JPH0323593B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a grease composition, and more particularly to a grease composition comprising a thickener and a synthetic naphthenic hydrocarbon oil. Synthetic naphthenic hydrocarbons are used as base oils in grease compositions, but with the development of mechanical devices in which grease is used, it is necessary to select an appropriate grease to make these mechanisms function effectively. Not only that, but also high performance is required. The lubricant that serves as the base oil for ordinary grease compositions is
Lubricating oil produced from petroleum oil is used. However, it is well known that such mineral oil-based oils, even if refined, do not have the performance to function satisfactorily under severe conditions. Therefore, it is common practice to add various additives to such lubricating oils to improve their performance. However, even if adding additives improves some types of performance, other problems such as increased corrosion and increased sludge generation occur, making it difficult to achieve sufficient performance by adding additives alone. be. As the operating conditions of modern mechanical devices become more severe, longer lifespans are increasingly required. Since the deterioration phenomenon is largely due to the oxidation of the lubricating oil component of the base oil, the oxidation stability of the base oil has become a particularly important issue. Furthermore, as the uses of grease have expanded, the demand for a high traction coefficient has also increased. The present inventors have recognized that naphthenic hydrocarbon oil has excellent performance as a base oil for grease compositions, and have developed a grease composition that has excellent oxidation stability and excellent performance for use in rolling friction drive devices. As a result of various studies, it was recognized that a grease composition containing a specific naphthenic hydrocarbon oil having three hydrogenated six-membered carbon rings as a base oil has excellent performance and oxidation stability, and has developed the present invention. I was able to accomplish this. That is, the present invention provides a thickener and a general formula (However, in the formula, R ¹ is an alkylene group having 1 to 3 carbon atoms, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 3 carbon atoms, and l, m and n are 0 to 3 carbon atoms. (integer of 3, x is 0 or 1. Pour point of 70℃
This is a grease composition comprising a base oil having an aniline point of 0.08 or more and a traction coefficient of 0.08 or more. As the thickener used in the present invention, known thickeners can be used depending on the mode of use. Such thickeners include various metal bases such as lithium base, barium base, calcium base, aluminum base, soda base, and strontium base, as well as synthetic polymers, organosiloxanes, These include clay, bentonite, colloidal silica, and graphite. Compounds represented by the general formula include those represented by the following general formulas () and (). R ¹ is an alkyl-substituted alkyne group having 1 to 3 carbon atoms or a linear alkylene group, preferably a methylene group, an ethylene group, or a methyl-substituted methylene group. R ³ , R ⁴ and R ⁵ are alkyl groups having 1 to 3 carbon atoms which may be the same or different;
Preferably it is a methyl group or an ethyl group. l,
m and n are integers of 0 to 3, preferably 0
or 1. The total number of carbon atoms is 19 to 30, preferably 19 to 24, and more preferably 19 to 22. Among the compounds represented by the above general formula (), hydrogenated dibenzyltoluene, hydrogenated (benzylphenyl)phenylethane, or one to
Two methyl or ethyl substituents are preferred, and among the compounds of general formula () hydrogenated benzylbiphenyl or one or two methyl or ethyl substituents thereof are preferred for the purposes of the present invention. It is suitable for Examples of suitable compounds include hydrogenated dibenzyltoluene, hydrogenated 1,1-(benzylphenyl)
Phenylethane, hydrogenated 1,1-(benzyltolyl)phenylethane, hydrogenated benzylbiphenyl, hydrogenated 1,1-(biphenylyl)phenylethane, hydrogenated (ethylbiphenylyl)phenylmethane, hydrogenated 1,1-(ethylbiphenyl) (enylyl) phenylethane, hydrogenated methylbenzylbiphenyl, and the like. These compounds, for example, hydrogenated dibenzyltoluene can be obtained by hydrogenating dibenzyltoluene obtained by reacting benzyl halide and toluene in the presence of a Friedel-Crafts catalyst. Further, hydrogenated benzylbiphenyl can be obtained by hydrogenating benzylbiphenyl obtained by reacting benzyl halide and biphenyl in the presence of a Friedel-Crafts catalyst. The compounds obtained in this way are mixtures of isomers and, depending on the hydrogenation conditions, also mixtures with partially hydrogenated products. However, it is not only difficult to separate only specific compounds from these mixtures, but in many cases, the mixtures also exhibit good performance for the purpose of the present invention, so separation is not necessary. In this sense, the hydrogenation rate does not need to be completely 100%, but it is sufficient to make it 80% or more, preferably 90% or more. Furthermore, the compound used in the present invention has a pour point or crystal disappearance temperature (the temperature at which precipitated crystals completely dissolve by increasing the temperature) of 0°C.
It is necessary to have an aniline point of 70° C. or higher and a traction coefficient of 0.08 or higher.
