Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
  • C10M169/04—Mixtures of base-materials and additives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/02—Hydroxy compounds
  • C10M2207/023—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings
  • C10M2207/026—Hydroxy compounds having hydroxy groups bound to carbon atoms of six-membered aromatic rings with tertiary alkyl groups
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
  • C10M2207/40—Fatty vegetable or animal oils
  • C10M2207/401—Fatty vegetable or animal oils used as base material
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant Compositions
  • C10M2215/02—Amines, e.g. polyalkylene polyamines; Quaternary amines
  • C10M2215/06—Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to carbon atoms of six-membered aromatic rings
  • C10M2215/064—Di- and triaryl amines
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant Compositions
  • C10M2215/02—Amines, e.g. polyalkylene polyamines; Quaternary amines
  • C10M2215/06—Amines, e.g. polyalkylene polyamines; Quaternary amines having amino groups bound to carbon atoms of six-membered aromatic rings
  • C10M2215/064—Di- and triaryl amines
  • C10M2215/065—Phenyl-Naphthyl amines
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2219/00—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions
  • C10M2219/04—Organic non-macromolecular compounds containing sulfur, selenium or tellurium as ingredients in lubricant compositions containing sulfur-to-oxygen bonds, i.e. sulfones, sulfoxides
  • C10M2219/044—Sulfonic acids, Derivatives thereof, e.g. neutral salts
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
  • C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
  • C10M2223/04—Phosphate esters
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M2223/00—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions
  • C10M2223/02—Organic non-macromolecular compounds containing phosphorus as ingredients in lubricant compositions having no phosphorus-to-carbon bonds
  • C10M2223/04—Phosphate esters
  • C10M2223/045—Metal containing thio derivatives
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/02—Pour-point; Viscosity index
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/04—Detergent property or dispersant property
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
  • C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
  • C10N2030/10—Inhibition of oxidation, e.g. anti-oxidants

Definitions

• the present invention relates to a lubricating oil composition, and a method of using the composition and a method of producing the composition.
• Patent Literature 1 as an animal and vegetable lubricating oil having a low-melting point property, a high viscosity, and high stability, there is a proposal of the following animal and vegetable lubricating oil: the content of an isolated trans-isomer in constituent fatty acids of a triglyceride is 40 mass% or more, and the oil has an iodine value of from 50 to 90.
• Patent Literature 1 only an investigation on a base oil has been made, and an investigation on a lubricating oil composition including additive formulation has not been made.
• An object of the present invention is to provide a lubricating oil composition using a vegetable oil as a base oil, the composition being excellent in oxidation stability, and a method of using the composition and a method of producing the composition.
• the lubricating oil composition using a vegetable oil as a base oil the composition being excellent in oxidation stability, and the method of using the composition and the method of producing the composition can be provided.
• a lubricating oil composition of this embodiment includes: a vegetable oil (A); a zinc dithiophosphate (B); and an amine-based antioxidant (C).
• the total content of linoleic acid and linolenic acid among constituent fatty acids of the vegetable oil (A) is less than 20 mass% with respect to the total amount of the constituent fatty acids in the vegetable oil (A).
• the content of the amine-based antioxidant (C) is 2.00 mass% or more with respect to the total amount of the lubricating oil composition.
• the lubricating oil composition further includes a phosphorus-free phenol-based antioxidant (D)
• the content of the phosphorus-free phenol-based antioxidant (D) is less than 2.00 mass% with respect to the total amount of the lubricating oil composition.
• the inventor of the present invention has made extensive investigations with a view to solving the above-mentioned problem. As a result, the inventor has found that the following items (I) to (IV) are important in the preparation of a lubricating oil composition excellent in oxidation stability through use of a vegetable oil as a base oil:
• the "vegetable oil (A),” the “zinc dithiophosphate (B),” the “amine-based antioxidant (C),” and the “phosphorus-free phenol-based antioxidant (D)” are also referred to as “component (A),” “component (B),” “component (C),” and “component (D),” respectively.
• the lubricating oil composition of this embodiment may be formed only of the “component (A),” the “component (B),” and the “component (C),” the composition may or may not include the “component (D),” and one or more kinds selected from other components except the “component (A),” the “component (B),” the “component (C),” and the “component (D)” to the extent that the incorporation of such component does not deviate from the gist of the present invention.
• the total content of the "component (A)," the “component (B),” and the “component (C)” is preferably 35 mass% or more, more preferably 40 mass% or more, still more preferably 50 mass% or more, still further more preferably 60 mass% or more, yet still further more preferably 70 mass% or more, even more preferably 80 mass% or more, still even more preferably 90 mass% or more, yet still even more preferably 95 mass% or more with respect to the total amount of the lubricating oil composition.
