JPH09188887A - Heat-resistant lubricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricating oil compsn. improved in utility value and heat, oxidation and abrasion resistances under severe conditions such as high- temp. conditions in particular by blending a specific base oil with a sulfur-contg. abrasion resistance improver. SOLUTION: 10-90wt.% organopolysiloxane of 2 to 25cSt in dynamic viscosity at 100 deg.C and of the general formula I (wherein R<1> to R<8> are each 1-8C alkyl, 6-18C aryl which may be substd. by 1-12C alkyl and is pref. phenyl; and x is 1 to 5), which is an organosilicon compd. polymer having a skeleton of siloxane bonds and having hydrocarbon groups each bonded directly to a silicon atom, is mixed with 90-10wt.% polyphenylthioether of the general formula II (wherein R<9> to R<11> are each H or a 1-24C hydrocarbon group; x, y and z are each 1 to 4; and m is 1 to 3) having aromatic rings each bonded to a sulfur atom at the m-position, and 0.1 to 7wt.% (based on the whole compsn.) dibenzyl sulfide compd. of the general formula III (wherein R<12> and R<13> are each a 1-10C hydrocarbon group; and n is 1 to 5) as a sulfur-contg. abrasion resistance improver to obtain a lubricating oil compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant lubricating oil composition, and more specifically, it is composed of a mixture of organopolysiloxane and polyphenylthioether and is used in a high temperature region such as a jet engine and a compressor. The present invention relates to a lubricating oil composition having excellent heat resistance, oxidation resistance and wear resistance.

[0002]

2. Description of the Related Art In recent years, with the advancement of performance and efficiency due to technological advances in mechanical devices and power devices, there has been a demand for lubricating oils having a high quality capable of withstanding severe usage conditions. For example, lubricating oils used under high temperature conditions such as jet engine oil, gas turbine oil, hydraulic oil, compressor oil, vacuum pump oil, bearing oil, etc., are particularly excellent in heat resistance and oxidation resistance. It has become indispensable.

Therefore, although organopolysiloxanes have been proposed as lubricating oils that can withstand use under high temperature conditions, which are becoming increasingly severe, for example, organopolysiloxanes such as alkylmethylpolysiloxane have excellent oxidation resistance. However, there is a problem in wear resistance particularly on the sliding surface between steel and steel, and its solution has been earnestly desired.

[0004]

SUMMARY OF THE INVENTION In view of the above demands for heat-resistant lubricating oils, the present invention is heat-resistant and durable enough to be used under severe operating conditions, especially high-temperature conditions, which cannot be achieved by conventional lubricating oils. An object of the present invention is to provide a heat resistant lubricating oil composition having excellent oxidation resistance and abrasion resistance and high practical value.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
In order to solve the above-mentioned problems, as a result of extensive studies, a mixture of organopolysiloxane and polyphenylthioether having 3 to 5 aromatic rings has excellent heat resistance and oxidation resistance which cannot be achieved alone. Focusing on a novel heat-resistant lubricating oil composition having wear resistance, the inventors have found that this can solve the above-mentioned problems, and have reached the present invention.

Thus, according to the present invention, (a) the general formula [I]:

[0007]

Embedded image (In the above general formula [I], R ^{1 to} R ⁸ may be the same or different from each other, each is an alkyl group or an aryl group, and x is 1 to 10
Is an integer. ), And (b) the following general formula [II]:

[0008]

Embedded image (In the above general formula [II], R ⁹ , R ¹⁰ and R ¹¹
May be the same or different from each other, each is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, and x, y and z may be the same or different from each other. They may be different, are integers of 1 to 4, and m is an integer of 1 to 3. The present invention provides a heat resistant lubricating oil composition comprising a base oil comprising a mixture containing a polyphenyl thioether represented by the formula (1) and a sulfur-based antiwear agent.

According to the present invention, as a preferred embodiment, the organopolysiloxane represented by the general formula [I] is represented by the following general formula [III]:

[0010]

Embedded image (In the above general formula [III], R ¹ , R ² , R ^{4 to} R ^4
6 is a methyl group or a phenyl group, x is 1 to 10
Is an integer. The heat-resistant lubricating oil composition is phenylmethylpolysiloxane represented by the formula (1), and the polyphenylthioether represented by the general formula [II] is m-bis (phenylmercapto) benzene (m).
-3P2T), bis (m-phenylmercaptophenyl) sulfide (m, m-4P3T) and m-bis (m-phenylmercaptophenylmercapto) benzene (m, m, m-5P4T) And a heat-resistant lubricating oil composition comprising a mixture of 10% by weight to 90% by weight of the organopolysiloxane and 10% by weight to 90% by weight of the polyphenylthioether. To be done.

