A composition comprising a heat transfer portion and a lubricating portion, wherein the lubricating portion comprises one or more compounds according to formula (I) of the present disclosure, wherein W is H; Y is independently selected from the group consisting of F, Cl, Br and I; Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.PCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, polyalkylene glycol and polyolester; n is an integer from 2 to 250; m is an integer from 0 to 3; and p is an integer from 0 to 9.

This invention provides for a composition particularly useful in a method comprising applying the composition to a surface to be lubricated, said composition comprising: at least one polymer (P) comprising a partially or fully fluorinated, straight or branched, polyoxyalkylene chain (R.sub.f) having two chain ends, wherein one or both chain end(s) bear(s) a hydroxy-, alkoxy- or acyl-oxy-terminated polyoxyalkylene chain free from fluorine atoms (R.sub.a), said chain comprising from 4 to 50 fluorine-free oxyalkylene units, said units being the same or different from one another and being selected from —CH.sub.2CH.sub.2O— and —CH.sub.2CH(O)O—, wherein J is independently straight or branched alkyl or aryl, preferably methyl, ethyl or phenyl and water.

The present invention relates to a magnetic recording medium in which a lubricant layer contains a compound A represented by general formula (1) and a compound B represented by general formula (2), satisfying (A/B)=0.2 to 3.0, and has an average thickness of 0.8 nm to 2 nm. R.sup.1—C.sub.6H.sub.4OCH.sub.2CH(OH)CH.sub.2OCH.sub.2—R.sup.2—CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH . . . (1) (R.sup.1 is an alkoxy group having 1 to 4 carbon atoms. R.sup.2 is —CF.sub.2O(CF.sub.2CF.sub.2O).sub.x(CF.sub.2O).sub.yCF.sub.2— (x, y=0 to 15), —CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.zCF.sub.2CF.sub.2— (z=1 to 15), —CF.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2CF.sub.2).sub.nCF.sub.2CF.sub.2CF.sub.2— (n=0 to 4). HOCH.sub.2CF.sub.2CF.sub.2O(CF.sub.2CF.sub.2CF.sub.2O).sub.mCF.sub.2CF.sub.2CH.sub.2OCH.sub.2CH(OH)CH.sub.2OH . . . (2) (m is an integer).

A composition comprising a heat transfer portion and a lubricating portion, wherein the lubricating portion comprises one or more compounds according to formula (I): wherein W is independently selected from the group consisting of H, F, Cl, Br and I; Y is independently selected from the group consisting of F, Cl, Br and I; Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.PCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, polyalkylene glycol and polyolester; n is an integer from 2 to 250; m is an integer from 0 to 3; and p is an integer from 0 to 9.

A fluorine-containing ether compound represented by R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4—R.sup.5 is provided. (R.sup.3 is a perfluoropolyether chain; R.sup.1 and R.sup.5 are each independently any one of an alkyl group that may have a substituent, an organic group having at least one double bond or at least one triple bond, and a hydrogen atom; and —R.sup.2—CH.sub.2—R.sup.3 is represented by Formula (2), and R.sup.3—CH.sub.2—R.sup.4— is represented by Formula (3))
-[A]-[B]—O—CH.sub.2—R.sup.3  (2)
R.sup.3—CH.sub.2—O—[C]-[D]-  (3)
([A] is represented by Formula (4), [B] is represented by Formula (5), [C] is represented by Formula (6), [D] is represented by Formula (7), and in the formula, a and b are integers of 0 to 2, c is an integer of 2 to 5, d and f are integers of 0 to 2, and e is an integer of 2 to 5, and at least one of b and d in the formula is 1 or more) ##STR00001##

The present invention relates to compounds according to formula (Ia) or formula (Ib);

##STR00001##

wherein each W is independently selected from the group consisting of H, F, Cl, Br, I and (CY.sub.2).sub.mCY.sub.3; each Y is independently selected from the group consisting of F, Cl, Br and I; each Z is independently selected from the group consisting of H, OH, (CW.sub.2).sub.pCW.sub.3, CY.sub.3, OCW.sub.3, O(CW.sub.2).sub.pCW.sub.3, OCW((CY.sub.2).sub.mCY.sub.3)CWCW.sub.2, (CW.sub.2).sub.pOH, polyalkylene glycol and polyolester; n is an integer from 2 to 49; m is an integer from 0 to 3; p is an integer from 0 to 9; the molecular weight average (M.sub.W) is ≤5500; and the polydispersity index is ≤1.45; compositions comprising these compounds and methods for their production.

The present invention provides a grease composition or a lubricating oil composition which is capable of effectively preventing hydrogen brittleness-caused peeling from occurring on a rolling surface of a rolling bearing, is excellent in durability in a high temperature and speed operation, and can be used for a long time. A grease-packed bearing (1) has an inner ring (2), an outer ring (3), and a plurality of rolling elements (4). A sealing member (6) for sealing a grease composition (7) is provided at openings (8a) and (8b) disposed at both axial ends of the inner ring (2) and the outer ring (3). The grease composition (7) includes a base grease composed of a base oil and a thickener and an additive added to the base grease. The additive contains at least one compound selected from among plant-derived polyphenolic compounds and compounds formed by decomposition thereof. The above-described compounds include tannin, gallic acid, ellagic acid, chlorogenic acid, caffeic acid, curcumin, quercetin, and quinic acid.

A lubricant including a plurality of segments including a divalent center segment and two sidechain segments, each including a perfluoroalkyl ether moieties is provided in which a dewetting thickness of the lubricant may be determined based in-part on a segment weight average molecular weight of the segments. A magnetic recording medium and a magnetic data storage system including the lubricant are also 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. In the formula (1), R.sup.1 is represented by the following formula (2), R.sup.2 is represented by the following formula (3), R.sup.3 is a perfluoropolyether chain, and R.sup.4 is an organic end group different from R.sup.1—R.sup.2— and contains two or three polar groups, wherein each polar group is bonded to a different carbon atom, and the carbon atoms to which the polar groups are bonded are bonded to one another via a linking group containing a carbon atom to which the polar group is not bonded. In the formula (2), R.sup.5 is an alkoxy group selected from the group consisting of a methoxy, an ethoxy and a propoxy group. In the formula (3), w is 2 or 3.

##STR00001##

Provided is a compound which has heat resistance and decomposition resistance and with which a monomolecular film having a reduced thickness can be obtained. A fluoropolyether compound in accordance with an aspect of the present invention is represented by R.sup.1—C.sub.6H.sub.4O—CH.sub.2CH(OH)CH.sub.2OCH.sub.2—R.sup.2—CH.sub.2—O—CH.sub.2CH(OH)CH.sub.2—OC.sub.6H.sub.4—R.sup.1 where R.sup.1 is a hydrogen atom, an alkoxy group having 1 to 4 carbon atoms, an amino group, or an amide group, R.sup.2 is —CF.sub.2O(CF.sub.2CF.sub.2O).sub.xCF.sub.2—, and x is a real number of 1 to 35.