Defoaming agent, lubricating oil composition containing the defoaming agent, and machine using the lubricating oil composition

Abstract

Provided is an antifoaming agent that exhibits excellent defoaming properties even in a high-temperature environment. -[OSi(R)2] x -(R is independently an alkyl group having 1 to 6 carbon atoms each. x is the number of repetitions.) A polymerizable monomer (a1) having a polysiloxane structure represented by and / or -Si[OSi(R)3] n [R’] 3-n (n is an integer from 1 to 3. 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 each) An antifoaming agent containing a polymer having at least a polymerizable monomer (A) as a polymerizable component, which is a polymerizable monomer (a2) having a functional group represented by and having two or more polymerizable unsaturated groups.

Description

Technical Field

[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.

Background Art

[0002] In recent years, reduction of carbon dioxide emissions has become an important theme in the industrial world. Among them, the carbon dioxide emissions of transportation equipment including automobiles account for nearly 20% of the total. As one of the countermeasures to reduce this, switching from gasoline vehicles to electric vehicles (EVs) has been adopted as the policy of each country.

[0003] The most important issue in EVs is improvement of fuel efficiency (electricity cost). For this purpose, studies such as downsizing of the vehicle body and high efficiency of the drive system are being advanced at a rapid pace. One of the issues of high efficiency of the drive system is foaming of the lubricating oil. The lubricating oil is being made lower in viscosity to reduce frictional resistance, but this lower viscosity makes it easier to foam.

[0004] When high-load operation and high-speed driving are continuously performed, foaming increases in the low-viscosity lubricating oil, and the lubricating performance and cooling efficiency decrease due to foaming; wear and seizure occur due to breakage of the oil film at the friction part; problems such as acceleration of deterioration of the lubricating oil due to an increase in the oil temperature may occur.

[0005] Therefore, a lubricating oil having high antifoaming properties is required so that foaming can be suppressed from the initial stage of operation over a long period, and the lubricating oil contains an antifoaming agent for preventing foaming. As the antifoaming agent, polysiloxane-based antifoaming agents are known, and various polysiloxane-based antifoaming agents have been proposed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] Conventional polysiloxane-based antifoaming agents have a problem that their antifoaming properties significantly decrease with an increase in temperature. For example, in automotive applications where antifoaming properties at high temperatures are required, sufficient antifoaming properties cannot be obtained.

[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. [Means for Solving the Problems]

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that a polymer having at least a polymerizable monomer (a1) having a specific silicone functional group and two or more polymerizable unsaturated groups as a polymerization component exhibits excellent antifoaming properties even in a high-temperature environment, and completed the present invention.

[0010] That is, the present invention relates to the following antifoaming agents and the like. [1] -[OSi(R)2] x -(R is independently an alkyl group having 1 to 6 carbon atoms. x is the number of repetitions.) A polymerizable monomer (a1) having a polysiloxane structure and 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. R is independently an alkyl group having 1 to 6 carbon atoms. R’ is independently an alkyl group having 1 to 6 carbon atoms) An antifoaming agent containing a polymer having at least a polymerizable monomer (A) having a functional group represented by and having two or more polymerizable unsaturated groups as a polymerization component. [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). [Chemical formula] (In the general formula (A-1) and the general formula (A-2), R 11 is independently an alkyl group having 1 to 6 carbon atoms, R 12 is independently an alkyl group having 1 to 6 carbon atoms, R 13 is independently a hydrogen atom or a methyl group, R 14 is an alkyl group having 1 to 12 carbon atoms, R 15 is independently an alkyl group having 1 to 6 carbon atoms or a group represented by -OSi(R 16 )3 (R 16 is independently an alkyl group having 1 to 6 carbon atoms), x represents the number of repetitions, y is an integer of 1 or more, z1 and z2 are independently integers of 1 or more, z3 is an integer of 2 or more, L 11 is an organic group which may have a z1+1-valent ether bond, L 12 is an organic group which may have a z2+1-valent ether bond, L 13 is an organic group which may have a z3+y-valent ether bond, L 14 is a divalent organic group which may have an ether bond or a single bond. ) [3] A defoaming agent containing a polymer having at least a polymerizable monomer (A') represented by the following general formula (A-3) as a polymerization component. [Chemical formula] (In the general formula (A-3), R 13 is, independently of each other, a hydrogen atom or a methyl group, R 51 is, independently of each other, an alkyl group having 1 to 6 carbon atoms, L 15 is a divalent organic group which may have an ether bond, a is a repeating unit and is an integer of 0 to 3) [4] An antifoaming agent containing a polymer having at least a polymerizable monomer (A'') represented by the following general formula (A-4) as a polymerization component. [Chemical formula] (In the general formula (A-4), R 13 is, independently of each other, a hydrogen atom or a methyl group, R 52 is, independently of each other, an alkyl group having 1 to 6 carbon atoms, L 16 is, independently of each other, a divalent organic group which may have an ether bond) [5] An antifoaming agent containing a polymer having at least a polymerizable monomer (A''') represented by the following general formula (A-5) as a polymerization component. [Chemical formula] (In the general formula (A-5), R 13 is, independently of each other, a hydrogen atom or a methyl group, R 53 is, independently of each other, an alkyl group having 1 to 6 carbon atoms, R 54 is, independently of each other, an alkyl group having 1 to 6 carbon atoms, L 17 is, independently of each other, a divalent organic group which may have an ether bond, t is a repeating unit and is, independently of each other, an integer of 1 to 100, u is a repeating unit and is an integer of 1 to 10) [6] An antifoaming agent containing a polymer having at least a polymerizable monomer (A'''') represented by the following general formula (A-6) as a polymerization component. [Chemical formula] (In the general formula (A-6), R 13 is independently a hydrogen atom or a methyl group, R 55 is independently an alkyl group having 1 to 6 carbon atoms, L 18 is independently a divalent organic group which may have an ether bond, v is a repeating unit and is independently an integer of 1 to 100) [7] The antifoaming agent according to any one of [1] to [6], wherein the contents of the polymerizable monomer (A), polymerizable monomer (A'), polymerizable monomer (A''), polymerizable monomer (A'''), and polymerizable monomer (A'''') in the polymerization component are in the range of 5 to 75% by mass. [8] The antifoaming agent according to any one of [1] to [7], wherein the polymerization component further contains a polymerizable monomer (B) having one polymerizable unsaturated group and having at least one 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. [9] The antifoaming agent according to [8], wherein the polymerizable monomer (B) is at least one selected from the group consisting of compounds represented by the following (B-1) to (B-10). [Chemical formula] [Chemical formula] (In the general formulas (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 22is 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 an ether bond of 1 to 18 carbon atoms, 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 an ether bond of 1 to 18 carbon atoms, 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, L 19 and L 20 are each independently a divalent organic group which may have an ether bond or a single bond, L 21 and L 22 are each independently a divalent organic group which may have an ether bond or a single bond, L 23 is an organic group which may have an r1 + 1-valent ether bond or a single bond, L 24 is an organic group which may have an r2 + r3-valent ether bond and / or an ester bond, L 25 is an organic group which may have an r4 + 1-valent ether bond, L 26 is an organic group which may have an r5 + 1-valent ether bond or a single bond, L 27is an organic group or a single bond which may have an r6+1-valent ether bond, m represents the number of repetitions, 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, 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) contains the compounds represented by the 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 component is in the range of 5 to 75% by mass.