A feature of the present invention is that organopolysiloxane and polyphenylthioether having 3 to 5 aromatic rings are mixed alone, even though they are inferior in lubricity and abrasion resistance, respectively. Furthermore, by adding a sulfur-based antiwear agent, it is possible to provide a lubricating oil composition in which both heat resistance and oxidation resistance and antiwear properties are improved, and at the same time physical properties such as pour point and viscosity index are also improved. .

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Organopolysiloxane Polyorganopolysiloxane used as a component of the heat resistant lubricating oil composition of the present invention is a polymer of an organosilicon compound having a siloxane bond as a skeleton and a hydrocarbon group directly bonded to a silicon atom. General formula [I]:

[0013]

Embedded image It is represented by In the general formula [I], R ^{1 to} R ⁸ are the same or different alkyl groups or phenyl groups, and examples of the alkyl group include a linear or branched alkyl group having 1 to 18 carbon atoms; The aryl group may be an aryl group having 6 to 18 atoms, and the aryl group may be substituted with an alkyl group having 1 to 12 carbon atoms. The alkyl group preferably has 1 to 8 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group,
Examples thereof include a heptyl group and an octyl group, and a short-chain group is particularly preferable. Examples of the aryl group include a phenyl group, a tolyl group, a xynyl group and the like, and a phenyl group is particularly preferable. Further, x can be arbitrarily selected depending on the desired viscosity, but it is an integer of 1 to 10, particularly preferably an integer of 1 to 5.

According to the invention, the preferred organopolysiloxanes have the general formula [III]:

[0015]

Embedded image It is represented by In the general formula [III], R ¹ , R
² , R ⁴ and R ⁵ R ⁶ may be the same or different from each other and are each an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 12 carbon atoms. Most commonly, a methyl group is used as the alkyl group, but other higher alkyl groups and phenyl groups are used together to improve the lubricity between dimethyl silicone steel and steel and heat resistance. . Specific examples include alkylmethylpolysiloxane and phenylmethylpolysiloxane. For example, as the alkylmethylpolysiloxane, ethylmethylpolysiloxane, octylmethylpolysiloxane, or the like is used.

In the above general formula [III], x is 1 to
It is an integer of 10, and in particular, an integer of 2 to 5 is preferable from the viewpoint of improving viscosity and abrasion resistance.

Therefore, according to the present invention, the above general formula [I
II] is most preferable, but more specifically, the following structural formula (a):

[0018]

Embedded image (In the structural formula (a), x is an integer of 1 to 10, preferably an integer of 1 to 5.) Phenylmethylpolysiloxane represented by the following structural formula (b):

[0019]

Embedded image Pentaphenyltrimethyltrisiloxane represented by
The following structural formula (c):

[0020]

[Chemical 6] And tetraphenyltetramethyltrisiloxane represented by

The organopolysiloxane of the present invention has a kinematic viscosity at 100 ° C. of 2 cSt to 25 cS.
t, preferably 4 cSt to 10 cSt is used. Polyphenyl thioether The polyphenyl thioether used as a component of the heat resistant lubricating oil composition of the present invention has a structure in which an aromatic ring is bound by a sulfur atom, and has the following general formula [II]:

[0022]

Embedded image It is represented by

In the above general formula [II], R ⁹ , R ¹⁰
And R ¹¹ may be the same as or different from each other, and each is a hydrogen atom or a carbon number of 1 to 2.
4 hydrocarbon groups. A compound in which all of R ⁹ , R ¹⁰ and R ¹¹ are hydrogen atoms represents a hydrocarbon-unsubstituted polyphenyl thioether. As the hydrocarbon group, for example, a linear or branched alkyl group having 1 to 24 carbon atoms; 2 to 2 carbon atoms
24 straight or branched alkenyl groups; 6 to 2 carbon atoms
4 cycloalkyl group; an aryl group having 6 to 24 carbon atoms, and the like. The aryl group has 1 to 1 carbon atoms as a substituent.
It may have 12 alkyl groups or 2 to 12 alkenyl groups. A preferred hydrocarbon group has 6 to 20 carbon atoms.
Is an alkyl group, specifically, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, A nonadecyl group, an eicosyl group and the like and those having these branches are used. Especially carbon number 8-18
Are preferred. The hydrocarbon group may be bonded to any position of the aromatic ring.

