Refrigerator oil base oil, refrigerator oil, fluid composition, and refrigeration compressor

Abstract

The application provides a refrigeration machine oil base oil, a refrigeration machine oil, a fluid composition and a refrigeration compressor. The refrigeration machine oil base oil comprises a first polyol ester, which is obtained by esterification reaction of adipic acid and iso-octanoic acid with pentaerythritol and then removal of acid by a neutralizing agent. The refrigeration machine oil base oil has excellent rheological properties, refrigerant compatibility and friction performance, has a low acid value, reduces corrosion of compressor pump body parts, and one of raw materials of the first polyol ester of the refrigeration machine oil base oil is adipic acid, so that a polymerized long-chain structure is generated, and the friction performance of the lubricating oil is improved.

Description

Technical Field

[0001] This invention relates to the field of refrigeration oil products, and more specifically to a refrigeration oil base oil, refrigeration oil, fluid composition, and refrigeration compressor. Background Technology

[0002] It is well known that synthetic and natural ester-based lubricants used in refrigeration compressors are highly sensitive to acid value. The acid value of these lubricants can significantly shorten the life of refrigeration oil and increase the risk of compressor failure, such as component corrosion and copper plating. Chinese patent CN105330543A provides a lubricant, but the oil synthesized according to this method requires vacuum deacidification followed by alkaline neutralization to meet the acid value requirements. However, the alkaline washing process generates surface-active soaps, which act as emulsifiers in the system, forming oil-in-water emulsions or microemulsions in the aqueous phase. This results in a loss of base oil and reduced yield, while also introducing new impurities. Therefore, alkaline washing for acid removal is not ideal for ester-based base oils. If the alkaline washing step is skipped and the refrigeration oil is applied directly to the compressor, its high acid value will easily cause corrosion of the compressor pump body parts over long-term use, making it unsuitable for direct application to hermetic refrigeration compressors. The compressor pump body is susceptible to corrosion due to the high acid value of the refrigeration oil, and the compressor pump body's own corrosion resistance also affects its corrosion resistance. Therefore, further improvements and development are still needed. Summary of the Invention

[0003] To address the shortcomings of existing technologies and solve the aforementioned problems, a refrigeration oil base oil, a refrigeration oil, a fluid composition, and a refrigeration compressor are proposed, and the following technical solutions are provided:

[0004] A refrigeration oil base oil includes a first polyol ester, which is obtained by esterification of adipic acid, isooctanoic acid and pentaerythritol as raw materials, followed by acid removal with a neutralizing agent.

[0005] Furthermore, the adipic acid is 0.12-0.28 mol relative to 1 mole of pentaerythritol, and the isooctanoic acid is 3.44-3.76 mol relative to 1 mole of pentaerythritol.

[0006] Furthermore, the neutralizing agent is a glycidyl tert-carbonate neutralizing agent, and the amount of the glycidyl tert-carbonate neutralizing agent is 1-3% of the mass of the first polyol.

[0007] Furthermore, after the esterification reaction, the acid is first removed under vacuum and then removed with a neutralizing agent. After the acid is removed with the neutralizing agent, the first polyol ester is obtained by adsorption with an alkaline adsorbent.

[0008] Furthermore, the refrigeration oil base oil also includes a second polyol ester, which is obtained by esterification reaction of isononanoic acid and isooctanoic acid with pentaerythritol.

[0009] Furthermore, by mass percentage, the first polyol ester comprises 30-70%, and the second polyol ester comprises 70-30%.

[0010] In addition, the present invention also provides a refrigeration oil, which includes the above-mentioned refrigeration oil base oil.

[0011] Furthermore, the refrigeration oil also includes additives, which include one or more of antioxidants, corrosion inhibitors, defoamers, and metal deactivators.

[0012] In addition, the present invention also provides a fluid composition comprising the above-mentioned refrigeration oil and refrigerant, wherein the refrigeration oil accounts for 70-100% by mass and the refrigerant accounts for 0-30%.

