JP4014445B2 - Engine oil additive and engine oil - Google Patents

Description

【００３６】
【表２】

【００３７】
実施例３
市販のオイルフィルターエレメントからフィルター（濾布）を切り抜いた。実施例２のＢＮ粉末３ｇを自動車のエンジンオイル０．１リットルに混合した液状物を調合し、減圧濾過によって、切り抜いたフィルターを通過させた。通過後のフィルター上に残留物は存在せず、またフィルター表面を走査型電子顕微鏡で観察したところ、ランダムに交錯するフィルター繊維同士の隙間は空間のままであり、フィルターの目詰まりは認められなかった（図１参照）。
【００３８】
比較例１０
市販のＢＮ粉末（電気化学工業社製商品名「ＨＧＰ」：平均粒径５．２μｍ、最大粒径２９．９μｍ、ＧＩ＝１．４、酸化ほう素含有率０．１質量％）を、ボールミルを用い、４８時間連続粉砕することによって、平均粒径２．８μｍ、最大粒径１４．９μｍ、ＧＩ＝２．２、酸化ほう素含有率５．４質量％のＢＮ粉末を製造した。この粉末を用い、実施例３と同様に液状物を調合してフィルターを通過させたところ、フィルター上に白色の残留物が存在し、フィルター表面を走査型電子顕微鏡で観察したところ、フィルター繊維同士の隙間にＢＮ粒子が詰まっており、フィルターの目詰まりが認められた（図２参照）。
【００３９】
実施例４
実施例１の走行試験実施後に、モーターオイルに含まれる水分のｐＨを試験紙にて測定したところ、８であった。
【００４０】
比較例１１
ＢＮ粉末の代わりに、ほう酸のエンジンオイル添加剤（Ａｄｖａｎｃｅｄ Ｌｕｂｒｉｃａｎｔ Ｔｅｃｈｎｏｌｏｇｙ，Ｉｎｃ．社製、商品名「ＭＯＴＯＲＳＩＬＫ」）を、自動車のガソリンエンジンに、エンジンオイル１リットル当たりのほう酸量が１ｇになるように添加した。実施例１と同様の試験走行を行った後、モーターオイルに含まれる水分のｐＨを試験紙にて測定したところ、６であった。
【００４１】
【発明の効果】
本発明によれば、自動車や船舶のガソリンエンジンやディーゼルエンジン等の内燃機関の燃費が節減され、経済性の向上及び環境負荷の低減を実現することができるエンジンオイル添加剤とエンジンオイルが提供される。
【図面の簡単な説明】
【図１】実施例３に係る液状物通過後のフィルターの表面部分の図面代用走査型電子顕微鏡（ＳＥＭ）写真（倍率１００倍）である。
【図２】比較例１０に係る液状物通過後のフィルターの表面部分の図面代用走査型電子顕微鏡（ＳＥＭ）写真（倍率１００倍）である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an engine oil additive used in an internal combustion engine such as a gasoline engine or a diesel engine for automobiles and ships, and an engine oil to which it is added.
[0002]
[Prior art]
In recent years, the improvement of internal combustion engines such as gasoline engines and diesel engines for automobiles and ships has been remarkably improved in order to improve economy and reduce environmental impact by reducing fuel consumption. It's getting on. In response to such demands, for example, JIS standard lubricating oil alone may not be sufficient, and engines using various additives such as graphite, molybdenum disulfide, tetrafluoroethylene (PTFE) resin, organic molybdenum compounds, etc. Attempts have been made to improve oil performance. However, these have advantages and disadvantages.
[0003]
Graphite and molybdenum disulfide have high heat resistance, but are black and opaque, making it difficult to determine when oil has deteriorated. Moreover, since molybdenum disulfide has a large specific gravity, there is a problem that it tends to settle in engine oil. On the other hand, PTFE resin is white and has a low coefficient of friction, but decomposes at a relatively low temperature of about 300 ° C. and generates hydrogen fluoride that is harmful to the human body and corrodes the metal constituting the engine. The organomolybdenum compound is liquid and dissolves in engine oil, so there is no problem of sedimentation like solid additives, and it is excellent in extreme pressure because it enters into narrow gaps. And low.
[0004]
In order to solve such problems, boric acid is added (Japanese Patent Publication No. 11-507676) or hexagonal boron nitride (BN) having an average particle size of 1 μm or less is added to a refined mineral oil together with a surfactant to form a colloidal form. It has been proposed to use the above (Japanese Patent Laid-Open No. 55-23148).