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

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

Chemical formula

[14] The defoaming agent according to

[12] or

[13] , wherein the content of the polymerizable monomer (C) in the polymerization component is in the range of 5 to 70% by 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) having one polymerizable unsaturated group of the polymerizable monomer (A).

[17] The defoaming agent according to

[16] , wherein the polymerizable monomer (D) is a compound represented by the following general formula (D-1). [Chemical formula] (In the general formula (D-1), R 41 is each independently an alkyl group having 1 to 6 carbon atoms or a group represented by -OSi(R 44 )3 (R 44 is each independently an alkyl group having 1 to 3 carbon atoms), R 42 is 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, s represents the number of repetitions.)

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

[17] .

[19] In a machine equipped with an internal combustion engine or an electric motor, the lubricating oil composition according to

[18] , which is used for lubricating the driving part of the machine.

[20] In an automobile equipped with an internal combustion engine or an electric motor, the lubricating oil composition according to

[18] , which is used for lubricating the driving part of the automobile.

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

[18] to

[20] for the driving part. [Advantages of the Invention]

[0011] According to the present invention, a defoaming agent showing excellent defoaming properties even in a high-temperature environment can be provided. According to the present invention, a lubricating oil composition capable of showing excellent lubricating performance even in a high-temperature environment can be provided. [Embodiments for Carrying out the Invention]

[0012] Hereinafter, an embodiment of the present invention will be described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications 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 may be derived from biological resources. In this specification, "(meth)acrylate" means one or both of acrylate and methacrylate.

[0013] [Defoaming agent] The defoaming agent of the present invention is -[OSi(R)2] x -(R is each independently an alkyl group having 1 to 6 carbon atoms. x is the number of repetitions.) It has a polysiloxane structure represented by, and contains a polymer having at least 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 from 1 to 3. R is each independently an alkyl group having 1 to 6 carbon atoms. R’ is each independently an alkyl group having 1 to 6 carbon atoms) It contains a polymer having a functional group represented by and having at least a polymerizable monomer (a2) having two or more polymerizable unsaturated groups as a polymerizable component. Here, the "polymerizable component" means a component constituting the polymer, and does not include solvents, polymerization initiators, etc. that do not constitute the polymer.

[0014] In the present invention, the "polymerizable monomer" means a compound having a polymerizable unsaturated group. Examples of the polymerizable unsaturated group of the polymerizable monomer (A) include (meth)acryloyl group, (meth)acryloyloxy group, (meth)acrylamide group, vinyl ether group, allyl group, styryl group, (meth)acrylamino group, maleimide group, etc.

[0015] The polymer having at least the polymerizable monomer (A) contained in the defoaming agent of the present invention as a polymerizable component may be referred to as the "polymer of the present invention". Hereinafter, each component constituting the polymer of the present invention will be described below.

[0016] -[OSi(R)2] possessed by the polymerizable monomer (A) x The polysiloxane structure represented by - is preferably a polydimethylsiloxane structure. -Si[OSi(R)3] possessed by the polymerizable monomer (A) n [R’] 3-n The functional group represented by is preferably a functional group represented by -Si[OSi(R)3]3, more preferably -Si[OSi(CH3)3]3.

[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]

Chemical formula

[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), and is a compound in which P is a polymerizable group represented by the general formula (P-1), and is represented by the following general formula.

[0020]

Chemical formula

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

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

[0023] The repeating number 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 still more preferably in the range of 1 to 20. The number average value 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 still more preferably 1.

[0025] L 11 Regarding the organic group which may have a z1+1-valent ether bond of L, for example, when L 11 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 11 Examples of the alkylene group having 1 to 50 carbon atoms of L include methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, n-dodecylene group, isopropylene group, 2-methylpropylene group, 2-methylhexylene group, tetramethylethylene group and the like.

[0027] L 11The 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 still more preferably a methylene group, an ethylene group, an n-propylene group or an isopropyl group.

[0028] L 11 The alkyleneoxy group having 1 to 50 carbon atoms is, for example, a group in which one or more -CH2- in the above alkylene group are replaced by -O-. L 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 still 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, a part of -CH2- in these divalent organic groups may be replaced by a carbonyl group (-C(=O)-), a phenylene group, an amide bond, a sulfide bond (-S-), 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, these groups may be further substituted with a substituent such as a hydroxyl group on the carbon atoms.

[0031] L 11 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 by a bond so as to have the 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 still more preferably 1.

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

[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 still 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 still more preferably 2.

[0036] L 13 The z3 + y-valent organic group of can be the same as the organic group of the corresponding valence of the z1 + 1-valent organic group of L 11 of L 13 For example, when L 13 is a trivalent organic group, the trivalent organic group of the said L 13 may be the same as the trivalent organic group of L 11

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

[0038] The defoaming agent of the present invention may be an embodiment containing a polymer having at least the following polymerizable monomer (A'), polymerizable monomer (A''), polymerizable monomer (A'''), and polymerizable monomer (A'''') as polymerization components, in addition to the above polymerizable monomer (A). Hereinafter, these embodiments will be described.

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

[0040] ​​​ [Chemical formula] (In the general formula (A-3), R 13 is independently a hydrogen atom or a methyl group, R 51 is independently an alkyl group having 1 to 6 carbon atoms, L 15 is a divalent organic group which may have an ether bond, a is 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, the adjacent Si and O are bonded to form a cyclic siloxane compound having three (meth) acrylate groups. As a increases to 2 or 3, the -Si-O- of the cyclic siloxane structure also increases. When a is 2, it is a compound having five (meth) acrylate groups, and when a is 3, it is a compound having six (meth) acrylate groups.

[0042] L 15 The divalent organic group of is the same as the above L 11 and is 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 the general formula (A-3) include compounds represented by the following formulas (A-3-1), (A-3-2), (A-3-3), (A-3-4), (A-3-5), and (A-3-6).

[0044] [Chemical formula]

[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]

Chem.

[0047] R 52 is preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group. L in the general formula (A-4) 16 is the same as L 15 in the general formula (A-3), and is 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 formulas (A-4-1) and (A-4-2).

[0049]

Chem.

[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]

Chem.

[0052] R 53 and R 54 are preferably alkyl groups having 1 to 3 carbon atoms, more preferably methyl groups. 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 still more preferably in the range of 0 to 20. u is preferably 1 to 4, more preferably 1 to 2. L in the general formula (A-5) 17 is the same as L in the general formula (A-3) 15 and is 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 the general formula (A-5) include the compounds represented by the formulas (A7), (A8), (A9), and the following formulas (A7’), (A8’), and (A9’) described in Synthesis Example 7 below (t1, t2, and t3 in the formulas are, independently of each other, integers of 0 to 7).

