The object of the present invention is to provide a foreign substance removing lubricant composition having high foreign substance removing effects and being capable of improving the lubricating properties as compared to conventional lubricant compositions, a foreign substance removing lubricant composition applied member, and a method for using the foreign substance removing lubricant composition. The foreign substance removing lubricant composition of the present invention comprises a perfluoroalkyl group containing compound (S) having a perfluoroalkyl group or a fluoropolyether containing compound. As a result, foreign substance removing effects can be enhanced, and the lubricating properties can be improved as compared to the conventional lubricant compositions.

A polymer [polymer (P)] comprising a plurality of (per)fluoropolyether (PFPE) segments [segments (S.sup.RF)] joined together by hydrogenated (poly)ether segments [segments (S.sup.H)], said polymers (P) having two end groups [groups (E)], each group (E) comprising a hydroxy or a leaving group, with the proviso that the hydrogenated (poly)ether segment (S.sup.H) is not a segment of formula CH.sub.2OCH.sub.2 OCH.sub.2 is herein disclosed. Disclosed is also a method for the manufacture of polymer (P) and a polymer obtainable by full or partial fluorination of polymer (P). Polymer (P) and polymers obtainable therefrom by full or partial fluorination can be conveniently used in the manufacture of lubricant compositions or of compositions for imparting hydro-/oleo-repellence to substrates. Said polymers can also be used as intermediates for the manufacture of other polymers or block copolymers.

Provided is a lubricant for magnetic recording medium, where the lubricant includes an ionic liquid including an anionic component and a cationic component, wherein the anionic component includes a fluorine-containing chain having a number average molecular weight of 1,500 or less, the cationic component is a cation of cyclic amidine, and the cation of the cyclic amidine includes a fluorine-containing chain that is either a perfluoroalkyl chain or a perfluoropolyether chain.

A lubricating oil friction modifier and a preparation method therefor and use thereof are provided. The lubricating oil friction modifier has a chemical formula of A.sub.xB.sup.y+(C.sup.?).sub.y. In the formula, A is a perfluoropolyether acyl group, B.sup.y+ represents a cationic group having x amino groups and y ammonium ions, C.sup.? is BF.sub.4.sup.?, PF.sub.6.sup.?, AsF.sub.6.sup.?, FAP.sup.?, TFSI.sup.?, Mn.sub.2O.sub.4 or ClO.sub.4.sup.?, x is an integer greater than or equal to 1, y is an integer greater than or equal to 1, and x+y?2. The lubricating oil friction modifier has a good solubility with fluorine oil and fluorine grease, will not precipitate in the fluorine oil and the fluorine grease after being added, and can significantly improve the wear resistance of a lubricating oil such as the fluorine oil and the fluorine grease.

A method is provided that forms a solid film on a bearing component of a rolling bearing. A solution containing a fluorine compound and a lubricant having no functional group is allowed to adhere to the bearing component as a liquid film, the fluorine compound containing 3-(trimethoxysilyl) propyl methacrylate, hexafluoropropene, and methyl methacrylate as components. The solid film is formed on the at least one of the bearing components by hardening the adhering liquid film.

A copolymer of polyalkylphenyl siloxane and alkylfluoroalkyl siloxane obtainable by reacting a dispersion of ingredient (i) an alkylfluoroalkyl siloxane and ingredient (ii) one or more polyalkylphenyl siloxane(s) in the presence of ingredient (iii) a basic catalyst at a temperature of between 40 C. to 300 C.

This disclosure relates to a process for extracting a perfluoropolyether. The process involves: (a) contacting a solvent comprising a liquid or supercritical carbon dioxide with a lubricating grease comprising a thickener and the perfluoropolyether in an extraction zone to form an extraction solution comprising an extracted perfluoropolyether; and (b) recovering the extracted perfluoropolyether from the extraction solution; wherein the recovered extracted perfluoropolyether comprises no more than about 2 wt % of the thickener.

This disclosure relates to a process for extracting a perfluoropolyether. The process involves: (a) contacting a solvent comprising a liquid or supercritical carbon dioxide with a lubricating grease comprising a thickener, an extraction aid material, and the perfluoropolyether in an extraction zone to form an extraction solution comprising an extracted perfluoropolyether; and (b) recovering the extracted perfluoropolyether from the extraction solution; wherein the recovered extracted perfluoropolyether comprises no more than about 2 wt % of the thickener.

A threaded joint (1) for pipes disclosed herein includes a pin (5) and a box (8). The pin (5) and the box (8) each include a contact surface including a threaded portion (4, 7) and a metal contact portion. The threaded joint (1) for pipes includes a solid lubricant coating (21) on at least one of the contact surfaces of the pin (5) and the box (8), the solid lubricant coating (21) including a binder, a lubricant additive, an anti-rust additive, and a plasticizer.

Provided are a magnetic disk and, in particular, a compound which makes it possible to realize a lubricant having excellent heat resistance and solubility in a fluorine-based solvent. A perfluoropolyether compound in accordance with an aspect of the present invention has, in hydrocarbon groups at both terminals thereof, five or six hydroxyl groups in total.