JP2007169325A - Electroconductive sliding material composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electroconductive sliding material composition having low friction, low abrasion, and electroconductivity of more than required for its antistatic properties jointly. <P>SOLUTION: This electroconductive sliding material composition is obtained by blending a lubrication-imparting material obtained by impregnating a lubricant in a porous material and particle-formed electroconductive material with a base material. The blending ratio of them is that the lubrication-imparting agent is ≥5 and <60 vol%, the particle-formed electroconductive material is ≥0.1 and <5 vol% and the base material is ≥40%, and the particle-formed electroconductive material has ≥500 m<SP>2</SP>/g surface area by the BET method and has a form of ≤50 nm primary particle diameter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a conductive sliding material composition such as a resin composition, an elastomer composition, and a coating film composition having both lubricity and conductivity.

The functions required for a sliding material composition such as a resin sliding material obtained by molding a lubricating resin composition, a sliding material having rubber elasticity, and a lubricating coating film are becoming increasingly severe year by year. In addition to the excellent low friction and low wear in the state and the addition of conductivity more than required for antistatic recently, there is a strong demand to combine these performances and maintain these initial characteristics for a long period of time. Yes. Conventionally, graphite, polytetrafluoroethylene (hereinafter referred to as PTFE) resin, molybdenum disulfide (hereinafter referred to as MoS ₂ ), boron nitride (hereinafter referred to as BN), etc. have been used to reduce friction and wear. The solid lubricant has been blended, or a reinforcing material such as glass fiber or carbon fiber has been blended into the resin to impart sliding properties. However, there is a limit to the reduction in frictional characteristics only by blending solid lubricants, and methods for blending lubricants such as lubricating oil have been attempted.

In the resin material in which the lubricating oil is blended, when the base resin layer is gradually worn during sliding and the lubricating oil layer appears on the sliding portion, the lubricating oil oozes out on the surface of the sliding portion. It is difficult to control the extent to which the lubricating oil oozes out, and the vacancies from which the lubricating oil has oozed out may cause a decrease in the strength of the resin layer. Furthermore, if an attempt is made to improve the mechanical strength and wear resistance by adding a filler, the effect of reinforcing may not be sufficient because the oil is localized at the interface of the filler.
As a method for solving these problems, a slide having excellent low friction and low wear properties is obtained by continuously supplying a lubricant to the surface of the sliding portion. A moving material composition is known (see Patent Document 1).

However, the oil-impregnated resin sliding material can reduce friction, which is superior to a sliding material blended with an oil-impregnating resin or solid lubricant that does not use a normal oil retaining body, but it simply blends a conductive material. It is difficult to impart conductivity only with this.
That is, the blended conductive material is concealed by a lubricating component such as oil, making it difficult for the conductive performance to be exhibited, or the lubricating component is held at the conductive material / resin interface, and the lubricating component necessary for sliding is the sliding interface. In some cases, the wear resistance and friction torque are remarkably deteriorated and the service life is shortened. Moreover, when using the axis | shaft which consists of soft materials, such as aluminum, as a sliding other material, the other material may be damaged by the above-mentioned oil shortage or the mix | blended electrically conductive material. In a resin composition such as Patent Document 1 in which porous silica and a lubricating component are blended, a resin composition having sufficient conductivity beyond that required for antistatic has not been known.
JP 2002-129183 A

  The present invention has been made in order to cope with such problems, and is required to have excellent low friction / low wear property and antistatic property capable of continuously supplying the lubricant to the surface of the sliding portion. An object of the present invention is to provide a conductive sliding material composition that can have a higher conductivity than the above and that does not damage a soft counterpart.

The conductive sliding material composition of the present invention is a conductive sliding material composition obtained by blending a base material with at least a lubricity imparting material composed of a porous body and a lubricant and a particulate conductive material. The blending ratio in the conductive sliding material composition is 5% by volume or more and less than 60% by volume for the lubricity imparting material, and 0.1% by volume or more and less than 5% by volume for the particulate conductive material. And the base material is 40 volume% or more, and the particulate conductive material has a surface area of 500 m ² / g or more by BET method and a primary particle diameter of 50 nm or less. . The primary particle diameter is a value measured by a microscope.
In the present invention, the base material refers to a substance capable of forming a sliding material, and particularly refers to a resin material, a material having rubber elasticity, and a material capable of forming a coating film.

