Anti-foaming agent, lubricating oil composition containing Anti-foaming agent, and machine using lubricating oil composition

Abstract

Provided is an anti-foaming agent which exhibits excellent anti-foaming properties even in a high temperature environment.　The anti-foaming agent contains a polymer containing, as polymer components, at least a polymerizable monomer (A) that is: a polymerizable monomer (a1) which has a polysiloxane structure represented by -[OSi(R)2]x- (R moieties are each independently an alkyl group having 1-6 carbon atoms, and x is the number of repetitions) and has two or more polymerizable unsaturated groups; and / or a polymerizable monomer (a2) which has a functional group represented by -Si[OSi(R)3]n[R']3-n (n is an integer between 1 and 3, R moieties are each independently an alkyl group having 1-6 carbon atoms, and R' moieties are each independently an alkyl group having 1-6 carbon atoms) and which has two or more polymerizable unsaturated groups.

Description

Antifoaming agent, lubricating oil composition containing antifoaming agent, and machine using the lubricating oil composition

[0001] The present invention relates to an antifoaming agent, a lubricating oil composition containing the antifoaming agent, and a machine using the lubricating oil composition.

[0002] Reducing carbon dioxide emissions has become an important theme in the industrial world in recent years. Carbon dioxide emissions from transportation equipment, including automobiles, account for nearly 20% of the total, and as one measure to reduce this, countries around the world have announced policies to switch from gasoline-powered vehicles to electric vehicles (EVs).

[0003] The most important issue for EVs is improving fuel efficiency (electricity cost), and to that end, research is being conducted at a rapid pace to reduce the size of the vehicle body and improve the efficiency of the drivetrain. One of the issues in improving the efficiency of the drivetrain is foaming of lubricating oil. Lubricating oils are becoming less viscous to reduce frictional resistance, but this lower viscosity makes them more prone to foaming.

[0004] When high-load operation or high-speed driving is performed continuously, foaming increases in the low-viscosity lubricating oil, which can cause problems such as reduced lubrication performance and cooling efficiency; wear and seizure due to rupture of the oil film at friction points; and accelerated deterioration of the lubricating oil due to increased oil temperature.

[0005] For this reason, lubricating oils with high defoaming properties are required to suppress foaming from the initial stage of operation over a long period of time, and lubricating oils contain defoamers to prevent foaming. Polysiloxane-based defoamers are known as such defoamers, and various polysiloxane-based defoamers have been proposed (for example, Patent Document 1).

[0006] JP 2017-039924 A

[0007] Conventional polysiloxane-based defoaming agents have the problem that their defoaming properties decrease significantly as the temperature rises. For example, there has been a problem in that sufficient defoaming properties cannot be obtained in automotive applications where defoaming properties at high temperatures are required.

[0008] The problem to be solved by the present invention is to provide an antifoaming agent that exhibits excellent antifoaming properties even in a high-temperature environment. Another problem to be solved by the present invention is to provide a lubricating oil composition that can exhibit excellent lubricating performance even in a high-temperature environment.

[0009] As a result of intensive investigations to solve the above problems, the present inventors have found that a polymer containing, as at least a polymerization component, a polymerizable monomer having a specific silicone functional group and two or more polymerizable unsaturated groups is a defoaming agent that exhibits excellent defoaming properties even in a high-temperature environment, and have completed the present invention.

[0010] That is, the present invention relates to the following defoaming agent etc.: [1] -[OSi(R) ２ ] ｘ -(each R is independently an alkyl group having 1 to 6 carbon atoms, and x is the number of repetitions), and a polymerizable monomer (a1) having two or more polymerizable unsaturated groups and / or -Si[OSi(R) ３ ] ｎ [R'] ３－ｎ (n is an integer of 1 to 3. Each R is independently an alkyl group having 1 to 6 carbon atoms. Each R' is independently an alkyl group having 1 to 6 carbon atoms), and the polymerizable monomer (A) is a polymerizable monomer (a2) having two or more polymerizable unsaturated groups. [2] The defoaming agent according to [1], wherein the polymerizable monomer (A) is a compound represented by the following general formula (A-1) and / or a compound represented by the following general formula (A-2): (In the general formula (A-1) and the general formula (A-2), R １１ are each independently an alkyl group having 1 to 6 carbon atoms; R １２ are each independently an alkyl group having 1 to 6 carbon atoms; R １３ are each independently a hydrogen atom or a methyl group, R １４ is an alkyl group having 1 to 12 carbon atoms, R １５ are each independently an alkyl group having 1 to 6 carbon atoms or —OSi(R １６ ) ３A group represented by R １６ each independently represents an alkyl group having 1 to 6 carbon atoms; x represents the number of repetitions; y represents an integer of 1 or greater; z1 and z2 each independently represent an integer of 1 or greater; z3 represents an integer of 2 or greater; L １１ is a z1+1 valent organic group which may have an ether bond, and L １２ is a z2+1 valent organic group which may have an ether bond, and L １３ is an organic group having a valence of z+y and which may have an ether bond, １４ is a divalent organic group which may have an ether bond or a single bond.) [3] A defoaming agent containing a polymer having, as at least a polymerization component, a polymerizable monomer (A') which is a compound represented by the following general formula (A-3): (In the general formula (A-3), R １３ are each independently a hydrogen atom or a methyl group, R ５１ are each independently an alkyl group having 1 to 6 carbon atoms; １５ represents a divalent organic group which may have an ether bond, and a represents a repeating unit and is an integer of 0 to 3. [4] A defoaming agent containing a polymer having, as at least a polymerization component, a polymerizable monomer (A″), which is a compound represented by the following general formula (A-4): (In the general formula (A-4), R １３ are each independently a hydrogen atom or a methyl group, R ５２ are each independently an alkyl group having 1 to 6 carbon atoms; １６ each independently represents a divalent organic group which may have an ether bond. [5] A defoaming agent containing a polymer having, as at least a polymerization component, a polymerizable monomer (A′″), which is a compound represented by the following general formula (A-5): (In the general formula (A-5), R １３ are each independently a hydrogen atom or a methyl group, R ５３ are each independently an alkyl group having 1 to 6 carbon atoms; R ５４ are each independently an alkyl group having 1 to 6 carbon atoms;１７ are each independently a divalent organic group which may have an ether bond, t is a repeating unit which is each independently an integer of 1 to 100, and u is a repeating unit which is an integer of 1 to 10. [6] A defoaming agent containing a polymer having, as at least a polymerization component, a polymerizable monomer (A''''), which is a compound represented by the following general formula (A-6): (In the general formula (A-6), R １３ are each independently a hydrogen atom or a methyl group, R ５５ are each independently an alkyl group having 1 to 6 carbon atoms; １８ are each independently a divalent organic group which may have an ether bond, and v is a repeating unit which is each independently an integer of 1 to 100. [7] The defoaming agent according to any one of [1] to [6], wherein the contents of the polymerizable monomer (A), the polymerizable monomer (A'), the polymerizable monomer (A"), the polymerizable monomer (A'"), and the polymerizable monomer (A"") in the polymerization components are in the range of 5 to 75 mass%. [8] The defoaming agent according to any one of [1] to [7], wherein the polymerization components further contain a polymerizable monomer (B) having one or more groups selected from an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 18 carbon atoms, a group containing a polyoxyalkylene chain, and a group containing a polyester chain, and having one polymerizable unsaturated group. [9] The defoaming agent according to [8], wherein the polymerizable monomer (B) is one or more selected from the group consisting of compounds represented by the following (B-1) to (B-10): (In the general formulae (B-1), (B-2), (B-3), (B-4), (B-5), (B-6), (B-7), (B-8), (B-9) and (B-10), R ２１ is a hydrogen atom or a methyl group, R ２２ is an alkyl group having 1 to 18 carbon atoms; R ２３ is a hydrogen atom or a methyl group, R ２４ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms; R ２５ is a hydrogen atom or a methyl group, R ２６is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond, and R ２７ is a hydrogen atom or a methyl group, R ２８ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond, and R ２９ is a hydrogen atom or a methyl group, R ３０ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, R ３１ ~R ３５ are each independently a hydrogen atom or a methyl group, and L １９ and L ２０ each independently represents a divalent organic group which may have an ether bond or a single bond, ２１ and L ２２ each independently represents a divalent organic group which may have an ether bond or a single bond, ２３ represents an r1+1 valent organic group which may have an ether bond or a single bond, and L ２４ is an r2+r3 valent organic group which may have an ether bond and / or an ester bond, and L ２５ is an r4+1-valent organic group which may have an ether bond, and L ２６ represents a single bond or an organic group having a valence of r5+1, which may have an ether bond; ２７is a single bond or an organic group which may have an ether bond, m represents the number of repetitions, and the number average value of m is in the range of 1 to 200, p is an integer in the range of 1 to 10, q represents the number of repetitions, and the number average value of q is in the range of 1 to 100, l is an integer in the range of 0 to 5, r2 and r3 represent the number of repetitions, and are integers in the range of 1 to 3, and r1, r4, r5, and r6 represent the number of repetitions, and are 2 or 3.)

[10] The defoaming agent according to [9], wherein the polymerizable monomer (B) comprises a compound represented by any one of general formulas (B-2), (B-7), and (B-8).

[11] The defoaming agent according to any one of [8] to

[10] , wherein the content of the polymerizable monomer (B) in the polymerization components is in the range of 5 to 75 mass%.

[12] The defoaming agent according to any one of [1] to

[11] , wherein the polymerization components further contain a polymerizable monomer (C) having two or more polymerizable unsaturated groups other than the polymerizable monomer (A), the polymerizable monomer (A'), the polymerizable monomer (A"), the polymerizable monomer (A'"), and the polymerizable monomer (A"").

[13] The defoaming agent according to

[11] , wherein the polymerizable monomer (C) is a compound represented by the following general formula (C-1): (In the general formula (C-1), R ３６ is a hydrogen atom or a methyl group; r is an integer of 2 or more; L ３１ is an organic group which may have an r-valent ether bond.)

[14] The defoaming agent according to

[12] or

[13] , wherein the content of the polymerizable monomer (C) in the polymerization components is in the range of 5 to 70 mass%.

[15] The defoaming agent according to any one of [1] to

[14] , wherein the weight-average molecular weight of the polymer is in the range of 2,000 to 200,000.

[16] The defoaming agent according to [1], which contains a polymerizable monomer (D) in which the number of polymerizable unsaturated groups in the polymerizable monomer (A) is one.

[17] The defoaming agent according to

[16] , wherein the polymerizable monomer (D) is a compound represented by the following general formula (D-1): (In the general formula (D-1), R ４１ are each independently an alkyl group having 1 to 6 carbon atoms or —OSi(R ４４ ) ３ A group represented by R ４４are each independently an alkyl group having 1 to 3 carbon atoms, ４２ are each independently an alkyl group having 1 to 6 carbon atoms; R ４３ is an alkyl group having 1 to 12 carbon atoms, R ４５ is a hydrogen atom or a methyl group, and L ４１ is a divalent organic group which may have an ether bond, and s represents the number of repetitions.)

