JP2000345182A - Lubricant composition for cellulose-based wet friction material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant composition, improved in exfoliation-durability of friction materials, in particular cellulose-based wet friction materials, without damaging its resistance to wear and scoring. SOLUTION: This lubricant composition for cellulose-based wet friction materials comprises a base oil incorporated with (A) a boron-containing imide- based dispersant having a weight-average molecular weight of 500 to 3,000 and boron/nitrogen(B/N) wt. ratio of 0.1 to 1.5, in such a way to keep contents of the boron and nitrogen derived from the component A at 60 wt.ppm or more and 100 wt.ppm or more, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating oil composition for a cellulosic wet friction material, and more particularly, to the separation of a friction material, particularly a cellulosic wet friction material, without impairing abrasion resistance and scoring resistance. The present invention relates to a lubricating oil composition which improves durability and is suitable for use as a starting device and a transmission clutch friction material made of cellulose for use in an automatic transmission of an automobile.

[0002]

2. Description of the Related Art In recent years, for example, a conventional automatic transmission, a belt drive continuously variable transmission, a traction drive continuously variable transmission, and the like have been used as automobile transmissions. With the diversification of machines, the characteristics required for transmission oils are also changing. In the above belt drive continuously variable transmission and traction drive continuously variable transmission, in addition to mounting the starting device and the lock-up clutch, the belt drive or the traction drive portion is a new lubrication element. Also,
Recently, transmissions have been reduced in size, weight, and transmission capacity, and the lubricating oil used in such transmissions has high friction properties such as gears, bearings, belt drive units and traction drive units. Lubrication characteristics for the surface pressure lubricated portion, for example, anti-wear properties, scoring (seizure) prevention properties, etc. are required. As described above, the lubricating oil used in the transmission for automobiles is required to have abrasion resistance and scoring resistance at the same time as being provided with the frictional properties with respect to the friction material (wet clutch). Higher additives tend to be used.

However, an additive having a high reactivity to a metal surface, that is, an active additive, has a high reactivity to cellulose, which is a main component of a friction material, and breaks the cellulose structure (such as cutting a chain-cellulose fiber). This has the drawback of causing elution into oil and causing damage such as peeling of friction material. Therefore, without impairing the wear resistance and scoring resistance of the transmission oil,
There has been a demand for the development of a technique capable of reducing or suppressing the aggressiveness (reactivity) to cellulose, which causes the separation of the friction material. However, there have been few reports on techniques for reducing or suppressing the peeling damage of such friction materials, and only the effect of a metal-based detergent / dispersant (calcium sulfonate having a total base number of 300) has been reported. ["Automotive Technology Society, Academic Lectures Preprints" 952, 953529
7, 1995-5]. In addition, when this metal-based detergent / dispersant is blended, there arises a problem that pores on the surface of the friction material are clogged and the friction characteristics may be reduced.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to improve the peeling durability of a friction material, especially a cellulosic wet friction material, without impairing abrasion resistance and scoring resistance in such a situation. It is an object of the present invention to provide a lubricating oil composition suitable for use as a starting device and a transmission clutch friction material made of cellulose for use in automatic transmissions.

[0005]

