JPS59199798A - Lithium soap grease having high dropping point - Google Patents

Abstract

PURPOSE:To attain a novel lithium soap grease, having a high dropping point, containing a thickener obtained from a hydroxy fatty acid as a starting raw material in a base oil, having little change in consistency at high temperatures, and having improved shear stability, water resistance and oxidative stability. CONSTITUTION:A lithium soap grease, having a high dropping point, and containing a hydroxy fatty acid having boric acid or phosphoric acid linked to the hydroxyl groups and lithium linked to the carboxyl groups and glycerol ester linking parts as a thickener in a mineral or synthetic base oil is attained. EFFECT:Having mixing stability and little oil separation degree.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lithium soap grease with a high dropping point, which is a novel high-quality lithium soap grease that exhibits little change in consistency at high temperatures and also maintains excellent oxidation stability and water resistance. The present invention relates to a lithium soap grease composition.

Lithium soap grease is widely used as a general-purpose IJ grease because it does not have any noticeable drawbacks in general applications. Among these, a particularly useful one is one using lithium hydroxystearate as a thickener, which maintains excellent mechanical stability and water resistance and is widely used under temperature conditions of 120° C. or lower.

However, as the conditions of use become harsher and the temperature at which it is used rises, conventional lithium soap grease softens and oozes out, making it unsatisfactory in terms of heat resistance. For example, it is not uncommon for wheel bearings to reach temperatures of 91,800°C or higher, and conventional lithium soap grease lacks heat resistance and there is a risk of soiling disc brakes due to softening and leakage. Another example is the lubrication of hot air venturator bearings. In this case, the temperature inside the bearing may rise to 150C to 200C, and the dropping point is 200C.
Lithium soap greases below C can no longer be used for the lubrication of this type of bearing.

In order to improve this situation, research has been conducted to improve the heat resistance of lithium soap grease so that it will not flow even at high temperatures of 150 C or higher, and numerous patents have been published. For example stearic acid and 12
- Combinations of higher fatty acids such as hydroxystearic acid with dibasic acids such as azelaic acid and cepatic acid (U.S. Pat. Nos. 2,896,296 and 2,937,993)
No. 3223633, No. 3791973) and combinations of lithium salts of higher fatty acids with esters of boric acid and phosphoric acid and lithium salts (U.S. Patent No. 2872)
No. 417.

No. 3988248, Japanese Patent Publication No. 53-37082) Furthermore, combinations of lithium salts of higher fatty acids with lithium salts and esters of aromatic carboxylic acids have been announced (U.S. Patent Nos. 3929651 and 3758407). .

These are called lithium complex greases and are said to have a dropping point of 250C or higher. However, it has been found that these lithium complex greases have a major drawback in that they leak 200 c even though they have a high perfect score.

The present invention aims to solve these problems by paying particular attention to these points, and as a result of intensive studies by the present inventor, it has been found that the present invention has a high dropping point and little change in consistency at high temperatures. The company has developed a new high-quality, high-dropping-point grease composition with excellent shear stability, water resistance, and oxidation stability.

That is, the present invention binds boric acid or phosphoric acid to the hydroxyl group of hydroxy fatty acid to the base oil of mineral oil or synthetic oil,
This high dropping point lithium soap grease is characterized by containing lithium bonded to the carboxyl group and glycerin ester portion as a thickener. The present inventor utilized the reactivity of hydroxyl groups in fats and oils to react a part of the hydroxyl groups in fats and oils with an inorganic acid such as boric acid or phosphoric acid, and after esterifying the hydroxyl groups in fats and oils, the remaining hydroxyl groups in fats and oils were esterified. They discovered that a lithium soap grease with a high dropping point could be obtained by saponifying the fatty acid and fatty acid groups of the glycerin ester moiety with lithium hydroxide and binding lithium as a thickener. As a method for measuring the amount of hydroxyl groups in fats and oils, a method is known in which acetyl chloride or acetic anhydride is reacted with the hydroxyl groups in fats and oils in the presence of pyridine. When reacting with various acids, it is effective to use a metal oxide such as titanium oxide, viridi, cyan, etc. as a catalyst in order to promote the entire reaction. In order to further improve the heat resistance of the grease of the present invention, it is more effective to use hydroxystearic acid in combination with a linear higher fatty acid such as stearic acid or a branched fatty acid such as itstearic acid.

The base oil component used in the present invention is derived from petroleum and generally includes hydrocarbon oils and synthetic lubricating oils having a lubricating oil viscosity that are solvent refined and hydrocracked or hydrofinished.

