Oil leak sealant composition, lubricating oil composition containing said oil leak sealant composition, and method of using the oil leak sealant composition

Abstract

To provide an oil leak prevention agent composition which imparts swelling property to a sealing material provided in a lubrication system, and can maintain sealing property, and a method for using the same.SOLUTION: There are provided an oil leak prevention agent composition for use as a component of a lubricant composition and a method of using the same. The oil leak prevention agent composition comprises at least a component A and a component B, the component A contains a polyol ester of trimellitic anhydride, and the component B contains at least one compound selected from a group consisting of (a) sulfolane having a substituent and (b) hydrocarbon group-substituted thiophene.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an oil leak stopper composition, a lubricating oil composition containing the oil leak stopper composition, and a method for using the oil leak stopper; more specifically, the present invention relates to an oil leak stopper composition used as an additive for lubricating oils for internal combustion engines, lubricating oils for electric vehicle drives, lubricating oils for automatic transmissions, gear oils, turbine oils, etc.; a lubricating oil composition containing the oil leak stopper composition; and a method for using the oil leak stopper composition to maintain the sealing performance caused by swelling of seals installed in lubrication systems. [Background technology]

[0002] Conventionally, in order to improve the performance of lubricating oils, various additives are blended into mineral oil and / or synthetic oil lubricating base oils, although the types vary depending on the application. Examples of such additives include antioxidants, antiwear agents, friction reducers, ashless dispersants, metal detergents, viscosity index improvers, pour point depressants, antifoaming agents, etc. Such additives are usually used as an additive package in which various additives are combined. On the other hand, in a lubrication system where lubricating oil containing such additives is used, a large number of seals are usually used between connecting parts in the form of O-ring seals, gasket seals, piston seals, etc. Material Examples of such materials include fluoroelastomer rubber (Viton (registered trademark)), polytetrafluoroethylene elastomer (PTFE), silicone rubber, polyacrylate rubber, and nitrile butadiene rubber. Although many of the lubricating oil's performances can be improved by blending the lubricating base oil and additives, MaterialIt has been pointed out that problems with compatibility with lubricating base oils can occur, and that when lubricating base oils come into contact with highly refined base oils, such as non-polar base oils obtained by hydrocracking or hydrotreating, the rubber seals mentioned above can harden or shrink, and that contact with additives can further increase shrinkage. If the seal shrinks, gaps will form on the connecting surfaces, causing the lubricating oil to leak, which will result in problems with the operation of engines and other devices. Under these circumstances, the use of seal swelling additives that have the effect of swelling the sealing material has been proposed, and phthalate esters, for example, are known. Patent Document 1 describes the results of using an aliphatic amine as a swelling agent for a sealant. Furthermore, according to Patent Document 2, organic acid esters such as sorbitol esters are also proposed as seal swelling agents. However, the change in hardness of rubber seals caused by the use of such seal swelling agents has not been fully investigated, and the change in hardness is large in the positive direction, so the swelling properties are still insufficient and there is still room for improvement in the sealing properties. Therefore, there has been a strong demand for the development of an oil leak stopper that has a relatively small positive change in hardness of the sealing material compared to lubricating oil without the oil leak stopper added, improves swelling properties, and provides excellent sealing effect. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-181461 [Patent Document 2] Special Publication No. 2015-503673 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, the first object of the present invention is to provide an oil leak stopper composition that can maintain sealing performance and prevent lubricating oil from seeping out of a lubricating system by imparting swelling properties to the sealing material in the lubricating system, and second object of the present invention is to provide a method for using the oil leak stopper to maintain the sealing performance of the sealing material in the lubricating system of an engine. [Means for solving the problem]

[0005] Therefore, in order to solve the above-mentioned problems of the present invention, the present inventors have analyzed the conventional ester-based seal swelling agents and have conducted extensive research into improvements. Material The present inventors have focused on an ester component that is highly compatible with the chemical structure of the compound (II) and have further noted that the combination of such an ester component with a heterocyclic structural component imparts appropriate swelling properties to the sealing material, and that the above-mentioned problems can be solved by balancing the high molecular weight component with excellent sealing effect and the low molecular weight component with excellent penetration ability into narrow spaces. Based on this knowledge, the present inventors have arrived at the present invention.

[0006] Thus, the gist of the present invention is as shown in the following (1) to (9). (1) An oil leak stopper composition for use as a component of a lubricating oil composition, comprising: An oil leak stopper composition comprising at least component A and component B, The component A contains a polyol ester of trimellitic anhydride, The component B is (a) a substituted sulfolane, and (b) Hydrocarbon-substituted thiophenes An oil leak stopper composition comprising at least one compound selected from the group consisting of: (2) The oil leak stopper composition according to (1) above, wherein component C is further blended with component A and component B. (3) The oil leak stopper composition according to (2), wherein the component C is a base oil and at least other additives that constitute the oil leak stopper composition. (4) The oil leak stopper composition according to (1), wherein the content of Component A and the content of Component B are 0.1 to 30 mass% and 0.05 to 20 mass%, based on the total mass of the oil leak stopper composition. (5) The oil leak stopper composition according to (1) above, wherein the mixing ratio of Component A to Component B is in the range of 0.05 to 5 parts by mass of Component B relative to 1 part by mass of Component A. (6) A lubricating oil composition comprising a lubricating base oil, the oil leak stopper composition according to any one of (1) to (5) blended into the lubricating base oil, and at least one other lubricating oil additive composition selected arbitrarily. (7) The lubricating oil composition according to (6) above, wherein the blending amount of the oil leak stopper composition in the lubricating oil composition is 1 to 30 mass % based on the total mass of the lubricating oil composition. (8) The lubricating oil composition according to (6) above, which is used for lubricating oils for internal combustion engines, lubricating oils for hybrid vehicles, lubricating oils for electric vehicles, lubricating oils for automatic transmissions and continuously variable transmissions, and other drive system lubricating oils. (9) A method for using an oil leak stopper, characterized in that an effective amount of the oil leak stopper composition described in (1) to (5) is blended with a lubricating oil composition, and the resulting novel lubricating oil composition is poured into a lubrication system, or the oil leak stopper composition described in (1) to (5) is added to the lubricating oil in the lubrication system, thereby maintaining the sealing performance of a seal material in the lubrication system. [Effects of the Invention]

