JPH0892581A - Lubricating composition - Google Patents

Abstract

PURPOSE: To obtain the subject composition imparted with whole characteristics required as the lubricating composition including pressure-resistant lubricity, biodegradability, low-temperature fluidity, hydrolysis resistance, oxidation stability and high viscosity index. CONSTITUTION: This lubricating composition comprises esterified product(s) from castor oil or hydrogenated castor oil and a monofunctional fatty acid with part or the whole thereof being an oxyfatty acid(castor oil fatty acid or hydrogenated castor oil fatty acid) or a condensed fatty acid derived from the monofunctional fatty acid. In this case, this composition essentially contains the esterified product where the constituent fatty acid unit stands at >=3.5mol per mol of the castor oil or hydrogenated castor oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating composition containing a specific esterification reaction product derived from castor oil or hydrogenated castor oil as an essential component. In the present invention, castor oil or hydrogenated castor oil means castor oil and / or hydrogenated castor oil.

[0002]

2. Description of the Related Art Natural triglycerides such as rapeseed oil, palm oil, castor oil, and beef tallow have been used as they are for a long time as a lubricating material. After that, in the era of heyday of petrochemical products, the status of lubricating oil or natural fat and oil as its raw material was replaced by mineral oil and various synthetic esters.

In recent years, however, biodegradable natural fats and oils and esters with a low degree of processing have been reviewed from the viewpoint of preventing environmental pollution. The transition to biodegradable lubricious materials is a matter of time. Particularly in Europe, rapeseed oil and rapeseed oil fatty acid methyl ester have been used. In addition, it has been proposed to improve the lubricating performance by modifying castor oil, which is a natural oil and fat.

That is, in JP-A-50-146556, the main component is obtained by esterifying 1 mol of castor oil or its alkylene oxide adduct and 0.5 to 3 mol of a fatty acid having 4 to 24 carbon atoms. A rolling oil for steel sheets is shown. The fatty acids having 4 to 24 carbon atoms referred to here are lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, maleic acid, adipic acid, azelaic acid, and sebacine. In the examples, as an esterified product of castor oil,
An esterification product of 1 mol of castor oil and 3 mols of stearic acid (Example 1), an esterification product of 1 mol of castor oil and 3 mols of oleic acid (Example 2), 1 mol of castor oil and slightly less than 3 mols of myristic acid Esterified products (Example 3) are listed.

Japanese Unexamined Patent Publication (Kokai) No. 56-14591 discloses a metal rolling oil for high-pressure rolling using a compound obtained by reacting a castor oil-based compound with a polyfunctional compound. Castor oil 1 mol and stearic acid 1
Polyester obtained by further reacting 1 mol of sebacic acid with the reaction product of mol (Example 1), polyester obtained by further reacting 1 mol of azelaic acid with the reaction product of 1 mol of castor oil and 2 mol of stearic acid. (Example 2), a reaction product (Example 3) of 1 mol of castor oil, 2 mol of stearic acid, and 0.5 mol of dimer acid is mentioned.

[0006]

Lubricating materials currently have (1) good pressure-resistant lubricity, (2) biodegradability, (3) low temperature fluidity, and (4) ) It is required to have all the required properties of good hydrolysis resistance, (5) good oxidative stability, and (6) high viscosity index (small temperature dependence of viscosity).

However, among the above-mentioned required characteristics, rapeseed oil has a problem that it is inferior in hydrolysis resistance and inferior in oxidation stability, and it is desired to further improve the pressure-resistant lubricity. Castor oil has problems such as lack of pressure-resistant lubricity, poor hydrolysis resistance, and low viscosity index, resulting in a significant increase in viscosity under winter temperature.If possible, oxidation stability should be improved. is there.

Not only the rapeseed oil and castor oil described above,
Natural oils and fats such as soybean oil, olive oil, palm oil, palm kernel oil, beef tallow, and coconut oil generally have a common weak point that they are poor in hydrolysis resistance. Poor hydrolysis resistance means that acid components are liberated by hydrolysis and metal corrosion is likely to occur. In addition, soybean oil has a problem that its oxidation stability is extremely poor. Olive oil, palm oil, palm kernel oil, beef tallow, and coconut oil have a high pour point of 0 to 6 ° C. for olive oil and 20 ° C. or higher for others, and are difficult to handle when actually used. .

The rolling oil for steel sheets disclosed in Japanese Patent Laid-Open No. 50-146556 has a limit that it is still insufficient in terms of pressure-resistant lubricity and hydrolysis resistance. Does not meet.

