Method for judging precipitation risk of lubricating oil and application

Abstract

The invention relates to the technical field of lubricating oil analysis, in particular to a method for judging the precipitation risk of lubricating oil and application. The method comprises the following steps: adding 0.08-1% by mass of water into lubricating oil, heating to 55-65 DEG C at the rotating speed of 550-650r / min, stirring for 8-13 minutes, keeping at 60-80 DEG C, and observing whether floccules appear or not; the lubricating oil comprises a clearing agent, and the clearing agent comprises sulfonate. The method is helpful for rapidly observing the precipitation risk of the lubricating oil, can reduce the time cost of investigation, and is easy to operate.

Description

Technical Field

[0001] The present invention relates to the technical field of lubricating oil analysis, and in particular to a method for judging the risk of lubricating oil precipitation and its application. Background Art

[0002] Detergents play an important role in lubricating oils. Currently, the most commonly used detergents are sulfonates, sulfurized alkylphenols, alkyl salicylates, thiophosphates and cyclopentaneates. Among them, sulfonate detergents have the advantages of good high-temperature detergency, strong neutralization ability, good rust prevention, certain dispersibility, easy availability of raw materials, and low price, and are widely used in lubricating oils.

[0003] For example, in the first half of 2016, most of the CK-4 specification products approved by the API lubricant department were sulfonate systems. In order to achieve a higher base number, a large amount of additives were added. In order to avoid the appearance of slightly turbid or a small amount of precipitation after a period of storage, the product development process often uses methods such as standing for 3-9 months to examine its precipitation trend or tendency. However, this method is currently time-consuming and time-consuming, resulting in a long development time and limitations in the test results. Summary of the invention

[0004] The present invention provides a method for judging the risk of lubricating oil precipitation and its application, so as to solve the defect that it takes a long time to examine the risk of lubricating oil precipitation in the prior art.

[0005] Among the lubricating oil components, detergents, i.e., sulfonates, are at risk of precipitation or precipitation. Sulfonate detergents contained in oil solutions for a short period of time can maintain good colloidal and micellar stability, but the structural characteristics of high-base sulfonates will inevitably cause micelle instability over time. The carbonate component in the detergent is dispersed in the oil by the soap component. When examining its storage stability in the laboratory, there are few disturbance factors, and it is difficult to simulate the disturbance factors and thermodynamic changes in actual conditions. The inventors found that when examining its precipitation trend, artificially adding small molecule interference factors (i.e., water) and controlling the stirring conditions and maintaining it within a certain temperature range can better simulate the disturbance factors and thermodynamic changes in actual conditions.

[0006] The present invention provides a method for judging the precipitation risk of lubricating oil. The lubricating oil is added with 0.08% to 1% by mass of water, heated to 55-65°C at a rotation speed of 550-650r / min, stirred for 8-13 minutes, and then maintained at 60°C to 80°C to observe whether floccules appear.

[0007] Preferably, 0.08% to 0.5% by mass of water is added to the lubricating oil, heated to 58-62° C. at a rotation speed of 580-620 r / min, stirred for 8-12 minutes, and then maintained at 65° C. to 75° C.

[0008] More preferably, 0.08% to 0.2% by mass of water is added to the lubricating oil, heated to 58-62° C. at a rotation speed of 590-610 r / min, stirred for 8-12 minutes, and then maintained at 68° C. to 72° C.

[0009] The lubricating oil includes a detergent, and the detergent includes a sulfonate. When developing a lubricating oil formula, the above method can be used to quickly identify the risk of lubricating oil precipitation, shorten the development cycle, and shorten the inspection time.

[0010] Preferably, the lubricating oil is diesel engine oil, and more preferably CK-4 diesel engine oil. According to experiments, the method of the present invention can be used to determine the precipitation risk of various CK-4 diesel engine oils.

[0011] According to the method for judging the precipitation risk of lubricating oil, the lubricating oil is a high base number lubricating oil, and its detergent is a calcium alkylbenzene sulfonate detergent, and the high base number is greater than 12 mgKOH / g. The detergent is calcium sulfonate, which is composed of neutral calcium sulfonate (soap) and inorganic alkaline components in micelles, and has a higher neutralization ability due to its high content of inorganic alkaline components.

