JP2009209261A - Self-extinguishing gear oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flame retarding and self-extinguishing gear oil composition. <P>SOLUTION: This gear oil composition contains (A) 20-70 mass% of phosphorous compound having 1-1,000 mm<SP>2</SP>/s of kinematic viscosity at 40°C, with respect to total base oil amount, and (B) 30-80 mass% of one kind or more selected from the group comprising polyol esters and complex esters having 100-30,000 mm<SP>2</SP>/s of kinematic viscosity at 40°C, and having 200°C or more of flash point, with respect to the total base oil amount, as a base oil, and (C) 0.5-5.0 mass% of tetrazole with respect to total gear oil composition amount, and (D) 0.1-10 mass% of extreme pressure agent containing sulfur, with respect to the total gear oil composition amount, and has 50-1,000 mm<SP>2</SP>/s of kinematic viscosity at 40°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gear oil composition excellent in flame retardancy and self-extinguishing properties.

In recent years, with the development of mechanical technology, equipment has been operated under high speed, high temperature and high load conditions. It is desired that the lubricating oil used in such places is more flame retardant and does not continue to burn even when ignited, that is, has excellent self-extinguishing properties. For example, water-containing systems, fatty acid esters, phosphate esters, and the like are known as flame retardant hydraulic fluids (see, for example, Patent Documents 1 to 3).
On the other hand, improvement in flame retardancy has also been studied for gear oil (see, for example, Patent Document 4).

JP-A-2-214795 JP-A-3-21697 JP-A-11-269480 JP-A-6-264087

However, since the gear oil is required to have excellent lubricity, a higher viscosity than that of the hydraulic fluid is required. For this reason, it is difficult to obtain the viscosity required for gear oil only with the phosphoric acid ester and the like.
Moreover, although improvement of the flame retardance in gear oil is examined, there are few examples put into practical use and the further improvement is requested | required about the flame retardance and self-extinguishing property in gear oil.

This invention is made | formed in view of such a situation, and makes it a subject to achieve the following objectives.
That is, an object of the present invention is to provide a gear oil composition that can be used in various applications that can be ignited and is excellent in flame retardancy and self-extinguishing properties.

In order to achieve the above object, the present invention provides the following gear oil composition.
<1> It is a gear oil composition, Comprising: As base oil, (A) 20-70 mass% of phosphorus containing compounds whose kinematic viscosity in 40 degreeC is 1-1000 mm < ² > / s with respect to base oil whole quantity, And (B) 1 or more types selected from the polyol ester and complex ester whose kinematic viscosity in 40 degreeC is 100-30,000 mm < ² > / s and whose flash point is 200 degreeC or more to base oil whole quantity. 30 to 80% by mass,
(C) The tetrazole is 0.5 to 5.0% by mass with respect to the total amount of the gear oil composition, and
(D) The extreme pressure agent containing sulfur is contained in an amount of 0.1 to 10% by mass based on the total amount of the gear oil composition,
And the kinematic viscosity in 40 degreeC of this gear oil composition is 50-1,000 mm < ² > / s, The gear oil composition characterized by the above-mentioned.

<2> The gear oil composition according to <1>, wherein the phosphorus-containing compound of the component (A) is a compound represented by the following formula (1).

In formula (1), R ¹ , R ² and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, which may be the same or different, and a is 0 or 1 Is an integer.

<3> The gear oil composition according to <2>, wherein a in Formula (1) is 1.

<4> The gear oil composition according to any one of <1> to <3>, wherein the extreme pressure agent containing sulfur as the component (D) is a sulfur-phosphorus extreme pressure agent.

  ADVANTAGE OF THE INVENTION According to this invention, the gear oil composition which can be used for the various uses with a possibility of ignition, and was excellent in the flame retardance and self-extinguishing property can be provided.

