Anti-wear agent and lubricating oil composition

Abstract

The purpose of the present invention is to provide an anti-wear agent having a high anti-wear effect and a lubricating oil composition containing the anti-wear agent. The present invention relates to an anti-wear agent which contains a copolymer (A) that contains, as essential constituent monomers, a monomer (a) represented by general formula (1) and a monomer (b) represented by general formula (2), and which is characterized in that the weight ratio (b / a) of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005-0.12. [In general formula (1), A1 represents a polymerizable group; -X < 1->,-X < 2-> and-X < 3-> are each independently a group represented by-O-or-NH-; r1 represents an alkylene group having 1 to 4 carbon atoms; r2 is an alkylene group having 2 to 20 carbon atoms; r3 represents a hydrogen atom, a linear or branched alkyl group having 1-44 carbon atoms, a phenyl group having a linear or branched alkyl group having 1-44 carbon atoms, an acyl group having a linear or branched alkyl group having 1-44 carbon atoms, or a benzoyl group having a linear or branched alkyl group having 1-44 carbon atoms; and p is an integer of 1-100, and when p is 2 or more, the plurality of R2 and X3 may be the same or different. ] [In general formula (2), R4 is a hydrogen atom or a methyl group; -X4 <-> is a group represented by-O <-> or-NH <->; r5 represents an alkylene group having 1 to 4 carbon atoms; and-X < 5-> is a group represented by-O-or-NH-. ]. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to an antiwear agent and a lubricating oil composition. Background Art

[0002] In recent years, in order to improve fuel consumption performance, it has been required to improve the power transmission efficiency and reduce the size and weight of automotive transmissions. The transmission mechanism has also changed from a manual transmission to an automatic transmission, and recently, continuously variable transmissions have been installed in some vehicles. On the other hand, electric vehicles equipped with lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, fuel cells, etc. and equipped with electric motors, or hybrid vehicles that combine these batteries with internal combustion engines have been developed, and transmission oil and motor oil are used in these vehicles, respectively.

[0003] Recently, in electric vehicles or hybrid vehicles, generalization of these oils and reduction of size and weight by encapsulating the transmission and the motor have been required, and a new type of oil is desired that has insulation properties and copper compatibility as a motor oil in addition to antiwear properties as a manual transmission oil, an automatic transmission oil, or a continuously variable transmission oil.

[0004] In order to meet requirements such as antiwear properties and seizure prevention properties, friction modifiers are used, and usually phosphate esters, zinc dialkyldithiophosphates, organic sulfur compounds, etc. are added to mineral oil-based or synthetic base oils. However, the transmission oil containing these friction modifiers has a corrosive effect on copper, and in addition, the insulation properties are not sufficient. Therefore, when used as motor oil, there are problems such as copper wire breakage and motor short circuit. Therefore, in electric vehicles or hybrid vehicles, a friction modifier that can balance copper compatibility, insulation properties, and antiwear properties is required.

[0005] As friction modifiers that do not deteriorate copper compatibility and insulation properties, polymer-type friction modifiers that do not contain sulfur or phosphorus in their constituent elements can be cited. Specifically, copolymers composed of α-olefins and fumaric acid esters (Patent Document 1), acrylate copolymers having hydroxyl groups (Patent Document 2), polyesters having hydrophilic polymer units and polyolefin units (Patent Document 3), methacrylate copolymers having a block structure composed of polar segment units and hydrophobic segment units (Patent Document 4), etc. are known. However, the above polymer friction modifiers have a problem of insufficient friction reduction effect.

[0006] As a friction modifier for solving the above problems, (meth)acrylate copolymers having a monomer with a specific structure as an essential constituent monomer are known (Patent Documents 5 and 6). However, although the above friction modifiers have a high friction reduction effect, their antiwear effect is not yet clear.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent No. 3730660 Gazette

[0010] Patent Document 2: Japanese Patent No. 5822706 Gazette

[0011] Patent Document 3: Japanese Patent No. 5684832 Gazette

[0012] Patent Document 4: Japanese Unexamined Patent Application Publication No. 4686444 Gazette

[0013] Patent Document 5: Japanese Unexamined Patent Application Publication No. 2022 - 151618 Gazette

[0014] Patent Document 6: Japanese Patent No. 6582021 Gazette Summary of the Invention

[0015] Problems to be Solved by the Invention

[0016] An object of the present invention is to provide an anti - wear agent having a high anti - wear effect and a lubricating oil composition containing the anti - wear agent.

[0017] Means for Solving the Problems

[0018] The present inventors conducted in - depth research and as a result, completed the present invention.

[0019] That is, the present invention relates to an anti - wear agent which is a copolymer (A) containing a monomer (a) represented by the following general formula (1) and a monomer (b) represented by the following general formula (2) as essential constituent monomers, wherein the weight ratio (b / a) of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005 to 0.12; and a lubricating oil composition containing the anti - wear agent and a base oil.

[0020] [Chemical Formula 1]

[0021]

[0022] [In General Formula (1), A 1 is a polymerizable group; - X 1 -, - X 2 - and - X 3 - are each independently a group represented by - O - or - NH -; R 1 is an alkylene group having 1 to 4 carbon atoms; R 2 is an alkylene group having 2 to 20 carbon atoms; R 3is a hydrogen atom, a linear or branched alkyl group having 1 to 44 carbon atoms, a phenyl group having a linear or branched alkyl group with 1 to 44 carbon atoms, an acyl group having a linear or branched alkyl group with 1 to 44 carbon atoms, or a benzoyl group having a linear or branched alkyl group with 1 to 44 carbon atoms; p is an integer from 1 to 100, and when p is 2 or more, multiple Rs 2 and X 3 may each be the same or different.]

[0023] [Chemical formula 2]

[0024]

[0025] [In general formula (2), R 4 is a hydrogen atom or a methyl group; -X 4 - is a group represented by -O- or -NH-; R 5 is an alkylene group having 1 to 4 carbon atoms; -X 5 - is a group represented by -O- or -NH-.]

[0026] Effects of the Invention

[0027] The antiwear agent of the present invention and the lubricating oil composition containing the antiwear agent of the present invention exhibit excellent antiwear effects. Detailed Embodiments

[0028] <Antiwear Agent>

[0029] The antiwear agent of the present invention is an antiwear agent of a copolymer (A) containing a monomer (a) represented by the following general formula (1) and a monomer (b) represented by the following general formula (2) as essential constituent monomers, wherein the weight ratio (b / a) of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005 to 0.12.

[0030] [Chemical formula 3]

[0031]

[0032] [In general formula (1), A 1 is a polymerizable group; -X 1 -, -X 2 - and -X 3 - are each independently a group represented by -O- or -NH-; R 1 is an alkylene group having 1 to 4 carbon atoms; R 2 is an alkylene group having 2 to 20 carbon atoms; R 3is a hydrogen atom, a linear or branched alkyl group having 1 to 44 carbon atoms, a phenyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, an acyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, or a benzoyl group having a linear or branched alkyl group having 1 to 44 carbon atoms; p is an integer of 1 to 100, and when p is 2 or more, a plurality of R 2 and X 3 may be the same or different from each other.]

[0033] [Chemical Formula 4]

[0034]

[0035] [In General Formula (2), R 4 is a hydrogen atom or a methyl group; -X 4 - is a group represented by -O- or -NH-; R 5 is an alkylene group having 1 to 4 carbon atoms; -X 5 - is a group represented by -O- or -NH-.]

[0036] The anti-wear effect in the present invention is a physical property for evaluating to what extent a lubricating oil composition can withstand a load without seizure under high load conditions where wear is likely to occur, such as 700 N or more.

[0037] On the other hand, the friction reduction effect is a physical property for evaluating how much kinetic energy loss can be reduced under low load conditions where wear is unlikely to occur, such as 30 N.

[0038] As described above, the anti-wear effect and the friction reduction effect are different physical properties.

[0039] <Copolymer (A)>

[0040] In the present invention, the copolymer (A) is a copolymer having the monomer (a) represented by the above general formula (1) and the monomer (b) represented by the above general formula (2) as essential constituent monomers, and the weight ratio (b / a) of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005 to 0.12.

[0041] In the present invention, the copolymer (A) contains the monomer (a) represented by the above general formula (1) as an essential constituent monomer.

[0042] A in General Formula (1) 1 is a monovalent polymerizable group. A polymerizable group refers to a functional group capable of undergoing a polymerization reaction. Specifically, a radical polymerizable group or a cationic polymerizable group can be cited. As the polymerizable group, for example, a vinyl group, a (meth)acryloyl group, etc. can be cited.

[0043] From the aspect of anti-wear property, A 1Preferably vinyl and (meth)acryloyl groups, more preferably (meth)acryloyl groups.

[0044] It should be noted that in the present invention, "(meth)acryloyl group" means "acryloyl group and / or methacryloyl group", and "(meth)acrylate" means "acrylate and / or methacrylate".

[0045] -X in general formula (1) 1 -, -X 2 - and -X 3 - are each independently a group represented by -O- or -NH-.

[0046] As -X 1 -, -X 2 - and -X 3 -, from the aspect of anti-wear property, is preferably -O-.

[0047] R in general formula (1) 1 is an alkylene group having 1 to 4 carbon atoms.

[0048] As the alkylene group having 1 to 4 carbon atoms, methylene, ethylene, 1,2-propylene or 1,3-propylene, 1,2-butylene, 1,3-butylene or 1,4-butylene, etc. can be cited. Among them, from the aspect of anti-wear property, ethylene and 1,2-propylene or 1,3-propylene are preferred, and ethylene is more preferred.

[0049] p in general formula (1) represents the number of moles of addition of the lactam and / or lactone described later, and is an integer of 1 to 100. From the aspects of anti-wear property and solubility in base oil, it is preferably an integer of 1 to 70, more preferably an integer of 1 to 40, particularly preferably an integer of 1 to 20, and most preferably an integer of 1 to 10.

[0050] When p is 2 or more, multiple R 2 and X 3 can be the same or different from each other.

[0051] In monomer (a) among the monomers constituting copolymer (A), the range of the average value of p per 1 mole of monomer (a) (average number of moles of addition, hereinafter also referred to as the molar average value of p) is preferably 1 to 100, more preferably 1 to 70, further preferably 1 to 40, particularly preferably 1 to 20, and most preferably 1 to 10.

[0052] When there are two or more kinds of monomer (a) constituting copolymer (A), the value obtained by weighted averaging p of each monomer (a) based on the molar fraction of each monomer in monomer (a) is the molar average value of p in general formula (1).

[0053] The mole fraction of each monomer with a different number of p in monomer (a) can be calculated by analyzing the chemical formula and content of each monomer (a) constituting copolymer (A) using methods such as pyrolysis GC / MS.

[0054] Alternatively, when measuring p of monomer (a) before it is introduced into copolymer (A), the molar average value of p can be determined based on the 1 1H-NMR (nuclear magnetic resonance) spectrometry spectrum of monomer (a). As an example, when the "lactam and / or lactone" is ε-caprolactone, the molar average value of p can be calculated by dividing half of the integral value of the peak around 1.4 ppm (the peak of the γ-hydrogen from the carbonyl carbon of ε-caprolactone) by the integral value of the peak around 6.4 ppm or 6.1 ppm (one of the peaks of the hydrogen atoms bonded to the unsaturated double bond of acryloyl or methacryloyl).

