A method of making a coating solution includes the steps of polymerising an initial monomer feed comprising an N-vinyl pyrrolidone and an acrylate, preferably methacrylate, salt in water to synthesise a copolymer thereof, acidifying the resulting copolymer-water mixture to give free carboxylic acid groups along the copolymer backbone, diluting the aqueous solution down with alcohol, and adding a cross-linking agent which is capable of reacting with the carboxylic acid groups and curing the copolymer at a later stage after the coating solution has been applied to a substrate and the copolymer coated thereon. Also disclosed are a coating solution in storage, a method of coating a substrate which is on, or is part of, a medical device or other article, a substrate, article or medical device having a coating so applied, and a coated medical device packaged in a hydration solution. The aqueous-alcoholic coating solution may be stored for an extended period, suitably for at least one month and desirably for substantially longer, without deteriorating.

An additive for a lubricating composition includes an ionic tetrahedral borate compound which includes a cation and a tetrahedral borate anion having a boron atom, the boron atom has at least one aliphatic bidentate di-oxo ligand. The cation may be selected to provide detergent and/or dispersant and/or antioxidant properties to a lubricating composition.

The invention relates to a chain guide, respectively a chain tensioner for use in a lubricated sliding system, comprising a surface layer or bearing or comprising a sliding element comprising a surface layer, the surface layer being mainly made of a polymeric material containing a matrix polymer and optionally other components dispersed in said matrix polymer, wherein the matrix polymer consists of a semi-crystalline polyamide (SCPA) having a tensile modulus at 140° C. of at least 800 MPa (measured by the method according to ISO 527-1A). The invention also relates to a power train drive system comprising an engine, a transmission differential and a drive shaft system, a drive chain and a plastic component comprising a sliding element in contact with the lubricated drive chain, wherein the chain guide, the chain tensioner, respectively the sliding element has a coefficient of friction (CoF), measured in lubrication oil at 140° C. at a nominal contact pressure of 1 MPa and a speed of 1 m/s, of at most 0.07.

A lubricating grease composition containing a base oil having a kinematic viscosity of 10 mm.sup.2/s or more and 60 mm.sup.2/s or less at 40° C.; a thickener containing at least one soap selected from a metal soap and a metal complex soap; and a solid lubricant containing porous polyamide particles. An amount of the porous polyamide particles blended is 1% by mass or more and 20% by mass or less based on a total mass of the lubricating grease composition.

A well bore cementing system may comprise a spacer fluid and a cement slurry. The spacer fluid may be positioned within a well bore, and the spacer fluid may comprise a first surfactant package comprising one or more surfactants. The cement slurry may be positioned within the well bore, and the cement slurry may comprise a second surfactant package comprising one or more surfactants.

The present invention relates to a composition suitable to be used as working fluid, said composition being in the form of a solution and comprising at least one (per)fluoropolyether polymer [polymer (P)] and at least one amorphous polymer [polymer (F)].

Selected comb polymers include specified amounts of macromonomer and imide functionalization. Further, a method is useful for the preparation of such comb polymers. Lubricant compositions including such comb polymers are useful for reducing wear and fuel consumption of lubricant compositions, especially of engine oil (EO) compositions.

Drilling fluid compositions include a base fluid, at least one additive chosen from an emulsifier, weighting material, fluid-loss additive, viscosifier, or alkali compound, and from 0.1 wt. % to 1 wt. %, based on total weight of the drilling fluid composition, of an ethoxylated alcohol compound having the formula R—(OCH.sub.2CH.sub.2).sub.7—OH, in which R is a saturated or unsaturated, linear or branched hydrocarbyl group having from 8 to 20 carbon atoms. The base fluid may be an aqueous base fluid. Methods for drilling a subterranean well include operating a drill in a wellbore in the presence of a drilling fluid composition including the base fluid, the additive, and the ethoxylated alcohol compound.

In one embodiment, a spacer fluid may comprise a base fluid and a surfactant package. The surfactant package may comprise one or more surfactants, where the surfactant package comprises a first surfactant having the chemical structure R—(OC.sub.2H.sub.4).sub.x—OH. R may be a hydrocarbyl group having from 9 to 20 carbon atoms, and x may be an integer from 5 and 15. The first surfactant may have a hydrophilic-lipophilic balance (HLB) of from 12 to 13.5.

Embodiments are directed to a lubricant package for water based drilling fluids. The lubricant package includes water, a polyethylene glycol, and a lubricating agent. The lubricating agent includes triethanolamine, or a C.sub.12-C.sub.14 alcohol ethoxylate, or a combination of triethanolamine and C.sub.12-C.sub.14 alcohol ethoxylate. The weight ratio of the polyethylene glycol to the lubricating agent in the lubricant package is from 1:2 to 2:1. Embodiments are also directed to a water-based drilling fluid composition including an aqueous base fluid, one or more additives, and the lubricant package for water based drilling fluids.