Polymer, friction reducer for lubricating oil, and lubricating oil composition

Abstract

A polymer having a main chain polymer structure and a side chain polymer structure, the side chain polymer structure including constituent units derived from an alkyl (meth) acrylate (a) having 11-30 carbon atoms in an alkyl group, at least one of the main chain polymer structure and the side chain polymer structure contains a constituent unit derived from a (meth) acrylic acid ester (b) represented by general formula (1). In formula (1), R1 represents a hydrogen atom or a methyl group, and R2 represents a hydrogen atom or an organic group containing a polar group. Wherein the organic group containing the polar group does not include alkoxy alkyl. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to a polymer used in engine oil and the like, a friction reducer for lubricating oil, and a lubricating oil composition.

[0002] This application claims priority based on Japanese Patent Application No. 2022-143787 filed in Japan on September 9, 2022, and the contents are incorporated herein by reference. Background Art

[0003] Various antifriction agents are added to lubricating oils such as automobile engine oils and drive train oils to reduce energy loss caused by friction and extend the life of the machine by preventing seizure. In recent years, as lubricating oils have become less viscous in order to save fuel, the load on the contact surface between metals has increased dramatically, and the role of antifriction agents has become more important.

[0004] As antifriction agents, oiliness improvers such as long-chain fatty acid esters and fatty acid amides, anti-wear agents such as phosphate esters and zinc dithiophosphates, extreme pressure agents such as organic sulfur compounds and organic halogen compounds, friction modifiers such as organic molybdenum compounds, etc. can be cited. However, depending on the conditions of use and the use environment, there is a problem that the friction reduction effect is insufficient when only these additives are used. In order to overcome this problem, research on the use of polymer materials as antifriction agents has been conducted. For example, Patent Document 1 discloses that a comb polymer containing repeating units from a polyolefin-based macromolecular monomer and repeating units from a low molecular weight monomer can be preferably used as a friction modifier (friction modifier). In addition, Patent Document 2 discloses that a (meth) acrylic graft copolymer can be preferably used as a friction modifier.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application No. 2020-502344

[0008] Patent Document 2: Japanese Patent Application Publication No. 2022-113676 Summary of the invention

[0009] However, the methods described in Patent Documents 1 and 2 do not have a sufficient effect of reducing friction.

[0010] An object of the present invention is to provide a polymer, and to provide a polymer lubricating oil additive, a friction reducer for lubricating oil, and a lubricating oil composition having a high friction reducing effect by using the polymer.

[0011] [1] A polymer having a main chain polymer structure and a side chain polymer structure,

[0012] The side chain polymer structure comprises a constituent unit derived from an alkyl (meth)acrylate (a) having an alkyl group with 11 to 30 carbon atoms,

[0013] At least one of the main chain polymer structure and the side chain polymer structure includes a structural unit derived from a (meth)acrylic acid ester (b) represented by the following general formula (1).

[0014]

[0015] (Where R 1 is a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an organic group containing a polar group. Among them, the organic group containing a polar group does not include an alkoxyalkyl group.)

[0016] [2] The polymer according to [1], wherein the polar group of the (meth)acrylate (b) is a hydroxyl group, a carboxyl group, an amino group, or an amide group.

[0017] [3] The polymer according to [1] or [2], wherein the polar group of the (meth)acrylate (b) is a hydroxyl group.

[0018] [4] The polymer according to any one of [1] to [3], further comprising a constituent unit derived from an alkyl (meth)acrylate (c) having an alkyl group having 1 to 10 carbon atoms.

[0019] [5] The polymer according to any one of [1] to [4], wherein the main chain polymer structure comprises a constituent unit derived from an alkyl (meth)acrylate (a) having an alkyl group with 11 to 30 carbon atoms.

[0020] [6] The polymer according to any one of [1] to [5], wherein the ratio of the main chain polymer structure is preferably 25 to 98% by mass, more preferably 30 to 95% by mass, and even more preferably 40 to 90% by mass, relative to the total mass of the polymer.

[0021] [7] The polymer according to any one of [1] to [6], wherein the ratio of the side chain polymer structure is preferably 2 to 75% by mass, more preferably 5 to 70% by mass, and even more preferably 10 to 60% by mass, relative to the total mass of the polymer.

[0022] [8] The copolymer according to any one of [1] to [7], wherein the alkyl (meth)acrylate (a) is preferably a linear or branched alkyl (meth)acrylate having 11 to 20 carbon atoms, more preferably a linear or branched alkyl methacrylate having 11 to 20 carbon atoms, further preferably a linear or branched alkyl methacrylate having 11 to 18 carbon atoms, and particularly preferably a linear or branched alkyl methacrylate having 12 to 14 carbon atoms.

[0023] [9] The polymer according to any one of [1] to [8], wherein the content of the structural unit derived from the (meth)acrylate (a) is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, and even more preferably 80 to 99% by mass, relative to the total mass of the side chain polymer structure.

[0024]

[10] The polymer according to any one of [1] to [9], wherein the content of the structural unit derived from the (meth)acrylate (a) is preferably 20 to 90% by mass, more preferably 25 to 85% by mass, and even more preferably 30 to 80% by mass, relative to the total mass of the polymer.

[0025]

[11] The polymer according to any one of [1] to

[10] , wherein the polar group of the (meth)acrylate (b) is preferably a hydroxyl group, a carboxyl group, an aliphatic heterocycle having 2 to 6 carbon atoms, an aromatic heterocycle having 4 to 10 carbon atoms, an alkoxysilyl group, a trialkoxysilyl group having 3 to 9 carbon atoms, a phosphoric acid group, a phosphoric acid ester group, an amino group or an amide group; more preferably a hydroxyl group, a carboxyl group, an amino group or an amide group; and even more preferably a hydroxyl group.

[0026]

[12] The polymer according to any one of [1] to

[11] , wherein the total number of carbon atoms in the (meth)acrylate (b) is preferably 3 to 10, more preferably 3 to 9, and even more preferably 3 to 8.

[0027]

[13] The copolymer according to any one of [1] to

[12] , wherein the content of the structural unit derived from the (meth)acrylate (b) is preferably 0.01% by mass to 20% by mass, more preferably 0.05% by mass to 15% by mass, further preferably 0.1% by mass to 5% by mass, and particularly preferably 0.5% by mass to 3% by mass, relative to the total mass of the polymer.

[0028]

[14] The polymer according to any one of [1] to

[13] , further comprising a constituent unit derived from an alkyl (meth)acrylate (c) having an alkyl group having 1 to 10 carbon atoms.

[0029]

[15] The polymer according to any one of [1] to

[14] , further comprising a constituent unit derived from an alkyl (meth)acrylate having 1 to 10 carbon atoms in the alkyl group (c), wherein the alkyl (meth)acrylate (c) is preferably an alkyl (meth)acrylate having 1 to 4 carbon atoms, more preferably an alkyl acrylate having 1 to 4 carbon atoms, and even more preferably n-butyl acrylate.

[0030]

[16] The polymer according to any one of [1] to

[15] , further comprising a constituent unit derived from an alkyl (meth)acrylate (c) having an alkyl group with 1 to 10 carbon atoms, wherein the content of the constituent unit derived from the alkyl (meth)acrylate (c) is preferably 20% to 95% by mass, more preferably 30% to 90% by mass, and even more preferably 45% to 80% by mass, relative to the total mass of the polymer.

[0031]

[17] The polymer according to any one of [1] to

[16] , wherein the total content of the constituent units derived from the (meth)acrylate (a), the constituent units derived from the (meth)acrylate (b) represented by the general formula (1), and the constituent units derived from the (meth)acrylate (c) having an alkyl group with 1 to 10 carbon atoms is preferably 70 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass, relative to the total mass of the polymer.

[0032]

[18] A polymer according to any one of [1] to

[17] , wherein the main chain polymer structure comprises constituent units derived from a vinyl-based free radical polymerizable monomer (m1), and at least a portion of the constituent units derived from the vinyl-based free radical polymerizable monomer (m1) are constituent units derived from the (meth)acrylate (b).

[0033]

[19] The polymer according to any one of [1] to

[18] , wherein the side chain polymer structure comprises a structural unit derived from a macromonomer (M).

[0034]

[20] The polymer according to

[19] , wherein the macromonomer (M) comprises a constituent unit of the (meth)acrylic acid alkyl ester (a) having 11 to 30 carbon atoms derived from the alkyl group.

