CN114945654A - Grease composition - Google Patents

Abstract

The invention provides a grease which is used for lubricating a mechanical element inserted into a reciprocating sliding ball and can keep the anti-stripping performance of the mechanical element inserted into the reciprocating sliding ball even under high load. Accordingly, the present invention provides a grease composition comprising a base oil (a), a diurea compound (b), an amide compound (c) and a thiophosphoric acid compound or a thiophosphoric acid ester compound (d),wherein the diurea compound (b) includes a compound R represented by the formula (1) ₁ ‑NHCONH‑R ₂ ‑NHCONH‑R ₃ (1) Wherein R is ₁ And R ₃ Represents an acyclic aliphatic hydrocarbon group having 8 to 20 carbon atoms, and R ₂ Represents a diphenylmethyl group.

Description

Grease composition

technical field

The present invention relates to a grease composition.

Background technique

The mechanical elements in which the reciprocating sliding balls are inserted include linear guides, ball screws, and constant velocity joints, and their use environments are various. Rolling and sliding of mechanical elements will occur simultaneously, and the lubrication environment will be harsh. Under these conditions, contact between the surfaces of the rolling elements tends to occur, and when contact is significant, wear or seizure can occur.

To prevent wear and seizure and to protect mechanical components, extreme pressure agents are often added to lubricants such as oils and greases. Well-known extreme pressure agents include sulfur-based extreme pressure agents, phosphorus-based extreme pressure agents, sulfur-phosphorus-based organic compounds, and molybdenum compounds. Among these extreme pressure agents, organic extreme pressure agents are particularly popular due to their excellent extreme pressure properties, and are currently widely used in lubricating oil compositions.

For example, JP200111481A discloses a grease composition for sliding constant velocity joints, the composition comprising a urea-based thickener, molybdenum sulfide dialkyl dithiocarbamate, molybdenum disulfide, sulfur-phosphorus group Extreme pressure agents such as zinc dithiophosphates or phosphorothioates and fatty acid amides to improve lubricity in parts prone to wear and may cause problems such as abnormal vibration. According to this document, the occurrence of induced thrust in the constant velocity joint will lead to problems such as reduced durability of the constant velocity joint, abnormal vibration of the vehicle, and reduced ride comfort. However, using the technology disclosed in this patent document can reduce wear and suppress vibration, Improve durability.

JP 2003321694A discloses a technique in which the grease composition contains a urea-based thickener and an organic sulfonate to prevent and prolong the spalling due to metal fatigue due to thinning of the oil film despite attempts to thicken the oil film service life.

JP200382374A discloses a technique in which a rolling bearing grease composition contains a urea-based thickener and benzotriazole and/or derivatives to prevent metal fatigue spalling due to thinning of the oil film despite attempts to thicken the oil film, and prolong Peeling service life.

JP2008239687A discloses a technique in which a bearing grease composition contains a urea-based thickener, an alkyl thiophosphate compound and an aliphatic amine.

JP201725189A discloses a technology in which the grease composition contains urea thickener, molybdenum dithiocarbamate, zinc dithiocarbamate and zinc sulfonate to prevent lubrication even under high speed/high surface pressure conditions metal-to-metal contact and form and maintain a film of friction-reducing additives.

The lubricant and grease compositions in JP200111481A, JP2003321694A, JP200382374, JP2008239687 and JP201725189A exhibit good wear resistance and film-forming ability under specific conditions or for specific mechanical elements, but stably maintain wear resistance during the process Compositions with an overall balance of film-forming ability have not yet provided reciprocating sliding under various high loads. In particular, the effect of reciprocating sliding on spalling under various high loads has not been studied and may not be sufficient.

In view of this situation, an object of the present invention is to maintain and improve mechanical parts even when rolling is temporarily stopped during reversal of reciprocating sliding, oil film cannot be sufficiently generated, metal-to-metal contact occurs, and frictional wear tends to be excessive service life. It is also an object of the present invention to form a strong additive film that stably maintains the formed film even after repeated operations, and provides stable lubricity. That is, an object of the present invention is to provide a grease composition which can be used for lubricating a mechanical element into which a reciprocating sliding ball is inserted, and which can maintain peeling resistance even under a high load.

SUMMARY OF THE INVENTION

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result found that a grease composition containing an amide compound, a phosphorothioate compound, or a phosphorothioate compound and a specific diurea compound can be used for a grease composition having a reciprocating sliding ball interposed therebetween. Mechanical elements to improve spalling resistance. The present invention is a product of this discovery. Specifically, the present invention is as follows.

