JP2006335963A - Method for lubricating fluorine-containing composite material containing solid lubricant and lubricating oil composition for the material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil composition which prevents an apparatus having a fluororesin composite material containing a solid lubricant as its sliding part from undergoing wear and solid lubricant elution, more particularly, a lubricating oil composition desirable for use in a shock absorber and to provide a method for lubricating the apparatus. <P>SOLUTION: The lubricating oil composition is one used in an apparatus having sliding parts at least either of which is a solid-lubricant-containing fluororesin composite material, wherein the lubricating oil composition comprises a lubricating base oil, (A) an acidic additive, and (B) a basic additive, and the difference between the total number (a) of moles of (A) and the total number (b) of (B) is within 35% based on either of (a) or (b) used in a larger amount. The method for lubricating the apparatus comprises using the lubricating oil composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for lubricating a device having a sliding portion, at least one of which is a fluororesin-based composite material containing a solid lubricant, and a lubricating oil composition for the device, and more specifically, the composite material mounted on a piston and More particularly, the present invention relates to a lubricating method for a device having a sliding portion composed of a cylinder and a lubricating oil composition for the device, and more particularly to a lubricating method for a shock absorber having the sliding portion and a lubricating oil composition for the shock absorber. .

  Various sliding surfaces of various mechanical devices such as compressors, sliding bearings, hydraulic actuators, etc., or seal parts that enclose lubricating oil or gas, sliding characteristics of the sliding surface in the presence or absence of lubricating oil In order to maintain a good quality, a sliding surface may be coated with a solid lubricating film or a solid lubricant. Various rubber materials and various resin materials, or various resin materials containing self-lubricating molybdenum disulfide and graphite, or other various solid lubricants may be used for the solid lubricant film.

Incidentally, there is a shock absorber as one type of hydraulic actuator. There are various types of shock absorbers, but they basically consist of a piston with a valve and a cylinder (also called an outer cylinder or tube). The piston is fixed to the rod, the valve mounted on the piston slides on the inner surface of the cylinder, and the rod slides on the seal of the rod guide portion. The shock absorber encloses hydraulic oil and gas if necessary, and performs a buffering action by the resistance of the hydraulic oil passing through the valve.
Nitrile rubber, fluorine rubber, or the like is used as a seal material for the shock absorber rod and rod guide portion, and a sliding material called a piston band is attached to the piston. As this piston band, the above-mentioned sealing material or highly durable fluororesin-based material is used. Among them, a solid lubricant having self-lubricating property, for example, a carbon material such as graphite, in order to further impart low friction and durability. A resin material containing may be used.

  However, when a fluororesin-based composite material containing such a solid lubricant is used to give low friction and durability, depending on the composition of the lubricating oil used, the composite material may be worn out or the solid lubricant may be eluted. It has been found that the strength of the composite material itself is reduced, and there is a possibility that problems such as contamination and precipitation of lubricating oil may occur along with damage and peeling. If this composite material is worn, damaged, or peeled off in the shock absorber, not only the sealing performance between the piston and cylinder will be insufficient, but a sufficient damping force will not be generated. There is a risk that seizure may occur and the shock absorber itself may be damaged.

Conventionally, as hydraulic fluids for shock absorbers, friction characteristics, wear prevention properties, durability, and the like of the shock absorbers have been improved by optimizing friction modifiers and antiwear agents (for example, Patent Documents 1 to 6). However, a solution to the problem that occurs when a fluororesin-based composite material containing a solid lubricant as described above is used has not been clarified.
JP 7-224293 A JP-A-7-258678 JP-A-6-128581 JP 2000-192067 A JP 2002-194376 A JP-A-5-255683

  The present invention provides an apparatus having a sliding part, at least one of which is a fluororesin-based composite material containing a solid lubricant, which can suppress elution and precipitation of the solid lubricant and can prevent wear and breakage of the composite material. The present invention provides a method and a lubricating oil composition, and in particular, a lubricating method for a device having a sliding portion composed of the composite material and a cylinder mounted on a piston such as a shock absorber, and a lubricating oil composition for the device. Objective.

  As a result of intensive studies to solve the above problems, the present inventors have used this composite material when the acidic additive or basic additive to be blended in the lubricating oil is used alone or the blend lacks the balance. It has been found that the elution of the solid lubricant in the steel reduces the strength and is one of the causes of accelerated wear and breakage. And it turned out that abrasion and breakage of this composite material can be prevented by mix | blending an acidic additive and a basic additive with the optimal balance.

  That is, the present invention relates to a method for lubricating an apparatus having a sliding portion, at least one of which is a fluororesin-based composite material containing a solid lubricant, and the sliding portion includes a lubricating base oil and (A) an acid addition The difference between the total number of moles (a) of (A) and the total number of moles (b) of (B) (b) On the other hand, the lubricating method is characterized by lubricating with a lubricating oil composition prepared to be within 35%.

  The present invention also relates to a lubricating oil composition used in an apparatus having a sliding part, at least one of which is a fluororesin-based composite material containing a solid lubricant, the lubricating oil composition comprising a lubricating base oil and ( A) an acidic additive and (B) a basic additive, and the difference between the total number of moles (a) of (A) and the total number of moles (b) of (B) is (a) and (b) The lubricating oil composition is characterized by being prepared so as to be within 35% with respect to the larger amount.

