Use of alkoxylated polyethylene glycols in lubricating oil compositions

Abstract

The presently claimed invention is directed to the use of polyethylene glycols that are prepared by alkoxylating polyethylene glycol with at least one C.sub.8-C.sub.30 epoxy alkane in lubricating oil compositions.

Claims

1. A lubricant which comprises an alkoxylated polyethylene glycol of general formula (II) ##STR00019## wherein m is an integer in the range of 1 to 30, m is an integer in the range of 1 to 30, (m+m) is an integer in the range of 3 to 50, n is 0, n is 0, p is an integer in the range of 0 to 90, p is an integer in the range of 0 to 90, k is an integer in the range of 3 to 30, R.sub.1 denotes an unsubstituted, linear alkyl radical having 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms, R.sub.2 denotes CH.sub.2CH.sub.3, and R.sub.3 denotes CH.sub.3, and wherein the ratio of (m+m) to k is in the range of 1:1 to 3:1 and the ratio of (p+p) to k is in the range of 0.8:1 to 4:1, and whereby the concatenations denoted by k are distributed to form a block polymeric structure and the concatenations denoted by p, p, n, n, m and m are distributed to form a block polymeric structure or a random polymeric structure.

2. A method of reducing friction in a lubricating oil composition comprising utilizing the lubricating oil composition comprising at least one lubricant wherein the lubricant comprises an alkoxylated polyethylene glycol of general formula (II) ##STR00020## wherein m is an integer in the range of 1 to 50, m is an integer in the range of 1 to 50, (m+m) is an integer in the range of 2 to 90, n is an integer in the range of 0 to 75, n is an integer in the range of 0 to 75, p is an integer in the range of 0 to 90, p is an integer in the range of 0 to 90, k is an integer in the range of 2 to 50, R.sub.1 denotes an unsubstituted, linear or branched, alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 or 28 carbon atoms, R.sub.2 denotes CH.sub.2CH.sub.3, and R.sub.3 denotes CH.sub.3, and whereby the concatenations denoted by k are distributed to form a block polymeric structure and the concatenations denoted by p, p, n, n, m and m are distributed to form a block polymeric structure or a random polymeric structure.

3. A lubricant which comprises an alkoxylated polyethylene glycol of general formula (II) ##STR00021## wherein m is an integer in the range of 1 to 30, m is an integer in the range of 1 to 30, (m+m) is an integer in the range of 3 to 50, n is an integer in the range of 3 to 40, n is an integer in the range of 3 to 40, (n+n) is an integer in the range of 6 to 40, p is an integer in the range of 0 to 75, p is an integer in the range of 0 to 75, (p+p) is an integer in the range of 0 to 90, k is an integer in the range of 3 to 40, R.sub.1 denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms, R.sub.2 denotes CH.sub.2CH.sub.3, and R.sub.3 denotes CH.sub.3, and whereby the concatenations denoted by k are distributed to form a block polymeric structure and the concatenations denoted by p, p, n, n, m and m are distributed to form a block polymeric structure or a random polymeric structure.

4. A lubricant which comprises an alkoxylated polyethylene glycol of general formula (II) ##STR00022## wherein m is an integer in the range of 1 to 25, m is an integer in the range of 1 to 25, (m+m) is an integer in the range of 3 to 50, n is 0, n is 0, p is an integer in the range of 3 to 45, p is an integer in the range of 3 to 45, (p+p) is an integer in the range of 6 to 80, k is an integer in the range of 3 to 30, R.sub.1 denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms, R.sub.2 denotes CH.sub.2CH.sub.3, and R.sub.3 denotes CH.sub.3 and whereby the concatenations denoted by k are distributed to form a block polymeric structure and the concatenations denoted by p, p, n, n, m and m are distributed to form a block polymeric structure or a random polymeric structure.

5. The lubricant according to claim 1, wherein the alkoxylated polyethylene glycol has a weight average molecular weight Mw in the range of 500 to 20,000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

6. The lubricant according to claim 3, wherein n is an integer in the range of 3 to 25, n is an integer in the range of 3 to 25, (n+n) is an integer in the range of 6 to 35, p is 0, p is 0, k is an integer in the range of 3 to 30, and R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10, 11, 12, 13, 14, 15, 16, 17 or 18 carbon atoms.