The particulate conductive material is characterized by comprising carbon atoms.
The porous body has communication holes and has an average particle diameter of 0.5 μm to 100 μm.

The conductive sliding material composition of the present invention is required for antistatic property by the lubricity imparting performance in which the lubricant is held in the porous body and the lubricant can be supplied little by little at the sliding interface, and the particulate conductive material. It is possible to have the above conductive performance and prevent the soft mating member from being damaged. In particular, the conductive sliding material composition of the present invention is a particulate conductive material having a surface area of 500 m ² / g or more by the BET method and a primary particle diameter of 50 nm or less. The material is distributed and excellent conductivity can be imparted. Moreover, since the supply of the lubricant can be continued and the conductive material is dispersed throughout the conductive resin composition, these effects can be sustained over a long period of time.

  The lubricity-imparting material used in the present invention is a combination of a base material and a lubricant and a base material that could not be kneaded so far due to the compatibility between the base material and the lubricant by impregnating the porous body with the lubricant. However, it can be blended and kneaded without problems. Further, since a lubricant can be blended in the base material, a large amount of lubricant can be blended. In addition, when the base material is a resin that can be injection-molded, the screw slides during injection molding, the measurement becomes unstable, the cycle time becomes long, the dimensional accuracy is difficult to come out, and the lubricant adheres to the mold surface. As a result, problems such as poor finish of the molding surface do not occur.

As a result of intensive investigations to obtain a conductive sliding material composition having both long-lasting sliding characteristics and conductivity, a lubricity-imparting material comprising a porous body and a lubricant, and a particulate conductive material having predetermined characteristics The conductive sliding material composition obtained by blending at least a base material with a predetermined ratio can improve the friction and wear characteristics, and can also have more conductivity than required for antistatic, and It has been found that these characteristics can be maintained for a long time. The present invention is based on such knowledge.
By blending a particulate conductive material having predetermined characteristics into the conductive sliding material composition, the following effects were recognized.
(1) Since the conductive material has a shape with a surface area of 500 m ² / g or more by the BET method and a primary particle diameter of 50 nm or less, it can impart and maintain excellent conductivity to the entire conductive sliding material composition. . This is because the conductive material is very small and has a high specific surface area, and because of its shape, the interfacial energy of the base material / conductive material becomes very large, so it is dispersed in other materials constituting the conductive sliding material composition. In this case, it is easily rearranged, a percolation phenomenon occurs, and a uniform and fine conductive network can be formed in other materials even with a minimum blending amount.
(2) Since the conductive material is made of carbon atoms, it can provide more conductivity than required for antistatic.
(3) Since the conductive material has a surface area of 500 m ² / g or more and a primary particle diameter of 50 nm or less by the BET method consisting of carbon atoms, even when a soft material such as aluminum is used as the sliding partner material Can be used without damaging the mating material.
(4) By blending a predetermined amount of the conductive material, the wear resistance can be improved without impairing the sliding characteristics of the conductive sliding material composition, and conductivity can be imparted.

Moreover, the following effect | actions were recognized by mix | blending a lubricity imparting material with an electroconductive sliding material composition.
(1) Since the lubricant can be continuously supplied to the sliding interface, excellent friction and wear characteristics can be maintained.
(2) Since the oil content in the composition can be increased by blending the porous body impregnated with the lubricant, it can be blended more than the conventional lubricant blending amount of 5 vol% to 10 vol%.
(3) Since the lubricant component is held in the porous body, when the base material is a resin that can be injection-molded, the screw slips during injection molding, the measurement becomes unstable, and the cycle time becomes longer. There are no problems such as difficulty in accuracy and adhesion of lubricant to the mold surface, resulting in poor finish of the molding surface.
(4) Due to the compatibility of the base resin or elastomer material and the lubricant, even a combination of materials that could not be kneaded so far can be kneaded without problems.
(5) When considering the combined use of the oil-impregnated base material and the reinforcing material, if the lubricant and the reinforcing material are mixed and kneaded individually, the lubricant is easily localized at the interface between the reinforcing material and the base material. There is a case where the reinforcing effect cannot be sufficiently exhibited. However, if a lubricity imparting material in which a porous material is impregnated with a lubricant is kneaded with a reinforcing material, there is no lubricant at the interface between the reinforcing material and the base material, so that a predetermined reinforcing effect can be obtained.

