Grease composition contains (A) a straight-chain perfluoropolyether having a kinematic viscosity of 2-110 mm.sup.2/s at 40 C., (B) a branched perfluoropolyether having a kinematic viscosity of 2-100 mm.sup.2/s at 40 C., and (C) a fluorocarbon resin powder having a primary particle size of 1 m or less, wherein the contained amount of the fluorocarbon resin powder is 25-40 wt % with respect to the weight of the grease composition, and the weight ratio of the straight-chain perfluoropolyether (A) to the branched perfluoropolyether (B) is 15:85 to 70:30.

Hydrophilic coatings including a base coat layer and a top coat layer wherein at least one of the base coat and top coat compositions that form the hydrophilic coatings comprises a diacrylate compound have a number average molecular weight less than 1000.

Medical articles formed from a polyurethane-based resin including a modifying oligomer provide enhanced properties. A modifying oligomer incorporated into a backbone, as a side chain, or both of the polyurethane-based resin formed by a diisocyanate, a polyglycol, and a diol chain extender has at least one, preferably two, alcohol moieties (COH) and a functional moiety. Exemplary modifying oligomers are: a diol-containing perfluoropolyether incorporated into the backbone, a monofunctional polysiloxane (e.g., monodialcohol-terminated polydimethylsiloxane) incorporated as the side chain, and combinations thereof. Medical articles herein are self-lubricating and/or anti-fouling.

A fluorine-containing ether compound of the present invention is represented by the following General Formula (1). (In the General Formula (1), X is a trivalent atom or a trivalent atom group, A is a linking group including at least one polar group, B is a linking group having a perfluoropolyether chain, and D is a polar group or a substituent having a polar group at the end.)

[Chem. 1]

XA-B-D).sub.3 (1)

A fluorine-containing ether compound according to the present invention is a fluorine-containing ether compound represented by the following General Formula (1).

[Chem. 1]

(F.sub.2C.sub.IA-B-D).sub.2(1)

A fluorine-containing ether compound represented by Formula (1) is provided;

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

(In Formula (1), R.sup.1 and R.sup.5 may be the same as or different from each other and each represents an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 3 to 8 carbon atoms, R.sup.2 and R.sup.4 may be the same as or different from each other and each represents a divalent linking group having a polar group, and R.sup.3 represents a perfluoropolyether chain, with a proviso that R.sup.1 and R.sup.2 are, and R.sup.4 and R.sup.5 are divided due to the presence of an atom other than the carbon atom such as an oxygen atom).

Described herein are durable coatings, i.e. for medical devices, and methods of forming the coatings.

A sliding spline shaft device of the present invention includes a male spline and a female spline that is fitted to the male spline in an axially slidable manner, and at least one of the splines has a surface processed layer. The surface processed layer includes an undercoat layer, an intermediate layer containing phosphate, and a topcoat layer containing solid lubricant, in this order. The undercoat layer contains iron nitride and/or iron carbide. Thus, the surface of a base material has high hardness. As a result, microscopic deformation of the sliding surface is reduced, and increase in a real contact area is suppressed, whereby stick-slip is prevented.

Disclosed is a timepiece assembly including at least two elements in contact and mobile relative to each other, one of the elements having at least a first contact surface intended to rub against at least a second contact surface of the other element under dry lubrication conditions. At least one of the first and second contact surfaces is covered with a hydrophobic coating having an angle of contact with water greater than 90, preferably greater than 100 and preferably greater than 110, and a coefficient of friction lower than 0.15, preferably lower than 0.12 and preferably lower than 0.1, the variation in the coefficient of friction as a function of the relative humidity being lower than 25%, preferably lower than 10% and preferably lower than 5%.

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.1R.sup.2CH.sub.2R.sup.3CH.sub.2R.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.) ##STR00001##