The sliding part is preferably a sliding part constituted by the composite material and a cylinder mounted on a piston.
Moreover, the lubricating method and lubricating oil composition of the present invention are particularly suitable when the device is a shock absorber.
The lubricating method and lubricating oil composition of the present invention are particularly suitable when the composite material is a fluororesin composite material containing graphite.
Moreover, it is preferable that the said acidic additive is an additive which shows 1 type, or 2 or more types of acidity chosen from acidic phosphate ester, acidic phosphite, carboxylic acid, and these derivatives.
Moreover, it is preferable that the said basic additive is an additive which shows the 1 type, or 2 or more types of basicity chosen from the compound which has an amino group, an imino group, or an amide group, and these derivatives.

  Hereinafter, the present invention will be described in detail.

  The fluororesin composite material containing the solid lubricant in the present invention is not particularly limited as long as it is a fluororesin composite material containing a fluororesin and a solid lubricant.

  The fluorine-based resin is not particularly limited as long as it is a fluorine-containing resin. For example, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, polychlorotrifluoroethylene, tetrafluoroethylene-ethylene copolymer, Examples include tetrafluoroethylene-hexafluoropropylene copolymer and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, among which polytetrafluoroethylene and polychlorotrifluoroethylene are preferable, and polytetrafluoroethylene is particularly preferable. . If necessary, other components such as polyimide resin, polyamide resin, polyamideimide resin, silane-modified polyamideimide resin, epoxy resin, phenol resin, polyphenylene sulfide and other resin materials, glass fiber, aramid fiber, plasticizer And the like, and may contain a resin as described above containing iodine, bromine, chlorine and the like.

  Solid lubricants include molybdenum disulfide, tungsten disulfide, alumina, silica, iron oxide, chromium dioxide, boron nitride, silicon carbide, zinc sulfide, silver sulfide, copper sulfide, lead, tin, tantalum, bismuth, natural graphite, Examples thereof include solid lubricants such as synthetic graphite, various carbon blacks, and carbon fibers. Among these, carbon-based lubricants such as molybdenum disulfide and graphite are preferable, and graphite is particularly preferable.

  In the present invention, the composition ratio of the composite material is not particularly limited, but the fluororesin is preferably 50 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably 70 to 95% by mass. The solid lubricant is preferably 0.1 to 50% by mass, more preferably 1 to 40% by mass, and particularly preferably 5 to 30% by mass.

As the fluororesin-based composite material containing these solid lubricants, the above-described fluororesin and solid lubricant, if necessary, other components are dispersed and molded by a known method, for example, A state in which a fluorine-based resin (which may contain other resins) is melted, or in a powder or fine particle form, a fine solid lubricant and various resins are mixed and dispersed uniformly, or a fluorine-based resin Examples thereof include those obtained by dispersing a solid lubricant on the surface of a resin and molding the resin into a desired shape.
In addition, when the fluororesin-type composite material containing these solid lubricants is used as a piston band of a shock absorber, it is used by being pressure-bonded to a sliding portion of the piston with a cylinder. In this case, the thickness is usually 0.01 to 5 mm, preferably 0.1 to 2 mm, particularly preferably 0.2 to 1 mm. The thinner the thickness in this range, the easier it is to damage or break. The lubricating oil composition of the invention is particularly useful.

  Also, as the other sliding material that constitutes the sliding part with the fluororesin-based composite material containing solid lubricant, steel material, aluminum material, magnesium material, titanium material, copper material, lead material Or a metal-based material made of these various alloys, or chromium nitride, titanium nitride, diamond, diamondoid, diamond-like carbon (may be composed of carbon alone, and may contain metal, silicon, hydrogen, or the like. ) And the like, or carbon-based materials such as graphite and carbon fiber, and various materials such as the above-mentioned resin-based or various rubber-based materials. Among these, when various metal materials listed above are used, the sliding condition becomes more severe, so that the lubricating oil composition of the present invention is particularly useful.

  There is no restriction | limiting in particular as a lubricating base oil in the lubricating oil composition of this invention, The mineral base oil and synthetic base oil which are used for a normal lubricating oil can be used.

  Specifically, as the mineral base oil, the lubricating oil fraction obtained by subjecting the crude oil to atmospheric distillation obtained under reduced pressure is subjected to solvent removal, solvent extraction, hydrocracking, Examples include those refined by performing one or more treatments such as solvent dewaxing, hydrorefining, etc., or base oils produced by a method of isomerizing wax isomerized mineral oil, GTL WAX (Gas Liquid Wax).

  Specific examples of synthetic base oils include polybutene or hydrides thereof; poly-α-olefins such as 1-octene oligomers and 1-decene oligomers or hydrides thereof; ditridecyl glutarate, di-2-ethylhexyl adipate , Diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc .; neopentyl glycol ester, trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol pelargonate Examples thereof include polyol esters such as alkyl naphthalene, alkylbenzene, aromatic synthetic oils such as aromatic esters, and mixtures thereof.

  As the lubricating base oil in the present invention, the above mineral base oil, the above synthetic base oil, or an arbitrary mixture of two or more selected from these can be used. Examples thereof include one or more mineral base oils, one or more synthetic base oils, a mixed oil of one or more mineral base oils and one or more synthetic base oils, and the like.

The kinematic viscosity of the lubricating base oil used in the present invention is not particularly limited. For example, when used as a lubricating oil composition for a shock absorber, the kinematic viscosity at 40 ° C. is preferably 3 mm ² / s or more, more preferably. Is 6 mm ² / s or more, preferably 60 mm ² / s or less, more preferably 40 mm ² / s or less, still more preferably 20 mm ² / s or less, further preferably 10 mm ² / s or less, particularly preferably. Is preferably 9 mm ² / s or less.

