JPH11140476A - Lubricant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lubricant excellent in lubrication characteristics such as extreme pressure lubrication, friction resistance and abrasion resistance. SOLUTION: This lubricant is obtained by homogeneously dispersing a metal oxide particle complex surface-treated with an organic material, for example, in a liquid material. The metal oxide particle complex is preferably at least one kind selected from a silica particle complex, an alumina particle complex and a zirconia particle complex.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a lubricant. More specifically, the present invention relates to a lubricant having excellent lubricating properties such as extreme pressure resistance, abrasion resistance, and friction resistance.

[0002]

2. Description of the Related Art A lubricant is present between two moving bodies (equipment) so as not to cause damage to the relative planes, and is used to maintain a smooth state of motion. is there. Lubricants include liquid, solid, and semi-solid lubricants, and among them, liquid lubricants are most often used. Generally, liquid lubricants are classified into mineral oil-based, synthetic oil-based, emulsion-based, water-based, and liquid metal-based. Also, graphite, molybdenum disulfide and the like are known as solid lubricants, and grease and the like are known as semi-solid lubricants.

The functions required of the above lubricant include, for example, cooling, reduction of friction, reduction of abrasion, suppression of seizure, sealing effect, rust prevention, clean dispersion and the like. However, it is rare to need all of the above functions at the same time,
The role mainly required of the lubricant is determined in each case depending on the place where the lubricant is used, the design condition of the machine, and the like. For this reason, depending on where the lubricant is used, the design status of the machine, etc.
For example, various additives have been used to improve the lubricating properties of the lubricant.

[0004]

However, in general, a lubricant containing solid particles, especially a solid lubricant, has a lubricating function for a material having a softer material than the solid particles or the solid lubricant on the above-mentioned relative surface. Cannot be fully exhibited. Further, in the case of a lubricant in which lubricating properties such as extreme pressure resistance, friction resistance, and abrasion resistance are reduced, for example, a solid particle dispersed in a liquid material, the solid particles are stably dispersed in the liquid material. It is difficult. Accordingly, the lubricant causes a decrease in lubricating properties such as extreme pressure resistance, friction resistance, and abrasion resistance.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a lubricant excellent in lubricating properties such as extreme pressure resistance, friction resistance, and abrasion resistance. .

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventors have found that a lubricant containing a metal oxide particle composite surface-treated with an organic substance has extreme pressure resistance and abrasion resistance. The present inventors have found that the lubricating properties such as lubricity and friction resistance are excellent, and have completed the present invention.

[0007] That is, the lubricant according to the first aspect of the present invention is characterized in that in order to solve the above-mentioned problems, the lubricant contains a metal oxide particle composite surface-treated with an organic substance.

According to a second aspect of the present invention, there is provided a lubricant according to the first aspect, wherein:
The metal oxide particle composite is obtained by treating a metal oxide particle with an organic substance having a reactive group for the metal oxide particle.

According to a third aspect of the present invention, there is provided a lubricant according to the first or second aspect, wherein the metal oxide particle composite comprises silica particles dispersed therein. In the dispersion, at least one polysiloxane group per molecule is provided and at least one “Si—OR ¹ group” (R ¹ is a hydrogen atom, an alkyl group and an acyl group) in the polysiloxane group. and at least one group selected from the group consisting of radicals, the alkyl and acyl groups a group which may be substituted; when R ¹ are a plurality in one molecule, there a plurality of R ¹ are identical to each other Or different) may be obtained by treating the silica particles with an organic polymer (P) containing the same.

According to a fourth aspect of the present invention, there is provided a lubricant according to any one of the first to third aspects, further comprising a liquid material. .

According to the above structure, the metal oxide particle composite has excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance with an average particle diameter of, for example, 1 μm or less. Therefore, it is possible to provide a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance.

Further, the metal oxide particle composite reacts, for example, the metal oxide particles with an organic substance having a reactive group for the metal oxide particles, thereby converting the metal oxide particles to the metal oxide particles. A metal oxide particle composite having excellent dispersibility in various media such as a liquid substance can be obtained by being treated with an organic substance having a reactive group with respect to. The metal oxide particle composite is preferably at least one selected from the group consisting of a silica particle composite, an alumina particle composite, and a zirconia particle composite. In addition, the organic material is preferably at least one organic polymer selected from the group consisting of (meth) acrylic resin, polyolefin, polyester, modified polyolefin, modified polyester, and olefin / ester copolymer. . When the metal oxide particle composite is a silica particle composite, the content of the organic substance in the silica particle composite is preferably in the range of 5% by weight to 80% by weight.

In particular, the metal oxide particles are silica particles, the organic substance has at least one polysiloxane group per molecule, and at least one "Si-OR ¹ " In the case of an organic polymer (P) containing a group, the silica particles are treated (for example, hydrolyzed or condensed) with the organic polymer (P) in a dispersion liquid in which the silica particles are dispersed, A silica particle composite having better dispersibility in various media such as a liquid substance can be obtained. Therefore, it is possible to provide a lubricant having more excellent lubrication characteristics.

When a silica particle composite is obtained as the metal oxide particle composite, the metal oxide particle composite has at least one polysiloxane group per molecule, And in the polysiloxane group, at least one “Si—OR ¹ group” (R ¹ is at least one group selected from the group consisting of a hydrogen atom, an alkyl group, and an acyl group; group a group which may be substituted; when the R ¹ are a plurality in one molecule, an organic polymer (P) containing a plurality of R ¹ may be the being the same or different), organic polymers (P) It may be obtained by hydrolysis or condensation alone or with a hydrolyzable silane compound (H).

That is, silica particles having a particle diameter of several nm to several hundreds of nm have a large cohesive force between the particles, and therefore usually form an aggregate having a particle diameter of several μm or more. Also,
The cohesive force between the silica particles is remarkably greater than the affinity between the silica particles and another medium such as a liquid substance, and it is very difficult to disperse the silica particles in a liquid substance at 1 μm or less. However, silica particle composites
Since an organic substance, preferably an organic polymer, is present on the surface of the silica particles, the cohesive force between the silica particles can be reduced. For this reason, the silica particle composite has excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance. In addition, since the particles are dispersed with an average particle diameter of 1 μm or less, the relative surfaces of the equipment are not damaged. Therefore, the lubricant containing the silica particle composite is particularly excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance.

Further, when the organic polymer is, for example, a block polymer or a graft polymer, it is possible to obtain a silica particle composite having better dispersibility in various media such as liquid substances. Therefore, it is possible to provide a lubricant having more excellent lubrication characteristics.

Hereinafter, the present invention will be described in detail. The lubricant according to the present invention comprises a metal oxide particle composite obtained by chemically bonding an organic substance to the surface of a metal oxide particle, that is, a metal oxide particle composite surface-treated with an organic substance. I have.

The metal oxide particles according to the present invention include:
It is not particularly limited, and specifically, for example, M
gO, Al ₂ O ₃ , SiO ₂ , TiO ₂ , VO ₂ , V ₂
O ₅ , Cr ₂ O ₃ , MnO, MnO ₂ , Mn ₂ O ₃ , M
n ₂ O ₇ , MnO ₄ , FeO, Fe ₃ O ₄ , α-Fe ₂
O ₃ , Cu ₂ O, CuO, GeO ₂ , CoO, Co ₂ O
₃ , Co ₃ O ₄ , NiO, RbO ₂ , SrO, Zr
O ₂ , NbO ₂ , Nb ₂ O ₅ , Nb ₂ O ₃ , MoO ₂ ,
MoO ₃ , Mo ₂ O ₅ , Ag ₂ O, CdO, SnO, S
nO ₂ , Sb ₂ O ₄ , CsO, BaO, HfO, Ta ₂
O ₃ , Ta ₂ O ₅ , WO ₃ , W ₂ O ₅ , WO ₂ , Tl ₂
O, PbO, PbO ₂ , Bi ₂ O ₃ , CeO ₂ , Pr ₂
O _3, and the like Nd ₂ O _3, for example, it is possible to use particles of an oxide of a single metal element, the oxidation state is not limited in particular.

When composite metal oxide particles are used as the metal oxide metal oxide particles, the oxide particles of the single metal element may be used as a mixture or mixed metal oxide particles. May be used.

Specific examples of the above composite metal oxide include, for example, Mg ₂ Al ₂ O ₄ , MnFe ₂ O ₄ , Fe
Fe ₂ O ₄ (Fe ₃ O ₄ ), CoFe ₂ O ₄ , NiFe
₂ O ₄ , CuFe ₂ O ₄ , ZnFe ₂ O ₄ , MgFeO
₄ , Cu _0.5 Zn _0.5 Fe ₂ O ₄ , MnCo ₂ O ₄ , P
bCrO ₄ , CdCr ₂ O ₄ , MgCr ₂ O ₄ , NiC
o ₂ O ₄ , NiMnCo ₄ O ₈ , NiCr ₂ O ₄ , Sn
Zn ₂ O ₄ , TiZn ₂ O ₄ , SnCo ₂ O ₄ , ZnC
r ₂ O ₄ , LaMnO ₃ , SrMnO ₃ , LaFe
O ₃ , MgWO ₄ , SrTiO ₃ , CaTiO ₃ , Ge
TiO ₃ , SrZrO ₃ , ZrV ₂ O ₇ , V ₃ Zr ₃ O
₇ , V ₃ Ti ₆ O ₁₇ , and Zn ₃ V ₃ O ₈ . These composite metal oxides may include a portion (phase) in which oxides of a single metal element are separated from each other.

Furthermore, as the type of metal oxide used in the present invention, _2-for example, V ₂ O ₅ · H ₂ O and VO
A hydrate of vanadium oxide such as H ₂ O can also be used.

These metal oxide particles may be used alone or in combination of two or more. Among these metal oxide particles, silica particles,
Alumina particles and zirconia particles are particularly preferably used.

The organic substance according to the present invention is not particularly limited as long as it can treat the above-mentioned metal oxide particles, and may be either a low molecular compound or a high molecular compound.

Examples of the low molecular compound that can treat the above-mentioned metal oxide particles include silane coupling agents, alkoxys, halides, alcohols, and the like.
Examples include amines, olefins, alkynes, organic acids and esters thereof.

