POLYALKYLENE GLYCOL-BASED LUBRICANT COMPOSITION

Abstract

Disclosed is a lubricant composition including: an oil chosen from polyalkyl glycols (PAG or polyalkylene glycols); and an anti-wear additive chosen from compounds of formula (I)

##STR00001## in which R1 and R2, which may be identical or different, independently represent a linear or branched secondary alkyl group including from 2 to 7 carbon atoms, preferably from 3 to carbon atoms. This lubricant composition is particularly useful for the lubrication of a vehicle engine, preferably of a motor vehicle.

Claims

1-14. (canceled)

15. Composition comprising 1 to 99.5% by weight of an oil selected from polyalkyl glycols (PAG or polyalkylene glycols) and an anti-wear additive selected from the compounds of formula (I) ##STR00012## in which R1 and R2, which may be identical or different, independently represent a linear or branched secondary alkyl group comprising from 2 to 7 carbon atoms.

16. Composition according to claim 15 wherein the PAG is a block polymer of formula (II) or a random polymer of formula (II) ##STR00013## in which: R3 represents a linear or branched C.sub.1-C.sub.30-alkyl group; n represents a number ranging from 2 to 60; R4 and R5, identical or different, independently represent a hydrogen atom or a C.sub.1-C.sub.2-alkyl group.

17. Composition according claim 15 for which the PAG is chosen from a block polymer of formula (IIA) or a random polymer of formula (IIA) ##STR00014## in which: R3 represents a linear or branched C.sub.1-C.sub.30-alkyl group; m represents a number ranging from 2 to 60; R6 and R7 represent a hydrogen atom; or R6 represents a hydrogen atom and R7 represents a methyl group; or R6 represents a methyl group and R7 represents a hydrogen atom; or R6 and R7 represent a methyl group; or R6 represents an ethyl group and R7 represents a hydrogen atom; or R6 represents a hydrogen atom and R7 represents an ethyl group; a block polymer of formula (IIB) or a random polymer of formula (IIB) ##STR00015## in which: R3 represents a linear or branched C.sub.1-C.sub.30-alkyl group; p and q independently represent a number ranging from 1 to 30; R8 and R9 represent a hydrogen atom; or R8 represents a hydrogen atom and R9 represents a methyl group; or R8 represents a methyl group and R9 represents a hydrogen atom; or R8 and R9 represent a methyl group; or R8 represents an ethyl group and R9 represents a hydrogen atom; or R8 represents a hydrogen atom and R9 represents an ethyl group; R10 and R11 represent a hydrogen atom; or R10 represents a hydrogen atom and R11 represents a methyl group; or R10 represents a methyl group and R11 represents a hydrogen atom; or R10 and R11 represent a methyl group; or R10 represents an ethyl group and R11 represents a hydrogen atom; or R10 represents a hydrogen atom and R11 represents an ethyl group.

18. Composition according to claim 15 for which the PAG is chosen from a block polymer of formula (III) or a random polymer of formula (III) ##STR00016## in which: R3 represents a linear or branched C.sub.4-C.sub.12-alkyl group; p represents a number ranging from 1 to 30; q represents a number ranging from 1 to 30, or a block polymer of formula (IV) or a random polymer of formula (IV) ##STR00017## in which: R3 represents a linear or branched C.sub.8-C.sub.12-alkyl group; p represents a number ranging from 2 to 6; q represents a number ranging from 2 to 5. a block polymer of formula (V) or a random polymer of formula (V) ##STR00018## in which: R3 represents a linear or branched C.sub.4-C.sub.12-alkyl group; r represents a number ranging from 2 to 60.

19. Composition according to claim 15 wherein the PAG is a block polymer of formula (VI) or a random polymer of formula (VI) ##STR00019## in which: R12 represents a linear or branched C.sub.1-C.sub.30-alkyl group; s and t independently represent an average number ranging from 1 to 5.

20. Composition according to claim 15 comprising 1 to 99.5% by weight of PAG.

21. Composition according to claim 15 comprising from 1 to 30% by weight of PAG.

22. Composition according to claim 15 comprising from 40 to 99.5% by weight of PAG.

23. Composition according to claim 15 comprising from 5 to 80% by weight of PAG.

24. Composition according to claim 15 wherein the anti-wear additive is selected from compounds of formula (I) ##STR00020## in which R1 and R2, identical or different, represent a secondary C3-alkyl group or a secondary C6-alkyl group.

25. Composition according to claim 15 comprising from 0.1 to 3% by weight of compound of formula (I).

26. Composition according to claim 15 comprising a lubricating base oil.

27. Composition according to claim 15, further comprising an organic friction modifier selected from esters.

28. Method of lubricating a motor vehicle, preferably a motor vehicle, comprising at least one step of bringing the motor into contact with the lubricating composition according to claim 15.

Description

[0139] The present invention will now be illustrated using non-limiting examples.

EXAMPLE 1: LUBRICATING COMPOSITIONS ACCORDING TO THE INVENTION

[0140] Lubricating compositions according to the invention are prepared according to Table 1 below (the compositions are given by weight (g)).

[0141] In the compositions below: [0142] PAG 1: PAG comprising propylene oxide and butylene oxide units and an OH termination (corresponding to formula (IV) with p2.8 and q2.2) [0143] PAG 2: PAG comprising propylene oxide and butylene oxide units and a OCH.sub.3 termination (corresponding to formula (VI) with s3.5 and t2.8) [0144] Anti-wear 1 (Lubrizol 1371 marketed by LUBRIZOL): mixture of compound of formula (I) in which R1 and R2 represent a dimethyl butyl group, and of compound of formula (I) in which R1 and R2 represent an isopropyl group [0145] Anti-wear 2 (R03045 marketed by RheinChemie): mixture of compound of formula (I) in which R1 and R2 represent a pentyl group, and of compound of formula (I) in which R1 and R2 represent a butyl group [0146] Anti-wear 3 (KT2203 marketed by Kangtai Lubricant Additives): compound of formula (I) in which R1 and R2 represent a primary C-8 alkyl group [0147] Friction modifier 1: glycerol mono-oleate [0148] Friction modifier 2 (Sakuralube 525 marketed by the company Adeka): molybdenum dithiocarbamate

TABLE-US-00002 TABLE 1 Com- Com- Composition 1 parative 1 parative 2 2 3 4 PAG 1 99.5 99.5 99.3 98.5 PAG 2 98.5 99 Anti-wear 1 0.5 0.5 0.5 0.5 Anti-wear 2 0.5 Anti-wear 3 0.7 Friction modifier 1 1 1 Friction modifier 2 0.5

EXAMPLE 2: EVALUATION OF ANTI-WEAR PROPERTIES

[0149] This evaluation is based on a procedure based on the ASTM D2670 standard requiring the use of a FALEX tribometer and whose test conditions are described below. [0150] test pieces: FALEX steel [0151] break-in time: 300 s [0152] test duration: 180 min [0153] break-in load: 445 N [0154] test load: 1335 N [0155] speed: 290 rpm [0156] ambient temperature

[0157] The results are presented in Table 2 and are expressed in m; the lower the value obtained, the better the anti-wear properties of the evaluated composition

TABLE-US-00003 TABLE 2 Composition 1 Comparative 1 Comparative 2 2 3 4 Total wear (m) 63 102 136 26 5 11

[0158] The results show that the lubricating compositions according to the invention (compositions 1, 2, 3 and 4) have improved anti-wear properties compared to comparative lubricating compositions (comparative compositions 1 and 2).