As a result of intensive studies, the inventors have formulated (A) a phosphorus-containing compound, and (B) at least one of a polyol ester and a complex ester, respectively, in a predetermined ratio and added as a base oil. It has been found that a gear oil composition excellent in flame retardancy and self-extinguishing properties can be obtained by containing predetermined amounts of (C) tetrazoles and (D) an extreme pressure agent containing sulfur as agents. Moreover, it discovered that flame retardance and self-extinguishing property were remarkably improved by using the phosphorus containing compound of a specific structure among phosphorus containing compounds.
Hereinafter, each component, property, and use of the gear oil composition of the present invention will be described in detail.

1. Base oil (A) Phosphorus-containing compound In the gear oil composition of the present invention, as a component of the base oil, (A) a phosphorus-containing compound having a kinematic viscosity at 40 ° C. of 1 to 1,000 mm ² / s (hereinafter, “ (Also referred to as “component (A)”). By containing the component (A) as a base oil, the flame retardancy and self-extinguishing properties of the gear oil composition are improved.

The phosphorus-containing compound has a kinematic viscosity at 40 ° C. (hereinafter also referred to as “40 ° C. kinematic viscosity”) in the JIS K2283 kinematic viscosity test method (40 ° C.) of 1 to 1,000 mm ² / s, preferably 5 It is -500 mm < ² > / s, More preferably, it is 10-250 mm < ² > / s, Especially preferably, it is 20-130 mm < ² > / s, Most preferably, it is 40-110 mm < ² > / s. When the 40 ° C. kinematic viscosity of the phosphorus-containing compound is less than 1 mm ² / s, the flame retardancy and the self-extinguishing property tend to be low, and the kinematic viscosity required as gear oil may not be appropriately adjusted. is there. If the 40 ° C. kinematic viscosity of the phosphorus-containing compound exceeds 1,000 mm ² / s, the kinematic viscosity of the gear oil composition tends to increase, and the stirring resistance tends to increase, which is necessary for driving the gear. Tend to increase.

Examples of the phosphorus-containing compound include phosphine, phosphinite, phosphonite, phosphite, phosphine oxide, phosphinate, phosphonate, phosphate, acid phosphate, thiophosphate, and the like.
Among these, the phosphorus-containing compound is preferably a compound represented by the following general formula (1) from the viewpoint of flame retardancy and self-extinguishing properties.

In the general formula (1), R ¹ , R ² and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, and may be the same or different, and a is 0 Or it is 1.
From a more effectively suppressing the corrosion of steel members, it is preferable that at least one of R ^1, R ² and R ³ is a hydrocarbon group, all of R ^1, R ² and R ³ More preferably, it is a hydrocarbon group.

When the hydrocarbon groups R ¹ , R ² and R ³ each have 24 or less carbon atoms, the fluidity of the base oil is further improved. The number of carbon atoms of the hydrocarbon groups R ¹ , R ² and R ³ is preferably 1-18, more preferably 2-15, and particularly preferably 3-12. Moreover, the total amount of carbon atoms of R ¹ , R ² and R ³ is preferably 4 to 45, more preferably 6 to 40, and particularly preferably 8 to 35.
The hydrocarbon group may be an aromatic hydrocarbon group, an alicyclic hydrocarbon group, or an aliphatic hydrocarbon group, but preferably an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or these A combined group, more preferably an aromatic hydrocarbon group, or a group obtained by combining an aliphatic hydrocarbon group and an aromatic hydrocarbon group, and particularly preferably an aromatic hydrocarbon group.

The aliphatic hydrocarbon group may be linear or branched. Specific examples of the aliphatic hydrocarbon group include an ethyl group, a propyl group, a butyl group, an octyl group, an isodecyl group, a dodecyl group, a tridecyl group, a stearyl group, and an oleyl group.
Specific examples of the aromatic hydrocarbon group include phenyl group, cresyl group, xylyl group, ethylphenyl group, isopropylphenyl group, butylphenyl group, octylphenyl group and the like.

  Moreover, although a in the said General formula (1) is 0 or 1, the case where a is 1 is more excellent in a flame retardance and self-extinguishing property.