• the lubricating oil composition of this embodiment includes the vegetable oil (A) as a base oil.
• the total content of linoleic acid and linolenic acid among the constituent fatty acids of the vegetable oil (A) is less than 20 mass% with respect to the total amount of the constituent fatty acids in the vegetable oil (A) (hereinafter also referred to as "requirement 1").
• the lubricating oil composition When the total content of linoleic acid and linolenic acid is 20 mass% or more, the lubricating oil composition is liable to undergo oxidative degradation, and hence the oxidation stability of the lubricating oil composition is liable to be insufficient.
• consumer fatty acids of the vegetable oil (A) means fatty acids in a compound for forming the vegetable oil in which the fatty acids and glycerin are ester-bonded to each other.
• the total content of linoleic acid and linolenic acid is preferably 18 mass% or less, more preferably 16 mass% or less, still more preferably 15 mass% or less with respect to the total amount of the constituent fatty acids in the vegetable oil (A).
• the content of oleic acid among the constituent fatty acids of the vegetable oil (A) is preferably 65 mass% or more with respect to the total amount of the constituent fatty acids in the vegetable oil (A) (hereinafter also referred to as "requirement 2").
• the content of oleic acid is more preferably 70 mass% or more, still more preferably 75 mass% or more with respect to the total amount of the constituent fatty acids in the vegetable oil (A).
• the content of oleic acid is typically less than 85 mass% with respect to the total amount of the constituent fatty acids in the vegetable oil (A).
• the content of a saturated fatty acid among the constituent fatty acids of the vegetable oil (A) is preferably 3 mass% or more with respect to the total amount of the constituent fatty acids in the vegetable oil (A) (hereinafter also referred to as "requirement 3").
• the content is more preferably 4 mass% or more, still more preferably 5 mass% or more.
• saturated fatty acid that may be incorporated into the constituent fatty acids of the vegetable oil (A) include one or more kinds selected from the group consisting of: lauric acid; myristic acid; palmitic acid; stearic acid; arachidic acid; behenic acid; and lignoceric acid.
• a particularly typical example thereof is palmitic acid.
• a method of measuring the fatty acid composition of the vegetable oil (A) is, for example, a method including: extracting a lipid from the vegetable oil (A) with an organic solvent; evaporating the organic solvent after the extraction; then preparing a fatty acid methyl ester from the resultant lipid; and subjecting the fatty acid methyl ester to gas chromatography mass spectrometry (GC-MS analysis).
• GC-MS analysis gas chromatography mass spectrometry
• Examples of the vegetable oil (A) to be used in this embodiment include: a raw oil obtained by squeezing and extracting a natural vegetable oil raw material; a refined oil obtained by subjecting the raw oil to various kinds of refining treatment, such as filtration for removing a floating impurity in the raw oil, degumming for removing a phospholipid or the like, deacidification for removing a free fatty acid, decolorization for removing coloring matter, and dewaxing for removing a wax content; and a modified oil and fat obtained by subjecting the refined oil to treatment, such as hardening, fractionation, ester exchange, or hydrogenation.
• refining treatment such as filtration for removing a floating impurity in the raw oil, degumming for removing a phospholipid or the like, deacidification for removing a free fatty acid, decolorization for removing coloring matter, and dewaxing for removing a wax content
• a modified oil and fat obtained by subjecting the refined oil to treatment
• the vegetable oil (A) include: vegetable oils, such as olive oil, sunflower oil (preferably high-oleic type), Carthamus Tinctorius oil (preferably high-oleic type), safflower oil (preferably high-oleic type), palm oil, palm kernel oil, and coconut oil; and plant-derived base oils such as an estolide ester.
• vegetable oils such as olive oil, sunflower oil (preferably high-oleic type), Carthamus Tinctorius oil (preferably high-oleic type), safflower oil (preferably high-oleic type), palm oil, palm kernel oil, and coconut oil
• plant-derived base oils such as an estolide ester.
• the vegetable oil (A) may be formed only of one kind of vegetable oil, or may be a mixed vegetable oil including two or more kinds of vegetable oils.
• the mixed vegetable oil only needs to satisfy the above-mentioned requirement 1, and the mixed vegetable oil preferably further satisfies at least one of the above-mentioned requirement 2 or 3, and more preferably satisfies all of the above-mentioned requirements 1, 2, and 3.
