KR102154097B1 - Lubricant composition based on metal nanoparticles - Google Patents

Abstract

The present invention relates to a lubricating oil composition comprising a high molecular weight dispersant and metal nanoparticles. The lubricating oil composition according to the present invention has excellent stability and excellent peel resistance at the same time.

Description

Lubricant composition based on metal nanoparticles {LUBRICANT COMPOSITION BASED ON METAL NANOPARTICLES}

The invention can be applied in the field of lubricating oil and in particular in the field of lubricating oil for vehicles, in particular in the field of lubricating oil for motor vehicle transmission components. The present invention relates to a lubricating oil composition comprising metal nanoparticles. More particularly, the present invention relates to a lubricating oil composition comprising metal nanoparticles and a dispersant having a high weight-average molecular weight. The lubricating oil composition according to the present invention has excellent stability and excellent anti-flaking at the same time.

In addition, the present invention relates to a method for reducing delamination of mechanical parts using such lubricating oil compositions.

In addition, the present invention relates to an addition concentration type composition comprising a dispersant having a high weight average molecular weight and metal nanoparticles.

Automotive transmission components operate under high loads and high speeds. Therefore, the oil for such transmission parts must be effective in protecting the parts from wear and fatigue, and in particular to protect gear teeth from delamination.

Wear phenomena correspond to the erosion and wear of metal on a surface while friction occurs between moving parts.

Peeling phenomenon is different from wear phenomenon. Peeling is the deterioration of the part due to fatigue and occurs after a long aging time, previously visible deterioration. It is known that this phenomenon occurs as cracks begin at a certain depth below the surface, and when these cracks spread and vertical cracks occur on the surface, the fragments suddenly peel off.

This phenomenon can be prevented by reducing the contact stress and reducing friction while avoiding sticking by means of a suitable shaped part. Lubricating oils are included in this prevention method because of the physicochemical reactivity of the lubricant additives.

Antiwear additives and extreme pressure additives containing sulfur-, phosphorus-, phosphorus/sulfur- or boric acid are known to protect transmission oils from exfoliation. In addition, other additives can have a positive or negative effect on the propagation of cracks inside the part, and thus delamination.

In manual gearboxes, the presence of synchronizers induces additional stress. In fact, these components include cone and ring arrangements, the friction between them must be controlled in advance. Thus, the friction should be sufficient to synchronize the gears, but there is a risk that the cones and rings can loosen, blocking the synchronizer.

In addition, if the friction level is not suitable for the part shape, wear occurs in the cone-ring assembly.

The friction level can be adjusted by adding a friction modifier with oil for the gearbox.

Thus, in oils for manual gearboxes, anti-wear additives, extreme pressure additives and friction modifiers coexist, all of which have an effect on the activity at the surface of the part and potentially on the friction level and delamination phenomena.

In particular, in order to improve the abrasion resistance of these oils, a lubricating oil composition comprising an organophosphorus- and/or organosulfur- and/or organophosphorus/sulfur-containing wear-resistant and extreme pressure compound and an organomolybdenum-type friction modifier compound How to make is known.

Other compounds useful for lubricating mechanical parts, especially engine parts, have been described.

The use of nanoparticles, particularly metal nanoparticles, in lubricating oil compositions has been described. Accordingly, WO 2007/035626 is particularly useful for metal nanoparticles based on lithium, potassium, sodium, copper, magnesium, calcium, barium or mixtures thereof. A lubricating oil composition comprising particles has been described.

US2011/0152142 A1 discloses a composition comprising at least one base oil, at least one dispersant and nanoparticles of a metal hydroxide in the form of crystals. The composition is used to lubricate the combustion engine and neutralize the acid formed during combustion.

US2006/0100292 A1 describes a method for preparing a grease in which at least one base oil, at least one dispersant, and nanoparticles of crystalline metal hydroxide are mixed. This method has the advantage of suppressing foam formation, reducing environmental risk and reducing reaction time.

US2009/0203563 describes a method for preparing an overbased or neutral detergent. The method used a surfactant and an organic medium as a composition comprising at least one base oil, at least one dispersant, and nanoparticles of crystalline metal hydroxide.

WO2011/081538 A1 describes a method for producing particles of molybdenum disulphide and tungsten disulphide, the method comprising passing and compressing a mixture of molybdenum disulphide and tungsten disulphide between plates covered with glue. It consists of steps. WO2011/081538 A1 does not describe a lubricating oil composition.

CN 101691517 describes engine oils that contain dispersants and tungsten disulfide nanoparticles, which can improve engine service life and reduce fuel consumption. However, the total amount of tungsten disulfide nanoparticles is 15-34%. Such content is incompatible with lubricating oil compositions, especially lubricating oil compositions for transmissions, as they may destabilize the composition. Therefore, no indication is given in CN 101691517 above regarding the peeling resistance properties of oil, especially for transmission parts of automobiles.

EP 1 　 953 　 196 is applied to metal nanoparticles, in particular zinc, zirconium, cerium, titanium, aluminum, indium or tin in organic solvents and in the presence of a polymeric dispersant of type PIBSA (polyisobutenyl succinic anhydride). The dispersion of the based metal oxide was described. However, EP 1 　 953 　 196 does not relate to the field of lubricating oil compositions, and in particular does not disclose a lubricating oil composition comprising at least one base oil and metal nanoparticles. The organic solvent mentioned in EP 1°953°196 above does not have lubricating properties. In addition, the organic solvent has a flash point of less than 100° C., which is incompatible in lubricating oil applications where the implementation temperature is 100° C. or higher. In addition, no indication is given in EP 1?953?196, in particular, regarding the peeling resistance properties of mechanical parts for transmission parts of automobiles.

Therefore, it is preferable to use a lubricating oil composition, in particular a lubricating oil composition for automobiles, which is stable and can be reduced, or in particular can eliminate delamination in transmission parts, more particularly gearboxes.

In addition, it is preferable to use a lubricating oil composition, particularly a lubricating oil composition for automobiles, which has excellent peel resistance while maintaining sufficient frictional properties.

It is an object of the present invention to provide a lubricating oil composition that overcomes some or all of the above-mentioned disadvantages.