Among the above low molecular compounds, examples of the silane coupling agent include, for example, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, tetramethoxysilane , Methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, tetraethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, hexyltrimethoxysilane, decyltri Methoxysilane, hexamethyldisilazane, N, O- (bistrimethylsilyl) acetamide, N, N-bis (trimethylsilylurea), tert- Tyldimethylchlorosilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Silane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane Γ-methacryloxypropyltriethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl)
-Γ-aminopropyltrimethoxysilane, N-β-
(Aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-
Examples include aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like.

Specific examples of the alkoxys other than those exemplified as the silane coupling agent described above include, for example,
Examples thereof include alkali metal salts and alkaline earth metal salts of alcohols described below.

As the halide, specifically, a hydrogen atom of a hydrocarbon is a halogen atom (fluorine, chlorine, bromine,
E.g., halomethane, haloethane, halopropane, halobutane, halopentane, halohexane, haloheptane, halooctane, cyclohexyl halide, haloethene, 3-halopropene, 1-halo-2-butene, 3-halopropene, benzyl Halide,
α-, β-phenylethyl halide, diphenylmethyl halide, triphenylmethyl halide, dihalomethane, trihalomethane, tetrahalomethane, 1,1-dihaloethane, 1,2-dihaloethane, trihaloethylene,
Halogenated benzal, benzotrihalide and the like can be mentioned.

As the alcohols, specifically, for example, methanol, ethanol, n-propanol, n-propanol
Butanol, n-pentanol, n-hexanol, n
-Heptanol, n-octanol, n-decyl alcohol, n-dodecyl alcohol, n-tetradecyl alcohol, n-hexadecyl alcohol, n-octadecyl alcohol, isopropanol, isobutanol, s
ec-butanol, tert-butanol, isopentanol, 2-methyl-1-butanol, tert-pentanol, cyclopentanol, cyclohexanol,
Allyl alcohol, crotyl alcohol, methyl vinyl carbinol, benzyl alcohol, α-phenylethyl alcohol, β-phenylethyl alcohol, diphenylcarbinol, triphenylcarbinol, cinnamyl alcohol, ethylene glycol, propylene glycol, 1,3- Propanediol, glycerin, pentaerythritol and the like.

As the amines, specifically, for example,
Methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, n-
Propylamine, di-n-propylamine, tri-n-
Propylamine, isopropylamine, n-butylamine, isobutylamine, sec-butylamine, ter
t-butylamine, cyclohexylamine, benzylamine, α-phenylethylamine, β-phenylethylamine, ethylenediamine, tetramethylenediamine,
Hexamethylenediamine, tetramethylammonium hydroxide, aniline, methylaniline, dimethylaniline,
Diphenylamine, triphenylamine, o-, m-,
p-toluidine, o-, m-, p-anisidine, o-,
m-, p-chloroaniline, o-, m-, p-bromoaniline, o-nitroaniline and the like.

Specific examples of the olefins include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-octene.
Nonene, 1-decene, cis-2-butene, trans-2-butene, isobutylene, cis-2-pentene, trans-2-pentene, 3-methyl-1-butene, 2-methyl-2-butene, 2, 3-dimethyl-2-butene and the like.

Examples of the alkynes include, for example, acetylene, propyne, 1-butyne, 1-pentyne, 1-hexyne, 1-heptin, 1-octyne, 1-octyne,
Nonin, 1-desine, 2-butyne, 2-pentyne, 3-
Methyl-1-butyne, 2-hexyne, 3-hexyne,
3,3-dimethyl-1-butyne, 4-octyne, 5-decyne and the like.

As the organic acids, specifically, for example,
Formic, acetic, propionic, butyric, valeric, caproic, caprylic, capric, lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, cyclohexanecarboxylic, phenylacetic, benzoic Acid, o-, m-, p-toluic acid, o
-, M-, p-chlorobenzoic acid, o-, m-, p-bromobenzoic acid, o-, m-, p-nitrobenzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, p-hydroxybenzoic acid Carboxylic acids such as acid, anthranilic acid, m-aminobenzoic acid, p-aminobenzoic acid, o-, m-, p-methoxybenzoic acid; methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, pentane Sulfonic acid, heptanesulfonic acid, nonanesulfonic acid, undecanesulfonic acid, tridecanesulfonic acid,
Pentadecanesulfonic acid, heptadecanesulfonic acid, ci
s-8-heptadecenesulfonic acid, cis, cis-8,11-heptadecadienesulfonic acid, cis, cis, cis-octadecatrienesulfonic acid, cyclohexanesulfonic acid, phenylmethanesulfonic acid, benzenesulfonic acid, o- , M
-, P-toluenesulfonic acid, o-, m-, p-chlorobenzenesulfonic acid, o-, m-, p-bromobenzenesulfonic acid, o-, m-, p-nitrobenzenesulfonic acid, o-, m- , P-sulfobenzoic acid, o-, p-phenolsulfonic acid, o-, m-, p-sulfanilic acid,
sulfonic acids such as o-, m-, p-methoxybenzenesulfonic acid; and carbamic acids.

The organic acid esters are not particularly limited, but specific examples include formic acid,
Esters such as acetic, propionic, butyric, valeric, caproic, and carbamic acids.

On the other hand, specific examples of the high molecular compound include (meth) acrylic resin, polystyrene, polyvinyl acetate, polyolefin such as polyethylene and polypropylene, and polyester such as polyvinyl chloride, polyvinylidene chloride and polyethylene terephthalate. ,and,
These copolymers, and organic resins such as modified resins obtained by introducing at least one functional group selected from the group consisting of amino groups, epoxy groups, hydroxyl groups, and carboxyl groups into a part of these polymers. Polymers.

The structure of the organic polymer may be linear or branched, and may have a crosslinked structure. In particular, when the organic polymer is, for example, a block polymer or a graft polymer, since the dispersibility in various media such as a liquid substance becomes higher,
More preferred.

The organic polymer is more specifically selected from the group consisting of, for example, (meth) acrylic resin, polyolefin, polyester, modified polyolefin, modified polyester, and olefin / ester copolymer. More preferably, it is at least one polymer. As the polyolefin, the polyester, and the olefin / ester copolymer, conventionally known ones can be adopted and are not particularly limited. The modified polyolefin is a compound obtained by substituting a part of the hydrogen atoms of the polyolefin with at least one substituent selected from the group consisting of an amino group, an epoxy group, a hydroxyl group, and a carboxyl group.
The modified polyester is a compound obtained by substituting a part of the hydrogen atoms of the polyester with at least one substituent selected from the group consisting of an amino group, an epoxy group, a hydroxyl group, and a carboxyl group. Therefore, it is possible to provide a lubricant having more excellent lubrication characteristics. Only one kind of these organic substances may be used, or two or more kinds may be used in combination.

Among the above organic substances, polymers (copolymers) having (meth) acrylic resin as a structural unit, such as (meth) acrylic resin, (meth) acrylic-styrene resin, (meth) acrylic-polyester resin, etc. ) Are more preferable for constituting the silica particle composite according to the present invention.

In order to form the alumina particle composite and the zirconia particle composite according to the present invention, a silane coupling agent and an organic acid are more preferable because of good reactivity with alumina and zirconia. Coupling agents are particularly preferred.

The content of the organic substance in the metal oxide particle composite according to the present invention is not particularly limited.
What is necessary is just to set suitably according to the kind of a metal oxide particle, etc.

From the viewpoint of dispersibility, the metal oxide particle composite preferably has an average particle size in the range of 5 nm to 1 μm, more preferably 5 nm to 500 nm, and more preferably 5 nm to 500 nm. More preferably, it is within the range of 100 nm. When the average particle diameter is less than 5 nm, the surface energy of the metal oxide particle composite becomes too high, so that aggregation or the like is likely to occur. on the other hand,
If the average particle size exceeds 1 μm, for example, the particles cannot be uniformly dispersed in a liquid substance, and the relative surfaces of the equipment may be damaged. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

The coefficient of variation of the particle diameter of the metal oxide particle composite is preferably 50% or less, more preferably 30% or less. If the coefficient of variation exceeds 50%, that is, if the particle size distribution of the metal oxide particle composite is too wide, the particle diameter of the metal oxide particle composite will be too large and, for example, dispersed uniformly in a liquid substance. And the relative surfaces of the equipment may be damaged. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

Hereinafter, the metal oxide particle composite of the present invention will be described in particular with silica particle composite, alumina particle composite,
And a zirconia particle composite as an example.

The silica particle composite according to the present invention is a composite obtained by chemically bonding an organic substance, preferably an organic polymer, to the surface of silica particles, that is, a composite in which silica particles are surface-treated with an organic polymer. is there.

The silica particle composite according to the present invention preferably has an average particle size in the range of 5 nm to 1 μm, more preferably in the range of 5 nm to 500 nm, and more preferably in the range of 5 nm to 100 nm. It is more preferred that there be. When the average particle size is less than 5 nm,
Since the surface energy of the silica particle composite becomes too high, aggregation or the like is likely to occur. On the other hand, the average particle diameter is 1μ
If it exceeds m, for example, it will not be possible to uniformly disperse it in a liquid substance, and there will be a risk of damaging the relative surfaces of the equipment. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

Further, the coefficient of variation of the particle diameter of the silica particle composite is preferably 50% or less, more preferably 30% or less. If the coefficient of variation exceeds 50%, that is, if the particle size distribution of the silica particle composite is too wide, the particle size of the silica particle composite will be too large, for example, it can be uniformly dispersed in a liquid substance. In addition to this, there is a risk of damaging the relative surfaces of the equipment.
Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

The average particle diameter of the silica particles constituting the silica particle composite is not particularly limited, but may be 0.5 to 0.5.
more preferably in the range of from 500 nm to 500 nm,
More preferably, it is in the range of 1 nm to 100 nm. If the average particle size is less than 0.5 nm, a lubricant excellent in lubricating properties such as extreme pressure properties may not be obtained. On the other hand, when the average particle diameter exceeds 500 nm, a lubricant excellent in friction resistance may not be obtained.

The content of the organic substance in the silica particle composite is not particularly limited, but when the organic substance is an organic polymer, it is more preferably in the range of 5% by weight to 80% by weight. The composition of the organic polymer, the presence or absence of a functional group, the structure (shape), the weight average molecular weight (Mw), etc.
There is no particular limitation, and various known organic polymers can be used. The structure of the organic polymer may be linear or branched, and may have a crosslinked structure. In particular, when the organic polymer is, for example, a block polymer or a graft polymer, for example, the dispersibility in various media such as a liquid substance becomes higher, so that it is more preferable.