[0013] In addition, the present invention also provides a refrigeration compressor, wherein the pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel, and the above-mentioned fluid composition is added to the pump body of the refrigeration compressor.

[0014] Due to the adoption of the above technical solutions, the beneficial technical effects of the present invention are as follows:

[0015] 1. The refrigeration oil base oil of the present invention has excellent rheological properties, refrigerant compatibility and tribological properties, and has a low acid value, which reduces corrosion to compressor pump parts;

[0016] 2. One of the raw materials for the first polyol ester of the refrigeration oil base oil of the present invention is adipic acid, which will produce a polymer long chain structure, thereby improving the friction performance of the lubricating oil; the raw materials for the second polyol ester include isooctanoic acid and isononanoic acid, both of which have branched structures and their ester group shielding effect is better, thus having better hydrolysis resistance, which can ensure the chemical stability of the refrigeration oil base oil and improve its corrosion resistance.

[0017] 3. This invention uses special compressor pump body materials, which are used in conjunction with the fluid composition to improve the overall corrosion resistance of the compressor pump body, enabling the compressor to operate normally in a relatively low acid value environment. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those skilled in the art without creative effort should all fall within the scope of protection of this application.

[0019] A refrigeration oil base oil includes a first polyol ester, which is obtained by esterification of adipic acid, isooctanoic acid and pentaerythritol as raw materials, followed by acid removal with a neutralizing agent.

[0020] The simultaneous addition of adipic acid and isooctanoic acid, both of which react with pentaerythritol, allows for better control of the properties of the refrigeration oil base. This is achieved by adjusting the ratio of adipic acid to isooctanoic acid to obtain a refrigeration oil base with superior overall performance. The ratio of adipic acid to pentaerythritol is 0.12-0.28 mol, and the ratio of isooctanoic acid to pentaerythritol is 3.44-3.76 mol. The molar ratio of isooctanoic acid to adipic acid ranges from 93:7 to 97:3, with a preferred ratio of 95:5. Adipic acid is a dicarboxylic acid; if only adipic acid is added, it reacts with pentaerythritol to form a network polymer structure, which is solid at room temperature. If only isooctanoic acid is added, its lubricating performance is poor. Therefore, the simultaneous addition of adipic acid and isooctanoic acid ensures good lubrication of the subsequently prepared refrigeration oil while preventing the formation of the network structure. Different amounts of adipic acid and isooctanoic acid will result in different properties in the refrigeration oil produced subsequently.

[0021] The preparation process of the first polyol ester includes four steps: esterification, vacuum deacidification, neutralizing agent deacidification, and adsorption. After esterification, vacuum deacidification is performed using a scraped-film molecular distillation technique at a system pressure of 50 Pa and a temperature of 150 °C. The neutralizing agent deacidification process involves adding 1-3% (by weight of the base oil) of glycidyl tert-carbonate as a neutralizing agent, heating to 185 °C, and stirring for 3 hours for adsorption. Glycidyl tert-carbonate, as a neutralizing agent, does not generate surface-active soaps. Soaps form oil-in-water emulsions or microemulsions in the aqueous phase, causing loss of the refrigeration oil base oil and introducing new impurities. Therefore, using glycidyl tert-carbonate as a neutralizing agent avoids the formation of soaps. After neutralizing agent deacidification, 5% (by weight of the refrigeration oil base oil) of alkaline clay adsorbent is added, heated to 95 °C, stirred for 5 hours for adsorption, and then filtered to obtain the first polyol ester.