The particulate conductive material used in the present invention may be any particulate conductive material having a surface area of 500 m ² / g or more by the BET method and a primary particle diameter of 50 nm or less.
Examples of conductive materials include metals and carbon-based materials, but among these, adhesion to metal materials generally used as sliding counterparts is small, and especially aggressiveness against soft materials such as aluminum is also small. Therefore, it is preferable to use a carbon-based material. More preferably, conductive carbon black is used as the carbon-based material.
By blending a predetermined amount of the conductive material, it is possible to improve the wear resistance without impairing the sliding characteristics of the conductive sliding material composition, and also acts as a filler for the base material. Strength can be improved.
Specific examples of the particulate conductive material that can be used in the present invention include Ketjen Black manufactured by Lion Co., Ltd. composed of conductive carbon black and fused and aggregated hollow shell particles.

  The mixing ratio of the particulate conductive material in the conductive sliding material composition of the present invention is 0.1 volume% or more and less than 5 volume%, preferably 0.5 volume% to 4 volume%. If it is less than 0.1% by volume, sufficient conductivity cannot be imparted and it cannot be used as an antistatic material or a conductive material. If it is 5% by volume or more, the wear resistance is particularly deteriorated, and the counterpart material may be damaged.

As the lubricity-imparting material used in the conductive sliding material composition of the present invention, it is preferable to use a porous body impregnated with a lubricant. By using the porous body impregnated with the lubricant, the lubricant can be continuously supplied to the sliding interface, so that excellent friction and wear characteristics can be maintained. Moreover, since the oil content in the composition can be increased by blending the porous body impregnated with the lubricant, it can be blended more than the conventional lubricant blending amount of 5% by volume to 10% by volume.
By holding the lubricant component in the porous body, when the base material is a resin that can be injection molded, the screw slips during injection molding, etc., the measurement becomes unstable, the cycle time becomes long, and the dimensional accuracy is increased. It does not cause problems such as being difficult to come out, and a lubricant adhering to the mold surface, resulting in a poor finished surface. Further, due to the compatibility between the base material and the lubricant, even combinations of materials that could not be kneaded so far can be kneaded without problems.
When considering the combined use of an oil-impregnated base material and a reinforcing material, the lubricant is localized at the interface between the reinforcing material and the base material if the lubricant and the reinforcing material are blended individually and kneaded. May not be fully demonstrated. However, if a lubricity-imparting material impregnated with a porous material, in particular a spherical porous material, is kneaded with the reinforcing material, there is no lubricant at the interface between the reinforcing material and the base material. Is obtained.

The method for impregnating the porous body with the lubricant can be used without particular limitation as long as the lubricant can be contained in the communicating holes of the porous body. For example, a method of obtaining a porous body impregnated with lubricating oil by putting a predetermined amount of a porous body and a lubricant in a stirrer and stirring for a predetermined time can be mentioned. In addition, when the porous body is fully impregnated with the lubricant, the predetermined amount of the porous body and excess lubricant are put into a stirrer and stirred until the liquid level of the lubricating oil does not decrease after the stirring is stopped. By doing so, an impregnated porous body can be obtained.
When the viscosity of the lubricant is high, the lubricant hardly penetrates into the spherical porous body. In that case, a method of impregnating the inside of the porous body with the lubricant by diluting with an appropriate solvent in which the lubricant dissolves, penetrating the diluted liquid into the porous body, gradually drying and volatilizing the solvent There is also.
Alternatively, the porous body is immersed in a lubricant and evacuated to force the lubricant to penetrate into the porous body. In the case of a solid lubricant at room temperature, the lubricant is heated to an appropriate temperature. Effective methods include the method of melting and impregnating, and the method of impregnating by reducing the viscosity of the lubricant by heating to an appropriate temperature when the viscosity is high even in a lubricant that is liquid at normal temperature. It is also possible to mix a liquid resin such as an unsaturated polyester resin with an oil-containing material of spherical porous silica, impregnate various woven fabrics, and laminate them to use as a lubricity imparting material.