Usually, silica particles having a particle diameter of several nm to several hundreds nm have a large cohesive force between the particles, so that they become aggregates having a particle diameter of several μm or more. Further, the cohesive force between the silica particles is remarkably large as compared with the affinity between the silica particles and another medium such as a liquid substance, and the silica particles are 1 μm
It is very difficult to disperse in a liquid substance below. However, in the silica particle composite according to the present invention, since an organic substance, preferably an organic polymer, is present on the surface of the silica particles, the cohesive force between the silica particles can be reduced. For this reason, the silica particle composite has excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance. In addition, since the particles are dispersed with an average particle diameter of 1 μm or less, the relative surfaces of the equipment are not damaged.
Therefore, the lubricant containing the silica particle composite is particularly excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance.

Further, as described above, when the organic polymer is, for example, a block polymer or a graft polymer, it is possible to obtain a silica particle composite having better dispersibility in various media such as liquid substances. it can. Therefore, it is possible to provide a lubricant having more excellent lubrication characteristics. An example of the method for producing the silica particle composite will be described later in detail.

In the alumina particle composite according to the present invention, the alumina particles are surface-treated with an organic substance, preferably an organic substance having a reactive group for the alumina particles, and the surface of the alumina particles is coated with a reactive group for the alumina particles. Is a complex formed by chemically bonding an organic substance having

The alumina used in the present invention includes crystalline alumina such as α-alumina; γ-alumina;
In addition to amorphous alumina such as δ-alumina; hydroxide alumina such as boehmite; etc., alumina containing other components such as alkali metals, alkaline earth metals, and transition metals, as long as the performance of alumina is not impaired. You may. The content of these components other than alumina is based on the weight of alumina.
Preferably, it is in the range of 0.1% to 99% by weight.

The average particle diameter of the alumina particles constituting the alumina particle composite is not particularly limited.
It is more preferably in the range of 0.5 nm to 500 nm, and still more preferably in the range of 1 nm to 100 nm. If the average particle size is less than 0.5 nm, a lubricant excellent in lubricating properties such as extreme pressure properties may not be obtained. On the other hand, the average particle diameter is 500 n
If it exceeds m, a lubricant having excellent friction resistance may not be obtained.

The alumina particle composite according to the present invention preferably has an average particle diameter in the range of 5 nm to 1 μm, more preferably in the range of 5 nm to 500 nm, and more preferably in the range of 5 nm to 100 nm. It is more preferred that there be. If the average particle size is less than 5 nm, the surface energy of the alumina particle composite becomes too high, so that aggregation or the like is likely to occur. On the other hand, when the average particle size exceeds 1 μm, for example, the particles cannot be uniformly dispersed in a liquid substance, and the relative surfaces of the equipment may be damaged. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

The coefficient of variation of the particle diameter of the alumina particle composite is preferably 50% or less, more preferably 30% or less. If the coefficient of variation exceeds 50%, that is, if the particle size distribution of the alumina particle composite is too wide, the particle diameter of the alumina particle composite will be too large, for example, it can be uniformly dispersed in a liquid substance. In addition to this, there is a risk of damaging the relative surfaces of the equipment. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

The content of the organic substance in the alumina particle composite is not particularly limited, but may be 0.01% by weight.
It is preferably in the range of from 50 to 50% by weight, more preferably in the range of from 0.1 to 30% by weight.
When the content of the organic substance is less than 0.01% by weight, for example, aggregation occurs when neutralizing a dispersion obtained by dispersing the alumina particle composite in a dispersion medium, and the dispersion stability deteriorates.
Good lubrication properties may not be obtained. If the content of the organic substance exceeds 50% by weight, it may not be possible to obtain a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance and friction resistance.

Further, in the zirconia particle composite according to the present invention, the zirconia particles are surface-treated with an organic substance, preferably an organic substance having a reactive group for the zirconia particles, and the surface of the zirconia particles is coated with the reactive group for the zirconia particles. Is a complex formed by chemically bonding an organic substance having

The zirconia used in the present invention may be either a badeleyite type or a zirconia type, and zirconia containing other components such as an alkali metal, an alkaline earth metal, and a transition metal within a range that does not impair the performance of the zirconia. It may be. The content of components other than zirconia is 0.1% by weight to 9% by weight based on the weight of zirconia.
Preferably it is in the range of 9% by weight.

The average particle diameter of the zirconia particles constituting the zirconia particle composite is not particularly limited, but is preferably in the range of 0.5 nm to 500 nm, and more preferably in the range of 1 nm to 100 nm. Is more preferable. If the average particle size is less than 0.5 nm, a lubricant excellent in lubricating properties such as extreme pressure properties may not be obtained. On the other hand, when the average particle diameter is 500
If it exceeds nm, a lubricant excellent in friction resistance may not be obtained.

The zirconia particle composite according to the present invention comprises:
The average particle size is preferably in the range of 5 nm to 1 μm, more preferably in the range of 5 nm to 500 nm, and even more preferably in the range of 5 nm to 100 nm. When the average particle diameter is less than 5 nm, the surface energy of the zirconia particle composite becomes too high, so that aggregation or the like is likely to occur. On the other hand, when the average particle size exceeds 1 μm, for example, the particles cannot be uniformly dispersed in a liquid substance, and the relative surfaces of the equipment may be damaged. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

Further, the coefficient of variation of the particle diameter of the zirconia particle composite is preferably 50% or less, more preferably 30% or less. If the coefficient of variation exceeds 50%, that is, if the particle size distribution of the zirconia particle composite is too wide, the particle diameter of the zirconia particle composite will be too large, for example, it can be uniformly dispersed in a liquid substance. In addition to this, there is a risk of damaging the relative surfaces of the equipment. Therefore, it becomes impossible to obtain a lubricant having excellent lubrication characteristics.

The content of the organic substance in the zirconia particle composite is not particularly limited, but is preferably in the range of 0.01% by weight to 50% by weight.
More preferably, it is in the range of 30% by weight to 30% by weight. If the content of the organic substance is less than 0.01% by weight, for example, when a dispersion obtained by dispersing the zirconia particle composite in a dispersion medium is neutralized, agglomeration occurs, dispersion stability is deteriorated, and good Lubrication properties may not be obtained. If the content of the organic substance exceeds 50% by weight, it may not be possible to obtain a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance and friction resistance.

Normally, a dispersion containing alumina particles or zirconia particles cannot maintain stable dispersibility unless it is under strong acidity, and has a problem that aggregation and gelation are caused when neutralized. doing. For this reason, it is difficult to use these alumina particle dispersion liquid or zirconia particle dispersion liquid as a lubricant because of problems such as corrosion of equipment due to acid and safety. However, the alumina particle composite and the zirconia particle composite according to the present invention, as described above, because an organic substance is present on the surface of the alumina particles or zirconia particles, may weaken the cohesive force between these metal oxide particles. it can. For this reason, the alumina particle composite and the zirconia particle composite have excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance. Therefore, the lubricant containing the alumina particle composite or the zirconia particle composite is particularly excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance. Further, the lubricant containing the alumina particle composite and the zirconia particle composite does not cause corrosion of the equipment due to acid, and is excellent in safety.

The lubricant according to the present invention contains the above-described metal oxide particle composite, but is preferably obtained by mixing or dispersing the metal oxide particle composite in a liquid substance.

When the lubricant according to the present invention is obtained by mixing or dispersing the metal oxide particle composite in a liquid substance,
That is, the liquid substance used when the lubricant contains the metal oxide particle composite and the liquid substance may be water alone or an oily substance alone, or a mixture of water and an oily substance. Is also good. When the liquid substance is a mixture of water and an oily substance, the oily substance may be dissolved in water, or may be dispersed or emulsified. Or conversely, water may be dissolved in the oily substance, or may be dispersed or emulsified. However, when the liquid material contains water and the relative surface of the equipment moving through the lubricant, that is, the contact surface with the lubricant is a metal, a rust inhibitor is added to the liquid material. It is preferred to add.

Examples of the oily substances that can be used as required in the present invention include, for example, “Petroleum, Lubricants, Petrochemicals Series II Lubricating Oil (No. 2
Times) Base oil (top), Petrotech, Vol. 18, No. 6, 479-
485 (1995) "and" Petroleum, Lubricants and Petrochemicals Series II Lubricants (3rd) Base Oil (Bottom), Petrotech, Vol. 18, No. 7, pp. 584-587 (1995) "
, A conventionally known lubricating oil or the like can be used, but is not particularly limited.

Specific examples of the oily substance include paraffinic mineral oil refined from a crude oil rich in paraffinic hydrocarbons; so-called mixed base mineral oil / mixed base mineral oil produced from intermediate base crude oil; Naphthenic mineral oil containing a large amount of paraffin; single oil such as whale oil, tallow, lard, or animal oil obtained by mixing these oils with petroleum oil; vegetable oil such as rapeseed oil, soybean oil, coconut oil; solvent such as methyl ethyl ketone Solvent dewaxed oil obtained by separating wax that is difficult to dissolve at low temperature by diluting and filtering. Separation by selectively trapping long molecular wax in pores of zeolite-based catalyst and cutting. A catalytic dewaxing oil obtained by converting the structure of the wax into an active ingredient without discarding;

Other oily substances include, for example, solvent-refined oils obtained by extracting and removing polycyclic aromatic and polycyclic naphthene components, sulfur compounds, and the like into a solvent phase; rich in reactivity with hydrogen Hydrogen finishing oil with improved dye stability, thermal stability, oxidation stability, etc. by removing sulfur and nitrogen compounds and modifying unsaturated components; sulfur and nitrogen compounds by hydrogenating at high temperature and pressure And hydrogenolysis obtained by cycloparaffinization by polycyclic aromatic decomposition, ring opening, side-chain dealkylation, aromatic nucleus hydrogenation, or isoparaffinization by isomerization of linear components Oil;

Further, as an oily substance other than the above, for example, an α-olefin having a double bond at a terminal and having 6 to 14 carbon atoms obtained by wax decomposition or ethylene polymerization in the presence of a Friedel-Crafts catalyst polymerization,
Hydrogenation, poly-α- obtained by distilling and removing low molecular substances
Olefin; Alkyl aromatic obtained by alkylating benzene ring with olefin obtained by dehydrogenation of kerosene oil, wax pyrolysis, or ethylene polymerization; Naphtha C
Utilizing butane and butylene of the C ₄ component remaining after extracting butadiene from the ₄ fraction, the C ₄ component is polymerized in the presence of a Friedel-Crafts catalyst, the catalyst is separated by alkali washing or the like, and low-molecular substances are separated. Polybutene obtained by removal; dibasic organic acid using petroleum alcohol and animal and vegetable oil-based organic acids such as caprylic acid / capric acid contained in, for example, beef tallow, soy oleic acid, coconut oil, palm oil, etc. And ester-based synthetic oils such as diesters of carboxylic acids with monohydric alcohols and polyol esters of monobasic organic acids with polyhydric alcohols.

