Abstract: Examples of the ester oil include diester oils such as dibutyl sebacate, dioctyl sebacate, di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl phthalate, and methyl acetyl ricinolate; aromatic ester oils such as trioctyl trimellitate, tridecyl trimellitate, and tetraoctyl pyromellitate; polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate; carbonate oil; complex ester oil which is an oligoester of polyhydric alcohol and mixed fatty acid including dibasic acid and monobasic acid; etc.

Abstract: A grease composition including: a base oil; a thickener; a zinc sulfonate; a polysulfide; an overbased calcium sulfonate; and triphenyl phosphite, in which a proportion of the zinc sulfonate with respect to a total mass of the base oil and the thickener is 0.030 mass% to 0.045 mass% in terms of a zinc content, a proportion of the polysulfide with respect to the total mass of the base oil and the thickener is 0.16 mass% to 0.24 mass% in terms of a sulfur content, a proportion of the overbased calcium sulfonate with respect to the total mass of the base oil and the thickener is 0.010 mass% to 0.015 mass% in terms of a calcium content, and a proportion of the triphenyl phosphite with respect to the total mass of the base oil and the thickener is 0.24 mass% to 0.36 mass%.

Abstract: A lubricating oil composition including: a lubricating base oil; (A) a first defoaming agent, the first defoaming agent being (A1) a first polymer, or (A2) a second polymer, or any combination thereof; and (B) a second defoaming agent, the second defoaming agent being a silicone defoaming agent, the (A1) first polymer including: a first polymer chain including a polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 2000 and being represented by the following general formula (1); and a second polymer chain bonded with the first polymer chain, the second polymer chain including a repeating unit represented by the following general formula (2), the (A2) second polymer being a copolymer of a first monomer component and a second monomer component, the first monomer component represented by the general formula (7) or (8), the second monomer component represented by the general formula (9).

Abstract: A grease composition including: an ester base oil; and a thickener, in which the thickener contains diurea expressed by the following formula (1): R1-NHCONH-C6H4-CH2-C6H4-NHCONH-R2 (1), in which R1 and R2 each independently represents one of: (A) an alicyclic group A expressed by R3-C6H10- (R3 represents hydrogen, a 2-methyl group, a 3-methyl group, or a 4-methyl group); (B) an alkyl group B expressed by n-CmH2m+1 (m represents an integer of 6 to 10); and (C) an alkyl group C expressed by n-CmH2m+1 (m represents an integer of 16 to 20), and in which the diurea is arranged so that the alicyclic group A is 5 to 35 mol %, a total of the alicyclic group A and the alkyl group B is 55 to 95 mol %, and the remainder is the alkyl group C, based on a total of R1 and R2.

Abstract: A lubricating oil composition including: a lubricating base oil; (A) a first defoaming agent, the first defoaming agent being (A1) a first polymer, or (A2) a second polymer, or any combination thereof; and (B) a second defoaming agent, the second defoaming agent being a silicone defoaming agent, the (A1) first polymer including: a first polymer chain including a polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 2000 and being represented by the following general formula (1); and a second polymer chain bonded with the first polymer chain, the second polymer chain including a repeating unit represented by the following general formula (2), the (A2) second polymer being a copolymer of a first monomer component and a second monomer component, the first monomer component represented by the general formula (7) or (8), the second monomer component represented by the general formula (9).

Abstract: A defoaming agent including a polymer, the polymer including: at least one first polymer chain including a polysiloxane structure represented by the following general formula (1); and at least one second polymer chain including a repeating unit represented by the following general formula (2) and bonded to the first polymer chain: wherein in the formula (1), repeating units may be in any order; each of R1 and R2 is independently a C1-18 organic group comprising no fluorine atom; at least one of R3 and R4 is the organic group comprising no less than 3 fluorine atoms; m is an integer of no less than 1; and n+m is 5 to 2000, wherein in the formula (2), X1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y1 is a substituted or unsubstituted C1-40 hydrocarbyl group; and Z1 is a linking group linking X1 and Y1.

Abstract: A defoaming agent obtainable by a process, the process including the step of: (i) polymerizing (B) at least one defoaming agent monomer in (A) a polymerization solvent under coexistence of (C) a polymer soluble in the polymerization solvent.

