JP6434800B2 - Alpha-olefin adsorption inhibiting lubricant composition, adsorption inhibiting method and adsorption inhibitor - Google Patents

Description

  The present invention relates to a lubricant composition, particularly an improvement of industrial lubricating oil such as hydraulic oil and compressor oil.

In lubricating oils such as hydraulic oil and compressor oil, when an additive package containing a rust preventive agent is not used as an additive, good oxidation stability and rust preventive property cannot be obtained. It is difficult to use stably.
Therefore, by adding an additive package containing a rust inhibitor to a lubricant composition used as hydraulic oil, compressor oil, etc., a lubricant composition having desired oxidation stability and rust resistance can be obtained. It has gained.

  Usually, by adding an additive package containing such a rust preventive agent, oxidation stability and rust preventive property can be obtained. However, in certain lubricant compositions, a conventional rust preventive agent as described above is used. It has been found that there are those which cannot obtain sufficient oxidation stability and rust prevention even when an additive package containing them is added.

  It was difficult to determine what caused such a phenomenon that oxidation stability and rust prevention could not be obtained. However, as a result of various researches and explorations, API was added to the base oil of the lubricant composition. It has been found that such phenomena can be seen when using the base oil group III, group IV, polyisobutylene classified into group V, and mixtures thereof.

  Therefore, when various tests and analyzes were conducted to further investigate the cause, it was finally due to the presence of α-olefins having a trace amount of double bonds in the lubricant composition. It has been speculated that the cause is that the α-olefin has an adsorptivity to the metal surface of the object to be lubricated. In addition, it was speculated that α-olefin has a high reactivity and thus has an adverse effect on oxidation stability.

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  As described above, the present invention provides a lubricant composition such as hydraulic oil, compressor oil, etc., which is applied to the metal surface against a small amount of α-olefin having an adverse effect on its oxidation stability and rust prevention. In order to prevent it from acting, it is intended to obtain a lubricant composition excellent in oxidation stability and rust prevention property by inhibiting the adsorptivity of α-olefin.

The present inventors conducted tests to confirm the effect of various substances for the purpose of inhibiting the adsorption action of α-olefin present in a trace amount in the lubricant composition. However, it has been found that anything having an antirust action is not effective.
In addition, since Group III and Group IV base oils have a saturated hydrocarbon content of 90% by mass or more, it is necessary to add a large amount of an additive having a rust preventive effect to obtain a desired effect. It has also been found that it is necessary to select an additive that is effective with a small addition amount, since the solubility of the additive in oil is low and it is disadvantageous from the viewpoint of economics associated with the addition of a large amount.

And when a sarcosine acid derivative, an aspartic acid derivative, and a diethanolamine derivative were used in these, it turned out that the lubricant composition excellent in favorable oxidation stability and rust prevention property is obtained.
That is, the present invention has been completed based on the knowledge that the addition of substances as described above can inhibit the adsorption action of α-olefins mixed in the lubricant composition.

  The present invention relates to a lubricant composition comprising a base oil of any of polyisobutylene classified into Group III, Group IV and Group V by API or a mixture thereof, and containing a small amount of α-olefin. An acid derivative, a diethanolamine derivative or a mixture thereof is added to inhibit adsorption of the α-olefin.

  According to the present invention, by inhibiting the adsorption action of a small amount of α-olefin mixed in the lubricant composition, it is possible to improve the oxidation stability and the rust prevention property in the lubricant composition, thereby providing excellent lubrication. An agent composition can be obtained.

  In the present invention, the base oil of the lubricant composition includes poly α-olefins (PAOs) belonging to Group IV in the classification of base oils by API, highly hydrocracked and refined sulfur content and unsaturated content belonging to Group III. High-viscosity index mineral oil and GTL (Gas Liquid), polyisobutylene belonging to Group V, and mixed oils thereof.

Even in the case of using a package additive containing a general anticorrosive agent in a lubricant composition using, as a base oil, polyisobutylene classified into Group III, Group IV, or Group V, a desired composition can be obtained. There are some which cannot obtain oxidation stability and rust prevention.
The reason why the desired oxidation stability and rust prevention property cannot be obtained as described above is considered to be because a trace amount of α-olefin is mixed in the lubricant composition.