  In addition, the viscosity index of the lubricating base oil used in the present invention is not particularly limited and is arbitrary. For example, when used as a lubricating oil composition for a shock absorber, the change in friction characteristics due to temperature is made as small as possible. In view of the above, the viscosity index is preferably 80 or more, more preferably 95 or more.

Next, (A) the acidic additive will be described.
The (A) acidic additive used in the lubricating oil composition of the present invention is not particularly limited as long as it is an acidic compound, and examples thereof include an acidic phosphorus compound, a carboxylic acid, and derivatives thereof.

  Specific examples of the phosphorus compound exhibiting acidity include phosphoric acid, acidic phosphoric acid ester, phosphorous acid, acidic phosphorous acid ester, thiophosphoric acid, acidic thiophosphoric acid ester, thiophosphorous acid, and acidic thiophosphorous acid ester. , Salts of (thio) (sub) phosphoric acid, salts of acidic (thio) (sub) phosphate esters, and mixtures thereof. Among these, it is preferable that it is 1 type, or 2 or more types chosen from the acidic organic phosphorus compound which does not contain sulfur from the point with a small time-dependent change of a friction characteristic, ie, an acidic (sub) phosphoric acid ester, and its salt.

  Here, as the acidic (sub) phosphoric acid ester, phosphoric acid esters represented by the general formula (1) (phosphoric acid diester, phosphoric acid monoester), phosphorous acid esters represented by the general formula (2) (Phosphorous acid diester, phosphorous acid monoester), and mixtures thereof are shown.

In the formula (1), R ¹ , R ² and R ³ are each independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, preferably 4 to 18 carbon atoms, and R ¹ , R ² and R ^3. At least one of them is a hydrogen atom.
In the formula (2), R ⁴ , R ⁵ and R ⁶ are each independently a hydrogen atom or a hydrocarbon group having 1 to 30 carbon atoms, preferably 4 to 18 carbon atoms, and R ⁴ , R ⁵ and R 6 ^At least one of ⁶ is a hydrogen atom.
In the above formula (2), when R ⁶ is an acidic phosphite diester having a hydrogen atom or an acidic phosphite monoester having R ⁵ and R ⁶ is a hydrogen atom, Although they may be represented by the following general formulas (3) and (4), they represent the same compound.

  Specific examples of the hydrocarbon group having 1 to 30 carbon atoms as described above include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. , Undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group, tricosyl group, tetracosyl group, pentacosyl group, hexacosyl group, heptacosyl Group, octacosyl group, nonacosyl group, triacontyl group and the like (these alkyl groups may be linear or branched); ethenyl group, propenyl group, butenyl group, pentenyl group, hexenyl group, heptenyl group, octenyl group , Nonenyl group, decenyl group, undecenyl group, Cenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group, hexadecenyl group, heptadecenyl group, octadecenyl group, nonadecenyl group, icocenyl group, henicosenyl group, dococenyl group, tricocenyl group, tetracocenyl group, pentacocenyl group, hexacocenyl group, heptacocenyl group, heptacocenyl group , Alkenyl groups such as nonacosenyl group and triacontenyl group (these alkenyl groups may be linear or branched, and the position of the double bond is arbitrary); carbon such as cyclopentyl group, cyclohexyl group, cycloheptyl group, etc. A cycloalkyl group of 5 to 7; a methylcyclopentyl group, a dimethylcyclopentyl group, a methylethylcyclopentyl group, a diethylcyclopentyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a methyl group An alkylcycloalkyl group having 6 to 11 carbon atoms such as a rucyclohexyl group, a diethylcyclohexyl group, a methylcycloheptyl group, a dimethylcycloheptyl group, a methylethylcycloheptyl group or a diethylcycloheptyl group; an aryl group such as a phenyl group or a naphthyl group; : Tolyl group, xylyl group, ethylphenyl group, propylphenyl group, butylphenyl group, pentylphenyl group, hexylphenyl group, heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, undecylphenyl group, dodecylphenyl group Each alkylaryl group having 7 to 18 carbon atoms such as a group (the alkyl group may be linear or branched, and the substitution position is arbitrary); benzyl group, phenylethyl group, phenylpropyl group, phenylbutyl group , Phenylpentyl group, Each arylalkyl group having 7 to 12 carbon atoms such as an hexylhexyl group (the alkyl group may be linear or branched, and the substitution position is arbitrary);

  In addition, as the salt of the above (phosphite) esters, specifically, acidic phosphoric acid monoester, acidic phosphoric acid diester, acidic phosphorous acid monoester, acidic phosphorous acid diester, etc., ammonia or carbon Nitrogen-containing compounds such as amine compounds containing only a hydrocarbon group of 1 to 30 or a hydroxyl group-containing hydrocarbon group in the molecule and / or a metal base are allowed to act, and part or all of the remaining acidic hydrogen is Examples thereof include neutralized salts.

  Specific examples of the nitrogen-containing compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, monononylamine, and monodecylamine. , Monoundecylamine, monododecylamine, monotridecylamine, monotetradecylamine, monopentadecylamine, monohexadecylamine, monoheptadecylamine, monooctadecylamine, monoethenylamine, monopropenylamine, monobutenyl Amine, monopentenylamine, monohexenylamine, monoheptenylamine, monooctenylamine, monononenylamine, monodecenylamine, monoundecenylamine, monododecenylamine, monoto Decenylamine, monotetradecenylamine, monopentadecenylamine, monohexadecenylamine, monoheptadecenylamine, monooctadecenylamine, dimethylamine, methylethylamine, diethylamine, methylpropylamine, ethylpropylamine, dipropyl Alkylamines such as amine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine and dioctylamine (the alkyl group and alkenyl group may be linear or branched; The position of the heavy bond is arbitrary); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine, Heptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanolamine, Examples thereof include alkanolamines such as dipentanolamine, dihexanolamine, diheptanolamine and dioctanolamine (the alkanol group may be linear or branched); and mixtures thereof.