Aspect (1) of the present invention is a grease composition comprising a base oil (a), a diurea compound (b), an amide compound (c), and a phosphorothioate compound or phosphorothioate compound (d) , wherein the diurea compound (b) includes a compound represented by the formula (1)

R ₁ -NHCONH-R ₂ -NHCONH-R ₃ (1)

Wherein, R ₁ and R ₃ represent an acyclic aliphatic hydrocarbon group having 8 to 20 carbon atoms, and R ₂ represents a diphenylmethane group.

Aspect (2) of the present invention is the grease composition according to aspect (1) of the present invention, wherein the diurea compound (b) includes a compound wherein R ₁ and R ₃ in Formula 1 have 8 to 12 carbon atoms Biurea compound (b) of an acyclic aliphatic hydrocarbon group or an acyclic aliphatic hydrocarbon group having 14 to 20 carbon atoms.

Aspect (3) of the present invention is the grease composition according to aspect (1) or (2) of the present invention, further comprising a saturated or unsaturated fatty acid having 4 to 18 carbon atoms or a metal salt (e) thereof.

The aspect (4) of the present invention is the grease composition according to any one of the aspects (1) to (3) of the present invention, which further contains the amine compound (f) represented by the formula (2).

R ₄ -NH-R ₅ -NH ₂ (2)

wherein R ₄ represents a saturated or unsaturated hydrocarbon group having 5 to 18 carbon atoms, and R ₅ represents a saturated or unsaturated hydrocarbon group having 2 to 3 carbon atoms.

The aspect (5) of the present invention is the grease composition according to any one of the aspects (1) to (4) of the present invention, wherein the amide-based compound (c) contains the compound represented by the formula (3). Amide compound (c) or formula (4)

R ₆ -CO-NH ₂ (3)

R ₆ -CO-NH-R ₇ -NH-CO-R ₆ (4)

wherein R ₆ represents a saturated or unsaturated alkyl group having 15 to 17 carbon atoms, and R ₇ represents a methylene group or an ethylene group.

(6) of the present invention is the grease composition according to any one of (1) to (5) of the present invention, wherein the thiophosphoric acid compound comprises a thiophosphoric acid compound represented by the formula (5), And the phosphorothioate compound includes a phosphorothioate compound represented by formula (6)

(R ₈ S) ₃ P(5)

(R ₉ O) ₃ PS (6)

wherein R ₈ represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, and wherein R ₉ represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or a 6 to aryl groups of 18 carbon atoms.

Description of drawings

FIG. 1 is a diagram showing an outline of a peeling resistance tester.

Detailed ways

The present invention can provide a grease composition that can be used for lubricating a mechanical element in which a reciprocating sliding ball is inserted, which maintains spalling resistance even under a high load.

In this application, "hydrocarbyl" refers to an atomic group obtained by removing a portion of hydrogen atoms from a hydrocarbon.

When the name of a compound appears in this application, that name includes all isomers of that compound.

In the present application, the amine compound forming the following diurea compound is referred to as the starting amine compound. The starting amine compound and the amine compound (f) may be the same or different. When referring to the amount of the amine compound (f) in this specification, the amount does not include the starting amine compound.

The grease composition of the present invention contains a base oil (a), a diurea compound (b), an amide compound (c), and a phosphorothioate compound or phosphorothioate compound (d).

The diurea compound (b) of the present invention includes the compound represented by the formula (1)

R ₁ -NHCONH-R ₂ -NHCONH-R ₃ (1)

wherein R ₁ and R ₃ represent an acyclic aliphatic hydrocarbon group having 8 to 20 carbon atoms, and R ₂ represents a diphenylmethane group.

The diurea compound (b) in the present invention is usually produced by reacting an isocyanate with a primary amine (starting amine compound). It will be appreciated that the morphology of the thickener fibers in the bisurea-based thickener depends on the combination of isocyanate and primary amine (starting amine compound), and the flow characteristics of the resulting grease composition vary widely.

It should be understood that the aliphatic urea-based grease using the diurea compound (b) of formula 1 as a thickener may be a urea-based grease consisting of alicyclic amine and aromatic amine or a urea-based grease consisting of aliphatic and/or aromatic amines A mixture of urea-based greases and these have different flow characteristics. It will also be appreciated that greases using the diurea compound (b) of formula 1 as thickeners tend to have excellent intervention properties at lubricating interfaces and play an important role in protecting mechanical elements. It should also be understood that greases using the biurea compound (b) in formula 1 as thickeners have good base oil solubility, intervene with the base oil at the lubricating interface, allowing the different flow patterns of the fibers to interact, providing good Flow behavior, imparting effective lubricity. It should also be understood that these effects are evident in aliphatic urea-based greases containing unsaturated fatty amines.

