WO2017033986A1 - Composition de caoutchouc, objet moulé en caoutchouc et procédé pour sa production - Google Patents

Composition de caoutchouc, objet moulé en caoutchouc et procédé pour sa production Download PDF

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Publication number
WO2017033986A1
WO2017033986A1 PCT/JP2016/074717 JP2016074717W WO2017033986A1 WO 2017033986 A1 WO2017033986 A1 WO 2017033986A1 JP 2016074717 W JP2016074717 W JP 2016074717W WO 2017033986 A1 WO2017033986 A1 WO 2017033986A1
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rubber
molded product
rubber molded
parts
carbon black
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PCT/JP2016/074717
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English (en)
Japanese (ja)
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忠志 笠本
和志 坂手
卓志 平山
隆司 小村
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内山工業株式会社
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Priority to JP2017536470A priority Critical patent/JP6745534B2/ja
Publication of WO2017033986A1 publication Critical patent/WO2017033986A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K9/00—Use of pretreated ingredients
    • C08K9/04—Ingredients treated with organic substances
    • C08K9/06—Ingredients treated with organic substances with silicon-containing compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/06—Sulfur
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
    • C08L9/02—Copolymers with acrylonitrile
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3204—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip
    • F16J15/3232—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings with at least one lip having two or more lips
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
    • F16J15/3284—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings characterised by their structure; Selection of materials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/002—Physical properties
    • C08K2201/006—Additives being defined by their surface area
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/014—Additives containing two or more different additives of the same subgroup in C08K
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/34—Silicon-containing compounds

Definitions

  • the present invention relates to a rubber composition and a rubber molded product.
  • the present invention also relates to a method for producing the rubber molded product.
  • An automobile axle is supported by a rolling bearing, and this bearing is equipped with a part called a seal to prevent leakage of grease and intrusion of muddy water.
  • the seal is a ring-shaped metal core whose surface is covered with rubber.
  • a conductive rubber composition is used for the seal as a measure against radio noise. Examples of the conductive rubber composition used for sealing include nitrile rubber compositions described in Patent Documents 1 to 3.
  • Patent Document 1 contains 5 to 50 parts by weight of carbon black, 5 to 60 parts by weight of graphite having an average particle diameter of 5 ⁇ m or less, and 5 to 50 parts by weight of conductive carbon other than these with respect to 100 parts by weight of nitrile rubber.
  • a nitrile rubber composition in which the total amount of carbon black, graphite and other conductive carbon is 10 to 100 parts by weight with respect to 100 parts by weight of nitrile rubber is described.
  • the oil seal using the rubber composition of patent document 1 is supposed to satisfy muddy water resistance, sealing performance, and low torque property.
  • Patent Document 2 discloses that 5 to 50 parts by weight of carbon black, 5 to 60 parts by weight of graphite having an average particle diameter of 5 ⁇ m or less, 5 to 50 parts by weight of other conductive carbon, based on 100 parts by weight of nitrile rubber, 1 to 5 parts by weight of alkylated diphenylamine consisting of the reaction product of diphenylamine with styrene and 2,4,4-trimethylpentene as an anti-aging agent, and N, N′-di-2-naphthyl-p-phenylenediamine or A nitrile rubber composition comprising 0.5 to 2.5 parts by weight of dilauryl thiodipropionate is described.
  • Patent Document 3 discloses that 5 to 50 parts by weight of carbon black, 5 to 60 parts by weight of graphite having an average particle diameter of 5 ⁇ m or less, 5 to 50 parts by weight of other conductive carbon, and 100 parts by weight of nitrile rubber; A nitrile rubber composition containing 0.5 to 3.5 parts by weight of 2,5-ditertiarybutylhydroquinone or 2,5-ditertiary amylhydroquinone as an antioxidant is described.
  • the bearing Since the bearing is mounted outside the vehicle, it is exposed to muddy water and rainwater.
  • sodium chloride and calcium chloride are sprayed on the road as antifreezing agents and snow melting agents. Therefore, muddy water and rainwater containing sodium chloride and calcium chloride may adhere to the seal, which causes electrolysis to generate alkali, causing the problem that the conductive rubber swells and deforms, and the core metal corrodes. .
  • Patent Document 1 no consideration has been given to preventing the deformation of the conductive rubber and the corrosion of the core metal. Moreover, in patent documents 2 and 3, although the volume change rate of the rubber
  • JP 2012-97213 A International Publication No. 2015/5080 International Publication No. 2015/5081
  • the above-mentioned problems include 100 parts by mass of nitrile rubber (A), 1 to 30 parts by mass of conductive carbon black (B) having a DBP oil absorption of 150 mL / 100 g or more and 1000 mL / 100 g or less, and 5 to 60 silylated clay (C). This is solved by providing a rubber composition containing parts by weight.