The metal rolling oil disclosed in Japanese Unexamined Patent Publication No. 56-14591 also has a problem of insufficient hydrolysis resistance because it reacts with a bifunctional fatty acid.

Under the above circumstances, the present invention has all the characteristics required of a lubricating composition such as pressure-resistant lubricity, biodegradability, low temperature fluidity, hydrolysis resistance, oxidation stability and high viscosity index. It is an object of the present invention to provide a lubricating composition having the dual function.

[0012]

The lubricating composition of the present invention is an ester of castor oil or hydrogenated castor oil and a monovalent fatty acid at least a part of which is an oxy fatty acid or a condensed fatty acid obtained by condensing the fatty acid. A hydrogenated castor oil or hydrogenated castor oil unit 1 in the esterification reaction product
An esterification reaction product in which the constituent fatty acid unit is 3.5 mol or more per mol is an essential component.

The present invention will be described in detail below.

Castor oil is a triglyceride containing less than 3 (more accurately 2.7) ricinoleic acid as a constituent fatty acid in the molecule. Here, ricinoleic acid is a fatty acid having a double bond between the carbon atoms at the 9th to 10th positions among the 18 carbon atoms and having an OH group at the carbon atom at the 12th position. Hydrogenated castor oil is obtained by hydrogenating ricinoleic acid, which is a constituent fatty acid of castor oil, to be converted to 12-hydroxystearic acid.

Examples of monovalent fatty acids include carbons such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, montanic acid, oleic acid, ricinoleic acid and 12-hydroxystearic acid. A fatty acid having a number of 8 or more (particularly, a fatty acid having an iodine value of 110 or less) is used, and may have a branched structure like isostearic acid. Also, a fatty acid derived from a natural product containing these fatty acids or a hydrogenated product thereof may be used.

At least a part (particularly 1 mol or more) of the above fatty acids must be oxy fatty acids such as ricinoleic acid (that is, castor oil fatty acid) and 12-hydroxystearic acid (that is, hydrogenated castor oil fatty acid). Otherwise, the constituent fatty acid unit cannot be 3.5 mol or more per 1 mol of castor oil or hydrogenated castor oil unit.

The above-mentioned fatty acid, at least a part of which is an oxyfatty acid, may be reacted with castor oil or hydrogenated castor oil in the form of condensed fatty acid (estolide) obtained by condensing the fatty acid.

It should be noted that, together with the above-mentioned fatty acids, fatty acids having 7 or less carbon atoms, divalent fatty acids, or fatty acids having a high degree of unsaturation (high iodine value) can be used so long as they do not impair the gist of the present invention. Can also be used together.

The esterification reaction product is composed of castor oil or hydrogenated castor oil, and a monovalent fatty acid at least a part of which is an oxy fatty acid or a condensed fatty acid obtained by condensing the fatty acid. The constituent fatty acid unit per 1 mol of castor oil or hydrogenated castor oil unit in the esterification reaction product is
It should be 3.5 mol or more (particularly 4 mol or more). When the constituent fatty acid unit is less than 3.5 mol, hydrolysis resistance and lubricity are unsatisfactory. The upper limit of the ratio of the constituent fatty acid units is not limited, but the viscosity is too high and it is difficult to handle when the amount is extremely large.

The above esterification reaction product is obtained by subjecting castor oil or hydrogenated castor oil and a fatty acid (or condensed fatty acid) to an esterification reaction under heating. This reaction may be carried out without a catalyst, and general esterification of acid catalysts (paratoluenesulfonic acid, sulfuric acid, hydrochloric acid, phosphoric acid, etc.), titanium catalysts, boron trifluoride, zinc chloride, sodium methylate, etc. It may be carried out in the presence of a catalyst.

The reaction is usually carried out under an inert gas atmosphere. At the time of reaction, it is preferable to add an appropriate amount of a refluxing solvent such as xylene and remove water by-produced from the system by azeotropic distillation. The reaction temperature is 150 to 250 ° C, especially 160 to 23
Often set to 0 ° C. In some cases, the reaction may be performed under reduced pressure. Since it is not preferable that the fatty acid remains as an unreacted product, if unreacted fatty acid remains at the end of the reaction, it is desirable to remove the unreacted fatty acid out of the system by means such as vacuum distillation.

The above esterification reaction product is used alone as a lubricating composition, or is mixed with a conventionally used or proposed lubricating oil such as animal or vegetable oil, esterified oil or mineral oil in an appropriate ratio. Then used.