The Group IV PAOs are produced by the polymerization reaction of α-olefins, and α-olefins may be mixed in such a state because some α-olefins having double bonds are in an unreacted state. It is estimated that a trace amount may remain.
And it is thought that sufficient oxidation stability and rust prevention property cannot be obtained by adsorbing such α-olefin on the metal surface. In addition, it is estimated that the α-olefin becomes a nucleus and micelle formation of the rust preventive agent occurs, so that it cannot be adsorbed on the metal surface and does not function as a rust preventive agent.

  In addition, during the production of Group III base oils, hydrocarbon molecules are isomerized by hydrocracking, but in cases where the hydrogen partial pressure is not sufficient or the hydrotreatment is not performed completely, It is estimated that a trace amount of α-olefin is mixed in the lubricant composition using the base oil.

  Polyisobutylene has a long-chain hydrocarbon molecular structure by polymerization of isobutene and is classified as a Group V base oil. In such a thing, it is estimated that the trace amount alpha olefin derived from the isobutene used as a raw material is mixed.

The above-mentioned mixing of a small amount of α-olefin means that 1% by mass or less of α-olefin is contained in the lubricant composition. As an index of unsaturated component, iodine value or bromine value is generally used. Regarding iodine value, JIS K 0070 “acid value, saponification value, ester value, iodine value, hydroxyl value and non-saponification of chemical products” There is a description in "Test method of chemicals".
In the present invention, when the iodine value of the base oil is 1.0 g / 100 g or less, preferably 0.02 g / 100 g or more and 1.0 g / 100 g or less, more preferably 0.09 g / 100 g or more and 1.0 g. / 100g or less is effective. Further, in the present invention, when the bromine number of the base oil is 0.64 g / 100 g or less, preferably 0.01 g / 100 g or more and 0.64 g / 100 g or less, more preferably 0.06 g / 100 g or more. It is effective for 0.64 g / 100 g or less.

  As described above, in the lubricant composition, when sufficient oxidation stability and rust preventive property cannot be obtained even when a package additive containing a general-purpose rust preventive agent is added, the sarcosine acid derivative is added to the lubricant composition. It is effective when added inside.

The sarcosine acid derivative is represented by the following formula 1.

R _{1 in the} above formula 1 is an alkenyl group having 16 to 20 carbon atoms, preferably an alkenyl group having 17 carbon atoms.
When such a sarcosine acid derivative is added, desired lubricant stability and rust prevention can be obtained in the lubricant composition.

  It is not clear why the sarcosine acid derivative added to the lubricant composition inhibits the adsorption action of the α-olefin mixed in the lubricant composition on the metal surface. However, this provides the desired oxidation stability and rust prevention.

  As mentioned above, Group III and Group IV base oils have a high degree of purification as described above. In general, the solubility of additives is low, and the above-mentioned sarcosine acid is used to avoid the uneconomical effects caused by the addition of large amounts. The derivative may be used in an amount of about 0.001 to 3% by mass, preferably about 0.005 to 2% by mass, based on the total amount of the lubricant composition.

As an inhibitor of the α-olefin adsorption described above, there is an aspartic acid derivative. Some of the aspartic acid derivatives are shown in the following formula 2.

In the general formula 2, R ₂ and R ₃ are each hydrogen or the same or different alkyl group, alkenyl group, or hydroxyalkyl group having 3 to 6 carbon atoms, preferably each of 2-methylpropyl group and tertiary Butyl group is good. R ₄ is an alkyl group or alkenyl group having 1 to 30 carbon atoms, an alkyl group having an ether bond, or a hydroxyalkyl group. For example, octadecyl group, alkoxypropyl group, 3- (C6-C18) hydrocarbonoxy (C3-C6) alkyl group, more preferably cyclohexyloxypropyl group, 3-octyloxypropyl group, 3-isooctyloxypropyl group 3-decyloxypropyl group, 3-isodecyloxypropyl group, and 3- (C12-C16) alkoxypropyl group are preferable. R ₅ is a saturated or unsaturated carboxylic acid group having 1 to 30 carbon atoms, or an alkyl group, alkenyl group or hydroxyalkyl group having 1 to 30 carbon atoms. For example, a propionic acid group or a propionyl acid group is preferable.
The aspartic acid derivative may be used in an amount of about 0.005 to 3% by mass, preferably about 0.01 to 3% by mass, based on the total amount of the lubricant composition.