  In the present invention, the blending amount of the lubricant in the lubricity-imparting material is 90 volume% to 150 volume% of the internal space volume of the porous body. If the inside of the porous body is not filled with an appropriate amount of lubricant, the lubricating effect cannot be obtained. In addition, if the amount of the lubricant is too large, the lubricant does not completely enter the porous body, and the lubricity-imparting materials aggregate together, so that the dispersion of the lubricity-imparting agent becomes uneven and stable sliding occurs. It becomes difficult to obtain characteristics. Further, excessive lubricant is dispersed in the molded body, and depending on the type of base material, the strength of the molded body may be reduced, or a problem may be caused during molding.

  The blending ratio of the lubricity-imparting material in the conductive sliding material composition of the present invention is 5 vol% or more and less than 60 vol%, more preferably 30 vol% to 50 vol%. If it is less than 5% by volume, sufficient lubricity cannot be imparted and the friction coefficient cannot be reduced. If it is 60% by volume or more, the amount of the base material becomes too small and the moldability becomes poor. In addition, the strength and wear resistance may be lowered, which is not preferable.

As the porous body that can be used in the present invention, any porous body that has communication holes and can be impregnated / held with a lubricant can be used. The average particle size is preferably about 0.5 μm to 100 μm, and particularly spherical. As such a porous body, a porous body made of an inorganic material such as true spherical porous silica, a porous body made of an organic material such as an acrylic resin, and a spherical polymer body such as a phenol resin formed into a spherical shape while being carbonized are porous. Known porous bodies and the like are known. The average particle diameter is a value measured by a microscopic method.
Here, the spherical shape means a sphere having a ratio of the short diameter to the long diameter of 0.8 to 1.0, and the true sphere means a sphere closer to the true sphere than the sphere.
Among these, it is preferable to use spherical porous silica that has communication holes, can be impregnated / held with a lubricant, has a property of being broken by the shearing force of the sliding interface, and does not damage the counterpart material. A preferred porous silica is a powder mainly composed of amorphous silicon dioxide. For example, precipitated silica, which is an aggregate of fine particles with a primary particle size of 15 nm or more, or an alkali silicate aqueous solution containing an alkali metal salt or alkaline earth metal salt is emulsified in an organic solvent and gelled with carbon dioxide. Examples thereof include true spherical porous silica (JP 2000-143228 A), which is an aggregate of primary fine particles having a particle diameter of 3 nm to 8 nm.

In the present invention, porous silica in which primary fine particles having a particle size of 3 nm to 8 nm are aggregated to form true spherical silica particles has communication holes and is destroyed by shear force at the sliding interface. Is particularly preferable. The true spherical silica particles have an average particle size of 0.5 μm to 100 μm. Such spherical silica particles can hold a lubricant therein, and can supply a small amount of the lubricant impregnated inside at the sliding interface. When the average particle size is less than 0.5 μm, the handling property is poor. Also, the amount of lubricant impregnation is not sufficient. When the average particle size exceeds 100 μm, the dispersibility in the molten resin is poor. In addition, the aggregate is broken by the shearing force applied during the kneading of the molten resin, and there is a possibility that the spherical shape cannot be maintained. Considering ease of handling and imparting sliding properties, the average particle size is particularly preferably 1 μm to 20 μm. As such a spherical porous silica, Asahi Glass Co., Ltd. product: Sunsphere, Suzuki Oil & Fats Co., Ltd. product: Gotball etc. can be illustrated.
Further, as a porous silica, there is Microid manufactured by Tokai Chemical Industry Co., Ltd.