Synthetic lubricating oils include hydrocarbon oils such as ethylene and propylene polymerized oils and non-hydrocarbon oils, such as Nisder oils such as di-M acid esters, silicate esters, phosphate esters, neopentyl polyol esters, and polyesters. Polyglycol oils such as alkylene glycol, polyphenyl ether oils, polyolefin oils, silicone oils, and halocarbon oils such as chlorofluorocarbon oils can be used as base oils.

Hydroxy fatty acids as thickener raw materials used in the present invention include 12-hydroxystearic acid and castor wax, which are obtained by hydrogenating castor oil and have one hydroxyl group in the molecule, and oleic acid, which has one double bond. 9,1.0-dihydroxystearic acid, which is obtained by adding a hydroxyl group to a fatty acid and has two hydroxyl groups in its molecule, and tetrahydroxystearic acid, which is obtained by adding a hydroxyl group to a fatty acid with two double bonds; Hexahydroxy acids obtained by adding hydroxy groups to fatty acids having three bonds can be used. 12-Hydroxystearic acid is a saturated fatty acid obtained by hydrogenating ricinol, which is present in castor oil from 80 to 85%, and has one hydroxyl group in the molecule. Dihydroxystearic acid is obtained by subjecting oleic acid to an addition reaction of hydroxyl groups under mild oxidation conditions, and has two hydroxyl groups in the molecule. A hydroxyl group is obtained by adding a hydroxyl group to a double bond in a molecule; an acid with one double bond yields a dihydroxy acid, a tetrahydroxy acid with two bonds, and a tetrahydroxy acid with three bonds. gives hexahydroxy acid.

Boric acid or phosphoric acid is effective as an inorganic acid to be reacted with the hydroxyl group of the hydroxy acid.

Lithium hydroxide is used as the metal for saponifying the reaction product of the hydroxy fatty acid and the inorganic acid.

The present invention will be explained in detail below by specifically showing examples.

Example 1゜Composition of raw materials used Hydrogenated castor oil 11.7% by weight Boric anhydride 0.7 parts by weight Lithium hydroxide
1.61 Mineral oil lubricating oil (SAE20.VI 10
0) 85.0 & antioxidant (aromatic amine)
1.02 50 parts mineral oil lubricant, 11.7 parts castor hydrogenated oil and 0.7 parts
Part of an aqueous solution of boric anhydride is placed in an autoclave reactor and heated with vigorous stirring.

While maintaining the pressure at 5.0 kg/crd, increase the pressure to 1800 to allow both to react sufficiently. Next, the remaining 35 parts of mineral oil lubricating oil was added and heated, and then 10 parts of an aqueous solution of lithium hydroxide was added, heated again, and degassed at 160 C to remove moisture. Thereafter, the temperature was further increased and the maximum heating temperature was maintained at 190C for a while, and then allowed to cool. Add 1.0 part of antioxidant at 100C, mix well, and apply a disper mill.

Example 2 Combination of raw materials used Hydrogenated castor oil 11.8% by weight Boric anhydride 0.2 Lithium monohydroxide
1.6I mineral oil lubricant (SAE20.VIloo)
85.4% by weight antioxidant (aromatic amine)
i, o Add 11.8 parts of hydrogenated castor oil, 0.2 parts of a 20% aqueous solution of boric anhydride, and methanol, and heat and stir in an autoclave reactor until the temperature reaches 1500. Make sure that the pressure does not exceed 5 cm. Next, 85.4 parts of mineral oil lubricating oil was added and the temperature was lowered, and then 1.6 parts of an aqueous solution of lithium hydroxide was added, heated again, and degassed at 160 il:l' to completely remove water and methanol. Then 180C
Heat it up to a temperature, hold it for a while, then release it.

Add 1.0 part of antioxidant to 100 U, mix well, and then apply a disper mill.

Example 3゜Composition of raw materials used Hydrogenated castor oil 12.0% by weight Phosphoric anhydride 0.9 #Lithium hydroxide
1.61 Mineral oil lubricating oil (SAE20.VIloo) 84.5
#Antioxidant (aromatic amine) X, Or The manufacturing method was carried out according to Example 1.

The properties of Examples 1 to 3 above were compared to commercially available lithium.As shown in the above results, the grease according to the present invention has a high dropping point, little change in consistency at high temperatures, and excellent oxidation stability and miscibility stability. This is a new, high-quality lithium soap grease that retains the oil and has a low degree of oil separation. Since the high-spot lithium soap grease according to the present invention has the above-mentioned advantages, it can be used in applications that cannot be satisfied with conventional greases, and is extremely practical and has a wide range of applications.

−724=

Claims (1)

[Claims] It is characterized by containing, as a thickener, a base oil of mineral oil or synthetic oil, in which boric acid or phosphoric acid is bound to the hydroxyl group of a hydroxy fatty acid, and lithium is bound to the carboxyl group and glycerin ester part. High dripping point lithium soap grease.