Moreover, there exists a diethanolamine derivative as what inhibits adsorption | suction of the said alpha olefin. This diethanolamine derivative is represented by the following formula 3.

R _{6 in the} above formula 3 is an alkyl group having 16 to 20 carbon atoms, and preferably an alkyl group having 18 carbon atoms.
This diethanolamine derivative may be used in an amount of about 0.001 to 3% by mass, preferably about 0.005 to 2% by mass, based on the total amount of the lubricant composition, like the sarcosine acid derivative.

Hereinafter, the α-olefin adsorption inhibitor of the present invention and the lubricant composition using the same will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto. .
The following were prepared in order to produce Examples and Comparative Examples.

(Base oil)
PAO8: The main component is a poly α olefin in which 3 to 4 α olefins having 10 carbon atoms are polymerized. The iodine value of PAO8 is below the detection limit, and α-olefin is not substantially mixed.
(General-purpose package additive containing rust inhibitor)
Industrial additive package (IRGALUBE 2030A, manufactured by BASF): This R & O type industrial additive package includes N-1-naphthylaniline, N, N-bis (2-ethylhexyl)-(4 or 5)- Methyl-1H-benzotriazole-1-methylamine, (4-nonylphenoxy) acetic acid, alkylated diphenylamine, sterically hindered hindered phenol, acyl sarcosine acid.

(Α-olefin for addition)
As the α olefin in Examples and Comparative Examples, a reagent manufactured by Wako Pure Chemicals, 1-octadecene was used. Since the molecular weight of this compound is 252, the calculated iodine value of this compound alone is 101 g / 100 g, and the bromine value is 63.5 g / 100 g. In the examples and comparative examples, the iodine value derived from the α-olefin of the composition containing 1% by mass of 1-octadecene is 1.0 g / 100 g, and the bromine value is 0.64 g / 100 g. It can be said.

(Additive)
1. Sarcosine acid derivative: oleyl sarcosine acid represented by the above formula 1, wherein R ₁ is a linear alkenyl group having 17 carbon atoms.
2. Aspartic acid derivative: as shown in Formula 2 above, N-1-oxo-3-carbonyloxypropyl-N-3-octyloxypropyl-aspartic acid diisobutyl ester, N-1-oxo-3-carbonyloxypropyl-N -3-decyloxypropyl-aspartic acid diisobutyl ester, N-1-oxo-3-carbonyloxypropyl-N-3-dodecyloxypropyl-aspartic acid diisobutyl ester, N-1-oxo-3-carbonyloxypropyl-N Mixture of -3-tetradecyloxypropyl-aspartic acid diisobutyl ester (acid value according to JIS K2501 method: 100 mgKOH / g)
3. Diethanolamine derivatives: those represented by the above formula 3, _{R 6} is diethanolamine a straight chain alkyl group having 18 carbon atoms (tertiary amine compound) N- alkenyl diethanolamine (main component N- oleyl diethanolamine) (JIS K2501 Base number by the method: 160 mgKOH / g)

4). Succinic acid derivative: tetraisopropenyl succinic acid, 1,2-propanediol half ester (acid value according to JIS K2501 method: 160 mgKOH / g)
5). 5. Epoxidized ester: epoxidized rapeseed fatty acid 2-ethylhexyl ester Calcium salicylate: Ca content is 8% by mass, base number according to JIS K2501 method is 230 mgKOH / g
7). Calcium sulfonate: Ca content is 2.1% by mass, base number according to JIS K2501 method is 0.2 mgKOH / g
8). Alkyl ether carboxylic acid: An acid value according to JIS K2501 method is 120 mgKOH / g.

Example 1
A lubricant composition comprising 98.4% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.1% by mass of a sarcosine acid derivative.
(Example 2)
A lubricant composition comprising 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust preventive agent, 1.0% by mass of an α-olefin, and 0.5% by mass of a sarcosine acid derivative.
Example 3
A lubricant composition comprising 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.5% by mass of an aspartic acid derivative.
(Example 4)
A lubricant composition comprising 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of an α-olefin, and 0.5% by mass of a diethanolamine derivative.

