Additive, method for producing additive, lubricating oil containing additive, and method for producing lubricating oil containing additive

Abstract

To provide an additive capable of being produced at relatively low cost and effectively improving the sliding property of a movable member.SOLUTION: An additive according to one embodiment of the present disclosure is an additive to be added to lubricating oil, and has granules containing soluble silicic acid as a main component.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to additives and methods for making the additives. [Background technology]

[0002] Lubricating oils are sometimes used to allow parts to slide smoothly against each other. Some lubricating oils, such as grease, have a relatively high viscosity and are applied to the outer surfaces of moving parts, such as cylinder rods, to reduce sliding resistance. Others, such as engine oil, have a relatively low viscosity and are injected into an apparatus (engine) to flow and reduce the sliding resistance of the moving parts within the apparatus. Additives may be added to such lubricating oils to improve lubricity (see JP 2018-053021 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-053021 Summary of the Invention [Problem to be solved by the invention]

[0004] The engine oil additive of Patent Document 1 achieves low friction by including specific components such as nano-onion-like carbon. Because nano-onion-like carbon is relatively expensive to manufacture, it may be difficult to provide the additive at a low cost. From the perspective of protecting the global environment, improving fuel economy by improving the sliding properties of engine oil is desirable, and there is a demand for additives that are cheaper and easier to use. Furthermore, for greases and the like that are applied directly to the outer surfaces of moving parts, there is a demand for additives that can easily improve sliding properties at a low cost, in order to improve the operating efficiency of equipment that uses those moving parts.

[0005] In view of the above circumstances, an object of the present disclosure is to provide an additive that can be produced at a relatively low cost and that can effectively improve the sliding properties of movable members. [Means for solving the problem]

[0006] An additive according to one embodiment of the present disclosure that solves the above problems is an additive to be added to a lubricating oil, and has granules whose main component is soluble silicic acid. [Effects of the Invention]

[0007] The additive of the present disclosure can be produced at a relatively low cost and can effectively improve the sliding properties of movable parts. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0009] (1) An additive according to one embodiment of the present disclosure is an additive to be added to a lubricating oil, and has granules containing soluble silicic acid as a main component.

[0010] Since this additive has granules whose main component is soluble silicic acid, it can improve the lubricity (sliding properties of components) of the lubricating oil to which the additive is added, effectively reducing friction. Furthermore, since soluble silicic acid is abundant in nature, it is easily available and can be produced at low cost. The term "main component" refers to the component whose content ratio is the largest among all components, for example, a component that is 50% by mass or more.

[0011] (2) In the above (1), the granules may further contain potassium oxide, which can further improve the lubricity.

[0012] (3) In the above (1) or (2), the granules may further contain calcium oxide, which can further improve the lubricity.

[0013] (4) In any of (1) to (3), the granules may have an average particle size of 12 μm or less. By having the granules have an average particle size of 12 μm or less, the lubricity can be improved more easily. The average particle size refers to the 50% cumulative volume standard (D50 value) measured using a laser scattering particle size distribution analyzer.

[0014] (5) An additive according to one embodiment of the present disclosure is an additive to be added to a lubricating oil, and includes a calcined product obtained by calcining a plant shell.

[0015] Since many plant shells contain silicon, a fired product containing soluble silicic acid can be easily obtained by firing the plant shells. The additive contains a fired product obtained by firing the plant shells, and therefore can effectively improve the lubricity. Since the plant shells are easily available, the additive can be produced at low cost.

[0016] (6) A method for producing an additive according to one embodiment of the present disclosure is a method for producing an additive to be added to a lubricating oil, and includes the steps of calcining plant shells and pulverizing the calcined shells.

[0017] Since many plant shells contain silicon, calcination can easily produce a calcined product containing soluble silicic acid. By pulverizing this calcined product, the shape (particle size) can be made uniform. Therefore, this additive manufacturing method can produce an additive that can effectively improve the lubricity of lubricating oils at low cost.

[0018] (7) In the above (6), the husk may be rice husk, which has a high silicon content, making it easy to obtain a burned product containing a sufficient amount of soluble silicic acid.

[0019] [Details of the Mode for Carrying Out the Disclosure] An example of an embodiment of the present disclosure will be described in detail below.

[0020] <Additives> The additive is an additive to be added to a lubricating oil, and has granules whose main component is soluble silica. The lubricating oil is not particularly limited as long as it forms a film between a moving part and a non-moving part on which the moving part is disposed or another moving part to improve sliding properties. For example, it may be engine oil used in the internal combustion engine of a transportation device such as an automobile, or transmission oil used in a transmission, or grease applied to the outer surface of a sliding part or enclosed in the seal of a sealed bearing.

[0021] The additives may be added after the lubricating oil has been produced or during the production of the lubricating oil, i.e., the additives may be added to the lubricating oil before use, or the lubricating oil to which the additives have been added may be prepared and used.

