LUBRICANT COMPOSITION WITH A COMBINATION OF PARTICLES

Abstract

The present invention relates to a lubricant composition comprising at least one graphite particle and at least one polytetrafluoroethylene particle.

It also relates to the use of said composition for the lubrication of gears, in particular of industrial gears.

Claims

1. A lubricant composition comprising at least one graphite particle and at least one polytetrafluoroethylene particle.

2. The lubricant composition of claim 1, comprising at most 20% by weight of particles in relation to the total weight of said composition.

3. The lubricant composition of claim 1, comprising at most 20% by weight of particles in relation to the total weight of said composition.

4. The lubricant composition of claim 1, wherein the particles have a particle size comprised between 300 nm and 5 μm.

5. The lubricant composition of claim 1, wherein the particles have a particle size comprised between 50 nm and 400 nm.

6. The lubricant composition of claim 1, comprising at least one oil of lubricating viscosity.

7. The lubricant composition of claim 1, comprising at least one additive.

8. (canceled)

9. A method for lubricating gears, in particular industrial gears, comprising a step of contacting at least one gear with the lubricant composition of claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 represents the WSD on worn balls with and without the inclusion of graphite particles (KS4) in a commercial oil suitable for use in carter (CEP), at various loads.

[0059] The curve with squares corresponds to the use of CEP (lubricant alone) and the curve with triangles corresponds to the use of CEP together with 1% by weight of graphite particles (KS4).

[0060] FIG. 2 represents the WSD on worn balls with and without the inclusion of graphite particles (KS4) and PTFE particles (NanoFlon, NF) in CEP, at various loads.

[0061] The curve in continuous line with squares corresponds to the use of CEP (lubricant alone); the curve in dotted line with circles corresponds to the use of CEP together with 10% by weight of NF particles; the curve in continuous line with triangles .Math. corresponds to the use of CEP together with 1% by weight of KS4 particles; and the curve in continuous line with triangles .box-tangle-solidup. corresponds to the use of CEP together with 9% by weight of NF particles and 1% by weight of KS4 particles.

[0062] FIG. 3 represents the weld load for CEP oil with different combinations of NF and KS4.

[0063] FIG. 4 represents the WSD on worn balls with and without the inclusion of graphite particles (KS4) in a commercial oil suitable for use in carter (CSH), at various loads.

[0064] The curve with squares corresponds to the use of CSH (lubricant alone) and the curve with triangles corresponds to the use of CSH together with 1% by weight of KS4 particles.

[0065] FIG. 5 represents the WSD on worn balls with and without the inclusion of KS4 particles and NF particles (individually and simultaneously) in CSH, at various loads.

[0066] The curve with squares corresponds to the use of CSH alone; the curve with triangles .Math. corresponds to the use of CSH together with 1% by weight of KS4 particles; the curve with circles corresponds to the use of CSH together with 10% by weight of NF particles; and the curve with triangles .box-tangle-solidup. corresponds to the use of CSH together with 9% by weight of NF particles and 1% by weight of KS4 particles.

[0067] FIG. 6 represents the weld load for CSH with different combinations of NF and KS4.

DETAILED DESCRIPTION

EXAMPLES

Materials

[0068] Graphite particles (P1) are TIMCAL TIMREX® KS4 Primary Synthetic Graphite.

[0069] PTFE particles (P2) are Shamrock NanoFlon.

[0070] The lubricant oils are either 2 commercially available oils suitable for use in carter CEP and CSH.

Example 1: Effect on AW and EP Property of CEP Oil Due to Addition of 1% KS4 Particles

1.1. Effect on Anti-Wear Property

[0071] Anti-wear tests were conducted as per CONOMO standards on 150, 200 and 250 kg respectively.

[0072] FIG. 1 delineates the WSD on worn balls with and without the inclusion of KS4 in carter oils, while FIG. 2 compares these results with the inclusion of NanoFLon.

[0073] The 4 ball test (CONOMO standard) is carried out (speed—1500 rpm, at ambient temperature; Time—1 min).

Results

[0074] a) It appears from FIG. 1 that the minimum value of WSD is 1.26 mm.

[0075] FIG. 1 also shows that with an increase in load, the wear scar increased commensurately.

[0076] Moreover, this figure shows that inclusion of KS4 deteriorated the performance at every load.

[0077] The results may be summarized as shown in the below table.

TABLE-US-00001 TABLE 1 % increase in WSD due to addition of 1% KS4 in Carter EP 68 Load 150 kg 200 kg % increase/deterioration in performance 44.4% 50.7% [0078] b) It appears from FIG. 2 that the minimum value of WSD is 0.53 mm.

[0079] FIG. 2 also shows that with an increase in load, the wear scar increased commensurately.

[0080] Moreover, this figure shows that inclusion of KS4 deteriorated the performance at every load, whereas the inclusion of NanoFLon or NanoFLon+KS4 leads to improvement in performance.

[0081] The percentage in improvement is shown below:

TABLE-US-00002 Load 150 kg 200 kg 250 kg CEP + 10% NF 23%   18% .sup. 22% CEP + 9% NF + 1% KS4 27% 18.65% 21.6%

1.2. Effect on Weld Load

[0082] FIG. 3 shows the effect on Weld load (WL) of oil due to addition of 1% KS4 in CEP.

[0083] The 4 ball test is carried out according to the following parameters (IP 239): speed—1,450 rpm, at ambient temperature; Time—60 s).

Results

[0084] It appears from FIG. 3 that the range of WL is 2,453 to 9,810 N.

[0085] FIG. 3 also shows that the addition of 1% KS4 reduced WL by 37.5% compared to the oil alone.

[0086] It also shows that addition of 10% NF lead to increase in weld load by 100% and that addition of KS4 with NanoFLon lead to further increase to a minimum load of 1000 kg in Weld load of oils.

Example 2: Effect on AW and EP Property of CSH Due to Addition of 1% KS4

[0087] Particles

2.1. Effect on Anti-Wear Property

[0088] FIG. 4 delineates the WSD on worn balls with and without the inclusion of KS4 in carter oils, while FIG. 5 compares these results with the inclusion of NanoFLon.

[0089] The carried out test is the same as the one described in example 1.

Results

[0090] a) It appears from FIG. 4 that the minimum value of WSD is 0.52 mm.

[0091] FIG. 4 also shows that with an increase in load, the wear scar increased commensurately.

[0092] Moreover, this figure shows that inclusion of KS4 has no significant effect on WSD when compared to parent oil. [0093] b) It appears from FIG. 5 that the minimum value of WSD is 0.52 mm.

[0094] FIG. 5 also shows that with an increase in load, the wear scar increased commensurately.

[0095] Moreover, this figure shows that inclusion of KS4 appears to have no significant effect on WSD, whereas the inclusion of 10% NF leads to improvement in performance at higher loads.

2.2. Effect on Weld Load

[0096] FIG. 6 shows the effect on Weld load (WL) of oil due to addition of 1% KS4 in CSH.

[0097] The 4 ball test is carried out according to the following parameters (IP 239): speed—1,450 rpm, at ambient temperature; Time—60 s).

Results

[0098] It appears from FIG. 6 that the range of WL is 2,747 to 6,082 N.

[0099] FIG. 6 also shows that KS4 alone has no effect on EP performance of CSH.

[0100] It also shows that addition of 10% NF lead to increase in weld load by 98% and that addition of KS4 with NanoFLon lead to further increase to a minimum load of 1,000 kg in weld load of oils.