(Comparative Example 1)
It consists only of a base oil whose PAO8 is 100% by mass.
(Comparative Example 2)
A lubricant composition comprising 99.5% by mass of PAO8 and 0.5% by mass of a general-purpose package additive containing a rust inhibitor.
(Comparative Example 3)
A lubricant composition containing 98.5% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, and 1.0% by mass of α-olefin.

(Comparative Example 4)
A lubricant composition comprising 98.4% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.1% by mass of a succinic acid derivative.
(Comparative Example 5)
A lubricant composition comprising 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.5% by mass of a succinic acid derivative.

(Comparative Example 6)
A lubricant composition comprising 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.5% by mass of an epoxidized ester.
(Comparative Example 7)
A lubricant composition comprising 98.4% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust preventive agent, 1.0% by mass of α-olefin, and 0.1% by mass of calcium salicylate.
(Comparative Example 8)
A lubricant composition containing 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.5% by mass of calcium salicylate.

(Comparative Example 9)
Lubricant composition containing 98.4% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.1% by mass of calcium sulfonate. .
(Comparative Example 10)
Lubricant composition containing 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust inhibitor, 1.0% by mass of α-olefin, and 0.5% by mass of calcium sulfonate. .
(Comparative Example 11)
Lubricant composition containing 98.0% by mass of PAO8, 0.5% by mass of a general-purpose package additive containing a rust preventive agent, 1.0% by mass of α-olefin, and 0.5% by mass of alkyl ether carboxylic acid .

(test)
Rust prevention performance test: In accordance with JIS K2510, 300 ml of test oil is collected in a container installed in a thermostatic bath, stirred at 1000 rpm, and when it reaches 60 ° C, an iron test piece is placed in the test oil. Further, 30 ml of artificial seawater was added and stirring was continued for 24 hours while maintaining the temperature at 60 ° C., and then the test piece was taken out and visually evaluated for the presence or absence of rust.
The test was evaluated according to the following criteria.
No generation of rust ......... None (Pass: ○)
Minor rusting is observed .... Minor (failed: x)
Moderate rusting is observed. Moderate (Failure: x)
Severe rusting is seen ........ Severe (failed: x)

  Tables 1 and 2 show the compositions of the above Examples and Comparative Examples and the results of the rust prevention performance test.

(Discussion)
The thing which consists only of the base oil of PAO8 shown in the comparative example 1 has produced the heavy rust.
In Comparative Example 2, 0.5% by mass of a general-purpose package additive containing a rust preventive agent is added to Comparative Example 1, thereby preventing the occurrence of rust.
In Comparative Example 3, 1.0% by mass of α-olefin is added to that of Comparative Example 2, and when α-olefin is mixed in the lubricant composition, a general-purpose package additive containing a rust preventive is included. Even if it is contained, it can be seen that rust (medium) has occurred.

In Example 1, 0.1% by mass of a sarcosine acid derivative was added to the mixture of α-olefins of Comparative Example 3 described above, and in these cases, generation of rust was not observed. In Example 2, 0.5% by mass of a sarcosine acid derivative was also added, and even in such a case, generation of rust was not observed.
In Example 3, 0.5% by mass of an aspartic acid derivative was added to the mixture of α-olefins of Comparative Example 3, and no rust was observed even in such a case.
In Example 4, 0.5% by mass of a diethanolamine derivative was added to the same mixture of α-olefins of Comparative Example 3 described above, and the occurrence of rust was not observed even in such a case.
In this way, even if α-olefin is mixed in the lubricant composition, the addition of a small amount of sarcosine acid derivative, aspartic acid derivative, diethanolamine derivative, etc. inhibits the α-olefin adsorption action and prevents rust. It is thought that it is demonstrated.

In Comparative Example 4, 0.1% by mass of a succinic acid derivative was added to the mixture of α-olefins of Comparative Example 3 described above, and in such cases, generation of rust (medium) was observed. In Comparative Example 5, 0.5% by mass of a succinic acid derivative was also added. In such a case, rust (severe) was observed.
In Comparative Example 6, 0.5% by mass of an epoxidized ester was added to the mixture of the α-olefin of Comparative Example 3 above, and in such a case, generation of rust (severe) was observed.

