JPH064868B2 - Molybdenum-containing lubricating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel oil-soluble molybdenum compound useful as a lubricating oil additive.

In particular, the present invention is an antioxidant property, an antiwear property, a friction relaxation property,
The present invention relates to a lubricating composition containing an oil-soluble molybdenum compound which is excellent in mineral oil solubility and particularly corrosive to metals such as copper and iron.

[Conventional technology and problems]

Conventionally, various compositions have been known as lubricating additives for engine oils, etc., but in recent years, the performance required for the lubricating additive has become more and more severe from the viewpoint of resource saving and energy saving. Zinc dithiophosphate (hereinafter referred to as ZDTP) has been generally used for improving wear resistance, etc., and also, Japanese Patent Publications 40-8426 and 44-27366.
Alternatively, as disclosed in JP-A-56-110796, dialkylphosphorodithionate oxymolybdenum sulfide (hereinafter referred to as Mo
-DTP) is also used.

Also, many molybdenum dithiocarbamate (hereinafter referred to as Mo-DTC) type compounds have been reported (Japanese Patent Publication No. 49-63).
62, Japanese Patent Sho 51-964, Japanese Patent Sho 53-61646, Japanese Patent Sho 56-1263
8 and others).

These known ZDTP, Mo-DTP and Mo-DTC each have some drawbacks with respect to the performance required as a lubricating additive such as antioxidation property, antiwear property, friction mitigation property and solubility in mineral oil, etc. A major common drawback is that it is highly corrosive to metals.

[Means for Solving Problems] Conventionally, it has been essential that an organic molybdenum compound useful as a lubricating additive contains a sulfur atom in its molecule. In other words, it has been said that the molybdenum and sulfur contained in the molecule produce molybdenum disulfide on the lubrication surface to exert the lubrication performance. However, the present inventors believe that the active sulfur atom contained in the molecule may have an adverse effect on the corrosion of the metal, and are keen to solve these two contradictory points. I did a research. As a result, surprisingly, the product of the reaction of hexavalent molybdic acid and phosphoric acid ester has almost no performance as a lubricating additive by itself, but when combined with a sulfur-containing compound, very good lubrication is achieved. It turned out to have performance.

That is, the lubricating composition of the present invention comprises one or two selected from molybdenum trioxide, molybdic acid or alkali salts thereof.
A hexavalent molybdenum compound of one species or more, containing a novel oil-soluble molybdenum compound produced by reacting with a mono- or diphosphorus ester, and a specific sulfur-containing compound as an essential component, and has been conventionally used. ZDTP, Mo-DTP, Mo-DTC
It has a lubrication performance equal to or higher than that and is excellent in metal corrosion.

The molybdic acid used here may be an acid or an alkali salt thereof, or molybdenum trioxide, but it is preferable to contain the molybdic acid alkali salt to such an extent that the whole is uniformly dissolved in water. Examples of the alkali salt used here include soda salt, potassium salt, ammonium salt and the like.

The concentration of the molybdenum compound is not particularly limited, but it is preferable to be present in water in an amount of about 5 to 40% by weight, preferably about 10 to 20% by weight, in order to facilitate the reaction with the phosphoric acid ester and the post-treatment. In addition, it is not always necessary to completely dissolve it, and the reaction proceeds even in a dispersed state.

The reaction between the hexavalent molybdenum compound and the phosphoric acid ester is first carried out by dropwise addition of the phosphoric acid ester between room temperature and 100 ° C. in about 1 hour. The molar ratio of the molybdenum compound and the phosphoric acid ester is preferably between 1: 1 and 1: 4. When the amount of the phosphoric acid ester is less than this, the oil solubility and the yield are poor, and when it is more than the unreacted phosphoric acid. The ester will remain.

After that, it is neutralized with an amount of acid corresponding to the alkali of the alkali salt of molybdic acid used at the beginning, and reacted at 100 ° C for 2 to 10 hours. Finally, if necessary, a solvent is used to separate water to obtain an oil-soluble molybdenum compound.