[0055] The γ-hydrogen from the carbonyl carbon of ε-caprolactone refers to the hydrogen atom bonded to the carbon atom with * in the structural formula (-CO-CH2-CH2-C * H2-CH2-CH2-O-) of ε-caprolactone.

[0056] The hydrogen atom bonded to the unsaturated double bond of acryloyl refers to the hydrogen atom bonded to the carbon atom with * in the structural formula H2C * =CH-CO-. The hydrogen atom bonded to the unsaturated double bond of methacryloyl refers to the hydrogen atom bonded to the carbon atom with * in the structural formula H2C * =C(CH3)-CO-.

[0057] Specifically, the molar average value of p can be calculated by the following formula.

[0058] (When A in general formula (1) 1 is acryloyl)

[0059] Molar average value of p = (Integral value of the peak of the γ-hydrogen from the carbonyl carbon of ε-caprolactone / 2) / (Integral value of one of the peaks of the hydrogen atoms bonded to the unsaturated double bond of acryloyl)

[0060] (When A in general formula (1) 1 is methacryloyl)

[0061] Molar average value of p = (Integral value of the peak of the γ-hydrogen from the carbonyl carbon of ε-caprolactone / 2) / (Integral value of one of the peaks of the hydrogen atoms bonded to the unsaturated double bond of methacryloyl)

[0062] R in general formula (1) 2represents an alkylene group having 2 to 20 carbon atoms. Specifically, examples of the alkylene group having 2 to 20 carbon atoms include ethylene, isopropylidene, 1,2-propylene or 1,3-propylene, isobutylidene, 1,2-butylene, 1,3-butylene or 1,4-butylene, isopentylidene, 1,2-pentylene, 1,3-pentylene, 1,4-pentylene or 1,5-pentylene, isohexylidene, 1,2-hexylene, 1,3-hexylene, 1,4-hexylene, 1,5-hexylene or 1,6-hexylene, isoheptylidene, 1,2-heptylene, 1,3-heptylene, 1,4-heptylene, 1,5-heptylene, 1,6-heptylene or 1,7-heptylene, isooctylidene, 1,8-octylene, isononylidene, 1,9-nonylene, isodecylidene, 1,10-decylene, isoundecylidene, 1,11-undecylene, isododecylidene, 1,12-dodecylene, isotridecylidene, 1,13-tridecylene, isotetradecylidene, 1,14-tetradecylene, isopentadecylidene, 1,15-pentadecylene, isohexadecylidene, 1,16-hexadecylene, isoheptadecylidene, 1,17-heptadecylene, isooctadecylidene, 1,18-isooctadecylene, isononadecylidene, 1,19-isononadecylene, isoeicosylidene, 1,20-eicosylene, etc.

[0063] As R 2 , from the aspect of antiwear property, it is preferably an alkylene group having 2 to 17 carbon atoms, more preferably an alkylene group having 2 to 15 carbon atoms, particularly preferably an alkylene group having 2 to 13 carbon atoms, and most preferably an alkylene group having 2 to 10 carbon atoms.

[0064] R in the general formula (1) 3 is a hydrogen atom, a linear or branched alkyl group having 1 to 44 carbon atoms, a phenyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, an acyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, or a benzoyl group having a linear or branched alkyl group having 1 to 44 carbon atoms.

[0065] As a linear or branched alkyl group having 1 to 44 carbon atoms, specifically, methyl, ethyl, propyl, butyl, hexyl, n-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, isodecyl, n-undecyl, isoundecyl, n-dodecyl, isododecyl, n-tridecyl, isotridecyl, n-tetradecyl, 2-ethyldodecyl, n-pentadecyl, 2-methyltetradecyl, n-hexadecyl, isohexadecyl, n-heptadecyl, isoheptadecyl, 2-ethylpentadecyl, 2-octylnonyl, 2-(3-methylhexyl)-7-methylnonyl, n-octadecyl, isooctadecyl, 2-hexylundecyl, 2-ethylheptadecyl, 1-hexyltridecyl, n-eicosyl, 2-octylundecyl, isoeicosyl, 1-undecyldodecyl, 1-octylpentadecyl, 2-decyltridecyl, n-tetracosyl, 2-decyltetradecyl, 2-dodecylpentadecyl, 2-heptylicosyl, 2-dodecylhexadecyl, n-triacontyl, 2-tetradecyloctadecyl, n-hexatriacontyl, n-tetracontyl, 2-ethyltetracontyl, and residues obtained by removing hydroxyl groups from oxo alcohols obtained from olefins [such as propylene oligomers (2 to 14 mers), ethylene / propylene oligomers (2 to 20 mers), and isobutene oligomers (2 to 10 mers), etc.], etc.

[0066] As a phenyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, for example, a group in which a part or all of the hydrogen atoms of the phenyl group are substituted with a linear or branched alkyl group having 1 to 44 carbon atoms (such as tolyl, etc.) can be mentioned. As the linear or branched alkyl group having 1 to 44 carbon atoms of the phenyl group, the above examples can be mentioned.

[0067] As an acyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, including an acyl group derived from a carboxylic acid having 2 to 45 carbon atoms having an alkyl group having 1 to 44 carbon atoms, for example, acetyl, propionyl, butyryl, valeryl, hexanoyl, heptanoyl, octanoyl, nonanoyl, decanoyl, lauroyl, myristoyl, palmitoyl, etc. can be mentioned.

[0068] As a benzoyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, for example, a group in which a part or all of the hydrogen atoms of the benzoyl group are substituted with a linear or branched alkyl group having 1 to 44 carbon atoms can be mentioned. As the linear or branched alkyl group having 1 to 44 carbon atoms of the benzoyl group, the above examples can be mentioned.

[0069] These Rs 3Among them, from the aspect of antiwear property, it is preferably a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, an acyl group having 2 to 13 carbon atoms (an acyl group having a linear or branched alkyl group having 1 to 12 carbon atoms), a phenyl group having a linear or branched alkyl group having 1 to 12 carbon atoms, or a benzoyl group having a linear or branched alkyl group having 1 to 12 carbon atoms. More preferably, it is a hydrogen atom, a linear alkyl group having 1 to 12 carbon atoms, an acyl group having a linear alkyl group having 1 to 12 carbon atoms, a phenyl group having a linear alkyl group having 1 to 12 carbon atoms, or a benzoyl group having a linear alkyl group having 1 to 12 carbon atoms. Particularly preferably, it is a hydrogen atom.

[0070] As the monomer (a), from the aspect of antiwear property, preferably, there can be cited a 1 to 100 molar addition product (a1) of a lactone of a hydroxyalkyl (meth) acryloyl monomer, a 1 to 100 molar addition product (a2) of a lactam of a hydroxyalkyl (meth) acryloyl monomer, a 1 to 100 molar addition product (a3) of a lactone of an aminoalkyl (meth) acryloyl monomer, and a 1 to 100 molar addition product (a4) of a lactam of an aminoalkyl (meth) acryloyl monomer, an esterification product (a5) of (a1) or (a3) with a monocarboxylic acid (for example, a monocarboxylic acid having 2 to 45 carbon atoms, etc.), an amidation product (a6) of (a2) or (a4) with a monocarboxylic acid (for example, a monocarboxylic acid having 2 to 45 carbon atoms, etc.), an etherification product (a7) which is a reaction product of (a1) or (a3) with an alkylating agent having 1 to 44 carbon atoms, etc. More preferably, it is a 1 to 100 molar addition product (a1) of a lactone of a hydroxyalkyl (meth) acryloyl monomer.

[0071] The addition molar number of the lactone or lactam in the above examples refers to the average addition molar number.

[0072] As the hydroxyalkyl (meth) acryloyl monomer, for example, there can be cited (meth) acrylic acid hydroxyalkyl esters {(meth) acrylic acid hydroxymethyl ester, (meth) acrylic acid hydroxyethyl ester, (meth) acrylic acid hydroxypropyl ester, (meth) acrylic acid hydroxybutyl ester, etc.}, hydroxyalkyl (meth) acrylamides {hydroxymethyl (meth) acrylamide, hydroxyethyl (meth) acrylamide, hydroxypropyl (meth) acrylamide, hydroxybutyl (meth) acrylamide, etc.}.

[0073] As the aminoalkyl (meth) acryloyl monomer, for example, there can be cited (meth) acrylic acid aminoalkyl esters {(meth) acrylic acid aminomethyl ester, (meth) acrylic acid aminoethyl ester, (meth) acrylic acid aminopropyl ester, (meth) acrylic acid aminobutyl ester, etc.}, aminoalkyl (meth) acrylamides {aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, aminopropyl (meth) acrylamide, aminobutyl (meth) acrylamide, etc.}.

[0074] As lactones, lactones having 3 to 21 carbon atoms can be mentioned, for example, β-propiolactone, γ-butyrolactone, δ-valerolactone, ε-caprolactone, etc.

[0075] As lactams, lactams having 3 to 21 carbon atoms can be mentioned, for example, β-lactam, γ-lactam, δ-lactam, etc.

[0076] As monocarboxylic acids, monocarboxylic acids having 2 to 45 carbon atoms can be mentioned {for example, saturated aliphatic monocarboxylic acids (such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, etc.), unsaturated aliphatic monocarboxylic acids (such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, docosahexaenoic acid, etc.), etc.}, aromatic monocarboxylic acids (such as benzoic acid, compounds in which a part of the hydrogen atoms bonded to the aromatic ring of benzoic acid is substituted with an alkyl group having 1 to 44 carbon atoms, etc.).

[0077] As alkylating agents having 1 to 44 carbon atoms, for example, alkyl chlorides such as methyl chloride, ethyl chloride, propyl chloride, butyl chloride, isopropyl chloride, allyl chloride, etc.; alkyl bromides such as methyl bromide, ethyl bromide, propyl bromide, butyl bromide, isopropyl bromide, etc.

[0078] As the monomer (a), from the aspect of abrasion resistance, a 1 to 10 molar adduct of a lactone with a (meth)acrylic acid hydroxyalkyl ester having 1 to 4 carbon atoms in the hydroxyalkyl group is preferred, a 1 to 10 molar adduct of a lactone with a (meth)acrylic acid hydroxyalkyl ester having 2 to 4 carbon atoms in the hydroxyalkyl group is more preferred, a 1 to 10 molar adduct of ε-caprolactone with a (meth)acrylic acid hydroxyalkyl ester having 2 to 3 carbon atoms in the hydroxyalkyl group is even more preferred, and a 1 to 10 molar adduct of ε-caprolactone with (meth)acrylic acid hydroxyethyl ester is particularly preferred.

[0079] A 1 to 100 molar adduct of a lactone with a hydroxyalkyl (meth)acryloyl monomer or an aminoalkyl (meth)acryloyl monomer can be obtained, for example, by subjecting the hydroxyalkyl (meth)acryloyl monomer or the aminoalkyl (meth)acryloyl monomer to ring-opening addition of a lactone, etc.

[0080] From the aspect of reaction time, the reaction temperature during the ring-opening addition reaction is preferably 80 to 150 °C, more preferably 100 °C to 140 °C.

