Refrigerating machine oil for HFOs refrigerant, working fluid composition and application
By using caprylic acid instead of isooctanoic acid to prepare polyol esters, the problem of insufficient oil film strength after mixing HFOs refrigerant with refrigeration oil was solved, significantly improving the lubrication effect and the wear resistance of the refrigeration unit.
Patent Information
- Application Number
- CN202511547120.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-28
- Publication Date
- 2026-02-17
AI Technical Summary
When HFOs refrigerant mixes with refrigeration oil, the oil film strength is low, resulting in poor lubrication and affecting the lifespan of the refrigeration unit.
By replacing isooctanoic acid in the raw materials for synthetic esters with caprylic/capric acid, polyol esters are prepared, forming a mixture with greater oil film strength and significantly improved lubrication effect.
It improves the solubility, viscosity, and lubrication performance of refrigeration oil, reducing the diameter of four-ball wear scars from over 1 mm to below 0.9 mm, with a minimum of 0.653 mm, thus extending the service life of the refrigeration unit.
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Figure FT_1
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of refrigerator oil, and particularly relates to a refrigerator oil for HFOs refrigerant, a working fluid composition and application. BACKGROUND
[0002] HFCs (hydrofluorocarbon) refrigerants are gradually eliminated due to long atmospheric residence time, high GWP and global climate warming caused by large use. Instead, natural working substances and HFOs (hydrofluoroolefin) refrigerants, i.e. HFOs refrigerants, will be used, which have low ODP and GWP. In terms of HFOs refrigerants, currently, large units using R1234ze (1,3,3,3-tetrafluoropropene) refrigerant are used to replace previously used R134a (1,1,1,2-tetrafluoroethane), and high-temperature heat pump units using R1233zd, R515B, etc.
[0003] However, replacing R1234ze refrigerant with the original R134a refrigerant still faces technical problems, especially in terms of refrigerator oil. HFOs, such as R1234ze, have a stronger dilution effect on the polyol isomeric acid ester refrigerator oil matched with R134a, so the viscosity of the mixture formed by the refrigerant and the refrigerator oil is lower under the same working condition, the oil film thickness is insufficient to withstand the working pressure, resulting in lubrication failure. The use of incompatible lubricating oil has lower lubricating performance, and changing the refrigerant will cause the service life of the refrigerator to be shortened.
[0004] Therefore, it is particularly important to propose a refrigerator oil for HFOs refrigerant, a working fluid composition and application that can maintain good oil film and excellent lubricating performance under working conditions while taking into account compatibility. SUMMARY
[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a refrigerator oil for HFOs refrigerant, a working fluid composition and application; the refrigerator oil for HFOs refrigerant can take into account compatibility, has a viscosity index of 110 or more, and the solubility viscosity of the refrigerator oil for HFOs refrigerant in R1234ze refrigerant is greater than 1.6 cP, and the lubricating performance is excellent.
[0006] The inventive concept of the present application is that: the prior product before the present technical solution still has the problem that the oil film strength after mixing with HFOs refrigerant is not high, resulting in poor lubricating effect of the refrigerator oil, but after replacing isooctanoic acid in the synthetic ester raw material with octyl decanoic acid, the oil film strength formed after mixing with the refrigerant is greatly improved, and the lubricating effect is significantly improved.
[0007] The first aspect of the present application provides a refrigerator oil for HFOs refrigerant.
[0008] Specifically, the refrigerant oil for HFOs refrigerant includes a polyol ester, and raw materials for preparing the polyol ester include a polyol, a first carboxylic acid, and a second carboxylic acid; the polyol includes at least one of dipentaerythritol, pentaerythritol, and trimethylolpropane; the first carboxylic acid includes octanecapric acid; and the second carboxylic acid includes at least one of isononyl acid, isooctanoic acid, and adipic acid.
[0009] Preferably, the octanecapric acid includes n-octanoic acid and n-decanoic acid, and a ratio between the n-octanoic acid and the n-decanoic acid is 1:0.5-1.5; further preferably, the ratio between the n-octanoic acid and the n-decanoic acid is 1:0.8-1.2.
