JPH05239487A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To provide a lubricating oil composition for various industries and an automobile, improved particularly in thermal stability and high-temperature oxidation stability and having a prolonged service life. CONSTITUTION:A base material comprising either a copolymer of a 10-16C alpha-olefin with an alpha,beta-unsaturated dicarboxylic acid ester or a lubricating oil containing at least 10wt.% of the copolymer is mixed with 1-15wt.% sulfurized alkaline earth metal salts of hydroxyalkylbenzoic acids and/or alkylphenols.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition for various industries or automobiles, and more particularly to a lubricating oil composition having improved thermal stability and high temperature oxidation stability.

[0002]

2. Description of the Related Art Lubricants that have been conventionally used are
Mineral oil or synthetic oil is used as the base oil.
Usually, various additives are blended according to the purpose. By the way, in recent years, in industrial and automobile lubricating oils, there has been a demand for extension of the oil-refreshing period, and higher thermal stability and high-temperature oxidation stability have been required.

In order to meet this demand, antioxidants, detergents, dispersants and the like are usually compounded. On the other hand, for base oils, it has become important to use those having more excellent oxidative stability, and JP-A-62-240385 discloses a lubricating oil composition using a poly-α-olefin. JP-A-201995 discloses a lubricating oil composition using polyglycol.

[0004]

However, the above-proposed base oil not only has drawbacks such as poor solubility at high temperatures but also high temperature detergency, it is expensive and still required. It does not satisfy the performance. Moreover, it is necessary to improve the oxidative stability of various additives used in combination or to develop an effective blending technique.

In view of the above-mentioned circumstances, the present invention has an object to provide a lubricating oil composition which has excellent thermal stability and high temperature oxidation stability and has an extended re-oiling period. ..

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a copolymer of an α-olefin and an α, β unsaturated dicarboxylic acid ester,
Alternatively, it has been found that a composition obtained by mixing a hydroxyalkylbenzoic acid and / or an alkylphenol alkaline earth metal salt sulfide in a lubricating oil containing the same improves thermal stability and high temperature oxidation stability, and It came to completion.

That is, the gist of the present invention is that (A) a copolymer of an α-olefin having 10 to 16 carbon atoms and an α, β unsaturated dicarboxylic acid ester, or a copolymer thereof.
Lubricating oil containing 0% by weight or more is used as a base material.
(B) Hydroxyalkyl benzoic acid and / or alkylphenol alkaline earth metal salt sulfide (hereinafter,
1 to 15% by weight of "hydroxybenzoate / phenate sulfide" is contained in the lubricating oil composition.

The composition of the present invention will be described in more detail. A copolymer of an α-olefin having 10 to 16 carbon atoms, which is the component (A), and an α, β unsaturated dicarboxylic acid ester, or 10 units of the copolymer. The component (B) is contained in an amount of 1 to 15 with respect to a base material made of a lubricating oil containing at least 20% by weight, preferably at least 20% by weight.
%, Preferably 3 to 10% by weight.

The component (A), which is the base material, has 10 to 1 carbon atoms.
In the case of a copolymer composed of the α-olefin of 6 and an α, β-unsaturated dicarboxylic acid ester and a lubricating oil, if the amount of the copolymer is less than 10% by weight, the heat resistance decreases. The more the copolymer of the α-olefin and the α, β unsaturated dicarboxylic acid ester, the more the heat resistance is improved. Therefore, the copolymer is 100% by weight, that is, as a normal lubricating base oil described below. The base material may be one that does not contain the used mineral oil or synthetic oil. Component (B) is 1% by weight
If it is less than the above range, the heat resistance is lowered, and even if the amount is more than 15% by weight, the effect is not changed, which is economically disadvantageous.

The constituent (A) component has 10 to 10 carbon atoms.
The copolymer of 16 α-olefins with α, β unsaturated dicarboxylic acid ester has a reaction temperature of 140 ° C to 210 ° C in the presence of a peroxide catalyst in an inert gas atmosphere such as nitrogen gas.
It can be obtained by copolymerization at ℃.

Specific examples of the α-olefin having 10 to 16 carbon atoms include 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene and 1-hexadecene.

Examples of the acid of the α, β unsaturated dicarboxylic acid ester include maleic acid, fumaric acid, citraconic acid, mesaconic acid, itaconic acid and the like, and preferably diesters of maleic acid and fumaric acid can be used.

