RU2642064C2 - Lubricating oil composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: lubricating oil composition is provided in the invention, into which a copolymer of certain olefins and alkyl methacrylates is added. The lubricating oil composition comprises (A) 50 to 90 wt % of, at least, one kind of base oil of lubricating oil selected from mineral oils and synthetic oils and (B) 10 to 50 wt % of a copolymer of olefin and alkyl methacrylate having a weight average molecular weight of 1200 to 50,000, the said lubricating oil base oil comprising (C) carboxylic acid ether in an amount of 5 to 15 wt % relative to the total amount of the lubricating oil composition.

EFFECT: excellent anti-seize properties, the formation of a small amount of sediment, and a high viscosity index.

7 cl, 2 tbl, 1 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a lubricating oil composition and, in particular, relates to a lubricating oil composition which has excellent extreme pressure properties, which forms a small amount of sludge and which also has a high viscosity index.

State of the art

As a renewable source of energy, attention is paid to the production of electricity using wind energy. In a wind power plant for generating electricity, the slow rotation of the blades is accelerated by up-gears so that the power generator can rotate using their energy. But there are many gears in the overdrive gearbox, which require gear oil to lubricate (Gekkan Tribology, No. 273, pages 50-51, May 2010).

In particular, the size of wind turbines for generating electricity has increased in recent years, and since it is necessary to convert large "slow" forces into a high speed using an overdrive, the load on the gears in the transmission mechanism has increased, resulting in the need for gear oils for them Greases with greater resistance to welding (extreme pressure properties). Nevertheless, anti-seize agents that are able to resist welding, when mixed with gear oils, tend to precipitate as a result of aging and oxidation, and the precipitate thus formed can cause wear and welding by “biting” into the gears as a foreign substance, and can also ultimately ultimately cause problems clogging filters and blocking oil lines. Therefore, maintenance is important such as carrying out an early oil change until too much sediment is formed.

At the same time, wind farms for generating electricity are often located in remote areas, such as mountainous areas or sea coasts, which makes frequent maintenance difficult. In addition, for maintenance in hard-to-reach areas, high costs are required, so to reduce operating costs there is a need to increase the intervals between maintenance cycles and the intervals between oil changes. Thus, there is a need to improve the oxidation stability of gear oils and to minimize the amount of sludge generated to reduce the cost of protecting and operating gears.

In addition, a wind turbine for generating electricity operates continuously in a wide range of temperature conditions due to fluctuations between day and night and weather conditions, and, similarly, there is a need to use transmission oil with small fluctuations in viscosity due to temperature changes, i.e. having a high viscosity index.

Based on the foregoing, there is a need for an industrial grade lubricating oil that has excellent extreme pressure properties (resistance to welding), which forms a small amount of sludge and which also has a high viscosity index.

A problem to be solved by the present invention is to provide a lubricating oil composition that has excellent anti-seize properties (resistance to welding), which forms a small amount of sludge and which also has a high viscosity index.

Disclosure of invention

As a result of various and repeated studies and studies aimed at reducing the amount of sludge formed in industrial-grade lubricating oil, the inventors approached the present invention, finding that if a copolymer of a specific olefin and alkyl methacrylate is added in a given fixed molecular weight range, the amount of sludge formed decreases, and, in addition, the viscosity index rises.

In most cases, copolymers of olefins and alkyl methacrylates are used in lubricating oil compositions as viscosity index improvers, but nothing is known about reducing the amount of precipitate formed. This invention is an attempt to reduce the amount of sludge by adding a copolymer of olefin and alkyl methacrylate as an active ingredient to a lubricating oil base oil that contains an anti-seize agent.

Accordingly, the present invention provides a lubricating oil composition containing (A) from 50 to 90% of the mass. at least one type of base oil lubricating oil selected from mineral oils and synthetic oils, and (B) from 10 to 50% of the mass. a copolymer of olefin and alkyl methacrylate having a molecular weight of 1200-50000.

In accordance with this invention, a lubricating oil composition is obtained which has excellent anti-seize properties (resistance to welding), which forms a small amount of sludge and which also has a high viscosity index. By reducing the amount of sludge formed during oxidative aging, wear and welding due to the inclusion of foreign matter are slowed down, and the service life of the mechanisms (for example, transmission) is increased. In addition, the fact that the viscosity index is higher means that the characteristics of the low temperature flow are better and the lubricant layer can be maintained at higher temperatures.

Brief Description of the Drawings

In FIG. 1 shows the molecular weight distribution curves for additive A1 and additive A2.

The implementation of the invention

This invention relates to a lubricating oil composition, characterized in that it contains (A) at least one type of base oil of a lubricating oil selected from mineral oils and synthetic oils, and (B) a copolymer of olefin and alkyl methacrylate having a molecular weight within a certain range. The lubricating oil contains components (A) and (B), but in private embodiments, the lubricating oil may contain components (A) and (B) or may essentially consist of components (A) and (B).

Mineral oils and synthetic oils known as highly refined base oils can be used as the base oil of the present lubricating oil composition, and in particular, base oils that are group II, group III and group IV categories can be used individually or as mixtures. base oil API (American Petroleum Institute). For the base oils used herein, the sulfur content is not more than 300 ppm, preferably not more than 200 ppm, more preferably not more than 100 ppm, and most preferably not more than 50 ppm. In addition, the density is 0.8-0.9 g / cm ³ , but preferably 0.8-0.865 g / cm ³ , and more preferably 0.81-0.83 g / cm ³ . The aromatic content (aromatic content in this invention is determined using ndM analysis in accordance with ASTM D3238) is less than 3%, but preferably less than 2%, and more preferably less than 0.1%.

