REFRIGERATOR OIL, AND WORKING FLUID COMPOSITION FOR REFRIGERATOR

Abstract

A refrigerating machine oil having a flash point of 130° C. or lower and a carbon residue of 10% residual oil of 0.02% by mass or more.

Claims

1. A refrigerating machine oil having a flash point of 130° C. or lower and a carbon residue of 10% residual oil of 0.02% by mass or more.

2. The refrigerating machine oil according to claim 1, comprising: a low-viscosity hydrocarbon oil having a kinematic viscosity at 40° C. of 6 mm.sup.2/s or lower; and a high-viscosity hydrocarbon oil having a kinematic viscosity at 40° C. of 200 mm.sup.2/s or higher.

3. The refrigerating machine oil according to claim 2, wherein a content of the low-viscosity hydrocarbon oil is 85% by mass or more based on the total amount of the refrigerating machine oil.

4. The refrigerating machine oil according to claim 2, wherein a content of the high-viscosity hydrocarbon oil is 10% by mass or less based on the total amount of the refrigerating machine oil.

5. The refrigerating machine oil according to claim 1, wherein the refrigerating machine oil has a 90% distillation temperature of 270° C. or lower.

6. A working fluid composition for a refrigerating machine oil comprising: the refrigerating machine oil according to claim 1; and a refrigerant.

7. The working fluid composition for a refrigerating machine oil of claim 6, wherein the refrigerant comprises a hydrocarbon.

Description

EXAMPLES

[0078] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[0079] Low-viscosity hydrocarbon oils 1 to 3 used in Examples and Comparative Examples are as follows. Since the aromatic content of these hydrocarbon oils was less than 1% by mass, chromatographic fractionation was not carried out, and hydrocarbon type analysis by the GC-TOFMS method described above was directly carried out by regarding all as saturated hydrocarbons. The characteristics of these low viscosity hydrocarbon oils are shown in Table 1.

[0080] Low-viscosity hydrocarbon oil 1: mineral oil-based hydrocarbon oil obtained by hydrorefining and fractionating a raw material hydrocracking gas oil containing a vacuum distillation residual oil (aromatic content <1% by mass, ASTM color: 0)

[0081] Low-viscosity hydrocarbon oil 2: mineral oil-based hydrocarbon oil obtained by hydrodesulfurizing and fractionating an atmospheric distillation distillate of crude oil (aromatic content <1% by mass, ASTM color: 0)

[0082] Low-viscosity hydrocarbon oil 3: mineral oil-based hydrocarbon oil obtained by hydrodesulfurizing and fractionating an atmospheric distillation distillate of crude oil (aromatic content <1% by mass, ASTM color: 0)

TABLE-US-00001 Low-viscosity hydrocarbon oil 1 2 3 Kinematic viscosity 40° C. mm.sup.2/s 2.44 2.32 2.357 100° C. 1.1 1.0 1.029 Density g/cm.sup.3 0.827 0.806 0.8013 Flash point °C 116 118 118 Pour point °C <-45 <-45 -25 Distillation characteristics IBP °C 242 242 244.5 T10 246 247.5 247.5 T50 249 250 250 T90 253 261 257.5 EP 282 292 278 T90-T10 7.0 13.5 10 Total distillation amount % by volume 99 99 98 Residual oil amount 1 1 1 Loss amount 0 0 1 Amount of C12-16 components % by mass 97.1 93.9 94.2 Amount of C13-C18 components % by mass 99.5 99.4 99.3 Amount of n-paraffin % by mass 1.2 9.6 23.6 Amount of paraffin % by mass 45 68 59 Amount of cycloparaffin % by mass 55 32 41 Paraffin / cycloparaffin 0.8 2.1 1.44

[0083] High-viscosity hydrocarbon oils 1 and 2 having the following characteristics were obtained by hydrorefining the solvent extracted raffinate of the deasphalted oil of vacuum distillation residual oil and solvent dewaxing.

