JPH06271885A - Lubricating oil for diesel engine - Google Patents

Abstract

PURPOSE:To obtain the subject lubricating oil capable of preventing corrosion caused by sulfuric acid by containing an amine molybdenum complex compound and a specific alkenylsuccinimide in a mineral base or synthetic lubricating ail, etc. CONSTITUTION:This lubricating oil consists of (A) a lubricating oil base material derived from a mineral oil or a synthetic oil and (B) 0.1-5%, by weight, (preferably 0.3-1%) at least one amine molybdenum complex compound of formula I (R1 and R2 are each 3-25C alkyl; X, Y and Z are each 1-3), (e.g. a reactional product of molybdenum oxide and amine) and (C) 1-10% (preferably 2-3%) bis-type alkenylsuccinimide of formula II (R3 is polybutenyl group having 1000-3000 average molecular weight; R4 is 2-5C bivalent saturated hydrocarbon group; (x) is 0-10) or its derivative (e.g. a boron compound derivative, an organophosphonate derivative, etc.) or a mixture of them, and as necessary, an abrasion preventing agent, antioxidant, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diesel engine lubricating oil which can effectively prevent corrosive wear due to sulfuric acid, which is remarkably found in diesel engines.

[0002]

2. Description of the Related Art Generally, a fuel used in a diesel engine has a large amount of sulfur, and therefore a large amount of sulfur oxide (hereinafter referred to as "SOx") is contained in a diesel engine exhaust gas.
Will be included. This large amount of SOx reacts with moisture existing in the surroundings to generate a large amount of sulfuric acid. The large amount of generated sulfuric acid breaks the oil film of the diesel engine lubricating oil, corrodes and wears the constituent materials of the diesel engine. In particular, the cylinder liner and the piston ring are parts that are subject to severe corrosive wear, and having the ability to prevent this corrosive wear is extremely important for diesel engine lubricating oils.

In conventional diesel engine lubricating oil,
When a certain amount or more of the high base number metal type detergent is added, for example, 0.5% by weight or more, a large amount of sulfuric acid is neutralized by the high base number metal type detergent to which a large amount is added. It has been understood that the problem of corrosive wear on liners and piston rings does not occur.

[0004]

By the way, in recent land diesel engines, as a measure against exhaust gas, a system (Exhaust gas) that circulates exhaust gas and re-combusts it.
s recirculation, abbreviated as "EGR"), SOx in the exhaust gas shows a tendency to increase more than in conventional diesel engine exhaust gas. Also, in the marine diesel engine, recently
In order to save costs, low-quality fuels having a high sulfur content have been increasingly used, and SOx in exhaust gas has a tendency to increase, as in land diesel engines.

The large amount of sulfuric acid generated by the reaction of such a large amount of SOx with the surrounding water causes the addition amount of the high-base metal type detergent like the conventional diesel engine lubricating oil described above. A simple increase does not neutralize to the extent that corrosive wear can be prevented. In other words, the conventional countermeasures for increasing the amount of the high base number metal type detergent are not sufficient for preventing the corrosive wear.

The present invention provides a lubricating oil for use in a diesel engine that emits a large amount of SOx, and an engine lubricating oil that exhibits excellent corrosion and wear resistance against the large amount of SOx that is emitted. The purpose is to do.

[0007]

Means for Solving the Problems The present inventors have previously conducted a study paying attention to the above-mentioned neutralization rate of sulfuric acid, and as a result, a metal base detergent having a high base number was identified as an additive. It was found that by adding a nonionic surfactant, it is possible to provide an engine lubricating oil that can significantly suppress the corrosive wear of the cylinder liner and the piston ring, and "land diesel engine oil composition" (Japanese Patent Application No. 4- (No. 78538)
Is proposed as.

The inventors of the present invention have studied the corrosion wear phenomenon from the viewpoint of preventing the oil film from being broken by sulfuric acid based on the previously proposed one. As a result, the alkenyl succinimide is
When an amine molybdenum complex compound was blended, it was found that a diesel engine lubricating oil capable of optimally preventing the corrosive wear of the cylinder liner and piston ring was obtained in the same manner as the previously proposed one, and the present invention was completed. It was

That is, the lubricating oil for diesel engines of the present invention comprises a mineral oil or a synthetic oil type lubricating oil as a base material, to which at least one of the amine molybdenum complex compounds represented by the general formula (A) is used. 0.1 to 5% by weight, (B) 1 to 10% by weight of a bis type alkenyl succinimide having a polybutenyl group having an average molecular weight of 1000 to 3000 or a derivative thereof or a mixture of both. To do.

[0010]

[Chemical 2]

As the base material of the diesel engine lubricating oil of the present invention, both mineral oil type lubricating oil and synthetic oil type lubricating oil can be favorably used.