[0035]

[21] The polymer according to

[19] or

[20] , wherein the macromonomer (M) has a structure represented by the following formula (2).

[0036]

[0037] (Where X 1 ~X n－1Each independently represents a hydrogen atom, a methyl group or CH2OH, Y 1 ~Y n Each independently represents a vinyl group bonded to the vinyl radical polymerizable monomer (m2) as a monomer constituent unit of the macromonomer (M), except X 1 ~X n－1 Z represents a terminal group, and n represents an integer from 2 to 10000.

[0038]

[22] A polymer according to any one of

[18] to

[21] , wherein the vinyl radical polymerizable monomer (m1) comprises a (meth)acrylate (b) represented by the general formula (1) and an alkyl (meth)acrylate (c) having an alkyl group with 1 to 10 carbon atoms.

[0039]

[23] The polymer according to any one of

[18] to

[22] , wherein the vinyl radical polymerizable monomer (m2) contains the (meth)acrylate (a).

[0040]

[24] A polymer according to any one of

[19] to

[23] , wherein the content of the constituent units derived from the (meth)acrylate (a) is preferably 80 to 100% by mass, more preferably 85 to 99.9% by mass, further preferably 90 to 99.8% by mass, and particularly preferably 95 to 99.5% by mass, relative to the total mass of the macromonomer (M).

[0041]

[25] A polymer according to any one of

[19] to

[24] , wherein the content of the constituent units derived from the (meth)acrylic acid alkyl ester (c) having 1 to 10 carbon atoms in the alkyl group is preferably greater than 0 mass% and less than 20 mass%, more preferably 0.1 to 15 mass%, further preferably 0.2 to 10 mass%, and particularly preferably 0.5 to 5 mass%, relative to the total mass of the above-mentioned macromonomer (M).

[0042]

[26] The polymer according to any one of

[18] to

[25] , wherein the ratio represented by [the content of the constituent units derived from the (meth)acrylic acid alkyl ester (c) having an alkyl group with 1 to 10 carbon atoms] / [the content of the constituent units derived from the above-mentioned (meth)acrylic acid alkyl ester (a)] is preferably 0.001 to 3.5, more preferably 0.002 to 3.0, and even more preferably 0.005 to 2.6.

[0043]

[27] The polymer according to any one of

[19] to

[26] , wherein the content of the structural unit derived from the macromonomer (M) is preferably 1 to 70% by mass, more preferably 2 to 60% by mass, and even more preferably 5 to 50% by mass, relative to the total mass of the polymer.

[0044]

[28] The polymer according to any one of

[19] to

[27] , wherein the mass average molecular weight (Mw) of the macromonomer (M) measured by gel permeation chromatography is preferably 2,000 to 100,000, more preferably 3,000 to 80,000, further preferably 4,000 to 50,000, and particularly preferably 5,000 to 30,000.

[0045]

[29] The polymer according to any one of

[19] to

[28] , wherein the number average molecular weight (Mn) of the macromonomer (M) measured by gel permeation chromatography (GPC) is preferably 500 to 30,000, more preferably 1,000 to 25,000, further preferably 2,000 to 20,000, and particularly preferably 3,000 to 16,000.

[0046]

[30] The polymer according to any one of

[19] to

[29] , wherein the molecular weight distribution (Mw / Mn) of the macromonomer (M) measured by gel permeation chromatography is preferably 1.0 to 5.0, more preferably 1.3 to 3.0, and even more preferably 1.5 to 2.5.

[0047]

[31] The polymer according to any one of [1] to

[30] , wherein the mass average molecular weight (Mw) of the polymer measured by GPC is preferably 10,000 to 500,000, more preferably 15,000 to 300,000, and even more preferably 20,000 to 200,000.

[0048]

[32] The polymer according to any one of [1] to

[31] , wherein the number average molecular weight (Mn) of the polymer measured by gel permeation chromatography (GPC) is preferably 5,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 15,000 to 50,000.

[0049]

[33] The polymer according to any one of [1] to

[32] , wherein the molecular weight distribution (Mw / Mn) of the polymer measured by gel permeation chromatography (GPC) is preferably 1.0 to 15, more preferably 2.0 to 10, and even more preferably 3.0 to 8.0.

[0050]

[34] A polymer according to any one of [1] to

[33] , wherein a base oil solution containing 2% by mass of the polymer is prepared, and the friction coefficient measured at 40°C using an SRV5 tester (manufactured by Optimol Instruments Pruftechnik GmbH) is preferably 0.16 or less, more preferably 0.155 or less, and even more preferably 0.15 or less.

[0051]

[35] A lubricating oil additive comprising the polymer described in any one of [1] to

[34] .

[0052]

[36] A friction reducer for lubricating oil, comprising the polymer according to any one of [1] to

[34] and a solvent.

[0053]

[37] The friction reducer for lubricating oil according to

[36] , wherein the solvent is a base oil.

[0054]

[38] The friction reducer for lubricating oil according to

[37] , wherein the base oil is a base oil of API standard Group III, a base oil of API standard Group III+, or a base oil of API standard Group IV.

[0055]

[39] The friction reducer for lubricating oil according to any one of

[36] to

[38] , wherein the content of the above polymer is preferably 10 to 80 mass %, more preferably 15 to 70 mass %, and even more preferably 20 to 60 mass %, when the total mass of the lubricating oil additive is set to 100 mass %.

[0056]

[40] A lubricating oil composition comprising the friction reducer for lubricating oil according to any one of

[36] to

[39] .

[0057]

[41] The lubricating oil composition according to

[40] , wherein the content of the friction reducer for lubricating oil is preferably 0.01 to 30 mass %, more preferably 0.05 to 25 mass %, and even more preferably 0.1 to 20 mass %, when the total mass of the lubricating oil composition is set to 100 mass %.

[0058]

[42] Use of the polymer according to any one of [1] to

[34] for producing a lubricating oil composition.

[0059]

[43] Use of the polymer described in any one of [1] to

[34] for reducing friction.

[0060]

[44] Use of the polymer described in any one of [1] to

[34] for improving lubricity.

[0061]

[45] Use of a composition comprising the polymer described in any one of [1] to

[34] for reducing friction.

[0062]

[46] Use of a composition comprising the polymer described in any one of [1] to

[34] for improving lubricity.

[0063]

[47] The use according to

[45] or

[46] , wherein the composition contains a solvent.

[0064]

[48] ​​The use according to

[47] , wherein the solvent is a base oil.

[0065]

[49] The use according to

[48] , wherein the base oil is a base oil of API standard Group III, a base oil of API standard Group III+, or a base oil of API standard Group IV.

[0066]

[50] The use according to any one of

[45] to

[49] , wherein the content of the above polymer is preferably 0.01 to 30% by mass, more preferably 0.05 to 25% by mass, and even more preferably 0.1 to 20% by mass, when the total mass of the composition is set to 100% by mass.

[0067] Furthermore, the present invention has the following aspects.

[0068] [1] A friction reducer for lubricating oil, comprising a (meth)acrylic acid graft copolymer A having a main chain polymer structure and a side chain polymer structure, wherein the (meth)acrylic acid graft copolymer A contains constituent units derived from a (meth)acrylic acid alkyl ester (a) having an alkyl group with 11 to 30 carbon atoms in the side chain polymer structure, and contains constituent units derived from a (meth)acrylic acid ester (b) represented by the following general formula (1).

[0069]

[0070] (Where R 1 is a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an organic group containing a polar group. Among them, the organic group containing a polar group does not include alkoxyalkyl.)

[0071] [2] The friction reducer for lubricating oil according to [1], wherein the polar group of the (meth)acrylate (b) is a hydroxyl group, a carboxyl group, an amino group or an amide group.

[0072] [3] The friction reducer for lubricating oil according to [1], wherein the polar group of the (meth)acrylate (b) is a hydroxyl group.

[0073] [4] The friction reducer for lubricating oil according to any one of [1] to [3], wherein the (meth)acrylic graft copolymer A further contains constituent units derived from an alkyl (meth)acrylate having an alkyl group with 1 to 10 carbon atoms (c).

[0074] [5] The friction reducer for lubricating oil according to any one of [1] to [4], wherein the (meth)acrylic graft copolymer A contains constituent units derived from an alkyl (meth)acrylate having 11 to 30 carbon atoms in the alkyl group in the main chain polymer structure.

