WO2006115097A1 - Long-life fuel-saving engine oil composition - Google Patents

Abstract

A long-life fuel-saving engine oil composition which comprises a mineral and/or synthetic base oil; an amine antioxidant and a phenolic antioxidant added to the oil in a total amount of 1.2 mass% or larger in which the ratio of the mass amount of nitrogen (N) contained in the amine antioxidant to the mass amount of oxygen (O) contained in the phenolic antioxidant, (N/O), is 0.20-0.50; and MoDTC incorporated in an amount of 0.055 mass% or larger in terms of molybdenum amount. The long-life fuel-saving engine oil composition has excellent oxidative stability at high temperatures and retains low-frictional properties over long.

Description

 Specification

 Long-life fuel-saving engine oil composition

 Technical field

 TECHNICAL FIELD [0001] The present invention relates to a long-life fuel-saving engine oil that has excellent oxidation stability at high temperatures and low friction for a long time and has excellent high-temperature oxidation stability.

 Background art

 [0002] In recent years, to prevent global warming, improve the fuel efficiency of automobiles and reduce CO emissions

 2

 The demand is very high. Engine efficiency is important for improving automobile fuel efficiency, and lean burn and direct injection technologies are used in gasoline engines. On the other hand, reducing the friction of the engine can also contribute to improving fuel efficiency, so the use of low-friction materials for sliding parts and the use of fuel-saving engine oil are being promoted.

 [0003] In order to produce fuel-saving engine oil, the viscosity classification specified by SAE (American Automobile Engineering Association) J300 is 5W-20 and 0W-20. It is known that it is effective to add organic molybdenum FM such as molybdenum dithiocarnomate (MoDTC) as an additive to reduce (friction modifier, hereinafter also referred to as FM) (non-patent literature) 1).

 [0004] Because lean burn and direct injection engines are more efficient than conventional engines, combustion temperatures tend to rise, and pistons are exposed to higher temperatures. It is also necessary to improve the performance. In other words, future fuel-saving engine oils will require fuel-saving engine oils that are superior in terms of high-temperature acidity stability compared to conventional fuels, while MoDTC deteriorates with use and disappears from the oil. To go. For this reason, the fuel saving effect of MoDTC deteriorates with use, and improving the sustainability of this fuel saving effect is also an important issue.

 Patent Document 1: JP-A-10-17883

Non-Patent Document 1: K. Hoshino et al, FuelEfficiency of SAE 5W-20 Friction Modifired GasolineEngine Oil, SAE Technical Paper 982506 (1998) Disclosure of the invention

 Problems to be solved by the invention

 [0005] In view of the above situation, an object of the present invention is to provide an engine oil that is excellent in high-temperature oxidation stability and excellent in fuel-saving sustainability.

 Means for solving the problem

 [0006] As a result of diligent research to solve the above problems, the present inventor has blended mineral oil and Z or a synthetic base oil with a specific antioxidant in a specific ratio and has a certain ratio. It was found that the composition obtained by blending the above amount of MoDTC is useful as a long-life fuel-saving engine oil having good high-temperature oxidation stability. The present invention has been made on the basis of strong knowledge.

 [0007] That is, the present invention comprises a mineral oil and Z or a synthetic base oil containing 1.2% by mass or more of an amine-based anti-oxidation agent and a phenol-based anti-oxidation agent in total, and an amine The ratio (mass: N / O) of the nitrogen content (N) of the antioxidant and the oxygen content (O) of the phenolic antioxidant is 0.20 to 0.50, and molybdenum dithiocarbamate (MoDTC) Is an engine oil composition containing 0.055% by mass or more of molybdenum (Mo).