  Of these, acidic phosphates and acidic phosphites are preferred in the present invention.

  In the present invention, the particularly preferable acidic phosphate ester is monobutyl acid phosphate, dibutyl acid phosphate, mono 2-ethylhexyl acid phosphate, di-2-ethylhexyl acid, because the durability and friction characteristics of the shock absorber can be suitably adjusted. Examples thereof include acidic phosphates having a C 4-18 alkyl group or alkenyl group such as phosphate, monooleyl acid phosphate, dioleyl acid phosphate, and mixtures thereof.

  In addition, even if the acidic additive used in the form of a salt with a basic compound is not completely neutralized, there is an influence on the fluororesin-based composite material. For example, even a compound in which a mixture of mono- and dialkyl zinc phosphates and an aliphatic amine compound such as a primary amine forms a salt in an equimolar amount is acidic in this case, so it is included in the acidic additives listed above. .

Specific examples of the carboxylic acid include carboxylic acids having 1 to 30 carbon atoms, preferably 8 to 30 carbon atoms, more preferably 12 to 24 carbon atoms, and alkyl or alkenyl groups, and derivatives thereof. It is done.
Examples of the carboxylic acid include hexanoic acid, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, octadecanoic acid, hydroxyoctadecanoic acid, nonadecanoic acid, eicosanoic acid, Heneicosanoic acid, docosanoic acid, tricosanoic acid, tetracosanoic acid, hexenoic acid, octenoic acid, nonenic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecenoic acid, octadecenoic acid, hydroxyoctadecenoic acid, Nonadecenoic acid, eicosenoic acid, heneicosenoic acid, docosenoic acid, tricosenoic acid, tetracosenoic acid (These alkyl groups and alkenyl groups may be linear or branched, and the position of the double bond of the alkenyl group is arbitrary.) Things like Other carboxylic acids, dicarboxylic acids, tricarboxylic acids, polycarboxylic acids such as tetracarboxylic acid. Among these, monocarboxylic acids having an alkyl group or alkenyl group having 12 to 18 carbon atoms such as oleic acid and stearic acid are preferable.

  Examples of the carboxylic acid derivative include, for example, a nitrogen-containing carboxylic acid, a salt obtained by allowing a metal base or alcohol to act on a carboxylic acid or a nitrogen-containing carboxylic acid, and neutralizing a part of the remaining acidic hydrogen, or Examples include esterified or etherified compounds.

  The nitrogen-containing carboxylic acid is not particularly limited as long as the carboxyl group and nitrogen are in the molecule, and the above-described nitrogen-containing compound is allowed to act on polycarboxylic acids such as dicarboxylic acid, tricarboxylic acid, and tetracarboxylic acid. Further, it may be a compound obtained by partially amidating, or may be a carboxylic acid containing a basic polar group as long as it exhibits acidity.

As carboxylic acid containing a basic polar group, the sarcosine represented by following General formula (5) and its derivative (s) are mentioned, for example.

In General Formula (5), R ⁷ and R ⁸ each independently represent hydrogen or an alkyl group or alkenyl group having 1 to 30 carbon atoms, and R ⁹ represents a single bond or an alkylene group having 1 to 4 carbon atoms. . In the present invention, a single bond means a direct bond, and here, R ⁹ does not exist and nitrogen and carbon are directly bonded. In the present invention, when the sarcosines are used, at least one of R ⁷ and R ⁸ in the general formula (5) is an alkyl group or an alkenyl group having 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms. It is desirable that

  Moreover, as a derivative | guide_body of sarcosines, it is amidation by making a C8-C30, preferably C12-C24 carboxylic acid act on an amino group or an imino group to the sarcosine represented by the said General formula (5). The compound etc. which were carried out are mentioned, for example, the compound etc. which are represented by General formula (6) are mentioned.

In the general formula (6), R ¹⁰ and R ¹¹ individually represent hydrogen, an alkyl group having 1 to 30 carbon atoms, or an alkenyl group, and at least one of R ¹⁰ and R ¹¹ has 8 to 30 carbon atoms. R ¹² represents a single bond or an alkylene group having 1 to 4 carbon atoms.

The nitrogen-containing carboxylic acid in the present invention is preferably a derivative of sarcosine represented by the general formula (6). In the general formula (5), R ⁷ is hydrogen, R ⁸ is a methyl group, R ^A sarcosine derivative obtained by reacting a carboxylic acid having an alkyl group or an alkenyl group having 8 to 30 carbon atoms with sarcosine in which ⁹ is a methylene group is more preferable. The alkyl group or alkenyl group having 8 to 30 carbon atoms is preferably a linear or branched alkyl group or alkenyl group having 12 to 24 carbon atoms, for example, a linear or branched group. Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, henicosyl group, docosyl group, tricosyl group, tetracosyl group, dodecenyl group, tridecenyl group, tetradecenyl group, pentadecenyl group , A hexadecenyl group, a heptadecenyl group, an octadecenyl group, a nonadecenyl group, an icocenyl group, a henicocenyl group, a dococenyl group, a tricocenyl group, a tetracocenyl group, and the like.

