JP2001115181A - Grease composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a grease composition which is capable of satisfying the water resistance, heat resistance, mechanical stability, wear resistance and extreme-pressure resistance at the same time, especially of improving the friction reduction considerably. SOLUTION: This grease composition comprises a base oil as the main material, which is added with 11-16.5 wt.% of an alicyclic diurea expressed by chemical formula 1, 1-5 wt.% of molybdenum dithiocarbamate, 0.5-4 wt.% of zinc dithiophosphate and 1-5 wt.% of antimony dithiocarbamate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grease composition, and more particularly, to a base oil comprising a base oil and 4,4'-diphenylmethane diisocyanate as a thickener.
By adding alicyclic diurea obtained by the reaction of (MDI) with cyclohexylamine as a specific content and simultaneously containing appropriate amounts of molybdenum dithiocarbamate, zinc dithiophosphate and antimony dithiocarbamate as additives. Unlike the grease composition of the present invention, the grease composition can simultaneously satisfy water resistance, heat resistance, mechanical stability, abrasion resistance and extreme pressure properties, and particularly can significantly improve friction reduction. is there.

[0002]

2. Description of the Related Art Grease is used for the purpose of assisting effective lubrication of constant velocity joints for preventing wear of automobiles. Generally, grease is used for thickening agents and extreme pressure agents for the purpose of recycling. It is manufactured by adding At this time, the thickener used in the grease composition serves to impart a specific Newton property to the grease to maintain it in a semi-solid state, and the physical and chemical properties vary greatly depending on the type of the thickener. The choice of the thickener is very important. Examples of the above thickener include a metal soap thickener and a urea thickener.

Here, a grease composition using the above metal soap thickener containing a metal component may cause the metal component of the metal soap thickener to act as a catalyst for causing oxidation and corrosion. In addition, there is a problem that the oxidation stability and the thermal stability of the grease composition are reduced.

[0004]

On the other hand, when the urea thickener is contained in the grease composition, the urea thickener does not contain a metal component. Excellent thermal stability and oxidation stability can be obtained as compared with the grease composition. The urea thickener,
Generally, it can be obtained by reacting amines with a functional group of diisocyanate, and the types thereof are various. Examples of the urea thickener include diurea, triurea, tetraurea, and polyurea. From diurea, aliphatic urea, alicyclic diurea, and aromatic urea are widely used. Grease compositions using the above diurea, triurea, tetraurea, polyurea and the like as thickeners are already known [see US Pat. Nos. 5,033,085 and 4,915,860]. However, according to the above patent, no mention is made of the specificity of the alicyclic diurea used as a thickener. Further, the urea thickener has better thermal stability and oxidative stability than the metal soap thickener, but does not satisfy the performance required for automotive grease because of poor friction characteristics and water resistance. It is. Under such circumstances, the development of a urea thickener that solves problems relating to friction characteristics and water resistance required for automotive grease is urgently required.

Accordingly, the present invention specifies an alicyclic diurea obtained by reacting 4,4'-diphenylmethane diisocyanate (MDI) with cyclohexylamine as a thickener based on a base oil. At the same time as the content
An appropriate amount of molybdenum dithiocarbamate as an additive,
By including zinc dithiophosphate and antimony dithiocarbamate, unlike conventional grease compositions, water resistance, heat resistance, mechanical stability, abrasion resistance and extreme pressure resistance can be simultaneously satisfied, and especially friction. It is an object to provide a grease composition that can significantly improve the reduction.

[0006]

According to the present invention, there is provided a base oil comprising 11 to 16.5% by weight of alicyclic diurea and 1 to 5% by weight of dithiocarbamine represented by the following chemical formula 1. A grease composition comprising molybdenum acid, 0.5 to 4% by weight zinc dithiophosphate and 1 to 5% by weight antimony dithiocarbamate is characterized. Chemical formula 1

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[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail as follows. The present invention includes, as a thickener, an alicyclic diurea, which is a type of diurea among ureas, in order to maximize the properties such as thermal stability and oxidation stability of existing urea-based grease compositions. At the same time, it relates to a grease composition containing a suitable amount of an additive and an extreme pressure agent. First, the grease composition according to the present invention has a base oil as a main material.
It is desirable to use one having a viscosity of 14.5 to 16.5 cst. Further, the present invention, in order to most improve the physical properties such as thermal stability and oxidation stability of the existing urea-based grease composition, among the urea as a thickener alicyclic diurea, which is a type of diurea. The biggest feature is that it is included as a thickener.