In particular, it contains a total of 1.5% by mass or more of amine-based anti-oxidants and phenol-based anti-oxidants, and the nitrogen content (N) of amine-based anti-oxidants and phenol-based anti-oxidants. the ratio of oxygen partial and (O) (weight: NZO) of agent is 0.20 to 0.35, it is preferable to further contain molybdenum Chio carbamate and (MoDTC) of molybdenum (Mo) 0.055 weight _^0/0 above. The invention's effect

 [0008] Since the long-life fuel-saving engine oil composition of the present invention has the above-described configuration, it has excellent high-temperature oxidation stability and low friction for a long period of time with little increase in viscosity even when used for a long period of time. It is a long-life, fuel-saving engine oil that has a special effect when sustained. Therefore, it can be suitably used for an internal combustion engine, in particular, a gasoline engine engine such as lean burn or direct injection, and exhibits an exceptional effect that fuel efficiency is improved and that it lasts for a long time.

BEST MODE FOR CARRYING OUT THE INVENTION [0009] The base oil used in the engine oil composition of the present invention can be any of mineral oil, synthetic base oil, and mixtures thereof. The kinematic viscosity at 100 ° C. is preferably 3.5 to 5.0 mm ² Zs, particularly 4.0 to 4.5 mm ² Zs. The viscosity index is preferably 110 to 160, particularly 120 to 140. For mineral oil, a high viscosity index lubricating base oil having a viscosity index of 120 or higher is desirable. Viscosity index Strength S 120 or higher high viscosity index lubricant base oil is obtained by solvent dewaxing or hydrodewaxing the oil obtained by hydroisomerization of wax hydroisomer or heavy oil. be able to. One example of these production methods will be described more specifically below.

[0010] Hydroisomerization of wax is performed by using a wax having a boiling range power of S300 to 600 ° C and a carbon number in the range of 20 to 70, such as slack wax obtained in a solvent dewaxing process of mineral oil-based lubricating oil, carbonization Hydrogen gas isometric force also synthesizes liquid fuel Fischer-Tropsch synthesis using wax, etc. as raw materials, hydroisomerization catalyst, for example, alumina or silica alumina Group 8 metals such as nickel and cobalt on a support, molybdenum, tungsten A catalyst carrying one or more of group 6A metals such as zeolite catalyst, zeolite catalyst or catalyst containing platinum supported on a zeolite-containing support, and a hydrogen partial pressure of 5-14 MPa in the presence of hydrogen at a temperature of 300-450 ° C. it can be carried out by contacting at LHSV of 0.1~2hr ^_1 (liquid hourly space velocity). At this time, it is preferable that the conversion rate of the linear paraffin is 80% or more and the conversion rate to the light fraction is 40% or less.

On the other hand, hydrocracking involves hydrocracking atmospheric distillate, vacuum distillate or bright stock having a boiling point in the range of 300 to 600 ° C. that has been hydrodesulfurized and denitrogenated as required. A catalyst, for example, a catalyst in which one or more group 8 metals such as nickel and cobalt and one or more group 6A metals such as molybdenum and tungsten are supported on a silica alumina support, and a hydrogen partial pressure of 7 to 14 MPa. In the presence of hydrogen, it can be carried out in contact with LHSV (liquid space velocity) at a temperature of 350 to 450 ° C and 0.1 to 2 hr ^_1 , and the decomposition rate (reduced quality of the fraction above 360 ° C in the product) Amount / ₀ ) It is preferable to make the force 0-90%.

[0012] A light oil fraction can be distilled from the hydroisomerized product oil or hydrocracked product oil obtained by the above-mentioned method to obtain a lubricating oil fraction. Since the viscosity is high and the viscosity index is not sufficiently high, dewaxing is performed to remove the wax component, and the% C force by nd M ring analysis is ¾0 or more, and the pour point is 10 ° C or less. A lubricant base oil having a force S i of 20 or more can be obtained.

 [0013] When this wax content is removed by solvent dewaxing, the light fraction is distilled off using a precision distillation apparatus, and has a boiling point of 371 ° C or higher by gas chromatography distillation in advance. It is preferable to cut so that the fraction less than 70 ° C. is 70% by mass or more in order to perform the solvent dewaxing treatment more efficiently. This solvent dewaxing treatment is carried out using, for example, methyl ethyl ketone Ztoluene (volume ratio 1Z1) as a dewaxing solvent and in a solvent / oil ratio range of 2Z1 to 4Zl at a temperature of 15 to 40 ° C. Good.