  • the rubber composition further contains 2 to 50 parts by mass of carbon black (D) having a DBP oil absorption of 30 mL / 100 g or more and less than 150 mL / 100 g.
  • D carbon black
  • silylated clay (C) is silylated with alkoxysilane. It is also preferred that the alkoxysilane is a silane coupling agent.
  • the above problem can also be solved by providing a rubber molded product obtained by vulcanizing the rubber composition.
  • the volume resistance value is preferably 1 ⁇ 10 5 ⁇ ⁇ cm or less. It is also preferable that the water contact angle on the surface of the rubber molded product 40 minutes after the dropping of the water droplet is 40 ° or more.
  • the above object is a method for producing the rubber molded article, in which the nitrile rubber (A), the conductive carbon black (B), the silylated clay (C) and the vulcanizing agent (E) are kneaded and the rubber composition
  • This can also be solved by providing a method for producing a rubber molded article comprising a kneading step for obtaining a product and a vulcanization step for vulcanizing the rubber composition.
  • the said subject is a manufacturing method of the said rubber molded product, Comprising: Nitrile rubber (A), electroconductive carbon black (B), unsilylated clay (F), alkoxysilane (G), and vulcanizing agent
  • Nitrile rubber A
  • electroconductive carbon black B
  • unsilylated clay F
  • alkoxysilane G
  • vulcanizing agent The problem can also be solved by providing a method for producing a rubber molded article comprising a kneading step of kneading (E) to obtain a rubber composition and a vulcanization step of vulcanizing the rubber composition.
  • a sealing member composed of the rubber molded product and the cored bar is a preferred embodiment of the present invention.
  • the sealing device is mounted between the two members, the inner member of which is rotatably supported with respect to the outer member, the first member including a slinger that is integrally attached to the inner member, and the outer member A metal core integrally attached to the member and a second member provided with the rubber molded product fixed to the metal core, and the rubber molded product has a lip portion that elastically contacts or approaches the slinger,
  • the first member and the second member form a labyrinth structure portion (R1) facing in parallel with the rotation axis direction, and the rubber molded product faces the first member and the labyrinth structure portion (
  • a sealing device characterized by forming R1) is also a preferred embodiment of the present invention.
  • the first member and the second member further form a labyrinth structure portion (R2) that is perpendicular to the rotation axis direction, and the rubber molded product is opposed to the first member.
  • the labyrinth structure (R2) is preferably formed.
  • the first member has a magnetic rubber molded product fixed to the slinger, and the magnetic rubber molded product forms the labyrinth structure portion (R1) facing the rubber molded product. .
  • the present invention it is possible to provide a rubber molded article excellent in conductivity and weather resistance and a method for producing the same. Moreover, the rubber composition for obtaining such a rubber molded product can be provided.
  • FIG. 1 It is a figure (sectional view) which shows a part of example of the bearing using the sealing member of this invention. It is a figure (sectional view) which shows a part of seal member of Example 1.
  • FIG. It is a figure which shows the sealing device of Example 5.
  • FIG. It is a figure which shows the sealing device of Example 6.
  • the rubber composition of the present invention contains nitrile rubber (A), conductive carbon black (B) having a DBP oil absorption of 150 mL / 100 g or more and 1000 mL / 100 g or less, and silylated clay (C).
  • the rubber molded product of the present invention is obtained by vulcanizing the rubber composition.
  • silylated clay (C) it is important to use silylated clay (C).
  • the inventors of the present invention obtained a specific amount of silylated clay (C) in a rubber composition containing nitrile rubber (A) and conductive carbon black (B). It was found that a rubber molded article having excellent conductivity and weather resistance can be obtained by vulcanizing the rubber composition.
  • the rubber composition of the present invention will be described.
  • Nirile rubber (A) The nitrile rubber (A) used in the present invention is not particularly limited, and a copolymer of acrylonitrile and 1,3-butadiene can be used. Hydrogenation to the double bond remaining in the 1,3-butadiene unit after polymerization is optional.
  • Non-hydrogenated nitrile rubber hereinafter sometimes abbreviated as NBR
  • HNBR hydrogenated nitrile rubber
  • the content of acrylonitrile units in the nitrile rubber (A) is preferably 15 to 50% by mass.
  • the content of 1,3-butadiene units occupies the whole or most of the remainder including those hydrogenated.
  • the nitrile rubber (A) used in the present invention may contain structural units derived from other copolymerizable monomers as long as the effects of the present invention are not impaired. For example, it may contain a functional group such as a carboxyl group or a carboxylic anhydride group.
  • the conductive carbon black (B) used in the present invention is blended to impart conductivity to a rubber molded product, and by using this, a rubber molded product having a low volume resistance value is obtained. Can do. By using a rubber molded product containing conductive carbon black (B) for the seal of the bearing, radio noise can be effectively suppressed.