In addition, the grease composition of the present invention contains a diurea compound (b), an amide compound (c), a thiophosphite compound or a phosphorothioate compound (d), which has remarkable properties as described below For the effect of improving the peeling resistance, adding a fatty acid or fatty acid salt and an amine compound (f) different from the starting amine compound used to form the biurea compound (b) has further improved peeling resistance of the mechanical element. As a result, the mechanical element has a reciprocating sliding ball interposed therebetween.

It will also be appreciated that due to the excellent flow characteristics exhibited by the aliphatic diurea based thickeners in the fluid lubrication range where the reciprocating sliding speed is higher, the supply of the grease composition to the lubricating interface is improved, thereby having the advantage of thickening the lubricating film. effect, and, in addition to the lubricating film of the diurea compound (b), synergistic enhancement with urea-based grease due to the flow properties of the amide compound (c) and fatty acid or fatty acid salt (e) and the adsorption to metal surfaces The thickening effect further improves abrasion resistance. It should also be understood that in the mixed lubrication zone and boundary lubrication zone where the oil film is close to zero near the end of the reciprocating motion, due to the excellent flow characteristics of the grease, the thiophosphite compound contained in the grease composition that supplies the lubricating interface in large quantities. Or phosphorothioate compound (d) and amine compound (f) are adsorbed on the metal surface, and the strong coating formed at the interface due to tribochemical reaction has good anti-spalling properties.

The grease composition of the present invention contains a base oil (a). The base oil (a) used in the present invention is not particularly limited as long as the effects of the present invention are not impaired. The base oil (a) may be mineral oil, synthetic oil, animal oil or vegetable oil, or any mixture thereof. Specific examples are those of Groups 1 to 5 in the American Petroleum Institute (API) base oil category. API base oil categories are broad classifications of base oil materials as defined by the American Petroleum Institute to develop guidelines for lubricant base oils.

The mineral oil used in the present invention is not particularly limited. However, preferred embodiments include paraffin-based or naphthenic mineral oils that have been prepared by applying one or more refining methods such as solvent degassing, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrofinishing, Sulfuric acid scrubbing and clay treatment) applied to lubricating oil fractions obtained by atmospheric distillation and vacuum distillation of crude oil. These may be used alone or in combination of two or more.

The synthetic oil used in the present invention is not particularly limited. However, preferred examples include polyalpha-olefins (PAOs) and hydrocarbon synthetic oils (oligomers). PAO is an alpha-olefin homopolymer or copolymer. Alpha-olefins are compounds having a C-C double bond at the terminal, and specific examples include butene, butadiene, hexene, cyclohexene, methylcyclohexene, octene, nonene, decene, dodecene ene, tetradecene, hexadecene, octadecene and eicosene. Examples of hydrocarbon synthetic oils (oligomers) include ethylene, propylene and isobutylene homopolymers or copolymers. These may be used alone or in combination of two or more. These compounds may have any isomeric structure as long as they have a C-C double bond at the terminal, and may have a branched or linear structure. Also, two or more of these structural isomers and positional isomers having a double bond may be used in combination. Among these olefins, linear olefins having 6 to 30 carbon atoms are particularly preferably used because when the number of carbon atoms is five or less, the flash point is low, and when the number of carbon atoms is 31 or more, the viscosity is high and Olefins are not practical.

In the present invention, a base oil for gas liquefaction (GTL) is synthesized by using the Fischer-Tropsch process for converting natural gas into liquid fuel, which can be used as the base oil (a). Compared to mineral base oils refined from crude oil, GTL base oils have very low sulfur and aromatics content and a very high paraffin composition ratio. As a result, it has excellent oxidation stability and extremely low evaporation loss, and is very suitable for use as the base oil (a) in the present invention.

The grease composition of the present invention contains the biurea compound (b) represented by the formula (1)

R ₁ -NHCONH-R ₂ -NHCONH-R ₃ (1)

wherein R ₁ and R ₃ represent an acyclic aliphatic hydrocarbon group having 8 to 20 carbon atoms, and R ₂ represents a diphenylmethane group.

R ₁ and R ₃ may be any acyclic aliphatic hydrocarbon groups, and may be linear or branched chain saturated or unsaturated aliphatic hydrocarbon groups. R ₁ and R ₃ may have the same structure or different structures.

The diurea compound (b) of the present invention can be obtained by the reaction of the following formula (7).

