Defoaming agent and lubricating oil composition
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), X 1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y 1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z 1 is a linking group linking the repeating unit X 1 and the side chain Y 1 ; wherein in the general formula (3), X 2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y 2 is a C 1-30 hydrocarbyl side chain; and Z 2 is a linking group linking the repeating unit X 2 and the side chain Y 2 .
1. A defoaming agent comprising
a polymer,
the polymer comprising:
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), X 1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y 1 is 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 Z 1 is a linking group linking the repeating unit X 1 and the side chain Y 1 ;
wherein in the general formula (2), R 1 and R 2 are each independently an organic group having a carbon number of 1 to 18; and
wherein in the general formula (3), X 2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group; Y 2 is a C 1-30 hydrocarbyl side chain; and Z 2 is a linking group linking the repeating unit X 2 and the side chain Y 2 ;
the polymer further comprising a repeating unit represented by the following general formula (4):
wherein in the general formula (4), X 3 is a repeating unit obtainable by polymerization of a third ethylenic unsaturated group; Y 3 is a side chain comprising 3 or more fluorine atoms; and Z 3 is a linking group linking the repeating unit X 3 and the side chain Y 3 .
2. The defoaming agent according to claim 1 ,
wherein X 3 is a repeating unit obtainable by polymerization of a third (meth)acryloyl group.
3. A defoaming agent comprising
a polymer,
the polymer comprising:
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), X 1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y 1 is 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 Z 1 is a linking group linking the repeating unit X 1 and the side chain Y 1 ;
wherein in the general formula (2), R 1 and R 2 are each independently an organic group having a carbon number of 1 to 18; and
wherein in the general formula (3), X 1 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group; Y 2 is a C 1-30 hydrocarbyl side chain; and Z 2 is a linking group linking the repeating unit X 1 and the side chain V;
wherein
X 1 is a repeating unit obtainable by polymerization of a second (meth)acryloyl group; and
X 1 is a repeating unit obtainable by polymerization of a first (meth)acryloyl group.
4. The defoaming agent according to claim 1 ,
wherein the polymer comprises the repeating unit represented by the general formula (1) in an amount of no less than 10 mass % on the basis of the total mass of all repeating units in the polymer.
5. The defoaming agent according to claim 1 ,
wherein the polymer has a weight average molecular weight of 10,000 to 1,000,000.
6. A lubricating oil composition comprising:
(A) a lubricant base oil; and
(B) the defoaming agent as in claim 1 , in an amount of 1 to 100 mass ppm in terms of silicon on the basis of the total mass of the composition.
7. A method for lubricating an automobile engine, an automobile transmission, or an automobile transaxle unit, comprising:
supplying the lubricating oil composition according to claim 6 , to an automobile engine, an automobile transmission, or an automobile transaxle unit.
8. The defoaming agent according to claim 3 ,
wherein the polymer comprises the repeating unit represented by the general formula (1) in an amount of no less than 10 mass % on the basis of the total mass of all repeating units in the polymer.
9. The defoaming agent according to claim 3 ,
wherein the polymer has a weight average molecular weight of 10,000 to 1,000,000.
10. A lubricating oil composition comprising:
(A) a lubricant base oil; and
(B) the defoaming agent as in claim 3 , in an amount of 1 to 100 mass ppm in terms of silicon on the basis of the total mass of the composition.
11. A method for lubricating an automobile engine, an automobile transmission, or an automobile transaxle unit, comprising:
supplying the lubricating oil composition according to claim 10 to an automobile engine, an automobile transmission, or an automobile transaxle unit.