  • the DBP oil absorption of the conductive carbon black (B) is 150 mL / 100 g or more.
  • the DBP oil absorption indicates the amount (mL) of dibutyl phthalate (DBP) that can be absorbed by 100 g of carbon black (in accordance with JIS K6217-4). This value increases as the aggregate and agglomerate structures develop. And carbon black excellent in electroconductivity has a large DBP oil absorption.
  • DBP dibutyl phthalate
  • a rubber molded product having a low volume resistance value can be obtained by using conductive carbon black (B) having a DBP oil absorption of 150 mL / 100 g or more.
  • the DBP oil absorption of carbon black (B) is preferably 200 mL / 100 g or more, and more preferably 300 mL / 100 g or more.
  • the DBP oil absorption of carbon black (B) is usually 1000 mL / 100 g or less. When the DBP oil absorption exceeds 1000 mL / 100 g, the fluidity of the rubber composition may be deteriorated.
  • the DBP oil absorption is preferably 800 mL / 100 g or less, and more preferably 600 mL / 100 g or less.
  • the average primary particle size of the carbon black (B) is preferably small, and preferably 10 to 50 nm.
  • the blending amount of carbon black (B) is 1 to 30 parts by mass with respect to 100 parts by mass of nitrile rubber (A). When the blending amount of carbon black (B) is less than 1 part by mass, the resulting molded article has insufficient conductivity.
  • the compounding amount of carbon black (B) is preferably 2 parts by mass or more, and more preferably 4 parts by mass or more. On the other hand, when the compounding amount of carbon black (B) exceeds 30 parts by mass, the moldability deteriorates.
  • the blending amount of carbon black (B) is preferably 20 parts by mass or less.
  • the type of carbon black (B) used in the present invention is not particularly limited as long as the DBP oil absorption amount is in the above range, and the volume resistance value of the obtained molded product is a certain value or less.
  • Specific examples include Ketjen Black, Acetylene Black, “Vulcan® XC-72” manufactured by Cabot, “Conductex® 7055® Ultra” manufactured by Colombian International, and “Printex® XE2® B” manufactured by Evonik Degussa.
  • ketjen black is preferable because it can provide conductivity without deteriorating fluidity.
  • Ketjen Black is a conductive carbon black marketed by Lion Corporation. The structure of aggregates and agglomerates is highly developed, and the primary particles have a hollow structure. Can be granted.
  • the clay (C) used in the present invention is a clay having a silylated surface.
  • Clay is a powder composed of fine mineral particles mainly composed of hydrous aluminum silicate.
  • the type of the clay is not particularly limited as long as the surface can be silylated, and examples thereof include kaolin, wax, sericite, talc, and montmorillonite.
  • the clay used in the present invention may be a wet clay, a dry clay, or a fired clay obtained by firing these. Further, clays are generally classified into hard clays and soft clays depending on the hardness of the kneaded dough when blended with rubber, and any of them may be used. These clays can be appropriately used depending on the required performance of the rubber molded product to be obtained.
  • the surface of the clay (C) is silylated with alkoxysilane.
  • the clay (C) having a silylated surface by reacting the hydroxyl group on the clay surface with the alkoxy group of the alkoxysilane can be obtained.
  • the alkoxysilane is a silane coupling agent from the viewpoint of miscibility with the nitrile rubber (A).
  • a silane coupling agent is an alkoxysilane to which an organic group having a reactive functional group is bonded.
  • the reactive functional group include vinyl group, epoxy group, styryl group, methacryl group, acrylic group, amino group, isocyanurate group, ureido group, mercapto group, sulfide group, and isocyanate group.
  • a clay silylated with a coupling agent having a mercapto group it is preferable to use a clay silylated with a coupling agent having a mercapto group, and from the viewpoint of water resistance, a clay silylated with a coupling agent having an amino group should be used. Is preferred.
  • the blending amount of clay (C) is 5 to 60 parts by mass with respect to 100 parts by mass of nitrile rubber (A). When the amount of clay (C) is less than 5 parts by mass, the effect of adding clay (C) becomes insufficient.
  • the blending amount of clay (C) is preferably 10 parts by mass or more. On the other hand, if the blending amount of clay (C) exceeds 60 parts by mass, moldability deteriorates.
  • the blending amount of clay (C) is preferably 50 parts by mass or less.
  • the average particle size of the clay (C) is preferably 0.2 to 8.0 ⁇ m.
  • the rubber composition further contains 5 to 50 parts by mass of carbon black (D) having a DBP oil absorption of 30 mL / 100 g or more and less than 150 mL / 100 g. It is preferable.
  • carbon black (D) will be described.
  • the carbon black (D) used in the present invention preferably has a DBP oil absorption of 30 mL / 100 g or more and less than 150 mL / 100 g.