• the content of the vegetable oil (A) is preferably 30 mass% or more, more preferably 40 mass% or more, still more preferably 50 mass% or more, still further more preferably 60 mass% or more, yet still further more preferably 70 mass% or more, even more preferably 80 mass% or more, still even more preferably 85 mass% or more, yet still even more preferably 90 mass% or more with respect to the total amount of the lubricating oil composition.
• the content of the vegetable oil (A) is preferably 97.9 mass% or less with respect to the total amount of the lubricating oil composition.
• the lubricating oil composition of this embodiment includes the zinc dithiophosphate (B).
• the lubricating oil composition of this embodiment is free of the zinc dithiophosphate (B), the lubricating oil composition is liable to undergo oxidative degradation, and hence the oxidation stability of the lubricating oil composition is liable to be insufficient.
• the zinc dithiophosphate (B) is preferably, for example, a compound represented by the following general formula (b-1): wherein in the general formula (b-1), R h1 to R b4 each independently represent a monovalent hydrocarbon group.
• the hydrocarbon group is not particularly limited as long as the group is a monovalent hydrocarbon group, and from the viewpoint of improving the oxidation stability, preferred examples thereof include an alkyl group, an alkenyl group, a cycloalkyl group, and an aryl group. Among them, an alkyl group is preferred.
• the zinc dithiophosphate (B) to be used in this embodiment is preferably a zinc dialkyldithiophosphate.
• the cycloalkyl group and the aryl group that may each be selected as each of R b1 to R b4 may be, for example, polycyclic groups, such as a decalyl group and a naphthyl group.
• the monovalent hydrocarbon group that may be selected as each of R b1 to R b4 may be a group having a substituent containing an oxygen atom and/or a nitrogen atom, such as a hydroxy group, a carboxy group, an amino group, an amide group, a nitro group, or a cyano group, or may be partially substituted with a nitrogen atom, an oxygen atom, a halogen atom, or the like.
• the monovalent hydrocarbon group is a cycloalkyl group or an aryl group, the group may further have a substituent, such as an alkyl group or an alkenyl group.
• each of the groups is preferably a primary or secondary group. Among them, a primary alkyl group or a secondary alkyl group is preferred, and a primary alkyl group is more preferred.
• the zinc dialkyldithiophosphate to be used in this embodiment is preferably a zinc dialkyldithiophosphate having a primary alkyl group or a secondary alkyl group, or a combination thereof, more preferably a primary zinc dialkyldithiophosphate or a secondary zinc dialkyldithiophosphate, or a combination thereof, still more preferably a primary zinc dialkyldithiophosphate.
• the number of the carbon atoms of the hydrocarbon group represented by any one of R b1 to R b4 is preferably 1 or more, more preferably 2 or more, still more preferably 3 or more, and the upper limit thereof is preferably 24 or less, more preferably 18 or less, still more preferably 12 or less, still further more preferably 10 or less.
• the monovalent hydrocarbon group is an alkenyl group
• the number of the carbon atoms thereof is preferably 2 or more, more preferably 3 or more
• the upper limit thereof is preferably 24 or less, more preferably 18 or less, still more preferably 12 or less, still further more preferably 10 or less.
• the monovalent hydrocarbon group is a cycloalkyl group
• the number of the carbon atoms thereof is preferably 5 or more, and the upper limit thereof is preferably 20 or less.
• the monovalent hydrocarbon group is an aryl group
• the number of the carbon atoms thereof is preferably 6 or more, and the upper limit thereof is preferably 20 or less.
• the content of the zinc dithiophosphate (B) is preferably 0.10 mass% or more, more preferably 0.20 mass% or more, still more preferably 0.30 mass% or more, still further more preferably 0.40 mass% or more, yet still further more preferably 0.50 mass% or more with respect to the total amount of the lubricating oil composition.
• the content is preferably 1.00 mass% or less, more preferably 0.90 mass% or less, still more preferably 0.80 mass% or less.
• the zinc dithiophosphates (B) may be used alone or in combination thereof.
• the lubricating oil composition of this embodiment includes the amine-based antioxidant (C).
• the content of the amine-based antioxidant (C) needs to be 2.00 mass% or more with respect to the total amount of the lubricating oil composition.
• the lubricating oil composition When the content of the amine-based antioxidant (C) is less than 2.00 mass% with respect to the total amount of the lubricating oil composition, the lubricating oil composition is liable to undergo oxidative degradation, and hence the oxidation stability of the lubricating oil composition is liable to be insufficient.
• the content of the amine-based antioxidant (C) is preferably 3.00 mass% or more, more preferably 3.50 mass% or more, still more preferably 3.80 mass% or more with respect to the total amount of the lubricating oil composition.
