JP2000044978A - Lubricating oil composition for rotary gas compressor - Google Patents

Abstract

(57) [Summary] [Problem] The mist separation capacity is 0.02 for the stray mist.
g / Nm ³ , when used in a rotary gas compressor having an extremely excellent mist separation capacity,
Provided is a lubricating oil composition for a rotary gas compressor that does not cause trouble due to filter clogging by sludge. A rotary gas containing, as an essential component, one or more compounds selected from (a) a metal-based detergent, (b) an ashless dispersant, and (c) a dispersion-type viscosity index improver. A lubricating oil composition for a compressor is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating oil composition for a rotary gas compressor BACKGROUND OF THE INVENTION, details used for rotating the gas compressor having a mist system mist separation capacity is less than Sutoremisuto weight 0.02 g / Nm ³ Lubricating oil composition to be used.

[0002]

2. Description of the Related Art Rotation of a vane type, a screw type, a scroll type, etc. for compressing gaseous substances such as air, nitrogen gas, oxygen gas, ammonia gas, carbon dioxide gas, hydrocarbon gas, combustion exhaust gas, combustion gas, etc. Development of lubricating oil used in compressors has been focused on improving oxidation stability and reducing sludge generation.

[0003] Therefore, conventional lubricating oils for rotary gas compressors are mainly those in which antioxidants such as hindered phenols and aromatic amines are blended with base oils such as highly refined mineral oils.
Sludge formation due to the lubricating oil itself has been reduced to the utmost by the selection of antioxidants to be used and the combined use of antioxidants.

[0004]

However, in order to further improve the oxidation stability, it is necessary to rely on an increase in the amount of the antioxidant. However, in that case, sludge formation of the antioxidant itself becomes a problem, and a conflicting relationship arises between increasing the amount of the antioxidant and reducing sludge. Therefore, even though it has been considerably improved, this problem has been a significant hindrance in order to further improve the oxidation stability and extend the life of the lubricating oil.

[0005] The sludge caused by the antioxidant in the lubricating oil, together with a sludge precursor (precursor) or sludge itself mixed from the outside, which is not caused by the lubricating oil itself, is generated in the compressed gas flow in the compressor. And may be clogged by the filter. However, the nominal diameter of the finished filter of the filter used in the conventional rotary gas compressor is relatively large, and as a result, the amount of stray mist that cannot be collected by the mist separation system is 0.02 g / Nm ³ or more. When the sludge generation due to the lubricating oil itself was sufficiently reduced, there was almost no fear of filter clogging.

[0006] However, in recent years, the tendency toward cleanliness that dislikes mist in compressed gas has increased, and the fiber density of the filter has tended to increase.
It has been extended from 000 to 6000 hours to 6000 to 12000 hours, and the clogging trouble of the filter in the rotary gas compressor has increased. In such a situation, it was practically impossible to extend the life of the lubricating oil by increasing the amount of the antioxidant, since the amount of sludge would further increase.

The problem of filter clogging due to sludge caused by the antioxidant in the lubricating oil or sludge precursor or sludge mixed from the outside cannot be solved by the conventional lubricating oil for rotary gas compressors.
Development of a new lubricating oil for rotary gas compressors that can solve this problem has been desired.

An object of the present invention is to provide a filter for clogging with sludge even when used in a rotary gas compressor having an extremely excellent mist separation system in which the mist separation capacity is less than 0.02 g / Nm ^3. An object of the present invention is to provide a lubricating oil composition for a rotary gas compressor that does not cause the above trouble.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems of the conventional lubricating oil for rotary gas compressors. It has been found that the above problems can be solved by using a lubricating oil composition containing a specific additive with respect to a synthetic lubricating base oil having a lubricating oil for a rotary gas compressor,
The present invention has been completed.

[0010] The invention according to claim 1 of the present invention is a lubricating oil composition for a rotary gas compressor having a mist separation system having a mist separation capacity of less than 0.02 g / Nm ^{3 in a} mist amount, For a synthetic lubricating base oil having an oxidation stability performance of 50 minutes or more in RBOT value, it is selected from (a) a metal detergent, (b) an ashless dispersant, and (c) a dispersion type viscosity index improver. An object of the present invention is to provide a lubricating oil composition for a rotary gas compressor, comprising one or more compounds as essential components.

According to a second aspect of the present invention, there is provided a lubricating oil composition for a rotary gas compressor having a mist separation system having a mist separation capacity of less than 0.02 g / Nm ^{3 in a} mist amount. , A synthetic lubricating base oil having an oxidation stability of 50 minutes or more in RBOT value (A)
One or more compounds selected from (a) a metal-based detergent and (b) an ashless dispersant; and (B) (c)
An object of the present invention is to provide a lubricating oil composition for a rotary gas compressor, which comprises one or more compounds selected from dispersion viscosity index improvers as essential components.

