JPH03223295A - Zinc dialkyldithiophosphate and lubricating oil composition containing the same - Google Patents

Abstract

NEW MATERIAL:A compound mixture having >=4-6C primary alkyl groups, comprising, in terms of the peak area ratio for the signals of phosphorus nuclear magnetic resonance (<31>P-NMR), 60-85% of a basic zinc salt with such signals developed within the range 103.3-104.1ppm, 20-0% of a second basic zinc salt with such signals developed within the range 102.5-103.2ppm and 15-40 % of a neutral zinc salt. USE:An additive for lubricants, functional fluids, greases etc.; noncorrosive on metals (esp. copper), also high in thermal stability; therefore, causing no separation of the deteriorated products of metal salts even at elevated temperatures. PREPARATION:Firstly, a primary alcohol such as 2-methyl-1-butanol is allowed to react with phosphorus pentasulfide into a dialkyl dithiophosphate. Thence, this dialkyl dithiophosphate is further allowd to react with zinc oxide pref. in the presence of a mineral oil.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a dialkyldithiophosphate zinc salt and a lubricating oil composition containing the same, and more specifically to a lubricant 1, functional fluid, fuel, grease, plastic, paint, etc. The present invention relates to a zinc dialkyl dithiophosphate salt useful as an additive for a lubricating oil composition containing this salt and having excellent metal corrosion resistance, thermal stability, etc.

[Problems to be solved by conventional techniques and inventions] In recent years,
As mechanical devices improve, the performance requirements for the lubricants and functional fluids used are becoming more sophisticated. In particular, there is a demand for improved heat resistance to cope with the rise in temperature associated with harsher environments and use conditions, and longer life for maintenance-free operation.

In order to improve their heat resistance and extend their service life, metal salts of dialkyldithiophosphoric acids, especially zinc salts, are effective as antioxidants and extreme pressure agents and are widely used.

Incidentally, a problem often seen in recent years is corrosion of metal parts due to lubricants, particularly corrosion of steel parts. In addition, when used at high temperatures, there is a problem in that the moisture performance is inhibited due to precipitation of degraded products of Kinbo salt and deterioration of lubricating oil.

A method for producing dialkyl dithiophosphates using lubricants to reduce corrosion of metal parts, especially steel parts, was published in the Japanese Patent Publication No. 62.
Japanese Patent Application No. 24115 discloses a method of processing with phosphatide. If you use these salts,
Corrosion to steel parts (: reduced, but there is a problem with thermal stability.Furthermore, as a matter of course, a complicated TJ operation called phosphite treatment is required, and if this treatment is not performed,
Causes corrosion to copper m.

On the other hand, as zinc dialkyldithiophosphate, which has good oil solubility in lubricating oil and does not crystallize even when left, JP-A-47
-32005 publication describes a mixed basic zinc salt ((RO)zPss) sZn20H containing 3 to 14 different alkyl groups (R) and an average linear prime number of 3.5 to 4.5 and a mixed neutral zinc salt. A mixture of salts ((RO)2PSS)sZn is described. However, these salts also lack thermal stability, and there remain problems such as precipitation of degraded metal salts, deterioration of lubricating oil, and corrosion of steel parts.

The above basic zinc salt was analyzed by P''-NMR etc. [Chem, Tech (Leipzig
)3 B(4) 169-172 1986], in which the structures of ((RO), PSS) 2-head OH, ((RO)zPss), and Zn20H are reported. On the other hand, [Lubricating Oil 25 (2) 95-96゜1980
) also reported the structure of ((R0)2P S S )-Zn40.

As described above, the structure of basic zinc salts has not yet been fully specified, and there are many unknown points.

The present inventors have developed a new dialkyldithiophosphate that does not cause metal corrosion when used as a lubricant or its additive, has excellent thermal stability, and does not precipitate degraded products of metal salts at high temperatures. We conducted extensive research to develop it.