[0075] [6] The friction reducer for lubricating oil according to any one of [1] to [5], wherein the (meth)acrylic graft copolymer A comprises a constituent unit derived from a vinyl radical polymerizable monomer (m1) and a constituent unit derived from a macromonomer (M).

[0076] [7] The friction reducer for lubricating oil according to [6], wherein the macromonomer (M) comprises a constituent unit derived from the (meth)acrylic acid alkyl ester (a) having an alkyl group having 11 to 30 carbon atoms.

[0077] [8] The friction reducer for lubricating oil according to [6], wherein the macromonomer (M) has a structure represented by the following formula (2).

[0078]

[0079] (Where X 1 ~X n－1 Each independently represents a hydrogen atom, a methyl group or CH2OH, Y 1 ~Y n Each independently represents a vinyl group bonded to the vinyl radical polymerizable monomer (m2) as a monomer constituent unit of the macromonomer (M), except X 1 ~X n－1 Z represents a terminal group, and n represents an integer from 2 to 10000.

[0080] [9] A lubricating oil composition comprising the friction reducer for lubricating oil according to any one of [1] to [8].

[0081] According to the polymer of the present invention, a lubricating oil additive, a friction reducer for lubricating oil, and a lubricating oil composition having a high friction reducing effect can be provided. DETAILED DESCRIPTION

[0082] The present invention will be described in detail below. The following embodiments are merely examples for describing the present invention and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various ways without departing from the gist thereof.

[0083] It should be noted that in the present invention, "(meth)acrylic acid" is a general term for "acrylic acid" and "methacrylic acid". "(Meth)acrylate" is a general term for "acrylate" and "methacrylate". "(Meth)acryloyl" is a general term for "acryloyl" and "methacryloyl", and is a group represented by CH2=C(R)-C(=O)- (R is a hydrogen atom or a methyl group). "Macromer" refers to a polymer having a free radical polymerizable group or an addition reactive functional group. "Vinyl-based free radical polymerizable monomer" refers to a monomer having an ethylenically unsaturated bond that is not a macromonomer.

[0084] The polymer of the present invention has a main chain polymer structure and a side chain polymer structure, wherein the side chain polymer structure includes a constituent unit derived from an alkyl (meth)acrylate (a) having an alkyl group with 11 to 30 carbon atoms, and at least one of the main chain polymer structure and the side chain polymer structure includes a constituent unit derived from a (meth)acrylate (b) represented by the following general formula (1).

[0085]

[0086] (Where R 1 is a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an organic group containing a polar group. Among them, the organic group containing a polar group does not include an alkoxyalkyl group.)

[0087] The friction reducer for lubricating oil contains a polymer.

[0088] The polymer is a copolymer in which at least a part of the constituent units are constituent units derived from a (meth)acrylic monomer. The polymer may further include constituent units derived from a monomer other than the (meth)acrylic monomer (for example, styrene, etc.).

[0089] The above-mentioned polymer is preferably a graft copolymer composed of a main chain polymer structure and a side chain polymer structure (branched polymer structure) chemically bonded to the main chain polymer structure (trunk polymer structure). In this specification, a graft copolymer refers to a polymer having one or more blocks connected to the main chain polymer structure as a side chain polymer structure. The structures of the main chain polymer and the side chain polymer may be different or the same. There are no particular restrictions on the method for producing the graft copolymer, and examples include a method of producing a side chain polymer structure by free radical polymerization with a monomer as a constituent unit of the main chain polymer after a macromolecular monomer having a free radical polymerizable double bond at the end is produced; a method of reacting a main chain polymer having a reaction site and a macromolecular monomer having a reaction site in advance; a method of producing a side chain polymer structure by using an initiator having hydrogen abstraction ability to produce free radicals on the main chain polymer after the main chain polymer is produced and reacting the free radicals with the monomer as a constituent unit of the side chain polymer, etc.

[0090] The polymer is preferably a graft copolymer containing constituent units derived from an alkyl (meth)acrylate having 11 to 30 carbon atoms in the alkyl group (a) (hereinafter also referred to as "component (a)") in the side chain polymer structure and constituent units derived from a (meth)acrylate (b) (hereinafter also referred to as "component (b)") represented by the general formula (1).

[0091] Examples of the component (a) include n-undecyl (meth)acrylate, iso-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, iso-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, iso-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, iso-tetradecyl (meth)acrylate, n-cetyl (meth)acrylate, isocetyl (meth)acrylate, n-stearyl (meth)acrylate, isostearyl (meth)acrylate, n-octadecyl (meth)acrylate, iso-octadecyl (meth)acrylate, n-behenyl (meth)acrylate, and iso-behenyl (meth)acrylate. Two or more of these may be used in combination.

[0092] From the viewpoint of excellent solubility in the base oil and friction reducing effect, as the component (a), a linear or branched alkyl (meth)acrylate having 11 to 20 carbon atoms is preferred, a linear or branched alkyl methacrylate having 11 to 20 carbon atoms is more preferred, a linear or branched alkyl methacrylate having 11 to 18 carbon atoms is further preferred, and a linear or branched alkyl methacrylate having 12 to 14 carbon atoms is particularly preferred.

[0093] In addition, from the viewpoint of improving the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the content of the structural units derived from the component (a) is preferably 30% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more, based on the total mass of the side chain polymer structure.

[0094] In order to improve the solubility and friction-reducing performance in the base oil and to improve the fuel efficiency by reducing the viscosity of the lubricating oil composition, the content of the structural units derived from the component (a) is preferably 20 to 90% by mass, more preferably 25 to 85% by mass, and even more preferably 30 to 80% by mass based on the total mass of the polymer.

[0095] From the viewpoint of improving the solubility of the polymer in the base oil, the polymer preferably contains the constituent unit derived from the component (a) as a constituent unit also in the main chain polymer structure.

[0096] The component (b) is a (meth)acrylate represented by the following general formula (1) (hereinafter, the (meth)acrylate (b) represented by the following general formula (1) is also referred to as "polar group-containing (meth)acrylate (b)").

[0097]

[0098] (Where R 1 is a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an organic group containing a polar group. Among them, the organic group containing a polar group does not include an alkoxyalkyl group.)

[0099] Examples of the polar group include a hydroxyl group, a carboxyl group, a heterocyclic structure (e.g., an aliphatic heterocyclic ring having 2 to 6 carbon atoms, an aromatic heterocyclic ring having 4 to 10 carbon atoms), an alkoxysilyl group, a trialkoxysilyl group having 3 to 9 carbon atoms, a phosphoric acid group, a phosphoric acid ester group, an amino group (e.g., secondary amino groups such as dimethylamino and diethylamino), and an amide group. Examples of the component (b) include (meth)acrylates having a hydroxyl group such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, glycerol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, and polypropylene glycol mono(meth)acrylate; (meth)acrylates containing a carboxyl group such as (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, and 2-(meth)acryloyloxyethyl hexahydrophthalate; (Meth)acrylates having a heterocyclic structure such as tetrahydrofurfuryl (meth)acrylate and glycidyl (meth)acrylate; (meth)acrylates having a trialkoxysilyl group having 3 to 9 carbon atoms such as 3-(meth)acryloxypropyltrimethoxysilane and 3-(meth)acryloxypropyltriethoxysilane; (meth)acrylates having a phosphate group such as 2-(meth)acryloxyethyl acid phosphate; (meth)acrylates having an amino group such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate; (meth)acrylates having an amide group such as (meth)acrylamide, dimethyl(meth)acrylamide, and diethyl(meth)acrylamide, etc. These may be used in combination of two or more. As the above-mentioned (meth)acrylate (b) containing a polar group, a (meth)acrylate having a hydroxyl group or a carboxyl group is preferred, a (meth)acrylate having a hydroxyl group or a carboxyl group is more preferred, a (meth)acrylate having a hydroxyl group is more preferred, and an acrylate having a hydroxyl group is particularly preferred. The total number of carbon atoms in the polar group-containing (meth)acrylate (b) is preferably 3 to 10, more preferably 3 to 9, and even more preferably 3 to 8.

[0100] Among the organic groups having polar groups, those having large polarity are more preferably used. For example, hydroxyl, carboxyl, amino, amide, phosphoric acid, and phosphoric acid ester groups have larger polarity than alkoxyalkyl groups and are preferred polar groups.

[0101] By having a polar group with a large polarity, the polymer can improve its affinity with the metal surface through the action of intermolecular forces such as van der Waals force and hydrogen bond, and the formation of chemical bonds such as covalent bond and ionic bond. As a result, the adhesion of the polymer to the metal surface is improved, and the friction reduction performance can be improved.