Another object of the present invention is to provide and easily use a stable lubricant composition.

Another object of the present invention is to provide a lubrication method capable of reducing the delamination of mechanical parts, more particularly transmission parts of automobiles.

Accordingly, the subject matter of the present invention comprises at least one base oil, at least one dispersant having a weight average molecular weight of 2000 Daltons or more, and metal nanoparticles having a content of 0.01 to 2% by weight based on the total weight of the lubricating oil composition. In the lubricating oil composition, the metal nanoparticles are concentric polyhedrons in sheets or with a multilayer structure.

According to the invention, the weight average molecular weight of the dispersant is determined according to standard ASTM D5296.

Surprisingly, Applicants claim that the presence of a dispersant having a weight average molecular weight of 2000 Daltons or more in a lubricating oil composition comprising at least one base oil and metal nanoparticles not only improves the stability of the lubricating oil composition, but also gives the composition very excellent peel resistance. Found it.

Accordingly, the present invention can prepare a lubricating oil composition comprising a reduced content of metal nanoparticles and having excellent peel resistance.

Advantageously, with the lubricating oil composition according to the invention, the risk of residual deposition of metal nanoparticles to mechanical parts and more particularly to transmission parts of automobiles may be significantly reduced or eliminated.

Preferably, the lubricating oil composition according to the invention has an improved storage stability as well as a viscosity that does not change or changes only very slightly.

In an embodiment, the lubricating oil composition consists essentially of at least one base oil, at least one dispersant having a weight average molecular weight of 2000 Daltons or more, and metal nanoparticles at least 0.01 to 2% by weight based on the total weight of the lubricating oil composition.

Further, the present invention relates to a transmission oil comprising the lubricating oil composition described above.

The invention also relates to the use of the aforementioned lubricating oil composition for lubricating gearboxes or axles, preferably gearboxes of motor vehicles, preferably manual gearboxes.

The invention also relates to a process for reducing delamination of a machine part, preferably of a transmission part, preferably of a gear box or axle, comprising the step of contacting the machine part with at least the aforementioned lubricating oil composition.

In addition, the present invention relates to an additive-rich type composition comprising at least one dispersant having a weight average molecular weight of 2000 Daltons or more and tungsten disulfide nanoparticles.

1 shows a simulated gearbox 111, an electric motor 112, a torque meter 113, a torque generating device 114, a gearbox 115 containing the torque to be tested, and a differential 116. ), output shaft (116), input shaft (118), flaking detection system (119), fifth gear (120), reverse gear (121), fourth gear (122), a closed-loop power circulation bench comprising a third gear 123, a second gear 124, a first gear 125 and a drive belt 126.
Figure 2 is a photograph of a gearbox housing after 600 hours of testing a closed loop power circulation bench with the composition according to the present invention.
3 is a photograph of a gearbox housing after 400 hours testing of a closed loop circulation bench with a composition not in accordance with the present invention.

The percentages given below correspond to the mass percent (%) of the active ingredient.

Metal nanoparticles

The lubricating oil composition according to the present invention includes metal nanoparticles in an amount of 0.01 to 2% by weight based on the total weight of the lubricating oil composition.

Metal nanoparticles in particular mean metal particles, generally solid, and the average size of the metal nanoparticles is 600 nm or less.

Preferably, the metal nanoparticles are at least 80% by mass of at least one metal or at least 80% by mass of at least one metal alloy or at least 80% by mass of at least one metal, in particular a transition metal, based on the total mass of the nanoparticles, It consists of chalcogenides.

Preferably, the metal nanoparticles are at least 90% by mass of at least one metal or at least 90% by mass of at least one metal alloy or at least 90% by mass of at least one metal, especially a transition metal knife, based on the total mass of the nanoparticles. It is made of kogenide.

Preferably, the metal nanoparticles are at least 99% by mass of at least one metal or at least 99% by mass of at least one metal alloy or at least 99% by mass of at least one metal, in particular a transition metal, based on the total mass of the nanoparticles, It consists of chalcogenides, and the remaining 1% consists of impurities.

Preferably, the metal of the formed metal nanoparticles is tungsten, molybdenum, zirconium, hafnium, platinum, rhenium, titanium, tantalum, It may be selected from the group formed of niobium, zinc, cerium, aluminum, indium, and tin.

The metal nanoparticles may have a spherical shape, a thin film shape, a fiber shape, a tube shape, and a fullerene-type structure shape.

Preferably, the metal nanoparticles used in the composition according to the present invention are solid metal nanoparticles having a fullerene-type (or fullerene type) structure, represented by the formula MX _n , wherein M is a transition metal, and X is a caltogen Represents a cargo and is n=2 or n=3 depending on the oxidation state of the transition metal M.

Preferably, M is selected from the group formed by tungsten, molybdenum, zirconium, hafnium, platinum, rhenium, titanium, tantalum and niobium.

More preferably, M is selected from the group formed by molybdenum and tungsten.

More preferably, M is tungsten.

Preferably, X is selected from the group formed by oxygen, sulfur, selenium and tellurium.

Preferably, X is selected from sulfur or tellurium.

More preferably, X is sulfur.

Preferably, the metal nanoparticles according to the present invention are MoS ₂ , MoSe ₂ , MoTe ₂ , WS ₂ , WSe ₂ , ZrS ₂ , ZrSe ₂ , HfS ₂ , HfSe ₂ , PtS ₂ , ReS ₂ , ReSe ₂ , TiS ₃ , It is selected from the group formed by ZrS ₃ , ZrSe ₃ , HfS ₃ , HfSe ₃ , TiS ₂ , TaS ₂ , TaSe ₂ , NbS ₂ , NbSe ₂ and NbTe ₂ .

Preferably, the metal nanoparticles according to the present invention are selected from the group formed by WS ₂ , WSe ₂ , MoS ₂ and MoSe ₂ , preferably WS ₂ and MoS ₂ , preferably WS ₂ .

Preferably, the nanoparticles according to the present invention have a fullerene-type structure.

The term fullerene refers to a closed convex polyhedron nanostructure made of carbon atoms. Fullerene is similar to graphite, which is made up of sheets of cross-linked hexagonal rings, and includes pentagonal and sometimes heptagonal rings that prevent the structure from flattening.

