JPH11246882A - Engine oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an engine oil composition having a combination of excellent metal corrosion-resisting performance and valve operating abrasion-proofing performance. SOLUTION: This engine oil composition is obtained by incorporating an engine base oil selected from mineral oils and synthetic oils with the following ingredients: (A) 0.01-0.1 wt.%, on a boron basis, of a boron compound derivative of alkenylsuccinimide, (B) 0.2-3 wt.% of a polysulfide, and (C) 0.01-2 wt.% of an alkylated thiadiazole and/or derivative thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in engine oil, and provides an engine oil composition having high anti-wear performance and excellent anti-corrosion performance.

[0002]

2. Description of the Related Art In recent years, in consideration of the improvement of engine output and the improvement of flammability due to the tightening of exhaust gas regulations, the amount of a conventionally used phosphorus-containing antiwear agent has been reduced. There is a tendency to decrease. In such a case, it may not be easy to maintain the anti-wear performance of the engine for a long period of time. Therefore, a method for maintaining the anti-wear performance is required.

As one measure, a friction modifier containing Mo or an ashless friction modifier of amine or ester type is often added. However, these additives are known to have a large friction reducing effect.However, depending on the additive and the amount added, the consumption rate may increase due to oxidative deterioration, and the performance of the engine oil is maintained for a long time. May not be expected to do so.

[0004] Separately, it is becoming increasingly common to add considerably large amounts of ashless dispersants such as succinimides to engine oils. This type of ashless dispersant disperses finely the diesel suits (in the case of diesel engines) generated during combustion and the sludge generated by oxidative deterioration of engine oil to prevent them from adhering to engine parts. This has the effect of improving the cleanliness of each part of the engine. However, this kind of ashless dispersant may reduce the effect of suppressing corrosion wear on engine parts, especially on main metal, connecting rod metal, etc., depending on the additives and amounts added.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an engine oil composition having both excellent metal corrosion resistance and valve valve abrasion prevention performance in view of the above-mentioned state of the art. I do.

[0006]

Means for Solving the Problems As a result of intensive studies, the inventors have selected a specific ashless dispersant which has been conventionally added, and combined it with a specific amount of polysulfide and alkylated thiadiazole. It has been found that the above-mentioned object can be achieved by adding it to a base oil of an engine oil, and the present invention has been completed.

Accordingly, the engine oil composition of the present invention comprises the following components added to an engine base oil selected from mineral oil or synthetic oil: (A) a boron compound derivative of alkenylsuccinimide; 0.01 to 0.1% by mass in terms of boron, (B)
0.2 to 3% by mass of polysulfide and 0.01 to 2% by mass of (C) at least one alkylated thiadiazole or a derivative thereof.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the boron compound derivative of alkenyl succinimide which is the component A to be added to the engine oil base oil is, more specifically, a polyolefin such as polybutene having a molecular weight of about 300 to 3500, Reacting with an acid to form monoalkenyl succinic anhydride,
Separately, amines selected from polyamines, such as ethylenediamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine and tetraethylenepentamine, and ammonium salts of boron oxide, boron halides, boronic acids, boronic esters and boronic acids. Reacting with a boron compound to obtain an intermediate,
This is synthesized by reacting with the above monoalkenylsuccinic anhydride and imidizing.
There are various alkenyl succinimide boron compound derivatives such as monoimide, diimide, and triimide. Details of the production method are described in JP-B-42-8013 and JP-B-42-8014.

[0009] The amount of the alkenyl succinimide boron compound derivative to be contained in the engine oil composition is, as described above, 0.1% based on the amount of boron derived from the boron compound.
0.01 to 0.1% by mass, and 0.01 to 0.08% by mass.
It is preferable that the content is contained, and more preferable content is 0.1.
It is from 0.01 to 0.04% by mass. If the addition amount is small, combustion products and heat deterioration products generated in the engine cannot be highly dispersed, while if it is too large, not only the addition effect corresponding to the addition amount cannot be obtained, but also the engine The effect of improving wear resistance in each part may not be high.

Component B to be added to the engine oil base oil of the present invention
That is, polysulfide is a compound represented by the following general formula (1).