[0022] The refrigeration oil base oil also includes a second polyol ester, which is obtained by esterification of isononanoic acid and isooctanoic acid with pentaerythritol. The first and second polyol esters are blended. The first polyol ester is synthesized with the participation of adipic acid, thus forming a long polymer chain structure, which improves the frictional performance of the refrigeration oil base oil. The participation of adipic acid increases the number of ester groups and the long polymer chain structure in the first polyol ester. The second polyol ester is synthesized with the participation of isooctanoic acid and isonononanoic acid, both of which have branched structures and superior ester group shielding effect, resulting in better hydrolysis resistance and ensuring the chemical stability of the oil.

[0023] The second polyol ester is obtained by esterification of isononanoic acid and isooctanoic acid with pentaerythritol, without the need for subsequent neutralization. Furthermore, isooctanoic acid is present in a molar ratio of 2 moles to 1 mole of pentaerythritol, and isononanoic acid is present in a molar ratio of 1:1 to 2 moles to 1 mole of pentaerythritol.

[0024] Preferably, the first polyol ester comprises 30-70%, and the second polyol ester comprises 70-30%. To further achieve the desired refrigeration oil properties, a refrigeration oil base oil with excellent overall performance can be obtained by adjusting the mass fractions of the first and second polyol esters. Experiments have shown that when the first polyol ester comprises 30-70% and the second polyol ester comprises 70-30%, the resulting refrigeration oil base oil has a viscosity of 66.51-69.87 mmHg at 40°C. 2 / s.

[0025] A refrigeration oil comprising the aforementioned refrigeration oil base oil. It also includes additives, said additives comprising one or more of antioxidants, corrosion inhibitors, defoamers, and metal deactivators.

[0026] Furthermore, by mass percentage, the amount of base oil in the refrigeration oil is 90-99.7%, antioxidant is 0.1-3%, corrosion inhibitor is 0.1-3%, defoamer is 0.05-2%, and metal deactivator is 0.05-2%.

[0027] The antioxidant is BHT, the corrosion inhibitor is glycidyl tert-carbonate, the defoamer is 14-520 antifoaming agent, and the metal deactivator is a thiadiazole derivative.

[0028] A fluid composition comprising the aforementioned refrigeration oil and refrigerant, wherein the refrigeration oil comprises 70-100% by mass, and the refrigerant comprises 0-30%. The refrigerant may also be a hydrocarbon-containing refrigerant. The refrigerant is preferably R290 propane refrigerant. The refrigerant can dissolve well with the refrigeration oil in the distributor both during air conditioning operation and shutdown. Therefore, when the refrigeration oil and R290 refrigerant are mixed at an oil content of 70-100 wt%, no stratification occurs at temperatures above -30°C. This ensures that the liquid R290 refrigerant can be fully mixed and absorbed with the refrigeration oil, while simultaneously ensuring excellent frictional performance alongside the excellent miscibility of the R290 propane refrigerant with the refrigeration oil.

[0029] In addition, a refrigeration compressor is provided, wherein the pump body of the refrigeration compressor is made of martensitic precipitation-hardening stainless steel, and the above-mentioned fluid composition is used during the operation of the refrigeration compressor. Specifically, the grade of martensitic precipitation-hardening stainless steel is: 0Cr17Ni4Cu4Nb, with an Ms point of approximately 150℃ and an Mf point below 30℃. Copper in the steel is dispersed in the matrix as extremely fine and dispersed ε phases. When treated with H900, σb = 1310MPa, σ0.2 = 1170MPa, δ5 = 10%, and ψ = 40%. This steel has good corrosion resistance, superior to that of general martensitic stainless steel and similar to that of general austenitic stainless steel. The composition is as follows:

[0030] Table 1 Chemical composition (mass fraction, %) of 0Cr17Ni4Cu4Nb(17-4PH) steel

[0031] C Si Mr Cr Ni Cu No P S ≤0.07 ≤1.00 ≤1.00 15.50-17.50 3.00-5.00 3.00-5.00 0.15-0.45 ≤0.035 ≤0.030

[0032] Example 1

[0033] (1) By mass percentage, the base oil of the refrigeration oil includes 100% of the first polyol ester.