  • This carbon black (D) is one in which the structure of aggregates and agglomerates is not developed as much as the conductive carbon black (B), and most of the carbon black compounded in general rubber compositions is included in this carbon black (D). .
  • the DBP oil absorption of carbon black (D) is more preferably 130 mL / 100 g or less.
  • the DBP oil absorption of carbon black (D) is more preferably 50 mL / 100 g or more.
  • the type of carbon black (D) used in the present invention is not particularly limited as long as the DBP oil absorption is in the above range. Specifically, FEF, SRF, SAF, ISAF, HAF, MAF, GPF, FT, MT and the like can be used, and FEF and SRF are preferable from the viewpoint of balance between performance and cost. Two or more types of carbon black (D) may be used in combination.
  • the compounding amount of carbon black (D) is preferably 2 to 50 parts by mass with respect to 100 parts by mass of nitrile rubber (A). When the blending amount of carbon black (D) is less than 2 parts by mass, the hardness may be insufficient.
  • the amount of carbon black (D) is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. On the other hand, if the blending amount of carbon black (D) exceeds 50 parts by mass, moldability may be deteriorated.
  • the compounding amount of carbon black (D) is preferably 40 parts by mass or less.
  • the average primary particle diameter of carbon black (D) is usually 10 to 200 nm.
  • the rubber composition may contain other components than the nitrile rubber (A), the conductive carbon black (B), and the clay (C) having a silylated surface as long as the effects of the present invention are not inhibited. It doesn't matter.
  • a vulcanizing agent in addition to the above-described carbon black (D), a vulcanizing agent, a vulcanization aid, a vulcanization accelerator, a vulcanization retarder, an adhesive, an acid acceptor, a colorant, a filler, a plasticizer
  • various additives such as processing aids and anti-aging agents.
  • the method for producing the rubber molded product of the present invention is not particularly limited, but preferred methods include the following method (1) and method (2). First, the method (1) will be described.
  • Method (1) includes a kneading step of kneading nitrile rubber (A), conductive carbon black (B), silylated clay (C) and vulcanizing agent (E) to obtain a rubber composition, and the rubber And a vulcanization step of vulcanizing the composition.
  • nitrile rubber (A), conductive carbon black (B), and clay (C) having a silylated surface the above-described ones can be used, and the blending amount thereof can also be the above-mentioned amount.
  • a material other than nitrile rubber (A), conductive carbon black (B), and clay (C) having a silylated surface is added. be able to.
  • Carbon black (D) can use what was mentioned above, and can also make it the amount mentioned above.
  • the method of mixing the above components in the kneading step is not particularly limited, and kneading can be performed using an open roll, a kneader, a Banbury mixer, an intermixer, an extruder, or the like. Especially, it is preferable to knead
  • the temperature during kneading is preferably 20 to 120 ° C.
  • the rubber composition obtained in the present invention is obtained by molding the rubber composition thus obtained and vulcanizing it in the next vulcanization step.
  • Examples of the molding method of the rubber composition include injection molding, extrusion molding, compression molding, roll molding and the like. Of these, injection molding and compression molding are preferred. At this time, it may be vulcanized after being previously molded, or may be vulcanized simultaneously with the molding. Further, it may be vulcanized at the same time as molding and then further secondary vulcanized.
  • the vulcanization temperature is usually preferably 150 to 200 ° C.
  • the vulcanization time is usually 5 to 60 minutes.
  • a heating method for vulcanization general methods used for rubber vulcanization such as compression heating, steam heating, oven heating, hot air heating and the like are used.
  • the method of vulcanization is not particularly limited, and examples thereof include sulfur vulcanization, peroxide vulcanization, and amine vulcanization.
  • a vulcanizing agent for sulfur vulcanization sulfur or a sulfur-containing compound is used.
  • An organic peroxide is used as a vulcanizing agent for vulcanizing the peroxide.
  • the amount of the vulcanizing agent (E) used at this time is usually 0.1 to 10 parts by mass with respect to 100 parts by mass of the nitrile rubber (A).
  • Method (2) is a method in which a nitrile rubber (A), conductive carbon black (B), non-silylated clay (F), alkoxysilane (G), and a vulcanizing agent (E) are kneaded to obtain a rubber composition. A kneading step to be obtained and a vulcanizing step for vulcanizing the rubber composition.
  • the difference from the method (1) is that the clay (C) having a silylated surface is not added and kneaded, but the non-silylated clay (F) and the alkoxysilane (G) are mixed.
  • the surface of the clay (F) is silylated in the kneading step.
  • the hydroxyl group on the surface of the clay (F) reacts with the alkoxy group of the alkoxysilane (G) to obtain a clay having a silylated surface.
  • alkoxysilane (G) is a silane coupling agent.