[0007] By incorporating the oil leak stopper composition of the present invention, it is possible to impart sufficient swelling properties to seal materials such as fluoropolymer elastomer (FRM), nitrile butadiene rubber (NBR), and acrylic rubber (ACM) to maintain their sealing properties. In particular, when the polyol ester of trimellitic anhydride (Component A) and the substituted sulfolane (Component B) that constitute the oil leak stopper composition are used in combination, a remarkable effect is achieved with respect to rubber swelling properties that improve both the volume change rate and hardness change, and the absence of either Component A or Component B makes it impossible to achieve the desired effect, as will be shown in the Examples and Comparative Examples described below. As will be shown in the Examples and Comparative Examples described below, the combined use of Component A and Component B, particularly in a specific ratio, produces an unexpected effect of achieving significantly remarkable swelling properties. BEST MODE FOR CARRYING OUT THE INVENTION

[0008] Oil leak stopper composition The oil leak stopper composition of the present invention comprises at least component A and component B, The component A contains a polyol ester of trimellitic anhydride, The component B is (a) a substituted sulfolane, and (b) Hydrocarbon-substituted thiophenes The compound contains at least one compound selected from the group consisting of:

[0009] Ingredient A Polyol ester of trimellitic anhydride : The polyol ester of trimellitic anhydride, component A constituting the oil leak stopper composition of the present invention, contains at least one compound selected from the group consisting of compounds represented by the following formulas (1-1) and (1-2): [ka] In the formula (1-1), X is a divalent alkenyl group having 2 to 12 carbon atoms. [ka] In the formula (1-2), R is a group selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 3 carbon atoms. In the formula (1-1), the (-OXO-) group is derived from a group of saturated aliphatic hydrocarbons, and X is composed of the backbone atoms that constitute the polyol between both terminal hydroxyl groups.

[0010] In the formula (1-1), X is a divalent alkenyl group having 2 to 12 carbon atoms, and in the formula (1-2), R is selected from a hydrogen atom and an alkyl group having 1 to 3 carbon atoms. Specific examples of the alkenyl group having 2 to 12 carbon atoms include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl, and the like, and isomers thereof. Furthermore, examples of the alkyl group having 1 to 3 carbon atoms represented by R include methyl, ethyl, propyl, and isomers of propyl. The compounds of the formulae (1-1) and (1-2) may be produced by any method, but it has been proposed to produce them by reacting trimellitic anhydride with an organic acid ester of an alkane polyol. The alkane polyol preferably has a terminal hydroxyl group and has 1 to 12 carbon atoms. Specific examples include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and 1,12-dodecanediol. Alkane polyols having three hydroxyl groups can also be used. Examples include glycerol, trimethylolpropane, and triethylolpropane. Also included are tetrahydroxyalkane polyols such as pentaerythritol. In the polyol ester of trimellitic anhydride suitable as component A of the oil leak stopper composition of the present invention, X in general formula (1-1) is selected so as to have the following kinematic viscosity: Preferred polyols can be selected from the group consisting of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,8-octanediol. Furthermore, R in the general formula (1-2) can be selected from a hydrogen atom or a methyl group.

[0011] Component A, which constitutes the oil leak stopper composition of the present invention, is a fluid containing a polyol ester of trimellitic anhydride as described above, and belongs to API Category Group V fluids. The viscosity is preferably a kinematic viscosity at 40°C of 280 to 360 mm2 / s and a kinematic viscosity at 100°C of 18 to 25 mm2 / s. A viscosity index of 70 or higher can also be used. The PALUB series is a commercially available product containing such a polyol ester.

[0012] Component B Substituted sulfolanes: The sulfolane having a substituent specified as a component of the oil leak stopper composition of the present invention has the following general formula (2): [ka] Preferred are those containing substituted sulfolane represented by the following formula: In formula (1), R1 is a hydrocarbon group having 4 or more carbon atoms, and examples thereof include aliphatic groups such as alkyl groups and alkenyl groups, alicyclic groups such as cycloalkyl groups and cycloalkenyl groups, aromatic groups, aliphatic- and alicyclic-substituted aromatic groups, and aromatic-substituted aliphatic and alicyclic groups. Examples thereof include butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyldecyl, eicosyl, decenyl, cyclohexyl, phenyl, tolyl, heptylphenyl, isopropenylphenyl, and naphthyl groups, as well as isomers thereof. Substituted sulfolane suitable for component B of the oil leak stopper composition of the present invention is one in which R1 is a hydrocarbon group having 4 to 50 carbon atoms, and specific examples of hydrocarbon groups that may be selected include butyl, pentyl, hexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, triacontanyl, butenyl, dodecenyl, phenyl, naphthyl, tolyl, dodecylphenyl, tetrapropene-alkylated phenyl, phenethyl, cyclohexyl, and methylcyclohexyl (the hydrocarbon groups also include their respective isomers). Among these hydrocarbon groups, alkyl or alkenyl groups having 4 to 30 carbon atoms ( different (including the cis- and trans-forms) is preferred. In addition, in formula (1), X is preferably an oxygen atom or a sulfur atom. R2 and R3 are each selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 4 carbon atoms.