• the content of the amine-based antioxidant (C) is preferably 8.00 mass% or less, more preferably 7.00 mass% or less, still more preferably 6.00 mass% or less with respect to the total amount of the lubricating oil composition.
• An amine-based antioxidant generally used as an antioxidant for a lubricating oil composition may be used as the amine-based antioxidant (C).
• the amine-based antioxidant (C) preferably contains a diphenylamine-based antioxidant (C1) and a naphthylamine-based antioxidant (C2).
• the total content of the diphenylamine-based antioxidant (C1) and the naphthylamine-based antioxidant (C2) is preferably from 50 mass% to 100 mass%, more preferably from 60 mass% to 100 mass%, still more preferably from 70 mass% to 100 mass%, still further more preferably from 80 mass% to 100 mass%, yet still further more preferably from 90 mass% to 100 mass%, even more preferably from 95 mass% to 100 mass% with respect to the total amount of the amine-based antioxidant (C).
• the diphenylamine-based antioxidant (C1) and the naphthylamine-based antioxidant (C2) are described in detail below.
• the "diphenylamine-based antioxidant (C1)” and the “naphthylamine-based antioxidant (C2)” are also referred to as “component (C1)” and “component (C2),” respectively.
• a diphenylamine-based antioxidant generally used as an antioxidant for a lubricating oil composition may be used as the diphenylamine-based antioxidant (C1).
• the diphenylamine-based antioxidants (C1) may be used alone or in combination thereof.
• the diphenylamine-based antioxidant (C1) is preferably a compound represented by the following general formula (c1-1): wherein in the general formula (c1-1), R c11 and R c12 each independently represent an alkyl group having 1 to 30 carbon atoms.
• the number of the carbon atoms of the alkyl group is from 1 to 30, an improvement in oxidation stability of the lubricating oil composition can be further facilitated.
• the numbers of the carbon atoms of the alkyl groups that may be selected as R c11 and R c12 are each independently preferably from 1 to 20, more preferably from 4 to 16, still more preferably from 4 to 14.
• alkyl group that may be selected as each of R c11 and R c12 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group, a docosyl group, a tricosyl group, a tetracosyl group, a pentacosyl group, a hexacosyl group, a
• nc11 and nc12 each independently represent an integer of from 1 to 5.
• nc11 and nc12 each independently represent preferably from 1 to 3, more preferably 1 or 2, still more preferably 1.
• the compounds each represented by the general formula (c1-1) may be used alone or in combination thereof.
• a naphthylamine-based antioxidant generally used as an antioxidant for a lubricating oil composition may be used as the naphthylamine-based antioxidant (C2).
• the naphthylamine-based antioxidants (C2) may be used alone or in combination thereof.
• the numbers of the carbon atoms of the alkyl group that may be selected as R c21 are each independently preferably from 1 to 20, more preferably from 4 to 16, still more preferably from 4 to 14.
• alkyl group that may be selected as R c21 include those given as the examples of the alkyl group that may be selected as each of R c11 and R c12 .
• the alkyl group may be linear or branched.
• nc21s each independently represent an integer of from 1 to 5.
• nc21s each independently represent preferably from 1 to 3, more preferably 1 or 2, still more preferably 1.
• the compounds each represented by the general formula (c2-1) may be used alone or in combination thereof.
• a content ratio [(C1)/(C2)] between the diphenylamine-based antioxidant (C1) and the naphthylamine-based antioxidant (C2) is preferably from 0.10 to 9.00, more preferably from 0.25 to 4.00, still more preferably from 0.50 to 2.00, still further more preferably from 0.75 to 1.25 in terms of mass ratio from the viewpoint of further facilitating improvements in effects of the present invention.
• a content ratio [(B)/(C)] between the zinc dithiophosphate (B) and the amine-based antioxidant (C) is preferably from 0.01 to 0.50, more preferably from 0.05 to 0.30, still more preferably from 0.10 to 0.20 in terms of mass ratio from the viewpoint of further facilitating improvements in effects of the present invention.
• the lubricating oil composition of this embodiment may further include the phosphorus-free phenol-based antioxidant (D).
• the content of the phosphorus-free phenol-based antioxidant (D) needs to be less than 2.00 mass% with respect to the total amount of the lubricating oil composition.
• the content of the phosphorus-free phenol-based antioxidant (D) is preferably as small as possible.
• the phosphorus-free phenol-based antioxidant (D) is, for example, a phosphorus-free phenol-based antioxidant having a phenol skeleton to be generally used as an antioxidant for a lubricating oil composition.
