WO2015198537A1 - Regenerated rubber, process for producing same, and transmission belt including same - Google Patents

Regenerated rubber, process for producing same, and transmission belt including same Download PDF

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Publication number
WO2015198537A1
WO2015198537A1 PCT/JP2015/002833 JP2015002833W WO2015198537A1 WO 2015198537 A1 WO2015198537 A1 WO 2015198537A1 JP 2015002833 W JP2015002833 W JP 2015002833W WO 2015198537 A1 WO2015198537 A1 WO 2015198537A1
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WO
WIPO (PCT)
Prior art keywords
rubber
mass
recycled
transmission belt
crosslinked
Prior art date
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PCT/JP2015/002833
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French (fr)
Japanese (ja)
Inventor
公睦 大野
博之 橘
Original Assignee
バンドー化学株式会社
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Application filed by バンドー化学株式会社 filed Critical バンドー化学株式会社
Priority to CN201580033659.XA priority Critical patent/CN106459540A/en
Priority to JP2016529009A priority patent/JPWO2015198537A1/en
Publication of WO2015198537A1 publication Critical patent/WO2015198537A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L23/16—Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
    • C08L23/26—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment
    • C08L23/32—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers modified by chemical after-treatment by reaction with compounds containing phosphorus or sulfur
    • 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
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G1/00—Driving-belts
    • F16G1/06—Driving-belts made of rubber
    • 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
    • F16G—BELTS, CABLES, OR ROPES, PREDOMINANTLY USED FOR DRIVING PURPOSES; CHAINS; FITTINGS PREDOMINANTLY USED THEREFOR
    • F16G5/00—V-belts, i.e. belts of tapered cross-section
    • F16G5/04—V-belts, i.e. belts of tapered cross-section made of rubber
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention relates to recycled rubber, a method for producing the same, and a transmission belt using the same.
  • Recycled rubber is made into a state where it can be molded again by applying chemical treatment or physical treatment to the crosslinked rubber of used rubber products.
  • the use of recycled rubber is extremely effective in reducing the material cost and manufacturing cost of rubber products.
  • Patent Document 1 discloses a method for producing a recycled rubber in which a crosslinked rubber is subjected to a desulfurization treatment under conditions of a temperature of 180 to 350 ° C. and a shear stress of 10 to 150 kg / cm 2 .
  • Patent Document 2 discloses a method for producing a reclaimed rubber in which a shearing stress is applied to a crosslinked rubber at a heating temperature equal to or higher than the regenerating temperature at which a break such as cross-linking between the rubber molecules occurs.
  • Patent Document 3 discloses a method for producing a reclaimed rubber in which a raw material powder of a crosslinked rubber and a diene rubber are mixed and a shear stress of a maximum shear rate of 300 / sec or more is applied thereto.
  • Patent Document 4 discloses a method for producing a recycled rubber in which a crosslinked rubber is subjected to a desulfurization treatment under conditions of a temperature of 220 to 350 ° C. and a shear stress of 10 to 150 kg / cm 2 .
  • the recycled rubber of the present invention contains ethylene propylene diene monomer as a rubber component and has a gel fraction of 50 to 85% by mass.
  • the method for producing a reclaimed rubber according to the present invention has a gel fraction of 50 to 85% by mass in which a crosslinked rubber containing sulfur-crosslinked ethylene propylene diene monomer is pulverized and subjected to desulfurization treatment by applying shear stress to the crushed crosslinked rubber. It is.
  • At least a part of the belt main body is made of a rubber composition using the recycled rubber of the present invention.
  • FIG. 1 is a perspective view of a piece of a wrapped V belt according to Embodiment 1.
  • FIG. It is the 1st explanatory view showing the manufacturing method of the wrapped V belt concerning an embodiment.
  • It is 2nd explanatory drawing which shows the manufacturing method of the wrapped V belt which concerns on embodiment.
  • It is 3rd explanatory drawing which shows the manufacturing method of the wrapped V belt which concerns on embodiment.
  • It is a 5th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment.
  • It is a 7th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment.
  • the recycled rubber according to Embodiment 1 is derived from a rubber composition containing sulfur-crosslinked ethylene propylene diene monomer (hereinafter referred to as “EPDM”), and has a high gel fraction of 50 to 85 mass%.
  • EPDM sulfur-crosslinked ethylene propylene diene monomer
  • the recycled rubber according to Embodiment 1 is derived from sulfur-crosslinked EPDM, and the gel fraction resulting from the sulfur crosslinking is as high as 50 to 85% by mass. Therefore, the rubber composition using the recycled rubber has high rubber elasticity. At the same time, tan ⁇ is low. Therefore, it is preferable that at least a part of the belt main body of the transmission belt that is bent repeatedly is constituted by the rubber composition using the recycled rubber according to the first embodiment.
  • the gel fraction of the reclaimed rubber according to Embodiment 1 is preferably 50% by mass or more, more preferably from the viewpoint of being easy to re-crosslink, suppressing deterioration of physical properties and obtaining excellent processability. Is 65% by mass or more, preferably 85% by mass or less, more preferably 80% by mass or less.
  • the recycled rubber according to Embodiment 1 includes a rubber component and other rubber compounding agents.
  • the content of the rubber component in the recycled rubber according to Embodiment 1 is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less. .
  • the content of EPDM in the rubber component of the recycled rubber according to Embodiment 1 is preferably 50% by mass or more, more preferably 70% by mass or more.
  • the content of EPDM in the rubber component of the recycled rubber is most preferably 100% by mass, that is, the rubber component of the recycled rubber is most preferably only EPDM.
  • Examples of rubber components other than EPDM that can be included in the recycled rubber according to Embodiment 1 include ethylene- ⁇ -olefin elastomers other than EPDM such as ethylene propylene rubber (EPM), natural rubber (NR), and the like. .
  • EPM ethylene propylene rubber
  • NR natural rubber
  • a rubber compounding agent contained in the recycled rubber according to Embodiment 1 for example, a reinforcing material such as carbon black, a softening agent, a processing aid, a vulcanization acceleration aid, and a crosslinking agent, which have been contained before the desulfurization treatment described later.
  • Agents, vulcanization accelerators, anti-aging agents and the like for example, a reinforcing material such as carbon black, a softening agent, a processing aid, a vulcanization acceleration aid, and a crosslinking agent, which have been contained before the desulfurization treatment described later.
  • the recycled rubber according to the first embodiment is blended with virgin rubber to be a base rubber material, or is used as it is as a base rubber material, and various rubber compounding agents including a crosslinking agent are blended therein.
  • a transmission belt It is used as a rubber composition constituting rubber products such as conveyor belts, tires and hoses. As described above, among these, it is particularly suitable for a transmission belt.
  • the recycled rubber according to Embodiment 1 can be obtained by taking out a crosslinked rubber (crosslinked rubber composition) from a used rubber product and desulfurizing the crosslinked rubber by a predetermined method.
  • the recycled rubber according to Embodiment 1 is obtained by previously pulverizing a crosslinked rubber containing sulfur-crosslinked EPDM into a powdery or granular form, and then applying the powdered or granular crosslinked rubber to a predetermined processing temperature. It is obtained by applying a shearing stress at desulfurization treatment.
  • the gel fraction of the recycled rubber can be controlled by a combination of conditions such as the processing temperature, shear stress, and processing time during the desulfurization process.
  • the regenerated rubber obtained by the desulfurization treatment in this way has a crosslinkable EPDM by cutting a part of the sulfur crosslinking point and the main chain of the EPDM, and the EPDM of the elastic rubber for the gel due to the remaining sulfur crosslinking.
  • the rubber composition using this the rubber elasticity is high and the tan ⁇ is low as compared with the case where only the virgin rubber is used.
  • examples of the used rubber product include a transmission belt, a conveyor belt, a tire, and a hose.
  • the average particle diameter of the powdery or granular crosslinked rubber is preferably 10 ⁇ m or more, more preferably 100 ⁇ m or more, and preferably 5 mm or less, more preferably 3 mm or less.
  • the treatment temperature of the desulfurization treatment is 150 to 250 ° C., and preferably 180 ° C. or more and preferably 230 ° C. or less from the viewpoint of the balance between the desulfurization and the remaining gel content.
  • the shear stress during the desulfurization treatment is preferably 0.981 MPa or more, more preferably 4 MPa or more, and preferably 20 MPa or less, more preferably 15 MPa or less, from the viewpoint of the balance between the desulfurization and the residual gel content. is there.
  • the desulfurization treatment as described above can be performed using known processing equipment such as a single-screw or twin-screw extruder.
  • the recycled rubber according to Embodiment 1 may contain a dispersion of a thermoplastic resin compounding material having a maximum particle size of 250 ⁇ m or less.
  • a rubber composition obtained from a recycled rubber containing a dispersion material of a thermoplastic resin having a maximum particle size of 250 ⁇ m or less has a low tan ⁇ , so that heat generation is suppressed even when it is repeatedly bent. It is suitable for application to rubber products that are repeatedly bent such as a transmission belt.
  • thermoplastic resin examples include blending materials such as polyamide resin (PA), polyethylene terephthalate resin (PET), and polypropylene resin (PP).
  • PA polyamide resin
  • PET polyethylene terephthalate resin
  • PP polypropylene resin
  • PA polyamide resin
  • the compounding material of the thermoplastic resin may be composed of a single type or a plurality of types.
  • the form of the blended material of the thermoplastic resin include powdery, granular, and fibrous forms. Of these, fibrous fibers, particularly short fibers having a fiber diameter of 10 to 30 ⁇ m and a fiber length of 1 to 5 mm are preferred.
  • the maximum particle size of the thermoplastic resin compounding material is preferably 230 ⁇ m or less, more preferably 205 ⁇ m or less, and even more preferably from the viewpoint of suppressing the occurrence of cracks at the interface of the thermoplastic resin compounding material in the obtained recycled rubber. It is 155 ⁇ m or less, more preferably 150 ⁇ m or less, preferably 5 ⁇ m or more, more preferably 20 ⁇ m or more, still more preferably 50 ⁇ m or more, and even more preferably 100 ⁇ m or more.
  • the maximum particle size of the thermoplastic resin compounding material in the recycled rubber can be controlled by the shear stress or the like in the desulfurization process. The maximum particle size of the thermoplastic resin compounding material can be measured by observing the surface of the obtained recycled rubber.
  • the content of the compounding material of the thermoplastic resin in the recycled rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less. Further, when producing a recycled rubber containing a thermoplastic resin having a maximum particle size of 250 ⁇ m or less, the treatment temperature in the desulfurization treatment is set to a temperature that is 20 ° C. or more lower than the melting point of the thermoplastic resin compounding material. Is preferred.
  • FIG. 1 shows a wrapped V-belt B (power transmission belt) according to the first embodiment.
  • the wrapped V belt B according to the first embodiment is used for, for example, an agricultural machine or an industrial machine.
  • the dimensions of the wrapped V-belt B according to the first embodiment are not particularly limited, and are, for example, a belt circumferential length of 700 to 5000 mm, a belt width of 16 to 17 mm, and a belt thickness of 8 to 10 mm.
  • the wrapped V-belt B according to the first embodiment is configured in a triple layer of a compression rubber layer 11 on the belt inner peripheral side (pulley contact side), an intermediate adhesive rubber layer 12 and a stretched rubber layer 13 on the belt outer peripheral side.
  • the belt body 10 having a trapezoidal cross-sectional shape is provided.
  • a core wire 14 is embedded in the adhesive rubber layer 12 so as to form a spiral having a pitch in the belt width direction.
  • the belt body 10 is entirely covered with a reinforcing cloth 15.
  • the compressed rubber layer 11, the adhesive rubber layer 12, and the stretch rubber layer 13 are all composed of a crosslinked rubber composition. At least one of the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is composed of a rubber composition that is cross-linked using the reclaimed rubber according to the first embodiment.
  • the rubber composition constituting the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is preferably made of the reclaimed rubber according to the first embodiment, and in that case, the same rubber is used. It may be a composition.
  • the rubber composition using the reclaimed rubber according to the first embodiment may use the reclaimed rubber according to the first embodiment as a base rubber material, and virgin rubber is blended as a rubber component to the base rubber. It may be used as a material.
  • the virgin rubber is preferably an ethylene- ⁇ -olefin elastomer, and more preferably EPDM.
  • the content of virgin rubber in the rubber component of the rubber composition is preferably 20% by mass or more, preferably 80% by mass or less, more preferably 60% by mass or less.
  • various rubber compounding agents are blended in addition to the rubber compounding agent contained in the recycled rubber according to the first embodiment.
  • rubber compounding agents include reinforcing materials such as carbon black, softeners, processing aids, vulcanization acceleration aids, crosslinking agents, vulcanization accelerators, and antiaging agents.
  • the reinforcing material may not be blended when the recycled rubber according to Embodiment 1 includes the reinforcing material.
  • the reinforcing material is preferably blended when the rubber composition containing the recycled rubber according to Embodiment 1 contains virgin rubber.
  • a reinforcing material for example, carbon black, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like.
  • Silica is also mentioned as a reinforcing agent.
  • the reinforcing agent may be composed of a single species or a plurality of species.
  • the content of the reinforcing material is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition, from the viewpoint of a balance between wear resistance and bending resistance.
  • the softener examples include petroleum softeners, mineral oil softeners such as paraffin wax, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, fallen raw oil, waxy wax, rosin And vegetable oil-based softeners such as pine oil.
  • the softener may be composed of a single species or a plurality of species.
  • the content of the softening agent is, for example, 2 to 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
  • processing aids include stearic acid, polyethylene wax, and fatty acid metal salts.
  • the processing aid may be composed of a single species or a plurality of species.
  • the content of the processing aid is, for example, 0.1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
  • the vulcanization acceleration aid examples include metal oxides such as magnesium oxide and zinc oxide (zinc white), metal carbonates, fatty acids and derivatives thereof.
  • the vulcanization acceleration aid may be composed of a single species or a plurality of species.
  • the content of the vulcanization acceleration aid is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
  • crosslinking agent examples include sulfur and organic peroxides.
  • sulfur may be blended, an organic peroxide may be blended, or both of them may be used in combination.
  • the compounding amount of the crosslinking agent is, for example, 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, and the rubber component 100 of the rubber composition in the case of organic peroxide. For example, 0.5 to 8.0 parts by mass with respect to parts by mass.
  • organic peroxide examples include dialkyl peroxides such as dicumyl peroxide, peroxyesters such as t-butyl peroxyacetate, and ketone peroxides such as dicyclohexanone peroxide.
  • dialkyl peroxides such as dicumyl peroxide, peroxyesters such as t-butyl peroxyacetate, and ketone peroxides such as dicyclohexanone peroxide.
  • the organic peroxide may be a single species or a plurality of species.
  • the rubber composition When the crosslinking agent is sulfur, the rubber composition includes a gel component due to residual sulfur crosslinking and a sulfur bond derived from additional sulfur crosslinking.
  • the crosslinking agent is an organic peroxide, residual rubber crosslinking And a C—C bond derived from organic peroxide crosslinking. Therefore, by using the recycled rubber according to Embodiment 1, a rubber composition having more crosslinking points can be obtained as compared with a rubber composition using only EPDM virgin rubber.
  • the vulcanization accelerator examples include thiazole type (eg MBT, MBTS etc.), thiuram type (eg TT, TRA etc.), sulfenamide type (eg CZ etc.), dithiocarbamate type (eg BZ-P etc.) And the like.
  • the vulcanization accelerator may be composed of a single species or a plurality of species.
  • sulfur is used as the crosslinking agent, a vulcanization accelerator is preferably added. In that case, it is preferable to use a thiazole vulcanization accelerator and a thiuram vulcanization accelerator in combination.
  • the content of the vulcanization accelerator is, for example, 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
  • Antiaging agents include amine-based, quinoline-based, hydroquinone derivatives, phenol-based and phosphite-based agents.
  • the anti-aging agent may be composed of a single species or a plurality of species.
  • the content of the anti-aging agent is, for example, 0 to 8 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
  • layered silicates such as smectite group, vermulite group, kaolin group and the like may be blended.
  • the loss coefficient tan ⁇ at 100 ° C. in the line direction of the rubber composition using the recycled rubber according to Embodiment 1 is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0. .15 or less, more preferably 0.12 or less.
  • the loss coefficient tan ⁇ is obtained based on JISK6394.
  • the core wire 14 is composed of twisted yarns such as polyester fiber (PET), polyethylene naphthalate fiber (PEN), aramid fiber, vinylon fiber and the like.
  • PET polyester fiber
  • PEN polyethylene naphthalate fiber
  • aramid fiber vinylon fiber and the like.
  • an adhesive treatment for heating after being immersed in an RFL aqueous solution before molding and / or an adhesive treatment for drying after being immersed in rubber paste is performed.
  • the reinforcing cloth 15 is made of, for example, a woven fabric, a knitted fabric, a non-woven fabric, or the like formed of yarns such as cotton, polyamide fiber, polyester fiber, and aramid fiber.
  • the reinforcing cloth 15 is coated with rubber paste on the surface on the side of the belt main body 10 and / or an adhesive treatment in which it is immersed in an RFL aqueous solution and heated before molding. Adhesive treatment for drying is applied.
  • a rubber sheet 11 ′ for the compression rubber layer, a rubber sheet 12 ′ for the adhesive rubber layer, a rubber sheet 13 ′ for the stretch rubber layer, a twisted yarn 14 ′ for the core wire, and a cloth 15 ′ for the reinforcing cloth prepare.
  • those including the recycled rubber according to the first embodiment are the first embodiment.
  • An uncrosslinked rubber composition obtained by kneading the recycled rubber and the rubber compounding agent is obtained by processing into a sheet shape using a calender roll or the like.
  • the twisted yarn 14 ′ for the core wire and the fabric 15 ′ for the reinforcing fabric are subjected to adhesion treatment.