[0034] The first polyol ester is prepared by esterification of adipic acid, isooctanoic acid, and pentaerythritol. After esterification, the mixture undergoes vacuum deacidification followed by neutralization. The final product is obtained by adsorption using an alkaline adsorbent. The adipic acid content is 0.2 mol / L relative to 1 mol of pentaerythritol, and the isooctanoic acid content is 3.6 mol / L relative to 1 mol of pentaerythritol. The preparation process of the first polyol ester is as follows: esterification → vacuum deacidification (using a scraped-film molecular distillation technique, system pressure 50 Pa, temperature 150 °C) → neutralization (adding 2% glycidyl tert-carbonate neutralizing agent by mass of the first polyol ester, heating to 185 °C and stirring for 3 hours) → adsorption (adding 5% alkaline clay adsorbent by mass of the first polyol ester, heating to 95 °C and stirring for 5 hours, then filtering).

[0035] (2) By mass percentage, the refrigeration oil consists of 95% of the refrigeration oil base oil in (1), 1% of the antioxidant BHT, 2% of the corrosion inhibitor glycidyl tert-carbonate, 1% of the 14-520 antifoaming agent, and 1% of the metal deactivator thiadiazole derivative.

[0036] (3) The fluid composition consists of 80% of the refrigeration oil in (2) and 20% of the R290 refrigerant by mass percentage.

[0037] The pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel, with the grade: 0Cr17Ni4Cu4Nb.

[0038] Example 2

[0039] (1) By mass percentage, the base oil of the refrigeration oil comprises 70% of the first polyol ester and 30% of the second polyol ester.

[0040] The first polyol ester is prepared by esterification of adipic acid, isooctanoic acid, and pentaerythritol. After esterification, the mixture undergoes vacuum deacidification followed by neutralization. The final product is obtained by adsorption using an alkaline adsorbent. The adipic acid content is 0.12 mol / L relative to 1 mol of pentaerythritol, and the isooctanoic acid content is 3.76 mol / L relative to 1 mol of pentaerythritol. The preparation process of the first polyol ester is as follows: esterification → vacuum deacidification (using a scraped-film molecular distillation technique, system pressure 50 Pa, temperature 150 °C) → neutralization (adding 3% glycidyl tert-carbonate neutralizing agent by mass of the first polyol ester, heating to 185 °C and stirring for 3 hours) → adsorption (adding 5% alkaline clay adsorbent by mass of the first polyol ester, heating to 95 °C and stirring for 5 hours, then filtering).

[0041] (2) By mass percentage, the refrigeration oil consists of 90% of the refrigeration oil base oil in (1), 3% of the antioxidant BHT, 3% of the corrosion inhibitor glycidyl tert-carbonate, 2% of the 14-520 antifoaming agent, and 2% of the metal deactivator thiadiazole derivative.

[0042] (3) The fluid composition consists of 80% of the refrigeration oil in (2) and 20% of the R290 refrigerant by mass percentage.

[0043] The pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel, with the grade: 0Cr17Ni4Cu4Nb.

[0044] Example 3

[0045] (1) By mass percentage, the base oil of the refrigeration oil comprises 50% of the first polyol ester and 50% of the second polyol ester.

[0046] The first polyol ester is prepared by esterification of adipic acid, isooctanoic acid, and pentaerythritol. After esterification, the mixture undergoes vacuum deacidification followed by neutralization. The final product is obtained by adsorption using an alkaline adsorbent. The adipic acid content is 0.2 mol / L relative to 1 mol of pentaerythritol, and the isooctanoic acid content is 3.6 mol / L relative to 1 mol of pentaerythritol. The preparation process of the first polyol ester is as follows: esterification → vacuum deacidification (using a scraped-film molecular distillation technique, system pressure 50 Pa, temperature 150 °C) → neutralization (adding 2% glycidyl tert-carbonate neutralizing agent by mass of the first polyol ester, heating to 185 °C and stirring for 3 hours) → adsorption (adding 5% alkaline clay adsorbent by mass of the first polyol ester, heating to 95 °C and stirring for 5 hours, then filtering).