According to a third aspect of the present invention, there is provided the lubricating oil composition for a rotary gas compressor according to the first or second aspect, wherein the synthetic lubricating base oil comprises (a) alkyl Alkyl naphthalene having at least one group,
(A) an alkylphenyl ether having at least one alkyl group, (c) a silicone oil, and (d) one or more synthetic base materials selected from the group of perfluoroethers. Is what you do.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in more detail. The lubricating base oil in the lubricating oil composition for a rotary gas compressor of the present invention is a synthetic lubricating base oil. However,
It is necessary to use a synthetic lubricating base oil having an RBOT value of 50 minutes or more, preferably 60 minutes or more. When a synthetic lubricating base oil having an RBOT value of less than 50 minutes is used, a large amount of an antioxidant is required to compensate for insufficient oxidative stability, and sludge may increase. . Note that R
The BOT value means a value measured according to "6. Rotating cylinder-type oxidation stability test method" of JIS K2514-1993 "Lubricating oil-oxidation stability test method".

As the synthetic lubricating base oil, R
Any one can be used as long as it satisfies the definition of the BOT value. Specifically, for example, propylene oligomer, polybutene, polyisobutylene, 1-octene oligomer, 1-decene oligomer, ethylene and propylene cooligomer , Poly-α- such as cooligomers of ethylene and 1-octene, and cooligomers of ethylene and 1-decene.
Olefins or hydrides thereof; isoparaffins; alkylbenzenes such as monoalkylbenzene, dialkylbenzene, and polyalkylbenzene; alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene; dioctyl adipate, di-
Dibasic acid esters such as 2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate and ditridecyl glutarate; tribasic acid esters such as trimellitate; trimethylolpropane caprylate; Trimethylolpropaneperargonate, pentaerythritol-
Polyol esters such as 2-ethylhexanoate and pentaerythritol pelargonate; polyethylene glycol, polypropylene glycol, polyoxyethyleneoxypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, polyoxyethyleneoxypropylene glycol monoether, polyethylene glycol Diether, polypropylene glycol diether, polyglycol of polyoxyethylene oxypropylene glycol diether acid; monoalkyl diphenyl ether, dialkyl diphenyl ether, monoalkyl triphenyl ether, dialkyl triphenyl ether, tetraphenyl ether, monoalkyl tetraphenyl ether, dialkyl Tetraphenyl A synthetic base material comprising one or a mixture of two or more selected from phenyl ethers such as ether and pentaphenyl ether; organic phosphates such as tricresyl phosphate; silicone oil; perfluoroether; Those having a value of 50 minutes or more can be used. When a mixture of two or more synthetic base materials is used, it goes without saying that the mixture can be used as the base oil of the present invention if the RBOT value of the mixture is 50 minutes or more.

Among them, (a) alkylnaphthalene having at least one alkyl group, (a) alkylphenyl ether having at least one alkyl group, and (C) Silicone oil (d) It is preferable to use a synthetic substrate composed of one or a mixture of two or more selected from the group of perfluoroethers.

As the (a) alkylnaphthalene having at least one alkyl group, specifically, an alkylnaphthalene having 1 to 24 carbon atoms, preferably 1 to 20 carbon atoms, preferably 1 to 20 carbon atoms, preferably Is an alkylnaphthalene having 1 to 3 alkyl groups.

The alkyl group may be linear or branched, for example, a methyl group, an ethyl group, an n-propyl group,
Isopropyl group, n-butyl group, isobutyl group, sec
-Butyl group, tert-butyl group, linear or branched pentyl group, linear or branched hexyl group, linear or branched heptyl group, linear or branched octyl group, Linear or branched nonyl group, linear or branched decyl group, linear or branched undecyl, linear or branched dodecyl group, linear or branched tridecyl group, linear Linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear or branched heptadecyl group, linear or branched octadecyl group, linear Linear or branched nonadecyl group, linear or branched icosyl group, linear or branched henicosyl group, linear or branched docosyl group,
Examples thereof include a straight-chain or branched tricosyl group and a straight-chain or branched tetracosyl group.

As the alkylnaphthalene, those having at least one linear or branched long-chain alkyl group having 8 to 20 carbon atoms are preferred from the viewpoint of excellent lubricating oil and cooling properties. Mono-long-chain alkylnaphthalene, mono-long-chain alkylmethylnaphthalene, mono-long-chain alkyldimethylnaphthalene having one straight-chain or branched long-chain alkyl group having 8 to 20 carbon atoms; Di-long-chain alkylnaphthalenes having two branched long-chain alkyl groups, di-long-chain alkylmethylnaphthalenes, and mixtures thereof are preferably used.

On the other hand, the (a) alkylphenyl ether having at least one alkyl group specifically has 1 to 24 carbon atoms, preferably 1 carbon atom.
Alkyl phenyl ethers having 1 to 4, preferably 1 to 3 alkyl groups of 20 are exemplified, and as the phenyl ether skeleton, diphenyl ether, triphenyl ether and tetraphenyl ether are preferably used.

