JP5820283B2 - Solid lubricating composition and lubricant composition using the same - Google Patents

Description

  The present invention relates to a solid lubricating composition used for sliding parts of various transport machines including automobiles, construction machines, machine tools, and a lubricant composition such as a lubricating oil containing such a solid lubricating composition. It is about things.

Lubricants such as lubricating oil and grease are applied to sliding parts such as bearing surfaces and guide surfaces in various mechanical devices in order to reduce frictional resistance and wear.
Recently, in order to cope with global environmental problems such as global warming, there has been an increasing demand for improving the fuel efficiency of automobiles for the purpose of reducing carbon dioxide emissions, improving the efficiency of engines and power transmission mechanisms. There is a need to develop possible lubricants.

  For example, Patent Document 1 proposes a lubricant composition in which diamond particle clusters, which are aggregates of diamond particles coated with amorphous carbon, are finely dispersed in a lubricant.

JP 2002-265968 A

However, the lubricating performance of the above-mentioned lubricant composition is not always sufficient, and since the diamond particle cluster content is large and the surface thereof is coated with amorphous carbon, an increase in cost can be avoided. There was no problem.
The present invention has been made in view of the above-described problems in conventional lubrication techniques and lubricants, and the object of the present invention is to exhibit extremely excellent friction reduction characteristics, for example, engine oil for automobiles. Another object of the present invention is to provide a solid lubricating composition that exhibits a significant improvement in fuel efficiency when applied to a transmission oil and a lubricant composition including the same.

As a result of intensive studies to achieve the above-mentioned object, the present inventors have, for example, a fluorine-based solid lubricant such as polytetrafluoroethylene (PTFE) and a hexagonal solid such as tungsten disulfide (WS ₂ ). The inventors have found that the above object can be achieved by using a mixture of a lubricant and hard particles such as nanodiamonds, and have completed the present invention.

The present invention is based on the above findings, and the solid lubricating composition of the present invention comprises a fluorine-based solid lubricant having an average particle size of 0.1 to 6 μm and a hexagonal solid lubricant having an average particle size of 0.1 to 6 μm. It is characterized by comprising a material and nanodiamond having an average particle size of 0.02 to 0.1 μm.

The lubricant composition of the present invention is characterized by containing the above-described solid lubricant composition of the present invention. The lubricant of the present invention contains the above-mentioned solid lubricant composition of the present invention in 1 L of base oil. It contains in the ratio of 0.5-30g.
And the lubricating additive of this invention contains the said solid lubricating composition of this invention in the ratio of 15-1000g in 1L of base oil, It is characterized by the above-mentioned.

  According to the present invention, the particles composed of the fluorine-based solid lubricant, the hexagonal solid lubricant, and the hard particles are used as the solid lubricant composition, so that the particles are applied as they are or as various lubricant compositions to the sliding parts of various mechanical devices. By doing so, extremely excellent friction reducing performance is exhibited, and a significant energy saving effect is obtained.

  Hereinafter, the solid lubricating composition of the present invention will be described more specifically and in detail together with embodiments thereof. In the present specification, “%” means mass percentage unless otherwise specified.

  As described above, the solid lubricating composition of the present invention comprises a fluorine-based solid lubricant having an average particle size of 0.1 to 6 μm, a hexagonal solid lubricant having an average particle size of 0.1 to 6 μm, and an average particle size of 0. 0.02 to 0.5 μm hard particles.

  Here, specific examples of the fluorine-based solid lubricant include, for example, polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and perfluoroalkoxy. Fluorine resin, tetrafluoroethylene-hexafluoropropylene copolymer, ethylene / tetrafluoroethylene copolymer, ethylene / chlorotrifluoroethylene copolymer solid and the like can be mentioned.

These fluorine-based solid lubricants can be used alone or as a mixture of two or more of them. Among these, polytetrafluorocarbons are preferred from the viewpoint of market price and availability. Ethylene can be preferably used.
In addition, as above-mentioned, it is necessary to use a 0.1-6 micrometer thing as an average particle diameter of the said fluorine-type solid lubricant, However, It is more desirable to exist in the range of 0.1-2 micrometers. This is because if it is less than 0.1 μm, it is difficult to produce, and if it exceeds 6 μm, the lubricating effect becomes low.

  Moreover, as content (mass%) of the said fluorine-type solid lubricant in the solid lubricating composition of this invention, it is desirable that it is 9 to 90%. This is because when the content of the fluorine-based solid lubricant is out of this range, there is a problem that the lubricating effect is lowered.

Examples of the hexagonal solid lubricant include graphite, boron nitride (BN), molybdenum disulfide (MoS ₂ ), tungsten disulfide (WS ₂ ), and tin disulfide (SnS ₂ ).
These can be used alone or in admixture of two or more. Among these, it is desirable to use molybdenum disulfide or tungsten disulfide alone or in combination. It is particularly desirable to use tungsten disulfide alone or mixed with molybdenum disulfide.