The alicyclic diurea is obtained by reacting 4,4'-diphenylmethane diisocyanate (MDI) with cyclohexylamine in a base oil. The cycloaliphatic diurea produced in this way has a ratio of 1 to the total grease composition.
It is desirable to include it as 1 to 16.5% by weight. If the content of the thickener is less than 11% by weight, the viscosity (a measure of grease hardness: KSM2032) becomes high, and the separation of oil proceeds, which is not desirable. On the other hand, if the content exceeds 16.5% by weight, the fluidity decreases, which is not desirable.

The grease composition of the present invention contains molybdenum dithiocarbamate as an additive to the entire grease composition in order to effectively prevent the grease composition from being worn.
If the content is less than 1% by weight, the desired effect of preventing wear cannot be obtained. On the other hand, if it is used in excess of 5% by weight, the effect is the same or worse as compared with conventional grease compositions, which is not desirable.

The grease composition of the present invention contains, as another additive, 0.5 to 4% by weight of zinc dithiophosphate, which has an increasing effect similarly to molybdenum dithiocarbamate, based on the whole grease composition. Preferably, it is contained as 1.5 to 3% by weight.
If the content is less than 0.5% by weight, the wear resistance is reduced. On the other hand, if it is used in excess of 4% by weight, its effect is almost the same as that of a conventional grease composition, and therefore it is not desirable.

Further, in the present invention, it is desirable that antimony dithiocarbamate is contained as an extreme pressure additive and an antioxidant in an amount of 1 to 5% by weight based on the whole grease composition, more preferably 2.5 to 5% by weight. 3.5% by weight. When the content is less than 1% by weight, the extreme pressure property and the antioxidant effect decrease. On the other hand, if it is used in an amount exceeding 5% by weight, the effect is almost the same as that of the conventional grease composition, so that an improved effect cannot be expected.

[0012] In addition, the grease composition of the present invention uses, for example, an anticorrosion additive, an adhesion enhancer, and a copper plate corrosion inhibitor which are usually added when producing the grease composition.
Therefore, the grease composition according to the present invention satisfies the physical properties such as water resistance and mechanical stability at the same time as the conventional grease composition, and has an effect of being used as an automobile grease with remarkably reduced friction reducing property.

[0013]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. (Production example: production of alicyclic diurea grease) 1 mol of 4,
When 4'-diphenylmethane diisocyanate (MDI) and 2 moles of cyclohexylamine were dissolved in a base oil and stirred at 100 ° C for 1 hour, they were dispersed to form an alicyclic diurea grease.

Examples 1 and 2 and Comparative Examples 1 to 4 Grease compositions were prepared according to the compositions and contents shown in Table 1 below. At this time, the alicyclic diurea produced by the above Production Example was used as a thickener. Further, the physical properties of the grease composition were measured by the methods described below, and the results are shown in Table 1. Admix viscosity: Calculated by the KSM2032 method to measure fluidity. 4-point extreme pressure test: Calculated by ASTM D2596 method to measure extreme pressure. 4-point wear test: ASTM to measure wear resistance
It was calculated by the D2266 method. Stability of water mixing: Calculated by the KSM2051 method to measure water resistance. Dropping point: Calculated by the KSM2033 method to measure heat resistance. Coefficient of friction: Calculated according to ASTM D5183 method to measure friction reduction.

[0015]

[Table 1]

[0016]

As described above, the grease composition of the present invention has a great effect on abrasion resistance and friction reduction, and has extremely excellent water miscibility as well as extreme pressure resistance and heat resistance. It is useful even under severe conditions where water comes into contact with constant velocity joints of automobiles that require characteristics.

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Claims (2)

[Claims] 1. An alicyclic diurea containing a base oil as a base material and containing 11 to 16.5% by weight of an alicyclic diurea represented by the following chemical formula 1.
5% by weight molybdenum dithiocarbamate, from 0.5 to
A grease composition comprising 4% by weight of zinc dithiophosphate and 1 to 5% by weight of antimony dithiocarbamate. Chemical formula 1 2. The method according to claim 1, wherein the alicyclic diurea is obtained by reacting 4,4′-diphenylmethane diisocyanate (MDI) with cyclohexylamine.
Grease composition.