As examples of Group II base oils, paraffin mineral oils obtained by adequate use of a suitable combination of refining processes, such as hydrotreating and dewaxing, as applied to lubricating oil fractions obtained by atmospheric distillation of crude oil, can be mentioned. Group II base oils purified by hydrotreating methods, such as that of the Gulf Company, are characterized by a total sulfur content of less than 10 ppm and aromatic compounds of not more than 5%, which makes them suitable for the present invention. The viscosity of these base oils is not limited in a special way, but the viscosity index (viscosity indices in this invention are determined in accordance with ASTM D2270 and JIS K2283) should be from 80 to 120 and preferably from 100 to 120. Kinematic viscosity at 40 ° C (kinematic viscosities in this invention are determined in accordance with ASTM D445 and JIS K2283) should preferably be from 2 to 680 mm ² / s and even more preferably from 8 to 220 mm ² / s. In addition, the total sulfur content should be less than 300 ppm, preferably less than 200 ppm, and even more preferably less than 10 ppm. The total nitrogen content should be less than 10 ppm and preferably below 1 ppm. In addition, oils with aniline point (aniline points in this invention are defined in accordance with ASTM D611 and JIS K2256) from 80 ° C to 150 ° C and preferably from 100 ° C to 135 ° C should be used.

Suitable base oils of group III and group II + include paraffin mineral oils obtained by a high degree of hydrotreating of the lubricating oil fractions obtained by atmospheric distillation of crude oil, base oils purified by the Isodewaxing method, in which the wax obtained in the process of dewaxing is replaced with isoparaffins and base oils purified by Mobil paraffin isomerization. The viscosity of these base oils is not specifically limited, but the viscosity index should be from 95 to 145 and preferably from 100 to 140. The kinematic viscosity at 40 ° C should preferably be from 2 to 680 mm ² / s and even more preferably from 8 to 220 mm ² / s. In addition, the total sulfur content should be from 0 to 100 ppm, and preferably less than 10 ppm. The total nitrogen content should be less than 10 ppm and preferably below 1 ppm. In addition, oils with an aniline point from 80 ° C to 150 ° C and preferably from 110 ° C to 135 ° C should be used.

The gas-in-liquid (GTL) base oils synthesized by converting natural gas to liquid using the Fischer-Tropsch method have very low sulfur and aromatic compounds compared to mineral base oils obtained from crude refining oil, and have a very high proportion of the paraffin component and, therefore, excellent oxidation resistance, and since they are characterized by extremely low evaporation losses, they are suitable as base oils for the present invention. The viscosity characteristics of GTL base oils are not specifically limited, but typically a viscosity index should be between 130 and 180, and preferably between 140 and 175. In addition, the kinematic viscosity at 40 ° C should be between 2 and 680 mm ² / s and preferably between 5 up to 120 mm ² / s.

Typically, the total sulfur content should also be less than 10 ppm, and the total nitrogen content less than 1 ppm. A commercially available example of such a GTL base oil is Shell XHVI (registered trademark).

Examples of synthetic oils include polyolefins, alkylbenzenes, alkylnaphthalenes, esters, polyoxyalkylene glycols, polyphenyl ethers, dialkyl diphenyl ethers, fluorine-containing compounds (perfluoropolyethers, fluorinated polyolefins) and silicone oils, or mixtures thereof.

The above polyolefins include polymers of various olefins or their hydrides. Any olefin can be used, and as examples ethylene, propylene, butene and α-olefins with five or more carbon atoms can be mentioned. In preparing the polyolefins, either one type of the above olefins may be used individually, or two or more types may be used in combination.

Particularly suitable are polyolefins called polyalphaolefins (PAOs). They are group IV base oils. Polyalphaolefins can also be mixtures of two or more kinds of synthetic oil.

The viscosity of these synthetic oils is not limited in a special way, but the kinematic viscosity at 40 ° C should be from 2 to 680 mm ² / s, but preferably from 20 to 500 mm ² / s and more preferably from 30 to 450 mm ² / s. The kinematic viscosity at 100 ° C of these synthetic base oils should be from 2 to 100 mm ² / s, but preferably from 4 to 70 mm ² / s and more preferably from 6 to 50 mm ² / s. The viscosity index of said synthetic base oils should be from 110 to 170, but preferably from 120 to 160, and more preferably from 130 to 155. The density at 15 ° C. of said synthetic base oils should be from 0.8000 to 0.8600 g / cm ³ but preferably from 0.8100 to 0.8550 g / cm ³ and more preferably from 0.8250 to 0.8550 g / cm ³ . The aniline point of said synthetic base oils should be from 110 ° C to 180 ° C, but preferably from 120 ° C to 170 ° C, and more preferably from 130 ° C to 165 ° C.

The amount of the above base oil for inclusion in the lubricating oil composition of the present invention is not specifically limited, but based on the total amount of the lubricating oil composition, a typical range can be specified as from 50 to 90% by weight, but preferably from 50 to 80% mass., and more preferably from 50 to 70% of the mass. The lower limit of the amount of base oil to be included, based on the total amount of the lubricating oil composition, must be selected from any content of at least 50, 51, 52, 53, 54, 55, 56, 57, 58 or 59 wt.%, And the upper limit the number of included base oil, based on the total amount of the lubricating oil composition, should be selected from any content not more than 67, 68, 69 or 70% of the mass.

In addition to the above, these base oils may also contain carboxylic acid esters. They are discussed below.

As examples of copolymers of olefins and alkyl methacrylates of the present lubricating oil composition, copolymers can be mentioned in which the main constituent monomers are at least one type of olefin containing from 2 to 20 carbon atoms and at least one type of alkyl methacrylate having alkyl groups with 1-20 carbon atoms.

The above olefins include various types of olefin polymers or their hydrides. Any olefin may be used, but ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene octadecene, nonadecene and eicosen can be mentioned as examples. In addition, you can use one type of the above olefins or a combination of two or more types for olefins contained in the constituent monomers.