In Comparative Example 7, 0.1% by mass of calcium salicylate was added to the mixture of α-olefins of Comparative Example 3 described above, and in such cases, generation of rust (severe) was observed. In Comparative Example 8, 0.5 mass% of calcium salicylate was also added, and in such a case, generation of rust (medium) was observed.
In Comparative Example 9, 0.1% by mass of calcium sulfonate is added to the mixture of α-olefins of Comparative Example 3 above, and in such a case, generation of rust (severe) is observed. Further, even in the case of Comparative Example 10 in which 0.5% by mass of calcium sulfonate is added, rust (severeness) is generated.
The thing of the comparative example 11 adds 0.5 mass% of alkyl ether carboxylic acid to what mixed the alpha olefin of the said comparative example 3, and generation | occurrence | production of rust (severity) is seen also in such a thing.

  As described above, succinic acid derivatives, epoxidized esters, calcium salicylates, calcium sulfonates, alkyl ether carboxylic acids, etc., which are generally considered to have an anti-rust action, are used to obtain such an action. It can be seen that the deterioration of rust prevention due to the presence of olefins cannot be prevented by the addition amount which is usually regarded as an appropriate amount.

Claims (6)

Lubricant containing 1% by mass or less of α-olefin based on the base oil of any one of the polyisobutylenes classified into Group III, Group IV and Group V in API base oil classification or a mixture thereof. A lubricant composition, wherein a sarcosine acid derivative, an aspartic acid derivative, a diethanolamine derivative or a mixture thereof as described below is added so as to inhibit the adsorption of the α-olefin on the metal surface.
The sarcosine acid derivative is shown in the following formula 1,
[Chemical formula 1]

(R _{1 in the} above formula 1 is an alkenyl group having 16 to 20 carbon atoms.)
The aspartic acid derivative is represented by the following formula 2,
[Chemical formula 2]

(In the above formula 2, R ₂ and R ₃ are each hydrogen or the same or different alkyl group, alkenyl group, or hydroxyalkyl group having 3 to 6 carbon atoms, and R ₄ is an alkyl group having 1 to 30 carbon atoms or An alkenyl group, an alkyl group having an ether bond, or a hydroxyalkyl group, and R ₅ is a saturated or unsaturated carboxylic acid group having 1 to 30 carbon atoms, or an alkyl group, alkenyl group, or hydroxyalkyl group having 1 to 30 carbon atoms. .)
The diethanolamine derivative is represented by the following formula 3.
[Chemical formula 3]

(R _{6 in} Formula 3 is an alkyl group having 16 to 20 carbon atoms.)   In the case of the sarcosine acid derivative or diethanolamine derivative, 0.001 to 3% by mass is used with respect to the total amount of the composition, and in the case of the aspartic acid derivative, 0.005 to 3% by mass is used with respect to the total amount of the composition. The lubricant composition according to claim 1. Lubricant containing 1% by mass or less of α-olefin based on the base oil of any one of the polyisobutylenes classified into Group III, Group IV and Group V in API base oil classification or a mixture thereof. The method for inhibiting adsorption of the α-olefin to the metal surface, wherein the sarcosine acid derivative, aspartic acid derivative, diethanolamine derivative or mixture thereof according to claim 1 is added to the composition.   The addition amount of the sarcosine acid derivative or diethanolamine derivative is 0.001 to 3% by mass with respect to the total amount of the composition, and the addition amount of the aspartic acid derivative is 0.005 to 3% by mass with respect to the total amount of the composition. Item 4. The method for inhibiting adsorption of α-olefin according to Item 3. Any one of the sarcosine acid derivative, aspartic acid derivative or diethanolamine derivative according to claim 1, or a mixture thereof, and any of polyisobutylene classified into group III, group IV, group V in the base oil classification of API Alternatively, an α-olefin adsorption inhibitor that inhibits the adsorption of the α-olefin on the metal surface in a lubricant composition in which 1% by mass or less of the α-olefin is mixed based on the total amount of the composition using the mixture as a base oil.   The amount of the sarcosine acid derivative or diethanolamine derivative used is 0.001 to 3% by mass based on the total amount of the composition, and the amount of the aspartic acid derivative used is 0.005 to 3% by mass based on the total amount of the composition. Item 6. The α-olefin adsorption inhibitor according to Item 5.