Fluoropolyether compounds that can be used as a lubricant, such as for magnetic recording media. The compounds have a terminal group that includes a phenol or benzene. The fluoropolyether compounds reduce the head to media distance while keeping comparable reliability in a hard disk drive compared to current industrial widely used fluoropolyether based lubricants.

Fluoropolyether compounds that can be used as a lubricant, such as for magnetic recording media. The compounds have a terminal group that includes a phenol or benzene. The fluoropolyether compounds reduce the head to media distance while keeping comparable reliability in a hard disk drive compared to current industrial widely used fluoropolyether based lubricants.

An object of an aspect of the present invention is to provide: a lubricant excellent in adsorbability on the surface of a magnetic disk and in contamination resistance; and a magnetic disk which uses the lubricant and which is excellent in durability. The lubricant in accordance with an aspect of the present invention contains a fluoropolyether compound having, at a terminal thereof, a hydroxyalkenyl group or a hydroxyalkynyl group.

A product, according to one approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer. A polymeric binder binds the encapsulated nanoparticles. A product, according to another approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer, and a polymeric binder binding the encapsulated nanoparticles. An average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 20 nanometers. An average thickness of the recording layer is less than 0.2 microns.

A product, according to one approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer. A polymeric binder binds the encapsulated nanoparticles. A product, according to another approach, includes a recording layer. The recording layer includes encapsulated nanoparticles each comprising a magnetic nanoparticle encapsulated by an encapsulating layer, and a polymeric binder binding the encapsulated nanoparticles. An average diameter of the magnetic nanoparticles is in a range of 2 nanometers to 20 nanometers. An average thickness of the recording layer is less than 0.2 microns.

The invention provides a fullerene compound; a lubricant that is for a magnetic recording medium and that contains the fullerene compound; and a magnetic recording medium. The fullerene compound is an ionic liquid that is represented by general formula (1) and is formed from a Bronsted acid (H.sub.n1X) and a Bronsted base ([R.sub.2R.sub.3)N—].sub.m1—R.sub.1); wherein one of the Brønsted acid and the Broønsted base contains a group having a fullerene; and the other contains a perfluoroalkyl chain.

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Provided is a fluorine-containing ether compound that can be suitably used as a material for a lubricant for a magnetic recording medium, capable of forming a lubricant layer having excellent chemical substance resistance and wear resistance even when the thickness is small. A fluorine-containing ether compound represented by the following formula (1):

R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1)

In the formula (1), R.sup.3 is a perfluoropolyether chain. R.sup.2 and R.sup.4 are divalent linkage groups having a polar group, and may be the same or different. R.sup.1 and R.sup.5 are terminal groups bonded to R.sup.2 or R.sup.4, which may be the same or different, and at least one of R.sup.1 and R.sup.5 is an organic group having 1 to 8 carbon atoms wherein one or more hydrogen atoms of the organic group is substituted with a cyano group.

A fluorine-containing ether compound characterized by being represented by the following formula (1):

R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1)

In the formula (1), R.sup.3 is a perfluoropolyether chain. R.sup.2 and R.sup.4 are divalent linkage groups having a polar group and may be the same or different. R.sup.1 and R.sup.5 are bonded to an atom other than a carbon atom of R.sup.2 or R.sup.4. R.sup.1 and R.sup.5 are terminal groups composed of an organic group having 1 to 8 carbon atoms and may be the same or different. At least one of R.sup.1 and R.sup.5 is a chain organic group having 1 to 8 carbon atoms wherein one or more hydrogen atoms of the chain organic group is substituted with a group having an amide bond.

This fluorine-containing ether compound is represented by Formula (1).
R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5  (1) (in Formula (1), R.sup.1 is an aryl group or an aralkyl group, R.sup.2 is a divalent linking group having 0 or 1 polar group, R.sup.3 is a perfluoropolyether chain, R.sup.4 is a divalent linking group having 2 or 3 polar groups, and R.sup.5 is an aryl group or an aralkyl group.)

A fluorine-containing ether compound represented by the following formula (1).
C.sub.6H.sub.6-n—[O—R.sup.1—O—CH.sub.2—R.sup.2—CH.sub.2—R.sup.3].sub.n  (1)
(in the formula (1), n is an integer of 2 or 3, R.sup.1 is any one of —CH.sub.2CH.sub.2—, —CH.sub.2CH.sub.2CH.sub.2— and —CH.sub.2CH(OH)CH.sub.2—, R.sup.2 is a perfluoropolyether chain, R.sup.3 is —OCH.sub.2CH(OH)CH.sub.2O(CH.sub.2).sub.mOH (m in the formula is an integer of 2 to 4)).