The lubricating composition of the present invention containing the above esterification reaction product as an essential component is a lubricating agent for synthetic fiber spinning, hydraulic oil, rolling oil, refrigerating machine oil, insulating oil, air compressor oil, food manufacturing machine lubrication. It can be used for various applications requiring lubrication performance such as oil, automobile engine oil, chain saw lubricating oil, 2-cycle engine lubricating oil, and grease.

[0024]

Nowadays, a lubricating composition is strongly required to have biodegradability, but it is not desirable that other properties be impaired in order to secure biodegradability. However, the above esterification reaction product is not only biodegradable but also has properties required for a lubricating composition, that is, pressure resistant lubricity, low temperature fluidity, hydrolysis resistance, oxidation stability, and high viscosity index. Have both.

[0025]

EXAMPLES The present invention will be further described with reference to examples.

<Synthesis of Esterification Reaction Product> Example 1 In a reactor equipped with a stirrer, a thermometer, a nitrogen introducing tube, and a reflux condenser with a test tube, 930 g of castor oil (1 mol) and 600 g of castor oil fatty acid (2 moles) Mol), stearic acid 568
g (2 mol), 110 g of xylene and 1.2 g of paratoluenesulfonic acid as a catalyst were charged, and under a nitrogen stream, 1
The reaction was carried out at 70 to 220 ° C. for 10 hours while removing by-product water under reflux of xylene. After the reaction, the temperature is 17
Xylene was recovered under reduced pressure at 0 ° C. to obtain an esterification reaction product.

Example 2 930 g (1 mol) of castor oil, 900 g (3 mol) of castor oil fatty acid, 600 g (3 mol) of lauric acid, 120 g of xylene and p-toluenesulfonic acid were placed in a reactor.
1.2 g was charged, and the reaction was carried out for 10 hours at 170 to 220 ° C. under a nitrogen stream while removing by-produced water under reflux of xylene. After the reaction, xylene and unreacted lauric acid were recovered under reduced pressure at a temperature of 200 ° C. to obtain an esterification reaction product.

Example 3 930 g (1 mol) of castor oil, 900 g (3 mol) of castor oil fatty acid, 516 g (3 mol) of capric acid, 120 g of xylene and p-toluenesulfonic acid were placed in a reactor.
1.2 g was charged, and the reaction was carried out for 10 hours at 170 to 220 ° C. under a nitrogen stream while removing by-produced water under reflux of xylene. After the reaction, xylene and unreacted capric acid were recovered under reduced pressure at a temperature of 200 ° C. to obtain an esterification reaction product.

Example 4 1800 g (6 mol) of castor oil fatty acid was charged into a reactor and reacted at 170 to 220 ° C. under nitrogen flow for 5 hours while removing by-product water under reflux of xylene. A condensed castor oil fatty acid having an acid value of 60.4 corresponding to a castor oil fatty acid trimer was obtained. Similarly, hydrogenated castor oil fatty acid 900
g (3 mol) was charged into a reactor, and under a nitrogen stream, 170-
The reaction was carried out at 220 ° C. for 5 hours while removing by-product water under reflux of xylene outside the system to obtain a condensed hydrogenated castor oil fatty acid having an acid value of 60.0 corresponding to a hydrogenated castor oil fatty acid trimer.

In the reactor, the condensed castor oil fatty acid obtained above (2 mol as castor oil fatty acid trimer) and hydrogenated condensed castor oil fatty acid (1 mol as hydrogenated castor oil fatty acid trimer).
And 930 g (1 mol) of castor oil and 180 g of xylene were charged.
The reaction was carried out at 0 to 220 ° C. for 10 hours while removing by-product water under reflux of xylene. After the reaction, temperature 170
Xylene was recovered under reduced pressure at 0 ° C. to obtain an esterification reaction product.

Example 5 930 g of hydrogenated castor oil (1 mol), 1050 g of castor oil fatty acid (3.5 mol), and 600 g of lauric acid were placed in a reactor.
(3 mol), 130 g of xylene and 1.2 g of paratoluene sulfonic acid were charged, and under a nitrogen stream, 170 to 220 ° C.
Then, the reaction was carried out for 10 hours while removing by-product water under reflux of xylene. After the reaction, xylene and unreacted lauric acid were recovered under reduced pressure at a temperature of 200 ° C. to obtain an esterification reaction product.

Example 6 930 g (1 mol) of castor oil, 1200 g (4 mol) of hydrogenated castor oil fatty acid, 564 g (2 mol) of oleic acid were placed in a reactor.
Mol), 140 g of xylene and 1.2 g of paratoluenesulfonic acid, and under a nitrogen stream at 170 to 220 ° C.,
While removing the water by-produced under xylene reflux to the outside of the system, 15
Allowed to react for hours. After the reaction, xylene was recovered under reduced pressure at a temperature of 170 ° C. to obtain an esterification reaction product.