Further, other oily substances other than those described above include
For example, an ester of a phosphoric acid compound, which is an inorganic acid, with an aromatic phenol derivative, for example, by reacting phosphorus oxychloride with phenols, removing the catalyst by neutralization washing, and hydrolyzing impurities by distillation and washing. Except for
Phosphate ester which is commercialized through purification such as decolorization and dehydration; after ring-opening polymerization of a lower alcohol and an alkylene oxide such as ethylene oxide or propylene oxide, or after alkali metalization of a monoether type terminal hydroxyl group , A polyglycol reacted with an alkyl halide; and the like.

Further, other oily substances other than those described above include
For example, an organochlorosilane represented by the general formula “R ₃ SiCl” or “R ₂ SiCl ₂ ” (where R represents a hydrocarbon group) as an intermediate by reacting a chlorinated hydrocarbon with silicon. And ((R ₃ Si) obtained by hydrolyzing the organochlorosilane.
_A silicone synthetic oil obtained by adjusting the ratio of ₂ O ”or“ (R ₂ SiO) _n ”( _{where n} represents a natural number) and then polymerizing in the presence of an acid catalyst or an alkali catalyst; A polyphenol synthesized by reacting an aromatic halide with an alkali metal salt of a phenol using a copper-based catalyst;

Further, other oily substances other than those described above include
For example, an alkyl phenyl ether obtained by a Friedel-Crafts reaction between an α-olefin and a phenyl ether using a catalyst such as aluminum chloride; low-polymerization of ethylene trifluoride chloride or hydrogen constituting polyglycol Fluorine-based polyether obtained by fluorine substitution;

As the oily substance, in addition to the various compounds exemplified above, conventionally known organic solvents can be used. Examples of the organic solvent include alcohols such as butanol and propanol; ketones such as methyl ethyl ketone and methyl butyl ketone; saturated aliphatic hydrocarbons such as octane and decane; aromatic hydrocarbons such as benzene, toluene and xylene. Glycol derivatives such as ethyl glycol and butyl glycol; and organic chlorinated products such as chloromethylene and chlorobenzene.

In the present invention, as the oily substance, if necessary, only one kind may be used, or two or more kinds may be used in combination. In the lubricant according to the present invention,
The metal oxide particle composite is more preferably mixed or dispersed in water or an oily substance such as silicone oil or polybutene, and particularly preferably dispersed and used. When the metal oxide particle composite is dispersed in a liquid substance such as water or an oily substance, the metal oxide particle composite is uniformly dispersed in the liquid substance with an average particle diameter of 1 μm or less without aggregation. Therefore, the lubricant can exhibit lubricating properties such as excellent extreme pressure properties, abrasion resistance, and friction resistance.

When the metal oxide particle composite is used without being dispersed in a liquid substance, extreme pressure resistance, abrasion resistance,
There is a possibility that a lubricant excellent in lubrication properties such as friction resistance cannot be obtained. Further, when the metal oxide particle composite is not dispersed in the liquid substance with an average particle diameter of 1 μm or less, a lubricant having excellent friction resistance may not be obtained.

The liquid material is particularly preferably a solvent or a dispersion medium for treating the surface of metal oxide particles with an organic substance. When the liquid substance is a liquid substance other than a solvent or a dispersion medium when the surface of the metal oxide particles is treated with an organic substance, the process in the production of the lubricant may be complicated.

When the metal oxide particle composite according to the present invention is used by being mixed or dispersed in a liquid substance, the amount of the metal oxide particle composite used is not particularly limited. , 0.1% to 80% by weight, more preferably 1% to 50% by weight. If the amount of the metal oxide particle composite used is less than 0.1% by weight, a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance may not be obtained. There is. On the other hand, when the use amount of the metal oxide particle composite exceeds 80% by weight, a lubricant excellent in friction resistance may not be obtained.

Further, in the lubricant according to the present invention,
The metal oxide particle composite is preferably used by being mixed or dispersed in a semi-solid substance or a solid substance, and more preferably dispersed and used. Examples of the semi-solid substance or solid substance that can be used in the present invention include a wax-like substance, a grease-like substance, and a synthetic resin.

Examples of the waxy substance include saturated aliphatics, unsaturated aliphatics, esters, fatty acid amides, hardened oils, hardened fatty acids, metal soaps, sodium alkylbenzene sulfonates, alcohol sulfates , Alkylmethyl taurides, polyoxyethylene alkylphenol ethers, polyethyleneoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyethylene glycols, polyethylene waxes, paraffin hydrocarbon waxes, carnauba wax, Candy wax,
Examples include microcrystalline waxes and α-olefins.

Examples of the grease-like substance include mineral oil grease, high viscosity mineral oil grease, diester grease, polyol ester grease, poly-α-olefin grease, phenyl ether grease, silicone grease, and Fluorine grease and the like can be mentioned.

As the above synthetic resin, a thermoplastic resin, a thermosetting resin, a secondary processing resin, a natural polymer, a so-called medium molecular weight polymer or the like can be used. Specifically, as the thermoplastic resin, for example, an ionomer resin, AA
S (Acrylonitrile-Acrylic-Styrene) resin, AES (Acr
ylonitrile-EPDM-Styrene) resin, AS (Acrylonitrile-S
tyrene) resin, ABS (Acrylonitrile-Butadiene-Styre
ne) Resin, ABS / PVC resin, ACS (Acrylonitri
le-Chlorinated polyethylene-Styrene) resin, MBS (M
(ethyl methacrylate-Butadiene-Styrene) resin, ethylene-vinyl chloride copolymer resin, ethylene-vinyl acetate copolymer, modified ethylene-vinyl acetate copolymer, ethylene-vinyl acetate copolymer resin, ethylene-vinyl acetate-vinyl chloride graft polymer resin, chloride Vinylidene resin, vinylidene chloride latex, vinyl chloride resin, chlorinated vinyl chloride resin, chlorinated polyethylene, chlorinated polypropylene, coumarone resin, ketone resin, vinyl acetate resin, phenoxy resin, butadiene resin, fluororesin, polyvinylpolypropionate, polyacetal , Polyamide, polyamideimide, polyarylate, thermoplastic polyimide, polyetherimide, polyetherketone, polyethylene,
Polyethylene oxide, polyethylene terephthalate, polycarbonate, polystyrene, polysulfone,
Poly-p-methylstyrene, polyallylamine, polyvinyl alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl formal, polyphenylene ether (polyphenylene oxide), modified polyphenylene ether (modified polyphenylene oxide), polyphenylene sulfide, polybutylene terephthalate, polypropylene, polymethylpentene , Methacrylic resin,
And a liquid crystal polymer.

Examples of the secondary processing resin include an ion exchange resin, a photosensitive resin, and a carboxyvinyl polymer. Examples of the natural polymer include cellulose acetate, a cellulose derivative, an isobutylene / maleic anhydride copolymer resin, polyglutamic acid, and polyterpene.

Examples of the medium molecular weight polymer include low molecular weight polyethylene, low molecular weight polypropylene, oligoester acrylate, polybutene, liquid polybutadiene, liquid rubber, petroleum resin, DCPD resin, low molecular weight polystyrene, polyhydroxy polyolefin, and α.
-Methylstyrene oligomer and the like. Examples of the liquid rubber include liquid BR (Butadiene Rub).
ber), liquid SBR (Styrene Butadiene Rubber), liquid N
Examples thereof include BR (Nitrile Butadiene Rubber), liquid polychloroprene (CR), liquid polysulfide (thiochol), liquid polyisoprene, liquid polyisobutylene, and liquid butyl rubber.

When the metal oxide particle composite according to the present invention is used by being mixed or dispersed in a semi-solid substance or a solid substance, the amount of the metal oxide particle composite used is as follows:
Although not particularly limited, it is more preferably in the range of 0.1% by weight to 80% by weight, and more preferably in the range of 1% by weight to 50% by weight, based on the semi-solid substance or solid substance. Is more preferable. If the amount of the metal oxide particle composite used is less than 0.1% by weight, it may not be possible to obtain a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance and friction resistance. is there. On the other hand, when the use amount of the metal oxide particle composite exceeds 80% by weight,
There is a possibility that a lubricant excellent in friction resistance cannot be obtained.

As described above, in the lubricant according to the present invention, the metal oxide particle composite is used alone or, if necessary, mixed or dispersed in a liquid substance, a semi-solid substance, a solid substance, or the like. Among them, metal oxide particle composites can be used as liquid substances, semi-solid substances,
It is particularly preferable to use it by dispersing it in a solid substance or the like.

Next, a method for producing the metal oxide particle composite according to the present invention will be described. However, the method is not limited to the following method as long as the effects of the present invention are not impaired. Examples of the production method include (1) a method of introducing metal oxide particles and an organic substance into a solvent or a dispersion medium and stirring the mixture at a predetermined temperature to treat the surface of the metal oxide particles with the organic substance (method ( 1)), (2) a method of applying a predetermined solvent dissolving an organic substance to the metal oxide particles, and then drying (method (2)), (3) mixing the metal oxide particles and the organic substance,
A heating method (method (3)) and the like can be mentioned. Among the above-mentioned production methods, the above-mentioned method (1) is preferable because the metal oxide particles can be uniformly coated with the organic substance.

The solvent or dispersion medium used in the method (1) may be water alone or an oily substance alone, or may be a mixture of water and an oily substance. When the liquid substance is a mixture of water and an oily substance, the oily substance may be dissolved in water,
It may be dispersed or emulsified. Or conversely, water may be dissolved in the oily substance, or may be dispersed or emulsified. As the solvent or dispersion medium, for example, the liquid substances exemplified above can be used.

