JPH115988A - Flame-retardant polyester-based lubricating oil composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having a kinematic viscosity in a specified range and improved flame retardancy, by making the composition contain a synthetic polymeric compound in a base oil comprising an unsaturated fatty acid polyol ester in a specified ratio. SOLUTION: The base oil contains an unsaturated fatty acid polyol ester, 0.1-15 mass % at least one synthetic polymeric compound having a weight- average molecular weight of 20,000-1,500,000 and selected from among polymethyacrylates and polyisobutylenes, etc., and optionally 0.8-5 mass % antioxidant such as a phenol/α-naphthylamine dehydration condensate, 0.01-30 mass % rust preventive, 0.01-5 mass % corrosion preventive, etc., to obtain the lubricating oil composition having a kinematic viscosity (at 40 deg.C) of 10-150 mm<2> /s. The unsaturated fatty acid polyol ester has a kinematic viscosity (at 40 deg.C) of 20-100 mm<2> /g and is exemplified by an ester obtained by reacting an 8-32C unsaturated monocarboxylic acid with a 2-10C polyol or a complex ester obtained by reacting an 8-54C unsaturated monocarboxylic acid with a polyol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyol ester-based lubricating oil composition having excellent flame retardancy based on an unsaturated fatty acid polyol ester.

[0002]

2. Description of the Related Art Polyol esters of fatty acids have been widely used as base oils for lubricating oils. Its applications cover a wide range such as gas turbine engine oil, automobile engine oil, hydraulic oil and rolling oil. Since lubricating oils are often used at high temperatures for the purpose, those having a high flash point are often required. Therefore, polyol esters of fatty acids have a higher flash point than mineral oil-based base oils, and are therefore treated as flame-retardant hydraulic oils in hydraulic oils and the like.

[0003]

However, these conventional polyol ester-based hydraulic oils have a low effect on flame retardancy. In particular, the polyol ester base oil uses an unsaturated fatty acid represented by oleic acid. In the case of the synthesized polyol ester, it is considered to be due to a hydrocarbon bond, which has a structure that is easily combustible because it is thermodynamically unstable, and a composition having a further effect of improving flame retardancy is considered. I have been asked. Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and aims to greatly improve the flame retardancy of a polyol ester-based lubricating oil composition using an unsaturated fatty acid polyol ester as a base oil, thereby achieving combustion. An object of the present invention is to provide a polyol ester-based lubricating oil composition which is difficult to perform and contributes to preservation of a working environment.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above problems, and as a result, when a specific amount of a specific synthetic polymer compound is blended with a polyol ester base oil, It has been found that a polyol ester-based lubricating oil composition having extremely excellent flame retardancy can be obtained, and the present invention has been completed based on this finding. That is, the present invention provides a base oil comprising an unsaturated fatty acid polyol ester,
An object of the present invention is to provide a polyol ester-based lubricating oil composition comprising a synthetic polymer compound in a ratio of 0.1 to 15% by mass. Hereinafter, the present invention will be described in detail.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the polyol ester-based lubricating oil composition of the present invention, one or a mixture of two or more unsaturated fatty acid polyol esters is used as a base oil.
The unsaturated fatty acid polyol ester is an ester obtained by reacting an unsaturated monocarboxylic acid with a polyol, or a complex ester obtained by reacting an unsaturated monocarboxylic acid with an unsaturated polycarboxylic acid and a polyol. The details of the manufacturing method are described in JP-A-6-3
No. 3082. The unsaturated monocarboxylic acid has one or more double bonds, preferably 1 to 5 double bonds.
And more preferably 1 to 3, and preferably a linear one. The carbon number of the unsaturated monocarboxylic acid is 8
To 32 are preferred, and particularly preferably 12 to 20.
If the number of carbon atoms is less than 8, high lubricity cannot be obtained and 3
If it exceeds 2, the effect of improving the viscosity index can be seen,
It is not preferable because low-temperature fluidity cannot be obtained.

Specific examples of unsaturated monocarboxylic acids include:
For example, teracrylic acid, undecylenic acid, oleic acid,
Elaidic acid, linoleic acid, linolenic acid, arachidonic acid and the like, and furthermore, a mixture of unsaturated monocarboxylic acids such as palm oil and fat may be used, preferably oleic acid, palm oil and fat, and particularly preferably oleic acid Is an acid. These unsaturated monocarboxylic acids may be used alone or in a combination of two or more.

[0007] The unsaturated polycarboxylic acid has two or more, preferably two to three carboxyl groups. In addition, one or more double bonds, preferably 1 to 5
And more preferably 1 to 3. The carbon number of the unsaturated polycarboxylic acid is preferably from 8 to 54, particularly preferably from 36 to 54. If the carbon number is less than 8,
Lubricity decreases, and if it exceeds 54, low-temperature fluidity decreases, which is not preferable. Specific examples of unsaturated polycarboxylic acids include, for example, adipic acid, 2,2-dimethylsuccinic acid, 2,3-dimethylglutaric acid, suberic acid, azelaic acid, trimethyladipic acid, sebacic acid, isophthalic acid, dimer acid And trimer acid. These unsaturated polycarboxylic acids may be used alone or in a combination of two or more.