[0102] From the viewpoint of improving the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the content of the structural units derived from the component (b) is preferably 0.01% by mass to 20% by mass, more preferably 0.05% by mass to 15% by mass, further preferably 0.1% by mass to 5% by mass, and particularly preferably 0.5% by mass to 3% by mass, relative to the total mass of the polymer.

[0103] From the viewpoint of being able to improve the friction reduction performance and enhance the fuel economy by reducing the viscosity of the lubricating oil composition, the above polymer preferably further contains a (meth)acrylic acid alkyl ester (c) having an alkyl group with 1 to 10 carbon atoms (hereinafter also referred to as "component (c)") as a constituent unit.

[0104] As the component (c), for example, there can be mentioned (meth)acrylates having a linear alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, and n-nonyl (meth)acrylate; (meth)acrylates having a branched alkyl group such as isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; and (meth)acrylates having a cyclic alkyl group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentyl (meth)acrylate, isobornyl (meth)acrylate, and 4-tert-butylcyclohexyl (meth)acrylate. Two or more of these can be used in combination.

[0105] From the viewpoint of excellent friction reducing effect, a (meth)acrylic acid alkyl ester having 1 to 4 carbon atoms is preferred, an acrylate alkyl ester having 1 to 4 carbon atoms is more preferred, and n-butyl acrylate is further preferred.

[0106] From the viewpoint of excellent friction-reducing effect, the structural unit derived from the component (c) is preferably contained in the main chain polymer structure.

[0107] From the viewpoint of improving the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the content of the structural units derived from the component (c) is preferably 20% by mass to 95% by mass, more preferably 30% by mass to 90% by mass, and even more preferably 45% by mass to 80% by mass, relative to the total mass of the polymer.

[0108] From the aspect of being able to make the friction reduction performance good, the total amount of the constituent units from the above-mentioned components (a) to (c) relative to the total mass of the above-mentioned polymer is preferably 70 mass % or more, more preferably 80 mass % or more, and further preferably 90 mass % or more. The total amount of the constituent units from the above-mentioned components (a) to (c) relative to the total mass of the above-mentioned polymer does not exceed 100 mass %.

[0109] The above polymer may contain a structural unit derived from another radically polymerizable vinyl compound (d) (hereinafter also referred to as "component (d)") other than the above components (a) to (c).

[0110] Examples of the component (d) include styrene, α-methylstyrene, p-tert-butylstyrene, vinyltoluene, vinyl acetate, and (meth)acrylates other than the components (a) to (c). Other (meth)acrylates include (meth)acrylates having an aromatic ring structure such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, phenoxypolypropylene glycol (meth)acrylate, phenylphenyl (meth)acrylate, phenylphenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, phenylbenzyl (meth)acrylate, naphthyl (meth)acrylate, and (1-naphthyl)methyl (meth)acrylate; (meth)acrylate alkoxy esters such as methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and butoxyethyl (meth)acrylate; and trifluoroethyl (meth)acrylate and heptadecafluorodecyl (meth)acrylate. Two or more of these may be used in combination.

[0111] The polymer may contain the structural unit derived from the components (a) to (d) as a structural unit in any of the main chain polymer structure and the side chain polymer structure.

[0112] The polymer may include constituent units derived from a vinyl radical polymerizable monomer (m1) (hereinafter also referred to as "component (m1)") and constituent units derived from a macromonomer (M) (hereinafter also referred to as "component (M)"). The component (M) includes constituent units derived from a monomer (m2) having a vinyl radical polymerizable group.

[0113] Examples of the component (m1) include styrene, vinyl acetate, and (meth)acrylate compounds. Examples of the (meth)acrylate compounds include (meth)acrylates having a linear alkyl group such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, n-decyl (meth)acrylate, n-undecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, n-cetyl (meth)acrylate, n-stearyl (meth)acrylate, and n-behenyl (meth)acrylate; (Meth)acrylates having a branched alkyl group such as isopropyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, isopentyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, 3-isopropylheptyl (meth)acrylate, isoundecyl (meth)acrylate, 2-tert-butylheptyl (meth)acrylate, isododecyl (meth)acrylate, isotridecyl (meth)acrylate, isotetradecyl (meth)acrylate, isobehenyl (meth)acrylate; cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, (Meth)acrylates having a cyclic alkyl group, such as dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and adamantyl (meth)acrylate; (meth)acrylates having a hydroxyl group, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, glycerol mono(meth)acrylate, ethylene glycol mono(meth)acrylate, and propylene glycol mono(meth)acrylate; (meth)acrylic acid, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, and the like. (Meth)acrylates containing a carboxyl group, such as (meth)acryloyloxyethyl and 2-(meth)acryloyloxyethyl hexahydrophthalate; (meth)acrylates having an aromatic ring structure, such as phenyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, nonylphenoxypolyethylene glycol (meth)acrylate, phenoxypolypropylene glycol (meth)acrylate, phenylphenyl (meth)acrylate, phenylphenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, phenylbenzyl (meth)acrylate, naphthyl (meth)acrylate, and (1-naphthyl)methyl (meth)acrylate;(Meth)acrylates having a heterocyclic structure such as tetrahydrofurfuryl (meth)acrylate, glycidyl (meth)acrylate, and (meth)acryloylmorpholine; (meth)acrylate alkoxy esters such as methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and butoxyethyl (meth)acrylate; allyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 2-(meth)acryloxyethyl acid phosphate, trifluoroethyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and (meth)acrylamide. Two or more of these may be used in combination. ;

[0114] From the viewpoint of enhancing the friction-reducing effect, it is preferred that the component (m1) contain the component (b) and the component (c).

[0115] The above-mentioned (M) component is a compound containing two or more constituent units derived from a monomer (m2) having a vinyl-based free radical polymerizable group (hereinafter, also referred to as "(m2) component"), and having a free radical polymerizable group at the terminal, and contains the above-mentioned (a) component as the (m2) component. As the (m2) component other than the (a) component, the compounds listed as the above-mentioned (m1) component can be mentioned.

[0116] From the viewpoint of improving the solubility of the polymer in the base oil, the constituent units derived from the component (a) are preferably contained in an amount of 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, and particularly preferably 80% by mass or more, relative to the total mass of the component (M). The constituent units derived from the component (a) may be 100% by mass, but are preferably less than 100% by mass, relative to the total mass of the component (M).

[0117] From the perspective of being able to improve the solubility of the polymer in the base oil, the content of the structural units derived from the component (c) is preferably greater than 0% by mass and less than 20% by mass, more preferably 0.1 to 15% by mass, further preferably 0.2 to 10% by mass, and particularly preferably 0.5 to 5% by mass, relative to the total mass of the component (M).

[0118] From the viewpoint of improving the solubility of the polymer in the base oil, the ratio represented by [the content of the structural units derived from the component (c)] / [the content of the structural units derived from the component (a)] is preferably 0.001 to 3.5, more preferably 0.002 to 3.0, and even more preferably 0.005 to 2.6.

[0119] Furthermore, from the viewpoint of radical polymerizability, the component (M) preferably has a structure represented by the following formula (2).

[0120]

[0121] (Where X 1 ~X n－1 Each independently represents a hydrogen atom, a methyl group or CH2OH, Y 1 ~Y n Each independently represents a monomer unit bonded to the vinyl group of the component (m2) except X 1 ~X n－1 Z represents a terminal group, and n represents an integer from 2 to 10000.

[0122] X 1 ~X n－1 and Y 1 ~Y n Each is independently a substituent bonded to the vinyl group of the component (m2). 1 ~Y n For example, to express OR 1 , halogen atoms, COR 2 、COOR 3 、CN、CONR 4 R 5 、NHCOR 6 or R 7 , R 1 ~R 7 Each independently represents a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group or the like.

[0123] In addition, Z of the terminal group is similar to the terminal group of a polymer obtained by known radical polymerization, and examples thereof include a hydrogen atom and a group derived from a radical polymerization initiator.

[0124] In addition, from the perspective of being able to improve the solubility of the polymer in the base oil and the aspect of being able to improve the friction reducing effect, the content of the structural units derived from the above-mentioned (M) component is preferably 1 to 70 mass %, more preferably 2 to 60 mass %, and further preferably 5 to 50 mass %, relative to the total mass of the compound.