Among these carboxylic acids having an alkyl group or alkenyl group having 8 to 30 carbon atoms, oleic acid and stearic acid are particularly preferable.
Further, as the R ^11, preferably 1 to 4 hydrogen or carbon atoms, and particularly preferably a methyl group.
Further, as the R ^12, it is preferably a single bond or a 1 to 4 carbon atoms, particularly preferably a methylene group.
In the present invention, particularly preferred specific examples of the compound represented by the general formula (6) include N-oleoyl sarcosine represented by the formula (7).

  The blending amount of the (A) acidic additive in the lubricating oil composition of the present invention depends on the blending amount of the (B) basic additive, but is usually 0.01 to 10 mass based on the total amount of the lubricating oil composition. %, Preferably 0.05 to 5% by mass, particularly preferably 0.1 to 2% by mass. When the blending amount of the component (A) is less than 0.01% by mass, the anti-wear property or the friction adjusting effect is not exhibited, and even when it exceeds 10% by mass, the anti-wear property or the friction adjusting effect corresponding to the blending amount is obtained. It is not obtained economically.

Next, (B) the basic additive will be described.
The basic additive (B) used in the lubricating oil composition of the present invention is a basic compound having an alkyl group or alkenyl group having 8 or more carbon atoms and a basic polar group. The basic polar group here is not particularly limited, and examples thereof include nitrogen-containing polar groups such as amino group, imino group and amide group, and modified groups thereof.

  Specific examples of (B) basic additives include amine compounds having at least one alkyl group or alkenyl group having 8 or more carbon atoms in the molecule and derivatives thereof, and more specifically, (B1) carbon. Examples include amine compounds having an alkyl group or alkenyl group having 8 to 30 and derivatives thereof, and (B2) amine compounds having an alkyl group or alkenyl group having 31 to 400 carbon atoms and derivatives thereof.

As the component (B1), more specifically,
(B1-1) an aliphatic monoamine represented by the following general formula (8) or an alkylene oxide adduct thereof,
(B1-2) an aliphatic polyamine represented by the following general formula (9) and a derivative thereof,
(B1-3) Succinimide represented by the following general formula (10) or (11) and derivatives thereof,
(B1-4) an imidazoline compound represented by the following general formula (12) and a derivative thereof,
(B1-5) a fatty acid amide having an alkyl group or an alkenyl group having 8 to 30 carbon atoms,
Etc.

As the component (B2), more specifically,
(B2-1) Succinimide having an alkyl group or alkenyl group having 31 to 400 carbon atoms and a derivative thereof,
(B2-2) a polyamine having an alkyl group or an alkenyl group having 31 to 400 carbon atoms and a derivative thereof,
(B2-3) benzylamine having an alkyl group or alkenyl group having 31 to 400 carbon atoms and a derivative thereof,
And high molecular basic compounds such as

In the formula (8), R ¹³ represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms, and R ¹⁴ and R ¹⁵ individually represent 1 to 4 carbon atoms, preferably 2 to 2 carbon atoms. 3 represents an alkylene group, R ¹⁶ and R ¹⁷ each independently represent hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, and a and b each independently represent 0 to 10, preferably 0 to 6 And a + b = 0 to 10, preferably 0 to 6.

In the formula (9), R ¹⁸ represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms, R ¹⁹ represents an alkylene group having 1 to 4 carbon atoms, preferably 2 to 3 carbon atoms, R ²⁰ and R ²¹ each independently represent hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, and c represents an integer of 1 to 5, preferably 1 to 4.

In the general formulas (10) and (11), R ²² and R ²³ individually represent an alkyl group or an alkenyl group having 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms, and R ²⁴ and R ^25. Each independently represents an alkylene group having 1 to 4 carbon atoms, preferably 2 to 3 carbon atoms, and R ²⁶ represents a hydrogen atom or an alkyl group or alkenyl group having 1 to 30 carbon atoms, preferably 8 to 30 carbon atoms. N represents an integer of 1 to 7, preferably an integer of 1 to 3.

In the formula (12), R ²⁷ represents an alkyl group or alkenyl group having 8 to 30 carbon atoms, preferably 12 to 24 carbon atoms, R ²⁸ represents an ethylene group or propylene group, and R ²⁹ represents hydrogen or 1 to 30 carbon atoms. D represents an integer of 0 to 10, preferably 0 to 6.

The alkyl group or alkenyl group represented by R ¹³ , R ¹⁸ , R ²² , R ²³ and R ²⁷ may be linear or branched, but the carbon number thereof is 8 to 30, preferably 12 to 24 is desirable. By setting the carbon number of the alkyl group or alkenyl group to 8 to 30, a composition having more excellent friction characteristics can be obtained.
Specifically, the alkyl group or alkenyl group represented by R ¹³ , R ¹⁸ , R ²² , R ²³ and R ²⁷ is a straight chain having 8 to 30 carbon atoms as mentioned in the section of the nitrogen-containing carboxylic acid. Or a branched alkyl group or an alkenyl group is mentioned. Among these, a lauryl group, a myristyl group, a palmityl group, a stearyl group, an oleyl group, and the like are particularly preferable from the viewpoint of excellent friction adjustment effect.

Moreover, as group shown by R <^16> , R <^17> , R <^20> , R <^21> , R <^26> and R < ²⁹ >, specifically, it is C1-C1 mentioned by the term of hydrogen and the said acidic (sub) phosphate ester. There are 30 hydrocarbon groups.