As specific examples of the above alkyl methacrylates having alkyl groups with 1-20 carbon atoms, can be mentioned:

(1) alkyl methacrylates having alkyl groups of 1-4 carbon atoms: for example, methyl methacrylate, ethyl methacrylate, n- or iso-propyl methacrylate, n-, iso- or sec-butyl methacrylate;

(2) alkyl methacrylates having alkyl groups with 8 to 20 carbon atoms: for example, n-octyl methacrylate, 2-ethylhexyl methacrylate, n-decyl methacrylate, n-isodecyl methacrylate, n-undecyl methacrylate, n-dodecyl methacrylate, 2-methylundecylmethacrylate -methyldodecylmethacrylate, n-tetradecylmethacrylate, 2-methyltridecylmethacrylate, n-pentadecylmethacrylate, 2-methyltetradecylmethacrylate, n-hexadecylmethacrylate and n-octadecylmethacrylate-13-methocrylocobenzoate Mitsubishi Chemical ( Ltd.)] and Dobanol 45 methacrylate [a mixture of C-13 / C-14 oxo alcohols manufactured by Mitsubishi Chemical Company Ltd.];

(3) alkyl methacrylates having alkyl groups with 5-7 carbon atoms: for example, n-pentyl methacrylate and n-hexyl methacrylate.

Of the above monomers (1) ~ (3), monomers belonging to (1) and (2) are preferred, and monomers (2) are particularly preferred. In addition, preferred monomers (1) from the above in terms of viscosity index are monomers with 1-2 carbon atoms in the alkyl groups. Preferred of the above monomers (2) from the point of view of solubility in the base oil and low temperature characteristics are monomers with 10-20 carbon atoms in the alkyl groups, and more preferred are monomers with 12-14 carbon atoms.

The molecular weight of the above copolymers of olefin and alkyl methacrylate is from 1200 to 80,000, but preferably from 1200 to 50,000, and more preferably from 2,000 to 50,000. The weight average molecular weight is from 5,000 to 30,000, but preferably from 7,000 to 20,000 and more preferably from 9,000 to 16,000 The number average molecular weight is from 2000 to 12000, but preferably from 4000 to 10000 and more preferably from 5000 to 9000. In the case of these molecular weights, the weight average molecular weight (Mw) and number average molecular weight (Mn) are ulyarnymi weights determined by gel permeation chromatography (GPC) and molecular weights, obtained by conversion based on polystyrene as a standard.

The above weight average molecular weight can be controlled by temperature during polymerization, monomer concentration (solvent concentration), amount of catalyst or amount of chain transfer agent.

The molecular weight distribution (Mw / Mn) of the above copolymers of olefins and alkyl methacrylates is from 1 to 2.5, but preferably from 1.3 to 2.2, and particularly preferably from 1.7 to 1.9.

The viscosity of the above copolymers of olefins and alkyl methacrylates is not specifically limited, but the viscosity index should be from 100 to 250, but preferably from 130 to 220, and more preferably from 160 to 200. The kinematic viscosity at 40 ° C of these copolymers should be from 1000 to 12000 mm ² / s, but preferably from 2000 to 10000 mm ² / s, and more preferably from 2500 to 9000 mm ² / s. The kinematic viscosity at 100 ° C of these copolymers should be from 50 to 600 mm ² / s, but preferably from 100 to 500 mm ² / s and more preferably from 150 to 450 mm ² / s. The density at 15 ° C. of these copolymers should be from 0.900 to 0.950 g / cm ³ , but preferably from 0.910 to 0.940 g / cm ³ , and more preferably from 0.925 to 0.935 g / cm ³ .

The copolymers of this invention can be easily obtained by any of the usual methods, and the production method is not limited. For example, they can be obtained by radical polymerization using a diluent, olefins and alkyl methacrylates of selected types and amounts, a copolymerization initiator and a chain transfer agent. They can also be obtained by thermal polymerization of olefins and alkyl methacrylates of selected types and amounts with a diluent. The use of a diluent is optional, but facilitates the regulation of the molecular weight of the copolymer. Thus, it is also often possible to solve problems related to processing, since the copolymers have viscous properties. Any diluent may be used, provided that it is an inert hydrocarbon, but it must be capable of dissolving the copolymer and lubricating oil. As examples of suitable copolymerization initiators, initiators that decompose on heating and form free radicals, for example, peroxide compounds such as benzoyl peroxide, tert-butyl peroctoate and cumene hydroperoxide, and azo compounds such as azobisisobutyronitrile and 2,2'-azobis- ( 2-methylbutannitrile). As examples of suitable chain transfer agents, chain transfer agents that are commonly used in the art can be mentioned, for example, α-styrene dimers, dodecyl mercaptan and ethyl mercaptan. The use of a chain transfer agent is optional, but facilitates the regulation of the molecular weight of the copolymer.

The amount of the above copolymer of olefin and alkyl methacrylate in the lubricating oil composition of the present invention (the amount of the above copolymer of olefin and alkyl methacrylate within the above molecular weight range) is not specifically limited, but based on the total amount of the lubricating oil composition, a typical range can be specified as from 10 to 50 wt. -%, but preferably from 10 to 45 wt. -%, and more preferably from 15 to 40% of the mass. The lower limit of the amount of the copolymer of olefin and alkyl methacrylate, based on the total amount of the lubricating oil composition, should be selected from any content of at least 10, 11, 12, 13, 14 or 15 wt%, and the upper limit of the amount of the copolymer of olefin and alkyl methacrylate, in based on the total amount of the composition of the lubricating oil should be selected from any content of not more than 40, 41, 42, 43, 44, 45, 46, 47, 48, 49 or 50% of the mass. The method for determining the amount of the specified copolymer within a certain range of molecular weight in this case is not limited in a special way, and can be a value theoretically recalculated from the distribution curves of molecular weights. For example, when using additives containing said copolymers as starting material {containing copolymers of olefin and alkyl methacrylate within the above specified range (a suitable range or a particularly suitable range included therein), copolymers of olefin and alkyl methacrylate deviating from the specified specific range and diluents }, molecular weight distribution curves can be obtained by analysis of these additives (see, for example, Fig. 1). A component with a molecular weight from a certain range (for example, from 1200 to 50,000) in the indicated molecular weight distribution curves is defined as “a copolymer of olefin and alkyl methacrylate within the specified specific range,” and the amount of the component within the specified specific range in the total amount of additive is calculated based on these molecular weight distribution curves.

In the case of the present lubricating oil composition, the above lubricating oil base oil may contain carboxylic acid esters.