[0014] On the other hand, when the wax content is removed by the hydrodewaxing method, the distillation of the light fraction should be such that it does not hinder hydrodewaxing, and after hydrodewaxing, a precision distillation apparatus is used. It is efficient and preferable that the fraction having a boiling point of 371 ° C or more and less than 491 ° C is 70% by mass or more by distillation separation and gas chromatography distillation. This hydrodewaxing is carried out by contacting the zeolite catalyst with the LHSV (liquid space velocity) of 0.2 to 4 hr ^{_1 in} the presence of hydrogen at a hydrogen partial pressure of 3 to 15 MPa at a temperature of 320 to 430 ° C and the final lubricating oil. Make the pour point in the base oil less than-10 ° C! /.

 [0015] The ability to obtain a lubricating base oil having a viscosity index of 120 or higher by the above method can be further subjected to solvent refining or hydrorefining as desired.

 [0016] Synthetic oils include a-olefin oligomers, diesters synthesized from dibasic acids such as adipic acid and monohydric alcohols, and polyhydric alcohols such as neopentyl glycol, trimethylol propan bread and pentaerythritol. Examples thereof include polyol esters that are also synthesized with monobasic acid and power, and mixtures thereof.

 Furthermore, mixed oils combining appropriate mineral oils and synthetic oils can also be used as base oils for this engine oil!

 [0017] MoDTC used in the engine oil of the present invention is represented by the following general formula (1).

 [Chemical 1]

式中、 I^〜R⁴は、炭素数 4〜18個を有する直鎖及び Z又は分岐のアルキル基及び Z又はアルケニル基を表し、 Xは酸素原子又は硫黄原子を表し、その酸素原子と硫 黄原子との比は 1Z3〜3Z1である。 I^〜R⁴は、好ましくはアルキル基であり、特に 好ましくは炭素数 8〜 14の分岐のアルキル基であり、具体的にはブチル基、 2—ェチ ルへキシル基、イソトリデシル基、ステアリル基等が挙げられる。 1分子中に存在する 4個の I^〜R⁴は、同一であってもよぐ異なっていてもよい。また、 R¹〜R⁴の異なるM oDTCを 2種以上混合して用いることもできる。

In the formula, I ^ to R ⁴ represent a linear and Z or branched alkyl group having 4 to 18 carbon atoms and a Z or alkenyl group, X represents an oxygen atom or a sulfur atom, and the oxygen atom and sulfur The ratio with yellow atoms is 1Z3 ~ 3Z1. I ^ to R ⁴ are preferably alkyl groups, particularly preferably branched alkyl groups having 8 to 14 carbon atoms, and specifically include butyl, 2-ethylhexyl, isotridecyl, stearyl. Groups and the like. The four I ^ to R ⁴ present in one molecule may be the same or different. Also, two or more kinds of MoDTCs having different R ^{1 to} R ⁴ can be mixed and used.

 The MoDTC content is 0.055% by mass or more, especially 0.055 to 0.12% by mass, and 0.06 to 0. 10% by mass is preferred.

 As the anti-oxidation agent used in the engine oil of the present invention, both a phenol-based anti-oxidation agent and an amine-based anti-oxidation agent are used.

 As the phenolic acid / antioxidant suitable for use in the engine oil of the present invention, a phenolic compound having an acidity-preventing ability and having a substituent containing an ester bond can be used. Specific examples include compounds represented by the following general formulas (2) and (3).

 [Chemical 2]

式（2)において、 R⁵は、炭素数が 3以上 20以下の炭化水素基が好ましぐ特に好ま L ヽ炭化水素基としてはォクチル基、ステアリル基が挙げられる。

In the formula (2), R ⁵ is preferably a hydrocarbon group having 3 to 20 carbon atoms. The L L hydrocarbon group includes an octyl group and a stearyl group.