(B1-1) As the aliphatic monoamine represented by the above formula (8) or an alkylene oxide adduct thereof, in the formula (8), R ¹⁶ and R ¹⁷ are each independently selected from the viewpoint of excellent friction reduction effect. , Hydrogen or an aliphatic monoamine having 1 to 6 carbon atoms and a = b = 0, R ¹⁶ and R ¹⁷ are hydrogen, and a and b are each independently 0 to 6 In addition, an alkylene oxide adduct of an aliphatic monoamine having a number of a + b = 1 to 6 is more preferably used, and an aliphatic monoamine is particularly preferable from the viewpoint of particularly excellent friction adjustment effect.

(B1-2) As the aliphatic polyamine represented by the formula (9), R ²⁰ and R ²¹ are each independently hydrogen or carbon in the formula (9) from the viewpoint of excellent friction adjustment effect. Aliphatic polyamines having an alkyl group of 1 to 6 are more preferably used, and aliphatic polyamines in which R ²⁰ and R ²¹ are hydrogen are particularly preferably used.
The substitution position of the amino group is preferably at the terminal carbon of the alkyl group, but it may be a carbon inside the terminal.

Further, (B1-3) the equation (10) or (11) include succinimide represented by, from the viewpoint of excellent friction modifying effect, equation (10) in ^{R 22} and ^{R 23} is 12 to 18 carbon atoms An alkyl group or an alkenyl group, R ²⁴ and R ²⁵ are bis-type succinimides having 1 to 4 carbon atoms, R ²² is an alkyl or alkenyl group having 12 to 18 carbon atoms in formula (11), A monotype succinimide in which R ²⁴ is an alkylene group having 1 to 4 carbon atoms and R ²⁶ is a hydrogen atom is particularly preferably used.

As the imidazoline compound represented by (B1-4) the equation (12), from the viewpoint of excellent friction modifying effect, ^{R 29} in formula (12), is hydrogen or an alkyl group having 1 to 6 carbon atoms An imidazoline compound is more preferably used.

Further, (B1-5) fatty acid amide compound having at least one alkyl group or alkenyl group having 8 to 30 carbon atoms, specifically, fatty acid having an alkyl group or alkenyl group having 8 to 30 carbon atoms or its Examples thereof include fatty acid amides obtained by reacting acid chlorides with ammonia, nitrogen-containing compounds such as amine compounds containing only hydrocarbon groups having 1 to 30 carbon atoms or hydroxyl group-containing hydrocarbon groups in the molecule.
Specific examples of the nitrogen-containing compound include the nitrogen-containing compounds mentioned in the section of the component (A) and the salt of (phosphorous) esters.

  Specific examples of fatty acid amides are lauric acid amide, lauric acid diethanolamide, lauric acid monopropanolamide, myristic acid amide, myristic acid diethanolamide, myristic acid monopropanolamide, and palmitic acid because of its excellent friction reducing effect. Amides, palmitic acid diethanolamide, palmitic acid monopropanolamide, stearic acid amide, stearic acid diethanolamide, stearic acid monopropanolamide, oleic acid amide, oleic acid diethanolamide, oleic acid monopropanolamide, coconut oil fatty acid amide, coconut oil Fatty acid diethanolamide, coconut oil fatty acid monopropanolamide, synthetic mixed fatty acid amide having 12 to 13 carbon atoms, synthetic mixed fatty acid diethanolamide having 12 to 13 carbon atoms Synthetic mixed fatty acid mono-propanol amide 12 to 13 carbon atoms, and mixtures thereof are particularly preferred.

  Among these, as the component (B1), specifically, in terms of excellent friction properties, laurylamine, lauryldiethylamine, lauryldiethanolamine, dodecyldipropanolamine, palmitylamine, stearylamine, stearyltetraethylenepentamine, Amine compounds such as oleylamine, oleylpropylenediamine, oleyldiethanolamine, oleyl succinimide, isostearyl succinimide, N-hydroxyethyl oleylimidazoline; alkylene oxide adducts of these amine compounds such as stearylamine ethylene oxide adducts; An alkylene oxide adduct of an amine compound; or a mixture thereof is particularly preferably used.

In addition, as (B2-1) succinimide having an alkyl group or an alkenyl group having 31 to 400 carbon atoms, in the above formulas (10) and (11), R ²² and R ²³ are preferably 31 to 400 carbon atoms. Can be exemplified by a succinimide which is an alkyl group or an alkenyl group having 40 to 350, and (B2-2) as a polyamine having an alkyl group or an alkenyl group having 31 to 400 carbon atoms, R ¹⁸ in the above formula (9) is Examples thereof include polyamines having 31 to 400 carbon atoms, preferably 40 to 350 alkyl groups or alkenyl groups. (B2-3) benzylamine having 31 to 400 carbon atoms, preferably 40 to 350 alkyl groups or alkenyl groups. And so on, in order to prevent wear and breakage of the composite material when the acidic additive in the composition is excessive Bets can be further basic compound having these alkyl or alkenyl group having a carbon number of 31 to 400 are also useful as an additive for dispersing the deterioration in the composition.

  On the other hand, as the derivative of the amine compound, specifically, for example, an amine compound such as the above formulas (8) to (12), a succinimide having 31 to 400 carbon atoms or an alkenyl group, an amine or Residues of benzylamine or the like by reacting monocarboxylic acid having 2 to 30 carbon atoms (fatty acid, etc.) or polycarboxylic acid having 2 to 30 carbon atoms such as oxalic acid, phthalic acid, trimellitic acid or pyromellitic acid. A so-called acid-modified compound obtained by neutralizing or amidating part or all of the amino group and / or imino group; an amine compound such as formulas (8) to (12), an alkyl group having 31 to 400 carbon atoms, or A so-called succinimide, amine or benzylamine having an alkenyl group is reacted with boric acid to neutralize part or all of the remaining amino group and / or imino group, so-called An oxalic acid-modified compound; an amine compound such as formulas (8) to (12), a succinimide having an alkyl group or an alkenyl group having 31 to 400 carbon atoms, an amine or benzylamine, an alkylene oxide such as ethylene oxide or propylene oxide A so-called alkylene oxide adduct of an amine compound; a modified product of an amine compound obtained by combining two or more modifications selected from these; and the like.