NCO-R ₂ -OCN+R ₁ -NH ₂ +R ₃ -NH ₂ →R ₁ -NHCONH-R ₂ -NHCONH-R ₃ (7)

R ₁ and R ₃ are preferably an acyclic aliphatic hydrocarbon group having 8 to 12 carbon atoms or an acyclic aliphatic hydrocarbon group having 14 to 20 carbon atoms. More preferably, one of R ₁ and R ₃ is an acyclic aliphatic hydrocarbon group having 8 to 12 carbon atoms, and the other is an acyclic aliphatic hydrocarbon group having 14 to 20 carbon atoms. When R ₁ and R ₃ have these structures, a grease composition with better wear resistance and peeling resistance can be obtained.

The diurea compound (b) of the present invention may be used alone or in combination of two or more.

The grease composition of the present invention contains the amide compound (c). The amide compound (c) used in the present invention is not particularly limited as long as the effects of the present invention are not impaired. Preferred examples of the amide-based compound (c) that can be used in the present invention are aliphatic amide-based compounds represented by the following formula (3) or aliphatic bisamide-based compounds represented by the following formula (4). When the amide compound (c) has one of these structures, a grease composition having better wear resistance and peeling resistance can be obtained.

R ₆ -CO-NH ₂ (3)

R ₆ -CO-NH-R ₇ -NH-CO-R ₆ (4)

wherein R ₆ represents a saturated or unsaturated hydrocarbon group having 15 to 17 carbon atoms, and R ₇ represents a methylene group or an ethylene group.

Specific examples of aliphatic aliphatic amide compounds and aliphatic bisamide compounds include palmitic acid amide, palmitoleic acid amide, heptadecanic acid amide, stearic acid amide, oleic acid amide, octadecenoic acid amide, Linoleic acid amide, linolenic acid amide, eleuic acid amide, arachidic acid amide, eicosadienoic acid amide, meadic acid amide, arachidonic acid amide, erucic acid amide, behenic acid amide, methylene dipalmitide acid amide, methylene bis-palmitoleic acid amide, methylene bis-heptadecanoic acid amide, methylene bis-stearic acid amide, methylene bis-oleic acid amide, methylene bis-succinic acid amide, methylene Bislinoleic acid amide, methylenebislinolenic acid amide, methylenebisanthoic acid amide, ethylenebispalmitic acid amide, ethylenebispalmitoleic acid amide, ethylenebisheptadecanoic acid amide, ethylenebispalmitic acid amide Ethylbisstearic acid amide, ethylenebisoleic acid amide, ethylenebisoctadecenoic acid amide, ethylenebislinoleic acid amide, ethylenebislinolenic acid amide, and ethylenebistung oil acid amide. These may be used alone or in combination of two or more.

The grease composition of the present invention contains a phosphorothioate compound or phosphorothioate compound (d). The phosphorothioate compound or phosphorothioate compound (d) used in the present invention is not particularly limited as long as the effects of the present invention are not impaired. A phosphorothioate compound can also be combined with a phosphorothioate compound.

The phosphorothioate compound or phosphorothioate compound (d) used in the present invention is preferably a phosphorothioate compound represented by the following formula (5) or a phosphorothioate compound represented by the following formula (6). When the phosphorothioate compound or phosphorothioate compound has one of these structures, a grease composition having better wear resistance and peeling resistance can be obtained.

(R ₈ S) ₃ P(5)

R ₈ represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms.

(R ₉ O) ₃ PS (6)

R ₉ represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms.

Specific examples of the phosphorothioate compound and phosphorothioate compound (d) include alkyl phosphorothioates such as trilauryl trithiophosphite and aromatic phosphorothioates such as triphenyl phosphorothioate. When an alkylthiophosphite is used, a grease composition with better abrasion resistance and spalling resistance can be obtained. These may be used alone or in combination of two or more.

The grease composition of the present invention may further contain any of the following components. When the grease composition of the present invention contains fatty acid or its metal salt (e) or amine compound (f), better abrasion resistance and peeling resistance can be obtained. When the grease composition of the present invention contains the fatty acid or its metal salt (e) and the amine compound (f), even better abrasion resistance and peeling resistance can be obtained.

The grease composition of the present invention may contain a fatty acid or its metal salt (e). The fatty acid or its metal salt (e) used in the present invention is not particularly limited as long as the effects of the present invention are not impaired. The fatty acid or its metal salt used in the present invention is preferably a saturated or unsaturated fatty acid or its metal salt having 4 to 18 carbon atoms. When the grease composition of the present invention contains fatty acid or its metal salt (e), even better abrasion resistance and peeling resistance can be obtained.