[0010] Compared with the prior art, the first aspect provides the refrigerant oil for HFOs refrigerant with the following beneficial effects: when the HFOs refrigerant is mixed with the refrigerant oil to form a working fluid composition, the refrigerant oil can still maintain a good solubility viscosity, thereby maintaining lubrication and a good oil film thickness, and further improving wear resistance of the working fluid, and a four-ball wear scar diameter can be reduced from more than 1 mm of the original product to less than 0.9 mm, and a minimum four-ball wear scar diameter can reach 0.653 mm.
[0011] Preferably, the polyol includes at least one of dipentaerythritol and pentaerythritol, the first carboxylic acid includes octanecapric acid, and the second carboxylic acid includes at least one of isononyl acid and isooctanoic acid; or the polyol includes trimethylolpropane, the first carboxylic acid includes octanecapric acid, and the second carboxylic acid includes adipic acid.
[0012] Preferably, the polyol includes at least one of dipentaerythritol and pentaerythritol, the first carboxylic acid includes octanecapric acid, and the second carboxylic acid includes at least one of isononyl acid and isooctanoic acid.
[0013] Preferably, the polyol includes trimethylolpropane, the first carboxylic acid includes octanecapric acid, and the second carboxylic acid includes adipic acid.
[0014] Preferably, the first carboxylic acid and the second carboxylic acid include (1-12):1 in terms of a substance amount ratio; further preferably, the first carboxylic acid and the second carboxylic acid include (2-4):1 in terms of the substance amount ratio. Further limiting the first carboxylic acid and the second carboxylic acid to the substance amount ratio of (2-4):1 can further improve lubricating properties of the refrigerant oil, and a minimum four-ball wear scar diameter can be further reduced to less than 0.8 mm.
[0015] Preferably, a ratio between a total number of carboxylic acid groups of the first carboxylic acid and the second carboxylic acid and a total number of hydroxyl groups of the polyol is 1:(0.7-1).
[0016] Preferably, the HFOs refrigerant refrigeration oil further includes additives, including antioxidants, metal corrosion inhibitors, acid scavengers, anti-wear agents, and defoamers; the antioxidants include phenolic antioxidants, the metal corrosion inhibitors include benzotriazole, the acid scavengers include epoxy compounds, the anti-wear agents include at least one of phosphorus compounds and phosphorus-sulfur compounds, and the defoamers include dimethyl silicone oil.
[0017] Preferably, the antioxidant comprises di-tert-butyl-p-cresol.
[0018] Preferably, the antioxidant content accounts for 0.1 wt% to 0.5 wt% of the HFOs refrigerant refrigeration oil.
[0019] Preferably, the metal corrosion inhibitor comprises benzotriazole.
[0020] Preferably, the content of the metal corrosion inhibitor is 0.001 wt% to 0.01 wt% of the HFOs refrigerant refrigeration oil.
[0021] Preferably, the acid scavenger comprises glycidyl ester.
[0022] Preferably, the acid scavenger content is 0.1wt%-1.0wt% of the HFOs refrigerant refrigeration oil.
[0023] Preferably, the anti-wear agent comprises trimethylphenol phosphate.
[0024] Preferably, the anti-wear agent accounts for 0.1wt%-1.0wt% of the HFOs refrigerant refrigeration oil.
[0025] Preferably, the defoamer comprises dimethyl silicone oil.
[0026] Preferably, the defoamer accounts for 0.001wt%-0.1wt% of the HFOs refrigerant refrigeration oil.
[0027] Preferably, the HFOs refrigerant refrigeration oil further includes a metal deactivator, which includes benzotriazole and benzotriazole derivatives.
[0028] Preferably, the metal deactivator accounts for 0.001wt%-0.01wt% of the HFOs refrigerant refrigeration oil.
[0029] Preferably, the acid value of the refrigeration oil used as the HFOs refrigerant is less than or equal to 0.05 mg KOH / g.
[0030] Preferably, the kinematic viscosity of the HFOs refrigerant refrigeration oil at 40°C is 30-350 mmHg. 2 / s.
[0031] Preferably, the viscosity index of the HFOs refrigerant refrigeration oil is greater than or equal to 110 and less than or equal to 200.
