Mitsui Chemicals, Inc.

Shuhei Yamamoto

Masahiro Yamashita

Takayuki Uekusa

Akio Hayakawa

Akihiro Udagawa

Toyoaki Sasaki

Kiyohide Inomata

Ikuko Ebisawa

Yusuke Saito

An object of the present invention is to provide a lubricating oil composition that is particularly excellent in viscosity characteristics at a low temperature of −35° C., i.e., the lubricating oil composition inhibiting an increase in low temperature viscosity while securing a viscosity necessary at an elevated temperature, and being excellent in storage stability in a low temperature environment. The present invention relates to a lubricating oil composition including a copolymer (A) and a base oil (B), in which the copolymer (A) satisfies the following requirement (a-1), and the content ratio between the copolymer (A) and the base oil (B) is such that the copolymer (A) is in a range of 0.1 to 50 parts by mass per 100 parts by mass in total of the copolymer (A) and the base oil (B). (a-1) The copolymer (A) is a copolymer of 4-methyl-1-pentene and an α-olefin having 20 or less carbon atoms excluding 4-methyl-1-pentene, including a constituent unit derived from 4-methyl-1-pentene within a range of 1 mol % or more and less than 30 mol % relative to the total constituent units.

Lubricating oil composition

A lubricating oil composition with a resin (A) and a base oil (B), the resin (A) is in a range of 0.01 to 50 parts by mass per 100 parts of (A) and (B), the resin (A) satisfies the following requirements: (A-1) the resin (A) is a polymer including a constituent unit from 4-methyl-1-pentene in a range of 60 to 99 mol % and a constituent unit from an α-olefin having 2 to 20 carbon atoms (excluding 4-methyl-1-pentene) in a range of 1 to 40 mol % (provided that 4-methyl-1-pentene and the α-olefin is 100 mol %); (A-2) intrinsic viscosity [η] measured in decalin at 135° C. is in a range of 0.01 to 5.0 dl/g; (A-3) a melting point (Tm) is in a range of 110 to 150° C. as determined by DSC; and the base oil (B) has (B-1) kinematic viscosity at 100° C. is in a range of 1 to 50 mm/s.

An object of the present invention is to provide a lubricating oil composition particularly excellent in viscosity characteristics at a low temperature. The present invention provides: a lubricating oil composition including a polymer (A) and a base oil (B), wherein the polymer (A) satisfies the following requirement (A-1), and the content ratio of the polymer (A) and the base oil (B) is such that the ratio of a resin (A) is within the range of from 0.1 to 50 parts by mass with respect to 100 parts by mass of the total amount of the polymer (A) and the base oil (B). (A-1) The polymer (A) is a polymer containing a structural unit derived from an &#x3b1;-olefin having 20 or less carbon atoms.

Lubricating oil composition, viscosity modifier for lubricating oil, and additive composition for lubricating oil

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Ichihara, Japan

Shuhei Yamamoto