JPH01170692A - Lithium grease composition - Google Patents

Abstract

PURPOSE:To obtain a grease, having a high dropping point, fretting resistance and acoustic characteristics in addition to heat, water resistance and durability, by blending a thickener system containing specific two kinds of Li soaps and monolithium borate as a thickener with a lubricating base oil. CONSTITUTION:The aimed grease obtained by blending 2-30wt.% thickener system containing (A) a lithium soap of a 12-24C dihydroxy fatty acid, (B) lithium soap of a 10-34C fatty acid and (C) monolithium borate as a thickener with a lubricating base oil. The fatty acid is contained in an amount of 0.1-9 pts.wt. based on 1 pt.wt. dihydroxy fatty acid and the dihydroxy fatty acid is contained in an amount of 3-100 pts.wt. based on 1 pt.wt. boric acid.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention has the properties of a high-quality lithium complex grease with a high perfect score, excellent oxidation stability, and long lubrication life, but also has better fretting resistance and good grease properties. The present invention relates to a grease having acoustic characteristics.

PRIOR ART AND PROBLEMS TO BE SOLVED BY THE INVENTION Lithium greases are popular in the market due to their heat resistance, water resistance, and ease of dispersing soap into all types of lubricant bases.
It has a market share of more than 0%.

However, operating machines and equipment at high temperatures, or
Grease usage conditions are becoming harsher due to operations at high speeds and under heavy loads.

Therefore, there are many applications where the performance of ordinary lithium grease is insufficient, and demands for grease that can withstand higher temperatures and have a longer lifespan are diversifying.

The limit temperature for continuous use of normal lithium grease is 12
The temperature ranges from 0°C to 130°C, and when the temperature exceeds 150°C, the lubricity of the grease is lost due to oxidative deterioration, which causes the destruction of micelles, softening of the grease, and increased oil separation.

Current automobiles, electric motors, steel machinery, and other industrial machinery,
The operating temperature for grease lubricated parts of equipment is 150℃.
In many cases, there is a demand for an excellent high-temperature grease.

For example, in automobiles equipped with disc brakes, wheel bearing grease is at risk of being exposed to temperatures of 150 to 200 degrees Celsius due to thick friction heat caused by brake operation. There is a drawback that there is a possibility that the lubricant may flow out or deteriorate rapidly due to oxidation, resulting in poor lubrication.

In addition, in recent years, industrial machinery has become smaller and softer,
Vibration problems occur, and fretting wear in bearings and operating parts due to the vibration of the machine itself becomes a problem, and countermeasures are desired. Furthermore, electrical products, especially audio products, etc., have the problem of bearing noise, and it is desired from the performance standpoint of grease to reduce the noise from the bearings as much as possible.

Conventionally known complex greases containing lithium borate are disclosed in Japanese Patent Publication No. 54-2205 and Japanese Patent Application No. 57-4.
It is disclosed that a high dropping point grease can be made from lithium 12-hydroxystearic acid soap and monolithium borate, as shown in US Pat. No. 7,235. However, the present inventors have investigated a complex grease consisting of sodium 9,10-dihydroxystearate soap and lithium borate; The complex grease of to-dihydroxystearate lithium soap and lithium borate has a significantly lower consistency than the complex of 12-hydroxystearate lithium salt and lithium borate. The former is 0 in terms of soap amount.
It turns out that only No. 1 can be obtained.

In order to meet the above-mentioned needs, the purpose of the present invention is to utilize the excellent performance of lithium grease such as heat resistance, durability, and water resistance, and to have the performance of a lithium complex grease with a high dropping point, as well as fretting resistance and acoustic properties. The purpose is to provide good grease.

The present invention uses (a
) A lithium soap of C12 to C14 dihydroxy fatty acids, (b) a lithium soap of C10 to Csa fatty acids, and (c) monolithium borate are mixed and dispersed as an essential component. It has been discovered that the above object can be achieved by the lithium complex grease obtained by the method, and the present invention has been completed.

Means for Solving the Problems The present invention includes the following ingredients as a thickener in a base oil consisting of a lubricating oil: (a) lithium soap of C12-Cta dihydroxy fatty acid; (b) Cl0-C3, Fatty acid lithium salt, (c)
2 to 30% by weight of a thickener system having monolithium borate, and a fatty acid content of 0.1 to 9% by weight per part by weight of dihydroxy fatty acid.
part by weight, and cyhydroxy fatty acid in a proportion of 3 to 100 parts by weight per part by weight of boric acid.

The objective is to create a complex grease that has a high reversal yield, high dropping point, lubricity, mechanical stability, and long bearing life, as well as good fretting resistance and acoustic properties. is to provide.

The dihydroxy fatty acids used in the preparation of the grease of the invention are selected from lithium salts of C11-C14 dihydroxy fatty acids.

clt-Ct4 hydroxyl fatty acids are usually straight-chain saturated aliphatic monocarboxylic acids having two hydroxyl groups in the molecule, such as dihydroxylauric acid, dihydroxymyridinic acid, and 9,10-dihydroxystearic acid. , dihydroxybehenic acid, etc.9. lO
-dihydroxystearic acid is preferred.