[0125] The mass average molecular weight (Mw) of the macromonomer (M) as measured by gel permeation chromatography is preferably 2,000 to 100,000, more preferably 3,000 to 80,000, further preferably 4,000 to 50,000, and particularly preferably 5,000 to 30,000, from the viewpoint of improving the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition.

[0126] The number average molecular weight (Mn) of the macromonomer (M) as measured by gel permeation chromatography (GPC) is preferably 500 to 30,000, more preferably 1,000 to 25,000, further preferably 2,000 to 20,000, and particularly preferably 3,000 to 16,000, from the viewpoint of improving the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition.

[0127] The molecular weight distribution (Mw / Mn) of the macromonomer (M) as measured by gel permeation chromatography is preferably 1.0 to 5.0, more preferably 1.3 to 3.0, and even more preferably 1.5 to 2.5, from the viewpoint of being able to improve the solubility and friction-reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition.

[0128] The above-mentioned (M) component may be a monomer produced by a known method or a commercially available monomer. As the production method of the (M) component, for example, there can be cited a method using a cobalt chain transfer agent (U.S. Patent No. 4,680,352), a method using an α-substituted unsaturated compound such as α-bromomethylstyrene as a chain transfer agent (International Publication No. 88 / 04304), a method of chemically bonding a polymerizable group (Japanese Patent Publication No. 60-133007 and U.S. Patent No. 5,147,952), and a method based on thermal decomposition (Japanese Patent Publication No. 11-240854).

[0129] The method using a cobalt chain transfer agent is preferred because the number of production steps is small and a catalyst with a high chain transfer constant is used. Since the cobalt chain transfer agent has a high chain transfer constant, a macromonomer with a controlled molecular weight can be obtained by adding a small amount of the cobalt chain transfer agent.

[0130] As the cobalt chain transfer agent, a known cobalt complex can be used. The amount of the cobalt chain transfer agent is preferably 0.00001 to 0.1 parts by mass, more preferably 0.00005 to 0.05 parts by mass, and particularly preferably 0.0001 to 0.02 parts by mass, based on 100 parts by mass of the component (m2).

[0131] In addition, from the viewpoint of being able to improve the solubility and friction reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the mass average molecular weight (Mw) of the polymer contained in the friction reducer for lubricating oil of the present invention measured by GPC is preferably 10,000 to 500,000, more preferably 15,000 to 300,000, and even more preferably 20,000 to 200,000.

[0132] In addition, from the viewpoint of being able to improve the solubility and friction reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the number average molecular weight (Mn) of the polymer A contained in the friction reducer for lubricating oil of the present invention, as measured by gel permeation chromatography (GPC), is preferably 5,000 to 100,000, more preferably 10,000 to 80,000, and even more preferably 15,000 to 50,000.

[0133] In addition, from the viewpoint of being able to improve the solubility and friction reducing performance in the base oil and improving the fuel efficiency by reducing the viscosity of the lubricating oil composition, the molecular weight distribution (Mw / Mn) of the polymer A contained in the friction reducer for lubricating oil of the present invention as measured by gel permeation chromatography (GPC) is preferably 1.0 to 15, more preferably 2.0 to 10, and even more preferably 3.0 to 8.0.

[0134] An example of the method for producing the friction reducing agent for lubricating oil of the present invention is shown.

[0135] The friction reducer for lubricating oil of the present invention can be produced by polymerizing a monomer mixture containing the above-mentioned alkyl (meth)acrylates (a) to (c), the above-mentioned other radical polymerizable vinyl compound (d), and the macromonomer (M) in a base oil by a known method.

[0136] The base oil is not particularly limited, and examples thereof include API Group III base oils such as YUBASE 3 manufactured by SK Lubricants, API Group III+ base oils such as YUBASE 4 manufactured by SK Lubricants, and API Group IV base oils such as poly-α-olefins.

[0137] The polymerization may be carried out under known conditions, and it is preferred to use an α-methylstyrene dimer as a chain transfer agent because of its particularly excellent effect of suppressing heat generation during polymerization.

[0138] The friction reducer for lubricating oil containing the polymer of the present invention can be used as a friction reducer for lubricating oil added to lubricating oils such as engine oil, drive train oil (gear oil, transmission oil), hydraulic oil, metalworking oil, etc. used in mobile devices such as automobiles and ships, industrial machinery, robots, etc.

[0139] Examples of the base oils for the engine oil, gear oil, hydraulic oil, etc. include mineral base oils purified from crude oil and chemically synthesized synthetic oils. For example, there can be mentioned base oils of API Group III such as YUBASE 3 manufactured by SK Lubricants, base oils of API Group III+ such as YUBASE 4 manufactured by SK Lubricants, and base oils of API Group IV such as polyalphaolefins.

[0140] The lubricating oil composition of the present invention is obtained by blending the friction reducer for lubricating oil of the present invention into a base oil. The lubricating oil composition of the present invention may also contain other additives in addition to the friction reducer for lubricating oil of the present invention. As other additives, antioxidants, viscosity index improvers, pour point depressants, detergent dispersants, preservatives, rust inhibitors, defoamers, emulsifiers, mildew inhibitors, anti-emulsifiers, etc. can be cited. In addition, as friction reducers other than the present invention, oiliness improvers such as long-chain fatty acid esters and fatty acid amides, anti-wear agents such as phosphate esters and zinc dithiophosphates, extreme pressure agents such as organic sulfur compounds and organic halogen compounds, friction modifiers such as organic molybdenum compounds, etc. can be contained.

[0141] The lubricating oil composition of the present invention may also be a grease containing a thickener. Examples of the thickener include soap-based (lithium soap, calcium soap, sodium soap, aluminum soap, etc.), inorganic-based (bentonite, silica gel, etc.), and organic-based (polyurea, polyurethane, etc.).

[0142] When the total mass of the lubricating oil composition is 100 mass %, the content of the friction reducer for lubricating oil of the present invention contained in the above-mentioned lubricating oil composition is preferably 0.01 to 30 mass %, more preferably 0.05 to 25 mass %, and further preferably 0.1 to 20 mass %. When the content of the friction reducer for lubricating oil is 0.01 mass % or more, the friction reducing effect of the lubricating oil composition is improved, and when it is 30 mass % or less, the kinematic viscosity of the lubricating oil composition at low temperature is reduced, and the fuel efficiency is improved.

[0143] The friction coefficient of a base oil solution containing 2 mass % of the polymer and measured at 40° C. using an SRV5 tester (manufactured by Optimol Instruments Pruftechnik GmbH) is preferably 0.16 or less, more preferably 0.155 or less, and even more preferably 0.15 or less.

[0144] Example

[0145] Hereinafter, the present invention will be described in more detail based on examples and comparative examples. It should be noted that "parts" in the examples represent "parts by mass". In addition, in Tables 1 to 6, the content of the constituent units from each monomer is expressed in mass %. The content of each constituent unit is calculated from the mass of the monomer relative to the total mass of the monomers used in the polymerization reaction. Evaluation was performed by the following method.

[0146] <Molecular weight of macromonomer (M)>

[0147] The measurement was performed using GPC (HLC-8320 manufactured by Tosoh Corporation). After preparing a 0.2 mass % tetrahydrofuran solution of the macromonomer (M), 10 μl of the solution was injected into a device equipped with chromatographic columns manufactured by Tosoh Corporation (TSKgel SuperHZM-M (inner diameter 4.6 mm, length 15 cm), HZM-M (inner diameter 4.6 mm, length 15 cm), HZ-2000 (inner diameter 4.6 mm, length 15 cm), TSKguardcolumn SuperHZ-L (inner diameter 4.6 mm, length 3.5 cm), and the measurement was performed under the conditions of flow rate: 0.35 ml / min, eluent: tetrahydrofuran (stabilizer BHT), column temperature: 40°C, and Mw, Mn, and Mw / Mn were calculated by conversion to standard polystyrene.

[0148] <Molecular weight of polymer>

[0149] The measurement was performed using GPC (HLC-8320 manufactured by Tosoh Corporation). After preparing a 0.2% by mass tetrahydrofuran solution of the polymer obtained in the example, 10 μl of the solution was injected into a device equipped with chromatographic columns manufactured by Tosoh Corporation (2 TSKgelSuperHZM-H (inner diameter 6.0 mm, length 15 cm) and TSKguardcolumn SuperHZ-H (inner diameter 4.6 mm, length 3.5 cm), and the measurement was performed under the conditions of a flow rate of 0.5 ml / min, eluent: tetrahydrofuran (stabilizer BHT), and column temperature: 40°C, and Mw, Mn, and Mw / Mn were calculated by conversion to standard polystyrene.