The organic substance is preferably an organic substance having a group reactive with the metal oxide particles. The metal oxide particle composite is, for example, a metal oxide particle and a metal oxide particle. It is preferable that the metal oxide particles are treated with an organic material having a reactive group for the metal oxide particles by reacting the material particles with an organic material having a reactive group.

The above-mentioned surface treatment, that is, the reaction between the metal oxide particles and the organic substance can be carried out at room temperature, but can also be carried out by heating or removing heat, preferably at 0 ° C. to 350 ° C. When the organic substance evaporates within the reaction temperature, the reaction can be carried out while refluxing.

The metal oxide particle composite solution obtained by the above reaction can be used as a lubricant by further adding the above-mentioned liquid substance. In some cases, the metal oxide particle composite solution is dried. Alternatively, the lubricant can be dispersed in a liquid material.

When the lubricant according to the present invention is obtained by mixing or dispersing each of the above-described metal oxide particle composites in a liquid substance, that is, when the lubricant is formed by mixing the metal oxide particle composite with the liquid substance. When it contains, the liquid substance is preferably the same as the solvent or dispersion medium used for the surface treatment of the metal oxide particles.

That is, when the lubricant according to the present invention is obtained by mixing or dispersing each of the above-described metal oxide particle composites in a liquid substance, the solvent or dispersion medium used in the method (1) is used as it is. It is used as a liquid material for mixing or dispersing the respective metal oxide particle composites in a liquid material.

[0092] In this case, the metal oxide particles are contained in an amount of 1 g to 1 liter per one liter of the liquid material, ie, the solvent or the dispersion medium.
It is preferably introduced (blended) at a rate of 5,000 g, and more preferably at a rate of 10 g to 1,000 g. If the amount of the metal oxide particles used is less than 1 g, a step of removing or concentrating these liquid substances may be required. On the other hand, the amount of metal oxide particles used is 5,
If it exceeds 000 g, the viscosity of the reaction contents may increase, and stirring may not be possible.

The amount of the organic substance used for the metal oxide particles may be set so that the content of the organic substance in the metal oxide particle composite becomes a predetermined value.
In order to use the solvent or dispersion medium used in the method (1) as a liquid substance for mixing or dispersing the metal oxide particle composite in the liquid substance, the following ratio is used, for example.

For example, when the metal oxide particle composite is an alumina particle composite, the organic substance is preferably used in a ratio of 0.01 g to 100 g per 100 g of alumina particles, and 0.1 g to 40 g. Is more preferably used. If the amount of the organic substance used is less than 0.01 g, a step of removing or concentrating the liquid substance may be required. On the other hand, if the amount of the organic substance used exceeds 100 g, the viscosity of the reaction contents may increase, and stirring may not be possible.

When the metal oxide particle composite is a zirconia particle composite, the organic substance is preferably used in a ratio of 0.01 g to 100 g per 100 g of zirconia particles, and 0.1 g to 40 g. Is more preferably used. If the amount of the organic substance used is less than 0.01 g, a step of removing or concentrating the liquid substance may be required. On the other hand, if the amount of the organic substance used exceeds 100 g, the viscosity of the reaction contents may increase, and stirring may not be possible.

When the metal oxide particle composite is a silica particle composite, the method for producing the silica particle composite includes, for example, one molecule in a dispersion in which spherical silica fine particles are dispersed. And at least one polysiloxane group per group, and at least one “Si—OR ¹ group” (R ¹ is at least one selected from the group consisting of a hydrogen atom, an alkyl group, and an acyl group) a kind of group, the alkyl and acyl groups a group which may be substituted; when R ¹ are a plurality in one molecule, a plurality of R ¹ may be the being the same or different) A method of obtaining a silica particle composite by hydrolyzing and condensing an organic polymer (P) containing (hereinafter, referred to as production method A) is suitably used as the method (1) described above.

The spherical silica fine particles used in the production method A are not particularly limited as long as they have a spherical shape. In the present invention, the term “spherical” refers to a true spherical shape or a shape close to a spherical shape such as an egg. Indicates something. Particle aspect ratio is 0.7 ~
A ratio of 1.5 is preferable because the performance of the finally obtained lubricant is further improved.

[0098] The particle diameter of the spherical silica fine particles is not particularly limited, and any particle diameter can be used.
It is preferable to use spherical silica fine particles of 5 nm to 1 μm.

The method for producing the spherical silica fine particles is not particularly limited. For example, any one of a melting method, a melt spraying method, a precipitation method, an alkoxide method, a suspension method, an interfacial polymerization method, a neutralization method and the like can be used. It may be obtained by a method. Among them, spherical silica fine particles obtained by an alkoxide method using tetramethoxysilane or the like as a raw material are preferable because a large number of alkoxy groups which react easily with the organic polymer (P) described later are present on the surface of the spherical silica fine particles.

The particle size distribution of the spherical silica fine particles is not particularly limited, but the variation coefficient of the particle size is 50%.
It is preferably at most 40%, more preferably at most 40%, most preferably at most 30%. When a silica particle composite obtained using spherical silica fine particles having a wide variation in particle diameter having a coefficient of variation exceeding 50% is used as a lubricant, the performance of the lubricant deteriorates.

Although the spherical silica fine particles may contain an inorganic oxide other than silica, the content of the other inorganic oxides is limited to the total amount of the spherical silica fine particles because of the availability of the spherical silica fine particles. It is preferably at most 20% by weight, more preferably at most 10% by weight, most preferably at most 5% by weight.

The spherical silica fine particles may have an organic group or a hydroxyl group. The organic group is at least one group selected from the group consisting of an optionally substituted alkyl group having 20 or less carbon atoms, a cycloalkyl group, an aryl group, and an aralkyl group. The content of the organic group in the spherical silica fine particles is preferably 10% by weight or less, more preferably 5% by weight or less, and more preferably 2% by weight of the whole spherical silica fine particles.
The following are most preferred.

The organic polymer (P) used in the above-mentioned production method A comprises an organic chain and a polysiloxane group.
It has a structure having at least one polysiloxane group per molecule and containing at least one “Si—OR ¹ group” in the polysiloxane group. The structure of the organic chain is not particularly limited. The bonding form between the polysiloxane group and the organic chain is “Si—C” bonding. Here, when the bonding form is a “Si—O—C” bond or the like, this bond may be easily broken by hydrolysis, exchange reaction, or the like.

The structure of the organic polymer (P) is not particularly limited as long as it is soluble in an organic solvent or water described later. For example, the structure is obtained by grafting a polysiloxane group to an organic chain. A polymer, a polymer obtained by bonding a polysiloxane group to at least one of the organic chain terminals, or a polysiloxane group as a core and a plurality of linear or branched organic chains (a plurality of (Organic chains may be the same or different from each other).

The organic chain is a portion other than the polysiloxane group in the organic polymer (P). The element constituting the main chain in the organic chain is mainly composed of carbon, and its content accounts for 50 mol% to 100 mol% of the whole organic chain, and the rest is nitrogen, oxygen, sulfur, silicon, phosphorus, or the like. And the like are preferred because they can be easily obtained. Specific examples of the resin constituting the organic chain include (meth)
Acrylic resin, polystyrene, polyvinyl acetate, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, polyesters such as polyethylene terephthalate, and their copolymers, and by modifying some of these polymers The resulting modified resin is exemplified. Above all, the resin that constitutes the organic chain is
At least one resin selected from the group consisting of (meth) acrylic resin and polyester is preferable because the organic polymer (P) can be easily produced.

The “OR ¹ group” in the “Si-OR ¹ group”
Is a functional group capable of hydrolysis and / or condensation,
The number is at least one per molecule of the organic polymer (P). The number of “OR ¹ groups” is more preferably 5 or more on average, and even more preferably 20 or more. "O
As the number of “R ¹ groups” increases, the number of reaction points when hydrolyzing and condensing the organic polymer (P) increases, so that the bond with the spherical silica fine particles can be further strengthened.

The “R ¹ group” is at least one group selected from the group consisting of a hydrogen atom, an alkyl group and an acyl group, and the alkyl group and the acyl group are optionally substituted groups. The number of carbon atoms of the alkyl group and the acyl group is not particularly limited.
^{In order that} the hydrolysis rate of “ ^one group” is high and the silica particle composite is easily and efficiently produced, it is more preferably 1 to 5. As the alkyl group, specifically, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a t-butyl group,
And a pentyl group. Specific examples of the acyl group include an acetyl group and a propionyl group. As the substituted alkyl group and acyl group, at least one hydrogen atom of the alkyl group and the acyl group is, for example, an alkoxy group such as a methoxy group and an ethoxy group; an acyl group such as an acetyl group and a propionyl group;
And an alkyl group and an acyl group substituted with a halogen atom such as a chlorine atom and a bromine atom; "R
When a plurality of “ ^one group” is present in one molecule, a plurality of R ¹ may be the same or different. Above all, "R ¹
The “group” is more preferably at least one group selected from the group consisting of a hydrogen atom, a methyl group and an ethyl group, and most preferably a methyl group.

The polysiloxane group has at least one “Si—OR ¹ group” in which the “OR ¹ group” is bonded to a silicon atom,
When two or more silicon atoms have a polysiloxane bond (Si-O
—Si) is a group linked in a straight or branched chain by —Si). Although the number of silicon atoms in the polysiloxane group is not particularly limited,
In terms of being able to contain a large number of "R ¹ groups", on average, 3 or more per polysiloxane group are more preferable,
7 or more are more preferred, and 11 or more are most preferred. Specific examples of such a polysiloxane group include, for example, a polymethylmethoxysiloxane group, a polyethylmethoxysiloxane group, a polymethylethoxysiloxane group, a polyethylethoxysiloxane group, a polyphenylmethoxysiloxane group, and a polyphenylethoxysiloxane. And the like.

Further, a silicon atom in the polysiloxane group is bonded to an organic chain and a polysiloxane bond (Si
It is preferable that other than —O—Si) be bonded only to “OR ¹ group”. In such a case, the ionicity of the silicon atom is further increased, and as a result, the rate of hydrolysis / condensation of the “OR ¹ group” is increased, and the silica particle composite can be easily and efficiently produced. At the same time, the number of reaction points in the organic polymer (P) increases, so that excellent affinity for a matrix resin or the like can be imparted to the silica particle composite. Specific examples of such a polysiloxane group include a polydimethoxysiloxane group, a polydiethoxysiloxane group, a polydiisopropoxysiloxane group, and a poly-n-butoxysiloxane group.