(A) Content of the phosphorus containing compound which is a component is 20-70 mass% with respect to the base oil whole quantity, Preferably it is 20-50 mass%, More preferably, it is 30-50 mass%. When the phosphorus-containing compound is less than 20% by mass, sufficient flame retardancy and self-extinguishing properties cannot be obtained. Further, the tetrazole, which is an essential component of the present invention, tends to be difficult to be stably dissolved in gear oil. On the other hand, if the phosphorus-containing compound exceeds 70% by mass, thermal stability, which is a necessary performance as gear oil, tends to be reduced.
The phosphorus-containing compound as the component (A) can be used alone or in combination of two or more.

(B) Polyol ester, complex ester The gear oil composition of the present invention has, as a base oil, (B) a kinematic viscosity at 40 ° C. of 100 to 30,000 mm ² / s in addition to the component (A), and One or more selected from polyol esters and complex esters (hereinafter also simply referred to as “component (B)”) having a flash point of 200 ° C. or higher is used.
When the gear oil composition contains the component (B) as a base oil, the kinematic viscosity suitable for the gear oil can be adjusted without impairing flame retardancy and self-extinguishing properties. Furthermore, the component (B) is excellent in compatibility with the component (A).

Polyol esters and complex esters are both the 40 ° C. kinematic viscosity in JIS K2283 Kinematic Viscosity Test Method (40 ° C.), are used those 100~30,000mm ² / s, preferably 150~10,000mm ² / s, particularly preferably from 200 to 5,000 mm ² / s is used.
When the 40 ° C. kinematic viscosity of the polyol ester or complex ester is less than 100 mm ² / s, sufficient flame retardancy and self-extinguishing properties cannot be obtained, and the kinematic viscosity required as gear oil may not be adjusted appropriately. In addition, when a low viscosity phosphorus-containing compound is used as the component (A), if a polyol ester or complex ester having a low kinematic viscosity is used, a sufficient amount of the phosphorus-containing compound cannot be contained when adjusting to the kinematic viscosity of the present invention. In some cases, sufficient flame retardancy and self-extinguishing properties cannot be obtained.
On the other hand, when the 40 ° C. kinematic viscosity of the polyol ester or complex ester is greater than 30,000 mm ² / s, the compatibility with the component (A) tends to be low, and the kinematic viscosity as gear oil increases. The stirring resistance tends to increase, and the force required to drive the gear tends to increase.

  Further, the flash points of the polyol ester and the complex ester are each 200 ° C. or higher, preferably 220 ° C. or higher, particularly preferably 240 ° C. or higher, in the flash point test according to JIS K2265 Cleveland open method. When the flash point is less than 200 ° C., sufficient flame retardancy and self-extinguishing properties cannot be obtained.

The polyol ester used as the component (B) is an ester composed of an aliphatic monovalent carboxylic acid and a polyhydric alcohol.
Examples of the aliphatic monovalent carboxylic acid that forms the polyol ester include aliphatic monovalent carboxylic acids having 4 to 24 carbon atoms. The number of carbon atoms of the aliphatic monovalent carboxylic acid is more preferably 8-22, and still more preferably 14-22. In order to adjust the 40 ° C. kinematic viscosity, which is essential as the component (B), within the above range, the carbon number range is preferably within the above range.
The aliphatic monovalent carboxylic acid may be either a straight chain or a branched chain.
The aliphatic monovalent carboxylic acids forming one molecule of ester may be the same or different.

  Examples of the polyhydric alcohol that forms the polyol ester include bivalent or higher alcohols. Divalent to tetravalent alcohols are preferable, and trivalent to tetravalent alcohols having 3 to 6 carbon atoms are more preferable. Examples of such polyhydric alcohols include glycerol, erythritol, polyhydric alcohols having a neopentyl structure (trimethylolethane, trimethylolpropane, pentaerythritol, etc.).

  The polyol ester may be a complete ester in which all of the hydroxyl groups of the polyhydric alcohol are esterified, or a partial ester in which at least one of the hydroxyl groups remains in the form of a hydroxyl group that is not esterified. Also good. In addition, esterification can be performed by a conventionally well-known method.