[0081] The reaction time is preferably 2 to 24 hours, more preferably 3 to 10 hours.

[0082] The reaction can be carried out in the presence of a catalyst.

[0083] As the catalyst for the above reaction, known catalysts can be mentioned, such as p-toluenesulfonic acid, tetrapropyl titanate, stannous octanoate, etc.

[0084] The amount of the catalyst is preferably 0.01 to 5% by mass, more preferably 0.03 to 0.5% by mass, relative to the amount of the reaction product.

[0085] After the ring-opening addition reaction is completed, the catalyst is preferably treated by a method of adsorbing / filtering using an adsorbent, a method of neutralizing to deactivate the catalyst, or the like.

[0086] A 1 to 100 molar adduct of a hydroxyalkyl (meth) acryloyl monomer or an aminoalkyl (meth) acryloyl monomer with a lactam can be obtained, for example, by ring-opening addition of a lactam to a hydroxyalkyl (meth) acryloyl monomer or an aminoalkyl (meth) acryloyl monomer.

[0087] From the aspect of reaction time, the reaction temperature for the ring-opening addition reaction of the lactam is preferably 80 to 150 °C, more preferably 100 to 140 °C.

[0088] The reaction time is preferably 2 to 24 hours, more preferably 3 to 10 hours.

[0089] The reaction can be carried out in the presence of a catalyst.

[0090] As the catalyst for the above reaction, known catalysts can be used, such as tetrapropyl titanate and stannous octanoate.

[0091] The amount of the catalyst is preferably 0.01 to 5% by weight, more preferably 0.03 to 0.5% by weight, relative to the amount of the reaction product.

[0092] After the ring-opening addition reaction is completed, the catalyst is preferably treated by a method of adsorbing / filtering using an adsorbent, a method of neutralizing to deactivate the catalyst, or the like.

[0093] From the aspects of reaction time and prevention of polymerization of (meth) acrylic acid, the reaction temperature for the esterification reaction of a 1 to 100 molar adduct (a1) of a lactone of a hydroxyalkyl (meth) acryloyl monomer or a 1 to 100 molar adduct (a3) of a lactone of an aminoalkyl (meth) acryloyl monomer with a monocarboxylic acid (for example, a monocarboxylic acid having 2 to 45 carbon atoms, etc.) is preferably 80 to 150 °C, more preferably 90 to 130 °C.

[0094] In the esterification reaction, the reaction pressure can be set to a reduced pressure for the purpose of removing the generated water. From the aspects of reaction time and prevention of polymerization, the preferred reaction pressure is preferably 0.007 to 0.095 MPa, more preferably 0.01 to 0.092 MPa.

[0095] The reaction time is preferably 2 to 24 hours, more preferably 3 to 10 hours. The esterification reaction is preferably carried out in the presence of a catalyst.

[0096] As the catalyst for the above esterification reaction, a known catalyst can be used, and examples thereof include sulfuric acid and p-toluenesulfonic acid. In addition, a solvent can also be used in the esterification reaction. As the solvent, a water-insoluble solvent having a boiling point of 150°C or lower, such as cyclohexane and toluene, can be cited.

[0097] From the viewpoints of reaction time and prevention of polymerization of (meth)acrylic acid, when the lactam 1 to 100 molar adduct (a2) of a hydroxyalkyl (meth)acryloyl monomer or the lactam 1 to 100 molar adduct (a4) of an aminoalkyl (meth)acryloyl monomer is subjected to an amidation reaction with a monocarboxylic acid (for example, a monocarboxylic acid having 2 to 45 carbon atoms), the reaction temperature is preferably 80°C to 150°C, more preferably 90°C to 130°C.

[0098] In addition, the amidation reaction can be carried out under reduced pressure for the purpose of removing the generated water. From the viewpoints of reaction time and prevention of polymerization, the preferred reaction pressure is preferably 0.007 to 0.095 MPa, more preferably 0.01 to 0.092 MPa.

[0099] The reaction time is preferably 2 to 24 hours, more preferably 3 to 10 hours.

[0100] The reaction of the lactone 1 to 100 molar adduct (a1) of a hydroxyalkyl (meth)acryloyl monomer or the lactone 1 to 100 molar adduct (a3) of an aminoalkyl (meth)acryloyl monomer with an alkylating agent having 1 to 44 carbon atoms can be obtained by reacting under normal conditions in the presence of a base (such as an amine, a quaternary ammonium salt, sodium hydroxide, etc.).

[0101] From the viewpoint of solubility in a lubricating base oil, the structural unit derived from monomer (a) (the structure in which the polymerizable group (such as vinyl) of monomer (a) reacts to form a single bond) preferably has a specific solubility parameter (hereinafter sometimes abbreviated as SP value).

[0102] The SP value of the structural unit derived from monomer (a) is preferably 9.0 to 12.5 (cal / cm 3 ) 1 / 2 , more preferably 9.3 to 12.3 (cal / cm 3 ) 1 / 2 , particularly preferably 9.5 to 12.0 (cal / cm 3 ) 1 / 2 .

[0103] It should be noted that the SP value in the present invention refers to the value calculated by the mathematical formula (28) on page 153 using the values (heat of vaporization and molar volume of atoms or functional groups at 25 °C) recorded on page 152 (Table 5) of Fedors' method (Polymer Engineering and Science, February, 1974, Vol. 14, No. 2, P147-154). Specifically, it can be calculated by substituting the values of Δe i and v i recorded in Table 1 below, which are parameters of Fedors' method, and using the values corresponding to the types of atoms and atomic groups in the molecular structure into the following mathematical formula.

[0104] SP value = (ΣΔe i / Σv i ) 1 / 2

[0105] [Table 1]

[0106] Parameters of Fedors' method

[0107]

[0108] It should be noted that when two or more kinds of monomers (a) are used as monomers in the copolymer (A), regarding the SP value of the monomer (a), preferably, the SP values of each of the multiple monomers (a) constituting the copolymer (A) are calculated by the above method, and the value obtained by arithmetically averaging the SP values of each monomer (a) based on the weight fraction is within the above range.

[0109] From the aspect of anti-wear property, the molecular formula weight or number average molecular weight (hereinafter simply referred to as Mn) of the monomer (a) is preferably 150-20,000, more preferably 150-10,000, particularly preferably 150-7,000, and most preferably 150-4,000.

[0110] It should be noted that the molecular formula weight or Mn of the monomer (a), the Mn of the monomer (c), and the weight average molecular weight (hereinafter simply referred to as Mw) of the copolymer (A) described later can be measured by gel permeation chromatography (hereinafter simply referred to as GPC) under the following conditions.

[0111] <Measurement conditions for Mn of monomer (a), Mn of monomer (c), and Mw of copolymer (A)>

[0112] Apparatus: "HLC-8320GPC" [manufactured by Tosoh Corporation]

[0113] Column: 1 piece of "TSKgel guardcolumn SuperHZ-L" [manufactured by Tosoh Corporation], 3 pieces of "TSKgel SuperHZM-M" [manufactured by Tosoh Corporation]

[0114] Measurement temperature: 40 °C

[0115] Sample solution: 0.25 wt% tetrahydrofuran solution

[0116] Solution injection volume: 10 μl

[0117] Detection device: RI (differential refractometer)

[0118] Reference substance: 11 kinds of standard polystyrene (TSKstandard POLYSTYRENE) (molecular weights: 589, 1,013, 2,630, 9,100, 19,500, 37,900, 96,400, 190,000, 427,000, 1,090,000, 2,110,000) [manufactured by Tosoh Corporation]

[0119] In the present invention, the copolymer (A) contains the monomer (b) represented by the above general formula (2) as an essential constituent monomer.

[0120] In the general formula (2), R 4 represents a hydrogen atom or a methyl group, and from the viewpoints of antiwear and viscosity index improvement effects, a methyl group is preferred.

[0121] In the general formula (2), -X 4 - is a group represented by -O- or -NH-, and from the viewpoint of antiwear, a group represented by -O- is preferred.

[0122] In the general formula (2), R 5 is an alkylene group having 1 to 4 carbon atoms.

[0123] Examples of the alkylene group having 1 to 4 carbon atoms include a methylene group, an ethylene group, a 1,2-propylene group or a 1,3-propylene group, a 1,2-butylene group, a 1,3-butylene group or a 1,4-butylene group, etc. Among them, from the viewpoint of base oil solubility, an ethylene group and a 1,2-propylene group or a 1,3-propylene group are preferred, and an ethylene group is more preferred.

[0124] In the general formula (2), -X 5 - is a group represented by -O- or -NH-, and from the viewpoint of antiwear property, a group represented by -O- is preferred.

[0125] As the monomer (b), specifically, examples thereof include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 1-methyl-2-hydroxyethyl (meth)acrylate, 2-methyl-3-hydroxypropyl (meth)acrylate, 2-hydroxy-2-methylpropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-1-methylpropyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, aminobutyl (meth)acrylate, etc.

[0126] Among them, from the aspect of anti-wear property, hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and 2-hydroxy-2-methylpropyl (meth)acrylate are preferred, and hydroxyethyl (meth)acrylate is more preferred.

[0127] In the present invention, from the aspect of base oil solubility, the copolymer (A) preferably contains a monomer (c) represented by the following general formula (3) as a constituent monomer.

[0128] [Chemical formula 5]

[0129]

[0130] [In the general formula (3), R 6 is a hydrogen atom or a methyl group; -X 6 - is a group represented by -O-, -O(AO) m -, or -NH-, A is an alkylene group having 2 to 4 carbon atoms, m is an integer of 1 to 10, and when m is 2 or more, the plurality of As present may be the same or different; R 7 is a linear or branched alkyl group having 5 to 700 carbon atoms.]

[0131] In the monomer (c), R 6 in the general formula (3) is a hydrogen atom or a methyl group, and from the aspect of anti-wear, a methyl group is preferred.

[0132] In the monomer (c), -X 6 - in the general formula (3) is a group represented by -O-, -O(AO) m -, or -NH-.

[0133] A is an alkylene group having 2 to 4 carbon atoms.

[0134] Examples of the alkylene group having 2 to 4 carbon atoms include ethylene, 1,2-propylene or 1,3-propylene, and 1,2-butylene, 1,3-butylene or 1,4-butylene, etc.

[0135] m is an integer from 1 to 10, and from the aspect of solubility in the base oil, it is preferably an integer from 1 to 4, and more preferably an integer from 1 to 2.

[0136] When m is 2 or more, A's can be the same or different, and the (AO) m portion can be randomly bonded or block-bonded.

[0137] As -X 6 -, from the aspect of lubricity, -O- and -O(AO) are preferred m - groups shown, and more preferably -O- and -O(CH2CH2O) m - groups shown.

[0138] In monomer (c), R in the general formula (3) 7 is a linear or branched alkyl group having 5 to 700 carbon atoms.

