Friction modifiers and lubricating oil compositions

Abstract

The present invention provides a friction modifier with excellent friction reduction effect, and a lubricating oil composition containing the friction modifier. [Solution] A friction modifier comprising a copolymer (A) whose essential constituent monomers are monomer (a) represented by general formula (1), monomer (b) represented by general formula (2), and monomer (c) represented by general formula (3), wherein the average value of p per mole of monomer (a) in monomer (a) constituting the copolymer (A) is 1 to 4. The proportion of monomer (c) is preferably 1 to 30% by weight based on the total weight of the monomers constituting the copolymer (A).

Description

[Technical Field]

[0001] The present invention relates to friction modifiers and lubricating oil compositions. [Background technology]

[0002] In recent years, in order to improve fuel efficiency, there has been a demand for improved power transmission efficiency and smaller size and lighter weight in automotive transmissions. As a result, transmission mechanisms have evolved from manual transmissions to automatic transmissions, and more recently, continuously variable transmissions (CVTs) are being installed in some vehicles. Meanwhile, electric vehicles equipped with lead-acid batteries, nickel-metal hydride batteries, lithium-ion batteries, fuel cells, etc., and fitted with electric motors, or hybrid vehicles that use these batteries in combination with internal combustion engines, have been developed, and in these vehicles, transmission oil and electric motor oil have been used separately.

[0003] Recently, in electric vehicles and hybrid vehicles, there has been a growing demand for the standardization of these oils and for miniaturization and weight reduction by packaging the transmission and electric motor. As a result, there is a need for a new oil that possesses not only the wear-preventive properties of manual transmission oil, automatic transmission oil, or continuously variable transmission oil, but also the insulating properties and copper compatibility of electric motor oil.

[0004] Friction modifiers are used to meet requirements such as wear prevention and seizure prevention, and generally, phosphate esters, zinc dithiophosphate, and organic sulfur compounds are added to mineral oil-based or synthetic base oils. However, transmission oils containing these friction modifiers have a corrosive effect on copper and also have insufficient insulation properties, so when used as electric motor oil, problems such as damage to copper wires and short circuits in electric motors can occur. Therefore, in electric vehicles or hybrid vehicles, there is a need for friction modifiers that can achieve both copper compatibility, insulation, and wear prevention.

[0005] Examples of friction modifiers that do not impair copper compatibility and insulation include polymer-type friction modifiers that do not contain sulfur or phosphorus as constituent elements. Specifically, known examples include copolymers composed of α-olefin and fumarate ester (Patent Document 1), acrylic acid ester copolymers having hydroxyl groups (Patent Document 2), polyesters having hydrophilic polymer units and polyolefin units (Patent Document 3), and methacrylic acid ester copolymers having a block structure composed of polar segment units and hydrophobic segment units (Patent Document 4). However, the above polymer friction modifiers have the problem that their friction reduction effect is not sufficient. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 3730660 [Patent Document 2] Patent No. 5822706 [Patent Document 3] Patent No. 5684832 [Patent Document 4] Japanese Patent Publication No. 4686444 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a friction modifier with excellent friction reduction effect and a lubricating oil composition containing the friction modifier. [Means for solving the problem]

[0008] The inventors of this invention arrived at this present invention as a result of diligent research to solve the above problems. In other words, the present invention is as follows. [1] A friction modifier comprising a copolymer (A) having monomer (a) represented by the following general formula (1), monomer (b) represented by the following general formula (2), and monomer (c) represented by the following general formula (3) as essential constituent monomers, A friction modifier in which, in monomer (a) among the monomers constituting the copolymer (A), the average value of p per 1 mol of monomer (a) is 1 to 4.

[0009]

Chemical formula

[0010] [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; p is a number from 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.]

[0011]

Chemical formula

[0012] [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 a linear or branched alkyl group having 1 to 44 carbon atoms.]

[0013]

Chemical formula

[0014] [In General Formula (3), R 6 is a hydrogen atom or a methyl group; A 2 O is an alkyleneoxy group having 1 to 4 carbon atoms, and a plurality of A 2 O may be the same or different from each other; q is a number from 2 to 1; R 7 is an alkyl group having carbon atoms.] [2] The friction modifier according to [1], wherein the proportion of monomer (c) in the monomers constituting the copolymer (A) is 1 to 30% by weight, based on the total weight of the monomers constituting the copolymer (A). A lubricating oil composition comprising the friction modifier and base oil described in [3] [1] or [2]. [4] The kinematic viscosity of the base oil at 100°C is 1 to 4 mm 2 The lubricating oil composition described in [3] is / s. [5] The lubricating oil composition according to [3] or [4] further comprising at least one selected from the group consisting of viscosity index improvers, detergents, dispersants, antioxidants, oiliness improvers, metallic friction and wear modifiers, extreme pressure agents, defoamers, anti-emulsifiers, corrosion inhibitors, and pour point depressants. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a friction modifier with excellent friction reduction effect, and a lubricating oil composition containing the friction modifier. [Modes for carrying out the invention]

[0016] <Friction modifier> The friction modifier of the present invention comprises a copolymer (A) whose essential constituent monomers are monomer (a) represented by the following general formula (1), monomer (b) represented by the following general formula (2), and monomer (c) represented by the following general formula (3). In the friction modifier of the present invention, the average value of p per mole of monomer (a) in monomer (a) constituting copolymer (A) is 1 to 4.

[0017] [ka]

[0018] [In general formula (1), A 1 is a polymerizable group; -X 1 -, -X 2 - and -X 3 - represents a group that is independently represented as -O- or -NH-; R 1 R is an alkylene group having 1 to 4 carbon atoms; 2R is an alkylene group having 2 to 20 carbon atoms; 3 R is a hydrogen atom; p is a number from 1 to 100, and if p is 2 or greater, there are multiple R 2 and X 3 These may be the same or different.

[0019] [ka]

[0020] [In general formula (2), R 4 is a hydrogen atom or a methyl group; -X 4 - represents a group represented by -O- or -NH-; R 5 [It is a linear or branched alkyl group having 1 to 44 carbon atoms.]

[0021] [ka]

[0022] [In general formula (3), R 6 is a hydrogen atom or a methyl group; A 2 O is an alkylene oxy group with 1 to 4 carbon atoms, and there are multiple A 2 O can be the same or different; q is a number between 2 and 100; R 7 [This refers to an alkyl group with 1 to 4 carbon atoms.]

[0023] <Copolymer (A)> In the present invention, copolymer (A) includes copolymer (A) whose essential constituent monomers are monomer (a) represented by general formula (1), monomer (b) represented by general formula (2), and monomer (c) represented by general formula (3).

[0024] In the present invention, copolymer (A) contains monomer (a) represented by the general formula (1) as an essential constituent monomer. In the present invention, the average value of p per mole of monomer (a) in monomer (a) constituting copolymer (A) is 1 to 4.

[0025] A in general formula (1) 1 This is a monovalent polymerizable group. A polymerizable group is a functional group that can undergo polymerization reactions, and specifically, radical polymerizable groups or cationic polymerizable groups are examples. Specific examples of polymerizable groups include vinyl groups and (meth)acryloyl groups. A 1 From the viewpoint of friction reduction effect, vinyl groups and (meth)acryloyl groups are preferred, and (meth)acryloyl groups are more preferred. In this invention, "(meth)acryloyl" means "acryloyl and / or methacryloyl," and "(meth)acrylate" means "acrylate and / or methacrylate."

[0026] -X in general formula (1) 1 -, -X 2 - and -X 3 Each of the hyphens represents a group that can be independently represented as either -O- or -NH-. -X 1 -, -X 2 - and -X 3 -From the viewpoint of friction reduction effect, -O- is preferred.