7. The lubricant according to claim 6, wherein the ratio of (m+m) to k is in the range of 1:1 to 3:1 and the ratio of (n+n) to k is in the range of 1:1 to 6:1.

8. A lubricating oil composition comprising at least one lubricant as claimed in claim 1.

9. A method of enhancing the friction modification properties of a lubricating oil composition in the lubrication of a mechanical device comprising formulating said lubricating oil composition as claimed in claim 8 and lubricating the mechanical device.

10. The lubricant according to claim 3, wherein n is an integer in the range of 3 to 20, n is an integer in the range of 3 to 20, (n+n) is an integer in the range of 6 to 30, and R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms.

11. The lubricant according to claim 3, wherein n is an integer in the range of 3 to 20, n is an integer in the range of 3 to 20, (n+n) is an integer in the range of 6 to 30, and wherein the ratio of (m+m) to k is in the range of 1:1 to 3:1 and the ratio of (n+n) to k is in the range of 1:1 to 6:1.

12. The lubricant according to claim 3, wherein n is an integer in the range of 3 to 20, n is an integer in the range of 3 to 20, (n+n) is an integer in the range of 6 to 30, k is an integer in the range of 3 to 30, R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms, and wherein the ratio of (m+m) to k is in the range of 1:1 to 3:1 and the ratio of (n+n) to k is in the range of 1:1 to 6:1.

13. The lubricant according to claim 3, wherein m is an integer in the range of 1 to 25, m is an integer in the range of 1 to 25, (m+m) is an integer in the range of 3 to 40, n is an integer in the range of 6 to 15, n is an integer in the range of 6 to 15, (n+n) is an integer in the range of 12 to 25, p is an integer in the range of 0 to 25, p is an integer in the range of 0 to 25, (p+p) is an integer in the range of 0 to 70, k is an integer in the range of 3 to 30, R.sub.1 denotes an unsubstituted, linear alkyl radical having 8, 9, 10, 11 or 12 carbon atoms, wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (n+n) to k is in the range of 1:1 to 6:1.

14. The lubricant according to claim 4, wherein m is an integer in the range of 2 to 25, m is an integer in the range of 2 to 25, (m+m) is an integer in the range of 4 to 40, p is an integer in the range of 4 to 40, p is an integer in the range of 4 to 40, (p+p) is an integer in the range of 8 to 70, and R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms.

15. The lubricant according to claim 4, wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (p+p) to k is in the range of 0.8:1 to 4:1.

16. The lubricant according to claim 4, wherein p is an integer in the range of 3 to 40, p is an integer in the range of 3 to 40, (p+p) is an integer in the range of 6 to 70, R.sub.1 denotes an unsubstituted, linear alkyl radical having 8, 9, 10, 11 or 12 carbon atoms, and wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (p+p) to k is in the range of 0.8:1 to 4:1.

17. The lubricant according to claim 4, wherein p is an integer in the range of 3 to 40, p is an integer in the range of 3 to 40, (p+p) is an integer in the range of 6 to 70, R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms, wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (p+p) to k is in the range of 0.8:1 to 4:1.

18. The lubricant according to claim 4, wherein m is an integer in the range of 2 to 25, m is an integer in the range of 2 to 25, (m+m) is an integer in the range of 4 to 40, p is an integer in the range of 4 to 40, p is an integer in the range of 4 to 40, (p+p) is an integer in the range of 8 to 70, R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms, and wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (p+p) to k is in the range of 0.8:1 to 4:1.

19. The lubricant according to claim 3, wherein wherein m is an integer in the range of 2 to 25, m is an integer in the range of 2 to 25, (m+m) is an integer in the range of 4 to 40, n is an integer in the range of 3 to 20, n is an integer in the range of 3 to 20, (n+n) is an integer in the range of 6 to 30, p is 0, p is 0, k is an integer in the range of 3 to 30, R.sub.1 denotes an unsubstituted, linear alkyl radical having 9, 10 or 11 carbon atoms, and wherein the ratio of (m+m) to k is in the range of 1:1 to 2:1 and the ratio of (n+n) to k is in the range of 2:1 to 6:1.