[0150] <Friction coefficient at 40℃>

[0151] The obtained polymer, YUBASE4 and MoDTC (molybdenum dialkyldithiocarbamate) were mixed for 10 minutes while heating to 65° C. in the compositions described in Tables 2 to 6 to prepare lubricating oil compositions, and the friction coefficient at 40° C. was measured using an SRV5 tester (manufactured by Optimol Instruments Pruftechnik GmbH). The measurement conditions were as follows, and the friction coefficient was evaluated 30 minutes after the start of the measurement.

[0152] ·Test method: Ball-on-disk method (ball diameter: 10 mm, material of ball and disk: SUJ2)

[0153] Test mode: reciprocating (50Hz, stroke 1mm)

[0154] Load: 200N

[0155] [Production Example 1]

[0156] (Synthesis of Co complex (cobalt chain transfer agent))

[0157] In a synthesis apparatus equipped with a stirring device, 2.00 g (8.03 mmol) of cobalt (II) acetate tetrahydrate (Wako Pure Chemical Industries, Ltd., Wako Special Grade), 3.86 g (16.1 mmol) of diphenylglyoxime (Tokyo Chemical Industry Co., Ltd., EP Grade) and 100 ml of diethyl ether previously deoxygenated by nitrogen bubbling were placed under a nitrogen atmosphere and stirred at 25°C for 2 hours.

[0158] Next, 20 ml of boron trifluoride diethyl ether complex (manufactured by Tokyo Chemical Industry Co., Ltd., EP grade) was added and stirred for further 6 hours. The obtained reaction solution was filtered, and the solid was washed with diethyl ether and dried at 100 MPa or less and 20° C. for 12 hours to obtain 5.02 g (7.93 mmol, yield 99 mass %) of a dark brown solid Co complex.

[0159] [Production Example 2]

[0160] (Synthesis of Macromonomer M1)

[0161] Into a reaction container equipped with a stirrer, a cooling tube and a thermometer, 58 parts of YUBASE4, 98 parts of Acrylic Ester SL (manufactured by Mitsubishi Chemical Corporation, trade name: Acrylic Ester SL, a mixture of an alkyl methacrylate having an alkyl group with 12 carbon atoms and an alkyl methacrylate having an alkyl group with 13 carbon atoms), 2 parts of methyl methacrylate (MMA) (manufactured by Mitsubishi Chemical Corporation, trade name: Acrylic Ester M), and 0.005 parts of the Co complex prepared in Production Example 1 were added, the liquid temperature was raised to 40°C, and nitrogen bubbling was performed for 2 hours while stirring to remove dissolved oxygen. A mixed solution consisting of 0.1 parts of YUBASE4 (2 parts) and tert-butyl peroxy-2-ethylhexanoate (manufactured by ARKEMA Yoshitomi Co., Ltd., trade name: LUPEROX 26) as a polymerization initiator was added and the liquid temperature was raised to 90°C. After stirring for 2.5 hours, a mixed solution consisting of YUBASE4 (10 parts) and LUPEROX 26 (0.7 parts) was added dropwise over 1 hour. After the addition, the temperature was raised to 105°C and maintained for 1.5 hours. Then, 20 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 52.6% by mass of the macromonomer M1. The results of GPC of the obtained macromonomer M1 are shown in Table 1.

[0162] [Production Example 3]

[0163] (Synthesis of Macromonomer M2)

[0164] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 58 parts of YUBASE4, 98 parts of Acrylic EsterSL, 2 parts of MMA and 0.005 parts of the Co complex prepared in Preparation Example 1 were added, the liquid temperature was raised to 40°C, and nitrogen was bubbled for 2 hours while stirring to remove dissolved oxygen. A mixed solution consisting of 0.1 parts of YUBASE4 (2 parts) and tert-amyl peroxy-2-ethylhexanoate (manufactured by ARKEMA Yoshitomi Co., Ltd., trade name: LUPEROX 575) as a polymerization initiator was added and the liquid temperature was raised to 90°C. After stirring for 2.5 hours, a mixed solution consisting of YUBASE4 (10 parts) and LUPEROX 26 (0.7 parts) was added dropwise over 1 hour. After the addition, the temperature was raised to 105°C and maintained for 1.5 hours, and then 20 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 52.6% by mass of the macromonomer M2. Table 1 shows the results of GPC of the obtained macromonomer M2.

[0165] [Production Example 4]

[0166] (Synthesis of Macromonomer M3)

[0167] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 58 parts of YUBASE4, 98 parts of Acrylic EsterSL, 2 parts of MMA and 0.0075 parts of the Co complex prepared in Preparation Example 1 were added, the liquid temperature was raised to 40°C, and nitrogen was bubbled for 2 hours while stirring to remove dissolved oxygen. A mixed solution consisting of 2 parts of YUBASE4 and 0.1 parts of peroxy-2-ethylhexanoic acid 1,1,3,3-tetramethylbutyl ester (manufactured by NOF Corporation, trade name: PEROCTAO) as a polymerization initiator was added and the liquid temperature was raised to 83°C. After stirring for 2.5 hours, a mixed solution consisting of 10 parts of YUBASE4 and 0.7 parts of PEROCTAO was added dropwise over 1 hour. After the addition, the temperature was raised to 95°C and maintained for 2 hours, and then 20 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 52.6% by mass of the macromonomer M3. Table 1 shows the results of GPC of the obtained macromonomer M3.

[0168] [Production Example 5]

[0169] (Synthesis of Macromonomer M4)

[0170] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 58 parts of YUBASE4, methyl methacrylate (MMA) (manufactured by Mitsubishi Chemical Corporation, trade name: Acrylic Ester M) 2 parts, stearyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester S) 98 parts, and 0.005 parts of the Co complex prepared in Preparation Example 1 were added, the liquid temperature was raised to 40°C, and nitrogen was bubbled for 2 hours while stirring to remove dissolved oxygen. A mixed solution consisting of 2 parts of YUBASE4 and 0.2 parts of tert-butyl peroxy-2-ethylhexanoate (manufactured by ARKEMA Yoshitomi Co., Ltd., trade name: LUPEROX 26) as a polymerization initiator was added, the liquid temperature was raised to 90°C, and after stirring for 2.5 hours, a mixed solution consisting of 10 parts of YUBASE4 and 0.7 parts of LUPEROX 26 was added dropwise over 1 hour. After the dropwise addition, the temperature was raised to 105°C and maintained for 1.5 hours, then 20 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 52.6% by mass of the macromonomer M4. The results of GPC of the obtained macromonomer M4 are shown in Table 1.

[0171] [Production Example 6]

[0172] (Synthesis of Macromonomer M5)

[0173] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 58 parts of YUBASE4, 100 parts of 2-ethylhexyl methacrylate and 0.003 parts of the Co complex prepared in Preparation Example 1 were added, the liquid temperature was raised to 40°C, and nitrogen was bubbled for 2 hours while stirring to remove dissolved oxygen. A mixed solution consisting of 0.1 parts of YUBASE4 (2 parts) and tert-amyl peroxy-2-ethylhexanoate (manufactured by ARKEMA Yoshitomi Co., Ltd., trade name: LUPEROX 575) as a polymerization initiator was added and the liquid temperature was raised to 90°C. After stirring for 2.5 hours, a mixed solution consisting of YUBASE4 (10 parts) and LUPEROX 575 (0.7 parts) was added dropwise over 1 hour. After the addition, the temperature was raised to 105°C and maintained for 1.5 hours, and then 20 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 52.6% by mass of the macromonomer M5. Table 1 shows the results of GPC of the obtained macromonomer M5.