[0011]

Embedded image

In the general formula (1), both R ¹ and R ² are a hydrocarbon group having 8 to 16 carbon atoms, which may be the same or different. Examples of hydrocarbon groups include
Examples thereof include an alkyl group, an alkenyl group, an aryl group, an aralkyl group, and a cycloalkyl group. An alkyl group is preferable, and an alkyl group having a tertiary carbon atom or a quaternary carbon atom is particularly preferable. Carbon number is 10-14
Is preferable. x is an integer of 2 to 7;
A range of 5 is preferred.

[0013] The content of polysulfide to be present in the engine oil is 0.2 to 3% by mass, and 0.3 to 3% by mass.
2.5% by weight is preferred. More preferred is 0.3
To 2% by mass, particularly preferably 0.3 to 1.5% by mass. If the content is small, the effect of improving the wear resistance inside the engine is small, and if it is too large, not only the addition effect corresponding to the addition amount can not be obtained, but it may also affect the bearing metal, exhaust gas purification catalyst, etc. There is.

Component B to be added to the engine oil base oil of the present invention
That is, thiadiazole or a derivative thereof is at least one compound represented by the following general formula (2).
This compound is described, for example, in US Pat.
No. 5, 2719126 can be produced by the production method disclosed in the specification.

[0015]

Embedded image

In the above general formula (2), R ³ and R
⁴ represents a linear or branched alkyl group having 1 to 12 carbon atoms. Specific examples include methyl, ethyl, propyl, butyl, hexyl, octyl groups and the like.

Preferred thiazole derivatives are those in which R ³ and R ⁴ in the general formula (2) are each a straight-chain or branched-chain alkyl group having 1 to 8 carbon atoms, and in particular, 2,5-bis ( tert-octyldithio)-
1,3,4-thiadiazole is preferred.

The amount of this component added is 0.0
The content is 1 to 2% by mass, and preferably 0.05 to 1.5% by mass. It is more preferably 0.1 to 1.3% by mass, and particularly preferably 0.1 to 1% by mass. If the addition amount is small, the effect of improving the corrosion resistance inside the engine is small. If the amount is too large, not only the effect corresponding to the added amount cannot be obtained, but also there is a possibility that satisfactory cleanliness cannot be obtained in each part of the engine.

When a mineral oil base oil is used as the base oil of the engine oil, for example, a mineral oil based lubricating oil fraction may be purified by solvent refining or hydrorefining, or an appropriate combination thereof. .

When a synthetic oil-based base oil is used, a synthetic oil-based lubricating oil such as α-olefin oligomer which is a polymer of α-olefin having 3 to 12 carbon atoms, sebacate including dioctyl sebacate, etc. Dialkyl diesters having 4 to 12 carbon atoms, such as azelate or adipate; polyol esters represented by esters obtained from 1-trimethylolpropane or pentaerythritol and a monobasic acid having 3 to 12 carbon atoms; And alkylbenzenes having an alkyl group of from 40 to 40.

Regardless of whether a mineral lubricating oil or a synthetic lubricating oil is used as the base oil, those selected from each group may be used alone or in combination of two or more. Alternatively, those selected from both groups may be mixed and used.

The viscosity of these base oils may be in the range of 0.1 to 250 mm ² / s at a kinematic viscosity of 40 ° C.
The preferred viscosity is 10 to 150 mm ² / s, particularly preferred viscosity is 20~120mm ² / s. The viscosity index is 5
What is necessary is just to be in the range of 0-200. Preferred is 80-
150.

The engine oil composition of the present invention may contain various known additives, if necessary, alone or in combination of two or more, in addition to the above-mentioned additives. Can be.