本発明のエンジン油に好適に使用されるァミン系酸ィ匕防止剤としては、酸ィ匕防止 能を有するジフヱ-ルァミン及び Zまたはフエ-ルナフチルァミンが好ましぐ具体的 には、下記の一般式 (4)及び（5)で表される化合物が挙げられる。 [Chemical 3]

Specific examples of the amine-based acid / antioxidant suitable for use in the engine oil of the present invention are diph-lamine and Z or fernaphthylamine which have acid-deterrent-preventing ability. Examples include compounds represented by (4) and (5).

[Chemical 4]

式 (4)の化合物は、一般的には、 N—フエ-ルベンゼンァミンとアルケンとを反応さ せて得られる化合物である。式 (4)において、 R⁶、 R⁷は、炭化水素基であり、各ベン ゼン環で 5個ずつ、合計 10個置換しえる力 少なくとも 1個以上置換しているものが 好ましい。炭化水素基の炭素数は 3以上 20以下が好ましぐ R⁶と R⁷の合計が複数の 場合、それぞれは同じ炭化水素基であっても異なっていてもよい。より好ましくは、ブ チル基力 ノ-ル基までの直鎖又は分枝鎖のアルキル基が挙げられる。

The compound of formula (4) is generally a compound obtained by reacting N-phenylbenzeneamine with an alkene. In the formula (4), R ⁶ and R ⁷ are hydrocarbon groups, and it is preferable that at least one or more is substituted with a force capable of substituting five in each benzene ring, for a total of ten. The number of carbon atoms of the hydrocarbon group is preferably 3 or more and 20 or less. When there are a plurality of R ⁶ and R ⁷ in total, each may be the same hydrocarbon group or different. More preferred is a linear or branched alkyl group up to a butyl group-nor group.

[Chemical 5]

式（5)において、 R⁸〜R⁹は、炭素数が 3以上 20以下の炭化水素基であり、式（5) にはナフチル基及びフエ-ル基の両方に置換されて 、るように記して 、るが、少なく ともどちらか一方の基に 1個以上置換されているものでも、両方の基にそれぞれ 1個 ずつ以上置換されているものでもよい。 R⁸〜R⁹がそれぞれ複数個の場合、それぞれ は同一であっても、異なっていてもよい。なお、 R⁸〜R⁹は炭素数が 6以上 12以下の アルキル基が好ましぐ直鎖又は分枝鎖のォクチル基ないしノ-ル基で、ナフチル基 又はフエ-ル基のどちらか一方に 1個置換されているものが特に好ましい。

In the formula (5), R ^{8 to} R ⁹ are hydrocarbon groups having 3 to 20 carbon atoms, and in the formula (5), both naphthyl groups and phenyl groups are substituted. Write, but less In either case, one group may be substituted by one or more groups, or both groups may be substituted by one group or more. When there are a plurality of R ^{8 to} R ⁹ , each may be the same or different. R ^{8 to} R ⁹ are linear or branched octyl groups or nor groups, preferably an alkyl group having 6 to 12 carbon atoms, and either a naphthyl group or a phenyl group. Particularly preferred is one substituted.

 In addition, as the amine-based antioxidant, compounds represented by the general formulas (4) and (5) can be mixed and used.

 [0022] The total content of the phenolic acid antioxidant and the amine acid antioxidant is 1.5% by mass or more, and the nitrogen content (N) of the amine antioxidant and phenolic acid oxidation prevention. It is preferable to blend so that the mass ratio (NZO) of oxygen content (O) of the agent is 0.20 to 0.35, particularly 0.25 to 0.30. The total content of the antioxidants is preferably 1.5% by mass or more, particularly preferably 1.5 to 3% by mass. If this sum is less than 1.5% by mass, the target high-temperature oxidation stability cannot be obtained, for example, the viscosity increase rate of Sequence III G test is 150% or less, especially 0-100%. Also, if the ratio of the nitrogen content of the amine-based anti-oxidation agent to the oxygen mass of the phenol-based anti-oxidation agent is less than 0.20, the target high-temperature oxidation stability cannot be obtained. On the other hand, if the ratio of the nitrogen content of the amine-based anti-oxidation agent to the oxygen content of the phenol-based anti-oxidation agent exceeds 0.35, the low friction life by the target MoDTC cannot be obtained.