[0032] Preferably, the moisture content of the refrigeration oil for HFOs refrigerant is less than 100 ppm, and more preferably, the moisture content of the refrigeration oil for HFOs refrigerant is less than 50 ppm.
[0033] Preferably, the method for preparing the polyol ester includes the following steps: (1) The polyol, the first carboxylic acid, and the second carboxylic acid are added to a reaction vessel and stirred to mix; (2) Heat to 230℃-250℃ and react for 10-12 hours to obtain crude product; (3) The crude product is distilled, washed with alkali and water, the organic phase is filtered and water is removed to obtain the polyol ester.
[0034] Preferably, in step (2), the hydroxyl value of the crude product is <10 mg KOH / g.
[0035] Preferably, the polyol ester has an acid value of less than or equal to 0.05 mg KOH / g and a kinematic viscosity of 30-350 mmHg at 40°C. 2 / s, viscosity index greater than or equal to 110 and less than or equal to 200, moisture content less than 50ppm.
[0036] Preferably, the method for producing the HFOs refrigerant refrigeration oil includes the following steps: mixing the polyol with the additive.
[0037] A second aspect of the present invention provides a working fluid composition.
[0038] A working fluid composition comprising any of the aforementioned refrigeration oils and hydrofluoroolefin (HFO) refrigerants.
[0039] Preferably, the hydrofluoroolefin refrigerant includes at least one of R1234ze (1,3,3,3-tetrafluoro-1-propene), R1233zd (1-chloro-3,3,3-trifluoropropene), and R515B; more preferably, the hydrofluoroolefin refrigerant includes R1234ze (1,3,3,3-tetrafluoro-1-propene). The R515B refrigerant comprises 85-90 wt% R1234ze and 10-15 wt% R227ea (heptafluoropropane).
[0040] A third aspect of the present invention provides the application of any of the HFOs refrigerant refrigeration oils described herein in an air conditioning system using hydrofluoroolefin (HFOs) refrigerants.
[0041] Preferably, the air conditioning system includes a dual-purpose cooling and heating system, and the compressor used includes a rotary compressor or a scroll compressor.
[0042] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) After replacing isooctanoic acid in the synthetic ester raw material with caprylic acid, the strength of the oil film formed after mixing with the refrigerant is greatly enhanced, and the lubrication effect is significantly improved. When HFOs refrigerant is mixed with refrigeration oil to form a working fluid composition, the refrigeration oil can still maintain a good solubility viscosity, thereby maintaining a good oil film thickness for lubrication, and thus improving the wear resistance of the working fluid. The diameter of the four-ball wear scar can be reduced from more than 1 mm in the original product to less than 0.9 mm, and the minimum diameter of the four-ball wear scar can reach 0.653 mm. Attached Figure Description
[0043] Figure 1 The infrared spectrum of the polyol ester prepared in Example 7 of this invention. Detailed Implementation
[0044] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.
[0045] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.
[0046] In the various embodiments and comparative examples of this invention, the ratio of octanoic acid to decanoic acid in caprylic / capric acid is 58:42, and the acid was purchased from Guangdong Feishun Chemical Co., Ltd.
[0047] The method for testing the solubility viscosity in this invention is as follows: 100g of refrigeration oil is added to a 250mL autoclave equipped with an online viscometer. The entire container is first devastated, and then 100mL of sufficient R1234ze (1,3,3,3-tetrafluoro-1-propylene) refrigerant is injected at low temperature to form a fluid mixture. The solubility viscosity is then measured at 80℃ and 2.3MPa.
[0048] The test method of the four-ball friction test in this invention is as follows: the test conditions are 75℃ temperature, 392N load, 1200rpm speed, and 1h running time. Different refrigeration oil samples are tested in a high-speed four-ball friction test. After the test, the wear scar diameter data of different oils are statistically compared.
[0049] The total types and amounts of additives in the refrigeration oil in the various embodiments and comparative examples of the present invention are as follows: 0.3 wt% antioxidant di-tert-butyl-p-cresol, 0.6 wt% acid scavenger glycidyl ester, 0.5 wt% anti-wear agent trimethylphenol phosphate, 0.002 wt% metal corrosion inhibitor benzotriazole, and 0.001 wt% defoamer dimethyl silicone oil.