Among the additives to be added to the above base material,
The amine-molybdenum complex compound represented by the general formula of Chemical formula 2 which is the component (A) is, for example, molybdenum oxide, molybdic acid or an alkali salt thereof (eg, sodium salt, potassium salt, ammonium salt), or the like, The resulting product (hereinafter collectively referred to as “molybdenum compound”) can be prepared by reacting with amines.

Any reducing agent may be used as a reducing agent for reducing the above molybdenum oxide, molybdic acid or its alkali salt, as long as it has a reducing power capable of reducing these. For example, sodium sulfoxylate, sodium dithionite, sodium sulfite, sodium hydrogen sulfite, sodium pyrosulfite, sodium thiosulfate, sodium dithiosulfate, other alkali metal salts, alkaline earth metal salts; hydrogen sulfide, sulfur dioxide, etc. Reducing compounds of glucose; reducing sugars such as glucose, maltose, lactose, maltotriose, manninotriose; aldehydes such as formaldehyde, acetaldehyde, propionaldehyde; formic acid, oxalic acid,
Examples thereof include reducing acids such as ascorbic acid and salts thereof. These reducing agents may be used alone or in admixture of two or more.

The amount of the reducing agent used may be appropriately selected according to the desired degree of reduction of molybdenum oxide, molybdic acid or a salt thereof. However, if the degree of reduction is too small, the corrosion resistance of the amine molybdenum complex compound is prevented. This effect cannot be made excellent, and even if it is too much, this effect is saturated, so that it is about 1: 0.3 to 1: 3 equivalent, preferably 1 to molybdenum oxide, molybdic acid or a salt thereof. It is suitable to be about 1: 1 to 1: 1.5 equivalent.

The reduction reaction is carried out in water at room temperature to about 100 ° C.
Within the temperature range of. The reaction time at this time varies depending on the type of the reducing agent used and the reaction temperature conditions. For example, when sodium hydrosulfide is used as the reducing agent, when the reaction temperature is about 60 ° C., the reaction time is about 1.5 hours or less, about 90 hours or less. It is sufficient to keep the temperature at about 1 hour or less within about 1 hour, and when another reducing agent is used, the temperature and time may be adjusted according to the reducing power of the reducing agent.

The amines to be reacted with the molybdenum compound are monoamines having about 6 to 24 carbon atoms, such as methylamine, ethylamine, n-propylamine, n-butylamine, n-octylamine, laurylamine, Linear primary amines such as stearylamine; alicyclic primary amines such as isopropylamine, isobutylamine, 2-ethylcyclohexylamine; primary amines having aromatic ring substituents such as benzylamine and 4-methylbenzylamine; dimethyl. Linear secondary amines such as amines, diethylamine, di-n-propylamine, di-n-butylamine, di-n-octylamine, dilaurylamine, distearylamine; diisopropylamine, diisobutylamine, di-2-ethylhexyl. Amine, branched Branched 2 such as decyl) amine
Alicyclic secondary amines such as dicyclohexylamine and di-2-methylcyclohexylamine; secondary amines having an aromatic ring substituent such as dibenzylamine and di-4-methylbenzylamine; methyl-n- Butylamine, ethyl-laurylamine, ethyl-stearylamine, isopropyl-n-octylamine, isobutyl-
2-ethylhexylamine, cyclohexyl-2-ethylhexylamine, cyclohexyl-benzylamine,
Unsymmetrical secondary amines such as stearyl-benzylamine, 2-ethylhexyl-benzylamine; trimethylamine, triethylamine, tri-n-propylamine,
Tri-n-butylamine, tri-n-octylamine,
Linear tertiary amines such as trilaurylamine, tristearylamine; branched tertiary amines such as triisopropylamine, triisobutylamine, tri-2-ethylhexylamine, branched tri (tridecyl) amine; tricyclohexylamine Such alicyclic tertiary amines; tertiary amines having aromatic ring substituents such as tribenzylamine, tri-4-methylbenzylamine, dimethyloctylamine, dimethyllaurylamine, dimethylstearylamine, diethyllaurylamine, dimethylbenzyl Tertiary amines having mixed hydrocarbon groups such as amines and dimethylcyclohexylamine; dispersants for succinimide carboxylic acid amides having a hydrocarbon group with a molecular weight of about 70 to 250,000 and having an amino nitrogen atom, hydrocarbon-based polyamines, etc. Amination Things and the like. Among them, linear secondary amines such as di-n-butylamine and di-n-octylamine are amine-molybdenum complex compounds that can effectively neutralize sulfuric acid and thus effectively prevent corrosive wear. It can be preferably used in preparation. These amines can be used alone or in admixture of two or more.