[0047] (2) By mass percentage, the refrigeration oil consists of 98% of the refrigeration oil base oil in (1), 0.2% of the antioxidant BHT, 1% of the corrosion inhibitor glycidyl tert-carbonate, 0.3% of the 14-520 antifoaming agent, and 0.5% of the metal deactivator thiadiazole derivative.

[0048] (3) The fluid composition consists of 70% of the refrigeration oil in (2) and 30% of the R290 refrigerant by mass percentage.

[0049] The pump body of the refrigeration compressor is made of gray cast iron.

[0050] Example 4

[0051] (1) By mass percentage, the base oil of the refrigeration oil comprises 30% of the first polyol ester and 70% of the second polyol ester.

[0052] The first polyol ester is prepared by esterification of adipic acid, isooctanoic acid, and pentaerythritol. After esterification, the mixture undergoes vacuum deacidification followed by neutralization. The final product is obtained by adsorption using an alkaline adsorbent. The adipic acid content is 0.28 mol / L relative to 1 mol of pentaerythritol, and the isooctanoic acid content is 3.44 mol / L relative to 1 mol of pentaerythritol. The preparation process of the first polyol ester is as follows: esterification → vacuum deacidification (using a scraped-film molecular distillation technique, system pressure 50 Pa, temperature 150 °C) → neutralization (adding 1% glycidyl tert-carbonate neutralizing agent by mass of the first polyol ester, heating to 185 °C and stirring for 3 hours) → adsorption (adding 5% alkaline clay adsorbent by mass of the first polyol ester, heating to 95 °C and stirring for 5 hours, then filtering).

[0053] (2) By mass percentage, the refrigeration oil consists of 99.7% of the refrigeration oil base oil in (1), 0.1% of the antioxidant BHT, 0.1% of the corrosion inhibitor glycidyl tert-carbonate, 0.05% of the 14-520 antifoaming agent, and 0.05% of the metal deactivator thiadiazole derivative.

[0054] (3) The fluid composition consists of 100% of the refrigeration oil in (2) by mass percentage. The pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel with the grade: 0Cr17Ni4Cu4Nb.

[0055] Comparative Example 1

[0056] (1) By mass percentage, the base oil of the refrigeration oil includes 100% of the first polyol ester.

[0057] The first polyol ester was obtained by esterification of adipic acid, isooctanoic acid, and pentaerythritol. The adipic acid content was 0.2 mol per mole of pentaerythritol, and the isooctanoic acid content was 3.6 mol per mole of pentaerythritol. The first polyol ester was not neutralized.

[0058] (2) By mass percentage, the refrigeration oil consists of 95% of the refrigeration oil base oil in (1), 1% of the antioxidant BHT, 2% of the corrosion inhibitor glycidyl tert-carbonate, 1% of the 14-520 antifoaming agent, and 1% of the metal deactivator thiadiazole derivative.

[0059] (3) The fluid composition consists of 50% of the refrigeration oil in (2) and 50% of the R290 refrigerant by mass percentage.

[0060] The pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel, with the grade: 0Cr17Ni4Cu4Nb.

[0061] Comparative Example 2

[0062] (1) By mass percentage, the base oil of the refrigeration oil comprises 50% of the first polyol ester and 50% of the second polyol ester.

[0063] The first polyol ester is obtained by esterification of adipic acid and pentaerythritol. The adipic acid content is 4 moles per mole of pentaerythritol, and isooctanoic acid is not added.

[0064] (2) By mass percentage, the refrigeration oil consists of 98% of the refrigeration oil base oil in (1), 0.2% of the antioxidant BHT, 1% of the corrosion inhibitor glycidyl tert-carbonate, 0.3% of the 14-520 antifoaming agent, and 0.5% of the metal deactivator thiadiazole derivative.