As examples of carboxylic acid esters, polyol esters can be mentioned. Examples of polyol esters include trihydroxymethylpropyl trioleate (CAS No. 11138-60-6), trimethylolpropane esters (TMP) and carboxylic acids, pentaerythritol (PE) and carboxylic acid esters, dicarboxylic acid esters and trimellitic acid esters. The number of carbon atoms in the residual carboxylic acid groups of the ester molecules should also preferably be from 4 to 20, but more preferably from 6 to 18.

The amount of the aforementioned carboxylic acid ester included in the lubricating oil composition of the present invention is not specifically limited, but based on the total amount of the lubricating oil composition, a typical range can be defined as from 5 to 15% by weight, but preferably from 7 up to 13% of the mass., and more preferably from 8 to 12% of the mass. The amount of carboxylic acid ester included, based on the total amount of the lubricating oil composition, should be selected from any amount from 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15% of the mass.

To further enhance the effectiveness, if necessary, various types of additives other than the above components can be used accordingly. Examples thereof include antioxidants, metal deactivators, extreme pressure agents, lubricity improvers, antifoam agents, viscosity index improvers, pour point reducers, dispersant detergents, anti-corrosion agents, demulsifiers and other lubricant additives known in the art.

Regarding the antioxidants used in this invention, the antioxidants used in lubricating oils are preferred for practical use, and among them amine based antioxidants, sulfur based antioxidants, phenolic based antioxidants and phosphorus based antioxidants can be mentioned. These antioxidants can be used individually or in multiple combinations within the range of 0.01 to 5 parts by mass per 100 parts by mass of base oil.

As examples of the above amine-based antioxidants, dialkyl diphenylamines such as p, p'-dioctyl diphenylamine (Nonflex OD-3 manufactured by Seiko Chemical Ltd), p, p'-di-α-methylbenzyl diphenylamine and N-p-butylphenyl can be mentioned. -N-p'-octylphenylamine, monoalkyl diphenylamines such as mono-tert-butyl diphenylamine and monooctyl diphenylamine, bis (dialkylphenyl) amines such as di (2,4-diethylphenyl) amine and di (2-ethyl-4-nonylphenyl) amine, alkylphenyl-1-naphthylamines, such as octylphenyl-1-naphthylamine and N-tert-dodecylphenyl-1-naphthylamine, 1-naphthylamine, arylnaphthylamines, such as ac phenyl-1-naphthylamine, phenyl-2-naphthylamine, N-hexylphenyl-2-naphthylamine and N-octylphenyl-2-naphthylamine, phenylenediamines such as N, N'-diisopropyl-p-phenylenediamine and N, N'-diphenyl p-phenylenediamine, and phenothiazines such as Phenothiazine (manufactured by Hodogaya Chemical Ltd.) and 3,7-dioctylphenothiazine.

As examples of sulfur-based antioxidants, dialkyl sulfides, such as didodecyl sulfide and dioctadecyl sulfide; thiodipropionic acid esters such as didodecyl thiodipropionate, dioctadecyl thiodipropionate, dimyristyl thiodipropionate and dodecylctadecyl thiodipropionate and 2-mercaptobenzoimidazole.

Phenolic-based antioxidants include 2-tert-butylphenol, 2-tert-butyl-4-methylphenol, 2-tert-butyl-5-methylphenol, 2,4-di-tert-butylphenol, 2,4-dimethyl-6-tert -butylphenol, 2-tert-butyl-4-methoxyphenol, 3-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone (Antage DBH manufactured by Kawaguchi Chemical Industry Co. Ltd.), 2,6- di-tert-butylphenol, 2,6-di-tert-butyl-4-alkylphenols such as 2,6-di-tert-butyl-4-methylphenol and 2,6-di-tert-butyl-4-ethylphenol, and 2,6-di-tert-butyl-4-alkoxyphenols, such as 2,6-di-tert-butyl-4-methoxyphenol and 2,6-di-tert-butyl-4-ethoxyphenol.

In addition, there are 3,5-di-tert-butyl-4-hydroxybenzyl mercaptoctyl acetate, alkyl 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionates, such as n-octadecyl-3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (Yoshinox SS manufactured by Yoshitomi Fine Chemicals Ltd.), n-dodecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 2 ' ethylhexyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, and 3,5-bis (1,1-dimethylethyl) -4 hydroxy-C7 ~ C9 branched esters of benzenepropionic acid (Irganox L135 manufactured by Ciba Specialty Chemicals Ltd.), 2,6-di-tert-butyl-α-dimethylamino-p-cresol, and 2,2'-methylenebis (4-alkyl-6-tert- utyl phenols) such as 2,2'-methylenebis (4-methyl-6-tert-butylphenol) (Antage W-400 manufactured by Kawaguchi Chemical Industry Ltd.) and 2,2'-methylenebis (4-ethyl-6-tert -butylphenol) (Antage W-500 manufactured by Kawaguchi Chemical Industry Ltd).

In addition, there are bisphenols such as 4,4'-butylidenebis (3-methyl-6-tert-butylphenol) (Antage W-300 manufactured by Kawaguchi Chemical Industry Ltd.), 4,4'-methylenebis (2,6- di-tert-butylphenol) (Ionox 220AH manufactured by Shell Japan Ltd.), 4,4'-bis (2,6-di-tert-butylphenol), 2,2- (di-p-hydroxyphenyl) propane (Bisphenol A manufactured by Shell Japan Ltd.), 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 4,4'-cyclohexylidenebis (2,6-tert-butylphenol), hexamethylene glycol bis [3 - (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irganox L109 manufactured by Ciba Specialty Chemicals Ltd.), triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] ( Tominox 917, manufactured by Yoshitomi Fine Chemicals Ltd.), 2,2'-thio- [diethyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox L115, manufactured by Ciba Specialty Chemicals Ltd.) , 3,9-bis {1,1-dimethyl-2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro [5 , 5] -undecane (Sumilizer GA80 manufactured by Sumitomo Chemicals), 4,4'-thiobis (3-methyl-6-tert-butylphenol) (Antage RC manufactured by Kawaguchi Chemical Industry Ltd.) and 2,2'-thiobis ( 4,6-di-tert-butylresorcinol).