  The average particle size of these hexagonal solid lubricants is difficult to produce if it is less than 0.1 μm, and if it exceeds 6 μm, the lubrication effect is reduced, so that it is necessary to use one having a particle size of 0.1 to 6 μm as described above. However, it is more preferable to use the thing in the range of 0.1-2 micrometers.

  The content of the hexagonal solid lubricant in the solid lubricating composition of the present invention is preferably 9 to 90%. This is because if the content of the hexagonal solid lubricant is out of this range, the lubricating effect tends to be low.

Specific examples of the hard particles include oxide particles such as alumina (Al ₂ O ₃ ) and silica (SiO ₂ ), and ceramic particles such as silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ). Further, metal particles such as tungsten (W) and silicon (Si), and carbon-based particles such as nano diamond, carbon fullerene, carbon nanotube, and graphene can be used. Among these, nano diamond is preferably used. These hard particles can also be used alone or in combination of two or more.

  And as an average particle diameter of these hard particles, if less than 0.02 μm, it is difficult to produce, and if it exceeds 0.5 μm, the lubrication effect becomes low. Although it is necessary, it is more desirable to be in the range of 0.02 to 0.1 μm.

  The content of the hard particles in the solid lubricating composition of the present invention is preferably 0.1 to 9%. That is, if the content of these hard particles is out of this range, there is a possibility that a problem that the lubricating effect is lowered may occur.

  The nanodiamond used in the present invention does not need to be a special nanodiameter as long as the particle diameter is 0.02 to 0.5 μm as described above, regardless of the production method such as high-pressure synthesis method and vapor phase synthesis method. Can be used.

  Further, the proportions of the fluorine-based solid lubricant, the hexagonal solid lubricant and the hard particles in the solid lubricant composition of the present invention are 9 to 90%, 9 to 90% and 0.1, respectively, in mass ratio. It is desirable to be -9%.

The solid lubricating composition of the present invention can be used in the form of mixed particles composed of three components of a fluorine-based solid lubricant, a hexagonal solid lubricant, and hard particles, that is, in the form of powder. It can be used as a lubricant composition by mixing with a dispersion medium such as oil.
For example, it can be used as a lubricating oil by mixing with a base oil. At this time, if the base oil is solidified with a thickener, it can be used as a grease.

When the solid lubricating composition of the present invention is used as a lubricating oil, it is desirable to add the solid lubricating composition in a ratio of 0.5 to 30 g with respect to 1 L of base oil.
The base oil of such a lubricating oil is not particularly limited as long as it is normally used as a base oil of a lubricating oil composition, such as mineral oil, synthetic oil, fats and oils, and mixtures thereof. it can. In addition, these can be used alone or in a mixture of two or more.

Mineral oil is a refined petroleum oil fraction, and paraffinic or naphthenic oils, normal paraffins, and the like can be used.
On the other hand, as synthetic oil, for example, poly-α-olefin, poly-α-olefin hydride, isobutene oligomer, hydride of isobutene oligomer, isoparaffin, alkylbenzene, alkylnaphthalene, diester, polyol ester, polybutene, polyoxyalkylene Examples include glycol, dialkyl diphenyl ether, polyphenyl ether, and the like. In these, it is preferable to use poly- (alpha) -olefin and its hydride.

  Lubricants also contain various additives such as antioxidants, corrosion inhibitors, rust inhibitors, extreme pressure agents, detergent dispersants, viscosity index improvers, pour point depressants, antiwear agents, antifoaming agents. Etc. can be added as needed.

These additives are not particularly limited, and those conventionally used can be widely applied.
For example, examples of the corrosion inhibitor include benzotriazole and derivatives thereof, and zinc dithiophosphate, and examples of the rust inhibitor include carboxylic acid, phosphate, alcohol, sulfonate, and ester.

  Examples of extreme pressure agents include organic sulfur, phosphorus compounds, and organic halogen compounds. Examples of detergents include barium sulfonate, calcium sulfonate, magnesium phenate, calcium salicylate, and magnesium salicylate. Succinimide, succinic acid ester, benzylamine and the like.

  Examples of viscosity index improvers include polymethacrylates, olefin copolymers, styrene olefin copolymers, and polyisobutylene. Pour point depressants include alkylated aromatic compounds, alkylated aromatic compounds, ethylene / vinyl acetate copolymers, poly Examples include methacrylate.

  Examples of the antiwear agent include phosphoric acid ester and zinc dithiophosphate, and examples of the antifoaming agent include polymethyldioxane, metal soap, fatty acid ester, phosphoric acid ester, and polyalkylene glycol.

  The solid lubricating composition of the present invention can also be added to existing lubricants such as engine oil, gear oil, transmission oil, and machine oil. In this case, although depending on other additives, it is desirable to mix so that it may become the said ratio in general.

  In addition, when adding to such an existing lubricant, it is possible to add the solid lubricating composition in the form of powder, but to disperse it in a better state in a short time without uneven distribution. It is desirable to mix the lubricating additive in a state where the solid lubricating composition is mixed in a high concentration and dispersed in advance in the base oil.