[0050] The preparation steps of the HFOs refrigerant refrigeration oil in the various embodiments and comparative examples of the present invention are as follows: (1) Add the polyol, the first carboxylic acid, and the second carboxylic acid into the reaction vessel and stir and mix at 25°C; (2) The temperature was raised to 240℃ and the reaction was carried out for 12 hours to obtain the crude product; the hydroxyl value of the crude product was tested and found to be less than 10 mg KOH / g and in the range of 3-6 mg KOH / g. (3) The crude product was distilled at 200℃, and the distillation residue was washed with alkali and water at 95℃. The organic phase was filtered and water was removed to obtain polyol esters. The acid value of the obtained polyol esters was tested and found to be less than 0.05 mg KOH / g and in the range of 0.01-0.03 mg KOH / g. (4) The obtained polyol ester is mixed with additives to obtain HFOs refrigerant refrigeration oil.
[0051] Examples 1-4 HFOs refrigerant refrigeration oils are composed of polyol esters and additives. The raw materials for preparing polyol esters and the performance data of each refrigeration oil (kinematic viscosity at 40℃, viscosity index, and four-ball wear scar diameter) are recorded in Table 1.
[0052] Table 1. Raw materials and performance data of various refrigeration oils used in the preparation of polyol esters in Examples 1-4.
[0053] Example 1 Example 2 Example 3 Example 4 polyols Dipentaerythritol 0.12 mol Dipentaerythritol 0.12 mol Pentaerythritol 0.2 mol Pentaerythritol 0.2 mol First carboxylic acid Caprylic / capric acid 0.5 mol Caprylic / capric acid 0.8 mol Caprylic / capric acid 0.5 mol Caprylic / capric acid 0.6 mol Dicarboxylic acid 0.5 mol of valeric acid Isonononanoic acid 0.2 mol Isooctanoic acid 0.5 mol Isonononanoic acid 0.4 mol 40 °C kinematic viscosity (mm 2 / s) 57.23 116.34 32.81 63.48 Viscosity Index 141 127 116 113 Solution viscosity (cP) 1.563 1.926 1.378 1.614 Four-ball wear scar diameter (mm) 0.898 0.782 0.976 0.862 Examples 5-8 HFOs refrigerant refrigeration oils are composed of polyol esters and additives. The raw materials for preparing polyol esters and the performance data of each refrigeration oil (kinematic viscosity at 40℃, viscosity index, and four-ball wear scar diameter) are recorded in Table 2.
[0054] Figure 1 The image shows the infrared spectrum of the polyol ester prepared in Example 7.
[0055] Table 2. Raw materials and performance data of various refrigeration oils used in the preparation of polyol esters in Examples 5-7.
[0056] Example 5 Example 6 Example 7 polyols 0.25 mol of trimethylolpropane 0.25 mol of trimethylolpropane 0.25 mol of trimethylolpropane First carboxylic acid Caprylic / capric acid 0.923 mol Caprylic / capric acid 0.8 mol Caprylic / capric acid 0.667 mol Dicarboxylic acid Adipic acid 0.077 mol 0.2 mol adipic acid Adipic acid 0.333 mol 40 °C kinematic viscosity (mm 2 / s) 66.47 173.4 328.7 Viscosity Index 148 150 150 Solution viscosity (cP) 1.673 2.069 2.541 Four-ball wear scar diameter (mm) 0.847 0.726 0.653 Setting the molar ratio of the first carboxylic acid to the second carboxylic acid to (2-4):1 can further improve the lubrication performance of refrigeration oil, and the minimum four-ball wear scar diameter can be further reduced to below 0.8 mm.
[0057] Comparative Examples 1-5 Refrigeration oil is composed of polyol esters and additives. The raw materials for preparing polyol esters and the performance data of each refrigeration oil obtained are recorded in Table 3.
[0058] Table 3. Data on the raw materials and performance of various refrigeration oils used in the preparation of polyol esters for Comparative Examples 1-5.