[0054]

Chemical formula

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

[0056]

Chemical formula

[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. L in the general formula (A-6) 18 is the same as L in the general formula (A-3) 15 and is 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 the compound represented by the formula (A10) described in Synthesis Example 8 below and the following formula (A10’).

[0059]

Chemical formula

[0060] The polymerizable monomer (A) can be produced by a known method. For example, the polymerizable monomer (A) is -[OSi(R)2] x - represented linking group and / or -Si[OSi(R)3] n [R’] 3-n It can be produced by reacting a compound having a functional group represented by and two or more hydroxyl groups with a compound having an isocyanate group and a polymerizable unsaturated group. In addition to the above, the polymerizable monomer (A) is, for example, -[OSi(R)2] x - represented linking group and / or -Si[OSi(R)3] n [R’] 3-nA compound having a functional group and a polymerizable unsaturated group represented by the formula is reacted with an alcohol having a mercapto group to form a precursor, and the precursor is reacted with a compound having an isocyanate group and two or more polymerizable unsaturated groups, whereby it can also be produced. The above-mentioned polymerizable monomer (A'), polymerizable monomer (A''), polymerizable monomer (A'''), and polymerizable monomer (A'''') can also be produced in the same manner as the polymerizable monomer (A).

[0061] In the polymer of the present invention, the lower limit of the content ratio 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 with respect to the total amount of the polymerization components of the polymer. The upper limit of the content ratio 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 with respect to the total amount of the polymerization components of the polymer. Examples of the combination of the upper and lower limits of the content ratio of the polymerizable monomer (A) include, for example, a range of 3% by mass to 90% by mass of the total amount of the polymerization components of the polymer, preferably a range of 5% by mass to 75% by mass of the total amount of the polymerization components of the polymer, and more preferably 30% by mass to 70% by mass. The content ratio of the polymerizable monomer (A) can be adjusted by the raw material charging ratio of the polymerizable monomer (A) when producing the polymer of the present invention. The above-mentioned polymerizable monomer (A'), polymerizable monomer (A''), polymerizable monomer (A'''), and polymerizable monomer (A'''') are also in the same ratio as the polymerizable monomer (A).

[0062] The polymerization components of the polymer of the present invention preferably have one or more 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 further contain a polymerizable monomer (B) 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 the 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 that the polymerizable monomer (B) has may be any of a linear alkyl group, a branched alkyl group, and a cyclic alkyl group. Specific examples 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, and the like. The alkyl group having 1 to 18 carbon atoms that the polymerizable monomer (B) has is preferably an alkyl group having 1 to 6 carbon atoms.

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

[0065] The group containing a (poly)oxyalkylene chain that the polymerizable monomer (B) has is a monovalent group containing a repeating portion of oxyalkylene or a divalent linking group containing a repeating portion of oxyalkylene.

[0066] The group containing a polyester chain that the polymerizable monomer (B) has is a monovalent group containing a repeating portion of an ester bond or a divalent linking group containing a repeating portion of an ester bond.

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

[0068] Examples of the polymerizable monomer (B) having an alkyl group with 1 to 18 carbon atoms and a polymerizable unsaturated group being a (meth)acryloyl group include alkyl esters of (meth)acrylic acid with 1 to 18 carbon atoms such as 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, dodecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate; bridged cyclic alkyl esters of (meth)acrylic acid with 1 to 18 carbon atoms such as dicyclopentyloxyethyl (meth)acrylate, isobornyloxyethyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, dimethyladamantyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, etc. In the present application, "(meth)acrylate" means both methacrylate and acrylate.

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

[0070] Examples of the polymerizable monomer (B) having an alkyl group with 1 to 18 carbon atoms and a polymerizable unsaturated group being 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, cyclohexyl vinyl ether; cycloalkyl vinyl ethers and the like.

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

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

[0073] Examples of the polymerizable monomer (B) having an alkyl group with 1 to 18 carbon atoms and a polymerizable unsaturated group being a maleimide group include methyl maleimide, ethyl maleimide, propyl maleimide, butyl maleimide, hexyl maleimide, octyl maleimide, dodecyl maleimide, stearyl maleimide, cyclohexyl maleimide and the like.

[0074] Examples of the polymerizable monomer (B) having a group containing a polyoxyalkylene chain and having a polymerizable unsaturated group that 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·poly1,2-butylene glycol mono(meth)acrylate, poly(tetraethylene glycol·1,2-butylene glycol) mono(meth)acrylate, polytetraethylene glycol·poly1,2-butylene glycol mono(meth)acrylate, poly1,2-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, poly1,2-Butylene glycol·polytetramethylene 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, poly 1,2-butylene glycol·polytetramethylene glycol mono(meth)acrylate and the like can be mentioned., In addition, the above-mentioned "poly(ethylene glycol·propylene glycol)" means a random copolymer of ethylene glycol and propylene glycol, and "polyethylene glycol·polypropylene glycol" means 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] [Chemical formula] [Chemical formula] (In the general formulas (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, R24 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 an ether bond with 1 to 18 carbon atoms, 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 an ether bond with 1 to 18 carbon atoms, 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, L 19 and L 20 are each independently a divalent organic group which may have an ether bond or a single bond, L 21 and L 22 are each independently a divalent organic group which may have an ether bond or a single bond, L 23 is an organic group which may have an r1 + 1-valent ether bond or a single bond, L 24 is an organic group which may have an r2 + r3-valent ether bond and / or an ester bond, L 25 is an organic group which may have an r4 + 1-valent ether bond, L 26 is an organic group which may have an r5 + 1-valent ether bond or a single bond, L 27 is an organic group which may have an r6 + 1-valent ether bond or a single bond, m represents the number of repetitions, 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, 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, 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 as or different from each other. In the formula (B-3), the q p's in the parentheses may be the same as or different from each other. In the formula (B-4), the q p's in the parentheses may be the same as or different from each other. In the formula (B-8), the m m's in the parentheses may be the same as or different from each other. In the formula (B-9), the q p's in the parentheses may be the same as or different from each other. In the formula (B-10), the q p's in the parentheses may be the same as or different from each other.

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

[0079] The L of the formulas (B-1) to (B-4) 19 ~L22 The divalent organic group is L 11 When L is a divalent organic group, the same ones as those described above can be mentioned. L in the formulas (B-6) to (B-10) 23 ~L 27 The divalent organic groups are the same.

[0080] In the general formulas (B-2) and (B-8), m represents the number of repetitions. For example, m may be an integer of 1 or more. 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 value 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 formulas (B-3), (B-4), (B-9) and (B-10), q represents the number of repetitions. For example, q may be an integer of 1 or more. 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 formulas (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 contains the compounds represented by the formulas (B-2), (B-7) and (B-8).

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

[0085] The polymerizable monomer (B) as the polymerization component may be a single 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 commercially available products may also be used.

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

[0088] In the polymer of the present invention, the ratio of the polymerizable monomer (B) in the polymerization component is, for example, in the range of 5 to 90% by mass, preferably 10 to 80% by mass, more preferably 20 to 70% by mass, and particularly preferably 30 to 60% by 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 include, as optional components, 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'''').