The alkyl group may be linear or branched, for example, methyl, ethyl, n-propyl,
Isopropyl group, n-butyl group, isobutyl group, sec
-Butyl group, tert-butyl group, linear or branched pentyl group, linear or branched hexyl group, linear or branched heptyl group, linear or branched octyl group, Linear or branched nonyl group, linear or branched decyl group, linear or branched undecyl, linear or branched dodecyl group, linear or branched tridecyl group, linear Linear or branched tetradecyl group, linear or branched pentadecyl group, linear or branched hexadecyl group, linear or branched heptadecyl group, linear or branched octadecyl group, linear Linear or branched nonadecyl group, linear or branched icosyl group, linear or branched henicosyl group, linear or branched docosyl group,
Examples thereof include a straight-chain or branched tricosyl group and a straight-chain or branched tetracosyl group.

As the alkyl phenyl ether,
From the viewpoint of excellent lubricating properties and cooling properties, those having at least one linear or branched long-chain alkyl group having 8 to 20 carbon atoms are preferable, and particularly, those having 8 to 20 carbon atoms are linear or branched. Mono-long-chain alkyl diphenyl ether, mono-long-chain alkyl triphenyl ether, mono-long-chain alkyl tetraphenyl ether having one long-chain alkyl group;
Di-long-chain alkyl diphenyl ethers, di-long-chain alkyl triphenyl ethers, di-long-chain alkyl tetraphenyl ethers having two straight or branched long-chain alkyl groups having 8 to 20 carbon atoms; and mixtures thereof are preferably used. Can be

On the other hand, as the silicone oil (c) used herein, those having various structures are used. Preferably, one or a mixture of two or more dialkylpolysiloxanes represented by the following general formula (1) is used. Is used.

[0023]

Embedded image

In the general formula (1), R ^{1 to} R ⁴ each independently represent a linear or branched alkyl group having 1 to 4 carbon atoms, and a represents an integer of 2 or more. As R ^{1 to} R ⁴ , specifically, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,
Examples thereof include a sec-butyl group and a tert-butyl group. Among them, a methyl group or an ethyl group is preferable, and a methyl group is more preferable.

On the other hand, as the (d) perfluoroether used herein, those having various structures are used. Preferably, one or more perfluoroethers represented by the following general formula (2) are used. A mixture is used.

[0026]

Embedded image

In the general formula (2), R ⁵ and R ⁶ each independently represent a fluorine atom or a linear or branched perfluoroalkyl group having 1 to 4 carbon atoms, and b is an integer of 2 or more. Is shown. As R ⁵ and R ⁶ , specifically,
Fluorine atom, perfluoromethyl group, perfluoroethyl group, n-perfluoropropyl group, isoperfluoropropyl group, n-perfluorobutyl group, isoperfluorobutyl group, sec-perfluorobutyl group, ter
A t-perfluorobutyl group can be exemplified, and among them, a fluorine atom, a perfluoromethyl group or a perfluoroethyl group is preferable, and a fluorine atom or a perfluoromethyl group is more preferable. As R ⁷ , specifically, a perfluoromethylene group, a perfluoroethylene group, a perfluorotrimethylene group, a perfluoropropylene group,
Perfluorotetramethylene group, perfluorobutylene group, perfluoro-1,2-dimethylethylene group, perfluoro-1-methyltrimethylene group, perfluoro-
Examples thereof include a 2-methyltrimethylene group.

In (d) perfluoroether, an oxyperfluoroalkylene group having a different structure, such as an oxyperfluoromethylene group and an oxyperfluoropropylene group, may be present in one molecule. In that case, the oxyperfluoroalkylene groups having different structures may be randomly copolymerized, alternately copolymerized, or block copolymerized. It is needless to say that these synthetic base oils may be used alone or two or more base oils selected from these may be used in combination at an arbitrary mixing ratio.

Although the viscosity of the synthetic lubricating base oil used in the present invention is optional, it is usually selected from the viewpoints of excellent lubricity, cooling property (heat removal property) and little friction loss due to stirring resistance. The kinematic viscosity at 40 ° C. is preferably 5 to 15
0mm ² / s, more preferably 10~110mm ² / s
It is desirable to use those.

The component (a) in the lubricating oil composition for a rotary gas compressor of the present invention is a metal-based detergent. As the metal-based detergent herein, any compound used as a metal-based detergent for lubricating oils can be used. Specifically, for example, (a-1) an alkaline earth metal sulfonate,
One or two or more metal-based detergents selected from (a-2) alkaline earth metal phenates and (a-3) alkali earth metal salicylates.

(A-1) As the alkaline earth metal sulfonate, more specifically, for example, a molecular weight of 100 to 1
Alkaline earth metal salts of alkyl aromatic sulfonic acids, particularly magnesium salts and / or calcium salts, obtained by sulfonating 500, preferably 200 to 700 alkyl aromatic compounds are preferably used. Specific examples include so-called petroleum sulfonic acid and synthetic sulfonic acid.