The complex ester used as the component (B) is an ester of an aliphatic monovalent carboxylic acid or divalent carboxylic acid and a polyhydric alcohol.
Examples of the aliphatic monovalent carboxylic acid forming the complex ester include aliphatic monovalent carboxylic acids having 4 to 24 carbon atoms. The number of carbon atoms of the aliphatic monovalent carboxylic acid is more preferably 8-22, and still more preferably 14-22.
Specific examples of the aliphatic monovalent carboxylic acid include butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. In order to adjust the 40 ° C. kinematic viscosity, which is essential as the component (B), within the above range, the range of the carbon number of the aliphatic monovalent carboxylic acid is preferably within the above range. The aliphatic monovalent carboxylic acid may be linear or branched. In addition, the aliphatic monovalent carboxylic acids forming one molecule of ester may be the same or a mixture of two or more.

  Examples of the aliphatic divalent carboxylic acid forming the complex ester include aliphatic divalent carboxylic acids having 4 to 12 carbon atoms. The carbon number of the aliphatic divalent carboxylic acid is more preferably 8-12. Specific examples of the aliphatic divalent carboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and the like. In order to adjust the 40 ° C. kinematic viscosity, which is essential as the component (B), within the above range, the range of the carbon number of the aliphatic divalent carboxylic acid is preferably within the above range. The aliphatic divalent carboxylic acid may be linear or branched. In addition, the aliphatic divalent carboxylic acid forming one molecule of ester may be the same or a mixture of two or more.

  As the polyhydric alcohol forming the complex ester, those having 3 to 6 carbon atoms are preferable. Examples of such polyhydric alcohols include glycerol, erythritol, polyhydric alcohols having a neopentyl structure (trimethylolethane, trimethylolpropane, pentaerythritol, etc.).

  The complex ester may be a complete ester in which all of the hydroxyl groups of the polyhydric alcohol are esterified, or a partial ester in which at least one of the hydroxyl groups remains in the form of a hydroxyl group that is not esterified. good. In addition, esterification can be performed by a conventionally well-known method.

  As the component (B), any component selected from the above-described polyol esters and complex esters can be preferably used, but from the viewpoint of good compatibility with the component (A). The number of ester groups is preferably 3 or more.

  (B) The compounding quantity with respect to the base oil whole quantity of a component is 30-80 mass%, Preferably it is 30-70 mass%, More preferably, it is 40-70 mass%. When the blending amount of the component (B) is less than 30% by mass with respect to the total amount of the base oil, the kinematic viscosity of the gear oil composition defined in the present invention may not be appropriately adjusted. On the other hand, when the blending amount of the component (B) exceeds 80% by mass with respect to the total amount of the base oil, the blending amount of the phosphorus-containing compound as the component (A) is relatively small, and the flame retardancy and self-extinguishing properties are reduced. A sufficient effect cannot be obtained.

  In addition, the polyol ester and complex ester used as the component (B) may be used alone or in combination. Further, two or more polyol esters, two or more complex esters, or a combination thereof may be used.

  The base oil of the gear oil composition of the present invention may contain other base oils other than the above components (A) and (B), as long as the effects of the present invention are not impaired. Tetrazoles, which are additives, are water-soluble and dissolve to some extent in phosphate esters, but basically do not dissolve in hydrocarbon oils, so it is preferable that they do not substantially contain other base oil components. .

2. Additive (C) Tetrazoles The gear oil composition of the present invention contains tetrazoles. Representative examples of tetrazoles include 1H-tetrazole, 5-amino-1H-tetrazole, 5-methyl-1H-tetrazole, 5-phenyl-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 2-methoxy-5- (5-trifluoromethyl-1H-tetrazol-1-yl) -benzaldehyde, 1-methyl-5-ethyl-1H-tetrazole, 1-methyl-5-mercapto-1H-tetrazole, 5, Examples include 5′-bi-1H-tetrazole diammonium salt and 5,5′-azobis-1H-tetrazole. Preferably, an aromatic ring is contained in the structural formula, and typical examples include 5-phenyl-1H-tetrazole, 1-phenyl-5-mercapto-1H-tetrazole, 2-methoxy-5- (5- And trifluoromethyl-1H-tetrazol-1-yl) -benzaldehyde. Tetrazoles represented by the above may be added singly or in combination of two or more.
The amount of tetrazole added is 0.5-5% by mass, preferably 1-5% by mass, based on the total amount of the gear oil composition. If the amount of tetrazole added is less than 0.5% by mass, self-extinguishing properties cannot be obtained, and if it exceeds 5% by mass, it is difficult to dissolve in gear oil.

