Nippon Oil Company

Nippon Mitsubishi Oil Corporation

Nippon Zeon Company, Ltd.

Harima Chemicals, Incorporated

Jinichi Igarashi

Toshio Yoshida

Masakuni Hirata

Yoko Matsuyama

Kazuhiro Yagishita

Kiyoshi Inoue

Yutaka Shikatani

Masaru Ushio

Shizuo Kitahara

Hiroyuki Takashima

Mitsuo Okada

Mineo Kagaya

Osamu Kurosawa

Harumichi Watanabe

Yoshihide Ishikawa

Isao Kurihara

Takeo Koizumi

Michio Miyamoto

Shinsuke Hasegawa

Kouzou Kamiya

Mituaki Ishimaru

Isao Honjo

Yuji Ikemoto

Kouichi Oshima

Lubricating oil compositions

Engine oil compositions are provided containing (A) a lubricating base oil having a kinematic viscosity at 100&deg; C. of 3 to 6 mm /S, a viscosity index of 120 or more, and a total aromatic content of 5 percent by mass or less and (B) a polymethacrylate-based viscosity index improver, preferably having a weight average molecular weight of 180,000 or more, (A) and (B) being blended in such an amount that the composition has a kinematic viscosity at 100&deg; C. of 4.0 to 9.3 mm /s. The engine oil compositions may also contain a molybdenumdithiocarbamate, as well as one or more other engine oil additives. The engine oil compositions preferably have a high-temperature, high shear viscosity at 150&deg; C. of 2.4 to 2.7 mPa&middot;s, a NOACK evaporation loss of 16 percent by mass or less, and a CCS viscosity at &minus;25&deg; C. of 3500 mPa&middot;s or less.

Engine oil compositions

An engine oil composition characterized by containing a major amount of lubricating base oil and (a) 0.01 to 30% by weight of an overbasic oil-soluble metal salt prepared by use of an alkaline-earth metal borate, (b) 0.01 to 5% by weight of a molybdenum dithiocarbamate, and (c) 0.01 to 5% by weight of an antioxidant as essential components, on the basis of the total amount of the composition.

Engine oil composition

Lubricant compositions comprise a lubricant base oil, and (A) a mono substituted amide type bissuccinimide in an amount from 0.5 to 20 percent by mass, (B) zinc dithiophosphate in an amount from 0.05 to 0.3 percent by mass of phosphorus, and (C) a metal-based detergent in an amount form 0.5 to 4.0 percent by mass of sulfated ash, based on the total mass of the composition. Lubricant compositions preferably further comprises (D) a dispersant type viscosity index improver in an amount from 0.1 to 20 percent by mass, based on the total mass of the composition.

Lubricant compositions

A lubricating oil composition comprises (A) a base oil, (B) a 3-methyl-5-tert-butyl-4-hydroxyphenyl substituted fatty acid ester in an amount of 0.1-5 percent by mass and (C) an auxiliary component, said auxiliary component being one member of the group of (a) a nitrogen-containing compound in an amount of 0.001-1 percent by mass, (b) a sulfur and/or phosphorus-containing compound in an amount of 0.1-5.0 percent by mass or (c) a phenolic compound in an amount of 0.1-5.0 percent by mass. This composition features the combination with a base oil of these specified components whereby there is provided synergistic effect conducive to inhibition or prevention of both oxidation and sludge formation while in use under elevated temperature conditions over extended periods of time.

Lubricating oil composition

An oil-soluble polyester having a weight average molecular weight of 10,000 to 1 000,000, which is a polycondensate prepared by polycondensing the following ingredients (A), (B) and (C):

Oil-soluble polyester, additive for lubricating oil, and lubricating oil

The present invention provides a lubricating oil composition which comprises in combination with a base oil:

A lubricating oil composition which comprises one or more base oils of the group consisting of (A) a mineral oil having a kinematic viscosity of 5-200 m.sup.2 /s at 40.degree. C. and an aromatics content of less than 15 percent by weight, (B) an olefinic polymer of 2-16 carbon atoms or its hydride having a number-average molecular weight of 250-4,000, and (C) an alkylbenzene having 1-4 alkyl groups of 1-40 carbon atoms and a total carbon number of said alkyl groups in the range of 6-40, said base oil or oils being blended with a 3-methyl-5-tert-butyl-4-hydroxyphenyl-substituted fatty acid ester in an amount of 0.1-5.0 percent by weight based on total composition. The inventive lubricant composition having such a base oil in combination with the specified fatty acid ester provides a synergistic effect conducive to inhibition or prevention of both oxidation and sludge formation while in use under elevated temperature conditions over extended periods of time.

Oxidation-inhibitive lubricating oil composition

Lubricant base oils are made up essentially of 2-15% by weight of a total aromatics content, greater than 60% by weight of isoparaffins and monocyclic naphthenes in total, more than 30% by weight of alkylbenzenes in the total aromatics content and smaller than 4% by weight of tricyclic and tetracyclic aromatics in the total aromatics content. The base oil has great viscosity index, small pour point, high oxidative stability and heat stability and sufficient capability to dissolve sludge.

Lubricating oils

The present invention provides a lubricating composition for internal combustion engines comprising (A) a lubricating base oil in an amount of about 100 parts by weight, and (B) a molybdenum dithiocarbamate in a amount within the range of from about 0.1 to about 3.0 parts by weight, said lubricating base oil consisting substantially of a hydro-cracked lubricating base oil in an amount of more than 70% by weight (on the basis of the amount of the lubricating base oil) wherein the hydro-cracked lubricating base oil is manufactured by hydro-cracking petroleum fraction and has a kinematic viscosity in the range of from about 2 to about 10 cSt at 100.degree. C., said hydro-cracked lubricating base oil containing aromatic hydrocarbons in an amount within the range of from about 3 to about 15% by weight, sulfur in an amount of less than 50 ppm by weight, and nitrogen in an amount of less than 5 ppm by weight on the basis of the amount of the hydro-cracked lubricating base oil.

Lubricating composition for internal combustion engine

A process for preparing oil-soluble nitrogen-containing compounds which comprises subjecting nitrogen-containing telogens and alpha-olefin taxogens to radical telomerization reaction. The nitrogen-containing compounds are mixtures of telomers having an average molecular weight not less than 300 and a nitrogen content of from 0.1 to 10 wt %. The compound may be further reacted with boron-bearing compounds or boron compounds to obtain oil-soluble nitrogen and boron-containing compounds. These compounds are useful as additives for fuel oils and lubricating oils.

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Yokohama, Japan

Jinichi Igarashi