Spherical silica particles having a particle diameter was set is 3 nm~8 nm primary particles has a specific surface area ^{200 m 2 / g~900 m 2 /} g, preferably ^{300 m 2 / g~800 m 2 /} g, fine Pore volume 1 ml / g to 3.5 ml / g, pore diameter 5 nm to 30 nm, preferably 20 nm to 30 nm, oil absorption 150 ml / 100 g to 400 ml / 100 g, preferably 300 ml / It preferably has a characteristic of 100 g to 400 ml / 100 g. Moreover, even if it is immersed in water and then dried again, it is preferable that the pore volume and the oil absorption remain at 90% by volume or more before immersion.
Here, the specific surface area and pore volume are values measured by a nitrogen adsorption method, and the oil absorption is a value measured according to JIS K5101. Moreover, it is preferable that the inside and the outer surface of the spherical silica particles are covered with a silanol group (Si—OH) because the lubricant can be easily held inside. Furthermore, the porous silica can be subjected to surface treatment such as organic or inorganic suitable for the base material.

The lubricant that can be used in the present invention is not particularly limited as long as it has a lubricating effect, such as a lubricating oil that is liquid at normal temperature, a wax that is solid at normal temperature, or a grease-like substance containing a thickener in the lubricating oil.
Lubricating oils include mineral oils such as spindle oil, refrigerator oil, turbine oil, machine oil, dynamo oil, hydrocarbon-based synthetic oils such as polybutene, poly-α-olefin, alkylnaphthalene, and alicyclic compounds, or natural oils and fats. And non-hydrocarbon synthetic oils such as ester oils, phosphate esters, diester oils, polyglycol oils, silicone oils, polyphenyl ether oils, alkyl diphenyl ether oils, alkylbenzenes, and fluorinated oils. If it is, you can use it. Among these, preferable results can be obtained by using silicone oil or the like for the conductive sliding material composition of the present invention requiring low friction. Silicone oil is particularly preferred because it has an affinity for the silanol groups remaining on the surface of the true spherical porous body. As the silicone oil, either a silicone oil having no functional group or a silicone oil having a functional group can be used.

Examples of the wax include paraffin waxes having 24 or more carbon atoms, olefin waxes having 26 or more carbon atoms, alkylbenzenes having 28 or more carbon atoms, hydrocarbon waxes such as crystalline microcrystalline wax, or myristic acid, Examples include higher fatty acid derivative waxes such as palmitic acid, stearic acid, arachidic acid, montanic acid, and unsaturated fatty acids having 18 or more carbon atoms (eg, octadecenoic acid, parinaric acid, etc.). As higher fatty acid derivative waxes, 1) higher fatty acid methyl and ethyl esters having 22 or more carbon atoms such as ethyl behenate and ethyl tricoate, higher fatty acids having approximately 16 or more carbon atoms and higher monovalent having 15 or more carbon atoms. Esters with alcohol, octadecyl stearate, higher fatty acid esters such as higher fatty acid triglycerides having 14 or more carbon atoms, 2) higher fatty acid amides such as palmitic acid amide, stearic acid amide, oleic acid amide, 3) stearic acid And salts of higher fatty acids such as lithium and calcium stearate with alkali metals and alkaline earth metals.

  In the grease-like substance, a thickener is added to the above-described lubricating oil that serves as a base oil. Examples of thickeners include 1) calcium soap, sodium soap, lithium soap, barium soap, aluminum soap, zinc soap, etc. 2) calcium soap as complex soap, Sodium-based complex soap, lithium-based complex soap, barium-based complex soap, aluminum-based complex soap, zinc-based complex soap, etc. There are urea / urethane compounds, diurethane compounds, silica airgel, montmorillonite, benton, PTFE resin, fluorinate ethylene propylene copolymer, BN, etc.