(D) Extreme Pressure Agent Containing Sulfur The gear oil composition of the present invention contains (D) an extreme pressure agent containing sulfur (hereinafter also simply referred to as “component (D)”) as an extreme pressure agent. .
As said (D) component, a sulfur type extreme pressure agent and a sulfur- phosphorus type extreme pressure agent are mentioned, for example, A sulfur- phosphorus type extreme pressure agent is preferable from a wear-resistant viewpoint.

(I) Sulfur-based extreme pressure agent Examples of the sulfur-based extreme pressure agent include hydrocarbon sulfides and sulfurized fats and oils.
As said hydrocarbon sulfide, the hydrocarbon sulfide represented by General formula (2) or General formula (3) is mentioned.

In the general formula (2) and the general formula (3), R ⁴ represents a monovalent hydrocarbon group (for example, a linear or branched saturated or unsaturated group having 2 to 20 carbon atoms such as an alkyl group or an alkenyl group). Represents a saturated aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 26 carbon atoms, and R ⁵ represents a divalent hydrocarbon group (for example, a linear or branched saturated or branched group having 2 to 20 carbon atoms) An unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 26 carbon atoms).
Moreover, in general formula (2) and general formula (3), b is an integer greater than or equal to 1, and each b may be the same or different in a repeating unit, and c represents 0 or an integer greater than or equal to 1.

Specific examples of the monovalent hydrocarbon group represented by R ⁴ include ethyl group, propyl group, butyl group, nonyl group, dodecyl group, propenyl group, butenyl group, phenyl group, tolyl group, hexylphenyl group, A benzyl group etc. are mentioned.
Specific examples of the divalent hydrocarbon group represented by R ⁵ include an ethylene group, a propylene group, a butylene group, and a phenylene group.

  Specific examples of these hydrocarbon sulfides include polysulfide compounds such as diisobutyl disulfide, dioctyl polysulfide, di-tert-butyl polysulfide, di-tert-nonyl polysulfide and dibenzyl polysulfide, and polyisobutylene and terpenes. Sulfurized olefins obtained by sulfurizing sulfur such as sulfur, reaction products of isobutylene and sulfur, and compounds presumed to have chemical formulas of general formula (4) and general formula (5) Can be mentioned.

  In general formula (4), b and c are the same as b and c in general formula (2).

  In general formula (5), b and c are the same as b and c in general formula (3).

Examples of the sulfurized fats and oils include reaction products of fats and sulfur.
Here, as fats and oils, animal and vegetable fats and oils such as lard, beef tallow, whale oil, palm oil, coconut oil, rapeseed oil and the like can be mentioned.

(Ii) Sulfur-phosphorus extreme pressure agent Examples of the sulfur-phosphorus extreme pressure agent include those obtained by combining the above sulfur-based extreme pressure agent and phosphorus-based extreme pressure agent, and sulfur-phosphorus-based compounds. It is done.
Phosphorus extreme pressure agents combined with sulfur extreme pressure agents include phosphates, phosphites, and derivatives thereof. The phosphate and phosphite may be any of mono, di and triester, and the alcohol residue thereof is an alkyl group having 4 to 30 carbon atoms such as butyl, octyl, lauryl, stearyl or oleyl group, carbon such as phenyl group, etc. Examples include an aryl group having 6 to 30 carbon atoms, an alkyl-substituted aryl group having 7 to 30 carbon atoms such as methylphenyl and octylphenyl groups. Specific examples of the phosphorus extreme pressure agent include tributyl phosphate, monooleyl phosphate, dioctyl phosphate, dioleyl phosphite, diphenyl phosphite, tricresyl phosphite and the like. These derivatives include amine salts such as stearylamine salts, oleylamine salts, coconutamine salts, and the like.