[0027] R in general formula (1) 1 This is an alkylene group having 1 to 4 carbon atoms. Examples of alkylene groups having 1 to 4 carbon atoms include methylene groups, ethylene groups, 1,2- or 1,3-propylene groups, and 1,2-, 1,3- or 1,4-butylene groups. Of these, from the viewpoint of friction reduction effect, ethylene groups and 1,2- or 1,3-propylene groups are preferred, and ethylene groups are more preferred.

[0028] R in general formula (1) 2This represents an alkylene group having 2 to 20 carbon atoms. Specifically, alkylene groups having 2 to 20 carbon atoms include: ethylene group, isopropylene group, 1,2- or 1,3-propylene group, isobutylene group, 1,2-, 1,3- or 1,4-butylene group, isopentylene group, 1,2-, 1,3-, 1,4- or 1,5-pentylene group, isohexylene group, 1,2-, 1,3-, 1,4-, 1,5- or 1,6-hexylene group, isoheptylene group, 1,2-, 1,3-, 1,4-, 1,5-, 1,6- or 1,7-heptylene group, isooctylene, 1,8-octylene group, isononylene group, 1,9-nonylene group, and Examples include sodecylene group, 1,10-decylene group, isoundecylene group, 1,11-undecylene group, isododecylene group, 1,12-dodecylene group, isotridecylene group, 1,13-tridecylene group, isotetradecylene group, 1,14-tetradecylene group, isopentadecylene group, 1,15-pentadeciylene group, isohexadecylene group, 1,16-hexadecylene group, isoheptadeciylene group, 1,17-heptadeciylene group, isooctadecylene group, 1,18-isooctadecylene group, isononadecylene group, 1,19-isonononadecylene group, isoeicosilene group, 1,20-eicosilene group, and the like. R 2 From the viewpoint of friction reduction effect, storage stability and high-temperature stability, the alkylene group is preferably a C2-C17 alkylene group, more preferably a C2-C15 alkylene group, particularly preferably a C2-C13 alkylene group, and most preferably a C2-C10 alkylene group.

[0029] In general formula (1), p represents the number of moles added to the lactam and / or lactone, as described below. If p in general formula (1) is 2 or greater, there are multiple R 2 and X 3 These may be the same or different.

[0030] In monomer (a) within the monomers constituting copolymer (A), the average value of p per mole of monomer (a) (average number of moles added, hereinafter also referred to as the molar average value of p) is 1 to 4, more preferably 1.5 to 3.5, and particularly preferably 2.0 to 3.5, from the viewpoint of friction reduction effect. If the average value of p per mole of monomer (a) exceeds 4, the friction reduction effect may deteriorate. The reason why the friction-reducing effect of friction modifiers deteriorates is not entirely clear, but it is presumed that when the average value of p per mole of monomer (a) exceeds 4, the number of ester groups and / or amide groups in copolymer (A) increases, making it easier for molecules to aggregate and precipitate during long-term storage. When precipitation becomes more likely, it becomes difficult to use a large amount of monomer (a) as a constituent monomer of copolymer (A), thus reducing the friction-reducing effect.

[0031] The monomer constituting the copolymer (A) may be one type of monomer (a) or two or more types of monomer (a). If the copolymer (A) consists of two or more monomers (a), the weighted average of the p values ​​of each monomer (a) based on the mole fraction of each monomer in monomer (a) is the molar mean value of p in general formula (1). The mole fractions 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 thermal decomposition GC / MS. Alternatively, when measuring the p of monomer (a) before it is incorporated into copolymer (A), the p of monomer (a) 1 The molar mean of p can be measured from the spectrum obtained by 1H-NMR (nuclear magnetic resonance) spectroscopy. For example, if the "lactam and / or lactone" is ε-caprolactone, the molar mean 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 of the carbonyl carbon derived from ε-caprolactone) by the integral value of the peak around 6.4 ppm or 6.1 ppm (one of the hydrogen atoms bonded to the unsaturated double bond of the acryloyl group or methacryloyl group). The γ hydrogen of the carbonyl carbon derived from ε-caprolactone is the structural formula derived from ε-caprolactone (-CO-CH2-CH2-C * This refers to the hydrogen atom bonded to the carbon atom marked with an asterisk (*) in the H2-CH2-CH2-O- (H2-CH2-CH2-O-) sequence. The hydrogen atom bonded to the unsaturated double bond of the acryloyl group is H2C, which is the structural formula of the acryloyl group. * =CH-CO- refers to the hydrogen atom bonded to the carbon atom marked with an asterisk. The hydrogen atom bonded to the unsaturated double bond of the methacryloyl group is H2C, which is the structural formula of the methacryloyl group. * =This refers to the hydrogen atom bonded to the carbon atom marked with an asterisk in C(CH3)-CO-. Specifically, the molar mean of p can be calculated using the following formula. (A in general formula (1) 1 (If it is an acryloyl group) The molar mean of p = (integral value of the peak of the γ hydrogen of the carbonyl carbon derived from ε-caprolactone / 2) / (integral value of one of the peaks of hydrogen atoms bonded to the unsaturated double bond of the acryloyl group) (A in general formula (1) 1 (If it is a methacryloyl group) The molar mean of p = (integral value of the peak of the γ hydrogen of the carbonyl carbon derived from ε-caprolactone / 2) / (integral value of one of the peaks of hydrogen atoms bonded to the unsaturated double bond of the methacryloyl group)

[0032] R in general formula (1) 3 This represents a hydrogen atom.

[0033] From the viewpoint of friction reduction effect, preferred monomers (a) include 1-4 mole lactone adducts of hydroxyalkyl (meth)acryloyl monomers, 1-4 mole lactam adducts of hydroxyalkyl (meth)acryloyl monomers, 1-4 mole lactone adducts of aminoalkyl (meth)acryloyl monomers, and 1-4 mole lactam adducts of aminoalkyl (meth)acryloyl monomers, and more preferably 1-4 mole lactone adducts of hydroxyalkyl (meth)acryloyl monomers. In the examples described above, the number of moles of lactone or lactam added refers to the average number of moles added.

[0034] Examples of hydroxyalkyl(meth)acryloyl monomers include hydroxyalkyl(meth)acrylates {hydroxymethyl(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, hydroxybutyl(meth)acrylate, etc.} and hydroxyalkyl(meth)acrylamides {hydroxymethyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, hydroxypropyl(meth)acrylamide, hydroxybutyl(meth)acrylamide, etc.}.

[0035] Examples of aminoalkyl (meth)acryloyl monomers include aminoalkyl (meth)acrylates {aminomethyl (meth)acrylate, aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, aminobutyl (meth)acrylate, etc.} and aminoalkyl (meth)acrylamides {aminomethyl (meth)acrylamide, aminoethyl (meth)acrylamide, aminopropyl (meth)acrylamide, aminobutyl (meth)acrylamide, etc.}.

[0036] Lactones include those with 3 to 21 carbon atoms, such as β-propiolactone, γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

[0037] Lactams include those with 3 to 21 carbon atoms, such as β-lactams, γ-lactams, and δ-lactams.

[0038] Lactone adducts of hydroxyalkyl (meth)acryloyl monomers or aminoalkyl (meth)acryloyl monomers (1-4 molars) can be obtained, for example, by ring-opening addition of a lactone to a hydroxyalkyl (meth)acryloyl monomer or aminoalkyl (meth)acryloyl monomer. The reaction temperature for the ring-opening addition reaction is preferably 80 to 150°C, and more preferably 100 to 140°C, from the viewpoint of reaction time. The reaction time is preferably 2 to 24 hours, and more preferably 3 to 10 hours. The reaction may be carried out in the presence of a catalyst. Any known catalyst can be used as the catalyst for the above reaction, including p-toluenesulfonic acid, tetrapropyl titanate, and stannous octanoate. The amount of catalyst used is preferably 0.01 to 5% by mass, and more preferably 0.03 to 0.5% by mass, relative to the amount of reaction product. After the ring-opening addition reaction is complete, it is desirable to treat the catalyst by methods such as adsorption and filtration using an adsorbent, or neutralization to deactivate the catalyst.

