Sulfide compound, extreme pressure agent, and lubricating oil composition containing said extreme pressure agent

Abstract

Provided is a sulfide compound capable of functioning as an extreme pressure additive excellent in oxidation stability and stability of frictional abrasion reduction efficacy. Specifically, the sulfide compound comprises at least a fatty acid triglyceride and sulfur as reaction components, and the content percentage of oleic acid in the fatty acid constituting the fatty acid triglyceride is 80 mass% or more.

Description

[Technical Field]

[0001] The present invention relates to a sulfide compound, an extreme pressure agent, and a lubricating oil composition containing the extreme pressure agent. [Background technology]

[0002] Lubricating oils such as gear oils, engine oils, hydraulic oils, cutting oils, plastic processing oils, and foundry oils are used by blending various additives such as extreme pressure agents, oiliness agents, antioxidants, rust inhibitors, corrosion inhibitors, antifoaming agents, and non-ferrous metal corrosion inhibitors with base oils such as mineral oils, greases, and synthetic oils.

[0003] Of the above additives, extreme pressure agents are additives that reduce friction and wear between metals, and various extreme pressure agents have been proposed, such as chlorine-based extreme pressure agents, sulfur-based extreme pressure agents, phosphorus-based extreme pressure agents, and organometallic compound-based extreme pressure agents (e.g., Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-500244 [Patent Document 2] WO2020 / 030189 issue [Patent Document 3] WO2014 / 188948 Summary of the Invention [Problem to be solved by the invention]

[0005] Lubricating oils are generally exposed to high temperatures and high pressures, which causes extreme pressure agents to oxidize and deteriorate, preventing the intended effect from being achieved. Because of these problems, extreme pressure agents, which are additives, are also required to have oxidation stability, but the extreme pressure agents in Patent Documents 1-3 do not meet this required performance. Furthermore, extreme pressure agents are required to stably exert their friction and wear reducing effect under various loads, but the stability of the friction and wear reducing effect of the extreme pressure agents in Patent Documents 1-3 was also insufficient.

[0006] The problem to be solved by the present invention is to provide a sulfide compound which has excellent oxidation stability and excellent stability in the effect of reducing friction and wear between metals, and which can function as, for example, an extreme pressure agent. Another problem to be solved by the present invention is to provide an extreme pressure agent that is excellent in oxidation stability and stability of the friction and wear reducing effect, and a lubricating oil composition containing the extreme pressure agent. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have found that a sulfide compound having at least an oleic acid-rich unsaturated fatty acid and sulfur as reactive components has excellent oxidation stability and friction and wear reducing effect stability, and have completed the present invention.

[0008] That is, the present invention relates to the following sulfide compounds, etc. 1. A sulfide compound having a fatty acid triglyceride and sulfur as at least reacting components, A sulfide compound in which the content of oleic acid in the fatty acids constituting the fatty acid triglyceride is 80 mass % or more. 2. The sulfide compound according to 1, wherein the content of linoleic acid in the fatty acids constituting the fatty acid triglyceride is 5% by mass or less. 3. The sulfide compound according to 1 or 2, wherein the fatty acid triglyceride is algae oil. 4. The sulfide compound according to any one of 1 to 3, wherein the proportion of sulfur in the reaction components is in the range of 5 to 35 mass % based on the total amount of the reaction components. 5. The sulfide compound according to any one of 1 to 4, further comprising an unsaturated fatty acid alkyl ester as the reaction component. 6. The sulfide compound according to 5, wherein the unsaturated fatty acid alkyl ester is contained in an amount of 10 to 300 parts by mass per 100 parts by mass of the fatty acid triglyceride. 7.40℃ kinematic viscosity is 100 to 1,500 mm 2 7. The sulfide compound according to any one of 1 to 6, wherein the sulfide content is in the range of 1 / s. 8. The sulfide compound according to any one of 1 to 7, which is an extreme pressure agent. 9. A lubricating oil composition containing a base oil and the extreme pressure agent according to claim 8. [Effects of the Invention]

[0009] The present invention can provide a sulfide compound that is excellent in oxidation stability and stability of the effect of reducing friction and wear between metals, and that can function as, for example, an extreme pressure agent. The present invention can provide an extreme pressure agent that is excellent in oxidation stability and stability of the friction and wear reducing effect, and a lubricating oil composition containing the extreme pressure agent. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and can be implemented by making appropriate modifications within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources.