[0065] (3) The fluid composition consists of 70% of the refrigeration oil in (2) and 30% of the R290 refrigerant by mass percentage.

[0066] The pump body of the refrigeration compressor is made of martensitic precipitation hardening stainless steel, with the grade: 0Cr17Ni4Cu4Nb.

[0067] Comparative Example 3

[0068] (1) By mass percentage, the base oil of the refrigeration oil comprises 50% of the first polyol ester and 50% of the second polyol ester.

[0069] The first polyol ester is obtained by esterification of isooctanoic acid and pentaerythritol. The isooctanoic acid is present in a ratio of 4 moles to 1 mole of pentaerythritol, and adipic acid is not added.

[0070] (2) By mass percentage, the refrigeration oil consists of 98% of the refrigeration oil base oil in (1), 0.2% of the antioxidant BHT, 1% of the corrosion inhibitor glycidyl tert-carbonate, 0.3% of the 14-520 antifoaming agent, and 0.5% of the metal deactivator thiadiazole derivative.

[0071] (3) The fluid composition consists of 70% of the refrigeration oil in (2) and 30% of the R290 refrigerant by mass percentage.

[0072] The pump body of the refrigeration compressor is made of gray cast iron.

[0073] Comparative Example 4

[0074] (1) By mass percentage, the base oil of the refrigeration oil includes 100% second polyol ester.

[0075] (2) By mass percentage, the refrigeration oil consists of 98% of the refrigeration oil base oil in (1), 0.2% of the antioxidant BHT, 1% of the corrosion inhibitor glycidyl tert-carbonate, 0.3% of the 14-520 antifoaming agent, and 0.5% of the metal deactivator thiadiazole derivative.

[0076] (3) The fluid composition consists of 70% of the refrigeration oil in (2) and 30% of the R290 refrigerant by mass percentage.

[0077] The pump body of the refrigeration compressor is made of gray cast iron.

[0078] 1. The refrigeration oils obtained in Examples 1-4 and Comparative Examples 1-4 were subjected to compatibility tests with the refrigerant. The refrigerant and refrigeration oil were mixed in a certain proportion and sealed in a glass pressure vessel. The vessel was placed in a constant temperature chamber, and the mixture was gradually cooled from room temperature. When it cooled to a certain temperature, the mixture began to separate into two phases from a single mixed solution. The temperature at which the two phases separated was recorded as the separation temperature of the two phases at that proportion. By measuring different mixing ratios, a separation temperature curve could be obtained. Here, the highest separation temperature point was recorded as the separation temperature of the oil and the refrigerant.

[0079] II. Hydrolytic stability tests were conducted on the refrigeration oils obtained in Examples 1-4 and Comparative Examples 1-4. This test method simulated certain actual operating conditions of the compressor. A certain amount of distilled water was added to the refrigeration oil and mixed evenly until the water content was 1000 ppm. 30 g of the above-mentioned water-containing refrigeration oil was added to an autoclave, and the metal of the pump body of the refrigeration compressor in each example or comparative example was sealed in. The air in the autoclave was evacuated using a vacuum pump, and then 15 g of R290 refrigerant was sealed in. The reaction was carried out at a constant temperature of 175°C for 168 h. The acid value (mg KOH / g) of the oil sample after the test was measured and calculated, and the appearance of the metal was observed to see if there were any changes.

[0080] 3. Viscosity tests were performed on the fluid compositions obtained in Examples 1-4 and Comparative Examples 1-4. 80g of refrigeration oil was added to a 200ml pressure-resistant container equipped with an online viscometer and densitometer. The container was then degassed under vacuum, and an appropriate amount of R290 refrigerant was added. The temperature was raised to 80°C, and after the pressure stabilized at 3.4MPa, the dynamic viscosity and density of the composition were measured, and the kinematic viscosity of the composition was calculated.

