Polyalkylene glycol-based lubricant composition

Abstract

A lubricant composition includes: an oil selected from among polyalkylene glycols (PAG); and a nitrogen compound selected from among amine phosphates or amine tungstates. The lubricant composition is particularly suitable for lubricating a vehicle engine, preferably a motor vehicle engine. Also disclosed is an engine lubrication method utilizing such composition.

Claims

1. Lubricating composition comprising from 1 to 30 wt % of an oil selected from polyalkyl glycols (PAG or polyalkylene glycols), a nitrogen compound selected from amine tungstates and further comprising a friction modifier selected from organomolybdenum compounds, and derivatives thereof.

2. Lubricating composition according to claim 1 for which the nitrogen compound is chosen from: amine tungstates obtained from at least one fatty amine comprising at least one linear alkyl group comprising from 8 to 15 carbon atoms; amine tungstates obtained from at least one fatty amine comprising at least one branched alkyl group comprising from 8 to 15 carbon atoms; a mixture of at least one amine tungstate obtained from at least one fatty amine comprising at least one linear alkyl group comprising from 8 to 15 carbon atoms, and an amine tungstate obtained from at least one fatty amine comprising at least one branched alkyl group comprising from 8 to 15 carbon atoms.

3. Lubricating composition according to claim 1, wherein the PAG is a block polymer of formula (II) or a random polymer of formula (II) ##STR00018## 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.

4. Lubricating composition according to claim 1 for which the PAG is chosen from a block polymer of formula (IIA) or a random polymer of formula (IIA) ##STR00019## 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) ##STR00020## 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.

5. Lubricating composition according to claim 1 for which the PAG is chosen from a block polymer of formula (III) or a random polymer of formula (III) ##STR00021## 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) ##STR00022## 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) ##STR00023## 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.

6. Lubricating composition according to claim 1, wherein the PAG is a block polymer of formula (VI) or a random polymer of formula (VI) ##STR00024## 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.

7. Lubricating composition according to claim 1, comprising from 1 to 20% by weight of PAG.

8. Lubricating composition according to claim 1, comprising from 1 to 15% by weight of PAG.

9. Lubricating composition according to claim 1, comprising from 0.1 to 3% by weight of nitrogen compound.

10. Lubricating composition according to claim 1, comprising a lubricating base oil.

11. Method for the lubrication of an engine or for the lubrication of an automobile engine comprising at least one step of bringing the motor into contact with the lubricating composition according to claim 1.

Description

EXAMPLE 1: LUBRICATING COMPOSITIONS ACCORDING TO THE INVENTION

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

(2) In the compositions below: PAG 1: PAG comprising propylene oxide and butylene oxide units and an OH termination (corresponding to formula (IV) with p≈2.8 and q≈2.2) PAG 2: PAG comprising propylene oxide and butylene oxide units and a —OCH.sub.3 termination (corresponding to formula (VI) with s≈3.5 and t≈2.8) PAG 3 (Synalox 50-15B® marketed by the company DOW CHEMICAL): PAG based on ethylene oxide units and propylene oxide units PAG 4 (Synalox 100-20B® marketed by DOW CHEMICAL): PAG based on propylene oxide units PAG 5: PAG comprising propylene oxide and butylene oxide units and an —OH termination (corresponding to formula (IV) with p≈5 and q≈4) nitrogen compound 1 (Irgalube 349® marketed by the company BASF): mixture of compound of formula (IA) and of compound of formula (IB) in which R1 represents a hexyl or ethylhexyl group, while R2 represents an alkyl group comprising from 11 to 14 carbon atoms. nitrogen compound 2 (Vanlube W-324® marketed by the company Vanderbilt): mixture of at least one amine tungstate obtained from at least one fatty amine comprising at least one linear alkyl group comprising from 11 to 14 carbon atoms and an amine tungstate obtained from at least one fatty amine comprising at least one branched alkyl group comprising from 11 to 14 carbon atoms friction modifier (Sakuralube 525® marketed by the company Adeka): molybdenum dithiocarbamate base oil (Yubase 4+® marketed by the company SK): Group III base oil (kinematic viscosity of 4.1 mm.sup.2/s measured at 100° C. according to the ASTM D445 standard) polymer 1 (Viscoplex 6-565® marketed by the company Evonik): polymethacrylate polymer 2 (SV203® marketed by Infineum): hydrogenated polyisoprene/styrene additive package: succinimide dispersant, zinc dithiophosphate anti-wear, calcium salicylate detergent, phenolic antioxidant, diphenylamine antioxidant

(3) TABLE-US-00002 TABLE 1 Composition 1 2 3 4 5 6 7 8 PAG 1 98.9 99.5 98.4 PAG 2 98.9 98.4 PAG 3 98.4 PAG 4 98.4 PAG 5 8 Nitrogen 1.1 1.1 1.1 1.1 1.1 1.1 1.1 compound 1 Nitrogen 0.5 compound 2 Friction 0.5 0.5 0.5 0.5 modifier Base oil 74.4 Polymer 1 2.8 Polymer 2 2.9 Package of 10.9 additives

EXAMPLE 2: EVALUATION OF ANTI-WEAR PROPERTIES

(4) 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. test pieces: FALEX steel break-in time: 300 s test duration: 180 min break-in load: 445 N test load: 1335 N speed: 290 rpm ambient temperature

(5) The results are presented in Table 2 and are expressed in μm; the lower the value obtained, the better the anti-wear properties of the evaluated composition

(6) TABLE-US-00003 TABLE 2 Composition 1 2 3 4 5 6 7 8 Total wear (μm) 28 24 24 38 24 18 44 28

(7) The results show that the lubricating compositions according to the invention (compositions 1 to 8) have good anti-wear properties.

(8) It should be noted that the improvement of the anti-wear properties is actually obtained: in the presence or absence of additional base oils, in the presence or absence of additional additives.