Hydraulic composition for extreme cold

Abstract

The invention relates to the field of lubricants and provides a lubricating composition comprising at least one base oil, the kinematic viscosity of which measured at 40° C. does not exceed 10 mm.sup.2/s and the pour point of which does not exceed −50° C., and at least one thickener, said lubricating composition having a pour point not exceeding −55° C.

Claims

1. A lubricant composition comprising: at least one base oil having kinematic viscosity measured at 40° C. less than or equal to 10 mm.sup.2/s and having a pour point lower than or equal to −50° C.; and at least one polyalkylene glycol (PAG) thickener comprising at least 50 weight % of butylene oxide repeat units and having kinematic viscosity measured at 100° C. according to standard ASTM D445 (2015) comprised between 50 and 500 mm2/s, said kinematic viscosity measured at 40 ° C. according to standard ASTM D445 (2015) comprised between 500 and 4500 mm2/s, and a viscosity index measured according to standard ASTM D2270 (2012) comprised between 160 and 300; said lubricant composition having a pour point lower than or equal to −55° C.

2. The composition according to claim 1, further comprising a viscosity index improver.

3. The composition according to claim 1, wherein the base oil is selected from the group consisting of Group III, IV, and V oils.

4. The composition according to claim 1, wherein the base oil comprises more than 90 weight % of iso-paraffins, and less than 300 ppm of aromatics.

5. The composition according to claim 3, wherein the iso-paraffin/n-paraffin weight ratio characterizing the base oil is higher than or equal to 12:1.

6. The composition according to claim 1, wherein the base oil has kinematic viscosity measured at 40° C. of between 1 and 10 mm.sup.2/s.

7. The composition according to claim 1, comprising from 50 to 85 weight % of base oil relative to the total weight of the composition.

8. The composition according to claim 1, wherein the PAGs comprise at least 80 weight % of butylene oxide repeat units.

9. The composition according to claim 1, wherein the content of active thickening material is between 5 and 50 weight % relative to the total weight of the lubricant composition.

10. The composition according to claim 1, comprising from 5 to 20 weight % of active viscosity improving material relative to the total weight of the composition.

11. A method of lubricating industrial machinery at temperatures lower than −40° C. comprising contacting mechanical parts of the industrial machinery needing an industrial lubricant or hydraulic fluid to be lubricated with a lubricant composition comprising: a base oil having kinematic viscosity measured at 40° C. less than or equal to 10 mm.sup.2/s and having a pour point lower than or equal to −50° C.; and a polyalkylene glycol thickener comprising at least 50 weight % of butylene oxide repeat units and having kinematic viscosity measured at 100° C. according to standard ASTM D445 (2015) comprised between 50 and 500 mm.sup.2/s, kinematic viscosity measured at 40° C. according to standard ASTM D445 (2015) comprised between 500 snf 4500 mm.sup.2/s, and a viscosity index measured according to standard ASTM D2270 (2012) comprised betweeen 160 and 300said lubricant composition having a pour point lower than or equal to −55° C.

12. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the base oil is selected from the group consisting of Group III oils, Group IV oils, and Group V oils.

13. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the base oil comprises more than 90 weight % of iso-paraffins, and less than 300 ppm of aromatics.

14. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 13, wherein the iso-paraffin/n-paraffin weight ratio characterizing the base oil is higher than or equal to 12:1.

15. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 13, wherein the iso-paraffin/n-paraffin weight ratio characterizing the base oil is higher than or equal to 15:1.

16. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 13, wherein the iso-paraffin/n-paraffin weight ratio characterizing the base oil is higher than or equal to 20:1.

17. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the base oil has kinematic viscosity measured at 40° C. having a range selected from the group consisting of (a) between 1 and 10 mm.sup.2/s; (b) between 2 and 10 mm.sup.2/s′ (c) between 2 and 8 mm.sup.2/s; and (d) between 2 and 4 mm.sup.2/s.

18. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the lubricating composition comprises from 50 to 85 weight % of base oil relative to the total weight of the composition.

19. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the lubricating composition comprises from 55 to 80 weight % of base oil relative to the total weight of the composition.

20. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the lubricating composition comprises from 60 to 75 weight % of base oil relative to the total weight of the composition.

21. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the PAGs comprise at least 80 weight % of butylene oxide repeat units.

22. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the content of active thickening material is between 5 and 50 weight % relative to the total weight of the lubricant composition.

23. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the content of active thickening material is between 10 and 45 weight % relative to the total weight of the lubricant composition.

24. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the lubricating composition comprises from 5 to 20 weight % of active viscosity improving material relative to the total weight of the composition.

25. The method for lubricating parts of industrial machinery at temperatures lower than −40° C. according to claim 11, wherein the lubricating composition comprises from 5 to 15 weight % of active viscosity improving material relative to the total weight of the composition.

Description

EXAMPLE 1

Preparation of Lubricant Compositions CL1, CL2 and CL3 of the Invention

(1) The different components of the lubricant compositions of the invention are mixed together according to the product types and amounts given in Table 1.

(2) TABLE-US-00002 TABLE 1 Lubricant Lubricant Lubricant com- com- com- position position position CL1 of the CL2 of the CL3 of the invention invention invention (wt. %) (wt. %) (wt. %) Group V oil: KV40 = 2.49 mm.sup.2/ 51.02 0 48.02 s and pour point = −81° C.) Group IV oil: KV40 = 5.2 mm.sup.2/ 0 62.02 0 s and pour point = −63° C.) (Thickener) PAG, KV100 = 43.00 32.00 41.00 680 = 77 mm.sup.2/s .sup.(1) Polyalkylmethacrylate, 5.00 5.00 5.00 KV100 = 1200 mm2/s 0 5.00 Lubricity modifier .sup.(2) 0 Additive package 0.98 0.98 0.98 .sup.(1) PAG, KV100 = 680 mm.sup.2/s commercially available from DOW under the trade nameUCON-OSP 680. .sup.(2) Lubricity modifier being 2-ethylhexyl sebacate. .sup.(3) The additive package is a conventional, commercial additive package particularly comprising a defoamer, anti-corrosion additive, antioxidant additive.

EXAMPLE 2

Measurement of the Characteristics of Lubricant Compositions CL1, CL2 and CL3

(3) The characteristics of lubricant compositions CL1, CL2 and CL3 (kinematic viscosity, viscosity index and pour point) are given in Table 2.

(4) TABLE-US-00003 TABLE 2 CL1 CL2 CL3 Kinematic viscosity at 40° C. (mm.sup.2/s) 29.7 30.5 30.1 Kinematic viscosity at 100° C. (mm.sup.2/s) 8.53 7.97 8.52 Calculated viscosity index 289 252 284 Pour point (° C.) −60 −57 −60 Loss of viscosity at 100° C. Less than Less than Less than after 20 h KRL shear 15% 15% 15%

(5) Kinematic viscosities at 40° C. and 100° C. were measured according to standard ISO 3104 of 15 Jul. 1997.

(6) The lubricant compositions of the invention have good viscosifying properties in particular at 40 and 100° C.

(7) The viscosity index was calculated according to standard ISO 2909 of 15 Dec. 2002. The pour point was measured according to standard ISO 3016 of 1 Aug. 1994.

(8) Loss of viscosity at 100° C. after 20 h KRL shear was measured according to standard DIN 51350-6.

(9) Loss of viscosity at 100° C. after 20 h KRL shear shows that the lubricant compositions of the invention have very good stability under shear.

(10) The lubricant compositions of the invention are characterized by a pour point lower than or equal to −57° C., a viscosity index of between 252 et 289 and very low loss of viscosity after KRL shear.

(11) These characteristics show that the lubricant compositions of the invention can be used as hydraulic fluid in polar climates. In addition, with their excellent shear resistance (KRL test), the lubricant compositions maintain their properties when in use.