Studies of the fullerene type structure have shown that this structure is not limited to a carbon-containing material, but in particular, in the case of nanoparticles including chalcogenide and transition metal, it can be produced in the nanoparticles of any material in the shape of a sheet. Such structures are similar to carbon fullerenes and are referred to as inorganic fullerene or fullerene type structures (or "Inorganic Fullerene-like materials", or "IF"). Fullerene type structures have been described in particular by Tenne, R., Margulis, L., Genut M. Hodes, G. Nature 1992, 360, 444. EP 0580 019 in particular describes fullerene type structures and methods for their synthesis.

Metal nanoparticles are spherical, closed structures, and almost completely rely on the synthetic process used. Nanoparticles according to the present invention are concentric polyhedrons having a multilayer structure or a sheet structure. That is, it is regarded as an "onion" or "if nested" structure.

The concentric polyhedron having a multilayer structure or a sheet structure more particularly means a substantially spherical polyhedron, and the different layers of the concentric polyhedron form a plurality of spherical shapes having the same center.

The multilayer structure or sheet structure of the nanoparticles according to the present invention can in particular be measured by transmission electron microscopy (TEM).

In an embodiment of the present invention, the metal nanoparticles are multi-layered metal nanoparticles including 2 to 500 layers, preferably 20 to 200 layers, and preferably 20 to 100 layers.

The number of layers of nanoparticles according to the invention can in particular be determined by transmission electron microscopy.

The average size of the metal nanoparticles according to the present invention is 5 to 600 nm, preferably 20 to 400 nm, preferably 50 to 200 nm. The size of the metal nanoparticles according to the present invention can be measured using an image obtained by a transmission electron microscope or a high resolution transmission electron microscopy. The average size of the particles can be determined by measuring the size of at least 50 solid particles visible on a transmission electron microscopic photograph. The median value of the histogram of the distribution of the measured size of the solid particles is the average size of the solid particles used in the lubricating oil composition according to the present invention.

In an embodiment of the present invention, the average diameter of the primary metal nanoparticles according to the present invention is 10 to 100 nm, preferably 30 to 70 nm.

The average diameter of the nanoparticles according to the present invention can in particular be measured by a transmission electron microscope.

Preferably, the weight of the metal nanoparticles is 0.05 to 2% by weight, preferably 0.1 to 1% by weight, preferably 0.1 to 0.5% by weight based on the total weight of the lubricating oil composition.

As an example of the metal nanoparticles according to the present invention, the product NanoLub Gear Oil Concentrate sold by Nanomaterials is a natural oil or PAO (Poly Alfa Olefin) type oil. In the form of a dispersant of multi-layered nanoparticles of tungsten disulfide.

Dispersant

The lubricating oil composition according to the present invention comprises at least one dispersant having a weight average molecular weight of 2000 Daltons or more.

According to the invention, the weight average molecular weight of the dispersant is determined according to standard ASTM D5296.

A dispersant within the meaning of the present invention is more particularly any compound that keeps the metal nanoparticles suspended.

In an embodiment of the present invention, the dispersant is selected from a compound comprising at least one succinimide group, a polyolefin, an olefin copolymer (OCP), a copolymer comprising at least one styrene unit, a polyacrylate or a derivative thereof. Can be.

Derivative means any compound containing at least one group or polymer chain as described above.

Preferably, the dispersant according to the invention is selected from compounds comprising at least one succinimide group.

In a preferred embodiment of the present invention, the dispersant may be selected from a compound containing at least one substituted succinimide group, a compound containing at least two substituted succinimide groups, and the succinimide group has a nitrogen atom. It is connected to a polyamine group at the peak of the succinimide group.

A substituted succinimide group within the meaning of the present invention means a succinimide group substituted with a hydrocarbon-containing group containing at least one carbon-containing vertex of 8 to 400 carbon atoms.

In a preferred embodiment of the present invention, the dispersant is selected from polyisobutylene succinimide-polyamines.

Preferably, the dispersant is a substituted succinimide of formula (I) or a substituted succinimide of formula (II):

X is an integer from 1 to 10, preferably 2, 3, 4, 5 or 6;

Y is an integer from 2 to 10;

R ₁ is a hydrogen atom, a linear or branched alkyl group containing 2 to 20 carbon atoms, a heteroalkyl group containing 2 to 20 carbon atoms, and a hide containing O, N and S, 2 to 20 carbon atoms At least one heteroatom selected from a oxyalkyl group or -(CH2) _x -O-(CH2) _x -OH group;

R ₂ is a linear or branched alkyl group containing 8 to 400 carbon atoms, preferably 50 to 200 carbon atoms, an aryl group containing 8 to 400 carbon atoms, preferably 50 to 200 carbon atoms, 8 It is a linear or branched arylalkyl group containing ~400 carbon atoms, preferably 50 ~ 200 carbon atoms, or a linear or branched alkylaryl group containing 8 ~ 400 carbon atoms, preferably 50 ~ 200 carbon atoms, ;

R ₃ and R ₄ are the same or different, and each is a linear or branched alkyl group containing 1 to 25 carbon atoms, an alkoxy group containing 1 to 12 carbon atoms, an alkylene group containing 2 to 6 carbon atoms , A hydroxylated alkylene group containing 2 to 12 carbon atoms or an aminated alkylene group containing 2 to 12 carbon atoms.

Preferably, the dispersant is a substituted succinimide of formula (I) or a substituted succinimide of formula (II), wherein R ₂ is a polyisobutylene group.

More preferably, the dispersant is a substituted succinimide of formula (II), and R ₂ is a polyisobutylene group in the formula (II).

More preferably, the dispersant is a substituted succinimide of formula (II):

R ₁ is a -(CH2) _x -O-(CH2) _x -OH group,

R ₂ is a polyisobutylene group,

X is 2,

Y is 5.

Preferably, the dispersant according to the present invention has a weight average molecular weight of 2000 to 15000 Daltons, preferably 2500 to 10000 Daltons, preferably 3000 to 7000 Daltons.

