Low molecular weight polyalkyl acrylate polymers can be used as high viscosity base fluids. A corresponding method can be used for their preparation. Lubricant compositions may contain such low molecular weight polyalkyl acrylate polymers and the compositions may be used as automatic transmission fluids, manual transmission fluids, continuously variable transmission fluids, gear oil formulations, industrial gear oil formulations, axle fluid formulations, dual clutch transmission fluids, dedicated hybrid transmission fluids, or hydraulic oils.

A composition comprising water, a glycol, and a polyalkylene glycol which has a biodegradability of at least 60% as determined using OECD 301F wherein the composition has a kinematic viscosity of at least 25 mm.sup.2/sec at 40° C. is useful as a rheology modifier, particularly in subsea applications. In some instances, the composition comprises 10 to 65 weight % water, 20 to 60 weight % of a glycol selected from ethylene glycol, diethylene glycol, triethylene glycol and tetra ethylene glycol, 10 to 40 weight % of a polyalkylene glycol, and 0 to 10% of additives based on total weight of the composition wherein the polyalkylene glycol has a—molecular weight of no more than 4000 g/mol and is characterized in that it is an oxyethylene/oxypropylene block copolymer having a weight percent of oxyethylene of at least 20% based on total weight of the copolymer.

A composition comprising water, a glycol, and a polyalkylene glycol which has a biodegradability of at least 60% as determined using OECD 301F wherein the composition has a kinematic viscosity of at least 25 mm.sup.2/sec at 40° C. is useful as a rheology modifier, particularly in subsea applications. In some instances, the composition comprises 10 to 65 weight % water, 20 to 60 weight % of a glycol selected from ethylene glycol, diethylene glycol, triethylene glycol and tetra ethylene glycol, 10 to 40 weight % of a polyalkylene glycol, and 0 to 10% of additives based on total weight of the composition wherein the polyalkylene glycol has a—molecular weight of no more than 4000 g/mol and is characterized in that it is an oxyethylene/oxypropylene block copolymer having a weight percent of oxyethylene of at least 20% based on total weight of the copolymer.

A polymer comprising units having the structure (I): ##STR00001##
wherein x is 2 or 3, wherein L is (CH.sub.2).sub.y, where y is an integer from 1 to 10, or wherein L is CH(CH.sub.3)CH.sub.2S(CH.sub.2).sub.z, where z is an integer from 1 to 5; wherein [Q] is absent or is a polymerised moiety consisting of units having the structure (II): ##STR00002##
wherein R is a hydrocarbyl group, or a hydrocarbyl group containing one or more heteroatoms, wherein R may be linear, branched or cyclic, saturated or unsaturated, and wherein R has from 1 to 30 carbon atoms; wherein [Q] either consists of identical units of structure (II), or wherein [Q] consists of more than one different units of structure (II), differing in group R; and wherein X is a halogen or another chain terminating group. The polymers may find use as additives in lubricating compositions where they provide friction improvement and wear reduction.

The present invention aims to provide a viscosity index improver composition and a lubricating oil composition having a low HTHS viscosity at 100° C., an excellent shear stability, and an excellent low temperature viscosity. The present invention relates to, for example, a viscosity index improver composition (C), containing: a copolymer (A) containing a polyolefin-based monomer (a) represented by the following formula (1) as a constituent monomer; a copolymer (B) containing a (meth)acrylic acid alkyl ester (c) having a C12-C15 straight-chain or branched alkyl group and a (meth)acrylic acid alkyl ester (d) having a C16-C20 straight-chain or branched alkyl group as constituent monomers; and a base oil, wherein a weight average molecular weight ratio {(A)/(B)} of the copolymer (A) to the copolymer (B) is 2 to 55, and a weight ratio (A/B) of the copolymer (A) to the copolymer (B) constituting the viscosity index improver composition (C) is 5 to 100:

##STR00001##

A lubricating oil composition may be suitable for a refrigerator and have excellent thermal stability when used with a refrigerant using difluoromethane (R32), trifluoroiodomethane (CF.sub.3I), and at least one selected from saturated fluorinated hydrocarbon compounds (HFC) other than difluoromethane (R32). Such compositions may include: a base oil (A) with at least one selected from a polyoxyalkylene glycol, a polyvinyl ether, a copolymer of a poly(oxy)alkylene glycol or a monoether thereof and a polyvinyl ether, and a polyol ester; and an aliphatic epoxy compound (B), wherein the content of the aliphatic epoxy compound (B) is more than 2.0% by mass based on the total amount of the lubricating oil composition.

A lubricant composition that comprises a hydrocarbon base oil, a polar viscosity improver; and an esterified polyalkylene glycol: R.sup.1[O(R.sup.2O).sub.n(R.sup.3O).sub.m(C═O)R.sup.4].sub.p, wherein R.sup.1 is a linear alkyl having 1 to 18 carbon atoms, a branched alkyl having 4 to 18 carbon atoms or an aryl with 6 to 30 carbon atoms; R.sup.2O is an oxypropylene moiety derived from 1, 2-propylene oxide; R.sup.3O is an oxybutylene moiety derived from butylene oxide, wherein R.sup.2O and R.sup.3O are in a block or a random distribution; R.sup.4 is a linear alkyl with 1 to 18 carbon atoms, a branched alkyl with 4 to 18 carbon atoms or an aryl with 6 to 18 carbon atoms; n and m are each independently integers ranging from 0 to 20 wherein n+m is greater than 0, and p is an integer from 1 to 4. The lubricant composition may have a viscosity index of at least 150, a kinematic viscosity at 100° C. from 2 to 5 centistokes and a kinematic viscosity at −20° C. of at most 600 centistokes.

A lubricant composition that comprises a hydrocarbon base oil, a polar viscosity improver; and an esterified polyalkylene glycol: R.sup.1[O(R.sup.2O).sub.n(R.sup.3O).sub.m(C═O)R.sup.4].sub.p, wherein R.sup.1 is a linear alkyl having 1 to 18 carbon atoms, a branched alkyl having 4 to 18 carbon atoms or an aryl with 6 to 30 carbon atoms; R.sup.2O is an oxypropylene moiety derived from 1, 2-propylene oxide; R.sup.3O is an oxybutylene moiety derived from butylene oxide, wherein R.sup.2O and R.sup.3O are in a block or a random distribution; R.sup.4 is a linear alkyl with 1 to 18 carbon atoms, a branched alkyl with 4 to 18 carbon atoms or an aryl with 6 to 18 carbon atoms; n and m are each independently integers ranging from 0 to 20 wherein n+m is greater than 0, and p is an integer from 1 to 4. The lubricant composition may have a viscosity index of at least 150, a kinematic viscosity at 100° C. from 2 to 5 centistokes and a kinematic viscosity at −20° C. of at most 600 centistokes.

A polymer surfactant for improving engine oil emulsion properties of a lubricating composition mixed with water and/or fuel contamination, particularly at very cold temperatures, is described herein. In approaches, selected polymeric and functionalized compounds can impart both robust emulsion properties and simultaneously deliver good low temperature fluidity for lubricating compositions that may contain residual amounts of water and/or fuel contamination. Lubricating compositions including such surfactants demonstrate robust properties at temperatures down to about −30° C.

Disclosed is a lubricant composition including: at least one base oil; at least one polyalkylene glycol with at least 50% by weight of butylene oxide units and having a kinematic viscosity, measured at 100° C. according to standard ASTM D445 (2015), which is greater than or equal to 50 mm2/s, a kinematic viscosity, measured at 40° C. according to standard ASTM D445 (2015), which is greater than or equal to 1000 mm2/s and a Viscosity Index, measured according to standard ASTM D2270 (2012), which is greater than or equal to 180. Also disclosed is the use of such a composition for transmission or gear lubrication.