  • the silane coupling agent those described above can be used.
  • the clay (F) used at this time is not specifically limited, The various clay demonstrated as a raw material of the silylated clay (C) can be used.
  • the amount of alkoxysilane (G) is not particularly limited as long as it can silylate the surface of clay (F). However, if the amount of alkoxysilane (G) is too large, the fluidity of the rubber composition is lowered, and the rubber properties such as tensile strength and elongation may be deteriorated. From this viewpoint, the amount of alkoxysilane (G) is preferably 50 parts by mass or less and more preferably 30 parts by mass or less with respect to 100 parts by mass of clay (F). On the other hand, if the amount of alkoxysilane (F) is too small, the surface of clay (F) may not be silylated.
  • the amount of the alkoxysilane (G) is preferably 0.5 parts by mass or more and more preferably 2 parts by mass or more with respect to 100 parts by mass of the clay (F).
  • the amount of clay (F) can be the same as the amount of clay (C) described above.
  • Carbon black (D) can use what was mentioned above, and can also make it the amount mentioned above.
  • the rubber composition obtained in the present invention is obtained by molding the rubber composition thus obtained and vulcanizing it in the next vulcanization step.
  • the vulcanization step is the same as the step described in method (1).
  • the method (1) is preferable when the performance of the obtained rubber molded product is emphasized, and the method (2) is preferable when the production cost is important. .
  • the volume resistance value of the rubber molded product thus obtained is preferably 1 ⁇ 10 5 ⁇ ⁇ cm or less. If the volume resistance value exceeds 1 ⁇ 10 5 ⁇ ⁇ cm, radio noise may not be effectively suppressed when a rubber molded product is used for the seal.
  • the volume resistance value is more preferably 1 ⁇ 10 4 ⁇ ⁇ cm or less.
  • the volume resistance value is usually 10 ⁇ ⁇ cm or more.
  • the volume resistance value is a value obtained by measurement by the Wheatstone bridge method according to JIS C2139.
  • the water contact angle on the surface of the rubber molded product 40 minutes after the dropping of the water droplet is 40 ° or more. Since the water contact angle is large, it becomes difficult to wet the alkaline aqueous solution generated by electrolysis, so that the rubber molded product can be prevented from swelling and deforming, and the weather resistance is improved.
  • the water contact angle is more preferably 50 ° or more.
  • a preferred embodiment of the present invention is a part in which the rubber molded product of the present invention and a metal member are bonded, and a more preferred embodiment is a seal member comprising the rubber molded product of the present invention and a cored bar. is there. Since the rubber molded article of the present invention has conductivity, there is a possibility that a battery is formed between the rubber molded article and the metal core, and the aqueous solution in contact therewith is electrolyzed to produce an alkaline aqueous solution.
  • the rubber molded article of the present invention is particularly effective in a mode of contacting with a metal because the rubber molded article can be prevented from swelling or deforming by such an alkaline aqueous solution.
  • FIG. 1 is a view (sectional view) showing a part of an example of a bearing 1 using a seal member 2A of the present invention.
  • the bearing 1 shown in FIG. 1 includes a seal member 2A.
  • the sealing member 2A includes a cored bar 3A and a rubber molded product 4A bonded to the cored bar 3A.
  • the rubber molded product 4A has lip portions 5a to 5c.
  • muddy water or the like tends to accumulate between the rubber molded product 4 ⁇ / b> A and the outer ring 6 (location indicated by 7).
  • muddy water or the like may accumulate between the rubber molded product 4A and the hub wheel 8 (location indicated by 9).
  • a particularly suitable application of the present invention is a seal for a rolling bearing. Since the bearing is mounted outside the vehicle, it is exposed to muddy water and rainwater. In addition, sodium chloride as an antifreeze agent and calcium chloride as a snow melting agent are sprayed on the road. Therefore, muddy water or rainwater containing sodium chloride or calcium chloride may adhere to the seal, which causes a problem that the conductive rubber swells and deforms, and the core metal corrodes. Therefore, the rubber molded product of the present invention, which can suppress this problem and has excellent weather resistance, is particularly preferably used.
  • the method for producing the seal member is not particularly limited, and examples thereof include a method in which a metal mold and a rubber composition in the present invention are filled and pressed. Thereby, the sealing member by which the rubber molded product was coat
  • the metal core used at this time may be a metal plate made of iron, aluminum, or the like, or an alloy plate thereof. These core bars may be subjected to surface treatment such as plating. For example, SECC indicated by JIS G3313, SUS301 indicated by JIS G4305, SPCC indicated by JIS G3141 and the like can be mentioned. From the viewpoint of improving the adhesion between the rubber molded product and the cored bar, the cored bar may have an adhesive applied to the surface thereof. Examples of the adhesive include a phenol-based adhesive, an epoxy-based adhesive, and a silane coupling agent.