Preferably, the dispersant is also a number-average molecular weight of 1000 Daltons, preferably 1000 to 5000 Daltons or more, more preferably 1000 to 5000 Daltons, more preferably 1800 to 3500 Daltons, preferably 1800 to 3000 Daltons. Have.

According to the present invention, the number average molecular weight of the dispersant is determined according to standard ASTM D5296.

In a preferred embodiment of the present invention, the content of the dispersant having a weight average molecular weight of 2000 Daltons or more is 0.1 to 10% by weight, preferably 0.1 to 5% by weight, preferably 0.1 to 3% by weight, based on the total weight of the lubricating oil composition.

As an example of the dispersant according to the invention, OLOA 13000 from Oronite may be mentioned.

Other compounds

Base oil (Base oils)

The lubricating oil composition according to the invention may comprise a lubricating oil base, mineral, synthetic or natural, animal or vegetable type suitable for using them.

The base oil or oil used in the lubricating oil composition according to the present invention is either single or mixed, and synthetic minerals or synthetic origins of groups I to V according to the grades defined in the API classification method (or their equivalents according to the ATIEL classification method) as summarized below. It can be oil. In addition, the base oil or oil used in the lubricating oil composition used according to the invention may be selected from oils of synthetic origin of group VI according to the ATIEL classification method. The API taxonomy was defined in the September 2012 American Petroleum Institute 1509 "Engine oil Licensing and Certification System" 17th edition.

Saturation content Sulfur content Viscosity index (VI) Group I mineral oil <90% > 0.03% 80 ≤ VI <120 Group II Hydrocracked Oils ≥ 90% 2 0.03% 80 ≤ VI <120 Group III
Hydrolyzed or hydro-isomerized oils ≥ 90% 2 0.03% ≥ 120 Group IV Poly Alpha Olefins (PAO) Group V Esters and other bases not included in the bases of groups I to V Group VI* Poly Internal (PIO)

* Limited to ATIEL classification method

The mineral base oil according to the present invention is subjected to atmospheric distillation and vacuum of crude oil by purification actions such as solvent extraction, deasphalation, solvent dewaxing, hydrogenation treatment, hydrolysis and hydrogen isomerization, and hydrofinishing. And any type of base obtained by distillation.

In addition, the base oil of the lubricating oil composition according to the present invention may be a synthetic oil such as poly alpha olefin (PAO) or certain esters of carboxylic acids and alcohols, in particular polyol esters.

Poly alpha olefins used as base oils are obtained from monomers having, for example, 4 to 32 carbon atoms (e.g., octene, decene), and have a viscosity of 1.5 to 15 cSt at 100°C as measured according to standard ASTM D445. Have. Mixtures of synthetic or mineral oils can be used.

Limited to the use of certain lubricating oil bases for producing lubricating oil compositions according to the invention, except that they must have properties suitable for use in gearboxes, in particular automotive gearboxes, in particular manual gearboxes, in particular viscosity, viscosity index, sulfur content, oxidation resistance There is this.

Preferably, the base oil has a flash point of 150°C or higher, preferably 170°C or higher, more preferably 190°C or higher.

Preferably, selected from the group formed by the base of group I, the base of group II, the base of group III, the base of group IV, the base of group V, and mixtures thereof of the API classification method (or their equivalents according to the ATIEL classification method). do. Also, the base oil may be selected from the base of Group VI of the ATIEL classification method.

In an embodiment of the present invention, the base oil is selected from the group formed by the base of group III, the base of group IV, the base of group V and mixtures thereof of the API classification.

In a preferred embodiment of the invention, the base oil is a mixture of bases of Group IV and Group V of the API classification.

In a preferred embodiment of the invention, the base oil is selected from poly alpha olefins (PAOs) and esters, preferably polyol esters or mixtures thereof.

In a more preferred embodiment of the invention, the base oil is a mixture of at least one poly alpha olefin and at least one ester, preferably a polyol ester.

In an embodiment of the present invention, the base oil or base oils may represent at least 50% by mass, preferably at least 60% by mass or at least 70% by mass relative to the total mass of the lubricating oil composition. In general, the base oil or base oil represents 75 to 99.89% by weight based on the total weight of the lubricating oil composition according to the present invention.

Preferably, the viscosity at 100° C. of the lubricating oil composition according to the present invention measured according to standard ASTM D445 is 4 to 41 cSt, preferably 4.1 to 32.5 cSt according to the classification method SAE J 306.

Preferred grades are for all grades included between grades SAE 75W and SAE 140, especially grades SAE 75W, SAE 75W-80 and SAE 75W-90.

Preferably, the lubricating oil composition according to the present invention has a viscosity index (VI) of 95 or higher (measured according to standard ASTM 2270).

In a preferred embodiment, the subject of the invention lies in a transmission oil comprising a lubricating oil composition according to the invention.

All features and preferences in the lubricating oil composition apply to the trans oil according to the invention.

Additional additives

The lubricating oil composition according to the present invention is an additive of any type suitable for use as a composition of a transmission oil, for example, an additional dispersant, a polymer viscosity index improver, an antioxidant present in the usual content required for application, used alone or in combination. , Corrosion inhibitors, friction modifiers or anti-foaming agents.

The additional dispersant is selected from dispersants other than those having a weight average molecular weight of 2000 Daltons or more.

These additional dispersants are particularly capable of removing insoluble solid contaminants consisting of by-products of oxidation and combustion residues (soots) that are formed when the oil retention and lubricating oil composition of the suspension is used.

In an embodiment of the present invention, the additional dispersant is selected from the group formed by compounds of formula (I) or (II) having a weight average molecular weight of 2000 Daltons or more and other succinimides or Mannich bases. Can be.

In an embodiment, the lubricating oil composition according to the present invention may also contain at least one additional additive selected from polymer viscosity index improvers, antioxidants and mixtures thereof.

The polymer viscosity index improver can be selected from polymers other than the dispersant according to the present invention.

The polymer viscosity index improver consists of a group of shear-stable polymers, preferably ethylene and alpha-olefin copolymers, in particular ethylene/propylene copolymers. Can be selected from a group.

In a preferred embodiment of the present invention, the additional additive is a polymer viscosity index improver selected from ethylene and alpha-olefin copolymers.