[0090] The polymerizable monomer (C) is not particularly limited as long as it is a polymerizable monomer having two or more polymerizable unsaturated groups that do not correspond to the polymerizable monomer (A) and the polymerizable monomer (B), but is preferably a compound represented by the following general formula (C-1).

[0091] [Chemical formula] (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 that 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 still more preferably an integer in the range of 2 to 4.

[0093] L 31 The r-valent organic group of is an organic group having a valence corresponding to the 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 and the alkyleneoxy group is replaced with a bond so as to have a valence corresponding to the value of r. Therefore, when L 31 is a divalent organic group, L 31is 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 of L 31 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, a tetramethylethylene group, and the like.

[0096] L 31 The alkylene group having 1 to 50 carbon atoms of L 31 is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and still 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 of L 31 is, for example, a group in which one or more -CH2- in the above alkylene group are replaced by -O-. L 31 The alkyleneoxy group having 1 to 50 carbon atoms of L 31 is preferably an alkyleneoxy group having 1 to 15 carbon atoms, more preferably an alkyleneoxy group having 1 to 8 carbon atoms, and still 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 of L 31 is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, a part of these divalent organic groups 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 31When 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 groups may be further substituted with substituents such as hydroxyl groups on the carbon atoms.

[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 - methacryloylpropyl acrylate, 2 - hydroxy - 1,3 - dimethacryloxypropane, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, ethoxylated bisphenol 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, polypentaerythritol poly(meth)acrylate, and the like.

[0101] The polymerizable monomer (C) as the polymerization component may be used alone or may be two or more polymerizable monomers (C) having different structures from each other.

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

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

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

[0105] The polymerization components of the polymer of the present invention may include a polymerizable monomer (D) having one polymerizable unsaturated group in the polymerizable monomer (A).

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

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

[0108] L 41 The divalent organic group of 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 of L 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, a tetramethylethylene group and the like.

[0110] L 41 The alkylene group having 1 to 50 carbon atoms of L is preferably an alkylene group having 1 to 15 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms, and still 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 of L is, for example, a group in which one -CH2- in the above alkylene group is replaced by -O-. L 41 The alkyleneoxy group having 1 to 50 carbon atoms of L is preferably an alkyleneoxy group having 1 to 15 carbon atoms, more preferably an alkyleneoxy group having 1 to 8 carbon atoms, and still 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 41When the divalent organic group is an alkylene group having 1 to 50 carbon atoms or an alkyleneoxy group having 1 to 50 carbon atoms, in these divalent organic groups, a part of -CH2- may be replaced by a carbonyl group (-C(=O)-), a phenylene group, an amide bond or a urethane bond, and further, a hydroxyl group or the like may be substituted on the carbon atom.

[0113] The repeating number 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 still more preferably in the range of 1 to 25. The number average value 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 of R is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. R 43 The alkyl group having 1 to 12 carbon atoms of R is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.

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

[0116] The polymerizable monomer (D) as the polymerization component may be used alone or in combination of two or more.

[0117] In the polymer of the present invention, the content ratio of the polymerizable monomer (D) is, for example, in the range of 10 to 500 parts by mass with respect to 100 parts by mass of the polymerizable monomer (A), preferably in the range of 30 to 400 parts by mass with respect to 100 parts by mass of the polymerizable monomer (A), and more preferably in the range of 50 to 300 parts by mass with respect to 100 parts by mass of the polymerizable monomer (A). The content ratio 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 having the polymerizable monomer (A), an arbitrary polymerizable monomer (B), and an arbitrary polymerizable monomer (C) as polymerization components, and may contain other polymerizable monomers other than the polymerizable monomer (A), the arbitrary polymerizable monomer (B), and the arbitrary polymerizable monomer (C) as polymerization components as long as the effects of the present invention are not impaired. Examples of the other polymerizable monomers as polymerization components include the above-mentioned polymerizable monomer (D). The polymer of the present invention is preferably a polymer substantially composed of the polymerizable monomer (A) and an arbitrary polymerizable monomer (B) and / or an arbitrary polymerizable monomer (C) as polymerization components, and more preferably a copolymer composed only of the polymerizable monomer (A), an arbitrary polymerizable monomer (B), and / or an arbitrary polymerizable monomer (C) as polymerization components. Here, "substantially composed of" means that the total content ratio of the polymerizable monomer (A), the arbitrary polymerizable monomer (B), and the arbitrary 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 form 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), an arbitrary polymerizable monomer (B), and an arbitrary polymerizable monomer (C). Further, the polymer of the present invention may be, for example, a block polymer having one or more polymer blocks of the polymerizable monomer (A), an arbitrary polymerizable monomer (B), and an arbitrary polymerizable monomer (C).

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

[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 the number average molecular weight (Mn) are values converted to polystyrene based on gel permeation chromatography (GPC) measurement. The values of the number average molecular weight (Mn) and the weight average molecular weight (Mw) 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 the polymer of the present invention, and may also contain a defoaming agent other than the polymer of the present invention. Further, 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 it 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, etc. based on a polymerization mechanism such as a radical polymerization method, a cationic polymerization method, an anionic polymerization method. For example, in the case of a radical polymerization method, a polymerizable monomer mixture is charged into an organic solvent, and a general radical polymerization initiator is added to produce the polymer of the present invention.

[0125] As the polymerization initiator, various ones can be used. For example, peroxides such as t-butyl peroxy-2-ethylhexanoate, benzoyl peroxide, and diacyl peroxide; azo compounds such as azobisisobutyronitrile, dimethyl azobisisobutyrate, and phenylazotriphenylmethane; metal chelate compounds such as Mn(acac)3, etc. can be mentioned. If necessary, chain transfer agents such as lauryl mercaptan, 2-mercaptoethanol, ethylthioglycolic acid, octylthioglycolic acid, etc., and thiol compounds having a coupling group such as γ-mercaptopropyltrimethoxysilane may be used as additives such as chain transfer agents.

[0126] Examples of the organic solvent include alcohols such as ethanol, isopropyl alcohol, n-butanol, iso-butanol, tert-butanol, etc.; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl amyl ketone, etc.; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, butyl lactate, etc.; 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, butyl 2-methoxypropionate, etc.; polar solvents such as dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, etc.; ethers such as methyl cellosolve, cellosolve, butyl cellosolve, butyl carbitol, ethyl cellosolve acetate, etc.; propylene glycols and their esters such as propylene glycol, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, etc.; halogenated solvents such as 1,1,1-trichloroethane, chloroform, etc.; ethers such as tetrahydrofuran, dioxane, etc.; aromatics such as benzene, toluene, xylene, etc.; and further fluorinated inert liquids such as perfluorooctane, perfluorotri-n-butylamine, etc. 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 and living anionic polymerization.