[Failure to solve the problem]

As a result, specific basic zinc salts and neutral zinc salts defined by phosphorus nuclear magnetic resonance (P-NMR) spectra were mixed in a certain ratio, and the alkyl groups contained contained an average of 4.5 carbon atoms. The present invention was completed based on this finding, and it was discovered that the above object can be achieved by dialkyldithiophosphate zinc salt having a primary alkyl group of 6 or more. A dialkyldithiophosphate zinc salt having 6 or more primary alkyl groups, whose composition indicates a peak area ratio of a phosphorus nuclear magnetic resonance (P-NMR) signal of 103.3. 60-85% of basic zinc salts appearing at ~104° lppm.

(b) “P-NMR signal 102.5-103.
The present invention provides a dialkyldithiophosphate zinc salt characterized by comprising 20-0% of a basic zinc salt appearing at 2 ppm and (c) 15-40% of a neutral zinc salt. The present invention also provides a lubricating oil composition characterized by containing a lubricating oil base oil and the above dialkyldithiophosphate zinc salt.

Zinc dialkyldithiophosphate salt (ZnDTP) of the present invention
is a primary alkyl group having an average of 4.6 or more carbon atoms, preferably 4.6 to 18 carbon atoms, particularly preferably 4.6 to 8 carbon atoms (i.e., an alkyl group having a -class carbon atom as a bonding site). ). Here, if the average number of carbon atoms in the alkyl group is less than 4.6, thermal stability is poor and discoloration and precipitation are likely to occur. Further, even secondary alkyl groups and tertiary alkyl groups have poor thermal stability and are prone to discoloration and precipitation.

The above-mentioned -class alkyl group consists of a straight-chain or branched-chain alkyl group, and branched-chain alkyl groups are particularly preferred.

Specific examples of such alkyl groups are n-butanol; isobutanol; n-butanol;
-Pentanol; 2-methyl-1-butanol; 3-methyl-1-butanol: 2゜2-dimethylpropanol; n-hexanol; 2-methyl-1-pentanol:
2-ethyl-I-butanol; 4-methyl-1-pentanol 3-methyl-1-pentanol; n-heptatool, 1,1-diethyl-1-propatool; n-octatool; isooctatool ( (e.g. 2-ethyl-1-hexanol), as well as linear or branched decyl alcohol, dodecyl alcohol, tridecyl alcohol, tetradecyl alcohol, pentadecyl alcohol,
Hexadecyl alcohol, octadecyl alcohol, etc.

The dialkyldithiophosphate zinc salt of the present invention may contain a primary alkyl group as described above, or the primary alkyl group may be one type or a mixture of two or more types. Further, as mentioned above, the average number of carbon atoms in this -class alkyl group is 4.6 or more, but this average number of carbon atoms is
It is calculated as follows. That is, if it contains only 2-ethylhexyl group as an alkyl group, the average number of carbon atoms is naturally 8, or if it contains 70 mol% of isobutyl groups and 30 mol% of 2-ethylhexyl groups, the average number of carbon atoms is 5.2.
It is calculated as follows.

By the way, as mentioned above, the composition of the dialkyldithiophosphate zinc salt of the present invention is such that (a) the peak area ratio of the P-NMR signal is 103.3 to 104.
60-85%, preferably 65-80% of basic zinc salts appearing in lppm.

(b) "P-NMR signal is 102.5-103.
(c) 20-0%, preferably 10-0% of basic zinc salts appearing at 2 ppm; and (c) 15-40%, preferably 20-30% of neutral zinc salts.
Select within the range of %.

In the dialkyldithiophosphate zinc salt of the present invention, if the ratio of each of the zinc salts (a), (b) and (c) above is outside the above range, the thermal stability will be insufficient, which is not preferable. The dialkyldithiophosphate zinc salt of the present invention has each of the zinc salts (a), (b), and (c1) as main components, but may further contain small amounts of other components.