[18] A lubricating oil composition containing a lubricating base oil and the antifoaming agent according to any one of [1] to

[17] .

[19] The lubricating oil composition according to

[18] , which is used to lubricate the driving parts of a machine equipped with an internal combustion engine or an electric motor.

[20] The lubricating oil composition according to

[18] , which is used to lubricate the driving parts of a vehicle equipped with an internal combustion engine or an electric motor.

[21] A machine using the lubricating oil composition according to any one of

[18] to

[20] in its driving parts.

[0011] The present invention can provide an antifoaming agent that exhibits excellent antifoaming properties even in a high-temperature environment, and a lubricating oil composition that can exhibit excellent lubricating performance even in a high-temperature environment.

[0012] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and appropriate modifications can be made within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources. In this specification, "(meth)acrylate" refers to either or both of acrylate and methacrylate.

[0013] [Antifoaming agent] The antifoaming agent of the present invention is —[OSi(R) ２ ] ｘ -(each R is independently an alkyl group having 1 to 6 carbon atoms, and x is the number of repetitions), and a polymerizable monomer (a1) having two or more polymerizable unsaturated groups and / or -Si[OSi(R) ３ ] ｎ [R'] ３－ｎ(n is an integer of 1 to 3. Each R is independently an alkyl group having 1 to 6 carbon atoms. Each R' is independently an alkyl group having 1 to 6 carbon atoms), and the polymerizable monomer (A) is a polymerizable monomer (a2) having two or more polymerizable unsaturated groups. Here, the term "polymerizable monomer" means a component that constitutes the polymer, and does not include solvents, polymerization initiators, etc. that do not constitute the polymer.

[0014] In the present invention, the term "polymerizable monomer" means a compound having a polymerizable unsaturated group, and examples of the polymerizable unsaturated group contained in the polymerizable monomer (A) include a (meth)acryloyl group, a (meth)acryloyloxy group, a (meth)acryloylamide group, a vinyl ether group, an allyl group, a styryl group, a (meth)acryloylamino group, and a maleimide group.

[0015] A polymer having at least the polymerizable monomer (A) contained in the defoaming agent of the present invention as a polymerization component may be referred to as the “polymer of the present invention.” Each component constituting the polymer of the present invention will be explained below.

[0016] The —[OSi(R) ２ ] ｘ The polysiloxane structure represented by - is preferably a polydimethylsiloxane structure. ３ ] ｎ [R'] ３－ｎ The functional group represented by is preferably —Si[OSi(R) ３ ] ３ is a functional group represented by the formula: ３ ) ３ ] ３ is.

[0017] The polymerizable monomer (A) is preferably a compound represented by the following general formula (A-1) and / or a compound represented by the following general formula (A-2).

[0018] (In the general formula (A-1) and the general formula (A-2), R １１are each independently an alkyl group having 1 to 6 carbon atoms; R １２ are each independently an alkyl group having 1 to 6 carbon atoms; R １３ are each independently a hydrogen atom or a methyl group, R １４ is an alkyl group having 1 to 12 carbon atoms, R １５ are each independently an alkyl group having 1 to 6 carbon atoms or —OSi(R １６ ) ３ A group represented by R １６ each independently represents an alkyl group having 1 to 6 carbon atoms; x represents the number of repetitions; y represents an integer of 1 or greater; z1 and z2 each independently represent an integer of 1 or greater; z3 represents an integer of 2 or greater; L １１ is a z1+1 valent organic group which may have an ether bond, and L １２ is a z2+1 valent organic group which may have an ether bond, and L １３ is an organic group having a valence of z+y and which may have an ether bond, １４ is a divalent organic group which may have an ether bond. P is a polymerizable group represented by general formula (P-1), a polymerizable group represented by general formula (P-2), or a polymerizable group represented by general formula (P-3). In general formula (P-1), general formula (P-2), and general formula (P-3), R １３ is a hydrogen atom or a methyl group. １７ is a hydrogen atom or an organic group. * is L １１ or L １４ is the bond that bonds with

[0019] The polymerizable monomer (A) is more preferably a compound represented by the general formula (A-1) and / or a compound represented by the general formula (A-2), in which P is a polymerizable group represented by the general formula (P-1), and is represented by the following general formula:

[0020]

[0021] R １１ , R １２ , R １５ and R １６The alkyl group having 1 to 6 carbon atoms in R is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. １４ The alkyl group having 1 to 12 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms.

[0022] R １７ Examples of the organic group include alkyl groups having 1 to 18 carbon atoms. １７ Examples of the alkylene group having 1 to 18 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, an n-nonyl group, an n-decyl group, an n-dodecyl group, an isopropyl group, a 2-methylpropyl group, a 2-methylhexyl group, and a tetramethylethyl group.

[0023] The number of repetitions of x may be, for example, an integer of 1 or more. The number average of x is, for example, in the range of 1 to 150, preferably in the range of 1 to 75, more preferably in the range of 1 to 50, and even more preferably in the range of 1 to 20. The number average of x can be confirmed by measuring the number average molecular weight of the polymerizable monomer (A) by the method described in the examples.

[0024] z1 is an integer of 1 or more, preferably an integer in the range of 1 to 4, more preferably an integer of 1 or 2, and even more preferably 1.

[0025] L １１ Regarding the z1+1 valent organic group which may have an ether bond, for example, L １１ When is a divalent organic group (z1=1), the divalent organic group is preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0026] L １１Examples of the alkylene group having 1 to 50 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, an n-decylene group, an n-dodecylene group, an isopropylene group, a 2-methylpropylene group, a 2-methylhexylene group, and a tetramethylethylene group.

[0027] L １１ The alkylene group having 1 to 50 carbon atoms is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably a methylene group, an ethylene group, an n-propylene group, or an isopropylene group.

[0028] L １１ The alkyleneoxy group having 1 to 50 carbon atoms may be, for example, one or more —CH ２ - is a group in which - is substituted with -O-. １１ The alkyleneoxy group having 1 to 50 carbon atoms is preferably an alkyleneoxy group having 1 to 15 carbon atoms, more preferably an alkyleneoxy group having 1 to 8 carbon atoms, and even more preferably a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, a propyleneoxyethylene group, an oxytrimethylene group, a butyleneoxy group, an oxytetramethylene group, a pentyleneoxy group, a heptyleneoxy group, or an octyleneoxy group.

[0029] L １１ When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, these divalent organic groups are -CH ２ A part of the - may be replaced by a carbonyl group (-C(=O)-), a phenylene group, an amide bond, a sulfide bond (-S-) or a urethane bond (-NHC(=O)-).

[0030] L １１ When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, a carbon atom of these groups may further be substituted with a substituent such as a hydroxyl group.

[0031] L１１ When the z1+1 valent organic group is a trivalent or higher valent organic group, the trivalent or higher valent organic group is, for example, an organic group in which a hydrogen atom bonded to a carbon atom of the divalent organic group described above is replaced with a bond so as to have a corresponding valence.

[0032] z2 is an integer of 1 or more, preferably an integer in the range of 1 to 4, more preferably an integer of 1 or 2, and even more preferably 1.

[0033] L １２ The z2+1 valent organic group is L １１ is the same as the z1+1 valent organic group.

[0034] y is an integer of 1 or more, preferably an integer in the range of 1 to 4, more preferably an integer in the range of 1 to 3, and even more preferably 1 or 2.

[0035] z3 is an integer of 2 or more, preferably an integer in the range of 2 to 6, more preferably an integer of 2 or 3, and even more preferably 2.

[0036] L １３ The organic group having a valence of z3+y is L １１ z1+1 valent organic group L １３ For example, L １３ When L is a trivalent organic group, １３ The trivalent organic group is L １１ It is preferable that the trivalent organic group is the same as the above trivalent organic group.

[0037] L １４ The divalent organic group is L １１ is the same as the divalent organic group.

[0038] The defoaming agent of the present invention may have an embodiment containing not only the above-mentioned polymerizable monomer (A) but also the following polymerizable monomer (A'), polymerizable monomer (A"), polymerizable monomer (A""), and polymer having polymerizable monomer (A"") as at least a polymerization component. These embodiments will be described below.

[0039] The polymerizable monomer (A') is a compound represented by the following general formula (A-3) having a cyclic siloxane structure and 3 to 6 (meth)acrylate groups branched therefrom.

[0040] (In the general formula (A-3), R １３ are each independently a hydrogen atom or a methyl group, R ５１ are each independently an alkyl group having 1 to 6 carbon atoms; １５ represents a divalent organic group which may have an ether bond, and a represents a repeating unit and is an integer of 0 to 3.

[0041] R ５１ is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. a is preferably 1 or 2, more preferably 1. When a is 0, adjacent Si and O are bonded to form a cyclic siloxane compound having three (meth)acrylate groups. As a increases to 2 and 3, the -Si-O- in the cyclic siloxane structure also increases; when a is 2, the compound has five (meth)acrylate groups, and when a is 3, the compound has six (meth)acrylate groups.

[0042] L １５ The divalent organic group is the same as the above-mentioned L １１ and preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0043] Specific examples of the compound represented by general formula (A-3) include compounds represented by the following formulae (A-3-1), (A-3-2), (A-3-3), (A-3-4), (A-3-5), and (A-3-6).

[0044]

[0045] The polymerizable monomer (A″) is a linear siloxane compound having (meth)acrylate groups at both ends, represented by the following general formula (A-4).

[0046] (In the general formula (A-4), R １３are each independently a hydrogen atom or a methyl group, R ５２ are each independently an alkyl group having 1 to 6 carbon atoms; １６ are each independently a divalent organic group which may have an ether bond.

[0047] R ５２ is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. １６ represents L in general formula (A-3). １５ and preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0048] Specific examples of the compound represented by the general formula (A-4) include compounds represented by the following formulae (A-4-1) and (A-4-2).

[0049]

[0050] The polymerizable monomer (A''') is a compound having one or more (meth)acrylate groups and a branched siloxane structure, represented by the following general formula (A-5).

[0051] (In the general formula (A-5), R １３ are each independently a hydrogen atom or a methyl group, R ５３ are each independently an alkyl group having 1 to 6 carbon atoms; R ５４ are each independently an alkyl group having 1 to 6 carbon atoms; １７ are each independently a divalent organic group which may have an ether bond, t is a repeating unit and each independently an integer of 1 to 100, and u is a repeating unit and an integer of 1 to 10.

