JPH10121080A - Urea grease composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a urea grease composition being excellent in friction characteristics and nonabrasiveness and not causing deterioration of a seal material by mixing a urea grease with two specified compounds as additives. SOLUTION: A urea grease is mixed with a sulfided molybdenum dialkyldithiocarbamate (A) represented by formula I (wherein R<1> and R<2> are each a 1-24C alkyl; m+n=4; m is 0-3; and n is 4-1) and a triphenyl phosphate (B) represented by formula II. Component A is in the form of a powder and is used in an amount of 0.5-10wt.% based on the entire weight. Component B is in the form of a normally solid powder having a melting point of 50 deg.C and is used in an amount of 0.1-10wt.% based on the entire weight of the base grease. The urea compound used as a thickening agent may be of any type and is exemplified by urea or tirurea. The base oil used comprises a mineral oil and/or a synthetic oil, and the urea compound as a thickening agent is used in an amount of 2-35wt.% based on the total weight of the base oil and the urea compound. The obtained mixture is further mixed with various additives such as an antioxidant, a rust preventive, an extreme pressure agent and a polymer to obtain a urea grease composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urea grease having excellent frictional properties and abrasion resistance and excellent sealing properties such as chloroprene rubber and polyester resin, and more particularly to a constant velocity joint, a ball joint and a wheel of an automobile. The present invention can be applied to lubrication points of bearings, gears, etc. in various industrial facilities such as bearings and steel, industrial machines, machine tools, and the like.

[0002]

2. Description of the Related Art Since the oil crisis, soaring oil prices have led to the establishment of resource-saving and energy-saving orientations in various industries, strongly reflecting the impact.

[0003] In the automobile industry, general passenger cars have been reduced in size and weight, and with the adoption of FFs, constant velocity joints (Constant Velocity Join) have been developed.
Vehicles that use CVJs (hereinafter, abbreviated as CVJ) are increasing. The demand for CVJs has also been increasing in 4WD vehicles and 4-wheel independent suspension FR vehicles. CVJ is
Also known as a constant velocity universal joint, it is a joint that transmits rotation while maintaining the same angular velocity and torque, and has various types. The lubricant used depends on the purpose of use, but with the recent increase in the output and speed of automobiles and the weight reduction of the CVJ itself, it has become even more severe, and greases that reduce friction and wear of sliding parts have been developed. Required. Also,
It is necessary to attach a seal boot material to CVJ to prevent grease from leaking and to prevent foreign substances and water from entering. As this material, chloroprene rubber is most commonly used, but polyester resin is also used. Many are used.

[0004] Grease having low friction and excellent wear resistance is
Suppresses vehicle body vibration and noise during vehicle acceleration and running. Although the durability of the seal boot material can be improved due to its temperature suppressing effect, an excessive rise in temperature promotes the aging of the seal boot material and the deterioration of the lubricant, and significantly impairs the life of the CVJ.

[0005] On the other hand, in the steel industry, continuity of machinery and equipment has been further promoted along with technological innovation, and there is a strong demand for higher quality of products, improvement of production process capability, assurance of equipment reliability, and the like. The grease used in these machinery and equipment is under adverse environments such as high heat, contact with water, and the possibility of foreign matter intrusion such as scales. Very strict. In order to prolong the life of mechanical parts and prevent catastrophic failures,
There is a demand for a grease that reduces abrasion and has excellent sealing resistance. In addition, lubrication points of industrial machines, machine tools, and the like have high friction and wear progresses, and the precision of the machine decreases, so that machine parts must be replaced. Thus, reducing friction and preventing wear are also important issues in this application.

For this reason, in the lubricating parts described above, sulfur-based materials such as sulfurized oils and fats and sulfurized olefins, lead naphthenate,
Lithium-based greases using metal dithiophosphate, metal dithiocarbamate-based additives and the like have been used. In recent years, the use of lithium complex grease or urea grease, which has better heat resistance than lithium-based grease, has been increasing.

As a typical prior art in such a situation, US Pat. No. 4,514,312 discloses a grease using an aromatic amine phosphate as an organic additive not containing sulfur in urea grease. . Further, the technology of US Pat. No. 4,840,740 discloses a grease in which an organic molybdenum compound and zinc dithiophosphate are used in combination with urea grease. 4-34
No. 590 discloses a urea grease comprising one or more members selected from the group consisting of sulfurized molybdenum dialkyldithiocarbamates, sulfurized oils and fats, sulfurized olefins, tricresyl phosphate, trialkylthiophosphates, and zinc dialkyldithiophosphates. It contains a sulfur-phosphorus extreme pressure additive consisting of a combination as an essential component.

However, some of these greases in the prior art have a friction and wear reduction effect, but are not yet satisfactory. There is also a disadvantage that the sealing material is deteriorated at a high temperature. For example,
Amaromatic amine phosphate and lead naphthenate have the disadvantage that polyester resins and sulfide oils and fats, respectively, deteriorate chloroprene rubber, and sulfurized olefins have the disadvantage that both chloroprene rubber and polyester resins are significantly deteriorated.