• the phosphorus-free phenol-based antioxidant (D) encompasses not only a compound, which has a phenol skeleton and is formed only of a carbon atom, a hydrogen atom, and an oxygen atom, but also a compound (sulfur-containing phenol compound), which has a phenol skeleton and has a sulfur atom in addition to a carbon atom, a hydrogen atom, and an oxygen atom.
• the content of a compound represented by the following general formula (d-1), the compound serving as the phosphorus-free phenol-based antioxidant (D), is particularly preferably as small as possible: wherein in the general formula (d-1), R d1 represents an alkylene group having 1 to 5 carbon atoms.
• the number of the carbon atoms of the alkylene group that may be selected as R d1 may be from 1 to 4, may be from 1 to 3, or may be 1 or 2.
• linear alkylene groups such as a methylene group, an ethylene group, a n-propylene group, a n-butylene group, and a n-pentylene group
• branched alkylene groups such as an isopropylene group, an isobutylene group, a sec-butylene group, a tert-butylene group, an isopentylene group, and a neopentylene group.
• R d2 represents an alkyl group having 1 to 25 carbon atoms.
• the number of the carbon atoms of the alkyl group that may be selected as R d2 may be from 2 to 20, may be from 4 to 15, or may be from 6 to 10.
• alkyl group that may be selected as R d2 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a henicosyl group, a docosyl group, a tricosyl group, a tetracosyl group, and a pentacosyl group.
• Those groups may be linear or branched.
• R d3 and R d4 each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms.
• Examples of the alkyl group that may be selected as each of R d3 and R d4 include the same examples as those of the alkyl group that may be selected as each of R c1 and R c2 described above.
• the numbers of the carbon atoms of the alkyl groups that may be selected as R d3 and R d4 may each independently be from 1 to 20, may each independently be from 1 to 10, or may each independently be from 1 to 6.
• the phosphorus-free phenol-based antioxidant (D) may have a hindered phenol skeleton.
• the alkyl group that may be selected as each of R d3 and R d4 may be a branched alkyl group, may be a branched alkyl group having 1 to 6 carbon atoms, or may be a tert-butyl group.
• the lubricating oil composition of this embodiment preferably further includes a zinc dithiocarbamate (E).
• E zinc dithiocarbamate
• the oxidation stability of the lubricating oil composition can be further improved.
• the zinc dithiocarbamate (E) is preferably, for example, a compound represented by the following general formula (e-1): wherein in the general formula (e-1), R e1 to R e4 each independently represent a monovalent hydrocarbon group.
• R e1 to R e4 each independently represent a monovalent hydrocarbon group.
• the same groups as those of R b1 to R b4 in the general formula (b-1) may each be used as the monovalent hydrocarbon group.
• an alkyl group that may be selected as each of R e1 to R e4 is preferably a primary alkyl group or a secondary alkyl group, or a combination thereof, more preferably a primary alkyl group.
• the number of the carbon atoms of the alkyl group that may be selected as each of R e1 to R e4 is preferably from 3 to 12, more preferably from 3 to 10, still more preferably from 3 to 8.
• a primary zinc dithiocarbamate or a secondary zinc dithiocarbamate, or a combination thereof is more preferred, and a primary zinc dithiocarbamate is more preferred.
• the content of the zinc dithiocarbamate (E) is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, still more preferably 0.08 mass% or more with respect to the total amount of the lubricating oil composition.
• the content of the zinc dithiocarbamate (E) is preferably 1.00 mass% or less, more preferably 0.50 mass% or less, still more preferably 0.30 mass% or less with respect to the total amount of the lubricating oil composition.
• the zinc dithiocarbamates (E) may be used alone or in combination thereof.
• the lubricating oil composition of this embodiment preferably further includes a phosphorus-containing phenol-based antioxidant (F).
• a phosphorus-containing phenol-based antioxidant (F) can interact with the amine-based antioxidant (C) to further improve anti-oxidation performance exhibited by the amine-based antioxidant (C).
• the phosphorus-containing phenol-based antioxidant (F) is preferably, for example, a compound represented by the following general formula (f-1): wherein in the general formula (f-1), R f1 , R f2 , R f3 , and R f4 each independently represent a hydrogen atom or an alkyl group having 1 to 30 carbon atoms.
• Examples of the alkyl group that may be selected as each of R f1 , R f2 , R f3 , and R f4 include the same examples as those of the alkyl group that may be selected as each of R c1 and R c2 described above.
• the numbers of the carbon atoms of the alkyl groups that may be selected as R f1 , R f2 , R f3 , and R f4 are each independently preferably from 1 to 20, more preferably from 1 to 10, still more preferably from 1 to 6.