Examples of the substrate that can be used in the present invention include a resin material, a material having rubber elasticity, and a material capable of forming a coating film. Here, each material includes a material alone such as a resin alone, or a case where a reinforcing material or the like is blended in each material alone.
The resin material is not particularly limited as long as it is a synthetic resin capable of forming a form that can be used as a sliding material, such as a thermoplastic resin or a thermosetting resin. For example, polyethylene resin such as low density polyethylene, high density polyethylene, ultra high molecular weight polyethylene, modified polyethylene resin, water cross-linked polyolefin resin, polyamide resin, aromatic polyamide resin, polystyrene resin, polypropylene resin, silicone resin, urethane resin, PTFE resin , Chlorotrifluoroethylene resin, tetrafluoroethylene / hexafluoropropylene copolymer resin, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin, vinylidene fluoride resin, ethylene / tetrafluoroethylene copolymer resin, polyacetal resin, Polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene ether resin, polycarbonate resin, aliphatic polyketone resin, polyvinyl pyrrole Resin, polyoxazoline resin, polyphenylene sulfide resin, polyethersulfone resin, polyetherimide resin, polyamideimide resin, polyetheretherketone resin, thermoplastic polyimide resin, thermosetting polyimide resin, epoxy resin, phenol resin, Examples thereof include saturated polyester resins and vinyl ester resins. Moreover, the mixture of 2 or more types of materials chosen from the said synthetic resin, ie, a polymer alloy, etc. can be illustrated.

  Any material having rubber elasticity can be used as long as it is synthesized by various organic synthesis methods and has rubber elasticity at room temperature by vulcanization. Further, even an elastomer composed of a hard segment and a soft segment can be used. For example, acrylonitrile butadiene rubber, isoprene rubber, styrene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, butyl rubber, acrylic rubber, silicone rubber, fluorine rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, etc. Examples of such vulcanized rubbers include thermoplastic elastomers such as polyurethane elastomers, polyester elastomers, polyamide elastomers, polybutadiene elastomers, and soft nylon elastomers.

  As a material capable of forming a coating film, any resin component that can be dissolved or dispersed in an organic solvent can be used. Moreover, even the initial condensate which becomes high molecular weight by the curing reaction at the time of coating film formation can be used.

  The mixing ratio of the base material in the conductive sliding material composition of the present invention is 40% by volume or more. When the amount is less than 40% by volume, the amount of the base material is decreased, and the strength may be significantly lowered.

  Furthermore, in order to improve friction and wear characteristics and improve various mechanical properties, an appropriate filler can be added. For example, fiber such as glass fiber, aramid fiber, alumina fiber, boron fiber, silicon carbide fiber, silicon nitride fiber, BN fiber, quartz wool, metal fiber, or those knitted into a cloth shape, calcium carbonate, lithium phosphate Minerals such as lithium carbonate, calcium sulfate, lithium sulfate, talc, silica, clay, mica, inorganic whiskers such as titanium oxide whisker, potassium titanate whisker, aluminum borate whisker, calcium sulfate whisker, carbon black, graphite, Various thermosetting resins such as polyester fiber, polyimide resin and polybenzimidazole resin can be mentioned.

For the purpose of improving the slidability, an amino acid compound, polyoxybenzoyl polyester resin, polybenzimidazole resin, liquid crystal resin, aramid resin pulp, PTFE resin, BN, MoS ₂ , tungsten disulfide, or the like can be blended.

  Moreover, you may mix | blend a metal fiber, zinc oxide, etc. in order to improve thermal conductivity. It is of course possible to use a combination of a plurality of the above fillers. In addition, you may use together the additive which can be widely applied to general synthetic resin etc. with the compounding quantity which does not inhibit the effect of this invention. For example, industrial lubricants such as mold release agents, flame retardants, weather resistance improvers, and colorants may be added as appropriate, and the method of adding them is not particularly limited.

The conductive sliding material composition of the present invention is manufactured through a step of obtaining a lubricity imparting material and a step of blending the obtained lubricity imparting material and a particulate conductive material with a base material.
The step of obtaining the lubricity imparting material is a step of blending at least porous silica and a lubricant. A porous body such as porous silica and a lubricant are kneaded in advance, and the lubricant is impregnated in the communication holes of the porous body so that the lubricant is not released in the next step. While being held in the communication hole, it is blended into the base material together with the particulate conductive material and molded into a conductive sliding material, so that it can exhibit lubricity imparting performance that can supply a small amount of lubricant at the sliding interface. .
In addition, since porous bodies, such as porous silica, are easy to absorb moisture and absorb water, it is preferable to dry before impregnating lubricating oil. There is no particular limitation on the drying means, and drying in an electric furnace, vacuum drying, or the like can be employed. The method for impregnating the porous body with the lubricant is as described above.

