Use of polytetrahydrofuranes in lubricating oil compositions

Abstract

Lubricating oil compositions comprise one or more polytetrahydrofuranes that are prepared by alkoxylating polytetrahydrofurane with at least one C8-C30 epoxy alkane.

Claims

1. A lubricating oil composition comprising an alkoxylated polytetrahydrofurane of general formula (II): ##STR00011## 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 1 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 75, p is an integer in the range of 0 to 75, k is an integer in the range of 2 to 30, R.sup.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.sup.2 denotes CH.sub.2 CH.sub.3, and R.sup.3 identical or different, denotes a hydrogen atom or CH.sub.3, 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. The lubricating oil composition according to claim 1, wherein k is an integer in the range of 3 to 25.

3. The lubricating oil composition according to claim 1, wherein the alkoxylated polytetrahydrofurane has a weight average molecular weight Mw in the range of 500 to 20000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

4. The lubricating oil composition according to claim 1, wherein (m+m) is in the range of 3 to 65.

5. The lubricating oil composition according to claim 1, wherein the ratio of (m+m) to k is in the range of 0.3:1 to 6:1.

6. The lubricating oil composition according to claim 1, wherein m is an integer in the range of 1 to 25 and m is an integer in the range of 1 to 25.

7. The lubricating oil composition according to claim 1, wherein R.sup.1 denotes an unsubstituted, linear alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms.

8. The lubricating oil composition according to claim 1, wherein R.sup.3 is CH.sub.3.

9. The lubricating oil composition according to claim 1, 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 45, n is an integer in the range of 3 to 45, (n+n) is an integer in the range of 6 to 90, p is an integer in the range of 0 to 75, p is an integer in the range of 0 to 75, k is an integer in the range of 3 to 25, R.sup.1 is an unsubstituted, linear alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms, R.sup.2 is CH.sub.2CH.sub.3, and R.sup.3 is CH.sub.3.

10. The lubricating oil composition according to claim 9, wherein the ratio of (m+m) to k is in the range of 0.3:1 to 6:1 and the ratio of (n+n) to k is in the range of 1.5:1 to 10:1.

11. The lubricating oil composition according to claim 1, 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 0 to 45, n is an integer in the range of 0 to 45, 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 90, k is an integer in the range of 3 to 25, R.sup.1 is an unsubstituted, linear alkyl radical having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 carbon atoms, R.sup.2 is CH.sub.2-CH.sub..3, and R.sup.3 is CH.sub.3.

12. The lubricating oil composition according to claim 11, wherein the ratio of (m+m) to k is in the range of 0.3:1 to 6:1 and the ratio of (p+p) to k is in the range of 1.5:1 to 10:1.

13. The lubricating oil composition according to claim 1 having a friction coefficient in the range of 0.003 to 0.030 at 25% slide roll ratio (SRR) determined using mini-traction machine (MTM) measurements at 70 C. and 1 GPa.

14. The lubricating oil composition according to claim 1, which is effective for enhancing friction modification properties of one or more of the following: light, medium and heavy duty engine oils, industrial engine oils, marine engine oils, automotive engine oils, crankshaft oils, compressor oils, refrigerator oils, hydrocarbon compressor oils, very low-temperature lubricating oils and fats, high temperature lubricating oils and fats, wire rope lubricants, textile machine oils, refrigerator oils, aviation and aerospace lubricants, aviation turbine oils, transmission oils, gas turbine oils, spindle oils, spin oils, traction fluids, transmission oils, plastic transmission oils, passenger car transmission oils, truck transmission oils, industrial transmission oils, industrial gear oils, insulating oils, instrument oils, brake fluids, transmission liquids, shock absorber oils, heat distribution medium oils, transformer oils, fats, chain oils, minimum quantity lubricants for metalworking operations, oil to the warm and cold working, oil for water-based metalworking liquids, oil for neat oil metalworking fluids, oil for semi-synthetic metalworking fluids, oil for synthetic metalworking fluids, drilling detergents for the soil exploration, hydraulic oils, in biodegradable lubricants or lubricating greases or waxes, chain saw oils, release agents, moulding fluids, gun, pistol and rifle lubricants or watch lubricants, and food grade approved lubricants.