Specific examples of fatty acids include butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, nonanoic acid, capric acid, lauric acid, myristic acid, pentadecanoic acid, palmitic acid, mandelic acid, stearic acid, crotonic acid , myristic acid, palmitoleic acid, sapienoic acid, oleic acid, linoleic acid, linolenic acid, pinocolic acid, stearidonic acid, stearidonic acid and eicosapentaenoic acid. These may be used alone or in combination of two or more. Since unsaturated fatty acids are more easily adsorbed on metal surfaces than saturated fatty acids, they are preferable from the viewpoint of obtaining a grease composition having excellent abrasion resistance and peeling resistance. As for the number of carbon atoms, a larger number of carbon atoms is more preferable. Oleic acid is one example of such a fatty acid.

Metal elements used to form salts with these fatty acids are not particularly limited as long as the effects of the present invention are not impaired. Specific examples of metal elements include alkali metals such as lithium, sodium, potassium, rubidium, and cesium; beryllium; magnesium; alkaline earth metals such as calcium, strontium, and barium; aluminum; and zinc. These may be used alone or in combination of two or more. Among them, calcium salts and aluminum salts are preferred from the viewpoint of obtaining a grease composition having excellent wear resistance and peeling resistance.

The grease composition of the present invention may contain the amine compound (f). The amine compound (f) used in the present invention is not limited as long as the effects of the present invention are not impaired. The amine compound (f) used in the present invention is preferably an amine compound represented by the following formula 2. When the grease composition of the present invention contains such an amine compound, even better wear resistance and peeling resistance can be obtained.

R ₄ -NH-R ₅ -NH ₂ (2)

R ₄ represents a saturated or unsaturated hydrocarbon group having 5 to 18 carbon atoms, and R ₅ represents a saturated or unsaturated hydrocarbon group having 2 to 3 carbon atoms.

Specific examples of the amine compound (f) include N-coconut alkyl-1,2-ethylenediamine, N-tallow alkyl-1,2-ethylenediamine, N-hardened tallow alkyl-1,2 -Ethylenediamine, N-Coconut alkyl-1,3-propanediamine, N-tallow alkyl-1,3-propanediamine, N-hardened tallow alkyl-1,3-propanediamine, N-coconut alkyl-1,3-propanediamine, N-tallow alkyl-1,3-propanediamine, N-hardened tallow alkyl-1,3-propanediamine, N-coconut alkane Alkyl-1,4-butanediamine, N-tallowalkyl-1,4-butanediamine and N-hardened tallowalkyl-1,4-butanediamine. These may be used alone or in combination of two or more. Among these, N-tallow alkyl-1,3-propanediamine is preferred from the viewpoint of obtaining a grease composition having excellent wear resistance and peeling resistance.

The grease composition of the present invention may contain a thickener (other thickener) other than the urea compound in addition to the above-mentioned (urea-based) thickener. Examples of other thickeners include tricalcium phosphate, alkali metal soaps, alkali metal complex soaps, alkaline earth metal soaps, alkaline earth metal complex soaps, alkali metal sulfonates, alkaline earth metal sulfonates, other metal soaps, terephthalic acid Metal salts, monoureas, polyureas other than triurea monourethane, diurea, or tetraurea, clays, silica (silicon dioxide) such as silica aerogels, and fluororesins such as polytetrafluoroethylene vinyl. These may be used alone or in combination of two or more. In addition to these thickeners, any substance that imparts a viscous effect to a liquid substance can be used. When any of the fatty acids or their metal salts (e) described above are used, the fatty acids or their metal salts (e) may double as a thickening agent. When the fatty acid or its metal salt (e) doubles as a thickener, the amount used may be different from that of the above-mentioned fatty acid or its metal salt (e).

The grease composition of the present invention may contain antioxidants, rust inhibitors, oily agents, extreme pressure agents, antiwear agents, solid lubricants, metal deactivators, polymers, non-metallic cleaners, colorants, water repellants, and the like Additives, as long as they do not impair the present invention. These may be used alone or in combination of two or more.

Examples of antioxidants include 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-p-cresol, p,p'-dioctyldiphenylamine, N-phenyl-alpha - Naphthylamines and phenothiazines.

Examples of rust inhibitors include oxidized paraffin, metal carboxylate, metal sulfonate, carboxylate, sulfonate, salicylate, succinate, sorbitan ester, and various amine salts.