  • the rubber sheet 11 'for the compression rubber layer is wound around the mantle 21 a plurality of times, and the rubber sheet 12' for the adhesive rubber layer is wound thereon. Further, as shown in FIG. 2B, the twisted yarn 14 'is wound in a spiral shape. Further thereon, as shown in FIG. 2C, a rubber sheet 12 'for the adhesive rubber layer and a rubber sheet 13' for the stretch rubber layer are wound in order to produce a cylindrical laminated structure 10 '.
  • the cylindrical laminated structure 10 ′ is cut into a predetermined width on the mantle 21 and then removed from the mantle 21.
  • the annular laminated structure 10 ' is wound around a pair of pulleys with the rubber sheet 11' side for the compressed rubber layer facing outward and rotated.
  • the volume is adjusted by obliquely cutting both sides of the laminated portion of the sheet 11 ′ into a V shape.
  • the lapped annular laminated structure 10 ' is fitted into the groove 23 of the cylindrical mold 22, and it is placed in a vulcanizing can and heated and pressurized.
  • the rubber component of the annular laminated structure 10 ′ is cross-linked to form the belt main body 10
  • the twisted yarn 14 ′ is bonded and integrated to the belt main body 10 to form the core wire 14, and the cloth 15 ′ is the belt main body.
  • the wrapped V-belt B according to the first embodiment is manufactured by being bonded and integrated with 10 to form the reinforcing cloth 15.
  • examples of the used rubber product include a transmission belt, a conveyor belt, a tire, and a hose.
  • Examples of rubber components contained in the crosslinked rubber include natural rubber (NR), EPDM and EPM ethylene- ⁇ -olefin elastomers, chloroprene rubber (CR), hydrogenated nitrile rubber (H-NBR), and isoprene rubber (IR). Styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR) and the like.
  • the rubber component contained in the crosslinked rubber may be composed of a single species or a plurality of species.
  • the content of the rubber component in the crosslinked rubber is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less.
  • carbon black In addition to the crosslinked rubber, carbon black, a filler, an anti-aging agent, a plasticizer, and the like may be blended.
  • the rubber component is crosslinked, but it may be crosslinked by sulfur or by an organic peroxide.
  • the crosslinked rubber before the desulfurization treatment is preferably pulverized and powdery or granular from the viewpoint of efficiently performing the desulfurization treatment.
  • the average particle size of the powdery or granular crosslinked rubber is preferably 10 ⁇ m or more, more preferably 100 ⁇ m or more, still more preferably 200 ⁇ m or more, and preferably 5 mm or less, more preferably 3 mm or less.
  • thermoplastic resin examples include blending materials such as polyamide resin (PA), polyethylene terephthalate resin (PET), and polypropylene resin (PP).
  • PA polyamide resin
  • PET polyethylene terephthalate resin
  • PP polypropylene resin
  • PA polyamide resin
  • the compounding material of the thermoplastic resin may be composed of a single type or a plurality of types.
  • the form of the blended material of the thermoplastic resin include powdery, granular, and fibrous forms. Of these, fibrous fibers, particularly short fibers having a fiber diameter of 10 to 30 ⁇ m and a fiber length of 1 to 5 mm are preferred.
  • the compounding material of the thermoplastic resin is contained in the crosslinked rubber, that is, present in a place where the crosslinked rubber is pre-dispersed and compounded in the crosslinked rubber taken out from the used rubber product, whereby shearing is applied to the crosslinked rubber.
  • the content of the thermoplastic resin compounding material in the crosslinked rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less. It is.
  • the compounding material of the thermoplastic resin is not contained in the crosslinked rubber, and may be present in a place where the crosslinked rubber is mixed with the crosslinked rubber during the desulfurization treatment and thereby shear is applied to the crosslinked rubber.
  • the desulfurization treatment in the method for producing recycled rubber according to Embodiment 2 is a physical treatment in which shearing stress is applied to the crosslinked rubber to cut or depolymerize the crosslinked portion.
  • examples of the desulfurization treatment method include a method of continuously desulfurizing the crosslinked rubber using a shear flow field reaction tank having a uniaxial or biaxial screw.
  • the process temperature in a desulfurization process is set to the temperature 20 degreeC or more lower than melting
  • the treatment temperature in the desulfurization treatment is the temperature of the object to be treated at the time of the desulfurization treatment.
  • It is the set temperature in the tank.
  • the melting point of the blended material of the thermoplastic resin is, for example, 225 to 235 ° C. in the case of nylon 6 and 260 to 270 ° C. in the case of nylon 66, and is a polyethylene terephthalate resin (PET).
  • PET polyethylene terephthalate resin
  • PP polypropylene resin
  • DSC differential scanning calorimeter
  • the treatment temperature in the desulfurization treatment is, for example, set to 205 ° C. or less in the case of a blended material of nylon 6 having a melting point of 225 ° C., and to 240 ° C. or less in the case of nylon 66 having a melting point of 260 ° C. Set.
  • the treatment temperature in the desulfurization treatment is preferably set to a temperature that is 30 ° C. or more lower than the melting point of the blended material of the thermoplastic resin blended with the crosslinked rubber, from the viewpoint of suppressing deterioration of physical properties in the obtained recycled rubber, 50 ° C.
  • the temperature is set to 20 ° C. or lower than the lowest melting point among these melting points.
  • the shear stress in the desulfurization treatment is preferably set to 1 MPa or more, more preferably set to 4 MPa or more from the viewpoint of appropriately performing the desulfurization treatment, and the effect of the blended material of the thermoplastic resin is diluted. From the viewpoint of regulating the operation, it is preferably set to 20 MPa or less, and more preferably set to 15 MPa or less.
  • thermoplastic resin compounding material includes the above-mentioned polyamide resins (PA) and the like, and examples of the form include powdery, granular, fibrous and the like.
  • PA polyamide resins
  • the other thermoplastic resin compounding material may be the same as or different from the thermoplastic resin compounding material contained in the crosslinked rubber.
  • the compounded material of the thermoplastic resin is cut by shearing in the desulfurization process and dispersed to be reduced in particle size.
  • the reclaimed rubber obtained after the desulfurization process the same rubber as the crosslinked rubber In the component, a compounding material of a thermoplastic resin having a maximum particle size of 250 ⁇ m or less is dispersed and contained.
  • a thermoplastic resin compounding material having a maximum particle size of more than 250 ⁇ m is no longer a foreign substance and may cause cracks.
  • the maximum particle size of the thermoplastic resin compounding material is preferably 230 ⁇ m or less, more preferably 205 ⁇ m or less, and even more preferably from the viewpoint of suppressing the occurrence of cracks at the interface of the thermoplastic resin compounding material in the obtained recycled rubber. It is 155 ⁇ m or less, more preferably 150 ⁇ m or less, preferably 5 ⁇ m or more, more preferably 20 ⁇ m or more, still more preferably 50 ⁇ m or more, and even more preferably 100 ⁇ m or more.
  • the maximum particle size of the thermoplastic resin compounding material in the recycled rubber can be controlled by the shear stress or the like in the desulfurization process. The maximum particle size of the thermoplastic resin compounding material can be measured by observing the surface of the obtained recycled rubber.
  • the content of the rubber component in the recycled rubber is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less.
  • the content of the thermoplastic resin compounding material in the recycled rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less.
  • the processing temperature at the time of desulfurization treatment by applying a shear stress to the crosslinked rubber in the presence of the thermoplastic resin compounding material is set to be the same as that of the thermoplastic resin compounding material.
  • the temperature is set to 20 ° C. or more lower than the melting point, and a recycled rubber containing a thermoplastic resin compounding material having a maximum particle size of 250 ⁇ m or less is dispersed and contained. Therefore, the rubber composition obtained from the recycled rubber obtained has a low tan ⁇ as shown in the test evaluation 2 of the following examples, so that heat generation is suppressed even when it is repeatedly bent.
  • a recycled rubber suitable for application to a rubber product that undergoes repeated bending, such as a transmission belt, can be produced.
  • the blended material of thermoplastic resin such as short fibers contained in the raw material crosslinked rubber is usually separated as a foreign substance by sieving or an air floating table.
  • the blended material of the thermoplastic resin contributes to the reduction in tan ⁇ in the rubber composition using the obtained recycled rubber.
  • the recycled rubber obtained by the production method of Embodiment 2 may have the same configuration as the recycled rubber according to Embodiment 1, that is, derived from a rubber composition containing a sulfur-crosslinked ethylene propylene diene monomer. And the gel fraction may be 50 to 85% by mass.
  • the reclaimed rubber obtained by the production method of Embodiment 2 is blended with the same or different virgin rubber as contained in the reclaimed rubber to form a base rubber material as in Embodiment 1, or as it is with the base rubber material as it is. Then, a rubber compounding agent containing a crosslinking agent is compounded, and for example, a rubber constituting a rubber product such as a transmission belt such as a wrapped V belt B shown in FIG. 1 in Embodiment 1, a conveyor belt, a tire, a hose, etc. Used as a composition.
  • the recycled rubber obtained by the production method of Embodiment 2 has a low tan ⁇ rubber composition using the rubber, so that heat generation can be suppressed even when it is repeatedly bent. Therefore, it is preferable that at least a part of the belt body of the transmission belt bent repeatedly is constituted by the rubber composition using the recycled rubber obtained by the manufacturing method of Embodiment 2.
  • the storage elastic modulus E ′ at 25 ° C. in the line direction of the rubber composition using the recycled rubber obtained by the production method of Embodiment 2 is preferably 12 MPa or more, more preferably 15 MPa or more, Preferably it is 70 MPa or less, More preferably, it is 40 MPa or less.
  • the storage elastic modulus E ′ at 100 ° C. is preferably 8 MPa or more, more preferably 10 MPa or more, and preferably 50 MPa or less, more preferably 30 MPa or less.
  • the storage elastic modulus E ′ at 120 ° C. is preferably 7 MPa or more, more preferably 9 MPa or more, and preferably 50 MPa or less, more preferably 25 MPa or less.
  • the loss factor tan ⁇ at 25 ° C. in the row direction of the recycled rubber obtained by the production method of Embodiment 2 is preferably 0.06 or more, more preferably 0.08 or more, and preferably 0.20. Below, more preferably 0.18 or less.
  • the loss coefficient tan ⁇ at 100 ° C. is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0.15 or less, more preferably 0.12 or less.
  • the loss coefficient tan ⁇ at 120 ° C. is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0.14 or less, more preferably 0.11 or less.
  • the storage elastic modulus E ′ and the loss coefficient tan ⁇ are obtained based on JISK6394.
  • a recycled rubber 1 having a gel fraction of 70% by mass at a treatment temperature of 200 ° C. and a screw rotation speed of 400 rpm (shear stress of 7 MPa) was obtained.
  • a recycled rubber 2 having a gel fraction of 52% by mass was obtained at a treatment temperature of 220 ° C. and a screw rotation speed of 400 rpm (shear stress of 8 MPa).
  • a recycled rubber 3 having a gel fraction of 45% by mass was obtained at a treatment temperature of 260 ° C. and a screw rotation speed of 600 rpm (shear stress of 11 MPa).
  • the gel fraction was determined by the toluene swelling method described above.
  • Example 1-1 For 200 parts by mass of recycled rubber 1 (100 parts by mass of EPDM as a rubber component), 1 part by mass of stearic acid (manufactured by NOF Corporation, trade name: bead stearic acid Tsubaki), zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) Product name: 5 parts by mass of zinc oxide (3 types), softener (made by Idemitsu Kosan Co., Ltd., product name: Diana Process PW-90), 20 parts by mass, sulfur (oil treated sulfur by Karuizawa Smelter), 3 parts by mass, 2 parts by weight of a sulfur accelerator (trade name: Noxeller TET-G manufactured by Ouchi Shinsei Chemical Co., Ltd.) and 1 part by weight of a thiazole vulcanization accelerator (trade name: Noxeller DM-P manufactured by Ouchi Shinsei Chemical Co., Ltd.) An uncrosslinked rubber composition obtained by kneading was designated as Example 1-1.
  • Example 1-2 For 200 parts by mass of recycled rubber 1 (100 parts by mass of EPDM as a rubber component), 1 part by mass of stearic acid, 5 parts by mass of zinc oxide, 20 parts by mass of softening agent, organic peroxide (manufactured by NOF Corporation) Product name: Perbutyl P-40 Purity 40% by mass) An uncrosslinked rubber composition obtained by blending and kneading 8 parts by mass (active ingredient 3.2 parts by mass) was defined as Example 1-2.
  • Example 1-3 An uncrosslinked rubber composition having the same structure as in Example 1 except that the recycled rubber 2 was used was designated as Example 1-3.
  • Example 1-4 50 parts by mass of virgin rubber (trade name: EP33 manufactured by JSR) of EPDM is blended with 100 parts by mass of recycled rubber 1 (EPDM 50 parts by mass of rubber component), and 100 parts by mass of rubber component contained therein,
  • EPDM 50 parts by mass of rubber component 100 parts by mass of recycled rubber 1
  • HAF carbon black trade name: SEAST 3 manufactured by Tokai Carbon Co., Ltd.
  • stearic acid 1 part by mass of stearic acid
  • 5 parts by mass of zinc oxide 20 parts by mass of a softening agent
  • 3 parts by mass of sulfur and thiuram-based vulcanization
  • An uncrosslinked rubber composition obtained by blending 2 parts by mass of an accelerator and 1 part by mass of a thiazole vulcanization accelerator and kneading was designated as Example 1-4.
  • Comparative Example 1-1 A non-crosslinked rubber composition having the same structure as in Example 1 except that the recycled rubber 3 was used was designated as Comparative Example 1-1.
  • Comparative Example 1-2 A non-crosslinked rubber composition having the same structure as in Example 2 except that the recycled rubber 3 was used was designated as Comparative Example 1-2.
  • the rubber compositions of Examples 1-1, 1-3, and 1-4 and Comparative Example 1-1 are sulfur cross-linked systems, the rubber compositions obtained by cross-linking these are residual The gel content due to sulfur cross-linking and the sulfur bond derived from the additional sulfur cross-linking are provided.
  • the rubber compositions of Example 1-2 and Comparative Example 1-2 are organic peroxide crosslinking systems, the rubber composition obtained by crosslinking them has a gel content due to residual sulfur crosslinking. And a C—C bond derived from organic peroxide crosslinking.
  • FIG. 3 shows a pulley layout of the belt running test machine 30.
  • the belt running test machine 30 includes a driving pulley 31 having a pulley diameter of 80 mm and a driven pulley 32 having a pulley diameter of 80 mm provided below the driving pulley 31.
  • the driven pulley 32 is configured to be movable up and down, and by suspending a weight (dead weight) from the driven pulley 32, the driven pulley 32 and the wrapped V-belt B wound around the driven pulley 32 can be loaded with tension. Has been.
  • the belt life was evaluated as a relative value with the belt running time until crack occurrence in Comparative Example 1-1 as 100. Further, the belt temperature during belt running was measured using a non-contact type surface thermometer, and the maximum value of the temperature difference from the ambient temperature was determined.
  • Test evaluation results The test results are shown in Table 1.
  • Example 1-3 of the sulfur crosslinking system using the regenerated rubber 2 having a gel fraction of 52% by mass higher than that of the regenerated rubber 3 tan ⁇ is lower than that in the case of Comparative Example 1-1 (0. 125), and the heat generation during running of the belt was small (+ 29 ° C.), and the belt life was also long (142).
  • Example 1-1 of the sulfur cross-linking system using the regenerated rubber 1 having a gel fraction of 70% by mass higher than that of the regenerated rubber 2 tan ⁇ is much lower than in the case of Example 1-2.
  • the heat generation during belt running was smaller (+ 25 ° C.), and the belt life was longer (149).
  • Example 1-2 of the organic peroxide cross-linking system using the regenerated rubber 1 having a gel fraction of 70% by mass tan ⁇ is much lower than that in Example 1-1 (0.
  • the heat generation during running of the belt was much smaller (+ 21 ° C.), and the belt life was even longer (168).
  • Example 1-4 of the sulfur crosslinking system in which recycled rubber 2 and EPDM virgin rubber were blended tan ⁇ was low (0.119) as compared with Comparative Examples 1-1 and 1-2. Also, the heat generated during belt running was small (+ 28 ° C.), and the belt life was also long (152).
  • Recycled rubbers 1 and 2 used in the rubber compositions of Examples 1-1 to 1-4 were obtained by desulfurization treatment of sulfur-crosslinked EPDM, but achieved performance superior to that of using EPDM virgin rubber. can do.
  • the crosslinked rubber After the crosslinked rubber is pulverized to an average particle size of 400 ⁇ m, it is put into a twin screw extruder (manufactured by Nippon Steel Works, model number: TEX30 ⁇ , screw diameter: 30 mm, screw length: 1785 mm), and the processing temperature is the melting point of nylon 66 short fiber
  • Example 2-1 The recycled rubber of Example 2-1 was cut using a cutter, and observed using a microscope (Keyence Co., Ltd., model number: VHX2000) by magnifying three portions of the cross section by 200 times, as shown in FIG. Such a form was seen, and when the outer diameter (maximum outer diameter) of the largest nylon short fiber was measured by the measurement mode, it was 148 ⁇ m. Moreover, it was 62 mass% when the gel fraction was calculated
  • Example 2-2 A recycled rubber obtained in the same manner as in Example 2-1 except that the screw was rotated at 400 rpm (shear stress: 8 MPa) and subjected to desulfurization treatment by applying shear stress to the crosslinked rubber was obtained as Example 2-2. It was.
  • Example 2-2 For the recycled rubber of Example 2-2, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 202 ⁇ m. Moreover, the gel fraction was 68 mass%.
  • Example 2-3 Except that the treatment temperature was 230 ° C., which is 30 ° C. lower than the melting point of nylon 66 short fiber, 230 ° C., and the screw rotation speed was 600 rpm (shear stress: 12 MPa), and the desulfurization treatment was performed by applying shear stress to the crosslinked rubber.