[0052] R ５３ and R ５４is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. The number average of t is, for example, in the range of 0 to 150, preferably in the range of 0 to 75, more preferably in the range of 0 to 50, and even more preferably in the range of 0 to 20. u is preferably 1 to 4, more preferably 1 to 2. L in general formula (A-5) １７ L in general formula (A-3) １５ and preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0053] Specific examples of the compound represented by general formula (A-5) include compounds represented by formulae (A7), (A8), and (A9) described in Synthesis Example 7 below, and compounds represented by the following formulae (A7'), (A8'), and (A9') (in the formulae, t1, t2, and t3 are each independently an integer of 0 to 7).

[0054]

[0055] The polymerizable monomer (A'''') is a compound represented by the following general formula (A-6).

[0056] (In the general formula (A-6), R １３ are each independently a hydrogen atom or a methyl group, R ５５ are each independently an alkyl group having 1 to 6 carbon atoms; １８ are each independently a divalent organic group which may have an ether bond, and v is a repeating unit and is each independently an integer of 1 to 100.

[0057] R ５５ is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. The number average of v is, for example, in the range of 1 to 150, preferably in the range of 1 to 75, more preferably in the range of 1 to 50, and even more preferably in the range of 1 to 20. １８ L in general formula (A-3) １５ and preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0058] Specific examples of the compound represented by the general formula (A-6) include compounds represented by formula (A10) described in Synthesis Example 8 below and the following formula (A10').

[0059]

[0060] The polymerizable monomer (A) can be produced by a known method. For example, the polymerizable monomer (A) is a —[OSi(R) ２ ] ｘ - and / or -Si[OSi(R) ３ ] ｎ [R'] ３－ｎ and two or more hydroxyl groups, with a compound having an isocyanate group and a polymerizable unsaturated group. ２ ] ｘ - and / or -Si[OSi(R) ３ ] ｎ [R'] ３－ｎ and a polymerizable unsaturated group, with an alcohol having a mercapto group to produce a precursor, and then reacting the precursor with a compound having an isocyanate group and two or more polymerizable unsaturated groups. The polymerizable monomer (A'), polymerizable monomer (A"), polymerizable monomer (A'"), and polymerizable monomer (A"") can also be produced by the same method as for polymerizable monomer (A).

[0061] In the polymer of the present invention, the lower limit of the content of the polymerizable monomer (A) is, for example, 3% by mass or more, 5% by mass or more, 10% by mass or more, 20% by mass or more, 25% by mass or more, or 30% by mass or more, based on the total amount of polymerization components of the polymer. The upper limit of the content of the polymerizable monomer (A) is, for example, 90% by mass or less, 80% by mass or less, 75% by mass or less, 70% by mass or less, or 60% by mass or less, based on the total amount of polymerization components of the polymer. The combination of the upper and lower limits of the content of the polymerizable monomer (A) can be, for example, in the range of 3% by mass to 90% by mass of the total amount of polymerization components of the polymer, preferably 5% by mass to 75% by mass, and more preferably 30% by mass to 70% by mass. The content of the polymerizable monomer (A) can be adjusted by the raw material charge ratio of the polymerizable monomer (A) when producing the polymer of the present invention. The polymerizable monomer (A'), polymerizable monomer (A"), polymerizable monomer (A""), and polymerizable monomer (A"") are also in the same ratio as that of the polymerizable monomer (A).

[0062] The polymerization component of the polymer of the present invention preferably further contains a polymerizable monomer (B) having one or more groups selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 18 carbon atoms, a group containing a polyoxyalkylene chain, and a group containing a polyester chain, and having one polymerizable unsaturated group. By further containing the polymerizable monomer (B) as a polymerization component, when the antifoaming agent of the present invention is added to a lubricating oil composition, high compatibility of the antifoaming agent with the lubricating base oil can be ensured.

[0063] The alkyl group having 1 to 18 carbon atoms contained in the polymerizable monomer (B) may be any of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group, and specific examples thereof include a methyl group, an ethyl group, a normal propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-hexyl group, a cyclohexyl group, an n-octyl group, a hexadecyl group, etc. The alkyl group having 1 to 18 carbon atoms contained in the polymerizable monomer (B) is preferably an alkyl group having 1 to 6 carbon atoms.

[0064] Examples of the aromatic group having 6 to 18 carbon atoms contained in the polymerizable monomer (B) include a phenyl group, a naphthyl group, an anthracen-1-yl group, and a phenanthrene-1-yl group.

[0065] The group containing a (poly)oxyalkylene chain contained in the polymerizable monomer (B) is a monovalent group containing a repeating oxyalkylene moiety or a divalent linking group containing a repeating oxyalkylene moiety.

[0066] The group containing a polyester chain contained in the polymerizable monomer (B) is a monovalent group containing a repeating ester bond moiety or a divalent linking group containing a repeating ester bond moiety.

[0067] The alkyl group having 1 to 18 carbon atoms contained in the polymerizable monomer (B) may further have a substituent, and examples of the substituent include a hydroxyl group, an aryl group, etc. The aromatic group having 6 to 18 carbon atoms contained in the polymerizable monomer (B) may further have a substituent, and examples of the substituent include a hydroxyl group, an alkyl group, etc.

[0068] Examples of the polymerizable monomer (B) having an alkyl group having 1 to 18 carbon atoms and in which the polymerizable unsaturated group is a (meth)acryloyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, s-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, and methyl (meth)acrylate. (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and other alkyl esters of (meth)acrylic acid having 1 to 18 carbon atoms; and bridged cyclic alkyl esters of (meth)acrylic acid having 1 to 18 carbon atoms, such as dicyclopentanyloxylethyl (meth)acrylate, isobornyloxylethyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dimethyladamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyl (meth)acrylate. In this application, "(meth)acrylate" refers to both methacrylate and acrylate.

[0069] Examples of the polymerizable monomer (B) having a phenylalkyl group having 7 to 18 carbon atoms or a phenoxyalkyl group having 7 to 18 carbon atoms and in which the polymerizable unsaturated group is a (meth)acryloyl group include benzyl (meth)acrylate, phenoxymethyl (meth)acrylate, and 2-phenoxyethyl (meth)acrylate.

[0070] Examples of the polymerizable monomer (B) having an alkyl group having 1 to 18 carbon atoms and in which the polymerizable unsaturated group is a vinyl ether group include alkyl vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, n-pentyl vinyl ether, n-hexyl vinyl ether, n-octyl vinyl ether, n-dodecyl vinyl ether, 2-ethylhexyl vinyl ether, and cyclohexyl vinyl ether; and cycloalkyl vinyl ethers.

[0071] Examples of the polymerizable monomer (B) having an aromatic group having 6 to 18 carbon atoms include styrene, α-methylstyrene, p-methylstyrene, and p-methoxystyrene.

[0072] Examples of the polymerizable monomer (B) having an alkyl group having 1 to 18 carbon atoms and in which the polymerizable unsaturated group is a (meth)acryloylamino group include N,N-dimethylacrylamide, N,N-diethylacrylamide, N-isopropylacrylamide, diacetoneacrylamide, and acroylmorpholine.

[0073] Examples of the polymerizable monomer (B) having an alkyl group having 1 to 18 carbon atoms and in which the polymerizable unsaturated group is a maleimide group include methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, and cyclohexylmaleimide.

[0074] Examples of the polymerizable monomer (B) having a group containing a polyoxyalkylene chain and in which the polymerizable unsaturated group is a (meth)acryloyl group include polypropylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polytrimethylene glycol mono(meth)acrylate, polytetramethylene glycol mono(meth)acrylate, poly(ethylene glycol.propylene glycol) mono(meth)acrylate, polyethylene glycol.polypropylene glycol mono(meth)acrylate, poly(ethylene glycol.tetramethylene glycol) mono(meth)acrylate, polyethylene glycol.polytetramethylene glycol mono(meth)acrylate, poly(propylene glycol.tetramethylene glycol) mono(meth)acrylate, polypropylene glycol.polytetramethylene glycol mono(meth)acrylate, poly(propylene glycol.1,2-butylene glycol) mono(meth)acrylate, polypropylene glycol.poly1,2-butylene glycol mono(meth)acrylate, Poly(ethylene glycol·1,2-butylene glycol) mono(meth)acrylate, polyethylene glycol·poly 1,2-butylene glycol mono(meth)acrylate, poly(tetraethylene glycol·1,2-butylene glycol) mono(meth)acrylate, polytetraethylene glycol·poly 1,2-butylene glycol mono(meth)acrylate, poly 1,2-butylene glycol mono(meth)acrylate, poly(ethylene glycol·trimethylene glycol) mono(meth)acrylate, polyethylene Glycol / polytrimethylene glycol mono(meth)acrylate, poly(propylene glycol / trimethylene glycol) mono(meth)acrylate, polypropylene glycol / polytrimethylene glycol mono(meth)acrylate, poly(trimethylene glycol / tetramethylene glycol) mono(meth)acrylate, polytrimethylene glycol / polytetramethylene glycol mono(meth)acrylate, poly(1,2-butylene glycol / trimethylene glycol) mono(meth)acrylate, poly 1,Examples include 2-butylene glycol-polytrimethylene glycol mono(meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, poly(1,2-butylene glycol-tetramethylene glycol) mono(meth)acrylate, and poly(1,2-butylene glycol-polytetramethylene glycol mono(meth)acrylate). The above "poly(ethylene glycol-propylene glycol)" refers to a random copolymer of ethylene glycol and propylene glycol, and "polyethylene glycol-polypropylene glycol" refers to a block copolymer of ethylene glycol and propylene glycol.

[0075] The polymerizable monomer (B) is preferably at least one selected from the group consisting of a compound represented by the following general formula (B-1), a compound represented by the following general formula (B-2), a compound represented by the following general formula (B-3), a compound represented by the following general formula (B-4), a compound represented by the following general formula (B-5), a compound represented by the following general formula (B-6), a compound represented by the following general formula (B-7), a compound represented by the following general formula (B-8), a compound represented by the following general formula (B-9), and a compound represented by the following general formula (B-10).

[0076] (In the general formulae (B-1), (B-2), (B-3), (B-4), (B-5), (B-6), (B-7), (B-8), (B-9) and (B-10), R ２１ is a hydrogen atom or a methyl group, R ２２ is an alkyl group having 1 to 18 carbon atoms; R ２３ is a hydrogen atom or a methyl group, R ２４ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms; R ２５ is a hydrogen atom or a methyl group, R ２６ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond, and R ２７is a hydrogen atom or a methyl group, R ２８ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond, and R ２９ is a hydrogen atom or a methyl group, R ３０ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, R ３１ ~R ３５ are each independently a hydrogen atom or a methyl group, and L １９ and L ２０ each independently represents a divalent organic group which may have an ether bond or a single bond, ２１ and L ２２ each independently represents a divalent organic group which may have an ether bond or a single bond, ２３ represents an r1+1 valent organic group which may have an ether bond or a single bond, and L ２４ is an r2+r3 valent organic group which may have an ether bond and / or an ester bond, and L ２５ is an r4+1-valent organic group which may have an ether bond, and L ２６ represents a single bond or an organic group having a valence of r5+1, which may have an ether bond; ２７ represents r6+a monovalent organic group which may have an ether bond or a single bond, m represents the number of repetitions, and the number average value of m is in the range of 1 to 200, p is an integer in the range of 1 to 10, q represents the number of repetitions, and the number average value of q is in the range of 1 to 100, l is an integer in the range of 0 to 5, r2 and r3 represent the number of repetitions, and are integers in the range of 1 to 3, and r1, r4, r5, and r6 represent the number of repetitions, and are 2 or 3.