[0013] Substituted sulfolane more suitable as component B of the oil leak stopper composition of the present invention is one in which R1 is a mixture of butyl, pentyl, hexyl, and other groups having 4 to 12 carbon atoms, or an alkyl group or branched alkyl group such as decyl or isodecyl. Furthermore, R2 and R3 are each preferably a hydrogen atom, and X is preferably an oxygen atom or a sulfur atom. From this perspective, the substituent is preferably one having a 3-alkoxy group or a 3-alkthio group. Additives containing sulfolane having the above-mentioned substituents are commercially available.

[0014] Hydrocarbon-substituted thiophenes : The hydrocarbon group-substituted thiophene used as component B of the oil leak stopper composition of the present invention is a derivative in which a hydrogen atom in thiophene is replaced with a hydrocarbon group, and a specific example thereof is a compound having the following general formula (3): [ka] In formula (3), R4 is a hydrocarbon group, and examples of the hydrocarbon group include aliphatic groups such as alkyl groups or alkenyl groups, alicyclic groups such as cycloalkyl groups or cycloalkenyl groups, aromatic groups, aliphatic- and alicyclic-substituted aromatic groups, and aromatic-substituted aliphatic and alicyclic groups. Specific examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, eicosyl, decenyl, cyclohexyl, phenyl, tolyl, heptylphenyl, isopropenylphenyl, and naphthyl groups, as well as isomers thereof. In the hydrocarbon-substituted thiophene suitable as component B of the oil leak stopper composition of the present invention, R4 is a hydrocarbon group having 1 to 50 carbon atoms, and specific examples thereof include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, eicosyl, butenyl, hexenyl, octenyl, decenyl, dodecenyl, phenyl, phenethyl, cyclohexyl, methylcyclohexyl, and the like, as well as isomers thereof. In formula (3), the number n of substituents may be 1 or more and 4 or less, but is preferably 1 or 2. The substitution position on the five-membered ring may be any position, but is preferably 2 or 3. From the above viewpoints, the hydrocarbon-substituted thiophene more suitable as component B of the oil leak stopper composition according to the present invention is one in which R4 is an alkyl or alkenyl group having 1 to 10 carbon atoms or an isomer thereof, and particularly preferably one having 4 to 10 carbon atoms, specifically an alkyl group such as a butyl group, a hexyl group, an octyl group, or a decyl group, and examples thereof include 3-butylthiophene, 3,4-dibutylthiophene, 3-hexylthiophene, 3-octylthiophene, and 3-decylthiophene. Even more preferred are those having 4 or more carbon atoms, such as 2-n-octylthiophene represented by the following formula (4) and 3-n-octylthiophene represented by the formula (5). [ka] [ka]

[0015] The contents of Components A and B constituting the oil leak stopper composition according to the present invention are, based on the total mass of the oil leak stopper composition containing Component C, such that the content of Component A is 0.1 to 30 mass%, preferably 1 to 20 mass%, more preferably 2 to 15 mass%, and particularly preferably 5 to 12 mass%.

[0016] If the content of component A is less than 0.1% by mass, it may be impossible to ensure sufficient swelling. On the other hand, if the content of component A exceeds 30% by mass, it may be difficult to provide swelling in proportion to the increase in the content, and it may be impossible to achieve a balance between the volume change and the hardness change.

[0017] On the other hand, the content of component B is 0.05 to 20 mass %, preferably 0.1 to 15 mass %, more preferably 0.05 to 10 mass %, and particularly preferably 1 to 8 mass %.

[0018] If the content of Component B is less than 0.05% by mass, the volume change imparted to the sealing material is small and sufficient swelling properties may not be imparted, whereas if it exceeds 20% by mass, there is a risk that the hardness change will progress excessively.

[0019] The mixing ratio of component A and component B is preferably in the range of 0.05 to 5 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably 0.3 to 1.5 parts by mass of component B per 1 part by mass of component A.

[0020] If the amount of component B is less than 0.05 parts by mass relative to 1 part by mass of component A, the swelling effect on the sealing material may be almost insufficient, the volume change may be small, and sufficient sealing properties may not be maintained. On the other hand, if the amount exceeds 5 parts by mass, the swelling property commensurate with the increase in the amount of component B may not be obtained, and there is a risk that the balance between the volume change and the hardness change may be impaired. When Component B is mixed in a range of 0.05 to 5 parts by mass relative to 1 part by mass of Component A, a synergistic effect can be achieved in which improvements in volume change and hardness change for the sealing material are well balanced.