Such a compound exhibits good performance when used as a base oil for a grease composition. Furthermore, the compound used in the present invention must have oxidation stability above a certain level, and in the test method of JIS K 2514-1980, the increase in viscosity ratio and total acid value is determined by an oxidation test under the following conditions. (mg KOH/g) and n
- The heptane insoluble content (wt%) is desirably 1.2 or less, 0.3 or less, and 0.3 or less, respectively.
Further, it is desirable that the oxidation life (RBOT) specified in ASTM D2272-67 is 250 minutes or more, preferably 300 minutes or more. The oxidation test was performed using 2,6-di-
The test was carried out on samples to which 0.5% by weight each of t-butyl para-cresol and zinc dialkyldithiophosphate were added. Oxidation test conditions

[Table] Oxidation catalyst Copper and iron Copper and iron
The traction coefficient referred to here is measured under the following conditions. The traction coefficient was measured using a Soda type cylindrical friction tester. Traction (rolling friction) occurs at three contact points between a central cylinder and three cylinders placed outside, and the same vertical load acts on the contact points. The surface pressure at this time is 0.575 to 1.157 GPa in terms of average Hertzian pressure. Other conditions are in Table 1
It is as follows.

[Table] The operating procedure for the experiment was to first keep the rotational speed of both the inner and outer cylinders constant, apply a weight, and then increase the slip rate by increasing only the rotational speed of the outer cylinder.
Changes in friction torque or traction coefficient with respect to slip rate were continuously determined. Friction torque is measured by directly measuring the torsional moment of the central free support shaft using a resistance wire strain gauge. The traction coefficient measured under these conditions shows a tendency to first rise linearly as the slip rate increases, and then to reach a maximum and then decline. In this case, the particularly important region from a practical standpoint is the initial linear region where the heat generated by the shear of the oil film is not large, and the traction coefficient in this region will be of particular interest below. As an example, the traction coefficients measured at an average Hertzian pressure of 1.157 GPa and a rotational speed of 4.19 m/s and a sliding speed of 0.022 m/s are as follows: Naphthenic mineral oil 0.05 Polyisobutylene hydride 0.06 Dicyclohexane 0.065 Dicyclohexylethane 0.075 α-methylstyrene linear The molecular hydride is 0.09, but the compounds represented by the general formula used in the present invention range from 0.08 to more than 0.095.
It is extremely superior to these hydrocarbons. A grease composition is prepared by mixing a thickener, a compound represented by the general formula, and additives added as necessary. Additives include antioxidants,
These include dispersants, viscosity index improvers, rust inhibitors, corrosion inhibitors, etc. The grease composition of the present invention can be suitably used for purposes other than grease for power transmission devices, that is, as a rolling bearing grease of ordinary grease. The grease composition of the present invention has the characteristics resulting from the fact that its base oil is a naphthenic hydrocarbon oil, and has the advantage that it has high oxidation stability and can be used for a long time under severe conditions. Next, the present invention will be explained in more detail by giving examples. In addition, "part" in the following examples,
Based on weight unless otherwise specified. Example 1 0.002 to 0.01 aluminum chloride in 3 parts of toluene
1 part of benzyl and warmed to 70℃, then 1 part of warmed benzyl
1 part was added and reacted for 2 hours. The reaction product was washed with water to remove the catalyst, and then distilled to separate unreacted substances. The obtained dibenzyltoluene (m->p
->0-isomer mixture) was fed into an autoclave, and an initial hydrogen pressure of 40 Kg/cm ² G was applied using a nickel catalyst.
A hydrogenation reaction was carried out at a temperature of 200° C. for 4 hours to obtain hydrogenated dibenzyltoluene (isomer mixture). To this hydrogenated naphthenic hydrocarbon oil, 0.5% by weight each of 2,6-di-tert-butyl para-cresol and zinc dialkyldithiophosphate were added as antioxidants, and an oxidation test was conducted under the conditions described above. Ta. Example 2 Similar tests were conducted on the following examples and on compositions similarly prepared from naphthenic hydrocarbon oils. The properties and test results of the hydrogenated naphthenic hydrocarbon oil are shown in Tables 2 and 3 together with other examples. Hydrogenated dibenzyltoluene as base oil (87%)
The properties of a grease composition thickened with lithium soap (13%) are shown in the table below (according to JIS K 2220-1980). The additives used at this time were 0.5% by weight of an antioxidant, 3% by weight of an extreme pressure additive, and 1.5% by weight of a rust inhibitor. Test item test results Mixing consistency (25℃) 280 Dropping point (℃) 185 Ash content (%) 0.9% Oxidation stability (Kg/cm ² ) (99℃×100hrs) 0.3 Oil separation degree (%) 4.7 Mixing stability 306 Chimken load capacity (lb) 2.5 Leakage (130°C x 6hrs) 3.2 Grease compositions were also prepared according to the performance of the base oil in the following examples. Example 2 0.001 to 0.005 mol of aluminum chloride was added to 4 mol of 1,1-diphenylethane, heated to 60°C, and then 1 mol of benzyl chloride was added and reacted for 20 minutes. Next, the reaction product was washed with water to remove the catalyst, and then distilled to separate unreacted substances. The obtained 1,1-(benzylphenyl)phenylethane (isomer mixture) was supplied to an autoclave, and the initial pressure of hydrogen was 100Kg and the temperature was 140-170K using a nickel catalyst.