The polyol has two or more, preferably three to four, hydroxyl groups. The carbon number of the polyol is preferably 2 to 10, particularly preferably 5 to 5.
~ 6. If the number of carbon atoms is less than 2, the flammability and volatility will decrease, and if it exceeds 10, the low-temperature fluidity will decrease. The polyol is preferably a polyol having no hydrogen bonded to the β-position. This is because when hydrogen is bonded to the β-position, it is thermodynamically unstable and has poor thermal oxidation stability. Further, the polyol is preferably an aliphatic polyol. More preferably, a saturated polyol is preferred.

Preferred examples of the polyol include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2
-Propylene glycol, 1,3-propylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, glycerin, trimethylolmethane, trimethylolethane, trimethylolpropane, trimethylolbutane,
Examples thereof include 2,6-hexanetriol and pentaerythritol, and preferably include neopentyl glycol, trimethylolpropane, and pentaerythritol. These polyols may be used alone or in combination of two or more.

The ester obtained by the reaction of the above compound (ester obtained by reacting an unsaturated monocarboxylic acid and a polyol) has a kinematic viscosity at 40 ° C. of about 20 to 100.
mm ² / s is preferred, and particularly preferably 24 to
75 mm ² / s. If the kinematic viscosity is less than 20 mm ² / s, there is a problem in load resistance, and if it exceeds 100 mm ² / s, the low-temperature fluidity decreases, which is not preferable. The kinematic viscosity of the complex ester at 40 ° C. is 20 to
100 mm ² / s is preferred, and particularly preferred is 24 to
75 mm ² / s. If the kinematic viscosity is less than 20 mm ² / s, the load resistance decreases, and if it exceeds 100 mm ² / s, the low-temperature fluidity decreases, which is not preferable.

The synthetic polymer compound to be added to the polyol ester-based lubricating oil of the present invention is not particularly limited, but any compound may be used as long as it can be dissolved in a base oil composed of a polyol ester. Molecular weight 20,000 ~
1.5 million is preferable, and 100,000 to 3 is particularly preferable.
100,000. If the weight average molecular weight is less than 20,000, flame retardancy cannot be obtained, and if it exceeds 1.5 million, it is not preferable because it is insoluble in base oil.

Suitable specific examples of the synthetic polymer compound include, for example, polymethacrylate, polyisobutylene, ethylene-propylene copolymer, styrene-butadiene random copolymer hydride, styrene-isoprene block copolymer hydride, styrene -Maleic anhydride copolymers. These synthetic polymer compounds may be used alone or in combination of two or more. The compounding ratio of the synthetic polymer compound is 0.1 to 15% by mass based on the total amount of the lubricating oil composition of the present invention.
And preferably 0.3 to 10% by mass. If the synthetic polymer compound is less than 0.1% by mass, the flame retardancy is not sufficient, and if it exceeds 15% by mass, the shear stability of the lubricating oil is affected, which is not preferable.

The polyol ester-based lubricating oil composition of the present invention may further comprise a phenol-α-naphthylamine dehydration condensate or an alkylated phenol-α-alkylated naphthylamine dehydration condensate in addition to the above-mentioned components to further improve flame retardancy Can be obtained. Phenol-α-naphthylamine dehydration condensate or alkylated phenol-α
-The compounding ratio of the alkylated naphthylamine dehydration condensate is
With respect to the total amount of the ester-based lubricating oil composition of the present invention,
It is preferably 0.8 to 5% by mass, particularly preferably 1 to 2% by mass.

The polyol ester-based lubricating oil composition of the present invention may contain, in addition to the above components, appropriate amounts of other additive components, if necessary. Other additives include
For example, components used in ordinary lubricating oil compositions, for example, various additives such as antioxidants, rust inhibitors, corrosion inhibitors, and defoamers can be appropriately added. Examples of the antioxidant include 2,6-di-tert-butyl-p-cresol, 1,1-bis (4-hydroxyphenyl) cyclohexane, and 4,4′-bis- (2,6-diisopropylphenol). , 2,4-di-tert-butyl-p-
Phenolic compounds such as cresol, aromatic amines such as dioctyldiphenylamine, phenothiazine, N, N'-disec-butyl-p-phenylenediamine, and metal salts such as antimonydiamildithiocarbamate and zincdiamildithiophosphate. Is mentioned. As a rust inhibitor, for example, alkenyl succinic acid and its derivatives, esters such as sorbitan monooleate,
Wax oxides, neutral barium sulfonate, sorbitan triol, paraffin or other amines, and the like, as corrosion inhibitors, for example, dialkyl dithiophosphate, benzotriazole and its derivatives, 1,
3,4-thiadiazole polysulfide, 1,3,4-
Examples include thiazolyl-2,5-bisalkyldithiocarbamate, and examples of the antifoaming agent include polydimethylsiloxane.