[0022] The lower limit of the ratio of the content of soluble silicic acid contained in the granules is preferably 50% by mass. The lower limit of the ratio may be 55% by mass, 60% by mass, or 70% by mass. The upper limit of the ratio is not particularly limited and may be 100% by mass or 99% by mass. When the granules contain soluble silicic acid in the above range, the lubricity of the lubricating oil containing the additive can be improved.

[0023] The reason why adding an additive containing soluble silica to a lubricating oil improves lubricity is unclear, but it is thought that the granular material is crushed when the components slide, filling in and flattening the surface roughness (unevenness) of the sliding surface, thereby improving lubricity (slidability). It is also thought that the inclusion of soluble silica makes the lubricant more likely to have a porous structure, which retains the lubricating oil and promotes the thickening effect of the lubricating oil. It is also thought that the soluble silica is absorbed into the lubricating oil as silicon ions, causing a chemical reaction in the lubricating oil and improving the fluidity of the lubricating oil.

[0024] The lower limit of the ratio of silicon element content to all elements of the granular material determined by quantitative analysis using a fluorescent X-ray analyzer may be 60 mass%, 70 mass%, 80 mass%, or 85 mass%, and the upper limit of the ratio is not particularly limited and may be 99 mass%.

[0025] The raw material for the granules is not particularly limited as long as it contains soluble silicic acid, but it is preferable to use waste materials, such as combustion ash from thermal power plants, slag from steel mills, and dust ash, or burned plants, and particularly burned plant shells. That is, in another embodiment, the additive may contain a burned product of burned plant shells. The plant shell is not particularly limited, but rice husks, which have a high silicon content, are preferred.

[0026] The lower limit of the temperature for firing the plant shells is preferably 200° C., more preferably 300° C. The upper limit of the temperature is not particularly limited and may be 1000° C., 800° C., or 600° C. By setting the temperature for firing the plant shells within the above range, the ease of obtaining soluble silicic acid can be improved.

[0027] The granules may further contain potassium oxide (KO). The addition of potassium oxide in the additive can further improve the lubricity of the lubricating oil. The upper limit of the potassium oxide content in the additive may be 5.0 mass%, 4.0 mass%, or 3.5 mass%.

[0028] The granules may further contain calcium oxide (CaO). The inclusion of calcium oxide in the additive further improves the lubricity of the lubricating oil. The upper limit of the calcium oxide content in the additive may be 2.5 mass%, 2.0 mass%, or 1.5 mass%.

[0029] The granular material may contain other components such as diphosphorus pentoxide (P2O5), manganese monoxide (MnO), magnesium oxide (MgO), iron oxide (Fe2O3), sulfur trioxide (SO3), and aluminum oxide (Al2O3). The upper limit of the ratio of each content is preferably 0.5 mass% for diphosphorus pentoxide, 0.5 mass% for manganese monoxide, 0.3 mass% for magnesium oxide, 0.2 mass% for iron oxide, 0.3 mass% for sulfur trioxide, and 0.15 mass% for aluminum oxide.

[0030] The average particle size of the granules is preferably 12 μm or less. The upper limit of the average particle size of the granules may be 10.0 μm or 8.0 μm. The lower limit of the average particle size is not particularly limited and may be 0.5 μm or 1.0 μm. By setting the average particle size within the above range, the dispersibility of the granules in the lubricating oil is improved, and the lubricity of the lubricating oil can be improved.

[0031] The additive may further contain talc granules. That is, the additive may contain granules (first granules) mainly composed of soluble silicic acid and talc granules (second granules). Talc is a soft mineral, and it is believed that the addition of talc to the additive more effectively fills in and smooths the surface roughness of the sliding surface, thereby improving the lubricity.

[0032] The upper limit of the talc content ratio in the additive may be 70% by mass or 60% by mass. The lower limit of the talc content ratio is not particularly limited and may be 10% by mass, 20% by mass, 30% by mass, or 40% by mass. The additive may have the first granules and the second granules in a mass ratio of 1:1.

[0033] The upper limit of the average particle size of the talc may be 12.0 μm, 10.0 μm, or 8.0 μm. The lower limit of the average particle size is not particularly limited and may be 0.5 μm or 1.0 μm. The average particle size of the talc (second granules) is preferably approximately the same as that of the first granules. By setting the average particle size within the above range, the dispersibility of the talc (second granules) in the lubricating oil can be made equivalent to that of the first granules, thereby improving the lubricity.

[0034] The amount of the additive to be added to the lubricating oil is not particularly limited and may be determined as appropriate depending on the properties, conditions of use, and purpose of the lubricating oil. Specifically, for example, the lower limit of the amount of the additive to be added to 1.0 L of lubricating oil may be 0.1 g, 0.2 g, or 0.3 g. The upper limit of the amount of the additive to be added to 1.0 L of lubricating oil is not particularly limited and may be 3.0 g, 2.0 g, or 1.5 g.