[0011] [Sulfide compounds] The sulfide compound of the present invention is a sulfide compound having a fatty acid triglyceride and sulfur as at least reaction components, and the content of oleic acid in the fatty acids constituting the fatty acid triglyceride is 80 mass % or more.

[0012] The sulfide compound of the present invention includes a compound in which fatty acid triglycerides are crosslinked with sulfur, forming a crosslinked structure with sulfur at the carbon-carbon double bond moiety derived from the unsaturated fatty acid that constitutes the fatty acid triglyceride. In the present invention, by using oleic acid, a monounsaturated fatty acid, as 80% by mass or more of the fatty acids constituting the fatty acid triglyceride, sulfur is easily cross-linked, and a sulfide compound having a long fatty chain and few carbon-carbon unsaturated bonds can be obtained, resulting in excellent oxidation stability. Furthermore, by using oleic acid, an unsaturated fatty acid, as 80% by mass or more of the fatty acids, the proportion of saturated fatty acids is relatively small, and the sulfide compound of the present invention has good fluidity and can exhibit a stable friction and wear reducing effect. The reaction components of the sulfide compound will be explained below.

[0013] Fatty acid triglycerides are triesters in which three hydroxy groups of glycerin are esterified with fatty acids, and are preferably esters of glycerin with fatty acids having 4 to 30 carbon atoms. The fatty acids are preferably fatty acids having 8 to 30 carbon atoms, more preferably fatty acids having 8 to 22 carbon atoms. The fatty acids may be either saturated or unsaturated fatty acids, but 80% by mass or more of them is oleic acid.

[0014] In the present invention, the content of oleic acid in the fatty acids constituting the fatty acid triglyceride is 80% by mass or more, preferably 85% by mass or more, more preferably 87% by mass or more, and even more preferably 90% by mass or more. The upper limit of the oleic acid content is not particularly limited, but is, for example, 95% by mass or less, 99% by mass or less, or 100% by mass or less.

[0015] The content of linoleic acid in the fatty acids constituting the fatty acid triglyceride is preferably 8% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less. By setting the content of linoleic acid, which is a divalent unsaturated fatty acid, within the above range, the amount of carbon-carbon unsaturated bonds in the sulfide compound can be reduced, and oxidation stability can be improved. The lower limit of the content of linoleic acid in the unsaturated fatty acids is not particularly limited, but is, for example, 0% by mass or more, 0.1% by mass or more, or 1% by mass or more.

[0016] The contents of various fatty acids that constitute the fatty acid triglycerides, such as oleic acid, linoleic acid, parethmic acid, stearic acid, linolenic acid, lauric acid, behenic acid, montanic acid, butanoic acid, pentanoic acid, hexanoic acid, decanoic acid, myristic acid, eicosenoic acid, erucic acid, stearidonic acid, punicic acid, palmitoleic acid, ricinoleic acid, eicosadienoic acid, docosadienoic acid, eleostearic acid, pinolenic acid, 9,11-octadecadienoic acid, and 9,12-octadecadienoic acid, are confirmed by the method described in the Examples.

[0017] The fatty acid triglyceride is preferably algal oil. Algal oil-derived fatty acid triglycerides are generally fatty acid triglycerides rich in oleic acid, and the algal oil-derived fatty acid triglycerides can easily have an oleic acid content of 80% by mass or more and a linoleic acid content of 8% by mass or less.

[0018] Algae (organisms that perform oxygenic photosynthesis) store lipids within their cells, and as used herein, "algal oil" refers to oil extracted from algae, including eubacteria, unicellular eukaryotic organisms, and multicellular eukaryotic organisms.

[0019] Examples of algae that are true bacteria include species of the genus Spirulina and Arthrospira.

