Provided are a fluoropolyether compound having high heat resistance and capable of maintaining a surface protection layer even under high temperature, and a lubricant and a magnetic disk that contain the fluoropolyether compound. The fluoropolyether compound includes: three groups whose main chain contains a perfluoropolyether chain; and a trivalent linking group represented by Formula (1) below, the three groups being bound together via the trivalent linking group:

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where R.sub.1 is a saturated hydrocarbon group having 1 to 3 carbon atoms, a perfluoroalkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, a hydroxyl group, or an amino group, and A.sub.1, A.sub.2, and A.sub.3 are each independently an aromatic group.

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.)

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.)

This fluorine-containing ether compound is represented by formula (1) shown below.

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

In formula (1), R.sup.2 is a perfluoropolyether chain represented by a formula (2) shown below. R.sup.1 is a terminal group that is bonded to R.sup.2 via a CH.sub.2 group, and is represented by a formula (3) shown below. R.sup.3 is bonded to R.sup.2 via a CH.sub.2 group, is a terminal group having at least one hydroxyl group, and may be the same as, or different from, R.sup.1.

—(CF.sub.2).sub.p-1—O—((CF.sub.2).sub.pO).sub.q—(CF.sub.2).sub.p-1—  (2)

In formula (2), p represents an integer of 2 to 3, and q indicates the average polymerization degree and is a number within a range from 1 to 20.

—O(CH.sub.2—CH(OH)—CH.sub.2—O).sub.2—CH.sub.2—(CH.sub.2).sub.n,—OH  (3)

In formula (3), n represents an integer of 1 to 8.

This fluorine-containing ether compound is represented by formula (1) shown below.

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

In formula (1), R.sup.2 is a perfluoropolyether chain represented by a formula (2) shown below. R.sup.1 is a terminal group that is bonded to R.sup.2 via a CH.sub.2 group, and is represented by a formula (3) shown below. R.sup.3 is bonded to R.sup.2 via a CH.sub.2 group, is a terminal group having at least one hydroxyl group, and may be the same as, or different from, R.sup.1.

—(CF.sub.2).sub.p-1—O—((CF.sub.2).sub.pO).sub.q—(CF.sub.2).sub.p-1—  (2)

In formula (2), p represents an integer of 2 to 3, and q indicates the average polymerization degree and is a number within a range from 1 to 20.

—O(CH.sub.2—CH(OH)—CH.sub.2—O).sub.2—CH.sub.2—(CH.sub.2).sub.n,—OH  (3)

In formula (3), n represents an integer of 1 to 8.

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 present invention relates to a composition for lubricating a propulsion system of an electric or hybrid vehicle, comprising at least one base oil and at least one fire retardant corresponding to formula (I)
R.sub.F-L-R.sub.H  (I) in which R.sub.F is a perfluorinated or partially fluorinated group, R.sub.H is a hydrocarbon-based group, and L is a linker. The invention also relates to the use of at least one fire retardant of formula (I), in a composition for lubricating a propulsion system of an electric or hybrid vehicle, including at least one battery, to give it ignition-resistance properties. Finally, the invention relates to a process for cooling and fire-protecting a battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery, in particular a lithium-ion or nickel-cadmium battery, in contact with a composition according to the invention.

There is provided a fluorine-containing ether compound represented by the following formula. R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—OCH.sub.2CH(OH)CH.sub.2O—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5 (in the formula. R.sup.3 represents a perfluoropolyether chain; R.sup.2 and R.sup.4 represent a divalent linking group having a polar group; R.sup.1 and R.sup.5 represent a terminal group bonded to an oxygen atom of R.sup.2 or R.sup.4; and at least one of R.sup.1 and R.sup.5 is any one selected from the group consisting of an alkenyl group having 2 to 8 carbon atoms, an alkynyl group having 3 to 8 carbon atoms, an aromatic hydrocarbon-containing group, and an aromatic heterocycle-containing group).

High temperature lubricants for magnetic media are provided. One such lubricant includes fluoroalkyl, fluoroalkenyl, perfluoroalkyl, or perfluoroalkyl ether segments, anchoring functional groups engageable with a protective overcoat of a magnetic recording media, and cyclic functional groups. The lubricants can be used in conjunction with a magnetic recording medium and/or a magnetic data storage system.

Low-profile thermally stable lubricants for data storage devices are provided based on multi-dentate molecular designs. One such lubricant comprises perfluoroalkyl ether segments, a divalent linking segment, and anchoring functional groups attachable to, or engageable with, a protective overcoat of a magnetic recording medium. The lubricants can be used in conjunction with a magnetic recording medium and/or a magnetic data storage system.