In addition, polyphenols such as tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (Irganox L101 manufactured by Ciba Specialty Chemicals Ltd.), 1.1 may also be mentioned. 3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane (Yoshinox 930 manufactured by Yoshitomi Fine Chemicals Ltd.), 1,3,5-trimethyl-2,4,6-tris (3, 5-di-tert-butyl-4-hydroxybenzyl) benzene (Ionox 330 manufactured by Shell Japan Ltd.), bis- [3,3'-bis- (4'-hydroxy-3'-tert-butylphenyl) glycol ester butyric acid], 2- (3 ', 5'-di-tert-butyl-4-hydroxyphenyl), methyl-4- (2ʺ, 4ʺ-di-tert-butyl-3ʺ-hydroxyphenyl) methyl-6-tert-butylphenol and 2,6-bis (2'-hydrox -3'-t-butyl-5'-methylbenzyl) -4-methylphenol, and phenol-aldehyde condensates such as the condensates of p-t-butylphenol and formaldehyde and the condensates of p-t-butylphenol and acetaldehyde.

As examples of phosphorus-based antioxidants, triarylphosphites, such as triphenylphosphite and tricresylphosphite; trialkylphosphites such as trioctadecylphosphite and tridecylphosphite; and tridecyl trithiophosphite.

Metal deactivators that can be used with the composition of the present invention include benzotriazole and benzotriazole derivatives, which are 4-alkylbenzotriazoles, such as 4-methylbenzotriazole and 4-ethylbenzotriazole; 5-alkylbenzotriazoles, such as 5-methylbenzotriazole and 5-ethylbenzotriazole; 1-alkylbenzotriazoles, such as 1-dioctidiaminomethyl-2,3-benzotriazole; and 1-alkyl-tolutriazoles, such as 1-dioctyldiaminomethyl-2,3-tolutriazole; and benzoimidazole and benzoimidazole derivatives, which are 2- (alkyldithio) benzoimidazoles, such as 2- (octyldithio) benzoimidazole and 2- (decyldithio) benzoimidazole, and 2- (dodecyldithio) benzoimidazole; and 2- (alkyldithio) toluimidazoles, such as 2- (octyldithio) toluimidazole, 2- (decyldithio) toluimidazole and 2- (dodecyldithio) toluimidazole.

In addition, indazole, indazole derivatives, which are toluindazoles, such as 4-alkylindazoles and 5-alkylindazoles, benzothiazole and benzothiazole derivatives, which are 2-mercaptobenzothiazole derivatives (Thiolite B-3100 manufactured by Chiyoda Chemical Industries, may be mentioned). ), 2- (alkyldithio) benzothiazoles, such as 2- (hexyldithio) benzothiazole and 2- (octyldithio) benzothiazole, 2- (alkyldithio) tolutiazoles, such as 2- (hexyldithio) tolutiazole and 2- (octyldithio) tolutazol - (N, N-dialkyldithiocarbamyl) benzothiazoles, such as 2- (N, N-diethyldithiocarb mil) benzothiazole, 2- (N, N-dibutyl dithiocarbamyl) benzothiazole and 2- (N, N-dihexyl dithiocarbamyl) benzothiazole, and 2- (N, N-dialkyl dithiocarbamyl) tolutiazoles, such as 2- (N, N-diethyl amide dithiol az , 2- (N, N-dibutyldithiocarbamyl) tolutiazole; and 2- (N, N-dihexyl dithiocarbamyl) tolutiazole.

In addition, benzooxazole derivatives which are 2- (alkyldithio) benzooxazoles, such as 2- (octyldithio) benzooxazole, 2- (decyldithio) benzooxazole and 2- (dodecyl) benzooxazole, or which are 2- (alkyldithio) can be mentioned. ) toluoxazoles, such as 2- (octyldithio) toluoxazole, 2- (decyldithio) toluoxazole and 2- (dodecyldithio) toluoxazole, derivatives of thiadiazole, which are 2,5-bis (alkyldithio) -1,3,4-thiadiazoles, such as 2,5-bis (heptyldithio) -1,3,4-thiadiazole, 2,5-bis (nonyldithio) -1,3,4-thiadiazole, 2,5-bis (dodecyldithio) -1,3,4- tiadia zol and 2,5-bis (octadecyldithio) -1,3,4-thiadiazole, 2,5-bis (N, N-dialkyldithiocarbamyl) -1,3,4-thiadiazoles such as 2,5-bis (N, N-diethyldithiocarbamyl) -1,3,4-thiadiazole, 2,5-bis (N, N-dibutyldithiocarbamyl) -1,3,4-thiadiazole and 2,5-bis (N, N-dioctyldithiocarbamyl) -1,3 , 4-thiadiazole and 2-N, N-dialkyldithiocarbamyl-5-mercapto-1,3,4-thiadiazoles, such as 2-N, N-dibutyldithiocarbamyl-5-mercapto-1,3,4-thiadiazole and 2-N , N-dioctyldithiocarbamyl-5-mercapto-1,3,4-thiadiazole, and triazole derivatives, which are, for example, 1-alkyl-2,4-triazoles, such as 1-dioctylaminomethyl-2,4-triazole. These metal deactivators can be used individually or in multiple combinations within the range of 0.01 to 0.5 parts by weight per 100 parts by weight of base oil.

Phosphorus compounds can also be added to the lubricating oil composition of the present invention to impart antiwear and extreme pressure properties. Examples of phosphoric compounds suitable for the present invention include phosphoric esters, phosphoric acid esters, amine salts of phosphoric acid esters, alkaline phosphoric esters, phosphoric esters, phosphorothionates, zinc dithiophosphates, esters of dithiophosphoric acid and alkanols or polyester type alcohols, and their derivatives, phosphorus-containing carboxylic acids and phosphorus-containing carboxylic acid esters. These phosphorus compounds can be used individually or in multiple combinations within the range of 0.01 to 2 parts by mass per 100 parts by mass of base oil.