[0020] Examples of eukaryotic unicellular organisms and eukaryotic multicellular organisms include algae of the genus Chlorella, Pseudochlorella, Heterochlorella, Prototheca, Arthrospira, Euglena, Nannochloropsis, Phaeodactylum, Chlamydomonas, Scenedesmus, Ostreococcus, Selenastrum, and the like. rum species, Haematococcus species, Nitzschia species, Dunaliella species, Navicula species, Trebouxia species, Pseudotrebouxia species, Vavicula species, Bracteococcus species, Gomphonema species, Watanabea species, Botryococcus species, Tetraselmis species, Isochrysis species, and the like.

[0021] Algae can be made to produce fatty acid triglycerides with a desired composition by, for example, modifying fatty acid synthesis genes, and the algae referred to in this specification also include genetically modified versions of the above-mentioned algae.

[0022] The fatty acid triglycerides are not limited to those derived from algae oils, but also include fatty acid triglycerides derived from animal oils and vegetable oils, such as lard, beef tallow, fish oil, rapeseed oil, palm oil, canola oil, coconut oil, corn oil, cottonseed oil, olive oil, palm oil, peanut oil, sunflower oil, soybean oil, safflower oil, rice oil, palm oil, sesame oil, linseed oil, and grapeseed oil.

[0023] However, it is difficult to obtain fatty acid triglycerides derived from animal oils and fatty acid triglycerides derived from vegetable oils with an oleic acid content of 80% by mass or more. For example, fatty acid triglycerides derived from lard, an animal oil-derived fatty acid triglyceride, have an oleic acid content of less than 50% by mass and are fatty acid triglycerides with a relatively high saturated fatty acid content. Furthermore, for vegetable oil-derived fatty acid triglycerides, palm oil-derived fatty acid triglycerides have an oleic acid content of less than 50% by mass, and canola oil-derived fatty acid triglycerides also have an oleic acid content of less than 65% by mass.

[0024] The proportion of sulfur in the reaction components is, for example, in the range of 5 to 35 mass%, preferably in the range of 5 to 25 mass%, more preferably in the range of 5 to 20 mass%, and even more preferably in the range of 10 to 17 mass% or in the range of 8 to 15 mass%, based on the total amount of the reaction components.

[0025] The reaction components of the sulfide compound of the present invention may contain sulfur and a fatty acid triglyceride, or may contain components other than sulfur and a fatty acid triglyceride.

[0026] Examples of reaction components other than sulfur and fatty acid triglycerides include alkyl esters of unsaturated fatty acids. By using unsaturated fatty acid alkyl esters as reaction components, the sulfide compound of the present invention contains compounds in which unsaturated fatty acid alkyl esters are crosslinked with sulfur, making it possible to adjust the kinematic viscosity of the resulting sulfide compound.

[0027] The compound in which the unsaturated fatty acid alkyl esters are crosslinked with sulfur is, for example, a compound represented by the following general formula (1).

[0028] [ka] (In the general formula (1), R 11 and R 13 each independently represents an alkylene group having 3 to 29 carbon atoms or a divalent hydrocarbon group having 3 to 29 carbon atoms and one or more carbon-carbon unsaturated bonds, R 12 and R 14 are each independently an alkyl group having 1 to 12 carbon atoms.

[0029] The compound represented by the general formula (1) is R 11 COOR 12 and R 13 COOR 14 The unsaturated fatty acid alkyl esters corresponding to the above are linked together at the carbon-carbon unsaturated bond portion via (poly)sulfide bonds (where x is an integer of 1 to 8, for example).

[0030] In the general formula (1), R 11 and R 13 The alkylene group having 3 to 29 carbon atoms may be a straight chain or a branched chain. R 11 and R 13 The alkylene group having 3 to 29 carbon atoms is preferably an alkylene group having 7 to 21 carbon atoms.

[0031] In the general formula (1), R 11 and R 13 The "divalent hydrocarbon group having 3 to 29 carbon atoms and having one or more carbon-carbon unsaturated bonds" refers to an alkylene group having one or more carbon-carbon unsaturated bonds, such as an alkenylene group, and may be linear or branched. R 11 and R13 The divalent hydrocarbon group having 3 to 29 carbon atoms and one or more carbon-carbon unsaturated bonds is preferably a divalent hydrocarbon group having 7 to 21 carbon atoms and one or more carbon-carbon unsaturated bonds.