[0039] Lactam adducts of hydroxyalkyl (meth)acryloyl monomers or aminoalkyl (meth)acryloyl monomers (1-4 molars) can be obtained, for example, by ring-opening addition of a lactam to a hydroxyalkyl (meth)acryloyl monomer or aminoalkyl (meth)acryloyl monomer. The reaction temperature for the ring-opening addition reaction of lactams is preferably 80 to 150°C, and more preferably 100 to 140°C, from the viewpoint of reaction time. The reaction time is preferably 2 to 24 hours, and more preferably 3 to 10 hours. The reaction may be carried out in the presence of a catalyst. Any known catalyst can be used as the catalyst for the above reaction, such as tetrapropyl titanate or stannous octanoate. The amount of catalyst used is preferably 0.01 to 5% by mass, and more preferably 0.03 to 0.5% by mass, relative to the amount of reaction product. After the ring-opening addition reaction is complete, it is desirable to treat the catalyst by methods such as adsorption and filtration using an adsorbent, or neutralization to deactivate the catalyst.

[0040] From the viewpoint of friction reduction, monomer (a) is preferably a 1-4 molar adduct of lactone from hydroxyalkyl (hydroxyalkyl group with 1-4 carbon atoms) (meth)acrylate, more preferably a 1-4 molar adduct of lactone from hydroxyalkyl (hydroxyalkyl group with 2-4 carbon atoms) (meth)acrylate, even more preferably a 1-4 molar adduct of ε-caprolactone from hydroxyalkyl (hydroxyalkyl group with 2-3 carbon atoms) (meth)acrylate, particularly preferably a 1-4 molar adduct of ε-caprolactone from hydroxyethyl (meth)acrylate, and most preferably a 1-3 molar adduct of ε-caprolactone from hydroxyethyl (meth)acrylate.

[0041] The constituent units derived from monomer (a) (structures formed by the reaction of polymerizable groups (such as vinyl groups) of monomer (a) to form single bonds) are preferably those that have a specific solubility parameter (sometimes abbreviated as SP value below) from the viewpoint of solubility in lubricating oil base oil. The SP value of the constituent unit derived from monomer (a) is preferably 10.0 to 12.5 (cal / cm³). 3 ) 1 / 2 And more preferably 10.3 to 12.3 (cal / cm²). 3 ) 1 / 2 And, particularly preferably, 10.5 to 12.0 (cal / cm²). 3 ) 1 / 2 That is the case.

[0042] In this invention, the SP value refers to the value calculated using formula (28) on page 153 of the Fedors method (Polymer Engineering and Science, February, 1974, Vol. 14, No. 2, pp. 147-154), using the numerical values ​​(heat of vaporization and molar volume of atoms or functional groups at 25°C) listed on page 152 (Table 5). Specifically, it refers to the Δe parameter of the Fedors method, as listed in Table 1 below. i and v i The values ​​can be used to calculate the following formula by applying the values ​​corresponding to the types of atoms and atomic groups within the molecular structure. SP value = (ΣΔei / Σv i ) 1 / 2

[0043] [Table 1]

[0044] When the copolymer (A) uses two or more monomers (a) as monomers, it is preferable that the SP value of monomer (a) is calculated by determining the SP value of each of the multiple monomers (a) constituting the copolymer (A) using the method described above, and that the arithmetic mean of the SP values ​​of each monomer (a) based on their weight fractions is within the range described above.

[0045] In the present invention, copolymer (A) contains monomer (b) represented by the general formula (2) as an essential constituent monomer. One type of monomer (b) may be used as the monomer constituting copolymer (A), or two or more types may be used.

[0046] R in general formula (2) 4 This is either a hydrogen atom or a methyl group, and of these, a methyl group is preferred from the viewpoint of friction reduction and viscosity index improvement effect.

[0047] -X in general formula (2) 4 - is a group represented by -O- or NH-, and of these, -O- is preferred from the viewpoint of friction reduction.

[0048] R in general formula (2) 5These are linear or branched alkyl groups having 1 to 44 carbon atoms, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, n-decyl group, isodecyl group, n-undecyl group, isoundecyl group, n-dodecyl group, isododecyl group, n-tridecyl group, isotridecyl group, n-tetradecyl group, 2-ethyldodecyl group, n-pentadecyl group, 2-methyltetradecyl group, n-hexadecyl group, isohexadecyl group, n-heptadecyl group, isoheptadecyl group, 2-ethylpentadecyl group, 2-octylnonyl group, 2-(3-methylhexyl)-7-methylnonyl group, n-octadecyl group, isooctadecyl group, 2-(3-methylhexyl)-7-methylnonyl group, n-octadecyl group, isooctadecyl group, 2-(3-methylhexyl)-7-methylnonyl group, n-octadecyl group, isooctadecyl group, 2-(3-methylhexyl)-7-methylnonyl group Examples include xylundecyl group, 2-ethylheptadecyl group, 1-hexyltridecyl group, n-icosyl group, 2-octylundecyl group, isoicosyl group, 1-undecyldodecyl group, 1-octylpentadecyl group, 2-decyltridecyl group, n-tetraicosyl group, 2-decyltetradecyl group, 2-dodecylpentadecyl group, 2-heptylicosyl group, 2-dodecylhexadecyl group, n-triacontyl group, 2-tetradecyloctadecyl group, n-hexatriacontyl group, n-tetracontyl group, 2-ethyltetracontyl group, and olefins [e.g., propylene oligomers (2-14 units), ethylene / propylene oligomers (2-20 units), and isobutene oligomers (2-10 units), etc.].

[0049] R 5 Of these, from the viewpoint of base oil solubility, linear or branched alkyl groups having 1 to 34 carbon atoms are preferred, more preferably linear or branched alkyl groups having 12 to 32 carbon atoms are preferred, particularly preferably linear or branched alkyl groups having 16 to 32 carbon atoms are preferred, and most preferably linear alkyl groups having 16 to 22 carbon atoms and branched alkyl groups having 18 to 32 carbon atoms are preferred.

[0050] Examples of monomers (b) 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, pentyl (meth)acrylate, hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, and 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-hex Tadecyl (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-icosyl (meth)acrylate, 2-octylundecyl (meth)acrylate )Acrylate, isoicosyl(meth)acrylate, 1-undecyldodecyl(meth)acrylate, 1-octylpentadecyl(meth)acrylate, 2-decyltridecyl(meth)acrylate, n-tetraicosyl(meth)acrylate, 2-decyltetradecyl(meth)acrylate, 2-dodecylpentadecyl(meth)acrylate, 2-heptylicosyl(meth)acrylate, 2-dodecylhexadecyl(meth)acrylate, n-triacontyl(meth)acrylate, 2-tetradecyloctadecyl(meth)acrylate,Examples include alkyl(meth)acrylates such as n-hexa-triacontyl(meth)acrylate, n-tetracontyl(meth)acrylate, and 2-ethyltetracontyl(meth)acrylate; and N-alkyl(meth)acrylamides such as N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, and N-butyl(meth)acrylamide.

[0051] The monomer (b) is preferably at least one selected from the group consisting of methyl (meth)acrylate and butyl (meth)acrylate, n-dodecyl (meth)acrylate (also called n-dodecyl (meth)acrylic acid), (meth)acrylic acid esters of linear or branched alkyl alcohols having 12 to 13 carbon atoms, n-hexadecyl (meth)acrylate (also called n-hexadecyl (meth)acrylic acid), n-octadecyl (meth)acrylate (also called n-octadecyl (meth)acrylic acid), 2-decyltetradecyl (meth)acrylate (also called 2-decyltetradecyl (meth)acrylic acid), 2-dodecylhexadecyl (meth)acrylate (also called 2-dodecylhexadecyl (meth)acrylic acid), and 2-tetradecyloctadecyl (meth)acrylate (also called 2-tetradecyloctadecyl (meth)acrylic acid).

