Nok Kluber Co., Ltd.

Tatsuya Hashimoto

Akihiko Shimura

Toshio Nitta

Takeshi Hishinuma

Tetsuhiro Kitahara

Takao Kanno

A grease composition, which comprises a mixture of mutually incompatible thickener-containing non-fluorine-based base oil and thickener-containing fluorine-based base oil, the base oils being in a morphological structure, where one of the base oils is homogeneously dispersed in a particulate state in the other base oil, can be produced by kneading the mixture through a three-roll mill at least twice. By forming a morphological structure, one of the mutually incompatible non-fluorine-based base oil and fluorine-based base oil is homogeneously dispersed in a particulate state in the other base oil, that is, by forming a microscopically dispersed state, the following effects can be obtained: (1) less oil separation (smaller degree of oil separation) at elevated temperatures, (2) distinguished shearing stability, (3) low and stable friction coefficient, and (4) less abrasion.

Grease composition and process for producing the same

A lubricating grease composition, which comprises a base oil consisting of a mixture of 100 parts by weight of at least one of a perfluoropolyether oil (A), represented by RfO[CF(CF)CFO](CFCFO)Rf (where Rf is a perfluoroalkyl group having 1-5 carbon atoms, p+q=2-200, q/p=0-2, and q may be 0), and a perfluoropolyether oil (B), represented by F(CFCFCFO)CF(where s=2-100), and 0-100 parts by weight of at least one of a perfluoropolyether oil (C), represented by RfO(CFCFO)(CFO)Rf (where m+n=3-200 and m:n=10-90:90-10), and a perfluoropolyether oil (D), represented by RfO[CF(CF)CFO](CFCFO)(CFO)Rf (where a+b+c=3-200, b is 0 or an integer of 1 or more, and c is an integer of 1 or more), preferably further admixed with a thickening agent, can suppress corrosion of metallic materials by corrosive gases and also has a good heat resistance.

Lubricating grease composition

A lubricating oil composition, which comprises a perfluoropolyether base oil, and a fluorine-containing polyether diphosphonic acid ester, represented by the following general formula:(RO)(RO)P(O)(CH)CF(CF)[OCFCF(CF)]O(CF)O[CF(CF)CFO]CF(CF)(CH)P(O)(OR)(OR)(where R, R, R, and Rare hydrogen atoms, alkyl groups, cycloalkyl groups, aryl groups, alkylaryl groups, aralkyl groups, or any of the foregoing groups can be halogen atom-substituted groups, subscripts a, b, c, d, and e are in conditions of 2&#x2266;a+e&#x2266;8, b+d&#x2266;28, and 1&#x2266;c&#x2266;10, and b and d can be 0), and a grease composition which further contains a thickening agent in addition to the lubricating oil composition, have distinguished abrasion resistance and rust preventiveness without deteriorating the heat resistance inherent in the lubricating oil and the grease containing a perfluoropolyether oil as a base oil.

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Ibaraki, Japan

Tatsuya Hashimoto