[0005]
Boric acid is a white powder and has a relatively low specific gravity. It is dehydrated at high temperatures to turn into boric anhydride (boron oxide), but it is relatively stable because it does not decompose. However, when the engine is operated, water is generated by the combustion of fuel and mixed into the oil, and boric acid dissolves in the water and becomes acidic, which causes a problem of corroding the metal.
[0006]
BN is also a white powder like boric acid, has a relatively small specific gravity, and is stable up to a high temperature around 1000 ° C. The reason why BN has an excellent lubricating performance as an engine oil additive is that it has a scaly particle shape derived from a crystal structure and a property of being easily cleaved in a direction parallel to the surface of the particle. However, as disclosed in Japanese Patent Application Laid-Open No. 55-23148, when pulverized to 1 μm or less, the scale shape is not maintained and an isotropic particle shape is exhibited. Even if the performance increases, the lubrication performance does not improve as expected. Furthermore, the BN particles which are difficult to cleave like this exhibit wear resistance due to the strong covalent bond between the nearest boron atom (B) and nitrogen atom (N) constituting BN. There is concern about damaging the engine.
[0007]
[Problems to be solved by the invention]
The present invention has been made in view of the above, and an object thereof is to reduce the fuel consumption of an internal combustion engine by adding it to engine oil, and to realize an excellent engine oil additive that achieves economic improvement and environmental load reduction. It is added to provide engine oil. The object of the present invention can be achieved by using BN powder having a relatively large average particle size and optimizing the particle size constitution, graphitization index (GI), and boron oxide content.
[0008]
[Means for Solving the Problems]
That is, the present invention has an average particle size of more than 1.0 μm to 3.0 μm or less, a maximum particle size of 15 μm or less, a graphitization index (GI) of 4.0 or less by powder X-ray diffraction method, and a boron oxide content of 0.5 to An engine oil additive comprising 5% by mass of hexagonal boron nitride powder. The present invention also has an average particle size of more than 1.0 μm and 2.0 μm or less, a maximum particle size of 7.5 μm or less, a graphitization index (GI) of 3.5 or less by powder X-ray diffraction method, and a boron oxide content of 0. An engine oil additive comprising 8 to 4% by mass of hexagonal boron nitride powder. Furthermore, the present invention is an engine oil in which 1 to 10 g of the engine oil additive of the present invention is added per liter of engine oil .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
[0010]
The first condition of the engine oil additive of the present invention is that the BN powder has an average particle size of more than 1.0 μm and 3.0 μm or less and a maximum particle size of 15 μm or less. When the average particle size is 1.0 μm or less, it can no longer be said to be scaly BN particles, and also exhibits no cleaving property. Therefore, even if the dispersibility in oil is improved, the lubricating performance is not sufficiently enhanced. If the average particle size is more than 3.0 μm, the engine oil may cause sedimentation. A particularly preferable average particle size is more than 1.0 μm and not more than 2.0 μm.
[0011]
On the other hand, an oil filter is disposed in the engine in order to remove foreign matters mixed in the oil. Normally, the opening of the filter is about several tens to 100 μm, so if an additive containing BN powder with a maximum particle size exceeding 15 μm is used, the filter will be clogged, so the maximum particle size must be 15 μm or less. is required. A particularly preferable maximum particle size is 7.5 μm or less.
[0012]
The second condition is that the BN powder has a graphitization index (GI) by a powder X-ray diffraction method of 4.0 or less. GI is an equation, GI = [area {(100) + (101)}, from the integrated intensity ratio (ie, area ratio) of (100), (101) and (102) diffraction lines in the X-ray diffraction diagram of BN powder. / [Area (102)] (J. Thomas. Et.al, J. Am. Chem. Soc., 84, 4619 [1962]).
[0013]
GI is an index of the crystallinity of BN powder. The higher the crystallinity, the smaller this value, and the scale shape of particles develops, and the GI of fully crystallized (graphitized) GI is about 1.6. It is supposed to be. In the BN powder having a GI of more than 4.0, the crystallinity and scale shape are insufficient, and the lubrication performance does not increase. Just as BN powders with a GI of 4 or less are known, BN powders with a GI of more than 4 are also known (for example, the product name “HPP325” manufactured by Carborundum, average particle size of 3 μm, GI = about 5 to 6). . In the present invention, BN powder having a GI of 4 or less is used. Particularly preferred GI is 3.5 or less. The GI of the BN powder can be reduced by increasing the firing / crystallization temperature during the production of the BN powder (see, for example, JP-A-11-79720).
