The present invention relates to a novel process for the synthesis of (per)fluoropolyether polymers, to certain novel (per)fluoropolyether polymers. The present invention also relates to the use of the (per)fluoropolyether polymers thus obtained as intermediate compounds for the manufacture of further polymers suitable for use as lubricants, notably for magnetic recording media (MRM).

A deposition composition includes a solvent comprising a hydrofluorothioether compound represented by the following general formula (I): Rf—S—Rh where Rf is a fluorinated or perfluorinated group having 2-9 carbon atoms and optionally includes one or more catenated heteroatoms or chlorine atoms, and Rh is a non-fluorinated hydrocarbon group having 1-3 carbon atoms. The deposition composition further includes a coating material that is soluble or dispersible in said solvent.

A fluorine-containing ether compound represented by the formula (1) is provided. The fluorine-containing ether compound is represented by the following formula (1). R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4 (1) (R.sup.3 is a perfluoropolyether chain; R.sup.1 is the formula (2), a in the formula (2) is an integer of 2 or 3, R.sup.5 and R.sup.6 are the same or different substituents. R.sup.5 and R.sup.6 may form a ring structure together with a nitrogen atom; R.sup.2 is the formula (3), b in the formula (3) is an integer of 1 to 3; R.sup.4 is a terminal group having two or three polar groups, in which individual polar groups bond to different carbon atoms and the carbon atoms to which the polar groups bond are bonded to each other through a linking group having a carbon atom to which the polar groups do not bond.)

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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.

An object is to provide a magnetic recording medium having excellent traveling stability and a thin total thickness. The present technology provides a tape-shaped magnetic recording medium including: a magnetic layer; an underlayer; a base layer; and a back layer, in which a surface on a side of the magnetic layer has a kurtosis of 3.0 or more, a surface on a side of the back layer has a kurtosis of 2.0 or more, the surface on the magnetic layer side has arithmetic average roughness R.sub.a of 2.5 nm or less, the base layer includes a polyester as a main component, the magnetic recording medium has an average thickness t.sub.T of 5.6 μm or less, the magnetic recording medium includes a lubricant, the lubricant includes a fatty acid and a fatty acid ester, and a mass ratio between the fatty acid and the fatty acid ester extracted with hexane satisfies fatty acid/fatty acid ester≤0.6, and the magnetic recording medium has pores, and the pores have an average diameter of 6 nm or more and 11 nm or less when the diameters of the pores are measured in a state where the lubricant has been removed from the magnetic recording medium and the magnetic recording medium has been dried.

The present invention provides 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—R.sup.4—R.sup.5

(in the formula, R.sup.3 represents a perfluoropolyether chain; R.sup.1 and R.sup.5 each independently represent any of an alkyl group which may have a substituent, an organic group having a double bond or a triple bond, and a hydrogen atom; —R.sup.2—CH.sub.2—R.sup.3 is represented by -[A]-[B]—O—CH.sub.2—R.sup.3; R.sup.3—CH.sub.2—R.sup.4— is represented by R.sup.3—CH.sub.2—O—[C]-[D]-; [A] is represented by Formula (4), [B] is represented by Formula (5), [C] is represented by Formula (6), and [D] is represented by Formula (7)):

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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.

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 and may be the same or different from each other; 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 may be the same or different from each other; and at least one of R.sup.1 and R.sup.5 is an organic group having 1 to 8 carbon atoms and at least one of hydrogens included in the organic group is substituted by a cyano group).