[0084] High-viscosity hydrocarbon oil 1 (40° C. kinematic viscosity: 479.4 mm.sup.2/s, 100° C. kinematic viscosity: 31.72 mm.sup.2/s, viscosity index 97, flash point: >300° C., carbon residue: 0.51% by mass, ASTM color: L2.0)

[0085] High-viscosity hydrocarbon oil 2 (40° C. kinematic viscosity: 458 mm.sup.2/s, 100° C. kinematic viscosity: 31.2 mm.sup.2/s, viscosity index 98, flash point: >300° C., carbon residue: 0.5% by mass, ASTM color: L2.0)

[0086] These hydrocarbon oils were used in the compositions (% by mass based on the total amount of hydrocarbon oil) shown in Table 2. Refrigerating machine oils were prepared by mixing 98.3% by mass of each base oil and 1.7% by mass of a phosphorus-containing antiwear agent composed of a mixture of tricresyl phosphate and triphenyl phosphorothionate (all based on the total amount of the refrigerating machine oil). The hydrocarbon type analysis was performed on the hydrocarbon oil contained in each refrigerating machine oil, and the results are shown in Table 2. The characteristics of the each refrigerating machine oil are also shown in Table 2.

Evaluation of Antiwear Property

[0087] For antiwear property, seizure load was measured in accordance with ASTM D3233-73 using a Falex (pin / V block) tester under conditions of temperature 60° C. and rotational speed 290 rpm. The larger the seizure load, the better antiwear property. The results are shown in Table 2.

TABLE-US-00002 Example Comparative Example 1 2 3 4 5 6 1 2 Composition of hydrocarbon oil (% by mass) Low-viscosity 1 98 96 98 96 - - 100 - 2 - - - - 98 95 - 100 High-viscosity 1 2 4 - - 2 5 - - 2 - - 2 4 - - - - Flash point °C 116 116 116 116 118 118 116 118 Amount of C12-16 components % by mass 95.2 93.2 95.2 93.2 92.0 89.2 97.1 93.9 Amount of C13-C18 components % by mass 97.4 95.5 97.4 95.5 97.4 94.4 99.5 99.4 Amount of n-paraffin % by mass 1.2 1.2 1.2 1.2 9.4 9.1 1.2 9.6 Amount of paraffin % by mass 44 44 44 44 67 66 45 68 Amount of cycloparaffin % by mass 56 56 56 56 33 34 55 32 Paraffin / cycloparaffin 0.8 0.8 0.8 0.8 2.0 1.9 0.8 2.1 Carbon residue of 10% residual oil % by mass 0.1 0.21 0.1 0.2 0.1 0.25 <0.01 <0.01 Kinematic viscosity 40° C. mm.sup.2/s 2.61 2.79 2.61 2.79 2.52 2.80 2.44 2.32 100° C. 1.1 1.2 1.1 1.2 1.1 1.2 1.1 1.0

TABLE-US-00003 Example Comparative Example 1 2 3 4 5 6 1 2 Density g/cm.sup.3 0.827 0.829 0.828 0.829 0.808 0.811 0.827 0.806 Pour point °C <-45 <-45 <-45 <-45 <-45 <-45 <-45 <-45 Distillation characteristics IBP °C 242.5 241 242 241 242 242 242 242 T10 246 246 246 246 247.5 247.5 246 247.5 T50 249.5 249.5 249.5 249.5 250 250 249 250 T90 256.5 258 256 258.5 262 265 253 261 EP 284 285 285 284 294 295 282 292 T90-T10 10.5 12.0 10.0 12.5 14.5 17.5 7.0 13.5 Total distillation amount % by volume 97 96 97 95.5 97 95 97.5 97 Residual oil amount 3 4 3 4.5 3 5 2 3 Loss amount 0 0 0 0 0 0 0.5 0 Antiwear property Seizure load lbf 590 660 600 680 740 780 450 510

[0088] Furthermore, in each of Examples 5 and 6, the low-viscosity hydrocarbon oil 3 was used instead of the low-viscosity hydrocarbon oil 2 to prepare each of the refrigerating machine oils of Examples 7 and 8. In the obtained refrigerating machine oils of Examples 7 and 8, the amount of n-paraffin was larger and the pour point was slightly higher than those of each refrigerating machine oil of Examples 5 and 6, but equal or better antiwear property and further improved low friction property.

(Low Temperature Precipitation Test in Presence of Refrigerant)

[0089] The refrigerating machine oils of Examples 1 to 8 were subjected to a low-temperature precipitation test according to Appendix A of JIS K2211 (2009), using R600a that is a hydrocarbon refrigerant, as the refrigerant. In the mixed fluid of the refrigerating machine oils of Examples 1 to 8 and R600a, hair-like precipitates, granular precipitates, cloudiness, or cloudiness did not occur, and a tendency to precipitate at low temperatures was not observed, when the refrigerating machine oil / refrigerant ratio (mass ratio) was in the range of 1/99 to 99/1 and even when the mixed fluid was cooled to -40° C.