  The content of the solid lubricating composition in such a lubricating additive is not particularly limited because the mixing amount of the additive itself can be adjusted, but from the viewpoint of the dilution rate and the ease of mixing operation Therefore, it is desirable to add at a rate of about 15 to 1000 g with respect to 1 L of base oil.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, it cannot be overemphasized that this invention is not limited at all by such an Example.

Example 1
(Preparation of solid lubricant composition)
(1) Invention Examples 1-9
As the fluorine-based solid lubricant, polyfluoroethylene (PTFE, average particle diameter: 0.3 μm and 5 μm) manufactured by Kitamura Co., Ltd., and as the hexagonal solid lubricant, tungsten disulfide (WS ₂₎ manufactured by Japan Lubricant Co., Ltd. , Average particle size: 0.2 μm) and Molybdenum disulfide (MoS ₂ , average particle size: 0.2 μm) sold by Daizo Co., Ltd., sold by New Metals End Chemical Corporation as hard particles Nanodiamonds (average particle size: 0.04 μm) were mixed in proportions (mass%) as shown in Table 1 to obtain solid lubricating compositions of Invention Examples 1-9.

(2) Comparative Examples 1-3
Among the above-mentioned fluorine-based solid lubricant, hexagonal solid lubricant and hard particles, as shown in Table 1, two-component compositions excluding one type were prepared, and Comparative Examples 1 to 3 were used. A solid lubricating composition was obtained.

[Preparation of lubricating oil]
Poly-α-olefin (PAO) is used as the lubricating base oil, and 0.385 g of each of the solid lubricating compositions of Invention Examples 1 to 9 and Comparative Examples 1 to 3 prepared as described above is added to 100 mL of the base oil. (3.85 g for 1 L of base oil) and by stirring well, lubricating oils of invention examples and comparative examples were obtained.

[Evaluation of lubricity]
A friction coefficient test apparatus (Crib Tribometer) was used.
Then, 10 μL each of the lubricating oil prepared above was dropped onto the lapping surface of the base material (made of S45C material, 20 mm × 20 mm × 2 mm thickness) with a micropipette, and a 9 mm diameter steel ball made of SUJ2 material was used as the counterpart material. The friction coefficient was measured under the conditions of a radius of 1.5 mm, a friction speed of 8.85 mm / s, a load of 5 N, a measurement environment of 130 ° C., and a substrate temperature of 80 ° C. The results are also shown in Table 1.

The evaluation criteria in the table are as follows.
A: The coefficient of friction is less than 0.1 when 900 seconds have passed. ○: The coefficient of friction exceeds 0.1 and less than 0.3 when 900 seconds have passed. X: The coefficient of friction is 0 within 120 seconds. .5 or more

Example 2 (Fuel consumption test 1 with actual vehicle)
When the fuel consumption of the Subaru Station Wagon manufactured by Fuji Heavy Industries Ltd. was investigated, the average fuel consumption after running 100 km from the time of delivery was 6.9 km / L.

  Next, after resetting the fuel consumption meter of the vehicle, 9.21 g of the solid lubricating composition of Invention Example 1 prepared in Example 1 was added to 4 L of engine oil (2.30 g for 1 L). The average fuel consumption when traveling for 2500 km was 10.4 km / L, which was confirmed to be greatly improved.

Example 3 (Fuel consumption test 2 with actual vehicle)
When the fuel efficiency of the Prius manufactured by Toyota Motor Corporation was investigated, the average fuel efficiency when traveling 100 km from the time of delivery was 19.5 km / L.

  Next, after resetting the fuel consumption meter of the vehicle, 15.35 g of the solid lubricating composition of Invention Example 1 prepared in Example 1 was added to 4 L of engine oil (3.84 g for 1 L). And the average fuel consumption when traveling 2500 km was 22.5 km / L.

Claims (6)

It comprises a fluorine-based solid lubricant having an average particle size of 0.1 to 6 μm, a hexagonal solid lubricant having an average particle size of 0.1 to 6 μm, and nanodiamond having an average particle size of 0.02 to 0.1 μm. Solid lubricating composition. Fluorine-based solid lubricant is polytetrafluoroethylene, the solid lubricating composition according to claim 1, wherein the hexagonal solid lubricant is molybdenum disulfide and / or disulfide tungsten emissions. A mass ratio, a fluorine-based solid lubricant 9-90%, the hexagonal solid lubricant 9-90%, solid lubricant according to claim 1 or 2, characterized in that it comprises a Nanodaiya 0.1 to 9% Composition.   A lubricant composition comprising the solid lubricant composition according to any one of claims 1 to 3.   A lubricating oil comprising the solid lubricating composition according to any one of claims 1 to 3 at a ratio of 0.5 to 30 g per 1 L of base oil.   A lubricating additive comprising 15 to 1000 g of the solid lubricating composition according to any one of claims 1 to 3 with respect to 1 L of base oil.