  • the shape of the metal core is not particularly limited, but is usually a ring shape. Further, the thickness of the core metal and the thickness of the rubber molded product are not particularly limited, and can be appropriately set according to the size of the rolling bearing.
  • the sealing device (11) shown in FIG. 3 is an example of a sealing device (11) used for a bearing of a wheel support portion of an automobile or the like.
  • the sealing device (11) is mounted between the two members on which the inner member (82) is rotatably supported with respect to the outer member (81).
  • the sealing device (11) includes a first member (1a) having a slinger (11a) attached integrally to the inner member (82).
  • the slinger (11a) is for preventing intrusion of muddy water from the outside and protecting the bearing.
  • the material of the slinger (11a) the same material as the core bar used in the sealing member described above can be used.
  • the shape of the slinger (11a) is not particularly limited, but is usually a ring shape.
  • the dimension of a slinger (11a) is not specifically limited, It can set suitably according to the magnitude
  • the magnetic rubber molded article (12a) is fixed to the slinger (11a).
  • the magnetic rubber molded product (12a) can be obtained by vulcanizing a magnetic rubber composition containing magnetic powder.
  • various rubbers are used, but nitrile rubber is preferably used from the balance of oil resistance, heat resistance, price, and the like.
  • the magnetic powder include ferrite magnetic powder and rare earth magnetic powder. Ferrite magnetic powder is preferably used from the viewpoint of cost and durability.
  • the method for fixing the magnetic rubber molded article (12a) to the slinger (11a) is not particularly limited.
  • the magnetic rubber composition is placed on the slinger (11a) pre-applied with an adhesive and pressed, or bonded to the mold. And a method of filling and pressing the slinger (11a) previously coated with the agent and the magnetic rubber composition.
  • the sealing device (11) includes a second member (2a) including a metal core (21a) integrally attached to the outer member and a rubber molded product (22a) fixed to the metal core (21a). Further, the rubber molded product (22a) has lip portions (23a to 25a) that elastically contact the slinger (11a). At this time, the lip portions (23a to 25a) may be close to the slinger (11a).
  • the second member (2a) corresponds to an example of the sealing member described above.
  • the rubber molded product (22a) in the second member (2a) is the above-described rubber molded product of the present invention, and conductive carbon having 100 parts by mass of nitrile rubber and a DBP oil absorption of 150 mL / 100 g or more and 1000 mL / 100 g or less.
  • the first member (1a) and the second member (2a) form a labyrinth structure portion (R1) that faces the rotation axis (L) in parallel.
  • the labyrinth structure part (R1) forms a gap between the first member (1a) and the second member (2a), and foreign matter enters the space (S) in the sealing device (11).
  • the rubber molded product (22a) having a large water contact angle faces the first member (1a) to form the labyrinth structure portion (R1).
  • the width (d1) of the gap is usually 0.1 to 1.0 mm.
  • the labyrinth structure portion (R1) extends in the direction of the rotation axis (L), but the length in the direction of the rotation axis (L) is not particularly limited, but is usually 0.5 mm or more. Therefore, the length of the labyrinth structure portion (R1) in the direction of the rotation axis (L) is appropriately changed by changing the thicknesses of the slinger (11a) and the magnetic rubber molded product (12a) from the example shown in FIG. It may be extended or shortened.
  • FIG. 4 shows another example of the sealing device (12).
  • the sealing device (11) shown in FIG. 3 The difference from the sealing device (11) shown in FIG. 3 is that the slinger (11b) of the first member (1b) is folded back to the second member (2a) side and extends in the direction of the rotation axis (L). It is the point which has.
  • the 1st member (1b) and the 2nd member (2a) further form the labyrinth structure part (L2) which opposes perpendicularly to the axis of rotation (L), the rubber molded product (22a), It is a point which forms a labyrinth structure part (R2) facing the 1st member (1b).
  • the labyrinth structure portion (R2) is formed such that the rubber molded product (22a) and the portion of the magnetic rubber molded product (12b) covering the tip of the folded portion T are opposed to each other.
  • the first member and the first member (1b) and the second member (2a) further form a labyrinth structure portion (R2) that is perpendicular to the direction of the rotation axis (L). Therefore, it is difficult for foreign matter such as muddy water to enter the space (S) as compared with the sealing device (11) shown in FIG. From the viewpoint of further preventing intrusion of foreign matter, the rubber molded product (22a) faces the first member (1b) to form a labyrinth structure (R2).
  • the width (d2) of the gap is usually 0.1 to 1.0 mm.
  • the labyrinth structure part (R2) extends in a direction intersecting with the direction in which the labyrinth structure part (R1) extends
  • the length is not particularly limited, but is usually 0.5 mm or more. Therefore, the length of the labyrinth structure part (R2) can be extended by changing the thickness of the part of the magnetic rubber molded product (12b) covering the tip part of the folded part T from the example shown in FIG. Or it may be shortened.
