JPH1053780A - Manufacture of lubricating oil base oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of biodegradable lubricating oil base oil having a good low temp fluidity, a low cloud point, and, moreover, good oxidation stability and lubricity. SOLUTION: This base oil is manufactured by an ester exchange reaction of a mixture of 5-35wt.% fat contg. not less than 60wt.% monoene fatty acid having not less than 16 carbons and not more than 12wt.% diene fatty acid in the component fatty acid, 30-60wt.% fat contg. not less than 20wt.% trans acid in the component fatty acid, and 15-45wt.% fat or middle chain fatty acid contg. not less than 80wt.% middle chain saturated fatty acid, or its lower alcohol ester in the component fatty acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricating oil which can be suitably used as an engine oil such as a lubricating oil for rolling, two-stroke and four-stroke, a cutting oil, etc. The present invention relates to a lubricating base oil having both properties and biodegradability.

[0002]

2. Description of the Related Art Lubricating oil requires (1)
(2) good fluidity at low temperatures; (3) high viscosity index; (4) good lubricity such as load-bearing capacity and abrasion resistance. Mineral oils are generally used as lubricating oils, but in recent years high oils with high biodegradability have been required from the viewpoint of environmental protection, mainly in Europe, and mineral oils with low biodegradability Development of alternative base oils is desired.

[0003] Vegetable oils (CEC-
Biodegradation rate by L33-A-93 method of 90 to 100%) and polyol esters (55 to 100% of the same). Vegetable oils and fats have the disadvantage of being inferior in oxidative stability, but have the advantages of high viscosity index, excellent lubricity, extreme pressure properties, low volatility, and good compatibility with additives. I have. Therefore,
In recent years, improvement studies have been made to use vegetable oils and fats as lubricating base oils. For example, there is a liquid oil such as rapeseed oil which is improved in cold resistance, that is, low-temperature fluidity by adding three kinds of polyglycerin fatty acid ester, sucrose fatty acid ester and lecithin (Japanese Patent Laid-Open No. 5-209187). Poor oxidation stability due to use of fat.

It has also been disclosed that a medium-chain saturated fatty acid is introduced into a liquid fat such as rapeseed oil by transesterification to improve low-temperature fluidity (Japanese Patent Application Laid-Open Nos. 6-14710 and 7-179882). Oxidative stability is poor due to the use of oils and fats having a high unsaturated fatty acid content (such as Rancimat stability 4 to 4 in JP-A-7-179882).
About 5 hours). On the other hand, there is an example in which a medium-chain saturated fatty acid is introduced into fats and oils having a low unsaturated fatty acid content, such as hydrogenated coconut oil and palm kernel oil (JP-A-4-31479).
0) Although the oxidative stability is improved, the solid point is high and the cloud point is not satisfactory because of the use of solid fat (often 0 ° C. or higher). To lower the cloud point, a large amount of expensive MCT is required. I need.

[0005] As described above, palm oil, beef tallow, hardened oil and the like which are solid at normal temperature as raw materials have relatively good oxidative stability, but have low melting point and therefore low-temperature fluidity. On the other hand, when oils and fats containing a large amount of highly unsaturated fatty acids such as linseed oil and fish oil, or oils and oils containing a large amount of linoleic acid such as rapeseed oil and soybean oil are used alone as lubricating oils, they have relatively good low-temperature fluidity but oxidative stability. Gets worse. Medium-chain saturated fatty acid triglycerides are known as fats and oils that have both oxidative stability and low-temperature fluidity. However, when used alone, the alkyl group has a short chain compared to common vegetable fats (palm oil, rapeseed oil, etc.), and thus has lubricity. Is inferior. That is, at present, a lubricating oil based on vegetable oil having low-temperature fluidity and oxidative stability has not yet been sufficiently developed.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to develop a biodegradable lubricating base oil which has good fluidity at low temperatures, a low cloud point, good oxidation stability and good lubricity.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, a certain trans acid was present in fats and oils containing a high content of oleic acid. It has been found that oils and fats in which a medium-chain saturated fatty acid having 6 to 12 carbon atoms is coordinated have good low-temperature fluidity, low cloud point, good lubricity, and good oxidative stability. It was just.

[0008] That is, the present invention provides 5-35% by weight of fats and oils wherein the monoene fatty acid having 16 or more carbon atoms is 60% by weight or more and the diene fatty acid is 12% by weight or less in the constituent fatty acids.
30-60% by weight of fats and oils containing 20% by weight or more of trans acid in the constituent fatty acids, and 15-45% by weight of fats or oils containing 80% by weight or more of medium-chain saturated fatty acids in the constituent fatty acids or medium-chain fatty acids or lower alcohol esters thereof. % Of a lubricating base oil which is based on mixing and transesterification.

