JPH0369960B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing diurea-based grease, and more particularly to a method for producing diurea-based grease with excellent low noise properties. For example, some greases, such as grease for sealed ball bearings, are strongly required to have low noise properties. Lithium-based grease is most widely used as such low-noise grease, but this tends to generate noise when used at high temperatures for long periods of time. On the other hand, high-temperature greases have also been developed, and various thickeners for high-temperature greases are known, one of which is diurea compounds. This high-temperature grease can be used for a long period of time at high temperatures, for example, 120° C. or higher, but it has poor acoustic properties and can hardly be used in places where low noise is required. SUMMARY OF THE INVENTION An object of the present invention is to provide a grease that can be used for a long period of time at high temperatures, particularly at temperatures above 120°C, and has excellent low noise properties. That is, in the present invention, an amine compound is dissolved in a lubricating oil, an isocyanate compound is further added thereto together with the lubricating oil as necessary to cause the amine compound and the isocyanate compound to react, and then the reaction product is heated. When producing diurea-based grease, one or more of alkenylsuccinimide, metal alkylbenzene sulfonate, and metal petroleum sulfonate are present during the reaction between the amine compound and the isocyanate compound. The present invention relates to a method for producing low-noise diurea-based grease. According to the research conducted by the present inventors, diurea-based grease can be improved by allowing at least one of alkenylsuccinimide, alkylbenzene sulfonic acid metal salt, and petroleum sulfonic acid metal salt to be present in the reaction system during the production of diurea-based grease. It has been found that it exhibits excellent low-noise properties and that its low-temperature properties hardly deteriorate even when used for a long time at high temperatures of 120°C or higher. The above-mentioned remarkable effects can only be obtained by adding these compounds during the production of diurea grease, and cannot be obtained by simply adding them to the grease after production. The alkenyl succinimide used by the present inventor has a molecular weight of 1000 to 2000, preferably 1200.
It is about ~1500. The alkylbenzenesulfonic acid of the alkylbenzenesulfonic acid metal salt has a molecular weight of 250 to 550, preferably 350 to 450, and the metal salt includes alkali metals such as sodium and potassium, alkaline earth metals such as barium, calcium, and magnesium. Examples include petroleum sulfonic acid metal salts such as alkali metal or alkaline earth metal petroleum sulfonic acids having a molecular weight of 250 to 550, preferably 350 to 450.
These compounds can be used alone or in a mixture of two or more, and are usually blended in an amount of about 0.5 to 30 parts by weight, preferably about 5 to 15 parts by weight, based on 100 parts by weight of the base thickener. In the present invention, any of the conventionally known diurea greases to be blended with these compounds can be used in a wide range. More specifically, diisocyanates that are to be used to produce diurea compounds and monoamines that have been conventionally used can be used effectively as they are; examples of diisocyanates include 4,4'-diphenylmethane diisocyanate and 2,4'-toluylene diisocyanate. Isocyanates, phenylene diisocyanates, etc., and monoamines include aliphatic amines such as stearylamine, oleylamine, etc., and aliphatic amines such as cyclohexylamine. As the base lubricant, conventionally used lubricants can be used, such as mineral oils as well as synthetic oils, and preferably have a viscosity of about 2 to 20 cst at 100°C. The proportion of these diurea compounds in the lubricating oil may be the same as conventional ones, usually 0.5 to 30 parts by weight per 100 parts by weight of the lubricating oil, preferably 10 to 30 parts by weight.
It is about 15 parts by weight. The diurea-based grease used as the base grease in the present invention is prepared by first dissolving an amine-based compound in a lubricating oil, and then adding an isocyanate-based compound, preferably mixed with the lubricating oil in advance, under stirring, so that the two react. It is obtained by heating, usually at around 150°C. In the production method of the present invention, it is an essential condition that the various compounds mentioned above, such as petroleum sulfonates, are added so that they coexist during the reaction. Therefore, it may be added in advance before the reaction, and it is particularly preferable to mix it into the lubricating oil at the same time as the amine compound. The present invention will be explained below with reference to Examples. Example 1 Lubricating oil (100°C viscosity 12.9cst) 82.3g Stearylamine 9.1g Oleylamine 3.0g 4,4'-diphenylmethane diisocyanate
5.6g Calcium sulfonate (metallic petroleum sulfonate, average molecular weight approximately 550 as an acid) 1.9g Antioxidant 1.0g 9.1g stearylamine, 3.0g oleylamine, calcium sulfonate in 41.4g lubricating oil
Mix 1.9g and heat to 100°C with stirring to dissolve. Separately, 5.6 g of 4,4'-diphenylmethane diisocyanate was mixed in 41.2 g of lubricating oil, heated to 100°C, and dissolved with stirring. This is gradually added to the amine solution to uniformly disperse the diurea compound into the lubricating oil. After that, heat to 150℃ while stirring and hold for 15-40 minutes.
The desired grease is obtained by cooling and stirring to room temperature, adding 1.0 g of antioxidant, and processing using a three-stage roll. Example 2 Lubricating oil (100°C viscosity 12.9cst) 82.3g Stearylamine 9.1g Oleylamine 3.0g 4,4'-diphenylmethane diisocyanate
5.6g Barium sulfonate (petroleum sulfonate metal salt, average molecular weight: approx. 550 as an acid) 1.9g Antioxidant 1.0g The manufacturing method is the same as in Example 1 except that calcium sulfonate was replaced with barium sulfonate. Same as 1. Example 3 Lubricating oil 82.3g Stearylamine 9.1g Oleylamine 3.0g 4,4'-diphenylmethane diisocyanate
5.6g Oroa 1200 (trademark, alkenyl succinimide)
2.5g Antioxidant 1.0g The manufacturing method is the same as in Example 1 except that the calcium sulfonate in Example 1 was replaced with Oroa 1200. Example 4 Lubricating oil 90.0g Cyclohexylamine 4.4g 4,4'-diphenylmethane diisocyanate
5.6g Calcium sulfonate (petroleum sulfonic acid metal salt, average molecular weight approximately 550 as an acid) 1.9g Antioxidant 1.0g Cyclohexylamine 5.6g in 45.0g lubricating oil,
Mix 1.9g of calcium sulfonate and heat to 100℃
Heat and stir to dissolve. Separately, add 5.6 g of 4,4'-diphenylmethane diisocyanate to the lubricating oil.
Mix 45.0g and dissolve at 100℃. This is gradually added to the amine solution to uniformly disperse the diurea compound in the lubricating oil. The subsequent manufacturing method is the same as in Example 1. Comparative example 1 Lubricating oil (100°C viscosity 12.9cst) 82.3g Stearylamine 9.1g Oleylamine 3.0g 4,4'-diphenylmethane diisocyanate
5.6g Antioxidant 1.0g The manufacturing method was the same as in Example 1 except that calcium sulfonate was removed. Comparative example 2 Lubricating oil (100°C viscosity 8.0cst) 90.0g cyclohexylamine 4.4g oleylamine 3.0g 4,4'-diphenylmethane diisocyanate
5.6g Antioxidant 1.0g The manufacturing method was the same as in Example 4 except that calcium sulfonate was removed. Comparative Example 3 Grease of Comparative Example 1 100g Calcium Sulfonate 1.9g The manufacturing method was to mix 100g of the grease obtained in Comparative Example 1 with 1.9g of calcium sulfonate. Comparative Example 4 Grease of Comparative Example 1 100g Barium Sulfonate 1.9g The manufacturing method was to mix 100g of the grease obtained in Example 1 with 1.9g of Barium Sulfonate. Comparative Example 5 Grease of Comparative Example 1 100g Oroa 1200 2.5g The manufacturing method was to mix 100g of the grease obtained in Example 1 with 2.5g of Oroa 1200. Each of the greases obtained by the above manufacturing method was sealed in a sealed ball bearing, and the sound pressure levels were compared with commercially available greases.The results are described below. Figure 1 shows the sound pressure level when a sealed ball bearing (6202ZZ) is filled with grease A of the present invention, grease H of comparative example 1, and commercially available greases E to G, and is installed in a small electric motor and rotated in an atmosphere at 120°C. It shows the change over time. The horizontal axis represents rotation time, and the vertical axis represents sound pressure level. As can be seen from FIG. 1, Grease A of Example 1 has a low initial sound pressure level, and the sound pressure level does not become very high even after 1000 hours of rotation. On the other hand, Grease H of Comparative Example 1 has a high initial sound pressure level and cannot be used where low noise is required. Furthermore, commercially available diurea greases E to G not only have a high initial sound pressure level, but also rapidly increase after about 800 hours. In particular, commercially available lithium grease has the disadvantage that although the initial sound pressure level is low, it rises rapidly after about 200 hours. Table 1 shows the initial vibration values A to L when a sealed ball bearing (62022RU) was filled with each of the above greases and operated at room temperature and 1800 rpm.