[0052] The monomer (b) is a (meth)acrylate [R] having a linear or branched alkyl group with 1 to 34 carbon atoms. 5 It is preferable to use at least one (meth)acrylate having a linear or branched alkyl group with 1 to 34 carbon atoms, and a (meth)acrylate having an alkyl group with 10 to 34 carbon atoms [R 5 [meth)acrylates having linear or branched alkyl groups with 10 to 34 carbon atoms and (meth)acrylates having alkyl groups with 1 to 4 carbon atoms [R 5 It is more preferable to use two or more selected from the group consisting of (meth)acrylates of linear or branched alkyl groups having 1 to 4 carbon atoms.

[0053] In the present invention, copolymer (A) contains monomer (c) represented by the general formula (3) as an essential constituent monomer. One type of monomer (c) may be used as the monomer constituting copolymer (A), or two or more types may be used.

[0054] In general formula (3), R 6 R is a hydrogen atom or a methyl group. 6 A methyl group is preferred as the group.

[0055] In general formula (3), A 2 O is an alkylene oxy group having 1 to 4 carbon atoms. Examples of alkylene oxy groups having 1 to 4 carbon atoms include methylene oxy group, ethylene oxy group, 1,2- or 1,3-propylene oxy group, and 1,2-, 1,3- or 1,4-butylene oxy group. Of these, from the viewpoint of friction reduction effect, ethylene oxy group and 1,2- or 1,3-propylene oxy group are preferred, and ethylene oxy group is more preferred. There are multiple A 2 The oxygen atoms may be the same or different, but it is preferable that they be the same, and more preferably that they consist only of ethyleneoxy groups.

[0056] In general formula (3), q is a number between 2 and 100. There are multiple A 2 O may be the same or different in each case. From the viewpoint of friction reduction effect, q is preferably between 2 and 90.

[0057] R in general formula (3) 7 The C1-C4 alkyl group is an alkyl group having 1 to 4 carbon atoms. Examples of C1-C4 alkyl groups include methyl, ethyl, propyl, and butyl groups, which may be linear or branched. Of these, the methyl group is preferred from the viewpoint of friction reduction effect.

[0058] As the monomer (c) represented by the general formula (3), commercially available products may be used. Examples of commercially available products include "Blemmer (registered trademark) PME series" and "Blemmer (registered trademark) AME series" manufactured by NOF Corporation. Specifically, "Blemmer PME-100 (methoxypolyethylene glycol methacrylate, R in the general formula (3) 6 is a methyl group, A 2 O is an ethyleneoxy group, q ≈ 2, R 7 is a methyl group)", "Blemmer PME-200 (methoxypolyethylene glycol methacrylate, R in the general formula (3) 6 is a methyl group, A 2 O is an ethyleneoxy group, q ≈ 4, R 7 is a methyl group), Blemmer PME-400 (methoxypolyethylene glycol methacrylate, R in the general formula (3) 6 is a methyl group, A 2 O is an ethyleneoxy group, q ≈ 9, R 7 is a methyl group), Blemmer PME-1000 (methoxypolyethylene glycol methacrylate, R in the general formula (3) 6 is a methyl group, A 2 O is an ethyleneoxy group, q ≈ 23, R 7 is a methyl group), Blemmer PME-4000 (methoxypolyethylene glycol methacrylate, R in the general formula (3) 6 is a methyl group, A 2 O is an ethyleneoxy group, q ≈ 90, R 7 is a methyl group)", "Blemmer AME-400 (methoxypolyethylene glycol acrylate, R in the general formula (3) 6 is a hydrogen atom, A 2 O is an ethyleneoxy group, q ≈ 9, R 7 is a methyl group), etc. can be mentioned.

[0059] The monomers constituting the copolymer (A) may contain monomer (e) as a constituent monomer in addition to the above essential monomers [monomer (a), monomer (b) and monomer (c)]. Examples of monomer (e) include nitrogen atom-containing monomers other than monomer (a) and monomer (b) (e1), hydroxyl group-containing monomers other than monomer (a) (e2), and phosphorus atom-containing monomers (e3). These may be used individually or in combination of two or more.

[0060] Examples of nitrogen atom-containing monomers (e1) include the following monomers (e11) to (e14).

[0061] Examples of amide group-containing monomers (e11) include (meth)acrylamide, monoalkylaminoalkyl(meth)acrylamide [having an aminoalkyl group (2-6 carbon atoms) with one C1-4 alkyl group bonded to the nitrogen atom; for example, N-methylaminoethyl(meth)acrylamide, N-ethylaminoethyl(meth)acrylamide, N-isopropylamino-n-butyl(meth)acrylamide, and Nn- or isobutylamino-n-butyl(meth)acrylamide], and dialkylamino(meth)acrylamide [having two C1-4 alkyl groups bonded to the nitrogen atom; for example, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide]. Examples include lylamides and N,N-di-n-butyl(meth)acrylamide, dialkylaminoalkyl(meth)acrylamides [those having an aminoalkyl group (2-6 carbon atoms) in which two alkyl groups with 1-4 carbon atoms are bonded to a 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.], and N-vinyl carboxylic acid amides [N-vinylformamide, N-vinylacetamide, N-vinyl-n- or isopropionylamide, and N-vinylhydroxyacetamide, etc.], which have a nitrogen atom only in the amide group.

[0062] Examples of nitro group-containing monomers (e12) include 4-nitrostyrene.

[0063] Examples of primary to tertiary amino group-containing monomers (e13) include primary amino group-containing vinyl monomers {alkenylamines with 3 to 6 carbon atoms [(meth)allylamine and clotylamine, etc.], aminoalkyl (2 to 6 carbon atoms) (meth)acrylates [aminoethyl (meth)acrylate, etc.]}; secondary amino group-containing vinyl monomers {monoalkylaminoalkyl (meth)acrylates [those having an aminoalkyl group (2 to 6 carbon atoms) with one alkyl group of 1 to 6 carbon atoms bonded to the nitrogen atom; for example, t-butylaminoethyl (meth)acrylate and methylaminoethyl (meth)acrylate, etc.], dialkenylamines with 6 to 12 carbon atoms [di(meth)allylamine, etc.]}; tertiary amino group-containing vinyl monomers {dialkylaminoalkyl (meth)acrylate Examples include aminoalkyl groups (with 2 to 6 carbon atoms) in which two alkyl groups with 1 to 6 carbon atoms are bonded to a nitrogen atom; for example, N,N-dimethylaminoethyl (meth)acrylate and N,N-diethylaminoethyl (meth)acrylate, etc.), alicyclic (meth)acrylates having a nitrogen atom (for example, morpholinoethyl (meth)acrylate), aromatic vinyl monomers (for example, N,N-diphenylaminoethyl (meth)acrylamide, N,N-dimethylaminostyrene, 4-vinylpyridine, 2-vinylpyridine, N-vinylpyrrole, N-vinylpyrrolidone and N-vinylthiopyrrolidone, etc.), and their hydrochloride salts, sulfates, phosphates, or lower alkyl (1 to 8 carbon atoms) monocarboxylic acid (acetic acid and propionic acid, etc.) salts.

[0064] Examples of nitrile group-containing monomers (e14) include (meth)acrylonitrile.

[0065] Among the nitrogen atom-containing vinyl monomers (e1), preferred are amide group-containing monomers (e11) and primary to tertiary amino group-containing monomers (e13), and even more preferred are 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.