[0032] In the general formula (1), R 12 and R 14 The alkyl group has 1 to 12 carbon atoms and may be linear or branched. R 12 and R 14 The alkyl group having 1 to 12 carbon atoms is preferably an alkyl group having 1 to 6 carbon atoms.

[0033] The unsaturated fatty acid alkyl ester may be, for example, an ester of an unsaturated fatty acid having 4 to 30 carbon atoms and an alcohol having 1 to 12 carbon atoms. Here, the unsaturated fatty acid having 4 to 30 carbon atoms is preferably an unsaturated fatty acid having 8 to 22 carbon atoms, and the alcohol having 1 to 12 carbon atoms is preferably an alcohol having 1 to 6 carbon atoms.

[0034] Specific examples of the unsaturated fatty acids having 4 to 30 carbon atoms include oleic acid, linoleic acid, linolenic acid, eicosenoic acid, erucic acid, stearidonic acid, punicic acid, palmitoleic acid, ricinoleic acid, eicosadienoic acid, docosadienoic acid, eleostearic acid, pinolenic acid, 9,11-octadecadienoic acid, and 9,12-octadecadienoic acid.

[0035] The alkyl ester of an unsaturated fatty acid can be prepared by decomposing a fatty acid triglyceride into glycerin and a fatty acid with, for example, sodium hydroxide, and esterifying the resulting fatty acid with an alcohol. The unsaturated fatty acid alkyl ester obtained by esterifying a fatty acid obtained by decomposing a fatty acid triglyceride with an alcohol is preferred in that the raw material can be shared. The fatty acid preferably has an oleic acid content of 80% by mass or more, and a linoleic acid content of 8% by mass or less.

[0036] The amount of alkyl ester of unsaturated fatty acid used is, for example, 10 to 300 parts by mass, preferably 50 to 200 parts by mass, and more preferably 70 to 150 parts by mass, relative to 100 parts by mass of fatty acid triglyceride.

[0037] As a reaction component other than sulfur and fatty acid triglyceride, an unsaturated hydrocarbon can also be used. By using an unsaturated hydrocarbon as a reaction component, the sulfide compound of the present invention contains a compound in which unsaturated hydrocarbons are crosslinked with sulfur, and it becomes possible to adjust the kinematic viscosity of the obtained sulfide compound.

[0038] The compound in which unsaturated hydrocarbons are crosslinked with sulfur is, for example, a compound represented by the following general formula (2).

[0039] [ka] (In the general formula (2), R 21 and R 22 are each independently an alkyl group having 4 to 30 carbon atoms or a hydrocarbon group having 4 to 30 carbon atoms and one or more carbon-carbon unsaturated bonds.

[0040] The compound represented by the general formula (2) is R 21 and R 22 The unsaturated hydrocarbons corresponding to the above are linked at the carbon-carbon unsaturated bond portion via (poly)sulfide bonds (where y is an integer of 1 to 8, for example).

[0041] In the general formula (2), R 21 and R 22 The alkyl group having 4 to 30 carbon atoms may be a straight chain or a branched chain. R 21 and R 22 The alkyl group having 4 to 30 carbon atoms is preferably an alkyl group having 4 to 22 carbon atoms.

[0042] In the general formula (1), R 21 and R22 The "hydrocarbon group having 4 to 30 carbon atoms and one or more carbon-carbon unsaturated bonds" refers to a hydrocarbon group having one or more carbon-carbon unsaturated bonds, such as an alkenyl group, and may be linear or branched. R 21 and R 22 The hydrocarbon group having 4 to 30 carbon atoms and one or more carbon-carbon unsaturated bonds is preferably a hydrocarbon group having 4 to 22 carbon atoms and one or more carbon-carbon unsaturated bonds.

