Lubricating oil

• US 20070027038A1
• Filed: 10/08/2004
• Published: 02/01/2007
• Est. Priority Date: 10/10/2003
• Status: Active Grant

• Current Assignee: Idemitsu Kosan Company Limited, Shigeyuki Mori
• Original Assignee: Idemitsu Kosan Company Limited, Shigeyuki Mori
• Inventors: Kamimura, Hideto, Mori, Shigeyuki
• Granted Patent: US 8,318,644 B2
• Time in Patent Office: Days
• US Class Current: 508/244
• CPC Class Codes: C10M 105/56 containing nitrogen
• CPC Class Codes: C10M 105/72 containing sulfur, selenium or tellurium
• CPC Class Codes: C10M 105/74 containing phosphorus
• CPC Class Codes: C10M 171/00 Lubricating compositions characterised by purely physical criteria, e.g. containing as base-material, thickener or additive, ingredients which are characterised exclusively by their numerically specified physical properties, i.e. containing ingredients which are physically well-defined but for which the chemical nature is either unspecified or only very vaguely indicated chemically defined ingredients C10M101/00 - C10M169/00; petroleum fractions C10M101/02, C10M121/02, C10M159/04
• CPC Class Codes: C10M 2201/0803 used as base material
• CPC Class Codes: C10M 2201/0853 used as base material
• CPC Class Codes: C10M 2201/0873 used as base material
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2207/283 of polyhydroxy compounds
• CPC Class Codes: C10M 2207/285 of aromatic polycarboxylic acids
• CPC Class Codes: C10M 2211/0445 used as base material
• CPC Class Codes: C10M 2213/06 Perfluoro polymers
• CPC Class Codes: C10M 2215/041 used as base material
• CPC Class Codes: C10M 2215/0425 used as base material
• CPC Class Codes: C10M 2215/064 Di- and triaryl amines
• CPC Class Codes: C10M 2215/2203 used as base material
• CPC Class Codes: C10M 2215/2245 used as base material
• CPC Class Codes: C10M 2219/0406 used as base material
• CPC Class Codes: C10M 2219/081 used as base material
• CPC Class Codes: C10M 2219/083 Dibenzyl sulfide
• CPC Class Codes: C10M 2219/101 : used as base material
• CPC Class Codes: C10M 2223/041 : Triaryl phosphates
• CPC Class Codes: C10N 2020/00 : Specified physical or chemical properties or characteristics, i.e. function, of component of lubricating compositions
• CPC Class Codes: C10N 2020/02 : Viscosity; Viscosity index
• CPC Class Codes: C10N 2020/077 : Ionic Liquids
• CPC Class Codes: C10N 2030/00 : Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
• CPC Class Codes: C10N 2030/02 : Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/06 : Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2030/08 : Resistance to extreme temperature
• CPC Class Codes: C10N 2030/12 : Inhibition of corrosion, e.g. anti-rust agents or anti-corrosives
• CPC Class Codes: C10N 2030/74 : Noack Volatility
• CPC Class Codes: C10N 2040/02 : Bearings
• CPC Class Codes: C10N 2040/08 : Hydraulic fluids, e.g. brake-fluids
• CPC Class Codes: C10N 2040/18 : in connection with recordings on magnetic tape or disc
• CPC Class Codes: C10N 2040/20 : Metal working
• CPC Class Codes: C10N 2040/22 : with essential removal of material , e.g. cutting, grinding or drilling
• CPC Class Codes: C10N 2040/24 : without essential removal of material , e.g. forming, gorging, drawing, pressing, stamping, rolling or extruding; Punching metal
• CPC Class Codes: C10N 2040/25 : Internal-combustion engines
• CPC Class Codes: C10N 2040/30 : Refrigerators lubricants or compressors lubricants
• CPC Class Codes: G04B 31/08 : Lubrication self-lubricated plastic bearings G04B31/016; lubrication of the escape wheel G04B15/14; lubrication of synchronous clockworks G04C15/009; lubrication devices and lubricant containers G04D5/00

Abstract

The invention provides a lube oil which exhibits low vapor pressure despite having low viscosity, is non-flammable, exhibits excellent heat resistance, has tribological characteristics equivalent to those of conventional hydrocarbon-based lube oils, and can be used for a long time under very severe conditions such as high temperature and vacuum.