[0014]
The third condition is that the BN powder has a boron oxide content of 0.5 to 5% by mass. Ordinary BN powder contains a trace amount of oxygen as an impurity and is removed as much as possible. The existence form of oxygen impurities is classified into those existing inside the powder particles and those existing on the surface of the particles. The former is called internal oxygen, and the latter is called surface oxygen. While internal oxygen is tightly bound within the particles, surface oxygen is loosely bound, and most exists in the form of boron oxide soluble in water and alcohol. The boron oxide regulated in the present invention is this surface oxygen.
[0015]
In the present invention, the reason why the boron content is limited to 0.5 to 5% by mass, which is larger than that of the normal product, is as follows.
[0016]
Although the BN particles have a cleavage property, the bond between the nearest B atom and N atom is a strong covalent bond, so that wear resistance is exhibited, and there is a concern that the engine may be damaged. Such a problem is likely to occur particularly in the early stage of using the additive. This is because, after a certain period of time has elapsed since the addition, BN particles are hydrolyzed under the influence of moisture contained in the engine oil and the high temperature of the engine to produce boron oxide on the surface, which acts as a lubricant. This is because damage to the engine can be suppressed. Therefore, if a certain amount of boron oxide is present on the surface of the BN particles from the beginning, such a concern can be eliminated.
[0017]
As described above, there is a concern that boron oxide dissolves in water generated by the combustion of fuel and corrodes the metal. However, in the present invention, when BN particles are hydrolyzed, not only boron oxide but also ammonia is generated, and when it is dissolved in water, the water coexisting with the BN particles after hydrolysis becomes neutral or weakly alkaline. Therefore, there is no concern that the metal is corroded.
[0018]
If the boron oxide content is less than 0.5% by mass, boron oxide hardly acts as a lubricant, and if it exceeds 5% by mass, BN particles aggregate and become difficult to disperse in the engine oil. Clogging is likely to occur. A particularly preferable boron oxide content is 0.8 to 4% by mass.
[0019]
Japanese Patent Application Laid-Open No. 55-23148 discloses that “many BN powders are mostly about 1 to 5 microns”. However, since commercially available BN powder is manufactured so as not to contain oxygen impurities as much as possible, the oxygen boron content is less than 0.5% by mass. For example, the trade name “UHP-S1” manufactured by Showa Denko KK has an average particle size of 1 to 2 μm and a boron oxide content of 0.30% by mass, and Mitsui Chemicals products have an average particle size of 1.7 μm and boron oxide. The elemental content is 0.1%.
[0020]
The engine oil additive of the present invention can be produced, for example, by using BN powder having a GI of 4 or less and adjusting the particle size constitution and boron oxide content according to pulverization / classification conditions. As the pulverizer, a jet pulverizer (for example, JP-A-10-67507, JP-A-10-87990) is suitable. In this case, the pulverization to an average particle size of 1.0 μm or less is excessive, and the pulverization conditions need to be adjusted because the pulverization is more than 1.0 μm and 3.0 μm or less. For example, a commercially available jet crusher (trade name “STJ-200” manufactured by Seishin Enterprise Co., Ltd.) can supply BN powder at a feed rate of 0.5 to 1.0 kg / hr and a carrier air pressure of 0.4 to 0.7 MPa. is there. The maximum particle size is controlled by classification. In the present invention, an air classifier such as a cyclone type can be used.
[0021]
The boron oxide content is preferably adjusted by the temperature and humidity of the carrier air during jet pulverization. The higher the temperature and humidity, the more easily the amount of boron oxide increases. The temperature and humidity of the carrier air suitable for the production of the BN powder according to the present invention are 15 to 35 ° C. and 30 to 80% (relative humidity).
[0022]
The average particle size, maximum particle size, and boron oxide content are adjusted by the above method, and the engine oil additive is made of BN powder having no aggregation and good dispersibility. The additive of the present invention can be used alone in powder form, or can be used after being dispersed in a small amount of engine oil in advance for convenience during injection. The preferred amount used is 1-10 g of BN powder per liter of engine oil. Moreover, it can also use together with surfactant, extreme pressure agent, a rust preventive agent, sludge washing | cleaning dispersing agent, etc. as needed.
[0023]
【Example】
Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples.
[0024]
Example 1
Commercially available BN powder (trade name “SP-2” manufactured by Denki Kagaku Kogyo Co., Ltd .: average particle size 3.8 μm, maximum particle size 59.7 μm, GI = 3.1, boron oxide content 0.3% by mass) Using a jet crusher (trade name “STJ-200” manufactured by Seishin Enterprise Co., Ltd.), after pulverization under conditions of BN powder supply amount = 0.5 kg / hr, conveyance air pressure 0.4 MPa, temperature 20 ° C., humidity 70%, BN powder having an average particle size of 1.4 μm, a maximum particle size of 7.5 μm, GI = 3.2, and a boron oxide content of 2.1% by mass was manufactured by airflow classification using a cyclone classifier.