[0128] In living radical polymerization, a dormant species in which the active polymerization terminal is protected by an atom or atomic group reversibly generates a radical and reacts with a monomer, so that the growth reaction proceeds. Even when the first monomer is consumed, the growth terminal does not lose its activity and reacts with the second monomer added sequentially to obtain a block polymer. Examples of such living radical polymerization include atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer polymerization (RAFT), nitroxide-mediated radical polymerization (NMP), radical polymerization using organic tellurium (TERP), etc. Among these, there is no particular restriction on which method to use, but ATRP is preferred because of its ease of control. ATRP is polymerized using 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 the polymerization initiator 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 alkyl esters of 2-halocarboxylic acids having 1 to 6 carbon atoms (such as methyl 2-chloropropionate, ethyl 2-chloropropionate, methyl 2-bromopropionate, ethyl 2-bromoisobutyrate, etc.). More specific examples of the alkyl esters of 2-halocarboxylic acids having 1 to 6 carbon atoms include, for example, methyl 2-chloropropionate, ethyl 2-chloropropionate, methyl 2-bromopropionate, ethyl 2-bromoisobutyrate, etc.

[0130] The transition metal compound that can be used in ATRP is Mn+ X n is represented by M n+ X n The transition metal M of the transition metal compound represented by n+ is, for example, Cu + 、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+ and can be selected from the group consisting of. M n+ X n In the transition metal compound represented by, X is a halogen atom, an alkoxyl group having 1 to 6 carbon atoms, (SO4) 1 / 2 , (PO4) 1 / 3 , (HPO4) 1 / 2 , (H2PO4), triflate, hexafluorophosphate, methanesulfonate, arylsulfonate (preferably benzenesulfonate or toluenesulfonate), SeR 11 , CN and R 12 COO and can be selected from the group consisting of. Here, R 11 represents an aryl group, a linear or branched alkyl group having 1 to 20 carbon atoms (preferably 1 to 10 carbon atoms), R 12represents a linear or branched alkyl group having 1 to 6 carbon atoms (preferably a methyl group) which may be substituted with a hydrogen atom or a halogen 1 to 5 times (preferably 1 to 3 times with fluorine or chlorine). M n+ X n For the transition metal compound represented by, n represents the formal charge on the metal and is an integer from 0 to 7.

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

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

[0133] Specific examples of the catalyst that can be used in ATRP include, when the central metal is copper, complexes with ligands such as 2,2'-bipyridyl and its derivatives, 1,10-phenanthroline and its derivatives, polyamines such as tetramethylethylenediamine, pentamethyldiethylenetriamine, hexamethyltris(2-aminoethyl)amine. 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, carbonylchlorohydridotris(triphenylphosphine)ruthenium. Further examples of divalent iron complexes include bis(triphenylphosphine) complexes, triazacyclononane complexes.

[0134] In living radical polymerization, it is preferable to use a solvent. Examples of the solvent 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; halogen 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 derived from the transition metal compound used in the polymerization may remain in the obtained polymer. The metal remaining in the obtained polymer may be removed using activated alumina or the like after the polymerization is completed.

[0137] [Lubricating oil composition] The defoaming agent of the present invention can be suitably used as a defoaming agent for lubricating oil compositions, and the lubricating oil composition of the present invention contains the defoaming 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 the spread of the molecules of the defoaming agent even in a high-temperature environment and maintain a low solubility in the lubricating base oil. Thereby, the defoaming agent of the present invention can exhibit high defoaming performance even in a high-temperature environment. In addition, in a machine equipped with an internal combustion engine or an electric motor, although a high shearing force is applied to the drive unit of the machine, since the defoaming agent of the present invention suppresses the reduction in molecular weight due to its cross-linked structure, it is possible to suppress a decrease in defoaming performance.

[0139] The defoaming agent of the present invention has high defoaming performance as described above, and can be used without limitation in lubricating oil compositions for drive system devices such as automotive shock absorbers, transmissions, and power steering.

[0140] The content ratio of the defoaming 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 mass ppm, preferably in the range of 5 to 700 mass ppm, and more preferably in the range of 10 to 400 mass ppm, based on the total amount of the lubricating oil composition.

[0141] As the base oil of the lubricating oil composition of the present invention, known ones can be used, which may be mineral oil, synthetic oil, or a mixed oil of mineral oil and synthetic oil.

[0142] Examples of mineral oil include mineral oil obtained by subjecting a lubricating oil fraction obtained by vacuum distillation of an atmospheric residue obtained by atmospheric distillation of crude oil to one or more treatments such as solvent dewaxing, solvent extraction, hydrocracking, solvent deoiling, catalytic deoiling, and hydrorefining, and paraffinic mineral oil, naphthenic mineral oil, and the like can be mentioned. In addition, mineral oil produced by isomerizing mineral oil waxes or waxes (GTL waxes) produced by the Fischer-Tropsch method or the like can also be mentioned.

[0143] Examples of synthetic oil 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 ethers, polyglycols, alkylbenzenes, alkylnaphthalenes, and the like.

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

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

[0146] The base oil for lubricants preferably has a paraffin content (%Cp, which may sometimes be described as such) of 70% or more by n-d-M ring analysis, more preferably 75% or more, still more preferably 80% or more. When the paraffin content of the base oil for lubricants is within the above range, the oxidation stability and the like are improved.

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

[0148] The lubricant composition of the present invention may contain the antifoaming agent and the base oil for lubricants of the present invention, and may further contain other additives. Examples of the other additives may include additives such as 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 of two or more thereof.

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

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

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

[0152] Examples of the antiwear agent or extreme pressure agent include sulfur-containing compounds such as zinc dithiophosphate; phosphorus-containing compounds such as phosphite esters, phosphate esters, phosphonate esters, and amine salts or metal salts thereof; sulfur- and phosphorus-containing antiwear agents such as thiophosphite esters, thiophosphate esters, thiophosphonate esters, and amine salts or metal salts thereof.

[0153] Examples of the viscosity index improver include polymethacrylate, dispersed polymethacrylate, olefin copolymers (such as ethylene-propylene copolymers, etc.), dispersed olefin copolymers, styrene copolymers (such as styrene-diene copolymers, styrene-isoprene copolymers, etc.).

[0154] Examples of the metal deactivator include benzotriazole-based compounds, tolyltriazole-based compounds, imidazole-based compounds, pyrimidine-based compounds, etc.

[0155] Examples of the pour point depressant include ethylene-vinyl acetate copolymer, condensate of chlorinated paraffin and naphthalene, condensate of chlorinated paraffin and phenol, polymethacrylate, polyalkylstyrene, etc.

[0156] Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, polyhydric alcohol ester, and the like.

[0157] The lubricating oil composition of the present invention is suitably used for lubricating the driving part of a machine equipped with an internal combustion engine or an electric motor. Regarding the lubrication of the driving part, for example, in an electric vehicle, the driving part generally integrates a motor, an inverter, and a gearbox, and the inside of the gearbox can be lubricated by filling it with the lubricating oil composition of the present invention. Also, in the case of a gasoline vehicle, in the internal combustion engine which is the driving part, the lubricating oil composition of the present invention is stored in the oil pan and supplied into the cylinder via an oil pump, thereby lubricating the starting part. The lubrication of the driving part is not limited to these forms, and the driving part can be lubricated by filling, supplying, etc. the lubricating oil composition of the present invention to the part where metals contact each other.