The lithium salts of dihydroxy fatty acids can be used alone or in combination of two or more.

In addition, CIO to C34 fatty acids are linear saturated or unsaturated aliphatic monocarboxylic acids, such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, behenic acid, etc. , stearic acid and oleic acid are preferred.

Lithium salts of fatty acids can be used alone, or two or more kinds can be used in combination.

Further, the base oil used in the composition of the present invention may be a conventional mineral oil,
It may be either a synthetic hydrocarbon oil or a synthetic ester oil, such as ester oils such as dioctyl sebacate, pentaerythritol esters of aliphatic monocarboxylic acids,
Polyα-olefin oligomers (octene-17decene-l copolymer, etc.) polyglycol oil, silicone 40
Synthetic oils such as , polyphenyl ether ura, halogenated hydrocarbon oil, alkylbenzene oil can also be used alone or
Can be used in combination with mineral oil. and it is an oil having a viscosity in the range of about 2 to 500 cSt, preferably about 20 to 200 cSt at 40°C for boat fishing.

The grease of the present invention contains 2 to 30% by weight of a thickener;
Preferably, the content is 5 to 20% by weight.

In the essential components (a), (b) and (C) of the thickener, the fatty acid content is 0.0% per part by weight of dihydroxy fatty acid.
1 to 9 parts by weight, preferably 0.2 to 6 parts by weight, and the dihydroxy fatty acid is 3 to 10 parts by weight per 1 part by weight of boric acid.
0 parts by weight, preferably 5 to 80 parts by weight. If the above-mentioned components (a), (b) and (C) are outside the above-mentioned ranges, a grease having desired properties cannot be obtained.

EXAMPLES Next, the present invention will be explained with reference to examples, but the present invention is not limited thereto.

Refined mineral oil (paraffin base, viscosity index 96, kinematic viscosity 40°C, 104.9 cs) with the blending ratio of raw materials shown in Table 1.
t, 100°C, 11.50cSL, pour point -12,
The entire amount of 172 and 9.1 G-dihydroxystearic acid and stearic acid (5°C) was added and heated to a temperature sufficient to melt the dihydroxy fatty acid and the fatty acid (80°C). Boric acid and lithium hydroxide-hydrate were then added together as aqueous solutions and the resulting mixture was heated with stirring to a final temperature of 200-220<0>C. The remaining refined mineral oil was then added and the mixture was cooled to ambient temperature and processed into a grease using a Manton-Goring type homogenizer.

The α-olefin oligomer base oil has a viscosity index of 132, a kinematic viscosity of 40°C, 31.6 cSt, and 100°C - 5,87 cSt.
It is.

Consistency, dropping point, shell roll test (
The results of the fretting test (room temperature, 150°C) and the acoustic test are shown in Table 1.

From Table 1, it was found that the lithium complex grease of the present invention had a high dropping point, good performance such as heat resistance, durability, and water resistance, and also good fretting resistance and acoustic performance.

The measurement methods for the items in Table 1 are as follows.

Consistency ・JIS K2220 5.3
Dropping point: JIS K2220 5
．． 4-El Roll Test: ASTM D 1831 Fretting Test: AST! 11 D 4170 acoustic test, measured by the method described in Japanese Patent Publication No. 53-2357 As a practical example, the same formulation as practical example 4 in Table 1 was further used.
An antioxidant and a rust preventive agent were added to this to make a grease.Table 2 shows the results of comparing the properties with commercially available lithium complex grease.

It was found that the grease of the present invention has a high dropping point, has properties comparable to those of commercially available greases, such as lubricity, mechanical stability, and high-temperature life, and is also excellent in fretting resistance and acoustic properties.

The measurement methods for the items in Table 2 are as follows: Copper plate corrosion JIS K 2220 5.5B evaporation amount
JIS K 2220 5.613 Oil separation degree J
IS K 2220 5.7 Oxidation Stability JIS
K 2220 5.8 Washing water resistance: jls
K 2220 5.11 Wet
JIS K 2220 5.12 bearing performance test
: ASTM D 1741 Effects of the Invention The lithium grease composition of the present invention has the properties of a high-quality lithium complex grease with a high dropping point, excellent oxidation stability, and long lubrication life, but also has better fretting resistance and This grease has good acoustic properties.

Claims (1)

[Scope of Claims] A base oil consisting of a lubricating oil with the following components as a thickener: (a) C_1_2 to C_2_4 dihydroxy fatty acid lithium soap; (b) C_1_0 to C_3_4 fatty acid lithium soap;
(c) monolithium borate, containing 2 to 30% by weight of a thickener system having 0.1 to 9 fatty acids per part by weight of dihydroxy fatty acid;
parts by weight, and cyhydroxy fatty acid in a proportion of 3 to 100 parts by weight per part by weight of boric acid.