  Examples of the sulfur-phosphorus compound include thiophosphite, thiophosphate, and derivatives thereof. The thiophosphite may be mono, di, or trithiophosphite. The thiophosphate may be mono, di, tri, or tetrathiophosphate. Thiophosphite and thiophosphate may be mono-, di- or triesters, and the alcohol residue thereof is an alkyl group having 4 to 30 carbon atoms such as butyl, octyl, lauryl, stearyl or oleyl group, or phenyl group. And aryl groups having 6 to 30 carbon atoms such as alkyl substituted aryl groups having 7 to 30 carbon atoms such as methylphenyl and octylphenyl groups. Examples of specific compounds include tributyl thiophosphate, monooleyl thiophosphate, dioctyl thiophosphate, tricresyl thiophosphate, and the like. Examples of these amine salts include stearylamine salts, oleylamine salts, and coconut amine salts. Examples of the thiophosphite and thiophosphate derivatives include amine salts with the above thiophosphites and thiophosphates, metal salts, reaction products with fatty acids, and the like, and dithiophosphate esters represented by the following general formula (6) A compound or the like can also be used.

In general formula (6), R ⁶ and R ⁷ each represent a hydrocarbon group having 2 to 20 carbon atoms, and may be the same or different. R ⁸ represents a divalent aliphatic hydrocarbon having 1 to 17 carbon atoms and may be linear or branched. X represents hydrogen or a carboxyl group.

Content of (D) component demonstrated above needs to be 0.1-10 mass% with respect to the whole quantity of the gear oil composition of this invention.
The content of the component (D) is more preferably 0.1 to 8% by mass, particularly preferably 0.2 to 5% by mass, further preferably 0.5 to 3% by mass, Preferably it is 0.8-2 mass%. When the content of the component (D) is less than 0.1% by mass, it tends to be difficult to obtain the extreme pressure performance required as a gear oil composition. Since the compounding ratio of the compound and (C) tetrazole is relatively small, flame retardancy and self-extinguishing properties may be reduced.
The said (D) component can be used individually by 1 type or in combination of 2 or more types.

(X) Other Additives The gear oil composition of the present invention comprises (A) component and (B) component base oil, (C) tetrazoles, and (D) extreme pressure agent containing sulfur, each in a predetermined amount. Although it mix | blends, another additive (optional component) can be mix | blended suitably as needed.
Other additives include, for example, metal detergents such as alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates; alkenyl succinimides, alkenyl succinimide boronated modified products, benzylamine, alkyls Dispersants such as polyamines; various antiwear agents such as zinc-based, amine-based, ester-based; polymethacrylate-based, ethylene-propylene copolymer, styrene-isoprene copolymer, hydride of styrene-isoprene copolymer or polyisobutylene Various viscosity index improvers such as: alkylphenols such as 2,6-di-tert-butyl-p-cresol, bisphenols such as 4,4′-methylenebis- (2,6-di-tert-butylphenol), n -Octadecyl-3- (4'-hydroxy- Various antioxidants such as phenolic compounds such as', 5'-di-tert-butylphenol) propionate, aromatic amine compounds such as naphthylamines and dialkyldiphenylamines; carboxylic acids such as stearic acid, dicarboxylic acids, metal soaps, Various rust inhibitors such as carboxylic acid amine salts, metal salts of heavy sulfonic acids, carboxylic acid partial esters of polyhydric alcohols; various corrosion inhibitors such as benzotriazole and benzimidazole; various antifoaming agents such as silicone oil; Can be mentioned.
The additive which becomes the above arbitrary components can be used individually by 1 type or in combination of 2 or more types.
In addition, as the compounding amount of the additive as an optional component, the effect of adding it is surely exerted, and added in an amount that does not impair flame retardancy and self-digestibility due to essential components such as phosphorus-containing compounds and tetrazoles. do it.