[0021] Component C Component C is a base oil that serves as a medium for Components A and B and is used to adjust the viscosity of the lubricating oil composition. In addition to additives that enhance the seal swelling effects of Components A and B, at least one other lubricating oil additive is also blended with the base oil. The additive that enhances the seal swelling effect can be selected arbitrarily, but examples include metal dithiocarbamate salts, specifically ZnDTC. ZnDTC has been shown to be compatible with rubber seals, and its use as a component of the oil leak stopper composition of the present invention contributes to improving swelling properties. The base oil can be selected from the same lubricating base oils described below depending on the application, but various mineral oils, vegetable oils, and synthetic oils can also be used. As the mineral oil, for example, a lubricating oil fraction produced in a petroleum refining process that is typically used as a lubricating base oil can be used. Specifically, solvent-refined mineral oils, hydrocracked mineral oils, hydrorefined mineral oils, wax hydrocracked mineral oils, or mixtures thereof can be used, which are obtained by selecting a refining process such as solvent refining, hydrocracking, hydrorefining, solvent dewaxing, or catalytic dewaxing from lubricating oil feedstock. Examples of vegetable oils include rapeseed oil. Examples of synthetic oils include polyalphaolefins (PAOs), esters of dibasic acids (e.g., phthalic acid, succinic acid, alkylsuccinic acid, alkenylsuccinic acid, oleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, and linoleic acid dimer) with various alcohols (e.g., butyl alcohol, hexyne alcohol, 2-ethylhexyne alcohol, dodecyl alcohol, ethylene glycol, diethylene glycol monoether, and propylene glycol), and esters of monocarboxylic acids having 5 to 18 carbon atoms with polyols (e.g., neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, and tripentaerythritol). These are commercially available. The viscosity of component C depends on the intended use of the lubricating oil additive composition of the present invention and is determined in accordance with the viscosity of the lubricating base oil. However, a kinematic viscosity at 100°C in the range of 4 to 35 mm / s is generally preferred.

[0022] The content of component C is the remainder of the total amount of components A, B, and other additives, and varies depending on the contents of components A and B, but is 50% by mass or more, preferably 65% by mass or more.

[0023] lubricating oil composition The lubricating oil composition of the present invention comprises a lubricating base oil, the oil leak stopper composition blended into the lubricating base oil, and other lubricating oil additives blended as needed.

[0024] Lubricant base oil The lubricating base oil constituting the lubricating oil composition of the present invention is not particularly limited as long as it is usable and can be used as a normal lubricating base oil, but it is preferable to use one that can completely dissolve the oil leak stopper composition used as a component of the lubricating oil composition of the present invention. Specifically, a mineral oil base oil, a GTL (Gas to Liquid) base oil, a synthetic oil base oil, or a mixed oil base oil thereof that meets these requirements can be used.

[0025] As the mineral oil base oil, solvent-refined mineral oil or hydrotreated mineral oil obtained by treating lubricating oil fractions or residual oils obtained as distillates by vacuum distillation of residual oils from atmospheric distillation units of paraffinic, intermediate-base, or naphthenic crude oils using any of a variety of refining processes selected from solvent refining, hydrocracking, hydrotreating, hydrorefining, solvent dewaxing, catalytic dewaxing, and clay treatment, as well as mineral oils obtained by a process combining solvent refining and hydrotreating, or mineral oils obtained by treating deasphalted oil obtained by solvent deasphalting of vacuum distillation residual oil using the above-mentioned refining processes, or mineral oils obtained by isomerization of the wax component, or mixed oils of these can be used as the base oil base.

[0026] The refined base oil base stocks obtained as described above include light neutral oil, medium neutral oil, heavy neutral oil, bright stock, and the like, which have different viscosity levels. Mineral oil base oils can be produced by appropriately blending these base stocks so as to satisfy the required properties, such as kinematic viscosity, depending on the application of the lubricating oil product.

[0027] Examples of GTL oil base oils include lubricating oil fractions separated from liquid products obtained by the GTL process using natural gas as a raw material, and lubricating oil fractions obtained by hydroisomerization or hydrocracking of produced wax. Furthermore, lubricating oil fractions separated from liquid produced oils obtained by the ATL (Asphalt to Liquid) process using heavy residual oil components such as asphalt as a raw material can also be used.

[0028] On the other hand, synthetic base oils include polyalphaolefin oligomers (e.g., poly(1-hexene), poly(1-octene), poly(1-decene), etc., and mixtures thereof); polybutene; ethylene-alkylene copolymers; alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, di(2-ethylhexyl)benzene, dinonylbenzene, etc.); polyphenyls (e.g., biphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers and alkylated diphenyl sulfides and their derivatives; dibasic acids (e.g., phthalic acid, succinic acid, alkylsuccinic acid, alkenylsuccinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, phenylalanine ... Examples of the esters include esters of various alcohols (e.g., butyl alcohol, hexyl alcohol, 2-ethylhexyl alcohol, dodecyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) with monocarboxylic acids having 5 to 18 carbon atoms and polyols (e.g., neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.); and polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers, phosphate esters, etc.

[0029] The lubricating base oil is produced by mixing two or more of the above-mentioned mineral base oils, synthetic base oils, and GTL base oils alone or in combination to satisfy the desired viscosity and other properties depending on the application of the lubricating oil composition.