Examples of oily agents, extreme pressure agents, and antiwear agents include sulfurized zinc dialkyldithiophosphate, sulfurized zinc diallyl dithiophosphate, sulfurized zinc dialkyldithiocarbamate, sulfurized diallyl dithiocarbamate, molybdenum sulfide dialkyl dithiophosphate, molybdenum sulfide diallyl dithiophosphate, molybdenum sulfide dialkyl dithiocarbamate, molybdenum sulfide diallyl dithiocarbamates, organomolybdenum complexes, olefin sulfides, triphenyl phosphite, triphenyl thiophosphate, triresin phosphite, other phosphates and sulfurized greases.

Examples of solid lubricants include molybdenum disulfide, graphite, boron nitride, melamine cyanurate, polytetrafluoroethylene (PTFE), tungsten disulfide, and graphite fluoride. Examples of metal deactivators include N,N'-disalicylidene-1,2-diaminopropane, benzotriazole, benzimidazole, benzothiazole, and thiadiazole. Examples of polymers include polybutene, polyisobutene, polyisobutylene, polyisoprene, and polymethacrylate.

One example of a non-metallic cleaner is succinimide.

The production method of the grease composition of the present invention is not particularly limited. However, the grease composition of the present invention can be prepared by weighing the respective raw materials and mixing them together using any known method. As for the amount of optional components added, the above-mentioned amounts may be used as required.

The base oil (a) is preferably used in an amount of 70 to 98% by mass, more preferably 75 to 97% by mass, and further preferably 80% by mass relative to 100% by mass of the total grease composition to 95%.

The amount of the biurea compound (b) used in the present invention is preferably 1 to 25% by mass, more preferably 3 to 20% by mass, further preferably 100% by mass of the total grease composition 5 to 15% by mass. When a thickener other than the diurea compound (b) is added, the total amount of the diurea compound (b) and the thickener other than the diurea compound (b) relative to 100% by mass of the total grease composition The amount is preferably 2 to 50% by mass, more preferably 4 to 40% by mass, even more preferably 6 to 30% by mass. When the amount of the diurea compound (b) is within this range, the grease composition has hardness suitable for grease, does not flow out from the lubricated portion, has excellent intervention performance at the lubricating interface, and obtains desired lubricating performance.

The amide compound (c) in the present invention is used in an amount of preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, further preferably 0.2 to 5% by mass relative to 100% by mass of the total grease composition 0.3 to 3% by mass.

The amount of the phosphorothioate compound or phosphorothioate compound (d) used in the present invention is preferably 0.1 to 10% by mass, more preferably 0.1 to 10% by mass with respect to 100% by mass of the total grease composition 0.2 to 5%, more preferably 0.3 to 3% by mass.

The fatty acid or its metal salt (e) in the present invention is used in an amount of preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, relative to 100% by mass of the total grease composition, It is further preferably 0.3 to 3% by mass.

The amount of the amine compound (f) used in the present invention is preferably 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, further preferably 0.2 to 5% by mass relative to 100% by mass of the total grease composition 0.3 to 3% by mass.

The amount of any additional additives used is preferably 0.1 to 20 parts by mass per 100 parts by mass of the overall grease composition.

The consistency of the grease composition of the present invention ranges from No. 2 to No. 0 (265 to 385), preferably No. 4 to No. 00 (175 to 430), more preferably No. 3 to No. 0 (220 to 385), even more preferably 2 to 1 (265 to 340). Consistency indicates the physical hardness of the grease. The method for measuring the consistency here is in accordance with JIS K2220 7 in "Grease Consistency Test Method".

The dropping point is not related to the performance of the grease composition of the present invention, but is preferably 180°C or higher as an index for achieving the original binding force of the urea grease thickener structure. The dropping point is the temperature at which the grease loses its thickener structure as the temperature increases. The measurement method of the dropping point is "Grease Dropping Point Measurement Method" in JIS K22208.

The grease composition of the present invention can naturally be used for machinery, bearings, gears, ball screws, etc., and can exhibit excellent grease lubricating performance even in severe environments. It is suitable for lubricating a variety of automotive components, including those around the engine such as water pumps, cooling fan motors, starters, alternators and actuators, as well as driveshafts, constant velocity joints (CVJs), powertrain components such as wheels Bearings and clutches, electric power steering (EPS) assemblies, power window assemblies, brakes, ball joints, door hinges, handle assemblies and brake extenders. The grease composition of the present invention is preferably used in construction machinery such as excavators, bulldozers, mobile cranes, steel industry, paper industry, forestry machinery, agricultural machinery, in chemical plants, power generation facilities and railway cars. Other applications include seamless pipe and threaded joints for outboard motor bearings. The grease compositions of the present invention are particularly suitable for these applications.