In the present invention, as the component (B), one type or two or more types selected from the various basic compounds described above can be used.
The amine compound modified with boric acid (for example, boric acid-modified succinimide) alone has little influence on the composite material, but is stronger than boric acid (for example, acidic phosphate ester or acidic sublimation). In view of the basicity of the phosphoric acid ester and the like, it is necessary to consider the basicity when used together with such a strong acid additive.

  The blending amount of the component (B) in the lubricating oil composition of the present invention is 0.01 to 10% by mass, preferably 0.05, based on the total amount of the composition, although it depends on the blending amount of the component (A). -5% by mass, more preferably 0.1-2% by mass. When the blending amount of the component (B) is less than 0.01% by mass, the effect of adjusting the friction is not exhibited, and even when it exceeds 10% by mass, the effect corresponding to the blending amount is not obtained, which is economically preferable. Absent.

  In the lubricating oil composition of the present invention, the blending ratio of the acidic additive (A) and the basic additive (B) may be adjusted for acid-base balance in consideration of the influence on the fluororesin composite material. The difference between the total number of moles of acid and the total number of moles of base (acid-base balance) is within 35%, preferably within 30%, more preferably within 25%, particularly preferably 20 It is desirable to blend so as to be within%. When the acid-base balance exceeds 35%, wear of the fluororesin-based composite material or elution of the solid lubricant becomes significant, and there is a possibility of breaking.

  The lubricating oil composition of the present invention may be added with any additive commonly used in lubricating oils as necessary, in order to further improve its performance, or depending on other purposes. Can do. Examples of such additives include friction modifiers, antiwear agents, antioxidants, fluidity improvers, viscosity index improvers, metal deactivators, metal detergents, corrosion inhibitors, and rust inhibitors. And various additives such as a demulsifier, an antifoaming agent, and a coloring agent.

  As the friction modifier, any compound usually used as a friction modifier for lubricating oils can be used, and friction modifiers other than the components (A) and (B) exemplified above, such as molybdenum dithiocarbamate. , Molybdenum-based friction modifiers such as molybdenum dithiophosphate, fatty acid esters having at least one alkyl group or alkenyl group having 6 to 30 carbon atoms, in particular, a linear alkyl group or linear alkenyl group having 6 to 30 carbon atoms in the molecule , Ashless friction modifiers such as aliphatic alcohols, aliphatic ethers, etc., or completely neutralized friction modifiers not corresponding to the components (A) and (B), based on the total amount of the composition, Usually, it is possible to make it contain in 0.01-5 mass%.

  As the antiwear agent, any compound usually used as an antiwear agent for lubricating oils can be used. For example, (sub-) phosphoric acid triesters, disulfides, sulfurized olefins, sulfurized oils and fats, dithiocarbamate, And sulfur-containing compounds such as zinc dithiocarbamate. These antiwear agents can be contained in the composition of the present invention usually in the range of 0.01 to 5% by mass based on the total amount of the composition.

  As the antioxidant, any compound usually used as an antioxidant for lubricating oils can be used. For example, 2,6-di-tert-butyl-p-cresol, 4,4′-methylenebis (2, 6-di-tert-butylphenol), octyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 3-methyl-5-tert-butyl-4-hydroxyphenyl substituted fatty acid esters, etc. And phenolic antioxidants such as phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, and dialkyldiphenylamine. These antioxidants can be contained in the composition of the present invention usually in the range of 0.01 to 5% by mass based on the total amount of the composition.

  As the viscosity index improver, any compound usually used as a viscosity index improver for lubricating oils can be used. For example, a polymer or copolymer of one or more monomers selected from various methacrylates So-called non-dispersed viscosity index improvers such as coalescence or hydrogenated products thereof, or so-called dispersed viscosity index improvers obtained by copolymerizing various methacrylic esters containing nitrogen compounds, non-dispersed or dispersed ethylene-α- Olefin copolymer (Examples of α-olefin include propylene, 1-butene, 1-pentene, etc.) or a hydride thereof, polyisobutylene or a hydrogenated product thereof, a hydride of styrene-diene copolymer, styrene- Examples thereof include maleic anhydride ester copolymers and polyalkylstyrene.

  The number average molecular weight of the viscosity index improver is usually 5,000 to 1,000,000, preferably 100,000 to 900,000 in the case of dispersed and non-dispersed polymethacrylates. In the case of the hydride, usually 800 to 5,000, preferably 1,000 to 4,000, but in the case of the ethylene-α-olefin copolymer or its hydride, usually 800 to 500,000, preferably The one of 3,000 to 200,000 is used. One or two or more compounds arbitrarily selected from the above viscosity index improvers can be contained in any amount. Content of a viscosity index improver is 0.1-20 mass% normally on a composition basis.

  As the fluidity improver, any compound usually used as a fluidity improver for lubricating oils can be used, and examples thereof include a polymethacrylate fluidity improver.