The dialkyldithiophosphate zinc salt of the present invention can be produced by various methods, but generally one or more of the above-mentioned primary alcohols are mixed with niline trisulfide (
Dialkyl dithiophosphoric acid is first produced by reaction with P2Ss). Here, as the niline trisulfide, either a highly reactive product or a slowly reactive product may be used, and a slowly reactive product is preferable because the reaction can be easily controlled. Also, those purified by distillation can be suitably used.

In addition, there is no particular restriction on the ratio of alcohol and niline trisulfide to be used; usually, the alcohol is used in excess of 5 to 20 mol% of the theoretical amount (4 mol) relative to niline trisulfide (1 mol), preferably 5 mol. Select so that there is an excess of about %. The reaction temperature may be normally set appropriately within the range of 40 to 100°C. Note that unreacted niline trisulfide can be removed by filtration or the like.

Further, in the reaction between the alcohol and niline trisulfide, the reaction can be accelerated by using a nitrogen-containing compound such as ε-caprolactam as shown in JP-A-49-87632 as a cocatalyst. Its usage is
There is no particular limit, usually 1% by weight based on niline trisulfide.
or less, preferably about 0.5% by weight. If this promoter is used in excess, it will adversely affect the thermal stability of the dialkyldithiophosphate zinc salt.

In the presence of a promoter such as ε-caprolactam,
By reacting distilled and purified niline trisulfide with the above-mentioned excess amount of alcohol, it is possible to completely react the niline trisulfide, and as a result, the operation of removing unreacted niline trisulfide by filtration is omitted. can.

Next, mineral oil or a solvent as a diluent is added to the dialkyldithiophosphoric acid obtained in this way, if necessary.
By reacting with zinc oxide, the desired dialkyldithiophosphate zinc salt can be produced. It is preferable to use mineral oil because it makes it easier to control the compositional amounts of the basic zinc salts (a) and (b). The amount of mineral oil is between 10 and 30% by weight, preferably around 15% by weight of the dialkyldithiophosphate zinc salt to be produced. Note that water can be added and reacted if necessary.

Further, zinc compounds such as zinc hydroxide and zinc carbonate can be used instead of zinc oxide, but zinc oxide is most preferred. The amount of zinc oxide used is 0.75 mol or more, preferably around 1 mol, per 1 mol of dialkyldithiophosphoric acid.

The amount of water used is 0 to 1 mol, preferably about 0.5 mol, per 1 mol of dialkyldithiophosphoric acid.

The method for producing the dialkyldithiophosphate zinc salt of the present invention described above will be described in more detail as follows. That is, first, 1 mole of niline trisulfide is mixed with about 4 moles of alcohol, and ε-caprolactam (about 0.5% by weight of niline trisulfide is added to
), react at 20-100°C, and keep at this temperature for 1-4 hours until hydrogen sulfide evolution stops.

The mixture is then cooled and any remaining niline trisulfide is removed by filtration.

The reaction in this process proceeds according to the following equation.

4 ROH+P, Ss→2 (RO)2PSSH+H
When using highly reactive niline trisulfide (2S (in the formula, R represents a primary alkyl group)), the niline trisulfide is added to alcohol at 60 to 100°C and maintained for about 2 hours. On the other hand, when using slowly reactive niline pentasulfide, the
The niline trisulfide is added to alcohol and kept for about 1 hour, and then kept at 60 to 100°C for about 2 hours.

Subsequently, mineral oil in an amount of about 15% by weight of zinc dialkyldithiophosphate to be produced and water in an amount of about 0.3 mole (per mole of dialkyldithiophosphoric acid) are added to the obtained dialkyldithiophosphoric acid. Next, add zinc oxide at 30"C or less and keep it for about 1 hour, then at 60-100"C for 1-4 hours.
Keep time. Preferably, it is kept at about 70"C for about 2 hours. Thereafter, unreacted alcohol and water are removed by vacuum distillation, and a liquid product is obtained by adding a filter aid and filtering under pressure.

The reaction in this process proceeds according to the following equation.