[0059] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 polyols Dipentaerythritol 0.12 mol Pentaerythritol 0.2 mol Pentaerythritol 0.2 mol 0.25 mol of trimethylolpropane 0.25 mol of trimethylolpropane First carboxylic acid Isooctanoic acid 0.5 mol 0.6 mol of n-decanoic acid 0.6 mol of caprylic acid 0.667 mol of decanoic acid 0.667 mol of caprylic acid Second carboxylic acid Isonononanoic acid 0.5 mol Isonononanoic acid 0.4 mol Isonononanoic acid 0.4 mol Adipic acid 0.333 mol Adipic acid 0.333 mol 40 °C kinematic viscosity (mm 2 / s) 176.1 79.37 66.52 69.76 62.53 Viscosity Index 90 93 90 97 92 Solution viscosity (cP) 1.235 1.123 1.087 1.094 1.061 Four-ball wear scar diameter (mm) 1.087 1.182 1.213 1.204 1.236 Replacing isooctanoic acid in the synthetic ester raw materials with caprylic / capric acid significantly enhances the strength of the oil film formed when mixed with the refrigerant, resulting in a marked improvement in lubrication. Subsequent studies have found that caprylic / capric acid, compared to octanoic acid or capric acid alone, produces higher oil film strength in the synthetic esters of dipentaerythritol ester, pentaerythritol ester, and trihydroxypropane ester, and thus provides better lubrication for refrigeration oils.
[0060] The experimental data above show that, compared with the comparative example, the embodiment has a higher solubility viscosity, a smaller four-ball wear scar diameter, and stronger lubrication and wear resistance. The comparative example has poorer solubility viscosity and lubrication ability.
[0061] The refrigeration oil of the present invention still has a high viscosity when dissolved by HFOs, and also has excellent lubrication and wear resistance performance, making it suitable for refrigeration and heat pump operation of HFOs systems.
Claims
1. A refrigeration oil for HFOs refrigerant, characterized in that, The HFOs refrigerant refrigeration oil includes a polyol ester, and the raw materials for preparing the polyol ester include a polyol, a first carboxylic acid, and a second carboxylic acid; the polyol includes at least one of pentaerythritol, pentaerythritol, and trimethylolpropane, the first carboxylic acid includes caprylic acid, and the second carboxylic acid includes at least one of isononanoic acid, isooctanoic acid, and adipic acid.
2. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The caprylic / capric acid includes octanoic acid and capric acid, and the ratio between octanoic acid and capric acid is 1:0.5-1.
5.
3. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The polyol includes at least one of pentaerythritol and bispentaerythritol, the first carboxylic acid includes caprylic / decanoic acid, and the second carboxylic acid includes at least one of isononanoic acid and isooctanoic acid.
4. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The polyol includes trimethylolpropane, the first carboxylic acid includes caprylic / decanoic acid, and the second carboxylic acid includes adipic acid.
5. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The first carboxylic acid and the second carboxylic acid are in a molar ratio of (1-12):
1.
6. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The ratio of the sum of the number of carboxylic acid groups in the first carboxylic acid and the second carboxylic acid to the number of hydroxyl groups in the polyol is 1:(0.7-1).
7. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The HFOs refrigerant refrigeration oil also includes additives, including antioxidants, metal corrosion inhibitors, acid scavengers, anti-wear agents, and defoamers; the antioxidants include phenolic antioxidants, the metal corrosion inhibitors include benzotriazole, the acid scavengers include epoxy compounds, the anti-wear agents include at least one of phosphorus compounds and phosphorus-sulfur compounds, and the defoamers include dimethyl silicone oil.
8. The refrigeration oil for HFOs refrigerant according to claim 1, characterized in that, The method for preparing the polyol ester includes the following steps: (1) The polyol, the first carboxylic acid, and the second carboxylic acid are added to a reaction vessel and stirred to mix; (2) Heat to 230℃-250℃ and react for 10-12 hours to obtain crude product; (3) The crude product is distilled, washed with alkali and water, the organic phase is filtered and water is removed to obtain the polyol ester.
9. A working fluid composition, characterized in that, Includes HFOs refrigerant refrigeration oils as described in any one of claims 1-8 and hydrofluoroolefin refrigerants.
10. The application of the HFOs refrigerant refrigeration oil according to any one of claims 1-8 in an air conditioning system using hydrofluoroolefin refrigerants.