As examples of the aforementioned phosphoric esters may be mentioned tributyl phosphate, tripentilfosfat, trigeksilfosfat, trigeptilfosfat, trioctyl phosphate, trinonilfosfat, tridetsilfosfat, triundetsilfosfat, tridodetsilfosfat, tritridetsilfosfat, tritetradetsilfosfat, tripentadetsilfosfat, trigeksadetsilfosfat, trigeptadetsilfosfat, trioktadetsilfosfat, trioleilfosfat, triphenyl phosphate, tris (isopropylphenyl) phosphate, triallyl phosphate, tricresyl phosphate, trixylene phenate, cresyldiphenyl phosphate and xylenyl diphenyl phosphate.

As specific examples of the above complex acidic esters of phosphoric acid can be mentioned acidic monobutilfosfat, sour monopentilfosfat, sour monogeksilfosfat, sour monogeptilfosfat, sour monooktilfosfat, sour monononilfosfat, sour monodetsilfosfat, sour monoundetsilfosfat, sour monododetsilfosfat, sour monotridetsilfosfat, sour monotetradetsilfosfat, sour monopentadetsilfosfat, acid monohexadecyl phosphate, acid monoheptadecyl phosphate, acid mono octadecyl phosphate, acid monooleyl phosphate, acid d butylphosphate, dipentilfosfat sour, sour digeksilfosfat, digeptilfosfat acidic, acidic dioctyl phosphate, dinonilfosfat sour, sour didetsilfosfat, diundetsilfosfat sour, sour didodetsilfosfat, ditridetsilfosfat sour, sour ditetradetsilfosfat, dipentadetsilfosfat sour, sour digeksadetsilfosfat, digeptadetsilfosfat sour, sour and acidic dioktadetsilfosfat dioleilfosfat.

As examples of the above amine salts of phosphoric acid esters, salts of methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, heptylamine, octylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dipentylamine, dihexylamine, dipeptamine triethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine and trioctylamine of the previously mentioned acidic esters of phosphoric acid.

As examples of the above-mentioned esters of phosphorous acid can be mentioned dibutyl phosphite, dipentilfosfit, digeksilfosfit, digeptilfosfit, dioktilfosfit, dinonilfosfit, didetsilfosfit, diundetsilfosfit, didedotsilfosfit, dioleilfosfit, diphenyl phosphite, dikrezilfosfit, tributyl phosphite, tripentilfosfit, trigeksilfosfit, trigeptilfosfit, trioktilfosfit, trinonilfosfit, tridecyl, triundecylphosphite, tridecylphosphite, trioleylphosphite, triphenylphosphite and tricresylphosphite.

As examples of the above fosforotionatov may specifically be mentioned tributifosforotionat, tripentilfosforotionat, trigeksilfosforotionat, trigeptilfosforotionat, trioktilfosforotionat, trinonilfosforotionat, tridetsilfosforotionat, triundetsilfosforotionat, tridedotsilfosforotionat, tritridetsilfosforotionat, tritetradetsilfosforotionat, tripentadetsilfosforotionat, trigeksadetsilfosforotionat, trigeptadetsilfosforotionat, trioktadetsilfosforotionat, trioleilfosforotionat, trifenilfosforotionat, trikrezilfosforoti onate, trixylene phenophosphonate, cresyl diphenyl phosphorothionate, xylen diphenyl phosphorothionate, tris (n-propyl phenyl) phosphorothionate, tris (isopropyl phenyl) phosphorothionate, tris (n-butyl phenyl) phenyl (tris-butyl phenyl) trisulfon phosphorothionate. Mixtures may also be used.

As examples of the zinc dithiophosphates mentioned above, zinc dialkyl dithiophosphates, zinc diaryldithiophosphates and zinc arylalkyldithiophosphates can be mentioned. For example, zinc dialkyldithiophosphates can be used in which the primary or secondary alkyl groups have 3 to 22 carbon atoms, or in which the alkylaryl groups are replaced by alkyl groups with 3-18 carbon atoms. As specific examples of the zinc dialkyldithiophosphates may be mentioned dipropilditiofosfat zinc dibutilditiofosfat zinc dipentilditiofosfat zinc digeksilditiofosfat zinc diizopentilditiofosfat zinc dietilgeksilditiofosfat zinc dioktilditiofosfat zinc dinonilditiofosfat zinc didetsilditiofosfat zinc didodetsilditiofosfat zinc dipropilfenilditiofosfat zinc dipentilfenilditiofosfat zinc dipropilmetilfenilditiofosfat zinc dinonilfenilditiofosfat zinc and zinc dodecylphenyl dithiophosphate.

Fatty acid esters of polyhydric alcohols may be included in the lubricating oil composition of this invention in order to increase oiliness. Partial or complete esters of saturated or unsaturated fatty acids with 1 to 24 carbon atoms and polyhydric alcohols such as glycerol, sorbitol, alkylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol and xylitol can be used, and in addition, compounds can also be included other than the above carboxylic acid ester compounds.

Examples of glycerol esters include glycerol monolaurilate, glycerol monostearate, glycerol monopalmitate, glycerol monooleate, glycerol dilaurylate, glycerol distearate, glycerol dipalmitate, glycerol dioleate. Sorbitol monolaurylate, sorbitol monopalmitate, sorbitol monostearate, sorbitol monooleate, sorbitol dilaurylate, sorbitol dipalmitate, sorbitol distearate, sorbitol dioleate, sorbitol tristearate, sorbitol trilaurate, sorbitol trioleate and sorbitol tetraole can be named as sorbitol esters.

Alkylene glycol esters include ethylene glycol monolaurylate, ethylene glycol monostearate, ethylene glycol monooleate, ethylene glycol dilaurylate, ethylene glycol distearate, ethylene glycol dioleate, propylene glycol monolaurylate, propylene glycol monostaureyl, propylene glycol mono-glycol di-glycol di-glycol di-propylene glycol mono-glycol di-ethylene glycol mono-glycol di-propylene glycol. Neopentyl glycol esters include neopentyl glycol monolaurylate, neopentyl glycol monostearate, neopentyl glycol monooleate, neopentyl glycol dilaurylate, neopentyl glycol distearate and neopentyl glycol dioleate.

