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.

An oleaginous corrosion-resistant lubricating composition comprising at least one poly-alpha olefin synthetic oil and effective amounts of metal salts of sulfonic acids, metal salts of carboxylic acids, metal salts of mixtures of said sulfonic and carboxylic acids, alkylated aromatic stabilizers as solubility modifiers, pour-point depressants, at least one antioxidant, triazole deactivator compounds and fluoroacrylate copolymers.

An oleaginous corrosion-resistant lubricating composition comprising at least one poly-alpha olefin synthetic oil and effective amounts of metal salts of sulfonic acids, metal salts of carboxylic acids, metal salts of mixtures of said sulfonic and carboxylic acids, alkylated aromatic stabilizers as solubility modifiers, pour-point depressants, at least one antioxidant, triazole deactivator compounds and fluoroacrylate copolymers.

The present invention relates to a viscosity index improver containing a copolymer (A) that contains, as essential constituent monomers, a fluorine atom-containing monomer (a) represented by the following formula (1) and a monomer (b) represented by the following formula (2),

wherein the copolymer (A) has a solubility parameter of 8.1 to 10.0 (cal/cm.sup.3).sup.1/2, and a mass ratio (b/a) of the monomer (b) to the monomer (a) in the monomers constituting the copolymer (A) is 0.01 to 42:

##STR00001##

wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 is a C2-C4 alkylene group; p is an integer of 0 or 1; q is an integer from 0 to 20, each R.sup.2 may be the same as or different from each other when q is 2 or greater; and Y is a monovalent group in which one or more or all of hydrogen atoms in a C1-C40 hydrocarbon group are replaced by fluorine atoms, and

##STR00002##

wherein R.sup.3 represents a hydrogen atom or a methyl group; X.sup.1 is a group represented by O or NH; R.sup.4 is a C2-C4 alkylene group; r is an integer of 0 or 1; s is an integer from 0 to 20, and each R.sup.4 may be the same as or different from each other when s is 2 or greater; and R.sup.5 is a C1-C40 hydrocarbon group.

The present invention relates to a viscosity index improver containing a copolymer (A) that contains, as essential constituent monomers, a fluorine atom-containing monomer (a) represented by the following formula (1) and a monomer (b) represented by the following formula (2),

wherein the copolymer (A) has a solubility parameter of 8.1 to 10.0 (cal/cm.sup.3).sup.1/2, and a mass ratio (b/a) of the monomer (b) to the monomer (a) in the monomers constituting the copolymer (A) is 0.01 to 42:

##STR00001##

wherein R.sup.1 represents a hydrogen atom or a methyl group; R.sup.2 is a C2-C4 alkylene group; p is an integer of 0 or 1; q is an integer from 0 to 20, each R.sup.2 may be the same as or different from each other when q is 2 or greater; and Y is a monovalent group in which one or more or all of hydrogen atoms in a C1-C40 hydrocarbon group are replaced by fluorine atoms, and

##STR00002##

wherein R.sup.3 represents a hydrogen atom or a methyl group; X.sup.1 is a group represented by O or NH; R.sup.4 is a C2-C4 alkylene group; r is an integer of 0 or 1; s is an integer from 0 to 20, and each R.sup.4 may be the same as or different from each other when s is 2 or greater; and R.sup.5 is a C1-C40 hydrocarbon group.

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.

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.

The disclosure provides a fluoropolyether compound represented by formula (1):
R.sup.1CH.sub.2R.sup.2CH.sub.2R.sup.3
wherein R.sup.1 is C.sub.1-C.sub.10 alkoxy; R.sup.2 is (CF.sub.2).sub.pO(CF.sub.2O).sub.x(CF.sub.2CF.sub.2O).sub.y(CF.sub.2CF.sub.2CF.sub.2O).sub.z(CF.sub.2CF.sub.2CF.sub.2CF.sub.2O).sub.w(CF.sub.2).sub.p; x and y are each a real number of 0 to 30; z is a real number of 0 to 30; w is a real number of 0 to 20; p is an integer of 1 to 3; R.sup.3 is OCH.sub.2CH(OH)CH.sub.2OH, OCH.sub.2CH(OH)CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH, O(CH.sub.2).sub.mOH, or OCH.sub.2(OH)CHCH.sub.2OC.sub.6H.sub.4R.sup.4; m is an integer of 2 to 8; and R.sup.4 is hydrogen, C.sub.1-C.sub.4 alkoxy, amino, or an amide residue; and also provides a lubricant having the compound and a magnetic disk.

A fluorine-containing ether monocarboxylic acid aminoalkyl ester represented by the general formula:
C.sub.nF.sub.2n+1O[CF(CF.sub.3)CF.sub.2O].sub.aCF(CF.sub.3)COO(CH.sub.2).sub.bNR.sup.1R.sup.2
(wherein R.sup.1 is a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group, or an aralkyl group, preferably an alkyl group having 1 to 6 carbon atoms or an aryl group; R.sup.2 is an alkyl group having 1 to 12 carbon atoms, an aryl group, or an aralkyl group, preferably an alkyl group having 1 to 6 carbon atoms or an aryl group; n is an integer of 1 to 3; a is an integer of 2 to 20, preferably an integer of 4 to 10; and b is an integer of 1 to 12, preferably an integer of 1 to 3). Such a fluorine-containing ether monocarboxylic acid ester having an amino group at the end of the ester group is produced by reacting a perfluoroether carboxylic acid fluoride compound C.sub.nF.sub.2n+1O[CF(CF.sub.3)CF.sub.2O].sub.aCF(CF.sub.3)COF and a hydroxyalkyl amine compound HO(CH.sub.2).sub.bNR.sup.1R.sup.2 in the presence of an alkali metal fluoride.

The present invention relates to the use of highly viscous (per)fluoropolyether polymers as damping fluids and to a method for counteract vibrations and/or shocks in a device using highly viscous (per)fluoropolyether polymers.