[0030] As the lubricating base oil, a mixed base oil of a synthetic oil base oil and a mineral oil base oil is particularly suitable, and a mixed base oil of a GTL oil base oil and a mineral oil base oil, a mixed base oil consisting of two or more types of mineral oil base oils, or a mixed base oil consisting of two or more types of GTL oil base oils is preferred, and further, a mixed base oil of a GTL oil base oil and a mineral oil base oil and a mixed base oil consisting of two or more types of mineral oil base oils are suitable from the viewpoint of achieving a balance between viscosity characteristics and economy.

[0031] The viscosity of the lubricating base oil as a constituent component of the lubricating oil composition of the present invention is determined depending on the application of the lubricating oil composition, but in the current situation where low viscosity oils are required from the viewpoint of environmental conservation, the kinematic viscosity of the lubricating base oil at 100°C is controlled to be in the range of 2 to 10 mm / s, preferably 3 to 7 mm / s.

[0032] If the viscosity of the lubricating base oil is too high, the friction resistance will increase and the friction coefficient in the hydrodynamic lubrication region will increase, resulting in problems such as poor fuel economy.On the other hand, if the viscosity is too low, the wear of sliding parts, such as the valve train, piston rings, and bearings of an internal combustion engine, will increase.

[0033] The content of the lubricating base oil is 99.5 to 50 mass %, preferably 99 to 60 mass %, and more preferably 95 to 70 mass %, based on the total mass of the lubricating oil composition.

[0034] The lubricating oil composition of the present invention comprises a lubricating base oil and the oil leak stopper composition blended into the lubricating base oil, and various other additives may be optionally blended to satisfy the performance requirements of the lubricating oil composition depending on its intended use.

[0035] In a lubricating oil composition comprising a lubricating base oil and an oil leak stopper composition containing Components A and B blended with the lubricating base oil, the content of the oil leak stopper composition is in the range of 0.1 to 30 mass% based on the total mass of the lubricating oil composition. It is preferably 0.15 to 20 mass%, more preferably 0.2 to 15 mass%. If the content of the oil leak stopper composition is less than 0.1 mass%, it may not be possible to impart sufficient swelling properties to the rubber seal material, and it may not be possible to prevent lubricating oil seepage. On the other hand, if it exceeds 30 mass%, the properties of the lubricating oil composition obtained by adding the oil leak stopper composition may become unbalanced, resulting in a decrease in lubricity.

[0036] The content of component A in the lubricating oil composition of the present invention is in the range of 0.01 to 6 mass%, preferably 0.05 to 5 mass%, more preferably 0.1 to 4 mass%, and particularly preferably 0.15 to 3 mass%, based on the total mass of the lubricating oil composition.

[0037] The content of component B is in the range of 0.01 to 5 mass %, preferably 0.05 to 4 mass %, more preferably 0.1 to 3 mass %, and particularly preferably 0.15 to 2.5 mass %.

[0038] If the content of component A is less than 0.01% by mass, the effect on swelling will be insufficient, whereas if it exceeds 5% by mass, it may become difficult to maintain a balance between volume change and hardness change. Furthermore, if the content of component B is less than 0.01% by mass, the effect on swelling may be insufficient, while if it exceeds 5% by mass, there is a risk that the balance between volume change and hardness change due to an excess of component B may be impaired.

[0039] Other additives The lubricating oil composition of the present invention is suitable as an automatic transmission oil, continuously variable transmission oil, hydraulic oil, gear oil, turbine oil, compressor oil, engine oil, etc., and the viscosity can be adjusted as needed by selecting the base oil. In order to satisfy the performance requirements for each application, various additives such as viscosity index improvers, ashless dispersants, organic acid metal salts (metal detergents), antioxidants, extreme pressure agents, metal deactivators, pour point depressants, rust inhibitors, colorants, etc. can be added as appropriate.

[0040] Viscosity index improvers generally include non-dispersant polymethacrylates, dispersant polymethacrylates, non-dispersant olefin copolymers (polyisobutylene, ethylene-propylene copolymers), dispersant olefin copolymers, polyalkylstyrenes, styrene-butadiene hydrogenated copolymers, styrene-maleic anhydride ester copolymers, and star-shaped isoprene. Non-dispersant olefin copolymers have dispersant properties without containing oxygen or nitrogen in the molecule. The molecular weight of polyisobutylene or ethylene-propylene copolymers is preferably 100,000 or more in terms of weight average molecular weight (as calculated as polystyrene by GPC analysis). These may be used alone or in combination. They are typically used in a ratio of 0.01% to 30% by mass.

[0041] Ashless dispersants include additives containing succinimide, succinamide, benzylamine, succinic acid ester, succinic acid ester-amide, etc., and boron-containing additives thereof, with succinimide-based and boron-containing succinimide-based being preferred. The blending amount of succinimide-based and boron-containing succinimide-based is usually 0.05% by mass to 8% by mass.

[0042] Examples of metallic detergents include those containing compounds selected from sulfonates, phenates, salicylates, and carboxylates of calcium, magnesium, barium, etc., and those with different base numbers such as overbased salts, basic salts, and neutral salts can be selected and used as desired. The amount of these to be added is preferably usually in the range of 0.05% by mass to 5% by mass in terms of the amount of metal element.

[0043] Examples of friction modifiers include organic molybdenum compounds, as well as fatty acids, higher alcohols, fatty acid esters, oils and fats, amines, polyamides, sulfurized esters, phosphate esters, acidic phosphate esters, phosphites, and phosphate amine salts, which are usually used in a proportion of 0.05% by mass to 5% by mass.