2 (R0)zP S S H+ 2 Z n O → Basic zinc salt (a) 10 (b) + ((RO)tPss)t
Zn+H,0 The filter aid is 0.1 to 5% by weight, preferably 0.5 to 3% by weight based on the dialkyldithiophosphate zinc salt.
Add in weight% range. Examples of the filter aid include diatomaceous earth, supercell, and filter cell, among which diatomaceous earth is preferred.

During the above filtration, the temperature of pressure filtration is 20 to 100°C1
Preferably 70″C and pressure 1-10kg/cd
, preferably 3 to 5 kg/cffl.

The ratio of basic zinc salts (a) and (b) in the zinc dialkyldithiophosphate to be produced can be adjusted by changing the temperature at which zinc oxide is added to the dialkyldithiophosphoric acid and the ratio thereof.

The dialkyldithiophosphate zinc salt of the present invention obtained by the method described above can be added to a lubricating oil base oil to form a lubricating oil composition. The amount of dialkyldithiophosphate zinc salt added in this lubricating oil composition is not particularly limited and may be appropriately selected depending on various situations, but is usually 0.001.
-5% by weight, preferably 0.05-1% by weight (especially when used as an engine lubricating oil).

The lubricant base oil in the above-mentioned lubricant composition may include various oils, including mineral oil and vegetable oil.

Either animal oil, synthetic oil, or a mixture thereof may be used. Furthermore, the uses of this lubricating oil composition are various, including automobile and truck engines;
These include crankcase lubricants for spark ignition and compression ignition internal combustion engines such as cycle engines, aircraft piston engines, marine and railroad engines, and the like. It can also be used as a lubricant for gas engines, metering engines, turbines, etc. Additionally, it can be used in transmission bearing lubricants, gear lubricants, metalworking lubricants and other lubricating oil and grease compositions, as well as functional fluids such as pressure fluids and automatic transmission fluids.

Examples of mineral oil-based lubricating base oils include base oils obtained by solvent treatment or acid treatment of liquid petroleum or paraffinic, naphthenic, or mixed paraffinic-naphthenic mineral oils. Oils of lubricating viscosity derived from coal or shale also make useful base oils. Synthetic lubricant base oils include polymerized olefins (for example, polybutylenes, polypropylenes).

propylene-isobutylene copolymers, chlorinated polybutylenes, poly(l-hexenes), poly(l-octenes), poly(l-decenes), etc., and mixtures thereof)
and halo-substituted hydrocarbon oils, alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di(2-ethylhexyl)benzenes, etc.), polyphenyls (e.g.,
biphenyls, terphenyls, alkylated polyphenyls, etc.), alkylated diphenyl ethers, alkylated diphenyl sulfides, and derivatives, analogs, and homologs thereof.

Polymers and copolymers of alkylene oxide, as well as derivatives thereof whose terminal hydroxyl groups have been modified by esterification, etherification, etc., are also suitable as synthetic lubricant base oils. Examples of this include oils obtained by polymerizing ethylene oxide and propylene oxide, alkyl and aryl ethers of these polyoxyalkylene polymers (e.g. methyl-polyisopropylene glycol ether with an average molecular weight of 1000,
diphenyl ether of polyethylene glycol with a molecular weight of 0, diethyl ether of polypropylene glycol with a molecular weight of 1000 to 1500), or mono- and polycarboxylic acid esters thereof, such as acetic acid esters, mixed fatty acid esters having 3 to 8 carbon atoms, or tetraethylene glycol C1□ oxo acid diester.

Other examples of synthetic lubricant base oils include dicarboxylic acids such as phthalic acid, succinic acid, alkylsuccinic acids, alkenylsuccinic acids, maleic acid, azelaic acid, speric acid, sebacic acid, fumaric acid.

adipic acid, lyluic acid dimer, malonic acid, alkylmalonic acids, alkenylmalonic acids, etc.) and various alcohols (for example, butyl alcohol).

Hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol.

Examples include esters with diethylene glycol monoether and propylene glycols. Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, dinormalhexyl fumarate, dioctyl sebacate, diisooctyl azelaate, diisodecyl azelate, dioctyl phthalate, and didecyl phthalate. , dieicosyl sebacate, 2-ethylhexyl diester of lyluic acid dimer.

There are complex esters obtained by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylcaproic acid.

Esters useful as synthetic lubricant base oils include those made from monocarboxylic acids having 3 to 12 carbon atoms and polyols, neopentyl glycol, trimethylolpropane, pentaerythritol, and dipentaerythritol. There are polyol ethers such as slit and tripentaerythrit.

Polyalkyl-, polyaryl-, polyalkoxy-1
Alternatively, silicone oils such as polyaryloxy-siloxane oils and silicate oils are also suitable as synthetic lubricant base oils (eg, tetraethyl silicate, tetraisopropyl silicate.

Tetra silicate (2-ethylhexyl), Tetra silicate (2-ethylhexyl)
4-methyl-2-ethylhexyl), tetra(para-tert-butylphenyl) silicate, hexa(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxanes, poly(methylphenyl)siloxanes, etc.).

Other synthetic lubricant base oils include liquid esters of phosphorus-containing acids (eg, tricresyl phosphate, trioctyl phosphate, diethyl ester of decylphosphonic acid, etc.), monopolymerized tetrahydrofuran, and the like.

Unrefined, refined, rerefined oils, natural or synthetic of the types described above, or mixtures of two or more of these, are useful as base oils in the lubricating oil compositions of the present invention. Unrefined oils are those obtained directly from natural or synthetic sources without any refining treatment. For example, sierre oil obtained directly by retorting, petroleum oil obtained directly from distillation or ester oil obtained directly from an esterification process and used without further treatment are unrefined oils. Refined oil is the same as unrefined oil except that it has been subjected to one or more refining processes.

Such purification methods are known or include, for example, solvent extraction, acid or base extraction, filtration percolation, and the like. Re-refined oil is obtained by subjecting previously used refined oil to the same operations used to obtain refined oil. Such rerefined oil is also known as recycled oil, which is
- further processed with methods applied to remove used additives and oil breakdown products;

The lubricating oil composition of the present invention basically consists of the above dialkyldithiophosphate zinc salt and lubricating oil base oil,
Furthermore, various additives can be added as necessary. Such other additives include rust inhibitors, detergent dispersants (metallic detergent dispersants, ashless detergent dispersants), viscosity index improvers, pour point depressants, fluidity improvers, and antioxidants. , extreme pressure agent.

Antifoaming agents, friction modifiers, coloring agents, flavoring agents, demulsifiers, oily agents, and the like can be mentioned.

Here, the rust inhibitors include triaryl or trialkyl phosphates, such as tributyl phosphate, tricresyl phosphate, aryl or alkyl phosphites, alkylphenol sulfides, Pa
5s-terpene addition compounds, further benzotriazole, phenothiazine, bisoctyldithiathiadiazole, phenyl-1-naphthylamine, aliphatic carboxylic acid,
Examples include aliphatic dicarboxylic acids and sulfonates.

Next, examples of metal detergents and dispersants include alkaline earth metal salts of petroleum sulfonic acids, alkaline earth metal salts of alkylbenzene sulfonic acids, alkaline earth metal salts of carbonic acid such as carboxylates, salicylates, and naphthenates. There are basic compounds, and other examples include alkaline earth metal salts of phosphorus sulfide hydrocarbons and sulfurized alkylphenols.