As the petroleum sulfonic acid, a sulfonated alkyl aromatic compound of a lubricating oil fraction of a mineral oil, so-called mahoganic acid, which is a by-product of white oil production, is generally used. As the synthetic sulfonic acid, for example, an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant, which is a raw material of a detergent, or obtained by alkylating a polyolefin to benzene, is used as a raw material. A sulfonated version thereof, or a sulfonated version of alkylnaphthalene such as dinonylnaphthalene is used. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but fuming sulfuric acid or sulfuric anhydride is usually used.

(A-2) More specifically, as the alkaline earth metal phenate, for example, at least one linear or branched alkyl group having 4 to 30, preferably 6 to 18 carbon atoms is used. Alkyl phenols having an alkaline earth metal salt of a Mannich reaction product of an alkylphenol obtained by reacting this alkylphenol with elemental sulfur or an alkylphenol obtained by reacting this alkylphenol with formaldehyde,
Particularly, magnesium salts and / or calcium salts are preferably used.

(A-3) More specifically, the alkaline earth metal salicylate has, for example, at least one straight-chain or branched alkyl group having 4 to 30, preferably 6 to 18 carbon atoms. Alkaline earth metal salts of alkyl salicylic acids, particularly magnesium salts and / or calcium salts, are preferably used.

Alkaline earth metal sulfonates, alkaline earth metal phenates and alkaline earth metal salicylates include alkyl aromatic sulfonic acids, alkyl phenols, alkyl phenol sulfides, Mannich reactants of alkyl phenols, alkyl salicylic acids, etc. Reacting with alkaline earth metal bases such as alkaline earth metal oxides and hydroxides of calcium, or once replacing alkali metal salts such as sodium salts and potassium salts with alkaline earth metal salts In addition to the neutral salts (normal salts) obtained by such methods, these neutral salts (normal salts) and excess alkaline earth metal salts or alkaline earth metal bases (hydroxides and oxides of alkaline earth metals) ) By heating in the presence of water It is or basic salts, overbased salts of neutral salt (normal salt) in the presence of carbon dioxide gas obtained by reacting with a base of an alkaline earth metal (overbased salts) are also included.

These reactions are usually carried out in a solvent (such as an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, or a light lubricating base oil). The metal-based detergent is usually commercially available in a diluted state with a light lubricating base oil or the like, and is available. Generally, the metal content is 1.0 to 20% by mass, Preferably, it is used in an amount of 2.0 to 16% by mass.

Although the total base number of the metal detergent used is arbitrary, the total base number is generally 0 to 500 mgKOH / g, preferably 20 to 450 mgKOH / g, since it is excellent in preventing clogging of the filter. Preferably 50-4
It is desirable to use one of 00 mg KOH / g.

The total base number referred to here is Jlsk.
2501 "Petroleum products and lubricants-Neutralization number test method" 7. Means the total base number measured by the perchloric acid method in accordance with

The component (b) in the lubricating oil composition for a rotary gas compressor of the present invention is an ashless dispersant. As the ashless dispersant referred to herein, any compound used as an ashless dispersant for lubricating oils can be used, and specifically, for example, an alkyl group or alkenyl having 40 to 400, preferably 60 to 350 carbon atoms. Examples include a nitrogen-containing compound having at least one group in a molecule or a derivative thereof.

The alkyl group or alkenyl group may be linear or branched, and is preferably derived from an oligomer of olefin such as propylene, 1-butene, isobutylene or a co-oligomer of ethylene and propylene. A branched alkyl group or a branched alkenyl group.

The nitrogen content of the ashless dispersant of the component (b) is also optional, but is usually 0.01 to 10% by mass, preferably 0 to 10% by mass, from the viewpoint of excellent filter clogging prevention properties. 0.1 to 10% by mass is desirably used.

Specific examples of the component (b) include: (b-1) succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in a molecule, or a derivative thereof (b- 2) benzylamine having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof (b-3) at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule Having a polyamine,
Or one or more compounds selected from derivatives thereof.

As the succinimide (b-1), more specifically, for example, a compound represented by the following general formula (3) or (4) can be mentioned.

[0044]

Embedded image

[0045]

Embedded image

In the general formulas (3) and (4), R ⁸ , R ⁹ and R ¹⁰ are each independently a group having 40 to 4 carbon atoms.
Represents an alkyl or alkenyl group of 00, preferably 60 to 350, c represents a number of 1 to 5, preferably 2 to 4, and d represents a number of 0 to 4, preferably 1 to 3, respectively.

The method for producing this succinimide is not limited at all, but for example, propylene oligomer,
Polybutene, a polyolefin such as ethylene-propylene copolymer was reacted with maleic anhydride to obtain alkenyl succinic anhydride, and then imidized using a polyamine such as diethylene triamine, triethylene tetramine, tetraethylene pentamine, and pentaethylene hexane. And the like.