 [0023] In the engine oil of the present invention, if desired, detergents such as zinc alkyldithiophosphate (ZnDTP), Ca, Mg, Ba, Na, sulfonates, phenates, salicylates, alkenyl succinimides, etc. Additives such as ashless dispersants, other viscosity index improvers, pour point depressants, metal deactivators, antifungal agents and antifoaming agents can be added.

 Example

 Next, the present invention will be specifically described with reference to examples.

The base oil is a mineral base oil (kinematic viscosity: 20.3mm ² Zs (40 ° C), 4.34mm ² ) obtained by hydrodewaxing the product oil obtained by hydrocracking heavy oil. Zs (100 ° C) and viscosity index 124) were used.

[0025] In the base oil, phenolic acid antifouling agent A, which is described below as an additive, and amine acid The engine oils of Example 1 and Comparative Examples 1 to 3 were prepared by blending the inhibitor B, MoDTC and other additives in the proportions shown in Table 1. Table 1 also shows the ratio (mass: NZO) of the nitrogen content (N) of the added amine-based antioxidant and the oxygen content (O) of the phenol-based antioxidant and the Mo content. . The other additive is an additive mixture composed of zinc alkyldithiophosphate (ZnDTP), Ca sulfonate, alkenyl succinimide, viscosity index improver, pour point depressant and antifoaming agent. In all cases, the same amount was added.

[0026] Phenolic antioxidant A: A phenolic antioxidant (oxygen content 12.3% by mass) represented by the general formula (2), in which the substituent R ⁵ is an octyl group was used.

 Amine-based oxidizing agent B: An amine-based antioxidant (nitrogen content: 4.5% by mass), which is a reaction product of N-phenylbenzeneamine and 2,4,4-trimethylpentene, was used.

MoDTC: A compound represented by the general formula (1) in which I ^ to R ⁴ are a mixture of 2-ethylhexyl group and isotridecyl group and the ratio of oxygen atom to sulfur atom is lZi.

 [0027] [Table 1]

表 1の実施例及び比較例のエンジン油それぞれについて、 Sequence III G試験を 実施して、エンジン油性能を評価した。その中に高温酸ィ匕安定性を粘度増加率で評 価する項目があり、合格基準として粘度増加率 150%以下が規定されている (鈴木、 ガソリンエンジン油規格の最新動向、月刊トライボロジ一、 2003. 5、 17頁参照)。上 記それぞれの供試エンジン油について、 Sequence III G試験に従ってエンジン試験 1 00時間後のエンジン油をエンジン試験開始時 (0時間）のエンジン油と比較して粘度 増加率を求めた。その結果を表 2に示す

A sequence III G test was conducted for each of the engine oils of the examples and comparative examples in Table 1 to evaluate the engine oil performance. Among them, there is an item that evaluates the stability of high-temperature acid and soot by the rate of increase in viscosity, and a viscosity increase rate of 150% or less is specified as a passing standard (Suzuki, latest trends in gasoline engine oil standards, monthly tribology, 2003.5, page 17). Up For each test engine oil, the rate of increase in viscosity was determined by comparing the engine oil after 100 hours of engine test with the engine oil at the start of engine test (0 hour) according to Sequence III G test. The results are shown in Table 2

[0029] Furthermore, for each of the engine oils in Table 1, the engine test, which is a bench durability test, and the SRV friction test to measure friction were conducted under the following conditions, and the friction coefficient of the engine oil was reduced to 0.070. And the sustainability of fuel efficiency was evaluated in comparison with standard oil (test time of 165 hours with a friction coefficient of 0.070, mileage equivalent to this time of 10,000 km). The results are shown in the lower part of Table 2 as the low friction durability life (km).