[0044] Antiwear agents generally include zinc dithiophosphate, metal dithiophosphates (Pb, Sb, Mo, etc.), metal dithiocarbamates (Zn, Pb, Sb, Mo, etc.), metal naphthenates (Pb, etc.), metal salts of fatty acids (Pb, etc.), boron compounds, phosphate esters, phosphites, and amine salts of phosphate esters, and are usually used in a proportion of 0.1% by mass to 5% by mass.

[0045] Examples of antioxidants include amine-based antioxidants such as alkylated diphenylamine, phenyl-α-naphthylamine, and alkylated phenyl-α-naphthylamine; phenol-based antioxidants such as 2,6-di-t-butylphenol, 4,4'-methylenebis(2,6-di-t-butylphenol), and isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; sulfur-based antioxidants such as dilauryl-3,3'-thiodipropionate; phosphorus-based antioxidants such as phosphites; molybdenum-based antioxidants; and zinc dithiophosphate. Amine-based antioxidants, phenol-based antioxidants, and combinations thereof are particularly preferred. These are typically used in a proportion of 0.05% to 5% by mass.

[0046] Examples of extreme pressure agents include ashless sulfide compounds, sulfurized oils and fats, phosphate esters, phosphites, and phosphate amine salts, and these are usually used in a proportion of 0.05% to 3% by mass.

[0047] Examples of metal deactivators include benzotriazole, triazole derivatives, benzotriazole derivatives, and thiadiazole derivatives, and these are usually used in a proportion of 0.01% to 3% by mass.

[0048] Examples of pour point depressants include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates, polyalkylstyrenes, etc., and polymethacrylates are particularly preferred. These are usually used in a proportion of 0.01% by mass to 5% by mass.

[0049] Examples of rust inhibitors include fatty acids, alkenyl succinic acid half esters, fatty acid soaps, alkylsulfonic acid groups, polyhydric alcohol fatty acid esters, fatty acid amines, oxidized paraffins, and alkyl polyoxyethylene ethers, and these are usually used in a proportion of 0.01% by mass to 3% by mass.

[0050] Furthermore, when preparing a lubricating oil composition, additive packages such as an engine oil additive package or an automatic transmission fluid (ATF) additive package are used depending on the application, but useful additives can also be selected and used from the above-mentioned additive group. Engine oils typically contain, in addition to friction modifiers, antioxidants, detergents and dispersants, metal deactivators, antiwear agents, viscosity index improvers, rust inhibitors, corrosion inhibitors, etc. Specific examples of the blending amounts of each additive are as follows. Of course, these are merely examples of blending amounts, and the types and blending amounts of additives are not limited to these descriptions. [Table 1] New lubricating oil composition In the present invention, the new lubricating oil composition is a component used in the method of using a conventional oil leak stopper composition, and is a lubricating oil composition obtained by blending the oil leak stopper composition with the above lubricating oil composition. Method of using oil leak stopper composition The oil leak stopper composition of the present invention can be used in at least the following two ways. The first method of use relates to a method of using an oil leak stopper composition, which comprises blending an effective amount of the oil leak stopper composition with a lubricating oil composition comprising a lubricating oil base oil and a lubricating oil additive, and injecting the resulting new lubricating oil composition into the lubrication mechanism system of an automobile or the like. Normally, lubricating oil products are sold in the form of a lubricating base oil blended with an oil leak stopper composition and all necessary additives, and the user then injects this into their engines. However, the present invention provides a method for blending an effective amount of an oil leak stopper into commercially available lubricating oil products that are sold in the market and do not contain an oil leak stopper or that have insufficient rubber swelling properties. The properties of the oil leak stopper, such as density, 40°C kinematic viscosity, 100°C kinematic viscosity, and viscosity index, are adjusted as shown in the examples below so as not to change the specific gravity, kinematic viscosity, pour point, coefficient of friction, or wear resistance of the resulting new lubricating oil composition. From this perspective, the amount of oil leak stopper to be blended is an effective amount, which is 1 to 30 mass %, preferably 2 to 20 mass %, and more preferably 5 to 15 mass %, based on the total mass of the new lubricating oil composition. The second method of use is to supply the oil leak stopper composition to a lubricating oil composition filled in the lubrication mechanism of an automobile or the like through an oil filler port of the lubrication mechanism system. The properties of the oil leak stopper composition are as described in the first method above, and the blending amount can be 1 to 30 mass % as described above. According to the method for using such an oil leak stopper composition, the sealing performance of the seal material can be maintained by imparting seal swelling properties to the lubricating oil composition used in a simple manner. [Example]

[0051] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. The test materials used in the tests for evaluating the swelling properties of rubber sealing materials in the examples and the test methods for evaluating the swelling properties of rubber sealing materials are listed below. Furthermore, "%" in the examples and the like indicates "% by mass" based on the total mass of the composition unless otherwise specified.