In the succinimide, succinic anhydride was added to one end of the polyamine during imidization.
A so-called mono-type succinimide as in the general formula (3), and succinic anhydride added to both ends of a polyamine;
There is a so-called bis-type succinimide as represented by the general formula (4), but any of them and a mixture thereof can be used as the component (b-1).

(B-2) More specifically, benzylamine includes, for example, compounds represented by the following general formula (5).

[0050]

Embedded image

In the above general formula (5), R ¹¹ has 4 carbon atoms.
Represents an alkyl or alkenyl group of 0 to 400, preferably 60 to 350, and e is 1 to 5, preferably 2 to 4
Are shown respectively.

The method for producing benzylamine is not limited at all. For example, a polyolefin such as propylene oligomer, polybutene or ethylene-propylene copolymer is reacted with phenol to form an alkylphenol, which is then mixed with formaldehyde and diethylenetriamine. And a polyamine such as triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine by reacting the polyamine with a Mannich reaction.

As the polyamine (b-3), more specifically, for example, a compound represented by the following general formula (6) can be mentioned.

[0054]

Embedded image

In the general formula (6), R ¹² has 40 carbon atoms.
Represents an alkyl group or alkenyl group of from 400 to 400, preferably from 60 to 350, and f represents a number of from 1 to 5, preferably from 2 to 4, respectively.

The method for producing this polyamine is not particularly limited. For example, after chlorinating a polyolefin such as propylene oligomer, polybutene or ethylene-propylene copolymer, the chlorinated polyamine is mixed with ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine. And a polyamine such as tetraethylenepentamine and pentaethylenehexamine.

As the component (b) of the present invention, derivatives of these nitrogen-containing compounds are also preferably used. Specific examples of the derivative of the component (b) include, for example, monocarboxylic acids having 2 to 30 carbon atoms (such as fatty acids), oxalic acid, phthalic acid, trimellitic acid, and pyromellitic acid. A so-called acid-modified compound obtained by neutralizing or amidating a part or all of the remaining amino group and / or imino group by reacting a polycarboxylic acid having 2 to 30 carbon atoms; So-called boron-modified compounds in which some or all of the remaining amino groups and / or imino groups have been neutralized; so-called sulfur-modified compounds in which a sulfur compound has acted on these nitrogen-containing compounds; and these nitrogen-containing compounds. A modified compound obtained by combining a compound with two or more kinds of modifications selected from acid modification, boron modification, and sulfur modification; and the like.

The component (c) in the lubricating oil composition for a rotary gas compressor of the present invention is a dispersion type viscosity index improver. As the dispersion-type viscosity index improver referred to here, any compound used as a dispersion-type viscosity index improver for lubricating oil can be used. Specifically, for example, (c-1) the following general formula ( 7) one or two monomers selected from the compounds represented by general formula (8) or general formula (9)

[0059]

Embedded image

[0060]

Embedded image

[0061]

Embedded image

And (c-2) 1 selected from the compounds represented by the following formula (10) or (11):
Kind or two or more kinds of nitrogen-containing monomers

[0063]

Embedded image

[0064]

Embedded image

And a hydride of the copolymer obtained by copolymerizing the copolymer.

In the general formulas (7), (8) and (9), R ¹³ and R ¹⁵ each independently represent a hydrogen atom or a methyl group, and R ¹⁴ represents an alkyl having 1 to 18 carbon atoms. R ¹⁶ represents a hydrocarbon group having 1 to 12 carbon atoms, and X ¹
And X ² are independently a hydrogen atom, a residue of an alkyl alcohol having 1 to 18 carbon atoms (—OR ²⁰ : R ²⁰ is a group having 1 to 18 carbon atoms)
An alkyl group having 18 carbon atoms) or a residue of a monoalkylamine having 1 to 18 carbon atoms (-NHR ²¹ : R ²¹ is a group having 1 to 18 carbon atoms)
18 alkyl groups).

As the alkyl group having 1 to 18 carbon atoms for R ¹⁴ , R ²⁰ and R ²¹ , specifically, for example, methyl, ethyl, n-propyl, isopropyl, n
-Butyl group, isobutyl group, sec-butyl group, ter
a t-butyl group, a linear or branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear or branched nonyl group, Straight or branched decyl group, straight or branched undecyl group, straight or branched undecyl group, straight or branched dodecyl group, straight or branched tridecyl group, straight or branched group A linear or branched pentadecyl group, a linear or branched hexadecyl group, a linear or branched heptadecyl group, a linear or branched octadecyl group, and the like.