[0174] <Example 1>

[0175] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 50 parts of YUBASE4, 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Production Example 2, 56 parts of n-butyl acrylate (manufactured by Mitsubishi Chemical Corporation, trade name: nBA), 18 parts of lauryl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name: LA), 1 part of 4-hydroxybutyl acrylate (manufactured by Mitsubishi Chemical Corporation, trade name: 4HBA), 0.03 parts of tert-butyl peroxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name: PERBUTYL O) as a polymerization initiator, and 0.3 parts of α-methylstyrene dimer (manufactured by NOF Corporation, trade name: NOFMER MSD) as a chain transfer agent were added, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and after maintaining for 3.5 hours, a mixed liquid consisting of YUBASE4 (42 parts) and PERBUTYL O (0.015 parts) was added dropwise over 2 hours. Furthermore, after maintaining at 85°C for 1 hour, a mixed solution consisting of YUBASE4 (30 parts) and PERBUTYL O (0.5 parts) was added dropwise over 1 hour. Then, the temperature was raised to 110°C and maintained for 1 hour, and 41.1 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the lubricating oil composition containing the friction reducer for lubricating oil obtained are shown in Table 2. In Tables 2 to 6, the polymer composition also includes the constituent units in the macromonomer (M).

[0176] <Example 2>

[0177] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4HBA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0178] <Example 3>

[0179] When a lubricating oil composition was prepared using the friction reducer for lubricating oil obtained in Example 2, MoDTC was added at the ratio described in Table 2 for evaluation. Table 2 shows the evaluation results of the obtained lubricating oil composition.

[0180] <Example 4>

[0181] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 50 parts of YUBASE4, 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3, 56 parts of nBA, 18 parts of LA, 1 part of 4HBA, 0.03 parts of PERBUTYLO, and 0.5 parts of NOFMER MSD were added, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and after maintaining for 3.5 hours, a mixed solution consisting of YUBASE4 (42 parts) and PERBUTYL O (0.015 parts) was added dropwise over 2 hours. Furthermore, after maintaining at 85°C for 1 hour, a mixed solution consisting of YUBASE4 (30 parts) and PERBUTYL O (0.5 parts) was added dropwise over 1 hour. Then, after raising the temperature to 110°C and maintaining for 1 hour, 41.1 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 2 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0182] <Example 5>

[0183] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4HBA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0184] <Example 6>

[0185] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M3 obtained in Preparation Example 4 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4HBA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0186] <Example 7>

[0187] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (44 parts), LA (30 parts), 4HBA (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.3 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0188] <Example 8>

[0189] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), LA (65 parts), 4HBA (10 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.4 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0190] <Example 9>

[0191] 30 parts of YUBASE4 and 9.5 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (69 parts), LA (22 parts), 4HBA (4 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (76.2 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0192] <Example 10>

[0193] 30 parts of YUBASE4 and 95.1 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (48 parts), 4HBA (2 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (35.6 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 2.

[0194] <Example 11>

[0195] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: HEA) (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 3 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0196] <Example 12>

[0197] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), HEA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.7 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0198] <Example 13>

[0199] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), HEA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.7 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0200] <Example 14>

[0201] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), glycerol monomethacrylate (manufactured by NOF Corporation, trade name: BLEMMER GLM) (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.4 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 3 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0202] <Example 15>

[0203] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (18 parts), BLEMMER GLM (2 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.6 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0204] <Example 16>

[0205] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction container equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (18 parts), BLEMMER GLM (2 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.6 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0206] <Example 17>

[0207] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), acrylic acid (manufactured by Mitsubishi Chemical Corporation, trade name: AA) (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.6 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 3 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0208] <Example 18>

[0209] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), AA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0210] <Example 19>

[0211] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), AA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 3.

[0212] <Example 20>

[0213] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), LA (65 parts), AA (10 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0214] <Example 21>

[0215] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), diethylacrylamide (KJ Chemicals, trade name: DEAA) (1 part), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 4 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0216] <Example 22>

[0217] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (54 parts), LA (16 parts), DEAA (5 parts), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0218] <Example 23>

[0219] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (54 parts), LA (16 parts), DEAA (5 parts), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0220] <Example 24>

[0221] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), polypropylene glycol monomethacrylate (manufactured by NOF Corporation, trade name: BLEMMER PP-800, average number of propylene oxide added moles: 13, terminal: hydroxyl group) (1 part), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 4 shows the evaluation results of the lubricating oil composition containing the obtained friction reducer for lubricating oil.

[0222] <Example 25>

[0223] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (54 parts), LA (16 parts), BLEMMER PP-800 (5 parts), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0224] <Example 26>

[0225] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (54 parts), LA (16 parts), BLEMMER PP-800 (5 parts), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 95°C and maintained for 2 hours, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0226] <Example 27>

[0227] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503) (1 part), LUPEROX 575 (0.1 parts), and NOFMERMSD (0.7 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 4 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0228] <Example 28>

[0229] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503) (3 parts), LUPEROX 575 (0.1 parts), and NOFMERMSD (0.7 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 4 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0230] <Example 29>

[0231] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 4HBA (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 4.

[0232] <Example 30>

[0233] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4HBA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0234] <Example 31>

[0235] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), HEA (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.2 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0236] <Example 32>

[0237] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), HEA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0238] <Example 33>

[0239] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M3 obtained in Preparation Example 4 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 4HBA (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0240] <Example 34>

[0241] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M3 obtained in Preparation Example 4 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4HBA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0242] <Example 35>

[0243] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M3 obtained in Preparation Example 4 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), HEA (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.2 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0244] <Example 36>

[0245] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M3 obtained in Preparation Example 4 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), HEA (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (1.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 5.

[0246] <Example 37>

[0247] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), dimethylaminoethyl acrylate (manufactured by Toagosei Co., Ltd., trade name: ARON DA) (3 parts), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 5 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0248] <Example 38>

[0249] 30 parts of YUBASE4 and 95.1 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (49 parts), polyethylene glycol monoacrylate (the number of moles of ethyleneoxy added: about 4.5, manufactured by NOF Corporation, trade name: AE-200) (1 part), LUPEROX 575 (0.1 part), and NOFMER MSD (0.9 part) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (35.6 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 5 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0250] <Example 39>

[0251] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), polyethylene glycol monoacrylate (the number of moles of ethyleneoxy added: about 10, manufactured by NOF Corporation, trade name: AE-400) (1 part), LUPEROX 575 (0.4 parts), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and then YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 5 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0252] <Example 40>

[0253] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), polypropylene glycol monoacrylate (the number of moles of propylene oxide added: about 6, manufactured by NOF Corporation, trade name: AP-400) (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. The temperature was raised to 110°C and maintained for 1 hour, and YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 6 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0254] <Example 41>

[0255] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M4 obtained in Preparation Example 5 were added to a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 4-hydroxybutyl acrylate (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0256] <Example 42>

[0257] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4-hydroxybutyl acrylate (3 parts), LUPEROX 575 (3 parts), and NOFMER MSD (4 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0258] <Example 43>

[0259] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4-hydroxybutyl acrylate (3 parts), LUPEROX 575 (1 part), and NOFMER MSD (1.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0260] <Example 44>

[0261] 40 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (55 parts), LA (17 parts), 4-hydroxybutyl acrylate (3 parts), and LUPEROX 575 (0.1 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (48.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0262] <Example 45>

[0263] 30 parts of YUBASE4 and 95.1 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (47 parts), 4-hydroxybutyl acrylate (3 parts), LUPEROX575 (0.1 parts), and NOFMER MSD (1.3 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (35.6 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0264] <Example 46>

[0265] 30 parts of YUBASE4 and 133.1 parts of the YUBASE4 solution of the macromonomer M2 obtained in Preparation Example 3 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (30 parts), nBA (27 parts), 4-hydroxybutyl acrylate (3 parts), LUPEROX 575 (1 part), and NOFMER MSD (0.9 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (20 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (44.5 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0266] <Comparative Example 1>

[0267] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 50 parts of YUBASE4, 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2, 56 parts of nBA, 19 parts of LA, 0.03 parts of PERBUTYL O and 0.05 parts of NOFMER MSD were added, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and after maintaining for 3.5 hours, a mixed solution consisting of YUBASE4 (42 parts) and PERBUTYLO (0.015 parts) was added dropwise over 2 hours. Furthermore, after maintaining at 85°C for 1 hour, a mixed solution consisting of YUBASE4 (30 parts) and PERBUTYL O (0.5 parts) was added dropwise over 1 hour. Then, after raising the temperature to 110°C and maintaining for 1 hour, 41.1 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 6 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0268] <Comparative Example 2>

[0269] In a reaction vessel equipped with a stirrer, a cooling tube and a thermometer, 72.6 parts of YUBASE4, 44 parts of nBA, 30 parts of LA, 24.5 parts of Acrylic Ester SL, 0.5 parts of MMA, 1 part of 4HBA, 0.03 parts of PERBUTYL O and 0.15 parts of NOFMER MSD were added, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and after maintaining for 3.5 hours, a mixed solution consisting of YUBASE4 (42 parts) and PERBUTYL O (0.015 parts) was added dropwise over 2 hours. Furthermore, after maintaining at 85°C for 1 hour, a mixed solution consisting of YUBASE4 (60 parts) and PEROCTAO (0.5 parts) was added dropwise over 1 hour. Then, after raising the temperature to 110°C and maintaining for 1 hour, 11.1 parts of YUBASE4 were added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 6 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0270] <Comparative Example 3>

[0271] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M1 obtained in Preparation Example 2 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen was bubbled while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 2-methoxyethyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name: 2-MTA) (1 part), LUPEROX 575 (1 part), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. Table 6 shows the evaluation results of the obtained lubricating oil composition containing the friction reducing agent for lubricating oil.