The lube oil contains, as a base oil, an ionic liquid formed of a cation and an anion and having an ion concentration of 1 mol/dm³ or more.

Claims

1. A lube oil comprising, as a base oil, an ionic liquid formed of a cation and an anion and having an ion concentration of 1 mol/dm³ or more.

2. The lube oil as claimed in claim 1, wherein the ionic liquid has a total acid value of 1 mgKOH/g or less, and the lube oil contains the ionic liquid as a base oil, in an amount of 50 to 100 mass %.

3. The lube oil as claimed in claim 1, wherein the ionic liquid is represented by the following formula:

(Z^p+)_k(A<sup>q−

)</sup>_m

(wherein Z^p+ represents a cation;

A^q−

represents an anion;

each of p, q, k, m, pxk, and qxm is an integer of 1 to 3, with the relationship pxk=qxm being satisfied; and

, when k or m is 2 or more, Z or A may be identical to or different from each other).

4. The lube oil as claimed in claim 3, wherein the ionic liquid is represented by the formula Z⁺A⁻

(wherein Z⁺ represents a cation and A⁻

represents an anion) and has a total acid value of 1 mgKOH/g or less, and the lube oil contains the ionic liquid as a base oil, in an amount of 50 to 100 mass %.

5. The lube oil as claimed in claim 4, wherein the ionic liquid is a mixture of two or more ionic liquids.

6. The lube oil as claimed in claim 5, wherein the mixture contains one Z⁺ species and two or more A⁻

species, two or more Z⁺ species and one A⁻

species, or two or more Z⁺ species and two or more A⁻

species.

7. The lube oil as claimed in claim 4, wherein the cation (Z⁺) forming the ionic liquid is represented by any of the following formulas:

(wherein each of R¹ to R¹², which may be identical to or different from one another, represents a group selected from among a hydrogen atom, C1 to C18 alkyl groups which may each have an ether bond, and C1 to C 18 alkoxy groups).

8. The lube oil as claimed in claim 7, wherein the cation (Z⁺) forming the ionic liquid is represented by any of the following formulas:

(wherein each of R¹ to R¹², which may be identical to or different from one another, represents a group selected from among a hydrogen atom, C1 to C18 alkyl groups which may each have an ether bond, and C1 to C18 alkoxy groups).

9. The lube oil as claimed in claim 4, wherein the anion (A⁻

forming the ionic liquid is selected from among BF₄⁻

, PF₆⁻

, C_nH_(2n+1)OSO₃⁻

, (C_nF_(2n+1-x)H_x)SO₃⁻

(C_nF_(2n+1-x)H_x)COO⁻

, NO₃⁻

, CH_3SO3⁻

, (CN)₂N⁻

, HSO₃⁻

, C₆H₅SO₃⁻

, CH₃(C₆H₄)SO₃⁻

, I⁻

, I₃⁻

, F(HF)_n⁻

, ((C_nF_(2n+1-x)H_x)Y¹O_z)₃C⁻

, ((C_nF_(2n+1-x)H_x)Y¹O_z)₂N⁻

(wherein Y¹ represents a carbon atom or a sulfur atom;

when a plurality of Y¹s are present, these may be identical to or different from one another;

a plurality of (C_nF_(2n+1-x)H_x)Y¹O_z groups may be identical to or different from one another);

n is an integer of 1 to 6;

x is an integer of 0 to 13; and

z is an integer of 1 to 3 when Y¹ is a carbon atom and 0 to 4 when Y¹ is a sulfur atom), B(C_mY²_(2m+1)₄⁻

, P(C_mY²_(2m+1)₆⁻

(wherein Y² is a hydrogen atom or a fluorine atom;

when a plurality of Y²s are present, these may be identical to or different from one another;

a plurality of (C_mY²_(2m+1) groups may be identical to or different from one another); and

m is an integer of 0 to

     6), and anions represented by the following formula;

(wherein each of R¹³ to R¹⁷, which may be identical to or different from one another, represents a group selected from a hydrogen atom and (C_nF_(2n+1-x)H_x); and

n and x have the same meanings as defined above).