  • Nitrile rubber “NBR” “Nipol 1042” manufactured by Nippon Zeon Co., Ltd. (Acrylonitrile content 33.5%, Mooney viscosity (ML 1 + 10 , 100 ° C.) 77.5) ⁇ "Ketjen Black EC-600JD” manufactured by Conductive Carbon Black Lion Co., Ltd. DBP oil absorption: 495mL / 100g ⁇ Carbon Black Tokai Carbon Co., Ltd. FEF (Fast Extruding Furnace) carbon "Seast SO” DBP oil absorption: 115mL / 100g
  • Stearic acid (lubricant) NOF Corporation “Stearic acid cherry” -"Zinc oxide type 1" manufactured by Zinc Oxide ⁇ Plasticizer Adepic acid ether plasticizer "ADEKA SIZER RS-107” manufactured by ADEKA ⁇ Vulcanization accelerator (MBTS) 2,2'-Dibenzothiazolyl disulfide (MBTS) "Sunseller DM” manufactured by Sanshin Chemical Industry Co., Ltd. ⁇ Vulcanization accelerator (TETD) Tetraethylthiuram disulfide (TETD) "Sunseller TET-G” manufactured by Sanshin Chemical Industry Co., Ltd. ⁇ Sulfur Hosoi Chemical Co., Ltd. “fine sulfur 500 mesh”
  • Example 1 (Production of vulcanized rubber sheet) A mixture having the following composition was kneaded for 60 minutes at a temperature of 40 ° C. using an open roll to prepare an unvulcanized rubber sheet having a thickness of 2.0 to 3.0 mm. The obtained unvulcanized rubber sheet was press vulcanized at 150 ° C. for 10 minutes to obtain a vulcanized rubber sheet having a length (long side) 20 mm ⁇ width (short side) 15 mm ⁇ thickness 2 mm (hereinafter referred to as rubber). Abbreviated as sheet).
  • -NBR 100 parts by mass-Conductive carbon black: 8 parts by mass-FEF carbon black: 25 parts by mass-Clay A: 30 parts by mass-Stearic acid: 1 part by mass-Zinc oxide: 5 parts by mass-Plasticizer: 10 parts by mass Parts ⁇ Vulcanization accelerator (MBTS): 2 parts by mass ⁇ Vulcanization accelerator (TETD): 1.5 parts by mass ⁇ Sulfur 1.5 parts by mass
  • the obtained sealing member 2B includes a cored bar 3A and a rubber molded product 4B bonded to the cored bar 3B. Further, a part of the surface of the cored bar 3B is exposed to the outside, and the rubber molded product 4B has lip portions 5d to 5f. This seal member can then be mounted on a rolling bearing.
  • Examples 2 to 4 and Comparative Example 1 A rubber sheet and a sealing member were obtained in the same manner as in Example 1 except that the types and amounts of the components were changed as shown in Table 1 in the above-mentioned “Preparation of vulcanized rubber sheet” and “Preparation of sealing member”. And evaluation similar to Example 1 was performed. The results are shown in Table 1.
  • Example 5 (Production of sealing device) A mold was prepared, and a ring-shaped core metal (cold rolled steel sheet) was put therein. Then, the unvulcanized rubber sheet of Example 1 was placed on the cored bar and pressed at 150 ° C. for 10 minutes at 150 kgf / cm 2 to perform vulcanization molding. Thus, the 2nd member (2a) by which the surface of the ring-shaped metal core 21a was coat
  • NBR polymer JSR N237H
  • Strontium-ferrite Compressed density 3.1 g / cm 3
  • Stearic acid 1 part by mass
  • Microcrystalline wax HIMIC 1070
  • Polyester Plasticizer Polycizer W320
  • Mercaptopropyltrimethoxysilane 1 part by mass
  • Sulfur 0.5 part by mass
  • Active zinc white 4 parts by mass
  • Diphenylamine 2 parts by mass
  • N-cyclohexylbenzothiazyl 2-sulfenamide 1.5 parts by mass Tetramethylthiuram disulfide: 2 parts by mass
  • a ring-shaped L-shaped section made of SUS430 was prepared as a slinger (11a).
  • a ring-shaped mold was prepared, and a slinger (11a) was put therein.
  • the obtained unvulcanized magnetic rubber sheet is placed on the slinger (11a) and pressed at 150 ° C. for 10 minutes at 150 kgf / cm 2 to perform vulcanization molding.
  • the magnetic rubber molding is performed on the slinger (11a).
  • attached was obtained.
  • the sealing device (11) shown in FIG. 3 was produced using the 2nd member (2a) and the 1st member (1a).