[0077] In the formula (B-2), the m m's in the parentheses may be the same or different from each other. In the formula (B-3), the q p's in the parentheses may be the same or different from each other. In the formula (B-4), the q p's in the parentheses may be the same or different from each other. In the formula (B-8), the m m's in the parentheses may be the same or different from each other. In the formula (B-9), the q p's in the parentheses may be the same or different from each other. In the formula (B-10), the q p's in the parentheses may be the same or different from each other.

[0078] R ２２ , R ２４ , R ２６ and R ２８ The alkyl group having 1 to 18 carbon atoms may further have a substituent, and examples of the substituent include a hydroxyl group and an aryl group. ２６ and R ２８ The alkyl group having 1 to 18 carbon atoms and an ether bond may further have a substituent, and examples of the substituent include a hydroxyl group and an aryl group. ３０ The alkyl group having 1 to 6 carbon atoms may further have a substituent, and examples of the substituent include a hydroxyl group and an aryl group. ３０ The alkoxy group having 1 to 6 carbon atoms may further have a substituent, and examples of the substituent include a hydroxyl group and an aryl group.

[0079] L in the formulas (B-1) to (B-4) １９ ~L ２２ The divalent organic group is L １１ is a divalent organic group. ２３ ~L ２７ The same applies to the divalent organic group.

[0080] In the general formulae (B-2) and (B-8), m represents the number of repetitions, and may be, for example, an integer of 1 or greater. The number average of m is, for example, in the range of 1 to 100, preferably in the range of 2 to 30, and more preferably in the range of 3 to 15. The number average of m can be confirmed by measuring the number average molecular weight of the polymerizable monomer (B) by the method described in the examples.

[0081] In the general formulae (B-3), (B-4), (B-9) and (B-10), q represents the number of repetitions, and may be, for example, an integer of 1 or greater. The number average of q is, for example, in the range of 1 to 100, preferably in the range of 2 to 30, and more preferably in the range of 3 to 15.

[0082] In the general formulae (B-6) to (B-10), r1 and r4 to r6 are preferably 2 or 3, more preferably 2. r2 and r3 are preferably 1 or 2, more preferably 1.

[0083] The polymerizable monomer (B) preferably includes the compounds represented by the above formulae (B-2), (B-7) and (B-8).

[0084] The polymerizable monomer (B) preferably contains one or more compounds selected from the group consisting of compounds represented by the formulas (B-2), (B-3), (B-4), (B-5), (B-6), (B-7), (B-8), (B-9), and (B-10). When the polymerizable monomer (B) contains one or more compounds selected from the group consisting of compounds represented by the formulas (B-2), (B-3), (B-4), (B-5), (B-6), (B-7), (B-8), (B-9), and (B-10), the total amount of the compounds represented by the formulas (B-2), (B-3), and (B-4) and the compounds represented by the formulas (B-7), (B-8), (B-9), and (B-10) relative to the total amount of the polymerizable monomer (B) is, for example, 1% by mass or more, preferably 5% by mass or more, and more preferably 7% by mass or more.

[0085] The polymerizable monomer (B) as a polymerization component may be one type alone or two or more types of polymerizable monomers (B) having different structures from each other.

[0086] The polymerizable monomer (B) can be produced by a known method, and a commercially available product may also be used.

[0087] In the polymer of the present invention, the content of the polymerizable monomer (B) is, for example, in the range of 0.1 to 900 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), preferably in the range of 1 to 500 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), more preferably in the range of 5 to 300 parts by mass relative to 100 parts by mass of the polymerizable monomer (A). Even more preferably in the range of 10 to 200 parts by mass relative to 100 parts by mass of the polymerizable monomer (A). The content of the polymerizable monomer (B) is the same for 100 parts by mass of the polymerizable monomer (A'), polymerizable monomer (A"), polymerizable monomer (A'"), and polymerizable monomer (A""). The content of the polymerizable monomer (B) can be adjusted by the raw material charge ratio of the polymerizable monomer (B) when producing the polymer of the present invention.

[0088] In the polymer of the present invention, the proportion of the polymerizable monomer (B) in the polymerization components is, for example, in the range of 5 to 90 mass%, preferably 10 to 80 mass%, more preferably 20 to 70 mass%, particularly preferably 30 to 60 mass%, based on the total amount of the polymerization components of the polymer.

[0089] The polymerization components of the polymer of the present invention preferably contain, as optional components, a polymerizable monomer (A), a polymerizable monomer (A'), a polymerizable monomer (A"), a polymerizable monomer (A'"), and a polymerizable monomer (C) having two or more polymerizable unsaturated groups other than the polymerizable monomer (A"").

[0090] The polymerizable monomer (C) is not particularly limited as long as it is a polymerizable monomer having two or more polymerizable unsaturated groups and does not fall under the category of the polymerizable monomer (A) or the polymerizable monomer (B), but is preferably a compound represented by the following general formula (C-1):

[0091] (In the general formula (C-1), R ３６ is a hydrogen atom or a methyl group; r is an integer of 2 or more; L ３１ is an organic group which may have an r-valent ether bond.

[0092] r may be an integer of 2 or more, for example, an integer in the range of 2 to 12, preferably an integer in the range of 2 to 8, more preferably an integer in the range of 2 to 6, and even more preferably an integer in the range of 2 to 4.

[0093] L ３１ The r-valent organic group is an organic group having a valence corresponding to the numerical value of r. For example, when r is 2, it is a divalent organic group, and when r is 6, it is a hexavalent organic group.

[0094] L ３１ is preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, and is an organic group in which a hydrogen atom bonded to a carbon atom of the alkylene group or the alkyleneoxy group is replaced with a bond so as to have a valence corresponding to the numerical value of r. ３１ When L is a divalent organic group, ３１ is preferably an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms.

[0095] L ３１ Examples of the alkylene group having 1 to 50 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, an n-decylene group, an n-dodecylene group, an isopropylene group, a 2-methylpropylene group, a 2-methylhexylene group, and a tetramethylethylene group.

[0096] L ３１ The alkylene group having 1 to 50 carbon atoms is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably a methylene group, an ethylene group, an n-propylene group, or an isopropylene group.

[0097] L ３１ The alkyleneoxy group having 1 to 50 carbon atoms may be, for example, one or more —CH ２ - is a group in which - is substituted with -O-. ３１The alkyleneoxy group having 1 to 50 carbon atoms is preferably an alkyleneoxy group having 1 to 15 carbon atoms, more preferably an alkyleneoxy group having 1 to 8 carbon atoms, and even more preferably a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, an oxytrimethylene group, a butyleneoxy group, an oxytetramethylene group, a pentyleneoxy group, a heptyleneoxy group, or an octyleneoxy group.

[0098] L ３１ When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, these divalent organic groups are -CH ２ A part of the - may be replaced by a carbonyl group (-C(=O)-), a phenylene group, a sulfide bond (-S-), an amide bond or a urethane bond.

[0099] L ３１ When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, a carbon atom of these groups may further be substituted with a substituent such as a hydroxyl group.

[0100] Specific examples of the polymerizable monomer (C) include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 2-hydroxy-3-methacrylpropyl acrylate, 2-hydroxy-1,3-dimethacryloxypropane, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated bisphenol A, Examples of the acrylate include Nol A di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, tris-(2-acryloxyethyl)isocyanurate, bis-(2-acryloxyethyl)isocyanurate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and polypentaerythritol poly(meth)acrylate.

[0101] The polymerizable monomer (C) as a polymerization component may be one type alone or two or more types of polymerizable monomers (C) having different structures.

[0102] The polymerizable monomer (C) can be produced by a known method, and a commercially available product may also be used.

[0103] In the polymer of the present invention, the content of the polymerizable monomer (C) is, for example, in the range of 1 to 300 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), preferably in the range of 5 to 250 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), more preferably in the range of 10 to 200 parts by mass relative to 100 parts by mass of the polymerizable monomer (A). It is even more preferably in the range of 10 to 150 parts by mass relative to 100 parts by mass of the polymerizable monomer (A). The content of the polymerizable monomer (C) can be adjusted by the raw material charge ratio of the polymerizable monomer (C) when producing the polymer of the present invention.

[0104] In the polymer of the present invention, the content of the polymerizable monomer (C) is, for example, 5 to 70 mass%, preferably 6 to 65 mass%, more preferably 7 to 60 mass%, particularly preferably 8 to 55 mass%, and most preferably 10 to 50 mass%, based on the total amount of polymerization components of the polymer.

[0105] The polymerization components of the polymer of the present invention may contain a polymerizable monomer (D) in which the number of polymerizable unsaturated groups in the polymerizable monomer (A) is one.

[0106] The polymerizable monomer (D) is preferably a compound represented by the following general formula (D-1).

[0107] (In the general formula (D-1), R ４１ are each independently an alkyl group having 1 to 6 carbon atoms or —OSi(R ４４ ) ３ A group represented by R ４４ are each independently an alkyl group having 1 to 3 carbon atoms, ４２ are each independently an alkyl group having 1 to 6 carbon atoms; R ４３ is an alkyl group having 1 to 12 carbon atoms, R ４５ is a hydrogen atom or a methyl group, and L ４１ represents a divalent organic group which may have an ether bond, and s represents the number of repetitions.

[0108] L ４１ The divalent organic group is preferably a single bond, an alkylene group having 1 to 50 carbon atoms, or an alkyleneoxy group having 1 to 50 carbon atoms.

[0109] L ４１ Examples of the alkylene group having 1 to 50 carbon atoms include a methylene group, an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n-nonylene group, an n-decylene group, an n-dodecylene group, an isopropylene group, a 2-methylpropylene group, a 2-methylhexylene group, and a tetramethylethylene group.

[0110] L ４１ The alkylene group having 1 to 50 carbon atoms is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and even more preferably a methylene group, an ethylene group, an n-propylene group, or an isopropylene group.