[0158] As machines for which the lubricating oil composition of the present invention can be used, there are no restrictions as long as they are machines equipped with an internal combustion engine or an electric motor, such as automobiles (gasoline vehicles, electric vehicles), robots (industrial robots, entertainment robots), aircraft (airplanes, helicopters), ships, and various household appliances.

Examples

[0159] Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. Note that the present invention is not limited to the following Examples.

[0160] In Examples and Comparative Examples, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are values in terms of polystyrene conversion based on gel permeation chromatography (GPC) measurement. The measurement conditions of GPC are as follows. In the chemical formula, n represents an arbitrary repeating unit.

[0161] [GPC Measurement Conditions] Measuring device: High-speed GPC device "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: A solution obtained by dissolving 7.5 mg of the sample in 10 ml of tetrahydrofuran and filtering the resulting solution through a microfilter was used as the measurement sample. Sample injection volume: 20 μL Standard sample: The following monodisperse polystyrenes with known molecular weights were used in accordance with the measurement manual of 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 Antifoaming Agent (1)) 40 parts by mass of dipropylene glycol monomethyl ether acetate as a solvent was charged into a glass flask equipped with a stirrer, a thermometer, a condenser, and a dropping device, and the temperature was raised to 105°C while stirring under a nitrogen stream. Next, 25 parts by mass of a silicone dimethacrylate monomer represented by the following general formula (A1) (number average molecular weight: 1,000; n in the formula is a repeating unit), 25 parts by mass of methoxypolyethylene glycol acrylate (the number of repeating units of the ethylene oxide chain is about 9), and a monomer solution dissolved in 140 parts by mass of dipropylene glycol monomethyl ether acetate, and 7.5 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator dissolved in 20 parts by mass of dipropylene glycol monomethyl ether acetate were set in separate dropping devices, and while maintaining the inside of the flask at 105°C, they were simultaneously dropped over 2 hours. After completion of the dropping, the solution of the antifoaming agent (1) was obtained by stirring at 105°C for 4 hours.

[0164] [Chemical formula]

[0165] As a result of measuring the molecular weight of the obtained antifoaming agent (1) by GPC, the weight average molecular weight (Mw) was 13,300.

[0166] (Synthesis Example 2: Synthesis of Antifoaming Agent (2)) 30 parts by mass of dipropylene glycol monomethyl ether acetate as a solvent was charged into a glass flask equipped with a stirrer, a thermometer, a condenser, and a dropping device, and the temperature was raised to 110°C while stirring under a nitrogen stream. Next, 12.5 parts by mass of the silicone dimethacrylate monomer represented by the general formula (A1) (number average molecular weight: 1,000) and 12.5 parts by mass of polyethylene glycol dimethacrylate (the number of repeating units of the ethylene oxide chain is about 9) were dissolved in 60 parts by mass of dipropylene glycol monomethyl ether acetate to obtain a monomer solution. Separately, 7.5 parts by mass of t-butyl peroxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 10 parts by mass of dipropylene glycol monomethyl ether acetate to obtain a polymerization initiator solution. The two types of dropping solutions were each set in separate dropping devices, and while maintaining the inside of the flask at 110 °C, they were simultaneously dropped over 2 hours. After completion of the dropping, the solution of the defoaming agent (2) was obtained by stirring at 110 °C for 3 hours.

[0167] As a result of measuring the molecular weight of the obtained defoaming agent (2) by GPC, the weight average molecular weight (Mw) was 36,700.

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

[0169] [Chemical formula]

[0170] 30 parts by mass of butyl acetate was charged as a solvent into a glass flask equipped with a stirrer, a thermometer, a condenser, and a dropping device, and the temperature was raised to 100 °C while stirring under a stream of nitrogen. Next, 20 parts by mass of the silicone diacrylate monomer represented by the general formula (A3) and 20 parts by mass of methoxypolyethylene glycol acrylate (the number of ethylene oxide chain repetitions is about 9) were dissolved in 55 parts by mass of butyl acetate to form a monomer solution, and 2 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 10 parts by mass of butyl acetate to form a polymerization initiator solution. Two types of dropping liquids were each set in separate dropping devices, and while maintaining the inside of the flask at 100 °C, they were simultaneously dropped over 2 hours. After the dropping was completed, the solution of the defoaming agent (3) was obtained by stirring at 100 °C for 4 hours.

[0171] As a result of measuring the molecular weight of the obtained defoaming agent (3) by GPC, the weight average molecular weight (Mw) was 18,800.

[0172] (Synthesis Example 4: Synthesis of defoaming agent (4)) Into a glass flask equipped with a stirrer, thermometer, condenser, and dropping device, 215 parts by mass of the 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 part by mass of NaH were charged. Next, stirring was started under a nitrogen atmosphere, the temperature inside the flask was raised to 60 °C, and the mixture was stirred for 1.5 hours to obtain the silicone compound represented by the following general formula (A4-2).

[0173]

Chemical formula

[0174] Into a glass flask equipped with a stirring device, a thermometer, a cooling tube, and a dropping device, 50 parts by mass of the silicone compound represented by the general formula (A4-2), 40 parts by mass of heptane, and 0.1 part by mass of stannous octylate were charged. Next, stirring was started 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 completion of the dropping, the temperature was raised to 80 °C and stirring was carried out for 1 hour to conduct the reaction. As a result, disappearance of the absorption peak of the isocyanate group was confirmed by IR spectrum measurement. Thus, a silicone diacrylate monomer represented by the following general formula (A4) was obtained.

[0175] [Chemical formula]

[0176] 52 parts by mass of n-butyl acetate as a solvent was charged into a glass flask equipped with a stirring device, a thermometer, a cooling tube, and a dropping device, and the temperature was raised to 85 °C while stirring under a nitrogen stream. Next, a monomer solution in which 30 parts by mass of the silicone diacrylate monomer represented by the general formula (A4) and 20 parts by mass of methoxypolyethylene glycol methacrylate (the number of ethylene oxide chain repetitions is about 9) were dissolved in 50 parts by mass of butyl acetate, and 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 were set in separate dropping devices, and while maintaining the inside of the flask at 85 °C, they were simultaneously added dropwise over 2 hours. After completion of the dropping, stirring was carried out at 85 °C for 4 hours, then the temperature was raised to 110 °C, and further stirring was carried out for 1 hour to obtain a solution of the defoaming agent (4).

[0177] As a result of measuring the molecular weight of the obtained defoaming agent (4) by GPC, the weight average molecular weight (Mw) was 5,400.

[0178] (Synthesis Example 5: Synthesis of defoaming agent (5)) Into a glass flask equipped with a stirring device, a thermometer, a cooling tube, and a dropping device, 50 parts by mass of propylene glycol methyl ether acetate was charged as a solvent, and the temperature was raised to 105 °C while stirring under a nitrogen stream. Next, 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 units of the ethylene oxide chain is about 9), and 12.1 parts by mass of a silicone compound represented by the general formula (A4-1) were dissolved in 65 parts by mass of propylene glycol methyl ether acetate to obtain a monomer solution, and 7.1 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 10 parts by mass of propylene glycol methyl ether acetate to obtain a polymerization initiator solution. Two types of dropping liquids were set in separate dropping devices, and while maintaining the inside of the flask at 105 °C, they were simultaneously dropped over 2 hours. After the dropping was completed, the mixture was stirred at 105 °C for 3 hours to obtain a solution of the antifoaming agent (5).