Trimethylolpropane esters include trimethylolpropane monolaurylate, trimethylolpropane monostearate, trimethylolpropane monooleate, trimethylolpropane dilaurylate, trimethylolpropane distearate, trimethylolpropane dioleate. Pentaerythritol esters include pentaerythritol monostearate, pentaerythritol monooleate, pentaerythritol dilaurylate, pentaerythritol distearate, pentaerythritol dioleate and dipentaerythritol monooleate. Particular esters of polyhydric alcohols with unsaturated fatty acids are preferably used as such fatty acid esters with polyhydric alcohols.

To improve the low temperature flow and viscosity characteristics, pour points and viscosity index improvers can also be added to the lubricating oil composition of the present invention. Examples of viscosity index improvers include non-dispersant viscosity index improvers, such as polymethacrylates and olefin polymers, such as ethylene-propylene copolymers, styrene-diene copolymers, polyisobutylene and polystyrene, and dispersant-type viscosity index improvers that are copolymerized with nitrogen-containing monomers, and they may also include species other than the above copolymers of olefins and alkyl methacrylates. As for the added quantities, they can be used within the range from 0.05 to 20 mass parts per 100 mass parts of base oil.

Polymethacrylate-based polymers can be mentioned as examples of pour point reducers. As for the added quantities, they can be used within the range from 0.01 to 5 mass parts per 100 mass parts of base oil.

Defoamers can be added to the foaming resistance of the present invention lubricating oil composition. Organosilicates such as diethyl silicate and fluorosilicone and non-silicone antifoam agents such as polyalkyl acrylates can be mentioned as examples of such defoamers suitable for the present invention. As for the added quantities, they can be used individually or in multiple combinations within the range from 0.0001 to 0.1 mass parts per 100 mass parts of base oil.

As examples of demulsifiers suitable for the present invention, mention may be made of demulsifiers commonly used in the prior art as additives for lubricating oils. As for the added quantities, they can be used within the range from 0.0005 to 0.5 mass parts per 100 mass parts of base oil.

The viscosity of the lubricating oil composition of the present invention is not specifically limited, but the viscosity index should be at least 130, preferably at least 140 and more preferably at least 150. The kinematic viscosity at 40 ° C. of the specified lubricating oil composition should be from 140 to 320 mm ² / s, but preferably from 140 to 200 mm ² / s and more preferably from 140 to 160 mm ² / s. The amount of sediment in the Dry TOST test (in an anhydrous turbine oil stability test) of the specified lubricating oil composition should be no more than 1500 mg / kg, but preferably not more than 1300 mg / kg and more preferably not more than 1200 mg / kg. The percentage of residue in the RPVOT test (oxidation test in a rotating pressure vessel) on the fresh oil of the specified lubricating oil composition and the test oil after the Dry TOST test should be at least 40%, but preferably at least 50% and more preferably at least 60%.

The lubricating oil composition of this invention is used as engine oil, hydraulic oil, turbine oil, compressor oil, gear oil, sliding surface oil, bearing oil, or calibration oil. The lubricating oil composition of this invention is ideally suited as a long-term transmission oil. In the present invention, “continuous use transmission oil” is understood to mean an industrial grade transmission oil with large intervals between lubricant oil changes. The intervals between lubricant oil changes are not specifically limited, but typical examples are at least one year and preferably at least 2 years, or more preferably at least 3 years. In particular, the lubricating oil composition of the present invention is ideally suited for overdrive gears in a wind turbine for generating electricity.

Examples

A more detailed explanation of the lubricating oil composition of the present invention, which has excellent anti-seize properties (resistance to welding), which forms a small amount of sludge and which also has a high viscosity index, is given below by way of example embodiments and comparative examples, but the invention is in no way limited given examples.

The following constituent materials were used to obtain examples of an embodiment and comparative examples.

1. Base oils

Polyalphaolefin (PAO) synthetic oils belonging to group IV of the API base oil category (American Petroleum Institute).

(1-1) Base oil 1: Polyalphaolefin (traditional name: PAO6, Characteristics: Kinematic viscosity at 40 ° C: 35.4 mm ² / s; Kinematic viscosity at 100 ° C: 6.44 mm ² / s; Viscosity index 136; density at 15 ° C: 0.8291 g / cm ³ ; aniline point: 130 ° C)

(1-2) Base oil 2: Polyalphaolefin (traditional name: PAO40, characteristics: kinematic viscosity at 40 ° C: 401 mm ² / s; kinematic viscosity at 100 ° C: 40.3 mm ² / s; viscosity index 151; density at 15 ° C: 0.8491 g / cm ³ ; aniline point: 161 ° C)

2. Additives

(2-1) Additive A1: A copolymer of olefin and alkyl methacrylate (traditional name: Viscobase 11-570 manufactured by Evonik Ltd.)

- Molecular mass: 1200-25000 (Fig. 1)

- Number average molecular weight: 5400

- Weight average molecular weight: 9400

- Molecular mass distribution: 1.7

- Kinematic viscosity at 40 ° C: 2500 mm ² / s

- Kinematic viscosity at 100 ° C: 150 mm ² / s

- Viscosity Index: 160

- Density at 15 ° C: 0.926 g / cm ³

(2-2) Additive A2: A copolymer of olefin and alkyl methacrylate (traditional name: Viscobase 11-574 manufactured by Evonik Ltd.)

- Molecular mass: 1200-50000 (Fig. 1)

- Number average molecular weight: 8000

- Weight average molecular weight: 15,000

- Molecular Weight Distribution: 1.9

- Kinematic viscosity at 40 ° C: 9000 mm ² / s

- Kinematic viscosity at 100 ° C: 450 mm ² / s

- Viscosity Index: 200

- Density at 15 ° C: 0.934 g / cm ³

(2-3) Additive A3: Olefin copolymer (traditional name: Lucant HC-1100 manufactured by Mitsui Chemicals Ltd.)