[0111] L ４１ The alkyleneoxy group having 1 to 50 carbon atoms is, for example, one of the alkylene groups -CH ２ - is a group in which - is substituted with -O-. ４１ The alkyleneoxy group having 1 to 50 carbon atoms is preferably an alkyleneoxy group having 1 to 15 carbon atoms, more preferably an alkyleneoxy group having 1 to 8 carbon atoms, and even more preferably a methyleneoxy group, an ethyleneoxy group, a propyleneoxy group, an oxytrimethylene group, a butyleneoxy group, an oxytetramethylene group, a pentyleneoxy group, a heptyleneoxy group, or an octyleneoxy group.

[0112] L ４１ When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, these divalent organic groups are -CH ２ A part of the - may be replaced by a carbonyl group (-C(=O)-), a phenylene group, an amide bond or a urethane bond, and furthermore, a hydroxyl group or the like may be substituted on the carbon atom.

[0113] The number of repetitions of s may be, for example, an integer of 1 or more. The number average of s is, for example, in the range of 1 to 150, preferably in the range of 1 to 100, more preferably in the range of 1 to 50, and even more preferably in the range of 1 to 25. The number average of s can be confirmed by measuring the number average molecular weight of the polymerizable monomer (D) by the method described in the examples.

[0114] R ４１ and R ４２ The alkyl group having 1 to 6 carbon atoms in R is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. ４３ The alkyl group having 1 to 12 carbon atoms is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms.

[0115] The polymerizable monomer (D) can be produced by a known method, or a commercially available product may be used. Specific examples of the polymerizable monomer (D) include α-(3-methacryloyloxy)propylpolydimethylsiloxane and 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane.

[0116] The polymerizable monomer (D) as a polymerization component may be one type alone or two or more types.

[0117] In the polymer of the present invention, the content of the polymerizable monomer (D) is, for example, in the range of 10 to 500 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), preferably in the range of 30 to 400 parts by mass relative to 100 parts by mass of the polymerizable monomer (A), and more preferably in the range of 50 to 300 parts by mass relative to 100 parts by mass of the polymerizable monomer (A). The content of the polymerizable monomer (D) can be adjusted by the raw material charging ratio of the polymerizable monomer (D) when producing the polymer of the present invention.

[0118] The polymer of the present invention may be, for example, a polymer containing polymerizable monomer (A), an optional polymerizable monomer (B), and an optional polymerizable monomer (C) as polymerization components. It may also contain other polymerizable monomers as polymerization components other than polymerizable monomer (A), the optional polymerizable monomer (B), and the optional polymerizable monomer (C), as long as the effects of the present invention are not impaired. Examples of such other polymerizable monomers as polymerization components include the above-mentioned polymerizable monomer (D). The polymer of the present invention is preferably a polymer whose polymerization components are essentially composed of polymerizable monomer (A) and the optional polymerizable monomer (B) and / or the optional polymerizable monomer (C), and more preferably a copolymer whose polymerization components are composed only of polymerizable monomer (A), the optional polymerizable monomer (B), and / or the optional polymerizable monomer (C). Here, "substantially consisting of" means that the total content of the polymerizable monomer (A), the optional polymerizable monomer (B) and the optional polymerizable monomer (C) in the polymerization components of the polymer of the present invention is 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more.

[0119] The polymerization mode of the polymer of the present invention is not particularly limited. The polymer of the present invention may be, for example, a random polymer of the polymerizable monomer (A), the optional polymerizable monomer (B), and the optional polymerizable monomer (C). Furthermore, the polymer of the present invention may be, for example, a block polymer having one or more polymer blocks of the polymerizable monomer (A), the optional polymerizable monomer (B), and the optional polymerizable monomer (C).

[0120] The polymer of the present invention preferably does not contain fluorine atoms in order to reduce the environmental load.

[0121] The number average molecular weight (Mn) of the polymer of the present invention is preferably in the range of 1,000 to 50,000, more preferably in the range of 1,000 to 30,000, and even more preferably in the range of 1,500 to 10,000. The weight average molecular weight (Mw) of the polymer of the present invention is preferably in the range of 1,000 to 300,000, more preferably in the range of 1,500 to 200,000, even more preferably in the range of 2,000 to 100,000, and particularly preferably in the range of 3,000 to 50,000.

[0122] In the present invention, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​measured by gel permeation chromatography (GPC) and converted into polystyrene equivalents. The number average molecular weight (Mn) and weight average molecular weight (Mw) values ​​of the polymer of the present invention are measured by the method described in the examples.

[0123] The defoaming agent of the present invention may contain a defoaming agent other than the polymer of the present invention, as long as it contains the polymer of the present invention. Furthermore, the defoaming agent of the present invention may be the polymer of the present invention.

[0124] [Method for Producing Polymer] The method for producing the polymer of the present invention is not particularly limited, and the polymer can be produced by a known method. The polymer of the present invention can be produced by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, or the like, based on a polymerization mechanism such as a radical polymerization method, a cationic polymerization method, or an anionic polymerization method. For example, in the case of a radical polymerization method, the polymer of the present invention can be produced by charging a polymerizable monomer mixture into an organic solvent and adding a general-purpose radical polymerization initiator.

[0125] As the polymerization initiator, various types can be used, for example, peroxides such as t-butylperoxy-2-ethylhexanoate, benzoyl peroxide, and diacyl peroxide, azo compounds such as azobisisobutyronitrile, dimethyl azobisisobutyrate, and phenylazotriphenylmethane, Mn(acac) ３ If necessary, a chain transfer agent such as lauryl mercaptan, 2-mercaptoethanol, ethyl thioglycolic acid, or octyl thioglycolic acid, or a thiol compound having a coupling group such as γ-mercaptopropyltrimethoxysilane may be used as an additive such as a chain transfer agent.

[0126] Examples of the organic solvent include alcohols such as ethanol, isopropyl alcohol, n-butanol, iso-butanol, and tert-butanol; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and methyl amyl ketone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and butyl lactate; monocarboxylic acid esters such as methyl 2-oxypropionate, ethyl 2-oxypropionate, propyl 2-oxypropionate, butyl 2-oxypropionate, methyl 2-methoxypropionate, ethyl 2-methoxypropionate, propyl 2-methoxypropionate, and butyl 2-methoxypropionate; dimethylformamide, dimethyl sulfoxide, N-methyl Examples of the solvent include polar solvents such as pyrrolidone, ethers such as methyl cellosolve, cellosolve, butyl cellosolve, butyl carbitol, and ethyl cellosolve acetate, propylene glycols and esters thereof such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, and propylene glycol monobutyl ether acetate, halogenated solvents such as 1,1,1-trichloroethane and chloroform, ethers such as tetrahydrofuran and dioxane, aromatic solvents such as benzene, toluene, and xylene, and fluorinated inert liquids such as perfluorooctane and perfluorotri-n-butylamine. These solvents can be used alone or in combination of two or more.

[0127] The polymer of the present invention can also be produced by living polymerization such as living radical polymerization or living anionic polymerization.

[0128] In living radical polymerization, a dormant species, whose active polymerization terminal is protected by an atom or atomic group, reversibly generates radicals and reacts with a monomer, thereby causing a propagation reaction. Even when a first monomer is consumed, the propagating terminal does not lose its activity and continues to react with a second monomer that is added sequentially to produce a block polymer. Examples of such living radical polymerization include atom transfer radical polymerization (ATRP), reversible addition-fragmentation radical polymerization (RAFT), nitroxide-mediated radical polymerization (NMP), and organotellurium radical polymerization (TERP). While there are no particular restrictions on which of these methods is used, ATRP is preferred due to its ease of control. ATRP uses an organic halide or a sulfonyl halide compound as a polymerization initiator and a metal complex composed of a transition metal compound and a ligand as a catalyst.

[0129] Specific examples of polymerization initiators that can be used in ATRP include 1-phenylethyl chloride, 1-phenylethyl bromide, chloroform, carbon tetrachloride, 2-chloropropionitrile, α,α'-dichloroxylene, α,α'-dibromoxylene, hexakis(α-bromomethyl)benzene, and C1-6 alkyl esters of C2-halogenated carboxylic acids (e.g., 2-chloropropionic acid, 2-bromopropionic acid, 2-chloroisobutyric acid, 2-bromoisobutyric acid, etc.). More specific examples of C1-6 alkyl esters of C2-halogenated carboxylic acids include, for example, methyl 2-chloropropionate, ethyl 2-chloropropionate, methyl 2-bromopropionate, and ethyl 2-bromoisobutyrate.

[0130] The transition metal compounds that can be used in ATRP are M ｎ＋ X ｎ It is expressed as follows: M ｎ＋ X ｎ The transition metal M of the transition metal compound represented by ｎ＋ As the ＋ , Cu ２＋ , Fe ２＋ , Fe ３＋ , Ru ２＋ , Ru ３＋, Cr ２＋ , Cr ３＋ , Mo ０ , Mo ＋ , Mo ２＋ , Mo ３＋ , W ２＋ , W ３＋ , Rh ３＋ , Rh ４＋ , Co ＋ , Co ２＋ , Re ２＋ , Re ３＋ , Ni ０ , Ni ＋ , Mn ３＋ , Mn ４＋ , V ２＋ , V ３＋ , Zn ＋ , Zn ２＋ , Au ＋ , Au ２＋ , Ag ＋ and Ag ２＋ M ｎ＋ X ｎ X in the transition metal compound represented by the formula (I) is a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, (SO ４ ) １／２ , (PO ４ ) １／３ , (HPO ４ ) １／２ , (H ２ P.O. ４ ), triflate, hexafluorophosphate, methanesulfonate, arylsulfonate (preferably benzenesulfonate or toluenesulfonate), SeR １１ , CN and R １２ COO, where R １１ represents an aryl group or a linear or branched alkyl group having 1 to 20 carbon atoms (preferably 1 to 10 carbon atoms), R １２ represents a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms (preferably a methyl group) which may be substituted 1 to 5 times with halogen (preferably 1 to 3 times with fluorine or chlorine). ｎ＋ X ｎ In the transition metal compound represented by the formula (I), n represents the formal charge on the metal and is an integer of 0 to 7.

[0131] Examples of the ligand compound capable of forming a coordinate bond to the transition metal of the transition metal compound include a compound having a ligand containing one or more nitrogen atoms, oxygen atoms, phosphorus atoms, or sulfur atoms that can be coordinated to the transition metal via a σ bond, a compound having a ligand containing two or more carbon atoms that can be coordinated to the transition metal via a π bond, and a compound having a ligand that can be coordinated to the transition metal via a μ bond or an η bond.

[0132] The transition metal complex is not particularly limited, but preferred examples include complexes of transition metals of Groups 7, 8, 9, 10, and 11, and more preferred examples include complexes of zero-valent copper, monovalent copper, divalent ruthenium, divalent iron, or divalent nickel.