The amount of amines used is theoretically 1: 1/3 to 1: 3 equivalent to the above-mentioned molybdenum compound, but in order to allow good reaction with the molybdenum compound,
Preferably in excess of stoichiometric amount, specifically 1: 1 to 1:
Use about 9. Unreacted amines remaining when used in excess may be removed by neutralizing with an acid (for example, hydrochloric acid or sulfuric acid) after the reaction is completed.

The reaction with amines is carried out within the temperature range of room temperature to about 80 ° C., as in the case of the reaction between molybdenum oxide, molybdic acid or a salt thereof and the reducing agent. The reaction time is not particularly limited, but if it is too short, the reaction does not proceed sufficiently, and if it is too long, the reaction is saturated,
Generally, about 1 to 2 hours is preferable.

The amine-molybdenum complex compound obtained as described above is generally in a state in which several compounds represented by the general formula of Chemical formula 2 are mixed. In some cases, a single amine molybdenum complex compound may be obtained. In the present invention, the one in this state (that is, a state in which several kinds are mixed or a single state) can be used as it is as the component (A). The compounding ratio of such an amine molybdenum complex compound is about 0.1 to 5% by weight, preferably about 0.1.
3 to 1.0% by weight. If it is less than about 0.3% by weight, the effect of preventing corrosion and wear cannot be obtained, and if it is more than about 5% by weight, the effect is saturated and it is economically disadvantageous.

The other additive, component (B), alkenyl succinimide or derivative thereof, has an average molecular weight of 1000 to 3000, preferably 1300 to 2
A bis-type alkenyl succinimide or a derivative thereof having a polybutenyl group of 500, which is represented by the general formula (3).

[0021]

[Chemical 3]

In the formula (3), R ³ represents a polybutenyl group which is an alkenyl group having an average molecular weight of 1000 to 3000, and —R ⁴ — represents a divalent saturated aliphatic hydrocarbon having 2 to 5 carbon atoms. Represents a group, and x represents an integer of 0 to 10. If the average molecular weight of the polybutenyl group is too small, a good effect of preventing corrosion and wear cannot be obtained, and if it is too large, not only this effect is saturated, but also the manufacturing cost increases, which is economically disadvantageous. .

The above-mentioned bis-type alkenyl succinimide or its derivative is generally synthesized by reacting polybutenyl succinic anhydride obtained by reaction of polybutene with maleic anhydride and polyamine. Examples of this polyamine include single diamines such as ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, etc .; polyalkylenepolyamines such as diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, di (methyl). Examples thereof include ethylene) triamine, dibutylenetriamine, tributylenetetramine, and pentapentylenehexamine.

As examples of bis-type alkenyl succinimide derivatives, Japanese Patent Publication Nos. 42-8013 and 42-8014, JP-A-51-52381 and JP-A-51-1 are cited.
No. 30408, a boron compound derivative of alkenyl succinimide, an organic phosphonate derivative, or the like, or an alkenyl succinimide is used as an aldehyde, ketone, carboxylic acid, sulfonic acid, alkylene oxide, sulfur, polyvalent Examples thereof include alkenyl succinimide derivatives reacted with alcohol and the like.

The compounding ratio of the above-mentioned alkenyl succinimide or its derivative or a mixture of both is about 1 to 1.
It is 10% by weight, preferably about 2.0-3.0% by weight. If it is less than about 1% by weight, the effect of preventing corrosion and wear cannot be obtained, and if it is more than about 10% by weight, the effect is saturated and it is economically disadvantageous.

In the diesel engine lubricating oil of the present invention, in addition to the components (A) and (B) described above, an antiwear agent, an antioxidant, a corrosion inhibitor, a viscosity index improver, a pour point depressant, Additives such as defoamers may also be included.

Of these, zinc dialkyldithiophosphate can be used as the antiwear agent, amine-based and phenol-based antioxidants can be used as the antioxidant, and benzotriazole and alkenyl can be used as the corrosion inhibitor. Succinate, etc. can be used. In general, the blending ratio of these additives is preferably about 0.1 to 3% by weight in the diesel engine lubricant of the present invention.

As the viscosity index improver, polymethacrylate, olefin copolymer or the like can be used, as the pour point depressant, polymethacrylate or the like can be used, and as the defoaming agent, a silicon compound or the like can be used. It is suitable that the blending ratio of these additives is generally about 20% by weight or less, and preferably about 10% by weight or less, in the lubricant for a diesel engine of the present invention.

The lubricating oil for diesel engines of the present invention described in detail above can be suitably used for diesel engines regardless of whether it is for land use or sea use.
It is preferably used in diesel engines equipped with R.