Antioxidants are amine containing antioxidants, preferably diphenylamines, in particular dialkylphenylamines such as octadiphenylamines, phenyl-alpha-naphthyl amines. , Phenolic antioxidants (dibutylhydroxytoluene BHT and derivatives) or sulfur containing antioxidants (sulfated phenates).

In a preferred embodiment of the present invention, the additional additive is an antioxidant selected from dialkylphenylamines, phenolic antioxidants and mixtures thereof used alone.

The friction modifier may be an ash-free compound or a compound providing metallic elements separated from the metal nanoparticles according to the present invention. Among the compounds providing the metal element, a complex of transition metals such as Mo, Sb, Sn, Fe, Cu, Zn, for example, molybdenum dithiocarbamate or dithiophosphate may be mentioned, and their ligands May be a hydrocarbon-containing compound containing oxygen, nitrogen, sulfur or phosphorus atoms. Ash-free friction modifiers are of organic origin, monoesters of fatty acids and polyols, alkoxylated amines, alkoxylated fatty amines, amine phosphates, fatty alcohols, and fatty epoxides. Fatty epoxides, borated fatty epoxides, fatty amines or glycerol esters of fatty acids. "Fatty" means a hydrocarbon containing group containing 8 to 24 carbon atoms within the meaning of the present invention.

In a preferred embodiment of the present invention, the additional additive is a friction modifier selected from molybdenum dithiomabamate, amine phosphate and fatty alcohol, used alone or in combination.

Anti-corrosion additives may be selected from phenol derivatives, in particular ethoxylated phenol derivatives, and are substituted with alkyl groups in the ortho position. The corrosion inhibitor may be dimercaptothiadiazole derivatives.

In a more preferred embodiment of the present invention, the additional additive is an antioxidant selected from the group formed by ethylene/alpha-olefin copolymers, in particular ethylene/propylene copolymers, and polymer viscosity. And a mixture of index enhancers.

In a more preferred embodiment of the present invention, the further additive comprises a mixture of amine containing antioxidants, phenolic antioxidants and polymer viscosity index improvers selected from ethylene and alpha-olefin copolymers.

In an embodiment of the present invention, the mass ratio (metal nanoparticles: dispersant) is 1/50 to 10/1, preferably 1/50 to 5/1, more preferably 1/30 to 5/1, more preferably 1/ It is 10-5/1.

The subject of the present invention lies in a lubricating oil composition comprising:

-50-99.89% of at least one base oil;

-0.01-2% of metal nanoparticles; And

-0.1-10% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more.

All the properties and preferences described above for base oils, metal nanoparticles and dispersants apply to the above lubricating oil compositions.

In the examples, the subject of the present invention lies in a lubricating oil composition comprising:

-50-99.79% of at least one base oil;

-0.01-2% of metal nanoparticles;

-0.1-10% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more; And

-0.1-10%, preferably 2-5%, in particular 3.5% of at least one additive.

All the properties and preferences described above for base oils, metal nanoparticles and dispersants apply to the above lubricating oil compositions.

In the examples, the subject of the invention lies in a lubricating oil composition consisting essentially of:

-50-99.9% of at least one base oil;

-0.01-2% of metal nanoparticles; And

-0.1-10% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more.

All the properties and preferences described above for base oils, metal nanoparticles and dispersants apply to the above lubricating oil compositions.

In the examples, the subject of the invention lies in a lubricating oil composition consisting essentially of:

-50-99.79% of at least one base oil;

-0.01-2% of metal nanoparticles;

-0.1-10% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more; And

-0.1-10%, preferably 2-5%, in particular 3.5% of at least one additive.

All the properties and preferences described above for base oils, metal nanoparticles and dispersants apply to the above lubricating oil compositions.

In addition, the subject matter of the present invention lies in the composition of the additive concentrate type comprising:

-1-15% tungsten disulfide nanoparticles; And

-5 to 99% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more.

All of the above-described properties and preferences for tungsten disulfide nanoparticles and dispersants apply to the above lubricant composition. Preferably, the tungsten disulfide nanoparticles have a fullerene type structure.

In addition, the present invention relates to a composition of the additive concentration type comprising:

-1-15% tungsten disulfide nanoparticles; And

-15-89% of at least one dispersant having a weight average molecular weight of 2000 Daltons or more; And

-10 to 59% of at least one additional additive.

All the properties and preferences described above for tungsten disulfide nanoparticles, dispersants and additional additives apply to the above lubricant composition. Preferably, the tungsten disulfide nanoparticles have a fullerene type structure.

In an embodiment of the present invention, at least one base oil may be added to the additive concentrated type composition according to the present invention to obtain the lubricating oil composition according to the present invention. Preferably, the base oil is a base oil selected from the group formed by base oils of group III, base oils of group IV, base oils of group V and mixtures thereof of the API classification.

In a preferred embodiment of the present invention, the base oil is a mixture of base oils of group IV and group V of the API classification method, preferably the base oil is selected from poly alpha olefins (PAOs) and esters and mixtures thereof. In a more preferred embodiment of the invention, the base oil is a mixture of at least one poly alpha olefin and at least one ester, preferably a polyol ester.

part

The lubricating oil composition according to the invention comprises at least one machine or mechanical component, in particular bearings, gears, universal joints, transmissions, pistons/rings/liners. system, camshafts, clutches, manual or automatic gearboxes, axles, rocker arms, housings, etc.

In a preferred embodiment, the lubricating oil composition according to the invention is capable of lubricating transmissions, clutches, manual and automatic gearboxes, preferably mechanical parts or mechanical components of manual gearboxes.

In addition, the subject of the present invention lies in a process for reducing peeling of a mechanical part, preferably a transmission part, preferably a gearbox or axle, the process obtained from the above additive-concentrated type composition or the above-described lubricating oil composition and the machine part. And contacting.

All features and preferences expressed for the lubricating oil composition apply to the process of reducing delamination of mechanical parts according to the invention.

The subject of the invention is also the use of the lubricating oil composition according to the invention for lubrication of a gearbox or axle, preferably a gearbox of a motor vehicle.