  • the width (d1) of the gap in the sealing device (11) shown in FIG. 3 is 0.4 mm.
  • Example 6 As shown in FIG. 4, the sealing device (12) was produced in the same manner as in Example 5 except that the slinger (11b) of the first member (1b) was changed to one having the folded portion (T). A muddy water test was conducted. The results are shown in Table 2. In the sealing device (12) shown in FIG. 4, the width (d1) of the gap is 0.4 mm, and the width (d2) of the gap is 0.4 mm.
  • Comparative Example 2 A sealing device was produced in the same manner as in Example 5 except that the second member was produced using the rubber composition described in Comparative Example 1 in Table 1. And the muddy water test was done like Example 5. The results are shown in Table 2.
  • Comparative Example 3 A sealing device was produced in the same manner as in Example 6 except that the second member was produced using the rubber composition described in Comparative Example 1 in Table 1. And the muddy water test was done like Example 5. The results are shown in Table 2.

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  • Chemical & Material Sciences (AREA)
  • Medicinal Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Sealing With Elastic Sealing Lips (AREA)
  • Sealing Devices (AREA)
  • Sealing Material Composition (AREA)

Abstract

La présente invention concerne un objet moulé en caoutchouc obtenu par vulcanisation d'une composition de caoutchouc qui contient 100 parties en masse d'un caoutchouc nitrile (A), 1-30 parties en masse d'un noir de carbone électriquement conducteur (B) présentant une quantité d'absorption d'huile DBP de 150 à 1000 ml/100 g et 5-60 parties en masse d'une argile silylée (C). Il est préférable que la composition de caoutchouc contienne en outre 5-50 parties en masse d'un noir de carbone (D) présentant une quantité d'absorption d'huile DBP qui n'est pas inférieure à 30 ml/100 g et qui est inférieure à 150 ml/100 g. Suite à cette configuration, il est possible d'obtenir un objet moulé en caoutchouc présentant une excellente conductivité électrique et une excellente résistance aux intempéries.
PCT/JP2016/074717 2015-08-24 2016-08-24 Composition de caoutchouc, objet moulé en caoutchouc et procédé pour sa production WO2017033986A1 (fr)

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JP2020079615A (ja) * 2018-11-13 2020-05-28 内山工業株式会社 密封装置
CN111465788A (zh) * 2017-12-27 2020-07-28 Nok株式会社 密封装置
JP2020152796A (ja) * 2019-03-19 2020-09-24 内山工業株式会社 軸受用シール部材及びその製造方法
JP2021099135A (ja) * 2019-12-23 2021-07-01 中西金属工業株式会社 回転用シール
JP2021099136A (ja) * 2019-12-23 2021-07-01 中西金属工業株式会社 回転用シール
CN113105677A (zh) * 2021-04-06 2021-07-13 浙江固耐橡塑科技有限公司 一种用于电机轴承的导电密封材料
WO2022080076A1 (fr) * 2020-10-14 2022-04-21 ミネベアミツミ株式会社 Roulement à rouleaux
CN116419946A (zh) * 2020-11-16 2023-07-11 Nok株式会社 丁腈橡胶系组合物

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CN111465788A (zh) * 2017-12-27 2020-07-28 Nok株式会社 密封装置
JP2020079615A (ja) * 2018-11-13 2020-05-28 内山工業株式会社 密封装置
JP7249008B2 (ja) 2018-11-13 2023-03-30 内山工業株式会社 密封装置
CN111718552B (zh) * 2019-03-19 2022-11-01 内山工业株式会社 轴承用密封部件和其制造方法
US11371611B2 (en) * 2019-03-19 2022-06-28 Uchiyama Manufacturing Corp. Seal member for bearing and production method therefor
CN111718552A (zh) * 2019-03-19 2020-09-29 内山工业株式会社 轴承用密封部件和其制造方法
JP2020152796A (ja) * 2019-03-19 2020-09-24 内山工業株式会社 軸受用シール部材及びその製造方法
JP7253781B2 (ja) 2019-03-19 2023-04-07 内山工業株式会社 軸受用シール部材及びその製造方法
JP2021099135A (ja) * 2019-12-23 2021-07-01 中西金属工業株式会社 回転用シール
JP2021099136A (ja) * 2019-12-23 2021-07-01 中西金属工業株式会社 回転用シール
WO2022080076A1 (fr) * 2020-10-14 2022-04-21 ミネベアミツミ株式会社 Roulement à rouleaux
CN116419946A (zh) * 2020-11-16 2023-07-11 Nok株式会社 丁腈橡胶系组合物
CN116419946B (zh) * 2020-11-16 2024-03-12 Nok株式会社 丁腈橡胶系组合物
CN113105677A (zh) * 2021-04-06 2021-07-13 浙江固耐橡塑科技有限公司 一种用于电机轴承的导电密封材料

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