The phosphoric acid ester used is one produced from various hydroxyl compounds and phosphorus pentoxide, etc., and as this hydroxyl compound, methanol, ethanol, n-propanol, n-butanol, n-octanol, lauryl alcohol, stearyl alcohol Such as straight chain alcohols, isopropanol, isobutanol, 2-ethylhexyl alcohol, branched tridecyl alcohols such as branched alcohols, cyclohexanol, alicyclic alcohols such as 2-methylcyclohexanol, benzyl alcohol, aromatic ring substituents such as alkylphenols Examples thereof include alcohols and phenols. As the hydroxyl compound, those having 3 to 24 carbon atoms are preferable, and as this phosphoric acid ester, monosubstituted or disubstituted so-called acid phosphate can be used, and trisubstituted ester cannot be used. Further, in the case of 1-substitution and 2-substitution, the 2-substitution ester is superior in terms of yield and solubility of mineral oil.

Any acid can be used as the neutralizing agent, but mineral acids such as hydrochloric acid and sulfuric acid are more preferable in terms of cost and separability of the aqueous layer after the reaction.

The compound containing sulfur, which is the other essential component of the present invention, includes dibenzyl disulfide, the general formula (I) (In the formula, R ₁ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different.) A tetraalkylthioperoxyphosphate represented by the following general formula (II) (In the formula, R ₂ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different.) Zinc dithiophosphate represented by the following general formula (III) (Wherein R ₃ is a hydrocarbon group having 7 to 24 carbon atoms and may be the same or different, and X is S or O), and molybdenum dithiocarbamate represented by the following general formula (IV) (Wherein R ₄ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different, and X is S or O), and a sulfur-containing compound selected from the group consisting of molybdenum dithiophosphates can be used. is there. Among them, when the compound represented by the general formula (I), (II), (III) or (IV) is used, the composition is excellent especially in the friction coefficient lowering ability and the abrasion preventing ability.

The ratio of the molybdenum compound to the sulfur-containing compound is 0.5 or more, preferably 1.5 or more, of sulfur atom to 1 atom of molybdenum. There is no particular upper limit, and a sulfur-containing compound may be added in a large amount as an additive for a lubricant. However, the upper limit is usually about 50 molybdenum / sulfur.

The composition of the present invention is useful as a lubricant additive. The lubricant is usually composed of a base oil or a base, various additives and the like added depending on the application, and the composition of the present invention may be appropriately used in combination with these base oils / bases and additives. it can.

Examples of the base oil / base include natural oils such as animal oils, vegetable oils, oils obtained from petroleum, paraffinic oils, naphthenic oils, and mixtures thereof.

Synthetic lubricating oils include olefin polymers and copolymers (eg, polybutylene, polypropylene, propylene-
Isobutylene copolymer, polybutylene chloride, poly (1-
Hexane), poly (1-octene), poly (1-decene), etc. and mixtures thereof), alkylbenzene (for example, dodecylbenzene, tetradodecylbenzene, dinonylbenzene, di (2-ethylhexyl) benzene, etc.),
Included are hydrocarbon oils and halogen-substituted hydrocarbon oils such as polyphenyls (eg, biphenyl, terphenyl, alkyl polyphenyls, etc.), alkyl diphenyl ethers and alkyl diphenyl diphenyls and their derivatives, analogs and homologs and the like. Mention may be made of the oils obtained by the polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers, as well as their mono- or polycarboxylic acid esters or diesters. Also included are esters of dicarboxylic acids (eg, phthalic acid, succinic acid, alkylsuccinic acids and alkenylsuccinic acids, sebacic acid, adipic acid, linoleic acid dimers, etc.) and various alcohols. Useful esters also include those made from polyhydric alcohol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol.
Also, silicic oils such as polyalkyl-, polyaryl-, polyalkoxy- or polyaryloxy-siloxane oils and silicate oils, liquid esters of acids containing phosphorus (TC
P, TOP, decylphosphonic acid diethyl ester) and the like.

Examples of various additives to be added depending on the use include, for example, ash-forming or ashless type auxiliary detergents and dispersants, corrosion and antioxidants, pour point depressants, extreme pressure agents, oiliness agents, colorants and deodorants. Examples include foaming agents.

Ash producing detergents are carbon and phosphorus obtained by treating alkali metal or alkaline earth metal sulfuric acid, carboxylic acid, or olefin polymer with a phosphorus agent such as phosphorus trichloride, phosphorus pentasulfide, phosphorus trichloride and sulfur. Is represented by a fat-soluble neutral or basic salt such as an organic phosphoric acid having at least one bond directly bonded to. The most commonly used are sodium, potassium, lithium, calcium, magnesium,
It is a salt of strontium and barium.