In a preferred embodiment, the invention relates to the use of a lubricating oil composition according to the invention for lubrication of a manual gearbox of a motor vehicle.

In addition, all the features and preferences indicated for the lubricating oil composition apply to the use for lubricating the gearbox according to the invention.

The subject of the invention also lies in the use of the lubricating oil composition according to the invention for reducing delamination of mechanical parts, preferably transmission parts, more preferably gearboxes or axles.

In a preferred embodiment, the invention resides in the use of a lubricating oil composition according to the invention for reducing delamination of a manual gearbox.

All the features and preferences indicated for the lubricating oil composition apply to the use of reducing peeling according to the invention.

Other subjects of the invention and their implementation will be understood in more detail with reference to the following examples. These examples are given as indicators without limiting the invention.

excuse:

Example 1: Stability evaluation of the lubricating oil composition according to the present invention

The stability of the lubricating oil composition according to the present invention is measured by monitoring the concentration of tungsten disulfide nanoparticles in the supernatant phase of the composition over time.

Thus, other lubricating oil compositions are prepared from the following compounds:

-Base oils of group III;

-A mixture of 20% tungsten disulfide nanoparticles in the active substance of the oil (NanoLub Gear Oil Concentrate sold by Nanomaterials);

-Dispersant 1: PIB succinimide type dispersant having a weight average molecular weight measured according to the standard ASTM D5296 of 1921 Da and a number average molecular weight measured according to the standard ASTM D5296 of 1755 Da;

Dispersant 2: A dispersant of PIB succinimide having a weight average molecular weight measured according to the standard ASTM D5296 of 1514 Da and a number average molecular weight measured according to the standard ASTM D5296 of 1328 Da;

-Dispersant 3: A dispersant of the succinimide ester type having a weight average molecular weight measured according to the standard ASTM D5296 of 1132 Da and a number average molecular weight measured according to the standard ASTM D5296 of 1046 Da;

-Dispersant 4: PIB succinimide type dispersant according to the present invention having a weight average molecular weight measured according to standard ASTM D5296 of 6370 Da and a number average molecular weight measured according to standard ASTM D5296 of 2850 Da (OLOA 13000 of Oronite) ; And

-Dispersant 5: PIB succinimide type dispersant according to the present invention having a weight average molecular weight measured according to the standard ASTM D5296 of 3085 Da and a number average molecular weight measured according to the standard ASTM D5296 of 1805 Da.

Other compositions L ₁ to L ₅ are described in Table 2: The percentages indicated correspond to the mass percentages (%).

Composition L ₁
(Comparative example) L ₂
(Comparative example) L ₃
(Comparative example) L ₄
(Invention) L ₅
(Invention) Base oil of group III 89 89 89 89 89 Tungsten Disulfide Nanoparticles (NanoLub Gear Oil Concentrate) One One One One One Dispersant 1 10 Dispersant 2 10 Dispersant 3 10 Dispersant 4 10 Dispersant 5 10

Each of the compositions L ₁ to L ₅ is prepared according to the following sequence:

-Adding a dispersant;

-Adding a dispersion of tungsten disulfide nanoparticles;

-Magnetic stirring for 1 hour;

-Adding base oil;

-Heating and stirring at 60 ~ 70 ℃ for 1 hour;

-Stirring overnight without heating (about 16 hours); And

-15 minutes ultrasonic bath (ultrasound bath).

The protocol for monitoring the concentration over time of tungsten disulfide nanoparticles in the supernatant of each of the compositions L ₁ to L ₅ is defined as:

i) calibration curve at t = Oh showing the absorbance as a function of the content of tungsten disulfide nanoparticles;

ii) 3-4 samples of different masses of the composition after stirring in an ultrasonic bath for 15 minutes;

iii) addition of 20 ml of cyclohexane;

iv) measurement of absorbance (wavelength at 490 nm);

v) Plotting the absorbance curve as a function of the concentration of tungsten disulfide nanoparticles (measured from sample mass, initial concentration of nanoparticles in the composition, volume of cyclohexane added, and density of cyclohexane); Thus, the curve formed is a straight line representing the standard linear properties of the composition being tested;

vi) placement of test-tubes, 100 ml of composition and storage in ambient atmosphere;

vii) sampling the weighted mass and adding 20 ml of cyclohexane;

viii) measurement of absorbance (wavelength at 490 nm);

ix) measurement of the concentration of nanoparticles in the supernatant based on a standard straight line;

x) By repeating steps vi) to ix) at regular time intervals, the concentration of tungsten disulfide nanoparticles in the supernatant as a function of time can be measured.

The results are summarized in Table 3 and correspond to the mass concentration of tungsten disulfide nanoparticles in the supernatant phase; Results are expressed in mass %.

As the percentage increases, the resulting value approaches 1, and if the dispersion of tungsten disulfide nanoparticles in the lubricating oil composition is excellent, the stability of the lubricating oil composition is excellent.

9 to 15 d 29 to 35 d 49 to 55 d 100 d or more L ₁ 0.01 0.01 0 0 L ₂ 0.06 0.03 0.01 0.01 L ₃ 0.14 0.01 0.02 0.01 L ₄ 0.77 0.75 0.61 0.34 L ₅ 0.96 0.69 0.79 0.28

d = day

The result is that the lubricating oil composition according to the present invention L ₄ and L ₅ comprising 0.2% by weight of tungsten disulfide nanoparticles and a dispersing agent having a weight average molecular weight of 2000 Daltons or more, 0.2% by weight tungsten disulfide nanoparticles and a weight average of less than 2000 Dalton It has been shown that stability is improved with respect to a lubricating oil composition comprising a dispersant having a molecular weight.

It can be seen that the stability of the lubricating oil composition according to L ₄ and L ₅ of the present invention persists over time, but the stability of other compositions L ₁ , L ₂ and L ₃ does not persist.