The alcohol component which reacts with these carboxylic acids to form an ester has 3 to 10 carbon atoms.
Thus, a linear or branched monoalcohol is used. Specifically, propanol, butanol, 2-methyl-1
-Propanol, 2-methyl-2-propanol, pentanol, 2-methyl-1-butanol, 3-methyl-
1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1-propanol, hexanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 3-methyl-3-
Pentanol, 2,3-dimethyl-2-butanol,
3,3-dimethyl-2-butanol, heptanol, 3
-Ethyl-3-pentanol, 2,3-dimethyl-3-
Pentanol, 2,3,3-trimethyl-2-butanol, octanol, 2-ethyl-1-hexanol, nonanol, 2,6-dimethyl-4-heptanol, decanol and the like can be mentioned, preferably butanol, hexanol, Octanol can be used.

The peroxide catalyst used when copolymerizing the above-mentioned α-olefin and α, β-unsaturated carboxylic acid ester includes potassium peroxodisulfide, ammonium peroxodisulfide, and t-butylhydrochloride. Peroxide, di-t-butyl peroxide, cumene hydroperoxide, acetyl peroxide, benzoyl peroxide, lauroyl peroxide, azobisisobutyronitrile, azobis-2,
4-Dimethylvaleronitrile, azobiscyclohexanecarbonitrile, t-butyl hydroperoxide, di-t-butyl peroxide and the like can be mentioned.

The lubricating oil containing the above-mentioned copolymer of α-olefin and α, β unsaturated dicarboxylic acid ester is
Normally, if it is used as a lubricating base oil,
Mineral oil, synthetic oil, etc. can all be used.

The component (B), hydroxybenzoate / phenate sulfide, has a gram-equivalent ratio of 0.9 with respect to phenols, dihydric alcohols and phenols.
Reacting a reaction raw material mixture consisting of an oxide or hydroxide of an alkaline earth metal of 9 or less or a mixture thereof (hereinafter, referred to as “alkaline earth metal agent”),
Next, 95% or more of water is distilled off, dihydric alcohol is distilled off to 0.6 mol or less per mol of the alkaline earth metal chemical, and the obtained distillation column bottom product is reacted with carbon dioxide.
The obtained product contained 0.
It can be obtained by reacting 1 to 4.0 mol of elemental sulfur (see JP-A-64-29354).

That is, as described in JP-A-64-29354, in the reaction of the above reaction raw material mixture, a carboxylation reaction partially occurs, and an alkaline earth metal salt of hydroxyalkylbenzoic acid. Sulfide is partially formed, and the final product is a sulfide mixture of an alkaline earth metal salt of hydroxyalkyl benzoic acid and an alkaline earth metal salt of alkylphenol, or the entire product is an alkaline earth metal salt of hydroxyalkyl benzoic acid sulfide. Or all of the alkaline earth metal salt sulfides of alkylphenol are obtained (in the present invention, the sulfides of these three aspects are collectively referred to as
Hydroxybenzoate / phenate sulfide).

More specifically, the phenols used herein have a carbon number of 4 to 36, preferably 8 to.
Mention may be made of mono- or di-substituted phenols having 32 hydrocarbon side chains, for example alkyl, alkenyl, aralkyl groups and the like. Specifically, it is derived from hydrocarbon groups such as butyl, amyl, octyl, nonyl, dodecyl, cetyl, ethylhexyl and triacontyl, or petroleum hydrocarbons such as liquid paraffin, wax and olefin polymers (polyethylene, polypropylene, polybutene, etc.). Phenols having a group that is used alone or in a mixture of two or more. Usually about 130
It is desirable that it can be liquefied at ℃, preferably about 120 ℃.

Specific examples of these phenols include butylphenol, octylphenol, nonylphenol, dodecylphenol, cetylphenol, alkylphenols alkylated with polybutene, dinonylphenol and didodecylphenol. In addition,
Since phenol is a monobasic acid, 1 gram equivalent and 1 mole are synonymous.

As the alkaline earth metal agent, an oxide or hydroxide of an alkaline earth metal is usually used. Specific examples include oxides or hydroxides of calcium, barium, strontium, magnesium and the like. The alkaline earth metal agent is not more than about 0.99 equivalents, preferably about 0.01 to about 1 equivalent of phenols used.
When used in an amount of 0.98 equivalents the desired hydroxybenzoate phenate sulfide is obtained.

Next, as the dihydric alcohol, one having a relatively low boiling point, a low viscosity and a high reactivity, for example, one having 2 to 6 carbon atoms is used. In particular, ethylene glycol, propylene glycol and the like are preferable.