As R ¹⁶ , specifically, for example,
Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group,
a tert-butyl group, a linear or branched pentyl group, a linear or branched hexyl group, a linear or branched heptyl group, a linear or branched octyl group, a linear or branched nonyl group, Alkyl groups such as linear or branched decyl, linear or branched undecyl, linear or branched dodecyl, etc .:

Straight or branched butenyl, straight or branched pentenyl, straight or branched hexenyl, straight or branched heptenyl, straight or branched octenyl, straight Or an alkenyl group such as a branched nonenyl group, a linear or branched decenyl group, a linear or branched undecenyl group, a linear or branched dodecenyl group; a carbon atom such as a cyclopentyl group, a cyclohexyl group, or a cycloheptyl group. A cycloalkyl group of the formulas 5 to 7;

A methylcyclopentyl group, a dimethylcyclopentyl group (including all structural isomers), a methylethylcyclopentyl group (including all structural isomers), a diethylcyclopentyl group (including all structural isomers), a methylcyclohexyl group , Dimethylcyclohexyl group (including all structural isomers), methylethylcyclohexyl group (including all structural isomers), diethylcyclohexyl group (including all structural isomers), methylcycloheptyl group, dimethylcycloheptyl group Alkylcycloalkyl groups having 6 to 11 carbon atoms such as (including all structural isomers), methylethylcycloheptyl group (including all structural isomers), and diethylcycloheptyl group (including all structural isomers) ;

Aryl groups such as phenyl group and naphthyl group: tolyl group (including all structural isomers), xylyl group (including all structural isomers), ethylphenyl group (including all structural isomers), Linear or branched propylphenyl group (including all structural isomers), linear or branched butylphenyl group (including all structural isomers), linear or branched pentylphenyl group (including all structural isomers) Alkylaryl groups having 7 to 12 carbon atoms, such as structural isomers), linear or branched hexylphenyl groups (including all structural isomers);

Benzyl, phenylethyl, phenylpropyl (including isomers of propyl), phenylbutyl (including isomers of butyl), phenylpentyl (including isomers of pentyl), An arylalkyl group having 7 to 12 carbon atoms such as a phenylhexyl group (including isomers of a hexyl group);

Specific examples of preferred monomers as the component (c-1) include, for example, C1 to C18 alkyl acrylate, C1 to C18 alkyl methacrylate, C2 to C20 olefin, styrene and methyl. Examples include styrene, maleic anhydride ester, maleic anhydride amide, and mixtures thereof.

On the other hand, the general formulas (10) and (1)
In 1), R ¹⁷ and R ¹⁹ each independently represent a hydrogen atom or a methyl group, R ¹⁸ represents an alkylene group having 2 to ¹⁸ carbon atoms, g represents an integer of 0 or 1, Y ¹ and Y ^{1 Two}
Independently represents an amine residue or a heterocyclic residue containing 1 to 2 nitrogen atoms and 0 to 2 oxygen atoms.

Specific examples of R ¹⁸ include a linear or branched ethylene group, a linear or branched propylene group,
Straight or branched butylene group, straight or branched pentylene group, straight or branched hexylene group, straight or branched heptylene group, straight or branched octylene group, straight or branched A nonylene group, a linear or branched decylene group, a linear or branched undecylene group, a linear or branched dodecylene group, a linear or branched tridecylene group, a linear or branched tetradecylene group, A chain or branched pentadecylene group, a straight or branched hexadecylene group,
Examples thereof include a linear or branched heptadecylene group and a linear or branched octadecylene group.

Specific preferred examples of the nitrogen-containing monomer as the component (c-2) include, for example, dimethylaminomethyl methacrylate, diethylaminomethyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methyl-5-vinyl Examples include pyridine, morpholinomethyl methacrylate, morpholinoethyl methacrylate, N-vinylpyrrolidone, and mixtures thereof. That is, the dispersion type viscosity index improver in the present invention refers to the above (c-
2) A copolymer containing a nitrogen-containing monomer such as the component as a comonomer.

The component (c) of the present invention comprises one or more monomers selected from the components (c-1) and (c-2). Can be obtained by copolymerizing one or more nitrogen-containing monomers selected from the group consisting of: (C-
The molar ratio of component (1) to component (c-2) is arbitrary, but is generally about 80:20 to 95: 5. The reaction method of the copolymerization is also optional, but usually, the component (c-1) and the component (c-) are added in the presence of a polymerization initiator such as benzoyl peroxide.
2) A copolymer can be easily obtained by subjecting the components to radical solution polymerization.

The weight-average molecular weight of the component (c) of the dispersion type viscosity index improver is not limited.
00,000, preferably 5,000-100,000
It is desirable to use those.

As the component (c) of the present invention, the dispersion type polymethacrylate having a weight average molecular weight of from 5,000 to 100,000 and the weight average molecular weight of from 5,000 to 100,000 are particularly preferred from the viewpoint of excellent filter clogging prevention and water separation properties. 5,000-10
A styrene-dispersed styrene-maleic anhydride copolymer having a weight average molecular weight of 5,000 to 100,000
Olefin copolymer having a weight average molecular weight of 5,000
0 to 100,000 dispersed olefin-methacrylate copolymers and mixtures thereof are preferably used.

The lubricating oil composition for a rotary gas compressor of the present invention comprises one or more compounds selected from the above-mentioned components (a), (b) and (c) as essential components. It is characterized by containing.