[0043] The unsaturated hydrocarbon may be any unsaturated hydrocarbon having at least one carbon-carbon unsaturated bond, and is preferably an unsaturated hydrocarbon having 4 to 30 carbon atoms, more preferably an unsaturated hydrocarbon having 4 to 22 carbon atoms. Specific examples of unsaturated hydrocarbons include 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methylpentene, 4-methylheptene, 5-methylundecene, 3,6-dimethylhexanedecene, and diisobutylene.

[0044] Unsaturated hydrocarbons can be used that are derived from, for example, mineral oil.

[0045] The amount of unsaturated hydrocarbon used is, for example, 10 to 300 parts by mass, preferably 50 to 200 parts by mass, and more preferably 70 to 150 parts by mass, relative to 100 parts by mass of fatty acid triglyceride.

[0046] Fatty acid glycerides from animal oils, vegetable oils, algae oils, etc. are usually present as triglycerides in which three fatty acids are attached to glycerin, but may also contain fatty acid monoglycerides and fatty acid diglycerides as reactive components within a range that does not impair the effects of the present invention. When fatty acid monoglycerides and / or fatty acid diglycerides are contained as reaction components, the total amount of fatty acid monoglycerides and fatty acid diglycerides may be, for example, 10% by mass or less, 5% by mass or less, or 3% by mass or less of the total amount of reaction components.

[0047] The reaction components of the sulfide compound of the present invention may consist essentially of, for example, sulfur, fatty acid triglycerides, any unsaturated fatty acid alkyl esters, and any unsaturated hydrocarbons. Here, "consist essentially of" means that the total content of sulfur, fatty acid triglycerides, any unsaturated fatty acid alkyl esters, and any unsaturated hydrocarbons is 90% by mass or more, 95% by mass or more, 98% by mass or more, or 100% by mass of the total amount of the reaction components of the sulfide compound of the present invention.

[0048] The kinematic viscosity of the sulfide compound of the present invention at 40°C is, for example, 100 to 1,500 mm 2 s, preferably 100 to 500 mm 2 The kinematic viscosity at 40°C of the sulfide compound is determined by the method described in the examples.

[0049] [Method for producing sulfide compounds] The sulfide compound of the present invention can be produced by a known method, for example, by reacting sulfur, a fatty acid triglyceride, any unsaturated fatty acid alkyl ester, and any unsaturated hydrocarbon in the presence of hydrogen sulfide and a basic catalyst.

[0050] The state of sulfur used in the production of the sulfide compound of the present invention is not particularly limited, and may be in a solid state such as small lumps, flakes, or powder, or in a molten state (liquid). Sulfur is preferably in a molten state in order to facilitate the scale-up of production.

[0051] Examples of the basic catalyst include alkali metal hydroxides (such as sodium hydroxide and potassium hydroxide), aliphatic amine compounds, and aromatic amine compounds. The amount of the basic catalyst used is, for example, 0.05 to 1.0 part by mass per 100 parts by mass of the reaction components.

[0052] The reaction temperature may be set within the range of, for example, 50 to 200° C., and the reaction time may be set within the range of, for example, 1 to 72 hours.

[0053] [Lubricating oil composition] The sulfide compound of the present invention can be suitably used as an extreme pressure agent. Here, an "extreme pressure agent" is an additive that suppresses wear caused by friction between metals, and it is believed that the sulfide compound suppresses wear by adsorbing onto the metal surface and forming a lubricating film (tribofilm). The extreme pressure agent that is the sulfide compound of the present invention (hereinafter may be referred to as the "extreme pressure agent of the present invention") has excellent oxidation stability, and therefore, deterioration due to heat generated by friction between metals is reduced, and the generation of sludge can be suppressed.

[0054] The lubricating oil composition of the present invention contains a lubricating base oil and the extreme pressure agent of the present invention. The lubricating base oil may be any known one, and examples thereof include mineral oils such as distillate oils or refined oils of paraffinic crude oil, intermediate crude oil, and naphthenic crude oil; and synthetic oils such as low-molecular-weight polybutene, low-molecular-weight polypropylene, C α-olefin oligomers, hydrogenated C α-olefin oligomers, polyol esters (fatty acid esters of trimethylolpropane, fatty acid esters of pentaerythritol, etc.), ester compounds (dibasic acid esters, aromatic polycarboxylic acid esters, phosphate esters, etc.), alkyl aromatic compounds (alkylbenzenes, alkylnaphthalenes, etc.), polyglycol oils (polyalkylene glycols, etc.), and silicone oils.

