JPH0332595B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to high quality lithium complex grease compositions with high extreme pressure properties, high dropping points, and long lubrication life.

Traditionally, lithium soap grease has been widely used due to its advantages such as relatively good heat resistance and water resistance, easy dispersion of soap into all types of lubricant bases, and reasonable price. has been used. However, in the case of lithium soap grease, when the usage environment and conditions reach high temperatures of 130°C or higher, the lubricating action of the grease rapidly disappears due to oxidative deterioration, resulting in micelle destruction, decreased adhesion, softening, and increased oil separation. There are some drawbacks.

Non-soap-based greases with extremely high dropping points and various complex greases have been developed as heat-resistant greases that compensate for these shortcomings, but they tend to harden or become extremely soft after long-term use. There are drawbacks such as Moreover, it has drawbacks such as being extremely expensive, and its uses are naturally limited.

On the other hand, the environment in which grease is used is becoming worse as mechanical devices become smaller and operating parts become faster. For example, when bearings for electrical components in automobiles and the like are used in areas that are close to the heat source of an engine, the grease that lubricates the bearings is subjected to particularly high temperature conditions for a long period of time. In such cases, the grease needs to have sufficient high temperature resistance, durability, etc. Additionally, with the development of industry, machines are being operated under higher loads and harsher conditions, and lubricating greases that can withstand these conditions are needed. Currently, large amounts of extreme pressure additives are added to high-load greases in order to meet high-load conditions. However, extreme pressure additives generally have the disadvantage of polluting the environment and being corrosive. For example, among additives with good extreme pressure properties, those containing cadmium, antimony, etc. can no longer be used as poisonous substances. Furthermore, in terms of corrosion, chlorine-based extreme pressure additives tend to rust and corrode iron, steel, etc. at temperatures above 100°C. Many other extreme pressure additives have similar properties.

The purpose of the present invention is to meet the above-mentioned needs.
High temperature resistance, durability, water resistance, extreme pressure resistance (load capacity)
Our objective is to provide excellent high-quality lithium complex grease with the following characteristics.

The above purpose is to add C ₁₂ ~ as a thickener to the base oil.
It has been discovered that this can be achieved with a lithium complex grease obtained by mixing and dispersing three essential components: lithium soap of _C24 hydroxy fatty acid, lithium borate, and zinc salt of boric acid, and the present invention has been achieved. It was completed.

According to the present invention, the following three thickeners are added to the base oil consisting of oil having lubricating viscosity.
An electrode characterized in that the essential components are uniformly mixed and dispersed as essential components, namely (a) lithium soap of C ₁₂ - C ₂₄ hydroxy fatty acid, (b) lithium salt of boric acid, and (c) zinc salt of boric acid. Grease compositions are provided that have pressure properties and high dropping points.

The grease composition provided by the present invention is most distinctive in that it has very high extreme pressure properties based on the combination of the above-mentioned three specific components, and at the same time has a high dropping point, which is an indicator of high temperature resistance. It is.

Hereinafter, the lithium complex grease composition provided by the present invention will be explained in more detail.

Base oil: As the base oil used in the composition of the present invention, any oil having a known lubricating viscosity that has been conventionally used in lubricating oils can be used, and the most typical oil is a refined petroleum product. It is one of the mineral oils, ester oils [e.g. diester oils such as dioctyl sebacate, tetraesters such as pentaerythritol esters of aliphatic monocarboxylic acids (e.g. pentaerythritol tetraamyl ester)],
Polyα-olefin oligomers (e.g. viscosity
41.0cSt/37.8℃, viscosity index 130, pour point -60℃,
octene-1/decene-1 copolymer with a flash point of 223°C), polyglycol oil, silicone oil, polyphenyl ether oil, halogenated hydrocarbon oil,
Synthetic oils such as alkylbenzene oils can also be used alone or in combination with mineral oils.

Here, "oil having a lubricating viscosity" generally has a viscosity of about 2 to 500 cSt at 40°C, preferably about 20 to 500 cSt.
Refers to oil having a viscosity within the range of 200 cSt.

Component (a): The lithium soap added to the base oil according to the invention is selected from lithium salts of _C12 to _C24 hydroxy fatty acids. used in the formation of such lithium salts.
_C12 - _C24 hydroxy fatty acids are usually linear saturated or unsaturated aliphatic monocarboxylic acids having a hydroxyl group in the molecule, and specifically, for example, 2-hydroxydodecanoic acid, 2-hydroxy Tetradecanoic acid, 2-hydroxyhexadecanoic acid, 11-hydroxyhexadecanoic acid, ambretrichic acid, ricinoleic acid, ricinostearolucic acid, 9-hydroxystearic acid, 10-hydroxystearic acid, 12-hydroxystearic acid, etc. Among them, those having 18 carbon atoms and those having a hydroxyl group bonded at the 9-, 10-, or 12-position, especially 12-hydroxystearic acid and ricinoleic acid, are preferred.