In the above general formula [II], x, y and z are the same or different from each other.
It is an integer of 1 to 4.

In the above general formula [II], m is 1 to 3
And the polyphenylthioether of the present invention includes compounds containing 3 to 5 aromatic rings.

The thioether bond of the polyphenyl thioether may be bonded at any position of the aromatic ring, but from the viewpoint of maintaining fluidity, the bond at the meta position is preferable.

Therefore, as the polyphenyl thioether represented by the general formula [II], both hydrocarbon-unsubstituted polyphenyl thioether and hydrocarbon-substituted polyphenyl thioether are used.

Hydrocarbon-unsubstituted polyphenyl thioethers have the general formula [IV]:

[0029]

Embedded image (In the above general formula [IV], m is an integer of 1 to 3.) In the present invention, in addition to improving heat resistance, oxidation resistance and wear resistance, the viscosity of the lubricating oil composition and other From the viewpoint of adjusting physical properties, it is a particularly preferable compound.

Specific examples of the hydrocarbon-unsubstituted polyphenyl thioether are as follows. That is, m-bis (phenylmercapto) benzene (m-3
P2T), o-bis (phenylmercapto) benzene (o-3P2T), p-bis (phenylmercapto) benzene (p-3P2T), bis (phenylmercapto)
Benzene isomer mixture (mix-3P2T), bis (m
-Phenylmercaptophenyl) sulfide (m, m
-4P3T), bis (o-phenylmercaptophenyl) sulfide (o, o-4P3T), bis (p-phenylmercaptophenyl) sulfide (p, p-4)
P3T), m-phenylmercaptophenyl p-phenylmercaptophenyl sulfide (m, p-4P3
T), m-phenylmercaptophenyl o-phenylmercaptophenyl sulfide (m, o-4P3T),
p-phenylmercaptophenyl o-phenylmercaptophenyl sulfide (p, o-4P3T), bis (phenylmercaptophenyl) sulfide isomer mixture (mix-4P3T), m-bis (m-phenylmercaptophenylmercapto) benzene (m, m, m-
5P4T), 1- (m-phenylmercaptophenylmercapto) -3- (p-phenylmercaptophenylmercapto) benzene (m, m, p-5P4T), p-bis (m-phenylmercaptophenylmercapto) benzene (m, m). In addition to p, m-5P4T), a bis (phenylmercaptophenylmercapto) benzene isomer mixture (mix-5P4T) and the like can be mentioned.

Further, as a specific example of the hydrocarbon-substituted polyphenyl thioether, a mono-obtained product obtained by bonding 1 to 3 alkyl groups having 6 to 20 carbon atoms as described above in the molecule,
Included are di- or tri-alkylated polyphenyl thioethers. For example, mono-alkylated m- bis (phenylmercapto) benzene (R-m-3P2T), dialkylated m- bis (phenylmercapto) benzene (R ₂ -
m-3P2T), addition of tri-alkylated m- bis (phenylmercapto) benzene (R ₃ -m-3P2T), bis (m- phenylmercapto phenyl) sulfide (m, m-4P3T), m- bis (m- Phenylmercaptophenylmercapto) benzene (m, m, m-5P
An example is an alkylated product of 4T).

The above-mentioned hydrocarbon-unsubstituted polyphenyl thioether and hydrocarbon-substituted polyphenyl thioether are
One type or two or more types that are normally liquid are used. Among the compounds exemplified above, m-bis (phenylmercapto) benzene (m-3P, which is a hydrocarbon-unsubstituted polyphenylthioether for the lubricating oil composition of the present invention.
2T), o-bis (phenylmercapto) benzene (o
-3P2T), p-bis (phenylmercapto) benzene (p-3P2T), bis (m-phenylmercaptophenyl) sulfide (m, m-4P3T) and m-.
As described above, bis (m-phenylmercaptophenylmercapto) benzene (m, m, m-5P4T) and the like are particularly useful from the viewpoint of improving heat resistance / oxidation resistance, wear resistance and physical properties of the lubricating oil composition. .