The present inventors have conducted intensive studies to develop a lubricating oil composition having excellent performance as described above. As a result, a specific boron-containing imide dispersant was added to the base oil. It has been found that the object can be achieved by blending so that the boron content and the nitrogen content in the composition are equal to or more than predetermined values. The present invention has been completed based on such findings. That is, according to the present invention, (A) the weight average molecular weight is 500 to 3000,
And a boron-containing imide dispersant having a weight ratio (B / N) of boron to nitrogen of 0.1 to 1.5, wherein the boron content and the nitrogen content derived from the component (A) in the composition are as follows: 60 each
An object of the present invention is to provide a lubricating oil composition for a cellulose-based wet friction material, which is blended so as to be not less than 100 ppm by weight and not more than 100 ppm by weight.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The base oil used in the lubricating oil composition of the present invention is not particularly limited, and those conventionally used as base oils for lubricating oils for automatic transmissions of automobiles have been used.
For example, the following mineral oils and synthetic oils are used. Mineral oils include, for example, 60 neutral oils, 100 neutral oils, 150 neutral oils by solvent refining or hydrogen refining,
Examples include 300 neutral oil, 500 neutral oil, and a low pour point base oil in which low-temperature fluidity is improved by removing a wax component from these base oils. These may be used alone, or two or more kinds may be used at an appropriate ratio. May be used as a mixture. On the other hand, as the synthetic oil, for example, synthetic naphthenic oil,
Poly-α-olefin oligomers, further diesters,
Ester oils such as polyol esters and polyglycol esters are exemplified. These base oils are usually used alone, but can be used in combination with the mineral oil. This base oil has a content in the lubricating oil composition of usually 80%.
It is used so that it may become more than weight%.

In the lubricating oil composition of the present invention, (A)
As the boron-containing imide-based dispersant, those having a weight average molecular weight of 500 to 3000 and a weight ratio (B / N) of boron to nitrogen in the range of 0.1 to 1.5 are used. If the weight average molecular weight deviates from the above range or the B / N ratio deviates from the above range, a lubricating oil composition having desired performance cannot be obtained, and the object of the present invention cannot be achieved.
From the viewpoint of the performance of the lubricating oil composition, the boron-containing imide-based dispersant has a weight average molecular weight in the range of 700 to 2500 and a B / N ratio in the range of 0.2 to 1.0. Is preferred. The boron-containing imide-based dispersant of the component (A) is not particularly limited as long as it has the above-mentioned properties, and is appropriately selected from those conventionally used as additives for lubricating oils. Can be used. As the boron-containing imide dispersant, for example, a compound represented by the general formula (I)

[0008]

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A monopolyalkenyl or polyalkylsuccinimide represented by the general formula (II):

[0010]

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The bispolyalkenyl or poly represented by the formula
Lialkyl succinimide treated with boron compound
And the like. The above general formulas (I) and (II)
And R¹, R^ThreeAnd R^FourAre each having 2 to 8 carbon atoms
Degree of α-olefin oligomer residue or its hydrogenation
Object, R^ThreeAnd R^FourEven though they are the same, they are different
May be. Also, R^Two, R^FiveAnd R ⁶Are each charcoal
An alkylene group having a prime number of 2 to 4,^FiveAnd R⁶Hate
They may be the same or different. m is an integer from 1 to 10
The number and n are 0 or an integer of 1 to 10. In the present invention
Is a boron-containing imide-based dispersant (A)
Using a mono-treated borane product represented by the general formula (I)
And the boron treatment of the bis-form represented by the general formula (II)
Or a mixture of these.
No.

The polyalkenyl or polyalkylsuccinimide represented by the general formulas (I) and (II) is usually a polyalkenyl succinic anhydride or a hydride thereof obtained by reacting a polyolefin with maleic anhydride. It can be produced by reacting a polyalkylsuccinic anhydride with a polyalkylenepolyamine.
The mono- and bis-forms of the above-mentioned polyalkenyl or polyalkylsuccinimide can be produced by changing the reaction ratio between polyalkenyl or polyalkylsuccinic anhydride and polyalkylenepolyamine. In the production of the polyalkenyl or polyalkyl succinimide, the polyolefin used as a raw material is selected from those obtained by polymerizing an α-olefin having about 2 to 8 carbon atoms. The weight average molecular weight of the dispersant is 500 to 30
It is appropriately selected and used so as to be in the range of 00. The α-olefin forming the polyolefin may be used alone or in combination of two or more. As this polyolefin, polybutene is particularly preferred. On the other hand, examples of the polyalkylene polyamine include polyethylene polyamine, polypropylene polyamine,
Polybutylene polyamine and the like can be mentioned, and among them, polyethylene polyamine is preferable.