3. The kinematic viscosity of the gear oil composition kinematic viscosity invention of the gear oil composition, in JIS K2283 Kinematic Viscosity Test Method (40 ° C.), a 50 to 1000 mm ² / s, there preferably 50~800mm ² / s More preferably, it is 100-600 mm < ² > / s, Most preferably, it is 150-350 mm < ² > / s. When the 40 ° C. kinematic viscosity of the gear oil composition is less than 50 mm ² / s, flame retardancy and self-extinguishing properties tend to be low, and lubricity required for gear oil tends to be low. On the other hand, when the 40 ° C. kinematic viscosity of the gear oil composition exceeds 1,000 mm ² / s, the stirring resistance tends to increase, and the force necessary to drive the gear tends to increase.
In addition, the preparation method of the gear oil composition of this invention is not specifically limited, Essential component (A)-(D) may be mixed, and the additive used as an arbitrary component should just be mix | blended as needed. The mixing order of these components is not particularly limited.

4). Applications The gear oil composition of the present invention can be used in various applications where there is a possibility of ignition and flame retardancy is required. For example, it can be used for bearings and gears of industrial machines, metal processing, particularly preferably for gear parts of rolling mills, conveyor belt conveyors, turbines of power plants, construction machines, machine tools, ships and the like. In addition, although the composition of this invention is used suitably for gear oil, it can also be used for industrial lubricating oils, such as hydraulic oil, turbine oil, and compressor oil.

  Next, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by these examples.

The base oils and additives used for preparing the gear oil compositions in each Example and each Comparative Example are as follows.
The 40 ° C. kinematic viscosity was measured by the JIS K2283 kinematic viscosity test method, and the flash point was measured by the JIS K2265 Cleveland open method. Aroma% CA was determined by ASTM D3238 ring analysis. The refractive index, density, molecular weight and sulfur content required for the calculation were measured by JIS K0062 refractive index measurement method, JIS K2249 density test method, ASTM D2502 molecular weight test method, and JIS K2541 sulfur content test method.

<Base oil>
Phosphorus-containing compound (A-1) as component (A) Trixylenyl phosphate, 40 ° C. kinematic viscosity: 46 mm ² / s
(In the general formula (1), R ^{1 to} R ³ are xylyl groups and a is 1)
(A-2) Aryl phosphate, 40 ° C. kinematic viscosity: 99 mm ² / s
(In the general formula (1), R ^{1 to} R ³ are alkylphenyl groups, a is 1; trade name: Firequel 550, manufactured by Cosmo Oil Lubricants Co., Ltd.)

(B) Component ester (B-1) Complex ester (trade name: PRIOLUBE 1851, manufactured by Unikema), 40 ° C. kinematic viscosity: 512 mm ² / s, flash point: 290 ° C.
(B-2) Complex ester (trimethylolpropane fatty acid condensed ester), 40 ° C. kinematic viscosity: 2,750 mm ² / s, flash point: 290 ° C.
(B-3) Complex ester (trade name: TMP05 / 1000, manufactured by Cognis), 40 ° C. kinematic viscosity: 950 mm ² / s, flash point: 320 ° C.
(B-4) Complex ester (trade name: PRIOLUBE 3986, manufactured by Unikema), 40 ° C. kinematic viscosity: 47,000 mm ² / s, flash point: 325 ° C.

<Additives>
(C) Tetrazoles, triazoles (C-1) 1-phenyl-5-mercapto-1H-tetrazole (C-2) 5-phenyl-1H-tetrazole (C-3) benzotriazole

(D) Extreme pressure agent (D-1) Sulfurized olefin (19% sulfur content)
(D-2) Acid phosphate amine salt (D-3) β-dithiophosphorylated propionic acid (in general formula (6), R ⁶ and R ⁷ are isobutyl groups, R ⁸ is carbon number 2 and X is a carboxyl group)

(X) Other additives Antioxidant: Octylated diphenylamine

<Evaluation method>
1. Compatibility The base oil component was heated and mixed, and then allowed to stand at room temperature for 1 week to confirm whether or not the base oil component was separated. What was not isolate | separated was evaluated as (circle) and what isolate | separated was evaluated as x.