10. The lube oil as claimed in claim 9, wherein the anion (A⁻

) forming the ionic liquid is selected from among PF₆⁻

, C_nH_(2n+1)OSO₃⁻

(C_nF_(2n+1-x)H_x)SO₃⁻

, (C_nF_(2n+1-x)H_x)COO⁻

, NO₃⁻

, CH₃SO₃⁻

, (CN)₂N⁻

, HSO₃⁻

, ((C_nF_(2n+1-x)H_x)Y¹O_z)₂N⁻

(wherein Y¹ represents a carbon atom or a sulfur atom;

when a plurality of Y¹s are present, these may be identical to or different from one another;

n is an integer of 1 to 6;

x is an integer of 0 to 13; and

z is an integer of 1 to 3 when Y¹ is a carbon atom and 0 to 4 when Y¹ is a sulfur atom), and anions represented by the following formula;

wherein each of R¹³ to R¹⁷, which may be identical to or different from one another, represented a group selected from a hydrogen atom and (C_nF_(2n+1-x)H_x); and

n and x have the defined above).

11. The lube oil as claimed in claim 10, wherein the anion (A⁻

) forming the ionic liquid is selected from among C_nH_(2n+1)OSO₃⁻

, (C_nF_(2n+1-x)H_x)SO₃⁻

, (C_nF_(2n+1-x)H_x)COO⁻

, NO₃⁻

, CH₃SO₃⁻

, (CN)₂N⁻

, HSO₃⁻

, (wherein n is an integer of 1 to 6; and

x is an integer of 0 to

     13), and anions represented by the following formula;

wherein each of R¹³ to R¹⁷, which may be identical to or different from one another, selected from a hydrogen atom and (C_nF_(2n+1-x)H_x); and

n and x have the defined above).

12. The lube oil as claimed in claim 4, wherein the ionic liquid does not contain a cation represented by the following formula:

(wherein each of R¹ to R⁵, which may be identical to or different from one another, represents a group selected from among a hydrogen atom, C1 to C 18 alkyl groups which may each have an ether bond, and C1 to C 18 alkoxy groups), F⁻

, Cl⁻

, Br⁻

, or BF₄⁻

.

15. The lube oil as claimed in claim 1, wherein the ionic liquid has a kinematic viscosity of 1 to 1,000 mm²/s as determined at 40°

C.

16. The lube oil as claimed in claim 1, wherein the ionic liquid has a pour point of −

10°

C. or lower.

17. The lube oil as claimed in claim 1, wherein the ionic liquid has a viscosity index of 80 or more.

18. The lube oil as claimed in claim 1, wherein the ionic liquid has a flash point of 200°

C. or higher.

19. The lube oil as claimed in claim 1, which contains at least one member selected from an antioxidant and an extreme pressure agent.

20. The lube oil as claimed in claim 1, which has a water content of 500 ppm by mass or less on the basis of the lube oil.

21. A method for regulating lubrication characteristics, wherein the method comprises applying an electric field to the lube oil as claimed in claim 1.

22. A lubrication characteristic regulating apparatus for regulating the lubrication characteristic of a contact region between two lubrication member, characterized in that wherein the apparatus is adapted, in use, for interacting with the lube oil claimed in claim 1 above which is introduced into said contact region, and which apparatus comprises a pair of electrodes which are placed so as to sandwich the contact region, the electrodes being in contact or not in contact with the lubrication members and being provided for applying an electric field to the contact region.

13. A lube oil comprising, as a base oil, an ionic liquid formed of a zwitter ion in which a cation and an anion are linked via a covalent bond and which has a total acid value of 1 mgKOH/g or less, in an amount of 50 to 100 mass %.

14. The lube oil as claimed in claim 13, wherein the ionic liquid is represented by the following formula:

(wherein each of R¹ to R¹² which may be identical to or different from one another, represents a group selected from among a hydrogen atom, C1 to C18 alkyl groups which may each have an ether bond, and C1 to C18 alkoxy groups; and

at least one of R1 to R¹² is —

(CH₂)_n—

SO₃⁻

or —

(CH₂)_n—

COO⁻

(wherein n is an integer of 0 or greater such that the number of carbon atoms of each alkyl group falls within a range of 1 to

     18)).