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.

Provided is a fluorine-containing ether compound capable of forming a lubricant layer having excellent wear resistance even when the thickness is thin, and suitable as a material of a lubricant for a magnetic recording medium. The fluorine-containing ether compound is a compound represented by the following formula (1): R.sup.1R.sup.2CH.sub.2R.sup.3CH.sub.2R.sup.4R.sup.5; wherein R.sup.3 is a perfluoropolyether chain; R.sup.1 is a terminal group bonded to R.sup.2; R.sup.5 is a terminal group bonded to R.sup.4; R.sup.1 is an alkenyl group or an alkynyl group; R.sup.5 is a group containing a heterocyclic ring; R.sup.2 is represented by the following formula (2); R.sup.4 is represented by the following formula (3); and a in the formula (2) and b in the formula (3) are each independently an integer of 1 to 3.

##STR00001##

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): ##STR00001##
wherein in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y.sup.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.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (3), X.sup.2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y.sup.2 is a C.sub.1-30 hydrocarbyl side chain; and Z.sup.2 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.2.

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): ##STR00001##
wherein in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y.sup.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.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (3), X.sup.2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y.sup.2 is a C.sub.1-30 hydrocarbyl side chain; and Z.sup.2 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.2.

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1): ##STR00001##
where in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y.sup.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.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (2), R.sup.1 and R.sup.2 are each independently an organic group having a carbon number of 1 to 18.

A defoaming agent comprising: a polymer comprising a repeating unit represented by the following general formula (1): ##STR00001##
where in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of an ethylenic unsaturated group; Y.sup.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.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (2), R.sup.1 and R.sup.2 are each independently an organic group having a carbon number of 1 to 18.

A novel method of preparing metal assemblies for long term storage and instant readiness for use, utilizing a light oil mixture or grease mixture incorporating functionalized and molecularly neutral PFPE fluid and a fluorosolvent.

A lubricant adheres to a magnetic recording medium via at least one of chemisorption or bonding, and contains a perfluorinated polyether attached to or terminated with a functional group that is phosphonic acid, silanol or carboxylic acid, and may be:

R.sub.1R.sub.fR.sub.1 where R.sub.f is CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.n, CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.nCF.sub.2, CF.sub.2O[CF(CF.sub.3)CF.sub.2O].sub.nCF.sub.2, CF.sub.2O(CF.sub.2CF.sub.2O).sub.m(CF.sub.2O).sub.nCF.sub.2, CF.sub.2O(CF.sub.2CF.sub.2O).sub.nCF.sub.2, n, m is from 1 to 100 and R.sub.1 is the functional group. A lubricant is formed from a multiple ether segments according to formula:

Re.sup.1Rb.sup.1-Ri-Rc-Ri-Rb.sup.2Re.sup.2; where Rc includes perfluoroalkyl ether, Rb.sup.1 and Rb.sup.2 are, independently, a sidechain segment including a perfluoroalkyl ether, optional Ri independently is a divalent linking segment including a functional group including elements from periodic table Group 13-17, and of Re.sup.1 and Re.sup.2 are phosphonic acid, silanol or carboxylic acid. Lubricant synthesis includes reacting a perfluorinated polyether with a halogenated functional group, selected from phosphonic acid, silanol or carboxylic acid.

One aspect of the disclosure relates to a sliding member. The sliding member includes: a first sliding portion having a first lubricant placed between first parts of a first friction sliding mechanism; and a second sliding portion having a second lubricant placed between second parts of a second friction sliding mechanism. The first sliding portion has a lubricant feed port from which the first lubricant is fed, and the second sliding portion has no lubricant feed port from which the second lubricant is fed. The first lubricant contains base oil and an additive. The second lubricant contains base oil and an additive containing conductive carbon. The second lubricant contains a relatively larger amount of conductive carbon than the first lubricant.

One aspect of the disclosure relates to a sliding member. The sliding member includes: a first sliding portion having a first lubricant placed between first parts of a first friction sliding mechanism; and a second sliding portion having a second lubricant placed between second parts of a second friction sliding mechanism. The first sliding portion has a lubricant feed port from which the first lubricant is fed, and the second sliding portion has no lubricant feed port from which the second lubricant is fed. The first lubricant contains base oil and an additive. The second lubricant contains base oil and an additive containing conductive carbon. The second lubricant contains a relatively larger amount of conductive carbon than the first lubricant.