Jxtg Nippon Oil & Energy Corporation

Jx Nippon Oil Energy Corporation

Shingo Matsuki

Akira Takagi

Go Tatsumi

Masaaki Itou

Isao Kurihara

Hironori Isoh

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), Xis a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Yis a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Zis a linking group linking the repeating unit Xand the side chain Y; wherein in the general formula (3), Xis a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Yis a Chydrocarbyl side chain; and Zis a linking group linking the repeating unit Xand the side chain Y.

Defoaming agent and lubricating oil composition

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1): where in the general formula (1), Xis a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Yis a side chain comprising a linear or branched polysiloxane structure, the polysiloxane structure comprising a repeating unit represented by the following general formula (2) and having a polymerization degree of 5 to 300; and Zis a linking group linking the repeating unit Xand the side chain Y; wherein in the general formula (2), Rand Rare each independently an organic group having a carbon number of 1 to 18.

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&#xb0; 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.

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Tokyo, Japan

Shingo Matsuki