The method for producing the above polyphenyl thioether will be described by taking m-bis (phenylmercapto) benzene as an example. First, thiophenol metal salt and m
-Reacting dihalogenobenzene in the presence of a copper catalyst to produce m-bis (phenylmercapto) benzene (pre-reaction). m-Bis (phenylmercapto) benzene (m-3P2T) can be obtained by collecting a desired fraction from the product of this first-stage reaction.

Next, to prepare hydrocarbon-substituted m-bis (phenylmercapto) benzene, m-bis (phenylmercapto) benzene is reacted with α-olefin in the presence of a Lewis acid catalyst to alkylate m-bis. It is possible to produce (phenylmercapto) benzene (second-stage reaction).

In the first-step reaction, N is used as the polar solvent.
-Methyl-2-pyrrolidone, N-propyl-2-pyrrolidone, dimethylacetamide, dimethylformamide and the like are used, and as the thiophenol metal salt, thiophenol sodium salt, thiophenol potassium salt and the like are used. Further, as the copper catalyst, copper chlorides such as cuprous chloride and cupric chloride, copper oxides such as cuprous oxide and cupric oxide, and the like are used. As m-dihalogenobenzene,
Examples thereof include m-dibromobenzene and m-dichlorobenzene. The thiophenol metal salt and m-dihalogenobenzene are mixed at a ratio of 3: 1 to 2: 1 and a temperature of 160 ° C to 21 ° C.
The reaction is carried out at a temperature of 0 ° C. In the second reaction, 0.3 mol to 3 mol of α-olefin is mixed with 1 mol of m-bis (phenylmercapto) benzene obtained in the first reaction, and the mixture is subjected to the reaction at a temperature of 80 ° C to 100 ° C. As the Lewis acid catalyst used in the second-stage reaction, boron fluoride, aluminum chloride or the like is used.

From the reaction product obtained as described above,
A predetermined fraction was collected by a method such as vacuum distillation, and alkylated m-bis (phenylmercapto) benzene (R-m
-3P2T) can be isolated. Sulfur-Based Antiwear Agent A sulfur-based antiwear agent is incorporated as an essential component of the heat-resistant lubricating oil composition of the present invention. As a sulfur-based antiwear agent,
General formula [V]:

[0037]

Embedded image Sulfur compounds represented by are preferred. In the general formula [V], R ¹² and R ¹³ are hydrocarbon groups having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms, and particularly preferable hydrocarbon groups are alkylene groups having 1 to 2 carbon atoms. To be n is an integer of 1 to 5, preferably 1 to 3.

As the sulfur compound of the above-mentioned general formula [V], specifically, a dibenzyl sulfide compound can be used.

As the sulfur antiwear agent, sulfurized fats and oils and other paraffinic sulfides can be used together with or independently of the sulfur compound of the general formula [V].
The content of these sulfur compounds is 0.1% to 7% by weight, preferably 1% to 5% by weight based on the total weight of the composition.
% By weight. Lubricating Oil Composition The heat-resistant lubricating oil composition of the present invention contains (a) an organopolysiloxane, (b) a polyphenylthioether having 3 to 5 aromatic rings, and (c) a sulfur-based antiwear agent. Is. The mixing ratio thereof is, based on the total weight of the lubricating oil composition, (a) 10% by weight to 90% by weight of organopolysiloxane and (b) 90% by weight to 1% by weight of polyphenylthioether.
0% by weight, and a preferable ratio is (a) 20% by weight to
70% by weight (b) 80% by weight to 30% by weight. A particularly preferable ratio is (a) 40% by weight to 60% by weight (b)
It is 60% to 40% by weight. By mixing the organopolysiloxane and the polyphenyl thioether in the above ratio, each alone improves poor wear resistance,
Heat resistance and oxidation resistance can be further improved. If the mixing ratio of the organopolysiloxane is less than 10% by weight, the abrasion resistance is inferior, while if it exceeds 90% by weight, the abrasion resistance is similarly deteriorated.

As the heat-resistant lubricating oil composition of the present invention, by mixing the two, a kinematic viscosity at 100 ° C. of 2 cSt to 30 cSt, particularly 3 cSt to 10 cSt is usually obtained. A lubricating oil composition having controlled physical properties such as viscosity can be obtained by mixing with a substituted polyphenyl thioether, for example, m-triphenyl thioether.

Commercially available products of the above organopolysiloxanes include, for example, Silicone F5 manufactured by Shin-Etsu Chemical Co., Ltd.
Etc. can be used. Also, as a sulfur antiwear agent, Dai Nippon Ink Chemical Co., Ltd. Dailoop S
-700 and DILOVE S-320 can be used.