Example 2: Evaluation of the friction properties of the lubricating oil composition according to the present invention

As the friction properties of the lubricant composition, the influence of the combination of tungsten disulfide nanoparticles and a dispersant having a weight average molecular weight of 2000 Daltons or more was determined by the Cameron Plint Friction laboratory test using a Cameron-Plint TE-77 type reciprocating tribometer. Is measured by

Thus, two lubricating oil compositions are prepared from the following compounds:

-Base oil 1: poly-alpha-olefin PAO 8 type base oil having a kinematic viscosity measured at 100° C. of 8 mm ² /s;

-Base oil 2: polyol ester (Priolube 3970 from Croda);

Polymer 1: Ethylene/propylene copolymer (Lucant HC600 from Mitsui Chemicals);

Polymer 2: poly alpha olefin (Spectrasyn 1000 from Exxon);

-Silicone-containing anti-foaming agents;

-A mixture of 20% tungsten disulfide nanoparticles as the active ingredient in oil (NanoLub Gear Oil Concentrate sold by Nanomaterials);

-Dispersant: PIB succinimide type dispersant according to the present invention having a weight average molecular weight measured according to standard ASTM D5296 of 6370 Da and a number average molecular weight measured according to standard ASTM D5296 of 2850 Da (OLOA 13000 from Oronite);

-Friction modifier: molybdenum dithiocarbamate (Molyvan 855 from Vanderbilt); And

-Additive package 1 containing a mixture of aminated antioxidants and phenolic antioxidants (Anglamol 2198 from Lubrizol).

Other lubricating oil compositions L ₆ to L ₇ are described in Table 4; The percentages indicated correspond to the mass percentages (%).

Composition L ₆
(Comparative example) L ₇
(Invention) Base oil 1 62.95 61.95 Base oil 2 15 15 Polymer 1 10 10 Polymer 2 5 5 Antifoam 0.05 0.05 Tungsten disulfide nanoparticles (Nanomaterials' NanoLub Gear Oil Concentrate) 2 Dispersant 2 Friction modifier 0.5 0.5 Additive Package 1 6.5 3.5 Kinematic viscosity at 100°C measured according to standard ASTM D445 (mm ² /s) 14.5 14.5

Composition L ₆ is a lubricating oil composition commonly used for lubricating transmissions and especially automotive gearboxes.

The kinematic viscosity at 100° C. of the compositions L ₆ and L ₇ can be equally adjusted in particular by the content of base oil 1 in order to compare the two compositions.

The coefficient of friction of each composition was evaluated by a Cameron Plint Friction laboratory test using a Cameron-Plint TE-77 type reciprocating tribometer. The test bench consists of a cylinder-on-flat tribometer immersed in the lubricant composition being tested. The coefficient of friction is monitored during the test by measuring the tangential force to the normal force. A cylinder (SKF 100C6) having a length of 100 mm and a length of 7 mm is applied to a steel flat immersed in the lubricating oil composition to be tested, and the temperature of the lubricating oil composition is set in each test. The sinusoidal reciprocating motion is applied at a determined frequency. Each measurement is performed at 100 second intervals during the test.

The average coefficient of friction values consisting of different temperatures, loads and speeds for each of the compositions L ₆ and L ₇ are shown in Table 5.

L ₆
(Comparative example) L ₇
(Invention) Average coefficient of friction at 60°C 0.087 0.082 Average coefficient of friction at 100°C 0.089 0.104 Average coefficient of friction under a load of 650 MPa 0.072 0.078

The average coefficient of friction at 60°C is measured under different loads of 300-650 MPa and different speeds of 70-550 mm/s.

The average coefficient of friction at 100°C is measured under different loads of 300-650 MPa and different speeds of 70-550 mm/s.

The average coefficient of friction at 640 MPa is measured under different temperatures of 60-140°C and different speeds of 70-550 mm/s.

The results show that the presence of a combination of tungsten disulfide nanoparticles according to the present invention and a dispersant having a weight average molecular weight of 2000 Daltons or more in a lubricating oil composition does not or only slightly alters the friction properties of the composition.

Example 3: Evaluation of peeling resistance of the lubricating oil composition according to the present invention

The peel resistance of the lubricating oil composition according to the present invention is evaluated by carrying out a test with a closed loop power circulation bench.

Thus, the lubricating oil composition L ₈ according to the invention and the composition L ₉ not according to the invention described in Table 6 are prepared; The percentages indicated correspond to the mass percentages (%).

Composition L ₈
(Invention) L ₉
(Comparative example) Base oil 1 62.45 62.45 Base oil 2 15 15 Polymer 1 10 10 Polymer 2 5 5 Antifoam 0.05 0.05 Tungsten disulfide nanoparticles (Nanomaterials' NanoLub Gear Oil Concentrate) 2 Dispersant 2 Additive Package 1 3.5 3.5 Additive Package 2 4

Base oil 1 and base oil 2, polymer 1 and polymer 2, antifoam, dispersant and additive package 1 are the same as described in Example 2.

Additive Package 2 (Anglamol 2190 from Lubrizol) contains zinc dithiophosphate as a friction modifier.

The closed loop power circulation bench is shown in FIG. 1.

The Renault JR5 gearbox is installed in the power circulation loop and placed under load by a torsion system, and the gearbox is coupled to the third gear.

The machine is operated using an electric motor to achieve a rotational speed of 300 rpm under a torque of 148 N.m at the gearbox input.

The evaluation criterion and the critical part to be evaluated are the drive pinion of the output shaft.

The gearbox is inspected at regular intervals of about 150 hours after dismantling and visual scoring. Visual scoring is performed using a "Chrysler" scoring system that monitors the presence of flakes with the teeth of the drive pinion and continuously vibrates to detect the gearbox delamination during operation.

The "Chrysler" scoring system displays the status of the teeth of the drive pinion after testing. Each tooth of the pinion is inspected to monitor whether it is peeling, and a score is assigned according to the degree of each peeling.

The scoring system is defined as:

-If the tooth's Flaking Surface (FS) is 0mm ² , Score = 0

-For FS ≤ 1 mm ² , Score = 0.4

-For 1 <FS ≤ 3 mm ² , Score = 1.3

-For 3 <FS ≤ 7 mm ² , Score = 4

-For 7 <FS ≤ 16 mm ² , Score = 12

-For 16 <FS <36 mm ² , Score = 36

-For FS ≥ 36 mm ² , Score = 108

The overall score is based on the following formula: 0.4 x A + 1.3 x B + 4 x C + 12 x D + 36 x E + 108 x F, where A, B, C, D, E and F are one and the same pinion Denote the number of teeth with the same level of degradation.