Examples of the ashless detergent include carboxylic acid-based dispersants, amine dispersants, Mannich dispersants, decyl methacrylate, vinyl decyl ether, and fat-soluble monomers such as high molecular weight olefins and polar such as aminoalkyl acrylates. Examples thereof include a copolymer with a monomer having a certain substituent.

Oiliness agents, extreme pressure agents, corrosion and antioxidants are represented by the following.

1) chlorinated aliphatic hydrocarbons 2) benzyl disulfide, bis (chlorobenzyl) disulfide,
Dibutyl tetrasulfide, sulfurized methyl ester of olefinic acid,
Organic sulfides and polysulfides of sulfurized alkylphenols, dipentene sulfides and terpenes sulfides 3) Phosphorus hydrocarbons such as reaction products of phosphorus sulfide with turpentine and methyl olefinate 4) Dibutyl, diheptyl, dicyclohexyl, pentyl phosphite Phenyl, dipentylphenyl, dioctyl, tridecyl, distearyl, dimethylnaphthyl, diisobutyl-substituted phenyl and other dihydrocarbons and trihydrocarbons Phosphorus ester mainly containing phosphite ester, tricresyl phosphate, trioctyl phosphate, tributyl phosphate, Phosphoric acid esters such as triphenyl phosphate and nonyl phenyl phosphate 5) Zinc dioctylcarbamate, zinc diisoamyldithiocarbamate and barium heptylphenyldithiocarbamate, diii Antimony amyldithiocarbamate, ditridecyldithiocarbamate oxymolybdenum sulphide, di-2-ethylhexyl dithiocarbamate oxymolybdenum sulphide, thiocarbamate metal salts such as dibutylbatiocarbacarbamoyl sulphide oxymolybdenum 6) Dicyclohexylphosphorodithioate zinc, dioctylphosphoro Zinc dithioate, barium di (heptylphenyl) phosphorodithioate, cadmium dinonylphosphorodithioate, and zinc salt of phosphorodithioate obtained by reaction of phosphorus pentasulfide with an equimolar mixture of isopropyl alcohol and n-hexyl alcohol, etc. Group II metal salts of phosphorodithioic acid, such as phosphorodithioic acid sulfurized oxymolybdenum salt 7) oleyl alcohol, stearyl alcohol, stearic acid, isostearic acid, o Oily agents such as in acid Among these, compounds containing sulfur will be used also as a compound containing a is one sulfur requirements of the present invention.

The application of the lubricant using the composition of the present invention is not particularly limited, and specific applications include automobile and truck engines, two-cycle engines, piston engines for aircraft, diesel engines for ships and locomotives, and the like. Crankcase lubricating oil for internal combustion engines of spark ignition type and compression ignition type, lubricating oil for gas engine, stationary power engine and turbine, automatic transmission liquid, transaxle lubricant, gear lubricant, metalworking lubricant, hydraulic liquid Further, other lubricating oils and grease compositions can be exemplified.

〔Example〕

Example 1 1 mol of sodium molybdate under a nitrogen stream and 540 ml of water
2 mol of dioctyl phosphate was added dropwise over 1 hour, and 1 mol of 20% sulfuric acid was added dropwise over 1 hour. Then, the temperature was raised to 100 ° C., and the reaction was further performed for 10 hours. After cooling the reaction solution, 300 ml of n-hexane was added, followed by washing with water and finally desolvation under reduced pressure to obtain 745 g of a pale blue oily product. Molybdenum content is 10.7%
And the yield for molybdenum was 83.0%.

Example-2 In the same manner as in Example 1, except that ditridecyl phosphate was used instead of dioctyl phosphate, 975 g of a light green oily product was obtained. Molybdenum content is 9.0%
And the yield for molybdenum was 91.5%.

Example-3 In the same manner as in Example 1, except that n-butyl phosphate was used instead of dioctyl phosphate, 495 g of a pale green oily product was obtained. The molybdenum content was 16.6% and the yield for molybdenum was 85.6%.

Example-4 The compounds obtained in Examples 1, 2 and 3 and commercially available Mo-DTP and Mo-DTC were used as commercially available engine oils (SD class 10w-
30, sulfur content 0.24% by weight) 0.1 as molybdenum content
It was melted in a weight percentage, put in a copper plate, and heated at 100 ° C. for 3 hours to test the corrosiveness with respect to the copper plate (based on ASTM D-130).