• the phosphorus-containing phenol-based antioxidant (F) preferably has a hindered phenol skeleton.
• the alkyl group that may be selected as each of R f1 and R f2 is preferably a branched alkyl group, more preferably a branched alkyl group having 1 to 6 carbon atoms, still more preferably a tert-butyl group.
• R f5 represents an alkylene group having 1 to 5 carbon atoms.
• the number of the carbon atoms of the alkylene group that may be selected as R f5 is preferably from 1 to 4, more preferably from 1 to 3, still more preferably 1 or 2, still further more preferably 1.
• a methylene group is preferred.
• the content of the phosphorus-containing phenol-based antioxidant (F) is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, still more preferably 0.08 mass% or more with respect to the total amount of the lubricating oil composition.
• the content of the phosphorus-containing phenol-based antioxidant (F) is preferably 1.00 mass% or less, more preferably 0.50 mass% or less, still more preferably 0.30 mass% or less with respect to the total amount of the lubricating oil composition.
• the lubricating oil composition of this embodiment may include any other component except the components (A) to (F) to the extent that the effects of the present invention are not impaired.
• Examples of the other component include a metal deactivator, a rust inhibitor, and an antifoaming agent. Those components may be used alone or in combination thereof.
• a detergent dispersant may be further incorporated as the other component.
• one or more kinds selected from a mineral oil and a synthetic oil may be further incorporated as the other component.
• the metal deactivator examples include a benzotriazole-based compound, a tolyltriazole-based compound, a thiadiazole-based compound, an imidazole-based compound, and a pyrimidine-based compound.
• the content of the metal deactivator is preferably from 0.01 mass% to 5.0 mass%, more preferably from 0.15 mass% to 3.0 mass% with respect to the total amount of the lubricating oil composition.
• the metal deactivators may be used alone or in combination thereof.
• Examples of the rust inhibitor include a sulfonic acid metal salt, an organic phosphorous acid ester, an organic phosphoric acid ester, an organic phosphoric acid metal salt, an alkenylsuccinic acid ester, and an alkenylsuccinic acid polyhydric alcohol ester.
• the sulfonic acid metal salt is a metal salt of any of various sulfonic acids.
• the various sulfonic acids for forming the sulfonic acid metal salt include an aromatic petroleum sulfonic acid, an alkyl sulfonic acid, an aryl sulfonic acid, and an alkylaryl sulfonic acid.
• preferred examples thereof include dodecylbenzenesulfonic acid, dilaurylcetylbenzenesulfonic acid, benzenesulfonic acid substituted with paraffin wax, benzenesulfonic acid substituted with polyolefin, benzenesulfonic acid substituted with polyisobutylene, naphthalenesulfonic acid, and dinonylnaphthalenesulfonic acid. Among them, dinonylnaphthalenesulfonic acid is more preferred.
• a metal for forming the sulfonic acid metal salt is preferably, for example, sodium, magnesium, calcium, zinc, or barium.
• sodium, magnesium, calcium, zinc, or barium is preferred, and barium is more preferred from the viewpoints of a rust-inhibiting property, storage stability, and ease of availability.
• the content of the rust inhibitor is preferably from 0.01 mass% to 10.0 mass%, more preferably from 0.030 mass% to 5.00 mass% with respect to the total amount of the lubricating oil composition.
• the rust inhibitors may be used alone or in combination thereof.
• antifoaming agent examples include: silicone-based antifoaming agents; fluorine-based antifoaming agents, such as a fluorosilicone oil and a fluoroalkyl ether; and polyacrylate-based antifoaming agents.
• the content (active ingredient amount) of the antifoaming agent is preferably from 0.001 mass% to 0.50 mass%, more preferably from 0.01 mass% to 0.30 mass% with respect to the total amount of the lubricating oil composition.
• the antifoaming agents may be used alone or in combination thereof.
• detergent dispersant examples include a metal sulfonate, a metal salicylate, a metal phenate, and succinimide.
• the content of the detergent dispersant is typically from 0.01 mass% to 10 mass%, preferably from 0.1 mass% to 5 mass% with respect to the total amount of the lubricating oil composition.
• Examples of the synthetic oil include: polyolefins, such as polybutene, a 1-octene oligomer, and a 1-decene oligomer, and hydrogenated products thereof, and an ethylene- ⁇ -olefin copolymer; isoparaffin; various esters, such as a polyol ester and a dibasic acid ester; various ethers such as polyphenyl ether; polyalkylene glycols; alkylbenzenes; alkylnaphthalenes; and GTL base oils obtained by isomerizing waxes (gas-to-liquid (GTL) waxes) produced from natural gas by a Fischer-Tropsch process.