Vibration monitoring consists of placing an accelerometer close to the test piece and indicating the degree of vibration during operation. When the part is degraded, the vibration intensity increases. Thus, it is sufficient to stop the device and set it to a threshold to see if the teeth are flaking.

To prevent deterioration of pinions not connected to the lubricant, shaft bearings and third gear pinions are generally changed every 150 hours.

The test is stopped when flakes of up to 12 mm ² are observed and/or when a total exfoliated surface of 80 mm ² is observed and/or does not peel after 312 hours.

The test results obtained with the lubricating oil composition L ₈ are as follows:

-The test is carried out for 600 hours without any change of parts in the gearbox and no delamination of either the drive pinion or the third gear pinion is observed,

-No excess deposition of tungsten disulfide nanoparticles was observed in the housing.

The test for the lubricating oil composition L ₉ was stopped after 125 hours, and some flaking was observed.

Example 4: Evaluation of stability characteristics after use of the lubricating oil composition according to the present invention

After testing the closed loop power circulation bench, the risk of deposition of nanoparticles contained in the composition according to the present invention is measured.

Thus, the lubricating oil composition L ₁₀ according to the invention and the composition L ₁₁ not according to the invention, described in Table 7, are prepared, and the percentages indicated correspond to the mass percent (%).

Compositions L ₁₀
(Invention) L ₁₁
(Comparative example) Base oil 1 60.45 62.45 Base oil 2 15 15 Polymer 1 10 10 Polymer 2 5 5 Antifoam 0.05 0.05 Tungsten disulfide nanoparticles (Nanomaterials' NanoLub Gear Oil Concentrate) 4 4 Dispersant 2 Additive Package 1 3.5 3.5

Base oil 1 and base oil 2, polymer 1 and polymer 2, antifoam, dispersant and additive package 1 are the same as described in Example 2.

The test conditions are the same as described in Example 3.

2 shows that the excess deposit 200 of tungsten disulfide nanoparticles is not observed in the housing after testing with the composition L ₁₀ according to the present invention.

For composition L ₁₁ , FIG. 3 shows an excess deposit 300 of tungsten disulfide nanoparticles in the housing after testing with composition L ₁₁ , thus blocking lubricated holes of bearings or synchronizers. It can be dangerous.

Thus, the examples show that the lubricating oil composition according to the present invention has excellent stability over time and excellent peel resistance while maintaining satisfactory friction reduction properties.

Claims (19)

As a lubricant composition,
At least one base oil;
At least one dispersant having a weight-average molecular weight of 2000 Daltons or more and 0.1 to 10% by weight based on the total weight of the lubricating oil composition; And
Including; 0.01 to 2% by weight of metal nanoparticles based on the total weight of the lubricant composition,
The dispersant is selected from compounds containing at least one succinimide group,
The metal nanoparticles are concentric polyhedrons having a multilayer structure or a sheet structure,
Metal nanoparticles are represented by the formula MX _n , wherein M represents a transition metal, X represents a chalcogen, depending on the oxidation state of the transition metal M, n = 2 or n = 3 lubricating oil composition. The method of claim 1,
Metals constituting the metal nanoparticles are tungsten, molybdenum, zirconium, hafnium, platinum, rhenium, titanium, tantalum, and niobium. niobium), zinc, cerium, aluminum, indium and tin. The method of claim 1,
The metal nanoparticles are MoS ₂ , MoSe ₂ , MoTe ₂ , WS ₂ , WSe ₂ , ZrS ₂ , ZrSe ₂ , HfS ₂ , HfSe ₂ , PtS ₂ , ReS ₂ , ReSe ₂ , TiS ₃ , ZrS ₃ , ZrSe ₃ , HfS ₃ , HfSe ₃ , TiS ₂ , TaS ₂ , TaSe ₂ , NbS ₂ , NbSe ₂ and NbTe _{2 A} lubricating oil composition selected from the group consisting of. The method of claim 1,
The weight of the metal nanoparticles is 0.05 to 2% by weight based on the total weight of the lubricant composition, a lubricant composition. The method of claim 1,
The average size of the metal nanoparticles is 5 ~ 600nm, a lubricant composition. delete The method of claim 1,
The dispersant is selected from a compound containing at least one substituted succinimide group or a compound containing at least two substituted succinimide groups,
The lubricating oil composition, wherein the succinimide group is connected to a polyamine group at a carbon-containing vertex of the succinimide group having a nitrogen atom. The method of claim 1,
The weight average molecular weight of the dispersant is 2000 to 15000 Daltons, a lubricant composition. The method of claim 1,
The number-average molecular weight of the dispersant is 1000 Daltons or more, a lubricant composition. delete The method of claim 1,
The base oil is selected from poly alpha olefins or esters. The method of claim 1,
The lubricating oil composition further comprises at least one additional additive selected from polymeric viscosity index improvers and antioxidants or mixtures thereof,
The lubricating oil composition, wherein the polymer viscosity index improver is selected from ethylene and alpha-olefin copolymers. The method of claim 12,
The additional additive is an antioxidant selected from dialkylphenylamines, phenolic antioxidants, or mixtures thereof. A transmission oil comprising the lubricating oil composition according to any one of claims 1 to 5, 7 to 9, and 11 to 13. Lubrication of gearboxes or axles, comprising the use of a lubricating oil composition according to any one of claims 1 to 5, 7 to 9, 11 to 13 For the process. The method of claim 15,
The process, wherein the gearbox is a manual gearbox. Process for reducing delamination of mechanical parts, comprising the use of a lubricating oil composition according to any one of claims 1 to 5, 7 to 9 and 11 to 13. The method of claim 17,
The process, wherein the mechanical part is a gearbox. Tungsten disulphide nanoparticles in an amount of 1 to 15% by weight based on the total weight of the composition; And
Including; at least one dispersant having a weight average molecular weight of 2000 Daltons or more and 5 to 99% by weight based on the total weight of the composition,
The dispersant is an additive-concentrate type composition selected from compounds containing at least one succinimide group.

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