Examples of such additives include the following: Metal-based detergents such as alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, alkaline earth metal phosphonates and the like. Dispersants such as alkenyl succinimide, benzylamine and alkyl polyamine; various wear inhibitors such as phosphorus, sulfur, amine and ester; polymethacrylates such as polyalkyl methacrylate, ethylene propylene copolymer, styrene -Various viscosity index improvers such as isoprene copolymer, hydrogenated styrene-isoprene copolymer or polyisobutylene; alkylphenols such as 2,6-di-tert-butyl-p-cresol; 4,4'-methylenebis -(2,6-di-tert
Bisphenols such as -butylphenol), isononyl-3- (4'-hydroxy-3 ', 5'-di-te
rt-butylphenol) propionate, n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-tert
Various antioxidants such as phenolic compounds such as -butylphenol) propionate and aromatic amine compounds such as naphthylamines and dialkyldiphenylamines; sulfurized olefins, sulfurized oils and fats, methyltrichlorostearate, chlorinated naphthalene, iodinated benzyl, fluoroalkyl Extreme pressure agents such as polysiloxane and lead naphthenate; carboxylic acids such as stearic acid, dicarboxylic acids, metal soaps, amine salts of carboxylic acids, metal salts of heavy sulfonic acids, carboxylic acid partial esters of polyhydric alcohols, phosphorus Various rust inhibitors such as acid esters; various corrosion inhibitors such as benzotriazole and benzimidazole; and various antifoaming agents such as silicone oil.

The engine oil composition of the present invention may be prepared by appropriately mixing the base oil, the above-mentioned essential additives and various additives to be added as required. The mixing order is not particularly limited, and each essential component may be sequentially mixed with the base oil, or a pre-mixed essential component may be mixed with the base oil. The same applies to various additives to be arbitrarily added. The additives may be added to the base oil first, or may be added to the essential components and then blended into the base oil.

[0026]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples.

The base oils used for the production of the engine oil compositions of the examples and comparative examples, the types of the added essential components A to C and the additives, and the methods of the respective evaluation tests are as follows.

(Base oil and additives) Base oil A mineral oil having a viscosity at 40 ° C. of 35 mm ² / s and a viscosity index of 105. 2. Boron-containing succinimide A boron compound derivative of a bis-type polyalkenyl succinimide having a butenyl group having a molecular weight of about 2,000.
Stuff. The boron content in the alkenyl succinimide boron compound derivative is 0.7% by mass. 3. Polysulfide Di-tert-dodecyl polysulfide. In the comparative examples, sulfurized olefins or sulfurized oils and fats were used. 4. Thiadiazole 2,5-bis (tert-octyldithio) -1,3,4-
Thiadiazole. In the comparative example, benzotriazole was used. 5. A succinimide bis-type polyalkenyl succinimide,
The butenyl group has a molecular weight of about 2000.

(Evaluation Test) Metal Corrosion Test (Corrosion Resistance) A metal corrosion test was performed on a fresh engine oil composition (hereinafter, “new oil”) and a deteriorated engine oil composition (hereinafter, “deteriorated oil”). The deteriorated oil was prepared by deteriorating the new oil by a method (165.5 ° C., 72 hours) based on “Indiana Oxidation Stability Test” (JIS-K2514). Corrosion tests were performed on 30 new or degraded oils.
Put the following metal piece for corrosion test in a ml beaker.
Maintained at 50 ° C, Metal piece for corrosion test Metal type: LBC 3 (lead bronze casting) Chemical composition: Cu: 77.0-81.0 (%) Sn: 9.0-11.0 (%)
Pb: 9.0 to 11.0 (%) Shape: A disk with a diameter of 60 mm and a thickness of 1.0 mm is polished with sandpaper (# 400). After 360 hours, the amount of metal eluted in the oil is quantified by ICP analysis. Performed by The amount of Cu was evaluated for the new oil and the amount of Cu and Pb for the deteriorated oil, and the degree of corrosion was evaluated.

2. Wear Resistance Test The wear resistance of the valve train components was evaluated using a shell four-ball tester. The test conditions were a rotation speed of 1800 rpm, a test time of 20 seconds, and a constant oil temperature. The load was increased by 10 kg for the first time from 40 kg, and the wear scar diameter was 0.6.
The load above mm was recorded. The larger the load, the better the wear resistance.

[Examples 1 to 7] The above-mentioned base oil was prepared by adding a boron derivative compound of alkenyl succinimide (boron-containing succinimide), polysulfide, thiadiazole, and other additives such as a metal detergent, an antioxidant, An anti-wear agent and a viscosity index improver were blended at the ratio (mass%) shown in the upper part of Table 1 to prepare an engine oil composition. The lower part of Table 1 shows the evaluation results of the metal corrosion and wear resistance of the obtained engine oil composition. "Remainder" in the table means that the total amount of each component blended in the engine oil is 10%.
This means that the amount of the base oil was selected so as to be 0% by mass.