[0052] 1. Test Materials (a) Oil leak stopper sample (hereinafter referred to as "LTP") An oil leak stopper sample was prepared by mixing components selected from the following components A, B, and C in the ratios shown in each example. (1) Component A: Trimellitic anhydride polyol ester: Palub 8434H (Patech) (2) Component B: Substituted sulfolane: Lubrizol 730 (manufactured by Lubrizol Corporation) Alkyl-substituted thiophene: 2-n-octylthiophene (Tokyo Chemical Industry Co., Ltd.) (3) Component C: Additive-based oils: Commercially available oil 1: Super Oil N460 (manufactured by ENEOS) Commercially available oil 2: Bylon Forth 5W20C (manufactured by Chugai Yukagaku Kogyo Co., Ltd.) Commercially available oil 3: YUBASE4 (SK Lubricants) Commercially available oil 4: YUBASE6 (SK Lubricants) Viscosity index improver: Commercially available VI improver 1 VISCOPLEX3 (R) -220 (Evonik) Commercially available engine oil additives: HITEC (R) 9858A (Afton) Thickener: Commercially available VI improver (manufactured by Evonik) (b) Rubber seal material sample (1) Fluoroelastomer (FKM) (manufactured by DuPont) (2) Acrylic rubber (ACM) (manufactured by Nippon General Contractor Co., Ltd.) (3) Nitrile butadiene rubber (NBR) (manufactured by JSR Corporation) (c) Test oil In the evaluation test of rubber sealing materials, the following commercially available oils 7 to 9 were used as test oils. (1) Commercial oil 7: Engine oil 0W20 (2) Commercial oil 8: Engine oil 5W30 (3) Commercial oil 9: Engine oil 5W30

[0053] 2. Rubber sealant swelling evaluation test method The swelling of the oil leak stopper sample due to the rubber seal material was evaluated based on the volume change rate and hardness change. The procedure for the evaluation test is as follows: (1) Volume change In accordance with Japanese Industrial Standards (JIS) K 6258, sealing material test pieces measuring 2.5 cm wide, 4 cm long, and 3 mm thick were cut from rubber sealing material and immersed in the prototype oil or commercially available oil in a test container at 120°C for 168 hours, and the rate of change (%) in the volume of the test piece after immersion relative to the volume of the test piece before immersion was determined. The volume change rate (%) was calculated using the following formula. The volume of the test piece before and after immersion was calculated by subtracting the mass of the test piece in distilled water from the mass of the test piece in air. The mass of the test piece was measured to the nearest 1 mg using a precision balance, with a stainless steel wire attached to the end of the test piece so that it could be hung.

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[0054] A mixture of 30 mass% Commercial Oil 1 and 70 mass% Commercial Oil 2 was used as the additive base oil, to which 10 mass% trimellitic anhydride polyol ester as Component A and 5 mass% substituted sulfolane as Component B were added, followed by 10 mass% viscosity index improver, 4 mass% commercial engine oil additive, and 4 mass% friction reducer to prepare developed oil leak stopper LPT1. The composition of developed oil leak stopper LPT1 is shown in Table 2, and its main properties are shown in Table 3. [Manufacturing Example 2]

[0055] An oil leak stopper development product LPT2 was prepared having the same composition as in Production Example 1, except that the amount of substituted sulfolane used as Component B was increased to 10 mass %. [Table 2] [Table 3] [Comparative Manufacturing Example 1] An oil leak stopper comparison product 1 (Comparative LPT1) was prepared using all the same components as the oil leak stopper obtained in Production Example 1, except that the oil leak stopper sample did not contain the substituted sulfolane of Component B. The composition of oil leak stopper comparative product 1 is shown in Table 4. [Comparative Manufacturing Example 2] A comparative oil leak stopper product 2 (comparative LPT2) was prepared having the same composition as that of Production Example 1, except that it did not contain trimellitic anhydride polyol ester as component A. The composition of comparative oil leak stopper product 2 (comparative LPT2) is shown in Table 4. [Table 4] [Example 1]

[0056] The oil leak stopper development product LPT1 prepared in Production Example 1 was blended at 10 mass% with commercially available engine oil 70W20 as test oil 1 to obtain prototype oil 1. Prototype oil 1 was subjected to the rubber sealant swelling evaluation test described above, using nitrile butadiene rubber (NBR), fluoroelastomer (FKM), and acrylic rubber (ACM) as rubber sealants. The measurement results are shown in Tables 5 to 7. [Example 2] The oil leak stopper development product LPT1 prepared in Production Example 1 was blended at 10 mass% with commercially available engine oil No. 8 85W30 to obtain prototype oil 2. Prototype oil 2 was subjected to the rubber sealant swelling evaluation test described above, using nitrile butadiene rubber (NBR), fluoroelastomer (FKM), and acrylic rubber (ACM) as rubber sealants. The measurement results are shown in Tables 5 to 7. [Example 3] The oil leak stopper development product LPT1 prepared in Production Example 1 was blended at 10 mass% with commercially available 95W30 oil to obtain prototype oil 3. Prototype oil 3 was subjected to the rubber sealant swelling evaluation test using fluoroelastomer (FKM), acrylic rubber (ACM), and nitrile butadiene rubber (NBR) as rubber sealants. The measurement results are shown in Tables 5 to 7. [Example 4] The prototype oil 4 (commercial oil 7 + LPT2) was obtained by blending 10% by mass of the oil leak stopper development product 2 (LPT2) prepared in Production Example 2 with commercial oil 7. The prototype oil 4 was subjected to the rubber seal swelling evaluation test using nitrile butadiene rubber (NBR) as the rubber seal. The measurement results are shown in Table 5. [Example 5] Test oil 2 was prepared by blending 10 mass% of the oil leak stopper development product 2 (LPT2) prepared in Production Example 2 with commercial oil 8 to obtain prototype oil 5 (commercial oil 8 + LPT2). This was subjected to a rubber sealant swelling evaluation test in the same manner as in Example 4. The measurement results are shown in Table 5. [Example 6] The prototype oil 6 (Commercial Oil 9 + LPT2) was obtained by blending 10 mass% of the oil leak stopper development product 2 (LPT2) described in Example 4 with the commercial oil 9 (test oil 3), and was subjected to a rubber seal swelling evaluation test. The measurement results are shown in Table 5. [Comparative Example 1]