20. The lubricant according to claim 3, wherein the alkoxylated polyethylene glycol has a weight average molecular weight Mw in the range of 500 to 20,000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

21. The lubricant according to claim 4, wherein the alkoxylated polyethylene glycol has a weight average molecular weight Mw in the range of 500 to 20,000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

22. The lubricant according to claim 19, wherein the alkoxylated polyethylene glycol has a weight average molecular weight Mw in the range of 500 to 20,000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

23. A lubricating oil composition comprising at least one lubricant as claimed in claim 3.

24. A lubricating oil composition comprising at least one lubricant as claimed in claim 4.

25. A lubricating oil composition comprising at least one lubricant as claimed in claim 19.

26. A method of reducing friction in a lubricating oil composition comprising utilizing the lubricating oil composition according to claim 1.

27. A method of reducing friction in a lubricating oil composition comprising utilizing the lubricating oil composition according to claim 3.

28. A method of reducing friction in a lubricating oil composition comprising utilizing the lubricating oil composition according to claim 4.

Description

EXAMPLES

(1) OHZ=hydroxyl number, determined according to DIN 53240

(2) Mn=number average molecular weight, determined according to DIN 55672-1 and referred to Polystyrene calibration standard.

(3) Mw=weight average molecular weight, determined according to DIN 55672-1 and referred to Polystyrene calibration standard.

(4) PD=polydispersity, determined according to DIN 55672-1

(5) Measuring Physical Properties

(6) The kinematic viscosity was measured according to the standard international method ASTM D 445.

(7) The viscosity index was measured according to the ASTM D 2270.

(8) The pour point according was measured to DIN ISO 3016.

(9) Friction Coefficient Evaluation

(10) The fluids were tested in the MTM (Mini-Traction Machine) instrument using the so-called traction test mode. In this mode, the friction coefficient is measured at a constant mean speed over a range of slide roll ratios (SRR) to give the traction curve. SRR=sliding speed/mean entrainment speed=2 (U1U2)/(U1+U2) in which U1 and U2 are the ball and disc speeds respectively

(11) The disc and ball used for the experiments were made of steel (AISI 52100), with a hardness of 750 HV and Ra<0.02 m. The diameter was 45.0 mm and 19.0 mm for the disc and the ball respectively. The tractions curves were run with 1.00 GPa contact pressure, 4 m/s mean speed and 70 C. temperature. The slide-roll ratio (SRR) was varied from 0 to 25% and the friction coefficient measured.

(12) Oil Compatibility Evaluation

(13) A method was developed in-house to determine oil compatibility. The oil and test material were mixed in 10/90, 50/50 and 90/10% w/w ratios respectively. The mixtures were mixed at room temperature by rolling for 12 hours. The mixtures' appearance was observed after homogenization and again after 24 hours. The test material is deemed compatible with the oil when no phase separation is observed after 24 hours for at least two of the ratios investigated.

Synthesis of the Polyalkylene Glycols

Example 1: Pluriol E400 with 12 Equivalents of C12 Epoxide and 20 Equivalents of Butylene Oxide (Random)

(14) A steel reactor (1.5 l) was loaded with polyethylene glycol 400 (MW 400) (0.2 mol, 80 g), and 3.23 g KOtBu (0.4 w %) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of butylene oxide and C12 epoxide (4.0 mol, 288 g BuO; 2.4 mol, 441 g C12 epoxide) was brought in dropwise during 10 h at 140 C. and under pressure of 6 bar. The reactor was stirred for 10 h at 140 C. and cooled to 80 C. The product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 30 g) and mixed on a rotary evaporator at 80 C. The purified product was obtained by filtration in a pressure strainer (Filtrations media: Seitz 900). Yield: 809 g, quantitative (Theor.: 809 g) OHZ: 33.6 mg KOH/g; (Theo.: 27.7 mg KOH/g); GPC: Mn: 3477; Mw: 3841;

Example 2: Pluriol E200 with 12 Equivalents of C12 Epoxide and 20 Equivalents Butylene Oxide (Random)

(15) A steel reactor (1.5 l) was loaded with polyethylene glycol 200 (MW 200) (0.2 mol, 80 g), and 3.07 g KOtBu (0.4 w %) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of butylene oxide and C12 epoxide (4.0 mol, 288 g BuO; 2.4 mol, 441 g C12 epoxide) was brought in dropwise during 8 h at 140 C. and under pressure of 6 bar. The reactor was stirred for 10 h at 140 C. and cooled to 80 C. The product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 30 g) and mixed on a rotary evaporator at 80 C. The purified product was obtained by filtration in a pressure strainer (Filtrations media: Seitz 900). Yield: 719 g, quantitative (Theor.: 769 g) OHZ: 32.0 mg KOH/g; (Theo.: 29.2 mg KOH/g); GPC: Mn: 3494; Mw: 3749;