Table 1 Example 1 2 3 4 5 6 7 Base oil Remaining Remaining Remaining Remaining Remaining Remaining Remaining Remaining Boron-containing succinimide (% by mass) 5.0 3.0 10.0 5.0 5.0 5.0 5.0 5.0 Boron content 0.035 0.021 0.07 0.035 0.035 0.035 0.035 Thiadiazole ( (% By mass) 0.25 0.25 0.25 0.1 1.0 0.25 0.25 Polysulfide (% by mass) 1.0 1.0 1.0 1.0 1.0 0.5 2.0 Other additives * 11.0 11.0 11.0 11.0 11.0 11.0 11.0 Metal corrosion test result Cu in new oil (% by mass) 0.013 0.019 0.018 0.018 0.011 0.011 0.031 Cu in deteriorated oil (mass%) 0.0078 0.0085 0.0084 0.0098 0.0051 0.0068 0.015 Pb (mass%) in deteriorated oil 0.0011 0.0013 0.0012 0.0013 0.0009 0.0010 0.0018 Wear resistance evaluation result (kg) 160 160 160 160 160 150 160 * Other Additives include metal detergents, antioxidants, antiwear agents, and viscosity index improvers.

COMPARATIVE EXAMPLES 1-8 Boron-containing succinimide or succinimide, thiadiazo-
Metal, detergents, antioxidants, anti-wear agents,
The viscosity index improver was blended in the ratio (mass%) shown in the upper part of Table 2 to prepare an engine oil composition. The lower part of Table 2 shows the results of the metal corrosion evaluation and the wear resistance evaluation of the obtained engine oil composition.

Table 2 Comparative Example 1 2 3 4 5 6 Base Oil Remaining Remaining Remaining Remaining Remaining Remaining Remaining Boron-containing succinimide (% by mass) 5.0 5.0 5.0--5.0 Boron amount 0.035 0.035 0.035--0.035 Succinimide (% by mass) ) − − − 5.0 10.0 − Thiadiazole (% by mass) 0.25 0.25 0.25 0.25 0.25 − Benzotriazole (% by mass) − − − − − 0.25 Polysulfide (% by mass) − − − 1.0 1.0 1.0 Sulfurized olefin (% by mass) 1.0 − − − − − Sulfurized fat (% by mass) − 1.0 − − − − Other additives * 11.0 11.0 11.0 11.0 11.0 11.0 Metal corrosion test result Cu in new oil (% by mass) 0.38 0.15 0.018 0.023 0.025 0.035 Cu in deteriorated oil (% by mass) %) 0.65 0.28 0.0079 0.059 0.75 0.37 Pb in degraded oil (mass%) 0.013 0.011 0.0015 0.089 0.11 0.065 Abrasion resistance evaluation result (kg) 150 110 100 150 160 160 * Other additives are metal detergents and antioxidants , Anti-wear agent and viscosity index improver.

As is clear from the evaluation test data, the engine oil compositions of Examples 1 to 7 according to the present invention
All have excellent metal corrosion resistance and wear resistance. On the other hand, in the comparative example, both corrosion resistance and wear resistance could not be achieved.

[0036]

The engine oil composition of the present invention can achieve both excellent metal corrosion resistance and excellent abrasion resistance at a high level, and is extremely useful practically as an engine oil.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 30:06 30:12 40:25 60:14 (72) Inventor Toshio Koto 1134-2 Gongendo, Satte City, Saitama In the R & D Center of Sumo Research Institute (72) Inventor Haruhisa Yoshida 1134-2 Gongendo, Satte City, Saitama Prefecture In the R & D Center of Kosmo Research Institute, Inc.

Claims (1)

[Claims] An engine oil composition comprising an engine oil base oil selected from a mineral oil or a synthetic oil and the following components added thereto: (A) a boron compound derivative of an alkenyl succinimide is converted to a boron amount, 0.01 to 0.1% by mass, (B) 0.2 to 3% by mass of polysulfide, and (C) 0.01 to 2% by mass of at least one kind of alkylated thiadiazole or a derivative thereof.