[0081] IV. The fluid compositions obtained in Examples 1-4 and Comparative Examples 1-4 were subjected to lubrication performance tests. Lubricity was evaluated using the Falex ring block test of the fluid compositions. Wear was assessed by the width of the wear track and the size of the wear volume on the block specimen; smaller wear track width and wear volume indicated better lubricity. Test standard: ASTM D2714; Test materials: steel block, cast iron ring; Test start temperature: 25°C; Test pressure: 0.8 MPa; Test time: 1 hour; Rotation speed: 800 rpm.

[0082] The experimental data from the tests conducted in Examples 1-4 and Comparative Examples 1-4 are shown in Table 2 below.

[0083] Table 2 shows the experimental data results of Examples 1-4 and Comparative Examples 1-4.

[0084]

[0085]

[0086] As shown in the table above, in terms of lubricity, the base viscosity of the refrigeration oil in all examples is similar, and the kinematic viscosity of the mixture after mixing with the refrigerant is also similar. However, in terms of wear track width, the higher the proportion of the first polyol ester, the lower the wear track width and the better the lubricity. In contrast, Comparative Examples 3 and 4, which do not contain adipic acid, have larger wear track widths and relatively poorer lubricity. In terms of chemical stability, the acid values ​​of the examples after neutralization treatment are relatively low, indicating good corrosion resistance to pump body parts. In Example 3, even with gray cast iron, the pump body material remains uncorroded. In the other examples using martensitic stainless steel, the metals are basically uncorroded and the acid values ​​are all low. In the comparative examples, without neutralization treatment, the pump body material corrodes when martensitic stainless steel or gray cast iron is used. However, in Comparative Example 1, the use of martensitic stainless steel produces only a few corrosion spots, while Comparative Examples 3 and 4, using gray cast iron, produce more corrosion spots. For Comparative Example 2, which does not contain isooctanoic acid, pentaerythritol reacts with adipic acid to produce a solid network polymer structure.

[0087] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A refrigeration compressor oil base oil characterized by comprising: The first polyol ester is obtained by esterification reaction of adipic acid and iso-octanoic acid with pentaerythritol, and then removing acid by using a neutralizing agent; The amount of adipic acid is 0.12-0.28 mol per 1 mol of pentaerythritol, and the amount of iso-octanoic acid is 3.44-3.76 mol per 1 mol of pentaerythritol; The neutralizing agent is glycidyl ester of versatic acid, and the amount of the neutralizing agent is 1-3% of the mass of the first polyol ester; The first polyol ester is obtained by removing acid under vacuum after esterification reaction, and then removing acid by using a neutralizing agent, and then adsorbing by using a basic adsorbent.

2. The refrigerant oil base oil according to claim 1, characterized by, The refrigeration compressor oil base oil further comprises a second polyol ester, which is obtained by esterification reaction of iso-nonyl acid and iso-octanoic acid with pentaerythritol.

3. The refrigerant oil base oil according to claim 2, characterized by, The first polyol ester accounts for 30-70% and the second polyol ester accounts for 70-30% by mass percentage.

4. A refrigeration oil characterized by, The refrigeration compressor oil base oil comprises the refrigeration compressor oil base oil according to any one of claims 1-3.

5. The refrigerant oil according to claim 4, characterized by The refrigeration compressor oil base oil further comprises an additive, which comprises one or more of an antioxidant, an anticorrosive agent, a defoaming agent, and a metal deactivator.

6. A fluid composition characterized in that, The refrigeration compressor oil further comprises a refrigerant, and the refrigeration compressor oil accounts for 70-100% and the refrigerant accounts for 0-30% by mass percentage.

7. A refrigeration compressor, characterized by The pump body of the refrigeration compressor is made of martensite precipitation hardening stainless steel, and the pump body is filled with the fluid composition according to claim 6.

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