Example 3: Pluriol E1000 with 36 Equivalents of C12 Epoxide and 60 Equivalents Propylene Oxide (Random)

(16) A steel reactor (1.5 l) was loaded with polyethylene glycol 1000 (MW 1000) (0.1 mol, 100 g), and 6.66 g CsOH 50% in water (0.3 w % to product) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of propylene oxide and C12 epoxide (6.0 mol, 348 g PO; 3.6 mol, 662 g C12 epoxide) was brought in dropwise during 10 h at 140 C. and under pressure of 6 bar. The reactor was stirred for 10 h at 140 C. and cooled to 80 C. The product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 30 g) and mixed on a rotary evaporator at 80 C. The purified product was obtained by filtration in a pressure strainer (Filtrations media: Seitz 900). Yield: 1125 g, quantitative (Theor.: 1110 g)

(17) OHZ: 18.8 mg KOH/g; (Theo.: 10.1 mg KOH/g);

(18) GPC: Mn: 5928; Mw: 7696;

Example 4: Pluriol E400 with 12 Equivalents of C12 Epoxide and 10 Equivalents Propylene Oxide (Random)

(19) A steel reactor (1.5 l) was loaded with polyethylene glycol 400 (MW 400) (0.25 mol, 100 g), and 1.6 g KOtBu (0.2 w %) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of propylene oxide and C12 epoxide (2.5 mol, 145 g PO; 3.0 mol, 552 g C12 epoxide) was brought in dropwise during 8 h at 140 C. and under pressure of 6 bar. The reactor was stirred for 10 h at 140 C. and cooled to 80 C. The product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 30 g) and mixed on a rotary evaporator at 80 C. The purified product was obtained by filtration in a pressure strainer (Filtrations media: Seitz 900). Yield: 773 g (Theor.: 802 g)

(20) OHZ: 37.1 mg KOH/g; (Theo.: 35.2 mgKOH/g);

(21) GPC: Mn: 3586; Mw: 3738; Mp: 3816.

Example 5: Pluriol E400 with 12 Equivalents of C12 Epoxide

(22) A steel reactor (1.5 l) was loaded with polyethylene glycol 400 (MW 400) (0.35 mol, 140 g), and 1.6 g KOtBu (0.2 w %) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar C12 epoxide (3.5 mol, 644 g) was brought in dropwise during 8 h at 140 C. and under pressure of 6 bar. The reactor was stirred for 10 h at 140 C. and cooled to 80 C. The product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 30 g) and mixed on a rotary evaporator at 80 C. The purified product was obtained by filtration in a pressure strainer (Filtrations media: Seitz 900). Yield: 748 g (Theor.: 784 g)

(23) OHZ: 46.8 mg KOH/g; (Theo.: 50.1 mgKOH/g);

(24) GPC: Mn: 2650; Mw: 2742; Mp: 2735.

(25) The oil compatibility and friction data are summarized in Table 1. The data demonstrate that the molecules derived from the present invention, namely polyalkylene glycols produced from the alkoxylation of polyethylene glycol (PEG) with epoxydodecane show compatibility with mineral oils and low viscosity polyalphaolefins whilst providing low friction coefficients (0.023 at 25% SRR in MTM experiments).

(26) TABLE-US-00002 TABLE 1 Low viscosity MTM Mineral oil Group PAO 6 Kinematic friction III compatibility at compatibility at viscosity Pour coefficient room temperature room temperature (mm.sup.2/s) Viscosity point at (oil/test material) (oil/test material) 40 C. 100 C. Index ( C.) 25% SSR 10/90 50/50 90/10 10/90 50/50 90/10 Example 1 190 26.7 176 41 0.021 Yes Yes Yes Yes Yes No Example 2 203 27.1 170 41 0.023 Yes Yes Yes Yes Yes Yes Example 3 366 53.2 212 36 0.020 Yes Yes Yes Yes Yes Yes Example 4 140 22.0 186 27 0.018 Yes Yes Yes Yes Yes Yes Example 5 112 17.9 178 9 0.015 Yes Yes Yes Yes Yes Yes