[0139] Examples of the linear or branched alkyl group having 5 to 700 carbon atoms include pentyl, hexyl, n-octyl, 2-ethylhexyl, n-nonyl, isononyl, n-decyl, isodecyl, n-undecyl, isoundecyl, n-dodecyl, isododecyl, n-tridecyl, isotridecyl, n-tetradecyl, 2-ethyldodecyl, n-pentadecyl, 2-methyltetradecyl, n-hexadecyl, isohexadecyl, n-heptadecyl, isoheptadecyl, 2-ethylpentadecyl, 2-octylnonyl, 2-(3-methylhexyl)-7-methylnonyl, n-octadecyl, isooctadecyl, 2-hexylundecyl, 2-ethylheptadecyl, 1-hexyltridecyl, n-eicosyl, 2-octylundecyl, isoeicosyl, 1-undecyldodecyl, 1-octylpentadecyl, 2-decyltridecyl, n-tetracosyl, 2-decyltetradecyl, 2-dodecylpentadecyl, 2-heptylicosyl, 2-dodecylhexadecyl, n-triacontyl, 2-tetradecyloctadecyl, n-hexatriacontyl, n-tetracontyl, 2-ethyltetracontyl, and polyolefins [such as propylene oligomers or polymers (2 to 233 mers), ethylene / propylene oligomers or polymers (2 to 300 mers), isobutene oligomers or polymers (2 to 175 mers), butadiene oligomers or polymers (2 to 175 mers, and when having double bonds, part or all of the double bonds can be hydrogenated by hydrogenation), etc.].

[0140] The molecular weight or Mn of monomer (c) is preferably 150 to 10,000, more preferably 250 to 9,000, and further preferably 400 to 8,500. When the molecular weight or Mn of monomer (c) is 150 or more, the lubricity tends to be good, and when it is 10,000 or less, the copolymerizability with other monomers tends to be good.

[0141] R in the general formula (3) 7 When it is a residue obtained by removing one hydrogen atom from a polyolefin, from the viewpoint of lubricity, the proportion of butadiene in all the monomers constituting the polyolefin (weight proportion of 1,3-butadiene in all the constituent monomers) is preferably 50% by weight or more, more preferably 75% by weight or more, still more preferably 85% by weight or more, and particularly preferably 90% by weight or more.

[0142] R in the general formula (3) 7 When it is a residue obtained by removing one hydrogen atom from a polyolefin and the polyolefin is a hydrocarbon polymer containing isobutylene and / or 1,2-butylene as essential structural units, from the viewpoint of lubricity, the total amount of isobutylene and 1,2-butylene is preferably 30 mol% or more, more preferably 40 mol% or more, still more preferably 50 mol% or more based on the total number of moles of the structural units of the hydrocarbon polymer.

[0143] The total amount of isobutylene and 1,2-butylene in the hydrocarbon polymer containing isobutylene and / or 1,2-butylene as essential structural units in the general formula (3) can be determined by 13 13C-NMR measurement. Specifically, for example, when using only monomers having 4 carbon atoms as monomers, the hydrocarbon polymer can be analyzed by 13 13C-NMR, and calculated using the following mathematical formula (1) to determine the total mol% of isobutylene and 1,2-butylene based on the total number of moles of the structural units of the hydrocarbon polymer. In 13 13C-NMR, the peak of the methyl group from isobutylene appears at an integral value (integral value A) of 30 to 32 ppm, and the peak of the branched methylene (-CH2CH(CH2CH3)- or -CH(CH2CH3)CH2-) from 1,2-butylene appears at an integral value (integral value B) of 26 to 27 ppm. The total mol% of isobutylene and 1,2-butylene based on the total number of moles of the structural units of the hydrocarbon polymer can be determined from the integral values of the above peaks and the integral value (integral value C) of the peak of the total carbon of the hydrocarbon polymer.

[0144] Total amount of isobutylene and 1,2-butylene (mol%) = 100 × {(integral value A) × 2 + (integral value B) × 4} / (integral value C) (1)

[0145] R 7 When the hydrocarbon polymer in R contains butadiene in the constituent monomers or contains butadiene and 1-butene, from the viewpoints of lubricity and copolymerizability with other monomers, in a part or all of R constituting the general formula (3) 7 of the 7In the structure derived from butadiene or from butadiene and 1-butene, the molar ratio of the 1,2-adduct to the 1,4-adduct (1,2-adduct / 1,4-adduct) is preferably 5 / 95 to 95 / 5, more preferably 20 / 80 to 80 / 20, and still more preferably 30 / 70 to 70 / 30.

[0146] R 7 When the hydrocarbon polymer in contains butadiene in the constituent monomers or contains butadiene and 1-butene, R in the general formula (3) 7 Part or all of R 7 The molar ratio of the 1,2-adduct / 1,4-adduct in the structure derived from butadiene or from butadiene and 1-butene can be determined by 1 H-NMR, 13 C-NMR, Raman spectroscopy, etc.

[0147] From the aspect of solubility in the base oil, the SP value of the structural unit derived from monomer (c) (the structure in which the carbon-carbon double bond of the (meth)acryloyl group in monomer (c) has reacted to form a single bond) is preferably 7.0 to 9.2 (cal / cm 3 ) 1 / 2 , more preferably 7.3 to 8.8 (cal / cm 3 ) 1 / 2 .

[0148] Examples of monomer (c) include (meth)acrylic acid alkyl esters having an alkyl group with 5 to 700 carbon atoms, esterification products of alkylene oxide adducts of alcohols having an alkyl group with 5 to 700 carbon atoms and 2 to 4 carbon atoms with (meth)acrylic acid, and N-alkyl (meth)acrylamides having an alkyl group with 5 to 700 carbon atoms.

[0149] As the linear or branched alkyl group having 5 to 700 carbon atoms, from the aspect of solubility in the base oil, a linear or branched alkyl group having 10 to 600 carbon atoms is preferred, a linear or branched alkyl group having 12 to 100 carbon atoms is more preferred, a linear or branched alkyl group having 16 to 44 carbon atoms is particularly preferred, and a linear alkyl group having 16 to 32 carbon atoms and a branched alkyl group having 18 to 32 carbon atoms are most preferred.

[0150] As the monomer (c), for example, pentyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-undecyl (meth)acrylate, isoundecyl (meth)acrylate, n-dodecyl (meth)acrylate, isododecyl (meth)acrylate, n-tridecyl (meth)acrylate, isotridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, 2-ethyldodecyl (meth)acrylate, n-pentadecyl (meth)acrylate, 2-methyltetradecyl (meth)acrylate, n-hexadecyl (meth)acrylate, isohexadecyl (meth)acrylate, n-heptadecyl (meth)acrylate, isoheptadecyl (meth)acrylate, 2-ethylpentadecyl (meth)acrylate, 2-octylnonyl (meth)acrylate, 2-(3-methylhexyl)-7-methylnonyl (meth)acrylate, n-octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, 2-hexylundecyl (meth)acrylate, 2-ethylheptadecyl (meth)acrylate, 1-hexyltridecyl (meth)acrylate, n-eicosyl (meth)acrylate, 2-octylundecyl (meth)acrylate, isoeicosyl (meth)acrylate, 1-undecyldodecyl (meth)acrylate, 1-octylpentadecyl (meth)acrylate, 2-decyltridecyl (meth)acrylate, n-tetracosyl (meth)acrylate, 2-decyltetradecyl (meth)acrylate, 2-dodecylpentadecyl (meth)acrylate, 2-heptyleicosyl (meth)acrylate, 2-dodecylhexadecyl (meth)acrylate, n-triacontyl (meth)acrylate, 2-tetradecyloctadecyl (meth)acrylate, n-hexatriacontyl (meth)acrylate, n-tetracontyl (meth)acrylate, 2-ethyltetracontyl (meth)acrylate, etc. can be cited.

[0151] The copolymer (A) may also contain monomers other than the above as constituent monomers. For example, it may be a copolymer in which, in addition to the above monomers (a) to (c), one or more monomers selected from the group consisting of (meth)acryloyl monomers (d) having an alkyl group with 1 to 4 carbon atoms, nitrogen atom-containing monomers (e), and hydroxyl group-containing monomers (f) other than the above monomers (a) and (b) are used as constituent monomers.

[0152] Examples of the (meth)acryloyl monomer (d) having an alkyl group with 1 to 4 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-butyl(meth)acrylamide, etc.

[0153] As the (meth)acryloyl monomer (d) having an alkyl group with 1 to 4 carbon atoms, from the viewpoints of anti-wear property and viscosity index improvement effect, (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is preferred, (meth)acrylate having a linear alkyl group with 1 to 4 carbon atoms is more preferred, and methyl (meth)acrylate and butyl (meth)acrylate are particularly preferred.

[0154] Examples of the nitrogen atom-containing monomer (e) include the following monomers (e1) to (e4).

[0155] Amide group-containing monomer (e1):

[0156] Examples include (meth)acrylamide, monoalkylaminoalkyl (meth)acrylamide [(meth)acrylamide having an aminoalkyl (2 to 6 carbon atoms) with 1 alkyl group having 1 to 4 carbon atoms bonded to the nitrogen atom; for example, N-methylaminoethyl (meth)acrylamide, N-ethylaminoethyl (meth)acrylamide, N-isopropylaminon-butyl (meth)acrylamide, and N-n- or isobutylaminon-butyl (meth)acrylamide, etc.], dialkylamino (meth)acrylamide [(meth)acrylamide having 2 alkyl groups with 1 to 4 carbon atoms bonded to the nitrogen atom; for example, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, and N,N-di-n-butyl (meth)acrylamide, etc.], dialkylaminoalkyl (meth)acrylamide [(meth)acrylamide having an aminoalkyl (2 to 6 carbon atoms) with 2 alkyl groups having 1 to 4 carbon atoms bonded to the nitrogen atom; for example, N,N-dimethylaminoethyl (meth)acrylamide, N,N-diethylaminoethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, and N,N-di-n-butylaminobutyl (meth)acrylamide, etc.], N-vinylcarboxamide [N-vinylformamide, N-vinylacetamide, N-vinyl-n-propionamide, or N-vinylisopropionamide, and N-vinylhydroxyacetamide, etc.] and other monomers having only nitrogen atoms in the amide group.

[0157] Nitro group-containing monomer (e2):

[0158] Examples include 4-nitrostyrene and the like.

[0159] Monomers (e3) containing primary to tertiary amino groups:

[0160] Examples of vinyl monomers containing primary amino groups include alkenylamines having 3 to 6 carbon atoms [(meth)allylamine, crotonamine, etc.], (meth)acrylic acid aminoalkyl esters having 2 to 6 carbon atoms [(meth)acrylic acid aminoethyl ester, etc.]; vinyl monomers containing secondary amino groups include (meth)acrylic acid monoalkylaminoalkyl esters [esters of (meth)acrylic acid with aminoalkyl groups having 2 to 6 carbon atoms in which one alkyl group having 1 to 6 carbon atoms is bonded to the nitrogen atom; for example, tert-butylaminoethyl (meth)acrylate and methylaminoethyl (meth)acrylate, etc.], dieneylamines having 6 to 12 carbon atoms [di(meth)allylamine, etc.]; vinyl monomers containing tertiary amino groups include (meth)acrylic acid dialkylaminoalkyl esters [esters of (meth)acrylic acid with aminoalkyl groups having 2 to 6 carbon atoms in which two alkyl groups having 1 to 6 carbon atoms are bonded to the nitrogen atom; for example, N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate, etc.], alicyclic (meth)acrylic acid esters having a nitrogen atom [(meth)acrylic acid morpholinylethyl ester, etc.], aromatic vinyl monomers [N,N-diphenylaminoethyl (meth)acrylamide, N,N-dimethylaminostyrene, 4-vinylpyridine, 2-vinylpyridine, N-vinylpyrrole, N-vinylpyrrolidone, N-vinylthiopyrrolidone, etc.], and their hydrochloride salts, sulfate salts, phosphate salts, or salts with lower alkyl (1 to 8 carbon atoms) monocarboxylic acids (acetic acid, propionic acid, etc.).