Among the constituent fatty acids, examples of fats and oils in which the monoene fatty acid having 16 or more carbon atoms is 60% by weight or more and the diene fatty acid is 12% by weight or less include high oleic sunflower oil, hardened soybean fractionated oil, and hardened rice bran oil. High oleic sunflower oil is particularly preferred. If the fat or oil is less than 5%, the low-temperature fluidity becomes poor, and if it exceeds 35% by weight, the oxidation stability becomes poor. On the other hand, when the diene fatty acid exceeds 12% by weight, the oxidative stability deteriorates. Therefore, fats and oils having a high content of diene fatty acids, such as rapeseed oil and safflower oil, are excluded.

As a fat or oil having a trans acid content of 20% by weight or more in the constituent fatty acids, a hardened palm fractionated oil, a hardened soybean fractionated oil,
Hardened rice bran fractionated oil can be mentioned. When the trans-acid content in the constituent fatty acids is less than 30% by weight of the fat or oil having a trans acid content of 20% by weight or more, the oxidative stability is deteriorated.

In the present invention, the medium-chain saturated fatty acid refers to a saturated fatty acid having 6 to 12 carbon atoms. The medium-chain fatty acid preferably has 8 to 10 carbon atoms. Commercially available MCT can be used as the fat or oil containing 80% by weight or more of the medium-chain saturated fatty acid in the constituent fatty acids. 80 medium-chain saturated fatty acids
If the amount of fats and oils contained is less than 15% by weight, it is difficult to obtain low-temperature fluidity, and if it exceeds 45% by weight, lubricity is reduced.

The above fats and oils are mixed and transesterification is carried out. The composition of the mixed oil is generally about 40-5 monoene fatty acids.
It contains 8% by weight, 10 to 20% by weight of trans acid, and 20 to 40% by weight of medium-chain saturated fatty acid. It has a low-temperature pour point and a low cloud point that could not be obtained by simply mixing the fats and oils to be subjected to the reaction by the transesterification reaction. This is because mixed acid triglycerides in which medium-chain saturated fatty acids are introduced into triglycerides are generated. Therefore, the medium-chain saturated fatty acid can be introduced in the form of a triglyceride, a lower alcohol ester of a medium-chain saturated fatty acid, or a free medium-chain fatty acid.

The transesterification is preferably carried out using a lipase having specificity at positions 1 and 3 of glyceride as a catalyst. In the case of random transesterification, the cloud point tends to increase, and a step of separating and removing the high melting point component after the reaction may be required.

A lipase having specificity at positions 1 and 3 of glyceride is Rhizopus delem.
ar), those derived from microorganisms such as the genus Mucor miehei, Alcaligenes, those derived from plants such as soybean, rice bran, and castor seeds, and animal pancreas lipase. . In addition to the lipase itself, an immobilized lipase obtained by a conventional method such as an adsorption method, an ion or covalent bonding method, an entrapment method, or a microorganism such as mold, yeast, or bacteria capable of producing the lipase may be used. .

The synthesized fats and oils can be directly used as a base oil in lubricating oils and the like. However, depending on the raw material oil, purification treatment such as deoxidation, decolorization and deodorization may be carried out.
Additives such as extreme pressure agents, pour point depressants, antioxidants, defoamers, metal detergents, antiwear agents, etc. can be added. Can also be used.

[0016]

【Example】

(Example 1) Hardened palm fractionated oil 54 parts by weight High oleic sunflower oil 6 parts by weight MCT 40 parts by weight The above blended oil was mixed with 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification. As the hardened palm fractionated oil, the low melting point side of the oil obtained by hardening and separating palm olein was used (33% by weight of trans acid, 64% by weight of monoene fatty acid having 16 or more carbon atoms, 4.3% by weight of diene fatty acid having 16 or more carbon atoms). %). High oleic sunflower oil with 1 carbon
The monoene fatty acid content of 6 or more is 81% by weight, and the number of carbon atoms is 1
8.8% by weight of 6 or more diene fatty acids. The composition of MCT is
C8 = 65% and C10 = 35% were used. (Example 2) Hardened palm fractionated oil 50% by weight High oleic sunflower oil 30% by weight MCT 20% by weight The above blended oil was mixed with 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification. (Example 3) Hardened soybean fractionated oil 40% by weight High oleic sunflower oil 20% by weight MCT 40% by weight The above blended oil was mixed with 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification. The hardened soybean fractionated oil is 35% by weight of trans acid, 77% by weight of monoene fatty acid having 16 or more carbon atoms, and 7.5 diene fatty acid having 16 or more carbon atoms.
% By weight.