As another prior art, a technique using molybdenum sulfide dialkyldithiocarbamate and triphenylphosphorothionate as additives is disclosed in Japanese Patent Application Laid-Open No. Hei 8-157589, and 1 thickener is used as a thickener.
Lithium soaps of 2-hydroxy fatty acids, lithium phosphates formed from phosphate esters such as triethyl phosphate and triphenyl phosphate and dilithium borate are described in JP-A-62-275197, respectively. ing. Further, a grease composition using a phosphate ester oil as a urea compound is described in JP-A-3-231993.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a urea grease composition which has excellent friction characteristics and abrasion resistance and does not deteriorate a sealing material. The point is to provide things.

[0011]

The present invention relates to urea grease as an additive (A)

Embedded image (Wherein, R ¹ and R ² are each independently selected from the group consisting of alkyl groups having 1 to 24 carbon atoms, and m + n =
4, and m is from 0 to 3, and n is from 4 to 1), and a molybdenum sulfide dialkyldithiocarbamate represented by the formula:
(B) formula

Embedded image And triphenyl phosphate represented by the formula (1):

The (A) molybdenum sulfide dialkyldithiocarbamate is a compound having a high melting point, and examples thereof include diethyl sulfide-molybdenum dithiocarbamate, dibutyl sulfide-molybdenum dithiocarbamate, diisobutyl sulfide-molybdenum dithiocarbamate, and sulfurized molybdenum. Molybdenum di (2-ethylhexyl) -dithiocarbamate, molybdenum diamil-dithiocarbamate, molybdenum diisoamyl-dithiocarbamate, molybdenum dilauryl-dithiocarbamate, molybdenum disulfide-dithiocarbamate, n-butyl sulfide, 2-ethylhexyl-dithiocarbamate Molybdenum and the like can be mentioned, and these are
All are mixed in the form of a powder, but the amount of addition is 0.5 to 10% by weight, preferably 0.5 to 5% by weight based on the total amount.
It is. When the amount is less than 0.5% by weight, the effect of improving the friction resistance and the abrasion resistance is insufficient, and when it exceeds 10% by weight, the effect is not further increased.

The triphenyl phosphate (B) has a melting point of 50 ° C.
The powder can be blended with a base grease at 50 ° C. or higher at the time of compounding.
The amount used is 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the total amount. If the amount is less than 0.1% by weight, no improvement in friction and wear characteristics is observed, and even if the amount exceeds 10% by weight, more satisfactory lubricating performance cannot be exhibited.

As the urea compound used as the thickener, any of the known urea-based thickeners can be used, and the type thereof is not particularly limited. For example,
Examples thereof include diurea, triurea, and tetraurea.

As the base oil, mineral oil and / or synthetic oil is used. The urea compound as a thickener can be used in an amount generally ranging from 2 to 35% by weight based on the total amount of the base oil and the urea compound.

Further, various additives such as an antioxidant, a rust inhibitor, an extreme pressure agent, and a polymer can be added to the composition of the present invention.

[0017]

Examples and Comparative Examples The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Additives were added to the base grease at the compounding ratios shown in Tables 1 to 5 (all are shown by weight%), and the mixture was treated with a three-roll mill to obtain greases of Examples and Comparative Examples. The composition of the base grease is as follows. As the base oil, a purified mineral oil having a viscosity at 100 ° C. of 15 mm ² / sec was used.

I. Diurea grease One mole of diphenylmethane-4,4'-diisocyanate and 2 moles of octylamine were reacted in a base oil, and the resulting urea compound was uniformly dispersed to obtain a grease. The content of the urea compound was used so as to be 10% by weight based on the total amount of the base oil and the urea compound.

II. Tetraurea grease In a base oil, 2 mol of diphenylmethane-4,4'-diisocyanate was reacted with 2 mol of octylamine and 1 mol of ethylenediamine, and the resulting urea compound was uniformly dispersed to obtain a grease. The content of the urea compound is 15% by weight based on the total amount of the base oil and the urea compound.
It was used to be.

III. Lithium complex grease Castor oil-hardened fatty acid was dissolved in base oil, and an aqueous solution of lithium hydroxide necessary for neutralization was added, and dehydration was performed while performing the reaction. After the dehydration was completed, azelaic acid was further added, and a reaction was carried out using a neutralized equivalent of an aqueous solution of lithium hydroxide. The produced lithium azelate and lithium 12-hydroxystearate soap were uniformly mixed and dispersed to obtain a grease. The soap content was 7.5% by weight of lithium 12-hydroxystearate and 2.5% by weight of lithium azelate as the thickener, based on the total amount of the base oil and the thickener.
It was used so that it might become the weight%.