2. Flame retardancy and self-extinguishing properties As shown in Fig. 1, after half of medical gauze (100% cotton material, 7cm x 15cm) is soaked with the sample, it is hung with the part soaked with the sample up, It was ignited from the lower part where the sample was not attached, and the presence or absence of continued combustion was evaluated. Those that were extinguished within 30 seconds after ignition were evaluated as “◯”, and those that were continuously burned for 30 seconds or more were evaluated as “X”.
○ is excellent in flame retardancy and self-extinguishing properties, and x is inferior in self-extinguishing properties.

3. Load bearing performance Extreme pressure and wear resistance were evaluated by a load bearing test. The load resistance test was based on DIN 51354-2 using an FZG gear tester. That is, after applying a load in accordance with the standard to the gear, a test was performed until the speed reached 21700 at a gear rotation speed of 1440 rpm (this is the one stage). The load stage is raised stepwise, and the total area width of wear scratches (scuffing, scoring) on the 16 tooth surfaces of the pinion at the end of 12 stages (pinion torque 534.5 Nm) is less than 20 mm. evaluated.

<Examples 1-7>
A gear oil composition was prepared by blending a base oil (mass% with respect to the whole base oil) and an additive (mass% with respect to the whole composition) in the proportions shown in Table 1. Various performances of these gear oil compositions were evaluated, and the results are shown in Table 1.

<Comparative Examples 1-7>
A base oil (mass% with respect to the whole base oil) and an additive (mass% with respect to the whole composition) were blended in the ratios shown in Table 2 to prepare gear oil compositions. Various performances of these gear oil compositions were evaluated, and the results are shown in Table 2.

As shown in Tables 1 and 2, Examples 1 to 4 in which gear oil compositions were prepared based on the components and blending amounts of the present invention were all evaluated for compatibility, self-extinguishing properties, and load bearing performance. It is good.
On the other hand, Comparative Example 1 using a complex ester alone as a base oil, Comparative Example 2 containing no tetrazole, and Comparative Example 3 having a small amount of tetrazole added have a kinematic viscosity necessary as a gear oil, but are self-extinguishing. Sex cannot be obtained. Moreover, although the comparative example 4 which does not contain a sulfur- phosphorus type extreme pressure agent can achieve compatibility and self-extinguishing property, it cannot obtain load bearing performance. Furthermore, in Comparative Example 5 using a base oil in which a phosphorus-containing compound and a complex ester having a too high kinematic viscosity are combined, no compatibility is obtained. In Comparative Example 6 in which the phosphorus-containing compound is 15%, self-extinguishing properties cannot be obtained. Further, in Comparative Example 7 containing nitrogen compounds other than tetrazoles, no compatibility is obtained.

It is the figure which showed notionally the combustion test in an Example.

Claims (4)

A gear oil composition comprising:
As a base oil, (A) 20-70 mass% of phosphorus containing compounds whose kinematic viscosity in 40 degreeC is 1-1000mm < ² > / s with respect to base oil whole quantity, and (B) kinematic viscosity in 40 degreeC 30 to 80% by mass, based on the total amount of the base oil, containing at least one selected from polyol esters and complex esters having a flash point of 200 ° C. or higher and 100 to 30,000 mm ² / s,
(C) The tetrazole is 0.5 to 5.0% by mass with respect to the total amount of the gear oil composition, and
(D) The extreme pressure agent containing sulfur is contained in an amount of 0.1 to 10% by mass based on the total amount of the gear oil composition,
And the kinematic viscosity in 40 degreeC of this gear oil composition is 50-1,000 mm < ² > / s, The gear oil composition characterized by the above-mentioned. The gear oil composition according to claim 1, wherein the phosphorus-containing compound of the component (A) is a compound represented by the following formula (1).

(In the formula (1), R ¹ , R ² and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 24 carbon atoms, and may be the same or different, and a is 0 or It is an integer of 1.)   The gear oil composition according to claim 2, wherein a in the formula (1) is 1.   The gear oil composition according to any one of claims 1 to 3, wherein the extreme pressure agent containing sulfur as the component (D) is a sulfur-phosphorus extreme pressure agent.

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