all primary hydrocarbyl groups can be prepared. To prepare zinc salts, any basic or neutral zinc compound can be used, but oxides, hydroxides and carbonates are most commonly used. Commercial additives often contain excess zinc due to the use of excess basic zinc compounds in the neutralization reaction.

Preferred zinc dihydrocarbyl dithiophosphate is an oil soluble salt of dihydrocarbyl dithiophosphoric acid and can be represented by the formula:

[(RO) (R ¹ O) P (S) S] ₂ Zn

In the above, R and R ¹ contain 1 to 18, preferably 2 to 12, carbon atoms and include radicals such as alkyl, alkenyl, aryl, arylalkyl, alkaryl and alicyclic radicals. Or other hydrocarbyl radicals. Alkyl groups having from 2 to 8 carbon atoms are particularly preferred as R and R ¹ groups. Thus, the radicals are for example ethyl, n-propyl, I-propyl, n-butyl, I-butyl, secondary-butyl, amyl, n-hexyl, I-hexyl, n-octyl, decyl, dodec Silyl, octadecyl, 2-ethylhexyl, phenyl, butylphenyl, cyclohexyl, methylcyclopentyl, propenyl, butenyl. To achieve utility, the total number of carbon atoms in dithiophosphoric acid (ie, in R and R ¹ ) will generally be at least five. Therefore, zinc dihydrocarbyl dithiophosphate may comprise zinc dialkyl dithiophosphate.

If present, the wear resistant additive is preferably present in an amount of 0.10 to 3.0 mass% based on the total amount of lubricant composition.

Antioxidant

The trunk piston diesel engine lubricant composition may include one or more antioxidants. The antioxidant may be amine-based or phenol-based. Examples of the amines include secondary aromatic amines such as diarylamines, for example, diphenylamines in which each phenyl group is alkyl-substituted with an alkyl group having from 4 to 9 carbon atoms. Examples of antioxidants include sterically hindered phenols including mono-phenol and bis-phenol.

Preferably, the antioxidant, if present, is provided in the composition in an amount of up to 3 mass%, based on the total amount of the lubricant composition.

Other additives such as pour point depressants, antifoaming agents, metal antirust agents, and / or demulsifiers may also be provided as the case may be.

The term 'soluble' or 'dispersible', as used herein, does not necessarily indicate that the compound or additive may be soluble, soluble, miscible, or suspended in the oil in full proportion. However, these mean, for example, that the oil is dissolved or reliably dispersed in the oil to an extent sufficient to exert its intended effect in the environment in which it is used. In addition, further incorporation of other additives may also permit incorporation of higher levels of certain additives, if desired.

The lubricant composition of the present invention comprises defined individual (ie distinct) components, which may or may not remain chemically identical before and after mixing.

Although not required, it may be desirable to prepare one or more additive packages or concentrates comprising such additives, wherein the additives may be simultaneously added to an oil having a lubricating viscosity to produce a lubricating oil composition. Dissolution of the additive package (s) in the lubricating oil may be facilitated by the solvent and by mixing with mild heating, but this is not essential. The additive package (s) typically contain the additive (s) in an amount suitable to provide the desired concentration and / or the intended function in the final blend when the additive package (s) are mixed with a predetermined amount of base lubricant. Formulated to carry out.

Thus, on the basis of the additive package, for example, it contains the active ingredient in an amount of from 5 to 90 mass%, preferably from 5 to 75 mass%, most preferably from 8 to 60 mass%, of the appropriate proportions of the additives. The additives may be mixed with small amounts of base oils or other compatible solvents with other preferred additives to produce an additive package that is a base oil.

The final blend may typically contain about 5-40 mass% of the additive package (s), with the remainder being base oils.

Example

The invention is illustrated by the following examples, but by no means limiting it.

Example

The following examples used a centrifuge water screening test that assessed the oil's ability to shut off water from the prepared test mixture of oil and water. The test used an Alfa Laval MAB103B 2.0 centrifuge coupled to a Watson Larlow peristaltic pump. 2 liters of water was charged in the centrifuge. The amount of deposits formed in the centrifuge during the test was measured. The test was performed at 87 ° C. Pre-measured amounts of water and test oil were mixed and then passed through a centrifuge at a rate of 2 L / min. The test was run for 1 hour 30 minutes to allow the mixture to pass about 10 times through the centrifuge. Centrifuge was metered before and after the test. Poor trunk piston diesel engine lubricant compositions produce higher amounts of deposits in centrifuge systems.

Trunk piston engine oil ('TPEO') having a TBN of about 40 was prepared. TPEO was subjected to centrifuge water blocking test. Details of TPEO and test results are shown in Table 1 below.

Example Reference Example One 2 Co-additive (mass%) 16 16 16 Lubricant (mass%) 75.5 82.3 80.94 Brightstock (mass%) 8.5 - - PIB 2225 (mass%) - 1.7 - PIB 450 (mass%) - - 3.06 TBN 41.17 40.46 40.63 VI 104 105 104 Deposit (g) ball 4 8 5 Hood 3 0 0 Upper disc One 0 0 Distributor & Disc 37 4 28 Total deposit (g) 45 12 33

PIB = polyisobutylene (corresponding number average molecular weight).

The results show that Examples 1 and 2, which contain PIB and do not contain Brightstock, perform better in the water-blocking test than reference examples which contain Brightstock and do not contain PIB.

Claims (7)

As an additive constituting 1-25% by mass of the trunk piston diesel engine lubricant composition, it has a number average molecular weight in the range from 400 to 8000, for example in the range 1,300 to 2,225, and 50 to 50,000 mm ² / sec, for example 630. Polyisobutylene having a kinematic viscosity at 100 ° C. in the range of from 2,500 mm ² / sec to produce deposits in the centrifuge of the engine when the lubricant composition lubricates the engine in operation of a trunk piston diesel engine For reducing the The method of claim 1,
The composition comprises less than 0.5 mass% brightstock, preferably less than 0.1 mass% brightstock. The method of claim 1,
The composition is substantially free of brightstock. The method of claim 1,
Use wherein the composition does not contain brightstock. The method according to any one of claims 1 to 4,
The number average molecular weight of the polyisobutylene ranges from 900 to 8,000; Or in the range from 1,000 to 6,000, for example in the range from 1,500 to 5,000, for example in the range from 2,000 to 5,000. 6. The method according to any one of claims 1 to 5,
Kinematic viscosity at 100 ° C. of polyisobutylene ranges from 200 to 6,000 mm ² / sec; For example in the range from 2,000 to 6,000 mm ² / second, for example in the range from 2,000 to 5,000 mm ² / second, for example in the range from 3,000 to 4,500 mm ² / second. 6. The method according to any one of claims 1 to 5,
The TBN of the composition is at least 30, for example at least 35, for example at least 45, for example at least 50, for example at most 60 or at most 70, for example for 50 to 60.