Description of drawings

FIG. 1 is a diagram showing an outline of a peeling resistance tester. The following sections are marked as follows:

1: Motor

2: Rotary axis

3: Crank arm (1)

4: Strain gauge

5: Crank bending part

6: Crank arm (2)

7: Install the fixing nut

8: Key Materials

9: Cone fitting part

10: Nut

11: Collar

12: Bearing stop

13: Test rolling bearings

14: Bearing unit

15: Load control device

16: Auxiliary rolling bearing

17: Swing axis

Example

The following is a more detailed description of the present invention with reference to Examples and Comparative Examples. Note, however, that the present invention is not limited to these examples in any way.

Raw material composition

The following raw material components were used in Examples and Comparative Examples.

Base oil (a)

• Base oil A: a mineral oil having a kinematic viscosity of 99.05 mm ² /s at 40°C and 11.13 mm ² /s at 100°C.

• Base oil B: a mineral oil having a kinematic viscosity of 480.2 mm ² /s at 40°C and 31.56 mm ² /s at 100°C.

Base Oil C: A highly refined oil with a dynamic viscosity of 43.88 ^mm2 /s at 40°C and 7.774 ^mm2 /s at 100°C, a viscosity index of 146 and a % CA of 1 or Even lower, the %CN was 11.9 and the %CP was 85 or more.

• Base oil D: a polyalpha-olefin oil having a kinematic viscosity of 396.5.3 mm ² /s at 40°C and a kinematic viscosity of 39.99 mm ² /s at 100°C.

• Base oil E: an alkyl diphenyl ether oil having a kinematic viscosity of 102.2 mm ² /s at 40°C and 12.64 mm ² /s at 100°C.

Diurea compound (b)

The biurea compound (b) was prepared by reacting the following raw materials using the preparation method described below.

· Diurea Compound A:

Diphenylmethane-4,4'-diisocyanate (MDI)

Octylamine

oleylamine

· Diurea Compound B:

Diphenylmethane-4,4'-diisocyanate (MDI)

Octylamine

Amide compound (c)

·Amide compound A: oleic acid amide (oleic acid amide from Japanese Lion Chemicals)

· Phosphorothioate compounds and phosphorothioate compounds (d)

Thiophosphoric acid compound A: Trilauryl trithiophosphite (JPS-312 from Johoku Chemical Industry, Japan)

Phosphorothioate Compound A: Triphenylphosphorothioate (Irgalube TPPT from BASF)

Fatty acid or its metal salt (e)

Fatty acid A: oleic acid (NAA-35 from NOF)

Fatty acid metal salt A: calcium stearate (calcium stearate GP from NOF)

Fatty acid metal salt B: aluminum stearate (aluminum stearate 300 from NOF)

Amines (f)

·Amine compound A: N-tallow alkyl-1,3-propanediamine (Lipomin DA-T from Japan Lion King Chemical Co., Ltd.)

Example 1

After the base oil and MDI are heated in the container to dissolve the contents, the raw material mixture obtained by dissolving and mixing octylamine, oleylamine and the base oil is added to the container to react and synthesize the biurea compound A. The temperature was raised to 170°C with stirring and maintained at this temperature for about 30 minutes to complete the reaction. Then, the mixture was rapidly frozen, various additives were added in the proportions shown in Table 1 during the cooling process, mixed with stirring, cooled to 80° C., and passed through a homogenizer to obtain grease.

Examples 2-18, Comparative Examples 1-5

A grease composition was prepared in the same manner as in Example 1, except that the raw materials mixed together were as shown in Tables 1 to 4. Biurea Compound B was prepared by changing the starting materials in Biurea Compound A to those listed above.

Evaluation of Grease Compositions

The following measurements and tests were performed in order to compare the characteristics and performances of the Examples and Comparative Examples.

According to "Grease Consistency Test Method" in JIS K2220 7, the working penetration and the non-working penetration of the grease compositions in Examples and Comparative Examples were measured. The results are shown in Tables 1 to 4 below.

According to "Grease Dropping Point Test Method" in JIS K2220 8, the dropping points of the grease compositions in Examples and Comparative Examples were measured. The results are shown in Tables 1 to 4 below.