[0025]
The average particle size was measured with a laser diffraction / scattering particle size distribution analyzer (trade name “Microtrac SPA, Model-7997-20” manufactured by LEEDS & NORTH UP). GI was measured under the conditions shown in Table 1 using a powder X-ray diffractometer (trade name “GF-2013” manufactured by Rigaku Corporation). The boron oxide content is determined by adding methanol to BN powder, heating at 70-80 ° C. to react boron oxide with methanol to volatilize as trimethyl borate, and then heating at 120 ° C. to remove excess methanol. After all were volatilized, the mass was measured and quantified by the weight loss from before methanol addition.
[0026]
The obtained BN powder was stirred and mixed with commercially available engine oil (trade name “Toyota Castle Royal” manufactured by Tacty Co., Ltd.) so that the mass ratio of oil: BN powder = 50: 1, and then a gasoline engine for automobiles. The amount of BN powder per liter of engine oil was added to 1 g. Thereafter, a test run of 2000 km was performed on the highway at 80 km / hr, and the fuel consumption was measured for each travel distance. The car used a 1989 sedan with a displacement of 2000cc. The results are shown in Table 2 together with the results of Example 2 and Comparative Examples 1-9.
[0027]
Comparative Example 1
A running test similar to Example 1 was performed without adding BN powder.
[0028]
Example 2
Commercially available BN powder (trade name “GP” manufactured by Denki Kagaku Kogyo Co., Ltd .: average particle size 8.2 μm, maximum particle size 42.2 μm, GI = 1.2, boron oxide content 0.1 mass%) was jetted. Using a pulverizer, BN powder supply amount = 0.7 kg / hr, conveying air pressure 0.6 MPa, air temperature 30 ° C., humidity 50%, and then air classifying with a cyclone classifier to obtain an average particle size of 2 A BN powder having a diameter of 0.6 μm, a maximum particle size of 10.6 μm, GI = 1.8, and a boron oxide content of 0.8% by mass was produced. This was added to an automobile gasoline engine so that the amount of BN powder per liter of engine oil was 2 g, and then a running test was conducted in the same manner as in Example 1.
[0029]
Comparative Example 2
In Example 2, BN powder supply amount = 1.5 kg / hr, conveyance air pressure 0.6 MPa, air temperature 30 ° C., humidity 70%, jet pulverization, airflow classification with a cyclone classifier, average particle size 2 A BN powder having a thickness of 9.9 μm, a maximum particle size of 21.1 μm, GI = 1.6, and a boron oxide content of 0.6% was produced. A vehicle running test was conducted in the same manner as in Example 2 except that this was used as an additive.
[0030]
Comparative Example 3
Commercially available BN powder (trade name “SGP” manufactured by Denki Kagaku Kogyo Co., Ltd .: average particle size 18.8 μm, maximum particle size 59.7 μm, GI = 0.9, boron oxide content 0.05 mass%) After crushing using a pulverizer under the conditions of BN powder supply amount = 1.2 kg / hr, conveyance air pressure 0.6 MPa, temperature 35 ° C., humidity 80%, and classifying the airflow with a cyclone classifier, the average particle size 3 A BN powder having a diameter of 0.5 μm, a maximum particle size of 14.9 μm, GI = 1.5, and a boron oxide content of 1.2% by mass was produced. A vehicle running test was conducted in the same manner as in Example 2 except that this was used as an additive.
[0031]
Comparative Example 4
In Example 1, after pulverizing under the conditions of BN powder supply amount = 0.1 kg / hr, conveyance air pressure 0.8 MPa, air temperature 25 ° C., humidity 60%, airflow classification is performed with a cyclone classifier, and the average particle size is 0. A BN powder having a diameter of 8 μm, a maximum particle size of 7.5 μm, GI = 3.8, and a boron oxide content of 1.4% by mass was produced. A vehicle running test was conducted in the same manner as in Example 2 except that this was used as an additive.
[0032]
Comparative Example 5
Commercially available BN powder (trade name “HPP-325” manufactured by Carborundum): average particle size 3.1 μm, maximum particle size 42.2 μm, GI = 4.9, boron oxide content 1.9% by mass) Using the same jet pulverizer as in Example 1, after pulverizing under the conditions of BN powder supply amount = 0.7 kg / hr, conveying air pressure 0.5 MPa, temperature 30 ° C., humidity 60%, airflow classification with a cyclone classifier, A BN powder having an average particle size of 1.2 μm, a maximum particle size of 10.6 μm, GI = 5.3, and a boron oxide content of 2.6% was produced. A vehicle running test was conducted in the same manner as in Example 2 except that this was used as an additive.