Abstract: A lubricating oil composition including: a lubricant base oil; (A) a first defoaming agent obtainable by a process, the process including the step of: polymerizing (b) at least one defoaming agent monomer in (a) a polymerization solvent under coexistence of (c) a polymer soluble in the polymerization solvent; and (B) a second defoaming agent being a silicone defoaming agent.

Abstract: A defoaming agent including a polymer, the polymer including a repeating unit represented by the following general formula (1); and a repeating unit represented by the following general formula (3): wherein in the general formula (1), X1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z1 is a linking group linking the repeating unit X1 and the side chain Y1; wherein in the general formula (3), X2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y2 is a C1-30 hydrocarbyl side chain; and Z2 is a linking group linking the repeating unit X2 and the side chain Y2.

Abstract: A defoaming agent including a polymer, the polymer including: at least one first polymer chain including a polysiloxane structure represented by the following general formula (1); and at least one second polymer chain including a repeating unit represented by the following general formula (2) and bonded to the first polymer chain: wherein in the formula (1), repeating units may be in any order; each of R1 and R2 is independently a C1-18 organic group comprising no fluorine atom; at least one of R3 and R4 is the organic group comprising no less than 3 fluorine atoms; m is an integer of no less than 1; and n+m is 5 to 2000, wherein in the formula (2), X1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y1 is a substituted or unsubstituted hydrocarbyl group; and Z1 is a linking group linking X1 and Y1.

Abstract: A defoaming agent obtainable by a process, the process including the step of: (i) polymerizing (B) at least one defoaming agent monomer in (A) a polymerization solvent under coexistence of (C) a polymer soluble in the polymerization solvent.

Abstract: A lubricating oil composition containing a lubricating base oil and on the basis of the total mass of the composition, (A) a boron-containing ashless dispersant in an amount of 100 to 500 ppm by mass as boron, (B) a phosphorous additive in an amount of 300 to 800 ppm by mass as phosphorus, (C) an amide- and/or imide-based friction modifier in an amount of 1 to 4 percent by mass, and (D) an alkali metal- and/or alkaline earth metal-based detergent in an amount of 100 to 300 ppm by mass as metal, and having a 40° C. kinematic viscosity of 30 mm2/s or lower is provided. The lubricating oil composition, which has a low viscosity to improve fuel efficiency, also has superior anti-wear, anti-seizure, and anti-shattering properties, even when the composition is degraded by oxidation or by the elution of compounds from sealing materials after long term use.

Abstract: A lubricating oil composition including: a lubricant base oil; (A) a first defoaming agent obtainable by a process, the process including the step of: polymerizing (b) at least one defoaming agent monomer in (a) a polymerization solvent under coexistence of (c) a polymer soluble in the polymerization solvent; and (B) a second defoaming agent being a silicone defoaming agent.

Abstract: A defoaming agent including a polymer, the polymer including a repeating unit represented by the following general formula (1); and a repeating unit represented by the following general formula (3): wherein in the general formula (1), X1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z1 is a linking group linking the repeating unit X1 and the side chain Y1; wherein in the general formula (3), X2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y2 is a C1-30 hydrocarbyl side chain; and Z2 is a linking group linking the repeating unit X2 and the side chain Y2.

Abstract: A lubricating oil composition containing a lubricating base oil and on the basis of the total mass of the composition, (A) a boron-containing ashless dispersant in an amount of 100 to 500 ppm by mass as boron, (B) a phosphorous additive in an amount of 300 to 800 ppm by mass as phosphorus, (C) an amide- and/or imide-based friction modifier in an amount of 1 to 4 percent by mass, and (D) an alkali metal- and/or alkaline earth metal-based detergent in an amount of 100 to 300 ppm by mass as metal, and having a 40° C. kinematic viscosity of 30 mm2/s or lower is provided. The lubricating oil composition, which has a low viscosity to improve fuel efficiency, also has superior anti-wear, anti-seizure, and anti-shattering properties, even when the composition is degraded by oxidation or by the elution of compounds from sealing materials after long term use.