[0012] According to the method for determining the risk of lubricating oil precipitation, the water is deionized water.

[0013] And / or, add water and stir well.

[0014] Preferably, a vertical mixer is used to stir until uniform.

[0015] According to the method for determining the risk of lubricating oil precipitation, a mixture of lubricating oil and water is placed in a transparent closed container for observation.

[0016] Preferably, the transparent closed container is a sealable glass test tube.

[0017] Preferably, the transparent closed container has a flat bottom.

[0018] Preferably, the diameter of the transparent closed container is not less than 2 cm.

[0019] Preferably, the sample is placed in a flat-bottomed sealable glass test tube with a diameter of not less than 2 cm.

[0020] According to the method for determining the risk of lubricating oil precipitation, observe whether floccules appear in a light-proof environment.

[0021] Preferably, the temperature is maintained at 60°C to 80°C in a constant temperature forced air drying oven.

[0022] Preferably, the heat preservation adopts a constant temperature blast drying oven, the constant temperature fluctuation is ±1°C, and the temperature resolution is 0.1°C; the water adopts deionized water, and after adding, it is stirred with a vertical stirrer until it is uniform.

[0023] Preferably, the diesel engine oil in the method should be placed in a flat-bottomed sealable glass test tube with a diameter of not less than 2 cm, and placed in a constant temperature blast drying oven in an upright position.

[0024] Preferably, the glass test tube is placed upright in a constant temperature forced air drying oven at 60° C. to 80° C., and after being placed for one week, the bottom of the test tube is observed to see whether there is flocculent matter.

[0025] According to the method for determining the risk of lubricating oil precipitation, the amount of lubricating oil used is 20-100 mL.

[0026] Preferably, the amount of the lubricating oil is 50 mL.

[0027] Preferably, 20-100 mL of lubricating oil is added to 0.1% to 1% by mass of deionized water.

[0028] According to the method for determining the risk of lubricant oil sedimentation, if flocs appear within 7 days, it means that the lubricant oil has a sedimentation risk within 3 months of storage.

[0029] Or, if no flocs appear within 7 days, it means that there is no risk of sedimentation in the lubricant after 3 months of storage.

[0030] According to the method for determining the risk of lubricant oil precipitation, if floccules appear within 10 days, it means that the lubricant oil has a risk of precipitation within 6 months of storage;

[0031] Alternatively, if no flocs appear within 10 days, it means that there is no risk of sedimentation in the lubricant after 6 months of storage.

[0032] The method for judging the precipitation risk of lubricating oil is applied in simulating whether there is a risk of lubricating oil being stored at room temperature and away from light.

[0033] Preferably, a simulation is performed to determine whether there is a risk of storing the lubricant oil at room temperature and away from light for 3-6 months.

[0034] Beneficial effects of the present invention:

[0035] The present invention finds that by artificially adding a small amount of water, controlling the stirring conditions and keeping the temperature at 60°C to 80°C, the precipitation risk of lubricating oil stored at room temperature can be predicted in advance while ensuring the accuracy of the results. This method can reduce the time cost of the investigation and is easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are some embodiments of the present invention.

[0037] Figure 1 The original investigation plan was to store the engine oil at room temperature and away from light for 3 months.

[0038] Figure 2 The results of the 10-day study of the scheme of the present invention are shown in FIG.

[0039] Figure 3 Structure of calcium sulfonate detergent for CK-4 diesel engine oil. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] In order to further verify the method of precipitation risk of CK-4 diesel engine oil, the original precipitation tendency investigation scheme of a certain CK-4 diesel engine oil was compared and verified with the scheme of the present invention.

[0043] The detergent used in this embodiment is calcium sulfonate, and the base oil used is Sinopec base oil.

[0044] Sample preparation: Calculate the mass of raw materials required for 50 ml CK-4 diesel engine oil according to the formula ratio; weigh the raw materials and heat to 60°C and stir for 30 minutes.