The polyalkenyl or polyalkyl succinimide is preferably a polyalkenyl succinimide, and more preferably a polybutenyl succinimide having a weight average molecular weight of about 500 to 3,000. In the lubricating oil composition of the present invention, the boron-containing imide-based dispersant of the component (A) is added to the base oil with the component (A) in the composition.
The boron content and the nitrogen content derived from the components are 6
It is necessary to mix them so as to be 0 ppm by weight or more and 100 ppm by weight or more. The boron content is less than 60 ppm by weight, or the nitrogen content is 100 ppm by weight.
If the value is less than the above, the aggressiveness of the active phosphorus compound or the active sulfur compound to the cellulose friction material (cutting of the cellulose chain by the reaction between the cellulose and the active phosphorus compound or the active sulfur compound, promotion of dissolution) is alleviated, It cannot be suppressed, and surface damage such as peeling of the friction material easily occurs at an early stage. From the viewpoint of effectively suppressing surface damage of the friction material and economical efficiency, the boron content is preferably 60 to
500 weight ppm, more preferably 60-300 weight p
pm, while the nitrogen content is preferably between 100 and 2000 ppm by weight, more preferably between 100 and 2000 ppm by weight.
It is in the range of 1200 ppm by weight.

In the lubricating oil composition of the present invention,
As the component (B), at least one selected from active phosphorus compounds and active sulfur compounds is blended. The active phosphorus compound is not particularly limited, and is a known active phosphorus compound conventionally used as an extreme pressure agent, an antiwear agent, a friction modifier, and the like, for example, an acidic phosphoric acid ester,
It can be appropriately selected from phosphites, acidic phosphites, hypophosphites and the like according to the situation. In the present invention, examples of the active phosphorus compound include compounds represented by general formula (III):

[0015]

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The acidic phosphoric acid esters and / or phosphites represented by the formula (1) are preferably used. In the above general formula (III), A represents a hydrogen atom or a hydroxyl group, k represents 0 or 1, and when k is 0, A is a hydroxyl group, and when k is 1, A is a hydrogen atom or a hydroxyl group. R ⁷ and R ⁸ each represents a hydrogen atom or one or more oxygen atoms and / or a hydrocarbon group having 1 to 18 carbon atoms which may contain a sulfur atom. Here, the hydrocarbon group having 1 to 18 carbon atoms includes a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, and a linear chain having 2 to 18 carbon atoms. Alternatively, a branched alkenyl group, an aryl group having 6 to 18 carbon atoms, or an aralkyl group having 7 to 18 carbon atoms may be used. Examples of the alkyl group having 1 to 18 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n
-Butyl group, isobutyl group, sec-butyl group, ter
t-butyl group, pentyl group, hexyl group, octyl group,
2-ethylhexyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group. An octadecyl group; Examples of the cycloalkyl group having 3 to 18 carbon atoms include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, and a cyclooctyl group. Examples of the alkenyl group having 2 to 18 carbon atoms include an allyl group,
Examples include a propenyl group, a butenyl group, an octenyl group, a decenyl group, and an oleyl group. Examples of the aryl group having 6 to 18 carbon atoms include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. Examples of the aralkyl group having 7 to 18 carbon atoms include a benzyl group, a phenethyl group, and a naphthylmethyl group. And the like.

Further, the hydrocarbon group having 1 to 18 carbon atoms may contain one or more oxygen atoms and / or sulfur atoms. That is, the main chain may contain one or more ether groups and / or thioether groups. Examples of such hydrocarbon groups include hexyloxymethyl, hexyloxyethyl, octyloxymethyl, octyloxyethyl, dodecyloxymethyl, dodecyloxyethyl, hexadecyloxymethyl, and hexadecyloxy. Ethyl, hexylthiomethyl, hexylthioethyl, octylthiomethyl, octylthioethyl, dodecylthiomethyl, dodecylthioethyl, hexadecylthiomethyl, hexadecylthioethyl, and the like. R ⁷ and R ⁸ may be the same or different, but neither R ⁷ nor R ⁸ is a hydrogen atom.
Among the compounds represented by the general formula (III), examples of the acidic phosphoric acid ester include a compound represented by the general formula (III-a)