Each of the above lithium salts of hydroxy fatty acids can be used alone, or two or more kinds can be used in combination. In addition, when forming the lithium salt from the above-mentioned hydroxy fatty acid, the hydroxy fatty acid can be reacted with lithium hydroxide not only in the form of a free acid but also in the form of a glyceride.

(b) Component: The second component added to the base oil according to the present invention is a lithium salt of boric acid. The lithium salt may be present in the form of lithium metaborate, lithium tetraborate, lithium pentaborate, lithium perborate, etc., or a mixture of two or more thereof.

(c) Component: The third component added to the base oil according to the present invention is a zinc salt of boric acid. This zinc salt may also exist in the form of zinc metaborate, zinc tetraborate, basic zinc borate, etc., or a mixture of two or more of these.

Note that the lithium salt of boric acid and the zinc salt of boric acid may exist in the form of individual salts, or may be used in the form of a lithium-zinc mixed metal salt or composite metal salt of boric acid. Good too. Of course, the latter mixed metal salts and composite metal salts are the same as component (b).
(c) It can be used as an ingredient that simultaneously fulfills the role of an ingredient.

Preparation of grease composition: The grease composition of the present invention is produced by uniformly mixing and finely dispersing the three components (a), (b), and (c) in the base oil described above. can do. The amounts of the three components (a), (b), and (c) in the base oil are not strict and vary depending on the type of each component, but generally the following proportions are used per 100 parts by weight of the base oil. It is advantageous to use (within the preferred range).

(a) Component: 2 to 40 parts by weight (5 to 20 parts by weight) (b) Component: 0.05 to 20 parts by weight (0.1 to 10 parts by weight) (c) Component: 0.05 to 20 parts by weight (0.1 to 10 parts by weight) ) The grease composition of the present invention contains the above (a), (b) and (c).
In addition to these three components, if necessary, conventional lubricating oil additives such as antioxidants (e.g. 2,6-ditar
syabutyl-4-methylphenol, N-phenyl-α-naphthylamine, octylated diphenylamine, etc.), rust inhibitors (e.g. oxidized paraffin,
Aminoimidazoline, calcium dinonylnaphthalene sulfonate, barium dinonylnaphthalene sulfonate, etc.) can also be blended in commonly used amounts.

Next, a general method for producing the grease of the present invention will be described.

In the grease of the present invention, a hydroxy fatty acid to form component (a) is added to a base oil and dissolved at a temperature of 70 to 80°C. Next, approximately equivalent amount of lithium hydroxide to the hydroxy fatty acid is added at 80 to 90°C to produce soap. Then let it cool down a little to 70-80℃
Then, add boric acid to form component (b), and add approximately equivalent amount of lithium hydroxide. moreover,
Add boric acid to form component (c), and add zinc oxide in an approximately equivalent amount. Note that the entire amount of boric acid may be added at once, and then both lithium hydroxide and zinc oxide may be added.
Thereafter, the temperature is raised to 140-150°C while heating and pressurizing, and when the temperature reaches 140-150°C, dehydration is started. After complete dehydration, heat to 195-220°C, then cool to 175-193°C, maintain at that temperature for 10-40 minutes, and then cool.

The lithium complex grease composition provided by the present invention as described above has a very high dropping point and long lubrication life, which are indicators of high temperature resistance, and has high extreme pressure properties, and is extremely effective as a grease. It is of high performance.

The present invention will be further explained below with reference to Examples.

Example 1 Refined mineral oil (paraffin base, viscosity index 102,
Pour point -15℃, kinematic viscosity 44.9cSt at 37.8℃, 98.9℃
6.4cSt) 2463.0g and 270g of 12-hydroxystearic acid are placed in the autoclave No. 5, and heated to 80°C for 30 to 40 minutes while stirring to completely dissolve the 12-hydroxystearic acid. Next, a hot aqueous solution containing 38.5 g of lithium hydroxide (95
℃) and maintain at 90℃ for 5-15 minutes with stirring. It was then cooled to 75°C and diluted with boric acid 44.4
Add 300 g of a hot aqueous solution (95°C) in which g is dissolved and stir to dissolve. After stirring for 5 to 15 minutes, 250 g of a hot aqueous solution (95°C) containing 31.4 g of lithium hydroxide is added and stirred for 5 to 15 minutes. A hot aqueous solution (95℃) in which 44.4g of boric acid was dissolved while maintaining the temperature between 75 and 80℃.
Add 300g and stir to dissolve. After stirring for 5 to 15 minutes, 50g of an aqueous solution (30℃) containing 34.8g of zinc oxide
Add and continue heating gradually while stirring. 145～
Heat slowly to 150°C over about 1 to 1.5 hours, pressurize, and when the same temperature is reached, open the autoclave and dehydrate at the same temperature for 15 to 25 minutes. After the dehydration is complete, the contents of the autoclave are heated to 205~
Heat to a temperature of 220 ° C, then 185 ° C while stirring
Cool to ˜192° C. and maintain this temperature for 20-30 minutes before further cooling and when about 160° C. add 60 g of antioxidant. Continue stirring for an additional 30-60 minutes until the temperature drops to about 85°C, then process with a Manton-Goring type homogenizer.