[0045] Test method 1: Store the sample at room temperature and away from light for 6 months, and observe the bottom test tube at 3 months and 6 months. Figure 1 As shown by Figure 1 It can be seen that under this method, CK-4 diesel engine oil was stored for 3 months without precipitation risk, and a small amount of floccules appeared at the bottom after 6 months.

[0046] Test method 2: Add 0.1% by mass of deionized water to the sample, use a vertical stirrer, heat to 60°C and stir for 10 minutes at a speed of 600 rpm. Put it in a constant temperature blast drying oven at 70°C and keep it warm for 10 days. Check the results at 7 and 10 days. No flocs appeared at the bottom of the test tube at 7 days, but flocs appeared at the bottom of the test tube at 10 days. The inspection results on the 10th day are as follows: Figure 2 As shown in the figure, under this test method, there is no risk of precipitation when the lubricant is stored for 3 months, but there is a risk of precipitation when it is stored for 6 months.

[0047] It can be seen from the results of test method 1 and test method 2 that when investigating the same product, the scheme of the present invention can be used to simulate the deterioration investigation conditions for 10 days to investigate its precipitation risk in the longer term in the future. The present invention helps to quickly observe the risk of lubricant oil precipitation. This method can reduce the time cost of the investigation and is easy to operate.

[0048] During the product development process, the laboratory environment is stable, and there are few factors affecting diesel engine oil products. It is difficult to examine the risk of precipitation under conventional storage conditions for 3 months. The present invention utilizes the characteristics of diesel engine oil components, adds 0.1% to 1% water by mass to diesel engine oil, and uses 60°C to 80°C insulation for 7-10 days to quickly examine whether there is a risk of precipitation. The use of the present invention requires less investment and time cost, and has the advantages of easy promotion and easy implementation.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the risk of lubricating oil precipitation, characterized in that: Add 0.08% to 1% by mass of water to the lubricating oil, heat to 55-65°C at a speed of 550-650r / min, stir for 8-13 minutes, and then maintain at 60°C to 80°C to observe whether flocs appear; Preferably, the lubricating oil is added with 0.08% to 0.5% by mass of water, heated to 58-62°C at a speed of 580-620 r / min, stirred for 8-12 minutes, and then maintained at 65°C to 75°C; The lubricating oil includes a detergent, and the detergent includes a sulfonate.

2. The method for determining the risk of lubricating oil precipitation according to claim 1, characterized in that: The lubricating oil is a high base number lubricating oil, and its detergent is a calcium alkylbenzene sulfonate detergent, and the high base number is greater than 12 mgKOH / g.

3. The method for determining the risk of lubricating oil precipitation according to claim 1 or 2, characterized in that: The water is deionized water; And / or, add water and stir well.

4. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 3, characterized in that: Place the mixture of lubricating oil and water in a transparent closed container; Preferably, the transparent closed container is a sealable glass test tube; Preferably, the transparent closed container has a flat bottom; Preferably, the diameter of the transparent closed container is not less than 2 cm.

5. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 4, characterized in that: Observe whether floccules appear in a dark environment; Preferably, the temperature is maintained at 60°C to 80°C in a constant temperature forced air drying oven.

6. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 5, characterized in that: The amount of lubricating oil is 20-100mL; Preferably, the amount of the lubricating oil is 50 mL.

7. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 6, characterized in that: If floccules appear within 7 days, it means that there is a risk of sedimentation within 3 months of storage of the lubricant; Or, if no flocs appear within 7 days, it means that there is no risk of sedimentation in the lubricant after 3 months of storage.

8. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 8, characterized in that: If floccules appear within 10 days, it means that there is a risk of sedimentation within 6 months of storage of the lubricant; Alternatively, if no flocs appear within 10 days, it means that there is no risk of sedimentation in the lubricant after 6 months of storage.

9. Application of the method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 8 in simulating whether there is a risk of lubricating oil being stored at room temperature and away from light; Preferably, a simulation is performed to determine whether there is a risk of storing the lubricant oil at room temperature and away from light for 3-6 months.

10. The method for determining the risk of lubricating oil precipitation according to any one of claims 1 to 8, or the use according to claim 9, characterized in that: The lubricating oil is diesel engine oil; CK-4 diesel engine oil is preferred.

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