  In the step of blending the obtained lubricity-imparting material and the particulate conductive material into the base material, a conventionally well-known method can be used as a general resin composition kneading method. For example, when the base material is a resin, the lubricity imparting material, the base material, and the conductive material are mixed with a mixer such as a Henschel mixer, ribbon blender, Ladige mixer, ball mill, tumbler mixer, etc., and then melt mixed. May be supplied to a good injection molding machine or a melt extruder (for example, a twin screw extruder), or may be melt-mixed in advance using a heat roller, kneader, Banbury mixer, melt extruder, or vacuum molding. Blow molding, foam molding, multilayer molding, heat compression molding, and the like may be performed.

  In the case of a coating composition, a porous body impregnated with a lubricant and a conductive material are blended with a resin component and mixed with a general coating liquid. The coating process can also be performed by a normal coating process. When performing the coating treatment, there is no particular limitation such as a spray method, an electrostatic coating method, or a fluidized immersion method.

  Furthermore, as long as the lubricity and conductivity of the conductive sliding material composition of the present invention are not impaired, in the form of intermediate products or final products, mechanical properties are separately obtained by chemical or physical treatment such as annealing treatment. And modification for improving properties such as conductivity.

  The usage example of the conductive sliding material composition of the present invention is not particularly limited as long as it is a sliding portion. For example, sliding parts such as sliding bearings, gears, sliding sheets, seal rings, rollers, various carriages, rolling bearing cages, solid lubricants, rolling bearing seals, linear bearing seals, ball screw balls and balls There are sliding materials such as spacers and rolling bearing races.

Examples 1 to 5 and Comparative Examples 1 to 10
Spherical porous silica as a porous material, manufactured by Asahi Glass Co., Ltd .: Sunsphere H53 (average particle size 5 μm), silicone oil as a lubricant, Shin-Etsu Silicone Co., Ltd .: KF96H, polyethylene resin as a base material, manufactured by Mitsui Chemicals Lübmer L5000 was prepared for each. Lubricating material was produced by impregnating spherical porous silica with 1 volume of spherical porous silica and impregnating spherical porous silica with 6 times the volume of silicone oil. The obtained lubricity-imparting material and the conductive material shown in Table 1 were added to the polyethylene resin in the proportions shown in Table 2, and melt-kneaded using a biaxial extruder to obtain pellets.

The pellets were injection-molded to form a sliding material test piece having a diameter of 5 mm and a length of 15 mm. The obtained sliding material test piece was cut to produce a pin test piece having a diameter of 3 mm and a length of 10 mm. A surface with a diameter of 3 mm was brought into contact with a rotating disk counterpart, and a friction / wear test and a formability test were performed under the following conditions and evaluation methods. The results are shown in Table 2.
<Friction and wear test>
Testing machine: Pin-on-disk friction and wear testing machine Counterpart: Aluminum alloy A5056 (Ra = 0.8μm)
Surface pressure: 3 MPa
Peripheral speed: 4.2 m / min.
Temperature: 30 ℃
Time: 20h
Atmosphere: In the air Measurement items and evaluation criteria are shown below.
Specific wear amount: Calculate the specific wear amount from the difference between the length of the pin test piece before the test and the length of the pin test piece after the test, and evaluate that it is less than 500 × 10 ^-8 mm / (N · m). “X” is also shown in Table 2, respectively.
Coefficient of friction: The average value for 1 hour before the end of the test was measured. Table 2 also shows “○” when 0.1 or less is evaluated as acceptable, and “×” when other is evaluated as impossible.
Damage condition on the surface of the mating material: The condition of the mating material before and after the test was visually observed and evaluated as good if there was no damage. It was written together.
<Formability test>
Formability: When injection molding to produce a sliding material test piece, it is evaluated as “Yes” if it can be molded without any problem, “No” if it cannot be molded or if it is inferior in fluidity, “X” Are also shown in Table 2.