15. A method of reducing friction in an engine comprising obtaining a lubricating oil composition comprising at least one alkoxylated polytetrahydrofurane according to claim 1, and contacting the lubricating oil composition with surfaces of the engine.

16. A method of enhancing friction modification properties of a lubricating oil composition in the lubrication of a mechanical device comprising formulating said lubricating oil composition with at least one alkoxylated polytetrahydrofurane according to claim 1.

17. The lubricating oil composition according to claim 1, which is effective for reducing friction between moving surfaces of an engine.

18. The lubricating oil composition according to claim 1, wherein k is an integer in the range of 5 to 20.

19. The lubricating oil composition according to claim 18, wherein the alkoxylated polytetrahydrofurane has a weight average molecular weight Mw in the range of 4000 to 7000 g/mol determined according to DIN 55672-1 (polystyrene calibration standard).

20. A lubricating oil composition comprising: at least one base stock selected from the group consisting of: mineral oils (Group I, II or III oils), polyalphaolefins (Group IV oils), polymerized and interpolymerized olefins, alkyl naphthalenes, alkylene oxide polymers, silicone oils, phosphate esters and carboxylic acid esters (Group V oils); one or more additives; and an alkoxylated polytetrahydrofurane of general formula (II): ##STR00012## 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 1 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 75, p is an integer in the range of 0 to 75, k is an integer in the range of 2 to 30, R.sup.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.sup.2 denotes CH.sub.2 CH.sub.3, and R.sup.3 identical or different, denotes a hydrogen atom or CH.sub.3, 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.

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.

(14) Synthesis of the Polyalkylene Glycols

Example 1: PolyTHF 650 with 20 Equivalents of C12 Epoxide

(15) A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 650) (0.2 mol, 130 g), and 3.4 g KOtBu was mixed and the reactor was purged with nitrogen. The reactor was heated under vacuum (10 mbar) and heated to 140 C. for 0.25 h. Then again nitrogen was loaded. At a pressure of 2 bar 50 g C12 epoxide was brought in dropwise at 140 C. 686 g C12 epoxide of total (736 g; 4.0 mol) was added during 10 h at 140 C. and under pressure of 6 bar. Yield: 874 g, quantitative (Theor.: 866 g) OHZ: 28.2 mg KOH/g.

Example 2: PolyTHF 650 with 12 Equivalents of C12 Epoxide and 20 Equivalents of Butylene Oxide (Block)

(16) A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 250) (0.2 mol, 130 g), and 3.4 g KOtBu was mixed and the reactor was purged with nitrogen. The reactor was heated under vacuum (10 mbar) and heated to 140 C. for 0.25 h. Then again nitrogen was loaded. At a pressure of 2 bar 50 g C12 epoxide was brought in dropwise at 140 C. 390 g C12 epoxide of total (441 g; 2.4 mol) was added during 5 h at 140 C. and under pressure of 6 bar. Then butylene oxide (288 g, 4.0 mol) was added within 4 h at 140 C. 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 Amboso (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: 866 g, quantitative (Theor.: 859 g) OHZ: 30.1 mg KOH/g

Example 3: PolyTHF 650 with 12 Equivalents of C12 Epoxide and 20 Butylene Oxide (Random)

(17) A steel reactor (5 l) was loaded with polytetrahydrofurane (MW 250) (0.732 mol, 476 g), and KOtBu (12.6 g) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of butylene oxide and C12 epoxide (14.64 mol, 1104 g butylene oxide; 8.8 mol, 1617 g C12 epoxide) was brought in dropwise during 30 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 reactor was cooled to 80 C. and the product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 60 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: 3077 g (96%) (Th.: 3200 g), OHZ: 31.4 mg KOH/g

Example 4: PolyTHF 650 with 12 Equivalents of C12 Epoxide and 20 Equivalents of Propylene Oxide (Random)

(18) A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 650) (0.2 mol, 130 g), and KOtBu (3.21 g) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of propylene oxide and C12 epoxide (4.0 mol, 232 g PO; 2.4 mol, 441 g C12 epoxide) was brought in dropwise during 7 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 reactor was cooled to 80 C. and the product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 60 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: 800 g (quantitative) (Th.: 803 g), OHZ: 30.8 mgKOH/g.