Ashless detergent-dispersants include: (1) alkenylsuccinimides, bisimides, or borides thereof having about 50 or more carbon atoms; (2) carboxylic acids (or derivatives) and nitrogen-containing compounds such as amines, organic hydroxy compounds such as phenols and alcohols, and/or basic inorganic substances [carboxylic acid-based dispersants], ■ Relatively high molecular weight aliphatic or alicyclic compounds A reaction product of a halide and an amine, preferably a polyalkylene amine [amine dispersant]; ■ A reaction product of an alkylphenol having an alkyl group having about 30 or more carbon atoms with an aldehyde (particularly formaldehyde) and an amine (particularly a polyalkylene polyamide). Reaction product [Mannich dispersant], ■ The above carboxylic acid type, amine or Mannich dispersant is mixed with urea, 1,000 urea, carbon disulfide, aldehyde, ketone, carboxylic acid, hydrocarbon-substituted succinic anhydride, nitrile, epoxide. , boron compounds.

Products obtained by treatment with reagents of phosphorus compounds; and polyoxyethylene-substituted acrylate) [polymer dispersant].

Furthermore, viscosity index improvers include acrylic ester polymers, methacrylic ester polymers, or polymers derived from N-vinylpyrrolidone, diethyl methacrylate, or fumaric acid, as well as polyisobutylene and ethylene-propylene copolymers. , styrene-diene hydrogenated copolymers, etc.

Pour point depressants and fluidity improvers include ethylene-vinyl acetate copolymers, alkenyl succinic acid amide compounds, and ethylene-alkyl acrylate polymers, as well as chlorinated paraffin and naphthalene condensates, and chlorinated Examples include condensates of paraffin and phenol, and polyalkyl methacrylates.

Examples of antioxidants include phenolic and amine antioxidants (e.g. hindered phenol, naphthylamine),
Examples include sulfurized olefins.

Examples of extreme pressure agents include sulfur-based extreme pressure agents, phosphorus-based extreme pressure agents, halogen-based extreme pressure agents, and organometallic extreme-pressure agents (for example, lead naphthenate, Mo-dithiocarbamate, M.

-dithiophosphate), etc.

In addition, antifoaming agents include polysiloxanes (e.g. dimethylpolysiloxane), and friction modifiers include:
Carboxylic acids, esters, amines.

Examples include molybdenum compounds and boron compounds.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples. It should be noted that this example shows a specific embodiment of the present invention, and the scope of the present invention is not limited thereby. In Examples and Comparative Examples, the ratio of basic salts and neutral salts was determined by P-NMR.
-NMR measurement conditions and thermal stability test method are as follows.

"P-NMR measurement conditions Measurement solvent: CD (43) Sample concentration: 6wt%/vo1% Measurement temperature: room temperature Pulse radius: 45 degrees Repetition: 5 seconds Integration number = 250 times Observation frequency: 110 MHz Internal standard: Orthophosphoric acid (adjusted) Thermal stability test method 0.5% by weight of a sample (dialkyl dithiophosphate zinc salt) was dissolved in mineral oil to prepare an evaluation sample.

In a glass container containing 4.4 g of this evaluation sample, a piece of Cu, Fe with a diameter of 2 mm and a length of 2 ao polished with No. 150 abrasive was placed.
, an AI metal rod was placed in a dryer with a built-in rotary table, and kept at 150''C for 5 days.

Evaluation was performed based on the color of the evaluation sample (1 point for colorless, 3 points for yellow, 5 points for brown, and 10 points for black) and the presence (x) and absence (○) of precipitation and metal corrosion of the evaluation sample.

Example 1 (Production of zinc dialkyldithiophosphate salt) A 1i!
In a fourth round-bottomed flask, add mixed alcohol (111.9 g of isobutanol, 30 g of 2-methyl-1-pentanol).
．． 0 g, n-hexanol 17.1 g and 2-ethylhexanol 16.4 g), and nitrogen was added to 100 ml.
Bubbled at /min.

111 g of mildly reactive niline pentasulfide purified by distillation over 30 minutes at a temperature of room temperature to 60° C. was charged into the fourth flask over 30 minutes with stirring.