[0017]

[Comparative example]

(Comparative Example 1) The compounded oil of Example 1 (no transesterification). (Comparative Example 2) The compounded oil of Example 2 (no transesterification). (Comparative Example 3) The compounded oil of Example 3 (no transesterification). (Comparative Example 4) Hardened palm fractionated oil 67.5% by weight High oleic sunflower oil 7.5% by weight MCT 25% by weight The above blended oil was subjected to 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification. (Comparative Example 5) Hardened palm fractionated oil 20.0% by weight High oleic sunflower oil 60.0% by weight MCT 20.0% by weight The above blended oil was treated with 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification. (Comparative Example 6) Hardened palm fractionated oil 40.0 wt% Palm fractionated oil 30.0 wt% MCT 30.0 wt% The above blended oil was treated with a 1,3-specific lipase (Rhizopus niveus)
Was used for transesterification.

Table 1 shows the compositions of the fats and oils obtained in Examples and Comparative Examples.

[0019]

[Table 1]

In order to evaluate the fats and oils of the present invention, the following measurements were performed. (1) Pour point and cloud point: Performed according to JIS K2269 with an automatic pour point and cloud point measuring device (manufactured by Tanaka Scientific Instruments). (2) Oxidation stability (RBOT oxidation stability): This was performed in accordance with JIS K2514 using a rotating cylinder type oxidation stability tester (manufactured by Rigo Co., Ltd.). Rancimat stability: According to a measuring machine manufactured by Metrohm Switzerland. (3) Viscosity index: ASTM D2270-6
Performed according to 4.

[0021]

[Table 2] Pour point Cloud point Rancimat RBOT Ammonium oxide Viscosity index (° C) (° C) Stability (hr) Qualitative (min) ------------------------------------- −−−−−−−−−−−−− Example 1 −5.0 −3.1 45.3 63 148 Example 2 −6.0 −3.2 31.4 34 150 Example 3 −2 2.0 -4.0 37.0 57 155 Comparative Example 1 -1.0 22.9 49.6 85 154 Comparative Example 2 -1.0 15.7 35.3 60 152 Comparative Example 3 2.0 12.1 40.3 71 156 Comparative Example 4 -1.0 10.5 36.2 38 148 Comparative Example 5-14.0 -4.0 10.3 16 152 Comparative Example 6 5.0 15.1 22.5 21 152 Rapeseed oil -18.0 -12.3 3.2 11 148 High oleic -9.0 40.0 9.0 15 152 Sunflower oil --------------------------------------------- ---------------

It can be seen from the examples that the pour point and the cloud point are low and the oxidation stability is high and satisfactory. The oxidative stability is much higher than rapeseed oil or high oleic sunflower oil. In Comparative Examples 1 to 3, the pour point and the cloud point were high because the transesterification was not performed. In Comparative Example 4, as a result of an increase in trans acid, the stability was good, but the pour point and the cloud point were high. In Comparative Example 5, the stability was poor as a result of a decrease in the trans acid and the amount of the monoene fatty acid increased, and in Comparative Example 6, the pour point and the cloud point were increased as a result of the decrease in the monoene fatty acid.

[0023]

[Effect] By introducing a medium-chain saturated fatty acid having 6 to 12 carbon atoms to the 1,3-position of glyceride into a vegetable oil containing a large amount of monoene fatty acid and a vegetable oil having a trans acid content of 20% or more in the constituent fatty acids, A lubricating oil / fat having good stability, good low-temperature fluidity, and a low cloud point could be developed.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location C10N 30:02 30:10 40:20 40:25 70:00

Claims (2)

[Claims] (1) 5-35% by weight of fats and oils comprising 60% by weight or more of monoene fatty acids having 16 or more carbon atoms and 12% by weight or less of diene fatty acids in the constituent fatty acids, and 20% by weight or more of trans acids in the constituent fatty acids. 30-60% by weight of fat
And a fat or oil containing at least 80% by weight of a medium-chain saturated fatty acid or 15 to 45% by weight of a medium-chain fatty acid or a lower alcohol ester thereof in the constituent fatty acids, and subjecting the mixture to a transesterification reaction. Manufacturing method. 2. The process for producing a lubricating base oil according to claim 1, wherein the transesterification reaction is carried out using a lipase having specificity at the 1- and 3-positions of glyceride.