[0179]

Chemical formula

[0180] As a result of measuring the molecular weight of the obtained antifoaming agent (5) by GPC, the weight average molecular weight (Mw) was 26,000.

[0181] (Synthesis Example 6: Synthesis of antifoaming agent (6)) Into a glass flask equipped with a stirring device, a thermometer, a cooling tube, and a dropping device, 60 parts by mass of propylene glycol methyl ether acetate was charged as a solvent, and the temperature was raised to 105 °C while stirring under a nitrogen stream. Next, 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 ethylene oxide chain repetitions is about 9) were dissolved in 100 parts by mass of propylene glycol methyl ether acetate to form a monomer solution. Separately, 5 parts by mass of t-butyl peroxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 20 parts by mass of propylene glycol methyl ether acetate to form a polymerization initiator solution. The two types of dropping liquids were each set in separate dropping devices, and while maintaining the inside of the flask at 105 °C, they were simultaneously dropped over 2 hours. After the dropping was completed, the solution of the defoaming agent (6) was obtained by stirring at 105 °C for 3 hours.

[0182] [Chemical formula]

[0183] As a result of measuring the molecular weight of the obtained defoaming agent (6) by GPC, the weight average molecular weight (Mw) was 10,000.

[0184] (Synthesis Example 7: Synthesis of defoaming agent (7)) 34 parts by mass of n-butyl acetate as a solvent was charged into a glass flask equipped with a stirrer, thermometer, condenser tube, and dropping device, and the temperature was raised to 95 °C while stirring under a nitrogen stream. Next, 16 parts by mass of a silicone monomer mixture represented by the following formulas (A7), (A8), and (A9), 15 parts by mass of methoxypolyethylene glycol methacrylate (the number of ethylene oxide chain repetitions is about 9), and 3 parts by mass of methyl methacrylate were dissolved in 33 parts by mass of n-butyl acetate to form a monomer solution. Separately, 3 parts by mass of t-butyl peroxy-2-ethylhexanoate as a radical polymerization initiator was dissolved in 10 parts by mass of n-butyl acetate to form a polymerization initiator solution. The two types of dropping liquids were each set in separate dropping devices, and while maintaining the inside of the flask at 95 °C, they were simultaneously dropped over 2 hours. After the dropping was completed, it was stirred at 95 °C for 2 hours, then the temperature was raised to 110 °C and further stirred for 1 hour to obtain a solution of the defoaming agent (7).

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

[0186] As a result of measuring the molecular weight of the obtained defoaming agent (7) by GPC, the average weight-average molecular weight (Mw) was 44,000.

[0187] (Synthesis Example 8: Synthesis of defoaming agent (8)) 30 parts by mass of propylene glycol methyl ether acetate as a solvent was charged into a glass flask equipped with a stirring device, a thermometer, a condenser tube, and a dropping device, and the temperature was raised to 105 °C while stirring under a nitrogen stream. Next, 5 parts by mass of a silicone dimethacrylate monomer (number-average molecular weight: 400) represented by the general formula (A1) and a silicone monomer mixture represented by the following formula (A10), 5 parts by mass of 3-(methacryloyloxy)propyltris(trimethylsiloxy)silane, and 10 parts by mass of methoxypolyethylene glycol methacrylate (the number of repeating units of the ethylene oxide chain is about 9) were dissolved in 10 parts by mass of propylene glycol methyl ether acetate to form a monomer solution. A polymerization initiator solution prepared by dissolving 1 part by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator in 7 parts by mass of propylene glycol methyl ether acetate was set in a separate dropping device, and while maintaining the inside of the flask at 105 °C, the two types of dropping solutions were simultaneously dropped over 2 hours. After completion of the dropping, the solution of defoaming agent (8) was obtained by stirring at 105 °C for 3 hours.

[0188] [Chemical formula]

[0189] As a result of measuring the molecular weight of the obtained defoaming agent (8) by GPC, the weight-average molecular weight (Mw) was 20,000.

[0190] (Synthesis Comparative Example 1: Synthesis of defoaming agent (1')) Into a glass flask equipped with a stirring device, a thermometer, a cooling tube, and a dropping device, 52 parts by mass of n-butyl acetate was charged 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 units of the ethylene oxide chain is about 9), and 3 parts by mass of t-butylperoxy-2-ethylhexanoate as a radical polymerization initiator dissolved in 15 parts by mass of n-butyl acetate were set in separate dropping devices as two types of dropping liquids. While maintaining the temperature inside the flask at 85 °C, the monomer solution and the polymerization initiator solution were simultaneously dropped over 2 hours. After the dropping was completed, 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 the defoaming agent (1').

[0191] As a result of measuring the molecular weight of the obtained defoaming agent (1') by GPC, the weight average molecular weight (Mw) was 40,000.

[0192] (Synthesis Comparative Example 2: Synthesis of defoaming agent (2')) A solution of the 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]

Chemical formula

[0194] As a result of measuring the molecular weight of the obtained defoaming agent (2') by GPC, the weight average molecular weight (Mw) was 25,000.

[0195] (Synthesis Comparative Example 3: Synthesis of defoaming agent (3')) A defoaming agent (3') solution was obtained in the same manner as in Synthetic 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] As a result of measuring the molecular weight of the obtained defoaming agent (3') by GPC, the weight average molecular weight (Mw) was 27,000.

[0197] A commercially available dimethyl silicone represented by the following (manufactured by Shin-Etsu Silicone Co., Ltd., "KF-96-50,000cs") was separately prepared as a defoaming agent (4').

[0198]

Chemical formula

[0199] Using the defoaming agent produced above, the following foaming test was conducted to evaluate the defoaming performance of the defoaming agent. The results are shown in Table 1.

[0200] (Preparation of Lubricating Oil Composition) To 100 parts by mass of a base lubricating oil mainly composed of a lubricating oil base oil (paraffin-based mineral oil) and containing a small amount of various additives (viscosity index improver, phosphite compound, thiadiazole compound, calcium-based detergent, metal deactivator, ashless dispersant, antioxidant, etc.), the defoaming agent shown in Table 1 diluted with kerosene was added in the amount shown in Table 1 to obtain a lubricating oil composition. In Comparative Example 5, no defoaming agent was added.