Thereafter, it was held at 60°C for 2 hours, and further held at 75°C for 3 hours. The resulting mixture was cooled to 25°C, and the slight remaining unreacted niline trisulfide was removed. As a result, 266 g of dialkyldithiophosphoric acid was obtained. The alkyl groups in this dialkyldithiophosphoric acid are isobutyl groups in an amount of 72 mol%.

The 2-methyl-1-pentyl group was 14 mol%, the n-hexyl group was 8 mol%, and the 2-ethylhexyl group was 6 mol%, and the average number of carbon atoms was 4.7.

Next, 266 g of the above dialkyldithiophosphoric acid was added to 11 round-bottomed flasks equipped with a stirrer, a thermometer, and a reflux device.
(1 mol), 9 g of water and 43.9 g of mineral oil were charged. At 30°C, 60.8 g (0.75 mol) of zinc oxide was charged over 30 minutes with stirring. Subsequently, it was held at 30°C for 1 hour, and further held at 70°C for 3 hours. Thereafter, produced water and unreacted alcohol were removed by vacuum distillation. Prepare 1g of diatomaceous earth, then 5kg/al
The mixture was filtered under pressure to obtain 285 g of an oily liquid product (dialkyl dithiophosphate zinc salt). The results of P-NMR analysis and thermal stability test of this product are shown in Table 1.

Example 2 and Comparative Examples 1 to 3 The same operations as in Example 1 were performed except that the addition temperature and amount of zinc oxide were changed as shown in Table 1. The results are shown in Table 1.

Example 3 In Example 1, after adding the alcohol used in the production of dialkyldithiophosphoric acid, ε-caprolactam was further added.
56 g was charged. Thereafter, the reaction was carried out in the same manner as in Example 1, and as a result, no unreacted niline trisulfide remained. Therefore, no operation was performed to remove niline trisulfide.

Next, in the production stage of dialkyldithiophosphate zinc salt, instead of charging 60.8 g of zinc oxide at 30°C,
Example 1 except that 81 g of zinc oxide was charged at 25°C.
The same operation was performed. The results are shown in Table 1. Furthermore, the "P-NMR" of the obtained product is shown in FIG.

Comparative Example 4 The same operation as in Example 1 was performed except that the temperature at which zinc oxide was added was 60°C instead of 30°C. The results are shown in Table 1.

Comparative Example 5 The same operation as in Example 1 was performed, except that after charging zinc oxide, it was immediately heated to 70°C and held at 70°C for 3 hours.

The results are shown in Table 1.

Example 4 The same operation as in Example 2 was performed except that water was not added. The results are shown in Table 1.

Example 5 The same operation as in Example 3 was performed except that highly reactive niline trisulfide was used instead of slowly reactive niline pentasulfide. The results are shown in Table 1.

Comparative Example 6 Table 1 shows the evaluation results of a thermal stability test of a commercially available zinc dialkyldithiophosphate salt. Also, this “P-NM”
R is shown in FIG. In addition, the alkyl group in this product is an isobutyl group at 64 mol%.

Pentyl group 24 mol%, 2-ethylhexyl group 2 months
The average carbon number was 4.72.

Comparative Examples 7 to 10 The dialkyldithiophosphate zinc salt produced in Example 3 and the commercially available dialkyldithiophosphate zinc salt were dissolved in n-hexane, and the solution was injected into a silica gel column chromatography for adsorption.
- Mineral oil bones were removed by development and elution with hexane.

Next, it was sequentially desorbed with petroleum ether and toluene,
The solvent was distilled off to obtain each fraction.

Table 2 shows the results of P-NMR analysis and thermal stability test for each fraction.

Example 6 In Example 3, the alcohol is isobutanol 111
．． Example 3 except that 9 g, n-hexanol 47.1 g and 2-ethylhexanol 16.4 g were used.
The same operation was performed. The results are shown in Table 3.

Example 7 In Example 3, the alcohol is isobutanol 132
The same operation as in Example 3 was performed except that the amount of 2-ethylhexanol was changed to 41.0 g and 2-ethylhexanol. 3rd result
Shown in the table.