The following tests were performed to evaluate the friction coefficient, wear resistance and compatibility with the sealing material in the table.

(1) Coefficient of friction Using a Falex tester, the coefficient of friction after 15 minutes was determined under the following conditions (based on IP 241/69). Rotational speed: 290 rpm Load: 200 lb Temperature: room temperature Time: 15 minutes Grease amount: About 1 g of grease is applied to the test piece

(2) Abrasion resistance Four-ball wear test According to ASTM D2226. Number of rotations: 1200 rpm Load: 40 kgf Temperature: 75 ° C Time: 60 minutes

(3) Compatibility with Sealing Material According to the vulcanized rubber physical test of JIS K6301, when the sealing material is chloroprene rubber or polyester resin, it is immersed in each grease composition under the following conditions. Tested. Before and after the test, the tensile strength and elongation after the test were measured, and the respective rates of change were determined. Temperature: 140 ° C Immersion time: 96 hrs

[0025]

[Table 1] * ¹ : A-1 is molybdenum sulfide dialkyldithiocarbamate and is MOLYVAN A manufactured by Vanderbilt. * ² : A-2 is molybdenum sulfide dialkyldithiocarbamate, Sakura Lube 600 manufactured by Asahi Denka Kogyo Co., Ltd. * ³ : B is triphenyl phosphate.

[0026]

[Table 2]

[0027]

[Table 3] * ¹ : A-1 is molybdenum sulfide dialkyldithiocarbamate and is MOLYVAN A manufactured by Vanderbilt. * ² : A-2 is molybdenum sulfide dialkyldithiocarbamate, Sakura Lube 600 manufactured by Asahi Denka Kogyo Co., Ltd. * ³ : B is triphenyl phosphate. * ⁴ : Vanlube 692 is R.R. T. Vanderbilt Co. Inc. Is a viscous liquid (190SUS / 100 ° C) composed of aromatic amine phosphate. * ⁵ : Lubrizol 1360 is zinc dialkyldithiophosphate. * ⁶ : Lubrizol 5006 is a sulfurized oil and fat. * ⁷ : Lubrizol 5340L is a sulfurized olefin.

[0028]

[Table 4]

[0029]

[Table 5]

[0030]

[Table 6]

[0031]

[Table 7]

[0032]

[Table 8]

[0033]

[Evaluation] The friction coefficients of Examples 1 to 7 were all smaller than those of Comparative Examples 1 to 10, and good results were obtained. With respect to the abrasion resistance, Comparative Examples 5, 6, 7, 9 and 10 give the same good results as the examples. However, these comparative examples are inferior in compatibility with chloroprene rubber or polyester resin. For example, in Comparative Example 5, the chloroprene rubber and the polyester resin have large elongation change rates. In Comparative Example 6, the tensile strength and elongation change of the chloroprene rubber were large. In Comparative Example 7, the tensile strength and elongation change of the chloroprene rubber and the polyester resin are remarkably large. In Comparative Examples 9 and 10, the rate of change in elongation of the polyester resin was slightly large. It is clear that Examples 1 to 7 are excellent in friction coefficient and abrasion resistance, and also excellent in compatibility with chloroprene rubber and polyester resin sealing materials. In addition, Comparative Examples 1 to 3 contain one of the additives of the present invention, and thus show some very good results in terms of the rate of change, but are inferior in terms of friction coefficient and abrasion resistance.

[0034]

【effect】

(1) The grease of the present invention has a low coefficient of friction and excellent wear resistance. As a result, vibration and noise of the constant velocity joint of the vehicle are suppressed. In addition, wear of ball joints, wheel bearings and other industrial machinery of automobiles can be reduced, and the life of mechanical parts can be improved. (2) The grease of the present invention has excellent compatibility with chloroprene rubber and polyester resin, and delays the deterioration of the sealing material of the sealing device even at high temperatures.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI (C10M 169/06 115: 08 139: 00 137: 04) C10N 10:12 30:00 30:06 40:02 40:04 50:10 ( 72) Inventor Ryuichi Masumori 3-2-5 Kasumigaseki, Chiyoda-ku, Tokyo Showa Shell Sekiyu KK

Claims (3)

[Claims] (1) Formula (A) as an additive to urea grease: (Wherein, R ¹ and R ² are each independently selected from the group consisting of alkyl groups having 1 to 24 carbon atoms, and m + n =
4, and m is from 0 to 3, and n is from 4 to 1), and a molybdenum sulfide dialkyldithiocarbamate represented by the formula:
(B) Formula And a triphenyl phosphate represented by the formula: 2. The urea grease composition,
(A) 0.5 to 10% by weight, (B) 0.1 to 10% by weight
The urea grease composition according to claim 1, wherein 3. The urea grease composition according to claim 1, wherein the urea compound as a thickener is 2 to 35% by weight based on the total amount of the base oil and the urea compound.