Hydrogenation 1,1- was carried out at ℃ for 5 hours.
(Benzylphenyl)phenylethane (isomer mixture) was obtained. Example 3 Hydrogenated monoethyl-substituted 1,1-(benzylphenyl) was prepared in the same manner as in Example 2, except that 4 moles of monoethyl-substituted 1,1-diphenylethane was used instead of 1,1-diphenylethane. Phenylethane ( and A mixture of Example 4 One portion of methyldiphenylmethane and 200 ml of concentrated sulfuric acid were fed into a reactor and maintained at 15°C. Then, 800 ml of a 1:1 mixture of methyldiphenylmethane and styrene was added dropwise over a period of 2-3 hours, during which time the temperature of the reaction solution was maintained at 15-20°C. After the dropwise addition was completed, 200 ml of concentrated sulfuric acid was added and the reaction was maintained for 30 minutes. Next, the reaction product was washed repeatedly with water to remove sulfuric acid, and the monomethyl substitution 1,1 was carried out by distillation.
-(benzylphenyl)phenylethane was obtained.
Then, hydrogenation was performed in the same manner as in Example 2 to obtain hydrogenated monomethyl-substituted 1,1-(benzylphenyl)ethane ( and A mixture of Example 5 5 parts of biphenyl and 0.001~ of aluminum chloride
0.005 part was added and heated to 60°C, then 1 part of benzyl chloride was added and reacted for 20 minutes. The reaction product was washed with water to remove the catalyst, and then distilled to separate unreacted substances. The obtained benzyl biphenyl (isomer mixture) was supplied to autoclave No. 1, and an initial hydrogen pressure of 100 Kg/1 was added using a nickel catalyst.
cm ² G, hydrogenated benzylbiphenyl (isomer mixture) by hydrogenation reaction for 2 hours at a temperature of 140-170°C.
I got it. Example 6 In Example 5, 5 parts of monoethylbiphenyl and 0.03 parts of aluminum chloride were used instead of biphenyl.
Hydrogenated benzylmonoethylbiphenyl ( and A mixture of Example 7 A reactor was charged with 1 cyclohexylbenzene and 200 ml of concentrated sulfuric acid and kept at 15°C. Then, 800 ml of a 1:1 mixture of cyclohexylbenzene and styrene was added dropwise over a period of 2-3 hours, during which time the temperature of the reaction solution was maintained at 15-20°C. After the dropwise addition was completed, 200 ml of concentrated sulfuric acid was added and the reaction was continued for 30 minutes. The reaction product was then repeatedly washed with water to remove sulfuric acid, and 1,1-(cyclohexyl phenyl) phenylethane (isomer mixture) was obtained by distillation. Next, 1,1-(cyclohexylphenyl)phenylethane 1 was supplied to the autoclave, and the initial pressure of hydrogen was increased to 100 using a nickel catalyst.
A hydrogenation reaction was carried out at Kg/cm ² G and a temperature of 140 to 170° C. for 2 hours to obtain hydrogenated 1,1-biphenylyl)phenylethane (isomer mixture). Example 8 Same procedure as in Example 7 except that cyclohexylbenzene was replaced by monoethylbiphenyl 1 and 800 ml of a 1:1 mixture of monoethylbiphenyl and styrene was used instead of the mixture of cyclohexylbenzene and styrene. Hydrogenated 1,1-(ethylbiphenylyl)phenylethane ( and A mixture of Example 9 In Example 4, monomethylbenzyl chloride was used instead of biphenyl, and the reaction temperature was changed to 80°C.
Hydrogenated methylbenzylphenyl was produced in the same manner as in Example 4 except that the temperature and reaction time were 1 hour.

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Claims (1)

[Claims] 1. Grease compositions (excluding grease compositions for power transmission devices) containing a thickener and a general formula (However, in the formula, R ¹ is an alkylene group having 1 to 3 carbon atoms, R ³ , R ⁴ and R ⁵ are each independently an alkyl group having 1 to 3 carbon atoms, and l, m and n are 0 to 3 carbon atoms. (integer of 3, X is 0 or 1. Pour point of 70℃
A grease composition comprising a base oil having an aniline point of 0.08 or more and a traction coefficient of 0.08 or more.