[0018]

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(R ⁷ and R ⁸ in the formula are the same as described above). Examples of the acidic phosphate represented by the general formula (III-a) include mono- or di-hexyl hydrogen phosphate, mono- or di-octyl hydrogen phosphate, mono- or di-dodecyl hydrogen phosphate, mono- or di-dodecyl hydrogen phosphate, Di-hexadecyl hydrogen phosphate, mono- or di- (hexylthioethyl) hydrogen phosphate, mono- or di- (octylthioethyl) hydrogen phosphate, mono- or di- (dodecylthioethyl) hydrogen phosphate, mono- or di- -(Hexadecylthioethyl) hydrogen phosphate, mono- or di-octenyl hydrogen phosphate, mono- or di-oleyl hydrogen phosphate, mono- or di-cyclohexyl hydrogen phosphate, mono Or di-phenyl hydrogen phosphate, mono- or di-tolyl hydrogen phosphate, mono- or di-benzyl hydrogen phosphate, mono- or di-phenethyl hydrogen phosphate, and the like. Among the compounds represented by the general formula (III), the phosphite is represented by the general formula (III
-B) or the general formula (III-c)

[0020]

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(Wherein R ⁷ and R ⁸ are the same as described above). This general formula (III-b) or general formula (III-c)
Examples of the acidic phosphite represented by are mono- or di-hexyl hydrogen phosphite, mono- or di-octyl hydrogen phosphite, mono- or di-
Dodecyl hydrogen phosphite, mono- or di-hexadecyl hydrogen phosphite, mono- or di-
(Hexylthioethyl) hydrogen phosphite,
Mono- or di- (octylthioethyl) hydrogen phosphite, mono- or di- (dodecylthioethyl) hydrogen phosphite, mono- or di- (hexadecylthioethyl) hydrogen phosphite, mono- or di-octenyl hydrogen Gen phosphite, mono or di-oleyl hydrogen phosphite, mono or di
Cyclohexyl hydrogen phosphite, mono- or di-phenyl hydrogen phosphite, mono- or di-toluyl hydrogen phosphite, mono- or di-
Benzyl hydrogen phosphite, mono- or di-phenethyl hydrogen phosphite and the like can be mentioned.

On the other hand, the active sulfur compound is not particularly limited, and is a known active sulfur compound conventionally used as an extreme pressure agent, an antiwear agent, a friction modifier or the like, for example, a sulfide of animal or vegetable oil or synthetic oil. Sulfurized oils, olefin mono- or polysulfides, dihydrocarbyl mono- or polysulfides, sulfurized mineral oils, thiocarbamates, thioterpenes, dialkylthiodipropionates, etc. Here, examples of sulfurized oils and fats include sulfurized lard, sulfurized rapeseed oil, sulfurized castor oil, sulfurized soybean oil,
Examples thereof include sulfurized rice bran oil, disulfide fatty acids such as sulfurized oleic acid, and sulfurized esters such as sulfurized methyl oleate. Examples of the olefin mono- or polysulfide include olefins having 3 to 20 carbon atoms or 2 to 4 olefins thereof.
And those obtained by reacting the monomer with a sulfurizing agent, specifically, sulfur, sulfur chloride, other sulfur halides, and the like.
As the olefin, for example, propylene, isobutene, diisobutene and the like are preferable.