The number average molecular weight (M) of the organic polymer (P)
n) is not particularly limited, but 200,00
It is more preferably 0 or less, and further preferably 50,000 or less. The organic polymer (P) can be produced by a conventionally known method. For example, a silane coupling agent having a double bond group or a mercapto group is combined with a silane compound (H) and / or a derivative thereof described below. After hydrolysis / condensation, a method of radically (co) polymerizing a radically polymerizable monomer in the presence of the obtained co-hydrolysate or condensate (hereinafter, referred to as polymerizable polysiloxane), and the like, are particularly limited. It is not something to be done.

Specific examples of the silane compound (H) include acyloxysilane compounds such as methyltriacetoxysilane, dimethyldiacetoxysilane, trimethylacetoxysilane, and tetraacetoxysilane; tetramethoxysilane, tetraethoxysilane, Tetraisopropoxysilane, tetrabutoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, trimethylmethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, dimethoxydiethoxysilane And the like, but are not particularly limited. Further, as the derivative of the silane compound (H),
Specific examples include a hydrolyzate and a condensate of the silane compound (H).

Among the silane compounds (H) exemplified above, the alkoxysilane compounds are particularly preferable because they are easily available as raw materials. In addition, when the silane compound (H) and its derivative are tetraalkoxysilane compounds and their derivatives, the rate of hydrolysis / condensation is increased, and the surface of the spherical silica fine particles is easily and efficiently compounded to form a silica particle composite. It is further preferred that the body can be manufactured.

In the above-mentioned production method A, a silica particle composite is obtained by compounding the spherical silica fine particles in a dispersion in which the spherical silica fine particles are dispersed. The dispersion liquid in which the spherical silica fine particles are dispersed may include water and an organic solvent described below as necessary. The composition of the dispersion is not particularly limited as long as the composition dissolves the organic polymer (P).

Specific examples of the above organic solvent include aromatic hydrocarbons such as benzene, toluene and xylene; methyl acetate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, and ethylene glycol monomethyl ether acetate. Acetate esters such as ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and propylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; Ethers such as tetrahydrofuran, dioxane, diethyl ether and di-n-butyl ether; methyl alcohol, ethyl alcohol, isopropyl alcohol, n- Alcohols such as tyl alcohol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monobutyl ether; methylene chloride, chloroform, etc. Halogenated hydrocarbons; and the like, but are not particularly limited thereto. These organic solvents may be used alone or in combination of two or more. Among the organic solvents exemplified above, alcohols, ketones, and ethers are more preferable because they form a uniform mixed solution when mixed with water.

The catalyst used for hydrolyzing and condensing the organic polymer (P) is preferably a basic catalyst. The basic catalyst can further increase the conversion rate of “Si—OR ¹ group” in the organic polymer (P), and can bind the organic polymer (P) more firmly to the surface of the spherical silica fine particles.

Specific examples of the basic catalyst include, for example, ammonia; organic amine compounds such as triethylamine and tripropylamine; sodium methoxide, sodium ethoxide, potassium methoxide, potassium ethoxide and potassium-t-butoxide. And alkali metal compounds such as sodium hydroxide and potassium hydroxide; basic ion exchange resins; and the like, but are not particularly limited thereto. One of these basic catalysts may be used alone, or two or more thereof may be used in combination. Among the basic catalysts exemplified above, ammonia and organic amine compounds are more preferable because they are easily removed after complexing.

The composition of the dispersion, which is the raw material for hydrolysis and condensation, that is, the mixing ratio of the spherical silica fine particles, the organic polymer (P), water, the organic solvent, the catalyst, and the like is not particularly limited. However, the following compounding ratio is more preferable. That is, the compounding ratio of the spherical silica fine particles is preferably in the range of 0.1% by weight to 30% by weight based on the total amount of the dispersion so that the self-condensation between the organic polymers (P) can be further prevented. Preferably, it is more preferably in the range of 0.5% to 25% by weight, and most preferably in the range of 1.0% to 20% by weight. The compounding ratio of the organic polymer (P) is set to 0.1 with respect to the total amount of the dispersion so that self-condensation between the organic polymers (P) can be further prevented.
The content is more preferably in the range of 0.01% by weight to 60% by weight.
The content is more preferably in the range of 1% by weight to 50% by weight,
Most preferably, it is in the range of 2% to 20% by weight. The weight ratio of the spherical silica fine particles to the organic polymer (P) is not particularly limited, but the content of the organic polymer (P) in the obtained silica particle composite is 5% by weight to 80%.
More preferably, the weight ratio is within the range of weight%.

The mixing ratio of the organic solvent is 99.9 with respect to the total amount of the dispersion so that the spherical silica fine particles can be uniformly dispersed and the organic polymer (P) can be sufficiently dissolved. % By weight or less, more preferably from 20% by weight to 99% by weight, and more preferably 40% by weight.
Most preferred is in the range of ~ 99% by weight. The mixing ratio of the catalyst is 0.01% by weight to 20% by weight based on the total amount of the dispersion so that “Si—OR ¹ group” in the organic polymer (P) can be sufficiently hydrolyzed and condensed. Is more preferably in the range of 0.05% by weight to 10% by weight, and most preferably in the range of 0.1% by weight to 5% by weight.

The mixing ratio of water may be any ratio at which the organic polymer (P) can be hydrolyzed and condensed to easily and efficiently compound the surface of the spherical silica fine particles to produce a silica particle composite. Although not particularly limited, the larger the mixing ratio of water, the more easily the organic polymer (P) is hydrolyzed and condensed. Therefore, the mixing ratio of water is, for example, “Si-OR” in the organic polymer (P).
^The molar ratio is more preferably 0.1 or more, more preferably 2.0 or more, based on ¹ group,
Most preferably, it is 3.0 or more. However, when the organic polymer (P) is insoluble in water, the mixing ratio of water is preferably 50% by weight or less, more preferably 30% by weight or less, and more preferably 15% by weight, based on the total amount of the dispersion. %
The following are most preferred.

The hydrolysis and condensation of the organic polymer (P)
This is done by stirring the dispersion. The reaction temperature is
It is preferably in the range of 0 ° C to 100 ° C, more preferably in the range of 0 ° C to 70 ° C. The reaction time may be set in accordance with the composition of the dispersion, the reaction temperature, and the like, and is not particularly limited, but may be about 5 minutes to 100 hours.

The method of preparing the dispersion, that is, the method of mixing the spherical silica fine particles, the organic polymer (P), water, the organic solvent, the catalyst and the like is not particularly limited. Spherical silica fine particles, organic polymer (P), water, organic solvent,
And the catalyst or the like may be mixed alone or simultaneously at the same time, or may be mixed together, or alternatively, after preparing a mixture of several components in advance, the remaining components may be mixed with the mixture. Further, after preparing a plurality of mixtures in which some components are mixed in advance, these mixtures may be mixed. In particular, water may be previously mixed with a dispersion liquid in which spherical silica fine particles are dispersed, or may be mixed with the dispersion liquid together with the organic polymer (P), or may be separately dispersed with the organic polymer (P). The organic polymer (P) may be mixed with the dispersion, and then the organic polymer (P) may be dissolved in the dispersion and then mixed with the dispersion.

The by-products and the catalyst produced by the hydrolysis and condensation of the organic polymer (P) and the catalyst can be easily removed by performing operations such as filtration and distillation, if necessary. .

Further, as a method for producing a silica particle composite, at least one polysiloxane group is provided per molecule, and at least one polysiloxane group is contained in the polysiloxane group.
"Si-OR ¹ groups" (R ¹ is at least one group selected from the group consisting of a hydrogen atom, an alkyl group and an acyl group, wherein the alkyl group and the acyl group may be substituted; When a plurality of R ¹ are present in one molecule, the plurality of R ¹ may be the same or different from each other), the organic polymer (P) containing the organic polymer (P) alone or a hydrolyzable silane A method of obtaining a silica particle composite by hydrolysis and condensation together with the compound (H) (hereinafter referred to as Production Method B) is also suitably used.

In the production method B, the organic polymer (P) can be hydrolyzed and condensed with the organic polymer (P) alone to obtain a silica particle composite. Further, the organic polymer (P) and the above-mentioned silane compound (H)
Can be hydrolyzed and condensed to obtain a silica particle composite. When the tetraalkoxysilane compound and its derivative are used among the silane compounds (H) described above,
The rate of hydrolysis / condensation is further increased, and a silica particle composite having a stronger skeleton can be produced, whereby high lubrication performance can be exhibited.

The method of hydrolysis / condensation in the above-mentioned production method B is not particularly limited, but is preferably carried out in a solution. The solution is a solution containing the water and the organic solvent described above. The composition of the solution is not particularly limited. The catalyst used for the hydrolysis and condensation in the production method B is preferably the above-mentioned basic catalyst.

Although the composition of the above solution is not particularly limited, as described above, the content of the organic polymer (P) in the obtained silica particle composite is 5% by weight to 8% by weight.
More preferably, the weight ratio is within the range of 0% by weight.

The amount of water used for hydrolysis and condensation is as follows:
The amount is not particularly limited as long as the organic polymer (P) and the silane compound (H) can be co-hydrolyzed and condensed to produce a silica particle composite. The larger the amount, the more the cohydrolysis / condensation of the organic polymer (P) and the silane compound (H) proceeds sufficiently, so that a silica particle composite having a stronger skeleton can be produced.

The reaction temperature and the reaction time in the above-mentioned production method B may be set in the same manner as in the above-mentioned production method A. The method for preparing the solution, that is, the method for mixing the organic polymer (P), the silane compound (H), water, the organic solvent, the catalyst, and the like is not particularly limited. The organic polymer (P) or a solution thereof, and the silane compound (H) or a solution thereof may be mixed with each other in advance and then mixed with a solution containing water, or separately mixed with a solution containing water. You may. When mixing the organic polymer (P) or its solution, and the silane compound (H) or its solution with a solution containing water, they may be mixed at once, or may be mixed separately. You may mix continuously. Alternatively, a solution containing water can be mixed with the organic polymer (P) or its solution, or the silane compound (H) or its solution. The catalyst may be previously mixed with at least one of the organic polymer (P), the silane compound (H), water, and the organic solvent.
There is no particular limitation.