[0030] Engine test conditions

 • Engine: 2L inline 6-cylinder gasoline engine

 • Oil pan capacity: 3.4L reduced to 2L (test severity was accelerated)

 • Oil pan oil temperature: 100 ° C

 • Test mode: AMA driving mode (repeated)

 • Oil sampling: Every 24 hours (sample for SRV friction test)

[0031] SRV scrub test conditions

 'Contact conditions: Cylinder on block

 'Sliding conditions: Load 400N, frequency 50Hz, amplitude 1.5mm, temperature 120 ° C

 The test time until the friction coefficient of engine oil reached 0.070 was obtained by interpolating the sampling time of two samples with a friction coefficient of 0.070 between samples sampled every 24 hours (used engine oil). Based on the test time until the friction coefficient obtained is 0.070, and the test time (165 hours) and the mileage 10,000 km until the friction coefficient of the standard oil is 0.070, the low friction durability (travel distance, km )

[0032] [Table 2]

[0033] As is clear from the above results, the mineral oil and Z or synthetic base oil shown in the Examples The total addition amount of the amine acid inhibitor and the phenol acid inhibitor is 1.5% by mass or more, and the nitrogen mass (N) of the amine acid inhibitor and the phenol acid inhibitor The ratio (NZO) of the oxygen mass (O) of the engine oil composition is 0.20 to 0.35, and MoDTC is mixed in an Mo content of 0.055% by mass or more. A good high-temperature acidity stability is expected. In addition, the MoDTC low friction durability life calculated from the SRV friction test force of the oil used in the engine durability test is 9000km or more, indicating that it has excellent fuel economy and sustainability.

 On the other hand, the engine oil composition of Comparative Example 1 containing only the phenolic acid antioxidant has a long low friction life, but has a very large viscosity increase rate and is inferior in high-temperature acidity stability. In addition, Comparative Example 2, which has a high ratio of nitrogen content of amine-based acid repellant and oxygen content of phenol-based repellency inhibitor, is excellent in oxidation stability but inferior in low friction life. Further, it can be seen that Comparative Example 3 in which the blending amount of MoDTC is reduced is larger in viscosity increase rate and inferior in high-temperature oxidation stability than in Example 1, and inferior in low friction life.

Claims

The scope of the claims  [1] Mineral oil, Z, or synthetic base oil contains 1.2% by mass or more of amine-based acid antioxidant and phenolic acid-acid inhibitor in total, and nitrogen of amine-based acid antioxidant The ratio (mass: NZO) of the component (N) to the oxygen content (O) of the phenol-based antioxidation agent is 0.20 to 0.50, and molybdenum dicarbamate (MoDTC) is 0.055 mass in molybdenum (Mo). A long-life fuel-saving engine oil composition characterized by containing at least%. [2] The ratio (mass: NZO) between the nitrogen content (N) of the amine antioxidant and the oxygen content (O) of the phenolic acid antioxidant is 0.20 to 0.35. Item 1. A long-life fuel-saving engine oil composition according to item 1.  [3] Containing 1.5% by mass or more of the amine-based acid antioxidant and the phenol-based acid antioxidant, and the nitrogen content (N) of the amine-based acid antioxidant and the phenol-based acid solvent. The ratio (mass: NZO) to the oxygen content (O) of the inhibitor is 0.20 to 0.35, and molybdenum dithiocarbamate (Mo DTC) is contained in molybdenum (Mo) in an amount of 0.055% by mass or more. The long-life fuel-saving engine oil composition as described in 1.  [4] The amine antioxidant is diphenylamine and Z or phenolnaphthylamine, and the phenolic acid antioxidant is a phenolic compound having a substituent containing an ester bond. Item 1. A long-life fuel-saving engine oil composition according to Item 1.