[0033]
Comparative Example 6
After pulverizing under the same conditions as in Example 2 except that nitrogen gas was used instead of air for conveying BN powder, airflow classification was performed with a cyclone classifier, and the average particle size was 2.8 μm, the maximum particle size was 14.9 μm, GI = 1.7, BN powder having a boron oxide content of 0.4% by mass was produced. A vehicle running test was conducted in the same manner as in Example 2 except that this was used as an additive.
[0034]
Comparative Examples 7-9
Commercially available BN powder, trade name “UHP-S1” manufactured by Showa Denko KK: average particle size 1.9 μm, maximum particle size 14.9 μm, GI = 3.2, boron oxide content 0.30% by mass (comparative example) 7), Mitsui Chemicals products: average particle size 1.7 μm, maximum particle size 7.5 μm, GI = 2.4, boron oxide content 0.1% by mass (Comparative Example 8), product name “Carborundum” HPP325 ”: average particle size of 3.1 μm, maximum particle size of 42.2 μm, GI = 4.9, boron oxide content of 1.9% by mass (Comparative Example 9) were used as additives without being crushed. Except for this, an automobile running test was carried out in the same manner as in Example 2.
[0035]
[Table 1]

[0036]
[Table 2]

[0037]
Example 3
A filter (filter cloth) was cut out from a commercially available oil filter element. A liquid material in which 3 g of BN powder of Example 2 was mixed with 0.1 liter of automobile engine oil was prepared and passed through a cut-out filter by vacuum filtration. There is no residue on the filter after passing, and when the surface of the filter is observed with a scanning electron microscope, the gaps between the filter fibers that are randomly intermingled remain as spaces, and the filter is not clogged. (See FIG. 1).
[0038]
Comparative Example 10
Commercially available BN powder (trade name “HGP” manufactured by Denki Kagaku Kogyo Co., Ltd .: average particle size 5.2 μm, maximum particle size 29.9 μm, GI = 1.4, boron oxide content 0.1 mass%) Was used to produce a BN powder having an average particle size of 2.8 μm, a maximum particle size of 14.9 μm, GI = 2.2, and a boron oxide content of 5.4% by mass. Using this powder, a liquid material was prepared and passed through the filter in the same manner as in Example 3. As a result, a white residue was present on the filter, and the surface of the filter was observed with a scanning electron microscope. BN particles were clogged in the gap, and clogging of the filter was observed (see FIG. 2).
[0039]
Example 4
It was 8 when pH of the water | moisture content contained in motor oil was measured with the test paper after the running test of Example 1 was implemented.
[0040]
Comparative Example 11
Instead of BN powder, boric acid engine oil additive (Advanced Lubricant Technology, Inc., trade name “MOTORSILK”) is applied to automobile gasoline engines so that the amount of boric acid per liter of engine oil is 1 g. Added. After running the same test run as in Example 1, the pH of the moisture contained in the motor oil was measured with a test paper and found to be 6.
[0041]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the engine oil additive and engine oil which can reduce the fuel consumption of internal combustion engines, such as a gasoline engine of a motor vehicle or a ship, and a diesel engine, can implement | achieve improvement of economical efficiency and reduction of an environmental load are provided. The
[Brief description of the drawings]
FIG. 1 is a drawing-substitute scanning electron microscope (SEM) photograph (magnification 100 times) of a surface portion of a filter after passing through a liquid according to Example 3.
2 is a drawing-substitute scanning electron microscope (SEM) photograph (magnification 100 times) of a surface portion of a filter after passing through a liquid according to Comparative Example 10. FIG.

Claims (3)

  Hexagonal crystal having an average particle size of more than 1.0 μm and a maximum particle size of 15 μm or less, a graphitization index (GI) of 4.0 or less by powder X-ray diffraction method, and a boron oxide content of 0.5 to 5% by mass An engine oil additive characterized by comprising boron nitride powder. Average particle size greater than 1.0 μm and less than 2.0 μm, maximum particle size of 7.5 μm or less, graphitization index (GI) by powder X-ray diffraction method of 3.5 or less, boron oxide content of 0.8-4% by mass An engine oil additive comprising hexagonal boron nitride powder. 1 to 10 g of engine oil additive according to claim 1 or 2 is added per liter of engine oil.

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