  Metal deactivators include imidazolines, pyrimidine derivatives, alkylthiadiazoles, mercaptobenzothiazoles, benzotriazoles or derivatives thereof, 1,3,4-thiadiazole polysulfides, 1,3,4-thiadiazolyl-2,5-bisdialkyldithio Examples thereof include carbamate, 2- (alkyldithio) benzimidazole, and β- (o-carboxybenzylthio) propiononitrile.

  Examples of metal detergents include alkali metal or alkaline earth metal sulfonates, phenates, salicylates, and phosphonates.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds.

  Examples of the rust inhibitor include petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, alkenyl succinic acid ester, and polyhydric alcohol ester.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of the antifoaming agent include silicone oil, fluorine-modified silicone oil, alkenyl succinic acid derivative, polyhydroxy aliphatic alcohol and long chain fatty acid ester, methyl salicylate and o-hydroxybenzyl alcohol, aluminum stearate, potassium oleate, N-dialkyl-allylamine nitroaminoalkanol, aromatic amine salt of isoamyl octyl phosphate, alkylalkylene diphosphate, metal derivative of thioether, metal derivative of disulfide, fluorine compound of aliphatic hydrocarbon, triethylsilane, dichlorosilane, alkylphenyl polyethylene Examples include glycol ether sulfide and fluoroalkyl ether.

  When these additives are contained in the lubricating oil composition of the present invention, the content is based on the total amount of the composition. In the fluidity improver, metal detergent, corrosion inhibitor, rust inhibitor, and demulsifier, It is usually selected in the range of 0.005 to 5% by mass, 0.005 to 1% by mass for the metal deactivator, and 0.0001 to 0.01% by mass for the antifoaming agent.

  In the lubricating oil composition of the present invention, among the compounds mentioned in the section of component (A) and component (B), the compound that is completely neutralized and shows neutrality is component (A) or component (B). Shall be excluded as not included. In addition, since phenolic antioxidants and compounds having alcoholic hydroxyl groups are considered to be very weak acids compared to strong acids such as phosphites, the effect on the fluororesin composite material is small (A) You may exclude from an ingredient. In addition, since the aromatic amine antioxidant is considered to be a very weak base as compared with the aliphatic amine compound, it may be excluded from the component (B) as having little influence on the fluororesin composite material.

  (A) component and (B) component which were illustrated above are mix | blended in the ratio prescribed | regulated to this application, and acidic additives and basic additives other than (A) component and (B) component which were illustrated above, and those similar to these When the above-mentioned fluororesin-based composite material is worn out or the solid lubricant is eluted, an effect equivalent to that of the present invention can be expected by appropriately adjusting the acid-base balance. In this case, the acid-base balance may slightly exceed 35% as long as the same effect as the present invention is obtained.

  As described above, in a device in which a fluororesin-based composite material is used for a sliding portion, such as a shock absorber in which the fluororesin-based composite material is used at a sliding portion with the cylinder of the piston, the wear of the composite material Alternatively, the lubricating method and lubricating oil composition of the apparatus capable of preventing breakage or elution of the solid lubricant can be obtained.

  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.

[Examples 1-6 and Comparative Examples 1-9]
Lubricating oil compositions (Examples 1 to 6) according to the present invention in which additives having the compositions shown in Tables 1 to 4 are blended with a lubricating base oil having a kinematic viscosity of 40 ° C. of 6.1 mm ² / s and for comparison The lubricating oil compositions (Comparative Examples 1 to 9) were prepared. The friction test shown below was performed on these compositions, and the presence or absence of breakage of the composite material mainly composed of a fluororesin containing graphite was evaluated.

In Tables 1 to 4, acid-base balances represented by the following formulas were calculated and written together.
Acid-base balance (%) = [Difference in the number of moles of (A) and (B) (absolute value: mmol / 100
g)] / [number of moles of (A) and (B) having the larger number (mmol / 100 g)] × 100
In addition, the number of moles of the component (A) and the component (B) was calculated from the (average) molecular weight and the added amount of each component.

(Friction test)
Using a SRV friction tester, the composite material having a thickness of about 0.8 mm is placed in a cylindrical jig for fixing the lower part of the test steel ball to be exposed, so that the composite material is exposed in a hemisphere as a sliding portion. A test steel ball was press-fitted from above and fixed. A test steel disk was set as a sliding material for the other party, a few drops of test oil were dropped on it, and a friction test was conducted under conditions of 110 ° C., constant overload and 3 hours.

  As apparent from Tables 1 to 4, when the acid-base balance of the component (A) and the component (B) exceeds 35%, the wear of the composite material mainly composed of fluororesin containing graphite is significantly broken (holes). When the acid-base balance is within 35%, it can be seen that no breakage (perforation) was reached. In addition, it turned out that the coloring degree of the lubricating oil accompanying the elution of graphite is so small that an acid-base balance is small.

Claims (3)

  A lubrication method for an apparatus having a sliding part, at least one of which is a fluororesin-based composite material containing a solid lubricant, wherein the sliding part comprises a lubricant base oil, (A) an acidic additive, and (B) a base. And the difference between the total number of moles (A) and the total number of moles (b) of (B) is within 35% with respect to the larger number of (a) and (b). Lubrication with a lubricating oil composition prepared as described above.   A lubricating oil composition for use in a device having a sliding part, at least one of which is a fluororesin-based composite material containing a solid lubricant, the lubricating oil composition comprising a lubricating base oil, (A) an acidic additive, And (B) the difference between the total number of moles (a) of (A) and the total number of moles (b) of (B) (a) and (b) A lubricating oil composition prepared so as to be within 35%.   The lubricating oil composition according to claim 2, wherein the sliding portion is a sliding portion composed of the composite material and a cylinder attached to a piston.