The results are shown in Table 1.

Example-5 The antioxidant properties and metal corrosion properties of the compounds obtained in Examples-1 to 3 and comparative products were compared by an oil deterioration test by the TOST method.

Test method A test based on the JIS-K-2514 turbine oil oxidation stability test. 98
C. × 480 hours, catalyst; steel wire and copper wire, base oil; commercial gear oil (ISO viscosity 220, sulfur content 1.31% by weight), concentration; 0.1% by weight as molybdenum. The results are shown in Table 2.

Example-6 A composition obtained by mixing the compounds obtained in Examples 1 to 3 and various sulfur-containing compounds was dissolved in 150 neutral oil as a molybdenum content of 0.06% by weight, and the antiwear property was measured by a shell four-ball tester. (Displayed as the diameter of the wear mark after 30 minutes at 1,800 rpm with an oil temperature of 80 ° C and a load of 40 kg). The wear coefficient was measured with a pendulum type oiliness tester (oil temperature 80 ° C., load 600 g, average of 50 times).

The results are shown in Table 3.

Example-7 The compounds obtained in each Example and Comparative Example were measured for their friction reducing effect with a reciprocating vibration friction tester (oil temperature 120 ° C, load 2.2 kg).
f, 12.2kgf, 22.2kgf, frequency 500rpm, amplitude 2.5mm, concentration; Mo as 0.04% by weight, sulfur compound; S as 0.06% by weight, test piece material SUJ-2, test piece type;
Upper 3/4 inch ball, lower flat plate).

The results are shown in Table 4. Among the sulfur-containing compounds in Table 4, disulfide compounds, ZDTP, Mo-DTP, Mo-D
The same TC as in Table 3 was used.

[Effect of the Invention] The effect of the present invention is to provide a novel molybdenum phosphate ester complex, and by using this in combination with a sulfur-containing compound, it is possible to obtain a new molybdenum phosphate complex more than the conventionally used ZDTP or molybdenum-containing lubricating oil additive. The purpose of the present invention is to provide a lubricating oil additive having excellent antioxidative property, antiwear property, and friction mitigating property, and particularly excellent in metal corrosiveness. Since it is excellent in metal corrosiveness and is a hexavalent molybdenum compound, it can be an excellent additive against pitting wear and the like of various engine parts which are related to it.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C10M 137: 10 Z 9159-4H 139: 00 Z 9159-4H 135: 22) (C10M 159/12 125) : 10 137: 04) C10N 10:04 10:12 30:00 A 8217-4H 30:06 30:10 30:12 40:00 A 8217-4H Z 8217-4H 40:04 40:08 40:20 Z 8217-4H 40:25 (72) Inventor Fukushima 7-23, Higashiohisa, Arakawa-ku, Tokyo Within Asahi Denka Kogyo Co., Ltd. (72) Inventor Tamiji Kamakura 7-2, 35 Higashiohisa, Arakawa-ku, Tokyo Issued in Asahi Denka Kogyo Co., Ltd. (56) Reference JP-A-50-109902 (JP, A) JP-B-40-8426 (JP, B1)

Claims (2)

[Claims] 1. An oil-soluble molybdenum compound obtained by reacting one or more hexavalent molybdenum compounds selected from molybdenum trioxide, molybdic acid or an alkali salt thereof with a mono- or diphosphate ester. Dibenzyl disulfide, general formula (I) (In the formula, R ₁ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different.) A tetraalkylthioperoxyphosphate represented by the following general formula (II) (In the formula, R ₂ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different.) Zinc dithiophosphate represented by the following general formula (III) (Wherein R ₃ is a hydrocarbon group having 7 to 24 carbon atoms and may be the same or different, and X is S or O), and molybdenum dithiocarbamate represented by the following general formula (IV) (Wherein R ₄ is a hydrocarbon group having 3 to 24 carbon atoms and may be the same or different, and X is S or O), and a sulfur-containing compound selected from the group consisting of molybdenum dithiophosphates. A lubricating composition as an essential component. 2. The lubricating composition according to claim 1, wherein the phosphoric acid ester is a phosphoric acid diester having two hydrocarbon groups having 3 to 24 carbon atoms.