Organic polymer (P) and silane compound (H)
The by-products and the catalyst produced by the co-hydrolysis and condensation with the catalyst can be easily removed by performing operations such as filtration and distillation, if necessary.

The silica particle composite obtained by the above-mentioned production method A, production method B or the like can be mixed or dispersed in the above-mentioned liquid substance, semi-solid substance or solid substance by any method. When the silica particle composite contains an organic solvent and water, the removal of the organic solvent and water involves mixing the silica particle composite with a liquid substance, a semi-solid substance, and a solid substance. It may be performed before or after mixing.

As described above, the lubricant according to the present invention
It comprises a metal oxide particle composite surface-treated with an organic substance. According to the above configuration, the metal oxide particle composite has excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance with an average particle diameter of, for example, 1 μm or less. Therefore, it is possible to provide a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance. The metal oxide particle composites may be used alone or in combination as appropriate.

The lubricant according to the present invention may, if necessary, include, for example, a polyacrylate or a partial hydrolyzate thereof, a polymethacrylate or a partial hydrolyzate thereof, polyvinyl acetate or a hydrolyzate thereof. Stuff,
Organic polymer such as polyvinylpyrrolidone, a copolymer of styrene and maleic anhydride or a half ester thereof, and the like can be blended as a film-forming component.

The lubricant according to the present invention has excellent lubricating properties such as extreme pressure resistance, friction resistance and abrasion resistance, and also has excellent dispersion stability of the metal oxide particle composite in various media such as liquid substances. ing. Therefore, the lubricant can be suitably used for various equipment such as ceramics and metal, specifically, for example, various machines used outdoors,
It can be suitably used in various applications and fields such as various types of bearings provided in printing machines, stranded wire machines, electric devices, automobile parts and the like.

[0134]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Various properties of the lubricant were evaluated by the following methods.

(A) Dispersion stability A test tube having a height of 150 mm and a diameter of 15 mm was filled with a lubricant to a height of 100 mm from the bottom of the test tube. Then, after leaving the test tube at 50 ° C. for 10 days, a metal oxide particle composite in a lubricant (a metal oxide particle composite corresponding to the metal oxide particle composite used in each example; for example, Corresponding silica particle composite, alumina particle composite,
The dispersion stability of the zirconia particle composite or a combination thereof) was visually confirmed and evaluated. That is, after leaving for 10 days after filling, the case where the metal particle composite does not settle and the lubricant is kept in a uniformly dispersed state is evaluated as “good”, and the metal particle composite is settled and lubricated. The case where the agent did not maintain a uniform dispersion state was evaluated as “poor”.

(B) Friction Resistance The friction resistance was evaluated by performing a so-called pendulum II type friction test. That is, the friction resistance was measured using a pendulum type oil friction tester (manufactured by Shinko Zoki Co., Ltd.) as a tester, the initial amplitude was 0.5 radian, the weight of the pendulum vertical weight was 40 g, and the pendulum horizontal weight was Under standard test conditions where the weight is 80 g, the mounting position of the pendulum vertical bell is 100 mm from the fulcrum, and the mounting position of the pendulum horizontal bell is 340 mm from the fulcrum, the pendulum angle when the swing angle of the pendulum coincides five times is determined. The deflection angle was read and evaluated by calculating the dynamic friction coefficient from the deflection angle. Therefore, it can be evaluated that the smaller the dynamic friction coefficient of the lubricant, the better the friction resistance.

Example 1 In a 300 ml four-necked flask equipped with a stirrer, a reflux condenser and a thermometer, 144.5 g of tetramethoxysilane, 23.6 g of γ-methacryloxypropyltrimethoxysilane and 19 g of water were placed. , 30.0 g of methyl alcohol, and 5.0 g of Amberlyst 15 (trade name; a cation exchange resin manufactured by Rohm and Haas Japan KK). Then, the contents of the flask were reacted by stirring at 65 ° C. for 2 hours.

After the obtained reaction mixture was cooled to room temperature, the reflux condenser was removed, and a distillation column equipped with a Liebig condenser, a receiver and a decompression device was used instead. Thereafter, the temperature of the reaction mixture was raised to 80 ° C. over 2 hours under normal pressure, kept at the same temperature until methyl alcohol did not evaporate, and further reacted. Then, the inside of the flask is 200
After reducing the pressure to mmHg, the reaction mixture was heated to 90 ° C.
The temperature was maintained at the same temperature until methyl alcohol did not evaporate, and further reacted.

After cooling the contents of the flask to room temperature,
Amber list 15 was filtered off. As a result, a polymerizable polysiloxane having a number average molecular weight (Mn) of 1,800 was obtained in a liquid state.

Next, a stirrer, a dropping funnel, a reflux condenser,
In a 500 ml four-necked flask equipped with a nitrogen gas inlet tube and a thermometer, 260 g of methyl alcohol was charged,
The mixture was heated to 65 ° C. while stirring under a stream of nitrogen gas. On the other hand, the above polymerizable polysiloxane 14 was added to the dropping funnel.
g, 35 g of methyl methacrylate, 91 g of acrylic acid, and 4 g of 2,2'-azobis- (2,4-dimethylvaleronitrile). Then, the above mixture was added to methyl alcohol in the flask for 2 hours.
It was dropped over time.

After completion of the dropwise addition, the contents of the flask were stirred at 65 ° C. for 1 hour to copolymerize. After that, the contents
2'-azobis- (2,4-dimethylvaleronitrile)
While adding 0.3 g twice at 30 minute intervals, 2
The mixture was stirred for another hour and further copolymerized.

As a result, an organic polymer (P-1) having a number average molecular weight of 9,000 was obtained in the form of a methyl alcohol solution. The organic polymer (P-1) contains silicon. The percentage of solids in the methyl alcohol solution was 35.0%.

Next, 280 g of methyl alcohol was charged into a 1-L four-necked flask equipped with a stirrer, two dropping funnels, a Liebig condenser, and a thermometer, and the mixture was maintained at 20 ° C. with stirring. To one dropping funnel a, 7 g of a methyl alcohol solution of the organic polymer (P-1), 18 g of tetramethoxysilane, and 5 g of methyl alcohol 5
A mixed solution obtained by mixing 0 g was charged. Further, 56 g of water and 25% by weight of aqueous ammonia 17 were added to the other dropping funnel b.
g and 17 g of methyl alcohol. Then, the above two types of mixed liquids were dropped into methyl alcohol in the flask over 1 hour.

After the addition was completed, the contents of the flask were stirred at 20 ° C. for 30 minutes. In the meantime, the dropping funnel a
Then, a mixed solution obtained by mixing 26 g of a methyl alcohol solution of the organic polymer (P-1), 53 g of tetramethoxysilane, and 150 g of methyl alcohol was charged.
Further, a mixed solution obtained by mixing 56 g of water, 20 g of 25% by weight ammonia water, and 75 g of methyl alcohol was charged into the dropping funnel b. Next, the above two kinds of mixed liquids were dropped into the contents of the flask over 1 hour.

After completion of the dropwise addition, the contents of the flask were stirred at 20 ° C. for 2 hours. Thereafter, the content was gradually heated to 100 ° C., and ammonia and methyl alcohol were distilled off and water was added to concentrate the content until the solid content became 15%. Thereby, the content of the silica particle composite dispersed in water (liquid substance), that is,
A lubricant (1) according to the present invention was obtained. The average particle diameter of the silica particle composite was 23 nm, and the coefficient of variation was 18%. The methoxy group content in the silica particle composite was 0.05 mmol / g.

The dispersion stability and friction resistance of the obtained lubricant (1) were evaluated by the above-mentioned methods. As a result, the dispersion stability of the lubricant (1) was “good”. The dynamic friction coefficient was 0.18, and the lubricant (1) was excellent in friction resistance.

Comparative Example 1 A comparative lubricant (1) was obtained by mixing 10 parts by weight of silica particles and 90 parts by weight of ion-exchanged water for 8 hours using a ball mill. That is, a comparative lubricant (1) was prepared using silica particles that had not been surface-treated with an organic polymer. The dispersion stability of the obtained comparative lubricant (1) was evaluated by the above method. As a result, the dispersion stability of the comparative lubricant (1) was “poor”.

[Comparative Example 2] Deionized water was used as a comparative lubricant (2). The friction resistance of the comparative lubricant (2) was evaluated by the above method. As a result, the dynamic friction coefficient of the comparative lubricant (2) was 0.34, and the comparative lubricant (2) was inferior in friction resistance.

As is clear from the comparison between the result of Example 1 and the result of Comparative Example 1, the lubricant according to the present invention comprises:
Even after standing for 10 days, the silica particle composite maintains a uniform dispersion state without sedimentation, whereas the comparative lubricant cannot maintain a uniform dispersion state due to the silica particle sedimentation. I understand. Further, as is clear from the comparison between the result of Example 1 and the result of Comparative Example 2, it is understood that the lubricant according to the present invention has excellent friction resistance.

Example 2 An aqueous dispersion of alumina particles (solids concentration: 9.3% by weight) was placed in a 500 ml three-necked flask equipped with a stirrer, a reflux condenser, and a thermometer.
g, 138.7 g of ion-exchanged water, and 0.75 g of γ-aminopropyltrimethoxysilane. Then, the contents of the flask were reacted by stirring at 60 ° C. for 1 hour. Thereby, the alumina particles become γ-
An aqueous alumina particle composite dispersion having a pH of 2.87 was obtained, including the alumina particle composite surface-treated with aminopropyltrimethoxysilane.

Next, the aqueous dispersion of the alumina particle composite was cooled to room temperature, and then neutralized by dropwise addition of a 1 M aqueous sodium hydroxide solution to adjust the pH of the aqueous dispersion of the alumina particle composite to 5.94. did. As a result, a content in which the alumina particle composite was dispersed in water (liquid substance), that is, the lubricant (2) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (2) were evaluated by the above methods. As a result, the dispersion stability of the lubricant (2) was “good”. The dynamic friction coefficient was 0.12, and the lubricant (2) was excellent in friction resistance.