[0161] Monomers (e4) containing a nitrile group:

[0162] Examples include (meth)acrylonitrile and the like.

[0163] Among the vinyl monomers (e) containing a nitrogen atom, preferred are monomers (e1) containing an amide group and monomers (e3) containing primary to tertiary amino groups, and more preferably N,N-diphenylaminoethyl (meth)acrylamide, dimethylaminoethyl (meth)acrylamide, diethylaminoethyl (meth)acrylamide, dimethylaminopropyl (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, and N,N-diethylaminoethyl (meth)acrylate.

[0164] As monomers (f) containing a hydroxyl group, the following substances can be specifically cited.

[0165] Examples thereof include aromatic monomers having a hydroxyl group (such as p-hydroxystyrene), dihydroxyalkyl (C1-C4) substituted (meth)acrylamides [N,N-dihydroxymethyl (meth)acrylamide, N,N-dihydroxypropyl (meth)acrylamide, N,N-di-2-hydroxybutyl (meth)acrylamide, etc.], vinyl alcohol, enols having 3 to 12 carbon atoms [(meth)allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1-octenol, 1-undecenol, etc.], olefin monohydric alcohols or olefin dihydric alcohols having 4 to 12 carbon atoms [1-butene-3-ol, 2-butene-1-ol, 2-butene-1,4-diol, etc.], hydroxyalkyl (C1-C6) alkenyl (C3-C10) ethers (such as 2-hydroxyethyl propenyl ether), and alkenyl (C3-C10) ethers or (meth)acrylates of polyhydric (3-8 membered) alcohols (such as glycerin, pentaerythritol, sorbitol, sorbitan, diglycerol, saccharides, sucrose, etc.) [such as sucrose (meth)allyl ether, etc.].

[0166] The copolymer (A) may also use the following monomers (g) to (n) as constituent monomers.

[0167] Alkoxyalkyl ether monomer (g):

[0168] This is a monomer other than monomer (c). Examples thereof include (meth)acrylic acid alkoxyalkyl esters having an alkyl group with 1 to 4 carbon atoms {such as methoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, methoxybutyl (meth)acrylate, methoxyheptyl (meth)acrylate, methoxyhexyl (meth)acrylate, methoxypentyl (meth)acrylate, methoxyoctyl (meth)acrylate, ethoxyethyl (meth)acrylate, ethoxypropyl (meth)acrylate, ethoxybutyl (meth)acrylate, ethoxyheptyl (meth)acrylate, ethoxyhexyl (meth)acrylate, ethoxypentyl (meth)acrylate, ethoxyoctyl (meth)acrylate, propoxymethyl (meth)acrylate, propoxyethyl (meth)acrylate, propoxypropyl (meth)acrylate, propoxybutyl (meth)acrylate, propoxyheptyl (meth)acrylate, propoxyhexyl (meth)acrylate, propoxypentyl (meth)acrylate, propoxyoctyl (meth)acrylate, butoxymethyl (meth)acrylate, butoxyethyl (meth)acrylate, butoxypropyl (meth)acrylate, butoxybutyl (meth)acrylate, butoxyheptyl (meth)acrylate, butoxyhexyl (meth)acrylate, butoxypentyl (meth)acrylate, butoxyoctyl (meth)acrylate, etc.} and the like.

[0169] Among the monomer (g), methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and butoxyethyl (meth)acrylate are preferred.

[0170] Aliphatic hydrocarbon monomer (h):

[0171] Examples include olefins having 2 to 20 carbon atoms (such as ethylene, propylene, butene, isobutene, pentene, heptene, diisobutene, octene, dodecene, and octadecene) and diolefins having 4 to 12 carbon atoms (such as butadiene, isoprene, 1,4-pentadiene, 1,6-heptadiene, and 1,7-octadiene).

[0172] Alicyclic hydrocarbon monomer (i):

[0173] Examples include cyclohexene, (bi)cyclopentadiene, pinene, limonene, vinylcyclohexene, and ethylidenebicycloheptene.

[0174] Aromatic hydrocarbon monomer (j):

[0175] Examples include styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, 4-ethylstyrene, 4-isopropylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-cyclohexylstyrene, 4-benzylstyrene, indene, 4-crotylbenzene, and 2-vinylnaphthalene.

[0176] Vinyl esters, vinyl ethers, and vinyl ketones (k):

[0177] Examples include vinyl esters of saturated fatty acids having 2 to 12 carbon atoms (such as vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl octanoate), alkyl, aryl, or alkoxyalkyl vinyl ethers having 1 to 12 carbon atoms (such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, phenyl vinyl ether, vinyl-2-methoxyethyl ether, and vinyl-2-butoxyethyl ether), and alkyl or aryl vinyl ketones having 1 to 8 carbon atoms (such as methyl vinyl ketone, ethyl vinyl ketone, and phenyl vinyl ketone).

[0178] Epoxy group-containing monomer (l):

[0179] Examples include glycidyl (meth)acrylate and glycidyl (meth)allyl ether.

[0180] Halogen element-containing monomer (m):

[0181] Examples include vinyl chloride, vinyl bromide, vinylidene chloride, (meth)allyl chloride, and halogenated styrene (such as dichlorostyrene).

[0182] Esters of unsaturated polycarboxylic acids (n):

[0183] Examples thereof include alkyl, cycloalkyl or aralkyl esters of unsaturated polycarboxylic acids [dialkyl esters having 1 to 8 carbon atoms of unsaturated dicarboxylic acids (such as maleic acid, fumaric acid and itaconic acid) (dimethyl maleate, dimethyl fumarate, diethyl maleate and dioctyl maleate), etc.].

[0184] Regarding the weight ratio of monomer (a) in the monomers constituting copolymer (A), from the aspect of antiwear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 12.5 to 50% by weight, more preferably 20 to 45% by weight, and particularly preferably 25 to 40% by weight.

[0185] Regarding the weight ratio of monomer (b) in the monomers constituting copolymer (A), from the aspect of antiwear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 0.08 to 2.7% by weight, more preferably 0.4 to 1.9% by weight, and particularly preferably 0.5 to 1.5% by weight.

[0186] Regarding the total weight ratio of monomer (a) and monomer (b) in the monomers constituting copolymer (A), from the aspect of antiwear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 13 to 52% by weight, more preferably 20.5 to 46% by weight, and particularly preferably 26 to 41% by weight.

[0187] The weight ratio (b / a) of the above monomer (b) to the above monomer (a) in the monomers constituting copolymer (A) is 0.0005 to 0.12, preferably 0.02 to 0.064, more preferably 0.03 to 0.055, and particularly preferably 0.03 to 0.045.

[0188] If the above weight ratio is less than 0.0005, the antiwear effect cannot be obtained, and if it exceeds 0.12, the antiwear effect is insufficient.

[0189] Regarding the weight ratio of monomer (c) in the monomers constituting copolymer (A), from the aspect of solubility, based on the total weight of the monomers constituting copolymer (A), it is preferably 48 to 87% by weight, more preferably 54 to 80% by weight, still more preferably 54 to 72% by weight, and particularly preferably 59 to 72% by weight.

[0190] Regarding the weight ratio of monomer (d) in the monomers constituting copolymer (A), from the aspect of antiwear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 0 to 30% by weight, more preferably 5 to 15% by weight.

[0191] Regarding the total weight ratio of monomer (e) and monomer (f) in the monomers constituting copolymer (A), from the aspect of anti-wear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 20% by weight or less, more preferably 10% by weight or less.

[0192] Regarding the weight ratio of monomers (g) to (n) in the monomers constituting copolymer (A), from the aspect of anti-wear property, based on the total weight of the monomers constituting copolymer (A), it is preferably 10% by weight or less, more preferably 7% by weight or less.

[0193] The weight ratio of each of monomers (a) to (n) in copolymer (A) can be measured by methods such as pyrolysis GC / MS. In addition, the weight ratio of each constituent monomer at the time of charging in the production of copolymer (A) can also be used as the weight ratio of each of monomers (a) to (n) in copolymer (A).

[0194] From the aspect of base oil solubility, the SP value of copolymer (A) is preferably 8.5 to 11.5 (cal / cm 3 ) 1 / 2 , more preferably 8.7 to 11.0 (cal / cm 3 ) 1 / 2 , still more preferably 8.9 to 10.5 (cal / cm 3 ) 1 / 2 , particularly preferably 9.2 to 10.2 (cal / cm 3 ) 1 / 2 .

[0195] The SP value of copolymer (A) refers to the SP value of the structural units derived from each monomer constituting copolymer (A) (the structure in which the polymerizable groups (such as vinyl groups) contained in each monomer constituting copolymer (A) have become single bonds through polymerization reaction), and is a value obtained by arithmetic averaging based on the weight fractions of each constituent monomer at the time of charging. For example, in the case where the monomer is methyl methacrylate, in the structural unit derived from methyl methacrylate, in terms of atomic groups, there are 2 CH3, 1 CH2, 1 C, and 1 CO2. Therefore, it can be known from the following mathematical formula that the SP value of the structural unit derived from methyl methacrylate is 9.933 (cal / cm 3 ) 1 / 2 . Similarly, by calculation, it can be known that the SP value of the structural unit derived from ethyl methacrylate is 9.721 (cal / cm 3 ) 1 / 2 .

[0196] ΣΔe i =1125×2 + 1180 + 350 + 4300 = 8080

[0197] Σv i = 33.5 × 2 + 16.1 - 19.2 + 18.0 = 81.9

[0198] δ = (8080 / 81.9) 1 / 2 = 9.933 (cal / cm 3 ) 1 / 2

[0199] When the polymer is a polymer of 50 wt% methyl methacrylate and 50 wt% ethyl methacrylate, the SP value of the polymer is calculated as follows by arithmetic mean based on the weight fractions of the SP values of the structural units from each monomer.

[0200] SP value of the polymer = (9.933 × 50 + 9.721 × 50) / 100 = 9.827

[0201] The SP value of the copolymer (A) can be adjusted to a desired range by appropriately adjusting the monomers and weight fractions used. Specifically, by using more monomers with a larger number of carbon atoms in the alkyl group, the SP value can be reduced, and by using more monomers with a smaller number of carbon atoms in the alkyl group, the SP value can be increased.

[0202] From the aspect of abrasion resistance, the weight average molecular weight (hereinafter simply referred to as Mw) of the copolymer (A) is preferably 0.5 × 10^4 to 50 × 10^4, more preferably 1 × 10^4 to 15 × 10^4.

[0203] It should be noted that Mw can be measured by gel permeation chromatography under the following conditions.