Comparative Example 1 A reactor was charged with 930 g (1 mol) of castor oil, 275 g (0.97 mol) of stearic acid, 60 g of xylene and 1.2 g of paratoluene sulfonic acid, and the mixture was heated to 170 to 170 ° C under a nitrogen stream.
The reaction was carried out at 220 ° C. for 5 hours while removing by-product water under reflux of xylene. After the reaction, xylene was recovered under reduced pressure at a temperature of 170 ° C. to obtain an esterification reaction product.

Comparative Example 2 A reactor was charged with 930 g (1 mol) of castor oil, 550 g (1.94 mol) of stearic acid, 75 g of xylene and 1.2 g of paratoluene sulfonic acid, and the mixture was heated to 170 to 170 ° C under a nitrogen stream.
The reaction was carried out at 220 ° C. for 5 hours while removing by-product water under reflux of xylene. After the reaction, xylene was recovered under reduced pressure at a temperature of 170 ° C. to obtain an esterification reaction product.

Comparative Example 3 A reactor was charged with 930 g (1 mol) of castor oil, 825 g (2.9 mol) of stearic acid, 90 g of xylene and 1.2 g of paratoluene sulfonic acid, and the mixture was heated to 170-150 g under a nitrogen stream.
The reaction was carried out at 220 ° C. for 5 hours while removing by-product water under reflux of xylene. After the reaction, xylene was recovered under reduced pressure at a temperature of 170 ° C. to obtain an esterification reaction product.

Comparative Example 4 In a reactor, 930 g (1 mol) of castor oil and 6 lauric acid were added.
00g (3 mol), xylene 80g and paratoluene sulfonic acid 1.2g were charged, and 170 to 22 under nitrogen stream.
The reaction was carried out at 0 ° C. for 5 hours while removing by-product water under reflux of xylene. After the reaction, xylene and unreacted lauric acid were recovered under reduced pressure at a temperature of 200 ° C. to obtain an esterification reaction product.

Comparative Example 5 930 g (1 mol) of castor oil and 5 oleic acid were placed in a reactor.
Charge 50 g (1.95 mol), xylene 75 g and paratoluene sulfonic acid 1.2 g, and in a nitrogen stream, 170 to 2
The reaction was carried out at 20 ° C. for 5 hours while removing by-product water under reflux of xylene. After the reaction, xylene was recovered under reduced pressure at a temperature of 170 ° C. to obtain an esterification reaction product.

Comparative Example 6 In a reactor, 930 g (1 mol) of castor oil, 568 g (2 mol) of stearic acid, 282 g (0.5 mol) of dimer acid.
Then, 8 g of paratoluenesulfonic acid was charged and reacted at 220 to 240 ° C. for 8 hours under a nitrogen stream to obtain an esterification reaction product.

<Evaluation Method and Evaluation Results> Examples 1 to 6
And the esterification reaction products obtained in Comparative Examples 1 to 6, and further, a rapeseed oil, castor oil, mineral oil (150 neutral) or synthetic ester (commercially available hindered ester synthetic ester) as a reference Therefore, various characteristics were measured. The results are shown in Table 1 together with the three-level judgment of ◯ (good), Δ (somewhat insufficient), and × (poor).
Although not described in Table 1, mineral oil is not biodegradable, and in all other cases, it is biodegradable.

[0040]

[Table 1]  Pressure resistance Lubrication at 0 ℃ Hydrolysis resistance Oxidation stability Viscosity index(kg / cm ² ) Liquidity Decomposition rate (%) Example 1 ○ 10.0 ○ L ○ 51.1 ○ 1.5 ○ 132 Example 2 ○ 11.0 ○ L ○ 53.1 ○ 1.5 ○ 137 Example 3 ○ 10.5 ○ L ○ 54.4 ○ 1.5 ○ 132 Example 4 ○ 13.5 ○ L ○ 43.4 ○ 1.2 ○ 128 Example 5 ○ 10.5 ○ L ○ 50.6 ○ 1.2 ○ 133Example 6 ○ 11.0 ○ L ○ 48.5 ○ 1.4 ○ 135 Comparative Example 1 × 6.0 × H △ 68.4 ○ 1.5 ○ 130 Comparative Example 2 △ 8.0 × S △ 63.2 ○ 1.4 ○ 137 Comparative Example 3 △ 8.0 × S △ 60.8 ○ 1.4 ○ 138 Comparative Example 4 △ 7.0 ○ L △ 60.1 ○ 1.4 ○ 136 Comparative example 5 △ 7.5 ○ L △ 65.0 △ 1.8 ○ 136Comparative Example 6 ○ 10.5 ○ L △ 70.7 × 2.4 ○ 132 Rapeseed oil △ 7.5 ○ L × 86.8 × 3.6 ○ 160 Castor oil × 5.5 ○ L × 90.7 △ 1.7 × 86 Mineral oil × 4-5 ○ L ○ 0 ○ 1.4 △ 100-110 Synthetic ester × 4-7 ○ L × 85.5 ○ 1.1-1.5 ○ 115-135