[0272] <Comparative Example 4>

[0273] 30 parts of YUBASE4 and 47.6 parts of the YUBASE4 solution of the macromonomer M5 obtained in Preparation Example 6 were added to a reaction vessel equipped with a stirrer, a cooling tube, and a thermometer, and nitrogen bubbling was performed while stirring to remove dissolved oxygen. The liquid temperature was raised to 85°C, and a mixed solution consisting of YUBASE4 (25 parts), nBA (56 parts), LA (18 parts), 4-hydroxybutyl acrylate (1 part), LUPEROX 575 (0.1 parts), and NOFMER MSD (0.5 parts) was added dropwise over 4 hours. After maintaining at 85°C for 1 hour, a mixed solution of YUBASE4 (50 parts) and LUPEROX 575 (0.5 parts) was added dropwise over 1.5 hours. After the temperature was raised to 110°C and maintained for 1 hour, YUBASE4 (58.1 parts) was added and cooled to obtain a YUBASE4 solution containing 35% by mass of a polymer. The evaluation results of the obtained lubricating oil composition containing a friction reducer for lubricating oil are shown in Table 6.

[0274] Since the polymer of Comparative Example 1 does not contain a constituent unit from the component (b), the friction coefficient becomes high. In addition, since Comparative Example 2 does not have a side chain polymer structure, the friction coefficient becomes high. Since the polymer of Comparative Example 3 contains a constituent unit having an alkoxyalkyl group as a polar group, but does not contain a constituent unit from the component (b), the friction coefficient becomes high in the same manner as in Comparative Example 1. Since the side chain polymer structure of Comparative Example 4 does not contain a constituent unit from the component (a), the friction coefficient becomes high.

[0275] [Table 1]

[0276]

[0277] [Table 2]

[0278]

[0279] [Table 3]

[0280]

[0281] [Table 4]

[0282]

[0283] [Table 5]

[0284]

[0285] [Table 6]

[0286]

[0287] The abbreviations in Tables 1 to 6 are as follows.

[0288] SLMA: A mixture of an alkyl methacrylate having an alkyl group with 12 carbon atoms and an alkyl methacrylate having an alkyl group with 13 carbon atoms (manufactured by Mitsubishi Chemical Corporation, trade name: Acrylic Ester SL)

[0289] ·MMA: Methyl methacrylate (manufactured by Mitsubishi Chemical Corporation, trade name: Acrylic Ester M)

[0290] ·SMA: Stearyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name: Light Ester S)

[0291] · EHMA: 2-ethylhexyl methacrylate (manufactured by Mitsubishi Chemical Corporation, trade name "Acrylic Ester EH")

[0292] M1: macromonomer synthesized in Preparation Example 2

[0293] M2: macromonomer synthesized in Preparation Example 3

[0294] M3: macromonomer synthesized in Preparation Example 4

[0295] M4: macromonomer synthesized in Preparation Example 5

[0296] M5: macromonomer synthesized in Preparation Example 6

[0297] LA: Lauryl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: LA)

[0298] 4HBA: 4-Hydroxybutyl acrylate (Mitsubishi Chemical Corporation, trade name: 4HBA)

[0299] ·HEA: Hydroxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: HEA)

[0300] ·GLM: Glyceryl monomethacrylate (manufactured by NOF Corporation, trade name: BLEMMER GLM)

[0301] AA: Acrylic acid (manufactured by Mitsubishi Chemical Corporation, trade name: acrylic acid)

[0302] ·DEAA: Diethylacrylamide (manufactured by KJ Chemicals, trade name: DEAA)

[0303] PP800: Polypropylene glycol monomethacrylate (manufactured by NOF Corporation, trade name: BLEMMER PP-800, average number of moles of propylene oxide added: 13, terminal: hydroxyl group)

[0304] KBM503: 3-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM503)

[0305] ·ARON DA: dimethylaminoethyl acrylate (manufactured by Toagosei Co., Ltd., trade name: ARON DA)

[0306] AE-200: Polyethylene glycol monoacrylate (number of moles of ethyleneoxy added: about 4.5, manufactured by NOF Corporation, trade name: BLEMMER AE-200)

[0307] AE-400: Polyethylene glycol monoacrylate (number of moles of ethyleneoxy added: about 10, manufactured by NOF Corporation, trade name: BLEMMER AE-400)

[0308] AP-400: Polypropylene glycol monoacrylate (number of moles of propylene oxide added: about 6, manufactured by NOF Corporation, trade name: BLEMMER AP-400)

[0309] nBA: n-butyl acrylate (manufactured by Mitsubishi Chemical Corporation, trade name: butyl acrylate)

[0310] ·2-MTA: 2-methoxyethyl acrylate (manufactured by Osaka Organic Chemical Co., Ltd., trade name: 2-MTA)

[0311] Industrial Applicability

[0312] According to the polymer of the present invention, a lubricating oil additive, a friction reducer for lubricating oil, and a lubricating oil composition having a high friction reducing effect can be provided.

Claims

1. A polymer having a main chain polymer structure and a side chain polymer structure, The side chain polymer structure includes a constituent unit derived from an alkyl (meth)acrylate (a) having an alkyl group with 11 to 30 carbon atoms, At least one of the main chain polymer structure and the side chain polymer structure contains a constituent unit derived from a (meth)acrylate (b) represented by the following general formula (1), In the formula, R 1 is a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or an organic group containing a polar group, wherein, The organic group containing a polar group does not include an alkoxyalkyl group.

2. The polymer according to claim 1, wherein The polar group of the (meth)acrylate (b) is a hydroxyl group, a carboxyl group, an amino group or an amide group.

3. The polymer according to claim 1, wherein The polar group of the (meth)acrylate (b) is a hydroxyl group.

4. The polymer according to claim 1, wherein The compound further contains a structural unit derived from an alkyl (meth)acrylate (c) having an alkyl group having 1 to 10 carbon atoms.

5. The polymer according to claim 1, wherein The main chain polymer structure includes a structural unit derived from an alkyl (meth)acrylate (a) having an alkyl group with 11 to 30 carbon atoms.

6. The polymer according to claim 1, wherein The main chain polymer structure includes constituent units derived from a vinyl radical polymerizable monomer (m1), and at least a part of the constituent units derived from the vinyl radical polymerizable monomer (m1) are constituent units derived from the (meth)acrylate (b).

7. The polymer according to claim 6, wherein The side chain polymer structure includes a constitutional unit derived from a macromonomer (M).

8. The polymer according to claim 7, wherein The macromonomer (M) includes a structural unit derived from the (meth)acrylic acid alkyl ester (a) having an alkyl group having 11 to 30 carbon atoms.

9. The polymer according to claim 7, wherein The macromonomer (M) has the structure of the following formula (2), In the formula, X 1 ~X n－1 Each independently represents a hydrogen atom, a methyl group or CH2OH, Y 1 ~Y n Each independently represents a vinyl group bonded to the vinyl radical polymerizable monomer (m2) as a monomer constituent unit of the macromonomer (M), except X 1 ~X n－1 In the case of a substituent other than , Z represents a terminal group, and n represents an integer of 2 to 10,000.

10. A lubricating oil additive comprising the polymer according to any one of claims 1 to 9.

11. A friction reducer for lubricating oil, comprising the polymer according to any one of claims 1 to 9 and a solvent.

12. A lubricating oil composition comprising the friction reducer for lubricating oil according to claim 11.

13. The friction reducer for lubricating oil according to claim 11, wherein The solvent is a base oil.

14. A lubricating oil composition comprising the friction reducer for lubricating oil according to claim 13.

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