[0204] <Measurement conditions for Mw of copolymer (A)>

[0205] Apparatus: "HLC - 8320GPC" [manufactured by Tosoh Corporation]

[0206] Column: "Guardcolumn Super HZM - M" [manufactured by Tosoh Corporation] 1 piece, "TSKgel Super HZM - M" [manufactured by Tosoh Corporation] 3 pieces

[0207] Measurement temperature: 40 °C

[0208] Sample solution: 0.25 wt% tetrahydrofuran solution

[0209] Solution injection volume: 100 μl

[0210] Detection device: Refractive index detection G

[0211] Reference substance: 12 kinds of standard polystyrene (TSK standard POLYSTYRENE) (molecular weights: 500, 1,050, 2,800, 5,970, 9,100, 18,100, 37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000) [manufactured by Tosoh Corporation]

[0212] The copolymer (A) can be obtained by a known production method. Specifically, a method of solution polymerization of the above monomers in a solvent in the presence of a polymerization catalyst can be cited.

[0213] Examples of the solvent include toluene, xylene, alkylbenzenes having 9 to 10 carbon atoms, methyl ethyl ketone, ethyl acetate, 2-propanol, and the base oil described below, etc.

[0214] Examples of the polymerization catalyst include azo catalysts (such as azobisisobutyronitrile and azodipentanenitrile), peroxide catalysts (such as benzoyl peroxide, cumyl peroxide, and lauryl peroxide), and redox catalysts (such as a mixture of benzoyl peroxide and a tertiary amine). A known chain transfer agent (such as an alkyl mercaptan having 2 to 20 carbon atoms) can also be further used as needed.

[0215] The polymerization temperature is preferably 25 to 140 °C, more preferably 50 to 120 °C. In addition to the above solution polymerization, the copolymer (A) can also be obtained by bulk polymerization, emulsion polymerization, or suspension polymerization.

[0216] As the polymerization form when the copolymer (A) is a copolymer, it can be either a random addition polymer or an alternating copolymer. In addition, it can be either a graft copolymer or a block copolymer.

[0217] The antiwear agent of the present invention only needs to contain the above copolymer (A). From the aspect of operability (such as ease of addition to the lubricating oil composition), a base oil can be further contained.

[0218] Examples of the base oil include mineral oil (solvent-refined oil, paraffinic oil, high-viscosity-index oil containing isoparaffin, high-viscosity-index oil obtained by hydrocracking based on isoparaffin, and naphthenic oil, etc.), synthetic lubricating oil [hydrocarbon-based synthetic lubricating oil (such as poly-α-olefin-based synthetic lubricating oil, etc.) and ester-based synthetic lubricating oil, etc.], and mixtures thereof. Among them, mineral oil is preferred from the aspect of insulation.

[0219] Regarding the content of the copolymer (A) in the antiwear agent, from the aspect of operability (such as ease of addition to the lubricating oil composition), based on the weight of the antiwear agent, it is preferably 20 to 80% by weight, more preferably 40 to 70% by weight.

[0220] Regarding the content of the base oil in the anti-wear agent, from the aspect of operability (such as ease of addition to the lubricating oil composition, etc.), based on the weight of the anti-wear agent, it is preferably 20 to 80% by weight, more preferably 30 to 60% by weight.

[0221] The anti-wear agent of the present invention can balance anti-wear performance and storage stability, and thus is suitable for use in gear oils (differential oils and industrial gear oils, etc.), MTF, transmission oils [ATF and belt-type CVTF, etc.], traction oils (ring-type CVTF, etc.), shock absorber oils, power steering oils, hydraulic oils (hydraulic oils for construction machinery and industrial hydraulic oils, etc.) and engine oils, etc. It is preferably used as an anti-wear agent for transmission oils, motor oils, and transmission and motor combined oils in electric vehicles or hybrid vehicles, and particularly preferably used as an anti-wear agent for transmission and motor combined oils in electric vehicles or hybrid vehicles.

[0222] <Lubricating oil composition>

[0223] The lubricating oil composition of the present invention contains the above-mentioned anti-wear agent of the present invention and a base oil. As the base oil, when the base oil is included in the anti-wear agent, the same base oil as that in the anti-wear agent can be used, or a different one can be used.

[0224] Examples of the base oil used in the lubricating oil composition include mineral oils (solvent-refined oils, paraffinic oils, high-viscosity-index oils containing isoparaffins, high-viscosity-index oils obtained by hydrocracking based on isoparaffins, and naphthenic oils, etc.), synthetic lubricating oils [hydrocarbon-based synthetic lubricating oils (poly-α-olefin-based synthetic lubricating oils, etc.) and ester-based synthetic lubricating oils, etc.] and mixtures thereof. Among them, from the aspect of insulation, mineral oil is preferred.

[0225] From the aspect of the solubility of the copolymer (A), the kinematic viscosity of the base oil at 100 °C (kinematic viscosity measured according to JIS-K2283 (2000)) is preferably 1 to 10 mm 2 / s, more preferably 1 to 4 mm 2 / s.

[0226] From the aspect of the viscosity index improvement effect, the viscosity index of the base oil (viscosity index measured according to JIS-K2283 (2000)) is preferably 100 or more, more preferably 110 or more.

[0227] The cloud point of the base oil (cloud point measured according to JIS-K2269 (1987)) is preferably -5 °C or lower, more preferably -15 °C or lower. If the cloud point of the base oil is within this range, the low-temperature viscosity of the lubricating oil composition is good.

[0228] From the aspect of compatibility, the absolute value (ΔSP) of the difference between the SP value of the copolymer (A) in the lubricating oil composition and the SP value of the base oil is preferably 0.5 to 3.2 (cal / cm 3 ) 1 / 2 and more preferably 0.6 to 2.5 (cal / cm 3 ) 1 / 2 and particularly preferably 0.6 to 2.1 (cal / cm 3 ) 1 / 2 and most preferably 0.7 to 1.9 (cal / cm 3 ) 1 / 2 .

[0229] Regarding the content of the copolymer (A) in the lubricating oil composition of the present invention, from the aspect of anti-wear property, based on the weight of the lubricating oil composition, it is preferably 0.1 to 30% by weight, more preferably 0.1 to 20% by weight, and particularly preferably 0.1 to 10% by weight.

[0230] For the lubricating oil composition of the present invention, except that the test conditions are as described below, the maximum seizure load (N) measured according to ASTM D 2783 can be 750 N or more.

[0231] <Measurement conditions>

[0232] Equipment: KRL & Four-ball tester of SPACE CREATION

[0233] Ball: Steel ball for four-ball bearing, size: 1 / 2

[0234] Speed: 1760 rpm

[0235] Temperature: 25 °C

[0236] Test time for one time: 10 seconds

[0237] Test start load: 500 N

[0238] Load increase interval: 10 N

[0239] The lubricating oil composition of the present invention can be a lubricating oil composition used under high load conditions such as 750 N or more.

[0240] The lubricating oil composition of the present invention is suitable for use in gear oils (differential oils, industrial gear oils, etc.), MTFs, transmission oils [ATFs, belt-type CVTFs, etc.], traction oils (ring-type CVTFs, etc.), shock absorber oils, power steering oils, hydraulic oils (hydraulic oils for construction machinery, industrial hydraulic oils, etc.), and engine oils, etc. It is preferably useful as a transmission oil, an electric motor oil, or an oil that can be used for both a transmission and an electric motor in an electric vehicle or a hybrid vehicle, and is particularly preferably useful as an oil that can be used for both a transmission and an electric motor in an electric vehicle or a hybrid vehicle.

[0241] The lubricating oil composition of the present invention may contain various additives. As additives, the following additives can be mentioned.

[0242] (1) Viscosity index improvers:

[0243] (Meth)acrylic acid alkyl esters having 1 to 7 carbon atoms (hereinafter sometimes abbreviated as C) / (meth)acrylic acid linear or branched alkyl esters having 8 to 40 carbon atoms copolymer, dispersion monomers (amine monomers, etc.) / (meth)acrylic acid alkyl esters having 1 to 7 carbon atoms / (meth)acrylic acid linear or branched alkyl esters having 8 to 40 carbon atoms copolymer, hydroxyl group-containing monomers / (meth)acrylic acid alkyl esters having 1 to 7 carbon atoms / (meth)acrylic acid linear or branched alkyl esters having 8 to 40 carbon atoms copolymer, comb-shaped polymers [(meth)acrylic acid alkyl esters having 1 to 7 carbon atoms / (meth)acrylic acid linear or branched alkyl esters having 8 to 40 carbon atoms / polyolefin macromonomers], ethylene / (meth)acrylic acid alkyl esters having 1 to 18 carbon atoms copolymer, polyisobutylene, polyalkylstyrene, ethylene / propylene copolymer, styrene / maleate copolymer, styrene / isoprene hydrogenated copolymer, etc.;

[0244] (2) Detergents:

[0245] Basic, overbased or neutral metal salts [overbased or alkaline earth metal salts of sulfonates (petroleum sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, etc.)], salicylates, phenates, naphthenates, carbonates, phosphonates, and mixtures thereof;

[0246] (3) Dispersants:

[0247] Succinimides (bis- or mono-polybutenyl succinimides), Mannich condensates, borates, etc.;

[0248] (4) Antioxidants:

[0249] Hindered phenols, aromatic secondary amines, etc.;

[0250] (5) Oiliness improvers:

[0251] Long-chain fatty acids and their esters (such as oleic acid and oleic acid esters), long-chain amines and their amides (such as oleylamine and oleamide), etc.;

[0252] (6) Metal-based friction and wear modifiers:

[0253] Molybdenum-based and zinc-based compounds (such as molybdenum dialkyldithiophosphate, molybdenum dithiocarbamate, and zinc dialkyldithiophosphate), etc.;

[0254] (7) Extreme pressure agents:

[0255] Sulfur-based compounds (such as monosulfide or disulfide, sulfoxide, and sulfur-phosphorus compounds), phosphorus compounds, and chlorine-based compounds (such as chlorinated alkanes), etc.;

[0256] (8) Antifoaming agents:

[0257] Silicone oil, metal soaps, fatty acid esters, and phosphate ester compounds, etc.;

[0258] (9) Demulsifiers:

[0259] Quaternary ammonium salts (such as tetraalkylammonium salts), sulfated oils, and phosphate esters (such as phosphate esters of nonionic surfactants containing polyoxyethylene), etc.;

[0260] (10) Corrosion inhibitors:

[0261] Compounds containing nitrogen atoms (such as benzotriazole and 1,3,4-thiadiazolyl-2,5-bis(dialkyldithiocarbamate)), etc.;

[0262] (11) Pour point depressants:

[0263] Alkyl polymethacrylates, alkyl polyacrylates, polyalkylstyrenes, polyvinyl acetates, etc.

[0264] The lubricating oil composition of the present invention preferably contains at least one selected from the group consisting of viscosity index improvers, detergents, dispersants, antioxidants, oiliness improvers, metal-based friction and wear modifiers, extreme pressure agents, antifoaming agents, demulsifiers, corrosion inhibitors, and pour point depressants. The lubricating oil composition may contain only one of these additives, or may contain two or more additives as needed.

[0265] Based on the total amount of the lubricating oil composition, the content of each of these additives is preferably 0.1 to 15% by weight. In addition, based on the total amount of the lubricating oil composition, the total content of the additives is preferably 0.1 to 30% by weight, more preferably 0.3 to 20% by weight, and further preferably 3 to 10% by weight.