[0055] The lubricating base oil may be selected appropriately depending on the intended use and conditions of use, and the lubricating base oils used may be one type alone or two or more types in combination.

[0056] The content of the extreme pressure agent of the present invention in the lubricating oil composition of the present invention is, for example, 0.01 to 50 parts by mass, preferably 1 to 50 parts by mass, and more preferably 1 to 30 parts by mass, per 100 parts by mass of the lubricating base oil.

[0057] The extreme pressure agents of the present invention may be used singly or in combination of two or more.

[0058] The lubricating oil composition of the present invention may contain a lubricating base oil and the extreme pressure agent of the present invention, and may further contain additives such as oiliness agents, antiwear agents, extreme pressure agents other than the extreme pressure agent of the present invention, rust inhibitors, corrosion inhibitors, antifoaming agents, detergent dispersants, pour point depressants, viscosity index improvers, antioxidants, emulsifiers, demulsifiers, fungicides, friction modifiers, surfactants, etc. Any of these additives may be used which are well known in the art.

[0059] The lubricating oil composition of the present invention can also be used as a grease by further adding a thickener such as a metal soap.

[0060] The uses of the lubricating oil composition of the present invention are not particularly limited, and it can be used, for example, as an automotive lubricating oil used in drive system devices such as internal combustion engines, automatic transmissions, shock absorbers, and power steering, as well as gears; a metal working oil used in metal working such as cutting, grinding, and plastic working; and a hydraulic oil, which is a power transmission fluid used for power transmission, force control, buffering, and other operations in hydraulic systems such as hydraulic equipment and devices. [Example]

[0061] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0062] Example 1: Preparation of sulfide compound (1) A 1-liter autoclave equipped with a heating device, a hydrogen sulfide blowing tube, and a hydrogen sulfide absorption device was charged with 300 g of fatty acid triglyceride (the fatty acids constituting the fatty acid triglyceride were 94 mass% oleic acid and less than 2 mass% linoleic acid), 300 g of methyl ester of the fatty acid triglyceride (obtained by decomposing the fatty acid triglyceride with sodium hydroxide into glycerin and fatty acid, and esterifying the resulting fatty acid with methanol), 52 g of sulfur, and 3.8 g of a mixture of alkylamines having 16 to 22 carbon atoms as a catalyst. After sealing the autoclave, the pressure inside the reaction vessel was reduced to -0.1 MPa or less using a vacuum pump for vacuum degassing. Thereafter, the vessel was heated until the internal temperature reached 100°C. 12 g of hydrogen sulfide gas (purity 99.9 mol%) was added to the vessel at a pressure of 6 kg / cm. 2 After blowing in 1000 kJ for 1 hour and heating to 120°C, 18 g of hydrogen sulfide gas was blown in over 3.5 hours, and the temperature was maintained at 120°C for 5 hours. The temperature was then raised to 150°C and maintained for 4 hours. The mixture was then cooled to 80°C, and the valve connected to the hydrogen sulfide absorption device was opened to return the pressure to atmospheric pressure. Air was blown in through the blowing tube to distill off the remaining hydrogen sulfide. 3.5 g of thiadiazole and 0.5 g of benzotriazole were added to obtain 669 g of sulfide compound (1) (yield 97%, kinematic viscosity at 40°C: 490 mmHg). 2 / s, sulfur content: 11.0% by mass) ) was obtained.

[0063] The fatty acid triglyceride used in the preparation of sulfide compound (1) was algal oil derived from Chlorella (manufactured by Checkerspot), and the proportions of the fatty acid components constituting the fatty acid triglyceride were identified using gas chromatography. Specifically, the algal oil was decomposed into glycerin and fatty acids with sodium hydroxide, the fatty acids were extracted, the extracted fatty acids were methyl-esterified with methanol, and the resulting fatty acid methyl esters were analyzed by gas chromatography to identify the various fatty acids.