  • a recycled rubber obtained in the same manner as in Example 2-1 was designated as Example 2-3.
  • Example 2-3 For the recycled rubber of Example 2-3, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and was found to be 151 ⁇ m. Moreover, the gel fraction was 55 mass%.
  • Example 2-4 Example 2-1 except that the crosslinked rubber was subjected to a desulfurization treatment at a treatment temperature of 200 ° C., which is 60 ° C. lower than the melting point of nylon 66 short fiber, 260 ° C., and a screw rotation speed of 200 rpm (shear stress: 6 MPa). Recycled rubber obtained in the same manner as in Example 2-4 was used.
  • Example 2-4 For the recycled rubber of Example 2-4, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 227 ⁇ m. Moreover, the gel fraction was 75 mass%.
  • Example 2-5 Except that the treatment temperature was 240 ° C., which is 20 ° C. lower than the melting point of nylon 66 short fiber of 260 ° C., and the screw rotation speed was 600 rpm (shear stress: 13 MPa). A recycled rubber obtained in the same manner as in Example 2-1 was designated as Example 2-5.
  • Example 2-5 For the recycled rubber of Example 2-5, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 155 ⁇ m. Moreover, the gel fraction was 51 mass%.
  • the gel fraction of the recycled rubber of Comparative Example 2-1 was 78% by mass.
  • the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 147 ⁇ m. Moreover, the gel fraction was 46 mass%.
  • the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 311 ⁇ m. Moreover, the gel fraction was 83 mass%.
  • Example 2-4 The treatment temperature was 250 ° C., which is 10 ° C. lower than the melting point of nylon 66 short fiber, 260 ° C., and the rotational speed of the screw was 100 rpm (shear stress: 4 MPa).
  • a recycled rubber obtained in the same manner as in Example 2-1 was designated as Comparative Example 2-4.
  • the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 302 ⁇ m. Moreover, the gel fraction was 70 mass%.
  • ⁇ Dynamic viscoelasticity test> For the uncrosslinked rubber compositions using the reclaimed rubbers of Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-4, a sheet-like rubber sheet was molded and vulcanized, based on JIS K6394.
  • the storage elastic modulus E ′ and the loss coefficient tan ⁇ were measured at 25 ° C., 100 ° C., and 120 ° C. in the linear direction, with a vibration frequency of 10 Hz and a dynamic strain of 1.0%.
  • Test evaluation results The test results are shown in Tables 4 and 5.
  • Examples 2-1 to 2-5 containing Nylon 66 short fibers and Comparative Examples 2-3 to 2-4 were compared with Comparative Example 2-1 containing no Nylon 66 short fibers.
  • the storage elastic modulus E ′ is high, the loss coefficient tan ⁇ is low, and the belt durability is excellent.
  • Comparative Example 2-2 only the storage elastic modulus E ′ at 25 ° C. is lower than that of Comparative Example 2-1, but otherwise, the storage elastic modulus E ′ is higher than that of Comparative Example 2-1, and the loss. It can be seen that the coefficient tan ⁇ is low and the belt durability is excellent.
  • Comparative Example 2-1 does not contain nylon 66 short fibers, and therefore has a relatively low storage elastic modulus and a high tan ⁇ . As a result, it is presumed that heat generation during bending is large and deterioration proceeds greatly.
  • Examples 2-1 to 2-5 have better belt durability than Comparative Examples 2-1 to 2-4.
  • the present invention is useful in the technical field of recycled rubber, a method for producing the same, and a transmission belt using the same.

Abstract

A regenerated rubber which is derived from a sulfur-crosslinked rubber composition containing ethylene, propylene, and diene monomers and which has a gel content of 50-85 mass%.

Description

再生ゴム及びその製造方法、並びにそれを用いた伝動ベルトRecycled rubber, method for producing the same, and transmission belt using the same
　本発明は、再生ゴム及びその製造方法、並びにそれを用いた伝動ベルトに関する。 The present invention relates to recycled rubber, a method for producing the same, and a transmission belt using the same.
　再生ゴムは、使用済みのゴム製品の架橋ゴムに化学的処理或いは物理的処理を施すことにより、再び成形加工可能な状態にしたものである。再生ゴムの使用は、ゴム製品の材料コスト及び製造コストの削減に極めて有効である。 Recycled rubber is made into a state where it can be molded again by applying chemical treatment or physical treatment to the crosslinked rubber of used rubber products. The use of recycled rubber is extremely effective in reducing the material cost and manufacturing cost of rubber products.
　特許文献１には、架橋ゴムに、温度１８０～３５０℃及び剪断応力１０～１５０ｋｇ／ｃｍ２の条件の脱硫処理を施す再生ゴムの製造方法が開示されている。 Patent Document 1 discloses a method for producing a recycled rubber in which a crosslinked rubber is subjected to a desulfurization treatment under conditions of a temperature of 180 to 350 ° C. and a shear stress of 10 to 150 kg / cm 2 .
　特許文献２には、架橋ゴムに、そのゴム分子間の架橋等の切断が起こる再生温度以上の加熱温度で剪断応力を加える再生ゴムの製造方法が開示されている。 Patent Document 2 discloses a method for producing a reclaimed rubber in which a shearing stress is applied to a crosslinked rubber at a heating temperature equal to or higher than the regenerating temperature at which a break such as cross-linking between the rubber molecules occurs.
　特許文献３には、架橋ゴムの原料粉とジエン系ゴムとを混合し、それに、最大剪断速度３００／秒以上の剪断応力を加える再生ゴムの製造方法が開示されている。 Patent Document 3 discloses a method for producing a reclaimed rubber in which a raw material powder of a crosslinked rubber and a diene rubber are mixed and a shear stress of a maximum shear rate of 300 / sec or more is applied thereto.
　特許文献４には、架橋ゴムに、温度２２０～３５０℃及び剪断応力１０～１５０ｋｇ／ｃｍ２の条件の脱硫処理を施す再生ゴムの製造方法が開示されている。 Patent Document 4 discloses a method for producing a recycled rubber in which a crosslinked rubber is subjected to a desulfurization treatment under conditions of a temperature of 220 to 350 ° C. and a shear stress of 10 to 150 kg / cm 2 .
特開平９－２２７７２４号公報JP-A-9-227724 特開２００１－３０２３７号公報JP 2001-30237 A 特開２００３－１２８８４３号公報Japanese Patent Laid-Open No. 2003-128843 特開２００４－３５６９０号公報JP 2004-35690 A
　本発明の再生ゴムは、ゴム成分としてエチレンプロピレンジエンモノマーを含み、且つゲル分率が５０～８５質量％である。 The recycled rubber of the present invention contains ethylene propylene diene monomer as a rubber component and has a gel fraction of 50 to 85% by mass.
　本発明の再生ゴムの製造方法は、硫黄架橋されたエチレンプロピレンジエンモノマーを含む架橋ゴムを粉砕し、前記粉砕した架橋ゴムに剪断応力を加えて脱硫処理を施すゲル分率が５０～８５質量％である。 The method for producing a reclaimed rubber according to the present invention has a gel fraction of 50 to 85% by mass in which a crosslinked rubber containing sulfur-crosslinked ethylene propylene diene monomer is pulverized and subjected to desulfurization treatment by applying shear stress to the crushed crosslinked rubber. It is.
　本発明の伝動ベルトは、本発明の再生ゴムが用いられたゴム組成物によりベルト本体の少なくとも一部が構成されている。 In the transmission belt of the present invention, at least a part of the belt main body is made of a rubber composition using the recycled rubber of the present invention.
実施形態１に係るラップドＶベルトの一片の斜視図である。1 is a perspective view of a piece of a wrapped V belt according to Embodiment 1. FIG. 実施形態に係るラップドＶベルトの製造方法を示す第１の説明図である。It is the 1st explanatory view showing the manufacturing method of the wrapped V belt concerning an embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第２の説明図である。It is 2nd explanatory drawing which shows the manufacturing method of the wrapped V belt which concerns on embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第３の説明図である。It is 3rd explanatory drawing which shows the manufacturing method of the wrapped V belt which concerns on embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第４の説明図である。It is a 4th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第５の説明図である。It is a 5th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第６の説明図である。It is a 6th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment. 実施形態に係るラップドＶベルトの製造方法を示す第７の説明図である。It is a 7th explanatory view showing a manufacturing method of a wrapped V belt concerning an embodiment. 実施例で用いたベルト走行試験機のプーリレイアウト図である。It is a pulley layout figure of the belt run test machine used in the example. 実施例２-１の再生ゴムの切断面の観察写真である。It is an observation photograph of the cut surface of the recycled rubber of Example 2-1.
　以下、実施形態について図面を参照しながら説明する。 Hereinafter, embodiments will be described with reference to the drawings.
　（実施形態１）
　＜再生ゴム＞
　実施形態１に係る再生ゴムは、硫黄架橋されたエチレンプロピレンジエンモノマー（以下「ＥＰＤＭ」という。）を含むゴム組成物を由来とし、且つゲル分率が５０～８５質量％と高いものである。実施形態１に係る再生ゴムは、硫黄架橋されたＥＰＤＭを由来とし、その硫黄架橋に起因したゲル分率が５０～８５質量％と高いので、これを用いたゴム組成物では、ゴム弾性が高いと共にｔａｎδが低い。従って、実施形態１に係る再生ゴムを用いたゴム組成物により、特に繰り返し屈曲される伝動ベルトのベルト本体の少なくとも一部を構成することが好適である。 (Embodiment 1)
<Recycled rubber>
The recycled rubber according to Embodiment 1 is derived from a rubber composition containing sulfur-crosslinked ethylene propylene diene monomer (hereinafter referred to as “EPDM”), and has a high gel fraction of 50 to 85 mass%. The recycled rubber according to Embodiment 1 is derived from sulfur-crosslinked EPDM, and the gel fraction resulting from the sulfur crosslinking is as high as 50 to 85% by mass. Therefore, the rubber composition using the recycled rubber has high rubber elasticity. At the same time, tan δ is low. Therefore, it is preferable that at least a part of the belt main body of the transmission belt that is bent repeatedly is constituted by the rubber composition using the recycled rubber according to the first embodiment.
　ここで、実施形態１に係る再生ゴムのゲル分率は、再架橋し易く、且つ物性の劣化を抑えると共に優れた加工性を得ることができるという観点から、好ましくは５０質量％以上、より好ましくは６５質量％以上であり、また、好ましくは８５質量％以下、より好ましくは８０質量％以下である。 Here, the gel fraction of the reclaimed rubber according to Embodiment 1 is preferably 50% by mass or more, more preferably from the viewpoint of being easy to re-crosslink, suppressing deterioration of physical properties and obtaining excellent processability. Is 65% by mass or more, preferably 85% by mass or less, more preferably 80% by mass or less.
　ゲル分率はいわゆるトルエン膨潤法により求められる。具体的には、再生ゴムの試験片（例えば２０ｍｍ×１０ｍｍ×２ｍｍの短冊状）を切り出し、これを３０℃のトルエンに７２時間浸漬して膨潤させた後に乾燥させ、トルエン浸漬前の質量（Ｗ０）及びトルエン浸漬後の質量（Ｗ３）から、ゲル分率ｇｗ＝（Ｗ３／Ｗ０）×１００と算出される。なお、この方法は、例えば「ゴム試験法（社団法人　日本ゴム協会　編集発行）」等にも記載されている。 The gel fraction is determined by a so-called toluene swelling method. Specifically, a test piece of recycled rubber (for example, 20 mm × 10 mm × 2 mm strip) was cut out, immersed in toluene at 30 ° C. for 72 hours, swelled, dried, and mass (W 0 ) and the mass (W 3 ) after immersion in toluene, the gel fraction g w = (W 3 / W 0 ) × 100 is calculated. This method is also described in, for example, “Rubber Test Method (edited and published by Japan Rubber Association)”.
　実施形態１に係る再生ゴムは、ゴム成分とそれ以外のゴム配合剤とを含む。 The recycled rubber according to Embodiment 1 includes a rubber component and other rubber compounding agents.
　実施形態１に係る再生ゴムにおけるゴム成分の含有量は、好ましくは３０質量％以上、より好ましくは４０質量％以上であり、また、好ましくは７０質量％以下、より好ましくは６０質量％以下である。 The content of the rubber component in the recycled rubber according to Embodiment 1 is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less. .
　実施形態１に係る再生ゴムのゴム成分におけるＥＰＤＭの含有量は、好ましくは５０質量％以上、より好ましくは７０質量％以上である。再生ゴムのゴム成分におけるＥＰＤＭの含有量は１００質量％であることが最も好ましい、つまり、再生ゴムのゴム成分がＥＰＤＭのみであることが最も好ましい。 The content of EPDM in the rubber component of the recycled rubber according to Embodiment 1 is preferably 50% by mass or more, more preferably 70% by mass or more. The content of EPDM in the rubber component of the recycled rubber is most preferably 100% by mass, that is, the rubber component of the recycled rubber is most preferably only EPDM.
　なお、実施形態１に係る再生ゴムに含まれ得るＥＰＤＭ以外のゴム成分としては、例えば、エチレンプロピレンゴム（ＥＰＭ）などのＥＰＤＭ以外のエチレン－α－オレフィンエラストマーや天然ゴム（ＮＲ）等が挙げられる。 Examples of rubber components other than EPDM that can be included in the recycled rubber according to Embodiment 1 include ethylene-α-olefin elastomers other than EPDM such as ethylene propylene rubber (EPM), natural rubber (NR), and the like. .
　実施形態１に係る再生ゴムに含まれるゴム配合剤としては、後述の脱硫処理前から含まれていた、例えば、カーボンブラックなどの補強材、軟化剤、加工助剤、加硫促進助剤、架橋剤、加硫促進剤、老化防止剤等が挙げられる。 As a rubber compounding agent contained in the recycled rubber according to Embodiment 1, for example, a reinforcing material such as carbon black, a softening agent, a processing aid, a vulcanization acceleration aid, and a crosslinking agent, which have been contained before the desulfurization treatment described later. Agents, vulcanization accelerators, anti-aging agents and the like.
　実施形態１に係る再生ゴムは、バージンゴムがブレンドされてベースゴム材料とされ、或いは、そのままベースゴム材料とされ、そして、それに架橋剤を含む各種のゴム配合剤が配合され、例えば、伝動ベルト、コンベヤベルト、タイヤ、ホース等のゴム製品を構成するゴム組成物として用いられる。上記の通り、これらのうち特に伝動ベルトに好適である。 The recycled rubber according to the first embodiment is blended with virgin rubber to be a base rubber material, or is used as it is as a base rubber material, and various rubber compounding agents including a crosslinking agent are blended therein. For example, a transmission belt It is used as a rubber composition constituting rubber products such as conveyor belts, tires and hoses. As described above, among these, it is particularly suitable for a transmission belt.
　実施形態１に係る再生ゴムは、使用済みのゴム製品から架橋ゴム（架橋済みゴム組成物）を取り出し、その架橋ゴムを所定の方法により脱硫処理することにより得ることができる。具体的には、実施形態１に係る再生ゴムは、硫黄架橋されたＥＰＤＭを含む架橋ゴムを予め粉砕して粉状乃至粒状とし、その後、粉状乃至粒状にした架橋ゴムに所定の処理温度下で剪断応力を加えて脱硫処理することにより得られる。このとき、再生ゴムのゲル分率は、脱硫処理の際の処理温度、剪断応力、及び処理時間等の条件の組み合わせによって制御することができる。このように脱硫処理して得られる再生ゴムは、硫黄の架橋点の一部及びＥＰＤＭの主鎖が切断されることにより、架橋可能なＥＰＤＭと、残留した硫黄架橋によるゲル分の弾性ゴムのＥＰＤＭとを含み、その結果、これを用いたゴム組成物では、バージンゴムのみを用いた場合と比較して、ゴム弾性が高いと共にｔａｎδが低くなる。 The recycled rubber according to Embodiment 1 can be obtained by taking out a crosslinked rubber (crosslinked rubber composition) from a used rubber product and desulfurizing the crosslinked rubber by a predetermined method. Specifically, the recycled rubber according to Embodiment 1 is obtained by previously pulverizing a crosslinked rubber containing sulfur-crosslinked EPDM into a powdery or granular form, and then applying the powdered or granular crosslinked rubber to a predetermined processing temperature. It is obtained by applying a shearing stress at desulfurization treatment. At this time, the gel fraction of the recycled rubber can be controlled by a combination of conditions such as the processing temperature, shear stress, and processing time during the desulfurization process. The regenerated rubber obtained by the desulfurization treatment in this way has a crosslinkable EPDM by cutting a part of the sulfur crosslinking point and the main chain of the EPDM, and the EPDM of the elastic rubber for the gel due to the remaining sulfur crosslinking. As a result, in the rubber composition using this, the rubber elasticity is high and the tan δ is low as compared with the case where only the virgin rubber is used.
　ここで、使用済みのゴム製品としては、例えば、伝動ベルト、コンベヤベルト、タイヤ、ホース等が挙げられる。 Here, examples of the used rubber product include a transmission belt, a conveyor belt, a tire, and a hose.
　粉状乃至粒状の架橋ゴムの平均粒径は、好ましくは１０μｍ以上、より好ましくは１００μｍ以上であり、また、好ましくは５ｍｍ以下、より好ましくは３ｍｍ以下である。 The average particle diameter of the powdery or granular crosslinked rubber is preferably 10 μm or more, more preferably 100 μm or more, and preferably 5 mm or less, more preferably 3 mm or less.