As an additive to the heat-resistant lubricating oil composition of the present invention, if necessary, for example, an antiwear agent other than a sulfur antiwear agent, an antioxidant, a viscosity index improver, a pour point depressant,
Corrosion inhibitors, metal deactivators and the like can be added as appropriate. Generally, as an antiwear agent, a general formula (RO ₃ ) P =
Examples thereof include compounds represented by O (in the formula, R is an alkyl group or an aryl group, which may be the same or different). For example, trialkyl phosphate, tricresyl phosphate, triphenyl phosphate, benzyl diphenyl phosphate, phosphoric acid ester such as ethyl diphenyl phosphate, zinc dialkyldithiophosphate and the like can also be used. These are usually 0.01% by weight to
It is used in a proportion of 7% by weight, preferably 1% to 5% by weight. In comparison with adding the antiwear agent to each of the organopolysiloxane and the polyphenyl thioether, the antiwear property can be further improved by adding it to the mixed oil of these.

Examples of the antioxidant include alkylated diphenylamine (alkyl group having 4 to 20 carbon atoms), triphenyldiamine, phenyl-α-naphthylamine, alkylated phenyl-α-naphthylamine, phenothiazine, alkylated phenothiazine. Amine-based antioxidants such as 2,6-di-t-butylphenol, 4,
Phenolic antioxidants such as 4'-methyl-bis- (2,6-di-t-butylphenol), dilauryl thiodipropionate, distearyl thiodipropionate,
Sulfur-based antioxidants such as dimyristylthiodipropionate, and sulfur such as zinc dialkyldithiophosphate.
Phosphorus antioxidants and the like can be mentioned, and these are usually used in a proportion of 0.05% by weight to 5% by weight, preferably 0.1% by weight to 3% by weight.

Examples of the viscosity index improver include polymethacrylate type, polyisobutylene type, ethylene-propylene copolymer type, styrene-butadiene hydrogenated copolymer type, and the like. It is used in a proportion of 35% by weight to 35% by weight.

Examples of the corrosion inhibitor include isostearate, n-octadecyl ammonium stearate,
Duomin T.diolate, lead naphthenate, sorbitan oleate, pentaerythritol oleate, oleyl sarcosine, alkenyl succinic acid or a partial ester thereof and the like can be mentioned, and 1% by weight or less, preferably 0.01% by weight to 0.5%. Used by weight percent.

Examples of the metal deactivator include benzotriazole, thiadiazole and the like, and these are usually used in a proportion of 0.01% by weight to 3% by weight.

The heat-resistant lubricating oil composition obtained as described above is a jet engine oil, a turbocharger engine oil, a super heat-resistant adiabatic engine oil, a gas turbine oil, a diffusion pump oil, a rotary pump oil used at high temperature. Etc. can be used.

[0048]

The present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

The corrosion oxidation stability test method and the four-ball test method used for evaluating the performance of the lubricating oil composition of the present invention will be described. Corrosion and Oxidation Stability Test (COS Test) This test method is Federal Test Method.
Determined in accordance with STD 791-5308, 100 ml of sample oil is taken, and Ag, Al, F are used as oxidation catalysts.
Using e and Ti, air was blown at a rate of 5 liters per hour for 72 hours at a temperature of 230 ° C. to perform oxidation treatment, and then weight change of metal piece before and after oxidation treatment, viscosity change, total acid value change and oxidation treatment. Measure the amount of sludge produced afterwards.

In the test items, the change in weight of the metal piece is determined to be ± 0.2 mg / cm ² or less in terms of change in weight of metal piece / surface area. The change in viscosity is the rate of change in kinematic viscosity (%) at 40 ° C, and the change in total acid value is the difference in total acid value (mgKOH
The amount of sludge produced is the weight of the residue (mg / 100 ml) after filtering the sample oil after oxidation with a 10 μm pore size filter manufactured by Millipore. Four-ball test shell In a wear test using a four-ball tester, ASTM
According to 4172, the following test conditions are adopted, and test balls made of the following three materials are used as a rotating ball and a fixed ball as shown in each example. The average value of the average wear scar diameter (mm) of the three fixed balls after 30 minutes of operation is determined.