The amounts of these additives may be appropriately selected, but usually 0.1 to 2% by mass of an antioxidant, 0.01 to 30% by mass of a rust inhibitor, and 0.01 to 30% by mass of a corrosion inhibitor. ~ 5
% By mass, and 10 to 100 ppm of an antifoaming agent.
The polyol ester-based lubricating oil composition of the present invention can be prepared by appropriately mixing and mixing predetermined amounts of the above-mentioned components. The method of mixing each component and the method of adding various additives are not particularly limited, and can be performed by various methods, and the mixing order and the addition order can be performed in various mixing orders and the addition order.

The polyol ester lubricating oil composition of the present invention has a kinematic viscosity at 40 ° C. of about 10 to 150 mm ² /
s is preferred, particularly preferably about 40 to 75 mm ² / s
It is. If the kinematic viscosity is less than 10 mm ² / s, there is a problem in flame retardancy. If the kinematic viscosity exceeds 150 mm ² / s, the fluidity decreases and the pressure loss increases, which is not preferable. The polyol ester-based lubricating oil composition of the present invention is used as a lubricating oil for various machines including hydraulic oils, automobile engine oils, gas turbine engine oils, rolling oils, and the like. It has excellent flame retardancy and lubrication effects as a hydraulic oil used as a pressure medium for hydraulic equipment that requires flame retardancy such as a heating furnace.

[0017]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited by these examples. In the examples, a hydraulic oil was prepared by blending essential components and various additives with a base oil, and a flammability test was performed. The types of base oil, essential components and additives used in the preparation of the hydraulic oils of the respective examples and comparative examples, and the evaluation tests are as follows. (1) The following three types of unsaturated fatty acid polyol esters were used. Trimethylolpropane oleate (40 ° C
Kinematic viscosity at, the kinematic viscosity at 46 mm ² / s) pentaerythritol oleate (40 ° C., a kinematic viscosity at 68mm ² / s) Complex ester (VG68) (40 ℃ is 68mm ² / s) of oleic acid and dimer The acid was reacted with trimethylolpropane to obtain a complex ester. (2) Synthetic high molecular compound The synthetic high molecular compound uses polymethacrylate, polyisobutylene, styrene-butadiene random copolymer hydride, and styrene-maleic anhydride copolymer, and the average molecular weight of each is shown in Table 1. Show. The average molecular weight was measured by the GPC method and calculated in terms of polystyrene.

[0018]

[Table 1]

(3) Phenol-α as an antioxidant
-Naphthylamine dehydration condensate, 2,6-di-tert-
Butyl-p-cresol was used. (4) Benzotriazole was used as a corrosion inhibitor. (5) Alkenyl succinic acid half ester and dicyclohexylamine oleate were used as rust inhibitors. (6) Evaluation method The flame retardancy was evaluated by using a combustion characteristic evaluation test (High Pressure Spray Ignition Test Method, Technical Research Institute of Japan Machinery Promotion Association). The evaluation method uses the propane flame as the ignition source to ignite the sprayed lubricating oil, measures the time from ignition to extinction, and burns the time under the following conditions of equipment and conditions. As the duration, the flame retardancy of the lubricating oil was evaluated. Test conditions (1) Fluid temperature: 65 ± 2 ° C (2) Spray pressure: 70 ± 3 bar (3) Spray nozzle: L ・ report 6.15 predetermined hollow cone (4) Point Flame: propane flame (length of flame) 30-40c
m) (5) Wind speed: 0.3 m / s or less in spray direction (6) Measurement item: Combustion continuation time (s) The combustion continuation time was measured, and the flame retardancy was evaluated in four stages shown in the following table.

[0020]

[Table 2] 0 seconds: Ignition only with ignition flame, removing ignition flame and extinguishing fire

Examples 1 to 14 In Examples 1 to 14, lubricating oil compositions were prepared by mixing at the mixing ratios shown in Tables 3 and 4. The obtained lubricating oil was subjected to a combustion property evaluation test, and the results are shown in the lower part of Tables 3 and 4.

Comparative Examples 1 to 11 In Comparative Examples 1 to 7, lubricating oil compositions were prepared by mixing at the mixing ratios shown in Table 5. In Comparative Examples 8 to 11, Table 6 shows the results of using commercially available lubricating oils. An evaluation test was performed on the obtained lubricating oil, and the results are shown in the lower part of Tables 5-6.

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

[Table 5]

[0026]

[Table 6]

[0027]

According to the present invention, it is possible to provide a hydraulic oil having an excellent effect of improving flame retardancy by blending a specific amount of a synthetic high molecular compound with a base oil comprising an unsaturated fatty acid polyol ester. Can be. Therefore, the polyol ester-based lubricating oil composition of the present invention is extremely useful in practical use.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10N 20:00 20:02 30:02 40:08 (72) Inventor Teruaki Onishi 1134-2 Gongendo, Satte City, Saitama Kosmo Research Institute, Ltd. Research and Development Center

Claims (2)

[Claims] 1. A polyol ester-based lubricating oil composition characterized in that a synthetic polymer compound is contained in a base oil composed of unsaturated fatty acid polyol ester in a ratio of 0.1 to 15% by mass. 2. An unsaturated fatty acid polyol ester comprising:
The polyol ester-based lubricating oil composition according to claim 1, having a kinematic viscosity at 0 ° C of 20 to 100 mm ² / s.