　脱硫処理の処理温度は、１５０～２５０℃であり、脱硫と残留するゲル分とのバランスの観点から、好ましくは１８０℃以上であり、また、好ましくは２３０℃以下である。脱硫処理の際の剪断応力は、脱硫と残留するゲル分とのバランスの観点から、好ましくは０．９８１ＭＰａ以上、より好ましくは４ＭＰａ以上であり、また、好ましくは２０ＭＰａ以下、より好ましくは１５ＭＰａ以下である。 The treatment temperature of the desulfurization treatment is 150 to 250 ° C., and preferably 180 ° C. or more and preferably 230 ° C. or less from the viewpoint of the balance between the desulfurization and the remaining gel content. The shear stress during the desulfurization treatment is preferably 0.981 MPa or more, more preferably 4 MPa or more, and preferably 20 MPa or less, more preferably 15 MPa or less, from the viewpoint of the balance between the desulfurization and the residual gel content. is there.
　以上のような脱硫処理は、単軸又は二軸の押出成形機等の公知の加工設備を用いて行うことができる。 The desulfurization treatment as described above can be performed using known processing equipment such as a single-screw or twin-screw extruder.
　なお、実施形態１に係る再生ゴムは、最大粒径が２５０μｍ以下の熱可塑性樹脂の配合材料が分散して含まれていてもよい。最大粒径が２５０μｍ以下の熱可塑性樹脂の配合材料が分散して含まれた再生ゴムから得られるゴム組成物は、低ｔａｎδとなることから、繰り返し屈曲された際でも発熱が抑えられ、従って、伝動ベルト等の繰り返し屈曲を受けるゴム製品への適用に好適である。 Note that the recycled rubber according to Embodiment 1 may contain a dispersion of a thermoplastic resin compounding material having a maximum particle size of 250 μm or less. A rubber composition obtained from a recycled rubber containing a dispersion material of a thermoplastic resin having a maximum particle size of 250 μm or less has a low tan δ, so that heat generation is suppressed even when it is repeatedly bent. It is suitable for application to rubber products that are repeatedly bent such as a transmission belt.
　熱可塑性樹脂の配合材料としては、例えば、ポリアミド樹脂（ＰＡ）、ポリエチレンテレフタレート樹脂（ＰＥＴ）、ポリプロピレン樹脂（ＰＰ）等の配合材料が挙げられる。ポリアミド樹脂（ＰＡ）としては、例えば、ナイロン６、ナイロン６６等が挙げられる。熱可塑性樹脂の配合材料は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。熱可塑性樹脂の配合材料の形態としては、例えば、粉状、粒状、繊維状等が挙げられる。これらのうち繊維状のもの、特に、繊維径が１０～３０μｍ及び繊維長が１～５ｍｍの短繊維が好ましい。 Examples of the blending material of the thermoplastic resin include blending materials such as polyamide resin (PA), polyethylene terephthalate resin (PET), and polypropylene resin (PP). Examples of the polyamide resin (PA) include nylon 6, nylon 66, and the like. The compounding material of the thermoplastic resin may be composed of a single type or a plurality of types. Examples of the form of the blended material of the thermoplastic resin include powdery, granular, and fibrous forms. Of these, fibrous fibers, particularly short fibers having a fiber diameter of 10 to 30 μm and a fiber length of 1 to 5 mm are preferred.
　熱可塑性樹脂の配合材料の最大粒径は、得られる再生ゴムにおける熱可塑性樹脂の配合材料の界面でのクラックの発生を抑制する観点から、好ましくは２３０μｍ以下、より好ましくは２０５μｍ以下、更に好ましくは１５５μｍ以下、より更に好ましくは１５０μｍ以下であり、また、好ましくは５μｍ以上、より好ましくは２０μｍ以上、更に好ましくは５０μｍ以上、より更に好ましくは１００μｍ以上である。この再生ゴム中の熱可塑性樹脂の配合材料の最大粒径は、脱硫処理における剪断応力等によって制御することができる。また、熱可塑性樹脂の配合材料の最大粒径は、得られた再生ゴムの表面観察により測定することができる。 The maximum particle size of the thermoplastic resin compounding material is preferably 230 μm or less, more preferably 205 μm or less, and even more preferably from the viewpoint of suppressing the occurrence of cracks at the interface of the thermoplastic resin compounding material in the obtained recycled rubber. It is 155 μm or less, more preferably 150 μm or less, preferably 5 μm or more, more preferably 20 μm or more, still more preferably 50 μm or more, and even more preferably 100 μm or more. The maximum particle size of the thermoplastic resin compounding material in the recycled rubber can be controlled by the shear stress or the like in the desulfurization process. The maximum particle size of the thermoplastic resin compounding material can be measured by observing the surface of the obtained recycled rubber.
　再生ゴムにおける熱可塑性樹脂の配合材料の含有量は、好ましくは２質量％以上、より好ましくは８質量％以上であり、また、好ましくは３０質量％以下、より好ましくは２０質量％以下である。また、かかる最大粒径が２５０μｍ以下の熱可塑性樹脂を含む再生ゴムを製造する際には、脱硫処理における処理温度を、熱可塑性樹脂の配合材料の融点よりも２０℃以上低い温度に設定することが好ましい。 The content of the compounding material of the thermoplastic resin in the recycled rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less. Further, when producing a recycled rubber containing a thermoplastic resin having a maximum particle size of 250 μm or less, the treatment temperature in the desulfurization treatment is set to a temperature that is 20 ° C. or more lower than the melting point of the thermoplastic resin compounding material. Is preferred.
　＜ラップドＶベルトＢ＞
　図１は、実施形態１に係るラップドＶベルトＢ（伝動ベルト）を示す。この実施形態１に係るラップドＶベルトＢは、例えば、農業機械や産業機械に使用されるものである。実施形態１に係るラップドＶベルトＢの寸法は、特に限定されるものではないが、例えば、ベルト周長７００～５０００ｍｍ、ベルト幅１６～１７ｍｍ、及びベルト厚さ８～１０ｍｍである。 <Wrapped V belt B>
FIG. 1 shows a wrapped V-belt B (power transmission belt) according to the first embodiment. The wrapped V belt B according to the first embodiment is used for, for example, an agricultural machine or an industrial machine. The dimensions of the wrapped V-belt B according to the first embodiment are not particularly limited, and are, for example, a belt circumferential length of 700 to 5000 mm, a belt width of 16 to 17 mm, and a belt thickness of 8 to 10 mm.
　実施形態１に係るラップドＶベルトＢは、ベルト内周側（プーリ接触側）の圧縮ゴム層１１と、中間の接着ゴム層１２と、ベルト外周側の伸張ゴム層１３との三重の層に構成された横断面形状が台形のベルト本体１０を備える。接着ゴム層１２には、ベルト幅方向にピッチを有する螺旋を形成するように配された心線１４が埋設されている。ベルト本体１０は、全体が補強布１５によって覆われている。 The wrapped V-belt B according to the first embodiment is configured in a triple layer of a compression rubber layer 11 on the belt inner peripheral side (pulley contact side), an intermediate adhesive rubber layer 12 and a stretched rubber layer 13 on the belt outer peripheral side. The belt body 10 having a trapezoidal cross-sectional shape is provided. A core wire 14 is embedded in the adhesive rubber layer 12 so as to form a spiral having a pitch in the belt width direction. The belt body 10 is entirely covered with a reinforcing cloth 15.
　圧縮ゴム層１１、接着ゴム層１２、及び伸張ゴム層１３は、いずれも架橋したゴム組成物で構成されている。そして、圧縮ゴム層１１、接着ゴム層１２、及び伸張ゴム層１３のうち少なくとも１つは、実施形態１に係る再生ゴムが用いられて架橋したゴム組成物で構成されている。圧縮ゴム層１１、接着ゴム層１２、及び伸張ゴム層１３を構成するゴム組成物は、いずれも実施形態１に係る再生ゴムが用いられていることが好ましいが、その場合、それらが同一のゴム組成物であってもよい。 The compressed rubber layer 11, the adhesive rubber layer 12, and the stretch rubber layer 13 are all composed of a crosslinked rubber composition. At least one of the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is composed of a rubber composition that is cross-linked using the reclaimed rubber according to the first embodiment. The rubber composition constituting the compressed rubber layer 11, the adhesive rubber layer 12, and the stretched rubber layer 13 is preferably made of the reclaimed rubber according to the first embodiment, and in that case, the same rubber is used. It may be a composition.
　ここで、この実施形態１に係る再生ゴムが用いられたゴム組成物は、実施形態１に係る再生ゴムをベースゴム材料としていてもよく、また、それにゴム成分としてバージンゴムがブレンドされてベースゴム材料としていてもよい。この場合のバージンゴムは、エチレン－α－オレフィンエラストマーが好ましく、そのうちでもＥＰＤＭがより好ましい。ゴム組成物のゴム成分におけるバージンゴムの含有量は、好ましくは２０質量％以上であり、また、好ましくは８０質量％以下、より好ましくは６０質量％以下である。 Here, the rubber composition using the reclaimed rubber according to the first embodiment may use the reclaimed rubber according to the first embodiment as a base rubber material, and virgin rubber is blended as a rubber component to the base rubber. It may be used as a material. In this case, the virgin rubber is preferably an ethylene-α-olefin elastomer, and more preferably EPDM. The content of virgin rubber in the rubber component of the rubber composition is preferably 20% by mass or more, preferably 80% by mass or less, more preferably 60% by mass or less.
　この実施形態１に係る再生ゴムが用いられたゴム組成物には、実施形態１に係る再生ゴムに含まれるゴム配合剤に加えて、各種のゴム配合剤が配合されている。かかるゴム配合剤としては、例えば、カーボンブラックなどの補強材、軟化剤、加工助剤、加硫促進助剤、架橋剤、加硫促進剤、老化防止剤等が挙げられる。 In the rubber composition using the recycled rubber according to the first embodiment, various rubber compounding agents are blended in addition to the rubber compounding agent contained in the recycled rubber according to the first embodiment. Examples of such rubber compounding agents include reinforcing materials such as carbon black, softeners, processing aids, vulcanization acceleration aids, crosslinking agents, vulcanization accelerators, and antiaging agents.
　補強材は、実施形態１に係る再生ゴムが補強材を含む場合には、配合されなくてもよい。一方、補強材は、実施形態１に係る再生ゴムを含むゴム組成物にバージンゴムが含まれている場合には、配合されることが好ましい。 The reinforcing material may not be blended when the recycled rubber according to Embodiment 1 includes the reinforcing material. On the other hand, the reinforcing material is preferably blended when the rubber composition containing the recycled rubber according to Embodiment 1 contains virgin rubber.
　補強材としては、カーボンブラックでは、例えば、チャネルブラック；ＳＡＦ、ＩＳＡＦ、Ｎ－３３９、ＨＡＦ、Ｎ－３５１、ＭＡＦ、ＦＥＦ、ＳＲＦ、ＧＰＦ、ＥＣＦ、Ｎ－２３４などのファーネスブラック；ＦＴ、ＭＴなどのサーマルブラック；アセチレンブラック等が挙げられる。補強剤としてはシリカも挙げられる。補強剤は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。補強材の含有量は、耐摩耗性と耐屈曲性とのバランスの観点から、ゴム組成物のゴム成分１００質量部に対して３０～８０質量部であることが好ましい。 As a reinforcing material, for example, carbon black, channel black; furnace black such as SAF, ISAF, N-339, HAF, N-351, MAF, FEF, SRF, GPF, ECF, N-234; FT, MT, etc. Thermal black; acetylene black and the like. Silica is also mentioned as a reinforcing agent. The reinforcing agent may be composed of a single species or a plurality of species. The content of the reinforcing material is preferably 30 to 80 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition, from the viewpoint of a balance between wear resistance and bending resistance.
　軟化剤としては、例えば、石油系軟化剤、パラフィンワックスなどの鉱物油系軟化剤、ひまし油、綿実油、あまに油、なたね油、大豆油、パーム油、やし油、落下生油、木ろう、ロジン、パインオイルなどの植物油系軟化剤等が挙げられる。軟化剤は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。軟化剤の含有量は、ゴム組成物のゴム成分１００質量部に対して例えば２～３０質量部である。 Examples of the softener include petroleum softeners, mineral oil softeners such as paraffin wax, castor oil, cottonseed oil, sesame oil, rapeseed oil, soybean oil, palm oil, palm oil, fallen raw oil, waxy wax, rosin And vegetable oil-based softeners such as pine oil. The softener may be composed of a single species or a plurality of species. The content of the softening agent is, for example, 2 to 30 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
　加工助剤としては、例えば、ステアリン酸、ポリエチレンワックス、脂肪酸の金属塩等が挙げられる。加工助剤は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。加工助剤の含有量は、ゴム組成物のゴム成分１００質量部に対して例えば０．１～３質量部である。 Examples of processing aids include stearic acid, polyethylene wax, and fatty acid metal salts. The processing aid may be composed of a single species or a plurality of species. The content of the processing aid is, for example, 0.1 to 3 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
　加硫促進助剤としては、例えば、酸化マグネシウムや酸化亜鉛（亜鉛華）などの金属酸化物、金属炭酸塩、脂肪酸及びその誘導体等が挙げられる。加硫促進助剤は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。加硫促進助剤の含有量は、ゴム組成物のゴム成分１００質量部に対して例えば０．５～８質量部である。 Examples of the vulcanization acceleration aid include metal oxides such as magnesium oxide and zinc oxide (zinc white), metal carbonates, fatty acids and derivatives thereof. The vulcanization acceleration aid may be composed of a single species or a plurality of species. The content of the vulcanization acceleration aid is, for example, 0.5 to 8 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
　架橋剤としては、硫黄及び有機過酸化物が挙げられる。架橋剤として、硫黄が配合されていてもよく、また、有機過酸化物が配合されていてもよく、更には、それらの両方が併用されていてもよい。架橋剤の配合量は、硫黄の場合、ゴム組成物のゴム成分１００質量部に対して例えば０．５～４．０質量部であり、有機過酸化物の場合、ゴム組成物のゴム成分１００質量部に対して例えば０．５～８．０質量部である。 Examples of the crosslinking agent include sulfur and organic peroxides. As a crosslinking agent, sulfur may be blended, an organic peroxide may be blended, or both of them may be used in combination. The compounding amount of the crosslinking agent is, for example, 0.5 to 4.0 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition in the case of sulfur, and the rubber component 100 of the rubber composition in the case of organic peroxide. For example, 0.5 to 8.0 parts by mass with respect to parts by mass.
　有機過酸化物としては、例えば、ジクミルパーオキサイドなどのジアルキルパーオキサイド類、ｔ－ブチルパーオキシアセテートなどのパーオキシエステル類、ジシクロヘキサノンパーオキサイドなどのケトンパーオキサイド類等が挙げられる。有機過酸化物は、単一種が配合されていても、また、複数種が配合されていても、どちらでもよい。 Examples of the organic peroxide include dialkyl peroxides such as dicumyl peroxide, peroxyesters such as t-butyl peroxyacetate, and ketone peroxides such as dicyclohexanone peroxide. The organic peroxide may be a single species or a plurality of species.
　ゴム組成物は、架橋剤が硫黄の場合、残留した硫黄架橋によるゲル分と、追加の硫黄架橋に由来する硫黄結合とを含むこととなり、架橋剤が有機過酸化物の場合、残留した硫黄架橋によるゲル分と、有機過酸化物架橋に由来するＣ－Ｃ結合とを含むこととなる。従って、実施形態１に係る再生ゴムを用いることにより、ＥＰＤＭのバージンゴムのみを用いたゴム組成物に比べると、架橋点が多いゴム組成物を得ることができる。 When the crosslinking agent is sulfur, the rubber composition includes a gel component due to residual sulfur crosslinking and a sulfur bond derived from additional sulfur crosslinking. When the crosslinking agent is an organic peroxide, residual rubber crosslinking And a C—C bond derived from organic peroxide crosslinking. Therefore, by using the recycled rubber according to Embodiment 1, a rubber composition having more crosslinking points can be obtained as compared with a rubber composition using only EPDM virgin rubber.
　加硫促進剤としては、例えば、チアゾール系（例えばＭＢＴ、ＭＢＴＳなど）、チウラム系（例えばＴＴ、ＴＲＡなど）、スルフェンアミド系（例えばＣＺなど）、ジチオカルバミン酸塩系（例えばＢＺ－Ｐなど）のもの等が挙げられる。加硫促進剤は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。特に架橋剤として硫黄が用いられる場合には、加硫促進剤が配合されることが好ましく、その場合、チアゾール系加硫促進剤及びチウラム系加硫促進剤を併用することが好ましい。加硫促進剤の含有量は、ゴム組成物のゴム成分１００質量部に対して例えば２～１０質量部である。 Examples of the vulcanization accelerator include thiazole type (eg MBT, MBTS etc.), thiuram type (eg TT, TRA etc.), sulfenamide type (eg CZ etc.), dithiocarbamate type (eg BZ-P etc.) And the like. The vulcanization accelerator may be composed of a single species or a plurality of species. In particular, when sulfur is used as the crosslinking agent, a vulcanization accelerator is preferably added. In that case, it is preferable to use a thiazole vulcanization accelerator and a thiuram vulcanization accelerator in combination. The content of the vulcanization accelerator is, for example, 2 to 10 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
　老化防止剤としては、アミン系、キノリン系、ヒドロキノン誘導体、フェノール系、亜リン酸エステル系のものが挙げられる。老化防止剤は、単一種で構成されていてもよく、また、複数種で構成されていてもよい。老化防止剤の含有量は、ゴム組成物のゴム成分１００質量部に対して例えば０～８質量部である。 Antiaging agents include amine-based, quinoline-based, hydroquinone derivatives, phenol-based and phosphite-based agents. The anti-aging agent may be composed of a single species or a plurality of species. The content of the anti-aging agent is, for example, 0 to 8 parts by mass with respect to 100 parts by mass of the rubber component of the rubber composition.
　なお、ゴム配合剤として、その他に、スメクタイト族、バーミュライト族、カオリン族等の層状珪酸塩が配合されていてもよい。 In addition, as a rubber compounding agent, layered silicates such as smectite group, vermulite group, kaolin group and the like may be blended.