Example 5: PolyTHF 1000 with 18 Equivalents of C12 Epoxide and 30 Equivalents of Butylene Oxide (Random)

(19) A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 1000) (0.1 mol, 100 g), and KOtBu (2.59 g) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of butylene oxide and C12 epoxide (3.0 mol, 216 g butylene oxide; 1.8 mol, 331 g C12 epoxide) was brought in dropwise during 5 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 reactor was cooled to 80 C. and the product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 60 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: 661 g (quantitative) (Th.: 647 g), OHZ: 24.7 mg KOH/g

Example 6: PolyTHF 1000 with 36 Equivalents of C12 Epoxide and 60 Equivalents of Butylene Oxide (Random)

(20) A steel reactor (1.5 l) was loaded with polytetrahydrofurane (MW 1000) (0.1 mol, 100 g), and KOtBu (4.78 g) was mixed and the reactor was purged with nitrogen. At a pressure of 2 bar a mixture of butylene oxide and C12 epoxide (6.0 mol, 432 g butylene oxide; 3.6 mol, 662 g C12 epoxide) was brought in dropwise during 11 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 reactor was cooled to 80 C. and the product was stripped by nitrogen. Then the product was discharged and mixed with Ambosol (magnesium silicate, 60 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: 1236 g (quantitative) (Th.: 1194 g), OHZ: 9.4 mg KOH/g

Example 7: PolyTHF 650 with 4 Equivalents of C12 Epoxide and 40 Equivalents of Butylene Oxide (Random)

(21) The oil compatibility and friction data are summarized in Table 2. The data demonstrate that the molecules derived from the present invention, namely polyalkylene glycols produced from the alkoxylation of polytetrahydrofuran (p-THF) with C12 epoxide show compatibility with mineral oils and low viscosity polyalphaolefins whilst providing low friction coefficients (0.025 at 25% SRR in MTM experiments).

(22) Oil compatible materials presented in Examples 1 to 7 consistently exhibit friction coefficient equal or lower than 0.025 at 25% SRR in the MTM experiments.

(23) TABLE-US-00002 TABLE 1 Starting alcohol Random/Block PO BuO C12 epoxide OHZ [mgKOH/g] Mn Mw PD Example 1 pTHF 650 block 20 28.2 4517 4923 1.09 Example 2 pTHF 650 block: 1. C12 20 12 30.1 3861 4602 1.19 epoxide, 2. BuO Example 3 pTHF 650 random 20 12 31.4 4720 4650 1.42 Example 4 pTHF 650 random 20 12 30.8 4660 5074 1.09 Example 5 pTHF1000 random 30 18 24.7 4551 5667 1.24 Example 6 pTHF1000 random 60 36 9.4 5204 6629 1.27 Example 7 pTHF 650 block 40 4 27 4872 5369 1.10 Comparative examples Example 8* polybutylene glycol (propandiol + 43 BO) Example 9* p-THF 1000 + 20 PO Example 10* p-THF 1000 + 10 PO + 13 EO Example 11* p-THF 250 Example 12* p-THF 650 Example 13* p-THF 1000

(24) TABLE-US-00003 TABLE 2 Mineral oil Group III compatibility Low viscosity PAO Kinematic at room compatibility at viscosity Pour MTM friction temperature room temperature (mm.sup.2/s) Viscosity point coefficient 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 1 289 40 192 12 0.015 Yes Yes Yes No Yes Yes Example 2 284 37 182 11 0.020 Yes Yes Yes Yes Yes Yes Example 3 392 50 189 42 0.019 Yes Yes Yes Yes Yes Yes Example 4 268 38 195 35 ---0.016 Yes Yes Yes Yes Yes Yes Example 5 412 52 191 43 0.018 Yes Yes Yes Yes Yes Yes Example 6 441 56 195 39 0.019 Yes Yes Yes Yes Yes Yes Example 7 539 64 192 42 0.022 Yes Yes Yes Comparative examples Example 8* 304 35 159 39 0.034 Yes Yes Yes No No No Example 9* 348 50 207 9 0.013 No No No No No No Example 10* 359 57 227 6 0.008 No No No No No No Example 11* 54 7 94 42 0.007 No No No No No No Example 12* 159 22 165 3 0.007 No No No No No No Example 13* 291 40 193 6 0.007 No No No No No No