Example 3 In the same three-necked flask as in Example 2, 64.5 g of an aqueous dispersion of alumina particles (solid content concentration: 9.3% by weight), 235.5 g of ion-exchanged water, and γ
0.30 g of aminopropyltrimethoxysilane was charged. Then, the contents of the flask were heated at 60 ° C. for 1 hour,
The reaction was performed by stirring. Thus, an aqueous alumina particle composite dispersion having a pH of 3.05 and containing the alumina particle composite whose alumina particles were surface-treated with γ-aminopropyltrimethoxysilane was obtained.

Next, the aqueous dispersion of the alumina particle composite was cooled to room temperature, and the pH of the aqueous dispersion of the alumina particle composite was adjusted to 5.77 by dropping and neutralizing a 1 M aqueous sodium hydroxide solution. did. As a result, a content in which the alumina particle composite was dispersed in water (liquid substance), that is, the lubricant (3) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (3) were evaluated by the above-mentioned methods. As a result, the dispersion stability of the lubricant (3) was “good”. Further, the dynamic friction coefficient was 0.12, and the lubricant (3) was excellent in friction resistance.

Example 4 In the same three-necked flask as in Example 2, an aqueous dispersion of zirconia particles (solid content: 37.6%) was placed.
16.0 g), 284.0 g of ion-exchanged water, and 0.30 g of γ-aminopropyltrimethoxysilane. Then, the contents of the flask were reacted by stirring at 60 ° C. for 1 hour. Thereby, the zirconia particles contain the zirconia particle composite surface-treated with γ-aminopropyltrimethoxysilane, and pH =
A zirconia particle composite aqueous dispersion of 2.68 was obtained.

Next, the aqueous dispersion of the zirconia particle composite is cooled to room temperature, and the pH of the aqueous dispersion of the zirconia particle composite is adjusted to 5.92 by dropping and neutralizing a 1 M aqueous sodium hydroxide solution. did. This allows
A content in which the zirconia particle composite was dispersed in water (liquid substance), that is, the lubricant (4) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (4) were evaluated by the above methods. As a result, the dispersion stability of the lubricant (4) was “good”. Further, the dynamic friction coefficient was 0.16, and the lubricant (4) was excellent in friction resistance.

Example 5 The same reaction and operation as in Example 4 were performed, except that the amount of γ-aminopropyltrimethoxysilane was changed from 0.30 g to 0.12 g in Example 4, A zirconia particle composite aqueous dispersion having a pH of 2.47 was obtained, including a zirconia particle composite in which zirconia particles were surface-treated with γ-aminopropyltrimethoxysilane.

Next, the aqueous dispersion of the zirconia particle composite is cooled to room temperature, and the pH of the aqueous dispersion of the zirconia particle composite is adjusted to 6.02 by dropping and neutralizing a 1 M aqueous sodium hydroxide solution. did. This allows
The content in which the zirconia particle composite was dispersed in water (liquid substance), that is, the lubricant (5) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (5) were evaluated by the above method. As a result, the dispersion stability of the lubricant (5) was “good”. The dynamic friction coefficient was 0.14, and the lubricant (5) was excellent in friction resistance.

Example 6 In the same three-necked flask as in Example 2, 64.5 g of an aqueous dispersion of alumina particles (solids concentration: 9.3% by weight) and an aqueous dispersion of zirconia particles (solids concentration: 37.6%) %) 16.0 g, ion-exchanged water 219.5
g, and γ-aminopropyltrimethoxysilane 0.
30 g were charged. The contents of the flask were then
The reaction was carried out by stirring at ℃ for 1 hour. Thereby, the alumina particles and the zirconia particles each include an alumina particle composite and a zirconia particle composite each of which is surface-treated with γ-aminopropyltrimethoxysilane,
= 2.77 was obtained.

Next, the aqueous dispersion of the metal oxide composite was cooled to room temperature, and then neutralized by dropwise addition of a 1 M aqueous sodium hydroxide solution to raise the pH of the aqueous dispersion of the metal oxide composite to 5.81. Was adjusted. As a result, the alumina particle composite and the zirconia particle composite become water (liquid substance).
Was obtained, that is, the lubricant (6) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (6) were evaluated by the above methods. As a result, the dispersion stability of the lubricant (6) was “good”. The coefficient of kinetic friction was 0.14, and the lubricant (6) was excellent in friction resistance.

[Example 7] 150 g of the lubricant (3) and 150 g of the lubricant (4) obtained in the above Examples 3.4 were mixed and stirred for 1 hour to obtain an alumina particle composite and zirconia particles. The content of the composite dispersed in water (liquid substance), that is, the lubricant (7) according to the present invention was obtained.

The dispersion stability and friction resistance of the obtained lubricant (7) were evaluated by the above methods. As a result, the dispersion stability of the lubricant (7) was “good”. The dynamic friction coefficient was 0.12, and the lubricant (7) was excellent in friction resistance.

Comparative Example 3 A 1M aqueous sodium hydroxide solution was added dropwise to an aqueous dispersion of alumina particles (solid content: 9.3% by weight, pH = 2.07) to neutralize the aqueous dispersion of alumina particles. By adjusting the pH to 6, a comparative lubricant (3) was obtained. That is, a comparative lubricant (3) was prepared using alumina particles that were not surface-treated with an organic substance. The dispersion stability of the obtained comparative lubricant (3) was evaluated by the above method. As a result, the dispersion stability of the comparative lubricant (3) was “poor”.

[Comparative Example 4] Alumina particles were obtained by drying an aqueous dispersion of alumina particles using a vacuum drier and pulverizing the dispersion with a sample mill. Next, 15 g of the obtained alumina particles and 285 g of ion-exchanged water were mixed to obtain a comparative lubricant (4). That is, a comparative lubricant (4) was prepared using alumina particles that were not surface-treated with an organic substance. Obtained comparative lubricant (4)
Was evaluated by the above method. As a result, the dispersion stability of the comparative lubricant (4) was “poor”.

Comparative Example 5 A 1M aqueous solution of sodium hydroxide was added dropwise to a water dispersion of zirconia particles (solid content: 10.0% by weight, pH = 1.71) to neutralize the aqueous dispersion of zirconia particles. By adjusting the pH to 6, a comparative lubricant (5) was obtained. That is, a comparative lubricant (5) was prepared using zirconia particles that were not surface-treated with an organic substance. The dispersion stability of the obtained comparative lubricant (5) was evaluated by the above method. As a result, the dispersion stability of the comparative lubricant (5) was “poor”.

[Comparative Example 6] The aqueous dispersion of zirconia particles was dried using a vacuum dryer, and further crushed by a sample mill to obtain zirconia particles. Next, a comparative lubricant (6) was obtained by mixing 15 g of the obtained zirconia particles and 285 g of ion-exchanged water. That is, a comparative lubricant (6) was prepared using zirconia particles that were not surface-treated with an organic substance. The dispersion stability of the obtained comparative lubricant (6) was evaluated by the above method. As a result, the dispersion stability of the comparative lubricant (6) was “poor”.

The results of Examples 2 to 7 and Comparative Examples 3 to 6
As is clear from the comparison with the results, the lubricant according to the present invention maintains a uniform dispersion state without sedimentation of the alumina particle composite and the zirconia particle composite even after being left for 10 days. On the other hand, it can be seen that the comparative lubricant cannot maintain a uniform dispersion state due to sedimentation of the alumina particles or zirconia particles. Further, as is clear from the comparison between the results of Examples 2 to 7 and the results of Comparative Example 2, it can be seen that the lubricant according to the present invention has excellent friction resistance.

[0172]

As described above, the lubricant according to the first aspect of the present invention has a structure containing a metal oxide particle composite surface-treated with an organic substance.

As described above, in the lubricant according to the second aspect of the present invention, the metal oxide particle composite is obtained by treating the metal oxide particles with an organic substance having a reactive group for the metal oxide particles. It is a configuration that consists of

As described above, the lubricant according to claim 3 of the present invention is characterized in that the above-mentioned metal oxide particle composite is used in a dispersion in which silica particles are dispersed, at least one polysiloxane per molecule. A group, and at least one “Si—OR ¹ group” (R ¹ is at least one group selected from the group consisting of a hydrogen atom, an alkyl group and an acyl group; alkyl and acyl groups optionally substituted group; when R ¹ are a plurality in one molecule, an organic polymer containing a plurality of R ¹ may be the being the same or different) (P) Thus, the silica particles are obtained by treating the silica particles.

As described above, the lubricant according to the fourth aspect of the present invention is configured to further include a liquid substance.

According to the above arrangement, the metal particle composite has excellent dispersibility, and can be uniformly dispersed in, for example, a liquid substance with an average particle diameter of, for example, 1 μm or less. Therefore, it is possible to provide a lubricant excellent in lubricating properties such as extreme pressure properties, abrasion resistance, and friction resistance.

Particularly, the metal oxide particles are silica particles, the organic substance has at least one polysiloxane group per molecule, and at least one “Si—OR ¹ When the organic polymer (P) contains a group, a silica particle composite having better dispersibility in various media such as a liquid substance can be obtained. Therefore, there is an effect that a lubricant having more excellent lubrication characteristics can be provided.

Further, when the organic polymer is, for example, a block polymer or a graft polymer, a silica particle composite having better dispersibility in various media such as liquid substances can be obtained. Therefore, there is an effect that a lubricant having more excellent lubrication characteristics can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Taisei Tokuhisa 5-8, Nishiobari-cho, Suita-shi, Osaka Nippon Shokubai Co., Ltd. (72) Inventor Shigefumi Kuramoto 5-8, Nishimitabi-cho, Suita-shi, Osaka Company Nippon Shokubai

Claims (4)

[Claims] 1. A lubricant comprising a metal oxide particle composite surface-treated with an organic substance. 2. The metal oxide particle composite according to claim 1, wherein said metal oxide particle composite is obtained by treating metal oxide particles with an organic substance having a reactive group for said metal oxide particles. lubricant. 3. The method according to claim 1, wherein the metal oxide particle composite is used in a dispersion in which silica particles are dispersed.
And at least one “Si—OR ¹ group” (R ¹ is at least one group selected from the group consisting of a hydrogen atom, an alkyl group, and an acyl group). there are the alkyl and acyl groups a group which may be substituted; organic containing case where there are a plurality, the plurality of R ¹ may be the being the same or different) in which R ¹ is 1 molecule The lubricant according to claim 1 or 2, wherein the lubricant is obtained by treating the silica particles with a polymer (P). 4. The lubricant according to claim 1, further comprising a liquid material.