In Table 1, pressure-resistant lubricity, fluidity at 0 ° C., hydrolysis resistance, oxidation stability, and viscosity index were measured or evaluated as follows.

Pressure-resistant lubricity was measured using a Soda four-ball friction tester at 25 ° C. and 200 rpm.

At a fluidity temperature of 0 ° C., a liquid is L, a solid is S, and an intermediate liquid and solid is H.

Viscosity index Based on JIS K 2283. The larger the viscosity index, the smaller the temperature dependence of the viscosity.

0.5 g of a sample was placed in a hydrolysis-resistant 100 cc Erlenmeyer flask, and 1/10 N-
NaOH ethanol / toluene (weight ratio: 80/2
0) 25 ml of the solution was added, and the mixture was heated at the reflux temperature of ethanol for 1 hour, and the decomposition rate (%) with respect to the saponification value was measured. The smaller the decomposition rate, the better the hydrolysis resistance.

The viscosity (cp / 25 ° C.) before and after heating when 10 g of the oxidation stability sample was heated at 170 ° C. for 24 hours was measured, and the ratio of both (viscosity after heating / viscosity before heating) was measured. I asked.

<Discussion> Among the lubricating compositions given as a reference, rapeseed oil is inferior in hydrolysis resistance and oxidation stability, and slightly lacks in pressure-resistant lubricity. Castor oil is inferior in hydrolysis resistance, has a small viscosity index, and thus is inferior in viscosity stability against temperature change, is insufficient in pressure-resistant lubricity, and is also inadequate in oxidation stability. Mineral oil has a basic defect that it does not have biodegradability, and also lacks pressure resistance lubricity and has a low viscosity index. Synthetic esters have poor hydrolysis resistance and lack pressure-resistant lubricity.

The lubricating compositions of Comparative Examples 1 to 5, which consist of esterification reaction products obtained by reacting 1 to 1 mol of castor oil with 1 to 3 mol of fatty acid, are satisfactory in terms of biodegradability, oxidative stability and viscosity index. Although it is possible, the pressure-resistant lubricity is still insufficient,
It can be seen that the hydrolysis resistance is still insufficient and the fluidity at 0 ° C may be insufficient. That is, when viewed comprehensively, some improvement has been made as compared with the lubricating composition given as a reference, but it has not yet reached the present market demand.

2 moles of stearic acid per mole of castor oil
The lubricating composition of Comparative Example 6 comprising the esterification reaction product obtained by reacting 0.5 mol of dimer acid (which is a difunctional fatty acid) has insufficient hydrolysis resistance and inferior oxidative stability.

On the other hand, the lubricating compositions comprising the esterification reaction products of Examples 1 to 6 have biodegradability, excellent pressure-resistant lubricity, and fluidity even at 0 ° C. It has excellent hydrolysis resistance and good oxidative stability.
It can be seen that the viscosity index is high and the viscosity stability with respect to temperature change is good, and therefore all the properties required as a lubricating composition are satisfied.

[0051]

EFFECTS OF THE INVENTION The lubricating composition of the present invention makes use of the goodness of castor oil (or hydrogenated castor oil) and eliminates its drawbacks, and it has pressure-resistant lubricity, biodegradability, low temperature fluidity and It has all the properties required for a lubricating composition such as hydrolyzability, oxidation stability, and high viscosity index.

Claims (2)

[Claims] 1. An esterification reaction product of castor oil or hydrogenated castor oil, and a monovalent fatty acid at least a part of which is an oxyfatty acid, or a condensed fatty acid obtained by condensing the fatty acid, wherein the esterification reaction product 2. A lubricating composition containing as an essential component an esterification reaction product in which the constituent fatty acid unit is 3.5 mol or more per 1 mol of castor oil or hydrogenated castor oil unit. 2. The lubricating composition according to claim 1, wherein the constituent fatty acid unit is 4 mol or more per 1 mol of castor oil or hydrogenated castor oil unit in the esterification reaction product.