　実施形態１に係る再生ゴムが用いられたゴム組成物の列理方向における１００℃での損失係数ｔａｎδは、好ましくは０．０４以上、より好ましくは０．０６以上であり、また、好ましくは０．１５以下、より好ましくは０．１２以下である。損失係数ｔａｎδは、ＪＩＳＫ６３９４に基づいて求められる。 The loss coefficient tan δ at 100 ° C. in the line direction of the rubber composition using the recycled rubber according to Embodiment 1 is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0. .15 or less, more preferably 0.12 or less. The loss coefficient tan δ is obtained based on JISK6394.
　心線１４は、ポリエステル繊維（ＰＥＴ）、ポリエチレンナフタレート繊維（ＰＥＮ）、アラミド繊維、ビニロン繊維等の撚り糸で構成されている。心線１４は、ベルト本体１０に対する接着性を付与するために、成形加工前にＲＦＬ水溶液に浸漬した後に加熱する接着処理及び／又はゴム糊に浸漬した後に乾燥させる接着処理が施されている。 The core wire 14 is composed of twisted yarns such as polyester fiber (PET), polyethylene naphthalate fiber (PEN), aramid fiber, vinylon fiber and the like. In order to give the core wire 14 adhesion to the belt main body 10, an adhesive treatment for heating after being immersed in an RFL aqueous solution before molding and / or an adhesive treatment for drying after being immersed in rubber paste is performed.
　補強布１５は、例えば、綿、ポリアミド繊維、ポリエステル繊維、アラミド繊維等の糸で形成された織布、編物、不織布等によって構成されている。補強布１５は、ベルト本体１０に対する接着性を付与するために、成形加工前にＲＦＬ水溶液に浸漬して加熱する接着処理、及び／又は、ベルト本体１０側となる表面にゴム糊をコーティングして乾燥させる接着処理が施されている。 The reinforcing cloth 15 is made of, for example, a woven fabric, a knitted fabric, a non-woven fabric, or the like formed of yarns such as cotton, polyamide fiber, polyester fiber, and aramid fiber. In order to provide the adhesiveness to the belt main body 10, the reinforcing cloth 15 is coated with rubber paste on the surface on the side of the belt main body 10 and / or an adhesive treatment in which it is immersed in an RFL aqueous solution and heated before molding. Adhesive treatment for drying is applied.
　次に、実施形態１に係るラップドＶベルトＢの製造方法を説明する。 Next, a manufacturing method of the wrapped V belt B according to the first embodiment will be described.
　まず、圧縮ゴム層用のゴムシート１１’、接着ゴム層用のゴムシート１２’、及び伸張ゴム層用のゴムシート１３’、並びに心線用の撚り糸１４’及び補強布用の布１５’を準備する。このとき、圧縮ゴム層用のゴムシート１１’、接着ゴム層用のゴムシート１２’、及び伸張ゴム層用のゴムシート１３’のうち実施形態１に係る再生ゴムを含めるものは、実施形態１に係る再生ゴムとゴム配合剤とを混練した未架橋ゴム組成物を、カレンダロール等を用いてシート状に加工することにより得る。また心線用の撚り糸１４’及び補強布用の布１５’には接着処理を施す。 First, a rubber sheet 11 ′ for the compression rubber layer, a rubber sheet 12 ′ for the adhesive rubber layer, a rubber sheet 13 ′ for the stretch rubber layer, a twisted yarn 14 ′ for the core wire, and a cloth 15 ′ for the reinforcing cloth prepare. At this time, among the rubber sheet 11 ′ for the compression rubber layer, the rubber sheet 12 ′ for the adhesive rubber layer, and the rubber sheet 13 ′ for the stretch rubber layer, those including the recycled rubber according to the first embodiment are the first embodiment. An uncrosslinked rubber composition obtained by kneading the recycled rubber and the rubber compounding agent is obtained by processing into a sheet shape using a calender roll or the like. Further, the twisted yarn 14 ′ for the core wire and the fabric 15 ′ for the reinforcing fabric are subjected to adhesion treatment.
　次いで、図２Ａに示すように、マントル２１に、圧縮ゴム層用のゴムシート１１’を複数回巻き付け、その上に、接着ゴム層用のゴムシート１２’を巻き付ける。その上に、図２Ｂに示すように、撚り糸１４’を螺旋状に巻き付ける。更にその上に、図２Ｃに示すように、接着ゴム層用のゴムシート１２’及び伸張ゴム層用のゴムシート１３’を順に巻き付けて円筒状の積層構造体１０’を作製する。 Next, as shown in FIG. 2A, the rubber sheet 11 'for the compression rubber layer is wound around the mantle 21 a plurality of times, and the rubber sheet 12' for the adhesive rubber layer is wound thereon. Further, as shown in FIG. 2B, the twisted yarn 14 'is wound in a spiral shape. Further thereon, as shown in FIG. 2C, a rubber sheet 12 'for the adhesive rubber layer and a rubber sheet 13' for the stretch rubber layer are wound in order to produce a cylindrical laminated structure 10 '.
　次いで、図２Ｄに示すように、円筒状の積層構造体１０’をマントル２１上で所定幅に輪切りにした後、それらをマントル２１から取り外す。 Next, as shown in FIG. 2D, the cylindrical laminated structure 10 ′ is cut into a predetermined width on the mantle 21 and then removed from the mantle 21.
　次いで、環状の積層構造体１０’を、圧縮ゴム層用のゴムシート１１’側を外側にして一対のプーリ間に巻き掛けて回転させながら、図２Ｅに示すように、圧縮ゴム層用のゴムシート１１’の積層部分の両側をＶ型に斜めに切除して体積を調整する。 Next, as shown in FIG. 2E, the annular laminated structure 10 'is wound around a pair of pulleys with the rubber sheet 11' side for the compressed rubber layer facing outward and rotated. The volume is adjusted by obliquely cutting both sides of the laminated portion of the sheet 11 ′ into a V shape.
　続いて、図２Ｆに示すように、環状の積層構造体１０’の外周を布１５’で被覆する。 Subsequently, as shown in FIG. 2F, the outer periphery of the annular laminated structure 10 'is covered with a cloth 15'.
　そして、図２Ｇに示すように、ラッピングした環状の積層構造体１０’を円筒金型２２の溝２３に嵌め入れ、それを加硫缶に入れて加熱及び加圧する。このとき、環状の積層構造体１０’のゴム成分が架橋してベルト本体１０を形成し、且つ撚り糸１４’がベルト本体１０に接着一体化して心線１４となると共に、布１５’がベルト本体１０に接着一体化して補強布１５となって実施形態１に係るラップドＶベルトＢが製造される。 Then, as shown in FIG. 2G, the lapped annular laminated structure 10 'is fitted into the groove 23 of the cylindrical mold 22, and it is placed in a vulcanizing can and heated and pressurized. At this time, the rubber component of the annular laminated structure 10 ′ is cross-linked to form the belt main body 10, and the twisted yarn 14 ′ is bonded and integrated to the belt main body 10 to form the core wire 14, and the cloth 15 ′ is the belt main body. The wrapped V-belt B according to the first embodiment is manufactured by being bonded and integrated with 10 to form the reinforcing cloth 15.
　（実施形態２）
　実施形態２に係る再生ゴムの製造方法では、使用済みのゴム製品から架橋ゴムを取り出し、熱可塑性樹脂の配合材料の存在下で、その架橋ゴムに剪断応力を加えて脱硫処理する。 (Embodiment 2)
In the method for producing recycled rubber according to the second embodiment, the crosslinked rubber is taken out from the used rubber product, and in the presence of the thermoplastic resin compounding material, the crosslinked rubber is subjected to desulfurization treatment by applying shear stress.
　ここで、使用済みのゴム製品としては、例えば、伝動ベルト、コンベヤベルト、タイヤ、ホース等が挙げられる。 Here, examples of the used rubber product include a transmission belt, a conveyor belt, a tire, and a hose.
　架橋ゴムに含まれるゴム成分としては、例えば、天然ゴム（ＮＲ）、ＥＰＤＭやＥＰＭのエチレン－α－オレフィンエラストマー、クロロプレンゴム（ＣＲ）、水素化ニトリルゴム（Ｈ－ＮＢＲ）、イソプレンゴム（ＩＲ）、スチレンブタジエンゴム（ＳＢＲ）、ブタジエンゴム（ＢＲ）、アクリロニトリルブタジエンゴム（ＮＢＲ）、ブチルゴム（ＩＩＲ）等が挙げられる。架橋ゴムに含まれるゴム成分は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。架橋ゴムにおけるゴム成分の含有量は、好ましくは３０質量％以上、より好ましくは４０質量％以上であり、また、好ましくは７０質量％以下、より好ましくは６０質量％以下である。 Examples of rubber components contained in the crosslinked rubber include natural rubber (NR), EPDM and EPM ethylene-α-olefin elastomers, chloroprene rubber (CR), hydrogenated nitrile rubber (H-NBR), and isoprene rubber (IR). Styrene butadiene rubber (SBR), butadiene rubber (BR), acrylonitrile butadiene rubber (NBR), butyl rubber (IIR) and the like. The rubber component contained in the crosslinked rubber may be composed of a single species or a plurality of species. The content of the rubber component in the crosslinked rubber is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less.
　架橋ゴムには、その他に、カーボンブラック、充填剤、老化防止剤、可塑剤等が配合されていてもよい。 In addition to the crosslinked rubber, carbon black, a filler, an anti-aging agent, a plasticizer, and the like may be blended.
　架橋ゴムは、ゴム成分が架橋されているが、硫黄により架橋されていても、また、有機過酸化物により架橋されていても、どちらでもよい。 In the crosslinked rubber, the rubber component is crosslinked, but it may be crosslinked by sulfur or by an organic peroxide.
　脱硫処理前の架橋ゴムは、効率的に脱硫処理を行う観点から、粉砕されて粉状乃至粒状であることが好ましい。粉状乃至粒状の架橋ゴムの平均粒径は、好ましくは１０μｍ以上、より好ましくは１００μｍ以上、更に好ましくは２００μｍ以上であり、また、好ましくは５ｍｍ以下、より好ましくは３ｍｍ以下である。 The crosslinked rubber before the desulfurization treatment is preferably pulverized and powdery or granular from the viewpoint of efficiently performing the desulfurization treatment. The average particle size of the powdery or granular crosslinked rubber is preferably 10 μm or more, more preferably 100 μm or more, still more preferably 200 μm or more, and preferably 5 mm or less, more preferably 3 mm or less.
　熱可塑性樹脂の配合材料としては、例えば、ポリアミド樹脂（ＰＡ）、ポリエチレンテレフタレート樹脂（ＰＥＴ）、ポリプロピレン樹脂（ＰＰ）等の配合材料が挙げられる。ポリアミド樹脂（ＰＡ）としては、例えば、ナイロン６、ナイロン６６等が挙げられる。熱可塑性樹脂の配合材料は、単一種で構成されていても、また、複数種で構成されていても、どちらでもよい。熱可塑性樹脂の配合材料の形態としては、例えば、粉状、粒状、繊維状等が挙げられる。これらのうち繊維状のもの、特に、繊維径が１０～３０μｍ及び繊維長が１～５ｍｍの短繊維が好ましい。 Examples of the blending material of the thermoplastic resin include blending materials such as polyamide resin (PA), polyethylene terephthalate resin (PET), and polypropylene resin (PP). Examples of the polyamide resin (PA) include nylon 6, nylon 66, and the like. The compounding material of the thermoplastic resin may be composed of a single type or a plurality of types. Examples of the form of the blended material of the thermoplastic resin include powdery, granular, and fibrous forms. Of these, fibrous fibers, particularly short fibers having a fiber diameter of 10 to 30 μm and a fiber length of 1 to 5 mm are preferred.
　熱可塑性樹脂の配合材料は、架橋ゴムに含まれている、つまり、使用済みのゴム製品から取り出した架橋ゴムに予め分散して配合され、それによって架橋ゴムに剪断が加えられる場に存在していることが好ましい。この場合、架橋ゴムにおける熱可塑性樹脂の配合材料の含有量は、好ましくは２質量％以上、より好ましくは８質量％以上であり、また、好ましくは２０質量％以下、より好ましくは１５質量％以下である。なお、熱可塑性樹脂の配合材料は、架橋ゴムには含まれておらず、脱硫処理の際に架橋ゴムと混合され、それによって架橋ゴムに剪断が加えられる場に存在していてもよい。 The compounding material of the thermoplastic resin is contained in the crosslinked rubber, that is, present in a place where the crosslinked rubber is pre-dispersed and compounded in the crosslinked rubber taken out from the used rubber product, whereby shearing is applied to the crosslinked rubber. Preferably it is. In this case, the content of the thermoplastic resin compounding material in the crosslinked rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass or less. It is. The compounding material of the thermoplastic resin is not contained in the crosslinked rubber, and may be present in a place where the crosslinked rubber is mixed with the crosslinked rubber during the desulfurization treatment and thereby shear is applied to the crosslinked rubber.
　実施形態２に係る再生ゴムの製造方法における脱硫処理は、架橋ゴムに剪断応力を加えて架橋部分の切断や解重合をさせる物理的処理である。具体的には、脱硫処理方法としては、例えば、一軸或いは二軸のスクリューを有する剪断流動場反応槽を用いて架橋ゴムを連続的に脱硫処理する方法が挙げられる。 The desulfurization treatment in the method for producing recycled rubber according to Embodiment 2 is a physical treatment in which shearing stress is applied to the crosslinked rubber to cut or depolymerize the crosslinked portion. Specifically, examples of the desulfurization treatment method include a method of continuously desulfurizing the crosslinked rubber using a shear flow field reaction tank having a uniaxial or biaxial screw.
　そして、実施形態２に係る再生ゴムの製造方法では、脱硫処理における処理温度を、熱可塑性樹脂の配合材料の融点よりも２０℃以上低い温度に設定する。ここで、脱硫処理における処理温度とは、脱硫処理時の被処理物の温度であり、例えば、一軸或いは二軸のスクリューを有する剪断流動場反応槽を用いた場合では、剪断流動場反応槽の槽内設定温度である。 And in the manufacturing method of the recycled rubber which concerns on Embodiment 2, the process temperature in a desulfurization process is set to the temperature 20 degreeC or more lower than melting | fusing point of the compounding material of a thermoplastic resin. Here, the treatment temperature in the desulfurization treatment is the temperature of the object to be treated at the time of the desulfurization treatment. For example, in the case of using a shear flow field reaction tank having a uniaxial or biaxial screw, It is the set temperature in the tank.
　ここで、熱可塑性樹脂の配合材料の融点は、ポリアミド樹脂（ＰＡ）では、例えば、ナイロン６の場合で２２５～２３５℃、ナイロン６６の場合で２６０～２７０℃であり、ポリエチレンテレフタレート樹脂（ＰＥＴ）の場合で２４５～２６５℃、ポリプロピレン樹脂（ＰＰ）の場合で１３５～１８０℃である。熱可塑性樹脂の配合材料の融点は、示差走査熱量計（DSC：Differential Scanning Calorimeter）により測定される。 Here, the melting point of the blended material of the thermoplastic resin is, for example, 225 to 235 ° C. in the case of nylon 6 and 260 to 270 ° C. in the case of nylon 66, and is a polyethylene terephthalate resin (PET). In the case of 245 to 265 ° C., in the case of polypropylene resin (PP), it is 135 to 180 ° C. Melting | fusing point of the compounding material of a thermoplastic resin is measured with a differential scanning calorimeter (DSC: Differential scanning Calorimeter).
　具体的には、脱硫処理における処理温度は、例えば、融点が２２５℃のナイロン６の配合材料の場合には２０５℃以下に設定し、融点が２６０℃のナイロン６６の場合には２４０℃以下に設定する。脱硫処理における処理温度は、得られる再生ゴムにおける物性低下を抑制する観点から、架橋ゴムに配合された熱可塑性樹脂の配合材料の融点よりも３０℃以上低い温度に設定することが好ましく、５０℃以上低い温度に設定することがより好ましく、６０℃以上低い温度に設定することが更に好ましく、また、適性に脱硫処理を行う観点から、１８０℃以上に設定することが好ましく、２００℃以上に設定することがより好ましい。なお、熱可塑性樹脂の配合材料が複数種ある場合には、それらの融点のうち最も低い融点よりも２０℃以上低い温度に設定する。 Specifically, the treatment temperature in the desulfurization treatment is, for example, set to 205 ° C. or less in the case of a blended material of nylon 6 having a melting point of 225 ° C., and to 240 ° C. or less in the case of nylon 66 having a melting point of 260 ° C. Set. The treatment temperature in the desulfurization treatment is preferably set to a temperature that is 30 ° C. or more lower than the melting point of the blended material of the thermoplastic resin blended with the crosslinked rubber, from the viewpoint of suppressing deterioration of physical properties in the obtained recycled rubber, 50 ° C. More preferably, it is set to a low temperature, more preferably set to a temperature lower than 60 ° C., and from the viewpoint of performing desulfurization appropriately, it is preferably set to 180 ° C. or higher, and set to 200 ° C. or higher. More preferably. In addition, when there are a plurality of blended materials of thermoplastic resins, the temperature is set to 20 ° C. or lower than the lowest melting point among these melting points.
　また、脱硫処理における剪断応力は、適性に脱硫処理を行う観点から、１ＭＰａ以上に設定することが好ましく、４ＭＰａ以上に設定することがより好ましく、また、熱可塑性樹脂の配合材料による効果が希薄化するのを規制する観点から、２０ＭＰａ以下に設定することが好ましく、１５ＭＰａ以下に設定することがより好ましい。 Further, the shear stress in the desulfurization treatment is preferably set to 1 MPa or more, more preferably set to 4 MPa or more from the viewpoint of appropriately performing the desulfurization treatment, and the effect of the blended material of the thermoplastic resin is diluted. From the viewpoint of regulating the operation, it is preferably set to 20 MPa or less, and more preferably set to 15 MPa or less.