In bearing spalling and wear testing, the grease compositions of the Examples and Comparative Examples were evaluated for wear resistance and spalling resistance. The results are shown in Tables 1 to 4 below. The following is an explanation of the evaluation method. FIG. 1 is a schematic diagram showing a bearing peeling wear tester. The weight of a clean test rolling bearing (No. 7205 angular contact ball bearing) was measured in advance, and 3 g of the grease composition was applied to the bearing and loaded into a bearing spall wear tester. Then, the nut of the swing shaft is fixed with a tightening torque of 600 kg·m, and a thrust load is applied to the shaft by the tightening torque. Next, a hydraulic piston is used to apply a radial load of 1.0 tons to each bearing. The motor starts, and the swing shaft reciprocates at a frequency of 1.7Hz. After the swing operation for 20 hours, the bearing was taken out from the apparatus and washed with a solvent such as n-hexane to completely remove the grease composition. Measure the weight of the clean bearing after the test, calculate the weight difference relative to the weight of the bearing before the test, and obtain the bearing wear amount. The amount of bearing wear after the test and the areas of the sliding surfaces of the inner and outer rings where spalling occurred were measured to evaluate whether the grease composition was acceptable. The pass/fail decision is based on the area where spalling occurred. When the area is less than 50 mm ² , the grease composition is acceptable. When the area is larger, the grease composition fails. The area where peeling occurred was determined by observing under a digital microscope (VHX-6000 from KEYENCE) and specifying the part where peeling occurred, and then measuring the area.

Test Conditions

Test bearing: No. 7205 (angular ball bearing)

Grease amount: 3.0g

Oscillation: 1.7Hz

Thrust load: 600Kg m

Radial load: 1.0 tons

Temperature: 25℃

Time: 20 hours

evaluation result

Working penetration, dropping point, and bearing spalling and wear tests were performed according to the methods described above. The properties of each grease are shown in Tables 1 to 4 below. The grease compositions in the Examples had a consistency of No. 0 to 2, and the grease compositions of the Comparative Examples had a consistency of No. 2 to 2.5. The dropping points of the grease compositions of Examples and Comparative Examples at 240° C. or higher are comparable to those of urea greases. Results The most important aspect of the present invention is the bearing peeling and wear test. All the grease compositions of the present invention passed the test, the wear bearing amount was less than 150 mg, and the total peeling area was less than 50 mm ² . In the case of the grease composition in the comparative example, the bearing wear amount bearing peeling and the wear test were remarkable, and the total peeling area of the sliding surfaces of the inner ring and the outer ring exceeded 50 mm ² , and the test failed.

Table 1

Table 2

table 3

Table 4

Claims (6)

1. A grease composition comprising a base oil (a), a diurea compound (b), an amide compound (c), and a thiophosphoric acid compound or a thiophosphate compound (d), wherein the diurea compound (b) includes a compound represented by formula (1)

R ₁ -NHCONH-R ₂ -NHCONH-R ₃ (1)

Wherein R is ₁ And R ₃ Represents an acyclic aliphatic hydrocarbon radical having 8 to 20 carbon atoms, and R ₂ Represents a diphenylmethyl group.

2. The grease composition according to claim 1, wherein the diurea compound (b) comprises R in formula 1 ₁ And R ₃ A diurea compound (b) which is an acyclic aliphatic hydrocarbon group having 8 to 12 carbon atoms or an acyclic aliphatic hydrocarbon group having 14 to 20 carbon atoms.

3. A grease composition according to claim 1 or 2, further containing a saturated or unsaturated fatty acid having 4 to 18 carbon atoms or a metal salt thereof (e).

4. The grease composition according to any one of claims 1 to 3, further comprising an amine compound (f) represented by formula (2)

R ₄ -NH-R ₅ -NH ₂ (2)

Wherein R is ₄ Represents a saturated or unsaturated hydrocarbon group having 5 to 18 carbon atoms, and R ₅ Represents a saturated or unsaturated hydrocarbon group having 2 to 3 carbon atoms.

5. The grease composition according to any one of claims 1 to 4, wherein the amide-based compound (c) comprises an amide-based compound (c) represented by formula (3) or formula (4)

R ₆ -CO-NH ₂ (3)

R ₆ -CO-NH-R ₇ -NH-CO-R ₆ (4)

Wherein R is ₆ Represents a saturated or unsaturated alkyl group having 15 to 17 carbon atoms, and R ₇ Represents a methylene group or an ethylene group.

6. A grease composition according to any one of claims 1 to 5, wherein the thiophosphoric acid compound comprises a thiophosphoric acid compound represented by formula (5) and the thiophosphate compound comprises a thiophosphate compound represented by formula (6)

(R ₈ S) ₃ P(5)

(R ₉ O) ₃ PS (6)

Wherein R is ₈ Represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms, andin R ₉ Represents a saturated or unsaturated hydrocarbon group having 8 to 18 carbon atoms or an aryl group having 6 to 18 carbon atoms.

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