[0133] Specific examples of catalysts that can be used in ATRP include complexes with ligands such as 2,2'-bipyridyl and its derivatives, 1,10-phenanthroline and its derivatives, and polyamines such as tetramethylethylenediamine, pentamethyldiethylenetriamine, and hexamethyltris(2-aminoethyl)amine when the central metal is copper. Examples of divalent ruthenium complexes include dichlorotris(triphenylphosphine)ruthenium, dichlorotris(tributylphosphine)ruthenium, dichloro(cyclooctadiene)ruthenium, dichlorobenzeneruthenium, dichloro-p-cymeneruthenium, dichloro(norbornadiene)ruthenium, cis-dichlorobis(2,2'-bipyridine)ruthenium, dichlorotris(1,10-phenanthroline)ruthenium, and carbonylchlorohydridotris(triphenylphosphine)ruthenium. Examples of divalent iron complexes include bistriphenylphosphine complexes and triazacyclononane complexes.

[0134] In living radical polymerization, it is preferable to use a solvent. Examples of solvents used in living radical polymerization include ester solvents such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ether solvents such as diisopropyl ether, dimethoxyethane, and diethylene glycol dimethyl ether; halogenated solvents such as dichloromethane and dichloroethane; aromatic solvents such as toluene and xylene; ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as methanol, ethanol, and isopropanol; and aprotic polar solvents such as dimethylformamide and dimethyl sulfoxide. The above solvents may be used alone or in combination of two or more.

[0135] The polymerization temperature during the living radical polymerization is preferably in the range of room temperature to 120°C.

[0136] When the polymer of the present invention is produced by living radical polymerization, metals resulting from the transition metal compound used in the polymerization may remain in the resulting polymer. The metals remaining in the resulting polymer may be removed using activated alumina or the like after the polymerization is completed.

[0137] [Lubricating Oil Composition] The antifoaming agent of the present invention can be suitably used as an antifoaming agent for lubricating oil compositions, and the lubricating oil compositions of the present invention contain the antifoaming agent of the present invention.

[0138] The defoaming agent of the present invention is a polymer having a crosslinked structure by using a polymerizable monomer (A) having two or more polymerizable unsaturated groups as a polymerization component, and can suppress molecular spreading of the defoaming agent even in a high-temperature environment, thereby maintaining low solubility in a lubricating base oil. As a result, the defoaming agent of the present invention can exhibit high defoaming performance even in a high-temperature environment. Furthermore, in machines equipped with internal combustion engines or electric motors, high shear forces are applied to the drive parts of the machines, but the defoaming agent of the present invention suppresses molecular weight reduction due to its crosslinked structure, thereby suppressing deterioration of defoaming performance.

[0139] As described above, the antifoaming agent of the present invention has high antifoaming performance and can be used without restriction in lubricating oil compositions for drive system devices such as shock absorbers, transmissions, and power steering systems of automobiles.

[0140] The content of the antifoaming agent of the present invention in the lubricating oil composition of the present invention is not particularly limited, and is, for example, in the range of 1 to 1,000 ppm by mass, preferably in the range of 5 to 700 ppm by mass, and more preferably in the range of 10 to 400 ppm by mass, of the total amount of the lubricating oil composition.

[0141] The lubricating base oil for the lubricating oil composition of the present invention may be any known oil, and may be a mineral oil, a synthetic oil, or a mixture of a mineral oil and a synthetic oil.

[0142] Examples of mineral oils include those obtained by subjecting lubricating oil fractions obtained by vacuum distillation of atmospheric residue obtained by atmospheric distillation of crude oil to one or more of solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, etc., and examples of such mineral oils include paraffinic mineral oils and naphthenic mineral oils.Further examples include mineral oils produced by isomerizing mineral oil waxes and waxes produced by the Fischer-Tropsch process (GTL waxes).

[0143] Examples of synthetic oils include polyolefins such as polybutene, α-olefin homopolymers and copolymers (e.g., ethylene-α-olefin copolymers), various esters such as polyol esters, dibasic acid esters, and phosphate esters, various ethers such as polyphenyl ether, polyglycols, alkylbenzenes, and alkylnaphthalenes.

[0144] The lubricating base oil may be used alone or in combination of two or more.

[0145] The kinematic viscosity of the lubricating base oil at 100°C is preferably 1 to 20 mm ２ / s, more preferably 2 to 15 mm ２ / s, and more preferably 2 to 10 mm ２When the kinematic viscosity at 100°C of the lubricating base oil is in the above range, evaporation loss is small and power loss due to viscous resistance is not so large, so that the fuel economy improvement effect is easily obtained.

[0146] The lubricating base oil preferably has a paraffin content (sometimes referred to as %Cp) determined by ndM ring analysis of 70% or more, more preferably 75% or more, and even more preferably 80% or more. When the paraffin content is in the above range, the lubricating base oil has good oxidation stability and the like.

[0147] The content of the lubricating base oil in the lubricating oil composition is, for example, in the range of 65 to 95 mass %, preferably 70 to 95 mass %, and more preferably 70 to 90 mass %, of the total amount of the lubricating oil composition.

[0148] The lubricating oil composition of the present invention may contain the antifoam agent of the present invention and a lubricating base oil, and may further contain other additives. Examples of other additives include ashless detergents, ashless friction modifiers, antiwear agents, extreme pressure agents, viscosity index improvers, metal deactivators, pour point depressants, and rust inhibitors. These additives may be used alone or in combination.

[0149] The content of each of the other additives can be adjusted as appropriate within a range that does not impair the effects of the present invention, and is typically 0.001 to 25 mass%, preferably 0.005 to 20 mass%, more preferably 0.01 to 15 mass%, based on the total amount of the lubricating oil composition. The total content of the other additives is preferably 25 mass% or less, more preferably 20 mass% or less, and even more preferably 15 mass% or less, based on the total amount of the lubricating oil composition.

[0150] Examples of ashless detergents include alkenyl succinimides such as alkenyl succinic acid monoimide and alkenyl succinic acid bisimide, and boron-modified alkenyl succinimide.

[0151] Examples of ashless friction modifiers include aliphatic amines, fatty acid esters, fatty acid amides, fatty acids, fatty alcohols, and aliphatic ethers, each of which has at least one alkyl or alkenyl group having 6 to 30 carbon atoms in the molecule.

[0152] Examples of anti-wear agents or extreme pressure agents include sulfur-containing compounds such as zinc dithiophosphate; phosphorus-containing compounds such as phosphites, phosphate esters, phosphonate esters, and their amine salts or metal salts; and sulfur- and phosphorus-containing anti-wear agents such as thiophosphites, thiophosphate esters, thiophosphonate esters, and their amine salts or metal salts.

[0153] Examples of viscosity index improvers include polymethacrylate, disperse polymethacrylate, olefin copolymers (e.g., ethylene-propylene copolymers), disperse olefin copolymers, and styrene copolymers (e.g., styrene-diene copolymers, styrene-isoprene copolymers).

[0154] Examples of metal deactivators include benzotriazole-based compounds, tolyltriazole-based compounds, imidazole-based compounds, and pyrimidine-based compounds.

[0155] Examples of pour point depressants include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates, and polyalkylstyrenes.

[0156] Examples of the rust inhibitor include petroleum sulfonates, alkylbenzene sulfonates, dinonylnaphthalene sulfonates, alkenyl succinates, polyhydric alcohol esters, and the like.

[0157] The lubricating oil composition of the present invention is suitable for use in lubricating the drive parts of machines equipped with an internal combustion engine or an electric motor. Regarding the lubrication of the drive parts, for example, in an electric vehicle, the drive part generally integrates a motor, an inverter, and a gearbox, and the drive parts can be lubricated by filling the gearbox with the lubricating oil composition of the present invention. Furthermore, in the case of a gasoline-powered vehicle, the drive part, which is the internal combustion engine, the lubricating oil composition of the present invention is stored in an oil pan and supplied to the cylinder via an oil pump, thereby lubricating the starting parts. The lubrication of the drive parts is not limited to these forms, and the drive parts can be lubricated by filling or supplying the lubricating oil composition of the present invention to parts where metals come into contact with each other.

[0158] The lubricating oil composition of the present invention can be used in any machine equipped with an internal combustion engine or an electric motor, including automobiles (gasoline-powered vehicles, electric vehicles), robots (industrial robots, entertainment robots), aircraft (airplanes, helicopters), ships, and various home appliances.

[0159] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0160] In the examples and comparative examples, the weight average molecular weight (Mw) and number average molecular weight (Mn) are values ​​calculated in terms of polystyrene based on gel permeation chromatography (GPC) measurements. The GPC measurement conditions are as follows. In the chemical formula, n represents any repeating unit.

[0161] [GPC measurement conditions] Measurement apparatus: High-speed GPC apparatus "HLC-8320GPC" manufactured by Tosoh Corporation Column: "TSK GUARDCOLUMN SuperHZ-L" manufactured by Tosoh Corporation + "TSK gel SuperHZM-N" manufactured by Tosoh Corporation + "TSK gel SuperHZM-N" manufactured by Tosoh Corporation + "TSK gel SuperHZM-N" manufactured by Tosoh Corporation + "TSK gel SuperHZM-N" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: "EcoSEC Data Analysis Version 1.07" manufactured by Tosoh Corporation Column temperature: 40°C Developing solvent: tetrahydrofuran Flow rate: 0.35 mL / min Measurement sample: 7.5 mg of sample was dissolved in 10 ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to prepare the measurement sample. Sample injection amount: 20 μL Standard sample: The following monodisperse polystyrene with known molecular weight was used in accordance with the measurement manual for the "HLC-8320GPC".

[0162] (Monodisperse polystyrene) "A-300" manufactured by Tosoh Corporation "A-500" manufactured by Tosoh Corporation "A-1000" manufactured by Tosoh Corporation "A-2500" manufactured by Tosoh Corporation "A-5000" manufactured by Tosoh Corporation "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation "F-10" manufactured by Tosoh Corporation "F-20" manufactured by Tosoh Corporation "F-40" manufactured by Tosoh Corporation "F-80" manufactured by Tosoh Corporation "F-128" manufactured by Tosoh Corporation "F-288" manufactured by Tosoh Corporation

[0163] Synthesis Example 1 Synthesis of Defoamer (1) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 40 parts by mass of dipropylene glycol monomethyl ether acetate as a solvent, and the temperature was raised to 105°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution prepared by dissolving 25 parts by mass of a silicone dimethacrylate monomer (number average molecular weight: 1,000; in the formula, n is a repeating unit) represented by the following general formula (A1) and 25 parts by mass of methoxypolyethylene glycol acrylate (the number of repeating ethylene oxide chains is approximately 9) in 140 parts by mass of dipropylene glycol monomethyl ether acetate; and a polymerization initiator solution prepared by dissolving 7.5 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 20 parts by mass of dipropylene glycol monomethyl ether acetate. These two types of dropping liquids were simultaneously added dropwise over 2 hours while maintaining the temperature in the flask at 105°C. After the dropwise addition was completed, the mixture was stirred at 105° C. for 4 hours to obtain a solution of antifoaming agent (1).