- Number average molecular weight: 6000

- Kinematic viscosity at 40 ° C: 18900 mm ² / s

- Kinematic viscosity at 100 ° C: 1100 mm ² / s

- Viscosity Index: 270

- Density at 15 ° C: 0.850 g / cm ³

(2-4) Additive A4: Polyisoolefin (traditional name: Nisseki Polybutene HV300, manufactured by JX Nippon Oil & Energy Corp.)

- Number average molecular weight: 1400

- Kinematic viscosity at 40 ° C: 26000 mm ² / s

- Kinematic viscosity at 100 ° C: 590 mm ² / s

- Viscosity Index: 155

- Density at 15 ° C: 0.898 g / cm ³

(2-5) Additive B: Transmission oil additive package (traditional name: Anglamo 199, manufactured by Lubrizol Corp.)

- Kinematic viscosity at 40 ° C: 68 mm ² / s

- Kinematic viscosity at 100 ° C: 8.2 mm ² / s

- Density at 15 ° C: 1.07 g / cm ³

- Sulfur content: 29.8-33.8% of the mass.

- Phosphorus content: 1.55-1.89% of the mass.

- Nitrogen content: 0.85-1.03% of the mass.

Additive B: Anglamo is a well-known transmission oil additive package, and the Lubrizol catalog states that if 3.25-3.9% of this package is mixed with lubricating oil, it will meet API GL-4 requirements. API GL-4 is divided into six categories, and the proportion of additives increases with increasing numbers, thereby increasing extreme pressure properties. In the examples of the embodiment, the amount of this additive B in the composition was 2.0% to comply with API GL-3 (with extreme pressure properties at least mid-level), but the amount of additive B in the composition was not specifically limited.

(2-6) Additive C: Trihydroxymethylpropyl trioleate (traditional name: Unister H327R manufactured by NOF Corp.)

Lubricating oil compositions of Examples 1-4 and Comparative Examples 1-4 were prepared using the above constituent materials and compositions shown in the tables.

Dry TOST and RPVOT tests, as shown below, were carried out on lubricating oil compositions of Examples 1-4 and Comparative Examples 1-4 to observe their effectiveness. Dry toast

Following the test method for oxidation stability of turbine oils described in JIS K2514, 360 ml of the test oil was poured into a container and, without adding any amount of water or catalyst, was heated for 336 hours by blowing 3 liters of oxygen every hour in a tank with constant temperature of 120 ° C. 24 hours after completion of the test, the test oil was filtered through a membrane filter with a pore diameter of 1 μm and the amount of precipitate obtained was measured.

RPVOT

According to the oxidation resistance test in the rotating bomb method in JIS K2514, 50 g of the test oil was poured into a container, and with the simultaneous presence of 5 ml of distilled water and a copper catalyst, they were placed in a bomb with an excess oxygen pressure of 6.3 kgf / cm ² at room temperature 25 ° C. The bomb was rotated at a speed of 100 rpm inside the tank with a constant temperature of 150 ° C. The pressure inside the bomb was recorded, and the time was measured from reaching the maximum pressure after the bomb was introduced into the tank with a constant temperature until the pressure dropped to 1.75 kgf / cm ² , and this value was taken as the RPVOT value. RPVOT was performed in fresh oil and in test oil (before filtering) after completion of the TOST.

As shown in Table 1 below, examples of Embodiment 1 and 2 using an olefin and alkyl methacrylate copolymer as a viscosity index improver exhibit a high viscosity index of more than 150, and the amount of sediment after the Dry TOST test is less than 1100 mg / kg. In contrast, in comparative example 1, which uses an olefin copolymer, there is a high viscosity index, but a large amount of precipitate. In comparative example 2, which uses polyisobutylene, there is a small amount of sediment, but a low viscosity index.

Table 2 shows the results when adding trihydroxymethylpropyl trioleate (additive C) in examples of embodiment 1 and 2 and comparative examples 1 and 2. Example of embodiment 3 and example of embodiment 4 using an olefin and alkyl methacrylate copolymer as a viscosity index improver showed a significant improvement in the index viscosity and a greater reduction in precipitate than in the example of Embodiment 1 or the example of Embodiment 2 by adding trihydroxymethylpropyl trioleate . This effect due to the addition of trihydroxymethylpropyl trioleate is also apparent from the difference in results between comparative example 3 and comparative example 1, and between comparative example 4 and comparative example 2, but an increased amount is still present in comparison examples of embodiment 3 and 4 in comparative example 3 sediment, and, as can be seen, in comparative example 4, a lower viscosity index is noted.

Regarding the percentage of RPVOT residue, a value of at least 40% is preferred, but a value of at least 50% is more preferred.

Claims (9)

1. The lubricating oil composition containing (A) from 50 to 90 wt.% At least one type of base oil of a lubricating oil selected from mineral oils and synthetic oils, and (B) from 10 to 50 wt.% A copolymer of olefin and alkyl methacrylate having a weight average molecular weight of from 1200 to 50,000, wherein said lubricating oil base oil contains (C) a carboxylic acid ester in an amount of 5 to 15% by weight relative to the total amount of the lubricating oil composition. 2. The lubricating oil composition according to claim 1, wherein the lubricating oil base oil is a polyalphaolefin or GTL oil (based on a gas-to-liquid process). 3. The lubricating oil composition according to claim 1, in which the copolymer has a weight average molecular weight of 7,000 to 20,000. 4. The lubricating oil composition according to claim 2, in which the copolymer has a weight average molecular weight of 7,000 to 20,000. 5. The lubricating oil composition according to any one of paragraphs. 1-4, in which the kinematic viscosity at 40 ° C of the lubricating oil composition is from 140 to 320 mm ² / s, the viscosity index is at least 150, and the amount of sediment in the Dry TOST test does not exceed 1200 mg / kg. 6. The use of a lubricating oil composition according to any one of paragraphs. 1-5 as engine oil, hydraulic oil, turbine oil, compressor oil, gear oil, sliding surface oil, bearing oil or calibration oil. 7. The use of a lubricating oil composition according to any one of paragraphs. 1-5 as transmission oil for extended use.

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