The content of the components in the lubricating oil composition is arbitrary, but usually the components (a), (b) and (c) are excellent in terms of filter clogging prevention and water separation. )) When two or more compounds selected from the components are used in combination, the total content is preferably 0.001 to 10.0% by mass based on the total amount of the composition.
It is more preferably from 0.01 to 7.0% by mass, and 0.05% by mass.
It is particularly preferable that the content be from 5.0 to 5.0% by mass.

Further, in the present invention, as the lubricating oil composition, one or more compounds selected from (A) (a) a metal detergent and (b) an ashless dispersant, and (B)
(C) A lubricating oil composition for a rotary gas compressor having more excellent filter clogging prevention properties by containing one or more compounds selected from dispersion type viscosity index improvers as essential components. You can get things.

At this time, the content of the component (A) and the component (B) is also optional, but usually, the content of the component (A) (two types selected from the components (a) and (b)) When the above compounds are used in combination, the total content is preferably 0.001 to 10.0% by mass, based on the total amount of the composition, from the viewpoint of excellent filter clogging prevention and water separation properties. The content is more preferably 0.01 to 7.0% by mass, and particularly preferably 0.05 to 5.0% by mass. On the other hand, the content of the component (B) (the total content when two or more compounds selected from the components (c) are used in combination) is excellent in preventing filter clogging and water separation. It is preferably 0.001 to 10.0% by mass, more preferably 0.01 to 7.0% by mass, and more preferably 0.05 to 5.0% by mass, based on the total amount of the composition. Particularly preferred.

Further, in the lubricating oil composition for a rotary gas compressor of the present invention, in order to further enhance its various performances,
Further, known lubricating oil additives, for example, antioxidants, rust inhibitors, corrosion inhibitors, antiwear agents, pour point depressants, defoamers, etc. can be used alone or in a combination of several types. .

As the antioxidant, any one generally used in lubricating oils such as phenolic compounds and amine compounds can be used. Specifically, 2,6-
Alkylphenols such as di-tert-butyl-4-methylphenol; methylene-4,4-bis (2,6
Bis-phenols such as -di-tert-butyl-4-methylphenol); naphthylamines such as phenyl-α-naphthylamine; dialkyldiphenylamines; and zinc dialkyldithiophosphates such as zinc di-2-ethylhexyldithiophosphate.

Examples of the rust inhibitor include aliphatic amines, organic phosphites, organic phosphates, metal organic sulfonates, metal organic phosphates, alkenyl succinates, polyhydric alcohols Esters and the like.

Specific examples of the corrosion inhibitor include benzotriazole, thiadiazole and imidazole compounds.

As the wear inhibitor, for example, a sulfur compound or a phosphorus compound can be used. Specific examples of the sulfur-based compound include disulfides, sulfurized olefins, and sulfurized fats and oils. Specific examples of the phosphorus-based compound include phosphoric acid monoesters, phosphoric diesters, and phosphoric acid. Triesters, phosphite monoesters, phosphite diesters, phosphite triesters,
And salts of these esters with amines and alkanolamines.

Specific examples of the pour point depressant include polymethacrylate polymers compatible with the lubricating base oil used.

As the defoaming agent, specifically, for example, silicones such as dimethyl silicone can be mentioned.

The addition amount of these known additives is optional, but when used, the content thereof is usually 0.01 to 5.0% by mass of the antioxidant based on the total amount of the lubricating oil composition;
For rust inhibitors and corrosion inhibitors, usually 0.01
To 3.0% by mass; usually 0.1 to 5.
0% by mass; usually 0.05 to 5.0% by mass for a pour point depressant; 0.01 to 0.05% by mass for an antifoaming agent;
It is desirable to mix them so that

The lubricating oil composition for a rotary gas compressor of the present invention has a mist separation ability of a stray mist amount of 0.02 g / N.
m ³ is used in a rotary gas compressor having a mist separation system that is less than ³ , as long as the rotary gas compressor satisfies this condition, vane type, screw type, scroll type, etc. It is applicable to the used gas compressor.

Further, the gas to be compressed is not particularly limited, and may be any gas such as air, nitrogen gas, oxygen gas, ammonia gas, carbon dioxide gas, hydrocarbon gas, combustion exhaust gas, combustion gas and the like. Applicable.

The rotary gas compressor having a mist separation system having a mist separation capacity of less than 0.02 g / Nm ³ in the present invention is defined as a discharge gas passing through the mist separation system of the rotary gas compressor. The amount of stray mist measured by the following method is 0.0
A rotary gas compressor that is less than 2 g / Nm ³ is meant.

That is, 1. At the outlet of the rotary gas compressor (the gas outlet after passing through the mist separation system of the compressor), two stray mist collecting filters 5 and 6 shown in FIG. (A stray mist amount measuring device equipped with a micro-eresa / micro-note type filter 1144-2.2.3C-EY as a filter) is connected.
Before bonding, each of the filters 5 and 6 for collecting stremist is put in a desiccator at 50 ° C. for 24 hours, weighed, and its dry weight (g) is measured. Note that the distance indicated by w in FIG. 1 is 1 m or less.