[0266] The following matters are disclosed in this specification.

[0267] The present disclosure (1) relates to an antiwear agent which is an antiwear agent of a copolymer (A) containing a monomer (a) represented by the following general formula (1) and a monomer (b) represented by the following general formula (2) as essential constituent monomers, wherein the weight ratio (b / a) of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005 to 0.12.

[0268] [Chemical formula 6]

[0269]

[0270] [In general formula (1), A 1 is a polymerizable group; -X 1 -, -X 2 -, and -X 3 - are each independently a group represented by -O- or -NH-; R 1 is an alkylene group having 1 to 4 carbon atoms; R 2 is an alkylene group having 2 to 20 carbon atoms; R 3 is a hydrogen atom, a straight-chain or branched-chain alkyl group having 1 to 44 carbon atoms, a phenyl group having a straight-chain or branched-chain alkyl group having 1 to 44 carbon atoms, an acyl group having a straight-chain or branched-chain alkyl group having 1 to 44 carbon atoms, or a benzoyl group having a straight-chain or branched-chain alkyl group having 1 to 44 carbon atoms; p is an integer from 1 to 100, and when p is 2 or more, multiple R 2 and X 3 may each be the same or different.]

[0271] [Chemical formula 7]

[0272]

[0273] [In general formula (2), R 4 is a hydrogen atom or a methyl group; -X 4 - is a group represented by -O- or -NH-; R 5 is an alkylene group having 1 to 4 carbon atoms; -X 5 - is a group represented by -O- or -NH-.]

[0274] The present disclosure (2) relates to the antiwear agent described in the present disclosure (1), wherein the copolymer (A) is a copolymer containing a monomer (c) represented by the following general formula (3) as a constituent monomer.

[0275] [Chemical formula 8]

[0276]

[0277] [In general formula (3), R 6 is a hydrogen atom or a methyl group; -X 6- is -O-, -O(AO) m - or a group represented by -NH-, A is an alkylene group having 2 to 4 carbon atoms, m is an integer of 1 to 10, and when m is 2 or more, the plurality of As present may be the same or different; R 7 is a linear or branched alkyl group having 5 to 700 carbon atoms.]

[0278] The present disclosure (3) relates to the antiwear agent described in the present disclosure (1) or (2), wherein the weight average molecular weight of the copolymer (A) is 0.5×10⁴ to 50×10⁴.

[0279] The present disclosure (4) relates to a lubricating oil composition comprising the antiwear agent described in any one of the present disclosures (1) to (3) and a base oil.

[0280] The present disclosure (5) relates to the lubricating oil composition described in the present disclosure (4), wherein the kinematic viscosity of the base oil at 100 °C is 1 mm 2 / s to 4 mm 2 / s.

[0281] The present disclosure (6) relates to the lubricating oil composition described in the present disclosure (4) or (5), which further contains at least one selected from the group consisting of a viscosity index improver, a detergent, a dispersant, an antioxidant, an oiliness improver, a metal-based friction and wear modifier, an extreme pressure agent, an antifoaming agent, an anti-emulsifier, a corrosion inhibitor, and a pour point depressant.

[0282] Examples

[0283] The present invention will be described in detail below by way of examples, but the present invention is not limited thereto.

[0284] <Production Example 1> [Production of Monomer (a-1)]

[0285] 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), 684.8 parts by weight (6.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged into a reaction vessel equipped with a temperature regulator, a stirring blade, a decompression device, a snake-shaped condenser, a fractionating tube, a distillate receiving flask, a nitrogen gas inlet, and an outlet. While introducing air, the temperature was raised to 115 °C with stirring. Then, the reaction was carried out at 115 °C for 8 hours to separate the distilled water. It was further cooled to 25 °C, and the esterification reaction product (yield 100 mol%) was confirmed by 1 ¹H-NMR.

[0286] Monomer (a-1) has A in the general formula (1) 1 being methacryloyl, -X 1 -, -X2 - and -X 3 - is the group represented by -O-, R 1 is ethylene, the molar average value of p = 3, R 2 = pentamethylene, R 3 The monomer represented by a hydrogen atom has an SP value of 11.04.

[0287] <Production Example 2> [Production of monomer (a-2)]

[0288] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a snake-shaped condenser, a fractionating tube, a distillate receiving flask, a nitrogen gas inlet, and an outlet, 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (HEMA), 913.2 parts by weight (8.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged, and the mixture was heated to 115 °C with stirring while introducing air. Then, the reaction was carried out at 115 °C for 8 hours, and the distilled water was separated. Further cooled to 25 °C, and the esterification reaction product (yield 100 mol%) was confirmed by 1 1H-NMR.

[0289] Monomer (a-2) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is the group represented by -O-, R 1 is ethylene, the molar average value of p = 4, R 2 = pentamethylene, R 3 The monomer represented by a hydrogen atom has an SP value of 10.87.

[0290] <Production Example 3> [Production of monomer (a-3)]

[0291] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a snake-shaped condenser, a fractionating tube, a distillate receiving flask, a nitrogen gas inlet, and an outlet, 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (HEMA), 228.3 parts by weight (2.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged, and the mixture was heated to 115 °C with stirring while introducing air. Then, the reaction was carried out at 115 °C for 8 hours, and the distilled water was separated. Further cooled to 25 °C, and the esterification reaction product (yield 53 mol%) was confirmed by 1 1H-NMR. Thereafter, 2-hydroxyethyl methacrylate (HEMA) remaining as an impurity in 47 mol% was removed by silica gel column chromatography.

[0292] The monomer (a-3) is A in the general formula (1). 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is the group represented by -O-, R 1 is ethylene, the molar average value of p = 1.9, R 2 = pentamethylene, R 3 The monomer represented by a hydrogen atom has an SP value of 11.36.

[0293] <Production Example 4> [Production of monomer (a-4)]

[0294] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a serpentine condenser, a fractionating column, a distillate receiving flask, a nitrogen gas inlet, and an outlet, 232.2 parts by weight (2.0 mol parts) of 2-hydroxyethyl acrylate (hereinafter abbreviated as HEA), 456.6 parts by weight (4.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged. While introducing air, the temperature was raised to 115°C with stirring. Then, the reaction was carried out at 115°C for 8 hours, and the distilled water was separated. It was further cooled to 25°C, and 1 1H-NMR was used to confirm the esterification reaction product (yield 76 mol%). After that, 24 mol% of 2-hydroxyethyl acrylate (HEA) remaining as an impurity was removed by silica gel column chromatography.

[0295] The monomer (a-4) is A in the general formula (1). 1 is acryloyl, -X 1 -, -X 2 -, and -X 3 - is the group represented by -O-, R 1 is ethylene, the molar average value of p = 2.6, R 2 = pentamethylene, R 3 The monomer represented by a hydrogen atom has an SP value of 11.30.

[0296] <Production Example 5> [Production of monomer (a-5)]

[0297] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a serpentine condenser, a fractionating tube, a flask for receiving distillate, a nitrogen gas inlet, and an outlet, 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (HEMA), 1141.5 parts by weight (10.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged, and the temperature was raised to 115 °C with stirring while passing air. Subsequently, the reaction was carried out at 115 °C for 8 hours, and the distilled water was separated. It was further cooled to 25 °C, and the esterification reaction product (yield 100 mol%) was confirmed by 1 1H-NMR.

[0298] Monomer (a-5) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is a group represented by -O-, R 1 is ethylene, the molar average value of p = 5, R 2 = pentamethylene, R 3 is a monomer represented by a hydrogen atom, and the SP value is 10.75.

[0299] <Production Example 6> [Production of monomer (a-6)]

[0300] A mixture of 54.3 parts by weight (10 mol parts) of the monomer (a-2) obtained by the method described in Production Example 2, 18.5 parts by weight (10 mol parts) of lauric acid, and 350 parts by weight of dichloromethane was stirred at 0 °C. Subsequently, 5.6 parts by weight (5 mol parts) of 4-dimethylaminopyridine and 21.5 parts by weight (15 mol parts) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was heated to room temperature and stirred overnight in this state. The reaction solution was washed with 1N hydrochloric acid, an aqueous sodium bicarbonate solution, and brine, and then the organic layer was dried over magnesium sulfate. Then, the solvent was removed, and the product was further dried under vacuum to obtain the monomer (a-6).

[0301] Monomer (a-6) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is a group represented by -O-, R 1 is ethylene, the molar average value of p = 4, R 2 = pentamethylene, R 3 is a monomer represented by dodecanoyl, and the SP value is 9.68.

[0302] <Production Example 7> [Production of monomer (a-7)]

[0303] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a serpentine condenser, a fractionating tube, a flask for receiving distillate, a nitrogen gas inlet, and an outlet, 232.2 parts by weight (2.0 mol parts) of 2-hydroxyethyl acrylate (hereinafter abbreviated as HEA), 2283.0 parts by weight (20.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged, and the temperature was raised to 115°C with stirring while introducing air. Then, the reaction was carried out at 115°C for 8 hours, and the distilled water was separated. It was further cooled to 25°C, and the esterification reaction product (yield 100 mol%) was confirmed by 1 1H-NMR.

[0304] Monomer (a-7) is A in the general formula (1) 1 is an acryloyl group, -X 1 -, -X 2 - and -X 3 - is a group represented by -O-, R 1 is an ethylene group, the molar average value of p = 10, R 2 = a pentamethylene group, R 3 is a monomer represented by a hydrogen atom, and the SP value is 10.68.

[0305] <Production Example 8> [Production of Monomer (a-8)]

[0306] Into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a serpentine condenser, a fractionating tube, a flask for receiving distillate, a nitrogen gas inlet, and an outlet, 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (HEMA), 4566.0 parts by weight (40.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged, and the temperature was raised to 115°C with stirring while introducing air. Then, the reaction was carried out at 115°C for 8 hours, and the distilled water was separated. It was further cooled to 25°C, and the esterification reaction product (yield 100 mol%) was confirmed by 1 1H-NMR.

[0307] Monomer (a-8) is A in the general formula (1) 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - is a group represented by -O-, R 1 is an ethylene group, the molar average value of p = 20, R 2 = a pentamethylene group, R 3 is a monomer represented by a hydrogen atom, and the SP value is 11.32.

[0308] <Production Example 9>[Production of Monomer (a-9)]

[0309] A mixture of 60.6 parts by weight (10 mol parts) of monomer (a-2) obtained by the method described in Production Example 2, 9.1 parts by weight (10 mol parts) of n-butyric acid, and 350 parts by weight of dichloromethane was stirred at 0 °C. Subsequently, 6.3 parts by weight (5 mol parts) of 4-dimethylaminopyridine and 24.0 parts by weight (15 mol parts) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was heated to room temperature and stirred overnight in this state. The reaction solution was washed with 1N hydrochloric acid, aqueous sodium hydrogen carbonate solution, and brine, and the organic layer was dried over magnesium sulfate. Then, the solvent was removed, and the product was further dried under vacuum to obtain monomer (a-9).

[0310] Monomer (a-9) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is a group represented by -O-, R 1 is ethylene, the molar average value of p = 4, R 2 = pentylene, R 3 is a monomer represented by butyryl group, and the SP value is 9.96.