[0164]

[0165] The molecular weight of the obtained defoaming agent (1) was measured by GPC and found to be a weight average molecular weight (Mw) of 13,300.

[0166] Synthesis Example 2 Synthesis of Defoamer (2) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 30 parts by mass of dipropylene glycol monomethyl ether acetate as a solvent, and the temperature was raised to 110°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution prepared by dissolving 12.5 parts by mass of a silicone dimethacrylate monomer (number average molecular weight: 1,000) represented by the general formula (A1) and 12.5 parts by mass of polyethylene glycol dimethacrylate (the number of repeating ethylene oxide chains is approximately 9) in 60 parts by mass of dipropylene glycol monomethyl ether acetate; and a polymerization initiator solution prepared by dissolving 7.5 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 10 parts by mass of dipropylene glycol monomethyl ether acetate. These two types of dropping liquids were simultaneously added dropwise over 2 hours while maintaining the temperature inside the flask at 110°C. After the dropwise addition was completed, the mixture was stirred at 110° C. for 3 hours to obtain a solution of antifoaming agent (2).

[0167] The molecular weight of the obtained defoaming agent (2) was measured by GPC and found to be 36,700 in weight average molecular weight (Mw).

[0168] Synthesis Example 3: Synthesis of Defoamer (3) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 100 parts by mass of a silicone compound (number average molecular weight: 1,000) represented by the following general formula (A3-1), 90 parts by mass of heptane, and 0.1 parts by mass of stannous octoate. Next, stirring was started under an air stream, the temperature inside the flask was raised to 75°C, and 30 parts by mass of 2-isocyanatoethyl acrylate was added dropwise over 15 minutes. After completion of the dropwise addition, the temperature was raised to 80°C and the reaction was carried out by stirring for 1 hour. As a result, disappearance of the absorption peak of the isocyanate group was confirmed by IR spectrum measurement. This yielded a silicone diacrylate monomer represented by the following general formula (A3).

[0169]

[0170] A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 30 parts by mass of butyl acetate as a solvent and heated to 100°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution prepared by dissolving 20 parts by mass of silicone diacrylate monomer represented by the general formula (A3) and 20 parts by mass of methoxypolyethylene glycol acrylate (having an ethylene oxide chain repeat number of approximately 9) in 55 parts by mass of butyl acetate, and a polymerization initiator solution prepared by dissolving 2 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 10 parts by mass of butyl acetate. These were then simultaneously added dropwise over 2 hours while maintaining the temperature inside the flask at 100°C. After completion of the dropping, the mixture was stirred at 100°C for 4 hours to obtain a solution of defoaming agent (3).

[0171] The molecular weight of the obtained defoaming agent (3) was measured by GPC and found to be 18,800 in weight average molecular weight (Mw).

[0172] Synthesis Example 4: Synthesis of antifoaming agent (4) A glass flask equipped with a stirrer, a thermometer, a condenser, and a dropping device was charged with 215 parts by mass of a silicone compound represented by the following general formula (A4-1), 30 parts by mass of 1,3-dimercapto-2-propanol, 200 parts by mass of methyl ethyl ketone, and 0.1 parts by mass of NaH. Stirring was then initiated under a nitrogen atmosphere, the temperature inside the flask was raised to 60°C, and stirring was continued for 1.5 hours to obtain a silicone compound represented by the following general formula (A4-2).

[0173]

[0174] A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 50 parts by mass of the silicone compound represented by the general formula (A4-2), 40 parts by mass of heptane, and 0.1 parts by mass of stannous octoate. Stirring was then initiated under an air stream, the temperature inside the flask was raised to 75°C, and 13 parts by mass of 1,1-(bisacryloyloxymethyl)ethyl isocyanate was added dropwise over 15 minutes. After the dropwise addition was completed, the temperature was raised to 80°C and the reaction was continued with stirring for 1 hour. As a result, IR spectrum measurement confirmed the disappearance of the absorption peak of the isocyanate group. This yielded a silicone diacrylate monomer represented by the following general formula (A4):

[0175]

[0176] A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 52 parts by mass of n-butyl acetate as a solvent, and the temperature was raised to 85°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution prepared by dissolving 30 parts by mass of silicone diacrylate monomer represented by the general formula (A4) and 20 parts by mass of methoxypolyethylene glycol methacrylate (the number of repeating ethylene oxide chains is approximately 9) in 50 parts by mass of butyl acetate, and a polymerization initiator solution prepared by dissolving 3 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 15 parts by mass of n-butyl acetate. These were then dropped simultaneously over a period of 2 hours while maintaining the temperature inside the flask at 85°C. After completion of the dropping, the mixture was stirred at 85°C for 4 hours, then the temperature was raised to 110°C, and the mixture was stirred for an additional 1 hour to obtain a solution of defoamer (4).

[0177] The molecular weight of the obtained defoaming agent (4) was measured by GPC and found to be a weight average molecular weight (Mw) of 5,400.

[0178] Synthesis Example 5 Synthesis of Defoamer (5) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 50 parts by mass of propylene glycol methyl ether acetate as a solvent, and the temperature was raised to 105°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution obtained by dissolving 6.75 parts by mass of a cyclic silicone monomer represented by the following chemical formula (A5), 16.8 parts by mass of methoxypolyethylene glycol acrylate (the number of repeating ethylene oxide chains is approximately 9), and 12.1 parts by mass of a silicone compound represented by general formula (A4-1) in 65 parts by mass of propylene glycol methyl ether acetate; and a polymerization initiator solution obtained by dissolving 7.1 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 10 parts by mass of propylene glycol methyl ether acetate. These were then dropped simultaneously over 2 hours while the temperature in the flask was maintained at 105°C. After the dropwise addition was completed, the mixture was stirred at 105° C. for 3 hours to obtain a solution of antifoaming agent (5).

[0179]

[0180] The molecular weight of the obtained defoaming agent (5) was measured by GPC and found to be a weight average molecular weight (Mw) of 26,000.

[0181] Synthesis Example 6: Synthesis of Defoamer (6) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 60 parts by mass of propylene glycol methyl ether acetate as a solvent, and the temperature was raised to 105°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution obtained by dissolving 25 parts by mass of a silicone monomer represented by the following chemical formula (A6) and 25 parts by mass of methoxypolyethylene glycol acrylate (the number of repeating ethylene oxide chains is approximately 9) in 100 parts by mass of propylene glycol methyl ether acetate; and a polymerization initiator solution obtained by dissolving 5 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 20 parts by mass of propylene glycol methyl ether acetate. These were simultaneously added dropwise over 2 hours while maintaining the temperature in the flask at 105°C. After completion of the dropping, the mixture was stirred at 105°C for 3 hours to obtain a solution of defoamer (6).

[0182]

[0183] The molecular weight of the obtained defoaming agent (6) was measured by GPC and found to be a weight average molecular weight (Mw) of 10,000.

[0184] Synthesis Example 7: Synthesis of Defoamer (7) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 34 parts by mass of n-butyl acetate as a solvent, and the temperature was raised to 95°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping devices: a monomer solution prepared by dissolving 16 parts by mass of a silicone monomer mixture represented by the following formulae (A7), (A8), and (A9), 15 parts by mass of methoxypolyethylene glycol methacrylate (the number of repeating ethylene oxide chains is approximately 9), and 3 parts by mass of methyl methacrylate in 33 parts by mass of n-butyl acetate; and a polymerization initiator solution prepared by dissolving 3 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 10 parts by mass of n-butyl acetate. These were simultaneously added dropwise over a period of 2 hours while maintaining the temperature inside the flask at 95°C. After completion of the dropping, the mixture was stirred at 95°C for 2 hours, then the temperature was raised to 110°C, and stirring was continued for an additional hour to obtain a solution of defoamer (7).

[0185] (t1, t2, and t3 are repeating units, each an integer of 0 to 7)

[0186] The molecular weight of the obtained defoaming agent (7) was measured by GPC, and the average weight average molecular weight (Mw) was 44,000.

[0187] Synthesis Example 8 Synthesis of Antifoaming Agent (8) A glass flask equipped with a stirrer, a thermometer, a condenser, and a dropping device was charged with 30 parts by mass of propylene glycol methyl ether acetate as a solvent, and the temperature was raised to 105°C while stirring under a nitrogen stream. Next, two types of dropping liquids were placed in separate dropping apparatuses, and simultaneously added dropwise over two hours while maintaining the temperature in the flask at 105°C. After completion of the dropping, the mixture was stirred at 105°C for 3 hours to obtain a solution of defoamer (8).

[0188]

[0189] The molecular weight of the obtained defoaming agent (8) was measured by GPC and found to be a weight average molecular weight (Mw) of 20,000.

[0190] (Synthesis Comparative Example 1: Synthesis of Defoamer (1')) A glass flask equipped with a stirrer, thermometer, condenser, and dropping device was charged with 52 parts by mass of n-butyl acetate as a solvent, and the temperature was raised to 85°C while stirring under a nitrogen stream. Next, 30 parts by mass of 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane dissolved in 50 parts by mass of n-butyl acetate, 20 parts by mass of methoxypolyethylene glycol methacrylate (the number of repeating ethylene oxide chains is approximately 9), and two types of dropping liquids were placed in separate dropping devices: a polymerization initiator solution in which 3 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 15 parts by mass of n-butyl acetate. While maintaining the temperature inside the flask at 85°C, the monomer solution and the polymerization initiator solution were simultaneously added dropwise over 2 hours. After completion of the dropping, the mixture was stirred at 85°C for 4 hours, then the temperature was raised to 110°C, and further stirred for 1 hour to obtain a solution of defoamer (1').

[0191] The molecular weight of the resulting antifoaming agent (1') was measured by GPC and found to be 40,000 in weight average molecular weight (Mw).

[0192] (Synthesis Comparative Example 2: Synthesis of Defoaming Agent (2')) A solution of defoaming agent (2') was obtained in the same manner as in Synthesis Comparative Example 1, except that 30 parts by mass of a compound (number average molecular weight 5,000) represented by the following general formula (A2') was used instead of 3-methacryloyloxypropyltris(trimethylsiloxy)silane.

[0193]

[0194] The molecular weight of the resulting antifoaming agent (2') was measured by GPC and found to be a weight average molecular weight (Mw) of 25,000.

[0195] (Synthesis Comparative Example 3: Synthesis of Defoaming Agent (3')) A solution of defoaming agent (3') was obtained in the same manner as in Synthesis Comparative Example 1, except that 30 parts by mass of the compound (number average molecular weight 1,000) represented by the above general formula (A2') was used instead of 3-methacryloyloxypropyltris(trimethylsiloxy)silane.