[Table] FIG. 2 is a graph showing each vibration value A to L in Table 1 above (horizontal axis: type of grease, vertical axis: vibration value). As is clear from Figures 1 and 2, the sound pressure level of the grease of the present invention is lower than that of other greases, and even after long-term use, the sound pressure level is extremely superior to other greases. . In addition, the initial vibration value was also low, especially in Comparative Example 3, in which the additive of the present invention was added to the grease after production.
Greases J to K of Nos. 4 and 5 showed a value of 0.05 G or more, which was significantly higher than the value of each grease of Examples, and no satisfactory effect was observed. In this way, the grease produced by the manufacturing method of the present invention is
It is clear that it has excellent low noise properties and can be used for long periods of time at high temperatures.

[Brief explanation of drawings]

FIG. 1 is a graph showing the relationship between the sound pressure level of various greases and time, and FIG. 2 is a graph showing the relationship between the vibration value of various greases.

Claims (1)

[Claims] 1 An amine compound is dissolved in a lubricating oil, an isocyanate compound is further added thereto together with the lubricating oil as necessary to cause the amine compound and isocyanate compound to react, and then the reaction product is heated to form a diurea grease. A low-noise property characterized by making one or more of alkenylsuccinimide, alkylbenzenesulfonic acid metal salt, and petroleum sulfonic acid metal salt present during the reaction between an amine compound and an isocyanate compound. Manufacturing method for diurea grease.