The dihydrocarbyl mono- or polysulfide is represented by the general formula (IV) R ⁹ -S _x -R ¹⁰ ... (IV) (wherein R ⁹ and R ¹⁰ are alkyl having 1 to 20 carbon atoms, respectively) Group, aryl group having 6 to 20 carbon atoms, 7 to 2 carbon atoms
0 represents an alkylaryl group or an aralkyl group having 7 to 20 carbon atoms, which may be the same or different, and x represents a real number of 1 to 8 (specifically, a rational number). ). R ⁹ in the above general formula (IV)
And R ¹⁰ include a methyl group, an ethyl group, n-
Propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various dodecyl Group, cyclohexyl group, cyclooctyl group, phenyl group, naphthyl group, tolyl group, xylyl group, benzyl group, phenethyl group and the like. Preferred examples of the dihydrocarbyl mono- or polysulfide include dibenzyl mono- or polysulfide, di-t-nonyl mono- or polysulfide, didodecyl mono- or polysulfide, and the like. Further, as thiocarbamates, for example, zinc dithiocarbamate, etc., as thioterpenes, for example, a reaction product of phosphorus pentasulfide and pinene, and as dialkylthiodipropionates, for example, dilauryl thiodipropionate, And stearyl thiodipropionate.

In the present invention, the active phosphorus compound or active sulfur compound of the component (B) may be used alone.
Two or more kinds may be used in combination. The compounding amount is not particularly limited as long as it is an amount commonly used in lubricating oils for automobile transmissions. When an active phosphorus compound is used as the component (B), if necessary, the active phosphorus compound is mixed with the boron-containing imide-based dispersant of the component (A) in advance, and then the mixture is mixed with an active phosphorus compound. 150 ° C
Heat treatment is performed at a temperature of about 5 hours or more, and this heat-treated product can be blended with the base oil. In this case, the component (A) to be blended and a part of the active phosphorus compound are mixed and heated, and the heat-treated product and the remaining component (A) or the active phosphorus compound are blended into a base oil. Alternatively, the total amount of the component (A) to be blended and the active phosphorus compound may be mixed and heat-treated, and the heat-treated product may be blended with the base oil. As a specific method of this heat treatment, first, the component (A) and the active phosphorus compound are mixed at a predetermined ratio,
The mixture is stirred at a temperature of about 0 ° C. for about 10 minutes to 3 hours to perform a homogenization treatment. Next, the homogenized product is heated to 120 to 150 ° C.
The heat treatment is performed at a temperature of about 5 hours or more, preferably about 5 to 24 hours. This heat treatment may be performed under standing conditions or under stirring conditions. The lubricating oil composition of the present invention may optionally contain other known additives as necessary. Other known additives include, for example, antioxidants such as phenol-based, amine-based and zinc dithiophosphate-based, cleaning / dispersing agents such as imide-based, ester-based, benzylamine-based, finate-based and salicylate-based, and amide-based additives. , Esters, fatty acids, etc. friction modifiers, metal sulfonates, succinates, sorbitan esters, etc., rust inhibitors, benzotriazoles, thiadiazoles, etc. metal deactivators, silicones, etc. Agents and the like.

[0025]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. The performance of the lubricating oil composition was evaluated according to the following procedure. <Filter paper weight loss> In a 100 ml wide-mouth bottle, 75 ml of sample oil was taken, and # 51 manufactured by ADVANTEC was used.
After immersing two sheets of B filter paper (20 × 80 mm, material: pure cellulose), cover with aluminum foil, and heat in a 175 ° C. constant temperature bath (air bath) for 40 hours. The weight of the filter paper before and after the test was weighed, and the weight loss was calculated by the following equation. The greater the weight loss, the greater the aggression on cellulose. Weight loss (% by weight) = [(weight before test−weight after test) / weight before test] × 100