[0066] Examples of hydroxyl group-containing monomers (e2) include the following: Hydroxyl group-containing aromatic monomers (e.g., p-hydroxystyrene), hydroxyalkyl (C2-C6) (meth)acrylates [e.g., 2-hydroxyethyl (meth)acrylate, 2- or 3-hydroxypropyl (meth)acrylate and 2-hydroxy-2 methylpropyl (meth)acrylate], mono- or di-hydroxyalkyl (C1-C4) substituted (meth)acrylamides [e.g., N,N-dihydroxymethyl (meth)acrylamide, N,N-dihydroxypropyl (meth)acrylamide, N,N-di-2-hydroxybutyl (meth)acrylamide], vinyl alcohol, C3-C12 alkenols [(meth)allyl alcohol, Examples include: clotyl alcohol, isoclotyl alcohol, 1-octenol and 1-undecenol, etc.; alkene monools or alkene diols having 4 to 12 carbon atoms [1-buten-3-ol, 2-buten-1-ol and 2-buten-1,4-diol, etc.]; hydroxyalkyl (1 to 6 carbon atoms) alkenyl (3 to 10 carbon atoms) ethers (2-hydroxyethylpropenyl ether, etc.); and alkenyl (3 to 10 carbon atoms) ethers or (meth)acrylates of polyhydric (3 to 8 hydric) alcohols (glycerin, pentaerythritol, sorbitol, sorbitan, diglycerin, sugars and sucrose, etc.) [sucrose (meth)allyl ether, etc.].

[0067] Examples of phosphorus atom-containing monomers (e3) include the following monomers (e31) to (e32).

[0068] Examples of phosphate ester group-containing monomers (e31) include (meth)acryloyloxyalkyl (C2-C4) phosphate esters [(meth)acryloyloxyethyl phosphate and (meth)acryloyloxyisopropyl phosphate] and alkenyl phosphate esters [vinyl phosphate, allyl phosphate, propenyl phosphate, isopropenyl phosphate, butenyl phosphate, pentenyl phosphate, octenyl phosphate, decenyl phosphate and dodecenyl phosphate, etc.].

[0069] Examples of phosphono group-containing monomers (e32) include (meth)acryloyloxyalkyl (2-4 carbon atoms) phosphonic acids [such as (meth)acryloyloxyethylphosphonic acid] and alkenyl (2-12 carbon atoms) phosphonic acids [such as vinylphosphonic acid, allylphosphonic acid, and octenylphosphonic acid].

[0070] Among the phosphorus atom-containing monomers (e3), the most preferred is the phosphate ester group-containing monomer (e31), more preferably is the (meth)acryloyloxyalkyl (2-4 carbon atoms) phosphate ester, and particularly preferred is (meth)acryloyloxyethyl phosphate.

[0071] The monomers constituting copolymer (A) may include monomers other than the essential constituent monomers and monomer (e) mentioned above. These other monomers may be one or more monomers selected from the group consisting of alkoxyalkyl ether monomers (f), aliphatic hydrocarbon monomers (g), alicyclic hydrocarbon monomers (h), aromatic hydrocarbon monomers (i), vinyl esters, vinyl ethers and vinyl ketones (j), epoxy group-containing monomers (k), halogen-containing monomers (m), and esters of unsaturated polycarboxylic acids (n).

[0072] Examples of alkoxyalkyl ether monomers (f) include 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, and propoxymethyl (meth)acrylate. Examples include phosphates, 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. Among the monomers (f), preferred are methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and butoxyethyl (meth)acrylate.

[0073] Examples of aliphatic hydrocarbon monomers (g) include alkenes with 2 to 20 carbon atoms (ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, and octadecene, etc.) and alkadienes with 4 to 12 carbon atoms (butadiene, isoprene, 1,4-pentadiene, 1,6-heptadiene, and 1,7-octadiene, etc.).

[0074] Examples of alicyclic hydrocarbon monomers (h) include cyclohexene, (di)cyclopentadiene, pinene, limonene, vinylcyclohexene, and ethylidenebicycloheptene.

[0075] Examples of aromatic hydrocarbon monomers (i) include styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, 4-ethylstyrene, 4-isopropylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-cyclohexylstyrene, 4-benzylstyrene, indene, 4-clotylbenzene, and 2-vinylnaphthalene.

[0076] Examples of vinyl esters, vinyl ethers, and vinyl ketones (j) include vinyl esters of saturated fatty acids having 2 to 12 carbon atoms (vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl octanoate, etc.), alkyl, aryl, or alkoxyalkyl vinyl ethers having 1 to 12 carbon atoms (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, etc.), and alkyl or aryl vinyl ketones having 1 to 8 carbon atoms (methyl vinyl ketone, ethyl vinyl ketone, and phenyl vinyl ketone, etc.).

[0077] Examples of epoxy group-containing monomers (k) include glycidyl (meth)acrylate and glycidyl (meth)allyl ether.

[0078] Examples of halogen-containing monomers (m) include vinyl chloride, vinyl bromide, vinylidene chloride, (meth)allyl chloride, and halogenated styrenes (such as dichlorostyrene).

[0079] Examples of esters (n) of unsaturated polycarboxylic acids include alkyl, cycloalkyl, or aralkyl esters of unsaturated polycarboxylic acids [alkyl diesters of unsaturated dicarboxylic acids (maleic acid, fumaric acid, and itaconic acid, etc.) having 1 to 8 carbon atoms (dimethyl maleate, dimethyl fumarate, diethyl maleate, and dioctyl maleate)].

[0080] The weight percentage of monomer (a) in the monomers constituting copolymer (A) is preferably 10% by weight or more, more preferably 15% by weight or more, and even more preferably 20% by weight or more, based on the total weight of the monomers constituting copolymer (A), from the viewpoint of friction reduction effect. The weight percentage of monomer (a) is preferably 80% by weight or less, more preferably 75% by weight or less, based on the total weight of the monomers constituting copolymer (A).

[0081] From the viewpoint of base oil solubility, the weight percentage of monomer (b) in the monomers constituting copolymer (A) is preferably 30% by weight or more, more preferably 40% by weight or more, preferably 85% by weight or less, and more preferably 80% by weight or less, based on the total weight of the monomers constituting copolymer (A).

[0082] From the viewpoint of friction reduction and base oil solubility, the weight ratio of monomer (c) in the monomers constituting copolymer (A) is preferably 1% by weight or more, more preferably 5% by weight or more, preferably 30% by weight or less, and more preferably 25% by weight or less, based on the total weight of the monomers constituting copolymer (A).

[0083] From the viewpoint of friction reduction, the total weight percentage of essential monomers [monomer (a), monomer (b), and monomer (c)] in the monomers constituting copolymer (A) is preferably 80 to 100% by weight, and more preferably 90 to 100% by weight, based on the total weight of the monomers constituting copolymer (A).

[0084] The total weight ratio of monomers other than the essential monomers [monomers (e) to (k), monomers (m) to (n)] in the monomers constituting the copolymer (A) is preferably 20% by weight or less, more preferably 10% by weight or less, based on the total weight of the monomers constituting the copolymer (A) from the viewpoint of friction reduction properties.

[0085] The respective weight ratios of monomers (a) to (c), monomers (e) to (k), and monomers (m) to (n) in the copolymer (A) can be measured by methods such as pyrolysis GC / MS. Also, the weight ratio of each constituent monomer at the time of charging in the production of the copolymer (A) may be used as the respective weight ratios of monomers (a) to (c), monomers (e) to (k), and monomers (m) to (n) in the copolymer (A).

[0086] The SP value of the copolymer (A) is preferably 8.5 to 11.5 (cal / cm 3 ) 1 / 2 from the viewpoints of base oil solubility and viscosity index improvement effect, 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 and particularly preferably 9.2 to 10.2 (cal / cm 3 ) 1 / 2 .