• polyolefins such as polybutene, a 1-octene oligomer, and a 1-decene oligomer, and hydrogenated products thereof, and an ethylene- ⁇ -olefin copolymer
• isoparaffin such as a polyol ester and
• the mineral oils may be used alone or in combination thereof.
• the synthetic oils may also be used alone or in combination thereof.
• one or more kinds of the mineral oils and one or more kinds of the synthetic oils may be used in combination.
• the lubricating oil composition of this embodiment includes one or more kinds selected from the mineral oil and the synthetic oil, from the viewpoint of the gist of the present invention into which the concept of carbon neutrality is introduced, its content is preferably 100 parts by mass or less, more preferably 50 parts by mass or less, still more preferably 10 parts by mass or less with respect to 100 parts by mass of the vegetable oil (A).
• the 40°C kinematic viscosity of the lubricating oil composition of this embodiment is preferably from 19.8 mm 2 /s to 352 mm 2 /s, more preferably from 28.8 mm 2 /s to 242 mm 2 /s, still more preferably from 28.8 mm 2 /s to 165 mm 2 /s.
• the acid value of the lubricating oil composition of this embodiment after an ISOT test described in Examples to be described later is preferably 20.0 mgKOH/g or less, more preferably 15.0 mgKOH/g or less, still more preferably 10.0 mgKOH/g or less.
• the millipore value of the lubricating oil composition of this embodiment after an ISOT test described in Examples to be described later is preferably 20 mg/100 mL or less, more preferably 10 mg/100 mL or less, still more preferably 5 mg/100 mL or less.
• the carbon amount of the lubricating oil composition of this embodiment after a panel coking test described in Examples to be described later is preferably 60 mg or less, more preferably 50 mg or less, still more preferably 40 mg or less.
• the zinc amount of the lubricating oil composition is preferably from 0.01 mass% to 0.15 mass%, more preferably from 0.02 mass% to 0.12 mass%, still more preferably from 0.03 mass% to 0.10 mass% with respect to the total amount of the lubricating oil composition.
• the zinc amount in the lubricating oil composition may be measured in conformity with, for example, JPI-5S-38-03.
• the molybdenum amount of the lubricating oil composition of this embodiment is preferably less than 0.01 mass%, more preferably less than 0.001 mass% with respect to the total amount of the lubricating oil composition. It is still more preferred that the composition be free of molybdenum.
• the molybdenum amount in the lubricating oil composition may be measured in conformity with, for example, JPI-5S-38-03.
• the content of the viscosity index improver in the lubricating oil composition of this embodiment is preferably less than 0.01 mass%, more preferably less than 0.001 mass% with respect to the total amount of the lubricating oil composition. It is still more preferred that the composition be free of the viscosity index improver.
• a method of producing a lubricating oil composition of this embodiment is not particularly limited.
• the method of producing a lubricating oil composition of this embodiment includes a step of mixing a vegetable oil (A), a zinc dithiophosphate (B), and an amine-based antioxidant (C) to prepare the lubricating oil composition.
• the total content of linoleic acid and linolenic acid among constituent fatty acids of the vegetable oil (A) is less than 20 mass% with respect to the total amount of the constituent fatty acids in the vegetable oil (A).
• the blending amount of the amine-based antioxidant (C) is 2.00 mass% or more with respect to the total amount of the lubricating oil composition.
• the blending amount of the phosphorus-free phenol-based antioxidant (D) is less than 2.00 mass% with respect to the total amount of the lubricating oil composition.
• the production method may further include a step of blending one or more kinds selected from a zinc dithiocarbamate (E) and a phosphorus-containing phenol-based antioxidant (F) as required.
• E zinc dithiocarbamate
• F phosphorus-containing phenol-based antioxidant
• the production method may further include a step of blending the above-mentioned other component as required.
• a method of mixing the respective components is not particularly limited, for example, a method including blending the respective components into the vegetable oil (A) is available.
• each of the components may be blended after a diluting oil or the like has been added to bring the component into a solution (dispersion) form.
• the respective components are preferably dispersed in a uniform manner through stirring by a known method.
• the blending amounts and blending ratios of the component (A), the component (B), the component (C), the component (D), the component (E), and the component (F) are preferably set to blending amounts and blending ratios corresponding to preferred contents and preferred content ratios of the component (A), the component (B), the component (C), the component (D), the component (E), and the component (F) described above.
• the lubricating oil composition according to this embodiment is excellent in oxidation stability. Accordingly, the lubricating oil composition of this embodiment hardly causes various problems such as the occurrence of sludge resulting from its oxidative degradation, and hence the lubricating oil composition can be stably used over a long time period.