　熱可塑性樹脂の配合材料が架橋ゴムに含まれている場合、製造する再生ゴムの物性調整の観点からは、脱硫処理において、熱可塑性樹脂の配合材料を含む架橋ゴムの外部に別の熱可塑性樹脂の配合材料を存在させる、つまり、熱可塑性樹脂の配合材料を含む架橋ゴムと別の熱可塑性樹脂の配合材料とを混合することが好ましい。別の熱可塑性樹脂の配合材料としては、上記で列挙したポリアミド樹脂（ＰＡ）等が挙げられ、その形態としては、例えば、粉状、粒状、繊維状等が挙げられる。別の熱可塑性樹脂の配合材料は、架橋ゴムに含まれた熱可塑性樹脂の配合材料と同一であっても、また、異なっていても、どちらでもよい。 When the blended material of the thermoplastic resin is contained in the crosslinked rubber, from the viewpoint of adjusting the physical properties of the recycled rubber to be produced, in the desulfurization treatment, another thermoplastic resin is provided outside the crosslinked rubber containing the blended material of the thermoplastic resin. In other words, it is preferable to mix a crosslinked rubber containing a thermoplastic resin compounding material with another thermoplastic resin compounding material. Another thermoplastic resin compounding material includes the above-mentioned polyamide resins (PA) and the like, and examples of the form include powdery, granular, fibrous and the like. The other thermoplastic resin compounding material may be the same as or different from the thermoplastic resin compounding material contained in the crosslinked rubber.
　実施形態２に係る再生ゴムの製造方法では、脱硫処理における剪断により熱可塑性樹脂の配合材料が切断されて小粒径化して分散し、脱硫処理後に得られる再生ゴムにおいて、架橋ゴムと同一のゴム成分中に、最大粒径が２５０μｍ以下の熱可塑性樹脂の配合材料が分散して含まれる。最大粒径が２５０μｍを越える熱可塑性樹脂の配合材料はもはや異物となり、クラック発生の起点になる虞がある。熱可塑性樹脂の配合材料の最大粒径は、得られる再生ゴムにおける熱可塑性樹脂の配合材料の界面でのクラックの発生を抑制する観点から、好ましくは２３０μｍ以下、より好ましくは２０５μｍ以下、更に好ましくは１５５μｍ以下、より更に好ましくは１５０μｍ以下であり、また、好ましくは５μｍ以上、より好ましくは２０μｍ以上、更に好ましくは５０μｍ以上、より更に好ましくは１００μｍ以上である。この再生ゴム中の熱可塑性樹脂の配合材料の最大粒径は、脱硫処理における剪断応力等によって制御することができる。また、熱可塑性樹脂の配合材料の最大粒径は、得られた再生ゴムの表面観察により測定することができる。 In the method for producing a reclaimed rubber according to the second embodiment, the compounded material of the thermoplastic resin is cut by shearing in the desulfurization process and dispersed to be reduced in particle size. In the reclaimed rubber obtained after the desulfurization process, the same rubber as the crosslinked rubber In the component, a compounding material of a thermoplastic resin having a maximum particle size of 250 μm or less is dispersed and contained. A thermoplastic resin compounding material having a maximum particle size of more than 250 μm is no longer a foreign substance and may cause cracks. The maximum particle size of the thermoplastic resin compounding material is preferably 230 μm or less, more preferably 205 μm or less, and even more preferably from the viewpoint of suppressing the occurrence of cracks at the interface of the thermoplastic resin compounding material in the obtained recycled rubber. It is 155 μm or less, more preferably 150 μm or less, preferably 5 μm or more, more preferably 20 μm or more, still more preferably 50 μm or more, and even more preferably 100 μm or more. The maximum particle size of the thermoplastic resin compounding material in the recycled rubber can be controlled by the shear stress or the like in the desulfurization process. The maximum particle size of the thermoplastic resin compounding material can be measured by observing the surface of the obtained recycled rubber.
　再生ゴムにおけるゴム成分の含有量は、好ましくは３０質量％以上、より好ましくは４０質量％以上であり、また、好ましくは７０質量％以下、より好ましくは６０質量％以下である。再生ゴムにおける熱可塑性樹脂の配合材料の含有量は、好ましくは２質量％以上、より好ましくは８質量％以上であり、また、好ましくは３０質量％以下、より好ましくは２０質量％以下である。 The content of the rubber component in the recycled rubber is preferably 30% by mass or more, more preferably 40% by mass or more, and preferably 70% by mass or less, more preferably 60% by mass or less. The content of the thermoplastic resin compounding material in the recycled rubber is preferably 2% by mass or more, more preferably 8% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less.
　以上の実施形態２に係る再生ゴムの製造方法によれば、熱可塑性樹脂の配合材料の存在下で架橋ゴムに剪断応力を加えて脱硫処理する際の処理温度を、熱可塑性樹脂の配合材料の融点よりも２０℃以上低い温度に設定し、そして、最大粒径が２５０μｍ以下の熱可塑性樹脂の配合材料が分散して含まれた再生ゴムを得るので、脱硫処理において熱可塑性樹脂の配合材料は溶融せず、そのため、得られる再生ゴムから得られるゴム組成物は、以下の実施例の試験評価２で示す通り、低ｔａｎδとなることから、繰り返し屈曲された際でも発熱が抑えられ、従って、伝動ベルト等の繰り返し屈曲を受けるゴム製品への適用に好適な再生ゴムを製造することができる。一般に、再生ゴムの製造において、原料の架橋ゴムに含まれる短繊維等の熱可塑性樹脂の配合材料は、通常は異物としてふるい分けやエアーフローティングテーブルにより分離されるが、実施形態２に係る再生ゴムの製造方法では、かかる熱可塑性樹脂の配合材料が、得られる再生ゴムを用いたゴム組成物における低ｔａｎδ化に寄与する。 According to the method for producing a recycled rubber according to the second embodiment, the processing temperature at the time of desulfurization treatment by applying a shear stress to the crosslinked rubber in the presence of the thermoplastic resin compounding material is set to be the same as that of the thermoplastic resin compounding material. The temperature is set to 20 ° C. or more lower than the melting point, and a recycled rubber containing a thermoplastic resin compounding material having a maximum particle size of 250 μm or less is dispersed and contained. Therefore, the rubber composition obtained from the recycled rubber obtained has a low tan δ as shown in the test evaluation 2 of the following examples, so that heat generation is suppressed even when it is repeatedly bent. A recycled rubber suitable for application to a rubber product that undergoes repeated bending, such as a transmission belt, can be produced. In general, in the production of recycled rubber, the blended material of thermoplastic resin such as short fibers contained in the raw material crosslinked rubber is usually separated as a foreign substance by sieving or an air floating table. In the production method, the blended material of the thermoplastic resin contributes to the reduction in tan δ in the rubber composition using the obtained recycled rubber.
　実施形態２に係る再生ゴムの製造方法では、脱硫処理後、必要に応じて、リファイニング、ストレーニング、シーティングを行う。 In the recycled rubber manufacturing method according to Embodiment 2, after desulfurization treatment, refining, straining, and sheeting are performed as necessary.
　実施形態２の製造方法により得られた再生ゴムは、実施形態１に係る再生ゴムと同一の構成を有していてもよく、つまり、硫黄架橋されたエチレンプロピレンジエンモノマーを含むゴム組成物を由来とし、且つゲル分率が５０～８５質量％であってもよい。 The recycled rubber obtained by the production method of Embodiment 2 may have the same configuration as the recycled rubber according to Embodiment 1, that is, derived from a rubber composition containing a sulfur-crosslinked ethylene propylene diene monomer. And the gel fraction may be 50 to 85% by mass.
　実施形態２の製造方法により得られた再生ゴムは、実施形態１と同様に、再生ゴムに含まれるのと同一又は異なるバージンゴムがブレンドされてベースゴム材料とされ、或いは、そのままベースゴム材料とされ、そして、架橋剤を含むゴム配合剤が配合され、例えば、実施形態１において図１に示したラップドＶベルトＢのような伝動ベルト、コンベヤベルト、タイヤ、ホース等のゴム製品を構成するゴム組成物として用いられる。実施形態２の製造方法により得られた再生ゴムは、これを用いたゴム組成物が低ｔａｎδとなることから、繰り返し屈曲された際でも発熱が抑えられる。従って、実施形態２の製造方法により得られた再生ゴムを用いたゴム組成物により、繰り返し屈曲される伝動ベルトのベルト本体の少なくとも一部を構成することが好適である。 The reclaimed rubber obtained by the production method of Embodiment 2 is blended with the same or different virgin rubber as contained in the reclaimed rubber to form a base rubber material as in Embodiment 1, or as it is with the base rubber material as it is. Then, a rubber compounding agent containing a crosslinking agent is compounded, and for example, a rubber constituting a rubber product such as a transmission belt such as a wrapped V belt B shown in FIG. 1 in Embodiment 1, a conveyor belt, a tire, a hose, etc. Used as a composition. The recycled rubber obtained by the production method of Embodiment 2 has a low tan δ rubber composition using the rubber, so that heat generation can be suppressed even when it is repeatedly bent. Therefore, it is preferable that at least a part of the belt body of the transmission belt bent repeatedly is constituted by the rubber composition using the recycled rubber obtained by the manufacturing method of Embodiment 2.
　実施形態２の製造方法により得られた再生ゴムが用いられたゴム組成物の列理方向における２５℃での貯蔵弾性係数Ｅ’は、好ましくは１２ＭＰａ以上、より好ましくは１５ＭＰａ以上であり、また、好ましくは７０ＭＰａ以下、より好ましくは４０ＭＰａ以下である。１００℃での貯蔵弾性係数Ｅ’は、好ましくは８ＭＰａ以上、より好ましくは１０ＭＰａ以上であり、また、好ましくは５０ＭＰａ以下、より好ましくは３０ＭＰａ以下である。１２０℃での貯蔵弾性係数Ｅ’は、好ましくは７ＭＰａ以上、より好ましくは９ＭＰａ以上であり、また、好ましくは５０ＭＰａ以下、より好ましくは２５ＭＰａ以下である。 The storage elastic modulus E ′ at 25 ° C. in the line direction of the rubber composition using the recycled rubber obtained by the production method of Embodiment 2 is preferably 12 MPa or more, more preferably 15 MPa or more, Preferably it is 70 MPa or less, More preferably, it is 40 MPa or less. The storage elastic modulus E ′ at 100 ° C. is preferably 8 MPa or more, more preferably 10 MPa or more, and preferably 50 MPa or less, more preferably 30 MPa or less. The storage elastic modulus E ′ at 120 ° C. is preferably 7 MPa or more, more preferably 9 MPa or more, and preferably 50 MPa or less, more preferably 25 MPa or less.
　実施形態２の製造方法により得られた再生ゴムの列理方向における２５℃での損失係数ｔａｎδは、好ましくは０．０６以上、より好ましくは０．０８以上であり、また、好ましくは０．２０以下、より好ましくは０．１８以下である。１００℃での損失係数ｔａｎδは、好ましくは０．０４以上、より好ましくは０．０６以上であり、また、好ましくは０．１５以下、より好ましくは０．１２以下である。１２０℃での損失係数ｔａｎδは、好ましくは０．０４以上、より好ましくは０．０６以上であり、また、好ましくは０．１４以下、より好ましくは０．１１以下である。 The loss factor tan δ at 25 ° C. in the row direction of the recycled rubber obtained by the production method of Embodiment 2 is preferably 0.06 or more, more preferably 0.08 or more, and preferably 0.20. Below, more preferably 0.18 or less. The loss coefficient tan δ at 100 ° C. is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0.15 or less, more preferably 0.12 or less. The loss coefficient tan δ at 120 ° C. is preferably 0.04 or more, more preferably 0.06 or more, and preferably 0.14 or less, more preferably 0.11 or less.
　貯蔵弾性係数Ｅ’及び損失係数ｔａｎδは、ＪＩＳＫ６３９４に基づいて求められる。 The storage elastic modulus E ′ and the loss coefficient tan δ are obtained based on JISK6394.
　［試験評価１］
　（ゴム組成物）
　架橋ゴムとして、硫黄架橋したＥＰＤＭ組成物（ゴム成分であるＥＰＤＭの含有量：５０質量％）を準備した。そして、その架橋ゴムを平均粒径１５０μｍに粉砕して粉状乃至粒状にした後、二軸押出機（日本製鋼所社製　型番：ＴＥＸ３０α，スクリュー径：３０ｍｍ，スクリュー長さ：１７８５ｍｍ）に投入し、粉状乃至粒状の架橋ゴムに剪断応力を加えて脱硫処理を施し、冷却して再生ゴムを調整した。このとき、処理温度、スクリュー回転数（剪断応力）、及び処理時間の変量によりゲル分率を制御した。具体的には、処理温度２００℃及びスクリュー回転数４００ｒｐｍ（剪断応力７ＭＰａ）としてゲル分率が７０質量％の再生ゴム１を得た。処理温度２２０℃及びスクリュー回転数４００ｒｐｍ（剪断応力８ＭＰａ）としてゲル分率が５２質量％の再生ゴム２を得た。処理温度２６０℃及びスクリュー回転数６００ｒｐｍ（剪断応力１１ＭＰａ）としてゲル分率が４５質量％の再生ゴム３を得た。なお、ゲル分率は、上記のトルエン膨潤法により求めた。 [Test Evaluation 1]
(Rubber composition)
As a crosslinked rubber, a sulfur-crosslinked EPDM composition (content of EPDM as a rubber component: 50% by mass) was prepared. The crosslinked rubber is pulverized to an average particle size of 150 μm to form powder or granule, and then charged into a twin screw extruder (model number: TEX30α, screw diameter: 30 mm, screw length: 1785 mm, manufactured by Nippon Steel Works). The powdered or granular crosslinked rubber was subjected to a desulfurization treatment by applying a shear stress, and cooled to prepare a recycled rubber. At this time, the gel fraction was controlled by changing the processing temperature, screw rotation speed (shear stress), and processing time. Specifically, a recycled rubber 1 having a gel fraction of 70% by mass at a treatment temperature of 200 ° C. and a screw rotation speed of 400 rpm (shear stress of 7 MPa) was obtained. A recycled rubber 2 having a gel fraction of 52% by mass was obtained at a treatment temperature of 220 ° C. and a screw rotation speed of 400 rpm (shear stress of 8 MPa). A recycled rubber 3 having a gel fraction of 45% by mass was obtained at a treatment temperature of 260 ° C. and a screw rotation speed of 600 rpm (shear stress of 11 MPa). The gel fraction was determined by the toluene swelling method described above.
　再生ゴム１～３を用い、以下の実施例１-１～１-４及び比較例１-１～１-２の未架橋ゴム組成物を作製した。それぞれの構成については表１にも示す。 Using the recycled rubbers 1 to 3, uncrosslinked rubber compositions of the following Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2 were prepared. Each configuration is also shown in Table 1.
　＜実施例１-１＞
　再生ゴム１の２００質量部（ゴム成分のＥＰＤＭ１００質量部）に対し、ゴム配合剤として、ステアリン酸（日油社製　商品名：ビーズ　ステアリン酸　つばき）１質量部、酸化亜鉛（堺化学工業社製　商品名：酸化亜鉛３種）５質量部、軟化剤（出光興産社製　商品名：ダイアナプロセスＰＷ－９０）２０質量部、硫黄（軽井沢精錬所社製　油処理硫黄）３質量部、チウラム系加硫促進剤（大内新興化学社製　商品名：ノクセラーＴＥＴ－Ｇ）２質量部、及びチアゾール系加硫促進剤（大内新興化学社製　商品名：ノクセラーＤＭ－Ｐ）１質量部を配合して混練することにより得た未架橋ゴム組成物を実施例１-１とした。 <Example 1-1>
For 200 parts by mass of recycled rubber 1 (100 parts by mass of EPDM as a rubber component), 1 part by mass of stearic acid (manufactured by NOF Corporation, trade name: bead stearic acid Tsubaki), zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) Product name: 5 parts by mass of zinc oxide (3 types), softener (made by Idemitsu Kosan Co., Ltd., product name: Diana Process PW-90), 20 parts by mass, sulfur (oil treated sulfur by Karuizawa Smelter), 3 parts by mass, 2 parts by weight of a sulfur accelerator (trade name: Noxeller TET-G manufactured by Ouchi Shinsei Chemical Co., Ltd.) and 1 part by weight of a thiazole vulcanization accelerator (trade name: Noxeller DM-P manufactured by Ouchi Shinsei Chemical Co., Ltd.) An uncrosslinked rubber composition obtained by kneading was designated as Example 1-1.
　＜実施例１-２＞
　再生ゴム１の２００質量部（ゴム成分のＥＰＤＭ１００質量部）に対し、ゴム配合剤として、ステアリン酸１質量部、酸化亜鉛５質量部、軟化剤２０質量部、有機過酸化物（日油社製　商品名：パーブチルＰ－４０　純度４０質量％）８質量部（有効成分３．２質量部）を配合して混練することにより得た未架橋ゴム組成物を実施例１-２とした。 <Example 1-2>
For 200 parts by mass of recycled rubber 1 (100 parts by mass of EPDM as a rubber component), 1 part by mass of stearic acid, 5 parts by mass of zinc oxide, 20 parts by mass of softening agent, organic peroxide (manufactured by NOF Corporation) Product name: Perbutyl P-40 Purity 40% by mass) An uncrosslinked rubber composition obtained by blending and kneading 8 parts by mass (active ingredient 3.2 parts by mass) was defined as Example 1-2.