Test conditions: Temperature (° C.): 80 Load (kg): 30 Rotational speed (rpm): 1,200 Test ball: SUJ-2 (high carbon chromium steel) M-50 (heat resistant steel) Si ₃ N ₄ (Silicon Nitride Ceramics) Example 1 Pentaphenyltrimethyltrisiloxane and m-bis (phenylmercapto) benzene (m
-3P2T) and 5% by weight of dibenzyl disulfide in the mixture obtained based on the total weight of the composition.
A lubricating oil composition was prepared by adding. Table 1 shows the results of performance evaluation by the above-mentioned corrosion oxidation stability test and four-ball test.

Example 2 A lubricating oil composition was prepared in the same manner as in Example 1, except that sulfurized fats and oils were added in place of dibenzyl disulfide in an amount of 5% by weight based on the total weight of the composition. The results of the performance evaluation are shown in Table 1.

Comparative Example 1 Using only pentaphenyltrimethyltrisiloxane,
The performance was evaluated by the above corrosion oxidation stability test and four-ball test, and the test results are shown in Table 1 together with general properties such as viscosity and viscosity index.

Comparative Example 2 m-bis (phenylmercapto) benzene (m-3P
A tricresyl phosphate was added to T) in an amount of 4% by weight based on the total weight of the composition to prepare a lubricating oil composition, which was subjected to the performance evaluation by the above corrosion oxidation stability test and four-ball test. Table 1 shows the test results.

Comparative Example 3 60% by weight of pentaphenyltrimethyltrisiloxane and m-bis (phenylmercapto) benzene (m-3P2
T) 40% by weight was mixed to prepare a lubricating oil composition, which was subjected to performance evaluation by the above-mentioned corrosion oxidation stability test and four-ball test. The test results are shown in Table 1 together with general properties such as viscosity and viscosity index of the lubricating oil composition.

Comparative Example 4 60% by weight of pentaphenyltrimethyltrisiloxane and m-bis (phenylmercapto) benzene (m-3P2
T) 40% by weight of tricresyl phosphate was added to the mixed oil in an amount of 4% by weight based on the total weight of the composition to prepare a lubricating oil composition, which was subjected to the above performance evaluation. Table 1 shows the test results.

[0057]

[Table 1] Note 1) Pentaphenyltrimethyltrisiloxane: Shin-Etsu Chemical Co., Ltd. Silicone F5 Note 2) Dibenzyl disulfide: Dainippon Ink and Chemicals Co., Ltd. DILOVE S-700 Note 3) Sulfurized fats and oils: Dainippon Ink and Chemicals Co., Ltd. DAILUBE S-320 From the above-described examples and comparative examples, a sulfur-based antiwear agent is added to a base oil obtained by mixing the organopolysiloxane according to the present invention and m-bis (phenylmercapto) benzene. In the lubricating oil composition, organopolysiloxane or m-bis (phenylmercapto) benzene alone had poor wear resistance even if a phosphorus-based antiwear agent was added, whereas the mixture had a sulfur-based antiwear property. Shows extremely excellent wear resistance by incorporating an abrasive, and has high heat resistance, oxidation resistance and wear resistance. It is clear that. In particular, from the comparison between Examples 1 and 2 and Comparative Example 1,
It has been shown that an excellent heat resistant lubricating oil can be obtained by mixing pentaphenyltrimethyltrisiloxane, which is difficult to use alone as a lubricating oil, with m-bis (phenylmercapto) benzene.

[0058]

INDUSTRIAL APPLICABILITY Generally, organopolysiloxanes are excellent in heat resistance and oxidation resistance, but have poor lubricity between steels.
By mixing the organopolysiloxane according to the present invention with polyphenyl thioether, and by further incorporating a sulfur-based antiwear agent, the lubricity is improved and excellent heat resistance and acid resistance capable of withstanding even under severe high temperature conditions. It is possible to obtain a lubricating oil composition having chemical resistance and wear resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C10N 30:08 30:10

Claims (1)

[Claims] 1. The following general formula [I]: (In the above general formula [I], R ^{1 to} R ⁸ may be the same or different from each other, each is an alkyl group or an aryl group, and x is 1 to 10
Is an integer. ) And the following general formula [II]: (In the above general formula [II], R ⁹ , R ¹⁰ and R ¹¹
May be the same or different from each other, each is a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, and x, y and z may be the same or different from each other. They may be different, each is an integer of 1 to 4, and m is an integer of 1 to 3. The heat resistant lubricating oil composition which mix | blends the sulfur type antiwear agent with the base oil which consists of the mixture containing the polyphenyl thioether represented by these.