[0087] The SP value of the copolymer (A) means a value obtained by calculating the SP values of the structural units (structures in which the polymerizable groups (vinyl groups, etc.) contained in each monomer constituting the copolymer (A) become single bonds by a polymerization reaction) derived from each monomer constituting the copolymer (A) using the above-described method for calculating the SP value, and performing a weighted average based on the weight fractions of each constituent monomer at the time of charging. For example, when the monomer is 2-dodecylhexadecyl methacrylate, the structural unit derived from the monomer has, as atomic groups, three CH3s, twenty-six CH2s, one CH, one C, and one CO2. The Δe i and v iUsing this method, the SP value of the constituent unit derived from 2-dodecylhexadecyl methacrylate is calculated to be 8.746 (cal / cm³). 3 ) 1 / 2 It can be seen that this is the case. ΣΔe i =1125×3+1180×26+820+350+4300=39525 Σv i = 33.5 × 3 + 16.1 × 26 - 1.0 - 19.2 + 18.0 = 516.9 δ = (39525 / 516.9) 1 / 2 = 8.746 (cal / cm 3 ) 1 / 2 Calculating in the same manner as above, the SP value of the constituent unit derived from 2-tetradecyloctadecyl methacrylate is 8.724 (cal / cm³). 3 ) 1 / 2 It can be seen that this is the case. When the polymer is a polymer of 50% by weight of 2-dodecylhexadecyl methacrylate and 50% by weight of 2-tetradecyloctadecyl methacrylate, the SP value of the polymer is calculated by taking the arithmetic mean based on the weight fraction of the SP values ​​of the constituent units derived from each monomer, as shown below. SP value of polymer = (8.746 × 50 + 8.724 × 50) / 100 = 8.735 The SP value of copolymer (A) can be set to a desired range by appropriately adjusting the monomers and their weight fractions used. Specifically, the SP value can be reduced by using a large amount of monomers with long alkyl groups, and increased by using a large amount of monomers with short alkyl groups.

[0088] The weight-average molecular weight (hereinafter abbreviated as Mw) of copolymer (A) is preferably 5000 or more, and more preferably 10000 or more, from the viewpoint of friction reduction. There is no particular upper limit to the Mw of copolymer (A), but it is preferably 1,000,000 or less, more preferably 700,000 or less, and even more preferably 500,000 or less.

[0089] Mw can be measured by gel permeation chromatography under the following conditions. <Measurement conditions for Mw of copolymer (A)> Device: "HLC-8320GPC" [Manufactured by Tosoh Corporation] Columns: 1 "Guardcolumn Super HZM-M" [manufactured by Tosoh Corporation], 3 "TSKgel Super HZM-M" [manufactured by Tosoh Corporation] Measurement temperature: 40℃ Sample solution: 0.25% by weight tetrahydrofuran solution Solution injection volume: 100μl Detection device: Refractive index detection G Reference material: Standard polystyrene (TSKstandard POLYSTYRENE) 12 samples (molecular weight: 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]

[0090] Copolymer (A) can be obtained by known manufacturing methods, specifically by solution polymerization of the monomer in a solvent in the presence of a polymerization catalyst. Examples of solvents include toluene, xylene, alkylbenzenes having 9 to 10 carbon atoms, methyl ethyl ketone, ethyl acetate, 2-propanol, and base oils described later. Polymerization catalysts include azo catalysts (such as azobisisobutyronitrile, azobis-2methylbutyronitrile, and azobisvaleronitrile), 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). Furthermore, known chain transfer agents (such as alkyl mercaptans with 2 to 20 carbon atoms) can be used as needed. The polymerization temperature is preferably 25 to 140°C, and more preferably 50 to 120°C. In addition to the solution polymerization described above, copolymer (A) can also be obtained by bulk polymerization, emulsion polymerization, or suspension polymerization. When copolymer (A) is a copolymer, the polymerization form may be either a random addition copolymer or an alternating copolymer, and it may also be either a graft copolymer or a block copolymer.

[0091] The friction modifier of the present invention may contain the copolymer (A), but may also contain a base oil from the viewpoint of handling (ease of addition to lubricating oil composition, etc.). Examples of base oils include mineral oils (solvent-refined oils, paraffin oils, high viscosity index oils containing isoparaffins, high viscosity index oils obtained by hydrocracking of isoparaffins, and naphthenic oils, etc.), synthetic lubricants [hydrocarbon-based synthetic lubricants (poly-α-olefin-based synthetic lubricants, etc.) and ester-based synthetic lubricants, etc.], and mixtures thereof. Of these, mineral oils are preferred from the viewpoint of insulating properties.

[0092] The content of copolymer (A) in the friction modifier is preferably 20 to 90% by weight, and more preferably 30 to 80% by weight, based on the weight of the friction modifier, from the viewpoint of handling (ease of addition to lubricating oil composition, etc.). The base oil content in the friction modifier is preferably 10 to 80% by weight, and more preferably 20 to 70% by weight, based on the weight of the friction modifier, from the viewpoint of handling (ease of addition to lubricating oil composition, etc.).

[0093] The friction modifier of the present invention has excellent friction reduction effects and is therefore suitably used in gear oil (differential oil and industrial gear oil, etc.), MTF, transmission oil [ATF and belt-CVTF, etc.], traction oil (toroidal-CVT F, etc.), shock absorber oil, power steering oil, hydraulic oil (hydraulic oil for construction machinery and industrial hydraulic oil, etc.), and engine oil, and is preferably used as a friction modifier for transmission oil, electric motor oil, and dual-purpose oil for transmissions and electric motors in electric vehicles or hybrid vehicles, and is particularly preferably used as a friction modifier for dual-purpose oil for transmissions and electric motors in electric vehicles or hybrid vehicles.

[0094] <Lubricating oil composition> The lubricating oil composition of the present invention contains the friction modifier and base oil of the present invention. If the friction modifier contains a base oil, the same base oil as the base oil in the friction modifier may be used, or a different base oil may be used. Examples of base oils used in lubricating oil compositions include mineral oils (solvent-refined oils, paraffin oils, high viscosity index oils containing isoparaffins, high viscosity index oils obtained by hydrocracking of 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. Of these, mineral oils are preferred from the viewpoint of insulating properties.

[0095] The kinematic viscosity of the base oil at 100°C (measured according to JIS-K2283 (2000)) is preferably 1 to 10 mm from the viewpoint of the solubility of copolymer (A). 2 / s, and more preferably 1-4 mm 2 It is / s. The viscosity index of the base oil (measured according to JIS-K2283 (2000)) is preferably 100 or higher, and more preferably 110 or higher, from the viewpoint of viscosity index improvement effect.

[0096] The cloud point of the base oil (measured according to JIS-K2269 (1987)) is preferably -5°C or lower, and more preferably -15°C or lower. When the cloud point of the base oil is within this range, the low-temperature viscosity of the lubricating oil composition is good.

[0097] From the viewpoint of compatibility, the absolute value (ΔSP) of the difference between the SP value of copolymer (A) in the lubricating oil composition and the SP value of the base oil is preferably 0.5 to 3.2 (cal / cm³). 3 ) 1 / 2 And more preferably 0.6 to 2.5 (cal / cm²). 3 ) 1 / 2 Particularly preferred is 0.6 to 2.1 (cal / cm³). 3 ) 1 / 2 And most preferably 0.7 to 1.7 (cal / cm²). 3 ) 1 / 2 That is the case.

[0098] The content of copolymer (A) in the lubricating oil composition of the present invention 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, based on the weight of the lubricating oil composition and from the viewpoint of friction reduction effect.

[0099] The lubricating oil composition of the present invention is suitably used in gear oil (differential oil and industrial gear oil, etc.), MTF, transmission oil [ATF and belt-CVTF, etc.], traction oil (toroidal-CVT F, etc.), shock absorber oil, power steering oil, hydraulic oil (hydraulic oil for construction machinery and industrial hydraulic oil, etc.), and engine oil, and is preferably useful as transmission oil, electric motor oil, or dual-purpose oil for transmissions and electric motors in electric vehicles or hybrid vehicles, and is particularly preferably useful as a dual-purpose oil for transmissions and electric motors in electric vehicles or hybrid vehicles.