　＜実施例１-３＞
　再生ゴム２を用いたことを除いて実施例１と同一構成の未架橋ゴム組成物を実施例１-３とした。 <Example 1-3>
An uncrosslinked rubber composition having the same structure as in Example 1 except that the recycled rubber 2 was used was designated as Example 1-3.
　＜実施例１-４＞
　再生ゴム１の１００質量部（ゴム成分のＥＰＤＭ５０質量部）に対し、ＥＰＤＭのバージンゴム（ＪＳＲ社製　商品名：ＥＰ３３）５０質量部をブレンドし、それらに含まれるゴム成分１００質量部に対し、ゴム配合剤として、ＨＡＦカーボンブラック（東海カーボン社製　商品名：シースト３）５０質量部、ステアリン酸１質量部、酸化亜鉛５質量部、軟化剤２０質量部、硫黄３質量部、チウラム系加硫促進剤２質量部、及びチアゾール系加硫促進剤１質量部を配合して混練することにより得た未架橋ゴム組成物を実施例１-４とした。 <Example 1-4>
50 parts by mass of virgin rubber (trade name: EP33 manufactured by JSR) of EPDM is blended with 100 parts by mass of recycled rubber 1 (EPDM 50 parts by mass of rubber component), and 100 parts by mass of rubber component contained therein, As a rubber compounding agent, 50 parts by mass of HAF carbon black (trade name: SEAST 3 manufactured by Tokai Carbon Co., Ltd.), 1 part by mass of stearic acid, 5 parts by mass of zinc oxide, 20 parts by mass of a softening agent, 3 parts by mass of sulfur, and thiuram-based vulcanization An uncrosslinked rubber composition obtained by blending 2 parts by mass of an accelerator and 1 part by mass of a thiazole vulcanization accelerator and kneading was designated as Example 1-4.
　＜比較例１-１＞
　再生ゴム３を用いたことを除いて実施例１と同一構成の未架橋ゴム組成物を比較例１-１とした。 <Comparative Example 1-1>
A non-crosslinked rubber composition having the same structure as in Example 1 except that the recycled rubber 3 was used was designated as Comparative Example 1-1.
　＜比較例１-２＞
　再生ゴム３を用いたことを除いて実施例２と同一構成の未架橋ゴム組成物を比較例１-２とした。 <Comparative Example 1-2>
A non-crosslinked rubber composition having the same structure as in Example 2 except that the recycled rubber 3 was used was designated as Comparative Example 1-2.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　なお、実施例１-１、１-３、及び１-４、並びに比較例１-１のゴム組成物は、硫黄架橋系であることから、これらを架橋させて得られるゴム組成物は、残留した硫黄架橋によるゲル分と、追加の硫黄架橋に由来する硫黄結合とを有することとなる。一方、実施例１-２及び比較例１-２のゴム組成物は、有機過酸化物架橋系であることから、これらを架橋させて得られるゴム組成物は、残留した硫黄架橋によるゲル分と、有機過酸化物架橋に由来するＣ－Ｃ結合とを有することとなる。 In addition, since the rubber compositions of Examples 1-1, 1-3, and 1-4 and Comparative Example 1-1 are sulfur cross-linked systems, the rubber compositions obtained by cross-linking these are residual The gel content due to sulfur cross-linking and the sulfur bond derived from the additional sulfur cross-linking are provided. On the other hand, since the rubber compositions of Example 1-2 and Comparative Example 1-2 are organic peroxide crosslinking systems, the rubber composition obtained by crosslinking them has a gel content due to residual sulfur crosslinking. And a C—C bond derived from organic peroxide crosslinking.
　（試験評価方法）
　＜損失係数ｔａｎδ＞
　実施例１-１～１-４及び比較例１-１～１-２のそれぞれの未架橋ゴム組成物について、シート状のゴムシートを成形加硫し、ＪＩＳ Ｋ６３９４に基づいて、振動周波数１０Ｈｚ及び動歪１．０％とし、その列理方向の１００℃における損失係数ｔａｎδを求めた。 (Test evaluation method)
<Loss factor tanδ>
For each of the uncrosslinked rubber compositions of Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2, a sheet-like rubber sheet was molded and vulcanized. Based on JIS K6394, a vibration frequency of 10 Hz and The loss coefficient tan δ at 100 ° C. in the direction of the line was determined with a dynamic strain of 1.0%.
　＜ベルト耐久試験＞
　実施例１-１～１-４及び比較例１-１～１-２のそれぞれの未架橋ゴム組成物により圧縮ゴム層、接着ゴム層、及び伸張ゴム層を構成したラップドＶベルトを作製した。なお、心線にはポリエステル繊維の撚り糸、及び補強布には綿の織布をそれぞれ用いた。 <Belt durability test>
Wrapped V-belts each comprising a compressed rubber layer, an adhesive rubber layer, and an extended rubber layer were produced from the uncrosslinked rubber compositions of Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2. A polyester fiber twisted yarn was used for the core wire, and a cotton woven fabric was used for the reinforcing fabric.
　図３はベルト走行試験機３０のプーリレイアウトを示す。 FIG. 3 shows a pulley layout of the belt running test machine 30.
　ベルト走行試験機３０は、プーリ径８０ｍｍの駆動プーリ３１と、その下方に設けられたプーリ径８０ｍｍの従動プーリ３２とを有する。従動プーリ３２は上下可動に構成されており、従動プーリ３２に錘（デッドウェイト）を吊すことにより、駆動プーリ３１及び従動プーリ３２に巻き掛けられたラップドＶベルトＢに張力を負荷できるように構成されている。 The belt running test machine 30 includes a driving pulley 31 having a pulley diameter of 80 mm and a driven pulley 32 having a pulley diameter of 80 mm provided below the driving pulley 31. The driven pulley 32 is configured to be movable up and down, and by suspending a weight (dead weight) from the driven pulley 32, the driven pulley 32 and the wrapped V-belt B wound around the driven pulley 32 can be loaded with tension. Has been.
　実施例１-１～１-４及び比較例１-１～１-２のそれぞれの未架橋ゴム組成物を用いて作製したラップドＶベルトＢについて、駆動プーリ３１及び従動プーリ３２に巻き掛けると共に、従動プーリ３２に８０ｋｇの錘を下げてラップドＶベルトＢに張力を負荷し、従動プーリ３２に回転負荷を与えずに、常温下、駆動プーリ３１を３５００ｒｐｍの回転数で回転させてラップドＶベルトＢをベルト走行させ、定期的にベルト走行を停止してクラックの発生の有無を目視で確認し、クラックの発生が確認された時点でベルト走行を終了した。そして、ベルト寿命を、比較例１-１のクラック発生までのベルト走行時間を１００とした相対値として評価した。また、非接触型の表面温度計を用い、ベルト走行時におけるベルト温度を測定し、雰囲気温度との温度差の最大値を求めた。 About wrapped V-belt B produced using the uncrosslinked rubber compositions of Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2, the drive pulley 31 and the driven pulley 32 were wound around, A weight of 80 kg is lowered on the driven pulley 32 to apply tension to the wrapped V-belt B, and without applying a rotational load to the driven pulley 32, the driving pulley 31 is rotated at a rotational speed of 3500 rpm at room temperature to wrap the wrapped V-belt B. The belt running was periodically stopped, the belt running was periodically stopped and visually checked for the occurrence of cracks, and the belt running was terminated when the occurrence of cracks was confirmed. The belt life was evaluated as a relative value with the belt running time until crack occurrence in Comparative Example 1-1 as 100. Further, the belt temperature during belt running was measured using a non-contact type surface thermometer, and the maximum value of the temperature difference from the ambient temperature was determined.
　（試験評価結果）
　試験結果を表１に示す。 (Test evaluation results)
The test results are shown in Table 1.
　ゲル分率が４５質量％と低い再生ゴム３を用いた硫黄架橋系の比較例１-１の場合、ｔａｎδが大きく（０．１７５）、また、ベルト走行時の発熱も大きく（＋４４℃）、更に、ベルト走行時に早期にクラックが発生してベルト寿命が短かった（１００）。 In the case of Comparative Example 1-1 of the sulfur crosslinking system using the regenerated rubber 3 having a low gel fraction of 45% by mass, tan δ is large (0.175), and heat generation during belt running is large (+ 44 ° C.). Furthermore, cracks occurred early during belt running, resulting in a short belt life (100).
　ゲル分率が再生ゴム３よりも高い５２質量％である再生ゴム２を用いた硫黄架橋系の実施例１-３の場合、比較例１-１の場合に比べると、ｔａｎδが低く（０．１２５）、また、ベルト走行時の発熱も小さく（＋２９℃）、更に、ベルト寿命も長かった（１４２）。 In the case of Example 1-3 of the sulfur crosslinking system using the regenerated rubber 2 having a gel fraction of 52% by mass higher than that of the regenerated rubber 3, tan δ is lower than that in the case of Comparative Example 1-1 (0. 125), and the heat generation during running of the belt was small (+ 29 ° C.), and the belt life was also long (142).
　ゲル分率が再生ゴム２よりも更に高い７０質量％である再生ゴム１を用いた硫黄架橋系の実施例１-１の場合、実施例１-２の場合に比べても、ｔａｎδが一層低く（０．１０７）、また、ベルト走行時の発熱も一層小さく（＋２５℃）、更に、ベルト寿命も一層長かった（１４９）。 In the case of Example 1-1 of the sulfur cross-linking system using the regenerated rubber 1 having a gel fraction of 70% by mass higher than that of the regenerated rubber 2, tan δ is much lower than in the case of Example 1-2. In addition, the heat generation during belt running was smaller (+ 25 ° C.), and the belt life was longer (149).
　ゲル分率が４５質量％と低い再生ゴム３を用いた有機過酸化物架橋系の比較例１-２の場合、ｔａｎδが０．１５９、また、ベルト走行時の発熱が＋３８℃、更に、ベルト寿命が１２０であり、比較例１-１の場合よりも優れるものの、大きな改善がなされているとは言えない。 In the case of Comparative Example 1-2 of the organic peroxide crosslinking system using the regenerated rubber 3 having a low gel fraction of 45% by mass, tan δ is 0.159, the heat generated during belt running is + 38 ° C., and the belt Although the lifetime is 120, which is superior to that of Comparative Example 1-1, it cannot be said that a great improvement has been made.
　ゲル分率が７０質量％である再生ゴム１を用いた有機過酸化物架橋系の実施例１-２の場合、実施例１-１の場合と比べても、ｔａｎδがより一層低く（０．０８９）、また、ベルト走行時の発熱もより一層小さく（＋２１℃）、更に、ベルト寿命もより一層長かった（１６８）。 In the case of Example 1-2 of the organic peroxide cross-linking system using the regenerated rubber 1 having a gel fraction of 70% by mass, tan δ is much lower than that in Example 1-1 (0. In addition, the heat generation during running of the belt was much smaller (+ 21 ° C.), and the belt life was even longer (168).
　また、再生ゴム２とＥＰＤＭのバージンゴムとをブレンドした硫黄架橋系の実施例１-４の場合、比較例１-１及び１-２の場合と比べても、ｔａｎδが低く（０．１１９）、また、ベルト走行時の発熱も小さく（＋２８℃）、更に、ベルト寿命も長かった（１５２）。 Further, in the case of Example 1-4 of the sulfur crosslinking system in which recycled rubber 2 and EPDM virgin rubber were blended, tan δ was low (0.119) as compared with Comparative Examples 1-1 and 1-2. Also, the heat generated during belt running was small (+ 28 ° C.), and the belt life was also long (152).
　実施例１-１～１-４のゴム組成物を用いて作製したラップドＶベルトでは、再生ゴム１及び２における残留した硫黄架橋による適量のゲル分が存在することによりゴム弾性が維持され、その結果、ベルト耐久試験において優れたベルト寿命が得られているものと推測される。また、再生ゴム２とＥＰＤＭのバージンゴムとをブレンドした場合でも、残留した硫黄架橋のゲル分が適度に分散することによりゴム弾性が得られ、その結果、ベルト耐久試験において優れたベルト寿命が得られているものと推測される。 In the wrapped V-belts produced using the rubber compositions of Examples 1-1 to 1-4, rubber elasticity is maintained due to the presence of an appropriate amount of gel due to residual sulfur crosslinking in the recycled rubbers 1 and 2, As a result, it is presumed that an excellent belt life is obtained in the belt durability test. Even when the recycled rubber 2 and EPDM virgin rubber are blended, the rubber elasticity is obtained by appropriately dispersing the remaining sulfur cross-linked gel, and as a result, excellent belt life is obtained in the belt durability test. It is presumed that
　実施例１-１～１-４のゴム組成物において用いた再生ゴム１及び２は、硫黄架橋したＥＰＤＭを脱硫処理することにより得られるが、ＥＰＤＭのバージンゴムを用いるよりも優れた性能を実現することができる。 Recycled rubbers 1 and 2 used in the rubber compositions of Examples 1-1 to 1-4 were obtained by desulfurization treatment of sulfur-crosslinked EPDM, but achieved performance superior to that of using EPDM virgin rubber. can do.
　［試験評価２］
　（再生ゴム）
　＜実施例２-１＞
　表２に示すように、ＥＰＤＭ（ＪＳＲ社製　商品名：ＥＰ５１）を原料ゴムとし、この原料ゴム１００質量部に対し、ＨＡＦカーボンブラック（東海カーボン社製　商品名：シースト３）５０質量部、ステアリン酸（日本油脂社製　商品名：ビーズ　ステアリン酸　つばき）１質量部、酸化亜鉛（堺化学社製　商品名：酸化亜鉛３種）５質量部、軟化剤（出光興産社製　商品名：ダイアナプロセスオイルＰＷ－９０）１５質量部、硫黄（軽井沢製錬所社製　商品名：油処理硫黄）３質量部、チウラム系加硫促進剤（大内新興化学社製　商品名：ノクセラーＴＥＴ－Ｇ）２質量部、チアゾール系加硫促進剤（大内新興化学社製　商品名：ノクセラーＤＭ－Ｐ）１質量部、及びナイロン６６短繊維（旭化成社製　商品名：レオナ６６，融点２６０℃）を配合して硫黄架橋した架橋ゴムを準備した。 [Test evaluation 2]
(Recycled rubber)
<Example 2-1>
As shown in Table 2, EPDM (trade name: EP51 manufactured by JSR Corporation) is used as a raw rubber, and 100 parts by weight of this raw rubber is 50 parts by weight of HAF carbon black (trade name: Seast 3 manufactured by Tokai Carbon Co., Ltd.), stearin. 1 part by weight of acid (Nippon Yushi Co., Ltd., trade name: beads, stearic acid Tsubaki), 5 parts by weight of zinc oxide (trade name: Zinc Oxide, 3 types), softener (made by Idemitsu Kosan Co., Ltd., trade name: Diana Process Oil) PW-90) 15 parts by mass, sulfur (manufactured by Karuizawa Smelter Co., Ltd., trade name: oil-treated sulfur) 3 parts by mass, thiuram vulcanization accelerator (trade name: Noxeller TET-G, produced by Ouchi Shinsei Chemical Co., Ltd.) 1 part by weight of a thiazole-based vulcanization accelerator (trade name: Noxeller DM-P, manufactured by Ouchi Shinsei Chemical Co., Ltd.) and nylon 66 short fiber (trade name: Leona 66, melting point 260 ° C., manufactured by Asahi Kasei Co., Ltd.) To prepare a cross-linked rubber and yellow cross.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　架橋ゴムを平均粒径４００μｍに粉砕した後、二軸押出機（日本製鋼所社製　型番：ＴＥＸ３０α，スクリュー径：３０ｍｍ，スクリュー長さ：１７８５ｍｍ）に投入し、処理温度をナイロン６６短繊維の融点の２６０℃よりも６０℃低い２００℃及びスクリューの回転数を６００ｒｐｍ（剪断応力：１４ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施し、冷却して得られた再生ゴムを実施例２-１とした。 After the crosslinked rubber is pulverized to an average particle size of 400 μm, it is put into a twin screw extruder (manufactured by Nippon Steel Works, model number: TEX30α, screw diameter: 30 mm, screw length: 1785 mm), and the processing temperature is the melting point of nylon 66 short fiber A regenerated rubber obtained by subjecting a crosslinked rubber to a desulfurization treatment by applying a shear stress to a crosslinked rubber at 200 ° C., which is 60 ° C. lower than 260 ° C. and a screw rotation speed of 600 rpm (shear stress: 14 MPa), is obtained in Example 2- It was set to 1.
　実施例２-１の再生ゴムについて、カッターを用いて切断し、マイクロスコープ（キーエンス社製　型番：ＶＨＸ２０００）を用い、その断面の３カ所を２００倍に拡大して観察したところ、図１に示すような形態が見られ、そして、最も大きいナイロン短繊維の外径（最大外径）を計測モードにより測定したところ１４８μｍであった。また、上記のトルエン膨潤法によりゲル分率を求めたところ６２質量％であった。 The recycled rubber of Example 2-1 was cut using a cutter, and observed using a microscope (Keyence Co., Ltd., model number: VHX2000) by magnifying three portions of the cross section by 200 times, as shown in FIG. Such a form was seen, and when the outer diameter (maximum outer diameter) of the largest nylon short fiber was measured by the measurement mode, it was 148 μm. Moreover, it was 62 mass% when the gel fraction was calculated | required by said toluene swelling method.
　＜実施例２-２＞
　スクリューの回転数を４００ｒｐｍ（剪断応力：８ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを実施例２-２とした。 <Example 2-2>
A recycled rubber obtained in the same manner as in Example 2-1 except that the screw was rotated at 400 rpm (shear stress: 8 MPa) and subjected to desulfurization treatment by applying shear stress to the crosslinked rubber was obtained as Example 2-2. It was.
　実施例２-２の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ２０２μｍであった。また、ゲル分率は６８質量％であった。 For the recycled rubber of Example 2-2, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 202 μm. Moreover, the gel fraction was 68 mass%.