The properties of the grease composition thus obtained were as follows.

Stability ^*1 (immiscible) 275 (mixed 60 times) 285 Shell roll test ^*2 (100℃×5h) Before test: 138 After test: 184 Difference: +46 Dropping point (℃) ^*1 : 261 Oil separation degree ^*1 (100°C x 24h): 3.0% Heated copper plate corrosion test ^*1 (100°C x 24h): Passed Shell 4-ball test ^*3 Fusion load (Kg): 316 Initial seizure load (Kg): 79 Average hertz Load (Kg): 43.2 *1 According to JIS K 2220.

*2 Roll safety according to ASTM D 1831 Determination test.

*3 According to IP 239.

Example 2 In order to increase the amount of lithium borate and zinc borate in the grease prepared in Example 1 by one and a half times, 66.6 g of boric acid, 47.6 g of lithium hydroxide, and 47.6 g of lithium hydroxide were added to form lithium borate. A grease composition was prepared in the same manner as in Example 1, except that 66.6 g of boric acid and 52.2 g of zinc oxide were used to form zinc oxide, and 2385 g of refined mineral oil were used.

The properties of the obtained grease composition were as follows.

Stiffness (immiscible): 281 (mixed 60 times): 292 Shell roll test (100℃ x 5h) Before test: 141 After test: 179 Difference: +38 Dropping point (℃): 251 Shell 4-ball test Fusion Load (Kg): 355 Example 3 In order to change the composition of zinc borate in the grease prepared in Example 1, 44.4 g of boric acid and 39.0 g of zinc oxide were used to form zinc borate, and refined mineral oil was added. A grease composition was prepared in the same manner as in Example 1, except that 2458.8 g of .

The properties of the obtained grease composition were as follows.

Stiffness (immiscible): 288 (mixed 60 times): 293 Shell roll test (100℃ x 5h) Before test: 144 After test: 182 Difference: +38 Dropping point (℃): 253 Shell 4-ball test Fusion Load (Kg): 316 Example 4 In order to change the composition of zinc borate in the grease prepared in Example 1, 44.4 g of boric acid and 58.5 g of zinc oxide were used to form zinc borate, and refined mineral oil was added. A grease composition was prepared in the same manner as in Example 1, except that 2439.3g of .

The properties of the obtained grease composition were as follows.

Stiffness (immiscible): 292 (mixed 60 times): 300 Shell roll test (100℃ x 5h) Before test: 146 After test: 189 Difference: +43 Dropping point (℃): 245 Shell 4-ball test Fusion Load (Kg): 355 Example 5 In order to change the composition of zinc borate in the grease prepared in Example 1, 44.4 g of boric acid and 78 g of zinc oxide were used to form zinc borate, and refined mineral oil was added. A grease composition was prepared in the same manner as in Example 1 except that 2419.8g was used.

The properties of the obtained grease composition were as follows.

Stiffness (immiscible): 298 (mixed 60 times): 317 Shell roll test (100℃ x 5h) Before test: 150 After test: 190 Difference: +40 Dropping point (℃): 232 Shell 4-ball test Fusion Load (Kg): 355 Initial baking load (Kg): 112 Average Hertzian load (Kg): 54.8 Comparative example 1 The properties of a commercially available general-purpose lithium 12-hydroxystearate soap grease that does not contain extreme pressure additives are as follows. It was hot.

Stiffness (immiscible): 272 (mixed 60 times): 273 Shell roll test (100℃ x 5h) Before test: 137 After test: 168 Difference: +31 Dropping point (℃): 180 Shell 4-ball test Fusion Load (Kg): 200 Initial Seizure Load (Kg): 63 Average Hertzian Load (Kg): 29.6 Comparative Example 2 Commercially available lithium 12-hydroxystearate soap grease containing sulfide and lead compounds as extreme pressure additives. The properties were as follows.

Degree of purity (immiscibility): 282 (mixed 60 times): 276 Shell roll test (100℃ x 5h) Before exam: 141 After exam: 180 Difference: +39 Dropping point (℃): 184 Ciel 4-ball test Fusion load (Kg): 355 Initial seizure load (Kg): 89 Average Hertz load (Kg): 47.8

Claims (1)

[Scope of Claims] 1. A base oil consisting of an oil having a lubricating viscosity and the following three components as thickeners, namely (a) lithium soap of C ₁₂ - C ₂₄ hydroxy fatty acid (b) lithium of boric acid A grease composition having extreme pressure properties and a high dropping point, characterized by uniformly mixing and dispersing a salt and (c) a zinc salt of boric acid as essential components.