Example 8 In Example 3, the alcohol is isobutanol 108
．． The same operation as in Example 3 was performed except that 81.9 g of 2-ethylhexanol was used. The results are shown in Table 3.

Moreover, the "P-NMR" of the obtained product is shown in FIG.

Example 9 The same operation as in Example 3 was performed except that the alcohol was changed to 273 g of 2-ethylhexanol. The results are shown in Table 3.

Comparative Example 11 In Example 3, the alcohol was replaced with isobutanol 139
．． The same operation as in Example 3 was performed except that 9 g and 27.3 g of 2-ethylhexanol were used. The results are shown in Table 3.

Comparative Example 12 In Example 3, alcohol was replaced with isopropanol 75
．． The same operation as in Example 3 was performed, except that 6 g and 85.7 g of 4-methyl-2-pentanol were used, and 48.8 g of zinc oxide was used. The results are shown in Table 3.

Examples 10 to 12 and Comparative Example 13 (Performance evaluation of lubricating oil composition containing dialkyldithiophosphate zinc salt) Example 6 was added to mineral oil (ISOVG32 paraffinic base oil).
．． 8. A lubricating oil composition was prepared by blending the dialkyldithiophosphate zinc salt prepared in 9 or the commercially available dialkyldithiophosphate zinc salt and various additives at the concentrations shown in Table 4. Table 4 also shows the desired usable range of the prepared compositions.

Further, the properties and performance results of the above lubricating oil composition (engine oil) are shown in Table 5.

(Left space below) As shown in Table 5, the oxidation stability and panel coking tests revealed that the lubricating oil compositions containing any of the dialkyldithiophosphate zinc salts of Example 6.8.9 were It can be seen that the oxidative stability and thermal stability are superior to lubricating oil compositions containing salt.

In addition, from Falex and Shell four-ball wear tests,
It can be seen that the sample of Example 11 has excellent load-wearing performance compared to those containing commercially available products, and the samples of Examples 10 and 12 show equivalent load-wearing performance.

〔Effect of the invention〕

As described above, the dialkyldithiophosphate zinc salt of the present invention is not corrosive to metals, especially copper, and has excellent thermal stability, and does not precipitate degraded metal salts even at high temperatures. Therefore, the zinc dialkyl dithiophosphate salts of the present invention are suitable for use in lubricants, functional fluids, fuels.

Greases, hydrocarbon compositions, plastics, resins.

It is expected to find effective use in paints and the like or as additives therein.

In addition, the lubricating oil composition containing this dialkyldithiophosphate zinc salt has excellent thermal stability and is not corrosive to metals such as copper, and is suitable for use in engine oil, refrigeration oil, turbine oil, cylinder oil, bearing oil, etc. It is widely used as various lubricating oils such as oil and gear oil.

[Brief explanation of drawings]

Figure 1 is the "P-NMR spectrum" of the commercially available zinc dialkyldithiophosphate salt used in Comparative Example 6, and Figure 2 is the "P-NMR spectrum" of the zinc dialkyldithiophosphate salt obtained in Example 3.
-NMR spectrum, and FIG. 3 is a "P-NMR spectrum" of the dialkyldithiophosphate zinc salt obtained in Example 8.

Claims (2)

[Claims] (1) A dialkyldithiophosphate zinc salt having a primary alkyl group with an average of 4.6 or more carbon atoms, whose composition is expressed by the peak area ratio of the phosphorus nuclear magnetic resonance (^3^1P-NMR) signal (a )^3^1P-NMR signal is 103.3~1
60-85% of basic zinc salt appearing at 04.1 ppm, (b) ^3^1P-NMR signal is 102.5-1
(c) 20-0% of a basic zinc salt appearing at 0.03.2 ppm; and (c) 15-40% of a neutral zinc salt. (2) A lubricating oil composition comprising a lubricating base oil and the dialkyldithiophosphate zinc salt according to claim 1.