The types of additives used are as follows. Additive 1: boronated polybutenyl succinimide (Lubrizol Corp. "L _z 935"), weight average molecular weight 95
0, B content 1.98% by weight, N content 2.05% by weight, total acid value 7.3mgKOH / g, base value 65.8mgKOH /
g, B / N weight ratio 0.97 Additive 2: Borated polybutenyl succinimide (“ECA5025” manufactured by Exxon Chemical Co., Ltd.), weight average molecular weight 9
50, B content 0.33% by weight, N content 1.35% by weight,
Total acid value 6.5 mg KOH / g, base value 32.5 mg KOH / g
g, B / N weight ratio 0.24 Additive 3: Borated polybutenyl succinimide (“EOA8015” manufactured by Ethyl Japan), weight average molecular weight 950, B content 1.15% by weight, N content 1 .46 wt%, total acid value 0.65 mgKOH / g, base value 45.2 mgK
OH / g, B / N weight ratio 0.79 Additive 4: Mono (2-ethylhexyl) hydrogen phosphate (manufactured by Sakai Chemical Co., Ltd.), P content 12% by weight, total acid value 320 mg KOH / g Additive 5: Phosphorus -Sulfuric terpene (Ethyl Japan Co., Ltd.), S content: 13% by weight, P content 4.8% by weight, total acid value 6.6mgKOH / g Additive 6: Polybutenyl succinimide (manufactured by Lubrizol Co., Ltd.) L _z 6406 "), N content 1.76 wt%, total acid number 1.5 mg KOH / g, a base number 46.8mgKOH / g additive 7: polybutenyl succinimide (Oro Knight Japan Ltd." OLOA373 " ), N content 1.05% by weight, total acid value 4.5 mg KOH / g, base value 20.1 mg KO
H / g

Examples 1 to 5 and Comparative 1 to 6 Paraffinic mineral oil 150 neutral oil [manufactured by Idemitsu Kosan Co., Ltd., kinematic viscosity: 30.7 mm ² / sec (40 ° C.), 5.28 m
m ² / sec (100 ° C.), viscosity index 104], and additives and additives shown in Table 1 based on the total amount of the composition, and 4,4′-methylenebis (2,4
6-di-tert-butylphenol) (manufactured by Ethyl Japan) 0.5% by weight, 4,4'-dioctyldiphenylamine (manufactured by Kawaguchi Chemical Industries) 0.5% by weight, oleic acid monoglyceride (manufactured by Kao Corporation) 0.5% by weight. 3% by weight, 1,2,3-benzotriazole (manufactured by Johoku Chemical Co., Ltd.) 0.02% by weight and polydimethylsiloxane (Shin-Etsu Chemical Co., Ltd.) 0.002% by weight
Was blended to produce a lubricating oil composition. Table 1 shows the performance evaluation results of each lubricating oil composition.

[0028]

[Table 1]

[0029]

[Table 2]

(Note) B content in oil: boron content derived from component (A) in lubricating oil composition N content in oil: nitrogen content derived from component (A) or other components in lubricating oil composition

[0031]

The lubricating oil composition of the present invention has improved peeling durability of a friction material, especially a cellose-based wet friction material, without impairing abrasion resistance and scoring resistance. It is suitable for a starting device made of cellulose and a friction material for a speed change clutch used in an automatic transmission.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) C10M 139/00 C10M 139/00 A // C10N 30:06 40:04 F term (reference) 4H104 BA02A BA07A BB33A BB34A BB47A BF03R BG02C BG04C BG10C BG12C BG13C BH02C BH03C BJ05C CB14A DA02A EA03C EA21C JA18 LA03 LA20 PA03

Claims (3)

[Claims] (1) The weight average molecular weight of (A) is 5 relative to the base oil.
00 to 3000, and the weight ratio of boron to nitrogen (B /
N) is a boron-containing imide-based dispersant having 0.1 to 1.5,
The boron content and the nitrogen content derived from the component (A) in the composition are 60 wt ppm or more and 100 wt pp, respectively.
m, a lubricating oil composition for a wet friction material for cellulose. 2. The lubricating oil composition for a cellulose-based wet friction material according to claim 1, wherein the boron-containing imide dispersant (A) is obtained by treating a polyalkenyl succinimide with a boron compound. 3. The lubricating oil composition for a cellulose-based wet friction material according to claim 1, further comprising (B) at least one selected from active phosphorus compounds and active sulfur compounds.