• the lubricating oil composition of this embodiment is used as, for example, a lubricating oil composition for machinery and equipment in which excellent oxidation stability is required.
• the composition is preferably used as an industrial equipment oil.
• the industrial equipment oil is, for example, a hydraulic oil, a turbine oil, a compressor oil, a machine tool oil, or a gear oil.
• the lubricating oil composition according to this embodiment may be suitably used as a rotary air compressor oil or a reciprocating air compressor oil among them, and may be particularly suitably used as a reciprocating air compressor oil.
• the lubricating oil composition according to this embodiment provides the following usage methods (1) to (4):
• a 40°C kinematic viscosity and a viscosity index were measured and calculated in conformity with JIS K2283:2000.
• the term "Other component" in constituent fatty acids of the vegetable oil (A) and the vegetable oil (A') refers to any other fatty acid to be incorporated except linoleic acid, linolenic acid, oleic acid, and palmitic acid among the constituent fatty acids of the vegetable oils.
• the zinc dialkyldithiophosphate is a compound containing a primary zinc dialkyldithiophosphate as a main component.
• the alkyl groups for forming the zinc dialkyldithiophosphate include a primary alkyl group having 6 carbon atoms (a hexyl group) as a main component, and partially include an isobutyl group and an isopropyl group.
• the content of zinc in the zinc dialkyldithiophosphate is 8.5 mass%.
• a benzenepropanoic acid 3,5-bis(1,1-dimethylethyl)-4-hydroxy-alkyl ester is a compound represented by the general formula (d-1) in which R d1 represents an alkylene group having 2 carbon atoms, R d2 represents an alkyl group having 8 carbon atoms, and R d3 and R d4 represent tert-butyl groups.
• Zinc diamyldithiocarbamate was used as the zinc dithiocarbamate (E).
• Zinc diamyldithiocarbamate is a compound represented by the general formula (e-1) in which R e1 to R e4 each represent an amyl group (a pentyl group, that is, a primary alkyl group having 5 carbon atoms).
• the content of zinc in zinc diamyldithiocarbamate is 6.2 mass%.
• Diethyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphonate is a compound represented by the general formula (f-1) in which R f1 and R f2 represent tert-butyl groups, R f3 and R f4 represent ethyl groups, and R f5 represents a methylene group.
• test oil lubricating oil composition
• ISOT test in conformity with JIS K 2514-1:2013 was performed to forcibly degrade the test oil.
• a test temperature oil temperature
• the increase rate of the 40°C kinematic viscosity represented in the unit of percentage was obtained by calculating the percentage by which the 40°C kinematic viscosity of the lubricating oil composition after the ISOT test (post-test oil) increased as compared to that of the lubricating oil composition before the ISOT test (new oil). It can be said that as the increase rate of the 40°C kinematic viscosity becomes lower, the lubricating oil composition becomes more excellent in oxidation stability.
• the acid value of the lubricating oil composition after the ISOT test was measured in conformity with the indicator method of JIS K2501:2003.
• the millipore value of the lubricating oil composition after the ISOT test was measured in conformity with ASTM D7873 by using a membrane filter manufactured by Millipore Corporation, the filter having an average pore diameter of 1.0 ⁇ m.
• a test was performed in conformity with Fed. Test Method Std. 791-3462 under the conditions of a panel temperature of 270°C and an oil temperature of 80°C in a cycle formed of a splash time of 15 seconds and a stop time of 45 seconds for 3 hours. After the completion of the test, the amount of carbon adhering to a panel (carbon adhesion amount (mg)) was evaluated.
• the content of zinc in each of the lubricating oil compositions of Examples 1 and 3 is 0.0657 mass% (with respect to the total amount of the lubricating oil composition, calculated value), and the content of zinc in the lubricating oil composition of Example 2 is 0.0595 mass% (with respect to the total amount of the lubricating oil composition, calculated value).
• the lubricating oil compositions of Examples 1 to 3 are each a lubricating oil composition excellent in oxidation stability because the compositions are each low in kinematic viscosity increase rate, acid value, and millipore value after the ISOT test (120°C ⁇ 240 hours), and in carbon adhesion amount after the panel coking test (270°C).
• the lubricating oil compositions of Comparative Examples 1 to 5 are each a lubricating oil composition poor in oxidation stability because at least one of the kinematic viscosity increase rate, acid value, or millipore value of each of the compositions after the ISOT test (120°C ⁇ 240 hours), or the carbon adhesion amount thereof after the panel coking test (270°C) is high or unmeasurable.

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