2. The valves 1 and 2 of the stray mist amount measuring device are closed and the valves 3 and 4 are opened so that the discharge gas of the rotary gas compressor passes through the bypass line 9. 3. The discharge gas of the rotary gas compressor is passed through the bypass line 9 continuously for 2 hours or more, and it is confirmed that the discharge gas temperature of the gas flow meter 7 has reached a constant temperature (steady temperature state).
8 is a temperature sensor. 4. After confirming that the discharged gas is in a steady temperature state, open the valves 1 and 2 of the stray mist amount measuring device and close the valves 3 and 4, and discharge the stray mist from the rotary gas compressor for collecting two sets of stray mist. The filters 5 and 6 are allowed to pass continuously for 24 hours. At this time, the total passing gas amount (m ³ ) and the discharge gas temperature (° C.) of the gas flow meter 7 are recorded, and the total passing gas amount (Nm ³ ) in the standard state is obtained. 5. Set the filters 5 and 6 for collecting the stray mist after the test to 5
After being placed in a desiccator at 0 ° C. for 24 hours, it is weighed and the weight (g) after the test is determined. 6. The stray mist amount (g / Nm ³ ) of the rotating gas compressor tested by the following equation is obtained. The recovered oil content (g) is the difference between the total weight (g) of the two stremist collecting filters 5 and 6 after the test and the total weight (g) before the test.

[0097]

The lubricating oil composition for a rotary gas compressor of the present invention does not cause trouble due to filter clogging even when used in a rotary gas compressor having an extremely excellent mist separation ability as described above. It is a major feature in that it exhibits excellent performance.

[0099]

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these contents.

(Examples 1 to 11) With respect to the lubricating oil composition for a rotary gas compressor according to the present invention shown in Table 1, a filter differential pressure monitor test shown below was carried out, and the results are also shown in Table 1.

[Filter differential pressure monitor test] A rotary gas compressor KST6P manufactured by Kobe Steel Co., Ltd. using a lubricating oil composition for a rotary gas compressor (the amount of stray mist measured by the method described above is 0.01 g / Nm ^3). ) Is continuously operated, and the differential pressure (k) before and after the mist filter equipped with the compressor when the operation time elapses 6000 hours and 9000 hours.
Pa) was measured.

(Comparative Examples 1 and 2) For comparison, the same tests as in Examples 1 to 11 were carried out for the case where the component of the present invention was not used, and the results are also shown in Table 1.

[0103]

[Table 1]

As is clear from the results in Table 1, the lubricating oil composition for a rotary gas compressor according to the present invention (Examples 1 to 10)
Compared with the compositions of Comparative Examples 1 and 2, the absolute value of the filter differential pressure in the actual machine test and the rate of increase due to the elapse of the operation time were low, indicating excellent performance in preventing filter clogging. Further, when the component (a) and the component (c) were used together (Example 10) and when the component (b) and the component (c) were used together (Example 11), more excellent prevention of filter clogging was obtained.

[0105]

The lubricating oil composition for a rotary gas compressor according to the present invention has a mist separation ability of a stray mist amount of 0.02 g / N.
Even when used in a rotary gas compressor having an extremely excellent mist separation capability of less than m ^3, it exhibits an excellent performance of not causing trouble due to filter clogging by sludge.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a stray mist amount measuring device.

[Explanation of symbols]

 1, 2, 3, 4 Valve 5, 6 Filter for collecting stremist 7 Gas flow meter 8 Temperature sensor 9 Bypass line

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C10M 107: 54 135: 10 133: 16 133: 04 149: 04) C10N 10:04 40:06

Claims (3)

[Claims] 1. The mist separation ability is equal to a streak mist amount of 0.
(A) a lubricating oil composition for a rotary gas compressor having a mist separation system of less than 02 g / Nm ³ , which has a RBOT value of 50 minutes or more and has oxidation stability performance; Metal-based detergent, (b) ashless dispersant,
(C) A lubricating oil composition for a rotary gas compressor comprising, as an essential component, one or more compounds selected from dispersion-type viscosity index improvers. 2. The mist separation ability is equal to a stray mist amount of 0.
(A) a lubricating oil composition for a rotary gas compressor having a mist separation system of less than 02 g / Nm ³ having a RBOT value of 50 minutes or more and having an oxidation stabilization performance; One or two or more compounds selected from (a) a metal-based detergent and (b) an ashless dispersant, and one or two compounds selected from (B) and (c) a dispersion-type viscosity index improver A lubricating oil composition for a rotary gas compressor, comprising the above compound as an essential component. 3. The synthetic lubricating base oil according to claim 1, wherein (a) an alkylnaphthalene having at least one alkyl group;
(A) an alkylphenyl ether having at least one alkyl group, (c) a silicone oil, and (d) one or more synthetic base materials selected from the group consisting of perfluoroethers. The lubricating oil composition for a rotary gas compressor according to claim 1 or 2, wherein