[0030]

【Example】

Examples 1 to 5 and Comparative Examples 1 to 15 The respective components were mixed in the proportions shown in Tables 1 to 6 to prepare lubricating oils for diesel engines of Examples and Comparative Examples. The lubricating oils for diesel engines of Examples and Comparative Examples in Tables 1 to 6 all have a base number of 14.5 mgK.
Adjusted to OH / g. Further, the blending ratios in Tables 1 to 6 are shown by weight%. The lubricating oil of each of these Examples and Comparative Examples was evaluated by an oil film breakage evaluation test with sulfuric acid in the following manner, and the results are also shown in Tables 1 to 6.

Oil film breakage evaluation test procedure; (1) Microscopic observation method: JIS steel plate (JIS G3141)
On the SPCC-SB), about 15 mg of the lubricating oils of Examples and Comparative Examples are dropped as a test oil. After allowing an oil film formation time of 1 minute, 10 μl of concentrated reagent-grade concentrated sulfuric acid is added dropwise. At the same time, the time until the reaction takes place between the sulfuric acid and the steel sheet is measured with an optical microscope (magnification × 10). The longer the reaction time is, the higher the effect of suppressing the oil film breakage is evaluated. (2) Sulfuric acid solution immersion method: 0.1% sulfuric acid solution 500 ml
In the test oil, the lubricating oil of the example and comparative example
A JIS steel plate treated by the coating method specified in IS K 2246 (5.3. 3) is immersed. The amount of dissolved iron in the sulfuric acid solution after the immersion for 8 hours is quantified by a plasma emission spectrometer. The smaller the dissolved iron content, the higher the effect of suppressing the oil film breakage is evaluated.

[0032]

[Table 1]

The symbols in Table 1 are as follows. * 1: SAE30 (American Automobile Engineers Association automotive lubricant viscosity number # 30 and 100 ° C. viscosity 9.3 to 12.5 cSt) is used. * 2: Base number 170 mgKOH / g * 3: N amount = 1.6 Wt%, average molecular weight of polybutenyl group = 1900 * 31: N amount = 1.6 Wt%, average molecular weight of polybutenyl group = 2400 * 32: N amount = 2.1 wt%, average molecular weight of polybutenyl group = 700 * 4: Zn amount = 8.9 Wt%, P amount = 7.4 Wt%, S
Amount = 15.0 Wt% * 5: Olefin Copolymer (OCP) * 6: Polymethacrylate (PMA) * 7: R ¹ , R ² = n-octyl, X, Y, Z = 1,
Mo amount = 4.6Wt%

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

[Table 6]

Examples 4 and 5 and Comparative Example 15 shown in Table 6
Regarding the lubricating oil of No. 3, the lubricating oil for diesel engine actually used was prepared by the composition shown in the table. These were used in a diesel engine equipped with EGR, and the average EG
R rate [= intake CO ₂ / (exhaust CO ₂ −intake CO ₂ ) 10
0] is 30%, the average engine speed is 1500 rpm
The continuous operation was carried out for 200 hours. As a result, the average wear amounts of the cylinder liner and the piston ring when the lubricating oil for diesel engines of the present invention of Example 4 was used were 12 μm and 21 mg, respectively.
The average wear amounts of the cylinder liner and the piston ring when the diesel engine lubricating oil of the present invention is used are 18 μm and 28 mg, respectively, and the cylinder liner when the conventional diesel engine lubricating oil of Comparative Example 15 is used. And the amount of corrosive wear of the piston ring were significantly reduced as compared with 58 μm and 52 mg, respectively.

[0040]

As described in detail above, the lubricating oil for a diesel engine of the present invention is suitable for a diesel engine that emits a large amount of SOx, and is particularly suitable for a diesel engine equipped with EGR. That is, since the diesel engine lubricating oil of the present invention exhibits extremely high oil film retention with respect to sulfuric acid, it is corroded by sulfuric acid due to sulfuric acid of EGR used as a recent automobile exhaust gas countermeasure and diesel engine using low quality fuel. Can be effectively reduced.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C10N 30:06 30:12 40:25 (72) Inventor Koichi Sakamoto 1134 Gongendo, Satte City, Saitama Prefecture 2 Cosmo Research Institute Co., Ltd. Research and Development Center

Claims (1)

[Claims] 1. A mineral oil or synthetic oil-based lubricating oil as a base material,
To this, at least one of the amine molybdenum complex compounds represented by the general formula (A) 1 is added in an amount of 0.1 to 5
% By weight, (B) A diesel engine lubricating oil comprising 1 to 10% by weight of a bis type alkenyl succinimide having a polybutenyl group having an average molecular weight of 1000 to 3000 or a derivative thereof or a mixture of both.