The amount of the dihydric alcohol used is appropriately about 0.15-3.0 mol, preferably about 0.5-1.7 mol, per 1 mol of the alkaline earth metal drug. The dihydric alcohol has an action of assisting the conversion into an oil-soluble substance by the reaction between phenols and an alkaline earth metal drug, and if the amount used is too small, the product conversion rate of the reaction raw material, especially the alkaline earth metal drug (that is, , The reaction rate of the raw materials taken into the product) decreases.

Water can be added to the reaction system in the step of reacting the phenol with the alkaline earth metal chemical, if necessary, and when the water is added, the metal addition reaction proceeds smoothly. As water, not only distilled water but also can water (boiler water), industrial water, water produced by metal addition reaction, and the like can be used. The amount of water to be added is preferably about 0 to 2.0 mol, and more preferably about 0.05 to 1.5 mol per mol of the alkaline earth metal drug.

Sulfur can be used in a wide range of amounts from very small amount to very large amount. Usual usage is
About 0.1 to about 1 mol of the alkaline earth metal agent used
Suitably it is 4.0 moles, preferably about 0.2 to 3.0 moles.

In addition to the above-mentioned components (A) and (B), in the lubricating oil composition of the present invention, known additives that are usually used, such as metal-type detergents, are used depending on the purpose. An ashless type dispersant, a seizure and abrasion inhibitor, a friction modifier, an antioxidant, a corrosion inhibitor, a viscosity index improver, a pour point depressant, an antifoaming agent and the like can be added.

As the metal type detergent, alkaline earth metal sulfonate, alkaline earth metal phenate, alkaline earth metal phosphonate and the like are used. As the ashless type dispersant, alkenyl succinimide, alkenyl succinic acid ester and long chain are used. The amide (aminoamide type) of fatty acid and polyamine, etc., as the anti-seizure friction agent, zinc dialkyldithiophosphate, sulfurized oil and fat, sulfurized olefin, sulfide, phosphoric acid ester, phosphorous acid ester, thiophosphoric acid ester, etc. As the agent, a fatty acid, an organic molybdenum compound or the like, as the antioxidant, zinc dialkyldithiophosphate, an amine / phenolic antioxidant or the like, and as the corrosion inhibitor, benzotriazole, alkenyl succinic acid ester, or the like, As a viscosity index improver,
Examples of the pour point depressant include polymethacrylate and olefin copolymer, and examples of the pour point depressant include polymethacrylate and the like, and examples of the defoaming agent include a silicon compound and an ester-based defoaming agent.

[0027]

In the lubricating oil composition of the present invention, a copolymer of an α-olefin having 10 to 16 carbon atoms and an α, β unsaturated dicarboxylic acid ester having good oxidative stability is used as a base material or a copolymer thereof is used. By using the lubricating oil contained as a base material and blending the component (B) which acts as a detergent, it is possible to further improve the oxidation stability. It is considered that this is due not only to the oxidation stabilizing effect of each of the components (A) and (B) but also to a synergistic effect.

[0028]

EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples, but these are merely examples and the present invention is not limited thereto. In addition, the following reference examples show production examples of hydroxybenzoate / phenate sulfides to be added to the composition of the present invention.

Nine lubricating oil compositions of the present invention shown in Tables 1 and 2 and five comparative lubricating oil compositions shown in Table 3 were prepared.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

The following thermal stability test and oxidation stability test were conducted on the compositions of the present invention and comparative compositions shown in Tables 1 to 3.

As a heat stability test, the following hot tube test was conducted. That is, in the two glass tubes heated to 280 ° C and 300 ° C, which are sending in air,
The above-mentioned lubricating oil of the present invention and comparative lubricating oil are injected at 0.3 ml / h as trial oils. The injected test oil is gradually discharged from the upper outlet while moving up and down in the glass tube. After 16 hours, the glass tube is taken out, washed with n-hexane and then dried to evaluate the concentration of lacquer adhered to the inner wall of the glass tube. The rating was 10 for colorless and transparent with no lacquer attached, and 0 for black and opaque.

The oxidation stability test was carried out under the conditions of 170 ° C. and 24 hours in accordance with the lubricating oil oxidation stability test method for internal combustion engines (JISK2514), and the change in viscosity at 40 ° C. and the change in total acid value were carried out. , And insoluble matter in pentane were measured. The above test results are shown in Tables 4-6.