[0064] The algal oil is simply "fatty acid triglycerides extracted from algae" and does not substantially contain any other components. Therefore, it is possible to artificially reproduce the fatty acid triglycerides by reacting glycerin with fatty acids in the above-mentioned ratio.

[0065] (Comparative Example 1: Preparation of sulfide compound (1')) The same procedure as in Example 1 was repeated, except that canola oil (triglyceride of oleic acid: 63% by mass, linoleic acid: 19% by mass) was used instead of algal oil, and the methyl ester of unsaturated fatty acid (oleic acid: 82% by mass, linoleic acid: 9% by mass) was used instead of the methyl ester of algal oil. 669 g of sulfide compound (1') (yield: 97%, kinematic viscosity at 40°C: 330 mm 2 / s, sulfur content: 11.5% by mass

[0066] (Comparative Example 2: Preparation of sulfide compound (2')) A 1-liter autoclave equipped with a heating device, a hydrogen sulfide inlet tube, and a hydrogen sulfide absorption device was charged with 300 g of lard (triglyceride of oleic acid: 49% by mass, linoleic acid: 10% by mass), 184 g of unsaturated fatty acid methyl esters (oleic acid 40-50% and linoleic acid 25-35%) from commercially available recovered oil, 48 g of sulfur, and 1 g of a mixture of alkylamines having 16 to 22 carbon atoms as a catalyst. After sealing the autoclave, the pressure inside the reaction vessel was reduced to -0.1 MPa or less using a vacuum pump, followed by vacuum degassing. Thereafter, the vessel was heated until the internal temperature reached 100°C. 7.5 g of hydrogen sulfide gas (purity 99.9 mol%) was added to the vessel at a pressure of 6 kg / cm. 2 After the temperature was raised to 120°C, 11.2 g of hydrogen sulfide gas was blown in over 3.5 hours and the temperature was maintained at 120°C for 5 hours, after which the temperature was raised to 165°C and maintained for 6 hours. Thereafter, the mixture was cooled to 80°C, and the valve connected to the hydrogen sulfide absorption apparatus was opened to return the pressure to normal pressure. Air was blown in through the blowing tube to distill off the remaining hydrogen sulfide. 3.5 g of thiadiazole and 0.4 g of benzotriazole were added to obtain 539 g of sulfide compound (2') (yield 97%, kinematic viscosity at 40°C: 320 mmHg). 2 / s, sulfur content: 11.5% by mass.

[0067] The sulfide compounds produced in the examples and comparative examples were evaluated as follows, and the results are shown in Table 1.

[0068] (Sulfur content) The sulfur content of sulfide compounds was measured in accordance with JIS K2541-7:2023.

[0069] (Kinematic viscosity) The kinematic viscosity of the sulfide compound at 40° C. was measured in accordance with JIS K2283: 2000. The higher the kinematic viscosity, the better the handleability of the sulfide compound.

[0070] (pour point) The pour point of the sulfide compound was measured in accordance with JIS K2269: 1987. The lower the pour point, the more fluidity is maintained even at low temperatures, and the better the handleability of the sulfide compound.

[0071] (oxidation stability) Group II oil (kinematic viscosity at 40°C 90mm 2 The sulfide compounds produced in the Examples and Comparative Examples were added to a lubricating oil composition (aqueous suspension containing 100% sulfide of ...

[0072] The oxidation stability of the sulfide compounds was evaluated in accordance with JIS K-2514:2013. Specifically, the lubricating oil compositions were degraded at 135°C for 96 hours using an ISOT tester equipped with a glass varnish rod. After the test, the presence or absence of sludge adhesion to the varnish rod was visually evaluated according to the following criteria. ○: Almost no sludge was found on the varnish stick. ×: Sludge adhering to the varnish stick is clearly visible

[0073] (Extreme pressure performance) Paraffin oil (kinematic viscosity at 40°C is 9mm 2 The sulfide compounds produced in the Examples and Comparative Examples were added to a lubricating oil composition (aqueous suspension containing 100% sulfide of ...