[0100] The lubricating oil composition of the present invention may contain various additives. Examples of additives include the following: (1) Viscosity index improvers: (C1-7) alkyl(meth)acrylate / (C8-40) linear or branched alkyl(meth)acrylate copolymer, dispersed monomer (amine monomer, etc.) / (C1-7) alkyl(meth)acrylate / (C8-40) linear or branched alkyl(meth)acrylate copolymer, hydroxyl group-containing monomer / (C1-7) alkyl(meth)acrylate / (C8-40) linear or branched alkyl(meth)acrylate copolymer, comb-shaped polymer [(C1-7) alkyl( [meth)acrylate / (C8-40) linear or branched alkyl (meth)acrylate / polyolefin macromonomer], ethylene / (C1-18) alkyl (meth)acrylate copolymer, alkoxyalkyl (meth)acrylate / polybutylene copolymer macromonomer / (C1-32) linear or branched alkyl (meth)acrylate copolymer, polyisobutylene, polyalkylstyrene, ethylene / propylene copolymer, styrene / maleic acid ester copolymer, styrene / isoprene hydrogenated copolymer, etc.; (2) Cleansing agent: Basic, overbasic, or neutral metal salts [overbasic sulfonates (petroleum sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, etc.) or alkaline earth metal salts, etc.], salicylates, phenates, naphthenates, carbonates, phosphonates, and mixtures thereof; (3) Dispersant: Succinimides (bis- or mono-polybutenyl succinimides), Mannich condensates, borates, etc. (4) Antioxidants: Hindered phenols and aromatic secondary amines, etc. (5) Oiliness improvers: Long-chain fatty acids and their esters (oleic acid and oleic acid esters, etc.), long-chain amines and their amides (oleylamine and oleylamide, etc.), etc. (6) Metallic friction wear modifiers: Molybdenum-based and zinc-based compounds (such as molybdenum dithiophosphate, molybdenum dithiocarbamate, and zinc dialkyldithiophosphate); (7) Extreme pressure agents: Sulfur compounds (mono- or disulfide, sulfoxide, and sulfur phosphide compounds), phosphide compounds, and chlorine compounds (such as chlorinated paraffins); (8) Antifoaming agent: Silicone oils, metal soaps, fatty acid esters, and phosphate compounds, etc. (9) Antiemulsifiers: Quaternary ammonium salts (such as tetraalkylammonium salts), sulfated oils, and phosphates (such as phosphates of polyoxyethylene-containing nonionic surfactants), etc. (10) Corrosion inhibitors: Nitrogen atom-containing compounds (such as benzotriazole and 1,3,4-thiodiazolyl-2,5-bisdialkyldithiocarbamate), etc. (11) Pour point depressants: Polyalkyl methacrylate, polyalkyl acrylate, polyalkylstyrene, polyvinyl acetate, etc.

[0101] 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, metallic friction and wear modifiers, extreme pressure agents, defoamers, anti-emulsifiers, 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. The content of each of these additives is preferably 0.1 to 15% by weight based on the total amount of the lubricating oil composition. Furthermore, the total content of each additive is preferably 0.1 to 30% by weight, more preferably 0.3 to 20% by weight, and even more preferably 3 to 10% by weight based on the total amount of the lubricating oil composition. [Examples]

[0102] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0103] <Manufacturing Example 1> [Manufacturing of Monomer (a-1)] In a reaction vessel equipped with a temperature controller, stirring blades, vacuum device, Liebig condenser, fractionation column, distillate receiving flask, nitrogen inlet and outlet, 260.3 parts by weight (2.0 mol) of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA), 684.8 parts by weight (6.0 mol) of ε-caprolactone, 3.7 parts by weight (0.03 mol) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were added, and the mixture was heated to 115°C while stirring with air flowing through it. The reaction was then carried out at 115°C for 8 hours, and the distillate water was separated. The mixture was then cooled to 25°C, 1 The esterified product was confirmed by 1H-NMR (yield 100 mol%). Monomer (a-1) is A in general formula (1). 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - represents a group represented as -O-, R 1 is an ethylene group, the molar mean of p = 3, R 2 = Pentylene group, R3 It is a monomer represented by a hydrogen atom, and its SP value is 11.04.

[0104] <Manufacturing Example 2> [Manufacturing of Monomer (a-2)] In a reaction vessel equipped with a temperature controller, stirring blades, vacuum device, Liebig condenser, fractionation column, distillate receiving flask, nitrogen inlet and outlet, 260.3 parts by weight (2.0 moles) of HEMA, 913.2 parts by weight (8.0 moles) of ε-caprolactone, 3.7 parts by weight (0.03 moles) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were added, and the mixture was heated to 115°C while stirring with air flowing through. The reaction was then carried out at 115°C for 8 hours, and the distillate was separated. The mixture was then cooled to 25°C, 1 The esterified product was confirmed by 1H-NMR (yield 100 mol%). The monomer (a-2) is A in general formula (1). 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - represents a group represented as -O-, R 1 is an ethylene group, the molar mean of p = 4, R 2 = Pentylene group, R 3 It is a monomer represented by a hydrogen atom, and its SP value is 10.87.

[0105] <Manufacturing Example 3> [Manufacturing of Monomer (a-3)] In a reaction vessel equipped with a temperature controller, stirring blades, vacuum device, Liebig condenser, fractionation column, distillate receiving flask, nitrogen inlet and outlet, 260.3 parts by weight (2.0 moles) of 2-hydroxyethyl methacrylate (HEMA), 228.3 parts by weight (2.0 moles) of ε-caprolactone, 3.7 parts by weight (0.03 moles) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were added, and the mixture was heated to 115°C while stirring with air flowing through. The reaction was then carried out at 115°C for 8 hours, and the distillate was separated. The mixture was then cooled to 25°C, 1The esterification reaction product was confirmed by 1H-NMR (yield 53 mol%). Subsequently, 2-hydroxyethyl methacrylate (HEMA), which remained as an impurity at a concentration of 47 mol%, was removed by silica column chromatography. The monomer (a-3) is A in general formula (1). 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - represents a group represented as -O-, R 1 is an ethylene group, the molar mean of p = 1.9, R 2 = Pentylene group, R 3 It is a monomer represented by a hydrogen atom, and its SP value is 11.36.

[0106] <Manufacturing Example 4> [Manufacturing of monomer (a'-1)] In a reaction vessel equipped with a temperature controller, stirring blades, vacuum device, Liebig condenser, fractionation column, distillate receiving flask, nitrogen inlet and outlet, 260.3 parts by weight (2.0 moles) of 2-hydroxyethyl methacrylate (HEMA), 1141.5 parts by weight (10.0 moles) of ε-caprolactone, 3.7 parts by weight (0.03 moles) of hydroquinone monomethyl ether, and 0.27 parts by weight of butyltris(2-ethylhexanoyloxy)tin were added, and the mixture was heated to 115°C while stirring with air flowing through it. The reaction was then carried out at 115°C for 8 hours, and the distillate was separated. The mixture was then cooled to 25°C, 1 The esterified product was confirmed by 1H-NMR (yield 100 mol%). The monomer (a'-1) is A in general formula (1). 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - represents a group represented as -O-, R 1 is an ethylene group, the molar mean of p = 5, R 2 = Pentylene group, R 3 It is a monomer represented by a hydrogen atom, and its SP value is 10.75.