[0036]

[Table 4]

[0037]

[Table 5]

[0038]

[Table 6]

As is apparent from Tables 4 to 6, the compositions of the present invention are comparative compositions (Comparative Examples 2 to 5) in which the component (A) is not contained in the base oil, and Comparative compositions in which the component (B) is not contained. It can be seen that the thermal stability and the high temperature oxidation stability are excellent as compared with any of the compositions (Comparative Example 1).

Reference Example A nonylphenol 2 was placed in a 5 liter autoclave equipped with a stirrer, a cooling pipe, a nitrogen gas introducing pipe and a thermometer.
379 g (10.8 mol) and 205 g (3.6 mol) of calcium oxide having a purity of 98.4% were inserted and stirred. 345 g (5.4 mol) of ethylene glycol containing 2.8 wt% of water was added to this suspension in a nitrogen stream at 6 kg / cm ^2.
Was added at 155 ° C. under pressure, and the mixture was reacted at 160 ° C. for 3 hours, and then the reaction system was gradually depressurized while adding water, produced water, most of the added ethylene glycol and some of the nonylphenol. When the solvent was distilled off, 2358 g of a mustard-colored liquid distillation residue was obtained. At that time, the temperature of the bottom product at the end was 180 ° C, and the distillate temperature was 160 ° C.
(11 mmHg).

Next, to 2358 g of the above distillation residue, 1
From 20 ° C, 22 mmHg, 275 ml / min (6
Carbon dioxide was blown at a flow rate of (kg / cm ² ) for about 0.6 hours, and the pressure was set to 5.3 kg / cm ² . After that, the temperature was raised to 178 ° C., and then carbon dioxide was blown again 6
When the pressure was increased to kg / cm ² and the state was maintained for 4 hours, 2508 g of a dark gray yellow red liquid reaction product was obtained. The calcium content of this reaction product is 5.76w.
It was t%.

2.00 g of this reaction product was taken in a separating funnel, dissolved in 60 ml of ether, hydrolyzed by adding 15 ml of 1N sulfuric acid (stirring for 60 minutes on a shaker), and after thorough washing with water , The ether layer was separated, then the ether was removed by a rotary evaporator,
1.88 g of a brown liquid was obtained. The acid value of this liquid was 64 mgKOH / g.

On the other hand, 418 g of the carbon dioxide-treated product in the above autoclave was transferred to a 1 liter autoclave, and 23.1 g (0.72 mol) of sulfur was added at 149 ° C. under atmospheric pressure in a CO ₂ stream and the temperature was changed. Was increased to 178 ° C., the pressure was raised to 6 kg / cm ² with CO ₂ , and the mixture was stirred for 4 hours to obtain 436.4 g of an extremely dark yellow-red liquid product. The acid value of this product (measured in the same manner as above, the same applies hereinafter) was 53 mgKOH / g.

392.3 g and 150% of this sulfurization reaction product
165.6 g of neutral oil (paraffinic lubricating oil having a viscosity of 5.38 cSt at 100 ° C.) was placed in a 1-liter three-neck pear-shaped flask, and most of nonylphenol and a small amount of lubricating oil fraction were distilled off. Distillation residue 33
0.9 g was obtained. The final distillate temperature at that time was 19
It was 0 ° C. (2 mmHg).

A very small amount of insoluble matter contained in this distillation residue was removed by filtration to give a viscosity of 131.3 cS.
t (@ 100 ° C.), base number 174 mg KOH / g, calcium amount 6.20 wt%, sulfur amount 3.32 wt%, an extremely dark yellow-red transparent viscous liquid hydroxybenzoate phenate sulfide 328.7 g was obtained. ..

[0046]

As described above, according to the present invention,
It is possible to provide a lubricating oil composition that is much more excellent in thermal stability and high-temperature oxidation stability than conventional lubricating oils. As a result, according to the lubricating oil composition of the present invention, it is possible to extend the re-oiling period in industrial and automotive lubricating oils.

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Claims (1)

[Claims] 1. A base of (A) a copolymer of an α-olefin having 10 to 16 carbon atoms and an α, β unsaturated dicarboxylic acid ester, or a lubricating oil containing 10% by weight or more of the copolymer. 1 to 15 (B) hydroxyalkyl benzoic acid and / or alkylphenol alkaline earth metal salt sulfide.
A lubricating oil composition, characterized in that the lubricating oil composition is contained in a weight percentage.