[0074] The extreme pressure performance of the sulfide compounds was evaluated in terms of welding load and maximum non-seizure load in accordance with ASTM D-2783. Specifically, the extreme pressure performance of the lubricating oil compositions was evaluated under the following conditions. Vertical shaft rotation speed: 1770 rpm Test steel ball: 1 / 2 inch for ball bearings (SUJ2) Measurement time for welding load and maximum non-seizure load: 10 seconds

[0075] (Friction characteristics) The change in the coefficient of friction of the sulfide compounds produced in the examples and comparative examples was evaluated in accordance with ASTM D2596. Specifically, a four-ball tester (TE92 manufactured by Plint Corporation) was used as the test machine, and a SUJ2 carbon steel ball with a diameter of 1 / 2 inch was used as the test ball. While rotating the test ball at 200 rpm, a load ranging from 500 to 3000 N was applied in a stepped manner every 120 seconds, and the maximum torque value during rotation was observed. The friction coefficient was calculated from the obtained torque values ​​using the formula: friction coefficient = maximum torque value (N·cm) / (1.65 x normal load per single ball) (N), and the change in friction coefficient was evaluated according to the following criteria. The higher the load side of the change in the friction coefficient, the more the corrosion wear caused by friction heat can be reduced. ×: A change of μ of 0.07 or more occurs with a load of less than 1,000 N △: A change of μ of 0.07 or more occurs when the load is between 1,000N and 2,000N ○: A change in μ of 0.07 or more occurs at a load of 2,000 N or more but not exceeding 3,000 N

[0076] [Table 1]

[0077] It can be seen that the sulfide compound of Example 1, which uses a fatty acid triglyceride containing 80% or more by mass of oleic acid, is excellent in both oxidation stability and friction characteristics. On the other hand, the sulfide compound of Comparative Example 1, which uses a fatty acid triglyceride containing less than 80% by mass of oleic acid, is significantly inferior in oxidation stability. Furthermore, the sulfide compound of Comparative Example 2 has poor friction characteristics due to the relatively high amount of saturated fatty acids in the fatty acid triglyceride.

Claims

1. A sulfide compound having at least a fatty acid triglyceride, which is algae oil, and sulfur as reaction components, A sulfide compound in which the content of oleic acid in the fatty acids constituting the fatty acid triglyceride is 80% by mass or more and 99% by mass or less.

2. 2. The sulfide compound according to claim 1, wherein the content of linoleic acid in the fatty acids constituting the fatty acid triglyceride is 5% by mass or less.

3. The algal oil is selected from the group consisting of Chlorella species, Pseudochlorella species, Heterochlorella species, Prototheca species, Arthrospira species, Euglena species, Nannochloropsis species, and the like. Ochloropsis species, Phaeodactylum species, Chlamydomonas species, Scenedesmus species, Ostreococcus species, Selenastrum species, Haematococcus species, s species, Nitzschia species, Dunaliella species, Navicula species, Trebouxia species, Pseudotrebouxia species, Vavicula species, Bracteococcus species 3. The sulfide compound according to claim 1 or 2, which is an oil extracted from algae selected from the group consisting of Algae of the genus Gomphonema, Algae of the genus Watanabea, Algae of the genus Botryococcus, Algae of the genus Tetraselmis, and Algae of the genus Isochrysis.

4. 3. The sulfide compound according to claim 1, wherein the proportion of sulfur in the reaction components is in the range of 5 to 35 mass% based on the total amount of the reaction components.

5. 3. The sulfide compound according to claim 1, further comprising an unsaturated fatty acid alkyl ester as the reaction component.

6. 6. The sulfide compound according to claim 5, wherein the unsaturated fatty acid alkyl ester is contained in an amount of 10 to 300 parts by mass per 100 parts by mass of the fatty acid triglyceride.

7. Dynamic viscosity at 40°C: 100 to 1,500 mm ２ The sulfide compound according to claim 1 or 2, wherein the sulfide compound has a molecular weight in the range of 1 / s.

8. 3. The sulfide compound according to claim 1, which is an extreme pressure agent.

9. A lubricating oil composition comprising a base oil and the extreme pressure agent according to claim 8.

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