[0196] The molecular weight of the resulting antifoaming agent (3') was measured by GPC and found to be a weight average molecular weight (Mw) of 27,000.

[0197] A commercially available dimethyl silicone ("KF-96-50,000cs" manufactured by Shin-Etsu Silicones Co., Ltd.) shown below was separately prepared as an antifoaming agent (4').

[0198]

[0199] The defoaming performance of the defoaming agent was evaluated by carrying out the following foaming test using the defoaming agent produced above. The results are shown in Table 1.

[0200] (Preparation of Lubricating Oil Composition) A lubricating oil composition was prepared by adding the amount of an antifoaming agent shown in Table 1 diluted with kerosene shown in Table 1 to 100 parts by mass of a base lubricating oil containing a lubricating base oil (paraffinic mineral oil) as the main component and small amounts of various additives (viscosity index improver, phosphite ester compound, thiadiazole compound, calcium-based detergent, metal deactivator, ashless dispersant, antioxidant, etc.). In Comparative Example 5, no antifoaming agent was added.

[0201] The resulting lubricating oil composition was subjected to the following foaming test. The results are shown in Table 1. (Foaming Test) The foaming test was conducted in accordance with the homogenizer method disclosed in JP 2008-120880 A. Using a homogenizer ("T.K. Robomix" manufactured by Primix Corporation) equipped with a generator shaft ("Mini Mixer" manufactured by Primix Corporation), the lubricating oil composition was stirred under the following conditions, and the foam volume (mL) was determined by subtracting the oil surface reading (mL) before stirring from the foam surface reading (mL) 3 seconds after stirring was completed. A smaller foam volume indicates better defoaming properties. Rotation speed: 16,000 rpm Oil temperature: 80°C or 120°C Oil volume: 80 ml Container: 200 ml measuring cylinder (inner diameter φ36 mm) Stirring time: 1 minute

[0202]

[0203] From the results in Table 1, it can be seen that all of the defoaming agents (1) to (8), which are polymers containing a polymerizable monomer having a specific silicone functional group and two or more polymerizable unsaturated groups, exhibit excellent defoaming properties even in a high-temperature environment. On the other hand, all of the defoaming agents (1') to (4'), which do not contain a polymerizable monomer having a specific silicone functional group and two or more polymerizable unsaturated groups as a polymerization component, do not exhibit sufficient defoaming properties in a high-temperature environment.

Claims

1. -[OSi(R) ２ ] ｘ -(each R is independently an alkyl group having 1 to 6 carbon atoms, and x is the number of repetitions), and a polymerizable monomer (a1) having two or more polymerizable unsaturated groups and / or -Si[OSi(R ３ ] ｎ [R'] ３－ｎ (n is an integer of 1 to 3; each R is independently an alkyl group having 1 to 6 carbon atoms; each R' is independently an alkyl group having 1 to 6 carbon atoms), and contains, as at least a polymerization component, a polymerizable monomer (A), which is a polymerizable monomer (a2) having two or more polymerizable unsaturated groups.

2. The defoaming agent according to claim 1, wherein the polymerizable monomer (A) is a compound represented by the following general formula (A-1) and / or a compound represented by the following general formula (A-2): (In the general formula (A-1) and the general formula (A-2), R １１ are each independently an alkyl group having 1 to 6 carbon atoms; R １２ are each independently an alkyl group having 1 to 6 carbon atoms; R １３ are each independently a hydrogen atom or a methyl group; R １４ is an alkyl group having 1 to 12 carbon atoms; R １５ each independently represents an alkyl group having 1 to 6 carbon atoms or —OSi(R １６ ) ３ A group represented by R １６ each independently represents an alkyl group having 1 to 6 carbon atoms; x represents the number of repetitions; y represents an integer of 1 or more; z1 and z2 each independently represent an integer of 1 or more; z3 represents an integer of 2 or more; L １１ z is an organic group having a valence of 1+1 and may have an ether bond; L １２ z is an organic group having a valence of 2+1 and may have an ether bond; L １３ is an organic group having a valence of z+y which may have an ether bond, １４ is a divalent organic group which may have an ether bond.

3. A defoaming agent containing a polymer having as at least a polymerization component a polymerizable monomer (A') which is a compound represented by the following general formula (A-3): (In the above general formula (A-3), R １３ are each independently a hydrogen atom or a methyl group; R ５１ are each independently an alkyl group having 1 to 6 carbon atoms; １５ each independently represents a divalent organic group which may have an ether bond; a represents a repeating unit and is an integer of 0 to 3.

4. A defoaming agent containing a polymer having as at least a polymerization component a polymerizable monomer (A″) which is a compound represented by the following general formula (A-4): (In the above general formula (A-4), R １３ are each independently a hydrogen atom or a methyl group; R ５２ are each independently an alkyl group having 1 to 6 carbon atoms; １６ are each independently a divalent organic group which may have an ether bond.

5. A defoaming agent containing a polymer having as at least a polymerization component a polymerizable monomer (A''') which is a compound represented by the following general formula (A-5): (In the above general formula (A-5), R １３ are each independently a hydrogen atom or a methyl group; R ５３ are each independently an alkyl group having 1 to 6 carbon atoms; R ５４ are each independently an alkyl group having 1 to 6 carbon atoms; １７ are each independently a divalent organic group which may have an ether bond, t is a repeating unit which is each independently an integer of 1 to 100, and u is a repeating unit which is an integer of 1 to 10.

6. A defoaming agent containing a polymer having as at least a polymerization component a polymerizable monomer (A'''') which is a compound represented by the following general formula (A-6): (In the above general formula (A-6), R １３ are each independently a hydrogen atom or a methyl group; R ５５ are each independently an alkyl group having 1 to 6 carbon atoms; １８ each independently represents a divalent organic group which may have an ether bond; and each v independently represents a repeating unit and is an integer of 1 to 100.

7. The defoaming agent according to any one of claims 1 to 6, wherein the contents of the polymerizable monomer (A), the polymerizable monomer (A'), the polymerizable monomer (A"), the polymerizable monomer (A'"), and the polymerizable monomer (A"") in the polymerization components are in the ranges of 5 to 75 mass%.

8. The defoaming agent according to any one of claims 1 to 6, wherein the polymerization component further contains a polymerizable monomer (B) having one or more groups selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, an aromatic group having 6 to 18 carbon atoms, a group containing a polyoxyalkylene chain, and a group containing a polyester chain, and having one polymerizable unsaturated group.

9. The defoaming agent according to claim 8, wherein the polymerizable monomer (B) is one or more selected from the group consisting of compounds represented by the following general formulas (B-1) to (B-10): (In the above general formulae (B-1), (B-2), (B-3), (B-4), (B-5), (B-6), (B-7), (B-8), (B-9) and (B-10), R ２１ is a hydrogen atom or a methyl group; R ２２ is an alkyl group having 1 to 18 carbon atoms; R ２３ is a hydrogen atom or a methyl group; R ２４ is a hydrogen atom or an alkyl group having 1 to 18 carbon atoms; R ２５ is a hydrogen atom or a methyl group; R ２６ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond; R ２７ is a hydrogen atom or a methyl group; R ２８ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or an alkyl group having 1 to 18 carbon atoms and an ether bond; R ２９ is a hydrogen atom or a methyl group; R ３０ are each independently an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms; R ３１ ~R ３５ each independently represents a hydrogen atom or a methyl group; １９ and L ２０ each independently represents a divalent organic group which may have an ether bond or a single bond; ２１ and L ２２ each independently represents a divalent organic group which may have an ether bond or a single bond; ２３ represents an organic group having a valence of r1+1 which may have an ether bond or a single bond; ２４ is an organic group having a valence of r2+r3 and which may have an ether bond and / or an ester bond; L ２５ is an organic group having a valence of 4+1 and may have an ether bond; L ２６ is a single bond or an organic group having a valence of r5+1 which may have an ether bond; ２７ is an organic group or a single bond which may have an ether bond having a valence of r6+1, m represents the number of repetitions, and the number average value of m is in the range of 1 to 200, p is an integer in the range of 1 to 10, q represents the number of repetitions, and the number average value of q is in the range of 1 to 100, l is an integer in the range of 0 to 5, r2 and r3 represent the number of repetitions, and are integers in the range of 1 to 3, and r1, r4, r5, and r6 represent the number of repetitions, and are 2 or 3.

10. The defoaming agent according to claim 9, wherein the polymerizable monomer (B) includes the compounds represented by the general formulas (B-2), (B-7) and (B-8).

11. The defoaming agent according to claim 8, wherein the content of the polymerizable monomer (B) in the polymerization components is in the range of 5 to 75 mass %.

12. The defoaming agent according to any one of claims 1 to 6, wherein the polymerization components further contain a polymerizable monomer (C) having two or more polymerizable unsaturated groups other than the polymerizable monomer (A), the polymerizable monomer (A'), the polymerizable monomer (A''), the polymerizable monomer (A'''), and the polymerizable monomer (A'''').

13. The defoaming agent according to claim 12, wherein the polymerizable monomer (C) is a compound represented by the following general formula (C-1): (In the general formula (C-1), R ３６ is a hydrogen atom or a methyl group; r is an integer of 2 or more; L ３１ is an organic group which may have an ether bond having a valence of r.

14. The defoaming agent according to claim 12, wherein the content of the polymerizable monomer (C) in the polymerization components is in the range of 5 to 70 mass %.

15. The defoaming agent according to any one of claims 1 to 6, wherein the weight average molecular weight of the polymer is in the range of 2,000 to 200,000.

16. The defoaming agent according to claim 1, which contains a polymerizable monomer (D) in which the number of polymerizable unsaturated groups in the polymerizable monomer (A) is one.

17. The defoaming agent according to claim 16, wherein the polymerizable monomer (D) is a compound represented by the following general formula (D-1): (In the general formula (D-1), R ４１ each independently represents an alkyl group having 1 to 6 carbon atoms or —OSi(R ４４ ) ３ A group represented by R ４４ each independently represents an alkyl group having 1 to 3 carbon atoms; R ４２ are each independently an alkyl group having 1 to 6 carbon atoms; R ４３ is an alkyl group having 1 to 12 carbon atoms; R ４５ is a hydrogen atom or a methyl group; L ４１ is a divalent organic group which may have an ether bond, and s represents the number of repetitions.

18. A lubricating oil composition comprising a lubricating base oil and the antifoaming agent according to any one of claims 1 to 6.

19. The lubricating oil composition according to claim 18, which is used to lubricate the driving parts of a machine having an internal combustion engine or an electric motor.

20. The lubricating oil composition of claim 18 for use in lubricating the driving parts of a motor vehicle having an internal combustion engine or an electric motor.

21. A machine in which the lubricating oil composition according to claim 18 is used in a drive part.

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