[0107] <Manufacturing Example 5> [Manufacturing of monomer (a'-2)] A mixture of 60.6 parts by weight (10 moles) of monomer (a-2) obtained by the method described in Production Example 2, 9.1 parts by weight (10 moles) of n-butanoic acid, and 350 parts by weight of dichloromethane was stirred at 0°C. Next, 6.3 parts by weight (5 moles) of 4-dimethylaminopyridine and 24.0 parts by weight (15 moles) of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide were added, and the mixture was warmed to room temperature and stirred overnight. The reaction mixture was washed with 1N hydrochloric acid, aqueous sodium bicarbonate solution, and brine, and the organic layer was dried over magnesium sulfate. The solvent was then removed, and the product was further dried under vacuum to obtain monomer (a'-2). The monomer (a'-2) is A in general formula (1). 1 is a methacryloyl group, -X 1 -, -X 2 - and -X 3 - represents a group represented as -O-, R 1 is an ethylene group, the molar mean of p = 4, R 2 = Pentylene group, R 3 This monomer is represented by a butanoyl group and has an SP value of 9.96. Monomer (a'-2) is not a compound represented by general formula (1).

[0108] <Examples 1-13, Comparative Examples 1-7> In a reaction vessel equipped with a stirrer, heating / cooling device, thermometer, and nitrogen inlet tube, 185 parts by weight of ethyl acetate, a total of 100 parts by weight of the monomer formulations listed in Table 2, and the amounts of dodecyl mercaptan and 2,2'-azobis(2-methylbutyronitrile) listed in Table 2 as chain transfer agents were added. After purging with nitrogen (gas phase oxygen concentration 100 ppm), the mixture was heated to 76°C under a sealed container while stirring, and the polymerization reaction was carried out at the same temperature for 6 hours. Mineral oil [SP value: 8.3 (cal / cm³)] 3 ) 1 / 2 kinematic viscosity at 100℃: 2.4 mm 2 66.7 parts by weight of [viscosity index: 96 / s] were added, the temperature was raised to 120°C, and then unreacted monomers and ethyl acetate were removed over 2 hours under reduced pressure (0.027~0.040 MPa) at the same temperature to obtain friction modifiers (A-1) to (A-13) of the present invention, or friction modifiers (B-1) to (B-7) for comparison, containing 60% by weight of the copolymer.

[0109] The monomers used in the monomer formulations listed in Tables 2 and 3 are as follows: (a-1): HEMA with 3 molar caprolactone adduct (a-2): HEMA caprolactone 4-mol adduct (a-3): HEMA with 1.9 molar caprolactone adduct (a'-1): 5-mol adduct of ε-caprolactone to HEMA (a'-2): Terminal butyl ester of the ε-caprolactone 4-mol adduct of HEMA (b-1): n-dodecyl methacrylate (b-2): Methacrylic acid ester of Neodol23 (manufactured by Shell Chemicals, 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)) (b-3): n-octadecyl methacrylate (b-4): 2-decyltetradecyl methacrylate (b-5): 2-dodecylhexadecyl methacrylate (b-6): 2-tetradecyl octadecyl methacrylate (b-7): n-dodecyl acrylate (b-8): n-octadecyl acrylate (b-9): Methyl methacrylate (b-10): n-butyl methacrylate (c-1): Bremmer PME-200 (methoxy polyethylene glycol methacrylate, R in general formula (3)) 6 is a methyl group, A 2 O is an ethylene oxy group, q ≈ 4, R 7 (This is a methyl group) (c-2): Bremmer PME-400 (Methoxypolyethylene glycol methacrylate, R in general formula (3)) 6 is a methyl group, A 2 O is an ethylene oxy group, q≈9, R 7 (This is a methyl group) (c-3) Bremmer AME-400 (Methoxypolyethylene glycol acrylate, R in general formula (3)) 6 A is a hydrogen atom, A 2 O is an ethylene oxy group, q≈9, R 7 (This is a methyl group)

[0110] <Mw of copolymer> The weight-average molecular weight (Mw) of the copolymers contained in the friction modifiers of Examples 1-13 and Comparative Examples 1-7 was measured under the conditions described in <Measurement conditions for Mw of copolymer (A)>.

[0111] <SP value of copolymer> The SP value of the copolymer was calculated based on the weight fraction of each constituent monomer at the time of preparation.

[0112] <Examples 14-26, Comparative Examples 8-14> The friction modifiers (A-1) to (A-13) obtained in Examples 1 to 13, and the friction modifiers (B-1) to (B-7) obtained in Comparative Examples 1 to 7 were added to the following base oil 1 in an amount of 2% by weight relative to the weight of the base oil (the amount added is calculated on a solid basis), that is, so that the copolymer (A) content in the lubricating oil composition was 2% by weight, to obtain lubricating oil compositions (V-1) to (V-13), (W-1) to (W-4), and (W-7). The friction modifiers obtained in Comparative Examples 5 and 6 did not dissolve in the base oil, so the SRV friction characteristic evaluation test described later was not performed. (1) Base oil 1: Mineral oil [SP value: 8.3 (cal / cm³)] 3 ) 1 / 2 kinematic viscosity at 100℃: 3.1 mm 2 / s, viscosity index: 107]

[0113] <Soluble properties of friction modifiers in base oils> In the production of each of the above lubricating oil compositions, the appearance of each lubricating oil composition at 5 minutes and 1 hour from the start of stirring was observed visually under a fluorescent white light at room temperature of 40°C, and the solubility of friction modifier (A) or (B) in the base oil was evaluated according to the following evaluation criteria. The results are shown in Tables 2 and 3. [Evaluation Criteria] ◎: Dissolved within 1 hour from the start of stirring, with a uniform appearance and no undissolved matter of the copolymer ×: The appearance is non-uniform even after 1 hour from the start of stirring, and undissolved matter of the copolymer is observed

[0114] <Evaluation of SRV Friction Characteristics> Using a dynamic friction and wear tester (SRV tester manufactured by Optimol), the friction coefficients of lubricating oils (V-1) to (V-12), comparative lubricating oils (W-1) to (W-4) and (W-7) in the point contact (load 100 N) between a steel ball and a flat steel disk were measured. The measurement conditions are shown below. The friction coefficient is preferably smaller, and if it is 0.30 or less, it has an excellent friction reduction effect and is preferable. Amplitude: 2 mm, Vibration frequency: 50 Hz, Temperature: 40 °C Time: 10 minutes

[0115]

Table 2

[0116]

Table 3

[0117] As shown in Table 2, it can be seen that the friction modifier of the example is superior in the friction reduction effect to the friction modifiers of the comparative examples shown in Table 3. From this result, it can be seen that according to the present invention, a friction modifier and a lubricating oil composition excellent in the friction reduction effect can be provided.

Claims

1. A friction modifier comprising a copolymer (A) having monomer (a) represented by the following general formula (1), monomer (b) represented by the following general formula (2), and monomer (c) represented by the following general formula (3) as essential constituent monomers, A friction modifier in which the average value of p per mole of monomer (a) in monomer (a) constituting the copolymer (A) is 1 to 4. 【Chemistry 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; p is a number from 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.] 【Chemistry 2】 [In general formula (2), R ４ is a hydrogen atom or a methyl group; -X ４ - represents a group represented by -O- or -NH-; R ５ [It is a linear or branched alkyl group having 1 to 44 carbon atoms.] 【Transformation 3】 [In general formula (3), R ６ is a hydrogen atom or a methyl group; A ２ O is an alkylene oxy group having 1 to 4 carbon atoms, and there are multiple A ２ O can be the same or different; q is a number between 2 and 100; R ７ [This refers to an alkyl group having 1 to 4 carbon atoms.]

2. The friction modifier according to claim 1, wherein the proportion of monomer (c) in the monomers constituting the copolymer (A) is 1 to 30% by weight, based on the total weight of the monomers constituting the copolymer (A).

3. A lubricating oil composition comprising the friction modifier and base oil according to claim 1 or 2.

4. The kinematic viscosity of the base oil at 100°C is 1 to 4 mm². ２ The lubricating oil composition according to claim 3, wherein the value is / s.

5. The lubricating oil composition according to claim 3, further comprising at least one selected from the group consisting of viscosity index improvers, detergents, dispersants, antioxidants, oiliness improvers, metallic friction and wear modifiers, extreme pressure agents, defoamers, anti-emulsifiers, corrosion inhibitors, and pour point depressants.

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