<Conductivity test>
Further, compression molding was performed using the above pellets to form a conductive test piece having a diameter of 30 mm and a thickness of 1 mm. The obtained conductive test piece is made of stainless steel SUS303 with a diameter of Φ20 mm × height of 10 mm, and is sandwiched between two mirror-finished electrodes with a surface roughness Ra of 0.04 μm or less and a surface pressure of 3 mm. After pressurizing with MPa, the resistance value after 5 minutes was measured with a digital multimeter. The volume resistance value is obtained from the measured resistance value, and 10 ⁹ Ω · cm or less is evaluated as being excellent in conductivity, ◯ is evaluated, and the others are evaluated as being inferior in conductivity, and X is displayed. It was written together in 2.
<Comprehensive evaluation>
All evaluations in the friction and wear test, the formability test, and the conductivity test are “◯”, the overall evaluation is “○”, and at least one is “×”, the overall evaluation is “×”. .

As shown in Table 2, all of the examples exhibited excellent sliding characteristics and conductivity.
Comparative Example 1 was excellent in friction and wear characteristics, but was an insulator because it did not contain a conductive material.
Comparative Example 2 was excellent in conductivity because it contained a predetermined amount of conductive material, but had a high friction coefficient of 0.1 or more and poor friction and wear characteristics because a predetermined amount of lubricity imparting material was not blended.
In Comparative Example 3, since the lubricity-imparting material was blended over a predetermined amount range and the resin content was small, pellets were obtained but injection molding could not be performed.
In Comparative Example 4, since the conductive material exceeded a predetermined amount, the friction and wear characteristics were remarkably deteriorated. In addition, damage to the mating material, which was a soft material, occurred. Although injection molding was possible, the fluidity was very poor and the moldability was poor.
In Comparative Example 5, the conductive material was a conductive material that did not have the characteristics disclosed in the present invention, so the composition did not have a conductivity of 10 ⁹ Ω · cm or less. In addition, the wear resistance was remarkably deteriorated.
Comparative Example 6 was mixed with Comparative Example 5 by increasing the conductive material. The conductivity was 10 ⁹ Ω · cm or less, but the frictional properties and wear resistance were significantly deteriorated.
In Comparative Example 7, the conductive material used had a primary particle size of 24 nm, but the surface area did not have the characteristics disclosed in the present invention, and therefore had a conductivity of 10 ⁹ Ω · cm or less. There wasn't. In addition, the wear resistance deteriorated.
Comparative Example 8 was mixed with Comparative Example 7 by increasing the conductive material. The conductivity was 10 ⁹ Ω · cm or less, but the frictional properties and wear resistance were significantly deteriorated.
In Comparative Example 9, since a conductive material having a remarkably large particle diameter and a remarkably small surface area with respect to the characteristics disclosed in the present invention was used, the conductive material did not have a conductivity of 10 ⁹ Ω · cm or less.
Comparative Example 10 was mixed with Comparative Example 9 with a significantly increased conductive material. However, it did not exhibit conductivity of 10 ⁹ Ω · cm or less, the friction characteristics were remarkably deteriorated, and the wear resistance was also deteriorated.

  Since the conductive sliding material composition of the present invention has both excellent sliding characteristics and conductivity, sliding parts such as sliding bearings, gears, sliding sheets, seal rings, rollers, various carriages, and bearings such as rolling bearings. Conductive sliding material composition even when required to prevent electrification due to friction or energization, such as holders, seals, lace materials, spacers such as ball screws that require slidability, solid lubricants, etc. It can be suitably used as a product. Further, even when a soft material such as aluminum is used as a sliding partner material, it can be suitably used without particularly damaging the partner material.

Claims (3)

A conductive sliding material composition formed by blending at least a lubricity-imparting material composed of a porous body and a lubricant and a particulate conductive material on a base material,
The blending ratio in the conductive sliding material composition is 5% by volume or more and less than 60% by volume for the lubricity imparting material, and 0.1% by volume or more and less than 5% by volume for the particulate conductive material. And the substrate is at least 40% by volume,
The conductive conductive material composition, wherein the particulate conductive material has a shape with a surface area of 500 m ² / g or more by BET method and a primary particle diameter of 50 nm or less.   The conductive sliding material composition according to claim 1, wherein the particulate conductive material comprises carbon atoms. The conductive sliding material composition according to claim 1, wherein the porous body has communication holes and has an average particle diameter of 0.5 μm to 100 μm.