[0311] <Production Example 10>[Production of Monomer (a-10)]

[0312] 260.3 parts by weight (2.0 mol parts) of 2-hydroxyethyl methacrylate (HEMA), 1598.1 parts by weight (14.0 mol parts) of ε-caprolactone, 3.7 parts by weight (0.03 mol parts) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were charged into a reaction vessel equipped with a temperature regulator, stirring blades, a decompression device, a reflux condenser, a fractionating column, a distillate receiving flask, a nitrogen gas inlet, and an outlet, and the temperature was raised to 115 °C with stirring while passing air. Subsequently, the reaction was carried out at 115 °C for 8 hours to separate the distilled water. It was further cooled to 25 °C to obtain monomer (a'-10) as a precursor of monomer (a-10).

[0313] Monomer (a'-10) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is a group represented by -O-, R 1 is ethylene, the molar average value of p = 7, R 2 = pentylene, R 3 is a monomer represented by a hydrogen atom.

[0314] A mixture of 70.9 parts by weight (10 mol parts) of the obtained monomer (a'-10), 6.7 parts by weight (10 mol parts) of n-butyric acid, and 350 parts by weight of dichloromethane was stirred at 0 °C. Then, 4.7 parts by weight (5 mol parts) of 4-dimethylaminopyridine and 17.8 parts by weight (15 mol parts) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was heated to room temperature and stirred overnight in this state. The reaction solution was washed with 1N hydrochloric acid, aqueous sodium bicarbonate solution, and brine, and the organic layer was dried over magnesium sulfate. Then, the solvent was removed, and the product was further dried under vacuum to obtain monomer (a-10).

[0315] Monomer (a-10) is A in the general formula (1) 1 is methacryloyl, -X 1 -, -X 2 -, and -X 3 - is a group represented by -O-, R 1 is ethylene, the molar average value of p = 7, R 2 = pentamethylene, R 3 is a monomer represented by butyryl group, and the SP value is 10.40.

[0316] <Examples 1 to 25, Comparative Examples 1 to 4>

[0317] 185 parts by weight of ethyl acetate, 100 parts by weight of a mixture of various monomers described in Tables 2 to 3, dodecyl mercaptan, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(2-methylbutyronitrile) in the amounts described in Tables 2 to 3 as an initiator and a chain transfer agent were charged into a reaction vessel equipped with a stirring device, a heating and cooling device, a thermometer, and a nitrogen inlet tube. After nitrogen replacement (gas phase oxygen concentration: 100 ppm), the temperature was raised to 76 °C with stirring under a closed condition, and a polymerization reaction was carried out at this temperature for 6 hours.

[0318] Mineral oil [SP value: 8.3 (cal / cm 3 ) 1 / 2 , kinematic viscosity at 100 °C: 4.2 mm 2 / s, viscosity index: 122] 43 parts by weight was added, and after raising the temperature to 120 to 130 °C, unreacted monomers and ethyl acetate were removed at this temperature under reduced pressure (0.027 to 0.040 MPa) for 2 hours to obtain the antiwear agents (A-1) to (A-25) of the present invention containing 70% by weight of the copolymer and the antiwear agents (B-1) to (B-4) for comparison.

[0319]

[0320]

[0321]

[0322]

[0323]

[0324]

[0325] The various monomers described in Tables 2 to 3 are as follows.

[0326] (b-1): 2-Hydroxyethyl acrylate

[0327] (b-2): 2-Hydroxyethyl methacrylate

[0328] (b-3): 2-Hydroxy-2-methylpropyl methacrylate

[0329] (c-1): Methacrylated product of Neodol 23 (manufactured by Shell Chemical Company, a mixture of linear or branched alkyl alcohols with 12 to 13 carbon atoms (weight ratio = linear C12: branched C12: linear C13: branched C13 = 40:10:40:10))

[0330] (c-2): n-Hexadecyl methacrylate

[0331] (c-3): n-Octadecyl methacrylate

[0332] (c-4): 2-Decyltetradecyl methacrylate

[0333] (c-5): 2-Dodecylhexadecyl methacrylate

[0334] (c-6): 2-Tetradecyloctadecyl methacrylate

[0335] (c-7): n-Dodecyl acrylate

[0336] (c-8): n-Octadecyl acrylate

[0337] (c-9): Polybutadiene macromonomer (esterified product of Kuraray's L-1203 [1,2-adduct / 1,4-adduct = 45 / 55] with methacrylic acid, Mn = 6960)

[0338] (c-10): Polybutadiene macromonomer (esterified product of Kuraray's L-3203 [1,2-adduct / 1,4-adduct = 65 / 35] with methacrylic acid, Mn = 6960)

[0339] (d-1): Methyl methacrylate

[0340] (d-2): n-Butyl methacrylate

[0341] (e-1): 2-(Dimethylamino)ethyl methacrylate

[0342] <Mw of copolymer>

[0343] Under the conditions described in <Measurement conditions of Mw of copolymer (A)>, the Mw (weight average molecular weight) of the copolymer contained in the antiwear agents of Examples 1 to 25 and Comparative Examples 1 to 4 was measured.

[0344] <SP value of copolymer>

[0345] Based on the weight fractions of the respective constituent monomers at the time of feeding, the SP value of the copolymer was calculated.

[0346] <Total weight ratio of monomers (a) and (b)>

[0347] Based on the blending weights of monomers (a-1) to (a-10) and monomers (b-1) to (b-3), the total weight ratio of monomers (a) and monomer (b) in the monomers constituting copolymer (A) was calculated.

[0348] <Weight ratio of monomer (b) to monomer (a) (b / a)>

[0349] Based on the blending weights of monomers (a-1) to (a-10) and monomers (b-1) to (b-3), the weight ratio of monomer (b) to monomer (a) in the monomers constituting copolymer (A) was calculated.

[0350] <Examples 26 to 50, Comparative Examples 5 to 8>

[0351] The obtained antiwear agents (A-1) to (A-25) and comparative antiwear agents (B-1) to (B-4) were added to the following base oil I in an amount of 2% by weight based on the weight of the base oil (the addition amount is converted to solids), that is, the content of copolymer (A) in the lubricating oil composition was 2% by weight, to obtain lubricating oil compositions (V-1) to (V-25), (W-1) to (W-4).

[0352] 15 parts by weight of a package additive (Infineum T4641) was added to 85 parts by weight of base oil I (mineral oil, SP value: 8.3, kinematic viscosity at 100 °C: 2.4 mm 2 / s, viscosity index: 96).

[0353] <Added kinematic viscosity>

[0354] The kinematic viscosity at 100 °C and the kinematic viscosity at 40 °C of the lubricating oil compositions (V-1) to (V-25), (W-1) to (W-4) were measured by the method described in JIS-K2283 (2000), and the results were shown as the added kinematic viscosity (mm 2 / s) in Tables 2 and 3.

[0355] <Viscosity Index>

[0356] The viscosity index of the lubricating oil compositions (V-1) to (V-25), (W-1) to (W-4) was measured by the method described in JIS-K2283 (2000), and the results were shown as the viscosity index in Tables 2 and 3.

[0357] The wear evaluation of the lubricating oil compositions (V-1) to (V-25), (W-1) to (W-4) was measured by the following method. The maximum non-seizure load (N) measured by the following method was shown in Tables 2 and 3.

[0358] <Wear Evaluation>

[0359] Except that the test conditions were as described below, the test was carried out in accordance with ASTM D 2783. Specifically, for each lubricating oil composition, a high-speed four-ball tester was used, a load of 500 N was applied and it was rotated for 10 seconds to confirm the presence or absence of seizure. If there was no seizure, the load was increased by 10 N and the next test was carried out, and the load immediately before seizure occurred was measured as the maximum non-seizure load (N). The larger the value, the less likely seizure occurred and the more excellent the anti-wear effect was.

[0360] <Measurement Conditions>

[0361] Equipment: KRL & four-ball tester of SPACE CREATION

[0362] Ball: Steel ball for four-ball bearing, Size: 1 / 2

[0363] Speed: 1760 rpm

[0364] Temperature: 25 °C

[0365] Test time for one time: 10 seconds

[0366] Test start load: 500 N

[0367] Load increase interval: 10 N

[0368] From the results in the table, it can be seen that the lubricating oil compositions containing the anti-wear agent of the present invention (Examples 26 to 50) have higher anti-wear properties than the lubricating oil compositions of Comparative Examples 5 to 8.

[0369] Industrial Applicability

[0370] The lubricating oil composition containing the anti-wear agent of the present invention is suitable as drive train lubricating oil (such as MTF, differential gear oil, ATF, and belt-type CVTF, etc.), hydraulic oil (such as mechanical hydraulic oil, power steering oil, and shock absorber oil, etc.), engine oil (such as for gasoline engines and diesel engines, etc.), and traction oil.

Claims

1. An antiwear agent, which is an antiwear agent of a copolymer (A) containing monomer (a) represented by the following general formula (1) and monomer (b) represented by the following general formula (2) as essential constituent monomers, where, The weight ratio b / a of the monomer (b) constituting the copolymer (A) to the monomer (a) is 0.0005 to 0.12, [Chemical formula 1] In general formula (1), A 1 is a polymerizable group; -X 1 -, -X 2 -, and -X 3 - are each independently a group represented by -O- or -NH-; R 1 is an alkylene group having 1 to 4 carbon atoms; R 2 is an alkylene group having 2 to 20 carbon atoms; R 3 is a hydrogen atom, a linear or branched alkyl group having 1 to 44 carbon atoms, a phenyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, an acyl group having a linear or branched alkyl group having 1 to 44 carbon atoms, or a benzoyl group having a linear or branched alkyl group having 1 to 44 carbon atoms; p is an integer of 1 to 100, and when p is 2 or more, a plurality of R 2 and X 3 are each the same or different, [Chemical formula 2] In general formula (2), R 4 is a hydrogen atom or a methyl group; -X 4 - is a group represented by -O- or -NH-; R 5 is an alkylene group having 1 to 4 carbon atoms; -X 5 - is a group represented by -O- or -NH-.

2. The anti-wear agent according to claim 1, wherein, The copolymer (A) is a copolymer containing a monomer (c) represented by the following general formula (3) as a constituent monomer, [Chemical formula 3] In general formula (3), R 6 is a hydrogen atom or a methyl group; -X 6 - is a group represented by -O-, -O(AO) m - or -NH-, A is an alkylene group having 2 to 4 carbon atoms, m is an integer of 1 to 10, and when m is 2 or more, the plurality of As present are the same or different; R 7 is a linear or branched alkyl group having 5 to 700 carbon atoms.

3. The anti-wear agent according to claim 1, wherein, The weight-average molecular weight of the copolymer (A) is 5,000 to 500,000.

4. A lubricating oil composition comprising the antiwear agent according to any one of claims 1 to 3 and a base oil.

5. The lubricating oil composition according to claim 4, wherein The kinematic viscosity of the base oil at 100 °C is 1 mm 2 / s to 4 mm 2 / s.

6. The lubricating oil composition according to claim 4, wherein It further contains at least one selected from the group consisting of a viscosity index improver, a detergent, a dispersant, an antioxidant, an oiliness improver, a metal-based friction and wear modifier, an extreme pressure agent, an antifoaming agent, an anti-emulsifier, a corrosion inhibitor, and a pour point depressant.

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