[0201] The following foaming test was carried out on the obtained lubricating oil composition. The results are shown in Table 1. (Foaming Test) The foaming test was carried out in accordance with the homogenizer method disclosed in JP-A-2008-120880. 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 according to the following conditions. After the stirring was completed, the reading (mL) of the oil level before stirring was subtracted from the reading (mL) of the foaming surface 3 seconds after the stirring was completed, and the amount of foaming (mL) was obtained. The smaller the amount of foaming, the better the defoaming property. Rotation speed: 16,000 rpm Oil temperature: 80 °C or 120 °C Oil volume: 80 ml Container: 200 ml graduated cylinder (inner diameter φ36 mm) Stirring time: 1 minute

[0202]

Table 1

[0203] From the results in Table 1, it can be read that the defoamers (1) to (8), which are polymers containing a polymerizable monomer having a specific silicone functional group and two or more polymerizable unsaturated groups, all exhibit excellent defoaming properties even in a high-temperature environment. On the other hand, the defoamers (1') to (4'), which do not use a polymerizable monomer having a specific silicone functional group and two or more polymerizable unsaturated groups as a polymerization component, do not show 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; and 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, 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). 【Chemistry 1】 (In the above general formula (A-1) and the above general formula (A-2), R 11 is each independently an alkyl group having 1 to 6 carbon atoms; R 12 is independently an alkyl group having 1 to 6 carbon atoms; Each R 13 independently represents 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 a group represented by the formula -OSi(R 16 ) 3 (each R 16 independently represents an alkyl group having 1 to 6 carbon atoms); x indicates the number of repetitions, y is an integer of 1 or more, z1 and z2 each independently represent an integer of 1 or more; z3 is an integer of 2 or more, L 11 is an organic group having a valence of z1+1 which may have an ether bond; L 12 is an organic group having a valence of z2+1 which may have an ether bond; L 13 is an organic group having a valence of z3+y which may have an ether bond; L 14 is a divalent organic group which may have an ether bond.

2. A polymerizable monomer (A') having at least a polymerizable component, the polymerizable monomer (A1) having a polysiloxane structure represented by -[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 having two or more polymerizable unsaturated groups, and / or a polymerizable monomer (A2) having a functional group represented by -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, and each R' is independently an alkyl group having 1 to 6 carbon atoms), and having two or more polymerizable unsaturated groups, The defoaming agent contains a polymer, wherein the polymerizable monomer (A') is a compound represented by the following general formula (A-3): 【Chemistry 2】 (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, L １５ each independently represents a divalent organic group which may have an ether bond, a is a repeating unit and is an integer of 0 to 3.

3. A polymerizable monomer (A'') having at least a polymerizable component, the polymerizable monomer (a1) having a polysiloxane structure represented by -[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 having two or more polymerizable unsaturated groups, and / or a polymerizable monomer (a2) having a functional group represented by -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, and each R' is independently an alkyl group having 1 to 6 carbon atoms), and having two or more polymerizable unsaturated groups; The defoaming agent contains a polymer, wherein the polymerizable monomer (A″) is a compound represented by the following general formula (A-4): 【Chemistry 3】 (In the above general formula (A-4), R １３ each independently represents a hydrogen atom or a methyl group, R ５２ are each independently an alkyl group having 1 to 6 carbon atoms, L １６ are each independently a divalent organic group which may have an ether bond.

4. A polymerizable monomer (A''') having at least a polymerizable component, the polymerizable monomer (a1) having a polysiloxane structure represented by -[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 having two or more polymerizable unsaturated groups, and / or a polymerizable monomer (a2) having a functional group represented by -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, and each R' is independently an alkyl group having 1 to 6 carbon atoms), and having two or more polymerizable unsaturated groups; The defoaming agent contains a polymer, wherein the polymerizable monomer (A''') is a compound represented by the following general formula (A-5): 【Chemistry 4】 (In the above general formula (A-5), R １３ each independently represents 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, L １７ each independently represents a divalent organic group which may have an ether bond, each t is a repeating unit, each independently an integer from 1 to 100; u is a repeating unit and is an integer from 1 to 10.

5. A polymerizable monomer (A'''') having at least a polymerizable component, the polymerizable monomer (a1) having a polysiloxane structure represented by -[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 having two or more polymerizable unsaturated groups, and / or a polymerizable monomer (a2) having a functional group represented by -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, and each R' is independently an alkyl group having 1 to 6 carbon atoms), and having two or more polymerizable unsaturated groups; The defoaming agent contains a polymer, wherein the polymerizable monomer (A'''') is a compound represented by the following general formula (A-6): 【Chemistry 5】 (In the above general formula (A-6), R １３ each independently represents a hydrogen atom or a methyl group, R ５５ are each independently an alkyl group having 1 to 6 carbon atoms, L １８ each independently represents a divalent organic group which may have an ether bond, v is a repeating unit, each independently an integer from 1 to 100.

6. The defoaming agent according to claim 1, wherein the polymerizable monomer (A) in the polymerization components is in the range of 5 to 75 mass %.

7. The defoaming agent according to any one of claims 1 to 5, wherein the polymerization component further contains 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.

8. The defoaming agent according to claim 7, 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): 【Chemistry 6】 【Chemistry 7】 (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 an ether bond having 1 to 18 carbon atoms, 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 an ether bond having 1 to 18 carbon atoms, R ２９ is a hydrogen atom or a methyl group, R ３０ each independently represents 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, L １９ and L ２０ each independently represents a divalent organic group which may have an ether bond or a single bond, L ２１ and L ２２ each independently represents a divalent organic group which may have an ether bond or a single bond, L ２３ represents an organic group having a valence of r+1 which may have an ether bond or a single bond, L ２４ represents 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 which may have an ether bond, L ２６ represents a single bond or an organic group having a valence of r+1 which may have an ether bond, L ２７ represents a single bond or an organic group having a valence of r6+1 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.

9. The defoaming agent according to claim 8, wherein the polymerizable monomer (B) contains at least one of the compounds represented by the general formulas (B-2), (B-7) and (B-8).

10. The defoaming agent according to claim 7, wherein the content of the polymerizable monomer (B) in the polymerization components is in the range of 5 to 75 mass%.

11. The defoaming agent according to claim 1, wherein the polymerization components further contain a polymerizable monomer (C) having two or more polymerizable unsaturated groups other than the polymerizable monomer (A).

12. The defoaming agent according to claim 11, wherein the polymerizable monomer (C) is a compound represented by the following general formula (C-1): 【Chemistry 8】 (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.

13. The defoaming agent according to claim 11, wherein the content of the polymerizable monomer (C) in the polymerization components is in the range of 5 to 70 mass%.

14. The defoaming agent according to any one of claims 1 to 5, wherein the weight average molecular weight of the polymer is in the range of 2,000 to 200,000.

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

16. The defoaming agent according to claim 15, wherein the polymerizable monomer (D) is a compound represented by the following general formula (D-1): 【Chemistry 9】 (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, s indicates the number of repetitions.)

17. A lubricating oil composition comprising a lubricating base oil and the antifoaming agent according to any one of claims 1 to 5.

18. 18. The lubricating oil composition of claim 17, which is used to lubricate the driving parts of a machine having an internal combustion engine or an electric motor.

19. 20. The lubricating oil composition of claim 17, wherein the lubricating oil composition is used in a motor vehicle having an internal combustion engine or an electric motor to lubricate the driving parts of said motor vehicle.

20. A machine using the lubricating oil composition according to claim 17 in a driving part.

Images