[0057] Comparative oil leak stopper 1 (Comparative LPT1) prepared in Comparative Production Example 1 was blended in a concentration of 10 mass% with commercially available engine oil 7 to obtain Comparative prototype oil 1. Using Comparative prototype oil 1 as a rubber sealant, nitrile butadiene rubber (NBR) was subjected to the rubber sealant swelling evaluation test. The measurement results are shown in Tables 5 to 7. Comparative Example 2 Comparative oil sample 2 was prepared by blending 10 mass % of comparative oil leak stopper sample 1 (comparative LPT1) prepared in Comparative Production Example 1 into commercially available engine oil 8, and the obtained comparative oil sample 2 was subjected to a rubber sealant swelling evaluation test in the same manner as in Comparative Example 1. The measurement results are shown in Table 5. Comparative Example 3 Comparative oil leak stopper 1 (Comparative LPT1) prepared in Comparative Production Example 1 was blended in 10 mass % with commercially available engine oil 9 to obtain Comparative prototype oil 3, which was subjected to a rubber seal swelling evaluation test in the same manner as Comparative Example 1. The measurement results are shown in Table 5. [Comparative Examples 4 to 6] Comparative oil leak stopper product 2 (Comparative LPT2) prepared in Comparative Production Example 2 was blended in 10 mass% each into commercial engine oils 7, 8, and 9 to produce comparative prototype oils 4, 5, and 6, which were subjected to a rubber sealant swelling evaluation test in the same manner as in Comparative Example 1. The measurement results are shown in Table 5. [Table 5] [Table 6] [Table 7]

[0058] The following points became clear from the results of the above-mentioned Examples and Comparative Examples. 1. As mentioned above, a predetermined amount of the developed oil leak stopper according to the present invention was added to three types of commercially available engine oil (containing no oil leak stopper or corresponding seal swelling agent) to obtain test oils. As a result, it was clear that in all test oils, the volume change and hardness change of all rubber seal materials were significantly improved. For example, in the swelling evaluation test using nitrile butadiene rubber (NBR) in Table 5, the volume change rate for commercially available engine oil 7 was -6.0% and the hardness change was 6.2, while the prototype oil 1 containing 10% by mass of the oil leak stopper development product 1 according to the present invention showed an improvement of -2% in volume change rate and 4.2 in hardness change. 2. It has been confirmed that the components A and B of the oil leak prevention agent developed according to the present invention have little effect on swelling when used alone, but when used in combination they produce a significantly more pronounced synergistic effect. For example, in a nitrile butadiene rubber (NBR) swelling evaluation test, as shown in Table 5, the volume change rate of commercial engine oil 7 was -6.0%, while the effect of comparative LPT1 containing only component A was -4.8%. The effect of containing only component B, sulfolane, was only an increase of -4.0%. However, when both components were used in combination, a significant synergistic improvement of -2.0% was observed, as shown in Example 1.

Claims

1. 1. An oil leak stopper composition for use as a component of a lubricating oil composition, comprising: An oil leak stopper composition comprising at least component A and component B, Component A contains a polyol ester of trimellitic anhydride, The component B contains a sulfolane having a substituent. An oil leak stopper composition characterized by:

2. An oil leak stopper composition comprising component A, component B, and component C, 2. The oil leak stopper composition according to claim 1, wherein said component C is a base oil which is a medium for said components A and B and at least one other lubricating oil additive.

3. 2. The oil leak stopper composition according to claim 1, wherein the content of Component A is 0.1 to 30 mass % and the content of Component B is 0.05 to 20 mass %, based on the total mass of the oil leak stopper composition containing Component A and Component B.

4. 2. The oil leak stopper composition according to claim 1, wherein the mixing ratio of component A to component B is in the range of 0.05 to 5 parts by mass of component B relative to 1 part by mass of component A.

5. A lubricating oil composition comprising a lubricating base oil, the oil leak stopper composition according to any one of claims 1 to 4 blended into the lubricating base oil, and at least one other lubricating oil additive composition selected arbitrarily.

6. 6. The lubricating oil composition according to claim 5, wherein the content of the oil leak stopper composition in the lubricating oil composition is 1 to 30 mass % based on the total mass of the lubricating oil composition.

7. The lubricating oil composition according to claim 5, wherein the lubricating oil composition is used as a lubricating oil for internal combustion engines, lubricating oil for hybrid automobiles, lubricating oil for electric automobiles, lubricating oil for fuel cell-equipped automobiles, lubricating oil for vehicles equipped with hydrogen engines, and lubricating oil for automatic transmissions and continuously variable transmissions of the above vehicles, as well as other drive system lubricating oils.

8. A method for using an oil leak stopper, comprising adding an effective amount of the oil leak stopper composition according to any one of claims 1 to 4 to a lubricating oil composition filled in a lubrication mechanism system through an oil supply part of the lubrication mechanism system, thereby maintaining the sealing performance of a seal material in the lubrication mechanism system.

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