　＜実施例２-３＞
　処理温度をナイロン６６短繊維の融点の２６０℃よりも３０℃低い２３０℃及びスクリューの回転数を６００ｒｐｍ（剪断応力：１２ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを実施例２-３とした。 <Example 2-3>
Except that the treatment temperature was 230 ° C., which is 30 ° C. lower than the melting point of nylon 66 short fiber, 230 ° C., and the screw rotation speed was 600 rpm (shear stress: 12 MPa), and the desulfurization treatment was performed by applying shear stress to the crosslinked rubber. A recycled rubber obtained in the same manner as in Example 2-1 was designated as Example 2-3.
　実施例２-３の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ１５１μｍであった。また、ゲル分率は５５質量％であった。 For the recycled rubber of Example 2-3, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and was found to be 151 μm. Moreover, the gel fraction was 55 mass%.
　＜実施例２-４＞
　処理温度をナイロン６６短繊維の融点の２６０℃よりも６０℃低い２００℃及びスクリューの回転数を２００ｒｐｍ（剪断応力：６ＭＰａ）として架橋ゴムに脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを実施例２-４とした。 <Example 2-4>
Example 2-1 except that the crosslinked rubber was subjected to a desulfurization treatment at a treatment temperature of 200 ° C., which is 60 ° C. lower than the melting point of nylon 66 short fiber, 260 ° C., and a screw rotation speed of 200 rpm (shear stress: 6 MPa). Recycled rubber obtained in the same manner as in Example 2-4 was used.
　実施例２-４の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ２２７μｍであった。また、ゲル分率は７５質量％であった。 For the recycled rubber of Example 2-4, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 227 μm. Moreover, the gel fraction was 75 mass%.
　＜実施例２-５＞
　処理温度をナイロン６６短繊維の融点の２６０℃よりも２０℃低い２４０℃及びスクリューの回転数を６００ｒｐｍ（剪断応力：１３ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを実施例２-５とした。 <Example 2-5>
Except that the treatment temperature was 240 ° C., which is 20 ° C. lower than the melting point of nylon 66 short fiber of 260 ° C., and the screw rotation speed was 600 rpm (shear stress: 13 MPa). A recycled rubber obtained in the same manner as in Example 2-1 was designated as Example 2-5.
　実施例２-５の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ１５５μｍであった。また、ゲル分率は５１質量％であった。 For the recycled rubber of Example 2-5, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 155 μm. Moreover, the gel fraction was 51 mass%.
　＜比較例２-１＞
　架橋ゴムとしてナイロン６６短繊維が配合されていないものを用い、処理温度を２００℃及びスクリューの回転数を４００ｒｐｍ（剪断応力：５ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを比較例２-１とした。 <Comparative Example 2-1>
Using a non-blended nylon 66 short fiber as the cross-linked rubber, applying a shear stress to the cross-linked rubber with a treatment temperature of 200 ° C. and a screw speed of 400 rpm (shear stress: 5 MPa). A recycled rubber obtained in the same manner as in Example 2-1 was used as Comparative Example 2-1.
　比較例２-１の再生ゴムについて、ゲル分率は７８質量％であった。 The gel fraction of the recycled rubber of Comparative Example 2-1 was 78% by mass.
　＜比較例２-２＞
　処理温度をナイロン６６短繊維の融点の２６０℃よりも１０℃低い２５０℃及びスクリューの回転数を６００ｒｐｍ（剪断応力：１０ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを比較例２-２とした。 <Comparative Example 2-2>
Except that the treatment temperature was 250 ° C., which is 10 ° C. lower than the melting point of nylon 66 short fiber, 260 ° C., and the screw rotation speed was 600 rpm (shear stress: 10 MPa), and the desulfurization treatment was performed by applying shear stress to the crosslinked rubber A recycled rubber obtained in the same manner as in Example 2-1 was used as Comparative Example 2-2.
　比較例２-２の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ１４７μｍであった。また、ゲル分率は４６質量％であった。 For the recycled rubber of Comparative Example 2-2, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 147 μm. Moreover, the gel fraction was 46 mass%.
　＜比較例２-３＞
　スクリューの回転数を１００ｒｐｍ（剪断応力：５ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを比較例２-３とした。 <Comparative Example 2-3>
A recycled rubber obtained in the same manner as in Example 2-1 except that the rotational speed of the screw was 100 rpm (shear stress: 5 MPa) and the crosslinked rubber was subjected to desulfurization treatment by applying shear stress was used as Comparative Example 2-3. It was.
　比較例２-３の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ３１１μｍであった。また、ゲル分率は８３質量％であった。 For the recycled rubber of Comparative Example 2-3, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 311 μm. Moreover, the gel fraction was 83 mass%.
　＜比較例２-４＞
　処理温度をナイロン６６短繊維の融点の２６０℃よりも１０℃低い２５０℃及びスクリューの回転数を１００ｒｐｍ（剪断応力：４ＭＰａ）として架橋ゴムに剪断応力を加えて脱硫処理を施したことを除いて実施例２-１と同様にして得られた再生ゴムを比較例２-４とした。 <Comparative Example 2-4>
The treatment temperature was 250 ° C., which is 10 ° C. lower than the melting point of nylon 66 short fiber, 260 ° C., and the rotational speed of the screw was 100 rpm (shear stress: 4 MPa). A recycled rubber obtained in the same manner as in Example 2-1 was designated as Comparative Example 2-4.
　比較例２-４の再生ゴムについて、実施例２-１と同様にしてナイロン短繊維の最大外径を測定したところ３０２μｍであった。また、ゲル分率は７０質量％であった。 For the recycled rubber of Comparative Example 2-4, the maximum outer diameter of the nylon short fiber was measured in the same manner as in Example 2-1, and it was 302 μm. Moreover, the gel fraction was 70 mass%.
　（試験評価方法）
　実施例２-１～２-５及び比較例２-１～２-４のそれぞれの再生ゴムについて、表３に示すように、再生ゴム２００質量部（ゴム成分のＥＰＤＭ１００質量部）に対し、ステアリン酸（日本油脂社製　商品名：ビーズ　ステアリン酸　つばき）１質量部、酸化亜鉛（堺化学社製　商品名：酸化亜鉛３種）５質量部、軟化剤（出光興産社製　商品名：ダイアナプロセスオイルＰＷ－９０）１５質量部、硫黄（軽井沢製錬所社製　商品名：油処理硫黄）３質量部、チウラム系加硫促進剤（大内新興化学社製　商品名：ノクセラーＴＥＴ－Ｇ）２質量部、及びチアゾール系加硫促進剤（大内新興化学社製　商品名：ノクセラーＤＭ－Ｐ）１質量部を配合した未架橋ゴム組成物を準備した。 (Test evaluation method)
As shown in Table 3, with respect to each recycled rubber of Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-4, stearin was used with respect to 200 parts by weight of recycled rubber (100 parts by weight of EPDM rubber component). 1 part by weight of acid (Nippon Yushi Co., Ltd., trade name: beads, stearic acid Tsubaki), 5 parts by weight of zinc oxide (trade name: Zinc Oxide, 3 types), softener (made by Idemitsu Kosan Co., Ltd., trade name: Diana Process Oil) PW-90) 15 parts by mass, sulfur (manufactured by Karuizawa Smelter Co., Ltd., trade name: oil-treated sulfur) 3 parts by mass, thiuram vulcanization accelerator (trade name: Noxeller TET-G, produced by Ouchi Shinsei Chemical Co., Ltd.) And an uncrosslinked rubber composition containing 1 part by weight of a thiazole vulcanization accelerator (trade name: Noxeller DM-P, manufactured by Ouchi Shinsei Chemical Co., Ltd.) was prepared.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　＜動的粘弾性試験＞
　実施例２-１～２-５及び比較例２-１～２-４のそれぞれの再生ゴムを用いた未架橋ゴム組成物について、シート状のゴムシートを成形加硫し、ＪＩＳ Ｋ６３９４に基づいて、振動周波数１０Ｈｚ及び動歪１．０％とし、その列理方向の２５℃、１００℃、及び１２０℃における貯蔵弾性係数Ｅ’及び損失係数ｔａｎδを測定した。 <Dynamic viscoelasticity test>
For the uncrosslinked rubber compositions using the reclaimed rubbers of Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-4, a sheet-like rubber sheet was molded and vulcanized, based on JIS K6394. The storage elastic modulus E ′ and the loss coefficient tan δ were measured at 25 ° C., 100 ° C., and 120 ° C. in the linear direction, with a vibration frequency of 10 Hz and a dynamic strain of 1.0%.
　＜ベルト耐久試験＞
　実施例２-１～２-５及び比較例２-１～２-４のそれぞれの再生ゴムを用いた未架橋ゴム組成物により圧縮ゴム層、接着ゴム層、及び伸張ゴム層を構成したラップドＶベルトを作製し、試験評価１と同様のベルト耐久試験を実施した。そして、ベルト寿命を、比較例２-１のクラック発生までのベルト走行時間を１００とした相対値として評価した。 <Belt durability test>
Wrapped V in which a compressed rubber layer, an adhesive rubber layer, and an extended rubber layer are constituted by an uncrosslinked rubber composition using each of the recycled rubbers of Examples 2-1 to 2-5 and Comparative Examples 2-1 to 2-4 A belt was prepared, and a belt durability test similar to Test Evaluation 1 was performed. The belt life was evaluated as a relative value with the belt running time until crack occurrence in Comparative Example 2-1 being 100.
　（試験評価結果）
　試験結果を表４及び５に示す。 (Test evaluation results)
The test results are shown in Tables 4 and 5.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　表４及び５によれば、ナイロン６６短繊維を含む実施例２-１～２-５並びに比較例２-３～２-４は、ナイロン６６短繊維を含まない比較例２-１に比べて、２５℃、１００℃、及び１２０℃のいずれにおいても貯蔵弾性係数Ｅ’が高く、且つ損失係数ｔａｎδが低く、また、ベルト耐久性が優れることが分かる。また、比較例２-２は、２５℃における貯蔵弾性係数Ｅ’だけが比較例２-１よりも低いものの、それ以外では、比較例２-１よりも貯蔵弾性係数Ｅ’が高く、且つ損失係数ｔａｎδが低く、また、ベルト耐久性が優れることが分かる。 According to Tables 4 and 5, Examples 2-1 to 2-5 containing Nylon 66 short fibers and Comparative Examples 2-3 to 2-4 were compared with Comparative Example 2-1 containing no Nylon 66 short fibers. At 25 ° C., 100 ° C., and 120 ° C., the storage elastic modulus E ′ is high, the loss coefficient tan δ is low, and the belt durability is excellent. In Comparative Example 2-2, only the storage elastic modulus E ′ at 25 ° C. is lower than that of Comparative Example 2-1, but otherwise, the storage elastic modulus E ′ is higher than that of Comparative Example 2-1, and the loss. It can be seen that the coefficient tan δ is low and the belt durability is excellent.
　比較例２-１では、ナイロン６６短繊維を含まないため、相対的に貯蔵弾性率が低く且つｔａｎδが高く、その結果、屈曲時の発熱が大きく、劣化の進行が大きいものと推測される。 Comparative Example 2-1 does not contain nylon 66 short fibers, and therefore has a relatively low storage elastic modulus and a high tan δ. As a result, it is presumed that heat generation during bending is large and deterioration proceeds greatly.
　実施例２-１～２-５は、比較例２-１～２-４に比べて、ベルト耐久性が優れることが分かる。 It can be seen that Examples 2-1 to 2-5 have better belt durability than Comparative Examples 2-1 to 2-4.
　比較例２-２及び２-４では、脱硫処理の処理温度がナイロン６６短繊維の融点に近いことから、ナイロン６６短繊維の物性低下を招いたものと推測される。 In Comparative Examples 2-2 and 2-4, since the treatment temperature of the desulfurization treatment is close to the melting point of the nylon 66 short fiber, it is presumed that the physical properties of the nylon 66 short fiber were deteriorated.
　比較例２-３及び２-４では、再生ゴム中のナイロン６６短繊維の最大粒径が大きいため、界面でのクラックの発生が起こり易いものと推測される。 In Comparative Examples 2-3 and 2-4, since the maximum particle size of the nylon 66 short fiber in the recycled rubber is large, it is presumed that cracks are likely to occur at the interface.
　本発明は、再生ゴム及びその製造方法、並びにそれを用いた伝動ベルトの技術分野において有用である。 The present invention is useful in the technical field of recycled rubber, a method for producing the same, and a transmission belt using the same.
Ｂ　ラップドＶベルト
１０　ベルト本体
１１　圧縮ゴム層
１２　接着ゴム層
１３　伸張ゴム層
１４　心線
１５　補強布
１０’　積層構造体
１１’～１３’　ゴムシート
１４’　撚り糸
１５’　布
２１　マントル
２２　円筒金型
２３　溝
３０　ベルト走行試験機
３１　駆動プーリ
３２　従動プーリ
  B Wrapped V-belt 10 Belt body 11 Compressed rubber layer 12 Adhesive rubber layer 13 Stretched rubber layer 14 Core wire 15 Reinforcement cloth 10 'Laminated structure 11' to 13 'Rubber sheet 14' Twisted thread 15 'Cloth 21 Mantle 22 Cylindrical mold 23 Groove 30 Belt running test machine 31 Drive pulley 32 Driven pulley

Claims (14)

  1. 　硫黄架橋されたエチレンプロピレンジエンモノマーを含むゴム組成物を由来とし、且つゲル分率が５０～８５質量％である再生ゴム。 Recycled rubber derived from a rubber composition containing a sulfur-crosslinked ethylene propylene diene monomer and having a gel fraction of 50 to 85% by mass.
  2. 　請求項１に記載された再生ゴムにおいて、
    　ゴム成分がエチレンプロピレンジエンモノマーのみである再生ゴム。     The recycled rubber according to claim 1,
    Recycled rubber whose rubber component is only ethylene propylene diene monomer.
  3. 　請求項１又は２に記載された再生ゴムにおいて、
    　ゴム成分の含有量が３０～７０質量％である再生ゴム。     In the recycled rubber according to claim 1 or 2,
    Recycled rubber having a rubber component content of 30 to 70% by mass.
  4. 　請求項１乃至３のいずれかに記載された再生ゴムが用いられたゴム組成物によりベルト本体の少なくとも一部が構成された伝動ベルト。 A power transmission belt comprising at least a part of a belt body made of a rubber composition using the recycled rubber according to any one of claims 1 to 3.
  5. 　請求項４に記載された伝動ベルトにおいて、
    　前記ゴム組成物には、バージンゴムがブレンドされている伝動ベルト。     The transmission belt according to claim 4,
    A transmission belt in which virgin rubber is blended with the rubber composition.
  6. 　請求項５に記載された伝動ベルトにおいて、
    　前記バージンゴムがエチレン－α－オレフィンエラストマーである伝動ベルト。     The transmission belt according to claim 5,
    A transmission belt in which the virgin rubber is an ethylene-α-olefin elastomer.
  7. 　請求項５又は６に記載された伝動ベルトにおいて、
    　前記ゴム組成物のゴム成分における前記バージンゴムの含有量が２０～８０質量％である伝動ベルト。     In the transmission belt according to claim 5 or 6,
    A transmission belt in which the content of the virgin rubber in the rubber component of the rubber composition is 20 to 80% by mass.
  8. 　請求項４乃至７のいずれかに記載された伝動ベルトにおいて、
    　前記ゴム組成物には、架橋剤として硫黄が配合されている伝動ベルト。     The power transmission belt according to any one of claims 4 to 7,
    A transmission belt in which sulfur is added to the rubber composition as a crosslinking agent.
  9. 　請求項４乃至８のいずれかに記載された伝動ベルトにおいて、
    　前記ゴム組成物には、架橋剤として有機過酸化物が配合されている伝動ベルト。     The power transmission belt according to any one of claims 4 to 8,
    A transmission belt in which an organic peroxide is blended as a crosslinking agent in the rubber composition.
  10. 　請求項４乃至９のいずれかに記載された伝動ベルトにおいて、
    　前記ゴム組成物の列理方向における１００℃での損失係数ｔａｎδが０．０４～０．１５である伝動ベルト。     The power transmission belt according to any one of claims 4 to 9,
    A power transmission belt having a loss coefficient tan δ at 100 ° C. in the line direction of the rubber composition of 0.04 to 0.15.
  11. 　硫黄架橋されたエチレンプロピレンジエンモノマーを含む架橋ゴムを粉砕し、前記粉砕した架橋ゴムに剪断応力を加えて脱硫処理を施すゲル分率が５０～８５質量％である再生ゴムの製造方法。 A method for producing a reclaimed rubber having a gel fraction of 50 to 85% by mass, wherein a crosslinked rubber containing sulfur-crosslinked ethylene propylene diene monomer is pulverized and subjected to desulfurization treatment by applying shear stress to the crushed crosslinked rubber.
  12. 　請求項１１に記載された再生ゴムの製造方法において、
    　前記粉砕した架橋ゴムの平均粒径が１０μｍ～５ｍｍである再生ゴムの製造方法。     In the manufacturing method of the reclaimed rubber according to claim 11,
    A method for producing a recycled rubber, wherein the crushed crosslinked rubber has an average particle size of 10 μm to 5 mm.
  13. 　請求項１１又は１２に記載された再生ゴムの製造方法において、
    　前記脱硫処理の処理温度を１５０～２５０℃とする再生ゴムの製造方法。     The method for producing a recycled rubber according to claim 11 or 12,
    A method for producing recycled rubber, wherein the treatment temperature of the desulfurization treatment is 150 to 250 ° C.
  14. 　請求項１１乃至１３のいずれかに記載された再生ゴムの製造方法において、
    　前記剪断応力を０．９８１～２０ＭＰａとする再生ゴムの製造方法。     In the manufacturing method of the reclaimed rubber according to any one of claims 11 to 13,
    A method for producing recycled rubber, wherein the shear stress is 0.981 to 20 MPa.
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