[0035] <Additive manufacturing method> The method for producing the additive includes the steps of burning plant shells and pulverizing the burned shells.

[0036] Since the shells of the above plants used in the firing step often contain silicon, firing can easily produce a fired product containing soluble silicic acid. The plant shells are preferably rice husks, which have a high silicon content. The firing method is not particularly limited, and a known firing furnace or the like may be used.

[0037] The means for pulverizing the burned shells (burned product) is not particularly limited, and may be a known grind mill, rotary cutter, etc. In the pulverizing step, it is preferable to mix talc with the burned plant shells and pulverize them together.

[0038] [Other embodiments] The above-described embodiments do not limit the configuration of the present invention. Therefore, the above-described embodiments may include omissions, substitutions, or additions of components based on the description in this specification and common general technical knowledge, and all of these should be construed as belonging to the scope of the present invention.

[0039] The potassium oxide, calcium oxide, other components, and talc are not essential components of the additive. That is, the content of potassium oxide, calcium oxide, and other components in the granules may be 0% by mass, and the content of talc in the additive may also be 0% by mass. Furthermore, the additive may contain inevitable impurities in addition to the above-mentioned components. The ratio of the total content of the inevitable impurities to the total content of the inevitable impurities is preferably less than 1% by mass. [Example]

[0040] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to these examples.

[0041] Rice husks were burned to obtain a burned product. The soluble silica content of this burned product was measured using Fertilizer Testing Methods (2023) 4.4.1.b-2017, and was found to be 56.7% by mass. A portion of the burned product was taken and divided into two parts (Test Example 1 and Test Example 2), and the contained elements and their contents were analyzed using an X-ray fluorescence analyzer. The results are shown in Table 1.

[0042] [Table 1]

[0043] Furthermore, the compositions and contents of Test Examples 1 and 2 were investigated. The results are shown in Table 2. In the table, "-" means that the measurement was not possible.

[0044] [Table 2]

[0045] The remainder of the calcined material was placed in a grinding mill, and the same mass of talc was added and pulverized to an average particle size of 120 μm or less. The pulverized calcined material and talc were added as additives to the engine oil of test vehicle 1 and test vehicle 2. The amount of additive added was 15.8 g for test vehicle 1 and 9.0 g for test vehicle 2. The fuel consumption rate (fuel economy) was calculated for two weeks before and two weeks after adding the additive. The results are shown in Table 3. Test vehicle 1: Route bus, diesel engine, 5190cc displacement Test vehicle 2: Microbus gasoline engine, 2693cc displacement

[0046] [Table 3]

[0047] Table 3 shows that adding the above additives to the engine oil improved fuel economy by 13.9% for test vehicle 1 and 15.2% for test vehicle 2. Drivers took turns driving, with four drivers driving test vehicle 1 and five for test vehicle 2, but there was no change in the strength of the engine brake. No changes were noticed in engine noise or vibration for test vehicle 1, but it was reported that engine noise and vibration had been reduced for test vehicle 2. This is thought to be because test vehicle 2 has its engine mounted at the front of the vehicle (below the driver), making it easy to detect changes in engine noise and vibration, whereas test vehicle 1 has its engine mounted at the rear of the vehicle, making it difficult to detect changes in engine noise and vibration.

[0048] In another test, when the additive was added to the engine oil of small heavy machinery (such as a bulldozer) where the driver (operator) is located close to the engine, no improvement in fuel economy was confirmed, but a clear reduction in engine noise and vibration was confirmed.With the cooperation of several people, the additive was added to the engine oil of private passenger cars (four-wheeled vehicles), and it was confirmed that in all cases, a fuel economy improvement of 10% or more and a reduction in engine noise and vibration were achieved. [Industrial Applicability]

[0049] The additive of the present disclosure can improve the lubricity of lubricating oils, and is therefore suitable for use in equipment, devices, etc. that use lubricating oils.

Claims

1. An additive to be added to a lubricating oil, An additive having granular material whose main component is soluble silicic acid.

2. 10. The additive of claim 1, wherein the granules further comprise potassium oxide.

3. 10. The additive of claim 1, wherein the granules further comprise calcium oxide.

4. 2. The additive according to claim 1, wherein the average particle size of the granules is 12 μm or less.

5. 5. The additive of claims 1 to 4, further comprising talc granules.

6. An additive to be added to a lubricating oil, An additive containing fired plant shells.

7. 1. A method for producing an additive for addition to a lubricating oil, comprising: Calcining the plant shells; crushing the fired shells; A method for producing an additive comprising:

8. The method for producing an additive according to claim 7, wherein the husk is rice husk.

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